K T Izutsu

University of Washington Seattle, Seattle, Washington, United States

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Publications (78)258.86 Total impact

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    ABSTRACT: Chronic graft-versus-host disease (cGVHD) is an immune-mediated disorder and is the major long-term complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT). The oral mucosa including the salivary glands is affected in the majority of cGVHD patients; however, at present there is only a limited understanding of disease pathobiology. In this study, we performed a quantitative proteomic analysis of saliva pooled from oral cGVHD(+) and oral cGVHD(-) patients using iTRAQ (isobaric Tags for Relative and Absolute Quantification) labeling, followed by tandem mass spectrometry. Among 249 salivary proteins identified by tandem mass spectrometry, 82 proteins exhibited altered expression in oral cGVHD patients compared to allo-HSCT patients without oral cGVHD. Many of the identified proteins function in innate or acquired immunity, or are associated with tissue maintenance functions such as proteolysis or the cytoskeleton. Using ELISA immunoassays, we further confirmed that two of these proteins, IL-1 receptor antagonist and Cystatin B, showed decreased expression in patients with active oral cGVHD (P < 0.003). Receiver Operator Characteristic analysis revealed that these two markers were able to distinguish oral cGVHD with a sensitivity of 85% and specificity of 60%, and showed slightly better discrimination in newly diagnosed patients studied within 12 months of allo-HSCT transplantation (sensitivity, 92%; specificity 73%). In addition to identifying novel potential salivary cGVHD biomarkers, our study demonstrates that there is coordinated regulation of protein families involved in inflammation, anti-microbial defense and tissue protection in oral cGVHD that may also reflect changes in salivary gland function and damage to the oral mucosa.
    Biology of blood and marrow transplantation: journal of the American Society for Blood and Marrow Transplantation 04/2014; 20(7). DOI:10.1016/j.bbmt.2014.03.031 · 3.35 Impact Factor
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    ABSTRACT: Objectives: Chronic graft-versus-host disease (cGVHD) is a long term and often life-threatening inflammatory condition that affects 30-70% of patients who undergo allogeneic hematopoietic stem cell transplantation (allo-HSCT). In the oral cavity, erythema, lichenoid changes, mucosal atrophy, xerostomia, and infections are common symptoms; hence, oral cGVHD often clinically resembles other autoimmune conditions such as Sjögrens syndrome and oral lichen planus. While the risk factors for cGVHD are well known, the etiology and underlying pathophysiology of oral cGVHD are poorly understood. The goal of this study was to utilize quantitative mass spectrometry to identify potential protein biomarker(s) of oral cGVHD. Methods: Whole unstimulated saliva was collected from 10 cGVHD patients and 10 healthy age-matched allo-HSCT controls (mean age, 49 years). At the time of saliva collection, patients were an average of 19.7 months post-transplantation (range 6.7-62.7 months). Saliva was pooled from each patient group, labeled with iTRAQ (isobaric Tags for Relative and Absolute Quantification) reagents and subjected to quantitative, tandem (MALDI-TOF/TOF) mass spectrometry. Selected salivary proteins were validated by ELISA assay. Results: Among 249 proteins identified by tandem mass spectrometry, 59 proteins (23.7%) were significantly upregulated in cGVHD saliva compared to healthy allo-HSCT patients, as shown by iTRAQ, while 39 proteins (15.7%) were downregulated. Gene Ontology analysis demonstrated that 49 proteins (50%) were secreted molecules, with many being involved in innate immunity, inflammation and/or tissue protection. Using an ELISA assay, we confirmed that Interleukin-1 Receptor Antagonist (IL-1Ra) was downregulated in the saliva of cGVHD patients (N=43) compared with healthy allo-HSCT patients (N=20) (p<0.05). Conclusions: Using quantitative, global proteomic profiling, we identified 98 salivary proteins that were significantly altered in expression in patients with oral cGVHD. IL-1Ra, a negative regulator of IL-1 signaling, was downregulated in cGVHD patients compared with healthy allo-HSCT controls and represents one potential oral biomarker of this chronic inflammatory condition.
