Detecting single base substitutions as heteroduplex polymorphisms

We have developed a sensitive technique for detecting single base substitutions in polymerase chain reaction (PCR) products from individuals heterozygous for polymorphisms or new mutations. This technique takes advantage of the formation of heteroduplexes in the PCR between different alleles from heterozygous individuals. These heteroduplexes can be detected on polyacrylamide gels because they migrate slower than their corresponding homoduplexes. Using PCR, we have generated a series of point mutations in a defined region of DNA in the equine infectious anemia virus (EIAV). Each mutation is the result of a single base substitution. By mixing the PCR products amplified from these mutations with one another, as well as with wildtype PCR products, we can generate heteroduplexes in which the identity of the mismatched bases is known. We detected eight of nine point mutations using this technique. We have also modified the electrophoretic conditions to optimize the detection of these heteroduplexes. In addition, the usefulness of this technique is demonstrated by its ability to detect a mutation in the cystic fibrosis gene that is the result of a single base substitution. This technique should prove useful for rapidly screening large numbers of individuals for new mutations or polymorphisms.

Respiratory assistance with a non-invasive ventilator (Bipap) in MND/ALS patients: survival rates in a controlled trial

Noninvasive ventilatory assistance, in ALS patients, with the bilevel intermittent positive air pressure (Bipap) was studied, in a prospective and controlled trial, by the authors. Twenty ALS bulbar patients, fulfilling El Escorial criteria for probable or definite disease, were selected. For the follow-up all patients were submitted to evaluation with the Norris scale, modified Barthel score and an analog scale of life satisfaction, every 3 months. All patients were also submitted to respiratory functional testing (RFT). Ten of these patients were treated with palliative management (group I), the remaining ten patients received Bipap support (group II). Clinical evolution curves and clinical parameters were not statistically different in both groups, except for the percentage of actual predicted value of vital capacity (p < 0.03), showing a more advanced disease in group II patients. Analog scale of life satisfaction showed improvement in the group II, even after the beginning of respiratory insufficiency, though without significance probably due to the small sample size (p < 0.1). Since 6 patients in group II are still alive survival rates were compared with log rank test considering cumulative survivals with Kaplan-Meier estimates. Total survival and survival from diurnal abnormalities in gas exchange (survival 1) were significantly longer for group II (p < 0.006 and p < 0.0004, respectively). In spite of the small number of patients, preliminary results strongly support the importance of BIPAP in ALS patients, though further studies must go on in order to optimize the best time for introducing Bipap.

Metabolomics analysis for biomarker discovery: advances and challenges

Over the last decades there has been a change in biomedical research with the search for single genes, transcripts, proteins, or metabolites being substituted by the coverage of the entire genome, transcriptome, proteome, and metabolome with the "omics" approaches. The emergence of metabolomics, defined as the comprehensive analysis of all metabolites in a system, is still recent compared to other "omics" fields, but its particular features and the improvement of both analytical techniques and pattern recognition methods has contributed greatly to its increasingly use. The feasibility of metabolomics for biomarker discovery is supported by the assumption that metabolites are important players in biological systems and that diseases cause disruption of biochemical pathways, which are not new concepts. In fact, metabolomics, meaning the parallel assessment of multiple metabolites, has been shown to have benefits in various clinical areas. Compared to classical diagnostic approaches and conventional clinical biomarkers, metabolomics offers potential advantages in sensitivity and specificity. Despite its potential, metabolomics still retains several intrinsic limitations which have a great impact on its widespread implementation - these limitations in biological and experimental measurements. This review will provide an insight to the characteristics, strengths, limitations, and recent advances in metabolomics, always keeping in mind its potential application in clinical/ health areas as a biomarker discovery tool.

International standards for early fetal size and pregnancy dating based on ultrasound measurement of crown-rump length in the first trimester of pregnancy

OBJECTIVES

There are no international standards for relating fetal crown-rump length (CRL) to gestational age (GA), and most existing charts have considerable methodological limitations. The INTERGROWTH-21(st) Project aimed to produce the first international standards for early fetal size and ultrasound dating of pregnancy based on CRL measurement.

