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Biomedical subjects

M Hirata

Publications and source records attributed to M Hirata.

At least 217 records · Page 12Linked to original sources
PubMed1997

Hen egg-white lysozyme inhibits biological activities of lipopolysaccharides from periodontopathic bacteria.

Lysozyme has a bactericidal activity for some strains of Gram-positive bacteria, by enzymatic cleavage of peptidoglycans that constitute the cell wall. Hen egg-white lysozyme (HEL) was tested in vitro for effects on biological activities of lipopolysaccharides from periodontopathic Gram-negative bacteria. Actinobacillus actinomycetemcomitans, Prevotella intermedia and Porphyromonas gingivalis. HEL inhibited a wide range of activities of these lipopolysaccharides, including activation of Limulus amoebocyte lysate, stimulation of human leukocytes to secrete tumour necrosis factor-alpha, polyclonal activation of mouse B cells, and promotion of osteoclastic differentiation in mouse bone marrow cultures. The anti-endotoxic activity of HEL may be worthy of being intended for periodontal therapy.

Aggregatibacter actinomycetemcomitans↗
PubMed1997

Multiple brain gas embolism after ingestion of concentrated hydrogen peroxide.

We present a 63-year-old man who developed multiple brain infarction after ingesting a 35% hydrogen peroxide solution. Neurologic examination revealed left hemiparesis, primarily affecting the lower limb, and mild weakness of the right lower limb. Gadolinium-enhanced MRI revealed patchy bilateral brain lesions. Oxygen gas embolization is the likely cause of the brain infarctions.

Accidents↗
PubMed1997

Study on optimal fat content in total parenteral nutrition in partially hepatectomized rats.

In order to investigate the optimal fat content for total parenteral nutrition (TPN) solutions, male Wistar rats were subjected to 70% hepatectomy and then placed, for five days, on one of five TPN regimens in which fat represented 0%, 10%, 20%, 30% and 40%, respectively, of the total calorie content. As serum triglyceride levels in the fat-treated groups were lower than those in the non-treated normal rats, it was concluded that the administered fat was sufficiently hydrolyzed. The greater the fat content, the higher the regeneration rate of the remnant liver. Significant differences were found between the 0%-fat group and 20%-plus fat groups. Hepatic triglyceride level was significantly lower in the 20%-fat group. Hepatic protein level was significantly elevated in all fat-treated groups. Serum phospholipids and total cholesterol due to the lecithin contained in fat emulsion were significantly elevated in the 30 and 40%-fat groups, indicating that fat content of 30 and 40% was excessive. The results suggest that TPN containing fat is superior to fat-free TPN for liver regeneration after partial hepatectomy, and that optimal fat content is estimated to be about 20% of total calorie content in the case of this fat emulsion.

Animals↗
PubMed1997

[Development and transition of magnetic attachments--a literature review].

In the 1950 s, a new method of using magnets for the retainers of removable partial dentures (RPDs) was developed. It utilized magnetic attractive force instead of mechanical friction. However, the magnets used in those days were Alnico, Ferrite and/or Pt-Cobalt magnets and their retentive force was not strong enough to stabilize the dentures. Therefore, they gradually went out of use. In the middle of the 1970 s, Samarium Cobalt magnets, which have strong magnetic characteristics, were developed and introduced into dental field. In 1976, Sasaki first applied the samarium cobalt magnets to the retainers of PPDs. While in 1981, Mizutani, et al. first used well-fitted ferromagnetic alloy and the magnet for the purpose of stabilizing the RPD. Since then, many researchers have developed devices such as the magnetic retainer and the closed field magnetic attachment placed on the market in 1992. Now, as for the popular retainer of RPD, one can easily use a smaller yet stronger magnetic attachment which uses Neodium rather than Samarium Cobalt magnet.

Dental Alloys↗
PubMed1997

Inhibitory effect of circulating egg antigens on Schistosoma japonicum egg-induced granuloma formation.

Schistosoma japonicum produces an enormous quantity of eggs during infection. This study was conducted to examine the effect of egg-derived antigens on the development of granuloma formation around S. japonicum eggs in the livers of mice. When soluble egg antigen (SEA) (75 micrograms/mouse/day) was injected 3-4 times via a vein into mice implanted with laid eggs, the magnitude of tissue lesion was drastically inhibited when assessed at maximal occurrence (14 days after implantation of eggs), whereas adult worm antigen (AWA), rabbit hyperimmune serum against SEA, or bovine serum albumin (BSA) did not show any effect on either the cellularity or the magnitude. In contrast to intravenous injection, there was no effect from subcutaneous injections of SEA. When serum taken from heavily infected mice or rabbit was transferred, there was a considerable extent of inhibition. In addition, an immune complex fraction of infected rabbit serum was found to have a stronger inhibitory effect than the supernatant fraction. This study indicates that the amount of egg-derived circulating antigens has a crucial effect on the development of schistosome granuloma formation.

