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M Koga

Publications and source records attributed to M Koga.

At least 199 records · Page 11Linked to original sources
PubMed1998

Expression of selenoprotein-P messenger ribonucleic acid in the rat testis.

It has been suggested that a plasma protein, selenoprotein P, functions as an antioxidant and that its mRNA is expressed ubiquitously, including in the testis. To determine its physiological function, we have investigated the expression of selenoprotein-P mRNA in the rat testis. Northern blot analysis showed that selenoprotein P was exclusively expressed in the Leydig cell fraction. In situ hybridization experiments further supported this observation. Testes of rats administered ethylene dimethane sulfonate (EDS) were also examined by Northern blot analysis. Selective degeneration of Leydig cells by EDS treatment resulted in disappearance of selenoprotein-P mRNA from the testis. Furthermore, upon recovery, in association with regenerative differentiation of Leydig cells, reappearance of the selenoprotein-P mRNA was observed. These results indicated that selenoprotein-P mRNA was predominantly expressed in the interstitial Leydig cells.

Animals↗
PubMed1998

Association of mutations in the core promoter and precore region of hepatitis virus with fulminant and severe acute hepatitis in Japan.

It was recently reported that mutations in the precore and core promoter region of hepatitis B virus (HBV) are associated with fulminant hepatitis. The aim of this study was to investigate the association of mutations in the precore and core promoter region of HBV with fulminant and severe acute hepatitis. We studied Japanese patients with acute HBV infection, including seven patients with fulminant hepatitis, 12 with severe acute hepatitis and 41 with acute self-limited hepatitis. The presence of HBV mutants was examined by using a point mutation assay to detect a G to A transition at position 1896 in the precore region and an A to T transition at position 1762 and a G to A transition at position 1764 in the core promoter region. Significant differences in the proportion of mutations in the precore or core promoter region were present between patients with fulminant hepatitis and self-limited acute hepatitis (7/7 (100%) vs 4/41 (9.8%), P<0.01) and between severe acute hepatitis and self-limited acute hepatitis (6/12 (50.0%) vs 4/41 (9.8%), P<0.01). The frequency of mutation increased proportionately with the severity of disease in patients with acute HBV infection. Fulminant hepatitis B in Japan is closely associated with mutations in the core promoter and precore gene of HBV. Point mutation assays for HBV precore and core promoter analysis may be useful to predict the outcome of liver disease in patients with acute HBV infection.

Acute Disease↗
PubMed1998

Activation of peripheral blood monocytes and macrophages in Kawasaki disease: ultrastructural and immunocytochemical investigation.

Monocytes/macrophages are considered to play an important role in the pathogenesis of Kawasaki disease (KD). However, the morphological and immunocytochemical features of the cells in acute KD have not been investigated. The ultrastructural and immunocytochemical characteristics of peripheral blood CD14+ monocytes/macrophages sorted by a magnetic cell sorter (MACS) during the course of KD were, therefore, studied to evaluate their role in the disease pathogenesis. Electron microscopy showed that CD14+ monocytes/macrophages from patients with acute KD had nuclei with complex shapes, apparent nucleoli and abundant intracytoplasmic granules, some of which were positive for acid phosphatase. The quantity of intracytoplasmic granules was correlated with disease severity, in terms of the duration of fever, maximum level of C-reactive protein and the presence of coronary artery lesions (CAL), suggesting that the monocytes/macrophages were activated and showed increased phagocytosis. Immunocytochemical staining of smears made from cell suspensions of sorted CD14+ monocytes/macrophages was carried out using a monoclonal antibody against tumor necrosis factor (TNF)-alpha. The cytoplasm of monocytes/macrophages from patients with acute KD was strongly positive in comparison to that of cells from control subjects, suggesting that intracytoplasmic granules secrete TNF-alpha.

Acid Phosphatase↗
PubMed1998

Cerebral hypoperfusion during acute Kawasaki disease.

BACKGROUND AND PURPOSE: Kawasaki disease is a febrile disease of children notable for systemic vasculitis. There have been many previous reports of various complications, including disorders of the central nervous system. We evaluated cerebral perfusion during the acute stage in patients with Kawasaki disease. METHODS: Single-photon emission-computed tomography (SPECT) with 99mTc-hexamethylpropyleneamine oxime was performed in 21 children with acute stage Kawasaki disease. Follow-up SPECT and MRI were performed about 1 month after the first SPECT in patients who exhibited abnormal SPECT findings during the acute stage. RESULTS: In 6 of 21 children SPECT imaging demonstrated localized cerebral hypoperfusion without abnormal neurological findings or clinical symptoms, and the follow-up SPECT and MRI approximately 1 month after the first SPECT revealed no abnormalities. CONCLUSIONS: Some patients with Kawasaki disease have transient localized cerebral hypoperfusion at the acute stage.

Acute Disease↗
PubMed1998

Nicotinamide decreases cytokine-induced activation of orbital fibroblasts from patients with thyroid-associated ophthalmopathy.

