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)

Fifty organisms of Pseudomonas aeruginosa were injected intralamellarly in both eyes of 60 albino rabbits. Twenty-four hours later, all eyes were graded and stratified into six groups of ten rabbits with equivalent infections. Treatment was begun with gentamicin alone or 0.3% polymyxin B alone, and in combination with acetylcysteine, 0.3M edetate disodium, and 2.500 units/ml of heparin sodium, four times daily. We also compared topical colistin and colistin and topical heparin. After two weeks, those corneas treated with polymyxin B and topical heparin showed a reduction in ulceration, corneal thinning, and descemetocele formation compared to those treated with polymyxin B alone. Based on these studies, heparin was administered topically, four times daily, to three patients with Pseudomonas-induced corneal ulcers in addition to antibiotics. Before treatment all corneas showed evidence of corneal liquefaction and two of the corneas were in imminent danger of perforation. After therapy, no corneas perforated; one patient recovered visual acuity of 6/9 (20/30), one patient recovered visual acuity of 6/6 (20/20) after keratoplasty, and the third has a vascularized leukoma.
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PMID:Therapeutic effects of heparin on Pseudomonas-induced corneal ulceration. 18 11

The effect of various additives, electrolytes and non-electrolytes, on the cloud point of non-ionic surfactants has been studied. Additives which salt-out the polyoxyethylene chains of the surfactants cause decreased stability of oil-in-water emulsions by decreasing the true hydrophile-lipophile balance (HLB) of the surfactant; additives such as sodium iodide and propanol salt-in the non-ionic surfactants and result in an increase in the effective or true HLB of the system. The latter additives do not increase the hydration of the polyoxyethylene chains but their effect must be on the structure of water so that the heat of hydration of the chains is altered. Experiments with free films of the aqueous surfactant (Brij 96) show that thinning rates are markedly affected by the additives, but there is little effect on the equilibrium thickness of the films (ca 11 nm). Nonetheless the thickness at the transition from thick film to equilibrium black film decreases with increasing cloud point of the solution indicating increased stability. The importance of structure formation in the liquid film separating the emulsion globules was demonstrated.
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PMID:Emulsion stabilization by non-ionic surfactants: the relevance of surfactant cloud point. 23 85

Keratoconus is a disease that results in thinning and ectasia of the central cornea. Cultures of corneal stromal cells from patients with keratoconus were established and the synthesis of glycosaminoglycans compared with the synthesis of glycosaminoglycans by normal human corneal stromal cells in culture. Keratoconus and normal control cell cultures were incubated with sodium [(35)S]sulfate and [(3)H]glucosamine for 4 h. After incubation, the labeled glycosaminoglycans were isolated from the medium fractions and cells. Keratoconus and normal control cultures synthesized similar amounts of sulfated glycosaminoglycans independent of the age of donors and(or) the number of subcultures. In contrast to normal control cultures, most of the newly synthesized glycosaminoglycans produced by keratoconus cells were found in the growth medium and much less were in the cell layer. Treatment with glycosaminoglycan-degrading enzymes followed by paper chromatography showed that keratoconus cells, as normal control cells, produced hyaluronic acid and various sulfated glycosaminoglycans. The production of cell layer-related heparan sulfate was markedly reduced in keratoconus cultures. Because heparan sulfate has been shown to be associated with cell surfaces, the decreased heparan sulfate content could reflect changes at this location.
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PMID:The synthesis of glycosaminoglycans by cultures of corneal stromal cells from patients with keratoconus. 43 19