Animals↗
PubMed1997

Indoxyl sulfate stimulates renal synthesis of transforming growth factor-beta 1 and progression of renal failure.

We recently demonstrated that the administration of indoxyl sulfate (dietary protein metabolite) to 5/6-nephrectomized rats accelerated the progression of chronic renal failure by increasing the transforming growth factor (TGF)-beta 1 synthesis in the kidneys, which enhanced the renal expressions of tissue inhibitor of metalloproteinase (TIMP)-1 and type 1 collagen, leading to renal fibrosis. The aim of the present study was to clarify the mechanism by which the administration of indoxyl sulfate increases TGF-beta 1 in the kidneys of uremic rats. Since infiltrative monocytes are suggested to be an important source of TGF-beta 1 in tubulointerstitial fibrosis, we examined the effect of indoxyl sulfate administration to uremic rats on the renal gene expression of intercellular adhesion molecule (ICAM)-1, which is involved in the infiltration of monocytes to kidneys. Indoxyl sulfate administration was observed to enhance the mRNA levels of ICAM-1 as well as those of TGF-beta 1, TIMP-1 and pro alpha 1 (I) collagen in the renal cortex of 5/6-nephrectomized uremic rats. In addition, we demonstrated in vitro that the addition of indoxyl sulfate significantly increased the synthesis of TGF-beta 1 in cultured proximal tubular cells. Thus, the overload of indoxyl sulfate in uremic kidneys increased the infiltration of monocytes and directly increased the synthesis of TGF-beta 1 in proximal tubular cells.

Animals↗
PubMed1997

A case-control study of acute diarrheal disease among school-age children in southern Thailand.

We conducted a case-control study of school-age children in Phatthalung, a province in southern Thailand using a questionnaire to investigate associations of children's hygiene-related behavior and hygienic conditions in their homes with acute diarrheal disease. We compared 69 acute diarrhea (less than 7 days duration) cases that attended two hospitals in Phatthalung during August 1995 to June 1996 with 69 age-, sex- and address-matched controls in primary schools who had not suffered from diarrheal disease for the past one year before August 1995. Three factors were found to be significantly associated with acute diarrheal disease: farmer or gum planter as the occupation of father [Odds ratio (OR) 6.6; 95% confidence interval (CI) 1.7-26.1, p < 0.01], installation of a refrigerator in children's homes (OR 0.2; CI 0.1-0.8, p < 0.05), and drinking untreated water (OR 2.3; CI 0.9-6.1, p < 0.1). There was no significant difference for sources of drinking water between cases and controls. Considering the data on drinking water, the results indicated that there are some problems with quality of sources of drinking water. The results also suggested that having a refrigerator could have preventive effects on acute diarrheal disease, while inadequate behavior and unhygienic environment in the homes of farmers and gum planters might be related to acute diarrheal among school-age children.

Agriculture↗
PubMed1996

Testicular toxicity evaluation of arsenic-containing binary compound semiconductors, gallium arsenide and indium arsenide, in hamsters.

The testicular toxicities of gallium arsenide (GaAs), indium arsenide (InAs) and arsenic trioxide (As2O3) were examined by repetitive intratracheal instillation using hamsters. GaAs (7.7 mg/kg) and As2O3 (1.3 mg/kg) were instilled twice a week a total of 16 times and InAs (7.7 mg/kg) was instilled a total of 14 times. GaAs caused testicular spermatid retention and epididymal sperm reduction, though the degrees were less severe than those in rats shown in our previous experiment. InAs and As2O3 did not show any testicular toxicities. Serum arsenic concentration in GaAs-treated hamsters was less than half of that in As2O3-treated hamsters in which no testicular toxicities were found. Serum molar concentration of gallium was 32-times higher than that of arsenic in GaAs-treated hamsters. Therefore gallium may play a main role in the testicular toxicity of GaAs in hamsters.

Animals↗
PubMed1996

Limulus factor D, a 43-kDa protein isolated from horseshoe crab hemocytes, is a serine protease homologue with antimicrobial activity.

A glycoprotein (Mr = 43,000) from horseshoe crab hemocytes with antimicrobial activity against Gram-negative bacteria was purified. The internal peptide sequences coincided exactly with the deduced amino acid sequence of a cDNA clone, designated limulus factor D, which was isolated by screening a hemocyte cDNA library with an anti-human plasminogen antibody. The open reading frame codes for a precursor of factor D of 394 amino acid residues, including an NH2-terminal signal sequence. The COOH-terminal domain of factor D has significant sequence homology with the catalytic domain of mammalian serine proteases, in particular with human tissue plasminogen activator (32% identity), except for the substitution of Ser of the active site triad to Gly. Factor D has a unique NH2-terminal domain with weak sequence homology with part of the mammalian interleukin-6 receptor alpha-chain. Factor D is likely to have an important role in host defense mechanisms.

