The recovery of α-adrenoceptor function and binding sites after phenoxybenzamine

Summary The recovery of peripheral -adrenoceptor function and binding sites was studied in male New Zealand white rabbits after treatment with the irreversible adrenoceptor antagonist phenoxybenzamine. Phenoxybenzamine (5 mg/kg) was administered intravenously and the animals studied 30 min to 12 days later. Pressor dose response curves to intravenous phenylephrine, noradrenaline and guanabenz were constructed in vivo in conscious animals. The contractile response of abdominal aorta and renal artery to phenylephrine and noradrenaline was examined in vitro and the recovery of specific prazosin and clonidine binding to spleen membranes investigated in radioligand binding studies.The half life (t _1/2) for recovery of maximum pressor response in vivo ranged from 0.9±0.2 days for phenylephrine to 1.4±0.1 days for guanabenz. The t _1/2 for recovery of ED₅₀ was not significantly different to t _1/2 for recovery of maximum pressor response and ranged from 0.8±0.2 days for noradrenaline to 1.3±0.3 days for phenylephrine.Half life for recovery of maximum response and EC₅₀ in the isolated tissues was similar to that obtained in vivo for recovery of pressor responses and ranged from 0.4±0.1 days for the EC₅₀ of noradrenaline in the renal artery to 1.2±0.6 days for maximum response to phenylephrine in the abdominal aorta.The rate of recovery of specific clonidine binding did not differ significantly from the rate of recovery of pressor responses to the ₂-selective agonist guanabenz. t _1/2 for maximum number of specific clonidine binding sites, B _max was 1.6±0.9 days. However t _1/2 for recovery of specific prazosin binding was significantly longer than recovery of responses to phenylephrine and noradrenaline, t _1/2 for B _max was 3.6 ±0.1 day.     

Quality of life outcomes after minimally invasive repair of pectus excavatum utilizing a new set of metallic bars and stabilizers

Background/PurposeThe aim of the study was to evaluate the postoperative quality of life (QoL) of patients who underwent minimally invasive repair of pectus excavatum (MIRPE) with a newly designed bar and bar stabilizers.MethodsWe conducted a prospective randomized study in which patients were operated either with standard perpendicular stabilizers (control group) or with the newly designed oblique stabilizers (intervention group). All patients were evaluated 6 months after the operation with the Pectus Excavatum Evaluation Questionnaire (PEEQ).ResultsThere were 16 patients in the control group and 14 in the intervention group. Mean age was 17 (SD: 3.3, range 14–27) years. There were no demographic differences between groups. Two patients in the control group and one in the intervention group were repaired with two bars instead of one. There was one reoperation in each group. There was a significant difference between the pre- and postoperative scores, in both groups, in the patient body image domain (control group: 9.5 to 3; p < 0.01; intervention group 10 to 3; p < 0.01), as well as in the psychosocial domain (control group: 13.5 to 24, p < 0.01; intervention group: 15 to 24, p < 0.01). With regards to the patients' perception of physical difficulties before and after MIRPE, the difference between pre- and postoperative scores was greater in the intervention group (8 to 12, p < 0.01) than in the control group (10 to 11, p = 0.04). The mean length of stay was 4.5 and 5 days in the intervention group and the control group, respectively.ConclusionOur study showed that patients who underwent MIRPE with the newly designed bars and stabilizers had non-inferior outcomes than patients reported in the literature who underwent MIRPE with standard bars and stabilizers. We found slightly better outcomes in patients in the intervention group compared to the control group, but larger studies will be needed to confirm if those differences are statistically significant.Level of evidenceII     

Heart Transplantation for Giant Cell Myocarditis: A Case Series

BackgroundGiant cell myocarditis (GCM) has a poor prognosis without heart transplant, but post-transplant survival is unknown.PurposeTo describe the post-transplant survival of patients with GCM at a large transplant center.MethodsSeven patients underwent heart transplant for histologically confirmed GCM of the explanted heart. The median age was 59 years, and 43% (3 of 7) were female. All patients had cardiogenic shock, multiorgan failure, elevated troponin, and recurrent ventricular tachycardia, and some required mechanical circulatory support. All patients received rabbit antithymocyte globulin (rATG) in the perioperative period at a dose of 1.5 mg/kg daily for 1 to 5 days and 4 received intravenous immunoglobulin 1 g/kg daily for 2 days after rATG. All patients had early initiation of tacrolimus by first to third postoperative day depending on renal function, early mycophenolate, and high dose steroid. All were maintained using tacrolimus, mycophenolate, and prednisone.ResultsOne patient had asymptomatic recurrence of GCM at 3 months, managed by up-titration of tacrolimus, and had asymptomatic 2R cellular rejection at 4 months, managed with steroid bolus. No patient had high-grade rejection. One patient died at 267 days, possibly of GCM. Six of 7 (86%) remain alive at a median of 842 days (2.3 years) post transplant.ConclusionsPatients with GCM have excellent post-transplant survival with use of rATG and triple drug immunosuppressive therapy; however, some patients remain at risk for GCM recurrence after transplant, which may respond to augmented immunosuppression.     

Sun Exposure,Tanning Behaviors,and Sunburn: Examining Activities Associated With Harmful Ultraviolet Radiation Exposures in College Students

Journal of Prevention - Understanding the behaviors that lead to sunburn is an important objective toward developing intervention strategies to reduce risk for skin cancers. Our cross-sectional...     

A more realistic approach to the cumulative pregnancy rate after in-vitro fertilization

As most studies overestimate the cumulative pregnancy rate,a method is proposed to estimate a more realistic cumulativepregnancy rate by taking into account the reasons for an earlycessation of treatment with in-vitro fertilization (IVF). Threemethods for calculating cumulative pregnancy rates were compared.The first method assumed that those who stopped treatment hadno chance at all of pregnancy. The second method, the one usedmost often, assumed the same probability of pregnancy for thosewho stopped as for those who continued. The third method assumedthat only those who stopped treatment, because of a medicalindication, had no chance at all of pregnancy and that the otherswho stopped had the same probability of pregnancy as those whocontinued treatment Data were used from 616 women treated atthe University Hospital Nijmegen, Nijmegen, The Netherlands.The cumulative pregnancy rates after five initiated IVF cyclesfor the three calculation methods were in the ranges 37–51%for the positive pregnancy test result, 33–55% for a clinicalpregnancy and 30–56% for an ongoing pregnancy. As expected,the first method underestimated the cumulative pregnancy rateand the second overestimated it The third method produced themost realistic cumulative pregnancy rates.     

Re‐evaluation of normative electronystagmography data in healthy ageing

Previous work by our group questions the validity of existing electronystagmography ( eng ) reference ranges in the elderly. We aim to establish valid reference ranges for eng in people over 65 on the Nicolet Nystar Plus system. Ninety‐six healthy asymptomatic subjects over 65 underwent eng , including spontaneous and positional nystagmus, saccades, smooth pursuit, optokinetic nystagmus and bithermal calorics; 95% reference ranges with confidence intervals were calculated. The newly determined reference ranges were far wider than those provided by the eng equipment manufacturer for eight out of 11 parameters (all P < 0.001). Vestibular function is known to deteriorate and become more variable with age. The failure to reflect this change in currently used reference ranges may have contributed to the high rates of vestibular disease reported in some series of dizzy elderly patients. Clinical interpretation of eng depends on valid reference ranges.