1. Low levels of insuling stimulate transendothelial fluid transport from preswollen stroma to aqueous in rabbit corneal preparations. The rate of stromal thinning at the end of the first hour averages 30% faster with insulin, 3.5 x 10(-22) M (4.8 micromicron/ml.), than that of the paired control. This concentration is about the physiological level in rabbit aqueous. 2. The stimulation with insulin is transient. Rates of thinning average higher but not significantly different from control rates by the second hour. 3. High levels of insulin between 3.5 x 10(-9) M (480 micromicron/ml.) and 2.0 x 10(-6) M (2.75 X 10(5) micromicron/ml.) inhibit fluid transport. The inhibition at the low end of this range of concentrations becomes more pronounced with longer perfusion times but appears not to exceed ca. 50% of the control rate. 4. Ouabain also induces a biphasic effect on fluid transport which is characteristically different from that with insulin. The maximal stimulation observed at all times occurred with a fixed concentration of 10(-10) M. The stimulation is not transient but increases throughout the duration of the perfusion; the average rate is elevated 50% above the control rate by the third hour. 5. The transition from a stimulatory to an inhibitory effect occurs consistently at ca. 10(-8) M with ouabain, while a similar transition with insulin occurs at ca. 10(-9) M and appears to shift towards slightly higher concentrations during a 3 hr perfusion period. 6. Inhibition of fluid transport with ouabain, 3 x 10(-7) M, is increased from ca. 50% after 1 hr to more than 70% at the end of the third hour of perfusion. 7. The combined presence of stimulatory concentrations of ouabain and insulin affects tromal thinning in a manner resembling the effect of ouabain alone more than that of insulin; additive effects could not be discriminated. Progressively raising the concentration of insulin to a level (10(-8) M) that alone inhibits stromal thinning, ultimately abolishes the stimulatory effect of ouabain. Based on other evidence and current models of drug/hormone-membrane interaction, these results can be interpreted to indicate a concentration-dependent interaction between receptor complexes of ouabain and insulin with (Na+ + K+)-ATPase.
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PMID:Biphasic effects of insulin and ouabain on fluid transport across rabbit corneal endothelium. 63 30

To evaluate the influence of glucose infusate administered with insulin and potassium on left ventricular function during 4 h of ischemia, as well as mechanism of action, four groups of intact anesthetized dogs were studied. Acute regional ischemia was induced with a balloon tip catheter in the left anterior descending artery and infusates were begun after 20 min of ischemia. A threefold increase of plasma glucose concentration was associated with improved left ventricular function during ischemia, compared to animals receiving isovolumic saline. There was a significant decline of left ventricular end-diastolic pressure associated with elevation of stroke volume and ejection fraction to control levels, as determined by indicator dilution. In a separate subgroup studied by cineangiography, shortening of the ischemic anterior wall, after an initial decline, was increased in response to glucose but there was no evidence of extension of injury. Ischemic tissue exhibited a smaller gain of water as well as Na+ per gram dry weight as compared to ischemic controls. On precordial electrocardiogram mapping there was a significant decrease in the sigmaST (sum of ST elevation) as well as NST (number of ST segment elevations), but the reduction of R wave amplitude was not different from controls. To further evaluate long-term effects, eight controls and six treated animals underwent myocardial ischemia and were sacrificed after 4 mo. Calculated area and weight of scar, as well as degree of wall thinning, were similar in both groups. The glucose-treated animals had a significant decrease of plasma FFA in contrast to controls which manifested a significant rise. To examine the postulate that the decrease in FFA was important to therapeutic action, a third group was infused with Intralipid (Cutter Laboratories, Inc., Berkeley, Calif.) and heparin, simultaneously with the glucose infusate, to effect an elevation of plasma FFA during ischemia. Changes in myocardial function and electrolyte composition, as well as precordial electrocardiogram mapping, were similar to that of animals receiving glucose alone. Because serum osmolality was increased approximately 40 mosmol during the glucose infusion, the potential role of hyperosmolality was assessed by infusion of 20% mannitol during acute ischemia in a fourth group. After a transient small increase, there was a moderate decline in function by 4 h, suggesting that the response to glucose is not dependent upon extracellular osmolality. Thus, it is concluded that during the initial hours after the onset of myocardial ischemia the glucose infusate improves ventricular performance without evidence of arrhythmia induction or intensification of ischemic injury. Evolution of irreversible necrosis appears to be delayed rather than prevented under the circumstances of this study.
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PMID:Sustained effect of glucose-insulin-potassium on myocardial performance during regional ischemia. Role of free fatty acid and osmolality. 65 87

