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Biomedical subjects

Y Okuda

Publications and source records attributed to Y Okuda.

At least 145 records · Page 8Linked to original sources
PubMed1998

Stem cell factor in human seminal plasma as a marker for spermatogenesis.

OBJECTIVES: To measure the level of stem cell factor (SCF) in human seminal plasma to determine whether SCF may be useful in evaluating the ability to produce sperm and search the role of SCF in the testes. METHODS: We measured the level of SCF in seminal plasma obtained from 108 males, including idiopathic azoospermia due to germ cell aplasia (n = 10), oligospermia (n = 50), asthenospermia (n = 31), and normospermia (n = 1 7). The expression of SCF messenger ribonucleic acid in the human testis was evaluated by reverse transcriptase polymerase chain reaction (RT-PCR). The correlation between its level and clinical findings was also evaluated. RESULTS: RT-PCR showed a larger form that encoded the soluble protein and a smaller form that encoded the membrane-associated form of SCF in the human testis. The similar ratio of the larger form to the smaller one was observed both in the testis of normal and oligospermic men. The level of SCF is significantly correlated with the sperm count (r = 0.214; P < 0.05). CONCLUSIONS: The level of SCF in seminal plasma appeared to predict the ability to produce sperm. Thus, this factor may play an important role in spermatogenesis.

Humans↗
PubMed1998

Fas has a crucial role in the progression of experimental autoimmune encephalomyelitis.

To investigate the role of Fas in experimental autoimmune encephalomyelitis (EAE) in mice, we examined the susceptibility of EAE in C57BL/6 (B6).lpr mice lacking Fas. The frequency of myelin oligodendrocyte glycoprotein (MOG)-induced EAE in B6.lpr mice was significantly lower than that in B6 mice (19% vs 94%). However, no significant difference was observed between them in either the lymphocyte proliferation response or antibody reactivity to MOG. In addition, the histological examination and semiquantitative reverse transcriptase polymerase chain reaction analysis revealed that the infiltration of inflammatory cells and the up-regulation of gene expression for inflammatory cytokines occurred in the central nervous system (CNS) of B6.lpr mice immunized with MOG, even if they showed no clinical sign. These results indicate that Fas may contribute to the pathogenesis of EAE and may play a crucial role in the expansion of inflammation and/or myelin destruction in the CNS rather than in the activation of encephalitogenic T cells in the periphery and/or the breakdown of blood brain barrier.

Animals↗
PubMed1998

Aminoguanidine, a selective inhibitor of the inducible nitric oxide synthase, has different effects on experimental allergic encephalomyelitis in the induction and progression phase.

To elucidate the role of excessive nitric oxide (NO) via the inducible nitric oxide synthase (iNOS) in experimental allergic encephalomyelitis (EAE), the effect of a selective iNOS inhibitor, aminoguanidine, was investigated using mice with actively induced EAE. Administration of aminoguanidine by intraperitoneal or intracisternal injection from day 2 to day 12 after immunization produced a significant delay in the onset of EAE. On the other hand, administration of aminoguanidine by intraperitoneal or intracisternal injection for 10 days after the onset of EAE enhanced the clinical severity and mortality rate and hastened the onset of relapse significantly. The histological study at day 11 after the onset revealed that more inflammatory cells were present in the central nervous system of mice treated with aminoguanidine as compared with mice without aminoguanidine treatment. These results suggested that NO via iNOS was a pathogenetic factor in the induction phase of EAE, but had an inhibitory role in the progression phase of EAE. Although the effect of NO synthase inhibitors on EAE has been controversial, the present study suggested that the timing of administration might be an important consideration and might explain the previous contradictory reports.

Acute Disease↗
PubMed1998

Increase in serum vascular endothelial growth factor levels during altitude training.

