Search PubMed⌕ Search

Biomedical subjects

H Sakai

Publications and source records attributed to H Sakai.

At least 271 records · Page 15Linked to original sources
PubMed1999

Para-articular chondroma and osteochondroma of the infrapatellar fat pad: a report of three cases.

We report three cases of para-articular chondroma and osteochondroma in the region of infrapatellar fat pad. All three lesions were resected and examined histologically. Two of them were primarily cartilaginous with a lobular pattern internally, and one uniformly osseous with peripheral cartilage. We conclude that these lesions are not the same. The former should be designated para-articular chondroma after Jaffe and the latter, osteochondroma.

Adipose Tissue↗
PubMed1999

Glucocorticoids inhibit proliferation and adhesion of the IL-3-dependent mast cell line, MC/9, to NIH/3T3 fibroblasts, with an accompanying decrease in IL-3 receptor expression.

We investigated the effects of glucocorticoids on IL-3-dependent proliferation and c-kit expression of cells of the mouse mast cell line, MC/9. Glucocorticoids (dexamethasone, prednisolone, and hydrocortisone) inhibited IL-3-dependent MC/9 cell proliferation, whereas sex steroids (progesterone, beta-estradiol, and testosterone) had no effect. Flow cytometric analysis revealed that glucocorticoids reduced the expression of the IL-3 receptor on MC/9 cells. Immunoblot and Northern blot analyses indicated that glucocorticoids also reduced the expression of both c-kit protein and c-kit mRNA transcript. Furthermore, the adhesion of MC/9 cells to stem cell factor-expressing NIH/3T3 cells was reduced following glucocorticoid treatment. Our results indicate that glucocorticoids inhibit IL-3-dependent MC/9 mast cell proliferation, with an accompanying decrease in IL-3 receptor expression. Glucocorticoids also reduced c-kit expression on MC/9 cells resulting in a decreased adhesion to NIH/3T3 fibroblasts.

3T3 Cells↗
PubMed1999

FK506 and cyclosporin A inhibit stem cell factor-dependent cell proliferation/survival, while inducing upregulation of c-kit expression in cells of the mast cell line MC/9.

Murine mast cell proliferation and maturation are regulated by two distinct cytokines, interleukin-3 (IL-3) and the c-kit ligand, stem cell factor (SCF). In this study using cells of the mouse mast cell line, MC/9, the effects of two immunosuppressants, FK506 and cyclosporin A (CsA), were investigated. Withdrawal of IL-3 from the culture medium resulted in loss of viability of MC/9 cells. The addition of SCF in the absence of IL-3 maintained MC/9 cell survival but no cell proliferation was detected. The combined addition of IL-3 and SCF to the culture medium resulted in a more marked MC/9 cell proliferation than the addition of IL-3 alone. FK506 and CsA inhibited the SCF-dependent, but not the IL-3 dependent, stimulatory effects on MC/9 cell proliferation/survival. Apoptotic changes were analyzed using fluorescent staining with acridine orange and DNA electrophoresis. FK506 and CsA inhibited the SCF-dependent rescue effect from apoptosis. Flow cytometry showed that FK506 and CsA did not affect IL-3 receptor expression. However, immunoblot and reverse transcriptase-polymerase chain reaction (RT-PCR) analyses indicated that c-kit protein and c-kit mRNA transcripts were increased following the FK506 and CsA treatments in the presence of IL-3. In addition, MC/9 cells pretreated with FK506 or CsA showed an increased adhesiveness to NIH/3T3 cells that express membrane-bound SCF. Neither FK506 nor CsA affected c-kit tyrosine phosphorylation or MAP kinase nuclear translocation of MC/9 cells following SCF stimulation. These results indicate that FK506 and CsA, while inducing c-kit of MC/9 cells, selectively inhibit the SCF-dependent stimulatory effects on MC/9 cell proliferation/survival by a mechanism independent of, or at point(s) distal to, the c-kit-MAP kinase pathway.

3T3 Cells↗
PubMed1999

Quantitative analysis of alpha 1(I) and alpha 1(III) procollagen mRNA expression in systemic sclerosis skin tissue--an in situ hybridization study.

