BACKGROUND: Impaired liver regeneration is a feature of alcoholic hepatitis, but the relative importance of alcohol, nutritional imbalance and inflammatory mediators in causing this effect is unclear. Non-alcoholic steatohepatitis (NASH) is a form of liver disease with similar morphology to alcoholic hepatitis, but the effect of this disorder on liver regeneration is unclear. We, therefore, examined the status of liver regeneration in a rat nutritional model of hepatic steatosis with inflammation, which is morphologically identical to NASH in humans. Methods: Male Wistar rats received a methionine-choline-deficient diet (MCDD) for 4 weeks before experiments and both isocaloric pair-fed and ad libitum-fed rats were used as controls. Following partial hepatectomy (68%), the extent of hepatic regeneration was determined 24 h later using [3H]-thymidine incorporation and restitution of liver mass. Results: There was no significant difference of [3H]-thymidine incorporation in MCDD-fed, pair-fed and ad libitum-fed rats (80+/-27, 78+/-11 and 80+/-6.3 d.p.m./microg DNA, respectively). Similarly, restituted liver masses in three groups of rats were not significantly different (17+/-3.8, 18+/-1.8 and 17+/-3.1% initial liver weight, respectively). Conclusions: The similarities in hepatic histology and cytochrome P450 2E1 induction between this nutritional model of hepatic steatohepatitis and alcoholic steatohepatitis imply that these two disorders share pathogenetic mechanisms. However, liver regeneration is not altered by NASH in rats, indicating that the nutritional and inflammatory changes that appear similar to those of alcoholic liver disease do not cause impairment of liver regeneration. 相似文献
We previously discovered a splice variant of choline acetyltransferase (ChAT) mRNA, and designated the variant protein pChAT because of its preferential expression in peripheral neuronal structures. In this study, we examined the immunohistochemical localization of pChAT in rat cochlea and compared the distribution pattern to those of common ChAT (cChAT) and acetylcholinesterase. Some neuronal cell bodies and fibers in the spiral ganglia showed immunoreactivity for pChAT, predominantly the small spiral ganglion cells, indicating outer hair cell type II neurons. In contrast, cChAT- and acetylcholinesterase-positive structures were localized to fibers and not apparent in ganglion cells. After ablation of the cochlear nuclei, many pChAT-positive cochlear nerve fibers became clearly visible, whereas fibers immunopositive for cChAT and acetylcholine esterase disappeared. These results suggested that pChAT and cChAT are localized in different systems of the rat cochlea; pChAT in the afferent and cChAT in the efferent structures. 相似文献
Cardiac reflexes originating from sensory receptors in the heart ensure blood supply to vital tissues and organs in the face of constantly changing demands. Atrial volume receptors are mechanically sensitive vagal afferents which relay to the medulla and hypothalamus, affecting vasopressin release and renal sympathetic activity. To date, two anatomically distinct sensory endings have been identified which may subserve cardiac mechanosensation: end-nets and flower-spray endings. To map the distribution of atrial receptors in the subendocardial space, we have double-labelled rat right atrial whole mounts for neurofilament heavy chain (NFH) and synaptic vesicle protein 2 (SV2) and generated high-resolution maps of the rat subendocardial neural plexus at the cavo-atrial region. In order to elucidate the nature of these fibres, double labelling with synaptophysin (SYN) and either NFH, calcitonin gene-related peptide (CGRP), choline acetyltransferase (ChAT) or tyrosine hydroxylase (TH) was performed. The findings show that subendocardial nerve nets are denser at the superior cavo-atrial junction than the mid-atrial region. Adluminal plexuses had the finest diameters and stained positively for synaptic vesicles (SV2 and SYN), CGRP and TH. These plexuses may represent sympathetic post-ganglionic fibres and/or sensory afferents. The latter are candidate substrates for type B volume receptors which are excited by stretch during atrial filling. Deeper nerve fibres appeared coarser and may be cholinergic (positive staining for ChAT). Flower-spray endings were never observed using immunohistochemistry but were delineated clearly with the intravital stain methylene blue. We suggest that differing nerve fibre structures form the basis by which atrial deformation and hence atrial filling is reflected to the brain. 相似文献
Acetylcholine may be released from gallbladder intrinsic nerves in response to cholecystokinin stimulation. This study characterized metabolites of [14C]choline produced in the gallbladder and released during incubation, with or without cholecystokinin-octapeptide. Radiolabeled [14C]choline was applied to the mucosal or muscle surface of intact guinea pig gallbladders in an organ bath. After radiolabeling, gallbladders were incubated with or without the contractile agonist cholecystokinin-octapeptide. Metabolites of [14C]choline were identified in gallbladder tissue and incubation buffers using HPLC and thin-layer chromatography. The major metabolites of [14C]choline were betaine and phosphocholine. [14C]Phosphocholine was incorporated slowly into [14C]phosphatidylcholine. [14C]Choline was released into buffers during incubation. [14C]Acetylcholine constituted less than 1% of radiolabel in the gallbladder. There was no identifiable [14C]acetylcholine released in buffers. Cholecystokinin-octapeptide did not affect choline metabolism. These studies showed that choline in the gallbladder is metabolized along pathways similar to those in the liver. Gallbladders released mostly choline, rather than acetylcholine, even during hormonally induced contraction.This project was supported by the Research and Development Office of the Department of Veterans Affairs. 相似文献
The ability of normal young pig aortic tissue to synthesize phospholipids from [2-14C]ethanolamine and [1,2-14C]choline, in vitro, has been examined in areas of focal Evans Blue accumulation (blue areas) and adjacent areas of no dye accumulation (white areas).
