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Biomedical subjects

K Tanaka

Publications and source records attributed to K Tanaka.

At least 37 records · Page 2Linked to original sources
PubMed1992

Opposite effects of rough and gentle handling with repeated saline administration on c-fos mRNA expression in the rat brain.

The rough handling with repeated saline administration (1.2 ml/kg s.c. for 7 days) enhanced cortical c-fos mRNA expression in the rat brain after a single saline stimulation (1.2 ml/kg s.c.) due to increasing baseline c-fos mRNA levels, whereas the gentle handling with repeated saline administration declined c-fos mRNA expression after a single injection due to decreasing the baseline of c-fos mRNA levels. These two types of handling with the repeated injection led to diametrically opposite results on c-fos mRNA expression after a single stimulation. Neither two types of handling with repeated saline injections affected the net increment of c-fos mRNA induction after a single stimulation, therefore, the effects of handling with repeated treatment on c-fos mRNA expression might be independent of the effects of a single saline stimulation. The present study suggests that c-fos mRNA induction after a single stimulation might be affected by the types or intensities of handling and that care must be taken to estimate c-fos mRNA induction.

Animals↗
PubMed1992

A specific RFLP type associated with the occurrence of sheep scrapie in Japan.

We have investigated restriction fragment length polymorphism (RFLP) on the PrP gene and the frequencies of RFLP patterns in 35 healthy Suffolk sheep randomly collected. According to the combinations of PrP encoding DNA fragments generated by restriction enzymes Eco RI and Hind III, the RFLP patterns were classified into six types and designated as types I to VI. The frequencies of these types were as follows: I, 8.6%; II, 11.4%; III, 17.6%; IV, 11.4%; V, 28.6%; and VI, 22.9%. In 10 sheep diagnosed as having natural scrapie, RFLP types, I, III, IV, and V were determined. To examine the correlation between the RFLP type and the occurrence of scrapie, the frequencies of RFLP types in sheep infected with natural scrapie were compared with those in healthy sheep. It was found that the frequency of type I in the sheep with natural scrapie was 70%, about eight times higher than that in randomly collected healthy sheep. In the 13 experimentally infected sheep that had been used for other purposes, however, no relationship between the RFLP type and onset of scrapie was found.

Animals↗
PubMed1992

Molecular basis of group A xeroderma pigmentosum: a missense mutation and two deletions located in a zinc finger consensus sequence of the XPAC gene.

The molecular basis of group A xeroderma pigmentosum (XP) was investigated, and 3 mutations located in a zinc finger consensus sequence (nucleotide 313-387) of the XP group A complementing (XPAC) gene were identified in 2 Caucasian patients GM2990 and GM2009 who had typical symptoms of group A XP. The first mutation was a C deletion at nucleotide 374. Patient GM2990 was a homozygote for this mutation. The second mutation was a 5-bp deletion (CTTAT) at nucleotides 349-353. The third mutation was a G to T transversion at nucleotide 323 that alters the Cys-108 codon (TGT) to a Phe codon (TTT). Patient GM2009 was a compound heterozygote for the 5-bp deletion and the missense mutation. Both deletions introduce frameshifts with premature translation terminations resulting in instability of the XPAC mRNA and disruption of the putative zinc finger domain of the XPAC protein. The missense mutation also predicts disruption of the zinc finger domain of the XPAC protein. The expression study showed that the missense mutation does indeed causes loss of repair activity of the XPAC protein. We conclude that these 3 mutations are responsible for group A XP.

Amino Acid Sequence↗
PubMed1992

Diffusion coefficient for O2 in plasma and mitochondrial membranes of rat cardiomyocytes.

Oxygen diffusion in plasma membranes and mitochondrial (Mt) membranes of ventricular myocytes isolated from adult rat hearts was measured using O2-induced fluorescence quenching of pyrene-butyric acid. The diffusion coefficient for oxygen (DO2 in 10(-6).cm2 x s-1) of the plasma membrane was 2.91 +/- 0.05 (37 degrees C) in the control group, which was significantly higher than that of Mt membrane (2.23 +/- 0.11) (P < 0.001). The DO2 of the plasma membrane was reduced to 2.50 +/- 0.08 (P < 0.001) in myocytes isolated from heart after 15 min reperfusion following no-flow ischemia for 30 min, while that of the Mt membrane remained almost unchanged. Administration of hydrogen peroxide and hypochlorous acid to the isolated myocytes also reduced the plasma membrane DO2. The decrease in the plasma membrane DO2 correlated with that in the fraction of rod-shaped myocytes. We conclude that the plasma membrane is more susceptible to reperfusion injury than the Mt membrane, but these membranes do not limit O2 uptake in the heart because of the high absolute values of DO2.

