Acute Effects of Enhanced Eccentric and Concentric Resistance Exercise on Metabolism and Inflammation.

This study compared the metabolic, cardiopulmonary and inflammatory responses of novel acute machine based concentrically-focused resistance exercise (CON RX) and eccentrically-focused resistance exercise (ECC RX). Twenty healthy adults (26.8 ± 5.9 yrs; 25.4 ± 4.0 kg/m2) performed two work-matched RX exercise sessions. Cardiopulmonary responses, rating of perceived exertion (RPE), soreness, oxygen consumption; (VO2) were collected during each session. Blood lactate and levels of inflammatory cytokines interleukin-1 alpha (IL1α), interleukin-6 (IL6) and tumor necrosis factor-alpha (TNFα) were analyzed pre, post ad 24 hours post-exercise. HR were higher (5-15bpm) during ECC RX (p<.05). Soreness ratings were consistently higher post-ECC RX compared to CON RX. VO2 area under the curve was higher during ECC than CON (31,905 ml/kg/min vs 25,864 ml/kg/min; p<.0001). Post-ECC RX, TNFα levels increased compared to CON RX 23.2 ± 23.9% versus 6.3 ± 16.2% ( p=.021). ECC RX induced greater metabolic, cardiopulmonary and soreness responses compared to matched CON RX. This may be due to recruitment of additional stabilizer muscles and metabolic stress during the ECC RX. These factors should be considered when designing ECC RX programs particularly for untrained persons, older adults or those with history of cardiovascular disease.

The clinical use of intrauterine pressure catheters.

We question the need for an intrauterine pressure catheter (IUPC) to monitor uterine contractions during the induction or augmentation of labor with oxytocin, or to verify adequate uterine contractions to support the diagnosis of arrest of labor. There are appropriately conducted clinical trials demonstrating that uterine contraction frequency in spontaneous, induced and augmented labors obtained with the use of external tocography is sufficient for the clinical management of labor. The value of an IUPC is further diluted by the inherent variability of pressure recordings with its use and the potential of the infrequent risks associated with insertion. Particularly pertinent is the fact that the use of an IUPC for this indication has never been proved to have a positive effect on maternal or neonatal outcome.

A blueprint for academic obstetrics and gynecology.

A consensus conference sponsored by the Council of University Chairs of Obstetrics and Gynecology in February 1997 formulated the organization's response to the many external issues affecting academic medicine and obstetrics and gynecology including 1) a new practice model based on "wellness," 2) reimbursement changes that have jeopardized traditional revenue sources, 3) an emphasis on quality assurance based on outcomes research and evidence-based medicine, 4) the concept of lifelong learning dictated by an expanding knowledge base and new technology, 5) insufficient resources for basic and clinical investigation in obstetrics and gynecology, 6) workforce statistics indicating stabilization in the number of subspecialists, 7) the increasing diversity of the United States population. Recommendations were developed that are intended to foster change and contribute to the design of academic programs. These include appropriate training for residents as providers of primary care, with an emphasis on continuity clinics, an interdisciplinary curriculum in women's health for medical students; promotion of gender, racial, and ethnic diversity at all levels of medical education and academic leadership; creation of clinical trials research units; and the development of expanded opportunities for research in obstetrics and gynecology supported by the National Institutes of Health.

Paralysis of the preterm rabbit fetus inhibits the pulmonary uptake of intraamniotic iron dextran.

