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Biomedical subjects

T Komatsu

Publications and source records attributed to T Komatsu.

At least 145 records · Page 8Linked to original sources
PubMed1997

Seasonal changes in the immunolocalization of steroidogenic enzymes in the testes of the Japanese black bear (Ursus thibetanus japonicus).

Seasonal changes in sites of immunostaining of steroidogenic enzymes were examined in testes of the Japanese black bear, Ursus thibetanus japonicus. In addition, serum concentrations of testosterone and estradiol-17beta were investigated by radioimmunoassay, and the seasonal changes were compared with the results of immunostaining. On the basis of morphological observations of spermatogenic activity, the reproductive cycle was divided into five periods: an active period in May and June; a degenerative period in November; a resting period in January; an early-resumptive period in March; and a late-resumptive period in April. Serum concentrations of testosterone differed with season accompanied by differences in spermatogenic activity, with baseline levels in November and January, increasing levels in March and April, and high levels in May, and April and June of the next year. Immunoreactivities specific for cholesterol side-chain cleaving cytochrome P450, 17alpha-hydroxylase cytochrome P450 and 30-hydroxysteroid dehydrogenase (3beta HSD) were observed in Leydig cells throughout the year. Only the percentages of Leydig cells immunopositive for 3beta HSD exhibited seasonal differences that correlated with serum concentrations of testosterone. Aromatase cytochrome P450 (P450arom) was immunolocalized in Leydig and Sertoli cells throughout the year, in spermatids in May, and April and June of the next year and in myoid cells in January and March. The percentages of Leydig cells immunopositive for this enzyme increased in May, and January, March and June of the next year. On the other hand, no pattern of seasonal change in serum estradiol-17beta concentration was observed. These results suggest that 3beta HSD is a key enzyme in the regulation of the testosterone production in Leydig cells. Furthermore, estrogen derived from Leydig and myoid cells seems to play a role in the regulation of Leydig cells by negative feedback as a paracrine and/or autocrine mediator.

3-Hydroxysteroid Dehydrogenases↗
PubMed1997

Localization of neuropeptides in endocrine cells of the chicken thymus.

Interactions between endocrine cells and epithelial cells, mediated by neurotensin, have been proposed in the chicken thymus. In this study, other neuropeptide candidates acting as mediators in the chicken thymus were examined immunohistochemically. Endocrine cells being oval, elongated or triangular in shape were immunoreactive with antibodies against methionine-enkephalin, neuropeptide Y, substance P, and vasoactive intestinal peptide. These findings suggest that 4 neuropeptides may be involved in cell-to-cell interactions in the chicken thymus.

Animals↗
PubMed1997

Seasonal changes in subcellular structures of Leydig and Sertoli cells in the Japanese black bear, Ursus thibetanus japonicus.

The fine structure of Leydig and Sertoli cells in Japanese black bears, Ursus thibetanus japonicus, was studied at different stages of reproductive activity in different seasons. Structures of Leydig cells in the testes that were spermatogenically active (May and June), inactive (November and January), and resumptive (March and April) were found to be different. The nucleus and smooth endoplasmic reticulum in Leydig cells had regressed when observed in November and January, and began to develop in March and April. Lipid droplets were numerous in Leydig cells in November and January, but few in March and April. These seasonal variations in the subcellular structures of Leydig cells corresponded to those in the steroidogenic activity of the cells. In Sertoli cells, changes in mitochondria and lipid inclusions with the seasons were detected, but the nuclei and other organelles, including the rough endoplasmic reticulum, did not change throughout the year. Lipid inclusions of both electron-dense and electron-lucent types in Sertoli cells were numerous in November and few in January. This change was reversely proportional to the number of degenerating cell masses in the luminal space, indicating that most of these lipid inclusions might be the end products of germ cells phagocytosed by the Sertoli cells. The results suggest that the seasonal changes in the morphology of Leydig cells are closely associated with their spermatogenic activity

Animals↗
PubMed1997

Immunohistochemical localization of basic fibroblast growth factor (bFGF) during folliculogenesis in the human ovary.

