Assessment of body composition in the prader-willi syndrome using bioelectrical impedance

The accurate assessment of body composition is of importance in the Prader-Willi syndrome. Many techniques are not applicable due to ethical or practical reasons. However, the bioelectrical impedance technique is a rapid, painless, noninvasive method of estimating total body water and hence, fat-free mass in obese children and adolescents. We have compared estimates of total body water derived from bioelectrical impedance with actual measurements taken, using H₂¹⁸O dilution, in 14 children with Prader-Willi syndrome. Existing equations for predicting total body water from impedance showed a bias to underestimate actual measures of body water. There were positive correlations between the degree of underestimation with age and body fatness. It is possible that changes in body shapes influence bioelectrical impedance measurements in obese individuals, and that a prediction equation based upon a normal population will not be applicable to obese individuals. © 1992 Wiley-Liss, Inc.     

Marked Q-T prolongation due to encainide therapy

Summary Encainide is a type Ic antiarrhythmie agent. During encainide therapy, mild Q-T interval prolongation can be seen, usually associated with prolongation of the Q-R-S interval. The present case report describes an unusual and marked prolongation of the Q-T interval with no Q-R-S interval prolongation in a patient who was treated with encainide for atrioventricular nodal reentrant tachycardia. The drug metabolite profile in this patient's serum indicated an unusual elevation of the 3-methoxy-O-demethyl encainide metabolite, versus O-demethyl encainide. This elevated metabolite level suggests that 3-methoxy-O-demethyl encainide has a significant effect on prolongation of repolarization. An abnormal metabolism of encainide may be the underlying mechanism by which some patients would manifest an unusual prolongation of Q-T interval during encainide therapy.     

Reduced tumorigenicity of rodent tumour cells and tumour explants following infection with wild type and mutant herpes simplex virus, bovine mammillitis virus and encephalomyocarditis virus

The tumorigenicity of neoplastic hamster and mouse cell lines and tumour explants was reduced by infection with herpes simplex virus (HSV-1), a thymidine-kinaseless mutant of herpes simplex virus, namely 'MDK', encephalomyocarditis virus (EMC) and bovine mammillitis virus (BMV). There was an approximate relationship between duration of virus infection in vitro and reduction in incidence and/or rate of tumour development. The rate of tumour development was also reduced by 'site inoculation' of virus (HSV-1) at various time intervals following inoculation of tumorigenic BHK 21 cells indicating that virus was capable of reducing the rate of tumour development in a situation where the neoplastic cells were already transplanted into the susceptible host species. It is suggested that the therapeutic role of wild type, mutant or recombinant viruses merits further exploration towards prevention and treatment of human cancer.     

Development of a new wound dressing with antimicrobial delivery capability

A bilaminar wound dressing composed of an outer membrane and an inner three-dimensional matrix of a fabric or a sponge may be considered to constitute an ideal structure that promotes wound healing: the outer membrane prevents body fluid loss, controls water evaporation, and protects the wound surface from bacterial invasion, and the inner matrix encourages adherence by tissue growth into the matrix. Using this concept, we developed a biosynthetic wound dressing with a drug delivery capability. This medicated wound dressing is composed of a spongy sheet of a chitosane derivative and collagen mixture that is laminated to an antimicrobial-impregnated polyurethane membrane. In this study, a gentamycin sulfate-impregnated wound dressing was prepared and evaluated. The antimicrobial efficacy of this wound dressing was examined on an agar plate seeded with Pseudomonas aeruginosa. Also, the cytotoxicity of an antimicrobial released from this wound dressing was examined in an in vitro system with cultured skin substitutes. Both in vitro tests have shown that this wound dressing is capable of suppressing bacterial growth and minimizing cellular damage. In addition, in the treatment of wounds inflicted on rats and rabbits, this wound dressing was shown to be efficacious in covering full-thickness and split-thickness skin defects. Finally, the efficacy of this wound dressing was evaluated in a nonrandomized open-label study of 31 clinical cases. In 31 cases treated with this wound dressing, good or excellent wound healing was achieved.     

Oxygenator exhaust capnography: a method of estimating arterial carbon dioxide tension during cardiopulmonary bypass.

An in vivo study was undertaken during hypothermic (28 degrees C) cardiopulmonary bypass to compare oxygenator exhaust capnography as a means of estimating arterial carbon dioxide tension (PaCO2) with bench blood gas analysis. A total of 123 pairs of measurements were made in 40 patients. Oxygenator exhaust capnographic measurements systematically underestimated PaCO2 measured by a bench blood gas analyzer. During the cooling and stable hypothermic phases of cardiopulmonary bypass, the relationship was reasonably accurate, but became far more variable during rewarming. Oxygenator exhaust capnography could be used as an inexpensive means of continuously monitoring PaCO2 during the cooling and stable hypothermic phases of cardiopulmonary bypass but should not be used during rewarming.