    IADR/AADR/CADR General Session and Exhibition 2013; 03/2013
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    Brain 02/2011; 134(Pt 7):e178. DOI:10.1093/brain/awr015 · 10.23 Impact Factor
  • Special Care in Dentistry 06/2008; 5(6):274 - 277. DOI:10.1111/j.1754-4505.1985.tb00593.x
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    ABSTRACT: We previously demonstrated that high external [Ca(2+)] activated two Ca(2+) currents in human gingival keratinocytes (HGKs): an initial small I(CRAC)-like current and a second large nonspecific cation current (Fatherazi S, Belton CM, Cai S, Zarif S, Goodwin PC, Lamont RJ, Izutsu KT; Pflugers Arch 448:93-104, 2004). It was recently shown that TRPC1, a member of the transient receptor potential protein family, is a component of the store-operated calcium entry mechanism in keratinocytes. To further elucidate the molecular identity of these channels, we investigated the expression of TRPC4 in gingival tissue and in cultured keratinocytes, and the effect of knockdown of TRPC4 expression on the Ca(2+) currents and influx. Immunohistochemistry showed TRPC4 was present in gingival epithelium as well as in HGKs cultured in different [Ca(2+)]s. Results from tissue and cultured HGKs demonstrated TRPC4 expression decreased with differentiation. Knockdown of TRPC4 in proliferating HGKs with antisense oligonucleotides significantly reduced the intracellular [Ca(2+)] increase obtained upon exposure to high external [Ca(2+)]. Antisense knockdown of TRPC4 expression was confirmed by reverse transcriptase polymerase chain reaction, Western blot, and immunofluorescence microscopy of transfected HGKs. Immunofluorescence microscopy and patch clamp measurements in Lucifer-yellow-tagged, antisense-treated HGKs showed attenuation of TRPC4 expression levels as well as attenuation of the I(CRAC)-like current in the same cell, whereas the large nonspecific cation current was unchanged but significantly delayed. Cells transfected with a scrambled TRPC4 oligonucleotide showed no change in either the I(CRAC)-like or nonspecific currents. The results indicate that TRPC4 is an important component of the I(CRAC)-like channel in HGKs.
    Pflügers Archiv - European Journal of Physiology 04/2007; 453(6):879-89. DOI:10.1007/s00424-006-0156-4 · 3.07 Impact Factor
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    ABSTRACT: External calcium ion concentration is a major regulator of epidermal keratinocyte differentiation in vitro and probably also in vivo. Regulation of calcium-induced differentiation changes is proposed to occur via an external calcium-sensing, signaling pathway that utilizes increases in intracellular calcium ion concentration to activate differentiation-related gene expression. Calcium ion release from intracellular stores and calcium ion influx via store-operated calcium-permeable channels are key elements in this proposed signaling pathway; however, the channels involved have not yet been identified. The present report shows that human gingival keratinocytes (HGKs) also undergo calcium-induced differentiation in vitro as indicated by involucrin expression and morphological changes. Moreover, TRPC1, which functions as a store-operated calcium channel in a number of cell types, including epidermal keratinocytes, is expressed in both proliferating and differentiating HGKs. Transfection of HGKs with TRPC1 siRNA disrupted expression of TRPC1 mRNA and protein compared with transfection with scrambled TRPC1 siRNA. Cells with disrupted TRPC1 expression showed decreased calcium-induced differentiation as measured by involucrin expression or morphological changes, as well as decreased thapsigargin-induced calcium ion influx, and a decreased rate of store calcium release. These results indicate that TRPC1 is involved in calcium-induced differentiation of HGKs likely by supporting a store-operated calcium ion influx.
