Comparison of CRUSADE and ORBIT bleeding risk scores in prediction of mayor bleeding in pacients with acute coronary syndrome

Introduction

Mayor bleeding is the most important complication of antithrombotic treatment in acute coronary syndrome (ACS) and is even associated with higher mortality. The CRUSADE scrore has been developed to predict mayor bleeding in ACS and is one of the most used. however, it has a moderate predictive capacity and is relatively complex to calculate at the patient's bedside. On the other hand, different bleeding risk scores have been developed for atrial fibrillation witch have also been evaluated for ACS, for example HAS-BLED. Recently, the NICE guidelines suggest using the Orbit Bleeding score (ORBIT) to assess the risk of bleeding in atrial fibrillation due to its greater predictive capacity. Its usefulness in the context of ACS has been little studied.

Purpose

The aim of the study is to evaluate the usefulness of the ORBIT to predict major bleeding in patients with ACS compared to the CRUSADE

Methods

A obserbational retrsopective study was performed. Patients with diagnostico ACS in two coronary units of Argentina were included. All of them, received antocoagulation as a antithrombitic treatment. The CRUSADE and ORBIT scores were calculated with the clinical data on admission. The primary point of major bleeding, defined as a BARC classification 3 or 5, was analyzed. Multivariate analysis was performed by logistic regression. To establish the discrimination capacity of the scores, the area under the ROC curve (AUC) was evaluated and the comparison between the curves was carried out using the chi-square area homogeneity test.

Results

A total of 880 patients were included (68% with non-ST elevation ACS and 32% with ST elevation), the mean of age was 68±11 years and 35% were women. As antithrombotic treatment, 100% received aspirin, 96.3% received P2Y12 receptor inhibitors, 100% received anticoagulation with enoxaparin, and 9.5% received fibrinolytics.

The primary end point of major bleeding occurred in 3.4% (n=30).

In univariate analysis both CRUSADE and ORBIT were predictors of mayor bleeding, but in multivariate analysis only ORBIT was independent predictor of mayor bleeding. (ORBIT OR: 2.46 (95% CI 1,61 to 3,97), P<0.001. The table shows the univariate and multivariate analysis.

The AUC of CRUSADE was 0.68 (95% CI 0.57–0.80) and the ORBIT was 0.80 (95% CI 0.72–0.90). The ORBIT score presented a higher AUC than the CRUSADE (p=0.03). See Figure 1.

Conclusion

The Orbit score was an independent predictor of major bleeding in patients with ACS, presenting a better predictive capacity than the CRUSADE.

Funding Acknowledgement

Type of funding sources: None.

Higth-sensitivity T troponin and NT pro B-type natriuretic peptide as predictors of early development of structural heart disease in patients with stage 0 of Chagas disease

Background

Approximately 30% of patients with Chagas disease (ChD) develop structural heart disease at some point in their evolution. There is an asymptomatic period where there is no evidence of cardiac involvement, called stage 0. Prognostic evaluation in this group of patients remains a challenge. On the other hand, the presence of elevated hight-sensitivity T troponin (HS-TnT) and N-terminal pro B-type natriuretic peptide (NT-proBNP) has been documented in the early stages of the ChD. The role of these biomarkers as predictors of early development of structural heart disease in the follow-up of stage 0 ChD has been poorly studied.

Purpose

The aim of this study is to evaluate if HS-TnT and NT-proBNP are a predictor of early development of cardiac structural alterations in the follow up of patients with stage 0 ChD.

Materials and methods

Outpatients with stage 0 of ChD (positive serology, with normal electrocardiogram, 24-hours holter and echocardiogram) were included prospectively. Baseline measurement of HS-TnT and NT-proBNP was performed. The follow-up was carried out with serial echocardiography and 24-hour Holter. The end point of development of structural heart disease was considered, defined as one of the following: left ventricular dilation (diastolic diameter of left ventricle >60 mm in men or >55 mm in women), deterioration of ventricular function (Drop >10 points of Left Ventricular Ejection Fraction (LVEF) or LVEF <50%), Complex ventricular arrhythmia or Atrio-ventricular block ≥ second degree Mobitz II. Univariate and multivariate analysis was performed by cox regression.

