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Biomedical subjects

H Sakai

Publications and source records attributed to H Sakai.

At least 469 records · Page 26Linked to original sources
PubMed1997

Convulsions in hemodialysis (HD) patients with elevated polymorphonuclear leukocyte elastase (PMNE) levels.

Eight hemodialysis (HD) patients with convulsions of unknown cause were monitored for serum levels of uremic toxins such as methylguanidine(MG), and polymorphonuclear leukocyte elastase (PMNE). Twenty HD patients without convulsions served as controls. In the convulsion group, MG and PMNE were high. In 2 patients, convulsions subsided after daily hemodiafiltration (HDF). Although PMNE was thought to be a mediator of injury in the present series, no significant correlation was found between PMNE and either neutrophil numbers or endotoxin levels. PMNE may indicate the over production of cytokines not associated with serious infection or septicemia. In patients with renal failure and complications of unknown cause, intensified dialysis therapy such as frequent HDF may be useful when combined with treatment of the underlying disease producing the toxins. PMNE measurement is useful in assessing the uremia caused by high cytokine levels and, together with methylguanidin (MG) serum levels, can indicate the severity of the convulsion.

Aged↗
PubMed1996

Construction and characterization of a recombinant adenovirus vector carrying the human preproinsulin gene under the control of the metallothionein gene promoter.

A new adenovirus vector carrying human-preproinsulin (h-PPI) genomic DNA, which was placed under the control of the mouse metallothionein gene promoter, was constructed. In the recombinant virus-infected cells, h-PPI gene expression increased as a function of ZnSO4 concentration. Reversed-phase high-performance liquid chromatography analysis revealed that the recombinant adenovirus-infected cells secreted immature insulin containing proinsulin and incorrectly processed insulin. Tyrosyl phosphorylation of human insulin receptor substrate 1 occurred when HepG2 cells were treated with the cultured medium, indicating that the h-PPI gene product was functionally active in vitro. We also examined the biological activity of the product using diabetic severe combined immunodeficient mice and confirmed that the h-PPI gene product reduced the blood glucose concentration in vivo. This study suggests that the adenovirus vector can be used to express a foreign gene under the control of an external promoter in various human cells.

Adenoviridae↗
PubMed1996

Thermolabile beta-2 macroglycoprotein (Hakata antigen) in liver disease: biochemical and immunohistochemical study.

Thermolabile beta-2 macroglycoprotein is a novel serum protein that was detected by an autoantibody in sera of a Japanese woman with systemic lupus erythematosus. We developed an enzyme-linked immunosorbent assay for this glycoprotein and measured its serum levels in patients with chronic liver disease. There were significant correlations between serum levels of this glycoprotein and those of albumin and cholinesterase. The serum levels of TL beta 2MG decreased with increasing severity of cirrhosis. Immunohistochemical staining using monoclonal anti-thermolabile beta-2 macroglycoprotein antibody revealed positive staining in the cytoplasm of the hepatocytes. These data strongly suggested that hepatocyte may be one of the production sites of this glycoprotein. Measurement of serum levels of this glycoprotein was useful for evaluation of hepatic function in chronic liver disease.

Adult↗
PubMed1996

Differential effect of interleukin-1 alpha on rat hepatic cytochrome P450 monooxygenases.

Administration of recombinant human interleukin-1 alpha to adult male rats caused a significant reduction in the levels of hepatic cytochrome P450 and P450 reductase activity at 24 h after the treatment. The mRNAs for cytochrome P450 1A2 and 2E1 were reduced more than 70% at 12 h after administration of interleukin-1 alpha and remained decreased even after 48 h. By contrast, cytochrome P450 2C11 mRNA was reduced only by 30% at 12 h after the treatment and returned to the control levels by 48 h, suggesting that interleukin-1 alpha has a differential effect on the expression of P450 mRNAs. Aniline hydroxylase, benzphetamine N-demethylase and 7-ethoxycoumarin O-deethylase activities were significantly decreased at 24 h after interleukin-1 alpha treatment. The proteins for cytochrome P450 1A2 and 2E1 were reduced by about 50% at 24 h after interleukin-1 alpha treatment.

7-Alkoxycoumarin O-Dealkylase↗
PubMed1996

Allosteric activation of L-lactate dehydrogenase analyzed by hybrid enzymes with effector-sensitive and -insensitive subunits.

