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Biomedical subjects

M Shibata

Publications and source records attributed to M Shibata.

At least 523 records · Page 29Linked to original sources
PubMed1991

Microsurgical toenail transfer to the hand.

Free nonvascularized toenail grafts have been used to reconstruct congenital or traumatic nail defects of the thumb or finger. Unfortunately, these transfers often result in deformity or atrophy. To avoid these undesirable results, microsurgical free vascularized toenail transfer was performed in 10 patients, 3 for congenital nail absence and 7 for traumatic nail defects. Patient age averaged 17 years (range 2 to 32 years). In contrast with previous reports, the whole big or second toenail complex without pulp was used in reconstruction. All 10 nails were successfully transferred with complete survival. No digits required reexploration. There were no donor- or recipient-site problems. Follow-up averaged 3 years, with a range of 14 months to 5 years and 4 months. Appropriate nail growth occurred in the congenital patients. No atrophy of the nail complex was found as long as sufficient bony support was present (9 of 10 cases). Whole free vascularized toenail transfers for reconstruction of congenital and traumatic nailbed defects achieve excellent aesthetic results while maintaining normal hand function.

Adolescent↗
PubMed1990

Cerebral hemodynamics during cortical spreading depression in rabbits.

Effects of a single cortical spreading depression (CSD), elicited by KCl microinjection, on diameter of pial arterioles and venules in the parieto-occipital cortex were examined in urethane-anesthetized adult rabbits using a closed cranial window. The velocity of CSD propagation was 2.7 +/- 0.1 mm/min (mean +/- S.E.M.). All arterioles (n = 39) except for those in the retrosplenial region (n = 6) increased their diameter significantly during CSD. The arteriolar dilation lasted for 1.5 +/- 0.1 min. Location of dilating arteriole and propagating CSD showed that they were always closely associated temporally. As a percentage change, diameters of smaller arterioles significantly increased (from 60 +/- 1 to 103 +/- 2 microns, 71%, n = 12) more than those of larger ones (from 82 +/- 2 to 129 +/- 3 microns, 57%, n = 27). While venules with initial diameter of 85 +/- 4 microns (n = 5) did not dilate, those with initial diameter of 49 +/- 3 microns increased to 57 +/- 3 microns (16%, n = 8) for 1.4 +/- 0.2 min during CSD. The majority of the dilated venules started to increase their diameter after nearby arterioles had dilated maximally. Pial arterioles, which dilated during ipsilateral CSD, decreased their diameter significantly from 78 +/- 2 to 72 +/- 3 microns (8%, n = 11) during contralateral CSD for 13.8 +/- 3.6 min with similar onset latencies as those observed for the dilation. Indomethacin pretreatment significantly enhanced arteriolar dilation during CSD (from 73 +/- 4 to 138 +/- 6 microns, 89%, n = 4).(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia↗
PubMed1990

Human cytomegalovirus infection during childhood: detection of viral DNA in peripheral blood by means of polymerase chain reaction.

Polymerase chain reaction (PCR) technique was applied to detect cytomegalovirus (CMV) DNA. Two pairs of synthetic oligonucleotide primers were used to amplify DNA from the immediate early 1 and the late antigen genes of CMV, respectively. Either primer sets could detect as few as 0.01 plaque-forming unit of CMV strain AD 169 by Southern blot hybridization. Sixteen CMV clinical isolates were examined and all were found to be positive by the both primer sets. The PCR was used to detect CMV DNA in peripheral blood from six children with elevated anti-CMV antibody titers, who showed abnormal liver-function tests. In three immunocompromised patients, all blood samples were positive for CMV DNA. In three immunocompetent young infants with primary CMV infection, CMV DNA was detected from peripheral blood of one patient during acute phase. Presence of CMV DNA in peripheral blood seemed to be related with the extent of CMV infection, and possibly diagnostic for CMV hepatitis.

Child, Preschool↗
PubMed1990

Detection and direct typing of herpes simplex virus by polymerase chain reaction.

