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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ultrastructural analysis including scanning and transmission electron microscopic studies (SEM and TEM) were carried out on oyster gill tissue after exposure either to serum fractions from individuals homozygous or heterozygous for cystic fibrosis (CF), to comparable serum fractions from normal individuals, or to sea water. In 4 of the experiments examined topologically (SEM), the CF sera (either heterozygous or homozygous) stimulated the production of mucus that was found in close association with the cilia. The association of excessive mucus with the cell surface could be responsible, in part, for the well-known inhibition of ciliary activity by a factor in CF serum. In 3 additional SEM experiments involving shorter treatment times, very little difference could be observed between homozygous CF, heterozygous CF, and normal serum-fraction-treated oyster tissues. In parallel experiments, ultrathin sections of gill tissue were examined by means of TEM. Those samples that were responsive, as determined by TEM, displayed several characteristic features, including enlarged and partially exuded goblet cells, altered mucus structure along with twisted and matted cilia. An overall swelling of the gill filament was also observed in the responsive tissues. From TEM analysis no detectable alteration in fine structure was apparent in gill tissues that were treated with sera from heterozygous or normal individuals.
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PMID:Effects of cystic fibrosis serum ciliary inhibitor on oyster gill ultrastructure: analysis by scanning and transmission electron microscopy. 99 86

In experiments in which blood was cross-circulating in rats, the blood pressure of the recipient dropped while that of the donor rose, following the increase of the circulating blood volume, produced by infusion either of saline or blood. The phenomenon was almost imperceptible when binephrectomized animals were used. In experiments in which the blood-bathed organ technique was used, prostaglandin-like substances were detected, released during the rise of the blood pressure, produced by the same stimulus (the expansion), in anaesthetized rats. A significant difference was found between the prostaglandin-like substances detected using the blood-bathed organ technique, in normal rats (5.387 ng per ml of blood plus or minus 0.288 = SEM) and those detected in binephrectomized rats (3.202 ng per ml of blood plus or minus 0.330, p smaller than 0.025). The biologically active substances detected in 25 ml of blood collected during expansion, while the assay organs showed a prostaglandin-like activity, were found to have the chromatographic behaviour and the bioassay properties of PGA, PGE and PGF series. A great quantity of the biologically active substances, having the chromatographic behaviour and the bioassay properties of PGA, PGS and PGF was detected in the rat renal medulla. Sufficient quantities of the released prostaglandin-like substances could escape the pulmonary vascular bed in this species of animal. It was concluded that a great quantity of the released prostaglandin-like substances came from the kidney and their release by this particular mechanism suggested that they play an important homeostatic role on the blood pressure, blood volume, and sodium and water balance regulation.
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PMID:[Origin, nature, role and fate of prostaglandins liberated during the expansion of intravascular space in the anesthetized rat]. 109 32

