Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0851184 (thinning)
 11,252 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

When the inner cylinder of a fluid-filled Couette viscometer is rotated rapidly, a vortical flow pattern develops when a dimensionless value referred to as the critical Taylor number (Tc) is reached. We have determined its magnitude in our viscometer for three Newtonian fluids and for blood at 37 degrees C, using the inflection point of torque/RPM vs. RPM (sudden rise in apparent viscosity). Its position was identified by least squares line fitting. Because blood was studied, the viscosity used in Tc calculation was the apparent bob shear stress/shear rate ratio at the inflection marking vortical flow onset. For glycerol-water mixtures Tc was 41.8 +/- 0.3 (N = 11), for propylene glycol 42.0 +/- 0.2 (N = 14), for silicone oil 41.8 +/- 0.2 (N = 11). For healthy blood Tc was 40.7 +/- 0.9 (N = 140). This evidence against blood's increased resistance to flow instability was accompanied by a slower rate of rise in torque both above and below Tc compared to the three Newtonian fluids. Newtonian fluids and blood both developed wavy vortical flow at a rotation rate moderately higher than Tc. Blood resisted this unstable flow behavior more than the Newtonian fluids but it also experienced a slower rate of rise in torque with increasing rotation rate above the critical Taylor number. Shear-thinning is the simplest explanation for blood's mildly altered Taylor vortex behavior; blood's resistance to flow instability is otherwise not found to be sufficient to affect its flow stability in man.
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PMID:Blood's critical Taylor number and its flow behavior at supercritical Taylor numbers. 366 98

The effects of long-term extended wear of soft contact lenses on the human cornea were determined by examining 27 patients who had worn a high water content hydrogel contact lens in 1 eye only for an average of 62 +/- 29 months (mean +/- SD). The other eye, which was either emmetropic or amblyopic, acted as a control. The lens-wearing eye showed a 14.8% reduction in epithelial oxygen uptake (P less than 0.001), a 5.6% reduction in epithelial thickness (P less than 0.05), a 2.3% reduction in stromal thickness (P less than 0.05), the induction of epithelial microcysts, and a 22.0% increase in endothelial polymegathism (P less than 0.001). Endothelial cell density was unaffected by extended lens wear. No interocular differences in any of these physiological characteristics were found in a matched control group of anisometropic and amblyopic subjects who did not wear contact lenses. The patients ceased lens wear for up to one month and recovery of corneal function was monitored during this period. Epithelial oxygen uptake and thickness recovered within 33 days of lens removal. The number of microcysts increased over the first 7 days, but decreased thereafter; some microcysts were still present 33 days after lens removal. Recovery from stromal thinning had not occurred after 33 days following lens removal. There was a slight reduction in polymegathism in some patients, but overall this was not statistically significant. These findings establish (1) that the extended wear of hydrogel lenses induces significant changes in all layers of the cornea; (2) that lens wear suppresses aerobic epithelial metabolism, which may compromise the epithelial barrier to infection; and (3) that changes to the stroma and endothelium are long-lasting. Lens-induced effects on corneal physiology can be minimized by fitting lenses that have greater oxygen transmissibility (are thinner), are more mobile, more frequently removed, and more regularly replaced.
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PMID:Effects of long-term extended contact lens wear on the human cornea. 386 8

Specular microscopy was used to measure thickness changes of stroma-endothelium preparations from rabbit corneas in vitro. The preparations were first bathed on both sides for 90 min with different bicarbonate-Ringer solutions (2 to 50 mM bicarbonate) maintained in equilibrium with 5% CO2-air (pH 6.2 to 7.9). During this equilibration, the stroma attained a stable thickness that was inversely related to the hydrostatic pressure (20 to 100 cm H2O) applied to the endothelial surface. After equilibration and at 20 cm H2O pressure, covering the anterior stromal surface with silicone oil (Dow Corning 200 dielectric fluid, 20 cs viscosity) resulted in stromal thinning. The rate of this deturgescence increased (from 5 to 75 micron/h) as the equilibration solution bicarbonate level increased from 2 to 30 mM. The net size of the thickness change was also related to the equilibration bicarbonate level. However, indirect studies on the cornea using phenol red indicator and pH electrode measurements of solutions revealed that the stromal bathing solutions became more alkaline under the silicone oil layer. CO2 is soluble in silicone oil. Implications of these CO2 and pH effects on mechanisms of corneal deturgescence are discussed.
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PMID:New observations on bicarbonate-pH effects on thickness changes of rabbit corneas under silicone oil in vitro. 393 62

