Nitrous oxide, methane and carbon dioxide patterns and dynamics from an experimental pig mass grave.

The objective of the three-year study was to examine spatial and temporal patterns of fluxes and soil pore air concentrations of methane (CH4), carbon dioxide (CO2) and nitrous oxide (N2O) from an experimental mass grave located in a temperate environment. The mass grave (5×10m) contained twenty pig carcasses at a depth of approximately 1m was compared to a plot of the same dimensions containing only disturbed soil, as well as an undisturbed plot. Soil pore air CH4 concentrations were sub-ambient (<1.8ppm) except at 75 and 100cm depths at the mass grave in years 1 and 2 but decreased in year 3. The consumption of CH4 within the aerobic soil resulted in small negative fluxes at the soil surface. Soil pore air CO2 concentration showed an increase with depth in all three plots, with the largest increase (>100,000ppm at 1m) in the mass grave, though there was a marked decrease from years 1 to 3. Surface fluxes of CO2 showed strong seasonal variations, peaking in summer. Soil pore air N2O concentration showed major increases in the mass grave, compared to the other two plots with the pattern maintained over the three years, resulting in larger surface fluxes of N2O. To establish the role of the carcasses in N2O dynamics, we incubated a soil sample containing carcass material which resulted in fast rates of N2O production and consumption. The maintenance of elevated pore air concentration and surface flux of N2O throughout the 3 years suggests that this is a long-term pattern and likely the best of the three gases to use to detect graves. Thus, we suggest that measurement of soil pore air concentrations, especially of N2O, could be a simple and effective approach to help determine the location of clandestine graves.

Nitrous oxide, methane and carbon dioxide dynamics from experimental pig graves.

Twelve pig carcasses were buried in single, shallow and deep (30 and 90 cm, respectively) graves at an experimental site near Ottawa, Ontario, Canada, with three shallow and three deep wrapped in black plastic garbage bags. An additional six carcasses were left at the surface to decompose, three of which were bagged. Six reference pits without remains were also dug. The objective of this three-year study was to examine the biogeochemistry and utility of nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2) in grave detection and whether grave depth or cadaver condition (bagged versus bare) affected soil pore air concentrations and emission of the three gases. Graves showed significantly higher (α=0.05) concentrations and surface fluxes of N2O and CO2 than reference pits, but there was no difference in CH4 between graves and reference pits. While CH4 decreased with depth in the soil profiles, N2O and CO2 showed a large increase compared to reference pits. Shallow graves showed significantly higher emissions and pore air concentrations of N2O and CO2 than deep graves, as did bare versus bagged carcasses.

The association of inadequate mid-pregnancy weight gain and preterm birth in twin pregnancies.

OBJECTIVE: To determine whether inadequate gestational weight gain in the second trimester in twin pregnancies is associated with an increased risk of preterm birth (PTB) at <32 weeks. STUDY DESIGN: Retrospective cohort study including 489 twin pregnancies delivered between 2001 and 2013. Rates of weight gain at different gestational ages were compared with Institute of Medicine guidelines. RESULT: An inadequate rate of weight gain at <20 weeks was not associated with PTB. Patients with inadequate rates of weight gain at 20 to 28 weeks had a higher risk of PTB at <32 weeks (37.6%) compared to those with adequate weight gain (15.2%) (P<0.001). In multivariate analysis, women with inadequate weight gain at 20 to 28 weeks were 2.8 times more likely to deliver at <32 weeks (95% confidence interval 1.65 to 4.81). CONCLUSION: Inadequate gestational weight gain at 20 to 28 weeks in twin pregnancies was the strongest predictor of PTB at <32 weeks. This represents an optimal time for interventions to improve weight gain and potentially decrease rates of PTB.

Comparison of irrigation and intravenous antibiotic prophylaxis at cesarean section.

Despite recent enthusiasm for antibiotic prophylaxis by uterine irrigation at the time of cesarean section, no data exists comparing the efficacy of this technique with standard intravenous antibiotic administration. Therefore, 124 patients about to undergo cesarean section were entered into a prospective, randomized, double-blind evaluation of uterine irrigation versus intravenous administration of either normal saline or cefoxitin. All women were considered to be at increased risk for postoperative infection because of the presence of labor or ruptured membranes. The incidence of endometritis and the fever index in patients receiving intravenous cefoxitin (3.2%, 4.6 degree hours) was significantly less than in patients receiving intravenous normal saline (21.2%, 22.3 degree hours). There was no significant difference between the use of intravenous normal saline and uterine irrigation with either cefoxitin (18.9%, 16.6 degree hours) or normal saline (17.4%, 24.6 degree hours). These results suggest that intravenous infusion is the most effective means of administering cefoxitin as a prophylactic antibiotic.

