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Biomedical subjects

T Yamauchi

Publications and source records attributed to T Yamauchi.

At least 19 recordsLinked to original sources
PubMed1979

Abnormalities of erythrocyte membranes in biliary atresia: ultrastructure and lipid composition.

Biochemical and ultrastructural studies of red blood cell membranes from seven patients with congenital biliary atresia have been performed. Scanning electron microscopic observations revealed that more than half of these cells were of abnormal shapes, such as target, spur and cup-formed cells. By freeze-fracture electron microscopy, membrane particle-free smooth areas were noted in the fracture faces. In addition, the number of membrane-associated particles was 20% less than those in control subjects. The lipid analysis of red blood cells showed a significant increase in phospholipid and a marked increase in cholesterol content. The increase of phospholipid content was primarily caused by the increase of lecithin. The acyl chain analysis of erythrocyte lecithin demonstrated an increase in palmitic, palmitoleic and oleic acid, and a decrease in stearic and linoleic acid. These observations are similar to those of acquired biliary obstruction. The fluidity of erythrocyte membrane lipid, studied by a fluorescence technique using fluorescent probe 1,6-diphenyl-1,3,5-hexatriene (DPH), was found to be less in an individual with congenital biliary atresia than in the control subject.

Bile Ducts↗
PubMed1979

Phenylalanine hydroxylase from Chromobacterium violaceum. Purification and characterization.

Phenylalanine hydroxylase was purified approximately 3000-fold to apparent homogeneity with a 13% yield and crystalized from L-phenylalanine-induced cells of Chromobacterium violaceum. The enzyme was shown to be composed of a single polypeptide chain with an estimated molecular weight of approximately 32,000. Some of the physical properties of the enzyme include: a Stokes radius of 26.0 A, a sedimentation coefficient of 2.71 S, a diffusion coefficient of 8.20 X 10(-7) CM2/S, a frictional ratio of 1.23, and an isoelectric point of pH 4.5. No detectable iron was found in the purified enzyme. Apparent Km values for L-phenylalanine and 2-amino-4-hydroxy-6,7-dimethyltetrahydropteridine were 140 and 54 muM, respectively.

Catalysis↗
PubMed1979

In vitro phosphorylation of bovine adrenal tyrosine hydroxylase by adenosine 3':5'-monophosphate-dependent protein kinase.

We have studied the effects of adenosine 3':5'-monophosphate (cAMP)-dependent protein kinase on the phosphorylative and functional modification of bovine adrenal tyrosine hydroxylase. Incubation of partially purified tyrosine hydroxylase with cAMP-dependent protein kinase in the presence of [gamma32P]ATP and 5 micron cAMP led to a 3- to 5-fold activation of tyrosine hydroxylase and to incorporation of [32P]phosphate into protein. When tyrosine hydroxylase preparations activated by exposure to enzymatic phosphorylating conditions were analyzed by sucrose density gradient centrifugation, polyacrylamide gel electrophoresis, and gel electrofocusing, the radioactivity of 32P was coincident with the activity of tyrosine hydroxylase, suggesting incorporation of 32P from [gamma-32P]ATP into tyrosine hydroxylase. Polyacrylamide gel electrophoresis of the phosphorylated tyrosine hydroxylase preparation in the presence of 0.1% sodium dodecyl sulfate revealed that the 60,000-dalton polypeptide subunit of tyrosine hydroxylase served as the phosphate acceptor.

Adrenal Medulla↗
PubMed1979

Clinical studies on carcinoembryonic antigen in pancreatic cancer.

We studied serum carcinoembryonic antigen (CEA) levels in 82 patients. Thirty-four of these had benign diseases while 48 had malignant diseases. Highest incidence and levels of CEA occurred in the sera of patients with pancreatic cancer and stomach cancer. In this paper we focused our particular attention on the serum CEA of 25 pancreatic cancer patients, and examined differences in serum CEA levels in relation to histologic differentiation and sites of pancreatric cancer. No statistical difference in serum CEA level was found among various histologic types and sites of the pancreatic cancer. Clinical courses of two patients with pancreatic cancer were also studied. Serial determinations of CEA levels are most useful in assessing the effect of operation or chemotherapies and are a useful indicator for differentiating pancreatic cancer from chronic pancreatitis but cannot be a conclusive factor for the diagnosis. Finally, we correlated serum CEA levels with those of RNase and confirmed a positive correlation.

Carcinoembryonic Antigen↗
PubMed1979

Treatment of bacterial meningitis with intravenous amoxicillin.

Eleven children with bacterial meningitis were treated intravenously with amoxicillin sodium to evaluate the efficacy of the parenteral form of amoxicillin for this serious infection and to measure the penetration of the drug into cerebrospinal fluid (CSF). The infecting organisms were Haemophilus influenzae in nine cases and Streptococcus pneumoniae in two. Nine patients had optimal responses to amoxicillin sodium, 200 mg/kg per day for 14 days. Bacteria were also eradicated from CSF of the other two, but one experienced fever and culture-negative CSF pleocytosis after cessation of amoxicillin, and the other developed H. influenzae empyema 2 weeks after termination of therapy. By comparison, 7 of 10 children with meningitis responded optimally to ampicillin (nonrandomized design) during the period of study. The mean peak CSF concentration of amoxicillin was 3.14 mug/ml (ca. 7% of the concomitant mean peak serum level) early during therapy. However, meningeal penetration of the drug declined to a mean peak of 0.63 mug/ml on the final day of therapy. Mild transient neutropenia, noted in five patients, was the most common side effect of amoxicillin sodium therapy; five patients treated with ampicillin also experienced reversible neutropenia. Thus, intravenous amoxicillin sodium provided therapy for bacterial meningitis comparable to that of ampicillin in this limited case-control study.

Amoxicillin↗