Ethanol-related adaptive changes and physical dependence in rats after exposure to ethanol

Adaptive changes that occur after chronic exposure to ethanol are an important component in the development of physical dependence. We have focused our research on ethanol-induced changes in the expression of several genes that may be important in adaptation. In this article, we describe adaptive changes at the level of the N-methyl-D-aspartate receptor, in the protein expression and activity of the Egr transcription factors, and in the expression of a novel gene of unknown function. (C) 2001 Elsevier Science Inc. All rights reserved.

Irritative symptoms after colposuspension: Are they due to distortion or overelevation of the anterior vaginal wall and trigone?

Symptoms of bladder irritability are common after incontinence surgery but their cause is unknown. This study tests the hypothesis that irritative symptoms after colposuspension are due to distortion of the trigone. As part of longitudinal follow-up studies, 175 women were examined 6 months to 12 years after either an open or a laparoscopic Burch colposuspension. The main outcome measures were symptoms of bladder irritability (frequency, nocturia and urge incontinence) and ultrasound findings (bladder neck position at rest and on Valsalva, the presence of a colposuspension ridge, ridge depth and ridge distance, and trigonal angle). Two positive associations between ultrasound parameters and symptoms of bladder irritability were observed: urge incontinence was more likely in the presence of bladder neck funneling, and women with nocturia had a higher trigonal angle. Increased distortion of the trigone was associated with a reduced incidence of urge incontinence in the subgroup of patients after laparoscopic colposuspension. The data presented in this study do not support the hypothesis that symptoms of bladder irritability are due to trigonal distortion or overelevation.

The use of perineal ultrasound to quantify levator activity and teach pelvic floor muscle exercises

Perineal ultrasound was used to detect and quantify levator activity by measuring the displacement of the internal urethral meatus against the inferoposterior margin of the symphysis pubis, Women who had previously been instructed in pelvic floor muscle exercises were more likely to contract the levator muscle when asked to do so than were those without previous instruction (P

The urethral pressure profile and ultrasound imaging of the lower urinary tract

In a prospective study 105 patients with symptoms of stress incontinence underwent video-urodynamic testing, including resting urethral pressure profilometry and translabial ultrasound. The urethral pressure profile (UPP) included maximum urethral closure pressure (MUCP), functional length (FL) and area under the curve (AUC). Ultrasound parameters included urethral thickness, urethral rotation and bladder neck descent, as well as funneling/opening of the internal urethral meatus on Valsalva maneuver. Levator contraction strength was assessed measuring the cranioventral displacement of the internal meatus. Negative correlations between UPP data and age, parity and previous surgery were observed which were consistent with literature data. There was a positive correlation :between the urethral AP diameter on ultrasound and the MUCP, which agrees with reports showing reduced sphincter thickness or volume in stress-incontinent women. Hypermobility on ultrasound did not correlate with UPP data. However, a lower MUCP correlated with extensive opening of the bladder neck. Finally, there was a trend towards poorer pelvic floor function with lower MUCP measurements.

Cloning and gastrointestinal expression of rat hephaestin: relationship to other iron transport proteins

The membrane-bound ceruloplasmin homolog hephaestin plays a critical role in intestinal iron absorption. The aims of this study were to clone the rat hephaestin gene and to examine its expression in the gastrointestinal tract in relation to other genes encoding iron transport proteins. The rat hephaestin gene was isolated from intestinal mRNA and was found to encode a protein 96% identical to mouse hephaestin. Analysis by ribonuclease protection assay and Western blotting showed that hephaestin was expressed at high levels throughout the small intestine and colon. Immunofluorescence localized the hephaestin protein to the mature villus enterocytes with little or no expression in the crypts. Variations in iron status had a small but nonsignificant effect on hephaestin expression in the duodenum. The high sequence conservation between rat and mouse hephaestin is consistent with this protein playing a central role in intestinal iron absorption, although its precise function remains to be determined.

