Comparación entre coinoculación con Bradyrhizobium japonicum y Azospirillum brasilense e inoculación simple con Bradyrhizobium japonicum en la nodulación, crecimiento y acumulación de N en el cultivo de soja Comparison of coinoculation with Bradyrhizobium japonicum and Azospirillum brasilense with inoculation with Bradyrhizobium japonicum on nodulation, growth, and N accumulation in the soybean crop

El objetivo fue comparar la coinoculación con Bradyrhizobium japonicum y Azospirillum brasilense con relación a la inoculación simple con Bradyrhizobium japonicum en la nodulación, crecimiento y acumulación de N en el cultivo de soja y su rendimiento. Se realizaron dos experimentos en lotes en los que nunca se cultivó soja en años con diferentes condiciones hídricas. Los tratamientos fueron: testigo (sin inoculación), coinoculación con Bradyrhizobium japonicum y Azospirillum brasilense e inoculación simple con Bradyrhizobium japonicum. La nodulación en ambos experimentos fue superior en la coinoculación, aunque hubo diferencias significativas en el experimento con déficit hídrico. Los rendimientos, en ambos experimentos, presentaron valores medios superiores en la coinoculación, aunque sin diferencias significativas. La acumulación de biomasa aérea y N fue mayor en el año húmedo. El porcentaje de N derivado de la fijación biológica de N en el cultivo en el año seco fue de 26% para la inoculación simple y de 30% en la coinoculación, mientras que en el año húmedo este porcentaje fue de 41 y 47% respectivamente. A partir de estos resultados se concluye que existe un efecto de estimulación del crecimiento del cultivo de soja por la coinoculación. Sin embargo, es necesario continuar con estudios sobre este tema.The aim of this study was to compare coinoculation with Bradyrhizobium japonicum and Azospirillum brasilense with inoculation with Bradyrhizobium japonicum on nodulation, growth, and N accumulation in the soybean crop in field conditions. Two field tests were carried out for two years with different hydric conditions in areas not previously cultivated with soybean. The treatments were: control, coinoculation using Bradyrhizobium japonicum + Azospirillum brasilense and inoculation with Bradyrhizobium japonicum. Nodulation in both experiments was increased by dual inoculation, although significant differences were registered in the experiment with water deficiency. In both experiments, in coinoculation treatments yield mean values were higher than other treatment, although no significant differences were found. Biomass and N accumulation by the crop was higher in the coinoculated treatment than in the simple inoculation in the wet year. In the dry-condition year, N derived from the biological fixation was 26% in the simple application and 30% in the coinoculation treatment and in the year without water deficit, these percentages were 41 and 47 % respectively. From these results we conclude that coinoculation has a positive effect of growth stimulation in soybean crops. However, we believe it is necessary to continue studying this subject further

Comparación entre coinoculación con Bradyrhizobium japonicum y Azospirillum brasilense e inoculación simple con Bradyrhizobium japonicum en la nodulación, crecimiento y acumulación de N en el cultivo de soja

El objetivo fue comparar la coinoculación con Bradyrhizobium japonicum y Azospirillum brasilense con relación a la inoculación simple con Bradyrhizobium japonicum en la nodulación, crecimiento y acumulación de N en el cultivo de soja y su rendimiento. Se realizaron dos experimentos en lotes en los que nunca se cultivó soja en años con diferentes condiciones hídricas. Los tratamientos fueron: testigo (sin inoculación), coinoculación con Bradyrhizobium japonicum y Azospirillum brasilense e inoculación simple con Bradyrhizobium japonicum.La nodulación en ambos experimentos fue superior en la coinoculación, aunque hubo diferencias significativas en el experimento con déficit hídrico. Los rendimientos, en ambos experimentos, presentaron valores medios superiores en la coinoculación, aunque sin diferencias significativas. La acumulación de biomasa aérea y N fue mayor en el año húmedo. El porcentaje de N derivado de la fijación biológica de N en el cultivo en el año seco fue de 26% para la inoculación simple y de 30% en la coinoculación, mientras que en el año húmedo este porcentaje fue de 41 y 47% respectivamente. A partir de estos resultados se concluye que existe un efecto de estimulación del crecimiento del cultivo de soja por la coinoculación. Sin embargo, es necesario continuar con estudios sobre este tema