METHODS

Urban areas in eight geographically diverse countries that met strict eligibility criteria were selected for the prospective, population-based recruitment, between 9 + 0 and 13 + 6 weeks' gestation, of healthy well-nourished women with singleton pregnancies at low risk of fetal growth impairment. GA was calculated on the basis of a certain last menstrual period, regular menstrual cycle and lack of hormonal medication or breastfeeding in the preceding 2 months. CRL was measured using strict protocols and quality-control measures. All women were followed up throughout pregnancy until delivery and hospital discharge. Cases of neonatal and fetal death, severe pregnancy complications and congenital abnormalities were excluded from the study.

RESULTS

A total of 4607 women were enrolled in the Fetal Growth Longitudinal Study, one of the three main components of the INTERGROWTH-21(st) Project, of whom 4321 had a live singleton birth in the absence of severe maternal conditions or congenital abnormalities detected by ultrasound or at birth. The CRL was measured in 56 women at < 9 + 0 weeks' gestation; these were excluded, resulting in 4265 women who contributed data to the final analysis. The mean CRL and SD increased with GA almost linearly, and their relationship to GA is given by the following two equations (in which GA is in days and CRL in mm): mean CRL = -50.6562 + (0.815118 × GA) + (0.00535302 × GA(2) ); and SD of CRL = -2.21626 + (0.0984894 × GA). GA estimation is carried out according to the two equations: GA = 40.9041 + (3.21585 × CRL(0.5) ) + (0.348956 × CRL); and SD of GA = 2.39102 + (0.0193474 × CRL).

CONCLUSIONS

We have produced international prescriptive standards for early fetal linear size and ultrasound dating of pregnancy in the first trimester that can be used throughout the world.

Relationship between cell surface carbohydrates and intrastrain variation on opsonophagocytosis of Streptococcus pneumoniae

Streptococcus pneumoniae undergoes spontaneous phase variation between a transparent and an opaque colony phenotype, the latter being more virulent in a murine model of sepsis. Opaque pneumococci have previously been shown to express lower amounts of C polysaccharide (cell wall teichoic acid) and in this study were shown to have a higher content of capsular polysaccharide by immunoelectron microscopy. This report then examined the relationship between expression of these two cell surface carbohydrate structures and their relative contribution to the increased virulence of opaque variants. Comparison of genetically related strains showed that the differential content of capsular polysaccharide did not affect the amount of teichoic acid as measured by a capture enzyme-linked immunosorbent assay (ELISA). In contrast, when the teichoic acid structure was altered by replacing choline in the growth medium with structural analogs, the quantity of capsular polysaccharide as measured by a capture ELISA was decreased, demonstrating a linkage in the expression of the two surface carbohydrate structures. A standardized assay was used to assess the relative contribution of cell surface carbohydrates to opsonophagocytosis. The opaque variants required 1.2- to 30-fold more immune human serum to achieve 50% opsonophagocytic killing than did related transparent variants (types 6B and 9V). The opsonophagocytic titer was proportional to the quantity of capsular polysaccharide rather than teichoic acid. The major factor in binding of the opsonin, C-reactive protein (CRP), was also the amount of capsular polysaccharide rather than the teichoic acid ligand. Only for the transparent variant (type 6B), which bound more CRP, was there enhanced opsonophagocytic killing in the presence of this serum protein. Increased expression of capsular polysaccharide, therefore, appeared to be the major factor in the decreased opsonophagocytic killing of opaque pneumococci.

Epicardial adipose tissue is an independent predictor of coronary atherosclerotic burden

INTRODUCTION

Epicardial adipose tissue (EAT) may play an active role in the development of coronary artery disease (CAD). The aim of this work was to study the relations between EAT, abdominal visceral fat (AVF), and coronary atherosclerotic burden as assessed by multislice computed tomography (MSCT).

POPULATION AND METHODS

Two hundred fifteen patients without known CAD referred to 64-SCT during a 6-months period were included. All patients underwent a standardized protocol including quantification of AVF, EAT, coronary artery calcification (CAC), and coronary angiography by MSCT.

