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Biomedical subjects

M K Khan

Publications and source records attributed to M K Khan.

50 records · Page 3Linked to original sources
PubMed1979

Experience with pion radiotherapy.

Forty-one patients with a total of 86 tumors were treated with negative pimesons (pions) at the Los Alamos Meson Physics Facility (LAMPF) through December 31, 1977. An additional 30 tumors in the total patient population were treated with 100 kVp x-rays to assess comparative effects on skin nodules and 8 patients received additive photon or electron radiation to pion-treated portals. Of 52 evaluable tumors in 20 patients treated with pions only and followed for 3 to 22 months, 81% (42 tumors) completely regressed; 6% (3 tumors) partially regressed; and 13% (7 tumors) did not respond, although 5 of the 7 have shown no growth for 10 months. Of eight tumors in seven patients treated with a combination of pions and conventional radiation, three tumors showed complete response and five tumors showed partial response, though the resected specimens in two (one with complete and one with partial response) revealed no tumor microscopically. Reactions in normal tissues have been mild, with some patients exhibiting no normal tissue reaction, as compared with relatively marked tumor response.

Abdominal Neoplasms↗
PubMedDate not supplied

Risk of transmission of bovine spongiform encephalopathy to humans in the United States: report of the Council on Scientific Affairs. American Medical Association.

CONTEXT: The risk of possible transmission of bovine spongiform encephalopathy (BSE) in the United States is a substantial public health concern. OBJECTIVE: To systematically review the current scientific literature and discuss legislation and regulations that have been implemented to prevent the disease. METHODS: Literature review using the MEDLINE, EMBASE, and Lexis/Nexis databases for 1975 through 1997 on the terms bovine spongiform encephalopathy, prion diseases, prions, and Creutzfeldt-Jakob syndrome. The Internet was used to identify regulatory actions and health surveillance. DATA EXTRACTION: MEDLINE, EMBASE, and Lexis/Nexis databases were searched from 1975 through 1997 for English-language articles that provided information on assessment of transmission risk. RESULTS: Unique circumstances in the United Kingdom caused the emergence and propagation of BSE in cattle, including widespread use of meat and bonemeal cattle feed derived from scrapie-infected sheep and the adoption of a new type of processing that did not reduce the amount of infectious prions prior to feeding. Many of these circumstances do not exist in the United States. In the United Kingdom, new variant Creutzfeldt-Jakob disease probably resulted from the ingestion of BSE-contaminated processed beef. The United Kingdom and the European Union now have strong regulations in place to stop the spread of BSE. While BSE has not been observed in the United States, the US government has surveillance and response plans in effect. CONCLUSIONS: Current risk of transmission of BSE in the United States is minimal because (1) BSE has not been shown to exist in this country; (2) adequate regulations exist to prevent entry of foreign sources of BSE into the United States; (3) adequate regulations exist to prevent undetected cases of BSE from uncontrolled amplification within the US cattle population; and (4) adequate preventive guidelines exist to prevent high-risk bovine materials from contaminating products intended for human consumption.

American Medical Association↗
PubMedDate not supplied

Investigation by immunofluorescence of arterial lesions in rabbits on two different lipid supplements and treated with pyridinol carbamate.

Rabbits maintained on a pellet diet supplemented with cholesterol, or on a semi-synthetic diet containing beef fat but no added cholesterol, have been studied in relation to their development of hyperlipidaemia and of lipid-filled arterial lesions. The influence of pyridinol carbamate on animals on both diets was also examined but found to produce no significant effect. Animals on both diets developed a hyperlipoproteinaemia. In cholesterol-fed animals this developed quickly, became gross, and was characterized by the presence of an anomalous lipoprotein of very low density, large molecular size and abnormally high cholesterol content. Beef fat fed animals showed a more moderate hyperlipidaemia which developed more slowly and the lipoproteins qualitatively resembled those in normal rabbits. Differences in the rate and severity of development of aortic lesions between the two different dietary supplements were found to reflect differences in the duration and intensity of hyperlipoproteinaemia between the groups. Arterial lesions in cholesterol-fed animals were more extensive and contained larger numbers of fat-filled cells than those in beef fat-fed animals. Comparisons were made (in many cases on the identical section) between lesions treated with a fluorescein labelled antiserum to total rabbit serum low density lipoproteins (TLDL) and with a conventional lipid stain. Precise agreement was found between the distribution of lipid reacting with Oil red 0 and specific fluorescence for TLDL in endothelial cells, in extracellular deposits in the intimal ground-substance and in medial smooth muscle cells. But fat-filled cells in the intima and in reticulo-endothelial tissue showed variable immunofluorescent reactivity. The reason for this discrepancy is discussed. Agreement between the distribution of conventional lipid staining and specific immunofluorescence for TLDL was also found in extracellularly distributed material in arterioles and smaller vessels at certain sites. It is suggested that these results establish that rabbit TLDL serve as the vehicles transporting lipid into the experimental lesions, just as the homologous human lipoproteins do in human atherosclerosis.

Animals↗
PubMedDate not supplied

Survival among patients with ankylosing spondylitis: a life-table analysis.

A life-table analysis of survival was performed retrospectively on 56 white patients (49 males) with ankylosing spondylitis. The disease was diagnosed in these patients between 1934 and 1960 at a mean age of 35.2 yr. Patients were followed until December, 1975, a mean duration of 22 yr. The expected survival was calculated from life-tables for the United States population matched for sex, age, race, geographic area, and calendar year. For the first 10 yr of follow-up, there was no difference in the observed and expected survival. By 20 yr after diagnosis, 37 patients were observed to have survived whereas 46 were expected (p = 0.001). By 40 years after diagnosis, 16 were observed to have survived and 21 were expected (p = 0.063).

Actuarial Analysis↗