Biomedical subjects

S F Freedman

Publications and source records attributed to S F Freedman.

7 recordsLinked to original sources

PubMed1992

Pentoxifylline modulates deformability, F-actin content, and superoxide anion production of polymorphonuclear leukocytes from diabetic cats.

Capillary occlusion is an early event in the development of diabetic retinopathy, and white blood cells have recently been shown to be involved. We have shown previously that pentoxifylline improves deformability and decreases F-actin content of unstimulated polymorphonuclear leukocytes from normal human subjects. The purpose of this study was to determine if pentoxifylline would improve three properties of unstimulated polymorphonuclear leukocytes from diabetic cats. The measured parameters were mechanical (whole cell deformability), structural (F-actin content) and biochemical (rate of superoxide anion production). Chronic hyperglycemia was induced in three cats by partial pancreatectomy, and they were kept in poor glycemic control for at least 6 months prior to the study. Polymorphonuclear leukocytes were isolated and the entry time of individual passive cells was measured during aspiration into a 4-micron micropipette under constant suction pressure (-15 cmH2O). Deformability was defined as the inverse of the entry time. F-actin content of passive cells was measured by NBD-phallacidin labeling followed by flow cytometry. The rate of superoxide anion production was measured spectrophotometrically by superoxide dismutase-inhibitable cytochrome c reduction. Following incubation for 15 min with 0.1, 1.0 and 10.0 mM pentoxifylline, the average entry time of passive polymorphonuclear leukocytes was reduced from control by 11 +/- 5% (P = 0.045), 17 +/- 6% (P = 0.007), and 36 +/- 5% (P < 0.001), respectively. The F-actin content decreased by 0%, 4 +/- 0.6% (P < 0.001), and 10 +/- 3% (P < 0.001), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Actins↗

PubMed1992

Enhanced superoxide radical production by stimulated polymorphonuclear leukocytes in a cat model of diabetes.

This study examines the possibility that polymorphonuclear leukocyte activation, which can cause endothelial injury, may contribute to the capillary closure of diabetic retinopathy. To examine diabetes-related alterations in polymorphonuclear leukocyte activation, we compared the production of superoxide radical by these cells from normal and from diabetic cats that were maintained hyperglycemic. Polymorphonuclear leukocytes isolated from five diabetic and five normal cats were stimulated with 10 ng ml-1 phorbol myristate acetate, and the maximum rate of their superoxide radical production was measured spectrophotometrically. Stimulated polymorphonuclear leukocytes from diabetic cats generated more superoxide radical, at significantly higher rates, than did those from normals (3.32 +/- 0.33 and 2.50 +/- 0.41 nmol O2- min-1 10(-6) cells, respectively; P < 0.02). While addition of insulin or glucagon did not alter stimulated polymorphonuclear leukocyte radical production, glucose in high concentration did mildly impair its production in both groups. The exaggerated respiratory burst of polymorphonuclear leukocytes in diabetes could contribute to microvascular injury in the retina as well as in other tissues.

Animals↗

PubMed1992

Neurotologic manifestations of von Hippel Lindau disease.

Von Hippel Lindau disease is a hereditary phakomatosis characterized by congenital angiomatosis of the retina and cerebellum. This autosomal dominant syndrome exhibits variable penetrance and expressivity. Because of the marked clinical variability and sporadic age of onset, members of affected families must be counseled and screening protocols established. It has been recommended that initial screening include appropriate laboratory work, ophthalmologic and neurologic examination, radiologic evaluation of the CNS, and when appropriate, abdominal ultrasound. Follow-up examination should be annually with acute evaluations as focal signs and symptoms develop. With the help of technological advances and screening of family members, patients with vHL disease can live long, productive lives with reduced morbidity.

Adult↗

PubMed1992

Relapsing polychondritis.

Relapsing polychondritis is a rare disease of unknown etiology. It is characterized by progressive episodic recurring inflammation and degeneration of cartilaginous structures. The inflammation typically involves the cartilage of the ear, nose, trachea, and various peripheral joints. Treatment options most commonly involve the use of anti-inflammatory drugs and corticosteroids.

Biopsy↗

PubMed1990

Reinke's edema.

Reinke's edema is a benign disorder of the larynx. This pathological condition involving a potential laryngeal space is most often seen in middle-aged smokers, and has a slight female predilection. The diagnosis, histopathology, and conservative as well as surgical treatment modalities are discussed.

Adult↗

PubMed1989

Caustic ingestion.

Caustic ingestion is a serious medical problem affecting anywhere from 5,000 to 15,000 persons per year. The factors influencing the type and seriousness of the burn are numerous. Correct diagnosis using endoscopic technique is imperative in choosing the proper treatment whether it be medical or surgical. Stricture is the most common complication with rates from 2% to 4%.

Burns, Chemical↗

PubMed1988

Intraocular neurilemmoma arising from the posterior ciliary nerve in neurofibromatosis. Pathologic findings.

A classic neurilemmoma was found in the eye of a 31-year-old man with known neurofibromatosis. The pathologic features of this rare intraocular tumor were examined histologically, immunohistochemically, and ultrastructurally. Contiguity of the neurilemmoma with its nerve of origin, the long posterior ciliary nerve, was clearly demonstrated. Expansion of the nerve by proliferating Schwann's cells was present.

Adult↗