RESULTS

Two hundred fifteen patients, with mean age of 58 ± 11 years, in which 61% were males, with mean body mass index (BMI) of 28 ± 4 kg/m(2) were included. EAT volume was directly associated with male sex, age, BMI, abdominal circumference, AVF, number of coronary segments with atherosclerotic plaques (p<0.01 for all), number of segments with significant stenoses, and presence of metabolic syndrome components (p<0.05). CAC increased by 14.7% per additional 10 ml of EAT volume. Adjusting for age, gender, and AVF changed this increase to 7.5%. After adjusting for all considered confounders, there was still an independent association, with a CAC increase of 3.7% per additional 10 ml of EAT. A significant interaction was found between EAT volume and gender and between EAT volume and obesity: an increase of EAT was associated with an increase of additional 8% of CAC in men, and additional increase of 5% in non-obese individuals (p<0.001 for both).

CONCLUSION

EAT volume positively relates to coronary atherosclerotic burden, as assessed by CAC; this correlation was shown to be independent of AVF.

Mutation rates at Y chromosome specific microsatellites

A collaborative work was carried out by the Spanish and Portuguese ISFG Working Group (GEP-ISFG) to estimate Y-STR mutation rates. Seventeen Y chromosome STR loci (DYS19, DYS385, DYS389I and II, DYS390, DYS391, DYS392, DYS393, DYS437, DYS438, DYS439, DYS460, DYS461, DYS635 [GATA C4], GATA H4, and GATA A10) were analyzed in a sample of 3,026 father/son pairs. Among 27,029 allele transfers, 54 mutations were observed, with an overall mutation rate across the 17 loci of 1.998 x 10(-3) (95% CI, 1.501 x 10(-3) to 2.606 x 10(-3)). With just one exception, all of the mutations were single-step, and they were observed only once per gametogenesis. Repeat gains were more frequent than losses, longer alleles were found to be more mutable, and the mutation rate seemed to increase with the father's age. Hum Mutat 26(6), 520-528, 2005. (c) 2005 Wiley-Liss, Inc.

RNA/DNA co-analysis from human menstrual blood and vaginal secretion stains: results of a fourth and fifth collaborative EDNAP exercise

The European DNA Profiling Group (EDNAP) organized a fourth and fifth collaborative exercise on RNA/DNA co-analysis for body fluid identification and STR profiling. The task was to identify dried menstrual blood and vaginal secretion stains using specific RNA biomarkers, and additionally test 3 housekeeping genes for their suitability as reference genes. Six menstrual blood and six vaginal secretion stains, two dilution series (1/4-1/64 pieces of a menstrual blood/vaginal swab) and, optionally, bona fide or mock casework samples of human or non-human origin were analyzed by 24 participating laboratories, using RNA extraction or RNA/DNA co-extraction methods. Two novel menstrual blood mRNA multiplexes were used: MMP triplex (MMP7, MMP10, MMP11) and MB triplex (MSX1, LEFTY2, SFRP4) in conjunction with a housekeeping gene triplex (B2M, UBC, UCE). Two novel mRNA multiplexes and a HBD1 singleplex were used for the identification of vaginal secretion: Vag triplex (MYOZ1, CYP2B7P1 and MUC4) and a Lactobacillus-specific Lacto triplex (Ljen, Lcris, Lgas). The laboratories used different chemistries and instrumentation and all were able to successfully isolate and detect mRNA in dried stains. The simultaneous extraction of RNA and DNA allowed for positive identification of the tissue/fluid source of origin by mRNA profiling as well as a simultaneous identification of the body fluid donor by STR profiling, also from old and compromised casework samples. The results of this and the previous collaborative RNA exercises support RNA profiling as a reliable body fluid identification method that can easily be combined with current STR typing technology.

Increased nuchal translucency thickness at 10-14 weeks of gestation as a predictor of severe twin-to-twin transfusion syndrome

The study examines a possible association between increased nuchal translucency thickness at 10-14 weeks of gestation in monochorionic twin pregnancies and the subsequent development of severe twin-to-twin transfusion syndrome (TTS). In 132 monochorionic twin pregnancies, including 16 that developed severe TTS at 15-22 weeks of gestation and 116 that did not develop TTS, crown-rump length, nuchal translucency thickness and fetal heart rate were measured at 10-14 weeks. In those that developed severe TTS, the prevalence of nuchal translucency thickness above the 95th centile of the normal range and the intertwin difference in nuchal translucency thickness and fetal heart rate were significantly higher than in the non-TTS group; there were no significant differences between the groups in the inter-twin difference in crown-rump length. For fetal nuchal translucency above the 95th centile, the positive and negative predictive values for the development of TTS were 38% and 91%, respectively; the likelihood ratios of nuchal translucency above or below the 95th centile for the development of severe TTS were 4.4 (1.8-9.7) and 0.7 (0.4-0.9), respectively. These findings demonstrate that the underlying hemodynamic changes associated with TTS may manifest as increased fetal nuchal translucency thickness at 10-14 weeks of gestation.