Subunit-hybrid enzymes of mutant tetrameric L-lactate dehydrogenases from Bifidobacterium longum were studied in an examination of the mechanism of allosteric activation by fructose 1,6-bisphosphate. We earlier developed an in vivo method for subunit hybridization in Escherichia coli and the hybrids formed were a mixture with different subunit compositions. The B. longum hybrids were separated by anion-exchange chromatography with a mutational tag. Hybrids formed between fructose 1,6-bisphosphate-desensitized subunits and wild-type subunits and also between fructose 1, 6-bisphosphate-desensitized subunits and catalytically inactive subunits. Kinetic analyses of the hybrid enzymes showed that (i) those residues from two symmetrically related subunits that constituted the fructose 1,6-bisphosphate-binding site could bind fructose 1,6-bisphosphate and activate the enzyme only if intact, (ii) hybrids with only one functional fructose 1, 6-bisphosphate-binding site were fully sensitive to fructose 1, 6-bisphosphate, but the allosteric equilibrium had shifted partially, and (iii) activation by fructose 1,6-bisphosphate at the fructose 1, 6-bisphosphate-binding site was transmitted to the active sites through a quaternary structural change, not through direct conformational change within a subunit. These results are evidence of the validity of the concerted allosteric model of this enzyme based on T- and R-state structures in the same crystal lattice proposed earlier.

Allosteric Regulation↗
PubMed1996

Age-related and dexamethasone-induced changes in cathepsins E and D in rat thymic and splenic cells.

Age-related and dexamethasone (DEX)-induced changes in the cellular levels, distributions, and molecular forms of two distinct intracellular aspartic proteinases, cathepsin E (CE) and cathepsin D (CD), were investigated in rat thymus and spleen by immunohistochemical and quantitative analyses. In the thymus, CE was predominantly restricted to thymocytes and macrophage-like cells, whereas CD was associated mainly with the stromal cells. The increased thymic CE level observed in young rats up to 8 weeks of age was markedly decreased in aged rats (78-80 weeks of age), in accordance with the involution of the thymus, while there was little difference in the thymic CD level between young and aged rats. Subcutaneous administration of DEX also caused a marked decrease of the thymic CE level in response to the depletion of thymocytes. In contrast, a great accumulation of CD occurred in the thymic stromal cells after DEX treatment. Immunoblotting analyses revealed that CE in thymocytes isolated from young rats consisted predominantly of a 46-kDa proform which was greatly converted into a 42-kDa mature form in DEX-treated thymocytes. This conversion, however, was scarcely observed during the normal aging process. In the spleen, CE was also abundant in macrophage-like cells and lymphocytes and its level was not significantly changed between young and aged rats. However, DEX treatment caused a marked decrease of the splenic CE and CD levels in accordance with the depletion of the white pulp. Among the lymphoid cell types examined, splenic B cells were the most abundant in CE. The CE level in thymocytes and splenic T-cells was more than twice that in circulating lymphocytes. We concluded that CE is related to the process of activation-induced lymphocyte depletion.

Aging↗
PubMed1996

Differential mRNA expression of phospholipase D (PLD) isozymes during cAMP-induced differentiation in C6 glioma cells.

GTP gamma S-dependent phospholipase D (PLD) activity time-dependently increased during differentiation of rat C6 glioma cells to astrocytic phenotypes induced by dibutyryl cyclic AMP (dbcAMP)/theophylline. The changes in PLD mRNA level were examined by reverse transcriptase-polymerase chain reaction (RT-PCR) method using the degenerate primers designed based on two conserved amino acid sequences in PLDs of human and yeast. The amplified three DNA fragments (tentatively termed as rPLDa, b, and c) contained the conserved regions present in PLDs of various organisms. RT-PCR using non-degenerate primers showed that rPLDa mRNA increased within 12h following treatment with dbcAMP, reaching a broad plateau and then returned to the initial level at 48h. In contrast, the level of rPLDb mRNA showed a concurrent decrease. rPLDc decreased in a time-dependent manner. These results suggest that the expression of PLD mRNAs are differentially regulated during differentiation in C6 glioma cells.

Amino Acid Sequence↗
PubMed1996

A dnaA box can functionally substitute for the priming signals in the oriV of the broad host-range plasmid RSF1010.