Human alpha 1(I) and alpha 1(III) procollagen mRNA expression in skin tissue from 15 systemic sclerosis (SSc) patients and from 7 normal control subjects was quantitatively analyzed using in situ hybridization. The grains accumulating in each area, representing procollagen mRNA expression per cell, were counted. To normalize the results from each subject, the number of cells and the number of grains per cell were divided by the area of the skin specimen (in square millimeters). The number of cells per square millimeter expressing alpha 1(I) and alpha 1(III) procollagen mRNA in SSc skin was significantly elevated compared with normal control skin (both P < 0.01). The number of grains per cell per square millimeter expressing alpha 1(III) procollagen mRNA in SSc skin was also significantly elevated compared with normal control skin (P < 0.01). The relationship between procollagen mRNA expression and the histological findings in SSc was also studied. The numbers of cells and grains per cell per square millimeter expressing alpha 1(I) procollagen mRNA in fibrotic zone SSc skin were significantly elevated compared with normal control skin (both P < 0.01). The numbers of cells and grains per cell per square millimeter expressing alpha 1(III) procollagen mRNA in SSc skin were significantly elevated compared with normal control skin (both P < 0.01) and with border zone SSc skin (number of cells P < 0.01, number of grains P < 0.05). These results indicate an increase in the number of cells showing elevated expression of alpha 1(I) and alpha 1(III) procollagen mRNA, and a close relationship between alpha 1(I) and alpha 1(III) procollagen mRNA expression and the histological findings in SSc.

Adult↗
PubMed1999

Induction of apoptosis in rat hepatic stellate cells by disruption of integrin-mediated cell adhesion.

Cell-matrix adhesion is recognized as a physiologic determinant of cell growth and survival. Integrin occupancy seems to be a primary role. We sought to investigate the signal transduction pathways for integrin effects on cell survival in hepatic stellate cells. Integrin function was antagonized by the soluble integrin recognition sequence pentapeptide Gly-Arg-Gly-Asp-Ser (GRGDS) in primary cultures of rat hepatic stellate cells. Integrin antagonism with GRGDS peptide induced apoptosis. To investigate signal transduction mechanisms for the effect of integrins on cell survival in hepatic stellate cells, the expression of p53, Bcl-2, and Bax was analyzed. Incubation with soluble GRGDS peptide resulted in increased expression of p53 and decreased the Bcl-2/Bax ratio. In conclusion, these findings indicate that the abrogation of cell adhesion with soluble GRGDS peptide plays a critical role in the induction of apoptosis of rat hepatic stellate cells.

Animals↗
PubMed1999

Expression of E-cadherin in bone and soft tissue sarcomas: a possible role in epithelial differentiation.

The cadherin-mediated cell-cell adhesion system is now known to play a critical role in both the morphogenesis of cancer cells and suppression of their invasion. However, the pattern of expression of E-cadherin, the major cadherin of epithelial cells in bone and soft tissue sarcomas, remains unclear. This prompted us to study E-cadherin expression in a variety of bone and soft tissue sarcomas. Using the monoclonal antibody HECD-1, raised against the extracellular domain of E-cadherin, we observed immunoreactivity in 1 pleomorphic rhabdomyosarcoma, 2 of 5 diffuse mesotheliomas, 4 of 5 clear cell sarcomas, 1 of 5 epithelioid sarcomas, and 10 synovial sarcomas. Other types of bone and soft tissue sarcoma (4 osteosarcomas, 4 chondrosarcomas, 3 primitive neuroectodermal tumors, 1 fibrosarcoma, 4 malignant fibrous histiocytomas, 5 liposarcomas, 4 leiomyosarcomas, 6 alveolar and 5 embryonal rhabdomyosarcomas, 4 angiosarcomas, 4 malignant peripheral nerve sheath tumors, 2 extraskeletal myxoid chondrosarcomas, 2 extraskeletal osteosarcomas, and 3 alveolar soft part sarcomas) were completely negative for E-cadherin. Our findings indicate that E-cadherin is expressed in certain kinds of soft tissue sarcomas, especially those with epithelioid features, suggesting that E-cadherin plays a role in the constitution of their architecture.