Contribution of catecholamine reactive intermediates and oxidative stress to the pathologic features of heart diseases

Pathologic heart conditions, particularly heart failure (HF) and ischemia-reperfusion (I/R) injury, are characterized by sustained elevation of plasma and interstitial catecholamine levels, as well as by the generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS). Despite the continuous and extensive research on catecholamines since the early years of the XX(th) century, the mechanisms underlying catecholamine-induced cardiotoxicity are still not fully elucidated. The role of catecholamines in HF, stress cardiomyopathy, I/R injury, ageing, stress, and pheochromocytoma will be thoroughly discussed. Furthermore and although the noxious effects resulting from catecholamine excess have traditionally been linked to adrenoceptors, in fact, several evidences indicate that oxidative stress and the oxidation of catecholamines can have important roles in catecholamine-induced cardiotoxicity. Accordingly, the reactive intermediates formed during catecholamine oxidation have been associated with cardiac toxicity, both in in vitro and in vivo studies. An insight into the influence of ROS, RNS, and catecholamine oxidation products on several heart diseases and their clinical course will be provided. In addition, the source and type of oxidant species formed in some heart pathologies will be referred. In this review a special focus will be given to the research of cardiac pathologies where catecholamines and oxidative stress are involved. An integrated vision of these matters is required and will be provided along this review, namely how the concomitant surge of catecholamines and ROS occurs and how they can be interconnected. The concomitant presence of these factors can elicit peculiar and not fully characterized responses on the heart. We will approach the existing data with new perspectives as they can help explaining several controversial results regarding cardiovascular diseases and the redox ability of catecholamines.

Ultrasound methodology used to construct the fetal growth standards in the INTERGROWTH-21st Project

A unified protocol is essential to ensure that fetal ultrasound measurements taken in multicentre research studies are accurate and reproducible. This paper describes the methodology used to take two-dimensional, ultrasound measurements in the longitudinal, fetal growth component of the INTERGROWTH-21(st) Project. These standardised methods should minimise the systematic errors associated with pooling data from different study sites. They represent a model for carrying out similar research studies in the future.

A minimal lentivirus Tat

Transcriptional regulatory mechanisms found in lentiviruses employ RNA enhancer elements called trans-activation responsive (TAR) elements. These nascent RNA stem-loops are cis-acting targets of virally encoded Tat effectors. Interactions between Tat and TAR increase the processivity of transcription complexes and lead to efficient copying of viral genomes. To study essential elements of this trans activation, peptide motifs from Tats of two distantly related lentiviruses, equine infectious anemia virus (EIAV) and human immunodeficiency virus type 1 (HIV-1), were fused to the coat protein of bacteriophage R17 and tested on the long terminal repeat of EIAV, where TAR was replaced by the R17 operator, the target of the coat protein. This independent RNA-tethering mechanism mapped activation domains of Tats from HIV-1 and EIAV to 47 and 15 amino acids and RNA-binding domains to 10 and 26 amino acids, respectively. Thus, a minimal lentivirus Tat consists of 25 amino acids, of which 15 modify viral transcription and 10 bind to the target RNA stem-loop.

Clinical improvement in patients with orthostatic intolerance after treatment with bisoprolol and fludrocortisone

