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Biomedical subjects

Y Kobayashi

Publications and source records attributed to Y Kobayashi.

At least 181 records · Page 10Linked to original sources
PubMed2001

Diverse chalcone synthase superfamily enzymes from the most primitive vascular plant, Psilotum nudum.

Psilotum nudum Griseb is a pteridophyte and belongs to the single family (Psilotaceae) of the division, Psilophyta. Being the only living species of a once populated division, P. nudum is the most primitive vascular plant. Chalcone synthase (CHS; EC 2.3.1.74) superfamily enzymes are responsible for biosyntheses of diverse secondary metabolites, including flavonoids and stilbenes. Using a reverse transcription-polymerase chain reaction strategy, four CHS-superfamily enzymes (PnJ, PnI, PnL and PnP) were cloned from P. nudum, and heterologously expressed in Escherichia coli. These four enzymes of 396-406 amino acids showed sequence identity of > 50% among themselves and to other higher-plant CHS-superfamily enzymes. PnJ and PnP preferred p-coumaroyl-CoA and isovaleryl-CoA respectively, as starter CoA and catalyzed CHS-type ring formation, indicating that they are CHS and phlorisovalerophenone synthase, respectively. On the other hand, PnI and PnL preferred cinnamoyl-CoA as starter CoA and catalyzed stilbene synthase-type cyclization and thus were determined to be pinosylvin synthases (EC 2.3.1.146). In addition, PnE, which uniquely contains a glutamine in place of otherwise strictly conserved histidine, had no apparent in vitro catalytic activity. Phylogenetic analysis indicated that these P. nudum clones form a separate cluster together with Equisetum arvense CHS. This cluster of pteridophytes is located next to the cluster formed by pine (gymnosperm) enzymes, in agreement with their evolutionary relationships. Psilotum nudum represents a plant with the most diverse CHS-superfamily enzymes and this ability to diverge may have provided a survival edge during evolution.

Acyltransferases↗
PubMed2001

The formation of capsule and septum in human hepatocellular carcinoma.

The formation of fibrous capsule around the cancer nodule and of the septum in the tumor is frequently observed with the development of hepatocellular carcinoma (HCC). We aimed to clarify how the capsule and septum were formed during the growth of HCC. Liver samples surgically resected from 25 patients with HCC were studied with in situ hybridization for type-I, -III, and -IV procollagen. Type-I and -III procollagen-expressing cells, mostly alpha-smooth muscle actin (SMA)-positive, were increased in the fibrous capsule and in the septum between HCC nodules. These cells were also found at the invasion front of HCC and around the necrotic cancer tissues. Type-IV procollagen gene expression was mainly observed in mesenchymal cells localized in both HCCs and non-cancerous liver. Cancer cells or hepatocytes did not express any of these procollagen genes. The present study reveals that the capsule and septum are mainly formed by alpha-SMA-positive mesenchymal cells at the interface between two different tissues (e.g., cancer nodule vs non-cancerous liver or another cancer nodule). The wound healing occurs even in HCC. The capsule formation may result from interaction between tumor and host liver and interfere the growth and invasion of HCC.

Actins↗
PubMed2001

Developmental changes in cyclooxygenase mRNA expression in the kidney of rats.

Prostaglandins, synthesized by cyclooxygenase (COX), regulate renal hemodynamics and also epithelial water and solute transport. To determine whether COX mRNA expression changes with age, we studied expression in renal medulla and in cortex in developing rats at various ages. We also examined age-related changes in COX mRNA expression induced by lipopolysaccharide (LPS). COX mRNA was quantitatively analyzed in a real-time polymerase chain reaction (PCR) with dual-labeled fluorogenic probes. COX-1 mRNA expression did not change with age in cortex or medulla. COX-2 mRNA expression was highest in 1-week-old rats and lowest in 4- and 8-week-old rats. Lipopolysaccharide treatment did not alter COX-1 mRNA expression in infantile or adult rats. In adults, LPS at 1, 5, and 10 mg/kg induced COX-2 mRNA expression in renal medulla; the higher doses, 5 and 10 mg/kg, induced COX-2 expression in cortex. In infantile rats, COX-2 mRNA, already high in the unmanipulated state, was further increased by only 1 mg/kg LPS in both renal cortex and medulla. Age-related changes in the expression of COX-2 mRNA might be responsible for changing physiologic characteristics of renal function during postnatal development in rats, and may be important in renal cortical development.

