Modeling road traffic safety based on point patterns of wildlife-vehicle collisions

Wildlife-vehicle collisions represent one of the main coexistence problems that appear between human populations and the environment. In general terms, this affects road safety, wildlife management, and the building of road infrastructures. These accidents are a great danger to the life and safety of car drivers, cause property damage to vehicles, and affect wildlife populations. In this work, we develop a new approach based on algorithms used to obtain minimum paths between vertices in weighted networks to get the optimal (safest) route between two points (departure and destination points) in a road structure based on wildlife-vehicle collision point patterns together with other road variables such as traffic volume (traffic flow information), road speed limits, and vegetation density around roads. For this purpose, we have adapted the road structure into a mathematical linear network as described in the field of Graph Theory and added weights to each linear segment based on the intensity of accidents. Then, the resulting network structure allows us to consider some graph theory methodologies to manipulate and apply different calculations to analyze the network. This new approach has been illustrated with a real data set involving the locations of 491 wildlife-vehicle collisions in a square region (40 km × 40 km) around the city of Lleida, during the period 2010-2014, in the region of Catalonia, North-East of Spain. Our results show the usefulness of our new approach to model road traffic safety based on point patterns of wildlife-vehicle collisions. As such, optimal path selection on linear networks based on wildlife-vehicle collisions can be considered to find the safest path between two pairs of points, avoiding more dangerous routes and even routes containing hotspots of accidents.

Improving fire season definition by optimized temporal modelling of daily human-caused ignitions

Wildfire suppression management is usually based on fast control of all ignitions, especially in highly populated countries with pervasive values-at-risk. To minimize values-at-risk loss by improving response time of suppression resources it is necessary to anticipate ignitions, which are mainly caused by people. Previous studies have found that human-ignition patterns change spatially and temporally depending on socio-economic activities, hence, the deployment of suppression resources along the year should consider these patterns. However, full suppression capacity is operational only within legally established fire seasons, driven by past events and budgets, which limits response capacity and increases damages out of them. The aim of this study was to assess the temporal definition of fire seasons from the perspective of human-ignition patterns for the case study of Spain, where people cause over 95% of fires. Humans engage in activities that use fire as a tool in certain periods within a year, and in locations linked to specific spatial factors. Geographic variables (population, infrastructures, physiography and land uses) were used as explanatory variables for human-ignition patterns. The changing influence of these geographic variables on occurrence along the year was analysed with day-by-day logistic regression models. Daily models were built for all the municipal units in the two climatic regions in Spain (Atlantic and Mediterranean Spain) from 2002 to 2014, and similar models were grouped within continuous periods, designated as ignition-based seasons. We found three ignition-based seasons in the Mediterranean region and five in the Atlantic zones, not coincidental with calendar seasons, but with a high degree of agreement with current legally designated operational fire seasons. Our results suggest that an additional late-winter-early-spring fire season in the Mediterranean area and the extension of this same season in the Atlantic zone should be re-considered for operational purposes in the future.

Endoscopic, bioptic, and manometric findings in eosinophilic esophagitis before and after steroid therapy: a case series

BACKGROUND AND AIM

Eosinophilic esophagitis can be associated with a wide range of endoscopic patterns. The aim of the present case series report is to describe and classify endoscopic appearances before and after corticoid therapy in relation to histopathology and manometry.

PATIENTS AND METHODS

In 30 patients (m : f, 27 : 3; mean age 36.2 years) with eosinophilic esophagitis, endoscopic findings were prospectively classified according to luminal diameter and mucosal pattern. Manometric and bioptic histopathologic findings were also recorded. Endoscopy was repeated following a 3-month course of steroid therapy.

RESULTS

In total, 20 % of patients showed a concentric esophageal stricture, and in 57 % simultaneous contraction rings were visible. Mucosal alterations consisted of granular mucosa (20 %), longitudinal furrows (33 %) and transversal undulations (3 %). Lower esophageal sphincter dysfunction and distal esophageal dysfunctional manometry were seen in 73 % and 57 % of cases, respectively. Following steroids, the esophagus showed a normal caliber in 97 % of patients, and 63 % of patients had normal mucosa.

CONCLUSIONS

The most frequent findings were narrowing of the esophageal lumen, which returned to normal following steroid treatment to a larger extent than mucosal alterations.

Budesonide combined with ursodeoxycholic acid in primary biliary cirrhosis with advanced liver damage

We describe two patients with primary biliary cirrhosis who rapidly suffered progressive liver failure and developed jaundice, despite having undergone correct therapy using ursodeoxycholic acid. Both cases showed an extraordinary clinical and biochemical response 2 months after budesonide was added to standard therapy, leading to recovery of normal liver function.

