Biomedical subjects

H Watanabe

Publications and source records attributed to H Watanabe.

At least 415 records · Page 23Linked to original sources

PubMed2000

The differential effect of stress on natural killer T (NKT) and NK cell function.

When C57Bl/6 mice were exposed to restraint stress for 12 h or 24 h, lymphocytopenia was induced in the liver, spleen, and thymus. We examined which types of lymphocytes were sensitive or resistant to such stress by a immunofluorescence test. T cells of thymic origin were sensitive while NKT and NK cells were resistant. In contrast to the increase in the proportion of NK cells, NK activity of liver lymphocytes against YAC-1 targets decreased at 24 h after stress. On the other hand, their NKT cytotoxicity against syngeneic thymocytes increased in parallel with an increase in their proportion. In perforin -/- B6 mice and B6-gld/gld (Fas ligand-) mice, NK cells were found to mediate cytotoxicity through perforin while NKT cells mediated self-reactive cytotoxicity through Fas ligand. These results suggest that stress increases the proportion of both NK and NKT cells, but that NK cytotoxicity is suppressed while self-reactive NKT cytotoxicity is not, due to a diversity of their functional mechanisms.

Animals↗

PubMed2000

When can complete regression of low-grade gastric lymphoma of mucosa-associated lymphoid tissue be predicted after helicobacter pylori eradication?

AIMS: Recent studies suggest that primary low-grade gastric lymphomas of mucosa-associated lymphoid tissue (MALT) are cured in many cases between 1 and 18 months after H. pylori eradication. The aim of this study is to elucidate when complete regression (CR) of MALT lymphoma can be histologically predicted after H. pylori eradication. METHODS AND RESULTS: Twenty-one patients with low-grade gastric MALT lymphoma were treated with triple therapy (amoxicillin, clarythromycin and proton pump inhibitor) for 14 days. Subsequently, they were followed up by sequential endoscopy and biopsy (number of biopsy specimens for each endoscopy is 3-8, with an average of 4) from 91 to 657 days (average: 309 +/- 165 days). Eradication of H. pylori infection was achieved in all patients. Nine patients were free of lymphoma at 1 to 2 months after eradication and remained in CR at 163-657 days. Twelve patients showed residual lymphoma at 1 to 2 months after eradication. Five out of 12 patients revealed only one or two small foci of lymphoma-cell aggregation and showed a high incidence (80%) of CR at the latest biopsy (135-434 days, average 276 +/- 115 days after eradication), while seven patients showed diffuse remains of lymphoma cells and indicated CR in only one case (14%) at 362 days, partial regression in five cases at 130-431 days (average 227 +/- 114 days), and no change in one case at 91 days after eradication. CONCLUSIONS: : These results suggest that CR of low-grade MALT lymphoma can be predicted at 1 to 2 months after eradication therapy by checking histological changes of MALT lymphoma cells.

Adult↗

PubMed2000

Disparate effect of beige mutation on cytotoxic function between natural killer and natural killer T cells.

Beige mice lack natural killer (NK) cytotoxicity, although NK cells are normally present. In recent studies, NK T cells have been newly identified. We therefore examined the number and function of NK T cells in beige mice. The number of NK T cells was at a normal level in the liver of beige mice. NK cytotoxicity was decreased in the liver of these mice, whereas NK T cytotoxicity was intact. When immunochemical staining for perforin was conducted, the majority of NK cells and the minority of NK T cells in beige mice carried a giant granule, containing perforin, in the cytoplasm. In the case of control B6 mice, the majority of NK cells and the minority of NK T cells had multiple, dispersed granules containing perforin. These results suggest that NK T cytotoxicity is unaffected by the beige mutation, owing to their cytotoxicity being mediated without the secretion system of perforin.

Animals↗

PubMed2000

Resistance of extrathymic T cells to stress and the role of endogenous glucocorticoids in stress associated immunosuppression.

When mice were exposed to restraint stress for 12 or 24 h, severe lymphopenia was induced in all immune system organs, including the liver and the thymus. However, in adrenalectomized mice, this response was completely absent. Phenotypic characterization revealed that interleukin (IL)-2Rbeta+CD3int cells (i.e. extrathymic T cells) with CD4+ phenotype and the NK1.1+ subset of CD3int cells (i.e. NKT cells) in the liver as well as the mature conventional T cells in the thymus were resistant to such stress. In adrenalectomized mice, there was no significant change in the distribution of lymphocyte subsets in all tested organs before stress. Interestingly, the number of lymphocytes in the liver and spleen and the proportion of NKT cells in the liver rather increased after stress in these adrenalectomized mice. Therefore, endogenous steroid hormones were indicated to be important in the induction of immunosuppressive states after stress. Among stress associated cytokines, the secretion of tumour necrosis factor (TNF)-alpha was completely suppressed while that of IL-6 was partially suppressed in adrenalectomized mice. These results suggest that endogenous steroid hormones are important for the induction of the stress associated immunosuppression and that NKT cells are resistant to stress, namely, resistant to exposure to endogenous steroid hormones.