Aging↗
PubMed2001

Acute reversible renal failure with macroscopic hematuria in Henoch-Schönlein purpura.

A Japanese girl aged 5 years 4 months developed macroscopic hematuria and acute renal failure (ARF) 8 days before the appearance of purpura rash. A renal biopsy undertaken during the acute phase of illness revealed many red blood cells in the tubular lumina with no apparent glomerular lesions. ARF showed improvement without dialysis therapy. A second renal biopsy was performed 2.5 months later because of the prolonged proteinuria and hematuria. Sclerotic change and crescent formation were demonstrated in 30% and 20% of glomeruli, respectively. Red blood cell casts in the tubular lumina were completely resolved. It is likely that the tubular change was involved in the development of ARF at the onset of illness. Although ARF during or after episodes of macroscopic hematuria has been observed in IgA nephropathy, it may occur as an uncommon complication in Henoch-Schönlein nephritis, which is a common glomerulonephritis in children.

Acute Kidney Injury↗
PubMed2001

Elevated serum vascular endothelial growth factor and basic fibroblast growth factor levels in patients with thymic epithelial neoplasms.

Neovascularization, an essential event for the growth of solid tumors, is regulated by a number of angiogenic factors, among which vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF), are considered to exert potent angiogenic activity. In this study, we investigated whether serum VEGF and bFGF levels could be predictors of the development and extension of thymic epithelial neoplasms. The subjects of this study were 37 patients with thymoma, 6 with thymic carcinoma, and 23 healthy volunteers. Serum samples were collected before clinical treatment. Serum VEGF levels were significantly (P < 0.05) elevated in the patients with thymic carcinoma (1,080 +/- 1,185pg/ml) compared with those in the healthy volunteers (407 +/- 589 microg/ml). Serum bFGF levels were also significantly (P < 0.05) elevated in the patients with thymic carcinoma (2740 +/- 631 pg/ml) compared with those in the healthy volunteers (1728 +/- 1,192 pg/ml). However, the serum VEGF and bFGF levels did not significantly differ between the patients with thymoma and the healthy volunteers. Serum VEGF and bFGF levels did not significantly differ according to the stage and pathological subtype of thymoma. Moreover, there was no correlation between the serum levels of VEGF and those of bFGF. Thus, while serum VEGF and bFGF levels may serve as markers for thymic epithelial tumors, it is unlikely that circulating VEGF and bFGF could be used as markers for assessing the progression of thymoma tumors.

Adult↗
PubMed2001

Postoperative evaluation of pylorus-preserving procedures compared with conventional distal gastrectomy for early gastric cancer.

We evaluated postoperative function in 98 patients who underwent surgery for early gastric cancer between 1995 and 1998 to compare the results of pylorus-preserving procedures to those of conventional distal gastrectomy with Billroth I (B-I). The pylorus-preserving procedures included endoscopic mucosal resection (EMR), performed in 12 patients; local resection (Local), performed in 14 patients; segmental resection (Seg), performed in 8 patients; and pylorus-preserving gastrectomy (PPG), performed in 19 patients. B-I was performed in 45 patients. The nutritional status and serum albumin (Alb) levels after PPG, the hemoglobin (Hb) levels after EMR, Local, and PPG, and the present/preoperative body weight ratios after EMR, Local, Seg, and PPG were superior to those after B-I. The time before oral intake was recommenced after EMR and Local, the volume of oral intake tolerated after EMR, Local, Seg, and PPG, and the postoperative hospital stay after EMR were all superior to those after B-I. Moreover, significantly fewer patients suffered reflux symptoms after EMR, Local, and PPG, abdominal fullness after EMR, and early dumping syndrome after EMR, Local, and PPG than after B-I. There was also less evidence of gastritis after EMR, Local, and PPG, and of bile reflux after EMR, Local, and PPG, than after B-I. These findings indicate that pylorus-preserving procedures may result in a better postoperative quality of life for selected patients with early gastric cancer.

