Published by WB Saunders
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GASTROENTEROLOGY 1998;115:500-501
GASTROENTEROLOGY 2002;122:236-237
This article has no abstract. To view the article, select the "View Print Version (PDF)" link above.
Deletion mapping of chromosome 22q. Markers appear on the linkage map (Genethon) and on the ideogram. Case numbers are shown above each map. , Allelic loss; , retention of both alleles. In noninformative loci, no circle is depicted. The smallest region of overlap is outlined by a rectangle superimposed on the maps.
Chromosomal allelic losses have a varying frequency in colorectal cancer. The aim of this study was to define the target region of allelic loss on chromosome 22q in human colorectal carcinogenesis. Fifty-seven pairs of matched normal colonic mucosa and tumor specimens from patients with colorectal cancer, as well as 15 colon cancer-derived cell lines, were genotyped using 15 microsatellite markers spanning chromosome 22q. A potential candidate gene was analyzed by a single-strand conformation polymorphism (SSCP)/direct DNA sequencing approach. After excluding 7 tumors with evidence of microsatellite instability, allelic loss was observed in 11 of the informative tumors (22%), 5 of which exhibited losses in all informative loci. The remaining 6 tumors showed variable patterns of partial allelic loss on chromosome 22q, thereby localizing a minimal region of allelic deletion between markers D22S1171 and D22S928. Physical mapping showed that this interval was 0.57 cM consisting of approximately 425 kilobases. Database searches identified the NBK/BIK gene, a proapoptotic BCL-2 family member, as a candidate gene in that region. However, SSCP/sequencing analysis excluded mutations of this gene. This study provides evidence for the involvement of putative tumor-suppressor gene(s) on chromosome 22q in human colorectal carcinogenesis. The identification of a 0.5-cM interval serves as the basis for the isolation of such a gene by positional cloning.
The potential of non-01 Vibrio cholerae as human pathogens is assuming greater clinical importance. They are also capable of producing a spectrum of illness that is not confined to the gastrointestinal or biliary tracts. We report a case of fatal non-01 Vibrio cholerae septicemia in a patient with chronic lymphocytic leukemia.
A model system using rabbit intestinal mucosal explants has been developed to examine the characteristic ultrastructural damage to the brush border induced by enteropathogenic Escherichia coli 0111. In this model, as in others, bacterial adherence to the microvillous membranes occurred in two morphologically distinct stages. Initial attachment of enteropathogenic strains of E. coli to ileal mucosa appeared to be a goblet cells and the mucous layer covering the microvilli. The next stage involved binding of enteropathogenic strains of E. coli to the bases of the microvilli that became elongated and vesiculated. Eventually, large areas of brush border effacement occurred with close apposition between bacterial and enterocyte membranes, leading to cup and pedestal formation. With a relatively large inoculum of bacteria (10(8) cfu/ml) these changes occurred within 4 h, but even with much lower inocula (10(5) cfu/ml) localized areas of damage were seen within 8 h. Although the bacteriostatic antibiotic tetracycline (700 mg/L) inhibited bacterial replication, it did not prevent the characteristic damage produced by enteropathogenic strains of E. coli. Enteropathogenic strains of E. coli 0111 were able to produce attaching effacement to gastric, duodenal, jejunal, ileal, and colonic mucosa.
Escherichia coli O157:H7 infection induces diarrhea, severe colitis, and colonic electrolyte transport abnormalities characterized by decreased Na absorption and Cl secretion. The aim of this study was to examine the role of the host inflammatory response in inducing distal colonic transport changes during infection with E. coli O157:H7. New Zealand white rabbits aged 10 days were infected with E. coli O157:H7 strain EDL933 (plasmid+, verotoxin 1+, verotoxin 2+). Studies were performed daily from day 1 to day 5 postinfection and compared with uninfected controls (10 days old). Distal colonic ion transport was studied in vitro under short-circuited conditions in Ussing chambers, and tissue inflammation was assessed by mucosal myeloperoxidase activities and mucosal neutrophil (polymorphonuclear neutrophil [PMN]) counts. In a second study, PMN infiltration was inhibited by an anti-CD18 (leukocyte adhesion molecule) monoclonal antibody, IB4, and histology and transport were studied on day 5 postinfection. Infection with O157:H7 induced diarrhea and inhibition of Na absorption by day 3. CI secretion occurred on day 5, coincident with tissue infiltration with PMN. Pretreatment with IB4 prevented histological damage and tissue infiltration with PMN, and it inhibited the transport abnormalities induced by infection alone. Infection with O157:H7 reduces Na absorption and stimulates Cl secretion in the distal colon. Disruption of the epithelium and changes in colonic electrolyte transport during enterohemorrhagic E. coli are mediated by the host inflammatory response.
A number of verotoxin-producing Escherichia coli strains isolated from sporadic cases of hemorrhagic colitis in the United States over the last 5 yr were shown to belong to serogroups other than O157:H7-the serotype originally implicated in this disease. Experimental infection of gnotobiotic piglets with five such strains (0111:NM, 0145:NM, 045:H2, 04:NM, and Ound:NM) caused diarrhea resulting from mucosal lesions in the cecum and colon that were indistinguishable from those previously described in piglets infected with E. coli O157:H7. This suggests that, as with other categories of pathogenic E. coli, several serotypes cause hemorrhagic colitis in humans. The five E. coli strains that were compared with one O157:H7 strain and with an enteropathogenic calf strain (serotype 05:NM) caused a spectrum of disease ranging from moderate diarrhea (O157:H7) to severe illness (including septicemia and death) (0111:NM). Characteristic lesions, which were identical for all seven pathogenic strains, included bacterial attachment, effacement of the microvillus border, and dissolution of the cell membranes of surface and glandular epithelium, resulting in complete cell destruction. Some piglets exhibited neurologic signs of convulsions and ataxia. It is concluded that a number of E. coli serotypes, in addition to O157:H7, fulfill the present limited criteria for enterohemorrhagic E. coli, which include association with hemorrhagic colitis, production of one or more verotoxins, possession of a large plasmid (50-70 megadaltons), and induction of distinct mucosal lesions in the large bowel of gnotobiotic piglets.