Results

Three hundred two patients were included, with 47±9 years old, 46% woman. With a median of follow-up of 34 (interquartile range 19 – 43) months, the end point of development of structural heart disease was presented in 4.6% (n=14 patients). In multivariate analysis both HS-TnT and NT-ProBNP were independent predictors of development of structural heart disease [HR 1.18 (IC95% 1.05–1.33), p=0.003 and HR 1.01 (CI95% 1.00–1.01), p=0.001; respectively]. The area under the Receiver operating characteristic (ROC) curve was calculated, for HS-TnT it was 0.80 (95% CI 0.65–0.93), with a cut-off point for HS-TnT >14 ng/ml and for NT-proBNP it was 0.88 (95% CI 0.83–0.95) with a cut-off point for NT-proBNP >200 pg/ml. The figure shows the Kaplan-Meier curve for HS-TnT and NT-proBNP. In adjusted analysis, HS-TnT >14 ng/ml had a HR 5.27 (CI95% 1.4–18.9), p=0.01 and NT-proBNP HR 3.07 (CI95% 1.01–10.9), P=0.04.

Conclusions

In our population of patients with stage 0 chagas disease, HS-TnT and NT-proBNP were independent predictors of early development of structural heart disease, with good predictive capacity. The baseline measurement of these biomarkers can be useful in the evaluation and follow-up of patients with ChD without initial evidence of cardiac involvement.

Funding Acknowledgement

Type of funding sources: None. Kaplan-Meier curve

The addition of flexible endoscopic suturing to stenting for the management of transmural esophageal wall defects: a single tertiary center experience

BACKGROUND AND AIMS

Endoscopic stenting is the standard of care for full thickness esophageal wall defects. The aim of this study is to evaluate outcomes of endoscopic closure of esophageal defects using stenting, with or without endoscopic suturing.

METHODS

This is a single-center retrospective study of patients with esophageal wall defects who underwent endoscopic interventions. Outcomes of stenting with or without endoscopic suturing of the defect were assessed. Univariate and multivariate logistic regression models were used to examine factors associated with successful defect closure.

RESULTS

One hundred and fourteen patients with esophageal wall defects underwent 254 endoscopies with an overall complete closure rate of 75.8%. Twenty-three (20.2%) patients underwent primary closure using endoscopic suturing and subsequent esophageal stenting, while 91 (79.8%) underwent esophageal stenting only. The dual modality group (versus the stent-only group) had similar defect closure rates (84.2 vs. 73.8%, p = 0.55) and time to stent migration (37 vs. 12.5 days, p = 0.07), but was associated with longer procedure times (60 vs. 36 min, p < 0.01) and fewer additional endoscopic procedures (13.6 vs. 43.2%, p = 0.01). Stent suturing significantly decreased migration (35.5 vs. 58.5%, p = 0.04), was associated with fewer additional endoscopies (15.4 vs. 50%, p < 0.01) and reduced need for additional stents (7.7 vs. 34.3%, p < 0.01). On multivariate analysis, chronic defects (> four weeks old) were 81% less likely to close compared to acute (≤ 4 weeks) defects (OR 0.19, CI 0.04-0.77, p = 0.02), and large diameter stents (23 mm) were associated with higher odds of defect closure (OR 3.36, CI 1.02-11.4, p = 0.04).

CONCLUSION

Endoscopic treatment of esophageal wall defects is safe, effective, and more likely to be successful in acute defects using larger caliber stents. Stent suturing reduces migration, need for additional endoscopic procedures, and stent exchanges. Further comparative studies with larger cohorts are needed to validate our results.

Association between the elevation of biomarkers and incipient alterations in ventricular function in patients with Chagas disease without evidence of specific organ damage

Background

Chagas disease (ChD) has a long asymptomatic period, where there is no evidence of myocardial damage. However, incipient alterations in ventricular systo-diastolic function have been described using echocardiography with Tissue Doppler and Strain. On the other hand, the presence of elevated higth-sensitivity T troponin (HS-TnT) and N-terminal pro B-type natriuretic peptide (NT-pro BNP) has been documented in the early stages of the ChD. The association between the elevation of both markers and incipient alterations in ventricular function in patients with ChD without evidence of heart damage has been poorly studied.

