Fitzgerald factor (high molecular weight kininogen) clotting activity in human plasma in health and disease in various animal plasmas.
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Fitzgerald factor (high molecular weight kininogen) is an agent in normal human plasma that corrects the impaired in vitro surface-mediated plasma reactions of blood coagulation, fibrinolysis, and kinin generation observed in Fitzgerald trait plasma. To assess the possible pathophysiologic role of Fitzgerald factor, its titer was measured by a functional clot-promoting assay. Mean +/- SD in 42 normal adults was 0.99+/-0.25 units/ml, one unit being the activity in 1 ml of normal pooled plasma. No difference in titer was noted between normal men and women, during pregnancy, or after physical exercise. Fitzgerald factor activity was significantly reduced in the plasmas of eight patients with advanced hepatic cirrhosis (0.40+/-0.09 units/ml) and of ten patients with disseminated intravascular coagulation (0.60+/-0.30 units/ml), but was normal in plasmas of patients with other congenital clotting factor deficiencies, nephrotic syndrome, rheumatoid arthritis, systemic lupus erythematosus, or sarcoidosis, or under treatment with warfarin. The plasmas of 21 mammalian species tested appeared to contain Fitzgerald factor activity, but those of two avian, two repitilian, and one amphibian species did not correct the coagulant defect in Fitzgerald trait plasmas. (+info)
Evidence for a correlation between the number of marginal band microtubules and the size of vertebrate erthrocytes.
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In 23 species of vertebrates the dimensions of erythrocytes and the number of their marginal band microtubules were examined. A positive correlation was found between the size of erythrocytes and the number of microtubules. The absence of microtubules in diskoid erythrocytes of mammals-Camelidae-is discussed. (+info)
Activities of citrate synthase, NAD+-linked and NADP+-linked isocitrate dehydrogenases, glutamate dehydrogenase, aspartate aminotransferase and alanine aminotransferase in nervous tissues from vertebrates and invertebrates.
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1. The activities of citrate synthase and NAD+-linked and NADP+-linked isocitrate dehydrogenases were measured in nervous tissue from different animals in an attempt to provide more information about the citric acid cycle in this tissue. In higher animals the activities of citrate synthase are greater than the sum of activities of the isocitrate dehydrogenases, whereas they are similar in nervous tissues from the lower animals. This suggests that in higher animals the isocitrate dehydrogenase reaction is far-removed from equilibrium. If it is assumed that isocitrate dehydrogenase activities provide an indication of the maximum flux through the citric acid cycle, the maximum glycolytic capacity in nervous tissue is considerably greater than that of the cycle. This suggest that glycolysis can provide energy in excess of the aerobic capacity of the tissue. 2. The activities of glutamate dehydrogenase are high in most nervous tissues and the activities of aspartate aminotransferase are high in all nervous tissue investigated. However, the activities of alanine aminotransferase are low in all tissues except the ganglia of the waterbug and cockroach. In these insect tissues, anaerobic glycolysis may result in the formation of alanine rather than lactate. (+info)
Characterization of toad liver glutathione transferase.
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The major form of glutathione transferase from the toad liver previously designed as Bufo bufo liver GST-7.6 (A. Aceto, B. Dragani, T. Bucciarelli, P. Sacchetta, F. Martini, S. Angelucci, F. Amicarelli, M. Miranda and C. Di Ilio, Biochem. J. 289 (1993) 417-422) has been characterized. According to its partial amino acid sequence, the toad enzyme may be included in the pi class GST and named bbGST P2-2. However, bbGST P2-2 appears to be immunologically, structurally and kinetically distinct from any other members of pi family, including bbGST P1-1, suggesting that it may constitute a subset of pi class GST. The data support the hypothesis that the transition from aquatic to terrestrial life causes a switch of the GST amphibian pattern promoting the expression of a GST form (bbGST P2-2) able to counteract, with higher efficiency, the toxic effects of reactive metabolites of oxidative metabolism and those of hydrophobic xenobiotics. (+info)
Peptide growth factors in amphibian embryogenesis: intersection of modern molecular approaches with traditional inductive interaction paradigms.