    Pflügers Archiv - European Journal of Physiology 05/2006; 452(1):43-52. DOI:10.1007/s00424-005-0001-1 · 3.07 Impact Factor
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    ABSTRACT: Porphyromonas gingivalis, a periodontal pathogen, can invade primary cultures of gingival epithelial cells. This invasion was significantly inhibited (74–81%) by thapsigargin and 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid, acetoxymethyl ester (BAPTA/AM), but not by EDTA or amiloride. Release of Ca2+ from an intracellular store and the subsequent increase in cytosolic [Ca2+] may, therefore, be involved in the invasion process, while Ca2+ influx is not. Moreover, cytosolic [Ca2+] was found to increase transiently in about 30% of gingival epithelial cells acutely exposed to P. gingivalis, but not in unexposed cells, or in cells exposed to noninvasive Escherichia coli. These findings indicate that P. gingivalis invasion of epithelial cells is correlated with activation of [Ca2+]-dependent host cell signaling systems.
    FEMS Microbiology Letters 01/2006; 144(2‐3):145 - 150. DOI:10.1111/j.1574-6968.1996.tb08521.x · 2.72 Impact Factor
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    ABSTRACT: Extracellular calcium is an important regulator of keratinocyte differentiation. An increase in intracellular calcium ion concentration is required for activation of calcium-induced keratinocyte differentiation. The signaling elements in this differentiation response include the calcium sensing receptor, phospholipase C, release of calcium ions from intracellular stores, and store-operated calcium channels. Nothing is currently known about the calcium-entry channels activated by the increase in external calcium. However, canonical transient receptor potential (TRPC) channels have been identified as store-operated calcium channels in several tissues. To examine the expression of TRPC channels in human gingival keratinocytes (HGKs) in primary culture under both low calcium (basal) and high calcium (differentiating) conditions, and in gingival tissue. TRPC channel expression was evaluated via RT-PCR, Western blots, and immunohistology. TRPC1, TRPC5, TRPC6 and TRPC7 mRNAs were detected in undifferentiated keratinocytes. Their levels initially increased, then decreased during calcium-induced differentiation. TRPC1 and TRPC6 protein expression reflected these changes. TRPC channels are present in both proliferating and differentiating keratinocytes in primary culture and in gingival tissue. The above expression patterns suggest that these channels may be involved in calcium-induced differentiation of keratinocytes.
    Journal of Dermatological Science 11/2005; 40(1):21-8. DOI:10.1016/j.jdermsci.2005.06.005 · 3.34 Impact Factor
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    ABSTRACT: Calcium-sensing receptor (CaSR) expression and function were studied in proliferating and differentiating cultured human gingival keratinocytes (HGKs). CaSR mRNA and protein were present in proliferating HGKs cultured in 0.03 mM [Ca(2+)] and decreased in cells induced to differentiate by culturing in 1.2 mM [Ca(2+)] for 2 days. CaSR protein was also detected in gingival tissue. Exposure to 10 mM extracellular [Ca(2+)] activated two sequential whole-cell currents. The first was a small, transient calcium release activated calcium current I(CRAC)-like current with an inwardly rectifying I-V curve. The second current was larger with a linear I-V curve. Both currents were significantly decreased in differentiating cells. Neither neomycin nor gadolinium induced changes in whole cell currents nor in intracellular [Ca(2+)], but neomycin inhibited the late large current. Extracellular Ca(2+) increased intracellular [Ca(2+)] of proliferating HGKs in a dose-dependent fashion. Comparison of the time-courses of the whole-cell currents and the intracellular [Ca(2+)] responses indicated both induced currents supported a Ca(2+) influx. Extracellular [Mg(2+)] changes did not affect intracellular [Ca(2+)]. La(3+) and 2-APB inhibited the whole cell current and intracellular [Ca(2+)] changes. The results indicate that the CaSR signaling response likely plays a major role in initiating Ca(2+) induced differentiation responses in HGKs.
