Student perspectives on primary care preceptorships: enhancing the medical student preceptorship learning environment.

BACKGROUND: Medical students participate in a longitudinal (3-year) primary care preceptorship to assist them in developing skills in interviewing and examining patients in an ambulatory care setting. PURPOSE: To identify from a student's perspective important context and process issues in a longitudinal preceptorship. METHODS: The investigators used an "editing" style of analysis to identify significant themes across 24 medical student focus groups held between October 1995 and December 1997. RESULTS: Significant themes emerged from the data analysis that describe important features of what makes the preceptorship work for students. The main themes are active teaching, active learning, a trusting relationship, sufficient time, and a shared understanding of preceptorship objectives. The potential benefits to students in an enhanced learning environment are comfort, confidence, responsibility, skills, knowledge, reinforcement, learning opportunities, teaching opportunities, and models for practice. CONCLUSIONS: We offer recommendations for enhancing longitudinal preceptorships for preceptors, students, and leaders in medical education.

Evaluation of the duration of sperm fertilizing ability in five lines of commercial broiler breeder and Delaware cross males.

The ability to characterize the reproductive potential of male fowl can be affected by a number of factors, including age, type, insemination scheme, and number of sperm inseminated. Fertility is a complex interaction of traits involving two individuals of differing genetic composition: In modern broiler breeders, selected predominantly for growth and carcass characteristics, fertility problems may be exacerbated. In order to evaluate the male components of fertility, an experiment investigating the effects of male line on both average fertility and the duration of fertility was completed. Male chicks from five commercial broiler breeder male lines or sired by subfertile Delaware cross roosters were reared to adulthood. Between 30 and 60 wk of age, semen was collected from five males per line, extended and used to inseminate each of 10 to 12 hens from four broiler breeder female lines or Single Comb White Leghorn hens with 80 x 10(6) live sperm. Following a single insemination eggs were collected for 21 d and fertility determined by visual inspection following 4 d incubation. The percentages of live sperm and overall fertility data for the replicate trials were analyzed, following transformation, with a linear model and daily fertility data were analyzed by iterative least squares regression. Whereas there were large differences in fertility among individual males (durations from 3.4 to 14.5 d) within a line, there were no significant male line or replicate effects on overall fertility or the duration of fertility. However, there was a significant (P < 0.05) line-dependent reduction in the percentage of live sperm in broiler breeder males, with the subfertile Delaware cross males being intermediate. There were no significant female line or replicate effects on the duration of fertility; however, there were significant female line effects on overall fertility at both 7 and 21 d. These data suggest that although individual males varied widely, there were no male line effects on the duration of fertility in the lines of broiler breeders evaluated when analyzed by iterative least squares. Furthermore, these data suggest that although females may have significant affects on overall fertility, the duration of fertility appears to be a predominantly male characteristic. Therefore, iterative least squares regression may be a useful tool for identifying males with superior sperm fertilizing ability.

Determination of testis temperature rhythms and effects of constant light on testicular function in the domestic fowl (Gallus domesticus).

There is a wide range of opinions regarding the operating temperature of the testis in the domestic fowl. We used physiological monitoring techniques to investigate testis and body temperature over daily periods and under various light regimes to elucidate body temperature gradients in the fowl. We confirm that the operating temperature of the adult fowl's testes is equivalent to core body temperature (40-41 degrees C). Long-term continuous temperature monitoring showed that there was no difference between the temperature of the testis, liver, and peritoneum during a 24-h period either in a normal light:dark cycle or under constant light conditions. However, there was a slight decrease in all temperatures at subjective night in each case, a decrease that does not appear to be sufficient to influence spermatogenesis. Birds maintained under constant light throughout two cycles of the seminiferous epithelium (28 days) still exhibited normal testis function and structure, even when "nightly" testis temperature decrease was the lowest. Thus, by undergoing spermatogenesis at an elevated temperature, the domestic fowl system is unique among the homeothermic animal systems studied to date.

Independent and simultaneous unilateral occlusion of the pulmonary artery and extra-pulmonary primary bronchus in broilers.