Genomic affinities between maize and Zea perennis using classical and molecular cytogenetic methods (GISH-FISH)

In this study we have analysed and compared the genomic composition, meiotic behaviour, and meiotic affinities of Zea perennis and Zea mays ssp. mays. To do so we studied the parental taxa and the interspecific hybrid Zea perennis x Zea mays ssp. mays, using classical cytogenetic methods, as well as GISH and FISH. GISH enabled us to recognize the genomic source of each chromosome involved in the meiotic configurations of this hybrid, and established the genomic affinities between their parental species. The results obtained here reinforce the hypothesis of the amphiploid origin of Zea perennis and, together with previous research, indicate that the chromosomes with divergent repetitive sequences in maize and Zea luxurians could be the remnants of a relict parental genome not shared with Zea perennis.

Simple approach to prenatal diagnosis of transposition of the great arteries

OBJECTIVE

To analyze the most relevant anomalies, seen in a sequential segmental transverse views approach to imaging the fetal heart, that provide clues to the diagnosis of complete transposition of the great arteries (TGA).

METHODS

We reviewed retrospectively all the cases of isolated TGA diagnosed in our center or submitted for a second opinion through the spatio-temporal image correlation (STIC) telemedicine (TELE-STIC) program. Only transverse cardiac sweeps were obtained. Digital video clips and STIC volumes were reviewed. The abnormal features on four-chamber, five-chamber, three-vessel (3V) and three vessels and trachea (3VT) views were analyzed.

RESULTS

The study population consisted of eight fetuses with TGA with normal extracardiac anatomy. The gestational age ranged from 13 to 32 (mean, 23) weeks. The maternal age ranged from 25 to 42 (mean, 32) years. A normal four-chamber view was seen in seven cases. Only one case demonstrated a significant ventricular septal defect. At the level of the five-chamber view a straight course arterial vessel arose from the left ventricle with lateral branches in all fetuses. In the 3V view, the ascending aorta was seen reaching more anteriorly than was the pulmonary artery in six cases. At the level of the 3VT view, two vessels (transverse aortic arch and superior vena cava) rather than three were seen in all cases.

CONCLUSION

Our proposed sequential segmental approach to imaging the fetal heart apparently allows, in five-chamber and 3VT views, clear and confident signs to be detected that aid diagnosis of TGA.

The genome organization and diversification of maize and its allied species revisited: evidences from classical and FISH-GISH cytogenetic analysis

The present review summarizes our classical and molecular cytogenetic investigations in the genus Zea. The results obtained from the meiotic behavior analysis of Zea species and hybrids, confirm the amphiploid nature of all species in the genus, with a basic number of x = 5 chromosomes. All species with 2n = 20 are diploidized allotetraploids, whereas Z. perennis (2n = 40) is an allooctoploid with four genomes somewhat divergent from one another. These analyses also revealed the existence of postzygotic reproductive isolation among Zea species. Our studies using genomic in situ hybridization (GISH) provide evidence about the evolutionary relationships among maize and its allied species, and reveal remarkable genomic divergences. Particularly, knob sequences were not completely shared between taxa previously considered to be closely related. Our data strongly suggest that the teosinte Z. mays parviglumis is not the only progenitor of cultivated maize. Introgression of Tripsacum into cultivated maize cannot be discarded.

GISHGenomic in situ hybridization reveals cryptic genetic differences between maize and its putative wild progenitor Zea mays subsp. parviglumis

The aim of this paper is to test with genomic in situ hybridization the genomic affinities between maize and its putative progenitor Zea mays subsp. parviglumis. Blocking procedures were applied for the purpose of improving discrimination among chromosome regions. Unlabeled genomic DNA from Z. mays subsp. parviglumis as a blocking agent and labeled genomic DNA from maize were hybridized on maize chromosomes. On the other hand, mitotic metaphases from Z. mays subsp. parviglumis were blocked with unlabeled genomic DNA of maize and hybridized with labeled genomic DNA from Z. mays subsp. parviglumis. Both experiments showed that either maize or Z. mays subsp. parviglumis chromosomes have their own unique sequences. This means an unexpected degree of divergence if Z. mays subsp. parviglumis is the only progenitor of maize, a result that is discussed in relation to our previous genomic in situ hybridization observations and to the different scenarios proposed about the origin of maize.

Cardiac defects in chromosomally normal fetuses with increased nuchal translucency at 10-14 weeks of gestation

OBJECTIVE

To examine the prevalence, distribution and spectrum of cardiac defects in chromosomally normal fetuses with increased nuchal translucency thickness.

