Participation in clinical drug studies: motivations and barriers.

Drugs must be tested in human clinical trials before they can be approved for marketing in the United States. These trials are often conducted by contract research organizations (CROs) that offer financial incentives to those who participate. The objectives of this study were to identify the motivations and barriers to participation in clinical drug studies. A survey was distributed to individuals at a CRO, who were either completing participation or were being screened for participation in a clinical drug study, and to a sample of university students. Responses were obtained from 195 people who participated and 68 people who considered participating in a clinical drug study. The motivations for participating were financial compensation, improvement of health, and contribution to science. Those who considered participating opted not to because of schedule conflicts, the risk involved, or potential discomfort from the medical procedures or medication.

Effects of exogenous porcine somatotropin on the carcass composition, hormonal and metabolic profiles, lipogenic capacity, and binding of insulin to erythrocyte receptors of fast- versus slow-growing swine.

Twenty barrows were designated as fast-growing (FG) and their littermates designated as slow-growing (SG) based on birth, weaning, and 56-d weight. Half of each group received 70 micrograms of porcine somatotropin (pST)/kg BW daily beginning at 40 kg BW. At 60 and 105 kg BW, blood was collected every .5 h for 12 h beginning 1 h before pST injection, fat biopsies were taken for in vitro lipogenic activity, and insulin erythrocytes were isolated for receptor binding. Swine treated with pST had elevated ADG (.95 vs .88 kg/d; P < .1) and reduced days to slaughter (61 vs 67; P < .1). The pST-treated pigs had less average backfat (2.73 vs 3.96 cm; P < .01), larger longissimus muscle areas (32.3 vs 28.2 cm2; P < .05), and a higher percentage of muscle (56.3 vs 50.3%; P < .01) than control pigs. Exogenous pST increased protein (17.4 vs 13.2%; P < .05) and decreased fat (22.9 vs 37.1%; P < .05). The FG pigs had higher ADG (.98 vs .86 kg/d; P < .01) and required fewer days to slaughter (57 vs 71; P < .01) than SG pigs. Administration of pST increased (P < .01) average pST levels (1.7 vs 14.0 ng/mL) in FG and SG pigs at 60 kg BW. At 105 kg BW, pST was higher (P < .01) in pST-FG than in pST-SG swine (46.0 vs 19.3 ng/mL) but was not different between FG and SG control swine (1.9 vs 1.8 ng/mL). Administration of pST increased concentrations of IGF-I (510.0 vs 160.0 ng/mL) and nonesterified fatty acids (182 vs 109 muEq/L, P < .01) in FG and SG swine. Over sample periods and growth rates, pST reduced (P < .05) CO2 production and lipid synthesis (.345 and 1.85 vs .575 and 2.71 mumol of glucose incorporated.g-1.2 h-1). At 60 kg BW, FG swine had less (P < .01) CO2 production and lipid synthesis (.299 and 1.83 vs .921 and 3.61 mumol.g-1.2 h-1) than did SG swine. Exogenous pST increased (P < .05) binding to insulin erythrocyte receptors (7.25 vs 6.34%).

Long-term local effects of intraosseous infusion on tibial bone marrow in the weanling pig model.

The weanling pig model was used to determine the long-term local effects, if any, on tibial bone marrow after intraosseous (IO) infusion of resuscitation fluid and drugs at standard dosages. One of six IO treatments (two normal saline boluses [20 mL/kg]; bolus sodium bicarbonate [1 mEq/kg]; 10% sodium bicarbonate infusion at a maintenance rate for 1 hour; bolus 1:10,000 epinephrine [0.01 mg/kg]; 1:10,000 epinephrine solution infusion, 1 microgram/kg/min for 1 hour; or dopamine infusion, 10 micrograms/kg/min for 1 hour) was randomly administered via the left tibia to 18 pigs at 4 weeks of age. The animals were subsequently followed for 3 months, after which marrow from the same space and peripheral blood were examined. Marrow from the right tibia of each animal served as control; untreated historic controls were also used for comparison. Examination of the marrow revealed normal cell differentials in all limbs in all groups. Overall cellularity was somewhat decreased in the experimental limbs of the normal saline bolus group when compared with same-animal control limbs, perhaps due to the pressure effect from rapid injection. Peripheral blood counts and differentials in these and all other animals were normal. The authors conclude that IO administration of commonly used resuscitative medications does not result in significant adverse effects in the tibial bone marrow in this model.

Restoration of wrist extension after paralysis.

Loss of active extension of the wrist is a major functional handicap for the affected patient. Restoration of wrist extension, primarily accomplished via tendon transfers, is a fundamental part of surgical treatment after paralysis. The anatomy and physiology of the wrist, the clinical aspects, the history, and restorative treatment of wrist extension after paralysis are discussed.