Molecular genetics of schizophrenia

1. Schizophrenia is a chronic, disabling brain disease that affects approxmately 1% of the world's population. It is characterized by delusions, hallucinations and formal thought disorder, together with a decline in socio-occupational functioning. While the causes for schizophrenia remain unknown, evidence from family, twin and adoption studies clearly demonstrates that it aggregates in families, with this clustering largely attributable to genetic rather than cultural or environmental factors. Identifying the genes involved, however, has proven to be a difficult task because schizophrenia is a complex trait characterized by an imprecise phenotype, the existence of phenocopies and the presence of low disease penetrance, 2. The current working hypothesis for schizophrenia causation is that multiple genes of small to moderate effect confer compounding risk through interactions with each other and with non-genetic risk factors, The same genes may be commonly involved in conferring risk across populations or they may vary in number and strength between different populations. To search for evidence of such genetic loci, both candidate gene and genome-wide linkage studies have been used in clinical cohorts collected from a variety of populations. Collectively, these works provide some evidence for the involvement of a number of specific genes (e.g. the 5-hydroxytryptamine (5-HT) type 2a receptor (5-HT2a) gene and the dopamine D-3 receptor gene) and as yet unidentified factors localized to specific chromosomal regions, including 6p, 6q, 8p, 13q and 22q, These data provide suggestive, but no conclusive, evidence for causative genes. 3. To enable further progress there is a need to: (i) collect fine-grained clinical datasets while searching the schizophrenia phenotype for subgroups or dimensions that may provide a more direct route to causative genes; and (ii) integrate recent refinements in molecular genetic technology, including modern composite marker maps, DNA expression assays and relevant animal models, while using the latest analytical techniques to extract maximum information in order to help distinguish a true result from a false-positive finding.

Spatial distribution and developmental appearance of postjunctional P2X(1) receptors on smooth muscle cells of the mouse vas deferens

P2X(1)-type purinoceptors, have been shown to mediate fast transmission between sympathetic varicosities and smooth muscle cells in the mouse vas deferens but the spatial organization of these receptors on the smooth muscle cells remains inconclusive. Voltage clamp techniques were used to estimate the amplitudes of spontaneous excitatory junction currents (SEJCs) in cells of the vas deferens longitudinal smooth muscle layer. These currents involved the activation of about 6% of the P2X-type channels present on the cell, as compared to whole cell currents produced when isolated smooth muscle cells were exposed to maximal concentrations of either ATP or alpha,beta -MeATP. Immunofluorescence staining of the vas deferens with antibodies against P2X(1) receptor showed a diffuse, grainy distribution over the entire membrane of each smooth muscle cell. Anti-P2X(1) staining was not markedly clustered beneath anti-SV2-stained sympathetic varicosities. Similar results were obtained for cells in the urinary bladder. During development, P2X(1) mRNA was detected as early as embryonic day 15 (E15). Increasing intensities of diffuse immunostaining for P2X(1) were observed in the walls of the bladder, tail artery, and aorta from E15 until 6 weeks postnatal. The vas deferens showed increasing intensities of diffuse staining of its smooth muscle layers between 2 and 6 weeks postnatal, consistent with the time-course of development of fast purinergic transmission described previously. Together, the results suggest that the response of smooth muscle of the vas deferens to ATP released from sympathetic varicosities relies on rapidly desensitizing P2X(1) receptors, distributed diffusely across the smooth muscle cell surface. Synapse 42:1-11, 2001. (C) 2001 Wiley-Liss, Inc.