Purpose

The aim of this study is to evaluate the prevalence of elevation of both biomarkers (HS-TnT and NT-proBNP) and their association with insipients alterations in systo-diastolic function in patients with ChD without evidence of structural heart affection.

Materials and methods

Outpatients with stage 0 of ChD (positive serology, with normal electrocardiogram, holter and chest teleradiography) were included prospectively. They were divided in three groups according to the dosage of HS-TnT and NT-proBNP. Group 1: patients with both markers within normal values; group 2: patients with elevation of one of the markers (HS-TnT&gt;13 ng/L OR NT-proBNP&gt;125 pg/ml) and group 3: patients with elevation of both markers (HS-TnT&gt;13 ng/L AND NT-proBNP&gt;125 pg/ml). All of them underwent Doppler echocardiography with tissue Doppler.

Results

Two hundred and sixty-one patients were included, with 47±9 years old of age, 44% woman, 86.6% (n=226) in group 1, 9.6% (n=25) in group 2 and 3.8% (n=10) in group 3. Table 1 shows the main results.

Conclusions

Elevation of both markers was found in almost 4% of patients. This elevation was associated with a higher E/e' ratio, E/A ratio, Letf Atrial Area and a lower S'-wave lateral.

Funding Acknowledgement

Type of funding source: None

P1811Association between the autonomic dysfunction and biomarker levels in patients with chagas disease without evidence of structural heart disease

Background

Several studies have shown autonomic dysfunction in early stages of Chagas disease (ChD). These alterations may be involved in the progression of the disease. The Valsalva Ratio (VR) is one of the most used tests to evaluate parasympathetic function, because it is easy and reproducible. On the other hand, the Higth Sensitive T troponin (HS-TnT) and the N-terminal pro B-type natriuretic peptide (NT-proBNP) are specific markers of myocardial damage and elevation of filling pressures, respectively. Both elevations are asociated with higher risk.

The association between autonomic dysfunction and biomarker levels in ChD without evidence of structural heart affection, has been poorly studied.

Purpose

The aim of this study is to evaluate the presence of abnormal VR as an expression of disanutonomy in patients with Chagas without evidence of structural heart disease and its association with HS-TnT and NT-proBNP levels.

Methods

A prospective study was performed, which included outpatients with positive serology for Chagas, with electrocardiogram, ergometry, holter and Doppler echocardiogram within normal parameters. The exclusion criteria were the following: history of ischemic heart disease, neurological diseases, chronic renal failure (clearence <30 ml/min), arterial hypertension and diabetes mellitus. All patients underwent a valsalva maneuver (VM), with continuous recording of the R-R interval by electrocardiogram. The VR was calculated dividing the longest RR interval after VM over the shortest RR interval during VM. Abnormal VR was considerated as a value <1.1. In addition, HS-TnT and NT-proBNP were measured in all patients.

Results

One hundred and forty four patients were included, with 45±8 years old, 44% fameles. The VR was 1.22±0.12, HS-TnT 6.44±3.8 ng/L and the NT-proBNP was 55±44 pg/ml. Abnormal VR was found in 29.1% of patients (n=42).

The abnormal VR group showed a higher level of HS-TnT (8.11±3.8 versus 5.7±3.5 ng/L, p=0.0006) and higher level of NT-proBNP (78±54 versus 45±36 pg/ml, p<0.0001). In addition, the abnormal VR group presented a greater E/e'ratio (9.48±2.5 versus 7.1±1.8, p<0.0001) and greater s wave (0.08±0.02 versus 0.10±0.02 cm/sec, p=0.02).

In the multivariate análisis, abnormal VR was asociated with higher HS-TnT (OR 1.22 (CI 95% 1.04–1.43), p=0.01) and higher E/e'ratio (OR 1.54 (CI95% 1.17–2.02), p=0.001), but not with NT-proBNP (p=0,09).

Conclusions

About one third of patients with ChD without evidence of cardiopaty had autonomic dysfunction. The patients with abnormal VR had higher leves of HS-TnT and NT-proBNP, but in the multivariate analisys only the HS-TnT had associated with abnormal VR.

