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Biomedical subjects

S Kawamura

Publications and source records attributed to S Kawamura.

At least 19 recordsLinked to original sources
PubMed1995

Regulation of rhodopsin phosphorylation by a family of neuronal calcium sensors.

Recoverin is a calcium sensor that regulates rhodopsin phosphorylation in a calcium-dependent manner. Cloning experiments indicate the presence of a numerous gene family, called the NCS family, encoding recoverin-like proteins expressed predominantly in neurons. Here, we report the cloning of three novel NCS genes, and demonstrate that at least six distinct members of the NCS family (including recoverin, S-modulin, vilip 1, NCS-1, Ce-NCS-1, and Ce-NCS-2) specifically inhibit rhodopsin phosphorylation. The presence of species homologues within the NCS family suggests that this function might be shared by at least 12 (out of 18) NCS proteins. Recent studies indicate that recoverin inhibits rhodopsin phosphorylation by directly regulating rhodopsin kinase, a G protein coupled receptor kinase (GRK). Since several NCS proteins are found in neurons throughout the entire nervous system, they may regulate other members of the GRK family. Together, our data suggest a general role for NCS proteins in the regulation of calcium-dependent phosphorylation in the nervous system.

Amino Acid Sequence↗
PubMed1995

Paralogous origin of the rhodopsinlike opsin genes in lizards.

Rhodopsinlike opsins constitute a distinct phylogenetic group (Yokoyama 1994, Mol. Biol. Evol. 11:32-39). This RH2 group includes the green-sensitive opsins in chicken and goldfish and the blue-sensitive opsin in a nocturnal lizard gecko. In the present study, we isolated and sequenced the genomic DNA clones for the RH2 opsin gene, rh2Ac, of the diurnal lizard Anolis carolinensis. This single-copy gene spans 18.3 kb from start to stop codons, making it the longest opsin gene known in vertebrates. Phylogenetic analysis strongly suggests that rh2Ac is more closely related to the chicken green opsin gene than to the gecko blue opsin gene. This gene tree differs from the organismal tree, where the two lizard species should be most closely related, implying that rh2Ac and the gecko blue-sensitive opsin genes have been derived from duplicate ancestral genes.

Amino Acid Sequence↗
PubMed1995

Expression of sialylparagloboside in a case of liposarcoma: aberrant glycosylation in tumors arising in adipose tissues.

Gangliosides of liposarcoma, lipoma and lipids from omental tissues were analyzed. By immunostaining after thin layer chromatography, gangliosides of liposarcoma were identified as GM3, sialylparagloboside and GD3, whereas those of lipoma were GM3 and GD3, and those of fat in omental tissues were GM3, GD1a, GD3 and some unknown ones. Expression of sialylparagloboside is thought to be very rare.

Adipose Tissue↗
PubMed1995

Basophilic degeneration of the myocardium: histological, immunohistochemical and immuno-electronmicroscopic studies.

We studied basophilic degeneration of heart muscle cells in 100 consecutive autopsies (74 males, 26 females). Except for two infants, the age of individuals whose tissue was studied ranged from 10 to 90 years (mean age, 68.3). Using histochemical and immunohistochemical methods, we found the frequency and extent of basophilic degeneration and the materials in type IV glycogenosis (Andersen's disease) were reactive to monoclonal antibodies raised against polyglucosan extracted from the myocardium of a patient with Lafora's disease. Basophilic degeneration was found in 98% of the entire study population and in 100% of those aged over 60. The reactivity for polyglucosan became more intense after diastase digestion. Immuno-electronmicroscopy using an immunogold method showed that the fibril-like structures of basophilic degeneration were specifically labelled by the monoclonal antibodies to polyglucosan.

Adolescent↗
PubMed1995

Incidence and distribution of isolated atrial amyloid: histologic and immunohistochemical studies of 100 aging hearts.

