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Biomedical subjects

J B Peter

Publications and source records attributed to J B Peter.

At least 163 records · Page 9Linked to original sources
PubMed1975

Echocardiographic evaluation of posterior left ventricular wall motion in muscular dystrophy.

Maximal systolic endocardial velocity (SEVM) and maximal diastolic endocardial velocity (DEVM) were determined echocardiographically in patients with muscular dystrophy (MD). The SEVM of the muscular dystrophy patients was 5.5 +/- 0.9 cm/sec and the DEVM was 13 +/- 3 cm/sec. The SEVM in MD was significantly less than that seen in age-matched normals (P less than 0.05), persons with myotonia congenita (P less than 0.02), deconditioned patients (P less than 0.001), or older normal persons (P less than 0.05). The Sevm of the MD patients was not significantly different from persons with spinal muscular atrophy. The DEVM of the muscular dystrophy patients was significantly less (P less than 0.001-0.05) than any other group. No correlation could be found between age, heart rate, type or severity of dystrophy and SEVM or DEVM values. The echocardiogram was more selective in correctly identigying muscular dystrophy patients than the electrocardiogram. The abnormality in DEVM was present despite lack of symptoms, normal cardiovascular examination, normal chest X-ray and normal electrocardiograms in 18 of 22 patients. We believe that the DEVM correlates with myocardial relaxation.

Adolescent↗
PubMed1974

Stereological analysis of mammalian skeletal muscle. I. Soleus muscle of the adult guinea pig.

A quantitative analysis of the volumes, surface areas, and dimensions of the ultrastructural components in the soleus muscle fibers of the guinea pig was made by using point counting methods of stereology. Muscle fibers have structural orientation (anisotropy) and have spatial gradients of the structures within the fiber; therefore the standard stereological methods were modified where necessary. The entire analysis was repeated at two section orientations to test the modifications and identical results obtained from both. The volume of lipid droplets was 0.20 +/- 0.06% (mean +/- standard error, n = 5 animals) and the nuclei volume was 0.86 +/- 0.20% of the fiber volume. The total mitochondrial volume was 4.85 +/- 0.66% of the fiber volume with about one-third being found in an annulus within 1 microm of the sarcolemma. The mitochondrial volume in the remaining core of the fiber was 3.6 +/- 0.4%. The T system has a volume of 0.14 +/- 0.01% and a surface area of 0.064 +/- 0.005 microm(2)/microm(3) of the fiber volume. The surface area of the sarcolemma is 0.116 +/- 0.013 microm(2)/microm(3) which is twice the T system surface area. The volume of the entire sarcoplasmic reticulum is 3.52 +/- 0.33% and the surface area is 0.97 +/- 0.09 microm(2)/microm(3). The sarcoplasmic reticulum is composed of the terminal cisternae whose volume is 1.04 +/- 0.19% and surface area is 0.24 +/- 0.05 microm(2)/microm(3). The tubules of the sarcoplasmic reticulum in the I band and A band have volumes of 1.97 +/- 0.24% and 0.51 +/- 0.08%, and the surface areas of the I and A band reticulum are 0.56 +/- 0.07 microm(2)/microm(3) and 0.16 +/- 0.04 microm(2)/microm(3), respectively. The Z line width, myofibril and fiber diameters were measured.

Animals↗
PubMed1974

Human lymphocyte subpopulations. Effect of corticosteroids.

Normal subjects given 60 mg of prednisone orally at 8:00 a.m. developed a transient lymphopenia at 2:00 p.m. To define the populations of lymphocytes affected the number and type of lymphocytes in the peripheral blood were assayed. "Late" and "early" spontaneous sheep red blood cell rosettes were used as markers for thymus-derived (T) lymphocytes and one of its subpopulations, respectively. Receptors for aggregated gammaglobulin and complement identified bursal-equivalent or bone marrow-derived (B) lymphocytes and one of its subpopulations, respectively. 6 h after administration of 60 mg of prednisone, the blood samples showed a decrease in proportion of T cells from 69.2 +/- 2.1% to 55.9 +/- 2.8% (average +/- SE) and an increase in B-cell proportion from 21.3 +/- 2.0% to 44.8 +/- 4.1%. The changes of "early" rosettes and complement receptor lymphocytes also paralleled these. In all cases the absolute numbers of T cells and of B cells were decreased by prednisone. The density gradient distribution of the lymphocytes did not change after prednisone. These data indicate that both T and B lymphocytes are affected by the prednisone but that the T cell lymphopenia was more pronounced. The lymphopenia might reflect either sequestration in the marrow and/or transient arrest of recirculation.

B-Lymphocytes↗
PubMed1973

Diazacholesterol myotonia: accumulation of desmosterol and increased adenosine triphosphatase activity of sarcolemma.

Myotonia induced in rats by 20,25-diazacholesterol is accompanied by accumulation of desmosterol in serum, fragmented sarcoplasmic reticulum, and sarcolemma. Activities of (Na(+),K(+))- and Ca(2+)-stimulated adenosine triphosphatases of the sarcolemma are increased, but not the Mg(2+)-stimulated adenosine triphosphatase. The altered sterol composition of the sarcolemma may cause this type of myotonia by decreasing the chloride conductance of the membrane.

Adenosine Triphosphatases↗