The interference of distal humeral plating with the medial and lateral collateral ligaments of the elbow

Introduction

The aim of the present study was to determine the anatomical relationship and evaluate the potential interference of today’s common distal humerus plates with the medial and lateral collateral ligaments of the elbow.

Materials and methods

The elbow joints of 23 embalmed upper extremities were dissected. Three different brands of distal humerus double-plating systems were applied in a standardized fashion. We used a caliper to measure the amount of absolute overlap of the plates on the corresponding collateral ligaments.

Results

The data show contact and overlap with the medial and lateral collateral ligaments in all tested medial and lateral plates. The posterolateral and posteromedial plates showed no contact with the ligaments, yet they did contact the posterior joint capsules. The medial plates showed less contact/overlap when compared with the lateral and extended medial plates.

Conclusion

Based on the present data, we conclude that distal humerus plating using the perpendicular technique with standard-sized medial plates shows the least amount of overlap over the medial and lateral collateral ligaments. The extent of the overlap of the ligaments by the humeral plates is clearly shown in the present study.     

Strategies for assessing the implications of malformed frogs for environmental health

The recent increase in the incidence of deformities among natural frog populations has raised concern about the state of the environment and the possible impact of unidentified causative agents on the health of wildlife and human populations. An open workshop on Strategies for Assessing the Implications of Malformed Frogs for Environmental Health was convened on 4-5 December 1997 at the National Institute of Environmental Health Sciences in Research Triangle Park, North Carolina. The purpose of the workshop was to share information among a multidisciplinary group with scientific interest and responsibility for human and environmental health at the federal and state level. Discussions highlighted possible causes and recent findings directly related to frog deformities and provided insight into problems and strategies applicable to continuing investigation in several areas. Possible causes of the deformities were evaluated in terms of diagnostics performed on field amphibians, biologic mechanisms that can lead to the types of malformations observed, and parallel laboratory and field studies. Hydrogeochemistry must be more integrated into environmental toxicology because of the pivotal role of the aquatic environment and the importance of fates and transport relative to any potential exposure. There is no indication of whether there may be a human health factor associated with the deformities. However, the possibility that causal agents may be waterborne indicates a need to identify the relevant factors and establish the relationship between environmental and human health in terms of hazard assessment.     

Human adipocytes secrete mineralocorticoid-releasing factors

Obesity has become an epidemic problem in western societies, contributing to metabolic diseases, hypertension, and cardiovascular disease. Overweight and obesity are frequently associated with increased plasma levels of aldosterone. Recent evidence suggests that human fat is a highly active endocrine tissue. Therefore, we tested the hypothesis that adipocyte secretory products directly stimulate adrenocortical aldosterone secretion. Secretory products from isolated human adipocytes strongly stimulated steroidogenesis in human adrenocortical cells (NCI-H295R) with a predominant effect on mineralocorticoid secretion. Aldosterone secretion increased 7-fold during 24 h of incubation. This stimulation was comparable to maximal stimulation of these cells with forskolin (2 x 10(-5) M). On the molecular level, there was a 10-fold increase in the expression of steroid acute regulatory peptide mRNA. This effect was independent of adipose angiotensin II as revealed by the stimulatory effect of fat cell-conditioned medium even in the presence of the angiotensin type 1 receptor antagonist, valsartan. None of the recently defined adipocytokines accounted for the effect. Mineralocorticoid-stimulating activity was heat sensitive and could be blunted by heating fat cell-conditioned medium to 99 degrees C. Centrifugal filtration based on molecular mass revealed at least two releasing factors: a heat sensitive fraction (molecular mass >50 kDa) representing 60% of total activity, and an inactive fraction (molecular mass <50 kDa). However, the recovery rate increased to 92% when combining these two fractions, indicating the interaction of at least two factors. In conclusion, human adipocytes secrete potent mineralocorticoid-releasing factors, suggesting a direct link between obesity and hypertension.     

Microbiology's principle of biofilms as a major factor in the pathogenesis of acne vulgaris

Propionibacterium acnes reside within the pilosebaceous unit in a biofilm. As such, they live in a community of bacteria that encase themselves within an extracellular polysaccharide lining, which the organisms secrete after adherence to the surface. This gylcocalyx polymer acts as a protective exoskeleton and serves as a physical barrier, limiting effective antimicrobial concentrations within the biofilm microenvironment. The gylcocalyx polymer secreted by P. acnes as a biofilm may explain the immunogenicity of the organism as well as the clinical course of the disease. The P. acnes' biofilm model explains many aspects of acne pathogenesis and therapy, including why prolonged antibiotic treatment is needed, why antibiotic resistance is not a reliable assessment of treatment outcome, why accutane offers long-lasting effectiveness, and why benzoyl peroxide radicals are beneficial. This microbiologic principle of biofilms as applied to acne leads to numerous new pathways of assessment and exploration.     

The relationship of superior labralanteroposterior (SLAP) lesions and pseudolaxity to shoulder injuries in the overhead athlete

Understanding the effect of superior labral lesions on the function of the shoulder is essential to successfullytreating the overhead athlete. Recognizing the pseudolaxity owing to superior labral anteroposterior (SLAP) lesions and the pathological "peel-back" sign is critical in evaluating the injured shoulder in general and repairing the SLAP lesion in particular. The mechanical characteristics of suture anchors are more favorable than tacks in resisting the pathological forces responsible for the peel-back mechanism. The higher success rate of arthroscopic suture anchor repair of SLAP lesions in comparison with open capsulolabral reconstruction suggests that SLAP lesions are the usual cause of the "dead arm" syndrome. In our experience, arthroscopic repair of SLAP lesions can return the overhead athlete to their preoperative level of function in the vast majority of cases (87% return to preoperative level for two or more seasons).