Bidirectional light-induced conductance switching in molecular wires containing a dimethyldihydropyrene unit.

Photochromic coordination polymers, based on zinc(ii) bis-terpyridine-appended dimethyldihydropyrene building blocks, have been synthesized following stepwise synthesis on a surface yielding photo-switchable molecular junctions. Under irradiation, reversible structural changes occur by the isomerization of the photosensitive units, thus inducing conductance switching of the molecular junctions with a good reproducibility.

LDSO: a program to simulate pedigrees and molecular information under various evolutionary forces.

Simulations are a major tool to evaluate new statistical methods and optimize experimental designs in the genomic era. However, this can only be achieved when the simulations are close enough to reality, as well as diverse enough to be realistic. For mapping studies, it is thus critical to re-create as much as possible the forces generating linkage (mutation, random drift, changes in population sizes, selection and pedigree structure) and the mechanisms producing trait genetic architecture (additivity, dominance, epistasis). We present here a computer program (ldso) simulating these phenomena. Optional outputs provide statistics on the linkage disequilibrium (LD) structure and the identity by descent between chromosomal segments, facilitating further data analyses. Furthermore, ldso enables the simulation of genomic data in known pedigrees, which sticks as precisely as possible to recent population history and structures of the long-range LD, allowing optimization of fine-mapping strategies.

Merino sheep: a further look at quantitative trait loci for wool production.

A quantitative trait loci (QTL) analysis of wool traits from experimental half-sib data of Merino sheep is presented. A total of 617 animals distributed in 10 families were genotyped for 36 microsatellite markers on four ovine chromosomes OAR1, OAR3, OAR4 and OAR11. The markers covering OAR3 and OAR11 were densely spaced, at an average distance of 2.8 and 1.2 cM, respectively. Body weight and wool traits were measured at first and second shearing. Analyses were conducted under three hypotheses: (i) a single QTL controlling a single trait (for multimarker regression models); (ii) two linked QTLs controlling a single trait (using maximum likelihood techniques) and (iii) a single QTL controlling more than one trait (also using maximum likelihood techniques). One QTL was identified for several wool traits on OAR1 (average curvature of fibre at first and second shearing, and clean wool yield measured at second shearing) and on OAR11 (weight and staple strength at first shearing, and coefficient of variation of fibre diameter at second shearing). In addition, one QTL was detected on OAR4 affecting weight measured at second shearing. The results of the single trait method and the two-QTL hypotheses showed an additional QTL segregating on OAR11 (for greasy fleece weight at first shearing and clean wool yield trait at second shearing). Pleiotropic QTLs (controlling more than one trait) were found on OAR1 (clean wool yield, average curvature of fibre, clean and greasy fleece weightand staple length, all measured at second shearing).

QTL detection for milk production traits in goats using a longitudinal model.

Eight paternal half-sib families were used to identify chromosomal regions associated with variation in the lactation curves of dairy goats. DNA samples from 162 animals were amplified by PCR for 37 microsatellite markers, from Capra hircus autosomes CHI3, CHI6, CHI14 and CHI20. Milk samples were collected during 6 years, and there were 897 records for milk yield (MY) and 814 for fat (FP) and protein percentage (PP). The analysis was conducted in two stages. First, a random regression model with several fixed effects was fitted to describe the lactation function, using a scale (alpha) plus four shape parameters: beta and gamma, both associated with a decrease in the slope of the curve, and delta and phi that are related to the increase in slope. Predictions of alpha, beta, gamma, delta and phi were regressed using an interval mapping model, and F-tests were used to test for quantitative trait loci (QTL) effects. Significant (p < 0.05) QTLs were found for: (i) MY: CHI6 at 70-80 cM for all parameters; CHI14 at 14 cM for delta and phi; (ii) FP: CHI14, at 63 cM was associated with beta; CHI20, at 72 cM, showed association with alpha; (iii) PP: chromosomal regions associated with beta were found at 59 cM in CHI3 and at 55 cM in CHI20 with alpha and gamma. Analyses using more families and more animals will be useful to confirm or to reject these findings.

[Complications at the first month following various types of intracoronary stents, implanted with high pressure without intracoronary ultrasonography or anticoagulation]. / Complicaciones en el primer mes de varios tipos de stents intracoronarios, implantados a altas presiones sin ayuda de ultrasonidos intracoronarios ni anticoagulación.