OBJECTIVE: Whether fetal breathing movements or gasping result in the movement of amniotic fluid substances into the distal airways remains controversial. We evaluated the effect of paralysis of the preterm rabbit fetus on the pulmonary distribution of iron dextran. STUDY DESIGN: Laparotomy was performed on 10 New Zealand White rabbits of 25 days' gestation (term 31 days) under general anesthesia. Fetuses in one uterine horn were given an intramuscular injection of pancuronium (1.5 mg/kg) and fetuses in the other horn were given an equal volume of normal saline solution as controls. A 1 ml volume of iron dextran (100 mg/ml) was injected into the amniotic sac of all fetuses. The laparotomy was closed, and 20 to 24 hours later the fetuses were removed by hysterotomy and assessed for paralysis. Necropsy was performed. Lungs were stained with prussian blue and evaluated histologically for the presence of iron. RESULTS: A total of 92 pups were delivered (49 given pancuronium, 43 given normal saline solution), of which 64 were born alive. There were no differences between groups for live births (31 pancuronium, 33 normal saline solution), pup body weight, or lung weight. Pups given normal saline solution demonstrated more breathing motions, spontaneous movement, and brown (color of iron dextran) stomach contents than did the pups given pancuronium (p < 0.001). At necropsy a greater number of control pups (31/33) had brown lungs grossly compared with pups given pancuronium (2/31, p < 0.001). Lung histologic examination showed that more control pups (29/29) had iron in the trachea and main bronchi compared with pancuronium pups (0/27, p < 0.001), and more control pups (29/29) had iron in the distal lung airways compared with pancuronium pups (0/27, p < 0.001). With use of the Optimas Image Analysis System, iron in the lungs of control pups was found to be equally distributed between right versus left lungs, upper half versus lower half lungs, and anterior versus posterior lung sections. More iron was identified in the central airways than in the periphery (p < 0.001). CONCLUSION: We conclude that paralysis prevents the uptake of iron dextran into the main and distal airways of the rabbit fetus. Although lung fluid production results in a net efflux of fluid, we speculate that fetal breathing movements can result in the movement of fluid into distal airways and potentially provide fetal therapy.

Evaluation of postdoctoral physician-scientist training programs in obstetrics and gynecology.

Individuals previously awarded American Association of Obstetricians and Gynecologists Foundation/American Gynecological and Obstetrical Society or Reproductive Scientist Development Program postdoctoral physician-scientist training fellowship in Obstetrics and Gynecology were evaluated for their current status and research support. Forty-two (91%) of the first 44 fellows currently have medical school appointments, 15 at associate or full professor rank, and 75% have received extramural funding. These initial results are encouraging.

Hormonal regulatory adjustments during voluntary diving in Weddell seals.

Subadult male Weddell seals were instrumented with microcomputer-based backpacks and were then monitored during voluntary diving and recovery periods in McMurdo Sound, Antarctica. Depth and duration of diving, swim speed, and dive pattern were routinely monitored. An indwelling venous catheter was used to collect plasma samples at various time periods before and following diving episodes, so that changes in plasma concentrations of hormones and of metabolites could be measured. Adrenergic and nitroxidergic regulatory effects were assessed indirectly by measuring concentration changes in catecholamine and cyclic guanosine monophosphate (cGMP), respectively. The studies found that (i), except for dives of less than several minutes, epinephrine and norepinephrine both increased as a function of diving duration, then rapidly decreased during recovery (with a half time of about 10 min), (ii) that the changes in catecholamine concentrations correlated with splenic contraction and an increase in circulating red blood cell mass (hematocrit), (iii) that the changes in catecholamines, especially [epinephrine], were inversely related to insulin/glucagon ratios, which mediated a postdiving hyperglycemia, and (iv) that in long dives (but not short ones) the changes in catecholamines correlated with increasing reliance on anaerobic metabolism, indicated by increased plasma lactate concentrations. These diving-catecholamine relationships during voluntary diving at sea were similar to those observed during enforced submergence (simulated diving) under controlled laboratory conditions. At the end of diving, even while catecholamine concentrations were still high, many of the above effects were rapidly reversed and the reversal appeared to correlate with accelerated nitric oxide production, indirectly indicated by increased plasma cGMP concentrations. Taken together, the data led to the hypothesis of important adrenergic regulation of the diving response in seals, with rapid reversal at the end of diving and during recovery being regulated by nitroxidergic mechanisms.