Bone Neoplasms↗
PubMed1999

ALL- and CML-type BCR/ABL mRNA transcripts in chronic myelogenous leukemia and related disorders.

Using the reverse transcription polymerase chain reaction, we investigated acute lymphoid leukemia (ALL)-type, and chronic myelogenous leukemia (CML)-type BCR/ABL mRNA expression in a total of 66 patients with chronic myeloproliferative disorder (CMPD). Thirty-six of 37 patients with CML were positive for CML-type mRNA. Thirteen of the 25 CML had ALL-type mRNA expression. The patients with ET, PV, MF, and CMML did not have any detectable BCR/ABL expression. The most remarkable finding was that two patients, a Ph1-positive CML patient and a patient with a presumptive diagnosis of essential thrombocythemia (ET), showed only ALL-type chimeric mRNA expression.

Adult↗
PubMed1999

Role of Rho small GTP binding protein in the regulation of actin cytoskeleton in hepatic stellate cells.

BACKGROUND/AIMS: In the fibrotic response to liver injury, hepatic stellate cells are activated, leading to the myofibroblastic cell shape, with actin cytoskeletal reorganization and increased extracellular matrix production. The reorganization of actin cytoskeleton suggests that the small GTP binding protein Rho might modulate the process of this myofibroblastic change. The aim of this study was to investigate the role of Rho in the phenotypic changes of hepatic stellate cells. METHODS: The phenotypic changes were investigated by the overexpression of Rho regulator, Rho GDI or dominant negative mutant of Rho in mouse hepatic stellate cell line, GRX cells. In activated rat hepatic stellate cells, the effects of microinjection of Botulinus toxin C3, which is the specific inhibitor for Rho, were analyzed. Furthermore, the effect of C3 on the type I collagen accumulation in hepatic stellate cells was investigated. RESULTS: Overexpression of Rho GDI or the dominant negative mutant of Rho caused the shrinkage cell shape and suppressed stress fiber formation. Microinjection of toxin C3 caused a markedly distorted cell shape and the disappearance of stress fibers in rat stellate cells. In addition, C3 strongly suppressed collagen accumulation in activated stellate cells. CONCLUSIONS: These results suggest that Rho regulates the actin cytoskeletal reorganization, and may be implicated in the collagen accumulation in activated stellate cells. These findings provide evidence for the role of Rho in the myofibroblastic phenotype in hepatic stellate cells.

Actins↗
PubMed1999

Prognosis of parathyroid function after successful percutaneous ethanol injection therapy guided by color Doppler flow mapping in chronic dialysis patients.

Selective percutaneous ethanol injection therapy (PEIT) of the parathyroid glands has been shown to be effective in chronic dialysis patients with severe secondary hyperparathyroidism. In this study, we examined whether it was possible to maintain parathyroid function within target range (intact parathyroid hormone [iPTH], 160 to 360 pg/mL) in the long term after successful destruction of hyperplastic tissue. PEIT was performed in 46 patients resistant to calcitriol pulse therapy, and all glands larger than 5 mm in diameter were destroyed by ethanol, guided by power Doppler flow mapping. Serum iPTH levels decreased from 633.3 +/- 359.9 to 226.3 +/- 204.7 pg/mL at 3 weeks and were maintained at 289.9 +/- 222.4 pg/mL at 1 year after PEIT. Total alkaline phosphatase activity decreased from 384.9 +/- 160.1 to 234.0 +/- 110.5 IU/L at 1 year after PEIT. In 19 patients, iPTH levels decreased into relative hypoparathyroidism (iPTH < 160 pg/mL) at 3 weeks after PEIT; however, they recovered at 1 year after PEIT (191.1 +/- 29.6 pg/mL). Parathyroid function was maintained within target range in 80.4% of the patients at 1 year after PEIT with appropriate medical therapy. Surgical parathyroidectomy was not required in any patient. Conversely, in eight other patients with recurrent hyperparathyroidism after subtotal parathyroidectomy, iPTH levels recovered in only 50% of the patients at 1 year after PEIT. Thus, destruction of hyperplastic tissue should be optimized in such patients. Recurrent nerve palsy was observed in only one patient, but was reversible. In conclusion, selective PEIT guided by color Doppler flow mapping is an effective and safe adjunct to medical therapy with a low risk for hypoparathyroidism.

