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Biomedical subjects

M Yamaguchi

Publications and source records attributed to M Yamaguchi.

At least 1,441 records · Page 80Linked to original sources
PubMed1988

[Clinical effect of prostaglandin E1 on liver dysfunction due to high-dose methotrexate].

The effect of prostaglandin E1 (PGE1) on liver dysfunction due to high-dose methotrexate (HD-MTX) was investigated in children with malignant diseases. Eight children received 45 doses of HD-MTX. Group 1 (33 cases) received no PGE1. Group 2 (4 cases) received PGE1 intravenously 8 times every 12 hours for 3 consecutive days. Group 3 (8 cases) received infusion of PGE1 continuously for 4 days (1 day before and 3 consecutive days after MTX infusion). No significant difference was observed among the serum levels of transaminase in these 3 groups as well as the corresponding levels in the same patients who were treated with or without PGE1. There are reports suggesting that in spite of the lack of any difference in serum transaminase levels in rats with drug-induced hepatic injury given PGE1 infusion, data on DNA synthesis and survival ratio indicate the existence of 'hepatocytoprotection'. Further investigation will be necessary in order to decide whether PGE1 infusion is indeed effective.

Alprostadil↗
PubMed1987

Western-blotting method for detecting antibodies against human muscle contractile proteins in myositis.

Many investigators report anti-muscle antibodies using various kinds of methods. The Western-blotting method, however, has not previously been used for this purpose. We have detected antibodies to muscle contractile proteins in sera from patients with collagen disease and muscular dystrophy by this method. The antigens detected included myosin heavy and light chains, tropomyosin and troponin complex. Our method is a quick and sensitive way to determine which are the antigenic muscle contractile proteins.

Actins↗
PubMed1987

Stimulatory effect of zinc on bone formation in tissue culture.

The present investigation was undertaken to clarify the in vitro effect of zinc on bone metabolism in tissue culture. Calvaria were removed from weanling rats (3-week-old males) and cultured for periods up to 96 hr in Dulbecco's Modified Eagle Medium (high glucose, 4500 mg/dl) supplemented with antibiotics and bovine serum albumin. The experimental cultures contained 10(-7) to 10(-3) M zinc sulfate. All cultures were incubated at 37 degrees in 5% CO2/95% air. Zinc uptake by bone was increased significantly in cultures with concentrations of zinc greater than 10(-6) M. Bone calcium content was increased significantly by the presence of 10(-4) M zinc. This increase was blocked by the presence of 10(-6) M cycloheximide. Bone alkaline phosphatase activity was elevated in the presence of zinc (10(-6) to 10(-3) M), but the effect was inhibited by 10(-7) M cycloheximide or 10(-8) M actinomycin D. Zinc (10(-4) M) also significantly increased ATPase activity in the bone, whereas it did not alter significantly by pyrophosphatase, acid phosphatase and beta-N-acetylglucosaminidase activities. Furthermore, bone collagen content was raised by 10(-6) to 10(-4) M zinc. This elevation was prevented by 10(-7) cycloheximide or 10(-8) M actinomycin D. Bone DNA content and [3H]thymidine incorporation by the bone were not altered significantly by 10(-4) M zinc. These findings indicate that the zinc had a direct stimulatory effect on bone mineralization in vitro, and that bone protein synthesis was a necessary component of this response. Zinc may stimulate bone formation in tissue culture.

Alkaline Phosphatase↗
PubMed1987

Highly sensitive and simple determination of cholesterol and cholestanol in human serum by high-performance liquid chromatography with fluorescence detection.

A simple and highly sensitive high-performance liquid chromatographic method for the determination of cholesterol and cholestanol in human serum is described. After extraction of serum with n-hexane, these compounds and 1-eicosanol (internal standard) are converted into the corresponding fluorescent carbamic esters by treatment with 3,4-dihydro-6,7-dimethoxy-4-methyl-3-oxo-quinoxaline-2-carbonyl azide in benzene. The derivatives are separated within 32 min on a reversed-phase column (YMC Pack C8) with acetonitrile-methanol-water (81:9:10, v/v/v) as eluent and detected fluorimetrically. The detection limits are 2 pg (5 fmol) and 3 pg (7 fmol) for cholesterol and cholestanol, respectively, at a signal-to-noise ratio of 2 in a 20-microliters injection volume. This sensitivity permits precise determination of cholesterol and cholestanol in 1-5 microliters of normal human serum.

Cholestanols↗
PubMed1987

In vitro initiation of DNA replication in simian virus 40 chromosomes.