Almacenamiento de muestras de suelo: incidencia sobre la cuantificación de biomasa microbiana

La forma en que se conserva la muestra influye sobre la determinación de biomasa microbiana. Se evaluó el efecto de distintas formas de almacenamiento sobre el C y N de la biomasa microbiana (C-BM, N-BM) y sobre el cociente metabólico (qCO2). Los tratamientos fueron: refrigeración a 4 °C, congelamiento a -12°C (con posterior preincubación y sin ésta) y muestra fresca recién extraída. Los sitios muestreados fueron: rastrojo de soja (R), monte de eucaliptos (E), invernáculo hortícola (I), pastura (P) y monte nativo (M). Las repeticiones de cada sitio fueron tres. En R, I, P y M los tratamientos no ocasionaron variaciones en C-BM. La refrigeración a 4 °C no alteró los valores de N-BM ni el qCO2 en R, I, P y M. Los coeficientes de correlación entre el C-BM y el N- BM de muestras frescas y muestras refrigeradas a 4 °C fueron de 0,65 y 0,94 respectivamente. La estimación del N inmovilizado a partir de N-BM de muestras refrigeradas a 4 °C tuvouna variación de ± 7% respecto de las muestras frescas. Se concluyó que el almacenamiento de muestras a 4 °C es el más adecuado para medir C-BM y N-BM porque reflejan de mejor manera la condición del suelo sin almacenar

