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Biomedical subjects

R Ofri

Publications and source records attributed to R Ofri.

18 recordsLinked to original sources
PubMed2004

The development of the refractive state in the newborn Thomson gazelle.

Changes in refractive error during the first 3 months of life were studied retinoscopically in six Thomson gazelles ( Gazella thomsoni). Animals were hand-raised to allow repeat testing over time without chemical restraint. Refraction results were correlated with ultrasound measurements of intraocular dimensions, and with values in adult gazelles. Gazelles are born hyperopic with a mean refractive error of 3.44+/-0.31 D. By day 50, the animals are virtually emmetropic (0.13+/-0.21 D) and remain so in adulthood (0.03+/-0.09 D). The refractive error is highly correlated with the axial length ( r(2)=0.96) and with the vitreous chamber depth ( r(2)=0.83), but not with anterior chamber depth. Significant with-the-rule astigmatism was recorded ( P<0.001).

Aging↗
PubMed2002

Intraocular pressure and tear production in five herbivorous wildlife species.

The intraocular pressure and rate of tear production were measured in 18 addax antelopes (Addax nasomaculatus), four impalas (Aepyceros melampus), 11 wide-lipped rhinoceroses (Ceratotherium simum), 10 white-tailed wildebeests (Connochaetes gnou) and seven scimitar-horned oryxes (Oryx dammah). The animals were anaesthetised with an intramuscular injection of etorphine hydrochloride and acepromazine maleate, and the Schirmer tear test I was used to evaluate tear production, and applanation tonometry was used to evaluate the intraocular pressure. The mean (sd) rate of tear production ranged from 17.6 (3.1) mm/minute in the rhinoceros to 28.8 (8.3) mm/minute in the addax. The intraocular pressure ranged from 8.0 (1.2) mmHg in the impala to 32.1 (10.4) mmHg in the rhinoceros. The rate of tear production in the addax and the intraocular pressure in the rhinoceros appear to be the highest values of these variables to have been reported in any species.

Animals↗
PubMed2002

Effects of propofol as an anaesthetic agent in adult lions (Panthera leo): a comparison with two established protocols.

The aims of this study were to evaluate the effects of a ketamine/propofol anaesthetic protocol in lions (Panthera leo), and to compare it to two commonly used anaesthetic protocols. Seventeen adult lions were anaesthetised using three different protocols. Group XK (n=6) was anaesthetised with intramuscular (i.m.) injections of xylazine and ketamine. Group KD (n=5) was anaesthetised with an i.m. injection of ketamine, followed by an intravenous (i.v.) injection of ketamine and diazepam. Group KP (n=6) was anaesthetised with an i.m. injection of ketamine followed by an i.v. injection of propofol. There was a significant difference in heart rate (P<0.0002), which was lowest in group XK and highest in KD. Jaw tone was significantly lower in Group XK (P<0.05). No undesirable effects were noted following injection of the propofol. Propofol was a suitable and safe drug for maintenance of anaesthesia in adult lions.

Anesthesia↗
PubMed2001

Development of the refractive state in eyes of ostrich chicks (Struthio camelus).

OBJECTIVE: To follow the development of the refractive error in the eyes of ostrich chicks from age 0 to day 37 after hatching. ANIMALS: 35 ostrich chicks. PROCEDURES: Spot retinoscopy was conducted to assess refractive error in ostrich chicks. Seventy eyes of 35 ostrich chicks were examined. Of these, 18 chicks were followed over time. At least 4 serial measurements (at 2- to 7- day intervals) were conducted in each of these chicks from day 1 to 37 after hatching. Seventeen additional chicks were examined on days 0, 3, 12, and 19 after hatching. RESULTS: Ostrich chicks were myopic at hatching, with a mean +/- SD refractive error of -4.47 +/- 0.15 diopters (D). The refractive error rapidly decreased during the first week of life, and by day 7 after hatching, chicks were slightly hyperopic, with a mean refractive error of 0.42 +/- 0.12 D. After day 7, there were no significant differences in the mean refractive error. CONCLUSIONS: The development of optics in the ostrich eye appears to be unique among animals and is characterized by myopia at hatching, rapid onset of emmetropia, and minimal variation in refractive error among chicks.

