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Biomedical subjects

S J Bell

Publications and source records attributed to S J Bell.

At least 91 records · Page 5Linked to original sources
PubMedDate not supplied

Body composition changes in patients with human immunodeficiency virus infection.

Malnutrition characterized by weight loss and often extreme wasting generally develops when patients progress from infection with human immunodeficiency virus (HIV) to AIDS. There is evidence that before the development of AIDS, HIV-infected patients without weight loss show early signs of malnutrition, defined as an increase in the ratio of extracellular mass (ECM) to body cell mass (BCM). As part of a dietary intervention study, body composition measurement were obtained at baseline and after 6 wk in 18 patients with HIV infection and CD4 counts between 140 and 740 cells/mm3. Only one patient had a prior weight loss (3.7 kg); patients gained 2 pounds after 3 wk of dietary supplementation of 500 kcal daily. Bioelectrical impedance was used to measured body compartments. The average ECM/BCM ratio (0.77 +/- 0.13) was within the normal range (0.83 +/- 0.16) indicating the absence of malnutrition by this criterion. Most measurements of BCM (kg) approximated normal values, while several for BCM (kg) exceeded normal. BCM (kg) correlated poorly with the ECM/BCM ratio (r2 = 0.08; P = 0.11) in contrast to ECM (kg), which was well correlated (r2 = 0.82; P = 0.00). In addition, there was a significant correlation of body mass index (BMI) with the ECM/BCM ratio (r2 = 0.38; P = 0.00) and with ECM (r2 = 0.244; P = 0.003) indicating that overweight patients may be more likely to be considered malnourished than normal weight patients using this ratio. Without use of bioelectrical impedance, these subtle changes might be missed. Once significant weight loss has occurred coupled with decreases in BCM (kg), the ECM/BCM ratio may be more reflective of malnutrition. These conjectures will require prospective evaluation, but for now it seems reasonable to include bioelectrical impedance as a potentially useful tool in the evaluation of malnutrition in this population.

Adult↗
PubMedDate not supplied

Bioelectrical impedance methods in clinical research: a follow-up to the NIH Technology Assessment Conference.

In 1994, the National Institutes of Health (NIH) convened a Technology Assessment Conference "to provide physicians with a responsible assessment of bioelectrical impedance analysis (BIA) technology for body composition measurement." In 1997, Serono Symposia USA, Inc., organized an invited panel of scientists and clinicians, with extensive research and clinical experience with BIA, to provide an update. Panel members presented reviews based on their own work and published studies for the intervening years. Updates were provided on the single and multifrequency BIA methods and models; continued clinical research experiences; efforts toward establishing population reference norms; and the feasibility of establishing guidelines for potential diagnostic use of BIA in a clinical setting. This report provides a summary of the panel's findings including a consensus on several technical and clinical issues related to the research use of BIA, and those areas that are still in need of additional study.

Body Composition↗
PubMedDate not supplied

Model process for removal of caseins from milk of transgenic animals.

We describe a method for selective removal of caseins from milk. The method was developed as a model for transgenic milk processing. Raw cow milk spiked with nonmilk proteins was chosen as the model to resemble transgenic animal milk containing recombinant proteins. The most important elements of the process are (1) "deconstruction" of casein micelles in milk by destroying their Ca(2+) core using a chelating agent (EDTA), thus freeing any protein that might be entrapped in casein aggregates, and (2) "reconstruction" of micelles by providing them with a new Ca(2+) core, thus precipitating them away from the whey proteins, and the protein of interest. Calcium phosphate particles (CAP) were used to reform the disrupted casein micelles. The crystal clear supernatant fraction generated by this method provided >90% recovery and 6- to 13-fold concentration of the desired protein. Product-rich supernatant contained no detectable casein residues, as silver-stained SDS-PAGE and Western blot analyses demonstrated.

Animals↗
PubMedDate not supplied

Nutritional management of hypoglycemia.

PURPOSE: People with type 1 diabetes who follow an intensive management program have an increased risk of hypoglycemia, particularly overnight. New strategies for the nutritional management of hypoglycemia are essential. METHODS: The unique properties of foods that affect blood glucose are reviewed, with special attention to a new medical food bar designed to reduce the incidence of nocturnal hypoglycemia. RESULTS: All carbohydrate-containing foods affect blood glucose, but each causes a different rise in concentration. Consuming a variety of conventional foods with different glycemic indices can help control hypoglycemia. A new medical food bar that provides a sequential triphasic release of glucose from sucrose, protein, and uncooked cornstarch can help control blood glucose levels. CONCLUSIONS: Hypoglycemia can be avoided by consuming foods with varying glycemic indices. A new medical food bar that provides sequential release of glucose into the bloodstream may also help control blood glucose levels.

Diabetes Mellitus, Type 1↗
PubMedDate not supplied

Overview of gastrointestinal disorders due to diabetes mellitus: emphasis on nutritional support.

Gastrointestinal disorders associated with diabetes mellitus have a prevalence rate of 30 to 75%. The most prominent disorders are gastroparesis, diarrhea, and constipation. Severity of symptoms range from mild to severe with the most affected patients being at risk for the development of protein calorie malnutrition. An historical review of the major studies which defined the diagnosis, pathophysiology, and prevalence of these disorders is presented. Guidelines for accurate nutritional assessment, which is essential to the decision to initiate nutritional therapy in this difficult to assess population, are also included. Current methods devised for treatment of diabetic gastroparesis and related disorders are presented. Emphasis is placed on recent developments in nutritional support techniques which make it possible to meet the energy requirements of all such patients. Practical outlines for glucose control in patients receiving TPN or enteral feeding and guidelines for transitioning from parenteral feeding to an oral diet are also presented.

Diabetes Mellitus, Type 1↗
PubMedDate not supplied

Dietary fish oil and cytokine and eicosanoid production during human immunodeficiency virus infection.

BACKGROUND: Dietary fish oil (FO) has been shown to modulate the immune system. The purpose of this study was to explore the effects of FO supplementation on the production of dienoic eicosanoids and cytokines in patients with human immunodeficiency virus (HIV) infection. METHODS: This was a randomized, prospective, double-blind study that included homosexual males with HIV infection. Patients were asked to consume voluntarily five food bars daily containing FO (n = 10) or safflower oil (SO) (n = 9) for 6 weeks. At baseline and week 6, plasma was obtained to measure incorporation of omega-3 fatty acids. At baseline, week 3, and week 6, measurements were made of changes in dienoic eicosanoids and cytokines from lipopolysaccharide (LPS)-stimulated peripheral blood mononuclear cells (PBMC) or spontaneously releasing cells. RESULTS: In the FO group but not the SO group, there was increased incorporation of the omega-3 fatty acid docosahexaenoic acid (DHA) into the phospholipids of the fatty acids of the plasma. In the FO group, there was a significant decrease (p = .01) in 6-keto prostaglandin (PG) F1 alpha released from PBMC. There was a significant increase (p = .01) in interleukin (IL)-6 released from the PBMC in the FO group between baseline and week 3 and between week 3 and week 6. At week 6, there was significantly more IL-6 (p = .01) released from the PBMC in the FO group compared with the SO group. There was no change in CD4 cell counts by analysis of variance. CONCLUSIONS: The FO-containing food bars were well tolerated and allowed incorporation of omega-3 fatty acids to occur. Despite evidence of significant metabolic effects on eicosanoid and cytokine production, widespread clinical use of FO for HIV-infected patients is not warranted without further study, particularly given the trend toward a decline in CD4 cell numbers at this dose and with this type of fish oil.

Adolescent↗