Administration, Cutaneous↗
PubMed1999

The distribution of BrdU- and TUNEL-positive cells during odontogenesis in mouse lower first molars.

This study investigated the minute distribution of both proliferating and non-proliferating cells, and cell death in the developing mouse lower first molars using 5-bromo-2'-deoxyuridine (BrdU) incorporation and the terminal deoxynucleotidyl transferase-mediated deoxyuridine-5'-triphosphate (dUTP)-biotin nick end labeling (TUNEL) double-staining technique. The distribution pattern of the TUNEL-positive cells was more notable than that of the BrdU-positive cells. TUNEL-positive cells were localized in the following six sites: (1) in the most superficial layer of the dental epithelium during the initiation stage, (2) in the dental lamina throughout the period during which tooth germs grow after bud formation, (3) in the dental epithelium in the most anterior part of the antero-posterior axis of the tooth germ after bud formation, (4) in the primary enamel knot from the late bud stage to the late cap stage, (5) in the secondary enamel knots from the late cap stage to the late bell stage, and (6) in the stellate reticulum around the tips of the prospective cusps after the early bell stage. These peculiar distributions of TUNEL-positive cells seemed to have some effect on either the determination of the exact position of the tooth germ in the mandible or on the complicated morphogenesis of the cusps. The distribution of BrdU-negative cells was closely associated with TUNEL-positive cells, which thus suggested cell arrest and the cell death to be essential for the tooth morphogenesis.

Animals↗
PubMed1999

Soluble Arg-Gly-Asp peptides reduce collagen accumulation in cultured rat hepatic stellate cells.

Hepatic stellate cells play a central role in the pathogenesis of liver fibrosis, both via production of extracellular matrix proteins and through secretion of matrix metalloproteinases. In this study, effects of soluble cell adhesion peptides on collagen type I accumulation and on expression of matrix metalloproteinases were analyzed. First, we revealed the expression of alpha5-integrin on hepatic stellate cells by immunostaining. Treatment with 100 microg/ml of soluble Arg-Gly-Asp (RGD) peptides was found to reduce accumulation of type I collagen without any effects on its transcriptional level in rat hepatic stellate cells, whereas a control peptide Gly-Arg-Gly-Glu-Ser (GRGES) had no such effect. Soluble RGD peptides also increased the secretion of collagenase by stellate cells. These data suggested that reduced accumulation of type I collagen caused by the RGD peptide ligation to integrins on hepatic stellate cells was partly due to stimulated expression of collagenase by stellate cells.

Animals↗
PubMed1999

Vascular endothelial growth factor-C expression in human prostatic carcinoma and its relationship to lymph node metastasis.

Lymph node dissemination is a major prognostic factor in human cancer. However, the molecular mechanisms underlying lymph node metastasis are poorly understood. Recently, vascular endothelial growth factor-C (VEGF-C) was identified as a ligand for VEGF receptor-3 (VEGFR-3/Flt-4) and the expression of VEGFR-3 was found to be highly restricted to the lymphatic endothelial cells. In this report, we investigated the expression of VEGF-C and VEGFR-3 in human prostatic carcinoma tissue by using in situ hybridization and immunohistochemical staining respectively. Expression of VEGF-C mRNA in prostatic carcinoma was significantly higher in lymph node-positive group than in lymph node-negative group. In addition, the number of VEGFR-3-positive vessels was increased in stroma surrounding VEGF-C-positive prostatic carcinoma cells. These results suggest that the expression of VEGF-C in prostatic carcinoma cells is implicated in the lymph node metastasis.

Adenocarcinoma↗
PubMed1999

Role of N-glycosylation in cathepsin E. A comparative study of cathepsin E with distinct N-linked oligosaccharides and its nonglycosylated mutant.

