Biomedical subjects

Y Kawakami

Publications and source records attributed to Y Kawakami.

At least 109 records · Page 6Linked to original sources

PubMed2001

The gene polymorphism of tumor necrosis factor-beta, but not that of tumor necrosis factor-alpha, is associated with the prognosis of sarcoidosis.

OBJECTIVES: Few genetic markers for the prognosis of sarcoidosis have been found. Tumor necrosis factor (TNF)-alpha has been implicated in the pathogenesis of sarcoidosis. Induced TNF-alpha or TNF-beta levels have been shown to be associated with the polymorphisms of the TNF genes. We investigated the roles of such polymorphisms in the development and prolongation of sarcoidosis. SUBJECTS AND MEASUREMENTS: One hundred ten Japanese patients with sarcoidosis and 161 control subjects were genotyped for three biallelic polymorphisms in the promoter region of TNF-alpha gene by direct sequencing of polymerase chain reaction (PCR) products. A polymorphism of the TNF-beta gene (TNFB*1/TNFB*2) was detected by NCO: I restriction fragment length polymorphism analysis of PCR products spanning intron 1 and exon 2 of the TNF-beta gene. RESULTS: None of the polymorphisms conferred susceptibility to sarcoidosis. However, our study identified the allele TNFB*1, detected by the presence of a NCO: I restriction site, as a marker of prolonged clinical course, with the resolution of sarcoidosis being defined as the disappearance of all clinical symptoms, physical signs of active lesions, abnormal chest radiograph findings, and abnormal results of pulmonary function and biochemical tests. When the probability of remission in patients homozygous for TNFB*2 was defined as 1.00, it was 0.48 (95% confidence interval, 0.26 to 0.88; p < 0.05) in patients with TNFB*1 (genotypes TNFB*1/1 and TNFB*1/2). CONCLUSIONS: The TNFB*1 allele is a marker for prolonged clinical course in patients with sarcoidosis. Our study is the first to link a cytokine gene polymorphism to the prognosis of sarcoidosis.

Adult↗

PubMed2001

Characterization of immortalized human chondrocytes originated from osteoarthritis cartilage.

Immortalized cloned human chondrocytes isolated from a normal (Ch-4, 8, N) and an osteoarthritis patient (Ch-8-OA) were established by introduction of recombinant SV40-adenovirus vector containing SV40 early gene. These cells exhibited continuous proliferative capacity in monolayer culture and showed chondrocytic characteristics in that they were positive for alkaline phosphatase and collagen type II. When cells were treated with IL-1alpha, the growth was inhibited. IL-1alpha induced the production of IL-6, GM-CSF and TNFalpha from immortalized chondrocytes. Significantly high amounts of cytokines including IL-6, GM-CSF and TNFalpha were produced from Ch-8-OA cells, even in the absence of IL-1alpha stimulation. Interestingly, TNFalpha, exogenously added into the culture, inhibited the growth of Ch-8-OA cells. Further studies are required to clarify the different mechanisms on chondrocytes originating from osteoarthritis cartilage underlying the biological reaction to various cytokines and the production of these cytokines as compared with chondrocytes from normal cartilages. However, the novel chondrocyte cell lines established in the present study may provide researchers with a useful model for studying the pathogenesis of osteoarthritis.

Alkaline Phosphatase↗

PubMed2001

[A case of rectal bladder construction by Duhamel procedure for vesical extrophy].

A 4 year old boy, who underwent 2 times of unsuccessful primary closure of the extrophied bladder at 7 days and 5 months after birth, was treated with construction of a rectal bladder with sigmoid-pull through by Duhamel procedure. Vas deference, seminal vesicles and prostate were not found at the cystectomy operation. Epispadias urethral mucosa was removed and phalloplasty was performed using the ventral hooded foreskin. The results were cosmetically and functionally excellent. He could keep continence and his upper urinary tract was normal at 6 months after the operation.

Bladder Exstrophy↗

PubMed2001

A significant role of stromal fibroblasts in rapidly progressive dry eye in patients with chronic GVHD.