Orthostatic intolerance is the development of disabling symptoms upon assuming an upright posture that are relieved partially by resuming the supine position. Postural tachycardia syndrome (POTS) is an orthostatic intolerance syndrome characterized by palpitations because of excessive orthostatic sinus tachycardia, lightheadedness, tremor, and near-syncope. Patients usually undergo extensive medical, cardiac, endocrine, neurologic, and psychiatric evaluation, which usually fails to identify a specific abnormality. The authors investigated the autonomic and hemodynamic profile of patients with POTS and the effectiveness of bisoprolol and fludrocortisone. The authors evaluated 11 female patients with POTS before and after medical treatment with a cardioselective bisoprolol beta-blocker or fludrocortisone, or both, and 11 age-matched control patients. Variability of heart rate and systolic blood pressure was assessed by fast Fourier transform, and spontaneous baroreceptor gain was assessed by use of the temporal sequences slope and alpha index. Modelflow was used to quantify hemodynamics. Symptoms in all patients improved greatly after medication. The autonomic and hemodynamic impairment observed in patients with POTS, particularly after orthostatic stress, is treated effectively with bisoprolol or fludrocortisone or both. These results need further confirmation in a controlled double-blind study. Proper medical treatment improves dramatically the clinical and autonomic-hemodynamic disturbances observed in patients with POTS. The data support the hypothesis that POTS is the result of a hyperadrenergic activation or hypovolemia during orthostasis.

Post-abortion complications after interruption of pregnancy with misoprostol

The high incidence of abortion in Brazil and the increased use of misoprostol among women having clandestine/unsafe abortions has led to an interest in evaluating whether there is an association between the use of misoprostol and the incidence of septic complications post-abortion. To test this association, a retrospective cohort study was conducted with 1840 women treated post-abortion at the Instituto Materno-Infantil de Pernambuco (IMIP) between 1988 and 1992. Incidence of infection (4.2%) was lower in women stating they had used misoprostol than in those stating that the abortion was not induced (7.9%) and twelve times lower than in women stating that they had used other methods (49.4%). These results suggest that misoprostol is a safe, inexpensive method for inducing abortion, and leads to fewer complications and consequently shorter hospital stays. Misoprostol should be considered a viable option in situations where induction of abortion is legal or medically indicated.

Contribution of oxidative metabolism to cocaine-induced liver and kidney damage

Cocaine is a potent psychoactive illicit substance and its abuse represents a major health burden worldwide. The pharmacodynamics and toxicity of cocaine have been extensively documented, and are generally associated to its affinity towards neurotransmitters transporters and several receptors. However, drug-related formation of reactive compounds, as is the case of pro-oxidant reactive species, and interaction at molecular level is still an understudied matter. The involvement of oxidative stress (OS) in cocaine-induced toxicity has been reported in both human and animal models, in several organs and systems, including heart, liver, kidney, and central nervous system (CNS). Cytochrome P450 (CYP450)-mediated cocaine metabolism yields the reactive pro-oxidant compound norcocaine (NCOC) and further oxidative metabolites. Special emphasis should be given to the stable radical norcocaine nitroxide (NCOC-NO·), which plays a key role in cocaine-induced hepatotoxicity, either by entering a futile redox cycle with an N-oxidative metabolite, or by being further oxidized to a highly reactive ion. In fact, cocaine-induced generation of reactive oxygen species (ROS) and consequent OS has been postulated based on the reactivity of cocaine N-oxidative metabolites. Depletion of cellular antioxidant defenses and impairment of mitochondrial respiration have also been considered important causes of ROS production, and subsequent cell death mediated by cocaine. The present review provides a thorough description of the current knowledge on cocaine oxidative metabolism and its role on drug-induced liver and kidney damage.

Simultaneous determination of amphetamine derivatives in human urine after SPE extraction and HPLC-UV analysis

Amphetamine derivatives are a class of compounds increasingly abused as recreational drugs in various regions of the world. Although d-amphetamine (AMPH) and 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) are among the most commonly used, the abuse of other designer drugs such as 4-bromo-2,5-dimethoxyphenethylamine (2C-B) and 4-methylthioamphetamine (4-MTA) and their involvement in acute intoxications has been increasingly reported. There is evidence that abusers ingest these compounds either alone or in combination and the respective monitoring is important for both legal and health care purposes in hospital emergency. In the present study a simple and clean solid-phase extraction procedure from urine of AMPH and MDMA, and their major metabolites p-hydroxyamphetamine (OH-AMPH) and methylenedioxyamphetamine (MDA) and 2C-B and 4-MTA was developed. Analysis was performed by HPLC-UV and the precision of the technique was between 2.9 and 5.3% for all compounds. For the overall procedure, the precision values were between 3.3 and 5.9%. Recoveries obtained from spiked urines at three concentration levels were better than 84 +/- 4% for the six compounds. The limit of detection of the method for the compounds (between 5.3 and 84.0 ng) enables their identification in urine after ingestion of fatal and non-fatal doses. The main advantages of the present method lie in its simple, clean and reliable SPE extraction method of the six amphetamine derivatives from urine followed by their simultaneous detection and quantification by liquid chromatography with UV detection.