The present study was performed to evaluate the effects of physical exercise at altitudes on serum vascular endothelial growth factor (VEGF) levels. Eight subjects underwent intensive swimming training for 21 days at 1886 m. After altitude training commenced, red blood cell (RBC) counts and erythropoietin levels increased, but both haemoglobin and haematocrit levels did not change significantly. The serum level of VEGF, measured by means of a highly sensitive chemiluminescence (ELISA), showed a transient decrease 10 days after start of the altitude training, thereafter increasing significantly to reach a peak level 19 days later, rising from 23.0 +/- 5.3 to 46.0 +/- 14.6 pg mL-1 (P < 0.05 vs. before). On return to low altitude in Japan, the level of VEGF decreased, and 1 month later had returned to initial levels. Endurance training at altitudes increases serum VEGF levels; this could be an adaptive reaction to hypoxic conditions. This result suggests that VEGF may provide a new physiological parameter for hypoxic stress imposed by high altitude training.

Adult↗
PubMed1998

The development of autoimmune encephalomyelitis provoked by myelin oligodendrocyte glycoprotein is associated with an upregulation of both proinflammatory and immunoregulatory cytokines in the central nervous system.

Experimental autoimmune encephalomyelitis (EAE) is an inflammatory disease of the central nervous system (CNS). We previously reported upregulation of gene expression for a number of proinflammatory cytokines, interleukin-1beta (IL-1beta), IL-2, IL-6, tumor necrosis factor-alpha (TNF-alpha), TNF-beta, and interferon-gamma (IFN-gamma), in the CNS of mice with myelin basic protein (MBP)-induced relapsing EAE by using semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR). However, in these mice there was no significant increase of gene expression for immunoregulatory cytokines (IL-4, IL-10, transforming growth factor-beta [TGF-beta]). We report here that gene expression for both proinflammatory and immunoregulatory cytokines increased during the course of disease in the CNS of mice with myelin oligodendrocyte glycoprotein (MOG)-induced nonrelapsing EAE. These results indicate that the gene expression pattern of immunoregulatory cytokines in the CNS may be different between MBP-induced and MOG-induced EAE and that it may influence the type of disease. Accordingly, the course of the disease may be influenced by the interplay between the proinflammatory and immunoregulatory cytokines.

Animals↗
PubMed1998

IL-6-deficient mice are resistant to the induction of experimental autoimmune encephalomyelitis provoked by myelin oligodendrocyte glycoprotein.

The role of IL-6 in experimental autoimmune encephalomyelitis (EAE) provoked by myelin oligodendrocyte glycoprotein (MOG) was investigated using IL-6-deficient mice. We show here that IL-6-deficient mice were resistant to the MOG-induced EAE as compared to wild-type mice (one out of 18 versus 17 out of 20). The delayed-type hypersensitivity response, lymphocyte proliferation response and antibody reactivity to MOG in IL-6-deficient mice were significantly lower than those in wild-type mice. Furthermore, the histological examination revealed that no infiltration of inflammatory cells was observed in the central nervous system of IL-6-deficient mice. These results indicate that IL-6 may play a crucial role in the induction phase of EAE. Given the potential relevance of this animal model for multiple sclerosis (MS), it is possible that anti-IL-6 therapy may be useful in the prevention of relapses of MS.

Animals↗
PubMed1998

Rapid serodiagnosis of Mycobacterium avium-intracellulare complex infection by ELISA with cord factor (trehalose 6, 6'-dimycolate), and serotyping using the glycopeptidolipid antigen.

Mycobacterium avium-intracellulare complex (MAC) is one of the most important opportunistic pathogens, particularly in patients with acquired immunodeficiency syndrome (AIDS). The aim of this study was to determine whether an enzyme-linked immunosorbent assay (ELISA) using trehalose 6,6'-dimycolate (TDM) as an antigen can be used for the rapid serodiagnosis of MAC infection. We also identified MAC serotypes by ELISA using serotype-specific glycopeptidolipid (GPL) antigen. To confirm our findings, the thin-layer chromatographic (TLC) behavior of serotype-specific GPL of the strains isolated from MAC-infected patients was also tested. Forty patients infected with MAC and 30 healthy controls were tested. Thirty-two of the 40 MAC-infected patients had higher titers of serum antibodies against MAC TDM than against MTB TDM, while all 30 healthy control sera were unreactive to MAC TDM and MTB TDM. Results of the GPL ELISA indicated that 20 of the 40 MAC-infected patients' sera were reactive against serotype 4 GPL, 3 against serotype 8 GPL, and 1 against serotype 16 GPL. A TLC analysis of the GPL of the 40 MAC isolates showed that 16 strains were of serotype 4, 5 of serotype 8, and 2 of serotype 16. Results of the GPL ELISA were in good accord with those of the TLC analysis for most patients. Our findings suggest that ELISA using TDM is useful for rapid serodiagnosis of MAC infection, and that complementary ELISA testing using serotype-specific GPL gives additional detailed information concerning MAC serotypes.

