Diluted povidone-iodine irrigation prior to wound closure in primary and revision total joint arthroplasty of hip and knee: a review of the evidence.

Periprosthetic Joint Infection (PJI) of the Hip and of the Knee is a tremendous complication associated with high patient morbidity, cost, and increased health care resource utilization. Over the last few years, several perioperative strategies have been developed in the hopes of reducing the risk of early superficial and deep surgical site infection (SSI). One of the most performed intraoperative treatments to reduce the risk of SSI in total joint arthroplasty is the use of dilute povidone-iodine (DPI) irrigation prior to wound closure. For this reason, we believed a systematic review of the literature was needed to better understand the current literature on the efficacy of dilute betadine in reducing PJI. The search terms for this systematic review was performed for keywords "betadine", "povidone-iodine", "lavage", "irrigation" and "arthroplasty". A total of six studies were included, four of these reported the outcome of primary total joint arthroplasty, and two of these reported the outcome of revision total joint arthroplasty. Some studies reported that the use of DPI is effective to reduce the incidence of infective complications, meanwhile other studies did not find differences when DPI was used. More studies must be addressed to provide the efficacy of DPI irrigation.

Endocannabinoid system in first trimester placenta: low FAAH and high CB1 expression characterize spontaneous miscarriage.

Anandamide (AEA) and 2-arachidonoylglycerol (2-AG) were the first endocannabinoids to be characterized, that bind two G protein-coupled receptors, CB1 and CB2. AEA synthesized by multiple pathways, including NAPE-specific phospholipase D (NAPE-PLD) and degraded by the fatty acid amide hydrolase (FAAH). AEA levels are critical in regulating embryo development and the "window" of implantation. We examined the expression of nape-pld mRNA, CB1 and FAAH in human placenta hypothesizing that their altered signaling may contribute to spontaneous miscarriage. First trimester placentas from women with spontaneous miscarriage (group 1) were matched with placentas from women who underwent termination (group 2). Nape-pld expression was analyzed by RT-PCR; CB1 and FAAH expression by Western blot and immunohistochemistry. Nape-pld mRNA expression was higher in group 2 than in group 1. Western blot analysis revealed higher CB1 expression and lower or absent FAAH in group 1 than in group 2. Immunohistochemistry confirmed CB1 and FAAH signals in group 1 and group 2 placentas, respectively. Human placenta contains the enzymes to synthesize AEA. Moreover, placental tissue represents a target for endocannabinoids whose activity may regulate pregnancy outcome. In particular, very low or absent FAAH and high CB1 levels correspond with spontaneous miscarriage.

A synthetic fiber-reinforced stentless heart valve.

There is strong evidence that failure of bioprosthetic and synthetic valves occurs as a consequence of high tensile and bending stresses, acting on the leaflets during opening and closing. In stented prostheses, whether synthetic or biological, the absence of contraction of the aortic base causes the leaflets to be subjected to an unphysiological degree of flexure, which is also related to calcification. However, a stentless synthetic valve, which has a flexible aorta base, can be a good alternative for stented synthetic valves. Moreover, fiber-reinforcement is assumed to lead to a decrease of tears and perforation as a result of reduced stresses in the weaker parts of the leaflets in their closed configuration. The manufacturing method for a stentless, fiber-reinforced, synthetic valve is presented. Prototypes are tested in a pulse duplicator system. The results show that the mean systolic pressure difference is very low, while the high regurgitation (up to 26%) is probably caused by a too small coaptation area of the leaflets.

A three-dimensional mechanical analysis of a stentless fibre-reinforced aortic valve prosthesis.

Failure of bioprosthetic and synthetic three-leaflet valves has been shown to occur as a consequence of high tensile and bending stresses, acting on the leaflets during opening and closing. Moreover, in the stented prostheses, whether synthetic or biological, the absence of contraction of the aortic base, due to the rigid stent, causes the leaflets to be subjected to an unphysiological degree of flexure, which is related to calcification. It is shown that the absence of the stent, which gives a flexible aortic base and leaflet attachment, and leaflet fibre-reinforcement result in reduced stresses in the weaker parts of the leaflets in their closed configuration. It is postulated that this leads to a decrease of tears and perforations, which may result in a improved long-term behaviour. The effect of a flexible leaflet attachment and aortic base of a synthetic valve is investigated with a finite element model. Different fibre-reinforced structures are analysed with respect to the stresses that are likely to contribute to the failure of fibre-reinforced prostheses and compared with the results obtained for a stented prosthesis. Results show that for the stentless models a reduction of stresses up to 75% is obtained with respect to stented models with the same type of reinforcement.

A three-dimensional analysis of a fibre-reinforced aortic valve prosthesis.

Failure of synthetic heart valves is usually caused by tearing and calcification of the leaflets. It is postulated that leaflet fibre-reinforcement leads to a decrease of tears and perforations as a result of reduced stresses in the weaker parts of the leaflets. A three-dimensional finite element model of a reinforced three-leaflet valve prosthesis was developed to analyse the stress reduction. Different fibre reinforcements were investigated and the model responses were analysed for stresses that are expected to contribute to failure of fibre-reinforced valve prostheses. Results of these simulations show that, in peak stress areas of reinforced models, up to 60% of the maximum principal stresses is taken over by fibres and that, in some cases of reinforcement, a more homogeneous stress distribution is obtained.

Functional hyperthermia due to central dopaminergic impairment.

The clinical cases described are characterized by rigidity, mutism and hyperthermia, with cutaneous pallor and diaphoresis. This symptomatology marks the "malignant neuroleptic syndrome" and can be found, at times, in parkinsonians on "drug holiday". The cases described, which comprehend patients with both disorders, lead us to a single pathogenetic hypothesis: a central dopaminergic impairment. Hyperthermia, secondary to functional hypothalamic deficiency, is maintained by defective heat dispersion due to the lack of cutaneous vasodilation.