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Biomedical subjects

K L Cohen

Publications and source records attributed to K L Cohen.

At least 19 recordsLinked to original sources
PubMed1992

A new, band-shaped and whorled microcystic dystrophy of the corneal epithelium.

Five family members and three unrelated patients (four women, four men, 23 to 71 years old) had a dystrophy of the corneal epithelium. Direct slit-lamp examination showed bilateral or unilateral, gray, band-shaped, and feathery opacities that sometimes appeared in whorled patterns. Retroillumination showed intraepithelial, densely crowded, clear microcysts. Light and electron microscopy disclosed diffuse vacuolization of the cytoplasm of epithelial cells in the affected area. Visual acuity was so reduced in three patients that abrasion of the corneal epithelium was performed. The corneal abnormalities recurred within months, with the same reduction in visual acuity as before. The corneal opacities were progressive in two patients but diminished noticeably in another after he began using a hard contact lens. We found no other ophthalmic irregularities or associated systemic abnormalities and no indication of drug-induced keratopathy.

Adult↗
PubMed1990

Lack of effect of clonidine and pentoxifylline in short-term therapy of diabetic peripheral neuropathy.

The goal of this study was to confirm or rule out anecdotal reports of beneficial effects of clonidine and pentoxifylline in the treatment of painful diabetic peripheral neuropathy. Clonidine was administered to 16 subjects at two dosage levels (0.1 and 0.2 mg/day) and was compared to placebo in a crossover design, with each phase lasting 4 wk. Either pentoxifylline (400 mg 3 times/day) or placebo was given to 21 subjects in a 12-wk trial. Discomfort was characterized and rated with a subjective pain score (range 0-20). There was a significant decrease in pain score from baseline with both active drugs (P less than 0.05), but this was no better than the response to placebo (P less than 0.30 for clonidine and P less than 0.95 for pentoxifylline). This study does not demonstrate a short-term benefit of either clonidine or pentoxifylline in the treatment of peripheral neuropathy.

Clonidine↗
PubMed1990

Cat endothelial morphology after corneal transplant.

The cat has been suggested as a superior model to evaluate penetrating keratoplasty and corneal endothelial damage and repair. Morphologic change is felt to be a sensitive indicator of endothelial stress response. We documented corneal thickness and endothelial morphometric parameters of eight cats before and after homograft penetrating keratoplasty using an Eisner contact glass. One-hundred-cell samples from preoperative and 6.18 +/- 0.57 weeks and 9.25 +/- 0.84 months (means +/- standard errors of the means) postoperative photomicrographs were computer analyzed. Cell density (cells/mm2), coefficient of variation of cell area, percent hexagonal cells, and mean figure coefficient were measured. Values are given as means +/- standard errors of the means. Preoperative coefficient of variation for area, 19.1 +/- 0.4, was significantly greater (22.0 +/- 1.0) six weeks after surgery. At nine months, cell density (1487 +/- 114) and percent hexagonal cells (59.6 +/- 2.1) were significantly less than six week values (cell density = 2053 +/- 201, percent hexagonal cells = 68.1 +/- 1.5) and preoperative values (cell density = 2395 +/- 94, percent hexagonal cells = 69.3 +/- 1.1). Thus there is evidence of polymegethism six weeks after surgery and persistent decreased cell density and pleomorphism nine months after surgery.

Analysis of Variance↗
PubMed1989

Intraocular lens explantation with and without penetrating keratoplasty.

We reviewed the records of 33 consecutive patients who had undergone intraocular lens (IOL) explantations for IOL-related complications. Results from 19 eyes that underwent penetrating keratoplasty at the time of explantation (pk eyes) were compared with the results from 14 eyes that underwent only IOL explantation (npk eyes). Uveitis was the most common indication for explantation in the npk eyes; frank bullous keratopathy was the most common in the pk eyes. Fifteen of the IOLs explanted from the pk eyes were anterior chamber IOLs, 13 of which were the semiflexible, closed-loop type. Ten of the npk eyes had anterior chamber IOLs explanted, six of which also were the semiflexible, closed-loop type. Visual acuities in the pk group were significantly worse than they were in the npk group, both before and after explantation. Based on this review, we conclude that if anterior chamber and iris-supported IOL complications occur and medical therapy fails, IOL explantation prior to the need for penetrating keratoplasty may improve visual acuity.

Aged↗
PubMed1989

Postoperative zygomycetes endophthalmitis.

Fungal endophthalmitis is an uncommon complication of intraocular surgery. We report, to our knowledge, the first case of a postoperative Zygomycetes endophthalmitis that occurred after uncomplicated phacoemulsification and the insertion of a posterior chamber intraocular lens. Diagnosis, in the presence of negative aqueous and vitreous cultures, was confirmed by immunofluorescence staining of an anterior chamber inflammatory mass. Successful treatment of the eye with 20 micrograms of intraocular amphotericin B (Fungizone) may have been made possible in part by the fact that the posterior capsule remained intact, keeping the eye bicompartmental.

