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Biomedical subjects

E Assia

Publications and source records attributed to E Assia.

At least 19 recordsLinked to original sources

Prognostic factors for visual acuity improvement after intravitreal triamcinolone injection.

PURPOSE: In some patients with macular oedema, intravitreal triamcinolone acetonide injection (IVTA) fails to improve visual acuity, although oedema shows clinical and angiographic improvement. Side effects can include increased intraocular pressure, cataract development, and (rarely) endophthalmitis. Our purpose was to identify prognostic factors for visual acuity improvement after IVTA. METHODS: Data on patients treated by IVTA for macular oedema were retrospectively reviewed. Three months postinjection, visual acuity was rated as 'improved' (two or more Snellen lines gained) or 'nonimproved' (unchanged or worsened). Comparative demographic data and pre- and post-IVTA clinical and fluorescein angiographic findings were analysed with SPSS software. RESULTS: Of 57 eyes (57 patients), 27 (47%) improved after IVTA. Initial visual acuity ('good', 'moderate', or 'poor') and aetiology of macular oedema (diabetic, venous occlusion, or pseudophakic) did not differ between the two groups. Improvement occurred in significantly more eyes with clinical or angiographic evidence of cystoid macular oedema (CME) than in those with diffuse retinal thickening (P=0.04) or diffuse leakage on fluorescein angiography (P=0.02), respectively, and in significantly more pseudophakic than phakic eyes (P=0.046). CONCLUSIONS: Pseudophakia and clinical or angiographic CME, but not aetiology or initial visual acuity, were prognostic of visual acuity improvement after IVTA for macular oedema.

Adult↗

Cataract surgery performed with continuous positive airway pressure (CPAP) ventilation.

PURPOSE: To report a case in which cataract surgery was performed under local anesthesia, with continuous positive airway pressure-assisted ventilation. METHODS: A 40-year-old woman with myotonic dystrophy and severe orthopnea, who could not lie supine because of severe orthopnea, and who was a high-risk candidate for general anesthesia, underwent cataract surgery with continuous positive airway pressure ventilation by face mask. RESULTS: The patient underwent uneventful phacoemulsification and intraocular lens implantation in her left eye, while under continuous positive airway pressure ventilation. CONCLUSION: Selected patients who are unable to lie supine for ocular surgery because of severe orthopnea, and who are at risk for systemic complications under general anesthesia, may be evaluated for continuous positive airway pressure-assisted surgery.

Adult↗

Overcoming the language barrier in visual field testing.

PURPOSE: To evaluate the effect of using recorded instructions in patients' native language compared with interpreter-assisted instructions on the reliability and duration of the visual field test. PATIENTS AND METHODS: Sixty patients referred for visual field testing were included in the study. Thirty-five had limited or no knowledge of the Hebrew language, and 25 control patients were fluent in Hebrew, the native language. None had previous experience with automated perimetry. Patients were randomized to receive recorded instructions on the visual field test in their native language or translator-assisted instructions by the technician before performing the test. For each patient, the time required for instructions and test performance and the reliability indices were documented. RESULTS: The method of instruction (recorded or interpreter-assisted) did not affect the time required for patient instructions (66 +/- 24 seconds and 57 +/- 30 seconds, respectively), the time for test performance (7.2 +/- 1.5 minutes and 7.8 +/- 1.8 minutes, respectively), and test reliability as measured by the rate of fixation losses. Regardless of the method of explanation, the time required for instructions and for performing the test were significantly shorter for Hebrew speakers than for non-Hebrew speakers. CONCLUSION: The use of a recorded explanation in the patient's native language before visual field testing is an applicable method for patient instruction. Clinics in areas with multilingual populations may use this method to save technicians time, without adversely affecting the time required for performing the test and its reliability.

Aged↗

Charles Bonnet syndrome in glaucoma patients with low vision.

