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Biomedical subjects

H Kuroki

Publications and source records attributed to H Kuroki.

At least 73 records · Page 4Linked to original sources
PubMed1995

Detection of D1S80 (pMCT118) locus polymorphism using semi-nested polymerase chain reaction in skeletal remains.

We evaluated the usefulness of a semi-nested polymerase chain reaction (PCR) method for detecting D1S80 (pMCT118) locus polymorphisms of DNA extracted from old skeletal remains. The semi-nested PCR has been applied to the amplification of D1S80 nucleic acid sequences. For amplification of the locus D1S80, a pair of oligonucleotide primers have been used widely as described by Kasai et al. We have designed another set of primers for semi-nested PCR. This method resulted in D1S80-VNTR detection from low-titered DNA isolated from old skeletal remains. The first and second step PCR achieved amplification from as little as 10 ng and 10 pg of template DNA, respectively. Specificity and sensitivity of the amplification products was markedly improved by semi-nested PCR. In DNA extracted from biological samples, this method took about 5 hours to amplify the target DNA and 3 hours for electrophoretic separation. We demonstrated that this semi-nested PCR method was superior in sensitivity to conventional 1-step standard amplification for VNTR typing of the D1S80 locus.

Base Sequence↗
PubMed1995

[Preliminary studies on the retention of hydroxylated PCDF metabolites in rat blood].

We recently reported that certain hydroxylated PCB (OH-CB) metabolites were selectively retained in blood of rats experimentally dosed with PCB (Aroclor 1254), and also in blood of seals and humans environmentally exposed to PCBs. We also showed that metabolism in vivo of polychlorinated dibenzofurans (PCDFs) gave rise to a large number of hydroxylated PCDF (OH-CDF) metabolites, excreted in faeces, after oral administration to rats of PCDFs mixture (1, 2, 7, 8-tetraCDF 14%, 2, 3, 7, 8-tetraCDF 35%, 1, 2, 3, 7, 8-pentaCDF 48%). These results suggest that OH-CDFs could be present in blood. In the present study, potential retention of OH-CDF metabolites in blood (serum) was investigated in a female Wistar rat exposed to the PCDFs mixture. Serum was analyzed for the methylated OH-CDFs by gas chromatography (GC) and GC-mass spectrometry. Two major metabolites were determined in serum 1 day after oral administration. These were identified to be 3-OH-2, 4, 7, 8-tetraCDF (A) and 3-OH-2, 4, 7, 8, 9-pentaCDF (B) by comparison with synthesized reference compounds. 3-OH-2, 4, 7, 8-tetraCDF and 1, 2, 3, 7, 8-pentaCDF, respectively, via 3, 4(6, 7)-epoxide intermediate and subsequent NIH-shift of the 3(7)-chlorine to the 4(6)-position. The amounts of 3-OH-2, 4, 7, 8-tetraCDF and 3-OH-2, 4, 7, 8, 9-pentaCDF in the serum (5.72 g) analyzed accounted for 0.018% of 2, 3, 7, 8-tetraCDF and 0.003% of 1, 2, 3, 7, 8-pentaCDF dosed, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

[Change of PCDF and PCB concentrations in the blood of Yucheng and Yusho patients for 25 years].

The blood samples of 3 Yucheng patients collected 6-7 times from 1980 to 1993 and 5 Yusho patients collected 6-8 times from 1982 to 1993 were analyzed for congeners of polychlorinated dibenzofurans (PCDF) and polychlorinated biphenyls (PCB) by high resolution gas chromatography-mass spectrometry and gas chromatography-electron capture detection. In the blood of Yucheng patients, the high concentrations of 3 PCDF congeners, 2,3',4, 4',5-penta-CB and 5 PCB congeners were eliminated at half-lives of 2.4-2.9, 1.7 and 4.1-6.1 years, respectively, while in Yusho patients, 14 years after the incident, their half-lives were converted to longer times as observed 3.2-13.4, 24.0 and 13.7-34.2 years, respectively. In the same Yucheng and Yusho patients, the half-lives of the 5 PCB congeners were about twice longer than those of the 3 PCDF congeners. PCBs are more retainable than PCDFs in human blood.