Tumor infiltrating lymphocytes in acral lentiginous melanoma: a study of a large cohort of cases from Latin America

PURPOSE

Acral lentiginous melanoma (ALM) is a poor prognosis subtype and is the most prevalent in non-Caucasian populations. The presence of tumor infiltrating lymphocytes (TILs) has been associated with poor prognosis in melanoma. A large cohort of ALM cases was studied to determine status of TIL and its association with outcome.

METHODS

All patients with cutaneous melanoma presenting from 2005 to 2012 at Instituto Nacional de Enfermedades Neoplasicas in Peru were retrospectively identified. Clinicopathological information was obtained from the medical charts. A prospective evaluation of TIL was performed. Analysis of association between ALM and clinicopathological features including TIL as well as survival analysis compared the outcome of ALM to whole group and extremity NALM was performed.

RESULTS

537 ALM from a total of 824 cutaneous melanoma cases were studied. Older age (p = 0.022), higher Breslow (p = 0.008) and ulceration (p < 0.001) were found to be more frequent in ALM. Acral had worse overall survival (OS) compared with the whole group (p = 0.04). Clinical stage (CS) I-II patients had a median OS of 5.3 (95% CI 4.3-6.2) for ALM and 9.2 (95% CI 5.0-7.0) for extremity NALM (p = 0.016). Grade 0 (absence of TIL), I, II and III were found in 7.5, 34.5, 32.1, and 25.9%, respectively. Lower TIL grade was associated with larger tumor size (p = 0.003), higher Breslow (p = 0.001), higher Clark level (p = 0.007), higher CS (p = 0.002), extremity location (p = 0.048), histological subtype ALM (p = 0.024) and better OS (p = 0.001).

CONCLUSIONS

ALM is highly prevalent in Peru and carries poor outcome. Lower TIL levels were associated with poor outcome and ALM.

Abstract P5-09-08: Molecular evaluation of Peruvian patients with hereditary breast cancer reveals a novel germline mutation in BRCA1

Background

Breast cancer is the leading cancer in women worldwide, while in Peru is the second most frequent cancer with a high incidence of triple negative breast cancers (21%). There is no previous information about BRCA1/BRCA2 mutations in Peruvian high-risk breast cancer patients. Prior studies from International diagnostic laboratories only presented results of our population as a pooled Hispanic data. Our aim was to characterize mutations in BRCA1/BRCA2 genes in Peruvian patients with breast cancer with hereditary patterns.

Methods

We evaluated mutations in BRCA1/BRCA2 genes by Sanger sequencing and large genomic rearrangements by multiplex ligation-dependent probe amplification (MLPA) in 18 families with hereditary breast cancer criteria identified at the Breast Unit of Oncosalud-AUNA (Lima-Peru). Molecular analysis was done in the facilities of Genetics and Molecular Biology Center at the San Martin de Porres University (Lima-Peru).

Results

Sequencing identified 4 pathogenic mutations in 4/18 families, three previously detected (BRCA1: c.302-1G&gt;C y c.815_824dup10; BRCA2: c.5946delT) and a novel germline mutation in exon 15 of BRCA1 (c.4647_4648dupAA, ClinVar SCV000256598.1) producing a frameshift variant. MLPA revealed 2 amplifications in exon 7 (duplication and triplication) in BRCA1 in unrelated patients with potential pathogenic effects, one of this co-existed with the BRCA2: c.5946delT mutation. In addition, three variants of uncertain significance were found (c.140G&gt;T, in exon 5 of BRCA1 and c.464G&gt;A and c.938C&gt;T in exon 5 and 10 of BRCA2, respectively).

Conclusions

After a comprehensive evaluation we found an alteration rate of 27.8% (5/18) in BRCA1/BRCA2 in families with criteria for hereditary breast cancer. We reported BRCA1 c.4647_4648dupAA as a novel mutation. Further studies including a larger sample size of Peruvian patients should evaluate the prevalence or founder effect of this mutation in our population.

Citation Format: Ponce J, Vigil C, Araujo JM, Castañeda C, Calderon G, Buleje JL, Acosta O, Danos P, Huaman F, Guevara-Fujita ML, Aguilar A, Pinto JA, Gomez HL, Fujita R. Molecular evaluation of Peruvian patients with hereditary breast cancer reveals a novel germline mutation in BRCA1 [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P5-09-08.