Thiopalmitoylation of myelin proteolipid protein epitopes enhances immunogenicity and encephalitogenicity

Proteolipid protein (PLP) is the most abundant protein of CNS myelin, and is posttranslationally acylated by covalent attachment of long chain fatty acids to cysteine residues via a thioester linkage. Two of the acylation sites are within epitopes of PLP that are encephalitogenic in SJL/J mice (PLP104-117 and PLP139-151) and against which increased immune responses have been detected in some multiple sclerosis patients. It is known that attachment of certain types of lipid side chains to peptides can result in their enhanced immunogenicity. The aim of this study was to determine whether thioacylated PLP peptides, as occur in the native protein, are more immunogenic than their nonacylated counterparts, and whether thioacylation influences the development of autoreactivity and experimental autoimmune encephalomyelitis. The results show that in comparison with nonacylated peptides, thioacylated PLP lipopeptides can induce greater T cell and Ab responses to both the acylated and nonacylated peptides. They also enhanced the development and chronicity of experimental autoimmune encephalomyelitis. Synthetic peptides in which the fatty acid was attached via an amide linkage at the N terminus were not encephalitogenic, and they induced greater proportions of CD8(+) cells in initial in vitro stimulation. Therefore, the lability and the site of the linkage between the peptide and fatty acid may be important for induction of encephalitogenic CD4(+) T cells. These results suggest that immune responses induced by endogenous thioacylated lipopeptides may contribute to the immunopathogenesis of chronic experimental demyelinating diseases and multiple sclerosis.

Preprocessing and time-frequency analysis of newborn EEG seizures

Neurological disease or dysfunction in newborn infants is often first manifested by seizures. Prolonged seizures can result in impaired neurodevelopment or even death. In adults, the clinical signs of seizures are well defined and easily recognized. In newborns, however, the clinical signs are subtle and may be absent or easily missed without constant close observation. This article describes the use of adaptive signal processing techniques for removing artifacts from newborn electroencephalogram (EEG) signals. Three adaptive algorithms have been designed in the context of EEG signals. This preprocessing is necessary before attempting a fine time-frequency analysis of EEG rhythmical activities, such as electrical seizures, corrupted by high amplitude signals. After an overview of newborn EEG signals, the authors describe the data acquisition set-up. They then introduce the basic physiological concepts related to normal and abnormal newborn EEGs and discuss the three adaptive algorithms for artifact removal. They also present time-frequency representations (TFRs) of seizure signals and discuss the estimation and modeling of the instantaneous frequency related to the main ridge of the TFR.

Protective role of appendicectomy on onset and severity of ulcerative colitis and Crohn's disease

Background and aims: Recent studies on appendicectomy rates in ulcerative colitis and Crohn's disease have generally not addressed the effect of appendicectomy on disease characteristics. The aims of this study were to compare appendicectomy rates in Australian inflammatory bowel disease patients and matched controls, and to evaluate the effect of prior appendicectomy on disease characteristics. Methods: Patients were ascertained from the Brisbane Inflammatory Bowel Disease database. Controls matched for age and sex were randomly selected from the Australian Twin Registry. Disease characteristics included age at diagnosis, disease site, need for immunosuppression, and intestinal resection. Results: The study confirmed the significant negative association between appendicectomy and ulcerative colitis (odds ratio (OR) 0.23, 95% confidence interval (Cl) 0.14-0.38; p

Patterns of gene expression are altered in the frontal and motor cortices of human alcoholics

Alcoholism is a major health problem in Western countries, yet relatively little is known about the mechanisms by which chronic alcohol abuse causes the pathologic changes associated with the disease. It is likely that chronic alcoholism affects a number of signaling cascades and transcription factors, which in turn result in distinct gene expression patterns. These patterns are difficult to detect by traditional experiments measuring a few mRNAs at a time, but are well suited to microarray analyses. We used cDNA microarrays to analyze expression of approximately 10 000 genes in the frontal and motor cortices of three groups of chronic alcoholic and matched control cases. A functional hierarchy was devised for classification of brain genes and the resulting groups were compared based on differential expression. Comparison of gene expression patterns in these brain regions revealed a selective reprogramming of gene expression in distinct functional groups. The most pronounced differences were found in myelin-related genes and genes involved in protein trafficking. Significant changes in the expression of known alcohol-responsive genes, and genes involved in calcium, cAMP, and thyroid signaling pathways were also identified. These results suggest that multiple pathways may be important for neuropathology and altered neuronal function observed in alcoholism.