PURPOSE: To elucidate histopathologic features of the lacrimal gland in chronic graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation. METHODS: Lacrimal gland specimens from five patients who had dry eye as part of the symptoms of chronic GVHD were examined by immunohistochemistry and transmission electron microscopy. Lacrimal gland specimens from five patients with Sjögren's syndrome (SS) were used as control samples. RESULTS: Lymphocytes, predominantly T cells, were found primarily in the periductal areas of the lacrimal gland from patients with chronic GVHD, whereas B cells were the dominant infiltrating cells in the acinar areas of the lacrimal gland from patients with SS. Notable findings in the lacrimal gland from patients with chronic GVHD were marked fibrosis of the glandular interstitium and an increase in the number of CD34(+) stromal fibroblasts. These findings were more prominent in patients with severe dry eye than in those with mild dry eye. Electron microscopic observations of the lacrimal gland from patients with chronic GVHD revealed that stromal fibroblasts were attached to various inflammatory cells, especially T cells, through primitive or rudimentary contacts. In addition, the presence of a well-developed rough endoplasmic reticulum in the fibroblasts and newly synthesized collagen fibrils in the extracellular matrix indicated an active production of extracellular matrix components. Electron micrographs revealed multilayered and thickened basal laminae of blood vessels, ducts, and lobules in the lacrimal gland of patients with chronic GVHD; however, these observations were infrequently observed in the lacrimal glands of patients with SS. CONCLUSIONS: The results suggest substantial differences in the lacrimal gland histopathology of patients with chronic GVHD and SS. In addition, it is likely that stromal fibroblasts are actively involved in the pathogenic process of chronic GVHD in the lacrimal gland by producing excessive extracellular matrix components.

Adult↗

PubMed2001

Mechanical vibratory stimulation of feline forepaw skin induces long-lasting potentiation in the secondary somatosensory cortex.

We investigated the long-lasting effects of mechanical vibratory stimulation of the skin on the excitability of feline cortical neurons in the forelimb areas of the primary (SI) and secondary (SII) somatosensory cortices. Conditioning mechanical stimuli were 300 bursts of 10 pulses at 200 Hz delivered with a 10-s interburst interval from a mechanical stimulator. Test field potentials and unit discharges were evoked by electrical stimulation to the ventral posterolateral thalamic nucleus (VPL) or by single mechanical stimuli applied to the skin. In SII, the mechanical burst stimulation to the skin increased the amplitudes of field potentials and the frequency of unit discharges elicited by single mechanical stimuli applied to the skin. The vibratory conditioning stimulus also produced a similar potentiation of the VPL-evoked field potentials (126-139% increase in amplitude, P < 0.05) with an associated increase in firing rates of extracellularly recorded neuronal activity (117%, P < 0.001). These potentiations persisted through the entire experimental period of 120 min. The translaminar current source density analysis calculated from the VPL-evoked field potentials increased to 127% of the control value (P < 0.01). In contrast, in SI we observed no significant changes in the field potential amplitudes or in the currents generated in superficial layers (91-117%). Taken together with the previous finding that tetanic electrical stimulation of VPL induces long-lasting potentiation of the VPL-evoked cortical responses in SII but not of those in SI, the present results suggest that SII has a large capacity for the rapid functional plasticity involved in the learning that occurs during repeated tactile experiences.

Animals↗

PubMed2001

Molecular and epidemiological study of the first outbreak of vanB type vancomycin-resistant Enterococcus faecalis in Japan.

In July, 1999, an outbreak of vancomycin-resistant Enterococcus faecalis (VREF) with the vanB genotype occurred for the first time in Japan at Hokushin General Hospital, Nakano City, Nagano Prefecture. Four VREF strains were isolated from the clinical specimens of four inpatients, and 16 VREF strains were isolated by the screening of asymptomatic carriers and by surveillance of the hospital environment. All of the isolates possessed vanB genes. In a pulsed-field gel electrophoresis analysis, 19 out of 20 VREF isolates exhibited the indistinguishable restriction endonuclease digestion patterns of the chromosomal DNA. Additional investigation by Southern hybridization using the vanB probe implied that the vanB gene of these 19 isolates was encoded on a 110-kb plasmid. These findings indicate that the outbreak was principally caused by a single clone. The restriction endonuclease digestion patterns of the remaining single isolate was different from those of the other isolates. The vanB gene was encoded on the chromosome.

