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Biomedical subjects

A Kitamura

Publications and source records attributed to A Kitamura.

At least 109 records · Page 6Linked to original sources
PubMed1993

Renal fibroblasts are sensitive to growth-repressing and matrix-reducing factors from activated lymphocytes.

Various forms of nephropathy accompany interstitial fibrosis with lymphocytic infiltration. To probe the relationship between lymphocyte-derived factors and renal fibroblasts, we studied the effect of culture supernatant from lymphocytes stimulated by concanavalin A (ConASN) on the growth and matrix metabolism of rat kidney fibroblasts. 3H-thymidine incorporation and Northern analysis, respectively, revealed that ConASN repressed cell growth and the mRNA level of collagen type I, but dramatically elevated the steady-state expression of metalloproteinase transin/stromelysin. The growth inhibitor in ConASN was moderately heat-sensitive and less than 5 kD in molecular size, qualities that differed from those of transforming growth factor-beta (TGF-beta), IL-1 beta, IL-6, and tumour necrosis factor-alpha (TNF-alpha). The matrix regulatory factor in ConASN was highly heat-sensitive and more than 30 kD in size. Among several lymphokines tested, TNF-alpha produced the same effects as ConASN on the metabolism of extracellular matrix. We hypothesize that lymphocyte-derived factors have a significant role in the attenuation of renal fibrogenesis, as well as its progression, via inhibiting cell growth and matrix accumulation.

Animals↗
PubMed1993

[The intracuff pressure changes in N2O gas-barrier cuff made of a special material].

During inhalation anesthesia using N2O, the intracuff pressure has been reported to increase due to diffusion of N2O into the cuff. The excessive intracuff pressure may produce ischemia of the tracheal mucosa. In this study, the changes in the intracuff pressure of endotracheal tube with a cuff made of a material with high N2O gas-barrier properties were compared with those of the normal endotracheal tubes. Forty adult patients (16 males and 24 females) were anesthetized with oxygen 2 l.min-1, N2O 4 l.min-1 and isoflurane under controlled ventilation and they were divided into the following three groups according to the type of the endotracheal tube used: the tube with a standard cuff made by PORTEX Co. Ltd; the tube with a profile cuff (high volume cuff) made by PORTEX Co. Ltd; the tube with gas-barrier cuff made by TERUMO Co. Ltd. The changes of each intracuff pressure were recorded continuously for 180 minutes after cuff inflation. A marked increase of the pressure was observed after inhalation of N2O in standard and profile cuff groups. In gas-barrier cuff group, there was a tendency of increasing cuff pressure without a statistically significant difference. The present study suggests that the use of a cuff with a material of high N2O gas-barrier properties would be effective to prevent increased intracuff pressure by N2O diffusion, and this would be especially useful during long anesthesia and hypotensive anesthesia.

Adult↗
PubMed1993

Gene expression and regulation of HGF-SF.

Molecular cloning and characterization of cDNAs and genomic DNA for human HGF-SF revealed the expression pattern of the gene. Alternative use of splicing sites and processing/polyadenylation sites generates multiple mRNAs for human HGF-SF in a variety of tissues and cell lines. This alternative mRNA production may be regulated in a tissue-specific manner. Full-length HGF-SF is encoded by the 6.3 kb or 3.1 kb mRNA. A variant form of HGF-SF is encoded by the 1.5 kb mRNA which is generated by alternative splicing accompanied by the utilization of an alternative processing/polyadenylation site in an extra exon. The variant form consists of an N-terminal sequence and the first two kringles and acts as an antagonist of HGF-SF mitogenic activity. HGF-SF with a deletion of 5 amino acids in the first kringle is produced from an alternatively spliced mRNA. The deletion induces the change in the heparin-binding property of the protein. Analysis of responses of the HGF-SF mRNA during liver regeneration revealed that the HGF-SF gene is activated. The level of mRNA markedly increases in the rat liver, spleen and lung after administration of hepatotoxins. Characteristic regulatory elements, an IL6 response element and an NF-IL6 binding element, are present proximal to the major transcription initiation site in the human HGF-SF gene. These elements may be involved in the activation of the gene after liver injury. The potential autocrine role of HGF-SF in the acquisition of altered phenotypes was determined by introduction of the gene into target cells for HGF-SF. Autocrine production of the factor induces changes in cell properties from parental types to those obtained by the addition of exogenous factor.

