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Biomedical subjects

H Kobayashi

Publications and source records attributed to H Kobayashi.

At least 343 records · Page 19Linked to original sources
PubMed2000

Ryudocan expression by luteinized granulosa cells is associated with the process of follicle atresia.

OBJECTIVE: To evaluate the presence of ryudocan in follicular fluid (FF) and its possible correlation with FF E(2) and P, and to study the levels of ryudocan in granulosa-lutein cells stimulated with hCG. DESIGN: Controlled clinical study and in vitro experiment. SETTING: University teaching hospital. PATIENT(S): One hundred seven patients undergoing IVF. INTERVENTION(S): The FF and granulosa-lutein cells were aspirated from follicles 34 hours after an ovulatory gonadotropin bolus. MAIN OUTCOME MEASURE(S): FF ryudocan, E(2), and P levels as well as hCG-mediated induction of ryudocan. RESULT(S): Ryudocan was abundant in the FF; the concentration of ryudocan in human FF was estimated to be 305.5 +/- 200.8 ng/mL (mean +/- SD). Atretic follicles had higher concentrations of ryudocan (559.1 +/- 156.5 ng/mL). FF ryudocan levels were inversely correlated with FF E(2) (r = -0.5023) and P concentrations (r = -0.4459). A detectable amount of ryudocan was found in pooled granulosa-lutein cells. Ryudocan production was augmented by surge levels of hCG. CONCLUSION(S): Ryudocan is expressed in luteinized granulosa cells in vitro. The higher concentrations of ryudocan in FF of atretic follicles suggest an involvement of ryudocan in the process of atresia.

Adult↗
PubMed2000

Histology of the neobladder mucosa after sigmoidocolocystoplasty.

PURPOSE: The aim of this study was to examine the histopathology of neobladder mucosa biopsy specimens obtained routinely as part of postsigmoidocolocystoplasty (SCP) follow-up. METHODS: One hundred cases of SCP (mean age at surgery, 10.6 years) performed by the authors were examined for the presence of dysplasia or malignant changes in the mucosa of the neobladder using H&E and proliferating cell nuclear antigen (PCNA) staining. RESULTS: No dysplastic or malignant changes were identified in any case. Metaplasia was found in 5 cases and hyperplasia in 2. There were no major differences found on H&E and PCNA staining of specimens obtained after different periods of follow-up post-SCP; follow-up was short term (up to 5 years) in 44 cases, medium term (from 5 to 10 years) in 48 cases, and long term (over 10 years) in 8 cases. PCNA staining was significantly more intense in subjects who stopped regular bladder irrigations (BI) post-SCP and in subjects in whom bladder stones developed (P < .05; Welch's t test), compared with subjects who continued BI and subjects in whom bladder stones did not develop. CONCLUSIONS: After SCP, patients are advised to continue BI. Regular biopsies should be part of routine follow-up, especially in subjects with bladder stones.

Adolescent↗
PubMed2000

Effect of an antioxidant, ebselen, on development of chronic cerebral vasospasm after subarachnoid hemorrhage in primates.

BACKGROUND: Oxidation and/or free radical reactions after subarachnoid hemorrhage (SAH) may be involved in the development of chronic cerebral vasospasm. The inhibition of these reactions is thought to be one of the therapeutic strategies for prevention of cerebral vasospasm. We investigated the effect of Ebselen, a synthetic seleno-organic compound, which exhibits anti-oxidation by glutathione peroxidaselike activity to inhibit free radical reactions by lipid peroxidation on the development of chronic cerebral vasospasm in a primate model. METHODS: Seventeen monkeys were used. SAH was produced by introduction of a blood clot around the right middle cerebral artery and the right side of the circle of Willis in all animals. The monkeys were randomly divided into three groups according to Ebselen dosage: 1) no dosage or non-treated group; 2) high-dose Ebselen group; and 3) low-dose Ebselen group. The drug was administered at 10 mg/Kg in the high-dose group and 5 mg/Kg in the low-dose group twice a day in each group for 7 days after SAH. The vessel diameter was evaluated on angiograms before the induction of SAH and at Day 7 following SAH. RESULTS: In the untreated group, the angiograms showed significant (p < 0.05) reductions of the mean vessel caliber of the right internal carotid (ICA) (38 +/- 10% reduction) and the middle cerebral artery (MCA) (56 +/- 9.7%) compared with the baseline value before SAH. In the high-dose Ebselen-treated group, the mean percent reduction in vessel caliber of the right ICA (16 +/- 11%) and MCA (28 +/- 9.5%) on Day 7 angiograms were significantly (p < 0.05) lower than those in the nontreated group, whereas the mean percent reduction of these vessels in the low-dose Ebselen-treated group showed no significant difference compared with the untreated group. CONCLUSIONS: Chronic cerebral vasospasm was inhibited in the animals in which a relatively large amount of Ebselen was administered for 7 days after SAH. The results suggest that the oxidation or free radical reaction by lipid peroxidation after SAH might be involved in the pathogenesis of vasospasm, and that inhibition of these reactions by drugs, such as Ebselen, may have a promising effect for prevention of vasospasm.