Adrenalectomy↗

PubMed2000

FRL1 is required for petal and sepal development in Arabidopsis.

A novel flower mutant, frl1 (frill 1) was isolated in Arabidopsis thaliana. The frl1 mutant has serrated petals and sepals but the other floral and vegetative organs appear to be normal. To analyse the role of the FRL1 gene, morphological, cytological and double mutant analyses were carried out. The frl1 flower had broader petals and sepals as compared with the wild-type. The distal region of frl1 petals contained fewer epidermal cells but their size was variable and generally larger than that in the wild-type. However, no significant difference was found in the basal region. Observations of the early petal development revealed that the morphology of the developing frl1 petal was normal until the middle of stage 9, but the frl1 phenotype became apparent in stages later than 10. Furthermore, larger nuclei with varied sizes were observed in the distal region of frl1 petals, but not in this region in wild-type petals. This strongly suggests that abnormal endo-reduplication had occurred. These observations indicate that the frl1 mutation affects the number of cell divisions and the subsequent cell expansion during the late stage of petal lamina formation, and that FRL1 might be maintaining the mitotic state or suppressing the transition to the endo-reduplication cycle. Double mutants with the homeotic mutants apetala3-1 and agamous showed additive phenotypes. Ectopic petals in the third whorl of fr11 ag flowers were serrated, indicating that the FRL1 gene acts in petal and sepal development in an organ-specific manner.

Arabidopsis↗

PubMed2000

Spontaneous regression of hepatocellular carcinoma and review of literature.

A 68-year-old man presented with multiple hepatocellular carcinoma, which was considered to be unresectable at the first admission in January 1994. Pathological diagnosis was made by biopsy of the one lesion among them. From January 1994 to December 1997, 10 transarterial chemoembolizations and six percutaneous ethanol injection therapies were performed on the tumours in the cirrhotic liver. In February 1998 the tumour situated in the right lobe began to increase in size. The maximum tumour diameter was 6.3 cm measured by computed tomography (CT). In the beginning of May 1998 moderate ascites was present and mild hepatic encephalopathy was noticed. The patient was in the terminal stage of hepatocellular carcinoma and no further treatment was possible at that time. However, serum alpha-fetoprotein and protein induced by vitamin K absence or antagonist II dramatically decreased in June 1998. The CT scan also showed that the tumour had completely regressed without specific treatment. In February 1999 a new biopsy-proven hepatocellular carcinoma, 2 cm in diameter, developed in the lateral segment of the liver. It was well treated by percutaneous ethanol injection therapy. The patient was alive in good condition without any symptoms or tumour recurrence in June 1999. It was concluded that a rare case of spontaneous regression of hepatocellular carcinoma had occurred.

Aged↗

PubMed2000

Enhanced tumorigenicity of insulinoma by X-irradiation of the gastric regions in Sprague-Dawley male rats.

BACKGROUND AND AIMS: There has been no suitable animal model for human insulinoma because incidence of pancreatic tumours induced by whole-body irradiation or chemicals has been very low. The purpose of this study was to establish an experimental model with a high incidence of insulinoma. The induction of islet cell tumour by X-irradiation was investigated. METHODS: Forty Sprague-Dawley male rats were used in this study. Twenty-eight rats were irradiated with two 10-Gy doses to the gastric region at a 3-day interval, and 12 rats not subjected to X-irradiation served as a control group. The rats were killed 16 months after the first irradiation. Expression of insulin mRNA and protein was examined by northern blot analysis and immunohistochemistry, respectively. Rat serum insulin and glucose levels were measured using enzyme-linked immunosorbent assay. RESULTS: Tumour incidence was 89.3% (25/28) in X-ray group and 8.3% (1/12) in the control group (P < 0.05). Pancreatic tumours, which appeared in all 25 rats with tumours, showed the highest incidence of all neoplasms detected. Tumour cells showed strong immunoreactivity for insulin in 20 of 25 pancreatic tumours (80%). Expression of insulin mRNA was confirmed by northern blot analysis. Furthermore, rats with pancreatic tumours had lower serum glucose levels and higher insulin levels than the control rats. CONCLUSION: X-irradiated SD rats may be considered a suitable model for insulinoma because of their high tumorigenicity.