Alternative Splicing↗
PubMed1992

Gene cloning and characterization of a novel extracellular ribonuclease of Bacillus subtilis.

An extracellular nuclease gene of Bacillus subtilis was cloned in the same organism by detecting the amplified enzyme activity, which was secreted from the transformant cells on an RNA-containing agar medium. An open reading frame encoding 289 amino acids was identified within the cloned fragment. The transcriptional initiation site was determined by nuclease S1 mapping and the promoter region showed similarity to the conserved recognition sequences for the E sigma A and/or E sigma E RNA polymerases. The production of the nuclease by the B. subtilis transformants greatly depends on the liquid medium used. SDS/PAGE analysis of the purified enzyme showed two adjoining bands of molecular mass about 32 kDa, and the NH2-terminal amino acid sequence analysis suggested that the NH2-terminal portion of the nuclease was subjected to a limited proteolysis after or during secretion. The nuclease was uniquely characterized as a Mg(2+)-activated ribonuclease which hydrolyzes RNA apparently nonspecifically into oligonucleotides with 5'-terminal phosphate. The deduced amino acid sequence of this enzyme shows no obvious similarity with other nuclease sequences.

Amino Acid Sequence↗
PubMed1992

Gene expression of metalloproteinase and its inhibitor in mesangial cells exposed to high glucose.

To clarify the roles of metalloproteinases and their inhibitor (TIMP) in diabetic glomerulopathy, we studied the effect of a high glucose concentration on the gene expression of metalloproteinase transin and TIMP as well as collagen type IV and laminin in cultured rat mesangial cells (MCs). In the high glucose group, collagen type IV, laminin, and TIMP mRNA levels were all elevated in a concentration-dependent manner, whereas transin expression was suppressed. Osmotic control of high glucose with mannitol selectively stimulated TIMP expression. We hypothesize that high glucose decreases matrix-degrading activity as well as increases matrix productivity in MCs.

Animals↗
PubMed1992

The diagnostic significance of anti-type II collagen antibody assay in rheumatoid arthritis.

An improved enzyme-linked immunosorbent assay (ELISA) for the detection of anticollagen antibodies in human serum has been developed. With the use of this method, antibodies against native human Type II collagen were detected in 22.7% of sera from 480 patients with rheumatoid arthritis (RA). The antibodies were found to be collagen type specific, showing no reaction with human Type I and Type III collagens. The antibodies appeared in high incidence during the early phase of the disease, and RA patients with involvement of a single joint, mono-articular arthritis, were often positive for anti-Type II collagen antibodies. In most of these patients, anti-Type II collagen antibodies preceded the appearance of rheumatoid factors. The antibodies were all negative in sera from patients with gout, osteoarthritis (OA) and non-arthritic diseases. Thus, anti-Type II collagen antibody assay may have diagnostic significance for RA patients, especially those in whom laboratory and clinical findings provide only minimal help in diagnosis.

Adult↗
PubMed1992

[A nested case-control study of risk factors for intracerebral hemorrhage and cerebral infarction classified by computed tomographic findings].