The mechanism and characteristics of intestinal absorption of arachidonic acid were studied in vitro using everted intestinal sacs of the rat. Arachidonic acid absorption was studied at concentrations of 5 micron to 8.36 mM. The plot of absorption rate vs. concentration fitted best to a rectangular hyperbola at low micron concentrations and to a straight linear relationship in the mM range of concentrations. Metabolic inhibitors and uncouplers did not change absorption in either range of concentrations. The absorption of arachidonic acid increased with thinning of the unstirred water-layer, decrease in the pH, or the substitution of sodium taurocholate by Pluronic F 68 OR Tween 80. Absorption decreased following the equimolar additions of oleic, linoleic, and linolenic acids. Absorption rate did not change when the taurocholate concentration was varied from 5-15 mM or following the additions of butyric or glutamic acids, leucine, lysine, or dextrose. It was concluded that arachidonic acid is absorbed by a concentration-dependent dual mechanism of transport which is not energy dependent. At the low micron range of concentrations, facilitated diffusion is predominant, while at mM concentrations, simple diffusion is the dominant mechanism of absorption. Changes in the intestinal fluid composition, flow rate, and pH can modify the rate of absorption of arachidonic acid.
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PMID:Arachidonic acid intestinal absorption: mechanism of transport and influence of luminal factors of absorption in vitro. 71 12

Intestinal absorption and intraluminal pressures were measured at perfusion rates between 0.3 and 200 ml per min in the rat ileum in vivo. Glucose absorption from a 72 mM glucose solution and tritiated water ([3-H]water) diffusion rate were used to reflect changes in mucosal surface area. Glucose absorption from a 4 mM solution was used to indicate changes in unstirred water layer thickness, and mannitol and urea absorption were used as markers of passive mucosal permeability. In a partially obstructed intestinal segment, designed to keep the gut partially filled even at low perfusion rates and to minimize surface area change as perfusion rate was increased, glucose absorption from a 4 mM solution increased by 150% as perfusion rate was increased from 1 to 100 ml per min. Forty per cent of this increase was due to increased surface area (estimated from the change in [3-H]water absorption), and 110% of the increase is attributed to thinning of the unstirred water layer. Because mannitol absorption was zero at all perfusion rates, none of the enhanced glucose absorption rate need be attributed to enhanced mucosal permeability, even though intraluminal pressure was increased at higher perfusion rates. Urea absorption was apparently influenced by surface area and by permeability changes, but not by the thickness of the unstirred water layer. This model was also used to explore the effect of unstirred water layer thickness on the inhibitory effect of sodium replacement by magnesium on glucose absorption from a 4 mM glucose solution. Inhibition by sodium removal was equal at 1, 10, 100, and 200 ml per min perfusion rates, suggesting that unstirred water layer thickness does not play an important role in the interaction of glucose and sodium absorption when intraluminal sodium concentration is reduced. Additional experiments in an unobstructed ileal segment revealed that the major effect of enhanced perfusion rate is to increase mucosal surface area; relatively high rates of perfusion were required to thin significantly the unstirred water layer when intestinal outflow was not partially obstructed.
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PMID:Effect of perfusion rate on absorption, surface area, unstirred water layer thickness, permeability, and intraluminal pressure in the rat ileum in vivo. 113 32

Patients with medically intractable temporal lobe epilepsy (TLE) undergo medial temporal lobectomy with hippocampectomy for one of two reasons. (1) A lesion (tumor or arteriovenous malformation) adjacent to, but not invasive of, the hippocampus, results in the removal of the lesion and adjacent hippocampus in order to ensure a tumor-free margin. This group will be referred to as tumor-related TLE (TTLE) patients. (2) The operation is performed when depth electrode recordings and other evaluative techniques point to the hippocampus as the focus of seizure initiation. This group will be referred to as cryptogenic TLE (CTLE) patients. Analysis of the hippocampi of these two groups of patients reveals that the TTLE hippocampus is quite similar to that of autopsy subjects in its chemical neuroanatomy. However, the dentate gyrus of the CTLE patients shows considerable morphological and cytochemical reorganization. This reorganization is characterized by a number of features. (1) There is a loss of granule cells which occurs either as a patchy loss and/or a thinning of the granule cell layer. (2) Remaining granule cells which contain dynorphin appear to produce recurrent collaterals into the inner molecular layer of the dentate gyrus. (3) In the subgranular region of the hilus (the polymorphic layer) there is a selective loss of interneurons immunoreactive for somatostatin, neuropeptide Y and substance P. (4) There appears to be an increase in fibers immunoreactive for somatostatin and neuropeptide Y which extend throughout the dentate molecular layer. Somatostatin fibers being less numerous than neuropeptide Y fibers (5). The distributions of a number of neurotransmitter receptors also show striking reorganization in the dentate gyrus of the CTLE hippocampus. (6) Second messenger systems protein kinase C and adenylate cyclase, and Na+, K(+)-ATPase activity, as determined by ouabain binding, is increased in the molecular layer of CTLE. This remodeling of the CTLE hippocampus may hold the key to the mechanisms of hyperexcitability of the granule cells in the hippocampus of this group, and consequently the generation of seizures. The removal of the hippocampus in CTLE patients results in good control of seizures, whereas removal of hippocampi that do not show such reorganization, in a group of patients classified as atypical CTLE patients, results in inadequate seizure control. These findings suggest a complex series of processes in converting the properly regulated granule cells into hyperexcitable ones.
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PMID:Neurotransmitters and their receptors in human temporal lobe epilepsy. 136 31