Animals↗
PubMed1992

Biological activity of subfractions from scrapie-associated fibrils.

Subfractions, a nucleic acid fraction and a PrP fraction consisting of PrP17-25, a core fragment of PrPsc, were prepared from the scrapie-associated fibril-enriched fraction from scapie-affected mouse brains. The nucleic acid fraction consisted mainly of variously fragmented DNA and no scrapie-specific nucleic acid was detected in the fraction by SDS polyacrylamide gel electrophoresis. To examine the biological activity, the nucleic acid fraction was either first introduced into mouse L-929 cells before or after nuclease treatments, then transfected cell lysates prepared 2 weeks later were inoculated into mice, or directly inoculated into mice with or without the PrP fraction. The PrP fraction alone was also inoculated into mice. Mice inoculated with the transfected cell lysates or with the nucleic acid fraction alone showed no scrapie signs during their lifespan or the observation period. While 60% of the mice inoculated with the PrP fraction alone and 67% of those inoculated with the fraction together with the nucleic acid fraction showed clinical signs of scrapie. A nucleic acid molecule bound covalently to PrP17-25 was not detected. The results obtained by the present procedures so far suggest scrapie infectivity to be associated with PrPsc, which does not contain any detectable scrapie-genome molecule as either free or covalently bound nucleic acid.

Animals↗
PubMed1992

Effects of pantethine on lipogenesis and CO2 production in the isolated hepatocytes of the chick (Gallus domesticus).

1. Isolated hepatocytes from chicks were used to study the effects of pantethine supplementation to incubation medium on in vitro lipogenesis, CO2 production and beta-oxidation of fatty acid. 2. In vitro lipogenesis, determined by the incorporation of 1-[14C]acetate into total lipid and various lipid fractions, as depressed in concordance with the increase of pantethine concentration in the medium. 3. Incubation of isolated hepatocytes with pantethine resulted in a significant decrease (P < 0.01) in the activities of acetyl-CoA carboxylase and fatty acid synthetase. 4. The results suggest that in vitro fatty acid synthesis from 1-[14C]acetate was depressed and CO2 production was elevated in hepatocytes of chicks through pantethine addition to the medium at a low level.

Animals↗
PubMed1992

Three nonsense mutations responsible for group A xeroderma pigmentosum.

The molecular basis of xeroderma pigmentosum (XP) group A was studied and 3 nonsense mutations of the XP-A complementing gene (XPAC) were identified. One was a nucleotide transition altering the Arg-228 codon (CGA) to a nonsense codon (TGA). This transition creates a new cleavage site for the restriction endonuclease HphI. Of 21 unrelated Japanese XP-A patients examined, 1 (XP39OS) was a homozygote for this mutation and 3 were compound heterozygotes for this mutation and for the splicing mutation of intron 3 reported previously which is the most common mutation in Japanese patients and creates a new cleavage site for the restriction endonuclease AlwNI. The second mutation was a nucleotide transition altering the Arg-207 codon (CGA) to a nonsense codon (TGA). A Palestinian patient (XP12RO) who had severe symptoms of XP was homozygous for this mutation. The third mutation was a nucleotide transversion altering the Tyr-116 codon (TAT) to a nonsense codon (TAA). This transversion creates a new cleavage site for the restriction endonuclease MseI. Of the Japanese patients, 2 with severe clinical symptoms had this mutant allele. One was a compound heterozygote for this mutation and for the splicing mutation, and the other was heterozygous for this mutation and homozygous for the splicing mutation. Although most XP-A patients such as XP12RO have severe skin symptoms and neurological abnormalities of the de Sanctis-Cacchione syndrome, patient XP39OS was an atypical XP-A patient who had mild skin symptoms and minimal neurological abnormalities. Our results suggest that the clinical heterogeneity in XP-A is due to different mutations in the XPAC gene. Moreover, our data indicate that almost all Japanese cases of XP-A are caused by one or more of the 3 mutations, i.e., the splicing mutation of intron 3 and the 2 nonsense mutations of codons 116 and 228. Therefore, by restriction fragment length polymorphism analysis of PCR-amplified DNA sequences using the 3 restriction enzymes described above, rapid and reliable diagnosis of XP-A can be achieved in almost all Japanese subjects including prenatal cases and carriers.

Base Sequence↗
PubMed1992

Identification of splicing mutations of the last nucleotides of exons, a nonsense mutation, and a missense mutation of the XPAC gene as causes of group A xeroderma pigmentosum.

