Cortical thickness mediates the relationship between DRD2 C957T polymorphism and executive function across the adult lifespan.

Dopamine (DA) signaling is critical for optimal cognitive performance. Aging is accompanied by a change in the strength of this signaling, with a loss of striatal and extrastriatal D2 binding potential. The reduction in dopamine modulation with age negatively influences various aspects of cognition. DRD2 C957T (rs6277) impacts DA D2 receptor density and availability, with C homozygotes linked to lower striatal DA availability and reduced executive functioning (EF), but also high extrastriatal binding potential. Here, we investigated in 176 participants aged 20-94 years whether: (1) DRD2 C carriers differ from T carriers in cortical thickness or subcortical volume in areas of high concentrations of D2 receptors that receive projections from mesocortical or nigrostriatal dopaminergic pathways; (2) whether the DRD2*COMT relationship has any synergistic effects on cortical thickness; (3) whether the effect of DRD2 on brain structure depends upon age; and (4) whether DRD2-related regional thinning affects executive function performance. We show that DRD2 impacts cortical thickness in the superior parietal lobule, precuneus, and anterior cingulate (marginal after FDR correction), while statistically controlling sex, age, and COMT genotype. Specifically, C homozygotes demonstrated thinner cortices than both heterozygotes and/or T homozygotes in an age-invariant manner. Additionally, DRD2 predicted executive function performance via cortical thickness. The results highlight that genetic influences on dopamine availability impact cognitive performance via the contribution of brain structure in cortical regions influenced by DRD2.

Frontoparietal cortical thickness mediates the effect of COMT Val158Met polymorphism on age-associated executive function.

Proper dopamine (DA) signaling is likely necessary for maintaining optimal cognitive performance as we age, particularly in prefrontal-parietal networks and in fronto-striatal networks. Thus, reduced DA availability is a salient risk factor for accelerated cognitive aging. A common polymorphism that affects DA D1 receptor dopamine availability, COMT Val158Met (rs4680), influences enzymatic breakdown of DA, with COMT Val carriers having a 3- to 4-fold reduction in synaptic DA compared to COMT Met carriers. Furthermore, dopamine receptors and postsynaptic availability are drastically reduced with aging, as is executive function performance that ostensibly relies on these pathways. Here, we investigated in 176 individuals aged 20-94 years whether: (1) COMT Val carriers differ from their Met counterparts in thickness of regional cortices receiving D1 receptor pathways: prefrontal, parietal, cingulate cortices; (2) this gene-brain association differs across the adult lifespan; and (3) COMT-related regional thinning evidences cognitive consequences. We found that COMT Val carriers evidenced thinner cortex in prefrontal, parietal, and posterior cingulate cortices than COMT Met carriers and this effect was not age-dependent. Further, we demonstrate that thickness of these regions significantly mediates the effect of COMT genotype on an executive function composite measure. These results suggest that poorer executive function performance is due partly to thinner association cortex in dopaminergic-rich regions, and particularly so in individuals who are genetically predisposed to lower postsynaptic dopamine availability, regardless of age.

Laparoscopic cholecystectomy: consensus conference-based guidelines.

INTRODUCTION: Laparoscopic cholecystectomy (LC) is the gold standard technique for gallbladder diseases in both acute and elective surgery. Nevertheless, reports from national surveys still seem to represent some doubts regarding its diffusion. There is neither a wide consensus on its indications nor on its possible related morbidity. On the other hand, more than 25 years have passed since the introduction of LC, and we have all witnessed the exponential growth of knowledge, skill and technology that has followed it. In 1995, the EAES published its consensus statement on laparoscopic cholecystectomy in which seven main questions were answered, according to the available evidence. During the following 20 years, there have been several additional guidelines on LC, mainly focused on some particular aspect, such as emergency or concomitant biliary tract surgery. METHODS: In 2012, several Italian surgical societies decided to revisit the clinical recommendations for the role of laparoscopy in the treatment of gallbladder diseases in adults, to update and supplement the existing guidelines with recommendations that reflect what is known and what constitutes good practice concerning LC.

[Surgical management of schwannoma of biliary tract]. / Trattamento chirurgico di schwannoma della via biliare.

A borderline Schwann cell tumour with common bile duct compression and jaundice is extremely rare. This paper presents the first report in the Italian literature of a hepatojejunostomy for a symptomatic lesion midway between benign and malignant.

[Surgical treatment of fecal incontinence secondary to obstetric trauma]. / Surgical treatment of fecal incontinence secondary to obstetric trauma.

Fecal incontinence (FI) is associated to elevated costs related to diagnostic work-up, surgical treatment and instrumental follow-up. The real incidence is unknown and prevalence is higher after 45 years with a ratio F:M ratio of 8:1. Frequently FI is due to pelvic damage secondary to obstetric trauma. The Authors analyze surgical treatment results of FI secondary to obstetric trauma evaluating pathogenesis and instrumental diagnostic preoperative work-up. In case of muscular injury, "overlapping" of external sphincter represents the treatment of choice allowing a good medium long term results. In the treatment of patients with more complex injures or after overlapping failures, direct sphincteroplasty are indicated. After multiple surgical failures, or in case of pure neural damage, sacral nerve stimulation, graciloplasty or artificial anal sphincter may be offered by referral centers.