Animals↗

PubMed2000

Declining of memory functions of normal elderly persons.

Two studies examined the declining of memory functions in normal elderly persons using the Yokota memory test (YMT), which includes 15 items concerning verbal and non-verbal memory functions. In the first study, 552 subjects over 40 years of age in five age groups were examined. Factor analysis revealed that YMT consisted of two factors pertaining to short-term/working memory, and two factors pertaining to long-term memory. It is suggested that the former was more affected than the latter, with aging. In the second study, YMT was examined in relation to the revised version of Hasegawa dementia scale (HDS-R), which was the most popular intelligence scale for the elderly in Japan. As a result, memory functions differentially declined with the decreasing score of HDS-R, which suggests that memory functions differentially declined with progressive risk of dementia.

Adult↗

PubMed2000

Effects of subtotal resection of the fundus on development of intestinal metaplasia induced by X-ray irradiation in Donryu rats.

Eight-week-old male Crj:Donryu rats underwent subtotal resection of the fundus and X-ray irradiation. Six months later the animals were autopsied and examined for intestinal metaplasia. The numbers of alkaline phosphatase-positive foci with the two treatments in combination were significantly increased, compared to the operation alone and non-treatment groups. Histologically assessed intestinal metaplasia was also increased in the combined treatment group. In conclusion, subtotal resection of the fundus combined with X-ray irradiation is an effective induction protocol for intestinal metaplasia.

Alkaline Phosphatase↗

PubMed2000

A comparative clinical study of pneumonia by penicillin-resistant and -sensitive Streptococcus pneumoniae in a community hospital.

OBJECTIVE: This study aimed to determine the clinical difference of pneumonia between penicillin-resistant and penicillin-sensitive Streptococcus pneumoniae. METHODOLOGY: Forty-nine cases in 46 patients of pneumococcal pneumonia were studied from December 1992 to May 1997. There were 24 cases (in 22 patients) of penicillin-resistant pneumococci (PRSP) pneumonia which were compared with 25 cases (in 24 patients) with penicillin-sensitive pneumococci (PSSP). RESULTS: Both the mean age and the underlying disease states did not differ between the two groups. However, hospital-acquired pneumonia and previous use of antibiotics were observed in eight (33.3%) and 12 (50.0%) patients in PRSP compared with three (12.0%) and two (8.0%) in PSSP, respectively. The clinical efficacy rate and bacteriological eradication rates were 87.5 and 87.5% in PRSP compared with 87.5 and 87.0% in PSSP, respectively. Minimum inhibitory concentration (MIC) of antibiotics against 30 pneumococcal isolates was examined, and 10 strains ranged from 0.10-0.78 microg/mL and five strains were more than 1.56 microg/mL against penicillin G, while the MIC showed higher resistance to other antibiotics except for the carbapenems. Serotyping of the isolates by antiserum revealed differences in the predominant types PRSP (19F) and PSSP (6A,9V) [corrected]. CONCLUSIONS: We must care for not only community-acquired infection but also nosocomial transmission of PRSP pneumonia. Most patients with infections due to PRSP tended to have a milder illness with a good outcome (no patient died). As such it appears that empiric therapy for pneumococcal pneumonia does not require modification from what is recommended at present. However, in patients with infection due to highly resistant strains, and who are not responding to conventional therapy should have their treatment modified according to subsequent susceptibility testing.

Anti-Bacterial Agents↗

PubMed2000

Psittacosis with increased gammadelta T cells in bronchoalveolar lavage fluid.

Experience with two cases of psittacosis is described here in which the number of gammadelta T cell receptor-positive T lymphocytes (gammadelta T cell) in the bronchoalveolar lavage fluid was markedly increased (25.1 and 66.9%) and CD8+ T cells were also increased with reversal of the CD4/CD8 ratio. These values improved to the normal range along with recovery of their radiographical findings. The present findings suggest that gammadelta T cells may play an important role in protection from lung injury caused by Chlamydia psittaci infection.

Adult↗

PubMed2000

Histochemical study of angiogenesis in basaloid squamous carcinoma of the esophagus.