Rates and severity of Clostridium difficile infection (CDI) in hospitals in North America and Europe have increased since 2000 and correlate with dissemination of an epidemic strain characterized by higher than usual toxin A and B production, the presence of a third toxin, binary toxin, and high-level resistance to fluoroquinolone antibiotics. The strain, which is restriction endonuclease analysis group BI, pulse-field gel electrophoresis type NAP1, and polymerase chain reaction ribotype 027, is designated BI/NAP1/027. How this strain has become so widely distributed geographically and produces such severe CDI is the subject of active investigation. The deletion at position 117 of the tcdC gene, a repressor of toxin A and B production, is one possible contributor to increased levels of the toxins. The role of binary toxin is unknown. Recent isolates of BI/NAP1/027 were found to be resistant to fluoroquinolones, which is likely to contribute to the dissemination of this strain. Other virulence factors such as increased sporulation and surface layer protein adherence are also under investigation. Infections caused by this organism are particularly frequent among elderly hospitalized patients, in whom the attributable 30-day mortality is greater than 5%. Major risk factors for BI/NAP1/027 infection include advanced age, hospitalization, and exposure to specific antimicrobials, especially fluoroquinolones and cephalosporins. When CDI is severe, vancomycin treatment is more effective than metronidazole; for mild disease either agent can be used. Control of hospital outbreaks caused by BI/NAP1/027 is difficult but possible through a combination of barrier precautions, environmental cleaning, and antimicrobial stewardship.
The HLA class II gene DQB1*0301 has been linked to several cancers. This study was designed to determine if HLA-DQB1*0301 is present at altered frequency in patients with gastric, colorectal, or pancreatic adenocarcinoma. Oligotyping for HLA-DQB1*0301 was performed for 159 Caucasian patients with 160 gastrointestinal adenocarcinomas (52 gastric, 62 colorectal, and 46 pancreatic adenocarcinomas) and compared with 260 Caucasian noncancer controls. Patients with gastric adenocarcinoma underwent extended HLA class II region oligotyping. Immunoglobulin G to Helicobacter pylori was detected by enzyme-linked immunosorbent assay. HLA-DQB1*0301 was more common in patients with gastric adenocarcinoma than controls (54% vs. 27%; bonferroni-corrected chi 2 P = 0.003; odds ratio, 3.2). HLA-DQB1*0301 was not associated with colorectal or pancreatic adenocarcinoma. No other HLA-DQB1 allele and no HLA-DQA1 or transporter associated with antigen processing 2 (TAP2) allele were present at altered frequency in patients with gastric adenocarcinoma. Serological evidence for H. pylori infection was less frequent in HLA-DQB1*0301-positive patients with gastric adenocarcinoma compared with HLA-DQB1*0301-negative patients (52% vs. 88%; Fisher's Exact Test; P = 0.007). HLA-DQB1*0301 is more common in caucasian patients with gastric adenocarcinoma than noncancer controls. The mechanism linking HLA-DQB1*0301 with gastric adenocarcinoma is not likely through increased susceptibility to H. pylori infection.
Autoimmune pancreatitis (AIP) underlies 5%-11% of cases of chronic pancreatitis. An association between AIP and the human leukocyte antigen (HLA)-DRB1*0405/DQB1*0401 haplotype has been reported, but linkage disequilibrium has precluded the identification of predisposing HLA gene(s). We studied the role of single HLA genes in the development of AIP in transgenic mice. CD4(+) T-cell-negative I-Abeta chain(-/-) (Ab0) mice develop AIP spontaneously, likely due to dysregulation of CD8(+) T- cell responses. We generated Ab0 nonobese diabetic (NOD) mice transgenic for HLA-DR*0405, leading to rescue of CD4(+) T cells; we compared their susceptibility to AIP with HLA-DQ8 or HLA-DR*0401 (single) transgenic, or HLA-DR*0405/DQ8 (double) transgenic mice. CD4(+) T-cell-competent HLA-DR*0405 transgenic Ab0 NOD mice develop AIP with high prevalence after sublethal irradiation and adoptive transfer of CD90(+) T cells, leading to complete pancreatic atrophy. HLA-DR*0405 transgenic mice can also develop unprovoked AIP, whereas HLA-DR*0401, HLA-DQ8, and HLA-DR*0405/DQ8 transgenic Ab0 NOD controls all remained normal, even after irradiation and adoptive transfer of CD90(+) T cells. Pancreas histology in HLA-DR*0405 transgenic mice was characterized by destructive infiltration of the exocrine tissue with CD4(+) and CD8(+) T cells, B cells, and macrophages. Mice with complete pancreatic atrophy lost weight, developed fat stools, and had reduced levels of serum lipase activity. Because HLA-DR*0405 expression fails to protect mice from AIP, the HLA-DRB1*0405 allele appears to be an important risk factor for AIP on the HLA-DRB1*0405/DQB1*0401 haplotype. This humanized mouse model should be useful for studying immunopathogenesis, diagnostic markers, and therapy of human AIP.