Adult↗
PubMed2001

A longitudinal study for femoral neck bone mineral density increases in premenopausal caddies using dual-energy X-ray absorptiometry.

This longitudinal study examined whether bone mineral density (BMD) of the lumbar spine and proximal femur is maintained in premenopausal caddies (n = 6; mean age 37.8 years) in comparison with desk workers (n = 6; mean age 40.8 years) at the same golf club. BMD was followed for 12 months using dual-energy X-ray absorptiometry (DXA) and bone metabolic markers and athletic ability were also examined. Longitudinally, for caddies, the change per year in BMD of the lumbar spine was +0.009 g/cm2, while that of the proximal femur was +0.022 g/cm2, showing significant differences (P < 0.05 by signed-rank test). Their athletic ability, in terms of leg-press power, also significantly increased, whereas bone metabolic markers, such as serum alkaline phosphatase, 1,25-(OH), vitamin D3, parathyroid hormone and the deoxypyridiniline/creatinine ratio, did not show significant changes. For desk workers, the change per year in BMD of the lumbar spine was +0.011 g/cm2, while that of the proximal femur was -0.006 g/cm2. Their BMD, athletic ability and bone metabolic markers did not show significant changes. These findings support the results of our previous study, that premenopausal women can achieve continuous gain in femoral neck BMD by regular intense athletic activity, and suggest that this is also true by the continuous extensive walking of golf caddies.

Absorptiometry, Photon↗
PubMed2001

Clinical observation and treatment of leptospirosis.

The epidemiological and clinical observations of 240 patients with Weil's disease and 10 patients with canicola fever, and these observations in two epidemics of canicola fever, are presented. Early diagnosis is most important for the prognosis of patients with the severe form of leptospirosis. It depends on the clinical features, clinical laboratory findings, and the epidemiological situation. The most characteristic clinical signs for early diagnosis were febrile illness of sudden onset, severe general malaise, muscular pain, and conjunctival congestion. Proteinuria, leukocytosis with neutrophilia, and raised erythrocyte sedimentation rate were the most indicative clinical laboratory findings for early diagnosis. Although jaundice and hemorrhage are the most important signs of the severe form of leptospirosis, Weil's disease, these are rarely useful in early diagnosis. Of a variety of antibiotics used, penicillins and cephems had the lowest minimal inhibitory concentration against leptospires. However, it became apparent from basic studies in vitro and in vivo that streptomycin showed the best bactericidal action against leptospires and that it was the most effective anti-leptospiral antibiotic. Gentamicin, tobramycin, and isepamicin are also effective as alternatives to streptomycin. Although penicillins, cephems, tetracyclines, and macrolides are also effective for the treatment of leptospirosis, when these antibiotics with inadequate bactericidal activity are used for the treatment of the disease, long-term therapy with sufficiently large doses may be required from an early stage of the disease until the appearance of antibodies.

Animals↗
PubMed2001

Discovery of the causative organism of Weil's disease: historical view.

On January 20, 1915, Inada and Ido announced the discovery of the causative agent of Weil's disease. Subsequently, on February 13, 1915, they published the first paper on the discovery of the causative organism (a new species of Spirochaeta) of Weil's disease. Besides discovering the causative organism of the disease, Inada and colleagues clarified the pure culture in medium, and determined the source and route of the infection, its pathology and morbid anatomy; the distribution of the organism in various organs and tissues; the excretion of the spirochete, and its division, filterability, and morphological characteristics; and the clinical picture, laboratory findings, diagnosis, prophylaxis, and treatment of the disease. These studies were conducted by Inada, Ido, Kaneko, Hoki, and Ito, in the years 1914 to 1915. In the early investigation of leptospirosis, Inada and colleagues played a prominent part. We would like to remember these remarkably complete and definitive original achievements on leptospirosis made by Inada and colleagues.

