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Query: UMLS:C0086543 (cataract)
 29,165 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Vitreous replacement with air, pure octafluorocyclobutane (C4F8), and mixtures of 40% C4F8 and 60% air was done in owl monkeys to determine ocular toxicity and duration of gas within the vitreous compartment. Large volumes of gas mixture and pure C4F8 caused posterior subcapsular cataract formation. Pure C4F8 expands in the vitreous within 24 to 48 hours. A 1.0-ml mixture of 40% C4F8 and 60% air lasted 12.7 days and did not cause ocular changes. However, anterior chamber aqueous replacement with pure C4F8 or gas mixture resulted in cataract production. Twenty-four and fourty-eight hours after injection of 0.1-ml pure C4F8 in the vitreous of experimental rabbits, presence of oxygen, nitrogen, and carbon dioxide was shown by gas chromatographic analysis. This finding supports the hypothesis of volume expansion secondary to diffusion of above-mentioned gases inside the C4F8 gas bubble.
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PMID:Octafluorocyclobutane in vitreous and aqueous humor replacement. 80 78

We studied freezing rates, cryoprotectants, and storage times on keratocyte viability, using rabbit corneal buttons incubated in either KM-26, CPTES, K-Sol, or TC 199 for 30 minutes at 4 degrees C. Using a controlled freezing rate (2 degrees/min to -40 degrees C), viabilities were 69 +/- 7% for KM-26, 113 +/- 21% for CPTES, 0.1 +/- 0.08% for K-Sol, and 0 +/- 0% for TC 199. The KM-26 and CPTES were further studied in corneas stored one to 30 days at -80 or -196 degrees C; CPTES had a better cryoprotective efficacy over one, three, and seven days of -80 degrees storage, and at liquid nitrogen storage temperature (-196 degrees) over one, 14, and 30 days storage. The findings demonstrate the superiority of CPTES. It provides better viability than KM-26 under similar conditions, and may enable long-term frozen storage of lenticules for later use in cryorefractive surgeries, with minimal loss of keratocyte viability.
J Cataract Refract Surg 1990 Nov
PMID:Long-term storage of frozen lenticules for cryorefractive surgery. 212 63

A 7-year-old girl was found to have a progressive axial crystalline cataract located in the embryonal, fetal, and infantile nucleus. She also had the unknown association of crystalline cataract with uncombable hair. Samples of the aspirate after extracapsular cataract extraction (ECCE) showed elongated, trigonal crystals on scanning electron microscopy. On transmission electron microscopy, the crystals were surrounded by a membrane sometimes consisting of up to 30 concentric layers. The crystals were found to contain carbon, oxygen, nitrogen, sulfur, and disulfide bonds. The findings suggest that a major constituent of the crystals was a sulfur-containing aminoacid, probably cystine. Protein analysis of the remaining lens material showed elevated alpha-, beta 2-, and gamma 2- crystallin levels. Analysis of the hair root status showed hair loss in the resting phase of the hair cycle with abnormal sheathing in most hairs that were in the growth phase.
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PMID:Crystalline cataract and uncombable hair. Ultrastructural and biochemical findings. 223 51

Exposure to ultraviolet (UV) lasers may result in pathology to either the cornea, lens or retina of the primate eye. The particular combination of exposure parameters (wavelength, peak power, pulsewidth, pulse repetition rate, and total energy delivered) determines the primary target tissue(s) in each instance. The effect may be acute or chronic, and the implicated damage mechanism may be categorized as photochemical, photoablative or thermal. This paper summarizes a number of specific cases where UV laser radiation affected one or more of the ocular tissues, describes the nature of the pathologies, and indicates what is known about the damage mechanism in each case. Ranges of exposure parameters where each ocular tissue is the most sensitive are defined. The cornea is most sensitive via a photochemical damge mechanism in the 260- to 280-nm range, where the threshold dose is approximately 5 mJ cm-2. For near-UV wavelengths (320-400 nm), different target molecules absorb the radiation and are susceptible to less efficient photochemical damage mechanism yielding corneal thresholds in the range of 10-100 J cm-2. However, we report acute cataract induction following exposure to a 337-nm nitrogen laser at 1 J cm-2 when the energy is delivered in a 10-ns pulse. Further, with longer pulsewidths (approximately 1 s) of comparable wavelength, retinal lesions were induced when 0.28 J was delivered to the eye. The data suggest that the acute lens effect is the result of a thermal mechanism, whereas the UV-induced retinal lesions result from a photochemical insult to the photoreceptors. Data presented include the action spectra for far- and near-UV-induced ocular damage, the pulsewidth and total energy dependencies of ocular thresholds, cumulative effects of repeated exposures, and repair or recovery rates.
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PMID:Ultraviolet-induced photochemical damage in ocular tissues. 265 62

