K Watanabe

Kyushu University, Fukuoka-shi, Fukuoka-ken, Japan

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Publications (12)18.2 Total impact

  • [show abstract] [hide abstract]
    ABSTRACT: In order to examine whether FcepsilonRI-dependent degranulation of intestinal mast cells is required for expulsion of intestinal nematode Strongyloides ratti, CD45 exon6-deficient (CD45-/-) mice were inoculated with S. ratti. In CD45-/- mice, egg excretion in feces persisted for more than 30 days following S. ratti larvae inoculation, whereas in wild-type (CD45+/+) mice, the eggs completely disappeared by day 20 post-infection. The number of intestinal mucosal mast cells, which are known effector cells for the expulsion of S. ratti, was 75% lower in CD45-/- mice compared with that in CD45+/+ mice. Adoptive transfer of wild-type T cells from CD45+/+ mice into CD45-/- mice reduced the duration of S. ratti infection to comparable levels observed in CD45+/+ mice, with concomitant increases in intestinal mucosal mast cells. These results showed that CD45 is not involved in the effector function of intestinal mucosal mast cells against S. ratti infection. Since FcepsilonRI-dependent degranulation of mast cells is completely impaired in these CD45 knockout mice, we conclude that FcepsilonRI-dependent degranulation is not required in the protective function of intestinal mucosal mast cells against primary infection of S. ratti.
    Parasite (Paris, France) 09/2009; 16(3):209-14. · 1.12 Impact Factor
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    ABSTRACT: Among four ethnic groups in a lowland area of Nepal, the prevalences of abnormal haemoglobin, thalassaemia, glucose-6-phosphate-dehydrogenase (G6PD) deficiency, hereditary South-east Asian ovalocytosis (SAO) and Duffy blood-group antigen Fy/Fy were determined and related to each group's habitat. The group that has lived for many decades in a malaria-endemic lowland area, the Danuwar, was found to have a high prevalence of alpha+-thalassaemia (79.4%) and low prevalences of haemoglobin E and G6PD deficiency. Much lower prevalences of alpha+-thalassaemia were observed in the Newar (20.5%), Parbate (16.5%) and Tamang (8.8%), who, until the 1950s, all spent their hot-season nights in malaria-free areas at higher altitudes. No subjects with any other identified abnormal haemoglobin, beta-thalassaemia, SAO or Fy/Fy were detected.
    Annals of Tropical Medicine and Parasitology 04/2007; 101(2):113-22. · 1.31 Impact Factor
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    ABSTRACT: To determine the role of interleukin-5 (IL-5) and eosinophils in protection against Strongyloides ratti, mice treated with anti-IL-5 monoclonal antibody (mAb) were infected with S. ratti larvae. Strongyloides ratti egg numbers in faeces (EPG) in mAb treated mice were higher than those in control mice on days 6 and 7 after inoculation. The numbers of migrating worms in mAb treated mice 36 h after inoculation were higher than those observed in control mice. Intestinal worm numbers in mAb treated mice 5 days after inoculation were higher than those in control mice. These results show that eosinophils effectively protected the host against S. ratti infection by mainly the larval stage in primary infections. The involvement of eosinophils in protection against secondary infection was also examined. Before secondary infection, mice were treated with anti-IL-5 mAb and infected with S. ratti. Patent infections were not observed in either mAb treated or control Ab treated mice. The numbers of migrating worms in the head and lungs of mAb treated mice increased to 60% of that in primary infected mice. Intestinal worms were not found in mAb treated mice or in control mice after oral implantation of adult worms. Eosinophils were therefore mainly involved in protection against tissue migrating worms in secondary infections.
    Journal of Helminthology 01/2004; 77(4):355-61. · 1.16 Impact Factor
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    ABSTRACT: The effect of interleukin-4 (IL-4) on the induction of intestinal mast cells and cytokine profiles during Strongyloides ratti infection was studied using IL-4 knockout (IL-4 KO) mice. The antigen-specific proliferative response of mesenteric lymph node cells was not impaired in IL-4 KO mice. The number of intestinal mast cells induced in IL-4 KO mice during S. ratti infection was 2- to 3-fold lower than that observed in WT mice. Intestinal mastocytosis had disappeared in IL-4 KO mice by day 21 postinfection, when significant mastocytosis continued to be observed in WT mice. In mesenteric lymphnode of IL-4 KO, IL-3 production decreased and mice IFN-gamma production significantly increased as compared with those of WT mice. The numbers of eggs excreted per gram of feces (EPG) by IL-4 KO mice were greater than those excreted by WT mice on day 6 postinfection, but no difference was observed in the subsequent period. In conclusion, intestinal mast cells are induced during S. ratti infection in the absence of IL-4, and IL-4 is not essential for protection against intestinal adult worms of S. ratti.
    Parasitology Research 03/2001; 87(2):149-54. · 2.85 Impact Factor
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    ABSTRACT: To clarify the differences in the clinical features between idiopathic interstitial pneumonia (IIP) and interstitial pneumonia associated with collagen vascular diseases (CVD-IP). Symptoms, radiographic findings, pulmonary function, blood chemistry data including autoantibody, and bronchoalveolar lavage fluid (BALF) findings were compared using multiple logistic regression analysis. The subjects were 44 patients clinically diagnosed with IIP and 33 patients with CVD-IP. The clinical features related to IIP were as follows: male sex, advanced age, past history of hypertension, presence of cough, exertional dyspnea, digital clubbing, an increased level of gamma-globulin, decreased lung volume on chest X-ray, and typical type according to the criteria for IIP on chest X-ray. Increased levels of rheumatoid factor and total cell number in BALF were related to CVD-IP. These findings are considered to be useful to differentiate IIP and CVD-IP.
    Internal Medicine 04/2000; 39(3):213-9. · 0.97 Impact Factor