A soluble system has been developed that can initiate DNA replication de novo in simian virus 40 (SV40) chromatin isolated from virus-infected monkey cells as well as in circular plasmid DNA containing a functional SV40 origin of replication (ori). Initiation of DNA replication in SV40 chromatin required the soluble fraction from a high-salt nuclear extract of SV40-infected cells, a low-salt cytosol fraction, polyethylene glycol, and a buffered salts solution containing all four standard deoxyribonucleoside triphosphates. Purified SV40 large tumor antigen (T-ag) partially substituted for the high-salt nucleosol, and monoclonal antibodies directed against SV40 T-ag inhibited DNA replication. Replication began at ori and proceeded bidirectionally to generate replicating DNA intermediates in which the parental strands remained covalently closed, as observed in vivo. Partial inhibition of DNA synthesis by aphidicolin resulted in accumulation of newly initiated replicating intermediates in this system, a phenomenon not observed under conditions that supported completion of replication only. However, conditions that were optimal for initiation of replication repressed conversion of late-replicating intermediates into circular DNA monomers. Most surprising was the observation that p-n-butylphenyl-dGTP, a potent and specific inhibitor of DNA polymerase-alpha, failed to inhibit replication of SV40 chromatin under conditions that completely inhibited replication of plasmid DNA containing the SV40 ori and either purified or endogenous DNA polymerase-alpha activity. In contrast, all of these DNA synthesis activities were inhibited equally by aphidicolin. Therefore, DNA replication in mammalian cells is carried out either by DNA polymerase-alpha that bears a unique association with chromatin or by a different enzyme such as DNA polymerase-delta.

Antigens, Neoplasm↗
PubMed1987

[TRH and cyclo (His-Pro) concentrations in the young rat brain are altered by a liquid protein diet].

Effects of liquid protein diet (LPD), that is known to be poor in protein quality, on brain TRH and cyclo (His-Pro) concentrations were explored in young male rats. At day 23 of weaning, the animals were fed either a 20% casein diet ad libitum or a 20% LPD, or were pair-fed with a 20% casein diet. They were decapitated at day 35 or day 48. The body weight of those in the LPD group decreased significantly, and the loss was sustained in comparison with those in the pair-fed and ad libitum groups. The extrahypothalamic cyclo (His-Pro) concentrations were significantly greater in the LPD group than in the pair-fed and ad libitum groups throughout the experimental period, whereas these concentrations were similar in the pair-fed and ad libitum groups. At day 48, TRH concentrations in the hypothalamus and extrahypothalamus also increased in the LPD group in comparison with the concentrations in ad libitum group. These data indicate that quality of the protein component in the diet has a potential effect on alteration in the neuropeptides, TRH and cyclo (His-Pro), in the young rat brain.

Animals↗
PubMed1987

Homology between mammalian DNA polymerase beta and terminal deoxynucleotidyltransferase.

Nucleotide sequence analysis of the cDNA and the genomic clones for rat DNA polymerase beta revealed the existence of a 1,005-base pair open reading frame capable of encoding a Mr = 38,269 polypeptide of 335 amino acid residues. The region of 174 amino acid residues between the 42nd and 215th residues of the DNA polymerase beta polypeptide has extensive amino acid sequence homology with the region between the 195th and 366th residues of human terminal deoxynucleotidyltransferase. The two enzymes share extensive homology not only in primary structures but also in the computer-derived higher structures in these particular regions. The genes for DNA polymerase beta and terminal deoxynucleotidyltransferase are proposed to be derived from a common ancestral DNA polymerase gene.

Amino Acid Sequence↗
PubMed1987

c-myc protein can be substituted for SV40 T antigen in SV40 DNA replication.

Replicating activity of SV40 origin-containing plasmid was tested in human cells as well as in monkey CosI cells. All the plasmids possessing SV40 ori sequences could replicate, even in the absence of SV40 T antigen, in human HL-60 and Raji cells which are expressing c-myc gene at high level. The copy numbers of the replicated plasmids in these human cells were 1/100 as high as in monkey CosI cells which express SV40 T antigen constitutively. Exactly the same plasmids as the transfected original ones were recovered from the Hirt supernatant of the transfected HL-60 cells. Furthermore, replication of the SV40 ori-containing plasmids in HL-60 cells was inhibited by anti-c-myc antibody co-transfected into the cells. These results indicate that the c-myc protein can be substituted for SV40 T antigen in SV40 DNA replication.

Animals↗
PubMed1987

Determination of free and total phenylacetic and p- and m-hydroxyphenylacetic acids in human urine by liquid chromatography with fluorimetric detection.

