Simple and configural association learning in rats with bilateral quisqualic acid lesions of the nucleus basalis magnocellularis

We hypothesized that bilateral quisqualic acid lesions of the nucleus basalis magnocellularis (NBM) in rats would impair configural but not simple association learning. In experiment 1, rats were tested in a negative patterning operant discrimination where they were food-reinforced for responding to a light or a tone (L+, T+) but not for responding to the configural stimulus consisting of the light and tone presented simultaneously (LT-). Consistent with our hypothesis, NBM-lesioned rats showed a transient but significant impairment, responding normally to L+ and T+ but responding more often to LT-, in addition to responding more often during the inter-trial interval (ITI) than controls. In experiment 2, rats were tested in a simple operant discrimination where rats were food-reinforced for responding to a light (L+) but not for responding to a tone (T-). Although NBM-lesioned rats again responded normally to L+ as predicted, NBM-lesioned rats were transiently impaired, making more T- responses and more ITI responses than controls. Together, these results suggest that the NBM is involved in both configural and simple association learning but that this involvement is limited to learning to withhold responding to non-reinforced contextual or discrete stimuli. Finally, rats from experiment 2 underwent extinction trials, where results showed no difference between NBM-lesioned and control groups, suggesting that the NBM is not involved in the extinction of conditioned responding to previously reinforced stimuli.     

The relationship between maternal use of heroin and methadone and infant birth weight

AIMS/DESIGN: Reduction in mean birth weight and increased incidence of low birth weight are both associated with exposure to illicit heroin in pregnancy. Many studies examining neonatal outcomes in pregnant heroin users treated with methadone report improvements in birth weight. As a consequence, methadone treatment has become the 'gold standard' for the management of the pregnant heroin user. However, not all studies report significant birth weight increases associated with methadone. We undertook a number of meta-analyses on reduction in mean birth weight and incidence of low birth weight to estimate more precisely the effect of illicit heroin and methadone. FINDINGS: Results showed mean reduction in birth weight associated with heroin use: 489 g (95% CI 284-693 g), compared with methadone: 279 g (229-328 g). Similarly, the pooled relative risk estimate for low birth weight for maternal heroin use was 4.61 (95% CI 2.78-7.65), compared with 1.36 (0.83-2.22) for methadone. Analysis of data on combined heroin and methadone use produced a pooled mean reduction in birth weight of 557 g (403-710 g), with a pooled relative risk estimate for low birth weight of 3.28 (2.47-4.39). Pooling 'any' methadone data, regardless of heroin use, produced an estimated reduction in birth weight of 395 g (311-478 g) and a relative risk estimate for low birth weight of 1.90 (1.29-2.81). Combining all data in an 'any' opiate use analysis also produced a mean reduction in birth weight of 483 g (386-583 g) and a relative risk estimate for low birth weight of 3.81 (2.57-5.65). CONCLUSIONS: The current findings suggest that heroin use while receiving methadone may counteract the birth weight advantage gained from methadone alone. Whether this is due to fetal exposure to heroin plus methadone, to reduced antenatal care, other behavioural and environmental factors associated with concurrent use of heroin and methadone or a combination of these is unclear. Nevertheless, these results challenge the current belief that the pregnant user is always better off receiving methadone than not, and suggests that methadone may not be the appropriate treatment for the pregnant women who continue to use illicit heroin.     