The effects of insulin on the renal handling of sodium, potassium, calcium, and phosphate were studied in man while maintaining the blood glucose concentration at the fasting level by negative feedback servocontrol of a variable glucose infusion. In studies on six water-loaded normal subjects in a steady state of water diuresis, insulin was administered i.v. to raise the plasma insulin concentration to between 98 and 193 muU/ml and infused at a constant rate of 2 mU/kg body weight per min over a total period of 120 min. The blood glucose concentration was not significantly altered, and there was no change in the filtered load of glucose; glomerular filtration rate (CIN) and renal plasma flow (CPAH) were unchanged. Urinary sodium excretion (UNaV) decreased from 401 plus or minus 46 (SEM) to 213 plus or minus 18 mueq/min during insulin administration, the change becoming significant (P smaller than 0.02) within the 30-60 min collection period. Free water clearance (CH2O) increased from 10.6 plus or minus 0.6 to 13 plus or minus 0.5 ml/min (P smaller than 0.025); osmolar clearance decreased and urine flow was unchanged. There was no change in plasma aldosterone concentration, which was low throughout the studies, and a slight reduction was observed in plasma glucagon concentration. Urinary potassium (UKV) and phosphate (UPV) excretion were also both decreased during insulin administration; UKV decreased from 66 plus or minus 9 to 21 plus or minus 1 mueq/min (P smaller than 0.005), and tupv decreased from 504 plus or minus 93 to 230 plus or minus 43 mug/min (P smaller than 0.01). The change in UKV was associated with a significant reduction in plasma potassium concentration. There was also a statistically significant but small reduction in plasma phosphate concentration which was not considered sufficient alone to account for the large reduction in UPV. Urinary calcium excretion (UCaV) increased from 126 plus or minus 24 to 200 plus or minus 17 mug/min (P smaller than 0.01). These studies demonstrate a reduction in UNaV associated with insulin administration that occurs in the absence of changes in the filtered load of glucose, glomerular filtration rate, renal blood flow, and plasma aldosterone concentration. The effect of insulin on CH2O suggests that insulin's effect on sodium excretion is due to enhancement of sodium reabsorption in the diluting segment of the distal nephron.
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PMID:The effect of insulin on renal handling of sodium, potassium, calcium, and phosphate in man. 112 Jul 86

Bile flow, erythritol clearance (measured after administration of 14-C-erythritol) and bile acid excretion were studied in 8 non-icteric patients operated upon for gallstone disease without biliary obstruction in whom a T-tube had been inserted. Bile flow increased from the 2nd (0.27 plus or minus SEM 0.01 ml/min) to the 7th (0.50 plus or minus SEM 0.05 ml/min) postoperative days and remained stable thereafter. Because the values obtained between the 7th and the 15th postoperative days (average: 0.46 plus or minus SEM 0.02 ml/min) were not lower and were of the same order of magnitude as those previously reported in the literature for quantitative bile collections, it was assumed that bile collection had been complete. Bile-to-plasma concentration ratio of erythritol was 0.77 plus or minus SEM 0.04. The regression line between erythritol clearance and bile flow had a slope of 0.99 (indicating that increments in clearance were followed by equivalent increments of flow) and an intercept for a zero-clearance of 0.11, suggesting a ductular/ductal secretion of 0.11 ml/min. The relationship between erythritol clearance and bile acid excretion suggested that canalicular bile was formed both of a bile acid-dependent flow (11 mul of water being excreted per mumol of bile acid secreted) and a bile acid-independent flow of 0.16 ml/min (or 35 percent of the average bile flow). These findings indicate that erythritol clearance provides a valid estimate of canalicular bile flow in man and that the three bile fractions previously postulated in animals (canalicular bile acid-dependent, canalicular bile acid-independent and ductular/ductal) may also be present in man.
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PMID:Canalicular bile production in man. 112 19

The aims were to examine the effects of scoliosis (angle), and age on lung volumes, elastic properties of the respiratory system, and the ventilatory response to CO2. The mean age of the 55 patients was 25.4 plus or minus SEM 2.5 yr, and the mean angle was 80 plus or minus SEM 4.2. The mean plus or minus SEM percent predicted lung volumes were vital capacity (VC), 60.5 plus or minus 2.7; total lung capacity (TLC), 70,2 plus or minus 2.6; functional residual capacity (frc), 79.3 plus or minus 3.2; and residual volume (RV), 99.7 plus or minus 5.2. The correlation coefficients between the angle of scoliosis and each of the following were significant: TLC (-0.548), percent predicted TLC (-0.547), VC (-0.485), percent predicted VC (-0.523), FRC (-0.533), percent predicted FRC (-0.338), RV (-0.438), and percent predicted RV (-0.318). The mean compliance of the total respiratory system (Crs) was 0.049 litter/cm H2O plus or minus SEM 0.004, and the mean compliance of the chest wall (Ccw) was 0.080 liter/cm H2O plus or minus SEM 0.012. The Crs and Ccw were inversely proportional to the angle (r-0.620 and -0.721) and directly proportional to the height and the weight. The mean deltaV/deltaPco2 was 1.32 liter/min per mm Hg (SEM 0.171), and the mean deltaVt/deltaPco2 was 28.9 ml/mm Hg (SEM 3.64). The correlation coefficients between deltaV/deltaPco2 and the following were height, 0.499; VC, 0.792; TLC, 0.632; AND Crs, 0.520; and between the deltaTt/deltaPco2 and the following were height, 0.500; VC, 0.878; TLC, 0.802; and Crs, 0.590. We conclude that body size and the deformity were the determinants of the lung volumes and the mechanical properties of the respiratory system, and that these variables were the major factors in both the magnitude and pattern of the ventilatory response to CO2. The correlations between age and the mechanical properties of the respiratory sytem, deltaV/deltaPco2, and deltaVt/deltaPco2, were not significant, but the correlation coefficients between age and several of the derivatives of deltaV/deltaPco2 and deltaVt/deltaPco2 were significant.
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PMID:Idiopathic scoliosis. Mechanical properties of the respiratory system and the ventilatory response to carbon dioxide. 113 65

