Microscopic evidence for Mn-induced long range magnetic ordering in MAX phase compounds.

Zero and low field nuclear magnetic resonance measurements have been performed on MAX phase samples (Cr1-x Mn x )2AC with A = Ge and Ga in order to obtain local microscopic information on the nature of magnetism in this system. Our results unambiguously provide evidence for the existence of long-range magnetic order in (Cr0.96Mn0.04)2GeC and for (Cr0.93Mn0.07)2GaC, but not for (Cr0.97Mn0.03)2GaC. We point to a possible dependence of long range magnetic order in these MAX phase compounds on the A atom.

Magnetic properties of (Fe1-xMnx)2AlB2 and the impact of substitution on the magnetocaloric effect.

In this work, we investigate the magnetic structures of (Fe1-xMnx)2AlB2 solid-solution quaternaries in the x=0 to 1 range using x-ray and neutron diffraction, magnetization measurements, and mean-field theory calculations. While Fe2AlB2 and Mn2AlB2 are known to be ferromagnetic (FM) and antiferromagnetic (AFM), respectively, herein we focused on the magnetic structure of their solid solutions, which is not well understood. The FM ground state of Fe2AlB2 becomes a canted AFM at x≈0.2, with a monotonically diminishing FM component until x≈0.5. The FM transition temperature (TC) decreases linearly with increasing x. These changes in magnetic moments and structures are reflected in anomalous expansions of the lattice parameters, indicating a magnetoelastic coupling. Lastly, the magnetocaloric properties of the solid solutions were explored. For x=0.2 the isothermal entropy change is smaller by 30% than it is for Fe2AlB2, while the relative cooling power is larger by 6%, due to broadening of the temperature range of the transition.

Liquid structure and temperature invariance of sound velocity in supercooled Bi melt.

Structural rearrangement of liquid Bi in the vicinity of the melting point has been proposed due to the unique temperature invariant sound velocity observed above the melting temperature, the low symmetry of Bi in the solid phase and the necessity of overheating to achieve supercooling. The existence of this structural rearrangement is examined by measurements on supercooled Bi. The sound velocity of liquid Bi was measured into the supercooled region to high accuracy and it was found to be invariant over a temperature range of ∼60°, from 35° above the melting point to ∼25° into the supercooled region. The structural origin of this phenomenon was explored by neutron diffraction structural measurements in the supercooled temperature range. These measurements indicate a continuous modification of the short range order in the melt. The structure of the liquid is analyzed within a quasi-crystalline model and is found to evolve continuously, similar to other known liquid pnictide systems. The results are discussed in the context of two competing hypotheses proposed to explain properties of liquid Bi near the melting: (i) liquid bismuth undergoes a structural rearrangement slightly above melting and (ii) liquid Bi exhibits a broad maximum in the sound velocity located incidentally at the melting temperature.

Carboxypeptidase E: a negative regulator of the canonical Wnt signaling pathway.

Aberrant activation of the canonical Wnt signal transduction pathway is involved in many diseases including cancer and is especially implicated in the development and progression of colorectal cancer. The key effector protein of the canonical Wnt pathway is ß-catenin, which functions with T-cell factor/lymphoid enhancer factor to activate expression of Wnt target genes. In this study, we used a new functional screen based on cell survival in the presence of cDNAs encoding proteins that activate the Wnt pathway thus identifying novel Wnt signaling components. Here we identify carboxypeptidase E (|CPE) and its splice variant, ΔN-CPE, as novel regulators of the Wnt pathway. We show that whereas ΔN-CPE activates the Wnt signal, the full-length CPE (F-CPE) protein is an inhibitor of Wnt/ß-catenin signaling. F-CPE forms a complex with the Wnt3a ligand and the Frizzled receptor. Moreover, F-CPE disrupts disheveled-induced signalosomes that are important for transducing the Wnt signal and reduces ß-catenin protein levels and activity. Taken together, our data indicate that F-CPE and ΔN-CPE regulate the canonical Wnt signaling pathway negatively and positively, respectively, and demonstrate that this screening approach can be a rapid means for isolation of novel Wnt signaling components.

