Publications by authors named "Timbrell J"

Background: Little is known about the teaching and learning implications of instructional storytelling (IST) in nursing education or its potential connection to nursing theory.

Method: The literature establishes storytelling as a powerful teaching-learning method in the educational, business, humanities, and health sectors, but little exploration exists that is specific to nursing.

Results: An example of a story demonstrating application of the domains of Tanner's clinical judgment model links storytelling with learning outcomes appropriate for the novice nursing student.

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The aim of this study was to investigate the effect of individual sulfur amino acid deprivation in cadmium chloride toxicity. HTC cells were deprived of cystine and/or methionine for 12h and then exposed to CdCl(2) for 12h. HepG2 cells were deprived of cystine for 3 and 5h and exposed to CdCl(2) for 3h.

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Cadmium is a toxic metal and no effective antidote exists at present. The aim of this study was to examine whether sulphur amino acids, involved in glutathione synthesis, can modulate cadmium toxicity in vitro. Two hepatoma cell lines (HepG2 and HTC cells) were exposed to cadmium chloride (0-100 microM) for 8h in control media or in media containing 1mM of homocysteine, cysteine or cystathionine.

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Cadmium coexists with other metals in various products. Releases of cadmium in the environment occur in parallel to the release of other metals including copper, iron and zinc which also have an essential role in human homeostasis as they participate in various biochemical pathways. We studied the interaction of iron, copper, zinc and calcium channel blockers (nifedipine and verapamil) with cadmium chloride in two hepatoma cell lines (HepG2 and HTC cells) in order to determine if these trace elements can affect CdCl(2) uptake and interfere with its toxicity.

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The cytotoxicity of extracts from a widely used species of plant, Moringa stenopetala, was assessed in HEPG2 cells, by measuring the leakage of lactate dehydrogenase (LDH) and cell viability. The functional integrity of extract-exposed cells was determined by measuring intracellular levels of ATP and glutathione (GSH). The ethanol extracts of leaves and seeds increased significantly (p < 0.

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The aim of this study was to compare four in vitro cytotoxicity assays and determine their ability to detect early cytotoxic events. Two hepatoma cell lines, namely HTC and HepG2 cells, were exposed to cadmium chloride (0-300 microM) for 3, 5 and 8 h. Following exposure to the toxic metal cytotoxicity was determined with the lactate dehydrogenase leakage assay (LDH), a protein assay, the neutral red assay and the methyl tetrazolium (MTT) assay.

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Cadmium is a toxic metal and no uniform mechanism of toxicity has so far been proposed. The aim of this study was to investigate the biochemical effects of cadmium chloride in a rat hepatoma cell line (HTC cells) and the cellular events mediating DNA damage. HTC cells were exposed to various concentrations of cadmium chloride for 5 and 8 h and lysosomal damage was assessed with the neutral red assay (NR) and fluorescence microscopy.

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Methionine dependence has been reported in tumour cells and suggested as a possible target for chemotherapeutic drugs. The underlying defect has not been extensively researched, nor have levels of sulphur amino acids been examined in these cells. This study compared two rat liver tumour cell lines.

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Urinary creatine has been shown to markedly increase in rats following testicular damage caused by toxicants as diverse as cadmium, 2-methoxyethanol, 1,3-dinitrobenzene, and 2,3,5,6-tetramethylphenylene diamine. More recent findings have shown that urinary creatine is raised in mice exposed to 2-methoxyacetic acid. The most recent studies have revealed that urinary creatine and creatine in interstitial fluid in the testis are raised as early as four hours after dosing with 2-methoxyethanol.

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Alcohol was administered chronically to female Sprague-Dawley rats in a nutritionally adequate totally liquid diet for 28 days. This resulted in significant hepatic steatosis and lipid peroxidation. Beta-alanine, when co-administered with alcohol, seemed to increase hepatic steatosis, as assessed histologically, but decreased triglyceride levels as measured biochemically.