PURPOSE: To characterize the nature and frequency of Charles Bonnet syndrome in glaucoma patients with low vision. PATIENTS AND METHODS: All patients attending the glaucoma clinic during a period of 10 months who had visual acuity of 20/80 or less in both eyes were included in this study. Each patient was questioned about the occurrence of visual hallucinations. Those who responded positively had a thorough interview relating to the characteristics of the hallucinations. Medical history and social history were taken, followed by a complete ocular examination. RESULTS: Eighty-nine patients met the inclusion criteria. Eleven patients (12.3%), eight men and three women, admitted to having experienced visual hallucinations. Except for one case, the patients did not disclose this experience previously. Eight patients had one repeatable hallucination, and three patients experienced more than one sight. The visions were usually sharp, and the figures were occasionally incomplete. Most hallucinations were chromatic. Frequency of hallucinations varied between daily and weekly, and duration was mostly a few minutes. In addition to glaucoma, nine of the eleven patients had other ocular findings that could have contributed to the reduction of vision. CONCLUSION: Visual hallucinations are not rare in glaucoma patients with low vision. Patients tend to conceal their experience of visual hallucinations, but a discussion of these phenomena with the patient and assurance of their harmless nature will reduce his or her anxiety and concerns.

Aged↗

Dose and temporal parameters in delaying injured optic nerve degeneration by low-energy laser irradiation.

Low-energy laser irradiation has been reported to postpone the degenerative processes in crushed optic nerves of rats, which are part of the nonregenerable mammalian central nervous system. In the present study, we evaluated the optimal irradiation parameters for this purpose. Optic nerves of 141 rats were subjected to crush injury and then irradiated through the eye, starting at different points of time before or after the injury, for different durations and periods, using various intensities of either helium-neon laser or noncoherent infrared light (904 nm). The effect was evaluated by measurements of the compound action potentials of the nerve segments between the site of injury and the optic chiasm. The compound action potential amplitude of the crushed nonirradiated nerves, as measured 2 weeks after the injury, was found to be 0.51 +/- 0.30 mV, in contrast to 3.10 +/- 1.03 mV measured in 232 normal nerves. Irradiation with a 10.5 mW helium-neon laser for 2 and 3 min once a day for 14 consecutive days resulted in maximal preservation of action potentials (1.78 +/- 0.72 and 1.95 +/- 0.71 mV, respectively). Irradiations beginning immediately prior to the injury were as effective as irradiations beginning soon after it. Irradiations for longer than 3 min or twice a day aggravated the damage. Noncoherent infrared light was ineffective or adversely affected the injured nerves. Our experiments suggest that optimal delay of posttraumatic optic nerve degeneration in rats is attainable with 10.5 mW helium-neon laser irradiations for 2 or 3 min once a day for 14 consecutive days.

Action Potentials↗

Small-incision manual extracapsular cataract extraction using selective hydrodissection.

Hydrodissection is a technique in which balanced salt solution is injected through a cannula into various layers of a cataractous lens to separate the lens lamella in a nonspecific location. Selective hydrodissection allows separation of the lens lamella at different desired anatomical layers. The technique allows the smallest possible nucleus, ie, the hard-core nucleus, to be hydroexpressed as a separate entity, requiring, correspondingly, a relatively small capsulorhexis and limbal incision. Then, in a second maneuver, the epinucleus, which engulfs the hardcore nucleus to form the adult nucleus, also can be aspirated or hydroexpressed as a whole. Selective hydrodissection permits scleral incision and stitchless surgery in planned extracapsular cataract extraction and also may serve as an intermediate step for surgeons who wish to convert to or learn phacoemulsification techniques.

Cataract Extraction↗

Lens anatomical principles and their technical implications in cataract surgery. Part I: The lens capsule.

Optimal fixation and position of an intraocular lens (IOL) is achieved when it is located in the capsular bag. A peripheral tear from the central opening to the lens periphery is associated with a high incidence of dislocation of at least one loop from within the capsular bag and lens decentration. A central round continuous capsulectomy (capsulorhexis), within the zonule-free area, provides long-term and balanced IOL fixation. To perform a well-controlled capsulectomy, a deep and stable anterior chamber should be maintained throughout the surgery. This is achieved by using a continuous anterior chamber maintainer that regulates the pressure in the anterior chamber. This paper reviews the clinical anatomical guidelines of the lens capsule and the anterior chamber and presents the authors' preferred technique for optimal anterior capsulectomy.