Interacting roles of myofibroblasts, apoptosis and fibrogenic growth factors in the pathogenesis of renal tubulo-interstitial fibrosis

The interrelationship between myofibroblasts and fibrogenic growth factors in the pathogenesis of renal fibrosis is poorly defined. A temporal and spatial analysis of myofibroblasts, their proliferation and death, and presence of transforming growth factor-beta1 (TGF-beta1) and platelet-derived growth factor-B (PDGF-B) was carried out in an established rodent model in which chronic renal scarring and fibrosis occurs after healed renal papillary necrosis (RPN), similar to that seen with analgesic nephropathy. Treated and control groups (N = 6 and 4, respectively) were compared at 2, 4, 8 and 12 weeks. A positive relationship was found between presence of tubulo-interstitial myofibroblasts and development of fibrosis. Apoptotic myofibroblasts were identified in the interstitium and their incidence peaked 2 weeks after treatment. Levels of interstitial cell apoptosis and fibrosis were negatively correlated over time (r = -0.57, p < 0.01 ), suggesting that as apoptosis progressively failed to limit myofibroblast numbers, fibrosis increased. In comparison with the diminishing apoptosis in the interstitium, the tubular epithelium had progressively increasing levels of apoptosis over time, indicative of developing atrophy of nephrons. TGF-beta1 protein expression had a close spatial and temporal association with fibrosis and myofibroblasts, whilst PDGF-B appeared to have a closer link with populations of other chronic inflammatory cells such as infiltrating lymphocytes. Peritubular myofibroblasts were often seen near apoptotic cells in the tubular epithelium, suggestive of a paracrine toxic effect of factor/s secreted by the myofibroblasts. In vitro , TGF-beta1 was found to be toxic to renal tubular epithelial cells. These findings suggest an interaction between myofibroblasts, their deletion by apoptosis, and the presence of the fibrogenic growth factor TGF-beta1 in renal fibrosis, whereby apoptotic deletion of myofibroblasts could act as a controlling factor in progression of fibrosis.

Reciprocal relationship between methylation status and loss of heterozygosity at the p14 (ARF) locus in Australian and South African hepatocellular carcinomas

Chromosome 9p21, a locus comprising the tumor suppressor genes (TSG) p16(INK4) (a) and p14(ARF) , is a common region of loss of heterozygosity (LOH) in hepatocellular carcinoma (HCC). p14(ARF) shares exon 2 with p16 in a different reading frame. p14 binds to MDM2 resulting in a stabilization of functional p53 . This study examined the roles of p14, p16 and p53 in hepatocarcinogenesis, in 37 Australian and 24 South African patients. LOH at 9p21 and 17p13.1, p14 and p16 mutation analysis, p14 and p16 promoter methylation and p14, p16 and p53 protein expression was examined. LOH at 9p21 was detected more frequently in South African HCC (P = 0.04). Comparable rates of p53 LOH were observed in Australian and South African HCC (10/22, 45%vs 13/22, 59%, respectively). Hypermethylation of the p14 promoter was more prevalent in Australian HCC than in South African HCC (17/37, 46%vs 7/24, 29%, respectively). In Australian HCC the prevalence of p14 methylation increased with age (P = 0.03). p16 promoter methylation was observed in 12/37 (32%) and 6/24 (25%) in Australian and South African HCC, respectively. Loss of p16 protein expression was detected in 14/36 Australian HCC whereas p53 protein expression was detected in 9/36. Significantly, a reciprocal relationship between 9p21 LOH and p14 promoter hypermethylation was observed (P less than or equal to0.05 ). No significant association between p14 and p53 was seen in this study. The reciprocal relationship identified indicates different pathways of tumorigenesis and likely reflects different etiologies of HCC in the two countries. (C) 2002 Blackwell Science Asia Pty Ltd.