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M D Peck

Publications and source records attributed to M D Peck.

42 records · Page 3Linked to original sources
PubMedDate not supplied

Interaction of protein and zinc malnutrition with the murine response to infection.

Malnutrition increases the host's susceptibility to infection. However, the mechanisms are not well understood. This study examined the interaction of protein and zinc underfeeding in mice before challenge with an intracellular pathogen, Salmonella typhimurium. C3H/HeN mice (n = 68) were weighted and placed on one of four diets: 20% ovalbumin with adequate zinc (20% NL), 20% ovalbumin without zinc (20% LO), 1% ovalbumin with zinc (1% NL), and 1% ovalbumin without zinc (1% LO). At the end of 6 weeks they were again weighed and then challenged with 10(4) S. typhimurium intraperitoneally. Mortality was recorded over the next 2 weeks. Although weight loss was markedly affected by protein malnutrition (two-way analysis of variance: p = .0001), there was no independent effect by zinc (p = .3459). Similarly, protein malnutrition alone affected mortality rates (chi 2: p = .0001), whereas zinc had no independent effect (p = .7166). However, both protein and zinc underfeeding shortened the length of survival (Mann-Whitney U test: p less than .001). We conclude that protein malnutrition is the dominant factor influencing weight loss and mortality in this model. However, zinc malnutrition does shorten the length of survival and may contribute to the global immunosuppression noted in malnourished subjects.

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PubMedDate not supplied

Short-term dietary lipid manipulation does not affect survival in two models of murine sepsis.

Dietary lipid manipulation has been shown to have various effects on the immune system, depending on the amount of fat, degree of saturation, and type of fat used. In this study we investigated the role of different sources of fat at different levels on the survival of mice in two models of peritonitis, one with Pseudomonas aeruginosa and the other with Salmonella typhimurium. CF1 mice were pair-fed diets with 5% or 40% of total calories as fat. The source of fat used was coconut oil, oleic acid, safflower oil, or fish oil. Three other diets were tested as well, one with no fat, one with only 0.5% of total calories linoleic acid as the only source of fat, and a control diet that had 12% of total calories as corn oil. At the end of 2 weeks of feeding the experimental diets, mice were challenged with Ps aeruginosa intraperitoneally and mortality was recorded over 1 week. After 3 weeks of feeding the experimental diets, mice were challenged with S typhimurium and mortality was recorded over 2 weeks. No significant differences were seen on survival among groups fed different levels of fat, as well as different sources of fat. We conclude that, overall, 2- and 3-week manipulation of dietary fat does not affect outcome from infection in these models.

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PubMedDate not supplied

The role of protein and calorie restriction in outcome from Salmonella infection in mice.

We studied the separate effects of protein and calorie restriction in mice challenged with Salmonella typhimurium, an intracellular pathogen eliminated by cell-mediated immunity. Female A/J mice (n = 73) were placed on one of eight solid diets for 3 weeks. Animals were weighed at the beginning and the end of the feeding period. Diets were adjusted by two factors. The total amount of protein in the diet was 1%, 5%, 20%, or 40% by weight. The diets were fed to half the mice in quantities of 3 g and to the other half at 1.5 g per mouse per day. At the end of 3 weeks, mice were injected intraperitoneally with bacteria and mortality was observed for 2 weeks. Mortality was related to protein intake and was significantly higher in the 1% and 5% groups (chi 2: p = .0021). However, mortality was lower in the calorie-restricted groups (chi 2: p = .0242). Although caloric intake did not affect cell-mediated immunity, the response to 2,4-dinitrofluorobenzene was greater in the low protein groups. Lymphoproliferative responses in the mixed lymphocyte response were not affected by either caloric or protein intake. Lymphoproliferative responses to both lipopolysaccharide and phytohemagglutinin were affected by dietary protein but not by caloric intake; proliferative responses were higher in the low-protein groups. We conclude that protein restriction can increase mortality in this model. On the other hand, short-term calorie restriction can improve survival.

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PubMedDate not supplied

Does early excision of burn wounds change the pattern of mortality?

Ninety-five patients died at the University of Washington Burn Center from 1980 to 1985. Fifty-seven patients (60%) survived more than 3 days. Thirty-five of these patients underwent excision and grafting. The major causes of death were pneumonia, burn wound sepsis, and sepsis from multiple sources. Thus infection was the cause of death in 26 (74%) of these 35 patients. The other 22 patients who survived longer than 3 days did not undergo excision and grafting before death. The primary cause of death was pneumonia. Infection was the cause of death in 12 patients of this group (55%) and thus was the major cause of death in 62% of all patients who survived more than 3 days. Although early wound closure may affect overall mortality, it does not appear to materially change the pattern of the causes of death in those that die after 3 days of hospitalization.

Adult↗
PubMedDate not supplied

Diets high in polyunsaturated oils decrease lymphocyte membrane anisotropy and B-cell mitogenesis.

Balb/c mice were fed semipurified diets containing 40% of total calories as lipids: olive, safflower, or fish oil. After 2 weeks of feeding, splenic mononuclear cells were isolated and assayed for steady-state fluorescence anisotropy by means of the probe diphenylhexatriene. Splenocytes were also incubated with the mitogens concanavalin A, phytohemagglutinin, or lipopolysaccharide; subsequent uptake of tritiated thymidine was measured as an index of proliferation. No differences were observed in the membrane anisotropy and mitogenesis of mice fed the olive oil diet (high in monounsaturated fatty acids) and the control group. However, membrane anisotropy was significantly lowered in mice fed the safflower or fish oil diets (high in polyunsaturated fatty acids), and the mitogenic response to lipopolysaccharide was suppressed. Mitogenic responses to concanavalin A and phytohemagglutinin were not significantly affected by the type of lipid in the diet.

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