Staphylococcal septicemia and adult respiratory distress syndrome in pregnancy treated with extracorporeal carbon dioxide removal.

BACKGROUND: Septicemia in pregnancy may take an especially fulminant course. Adult respiratory distress syndrome (RDS) and disseminated intravascular coagulation (DIC) are associated life-threatening complications. Treatment consists of appropriate antibiotic coverage and supportive measures. CASE: A previously healthy 21-year-old woman presented at 26 weeks' gestation with staphylococcal sepsis of undetermined origin. Her course was complicated by the rapid onset of adult RDS, DIC, and multi-organ-system failure, resulting in preterm delivery. Despite maximal ventilatory support, her pulmonary status continued to deteriorate. She was treated ultimately with extracorporeal carbon dioxide removal and survived without serious sequelae. CONCLUSION: Extracorporeal carbon dioxide removal may improve survival in gravidas with adult RDS by decreasing the required airway pressures for ventilation, thus permitting pulmonary recovery.

Gestational diabetes mellitus: antenatal variables as predictors of postpartum glucose intolerance.

OBJECTIVE: To determine whether antepartum variables can predict postpartum glucose intolerance. METHODS: Glucose tolerance was assessed 6 weeks postpartum in 94 of 238 women with gestational diabetes using a 2-hour, 75-g oral glucose tolerance test (GTT). Selected antepartum variables were analyzed for predictive ability for postpartum glucose intolerance. RESULTS: Of 238 patients, 94 (39%) returned for a GTT. Those returning and those not returning were similar in all variables. Postpartum glucose intolerance occurred in 34%: impaired glucose tolerance in 18%, overt diabetes in 16%. No single maternal, intrapartum, or neonatal variable was predictive of postpartum glucose intolerance in all cases. Predictive variables included: requirement for insulin (insulin versus diet: 25 versus 3% impaired glucose tolerance, 26 versus 0% diabetes; P = .001), poor glycemic control (any 2-hour postprandial blood sugar level of 150 mg/dL or higher: 34 versus 5% diabetes; P = .005), and the 50-g GTT value (200 mg/dL or higher: 32 versus 6% diabetes; P = .01). For insulin requirement, the relative risk (RR) was 17.28 (95% confidence interval [CI] 2.46-121.45), and for the above three variables combined, the RR was 19.68 (95% CI 2.88-134.2). When the insulin dose was at least 100 U/day, all patients had abnormal glucose tolerance postpartum (RR = 34.00, 95% CI 4.93-234.39). CONCLUSIONS: Postpartum glucose screening is not warranted for women at low risk who do not require insulin during pregnancy. The incidence of postpartum glucose intolerance in this group is very low. Women with risk factors should receive postpartum screening. Patients receiving at least 100 U/day of insulin have a 100% incidence of postpartum glucose intolerance.

Continuous subcutaneous insulin infusion in an obese insulin-resistant pregnant woman with type II diabetes: accelerated fetal growth and neonatal complications.

This is the first report to describe prolonged continuous subcutaneous insulin infusion in a massively obese insulin-resistant pregnant woman with type II diabetes. Maternal 24-hour plasma glucose levels became normal by 48 hours, and normoglycemia was maintained with high daily doses of insulin (530 U-333 U/24 hours) from 29 weeks' gestation until delivery at 38.5 weeks. Excellent diabetic control was associated with euglycemia, normal glycosylated hemoglobin concentration, and a significant decrease in mean 24-hour plasma C-peptide (P less than .004) and glucagon (P less than .003) levels. Unexpectedly, fetal growth accelerated during constant insulin infusion despite normal maternal plasma glucose levels. The newborn infant was large (4530 g), with a striking truncal accumulation of fat, hypoglycemia (30-minute plasma glucose 11 mg/dL), and polycythemia (central venous hematocrit 71%). Normalization of maternal plasma glucose levels failed to ameliorate established macrosomia, and did not prevent the neonatal complications that are common in infants of diabetic mothers.