Adult↗
PubMed1995

Effect of 2, 3, 4, 7, 8-pentachlorodibenzofuran and its analogues on induction of sister chromatid exchanges in cultured human lymphocytes.

We have been already contaminated with various chemicals including highly toxic organochlorine compounds such as 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD), 2, 3, 4, 7, 8-pentachlorodibenzofuran (PenCDF) and 3, 4, 5, 3', 4'-pentachlorobiphenyl (Co-PenCB). In this study, in order to evaluate the genotoxicity of the three chemicals, we have examined their effects on the induction of sister chromatid exchanges (SCEs), which has been frequently utilized as an indicator of biological and genetic damage due to exposure to carcinogens or mutagens, in cultured human lymphocytes in the absence or presence of 7, 8-benzoflavone (ANF) and the following results were obtained. 1) TCDD, PenCDF and Co-PenCB significantly increased the frequency of SCEs with almost the same dose-dependent manner in terms of the concentration of TCDD toxic equivalent. 2) 8 x 10(-5) MANF significantly enhanced the frequency of SCEs and the simultaneous treatment of ANF and either of TCDD, PenCDF or Co-PenCB seemed to exert an additive effect as SCEs inducer. 3) TCDD, PenCDF and Co-PenCB were considered to be very potent inducers of SCEs, because their 50% effective concentration in SCEs enhancement were only 5 to 10 times higher than the level of the adipose tissue in healthy Japanese, namely, 70ppt as TCDD. Consequently, the respective TCDD toxic equivalency factors of 0.5 and 0.2 for PenCDF and Co-PenCB seemed to be reasonable so far as the induction of SCEs was employed as an indicator of the genotoxic potency.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Influence of five methylsulphonyl PCB congeners on frequency of micronucleated cells in cultured human lymphocytes by cytokinesis block method.

The lungs and blood of Yusho patients and healthy Japanese people have already been contaminated with methylsulphonyl polychlorinated biphenyls (MSF-PCBs) at relatively high concentration. Therefore, we should give due attention to their biological and toxicological effects to man. In this study, in order to mainly evaluate non-S-dependent genotoxicity of five MSF-PCB congeners, namely, 3-MSF-4, 5, 3', 4'-tetrachlorobiphenyl (TCB), 3-MSF-4, 5, 2', 3'-TCB, 3-MSF-2, 5, 2', 4', 5'-pentachlorobiphenyl (PenCB), 4-MSF-2, 5, 2', 3', 4'-PenCB and 4-MSF-2, 5, 2', 3', 5', 6'-hexachlorobiphenyl (HCB). We have examined their effects on the induction of micronucleated cells, which has been frequently used to estimate the dose of ionizing radiation and truly radiomimetic, non-S-dependent, clastogens, in cultured human lymphocytes in the absence or presence of 2, 3, 4, 7, 8-pentachlorodibenzofuran (PenCDF), 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD) or 3, 4, 5, 3', 4'-pentachlorobiphenyl (Co-PenCB). The following results were obtained. 1) 4 x 10(-5) M7, 8-benzoflavone (ANF) significantly enhanced the frequency of micronucleated cells and all of the five MSF-PCB congeners failed to induce the formation of micronucleated cells at doses of 5.2 to 9.6 ppm, which were about 35,000 times higher than the concentrations in the lungs and adipose tissue of healthy Japanese people.(ABSTRACT TRUNCATED AT 250 WORDS)

Cells, Cultured↗
PubMed1995

[Making a backlight display panel using a personal computer and a laser imager: a less expensive and less time-consuming method].

To make a backlight display panel for a scientific exhibit, we used a commercially available laser imager. The MR image was directly transferred from the MR apparatus to a personal computer, and other image information was transferred through an image scanner or digital camera. Text for the presentation was made on the commercially available presentation software Persuasion. It took approximately 10 minutes to print out all the panels needed for one exhibit, and cost only 3,600 Yen (600 Yen a film).

Audiovisual Aids↗
PubMed1994

Experimental challenge for the treatment of Duchenne muscular dystrophy using a vascularized free muscle graft.