Renal physiological and morphological adjustments to a reduced protein diet were studied in young Munich-Wistar rats. Two groups of animals were used for the correlative physiological-morphological studies: normal protein (NP, 24% dietary protein) rats and reduced protein (LP, 8% dietary protein) rats. Both groups were fed their respective diets for 4-5 wk and had free access to drinking water. Physiological measurements of GFR and urea clearance were made on five animals from each group. These data showed that the changes in renal function specifically and almost exclusively affected the handling of urea. There was no difference in GFR between the NP and LP rats. Urea clearance was substantially reduced in LP rats. Morphological analyses were made on perfusion-fixed kidneys of five animals from each group. Selected slices were examined and photographed by light and electron microscopy. These data showed no difference in size and number of elements within the vascular bundles but showed significantly smaller lumina of the thin limbs of the short-looped nephrons and a significant thinning of the wall of the thin descending limbs of the long-looped nephrons. These morphological changes may in part be responsible for the observed physiological adjustments to a reduced protein diet. An additional group of rats (6 NP and 5 LP, all dehydrated) were analyzed for distribution of solutes within the inner medulla. The data showed that the concentration of urea, but not that of Na+, was reduced at the papillary tip in LP rats.
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PMID:Physiological and morphological responses of the rat kidney to reduced dietary protein. 397 Jan 63

The endothelial pump and evaporation components of corneal recovery were studied in the in vivo human cornea by inducing corneal swelling with the use of hypoxia and monitoring the subsequent decrease in corneal thickness. Corneal recovery follows a nonlinear time course with the rate of recovery decreasing as the cornea thins. Following 60 micron of induced edema, recovery with the eyes open required an average of 2.5 hr to reach baseline corneal thickness, while recovery with the eyes closed took an average of 4.0 hr to reach the normal physiologic corneal swelling (17 micron). Our analysis indicates that for open eye recovery from 60 micron of swelling, the endothelial pump provides 20%, while the osmotic thinning caused by tear evaporation contributes 80% of recovery. During recovery, the rate of water evaporation from the anterior corneal surface remained relatively steady at 2.5 microliter/cm2 X hr. Comparison of measured vs calculated recovery rates during recovery with the eyes closed suggests that the endothelial pump functions at one speed and that the "pump-leak" theory of corneal hydration control is applicable for the human cornea.
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PMID:In vivo assessment of mechanisms controlling corneal hydration. 400 95

The chronic toxicity of a new topical glucocorticoid, difluprednate (DFBA) was studied in Beagle dogs. DFBA ointment (0.05%) was percutaneously treated to the back of dogs at daily doses of 125, 12.5 and 1.25 micrograms/kg for 6 months. The local effects of DFBA In the treated area, thinning of the skin and inhibition of the fur-growth were observed with scale and erythema. The skin showed histological atrophy of the epidermis, a decrease of the adipose tissue and atrophy of the adnexa. These changes returned to normal after the 2-month withdrawal period. The systemic effects of DFBA In the 125 micrograms/kg group, the following changes were observed, although neither death nor severe symptoms occurred: General observations were seen an increase of water intake and urinary volume. A decrease of lymphocytes and eosinophils, and an increase of neutrophils were observed in the hematological examination. There were high sodium and low potassium levels, and an increase of alkaline phosphatase and gamma-glutamyltranspeptidase activities in the biochemical examination. The organ weights showed a decrease of the thymus, adrenals, prostate and ovaries, and an increase of the liver and kidney. An atrophy of the lymphatic tissues and adrenal cortex, retardation of the sexual maturation, glycogen deposit in the hepatic cells, slight degeneration of the renal tubuli, and slight thinning of the sternum and non-treated skin were noted in the pathological examination. These changes returned to normal after the 2-month withdrawal period. In the 12.5 micrograms/kg group, the atrophic changes in the thymus, adrenal and non-treated skin appeared slight. In the 1.25 micrograms/kg group, no changes were found. Conclusively, all the local and systemic changes observed by DFBA in this study were due to the already known pharmacological effects of glucocorticoids. It is considered that a 12.5 micrograms/kg dosage is similar to a non-effect dose.
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PMID:[Chronic toxicity study on difluprednate in dogs]. 403 1