PATIENTS AND METHODS

During a 4-year period, targeted fetal echocardiography was used in 353 chromosomally normal fetuses with increased nuchal translucency thickness at 10-14 weeks' gestation. The cardiac scan was performed at 18-22 weeks. In the last 138 cases enrolled, an additional scan at 12-16 weeks was carried out. The follow-up included the findings at necropsy or in the pediatric examination. A complete follow-up was achieved in 97%.

RESULTS

Cardiac defects were present in 32 (9.1%) cases, increasing from 5.3% in those with a nuchal translucency thickness of > or = 95th centile (3.9 mm) to 24% when thickness > or = 6 mm (p < 0.001). In 31 cases (97%), the cardiac defect was diagnosed antenatally; in 24 cases (77%) this diagnosis was confirmed later. In the remaining seven cases, the autopsy examination was not available. A wide range of cardiac defects was observed, with the most common being atrioventricular septal defect and tricuspid atresia.

CONCLUSIONS

Euploid fetuses with increased nuchal translucency thickness have a significantly increased risk of cardiac defects. This is a marker of different types of heart anomalies and constitutes an additional indication for targeted fetal echocardiography. Most of the cardiac defects can be detected by fetal echocardiography.

The role of ductus venosus blood flow assessment in screening for chromosomal abnormalities at 10-16 weeks of gestation

OBJECTIVE

To evaluate the role of ductus venosus blood flow assessment at 10-16 weeks' gestation in screening for chromosomal abnormalities.

METHODS

Ductus venosus blood flow was prospectively evaluated in 1371 consecutive pregnancies between 10 and 16 weeks of gestation. The pulsatility index for veins was calculated. All cases were screened for chromosomal defects combining maternal age and fetal nuchal translucency thickness.

RESULTS

A chromosomal abnormality was found in 20 cases. The overall detection rate, specificity, positive predictive value, negative predictive value and odds ratio for chromosomal abnormalities were 65%, 95.7%, 18.3%, 99.5% and 41 (95% CI 16-108), respectively, when using the 95th centile pulsatility index as a cut-off.

CONCLUSIONS

These preliminary results suggest that evaluation of the ductus venosus pulsatility index at 10-16 weeks' gestation is a useful second-line screening test for chromosomal defects. A combination of nuchal translucency measurement and ductus venosus assessment might increase specificity while maintaining an optimal detection rate for chromosomal abnormalities. Such a policy could identify 55% of all chromosomal abnormalities and about 69% of autosomal trisomies, reducing the need for invasive testing to less than 1%.

Selective versus non-selective laser photocoagulation of placental vessels in twin-to-twin transfusion syndrome

OBJECTIVE

We have recently described a surgical technique for the treatment of twin-to-twin transfusion syndrome (TTTS) that allows precise identification of vascular anastomoses (selective laser photocoagulation of communicating vessels, or S-LPCV). The purpose of this study was to compare S-LPCV with the previous non-selective technique (NS-LPCV) that targeted all vessels crossing the dividing membrane.

MATERIALS AND METHODS

Patients with TTTS were treated with NS-LPCV from May 1994 to June 1997 and with S-LPCV from July 1997 to December 1999. TTTS was defined as polyhydramnios of > or = 8 cm maximum vertical pocket (MVP) in the recipient twin and oligohydramnios of < or = 2 cm MVP in the donor twin. Outcome was measured as survival per number of pregnancies and per number of fetuses together with limited morbidity data.

RESULTS

NS-LPCV was used in 18 patients and 74 were treated with S-LPCV. Three patients interrupted their pregnancies electively after surgery (S-LPCV) and were removed from further analysis. Survival of at least one fetus was higher in S-LPCV (83.1%) than in NS-LPCV (61.1%) (P = 0.04), mostly due to a lower rate of dual intra-uterine fetal demise in S-LPCV (5.6%) than in NS-LPCV (22%) (P = 0.05). There were more hydropic fetuses in the NS-LPCV group (27%) than in the S-LPCV group (5.4%), but this difference did not account for the results. There was no difference in the survival per number of fetuses between the two groups.

CONCLUSIONS

S-LPCV represents an important evolution in the surgical treatment of TTTS. The use of this technique by all centers should allow better comparison of fetal survival and morbidity rates. S-LPCV should be the standard technique in trials comparing amniocentesis versus laser for the treatment of severe TTTS.