A method for the detection and direct typing of herpes simplex virus (HSV) by the polymerase chain reaction (PCR) technique has been developed. One common upstream primer and two type-specific downstream primers were prepared to amplify DNA from the HSV type 1 and type 2 DNA polymerase gene. Using these three primers simultaneously in the PCR reaction mixtures, both types of HSV DNA were amplified to produce products of different sizes. By direct gel analysis, the products of standard HSV type 1 and type 2 strains had the predictive sizes of 469 and 391 base pairs, respectively, and the difference in molecular mass enabled us to type the HSV strain. A total of 24 strains (type 1; 16 and type 2; 8 strains) were examined by PCR, and the results were consistent with those determined by immunofluorescence using type-specific monoclonal antibodies. No specific amplification was observed using other herpes virus or human genomic DNAs. The PCR method was then applied to clinical specimens. Of 15 samples obtained from oral lesions of children with herpetic gingivostomatitis, all (100%) were HSV positive by PCR, compared with 13 (86.7%) using standard cell culture methods. Three specimens from vulvar lesions of women with genital herpes were positive using both PCR and cell cultures. There was complete agreement in the typing of HSV strains using the PCR method or virus isolation. On the basis of these results, it is suggested that DNA amplification and typing by PCR is particularly useful for material from which virus isolation might be difficult.

Animals↗
PubMed1990

ATP-independent strand transfer protein from murine spermatocytes, spermatids, and spermatozoa.

A protein-catalyzing D-loop formation is present in murine spermatocytes, spermatids, and spermatozoa, but is not found in somatic tissue or in premeiotic cells of the germline. Unlike the Escherichia coli RecA protein and the meiotic rec protein (m-rec) previously described, D-loop formation by this protein (referred to as "mAi-rec") does not require ATP. The meiotic profile of mAi-rec activity is only partly similar to that of m-rec. Like m-rec, it rises steeply during early prophase and reaches a peak at pachytene. Unlike m-rec, its activity remains high during the postmeiotic phase of spermatid development and is prominent in immunochemically stained spermatozoa. A polyclonal antibody to E. coli RecA reacts with mAi-rec and inhibits its activity. No such reaction occurs with m-rec protein. The extent of sequence homology between E. coli RecA and murine mAi-rec is highly limited; none of the several monoclonal antibodies tested reacted with mAi-rec.

Adenosine Triphosphate↗
PubMed1990

The efficiency of the vascular-tissue system for oxygen transport in the skeletal muscles.

The efficiency of the vascular-tissue system for oxygen (O2) transport in the skeletal muscle was estimated by using Krogh's cylinder model for the capillary-tissue arrangement. The tissue mass supplied by a single capillary was calculated as the region of positive O2 tension. For given values of total muscle flow and tissue O2 consumption rate, total tissue mass was determined as the function of the capillary number (n). The energy cost to maintain the vascular system with n terminals (capillaries) was assessed by the minimum volume model by Kamiya and Togawa (1972). The efficiency of the entire system was evaluated by calculating the ratio of (total tissue mass) or (total O2 consumption)/(the energy cost). The results of the calculation using physiological data of muscle blood flow and O2 consumption rate in man during exercise revealed the optimum capillary number to be around 1.5 x 10(10) and the Krogh cylinder radius to be 26 microns, which agrees well with the morphological data of these values in human skeletal muscles. It was concluded that the vascular-tissue system in the skeletal muscle is constructed so as to attain the highest efficiency in O2 transport to tissue during exercise.

Animals↗
PubMed1990

Glucose-stimulated phosphorylation of the 64-kDa protein of human polymorphonuclear leukocytes in a cell-free system.

Glucose-stimulated phosphorylation of 64-kDa protein using a greater than 30 kDa fraction of human polymorphonuclear leukocytes in a dose-dependent fashion with 33 microM for maximum stimulation and 1.4 microM for ED50. None of the glucose derivatives and metabolites of glycolysis stimulated phosphorylation, but glucose-1-phosphate, glucose-6-phosphate, fructose-6-phosphate and fructose-1,6-diphosphate inhibited the glucose-stimulated phosphorylation, strongly suggesting phosphorylation by glucose-regulated protein kinase. Cyclic nucleotides and the protein kinase inhibitors H-7, H-8, W-7 and staurosporine did not affect phosphorylation.