Risk factors for intracerebral hemorrhage (ICH) and cerebral infarction (CI), were studied by a prospective study of 7,390 men and women aged 40-69 without a history of stroke living in three rural populations in Japan. Baseline examinations were done for populations in Akita-Ikawa and Akita-Ishizawa in 1975-1979, and for Ibaraki-Kyowa in 1981-1987, and followed until 1989 for Akita-Ikawa and Ibaraki-Kyowa and 1987 Akita-Ishizawa. There were 246 stroke cases diagnosed by clinical criteria during the follow-up period in which 74 percent (n = 181) had data from computed tomography (CT) performed within three weeks of the onset. According to these CT-findings, 181 stroke were classified as 48 with ICH, 50 with CI in penetrating artery regions (penetrating artery infarction), 33 with CI in cortical artery regions (cortical artery infarction), and 31 with subarachnoid hemorrhage while there were 19 with stroke without any evident CT abnormality. Cortical artery infarction was further classified as embolic type (n = 17) and thrombotic type (n = 9) according to clinical findings of the onset and presence of possible embolic sources such as atrial fibrillation, congenital heart disease, myocardial infarction and heart valve diseases. Using a nested case-control design, risk variables at baseline examination were compared between 131 stroke cases, 48 ICH and 83 CI, with 655 controls matched for sex, age (+/- 3), and the follow-up year. Univariate analysis showed that high blood pressure was associated with all types of stroke. From conditional logistic regression analysis significant risk variables were found to be high blood pressure for ICH and penetrating artery infarction, while atrial fibrillation and ST-T abnormality in electrocardiogram (ECG) were risk variables for cortical artery infarction. Associations with hypertensive or arteriosclerotic changes in ocular fundus were stronger for penetrating artery infarction than ICH and cortical artery infarction. ST-T abnormality in ECG was associated with embolic type cortical artery infarction and high blood pressure was associated with the thrombotic type, although the number of cases were small. Compared to controls, cortical artery infarction showed a higher mean value of serum total cholesterol for thrombotic type cortical infarction, and lower mean values for embolic type and ICH, but none of them reached statistical significance. The present study also suggests that duration of hypertension varied with type of stroke. ICH may develop due to acute effects of hypertension, while penetrating artery infarction and cortical artery infarction develop by chronic effects of hypertension.

Adult↗
PubMed1992

[A new vein holder for side-to-side saphenous-coronary anastomosis].

A new vein holder for a side-to-side anastomosis between a vein graft and the coronary artery is described. The holder is consisted of two nerve hooks, and those distance is adjusted. The technique for creating the diamond anastomosis is also described.

Anastomosis, Surgical↗
PubMed1991

Structural organization and the transcription initiation site of the human hepatocyte growth factor gene.

The structural organization of the gene coding for human hepatocyte growth factor (hHGF) has been determined by seven overlapping lambda phage genomic clones including three clones that were previously characterized. The gene for hHGF spans about 70 kbp of DNA and consists of 18 exons separated by 17 introns. The coding sequence of hHGF consists of multiple putative domains that are homologous to those observed in plasminogen. These regions were found as separate exons in the gene, and the exon-intron arrangement was similar to that of plasminogen. These results suggest that the genes for hHGF and plasminogen have arisen through gene duplication events from an ancestral gene. The major transcription initiation site of the hHGF gene is located 76 bp upstream of the translational start codon as judged by S1 nuclease mapping and primer extension analyses. A TATA-like element was found 33 nucleotides upstream of the transcription initiation site. Two sequence elements, an interleukin 6 response element (CTGGGA) and a potential binding site for NF-IL6 (TGAGGAAAG), are located near the transcription initiation site. These sequence elements might be involved in the regulation of HGF gene expression.

Amino Acid Sequence↗
PubMed1991

Elevation of nerve growth factor synthesis by constitutive expression of v-src oncogene in cultured rat fibroblasts.

Rat fibroblast 3Y1 cells transformed by Rous sarcoma virus (RSV) or transfected with the v-src gene showed a highly constitutive v-src gene expression. Simultaneously, marked increases in the cellular level of nerve growth factor (NGF) mRNA and NGF content in the culture medium were observed. The levels of NGF mRNA and NGF secreted into the medium were correlated with the expression level of v-src mRNA gene in both transformants and control 3Y1 cells. These results suggest that v-src gene expression is relevant to regulation of NGF synthesis in rat 3Y1 fibroblasts.