Chronic toxicity study of halopredone acetate (THS-201), a synthetic corticosteroid, was carried out using Jcl: Wistar rats. THS-201 was subcutaneously administered to the rat in doses of 0.02, 0.1, 0.5 and 2.5 mg/kg/day, with the periods for administration and recovery being 12 and 2 months, respectively. In the group of THS-201 2.5 mg/kg, the below findings were observed: thinning of lumbar hair, suppression in body weight gain, decrease of food consumption in both sexes and decrease of water consumption in male. The lesions to lymphatic system were indicated by the examinations of hemogram, organ weight and histopathology. A few changes in urinary and biochemical values were seen, and foreign body granuloma was observed in the injected subcutis. After 2 month-recovery period, above-mentioned findings almost disappeared. In the group of THS-201 0.5 mg/kg, some of the changes were noted slightly and disappeared after the recovery period. In the groups of THS-201 0.1 and 0.02 mg/kg, any toxic changes attributable to THS-201 were not observed. It was concluded that the non-toxic dose and the defined toxic dose of THS-201 in this study were 0.1 and 0.5 mg/kg/day, respectively.
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PMID:[Study on toxicity of halopredone acetate. (III). Chronic toxicity study in rats]. 406 62

Histochemical studies of the rat epididymis after treatment with alp ha-chlorohydrin (U-5897) are presented. 14 sexually mature male rats received either daily subcutaneous injections of 50 mg U-5907/kg body weight or distilled water for 20 days. The animals were sacrificed the day following the last injection. U-5897 induced temporary sterility as demonstrated by blocked transport of spermatozoa, and spermatogenic cells eliminated from the spermatogenic epithelium which became blocked in the caudal part of the epididymis. This resulted in the distension of the segment of the distal part of the epididymal duct and to the thinning of the epithelium which lined the altered segment. Alkaline and acid phosphatases, nonspecific esterases, succinate and glucose-6-phosphate dehydrogenases and reduced nicotinamide-adenine dinucleotide tetrazolium reductase in the unchanged part of the epididymal duct were comparable to control rats whereas the altered part of the epididymis showed these activities to much weaker degrees or to be absent altogether.
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PMID:Histochemical studies of the rat epididymis after treatment with alpha-chlorohydrin (U-5897). 415 41

Male strains of the water mold Achlya ambisexualis produce antheridial hyphae in response to the steroid hormone antheridiol. The antheridial hypha is postulated to be initiated through a localized wall softening with the enzyme cellulase. Freeze-etch studies of hormone-treated hyphae were conducted to determine if aggregates of vesicles are induced at the location of new antheridial hyphae. Localized aggregates of vesicles were found in conjunction with areas of wall thinning. These data suggest that the processes of vesiculation and secretion provide a mechanism for concentration of cellulase at the site of initiation of antheridial hyphae.
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PMID:Sexual morphogenesis in Achlya: ultrastructural basis for the hormonal induction of antheridial hyphae. 452 41

1. The effect of dietary restriction (sufficient to produce a loss of about 32% of initial body weight) on intestinal active transport has been studied in the rat by the use of sacs of everted mid-small intestine. Eight D-sugars, four L-sugars and two D-amino acids were employed.2. Dietary restriction enhanced the normally occurring active transport of D-galactose, 3-O-methyl-D-glucose and D-methionine. In addition, sacs of dietary-restricted small intestine were able to concentrate in the serosal fluid D-fucose, D-xylose and D-histidine, which sacs of normal rat intestine could not do. The final (1 hr) serosal/mucosal concentration ratios produced for these actively transported substances were independent of net water movement.3. Sugars which were not concentrated in the serosal fluid of sacs of fully fed or dietary-restricted intestine were D-arabinose, D-fructose, D-glucosamine, D-mannose, L-arabinose, L-fucose, L-sorbose and L-xylose.4. The characteristics of D-fucose and D-xylose active transport suggest that they are transported by the mechanism which actively transports D-glucose. The comparatively low content of D-glucose in dietary-restricted intestine, compared with fully fed intestine, may be part of the explanation for observable active transport of D-fucose and D-xylose by dietary-restricted sacs.5. Thinning of the intestinal wall is believed not to be the cause of the enhanced active transport found during dietary restriction.6. The results show that dietary-restricted rat small intestine may, at times, be more useful than fully fed rat small intestine in the study of intestinal active transport.
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PMID:The use of dietary-restricted rat intestine for active transport studies. 534 15


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