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Stress protein induction has been advocated as a sensitive indicator of compound-induced toxicity. In monolayer cultures of primary hepatocytes, however, the two stress proteins, Hsp25 and Hsp72/3 are up-regulated, probably due to the effect of the isolation procedure and adaptation of the cells to the culture conditions. The aim of the current studies was to determine whether liver spheroids would provide an improved experimental model for the study of heat shock protein induction in vitro.

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Alcohol (ethanol) was administered chronically to female Sprague-Dawley rats in a nutritionally adequate, totally liquid diet for 28 days. This resulted in significant hepatic steatosis and lipid peroxidation. When taurine was administered for 2 days following alcohol withdrawal it was found to reduce alcohol-induced lipid peroxidation and completely reversed hepatic steatosis.

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Changes in urinary levels of taurine have been reported in rats following treatment with various xenobiotics including those which alter protein synthesis and/or are hepatotoxic. This paper reports on the time course of the urinary elevation of taurine following treatment of rats with tetracycline (50, 150 and 200 mg.kg-1).

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Alcohol was administered chronically to female Sprague Dawley rats in a nutritionally adequate totally liquid diet for 28 days. This resulted in hepatic steatosis and lipid peroxidation. Taurine, when co-administered with alcohol, reduced the hepatic steatosis and completely prevented lipid peroxidation.

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The administration of a single subcutaneous dose of clenbuterol to rats altered the level of taurine in certain tissues. Taurine levels in cardiac tissue were significantly decreased 3 h after the administration of 250 micrograms/kg of clenbuterol and remained significantly depressed at 12 h post-dose only returning to control values by 24 h. The level of taurine in the liver increased 3 h after clenbuterol administration but was lower than the control value at 24 h post dose.

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The hepato-steatogenic compound ethionine has been used to investigate the correlations between in vivo and in vitro toxicity data. The aim was to find a suitable model of toxicity in hepatocyte suspensions or monolayers in vitro, which could predict the known toxicity of ethionine in vivo and which could be implemented in screening compounds of unknown toxicity. Thus a variety of markers of cytotoxicity, metabolic competence and liver-specific functions were investigated in rat hepatocyte suspensions and monolayers and compared with in vivo data in the rat.

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The use of biomarkers in toxicology is becoming increasingly important. This article briefly reviews some of the aspects in an attempt to give an overall view of the field. Some of the new developments, particularly in relation to biomarkers of exposure and response, are mentioned.

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The Sertoli cells have been identified as the primary locus for creatine synthesis within the seminiferous epithelium. The purpose of the studies reported here was to examine the effect of modulators of Sertoli cell function on creatine secretion by primary cultures of these cells. Sertoli cell-enriched cultures, maintained in a defined medium, secreted creatine into the incubation medium in a manner that was linear with time over at least 6 h, but which had reached a plateau within 24 h.

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The testis synthesizes creatine from both arginine and glycine precursors, but when rat testicular tissue is separated into seminiferous tubules and interstitial cells, creatine synthesis occurs only in the tubular fraction. The purpose of the work presented here was to define the locus of creatine synthesis within the seminiferous tubules, by using cell separation and culture techniques to examine synthesis in the Sertoli cells and germ cells. The total creatine content, in the cellular compartment and incubation medium, of Sertoli-germ cell co-cultures and of Sertoli cell-enriched cultures, largely free of germ cells, increased by similar amounts over a 24 h incubation period.

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Treatment of animals with hydrazine causes the accumulation of triglycerides in the liver but the mechanism remains unclear. Therefore, the effect of hydrazine on hepatic triglyceride synthesis and subsequent transport was studied in a hepatocyte model, in vitro in order to isolate liver cells from extrahepatic influences. Hepatocytes were isolated and either incubated in suspension with [14C]palmitate in the presence of hydrazine (2-12 mM) or pre-incubated with [14C]palmitate, washed free of the fatty acid and then incubated with hydrazine (2-12 mM).

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Methylene dianiline (DAPM) causes hepatic damage and bile duct necrosis in rats. This has been detected histologically and biochemically. The toxicity was dose related over the range 0-100 mg/kg but the dose response relationship showed a maximum at about 75-100 mg/kg.

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