On the structure of aragonite.

High-resolution synchrotron powder diffraction measurements were carried out at the 32-ID beamline of the Advanced Photon Source of Argonne National Laboratory in order to clarify the structure of geological aragonite, a widely abundant polymorph of CaCO(3). The investigated crystals were practically free of impurity atoms, as measured by wavelength-dispersive X-ray spectroscopy in scanning electron microscopy. A superior quality of diffraction data was achieved by using the 11-channel 111 Si multi-analyzer of the diffracted beam. Applying the Rietveld refinement procedure to the high-resolution diffraction spectra, we were able to extract the aragonite lattice parameters with an accuracy of about 20 p.p.m. The data obtained unambiguously confirm that pure aragonite crystals have orthorhombic symmetry.

Balloon cervical ripening with extra-amniotic infusion of saline or prostaglandin E2: a double-blind, randomized controlled study.

OBJECTIVE: To compare extra-amniotic infusion of diluted prostaglandin (PG) E2 solution with saline infusion in balloon cervical ripening and labor induction. METHODS: Women with pregnancy complications and Bishop scores of 3 or lower (n = 116) were assigned randomly to receive extra-amniotic infusion (1 mL/minute) of normal saline or PGE2 in saline (0.5 microg/mL) through a Foley catheter with a 30-mL inflated balloon. We induced labor using intravenous oxytocin only when labor had not developed by 6 hours after balloon expulsion. Analysis was by intent-to-treat. We assessed ripening efficiency and course of labor in women who had spontaneous balloon expulsion (n = 110) and trial of labor (n = 107), respectively. RESULTS: Ripening with PGE2 was associated with significantly shorter mean (+/- standard error of the mean [SEM]) time for balloon expulsion (4.7 +/- 0.4 versus 6.5 +/- 0.6 hours) and with significantly higher Bishop scores (P <.002), compared with ripening with saline. In the PGE2 group, rates of labor induction (15%) and oxytocin use (37%) were significantly lower than in the saline group (51% and 72%, respectively). The groups did not differ significantly in other labor abnormalities, labor duration, mode of delivery, birth weight, Apgar scores, and puerperal morbidity. CONCLUSION: Cervical ripening by extra-amniotic balloon and PGE2 infusion is faster and more effective than by balloon and saline infusion, resulting in a higher rate of spontaneous labor and a lower rate of oxytocin use.

Image magnification does not contribute to the repeatability of caliper placement in measuring nuchal translucency thickness.

The objective of this study was to assess whether nuchal translucency image magnification contributes to the repeatability of caliper placement. Twenty-seven women undergoing first-trimester ultrasound screening at 11-14 weeks were examined by two qualified examiners. Fetal nuchal translucency thickness was measured twice by each examiner on a regular-sized image and subsequently on the same still image magnified. Intraobserver repeatability coefficients of the regular-sized images were 0.28 mm and 0.34 mm for examiners A and B, respectively. Identical intraobserver repeatability coefficients of 0.28 mm were attained for both examiners on the magnified images. Interobserver repeatability of regular-sized image measurements showed a significant difference (p < 0.01) but the mean difference (+/- standard deviation) of 0.10 (0.18) mm was negligible. Similarly, interobserver repeatability of the magnified-image measurements yielded a significant difference (p < 0.02), but again with a small mean difference of 0.13 (0.26) mm. There were also significant differences when regular-sized images and magnified images were compared for both examiners: 0.08 (0.16) mm for examiner A (p < 0.02) and 0.10 (0.17) mm for examiner B (p < 0.01). Our results demonstrate that nuchal translucency image magnification does not contribute to the reproducibility of the measurement. Despite significantly smaller mean values obtained from the magnified images, compared to the regular-sized measurements, those differences do not justify modification of the criteria for caliper placement on magnified images. Blind repeated measurements on a regular-sized and/or magnified image are recommended as a tool for self-assessment, quality control and training.