Asymptomatic Complete Placenta Previa: A Case Report and Review of Literature

Abstract We present a case of a stable and asymptomatic complete placenta previa for all the duration of pregnancy in a 40-year-old woman, treated with an elective cesarean section at 37 weeks of gestational age. Placenta previa is a condition derived from an abnormal implantation of the embryos in the lower uterine segment. Risk factors for the development of placenta previa include prior cesarean delivery, pregnancy termination, intrauterine surgery, smoking, multi-fetal gestation, increasing parity, maternal age and the rising rates of cesarean section. Usually complete placenta previa becomes symptomatic in third trimester of gestational age and it is associated with adverse consequences for both mother and children, such as intra-uterine growth restriction, preterm birth, antenatal and intra-partum hemorrhage, maternal blood transfusion and emergency hysterectomy. In this article we performed a review the international literature of the last twenty years of similar cases, emphasizing on the aspects of the management and time of delivery in patient with placenta previa, and in particular we focus on the management of stable and asymptomatic cases. On the basis of our experience, the risks for both mother and fetus and the results of the literature, we conclude that in presence of a stable and asymptomatic complete placenta previa an early term birth (ETB) at 37 weeks of gestational age, rather than a late preterm birth (LPTB) between 34-37 weeks, is a more appropriate time of delivery, and it is associated to a better prognosis for both mother and child. Keywords Placenta Previa, Hemorrhage, Caesarean Section, Lower Uterine Segment Background Antepartum hemorrhage complicates 2-5% of pregnancies, which approximately one-third is due to placenta previa, a condition derived to an abnormal implantation of the embryos in the lower uterine segment ▪ Partial: the placenta covers partly the intern cervical os. ▪ Complete: the placenta covers completely the intern cervical os It is estimated placenta previa has been diagnosed increasingly in recent decades, due mostly to the widespread use of ultrasound to occur in between 0.2 and 0.3% of third-trimester pregnancies. False-positive diagnoses are common in the second trimester and the term "potential placenta previa" is used to describe this situation Case Report A 40-year-old woman with three pregnancies, two previous miscarriages at 7 and 8 weeks of gestational age in the past two years, was admitted in our institute at 37 weeks. She weighed 71 Kg and was tall 170 cm. She was heterozygous for the mutation G1691A for the gene of Leiden's factor and homozygous for the mutation C677T of MTHFR's gene. She was treated with levotiroxin 50 mg for the presence of multiple thyroid nodules. In the second trimester the routine ultrasound suspected a complete placenta previa, subsequently confirmed at the transvaginal ultrasound performed at the third trimester by the presence of a placental edge overlapping the internal os (complete placenta previa) (Picture 1). The cervical length was >30mm. For all the pregnancy long the patient was stable and asymptomatic. During pregnancy the patient was treated with acetyl salicylic acid (suspended two days before the delivery), prenatal vitamins, and with antenatal corticosteroids (betamethasone 4 mg). Picture 1. ultrasonographic image of the complete placenta previa at 33 weeks of gestational age Since the diagnosis of complete placenta previa and the stable condition of the patient (no vaginal bleeding, no uterine contraction, WBC 12.5^3/uL, RBC 3.82 10^6/uL, Hb 10.9 g/dL, HCT 33.4%, PLT 237 10^3/uL), informing her and the family of the possible risks for mother and infant, we decided to schedule a cesarean delivery at 37 weeks in our tertiary care center. After the loco-regional anesthesia, the surgical team performed a Cesarean section through a transverse skin incision and through the lower segment of the uterus (Pictures 2-3). Since the placenta was anterior, the surgeon incised it to deliver the baby. The women gave birth to a healthy female infant (APGAR score 10), weight 2925 gr. Picture 2. lower uterine segment previous the incision During the incision and upon the manual removal of the placenta, there was an important blood loss, so the surgical team exerted an external mechanical compression of the lower uterine segment to ensure haemostasis after checking for residual placental tissue on the area of placental insertion, utero-tonic drugs were also administered. Due to the blood loss, a blood gas was obtained intraoperatively, since haemoglobin (Hb) was 7.9 g/dL anesthesiologist and surgeon decided to transfuse a unit of packed red blood cells. Diagnosis and Management Although around 5% of women have ultrasound evidence of a low placenta at 16 to 18 weeks, only 10% of this 5% (i.e. 0.5% overall) actually have a placenta previa at delivery. The apparent change of placental position results from formation of the lower uterine segment A conclusive diagnosis of complete placenta previa is ascertained sonographically in the third trimester, when upward migration from the internal cervical os becomes unlikely A placental edge exactly reaching the internal os is described as 0 mm. When the placental edge reaches or overlaps the internal os on transvaginal sonogram (TVS) between 18 and 24 weeks' gestation (incidence 2-4%), a follow-up examination for placental location in the third trimester is recommended. Overlap of more than 15 mm is associated with an increased likelihood of placenta previa at term (ll-2A). When the placental edge lies between 20 mm away from the internal os and 20 mm of overlap after 26 weeks' gestation, ultrasound should be repeated at regular intervals depending on the gestational age, distance from the internal os, and clinical features such as bleeding, because continued change in placental location is likely. Overlap of 20 mm or more at any time in the third trimester is highly predictive of the need for Caesarean section (CS) (llI-B). The os-placental edge distance on TVS after 35 weeks' gestation is valuable in planning route of delivery. When the placental edge lies > 20 mm away from the internal cervical os, women can be offered a trial