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Biomedical subjects

Y Hidaka

Publications and source records attributed to Y Hidaka.

At least 163 records · Page 9Linked to original sources
PubMed1991

Evaluation of a filtration lymphocytapheresis (LCP) device for use in the treatment of patients with rheumatoid arthritis.

A practical on-line lymphocytapheresis (LCP) system using a leukapheresis filter (Cellsorba, Asahi Medical Co.) was evaluated in six patients with refractory rheumatoid arthritis. This filter consists of nonwoven fine polyester fiber wound around a porous cylinder. The blood was passed through the polyester fiber at a flow rate of 50 ml/min for 60 min. LCP was carried out once a week in the first month and biweekly in the next 2 months. An average of 98% of the leukocytes that entered the filter (1.27 x 10(10) cells) and 100% of the lymphocytes that entered the filter (3.66 x 10(9) cells) were removed in the first LCP. A total of 96.6% of the platelets and 2.7% of the erythrocytes that entered the filter were also removed. All of the patients showed clinical improvement in morning stiffness, Lansbury articular index, and functional capacity, with no adverse reaction. The number of circulating erythrocytes and platelets and the concentration of various serum components showed no significant change during the treatments. This LCP system required no fresh frozen plasma, albumin, or other blood transfusion. The number of circulating lymphocytes decreased to 65-70% of the pretreatment circulating lymphocyte count at the last procedure, with a decrease in the ratio of Leu3a positive cells to Leu2a positive cells. The proliferative response to phytohemagglutinin and concanavalin A was improved. These data suggest that LCP to remove approximately 3 x 10(9) lymphocytes once a week or biweekly has an immunomodulatory effect.

Arthritis, Rheumatoid↗
PubMed1991

Environmental differences of a pyridine derivative (AU-1421)-access sites between (H+,K+)-ATPase and (Na+,K+)-ATPase.

We investigated the environmental differences of a pyridine derivative-access sites between hog gastric (H+,K+)-ATPase and dog kidney (Na+,K+)-ATPase. The environmental differences are inferred from the marked contrasts in inhibition properties of (Z)-5-methyl-2-[2-(1-naphthyl)ethenyl]-4-piperidinopyridine hydrochloride (AU-1421) between the two adenosine triphosphatases (ATPases). AU-1421 is a hydrophobic pyridine derivative which inhibits (H+,K+)-ATPase and (Na+,K+)-ATPase competitively with respect to K+. AU-1421 inhibition of (Na+,K+)-ATPase activity is preincubation time-dependent, pH-independent (pH 6.4-8.4), and hardly reversible by dialysis. These features are opposite to those found with the gastric (H+,K+)-ATPase. Furthermore, in the presence of dilute sodium dodecyl sulfate (30-120 microM), the inhibitory potency of AU-1421 for (Na+,K+)-ATPase is increased, whereas the inhibitory potency for (H+,K+)-ATPase is decreased. These results favor proposals that protonated species of AU-1421 interact with its access-site of (H+,K+)-ATPase at the exterior surface of the enzyme molecule by ionic interaction, whereas AU-1421 interacts with its access-site of (NA+,K+)-ATPase at the interior domain of the enzyme molecule predominantly by hydrophobic interaction. The differences indicate the existence of a different feature of K(+)-access sites between the two ATPases.

Adenosine Triphosphatases↗
PubMed1991

[Effect of plasma on analysis of lymphocyte subsets].

We examined the effect of plasma on the analysis of lymphocyte subsets with a flow cytometer using whole blood cells. Removal of plasma from whole blood by washing them before labelling the lymphocytes with fluorescein-conjugated antibodies reduced the proportion of CD5+CD19+ cells and increased the proportions of CD16+ CD57- and CD16+ CD57+ cells, as compared with those measured without washing, but did not change the proportions of CD5+ CD19-, CD5- CD19+, CD4+ CD8-, CD4- CD8+ and CD16- CD57+ cells. Removal of plasma from whole blood also reduced the fluorescence intensity of CD4 and CD5 antigens and increased that of CD8, CD16, CD19 and CD57 antigens on each lymphocyte subsets. Characteristics of the changed lymphocyte subsets were to have a surface antigen with weak immunofluorescence on the flow cytometric analysis such as CD5 and CD16, and to have an unclear borderline between the positive and negative cells. Therefore, even slight changes in the fluorescence intensity of these antigens could change the proportion of CD5+ CD19+, CD16+ CD57- and CD16+ CD57+ cells. However, these changes were not observed, when using the washed blood cells as samples after readdition of plasma to them. These data suggest that removal of plasma from blood before labelling the lymphocytes with fluorescein-conjugated antibodies is necessary to make the sample condition equal for flow cytometric analysis of lymphocyte subsets.

Adult↗
PubMed1991

[A case of bilateral Bochdalek hernia in an adult].

A 71-year-old male was found to have bilateral posteromedial masses on routine roentgenogram during admission for treatment of traffic accident related injuries. These masses were initially considered to be posterior mediastinal tumors, however, CT scan demonstrated a left diaphragmatic defect and the adipose nature of the bilateral masses (CT number: left -29, right -132). MRI also demonstrated a large amount of fat accumulation in the abdomen. CT scan and MRI are therefore very useful for the diagnosis of Bochdalek hernia in adults.

Aged↗
PubMed1991

A mutant allele common to the type I adenine phosphoribosyltransferase deficiency in Japanese subjects.

