Biology and Biomechanics in Osteosynthesis of Proximal Humerus Fractures

Abstract Surgical treatment of proximal humeral fractures still remains a challenge. This is primarily due to the fact that sufficient implant fixation in humeral head fractures is often not achieved due to substantial bone tissue loss with increasing age. In the last few years the locking plates and locking nails have been introduced into clinical practice with varying results. The biomechanical studies have focused on locking plate osteosynthesis as well. The following paper focuses on bone quality, biomechanical studies and biology of proper osteosynthesis and reviews the most recent literature.     

The use of a new hydrophilic polymer, Kollicoat IR, in the formulation of solid dispersions of Itraconazole.

Kollicoat IR, a new pharmaceutical excipient developed as a coating polymer for instant release tablets, was evaluated as a carrier in solid dispersions of Itraconazole. The solid dispersions were prepared by hot stage extrusion. Modulated temperature differential scanning calorimetry and X-ray powder diffraction were used to evaluate the miscibility of the drug and the carrier. The pharmaceutical performance was evaluated by dissolution experiments, performed in simulated gastric fluid without pepsin (SGF(sp)). In the X-ray diffractograms no Itraconazole peaks were visible; the polymer on the other hand appeared to be semi-crystalline. Moreover, its crystallinity increased during the extrusion process due to exposure to heat and shear forces. Modulated temperature differential scanning calorimetry analysis showed that the drug and the polymer formed a two phase system. Separate clusters of glassy Itraconazole were present for drug loads of 40% or higher, indicating further phase separation. Dissolution measurements demonstrated a significantly increased dissolution rate for the solid dispersions compared to physical mixtures. Interestingly the physical mixture made up of glassy Itraconazole and Kollicoat IR (20/80, w/w) showed a dissolution rate and maximum that was much higher than that of the physical mixture made up of crystalline Itraconazole and that of pure glassy Itraconazole. The results of this study show that Kollicoat IR is a promising excipient for the formulation of solid dispersions of Itraconazole prepared by hot stage extrusion.     

Assessment of alcohol and other drug use behaviors in health professions students.

Alcohol and other drug (AOD) use behaviors of health professions students (HPS) were assessed by surveying both university-based HPS and other nursing programs in a Midwestern state in 1999. Response was 2,646 (56.4%) of surveyed students. Family history of alcohol-related and drug-related problems were reported by 39.8% and 13.9%, respectively, with 42.6% of respondents reporting one or both. Among nursing respondents, 48.1%, 19.2% and 51.1%, respectively, reported family problems with alcohol, drugs, or one or both. Past-year alcohol use was comparable to undergraduate college students (UCS) nationally (83%); heavy drinking, tobacco and recreational drug use by HPS were lower. Past year drug use was highest among medical students. Marijuana was the predominant illicit drug; medical students and males most often reported use. Health professions educational systems should proactively address student AOD prevention, education and assistance needs.     

Standardized quick en bloc technique for procurement of cadaveric liver grafts for pediatric liver transplantation

This paper describes a quick procedure for cadaveric liver graft retrieval during multiple organ harvesting. The technique is based on minimal preliminary dissection, absence of in situ direct portal perfusion, and en bloc removal of the liver and pancreas, with an aortic patch encompassing the coeliac trunk and superior mesenteric artery. The results of 110 pediatric liver transplantations with 109 organs harvested using this technique are reported. There were no graft harvesting injuries. The liver graft primary nonfunction rate was 4.5% (5/110). The 3-month retransplantation rate was 10%. The actual patient survival rates were 93% at 3 months and 90% at 1 year; actual graft survival rates were 85.5% and 78%, respectively. The technique described was at least as safe as conventional procedures. A major advantage of the procedure is its flexibility, which allows for the easily combined procurement of other organs (whole pancreas and intestine).     

The Problem of Intractability: The Continuing Need for New Medical Therapies in Epilepsy

Summary: Treatment of epilepsy, one of the most common neurologic disorders, has evolved from "institutional" poly-therapy to "dogmatic" monotherapy, and, most recently, to "rational" polypharmacy. The introduction of bromides for the treatment of epilepsy was followed first by phenobarbital and then by phenytoin as therapeutic options. Although attempts to combine medications were legion, none was supported by studies that demonstrated the benefit of such combinations. The issue of adverse effects became a principal argument in favor of monotherapy. Monotherapy, using newly developed drugs, avoided problems due to drug interactions but was ineffective in 20–30% of patients. A greater understanding of basic disease mechanisms and developments in molecular biology have led to an increased number of effective drugs for the estimated 6–12% of patients with epilepsy whose condition is intractable. Clinical research continues to build on the work of basic scientists in attempting to develop treatments based on a desire to move beyond the palliative and to affect the causative mechanisms of the disease. Novel medical approaches now under exploration include the use of drugs with complementary mechanisms of action, stimulation of various components of the nervous system, biochemical manipulations, focal intracerebral drug perfusion, and gene therapy.     

Inducible and constitutive expression of resistance to glycopeptides and vancomycin dependence in glycopeptide-resistant Enterococcus avium.

A clinical isolate of Enterococcus avium, Ea1, which exhibited inducible, low-level resistance to vancomycin and teicoplanin, and two mutants selected from this strain, Ea3 and Ea31, were studied. Ea3 was vancomycin dependent and derived from Ea1, while Ea31 was not vancomycin dependent, was constitutively resistant, and was derived from Ea3. Hybridization studies revealed that vanA was present in Ea1 and suggested that it was located on a high-molecular-weight plasmid. In the absence of induction, Ea1 synthesized only the natural UDP-MurNAc-pentapeptide precursor, and after induction it synthesized an additional precursor identified as UDP-MurNAc-tetrapeptide-D-lactate. The latter was the only precursor found in Ea3 and Ea31, even after precursor accumulation. From these results, we infer that (i) the low level of resistance to glycopeptides in strain Ea1 may be in part due to the residual synthesis of the normal precursor and (ii) the vancomycin dependence of mutant Ea3 could be due to the fact that this strain does not produce any peptidoglycan precursor in the absence of induction.