Animals↗
PubMed2000

Clinical results of fetal obstructive uropathy treated by vesicoamniotic shunting.

OBJECTIVES: To report the clinical results of 5 fetuses after a vesicoamniotic shunting procedure (VASP). METHODS: Between 1995 and 1998, 5 patients (two with prune belly syndrome, one with a cloacal anomaly, one with urethral stenosis, and one with a sacrococcygeal teratoma) underwent VASP using a double-basket catheter. We used the following selection criteria: a fetus without chromosomal defects, with oligohydramnios, and with a predicted good renal function from sequential or single fetal urinalysis (sodium concentration, chloride concentration, and osmolarity at less than 100 mEq/L, less than 90 mEq/L, and less than 210 mOsm, respectively). RESULTS: The mean gestational age was 20.8 +/- 6.9 weeks at diagnosis, 24.2 +/- 6.0 weeks at VASP, and 30.6 +/- 6.2 weeks at delivery. In our study, 2 of 5 patients survived. One of the patients with prune belly syndrome was 18 months old at last follow-up, with hydrocephalus and a creatinine level of 0.2 mg/dL. The patient with the cloacal anomaly was 4 years old at last follow-up and had signs of clonic convulsion. However, psychomotor development was delayed in both. Of the 3 patients who died, 2 died after birth, and the autopsy determined death was due to pulmonary insufficiency. The patient with urethral stenosis died in utero. CONCLUSIONS: Although the principal purpose of VASP is to prevent pulmonary hypoplasia and dysfunctional kidneys, VASP was not always effective, as the outcomes were poor in most of our patients. A greater standardization of patient selection and a large cohort study in the future should be considered to assess VASP.

Amnion↗
PubMed2000

Prostaglandin E(2) enhances axonal transport and neuritogenesis in cultured mouse dorsal root ganglion neurons.

The effects of prostaglandin E(2) on axonal transport in cultured mouse dorsal root ganglion neurons were investigated by analysing the number of axonally transported particles under video-enhanced microscopy. Application of prostaglandin E(2) increased the number of particles transported in anterograde and retrograde directions. The EP(2) prostaglandin receptor agonist butaprost mimicked the effect of prostaglandin E(2), but the EP(1)/EP(3) prostaglandin receptor agonist 17-phenyl trinor prostaglandin E(2) and the EP(3) prostaglandin receptor agonist M&B 28767 had no effect. The membrane-permeable cyclic AMP analogue dibutyryl cyclic AMP and the adenylate cyclase activator forskolin mimicked the effect of prostaglandin E(2). The protein kinase A inhibitor H-89 reversibly reduced the number of particles in both anterograde and retrograde directions. The effects of prostaglandin E(2) and dibutyryl cyclic AMP were blocked by H-89. Taken together with previous biochemical studies showing that prostaglandin E(2) increases cyclic AMP levels, the present results suggest that prostaglandin E(2) enhances axonal transport via the EP(2) receptor and cyclic AMP-dependent protein kinase A pathway. We further investigated the role of prostaglandin E(2) in neurite growth. Prostaglandin E(2) increased both the number of cells exhibiting neurites and the neurite growth rate, operating by a similar mechanism to stimulation of axonal transport. Prostaglandin E(2) may modulate axonal transport to supply materials for morphogenesis as well as other functions in sensory neurons.

Animals↗
PubMed2000

Inhibition of beta-carotene-15,15'-dioxygenase activity by dietary flavonoids.

