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Biomedical subjects

H Okada

Publications and source records attributed to H Okada.

At least 469 records · Page 26Linked to original sources
PubMed1996

Expression and regulation of neuropeptide Y messenger ribonucleic acid in cultured immature rat Leydig and Sertoli cells.

Neuropeptide Y (NPY) potentiates the release of gonadotropins from the pituitary in response to GnRH in the hypothalamus and modulates reproductive function. In the present study, we showed that 1) specific organs in the male rat reproductive tract express NPY messenger RNA (mRNA); 2) the multifactorial regulation of NPY mRNA in rat Leydig and Sertoli cells is temporally and hormonally regulated in vitro; 3) both Sertoli cell factor(s) and germ cell factor(s) potentiated to stimulate NPY gene levels in Leydig cells; and 4) intense NPY immunoreactivity was detected in cultured Leydig cells. Using the RT-PCR method, we found that Leydig cells, Sertoli cells, epididymis, and vas deferens expressed NPY mRNA, whereas germ cells, seminal vesicle, and prostate did not. Northern blot analyses showed that NPY mRNA was not expressed in freshly isolated immature Leydig cells, but that NPY mRNA levels were increased by the addition of LH, cytokines such as interleukin-1 alpha and -1 beta, forskolin, or phorbol 13-myristate 12-acetate. Npy mRNA levels in immature Sertoli cells were also increased by FSH. In addition, a germ cell factor(s) secreted from pachytene spermatocytes or round spermatids purified by centrifugal elutriation as well as a Sertoli cell factor(s) stimulated by FSH increased NPY gene levels in Leydig cells. Immunocytochemical analyses showed that the immunostaining was more marked in Leydig cells than in Sertoli cells in vitro. These findings indicate that testicular NPY gene expression is induced in Leydig cells or Sertoli cells by gonadotropins or cytokines within the testes, and that factors secreted from Sertoli cells or germ cells affect NPY gene expression in Leydig cells in vitro. Our findings suggest that NPY expressed in the reproductive system may modulate reproductive function as well as that in the nervous system.

Animals↗
PubMed1996

Simple detection of xylosidase activity in single colonies, using 1-naphthyl-beta-D-xylopyranoside.

Since the xylosidase of Bacillus pumilus hydrolyzed 1-naphthyl-beta-D-xylopyranoside (naphthyl-X) to produce xylose and 1-naphthol and a chromogenic azo compound is produced by coupling 1-naphthol and Fast Blue Salt B, a simple method for detection of xylosidase activity in single colonies was studied. Escherichia coli JM109 carrying the xylosidase gene of B. pumilus was cultivated at 37 degrees C for 18 h on a LB plate containing 0.5 mg/ml naphthyl-X, and then the plate was overlaid with 3 ml of a top layer containing 24 mg of agar and 6 mg of Fast Blue Salt B. After incubation of the plate at 37 degrees C for 1 h, each colony became reddish-brown. Even a small colony with xylosidase on the plate was easily distinguished from colonies without the enzyme.

Bacillus↗
PubMed1996

Dipeptidyl aminopeptidase IV from Pseudomonas sp. WO24.

Dipeptidyl aminopeptidase IV from Pseudomonas sp. WO24 was purified as two molecular forms of 84 and 82-kDa by SDS-PAGE. Peptide mapping and N-terminal sequence analyses indicated that both proteins might be derived from the same protein, and that the 82-kDa molecule might be a truncated form from the 84-kDa molecule at least at the N-terminus. The DAP IV gene of Pseudomonas sp. WO24 was cloned and expressed in E. coli. The enzyme expressed in E. coli JM109 harboring a hybrid plasmid, pYO-6A, with about a 3-kbp fragment containing the DAP IV gene, was purified with an activity recovery of 24%. The recombinant enzyme also had the same two molecular forms, though the ratio of the two forms (about 1:1) was different from that of the native ones (about 1:4). The native and recombinant enzyme preparations had similar specific activities, suggesting that the 84 and 82-kDa molecules are in an active form and have almost the same specific activity. The molecular mass, the subunit number, the substrate specificity, and the effects of various inhibitors of the native enzyme indicated that this enzyme was a typical DAP IV and had properties similar to those of Flavobacterium meningosepticum rather than others.