Anterior Chamber↗

Lens anatomical principles and their technical implications in cataract surgery. Part II: The lens nucleus.

Preservation of the intact ("true") capsular bag, with no tears to the periphery, is essential to assure permanent in-the-bag fixation of the intraocular lens. Removal of a large nucleus using the open-system planned extracapsular cataract extraction (ECCE) technique is often associated with tearing of the capsulectomy or serious complications such as zonular rupture, vitreous loss, unintended intracapsular cataract extraction, or posterior lens prolapse. A closed-system planned ECCE technique which allows a safe removal of the lens while maintaining the integrity of the capsular bag is presented. Hydrodissection of the lens nucleus to an epinucleus and a central hard nucleus allows hydroextraction of the small hard core while pushing the posterior capsule backward. The positive pressure in the anterior chamber, provided by the anterior chamber maintainer, keeps the position of the lens steady in its natural location, and minimizes the stress on the zonular apparatus during nucleus delivery. The remaining epinucleus can be either hydroexpressed or aspirated. Fracturing the central core, when possible, enables removal of the lens material through a small limbal incision. Viscoelastic material can be combined with a low-flow, anterior chamber maintainer in a closed-system and provides a useful surgical tool.

Cataract Extraction↗

Hyponatremia induced by exercise: a 24-hour endurance march study.

In our previous studies on the relationship between prolonged physical stress and muscle enzyme activities, a number of individuals suffered a hyponatremic state. The present study was conducted to evaluate the effect of prolonged physical stress on the development of hyponatremia. Seventeen physically fit male subjects were studied during a 24-hour endurance march. Serum sodium, that averaged 142 +/- 2 before the march, decreased during the march to 135 +/- 2 mEq/l (p less than 0.01 versus before the march). Blood and plasma volumes increased by 8 and 16% (p less than 0.05), respectively. Creatinine clearance before the march declined from 118 +/- 24 to 74 +/- 19 ml/min (p less than 0.005) during the march and correlated negatively with serum sodium (p less than 0.002; r = 0.59). Urinary sodium excretion before the march was 132 +/- 55 and during the march was 123 +/- 62 mEq/24 h. Free water clearance rose during the march and correlated negatively with serum sodium (p less than 0.001), suggesting an appropriate renal diluting response. However, the fall in serum sodium correlated positively with water intake (p less than 0.01; r = 0.59). These results show that hyponatremia develops during endurance marching in normal subjects on an unrestricted high water intake. The renal response to water intake is appropriate; however, the subjects fall to produce maximally diluted urine. Therefore, we suggest that water intake should follow physiological needs and not forced to cause hyponatremia during prolonged physical stress.

Adult↗

Transscleral cyclophotocoagulation using a semiconductor diode laser in cadaver eyes.

We studied the effectiveness of semiconductor diode laser transscleral cyclophotocoagulation in cadaver eyes using the Miyake technique and light microscopy. Thermal lesions in the ciliary processes were induced with 0.7-second, 1200-mW, and 100- to 500-microns applications, 0.5 mm from the surgical limbus and defocused 1 mm posteriorly. An effective ciliary body reaction was observed grossly as tissue blanching, shrinkage, and pigment dispersion; and histologically, as coagulation necrosis and epithelial cell disruption. No damage to crystalline or intraocular lenses was evident. This successful application of diode laser transscleral cyclophotocoagulation in cadaver eyes suggests that it may prove useful in treating patients with glaucoma.

Ciliary Body↗

[Physiological responses to heat and effort and complaints of hyperperspiration].

