[3H]gamma-aminobutyrate autoradiography of the rat olfactory bulb: hypothetical grain analysis of the distribution of silver grains.
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Animals↗
Biomedical subjects
D M Parry
Publications and source records attributed to D M Parry.
Evidence that fetal membranes are not involved in cortisol metabolism: study of dichorionic twin pregnancies.
11 beta-Hydroxysteroid dehydrogenase (11 beta-HSD, E.C.1.1.1.146) activity has been measured in samples of decidua, choriodecidua, and chorion obtained from five sets of dichorionic twins, with radiolabeled cortisol and cortisone used as substrates. 11 beta-HSD activity was significantly higher in the decidua than in the choriodecidua, in both the oxidative (cortisol to cortisone) are reductive (cortisone to cortisol) directions (activity expressed as percentage conversion): 53.4% +/- 6.7% versus 38.5% +/- 7.4% (p < 0.05) and 21.3% +/- 2.2% versus 15.3% +/- 3.2% (p < 0.025) (mean +/- SEM, n = 10). No measurable activity in either direction was found in the chorion obtained from the wall separating the two amniotic sacs (decidua-free chorion). In both decidua and choriodecidua oxidative activity was higher than reductive activity (p < 0.005 for both). These results demonstrate that 11 beta-HSD activity attributed to the chorion is due to decidual contamination.
11-beta-Hydroxysteroid Dehydrogenases↗
Renal phosphoenolpyruvate carboxykinase during perturbations of acid-base homeostasis in rats. Immunochemical studies.
The activity of phosphoenolpyruvate carboxykinase (PEPCK) increased in the rat kidney after induction of metabolic acidosis. Immunotitration of the enzyme in renal extracts from normal and acidotic rats indicate that this increase in catalytic activity correlates with the amount of immunotitrateable activity. PEPCK activity decreased rapidly during recovery from acidosis and the time required for the activity to return to normal was not altered by the administration of NaHCO3 at the start of recovery. Immunotitration of the enzyme from rats allowed to recover from metabolic acidosis revealed that the decrease in catalytic activity was paralleled by a decrease in the amount of immunotitrateable activity. It is concluded that the rise and fall in PEPCK activity during acidosis and recovery from acidosis, respectively, are due to comparable changes in enzyme protein.
Acidosis↗
Isotope decay range distribution curves for use in the analysis of electron microscope autoradiographs.
Analysis of autoradiographs at the electron microscope level requires special procedures, since the size of the radioactive structures visualized are comparable to the range of the radioactive decay particles emitted. Quantitative analysis in these circumstances requires that the sizes, shapes, and juxtaposition of the various structures be taken into account in relation to the range distribution of silver grains, produced by the decays, from a point source for the particular isotope and autoradiographic conditions employed. We present the distribution of silver grains about a point source for the four electron capture isotopes 51Cr, 55Fe, 111In, and 125I. Thin radioactive line sources were constructed and the distribution of autoradiographic grains measured. The grain distributions are discussed in relation to the number of particles per disintegration and their energy and range. A simple calculation enables these line source distributions to be converted into point source distributions, which can then be used for whichever method of quantitative analysis is considered appropriate for a particular problem. An outline is given of some of the more important aspects of various methods of analysis.
Autoradiography↗
Ultrastructural and cytochemical study of the bovine corpus luteum.
The large luteal cells comprise the bulk of the bovine corpus luteum during the most active secretory period of the oestrous cycle. At least 3 types of granules were present in mid-luteal cells: microperoxisomes, primary lysosomes and secretory granules. Only the last appear to be exocytosed. The concentration of these secretory granules in the luteal cytoplasm correlated with the reported profile of progesterone secretion by these cells throughout the cycle. Changes in the cytoplasmic proportions of the other subcellular organelles were consistent with the mobilization of steroid precursors stored in lipid droplets, synthesis of increased amounts of progesterone and protein, and the packaging of these products into discrete secretory granules.
Animals↗
Immunocytochemical localisation of prolactin and growth hormone in the perinatal sheep pituitary: a morphological and quantitative study.
The proxidase anti-peroxidase immunocytochemical staining technique has been used to identify prolactin and growth hormone cells in pituitaries from fetal and neonatal sheep. The size of the secretory granules in these cell types has been measured using the image analysing computer Quantimet 720. The area size distributions of the fetal prolactin and growth hormone granules were compared with those in the neonate and the adult. It appears that the gestional age of the fetus may influence the size range of prolactin secretory granules.
