Search PubMed⌕ Search

Biomedical subjects

M Belkin

Publications and source records attributed to M Belkin.

At least 145 records · Page 8Linked to original sources
PubMed1987

Intelligence, education, and myopia in males.

We conducted a nationwide study of the relationship among refractive error, intelligence scores, and years of schooling in 157,748 males aged 17 to 19 years. We found a strong association of myopia with both intelligence and years of school attendance. The prevalence of myopia was found to be significantly higher in the more intelligent and more educated groups. By fitting models of logistic regressions, we worked out a formula expressing the relationship among the rate of myopia, years of schooling, and intelligence level. We found that years of schooling and intelligence weigh equally in the relationship with myopia.

Adolescent↗
PubMed1987

Effects of low-energy He-Ne laser irradiation on posttraumatic degeneration of adult rabbit optic nerve.

Axons of the mammalian peripheral and central nervous systems degenerate after nerve injury. We have recently found that He-Ne laser irradiation may prevent some of the consequences of the injury in peripheral nerves of mammals. In the present study, the efficacy of the laser in treating injured neurons of the mammalian CNS was tested. Optic nerves of adult rabbits were exposed daily for 8-14 days to He-Ne laser irradiation (14 min, 15 mW) through the overlying muscles and skin. As a result of this treatment, the injured nerves maintained their histological integrity, which is invariably lost in injured mammalian CNS neurons.

Animals↗
PubMed1987

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↗
PubMed1987

Prostaglandin metabolism and intraocular pressure.

The plasma lipid alterations characteristic of essential fatty acid deficiency (EFAD) generally appear one to two weeks after the initiation of fat free parenteral nutritional (PN), and may be associated with a reduction in prostaglandin (PG) formation. In the present study the relationship between exclusion of fat from the diet and changes in intraocular pressure (IOP) and PGE2 plasma levels were studied in 28 patients. The results indicated that three weeks after the omission of dietary fat a significant reduction in IOP levels occurred which persisted throughout the follow-up period of 7 (SD 1.2) weeks. Plasma PGE2 levels were also significantly reduced in patients on fat free PN for three weeks as compared with levels measured while patients were on a fat containing diet. This clinical observation is not yet understood and might be related to changes exerted by fatty acid deficiency.

Adult↗
PubMed1986

Intra-arterial fibrinolytic therapy. Efficacy of streptokinase vs urokinase.

This study is a retrospective comparison of the results in 25 low-dose, intra-arterial streptokinase and 12 low-dose intra-arterial urokinase infusions for thromboembolic disease. Intra-arterial streptokinase was successful in 50% of infusions and was marked by significant abnormalities in the coagulation criteria. There was a high incidence of major and minor bleeding (48% overall), which could be attributed to systemic effects of the drug. Urokinase was successful in 100% of infusions, and showed no significant effects on systemic coagulation criteria. There were also fewer complications during urokinase infusion. The average pharmacy cost for a course of intra-arterial streptokinase was $165, while urokinase cost $1142. Despite the significant difference in expense, the increased efficacy and safety of urokinase make it the preferred agent for intra-arterial infusion. Theoretical reasons for the increased effectiveness of urokinase are discussed.

Adult↗
PubMed1986

Further evidence for the involvement of immunoregulatory processes in corneal alkali burns: effects of immunosuppression and convalescent serum.

Alkali burns were produced in one eye of a group of mice. Two, 3 and 4 weeks later the second eye of each mouse was similarly burned. The rate of perforation in the second-burned eyes was significantly higher than in the first eye. This effect was abolished by immunosuppressing the animals before the burning of the first eyes. This potentiation effect of an ocular burn on subsequent ones is transferable to other mice by intraperitoneal administration of convalescent serum prepared from mice that were previously burned. This evidence suggests that ocular alkali burns cause the appearance in the circulation of antigens not previously present there. The antibodies produced against these antigens exacerbate the subsequent burn lesion and perhaps also the condition of the original burn.

Alkalies↗
PubMed1985

Regenerating fish optic nerves and a regeneration-like response in injured optic nerves of adult rabbits.

Regeneration of fish optic nerve (representing regenerative central nervous system) was accompanied by increased activity of regeneration-triggering factors produced by nonneuronal cells. A graft of regenerating fish optic nerve, or a "wrap-around" implant containing medium conditioned by it, induced a response associated with regeneration in injured optic nerves of adult rabbits (representing a nonregenerative central nervous system). This response was manifested by an increase of general protein synthesis and of selective polypeptides in the retinas and by the ability of the retina to sprout in culture.

Animals↗
PubMed1985

Combined oculopneumoplethysmography and duplex scan. Use in the noninvasive cerebrovascular laboratory examination.