The initiation of replication from oriV RSF1010, the replication origin of the broad host-range plasmid RSF1010, depends on RepA (helicase), RepB' (primase), and RepC (initiator protein), encoded by RSF1010 itself, while this initiation event in E. coli is independent of dnaA, dnaB, dnaC, and dnaG [Scherzinger et al. (1984) Proc. Natl. Acad. Sci. USA 81, 654-658; Scholz et al. (1985) in: Plasmids in Bacteria, pp. 243-259, Plenum, New York; Haring and Scherzinger (1989) in: Promiscuous Plasmids of Gram-negative Bacteria, pp. 95-124, Academic Press, London; Scherzinger et al. (1991) Nucl. Acids Res. 19, 1203-1211]. We showed in this work that a newly constructed origin consisting of an oriV RSF1010 and a DnaA protein binding site, the dnaA box, inserted near oriV RSF1010 (oriV RSF1010-dnaA box) could function without RepB' primase, but required RepA and RepC. This oriV RsF1010-dnaA box could not replicate in a dnaA46 strain in which only RepA and RepC were supplied, even at a permissive temperature. These results indicate that an inserted dnaA box can functionally substitute for the RSF1010-specific ssi signals, the RepB' dependent priming signals in oriV RSF1010, and can direct a priming pathway different from the RSF1010-specific one, but related to DnaA protein.

Bacterial Proteins↗
PubMed1996

Suppressed expression of CD44 variant isoforms during human glioma A172 cell differentiation induced by cyclic AMP.

CD44 is a major receptor for hyaluronic acid, which is the most frequent route of malignant glioma invasion. Multiple isoforms of CD44 are generated by alternative mRNA splicing. We have examined differential expression of CD44 variant isoforms (CD44vs) during dibutyryl cyclic AMP (dbcAMP)/theophylline-induced differentiation of human glioma A172 cells using reverse transcriptase-polymerase chain reaction (RT-PCR). Treatment of cells with dbcAMP and theophylline caused decreased expression of all CD44 isoforms after 24 h. The CD44 standard form was observed to return to the unstimulated level after 72 h, whereas the variant isoforms, CD44 8v-10v and 10v, remained at the low level after 24-72 h. Changes of CD44vs were correlated with the level of expression of c-jun. These results suggested that the expression patterns of CD44vs might correlate with cellular differentiation in human glioma cells.).

Brain Neoplasms↗
PubMed1996

Regulation of insulin-like growth factor-I expression in mouse preadipocyte Ob1771 cells.

In mouse preadipocyte Ob1771 cells, transcription of the insulin-like growth factor-I (IGF-I) gene was stimulated by growth hormone (GH), and IGF-I protein combined with GH in medium was required for their differentiation to adipocytes. During induction of the differentiation, the intracellular expression of each class of IGF-I mRNA was analyzed by reverse transcriptase-polymerase chain reaction. When the cells were cultured in the presence of GH, the class 1del. IGF-I mRNA was a major molecular species among IGF-I mRNAs. In the presence of both GH and IGF-I, the splicing pattern of IGF-I mRNA changed from class 1del. to class 1. Moreover, as detected by Western blotting, the IGF-I protein was present in cells and in the medium only when the cells were cultured in the presence of both GH and IGF-I. We found that IGF-I secreted from Ob1771 cells could act in an autocrine/paracrine fashion and induce the differentiation of other Ob1771 cells. It was demonstrated that the translation efficiency of class 1 mRNA was higher than that of class 1del. mRNA in vitro. These results suggested that stimulation with exogenous IGF-I in the presence of GH was required for the production of class 1 IGF-I mRNA and that the production of the IGF-I protein was activated by increasing the translation efficiency through shifting the splicing pattern of IGF-I mRNA from class 1del. to class 1. Exogenous IGF-I triggered the differentiation by initiating the synthesis of endogenous IGF-I.

Adipocytes↗
PubMed1996

Cooperative clinical trial of photodynamic therapy with photofrin II and excimer dye laser for early gastric cancer.

BACKGROUND AND OBJECTIVE: Photodynamic therapy (PDT) is a recently developed endoscopic method for treating malignant tumors. For obtaining more photodynamic action with less thermal effect, we employed as the excitation light source for PDT an excimer dye laser, which is a pulsed laser with extremely high peak power, instead of an argon dye laser, which is a continuous wave laser and has been used conventionally. STUDY DESIGN/MATERIALS AND METHODS: The effect of PDT using Photofrin II and the excimer dye laser was evaluated in 27 patients with early gastric cancer. RESULTS: Complete responses (CR) were obtained in 88% of 24 assessable patients and the response rate was 100%. CR was observed in all cases of lesions of superficial depressed type without ulceration and/or with tumor diameter less than 2 cm. Regarding toxicity, mild cutaneous reaction and photosensitivity were seen and lasted several weeks. There were no serious abnormalities in laboratory tests. CONCLUSION: We conclude that PDT is a promising modality for early gastric cancer.