To assess the possible role of increased renal thromboxane A2 (TXA2) synthesis in nonazotemic patients with cirrhosis and ascites and to establish the potential beneficial effect of inhibitors of renal TXA2 production in this clinical setting, we administered OKY 046, a selective TXA2 synthase inhibitor, 200 mg t.i.d. for 5 days, to 9 nonazotemic cirrhotic patients with ascites and avid sodium retention. OKY 046 inhibited platelet TXA2 production, as expressed by serum thromboxane B2 (TXB2) concentration, by approximately 85% (p less than 0.001 vs. baseline values) and reduced urinary TXB2 excretion by 72% (p less than 0.01). A significant increase of approximately 19% in inulin clearance was observed during the treatment (from 61.0 +/- 8.42 to 72.7 +/- 7.45 ml/min, p less than 0.05), whereas renal blood flow was unchanged (from 408.50 +/- 19.97 to 424.50 +/- 30.84 ml/min). Drug administration did not affect positive sodium balance [sodium excretion was 4.67 +/- 1.22 mEq/day before drug administration and 6.26 +/- 1.05 mEq/day during drug administration (on day 7)], plasma renin activity, plasma aldosterone concentration, or the urinary excretion of prostaglandin E2, 6-keto prostaglandin F1 alpha, or prostaglandin F2 alpha. These results suggest that renal TXA2 synthesis contributes to the regulation of renal hemodynamics in nonazotemic cirrhotic patients with ascites and avid sodium retention, but it does not seem to affect sodium balance.
Whipple's disease is a systemic, chronic, relapsing disorder caused by a combination of environmental (Tropheryma whipplei) and unknown host factors. Because it is a rare disease, the association between HLA type and Whipple's disease has been studied in only small numbers of patients; these studies have led to conflicting results. We aimed to investigate whether disease phenotype and outcome are associated with HLA type in 122 patients with Whipple's disease. Genomic DNA was collected from 103 German, 11 Italian, and 8 Austrian patients with Whipple's disease, along with 62 healthy Austrian workers exposed to T whipplei (14 stool samples contained the bacterium). HLA class I and II alleles were identified by polymerase chain reaction analysis. Patient genotypes were compared with those of healthy German and Austrian populations; data for Italian controls were obtained from the Pavia HLA bone marrow donors' bank. HLA-DRB1*13 and DQB1*06 alleles occurred significantly more frequently in patients with Whipple's disease but not in healthy individuals who had been exposed to T Whipplei. The cumulative odds ratios for disease were 2.23 for the DRB1*13 allele (P < .0001) and 2.25 for the DQB1*06 allele (P < .0001). DRB1*13 and DQB1*06 alleles were found to be risk factors in the largest HLA study ever performed in patients with Whipple's disease.
Most of the patients in this study were referred for cholecystography with complaints of excessive belching, gas pains, and selective dyspepsia. There was no correlation between these symptoms and the cholecystographic findings. Excessive gas, vague upper abdominal pain, history of previous jaundice, and intolerance to cabbage, pork, ice cream, and fatty foods were encountered more frequently in patients with normal cholecystograms than in those with cholecystographic abnormalities. It was impossible to predict the radiographic findings on the basis of symptoms. Right upper quadrant colicky pain was the only symptom showing a positive correlation with the cholecystographic findings. This was present in 23 per cent of patients having demonstrable calculi.
Acute hepatotoxicity has been described in patients exposed to either trichloroethylene or 1,1,1-trichloroethane, but there have been previous reports of chronic liver disease induced by these agents. We describe a patient who developed cirrhosis and portal hypertension after repeated bouts of acute hepatotoxicity caused by trichloroethylene and a final episode of 1,1,1-trichloroethane-induced liver injury.
Sequential changes in proliferative parameters in proximal and distal colonic crypts were studied during 1,2-dimethylhydrazine-induced carcinogenesis using [3H]thymidine autoradiography as a probe. 1,2-dimethylhydrazine (20 mg/kg) and vehicle (ethylenediaminetetraacetic acid) control rats received weekly s.c. injections for 20 wk. All animals received a pulse of [3H]thymidine before death at weeks 2, 6, 10, 16, 22, 26, or 30. In addition, 8 animals unexposed to 1,2-dimethylhydrazine or vehicle served as baseline controls. Dramatic regional differences were noted in the baseline controls. Crypt length, labeling index, and proliferative zone size were all significantly greater distally than proximally (p less than 0.05), whereas the labeling index of the proliferative zone tended to be enhanced proximally. During 1,2-dimethylhydrazine treatment the crypt length, labeling index, and proliferative zone size increased in both regions. As these parameters changed in parallel, the differences between proximal and distal colon did not change significantly during carcinogenesis. Actual tumor formation did differ, however, with tumors appearing earlier and in greater abundance in the distal colon. These findings show similar proliferative changes in both the proximal and distal colon during 1,2-dimethylhydrazine treatment and indicate that the enhanced baseline proliferative state of the distal colon compared with the proximal colon must be considered in the process of tumor formation.
Epidemiological and experimental studies have shown that dietary fiber may prevent colon cancer. Resistant starch, like dietary fiber, is not subject to digestion in the small intestine. However, it is unknown whether resistant starch inhibits colonic carcinogenesis. In vitro studies have shown that butyrate slows the growth of cultured colon cancer cells. The effect of resistant starch diet on 1,2-dimethylhydrazine-induced colonic carcinogenesis in rats was evaluated, and the colonic butyrate concentration was measured. Sprague-Dawley rats were randomly divided into five groups that were fed diets containing no fiber, 3% cellulose, 10% cellulose, 3% resistant starch, or 10% resistant starch. Colonic carcinogenesis and butyrate concentration of colonic contents and feces in each diet group were compared. Total cancer volume per rat in the 10% cellulose group was significantly lower than that in the basal group (109 +/- 54 mm3 and 247 +/- 83 mm3; P < 0.05), but the other groups showed no significant differences. The butyrate concentration in colonic content and in feces were higher in the resistant starch groups than in the cellulose groups. The resistant starch diet increased butyrate concentration but did not inhibit colonic carcinogenesis. It remains doubtful whether butyrate inhibits the proliferation of colon cancer cells.