Amino Acid Sequence↗
PubMed1996

A simple assay for xylanase using o-nitrophenyl-beta-D-xylobioside.

We measured xylanase activities upon eight chromogenic substrates, o- or p-nitrophenyl-beta-D-xylopyranoside (oNP-X or pNP-X) and o- or p-nitrophenyl-beta-D-xylooligosaccharides (oNP-Xn or pNP-Xn, n = 2-4), and studied for their uses as substrates in a kinetic study. The Kcat and K(m) of Bacillus pumilus xylanase (EC 3.2.1.8) activities for pNP-X2 were 0.24s-1 and 0.5 mM, respectively. The relative xylanase activities with the other substrates to that with pNP-X2, pNP-X3, pNP-X4, oNP-X, oNP-X2, oNP-X3, and oNP-X4 were < 0.001, 9.4, 9.7, < 0.001, 19, 190, and 200, respectively. HPLC analysis of the digestion products of oNP-X2 or pNP-X2 showed that the xylanase hydrolyzed each of the substrates only at the ether bond between nitrophenol and xylobiose. All ether bonds of pNP-X3, oNP-X3, pNP-X4, or oNP-X4 were hydrolyzed by the xylanase and further hydrolyses proceeded in the digestion products, e.g., oNP-X2 and oNP-X3 from oNP-X4. Therefore, oNP-X2 was screened as a useful substrate in a kinetic study of the xylanase. The K(m) and Kcat of the xylanase for oNP-X2 were 0.38 mM 2.29s-1, respectively. Thermodynamic studies showed that the higher reaction rate obtained with oNP-X2 than that with pNP-X2 was due to a significant decrease in the activation energy change, despite a decrease in the activation entropy change.

Bacillus↗
PubMed1996

Primary sclerosing cholangitis in Japanese patients: association with inflammatory bowel disease.

To characterize primary sclerosing cholangitis (PSC) in Japanese patients and its association with inflammatory bowel disease (IBD), 155 reported cases of PSC, including 6 cases of our own, were reviewed. The prevalence of IBD was less in Japanese PSC patients than in Western patients (23% versus 62-100%). Japanese PSC patients with IBD were younger (mean age, 33.1 versus 51.8 years) and were more often women (51% versus 36%) than those without IBD. Seventy-four percent of PSC patients with IBD had extensive colonic lesions, and 89% of those developed IBD simultaneously, with or prior to PSC. There were 3 cases of neutrophilic cholangitis among the PSC patients with IBD but none in those without IBD. Based on these observations, we speculate that there may be subtypes of PSC which differ pathophysiologically.

Adolescent↗
PubMed1996

Ultrastructure of the ankylotic area in the osteopetrotic op/op mouse.

The op/op mouse, which carries an osteopetrotic mutation, suffers from complete failure of tooth eruption. Commonly the teeth are ankylosed to the bone. Previous reports of ankylosis in the op/op mouse have been based on light microscopy. The aim of this study was to clarify the ultrastructural features of the ankylotic area using the oolong tea extract (OTE) staining technique. The ultrastructural features of ankylosis did not parallel the findings of light microscopy. OTE staining clearly stained the collagen fibers of bone and tooth, and the space dividing the tooth and bone was revealed by transmission electron microscopy. In comparison, light microscopy failed to reveal this space and the ankylosis was unclear. The true ankylotic area was smooth and the tooth was tightly ankylosed to the bone.

Animals↗
PubMed1996

Tamsulosin and chlormadinone for the treatment of benign prostatic hyperplasia. The Kobe University YM617 Study Group.

