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)

Human cadaver eyes can be dehydrated by prolonged elevation of intraocular pressure (three to five hours) or by hyperosmotic Dextran over a 20- to 30-minute period. We divided four pairs of donor eyes into two groups (A and B) and dehydrated four corneas by each method. After corneal thinning to 500 to 600 microns, central corneal pachymetry was measured every ten minutes during the rehydration period for one hour, with each cornea pair being moistened at a different rate (every 30 seconds, 1 minute, 2.5 minutes or 5 minutes). The resultant increase in central corneal thickness noted by change in pachymetry (delta P) ranged from 12.4% to 14.7% over one hour between the two groups. delta P did not differ significantly between groups A and B, regardless of the varying rate of balanced salt solution irrigation of the corneas. Thus, it appears that either method of corneal dehydration provides comparable stability of corneal thinning for at least one hour to allow consistent corneal dynamics for experimental refractive surgery.
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PMID:Human cadaver corneal thinning for experimental refractive surgery. 248 49

Geometrically based formulas for lathing aphakic epikeratophakia lenses have been simplified to enable easy calculation of the radii of cut for the optical and the wing zones. The formulas compensate for postoperative thinning of the lens on host cornea and allow for any desired amount of pre-lathing dehydration. Clinical results to date show that over 80% of lenses are made within 3 diopters of the expected power.
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PMID:Simplified formulas for lathing aphakic epikeratophakia lenses. 272 49

Preservation solutions for short-term storage of isolated donor corneas for use in penetrating keratoplasty have all been based on tissue culture medium, on the assumption that media designed to maintain the viability of cells at physiological temperatures will also provide suitable conditions for preservation at reduced temperatures. But for hypothermic preservation of some other tissues and organs, when ionic pumps are inhibited, it is unnecessary to support metabolism, and beneficial control of ion and water distribution between intra- and extracellular compartments is achieved by storage in appropriately formulated 'intracellular-type' solutions. We have therefore designed a solution that will restrict ionic imbalances and minimise endothelial cell swelling in corneas during exposure at reduced temperatures. This potassium-rich solution contains the biological pH buffer TES as an impermeant anion and is designated CPTES (corneal-potassium-TES). The structural and functional integrity of rabbit corneas stored at 0 degrees C in CPTES, without the addition of colloid osmotic agents, is compared with that of corneas stored in glutathione bicarbonate Ringers' solution (GBR), an 'extracellular-type' medium formulated for the maintenance of endothelial integrity during in-vitro perfusion at 34 degrees C. Corneas swelled significantly less during storage in CPTES than in GBR and could be stored for five days before reaching the same degree of hydration as corneas stored for only three days in GBR. Gross structural integrity and endothelial ultrastructure were maintained during storage for three and five days in CPTES. The rate of thinning of corneas stored in CPTES was significantly greater than in comparable groups of corneas stored in GBR. However, the efficient dehydration of corneas stored in CPTES was always preceded during perfusion by a brief period of additional swelling which was shown to be an osmotic response during the elution of the buffer compound TES that had permeated the stroma during storage. The omission of calcium or the addition of adenosine and glutathione to the CPTES preservation medium had no detectable effect on the integrity of the endothelium, but the omission of bicarbonate was beneficial, producing significantly higher rates of stromal thinning during normothermic perfusion. Additional benefits for extending storage by including colloid osmotic agents are described in a companion paper.
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PMID:Hypothermic preservation of corneas in a hyperkalaemic solution (CPTES): I. Short-term storage in the absence of colloid osmotic agents. 281 86