The incidence, distribution, size, and histopathology of grossly visible intestinal tumors induced by the parenteral administration of 1,2-dimethylhydrazine dihydrochloride were examined in 32 paired rats fed a nutritionally adequate liquid diet containing 36% of total calories either as ethanol or isocaloric carbohydrates. The liquid diets were begun 4 wk before the first of four weekly injections of 1,2-dimethylhydrazine dihydrochloride. At the time of the subcutaneous application of the procarcinogen, liquid diets were omitted for 3 wk, and were replaced by a standard laboratory diet. This feeding schedule was repeated four times, and after 32 wk the animals were killed. Chronic ethanol ingestion increased the total number of rectal tumors significantly (17 vs. 6, p less than 0.02). However, alcohol had no effect on tumor size or histopathology. Chronic ethanol ingestion did not exhibit any cocarcinogenic effect in tissues other than the rectum. A 47% increase in the activity of mucosal alcohol dehydrogenase in the distal colorectum was found between chronically ethanol-fed rats and pair-fed controls (0.241 +/- 0.019 vs. 0.164 +/- 0.020 mumol X mg protein-1 X h-1, p less than 0.01). This could in part explain the cocarcinogenic effect of alcohol in this tissue. Fecal bile acids, however, do not play a role as promoters of rectal cancer under the present experimental conditions. The data give experimental support to the epidemiologic findings of an increased incidence of rectal cancer in the alcoholic.
The incidence, distribution, size, and histopathology of rat small and large bowel tumors induced by sequential administration of 1,2-dimethylhydrazine followed by either small bowel resection, 50% jejunoileal resection, or 50% jejunoileal bypass were examined in addition to measurements of transit times and beta-glucuronidase activities in large bowel contents. The results indicate that even limited small bowel resection or bypass promotes intestinal neoplasia, particularly in the large bowel, and this effect seems independent of the chronic injury imposed by suture lines. Although no differences in transit times were observed, increased beta-glucuronidase activities in both cecum and distal colon of resected but not bypassed rats was detected. Moreover, an apparent subsite redistribution of small bowel tumors to ileum and large bowel tumors to more proximal colon in bypassed rats suggests that the mechanisms involved for tumor enhancement differ substantially from those in resected rats.
We developed and validated a model to estimate the risks of mutations in the mismatch repair (MMR) genes MLH1, MSH2, and MSH6 based on personal and family history of cancer. Data were analyzed from 4539 probands tested for mutations in MLH1, MSH2, and MSH6. A multivariable polytomous logistic regression model (PREMM(1,2,6)) was developed to predict the overall risk of MMR gene mutations and the risk of mutation in each of the 3 genes. The discriminative ability of the model was validated in 1827 population-based colorectal cancer (CRC) cases. Twelve percent of the original cohort carried pathogenic mutations (204 in MLH1, 250 in MSH2, and 71 in MSH6). The PREMM(1,2,6) model incorporated the following factors from the probands and first- and second-degree relatives (odds ratio; 95% confidence intervals [CIs]): male sex (1.9; 1.5-2.4), a CRC (4.3; 3.3-5.6), multiple CRCs (13.7; 8.5-22), endometrial cancer (6.1; 4.6-8.2), and extracolonic cancers (3.3; 2.4-4.6). The areas under the receiver operating characteristic curves were 0.86 (95% CI, 0.82-0.91) for MLH1 mutation carriers, 0.87 (95% CI, 0.83-0.92) for MSH2, and 0.81 (95% CI, 0.69-0.93) for MSH6; in validation, they were 0.88 for the overall cohort (95% CI, 0.86-0.90) and the population-based cases (95% CI, 0.83-0.92). We developed the PREMM(1,2,6) model, which incorporates information on cancer history from probands and their relatives to estimate an individual's risk of mutations in the MMR genes MLH1, MSH2, and MSH6. This Web-based decision making tool can be used to assess risk of hereditary CRC and guide clinical management.
We developed intestinal biopsy procedures in chicks that were extended to humans to study the role of vitamin D in regulating intestinal adaptation to dietary calcium. By comparing biopsy specimens from rachitic chicks (D-) to those from vitamin D-supplemented chicks (D+) on otherwise identical diets, we observed that (a) the rates of calcium and phosphate accumulation by D+ duodenal or jejunal mucosa were ~50% greater than those by comparable D- mucosa, (b) alkaline phosphatase activity was three times greater in D+ duodenal mucosa brush border preparations than D- preparations, and (c) calcium binding activity was 10 times greater in the cytosol from D+ duodenal mucosa than from D- duodenal mucosa. We then evaluated the calcium and phosphate uptake and alkaline phosphatase activity of duodenal mucosal specimens obtained each week from 15 subjects ingesting, in successive weeks, 100 mg calcium per day (week 1) and 1000 mg calcium per day (week 2). Serum levels of 1,25-dihydroxyvitamin D, immunoreactive parathyroid hormone, calcium, and phosphorus were determined on the day the biopsy specimens were obtained. The subjects were prospectively selected to provide a range of basal 1,25-dihydroxyvitamin D levels from low to high, and included four osteoporotic, five control, and six hyperparathyroid subjects. The change from the 100-mg to 1000-mg calcium diet resulted in a fall of serum 1,25-dihydroxyvitamin D levels and duodenal calcium and phosphate uptake and alkaline phosphatase activity, with no change in serum calcium in the control subjects. Similar effects were observed in the osteoporotic subjects. The hyperparathyroid subjects experienced an increase in serum calcium and failed to reduced their serum 1,25-dihydroxyvitamin D levels on the high calcium diet. These hyperparathyroid subjects had the highest duodenal alkaline phosphatase activities and serum 1,25-dihydroxyvitamin D levels and the least consistent response of any intestinal function to the change in dietary calcium. We observed a strong correlation between duodenal alkaline phosphatase activity and serum 1,25-dihydroxyvitamin D levels on the low calcium diet (r = 0.777, p < 0.01), and between the change in these parameters due to dietary calcium (r = 0.742, p < 0.01). We concluded that intestinal adaptation to dietary calcium can be studied with duodenal biopsy specimens, that changes in duodenal alkaline phosphatase activity reflect the influence of dietary calcium on 1,25-dihydroxyvitamin D levels, and that the failure of hyperparathyroid subjects to adapt to dietary calcium is related to the failure of dietary calcium to lower 1,25-dihydroxyvitamin D levels in these subjects.