Incorporation of [2-14C]ethanolamine into total lipid was linear for 3 h of incubation in both blue and white areas. At 3 h, ethanolamine incorporation into phosphatidyl ethanolamine was significantly less in blue than in white areas.
[1,2-14C]Choline incorporation into total lipid was linear for 3 h of incubation in blue areas but not in white areas. At 30 min, choline incorporation into phosphatidyl choline was significantly less in blue than in white areas; at 1 h choline incorporation into phosphatidyl choline was similar in blue and white areas, while after 3 h of incubation incorporation was significantly greater in blue than in white areas.
With both [2-14C]ethanolamine and [1,2-14C]choline, the percentage distribution of label among individual phospholipids was similar in blue and white areas.
Phospholipid content of blue and white areas was similar.
The results presented demonstrate further focal metabolic differences within the same geographical region of the normal young pig aorta. 相似文献
Intestinal microbiota is a “dynamic organ” influencing host metabolism, nutrition, physiology and immune system. Among its several interactions, the role of a phosphatidylcholine metabolite derived by gut flora activity, i.e., trimethylamine-N-oxide (TMAO), allows perceiving a novel insight in the cardiovascular risk scenario, being a strong predictor of this condition. Based on current reports, including the paper of Tang et al., we describe here: the possible role of intestinal microbiota in cardiovascular risk as well as potential interventions to reduce gut flora TMAO production by diet, probiotics and antibiotics. Finally, we highlight the possibility of evaluating, monitoring and modulating TMAO in order to use its serum levels as a marker of cardiovascular risk in the next future, when the need of controlled studies on large series will be satisfied. 相似文献
LicC has been identified as a virulence factor of Streptococcus pneumoniae. However, its role in virulence is still not fully understood because deletion of licC is lethal for the bacterium. In this study, a mutant with 78-bp truncation at the C-terminus of licC was obtained from a signature-tagged mutagenesis (STM) library. The mutant was viable with a large reduction in enzymatic activity as CTP:phosphocholine cytidylyltransferase detected in vitro using a firefly luciferase assay. The mutation attenuated the adhesion and invasion of S. pneumoniae ST556 (serotype 19F) to epithelial cells by 72% and 80%, respectively, and increased the phagocytosis by macrophages for 16.5%, compared to the parental strain. When the mutation was introduced into the encapsulated D39 strain (serotype 2), it led to attenuated virulence in mouse models either by intranasal colonization or by intraperitoneal infection. In addition, the phosphocholine (PCho) on cell surface was decreased, and the choline binding proteins (CBPs) were impaired, which may explain the attenuated virulence of the mutant. These observations indicate that C-terminus of licC is accounted for the main activity of LicC in PCho metabolism and is essential for the virulence of S. pneumoniae, which provides a novel target for drug design against pneumococcal infection. 相似文献
Neuroinflammatory mechanisms contribute to the brain pathology resulting from human immunodeficiency virus (HIV) infection. Magnetic resonance spectroscopy (MRS) has been touted as a suitable method for discriminating in vivo markers of neuroinflammation. The present MRS study was conducted in four groups: alcohol dependent (A, n = 37), HIV‐infected (H, n = 33), alcohol dependent + HIV infected (HA, n = 38) and healthy control (C, n = 62) individuals to determine whether metabolites would change in a pattern reflecting neuroinflammation. Significant four‐group comparisons were evident only for striatal choline‐containing compounds (Cho) and myo‐inositol (mI), which follow‐up analysis demonstrated were due to higher levels in HA compared with C individuals. To explore the potential relevance of elevated Cho and mI, correlations between blood markers, medication status and alcohol consumption were evaluated in H + HA subjects. Having an acquired immune deficiency syndrome (AIDS)‐defining event or hepatitis C was associated with higher Cho; lower Cho levels, however, were associated with low thiamine levels and with highly active antiretroviral HIV treatment (HAART). Higher levels of mI were related to greater lifetime alcohol consumed, whereas HAART was associated with lower mI levels. The current results suggest that competing mechanisms can influence in vivo Cho and mI levels, and that elevations in these metabolites cannot necessarily be interpreted as reflecting a single underlying mechanism, including neuroinflammation. 相似文献