The surfactant delmopinol, which is a new antiplaque agent with a low anti-microbial profile, was tested for its effects on the viscosity of bacterial extracellular glucans. Glucans were isolated from Streptococcus mutans broth supernatants incubated with 0.15 M sucrose in 50 mM sodium phosphate buffer at pH 6. The viscosity was measured in a shear rate range from 15 to 230 reciprocal seconds. The viscosity of the water-soluble glucan was found to be independent of shear rate whereas the water-insoluble glucan showed a strong shear thinning. The addition of delmopinol to preformed glucans did not affect the viscosity nor the shear rate dependence of the glucans. However, when present during synthesis of the polysaccharides, delmopinol was found to reduce the viscosity of both water-soluble and water-insoluble glucans by approximately 50% at the shear rates investigated. The reduction in viscosity for the water-soluble glucans was obtained at a delmopinol concentration of 0.32 mM (0.01%) and for the water-insoluble glucans at 3.2 mM delmopinol. The observed reduction of viscosity of glucans indicates that the in vivo stability of plaque matrix after delmopinol treatment would be lowered, which may lead to a reduction of plaque cohesion and thus facilitate mechanical plaque removal.
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PMID:Effect of delmopinol on the viscosity of extracellular glucans produced by Streptococcus mutans. 142 43

1. We applied morphological, pharmacological, electrophysiological, and computer simulation techniques to analyze the origin of impulse initiation in amphibian retinal ganglion cells. 2. Morphological studies of retinal ganglion cells in the mudpuppy (Necturus maculosus) and larval tiger salamander (Ambystoma tigrinum) were carried out with the use of either retrograde or intracellular labeling with horseradish peroxidase. These studies identified a characteristic thinning of the axon that begins after the initial segment of axon emerges from the ganglion cell soma or primary dendrite. Morphometric analysis of the thin segment revealed an average length of 74 microns with a standard deviation of 22 microns. For 20 conventionally placed ganglion cells, the length of the thin segment could not be correlated with soma size, initial segment diameter, or distance from the optic disk. There was also little or no correlation for seven displaced ganglion cells. The diameter of the thin segment was below reliable estimation by light microscopy. 3. We studied the possible significance of the thin axonal segment for ganglion cell impulse generation through a combination of electrophysiological recordings (intracellular and whole-cell recordings) together with computer modeling experiments. 4. Electrophysiological experiments are consistent with the idea that the thin segment and cell soma are less excitable than the initial segment region, which appears to be the principal site of initiation of the nerve impulse. The initial segment is that portion of the axon that is bounded by the soma (or proximal dendrite) at its origin and the thin segment at its distal end. 5. Computer simulations of impulse activation were carried out with the use of two different anatomic constraints: one class of simulations did not take into account the thin segment and assumed uniform cylinder conditions, whereas the other class of simulations included a model of the thin axonal segment. These comparative simulations indicate that the thin segment must contain a relatively high density of voltage-gated Na+ channels and support impulse traffic to account for physiological observations on orthodromic and antidromic impulse propagation. In addition, to match the physiological recordings, it is necessary for both the initial segment and the soma compartments to contain moderately high levels of Na+ channels. 6. Our physiological and simulation studies are consistent with the idea that the nerve impulse is normally initiated in the initial segment of axon and then spreads to activate a somatic impulse in the retrograde direction and the axonal impulse in the anterograde direction.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Site of action potential initiation in amphibian retinal ganglion cells. 156 62


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