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    ABSTRACT: The involvement of granulocytes in the host early defense against the nematode, Strongyloides ratti, was studied. It was confirmed that granulocytes were effectively depleted for 4 days by anti-granulocyte monoclonal antibody (anti-Gr-1). To examine the involvement of granulocytes in the host defense against migrating larvae, 2,000 S. ratti infective larvae (L3) were inoculated subcutaneously 1 day after antibody treatment. The number of S. ratti eggs secreted in feces (EPG) was higher in the granulocyte-depleted group than in the control group. The number of migrating larvae also increased in the granulocyte-depleted group in accordance with the increase in EPG. Therefore granulocytes are crucial for the host early defense against migrating larvae of S. ratti. Next, the involvement of granulocytes in the intestinal early defense was examined. Mice were treated with the antibody on day 3 post-infection. On that day, almost all inoculated larvae reached the intestine and molted to become adults. EPG on day 5 post-infection was increased by the antibody treatment, but no effect was observed on intestinal worm numbers. The fecundity (EPG/worm number) of S. ratti adult worms in the granulocyte-depleted group was higher than that in the control group. Thus granulocytes are also involved in the intestinal early defense through suppressing fecundity of the adult worms. On the other hand, the depletion of granulocytes had no effect on the late adaptive response against S. ratti adult worms (e.g. number of intestinal mucosal mast cells, time of worm expulsion). These results suggest that granulocytes are mainly involved in the host early defense against parasites.
    Parasitology Research 04/2000; 86(3):188-93. · 2.85 Impact Factor
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    ABSTRACT: To obtain functional evidence for DCC as a tumour suppressor associated with endometrial cancer, the human DCC cDNA encoding a complete open reading frame (ORF) was transfected into highly tumorigenic human endometrial carcinoma cells, HHUA and Ishikawa in which DCC expression was completely deleted. Reconstituted expression of DCC in HHUA had little effect on in vitro growth, but suppressed tumour formation in mice completely. The clones from Ishikawa had abundant DCC expression similar to that in normal endometrium. Their growth in vitro was suppressed and showed apoptotic phenotype. Lower levels of DCC expression in the prolonged passaged clones did not induce apoptosis, but still had the potential to suppress tumorigenicity. These observations imply a role of DCC in regulation of normal endometrial cell growth, and categorize DCC as the tumour suppressor gene for endometrial cancer.
    British Journal of Cancer 02/2000; 82(2):459-66. · 5.08 Impact Factor
  • K Watanabe, S Hamano, K Noda, M Koga, I Tada
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    ABSTRACT: A sex-related difference in host susceptibility to Strongyloides ratti was previously known. Male mice were more susceptible to S. ratti infection and the difference was seen against migrating larvae under the regulation of testosterone. Against migrating larvae, macrophages were assumed to play important roles in host natural immunity. On the basis of these findings, to examine the effect of testosterone on macrophages we treated female mice with testosterone and/or carbon to block the function of macrophages. Mice were then infected with third-stage larvae of S. ratti. By counting of the migrating larvae in the cranial cavity at 36 h after infection the effect of each treatment was assayed. Testosterone treatment alone (Te) or carbon injection alone (Ca) effectively increased the worm recovery. Given together, Te and Ca (Te + Ca) significantly increased the worm recovery to levels almost equal to the sum of those achieved with Te and Ca. The serum testosterone concentration was elevated in mice that had undergone Te and Te + Ca at the time of worm recovery. Surprisingly, the serum testosterone concentration reached after Te + Ca was elevated more than that attained by Te. The same experiment with a half-dose of Te and Ca (Te half + Ca) resulted in the same testosterone concentration achieved with Te and resulted in a worm recovery almost equal to the sum of that achieved with Te and Ca. These results clearly showed that Te and Ca had an additive effect on the recovery of migrating S. ratti larvae. Testosterone had an effect after macrophages had been blocked. The relationship between testosterone and macrophage function during S. ratti infection is discussed.
    Parasitology Research 08/1999; 85(7):522-6. · 2.85 Impact Factor
  • Parasitology International - PARASITOL INT. 01/1998; 47:268-268.
  • Parasitology International - PARASITOL INT. 01/1998; 47:250-250.
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    ABSTRACT: Telomeres in somatic cells are progressively shortened with aging. We investigated the relationship between the telomere length and other factors which may affect the frequency of cell divisions, in peripheral blood cells. Shortening of telomeric repeats was correlated with aging (p < 0.0001), but not with white blood cell count, neutrophil count, and smoking habit. Not only the number of cell divisions, but also some other factors, such as upregulation level of telomerase activity concomitant with the cell division in hematopoietic progenitor cells, might affect the length of telomeric repeats in blood cells.
    The Japanese journal of human genetics 01/1997; 41(4):413-7.
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    ABSTRACT: The significance of postoperative irradiation for stage III lung cancer was analyzed in 30 patients. Radiation was given to 15 of the patients and the remaining 15 did not receive any radiation therapy following surgical intervention. A total dose of 40 to 70 Gy was given to the radiation group with a fraction dose of 2 Gy five times a week using cobalt 60 gamma-ray or linac 10 MV X-ray. There was no significant difference of survival time between these two groups. However, in analyzing modes of operation, radiation seemed to improve the survival rate in patients who underwent curative or relatively curative operations (P = 0.1), while the patients who underwent non-curative operations did not receive any benefit from the postoperative irradiation. Some reasons for the ineffectiveness in cases of non-curative operation are discussed.
    Radiation Medicine 2(2):143-7.