Four mutations of the XPAC gene were identified as molecular bases of different UV-sensitive subgroups of xeroderma pigmentosum (XP) group A. One was a G to C transversion at the last nucleotide of exon 4 in GM1630/GM2062, a little less hypersensitive subgroup than the most sensitive XP2OS/XP12RO. The second mutation was a G to A transition at the last nucleotide of exon 3 in GM2033/GM2090, an intermediate subgroup. Both mutations caused almost complete inactivation of the canonical 5' splice donor site and aberrant RNA splicing. The third mutation was a nucleotide transition altering the Arg-211 codon (CGA) to a nonsense codon (TGA) in another allele of GM2062. The fourth mutation was a nucleotide transversion altering the His-244 codon (CAT) to an Arg codon (CGT) in XP8LO, an intermediate subgroup. Our results strongly suggest that the clinical heterogeneity in XP-A is due to different mutations in the XPAC gene.

Adolescent↗
PubMed1992

The physiological role of estradiol 17-sulfate during pregnancy.

To clarify the physiological role of estradiol 17-sulfate (ES) during pregnancy, experiments were conducted and the following results were obtained: (1) serum or urinary ES levels rose as a function of gestational age; (2) placental microsomes showed fairly high 2- and 4-hydroxylase activity for ES; and (3) the catechol products, 2- and 4-hydroxy-ES, had a strong inhibitory effect upon the in vitro production of lipid peroxides. These results suggest that ES acts as a precursor to the catechol metabolites which maintain normal gestation. This is coincident with the negative correlation of serum levels in ES and lipid peroxides observed in late pregnancy.

Chromatography, High Pressure Liquid↗
PubMed1992

Hepatoblastoma in a 2-year-old girl with trisomy 18.

A very rare case of mosaic type trisomy 18 associated with hepatoblastoma is described. The patient underwent an extended right hepatic lobectomy at 2 years of age, and the resected tumor was diagnosed as a fetal type dominant hepatoblastoma. The results of chromosome analysis demonstrated that in the peripheral blood and skin, the trisomy 18 cells were 80% and 67%, respectively. On the other hand, although virtually 100% of the cells in the normal liver tissue were 46, XX, about one third of the cells were trisomy 18 in the tumor tissue. At 2 years and 9 months after the operation, the patient was generally healthy and had no evidence of recurrence.

Carcinoma, Hepatocellular↗
PubMed1992

Effect of fenbufen on the pharmacokinetics of sparfloxacin in rats.

The effects of fenbufen on the serum concentrations and penetration into the brain and CSF of sparfloxacin (AT-4140), a new quinolone antibacterial agent, were investigated in rats. At designated times after a bolus iv dose of sparfloxacin 10 mg/kg with or without fenbufen 20 mg/kg, arterial blood, CSF and whole brain were simultaneously collected from each rat. Sparfloxacin concentrations were assayed by HPLC. Serum concentration of sparfloxacin declined bi-exponentially with time and was not changed by coadministered fenbufen. Binding sparfloxacin to serum protein slightly decreased after the coadministration. No elevation of sparfloxacin concentrations was observed in either brain or CSF after coadministration with fenbufen except for only a few time-points. The pharmacokinetic analysis based on the physiological model indicated that fenbufen did not affect the permeability across the blood-brain or blood-CSF barrier. These results suggest that fenbufen may be unlikely to affect the pharmacokinetics, involving the entry into the central nervous system, of sparfloxacin.

Algorithms↗
PubMed1992

An appraisal of pediatric liver transplantation from living relatives. Initial clinical experiences in 20 pediatric liver transplantations from living relatives as donors.

The authors performed 20 liver transplantations from living related donors between June 1990 and July 1991. The 20 pediatric patients (14 biliary atresia, two Budd-Chiari syndrome, one liver cirrhosis after hepatitis C viral infection (HCV hepatitis), 1 progressive intrahepatic cholestasis, 1 liver cirrhosis, 1 protoporphyria) were transplanted with 11 left lobes, eight left lateral segments, and one right lobe. The choice of donors was restricted to the parents of the recipients. The immunosuppressive treatment consisted of FK 506 and steroids. Seventeen recipients are alive, 15 of whom are well and at home. Two recipients, who underwent emergency transplantation, died of postoperative complications. Another recipient died of accidental asphyxia at 6 months after the transplantation. All 20 donors had uneventful postoperative courses and were able to resume their normal social lives. The arterial ketone body ratio (AKBR) increased to above 1.0 within 2 days after the transplantation in all cases. Relatively mild rejection episodes were encountered in only two cases transplanted with ABO-compatible grafts, and these were treated successfully with steroids and FK 506.

