Israel Medical Association Journal

Polyubiquitylation of cellular proteins has long been recognized as a prelude to a degradative fate in proteasomes. In recent years, however, ubiquitin conjugation has emerged as a regulatory strategy of considerable versatility. Most notably, monoubiquitylation is attributed an intimate role in trafficking of membrane proteins between various cellular compartments. Diverse classes of transmembrane proteins from across the eukaryotic spectrum (e.g., epidermal growth factor-receptor and other receptor tyrosine kinases) become modified with monoubiquitin molecules. Monoubiquitylation of substrates, in turn, regulates both their endocytosis at the plasma membrane and sorting in endosomes for delivery to lysosomes or vacuoles. A mechanistic rationale lies in the identification of a growing list of ubiquitin-binding domains carried by a variety of endocytic adaptor proteins. Thus, ubiquitin-conjugated membrane proteins may form extensive contacts with the endocytic machinery. Further, ubiquitin-binding adaptors and other endocytic components are, likewise, often monoubiquitylated. In this case, ubiquitin conjugation may serve to enhance intermolecular avidity in cargo-bound endocytic complexes, or alternatively, to mediate timely inactivation of ubiquitin-binding adaptors. Interestingly, the ubiquitin/endocytosis interface is appropriated by pathogenic organisms, for instance, during budding of viruses from host-infected cells. Moreover, compromised ubiquitin-mediated transport of certain signaling receptors is associated with disease states, including oncogenic transformation.

Three decades have elapsed since the inception of Level I trauma centers as the final link in the trauma system "chain of survival".

The human placenta is the interface between the mother and fetus in the uterus. Until recently it was generally believed that the uterus provides a protective environment for the fetus. It is now accepted that any chemical substance, including any therapeutic agent, administered to a mother is able to permeate across the placental barrier. Unfortunately, the placental transfer of substances and their distribution in the placenta is not well established. Understanding the structure of placental transporters and their function may serve as the ideal tool for drug development and the cure of mother and fetus during pregnancy.
 

Background: Israel lacks a systematic surveillance of sports injuries, and knowledge of risk factors and specific patterns of injury is inadequate. In order to promote prevention of sports-related injuries, the magnitude of the problem must first be identified and the incidence and severity of sports injuries described.

Objective: To conduct a survey on previous sports injuries among a sample of Israeli athletes.

Methods: A convenience sample of Israeli amateur athletes participating in the 1997 15th Maccabiah Games was randomly selected. The study group answered an anonymous self-administered questionnaire that included sociodemographic data, and information regarding their sports activity and sports-related injuries that had occurred during the previous 2 years.

Results: The study group, aged 12-3 years (median age 21), comprised 301 consenting athletes in 28 different sports. Of these athletes 56.1% reported having had at least one injury. Most injuries (75.6%) involved the upper and lower extremities, and 37.8% of the injured sportsmen had received medical attention from a physician. Half of the athletes participated in contact sports - both collision and limited impact. This group had a much greater proportion of reported injuries in all age groups.

Conclusion: Surveillance of sports injuries should be expanded in order to develop appropriate prevention programs in Israel.