The sensation of hyperperspiration is a common complaint in hot, humid climates. 54 men and 20 women, 18-47 years old, who had this complaint and 27 male control subjects were examined at rest and after 1 hour of mild exercise (40W) under conditions of heat stress (37 degrees C, 50% relative humidity). During exposure to heat rectal and skin temperatures and heart rate were measured every 15 min. Sweat rate was calculated for the entire period of exposure and sweat gland density was measured at 0, 60 and 120 min. Only insignificant deviations from baseline values were noted at rest. During exercise the sweat rate of the men with the complaint was within normal limits and similar to that of the control men (285 +/- 75 ml/m2 vs 272 +/- 48). Matching for age and V02 max revealed no significant differences in physiological responses of men with and those without the complaint. Women with the complaint lost 25-30% less fluid (226 +/- 67 ml/m2) and their concentrations of active sweat glands were lower than in either of the male groups. 2 men and 1 woman with the complaint and 1 control lost 400-425 ml/m2 during exercise, the upper limit of normal. Only 1 subject showed hyperperspiration (855 ml/m2) during the test. All physiological parameters examined in these 5 subjects were within normal limits. It is concluded that the complaint of hyperperspiration in our self-selected group is basically a subjective feeling and has no pathological basis. None of the subjects was heat intolerant.

Adult↗

Temporal parameters of low energy laser irradiation for optimal delay of post-traumatic degeneration of rat optic nerve.

Compression injury of a central nerve results in its degeneration with irreversible loss of function due to the inability of the mammalian central nervous system (CNS) to regenerate. In contrast, the CNS of lower vertebrates has a high capacity to regenerate. Recently, low energy laser irradiation was shown to attenuate degeneration in injured CNS nerves. The optic nerves of rats were subjected to moderate crush, calibrated so that some electrophysiological activity was preserved. The nerves were then subjected to low energy laser irradiation (10.5 mW, 2 min daily) for various periods. The electrical activity of the nerves, distal to the site of injury, was determined by measuring the compound action potential at the termination of the experiment. Two weeks of irradiation begun immediately after injury and continued daily thereafter, resulted in a compound action potential which was significantly higher (mean +/- S.E.M. 1856 +/- 535 microV) than that of non-irradiated injured nerves (351 +/- 120 microV). The effect was temporary and subsided within a week. This two-week irradiation was slightly more effective than a treatment lasting one week (1406 +/- 225 microV) and was significantly more effective than 4 days of irradiation (960 +/- 133 microV). The number of treatments is therefore important. The time at which the treatment commences relative to the injury is also critical. Irradiation initiated two hours after the crush was about half as effective as immediate irradiation (810 +/- 42 microV). No apparent effect was evident when the laser was applied for the first time 5 h, or longer, after the crush.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Plasma-cortisol levels in experimental heatstroke in dogs.

The effect of external heat-load, exercise and dehydration on dynamic changes in plasma cortisol during the development of heatstroke was investigated. Thirty-three unanesthetized dogs were tested under two sets of climatic conditions: comfort conditions and hot-dry climatic conditions, half of them while exercising. Half of the dogs in each group were rehydrated. None of the dogs that were investigated at room temperature suffered heatstroke. Of the dogs exposed to high ambient temperature, all of the exercising, as well as five out of six non-hydrated dogs and one rehydrated non-exercising dog suffered heatstroke. Significant dehydration (6%-7% of body weight), occurred only under high ambient temperature. Plasma cortisol levels of all dogs that suffered heatstroke rose conspicuously for at least 5 h and returned to normal levels 24 h later. Cortisol levels of dogs who did not experience heatstroke remained within the normal range. Cortisol levels correlated with the severity of the stress leading to heatstroke. High and rising levels of cortisol, several hours after body temperature returns to normal, may support the diagnosis of heatstroke.

Animals↗

Prediction of physical performance through muscle enzymes activity.

Physical performance deteriorates during strenuous exercise as manifested by a decrease in maximal aerobic power and increased activity of serum muscle enzymes. The relationship between these parameters was investigated in 41 trained subjects during 24 h marches and the following recovery period. Peak O2 uptake and serum activity of creatine phosphokinase (CPK) and glutamic oxalacetic transaminase (GOT) were measured. During the marches there was a simultaneous, significant elevation in serum CPK and GOT activity and a significant reduction in peak O2 uptake. During the early recovery period (24 h) no significant changes occurred in muscle enzyme activity and peak O2 uptake; thereafter (up to 72 h after the end of the march), a gradual decline in enzyme activity levels with a concomitant increase in peak O2 uptake was observed, reaching pre-march values. A "mirror image" relationship between muscle enzyme activity and peak O2 uptake was found during three clearly distinguished phases: a) 24 h march, b) early recovery stage and c) late recovery stage. These findings suggest that muscle enzyme leakage from muscle cells is closely related to the decline in muscular function and aerobic power. Thus, muscle enzyme activity might be a practical measure of physical performance capacity during the early and late stages of recovery from prolonged endurance exercise.