Amphotericin B↗
PubMed1979

Thyroid function screening in psychiatric patients.

Abnormalities in levels of total thyroxine and thyroxine binding capacity were common in a group of 480 newly admitted psychiatric patients. The estimated free thyroxine (EFT4) level was elevated in 43 patients (9%). In 27 of these patients, the level of EFT4 became spontaneously normal, usually within a two-week period (acute "stress hyperthyroidism"). The level of EFT4 was decreased in 42 patients (9%). In 16 of these patients, the level became spontaneously normal; the etiology of this apparent acute hypolhyroidism is unclear. The yield of new cases of primary hyperthyroidism and hypothyroidism was low, but a presumptive diagnosis of secondary hypothyroidism was made in eight patients. In addition, nine patients with known thyroid disease were taking inadequate or excessive replacement therapy. Thyroid function screening tests are of value in psychiatric patients.

Adolescent↗
PubMed1979

Effect of phenylephrine on normal and regenerated endothelial cells in cat cornea.

Topical commercial phenylephrine HCl (Neo-Synephrine 10%) has been shown to cause an increase in corneal thickness and reversible vacuolization of corneal endothelial cells in rabbits. Using an in vivo model of regenerated corneal endothelial cells in the cat, we compared the cytotoxicity of phenylephrine-HCl 10% to regenerated and to normal, nonregenerated cells. Following removal of the epithelium, topical application of the drug causes the appearance of anterior and posterior bands of stromal edema and reversible vacuolization in both normal and regenerated endothelial cells. Phenylephrine was not more damaging to the regenerated cells. Polymorphonuclear leukocytes infiltrated between the regenerating cells 24 hr after treatment but did not appear to destroy them. Phenylephrine may therefore be implicated as a causative factor of corneal edema and postoperative inflammation.

Animals↗
PubMed1978

Incidence of pituitary tumors following adrenalectomy. A long-term follow-up study of patients treated for Cushing's disease.

The long-term follow-up of 21 patients who had undergone bilateral adrenalectomy for Cushing's disease has revealed eight definite and two suspected cases of pituitary tumors. The average time from adrenalectomy to the diagnosis of the pituitary tumor was 6 1/2 years, with a range of 1 1/2 to 12 years. The incidence of tumors in this study (38%) is higher than that reported by others and may reflect (1) that none of these patients received pituitary irradiation in addition to adrenalectomy, (2) the length of follow-up, and (3) the high index of suspicion and early diagnosis of pituitary tumors in recent years. These data raise the question of whether bilateral adrenalectomy alone is an acceptable form of therapy for Cushing's disease. For patients treated in this way, a life-long commitment should be made to undergo annual reexamination for the possible occurrence of a pituitary neoplasm.

Adenoma↗
PubMed1978

Contribution of human somatomedin activity to the serum growth requirement of human skin fibroblasts and chick embryo fibroblasts in culture.

Although purified human somatomedins and related peptides have been shown to stimulate growth-related processes in cultured human skin fibroblasts, it is unknown whether the serum macromolecules required for the routine growth of human fibroblasts in culture include the somatomedins. To evaluate this question we have obtained sera from five GH-deficient patients before and after GH treatment and have compared these pre- and post-GH sera for their ability to stimulate [3H]thymidine incorporation into DNA and cell multiplication in the patients' own fibroblasts in culture. Subconfluent human fibroblasts demonstrated a dose-dependent increase in thymidine incorporation and cell number when exposed to human sera. Pre- and post-GH sera were equipotent. Partial purification of somatomedin activity by boiling sera at pH 5.5 diminished the level of thymidine incorporation to 10-20% of the level achieved with unboiled sera but did not unmask a difference between pre- and post-GH sera. In contrast to the results in human fibroblasts, boiled post-GH sera were 2- to 5-fold more potent than pre-GH sera in stimulating thymidine incorporation in chick embryo fibroblasts. Mixing experiments failed to demonstrate inhibition of thymidine incorporation by boiled pre-GH sera. Boiled post-GH sera also were twice as active as boiled pre-GH sera in stimulating multiplication of chick embryo fibroblasts and confirmed that thymidine incorporation reflected DNA synthesis. GH added directly to chick embryo fibroblasts did not stimulate thymidine incorporation. We conclude that despite the presence of specific receptors for somatomedin-like peptides on human skin fibroblasts, somatomedins are not a major component of the serum macromolecules required for the routine growth of human fibroblasts in culture. In contrast, in chick embryo fibroblasts, somatomedins do appear to constitute an important part of the serum macromolecules supporting cell growth.

Animals↗
PubMed1978

Ocular emergencies.

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Arterial Occlusive Diseases↗