Genomic affinities of Zea luxurians, Z. diploperennis, and Z. perennis: Meiotic behavior of their F1 hybrids and genomic in situ hybridization (GISH)

Since 1987 cytological evidence has arisen in our laboratory, pointing to x = 5 as the original basic chromosome number of maize and its related wild species. This paper deals with the analysis of the meiotic behavior of F1 hybrids Zea luxurians × Z. diploperennis (2n = 20) and Z. luxurians × Z. perennis (2n = 30). In the first hybrid the most frequent configuration was 8ll + 4l and in the latter was 5lll + 5ll + 5l. Applying GISH (genomic in situ hybridization) to mitotic chromosomes of Z. luxurians we found that DAPI (4', 6-diamidino-2-phenylindole) positive bands located in all telomeric regions of this species did not hybridize with either Z. perennis or Z. diploperennis genomic probe. Therefore, Z. luxurians has a repetitive sequence that can be used in fluorescent staining to identify its chromosomes. When GISH was employed on metaphase I of the 2n = 30 hybrid, all the univalents showed distinctive telomeres of Z. luxurians, while the bivalents did not present any signal. These findings show that the formation of bivalent-univalent configurations is not a random event. The bivalents tend to be spatially separated and are very often observed forming an independent group of 5II. Finally, trivalents were composed by one chromosome labeled in its telomeric regions, and two smaller and unlabeled ones. The use of chromosome markers of Z. luxurians demonstrated to be a good step forward in interpreting the nature of meiotic configurations in 2n = 30 Zea spp. hybrids. They can help to clarify the relationship between genomes and provide a useful addition to the taxonomic classification in the genus Zea.Key Words: Zea hybrids, evolution, cytogenetics, repetitive sequences, heterochromatic knobs.

Genomic in situ hybridization (GISH) of Tripsacum dactyloides and Zea mays ssp. mays with B chromosomes

Genomic affinities between Tripsacum dactyloides (2n = 72) and Zea mays ssp. mays (2n = 20 + 5 B) were analyzed through GISH (genomic in situ hybridization) to ascertain the degree of chromosome homology between the two genera. Mitotic cells of T. dactyloides were simultaneously probed with total genomic DNA from Z. mays ssp .mays (2n = 20) and with rDNA (pTA71). A disperse pattern of hybridization signal among all 72 chromosomes, corresponding to maize total DNA, and six strong fluorescent signals due to the rDNA probe hybridizing on 3 chromosome pairs of T. dactyloides were observed. Mitotic chromosomes from Z. mays ssp. mays (2n = 20 + 5 B) were hybridized with a maize line that lacked B chromosomes and knobs and with total DNA from T. dactyloides. The knobless line of maize hybridized intensely on all chromosomes except for some regions where the probe bound less. Tripsacum dactyloides bound intensely on one terminal region of each B chromosome and to some regions of chromosome pairs 2, 6, and 8. These regions are DAPI positive and coincide with regions that displayed lower affinity with the probe from the knobless maize line. The possible significance of these results is discussed briefly.Key words: Tripsacum dactyloides, Zea mays ssp. mays, maize B chromosomes, genomic in situ hybridization, GISH.

[Gastrointestinal anisakiasis. Seven cases in three months]

Human anisakiasis or anisakidosis is an unusual parasitation. During the autumn of 1996 seven patients came to our Hospital for such a condition. Five of these patients had the parasites in the gastroduodenal area (1 in the gastric body, 3 in the antrum and 1 in the duodenal bulb, this one with two parasites). Four out of the five patients consulted us for intense epigastric pain; only one developed a cutaneous rash. The fifth patient was diagnosed unexpectedly during an endoscopy appointment. Eosinophilia was detected in none. All the parasites were extracted endoscopically and identified as belonging to the Anisakis genera. Excepting for the patient with no complaint, the other four showed adhered larvas to mucosa. The two other patients were operated because of acute abdominal pain. At laparotomy an ileitis was seen and then resected. Under microscopic examination both ileon were found to be edematous and infiltrated by eosinophils. Anisakis larvae were observed in the submucosa of one of the removed intestines. The other patient was diagnosed after an immunologic study consisting of radioimmunoassay and Western Blot. Five of the seven patients (71%) acquired the parasites after consumption of anchovies with vinegar.

Prenatal diagnosis of isolated hypospadias

Ten cases of prenatal diagnosis of isolated hypospadias are presented, six of them in the second trimester. The echographical basis for the suspected diagnosis of hypospadias are: anomalous distal morphology of the penis, small lateral folds (dermal remains of the prepuce), small penis with ventral incurving and anomalous urinary stream. The embryogenesis and the clinical utility of prenatal study of the genitals of the fetus, not only to determine the sex, but also to detect anomalies, are discussed.

