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Biomedical subjects

M E Keith

Publications and source records attributed to M E Keith.

3 recordsLinked to original sources

Immunonutrition.

The immune system is designed to protect the individual from foreign substances or organisms. It is expressed as cellular and humoral immunity. The former is dependent upon T lymphocytes and the latter on B lymphocytes, which become plasma cells and secrete antibodies. The immune system can be influenced by protein-energy malnutrition (PEM) and by catabolic illnesses such as sepsis and trauma, which in turn cause PEM. Specific trace element and vitamin deficiencies can also alter the immune state. However, overnutrition and obesity can also influence immune mechanisms. Obesity can promote the development of diabetes, which can alter the immune state. Finally, immunity becomes less effective with ageing and this process is enhanced by associated malnutrition.

Animals↗

Tubocurarine chloride inhibits rod outer segment shedding in the frog retina.

The cholinergic postsynaptic neuromuscular blocker, tubocurarine chloride (curare), attenuates the rod shedding response of the frog in a dose-dependent manner. Injections of curare into the dorsal lymph sacs or intraocularly into the vitreous of the eye produced similar results. Intraocular injections of Ringer solution of varying quantities of 0.9% NaCl (the carrier solution of the commercially prepared curare), had no adverse effect on the shedding response. Additionally, injections of curare into one eye had no effect on the rod shedding rate of the other eye.

Animals↗

Nutrition support affects the distribution and organ uptake of cachectin/tumor necrosis factor in rats.

BACKGROUND: We have previously observed a potentiation of the metabolic response to cachectin/tumor necrosis factor (TNF) by total parenteral nutrition (TPN) but not in anorexic orally fed animals. We hypothesized that nutritional status might affect TNF clearance kinetics. METHODS: We compared the clearance of a bolus of labeled TNF in TPN-fed animals given sufficient nutrients to grow called weight-gaining rats (WGR) with those given 50% of the WGR called weight-losing rats (WLR) and with orally fed rats (OFR). Data were analyzed using a two-compartment open system model and by linear systems analysis. RESULTS: The data from both types of analysis indicator that although metabolic clearance was similar, WGR had a slower fractional TNF clearance rate (FCR) as well as a larger volume of distribution than WLR or OFR. Further analysis showed that an increased proportion of the total mass of TNF resided in a plasma-associated compartment in WGR compared with WLR and OFR. In addition, WGR had reduced uptake of labeled TNF by the kidney. CONCLUSION: The data suggest that nutrition support influences either the distribution of TNF or the FCR, resulting in a greater retention in the plasma-associated compartment with intact absolute removal rates. This study has important implications concerning the type of nutrition support provided to the critically ill patient because our data suggest that clinical states with increased circulating TNF levels may be adversely affected by currently available nutritional practices.

Albumins↗