Placental shelf - a common, typically transient and benign finding on early second-trimester sonography.

OBJECTIVE: Placental shelves are believed to represent circumvallate placentae. It is thought that circumvallate placenta may be associated with adverse perinatal outcome when present at delivery. The objective of this study was to determine the prevalence, persistence and significance of placental shelves detected in the early second trimester. METHODS: In 152 consecutive anomaly scans performed between 13 and 16 weeks of gestation, special attention was directed to placental structure and the presence of a placental shelf. When present, a mid-gestation scan was performed to verify if the finding persisted. If so, a third-trimester scan was performed. Delivery charts were reviewed for all cases initially diagnosed with a placental shelf, recording any placenta-related complications. RESULTS: In 17 of 152 (11.2%) early second-trimester scans a placental shelf was detected. In three of these 17 cases the shelf persisted to the 20-22-week scan. In the two cases that presented for the third-trimester scan the shelf was no longer present. In all 17 cases the perinatal outcome was good. CONCLUSIONS: In our study group early second-trimester placental shelves rarely persisted to mid-gestation and never to the third trimester. There were no placenta-related perinatal problems. Early second-trimester placental shelf appears to be a common, benign and transient sonographic finding.

Short- and long-term swimming exercise training increases myocardial insulin-like growth factor-I gene expression.

UNLABELLED: OBJECTIVES. We investigated the effect of short- and long-term swimming exercise, with or without insulin-like growth factor (IGF)-I administration, on the expression of myocardial IGFs and contractile proteins. METHODS: Sprague-Dawley male rats (n=36) were subjected to swimming exercise for 2 or 6 weeks. IGF-I (0.5mg/rat) was administered continuously for 1 week, using alzet osmotic pumps. Control groups remained sedentary. IGF-I, IGF-I receptor (IGF-IR), IGF-II, skeletal alpha-actin (sk-actin), and beta myosin heavy chain (beta MHC) mRNAs were measured using Northern blot analysis and RT-PCR. RESULTS: A significant 2-fold increase in myocardial IGF-I mRNA was found after 2 and 6 weeks of swimming in both IGF-I treated and untreated rats (p<0.001). IGF-IR mRNA was significantly (p<0.05) increased after 6 weeks of training only in the IGF-I treated animals. IGF-II mRNA remained unchanged at all time points. While beta MHC mRNA was significantly decreased (p=0.003) at 2 and 6 weeks, sk-actin mRNA remained unchanged. CONCLUSIONS: Short- and long-term swimming exercise training increase myocardial expression of IGF-I mRNA. Exogenous administration of IGF-I, during the first week of the exercise session, did not produce any effect on myocardial IGF-I but was associated with increased IGF-IR signal after the long-term exercise training. These data suggest a relationship between IGF-I expression and cardiac adaptation to exercise training.

Histologic atrial myolysis is associated with atrial fibrillation after cardiac operation.

BACKGROUND: Postoperative atrial fibrillation after cardiac operation is common. Despite the identification of risk factors associated with postoperative atrial fibrillation, the pathophysiologic mechanisms remain unclear. Myolysis has been recently described to be associated with maintenance of atrial fibrillation in experimental animals. In this study, we attempted to identify histopathologic changes in atria that might predict the development of postoperative atrial fibrillation, and specifically address its association with myolysis. METHODS: Right appendicular atrial tissue was sampled before and after cardiopulmonary bypass from 60 patients in sinus rhythm who underwent elective coronary artery bypass grafting. RESULTS: Fifteen patients (25%) developed postoperative atrial fibrillation. Histopathologic abnormalities were found in most patients (52 of 60). However, only myolysis and lipofuscin levels were found to be an independent histologic finding associated with the development of postoperative atrial fibrillation. Electron microscopy showed that myolytic vacuoles were not membrane bound, and were associated with lipofuscin deposits. Neither mitochondrial pathology nor apoptosis was detected in the atria before or after operation. CONCLUSIONS: Abnormalities in biopsies before cardiopulmonary bypass can indicate the susceptibility to develop postoperative atrial fibrillation. This implies that the status of the atrium before cardiopulmonary bypass is a major determinant in the development of this common complication.

Effects of senescence and citral on neuronal vacuolar degeneration in rat pelvic ganglia.

