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Biomedical subjects

S Cotton

Publications and source records attributed to S Cotton.

10 recordsLinked to original sources

Copper transport.

In adult humans, the net absorption of dietary copper is approximately 1 mg/d. Dietary copper joins some 4-5 mg of endogenous copper flowing into the gastrointestinal tract through various digestive juices. Most of this copper returns to the circulation and to the tissues (including liver) that formed them. Much lower amounts of copper flow into and out of other major parts of the body (including heart, skeletal muscle, and brain). Newly absorbed copper is transported to body tissues in two phases, borne primarily by plasma protein carriers (albumin, transcuprein, and ceruloplasmin). In the first phase, copper goes from the intestine to the liver and kidney; in the second phase, copper usually goes from the liver (and perhaps also the kidney) to other organs. Ceruloplasmin plays a role in this second phase. Alternatively, liver copper can also exit via the bile, and in a form that is less easily reabsorbed. Copper is also present in and transported by other body fluids, including those bathing the brain and central nervous system and surrounding the fetus in the amniotic sac. Ceruloplasmin is present in these fluids and may also be involved in copper transport there. The concentrations of copper and ceruloplasmin in milk vary with lactational stage. Parallel changes occur in ceruloplasmin messenger RNA expression in the mammary gland (as determined in pigs). Copper in milk ceruloplasmin appears to be particularly available for absorption, at least in rats.

Adult

The adenoma-carcinoma sequence and prospects for the prevention of colorectal neoplasia.

Colorectal adenomatous polyps are thought to be precursors of colorectal cancer. This article reviews the evidence for the adenoma-carcinoma sequence and possible interventions in regard to the prevention of colorectal cancer. Although there is no direct evidence to support the adenoma-carcinoma sequence, there is considerable indirect evidence from a range of epidemiological, histopathological, and molecular genetic studies. Sigmoidoscopy and fecal occult blood testing may offer the potential for secondary prevention, but screening based on either of these methods in the general population has not yet been shown conclusively to be effective and efficient. Although the importance of dietary factors in the etiology of colorectal lesions suggests that there may be potential for primary prevention through dietary modification or nutrient supplementation, few trials have been completed to date. Although observational studies suggest that the incidence of colorectal cancer may be reduced by as much as 50% by the use of aspirin or other nonsteroidal antiinflammatory drugs (NSAIDs), further research is needed to determine the effects of individual NSAIDs and the appropriate prophylactic dose and to develop new NSAIDs with reduced gastrointestinal side-effects. Other strategies for primary prevention could focus on interventions to increase physical activity levels, to encourage smoking cessation, and to moderate alcohol consumption. Potential areas for further research are proposed.

Adenoma

Voluntary screening program for prostate cancer: detection rate and cost.

In a community-wide screening program conducted in Jacksonville, Florida, 564 participants received free screening for prostate cancer. Frequency of positive results of prostate-specific antigen measurement and digital rectal examination was comparable to that found in similar programs in other communities. The estimated cost for each participant was $231, and the cost to discover each cancer was $7,240. If one also includes initial therapy in cost estimates, then the cost per participant was $520, and the cost to find and treat each patient was $16,300. The value of screening for prostate cancer must be judged by treatment outcome and underlying costs.

Aged

Treatment of the anemia of chronic renal failure with subcutaneous recombinant human erythropoietin.

PURPOSE: The purpose of this study was to determine the efficacy of recombinant human erythropoietin (rHuEPO) given subcutaneously three times/week in patients with chronic renal failure and anemia (predialysis). PATIENTS AND METHODS: Eleven patients with predialysis chronic renal failure participated in a double-blind, placebo-controlled study of subcutaneously administered erythropoietin. For 12 weeks, patients received either rHuEPO 100 mu/kg body weight three times/week subcutananeously or a placebo. After 12 weeks of placebo, patients now also received rHuEPO in a dose up to 150 mu/kg three times/week until target hematocrit was achieved. Throughout the study, blood pressure was monitored closely and blood work was obtained regularly for hemoglobin, hematocrit, reticulocyte count, and iron profile determinations. RESULTS: At 12 weeks, the hematocrit of the treated group had risen from 29% +/- 2% to 35% +/- 2% (p less than 0.001). The placebo group baseline hematocrit was 28% +/- 2% and at 12 weeks 26% +/- 2% After 12 weeks of rHuEPO therapy, the hematocrit of the prior placebo group was 32% +/- 2% (p less than 0.001 versus baseline). No significant change in biochemical parameters was noted. Mean blood pressure values were comparable before and after treatment. All protein ultimately required iron supplementation. In two patients, the rate of progression of renal failure appeared to increase as their hematocrit rose and rHuEPO was discontinued. CONCLUSIONS: It is concluded that rHuEPO given subcutaneously is an effective and safe therapy for patients with chronic renal failure who are anemic and who are not receiving dialysis.

Adult

Evaluation of the National Acoustic Laboratories' new hearing aid selection procedure.

This study evaluated the National Acoustic Laboratories' (NAL) new formula for prescribing the gain and frequency response of a hearing aid. The frequency response prescribed for 44 clients (67 fitted ears) was compared with a series of variations having increased or decreased low-frequency and/or high-frequency emphasis. The evaluations consisted of paired-comparison judgments of the intelligibility of speech in quiet and the pleasantness of speech in noise. There were only 4 ears (6%) where a comparison response was more intelligible than the NAL response, but there were 16 ears (24%) where one of the comparison responses was more pleasant. On the average, hearing aid gain that was used by each subject agreed closely with prescribed gain. These trends were not affected by audiogram configuration, experience in aid usage, or type of aid limiting. The formula was found to be highly effective, but there were some cases where a change in aid prescription was indicated. A simple evaluation procedure using paired-comparison judgments is proposed for detecting such cases.

Aged

Antiplasmin activity of electrophoretically separated human serum fractions.

The antiplasmin which migrates electrophoretically with the alpha(2) globulins preponderates in effect over that of the alpha(1) migrating antiplasmin. This preponderance persists at physiological pH value in vitro and the significance of this finding is discussed. No evidence has been obtained of the existence of anti-urokinase activity in antiplasmin-free serum fractions.

Alpha-Globulins