Animals↗
PubMed2001

Intraocular pressure and tear production in captive eland and fallow deer.

Applanation tonometry was used to estimate intraocular pressure (IOP) and Schirmer tear test (STT) I was used to estimate tear production in both eyes of 12 juvenile elands (Taurotragus oryx) and one eye each of 15 Asian fallow deer (Dama mesopotamica). Mean (+/- standard deviation) IOP was 14.6 +/- 4.0 mm Hg in the eland and 11.9 +/- 3.3 mm Hg in the deer. Mean tear production was 18.7 +/- 5.9 mm/min in the eland and 10.5 +/- 6.5 mm/min in the deer. The large variation in IOP between two members of the family Bovidae, the elands reported here and the Thomson gazelle (Gazella thomsoni) for which we previously reported a mean pressure of 7.6 mm Hg, illustrates the need to establish reference values for each species. Tear production may be influenced by the species' natural habitat.

Animals↗
PubMed2000

How low can we get? Tonometry in the Thomson gazelle (Gazella thomsoni).

PURPOSE: To establish a normal reference range of intraocular pressure estimates in Thomson gazelles (Gazella thomsoni). MATERIALS AND METHODS: Applanation tonometry was conducted in 22 eyes of 11 gazelles anesthetized for transportation purposes with a mixture of etorphine hydrochloride and acepromazine maleate. Five sequential readings using a Tono-Pen XL (Mentor Ophthalmics, Inc., Norwell, MA) were obtained from each eye. Results were analyzed for the effect of age, weight, gender, side, and replicate readings and were compared with estimates in other species. RESULTS: Mean (+/- standard deviation) intraocular pressure estimate in 22 eyes of 11 gazelles was 7.6 +/- 1.6 mm Hg. None of the variables tested had a significant effect on the results. CONCLUSIONS: To date, the intraocular pressure estimates in the Thomson gazelle are the lowest reported in any species.

Animals↗
PubMed2000

The effect of 0.12% unoprostone isopropyl (rescula) on intraocular pressure in normotensive dogs.

Rescula (0.12% unoprostone isopropyl) is the first docosanoid compound approved for treatment of glaucoma in humans. It is commercially available in Japan, and is undergoing clinical testing elsewhere. The aim of this study was to evaluate the effect of Rescula on intraocular pressure (IOP) in normotensive dogs. After establishing a baseline diurnal IOP curve, six dogs were unilaterally treated with Rescula while the contralateral eye was treated with a placebo. Applanation tonometry was performed in both eyes, and pupil size was evaluated, 30 min after treatment, and at 1-hr intervals for the next 9 hr. Rescula caused a significant (p=0.014) and long-lasting decrease in IOP, from 20.49+/-2.02 mm Hg in control eyes to 15.49+/-0.69 mm Hg in treated eyes. These results suggest that Rescula is potentially efficacious in treatment of canine glaucoma.

Animals↗
PubMed1999

The effect of elevated progesterone levels on intraocular pressure in lions (Panthera leo).

Recently, we reported that intraocular pressure (IOP) in juvenile male lions (Panthera leo) is significantly higher than in juvenile lionesses. Whilst we could not ascertain the basis for this gender-related difference, we suspected that they were the result of fluctuations in levels of sex hormones. Because 19 of the 22 lions described in our previous report had to be re-anaesthetized, we repeated tonometry in these animals, to try and correlate between IOP and the levels of progesterone, oestrogen and/or testosterone. Based on elevated (>5 ng ml(-1)) levels of progesterone, lionesses were divided into a luteal (n = 8) and a non-luteal (n = 13) group. In the luteal group, mean IOP was 27.07+/-2.15 mm Hg, significantly (P = 0.001) higher than in the non-luteal group (21.61+/-2.70 mm Hg). Oestrogen, testosterone, anesthesia and age had no significant effect on IOP. It is suggested that elevated progesterone levels associated with the luteal phase in lionesses cause increased resistance to aqueous humor outflow, leading to IOP elevation. Similar ocular hypertension has been observed in rabbits following exogenous progesterone application, but this is the first report on the hypertensive effect of endogenous progesterone on IOP.

