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Biomedical subjects

T Yamazaki

Publications and source records attributed to T Yamazaki.

At least 397 records · Page 22Linked to original sources
PubMed1996

Management and ultrasonographic appearance of infantile hypertrophic pyloric stenosis with intravenous atropine sulfate.

Some infants with hypertrophic pyloric stenosis (HPS) have responded to oral atropine treatment. To achieve sufficient effect of atropine, it must be administered intravenously (i.v.). Therefore, with ultrasonography, we studied the changes in the pyloric muscle in HPS during and after intravenous administration of atropine. Twenty-three infants were studied. Atropine sulfate was initially administered at a dose of 0.04 mg/kg day i.v., and the dose was increased by 0.01 mg/kg/day until vomiting ceased. When vomiting ceased after administration of intravenous atropine sulfate, the infants received oral atropine sulfate at twice the effective intravenous dose; this was continued for 2 weeks. Ultrasonography was repeated until pyloric muscles normalized. Twenty-two infants were free from vomiting after 1-8 days of intravenous atropine sulfate (dosages of 0.04-0.11 mg/kg/day). In 21 infants, weight gain continued after atropine treatment even though no change in thickness of the pyloric muscles was demonstrated ultrasonographically. Only 2 infants required pyloromyotomy because of prolonged treatment or a mistake in underdosing of oral atropine. All of the 21 infants who recovered after intravenous atropine without surgery had normalization of pyloric muscle caliber, as shown by ultrasonography 4-12 months after treatment. Atropine is an effective medicine for HPS. Regression of pyloric thickening after vomiting has been controlled implies that pyloric muscle hypertrophy could be worsened by the spasm that occurs in HPS.

Administration, Oral↗
PubMed1996

Angiotensin converting enzyme polymorphism is associated with severity of coronary heart disease and serum lipids (total cholesterol and triglycerides levels) in Japanese patients.

BACKGROUND: Much past research has concerned the relationship between coronary heart disease and the angiotensin converting enzyme (ACE) genotype, with many lines of evidence demonstrating polymorphism to be an independent risk factor for myocardial infarction. Interestingly, however, association of ACE polymorphism and severity of coronary artery stenosis according to racial background has recently been proposed. OBJECTIVE: To clarify the relationship between the ACE genotype and severity of coronary artery stenosis in Japanese patients. METHODS: In 36 consecutive patients undergoing coronary catheterization, comparative examination of coronary angiography findings with the ACE genotype was conducted. RESULTS: The severity of coronary artery stenosis indeed showed a relationship with the ACE genotype, with more severe coronary artery stenosis associated with the deletion (D) allele (P < 0.05). The serum lipids, total cholesterol and triglycerides levels, were also elevated in patients with the D allele (P < 0.05). CONCLUSION: We have provided further evidence that ACE polymorphism is associated with severity of coronary heart disease in a Japanese population. A possible relationship between serum lipids and the ACE genotype is also suggested.

Biomarkers↗
PubMed1996

Mature teratoma of the placenta.

A rare case of a mature teratoma of the placenta is reported. The tumor lay between the amnion and the chorion and contained skin and its appendages, bone, cartilage, fat and ganglia, without organization. There was no evidence of a recognizable umbilical cord. We concluded that the tumor was a mature teratoma of the placenta. The distinction between a teratoma and a fetus acardius amorphus, and the possible origin of the tumor in this site, are discussed with a brief review of the literature.

Adult↗
PubMed1996

[Assay of specific anti-Chlamydia pneumoniae antibodies by ELISA method. 2. studies on clinical usefulness and serological diagnostic standards].

