THE NATIONAL BIRTH CENTER STUDY Part II—Intrapartum and Immediate Postpartum and Neonatal Care

Part II of a three-part report of the National Birth Center Study describes care provided to 11,814 women and their newborns during and after labor and delivery until they were transferred or discharged from the birth centers. There were few low birth weight or preterm or postterm births, but more macrosomic babies than among all U.S. births during the same time period. Certified nurse-midwives provided most of the intrapartum care, which is described in the context of medically recommended standards and data that describe care provided to low-risk women giving birth in U.S. hospitals. Birth center care deviated from typical hospital care in several ways. Birth center clients were much less likely to receive central nervous system depressants, anesthesia, continuous electronic fetal monitoring, induction and/or augmentation of labor, intravenous infusions, amniotomies, or episiotomies, and they had relatively few vaginal examinations. They were more likely to eat solid food during labor and to take showers and/or baths Nulliparity was strongly associated with longer first stage labors and longer labor was associated with more frequent use of many kinds of interventions. Infant birth weight, mother's position during delivery, and forceps- or vacuum-assisted deliveries are examined in relation to episiotomies and lacerations and tears.     

Chronic health conditions and school performance among children and youth

PurposeChronic health conditions are common and increasing among U.S. children and youth. We examined whether chronic health conditions are associated with low school performance.MethodsThis retrospective cohort study of 22,730 children and youth (grades 2–11) in San Jose, California, was conducted from 2007 through 2010. Health conditions were defined as chronic if reported in each of the first 2 years, and school performance was measured using standardized English language arts (ELA) and math assessments.ResultsChronic health conditions were independently associated with low ELA and math performance, irrespective of ethnicity, socioeconomic status, or grade level. Adjusted odds ratios for the association between any chronic health condition and low (“basic or below”) performance were 1.25 (95% confidence interval [CI], 1.16–1.36; P < .001) for ELA and 1.28 (95% CI, 1.18–1.38; P < .001) for math, relative to students without reported health conditions. Further adjustment for absenteeism had little effect on these results. The strongest associations were found for ADHD, autism, and seizure disorders, whereas a weak association was found for asthma before but not after adjusting for absenteeism, and no associations were found for cardiovascular disorders or diabetes.ConclusionsChronic neurodevelopmental and seizure disorders, but not cardiovascular disorders or diabetes, were independently associated with low school performance among children and youth.     

Immunolocalization of the Ca2+-activated K+ channel Slo1 in axons and nerve terminals of mammalian brain and cultured neurons

Ca(2+)-activated voltage-dependent K(+) channels (Slo1, KCa1.1, Maxi-K, or BK channel) play a crucial role in controlling neuronal signaling by coupling channel activity to both membrane depolarization and intracellular Ca(2+) signaling. In mammalian brain, immunolabeling experiments have shown staining for Slo1 channels predominantly localized to axons and presynaptic terminals of neurons. We have developed anti-Slo1 mouse monoclonal antibodies that have been extensively characterized for specificity of staining against recombinant Slo1 in heterologous cells, and native Slo1 in mammalian brain, and definitively by the lack of detectable immunoreactivity against brain samples from Slo1 knockout mice. Here we provide precise immunolocalization of Slo1 in rat brain with one of these monoclonal antibodies and show that Slo1 is accumulated in axons and synaptic terminal zones associated with glutamatergic synapses in hippocampus and GABAergic synapses in cerebellum. By using cultured hippocampal pyramidal neurons as a model system, we show that heterologously expressed Slo1 is initially targeted to the axonal surface membrane, and with further development in culture, become localized in presynaptic terminals. These studies provide new insights into the polarized localization of Slo1 channels in mammalian central neurons and provide further evidence for a key role in regulating neurotransmitter release in glutamatergic and GABAergic terminals.     

Free vascularized fibular grafting following failed core decompression for femoral head osteonecrosis

The results of treatment of femoral head osteonecrosis with free vascularized fibular grafting (FVFG) following failed core decompression (core decompression-FVFG [CD-FVFG] group: 32 hips) were reviewed and compared with those of a control group that underwent FVFG only (54 hips). Outcome was considered unsuccessful if total hip arthroplasty was subsequently performed. Total hip arthroplasty was performed in 15 and 20 hips of the CD-FVFG and control groups, respectively. When considering age, sex, and presence of bilateral disease, patients with previous core decompression did not have a significantly different failure rate from patients with FVFG only. However, patients with preoperative stage V osteonecrosis or corticosteroid use had worse outcomes after vascularized fibular grafting if they had a previous core decompression of the femoral head.     

