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Biomedical subjects

M Fujihara

Publications and source records attributed to M Fujihara.

At least 73 records · Page 4Linked to original sources
PubMed1994

p53 mutations in lung cancers from Japanese mustard gas workers.

Mustard gas (MG) is a mutagenic and carcinogenic alkylating agent, and is a known risk factor for occupational lung cancer. Our hypothesis is that lung cancers from MG workers contain mutations (G:C to A:T transitions) as the result of MG-produced DNA promutagenic adducts in the p53 tumor suppressor gene. We analyzed 12 primary lung cancers from Japanese MG factory workers and 12 lung cancers from non-exposed individuals. Genomic DNA was isolated from archival paraffin-embedded tissues. Exons 5-8 were amplified by polymerase chain reaction using p53-specific primers, and sequenced by dideoxy termination methods. Six out of 12 lung cancers from MG workers contained a total of eight somatic point mutations: two cases had double G:C to A:T transitions; one had a G:C to T:A transversion; one case had an A:T to G:C transition; and two cases had single base deletions. Four of the six mutated purines occurred on the non-transcribed, DNA-coding strand. Out of 12 unexposed cases, there were six single base mutations in six cancers, and no double mutations. The p53 mutational frequency in the MG-exposed cases is similar to the non-exposed controls and the usual smoking-related lung cancers reported previously. However, the distinctive double mutations (G:C to A:T transition) observed in two cases are unusual and may be related to MG exposure.

Aged↗
PubMed1994

Effects of agars on determination of potency of polymyxin B sulfate by the agar plate diffusion method.

The effects of agars on the determination of the potency of polymyxin B sulfate by the agar plate diffusion method were investigated. The results showed that there were significant differences in the potency of polymyxin B sulfate between agars produced by different manufacturers. In order to investigate this phenomenon, two major components of polymyxin B sulfate, namely, the polymyxin B1 and B2 fractions, were isolated and purified by preparative high-pressure liquid chromatography, and the effects of agars on the potencies of these two components were individually examined. The results showed that there were significant differences in the relative potency of the B1 component versus that of the B2 component between the agar preparations produced by different manufacturers. On the basis of the relative potency of each of the components and the composition of the components, we developed a theoretical equation with which we could calculate the activity of polymyxin B sulfate on a certain agar. The values computed from the equation were consistent with those obtained from actual measurements. It was concluded that the effects of agars on the determination of polymyxin B sulfate activity will become evident only when the composition of the reference standard significantly differs from that of the samples. When the standard and samples have the same compositions, the sources of the agar preparation exert no effect on the determination of the potency by the agar plate diffusion method.

Agar↗
PubMed1994

Inhibition of plasma endothelin-1 concentration by captopril in patients with essential hypertension.

The aim of this study was to determine whether captopril has any effect on plasma endothelin-1 (ET-1) concentration in patients with essential hypertension. Nine normotensives and eleven hypertensives were included in this study. Blood pressure and pulse rate were monitored before and at 60 min after captopril ingestion (25 mg). Simultaneously, blood samples for plasma ET-1 and plasma renin activity (PRA) determination were obtained. In the normotensives, captopril treatment resulted in a significant rise in PRA, but without statistical changes in blood pressure and plasma ET-1. By contrast, in the hypertensives, although PRA elevated similarly after captopril, both blood pressure and plasma ET-1 decreased significantly compared with their respective preloading level. These data suggest that the blood pressure-lowering effect of captopril in essential hypertension may be at least in part, mediated by its inhibition of ET-1 production from the vascular endothelium.

Blood Pressure↗
PubMed1993

Mechanism of lipopolysaccharide-triggered junB activation in a mouse macrophage-like cell line (J774).

