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Biomedical subjects

S S Yang

Publications and source records attributed to S S Yang.

At least 145 records · Page 8Linked to original sources
PubMed1987

Detection of pullulanase in polyacrylamide gels using pullulan-reactive red agar plates.

After electrophoresis, active pullulanase bands in acrylamide gels have been detected by overlaying and then incubating the gel on a replica gel containing 2.5% pullulan-reactive red conjugate and 2.1% agar. The enzyme activity is revealed as a clear band against a red background on the replica gel. The sensitivity of the replica plate is such that 0.0012 unit of Klebsiella aerogenes pullulanase can be detected easily. This procedure is effective in enzyme screening to distinguish pullulanase from other carbohydrases.

Agar↗
PubMed1987

Thanatophoric dysplasia and cloverleaf skull.

Nine infants with thanatophoric dysplasia (TD) and cloverleaf skull (CS) are reported. Twenty-two previously published CSTD cases are reviewed. These CSTD cases are compared to cases of TD without CS. It is concluded that there are two types of TD: type 1, with curved femora and very flat vertebral bodies; and type 2, with straight femora and taller vertebral bodies. Consistent but subtle histopathological characteristics differentiate the two types. Only a very few type 1 cases have CS, and the CS is mild. Almost all type 2 cases have severe CS.

Female↗
PubMed1987

Three conditions in neonatal asphyxiating thoracic dysplasia (Jeune) and short rib-polydactyly syndrome spectrum: a clinicopathologic study.

Clinicopathologic examination of eight patients with asphyxiating thoracic dysplasia (Jeune; ATD) disclosed two different types, which were designated as type 1 and type 2. Type 1 ATD was characterized by the presence of radiologically irregular metaphyseal ends and histopathologically irregular cartilage bone junction with patchy distribution of physeal zone of hypertrophy. Type 2 ATD showed radiologically smooth metaphyseal ends and histopathologically diffusely retarded and disorganized physes with smooth cartilage bone junctions. Examination of four patients with the "Verma-Naumoff" short rib-polydactyly syndrome showed many radiologic and pathologic features similar to those of type 1 ATD. Differential diagnosis of these three osteochondrodysplasias is discussed along with chondroectodermal dysplasia (Ellis-van Creveld), short rib-polydactyly syndrome type 1 (Saldino-Noonan), short rib-polydactyly syndrome type 2 (Majewski), and the new short rib syndrome reported by Beemer et al [1983].

Asphyxia Neonatorum↗
PubMed1987

Brain-stem auditory evoked potentials in different types of hepatic diseases.

Brain-stem auditory evoked potentials (BAEPs) were studied in 69 patients with different types of hepatic diseases. BAEPs were normal in viral hepatitis, but the peak V and interpeak I-V latencies were prolonged in liver cirrhosis. Prolongation in peaks III, IV and V and interpeaks I-III, III-V and I-V were observed in both alcoholic liver disease and Wilson's disease with the latter more severely affected. The present data indicate that BAEPs may be used to study the effect of various hepatic diseases on the CNS.

Adult↗
PubMed1987

Inhibition of hydroxymethylglutaryl-coenzyme A synthase by L-659,699.

A beta-lactone isolated from Fusarium sp. has been shown to be a potent specific inhibitor of the enzyme 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) synthase [(S)-3-hydroxy-3-methylglutaryl-CoA acetoacetyl-CoA-lyase (CoA-acetylating), EC, 4.1.3.5] from rat liver. The structure of this beta-lactone, termed L-659,699, is (E,E)-11-[3-(hydroxy-methyl)-4-oxo-2-oxytanyl]-3,5,7-trimethyl-2,4 - undecadienenoic acid. A partially purified preparation of cytoplasmic HMG-CoA synthase from rat liver was inhibited by L-659,699 with an IC50 of 0.12 microM. The enzyme HMG-CoA reductase, beta-ketoacyl-CoA thiolase, acetoacetyl-CoA synthetase, and fatty acid synthase were not inhibited to any extent by this compound. In cultured Hep G2 cells, the compound inhibited the incorporation of [14C]acetate into sterols with an IC50 of 6 microM, while incorporation of [3H]mevalonate into sterols in these cells was not affected. The activity of HMG-CoA reductase in the cultured Hep G2 cells was induced in a dose-dependent manner by incubation with L-659,699. A 37-fold increase in reductase was observed after a 24-hr incubation with 62 microM L-659,699. The effect of a number of analogs of L-659,699 on HMG-CoA synthase is also discussed.

Animals↗
PubMed1987

Cloning of the debranching-enzyme gene from Thermoanaerobium brockii into Escherichia coli and Bacillus subtilis.

The gene for an enzyme with single or dual specificity on complex carbohydrates has been transferred from its native host (Thermoanaerobium brockii), a thermophilic anaerobe, into Escherichia coli and Bacillus subtilis. Most of the gene coding region is in a 2.2-kilobase PstI fragment that is common to the E. coli and B. subtilis chimeric vectors pCPC902 and pCPC903, respectively. Although the T. brockii debranching enzyme secreted from B. subtilis was unglycosylated and had less thermostability, more enzyme was secreted from B. subtilis (0.80 to 1.0 U/ml) than from T. brockii (0.23 U/ml). E. coli did not export any measurable enzyme. From the fermentation broth of B. subtilis containing pCPC903, three active species of the debranching enzyme were separated; two species are possibly protease digestion products of the larger protein (105,000 molecular weight). Whereas the enzyme can cleave all of the alpha-1----6 glucosidic linkages (and none of the alpha-1----4 bonds) in pullulan, it hydrolyzed mostly alpha-1----4 and very few of the alpha-1----6 linkages in starch. Upon hydrolysis of pullulan by the enzyme, only maltotriose was produced, while starch was digested to various-sized oligomers.