Animals↗
PubMed2001

The effect of bolus size on the chewing cycle in humans.

No general agreement exists regarding the effect that bolus size has on masticatory movement, probably because both the size and texture of food change during mastication. In this experiment, in order to clarify the effect of bolus size on masticatory movement, a food that does not change in size and texture--chewing gum--was chosen, and the relationship between bolus size and the chewing cycle was analyzed. Ten healthy subjects in their twenties were asked to chew pieces of softened chewing gum of four different sizes. For ten cycles, beginning with the fifth cycle of mastication, gape and masticatory width were calculated for the spatial parameter of the chewing cycle, and cycle time was calculated as the temporal parameter. The relationship between these parameters and the bolus size was investigated. As the bolus size increased, the spatial and temporal parameters increased. In addition, there was a positive correlation between the bolus size and each parameter. The influence of the bolus size was as follows: gape, r = 0.91; masticatory width, r = 0.79; and cycle time, r = 0.74 (all, P < 0.001). From these results it was concluded that the shape of the chewing cycle was altered by the size of the food bolus, and that the changes in sensory input from the peripheries greatly affected the masticatory movement.

Journal Article↗
PubMed2001

Expression and localization of MGP in rat tooth cementum.

Tooth cementum, a calcified hard tissue covering the root surfaces, is an important component connecting the teeth to the collagenous fibres of the periodontal ligament. Although the overall composition of cementum may closely resemble that of bone, each part has not been fully characterized. Here, the localization of the matrix gamma-carboxyglutamic acid (Gla) protein (MGP), one of the major Gla-containing proteins in the body, in cementum was investigated using immunohistochemistry and in situ hybridization. (1) Strong MGP antigenicity was observed in the acellular cementum, but was only moderate in the cellular cementum; (2) polygonal periodontal ligament cells facing the acellular cementum and the uncalcified cellular cementum expressed MGP mRNA, indicating that these cells produced MGP and deposited it on the cementum; (3) MGP accumulated at the junction between the uncalcified and calcified cellular cementum; and (4) the distribution pattern of MGP antigenicity resembled that of osteopontin. As one function of MGP could be as a negative regulator for mineral apposition, the expression of MGP in the cells adjacent to the cementum may be important to prevent hyperapposition of minerals.

Animals↗
PubMed2001

Clinicopathological features of myeloid/natural killer (NK) cell precursor acute leukemia.

Four patients (three males and one female) were diagnosed as myeloid/natural killer (NK) cell precursor acute leukemia in our department. Two patients showed the extramedullary involvement at initial presentation. Leukemic cells expressed CD7, CD33, CD45 and CD56 in all patients. Additionally, CD13, CD34, HLA-DR, cytoplasmic CD3 and myeloperoxidase were expressed in some patients. Trisomy 10 was found in two patients, which has not been reported in this disease. Therefore, myeloid/NK cell precursor acute leukemia might be rather heterogeneous especially in chromosomal abnormality though it seemed to constitute the distinct clinical entity among acute myeloid leukemia of M0 subtype.

Acute Disease↗
PubMed2001

Granular lymphocytic leukemia derived from gamma delta T-cell expressing cytotoxic molecules.

We here present an extremely rare case of granular lymphocytic leukemia derived from gamma delta T-cell (gamma delta T-GLL). The blood picture at diagnosis was as follows; white cell count 25.7 x 10(9)/l containing 94% atypical lymphocytes with cytoplasmic granules, hemoglobin 11.8 g/dl and platelet count 124 x 10(9)/l. The atypical lymphocytes were positive for CD2, CD3, CD5, CD7, CD56 and TCR gamma delta, but negative for CD4, CD8, CD57, TCR alpha beta and B-cell antigens. The cytotoxic molecules, T-cell intracellular antigen-1 (TIA-1) and granzyme B, were positive by immunocytochemical analysis. Southern blot analysis showed rearrangement of T-cell receptor J gamma and C beta genes but germline configuration of the JH gene. Neither serum antibody against human T-cell leukemia virus type-I (HTLV-I) nor the integration of HTLV-I proviral DNA was detected. CT scan showed splenomegaly but no lymph node enlargement. A diagnosis of gamma delta T-GLL was made, and she has been followed up without any therapies for more than 4 years.