The effect of lipopolysaccharide (LPS) on the activation of junB in a mouse macrophage cell line (J774) was investigated. J774 cells responded to either phorbol 12-myristate 13-acetate (PMA) or LPS by the transient increase in the expression levels of c-jun and junB mRNA, but not of junD mRNA. The prior depletion of protein kinase C from J774 cells blocked the action of PMA, but not of LPS, to activate junB. Pretreatment of cells with H-89 or H-7, but not with HA1004, W-7, ML-7, or tyrphostin 47, inhibited LPS-triggered junB activation. Treatment with forskolin also activated junB of J774 cells through an H-89- or H-7-sensitive pathway. Since cAMP-dependent protein kinase activity of J774 cells was inhibited by H-89, but not by H-7, LPS appears to activate junB through a cascade involving two steps, the one sensitive to H-89 and the other to H-7. Western blot analysis showed that LPS-triggered junB activation is accompanied by the increased expression of JunB proteins in the cell lysate as well as in the nuclear extract. JunB in nuclear fraction appears to specifically bind to 12-O-tetradecanoylphorbol-13-acetate-response element (TRE), since preincubation of nuclear extracts with anti-JunB serum reduced the amount of TRE-binding proteins and since the amount of JunB, but not of c-Jun or JunD, immunoprecipitated from TRE-cross-linked nuclear proteins increased in response to LPS. Thus, JunB may play an important role in LPS-triggered gene activation.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1993

Acute effects of oral glucose loading on the renin-angiotensin-aldosterone system in patients with chronic renal disease.

To determine the changes of the glucose-induced renin-angiotensin-aldosterone system in chronic renal disease, a standard oral glucose loading test (75g) was performed in patients with chronic glomerulonephritis (CGN) (n = 12) and compared with control subjects (10). Glucose loading resulted in a significant decrease of serum aldosterone as well as increases of blood glucose and insulin similarly in both CGN and C. However, the suppression of aldosterone was statistically milder in CGN than in C (p < 0.05). In contrast, significant elevations of plasma renin activity were observed in CGN at 60 and 120 min, but not in C after glucose loading. Urinary sodium excretion after glucose ingestion was lower in CGN than in C. These data demonstrated that the glucose-induced renin-angiotensin-aldosterone system in patients with chronic renal disease differed from that in healthy subjects.

Adult↗
PubMed1992

Infection of terminally differentiated myotubes with Rous sarcoma virus (RSV): lack of DNA integration but presence of RSV mRNA.

We re-examined the generally accepted concept that replication of Rous sarcoma virus (RSV) requires host DNA synthesis. We used terminally differentiated chicken myotubes as the host because chromosomal DNA replication is completely abolished by the natural differentiation process. Southern blot analysis detected unintegrated viral DNA in both the nucleus and cytoplasm of infected myotubes. This indicated that reverse transcription of the infecting viral RNA and transport of the newly synthesized viral DNA into the nucleus proceeded normally in myotubes. However, restriction enzyme digestion of high M(r) DNA prepared from infected myotubes produced none of the fragments specific for RSV, indicating that the viral DNA had failed to integrate into the myotube chromosomal DNA. In these infected myotubes, viral RNA was detected by in situ hybridization. Northern blot analysis showed the presence of all three RSV mRNAs (38S, 28S and 21S). The amount of these viral RNAs in infected myotubes was comparable with that found in infected fibroblasts. We conclude that host DNA synthesis is required for RSV integration, but, in contrast to the generally accepted concept, viral DNA integration is not an absolute requirement for transcription of the RSV genome.

Animals↗
PubMed1992

Infection of terminally differentiated myotubes with Rous sarcoma virus: reduced synthesis of env and v-src proteins.

We studied Rous sarcoma virus (RSV) protein synthesis in RSV-infected, terminally differentiated chicken myotubes ('late-infected' myotubes), in which no viral DNA integration takes place but all three viral mRNAs (38S, 28S and 21S) are transcribed normally. With the use of specific anti-RSV protein antisera, we found that only the viral gag and pol proteins were synthesized at levels similar to those synthesized in RSV-transformed fibroblasts; the synthesis of env and v-src proteins was significantly reduced in these infected myotubes. We concluded that the viral RNA transcribed from the unintegrated RSV DNA was functional but that genes at the 3' end of the RSV genome were translated at a lower level. By contrast, when mononucleated replicating chicken myoblasts were infected with a mutant (tsNY68) carrying a temperature-sensitive v-src gene and maintained at the non-permissive temperature for this gene, they developed into myotubes with viral DNA integrated in their chromosomal DNA. These 'early-infected' myotubes expressed all four viral genes (gag, pol, env and v-src) at a level similar to that in infected fibroblasts. This result ruled out the possible presence of specific factor(s) in myotubes that preferentially inhibit the 3' genes of RSV, and suggested other translational control(s) of viral gene expression in late-infected myotubes.

