Non-random mating in classical lekking grouse species: seasonal and diurnal trends.

This paper is the first to integrate both field and theoretical approaches to demonstrate that fertility benefits can be a direct benefit to females mating on the classical lek. Field data collected for male sharp-tailed grouse (Tympanuchus phasianellus), a classical lekking species, revealed potential fertility benefits for selective females. Adult males and individuals occupying centrally located territories on the lek were found to have significantly larger testes than juveniles and peripheral individuals. Further, using empirical data from previously published studies of classical lekking grouse species, time-series analysis was employed to illustrate that female mating patterns, seasonal and daily, were non-random. We are the first to show that these patterns coincide with times when male fertility is at its peak.

Cancer-associated human papillomavirus types are selectively increased in the cervix of women in the first trimester of pregnancy.

OBJECTIVE: Because of incomplete data in the current literature, we sought to determine whether pregnancy is an independent risk for the detection of human papillomavirus infection. STUDY DESIGN: Pregnant patients in their first trimester who are seen for routine care at an obstetrics clinic and nonpregnant patients receiving routine care at a sexually transmitted diseases clinic and a gynecology clinic were recruited. Cervical cells were collected by saline solution lavage, and deoxyribonucleic acid was extracted and tested for the presence of human papillomavirus deoxyribonucleic acid with the hybrid capture assay. This assay detects the deoxyribonucleic acid of five "low cancer risk" and nine "high cancer risk" human papillomavirus types with two separate pools of deoxyribonucleic acid probes. RESULTS: Results from 245 pregnant women, 248 patients from the sexually transmitted diseases clinics, and 246 gynecology clinic patients were analyzed. Human papillomavirus deoxyribonucleic acid was detected in samples from 31% of the pregnant patients compared with 17.7% and 18.6% of the sexually transmitted diseases clinic and gynecology clinic patients, respectively. There was no significant difference in positivity for the "low-risk" human papillomavirus types among the three groups (positivity rates from 8.9% to 12.7%), but the pregnant patients had a significantly higher positivity rate for the "high-risk" human papillomavirus types (24.9% compared with 13.3% and 11.4% for the sexually transmitted diseases and gynecology clinic patients, respectively; p < 0.001). A multiple logistic regression analysis showed that pregnancy was an independent predictor of a positive test result for a "high-risk" human papillomavirus type (odds ratio 1.79, 95% confidence interval 1.11 to 2.89) but not a positive test result for a "low-risk" type. CONCLUSIONS: Because sexual activity was not greater among the pregnant patients, we propose that the increased detection of "high-risk" human papillomavirus types among the pregnant patients represents a selective activation of these viruses by hormonal or immunologic factors associated with pregnancy.

Shoulder dystocia: an analysis of risks and obstetric maneuvers.

OBJECTIVE: The purpose of this study was to determine whether there is a risk profile for predicting or preventing shoulder dystocia and whether any of the obstetric maneuvers to disimpact a shoulder reduce the likelihood of permanent injury. STUDY DESIGN: A retrospective analysis of 14,297 parturients with 12,532 vaginal deliveries and 1765 cesarean sections (12.4%) from January 1986 through June 1990 was performed. A total of 204 maternal and infant charts, related to shoulder dystocia or neonatal injury, were reviewed in depth for age, parity, episiotomy, type of delivery, hemorrhage, maternal obesity, diabetes, weight gain, fetal weight, sex, and Apgar scores. In addition, the type of maneuver or combination thereof used to relieve the dystocia, type of injury to the infant, and follow-up of the injury were reviewed. RESULTS: The 185 coded episodes of shoulder dystocia represent 1.4% of all vaginal deliveries (12,532). There were 42 injuries recorded: 14 fractured clavicles and 28 brachial plexus injuries. An additional 19 patients, not coded for shoulder dystocia, sustained 14 fractured clavicles and five brachial plexus injuries. All but one of the brachial plexus injuries resolved by 6 months. The occurrence of shoulder dystocia increased in direct relationship to the birth weight and becomes significant in newborns over 4000 gm (p < 0.01). The occurrence of a previous large infant was also a significant risk factor (p < 0.01). Diabetes and midforceps delivery become significant factors only in the presence of a large fetus. Obesity, multiparity, postdate pregnancy, use of oxytocin, low forceps delivery, episiotomy, and type of anesthesia were unrelated to shoulder dystocia. No delivery method was without injury. CONCLUSIONS: This study clearly indicates that most of the traditional risk factors for shoulder dystocia have no predictive value, shoulder dystocia itself is an unpredictable event, and infants at risk for permanent injury are virtually impossible to predict. In addition, no delivery method in shoulder dystocia was superior to another with respect to injury. Thus no protocol should serve to substitute for clinical judgment.