Amino Acid Sequence↗
PubMed1996

Localization of a high-affinity inositol 1,4,5-trisphosphate/inositol 1,4,5,6-tetrakisphosphate binding domain to the pleckstrin homology module of a new 130 kDa protein: characterization of the determinants of structural specificity.

We have previously identified a novel 130 kDa protein (p130) which binds Ins(1,4,5)P3 and shares 38% sequence identity with phospholipase C-delta 1 [Kanematsu, Misumi, Watanabe, Ozaki, Koga, Iwanaga, Ikehara and Hirata (1996) Biochem. J. 313, 319-325]. We have now transfected COS-1 cells with genes encoding the entire length of the molecule or one of several truncated mutants, in order to locate the region for binding of Ins(1,4,5)P3. Deletion of N-terminal residues 116-232, the region which corresponds to the pleckstrin homology (PH) domain of the molecule, completely abolished binding activity. This result was confirmed when the PH domain itself (residues 95-232), isolated from a bacterial expression system, was found to bind [3H]Ins(1,4,5)P3. We also found that Ins(1,4,5,6)P4 was as efficacious as Ins(1,4,5)P3 in displacing [3H]Ins(1,4,5)P3, suggesting that these two polyphosphates bind to p130 with similar affinity. This conclusion was confirmed by direct binding studies using [3H]Ins(1,4,5,6)P4 with high specific radioactivity which we prepared ourselves. Binding specificity was also examined with a variety of inositol phosphate derivatives. As is the case with other PH domains characterized to date, we found that the 4,5-vicinal phosphate pair was an essential determinant of ligand specificity. However, the PH domain of p130 exhibited some novel features. For example, the 3- and/or 6-phosphates could also contribute to overall binding; this contrasts with some other PH domains where these phosphate groups decrease ligand affinity by imposing a steric constraint. Secondly, a free monoester 1-phosphate substantially increased binding affinity, which is a situation so far unique to the PH domain of p130.

Animals↗
PubMed1996

Cytomegalovirus antibody status and renal transplantation: 1987-1994.

We examined graft and patient survival rates of 47,146 patients in the United Network for Organ Sharing registry following transplants between donors and recipients who were cytomegalovirus (CMV) antibody negative and positive. CMV positivity increased with age to about 80% in patients over 60. Seropositivity was seen in 80% of Asians, 71% of African Americans, and 56% of Caucasians. In all age groups, females had a slightly higher incidence of positivity than males. Transplants involving CMV-positive donors resulted in lower graft survival rates than those with CMV-negative donors. This occurred regardless of whether the recipient was CMV negative or positive. The greatest effect was on patient survival rate, which, in turn, adversely affected graft survival rate. The CMV-positive-donor effect was primarily noted in (1) Caucasian recipients, (2) patients with HLA-A,B,DR mismatches, and (3) patients older than 15 years of age. In contrast, CMV-positive donors were not a risk factor for African American and Hispanic patients, CMV-positive Asian patients, patients younger than 16 years of age, and patients with no HLA-A,B,DR antigen mismatches. In conclusion, a kidney from a CMV-positive donor is a risk factor for certain patients and currently yields about a 4% overall lower graft survival rate at 3 years than a kidney from a CMV-negative donor.

Adolescent↗
PubMed1996

The effect of pravastatin on acute rejection after kidney transplantation--a pilot study.

Hyperlipidemia is an important complication of kidney transplantation affecting up to 74% of recipients. HMG-CoA reductase inhibitors are reported to provide safe and effective treatment for this problem. A recent study suggests that pravastatin, an HMG-CoA reductase inhibitor, also decreases the incidence of both clinically severe acute rejection episodes and natural killer cell cytotoxicity after orthotopic heart transplantation. We have performed a prospective randomized pilot study of the effect of pravastatin on these same parameters after cadaveric kidney transplantation. Graft recipients were randomized to receive pravastatin after transplantation or no pravastatin (24 patients in each group) in addition to routine cyclosporine and prednisone immunosuppression. Lipid levels, acute rejection episodes and serial natural killer cell cytotoxicities were followed for 4 months after the transplant. At the end of the study period, pravastatin had successfully controlled mean total cholesterol levels (202.6 +/- 9.3 vs. 236.5 +/- 11.9 mg/dl, P < 0.02), LDL levels (107.9 +/- 6.6 vs.149.6 +/- 10.7 mg/dl, P < 0.002), and triglyceride levels (118.8 +/- 14.2 vs. 157.2 +/- 13.8 mg/dl, P < 0.05). In addition, the pravastatin-treated group experienced a reduction in the incidence of biopsy-proven acute rejection episodes (25% vs. 58%, P = 0.01), the incidence of multiple rejections episodes (P < 0.05), and the use of both pulse methylprednisolone (P = 0.01) and OKT3 (P = 0.02). Mean natural killer cell cytotoxicity was similarly reduced (11.3 +/- 1.6 vs. 20.0 +/- 2.0% lysis of K562 target cells, P < 0.002). These data suggest that pravastatin exerts an additional immunosuppressive effect in kidney transplant recipients treated with cyclosporine-based immunosuppression.

