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Biomedical subjects

M Belkin

Publications and source records attributed to M Belkin.

204 records · Page 12Linked to original sources
PubMedDate not supplied

Arterial reconstruction for lower limb ischemia.

The treatment of advanced atherosclerosis involving the lower extremities has undergone considerable evolution over the last several decades. Current strategies hinge on an appreciation of the natural history of disease, the overall health status of the patient, and an armamentarium of endovascular and open surgical reconstructive techniques that may be tailored to optimize outcome for the individual patient. Patients with aorto-iliac disease have a variety of available options with generally good results. For infrainguinal disease, surgical bypass using autogenous vein is the mainstay of interventional therapy and will remain so for the foreseeable future. Increasing medical and surgical challenges are presented by this population, particularly as aggressive medical treatment of risk factors leads to an ongoing decline in cardiovascular mortality, combined with a dramatic increase in the prevalence of diabetes. The future, which is now already at hand, will bring the application of genomics, with a potential for altering the progression of disease as well as extending the long-term benefits of reconstruction.

Blood Vessel Prosthesis Implantation↗
PubMedDate not supplied

Objective and subjective assessment of a new diffractive trifocal contact lens.

The purpose of this study was to test the objective and subjective performance of the Holo-Or Rigid Gas Permeable (RGP) Multifocal Contact Lens (MFCL), a new trifocal diffractive contact lens. Eleven experienced and two nonexperienced rigid gas permeable contact lens wearers participated in the study. Eleven patients were presbyopic (age 40-57) and two were aphakic (age 12 and 14). All patients were tested both with their best correction for distance and near and trifocal diffractive contact lenses. The follow-up period was 3-8 months. Subjective opinion was also assessed. Statistical analysis was performed using Student's t-test. We did not find any significant difference in visual acuity, measured at 6 m, 80 cm, and 40 cm, between best correction and Holo-Or diffractive contact lenses. Depth of focus improved to a statistically significant extent when using trifocal contact lenses. A small reduction in contrast sensitivity was observed when the patients used multifocal contact lenses. Overall satisfaction and comfort was good to excellent in 10 out of 13 patients. Two additional patients who used a bifocal model of the same contact lens design showed similar results. Holo-Or Trifocal Diffractive Contact Lenses are a satisfactory means of optical correction for patients with presbyopia or accommodative problems.

Adult↗
PubMedDate not supplied

Role of heparin in reducing skeletal muscle infarction in ischemia-reperfusion.

Heparin continues to be recommended in the clinical management of limb ischemia to prevent extension of distal vascular thrombosis and increased rates of limb loss. However, heparin may also be responsible for reduced skeletal muscle injury. Although its mechanism of action has not been fully evaluated, we have investigated the ability of heparin to minimize skeletal muscle injury associated with the ischemia-reperfusion syndrome in an in vivo canine gracilis muscle model. Our findings demonstrated a significant reduction in the amount of skeletal muscle infarction, microvascular permeability, and H+ ion accumulation cumulation after preischemic heparinization. Diffuse intravascular coagulation also has been observed in observed in this model which may be prevented or reduced by the anticoagulant properties of heparin when administered prior to ischemia. However, heparin's protective effect may be independent of its anticoagulant activity. Heparin is a polycomponent drug with non-anticoagulant properties which may serve to reduce cellular injury during ischemia and reperfusion in several different ways. Microvascular injury is decreased by the restoration of normal intimal negative charge and through the binding and resultant inactivation of histamine, bradykinin and other vasoactive amines. Heparin inhibits the complement cascade which is known to determine ischemic infarct size. Other factors of importance in determining the extent of skeletal injury include neutrophil activation, chemotaxis, enzyme release, and free oxygen radical generation, all of which are decreased or modulated by heparin. Heparin is a complex substance and much more remains to be learned about its anticoagulant and nonanticoagulant properties as well as its protective effects on skeletal muscle injury in ischemia-reperfusion syndrome.

Animals↗
PubMedDate not supplied

Hypothermia and controlled reperfusion: two non-pharmacologic methods which diminish ischemia-reperfusion injury in skeletal muscle.

The mechanisms of ischemia-reperfusion (I-R) injury in skeletal muscle remain controversial. We have previously reported two non-pharmacologic methods to salvage skeletal muscle from I-R injury, post-ischemic hypothermia and controlled reperfusion. In all experiments, both canine gracilis muscles were subjected to six hours of ischemia followed by one hour of reperfusion. Controlled reperfusion was achieved by partially occluding one gracilis artery to limit the rate of reperfusion blood flow to its pre-ischemic rate, while the contralateral artery was allowed to perfuse freely at a normal rate. Post-ischemic hypothermia was achieved by cooling one gracilis muscle to 21 degrees centigrade (hypothermic reperfusion) after 5 hours of warm ischemia, while the opposite gracilis muscle was maintained at ambient temperature (normothermic reperfusion). Both methods resulted in a significant diminution in muscle infarct and edema. The mechanisms by which this is accomplished are currently unknown, but may be related to a diminished inflammatory response to ischemia. This review of these methods suggests that the hyperemic rate of reperfusion blood flow is a significant factor in the pathophysiology of post-reperfusion edema, and that significant control of skeletal muscle reperfusion injury may be achieved by limiting the rate of reperfusion blood flow or by applying post-ischemic hypothermia.

Animals↗
PubMedDate not supplied

Childhood myasthenia gravis.

A boy aged five and a girl aged one year suffering from myasthenia gravis are described. Both cases had respiratory complications and were treated erroneously until their ptosis was noticed and the diagnosis of myasthenia gravis confirmed. The etiology, types, symptomatology, and treatment of the diseases are described. Attention of the pediatric ophthalmologists is called to the fact that they should consider myasthenia gravis in the differential diagnosis of ptosis and external ophthalmoplegia.

Adult↗