Delineation of the Role of Nicotinic Acetylcholine Receptor Genes in Alcohol Preference in Mice

The genetic factors that increase risk for alcohol and nicotine addiction have been elusive, although the frequent co-abuse of these drugs suggests they may act on a common biological pathway. A site of action for both nicotine and alcohol effects in the brain are neuronal nicotinic acetylcholine receptors (nAChR). This report explores the association between six nAChR subunit genes (Chrna3, Chrna4, Chrnb4, Chrnb2, Chrna5, and Chrna7) with alcohol preference (AP) using co-segregation of AP with nAChR subunit genotypes in a F₂ population produced from reciprocal crosses of alcohol-preferring C57BL/6J (B6) and alcohol-avoiding DBA/2J (D2) strains of mice. Polymorphisms located within the Chrna5-Chrna3-Chrnb4 cluster on mouse chromosome 9 were found to co-segregate with AP, with high-drinking F₂ mice carrying B6 alleles and low-drinking F₂ mice carrying D2 alleles. Further, the Chrnb4 and Chrna5 genes showed expression differences between B6 and D2 mice, which is compatible with their involvement in AP in mice and, potentially, alcohol abuse in humans.     

Does robotic assistance improve efficiency in performing complex minimally invasive surgical procedures?

Objective  

We used a model of biliary-enteric anastomosis to test whether da Vinci robotics improves performance on a complex minimally invasive surgical (MIS) procedure.     

Migration and HIV transmission in rural South India: an ethnographic study

There is a widespread assumption in Northern Karnataka, India that HIV transmission is due to the large volume of male seasonal labour out-migration. In order to examine this issue, an ethnographic study was conducted in one of the Northern Karnataka districts using a combination of quantitative and qualitative methods. Findings indicate that migration does not seem to be a key factor affecting sexual behaviour among married men. Nearly 35% of married migrant men reported being involved in extramarital sex and 40% of unmarried migrant men were involved in premarital sex. While earlier in the epidemic there was a strong correlation between HIV infection and migration, more recently the correlation seems to be getting weaker. More innovative HIV prevention programmes which take into account the social and cultural characteristics of this region are urgently needed to curtail the rapid development of the epidemic.     

The role of iNOS in alcohol-dependent hepatotoxicity and mitochondrial dysfunction in mice

Nitric oxide (NO) is now known to control both mitochondrial respiration and organelle biogenesis. Under conditions of ethanol-dependent hepatic dysfunction, steatosis is increased, and this is associated with increased expression of inducible nitric oxide synthase (iNOS). We have previously shown that after chronic exposure to ethanol, the sensitivity of mitochondrial respiration to inhibition by NO is enhanced, and we have proposed that this contributes to ethanol-dependent hypoxia. This study examines the role of iNOS in controlling the NO-dependent modification of mitochondrial function. Mitochondria were isolated from the livers of both wild-type (WT) and iNOS knockout (iNOS-/-) mice that were fed an isocaloric ethanol-containing diet for a period of 5 weeks. All animals that consumed ethanol showed some evidence of fatty liver; however, this was to a lesser extent in the iNOS-/- mice compared to controls. At this early stage in ethanol-dependent hepatic dysfunction, infiltration of inflammatory cells and the formation of nitrated proteins was also decreased in response to ethanol feeding in the iNOS-/- animals. Mitochondria isolated from wild-type ethanol-fed mice showed a significant decrease in respiratory control ratio and an increased sensitivity to NO-dependent inhibition of respiration relative to their pair-fed controls. In contrast, liver mitochondria isolated from iNOS-/- mice fed ethanol showed no change in the sensitivity to NO-dependent inhibition of respiration. In conclusion, the hepatic response to chronic alcohol-dependent cytotoxicity involves a change in mitochondrial function dependent on the induction of iNOS.     

Selective immunoglobulin A deficiency in Iranian blood donors: prevalence, laboratory and clinical findings

Selective deficiency of immunoglobulin A (IgA) is the most frequent primary hypogammaglobulinemia. As some IgA-deficient patients have IgA antibodies in their plasma which may cause anaphylactic reactions, blood centers usually maintain a list of IgA-deficient blood donors to prepare compatible blood components. In this study we determined the incidence of selective IgA deficiency (SIgAD) in normal adult Iranian population. 13022 normal Iranian blood donors were included in this study. The assay which we used was adapted to the manual pipetting system and ELISA reader was used for screening. Other classes of immunoglobulins (G, M), as well as secretory IgA and IgG subclasses were tested in IgA deficient cases by ELISA. SPSS was used for statistical analysis.Among 13022 studied cases, 11608 blood donors were males (89.14%) and 1414 were females (10.86%). Their mean (+/-SD) age and weight were 38.5+/-11 years and 82+/-12 Kg respectively. Twenty of the screened samples were found by means of ELISA to be IgA-deficient (less than 5mg/dl), (frequency; 1:651). The data could indicate a compensation for IgA deficiency by serum IgM in one of our IgA deficient cases (Patient 5). We observed a correlation between IgG3 and serum IgA in deficient cases (r=0.498, P=0.025). Our results indicate that in present study the prevalence of S IgA D is in agreement with data from other Caucasians populations (from 1:300 to 1:700). In conclusion, Selective IgA Deficiency could be almost asymptomatic in most cases in general population. Our study suggests that; due to high frequency of IgA deficiency in Iran, it seems necessary to measure IgA levels for every blood donor and blood recipient to find IgA deficient cases.     