A comparison of clinical and ultrasonic estimation of fetal weight.

OBJECTIVE: To compare the accuracy of routine ultrasonic and clinical birth weight estimation. METHODS: The study sample included 1717 women with singleton pregnancies, admitted in early labor with an ultrasonic estimated fetal weight (EFW) performed during the preceding week. Clinical EFW was obtained before rupture of the membranes by the attending senior resident, who was unaware of the ultrasonic EFW. Accuracy was determined by the percentage error, the absolute percentage error, and the proportion of estimates within 10% of the actual birth weight (birth weight +/- 10%). Statistical analysis was done by the paired t test, the comparison of correlated variances, the Wilcoxon sign test, and the chi2 test. Actual birth weight in the study sample averaged 3334+/-607 g (+/- standard deviation, [SD]) and ranged between 690 and 5320 g. RESULTS: The means of all error terms of the clinical EFW were significantly smaller than those of the ultrasonic EFW. However, the rates of estimates within 10% of birth weight were not significantly different (72 and 69%, respectively). In birth weights less than 2500 g, both methods overestimated the birth weight, but the mean errors of the ultrasonic EFW were significantly smaller than those of the clinical EFW. The ultrasonic EFW had significantly higher rates of birth weight +/- 10% than the clinical EFW (63 compared to 49%, respectively). In the 2500-4000 g birth weight, only the clinical EFW had no systematic error, whereas the ultrasonic EFW underestimated the birth weight. The mean errors of the clinical EFW were significantly smaller and the rate of birth weight +/- 10% significantly higher than those of the ultrasonic EFW. In the birth weight greater than 4000 g, both methods underestimated the birth weight, and the mean errors and the rate of estimates within 10% of birth weight were similar for both methods. CONCLUSION: Clinical estimation of birth weight in early labor is as accurate as routine ultrasonic estimation obtained in the preceding week. In the lower range of birth weight (less than 2500 g), ultrasonic estimation is more accurate; in the 2500-4000 g range, clinical estimation is more accurate. In the higher range of birth weight (greater than 4000 g), both methods have similar accuracy.

Nuchal translucency audit: a novel image-scoring method.

OBJECTIVE: The aim of this study was to evaluate the feasibility and reproducibility of a novel image-scoring method of first-trimester nuchal translucency measurement as an objective tool of ongoing audit and training. DESIGN: This was an independent evaluation of nuchal translucency images by three separate reviewers unaware of the examiner. SUBJECTS: There were 105 consecutive singleton pregnancies undergoing first-trimester screening. METHODS: Each image was scored according to the following criteria: section (oblique, 0; mid-sagittal, 2), caliper placing (misplaced, 0; proper, 2), skin line (nuchal only, 0; nuchal and back, 2), image size (unsatisfactory, 0; satisfactory, 1), amnion (not visualized, 0; visualized, 1) and head position (flexion/hyperextension, 0; straight, 1). The final score was categorized into one of four quality groups: excellent (8-9), reasonable (4-7), intermediate (2-3), unacceptable (0-1). RESULTS: The distributions of the four quality groups were similar between the three reviewers: 11.4% were classified as excellent, 57.1% as reasonable, 25.7% as intermediate and 5.7% as unacceptable. Inter-reviewer agreement showed identical classification, by each pair of reviewers, from 65.7% to 74.3%, and partial agreement to neighboring quality groups from 25.7% to 34.3% of the cases. In none of the cases did the reviewers differ in categorizing cases to remarkably different quality groups. Application of the auditing method to the examiners showed similar distribution to the various quality groups and similar mean final score of 4.69 (0.39, SE), 4.54 (0.15, SE) and 4.65 (0.15, SE). CONCLUSIONS: The described image-scoring method represents a new approach towards the evaluation of ultrasound performance as a whole and nuchal translucency measurement in particular. It may be employed by every center in an independent manner with minimal resources and regardless of the method of risk assessment. More studies will be needed to determine the standards required from the examiners and to elucidate the contribution of the proposed auditing method to the examination's quality and the process of training.

