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Biomedical subjects

W Chen

Publications and source records attributed to W Chen.

At least 1,225 records · Page 68Linked to original sources
PubMed1981

Adrenoleukodystrophy: increased plasma content of saturated very long chain fatty acids.

With a new method we measured the saturated very long chain fatty acids in the plasma of adrenoleukodystrophy (ALD) hemizygotes, ALD heterozygotes, and controls. ALD hemizygotes showed increased levels of hexacosanoate (C26 fatty acid) which represented 0.081 +/- 0.0066% (SEM) of total fatty acids, compared to 0.015 +/- 0.0032% in the controls. C25, C24, and C23 fatty acids were also increased, but the C22 and C20 fatty acids were normal. C26 levels were also increased in most ALD heterozygotes, with a mean level 0.057 +/- 0.0063% of total fatty acids. The technique can be used for diagnosis and carrier identification, and in the evaluation of therapy.

Adolescent↗
PubMed1981

Comparison of sensory modes of biofeedback in relaxation training of frontalis muscle.

The purpose of this study was to compare the effectiveness of various sensory modes of EMG biofeedback to relaxation training of the frontalis muscle. 19 male and 29 female subjects were randomly selected from a pool of college volunteers. They were then randomly assigned 12 each to audiofeedback, visual feedback, audiovisual feedback, and no feedback groups. There were 11 20-min. sessions per subject. Subjects in the biofeedback groups were trained to reduce muscle tension voluntarily by utilizing Cyborg J33 EMG portable trainers. The subjects in the three feedback groups exhibited significantly lower muscle tension than did the subjects in the no-feedback control group. There were no significant differences in relaxation among the three feedback groups.

Adult↗
PubMed1981

Functional characterization of mouse lymphocyte subpopulations identified by their natural binding of bacteria. II. Identification of subpopulations of LY-1 + 2-3-, LY-1-2+3+ and LY-1+2+3+ cells and the localization of specific cytotoxic cells in a subset of LY-1-2+3+ cells .

Three T-cell subpopulations (T1, T2 and T3) can be identified by their binding of various bacteria (Mayer, Chen, Dray & Teodorescu, 1978). In this work we determined how the three subpopulations identified by their Ly-1, -2 and -3 alloantigens were distributed among the T1, T2 and T3 subpopulations. We found that the T1 subpopulation contained most of the Ly-1+2+3+ cells, that the T2 subpopulation contained some Ly-1+2-3- and some Ly-1-2+3+ cells and that the T3 subpopulation contained the remainder of the Ly-1+2+3+, Ly-1+2-3- and Ly-1-2+3+ cells. Thus the subpopulations identified by their bacterial adherence properties subdivided the three subpopulations identified by their Ly-1, -2 and -3 alloantigens. We also investigated whether the specific cytotoxic T lymphocytes were contained in the T1, T2 and/or T3 cells. We found that essentially all of the cytotoxic T lymphocytes were contained in the T3 subpopulation. Since the T3 cells contained a subpopulation of Ly-1-2+3+ cells the data indicated that essentially all of the cytotoxic T lymphocytes were contained in a subpopulation of Ly-1-2+3+ cells.

Animals↗
PubMed1980

A case of malignant lymphoma, undifferentiated, Burkitt's type with high antibodies to Epstein-Barr virus.

A 5-year-4-month-old girl was admitted to Taipei Municipal Jen-Ai Hospital because of a rapidly enlarging right submandibular tumor. The diagnosis of malignant lymphoma, undifferentiated, Burkitt's type was made by distinctive histopathological features. Positive serological findings related to Epstein-Barr virus infection were disclosed. Complete remission has been achieved since the treatment with high-dose cyclophosphamide was given, and no signs of relapse have been found yet.

Antibodies, Viral↗
PubMed1980

A mouse model of pneumonitis induced by Chlamydia trachomatis: morphologic, microbiologic, and immunologic studies.