Angiogenesis of esophageal basaloid squamous carcinoma (BSC) was studied immunohistochemically and compared with that of squamous cell carcinoma (SCC). In tissues taken from six patients with esophageal BSC and 35 with esophageal SCC, angiogenesis was evaluated by measuring microvessel density (MVD), defined as the microvessel count determined using factor VIII-related antigen immunostaining, and by measuring immunoreactivity of vascular endothelial growth factor (VEGF) and thymidine phosphorylase (dThdPase). Three of the six patients with BSC had distant metastases. There was no difference of MVD between BSC and SCC (22.0 +/- 4.6 vs. 27.6 +/- 9.4). VEGF expression tended to be more frequently observed in BSC than in SCC (100% vs. 60.0%; p = 0.066). Strong expression of VEGF was detected in three BSC with distant metastases; however, there was no difference in the rate of strong VEGF expression between BSC and SCC. The MVD in the cases of BSC with strong VEGF expression, i.e. in the cases with distant metastases, was higher than that in the cases of BSC with weak VEGF expression (p=0.049). There was no difference in dThdPase expression of the cancer cells between BSC and SCC (50.0% vs. 54.3%), whereas the infiltrating stromal cells of all the BSC expressed dThdPase. Strong dThdPase expression in the cancer cells or in the infiltrating stromal cells was observed in two and three BSC, respectively. However, there were no differences in the rate of cancer cells or stromal cells with strong dThdPase expression between BSC and SCC. In one BSC with high MVD and distant metastases, VEGF and dThdPase were both strongly expressed. The vascularity of esophageal BSC was not different from that of SCC. VEGF may participate in angiogenesis of esophageal BSC and may influence the rate of metastasis in esophageal BSC patients. dThdPase may play a partial rule in angiogenesis and metastasis in some cases of BSC.

Aged↗

PubMed2000

Elimination of atretic follicles from the mouse ovary: a TEM and immunohistochemical study in mice.

We examined numerous ovarian follicles from 32-35 d virgin mice by transmission electron microscopy and light microscopic immunohistochemistry. No macrophages were seen, but various stages of apoptotic granulosa cells were encountered. Presumably a granulosa cell or its debris in an advanced stage of apoptosis was destined to be phagocytosed by adjacent normal-looking granulosa cells. Other granulosa cells of normal appearance were seen in the region of the zona pellucida in contact with and apparently phagocytosing atrophic oocytes. Such granulosa cells were characterised by the presence of gap junctions with other cells and frequently contained annular gap junctions in the cytoplasm. To confirm the lack of involvement of macrophages in the process of follicular atresia and elimination, specially prepared ovarian sections were incubated with antimouse macrophage monoclonal antibodies (F4/80, Mac-1, Mac-2). None of the follicles examined showed positive immunoreactivity with these antibodies. Atretic follicles may shrink and eventually disappear from the ovary as a result of repeated apoptosis and phagocytosis by granulosa cells. There is no evidence for the presence or involvement of macrophages in the atretic follicles, at least in prereproductive mice as examined.

Animals↗

PubMed2000

Disruption of the epilepsy KCNQ2 gene results in neural hyperexcitability.

Benign familial neonatal convulsion (BFNC) is a common idiopathic epilepsy with autosomal dominant inheritance. Recently, two novel voltage-dependent potassium channel genes, KCNQ2 and KCNQ3, were identified by positional cloning as being responsible for BFNC. Heterotetramers of the products of these genes form M-channels and regulate the threshold of electrical excitability of neurons. We disrupted the mouse KCNQ2 gene via gene targeting to study the relationship between KCNQ2 and epilepsy. Homozygous pups (KCNQ2 -/-) died within a few hours after birth owing to pulmonary atelectasis that was not due to the status of epileptic seizures, although their development was morphologically normal. Heterozygous mice had decreased expression of KCNQ2 and showed hypersensitivity to pentylenetetrazole, an inducer of seizure. These data indicate that the decreased expression of KCNQ2 might cause a hyperexcitability of the CNS, which accounts for the mechanism of BFNC.

Animals↗

PubMed2000

Changes in cardiopulmonary parameters during upper gastrointestinal endoscopy in patients with heart disease: towards safer endoscopy.

