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Biomedical subjects

K Tsuji

Publications and source records attributed to K Tsuji.

At least 505 records · Page 28Linked to original sources
PubMed1990

Electrooptical studies on proton-binding and -release of bacteriorhodopsin.

Electric field induced pH changes of purple membrane suspensions were investigated in the pH range from 4.1 to 7.6 by measuring the absorbance change of pH indicators. In connection with the photocycle and proton pump ability, three different states of bacteriorhodopsin were used: (1) the native purple bacteriorhodopsin (magnesium and calcium ions are bound, the M intermediate exists in the photocycle and protons are pumped), (2) the cation-depleted blue bacteriorhodopsin (no M intermediate), and (3) the regenerated purple bacteriorhodopsin which is produced either by raising the pH or by adding magnesium ions (the M intermediate exists). In the native purple bacteriorhodopsin there are, at least, two types of proton binding sites: one releases protons and the other takes up protons in the presence of the electric field. On the other hand, blue bacteriorhodopsin and the regenerated purple bacteriorhodopsin (pH increase) show neither proton release nor proton uptake. When magnesium ions are added to the suspensions, the field-induced pH change is observed again. Thus, the stability of proton binding depends strongly on the state of bacteriorhodopsin and differences in proton binding are likely to be related to differences in proton pump activity. Furthermore, it is suggested that the appearance of the M intermediate and proton pumping are not necessarily related.

Bacteriorhodopsins↗
PubMed1990

N-2 acetylation of 2'-deoxyguanosine by coffee mutagens, methylglyoxal and hydrogen peroxide.

Coffee shows direct-acting mutagenicity in Salmonella typhimurium TA100 and most of this mutagenicity is due to the synergistic effects of methylglyoxal and hydrogen peroxide. The modifications of deoxyribonucleosides by methylglyoxal plus hydrogen peroxide were studied in vitro. When 2'-deoxyguanosine (6.25 mumole) was treated with methylglyoxal (125 mumole) and hydrogen peroxide (125 mumole) in 5 ml of 0.1 M phosphate buffer (pH 7.4) at 37 degrees C for 3 h, N2-acetyl-2'-deoxyguanosine was formed with a yield of 1.1%. Its formation increased time-dependently. By contrast, no appreciable modification of other deoxynucleosides was detected after their incubation with methylglyoxal and hydrogen peroxide under similar conditions. N2-Acetyl-2'-deoxyguanosine was also formed during incubation of 2'-deoxyguanosine with instant coffee.

Acetylation↗
PubMed1990

A simple and rapid method for HLA-DP genotyping by digestion of PCR-amplified DNA with allele-specific restriction endonucleases.

We previously reported a simple and rapid method for HLA-DQA genotyping by digestion of polymerase chain reaction-amplified DQA genes with allele-specific restriction endonucleases. Here we report the application of this method to DP genotyping. The second exon of the HLA-DPB genes was selectively amplified from genomic DNAs of 72 HLA-D homozygous B-cell lines by the polymerase chain reaction method. Amplified DNAs were digested with ApaI, SacI, BstUI, FokI, and RsaI, which can recognize allelic sequence variations in the polymorphic segments of the DPB second exon and then subjected to electrophoresis in polyacrylamide gels. Sixteen different polymorphic patterns of the restriction fragments were found, and twelve were identical to patterns predicted from the known DNA sequences correlating with each HLA-DPw specificity defined by cellular typing. The other four patterns were distinct from those of the known DPw specificities, suggesting the presence of novel DP alleles. This polymerase chain reaction-restriction fragment length polymorphism method provides a simple and rapid technique for accurate definition of HLA-DP types at the nucleotide level, replacing the technically demanding method of primed lymphocyte typing.

Alleles↗
PubMed1990

Pathogenesis of fever of unknown origin in patients with acute leukemia and granulocytopenia.

Interleukin-1 (IL-1) is an endogenous pyrogen produced by blood monocytes or tissue macrophages in response to infection. Since hepatic macrophages (Kupffer cells) make up more than 90% of tissue macrophages and have a possibility of remaining intact after cytotoxic chemotherapy, they may be the major producers of IL-1 in infection during prolonged periods of severe monocytopenia in leukemic patients having modern chemotherapy treatment. Hence, the majority of febrile episodes probably due to infection in patients with acute leukemia and granulocytopenia may be caused by an inflammatory response mediated by IL-1 derived from the Kupffer cells in the liver sinuses.