Diurnal and gestational patterns of uterine activity in normal human pregnancy. The Uterine Activity in Pregnancy Working Group.

OBJECTIVES: To define the profile of 24-hour uterine activity in normal pregnancy and to correlate contraction frequency with physical activity and emotional stress diaries. METHODS: One hundred nine low-risk pregnant women who delivered at term recorded uterine contractions for 24 hours twice weekly from 20-40 weeks' gestation using an ambulatory monitor and kept a physical activity and emotional stress diary. Contractions per hour were calculated for each hour of the day and week of gestation, and related to physical activity and emotional stress. RESULTS: We analyzed 71,683 hours. No contractions were recorded in 73% of the hours, and fewer than four contractions per hour occurred in 96%. Significant inter-individual variability was noted. Contractions increased markedly with gestational age: The 95th percentile was 1.3 contractions per hour at 21-24 weeks, 2.9 at 28-32 weeks, and 4.9 at 38-40 weeks. A strong clustering of contractions occurred at night, which became pronounced after 24 weeks (night:day ratio 2:1 at 28-32 weeks). To adjust for the effects of gestational age and time of day, contractions per hour were converted to gestation- and hour-specific percentiles ("contraction percentiles"). Rest was associated with a fall in contraction percentile by 1.25, whereas coitus increased the contraction percentile by 5.52 (P < .05). No changes were noted with emotional stress. CONCLUSIONS: This study provides normative contraction data in uncomplicated pregnancy. A strong diurnal rhythm is present from 24 weeks onward, with 67% of contractions occurring at night. Contractions per hour increase with gestational age but rarely exceed three per hour before term. Rest and sexual activity have small but measurable effects on contraction frequency.

Preterm birth prevention: where are we?

OBJECTIVE: The purpose of this study was to review the current approaches to preventing preterm delivery. STUDY DESIGN: The problem of preterm birth was assessed by reviewing the different components that play a role in preterm birth prevention, excluding infection, antibiotic treatment, and tocolytic treatment. RESULTS: Prevention of preterm labor must initially discriminate those at risk. Positive predictive values of various approaches are currently not adequate enough to warrant intervention. Prevention modalities, in part because of poor prediction, are mostly unproved. Accurate diagnoses of preterm labor remains difficult and confuses analyses of tocolytic agents. Cervicovaginal fetal fibronectin, perhaps in combination with cervical evaluation, shows promise. Early detection programs remain controversial, but most reviews indicate that daily patient contact with high-risk patients gives cause for some optimism. Antenatal maternal glucocorticoid treatment at specific gestational ages improves neonatal outcome. CONCLUSION: The incidence of preterm birth is rising in the country. However, improved definition of the various components of the problem has provided an improved understanding of the problem. There is a new continuing effort and a search for new and innovative ways to address this vexing national problem.

A multicenter study of preterm birth weight and gestational age-specific neonatal mortality.

OBJECTIVE: This analysis was performed to present updated neonatal mortality data by age and birth weight for preterm newborns and to demonstrate the influence of plurality, ethnicity, and infant sex on mortality. STUDY DESIGN: Preterm birth weight and gestational age-specific mortality rates were compiled from the five centers that participated in the March of Dimes Multicenter Preterm Birth Prevention Project. In each center gestational age was assessed by standardized methods. A birth weight and gestational age-specific mortality chart for preterm births was created with live-birth data. RESULTS: In each birth weight group mortality decreased as the gestational age advanced; for each gestational age group heavier infants had less mortality. Female infants < 29 weeks survived better than male infants, and singletons < 29 weeks survived better than twins. Survival for black preterm newborns was better than that of whites but differences were not significant. Mortality for black term infants was significantly higher. The largest improvement in survival occurred between 25 and 26 weeks. At 30 weeks survival was > 90% and improved < 1% per week thereafter. CONCLUSIONS: When compared with rates in previous reports, mortality rates appear to have improved, especially at gestational ages < 29 weeks. These data may be useful in decision-making and in counseling patients at risk for preterm delivery.