Acutely tightening a snare around one pulmonary artery previously was shown to trigger a reversible ventilation-perfusion (V/Q) mismatch in broilers, as reflected by decreases in the partial pressure of oxygen in arterial blood (hypoxemia), accompanied by increases in the hydrogen ion concentration (acidosis) and partial pressure of carbon dioxide (hypercapnia). In the present study, snares were loosely implanted around the right pulmonary artery and the right extrapulmonary primary bronchus in anesthetized male broilers. These snares were tightened and released independently and then simultaneously to evaluate the possibility that directing the entire respiratory minute volume toward the left lung might attenuate the V/Q mismatch caused by forcing the entire cardiac output (CO) through the left lung. Fully reversible arterial blood hypoxemia, acidosis, and hypercapnia occurred when either snare was tightened independently. Presumably, tightening the bronchial snare restricted ventilation but not blood flow to the right lung, thereby permitting blood to perfuse poorly ventilated gas exchange surfaces. Simultaneously tightening both snares triggered arterial blood hypoxemia, acidosis, and hypercapnia similar to or greater in magnitude than the responses obtained by tightening the pulmonary artery snare independently. Tightening either snare independently or both snares simultaneously caused pulmonary arterial pressure to increase (pulmonary hypertension), and permanent obstruction of one bronchus in a separate experiment caused an increase in the right:total ventricular weight ratio, which is indicative of chronic pulmonary hypertension. The mean systemic arterial pressure decreased when the pulmonary artery snare was tightened independently or in combination with the bronchial snare, but not when the bronchial snare was tightened independently. The respiratory rate increased and the heart rate decreased when the pulmonary artery snare was tightened independently, but not when the bronchial snare was tightened independently or in combination with the pulmonary artery snare. These results demonstrate that the V/Q mismatch caused by forcing all the CO to perfuse one lung cannot be attenuated by simultaneously directing the entire respiratory minute volume toward the same lung.

Subconjunctival versus intrascleral mitomycin-C in trabeculectomy.

BACKGROUND AND OBJECTIVE: A randomized prospective comparison of sub-Tenon's administration of mitomycin-C (MMC) with intrascleral administration of MMC in trabeculectomy was performed to determine whether intrascleral application is superior to the standard sub-Tenon's application. PATIENTS AND METHODS: Twenty-four eyes of 23 patients were randomized to treatment with MMC (0.27 mg/ml for 5 minutes). The route of administration was subconjunctival in group A and intrascleral in group B. Preoperative and postoperative visual acuity (VA), intraocular pressure (IOP), number of medications, and complications were compared between the two groups. RESULTS: There was no statistically significant difference between the two groups preoperatively regarding VA, IOP, and number of medications. Postoperatively, IOP and number of medications required had decreased significantly in both groups. A significantly larger number of postoperative procedures were required in group B to control IOP (group A = 3, group B = 14, P = .002). CONCLUSION: Both methods of MMC application significantly decreased the IOP and the number of medicines required to control IOP after trabeculectomy. The intrascleral use of MMC resulted in the need for more surgery postoperatively (P = .002).

Vocalization and physiological response of pigs during castration with or without a local anesthetic.

The objectives of this project were to see whether heart rate, respiration rate, blood pressure, and vocalization could be used to evaluate stress of castration in pigs. Six groups of pigs 1, 2, 4, 8, 16, and 24 d of age were used in the study, a total of 172 pigs. Half of each group of pigs received lidocaine before castration, injected subcutaneously over the testicle and infiltrated around the cord; the other half were left as controls. Pigs castrated without lidocaine had a higher heart rate (P < .02) and higher frequency of highest energy (HEF) measurements of vocalization (P < .05). Incising the scrotum and severing the spermatic cord elicited the greater heart rate response (P < .05) to castration without anesthetic, whereas HEF was lower during cutting of the cord. Both the heart rate and HEF data suggest that castration without anesthetic is of greater stress for pigs 8 d of age or older. Respiration rate was not a viable measure of stress associated with castration.

A comparison of the investment in hospital-based obstetrical ultrasound in Wales and Washington state.