Animals↗
PubMed1991

Calcium intake and blood pressure in seven Japanese populations.

The relation between dietary calcium and blood pressure was examined in 1,928 men, ages 40-69 years, from five geographic and two occupational populations in Japan. Dietary calcium intake was estimated using 24-hour dietary recall in systematic samples of participants of population-based cardiovascular surveys from 1983 to 1987. The means of daily calcium intake of the study populations ranged from 449 to 695 mg, approximately 300 mg lower than the recommended US dietary calcium intake. Linear regression analyses were used to examine the relation between dietary calcium and blood pressure within each population, controlling for age, body mass index, alcohol consumption, and sodium intake. Total calcium intake was inversely associated with the systolic blood pressure level in each population, and the pooled estimate of the regression coefficients for millimeters of mercury of blood pressure per 100-mg increase in calcium intake was -0.54 (95% confidence interval -0.89 to -0.19). The inverse association between calcium intake and diastolic blood pressure was less consistent, and the pooled estimate did not reach statistical significance (-0.10, 95% confidence interval -0.34-0.14). Inverse associations existed for both dairy and nondairy food sources of calcium when analyzed separately, and the association was significant only for dairy calcium. Although a causal relation between dietary calcium and blood pressure cannot be established, these results suggest a possible public health implication in Japan of increasing calcium intake for the prevention and control of hypertension, where average dietary calcium intake is low.

Adult↗
PubMed1991

An alternatively processed mRNA generated from human hepatocyte growth factor gene.

We recently reported the isolation and sequencing of cDNA for human hepatocyte growth factor (hHGF) [Miyazawa, K., Tsubouchi, H., Naka, D., Takahashi, K., Okigaki, M., Arakaki, N., Nakayama, H., Hirono, S., Sakiyama, O., Takahashi, K., Gohda, E., Daikuhara, Y. & Kitamura, N. (1989) Biochem. Biophys. Res. Commun. 163, 967-973]. In the present study, we report the sequence of another cDNA clone for a shorter form of hHGF mRNA. Comparison of the sequence with that of the hHGF cDNA revealed that the two sequences are identical in their 5' ends up to 865 nucleotides downstream from the translation-initiation site, then completely diverge from each other. By Northern blot analysis, the hHGF-related 1.5-kb mRNA, which corresponded to the newly isolated cDNA variant, was identified in human placenta. Sequence analysis of a human genomic HGF clone showed that the diverged 3'-terminal portion of the mRNA is generated by alternative RNA-processing events utilizing a specific exon. The mRNA could encode a short hHGF molecule of 290 amino acids corresponding to the N-terminal portion of hHGF which consists of 728 amino acids. In order to examine the effect of the predicted translation product on hepatocyte growth, an expression plasmid for the cDNA variant was constructed and transfected into Cos cells. Immunoblotting analysis showed that the transfected Cos cells produced a protein of about 33 kDa. The protein product did not stimulate DNA synthesis by rat hepatocytes in primary culture.

Amino Acid Sequence↗
PubMed1991

Effective chemotherapy for abdominal desmoid tumor in a patient with Gardner's syndrome. Report of a case.

Desmoid tumors are rare, but not in patients with Gardner's syndrome. Although standard treatment is wide surgical excision, we prescribed chemotherapy for a 30-year-old woman with intra-abdominal desmoids, a complication after subtotal colectomy for the treatment of familial polyposis coli. Exploratory laparotomy revealed that the desmoids were not resectable. Chemotherapy with combinations of vincristine, azathioprine, cyclophosphamide, and prednisone was prescribed for over 3 months, and a partial regression of the tumors occurred. Two years after the initiation of the chemotherapy, complete regression of tumors was achieved with cyclophosphamide and prednisone. Surgical excision, irradiation, and chemotherapy treatments are discussed.