We used flow cytometry to investigate the effects of nicotinamide, an inhibitor of poly (ADP ribose) synthetase, on the cell-surface expression of cytokine-induced human leukocyte antigen (HLA)-A,B,C antigen, HLA-DR antigen, intercellular adhesion molecule 1, CD44, and Fas expression in cultured orbital fibroblasts from patients with thyroid-associated ophthalmopathy. After two to seven passages, cultured orbital fibroblasts were incubated for 3 days with interferon gamma or tumor necrosis factor alpha in the presence of nicotinamide. Nicotinamide inhibited the induction of both HLA-DR and intercellular adhesion molecule 1 expression by cytokines on fibroblasts but did not interfere with induction of HLA-A,B,C, or CD44 expression. Nicotinamide also inhibited the proliferation of orbital fibroblasts, as assessed by a [3H]-thymidine incorporation assay and cell counts. Nicotinamide also enhanced the expression of the apoptosis-mediating protein Fas on fibroblasts. Our data suggest that nicotinamide inhibits cytokine-induced activation of fibroblasts and thus may decrease the autoimmune injury to the orbit in thyroid-associated ophthalmopathy.

Adipose Tissue↗
PubMed1998

Two patterns of clinical recovery in Guillain-Barré syndrome with IgG anti-GM1 antibody.

OBJECTIVE: To investigate the prognostic value of anti-GM1 antibody. BACKGROUND: Whether anti-GM1 antibody is a marker of poor prognosis due to axonal degeneration in Guillain-Barré syndrome (GBS) is a matter of controversy. METHODS: The clinical recovery of 41 consecutive GBS patients was analyzed. RESULTS: The Hughes functional grading scores were similar at the peak, and 1, 3, and 6 months after onset for the groups of patients with (n=19) and without (n=22) immunoglobulin (Ig) G anti-GM1 antibodies. However, the anti-GM1-positive group included significantly higher proportions of patients with poor recovery (inability to walk independently at 6 months, 5 of 19 versus 0 of 22; p=0.01) and those with a markedly rapid recovery (improvement by two or more Hughes grades within a month, 9 of 19 versus 4 of 22; p=0.05). The positivity of IgG anti-GM1 antibody correlated well with the electrodiagnosis of the acute motor axonal neuropathy pattern but was not always associated with poor prognosis. Anti-GM1-positive patients showed two different patterns of clinical recovery-their conditions improved slower or faster than those of the anti-GM1-negative patients, most of whom had acute inflammatory demyelinating polyneuropathy. CONCLUSIONS: Anti-GM1 antibody is not always a marker of poor prognosis and, besides axonal degeneration, early reversible effects other than demyelination could be part of the pathophysiology of Guillain-Barré syndrome with IgG anti-GM1 antibody.

Adult↗
PubMed1998

Isolated levocardia associated with absence of inferior vena cava, lobulated spleen and sick sinus syndrome. A case report.

We evaluated a 68-year-old male patient with isolated levocardia without intracardiac anomaly. The patient's condition was complicated by the absence of the inferior vena cava, a lobulated spleen and sick sinus syndrome. Isolated levocardia without intracardiac anomaly is very rare and only 25 cases of this disease have been reported, to our knowledge. In general, it is accepted that cardiac rhythm disorder is frequently observed in cases of isolated levocardia and/or absence of inferior vena cava. However, there are few cases of isolated levocardia without intracardiac anomaly complicated by the absence of the inferior vena cava, a lobulated spleen and apparent sick sinus syndrome.

Aged↗
PubMed1998

Successful application of three-dimensional transcranial power Doppler imaging in two stroke patients.

We applied a new technique of three-dimensional (3-D) transcranial power Doppler imaging to demonstrate the middle cerebral artery (MCA) in the 2 stroke patients. In the first patient, the 3-D power Doppler study clearly showed the horizontal portion, bifurcation, proximal portion of the upper and lower trunks, and the major branches of the lower trunk of the MCA. In the second patient, the 3-D power Doppler clearly revealed the proximal bifurcation of the left MCA. The 3-D transcranial power Doppler seems to be useful in making clear 3-D images of the MCA.

Cerebral Angiography↗
PubMed1998

[Direct effects of Chinese herbal medicine "hochuekkito" on sperm movement].

BACKGROUND AND PURPOSE: Chinese herbal medicine, "Hochuekkito" is widely used for male infertility in Japan. There have been many reports concerning its clinical usefulness but very few reports of in vitro experiments studying the mechanism of its effects. In addition to stimulating germ cells, we analyzed its direct effects on sperm using computer assisted semen analyzer (CASA). MATERIALS AND METHODS: Motile sperm were prepared using swim up technique from semen collected from ten healthy volunteers. Sperm movements (motility, velocity, linearity) were analyzed by CASA after adding either serum containing anti-sperm antibody (ASA) or normal serum with or without Hochuekkito. RESULTS: Two hours after adding serum with ASA, the decrease of sperm motility was significantly reduced from 25.1% (92.8%-->67.7%) to 12.5% (92.9%-->80.6%) by adding Hochuekkito. No significant difference in velocity and linearity was observed between two groups. By adding normal serum, any of three parameters differed significantly with or without Hochuekkito. CONCLUSION: Protective effects of Hochuekkito on sperm was suggested. Although normal sperm with ASA was used in this report, since the sperm of infertile patients are said to be more fragile, this results imply that direct protective effect is one of the mechanism of Hochuekkito for male infertility.

