Conformation and hydrogen bonding of N-formylmethionyl peptides

Crystals of N-formyl-L-methionyl-L-phenylalanine (C₁₅H₂₀N₂O₄S). grown from aqueous methanol solution are orthorhombic, space group, P2₁2₁2₁, with cell parameters at 294K of a = 4.900(2), b = 17.947(4), c = 18.726(4)Å, V = 1646.8ų, M.W. = 324.4, Z = 4 and D_m= 1.308 g/cc, and as expected, all nearly identical to that of N-f-D-Met-D-Phe studied by Jeffs, Heald, Chodosh & Eggleston (Int. J. Peptide Protein Res. 24 , 442–446, 1984). The crystal structure was solved and refined using CAD-4 data (1095 reflections ≥ 3σ) to a final R value of 0.042. Molecules related by the a-translation form a parallel β-sheet rather than anti-parallel sheet as stated in the earlier study of Jeffs et al. The formation of the parallel rather than the anti-parallel p-sheet structure, the use of the C-H…O hydrogen bonds to stabilize the b-sheet and the very short O-H…O hydrogen bond between the carboxyl OH and the N-acyl oxygen atom emerge as the main structural features of the chemotactic N-formyl methionyl peptides.     

AEC Syndrome Caused by a Novel p63 Mutation and Demonstrating Erythroderma Followed by Extensive Depigmentation

Abstract:  We present an infant with AEC syndrome due to a novel TP63 mutation (F552S), who demonstrated neonatal erythroderma followed by extensive depigmentation. We are unaware of previous reports highlighting the extensive depigmentation present in our patient.     

Double-blind cross-over trial comparing beclomethasone dipropionate and terfenadine in perennial rhinitis

Eighteen patients with perennial rhinitis were evaluated in this double-blind cross-over trial comparing beclomethasone dipropionate (BDP) aqueous nasal spray with terfenadine tablets. Both treatments were effective in reducing symptom scores but BDP was significantly better than terfenadine in relieving running nose and sneezing ( P <0.05). BDP also had a greater effect on reducing nasal inflammation than terfenadine. Although the clinicians and patients assessed both therapies to be equieffective, significantly more patients preferred the BDP treatment ( P <0.003). Overall, BDP therapy proved more beneficial than terfenadine therapy in this small group of perennial rhinitis sufferers.     

Prophylactic blood transfusion in maternal sickle cell syndromes

Summary. An assessment of the benefits of prophylactic blood transfusion during 51 pregnancies in women with haemoglobin SS, haemoglobin SC and haemoglobin S-β-thalassaemia in a retrospective study from 1978 to 1984 has failed to demonstrate any clear conclusions as to their efficacy. Of the transfused patients, 22% developed atypical red cell antibodies and 14% had immediate minor transfusion reactions. Our data show no significant difference in fetal or maternal outcome between those patients who were transfused prophylactically and those who were not. A prospective study to clarify the appropriate place of this important aspect of management in women with sickle cell disease in pregnancy is suggested.     

Suppression of Post-vasectomy Cytotoxic Sperm Antibody Formation in Rats by a Short-term Pretreatment With Cyclosporine

ABSTRACT: The effect of a short pulse therapy with cyclosporine on the production of vasectomy-induced cytotoxic sperm antibodies was studied in Lewis rats. Cyclosporine at a dose of 10 mg/kg was administered once daily for 7 days before and 7 days after vasectomy (group A), for 7 days before vasectomy (group B), and for 7 days after vasectomy (group C). Ten rats were studied in each group for a period of 5 weeks. Ten rats were vasectomized and untreated with cyclosporine (group U). All animals in this group developed high titers of cytotoxic sperm antibodies at the end of the first week after vasectomy (primary antibody response). In contrast, all the treated rats of groups A, B, and C had a normal range of sperm antibody titers. By the third week, six of nine rats in the post-treated group C had significant cytotoxic sperm antibody titers, while the other groups had normal antibody titers. In the fourth week, all the rats of groups A and B continued to have normal sperm antibody titers of ≤16, while most animals in groups C (78%) and U (63%) had significant cytotoxic sperm antibody titers. It is concluded that prevasectomy treatment with cyclosporine may significantly reduce or delay the production of cytotoxic sperm antibodies in Lewis rats.     

Effects of Electrocautery on Transvenous Lead Insulation Materials

Introduction: Insulation defects are a leading cause of transvenous lead failure. The purpose of this study was to determine the effects of electrocautery on transvenous lead insulation materials.
Methods: A preparation was done to simulate dissection of a transvenous lead from tissues. Radiofrequency energy was delivered using a standard cautery blade at outputs of 10, 20, and 30 W, for 3 and 6 seconds, using parallel and perpendicular blade orientations on leads with outermost insulations of silicone rubber, polyurethane, and silicone–polyurethane copolymer. Damage to each lead segment was classified after visual and microscopic analysis.
Results: Significant insulation damage occurred to almost all polyurethane leads. Full insulation breaches were observed with 30 W regardless of application duration with a parallel direction and with all power outputs with a perpendicular direction. Thermal insulation damage to copolymer insulation was similar to that of the polyurethane leads. In contrast, there was no thermal damage to silicone leads, regardless of the power output and duration of power delivery. However, mechanical insulation damage was observed to all silicone leads when at least 20 W was applied in a direction perpendicular to the lead.
Conclusions: Polyurethane (PU55D) and copolymer materials have low thermal stability and are highly susceptible to thermal damage during cautery. Implanting physicians should be aware of the lead insulation materials being used during implant procedures and their properties. The use of direct contact cautery on transvenous leads should be minimized to avoid damage to the lead, especially on leads with polyurethane or copolymer outer insulations.     

Interpolating Unipolar Epicardial Potentials from Electrodes Separated by Increasing Distances

In cardiac mapping, potentials for unexplored areas are estimated by interpolating values from nearest neighbor electrodes regardless of distances between these sites or wave front orientation. The effects of these variables on interpolated unipolar electrograms were analyzed two ways: with a computer model and with electrograms recorded 9.9 and 14.1 mm apart. For the model, wave fronts (n = 39) were generated from electrograms recorded during right ventricular (RV) activation in five dogs following the RV isolation procedure. Each wave front was assumed to propagate radially at 0.5 m/sec from a site 30 mm from the center of a square array with electrodes located at the center and corners. Each wave front crossed the array with its tangent at an angle of 0 degrees, 45 degrees, or 90 degrees to the diagonal line connecting opposite corner electrodes. Potentials for all five sites were generated from each wave front and were interpolated for the center site from the generated corner potentials. Generated and interpolated center site potentials were compared using correlation coefficients (r) and percent root mean square differences (%RMSD). Mean r values fell below 0.90 for interelectrode distances of 15.6 mm, 2.8 mm, and 1.4 mm at 0 degrees, 45 degrees, and 90 degrees wave front orientations, respectively. For experimentally measured potentials recorded 9.9 mm apart, results from interpolated electrograms were similar to results from the model at 0 degrees propagation. Electrograms interpolated from potentials measured 14.1 mm apart had poorer r and %RMS values than those from the computer model. Thus, with linear interpolation unipolar electrograms can be inaccurately interpolated from electrodes less than 3 mm apart or correctly interpolated from electrodes more than 14 mm apart depending upon wave front orientation.