Changes in the membrane carbohydrates from sperm cryopreserved with dimethylsulfoxide or polyvinylpyrrolidone of red-tailed hawk (Buteo jamaicencis)

BACKGROUND

That cryopreservation can induce alterations in sperm.

OBJECTIVE

The goal of this study was to evaluate sperm quality and distribution of N-acetylglucosamine, sialic acid and mannose residues in sperm cryopreserved of red-tailed hawk (Buteo jamaicensis).

MATERIALS AND METHODS

We studied twenty samples of ejaculated semen for each cryoprotectant dimethylsulfoxide or polyvinylpyrrolidone. Carbohydrate identification was carried out with lectins Triticum vulgaris agglutinin to N-acetylglucosamine and sialic acid and Concanavalia ensiformis for mannose residues. Sperm viability was not altered but motility decreased significantly with both crioprotectants compared with fresh sperm.

RESULTS

Neither the number of WGA positive sperm nor the distribution of N-acetylglucosamine and/or sialic acid residues were affected by the cryopreservation procedure. The sperm proportion with fluorescence associated with the presence of mannose residues was higher in thawed sperm.

CONCLUSION

Values obtained with the cryopreservation technique proposed in this study by freezing drops in liquid nitrogen, were within normal parameters established for good quality fresh semen. We can say that it can be used for assisted reproduction of Buteo jamaicensis.

Essential role of brain-derived neurotrophic factor in the regulation of serotonin transmission in the basolateral amygdala

Human and animal model studies have linked brain-derived neurotrophic factor (BDNF) with the etiology of anxiety disorders. This pleiotropic neurotrophin and its receptor, TrkB, promote neuronal survival, differentiation and synaptic plasticity. Here we interrogated the role of BDNF in serotonergic neurotransmission in the basolateral amygdala (BLA), a limbic brain region associated with the neurobiology of anxiety. We found that both GABAergic and pyramidal projection neurons in the wild-type BLA contained TrkB receptors. Examination of BDNF(2L/2LCk-Cre) mutant mice with brain-selective depletion of BDNF revealed mild decreases in serotonin content in the BLA. Notably, whole cell recordings in BLA pyramidal cells uncovered significant alterations in 5-HT(2)-mediated regulation of GABAergic and glutamatergic transmission in BDNF(2L/2LCk-Cre) mutant mice that result in a hyperexcitable circuit. These changes were associated with decreased expression of 5-HT(2) receptors. Collectively, the results indicate a required role of BDNF in serotonin transmission in the BLA. Furthermore, they suggest a mechanism underlying the reported increase in anxiety-like behavior elicited by perturbed BDNF signaling.

Smoking habits of parents and male: female ratio in spermatozoa and preimplantation embryos

BACKGROUND

Previous observations have addressed a decreased male:female ratio associated with smoking. Our aim was to assess whether this effect is observed at the spermatozoa or at the early embryo development.

METHODS

We retrospectively assessed smoking intake habits of 56 couples included in our preimplantation genetic diagnosis (PGD) program. Three groups were established according to male or female cigarette consumption per day: non-smokers, smokers (1-19 cigarettes per day) and heavy smokers (> or =20 cigarettes per day). Fluorescence in-situ hybridization (FISH) was performed on ejaculated sperm samples to analyse chromosomes X and Y. On day 3, embryos were also analysed. Additionally, sperm samples from four heavy smoking and four non-smoking donors were prospectively analysed before and after capacitation.

RESULTS

FISH on spermatozoa revealed no statistical differences in the Y:X ratio between the three groups. However, in the PGD study, in male heavy smokers, the XY:XX embryo ratio was decreased compared with non-smokers (22:47 versus 80:71; P = 0.0057). The smoking condition of the female partner had no significant effect on embryo XY:XX ratio, but for non-smoking females with a heavy smoking partner, the ratio was decreased (P = 0.0018) compared with non-smoking males. In heavy smoking donors a decreased of Y:X ratio was observed after swim-up with a statistically significant difference of ratios (P = 0.021).

CONCLUSIONS

Smoking habits of males do not have an effect on the percentage of X- and Y-bearing spermatozoa on ejaculated samples. However, male heavy smokers produce an increased incidence of female embryos that could be related to an enrichment of X spermatozoa after swim-up in patients with high tobacco consumption.

