Cellular and molecular effects of trimethyltin and triethyltin: Relevance to organotin neurotoxicity

Many of the neurotoxic aspects of organotin exposure have been described. Organotin exposure culminates in its accumulation in the CNS and PNS. The clinical picture is dominated by neurological disturbances; yet, the primary basis for their neurotoxicity is unknown. Trimethyltin (TMT) is primarily a CNS neurotoxin affecting neurons within the hippocampal pyramidal band and the fascia dentata. Triethyltin (TET) is a neurotoxin that produces a pathological picture dominated by brain and spinal cord edema. The first part of this review summarizes the current understanding of the interaction of TMT and TET with biologically active sites in the induction of neurotoxicity. In the second part, several hypotheses for the differential neurotoxic effects of these organotins and their shortcomings are discussed.     

Growth hormone effects on hypertrophic scar formation: a randomized controlled trial of 62 burned children

The hypercatabolism after massive pediatric burns has been effectively treated with recombinant human growth hormone, an anabolic agent that stimulates protein synthesis and abrogates growth arrest. While experimental studies have shown increased potential for fibrosis induced by growth hormone therapy, adverse effects on human scars have not been investigated. Our aim was to evaluate hypertrophic scar formation in 62 patients randomized to receive injections of 0.05 mg/kg/day of recombinant human growth hormone or placebo, from discharge until 1 year after burn. Scar scales were used to evaluate scar-severity at discharge, 6, 9, 12, and 18-24 months after burn, by three observers blinded to treatment. Computer-assisted planimetry allowed quantification of percentage of hypertrophic scar formation. Types I and III collagens were localized and quantified in scars and normal skin of patients from both groups, using immunohistochemistry with confocal laser microscopy analysis. Insulin-like growth factor-1 blood levels helped assess compliance. Statistical analysis showed that scar hypertrophy significantly increased from 6 to 12 months after injury in both groups, while decreasing at 18-24 months postburn. Types I and III collagens were statistically increased in the reticular layer of scars from both groups when compared to paired normal skin. Insulin-like growth factor-1 was significantly increased in the recombinant human growth factor-treated group. No differences were seen when recombinant human growth factor and control groups were compared using the scar scales, planimetry, or immunohistochemistry. We concluded that recombinant human growth hormone therapy did not adversely affect scar formation and should not contraindicate the administration of recombinant human growth hormone as a therapeutic approach to severely burned children.     

Vascular Access for Therapeutic Plasma Exchange

Abstract: Adequate venous access is an essential component of therapeutic plasma exchange (TPEX). The simplest kind of venous access is venipuncture of antecubital veins, but this technique may be limited by venous size or scarring following the procedure, requiring the placement of a specialized vascular access device (VAD). VADs provide reliable central venous access and may remain in place for several weeks or months, depending on the VAD and the venous site chosen. Their use, however, is potentially limited by the risk of complications. We discuss indications for insertion, choice of catheter and access site, and complications of VAD placement for TPEX.     

Accidental Occupational Farm Fatalities in North Carolina: 1984 to 1988

Development of interventions to prevent accidental occupational fatalities requires the prior identification of those at risk and the circumstances surrounding the injuries. A survey of unintentional farm fatalities was conducted using medical examiner reports (RIME) and death certificates (MECD) to identify deaths due to agricultural occupational injuries in North Carolina from 1984 through 1988. Of 393 cases, 123 met the criteria "farmer" listed as occupation on the RIME/MECD and/or "victim" in a rural area performing a farming task when injured. A second aim of this study was to use an existing data base to achieve maximum accuracy in identifying true cases of work-related farm fatalities.
A fatality rate of 41/100,000 agricultural workers was found; the National Institutes of Occupational Safety and Health's National Traumatic Occupational Fatality study criteria would have identified only 57 percent of these. Victims were characterized as middle age (53 years), white (76%), male (100%), full-time farmers (65%). Injury occurred during harvest season on Monday or Tuesday (47%) between 2 and 6 p.m. (54%). Death was pronounced at the scene (74%), with probable cause listed as tractor (62%). Injury location and land elevation were also related, with the mountain region having twice the fatality rate as the coastal plains region.     

Validity in hermeneutic phenomenological inquiry: towards an ethics of evaluation.

This article explores the relationship of ethics to validity in hermeneutic phenomenological inquiry. First, the authors present a brief overview of the various discourses on validity in qualitative research that have been variously applied to hermeneutic phenomenological inquiry. Next, they examine how relational ethics is a presence to bear within this form of inquiry. Finally, they offer a set of ethical reflections to help the researcher engage in a process of ethical questioning during each step of the research process.