Prenatal diagnosis of testicular torsion

A case of the prenatal diagnosis of testicular torsion at 39 weeks' gestation is presented. The affected testicle was observed as a small rounded area of hypoechogenicity with a peripheral echogenic ring without hydrocele. The appearance was suggestive of the chronic phase of testicular torsion. The neonatal genital exploration confirmed the diagnosis.

Early detection of reversed diastolic umbilical flow: should we offer karyotyping?

In normal pregnancy, end-diastolic flow appears in the umbilical artery around the 13th week of gestation, with a velocity which increases progressively with advancing gestation. The detection of reversed flow in the umbilical artery, the highest expression of an increase in placental vascular resistance, is extremely uncommon in the first half of gestation and, in three of the four cases reported in the literature, there were chromosomal abnormalities. We report a new case of reversed end-diastolic flow in the umbilical artery in a 13-week fetus with increased nuchal translucency thickness, megacystis and tachycardia. Cytogenetic analysis of chorionic villi and amniocytes revealed trisomy 13. The findings provide further evidence for a possible association between reversed end-diastolic flow in the umbilical artery and chromosomal abnormalities. However, the effectiveness of this potential marker in an unselected population requires further evaluation.

[Complete congenital atrioventricular block. Prenatal diagnosis and perinatal management]

OBJECTIVE

To describe our experience in prenatal diagnosis and perinatal management of congenital atrioventricular heart block, as well as pacemaker treatment in the neonate.

MATERIAL AND METHODS

A total of 13 fetuses are included. The diagnosis of atrioventricular dissociation was established by Doppler heart rate sample in the right atrium to show the atrial activity while the sample in the Aorta reflected the ventricular heart rate. Gestational age at diagnosis, ventricular heart rates, autoimmune maternal pathology, maternal blood tests for autoantibodies antiRo+, congenital structural heart disease, fetal hydrops, maternal medical treatment, perinatal results and pacemaker neonatal implantation are described.

RESULTS

Gestational age at diagnosis ranged between 22 and 32 (mean 27.6) weeks. Ventricular heart rates ranged between 32 to 80 (mean 54) beats/min. AntiRo+ antibodies were detected in 5 mothers, and clinical systemic lupus erythematosus was found in only one. Four had congenital heart disease (2 ventricular inversion and corrected TGA, 1 complete atrio-ventricular canal and 1 tricuspid atresia). Signs of heart failure and hydrops were detected in 9 fetuses. Treatment with beta-metasona and ritodrine was administered to 7 mothers when the ventricular heart rate dropped below 60 beats/min. Intrauterine fetal death occurred in 3 fetuses with structural congenital heart disease and hydrops. Delivery was performed by cesarean section in 8 preterm fetuses (one them a twins), 3 spontaneous deliveries at term and 3 stillbirth. Postnatal pacemaker implantation was carried out in 9 newborns (3 cases with unicameral temporal right ventricle electrode and 6 cases with permanent bicameral electrodes implanted through the subclavian vein and DDD pacemaker). Follow-up of the bicameral pacemaker group was satisfactory.

CONCLUSION

Persistent fetal bradycardia is the first sign to diagnose prenatal complete atrioventricular heart block. Echocardiography asses fetal haemodynamic status and may detect signs of fetal deterioration. Hydrops and further drop in the ventricular heart rate warrant urgent cesarean section and pacemaker management of the newborn.

Use of interferon-alpha in laryngeal papillomatosis: eight years of the Cuban national programme

Laryngeal papillomatosis is one of the first diseases where interferon (IFN) was found to be effective. In 1983, a programme for the treatment of all such cases started in Cuba. Up to December 1991, 125 patients (92 children, 33 adults) have been treated: 102 with leucocyte IFN-alpha, 12 with recombinant IFN-alpha-2b, and 11 have received both preparations. Case management consisted of surgical removal of the lesions followed by an IFN schedule starting with 10(5) IU/kg of weight in children or 6 x 10(6) IU in adults, i.m. daily. The dose was progressively reduced, as long as no relapses occurred. At the end of the one-year schedule the doses were reduced to 5 x 10(4) IU/kg in children or 3 x 10(6) IU in adults, weekly. If there was a relapse, it was removed surgically and the patient returned to a higher dose level. Most cases (89; 71 per cent) have not relapsed after the treatment; 60 of them have been followed for more than three years. In those with relapses, the frequency of recurrence decreased in all but four patients. The treatment seemed to be more effective if initiated less than three months after the disease onset. The tracheostomy could be removed in five out of seven patients who needed it before the IFN treatment and was necessary in only three new cases during IFN treatment. In two of these, decannulation was possible later on. In a total of 14 patients relapses persisted after several cycles of IFN treatment. They were considered resistant to such treatment. No severe side effects were reported. The most frequent ones were fever, drowsiness, increased bronchial secretion, chills and headache. The establishment of this programme has maintained the disease under control in Cuba.

