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Biomedical subjects

S Nagafuchi

Publications and source records attributed to S Nagafuchi.

At least 109 records · Page 6Linked to original sources
PubMed1985

The relationship between molecular and cellular repair from potentially lethal damage induced by N-methyl-N'-nitro-N-nitrosoguanidine in Chinese hamster V79 cells.

The relationship between molecular and cellular repair from potentially lethal damage (PLD) induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) was investigated in exponentially growing V79 Chinese hamster cells. We compared the repair processes by an alkaline sucrose sedimentation analysis and a colony formation assay. MNNG-treated cells were exposed to the conditioned medium (CM) from density-inhibited plateau-phase V79 cell cultures, as a post-treatment for the induction of PLD repair. When MNNG-treated cells were postincubated in CM, cell survival continuously increased for 18 h, and during this period, DNA replication was substantially suppressed. CM did not inhibit the rejoining of the single-strand breaks of parental DNA. Rather, parental DNA fragments sedimented more rapidly when postincubated in CM than in fresh medium. These data indicate that cellular recovery from MNNG-induced PLD increases in proportion to the resealing of MNNG-induced single-strand breaks of DNA during the suppression of DNA replication, suggesting that excision repair is involved in the PLD repair process.

Animals↗
PubMed1985

Hemoglobin Rahere, a human hemoglobin variant with amino acid substitution at the 2,3-diphosphoglycerate binding site. Functional consequences of the alteration and effects of bezafibrate on the oxygen bindings.

We encountered an abnormal hemoglobin (Rahere), with a threonine residue replacing the beta 82 (EF6) lysine residue at the binding site of 2,3-diphosphoglycerate, which was responsible for overt erythrocytosis in two individuals of a Japanese family. Hemoglobin Rahere shows a lower oxygen affinity on the binding of 2,3-diphosphoglycerate or chloride ions than hemoglobin A. Although a decrease in the positive charge density at the binding sites of 2,3-diphosphoglycerate in hemoglobin Rahere apparently shifts the allosteric equilibrium toward the low affinity state, it greatly diminishes the cofactor effects by anions. The oxygen affinity of the patient's erythrocytes is substantially lowered by the presence of bezafibrate, which combines with sites different from those of 2,3-diphosphoglycerate in either hemoglobin Rahere or hemoglobin A.

2,3-Diphosphoglycerate↗
PubMed1985

Delayed type hypersensitivity (DTH) skin reaction to hepatitis B surface antigen (HBsAg) in patients with type B acute and chronic hepatitis.

Skin reactivity to HBsAg was studied in patients with type B acute and chronic hepatitis and in healthy controls. HBsAg preparations containing 50 micrograms/ml of antigen both with and without alum elicited positive skin reactions in all seven anti-HBs+ persons. Histological examination of skin tissue from the reactive area using monoclonal antibodies to the cell surface of lymphocytes revealed accumulation of Leu-3a positive lymphocytes, showing that the inflammation was a typical delayed type hypersensitivity (DTH) reaction. Irrespective of the presence of HBeAg and anti-HBe, patients with chronic type B hepatitis responded clearly to PPD and SK/SD antigens, whereas they did not exhibit DTH skin reactivity to HBsAg. In contrast, although patients with acute type B hepatitis did not exhibit specific DTH a reaction to HBsAg in the acute period, they began to develop DTH skin reactivity to HBsAg in the convalescent phase of the disease preceding the appearance of anti-HBs antibody. It is suggested that DTH reaction to HBsAg might play an important role in the pathogenesis of type B viral hepatitis.

Acute Disease↗
PubMed1985

[Clinical studies on SM-4300].

Use of SM-4300, which is a newly developed human immunoglobulin preparation for intravenous administration, has clinically been evaluated in the patients with severe or intractable bacterial infections. Of total 13 cases of the admitted patients at the 1st department of internal medicine, faculty of medicine, Kyushu university, 10-pneumonia case were associated with blood diseases like acute myelocytic leukemia (AML) and multiple myeloma (MM), and in addition, with other underlying diseases like lung cancer and bronchiectasis, 1 was prosthetic valve endocarditis, 1 cholecystitis associated with pericarditis and 1 fever of undetermined origin (FUO). SM-4300 of 5 g single bolus or 3 daily doses of 2.5 g per day were infused with chemotherapy drugs preceedingly administered for more than 3 days and the results were evaluated; good in 4, fair 4, poor 2 and unknown 3, and the efficacy rate was 40%. Bacteriologically, the results were decreased in 1, persisted 1 and the majority was unknown. Observed were no side reactions nor the changes in clinical examination variables incurred by this drug. It is therefore considered that SM-4300 is of use for the treatment of intractable bacterial infections when used with antibiotics.