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Recent discoveries of the role peptide growth factors (PGFs) play in regulating embryonic patterning and differentiation have profoundly influenced research on the molecular biology of early amphibian embryogenesis. Several PGFs have been recognized to be present as endogenous components of amphibian eggs and early embryos, while other PGFs -- which are known from heterologous systems (e.g., Drosophila) -- exert remarkable effects when injected as either protein or mRNA into eggs/embryos or when added to cultured embryonic tissue. For a variety of reasons (reviewed herein) optimism abounds that an understanding in molecular terms of the classical Spemann and Nieuwkoop tissue interactions which are generally believed to drive embryonic patterning is within reach. A critical assessment of the interpretations of some of the contemporary data on PGFs (included herein) should, however, temper some of that optimism. Likely, multiple rather than single PGFs act in a combinatorial fashion to contribute to individual patterning events. As well, substantial redundancy in PGF regulatory circuits probably exists, so the heavy reliance on tissue culture assays and overexpression studies which characterize much recent research needs to be circumvented. Potential experimental approaches for "next generation" experiments are discussed. (+info)
Histology of the kidney and urinary bladder of Siphonops annulatus (Amphibia-Gymnophiona).
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The histology of the kidney and urinary bladder of Siphonops annulatus was studied by light microscopy in semithin sections of tissue embedded in hydrophilic resin. The kidney's nephron comprises the renal corpuscle, neck segment, proximal tubule, intermediate segment, distal tubule and collecting tubule. Nephrostomes are present. This structure, the neck segment, and intermediate tubules present long cilia, and probably play important roles in the propulsion of the peritoneal fluid and glomerular filtrate. The proximal tubule cells possess loosely packed microvilli and contain abundant polymorphic granules and vesicles that assume the aspect of lysosomes in different stages of intracellular digestion. The distal tubules are characterized by large, vertically disposed mitochondria assuming the aspect of ions transporting cells. The urinary bladder is lined with a transitional epithelium, whose aspect varies according to the quantity of urine. (+info)
Classification of loops of lampbrush chromosomes according to the arrangement of transcriptional complexes.
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The arrangement of transcriptional units in the loops of lampbrush chromosomes from oocyte nuclei of urodele amphibia and from primary nuclei of the green alga Acetabularia have been studied in the electron microscope using spread preparations. Loops with different patterns of arrangement of matrix units (i.e. to a first approximation, transcriptional units) can be distinguished: (i) loops consisting of one active transcriptional unit; (ii) loops containing one active transcriptional unit plus additional fibril-free, i.e. apparently untranscribed, intercepts that may include 'spacer' regions; (iii) loops containing two or more transcriptional units arranged in identical or changing polarities, with or without interspersed apparent spacer regions. Morphological details of the transcriptional complexes are described. The observations are not compatible with the concept that one loop reflects one and only one transcriptional unit but, rather, lead to a classification of loop types according to the arrangement of their transcriptional units. We propose that the lampbrush chromosome loop can represent a unit for the coordinate transcription of either one gene or a set of several (different) genes. (+info)
Immunolocalization of mitsugumin29 in developing skeletal muscle and effects of the protein expressed in amphibian embryonic cells.
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The temporal appearance and subcellular distribution of mitsugumin29 (MG29), a 29-kDa transmembrane protein isolated from the triad junction in skeletal muscle, were examined by immunohistochemistry during the development of rabbit skeletal muscle. MG29 appeared in the sarcoplasmic reticulum (SR) in muscle cells at fetal day 15 before the onset of transverse tubule (T tubule) formation. In muscle cells at fetal day 27, in which T tubule and triad formation is ongoing, both SR and triad were labeled for MG29. In muscle cells at newborn 1 day, the labeling of the SR had become weak and the triads were well developed and clearly labeled for MG29. Specific and clear labeling for MG29 was restricted to the triads in adult skeletal muscle cells. When MG29 was expressed in amphibian embryonic cells by injection of the cRNA, a large quantity of tubular smooth-surfaced endoplasmic reticulum (sER) was formed in the cytoplasm. The tubular sER was 20-40 nm in diameter and appeared straight or reticular in shape. The tubular sER was formed by the fusion of coated vesicles [budded off from the rough-surfaced endoplasmic reticulum (rER)] and vacuoles of rER origin. The present results suggest that MG29 may play important roles both in the formation of the SR and the construction of the triads during the early development of skeletal muscle cells. (+info)