Animals↗
PubMed1990

Lack of tumorigenicity of aminopyrine orally administered to B6C3F1 mice.

To test the tumorigenic potential of aminopyrine, an antipyretic analgesic, it was administered in drinking water at levels of 0 (control), 0.04 and 0.08% to 50 male and 50 female B6C3F1 mice for 100 weeks, and the mice were subsequently maintained without aminopyrine for a further 4 weeks. The most frequent types of tumor, in both treated and control groups, were hepatocellular tumor in male mice and malignant lymphoma/lymphoid leukemia in female mice. No statistically significant differences were observed in the incidences of these tumors between treated and control groups. The incidences of several other tumors in male and female mice also showed no statistically significant differences between treated and control groups. Therefore, no tumorigenic effect of orally administered aminopyrine in B6C3F1 mice was apparent in the present study.

Administration, Oral↗
PubMed1990

Anti-Kveim monoclonal antibody. New monoclonal antibody reacting to epithelioid cells in sarcoid granulomas.

A monoclonal antibody to the sarcoid granulomagenic agent contained in Kveim suspension was prepared by immunizing mice with Kveim suspension. One monoclonal antibody (IHY-1) that reacted with the epithelioid cells in sarcoid granulomas on immunoperoxidase technique was selected. The immunoperoxidase technique was used to compare this monoclonal antibody's binding to sarcoidosis- or tuberculosis-affected lymph nodes. IHY-1 is a monoclonal antibody of IgM class. This antibody did not react to erythrocytes, lymphocytes, monocytes, alveolar macrophages, or the macrophage-derived cell lines such as U-973 and KG-1. It reacted to granuloma epithelioid cells of sarcoidosis-affected lymph nodes. The monoclonal antibody also reacted positively to epithelioid cells in tuberculous granulomas although the reaction was not as strong. Since IHY-1 was found to bind to both types of granulomas, this suggests that the epithelioid cells in sarcoidosis have antigenicity common to the epithelioid cells in tuberculosis.

Animals↗
PubMed1989

Isolation, purification, and characterization of fucose-containing sulfated polysaccharides from the brown seaweed Ecklonia kurome and their blood-anticoagulant activities.

A sulfated polysaccharide fraction, obtained from the hot-water extract of the brown seaweed, Ecklonia kurome by removing laminaran and the major part of alginic acid, gave sulfated polysaccharides (B-I, B-II, C-I, and C-II) by both anion-exchange chromatography on a column of Ecteola-cellulose and by fractional precipitation with ethanol containing 0.3% calcium acetate, and then by gel-filtration chromatography on a Sepharose 4B column. B-I and B-II are composed of fucose, galactose, mannose, xylose, glucuronic acid, and ester sulfate in the approximate molar ratios of 1.00:0.36:0.48:1.08:1.85:2.35 and 1.00:0.81:0.18:0.45:0.61:2.00, respectively. C-I and C-II are composed of fucose, galactose, glucuronic acid, and ester sulfate in approximate molar ratios of 1.00:0.03:0.03:1.61 and 1.00:0.19:0.07:1.48, respectively. Blood-anticoagulant activities with respect to activated partial thromboplastin time (APTT) were approximately 24, 19, 81, and 85% of that of heparin for B-I, B-II, C-I, and C-II, respectively. All the polysaccharides showed slight antithrombin activity. No antifactor Xa activity was observed for any of the polysaccharides.

Animals↗
PubMed1989

Effect of 2',5'-oligoadenylate on herpes simplex virus-infected cells and preventive action of 2',5'-oligoadenylate on the lethal effect of HSV-2.