Beta-carotene-15,15'-dioxygenase is an enzyme responsible for providing vertebrates with vitamin A by catalyzing oxidative cleavage of beta-carotene at its central double bond to two molecules of retinal in intestinal cells. However, little data have been reported regarding regulation of the enzyme activity. We have evaluated the effects of antioxidants and dietary flavonoids on the beta-carotene dioxygenase activity in vitro using a pig intestinal homogenate as the enzyme source. 2,6-Di-tert-butyl-4-methylphenol (BHT), a synthetic antioxidant, strongly inhibited the activity at the level of 10(-6) M (a mixed-type inhibition), whereas butylated hydroxyanisole, nor-dihydroguaiaretic acid, n-propyl gallate, and curcumin were moderately inhibitory. Flavonoids such as luteolin, quercetin, rhamnetin, and phloretin remarkably inhibited the dioxygenase activity noncompetitively, whereas flavanones, isoflavones, catechins, and anthocyanidins were less inhibitory. The structure-activity relationship indicated that catechol structure of ring B and a planar flavone structure were essential for inhibition. The enzyme inhibition was also indicated in the cultured Caco-2 cells by the significantly reduced conversion of beta-carotene to retinol when incubated with BHT and rhamnetin at 2 microM and 5 microM, respectively. The results suggest that some dietary antioxidants derived from food sources modulate conversion of beta-carotene to vitamin A in intestinal cells.

Journal Article↗
PubMed2000

p53-regulated GML gene expression in non-small cell lung cancer. a promising relationship to cisplatin chemosensitivity.

The GML gene (glycosylphosphatidylinositol-anchored molecule-like protein gene) is a novel gene specifically induced by wild-type p53, which may participate in cell cycle control or the cell apoptotic pathway. Recent experiments suggest that the expression of this novel gene in cancer cells is closely associated with sensitivity to certain anticancer drugs. To elucidate the role of the gene expression in cisplatin (CDDP) chemosensitivity of non-small cell lung cancer (NSCLC), 30 surgically resected materials were examined by reverse transcriptase-polymerase chain reaction (RT-PCR). GML gene expression was detected in 9 (30%) samples. Its incidence was significantly higher in immunohistochemically p53-negative (P=0.040) or wild-type p53 tissues (P=0.041). On in vitro chemosensitivity testing using 29 primary tissues, six samples with GML gene expression showed good sensitivity to CDDP. In particular, in tissues with immunohistochemically p53-negative accumulation, those with GML gene expression showed significantly better in vitro sensitivity to CDDP (P=0.012). Clinically a good response to CDDP-based chemo(thermo)therapy for NSCLC patients with tumour residue or recurrence, was observed only in those with p53-negative accumulation and GML gene expression, in agreement with in vitro results. Thus, although the number of tested samples was small, GML gene expression is commonly detected in immunohistochemically p53-negative NSCLCs in close association with good sensitivity to CDDP. GML gene expression analysis may serve as a predictor of CDDP-based chemotherapy for patients with NSCLC.

Antineoplastic Agents↗
PubMed2000

Development of a host-vector system for Lactobacillus plantarum L137 isolated from a traditional fermented food produced in the Philippines.

Lactobacillus plantarum NC13, a strain derived from the L. plantarum strain L137 isolated from a traditional fermented food produced in the Philippines, contains 9 of the 15 plasmids in the parental strain. To construct a shuttle vector between L. plantarum and Escherichia coli for genetic manipulation of L137 and its derivatives, recombinant plasmids were prepared by using the 9-plasmid DNA mixture and an E. coli vector, pBluescript II SK+. The resultant recombinant plasmids were re-transferred to L. plantarum NCL21, an NC13-derived strain cured of 3 of the 9 plasmids, and 3 recombinant plasmids were obtained. The smallest plasmid, pRN14, contained a small cryptic plasmid, pLTK2, which is one of the plasmids in L. plantarum L137. Thus, the complete nucleotide sequence of pLTK2 was determined. The pLTK2 is 2295 bp in length, and has a major open reading frame of 951 bp. An encoded sequence of 317-amino acids showed extensive similarity with genes encoding replication protein (repA). A putative replication origin in pLTK2 also showed high homology to those of other gram-positive bacterial plasmids that replicate by the rolling circle mechanism. The shuttle vector pRN14 contained the erythromycin resistance gene and the ColE1 and pLTK2 replication origins. Transformation of L. plantarum strains with pRN14 by electroporation was optimized to give a transformation efficiency of 2 x 10(4) transformants/ mug plasmid. Plasmid pRN14 was stably maintained in strain NCL21, as well as in L. casei K95-5.