Phrenic nerve conduction in amyotrophic lateral sclerosis

Respiratory failure accounts for the majority of deaths in amyotrophic lateral sclerosis (ALS). The main cause of respiratory failure is probably diaphragmatic weakness. In order to test the correlation between respiratory impairment and diaphragmatic function we studied the phrenic nerve conduction in 31 ALS patients. Our results showed that patients with respiratory symptoms, and decreased forced vital capacity with arterial PaO2/PaCO2 abnormalities, had more commonly increased phrenic nerve latencies or absent response due to severe diaphragm denervation than ALS patients without respiratory complaints. Diaphragmatic paresis commonly occurs during the course of ALS, and its presence and severity can be assessed by phrenic nerve studies. It is important to recognize the development of impairment in diaphragmatic function in order to prevent life-threatening complications.

Mutational analysis of the equine infectious anemia virus Tat-responsive element

A hairpinlike structure is predicted to exist at the 5' end of equine infectious anemia virus (EIAV) RNA which is similar in many ways to the human immunodeficiency type 1 (HIV-1) Tat-responsive element (TAR). In EIAV, this structure has a shorter stem than in HIV-1 and lacks the uridine bulge. Primer extension analysis of EIAV RNA was used to identify the transcriptional start site in the viral long terminal repeat. Premature termination of primer elongation at the predicted double-stranded RNA region was frequently observed and suggests that the inferred hairpin structure exists under these conditions. We have functionally characterized EIAV TAR by site-directed mutagenesis and transient gene expression analysis. It is demonstrated here that the secondary structure of this element is essential for Tat action. Mutations that disrupted base pairing abolished TAR function, and compensatory mutations that restored the stem structure resulted in Tat activation. The TAR loop appears to be closed by two U.G base pairs that are likely to provide a unique structural motif recognized by the Tat protein. With one exception, substitutions of nucleotides within the EIAV loop sequence decreased TAR function. All nucleotide substitutions of the cytidine at position +14 increased EIAV Tat responsiveness; however, its deletion abolished trans activation. Our results lead us to propose that the EIAV and HIV-1 Tat systems employ closely related cis- and trans-acting components that probably act by the same mechanism.

Quality control of ultrasound for fetal biometry: results from the INTERGROWTH-21st Project

OBJECTIVE

To assess a comprehensive package of ultrasound quality control in the Fetal Growth Longitudinal Study of the INTERGROWTH-21^st Project, a large multicenter study of fetal growth.

METHODS

Quality control (QC) measures were performed for 20 313 ultrasound scan images obtained prospectively from 4321 fetuses at 14-41 weeks' gestation in eight geographical locations. At the time of each ultrasound examination, three fetal biometric variables (head circumference (HC), abdominal circumference (AC) and femur length (FL)) were measured in triplicate on separately generated images. All measurements were taken in a blinded fashion. QC had two elements: (1) qualitative QC: visual assessment by sonographers at each study site of their images based on specific criteria, with 10% of images being re-assessed at the Oxford-based Ultrasound Quality Unit (compared using an adjusted kappa statistic); and (2) quantitative QC: assessment of measurement data by comparing the first, second and third measurements (intraobserver variability), remeasurement of caliper replacement in 10% (interobserver variability), both by Bland-Altman plots and plotting frequency histograms of the SD of triplicate measurements and assessing how many were above or below 2 SD of the expected distribution. The system allowed the sonographers' performances to be monitored regularly.

RESULTS

A high level of agreement between self- and external scoring was demonstrated for all measurements (κ = 0.99 (95% CI, 0.98-0.99) for HC, 0.98 (95% CI, 0.97-0.99) for AC and 0.96 (95% CI, 0.95-0.98) for FL). Intraobserver 95% limits of agreement (LoA) of ultrasound measures for HC, AC and FL were ± 3.3%, ± 5.6% and ± 6.2%, respectively; the corresponding values for interobserver LoA were ± 4.4%, ± 6.0% and ± 5.6%. The SD distribution of triplicate measurements for all biometric variables showed excessive variability for three of 31 sonographers, allowing prompt identification and retraining.

