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Biomedical subjects

P R Stricker

Publications and source records attributed to P R Stricker.

8 recordsLinked to original sources
PubMed1998

Other ergogenic agents.

Amid the surrounding chaos of the supplement blitz, athlete, coach, and physician alike must step back and place the issue of supplements into perspective. There is no legal supplement that can substantially alter performance to date in the same way as illegal drugs. Effectiveness, safety, legality, and purity of compounds are all issues that should be addressed when approaching the use of any supplement. Education about the validity of the claims of supplements is important. Research is lending useful and helpful information despite the many new products continually appearing on the market. Because there is no mechanism for investigations to adequately research every supplement, many of the supplements should be approached with caution and skepticism. In addition, supplements in and of themselves should not be viewed as the sole answer to performance improvement. There is some promise to an extremely small number of supplements that appear to enhance performance, yet they do so in the realm of complete athletic training, including hard work, sports-specific training and strength training, psychological preparedness, and good nutritional intake.

Dietary Supplements↗
PubMed1998

Prospective evaluation of history and physical examination: variables to determine radiography in acute ankle injuries.

OBJECTIVE: This study investigated history and physical findings among 74 patients with acute ankle injuries in order to determine factors significantly associated with fractures, excluding avulsion fragments < 3 mm in size, and syndesmosis injuries and to determine factors that necessitate radiography. DESIGN: This was a prospective study performed during a 12-month period. After recording history and physical examination data, a gestalt prediction of a positive or negative radiographic result was made before the patient underwent ankle radiography. Analysis then determined factors important for radiography. PATIENTS AND SETTING: Patients who presented to a sports medicine center with an acute ankle injury were enrolled in the study after meeting the enrollment criteria. MAIN OUTCOME MEASURES: Before analysis, predictions for injury were based on accepted indicators. Outcome measures, factors that would indicate the need for radiography, were formulated after data collection and statistical analysis. RESULTS: Radiographic findings showed nine fractures and three widened syndesmoses as well as 15 minor ligamentous avulsions. Statistical analysis showed significant association (p < 0.05) of fracture with previous ankle fracture, syndesmosis pain with external rotation stress testing, and pain along the middle third of the distal fibula, from anterior to posterior. Syndesmosis injuries had a significant association with pain during external rotation stress testing. CONCLUSIONS: Although additional investigation with larger patient numbers would be beneficial, this study highlights the importance of history of previous fracture, pain on the distal mid-fibula or mid-tibia, and pain with external rotation. Furthermore, if these three variables are prospectively applied as criteria for radiography, a 55% reduction in radiography would result with 100% sensitivity. Finally, experienced sports medicine physicians had a 100% sensitivity, 68% specificity, 100% negative predictive value, and 39% positive predictive value for prediction of clinically significant fractures or syndesmosis injuries.

Acute Disease↗
PubMed1997

Pegylated peptides. V. Carboxy-terminal PEGylated analogs of growth hormone-releasing factor (GRF) display enhanced duration of biological activity in vivo.

In the present study, human growth hormone-releasing factor (hGRF) and analogs were successfully pegylated at the carboxy-terminus using a novel solid- and solution-phase strategy. Following synthesis, these pegylated hGRF analogs were evaluated for in vitro and in vivo biological activity. Specifically, hGRF (1-29)-NH2, [Ala15]-hGRF (1-29)-NH2, [desNH2Tyr1, D-Ala2, Ala15]-hGRF(1-29)-NH2 and [His1, Val2, Gln8, Ala15, Leu27]-hGRF(1-32)-OH were each C-terminally extended using a Gly-Gly-Cys-NH2 spacer (previously demonstrated not to alter intrinsic biological activity), and then monopegylated via coupling to an activated dithiopyridyl-PEG reagent. PEG moieties of 750, 2000, 5000 or 10,000 molecular weight (MW) were examined to determine the effect of polymer weight on activity. Initial biological evaluations in vitro revealed that all C-terminally pegylated hGRF analogs retained high growth hormone (GH)-releasing potencies, regardless of the MW of PEG polymer employed. Two of these pegylated hGRF analogs, [desNH2Tyr1, D-Ala2, Ala15]-hGRF (1-29)-Gly-Gly-Cys(NH2)-S-Nle-PEG5000 and [His1, Val2, Gln8, Ala15, Leu27]-hGRF(1-32)-Gly-Cys(NH2)-S-Nle-PEG5000, were subsequently evaluated in both pig and mouse models and found to be highly potent (in vivo potency range = 12-55-fold that of native hGRF). Relative to their non-pegylated counterparts, these two pegylated hGRF analogs exhibited enhanced duration of activity.