Developmental ability of chromosomally abnormal human embryos to develop to the blastocyst stage

BACKGROUND

A correlation between morphology, developmental competence and chromosome abnormalities is established. However, since absolute correlations are rare, embryo selection remains one of the most arduous tasks in assisted reproduction. This study was undertaken in order to determine which chromosomal abnormalities are compatible with development to the blastocyst stage.

METHODS

Embryos diagnosed by preimplantation genetic diagnosis (PGD) as chromosomally abnormal or unsuitable for transfer were cultured to day 5 or 6. Morphology and development were observed daily. After extended culture, embryos were fixed and analysed by two rounds of FISH with the same probes used for PGD.

RESULTS

Some types of numerical chromosome abnormalities do not preclude full differentiation in vitro. For instance, extensive mosaicism was detected in blastocysts and trisomic embryos reached the blastocyst stage with a frequency of 37%. Interestingly, only those monosomies compatible with first trimester development (monosomy X and 21) were detected at blastocyst stage.

CONCLUSION

Even though there is a strong selection against chromosomally abnormal embryos, extended culture to day 5 or 6 cannot be used as a reliable tool to select against clinically relevant chromosome abnormalities such as trisomies.

Cleavage anomalies in early human embryos and survival after prolonged culture in-vitro

This study examines the relationship between common morphological anomalies of cleaving embryos and their ability to form apparently normal blastocysts in vitro. The impact of cleavage rate, fragmentation, and multinucleation on compaction, cavitation, along with inner cell mass and trophectoderm formation has been assessed. The study population consisted of 102 patients who elected or were selected to have a day 5 embryo transfer. Clinical pregnancy and implantation rates were 66.7 and 49% respectively. Slow and fast cleavage had a significant negative association with normal blastocyst formation. Only 13.8% (67/484) of embryos with <7 cells and 27.5% (25/91) of those with >9 cells on day 3 formed blastocysts with apparently normal morphology, compared to 41.9% (252/602) with 7-9 cells on day 3 (P < 0.001). Fragmentation had a negative impact on normal blastocyst formation. Embryos with >15% fragmentation formed normal blastocysts at a significantly lower rate (46/279; 16.5%) than embryos with 0-15% fragmentation (311/935; 33.3%) (P < 0. 001). Furthermore, the pattern of fragmentation was associated with blastocyst formation. Type IV fragmentation led to a significant reduction in blastocyst formation (25/170 or 14.7%), compared to types I, II and III which performed much better (38.6, 32.9 and 32.4% respectively). Only 15.9% (22/138) of embryos with one or more multinucleate cells on day 2 and/or 3 formed normal blastocysts compared with 31.9% (335/1051) (P < 0.001) of those without multinucleation. Collectively, the data suggest that cleavage anomalies, some of which do not preclude development after short-term culture, may reduce the developmental competence of embryos after prolonged culture.

Randomized comparison of three media used for embryo culture after intracytoplasmic sperm injection

Since the metabolic requirements of fertilization and early embryonic development are very different, we have tested a new culture medium (EllioStep2, Ellios Bio-Media, Paris, France) specially designed for the first cleavages and compared it with two conventional media: BM1 (Ellios Bio-Media, Paris, France) and IVF50 (Scandinavian IVF Science, Gothenburg, Sweden). In order to avoid any interference with fertilization, the test was performed as part of an intracytoplasmic sperm injection (ICSI) study. A total of 416 ICSI attempts were randomly performed using one or other of the media. After sperm injection, oocytes were incubated either in EllioStep2 or in BM1 or in IVF50. The embryo quality, pregnancy and implantation rates, number of frozen embryos were compared in the different media. The percentage of fair embryos (grades 4 and 3) was significantly higher when EllioStep2 was used than when oocytes was cultured in BM1 medium (54 versus 47%; P < 0.01) or in IVF50 (69 versus 61%; P < 0.01). The pregnancy rate per transfer and the implantation rate were not significantly higher with EllioStep2 than with BM1 or IVF50. However, the percentage of embryo freezings per attempt was significantly higher with EllioStep2 than with BM1 (47/105 versus 28/105; P < 0.01). In conclusion, the use of EllioStep2 is associated with an increase in embryo quality permitting a higher number of embryo freezings.