1. The histidine requirement of growing kittens was determined from an experiment in which forty-eight kittens were randomly allocated to six amino acid-based diets supplying: 1.0, 1.5, 2.0, 2.5, 3.0 or 4.5 g histidine base/kg diet. 2. By 48 d it was obvious that 1.0 and 1.5 g histidine/kg diet were grossly inadequate so the kittens receiving these two diets were removed from the experiment. The other four groups of kittens continued to receive their diets for a total of 128 d. 3. Mean daily weight gain, nitrogen retention and food intake attained plateau values at 2.1 g histidine/kg diet. 4. Blood samples taken at 25 and 48 d after kittens were given the diets showed a significant effect of dietary histidine on haemoglobin (Hb) concentration. Hb and packed cell volume (PCV) attained asymptotic values at 3.0 g histidine/kg diet at 48 d. At 128 d, kittens consuming diets containing 2.0-4.5 g histidine/kg had similar Hb and PCV values. 5. Cataracts of both eyes were observed in two of nine female kittens which had received diets containing either 2.0 or 2.5 g histidine/kg. 6. A concentration of 3 g histidine/kg diet is recommended as a practical guide for feeding kittens. 7. There was a rectilinear relation (r2 0.99) between the logarithm of the histidine concentration of plasma and the concentration of histidine in the diet over the range 1.5-3.0 g histidine/kg diet.
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PMID:Histidine requirement of kittens for growth, haematopoiesis and prevention of cataracts. 368 51

Secondary ion mass spectrometry (SIMS) is a surface analytical technique with high sensitivity for elemental detection and microlocalization capabilities within the micrometre range. Quantitative analysis of epoxy resins and gelatin have been reported (Burns-Bellhorn & File, 1979). We report here the first application of this technique to quantitative microlocalization in the context of a physiological problem--analyses of sodium, potassium and calcium in normal and galactose-induced cataract in rat lens. It is known that during the development of galactose-induced cataract the whole lens content of potassium is decreased, sodium is increased and, in late stages, calcium concentration increases. Whether these alterations in diffusible ions occur homogeneously or heterogeneously is not known. Standard curves were generated from epoxy resins containing known concentrations of sodium, potassium or calcium organometallic compounds using the Cameca IMS 300 Secondary Ion Mass Spectrometer. Normal and cataractous lenses were prepared by freezing in isopentane in a liquid nitrogen bath followed by freeze-drying at -30 degrees C. After dry embedding in epoxy resin, 10 microns thick sections of lens were pressure mounted on silicon wafers, overcoated with gold, and ion emission measured under the same instrumental conditions used to obtain the standard curves. Quantitative analysis of an area 27 microns in diameter, or a total analysed volume of 1.1 microns3, was performed by using a mechanical aperture in the ion optical system. Ion images provided qualitative microanalysis with a lateral resolution of 1 micron. Control rat lenses gave values for sodium and potassium content with a precision of +/- 17% or less. These values were compared to flame photometry and atomic absorption measurements of normal lenses and were accurate within 25%. Analysis of serum and blood also gave accurate and precise measurements of these elements. Normal rat lenses had a gradient of sodium, and, to a lesser degree, of potassium from the cortex to the nucleus. Development of galactose-induced cataract was heterogeneous by morphological criteria, beginning at the lens equator and spreading from the cortex into the nucleus. However, the loss of potassium and increase in sodium concentration occurred at early stages in both the cortex and nucleus cells, possibly because these cells are interconnected by gap junctions. There is a local alteration in elemental content prior to morphologically demonstrable cataract formation.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Quantitative microlocalization of diffusible ions in normal and galactose cataractous rat lens by secondary ion mass spectrometry. 382 Feb 81