Aged↗

PubMed2001

Five cases of the lymphangioma of the mediastinum in adult.

Mediastinal lymphangioma is rare disease. Above all cavernous type of mediastinal lymphangioma is very rare. We report 5 cases of mediastinal lymphangioma including cavernous type. CT was performed in all and revealed that they were smoothly marginated and cystic. All were surgically resected and specimens were classified pathologically into cystic type (3 cases), cavernous type (1 case) and mixed type of the two (1 case). MRI was performed in the cavernous type and suggested that the mass was lymphangioma because of pathognomonic lesion. Despite preoperative diagnosis of mediastinal lymphangioma is difficult, MRI is able to useful examination. In the follow-ups there has been no recurrence in our series.

Adult↗

PubMed2001

[Weekly paclitaxel and cisplatin in recurrent ovarian cancer].

This study was performed to assess the feasibility of weekly paclitaxel (TXL) and cisplatin (CDDP) in patients with recurrent ovarian cancer. Ten of eleven patients experienced recurrence after more than 6 months after first line CDDP-based chemotherapy. TXL and CDDP were given at initial doses of 60 mg/m2 and 30 mg/m2 on days 1, 8, and 15 in 2 patients and an increase in the respective dose level was planned to 60/35 in 5 patients, 70/35 in 2 patients, and 70/40 in 2 patients. Toxicities were well tolerated. None of the patients suffered from neurotoxicity or myalgia of more than grade 2. Gastrointestinal disorder was recognized as grade 1-2, and grade 3-4 hematological toxicity included leucocytopenia (64%), anemia (36%), and thrombocytopenia (9%). We set the recommended dose of TXL at 70 mg/m2 and that of CDDP at 35 mg/m2, considering toxicity and performed planned schedule. Of eleven patients, nine were assessable by computed tomographic scan. The overall response rate was 67% (CR: 1, PR: 5, NC: 1, PD: 2). One of two patients with standard TXL/CDDP therapy showed PR by switching to a weekly schedule. The median follow-up duration was 490 days and the median response duration was 371 days. From the results presented here, it is suggested that this regimen with increased DI might be quite effective and well tolerated in patients who experience relapse after CDDP-based chemotherapy.

Adult↗

PubMed2001

[Noninvasive methods to monitor the production of hormone].

Noninvasive method to screen for endogeneous hormone production is useful to diagnose hormone excess/deficiency, especially in children. There are currently some optimal test to diagnose, and these tests(for example, urinary GH, urinary cortisol, urinary cathecolamine...) has been widely used. Traditional 24-hour urine or midnight serum cortisol values may be difficult to obtain or elevated by venipuncture stress. Salivary cortisol measurement has been reported as a reliable way to screen for adrenocortical function. We tried to detect salivary cortisol level with drug loading test(Dexamethasone for Cushing syndrome, and ACTH for adrenal insufficiency) with time interval. Salivary cortisol measurement with drug loading test rules out both Cushing syndrome and adrenal insufficiency in nearly all cases. Salivary cortisol sampling is thus a simple, accurate way to screen for adrenocortical function.

Child↗

PubMed2001

Evaluation of insulin secretion of isolated rat islets cultured in extracellular matrix.

Islet isolation involves enzymatic digestion of the interstitial matrix and mechanical disruption of the tissue. It is possible that a fundamental change of islet biology resulting from the loss of critical factors required for islet function or survival will occur. Extracellular matrix (ECM) is one of the most important components of the islet microenvironment. Reconstruction of the cell-matrix relationship seems to be effective for improving the loss of differentiated islet structure and function. The purpose of this study was to characterize and compare the effects of collagen gel mixture or Matrigel on beta-cell function and islet cell survival. After isolation by the collagenase digestion technique, rat islets were divided and cultured with various types of collagen gel mixture. They were assessed for their glucose-stimulated insulin secretion and cell viability. Glucose-induced insulin secretion of islets cultured with collagen type I gel or a mixture of collagen type I and IV was improved after 11 days in culture. In conclusion, a type of gel composed of collagen type I and/or type IV as an islet microenvironment is sufficient to maintain glucose responsiveness and may be useful for islet transplantation.

