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Biomedical subjects

H Sakai

Publications and source records attributed to H Sakai.

At least 865 records · Page 48Linked to original sources
PubMed1991

An improved fixation method for transmission electron microscopy for the histological study of the lens.

An improved fixation technique for transmission electron microscopic observation that enables good fixation of all areas of the rat lens was devised. Immersion fixation with 0.1 M phosphate-buffered 1.25% glutaraldehyde at 4 degrees C for 12 hours followed by postosmication produced good results for all areas of the lens--anterior, equatorial, and posterior zones. The technique was particularly suitable for maintenance of the shape of the lens since practically no irregularity, vacuolar degeneration, or expansion of the intercellular spaces was noted. This technique, which requires only a relatively short time, was also useful for the detection of early ultrastructural changes associated with cataract in spontaneously diabetic WBN/Kob rats. We anticipate that our procedure will be widely applied.

Animals↗
PubMed1991

Structural analysis of repetitive DNA sequences in the goat growth hormone gene region.

Two clones that contain goat growth hormone (gGH) genes were isolated from goat genomic library using goat growth hormone cDNA as a probe. One clone CgGH contained gGH1 gene, and another clone, EgGH, contained gGH2 and gGH3 genes. The clone EgGH contained 491 bp inserted sequence, just upstream of the gGH3 gene, which was not present in the clone CgGH. From the sequencing data of the flanking regions of these gGH genes, short interspersed repetitive sequences (SINES) were found. Four SINES's existed in the CgGH clone and eight SINES's existed in the EgGH clone. The number of the repetitive DNA sequences in the goat genome was estimated about 10(2) copies from the analysis of the reassociation rate. As the number of gGH genes (gGH1, gGH2, and gGH3) per genome was different among individual goats, DNA fragments containing gGH1 gene, and that containing gGH2 and gGH3 genes, were estimated to be allelic on the goat chromosome.

Animals↗
PubMed1991

[Role of microtubule cytoskeletons in the transduction of growth signals].

Attention has recently been paid to the role of microtubules in the transduction of growth signals, which has recently been establishing as a molecular function of microtubule cytoskeletons. The analysis of pathways in the signal transductions which are initiated by the activation of tyrosine-specific phosphorylation of growth factor receptors now seems to come to deal with events deeper inside the cell. It was recently found that MAP kinase which preferentially phosphorylates microtubule-associated protein 2 is largely activated at the G0/G1 transition by any of various growth stimuli. The kinase is also activated at the G2/M transition in the downstream of MPF (cdc2 kinase). Furthermore, it was suggested that a GTP-binding protein (51-kD protein) in the centrosome plays a role in the microtubule signalling at the onset of mitosis. This minireview discusses possible signalling pathway from the activation of tyrosine-specific protein kinase of the growth factor receptor to the initiation of mitosis.

Animals↗
PubMed1991

[Visual impairment complicated with meningioma].

Among 106 patients of meningioma surgically experienced the past 10 years between 1981 and 1990, twelve of meningioma with progressive visual impairment were analyzed in relation to postoperative visual outcome. There were four males and eight females, and the age ranged from 33 to 61 years with the average 48 years. The distribution of tumor location was 6 cases in tuberculum sellae, 3 cases in the inner side of sphenoid ridge, and 3 cases in olfactory groove. The size of tumor in each case was 2 to 7 cm in diameter, and in 8 cases more than 3 cm. The duration of visual disturbance was between 3 months and 10 years with the average 3 years. For all cases, surgical removal of the tumor was performed totally by pterional and bifrontal approach. Consequently, 58.3% of 7 cases had improved vision postoperatively, 16.7% of 2 cases remained unchanged, and 25.0% of 3 cases were worse, including one case of malignant meningioma, Visual outcome was mainly affected by a duration of symptoms, a tumor size, a preoperative visual impairment, and in special, a situation of optic nerve where compression of tumor itself and adherence to the surrounding tissues took place. On operation, great care should be paid for a case of long-standing, severe visual disturbance as demonstrating hemianopsia with visual narrowing less than 50 degree by perimetry, and also for preservation of the feeding arteries of optic nerves.

Adult↗
PubMed1991

A patient with primary plasma cell leukemia accompanied by an extensive polypoid infiltration of the gastrointestinal tract.

A 37-year-old male presented with primary plasma cell leukemia (PCL) with kappa-type Bence Jones proteinuria (BJP) and polyposis of the stomach and colon. His plasma cell leukemia was not preceded by a pre-existing multiple myeloma, and presented the complication of polyposis in both stomach and colon. Biopsy of mucosal lesions revealed marked accumulation of atypical plasma cells with positive cytoplasmic kappa-chain. No amyloidosis was present. His disease responded remarkably well to intermittent melphalan and prednisolone. This case represents an uncommon combination of primary plasma cell leukemia and polypoid gastrointestinal lesions with plasma cell infiltration.