Aged↗
PubMed1996

A safe clinical system for nitric oxide inhalation therapy for pediatric patients.

A safe clinical system for nitric oxide (NO) inhalation therapy was developed. The system consists of three parts: a NO controller, a NO monitor, and a patient circuit. NO gas flow and carrier gas flow are controlled by a special rust-proof thermal mass flowmeter. Standard gas quality NO gas (10,000 ppm, balance nitrogen) is used. The outlet of the NO gas tank is connected to the distal end of a heated humidifer that is very close (12 mL) to the patient, to decrease acidic water precipitation and decrease contact time between NO and oxygen (O2). Fail-safe mechanisms to prevent the delivery of a hypoxic mixture or excessive NO concentration are incorporated. Inspiratory NO concentration is continuously monitored by a modified electrochemical NO meter. The patient circuit consists of a breathing circuit and a ventilator with a scavenging unit. A modified Mapleson D type circuit is used. Fresh gas, humidified and mixed with NO, is introduced to the patient connection port. A mechanical ventilator, either of conventional or of high-frequency oscillation type, is connected to the expiratory limb of the Mapleson D circuit. A coaxial scavenging unit including activated charcoal is placed in between the expiratory limb and the ventilator. The adjustment of inspiratory NO concentration (y) was accurate over a wide range (1-80 ppm) of concentrations (x) (y = 0.36 + 0.96x, R2 = 0.999, n = 45) and showed good agreement with the chemiluminescence method. Inspiratory nitrous oxide (NO2) concentration was less than 0.3 ppm, and acidic water accumulation as measured by NO2- and NO3- was less than 5 ppm, even at an extremely high NO concentration of 80 ppm with an FiO2 of 1.0 and 10 L/min of fresh gas flow. Environmental NO and NO2 concentrations in the ICU remained below 0.005 and 0.05 ppm, respectively. This system was used clinically on 214 pediatric patients and proved to be accurate, safe, and useful.

Adolescent↗
PubMed1996

Histopathological response to preoperative chemotherapy including 5-fluorouracil additionally assessed by immunocytochemical and pharmacologic parameters in patients with advanced gastric cancer.

To investigate quantitative methods for assessing the response to preoperative downstaging chemotherapy (PDC), the immunocytochemical expression of proliferating cell nuclear antigen (PCNA) and bromodeoxyuridine (BrdU) as well as a pharmacologic study of the rate of thymidylate synthetase inhibition (TSIR) were studied in resected specimens obtained from patients with advanced gastric cancer. Fifty-one patients with advanced gastric cancer who received PDC (30 with 5-fluorouracil peroral administration and the other 21 with intravenous administration of 5-fluorouracil and cisplatin) were studied. The labeling index of PCNA (PCNA-LI) and BrdU were measured. The PCNA suppression (PCNA-S), which was measured by both the values of prechemotherapeutic PCNA-LI in endoscopically biopsied specimens and postchemotherapeutic PCNA-LI in resected specimens, was also examined. TSIR was measured by a protein-bound radiochemical method. We compared the above-mentioned parameters with the histopathological response to PDC according to the General Rules for Gastric Cancer Study. In the patients with peroral 5-flurorouracil, a stepwise regression analysis showed that TSIR is a significantly effective for determining the histopathological response to PDC. In the patients with 5-fluorouracil and cisplatin, PCNA-S was the most effective indicator of the histopathological response to PDC, as shown by a stepwise regression analysis. The present study thus showed that both TSIR and PCNA-S were effective additional indicators of the histopathological response to PDC.

Administration, Oral↗
PubMed1996

A case of transverse colon cancer secondarily involving the liver, duodenum, and pancreas.

A 68-year-old woman presented with transverse colon cancer invading the liver, duodenum, and pancreas. The patient underwent a curative resection including a right hemicolectomy, partial hepatectomy, and pancreaticoduodenectomy (PD). The pathological examination showed adenocarcinoma of the colon with a direct extension into the duodenum, liver, and pancreas. Several lymph nodes were also involved. The patient is still alive and disease-free 2 years and 6 months after the operation. This case illustrates that even in patients with locally advanced colon cancer, a favorable prognosis can be obtained by aggressive surgery incorporating the resection of the adjacent involved organs.