The recent introduction of selective alpha-adrenoceptor blockers adds a further therapeutic option for the treatment of benign prostatic hyperplasia (BPH). Tamsulosin, a selective alpha 1-blocker, has proved effective in relieving irritative and obstructive symptoms caused by BPH. To investigate whether the combination of tamsulosin with the anti-androgenic drug chlormadinone is of further therapeutic benefit, 80 patients randomly received tamsulosin 0.2 mg daily, chlormadinone 50 mg daily or a combination of tamsulosin 0.2 mg and chlormadinone 50 mg daily for 16 weeks. Greater improvement in subjective symptoms of BPH was obtained with either tamsulosin alone or in combination with chlormadinone than with chlormadinone alone. However, the greatest improvement in objective uroflowmetric data was obtained with chlormadinone in combination with tamsulosin. Thus, the combination of tamsulosin with chlormadinone appears to be more beneficial than either of these agents used as monotherapy. Further investigation is required to fully evaluate the therapeutic effects of this combination. After the trial period one-third of the chlormadinone and tamsulosin/chlormadinone-treated patients needed no further treatment due to the satisfactory relief of symptoms. At 12 months follow-up, however, one-fourth of the patients had undergone transurethral resection of the prostate (TUR-P) regardless of medication. This suggests a limitation of the medical treatment of BPH.

Adrenergic alpha-Antagonists↗
PubMed1996

Two cases of small cell carcinoma of the prostate.

We describe the clinical and pathological findings in two Japanese men with small cell carcinoma of the prostate; case 1 was 58 years old and case 2 was 24 years old. Case 1 was initially diagnosed as a poorly differentiated adenocarcinoma of the prostate, stage D2, with marked elevation of serum neuron-specific enolase (NSE), carcinoembryonic antigen (CEA), and CA 19-9 levels. The patient had undergone castration and systemic chemotherapy. After three courses of chemotherapy, tumour markers were normalized. However, 6 months later serum levels of tumour markers again rose, and biopsy of the prostate revealed a small cell carcinoma component in the adenocarcinoma of the prostate and benign prostate hypertrophy. The patient was again treated with systemic chemotherapy but died within 1 year after relapse. In case 2, the patient presented with initial symptoms of lumbago and dysuria, and an enlarged prostate was radiologically diagnosed. Shortly after admission he developed ileus, and an exploratory laparotomy revealed a large tumour arising from the prostate and invading the peritoneal cavity. This tumour was pathologically diagnosed as a small cell carcinoma. The patient died shortly thereafter without responding to chemotherapy. Immunohistological evaluation was done using a panel of antibodies against NSE, chromogranin A, CEA, CA 19-9, prostatic acid phosphatase (PAP), prostate-specific antigen (PSA), leukocyte common antigen (LCA), epithelial membrane antigen (EMA), adrenocorticotropic hormone (ACTH), calcitonin, serotonin, gastrin, vasoactive intestinal peptide (VIP), and glucagon. CEA was intensely positive in the tumour lesions from case 1, and NSE and ACTH were focally positive, and calcitonin, serotonin, CA 19-9, and PSA were weakly positive only in several cells in the tumour lesions from case 1. In the tumour lesion from case 2, NSE was intensely positive, and chromogranin A was weakly positive. These findings support the neuroendocrine nature of this neoplasm.

Adenocarcinoma↗
PubMed1996

Involvement of oxidative stress in D-xylose-induced cataractogenesis in cultured rat lenses.

In order to clarify the involvement of oxidative stress in in vitro sugar-induced cataractogenesis, we examined changes in lipid peroxide, reduced glutathione, vitamin E, and water contents following cataractogenesis in rat lenses cultured with 20 mM D-xylose over a period of 24 h. In D-xylose-treated lenses, an apparent opacity appeared at the equator after 6 h of D-xylose treatment, increases in lipid peroxide and water contents and decreases in reduced glutathione and vitamin E contents occurred with the appearance of opacity. We further examined the effect of the treatment of vitamin E in a liposomal form on cataractogenesis and the changes of lipid peroxide, reduced glutathione, vitamin E, water, and xylitol contents in rat lenses cultured with 20 mM D-xylose for 24 h. This vitamin E treatment significantly prevented not only cataractogenesis, but also an increase in lipid peroxide content and a decrease in vitamin E content in the D-xylose-treated lenses. However, the vitamin E treatment had no effect not only on a decrease in reduced glutathione content, but also on increases in water and xylitol contents, which are known to be induced via aldose reductase, in the D-xylose-treated lenses. These results indicate that not only osmotic stress but also oxidative stress should be involved in cataractogenesis in rat lenses cultured with D-xylose and support the involvement of oxidative stress in in vitro sugar-induced cataractogenesis.