Animals↗

PubMed2001

Development of a new method to induce angiogenesis at subcutaneous site of streptozotocin-induced diabetic rats for islet transplantation.

The subcutaneous space is a potential site for clinical islet transplantation. Even though there are several advantages, poor blood supply at this site mainly causes failure of islet survival. In this study, angiogenesis was induced in advance at the diabetic rats subcutis for islet transplantation by implanting a polyethylene terephthalate (PET) mesh bag containing gelatin microspheres incorporating basic fibroblast growth factor (bFGF) (MS/bFGF) and a collagen sponge. The bFGF was incorporated into gelatin microspheres for controlled release of bFGF. As controls, a PET mesh bag with or without either collagen sponges or MS/bFGF was implanted at the subcutaneous site of diabetic rats. Macroscopic and microscopic examinations revealed the formation of capillary network in and around the PET mesh bag containing MS/bFGF and collagen sponges 7 days after implantation when compare with other control groups. When tissue hemoglobin level was also measured, a significantly high level of hemoglobin amount was observed compared with that of control groups. When allogeneic islets mixed with 5% agarose were transplanted into the prevascularized rat subcutis, normoglycemia was maintained for more than 40 days, while other control groups were ineffective. This study demonstrated that combination of gelatin microspheres incorporating bFGF and collagen sponges enabled the mesh to induce neovascularization even at the subcutaneous site of streptozotocin-induced diabetic rats, resulting in improved function of islet transplantation.

Animals↗

PubMed2001

Hepatitis B virus concentrations in serum determined by sensitive quantitative assays in patients with established chronic hepatitis delta virus infection.

To clarify the correlation between hepatitis B virus (HBV) DNA levels and serum alanine aminotransferase (ALT) levels in patients with established chronic hepatitis delta virus (HDV) infection, sensitive HBV quantitative assays were used for the study. Thirty-four consecutive patients with chronic liver disease who were positive for both hepatitis B surface antigen (HBsAg) and antibody to HDV (anti-HDV), including 19 patients with chronic hepatitis, 8 patients with liver cirrhosis and 7 patients with hepatocellular carcinoma. All were negative for hepatitis Be antigen (HBeAg) and positive for antibody to HBeAg. HBV DNA was detected in 25 (73.5%) of the 34 patients using real-time detection PCR, and the HBV DNA levels of these patients were significantly lower compared with HBeAg status and ALT level-matched patients with chronic liver disease positive for HBsAg but negative for anti-HDV. There was no correlation between serum HBV DNA and ALT levels among the 34 patients with chronic liver disease positive for anti-HDV. Whereas serum ALT levels in anti-HDV-positive HBsAg carriers with HDV RNA were significantly higher than those without HDV RNA. Liver damage in patients with established chronic HDV infection may be caused mainly by ongoing HDV infection not by HBV replication.

Adult↗

PubMed2001

[Recent topics on basic research for idiopathic thrombocytopenic purpura].

Idiopathic thrombocytopenic purpura (ITP) is an autoimmune disease characterized by increased platelet clearance caused by anti-platelet autoantibodies, which bind to circulating platelets resulting in destruction. by the reticuloendothelial system. We have recently developed enzyme-linked immunospot assay to detect circulating B cells secreting anti-platelet antibody. An increase in anti-platelet antibody-producing B cells in peripheral blood was specifically detected in ITP patients, but in none of thrombocytopenic patients without ITP or healthy donors. While earlier studies reported the presence of platelet-reactive T cells in ITP patients, we have recently found that GPIIb-IIIa is one of major target antigens recognized by platelet-reactive CD4+ T cells. Since GPIIb-IIIa-reactive CD4+ T cells had helper activity promoting production of anti-platelet antibody, these autoreactive T cells are involved in production of pathogenic anti-platelet autoantibody in ITP patients. Suppression of GPIIb-IIIa-reactive CD4+ T cells may be of therapeutic use in treating refractory patients.