Adult↗
PubMed1984

Development of DTH skin reaction to HBsAg in individuals immunized with HB vaccine.

To examine the temporal relationship between the DTH skin reaction to HBsAg and antibody response to HBsAg, serial skin tests for HBsAg were carried out on seven individuals immunized with HB vaccine. All cases developed both a skin reaction and antibody response. In many cases, the DTH skin reaction appeared four weeks before the antibody response. These data suggest that DTH skin reaction may be a more sensitive method than humoral antibody assessment for monitoring the success of vaccination.

Adult↗
PubMed1984

The role of thymic immunity and insulitis in the development of streptozocin-induced diabetes in mice.

This article is concerned with the role of thymic immunity in the development of diabetes experimentally induced by multiple injections of subdiabetogenic doses of streptozocin (STZ). Euthymic +/+, +/nu, and athymic nu/nu mice of CD-1 and BALB/cAJcl origin were studied. Daily intraperitoneal (i.p.) injections of 30 mg/kg body wt of STZ for 5 consecutive days in CD-1 +/+ and +/nu mice resulted in hyperglycemia and mononuclear cell infiltrations of islets (insulitis). The CD-1 nu/nu mice developed neither insulitis nor hyperglycemia after the same treatment. In the nu/nu mice, when thymic immunity was restored by thymus grafting, both insulitis and hyperglycemia developed, thus demonstrating that thymic immunity was a prerequisite for the development of insulitis and hyperglycemia. There was a positive correlation among the degrees of thymic immunity, insulitis, and hyperglycemia in CD-1 +/nu, nu/nu with thymus grafts, and nu/nu mice, indicating that thymic immunity may amplify the diabetogenic effect of STZ by eliciting insulitis. In contrast, in BALB/cAJcl mice, a nonsusceptible strain to insulitis, no significant differences in plasma glucose levels were observed between the +/nu and nu/nu or between the nu/nu and thymus-grafted nu/nu mice. Furthermore, no significant difference was found in plasma testosterone levels between the +/nu and nu/nu mice of both CD-1 and BALB/cAJcl origin. In conclusion, our data indicate that thymic immunity enhances the diabetogenic effect of STZ by eliciting insulitis in susceptible mice.

Animals↗
PubMed1982

Mechanism of antibody-mediated protection against herpes simplex virus infection in athymic nude mice: requirement of Fc portion of antibody.

Experiments were performed to investigate the resistance of the host due to antibody-mediated mechanisms to herpes simplex virus (HSV) infection. Transfer of hyperimmune anti-HSV mouse serum inhibited the development of skin lesions and prolonged the survival of lethally HSV-infected nude mice. Relatively high concentrations of antibody were required to achieve this protection. Antisera prepared in heterologous animals were also effective, while administration of anti-cowpox virus serum or interferon provided no protection. This type of protection is therefore due to specific antibody and cannot be attributed to interferon. In order to delineate the requirement for antibody in antibody-mediated protection, human gamma globulin preparations were transferred to lethally HSV-infected nude mice. Transfer of intact human gamma globulin (GG) was effective in controlling infection. S-sulfonation of GG did not diminish the protective ability. However, purified F(ab')2 did not have any protective action even when it was administered frequently to maintain serum neutralizing antibody titer. GG was effective in C5-deficient mice lethally infected with HSV. These results indicate that in vivo antibody-mediated protection to HSV infection requires the Fc region of the intact IgG molecule and suggest that antibody-dependent cell-mediated cytotoxicity may be operative in vivo.

Animals↗
PubMed1982

Production of anti-rat islet cell surface antibody in guinea pigs.