Effective chemotherapy for pancreatic cancer is urgently needed. The aim of this study was to compare the anti-proliferative activity of a new vitamin D3 analogue, 22-oxa-1,25-dihydroxyvitamin D3 (22-oxa-calcitriol), on pancreatic cancer cells lines with that of 1,25-dihydroxyvitamin D3 (calcitriol) with analysis of vitamin D receptor status. Antiproliferative effects of both agents were compared using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method and by measuring the tumor size of xenograft inoculated into athymic mice. Vitamin D receptor contents by Scatchard analysis and mutational analysis of receptor complementary DNA were performed. In vitro, 22-oxa-calcitriol and calcitriol markedly inhibited the proliferation (3 of 9 cell lines) and caused a G1 phase cell cycle arrest by appearance of numerous domes. In vivo, 22-oxa-calcitriol inhibited the growth of BxPC-3 xenografts more significantly than calcitriol without including hypercalcemia. Hs 766T, showing no response to either agent, had the second highest receptor contents with no abnormalities in its primary structure deduced by receptor complementary DNA. 22-oxa-calcitriol may provide a more useful tool for the chemotherapy of pancreatic cancer than calcitriol. Also, the susceptibility of the cell lines to both agents is not well determined by evaluating either the contents or the mutation of vitamin D receptor.
Hypercalcemia may occur in various granulomatous diseases. Two patients with Crohn's disease who had hypercalcemia, hypercalciuria, and excessively high serum levels of 1,25-dihydroxyvitamin D [1,25(OH)2D] are described. Both had numerous noncaseating, epithelioid granulomas in bowel biopsy samples. A direct correlation was observed between serum 1,25(OH)2D levels and both serum and urinary calcium concentrations. Also, calcium and 1,25(OH)2D levels strongly paralleled the clinical activity of disease. Prompt therapy with prednisone in the patient who had symptomatic hypercalcemia and with prednisone and mesalamine in the other patient without hypercalcemic symptoms led to normalization of calcium and serum 1,25(OH)2D levels, but 25-hydroxyvitamin D [25(OH)D] levels remained unchanged. Four months after discharge, recurrence of Crohn's disease symptomatology together with an increase in calcium and serum 1,25(OH)2D levels was observed in 1 patient; after increasing the prednisone dose, levels decreased and rapid clinical resolution was noted. These cases appear to be the first reported instances of hypercalcemia in patients with Crohn's disease. Excessive synthesis of 1,25(OH)2D may have been inhibited by an action of corticosteroids on the 1alpha-hydroxylation of 25(OH)D in the activated macrophage of Crohn's granulomas. Crohn's disease should be added to the list of granulomatous diseases responsible for 1,25(OH)2D-mediated hypercalcemia.
Oligosaccharide modifications induce various functional changes in immune cells. The galactose-deficient fraction of fucosylated IgG oligosaccharides is increased, whereas that of β-1,4-galactosyltransferase I (B4GalTI) is reduced, in patients with Crohn's disease. We investigated the role of oligosaccharide modification in the pathophysiology of colitis using B4galt1-deficient mice. Colitis severity was compared between B4galt1(+/-) and B4galt1(+/+) mice. B cells isolated from B4galt1(+/-) and B4galt1(+/+) mice were adoptively transferred to recombination activating gene 2(-/-) mice, in which colitis was induced by administration of CD4(+)CD62L(+) T cells. Cell-surface glycan profiles were determined by lectin microarray analysis. Cytokine production was determined in a coculture of various types of cells isolated from either B4galt1(+/-) or B4galt1(+/+) mice. Colitis induction by dextran sodium sulfate or trinitrobenzene sulfonic acid was significantly reduced in B4galt1(+/-) mice, which had galactose deficiency in IgG oligosaccharides (similar to patients with Crohn's disease) compared with B4galt1(+/+) mice. Amelioration of colitis was associated with increased production of interleukin-10 by macrophages in B4galt1(+/-) mice. Colitis induction in recombination activating gene 2(-/-) mice by administration of CD4(+)CD62L(+) T cells was reduced by cotransfer of B cells isolated from B4galt1(+/-), but not from B4galt1(+/+) mice. Lectin microarray analysis revealed increased expression of polylactosamines on B4galt1(+/-) B cells and macrophages, compared with B4galt1(+/+) cells. The production of interleukin-10 from macrophages was induced via their direct interaction with B4galt1(+/-) B cells. Altered oligosaccharide structures on immune cells modulate mucosal inflammation. Oligosaccharides in immune cells might be a therapeutic target for inflammatory bowel diseases.
The first experimental production of Mallory bodies was reported by Denk et al. in 1975 in mice fed griseofulvin. We discovered a second chemical capable of producing Mallory bodies in the mouse liver in a manner similar to griseofulvin. Male Swiss albino mice were fed a powdered standard diet containing 2.5% of 3,5-diethoxycarbonyl-1,4-dihydrocollidine up to 95 days. The animals were killed at intervals and their livers were examined by light and electron microscopy. In general, the morphologic changes in the liver were similar to, but more marked than, those seen in griseofulvin-fed mice. Mallory bodies were first observed in the livers of mice killed at 40 days. In our previous experiment using griseofulvin, we first observed Mallory bodies in mice killed at 61 days. These observations suggest that 3,5-diethoxycarbonyl-1,4-dihydrocollidine may be more effective than griseofulvin in the production of Mallory bodies in mice.