CONCLUSIONS

Qualitative and quantitative QC monitoring was feasible and highly reproducible in a large multicenter research study, which facilitated the production of high-quality ultrasound images. We recommend that the QC system we developed is implemented in future research studies and clinical practice. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Cervicovaginal fibronectin and cervical length at 23 weeks of gestation: relative risk of early preterm delivery

OBJECTIVES

To establish the prevalence of cervicovaginal fetal fibronectin positivity at 23 weeks of gestation in a routine population of singleton pregnancies and determine the relative risk of spontaneous delivery before 33 weeks in women with a fibronectin positive result.

DESIGN

Prospective clinical study.

SETTING

Inner city antenatal clinic.

POPULATION

Singleton pregnancies attending for routine antenatal care.

METHODS

Cervicovaginal fetal fibronectin and cervical length were measured at 23 weeks of gestation. The distribution of fibronectin positivity within subgroups according to maternal characteristics was calculated and the relative risk of spontaneous delivery before 33 weeks was estimated.

MAIN OUTCOME MEASURES

Prevalence of a fibronectin positive result and its relation to cervical length measurement and spontaneous preterm delivery before 33 weeks.

RESULTS

Of 5,146 women participating in the study, 182 (3.5%) had a fibronectin positive result and 76 (1.5%) had a cervical length of < 15 mm. Fibronectin positive women were more likely to be Afro-Caribbean in origin, to have had a previous second trimester miscarriage and to have a short cervix. In the 5,068 women who were managed expectantly, the significantly independent relative risk of spontaneous delivery at < 33 weeks was 46.2 (95% CI 18.8-113.6), for cervical length of < or = 15 mm, 8.1 (95% CI 3.8-17.5) for a fibronectin positive result, and 4.4 (95% CI 2.2-9.1) for cigarette smoking.

CONCLUSION

Fibronectin positivity at 23 weeks of gestation provides useful prediction of pregnancies at risk of spontaneous preterm delivery before 33 weeks, with a relative risk that is twice as high as cigarette smoking, but is a sixth of that of cervical length.

Amlodipine bioequivalence study: quantification by liquid chromatography coupled to tandem mass spectrometry

OBJECTIVE

To assess the bioequivalence of two amlodipine tablet formulations (Amlodipine 5 mg tablet from Merck S.A. Indústrias Químicas, Brazil as test formulation and Norvasc 5 mg tablet from Laboratórios Pfizer Ltd., Brazil as reference formulation) in 24 healthy volunteers of both sexes.

METHODS

The study was conducted using an open, randomized two-period crossover design with a 4-week washout interval. Plasma samples were obtained over a 144 h period. Plasma amlodipine concentrations were analyzed by combined liquid chromatography coupled to tandem mass spectrometry (LC-MS-MS) with positive ion electrospray ionization using multiple reaction monitoring (MRM). From the amlodipine plasma concentration vs time curves, the following pharmacokinetic parameters were obtained: AUC(last), AUC(0-inf) and C(max). The statistical interval proposed was 80-125% according to the US Food and Drug Administration Agency.

RESULTS

The limit of quantification was 0.1 ng/ml for plasma amlodipine analysis. The geometric mean and the 90% confidence interval (CI) test/reference ratios were 101.2 (92.9-110.2%) for AUC(last), 99.6 (91.5-108.4%) for AUC(0-inf) and 98.5 (89.0-109.1%) for C(max).

CONCLUSION

Since the 90% CI for AUC(last), AUC(0-inf) and C(max) ratios were within in the 80-125% interval proposed by the US FDA, it was concluded that Amlodipine 5 mg tablet (test formulation) was bioequivalent to Norvasc 5 mg tablet, in terms of both rate and extent of absorption.