Adenine phosphoribosyltransferase (APRT) deficiency is a genetic disorder which causes 2,8-dihydroxy-adenine urolithiasis. The estimated incidence of heterozygosity in Caucasian and Japanese populations is 1%. Mutant alleles responsible for the disease have been classified as APRT*Q0 (type I) and APRT* (type II). In our previous study, we demonstrated in APRT*J a single common base change which accounts for 70% of the Japanese mutants. The present report describes the analysis of an APRT*Q0 mutation in Japanese subjects. Two nucleotide substitutions common to all seven affected alleles from four unrelated subjects (three homozygotes and a heterozygote) were identified: G----A at nucleotide position 1453 and C----T at 1456. The G----A altered the amino acid Trp98 to a stop codon. The C----T did not alter Ala99. These point mutations were demonstrated by sequence analysis of polymerase chain reaction (PCR)-amplified genomic DNA and cDNA. The G----A change at 1453 results in the elimination of a PflMI site in the APRT gene. PflMI digests, which were used to confirm the G----A transition, can be useful in screening for this specific mutation.

Adenine Phosphoribosyltransferase↗
PubMed1990

Effect of simvastatin (MK-733) on the regulation of cholesterol synthesis in Hep G2 cells.

A new antihypercholesterolemic drug, simvastatin (MK-733), which is a prodrug of a potent 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, inhibited cholesterol synthesis from [14C]acetate concentration dependently without inhibiting it from [3H]mevalonate in Hep G2 cells. Therefore, MK-733 is thought to be converted to L-654,969, the active beta-hydroxy acid form of MK-733 in the cells and/or medium. MK-733 inhibited cholesterol ester synthesis, but did not affect phospholipid, free fatty acid and triacylglycerol synthesis. This compound increased HMG-CoA reductase activity concentration dependently and raised the specific binding, internalization and degradation of 125I-labeled low density lipoprotein by Hep G2 cells. Another HMG-CoA reductase inhibitor, pravastatin (CS-514), also behaved like MK-733. However, its potency was far less than that of MK-733.

Anticholesteremic Agents↗
PubMed1990

Disulfide pairings in geographutoxin I, a peptide neurotoxin from Conus geographus.

The three intramolecular disulfide linkages of geographutoxin I, a peptide neurotoxin isolated from the venom of the marine snail Conus geographus, were examined by a novel method for determination of the positions of disulfide linkages in peptides [(1989) Bull. Chem. Soc. Jp. 62, 1986-1994]. The disulfide bridges were found to be between Cys3 and Cys15, Cys4 and Cys20, and Cys21, indicating that geographutoxin I has a rigid conformation consisting of three loops stabilized by these three disulfide linkages.

Amino Acid Sequence↗
PubMed1990

Crossovers within a short DNA sequence indicate a long evolutionary history of the APRT*J mutation.

Adenine phosphoribosyltransferase (APRT) deficiency causing 2,8-dihydroxyadenine urolithiasis and renal failure is present at a high frequency among the Japanese but not other ethnic groups. A special type of mutant allele, designated APRT*J, with a nucleotide substitution at codon 136 from ATG (Met) to ACG (Thr) is carried by approximately 79% of all Japanese 2,8-dihydroxyadenine urolithiasis patients. We analyzed mutant alleles of 39 APRT deficient patients using a specific oligonucleotide hybridization method after in vitro amplification of a part of the genomic APRT sequence. We found that 24 had only APRT*J alleles. Determination of the haplotypes of 194 APRT alleles from control Japanese subjects and of the 48 different APRT*J alleles indicated that normal alleles occur in four major haplotypes, whereas all APRT*J alleles occur in only two. These results suggest that all APRT*J alleles have a single origin and that this mutant sequence has been maintained for a long period, as calculated from the frequency of the recombinant alleles.

Adenine Phosphoribosyltransferase↗
PubMed1990

Characterization of glycoprotein C-negative mutants of herpes simplex virus type 1 isolated from a patient with keratitis.

Recently three strains of herpes simplex virus type 1 (HSV-1), which did not react with Micro Trak Herpes (Syva Co.), were isolated by us from a patient with recurrent herpetic keratitis. In this study we characterized these strains of HSV-1 and found them to be HSV-1 gC- mutants which are very rare isolates from humans. The properties of the HSV-1 strains regarding plaque morphology on Vero cells and chick embryo fibroblasts and viral DNA analysis were the same as those of the usual HSV-1 strains. An immunofluorescence study using anti-gC-1 monoclonal antibody and SDS-PAGE analysis of radiolabeled viral glycoproteins showed that these strains are deficient in gC-1. They were virulent for mice and sensitive to acyclovir and bromovinyldeoxyuridine. Furthermore the infectivity of the strains was inactivated by complement though the phenomenon was not observed in the usual HSV-1 strains. This finding suggests that protection from damages by complement is an important function of gC. In keratitis the effects of complement are thought to be minimal because of the scanty blood supply and this may be the reason why these strains were isolated from the cornea.

Adult↗
PubMed1990

Seroepidemiology of herpes simplex virus type 1 in Yanji, Jilin, China.

Sera from 158 individuals in Yanji, Jilin, China, were tested for antibodies to herpes simplex virus type 1 (HSV-1) by the passive hemagglutination method. Age-specific incidence rates for antibodies to HSV-1 were calculated. For sera from persons in the age group 10 years or less, the positive rate was 54% but in the age group higher than 10 years, it was more than 91% (P less than 0.01). In the part of China surveyed, primary HSV-1 infection occurred in early generation before about age 10. In children, the positive rate in the Han race was significantly higher than that in the Korean race (P less than 0.05).

Adolescent↗