Chorioamnionitis caused by gram-negative bacteria as an etiologic factor in preterm birth.

The role and microbiological causes of infection and inflammation of the chorioamnion were studied in 85 patients with spontaneous preterm deliveries (< 37 weeks) and in 85 control patients with full term deliveries. Microorganisms were isolated from the freshly separated chorioamnion in 55% of preterm and 26% of term deliveries (p < 0.001). Isolation rates of gram-negative enteric bacteria were significantly higher in preterm deliveries than in term deliveries (p < 0.001), whereas differences in the isolation of other bacterial species were not significant. Histological chorioamnionitis was noted in 49% of preterm and 14% of term deliveries (p < 0.001), and was strongly associated with a positive chorioamniotic culture in both groups (p < 0.001). Histological chorioamnionitis was noted in 94%, 54%, and 4% of membranes with gram-negative rods, other microbial species and negative cultures, respectively (p < 0.001). Preterm deliveries were also associated with significantly higher rates of bacterial vaginosis (38% vs. 14%) and isolation of vaginal pathogens (85% vs. 65%). In the case of the majority (88%) of chorioamniotic isolates the same species was isolated in the vagina. The findings suggest that gram-negative enteric rods are important placental pathogens responsible for sub-clinical chorioamnionitis and possibly preterm birth. The findings support the concept that microorganisms ascending from the lower genital tract produce local inflammation, which may result in preterm labour and delivery.

Ripening of the unfavorable cervix with extraamniotic catheter balloon: clinical experience and review.

The use of an extraamniotic catheter balloon, inflated above the internal cervical os, has been advocated as a nonpharmacological, mechanical method of cervical ripening before induction of labor. Additional measures may include applying traction on the catheter, or the infusion of normal saline (1 ml/min) via the catheter's port into the extraamniotic space. The results of catheter balloon cervical ripening are reviewed from 13 published reports and a departmental series of 190 pregnancies with unfavorable cervix, encompassing nearly 1000 patients. A mean change in cervical score of at least 3 points, was noted in most studies after balloon expulsion or removal. The present series and other studies suggest that oxytocin use for induction and/or augmentation of labor is increased after balloon ripening, compared with its use in spontaneous labor or after cervical ripening by prostaglandins. In 11 studies, catheter balloon ripening was compared with cervical ripening by other mechanical, or pharmacological (i.e., oxytocin or prostaglandins) methods. Of these, eight were prospective and randomized-controlled and three were case-controlled studies. It is suggested that ripening efficacy by catheter balloon is similar, or better, than other methods; but there is no significant difference in the mode of delivery or perinatal outcome. This review also suggests that cervical ripening with extraamniotic catheter balloon has the advantages of simplicity, low cost, reversibility, and lack of systemic or serious side effects.

Abortion at 18-22 weeks by laminaria dilation and evacuation.

OBJECTIVE: To evaluate the complications of late second-trimester abortions (18-22 weeks) by laminaria dilation and evacuation, and the obstetric outcome of subsequent pregnancies. METHODS: Dilation of the cervix was achieved by repeated laminaria tent replacement. Evacuation was carried out in the outpatient clinic using general anesthesia. After the first menstrual period, all patients were invited for examination and thereafter were asked to report the outcome of subsequent pregnancies. RESULTS: One hundred seventy-one late second-trimester abortions were performed. Cervical dilation was satisfactory in 158 women (92%). Operative sonography was required in nine (5%) women. One had uterine atony. Follow-up from 150 (88%) women indicated no infection, but one woman required repeat curettage for retained products of conception. There was no indication of cervical injury on cervical internal os measurements remote from abortion. Of the 50 patients who conceived and elected to continue the subsequent pregnancies, two had premature deliveries unrelated to cervical incompetence, and all others reached term. CONCLUSION: Late second-trimester termination by laminaria dilation and evacuation is safe and probably not associated with future adverse pregnancy outcome.

