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Biomedical subjects

M Belkin

Publications and source records attributed to M Belkin.

At least 163 records · Page 9Linked to original sources
PubMed1984

Substances originating from the optic nerve of neonatal rabbit induce regeneration-associated response in the injured optic nerve of adult rabbit.

We have recently shown that cell bodies of an injured optic nerve of adult rabbit can be induced to express regeneration-associated response by external signals derived from nonneuronal cells of regenerating nerves of lower vertebrates. In this study it is shown that even substances derived from a nonregenerating mammalian system also can trigger such a regenerative response. Thus, substances derived from intact nerves of neonatal rabbits and of adult rabbits, to a lesser extent, were active in triggering a regeneration-associated response, whereas substances derived from injured nerves of adult rabbit were not. However, if subsequent to the injury the nerve was implanted with silicone tube containing medium conditioned by neonatal optic nerves, the substances derived from the implanted injured nerve were active. Thus, it appears that the ability of a periaxonal environment to provide triggering substances correlates with axonal growth. Therefore, we named these substances "growth-associated triggering factors" (GATFs). It is suggested that mammalian cells are unable to express a regenerative response after an injury due to the failure of their nonneuronal cells to produce regeneration-triggering substances. This disability may be circumvented by an appropriate implantation procedure.

Aging↗
PubMed1984

Topical treatment of periocular basal cell epithelioma with solcoderm.

25 patients with 29 histologically confirmed periocular basal cell epitheliomas were treated by topical application of Solcoderm, a solution of organic and inorganic acids and ions. The cure rate of the 29 lesions, which were followed for a mean period of 32 months, was 80%. The overall cure rate following second Solcoderm treatment of the 6 recurrent lesions was 96.7%. The cosmetic and functional results were excellent and there were no serious complications and side effects.

Acetates↗
PubMed1984

Arachidonic acid metabolism by retinas of rats with streptozotocin-induced diabetes.

Arachidonic acid metabolism via the cyclooxygenase pathway and the effects of aspirin and indomethacin were studied in whole retinas of rats with streptozotocin-induced diabetes. Diabetes was induced by intravenous injection of streptozotocin (60 mg/kg) and the animals were examined 5-6 weeks later. Whole retinas of nondiabetic and diabetic animals were incubated for 1 1/2 hours, and the amounts of prostacyclin and prostaglandin E2 (PGE2) accumulated in the media were measured. The amounts of PGE2 in the media of diabetic retinas was significantly lower than levels in media of nondiabetic group. However, the amounts of prostacyclin accumulated in the media of nondiabetic and diabetic retinas did not differ significantly. Addition of arachidonic acid (A.A.) to the incubation media caused an enhancement in the amounts of PGE2 and prostacyclin in the incubation media of both diabetic and nondiabetic retinas. Addition of indomethacin or aspirin to the incubation media caused a reduction of prostacyclin and PGE2 levels in the media of both groups.

Animals↗
PubMed1984

Eye injuries and ocular protection in the Lebanon War, 1982.

There was a high incidence of ocular trauma (6.8% of all casualties) in the Lebanon War, 1982, which is similar to the rates in previous Arab-Israeli wars. Combat in the Lebanon War consisted of both armored warfare and infantry operations, with much of the fighting taking place in built-up areas. Consequently, there were two main types of ocular injuries: perforating eye injuries caused by the small high-velocity missiles that characterize armored combat, and a wide range of injuries to the eye caused by ricochets during combat in built-up areas. The latter injuries varied in severity from complete destruction of the eye to minor corneal erosions. Not a single eye was injured in soldiers who had ballistic protective goggles properly placed over the eyes at the time of injury. Most of the ocular trauma could have been prevented had the goggles been in universal use. A considerable degree of eye protection is also afforded by ordinary ophthalmic eyeglasses.

Eye Foreign Bodies↗
PubMed1984

Severe combat eye injuries in the Lebanon War, 1982.

The findings, treatment and follow-up of 21 severe, blunt and perforating ocular injuries that occurred during combat in the Lebanon War, 1982, are presented. The diagnostic and therapeutic approaches to complex and severe ocular injuries are discussed. The patients were followed up for 1 year and the long-term effects of the injuries on their eyesight are described.

Adult↗
PubMed1983

Effects of low-level energy lasers on the healing of full-thickness skin defects.

