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Biomedical subjects

R S Pekarek

Publications and source records attributed to R S Pekarek.

9 recordsLinked to original sources
PubMed1979

Abnormal cellular immune responses during acquired zinc deficiency.

The cellular immune response of a 17-year-old decerebrate male with acquired zinc deficiency was studied. He had been fed a commercial formula which contained 7.6 mg zinc per kilogram. His caloric intake had been inadequate as judged by his cachexia. A detailed pretreatment nutritional assessment (five separate observations) which included total serum protein and globulins, albumin, folate, vitamins A, B2, C, ceruloplasmin, and plasma zinc, copper, iron, and total iron binding capacity revealed that the patient was deficient only in zinc and calories. His plasma zinc was 41 +/- 5 microgram/d1 compared with our laboratory norm of 89 +/- 9 microgram/d1 for young adult males. Cellular immunity was assessed by delayed skin reactivity to dinitrochlorobenzene and by in vitro lymphocyte transformation studies. Before zinc therapy the patient rendered a negative skin reaction to dinitrochlorobenzene, and the ability of his lymphocytes to undergo blast transformation in response to mitogen stimulation was significantly depressed with a stimulation index of 4.7 +/- 0.8 as compared with 139.1 +/- 77.3 for controls. Within 3 weeks after zinc therapy (22.7 mg zinc per day) he demonstrated a positive delayed skin reaction to dinitrochlorobenzene and a normal lymphocyte response stimulation index = 205.5 +/- 42.6 versus 199.3 +/- 58.2 for control). In addition, a pretreatment facial seborrhea and a decubitus ulcer rapidly healed.

Adolescent↗
PubMed1978

Leukocytic endogenous mediator in Crohn's disease.

Reduced concentrations of plasma zinc associated with elevated levels of serum leukocytic endogenous mediator activity were found in 17 patients hospitalized with acute exacerbation of Crohn's disease. Neither the decrease in plasma zinc nor the increase in leukocytic endogenous activator activity in nine outpatients with quiescent disease was significant. Leukocytic endogenous mediator activity may be increased in inflammatory conditions as well as in microbial infections. Although zinc deficiency may be common in patients with Crohn's disease, exclusive reliance on circulating zinc levels to assess zinc nutriture in active Crohn's disease may be misleading.

Adolescent↗
PubMed1976

Protein synthesis in zinc deficient rats during tularemia.

The effect of zinc deficiency on protein synthesis in rats during tularemia was studied. Five weeks prior to infection with the live vaccine strain of Francisella tularensis, rats had been assigned to one of three dietary groups: zinc deficient (-Zn), pair-fed (PF) or ad libitum (AL). Within 4 weeks, zinc deficiency manifested itself by diminished growth rate, decreased serum and liver zinc concentrations and alopecia. By 18 hour post infection, rats of all groups were febrile and exhibited an increased hepatic uptake of zinc. Despite initially lower concentrations of seromucoid in the PF and -Zn groups, infection elicited an increase in seromucoid concentration as well as enhanced incorporation of 3H-leucine into this fraction of comparable degree in all dietary groups. The same held true for ceruloplasmin. Alpha 2-macrofetoprotein also increased to the same extent in all dietary groups. Infection was associated with a decrease in extractable albumin in ad libitum and pair fed control groups. Only the -Zn group showed a significant decrease in specific activity suggestive of diminished albumin synthesis. Zinc deficiency of itself did not cause a decrement in radiolabel in muscle protein. Thus, despite documented zinc deficiency, rats subjected to the stress of infection respond by synthesizing increased amounts of acute phase globulins apparently at the expense of serum albumin and muscle protein synthesis.

Alopecia↗
PubMed1975

Induced metabolic sequelae of tularemia in the rat: correlation with tissue damage.

Serum and liver zinc concentration, amino acid uptake by liver, seromucoid content, and alpha2-macrofetoprotein production were measured in vaccinated as well as nonimmune rats exposed to either virulent (SCHU S4) or attenuated (LVS) strains of Francisella tularensi. It appears that liver damage (pyogranulomatous lesions) must occur before there is any alteration in the above variables. The presence of bacteria in the liver is not of itself sufficient to lead to the onset of systemic, induced metabolic sequelae (IMS). The occurrence of zinc redistribution in all instances of increased serum protein synthesis may imply a necessary relationship between these two sequelae. Amino acid redistribution does not appear to be linked to serum protein synthesis. An endogenous mediator of systemic IMS can be detected in tularemic rats by injection of the serum of these animals into healthy recipients. The occurrence of zinc redistribution and increased serum protein synthesis in some groups of rats in the absence of amino acids uptake by liver, as well as the apparent differential dose responsiveness of these responses, are suggestive of a multiplicity of endogenous mediators.

Amino Acids↗
PubMed1975

A protein from polymorphonuclear leukocytes (LEM) which affects the rate of hepatic amino acid transport and synthesis of acute-phase globulins.

A proteinaceous secretion from phagocytizing polymorphonuclear leukocytes, termed "leukocytic endogenous mediator" (LEM), has been shown to have marked effects on hepatic amino acid transport and RNA and protein synthesis. A single injection of LEM results in a marked accumulation of labeled nonmetabolizable model amino acids in the liver of normal rats. The LEM-stimulated uptake of amino acids by liver was observed in adrenalectomized, hypophysectomized, thyroidectomized, or diabetic rats and could not be duplicated by pharmacological doses of a large variety of hormones. In addition, LEM stimulated an increased uptake of alpha-aminoisobutyric acid by isolated livers during their perfusion in vitro. LEM also stimulated an increased incorporation of orotic acid into hepatic RNA of intact rats, especially into the bound ribosomal fraction. This increased synthesis of RNA preceded an enhanced hepatic production of a number of the acute-phase plasma globulins. LEM did not stimulate the adenylate cyclase-cAMP system in liver and was not found to utilize this system as a second messenger. Thus, the effects of LEM in stimulating hepatic amino acid transport appear to be direct, without mediation by other hormones, and to be independent of cAMP. On the other hand, the ability of LEM to stimulate RNA and acute phase globulin synthesis in liver may require the presence of physiological quantities of hormones such as adrenal corticoids.

Adenylyl Cyclases↗
PubMed1975

Relationship between serum chromium concentrations and glucose utilization in normal and infected subjects.

Studies in healthy individuals demonstrate that serum chromium concentrations fall precipitiously following the intravenous administration of a 30-gm. glucose load. Significant decreases from baseline control fasting serum Cr concentrations were also observed when intravenous glucose was given during sandfly fever. Glucose disappearance rates also decreased significantly to approximately one half of pre-illness control values while serum Cr values declined still further. In addition, serum Cr disappearance rates could be calculated. When individual preexposure and postexposure serum glucose and Cr disappearance rates were compared, significant linear correlation was found (P smaller than 0.05). Acute infection appears to reduce the availability of circulating Cr, which may contribute to the altered glucose metabolism characteristic of acute infections even in the presence of elevated insulin levels and other hormonal changes.

Acute Disease↗