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Biomedical subjects

S L Yang

Publications and source records attributed to S L Yang.

At least 127 records · Page 7Linked to original sources
PubMed1990

Analysis of voice of healthy aged persons with narrow band spectrum analyzer.

The purpose of this study is to measure the fundamental frequency (F0) and voice range of healthy aged persons. A total of 160 subjects without laryngeal or pulmonary complaints were involved in this study. The results were as follows. 1) F0: Results of the analysis indicated that the mean F0 of 70 to 74 years aged persons are higher than that of the other groups for male. There was, however, no significant difference among the groups for female. 2) Voice range: We found that the natural voice range for male decreases with increase of age, while the falsetto voice range increases. The natural voice range and falsetto voice range of females decrease with increase of age.

Age Factors↗
PubMed1990

Electromyographic study on end-to-end anastomosis of the recurrent laryngeal nerve in dogs.

The effectiveness of anastomosis of a divided recurrent laryngeal nerve was studied with electromyography as well as visual observation. Results obtained through this investigation permitted the following conclusions: 1. Regenerated potentials were recorded from both the involved thyroarytenoid and posterior cricoarytenoid muscles for an average of 5 to 6 weeks postoperatively. 2. Average onset of recovery of spontaneous adduction was 10 weeks following surgery, and four dogs regained complete recovery of adduction in 13 to 14 weeks. Average onset of recovery of spontaneous abduction was 11.8 weeks postoperatively, and none of the four dogs displayed complete recovery. 3. The time delay between the onset of regenerated potentials and onset of recovery of cord mobility averaged 4.2 weeks for adduction and 6.4 weeks for abduction. 4. Incomplete recovery of movements of the reinnervated vocal cord might be due to an inadequate number of effective motor units. 5. End-to-end anastomosis of the recurrent laryngeal nerve can be performed as one method of reinnervating the denervated intrinsic laryngeal muscles, and further histological studies should be carried out to determine if the regenerated nerve fibers actually have decreased.

Action Potentials↗
PubMed1990

A new method of needle-electrode placement in the posterior cricoarytenoid muscle for electromyography.

In 1979 the authors developed a new method of needle-electrode placement in the posterior cricoarytenoid muscle (PCA) for electromyography. The PCA muscle is easily reached by inserting a needle electrode through the cricothyroid membrane at the midline and penetrating the lamina of the cricoid cartilage in the subglottic cavity. Access to the PCA muscle for electrode insertion was best afforded by a percartilaginous approach. This report details the new technique used at our laboratory. To our knowledge, this is the first report of needle-electrode placement in the PCA muscle by a percartilaginous approach. This new electrode insertion technique has been applied to more than 100 dogs for research purposes and to 1200 patients with laryngeal motor disorders for clinical diagnosis. This is a simple technique requiring the usual skills. Reliable electromyographic recordings have been obtained by this new method. No untoward effects, such as hematoma or infection from repeated placements were observed in approximately 3200 examinations performed to date. It is reasonable to assume that the percartilaginous route for electrode insertion in the PCA muscle is feasible in man. Techniques of electrode placement in the intrinsic laryngeal muscles are reviewed and compared.

Adolescent↗
PubMed1990

[Studies on constituents of ganoderma capense IV. The chemical structures of ganoine, ganodine and ganoderpurine].

Two novel pyrrole alkaloids--ganoine and ganodine and a novel purine alkaloid ganoderpurine have been isolated from the mycelium of Ganoderma capense (Lloyd)Teng (Polyporaceae) obtained by submerged fermentation. On the basis of spectroscopic data their structures were elucidated, ganoine is N-isopentyl-5-hydroxymethyl-pyrryl alldehyde. Ganodine is N-phenylethyl-5-hydroxymethyl-pyrryl aldehyde and ganoderpurine is N9-(alpha, alpha dimethyl-gamma-oxobutyl) adenine.

Adenine↗
PubMed1990

Effects of lycobetaine on chromatin structure and activity of murine hepatoma cells.