Basic fibroblast growth factor (bFGF) has been suggested to be one of the intraovarian regulators of ovarian folliculogenesis, but its localization in the human ovary remains to be determined. We examined the immunohistochemical reactivity for bFGF in the course of follicular development and corpora lutea formation in the human ovary. Pregranulosa cells in the primordial follicle were negative, but at the preantral stage both granulosa and theca cells showed weakly positive immunostaining for bFGF. In the antral follicles, both granulosa and theca interna cells showed stronger staining for bFGF with the increase in follicular diameter. In atretic follicles at various stages, granulosa cells were negative or weakly positive for bFGF, whereas luteinized theca cells showed strong immunoreactivity. In the corpora lutea during the early luteal phase, granulosa lutein cells were strongly positive for bFGF but in the late luteal phase became immunonegative. On the other hand, bFGF staining in theca lutein cells was strong throughout the course of corpora lutea formation and regression. These findings suggest that bFGF is localized not only in granulosa cells but also in theca cells, and in the latter, bFGF immunoreactivity is associated with luteinization.

Adult↗
PubMed1997

[Allopurinol induced pancytopenia in a patient with myeloproliferative disorder].

We reported a rare case of pancytopenia caused by allopurinol. A 61-year-old man was first admitted in May 1993, because of thrombocytosis. He had suffered from chronic glomerulonephritis. He was administered allopurinol for hyperuricemia from March 1993. On first admission the laboratory findings revealed leukocytosis (10,100/microliter) and thrombocytosis (971 x 10(3)/microliter) in the peripheral blood. Myelofibrosis was strongly suspected due to increased number of MgK and reticular fiber in the bone marrow. Two months later, he readmitted due to pancytopenia (WBC 1,300/microliter, Hb 6.2g/dl, Plt 10 x 10(3)/microliter). His bone marrow showed markedly hypocellular. Because we suspected that pancytopenia was induced by allopurinol, we discontinued allopurinol and administered oxymetholone, G-CSF, and EPO, WBC, RBC, and platelet count had been recovered about one and half months later. In vitro co-culture indicated that CFU-G, E, and Meg in the bone marrow cells after recovery from pancytopenia were markedly suppressed in the presence of patient's serum and oxipurinol. Pancytopenia due to allopurinol was reported to be rare, and some authors showed that it will sometimes be fatal. Because pancytopenia of this case had been recovered in a relatively short time with cytokine therapy, it was thought to be effective for pancytopenia due to drug like this case.

Allopurinol↗
PubMed1997

[Trial of radiation and cisplatin, carboplatin combination chemotherapy for advanced cancer (W-platinum chemoradiotherapy].

Cisplatin was reported to be an effective radiation sensitizing agent. The effect was also reported to depend on dose intensity. But the incidence of complication was demonstrated in the relationship with the dose escalation curve of anti-cancer agent. The major side effect of CDDP was occasionally serious, as in renal toxicity or bone marrow suppression. W-Platinum is the trial of concurrent chemoradiotherapy. Cisplatin and its derivative, Carboplatin, were selected as effective radiation sensitizing agents and to obtain high-dose intensity and additive cytotoxicities by interaction between the two drugs. Concomitant administration of two platinum anti-cancer agents has the advantage of reduction of side effects compared with administration of single anti-cancer agents to the same degree. The first case was a recurrence of epipharyngeal cancer after 3 courses of chemotherapy, including CDDP or CBDCA. This case was suspected to be cancer-resistant to CDDP. The second case was post-operative residual lung cancer. The pre-operative diagnosis was stage III A. A poor prognosis was expected. This case was disease-free and alive for 1 year after W-Platinum administration. The most frequent complication was bone marrow suppression. Patients were rescued from bone marrow suppression with administration of G-CSF. Renal toxicity could be suppressed with sufficient hydration.

Adenocarcinoma↗
PubMed1997

[Placental transfer of vecuronium administered with priming principle regimen in patients undergoing cesarean section].

Eight women having cesarean section under general anesthesia received vecuronium (VCB) 0.01 mg.kg-1 as a priming dose, followed 180 s later by 0.11 mg.kg-1 as an intubation dose. Subsequently, VCB concentrations of umbilical venous and maternal arterial blood at delivery were assayed. The time from the injection of intubation dose to delivery was 283 +/- 55 (mean +/- SD) s. Umbilical and maternal VCB concentrations at delivery were 79.4 +/-36.1 1ng.ml-1 (UV) and 1258.3 +/- 464.1 ng.ml-1 (MA). respectively. Thus, the umbilical venous to maternal arterial VCB concentration ratio (UV.MA-1) was 0.07 +/- 0.02. One-min and 5-min Apgar scores were 8-9 and 9-10, respectively. Judging from previous reports concerning VCB administration during cesarean section, total of VCB 0.12 mg.kg-1 may be an overdose. We concluded therefore that of total VCB 0.10 mg.kg-1 seems to be an appropriate dose for cesarean section.

