Effects of propofol on the human heart electrical system: a transesophageal pacing electrophysiologic study

Previous studies have shown that infusion of propofol has sometimes been associated with bradyarrhythmias. To evaluate the effects of propofol on the electrical system of the heart, we carried out an electrophysiologic study with transesophageal pacing on ten healthy subjects scheduled for minor elective maxillo–facial surgery. By means of atrial pacing conducted by a progressive increase in stimulation cycles, we determined, in awake patients and during propofol anesthesia (2.5 mg kg^-1 for induction, followed by 100 μg kg^-1 min^-1 for maintenance), the correct sinus recovery time and the eventual appearance of Wenckebach atrio–ventricular block. We did not notice sinoatrial node depression or pathologic increase in the atrio–ventricular conduction.     

Study of the HLA system in the Haitian population

The HLA-A and HLA-B phenotypes of 329 unrelated Haitian adults were determined and gene and haplotype frequencies were estimated. A summary of the data is presented together with a brief comparison with American Black, American White, and African Black populations. HLA gene and haplotype frequencies of Haitians are quite similar to those for American Blacks. The frequency of Aw34 appears to be smaller in Haitians than in American and African Blacks. No statistically significant differences were found in the frequencies of B-locus antigens.     

Detection of Sperm Surface Related Antibodies by Indirect Immunofluorescence Test on Sperm Suspensions. Indirect I FT on Sperm Suspensions

An indirect immunofluorescence test (IIFT) using sperm suspensions was carried out on 20 sera with sperm agglutinins (SA) and on 25 negative controls. IIFT gave results highly correlated with the occurrence of sperm agglutinating activity. Moreover, a relation was found among class of Ig involved in IF reactivity, fluorescent stain pattern and type of sperm agglutinations. In all sera with "mixed" or "tail-tail" sperm agglutinating activity, IgG were involved in IF reactivity; the fluorescent stain constantly appeared in a granular pattern along the sperm tail and most often on the head surface too. In relation to high titres of "head-head" sperm agglutinating activity, IgM were involved in IF reactivity; here the fluorescent stain appeared to be localized on acrosomal surface. The results indicate that indirect IFT on sperm suspensions specifically detects sperm surface related antibodies.     

Allergic reactions to ampicillin. Studies on the specificity and selectivity in subjects with immediate reactions

Background and Objective Ainpicillin (AMP) is a drug that has been prescribed extensively. Reactions that have been reported include exanthema. desquamative contact eczema, urticaria and anaphylaxis. Experimental evidence indicates that the side chain of AMP is a structure that may induce a selective immune response either at the humoral or lymphocyte T-cell level. With regard to IgE reactions, the selectivity and specificity of the response needs to be studied in humans. Objective To study tbe specificity of tbe IgE response in a group of subjects who had an immediate allergic reaction after the administration of AMP. Methods Subjects developing an immediate response (anapbylaxis or urticaria) after the administration of AMP or an aminopenicillin derivative witb the same side chain as AMP were studied. Skin tests were made to determinants generated from benzyl penicillin (BP): benzyl penicilloyl (BPO) and minor determinant mixture (MDM), as well as amoxicillin (AX) and AMP. Specific IgE antibodies were determined to benzyl penicilloyl polylisine (BPO-PLL), amoxicilloyl-polyllsine (AX-PLL) and ampicilloyl-polylisine (AMPPLL). The specificity of the IgE antibody response was studied by RAST and RAST inbibition. Subjects were classified in three categories: group A: those who were skin test and/or RAST positive to determinants derived from benzylpenicllin, group B: those who were negative to determinants derived from benzylpenicillin but were skin lest and/or RAST positive to determinants derived from AX and AMP and group C: those who were exclusively positive to determinants derived from AMP. Results A total of 48 subjects was included in the study. In group A there were 35 cases, in group B 10 cases, and in group C tbree cases. RAST inhibition studies showed that in some instances tbe side chain of AMP could induce specific responses with a variable degree of crossreactivity between BP and AX. Conclusions Atbough AMP can induce an immediate IgE response in subjects allergic to betalactams and tbe structure of the side chain may contribute to the specificity of the response, our results indicate tbat in most instances crossreactivity with the other penicillins exists and that in the groups studied selective reactions to just AMP derived determinants were uncommon.     

Decrease in Patient Radiation Exposure by a Tantalum Filter during Electrophysiological Procedures

Aim: Minimization of X-ray exposure remains a primary issue in cardiac electrophysiology. The effectiveness of X-ray beam filtration during cardiac electrophysiological procedures was therefore studied, using a 0.05-mm-thick tantalum (Ta) foil, as a filter on the primary X-ray beam, to reduce the patient dose without degradation of image quality.
Method: Preliminary tests were made on a phantom developed with polymethylmethacrylate, catheters, and guide wires. The filter was then used in patients during cardiac procedures. Identical patient images were obtained with and without the Ta filter insertion and the ratio between image quality and patient dose was evaluated. Changes in patient dose and signal-to-noise ratio, as image quality index were measured on the phantom and in patients.
Results and Conclusions: When the Ta filter was used, the mean effective individual patient dose decreased by 3 to 40% (mean reduction = 27%), with no perceivable difference in image quality estimated by electrophysiologists. This Ta filter may be useful to limit the radiation exposure of patients and operators during cardiac procedures.