The incidence and anatomic distribution of isolated atrial amyloid (IAA) in 100 aging hearts were studied histologically and immunohistochemically using antibodies against alpha-human-atrial natriuretic peptide (alpha-ANP), human transthyretin (TTR) and human amyloid P component (AP). Ninety-one of 100 hearts (91%) had amyloid deposits in the atria. Amyloid deposits in all 91 hearts reacted with alpha-ANP and AP antisera, and in four hearts other amyloid deposits that reacted with TTR antiserum were coincidentally seen in the atria. The prevalence of IAA deposition, using a semiquantitative evaluation, was significantly higher in the hearts from patients over 80 years of age, from women, those weighing over 450 g, with a thickened left ventricular wall (> 1.4 cm) and with multiple myocardial scars. IAA deposition showed a significant distribution in the auricle and left atrium; it was located mostly in the interstitium of the subendocardial layer and the subendocardial myocardium. These results indicate that IAA occurs more frequently than previously appreciated in the elderly and in patients with certain cardiac disorders.

Aged↗
PubMed1995

[Isolation of Cryptococcus neoformans from environments (pigeon excreta) in Nagasaki].

Cryptococcosis is one of the serious deep-seated mycoses in immunocompromised patients, especially those with AIDS. Cryptococcus neoformans ordinarily lives in natural environments such as soil and reproduces in pigeon excreta. It spreads in the air and infects human by inhalation. We isolated C. neoformans from pigeon excreta in hospitals, private houses, parks in Nagasaki from October to December in 1994. C. neoformans was isolated from 4 of 8 samples (50%) of pigeon excreta and the isolation rate increased to 80% (4/5) if they were weathered excreta. Two patients with pulmonary cryptococcosis occurred in the last two years in the area where C. neoformans was isolated during that period. Epidemiological studies of clinical isolates and environmental isolates are important to determine its origin of infection and the route of transmission.

Animals↗
PubMed1995

Cloning of the gene encoding DNA binding protein HU from Bacillus stearothermophilus and its expression in Escherichia coli.

The gene (hbst) encoding the DNA binding protein HU from Bacillus stearothermophilus was cloned, with the Bacillus subtilis HU gene (hbsu) as a hybridization probe. The nucleotide sequence, which contains a ribosome binding site, a transcriptional termination signal, as well as the coding region, was analyzed by the dideoxy chain-termination method. The deduced amino acid sequence of an open reading frame was perfectly matched with that of B. stearothermophilus HU (BstHU) determined by the protein chemical methods [M. Kimura and K. S. Wilson, J. Biol. Chem., 258, 4007-4011 (1983)]. The gene, hbst, was overexpressed using the expression vector pET-5a in Escherichia coli, and the recombinant HU protein (r-BstHU) was purified to be homogeneity by heparin-agarose column chromatography followed by ion-exchange column chromatography on S-Sepharose. The recombinant protein thus obtained had a circular dichroism spectrum identical to that of the authentic protein and bound to DNA to the same extent as the authentic protein.

Amino Acid Sequence↗
PubMed1995

Development of Babesia gibsoni in the salivary glands of the larval tick, Rhipicephalus sanguineus.

The development of Babesia gibsoni in the salivary glands of larval Rhipicephalus sanguineus ticks was morphologically studied for 4 days of feeding of tick on rabbits. Babesia gibsoni showed two forms (sporont and sporozoite) in the budding process. Sporozoites were formed in the acinar cells of salivary glands and released from the hollow cytoplasmic area of these cells by day 4 of feeding. The morphology of B. gibsoni in the salivary glands of R. sanguineus shows a close similarity to those of B. gibsoni in Haemaphysalis longicornis.

Animals↗
PubMed1995

Development of intestinal flora of human-flora-associated (HFA) mice in the intestine of their offspring.

Development of intestinal flora in newborn human-flora-associated (HFA) mice was compared with that in newborn conventional (CV) mice. Facultative anaerobes were detected from the first day after birth in both CV and HFA mice but anaerobes were not detected in the first week. Anaerobes rapidly increased from the 2nd week after birth and became predominant in newborn intestine. Most of the intestinal bacteria in adult CV and HFA mice were colonized in the intestine of CV and HFA mice, respectively, within 3 weeks after birth. The human intestinal flora established in the intestine of HFA mice finally reproduced without any remarkable change in composition in the intestine of newborn HFA mice. The development of intestinal flora in HFA mice was similar to that in CV mice but not that in human infants. These results indicated that human flora associated in HFA mice could be transferred from mothers to their offspring although HFA mice could not simulate the development of intestinal flora of the human infant.

