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Biomedical subjects

J H Shaw

Publications and source records attributed to J H Shaw.

179 records · Page 10Linked to original sources
PubMedDate not supplied

Inability of low levels of sorbitol and mannitol to support caries activity in rats.

Under the environmental conditions of these experiments, neither 5 nor 10% sorbitol or mannitol in diets containing 62 or 57% corn starch, respectively, was capable of increasing the caries activity in rats above the level supported by a 67% starch diet. In contrast, 5% sucrose in the presence of 62% corn starch caused a slight increase and 10% sucrose in the presence of 57% starch caused a significant increase in caries activity beyond that observed when the diet containing 67% starch as the only carbohydrate was fed.

Animals↗
PubMedDate not supplied

Effect of alanine infusion on glucose and urea production in man.

We have tested the response to a primed constant infusion of alanine (2 mg/kg X min infusion, 120 mg/kg prime) on glucose and urea kinetics in overnight fasted volunteers by using primed-constant infusions of 6,6-d2-glucose and 15N2-urea. When no alanine was infused, plateaus in glucose and urea concentration and enrichment were maintained for the final 3 hr of a 4-hr infusion of tracers. When alanine was infused over the final 2 hr of a second protocol, urea enrichment decreased significantly, indicating an increase in urea production from 4.4 +/- 0.31 to 7.0 +/- 0.63 mumol/kg X min. This corresponded to a potential increase in gluconeogenesis from alanine of 20%. Nonetheless, the alanine infusion had no significant effect on either the plasma concentration or enrichment of glucose, which means that hepatic glucose output was not affected. We conclude, therefore, that increasing gluconeogenic precursor availability does not stimulate hepatic glucose output in overnight-fasted man.

Adult↗
PubMedDate not supplied

Protein-sparing effect of substrate infusion in surgical patients is governed by the clinical state, and not by the individual substrate infused.

We have determined iostopically the effect of either glucose or lipid infusion on rates of glucose turnover, glucose oxidation, and net protein catabolism (NPC) in three groups of surgical patients. Kinetic measurements were performed using the primed constant infusion of 3H-glucose, and either 14C-glucose or 14C-urea. The three groups included patients with: (1) sepsis and/or trauma (ST); (2) upper gastrointestinal cancer (UGI); (3) lower gastrointestinal cancer (LGI). In each patient group the effect of either glucose infusion (approximately 4 mg/kg.min) or lipid infusion (20% Intralipid lipid emulsion infused to provide calories approximately isocaloric to the glucose infusion) was assessed. The infusion of calories as either glucose or lipid was equally effective as a means of suppressing NPC in each individual patient group, and the degree of response was governed by the clinical disease state. In the LGI and ST patients the infusion of either glucose or fat resulted in a significant suppression of NPC (p less than 0.005) of approximately 15%. However, the ongoing rate of NPC that occurred despite substrate infusion was more than twice as great in the ST patients as in the LGI patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Relative importance of amino acid infusion as a means of sparing protein in surgical patients.

We performed isotopic infusions in 51 surgical patients to investigate the effectiveness of different substrates to conserve protein. All patients were initially studied in the basal state and then the effects of glucose infusion (GL, N = 13), lipid infusion (LIP, N = 11), or amino acid infusion (AA, N = 17) were determined. Ten patients receiving total parenteral nutrition (TPN) were also studied. The basal value for net protein catabolism (NPC) in GL patients was 1.53 +/- 0.4 (SEM) g/kg/day decreasing to 1.39 +/- 0.4 g/kg/day during glucose infusion (p less than 0.01). The basal NPC in the LIP group was 2.04 +/- 0.4 g/kg/day decreasing to 1.72 +/- 0.3 g/kg/day during lipid infusion (p less than 0.01). In the TPN patients the NPC was 0.79 +/- 0.46 g/kg/day whereas in the AA patients the basal value for NPC was 1.37 +/- 0.14 g/kg/day decreasing to -0.77 +/- 0.11 g/kg/day during amino acid infusion (p less than 0.0005). From our study we conclude that: (1) All substrates commonly used in intravenous feeding have the capacity to spare protein. (2) Protein sparing was more pronounced when a balanced amino acid infusion was used than with either glucose or lipid infusion alone. (3) This effect is not solely due to insulin secretion as larger insulin responses were seen with both GL and TPN patients. (4) These results may have implications for peripheral vein feeding with amino acid solutions where there is a contraindication for full TPN or the lack of resources for administering it.

Adult↗
PubMedDate not supplied

Total parenteral nutrition in surgical illness: how much? How good?

Using primed constant infusions of isotopes and indirect calorimetry, we assessed protein, glucose, and fat kinetics in severely ill surgical patients suffering from sepsis, major trauma, gastrointestinal cancer, or nutritional depletion from benign disease. We also assessed the effect of 5 days of total parenteral nutrition (TPN) on abnormal metabolism in these states. In the basal state, patients with sepsis, trauma, or cancer had an elevated rate of net protein catabolism due to an increased rate of whole-body protein catabolism, whereas whole-body protein synthesis was not impaired. TPN had no impact on the elevated rate of whole-body protein catabolism in these conditions but decreased the rate of net protein catabolism, suggesting that increased substrate availability optimizes whole-body protein synthesis. Consequently, few surgical patients became anabolic while receiving TPN. In contrast, patients with nutritional depletion from benign disease had a decreased rate of net protein loss compared with volunteers and could be made anabolic with the administration of TPN. All patients studied had an elevated rate of plasma glucose production, impaired glucose oxidation, and an increased rate of Cori cycling in the basal state. After 5 days of TPN, most surgical patients showed improved ability to oxidize glucose, but the high rates of glucose recycling to lactate persisted. Patients suffering from sepsis, trauma, or cancer had an enhanced rate of lipolysis in the basal state associated with an increased rate of whole body-fat oxidation compared with healthy volunteers. After administration of TPN, whole-body fat oxidation was significantly decreased in patients with trauma but increased in patients with sepsis or cancer.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Glucose↗
PubMedDate not supplied

Effects of repeated oral doses of demethylchlortetracycline on bones and dentin of young rhesus monkeys.

Seven oral doses of demethylchlortetracycline were administered to monkeys that received serial injections of lead acetate to intravitally stain calcification sites. Bone growth was greatly inhibited, whereas dentin apposition was spared from the cumulative toxicity of demethylchlortetracycline. Cessation of bone growth and its duration could be correlated with serum levels.

Administration, Oral↗