Free vascularized fibular bone grafting in the management of femoral neck nonunion in patients younger than fifty years

PURPOSE: The incidence of nonunion and osteonecrosis after femoral neck fracture has been well documented. In older patients implant arthroplasty is well established as an acceptable treatment of these problems. However, in the younger population alternatives to implant arthroplasty are favored to preserve the femoral head. Surgical treatments for nonunion of the femoral neck include osteotomy, nonvascularized bone grafting, muscle-pedicle bone grafting, and vascularized bone grafting. The purpose of this study is to examine the results of free vascularized fibular grafting as a treatment of nonunion of the femoral neck in patients younger than fifty years. MATERIALS AND METHODS: Twenty-two consecutive patients underwent vascularized bone grafting for nonunion of the femoral neck after failed internal fixation between 1984 and 1998. The mean age of the patients was 28.7 years. There were thirteen male and nine female patients. The mean interval between internal fixation and free vascularized fibular grafting was 18.3 months. The average follow-up to date is 84.7 months (range 29 to 195 months). RESULTS: Twenty of twenty-two nonunions healed. Two patients required an additional procedure to facilitate union; one patient had iliac crest bone grafting at four months postoperatively and another underwent muscle-pedicle grafting at six months postoperatively. The average time to union for all patients was 9.9 months (range 3 to 23 months). Progression of osteonecrosis of the femoral head occurred in thirteen patients. However, successful long-term salvage of the femoral head was achieved in twenty of twenty-two patients, with an average Harris hip score of 78.9. Four patients required hardware removal or exchange for intraarticular migration with no long-term clinical sequelae. DISCUSSION: Rates of complications, such as nonunion and osteonecrosis, after femoral neck fractures in young patients have been reported to be as high as 86 percent. Treatments such as osteotomy, muscle-pedicle bone grafting, nonvascularized bone grafting, and vascularized bone grafting have reported variable results. Based on the results reported in this study, vascularized fibular bone grafting compares favorably with a high union rate (91 percent initially, 100 percent after secondary procedures) and successful long-term salvage of the femoral head in 91 percent of the patients. Free vascularized fibular bone grafting represents a promising solution for this difficult problem.     

Effects of tezosentan, a dual endothelin receptor antagonist, on the cardiovascular and renal systems of neonatal piglets during endotoxic shock

Background/Purpose: Endothelin is a potent mediator of the cardiovascular and renal systems. Studies have found that endothelin has an important role in regulating cardiac function and renal perfusion in neonates who are suffering from endotoxic shock. The authors believe that blockade of the endothelin response during endotoxemia will have a beneficial effect on neonatal cardiac and renal functions. In this study the authors have examined the effects of tezosentan, a dual endothelin-receptor antagonist, on the cardiovascular and renal systems of neonatal piglets during endotoxemia. Methods: Thirteen piglets were subjected to endotoxic shock and divided into a fluid-therapy group that received 0.9% normal saline and a group that received tezosentan (1 mg/kg/h). Mean arterial pressure (MAP), heart rate (HR), and glomerular filtration rate (GFR) were plotted at baseline, 1, 2, and 3 hours. Cardiac index (CI), renal blood flow (RBF), systemic vascular resistance (SVR), and renal vascular resistance (RVR) were obtained at baseline, 1, and 3 hours after baseline. Results: (P [lt ] .05 for 3 hours versus baseline and tezosentan versus fluid). Although fluid therapy in endotoxemia had no significant effect on MAP and RVR, it significantly increased HR (139 [plusmn] 17 to 246 [plusmn] 17 beats/min) and SVR (0.08 [plusmn] 0.05 to 0.33 [plusmn] 0.09 mm Hg/mL/min) and decreased CI (407 [plusmn] 208 to 98 [plusmn] 13 mL/min/kg), RBF (1.84 [plusmn] 0.38 to 0.97 [plusmn] 0.34 mL/min/kg kidney), and GFR (0.20 [plusmn] 0.05 to 0.11 [plusmn] 0.04 mL/min/kg) at 3 hours. The use of tezosentan also significantly increased HR (130 [plusmn] 14 to 220 [plusmn] 31 beats/min), but unlike in the fluid therapy group, there was a significant fall in MAP (77 [plusmn] 10 to 54 [plusmn] 9 mm Hg) and RVR (1.92 [plusmn] 0.44 to 1.77 [plusmn] 0.64 mm Hg/mL/min) and a less severe decrease in CI (482 [plusmn] 188 to 176 [plusmn] 67 mL/min/kg) at 3 hours. SVR, RBF, and GFR were maintained. Conclusions: Endotoxic shock affected cardiac and renal functions in both treatment groups. Fluid therapy alone could not prevent a statistically significant fall in CI, RBF, and GFR or prevent the increase in HR and SVR. Endothelin antagonism with tezosentan resulted in a statistically significant fall in MAP and RVR from baseline, not seen in the fluid-therapy group. CI and RBF were significantly higher, and MAP, SVR, and RVR were significantly lower when compared with the fluid-therapy group at 3 hours. GFR also was maintained at baseline with tezosentan. During endotoxemia, endothelin antagonism maintained renal and cardiac functions better than with fluid therapy alone.     