Animals↗
Sarcomas in a child and her father: an etiologic consultation.
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Adult↗
Subcellular location of progesterone in the bovine corpus luteum: a biochemical, morphological and cytochemical investigation.
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Animals↗
Immunocytochemical localisation of prolactin and growth hormone in the ovine pituitary. A morphological and quantitative study.
Using the peroxidase-antiperoxidase immunocytochemical staining technique, prolactin and growth hormone cells have been identified and described in the ovine pituitary. The image analysing computer, Quantimet 720, was used to assess accurately the size range of the secretory granules in these cell types. The area size distributions of the prolactin and growth hormone granules are similar. An increased proportion of larger granules was observed in the prolactin cells post-partum. Serial sections stained alternately for prolactin or growth hormone confirmed that the cells contain either prolactin or growth hormone but not both.
Animals↗
Electron microscope autoradiographic evidence for specific transneuronal transport in the mouse accessory olfactory bulb.
The distribution of radioactive material was examined autoradiographically 8 h after application of [3H] proline to the vomeronasal organ in mice. Labelled material was transported along the axons of the vomeronasal nerves to their terminals in the glomerular layer of the accessory olfactory bulb (AOB). A lesser but consistent amount of radioactivity was found in the external plexiform layer (EPL) of the AOB. Electron microscopic autoradiography was used to determine which of the components of the EPL contained this labelled material. The method of proportional grain counts showed that the highest concentration of silver grains lay over the mitral cell dendrites, which are the elements immediately postsynaptic to the vomeronasal nerve axons. However, a fairly high proportion of grains also lay over the peripheral processes of granule cells. By application of a method of 'crossfire analysis' (which is explained in detail) it was possible to show that the observed grain distribution is best explained by the assumption that the radioactive material is confined to mitral cells, and the labelling over granule cell processes is due to crossfire from these sources. Im one animal at 5 days after [3H]proline administration label was found to have extended from mitral cells to granule cells, suggesting that the transsynaptically transported radioactive material, which was confined to the mitral cells at 8 h, may have become further redistributed at longer survivals. In a control experiment, [3H]proline was applied directly to the surface of the AOB. This gave rise to a completely different distribution of radioactivity in the EPL: radioactive material was present in all tissue components.
Animals↗
Glutamine metabolism in the kidney during induction of, and recovery from, metabolic acidosis in the rat.
Experiments were carried out on rats to evaluate the possible regulatory roles of renal glutaminase activity, mitochondrial permeability to glutamine, phosphoenolpyruvate carboxykinase activity and systemic acid-base changes in the control of renal ammonia (NH(3) plus NH(4) (+)) production. Acidosis was induced by drinking NH(4)Cl solution ad libitum. A pronounced metabolic acidosis without respiratory compensation [pH=7.25; HCO(3) (-)=16.9mequiv./litre; pCO(2)=40.7mmHg (5.41kPa)] was evident for the first 2 days, but thereafter acid-base status returned towards normal. This improvement in acid-base status was accompanied by the attainment of maximal rates of ammonia excretion (onset phase) after about 2 days. A steady rate of ammonia excretion was then maintained (plateau phase) until the rats were supplied with tap water in place of the NH(4)Cl solution, whereupon pCO(2) and HCO(3) (-) became elevated [55.4mmHg (7.37kPa) and 35.5mequiv./litre] and renal ammonia excretion returned to control values within 1 day (recovery phase). Renal arteriovenous differences for glutamine always paralleled rates of ammonia excretion. Phosphate-dependent glutaminase and phosphoenolpyruvate carboxykinase activities and the rate of glutamine metabolism (NH(3) production and O(2) consumption) by isolated kidney mitochondria all increased during the onset phase. The increases in glutaminase and in mitochondrial metabolism continued into the plateau phase, whereas the increase in the carboxykinase reached a plateau at the same time as did ammonia excretion. During the recovery phase a rapid decrease in carboxykinase activity accompanied the decrease in ammonia excretion, whereas glutaminase and mitochondrial glutamine metabolism in vitro remained elevated. The metabolism of glutamine by kidney-cortex slices (ammonia, glutamate and glucose production) paralleled the metabolism of glutamine in vivo during recovery, i.e. it returned to control values. The results indicate that the adaptations in mitochondrial glutamine metabolism must be regulated by extra-mitochondrial factors, since glutamine metabolism in vivo and in slices returns to control values during recovery, whereas the mitochondrial metabolism of glutamine remains elevated.