Cholestasis is one of the principal manifestations of liver disease and often results from disorders involving bile duct epithelia rather than hepatocytes. A range of disorders affects biliary epithelia, and no unifying pathophysiologic event in these cells has been identified as the cause of cholestasis. Here we examined the role of the inositol 1,4,5-trisphosphate receptor (InsP3R)/Ca(2+) release channel in Ca(2+) signaling and ductular secretion in animal models of cholestasis and in patients with cholestatic disorders. The expression and distribution of the InsP3R and related proteins were examined in rat cholangiocytes before and after bile duct ligation or treatment with endotoxin. Ca(2+) signaling was examined in isolated bile ducts from these animals, whereas ductular bicarbonate secretion was examined in isolated perfused livers. Confocal immunofluorescence was used to examine cholangiocyte InsP3R expression in human liver biopsy specimens. Expression of the InsP3R was selectively lost from biliary epithelia after bile duct ligation or endotoxin treatment. As a result, Ca(2+) signaling and Ca(2+)-mediated bicarbonate secretion were lost as well, although other components of the Ca(2+) signaling pathway and adenosine 3',5'-cyclic monophosphate (cAMP)-mediated bicarbonate secretion both were preserved. Examination of human liver biopsy specimens showed that InsP3Rs also were lost from bile duct epithelia in a range of human cholestatic disorders, although InsP3R expression was intact in noncholestatic liver disease. InsP3-mediated Ca(2+) signaling in bile duct epithelia appears to be important for normal bile secretion in the liver, and loss of InsP3Rs may be a final common pathway for cholestasis.
The action of several exocrine pancreas secretagogues depends on the second messenger inositol 1,4, 5-trisphosphate (IP3), which, via endoplasmic reticulum-located IP3 receptors, mobilizes intracellular Ca2+ stores. Signaling pathways like this one are regulated at multiple loci. To determine whether IP3 receptors are one of these loci, we measured IP3 receptor concentration, distribution, and modification in secretagogue-stimulated rat pancreatic acinar cells. Isolated rat pancreatic acinar cells were exposed to cholecystokinin and other secretagogues, or rats were injected intraperitoneally with cerulein. Then samples of cells or pancreata were probed for IP3 receptor content and distribution as well as for ubiquitin association with IP3 receptors. Secretagogues rapidly down-regulated acinar cell IP3 receptors both in vitro and in vivo. They also elicited receptor redistribution and caused receptors to become ubiquitinated, indicating that the ubiquitin/proteasome proteolytic pathway contributes to the down-regulation. Surprisingly, however, proteasome inhibitors did not block IP3 receptor down-regulation, and phospholipase Cbeta1 and protein kinase C also were down-regulated. Thus, secretagogues simultaneously activate an additional proteolytic pathway. Secretagogues rapidly down-regulate IP3 receptors and other proteins involved in intracellular signaling by a mechanism that involves, but is not limited to, the ubiquitin/proteasome pathway. Loss of these proteins may account for the disruption of Ca2+ mobilization that occurs in models of acute pancreatitis, and may contribute to cell adaptation under physiological conditions.
Ca2+ regulates cell functions through signaling patterns such as Ca2+ oscillations and Ca2+ waves. The type I inositol 1,4,5-trisphosphate receptor is thought to support Ca2+ oscillations, whereas the type III inositol 1,4,5-trisphosphate receptor is thought to initiate Ca2+ waves. The role of the type II inositol 1,4,5-trisphosphate receptor is less clear, because it behaves like the type III inositol 1,4,5-trisphosphate receptor at the single-channel level but can support Ca2+ oscillations in intact cells. Because the type II inositol 1,4,5-trisphosphate receptor is the predominant isoform in liver, we examined whether this isoform can trigger Ca2+ waves in hepatocytes. The expression and distribution of inositol 1,4,5-trisphosphate receptor isoforms was examined in rat liver by immunoblot and confocal immunofluorescence. The effects of inositol 1,4,5-trisphosphate on Ca2+ signaling were examined in isolated rat hepatocyte couplets by using flash photolysis and time-lapse confocal microscopy. The type II inositol 1,4,5-trisphosphate receptor was concentrated near the canalicular pole in hepatocytes, whereas the type I inositol 1,4,5-trisphosphate receptor was found elsewhere. Stimulation of hepatocytes with vasopressin or directly with inositol 1,4,5-trisphosphate induced Ca2+ waves that began in the canalicular region and then spread to the rest of the cell. Inositol 1,4,5-Trisphosphate-induced Ca2+ signals also increased more rapidly in the canalicular region. Hepatocytes did not express the ryanodine receptor, and cyclic adenosine diphosphate-ribose had no effect on Ca2+ signaling in these cells. The type II inositol 1,4,5-trisphosphate receptor establishes a pericanalicular trigger zone from which Ca2+ waves originate in hepatocytes.
Several groups have reported that administration of fructose-1,6-bisphosphate (FBP) reduces ischemic injury. The aim of this study was to determine the protective effect of FBP on the impairment of mitochondrial oxidative phosphorylation by ischemia-reperfusion injury in the rat liver. The respiratory control ratio (RCR) and the adenine nucleotide content of mitochondria isolated from ischemic and reperfused livers with or without FBP treatment were measured. In FBP-treated livers, the cellular adenosine triphosphate level was restored to more than 50% of normal after 120 minutes of reperfusion following 120 minutes of ischemia, whereas that of control livers only reached 15% of normal. The RCR and the adenine nucleotide content of mitochondria isolated from FBP-treated livers were significantly higher than those of mitochondria from control livers after ischemia and reperfusion. FBP strongly suppressed the formation of lipid peroxides during reperfusion. In vitamin E-deficient rats, the RCR decreased markedly during reperfusion, but FBP protected the mitochondria against reperfusion injury. FBP has a protective effect against ischemia-reperfusion injury on the liver and especially preserves the oxidative phosphorylation capacity of hepatic mitochondria.