Is hyperthermia the triggering factor for hepatotoxicity induced by 3,4-methylenedioxymethamphetamine (ecstasy)? An in vitro study using freshly isolated mouse hepatocytes

The consumption of 3,4-methylenedioxymethamphetamine (ecstasy; MDMA) may cause hepatocellular damage in humans, a toxic effect that has been increasing in frequency in the last few years, although the underlying mechanisms are still unknown. The metabolism of MDMA involves the production of reactive metabolites which form adducts with intracellular nucleophilic sites, as is the case with glutathione (GSH). Also, MDMA administration elicits hyperthermia, a potentially deleterious condition that may aggravate its direct toxic effects. Thus, the objective of this study was to evaluate the extent of MDMA-induced depletion of GSH, induction of lipid peroxidation and loss of cell viability in freshly isolated mouse hepatocytes under normothermic conditions (37 degrees C) and to compare the results with the effects obtained under hyperthermic conditions (41 degrees C). By itself, hyperthermia was an important cause of cell toxicity. A rise in incubation temperature from 37 degrees C to 41 degrees C caused oxidative stress in freshly isolated mouse hepatocytes, reflected as a time-dependent induction of lipid peroxidation and consequent loss of cell viability (up to 40-45%), although the variations in GSH and GSSG levels were similar to those under normothermic conditions. MDMA (100, 200, 400, 800 and 1600 microM) induced a concentration- and time-dependent GSH depletion at 37 degrees C but had a negligible effect on lipid peroxidation and cell viability at this temperature. It is particularly noteworthy that hyperthermia (41 degrees C) potentiated MDMA-induced depletion of GSH, production of lipid peroxidation and loss of cell viability (up to 90-100%). It is therefore concluded that hyperthermia potentiates MDMA-induced toxicity in freshly isolated mouse hepatocytes.

Nebulin expression in patients with nemaline myopathy

Nemaline myopathy is a structural congenital myopathy which may show both autosomal dominant and autosomal recessive inheritance patterns. Mutations in three different genes have been identified as the cause of nemaline myopathy: the gene for slow alpha-tropomyosin 3 (TPM3) at 1q22-23, the nebulin gene (NEB) at 2q21.1-q22, and the actin gene (ACTA1) at 1q42. The typical autosomal recessive form appears to be the most common one and is caused by mutations in the nebulin gene. We have studied the pattern of nebulin labeling, in patients with the typical congenital form (ten patients), the severe congenital form (two patients) or the mild, childhood-onset form (one patient), using antibodies against three different domains of nebulin. A qualitative and quantitative nebulin analysis in muscle tissue showed the presence of nebulin in myofibers from all patients. Some differences relating to the rod structure were observed. The majority of the largest subsarcolemmal rods were not labeled with the N2 nebulin antibody (I-band epitope) and showed an indistinct pattern with the two antibodies directed to the Z-band portion of nebulin (epitopes M176-181 and serine-rich domain). Diffuse rods were not revealed using the three antibodies. A discordant pattern of nebulin N2 epitope labeling was found in two affected sisters with a mutation in the nebulin gene, suggesting that modifications in nebulin distribution inside the rods might occur with the progression of the disease. Western blot analysis showed no direct correlation with immunofluorescence data. In nine patients, the band had a molecular weight comparable to the normal control, while in one patient, it was detected with a higher molecular weight. Our results suggest that presence/absence of specific nebulin Z-band epitopes in rod structures is variable and could depend on the degree of rod organization.

Involvement of the external anal sphincter in amyotrophic lateral sclerosis

In amyotrophic lateral sclerosis the striated pelvic floor sphincter muscles are functionally uninvolved, and pathological studies have confirmed the relative resistance of the Onuf nucleus motor neurons. We have evaluated the external anal sphincter (EAS) muscle in 16 patients with ALS using single fiber EMG, and compared the results with the findings in the semimembranosus-semitendinosus (SM-ST) muscles that have innervation from the L-5, S-1, and S-2 segments. The results were compared with a group of controls matched for age and sex. None of the patients or controls had symptomatic sphincter involvement and none of the 4 women studied were parous. Eight patients with ALS showed an increased fiber density in the EAS; 6 had an abnormal neuromuscular jitter. In 1 there was fibrillation in the EAS. In the SM-ST muscle 11 patients showed an increased fiber density, and 7 had an abnormal neuromuscular jitter. In 3 patients with ALS in whom there were abnormal findings in the EAS the bulbocavernosus reflex and pudendal nerve evoked potentials were normal. Neurogenic change was more marked in the SM-ST than in the EAS muscle. These findings show that the EAS is not normal in ALS. However, the relative resistance of the EAS to ALS is sufficient to prevent incontinence, even in the longer-surviving older patients.