Journal Article↗
PubMed2000

Bone marrow transplantation for the treatment of X-linked adrenoleukodystrophy.

The effects of bone marrow transplantation (BMT) in X-linked childhood adrenoleukodystrophy (ALD) are described in four Japanese patients. Two older patients, 10-year-old boys with IQ 60 and difficulty in school, had favourable results. IQ levels and MRI findings were generally maintained after BMT. One patient showed improvement of gait disturbance. They have both attended ordinary schools after BMT, although a learning disorder persists. On the other hand, two other younger patients with a rapid course and indeterminate IQ at BMT showed deterioration of neurological functions. Indication for BMT seems to be a maintained IQ level, preferably higher than 80, since it seems to be difficult to normalize IQ level after BMT. Younger patients have higher risk of developing a rapidly progressive form of the disease. Identification of presymptomatic boys, and serial and careful follow-up by neuropsychological and neuroradiological studies, are essential prerequisites to successful BMT in X-ALD.

Adrenoleukodystrophy↗
PubMed2000

The expression and activation of matrix metalloproteinase-2 in rat brain after implantation of C6 rat glioma cells.

It has been reported that matrix metalloproteinases (MMPs) are highly expressed in malignant glioma cells and that this increased expression may facilitate the invasiveness of tumor cells. The authors investigated the expression and enzymatic activity of MMPs in rat brain during the growth of malignant gliomas at different time intervals. C6 rat glioma cells were unilaterally implanted into rat cerebral hemispheres. After 7 or 14 days, these brain tissues were prepared for SDS-PAGE zymography, Western blotting, immunohistochemistry, and in situ zymography. SDS-PAGE zymography and Western blotting revealed that the expression of proMMP-2 in rat brains with C6 glioma cells was significantly higher than that in normal or the sham-operated rat brains, and that the activated form of MMP-2 was detected only in the former but not in the latter. On immunohistochemistry, C6 glioma cells presenting invasive growth into the rat brain parenchyma and vessels demonstrated MMP-2 immunoreactivity. On in situ zymography, foci of invasive C6 glioma cells in rat brain tissue showed gelatinolytic activity. These results suggest that expression and activation of MMP-2 may be one of the crucial steps for glioma cell invasion into the brain parenchyma in vivo.

Animals↗
PubMed2000

K+ uptake by fermenting Escherichia coli cells: pH dependent mode of the TrkA system operating.

Escherichia coli accumulates K+ by means of multiple transport systems, of which TrkA is the most prominent at neutral and alkaline pH while Kup is major at acidic pH. In the present study, K+ uptake was observed with cells grown under fermentative conditions at an initial pH of 9.0 and 7.3 (the medium pH decreased to 8.4 and 6.8, respectively, during the mid-logarithmic growth phase), washed with distilled water and resuspended in a K+ containing medium at pH 7.5 in the presence of glucose. The kinetics for this K+ uptake and the amount of K+ accumulated by the wild type and mutants having a functional TrkA or Kup could confirm that K+ uptake by E. coli grown either at pH 9.0 or pH 7.3 occurs mainly through TrkA. The following results distinguish pH dependent mode of TrkA operating: (1) K+ uptake was inhibited by DCCD in cells grown either at pH 9.0 or pH 7.3, although the stoichiometry of K+ influx to DCCD-inhibited H+ efflux for bacteria grown at pH 9.0 varied with external K+ concentration, but remained constant for cells grown at pH 7.3; (2) K+ uptake was observed with an atpD mutant grown at pH 9.0 but not at pH 7.3; (3) The DCCD-inhibited H+ efflux was increased 8-fold less by 5 mM K+ added into a K+ free medium for bacteria grown at pH 9.0 than that for cells grown at pH 7.3; (4) the DCCD-inhibited ATPase activity of membrane vesicles from bacteria grown at pH 9.0 was reduced a little in the presence of 100 mM K+, but stimulated more than 2.4-fold at pH 7.3.