We measured anti-Chlamydia pneumoniae (C. pneumoniae) specific antibody titers by means of a newly-developed enzyme-linked immunosorbent assay (ELISA) method using an anti-C. pneumoniae specific antibody detection reagent. The clinical usefulness of this method was hereby evaluated. The IgG, IgA and IgM titers in 418 serum specimens obtained from patients with respiratory tract infections were measured by this new ELISA method, and the results were compared with the titers determined for the same specimens with the micro immunofluorescence (Micro-IF) method. The results showed good correlation coefficients for IgG, IgA and IgM. The two assay methods showed high agreement rates for positivity and for negativity. Specimens which did not yield the same results with the ELISA method and the Micro-IF method were subjected to analysis by the Western blot method, and the rates of agreement with the ELISA results were high. In addition, the child (0 approximately 15 yrs old; n = 122) and adult (16 approximately 90 yrs old; n = 133) cases were classified on the basis of being antigen-positive or antigen-negative at the initial examination, and their antibody-positive rates were determined. The adults showed no statistically significant differences in the antibody-positive rates for either IgG or IgA antibodies as a function of the pretreatment antigen status. However, the children showed statistically significant (p < 0.001) differences in the antibody-positive rates for both IgG and IgA antibodies as a function of the antigen status in the antigen-positive group compared with the rates in the antigen-negative group. Furthermore, the IgM-positive rates for the children were high in the antigen-positive group compared with the rates in the antigen-negative group, and the difference was statistically significant (p < 0.001). The IgM-positive rates in the adults were also significantly (p < 0.05) different between the antigen-positive group and the antigen-negative group. The Micro-IF method was applied to 34 specimens from antigen-positive patients, and 22 specimens were found to show an IgG titer of > or = 512 or an IgM titer of > or = 16. The diagnoses of these patients were acute respiratory disease in sixteen, pneumonia in four. Application of the ELISA-method to those 22 specimens showed all of them to exhibit IgG absorbance of > or = 0.6 and IgA absorbance of 0.2. The results described above indicate the clinical usefulness of our new ELISA method for the detection of antibodies specific for C. pneumoniae. The significance of this ELISA method for serological diagnosis of C. pneumoniae infections and the criteria for diagnosis of acute infections were also discussed.

Adolescent↗
PubMed1996

Regional myocardial interstitial norepinephrine kinetics during coronary occlusion and reperfusion.

We investigated myocardial interstitial norepinephrine kinetics in both the ischemic and nonischemic regions during reperfusion after 40 min of coronary occlusion in anesthetized cats. By use of a cardiac dialysis technique, dialysate norepinephrine contents from both regions were monitored as an index of myocardial interstitial norepinephrine levels. For vehicle perfusate (n = 8), the accumulated dialysate norepinephrine level in the postischemic region decreased from 3,010 +/- 923 pg/ml at 30-40 min of occlusion to 957 +/- 178 pg/ml at 0-10 min of reperfusion and returned to near control level at 30-40 min of reperfusion. After 40 min of reperfusion, there were no significant differences in tyramine (100 micrograms/ml, norepinephrine-releasing sympathomimetic amine)-induced norepinephrine release between both regions. For perfusate containing 100 microM desipramine (neural uptake inhibitor, n = 6), at 0-10 min of reperfusion, the dialysate norepinephrine in the postischemic region did not significantly decrease. The dialysate norepinephrine then returned to near preocclusion level at 30-40 min of reperfusion. These data suggest that reperfusion rapidly returns accumulated myocardial norepinephrine to the preischemic level and neuronal norepinephrine uptake greatly contributes to this return in the early phase of reperfusion. Forty minutes of coronary occlusion cause neither norepinephrine exhaustion nor irreversible impairment of norepinephrine uptake function in nerve terminals.

Animals↗
PubMed1996

Bidirectional augmentation of heart rate regulation by autonomic nervous system in rabbits.

Although the characteristics of the static interaction between the sympathetic and parasympathetic nervous systems in regulating heart rate (HR) have been well established, how the dynamic interaction modulates the HR response remains unknown. We therefore investigated dynamic interaction by estimating the transfer function from nerve stimulation to HR using a band-limited Gaussian white-noise technique. The transfer function relating dynamic sympathetic stimulation to HR had characteristics of a second-order low-pass filter. Simultaneous tonic vagal stimulation at 5 and 10 Hz increased gain of the transfer function by 55.0 +/- 40.1 and 80.7 +/- 50.5%, respectively (P < 0.05). The transfer function from dynamic vagal stimulation to HR had characteristics of a first-order low-pass filter. Simultaneous tonic sympathetic stimulation at 5 and 10 Hz increased the gain by 18.2 +/- 17.9 and 24.1 +/- 18.0%, respectively (P < 0.05). Thus interaction augmented dynamic gain bidirectionally, even though it affected mean HR antagonistically. By virtue of this interaction, the autonomic nervous system appears to extend its dynamic range of operation.

Animals↗
PubMed1996

Molecular cloning and characterization of human cardiac homeobox gene CSX1.