Antiviral effects of ppp(A2'p)nA, (2-5A) on herpes simplex virus type 1 or type 2 (HSV-1 or HSV-2)-infected baby hamster kidney fibroblasts (BHK cells) and HSV-2-infected female guinea pigs were examined. 2-5A was introduced into BHK cells in the form of a calcium phosphate precipitate and as an ointment of polyethylene glycol (PEG) into guinea pig vagina. Under optimum conditions, 2-5A trimer and other 2-5A derivatives inhibited over 90% of HSV-1 syncytia formation and over 50% of HSV-2 plaque formation. The growth of uninfected cells was only slightly and transiently inhibited under these conditions. Northern analysis of viral immediate early mRNAs and cellular mRNAs showed that all transcripts determined were reduced in amount by the 2-5A trimer treatment. The reduction in level of viral mRNAs (ICP4, ICP22, and ICP47) by 2-5A trimer was significantly more than that of cellular mRNAs (represented by beta-actin). HSV-2 (strain 186) inoculation into the vagina of female guinea pigs causes severe symptoms in the genital area and high mortality. Topically applied 2-5A trimer almost completely prevented the lethal effect of HSV-2. These data are discussed from the viewpoint of mechanism of interferon action.

Adenine Nucleotides↗
PubMed1989

Diabetic state-induced activation of calcium-activated neutral proteinase in mouse skeletal muscle.

The effect of a diabetic state in the diabetic KK-CAy mouse on calcium activated neutral proteinase (CANP) of hind-limb skeletal muscles was investigated. In the diabetic state, there was an increased sensitivity to activation of CANP by calcium (Ca). In addition, there was an enhancement of maximal activity of the enzyme. The effect was induced by secondary modification of the diabetic state, but not genetical factors. Several lines of evidence suggest that the CANP is responsible for 92 K dalton protein in diabetic skeletal muscles. Among the evidence are the following: a) The 92 K band in the diabetic muscles was lower than in the prediabetic mouse and restored by the addition of 2 mM EDTA and 2 mM EGTA. b) The band was reduced by increasing the Ca content and neutral pH in the non-diabetic normal muscles. c) E-64-C, a CANP inhibitor, restored the 92 K component reduced by the diabetic state. Since the band in denervated muscles was not changed by the Ca chelating agents, the reduction of the band in the diabetic muscles is related with musculotrophic factors, not diabetic neuropathy. These results suggest that diabetic amyotrophy may be regarded as a phenomenon linked to an increase in intracellular Ca ions and an increase in CANP activity.

Actinin↗
PubMed1988

Diabetic state-induced modifications of succinylcholine binding mode in the microsomal fractions of mouse skeletal muscles.

The skeletal muscles of alloxan-induced diabetic mice and genetically diabetic KK-CAY mice are hypersensitive to a depolarizing blocker, succinylcholine (SuCh) but not to the competitive antagonist, d-tubocurarine (d-TC). The mechanism by which the action of the depolarizing blocker is modified in the diabetic state was investigated on the binding of 14C-SuCh to the microsomal fraction isolated from mouse skeletal muscles. The Scatchard plot of microsomal preparations from normal ddY mice showed positive cooperativity in SuCh binding, whereas that of the preparations from alloxan-induced diabetic mice as well as genetically diabetic KK-CAY mice lost the positive cooperative interactions. The dissociation constant (Kd) of high affinity site in diabetic muscles was significantly lower than that in non-diabetic ddY muscle. The microsomal fractions from denervated muscles of normal ddY mice maintained weakly positive cooperativity in SuCh binding, and the affinity of SuCh binding in denervated muscles was lower than that of non-denervated muscles. In conclusion, the diabetic state selectively altered the SuCh binding mode. This alteration seems to be closely correlated with the pharmacological hypersensitivity to SuCh.

Alloxan↗
PubMed1988

Hepatocellular tumorigenicity of butylated hydroxytoluene administered orally to B6C3F1 mice.

Butylated hydroxytoluene (BHT), a preservative widely found in food as a food additive, was orally administered at concentrations of 1% and 2% of the diet to B6C3F1 mice for 104 consecutive weeks. Treated animals underwent a 16-week recovery period prior to pathological examination. In male mice administered BHT, the incidence of mice with either a hepatocellular adenoma or a focus of cellular alteration in the liver was increased in a clear dose-response relationship. The incidences of male mice with other tumors and the incidences of female mice with any tumor were not significantly increased as a consequence of BHT administration. The results of this study indicate BHT to be tumorigenic to the liver of the B6C3F1 male mouse.

Administration, Oral↗