Agranulocytosis↗
PubMed1990

Importance of DQB as an indicator in living-related kidney transplant.

Southern blot hybridization was performed in 16 pairs of living-related kidney transplant patients and donors, using DNA samples extracted from peripheral blood lymphocytes. The number of HLA-DNA-mismatched bands was used as an indicator for graft survival. The total number of DNA-mismatched bands seemed to be a valuable parameter. This was further analyzed and it was found that DQB in particular could be used to predict graft survival. Especially, usefulness of HLA-DNA typing was found in positive MLR, where good prognosis was strongly related to DQB matching. This method can therefore be applied in selecting a suitable living-related donor with the best chance of graft survival.

DNA↗
PubMed1990

16S ribosomal RNA sequence analysis for determination of phylogenetic relationship among methylotrophs.

16S ribosomal RNAs (rRNA) of 12 methylotrophic bacteria have been almost completely sequenced to establish their phylogenetic relationships. Methylotrophs that are physiologically related are phylogenetically diverse and are scattered among the purple eubacteria (class Proteobacteria). Group I methylotrophs can be classified in the beta- and the gamma-subdivisions and group II methylotrophs in the alpha-subdivision of the purple eubacteria, respectively. Pink-pigmented facultative and non-pigmented obligate group II methylotrophs form two distinctly separate branches within the alpha-subdivision. The secondary structures of the 16S rRNA sequences of 'Methylocystis parvus' strain OBBP, 'Methylosinus trichosporium' strain OB3b, 'Methylosporovibrio methanica' strain 81Z and Hyphomicrobium sp. strain DM2 are similar, and these non-pigmented obligate group II methylotrophs form one tight cluster in the alpha-subdivision. The pink-pigmented facultative methylotrophs, Methylobacterium extorquens strain AM1, Methylobacterium sp. strain DM4 and Methylobacterium organophilum strain XX form another cluster within the alpha-subdivision. Although similar in phenotypic characteristics, Methylobacterium organophilum strain XX and Methylobacterium extorquens strain AM1 are clearly distinguishable by their 16S rRNA sequences. The group I methylotrophs, Methylophilus methylotrophus strain AS1 and methylotrophic species DM11, which do not utilize methane, are similar in 16S rRNA sequence to bacteria in the beta-subdivision. The methane-utilizing, obligate group I methanotrophs, Methylococcus capsulatus strain BATH and Methylomonas methanica, are placed in the gamma-subdivision. The results demonstrate that it is possible to distinguish and classify the methylotrophic bacteria using 16S rRNA sequence analysis.

Base Sequence↗
PubMed1990

Pathogenesis of Vibrio parahaemolyticus: intraperitoneal and orogastric challenge experiments in mice.

It has been noted that V. parahaemolyticus isolated from patients with food poisoning are almost always thermostable direct hemolysin (TDH)-positive, whereas, isolates from foods or environmental sources are usually TDH-negative. The virulence of V. parahaemolyticus in mice was examined by using intraperitoneal and orogastric challenge models, where the strains used were those isolated from patients and foods with food poisoning and included TDH-positive and -negative. The LD50 in mice was estimated to be approximately 10(7) in the former and 10(8) in the latter challenge model. In the mice killed by challenge, either intraperitoneal or orogastric, the following pathological changes were almost always observed: swelling, redness and fluid accumulation in the small intestine, particularly the upper part of it. Histologically, congestion, edema, and vacuolation were observed in mucosal and submucosal tissues; furthermore, ulceration at tips of some villi was noticed. The lethality and pathological finding in mice due to V. parahaemolyticus were demonstrated similarly in both challenge models and irrespective of the TDH phenotype of the strain used. It will be suggested that the findings in challenged mice may be attributed to enteropathogenic factor(s) other than TDH of V. parahaemolyticus.

Animals↗
PubMed1990

A simple and rapid method for HLA-DRB and -DQB typing by digestion of PCR-amplified DNA with allele specific restriction endonucleases.