Animals↗
PubMed1993

Effects of growth hormone-releasing factor and(or) thyrotropin-releasing hormone on growth, feed efficiency, carcass characteristics, and blood hormones and metabolites in beef heifers.

The objective of this study was to determine the effect of long-term administration of a growth hormone (GH)-releasing factor analog (GRFa) and(or) thyrotropin-releasing hormone (TRH) on growth, feed efficiency, carcass characteristics, and blood hormones and metabolites in beef heifers. Crossbred heifers (n = 48; 345.9 +/- 2.8 kg) were divided into four equal groups: control (vehicle), 1 microgram of GRFa (human GRF 1-29 analog).kg BW-1.d-1, 1 microgram of TRH.kg BW-1.d-1, or GRFa + TRH. Daily s.c. injections continued for 86 d. Blood samples were collected from half of the heifers after injection on d 1, 36, and 78. On d 89, all heifers were slaughtered. Treatments did not affect (P > .05) ADG but GRFa + TRH decreased (P < .05) ADFI relative to all other treatments. Feed conversion efficiency tended (P < .10) to be improved in the groups given GRFa alone or TRH alone. Treatment with GRFa and(or) TRH did not affect carcass weight, dressing percentage, conformation score, backfat thickness, or weights of liver, kidneys, pituitary, and ovaries. The GRFa + TRH treatment reduced (P < .05) fat score and increased (P < .05) longissimus muscle area relative to other treatments. The GRFa treatments reduced (P < .05) the weight and fat percentage of the mammary gland and increased (P < .05) heart weight. Treatment with TRH alone failed to stimulate GH on d 1, 36, and 78. Treatment with GRFa alone increased (P < .05) GH above controls on d 36, whereas GRFa + TRH increased (P < .05) GH on d 1, 36, and 78. Treatment with GRFa alone increased (P < .05) IGF-I only on d 1, whereas GRFa + TRH was without effect on all days. Across sampling days, treatments had little effect on blood concentrations of insulin, triiodothyronine, nonesterified fatty acids, urea nitrogen, and glucose. The GRFa alone and GRFa + TRH decreased (P < .05) and TRH alone increased (P < .05) thyroxine concentrations. In conclusion, with the dose and administration regimen used, GRFa and(or) TRH yielded small but positive improvements in animal performance.

Animals↗
PubMed1993

An unusual presentation of liver laceration in a 13-yr-old football player.

Abdominal injury occurs infrequently from athletic trauma, yet when it does occur, it can be very serious. Although rupture of a major blood vessel can lead to rapid loss of blood, insidious blood loss can also result from apparently insignificant injury of the spleen, liver, or kidney and lead to delayed problems. Awareness of the potential for such injury is vital because outcome can be adversely affected by a low index of suspicion, and this can be compounded by the fact that the initial physical examination is not always a reliable indicator of the severity of injury. Classic reports of these injuries describe splenic injury from a left-sided blow and hepatic injury from right-sided trauma. We present a case report of liver laceration in a young football player not only to comment on its unusual mechanism and presentation, but also to illustrate the importance of rapid assessment and transport of the athlete with a serious abdominal injury to avoid the consequences of delayed diagnosis and treatment.

Adolescent↗