Since previous studies from this laboratory have demonstrated that the redistribution of blood volume and concomitant relative central hypervolemia induced by water immersion to the neck causes a profound natriuresis and a suppression of the renin-aldosterone system, it was of interest to assess whether the diuresis induced by immersion was mediated by an analogous inhibition of ADH. The effects of water immersion on renal water handling and urinary ADH excretion were assessed in 10 normal male subjects studied following 14 h of overnight dehydration on two occasions, control and immersion. The conditions of seated posture and time of day were identical. During control ADH persisted at or above prestudy values. Immersion resulted in a progressive decrease in ADH excretion from 80.1 plus or minus 7 (SEM) to 37.3 plus or minus 6.3 muU/min (P smaller than 0.025). Cessation of immersion was associated with a marked increase in ADH from 37.3 +/- 6.3 muU/min to 176.6 +/- 72.6 muU/min during the recovery hour (P smaller than 0.05). Concomitant with these changes urine osmolality decreased significantly beginning as early as the initial hour of immersion from 1044 +/- 36 to 542 +/- 66 mosmol/kg H2O during the final hour of immersion (P smaller than 0.001). Recovery was associated with a significant mean increase in Uosm of 190 +/- 40 mosmol/kg H2O over the final hour of immersion (P smaller than 0.001). The suppression of ADH occurred without concomitant changes in plasma tonicity. These studies are consistent with the suggestion that in hydrated subjects undergoing immersion suppression of ADH release contributes to the enhanced free water clearance, which has been previously documented.
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PMID:Suppression of ADH during water immersion in normal man. 114 Nov 16

A modification to the vacuum system of a JSM2 scanning electron microscope has enabled hydrated specimens to be placed inside the specimen chamber of the instrument and to be surronded by water vapour at a pressure up to approximately I 3-kPa (10 Torr). The surface topography was observed by detecting the backscattered electrons using a wide angle backscattered electron detector placed close to the specimen. The microscope was operated in the normal scanning mode which allowed the examination of the surface topography of the specimens, whilst still retaining the depth of focus which is a feature of the SEM. This modification has enabled a resolution of approximately 0.2 mum to be obtained from biological specimens partially immersed in water at temperatures just above 0 degrees C.
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PMID:A wet stage modification to a scanning electron microscope. 117 4