Muscle maintenance by volitional contraction against applied electrical stimulation

Muscle training exercises are needed for muscular endurance during spaceflight. This study was designed to investigate effects of volitional contraction against applied electrical stimulation on the muscular endurance of the proximal upper extremity. Thirteen healthy sedentary men were allocated into two groups. One group participated in a hybrid (HYB) exercise regimen in which the biceps brachii was stimulated as he volitionally extended his elbow, and the triceps brachii was stimulated as the volitionally flexed his elbow. The second group underwent a similar regimen in which the electrical stimulation (ELS) was alternatively delivered to the biceps brachii and then to the triceps brachii with the limb fixed. Forty-second surface electromyography (EMG) recordings at 50% maximum voluntary contraction (MVC) were made as baseline data at just before starting the training regimen, and again conclusion. The median frequency (MF) and mean power frequency (MPF) slopes with time were determined using power spectrum analysis. There were statistical significance only for the triceps in which the MF and MPF slopes in the HYB Group became less negative over the period of study (from -45.7+/-14.7 and -47.0+/-8.6%/min at baseline to -36.9+/-10.7 and -36.8+/-7.0%/min at the end of training, respectively). The corresponding values for these slopes in the ELS Group showed opposite tends with less marked changes of borderline significance for MF and of statistical significance for MPF. These results suggested that the HYB exercise regimen was capable of producing an improvement in triceps but not biceps brachii.     

Seasonal variation of Lutzomyia longipalpis (Lutz & Neiva, 1912) (Diptera: Psychodidae: Phlebotominae) in endemic area of visceral leishmaniasis, Campo Grande, state of Mato Grosso do Sul, Brazil

The seasonal distribution of Lutzomyia longipalpis was studied in two forested and five domiciliary areas of the urban area of Campo Grande; MS, from December 2003 to November 2005. Weekly captures were carried out with CDC light traps positioned on ground and in the canopy inside a residual forest and on the edge (ground) of a woodland and in at least one of the following ecotopes in peridomiciles-a cultivated area, a chicken coop, a pigsty, a kennel, a goat and sheep shelter and an intradomicile. A total of 9519 sand flies were collected, 2666 during the first year and 6853 during the second. L. longipalpis was found throughout the 2-year period, presenting smaller peaks at intervals of 2-3 months and two greater peaks, the first in February and the second in April 2005, soon after periods of heavy rain. Only In one of the woodlands was a significant negative correlation (p<0.05) between the number of insects and temperature during the first year and the climatic factors (temperature, RHA and rain) was observed. In the domiciliary areas in four domiciles some positive correlations (p< or =0.05) occurred in relation to one or more climatic factors; however, the species shows a clear tendency to greater frequency (72%) in the rainy season than in the dry (28%). Thus, we recommend an intensification of the VL control measures applied in Campo Grande, MS, during the rainy season with a view to reducing the risk of the transmission of the disease.