Female↗
PubMed2001

Expression of the antiapoptosis gene, AAC-11, as a prognosis marker in non-small cell lung cancer.

Inhibition of programmed cell death (apoptosis) is associated with increased tumor aggressiveness. We hypothesized that a novel apoptosis inhibitor gene, antiapoptosis clone 11 (AAC-11), may be expressed in tumors of patients with non-small cell lung cancer (NSCLC) and affect their clinical outcome. Expression of AAC-11 messenger RNA was evaluated by reverse transcription polymerase chain reaction (RT-PCR) in 94 non-small cell lung carcinomas and adjacent histologically normal lung samples. The data was analyzed in reference to clinicopathological and survival data. AAC-11 transcripts were detected in 12 (12.7%) of the tumor samples, although five of paired normal lung samples showed very weak expression. There was no relationship between AAC-11 gene expression and age, gender, N or T-status. AAC-11 was preferentially expressed in squamous cell carcinoma (26.9% of squamous cell carcinoma vs. 7% of adenocarcinoma). The NSCLC patients with AAC-11 expression had significantly poor survival than the patients without AAC-11 expression (P=0.0360). Although the AAC-11 gene was not expressed in a majority of NSCLC tumors, we suggest that AAC-11 may predict poor survival.

Adenocarcinoma↗
PubMed2001

FcgammaRIII b and FcgammaRIIa polymorphism may affect the production of specific NA1 autoantibody and clinical course of autoimmune neutropenia of infancy.

We studied 18 children with autoimmune neutropenia (AIN) to evaluate whether there was a possible relationship between the specificity of granulocyte autoantibodies (anti-NA1,2) and the phenotype of the NA system. Direct granulocyte immunofluorescence test (D-GIFT) was positive in all patients, and indirect granulocyte immunofluorescence test (I-GIFT) was positive in 17 of these 18 patients, respectively. Fourteen of 18 patients showed preferential binding to neutrophils from NA(1+2-) phenotyped donors. Immunoblotting with anti-FcgammaRIIImAb showed that IgG prepared from 7 of 12 patients precipitated both FcgammaRIIIb from NA1 and NA2 neutrophil lysate, whereas the other 5 precipitated only NA1. Patients' IgG did not react with purified FcgammaRIIa. FcgammaRIIIb genotype were NA(1+2-) in 15 of 18 patients and NA(1+2+) in the other 3. FcgammaRIIa type of all patients were (H+R-). These distributions were significantly different from those of healthy Japanese blood donors (n = 608). The genotype of FcgammaRIIIb and FcgammaRIIa may affect the production of neutrophil specific auto-antibodies in AIN of infancy and influence its clinical course.

Age of Onset↗
PubMed2001

Effect of phorbol ester and calcium ionophore on human thymocytes.

Positive selection of immature thymocytes is a developmental process in which TCR ligation with low avidity induces generation of mature T cells. In mouse thymocytes, CD4(+)8(+) double-positive (DP) cells which were treated with a proper combination of calcium ionophore ionomycin and phorbol 12-myristate 13-acetate (PMA) have been reported to differentiate into CD4 single positive cells. However, in human thymocytes the effects of PMA and ionomycin have remained unclear. Here we report that DP cells that were treated with PMA and ionomycin up-regulated bcl-2 and down-regulated CD1 expression. However, CD3 expression remained low. This treatment induced prolonged CD4 down-regulation in DP cells which was an effect also seen in mature peripheral blood T cells. PMA/ionomycin-treated DP cells showed high cell proliferation and resistance to dexamethasone-induced apoptosis. These results indicate that PKC activation and calcium elevation may be part of the biochemical signals that induce positive selection of human DP cells and the system described in this paper may be a useful model to study the signals involved in the selection of human thymocytes.

Antigens, CD1↗