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Biomedical subjects

M S Yang

Publications and source records attributed to M S Yang.

79 records · Page 5Linked to original sources
PubMed1983

An improved method for in situ freezing of cat brain for metabolic studies.

This study introduces a new method for rapid freezing of the cat brain. The method employed a Styrofoam box which was fitted around the head of the animal. Liquid nitrogen was poured into the box until the head was submerged. Temperature changes in three brain sites (ventral hypothalamus, the fourth ventricle, and the corpus callosum) and levels of labile carbohydrate metabolites (glycogen, glucose, ATP, P-creatine, and lactate) in five brain regions (cortex, thalamus, midbrain, cerebellum, and pons) frozen by the box method were compared with those frozen by a conventional cup method in which liquid nitrogen was poured into a hollow Styrofoam cup placed on top of the skull. The box method shortened the time of arrival of the freezing front and improved the freezing rate. The time required to bring the tissue to -20 degrees C was shortened, from 20 min at the ventral hypothalamus and 10-12 min at the fourth ventricle with the cup method, to less than 5 min at both sites with the box technique. Continued perfusion of brainstem prior to freezing was demonstrated. Levels of metabolites frozen by either method were similar. Lactate levels in any of the five brain regions studied by either method were not elevated, indicating no ischemic change.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1981

Distribution of cyclic nucleotide phosphodiesterase in mouse brain.

Seventy-one regions of mouse brain, and many subdivisions of some of these, were analyzed for cyclic nucleotide phosphodiesterase. The samples were dissected from lyophilized frozen sections. Since the average sample weighed only 25 ng (20 X 75 X 75 mu3), regions as small as the locus ceruleus could be analyzed. Activities in gray areas ranged 40-fold from a high in the pars reticulata of the substantia nigra to a low in the deep cerebellar nuclei. The activity in fiber tracts also varied about 40-fold, and on a lipid-free dry weight basis was similar to the activity in the gray matter where the fibers originated. The rank order for gray regions was basal ganglia, amygdala, hippocampus, cerebral cortex, most of the diencephalic nuclei, nuclei of the pons, cerebellum, and nuclei of the medulla.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1971

Elevated plasma activity of lactate dehydrogenase isoenzyme-3 (LDH 3 ) in experimentally induced immunologic lung injury.

Normal rats injected intravenously with rabbit antiserum to rat lung develop acute pulmonary lesions characterized by an altered vascular permeability. In the present study, an increase in plasma LDH(3) activity is shown to be positively correlated with the different levels of circulating antilung antibodies and with the morphologic severity of lung injury elicited by these pathogenic immunoglobulins. Within 24 hours, the acute lung changes are resolved, accompanied by a return of the activities of plasma LDH isoenzymes to normal. It is proposed that the plasma LDH(3) isoenzymes are released into the circulation from injured alveolar capillary endothelial cells.

Animals↗