Clinical characteristics and treatment of isolated inferior rectus paralysis.

Isolated inferior rectus paralysis without mechanical restriction of the globe has received only scant attention in the literature. The authors report on 21 patients treated during the past 16 years. The etiology was congenital, traumatic, myasthenic, and vascular. Anomalous head posture, diplopia, or a disfiguring hypertropia were presenting symptoms. Diagnosis was made on the basis of the prism and cover test in the diagnostic positions and on examination of ductions and versions. The direction of the head tilt, the Bielschowsky head tilt test, and tests for cyclotropia are only of secondary diagnostic value since they may give paradoxical results. Surgery consisted of resection of the paralyzed muscle, combined with or without recession of its antagonist and/or recession of the contralateral superior oblique. After a mean follow-up of 17 months, 14 patients were cured, 6 had improved, and 1 remained unchanged.

Pregnancy, abruptio placentae and cocaine.

Widespread cocaine use has caused concern about possible harmful effects during pregnancy. Several studies have suggested an increased incidence of abruptio placentae and stillbirths with cocaine use during pregnancy. This study examined what percentage of pregnant women in a lower socioeconomic population use cocaine, as well as positive urine cocaine screens in those with abruptio placentae and intrauterine fetal death (IUFD). Thirty patients were enrolled in the control group, eight in the abruptio placentae group and five in the IUFD group. One of 30 controls, one of eight in the abruptio placentae group and none of the IUFD group urines were positive for cocaine. A higher percentage of those in the abruptio placentae group had a history of abruptio placentae or fetal death, suggesting possible prior drug use. This group also had little, if any, prenatal care. Cocaine abusers may show signs of abuse in their obstetrical histories.

Vaginal birth after two or more cesarean sections: a five-year experience.

Allowing a trial of labor in patients who have had a single low transverse cesarean section has become increasingly accepted and widespread in the United States. Evidence with regard to the safety of this practice in patients with two or more prior cesarean births has, however, been sparse. We performed a retrospective review of the charts of 170 patients who had undergone two or more low transverse cesarean deliveries and subsequently delivered at Wishard Memorial Hospital between January 1, 1983, and December 31, 1987. Of 35 of these women who underwent a trial of labor, 27 (77%) had a successful vaginal delivery. No increase in maternal or fetal morbidity or mortality was associated with labor. The women who underwent trial of labor had fewer postpartum complications and shorter hospital stays. Although the number of patients in this study was small, growing evidence appears to support a trial of labor in patients with two or more prior cesarean sections as a safe and successful alternative to elective repeat cesarean section.

The management and treatment of an abnormal Pap smear.

Table 2 summarizes the management of the abnormal Pap smear. Management of dysplasia in this institution is aggressive--as destructive therapy of mild dysplasia is advised, opposed to watching the patient and treating only if the disease persists. The rationale for this is the 33% to 45% failure rate for follow-up appointments in the primarily inner-city population served. The key to follow-up is to repeat cervical cytology in all patients treated, even those treated with hysterectomy, every three months until two consecutive normal smears are obtained. At that time, surveillance and intervals may be modified, but screening should continue at least annually. The mortality rate of carcinoma of the cervix has dropped precipitously during the last 40 years, in part, from simple screening of the cervix with the Papanicolaou smear. The effort to treat premalignant changes has been rewarded. The use of the colposcope and destructive forms of therapy have allowed successful treatment of patients with less morbidity and mortality than the immediate reliance on cervical conization. Remember, conization is still indicated and prudent in selected patients. Following these guidelines may contribute to the downward trend.

Behavioral evolution and biocultural games: vertical cultural transmission.

We consider an evolutionary game model in which strategies are transmitted culturally from parents to offspring rather than inherited biologically. Our analysis yields two noteworthy results. First, biocultural games show a greater diversity of dynamical behaviors than their purely biological counterparts, including multiple fully polymorphic equilibria. Second, biocultural games on average exhibit greater equilibrium strategy diversity because of the countervailing influences of cultural transmission and natural selection. Therefore, knowledge of a strategy's influence on Darwinian fitness is not sufficient to infer the evolutionary consequences of biocultural games. Further, our results suggest that cultural transmission in the presence of natural selection may be an important mechanism maintaining behavioral diversity in natural populations.