Following free vascularized normal muscle graft in mice, a study was made to determine whether dystrophin expression is possible in dystrophin-deficient muscles. In this study, dystrophic C57BL/10 ScSn-mdx mice were used as recipients and normal C57BL/10 ScSn mice as donors. A free vascularized quadriceps muscle 8.0 x 6.0 x 6.0 mm in size was orthotopically transplanted into a muscle defect produced in the recipient mouse. The diameter of the sutured vessels was about 0.4 mm. Transplantation was successful in 7 of 20 mice. At 12 weeks after the transplantation, the grafted muscle was examined by immunocytochemical stain using anti-dystrophin antibody. This study showed that dystrophin was expressed in the transplanted muscle but not in the adjacent recipient quadriceps muscle, suggesting that grafted donor cells with dystrophin failed to migrate into dystrophic muscle cells and fuse together. However, since the grafted normal skeletal muscle successfully survived and normal dystrophin was expressed in almost all the grafted muscle fibers, the possibility was suggested that the function of muscular dystrophy muscle can be compensated by complete replacement with a larger muscle.

Animals↗
PubMed1994

Relationship between insulin resistance and risk factors for cardiovascular disease in Japanese non-insulin-dependent diabetic patients.

To investigate whether a resistance to insulin-stimulated glucose uptake (IR) is associated with the risk factors (RF) for cardiovascular disease (CVD) in non-insulin-dependent diabetic (NIDDM) patients, we determined the degree of IR in 135 adult NIDDM patients who had no advanced diabetic complications. The euglycemic (80 mg/dl) hyperinsulinemic clamp (insulin infusion rate 1.12 mU/kg per min) was performed and the average glucose infusion rate (GIR) during a steady-state euglycemia was determined as a measure of IR. Hypertension was more common among NIDDM patients with an increased IR and was highest in the group of patients with CVD. CVD-RF such as hypertension, hypertriglyceridemia, low HDL-cholesterol and obesity tended to cluster in the NIDDM patients who had lower GIR values and higher fasting IRI levels. GIR values were compared between a set of groups extracted from the 135 NIDDM patients that were matched for age, sex, body mass index and HbA1c levels. The CVD-positive group had the significantly lower GIR value than the CVD-negative group (2.06 +/- 0.66 vs. 3.45 +/- 1.75, P < 0.005). The GIR value was also significantly lower in the hypertriglyceridemic group compared with the normotriglyceridemic group (2.50 +/- 1.36 vs. 4.03 +/- 1.82, P < 0.0005). However, there was no significant difference between the hypertensive and normotensive groups and between the high cholesterol or low HDL-cholesterol groups and their respective control groups. In conclusion, these results suggest that IR contributes to the clustering of CVD-RFs which may accelerate the development of CVD in the subgroup of Japanese NIDDM patients.

Adult↗
PubMed1994

Ipsilateral osteochondral grafting for finger joint repair.

A method for reconstructing articular osteochondral defects of the joint surfaces of the fingers is described. An osteochondral graft was harvested from the distal or proximal side of the second or third carpometacarpal joint of the ipsilateral hand. The graft was subsequently transplanted to the site of the defect in the proximal or distal interphalangeal joint. Ten cases with a follow-up period of more than 2 years were reviewed. The mean angular deformity decreased from 33 degrees to 4 degrees, and the mean active range of motion increased from 22 degrees to 38 degrees. Plain x-ray films revealed good joint congruity, and no donor site morbidity was appreciated. This treatment approach may be particularly useful in children.

Adult↗
PubMed1994

Selective retention of hydroxylated PCB metabolites in blood.

Polychlorinated biphenyls (PCBs) are important environmental contaminants, and their toxicity to wildlife and humans are of major concern. PCBs form persistent and abundant metabolites, PCB methyl sulfones, that accumulate in biota. We now report that certain hydroxylated PCB metabolites show a strong and selective accumulation in mammalian blood. Plasma from experimentally PCB-dosed rats and blood from environmentally exposed grey seals (Halichoerus grypus) and humans were analyzed. Among all possible hydroxylated metabolites of PCB that may be formed, only a few, dominated by 4-OH-2,3,5,3',4'-pentachlorobiphenyl and 4-OH-2,3,5,6,2',4',5'-heptachlorobiphenyl, were found in the blood samples. All identified compounds have a structure with the hydroxy group in a para or meta position, with chlorine atoms on vicinal carbon atoms. The concentrations of hydroxylated PCB in the blood were almost in the same range as the most persistent PCB congeners both for seals and humans.