Carrier Proteins↗
PubMed2000

Atrophic dermatofibroma. Elastophagocytosis by the tumor cells.

A 55-year-old woman presented with an asymptomatic red plaque on the left upper back for 6 or 7 years. The lesion was depressed in response to finger pressure. The clinical diagnosis was anetoderma. Histopathologically, the characteristic cells of cellular dermatofibroma proliferated within the thinned dermis, which showed atrophy of about 60 or 70%. The proliferated cells were positive for factor XIIIa and negative for CD34. The involved dermis showed the loss of elastic fibers on elastica van Gieson stain. Electron microscopically, the proliferating cells phagocytized the elastic fibers. We report a typical case of atrophic dermatofibroma and show the possibility that the cause of this disease might be elastophagocytosis between the collagen fibers by the dermatofibroma cells.

Antigens, CD34↗
PubMed2000

A case of intravascular large B-cell lymphoma mimicking erythema nodosum: the importance of multiple skin biopsies.

BACKGROUND: Intravascular lymphoma is a rare disease characterized by the proliferation of neoplastic monuclear cells within the lumens of small blood vessels. The neoplastic cells are usually of B-cell origin, and rarely of T-cell or histiocytic origin. Although this clinicopathological entity of lymphoma has not been listed in general pathological classifications such as REAL classification or the Working Formulation, it is recently in the WHO classification scheme, which is essentially an updated REAL scheme, and the EORTC classification scheme. METHODS: In this report, a 62-year-old woman with intravascular large B-cell lymphoma was observed by clinical, histopathological, immunohistochemical and molecular methods. RESULTS: A 62-year-old woman presented with large erythematous macules on the bilateral thighs and lower legs. The lesions were accompanied with hard, tender, intradermal or subcutaneous nodules mimicking erythema nodosum. Histopathological examination in the first biopsy revealed non-specific panniculitis compatible with erythema nodosum. The second biopsy revealed emboli of atypical lymphocytes within many of the dilated and proliferated vessels in the deep dermis and subcutaneous tissue. These cells were positive for L-26 and kappa light chain, and negative for lambda light chain, factor VIII-related antigen, CD30, CD34, CD68 and UCHL-1. These findings confirmed the diagnosis of intravascular large B-cell lymphoma. A laboratory examination showed a high level of LDH and abnormal cells in the bone marrow. An MRI of the brain and computed tomographic (CT) scans of the chest and abdomen revealed no evidence of malignancy. Before the treatment, the size of the nodules decreased spontaneously by about 50% in one month and significantly in two months. Although combination chemotherapy, which consisted of CHOP, brought her partial remission, she experienced neurological symptoms 6 months after the initial treatment and died of brain metastasis 9 months after the treatment. CONCLUSIONS: This is a unique case for two following reasons: 1) the first biopsy revealed non-specific findings compatible with erythema nodosum; and 2) before the treatment, the nodules regressed spontaneously. Dermatologists should take multiple skin biopsies for EN lesions with the non-specific histopathological findings not to refute the existence of this disease.

Biopsy↗
PubMed2000

Individual diversities in interferon gamma production by human peripheral blood mononuclear cells stimulated with periodontopathic bacteria.

Polarization of type 1 (Th1) or type 2 (Th2) immune responses determines the prognosis of many infectious diseases. Interferon gamma (IFN-gamma) and IL-4 are key cytokines for the development of type 1 and type 2 immune responses, respectively. The aim of this study was to examine individual diversities in the polarization of type 1 and type 2 responses against periodontopathic bacteria. Peripheral blood mononuclear cells (PBMCs) from adult periodontitis (AP) patients and healthy (H) subjects were stimulated with Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans and Bacteroides forsythus with or without polymyxin-B, CTLA-4 Ig and anti-IL-12 antibody. IFN-gamma, IL-4 and IL-12 in the culture supernatant were measured. IFN-gamma and IL-4 producing cells were also examined using a multiparameter flow cytometric assay. Bone resorption rate in AP patients was calculated using Schei's method, and the probing pocket depth was also measured. PBMCs from AP patients and H subjects produced IFN-gamma and IL-12, whereas the production of IL-4 was rarely observed. Among the bacteria tested, A. actinomycetemcomitans was the most potent inducer of IFN-gamma and IL-12, and the reaction was inhibited by polymyxin-B. IFN-gamma was found to be produced by T cells in the PBMCs, and the production was significantly reduced by CTLA-4 Ig and anti-IL-12 neutralizing antibody. The amount of IFN-gamma produced by the PBMCs of AP patients and H subjects varied among individuals, and was significantly correlated with the amount of IL-12 produced in a particular individual. The production of IFN-gamma was not related with periodontal condition which was evaluated using bone resorption and pocket depth. These results suggest that polarization of type 1 response against periodontopathic bacteria is dependent on the production of IL-12 by monocytes, and that IL-12 stimulates IFN-gamma production. However, individual diversities of IFN-gamma production might not be directly related to the severity of periodontitis.

