J Food Prot
January 1991
Modified-atmosphere packaged (MAP) foods have become increasingly more common in North America, as food manufacturers have attempted to meet consumer demands for fresh, refrigerated foods with extended shelf life. Although much information exists in the general area of MAP technology, research on the microbiological safety of these foods is still lacking. The great vulnerability of MAP foods from a safety standpoint is that with many modified atmospheres containing moderate to high levels of carbon dioxide, the aerobic spoilage organisms which usually warn consumers of spoilage are inhibited, while the growth of pathogens may be allowed or even stimulated.
View Article and Find Full Text PDFThe effect of acute exposure to carbon monoxide on ventricular arrhythmias was studied in a previously described chronically maintained animal model of sudden cardiac death. In 60 percent of dogs with a healed anterior myocardial infarction, the combination of mild exercise and acute myocardial ischemia induces ventricular fibrillation. The events in this model are highly reproducible, thus allowing study by internal control analysis.
View Article and Find Full Text PDFOver the course of 4 hr, the metabolism of acetaminophen (APAP) by cultured rat hepatocytes resulted in a depletion of protein thiols and an accumulation of oxidized glutathione (GSSG) in the medium. With 20 mM APAP, arylation and the formation of glutathione mixed disulfides accounted for a loss of 22% of the total protein thiols in the absence of any loss of viability. With 20 mM APAP and an inhibition of glutathione reductase by 1.
View Article and Find Full Text PDFPrimary cultures of rat hepatocytes were used to explore the mechanisms of the toxicity of aryl halides. The sensitivity of the hepatocytes to chloro-, bromo-, and iodobenzene was enhanced by inhibition of glutathione reductase with 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU). In each case, the increased cell killing depended on the metabolism of the toxicant, a result shown by the protective effect of SKF-525A, an inhibitor of mixed function oxidation.
View Article and Find Full Text PDFJ Biol Chem
September 1990
In order to identify novel proteins produced by activated macrophages, a cDNA library was made from cultures of the mouse macrophage-like cell line RAW 264.7 that had been treated with conditioned medium from mitogen-stimulated spleen cells, and the library was screened by differential plaque hybridization. A cDNA clone was isolated that detected a 1.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
July 1990
In order to identify novel mediators synthesized in activated macrophages, a cDNA library was prepared from cultures of the mouse macrophage cell line RAW 264.7 that had been treated with lymphokine-rich conditioned medium from mitogen-stimulated mouse spleen cells. Differential plaque hybridization identified a cDNA, designated m119, that detected a 1.
View Article and Find Full Text PDFJ Appl Physiol (1985)
July 1990
To determine whether pathways from the rostral pons, capable of influencing breathing, were present in immature mammals, the excitatory amino acid glutamate (sodium salt) was pressure injected in very small volumes into the rostral pons of suckling and adult opossums. The youngest animals tested were approximately 3 wk old (1.5-2.
View Article and Find Full Text PDFLiposome-encapsulated (LSOD) or free (FSOD), human recombinant Cu-Zn superoxide dismutase prevented the killing of cultured rat hepatocytes by tert-butyl hydroperoxide (TBHP). A dose of 32 U/ml of LSOD reduced the cell killing by 50%. By contrast, it required 288 U/ml of FSOD to similarly reduce the toxicity of TBHP by 50%.
View Article and Find Full Text PDFAppl Environ Microbiol
June 1990
The effect of prior heat shock on the thermal resistance of Listeria monocytogenes in meat was investigated. A sausage mix inoculated with approximately 10(7) L. monocytogenes per g was initially subjected to a heat shock temperature of 48 degrees C before being heated at a final test temperature of 62 or 64 degrees C.
View Article and Find Full Text PDFLiposome-encapsulated human recombinant superoxide dismutase (LSOD) protected male rats that were pretreated with 3-methylcholanthrene from the liver necrosis produced by acetaminophen. By contrast, SOD-free liposomes, free SOD, or heat-denatured LSOD had no protective effect. Liposome-encapsulated SOD did not simply delay the onset of liver necrosis.