Sonographic assessment of cervical changes during pregnancy and delivery: current concepts.

Correct detection of premature contractions and incompetent uterine cervix is still a challenging obstetrical problem since these factors remain a major cause of perinatal loss. Ultrasonography offers additional important data for the prediction of these pathologies which have common sonographic patterns; shortening of the cervical length, funneling of the membranes and dilatation of the endocervical canal. The first section of this review highlights sonography of normal cervical anatomy, while the second section focuses on recent advances in sonographic detection of premature contractions and incompetent cervix. It is believed that due to its accuracy and reproducibility, this noninvasive technique should become more integrated into this aspect of antenatal care.

Intravenous immunoglobulin treatment of pregnant patients with unexplained recurrent abortions.

Intravenous immunoglobulins, first given to recurrent aborters with anti-phospholipid syndrome, have been administered to unexplained aborters since 1986. They probably have immunomodulatory properties beyond supplying blocking antibodies. When pregnancy was confirmed, women were started with a loading dose which was repeated every 3-4 weeks until the second trimester. Dosages were empirical. Pregnancy rates ranged between 50 and 82%. The main maternal complications, i.e. allergic reactions and infections, were rare.

Immunosuppressive effect of uterine fluid on spermatozoa-stimulated mixed lymphocyte cultures.

Spermatozoa, obtained from 20 healthy individuals, were incubated with crude uterine fluid or with a purified IgG fraction obtained from uterine fluid before adding them to cultures with allogeneic lymphocytes. Untreated spermatozoa induced a proliferative 1.5- to 6-fold increase, while the spermatozoa treated with crude uterine fluid or with purified IgG fraction caused 84-100% suppression of lymphocyte blastogenesis. These results suggest the existence of an endogenous uterine fluid factor, apparently IgG, which causes inhibition of lymphocyte proliferation induced by spermatozoa in the uterine lumen.

Continence mechanism after colpo-needle suspension for stress urinary incontinence.

OBJECTIVE: To determine the mechanism by which continence is restored following the colpo-needle suspension procedure. STUDY DESIGN: During 1990-1991, 37 women underwent colpo-needle suspension for stress urinary incontinence. Urodynamic investigation was performed preoperatively and 6-12 months postoperatively, and the results of these tests were compared in order to define the changes that might be responsible for the restoration of continence. RESULTS: In comparing the preoperative and postoperative cystometric and uroflowmetric measurements, we found no significant differences in the values for bladder capacity, residual volume pressure rise on filling or standing, maximal urethral voiding pressure or peak flow rates. The urethral pressure profiles at rest did not result in statistically significant differences regarding urethral length or urethral pressure. The only such differences postoperatively were elevation of pressure. Transmission ratios on coughing and in the proximal half of the urethra were Q1, 100.3 (P < .001), and Q2, 100.4 (P < .002), respectively. CONCLUSION: Colposuspension appears to correct genuine stress incontinence by repositioning the proximal urethra in the intraabdominal pressure zone, causing restoration of positive pressure transmission to the proximal urethra.

Conservative management of interstitial pregnancy using operative laparoscopy.

Interstitial pregnancy has been treated so far mainly by either resection of the cornu or hysterectomy. In this article, two patients with cornual pregnancy were operated upon laparoscopically with an uneventful postoperative recovery. This laparoscopic treatment is simple, does not require extensive operative laparoscopic expertise, and is relatively short and less expensive than laparotomy. We suggest that laparoscopic conservative repair be used to replace cornual resection by laparotomy or hysterectomy in cases of early diagnosed interstitial pregnancy.