Effects of low-level helium-neon laser radiation were compared on (1) wounds that closed primarily by contraction and (2) the breaking strength of straight-line incisions. Circular full-thickness skin defects in rabbits received dosages of 1.1 J/cm2 during a 30-min exposure every third day, and 2.2 J/cm2 during a 3-min exposure twice daily until wound closure. No significant differences in healing were observed between laser-treated wounds and untreated control wounds. Conversely, rat skin incisions exposed to 2.2 J/cm2 for 3 min twice daily for 14 days demonstrated a 55% increase in breaking strength over control rats (p less than 0.01); 28 days postoperatively, this difference in breaking strength diminished to a nonsignificant 16% increase over the control rats. Increasing the dosage to 4.5 J/cm2 yielded a nonsignificant 17% increase over the control rats 14 days postoperatively. HeNe laser irradiation of wounds increases certain aspects of healing in the early stages, but not to such a degree as to be clinically applicable. More detailed research is indicated to obtain optimal exposure levels necessary to accelerate wound healing significantly.

Animals↗
PubMed1983

The relative proportions of lysosomal enzyme activities in bovine retinal pigment epithelium.

The lysosome fractions from bovine retina, liver and retinal pigment epithelium were isolated by subcellular fractionation and compared with regard to the relative proportions of several hydrolytic enzyme activities. It was found that the lysosome fraction of the retinal pigment epithelium is more than three times as active as the lysosome fractions from other tissues in degrading the rhodopsin of photoreceptor (rod) cell outer segments. This proteolytic activity is attributable to a cathepsin D-like proteinase, and the possible biochemical bases for its increased activity in the pigment epithelium are discussed, including interaction with phospholipase A. It is suggested that the lysosomes of the retinal pigment epithelium are specialized in their content of hydrolytic enzymes for the degradation of photoreceptor cell outer segments.

Animals↗
PubMed1983

Indications for the role of the immune system in the pathogenesis of corneal alkali burns.

We produced alkali burns (1.5 N NaOH) in the right eyes of 63 mice. Three weeks later the left eye of each mouse was similarly burned. All eyes were followed up weekly for 4 weeks after the burn and were graded according to the severity of the lesion. The lesions developed much faster and were more severe in the left eyes. These results suggest that the body's immune mechanism participates in the pathogenesis of alkali corneal burns and adversely affects the development of this condition.

Alkalies↗
PubMed1983

Urokinase-treatment of fresh laser irradiation-induced vitreous hemorrhage.

Using a ruby laser, we induced vitreous hemorrhage in each eye of 12 rabbits. On the following day either 25,000 Ploug units of urokinase or saline were injected into the eyes of each rabbit. Urokinase did not accelerate the absorption of blood from the vitreous but prevented the development of severe vitreous fibrosis which replaced the hemorrhage in seven of the control eyes.

Animals↗
PubMed1982

Ocular injuries in Malawi.

A survey was made of 205 patients admitted to hospital for ocular trauma in Malawi in south-east Africa from January 1976 to December 1977. Results of the survey show that eye trauma is a relatively common problem in this developing country, occurring most frequently in children, young adults, and males. Most eye injuries in Malawi occurred under domestic circumstances; the major cause of ocular trauma was associated with chopping and gathering wood. Industrial injuries were rare. The most common injury was contusion and the most frequent complication was traumatic cataract. Most treated eyes retained useful vision.

Accidents, Home↗
PubMed1982

Epithelial invasion of the anterior chamber following repeated keratoplasty.

A 17-year-old man underwent five perforating keratoplasties. The first operation was due to keratoconus and the first two grafts were rejected. Five months after the second operation, the patient complained of severe ocular pains and retrocorneal and iris membranes were noted. Because of acute glaucoma, a peripheral iridectomy was performed, followed by by trabeculectomy due to persistent high pressure. After the third keratoplasty, a diagnosis of epithelial downgrowth was histopathologically established. Fourth and fifth keratoplasties were done because of corneal abscesses, this time combined with membrane peeling from the vitreous cavity. Epithelial cells were diagnosed again in histopathological examination of material removed from the vitreous. The rarity of epithelial downgrowth after surgically uncomplicated keratoplasty and the importance of the symptom of severe disabling pain are stressed.

Abscess↗
PubMed1982

Senile cataracts and myopia.

A retrospective survey of 32 persons with myopia and 38 persons with emmetropia who had been operated on at two US Army hospitals on the California coast showed that the persons with myopia who had worn eyeglasses for at least 20 years underwent cataract extraction at a significantly (P less than .00005) older age than the persons with emmetropia (median age at the time of the operation was 70 years, compared with 64 years). These results support the theory that some protection against solar ultraviolet radiation is offered the eyes by eye wear worn continuously and that solar ultraviolet radiation may be a contributing factor in the formation of human senile cataracts.

Adult↗