Acid-Base Equilibrium↗
Waardenburg-like features with cataracts, small head size, joint abnormalities, hypogonadism, and osteosarcoma.
A 32-year-old black man was observed with osteosarcoma and multiple anomalies including deafness, hypopigmentation, cataracts, small head size, hypogonadism, and restricted joint mobility. The birth defects may comprise a new syndrome or combination of syndromes, of which the malignancy may be a part.
Abnormalities, Multiple↗
Renal glutamine metabolism in rats fed high-protein diets.
The influence of protein intake on acid excretion and renal glutamine metabolism was investigated and compared to the effects of NH4Cl-induced metabolic acidosis. Rats fed a diet containing 55% casein excreted more ammonia, phosphate, sulphate, and chloride than did rats fed a 13% casein diet, but, when they were given an 0.1 M NaHCO3 solution to drink, ammonia excretion was no longer elevated. Renal phosphate-dependent glutaminase and phosphoenolpyruvate carboxykinase activities, ammoniagenesis by isolated mitochondria, and the rate of renal gluconeogenesis were all elevated in the rats fed the high-protein diet but not if these rats also drank the sodium bicarbonate solution. Increased glutaminase and phosphoenolpyruvate carboxykinase activities, mitochondrial ammoniagenesis, and gluconeogenesis were all evident in rats made acidotic with NH4Cl. It is concluded that these metabolic adaptations evident in the kidneys of rats fed the high-protein diet are due to the acidogenic effects of increased protein intake.
Acid-Base Equilibrium↗
A simplified method of "hypothetical grain" analysis of electron microscope autoradiographs.
An improved method for the analysis of high resolution electron microscope autoradiographs is described which is simple and quick to perform. The method uses a transparent screen superimposed over the autoradiograph prints to provide information on the distribution of grains over neighboring structures, produced by radioactive disintegrations occurring in different regions of the section. This "cross-scatter" information is used to estimate the radioactivity in different structures without the need to make any assumptions about the size, shape and arrangement of the structures within the autoradiographs being analyzed. The method allows activity in membranes and other linear structures to be determined and also the accuracy attributable to the activity values obtained.
Autoradiography↗
Effects of exogenous progesterone and oestradiol on prostaglandin F and 13,14-dihydro-15-oxo prostaglandin F2alpha concentrations in uteri and plasma of ovariectomized ewes.
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Animals↗
Analysis of electron microscope autoradiographs using the hypothetical grain analysis method.
Cross-fire between adjacent labelled sources can often introduce problems in the analysis of electron microscope autoradiographs. A general method is described which makes allowance for this cross-fire and is then applied to the analysis of autoradiographs of 3H-proline in the accessory olfactory bulb of the mouse. It is shown how the method allows estimates to be made of the radioactivity of the various cell types and the accuracy of these estimates and the errors in obtaining them are discussed.
Animals↗
The genetic identification of a heterochromatic segment on the X chromosome of Drosophila melanogaster.
An autosomal euchromatic maternal-effect mutant, abo (= abnormal oocyte), interacts with, or regulates the activity of, the heterochromatin of the sex chromosomes of Drosophila melanogaster. It is shown that this interaction or regulation with the X chromosome involves a specific heterochromatic locus or small region that maps to the distal penultimate one-eighth of the basal X-chromosome heterochromatic segment.
Animals↗
Electron microscope autoradiography of erythroid cells using radioactive iron.
The "circle analysis" method of Williams (1969) and a new improved method employing hypothetical grains described in the previous paper have been used to analyze the distribution of autoradiographic grains over erythroid bone marrow cells labeled with radioactive iron, (55)Fe. The resolution obtainable with this isotope was determined by measuring the distribution of grains about a thin line source. This distribution was also used in calculation of the circle size for the Williams's analysis and the distances of hypothetical grains for the new method. The new method provides estimates for the amount of activity in the regions of condensed and extended nuclear chromatin and for the concentration of isotope at the junction between these two areas. The possible significance of activity in this junctional region is discussed.
Animals↗