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Biomedical subjects

M D Brown

Publications and source records attributed to M D Brown.

At least 235 records · Page 13Linked to original sources
PubMed1988

AIDS and children.

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Acquired Immunodeficiency Syndrome↗
PubMed1988

Spermicidal condoms.

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Acquired Immunodeficiency Syndrome↗
PubMed1987

1,2-Dimethylhydrazine-induced alterations in colonic plasma membrane fluidity: restriction to the luminal region.

Recently, work in this laboratory has shown that changes in the 'dynamic' component of fluidity, lipid composition and phospholipid methylation activity of distal colonic brush-border membranes could be detected after administration of 1,2-dimethylhydrazine to rats of the Sherman strain for 5-15 weeks, i.e., before the development of colon cancer. The present experiments were therefore conducted to: determine whether similar 'premalignant' biochemical changes could be detected in basolateral membranes of Sherman rats treated with this agent; and clarify the relationship of these membrane changes to the malignant transformation process by examining the effect of 1,2-dimethylhydrazine on these biochemical parameters in colonic antipodal plasma membranes of rats of the Lobund-Wistar strain. This particular strain of rats has previously been shown to be total resistant to the induction of tumors by 1,2-dimethylhydrazine. The results of the present experiments demonstrate that similar biochemical alterations could not be detected in the colonic plasma membranes prepared from either strain of rat treated with 1,2-dimethylhydrazine. These data support the contention that the prior biochemical membrane alterations noted in brush-border membranes of 1,2-dimethylhydrazine-treated animals are, in fact, related to the malignant transformation process and, furthermore, are confined to the luminal surface of distal colonic epithelial cells.

1,2-Dimethylhydrazine↗
PubMed1987

Penile tumors: their management by Mohs micrographic surgery.

Penile tumors represent a difficult group of neoplasms requiring effective and curative treatment while minimizing tissue loss to prevent cosmetic and functional deformity. Over the past 6 years, we have treated 20 patients with penile cancer utilizing the fresh tissue technique of Mohs micrographic surgery. Tumors were excised with an average of 2.25 stages. Most defects (80%) were allowed to heal by second intention. Since surgery, four patients have developed metastatic disease in their regional lymphatic system, and one patient has died from metastatic spread. One patient has developed local recurrence. Micrographic surgery is a very useful treatment modality for patients with penile tumors. Patients with SCC of the penis should be considered for elective regional lymph node biopsy and/or dissection in conjunction with micrographically controlled excision of the primary tumor.

Adult↗
PubMed1987

Intraluminal calcium modulates lipid dynamics of rat intestinal brush-border membranes.

The present investigations were performed to evaluate whether calcium modulates the physical state and lipid composition of rat enterocyte plasma membranes in vivo. Ca2+ [CaCl2 (50 mM) in NaCl] or NaCl (vehicle control) was administered to rats by intraluminal (gavage) or intraperitoneal routes. Sixty minutes later, brush-border (BBM) and basolateral membranes (BLM) were prepared from the proximal small intestine. By use of the fluorophores, DL-2-(9-anthroyl)-stearic acid (2-AS), DL-12-(9-anthroyl)-stearic acid (12-AS), and 1,6-diphenyl-1,3,5-hexatriene (DPH), steady-state fluorescence polarization studies demonstrated that intraluminal calcium decreased the fluidity of BBM but not BLM compared with their respective vehicle controls. These alterations in fluidity could, at least in part, be attributed to the concomitant increase in sphingomyelin content and the sphingomyelin/lecithin ratio (mol/mol) observed in the BBM prepared from calcium-gavaged rats. To evaluate the mechanism for these lipid alterations, enzyme activities involved in sphingomyelin synthesis and degradation were measured and revealed an increase in sphingomyelin synthase and a decrease in sphingomyelinase in BBM prepared from calcium-gavaged rats. In contrast, intraperitoneal administration of calcium failed to influence membrane fluidity, lipid composition, or these enzymatic activities in either BBM or BLM.

Animals↗
PubMed1987

Retraction.

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Retraction Notice↗
PubMed1986

Cyclosporine improves psoriasis in a double-blind study.