Previous studies have shown that cell uncoupling is paralleled by an increase in tightness and crystallinity of gap junction particle arrays. Gap junction crystallinity is believed to be part of the uncoupling mechanism because it can be produced in gap junctions isolated from lens fibers on direct exposure to uncoupling agents such as divalent cations or hydrogen ions. Some doubts, however, have been raised on the capacity of lens fiber junctions to crystallize and uncouple in situ. The present study shows that the gap junctions of rat lens fibers indeed crystallize after a treatment that increases drastically the membrane permeability to ions. The treatment consists of a brief immersion of the lenses in liquid nitrogen, followed by incubation for several hours in Tyrode's solution at 37 degrees C. Immediately after liquid nitrogen treatment, the lenses start gaining sodium and calcium while losing potassium, and eventually become opaque. Addition of 10 mM EDTA to calcium and magnesium-free Tyrode's solutions inhibits particle crystallization and lens cataract, whereas low concentrations of EDTA (1 mM) are not effective. These findings, together with preliminary data on the capacity of lens fibers to heal over, indicate that the gap junctions of lens fibers are capable of crystallizing and uncoupling in situ.
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PMID:Gap junction crystallization in lens fibers after an increase in cell calcium. 678 27

An 81-year-old man with a history of chronic pulmonary disease due to heavy smoking and ischemic heart disease had been suffering for the past few years from chronic constipation and urinary incontinence and was receiving medication for cardiopulmonary symptoms and urinary incontinence. He was admitted for repeated falling for a few months prior to admission. When put in the supine position, his blood pressure fell. He had bilateral pulmonary rales, consistent with lung disease, eccentricity of the left pupil (after cataract surgery), constriction of the right pupil, and absence of the pupillary light reflex. There was generalized hyperreflexia and a bilateral Babinski sign. He had normocytic, normochromic anemia; B12, folic acid and ferritin were within normal ranges, ESR was rapid, there was hyperglobulinemia (IgA and IgG), urea nitrogen and creatinine were increased but returned to normal after rehydration. ECG and chest X-ray were consistent with his cardiopulmonary status. Bone-marrow biopsy showed hypocellularity. IVP and barium enema were normal. Echocardiography revealed a possible old posterior wall myocardial infarction. CT-scan showed moderate cerebral and cerebellar atrophy, calcifications in the carotid and vertebral arteries, and small infarcts in both hemispheres. At this point, after an extensive survey of the literature, the diagnosis of Shy-Drager syndrome was proposed and proved by monitoring ECG and serum levels of noradrenaline during postural changes. He was treated with Fluorinef and there were no more episodes of postural hypotension. Several weeks after discharge he reported that he was feeling well and had not fallen since discharge.
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PMID:[Shy-Drager syndrome]. 775 2

The author assessed the physiological aging parameters of 38 apparently healthy subjects who were over 80 years old 1989, who were not on medication, and who had consulted with the Keio Health Counseling Center over 10 years. All subjects had no history of overt vascular disease and/or malignancy in 1989. In 17 of 38 subjects, physical, hematological and blood chemical parameters when they were in their 70s were analyzed. Many parameters were unchanged and remained within normal limits for ordinary adults. Cataract, atherosclerotic change of optic fundi and diagonal ear lobe creases were seen in all subjects during the study period. Concerning standard deviations, those of forced expiratory volume in one second/predicted vital capacity and pure tone average (acoustic ability) decreased with age, unlike those of other parameters. Furthermore, multiple regression analysis, revealed that serum albumin decreased but pure tone average, Scheie's atherosclerotic score, senile cataract, HDL-cholesterol blood urea nitrogen and forced expiratory volume in one second/predicted vital capacity increased with age. This study was not cohort study with selected subjects but shows very slight change of almost any parameter irrespective of age and abnormality can suggest the existence of disease.
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PMID:[The changes in physico-chemical parameters obtained from apparently healthy aged people followed over ten years]. 823 Jul 84

The physiological concentration of hydrogen peroxide in the aqueous humor was reported to range between 25 and 60 microM, and conditions leading to elevated levels could have important damaging effects such as cataract formation. However, the high concentration of ascorbic acid in aqueous humor, which is 20 times that of plasma, was recently shown to interfere in the dichlorophenol-indophenol assay for hydrogen peroxide. The actual concentration of hydrogen peroxide in this fluid has become a controversial issue. In the present study, we used the method of ferrous oxidation of xylenol orange (FOX1 assay) performed in a nitrogen atmosphere to accurately measure low levels of hydrogen peroxide, even in the presence of ascorbic acid at concentrations normally found in aqueous humor. Contrary to values reported in the literature, we observed that the concentration of hydrogen peroxide in the rabbit aqueous humor is less than 5 microM, which is the detection limit of the method.
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PMID:Measurement of hydrogen peroxide in biological samples containing high levels of ascorbic acid. 975 Jan 36


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