We studied salt and water absorption in isolated rabbit superficial proximal straight tubules perfused and bathed with solutions providing oppositely directed transepithelial anion gradients similar to those which might obtain in vivo. The perfusing solution contained 138.6 mM Cl- 3.8 mM HCO-3 (pH 6.6) while the bathing solution contained 113.6 mM Cl- and 25 mM HCO-3 (pH 7.4); the system was bubbled with 95% O2-5% CO2. At 37 degrees C, net volume absorption (Jv nl min-1 mm-1) was 0.32 +/- 0.03 (SEM); Ve, the transepithelial voltage (millivolts; lumen to bath), was +3.1 +/- 0.2. At 21 degrees C, Ve rose to +3.7 +/- 0.1 and Jv fell to 0.13 +/- 0.01 (significantly different from zero at P less than 0.001); in the presence of 10(-4)M ouabain at 37 degrees C, Ve rose to +3.8 +/- 0.1 and Jv fell to 0.16 +/- 0.01 (P less than 0.001 with respect to zero). In paired experiments, the ouabain- and temperature-insensitive moieties of Jv and Ve became zero when transepithelial anion concentration gradients were abolished. Titrametric determinations net chloride flux at 21 degrees C or at 37 degrees C with 10(-4) M ouabain showed that chloride was the sole anion in an isotonic absorbate. And, combined electrical and tracer flux data indicated that the tubular epithelium was approximately 18 times more permeable to Cl- than to HCO-3. We interpret these results to indicate that, in these tubules, NaCl absorption depends in part on transepithelial anion concentration gradients similar to those generated in vivo and in vitro by active Na+ absorption associated with absorption to anions other than chloride. A quantitative analysis of passive solute and solvent flows in lateral intercellular spaces indicated that fluid absorption occurred across junctional complexes when the osmolality of the lateral intercellular spaces was equal to or slightly less than that of the perfusing and bathing solutions; the driving force for volume flow under these conditions depended on the fact that sigmaHCO3 exceeded sigmaCl.
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PMID:A component of fluid absorption linked to passive ion flows in the superficial pars recta. 118 77

Three urinary excretion tests of vitamin B12 absorption were done in 12 patients with classic pernicious anemia. The 24-hour urinary excretion of radioactivity was 2.1% +/- 0.7% (mean +/- SEM) of the ingested dose of cyanocobalamin-57 Co. When cyanocobalamin-57 Co was mixed with hog intrinsic factor in water, excretion increased to 15.6% +/- 1.6%. When cyanocobalamin-57 Co and intrinsic factor were given in two separate capsules, which is now a frequent practice, excretion was 9.5% +/- 2.2%. In 6 patients, use of the results obtained with capsules could have led to an incorrect diagnosis. When cyanocobalamin-57 Co and intrinsic factor are given in separate capsules, binding of radioactive vitamin to intrinsic factor may be incomplete due to inadequate mixing in the stomach or to binding of intrinsic factor to blocking antibody in the gastric juice. The classic technique in which intrinsic factor and cyanocobalamin-57 Co are mixed in water before administration should be used.
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PMID:Spurious Schilling test results obtained with intrinsic factor enclosed in capsules. 120 May 29

Studies were conducted in vitro to determine the permeability characteristics of the rabbit and dog pericardium. The hydraulic conductance (Lp), which was significantly higher than other tissue, was 1.6 +/- 0.19 X 10(-4) and 1.78 +/- 0.18 X 10(-4) g-cm-2-min-1-cm H2O-1 (mean +/- SEM), respectively, for the rabbit and dog pericardium. For various solutes, the permeability coefficient (P) of the pericardium for the rabbit was: 1.40 +/- 0.10 X 10(-4) cm-s-1 for water, 0.50 +/- 0.03 X 10(-4) cm-s-1 for glucose, and 0.73 +/- 0.005 X 10(-4) cm-s-1 for albumin. The reflection coefficient, sigma, for various solutes was: glucose 8.89 +/- 0.86 X 10(-4), sucrose 15.7 +/- 1.5 X 10(-4), dextran (molecular weight 40 000) 0.39 +/- 0.03, albumin 0.42 +/- 0.05, and for haemoglobin 0.58 +/- 0.06. These results, which indicate that the pericardium offers little resistance to the bulk transfer of liquids and to the passage of large molecules, are discussed as possible safety factors during pericardial effusion.
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PMID:An evaluation of the pericardial sac as a safety factor during tamponade. 120 11


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