Animals↗
PubMed1996

Does combined therapy of Ca-channel blocker and angiotensin converting enzyme inhibitor exceed monotherapy in renal protection against hypertensive injury in rats?

Either calcium channel blocker (CCB) or angiotensin converting enzyme inhibitor (ACEi) is used as an antihypertensive agent, and we are recommended to use them in combination to refractory hypertension with evidence dependent on clinical observations. We examined the renal protective effect of the combined therapy with calcium channel blocker (amlodipine) and angiotensin converting enzyme inhibitor (enalapril) against hypertensive renal injury in 5/6 nephrectomized spontaneously hypertensive rats (SHRs) with salt loading, comparing with monotherapy of each drug. Forty males SHRs with 5/6 nephrectomy and salt loading were divided to five groups: group 1 as control (n = 8), group 2 received 0.2 mg/kg/day of amlodipine (n = 8), group 3 received 0.2 mg/kg/day of enalapril (n = 8), group 4 (n = 8) and group 5 (n = 8) that were treated with 0.1 mg/kg/day and 0.2 mg/kg/day of each drug in combination respectively. Either amlodipine or enalapril had remarkable effects on reducing the increases in blood pressure and urinary protein excretion. In histopathological examination, it also suppressed renal injury significantly. Additional significant effect of combined therapy was not observed in blood pressure and urinary protein. There were not remarkable, additional effects of the combination of CCB and ACEi on protecting the remnant kidney in 5/6 nephrectomized SHRs fed a high-salt diet, possibly because sodium retention was not alleviated by the combination.

Amlodipine↗
PubMed1996

[Expression of decay-accelerating factor on CD8-positive lymphocytes as an index of aging and of host defense function].

Decay-accelerating factor (DAF) is a membrane glycoprotein that prevents complement activation on blood cells. Among CD8+ T cells, DAF-negative cells can be distinguished from DAF-positive cells. We computed the proportion of DAF-negative CD8+ T cells in the peripheral blood of 59 normal healthy subjects, 27 to 93 years old, and analyzed the differences between subjects of different ages. The proportion of CD8+ T cells that were DAF-negative correlated significantly and positively with age. We also studied these lymphocytes in patients with cerebrovascular dementia, Alzheimer's dementia, cancer, rheumatoid arthritis and systemic lupus erythematosus. The proportion of CD8+ T cells that were DAF-negative did not correlate significantly with age in patients with cerebrovascular dementia, Alzheimer's dementia or cancer, but it correlated significantly and positively with age in patients with rheumatoid arthritis and in those with systemic lupus erythematosus. Therefore, healthy subjects and patients with various diseases can be classified according to age and to the proportion of CD8+ T cells that are DAF-negative. This proportion can then be used as an index of aging and of host defense function.

Adult↗
PubMed1996

[DNA synthesis in the testes of infertile men with varicocele--image cytometeric analysis of proliferating cell nuclear antigen].

BACKGROUND: The analysis of cell kinetics of germ cells have been implicated as important clue to investigate the etiology of infertile patients. We examined the germ cell kinetics of varicocele testis using proliferating cell nuclear antigen (PCNA) immunostaing by image cytometry (CAS 2000), which is very accurate and useful method to evaluate the staining intensity. PATIENTS AND METHODS: Testicular biopsy specimen obtained from 28 cases of male infertility with left varicocele and 5 normal controls were quantitatively examined concerning PCNA expression. Positive rate of PCNA (PR) was expressed as the percent of nuclear area positively stained with PCNA monoclonal antibody compared with total nuclear area analyzed in more than 20 seminiferous tubules. A hematoxylin and eosin-stained sections, which were fixed in Bouin's solution were used to examine Johnsen's mean score by photomicroscopy. RESULTS: PR of right and left testes of varicocele patients were 11.3 +/- 4.8% and 11.3 +/- 4.1%, respectively. PR of normal testes was 21.7 +/- 3.1%. PR of each side were reduced similarly and the difference of PR between right and left testes of varicocele patients were not significant. Bilateral PR was 11.4 +/- 4.1%. Bilateral PR was significant lower than that of normal testes (p < 0.001). Concerning varicocele grade, sperm concentration of seminogram, Johnsen's mean score and the improvement of seminogram, no significant correlations between PR and those were observed. CONCLUSION: PR evaluated by image cytometry is very useful biological parameter to assess the germ cell kinetics. In varicocele patients, not only left side but also right side of testes were deteriorated in the cell kinetics and the decrease in DNA synthesis is one of the causes that have deleterious effects on spermatogenesis.