A significant part of the morbidity in elderly men involves pelvic organs and their autonomic neural regulation. Environmental stimuli also impair the structure and function of pelvic organs. One of these factors is citral, a widely-used cosmetic fragrance constituent, which causes severe prostatic hyperplasia in rats. In this study, we assessed the effect of topical administration of citral (30 days) on the morphology of pelvic ganglia (PG) in young adult and old Wistar rats. Neuronal vacuolar degeneration with preserved nuclei of PG neurons was observed in untreated senescent, but not young rats. Citral significantly increased the rate of vacuolated neurons in old rats (from 3 to 14%), but only slightly in young ones (from 0 to 0.5-0.3%). Similar lesions were not found in inferior cervical or celiac ganglia, in either group. This shows that environmental stimuli enhance age-related processes of vacuolar neuronal degeneration in PG, and may contribute to the dysfunction of pelvic organs in the elderly.

Dopamine increases glial cell line-derived neurotrophic factor in human fetal astrocytes.

The use of fetal astrocytes for gene delivery into brains with neurodegenerative diseases has been suggested. Therefore, the effects of neurotransmitters in the brain on such cells are of interest. The presence of D1(D1A) receptors and the effect of dopamine on a fetal human astrocyte cell line (SVG cells) in vitro were examined. SVG cells expressed D1(D(1A)), but not D5(D1B) receptors, as shown by RT-PCR. Exposure to dopamine, apomorphine, and the specific D1 agonist, SKF-38393, increased glial-derived neurotrophic factor production of SVG cells, as well as intracellular free calcium. Exposure to the specific D1 antagonist, SCH 23390, blocked these effects. Thus, if implanted into a brain region rich in dopamine, or if transfected with the tyrosine hydroxylase gene, fetal astrocytes may serve as paracrine/autocrine cells capable of supplying critical growth factors to diseased brain tissue.

Functional analysis of mutations in SLC7A9, and genotype-phenotype correlation in non-Type I cystinuria.

Cystinuria (OMIM 220100) is a common recessive disorder of renal reabsorption of cystine and dibasic amino acids that results in nephrolithiasis of cystine. Mutations in SLC3A1, which encodes rBAT, cause Type I cystinuria, and mutations in SLC7A9, which encodes a putative subunit of rBAT (b(o,+)AT), cause non-Type I cystinuria. Here we describe the genomic structure of SLC7A9 (13 exons) and 28 new mutations in this gene that, together with the seven previously reported, explain 79% of the alleles in 61 non-Type I cystinuria patients. These data demonstrate that SLC7A9 is the main non-Type I cystinuria gene. Mutations G105R, V170M, A182T and R333W are the most frequent SLC7A9 missense mutations found. Among heterozygotes carrying these mutations, A182T heterozygotes showed the lowest urinary excretion values of cystine and dibasic amino acids. Functional analysis of mutation A182T after co-expression with rBAT in HeLa cells revealed significant residual transport activity. In contrast, mutations G105R, V170M and R333W are associated to a complete or almost complete loss of transport activity, leading to a more severe urinary phenotype in heterozygotes. SLC7A9 mutations located in the putative transmembrane domains of b(o,+)AT and affecting conserved amino acid residues with a small side chain generate a severe phenotype, while mutations in non-conserved residues give rise to a mild phenotype. These data provide the first genotype-phenotype correlation in non-Type I cystinuria, and show that a mild urinary phenotype in heterozygotes may associate with mutations with significant residual transport activity.

Spontaneous hyperplasia of the ventral lobe of the prostate in aging genetically hypertensive rats.