Adult↗
PubMed1998

[Mediastinal neurilemmoma originating in the right phrenic nerve: a case report].

We report on a 31-year-old man with a mediastinal neurilemmoma originating in the right phrenic nerve. The patient was admitted because of abnormal chest X-ray shadows observed during a routine checkup. A preoperative diagnosis of bronchial cyst in the mediastinum was made. The tumor was resected by video-assisted thoracic surgery. It was 3 x 4 x 3 cm in size, weighted 15 g, and originated in the right phrenic nerve. The histopathologic diagnosis was mediastinal neurilemmoma. Only 14 cases have been reported in the Japanese literature.

Adult↗
PubMed1998

[A case of pharyngeal-cervical-branchial variant of Guillain-Barré syndrome with IgG anti-GT1a antibody].

A 36-year-old man with pharyngeal-cervical-brachial variant of Guillain-Barré syndrome (PCB) was described. Neurologic examination revealed total ophthalmoplegia, pharyngeal-cervical-brachial weakness and hyporeflexia in the upper limbs, sparing power and tendon reflexes in the lower limbs. Enzyme-linked immunosorbent assay showed that he had high titer of IgG antibody to GT1a (1:32,000), which did not cross-react with GQ1 b or GD1a. Thin-layer chromatography immunostaining confirmed that his serum IgG reacted with GT1a. These findings show that IgG anti-GT1a antibody without cross-reactivity with GQ1b plays a role in the development of PCB.

Adult↗
PubMed1998

The effects of retraction forces applied to the anterior segment of orthodontic arch wires: differences in wire deflection with wire size.

Orthodontic arch wire deflection was studied in relationship to retraction forces applied to arch wires during anterior retraction with sliding mechanics. Two different sizes of orthodontic stainless steel arch wires (SS wires) .016" x .022" and .019" x .025", were examined. Retraction forces were generated using an elastic polymer material to measure arch wire deflection and applied to the arch wires by a commonly-used anterior retraction device with power chains hooked from the first molar areas to the pre-welded posts at distal site of the lateral incisors. The force application caused both the .016" x .022" and the .019" x .025" arch wires to deflect. The amount of deflection increased almost in proportion to the retraction force applied. With the same retraction force applied, the amount of deflection of the .019" x .025" wire was approximately 47.1% of that of the .016" x .022" wire.

Dental Arch↗
PubMed1997

Mapping of eight testis-specific genes to mouse chromosomes.

We previously identified eight testis-specific genes using antibodies raised against testicular germ cells. They are expressed during spermatogenesis and are presumed to be involved in testicular germ cell differentiation and sperm formation. We have mapped the genomic loci for these testis-specific genes using restriction fragment length variants in interspecific backcross mice. The calmegin gene (Clgn) was mapped to Chr 8. The synaptonemal complex protein gene 1 (Sycp1) probe hybridized with two sequences on different chromosomes; Sycp1-rs2 was mapped to Chr 3, whereas Sycp1-rs3 was mapped to Chr 7. The relaxin-like factor gene (Rlnl) was mapped to Chr 8, and collapsin response mediator protein 1 (Crmp1) was mapped to Chr 5. Three novel genes encoding testis-specific proteins A2 (Tsga2), A8 (Tsga8), and A12 (Tsga12) were mapped to chromosomes 3, X, and 10, respectively.

Animals↗
PubMed1997

The management of patients with dissection of the descending thoracic aorta: a comparison between closing and nonclosing dissections.

This study was designed to clarify and compare the clinical characteristics and prognoses of patients with closing and nonclosing dissection of the descending thoracic aorta. Between January 1991 and December 1994, 19 patients with closing dissection (Group A) and 20 with nonclosing dissection (Group B) underwent surgical repair or medical treatment at our institution. There were 29 men and 10 women, aged between 37 and 74 years, with a mean age of 62 years. There was a significant difference in age between the two groups, being 67 +/- 7 and 58 +/- 12 years for Groups A and B, respectively (P = 0.009). The presence of a concurrent abdominal aortic aneurysm was confirmed in 32% and 10% of Groups A and B, respectively (P = 0.095). A total of 15 patients experienced a variety of complications related to the dissection, but there were no significant differences in the morbidity rate between the two groups. Visceral ischemic disorders such as renal failure, leg ischemia, and ileus were the most common complications. The overall survival rate 4 years after the development of dissection was 80%, with no significant difference between the two groups. These findings led to the establishment of our policy to place all patients with dissection of the descending thoracic aorta on careful antihypertensive therapy and frequent follow-up imaging studies to assess the aorta, regardless of the condition of the false lumen.

Adult↗