Antibody-Producing Cells↗

PubMed2000

Akt-dependent cytokine production in mast cells.

Cross-linking of FcepsilonRI induces the activation of three protein tyrosine kinases, Lyn, Syk, and Bruton's tyrosine kinase (Btk), leading to the secretion of a panel of proinflammatory mediators from mast cells. This study showed phosphorylation at Ser-473 and enzymatic activation of Akt/protein kinase B, the crucial survival kinase, upon FcepsilonRI stimulation in mouse mast cells. Phosphorylation of Akt is regulated positively by Btk and Syk and negatively by Lyn. Akt in turn can regulate positively the transcriptional activity of interleukin (IL)-2 and tumor necrosis factor (TNF)-alpha promoters. Transcription from the nuclear factor kappaB (NF-kappaB), nuclear factor of activated T cells (NF-AT), and activator protein 1 (AP-1) sites within these promoters is under the control of Akt activity. Accordingly, the signaling pathway involving IkappaB-alpha, a cytoplasmic protein that binds NF-kappaB and inhibits its nuclear translocation, appears to be regulated by Akt in mast cells. Catalytic activity of glycogen synthase kinase (GSK)-3beta, a serine/threonine kinase that phosphorylates NF-AT and promotes its nuclear export, seems to be inhibited by Akt. Importantly, Akt regulates the production and secretion of IL-2 and TNF-alpha in FcepsilonRI-stimulated mast cells. Altogether, these results revealed a novel function of Akt in transcriptional activation of cytokine genes via NF-kappaB, NF-AT, and AP-1 that contributes to the production of cytokines.

Animals↗

PubMed2000

Immuno-histochemical detection of human telomerase reverse transcriptase in human liver tissues.

Although telomerase activity in hepatocellular carcinoma (HCC) increases in accordance with degree of histological undifferentiation, it is unknown whether the level of telomerase activity in HCC reflects of the degree of activity in individual cells or the frequency of telomerase-positive HCC cells. Non-cancerous liver tissues exhibit low but significant levels of telomerase activity, but the nature of telomerase-positive cells in these tissues is unclear. In this study, we performed immunohistochemical staining using specific antibody against telomerase reverse transcriptase (hTERT) protein in 15 HCC samples and 13 adjacent non-cancerous liver tissues. There were hTERT-positive hepatocytes, though very low frequency, in non-cancerous liver tissues. The frequencies in hTERT positive hepatocytes were very well correlated with clinicopathological parameters and telomerase activity levels: the average frequencies of chronic hepatitis was 0.2%, liver cirrhosis 0.2%, well-differentiated HCC 3.0%, moderately differentiated HCC 28%, and poorly differentiated HCC 95%. The intensity of staining varied among cells within a given specimen, and correlation with degree of histological undifferentiation was less obvious. Portions of migrating lymphocytes and biliary epithelial cells were also hTERT-positive. These findings indicate that the upregulation of telomerase activity with degree of undifferentiation of HCC is mainly due to the increase in frequency of hTERT positive HCC cells.

Carcinoma, Hepatocellular↗

PubMed2000

Orexins suppress catecholamine synthesis and secretion in cultured PC12 cells.

New orexigenic peptides called orexin-A and -B have recently been described in neurons of the lateral hypothalamus and perifornical area. No orexins have been found in adipose tissues or visceral organs, including the adrenal gland. However, expression of the orexin-receptor 2 (OX2R) in the rat adrenal gland has been reported. To test the effects of orexins on peripheral organs, we investigated their effects on catecholamine synthesis and secretion in the rat pheochromocytoma cell line PC12. Orexin-A and -B (100 nM) significantly reduced basal and PACAP-induced tyrosine hydroxylase (TH) (the rate-limiting enzyme in the biosynthesis of catecholamines) mRNA levels. Orexin-A and -B (100 nM) also significantly inhibited the PACAP-induced increase in the cAMP level, suggesting that the suppressive effect on TH mRNA is mediated, at least in part, by the cAMP/protein kinase A pathway. Furthermore, orexin-A and -B (100 nM) significantly suppressed basal and PACAP-induced dopamine secretion from PC12 cells. Next, we examined whether orexin receptors (OX1R, OX2R) were present in the rat adrenal gland and PC12 cells. In the adrenal glands, OX2R was as strongly expressed as in the hypothalamus, but OX1R was not detected. On the other hand, neither OX1R nor OX2R was expressed in PC12 cells. However, binding assays showed equal binding of orexin-A and -B to PC12 cells, suggesting the existence in these cells of some receptors for orexins. These results indicate that orexins suppress catecholamine release and synthesis, and that the inhibitory effect is mediated by the cAMP/protein kinase A pathway.