Adolescent↗
PubMed1992

Clonal variation of chromosome size derived from the rDNA cluster region in Candida albicans.

Of the eight Candida albicans chromosomes, chromosome 2, assigned by the MGL1 probe, is more variable in size than the other chromosomes among strains. We found that the clonal variation of chromosome 2, which carries a rDNA gene, occurred at a frequency of up to 10% of the progeny clones. After total chromosomal digestion with XhoI, which has no recognition sites within the rDNA repeat unit, the fragments containing the rDNA cluster were detected by Southern hybridization. The difference in fragment sizes corresponded to the clonal size variation of chromosome 2. The intensity of hybridization with rDNA also correlated with the difference in size. In addition, there was no size change in the non-rDNA region as detected by NotI digestion of chromosome 2, and there was no observed change in the individual rDNA basic repeat unit size. From these lines of evidence, we confirmed that the clonal size variation of chromosome 2 which occurs at high frequency is derived from the size change of the rDNA cluster.

Candida albicans↗
PubMed1992

Significant compatibility does not exist at the HLA-DQB gene locus in couples with unexplained recurrent abortions.

The polymerase chain reaction-restricted fragment length polymorphism (PCR-RFLP) method was used for both examining compatibility at the HLA-DQB1 gene locus and determining HLA-DQ antigen polymorphism in spouses of unexplained recurrent abortions. Genomic DNA samples were prepared from peripheral mononuclear cells from patient and control couples. Two hundred and thirty base pair fragments of the second exon of the HLA-DQB genes were selectively amplified. Amplified DNAs were digested with the restriction endonucleases, Fok I, Hae III, Hha I, Rsa I and Sau3A I, and subjected to electrophoresis in a polyacrylamide gel. The RFLPs showed that habitual aborters and their husbands had neither significantly frequent alleles nor shared common alleles at the HLA-DQB locus when compared to the control group. Since significant HLA-DQB compatibility was not observed between the spouses and unexplained recurrent aborters, in order to determine whether or not HLA compatibility is responsible for the genesis of unexplained recurrent abortions, it is imperative to further examine the compatibility between other HLA gene loci.

Abortion, Habitual↗
PubMed1992

[Rapid diagnosis of cytomegalovirus pneumonia and Pneumocystis carinii pneumonia by using polymerase chain reaction DNA amplification].

We attempted to detect cytomegalovirus DNA (CMV-DNA) and Pneumocystis carinii DNA (carinii-DNA) in urine, blood and sputum samples of 16 leukemia patients with pneumonia, using the polymerase chain reaction (PCR). Synthetic oligonucleotide primer pair were used to amplify DNA from the major immediately genes of CMV and genes for the large subunit of mitochondrial ribosomal RNA of P. carinii. Amplified products were detected by gel electrophoresis. In two cases, CMV-DNA was detected at about the time the pneumonia occurred, and in one of the two cases, CMV-DNA was detected in the sputum sample. This patient was treated immediately with ganciclovir. After ganciclovir treatment, clinical and biochemical signs of CMV pneumonia disappeared. In three cases, carinii-DNA was detected in their sputum samples. In their blood and urine samples, carinii-DNA were not detected. This three cases were treated with sulfamethoxazole-trimethoprim and successfully treated episodes of P. carinii pneumonia. We conclude that PCR amplification may be a valuable tool for rapid diagnosing CMV pneumonia and P. carinii pneumonia.

Base Sequence↗
PubMed1992

Hepatocellular carcinoma: treatment with percutaneous ethanol injection and transcatheter arterial embolization.

The therapeutic effectiveness of a new combination therapy--pretreatment with transcatheter arterial embolization (TAE) and subsequent percutaneous ethanol injection (PEI)--for solitary large (> 3.0 cm in diameter) primary hepatocellular carcinoma lesions was compared with that of TAE alone. With TAE alone, a partial response of the tumor was seen in only 10% of the patients, and the 1-, 2-, and 3-year survival rates were calculated to be 68%, 37%, and 0%, respectively. Histologic examination of specimens obtained at hepatectomy showed that TAE alone caused complete necrosis in only 20% of the tumors. In contrast, PEI combined with TAE significantly (P < .05) increased the partial response rate (45%) and significantly (P < .01) prolonged the 1-, 2-, and 3-year survival rates (100%, 85%, and 85%, respectively). Combination therapy caused complete histologic necrosis in 83% of the tumors. It also was significantly (P < .05) better than TAE alone in terms of rate of primary tumor recurrence during follow-up.

Aged↗