The prognostic value of hemoglobin A1c in predicting fetal heart disease in diabetic pregnancies.

OBJECTIVE: To evaluate detailed fetal echocardiography for predicting congenital heart disease in overt diabetic pregnancies. METHODS: Overt diabetic gravidas with initial hemoglobin A1c (HbA1c) at or above 8.5%, a family history of congenital heart disease, or fetal cardiac anomaly suspected on screening sonography were referred to a pediatric cardiologist for detailed fetal echocardiography. After 7 years, the results of the protocol were reviewed retrospectively. The sensitivity and specificity of the initial HbA1c in predicting congenital heart disease were assessed. RESULTS: During the study period, 193 patients received care in the diabetes and pregnancy service. Sixty-four received fetal echocardiography, 47 because of initial HbA1c levels at or above 8.5% and 17 for other indications. Twenty fetuses had major anomalies, eight of which were cardiac (40%). Six of the cardiac anomalies had been studied by fetal echocardiography, and four were diagnosed correctly. The initial HbA1c was not different among pregnancies with major anomalies, cardiac anomalies, or no anomalies. No malformations were noted in patients with normal initial HbA1c values. The overall sensitivity of the protocol for identifying congenital heart disease was 50% (four of eight) and specificity was 54% (90 of 167). Detailed fetal echocardiography had a sensitivity of 66% (four of six) and a specificity of 100% (58 of 58) for correctly identifying fetal congenital heart disease. CONCLUSIONS: No cases of congenital heart disease were observed in patients with a normal initial HbA1c value. Among patients with abnormal HbA1c values, no critical level of glycohemoglobin was identified that provided optimal predictive power for congenital heart disease screening. We recommend detailed fetal echocardiographic imaging in all patients with initial HbA1c levels above the upper limit of normal of 6.1%.

The reliability and predictive value of an amniotic fluid scoring system in severe second-trimester oligohydramnios.

Sixty-two cases of oligohydramnios diagnosed by ultrasound between 13-28 weeks' gestation were reviewed. Three experienced ultrasonographers used a subjective scale to rate the oligohydramnios as mild, moderate, severe, or anhydramniotic. Interobserver reliability was excellent (intraclass correlation coefficient 0.81). The overall perinatal mortality rate was 43%, and the incidence of pulmonary hypoplasia was 33%. One-third had lethal congenital anomalies. The frequency of adverse outcome correlated strongly with the most severe degrees of oligohydramnios; 88% of the fetuses with severe oligohydramnios or anhydramnios had lethal outcomes, compared with 11% in the mild/moderate group. The presence of an anuric urinary tract anomaly was associated with the most severe grades of oligohydramnios and was uniformly fatal. Pulmonary hypoplasia was diagnosed in 60% of the severe group versus 6% in the moderate group. We conclude that subjective grading of oligohydramnios by experienced observers is both reliable and predictive of outcome. The finding of severe oligohydramnios in the second trimester is highly predictive of poor fetal outcome and should stimulate a thorough search for etiology and consideration of intervention. Moderate grades of reduced amniotic fluid may be managed with relative optimism.

Fetal weight prediction by thigh volume measurement with three-dimensional ultrasonography.

OBJECTIVE: To evaluate the usefulness and accuracy of a simple method of predicting fetal weight by measuring fetal thigh volume with three-dimensional ultrasonography. METHODS: In 84 pregnant women, fetuses without structural or chromosomal anomalies were studied prospectively and cross-sectionally. Biparietal diameter (BPD), abdominal circumference (AC), and femur length (FL) were measured by two-dimensional ultrasound. Fetal thigh volume was measured by three-dimensional ultrasound, using three cross-sectional images of femur, from proximal, middle, and distal parts of femur diaphysis. Infants were delivered within 48 hours after ultrasound examinations. RESULTS: Modified thigh volume measurements using three cross-sectional images of femur by three-dimensional ultrasound were correlated strongly with birth weight (R(2) = 0.921, P <.001). Using linear and polynomial regression, we calculated a new best-fit formula: Birth weight (g) = 165.32 + 28.78 x modified thigh volume (mL). The mean and standard deviation of the residual were 121.8 and 110.4, respectively, in three-dimensional formulas, which were significantly smaller than those of two-dimensional formulas. CONCLUSION: Thigh volume measurement using three cross-sectional images of femur by three-dimensional ultrasound was simple, and there was better accuracy with this method than with two-dimensional ultrasound methods for predicting fetal weight during the third trimester of pregnancy.

