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Biomedical subjects

A J Shah

Publications and source records attributed to A J Shah.

23 records · Page 2Linked to original sources
PubMed1988

Effect of fiber types, fascicle size and halothane on caffeine contractures in rat muscles.

Caffeine contractures were recorded from thin bundles and whole extensor digitorum longus (EDL) and soleus muscles of rat, and correlated with preparation size and fiber types. Thin bundles were more sensitive to caffeine and halothane than whole muscles, and bundles of 100% type I fibers were more sensitive than bundles of 100% type II fibers. Magnitude of contracture had significant correlation with maximal tetanic tension, total number of fibers, thickness of the preparation, and proportion of type I fibers. These results suggest that fascicle size and fiber types significantly affect results of in vitro contracture test for susceptibility to malignant hyperthermia.

Animals↗
PubMed1987

Expression of the Ca2+-binding protein, parvalbumin, during embryonic development of the frog, Xenopus laevis.

A cDNA segment encoding the Ca2+-binding protein, parvalbumin, was isolated with the use of antibodies, from a lambda gtll expression library of Xenopus laevis tadpole poly(A)+ RNAs. The bacterially expressed beta-galactosidase-parvalbumin fusion protein of one lambda recombinant shows high affinity 45Ca2+ binding. The sequence of the tadpole parvalbumin is highly similar to previously characterized beta-parvalbumins of other organisms. Data from protein and RNA blotting experiments demonstrate that parvalbumin is absent in oocytes, eggs, and early staged embryos, and only becomes expressed during embryogenesis at the time of myogenesis. The protein can be detected in individual developing muscle cells and in muscle fibers of tadpole tail muscles. A simple method is also described for the isolation of neural tube-notochord-somite complexes from Xenopus embryos.

Amino Acid Sequence↗
PubMed1983

Muscle in chronic uremia--a histochemical and morphometric study of human quadriceps muscle biopsies.

This report describes qualitative and quantitative studies performed on ten muscle biopsies from chronic uremic patients on renal dialysis at light and electron microscopic (EM) levels. The muscle biopsies showed myopathic changes (variation in fiber size, central nuclei, and fiber splitting). Histochemical studies showed type II fiber atrophy and lipid deposits. The ultrastructural study showed disruption of myofibrillary architecture and subsarcolemmal deposits of glycogen, mitochondria, and lipids. Quantitative estimations of the subcellular organelles revealed a statistically significant increase in lipid and glycogen contents of the muscle. The myopathic changes, type II atrophy, and lipid and glycogen deposits in chronic uremic patients raise the question of the effects of uremia and/or chronic dialysis on muscle metabolism.

Adult↗
PubMed1982

Morphogenesis of the mitochondrial alterations in muscle diseases.

In this paper we present sequential morphologic changes produced in rat muscle mitochondria. Respiratory toxins such as crotoxin (rattle-snake venom) and 2,4-dinitrophenol (DNP-an uncoupler of oxidative phosphorylation) were injected in rat quadriceps muscle and the mitochondrial alterations were studied at various time intervals. The series of mitochondrial changes consisted of rounding and swelling of mitochondria, unfolding of the cristae as straight lines, formation of the concentric rings, appearance of paracrystalline inclusions, formation of multiple vesicles and finally vacuole formation. These changes were comparable to the range of mitochondrial alterations seen in the human material examined. Similarity of the time-related mitochondrial changes in the rat to the spectrum of changes observed in human muscle biopsies suggests that the mitochondrial alteration in the human muscle disorders is a stepwise process in which respiratory alterations and calcium ion may play a role.

2,4-Dinitrophenol↗