A highly sensitive and rapid liquid chromatographic method for the determination of free and total phenylacetic and p- and m-hydroxyphenylacetic acids in human urine is described. After extraction of urine with diethyl ether, these acids and phenylpropionic acid (internal standard) are converted into the corresponding fluorescent derivatives by treatment with 3-bromomethyl-6,7-dimethoxy-1-methyl-2(1H)-quinoxalinone in the presence of potassium hydrogen carbonate and 18-crown-6 in acetonitrile. The derivatives are separated on a reversed-phase column (Radial-Pak cartridge C18) with aqueous 65% (v/v) methanol and detected fluorimetrically. The detection limits for phenylacetic and p- and m-hydroxyphenylacetic acids are 5, 30 and 100 fmol, respectively, at a signal-to-noise ratio of 5 in a 20-microliter injection volume. This sensitivity permits precise determination of the free and total acids in 20 microliter of normal human urine.

Adult↗
PubMed1987

Ultrasonic evaluation of pediatric superficial masses.

Mechanical sector scanning using a balloon and electronic scanning using transrectal probes were applied in the diagnosis of pediatric superficial masses. In 135 cases of pediatric superficial masses definitely diagnosed by surgical findings and histopathologic examinations, a comparative investigation was performed between the surgical and histopathologic findings and ultrasonographic findings. Among these 135 cases, 117 of the masses were benign, and 18 were malignant. By means of these scans, it was possible to diagnose correctly not only the size and shape of the mass but also the internal characteristics. However, it was difficult to determine if the mass was benign or malignant.

Child↗
PubMed1987

A new experimental animal for the study of age-related changes in serotonergic neuronal activity in the brain cortex.

Calcium uptake by the cortical synaptosomes in a rodent (Fischer rat) and an insectivore shrew (Suncus murinus) was detected as a parameter reflecting molecular dysfunction of the aging brain. The change in calcium uptake by the cortical synaptosomes in both species was concomitant which showed less than half the capacity at 24 months old animals compared with those at 8 months old. On the other hand, 5-hydroxytryptamine binding and imipramine binding to the membrane fraction of aging rat brain cortex was not altered in terms of binding capacity along with aging, while, in Suncus, the binding of both serotonergic ligands declined with aging. In order to elucidate decreased serotonergic activity in human demented aged brain, together with declining activity in neurotransmitting systems detectable as a function of calcium uptake by the cortical synaptosomes, Suncus may be an appropriate animal model for studying physiological aging processes in the mammalian brain cortex.

Aging↗
PubMed1987

Preventive effect of zinc for toxic actions of germanium and selenium on bone metabolism in weanling rats.

The preventive effect of zinc for the toxic actions of germanium and selenium on bone metabolism was investigated in the femoral diaphysis of weanling rats. Germanium tetrachloride (1.53-30.60 mumol Ge/100 g b.w.) and selenium tetrachloride (1.53-7.65 mumol Se/100 g) was administered orally for 3 days. The doses of 1.53 and 7.65 mumol Ge/100 g caused a significant increase in DNA content although alkaline phosphatase activity was not altered significantly. By the dose of 30.60 mumol Ge/100 g, both alkaline phosphatase activity and DNA content were decreased significantly. Administration of selenium (1.53 and 7.65 mumol/100 g) produced significantly decreases in alkaline phosphatase activity and DNA content. The decreases of the enzyme activity and DNA content caused by administration of germanium (30.60 mumol/100 g) and selenium (7.65 mumol/100 g) were prevented completely by simultaneous injection of zinc sulfate (7.65 mumol Zn/100 g) for 3 days. Administration of zinc also produced appreciable increase in alkaline phosphatase activity and DNA content. The present study indicates that germanium and selenium disturbs bone metabolism in weanling rats, and that this disturbance is reversed by zinc.

Alkaline Phosphatase↗
PubMed1987

Antitumor effects of recombinant human tumor necrosis factor against human tumor xenografts transplanted into nude mice.

Antitumor activities of recombinant human tumor necrosis factor (rH-TNF) against human tumor xenografts in nude mice were studied. Thirteen human tumor xenografts serially transplanted into nude mice were used for experiments; five gastric, two breast, two gallbladder, one colon and one esophageal carcinoma, one liposarcoma and one squamous carcinoma of the neck. They were inoculated into the subcutaneous tissue of BALB/c nu/nu nude mice and the treatment was started when the estimated tumor weight reached 100-300 mg. rH-TNF was administered intratumorally at schedule of qd X 5 or q3d X 5. rH-TNF showed a marked antitumor activity against various human tumors. The hemorrhagic necrosis was observed in all types of the human tumor xenografts (100 per cent), and the complete regression of the tumor was noted in 4 of 11 tumors (36.4 per cent). On the contrary, intraperitoneal rH-TNF exhibited little antitumor effect. The additive effect in the combination of TNF and Mitomycin C was observed against two Mitomycin C resistant gastric tumors.