Adult↗
PubMed1997

[Continuous epidural morphine for postoperative pain relief after spinal surgery--use of an epidural catheter placed at the time of surgery].

Postoperative analgesia by continuous epidural morphine infusion after spinal surgery was investigated in a retrospective study. An epidural catheter was placed by surgeons at the time of surgery. Postoperative pain was less intense and use of analgesics and sedative was less frequent in patients with continuous epidural morphine (n = 41) as compared with patients without continuous epidural morphine (n = 41). Among the patients with continuous epidural morphine, postoperative pain in patients (n = 16) with the dura opened or dural rent during surgery was less intense and the uses of analgesics and sedative was less frequent as compared with patients (n = 25) without the dural rent. There were no severe complications except for respiratory depression in a patient with chronic obstructive pulmonary disease. Our study demonstrated the ease of insertion of an epidural catheter at the time of surgery and the good quality of epidural analgesia after spinal surgery.

Adult↗
PubMed1996

Activation of type III nitric oxide synthase in astrocytes following a neurotropic viral infection.

Type III nitric oxide synthase (type III NOS), also known as endothelial cell nitric oxide synthase (eNOS or ecNOS or NOS-3), is a constitutively expressed, calcium- and calmodulin-dependent, isoform of NOS. Its expression has been localized to endothelial cells and a subset of neurons in the brain. We report here that resident astrocytes of the central nervous system (CNS) of mice express type III NOS. Following an experimental neurotropic viral infection, the expression of type III NOS on reactive astrocytes increases substantially, predominantly in virally infected regions of the brain. This upregulation of type III NOS expression is also evident following cytokine treatment in vitro. The intraperitoneal (i.p.) administration of IL-12, a potent activator of IFN-gamma and TNF-alpha production, results in a substantial increase in type III NOS immunoreactivity in astrocytes. Cytokine-mediated activation of type III NOS is observed in vitro following exposure of a C6 glioma cells, which constitutively express type III NOS, to IL-12, IFN-gamma, and TNF-alpha treatment. We conclude that astrocytes of the murine CNS express type III NOS, which may be positively regulated by a number of cytokines following viral infection. Type III NOS expression by astrocytes represents a novel source of nitric oxide in the brain. It may be important in regulating perfusion and maintaining the blood-brain barrier. Given the intimate association of astrocytes with endothelial cells and neurons, increased activity of type III NOS following viral infection may be beneficial in inhibition of viral infection in neighboring cells.

Animals↗
PubMed1996

Expression of heat shock proteins HSP70 and HSP90 in endometrial carcinomas. Correlation with clinicopathology, sex steroid receptor status, and p53 protein expression.

BACKGROUND: It has been suggested that heat shock proteins HSP70 and HSP90 are involved in the functional modulation of sex steroid receptors and are expressed in normal endometrium. However, little is known about the expression of HSP70 and HSP90 in endometrial carcinomas. METHODS: The immunohistochemical reactivity of monoclonal antibodies against HSP70 and HSP90 was examined in 42 endometrial carcinomas, and the presence or absence of correlation with the clinicopathologic features, sex steroid receptor status, and p53 protein expression was analyzed. RESULTS: Expression of HSP70 was found in 52% of endometrial carcinomas and was correlated with nonendometrioid histology (P < 0.05), a poorly differentiated state (P < 0.01), p53 protein expression (P < 0.01), and absence of sex steroid receptors (P < 0.001) in the tumor. By contrast, strong expression of HSP90 was observed in 29% of endometrial carcinomas, and occurred more frequently in well-differentiated carcinomas that were positive for sex steroid receptors. CONCLUSIONS: Both HSP70 and HSP90 are significantly correlated with the histology and the sex steroid receptor status of endometrial carcinomas. Expression of HSP70 may be associated with a loss of sex steroid receptors in either nonendometrioid or poorly differentiated carcinoma of the endometrium, which frequently exhibits p53 protein expression. Conversely, strong expression of HSP90 may indicate high levels of sex steroid receptors in the tumor cells.