Adult↗
PubMed1998

Decreased serum apolipoprotein AII/AI ratio in systemic amyloidosis.

OBJECTIVE: To investigate if serum apolipoprotein A-I and A-II (apoAI and apAII) concentrations change in subjects with systemic amyloidosis secondary to underlying disorders. METHODS: Serum concentrations of apoAI and apoAII were measured in 21 multiple myeloma patients, including eight with amyloidosis; 95 rheumatoid arthritis patients, including 45 with amyloidosis; and 73 haemodialysis patients, including 32 with amyloidosis. RESULTS: ApoAII values tended to be reduced in subjects with amyloidosis in each group, but could not effectively distinguish amyloidosis. However, apoAII/AI ratios were significantly lower in subjects with amyloidosis in all groups. The ratio of 0.2 had diagnostic sensitivity and specificity for amyloidosis; 50% and 100%, respectively, in multiple myeloma; 80% and 78%, respectively, in rheumatoid arthritis; and 46% and 90%, respectively, in patients requiring long term haemodialysis. CONCLUSION: The apoAII/AI ratio can be a useful biochemical marker of suspect amyloidosis in patients with underlying diseases, especially those with rheumatoid arthritis.

Amyloidosis↗
PubMed1998

Three cases of malignant pheochromocytoma treated with cyclophosphamide, vincristine, and dacarbazine combination chemotherapy and alpha-methyl-p-tyrosine to control hypercatecholaminemia.

We describe 3 cases of malignant pheochromocytoma with multiple metastases which were treated with cyclophosphamide, vincristine and dacarbazine (CVD) combination chemotherapy and alpha-methyl-p-tyrosine. Case 1 was operated on first but hypercatecholaminemia could not be completely controlled. Cases 2 and 3 received chemotherapy, CVD combination chemotherapy and/ or alpha-methyltyrosine and good control of hypercatecholaminemia was attained. In all cases it was possible to control hypercatecholaminemia during most of the time they were administered a-methyltyrosine despite the presence of tumors. None of the patients suffered hypertension crises. In our patients treatment with CVD plus a-methyl-p-tyrosine proved to be safe and ameliorated the clinical course.

Adrenal Gland Neoplasms↗
PubMed1998

Clinical outcome of stenting in superior vena cava syndrome associated with malignant tumors. Comparison with conventional treatment.

PURPOSE: We analyzed the clinical outcome of treatment with the expandable metallic stent (EMS) for the superior vena cava (SVC) syndrome associated with malignant tumors, and the results were compared with those of radiotherapy. MATERIAL AND METHODS: Of 33 patients with the SVC syndrome, 23 were treated by Gianturco EMS placement and 10 were treated by radiotherapy and/or chemotherapy alone. Of the 23 EMS patients, 11 had treatment before EMS placement and 12 had no treatment before EMS placement. RESULTS: After stenting, the clinical symptoms disappeared in 78% (18/23) of the patients, i.e. in 50% of the patients with intraluminal tumors, and in 93% of those with extrinsic compression. The clinical symptoms improved in 80% of patients who received radiotherapy. The mean duration of survival was 145 days in patients who underwent stenting, and 146 days in those receiving radiotherapy. However, the survival period differed significantly between patients with intraluminal tumors (44.9 days) and those with extrinsic compression (198.6 days). Between patients with previous treatment and those with no previous treatment, there was no significant difference in response rate or in survival period which were 82% versus 75%, and 127 days versus 162 days, respectively. CONCLUSION: The clinical symptoms showed similar improvement in patients receiving EMS placement or radiotherapy. EMS placement was effective in relieving clinical symptoms in patients who had failed to respond to radiotherapy.

Adult↗
PubMed1998

The frequency of serum amyloid A2 alleles in the Japanese population.