Anti-rat islet serum was prepared in guinea pigs by multiple subcutaneous inoculations of rat islets homogenates emulsified in complete Freund's adjuvant (CFA). The anti-rat islet serum was cytotoxic against rat spleen cells in the presence of complement and the nonspecific antibodies were observed with homogenates of rat livers and spleens. After absorption, the serum lost the cytotoxicity against the rat spleen cells yet showed specific cytotoxicity against the rat islet cells. The binding capacity of anti-rat islet antibody was determined by the indirect immunofluorescence test using FITC conjugated rabbit anti-guinea pig IgG serum. As the guinea pig anti-rat islet serum contained anti-insulin antibody, the role of this antibody in this cytotoxic activity and surface immunofluorescence was studied. However, the anti-insulin antibody used as the control showed neither cytotoxicity nor surface immunofluorescence. After neutralizing the anti-insulin antibody in the antiserum with insulin, the serum remained cytotoxic to the rat islet cells and a surface immunofluorescence appeared. These data show that specific anti-rat islet cell surface antibody can be produced in guinea pigs by multiple inoculations of rat islets homogenates with CFA.

Animals↗
PubMed1979

Production of tubular structures in Vero cells infected with herpes simplex virus type 2; effects of ultraviolet light irradiation and antimetabolites.

In order to investigate the nature of tubular structures specifically found in herpes simplex virus type 2 (HSV-2)-infected cells, the multiplication of HSV-2 was studied in Vero cells cultured in the presence of varying concentrations of cytosine arabinoside (Ara-C) and cycloheximide (CH), inhibitors of DNA synthesis and protein synthesis respectively. Ara-C, at a concentration of 60 micrograms/ml, inhibited the multiplication of HSV-2 by more than 99% and also prevented the appearance of tubular structures and virus particles in the nuclei of infected cells. Nevertheless, the synthesis of virus specific surface antigens of HSV-2-infected Vero cells was not reduced, as revealed by the fluorescent antibody technique. On the other hand, 10 micrograms/ml of CH inhibited both the appearance of tubular structures and virus particles and the synthesis of virus specific surface antigens by more than 99%. These observations strongly suggest that the appearance of tubular structures is one of the late events in the process of virus multiplication. To measure the comparative genome size needed to produce membrane antigens, tubular structures and infectious centres, the effect of u.v.-inactivation of HSV-2 on these processes was studied. After u.v.-irradiation, the capacity to induce tubular structures was inactivated at a slower rate than the capacity to form infectious centres, but at a faster rate than the induction of surface antigens. Furthermore, more tubular structures could be induced by u.v.-inactivated virus than by the non-irradiated virus which was diluted to the same infectivity as the u.v.-irradiated virus. These results indicate that expression of the entire genome is not required for the production of tubular structures.

Animals↗
PubMedDate not supplied

Sex identification of forensic specimens by polymerase chain reaction (PCR): two alternative methods.

Sex identification of forensic samples (bloodstains and decomposed tissue) by polymerase chain reaction (PCR) was investigated. Amplification of a segment of the amelogenin gene using a pair of primers revealed both Y- and X-specific bands at the same time. The gene has counterparts in both the X and Y chromosomes and a small deletion in the former made it possible to distinguish them. Analysis of the X-specific band is the most reliable method for sex identification. THe locus includes a single copy gene so a sample of 250 ng/tube of deoxyribonucleic acid (DNA) is required for identification. Amplification of part of the DYZ1 locus was attempted as an alternative method for analysis of infinitesimal amounts of sample. Even DNA from putrefied tissue could be analyzed by PCR because the locus consists of thousands of copies of repeating units pHY10.

Amelogenin↗
PubMedDate not supplied

Normal Y sequences in Smith-Lemli-Opitz syndrome with total failure of masculinization.

We report an infant with characteristics of Smith-Lemli-Opitz syndrome who had anteverted nostrils, apparently low-set ears, micrognathia, high-arched palate, cleft palate, growth and psychomotor retardation, hypotonia, poor suck, cerebral hypotrophy and double renal pelvis and ureter. An EEG showed spike waves in the right temporal area. The patient appeared to have normal internal and external genitalia of the female type. Both ovaries were dysplastic. The karyotype was 46,XY. All of 26 loci on the Y chromosome were positive including SRY, a candidate gene for TDF.

Abnormalities, Multiple↗