Adult↗
PubMed1996

Malignant plexiform tumor of the uterus: an unusual variant of epithelioid leiomyosarcoma.

A 46-year-old woman with the complaint of hypermenorrhea underwent hysterectomy for a presumed uterine myoma. The solid tumor in the myometrium was gray in color, was 4 cm in diameter, and showed hemorrhage and necrosis. Histologically, the tumor consisted of round or polygonal cells arranged in cords and nests, and its histological features closely resembled those of plexiform tumor which has been reported as a benign, epithelioid smooth muscle tumor of the uterus. In the tumor in our patient, however, mild nuclear atypia and two to three mitoses/10 high-power fields were present. Two months after the hysterectomy, the patient was found to have metastatic foci in the lumbar vertebrae and iliac bone, which contained tumor cells with the same histological features. Accordingly, the present tumor might be interpreted as a malignant plexiform tumor of the uterus, an unusual variant of epithelioid leiomyosarcoma.

Biomarkers, Tumor↗
PubMed1996

Sex differences in susceptibility to viral infection of the central nervous system.

We have characterized striking differences in recovery of male and female BALB/c and BALB/c-H-2dm2 (dm2) mice from an experimental neurotropic viral infection of the central nervous system (CNS). Following intranasal inoculation of vesicular stomatitis virus (VSV), assays of tissue homogenates from female mice produced lower viral titers. There was also a significant reduction in the spread of virus from the rostral to caudal end of the brain in female mice. Enhanced recovery by female mice of both strains in response to this viral insult correlates with increased levels of Nitric Oxide Synthase (NOS) types I, II, and III expression, an increased prevalence of reactive astrocytes, earlier and enhanced levels of expression of Major Histocompatibility Complex (MHC) class II molecules on astrocytes, endothelial and microglial cells, and increased T cell infiltration in the female BALB/c mouse. Taken together, these findings document sexual dimorphism in CNS immunity, and may provide an understanding of some of the mechanisms underlying many sex-biased diseases.

Animals↗
PubMed1996

Interferon-gamma induced type I nitric oxide synthase activity inhibits viral replication in neurons.

Type I NOS expression increases in OB neurons during VSV infection. Immunocytochemical staining of NB41A3 cells indicates constitutive expression of interferon (IFN)-gamma receptor and type I NOS. IFN-gamma treatment of NB41A3 cells increased NO production and type I NOS protein. In vitro replication of VSV, polio virus type I, and Herpes Simplex virus type I (HSV-1) is significantly inhibited by IFN-gamma induced type I NOS and antagonized by NOS inhibitors. In contrast, while IFN-gamma treatment inhibited influenza and Sindbis virus replication, a different pathway(s) was involved. The isoform-selective NOS inhibitor. 7-nitroindazole (7NI) was used to treat mice, resulting in a 10-fold higher titer of virus in brain homogenates, and abrogated the recovery-promoting effect of interleukin-12 treatment. Thus, IFN-gamma induced type I NOS activity may play an important role in host immunity against neurotropic viral infections.

Animals↗
PubMed1996

T cell receptor (TCR) repertoire and function of human epidermal T cells: restricted TCR V alpha-V beta genes are utilized by T cells residing in the lesional epidermis in fixed drug eruption.

Human epidermis contains a phenotypically heterogeneous population of T cells. No information however, is available regarding the TCR repertoire of these T cells and their relevant physiologic and pathologic functions in vivo. To this end, T cells were prepared from the lesional epidermis in two patients with fixed drug eruption (FDE) and their phenotype, function and TCR repertoire were examined in parallel. Both epidermal T cells, termed FDE-1 and -2 cells, respectively, expressed alpha beta TCR, but displayed some phenotypic heterogeneity. These T cells were induced to display cytolytic activity by ligation of the CD3/TCR-alpha beta complex. Comparative analyses of TCR V alpha and V beta expression in the epidermal T cells and the paired peripheral blood lymphocytes (PBL) by quantitative polymerase chain reaction (PCR) demonstrated that the epidermal T cells, but not the paired PBL, utilized a very limited range of V alpha and V beta genes. These results indicate that some expansion or preferential migration of epidermal T cells that recognize a restricted set of antigens expressed within the epidermis could occur in situ following ingestion of the causative drug. The persistence of these epidermal T cells in FDE lesions suggests their pathologic role in a drug-induced flare.

Base Sequence↗