Cardiac depression in the isolated rat heart perfused with 4% ethanol was correlated with intracellular phosphate energetics and tissue water distributions. Energy metabolites were assessed using 31P magnetic resonance spectroscopy (MRS) and correlated to the mitochondrial redox state using epicardial surface fluorometry. Changes in myocardial water compartmentation were measured by using 1H NMR spectroscopy with an extracellular chemical-shift reagent (DyTTHA) and correlated to results of 2D echocardiography (2DE). During alcohol perfusion there was a significant decrease in developed pressure and in coronary flow. No change was seen in ATP, PCr, pHi, Pi, or NADH. After withdrawal of alcohol from the perfusate cardiac function reverted to control values without a depletion of energy levels. During alcohol perfusion 1H MRS showed a marked redistribution of water from the intra- to the extracellular space, corresponding to a 35% left ventricular wall thinning confirmed by 2DE. The results indicate that acute alcohol cardiac depression is related to a dehydration of myocardial cells, but is not associated with intracellular acidosis or energy depletion.
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PMID:31P and 1H magnetic resonance spectroscopy of acute alcohol cardiac depression in rats. 317 69

In seven calves we studied experimental invasions by sporocysts of the Sarcocystis cruzi (S. bovicanis) species, isolated from faeces of dingo dogs. Out of clinical changes, an increase in body temperature to 39.6 to 40.5 degrees C is characteristic in the fourth to the eighth week of disease, relaxed attitude of animals, progressive thinning down, anaemia of mucous membranes, diarrhoea and total dehydration. The post-mortem examination completes this observation with generalized hyperplasia of lymphatic nodes to haemorrhagic lymphadenitis and small petechial haematomata on serous coats, particularly on epicardium. Schizonts in the endothelium of capillaries in various organs were evaluated as specific lesions, demonstrated within 26 days from invasion in one calf. From 46 days after invasion we found muscular cysts in three other calves. The titres of sera in all experimental calves obtained with the NFR method are also evaluated as specific. Invaded calves died gradually between the 26th and 59th day, control calves were slaughtered and no sarcocysts were found.
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PMID:[Development of sarcocystosis in experimentally infected calves]. 391 81

Gross, subgross and histological lesions were studied in 103 pigs infected with transmissible gastroenteritis virus and killed at daily intervals for 14 days. Twenty-three pigs served as controls. Thirty-six pigs were given colchicine four hours prior to being killed in order to determine the mitotic activity in the gastrointestinal tract. The gross lesions consisted of dehydration, excessive milk curd in the stomach, focal hemorrhage in the submucosa of the diverticulum ventriculi of the stomach, fundic and pyloric congestion in severly dehydrated animals and thinning of the small intestinal wall. The major subgross lesion was a marked shortening of the villi in the lower duodenum, jejunum and ileum within 24 hours after exposure to the virus. Regrowth of the villi became evident on about the sixth day after infection. Histological examination of the small intestine revealed that the villus-height/crypt-depth ratio in the jejunum was reduced from 7:1 in normal pigs to less than 1:1 in infected pigs. Villous atrophy was less severe in the proximal duodenum and ileum. Cells covering the atrophic villi were flatened or cuboidal and did not have well defined brush borders. Inflammatory changes in the gastrointestinal tract were minimal at all stages of infection. Goblet cell numbers increased slightly in the recovery stage of the disease and small numbers of mononuclear cells accumulated in the lamina propria during regrowth of the villi. The number of metaphase nuclei in the small intestinal crypts of infected pigs was greater than in normal pigs.
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PMID:Lesions of the gastrointestinal tract of pigs infected with transmissible gastroenteritis. 423 92

The feasibility of using hydrogel lenticular implants of high water content to alter the anterior corneal curvature for purposes of refractive keratoplasty has been investigated in rabbits. Lenticules (6 mm in diameter) of Permalens (Perfilcon-A) were trephined from contact lens and implanted within an intralamellar pocket in the cornea. The in vitro glucose flux across the hydrogel (0.23 mm thick) was measured at 131 +/- 7 micrograms/cm(2)/hr. For clinical comparison, non-water-permeable disks of Teflon were also implanted. The Teflon implant caused an aseptic ulcer to develop anterior and central to the implant by 9 +/- 4 days. The hydrogel lenticular implant did not cause central ulceration during the 7 month postoperative follow-up. There was a thinning and eventual erosion of the stroma anterior to the edge of the hydrogel implant, 16 +/- 7 weeks. The glycogen contents of the epithelium anterior to (1) the sham operation, i.e., lamellar pocket dissection, (2) the implanted hydrogel lenticule with or without the presence of an erosion, and (3) the control corneas were statistically from the same population. Yet there was a slight dehydration of the stroma anterior to the hydrogel implant when compared to control tissue. A thin-edged implant lenticule design should overcome the stromal thinning caused by the thick-edge implants. During the short-term follow-up, the hydrogel lenticular implant proved to be successful as a refractive keratoplasty implant material.
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PMID:Refractive keratoplasty with intrastromal hydrogel lenticular implants. 725 Dec 94