Enhancement of ovulation rate in gilts by increasing dietary energy and administering insulin during follicular growth.

Two experiments were conducted to examine influences of dietary energy and insulin on ovulation rate and patterns of luteinizing hormone (LH), follicle stimulating hormone (FSH), glucose, insulin and estradiol in gilts during 6 d before estrus. In Exp. 1, 36 gilts were given altrenogest for 14 d to synchronize estrus. In a factorial arrangement, gilts were fed one of two levels of dietary energy (5,771 or 9,960 kcal metabolizable energy (ME)/d), and given one of two levels of porcine insulin (0 or .1 IU/kg body weight iv every 6 h). Dietary treatments began 4 d before and insulin treatments began 1 d after the last day of altrenogest, respectively, and lasted until 24 h after estrus. Main effect means for number of corpora lutea were 14.0 +/- 1.3 and 17.6 +/- .9 for 5,771 and 9,960 kcal ME (P less than .05), and 14.6 +/- 1.0 and 17.0 +/- .9 for 0 and .1 IU insulin (P less than .05). Number of LH peaks on d 3 was greater for gilts that received 9,960 kcal than 5,771 kcal (3.3 +/- .2 vs 2.7 +/- .2; P less than .05), and for .1 than 0 IU insulin (3.2 +/- .2 vs 2.7 +/- .2; P less than .05). During the first 24 h of sampling, concentrations of LH and FSH were greater (P less than .05) in gilts receiving 9,960 kcal ME plus insulin than for other treatment combinations. Concentrations of estradiol were not affected by treatments. In Exp. 2, two formulations of insulin were evaluated for influence on ovulation rate. All gilts received altrenogest and 9,960 kcal ME/d as in Exp. 1. Then on the first day after altrenogest, seven gilts each received short-acting insulin (as in Exp. 1), long-acting insulin (zinc suspension, 1.0 IU/kg body weight every 18 to 24 h), or served as controls. Ovulation rates were increased (P less than .05) by both insulin preparations (15.6, control; 19.1, short-acting; 18.5, long-acting; SE = 1.2). Concentrations of LH tended to be greater after short-acting insulin, but differences were not significant (P = .13). We conclude that increases in ovulation rate produced by dietary energy and insulin are not necessarily accompanied by changes in gonadotropins or estradiol.

Circulating androgen levels in the developing boar.

Circulating levels of serum androgens were studied for 11 Duroc boars. Jugular blood samples were collected at 2-wk intervals, beginning at 5 wk of age and continuing until 27 wk of age. Testosterone and androstenedione values were determined by radioimmunoassay. Analysis of variance indicated a significant difference among ages in testosterone and androstenedione concentrations. Plasma levels of testosterone were 1.5 to 1.9 ng/ml at 5 to 7 wk, decreased to 0.3 to 0.6 ng/ml between 7 and 17 wk, and then increased to 3.7 ng/ml by the 27th wk of age. Plasma androstenedione tended to be elevated during the 5th through 7th wk (3.5 to 4.9 ng/ml), decreased to 0.9 to 1.6 ng/ml through the 19th wk and then gradually increased through the 27th wk (1.4 to 2.4 ng/ml). A highly significant correlation was observed between testosterone and androstenedione (r=0.39). Testicular volume was shown to be highly correlated with testosterone concentration (r=0.48). During the early life of the pig, the predominant androgen is androstenedione with testosterone becoming the predominant androgen as the boar reaches maturity.

Sample design and estimation procedures for a national health examination survey of children.

The Health Examination Survey is one of the major survey programs employed by the National Center for Health Statistics to obtain information about the health status of the U.S. population. It is a part of the National Health Survey, authorized in 1956 by the 84th Congress as a continuing Public Health Service activity. The National Health Survey employs three different survey programs to accomplish its objectives. One of these is the Health Interview Survey in which persons are asked to give in-formation related to their health or to the health of other household members. The second program, Health Resources, obtains health data and health resource and utilization information through surveys of hospitals, nursing homes, and other resident institutions and through the entire range of personnel in the health occupations. The third major program is the Health Examination Survey (HES), The Health Examination Survey collects data from samples of the civilian, noninstitutional population of the United States and, by means of medical and dental examinations and various tests and measurements, undertakes to characterize the population under study. This is the most accurate way to obtain diagnostic data on the prevalence of certain medically defined illnesses. It is the only way to obtain information on unrecognized and undiagnosed conditions-in some cases, even nonsymptomatic conditions. It is also the only way presently available to obtain distributions of the population by a variety of physical, physiological, and psychological measurements. Although the sample is designed primarily to estimate the prevalence of specified health and health-related conditions in the population, the design also makes possible the study of relationships of the examination findings to one another and to certain demographic and socioeconomic factors.