    Pflügers Archiv - European Journal of Physiology 05/2004; 448(1):93-104. DOI:10.1007/s00424-003-1223-8 · 3.07 Impact Factor
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    ABSTRACT: The periodontal pathogen Porphyromonas gingivalis modulates epithelial cell signal transduction pathways including Ca2+ signaling, and internalizes within the host cell cytoplasm. Since nuclear and cytoplasmic [Ca2+] increases can induce different host cell responses, P. gingivalis-related [Ca2+] changes in these compartments were measured by digital fluorescent imaging microscopy. Non-deconvolved and deconvolved fura-2 images showed that P. gingivalis exposure caused human gingival epithelial cells cultured in physiologic [Ca2+] levels to undergo sustained oscillations of [Ca2+] in nuclear and cytoplasmic spaces. However, P. gingivalis invasion was not tightly correlated with intracellular [Ca2+] oscillations, since invasion could significantly precede, or even occur in the absence of, oscillations. [Ca2+] oscillations required a Ca2+ influx, which was completely inhibited by La3+ or 2-APB (2-aminoethoxydiphenyl borate), indicating Ca2+ entry was via a Ca(2+)-permeable channel. Ca2+ entry was likely not via a store-operated channel, since Ca2+ release from intracellular stores was not observed during cellular uptake of P. gingivalis. Hence, uptake of P. gingivalis in gingival epithelial cells induces oscillations in nuclear and cytoplasmic spaces by activating a Ca2+ influx through Ca2+ channels.
    Microbes and Infection 05/2004; 6(5):440-7. DOI:10.1016/j.micinf.2004.01.007 · 2.73 Impact Factor
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    Sahba Fatherazi, Carol M Belton, Kenneth T Izutsu
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    ABSTRACT: Calcium ion store-activated currents in undifferentiated human gingival keratinocytes were measured with the whole cell patch clamp and fura techniques. Thapsigargin or intracellular inositol 1,4,5-trisphosphate and BAPTA rapidly induced an early transient current with I(CRAC) (calcium release activated calcium ion current) characteristics, and several later, larger sustained currents that depended on the mode of store depletion. Thapsigargin activated two currents within minutes of I(CRAC) activation. The first was a nonspecific cation current, I(NSC). A second conducted Na+ and Cs+, and was partially inhibited by thapsigargin (INa1). Dialysis with inositol 1,4,5-trisphosphate and BAPTA induced a later current that also conducted Na+ and Cs+, but was inhibited by extracellular calcium ion (INa2), with properties consistent with an epithelial Na+ channel current in some cells, and a calcium ion-insensitive Na+ current (INa3). Comparison of thapsigargin-evoked current changes with fura-2/AM results from separate cells indicated that both the I(CRAC) and the later, larger calcium ion conducting currents contributed to changes in intracellular calcium ion concentration, and likely play important parts in calcium ion signaling in undifferentiated keratinocytes.
    Journal of Investigative Dermatology 08/2003; 121(1):120-31. DOI:10.1046/j.1523-1747.2003.12307.x · 6.37 Impact Factor
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    ABSTRACT: We have developed a fluorescence imaging technique using a DNA-binding dye to visualize, over time, the physical interactions between Porphyromonas gingivalis and human gingival epithelial cells in vitro. The results extend previous observations of P. gingivalis invasion of gingival epithelial cells based on indirect measurements. An intracellular location for P. gingivalis was established by optical sectioning of images in the z-plane. Kinetic analysis showed that P. gingivalis invasion of epithelial cells is a rapid and efficient process, reaching completion after 12 min. Imaging of infected monolayers revealed that over 90% of a population of gingival epithelial cells contained bacteria. Furthermore, only vital bacteria were capable of invasion, and intracellular bacteria congregated in the perinuclear region of the epithelial cells. P. gingivalis remained inside the epithelial cells over a 24 h period and induced rearrangement of the actin cytoskeleton along with alteration of the size and shape of the epithelial cells. These findings provide direct evidence that entry rates of P. gingivalis into gingival epithelial cells are high and rapid, and that internalized bacteria initially localize in a specific region of the epithelial cells.