In a double-blind trial, 21 patients with severe plaque psoriasis were randomly assigned to receive oral cyclosporine, 14 mg/kg/d, or its vehicle. After four weeks of therapy the 11 cyclosporine recipients had the following response to treatment: two had total clearing and six improved markedly, two moderately, and one minimally; whereas ten vehicle-treated patients showed no change or minimal improvement. Vehicle-treated patients, after a switch to cyclosporine for four weeks, demonstrated impressive improvement similar to that seen in patients who initially received only cyclosporine. Moderate or marked improvement or total clearing was noted in 17 (81%) of 21 and 20 (95%) of 21 after one and four weeks of therapy, respectively. Mitotic figures and leukotriene B4 levels in lesions decreased 86% and 64%, respectively, after seven days of cyclosporine therapy. Mononuclear (including activated T cells) and polymorphonuclear leukocyte infiltrates were markedly reduced in lesions of all patients after seven days of cyclosporine therapy. These results suggest that psoriasis may have an immunologic basis mediated by activated T cells and/or other immune cells; if a long-term regimen with a favorable efficacy-side effect ratio can be determined, cyclosporine would be a significant advance in the treatment of psoriasis.

Adult↗
PubMed1986

Distribution of glycosphingolipids of monkey small and large intestinal mucosa.

The ganglioside and neutral glycosphingolipid composition of adult monkey small and large intestinal mucosa were characterized and compared. GM3, GM2 and GD1A were found to be the principal gangliosides in each of these tissues. Dihexosylceramide was the major neutral glycosphingolipid of both organs. The total content of gangliosides and neutral glycolipids/ceramide, however, was ca. four-fold and two-fold higher, respectively, in small intestinal than colonic mucosa. While all glycosphingolipids examined contained hydroxy and nonhydroxy fatty acids, the former fatty acids accounted for 60-90% of the total fatty acids in both organs. Sphingosine was the predominant long chain base of ceramide, mono-, di-, tri- and tetrahexosylceramide, whereas phytosphingosine was the major base of GM3 in both tissues. The results of these studies demonstrate that while many similarities of monkey small and large intestinal glycosphingolipids exist, qualitative and quantitative differences are present along the length of the monkey gut. These differences may be at least partially responsible for certain of the well-recognized variations in normal physiological and pathological processes that occur in these organs.

Animals↗
PubMed1986

Retraction.

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Retraction Notice↗
PubMed1986

Effect of gonadotrophin releasing hormone on conception rate in repeat-breeder dairy cows.

The effect of gonadotrophin releasing hormone (GnRH) on conception rate was studied in 961 repeat-breeder cows in five California dairy farms. Cows were injected with GnRH or saline at the time of the fourth insemination. All breeding was by artificial insemination (AI) using frozen semen from two bulls. Conception rate for GnRH-treated cows was higher than for controls (47.0 vs 37.7%, P < 0.01). There was no significant difference in conception rate between the two bulls or among five AI technicians. How GnRH acts upon fertility in repeat-breeder cattle has not been determined.

Journal Article↗
PubMed1986

Female-only intrapartum nurses: policy and the law.

Administrators of facilities that deliver babies should consider allowing carefully selected, qualified, and competent male staff nurses to be employed in labor and delivery. Examples of present and past male intrapartum nurses are presented.

Delivery, Obstetric↗
PubMed1986

Chemonucleolysis (discolysis) with collagenase.

Fifty-four patients with proven lumbar disc displacement were treated by intradiscal injection of collagenase (Nucleolysin) between April 1981 and January 1984. Follow-up by history and physical examination, phone survey, and/or mail survey shows 72% success rate (excellent, good, and fair) and 28% poor or unsuccessful results. No patient was made worse by the treatment. Success rate was greater in patients older than the age of 50 years, male patients, and patients with pain complaints of longer than 4 months' duration. The presence of a list and/or crossed straight leg raising and/or straight leg raising positive less than 30 degrees was associated with a poor prognosis. Discography prior to collagenase injection did not compromise the outcome of treatment. Postinjection changes in the CT scan correlated with a satisfactory outcome of treatment. Findings at surgery in patients who failed to obtain relief following collagenase injection did not show a specific deleterious effect of the enzyme, nor were the expected results from surgery compromised by a previous unsuccessful intradiscal collagenase injection.

Adult↗