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.

Fetal electrolyte and acid-base responses to amnioinfusion: lactated Ringer's versus normal saline in the ovine fetus.

OBJECTIVE: We hypothesized that amnioinfusion with normal saline would increase fetal plasma sodium and chloride concentrations, resulting in a hyperchloremic acidosis, and that these alterations would not occur after amnioinfusion with lactated Ringer's solution. METHODS: Chronically catheterized fetal sheep (137 +/- 1 days' gestation; mean +/- SE) were divided into three groups: control (n = 8), infused with normal saline (n = 10), and infused with lactated Ringer's solution (n = 10). The protocol consisted of a 30-minute pre-infusion period, a 1-hour amnioinfusion, and a 1-hour recovery period. During amnioinfusion, warmed solution was infused at a rate of 100 mL/minute for 1 hour. Fetal plasma and amniotic fluid electrolyte concentrations and osmolalities were measured every 20 minutes. Statistical analysis was by analysis of variance and linear regression. RESULTS: Amniotic fluid electrolyte concentrations changed significantly (P < .001) in both amnioinfusion groups, resulting in amniotic fluid compositions that were essentially the same as the infused fluid 20 minutes after starting the amnioinfusion. Significant increases in fetal plasma Na+ and CI- concentrations (2-3 mEq/L) occurred in the normal-saline infusion group relative to both the control and lactated Ringer's groups (P < .001). The lactated Ringer's group demonstrated only a modest increase in plasma Na+ (P = .04) and no change in plasma Cl- concentration. Fetal arterial pH decreased (-0.015 U) in the normal-saline group, and the change in fetal pH was linearly related to the change in plasma Cl- concentration (r = -0.532, P = .004). CONCLUSIONS: Normal-saline amnioinfusion can significantly alter fetal plasma electrolyte concentrations and blood pH, whereas amnioinfusion with lactated Ringer's solution results in minimal changes in fetal electrolytes and acid-base balance. The fetal plasma changes that occur during saline infusion are in the physiologic but not the pathologic range.

Environmental controls on the photosynthesis and respiration of a boreal lichen woodland: a growing season of whole-ecosystem exchange measurements by eddy correlation.

Measurements of net ecosystem CO2 exchange by eddy correlation, incident photosynthetically active photon flux density (PPFD), soil temperature, air temperature, and air humidity were made in a black spruce (Picea mariana) boreal woodland near Schefferville, Quebec, Canada, from June through August 1990. Nighttime respiration was between 0.5 and 1.5 kg C ha-1 h-1, increasing with temperature. Net uptake of carbon during the day peaked at 3 kg C ha-1 h-1, and the daily net uptake over the experiment was 12 kg C ha-1 day-1. Photosynthesis dropped substantially at leaf-to-air vapor pressure deficit (VPD) greater than 7 mb, presumably as a result of stomatal closure. The response of ecosystem photosynthesis to incident PPFD was markedly non-linear, with an abrupt saturation at 600 µmol m-2 s-1. This sharp saturation reflected the geometry of the spruce canopy (isolated conical crowns), the frequently overcast conditions, and an increase in VPD coincident with high radiation. The ecosystem light-use efficiency increased markedly during overcast periods as a result of a more even distribution of light across the forest surface. A mechanistic model of forest photosynthesis, parameterized with observations of leaf density and nitrogen content from a nearby stand, provided accurate predictions of forest photosynthesis. The observations and model results indicated that ecosystem carbon balance at the site is highly sensitive to temperature, and relatively insensitive to cloudiness.

Cervical ripening and labor outcome with preinduction intracervical prostaglandin E2 (Prepidil) gel.