Adult↗
PubMed1994

Physiological increase in plasma insulin concentration suppresses proinsulin secretion in normal controls but not in subjects with glucose intolerance.

Since insulin negatively controls its own secretion, we examined if insulin also inhibits the secretion of its precursor, proinsulin, in subjects with varying degrees of glucose tolerance. Under comparable hyperinsulinemia (50-70 microU/ml) achieved by the euglycemic insulin clamp technique, plasma C-peptide concentrations were equally suppressed to approximately 40-50% in nonobese subjects with normal glucose tolerance (NGT) (n = 13, 35.5 +/- 3.7%, M +/- SEM), borderline glucose intolerance (BGI) (n = 12, 46.7 +/- 5.6%), and non-insulin-dependent diabetes mellitus (NIDDM) (n = 12, 48.9 +/- 5.4%). In contrast, plasma proinsulin concentrations were slightly but significantly suppressed in NGT (4.1 +/- 0.2 to 3.7 +/- 0.2 pmol/L, P < 0.05), but not in patients with BGI (4.6 +/- 0.3 to 4.8 +/- 0.5 pmol/L, NS) and NIDDM (5.5 +/- 0.5 to 4.9 +/- 0.4 pmol/L, NS). The basal concentrations of proinsulin increased as glucose tolerance declined (P < 0.05 between NGT and NIDDM). These results suggest that the basal secretion of proinsulin by beta-cells seems relatively insensitive to insulin compared with C-peptide, and that the insulin-proinsulin feedback loop is disturbed in glucose-intolerant subjects. Therefore, a defective feedback inhibition of proinsulin secretion by insulin may be partly involved in the disproportionate increase of plasma proinsulin concentrations in patients with NIDDM.

Adult↗
PubMed1994

Metabolism of 3,5,3',5'-tetrachlorobiphenyl by rat liver microsomes and purified P4501A1.

1. The metabolism of 3,5,3',5'-tetrachlorobiphenyl (TCB) was investigated with liver microsomes and purified P450 from the male Wistar rat. 2. One novel metabolite was produced after incubation with liver microsomes derived from the 3-methylcholanthrene (MC)- and 3,4,5,3',4'-pentachlorobiphenyl-pretreated rat, but not after incubation with those from the untreated or phenobarbital (PB)-pretreated rat. These results suggest that P450 isozyme(s) induced by MC-type inducers is involved in 3,5,3',5'-TCB metabolism. 3. The chemical structure of this metabolite was identified to be 4-hydroxy-3,5,3',5'-TCB by comparison of its retention time in glc and the ms with those of a synthetic sample. 4. Purified rat P4501A1, a major MC-inducible P450 isozyme, catalyzed the 4-hydroxylation of 3,5,3',5'-TCB, but P4502B1, a major PB-inducible isozyme, was inactive. 5. Reduced glutathione completely inhibited the formation of the hydroxylated metabolite, suggesting that 4-hydroxylation of 3,5,3',5'-TCB proceeded via the 3,4-epoxide.

Animals↗
PubMed1994

[Clinical evaluation of a new carbapenem antibiotic, biapenem (L-627), in the pediatric field].

Biapenem (L-627) was evaluated for its safety and efficacy in 27 children with various bacterial infections. L-627 was effective in cases with osteomyelitis due to Staphylococcus aureus, pneumonia and purulent meningitis due to penicillin-resistant Streptococcus pneumoniae, and urinary tract infections due to Enterococcus faecalis, Escherichia coli, or Pseudomonas aeruginosa. However, L-627 failed to produce good responses in 2 of 7 cases of Haemophilus influenzae infections. Pharmacokinetic parameters of 30-minutes infusion of 12 mg/kg were as follows: Cmax 29-46 micrograms/ml, T 1/2 0.68-0.94 hr. Adverse reactions were minimal. These data suggest that L-627 is safe in children, and is valuable especially for treatment of infections in immunocompromised hosts and infections due to multiply resistant bacteria.