Investigation of the uterine cavity in recurrent aborters.

To prospectively compare the diagnostic ability of both HSG and diagnostic hysteroscopy in recurrent aborters, an HSG followed by a diagnostic hysteroscopy was performed in 106 patients during an investigation into recurrent abortions. The uterine cavity findings on HSG and at hysteroscopy were compared. Among the 60 abnormal HSG patients, intrauterine pathology was demonstrated in 37 (34.9%). Among the 46 normal HSG patients, a normal uterine cavity was found in 33 (31.3%). The sensitivity of the HSG in revealing intrauterine abnormalities was therefore 79% and its specificity 60%. In 23 pathologic HSG, no abnormalities were seen by hysteroscopy. In 13 cases, hysteroscopy demonstrated mild intrauterine findings overlooked by HSG. The false-positive rate was 38% and the false-negative rate was 28%. Hysterosalpingography showed a high false-positive rate, especially in the intrauterine adhesions group. In view of the low specificity and high false-positive and false-negative rates, we believe that hysteroscopic evaluation of the uterine cavity is superior to HSG in recurrent abortions.

Safety of midtrimester pregnancy termination by laminaria and evacuation in patients with previous cesarean section.

OBJECTIVE: The objective of this study was to retrospectively assess whether there was an increased perioperative risk in midtrimester pregnancy termination by laminaria and evacuation associated with a previous uterine scar. STUDY DESIGN: From 1978 to 1993 1064 patients underwent midtrimester (14 to 22 weeks) pregnancy termination by means of laminaria and evacuation. Of these, 70 patients had a previous uterine scar and are the subjects of this study. RESULTS: There were no major operative complications, such as anesthetic complications, perforations, or cervical lacerations, in the entire series. Mean operative time (minutes) for induced abortion was statistically similar in the unscarred compared with the scarred uteri groups (8.03 +/- 4.40 vs 7.46 +/- 4.42, respectively) and was statistically different when the indication for evacuation was missed abortion (6.08 +/- 1.86 vs 4.81 +/- 2.11, respectively; p < 0.005). This difference in operative time could be explained by the number of laminaria tents used in each group. Atony with hemorrhage occurred in two patients who underwent induced abortion, and disseminated intravascular coagulation occurred in eight missed abortion cases, but none had scarred uterus. CONCLUSION: Previous cesarean section scar does not seem to increase the perioperative risk of late termination (14 to 22 weeks) by the laminaria and evacuation technique.

PIP: Obstetrician-gynecologists at Assaf Harofeh Medical Center in Zerifin, Israel, performed 1064 midtrimester (14-22 weeks) pregnancy terminations between 1978 and 1993 by the laminaria and evacuation technique. Medical researchers wanted to determine whether the 70 (6.6%) patients with a previous Cesarean section faced an increased perioperative risk. None of the 70 women suffered any major complications (e.g., cervical lacerations). The mean operative time for women with a scarred uterus was not significantly different than that for those with an unscarred uterus (7.44 vs. 8 minutes). When the researchers examined only missed abortion cases, however, the mean operative time for women with a scarred uterus was significantly shorter than that for women with an unscarred uterus (4.8 vs. 6 minutes; p .005). Among missed abortion cases, more laminaria tents were needed in women with a scarred uterus than in those with an unscarred uterus (3.7 vs. 2.91; p .01), suggesting that the number of laminaria tents accounted for the difference in operative time. Among women with an unscarred uterus, 8 missed abortion cases had disseminated intravascular coagulation and 2 women experienced uterine atony with hemorrhage during the induced abortion. Except for those with disseminated intravascular coagulation, all the women were discharged from the hospital on the same day as the procedure. These findings show that laminaria and evacuation is a safe midtrimester pregnancy termination technique and that, since it requires only a few hours in an outpatient postoperative facility, it is also cost effective.