BACKGROUND: Coronary stents have proved their efficacy in bail-out situations and restenosis. Nevertheless, the high incidence of subacute thrombosis and vascular and bleeding complications limits its use. OBJECTIVES: To evaluate the clinical complications during the first month of three different types of stents, implanted with high pressure, without ultrasound guidance or anticoagulation. PATIENTS AND METHODS: All stents were implanted in arteries of 3 mm or more. After implantation, all stents were dilated between 15-17 atmospheres, aiming to a residual stenosis lower than 10%. After implantation, all patients received aspirin indefinitely and ticlopidine 250 mg twice daily for one month. The initial success, the ischemic complications (death, myocardial infarction and emergency surgery), acute and subacute thrombosis and vascular and hemorrhagic complications were evaluated. The evaluation was done following the procedure, prior to discharge from the hospital and at 1 month follow-up. RESULTS: In 49 patients, 51 stents were implanted. 70% had unstable angina. In one case the stent was implanted after primary PTCA. In 17.6%, the stent was implanted in a bail-out situation. Of the 51 stents, 32 were Palmaz-Schatz, 12 Wiktor and 7 Gianturco-Roubin. The initial success was 100%. There were no deaths, AMI, nor emergency surgeries in the first month. There was no case of acute or subacute thrombosis. There were 2 minor complications; one vascular: a pseudoaneurysm, and another hemorrhagic: an inguinal hematoma. Neither case needed surgery nor blood transfusion. All patients were discharged within 48 hours. CONCLUSION: Implantation of stents with high pressures, in spite of not using guidance ultrasound nor anticoagulation, is safe and effective, with a clear decrease in vascular complications, and without an increase in the incidence of acute or subacute thrombosis.

[Electrocardiographic differences between standard 12-lead recording and modifications in exercise testing]. / Diferencias electrocardiográficas entre el registro estándar de 12 derivaciones y el modificado para prueba de esfuerzo.

Modified limb electrode positions proposed by Mason and Likar are often used in exercise electrocardiograms. In some cases, such modifications induced considerable differences in electrocardiographic waveforms of the frontal plane leads. To assess the magnitude of these changes, 55 patients were studied with standard and modified limb electrodes. We observed a significant verticalization (p less than 0.01) of all electrical axis in the modified ones: there was a difference of 19.6 +/- 1.7 grades for the P wave, 36.4 +/- 8 grades for the QRS axis and 26.0 +/- 3.3 for the T wave in the frontal plane. When classified by electrocardiographic pathology, old transmural inferior myocardial infarction and S1, S2, S3 pattern did not change electrical axis. There was also a significant increase (5 +/- 1 mseg, p less than 0.01) in the intrinsic deflection onset of the unipolar lead a VF of the modified one. Such finding suggests the recording of a more lateral region when compared with the onset of intrinsic deflection of the precordial leads. We conclude that modified limb electrode position induces a significant verticalization of the electrical axis in the frontal plane. The recorded myocardial region in such electrocardiograms seems to be different from that recorded in the standard one. For some cases, we suggest to explore the inferior myocardial region by using the standard aVF location in the postexercise recordings.

[The spontaneous regression of a rhabdomyoma of the right ventricle]. / Regresión espontánea de un rabdomioma de ventrículo derecho.

Rhabdomyoma is the most common intracardiac tumor in the newborn. The diagnosis is made by the clinical history and the physical examination, the electrocardiogram, chest X-ray, and the echocardiographic data. It has a poor prognosis, 80% dying in the first year of life because congestive heart failure or sudden death. Rarely, spontaneous regression has been described. We present the case of a newborn diagnosed of tuberous sclerosis, with an echocardiographic image of a rhabdomyoma in the right ventricle with a spontaneous total regression of the tumor 2 years later.

[Pericardial effusion simulating a tumor. The value of Doppler color echocardiography for its differentiation]. / Derrame pericárdico que simula un tumor. Valor de la ecocardiografía Doppler a color para su diferenciación.

We describe the case of a patient aged 64 with aortic valve disease and pericardial effusion. Echocardiographic evaluation showed an intrapericardial mass of about 7 cm of diameter with clotted appearance, adhered to the visceral leaf, at the level of the atrio-ventricular function. Because of this finding we performed color codified Doppler echocardiography, observing that this mass acquired a blue hue during diastole and mosaic hue at the end of the systole, realizing that this phenomenon was due to fluid retention. There are many publications about the value of echocardiography for the identification of pericardial masses and some of them show how an effusion can hide a tumor. The interest of this particular case lies in that the effusion simulated a tumor and by means of the color codified Doppler we could demonstrate that it corresponded to the stream of the pericardial fluid. During the surgical procedure the absence of the mass was corroborated.

[Exercise test with cold water intake. Preliminary results]. / Prueba de esfuerzo con ingestión de agua fría. Resultados preliminares.

Thirty healthy individuals with no history of cardiovascular disease were studied to determine the electrocardiographic effects of maximal exercise immediately followed by ingestion of ice water. The subjects were subgrouped according to their training into (A) high (N = 5), (B) moderate (N = 14) and (C) low (N = 11) levels. Electrocardiograms (ECGs) were taken at rest and at rest with ingestion of ice water followed by maximal stress tests. Maximal stress tests were repeated followed by ingestion of ice water at the beginning of and at 2, 3, 6 and 9 minutes of recuperation. The stress test combining maximal effort and ice water ingestion was positive in all members of Group A, in 4 from Group B and in 1 from Group C. A stress test associating maximal effort with ice water ingestion is a useful method of detecting subjects susceptible to changes in ECG which appear to be secondary to coronary spasm. It has a low cost it is simple to perform and represents minimal risk.