Mimics of Ebstein's anomaly

The purpose of this study was to determine the most discriminating clinical and echocardiographic features that are most helpful in correctly identifying Ebstein's anomaly of the tricuspid valve from other causes of tricuspid regurgitation. Ebstein's anomaly is an uncommon malformation of the tricuspid valve with diagnostic echocardiographic features. Other cardiac disorders associated with tricuspid valve regurgitation and predominate right-sided heart chamber enlargement can be misdiagnosed as Ebstein's anomaly. All patients who were referred to our institution between 1982 and 1995 with the diagnosis of Ebstein's anomaly but were found to have other abnormalities of the tricuspid value or right ventricle were identified. Their clinical, echocardiographic, and surgical records were reviewed retrospectively. Twenty-two patients (12 males and 10 females), aged 7 to 68 years (mean 33 years), were referred to our institution with the diagnosis of Ebstein's anomaly but were found to have another abnormality that mimicked clinical and diagnostic features of Ebstein's anomaly. The most common initial symptom was exercise intolerance (13 [59%] patients) followed by atrial arrhythmia (seven [32%] patients). Two patients had cyanosis. Three patients had paroxysmal and six had chronic atrial fibrillation/flutter. Cardiomegaly on chest x-ray film was noted in 18 (82%) patients. Referral diagnosis of Ebstein's anomaly had been made by echocardiography (12 patients), cardiac catheterization (four patients), both techniques (five patients), and echocardiography and magnetic resonance imaging (one patient). All 22 patients had predominate right atrial and right ventricular enlargement, and 18 (82%) of 22 patients also had right ventricular dysfunction. However, Ebstein's anomaly was confidently ruled out with repeat comprehensive echocardiography at our institution by establishing (1) absence of significant apical displacement of the septal tricuspid valve leaflet (> or = 8 mm/m2) and (2) lack of a redundant, elongated, anterior tricuspid valve leaflet in all 22 patients (100%). All had significant tricuspid regurgitation caused by tricuspid valve dysplasia (nine patients), tricuspid valve prolapse (four patients), trauma (four patients), right ventricular dysplasia (three patients), endocarditis (one patient), and annular dilation caused by free pulmonary regurgitation (one patient). In all 15 patients who subsequently underwent surgery (tricuspid valve repair [seven patients] or replacement [eight patients]), the absence of Ebstein's anomaly was confirmed. Echocardiographic absence of the characteristic degree of displacement of the septal leaflet of the tricuspid valve (> or = 8 mm/m2) and the presence of a nonelongated, nonredundant anterior tricuspid valve leaflet consistently excluded the diagnosis of Ebstein's anomaly. Under such circumstances, other anomalies of the tricuspid valve or right ventricle were consistently identified. Recognition of the mimics of Ebstein's anomaly had important surgical implications.     

Testing bone implants in cell lines and human osteoblasts]

An innovative technology, BladderScan, was introduced to reduce urinary tract infections and care costs in hospitalized adults. Evaluation revealed reductions in infection rates and overall benefits exceeding costs.     

Effect of trabecular aspiration on early intraocular pressure rise after cataract surgery

The enzyme/cytokine thymidine phosphorylase/platelet-derived endothelial cell growth factor (TP/PD-ECGF) has diverse functions within cells, including the regulation of steady-state thymidine levels, the conversion of the cancer chemotherapeutic agent 5-fluorouracil (FUra) to an active metabolite, and the mediation of angiogenesis in normal and malignant cells. Although the levels of TP/PD-ECGF vary substantially among different tissues and are generally found to be elevated in tumors, little is known about the control of its expression in vivo in humans. In this study, peripheral blood mononuclear cells were obtained from patients prior to and during treatment with IFN and FUra and analyzed for TP/PD-ECGF expression. Sixteen of 21 patients (76%) exhibited an average 3-4-fold increase of TP/PD-ECGF protein levels after treatment with either IFN-alpha or-beta, with the remaining patients having either a decrease (four patients) or no change (one patient) at the sampling times examined. Expression in vivo increased rapidly within 1-2 h of IFN treatment and remained elevated for up to 48 h after its administration. The increase in TP/PD-ECGF protein was accompanied by a concomitant increase in TP/PD-ECGF mRNA levels. TP/PD-ECGF mRNA expression in cells in vitro was induced by IFN but not by pharmacologically relevant concentrations of FUra, suggesting that the IFN was responsible for the induction seen in the patients. This study demonstrates that IFN induces TP/PD-ECGF expression in vivo by regulation of the level of mRNA expression.     

Congenital calcified thrombosis of inferior vena cava, bilateral renal veins and left spermatic vein

An infant with severe congenital calcified thrombosis in the inferior vena cava, bilateral renal veins and left spermatic vein is presented. Five previously published cases and pertinent points concerning this rare occurence are discussed. The etiology of this calcified thrombosis remained unknown.