Recent studies have shown that the prostatic autonomic innervation takes part in its homeostasis and growth. Other works showed that spontaneously hypertensive rats (SHR) show excessive sympathetic activity, accompanied by lower urinary tract symptoms, increased growth capacity of prostatic stromal cells, and increased levels of androgens and their receptors. Furthermore, young SHR were reported to present incipient stages of benign prostatic hyperplasia (BPH). The aim of the present study was to examine whether this strain indeed develops spontaneous BPH with age, and can thus serve as a genuine natural model for this disorder. For this purpose, ventral lobes of prostates of one-year-old, male SHR and their normotensive counterparts, Wistar Kyoto (WKY) rats, were examined histopathologically, and the degree of hyperplasia was evaluated according to a score-chart protocol (histoscore). SHR exhibited severe adenomatous spontaneous BPH, characterized by piling-up of epithelial cells, with papillary formations, accompanied by a mild increase in the amount of fibrocytes and smooth muscle cells in the stroma. This was reflected by histoscore values of 38 +/-2. Thickening of prostatic arterioles also was noted, as well as mild chronic inflammatory exudate. WKY rats did not show any of these features of BPH despite their age (histoscore 17 +/- 3, significantly different from that of SHR). We conclude that SHR can serve as a rodent model for the spontaneous development of BPH with age, most probably due to the excessive neuroendocrine activity characteristic of this rat strain.

Potential preoperative markers for the risk of developing atrial fibrillation after cardiac surgery.

Postoperative atrial arrhythmias after cardiac surgical procedures are common, with a reported overall incidence of approximately 50%. The pathophysiological mechanisms responsible for atrial fibrillation after a cardiac procedure remain unclear, although several clinical studies published during the past decade have identified certain preoperative risk factors associated with postoperative atrial fibrillation. In this study, we attempted to identify the histopathological changes in atrial cardiomyocytes that might predict the development of atrial fibrillation during the postoperative period. Atrial tissue from 60 patients was sampled before and after a cardiopulmonary bypass. Fifteen patients (25%) developed postoperative atrial fibrillation. The only clinical independent risk factor for the development of postoperative atrial fibrillation was chronic obstructive pulmonary disease (COPD) (P = .037). Histologically, there were 3 findings in the atrial myocardium that were more common in patients who developed postoperative atrial fibrillation: (1) vacuolation size (P = .017), (2) vacuolation frequency (P = .0136), and (3) lipofuscin content (P = .013). The identification of these histological markers for the development of postoperative atrial fibrillation may contribute not only to our understanding of the underlying pathophysiology that leads to postoperative atrial fibrillation but also to a method of preventing this troublesome complication of cardiac surgery.

Non-type I cystinuria caused by mutations in SLC7A9, encoding a subunit (bo,+AT) of rBAT.

Cystinuria (MIM 220100) is a common recessive disorder of renal reabsorption of cystine and dibasic amino acids. Mutations in SLC3A1, encoding rBAT, cause cystinuria type I (ref. 1), but not other types of cystinuria (ref. 2). A gene whose mutation causes non-type I cystinuria has been mapped by linkage analysis to 19q12-13.1 (Refs 3,4). We have identified a new transcript, encoding a protein (bo, +AT, for bo,+ amino acid transporter) belonging to a family of light subunits of amino acid transporters, expressed in kidney, liver, small intestine and placenta, and localized its gene (SLC7A9) to the non-type I cystinuria 19q locus. Co-transfection of bo,+AT and rBAT brings the latter to the plasma membrane, and results in the uptake of L-arginine in COS cells. We have found SLC7A9 mutations in Libyan-Jews, North American, Italian and Spanish non-type I cystinuria patients. The Libyan Jewish patients are homozygous for a founder missense mutation (V170M) that abolishes b o,+AT amino-acid uptake activity when co-transfected with rBAT in COS cells. We identified four missense mutations (G105R, A182T, G195R and G295R) and two frameshift (520insT and 596delTG) mutations in other patients. Our data establish that mutations in SLC7A9 cause non-type I cystinuria, and suggest that bo,+AT is the light subunit of rBAT.

Induction of atypical prostatic hyperplasia in rats by sympathomimetic stimulation.

BACKGROUND: Prostatic innervation may participate in its homeostasis and growth. alpha-Adrenergic inhibition alleviates clinical symptoms in benign prostatic hyperplasia. However, the prostatic effect of adrenergic agonists has not been investigated. This study deals with the prostatic effect of subchronic sympathomimetic stimulation. METHODS: Male rats received daily subcutaneous injections of the alpha-adrenergic agonist phenylephrine, 1, 10, or 20 mg/kg per day, the beta-adrenergic agonist isoproterenol, 1, 2.5 or 5 mg/kg per day, or saline, for 30 days, and the prostates were removed for histopathological examination. RESULTS: Phenylephrine induced atypical prostatic hyperplasia, characterized by piling-up with papillary and cribriform patterns, and budding-out of epithelial cells. It decreased prostatic secretions and total weight. Similar results were observed in orchidectomized rats receiving exogenous testosterone supplementation. Isoproterenol had no prostatic morphological effect. CONCLUSIONS: These results raise the possibility that sympathetic stimuli play a role in normal and aberrant growth and differentiation of prostatic epithelium, and suggests neurostimulants-treated animals as a model to study the etiology and development of prostatic hyperplasia.