Cell-Free System↗
PubMed1990

Expression of bovine cytochrome P450c21 and its fused enzymes with yeast NADPH-cytochrome P450 reductase in Saccharomyces cerevisiae.

Recombinant plasmids for expression of bovine cytochrome P450c21 (pA gamma 2), both P450c21 and yeast NADPH-cytochrome P450 reductase (pAR gamma 1), P450c21/yeast reductase fused enzymes (pAF gamma R1, pAF gamma R2, and pAF gamma R20), and yeast reductase/P450c21 fused enzymes (pAFR gamma 1 and pAFR gamma 2) were constructed by using expression vector pAAH5. The plasmids were each introduced into the yeast Saccharomyces cerevisiae AH22 cells. The recombinant yeast strains AH22/pA gamma 2 (Y21) and AH22/pAR gamma 1 (Y21R) produced 2-3 X 10(3) molecules of P450c21 per cell. The cultures of both strains converted progesterone and 17 alpha-hydroxyprogesterone into 11-deoxycorticosterone and 11-deoxycortisol, respectively. The 21-hydroxylase activity per cell of the strain Y21R was about three times higher than that of the strain Y21, probably due to overproduction of yeast reductase. The recombinant yeast strains AH22/pAF gamma R1 (Y21RF1), AH22/pAF gamma R2 (Y21RF2), and AH22/pAF gamma R20 (Y21RF20) produced about 1.1-2.0 X 10(4) molecules per cell of the corresponding P450c21/yeast reductase fused enzymes. The specific 21-hydroxylase activity toward 17 alpha-hydroxyprogesterone per cell of the strains Y21RF1, Y21RF2, and Y21RF20 was about 21, 28, and 49 times higher than that of the strain Y21, respectively. Thus, the fused enzymes were superior to P450c21 in the specific activity and in the expression level in the yeast. The Km values for 17 alpha-hydroxyprogesterone of P450c21 in the strains Y21 and Y21R, and of the fused enzymes in the strains Y21RF1 and Y21RF2 were 0.29, 0.30, 0.67, and 0.65 microM, respectively. The Vmax values of P450c21 in the strains Y21 and Y21R, and of the fused enzymes in the strains Y21RF1 and Y21RF2 were 28, 124, 151, and 222 moles/min.mole P450c21 or fused enzyme, respectively. These results indicated that the fused enzymes showed lower affinity for the substrate, probably due to structural modification and higher reaction rates through efficient intramolecular electron transfer as compared with those of P450c21. While the strain AH22/pAFR gamma 2 (YR21F2) produced about 3 X 10(4) molecules per cell of the reductase/P450c21 fused enzyme, the specific 21-hydroxylase activity of the fused enzyme toward 17 alpha-hydroxyprogesterone was extremely low, suggesting that the structure of the fused enzyme might not be suited for electron transfer in yeast microsomes.

17-alpha-Hydroxyprogesterone↗
PubMed1990

Expression of cloned yeast NADPH-cytochrome P450 reductase gene in Saccharomyces cerevisiae.

The NADPH-cytochrome P450 reductase gene isolated from the yeast Saccharomyces cerevisiae [Yabusaki et al., J. Biochem. 103, 1004-1010 (1988)] was expressed on a multi-copy plasmid in the yeast. The transformed yeast cells with the recombinant plasmid carrying the reductase gene with a length of 3 kb produced the corresponding mRNA read from the original transcription initiation site under the control of its own promoter with a maximum length of 300 bp. The reductase content in the transformed cells was 25 times higher than that of the endogenous reductase. When the coding region for the reductase was placed between the alcohol dehydrogenase I gene promoter and the terminator of the expression vector pAAH5, the expression level was 32 times higher than at the endogenous level. These recombinant yeast strains showed enhanced cytochrome c reductase activity with increased cellular reductase levels. A simultaneous expression of yeast P450 reductase with rat P450c or bovine P450(17 alpha) resulted in 25 times or a 5 times increase in the corresponding P450-dependent monooxygenase activity of the recombinant yeast strains, respectively, as compared with that of the yeast cells expressing the corresponding P450 species. These results suggested that the overproduction of yeast P450 reductase with a simultaneous expression of the mammalian P450 species enhanced the P450c- and P450(17 alpha)-dependent monooxygenase activities in the recombinant yeast strains, probably due to the increased frequency of the interaction between yeast P450 reductase and P450c or P450(17 alpha) in the yeast microsomes.