Adult↗
PubMed1991

A case of insulin-secreting tumor successfully treated with diazoxide.

A 72-year-old patient was referred to our hospital because of a hypoglycemic crisis possibly due to an insulin secreting-tumor. Although its localization was assumed to be at the head of the pancreas as assessed by transhepatic venography with sampling, no mass lesion was detected by selective angiography, ultrasound, computerized axial tomography, magnetic resonance imaging and 67Ga-citrate scan. The patient was treated with diazoxide, because of poor localization and his age, insulin secretion was improved after both 30 and 60 min in the 75 g oral glucose tolerance test. The total amount of urinary C-peptide excretion decreased from 70.8 to 29.2 mcg/day. Thereafter, no hypoglycemic symptoms were observed during his admission. No side effects except mild liver damage were observed.

Aged↗
PubMed1991

Effect of cisapride on gastric emptying in diabetic patients without gastrointestinal symptoms.

The long-team effects of cisapride on gastric emptying and hormonal interaction in diabetic patients without gastrointestinal symptoms was evaluated. Gastric emptying was determined by the N-acetyl-p-amino-phenol (APAP) method before and after cisapride treatment. Gastric emptying improved significantly, from 5.95 to 8.04 micrograms/ml, after 6 weeks of treatment. Plasma concentrations of immunoreactive insulin (IRI), after 30 and 45 minutes in the gastric emptying test, increased significantly after treatment. It appeared that improvement of gastric emptying after loading with cisapride might be related to improved insulin secretion in diabetic patients without subjective symptoms of gastroparesis.

Acetaminophen↗
PubMed1991

Malignant lymphoma of the testis presenting as primary testicular tumor.

A case of malignant lymphoma of the testis is presented. A 49-year-old male presented with swelling and dull pain of his left scrotal content. The initial clinical diagnosis was left testicular tumor. Left high orchiectomy was performed immediately after admission and histopathology showed malignant lymphoma, large cell type, B-cell type according to the Lymphoma Study Group (LSG) classification. Extensive investigations revealed clinical stage lE, with no evidence of metastasis. Chemotherapy was initiated with vincristine, prednisolone, adriamycin and methotrexate (VEPA-M). After therapy, the patient is doing well without any evidence of metastasis.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1991

[A case of visual allesthesia].

A case of visual allesthesia is reported. A thirty-year-old right-handed man with a right temporo-occipital arteriovenous malformation underwent the surgery for extirpation of the lesion. Postoperatively he had left homonymous hemianopsia. Approximately 6 months after the surgery, he experienced the initial spell of generalized convulsion, followed by the episodes of visual allesthesia. He experienced illusory left hemonymous transpositions of objects viewed in the right homonymous field. The transposition occurred from normal to the defective visual field. The illusory image was palinoptic, persisting for up to several minutes after the real object was no longer in view. It was equal in shape with the original, and caused monocular diplopia. MRI showed a large area of postoperative changes. The lesion was located from the posterior half of the middle and inferior gyri of the right temporal lobe to the occipital and a part of the parietal cortex. And it extended into the right fusiform and lingual gyri. The right lateral geniculate body and the posterior part of thalamus were also involved. We speculated that this phenomenon may result from irritation of the affected brain and its surrounding areas, since the episode took place following the seizure.

Adult↗
PubMed1991

No increase in antibodies to six food antigens in Japanese patients with IgA nephropathy.

It has been postulated that mucosa-related antigens are involved in the development of IgA nephropathy. The aim of this study was to elucidate whether food antigens have any relation to IgA nephropathy in Japan. Sera from 15 patients with IgA nephropathy and 15 healthy controls were examined using an enzyme linked immunosorbent assay (ELISA). IgG, IgA, and IgM antibody titers were measured against six food-derived antigens, i.e. rice, soy bean paste, soy sauce, egg yolk, egg white and gluten, all of which are frequently found in the ordinary Japanese diet. No significant differences between patients and controls were found. It was concluded that food antigens appear to have little, if any, relation to IgA nephropathy.

Egg Proteins↗
PubMed1991

Inflammatory pseudotumor of the liver associated with acute myelomonocytic leukemia.

A patient with inflammatory pseudotumor of the liver associated with acute myelomonocytic leukemia (M4) is reported. He had spiking fever, epigastralgia, and elevated levels of serum C-reactive protein (CRP) and alkaline phosphatase (ALP). Ultrasonography showed a hypoechoic mass in the liver, and ultrasonically guided fine needle aspiration biopsy of the mass revealed that it was composed of fibrous connective tissue infiltrated with plasma cells, eosinophils, and neutrophils. Accordingly, a diagnosis of inflammatory pseudotumor of the liver was made. Marked reduction in the size of the lesion and a decrease of the levels of the CRP and ALP occurred without specific treatment. We emphasize the importance of ultrasonically guided aspiration biopsy in diagnosis of inflammatory pseudotumor of the liver without the need for surgery.