Animals↗
PubMed1999

Tear production in three captive wild herbivores in Israel.

The Schirmer tear test (STT) I was performed to evaluate tear production in 12 captive Nubian ibex (Capra ibex nubiana), 10 captive Burchell's zebras (Equus burchelli) and five Arabian oryx (Oryx leucoryx) at the Tel-Aviv Ramat-Gan Zoological Center (Israel). Mean (+/- standard deviation) STT values were 13.2 +/- 5.1 mm/min in the ibex, 23.4 +/- 3.4 mm/min in the zebra and 12.7 +/- 4.8 mm/min in the oryx. There were no significant effects of gender, age, weight, or side of the eye. There were no significant differences in STT values between ibex and oryx, but tear production in both species was significantly lower than in zebras. Knowledge of normal tear production values is important for the differential diagnosis of conjunctivitis and keratitis in these species.

Animals↗
PubMed1998

Acute blindness associated with monoclonal gammopathy induced by Ehrlichia canis infection.

Ehrlichia canis infection was diagnosed in a Labrador retriever presented with a primary complaint of acute blindness. Ocular signs on admission included bilateral hyphema, retinal haemorrhage and retinal detachment. Serum protein electrophoresis results revealed monoclonal gammopathy. This report discusses and suggests the pathogenesis of ocular bleeding in canine monocytic ehrlichiosis. Blood hyperviscosity, elevation in oncotic pressure, vasculitis, thrombocytopenia and platelet dysfunction are all proposed to be important factors in the pathogenesis of acute blindness in canine monocytic ehrlichiosis.

Acute Disease↗
PubMed1998

Arnold-Chiari malformation in a captive African lion cub.

Progressive ataxia, delayed growth, dementia and tremors were noted in a female African lion (Panthera leo) cub at the Tel-Aviv Ramat-Gan Zoological Center (Israel). The lioness was 3-mo-old when clinical signs were first noticed. Repeated neurological evaluations and blood tests were conducted in an attempt to establish a diagnosis. A congenital abnormality was suspected and the lioness died 6 molater. Post mortem examination revealed an Arnold-Chiari malformation. The abnormality was classified as a Chiari type 2 malformation, based on the herniation of the cerebellar vermis and paravermis and the slight caudal displacement of the medulla, combined with lack of displacement in other parts of the brainstem.

Animals↗
PubMed1998

The effects of anesthesia and gender on intraocular pressure in lions (Panthera leo).

Intraocular pressure (IOP) was measured in a pride of 22 (11 males, 11 females) lions (Panthera leo) using a Schiotz tonometer. Two anesthetic protocols were used in the study. Lions in group I (n = 14) were anesthetized using xylazine, atropine sulfate, and ketamine. Lions in group II (n = 8) were anesthetized using ketamine and diazepam. Five sequential readings were taken from each eye of every lion. There were no significant differences in IOP between the two anesthetic groups, between left and right eyes, or over the five readings. The IOP was significantly higher in males than in females, controlling for age and weight. The mean (+/-SD) tonometer reading in 22 eyes of 11 male lions was 2.9 (+/-0.5) mm; with a 95% confidence interval (CI) of 1.6-4.5 mm. The mean tonometer reading in 22 eyes of 11 female lions was 4.0 (+/-0.7) mm, with a 95% CI of 1.8-6.3 mm. Using the 1955 Friedenwald human calibration table, the estimated mean IOP in 22 eyes of 11 male lions was 24.9 (+/-2.0) mm Hg, with a 95% CI of 20.4-29.4 mm Hg. The estimated mean IOP in 22 eyes of 11 female lions was 20.9 (+/-2.4) mm Hg, with a 95% CI of 15.6-26.3 mm Hg.

Adjuvants, Anesthesia↗
PubMed1996

Haematological, ocular and skeletal abnormalities in a samoyed family.