Bacillus subtilis↗
PubMed1987

A new bioprosthesis for aortic and mitral valve replacement: preliminary evaluation of the Tascon valve.

The Tascon valve, a new porcine bioprosthesis, features a detachable sewing ring designed to facilitate insertion and removal. Between April 1984 and June 1986, we implanted the Tascon valve in 25 patients, 12 of whom underwent aortic valve replacement (AVR), and 13 of whom had mitral valve replacement (MVR). Most of the patients were in NYHA class III or IV. Four MVR patients had had previous mitral valve operations, and three AVR patients required composite graft valved conduits. The valve's screw-locking mechanism worked well in all cases, especially in the AVR cases. There were no hospital deaths, and no significant morbidity or valve-related complications were encountered. One late death occurred 3 months after surgery, owing to causes unrelated to the valve. At the end of the study period, most of the survivors had improved by at least two NYHA functional classes. Postoperative aortic and mitral valve gradients and mitral valve areas, as measured by Doppler methods, were excellent. No significant regurgitation was detected. These favorable results indicate that the Tascon valve is a safe, useful bioprosthesis, with satisfactory hemodynamic characteristics.

Journal Article↗
PubMed1986

Demonstration of mitral valve function by cine computed tomography using a new long axis view.

Comparison was made between contrast enhanced cine computed tomography (Cine/CT) and echocardiography in the imaging of the mitral valve in 14 patients. The mitral valve was seen in all 14 patients by Cine/CT using a new long axis view. There was agreement with echocardiography in 12 patients. Abnormalities in mitral valve movement were detected by Cine/CT. Left atrial size and contraction was measured by Cine/CT with a difference in left atrial ejection fraction observed between 13 patients with no evidence of mitral disease and 3 patients with mitral disease.

Adult↗
PubMed1986

Lymphokine-induced cytotoxicity: characterization of effectors, precursors, and regulatory ancillary cells.

In the present study, we have characterized the effectors, precursors, and regulatory ancillary cells involved in the in vitro generation of lymphokine-induced cytotoxicity. It was first shown that at least two lymphokines are needed for the generation of lymphokine-induced cytotoxicity. They are interleukin 2 and a novel lymphokine, the cytotoxic cell differentiation factor (CCDF). CCDF was produced primarily by the macrophages. The effectors of the lymphokine-induced cytotoxic cells thus generated selectively killed tumor targets of different etiological origins. The serological phenotype of lymphokine-induced cytotoxic cell effectors were found to be Thy 1+, Lyt 2-, and AGM1-; therefore, they were neither classic natural killer (NK) cells nor cytotoxic T-lymphocytes. Extensive characterization of the precursors by sequential column separation and antibody lysis and also by limiting dilution analysis showed that they were AGM1+ and Lyt 2-; thus they were NK-like cells. In addition to NK-like cells being identified as the precursors, two other cell compartments were identified as ancillary cells which regulate the lymphokine-induced cytotoxicity. They were the macrophages and T-cells. Macrophages were needed to produce CCDF and to activate the Lyt 1+ helper T-cells to produce interleukin 2. The Lyt 2+ T-cells play a negative role in the regulation of the lymphokine-induced cytotoxic cell response. The process of lymphokine-induced cytotoxicity thus involves a complex interaction between at least two lymphokines (interleukin 2 and CCDF) and three cell compartments, namely, NK-like cells, macrophages, and T-cells of Lyt 1+ and Lyt 2+ phenotypes.

Animals↗
PubMed1986

Protease production with sweet potato residue by solid state fermentation.

The sweet potato residue being at the initial moisture content 50-58%, initial pH 3.5-4.3, supplemented with rice bran, and minerals, and incubated at 20-26 degrees C for 5 days was the optimal conditions for protease production with Aspergillus niger NTU-AM-1 by solid state fermentation. Protease could be recovered by shaking at room temperature for one hour and extracted with five times volume of 0.1% NaCl solution. The yield of protease was 814 units per gram dry weight of substrate. Partially purified protease with DEAE-Sephacel column chromatography was thermally stable and able to retain 80-100% of activity in pH 4.0-5.5 at 55 degrees C for 40 minutes. In addition, the activity of protease was stimulated by the presence of EDTA and cysteine, but was inhibited by the addition of HgCl2.

Aspergillus niger↗
PubMed1986

Protein enrichment of sugar beet residue with the inoculation of conidia of Trichoderma album by solid state fermentation.

Cellulosic material was inoculated with Trichoderma album by solid state fermentation and the change of protein, total nitrogen, mineral nitrogen, cellulose and total fiber contents of raw material were measured. It was found that the water holding capacity and bulk density of substrate increased as the fermentation progressed. The optimum C/N ratio for the conidia production was between 4 and 7, and the optimum pH was around 5. The protein enrichment of sugar beet residue were the best at the initial moisture content 76%, initial pH 4.5 and supplement with 1% nitrogen. After 4 days fermentation, the final product contained 22% of protein. From the present state of technological development, the protein enrichment of cellulosic materials by solid state fermentation proved to be valuable.

Fermentation↗