Reversed end-diastolic umbilical artery velocity in two cases of trisomy 18 at 10 weeks' gestation

Doppler velocimetry of the umbilical artery was carried out during routine ultrasound examinations performed immediately before either chorionic villus sampling (n = 383) or genetic amniocentesis (n = 649) in 1032 women referred for prenatal diagnosis at our institution, between 10 and 18 weeks of gestation. Reversed end-diastolic flow was detected in only two cases (0.19%), both of which were affected by trisomy 18. The diagnosis was made at 10 weeks' gestation and, to our knowledge, these are the earliest records of this pathological Doppler pattern. Although a possible relationship with early abnormal placentation remains to be established, the finding of reversed end-diastolic velocities in the umbilical artery in the first trimester of pregnancy may be an early sign of karyotype abnormality.

First-trimester biochemical screening for Down syndrome with the use of PAPP-A, AFP, and beta-hCG

Biochemical screening for Down syndrome (DS) is well established in the second trimester of pregnancy, but there is little information available on its value in the first trimester. This study describes our preliminary results with biochemical screening for DS in the first trimester of pregnancy in order to evaluate its efficacy at this time. Our study population, including 19 DS pregnancies, was evaluated using maternal serum levels of alpha-fetoprotein (AFP), beta-human chorionic gonadotropin (beta-hCG), and pregnancy-associated plasma protein A (PAPP-A). At a false positive rate (FPR) of 5 per cent, the detection rate (DR) for DS is 9 per cent for beta-hCG, 18 per cent for AFP, and 66 per cent for PAPP-A when considering these parameters individually. With different combinations of the analytes, the best detection rates are obtained with the association of PAPP-A and AFP (85 and 82 per cent DR for a 10 and 5 per cent FPR, respectively). Our data support the value of first-trimester biochemical screening for DS and that of PAPP-A as a single marker.

Umbilical artery pulsatility index in early pregnancies with chromosome anomalies

OBJECTIVE

The aim of our study was to obtain measurements of the umbilical artery pulsatility index in pregnancies before invasive procedures for prenatal diagnosis, to investigate its potential prognostic value in predicting chromosomal abnormalities.

DESIGN

A prospective study.

PARTICIPANTS

Nine hundred and twenty-four consecutive women with singleton pregnancies between 10 and 18 weeks of gestation who underwent chorionic villus sampling (n = 385) or genetic amniocentesis (n = 539). All Doppler measurements were obtained by a single investigator before the invasive procedure. Pregnancies where structural malformations were detected by ultrasound were excluded.

RESULTS

Twenty-six fetuses with chromosomal anomaly, including 12 with trisomy 21, were diagnosed. Using the 90th centile in umbilical artery pulsatility index values as a cut-off for trisomy 21 the detection rate was 66.6%, with a specificity of 90.4% and a positive predictive value (defined as the proportion of unaffected individuals with positive results, l-specificity) of 8.8%. However, with this cut-off the false positive rate was 9.6%. All 19 chromosomally normal pregnancies in which a fetal loss occurred after the procedure had a normal umbilical artery pulsatility index before it was carried out.

CONCLUSIONS

These preliminary data suggest that trisomic fetuses have an abnormally increased umbilical artery pulsatility index in early pregnancy. Because the number of cases is too small to draw any firm conclusions, the use of a single measurement for screening purposes needs to be confirmed by further investigation and the clinical significance of reference curves of normal values in the detection of pathological conditions has still to be determined. The potential of umbilical artery pulsatility index as an additional parameter along with others previously established for Down's syndrome screening, such as nuchal oedema, needs to be explored further.