The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method, which we previously reported as an efficient and convenient typing technique for accurate definition of the HLA-DQA1 and -DPB1 alleles, is now extended and applied to HLA-DRB and -DQB typing. The second exon of the HLA-DRB (B1 and B3 or B4) and DQB (B1 and B2) genes was selectively amplified from genomic DNAs of 70 HLA-homozygous B cell lines by PCR. Amplified DNAs were digested with the restriction endonucleases, which can recognize allelic variations specific for HLA-DR, -DQ, and -Dw allospecificities and then subjected to electrophoresis in polyacrylamide gel. Of DRB genes, FokI, HinfI, HhaI, HphI, KpnI and SacII were selected and the 20 different polymorphic patterns of the restriction fragments thus obtained were found to correlate with each HLA-DR and -Dw type defined by serological and cellular typing. Of the DQB genes, FokI, HaeIII, HhaI, RsaI and Sau3AI produced nine different polymorphic patterns of the restriction fragments, correlating with the HLA-DQ and -Dw types. This PCR-RFLP method provides a simple and rapid technique for accurate definition of the HLA-DR, -DQ and -Dw types at the nucleotide level, eliminating the need for radioisotope as well as allele specific oligonucleotide probes.

Alleles↗
PubMed1990

Neurotoxins distinguish between different neuronal nicotinic acetylcholine receptor subunit combinations.

Neuronal and muscle nicotinic acetylcholine receptor subunit combinations expressed in Xenopus oocytes were tested for sensitivity to various neurotoxins. Extensive blockade of the alpha 3 beta 2 neuronal subunit combination was achieved by 10 nM neuronal bungarotoxin. Partial blockade of the alpha 4 beta 2 neuronal and alpha 1 beta 1 gamma delta muscle subunit combinations was caused by 1,000 nM neuronal bungarotoxin. The alpha 2 beta 2 neuronal subunit combination was insensitive to 1,000 nM neuronal bungarotoxin. Nearly complete blockade of all neuronal subunit combinations resulted from incubation with 2 nM neosurugatoxin, whereas 200 nM neosurugatoxin was required for partial blockade of the alpha 1 beta 1 gamma delta muscle subunit combination. The alpha 2 beta 2 and alpha 3 beta 2 neuronal subunit combinations were partially blocked by 10,000 nM lophotoxin analog-1, whereas complete blockade of the alpha 4 beta 2 neuronal and alpha 1 beta 1 gamma delta muscle subunit combinations resulted from incubation with this concentration of lophotoxin analog-1. The alpha 1 beta 1 gamma delta muscle subunit combination was blocked by the alpha-conotoxins G1A and M1 at concentrations of 100 nM. All of the neuronal subunit combinations were insensitive to 10,000 nM of both alpha-conotoxins. Thus, neosurugatoxin and the alpha-conotoxins distinguish between muscle and neuronal subunit combinations, whereas neuronal bungarotoxin and lophotoxin analog-1 distinguish between different neuronal subunit combinations on the basis of differing alpha subunits.

Animals↗
PubMed1990

Biodegradation of low-molecular-weight halogenated hydrocarbons by methanotrophic bacteria.

Low-molecular-weight halogenated hydrocarbons are susceptible to degradation by anaerobic and aerobic bacteria. The methanotrophic bacterium Methylosinus trichosporium 0B3b degrades trichloroethylene more rapidly than other bacteria examined to date. Expression of soluble methane monooxygenase (MMO) is correlated with high rates of biodegradation. An analysis of 16 S rRNA sequences of 11 ribosomal RNAs from type I, type II and type X methanotrophs and methanol-utilizing bacteria have revealed four clusters of phylogenetically related methylotrophs. This information may be useful for the identification and enumeration of methylotrophs in bioreactors and other environments during remediation of contaminated waters.

Biodegradation, Environmental↗
PubMed1990

Use of oligodeoxynucleotide signature probes for identification of physiological groups of methylotrophic bacteria.

Oligodeoxynucleotide sequences that uniquely complemented 16S rRNAs of each group of methylotrophs were synthesized and used as hybridization probes for the identification of methylotrophic bacteria possessing the serine and ribulose monophosphate (RuMP) pathways for formaldehyde fixation. The specificity of the probes was determined by hybridizing radiolabeled probes with slot-blotted RNAs of methylotrophs and other eubacteria followed by autoradiography. The washing temperature was determined experimentally to be 50 and 52 degrees C for 9-alpha (serine pathway) and 10-gamma (RuMP pathway) probes, respectively. RNAs isolated from serine pathway methylotrophs bound to probe 9-alpha, and RNAs from RuMP pathway methylotrophs bound to probe 10-gamma. Nonmethylotrophic eubacterial RNAs did not bind to either probe. The probes were also labeled with fluorescent dyes. Cells fixed to microscope slides were hybridized with these probes, washed, and examined in a fluorescence microscope equipped with appropriate filter sets. Cells of methylotrophic bacteria possessing the serine or RuMP pathway specifically bind probes designed for each group. Samples with a mixture of cells of type I and II methanotrophs were detected and differentiated with single probes or mixed probes labeled with different fluorescent dyes, which enabled the detection of both types of cells in the same microscopic field.