Abdominal Neoplasms↗
PubMed1991

The relation of body fat distribution and body mass with haemoglobin A1c, blood pressure and blood lipids in urban Japanese men.

The relation of body fat distribution and body mass with haemoglobin A1c, blood pressure and blood lipids were examined in 874 men aged 40 to 59 not taking medication for diabetes mellitus and who worked for an urban company in Japan. Body fat distribution was measured by the waist hip circumference ratio. Body mass was estimated by Quetelet index. Haemoglobin A1c was measured from casual venous blood samples by high-pressure liquid chromatography. Measurement of haemoglobin A1c was validated by a 75 g oral glucose tolerance test conducted in a 7% sample. There was a dose-response relation between waist-hip ratio and haemoglobin A1c concentration while the relation between body mass index and haemoglobin A1c was not evident. Using linear regression to control for age, serum total cholesterol, usual alcohol consumption, cigarette smoking and body mass index, the positive association between waist-hip ratio and haemoglobin A1c remained significant (p = 0.02). This was not true for the positive association between body mass index and haemoglobin A1c (p = 0.32). Both waist-hip ratio and body mass index were positively associated with blood pressure and serum total cholesterol, and inversely associated with HDL-cholesterol. The associations of waist-hip ratio with blood pressure and blood lipids were significant after controlling for body mass index. Therefore, the waist-hip ratio is a correlate of both glucose abnormalities and known coronary risk factors in urban Japanese men even when body mass is controlled for.

Adult↗
PubMed1991

Stereotactic Aqua-Stream and Aspirator in the treatment of intracerebral hematoma. An experimental study.

The efficacy of the Stereotactic Aqua-Stream and Aspirator (SAS&A) was experimentally investigated by using hematoma models in the test tube and in gelatin. Even a solid hematoma can be crushed by the water jet and aspirated easily. The greater the positive pressure of the water jet and the negative pressure of suction, the stronger the ability to remove clots. A water jet pressure of 10-20 kg/cm2 and a suction pressure of 100-200 mm Hg were sufficient to remove experimental clots from the test vessels. When the SAS&A was operated in the brain of dogs with a water jet pressure of 20 kg/cm2 and a suction pressure of 200 mm Hg, aspirated brain tissue was less than 15 mg/min in weight, and histological brain injuries were observed only in the area less than 2 mm from the window of the probe, indicating that the procedure with the SAS&A would be relatively atraumatic. We conclude that these observations indicate that the SAS&A can be safe and extremely useful for removal of hypertensive intracerebral hematomas, even in the acute stage.

Animals↗
PubMed1991

Use of a triple protease-deficient mutant of Bacillus subtilis as a host for secretion of a B. subtilis cellulase and TEM beta-lactamase.

The mature portion of the TEM beta-lactamase (BLA) gene (bla) derived from pBR322 was fused with the promoter and signal region of Bacillus subtilis cellulase (BSC) gene (bsc), and the productivity was compared with that of the cloned native bsc gene, using a wild-type B. subtilis strain and a strain deficient in three proteases (i.e., extracellular serine protease, extracellular neutral protease, and the major intracellular serine protease) as hosts. The effects of the sen, sacQ, and prtR genes, carried on the same plasmids, were tested as for the productivities of BSC and BLA. The production of BSC was increased 9-fold by using the combination of the triple-protease deficient strain and the sacQ gene, compared with that by using the wild-type strain as a host, and no degradation of BSC was observed in the triple-protease deficient strain. On the other hand, though the production of the BSC-BLA fusion protein increased 2.5-fold in the triple-protease deficient strain, the BLA activity was decreased after the cell reached the stationary phase of growth, possibly due to some proteolysis. These observations show different sensitivity of secretary proteins to cellular proteases, and suggest that BLA is decomposed by remaining minor proteases.

Amino Acid Sequence↗