Adolescent↗
PubMed1994

[An adult case of congenital esophagobronchial fistula complicated with pyothorax].

A 64-year-old woman with congenital esophagobronchial fistula complicated with pyothorax is reported. She was admitted to our hospital because of high fever and cough. Chest X-ray showed a cavity with niveau in the right lower lobe. The next day she noticed right chest pain. Chest X-ray showed right pleural effusion. The diagnosis of left esophagobronchial fistula with pyothorax was confirmed by esophagography, esophagoscopy, chest X-ray and chest CT. After treatment of the pyothorax with antibiotics and drainage, fistulectomy and right lower lobectomy were performed. The postoperative course was uneventful. Histologically, the fistula had esophageal epithelium with a submucosal muscle layer and demonstrated a transitional zone between squamous epithelium and bronchial epithelium.

Bronchial Fistula↗
PubMed1993

Elimination of polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) from human blood in the Yusho and Yu-Cheng rice oil poisonings.

The pharmacokinetics of polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) in humans was studied by monitoring the blood concentrations of individuals who ingested a contaminated rice oil in Japan (yusho) in 1968 and in Taiwan (yu-cheng) in 1979. Sixteen yusho patients were followed from 1982 to 1990 and three yu-cheng individuals from 1980 to 1989. From the three yu-cheng patients, blood lipid values for the two persistent toxic congeners, 2,3,4,7,8-pentachlorodibenzofuran (PnCDF) and 1,2,3,4,7,8-hexachlorodibenzofuran (HxCDF), varied from 50 micrograms/kg at first sampling to about 1 micrograms/kg at last sampling corresponding to half-lives for elimination (t1/2) of 2-21/2 years. The blood lipid values for the same PCDF congeners in yusho patients varied from 5 micrograms/kg down to 0.1 micrograms/kg. The calculated t1/2 were more variable with median values closer to 10 years. Planar PCBs #126 and #169 were present at lower concentrations than the PCDFs. For seven of the other PCB congeners, half-lives for elimination in the yu-cheng individuals varied from 1.2 up to 4.6 yr depending on the degree of chlorination. For the yusho patients, the elimination for the PCBs was longer. These results show that clearance of the toxic PCDFs and PCBs in humans is non-linear with faster elimination at higher exposure followed by slower decreases as background levels are approached. Such a clearance pattern can best be explained by a two compartment liver and fat pharmacokinetic model.

Adolescent↗
PubMed1993

Biosynthesis of polyesters from various amino acids by Alcaligenes eutrophus.

The possibilities of the biosynthesis of polyesters from 20 kinds of naturally occurring L-amino acids by Alcaligenes eutrophus were studied. It was found that several amino acids were used efficiently to synthesize copolyesters of 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3 HV) by A. eutrophus under the 'loose nitrogen-limiting' condition, but the other amino acids were scarcely utilized as a carbon source for the synthesis of polyesters. When L-threonine or L-isoleucine were used as the sole carbon source, copolyesters with higher 3HV content were produced.

3-Hydroxybutyric Acid↗
PubMed1993

[Two cases of methicillin-resistant Staphylococcus aureus infection].

We have experienced 2 cases of MRSA infection. Case 1: A 16 month-old girl, whose underlying disease was VAHS, had chronic sinusitis. MRSA was isolated from the blood and rhinorrhea. Her sinusitis was very intractable and it was difficult to eradicate MRSA from the nare. Case 2: A 6-months-old girl was admitted to our hospital with urinary tract infection. She had an ectopic uretelocele. Partial nephrectomy and uretectomy was performed. Retroperitoneal and intraperitoneal abscess had recurred three times during 17 months after the first operation. This abscess was slowly progressive and MRSA was very difficult to eradicate. These 2 cases showed characteristics of MRSA infection.

Anti-Bacterial Agents↗