Accumulating evidence has suggested that homeo-domain-containing proteins play critical roles in regulating the tissue-specific gene expression essential for tissue differentiation and in determining the temporal and spatial patterns of development. In order to elucidate the mechanisms of human heart development, we have isolated a human homologue of the murine cardiac homeobox gene Csx (also called Nkx-2.5) and denoted it as CSX1. The amino acid sequence of the CSX1 homeodomain is 100% and 67% identical to that of murine Csx/Nkx-2.5 and Drosophila tinman, respectively. CSX1 has at least three isoforms generated by an alternative splicing mechanism. One of these isoforms (CSX1a) encodes a protein of approximately 35 kD that possesses the homeodomain, whereas the other two (CSX1b and CSX1c) encode a truncated protein of approximately 12 kD that is identical to the CSX1a protein at the amino-terminal 112 amino acids but lacks the homeodomain. Northern blot analysis showed that CSX1 transcripts are abundantly expressed in both fetal and adult hearts, but no signal was detected in other human tissues examined. Amplification of each isoform by reverse transcriptase-polymerase chain reaction revealed that all of the three isoforms are expressed in fetal and adult hearts and that the homeobox-containing isoform CSX1a is most abundant. The homeodomain-containing protein encoded by CSX1a binds to Csx/Nkx-2.5 binding sequences and transactivates the sequence-containing luciferase reporter gene. Unexpectedly, the homeodomain-lacking protein encoded by CSX1b also transactivates the reporter gene, although CSX1b does not bind to the Csx/Nkx-2.5 binding sequences. The highly conserved homeodomain sequence in evolution and the restricted expression in the heart suggest that CSX1 plays an important role in the development and differentiation of the human heart and that there may be two different mechanisms in transcriptional regulation by the CSX1 protein, homeodomain-dependent and -independent mechanisms.

Base Sequence↗
PubMed1996

15-lipoxygenase metabolite(s) of arachidonic acid mediates adrenocorticotropin action in bovine adrenal steroidogenesis.

The acute activation of adrenal glucocorticoid synthesis by ACTH has long been believed to be mediated by cAMP as the major second messenger, although increases in cellular cAMP concentration have not been observed at low concentrations of ACTH. We found that steroidogenesis in bovine adrenal fasciculata-reticularis cells was activated by the addition of arachidonic acid or its 15-lipoxygenase metabolite, 15-hydroperoxyeicosatetraenoic acid. The cellular 15-lipoxygenase pathway was significantly activated by 1 pM ACTH, at which concentration no increase in cellular cAMP synthesis was observed. The 1 pM ACTH-induced stimulation of steroidogenesis was completely suppressed by a lipoxygenase inhibitor, AA-861. The stimulation was independent of the increase in cellular cAMP. These results show that the action of 1 pM ACTH on steroidogenesis may be mediated by the 15-lipoxygenase metabolite(s) as a solo second messenger. The addition of ACTH at concentrations higher than 10 pM increased both the 15-lipoxygenase activity and cellular cAMP synthesis. Under these conditions, the 15-lipoxygenase metabolite(s) and cAMP were shown to mediate the activation of steroidogenesis synergistically. The presence of a dual second messenger system could explain the stimulation of steroidogenesis by ACTH at physiological concentrations.

Animals↗
PubMed1996

Trafficking of cell-surface amyloid beta-protein precursor. II. Endocytosis, recycling and lysosomal targeting detected by immunolocalization.

Amyloid beta-protein (A beta) is a proteolytic fragment of the amyloid beta-protein precursor (beta PP). Progressive cerebral deposition of A beta is an early and invariant feature of Alzheimer's disease. The cellular trafficking of beta PP is of particular interest because understanding the production of A beta requires a comprehensive elucidation of the metabolic pathways of this protein. In addition, beta PP is a type I integral membrane glycoprotein that belongs to a class of molecules with both full length and secreted products. Recent evidence suggests that beta PP can be processed in an endosomal/lysosomal pathway. In the latter organelles, a number of beta PP carboxy-terminal derivatives are found, but the precise pathway and kinetics of beta PP trafficking from the cell surface remain unclear. To address these questions, we visualized directly the beta PP internalization pathway by following the localization and distribution of beta PP monoclonal antibodies added to intact beta PP-transfected Chinese hamster ovary cells. Using immunofluorescence and immunoelectron microscopy, beta PP was shown to be rapidly internalized via coated pits and vesicles, after which the molecules were transported to endosomes, prelysosomes, and lysosomes. Using a modified immunodetection protocol, we demonstrated the rapid recycling of endocytosed beta PP to the cell surface and its ultimate targeting to lysosomes. Because we recently found that endocytosis of cell surface beta PP is one route for the constitutive production of A beta, the recycling pathway for cell surface beta PP demonstrated here is a probable route for production of the critical A beta fragment.