of labor with a high expectation of success. A distance of 20 to 0 mm away from the os is associated with a higher CS rate, although vaginal delivery is still possible depending on the clinical circumstances (ll-2A). In general, any degree of overlap (> 0 mm) after 35 weeks is an indication for Caesarean section as the route of delivery (ll-2A). Outpatient management of placenta previa may be appropriate for stable women with home support, close proximity to a hospital, and readily available transportation and telephone communication (ll-2C). There is insufficient evidence to recommend the practice of cervical cerclage to reduce bleeding in placenta previa (llI-D). Regional anesthesia may be employed for CS in the presence of placenta previa (II-2B). Women with a placenta previa and a prior CS are at high risk for placenta accreta. If there is imaging evidence of pathological adherence of the placenta, delivery should be planned in an appropriate setting with adequate resources (II-2B) Bahar et al in 2009 conducted a retrospective study over a 10-year period from 1996 to the end of 2005 including 306 women presenting different types of placenta previa (PP). The authors compared risk factors and pregnancy outcome in different types of PP. The overall incidence of PP was 0.73%. Major PP (complete or partial) occurred in 173 women (56.5%) and minor PP (marginal PP pr low-lying placenta) in 133 women (43.5%). There were no differences between women with major and minor PP regarding age, parity, and previous miscarriages. After controlling for confounding factors, women with major PP showed a significantly higher incidence of antepartum hemorrhage (OR 3.18; 95% CI 1.58-6.4, P=0.001), placenta accreta (OR 3.2; 95% CI 1.22-8.33, P=0.017), and hysterectomy (OR 5.1; 95% CI 1.31-19.86, P=0.019). Antepartum hemorrhage in women with PP was associated with premature delivery (OR 14.9; 95% CI 4.9-45.1, P<0.001), more commonly in women with major PP. The only significant difference between women with major and minor PP regarding neonatal outcome was that major PP was associated with higher incidence of admission to the neonatal intensive care unit (P=0.014). They concluded that complete or partial placenta previa is associated with higher morbidity than minor PP. Even if placenta previa often requires iatrogenic preterm (PTB) <34 weeks because of maternal bleeding or spontaneous preterm labor, mostly because catastrophic bleeding can occur and is not predictable on the basis of clinical factors, there is also a good number of women that remain asymptomatic. In these cases clinicians must decide when to schedule cesarean delivery in a "stable" patient with placenta previa In their U.S. population-based study Ananth et al discovered that <34 weeks PTBs in women with placenta were only 16.9%, 27.5% women delivered between 34-37 weeks, and 55.6% occur ≥37 weeks Another important predicting factor in women with placenta previa is cervical length (CL). Fukushima et al Research in Obstetrics and Gynecology 2012, 11(3): 30-35 33 conducted a recent study on eighty uncomplicated, singleton pregnancies with an antenatal diagnosed of placenta previa. The aim of this study was to evaluate the relationship between cervical length (CL) and obstetrical outcomes in women with placenta previa. N=60 women had a CL ≥30 mm, n=20 women had a CL <30 mm. The mean CL was 38.5±5.4mm and 26.9±3.2mm and the mean gestational age at measurement was 29.2±2.7 and 28.5±2.7weeks of gestation for the longer and shorter CL groups, respectively. The median estimated blood loss at cesarean section (CS) was significantly higher in the shorter CL group (1302mL vs. 2139mL, P=0.023) as was the percentage of patients with massive intraoperative hemorrhage (60.0 vs. 18.3%, P=0.001). In the shorter versus longer CL patients, emergent CS before 37weeks (23.3 vs. 50.0%, P=0.046) and the percentage of patients with placental adherence (6.7 vs. 35.0%, P=0.004) were both significantly more frequent in the shorter CL group. The shorter CL was a risk factor both for massive estimated blood loss (≥2000mL) (odds ratio 6.34, 95% confidence interval 1.91-21.02, P≤0.01) and placental adherence (odds ratio 6.26, 95% confidence interval 1.23-31.87, P≤0.05) in the multivariate analysis The benefits of avoiding emergent delivery with earlier delivery must be weighed against the neonatal risks of iatrogenic prematurity. Although the absolute risk of death or long-term complications of prematurity with LPTB are extremely low, "softer" morbidities in these infants are common. McIntire DD et al noticed late preterm birth children have increased neonatal morbidity compared with birth at term. Respiratory distress, transient tachypnea, grades 1 or 2 intraventricular hemorrhage, sepsis work-ups, culture-proven sepsis, phototherapy for hyperbilirubinemia and intubation in the delivery room were significative more common in these infants Once a decision to perform cesarean delivery has been made, questions arise about the anesthesiological management. In 1999 Frederiksen et al Conclusions The debate regarding the optimal timing of delivery in women with complete placenta previa and, particularly, the management of the stable and asymptomatic complete placenta previa is still open. In the management of the present case on the basis of the following conclusions: 1) 36 weeks +0 were the best time to deliver in a patient with stable complete previa in the study of Zlatnik et al, but at 36 weeks the neonatal NICU admissions have a percentage of 22.1% and the need for mechanical ventilation 3%, compared to the respective percentage at 37 weeks, 11,8% and 1.1%. The neonatal mortality was similar in both groups (0,3% at 36 weeks and 0,2% at 37 weeks) 2) 38 weeks +0 were considered the best term to deliver in patient with stable previa and negative fetal lung maturity tests (PG or L/S ratio) at 37 weeks, but at 38 weeks the maternal morbidity is significantly higher than at 36 weeks (58.6% vs 15.0%) 3) absence of a previous cesarean section. A previous CS is significantly associated with risk of accretion. 4) presence of a cervical length >30 mm; On the basis of the following point we decided to choose for an early term birth (ETB) at 37 weeks of gestational age rather than a late preterm birth (LPTB). ACKNOWLEDGMENT