Localized unilateral perirenal fibrosis: CT and MRI appearances

We report a rare case of localized perirenal retroperitoneal fibrosis (RPF) in a woman presenting with anemia. The increased diagnostic capabilities and imaging characteristics of CT and MRI are emphasized. Extensive search through the literature revealed that perirenal distribution of RPF has been reported in eight cases, being unilateral in only three. Electronic Publication     

Serum leptin concentrations during the perinatal period

We aimed to study maternal and infant serum leptin concentrations during the perinatal period and their relationship to the body weight of mothers and newborns. Serum leptin values were measured by enzyme-linked immunoadsorbent assay (ELISA) (R&D systems) in 26 healthy, term neonates during the first (N1) and fifth (N5) day after birth and were compared with serum leptin values in maternal blood (MS), amniotic fluid (AF), and umbilical cord (UC) at delivery. Twenty-five healthy, nonpregnant women, age and body weight-matched to the mothers, were used as controls (C). Infant serum leptin concentrations declined significantly after birth from UC to the N5 samples (p<0.003). MS leptin values were significantly higher than UC, N1, N5, and C values (p<0.001), while AF values were significantly lower than in controls (p<0.001). UC, but not MS leptin values correlated significantly with the birth weight of infants (r = 0.6; p<0.03). The elevated values of leptin in maternal serum and the regressing pattern of infant leptin values after birth suggest an additional, probably placental source of this protein during pregnancy, possibly contributing to the regulation of fetal body weight.     

Sensitization to amphetamine,but not PCP,impairs attentional set shifting: reversal by a D<Subscript>1</Subscript> receptor agonist injected into the medial prefrontal cortex

Rationale Repeated exposure to psychomotor stimulants can lead to sensitization to their effects, and sensitization has been implicated in the pathophysiology of schizophrenia and drug abuse. These disorders are characterized by cognitive deficits, particularly in prefrontally mediated executive function.Objective The present experiments were conducted to investigate the effects of sensitizing regimens of amphetamine and phencyclidine (PCP) on attentional set shifting.Methods Rats received injections of amphetamine, PCP or saline three times per week for 5 weeks. Four weeks later, rats were trained to dig for food in one of two bowls, each bowl having an odour and a texture. Only one dimension (odour or texture) correctly predicted which bowl was baited. Rats were then tested on a series of discriminations including those requiring an intra-dimensional shift (IDS), an extra-dimensional shift (EDS) or a reversal of previously relevant and irrelevant stimuli.Results Rats sensitized to amphetamine performed normally on the IDS, but were impaired on the EDS, as well as on reversal discriminations. PCP-sensitized rats were unaffected on any of the discriminations. In amphetamine-sensitized rats the deficit at the EDS stage was reversed by infusion of the D₁ receptor agonist SKF38393 into the medial prefrontal cortex (mPFC).Conclusions Results show that the amphetamine-sensitized state impairs prefrontally mediated attentional set shifting. This is consistent with cognitive deficits in schizophrenia and addiction, and with the evidence that amphetamine sensitization is accompanied by functional changes in the mPFC. These results further add to a growing literature showing that activating D₁ receptors in the mPFC improves aspects of cognition.     

Reconditioning of drug-related cues: a potential contributor to relapse after drug reexposure

To investigate the process of relapse to drug seeking caused by reexposure to drugs, we studied the consequences of recurring instances of stimuli–drug associations using heroin conditioned place preference (CPP) in rats. After original conditioning and extinction, rats received either a single compartment–heroin pairing (reconditioning) or were primed with heroin and tested for reinstatement of CPP. It was found that the session of reconditioning, but not the session of reinstatement, caused the reappearance of a preference for the heroin-paired compartment on a test given 24 h later, in drug-free conditions. The effect of reconditioning was found to be dependent on heroin doses, and was not seen when heroin injections were given outside the conditioning environment. Furthermore, a single session of reconditioning elevated heroin seeking even on a test given 96 h later. Finally, heroin seeking was found to be significantly elevated on a test given 28 days after the last extinction session whether animals received 1 or 3 reconditioning sessions. These results suggest that the motivational value of cues associated with heroin is not eliminated by extinction and, importantly, that these cues can rapidly regain their ability to promote drug seeking behavior if they are re-associated with the effect of heroin.     

Electrostimulation for the prevention of deep venous thrombosis in patients with major trauma: a prospective randomized study

BACKGROUND: Current methods of posttraumatic thromboprophylaxis (heparins and sequential compression devices) are inadequate. New methods should be tested. Muscle electrostimulation (MEST) has been used over the years with mixed-but predominantly encouraging-results for a variety of conditions, including prevention of deep venous thrombosis (DVT). It has not been tested in multiple trauma patients. METHODS: Trauma patients with Injury Severity Score higher than 9 who were admitted to the intensive care unit and had a contraindication for prophylactic heparinization were randomized to groups MEST and control. MEST patients received 30-minute MEST sessions twice daily for 7 to 14 days. Venous flow velocity and venous diameter were measured by duplex venous scan. Venography-or, if not available, duplex-was used to evaluate the presence of proximal and peripheral DVT between days 7 and 15. RESULTS: After exclusions, 26 MEST and 21 control patients completed the study and received outcome evaluation by venography (25) or duplex (22). Three patients in each group developed proximal DVT (11.5% vs 14%, P = .79), and an additional 4 (15%) MEST group and 3 (14%) control group patients developed peripheral DVT ( P = .96). There was no difference in venous flow velocity or venous diameter between the groups. CONCLUSIONS: MEST was not effective in decreasing DVT rates in major trauma patients.