Adenocarcinoma↗
PubMed1996

The majority of T lymphocytes are polyclonal during the chronic phase of chronic myelogenous leukemia.

To clarify the extent of cell lineage involvement in chronic myelogenous leukemia (CML), we investigated the bcr gene rearrangement and clonality using the X-chromosome-linked restriction fragment length polymorphism (RFLP) methylation method in T lymphocytes and granulocytes. We examined the granulocyte and T-cell fractions from the peripheral blood of seven female patients with CML during the chronic phase; patients were heterozygous for RFLPs at the phosphoglycerate kinase (PGK) or the hypoxanthine phosphoribosyltransferase (HPRT) gene. RFLP-methylation analysis of granulocytes demonstrated a monoclonal pattern in six of the seven patients and a rearranged bcr gene in all seven patients. In contrast, T lymphocytes exhibited a polyclonal pattern in six cases; in one case, a faint band was observed following methyl-sensitive enzyme cleavage. The bcr gene analysis in T lymphocytes showed the germline in every case. Our results indicate that the majority of T lymphocytes are polyclonal during the chronic phase of CML and confirm previous reports based on glucose-6-phosphate dehydrogenase, cytogenetic, and bcr rearrangement analyses.

Adult↗
PubMed1996

Altered synthesis of interferon-gamma and expression of interferon-gamma receptor by peripheral blood mononuclear cells from patients with IgA nephropathy and non-IgA proliferative glomerulonephritis.

Previously we reported disease-specific interaction between interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) in patients with IgA nephropathy (IgAN), suggesting the existence of unusual T cell behavior in this disease. In the present study, we investigated characteristic synthesis of interferon-gamma (IFN-gamma) and expression of IFN-gamma receptor (IFN-gamma R) in the peripheral blood mononuclear cells (PBMC) from patients with IgAN and other chronic proliferative glomerulonephritis (PGN). Heparinized peripheral blood samples were obtained from 38 patients with chronic mesangial proliferative glomerulonephritis (CGN; including 24 with IgA nephropathy) and 20 healthy controls. PBMC were isolated by gradient centrifugation and fragments were cultured in Iscove's modified Dulbecco's medium (IMDM) supplemented with 10% fetal calf serum (FCS) for 72 hr. IFN-gamma concentrations in supernatants were evaluated by the enzyme-linked immunosorbent assay (ELISA). Other parts of PBMC pellets were reacted with anti-human IFN-gamma R monoclonal antibody and FITC-labeled anti-mouse second antibody for analysis of IFN-gamma R expression on these cells by FACScan. The remaining PBMC were fractionated into CD4+ T cells, CD8+ T cells, B cells, NK, cells and macrophages using the MACS cell sorting system. The isolated cells were evaluated for IFN-gamma or IFN-gamma R mRNA expression by the semiquantitative RT-PCR method. In vitro IFN-gamma synthesis was enhanced in patients with CGN, and NK cells were revealed to be responsible for such enhancement. On the other hand, the expression of IFN-gamma R on macrophages was suppressed in CGN patients. These results suggest that impairment of regulation of the IFN-gamma system might be involved in the development of CGN.

Antigens, CD↗
PubMed1996

Inhibitory effect of 1 alpha,25-dihydroxyvitamin D3 on mast cell proliferation and A23187-induced histamine release, also accompanied by a decreased c-kit receptor.

Using mouse peritoneal mast cells, we investigated the effects of 1 alpha,25-dihydroxyvitamin D3 (calcitriol) on mast cell proliferation and histamine release. Calcitriol did not affect IL-3/IL-4-dependent mast cell proliferation, but it selectively inhibited stem cell factor-dependent mast cell proliferation and colony formation. Immunohistochemical and immunoblot analyses revealed that calcitriol treatment reduced expression of purified peritoneal mast cell c-kit protein. Using a mast cell line, MC/9, both c-kit protein and c-kit mRNA transcript were seen to be reduced following calcitriol treatment. Calcitriol also reduced histamine release induced by calcium ionophore A23187. In contrast, anti-IgE antibody-dependent histamine release was not affected by calcitriol. Our results indicate that calcitriol inhibits mast cell proliferation and A23187-induced histamine release that might be associated with a decreased expression of c-kit receptor.

Animals↗