Animals↗
PubMed1987

Effect of oxygen tension on the antitumor activity of mitomycin C assayed by human tumor clonogenic assay.

The effects of oxygen tensions on the antitumor activity of mitomycin-C (MMC) were surveyed using the human tumor clonogenic assay technique. Six human tumor xenografts (4 gastric cancers, and 2 colon cancers) were used in this study. Tumor cells were continuously exposed to MMC during the experimental period at various oxygen tensions, such as 2 per cent, which is considered to be hypoxic oxygen tension, 5 per cent which is considered as the physiological oxygen tension, and 20 per cent which is the conventional in vitro culture condition. The antitumor activities of MMC on the 6 human tumor xenografts increased when the oxygen tension was lowered from 20 per cent to 5 per cent. However, no further increases of the antitumor activities of MMC were observed by lowering the oxygen tension from 5 to 2 per cent. Additionally, the in vitro antitumor activities of MMC at various oxygen tensions were compared with the in vivo chemosensitivities evaluated in nude mice. In five of the 6 human tumor xenografts, in vitro chemosensitivities assayed at 2 or 5 per cent oxygen tension were concordant with in vivo chemosensitivities, although in vitro chemosensitivities assayed at 20 per cent were concordant with in vivo chemosensitivities in 3 of the 6 tested tumors.

Animals↗
PubMed1987

Comparative study on nude mice isotope assay (NM-IA) and subrenal capsule assay (SRCA) sensitivity tests of anticancer agents.

A comparative study on nude mice isotope assay (NM-IA) and subrenal capsule assay (SRCA) was done to evaluate the usefulness of in vivo assays for predicting individual tumor sensitivity against anticancer agents. Sixty-one fresh tumor specimens collected at surgery, under sterile conditions, were examined. Mitomycin C (MMC), 5-fluorouracil (5-FU), cyclophosphamide (CPM), adriamycin (ADM) and cis-DDPlatinum (CDDP) were used in both assays. In NM-IA, the tumor sensitivity was determined by the amount of 3H-thymidine incorporated into the tumor which had been implanted into subcutaneous spaces of BALB/c nude mice. In the SRCA, the relative increase in weight of the tumor implanted into the subrenal capsular space of ddY mice was determined and measurements made to evaluate the chemosensitivity. Evaluability rates of the trials were 86.9 per cent with both assays and the response rates were 35.8 per cent in NM-IA and 34.0 per cent in SRCA, respectively. Against MMC, 5-FU, CPM, ADM and CDDP, overall consistency rates between the two assays were 77.8 per cent, 88.6 per cent, 72.7 per cent, 81.8 per cent and 68.2 per cent, respectively. In 8 of these 53 evaluated assays, correlations between the results of assays and clinical effects were examined and overall predictive accuracy rates were 87.5 per cent with both assays. Significant differences between these two in vivo chemosensitivity tests were not evident.

Animals↗
PubMed1987

Comparative studies on in vitro human tumor clonogenic assay (HTCA) and in vivo nude mouse-isotope assay (NM-IA).

Comparative studies between the in vitro human tumor clonogenic assay (HTCA) and nude mouse-isotope assay (NM-IA), in which the final evaluation was made with 3H-thymidine incorporations of tumor cells transplanted into nude mice, were performed simultaneously on 60 fresh human tumors. Tissues used included 27 gastric cancers, 10 breast cancers, 7 colorectal cancers, 4 gallbladder cancers, 4 sarcomas, 3 lymphomas, and 5 other tumors. Mitomycin C (MMC), 5-fluorouracil (5-FU), cyclophosphamide (CPM) and adriamycin (ADM) were tested. The overall evaluable rate was 66.7 per cent in HTCA and 83.3 per cent in NM-IA, respectively. When the per cent survival in HTCA and the per cent inhibition in NM-IA less than 50 per cent was defined as drug sensitive, the drug sensitive rates of MMC, 5-FU, CPM, and ADM were 23.1, 16.7, 11.8, and 27.8 per cent in HTCA and 17.6, 18.4, 22.4, and 25.5 per cent in NM-IA, respectively. Although statistically significant correlations between the results of HTCA and those of NM-IA were obtained for MMC and ADM, no correlation was observed for 5-FU and CPM. The overall predictive accuracy rate of clinical response was 83.3 per cent (true positive rate 50 per cent and true negative rate 92.9 per cent) in HTCA and 76.0 per cent (true positive rate 37.5 per cent and true negative rate 93.8 per cent) in NM-IA, respectively.

Animals↗