    Cellular Microbiology 12/1999; 1(3):215-23. DOI:10.1046/j.1462-5822.1999.00022.x · 4.82 Impact Factor
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    ABSTRACT: Gsalpha has been reported to be present in rat parotid acinar secretory granule membrane (SGM) fractions. In the present study, we evaluated epitope orientation of Gsalpha on the secretory granule (SG) and the ability of Gs to modulate the Cl- conductance of isolated granules by measuring granule lysis. Gsalpha was found to be associated with the cytoplasmic face of the SGM. Aluminum fluroide (AlF4-, 20 microM Al3+ and 10 mM F-) significantly increased granule lysis and this effect was blocked by GDPbetaS. Cholera toxin (5 microg/ml) mimicked the effects of AlF4- on granule lysis, whereas pertussis toxin (0.5 microg/ml) was without effect. GTPgammaS, however, reduced granule lysis in a concentration-dependent manner. The orientation of Gsalpha on the SGM as well as the effects of AlF4- and cholera toxin on granule lysis lends support for a role of Gs in the exocytotic process.
    Biochemical and Biophysical Research Communications 10/1997; 238(2):638-42. DOI:10.1006/bbrc.1997.7354 · 2.28 Impact Factor
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    ABSTRACT: Porphyromonas gingivalis, a periodontal pathogen can invade primary cultures of gingival epithelial cells. This invasion was significantly inhibited (74-81%) by thapsigargin and 1,2-bis(2-aminophenoxy)ethane-N,N,N1,N1-tetraacetic acid, acetoxymethyl ester (BAPTA/AM), but not by EDTA or amiloride. Release of Ca2+ from an intracellular store and the subsequent increase in cytosolic [Ca2+] may, therefore, be involved in the invasion process, while Ca2+ influx is not. Moreover, cytosolic [Ca2+] was found to increase transiently in about 30% of gingival epithelial cells acutely exposed to P. gingivalis, but not in unexposed cells, or in cells exposed to noninvasive Escherichia coli. These findings indicate that P. gingivalis invasion of epithelial cells is correlated with activation of [Ca2+]-dependent host cell signaling systems.
    FEMS Microbiology Letters 12/1996; 144(2-3):145-50. · 2.72 Impact Factor
  • S Fatherazi, K T Izutsu, J R Martinez
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    ABSTRACT: Using the whole-cell patch-clamp technique, we investigated developmental changes in the expression of an acetylcholine- (Ach-) activated Cl- conductance in rat submandibular acinar cells. ACh induced an oscillatory inward current in cells isolated from animals older than 5 weeks, but not in animals less than 2-3 weeks of age. The current/voltage (I/V) relationship of the ACh-induced current was that of an outward rectifier, and the current was inhibited by intracellular BAPTA, a Ca2+ buffer, indicating the current was Ca2+ activated. The ACh-induced current was also blocked in the presence of DPC and SITS, two Cl- current inhibitors in other tissues. Ionomycin mimicked the effect of ACh but in a nonoscillatory fashion. The appearance of the ionomycin-induced currents was also age related, as the current was not observed to occur in animals less than 2-3 weeks old. Since both ACh and ionomycin significantly increase cytosolic [Ca2+] in the acinar cells of young animals, the correlation between the age dependence of the ACh-activated Cl- current and the ionomycin-activated Cl- current responses suggests that the lack of responsiveness observed in the young animals is due to the absence of Ca2+-activated Cl- channels, rather than to a deficiency of a cellular mediator.