Adult↗
PubMed1995

[Clinical significance of proliferating cell nuclear antigen (PCNA) and argyrophilic nucleolar organizer region (AgNOR) in testicular tumors].

BACKGROUND: Proliferative potential of testicular tumor was assessed by immunohistochemistry using anti-proliferating cell nuclear antigen (PCNA) monoclonal antibody and silver staining of argyrophilic nucleolar organizer region (AgNOR), and the results were compared with clinical course. METHODS: Fourty-five patients with testicular tumor and 10 normal testicles were investigated. All specimens were fixed with 10% buffered formaliun within 24 hours. The interval between patient's recognition of testicular swelling for the first time and the date for operation was designated as M (months), and the specimen weight was designated as g (gram). Growth rate of the primary tumor was estimated roughly by g/M. RESULTS: PCNA positive rates in seminomas, non-seminomas and normal testes were 70.5 +/- 19.1% (mean +/- S.D.), 80.4 +/- 10.5% and 17.7 +/- 7.8%, respectively. PCNA positive rate in stage I seminoma (64.4 +/- 19.9%) was significantly lower than stage II and III seminoma (83.6 +/- 7.3%) (p < 0.05), but not significant between stage I non-seminoma and stage II, III non-seminoma. The mean numbers of AgNOR per nucleus in seminomas, non-seminomas and normal testes were 8.09 +/- 1.35 (mean +/- S.D.), 6.89 +/- 1.43, 4.18 +/- 1.60, respectively and significantly higher in testicular tumors than normal testes. There were, however, no significant difference between their clinical stages. Logarithmic significant correlation was observed between PCNA positive rate and the growth rate in primary lesion, but no correlation was found between mean number of AgNOR per nuclei and the growth rate. Of the 10 patients with stage I non-seminomas received surveillance policy, four relapsed. Of the 10 patients, 4 of the 6 patients with higher than 75% PCNA positive rate relapsed, whereas, none of the 4 patients with lower than 75% PCNA positive rate relapsed. There were no significant correlation between PCNA positive rate and number of AgNOR. CONCLUSION: PCNA is more accurate indicator of growth potential in testicular tumor than AgNOR and may predict recurrence in stage I non-seminomatous testicular tumor patients followed by surveillance policy.

Carcinoma, Embryonal↗
PubMed1995

[Acute pulmonary embolism after radical operation for renal cell carcinoma with vena caval extension: a case cured by thrombolytic therapy].

A 54-year-old man was hospitalized for a right renal tumor with intraluminal extension into the vena cava. He underwent radical nephrectomy with thrombectomy and regional lymphadenectomy. On the 8th postoperative day, he suddenly complained of dyspnea with tachypnea and cyanosis. Arterial blood gas analyses under an oxygen flow of 4L/min revealed PaO2 32.1 mmHg. Pulmonary angiography revealed filling defects in the right main pulmonary artery and left descending branch. Under the diagnosis of acute pulmonary embolism, thrombolytic and anti-coagulation therapy was performed and the patient recovered from the disease. We should be aware of pulmonary embolism as a postoperative complication of urological surgery.

Acute Disease↗
PubMed1995

[Prominent subepithelial deposits detected on 2nd renal biopsy in a boy with membranoproliferative glomerulonephritis type I: a case report].

The first renal biopsy of a 7-year-old boy with microscopic hematuria, hypocomplementemia (CH50 20 U/ml, C3 33 mg/dl, C4 13 mg/dl) and otherwise normal renal function revealed lobular, but not diffuse, expansion of glomerular mesangial areas showing mild to marked mesangial cell proliferation and thickening of the capillary walls with double contours as seen on light microscopic examination. Granular C3 deposition along the capillary wall and in the mesangium was observed on immunofluorescent microscopy. Further, electron microscopy showed subendothelial dense deposits and circumferential mesangial interposition. Thus, he was diagnosed as membranoproliferative glomerulonephritis (MPGN) type I. Thereafter, high-dose, alternate-day administration of prednisolone was started. A few months after treatment, microscopic hematuria disappeared and hypocomplementemia improved. The second renal biopsy at 11 years of age showed markedly decreased mesangial cell proliferation and subendothelial dense deposits. However, C3 deposition still persisted and subepithelial dense deposits had increased in number prominently at this time. Whether MPGN type III is a distinct disease entity or a variant of MPGN type I has not yet been established. The morphological changes in this reported case might justify the notion that MPGN type III is a variant form of MPGN type I.