Immediate changes in umbilical blood flow after transcervical chorionic villus sampling performed by biopsy forceps

Transvaginal ultrasonography with colour Doppler was used to evaluate the immediate changes on the fetal heart rate (FHR) and the fetal umbilical artery pulsatility index (PI) after chorionic villus sampling (CVS). This prospective study included 279 consecutive singleton pregnancies, between 10 and 13 weeks, of women who underwent transcervical CVS in our institution. All Doppler measurements were obtained transvaginally before and immediately after CVS. Structural malformations detected by ultrasound were excluded. Student's t- and Wilcoxon texts were performed for statistical analysis. The results showed no significant decrease in FHR (mean 1.04 beats, t = 1.68, P = 0.94) and a significant elevation of umbilical artery PI (mean 0.12, t = - 6.51, P < 0.001) post-CVS. This difference was only significant in procedures performed at less than 11 weeks' gestation, since there was no significant change for those procedures performed thereafter. These preliminary data suggest that acute fetal haemodynamic changes are induced by CVS and may have clinical effects. Hypotheses on possible vascular mechanisms are discussed. Colour Doppler could widen the possibilities for more accurate in vivo assessment and research on CVS-related placental injury.

Doppler assessment of umbilical flow after genetic amniocentesis

The aim of our study was to evaluate the immediate changes on the fetal heart rate (FHR) and the fetal umbilical artery pulsatility index (UPI) after performing genetic amniocentesis. This was a prospective study including 431 consecutive singleton pregnancies between 14 and 18 weeks undergoing genetic amniocentesis in our institution. Doppler measurements were obtained transabdominally before and immediately after the procedure. Structural malformations detected by ultrasound were excluded. Student's t-test was performed for comparisons among different groups and observed mean changes. The results showed a significant decrease in FHR post-amniocentesis (mean 1.5 beats, t = 3.47, P < 0.01) and a non-significant elevation in UPI (mean -0.01, t = -0.29, P = 0.77) after the procedure. Differences in FHR could be found when analyzed by each gestational week. These preliminary data suggest that although acute fetal hemodynamic changes are detected after genetic amniocentesis, such changes are unlikely to have clinical relevance. However, it is reasonable to propose the use of Doppler as a method of assessing hemodynamic effects caused by prenatal invasive procedures in order to provide more accurate in vivo research on this issue.

Fetal heart rate patterns in pregnancies with chromosomal disorders or subsequent fetal loss

OBJECTIVE

To evaluate whether an abnormal fetal heart rate (FHR) is associated with chromosomal abnormalities in pregnant women undergoing an invasive procedure for prenatal diagnosis, and to investigate an abnormal FHR's potential value in predicting fetal loss in chromosomally normal pregnancies after the procedure.

METHODS

This was a prospective study including 867 women, all consecutive singleton pregnancies at 10-18 weeks' gestation, who underwent chorionic villus sampling (n = 371) or genetic amniocentesis (n = 496) at our institution. Fetal heart rate, expressed as beats per minute, was measured before the invasive procedure. Structural malformations detected by ultrasound were excluded.

RESULTS

Chromosomal abnormalities were diagnosed in 25 fetuses, including 11 with trisomy 21. In ten of 25 fetuses with chromosomal abnormalities, the FHR was between the fifth and 95th percentiles established before the procedure for the chromosomally normal group with normal outcome. Using the fifth percentile as a cutoff for trisomy 21, the detection rate was 63.6%, with a specificity of 96.2% and a positive predictive value of 17.9% (one in 5.5) in our population. Moreover, in six of the ten chromosomally normal miscarriages occurring within 4 weeks after the procedure, the FHR was above the 95th percentile.

CONCLUSION

Although the value of a single measurement for screening purposes needs to be confirmed by further investigation, our preliminary data suggest that chromosomal anomalies, especially trisomy 21, may be suspected in fetuses with an abnormally low FHR in early pregnancy. In chromosomally normal fetuses, the detection of an abnormally high FHR in some degree may be predictive of fetal loss after the invasive procedure.

Biochemical and Doppler predictors of poor perinatal outcome in a fetus with four umbilical vessels

Unexpected elevation of maternal serum alpha-fetoprotein (MSAFP) in women with anti-phospholipid syndrome has already been described as a predictor of fetal death. In this report we present a case of a pregnant woman with elevated second trimester MSAFP, in which Doppler ultrasound at 28 weeks suggested very poor fetal prognosis. A cesarean section was performed, but 2 days later the infant died due to distress. The only remarkable feature at post-mortem study was the finding of four vessels in the umbilical cord. Conventional investigation of the mother led us to the diagnosis of a primary anti-phospholipid syndrome. The finding of such an association should alert clinicians to the increased risk of fetal death. Precocious Doppler ultrasound examination may be the elective non-invasive technique to monitor such high risk fetuses.