Cathepsin E (CE), a nonlysosomal, intracellular aspartic proteinase, exists in several molecular forms that are N-glycosylated with high-mannose and/or complex-type oligosaccharides. To investigate the role of N-glycosylation on the catalytic properties and molecular stability of CE, both natural and recombinant enzymes with distinct oligosaccharides were purified from different sources. An N-glycosylation minus mutant, that was constructed by site-directed mutagenesis (by changing asparagine residues to glutamine and aspartic acid residues at positions 73 and 305 in potential N-glycosylation sites of rat CE) and expressed in normal rat kidney cells, was also purified to homogeneity from the cell extracts. The kinetic parameters of the nonglycosylated mutant were found to be essentially equivalent to those of natural enzymes N-glycosylated with either high-mannose or complex-type oligosaccharides. In contrast, the nonglycosylated mutant showed lower pH and thermal stabilities than the glycosylated enzymes. The nonglycosylated mutant exhibited particular sensitivity to conversion to a monomeric form by 2-mercaptoethanol, as compared with those of the glycosylated enzymes. Further, the high-mannose-type enzymes were more sensitive to this agent than the complex-type proteins. A striking difference was found between the high-mannose and complex-type enzymes in terms of activation by ATP at a weakly acidic pH. At pH 5.5, the complex-type enzymes were stabilized by ATP to be restored to the virtual activity, whereas the high-mannose-type enzymes as well as the nonglycosylated mutant were not affected by ATP. These results suggest that N-glycosylation in CE is important for the maintenance of its proper folding upon changes in temperature, pH and redox state, and that the complex-type oligosaccharides contribute to the completion of the tertiary structure to maintain its active conformation in the weakly acidic pH environments.

Adenosine Triphosphate↗
PubMed1999

A diary form quality of life questionnaire for Japanese patients with lung cancer and summarization techniques for longitudinal assessment.

The aim of this study was to confirm the validity and reliability of a new diary-type quality of life (QOL) self-rating questionnaire tailored for use by Japanese inpatients with lung cancer receiving chemotherapy. Two kinds of summary statistics were tested in QOL analysis. The questionnaire has a four-scale structure; physical, psychological, daily activity and global scales. Fifty-three patients were enrolled to test the reliability and validity. Summary statistics were assessed using indices of the area under the curve (AUC) and the maximum fluctuations of QOL scores (Dif max) in patients receiving cisplatin or carboplatin. The questionnaire had satisfactory reliability and validity. The physical, psychological and global scales scores changed to the worst levels after treatment, continuing for 1 week in the cisplatin group, whereas those of the carboplatin group began to worsen from day 3, but returned to prechemotherapy levels by day 9. The cisplatin group showed significant decrease of QOL compared with the carboplatin group in the AUC of psychological and two global scales, in the Dif max of psychological and linear analogue global scales. These results suggested that this questionnaire reflects differences in the influence of chemotherapy, and that AUC and Dif max may be useful indices for the analysis of QOL as measures to assess multidimensional QOL.

Adult↗
PubMed1999

Serum and urinary concentrations of heparan sulfate in patients with diabetic nephropathy.

BACKGROUND: Heparan sulfate (HS) contributes to the negative charge in the glomerular basement membrane (GBM), which may maintain the GBM charge barrier. Changes in sulfation and/or the concentration of HS may be associated with the development of diabetic nephropathy. METHODS: Using two different antibodies specific for HS chains, one that reacts with the N-sulfated sequences in HS chains (10E4) and the other that reacts with neo-epitope of HS, which occurs after heparitinase digestion of HS chains (3G10), we examined the serum and urinary concentrations of HS by enzyme-linked immunosorbent assay and performed immunohistochemical staining of glomeruli in diabetic patients with and without nephropathy. RESULTS: The level of urinary excretion of 10E4 binding HS/creatinine clearance was significantly reduced in diabetic patients when compared with that in nondiabetic subjects (P < 0.0001), and the level was more decreased in patients with overt nephropathy than in patients without overt nephropathy. No differences or only small differences were found between these groups in serum and urinary 3G10-binding HS and in serum 10E4-binding HS. Immunohistochemical staining with these antibodies was consistent with the findings in the urine. CONCLUSIONS: The results suggest that a decreased HS N-sulfation exists in the urine, which may reflect a structural change or an altered processing of HS within the GBM. Because N-sulfation plays a key role in determining the extent of sulfation within the HS chains, the decreased urinary 10E4-binding HS may have potential implications with regard to the development of diabetic nephropathy.