The incidence of serum amyloid A2 alleles (SAA2 alpha and SAA 2 beta) in the Japanese population was analyzed by PCR-RFLP analysis. The SAA2 alpha allele was predominant (approximately 90%) in both healthy controls and adult patients with rheumatoid arthritis. There was no significant association of allele patterns with AA amyloidosis in the patient group. These results are discussed in comparison with those of previous reports from other areas.

Adult↗
PubMed1998

[Diagnosis of small hepatocellular carcinoma by US angiography with intraarterial CO2 microbubbles imaging].

US angiography, enhanced with intraarterial CO2 microbubbles imaging, documented 40 nodules of hepatocellular carcinoma (HCC) lesser than 20 mm in diameter in 34 patients, which were convinced histopathologically. As to the imaging acuity of arterial vascularity in nodules, US angiography was compared with DSA and US color angio. The detection of arterial vascularity was possible in 34 (85.0%) of 40 nodules by US angiography, 26 (65.0%) by DSA, and 28 (70.0 %) by US color angio. US angiography was available for detection of HCC, particularly with small HCC lesser than 20 mm in size.

Carbon Dioxide↗
PubMed1998

[Urgent cesarean section under combined spinal and epidural anesthesia in a patient with aortitis syndrome].

We report the anesthetic management of a patient with aortitis syndrome using combined spinal and epidural anesthesia. A 28-year-old gravida with aortitis syndrome accompanied by faints was scheduled for an urgent cesarean section. Combined spinal and epidural anesthesia was thought to be better for this case in order to monitor the cerebral circulation by her consciousness level and to reduce the hemodynamic change during surgery as compared to spinal or epidural anesthesia alone. After inserting an epidural catheter at the Th 12/L 1 interspace, spinal anesthesia was performed with 1.5 ml of 0.3% dibucaine at the L 4/L 5 interspace. The level of analgesia was under L 1 with the pinprick method 10 min after the spinal anesthesia. Next, 5 ml of 1.5% mepivacaine was injected through the epidural catheter. The level of analgesia reached to Th 6 without major hemodynamic changes. A healthy 2740 g infant was delivered and she had an uneventful recovery. We conclude that combined spinal and epidural anesthesia is useful in a patient with aortitis syndrome undergoing an urgent cesarean section in order to monitor the cerebral circulation by the consciousness level and to reduce the hemodynamic change.

Adult↗
PubMed1998

[A patient with drug abuse who developed multiple psychotic symptoms during sedation with propofol].

We report a patient with drug abuse who developed multiple psychotic symptoms including euphoria, excitement, hallucination and delirium during sedation with propofol under spinal anesthesia. A 37-year-old man who had abused methamphetamines, thinner, phychomimetics and alcohol for 20 years was scheduled for skin transplant as day-case surgery. He was treated with cholorpromazine, haloperidol and flunitrazepam just before the surgery. Sedation with propofol under spinal anesthesia was thought to be suitable in order to prevent psychotic symptoms. After spinal anesthesia, propofol 5 mg.kg-1.h-1 was administered intravenously as sedation. However, euphoria and excitement appeared 10 min after the start of infusion. He also demonstrated excitement, hallucination and delirium under propofol 6-8 mg.kg-1.h-1. His symptoms were suppressed by intravenous injection of haloperidol 5 mg. We speculate that propofol may produce psychotic symptoms when it is used in patients with a history of drug abuse.

Adult↗
PubMed1998

[Visual defect due to chiasmic compression by the A1 portion of the anterior cerebral artery].

Unilateral nasal hemianopia is highly difficult to notice with bilateral vision intact, and only a few cases has been reported. There are several reported cases of quadrantic hemianopsia caused by cerebral lesions, but the defects were found bilaterally in all cases. There is only one reported case of which an aneurysm was believed to be the cause. We confronted 3 cases of unilateral nasal quadrantic hemianopia. In either case no ophthalmologic disorders could be found but magnetic resonance imaging revealed the compression of the optic chiasma by the A1 portion of the anterior cerebral artery. All three cases are presently under conservative therapy and receive routine evaluations. Nerve fibers from the upper and lower areas of the retina are routed complicatedly in the optic nerve in the periphery of the optic chiasma. From the presentation of the quadrantic hemianopia and from the radiological findings, we diagnosed that the visual defect was caused by vascular compression of the optic chiasma.

Adult↗