The purpose of this study was to examine differences in the way Britain and the United States invest in and deploy a new medical technology. We used structured interviews to obtain information on the technical sophistication and approximate replacement value of all hospital-based obstetrical ultrasound machines in every maternity hospital in Washington state and Wales. The supply of hospital-based ultrasound machines--approximately two machines per 1,000 births--was similar in both countries. Wales had fewer advanced ultrasound machines than Washington state, and they were based exclusively in high-volume district general hospitals; there were no obstetric ultrasound machines in the private sector. In Washington state, the majority of advanced machines were in small and medium-sized hospitals, and many private offices had ultrasound machines. The approximate replacement value of hospital-based machines was three times as high per birth in Washington state as in Wales. In the case of obstetrical ultrasound, centralization of facilities, a relatively small private sector, and global budgeting lead to lower expenditures per patient within the National Health Service without compromising access to care.

The diffusion of obstetric technology into rural U.S. hospitals.

We determined the distribution and sophistication of obstetric technologies in all 80 maternity hospitals in the state of Washington and examined the effect of rural or urban location, birth volume, and physician staffing on technological intensity. Although smaller and more rural hospitals refer most premature and low-birth-weight infants to regional referral centers, sophisticated prenatal and intrapartum technologies are available in the majority of even the smallest and most remote rural units. Rural hospitals have slightly lower obstetrical intervention rates than do their urban counterparts, but the differences are not great.

A surgical method to repair leaking filtering blebs.

Surgical revision of a chronically-thinned filtering bleb with a leak at the limbus is described. After surgical excision of the scarred cystic conjunctiva and Tenon's fascia surrounding the leaking bleb, relatively uninvolved conjunctiva and Tenon's fascia are mobilized with the help of a large relaxing incision in the superior fornix and sutured over the area of filtration. We have used this technique successfully in five cases to provide fresh tissue to repair the bleb leak and restore adequate filtration.

Measurements of peripapillary nerve fiber layer contour in glaucoma.

We developed a method to quantify the surface contour of the peripapillary nerve fiber layer from simultaneous stereoscopic videographic images. Parameters that describe this contour are defined and compared to standard optic nerve structural parameters (cup/disk ratio, disk rim area, cup volume) in three age-matched groups of patients: 52 normal controls, 79 glaucoma suspects, and 101 glaucoma patients. Greater discriminatory information was obtained from the measurements from the superior and inferior quadrants than from the measurements from the temporal and nasal quadrants. This approach helps identify new structural markers that may more closely reflect the number of ganglion cell axons in the optic nerve. Such measurements made longitudinally in living eyes will provide valuable information about the relative rates of ganglion cell death in aging and in glaucoma.

A subsidized perinatal care program in a rural Colorado county.

A large number of medically indigent women in rural areas currently receive little or no prenatal care, raising major concerns regarding perinatal health. In Colorado, subsidized prenatal and labor/delivery programs have been instituted to address this problem. This article describes the implementation of two programs in one rural county. In these rural programs, private physicians, health department personnel, and social work staff at the local hospital collaborate to provide financial assistance, comprehensive health education, and quality medical care for eligible pregnant women. The identified benefits and barriers unique to the provision of quality perinatal care in rural settings are discussed.

Adenylate cyclase stimulation and intraocular pressure reduction by forskolin analogs.

Forskolin and 18 chemical analogs of forskolin were assayed for stimulation of adenylate cyclase activity in vitro and for their effects on intraocular pressure (IOP) in vivo. Adenylate cyclase activity was determined with a preparation of corpora striata from male Wistar rats and test drug concentrations of 0.3 to 300 microM. IOP effect was monitored after a single topical ocular application of a 1% suspension of the test drug to male New Zealand albino rabbits. Significant reductions in IOP occurred with compounds which had potent cyclase stimulatory properties. Most compounds with little cyclase stimulatory effect produced little or no decrease in IOP. A 1-substituted morpholino-acetoxy derivative, which may be a prodrug metabolized to active form by corneal esterases, showed little cyclase stimulation in vitro but produced significant reductions in IOP.