Adult↗
PubMed1996

[Phase II study of paclitaxel (BMS-181339) in patients with ovarian cancer by 3-hour intravenous infusion].

A phase II study of Paclitaxel in patients with ovarian cancer by 3-hour intravenous infusion was undertaken by a cooperative study group of 30 institutes. Of 66 cases enrolled, 57 cases were evaluable for efficacy, and 63 cases were evaluable for safety. In spite of the fact that all cases for efficacy evaluation were previously treated with chemotherapy including platinum-based drugs, 2 cases of complete response (CR) and 15 cases of partial response (PR) were observed, with a response rate of 29.8% (The 95% confidence interval of response rate was 18.4-43.4%). Paclitaxel also showed 28.2% (11/39) response rate in patients refractory to treatment by platinum-based drugs. Histologically, the response rates were 28.9% (11/38) in serous adenocarcinoma, 40.0% (2/5) in clear cell adenocarcinoma and 25.0% (1/4) in mucinous adenocarcinoma. As the major laboratory abnormalities, leukopenia, neutropenia and decrease in hemoglobin were observed with incidence rates of 98.4% (62/63), 95.2% (59/62) and 85.7% (54/63), respectively. However, these abnormalities were clinically manageable by either withdrawal of medication, administration of antibiotics, G-CSF or metachysis etc. In addition, thrombocytopenia, elevation in GOT and GPT were seen with moderate incidence. Peripheral neuropathy was a major adverse symptom with an incidence of 79.4% (50/63), followed by alopecia, myalgia, arthralgia and fever. However, the majority of these adverse reactions were less than grade 3. From these findings, we confirmed that 3-hour intravenous infusion of Paclitaxel was a clinically useful chemotherapeutic agent in patients with ovarian cancer.

Adult↗
PubMed1996

[Comparison between high-resolution computed tomography and 99mTc-technegas SPECT pulmonary emphysema].

Scintigraphy with 99mTc-technegas was recently introduced for clinical imaging of lung ventilation. This method has been found to be useful in emergencies, to be more suitable for single photon emission computed tomography (SPECT) than other agents used in ventilation scintigraphy, and could reveal abnormalities in ventilation more easily than high resolusion computed tomography (HRCT) in pulmonary emphysema. We compared 99mTc-technegas SPECT with HRCT in six regions: the right upper, middle, and lower lobes, the left upper lobe, the lingula, and the left lower lobe, in 15 patients with pulmonary emphysema. Patients with centrilobular emphysema tended to show stronger changes in upper lobes than in lower lobes on both 99mTc-technegas SPECT and HRCT. Some regions showed no change on HRCT but various changes on 99mTc-SPECT. Patients with panlobular emphysema showed severe changes on 99mTc-SPECT in lower lung fields in which well-demarcated areas of low attenuation were not seen on HRCT. We conclude that 99mTc-SPECT is useful for detecting early changes and panlobular changes in pulmonary emphysema.

Adult↗
PubMed1996

A phenomenological model describing pharyngeal pulsing in the nematode Caenorhabditis elegans anesthetized by alcohol.

The recovery process of the suppressed pharyngeal pulsation in the nematode has been investigated for several concentrations of a homologous primary alcohol series (CnH2n-1OH, n = 1,2,3). A mathematical model describing the time course of the recovery process is phenomenologically constructed by using two time constants of delay time tD and recovery time tau. The values of tD and tau are obtained by fitting the equation to experimental data. The obtained values increase with increasing alcohol concentration. To observe the characteristics of tD and tau against the alcohol of order n, the inverse of these time constants are computed at 25 v/v% concentration and plotted on a semi-logarithmic scale. The plot curves decrease non-linearly and are dissimilar to the well-known curves illustrating the importance of lipid solubility in the cell membrane in anesthetic phenomena.

Alcohols↗