We studied the depletion of the post-lens tear film as contributing to inferior arcuate staining with ultrathin high water content hydrogel lenses. We monitored the post-lens tear film specular reflection of hydrogel lenses (0.04 mm center thickness, 67% nominal water content), which caused inferior arcuate staining. A standard thickness (0.12 mm) lens was worn in the contralateral eye as a control condition. Lenses were worn for a 2 hour period by 20 subjects. Post-lens tear film appearances were categorized as amorphous, faint colored, or colored, where the colored patterns represented a relatively depleted post-lens tear film. We also measured lens dehydration, lens adherence, and pre-lens tear film stability in order to evaluate their role in inferior arcuate staining. The ultrathin and standard lenses caused staining in 100 and 75% of subjects, respectively; the severity of staining was much greater with the ultrathin lenses (Wilcoxon signed ranks test, P = 0.0004). The ultrathin lenses were associated with a higher incidence of post-lens tear film depletion (P = 0.018), had greater front surface dehydration (P = 0.0004), and were more adherent to the eye (paired t-test, P = 0.001). However, pre-lens tear thinning times were not significantly different between the two lens types (Wilcoxon signed ranks test, P > 0.05). These findings support the contention that post-lens tear film depletion is a component of a lens adherence or lens dehydration mediated mechanism of inferior arcuate staining.
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PMID:Role of the post-lens tear film in the mechanism of inferior arcuate staining with ultrathin hydrogel lenses. 758 76

In these studies we have investigated factors that might account for two previous observations of the ventral glial limitans subjacent to the supraoptic nucleus (SON-VGL) of dehydrated rats: (1) a reversible reduction in the thickness of the SON-VGL, and (2) a reversible reorientation of VGL astrocytes. Since components of the basal lamina influence both cell viability and polarity, we used electron microscopic sterology to determine the volume fraction of basal lamina in the SON-VGL. We further made extensive measurements of astrocytic process thickness to determine if cellular shrinkage is a factor in the thinning of the SON-VGL. While we found no evidence for changes in the thickness of astrocytic processes, there was a significant and reversible reduction in the extent of the basal lamina. These data suggest that the thinning of the VGL is due to complex biochemical events and is not merely an epiphenomenon of dehydration.
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PMID:Dehydration-associated changes in the ventral glial limitans subjacent to the supraoptic nucleus include a reduction in the extent of the basal lamina but not astrocytic process shrinkage. 1061 59

Dry eye is an ocular disease clinically associated with corneal epithelium damage and arises acutely or chronically from dehydration of the ocular surface. We provide herein a novel in vivo model of corneal epithelium damage, in which the corneal surface was entirely covered with a sugar powder to provoke the rapid removal of corneal surface liquid. In this animal model, such corneal damage as can be fluorometrically detected was observed immediately after 20-minute hyperosmotic treatment, reached a maximum 6 hours later, and then gradually declined to complete recovery at Hour 126. Recovery of the damaged corneas produced by hyperosmotic stress was significantly accelerated by treatment with 0.1% sodium hyaluronate, a dry eye remedy in Japan. Thinning or partial erosion of the epithelial cell layers was histopathologically demonstrated in and around the sugar powder-applied area but the posterior stromal cell layer remained intact, indicating that the present rabbit in vivo model may be used to conveniently screen therapeutics against acute ocular diseases with corneal epithelium damage. In addition, microscopic observations of TUNEL-stained thin-sections of the damaged corneas indicated that apoptotic cell death, but not any inflammatory reactions, may be at least partially responsible for the hyperosmolarity-induced destruction of the corneal epithelium.
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PMID:A convenient rabbit model of ocular epithelium damage induced by osmotic dehydration. 1282 46


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