Biological activity of nitric oxide in the plasmatic compartment

There exist reaction products of nitric oxide (NO) with blood that conserve its bioactivity and transduce an endocrine vasomotor function under certain conditions. Although S-nitrosated albumin has been considered the major species subserving this activity, recent data suggest that additional NO species, such as nitrite, nitrated lipids, N-nitrosamine, and iron-nitrosyl complexes, may contribute. We therefore examined the end products of NO reactions in plasma and blood in vitro and in vivo by using reductive chemiluminescent assays and electron paramagnetic resonance spectroscopy. We found that NO complexes in plasma previously considered to be S-nitrosated albumin were <10 nM after elimination of nitrite and were mercury-stable, consistent with iron-nitrosyl or N-nitrosamine complex. During clinical NO gas inhalation protocols or in vitro NO donor treatment of human plasma, S-nitroso-albumin did not form with NO exposure <2 microM, but plasma methemoglobin was detectable by paramagnetic resonance spectroscopy. Consistent with this formation of methemoglobin, human plasma was found to consume approximately 2 microM NO at a rate equivalent to that of hemoglobin. This NO consumption was mediated by the reaction of NO with plasma haptoglobin-hemoglobin complexes and limited slower reaction pathways required for S-nitrosation. These data suggest that high-affinity, metal-based reactions in plasma with the haptoglobin-hemoglobin complex modulate plasmatic NO reaction products and limit S-nitrosation at low NO flux. The studies further suggest that alternative NO reaction end products in plasma, such as nitrite, N-nitrosamines, iron-nitrosyls, and nitrated lipids, should be evaluated in blood NO transport along the vasculature.     

Activity-dependent inhibitory synapse remodeling through gephyrin phosphorylation

Maintaining a proper balance between excitation and inhibition is essential for the functioning of neuronal networks. However, little is known about the mechanisms through which excitatory activity can affect inhibitory synapse plasticity. Here we used tagged gephyrin, one of the main scaffolding proteins of the postsynaptic density at GABAergic synapses, to monitor the activity-dependent adaptation of perisomatic inhibitory synapses over prolonged periods of time in hippocampal slice cultures. We find that learning-related activity patterns known to induce N-methyl-d-aspartate (NMDA) receptor-dependent long-term potentiation and transient optogenetic activation of single neurons induce within hours a robust increase in the formation and size of gephyrin-tagged clusters at inhibitory synapses identified by correlated confocal electron microscopy. This inhibitory morphological plasticity was associated with an increase in spontaneous inhibitory activity but did not require activation of GABA_A receptors. Importantly, this activity-dependent inhibitory plasticity was prevented by pharmacological blockade of Ca²⁺/calmodulin-dependent protein kinase II (CaMKII), it was associated with an increased phosphorylation of gephyrin on a site targeted by CaMKII, and could be prevented or mimicked by gephyrin phospho-mutants for this site. These results reveal a homeostatic mechanism through which activity regulates the dynamics and function of perisomatic inhibitory synapses, and they identify a CaMKII-dependent phosphorylation site on gephyrin as critically important for this process.Several activity-dependent plasticity and homeostatic mechanisms (1, 2) contribute to regulate synaptic strength at excitatory synapses. Similar mechanisms are also expected to finely tune the level of inhibition in response to activity in individual neurons, but the mechanisms remain poorly understood. Different forms of plasticity at GABAergic synapses have been reported based on either presynaptic or postsynaptic mechanisms (3, 4). Similar to receptors at excitatory synapses, GABA_A receptors (GABA_ARs), which mediate the fast component of inhibitory transmission, display complex trafficking mechanisms that affect the surface localization and diffusion of receptors (5). The distribution and clustering of GABA_ARs at synapses is tightly regulated through interactions with the scaffolding protein gephyrin, one of the main structural constituent of inhibitory postsynaptic densities. Gephyrin forms multimeric complexes that allow the anchoring of GABA_ARs (6) via molecular mechanisms that include phosphorylation and interactions with the guanine-nucleotide exchange factor collybistin (7–12). In addition to changes in inhibitory strength, more recent in vivo experiments revealed that inhibitory synapses are also dynamic structures that can be formed and eliminated in response to sensory experience (13–15). The mechanisms implicated in the coordinated regulation of excitatory and inhibitory plasticity remain, however, poorly understood. We investigated here this issue by using repetitive confocal imaging of tagged gephyrin to monitor the dynamic behavior of perisomatic inhibitory synapses over periods of days. Our results show that induction of synaptic plasticity and neuronal activity induces the formation of newly formed inhibitory synapses through postsynaptic mechanisms involving the phosphorylation of gephyrin at a CaMKII-dependent site.     

Novel technique for airless connection of artificial heart to vascular conduits

Successful implantation of a total artificial heart relies on multiple standardized procedures, primarily the resection of the native heart, and exacting preparation of the atrial and vascular conduits for pump implant and activation. Achieving secure pump connections to inflow/outflow conduits is critical to a successful outcome. During the connection process, however, air may be introduced into the circulation, traveling to the brain and multiple organs. Such air emboli block blood flow to these areas and are detrimental to long-term survival. A correctly managed pump-to-conduit connection prevents air from collecting in the pump and conduits. To further optimize pump-connection techniques, we have developed a novel connecting sleeve that enables airless connection of the Cleveland Clinic continuous-flow total artificial heart (CFTAH) to the conduits. In this brief report, we describe the connecting sleeve design and our initial results from two acute in vivo implantations using a scaled-down version of the CFTAH.