BACKGROUND AND STUDY AIMS: Gastrointestinal endoscopy is an invasive examination. The aims of this study were to elucidate the effects and risks of upper gastrointestinal endoscopy with regard to cardiopulmonary functions in patients with heart disease, and to establish safety guidelines for use during endoscopy in this particular group of patients. PATIENTS AND METHODS: The patients involved were 53 inpatients in whom upper gastrointestinal endoscopy was carried out before cardiac surgery. Their cardiac functions had been evaluated previously. Electrocardiography with two leads (II, V5) was used, and blood pressure and peripheral oxygen saturation (SpO2) were monitored throughout the procedure. The relationship between the changes in cardiopulmonary parameters during endoscopy and the cardiac functions was analyzed. RESULTS: Heart rate increased immediately after insertion of the endoscope (P < 0.01). There was a significantly higher incidence of ventricular and supraventricular extrasystoles during observation of the second portion of the duodenum (P < 0.05). A lower cardiac index (P < 0.05) and a higher New York Heart Association (NYHA) functional classification (P < 0.05) were found in patients with oxygen desaturation than in patients without it. Two patients with severe coronary artery lesions showed marked ST-T depression, and these ischemic changes were thought to be due to increase in cardiac work during endoscopy. CONCLUSIONS: Upper gastrointestinal endoscopy has many adverse effects on cardiopulmonary functions in patients with heart disease. In our study, the clinical value of very close monitoring and administration of oxygen for patients with heart disease was confirmed by objective data.

Aged↗

PubMed2000

Value of laparoscopic microwave coagulation therapy for hepatocellular carcinoma in relation to tumor size and location.

BACKGROUND AND STUDY AIMS: The indications for laparoscopic microwave coagulation therapy (LMCT) for hepatocellular carcinoma (HCC) have not yet been adequately evaluated. This study investigated the value of LMCT in the treatment of HCC. PATIENTS AND METHODS: Forty-three patients with liver cirrhosis (including five patients in Child Pugh grade C), with 56 HCC lesions, were enrolled in the study. When dynamic computed tomography (CT) showed a loss in HCC enhancement characteristics and a low concentration area after LMCT, a lesion was judged to have undergone complete necrosis. RESULTS: The rate of complete necrosis for lesions measuring 40 mm or less was significantly higher (P<0.01) than for those measuring 41 mm or more. The rate of complete necrosis for lesions located on the liver surface, excluding those located close to the gallbladder or in contact with the diaphragm, was also significantly higher (P<0.01) than for those situated deep within the liver. The outcome for lesions of 40 mm or less was favorable. Intra-abdominal hemorrhage occurred in two patients, pneumothorax in three, and hepatic infarction in one, all associated with LMCT. However, these patients did not suffer any sequelae of clinical significance. CONCLUSIONS: This study suggests that there is a strong indication for LMCT for HCCs measuring 40 mm or less in diameter and those located on the liver surface even if they are as large as 50 mm, but not for those located close to the gallbladder or in contact with the diaphragm. LMCT appears to be applicable in patients with impaired liver function.

Aged↗

PubMed2000

Cardiac strangulation in a neonatal case: a rare complication of permanent epicardial pacemaker leads.

A newborn female underwent pacemaker implantation with epicardial pacing leads for the treatment of bradycardia caused by congenital atrioventricular block. At 10 months after pacemaker implantation, she was admitted with congestive heart failure. The epicardial leads were seen to encircle the heart, and myocardial ischemia was suggested. During cardiac catheterization she collapsed: emergency operation was performed, but she died on postoperative day 6.

Bradycardia↗

PubMed2000

Significance of immunohistochemically demonstrated micrometastases to lymph nodes in esophageal cancer with histologically negative nodes.

BACKGROUND: We examined the prevalence, patterns, and clinical significance of nodal micrometastases in patients with esophageal cancer. METHODS: Cervical, mediastinal, and abdominal lymph nodes systematically removed from 37 patients without conventional histologic evidence of lymph node metastasis from esophageal squamous cell carcinoma were immunohistochemically examined to detect cells that were stained for cytokeratins by the monoclonal antibody cocktail AE1/AE3. Postoperative care and survival were compared in cases with and without such micrometastases. RESULTS: Nodal micrometastases were found in 14 of 37 patients (38%). Among these patients, 9, 7, and 4 had micrometastases to abdominal, mediastinal, and cervical lymph nodes, respectively. Postoperative tumor recurrence was significantly more frequent in patients with micrometastases (50%) than in those without (9%, P = .008). Overall and relapse-free survival in the former group was significantly worse than in the latter group (P = .042 and P = .002, respectively). Nodal micrometastases had an independent prognostic importance for relapse-free survival as determined by multivariate analysis. CONCLUSIONS: Metastatic tumor cells are frequently present in lymph nodes, even in patients without histologic evidence of nodal metastasis from esophageal cancer. Nodal micrometastases indicates a poorer prognosis after a curative esophagectomy procedure in histologically node-negative cases.

Aged↗