Delivery with an unfavorable cervix using oxytocin is frequently unsuccessful. Used widely in Europe and increasingly in this country, locally applied prostaglandin E2 appears to improve labor induction. The present study prospectively evaluated the efficacy and safety of a prostaglandin gel (0.5 mg) placed intracervically. The use of the gel, when compared to a control group who received no pretreatment prior to labor induction, resulted in improved Bishop scores (7.5 +/- 1.0 vs. 1.8 +/- 0.3, P less than 0.0001), reduced induction to delivery intervals (10.1 +/- 2.1 vs. 20.6 +/- 2.0 hours), reduced oxytocin infusion duration (10.0 +/- 2.1 vs. 20.0 +/- 2.3 hours. P less than 0.0001) resulting in a lower cesarean delivery rate, 26 vs. 47 per cent (P greater than 0.05). Thirty-two per cent of patients receiving the prostaglandin gel labored and delivered within 12 hours and required no oxytocin. In addition, the use of prostaglandin E2 gel appeared safe in that no patient experienced an untoward reaction. Two cases of uterine hyperstimulation occurred that required uterine tocolysis but were not associated with fetal distress. The use of prostaglandin gel appears to be a safe and effective method to improve cervical inducibility in patients undergoing induction for a variety of maternal and fetal indications.

Gaseous carbon dioxide and methane, as well as dissolved organic carbon losses from a small temperate wetland under a changing climate.

Temperate forests can contain large numbers of wetlands located in areas of low relief and poor drainage. These wetlands can make a large contribution to the dissolved organic carbon (DOC) load of streams and rivers draining the forests, as well as the exchange of methane (CH4) and carbon dioxide (CO2) with the atmosphere. We studied the carbon budget of a small wetland, located in Kejimkujik National Park, Nova Scotia, Canada. The study wetland was the Pine Marten Brook site, a poor fen draining a mixed hardwood-softwood forest. We studied the loss of DOC from the wetland via the outlet stream from 1990 to 1999 and related this to climatic and hydrologic variables. We added the DOC export information to information from a previously published model describing CH4 and CO2 fluxes from the wetland as a function of precipitation and temperature, and generated a new synthesis of the major C losses from the wetland. We show that current annual C losses from this wetland amount to 0.6% of its total C mass. We then predicted that under climate changes caused by a doubling of atmospheric CO2 expected between 2040 and 2050, total C loss from the wetland will almost double to 1.1% of total biomass. This may convert this wetland from what we assume is currently a passive C storage area to an active source of greenhouse gases.

Pregnancy outcome in military and civilian women.

Physical and medical risk factors have long been linked to prematurity and intrauterine growth retardation. Recently, out-of-home employment has been cited as an additional risk. The primary objective of this investigation was to compare pregnancy risks and birth outcome in two groups of employed women (one military and one civilian). We performed a prenatal survey and a postpartum chart review and found that active duty military women worked longer into pregnancy and reported lower levels of social support than their civilian counterparts. However, infant weight and gestational age were not significantly different in the two groups.

Forest and woodland depletion in the Lake Elementeita Basin, Kenya.

PIP: Research geographers combined LANDSAT imagery analysis and vegetation survey (LANDSAT data interpretation, ground truthing, and quantitative transect sampling) to study the spatial dynamics of forest and woodland areas in the Lake Elementeita watershed in the central Rift Valley of Kenya. Between 1973-1984, trees in forests and woodlands disappeared rapidly from a cover of 152-64 sq. km, i.e. 45-19% of total catchment. The most rapid decrease occurred between 1973-1976 which was associated with immigration into the area in the 1960s and 1970s. Indeed the annual population growth rate in the area was 5.7%. Further most of the population concentrated in the upper and middle catchment areas of Ndunduri, Ngorika, and Nyaituga where the soils and climate were best for commercial crop and livestock farming. This high concentration of people in 1 area along with the high population growth rate contributed greatly to deforestation. In fact, it resulted in a 57.9% loss of total forest and woodland areas. These trees used to cover most of the Ndunduri and Ngorika areas. Agroecosystems have replaced the Juniperus procera and Olea africana forest belts which dominated the Ngorika plains in the past. Further, in 1988, field observations revealed that very limited forest and woodland areas have remained undisturbed. Based on these results and the fact that little substantial efforts towards conservation and afforestation, the researchers predicted that most of the watershed would be with forests and woodlands by 2000. They further noted that deforestation could cause lower water levels in Lake Elementeita, especially during droughts, and worsen soil erosion. Therefore the government should initiate environmental controls in this watershed that match local conditions and the true and increasing needs of the rural population.^ieng