Adult↗
PubMed1999

Flow balance between the left and right cardiac output of an eccentric roller type total artificial heart.

We have made an eccentric roller type total artificial heart (ERTAH). The ERTAH is a positive-displacement device comparable to a DeBakey roller pump. Its left and right outputs are determined by the size of its blood chambers, and the ratio of its left and right output is almost constant. We focused on an interatrial shunt to achieve left-right balance. We have conducted numerical simulation, a mock test, and an acute animal experiment to analyze left-right heart balance during ERTAH operation. Numerical simulation was performed under conditions in which the flow of the left artificial heart was fixed at 6 L/min, the flow of the right artificial heart was varied from 4.8 to 6 L/min, and the interatrial resistance was also varied. The relationship between the interatrial shunt flow rate and the output of the left and right artificial hearts was balanced when the flow of the right artificial heart was at 5.45 L/min. In a mock test, 2 DeBakey roller pumps were connected to the left and right sides of a Donovan mock circulatory system, and an interatrial shunt was created between the inlet ports of the left and right roller pumps. The interatrial resistance of the mock system was varied from 7.7, to 4.3, and to 2.9 mm Hg x min/L when the inner diameter of the interatrial shunt was 6, 8, and 10 mm, respectively. As in the mock test, 2 roller pumps were used to bypass the right and left hearts of a goat weighing 60 kg. The flow rate of the left heart was almost constant (4.7 L/min). The flow of the right heart was approximately 4.1 L/min when the interatrial shunt flow rate was zero. A leading consideration was that the left to left shunt through the bronchial arteries in this goat was approximately 0.6 L/min. In developing the ERTAH, we considered that creating an interatrial shunt between the inlet ports of the ERTAH as well as making a difference between the chamber volumes might be effective in balancing the left-right sides of the artificial heart.

Animals↗
PubMed1999

Haemodynamics and oxygen tension in the microcirculation of ischaemic skin flaps after neural blockade and haemodilution.

The aim of this study was to evaluate the effects of neural blockade and extended normovolaemic haemodilution on haemodynamics and oxygenation in the microcirculation of ischaemic skin flaps using a recently developed island flap on the back of Syrian golden hamsters. One part of the flap was made ischaemic by inducing a random perfusion pattern following interruption of the axial blood supply. The model permitted quantitative assessment of the microhaemodynamics and oxygen tension in all microvascular segments by the use of intravital microscopy. Oxygen tension was measured with the phosphorescence decay method. Neural blockade was induced by applying 2% lidocaine to the neurovascular flap pedicle. Haemodilution was achieved by isovolaemic exchange of 50% of the total blood volume with dextran 70. One hour after surgery (baseline), centreline velocity was significantly reduced to 20-44% in all the microvessels in the randomly as compared to the axially perfused part, whereas the diameters were slightly larger (ns). In the control group, blood flow declined by 20-75% (P< 0.01 vs. baseline) over time in the entire flap. Flow reduction was significantly attenuated by haemodilution in the entire flap, but more pronounced in the ischaemic part. Neural blockade caused marked vasodilatation and significantly improved blood flow in the axially but not in randomly perfused microvessels. After 8 h, oxygen tension ranged from 4.0 to 6.1 mmHg in the axial part (means, ns between groups), whereas in the ischaemic part, it was 0.8-1.0 mmHg (P< vs. axial) in the control and neural blockade groups, and 1.7 mmHg (ns vs. axial and between groups) after haemodilution. Our findings indicate that neural blockade does not improve microcirculation and oxygenation in randomly perfused flap tissue because the sympathetic regulation of its microcirculation is overruled by autoregulatory mechanisms. Normovolaemic haemodilution, even after a 50% exchange, augments oxygenation in ischaemic flap tissue due to increased blood flow particularly in the randomly perfused tissue.

Analysis of Variance↗