View Article and Find Full Text PDFPretreatment of cultured hepatocytes with the ferric iron chelator deferoxamine prevents the killing of the cells by tert-butyl hydroperoxide (TBHP). Incubation of the deferoxamine-pretreated hepatocytes in a serum-free medium containing only 0.25 nM iron restored the sensitivity of the cells to TBHP within 4 to 6 hr.
View Article and Find Full Text PDFCalcium ions have been increasingly implicated as a mediator of the mechanisms generating lethal cell injury under a variety of pathologic circumstances. An overview of the various roles suggested for such alterations in cellular calcium homeostasis is presented. The central role of plasma membrane damage in the genesis of irreversible cell injury is used to divide the postulated roles for calcium ions into two major mechanisms.
View Article and Find Full Text PDFEnvironmental factors are important mediators of many diseases of the digestive system, defined as the alimentary tract and the accessory organs of digestion, the liver and pancreas. In this review, we principally focus on the action of chemical agents which are classified as (1) naturally occurring compounds, (2) occupational hazards, (3) therapeutic drugs, and (4) constituents of substances of abuse. In addition, the putative role of dietary habits in the pathogenesis of malignant diseases of the digestive system is discussed.
View Article and Find Full Text PDFA method is described for classifying and quantifying surface tissue damage caused by self-injurious behavior. The Self-Injury Trauma Scale permits differentiation of self-injurious behavior according to topography, location of the injury on the body, type of injury, number of injuries, and estimate of severity. Fifty pairs of independently scored records were subjected to interrater reliability analyses, and the following mean (median) percentage agreement scores were obtained: overall agreement, 97% (98%); location of injury, 99% (100%); type of injury, 96% (100%); number of injuries, 89% (100%); and severity of injury, 94% (100%).
View Article and Find Full Text PDFCurettage and bone grafting has been the traditional treatment for unicameral bone cysts. Aspiration followed by injection of methylprednisolone acetate has been successfully used by Scaglietti et al. We reviewed 59 patients treated for unicameral bone cysts.
View Article and Find Full Text PDFWR-2721 is a thiophosphate analog of cysteamine that produces hypocalcemia in vivo. Previous studies suggest that WR-2721 produces hypocalcemia by independent inhibitory effects on parathyroid hormone (PTH) secretion, osteoclastic bone resorption, and tubular reabsorption of calcium. We sought to determine if WR-2721 would decrease bone loss in an animal model of disuse osteoporosis produced by unilateral knee tenotomy in the rat.
View Article and Find Full Text PDFBiochem Pharmacol
November 1989
The H2O2 generated by menadione kills cultured hepatocytes by a mechanism that depends in large part on a cellular source of ferric iron. Chelation of this iron by deferoxamine reduced by two-thirds the number of dead cells without any effect on the loss of 30% of total protein thiols, the formation of protein mixed disulfides, or the accumulation of oxidized glutathione (GSSG). The loss of protein thiols was accounted for by the formation of glutathione mixed disulfides from GSSG and the arylation of protein nucleophiles by menadione.
View Article and Find Full Text PDF1. We have examined whether the apparently ouabain-resistant fraction of cellular volume regulation in liver slices under isosmotic conditions is due to a failure of ouabain to cause complete inhibition of the coupled transport of Na+ and K+. The ion and water contents of rat and rabbit liver slices were altered by pre-incubation at 1 degree C and then allowed to recover at 38 degrees C, with or without ouabain or other inhibitors.
View Article and Find Full Text PDFBiochem Biophys Res Commun
August 1989
A study was made of the conditions of the killing of cultured hepatocytes by the reactive disulfide cystamine. Six to 12 mM cystamine killed up to 60% of the hepatocytes within 3 hours. The cytosolic calcium ion concentration rose prior to the loss of viability.
View Article and Find Full Text PDFOrientation programs that introduce employees to the company can promote the company product and organizational values to employees. United Hospital Inc. is a multi-health-care corporation that has experienced positive results from a new-employee orientation program.
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