Base Sequence↗
PubMed1990

Mechanism of sympathetic neural regulation of insulin, somatostatin, and glucagon secretion.

The effects of electrical stimulation of the left splanchnic nerve on insulin, somatostatin, and glucagon secretion from the isolated perfused rat pancreas were investigated. Electrical splanchnic nerve stimulation (SNS), performed by square-wave impulses, produced a 25% decrease in effluent flow and a 10-fold increase in perfusate norepinephrine. Both insulin and somatostatin output in the presence of 16.7 mM glucose were inhibited during SNS by 85 and 56% of the basal value, respectively. Glucagon output in the presence of 5.5 mM glucose was stimulated 20-fold by SNS. Perfusion with 10(-6) M propranolol further decreased insulin and somatostatin output during SNS, when expressed as the total decrement beneath basal during stimulation. The glucagon response to SNS tended to be enhanced, although not significantly, by simultaneous infusion of 10(-6) M propranolol. However, 10(-6) M phentolamine (Phe) attenuated the SNS-induced inhibition of insulin and somatostatin output by 50 and 40%, respectively. However, insulin output remained decreased after SNS with Phe. The SNS-induced glucagon response was completely abolished by 10(-6) M Phe alone or by 10(-6) M Phe plus 10(-6) M propranolol. With 10(-6) M Phe plus 10(-6) M propranolol, insulin and somatostatin output remained decreased after SNS. These results suggest that insulin and somatostatin secretions induced by glucose are inhibited during SNS through the alpha-adrenergic mechanism and also that the beta-adrenergic mechanism exerts a stimulatory action. SNS-induced glucagon secretion occurs mainly through alpha-adrenergic activation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

[Fertility study of cefpirome sulfate in rats].

A fertility study was performed in rats by intraperitoneal administration of cefpirome sulfate (CPR) at dose levels of 0 (control), 200, 400 and 800 mg/kg/day. Male rats were treated for 60 days before mating and during the mating period. Female rats were administrated the substance from 14 days before mating to day 7 of pregnancy. The females were sacrificed on day 21 of pregnancy for examination of their fetuses. No animal died during the administration period. Loose feces were observed in both male and female animals in the 400 and 800 mg/kg/day groups. Body weight gain was suppressed in both male and female animals in the 800 mg/kg/day group and in male animals in the 400 mg/kg/day group. There were no significant differences in food and water intakes between treated and control groups. Autopsy revealed the enlargement of the caecum in males in the 200, 400 and 800 mg/kg/day groups. The kidney and adrenal weights were significantly increased in males in the 200, 400 and 800 mg/kg/day groups. Fertility and reproductive ability in both sexes, and estrus cycles in female rats were not affected by administration of CPR. There were no lethal effect and growth-inhibiting or teratogenic effects on the embryos and the fetuses. The results suggest that the non-effective dose level of CPR was lower than 200 and 200 mg/kg/day for general toxicity in male and female parent animals respectively, 800 mg/kg/day for reproductive ability in parent animals and in embryos and fetuses.

Abnormalities, Drug-Induced↗
PubMed1990

[Teratological study of cefpirome sulfate in rats].