Haematological, ocular and skeletal abnormalities were documented in a samoyed male and its five offspring. Haematological abnormalities, found in repeated tests in all the dogs, included marked eosinophilia, eosinophilic bands and absence of Barr bodies. Two of the dogs had bilateral buphthalmia, retinal detachments and other ocular abnormalities. Three of the dogs had skeletal abnormalities including chondrodysplasia (dwarfism) and brachygnathia (undershot jaw). A similar combination of inherited skeletal and ocular disorders, without the haematological abnormalities, has been described in samoyeds. Acquired causes for the haematological findings, which are similar to the inherited Pelger-Huët anomaly described in several species, have been eliminated. Eosinophilic bands and scarcity of Barr bodies could be a marker, or a previously unreported manifestation, of an inherited disorder in samoyeds.

Animals↗
PubMed1993

Primary open-angle glaucoma alters retinal recovery from a thiobarbiturate: spatial frequency dependence.

Electrophysiological responses of the retina to a series of grating stimuli (6-768 min of arc/phase) were recorded in seven sessions using normal Beagles and in 21 sessions using Beagles afflicted with inherited glaucoma. A 15 degrees and a 30 degrees field, centered around the animal's area centralis, were used to stimulate the central retina. Two recording series were completed on each animal, with both stimulus sizes presented in each recording session. The first recording took place 30 min, and the second 2 hr, after the injection of thiamylal sodium. The signals recorded from the toroidal 15 degrees of the retina of the glaucomatous dogs during the second recording were significantly larger than those of the first recording. This difference was found only for the larger (> 48 min of arc/phase) gratings. No significant differences were found between the first and second recordings from the central 15 degrees of glaucomatous dogs, nor at any site in the normal dogs.

Animals↗
PubMed1993

Chronic ocular hypertension alters local retinal responsiveness.

Electrophysiological responses of the retina and visual cortex to a series of grating stimuli (6-768 minutes of arc) were recorded in seven sessions using normal beagles, 21 sessions using beagles afflicted with inherited ocular hypertension, and 12 sessions using rhesus monkeys. A 15 degrees field centred around the animal's area centralis or fovea was used to stimulate the central retina. A 30 degrees field, centred on the same spot, was then used to stimulate the larger area. Two recording series were completed on each animal, with both field sizes presented in each recording session. The first recording took place 30 minutes after and the second 2 hours after the injection of thiamylal sodium. Only the signals from the toroidal 15 degrees of the retina of the hypertensive dogs were remarkably larger during the second recording (p = 0.001). No significant differences were found between the two recordings from the retinas of normal dogs or monkeys, nor were there any significant differences between the two recordings from above the cortex in any group. Several hypotheses are proposed to explain the basis for the interaction of thiamylal with the more peripheral retinal function in clinically glaucomatous dogs.

Animals↗
PubMedDate not supplied

Cataract development in diabetic sand rats treated with alpha-lipoic acid and its gamma-linolenic acid conjugate.

BACKGROUND: Diabetes commonly leads to long-term complications such as cataract. This study investigated the effects of alpha-lipoic acid (LPA) and its gamma-linolenic acid (GLA) conjugate on cataract development in diabetic sand rats. METHODS: Two separate experiments were conducted. In Experiment 1, sand rats were fed a "high-energy" diet (70% starch), an acute model of Type 2 diabetes, and injected with LPA. In Experiment 2, the animals received a "medium-energy" diet (59% starch), a chronic diabetic model, and were intubated with LPA or its GLA conjugate. Throughout the experiments, blood glucose levels and cataract development were measured. At the termination of the experiments, lens aldose reductase (AR) activity and lenticular reduced glutathione (GSH) levels were analyzed. RESULTS: LPA injection significantly inhibited cataract development and reduced blood glucose levels in rats fed the "high-energy" diet. Lens AR activity tended to be lower, while lenticular GSH levels increased. In sand rats fed a "medium-energy" diet (59% starch), LPA intubation had no effect on blood glucose levels and cataract development but GSH levels were increased. In contrast, sand rats intubated with GLA conjugate showed the highest blood glucose levels and accelerated cataract development. The conjugate treatment also decreased lenticular GSH content. CONCLUSIONS: The hypoglycemic effects of LPA are beneficial in the prevention of acute symptoms of Type 2 diabetes. It remains to be shown that the antioxidant activity of LPA is responsible for prevention or inhibition of cataract progression in sand rats.

Aldehyde Reductase↗