The effects of lycobetaine (LBT) on DNA single strand break and chromatin conformation were examined by in-situ nick translation method. It was found that LBT did not cause DNA single strand break. After 2-h incubation of murine hepatoma cells with 1-50 micrograms/ml LBT in vitro, the chromatin transcription activity was inhibited gradually. This effect was time- and dose-dependent. Actinomycin D produced a similar effect; 10-hydroxycamptothecin not only caused DNA single strand break, but also altered chromatin conformation; homoharringtonine had no marked influence on either. By molecular hybridization technique, it was found that the effect of LBT on individual genes was somewhat different. After 2-h incubation of the cells with LBT, the sensitivities of c-myc, N-ras, and beta 2-microglobulin genes to DNase I were decreased from 75 +/- 6, 66 +/- 4, 70 +/- 8% to 28 +/- 8, 25 +/- 5, 28 +/- 7%, respectively, while that of c-myb and beta-globin genes (8 + 6%, 6 + 5%) did not change obviously.

Alkaloids↗
PubMed1989

Surgical management of severe liver trauma: a role for liver transplantation.

Severe devascularizing liver injuries continue to carry a high mortality. Rapid operative intervention to achieve hemostasis and debride devitalized tissue remains essential to salvaging these patients. For those with unsalvageable liver injuries liver transplantation can be employed. Careful support of the patient in the anhepatic state, reversal of coagulopathy, and use of venous bypass intraoperatively permit successful transplantation.

Adolescent↗
PubMed1989

New retrovirus helper cells with almost no nucleotide sequence homology to retrovirus vectors.

We prepared retrovirus packaging cell lines containing gag-pol genes from spleen necrosis virus (expressed from a cytomegalovirus promoter and the simian virus 40 (SV40) polyadenylation sequences) and, on a separate vector, either the env gene from spleen necrosis virus (expressed from the Rous sarcoma virus promoter and the SV40 polyadenylation sequences) or the env gene from amphotropic murine leukemia virus (expressed from a cytomegalovirus promoter and the SV40 polyadenylation sequences). The nucleotide sequences in these packaging cell lines have almost no homology to the retrovirus vectors we used. Retrovirus vectors were produced from these new helper cell lines without any genetic interactions between the vectors and sequences in the helper cells and without transfer of the packaging sequences.

Animals↗
PubMed1989

Characteristics of the interaction of lycobetaine with DNA.

The characteristics of the interaction of lycobetaine (LBT) with DNA were examined by fluorescence spectrometer, disc electrophoresis and restriction enzyme analysis. The apparent binding constant of LBT with calf thymus DNA has been determined as 1.67 x 10(6) L/mol by ethidium bromide displacement method. Based on electrophoresis titration, the mode of DNA binding was found to be through intercalation. Fluorescence quenching assay showed that the intrinsic association constant and the binding site size of LBT to calf thymus DNA were 0.26 x 10(6) L/mol and 2.6 base pairs, respectively. Selective inhibition of LBT on action of some restriction enzymes showed that LBT intercalate preferentially into GC base pairs. Neither DNA strand break nor interstrand cross-link was produced by LBT. LBT did not bind to DNA covalently and did not cause DNA alkylation.

Alkaloids↗
PubMed1988

Lung uptake of technetium-99m phosphate compounds after liver transplantation.

Pulmonary calcification can be detected easily using Tc-99m phosphate compounds. Lung uptake of Tc-99m bone imaging agents was observed in two patients after liver transplantation. Transient hypercalcemia due to calcium infusion during hepatic transplantation may be responsible for the pulmonary calcification.

Calcinosis↗
PubMed1987

Identification of a human liver cytochrome P-450 exhibiting catalytic and immunochemical similarities to cytochrome P-450 3a of rabbit liver.

Immunoblot analysis of liver microsomes from nine patients demonstrated that each contained a cytochrome P-450 that reacted with an antibody directed against the ethanol-inducible rabbit liver cytochrome, P-450 3a. Two of the liver specimens exhibited high concentrations of the immunoreactive protein, high rates of aniline hydroxylation and N-nitrosodimethylamine demethylation, and extensive inhibition of activity in the presence of antibody to P-450 3a. One other liver specimen exhibited a very low rate of aniline hydroxylation with significantly less antibody inhibition. The variability witnessed was independent of the alcohol history of the individual patients, suggesting that the human cytochrome may be under some other environmental, dietary or genetic regulation. Its inducibility by ethanol was not directly studied in this investigation. However, we conclude that there is a cytochrome P-450 present in human liver which is immunochemically and catalytically similar to the ethanol-inducible P-450 of rabbit liver.

Aniline Hydroxylase↗