Plasma thyroid hormones and prolactin in premature infants and their mothers after prenatal treatment with thyrotropin-releasing hormone.

We assayed TSH, triiodothyronine, free thyroxine, and prolactin (PRL) in plasma of women and infants participating in a trial of prenatal thyrotropin-releasing hormone (TRH) treatment for prevention of newborn lung disease. Women in labor at 26-34 wk of gestation received 400 micrograms of TRH i.v. every 8 h (one to four doses) plus 12 mg betamethasone (one or two doses); controls received saline plus betamethasone. Mean cord concentrations in control infants were TSH 9.7 mU/L, triiodothyronine 0.6 nmol/L (40.2 ng/dL), free thyroxine 14.4 pmol/L (1.13 ng/dL), and PRL 67.6 micrograms/L. TRH increased maternal plasma TSH by 100% at 2-4 h after treatment and decreased levels by 28-34% at 5-36 h. In cord blood of treated infants delivered at 2-6 h, TSH, triiodothyronine, and PRL were all increased about 2-fold versus control, and free thyroxine was increased 19%; the response was similar after one, two, three, or four doses of TRH. In treated infants delivered at 13-36 h, cord TSH and triiodothyronine levels were decreased 62 and 54%, respectively, and all thyroid hormones were lower after birth at 2 h of age versus control. We conclude that prenatal TRH administration increases thyroid hormones and PRL in preterm fetuses to levels similar to those normally occurring at term. Pituitary-thyroid function is transiently suppressed after treatment to a greater extent in fetus than mother, and infants born during the early phase of suppression do not have the normal postnatal surge in thyroid hormones.

Neonatal morbidity according to gestational age and birth weight from five tertiary care centers in the United States, 1983 through 1986.

OBJECTIVES: This study details the incidence, by gestational age and birth weight, of specific neonatal morbidities in singleton neonates without major congenital anomalies. STUDY DESIGN: Data were prospectively collected on all deliveries at five tertiary centers in the United States during the years 1983 through 1986. Pregnancies were meticulously dated and the gestational ages of the neonates at delivery were confirmed by Dubowitz score. RESULTS: The incidence of respiratory distress syndrome gradually decreases with increasing gestational age until 36 weeks. A marked decrease in the incidence of necrotizing enterocolitis, patent ductus arteriosus, intraventricular hemorrhage, and sepsis occurs after 32 completed weeks. The number of days of mechanical ventilation for respiratory distress syndrome and newborn stay in the tertiary care facility also were significantly reduced after 32 weeks. CONCLUSIONS: The incidence of both respiratory distress syndrome and patent ductus arteriosus is markedly decreased by both increasing gestational age and birth weight. The incidence of grade III and IV intraventricular hemorrhage, necrotizing enterocolitis, and sepsis virtually vanishes after 34 weeks. These data relating neonatal morbidities to gestational age are important to the obstetrician in the critical decision regarding the timing of delivery and to the parents, who can benefit from a realistic prediction of the neonatal course.

Respiratory disease in very-low-birthweight infants after prenatal thyrotropin-releasing hormone and glucocorticoid. TRH Study Group.