    Pflügers Archiv - European Journal of Physiology 11/1996; 433(1-2):116-22. DOI:10.1007/s004240050256 · 3.07 Impact Factor
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    ABSTRACT: The relations between K+ channel and Cl- channel currents and mycoplasma infection status were studied longitudinally in HSG cells, a human submandibular gland cell line. The K+ channel currents were disrupted by the occurrence of mycoplasma infection: muscarinic activation of K+ channels and K+ channel expression as estimated by ionomycin- or hypotonically induced K+ current responses were all decreased. Similar decreases in ionomycin- and hypotonically induced responses were observed for Cl- channels, but only the latter decrease was statistically significant. Also, Cl- currents could be elicited more frequently than K+ currents (63% of cases versus 0%) in infected cells when tested by exposure to hypotonic media, indicating that mycoplasma infection affects K+ channels relatively more than Cl- channels. These changes occurred in the originally infected cells, were ameliorated when the infection was cleared with sparfloxacin, and recurred when the cells were reinfected. Such changes would be expected to result in hyposecretion of salivary fluid if they occurred in vivo.
    In Vitro Cellular & Developmental Biology - Animal 07/1996; 32(6):361-5. DOI:10.1007/BF02722962 · 1.00 Impact Factor
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    ABSTRACT: Porphyromonas gingivalis, a periodontal pathogen, can invade primary cultures of gingival epithelial cells. Optimal invasion occurred at a relatively low multiplicity of infection (i.e., 100) and demonstrated saturation at a higher multiplicity of infection. Following the lag phase, during which bacteria invaded poorly, invasion was independent of growth phase. P. gingivalis was capable of replicating within the epithelial cells. Invasion was an active process requiring both bacterial and epithelial cell energy production. Invasion was sensitive to inhibitors of microfilaments and microtubules, demonstrating that epithelial cell cytoskeletal rearrangements are involved in bacterial entry. P. gingivalis, but not epithelial cell, protein synthesis was necessary for invasion. Invasion within the epithelial cells was not blocked by inhibitors of protein kinase activity. Invasion was inhibited by protease inhibitors, suggesting that P. gingivalis proteases may be involved in the invasion process. Low-passage clinical isolates of P. gingivalis invaded with higher efficiency than the type strain. Serum inhibited invasion of the type strain but had no effect on the invasion of a clinical isolate. Invasion of gingival epithelial cells by P. gingivalis may contribute to the pathology of periodontal diseases.
    Infection and Immunity 11/1995; 63(10):3878-85. · 4.16 Impact Factor
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    ABSTRACT: Hypotonically induced changes in whole-cell currents and in cell volume were studied in the HSG cloned cell line using the whole-cell, patch clamp and Coulter counter techniques, respectively. Exposures to 10 to 50% hypotonic solutions induced dose-dependent increases in whole-cell conductances when measured using K+ and Cl- containing solutions. An outward current detected at 0 mV, corresponded to a K+ current which was transiently activated, (usually preceding activation of an inward current and had several characteristics in common with a Ca(2+)-activated K+ current we previously described in these cells. The hypotonically induced inward current had characteristics of a Cl- current. This current was inhibited by NPPB (5-nitro-2-(3-phenyl-propylamino)-benzoate) and SITS (4-acetamido-4'-isothiocyanostilbene), and its reversal potentials corresponded to the Cl- equilibrium potentials at high and low external Cl- concentrations. The induced current inactivated at voltages greater than +80 mV, and the I-V curve was outwardly rectifying. The current was unaffected by addition of BAPTA or removal of GTP from the patch pipette, but was inhibited by removal of ATP or by the presence of extracellular arachidonic acid, quinacrine, nordihydroguairetic acid, and cytochalasin D. Moreover, exposure of HSG cells to hypotonic media caused them to swell and then to undergo a regulatory volume decrease (RVD) response. Neither NPPB, SITS or quinine acting alone could inhibit RVD, but NPPB and quinine together totally inhibited RVD. These properties, plus the magnitudes of the induced currents, indicate that the hypotonically induced K+ and Cl- currents may underlie the RVD response. Cytochalasin D also blocked the RVD response, indicating that intact cytoskeletal F-actin may be required for activation of the present currents. Hence, our results indicate that hypotonic stress activates K+ and Cl- conductances in these cells, and that the activation pathway for the K+ conductance apparently involves [Ca2+], while the activation pathway for the Cl- conductance does not involve [Ca2+] nor lipoxygenase metabolism, but does require intact cytoskeletal F-actin.