Molecular analysis of cystinuria in Libyan Jews: exclusion of the SLC3A1 gene and mapping of a new locus on 19q.

Cystinuria is a hereditary disorder of amino acid transport and is manifested by the development of kidney stones. In some patients the disease is caused by mutations in the SLC3A1 gene, which is located on the short arm of chromosome 2 and encodes a renal/intestinal transporter for cystine and the dibasic amino acids. In Israel cystinuria is especially common among Jews of Libyan origin. After excluding SLC3A1 as the disease-causing gene in Libyan Jewish patients, we performed a genomewide search that shows that the Libyan Jewish cystinuria gene maps to the long arm of chromosome 19. Significant linkage was obtained for seven chromosome 19 markers. A maximal LOD score of 9.22 was obtained with the marker D19S882. Multipoint data and recombination analysis placed the gene in an 8-cM interval between the markers D19S409 and D19S208. Significant linkage disequilibrium was observed for alleles of four markers, and a specific haplotype comprising the markers D19S225, D19S208, D19S220, and D19S422 was found in 11 of 17 carrier chromosomes, versus 1 of 58 Libyan Jewish noncarrier chromosomes.

Mutations in the SLC3A1 transporter gene in cystinuria.

Cystinuria is an autosomal recessive disease characterized by the development of kidney stones. Guided by the identification of the SLC3A1 amino acid-transport gene on chromosome 2, we recently established genetic linkage of cystinuria to chromosome 2p in 17 families, without evidence for locus heterogeneity. Other authors have independently identified missense mutations in SLC3A1 in cystinuria patients. In this report we describe four additional cystinuria-associated mutations in this gene: a frameshift, a deletion, a transversion inducing a critical amino acid change, and a nonsense mutation. The latter stop codon was found in all of eight Ashkenazi Jewish carrier chromosomes examined. This report brings the number of disease-associated mutations in this gene to 10. We also assess the frequency of these mutations in our 17 cystinuria families.

Pulmonary and renal neutral endopeptidase EC 3.4.24.11 in rats with experimental heart failure.

Congestive heart failure is characterized by avid sodium retention and a blunted renal response to exogenous and endogenous atrial natriuretic peptide. Inhibition of neutral endopeptidase EC 3.4.24.11, the main enzyme that degrades natriuretic peptides, produces a natriuretic response in different models of congestive heart failure. This raises the possibility that an increase in either the expression or activity of neutral endopeptidase is responsible for these phenomena. In the present study, we examined (1) the renal effects of SQ-28,603, a neutral endopeptidase inhibitor, in rats with moderate and severe congestive heart failure induced by an aortocaval fistula compared with sham controls, and (2) neutral endopeptidase expression and activity in the lungs and kidneys of these rats. Infusion of SQ-28,603 (40 mg/kg IV) induced a significant natriuretic response in normal rats and rats with moderate congestive heart failure. This response was blunted in rats with severe congestive heart failure. Surprisingly, renal neutral endopeptidase mRNA levels, assessed by quantitative reverse transcriptase-polymerase chain reaction; protein levels, assessed by Western blotting; and activity, assessed by gelatin gels, were comparable in all groups. Pulmonary neutral endopeptidase mRNA levels decreased by 45% in rats with severe congestive heart failure but not in rats with mild congestive heart failure. In addition, pulmonary neutral endopeptidase immunoreactivity levels and activity were significantly decreased in congestive heart failure in correlation with the severity of the disorder.(ABSTRACT TRUNCATED AT 250 WORDS)

Functional alpha 3-glycine receptors in rat adrenal.

