An epidemiologic survey of the literature on high school football injuries revealed methodologic problems. These numerator-denominator inconsistencies and other confounding factors are discussed. The authors suggest a more reliable system of reporting these parameters to further reduce the risk of high school football injuries.

Adolescent↗

PubMedDate not supplied

High school football injuries: identifying the risk factors.

This epidemiologic survey of the literature on the factors contributing to the high number of high school football injuries consolidates the current information on the characteristics and risk factors associated with these injuries. To reduce the incidence of knee sprains and strains, the most common injuries to this population, the following preventive recommendations are presented: 1) optimum maintenance of playing fields; 2) use of the soccer-style shoe; 3) noncontact and controlled activities in practice sessions; and 4) increased vigilance over technique during injury-prone preseason practices. The authors conclude that more research into factors such as exposure time and activity at injury will further reduce the risk to the high school football player.

Adolescent↗

PubMedDate not supplied

Characterization and evaluation of detoxification functions of a nontumorigenic immortalized porcine hepatocyte cell line (HepLiu).

Primary porcine hepatocytes (PPH) are currently used in research and therapeutic applications as the biological component of extracorporeal liver assist devices to overcome the shortage of human hepatocytes. However, their finite life span and typically rapid loss of functions limit their utility. An immortalized, nontumorigenic, highly differentiated porcine hepatocyte cell line was developed in our laboratory to resolve these disadvantages. PPH were transfected with simian virus 40 (SV40) T antigen under the control of the SV40 early promoter. From the established 69 clones, 23 clones displaying hepatocyte-like morphology were screened for diazepam metabolism. One clone, HepLiu D63, has been maintained in culture for > 2 years, through more than 60 passages and 240 divisions. Albumin protein, present in early passages, was lost at later passages, but albumin transcript still was detectable in later passages. Carbamoyl phosphate synthetase, a gateway enzyme of the urea cycle, was consistently detectable in HepLiu cells. Cytokeratin 18, a characteristic marker of primary hepatocytes, was detected by both immunofluorescent staining and Western blot in HepLiu cells. Furthermore, maintenance of P450 functions in HepLiu cells was evidenced by diazepam and 7-ethoxycoumarin metabolites measured by HPLC. Phase II conjugative function was measured as acetaminophen glucuronidation. P450 dealkylase was demonstrated microscopically by the conversion of a nonfluorescent substrate to a fluorescent product. Both Northern blot analysis and immunofluorescent staining showed SV40 T antigen expression in the nuclei of HepLiu cells. No tumor formation occurred when HepLiu cells were injected into severe combined immunodeficient (SCID) mice nor was the TAI (a tumor marker) mRNA expressed, even in later passages. This immortalized, nontumorigenic, highly functional cell line may provide a valuable tool for drug/toxicological studies, liver biologic regulation studies, and artificial liver support systems.

Animals↗

PubMedDate not supplied

MR appearance of acquired spinal epidermoid tumors.

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Adult↗