The influence of the site of Doppler recording on umbilical artery pulsatility index during the first trimester

The aim of our study was to determine the pulsatility index (PI) of the umbilical artery velocity waveform obtained from the fetal insertion, the placental insertion and a free floating loop of the umbilical cord. This was a prospective study involving 60 consecutive singleton pregnancies undergoing ultrasound examination between 10 and 13 weeks' gestation. Doppler measurements were obtained transvaginally from the placental and the fetal abdominal insertion, and from a free floating loop of umbilical cord. Chromosomal abnormalities and structural malformations detected by ultrasound were excluded. A multi-way analysis of variance did not show significant differences between the measurements of umbilical PI at the different sites of the umbilical cord and Pearson's coefficient showed an excellent correlation between them. No significant intra- and interobserver differences were found. In conclusion, measurements of Doppler velocimetric indices of the umbilical artery during the first trimester are not influenced by the recording site and these recordings are reproducible at this stage of gestation.

First-trimester nuchal edema as a marker of aneuploidy

Targeted ultrasonographic screening for nuchal fluid accumulation during the first trimester (9-13 weeks) seems to be a recommendable method for the detection of Down's syndrome and other chromosomal anomalies in pregnant women. It compares favorably with current methods of maternal serum screening performed during the second trimester. Using a 4-mm cut-off value, the detection rate of aneuploidy among our population was found to be 57.1%, with a false-positive rate of 0.7% and a positive predictive value of 72.7%. Chromosomal analysis should be considered for fetuses with nuchal translucency equal to or greater than 4 mm in the first trimester.

The prevalence of cocaine abuse during pregnancy in Barcelona

The aim of our study was to determine the prevalence of cocaine abuse, by means of positive urine toxicology screens or targeted questionnaire, among women in labor at our hospital. The prospective study included 1773 women who delivered consecutively in our institution. All of them underwent a standardized questionnaire including drug use and demographic data. Urine samples were obtained during labor. Urine toxicology screens for cocaine and its metabolites, opiates, and ethanol were performed by enzyme multiplied immunoassay technique. Information was coded in order to maintain anonymity. Among the 1773 women in labor we screened, the mean age was 27.8 years and the overall prevalence of a positive questionnaire for cocaine was 0.3% and a positive urine toxicology was 0.8%. Results by drug and by demographic items are analysed. There was a substantial denial of cocaine use among the toxicologically positive patients, since only 43% of them referred its use at any time during pregnancy, in conclusion, the use of illicit drugs is common among pregnant women in our institution, but cocaine does not seem to be as prevalent as it is in the USA, while in the labor room most women with a positive test do not refer the use of the drug. Urine toxicology screening increases the rate of detection of substance abuse in this population of women. These studies are necessary to target educational programs among pregnant women.

Body stalk anomaly associated with maternal cocaine abuse

A case of body stalk anomaly diagnosed prenatally by ultrasound during the 24th week of pregnancy in a cocaine abusing mother is presented. Accurate visualization of the fetal organs was difficult due to the severe oligohydramnios caused by premature rupture of membranes, probably related to the cocaine use. The sonographic findings were an omphalocoele, fetal attachment to the placenta, kyphoscoliosis, and absence of a floating umbilical cord. The prenatal diagnosis of the syndrome and the possible relationship with cocaine abuse are discussed.

Maternal primary pulmonary hypertension associated with pregnancy

Primary pulmonary hypertension (PPH) is a very uncommon clinical entity, with a high mortality when associated with pregnancy. Three cases of PPH associated with gestation and different outcomes are reported, and a literature review concerning its management and outcome is made. We emphasize the importance of a strict control of such patients, with the supportive cardiovascular measures and surveillance of fetal well-being. The peculiar handling of the course of delivery and the type of anaesthesia is discussed.

Bilateral renal agenesis and cytomegalovirus infection in a case of Fraser syndrome

A case of Fraser syndrome diagnosed prenatally is presented. Detection of oligohydramnios, hydrops fetalis and bilateral absence of the kidneys were the initial findings leading to further study. Specific IgM for cytomegalovirus in maternal serum and confirmed infection by fetal blood sampling was an associated finding. The importance of an etiologic diagnosis of nonimmune hydrops and the relevant aspects of genetic counselling are emphasized. The association of the Fraser syndrome with cytomegalovirus infection has not been previously reported.

[Cardiac arrest in newborn of mother treated with labetalol]

The use of beta-adrenergic antagonists for the control of high blood pressure associated to pregnancy is frequent. Their use is related with the appearance of undesirable effects of the fetus. The case of neonatal cardiac arrest attributed, to the administration of labetalol to the mother is presented. The high transplacentary passage, the different pharmacokinetics of the drug in the newborn and the clinical evolution of the patient suggests its involvement. It is concluded that labetalol may cause severe undesirable effects in newborns and fetal heart rate of the mother and neonate should be monitored upon use of this drug.