Although prenatal glucocorticoid treatment reduces neonatal respiratory morbidity, respiratory distress syndrome and chronic lung disease (CLD) develop in many very-low-birthweight infants despite therapy. To investigate the effect of additional prenatal treatment with thyrotropin-releasing hormone (TRH), we did a multicentre, blinded, randomised trial. 404 women with threatened preterm delivery at less than 32 weeks' gestation received betamethasone plus TRH (4 doses of 400 micrograms 8-hourly) or betamethasone plus placebo. 103 infants who were fully treated and of less than 1500 g birthweight were evaluated during the neonatal period. TRH treatment (55 infants) did not affect the total incidence of respiratory distress syndrome (47% vs 58% in controls) or of severe respiratory distress syndrome (13% vs 25% in controls, p = 0.11). CLD (defined as requirement for supplemental oxygen at 28 days after birth) developed in significantly fewer TRH-treated infants (18% vs 44% of controls, p less than 0.01). The unadjusted relative risk of CLD with TRH therapy was 0.40 (95% CI 0.26-0.80, p less than 0.05), and this was not materially changed after adjustment for potentially modifying variables. There were significantly fewer adverse outcomes, defined as death or continuing oxygen requirement, in the TRH group than in the steroid-alone group both at 28 days and when infants reached 36 weeks' postconceptional age. The incidence of other complications of prematurity was similar in the two groups. Prenatal TRH reduces the incidence of chronic lung disease among betamethasone-treated infants.

Evaluation of phenazopyridine hydrochloride as a tool in the diagnosis of premature rupture of the membranes.

This is a prospective study to determine whether a maternal orally administered azo dye, phenazopyridine hydrochloride, would cross into amniotic fluid, and thus be of potential aid in the diagnosis of rupture of the membranes. Based on anecdotal experience, we hypothesized that this compound would cross the placenta and be excreted in the fetal urine, causing discoloration of the amniotic fluid. Ten patients with uncomplicated pregnancies undergoing elective amniocentesis for obstetric indications received an oral dose of 400 mg of phenazopyridine hydrochloride 4 hours prior to the procedure. Amniotic fluid was also available from five control patients who did not receive phenazopyridine hydrochloride. The typical orange-to-red discoloration of the urine was seen in all study patients, indicating ingestion of the dye. None of the ten patients had evidence of the azo dye in their amniotic fluid by visual inspection or by spectrophotometric absorbance. After the amniotic fluid samples were acidified, the presence of the azo dye was visually demonstrable, and spectrophotometry confirmed measurable concentrations (mean +/- SE: 13.08 +/- 0.72 micrograms/ml). We conclude that although phenazopyridine hydrochloride does cross the placenta into the fetal compartment, its presence causes a visual and spectrophotometric change in the color of amniotic fluid only when the normal basic pH of amniotic fluid is acidified.

Lifestyle influences on prematurity.

It is apparent from this review that the lifestyle of an individual gravida can potentially lead to a premature delivery. Some of these adverse behavioral characteristics may be dealt with by education and motivation, and some with actual medical treatment. However, there also appears to be significant need for public policy reorientation if we are to make a significant impact on the problem of preterm delivery.

Prevention of preterm birth: clinical opinion.

Spontaneous preterm delivery continues to be the most significant problem facing clinicians as we enter the 1990s. Prevention of preterm labor still awaits needed improvements in prediction. At present, most preterm birth prevention programs are based upon the early recognition of preterm labor followed by prompt tocolysis. Programs based upon patient education and support, daily contact by trained nurses, intermittent cervical assessment, and daily sampling of uterine activity have been associated with a decrease in preterm birth. The exact contribution of each component to reduce preterm birth remains to be defined and, at present, a combination of the components is still suggested.

Early signs and symptoms of preterm labor.

Patient and staff education concerning the subtle signs and symptoms that precede a clinical diagnosis of preterm labor have not been well established. Therefore we interviewed 100 patients for the presence or absence of various symptoms and signs during the 7 days preceding diagnosis of preterm labor. An additional 100 patients without preterm labor matched for gestation were chosen at random as control subjects. A history of increased uterine contractions, menstrual cramps, constant backache, constant pelvic pressure, increased amount and consistency and color change of vaginal discharge, and increased frequency of urination were present with a statistically significant higher frequency in patients with preterm labor compared with controls. Twenty-nine percent of patients did not report any uterine contractions and only half described them as painful. Fewer than 50% of the women reported contractions as frequently as every 10 minutes or more.