To determine the relative merits of oculopneumoplethysmography (OPG) (Gee) and duplex scanning of the carotid arteries, a retrospective analysis was made of 93 patients in a 12-month period who underwent noninvasive carotid studies followed by carotid angiography. The results for the duplex scan were 91% sensitivity, 86% specificity, and 89% overall accuracy in evaluation of 184 arteries. The OPG results were 59% sensitivity, 90% specificity, and 74% accuracy when applied to individual arteries. The sensitivity of OPG increased to 77% when applied to disease in the patient rather than in individual arteries. Analysis of cases in which the duplex scan and OPG were in agreement and disagreement suggested an important role for the OPG test despite its inferior accuracy compared with the duplex scan alone. The predictive value of an abnormal duplex scan result was 98% when the OPG was also abnormal, whereas it was 81% when the OPG was normal. The predictive value of a normal duplex scan result was 93% when the OPG was also normal, whereas it was 60% in those cases where the OPG was abnormal. We believe that the duplex scan should be the basic noninvasive evaluation of cerebrovascular disease, although the OPG continues to provide important information.

Arterial Occlusive Diseases↗
PubMed1985

A new transorbital surgical approach to the rabbit's optic nerve.

This work describes a surgical approach which establishes the rabbit's visual system as an experimental model for studying CNS regeneration. Using this model, the optic nerve, its cell bodies, and the axons, are easily accessible through an orbital approach, without the need for craniotomy and brain retraction. This surgical approach allows transplantation and 'wrap around' implantations of nerve segments from xenogeneic and syngeneic systems and diffusible substances derived from them, respectively. Furthermore, it enables studies aimed at determining deficiencies in mammalian CNS and investigating methods of augmentating mammalian CNS regeneration.

Animals↗
PubMed1985

Alterations in mRNA translation products associated with regenerative responses in the retina.

Translation products of mRNA from retinas of goldfish optic nerve (representing a regenerative CNS) and adult rabbit optic nerve (representing a nonregenerative CNS which can be induced to express regenerative characteristics) were examined by one- and two-dimensional gel electrophoresis. Translation products from retinas of the regenerating goldfish optic nerve included polypeptides barely detectable in the translation products of mRNA derived from retinas of uninjured controls. Some of these polypeptides, of apparent molecular weights 24-28, 43-49, 60, and 65 kilodaltons can be considered as growth-associated polypeptides described in other regenerative and developing systems. The induction of regeneration-associated characteristics in the injured adult rabbit optic nerve, "implanted" with diffusible substances from nonneuronal cells of regenerative or growing nerve, is reflected by changes in the mRNA translation products of the retina. Among such translation products are those of the following molecular weights: 16-18, 28, 32-35, 43-47, and 56-60 kilodaltons, and some higher-molecular-weight species.

Animals↗
PubMed1985

A model of corneal re-endotheliazation after surgical trauma.

A model for simulating the endothelial damage caused by surgery is described. The model consists of the introduction of a specially constructed instrument into the anterior chamber and using it for scraping the endothelium of a pre-determined, precisely quantifiable area of cornea. The process of healing of the scraped cornea can be followed and measured accurately by biomicroscopy, specular microscopy and histological techniques. The model can be used to study the qualitative and quantitative aspects of endothelium healing and the effects of the various endogenous, exogenous and iatrogenic factors on this process. The preliminary data presented shows that the healed endothelium consists of larger and less densly packed cells. The cell density is reduced by 43.3% after one scraping of 57% of the endothelium and by 69.2% after two such operations. Prolonged mild traumatic iritis causes the appearance of endothelial cells with incongruous shapes.

Animals↗
PubMed1985

Pterygium, solar ultraviolet radiation and myopia.

A retrospective study of 93 patients who underwent pterygium excision revealed a low prevalence of myopia in comparison with normal population. These results support the theory that solar ultraviolet radiation is a contributory factor in the formation in pterygium and some protection against this radiation is afforded by continuously worn myopic correction.

Female↗
PubMed1985

Diagnosis and localization of intraocular foreign bodies by computed tomography.

Computed Tomography (CT) is the only imaging modality whereby bone and anatomical soft tissue structures are clearly defined. Detection of intraocular foreign bodies (FBs) can be easily obtained by scanning in the axial plane. For the precise localization of FBs, information in two planes is necessary; this is usually achieved by adding a CT study in the coronal plane to the axial plane study. When using a superimposed grid with millimeter calibration on a zoom orbital scan, the accurate location can be calculated. This contribution is of the utmost importance in deciding upon the appropriate approach when surgical removal is indicated.

Adolescent↗