Swiss-Webster white mice were infected with Chlamydia trachomatis organisms through intranasal inoculation. It was found that a typical interstitial pneumonitis could be induced. Histopathologic findings showed that the lung infiltration was predominantly polymorphonuclear cells and was most prominant on Day 2. The cellular infiltrate gradually changed to mononuclear cells after Day 3. Intracytoplasmic inclusions were frequently found in the interstitial cells and occasionally in the bronchial epithelial cells. Typical chlamydial bodies (elementary, intermediate, and reticulate forms) were identified by electron microscopy. The organisms were recovered from mouse lungs on Days 1--7, with the highest yields on Day 2. This correlated with the peak of lung infiltration seen by histologic examination. Antibodies specific to the infecting immunotype began to appear between Day 7 and Day 10 after inoculation and lasted until Day 35 without a decline in titers. A delayed hypersensitivity reaction was observed by footpad test from Day 5 to Day 21, with the peak reaction at Day 7. This study showed that the mouse model could be used to study the immunopathogenesis of C trachomatis infection.

Animals↗
PubMed1980

The effect of a body burden of methylmercury on hepatic regeneration.

The model of hepatic regeneration is chosen to study the effect of methylmercury burden on cell proliferation. The results show that chronic methylmercury burden impedes the rate of thymidine incorporation during the process of DNA synthesis. At 24 hours after partial hepatectomy, thymidine incorporation in the mercury exposed rats is 53% of the controls. Counts of labeled hepatocytes in radioautographic preparations also support this observation. This remarkable difference in DNA synthetic activity at 24 hours also reflects in the DNA content and liver, weights at 72 hours after partial hepatectomy (Liver weights 2.36 +/- 0.21 gm/100 gm B. W. vs. 2.67 +/- 0.31 gm/100 B. W., P < 0,05; DNA contents 160.78 +/- 36.76 microgram/gm vs. 214.80 +/- 37.908 microgram/gm, P < 0.05). After two weeks, no significant difference is noted in liver weight, DNA content and synthetic activity. On the other hand, protein content and biosynthesis in the liver of methylmercury burdened rats shows no significant difference from the controls in all the periods studied. From these data it is concluded that the dividing fraction of hepatocytes is reduced in methylmercury-treated group at an early stage of regeneration when cell proliferation is most active.

Animals↗
PubMed1979

Mechanisms of prolongation of pre-ejection period in patients with left ventricular disease.

In order to determine the mechanism underlying prolongation of the pre-ejection period in patients with left ventricular disease, 11 patients with congestive cardiomyopathy and 29 with coronary artery disease, 10 of whom were taking beta-adrenergic blocking drugs, were studied non-invasively. Recordings of carotid pulse, and apex, phono-, and echocardiogram were obtained. In the absence of treatment with beta-blocking drugs, prolongation of pre-ejection period correlated closely with incoordinate left ventricular wall movement during isovolumic contraction assessed from simultaneous apex and echocardiograms. There was no correlation between pre-ejection period index (PEPI) and end-diastolic dimension and PEPI correlated poorly with fractional shortening and peak Vcf. A PEPI of greater than 140 ms was associated with incoordinate contraction in all but one case, and of less than 140 ms with normal contraction in all. Therapeutic doses of beta-blocking drugs caused prolongation of PEPI to a greater extent than would have been predicted from wall movement during isovolumic contraction. Incoordinate left ventricular contraction and a negative inotropic effect both therefore prolong PEPI, but by different mechanisms, whose effects can be separated in individual patients using non-invasive methods based on echocardiography.

Adrenergic beta-Antagonists↗
PubMed1979

The effect of methylmercury on isolated cardiac tissues.

The effect of methylmercury hydroxide (MMH) on the frequency of spontaneously beating atrial-SA node and on the isometric tension of electrically stimulated left atrial (1 Hz) preparation isolated from rats were investigated. The tissues were also fixed for ultrastructural study at the end of the experiments. We found that MMH, at low doses (0.5 and 2ppm), increased the frequency of contractions and the isometric tension of isolated atria and decreased the isometric tension of isolated papillar muscles, and at higher doses (greater than 2ppm), decreased all the above parameter. Morphologically, there were dilation and swelling of mitochondrial and sarcoplasmic reticulum. Occasionally, deposits of amorphous material in the mitochondria and myofibrillary degeneration of myocardial fibers were noted. It is concluded the MMH has direct effect on intracellular organelles (mitochondria, sarcoplasmic reticulum, and myofibril) of myocardial tissue and induces functional changes of atria and papillary muscles

Animals↗