Genetic diversity and epidemiology of hantaviruses in Argentina

Phylogenetic analysis of a 292-nucleotide (nt) fragment of the hantavirus M genome segment from 36 rodent and 13 human samples from three known foci of hantavirus infection in Argentina was conducted. A 1654-nt fragment of the M genome segment was analyzed for 1 representative of 7 genetically distinct hantavirus lineages identified. Additionally, the nt sequence of the complete M genome segments of Lechiguanas, Oran, and Hu39694 hantavirus genotypes was determined. nt sequence comparisons reveal that 7 hantavirus lineages from Argentina differ from each other by 11.5%-21.8% and from Sin Nombre, Bayou, and Black Creek Canal viruses by 23.8%-26.5%. Phylogenetic analyses demonstrate that they form a unique, separate branch within the clade containing other New World sigmodontine-borne hantaviruses. Most Oligoryzomys-borne hantavirus genotypes clearly map together. The Oligoryzomys-borne genotypes Lechiguanas, Oran, and Andes appear to be associated with human disease. Oligoryzomys longicaudatus was identified as the likely rodent reservoir for Andes virus.

An outbreak of hantavirus pulmonary syndrome, Chile, 1997

An outbreak of 25 cases of Andes virus-associated hantavirus pulmonary syndrome (HPS) was recognized in southern Chile from July 1997 through January 1998. In addition to the HPS patients, three persons with mild hantaviral disease and one person with asymptomatic acute infection were identified. Epidemiologic studies suggested person-to-person transmission in two of three family clusters. Ecologic studies showed very high densities of several species of sigmodontine rodents in the area.

Treatment of polycystic ovary patients undergoing IVF

We believe that PCO patients can achieve good results in IVF cycles, provided that stimulation protocols appropriate to their hormonal profiles are used.

The dose of gonadotropin used seems to be more important than the type of gonadotropin. If there is a risk of ovarian hyperstimulation, it is useful to employ one of the strategies recommended to prevent development of genuine OHS, which may endanger the patient’s health.

Impact of Asphaltene Presence in Some Rock Properties

Abstract

Several studies have shown that asphaltene precipitation at porous medium level leads to changes in some of its properties, such as wettability and hydraulic conductivity. This work shows the results obtained in a study aimed at assessing the effect of asphaltenes and its occasional precipitation on wettability and permeability of rocks found in Venezuelan oil reservoirs. Fluids and cores from five crude reservoirs having different asphaltene contents and Berea cores plugs were used. Wettability measurements were performed by using a variation of Amon method. Similarly, measurements were effected on cores in which precipitation was induced by n-pentane injection. Permeability reduction was evaluated by carrying out displacements tests before and after the precipitation induction.

All cases indicated the presence of changes in wettability. Such changes depend on the specific crude asphaltene content and always tend to an intermediate or preferential oil wettability condition, which does not increase during asphaltene precipitation.

Mean hydraulic radius reductions in tests where the precipitation was induced were in the range of 93.3 - 47%, which corresponded to asphaltene retention values of 19 and 3.6% PV, respectively. These reductions depend on the rock nature and the core properties: permeability, porosity and pore size distribution.

Introduction

Asphaltene deposition can occur during the production and processing of oils. This precipitate can reduce permeability, affect well injectivity and productivities, alter rock wettability and even cause plugging of wellbores, pipes and processing equipment. The approach followed in most of the published studies has been a remedial one and the development of the more desirable alternative of preventing the problem has lagged due in part to a lack of understanding of the mechanisms involved in the asphaltene deposition process.

Inside a reservoir, the asphaltene deposition is an even more complex phenomenon since it depends on a number of factors: the nature, saturation and distribution of the reservoir fluids, the mineralogy and properties of the rock, the pressure and temperature, the nature of injection fluids and the electrokinetic effects due to streaming potential generation due to reservoir fluid flow. Asphaltene can precipitate inside the reservoir as a result of changes in any of the factors listed above.

In this work, our efforts were geared toward the evaluation of the effect of asphaltenes (and its occasional precipitation) on wettability alteration and conductivity reduction of some rocks of Venezuelan asphaltene oil reservoir systems.