Fructose-1,6-bisphosphatase (FBP)-1 is a gluconeogenic enzyme that regulates glucose metabolism and insulin secretion in β cells, but little is known about how its transcription is controlled. The zinc finger protein ZBTB20 regulates glucose homeostasis, so we investigated its effects on expression of FBP-1. We analyzed gene expression using real-time reverse-transcription polymerase chain reaction, immunoblotting, and immunohistochemistry. We generated mice with β cell-specific disruption of Zbtb20 using Cre/LoxP technology. Expression of Zbtb20 in β cells was reduced using small interfering RNAs, and promoter occupancy and transcriptional regulation were analyzed by chromatin immunoprecipitation and reporter assays. ZBTB20 was expressed at high levels by β cells and other endocrine cells in islets of normal mice; expression levels were reduced in islets from diabetic db/db mice. Mice with β cell-specific knockout of Zbtb20 had normal development of β cells but had hyperglycemia, hypoinsulinemia, glucose intolerance, and impaired glucose-stimulated insulin secretion. Islets isolated from these mice had impaired glucose metabolism, adenosine triphosphate production, and insulin secretion after glucose stimulation in vitro, although insulin secretion returned to normal levels in the presence of KCl. ZBTB20 knockdown with small interfering RNAs impaired glucose-stimulated insulin secretion in the β cell line MIN6. Expression of Fbp1 was up-regulated in β cells with ZBTB20 knockout or knockdown; impairments to glucose-stimulated insulin secretion were restored by inhibition of FBPase activity. ZBTB20 was recruited to the Fbp1 promoter and repressed its transcription in β cells. The transcription factor ZBTB20 regulates β cell function and glucose homeostasis in mice. It might be a therapeutic target for type 2 diabetes mellitus.
One thousand consecutively autopsied livers were examined for intrahepatic heterotopic pancreas. Heterotopic pancreas in the liver was found in 41 (4.1%) of the 1000 livers. It occurred with nearly equal frequency in "normal" livers and variously diseased livers. Histologically, heterotopic pancreas was situated exclusively in the large- and medium-sized portal tracts, and its size ranged from 250-900 microns in diameter. It was intermingled with intrahepatic peribiliary glands and appeared to communicate with bile duct lumina. Heterotopic pancreas consisted of three cell types: acinar cells with eosinophilic zymogenlike granules, clear cells resembling centriacinar cells, and ductular elements. Langerhans' islets were not found in any cases. Immunohistochemically, constituent cells of heterotopic pancreas contained pancreatic alpha-amylase and trypsin but lacked argentaffin and argyrophilic cells as well as insulin-, glucagon-, and somatostatin-immunoreactive endocrine cells. Ultrastructurally, acinar cells contained many dense granules regarded as zymogen granules. It is indicated that intrahepatic heterotopic pancreas occurs in large portal tracts. It may modify hepatic bile by secreting pancreatic enzymes into intrahepatic bile duct lumina.
Malabsorption and deficiency of vitamin E causing neurological degeneration are common consequences of chronic childhood cholestatic liver disease. The objective of this study was to determine the long-term efficacy and safety of d-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS) in correcting vitamin E deficiency in children with chronic cholestasis who were unresponsive to other forms of oral vitamin E. Sixty vitamin E-deficient children with chronic cholestasis unresponsive to 70-212 of oral vitamin E were entered into a trial at eight centers in the United States. After initial evaluation, treatment was started with 25 of TPGS. Vitamin E status, neurological function quantitated by a specific scoring system, and clinical and biochemical parameters were monitored during therapy. All children responded to TPGS with normalization of vitamin E status. Neurological function, which had deteriorated before entry in the trial, improved in 25 patients, stabilized in 27, and worsened in only 2 after a mean of 2.5 years of therapy. No adverse effects were observed. TPGS (20-25 appears to be a safe and effective form of vitamin E for reversing or preventing vitamin E deficiency during chronic childhood cholestasis.
Transvenous liver biopsy was attempted 1033 times in 932 patients in whom percutaneous liver biopsy was contraindicated. A hepatic tissue specimen was obtained in 1000 out of these 1033 attempts. The specimen was unfragmented and/or large enough to allow correct evaluation of liver architecture in 518 of the 807 successful biopsies (64.2%) in patients with liver fibrosis or cirrhosis and in 191 of the 193 successful biopsies (98.9%) in patients with nonfibrotic lesion of the liver. Transvenous liver biopsy was followed by no or minor complication in all our patients except for one who suffered fatal intraperitoneal bleeding due to perforation of the liver capsule. It is concluded that transvenous liver biopsy is a workable, efficient, safe procedure for obtaining hepatic tissue specimens and that this method is essential in a department of hepatology.
Treatment of vitamin E deficiency during chronic childhood cholestasis is hampered by the poor intestinal absorption of available oral preparations of vitamin E when bile flow is severely impaired; thus parenteral vitamin E has been the only effective therapy for many children with this problem. We studied the intestinal absorption, efficacy, and safety of a water-soluble oral form of vitamin E, d-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS), in 22 children (7 mo to 19 yr old) with severe cholestasis and vitamin E deficiency who were unresponsive to massive oral doses (100-200 IU/ of dl-alpha-tocopherol. The results of oral vitamin E tolerance tests showed that TPGS was well absorbed in virtually all study subjects, that TPGS intestinal absorption was superior to that of dl-alpha-tocopherol, and that TPGS absorption in teenage children with chronic cholestasis was similar to that of normal adults. In addition, 1.7% +/- 1.6% (mean +/- SD) of the administered polyethylene glycol 1000 contained in the TPGS was absorbed and excreted in the urine of the 13 subjects analyzed, compared with 3.0% +/- 1.3% in 4 normal adults. A chronic oral dose of 15-25 IU/ of TPGS corrected the biochemical vitamin E deficiency state over 1-19 mo (mean, 10.6 mo) of TPGS therapy. No clinical or biochemical evidence of gastrointestinal, renal, hepatic, or hematologic toxicity was demonstrated. This study suggests that TPGS administered orally in a dose of 15-25 IU/ may be a safe and effective form of vitamin E for prevention and correction of vitamin E deficiency during severe childhood cholestasis.
