Longitudinal studies of time‐dependent changes in both bladder and erectile function after streptozotocin‐induced diabetes in Fischer 344 male rats

OBJECTIVES

To provide sensitive physiological endpoints for the onset and long‐term progression of deficits induced by diabetes mellitus (DM) in bladder and erectile function in male rats, and to evaluate parallel changes in urogenital and nerve function induced by hyperglycaemia over a protracted period as a model for chronic deficits in patients with diabetes.

MATERIALS AND METHODS

The study comprised in 877 male, 3‐month‐old, Fischer 344 rats; 666 were injected intraperitoneally with 35 mg/kg streptozotocin (STZ) and divided into insulin‐treated and untreated diabetic groups. The rats were studied over 8 months and measurements made of both erectile and bladder function, as well as nerve conduction studies over the duration of the study.

RESULTS

There was an early (first month) abnormality of both erectile and bladder function that persisted through the 8 months of the study. The erectile dysfunction was manifest as reduced intracavernous pressure/blood pressure ratio, and the bladder dysfunction as a persistent increase in detrusor overactivity with no detrusor decompensation. Insulin treatment prevented or modified the abnormality in each organ. Hyperglycaemia caused a progressive decrease in caudal nerve conduction velocity. The mean digital sensory and tibial motor nerve conduction velocity did not deteriorate over time. Correlation measurements of nerve and organ function were not consistent.

CONCLUSIONS

The results of this extensive long‐term study show early and profound effects of hyperglycaemia on the smooth muscle of the penis and bladder, that were persistent and stable in surviving rats over the 8 months. The physiological changes did not correlate well with neurological measurements of those organs. Significantly, diverse smooth‐muscle cellular and subcellular events antedated the measured neurological manifestations of the hyperglycaemia by several months. Although autonomic diabetic neuropathy is a primary life‐threatening complication of long‐term diabetes in humans, this rat model of STZ‐induced diabetes showed that the rapid onset of physiological manifestations was based on many molecular changes in the smooth muscle cells in this model of type 1 DM.     

Pathogenesis of simian immunodeficiency virus-induced alterations in macaque trigeminal ganglia

Peripheral neuropathy is the most frequent neurologic complication associated with human immunodeficiency virus (HIV) infection, yet its pathogenesis remains poorly understood. To study the mechanisms causing HIV-induced peripheral nervous system disease, we examined trigeminal ganglia obtained from simian immunodeficiency virus (SIV)-inoculated macaques. SIV-infected macaques developed multifocal trigeminal ganglionitis of varying severity characterized by multifocal mononuclear infiltrates, neuronophagia, and neuronal loss resembling reports of HIV-associated changes present in dorsal root ganglia. Neuronal density, measured by calculating the fractional area of trigeminal ganglia occupied by neurons, was significantly lower in SIV-infected macaques versus uninfected macaques (p = 0.001). To characterize the inflammatory cell population and measure productive viral infection in ganglia, trigeminal ganglia from SIV-infected macaques were immunostained for macrophage or cytotoxic lymphocyte markers and for SIV gp41. The extent of macrophage infiltration in trigeminal ganglia was inversely correlated with neuronal loss (p = 0.001), whereas cytotoxic lymphocyte infiltration was not associated with neuronal loss. These studies demonstrate that alterations in the somatosensory ganglia of SIV-infected macaques closely parallel those observed in HIV-infected individuals and show that study of SIV-infected macaques may help elucidate the pathophysiology of HIV-induced peripheral neuropathy.     

Coffee consumption and reduced risk of hepatocellular carcinoma: findings from the Singapore Chinese Health Study

Background  

Coffee consumption has been associated with reduced markers of hepatic cell damage, reduced risk of chronic liver disease, and cirrhosis across a variety of populations. Data on the association between coffee consumption and risk of hepatocellular carcinoma (HCC), especially in high-risk populations, are sparse.     

Effect of Ropinirole on Sleep Outcomes in Patients with Restless Legs Syndrome: Meta-Analysis of Pooled Individual Patient Data from Randomized Controlled Trials

Study Objective. To compare the effects of ropinirole with those of placebo on sleep, as evaluated by specific domains of the Medical Outcomes Study (MOS) sleep scale, as well as the Clinical Global Impression-Improvement (CGI-I) scale, in patients with restless legs syndrome (RLS). Design. Meta-analysis of six randomized, double-blind, placebo-controlled, parallel-group trials conducted in the United States and Europe. Patients. A total of 1679 patients aged 18–79 years with primary moderate-to-severe RLS who received ropinirole (835 patients) or placebo (844 patients). Measurements and Main Results. A systematic review of MEDLINE (January 1980-January 2007) and clinical trial registers was performed to identify placebo-controlled trials of ropinirole that used the 12-item MOS sleep scale to assess sleep in patients with RLS. Individual patient data from both published and nonpublished trials were pooled for meta-analysis. In the eligible studies, immediate-release ropinirole 0.25-6 mg or placebo had been given for at least 12 weeks. In addition, sleep scale summary scores for the domains of sleep quantity, adequacy, disturbance, and daytime somnolence had to have been assessed at baseline and at 12 weeks. Our meta-analysis found that at baseline study patients slept an average of 5.8 hours/night. At the end of 12 weeks, ropinirole-treated patients slept a mean of 2.5 hours/week more and had a 21% greater improvement from baseline in sleep adequacy scores compared with patients receiving placebo. Ropinirole-treated patients also had 14% less sleep disturbance and 8% less daytime somnolence than patients receiving placebo. Clinicians rated 63% of ropinirole-treated patients and 47% of patients receiving placebo as responders based on the CGI-I scale. Mixed effects analysis of covariance was used to estimate treatment effect adjusting for study center as a random effect, as well as the following fixed effects known to affect sleep: baseline sleep characteristics, age, sex, and chronic medical conditions. All differences were statistically significant (p<0.05), even after adjusting for multiple comparisons. Conclusion. Pooled data from six similarly designed clinical trials provide evidence that ropinirole improves sleep quantity and adequacy, and lessens sleep disturbance and daytime somnolence in patients with primary RLS.     

Neural substrates for processing chemosensory information in snakes

Snakes interact with their chemical environment through their olfactory and vomeronasal systems. The present report summarizes advances on neural substrates for processing chemosensory information. First, the efferent and centrifugal afferent connections of the main and accessory olfactory bulbs were reinvestigated. Second, the afferent and efferent connections of the nucleus sphericus, the main target of the accessory olfactory bulb, were characterized. The nucleus sphericus gives rise to a very small projection to the hypothalamus, but it does project to other telencephalic structures where olfactory and vomeronasal information could converge. Third, the intra-amygdaloid circuitry and the amygdalo-hypothalamic projections were described. The medial amygdala, for instance, receives both vomeronasal and olfactory inputs and projects to the hypothalamus, namely, to the lateral posterior hypothalamic nucleus. Fourth, because the lateral posterior hypothalamic nucleus projects to the hypoglossal nucleus, the motor center controlling the tongue musculature, this projection could constitute a pathway for chemosensory information to influence tongue-flicking behavior. In summary, vomeronasal information is mostly relayed to the hypothalamus not via the nucleus sphericus but through other telencephalic structures. Convergence of olfactory and vomeronasal information appears to occur at different levels in the telencephalon. A neural substrate for the chemosensory control of tongue-flicking behavior is provided.