Adult↗

Relationship between morphology and functional ability of regenerated corneal endothelium.

Cat corneal endothelium was damaged by a methylmethacrylate segment introduced into the anterior chamber. Within 3 to 6 months after each such operation the endothelial cell density (ECD) diminished, ranging from 1933 to as low as 450 (78% to 16%, respectively, of its preoperative value [PV]). Decrease in the ECD to between 1050 and 1150 (40%-45% of PV) made no impact on the corneal thickness (group 1: "non-swollen" corneas); further decrease was followed by an increase of the corneal thickness to a level of 11.5%-73.5% more than its preoperative value (group 2: "swollen" corneas). The coefficient of variation of ECD increased in both groups. The number of hexagonal endothelial cells diminished, while cells with three or nine or more facets appeared. All these changes were much more pronounced and verifiable in the group 2 corneas, which were distinguished by the appearance of giant endothelial cells, 2957-4095 micron2, ie, 7.5-13.5 times larger than the cells of undamaged endothelium. These data appear to indicate that the decrease of ECD to 1050 to 1150 (40% to 45% of its PV) does not provoke decompensation of the dehydrative function of the endothelium, whereas further decrease does provoke such decompensation, the giant endothelial cells probably being the main factor in this phenomenon.

Animals↗

Regeneration of cat corneal endothelium induced in vivo by fibroblast growth factor.

The corneal endothelium of man, primates and carnivores has limited regenerative ability. Fibroblast growth factor (FGF) stimulates the proliferation of various mesoderm-derived cells, including corneal endothelial cells, in vitro. In the present work the effect of FGF on the regeneration of injured cat endothelium in vivo was studied. Scraping of cat corneal endothelium off Descemet's membrane was carried out by a specially designed instrument. FGF from crude preparations (25 micrograms in 50 microliter saline) or affinity purified FGF (0.5 micrograms in 25 microliter saline) were injected immediately after the scraping of the endothelium, and in both cases significant stimulation of endothelium regeneration was observed. During the first 2 weeks after scraping, the endothelial cell density (ECD) in FGF-treated eyes was higher by a factor of 1.7-2.3 than that in the control eyes. This marked difference decreased with time, but even after 12 weeks the ECD in FGF-treated eyes was higher by a factor of 1.15-1.30 than in the control eyes. Furthermore, FGF improved the polygonal shape of the cells and decreased the corneal thickness. These results clearly demonstrate the efficacy of FGF in inducing the proliferation of cat corneal endothelial cells in vivo and indicate its potential application in clinical practice.

Animals↗

Changes of white blood cell count during prolonged exercise.

Leukocytosis was postulated to accompany short- and medium-length exercise; in this report, we have studied the changes in leukocyte count during and following prolonged exercise. White blood cell (WBC) counts were obtained in 15 endurance-trained subjects before, during, and at a recovery period after an ultralong exercise (120 km march), lasting 24 h. WBC counts increased after 16 h march from a baseline value of 8.5 +/- 0.3 10(9) l-1 to 11.3 +/- 0.8 10(9) l-1 (P less than 0.05) and then declined to 7.1 +/- 0.9 10(9) l-1 after 24 h march with no further significant changes during 64 h of recovery. These observations were supported by previous findings in three separate marches performed by a second group (40, 70, and 120 km). A parallel increase in plasma creatine phosphokinase activity from 127 +/- 4.4 ul-1 to 539 +/- 106.3 ul-1 was observed after 16 h march (P less than 0.01), indicating muscle cell damage. Our findings suggest that in extremely long marches, WBC counts return to baseline values before exercise is terminated. This phenomenon may reflect WBC infiltration to damaged muscle tissue.

Adult↗