Alcohol Dehydrogenase↗
PubMed1990

Structure-activity relations in promotion of rat urinary bladder carcinogenesis by phenolic antioxidants.

The urinary bladder tumor-promoting potentials of the phenolic antioxidants, 2-tert-butyl-4-methylphenol (TBMP), propylparaben, catechol, resorcinol and hydroquinone, which are structurally related to butylated hydroxyanisole (BHA), were investigated in 170 male F344 rats. The animals were initially given 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) as an initiator in their drinking water for 4 weeks. Three days later, groups of 20 rats received diet containing 1.0% TBMP, 3% propylparaben, 0.8% catechol, 0.8% resorcinol, 0.8% hydroquinone or basal diet alone until the end of week 36. Significant increases in the incidences and average numbers of the putative preneoplastic lesions, papillary or nodular (PN) hyperplasia, and papillomas of the urinary bladder were only observed in the group given TBMP after BBN. Development of these lesions was not enhanced by diet containing the other test compounds and no induction was associated with any of the test chemicals alone. The results thus clearly showed that TBMP, which most closely resembles BHA, promoted urinary bladder carcinogenesis. The similar effects of TBMP and BHA on urinary bladder carcinogenesis suggest a direct link between chemical structure and biological potency.

Animals↗
PubMed1990

Cloning and nucleotide sequence of cDNA for Ki antigen, a highly conserved nuclear protein detected with sera from patients with systemic lupus erythematosus.

Patients with systemic lupus erythematosus (SLE) produce autoantibodies against a variety of nuclear antigens including Ki antigen. Although anti-Ki autoantibodies were found in a significant number of SLE patients, the nature of Ki antigen is poorly characterized. By using anti-Ki serum as a probe we have cloned a bovine cDNA directing the synthesis in Escherichia coli of a polypeptide immunologically indistinguishable from the authentic Ki antigen. A homologous human cDNA was also cloned and its nucleotide sequence predicted the entire primary structure of a novel nuclear protein with a molecular weight of 29 508 and with highly hydrophilic and weakly acidic character. The gene is highly conserved not only in the coding region but also in the 3'-untranslated region. The bacterially produced Ki antigen would be valuable for diagnosis of SLE.

Amino Acid Sequence↗
PubMed1990

Recombinant human interleukin 1 alpha dilates pial arterioles and increases cerebrospinal fluid prostanoids in piglets.

Effects of recombinant human interleukin 1 alpha (IL-1 alpha) on vasomotor tone of pial arterioles and cerebrospinal fluid (CSF) prostanoid levels were examined in anesthetized piglets by employing the closed cranial window method. IL-1 alpha in a dose of 10.8 micrograms infused under the window increased pial arteriolar diameter [initial size, 160 +/- 9 (SE) micrograms] significantly at 15 min postinfusion through 30 min (30-min study), exhibiting a maximum dilation of 13 +/- 1% (n = 8) over the control levels. Significant increases in levels of prostaglandin E2 (PGE2, 75%), 6-keto-PGF1 alpha (84%), and PGF2 alpha (35%) but not for thromboxane B2 (TxB2, 2%) were observed when CSF was sampled from under the window 30 min after 10.8 micrograms IL-1 alpha. A lower dose of IL-1 alpha (1.0 micrograms, n = 4) significantly increased the diameter of pial arterioles with a tendency for longer onset (25-30 min) and smaller magnitude (9-10%) than the higher dose. In IL-1 alpha time-response studies, CSF sampled 10 min after 10.8 micrograms IL-1 alpha infusion (10-min study, n = 6) under the window exhibited the same levels of PGE2, 6-keto-PGF1 alpha, PGF2 alpha, and TxB2 as those of the controls. There was no vasodilation in the 10-min study. However, when sampled 20 min after 10.8 micrograms IL-1 alpha (20-min study, n = 6), CSF levels of all prostanoids except for TxB2 significantly increased over the controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