    Journal of Membrane Biology 12/1994; 142(2):181-93. DOI:10.1007/BF00234940 · 2.17 Impact Factor
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    ABSTRACT: Whole cell currents were measured in HSG-PA cells (a proposed model for salivary gland duct cells) after muscarinic receptor activation or exposure to known signaling agents. Exposure to carbachol or oxotremorine M produced large and often oscillatory increases in outward current whose reversal potentials indicated a K current. The current was sensitive to extracellular atropine, charybdotoxin, and quinine, but not apamin, and to 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid in the pipette. The response was prolonged or increased by guanosine 5'-O-(3-thiotriphosphate) and mimicked by D-myo-inositol 1,4,5-trisphosphate (IP3) or heparin in the pipette and by extracellular Ca ionophores. Tetraethylammonium indirectly inhibited the response via the muscarinic receptor. Fura 2 in cell suspensions showed that muscarinic agonists increased cytosolic Ca ion concentration ([Ca2+]i) five- to sevenfold, and measurements with indo 1 in individual cells showed that the oscillatory changes in outward current were tightly correlated with parallel changes in [Ca2+]i. The results indicate that muscarinic receptor stimulation of HSG-PA cells activates Ca(2+)-activated K channels through a signaling pathway involving a G protein, IP3 production, and increased [Ca2+]i levels. These findings are similar to those in salivary gland acinar cells.
    The American journal of physiology 02/1994; 266(1 Pt 1):C58-66. · 3.28 Impact Factor
  • Kenneth T. Izutsu, Marie E. Cantino, Dale E. Johnson
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    ABSTRACT: Electron probe X-ray microanalysis (EPXMA) has now been successfully applied to several salivary gland preparations. This paper briefly reviews the principles underlying this technique and the specific sample preparation procedures which permit accurate measurement of elemental concentrations in the various intracellular spaces. Findings from salivary gland studies indicate that cytoplasmic and nuclear spaces of nonstimulated acinar cells have high concentrations of K and P, and low concentrations of Mg, Ca, and S; and that mature secretory granules have high concentrations of Ca and S, and relatively low concentrations of K and P. No consistent differences have been found between the elemental concentrations of mucous and serous secretory granules. In vivo and in vitro EPXMA studies of the elemental changes associated with secretory granule maturation indicate there are at least two stages in this process: an early stage during which granule S concentration increases in parallel with mass density as condensing vacuoles mature into secretory granules, and a late stage during which granule mass density and protein content increase with no further elemental concentration changes. Findings from other in vivo and in vitro studies indicate that secretory granule membranes are permeable to Na, K, and Cl ions because the granular concentrations of these elements are altered by electrochemical gradients. Recent EPXMA results indicate that cells stimulated with parasympathomimetic agonists have decreased K and Cl concentrations, and increased Na concentrations. Furthermore, the magnitude of these changes are quantitatively consistent with changes measured using radio-isotope equilibration and other techniques. In contrast, cells stimulated with the beta-adrenergic agonist, isoproterenol, have increased concentrations of Na and Cl, but unchanged K concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)
    Microscopy Research and Technique 01/1994; 27(1):71-9. DOI:10.1002/jemt.1070270106 · 1.17 Impact Factor

Publication Stats

2k Citations
258.86 Total Impact Points

Institutions

  • 1972–2014
    • University of Washington Seattle
      • • Department of Oral Health Sciences
      • • School of Dentistry
      • • Department of Pharmacology
      • • Department of Bioengineering
      • • Department of Pediatrics
      Seattle, Washington, United States
  • 1984
    • University of Illinois, Urbana-Champaign
      Urbana, Illinois, United States