Biopsy, Needle↗
PubMed1991

Rheumatoid factors in patients with minimal change nephrotic syndrome.

Several immunological aberrations, especially T-cell abnormalities, have been shown to be involved in the development of the minimal change nephrotic syndrome (MCNS) although the responsible factors have not been identified. We studied rheumatoid factors (RF), thought to be a consequence of polyclonal B-cell hyperactivation, in sera from patients with MCNS using a sensitive fluorescence immunoassay (FIA). Significant increases of IgG and IgM RFs and marginal increase of IgA RF were observed during the nephrotic stages. Some patients still showed high titers of IgM RF in the early remission phases. The levels of RFs were normalized during complete remission. It was suggested that polyclonal B cell activation might be involved in the development of this disorder along with T cell abnormalities.

Adult↗
PubMed1991

Preparation of specific antisera against antigens from pharyngeal cells in patients with IgA nephropathy.

Rabbit antisera were produced against antigens obtained from pharyngeal cells of patients with IgA nephropathy (IgAN). Extracts of pharyngeal cells from patients with IgAN were frozen and thawed, and the supernatants were cocultured with fibroblasts (Vero and Hel cells). Pieces of renal biopsy specimens of the same patients were sectioned and centrifuged. The supernatants which contained IgA were incubated with the fibroblasts, and were stained with FITC-labeled anti human IgA antisera. Two positive (A and B) and one control Vero cell lines were destroyed and centrifuged. The precipitates were injected into rabbits, and rabbit antisera (A, B and control) were produced. Renal tissues from patients with IgAN and proliferative glomerulonephritis without IgA deposition (PGN) were stained with the FITC-labeled antisera. Positive stainings with FITC-labeled antiserum A was observed in 87% and that with FITC-labeled antiserum B in 55% of the patients with IgAN. No positive staining was detected with FITC-labeled control antiserum. There was also no positive staining with these antisera in renal tissues with PGN. The immunological specificity of the antisera was evaluated. It was found that these antisera did not react with complements components or immunoglobulins. The above findings suggested that some antigens from pharyngeal cells were deposited in the glomeruli from IgAN patients.

Animals↗
PubMed1991

[Effects of enflurane on the elastic properties of frog skinned skeletal muscle fiber under relaxed and rigor conditions].

We studied the effects of enflurane on the elastic property of the mechanical skinned fiber prepared from M. Semitendinosus of bullfrog. Longitudinal and lateral elastic properties of the skinned fibers were measured under relaxed and rigor conditions to clarify the effects of enflurane on actomyosin complex. Under the rigor condition, enflurane did not change the lateral elasticity of the fibers, but enflurane decreased the longitudinal elasticity. On the other hand, under the relaxed condition, enflurane did not change the elasticity. The results suggest that enflurane probably decreases the force of binding of cross-bridges to actin, which is one of the factors to reduce the maximal force.

Animals↗
PubMed1990

Microtubule-associated-protein (MAP) kinase activated by nerve growth factor and epidermal growth factor in PC12 cells. Identity with the mitogen-activated MAP kinase of fibroblastic cells.

Treatment of PC12 cells with either nerve growth factor (NGF), a differentiating factor, or epidermal growth factor (EGF), a mitogen, resulted in 7-15-fold activation of a protein kinase activity in cell extracts that phosphorylated microtubule-associated protein (MAP) 2 on serine and threonine residues in vitro. Both the NGF-activated kinase and the EGF-activated kinase could be partially purified by sequential chromatography on DEAE-cellulose, phenyl-Sepharose and hydroxylapatite, and were identical with each other in their chromatographic behavior, apparent molecular mass (approximately 40 kDa) on gel filtration, substrate specificity, and phosphopeptide-mapping pattern of MAP2 phosphorylated by each kinase. Moreover, both kinases were found to be indistinguishable from a mitogen-activated MAP kinase previously described in growth-factor-stimulated or phorbol-ester-stimulated fibroblastic cells, based on the same criteria. Kinase assays in gels after SDS/polyacrylamide gel electrophoresis revealed further that the NGF- or EGF-activated MAP kinase in PC12 cells, as well as the EGF-activated MAP kinase in fibroblastic 3Y1 cells resided in two closely spaced polypeptides with an apparent molecular mass of approximately 40 kDa. In addition, these MAP kinases were inactivated by either acid phosphatase treatment or protein phosphatase 2A treatment. These results indicate that MAP kinase may be activated through phosphorylation by a differentiating factor as well as by a mitogen. MAP kinase activation by EGF was protein kinase C independent; it reached an almost maximal level 1 min after EGF treatment and subsided rapidly within 30-60 min. On the other hand, NGF-induced activation of MAP kinase was partly protein kinase C dependent and continued for at least 2-3 h.

Adrenal Gland Neoplasms↗