Adrenal Gland Neoplasms↗

PubMed2000

Redundant and opposing functions of two tyrosine kinases, Btk and Lyn, in mast cell activation.

Protein-tyrosine kinases play crucial roles in mast cell activation through the high-affinity IgE receptor (FcepsilonRI). In this study, we have made the following observations on growth properties and FcepsilonRI-mediated signal transduction of primary cultured mast cells from Btk-, Lyn-, and Btk/Lyn-deficient mice. First, Lyn deficiency partially reversed the survival effect of Btk deficiency. Second, FcepsilonRI-induced degranulation and leukotriene release were almost abrogated in Btk/Lyn doubly deficient mast cells while singly deficient cells exhibited normal responses. Tyrosine phosphorylation of cellular proteins including phospholipases C-gamma1 and C-gamma2 was reduced in Btk/Lyn-deficient mast cells. Accordingly, FcepsilonRI-induced elevation of intracellular Ca2+ concentrations and activation of protein kinase Cs were blunted in the doubly deficient cells. Third, in contrast, Btk and Lyn demonstrated opposing roles in cytokine secretion and mitogen-activated protein kinase activation. Lyn-deficient cells exhibited enhanced secretion of TNF-alpha and IL-2 apparently through the prolonged activation of extracellular signal-related kinases and c-Jun N-terminal kinase. Potentially accounting for this phenomenon and robust degranulation in Lyn-deficient cells, the activities of protein kinase Calpha and protein kinase CbetaII, low at basal levels, were enhanced in these cells. Fourth, cytokine secretion was severely reduced and c-Jun N-terminal kinase activation was completely abrogated in Btk/Lyn-deficient mast cells. The data together demonstrate that Btk and Lyn are involved in mast cell signaling pathways in distinctly different ways, emphasizing that multiple signal outcomes must be evaluated to fully understand the functional interactions of individual signaling components.

Agammaglobulinaemia Tyrosine Kinase↗

PubMed2000

Immunostained cathepsins B and L correlate with depth of invasion and different metastatic pathways in early stage gastric carcinoma.

BACKGROUND: With the recent development of minimal treatment for early stage gastric carcinoma, identifying specific indicators of the metastatic potential of primary tumors has become more important. Cathepsin B and cathepsin L, both lysosomal cysteine proteases, degrade the extracellular matrix during tumor progression. Although many studies have shown their relation to human cancer progression, little is known about their roles in the early stage. The clinicopathologic significance of cathepsins was therefore studied in early stage gastric carcinoma. METHODS: Expression of both cathepsins was studied immunohistochemically in 51 tissue specimens from gastric carcinomas that invaded the submucosal layer or muscularis propria. The relation between their expression and clinicopathologic factors was analyzed. RESULTS: Both cathepsins were expressed at higher levels in tumors that invaded the muscularis propria than in those within the submucosa (P < 0.05). In addition, tumors with lymphatic invasion showed higher cathepsin B expression than those without it (P < 0.05), whereas tumors with venous invasion showed higher cathepsin L expression than those without it (P < 0.05). No other clinicopathologic factors correlated with expression of either cathepsin. CONCLUSIONS: Tumors with overexpression of cathepsins have powerful potential for invasiveness in the early stage of gastric carcinoma. Moreover, the authors hypothesize that cathepsins may be one of the determinants of the metastatic route. To the authors' knowledge, this is the first report on specific proteases concerning the mode of metastasis, and the results of this study suggest that therapeutic strategies for early stage gastric carcinoma might need to be changed according to the status of cathepsins.

Adult↗