Acute choline deficiency in albino rats: vascular contractility, vascular fragility, and blood pressure.
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Shao-Yin-Ren Shi-Quang-Da-Bu-Tang (SDT) has been used traditionally to improve the systemic blood circulation and biological energy production in the body. The object of this study is to determine the effect of SDT extract on the decline of cerebral adenosine triphosphate (ATP) and choline content associated with learning and memory impairments in senescence-accelerated mice prone 8 (SAM P8). Twenty-four-week old mice were orally treated with SDT at 400 mg/kg body weight per day, and continued for 12 consecutive weeks. At the termination of the treatment, the body weight of SAM P8 was markedly lower than that of the equal aged senescence-resistant prone 1 (SAM R1), but this was conspicuously recovered to the level of SAM R1 by SDT treatment. SDT also significantly reduced the decline of cerebral weight (P < 0.05). By comparison with normal mice, a spontaneous decrease of cerebral ATP was observed in the SAM P8. Two- and 6-fold increases of cerebral ATP content were found in SAM R1 and SAM P8 by SDT administration, respectively. The cerebral choline content was significantly different between SAM R1 and SAM P8 aged 36-week old (P < 0.01). SDT remarkably restored the decrease of cerebral choline content in SAM P8 (P < 0.01). Taken together, these results demonstrate that SDT can reduce the decrease of cerebral weight, and restore the decline of cerebral ATP and choline content associated with an alteration of neuronal metabolism in SAM P8 brain. This suggests that pharmacological properties of SDT may participate in improvement of declined cerebral energy production and cholinergic neurotransmitter synthesis in senile dementia.
A choline uptake system accumulating free choline in an energy-dependent process is described in Mycoplasma fermentans. The uptake system has a K(m) of 2.2x10(-5) M and a V(max) of 0.15 nmol 10 min(-1) mg(-1) cell protein and the choline incorporated could be recovered in the soluble fraction as free choline, phosphorylcholine and CDP-choline. Choline accumulation by M. fermentans resulted in a marked choline depletion of the growth medium. The choline depletion of an astrocyte cell culture induced by M. fermentans was associated with the apoptotic death of the cells. Apoptosis was not obtained with heat-inactivated mycoplasmas and could be reversed by the addition of free choline to the growth medium.
BACKGROUND/AIMS: Liver regeneration following chronic injury is associated with inflammation, the proliferation of liver progenitor (oval) cells and fibrosis. Previous studies identified interferon-gamma as a key mediator of oval cell proliferation. Interferon-gamma is known to regulate Th1 cell activities during immune challenge. Therefore, we hypothesised that progenitor cell-mediated regeneration is associated with a Th1 immune response. METHODS: C57Bl/6 (normal Th1 response) and BALB/c mice (deficient in Th1 signalling) were placed on a carcinogenic diet to induce liver injury, progenitor cell proliferation and fibrosis. RESULTS: Serum transaminases and mortality were elevated in BALB/c mice fed the diet. Proliferation of liver progenitor cells was significantly attenuated in BALB/c animals. The pattern of cytokine expression and inflammation differed between strains. Liver fibrosis and hepatic stellate cell activation were significantly inhibited in BALB/c mice compared to C57Bl/6. In addition, interferon-gamma knockout mice also showed reduced fibrosis compared to wild type. These findings are in contrast to published results, in which interferon-gamma is shown to be anti-fibrogenic. CONCLUSIONS: Our data demonstrate that the hepatic progenitor cell response to a CDE diet is inhibited in mice lacking Th1 immune signalling and further show that this inhibition is associated with reduced liver fibrosis.
The wide range of lesions obtained after feeding weanling rats with hypolipotropic diets underlies the interest of this model in the study of the pathophysiology of acute renal failure. Renal functional studies (experiment A) show that the more advanced grade of morphological alteration correlates well with a progressively more severe deterioration in renal function. In animals wtih morphological evidence of repair there was an evident rise in the urinary volume of a low osmolality and a reduction in blood urea. In experiment B, where the sequential changes in urine volume and composition were analyzed, the installation of the disease is marked by a decrease in body weight, food intake and water intake, a rise in urine Na concentration and by a fall in urine flow rate and renal capacity to excrete concentrated urine. The progressive decline in renal function observed in these animals would seem more linked to a primary tubular alteration which gradually becomes more extensive than with an initial ischemic alteration. The tubular necrosis can be interpreted as the initial lesion common to the wide morphological range observed in this model (tubular necrosis of various grades, cortical necrosis or evidence of repair).