Adolescent↗
PubMed1995

[Intrascrotal epidermal cyst: a case report].

A 37-year-old male visited our hospital complaining of right scrotal mass formation. An elastic hard, fist-size mass was found in the right scrotum. Under the diagnosis of an intrascrotal benign tumor, the mass was removed. The tumor had no relation to the testis or epididymis. The surgical specimen weighted 220 g and measured 13 x 8 x 8 cm in size. Histopathological diagnosis was epidermal cyst of the intrascrotum. Epidermal cyst of the intrascrotum is a rare disease and only 13 cases have been previously reported in Japan.

Adult↗
PubMed1995

A case report of nephrotic syndrome associated with rifampicin therapy.

We describe nephrotic syndrome occurring in a 53-year-old male patient on continuous rifampicin (RFP) therapy for pulmonary tuberculosis. After the pulmonary tuberculosis was improved by chemotherapy that included RFP, administration of Isoniazid and RFP was continued. After 16 weeks, he suddenly developed nephrotic syndrome, but never developed acute renal failure. He was admitted to hospital and renal biopsy was performed revealing minor glomerular abnormalities and few interstitial changes in light microscopy. No positive immunofluorescent microscopic findings were obtained without fibrinogen. Thus, minimal change nephrotic syndrome (MCNS) was diagnosed. In contrast, electron microscopy showed several injurious glomerular changes, such as the elevation of the endothelial layer, local widening of the subendothelial space which was filled with fine granular or fibrillar materials, irregularity of the endothelial investment, swelling or shrinkage of the endothelial cells, compatible with those seen in many diseased conditions supposedly caused by clinical or subclinical localized intravascular coagulation. Discontinuation of RFP administration completely relieved the patient of MCNS with the aid of predonisolone therapy. Thus, this patient might not have been a case of incidental, but rather drug (RFP)-induced MCNS.

Humans↗
PubMed1994

In vivo effects of the Ca2+ entry blocker nilvadipine on brain surface microvessels in rats.

The effects of the Ca2+ entry blocker nilvadipine on the diameter of the brain surface microvessels of rats were studied in vivo using intravital fluorescence microscopy and a closed cranial window technique under an intracranial pressure of 5-7 mmHg. Intravenous Na(+)-fluorescein was used as a blood-brain barrier (BBB) and vessel marker. The BBB function, as determined by the barrier marker, remained intact during the entire observation period. Nilvadipine (10(-10)-10(-6)M) and/or vehicle were dissolved in artificial cerebrospinal fluid (CSF). Superfusion of the brain surface with artificial CSF with and without vehicle had no effect on vessel diameters. Nilvadipine dilated pial arterioles in a dose-dependent manner. The arterioles were dilated significantly at concentrations of > or = 10(-9)M when compared with resting diameters. The diameters of venules were not affected by nilvadipine. The results suggest a possible mechanism for the nilvadipine-induced increase in the cerebral blood flow under physiological conditions.

Animals↗
PubMed1994

Dual staining methods for carbohydrates using lectin-gold silver techniques.

Three dual staining methods were established for the histochemical detection of saccharide residues and acidic groupings of carbohydrates in light microscopy. The first method consisted of combined lectin-gold silver (LT-G-S) and alcian blue (AB) pH 1.0 techniques, whereas the second staining technique was composed of LT-G-S and AB pH 2.5 procedures. These two techniques were found to color saccharide residues and acidic groupings of carbohydrates in black and blue shades respectively, which exhibited a high contrast between the both. The third methods, LT1-G-S-LT2-PO-DAB techniques, yielded reaction products of blackish and yellowish brown shades, which represented the localizations of two different saccharide residues in one and the same section. According to the results of the experimental and control procedures, the present three dual staining methods are believed to be reliable, reproducible and unusually useful for light microscopic histochemical studies on acidic and non-acidic carbohydrates.

Animals↗