Effect of Asphaltenes on Rock Properties

Background. Before describing the effect of asphaltenes on rock properties, it is important to mention some characteristics of this material. The asphaltenes are complex molecules defined to be soluble in benzene and insoluble in low molecular weight n-alkanes and can be derived from petroleum, coal or shale oil. They are viewed as the most polar and highest molecular weight fraction of asphalt. Polarity of asphaltenes is due to the presence of hetero-atoms and condensed aromatic rings. The density of this molecule is approximately 1.2 g/cc, with a spherical shape range form 30 to 65 A in diameter. Asphaltenes in solution in the crude oil have been regarded by many researchers as a colloidal system. There are clear indications that asphaltenes are dispersed in the crude oil due to the resins. Resins act as peptizing agents for the asphaltenes. Both asphaltenes and resins have a tendency to aggregate with each other. The degree of aggregation depends on the aromaticity and the chemical composition of the oil.

Any action of chemical, electrical or mechanical nature that depeptizes the asphaltene micelle lead to flocculation and precipitation of asphaltenes from the crude oil. It is important to note here that asphaltene flocculation and deposition are two separate phenomena. It is possible to have flocculation without substantial in situ deposition. After flocculation, the asphaltenes aggregates may be brought into contact with the possible retention site on the rock surface.

Optimization of implantation in the in-vitro fertilization laboratory

Implantation failure rates after in-vitro fertilization (IVF) can be reduced in the IVF laboratory using two different techniques: assisted hatching and embryo co-culture on monolayer feeder cells. A review of the different methodologies and the results gained using these techniques is reported. Preliminary results obtained in the Reproductive Medicine Service of the Institut Universitari Dexeus, Barcelona, Spain using these techniques are also presented.

[Results of conjugal artificial insemination using Percoll]

Selection of spermatozoa on Percoll's medium has enabled to obtain 33 pregnancies in 217 couples. This simple and inexpensive technique, which is most successful during the first nine months, deserves to be attempted, in case of deficient sperm, before contemplating more complex techniques.

Production of specific retinal S antigen antibodies in patients with retinal detachment

One hundred patients with retinal detachment (61 primary operations and 39 reoperations) were studied for titers of autoantibodies to human retinal S antigen using the enzyme-linked immunosorbent assay technique (ELISA). There was no statistically significant difference when comparing the group of patients with primary retinal detachment with the control group. However, a statistically significant increase in anti-S titers was recorded when a comparison was made between the group of reoperated patients and the control group (chi 2, P less than 0.001) and between the group of reoperated subjects and the group of patients operated on for the first time (chi 2, P less than 0.005).

Are clinical and biological IVF parameters correlated with chromosomal disorders in early life: a multicentric study

A multicentric study was carried out to analyse in a large series: (i) the chromosomal status of unfertilized oocytes, (ii) errors at fertilization and (iii) the chromosomal complement of cleaved embryos. Parameters such as type of sterility, maternal age, stimulation treatment, doses of gonadotrophins administered and oocyte preincubation time before insemination were studied in relation to the incidence of chromosome abnormalities. Twenty-six per cent of the unfertilized oocytes and 29.2% of the embryos had chromosome anomalies. Maternal age significantly increased the rate of aneuploidy in oocytes: 38% in patients over 35 years (versus 24% in younger patients). Fertilization-related abnormalities were significant, i.e. 1.6% parthenogenesis and 6.4% polyploidy. Unexplained infertility was correlated with an increase in the rate of parthenogenesis (4.2%) when compared with tubal infertility (1.2%). Triploidy was found to be correlated with three parameters. A lower rate of triploidy was observed in the group of couples referred because of male sterility (1.9% versus 6.3% for tubal sterility), in HMG-treated patients (2.4% versus 7% with analogues of LHRH/HMG) and with a short 2-h preincubation time before insemination (3% versus 7.2% for greater than 2 h). A general model for natural selection against embryos carrying a chromosome imbalance was proposed.

Pregnancy after the replacement of a frozen-thawed embryo with less than 50% intact blastomeres

Early embryo freezing with saccharose and propanediol gives a survival rate of 62% of the embryos if 4 cell embryos with only one intact blastomere after thawing are included. The first pregnancy achieved with such an embryo is reported as well as preliminary results obtained in our IVF programme using the French method.