We prospectively evaluated risk factors in 1000 consecutive patients who underwent liver biopsy: 829 outpatients and 171 inpatients. The two groups were similar except that the outpatient group had a higher percentage of patients with hepatitis-cirrhosis and a lower percentage with neoplasia when compared with the inpatient group (P less than 0.01). The inpatient group had more relative contraindications (P less than 0.01). Among the 1000 patients, none died and none required laparotomy. If moderate to severe pain or hypotension or both developed (5.9%), they first became manifest during a 3-hr period of observation after biopsy. Forty-four outpatients (5.3%) were hospitalized; 39 were dismissed within 36 hr and 5 within 4 days. Complications were more often experienced by those with relative contraindications (P less than 0.05) and increased number of passes (P less than 0.01). Inpatients with hepatitis-cirrhosis experienced more complications (P less than 0.05) than did patients with other diagnoses (12.8 versus 3.8%). Complications were not related to type of needle, site of entry, or experience of operator. Liver biopsy as an outpatient procedure is safe if facilities are available for 3 hr of observation and hospital support; 5% of patients will require immediate hospitalization.
The transport of electrolytes by the human colon has been studied by perfusing the entire colon with isotonic solutions containing different concentrations of sodium, chloride, potassium, and bicarbonate. Absorption of sodium and chloride against large concentration gradients contrasted with transport characteristics of the small intestine, emphasizing the normal conserving function of the colon for these electrolytes. Potassium and bicarbonate are secreted by the colon; chloride in the lumen facilitates the secretion of bicarbonate. However, both potassium and bicarbonate are absorbed when sufficiently large gradients of concentration between colon and blood are achieved. Although water is absorbed effectively by the colon, the process is probably passive, after osmotic gradients are produced by absorption of sodium. Relationships between ionic transport are such that net absorption of chloride balances the flux of sodium into the circulation; the reversed flux of sodium into the colon is accompanied by secretion of bicarbonate.
Limited data are available regarding TP53 gene alterations in Barrett's esophagus. This study was undertaken to characterize TP53 mutations and p53 protein immunoreactivity in cancers and preinvasive lesions of Barrett's esophageal mucosa. Seventeen Barrett's adenocarcinomas were examined by polymerase chain reaction amplification, denaturant gradient gel electrophoresis, and sequencing for the presence of TP53 mutations in exons 5-8. In 9 cases, Barrett's epithelium adjacent to the cancer was investigated. p53 protein immunoreactivity was studied with PAb 1801. Sixteen mutations were found in 15 adenocarcinomas, including 10 missense, 3 nonsense, 1 frameshift, and 2 mutations located within consensus splice donor and acceptor sequences. All nucleotide substitutions were transitions. Eight of the 12 transitions involving a GC base pair occurred within the context of a CpG dinucleotide. p53 immunostaining was present in all 10 cases with missense mutations and in 1 case without a detectable mutation. The surrounding Barrett's mucosa showed TP53 mutations identical to that observed in the carcinoma in only 3 of 5 specimens showing high-grade dysplasia. TP53 gene mutations and p53 protein immunostaining are present in a majority of Barrett's adenocarcinomas. Our results suggest that these mutations are involved at an early stage during malignant transformation of Barrett's esophagus.
The chronic hypergastrinemia in diseases such as the Zollinger-Ellison syndrome has trophic effects on the gastric mucosa, causing increased parietal cell mass reflected by increased maximal acid output (MAO) and basal acid output (BAO). The time course for the development of these gastric changes in humans is unknown, and controversy exists regarding whether reversal of the hypergastrinemia results in rapid normalization of gastric secretory function. To address these uncertainties, gastric secretory function was prospectively evaluated in 20 patients with the Zollinger-Ellison syndrome undergoing successful curative resection of gastrinoma. Each patient had gastric acid measurements, imaging studies, fasting serum gastrin and secretin provocative testing preoperatively, postoperatively at 3-6 months, and yearly thereafter. Preoperative mean BAO was 39 mEq/h, MAO 56 mEq/h, BAO-MAO ratio 0.73, and fasting gastrin output 1020 pg/mL. All patients were evaluated at 6 months, 17 at 1 year, 15 at 2 years, 13 at 3 years, and 9 at 4 years. By 3-6 months, MAO decreased by 50% in men (mean, 30 mEq/h) and by 35% in women (mean, 29 mEq/h) and then remained relatively unchanged for up to 4 years. Before surgery, 14 of 20 patients (70%) had an elevated MAO, whereas 4 years after resection, none of 9 patients had elevated levels. By 3-6 months, BAO decreased by 75% and remained unchanged for up to 4 years. At 3-6 months, 56% of patients were mild hypersecretors and 67% remained hypersecretors up to 4 years. Preoperatively, the BAO-MAO ratio was elevated in 16 of 20 patients (80%); postoperatively, only 5 of 18 patients (28%) at 3-6 months, 2 of 15 (13%) at 1 year, and 2 of 10 (20%) at 4 years continued to have elevated ratios. Preoperatively, the mean ranitidine dose was 1597 mg/day, whereas after surgery the mean dose was 535 mg/day at 3-6 months and approximately 300 mg/day at 1-4 years with 8 patients requiring no antisecretory drug. These results show that the trophic effects of chronic hypergastrinemia are, in general, rapidly reversible with a 50% decrease in MAO within 3-6 months of cure. Similarly, BAO decreased by 75% within 3-6 months. Despite these decreases, careful monitoring of acid secretion is required after reversal of the chronic hypergastrinemia in diseases such as the Zollinger-Ellison syndrome, because 55% of patients at 3-6 months and up to 67% at 4 years continue to remain mild hypersecretors and require low doses of antisecretory drugs.
Top-cited authors
William J Sandborn
  • University of California, San Diego
Nicholas Talley
  • University of Newcastle
Michael Camilleri
  • Mayo Foundation for Medical Education and Research
Stephan R Targan
  • Cedars-Sinai Medical Center
Jaime Bosch
  • University of Barcelona and Inselspital, Bern University