The adrenal medulla contains high-affinity strychnine binding sites, presumed to be receptors for glycine. In this study, glycine injection (400 pmol) via a cannula attached to a microdialysis probe increased in vivo concentrations of catecholamines in the adrenal microdialysate in anesthetized rats. Strychnine perfusion (20 pmol/20 min) blocked these responses. To identify receptors potentially mediating this effect, we tested for RNA transcripts of the three known alpha subunits of strychnine binding site, using the reverse transcription-polymerase chain reaction. Only mRNA encoding the alpha 3 isoform was found in the rat adrenal. The findings suggest that in the rat adrenal, glycine stimulates catecholamine release by binding to strychnine binding sites and that those sites probably contain the alpha 3 isoform.

Angiotensin II maintains, but does not mediate, isoproterenol-induced cardiac hypertrophy in rats.

The role of angiotensin II (ANG II) in the development of isoproterenol (Iso)-induced cardiac hypertrophy was examined in rats. Iso increased cardiac mass, left ventricular RNA-to-DNA ratio, and the cardiac content of both myosin heavy chain and hydroxyproline in a dose-dependent manner, indicating that Iso-induced cardiac hypertrophy involves growth of both muscle and connective tissue. Cardiac hypertrophy reverted within 11-14 days after cessation of Iso. Propranolol prevented development of Iso-induced cardiac hypertrophy but did not affect the rate of its reversal. The ANG II receptor blocker losartan (Los) did not significantly decrease the hypertrophic response to Iso. Los injected after cessation of Iso dramatically enhanced the reversal of cardiac hypertrophy, even in rats that received Los with Iso during the induction of Iso-induced cardiac hypertrophy. ANG II, injected continuously at a subpressor dose that did not affect heart weight when given alone, inhibited reversal of cardiac hypertrophy when given after cessation of Iso. Los did not significantly affect the induction of the protooncogene c-fos by Iso. We conclude that endogenous ANG II has a major function in maintaining Iso-induced cardiac hypertrophy but does not mediate its induction. This suggests that different interactive stimuli may be required for development of cardiac hypertrophy, i.e., for initiation and for maintenance.

Hydrolysis of iodine labelled urodilatin and ANP by recombinant neutral endopeptidase EC. 3.4.24.11.

1. Urodilatin is a 32 amino-acid peptide of similar sequence to atrial natriuretic peptide (ANP), with four additional amino-acids at the N-terminus. Although ANP and urodilatin bind to the same receptors with similar affinities, urodilatin is more active than ANP as a natriuretic agent. Previous studies, using neutral endopeptidase EC 3.4.24.11 (NEP) derived from crude membrane preparations, were inconclusive, but suggested that urodilatin was more resistant than ANP to degradation by this enzyme. In the present study, we compared the degradation rates of [125I]-urodilatin and [125I]-ANP by pure recombinant NEP (rNEP). 2. Incubation of radioactively labelled ANP with rNEP resulted in a much more rapid degradation of the peptide than that for labelled urodilatin. 3. Both phosphoramidon and SQ-28,603, potent inhibitors of NEP, completely protected both peptides from metabolism by rNEP. 4. The circular dichroism spectra of the two peptides indicate that they are very similar and exist largely in unordered or flexible conformations. 5. These results support the relative resistance of urodilatin to NEP, and indicate that urodilatin may be of use as a therapeutic agent, in conditions in which ANP is ineffective.

Duration of spinal anaesthesia is determined by the partition coefficient of local anaesthetic.

We have compared the duration of motor block produced by four local anaesthetics administered into a chronically implanted subarachnoid catheter in rabbits. Each group (n = 6) received four different doses of amethocaine, bupivacaine, lignocaine or procaine, and the duration of the resulting motor block was assessed. Dose-response curves were plotted for each drug. As a measure of activity of the anaesthetics, we used the dose of each drug required to produce block of 60-min duration (D60 min) and the correlation between D60 min and different drug properties was examined. An inverse linear correlation (r = 0.995; P < 0.01) was observed between log D60 min and the log of the partition coefficient of the local anaesthetics. No correlation was found between the effect and degree of protein binding, pKa or molecular weight. These results suggest that, in spinal anaesthesia, the partition coefficient could be used as a predictor of the duration of anaesthetic action.