Amyloid beta-Protein Precursor↗
PubMed1996

Bacillus stearothermophilus cell shape determinant gene, mreC and mreD, and their stimulation of protease production in Bacillus subtilis.

Protease production stimulating genes were isolated from a soybean protein degrading bacterium, Bacillus stearothermophilus HA19. The cloned fragment stimulated production of a 37-kDa protease in B. subtilis. The nucleotide sequence of the genes and their flanking regions were identical to the B. subtilis cell shape determinant genes mreC and mreD [J. Bacteriol., 176, 6729-6742 (1992); J. Bacteriol., 176, 6717-6728 (1992)]. The mreC and mreD genes in B. subtilis stimulate secretion of a neutral protease (37-kDa), and the protease activity in the culture medium reached 2500 U per ml (approximately 10 times higher than the host strain) after 24 h of cultivation in L broth, suggesting the mreCD genes regulate protease expression and the protease is related to the cell shape determination in Bacilli. The protease productions in B. subtilis carrying mreC or mreD deletion plasmids were not elevated, so the 37-kDa protease stimulation requires both mreC and mreD genes. The extracellular protease was purified, and the molecular mass of the enzyme was 37,000 Da by SDS-polyacrylamide gel electrophoresis and gel filtration. The optimum pH and temperature for the enzyme activity were 7.0 and 50 degrees C, respectively, and the enzyme was stable at pH 7-10. The enzyme was inactivated by EDTA, but not by phenylmethyl sulfonyl fluoride and diisopropyl fluorophosphate.

Amino Acid Sequence↗
PubMed1996

The integrative transformation of Pleurotus ostreatus using bialaphos resistance as a dominant selectable marker.

A plasmid pLC-bar containing the bialaphos resistance gene derived from Streptomyces hygroscopicus between the Lentinus edodes ras gene promoter and priA gene terminator was constructed. When protoplasts of Pleurotus ostreatus were mixed with the plasmid DNA in the presence of polyethylene glycol and CaCl2, bialaphos-resistant colonies were obtained. This indicated that transformation was successful. Southern blot analysis of total DNAs from transformants showed that the introduced plasmid DNA was integrated into the host chromosome and partly rearranged. A plasmid, pLC-GUS, containing the Escherichia coli beta-glucuronidase (GUS) gene under the control of the L. edodes ras gene promoter and priA gene terminator was constructed and introduced into protoplasts of P. ostreatus with pLC-bar by co-transformation. Two of 5 transformants obtained as bialaphos-resistant colonies showed two to twenty times higher specific activity of GUS than the recipient. Southern blot analysis of total DNAs from transformants indicated the presence of the GUS gene only in the two transformants. These results indicated that co-transformation of P. ostreatus was successful, and that the GUS gene was expressed in P. ostreatus. This transformation system will enable us to breed commercial strains of P. ostreatus at the molecular level.

DNA, Fungal↗
PubMed1996

Piperastatin A, a new selective serine carboxypeptidase inhibitor produced by actinomycete. I. Taxonomy, production, isolation and biological activities.

Piperastatin A (structure, N-formyl-allo Ile-Thr-Leu-Val-Pip-Leu-Pip, Pip = hexahydropyridadine-3-carboxylic acid; molecular weight, 809), a new inhibitor of serine carboxypeptidase was discovered in the fermentation broth of Streptomyces lavendofoliae MJ908-WF13. It was purified by activated charcoal chromatography, YMC gel ODS-A chromatography and centrifugal partition chromatography (CPC) by monitoring its inhibitory activity against carboxypeptidase Y (CP-Y), and finally obtained as colourless needles. Piperastatin A is a competitive inhibitor of the enzyme with Ki = 52 +/- 6.2 nM. Piperastatin A is a highly specific inhibitor of the serine carboxypeptidases, CP-Y and platelet deamidase with little effect on related enzymes, has no antimicrobial activity and has low toxicity.

Carboxypeptidases↗