Adult↗
PubMed2000

Adrenomedullin inhibits spontaneous and bradykinin-induced but not oxytocin- or prostaglandin F(2alpha)-induced periodic contraction of rat uterus.

In isolated rat uterine strips, adrenomedullin (AM) inhibited the spontaneous periodic contraction in a concentration-dependent manner (IC(50)=22.3+/-0.7 nM). The inhibitory effect of AM was prevented by either AM(22-52), a putative antagonist for AM receptors, or calcitonin gene-related peptide (CGRP)(8-37), a putative antagonist for CGRP receptors. AM also attenuated bradykinin (BK)-induced periodic uterine contraction, which was blocked by AM(22-52) or CGRP(8-37), whereas AM had no effect on the periodic contraction caused by oxytocin or prostaglandin F(2alpha) (PGF(2alpha)). RT-PCR analysis showed that mRNAs for calcitonin receptor-like receptor (CRLR), receptor-activity-modifying protein (RAMP)1, RAMP2 and RAMP3 were expressed in the rat uterus. These results demonstrate that AM selectively inhibits spontaneous and BK-induced periodic contraction via activating receptors for AM and CGRP.

Adrenomedullin↗
PubMed2000

Short- and long-term differential effects of neuroprotective drug NS-7 on voltage-dependent sodium channels in adrenal chromaffin cells.

In cultured bovine adrenal chromaffin cells, NS-7 [4-(4-fluorophenyl)-2-methyl-6-(5-piperidinopentyloxy) pyrimidine hydrochloride], a newly-synthesized neuroprotective drug, inhibited veratridine-induced (22)Na(+) influx via voltage-dependent Na(+) channels (IC(50)=11.4 microM). The inhibition by NS-7 occurred in the presence of ouabain, an inhibitor of Na(+),K(+) ATPase, but disappeared at higher concentration of veratridine, and upon the washout of NS-7. NS-7 attenuated veratridine-induced (45)Ca(2+) influx via voltage-dependent Ca(2+) channels (IC(50)=20.0 microM) and catecholamine secretion (IC(50)=25.8 microM). Chronic (>/=12 h) treatment of cells with NS-7 increased cell surface [(3)H]-STX binding by 86% (EC(50)=10.5 microM; t(1/2)=27 h), but did not alter the K(D) value; it was prevented by cycloheximide, an inhibitor of protein synthesis, or brefeldin A, an inhibitor of vesicular transport from the trans-Golgi network, but was not associated with increased levels of Na(+) channel alpha- and beta(1)-subunit mRNAs. In cells subjected to chronic NS-7 treatment, (22)Na(+) influx caused by veratridine (site 2 toxin), alpha-scorpion venom (site 3 toxin) or beta-scorpion venom (site 4 toxin) was suppressed even after the extensive washout of NS-7, and veratridine-induced (22)Na(+) influx remained depressed even at higher concentration of veratridine; however, either alpha- or beta-scorpion venom, or Ptychodiscus brevis toxin-3 (site 5 toxin) enhanced veratridine-induced (22)Na(+) influx as in nontreated cells. These results suggest that in the acute treatment, NS-7 binds to the site 2 and reversibly inhibits Na(+) channels, thereby reducing Ca(2+) channel gating and catecholamine secretion. Chronic treatment with NS-7 up-regulates cell surface Na(+) channels via translational and externalization events, but persistently inhibits Na(+) channel gating without impairing the cooperative interaction between the functional domains of Na(+) channels.

Animals↗