Gene expression profiles of HCC and surrounding non-cancerous tissues in rats fed a CDAA diet for 70 weeks, as well as normal liver tissues, were explored using an oligonucleotide microarray for 3757 genes. A total of 146 genes were identified as differentially expressed; the affected functions including metabolism, apoptosis, cell cycling, RNA splicing, Wnt signaling, reactive oxygen species-induced stress, and fibro/cirrhogenesis. The genes were found to fit into four distinct expression patterns after classification by hierarchical and k-means clustering procedures. Notably, genes within the same functional category tended to be found within the same cluster, thus gene functions appeared to be related to their expression patterns. For example, genes encoding receptors (Fisher's exact test, P < 0.01) and cytokines (Fisher's exact test, P < 0.05) were both enriched in a cluster characterized by low expression in HCC compared to their surrounding tissues. While some of the receptors in this cluster had cell-proliferative potential, others are known to be growth-suppressive. It was noted, however, that four of the 10 receptor genes encode G-protein-coupled receptors, for which growth-suppressive potential has been reported. The seven growth factors in the same cluster included two fibroblast growth factors. The current findings suggest the possibility that genes differentially expressed in this multistep carcinogenic model may be classified into relatively few clusters according to their expression patterns, and that these clusters may be associated with gene functional categories.
Thus, the pathologic consequences of feeding a CD diet are fatty liver, liver cell death, liver cell proliferation, and liver cell cancer. The fatty liver with CD is similar to that with other types of fatty liver in that the most attractive current hypothesis is based on some interference with the production and output of VLDL by the liver. The induction of cell death appears to be consistent with quite a different hypothesis, genesis and/or increase in liver free radicals leading to both acute necrosis and initiation of carcinogenesis. Especially noteworthy is the low incidence of liver cirrhosis, even after 2 years of exposure to the CD diet. The feeding of the CD diet reproducibly induces severe and persistent fatty liver coupled with extensive cell death, a combination that is frequently considered to be appropriate for the induction of "micronodular" (fatty) cirrhosis in humans. The findings with the LD diet, the high incidence of cirrhosis, with severe persistent fatty liver without significant cell death, together with the low incidence of cirrhosis with the CD diet, stand out as unpredictable and strange, according to current concepts of the pathogenesis of human cirrhosis. The CD model offers an unusual opportunity to explore in increasing detail the possible roles of free radicals in two important problems in pathology and medicine-acute cell injury and neoplasia. The challenges include mechanistic studies on how the free radicals are generated and how they relate to the biological consequences. The relatively slow sequential changes in the induction of cell injury and neoplasia makes the CD model one of the best for mechanistic studies relating to free radicals.
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The B6C3F1 strain of mice is prone to develop liver nodules as animals grow older. This spontaneous tumor development is enhanced by dietary lipotrope deficiency. The present studies were performed to evaluate the liver of the B6C3F1 mice in early periods of lipotrope deficiency and before the nodules appear. Mice were fed high levels of dietary fat (cotton seed oil or beef fat) without choline or vitamin B12. The livers of these mice were compared with those of mice subjected to partial hepatectomy or dietary phenobarbital both of which enhance liver nodule formation. The ability of putative preneoplastic hepatocytes to exclude parenteral-administered iron was used to detect this eventual phenotype. A lipotrope-deficient condition was established which typically exhibited fatty liver and increased cell proliferation, the latter measured by autoradiography. In the time periods evaluated the lipotrope-devoid diets were not sufficient to induce nodular or putative preneoplastic lesions. An excessively high activity of p-nitroanisole-O-demethylase and a single small fatty nodule were obtained when phenobarbital was added to the lipotrope-deficient diet. Scattered eosinophilic hepatocytes were seen in every experimental group when the histologic slides were stained for iron pigments, but their biologic significance in the present experiments could not be established. Under the conditions of this study, the liver of the B6C3F1 strain of mouse exhibited only minor indications of future tumor development.
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