Adult↗
PubMed1996

Patient death after renal transplantation--an analysis of its role in graft outcome.

Whether patient deaths among renal transplant recipients should be counted as transplant failures when they occur while the transplant is still functioning is a controversial issue. Analyses of more than 45,000 first cadaver transplants reported to the UNOS Scientific Renal Transplant Registry between October 1987 and March 1995 showed that deaths among transplant recipients were strongly associated with the patient's age and presence of insulin-dependent diabetes. Other factors associated with poor early graft function were also associated with a significantly increased risk of death. Deaths within the first 5 years increased from 9% of recipients aged 2-15 to 30% of those over age 45 (P < 0.001). Deaths with a functioning graft occurred in 2% of the youngest patients and 13% in the older age group (P < 0.001). Among diabetics, 32% died within 5 years (12% with a functioning graft) compared with 10% (6% with graft function) of patients with glomerulonephritis (P < 0.001). When the transplanted kidney failed to function immediately or the patient required dialysis during the first week after transplant, 30% of patients died within 5 years compared with 20% when the graft functioned (P < 0.001). There was no difference in the percentage of deaths with a functioning graft. We conclude that deaths among renal transplant recipients follow an expected pattern in which the likelihood of death increases with age and diabetes.

Adolescent↗
PubMed1996

Cholecystokinin receptor antagonist, loxiglumide, inhibits invasiveness of human pancreatic cancer cell lines.

Recently, cholecystokinin has been reported to be important in regulating the growth of pancreatic cancer. We investigated the effect of loxiglumide (LXG), a cholecystokinin receptor antagonist, on the invasiveness of two human pancreatic cancer cell lines. Cells were treated with LXG for 24 h, and examined in the invasion assay. The expression and activity of MMP-9 in supernatants from cancer cells were analyzed by Western blotting and zymogram. Interestingly, the invasiveness of cancer cells and expression of MMP-9 were decreased by LXG in a dose-dependent manner. LXG may be a useful therapeutic agent against pancreatic cancer.

Blotting, Western↗
PubMed1996

Growth inhibition of human leukemic cells by WT1 (Wilms tumor gene) antisense oligodeoxynucleotides: implications for the involvement of WT1 in leukemogenesis.

We have previously reported expression of WT1 in acute leukemia. To elucidate its biological significance, we examined the effect of the suppression of the WT1 expression by WT1 antisense oligomers on the growth of the leukemic cells expressing WT1. When 20 different WT1 antisense (AS) oligomers covering from the 5' cap sites of the WT1 gene to the 3' end were examined for the inhibitory effect on the growth of K562 cells expressing WT1, four WT1 AS oligomers inhibited the cell growth, whereas WT1 sense and random sequence oligomers had no effect on the cell growth of K562. Moreover, WT1 AS oligomers significantly inhibited the growth of the clonogenic cells of fresh leukemic cells in six of 14 patients with acute myeloid leukemia, in one of two patients with chronic myelogenous leukemia (CML) chronic phase, and in one of one patient with CML blastic crisis. However, these oligomers did not inhibit normal colony-forming unit-granulocyte-macrophage. Western blot analysis clearly demonstrated the significant reduction in the WT1 protein levels in the K562 and fresh leukemic cells that were treated with the WT1 AS oligomers, confirming that the inhibitory effect of the WT1 AS oligomers on the cell growth operates via the reduction in the WT1 protein levels. These results show that WT1 plays an important role in leukemogenesis.

Base Sequence↗
PubMed1996

Mapping of the genes encoding mouse prostaglandin D, E, and F and prostacyclin receptors.

Prostaglandins and prostacyclin are metabolites of arachidonic acid and exert a variety of actions to maintain local homeostasis in the body. Their actions are mediated by cell surface receptors specific to the respective ligands. Using a panel of interspecific back-cross mice, we have mapped the prostaglandin D receptor gene (Ptgdr), prostaglandin E receptor subtype EP(1) gene (Ptgerepl), prostaglandin F receptor gene (Ptgfr), and prostacyclin receptor gene (Ptgir). Ptgdr mapped to proximal Chr 14, Ptgfr mapped to distal Chr 3, Ptgerepl mapped to middle Chr 8, and Ptgir mapped to proximal Chr 7.

Animals↗