A teratogenicity study was performed in rats by intraperitoneal or intravenous administration of cefpirome sulfate (CPR) at dose level of 0 (control), 200, 400 and 800 mg/kg/day to dams from day 7 to day 17 of pregnancy. Twenty one to twenty eight female rats in each intraperitoneal and intravenous administrated group were sacrificed on day 21 of pregnancy for examination of their fetuses, and ten to thirteen female rats in each intraperitoneal administrated group were allowed to deliver for the postnatal examination of their offsprings. In the 800 mg/kg/day intravenous administrated group, two dams out of twenty four died during administration period, however no animal died in any intraperitoneal administrated group. The doses of 400 and 800 mg/kg/day caused piloerection, diarrhea or loose feces in the both administration routes, and accelerated breathing, a decrease in spontaneous activity, systemic spasms, cataleptic symptoms and wild running in the intravenous route. The suppression of body weight gain was detected in the 800 mg/kg/day intraperitoneal administrated group and 200, 400 and 800 mg/kg/day intravenous administrated groups, however there were no significant differences in food and water intakes between treated and control groups. At autopsy, enlargement of caecum and an increase in adrenal weight were detected in the 800 mg/kg/day groups of both administration routes. Body weight of the fetuses was decreased in both sexes in the 800 mg/kg/day group and in male fetuses in the 400 mg/kg/day group, and placental weight was decreased in the 800 mg/kg/day group, in the both administration routes respectively. However, embryonal or fetal mortality and incidences of external or visceral anomalies were not increased. In offspring, the dose of 800 mg/kg/day caused very slight suppression of body weight gain, however CPR had no adverse effects on the postnatal development such as viability, differentiation, emotionality, learning ability or reproductive performance. The results suggest that the non-effective dose level of CPR is 200 mg/kg/day in maternal animals and fetuses, 400 mg/kg/day in offsprings in intraperitoneal route, lower than 200 mg/kg/day in maternal animals and 200 mg/kg/day in fetuses in intravenous route respectively.

Abnormalities, Drug-Induced↗
PubMed1990

[Perinatal and postnatal study of cefpirome sulfate in rats].

A perinatal and postnatal study was performed in rats by intraperitoneal administration of cefpirome sulfate (CPR) at dose levels of 0 (control), 200, 400 and 800 mg/kg/day to dams from day 17 of pregnancy to day 21 after delivery. Twenty one or twenty two dams in each group were allowed to deliver for the postnatal examination of their offsprings. No animal died. Loose feces were observed in the 800 mg/kg/day group. Body weight gain of the dams was retarded in the 800 mg/kg/day group in the early stage of treatment. Food intake was reduced simultaneously in the 200, 400 and 800 mg/kg/day groups. Autopsy revealed the enlargement of caecum in the 800 mg/kg/day. The adrenal weight was increased in the 400 and 800 mg/kg/day groups, and the kidney weight was increased in the 800 mg/kg/day group. The body weight of pups at birth in the 800 mg/kg/day group was slightly lower than that in the control group. The body weight of male pups in the 800 mg/kg/day group decreased transiently during rearing period. However, CPR had no adverse effects on the postnatal development such as viability, differentiation, emotionality, learning ability or reproductive performance. The results suggest that the non-effective dose level of CPR is lower than 200 mg/kg/day for general toxicity, 800 mg/kg/day for reproductive ability in maternal animals and 400 mg/kg/day in offsprings respectively.

Abnormalities, Drug-Induced↗
PubMed1990

Availability of 4'galactosyllactose (O-beta-D-galactopyranosyl-(1----4)-O-beta-D-galactopyranosyl-(1----4)- D-glucopyranose) in rat.

O-beta-D-Galactopyranosyl-(1----4)-O-beta-D-galactopyranosyl-(1----4)-D- glucopyranose (designated as 4'GL) is produced from lactose by Cryptococcus laurentii. The influence of chronic ingestion of 4'GL on body weight gain, organ weight, serum lipids, and liver lipids was investigated in rats. The body weight gains of the 5% and 10% 4'GL-diet groups were higher than that of the control group. Food intake and fecal dry weight were significantly increased (p less than 0.05) by 4'GL feeding. The 4'GL diet produced a significant increase (p less than 0.01) in the wet weight and contents of both the cecum and the colon. However, no significant increase was observed in the weight of the stomach, small intestine, liver, or other organs. The effects of 4'GL on serum and liver lipid levels were not observed in this experiment. The digestion of 4'GL was measured in vitro using the artificial gastric juice, alpha-amylase of human saliva, alpha-amylase of hog pancreas, and mucosa of rat intestine. 4'GL was not hydrolyzed by these enzymes. Long-term ingestion of 4'GL did not cause any induction of 4'GL hydrolyzing enzyme activity in the rat small intestine.

Animals↗
PubMed1990

[DNA damage test in forestomach squamous epithelium of F344 rat following oral administration of ethyl acrylate].

The alkaline elution assay were applied for testing DNA damage of forestomach squamous epithelium in male F344 rat after oral administration of ethyl acrylate (EA), a forestomach carcinogen. The animals were starved for 18 hr and then given a single oral dose of EA. No DNA damage were observed by EA at the concentration of 0.1-4.0%. The weights of the forestomach increased with EA dose, reflecting edema and inflammation, but that of glandular stomach did not change with its dose.

Acrylates↗