Museomics Dissects the Genetic Basis for Adaptive Seasonal Coloration in the Least Weasel.

Dissecting the link between genetic variation and adaptive phenotypes provides outstanding opportunities to understand fundamental evolutionary processes. Here, we use a museomics approach to investigate the genetic basis and evolution of winter coat coloration morphs in least weasels (Mustela nivalis), a repeated adaptation for camouflage in mammals with seasonal pelage color moults across regions with varying winter snow. Whole-genome sequence data were obtained from biological collections and mapped onto a newly assembled reference genome for the species. Sampling represented two replicate transition zones between nivalis and vulgaris coloration morphs in Europe, which typically develop white or brown winter coats, respectively. Population analyses showed that the morph distribution across transition zones is not a by-product of historical structure. Association scans linked a 200-kb genomic region to coloration morph, which was validated by genotyping museum specimens from intermorph experimental crosses. Genotyping the wild populations narrowed down the association to pigmentation gene MC1R and pinpointed a candidate amino acid change cosegregating with coloration morph. This polymorphism replaces an ancestral leucine residue by lysine at the start of the first extracellular loop of the protein in the vulgaris morph. A selective sweep signature overlapped the association region in vulgaris, suggesting that past adaptation favored winter-brown morphs and can anchor future adaptive responses to decreasing winter snow. Using biological collections as valuable resources to study natural adaptations, our study showed a new evolutionary route generating winter color variation in mammals and that seasonal camouflage can be modulated by changes at single key genes.

The evolutionary pathways for local adaptation in mountain hares.

Understanding the evolution of local adaptations is a central aim of evolutionary biology and key for the identification of unique populations and lineages of conservation relevance. By combining RAD sequencing and whole-genome sequencing, we identify genetic signatures of local adaptation in mountain hares (Lepus timidus) from isolated and distinctive habitats of its wide distribution: Ireland, the Alps and Fennoscandia. Demographic modelling suggested that the split of these mountain hares occurred around 20 thousand years ago, providing the opportunity to study adaptive evolution over a short timescale. Using genome-wide scans, we identified signatures of extreme differentiation among hares from distinct geographic areas that overlap with area-specific selective sweeps, suggesting targets for local adaptation. Several identified candidate genes are associated with traits related to the uniqueness of the different environments inhabited by the three groups of mountain hares, including coat colour, ability to live at high altitudes and variation in body size. In Irish mountain hares, a variant of ASIP, a gene previously implicated in introgression-driven winter coat colour variation in mountain and snowshoe hares (L. americanus), may underlie brown winter coats, reinforcing the repeated nature of evolution at ASIP moulding adaptive seasonal colouration. Comparative genomic analyses across several hare species suggested that mountain hares' adaptive variants appear predominantly species-specific. However, using coalescent simulations, we also show instances where the candidate adaptive variants have been introduced via introgressive hybridization. Our study shows that standing adaptive variation, including that introgressed from other species, was a crucial component of the post-glacial dynamics of species.

Accelerated synthesis of phthalimide derivatives: Intrinsic reactivity of diamines towards phthalic anhydride evaluated by paper spray ionization mass spectrometry.

RATIONALE: Paper spray (PS) is a simple and innovative ambient ionization technique for mass spectrometry (MS) analysis. Under PS-MS conditions, chemical reactions, which usually occur slowly on a bulk scale, are accelerated. Moreover, the formation of products and transient species can be easily monitored. In this manuscript, reactions between phthalic anhydride and diamines were conducted and monitored using a PS-MS platform. The reaction products (phthalimides) have many pharmaceutical applications, but their traditional syntheses can take hours under reflux, requiring laborious purification steps. METHODS: In situ reactions were performed by dropping methanolic solutions of phthalic anhydride and diamines on a triangular paper. The analyses were achieved by positioning the triangle tip in front of the mass spectrometer entrance, whereas a metal clip was attached to the triangle base. After adding methanol to the paper, a high voltage was applied across the metal clip, and the mass spectra were acquired. RESULTS: The intrinsic reactivity of alkyl and aromatic diamines was evaluated. The carbon chain remarkably influenced the reactivity of aliphatic diamines. For aryl diamines, the ortho isomer was the most reactive. Moreover, for aryl amines with electron-withdrawing substituents, no reaction was noticed. CONCLUSIONS: Taking advantage of the unique characteristics of PS-MS, it was possible to investigate the intrinsic reactivity of model alkyl (ethylene versus propylene) and aryl (o-phenylene versus m-phenylene and p-phenylene) diamines towards phthalic anhydride. Some crucial parameters that affect the intrinsic reactivity of organic molecules, such as isomerism, intramolecular interaction, and conformation, were easily explored.

Introgression drives repeated evolution of winter coat color polymorphism in hares.

Changing from summer-brown to winter-white pelage or plumage is a crucial adaptation to seasonal snow in more than 20 mammal and bird species. Many of these species maintain nonwhite winter morphs, locally adapted to less snowy conditions, which may have evolved independently. Mountain hares (Lepus timidus) from Fennoscandia were introduced into the Faroe Islands in 1855. While they were initially winter-white, within ∼65 y all Faroese hares became winter-gray, a morph that occurs in the source population at low frequency. The documented population history makes this a valuable model for understanding the genetic basis and evolution of the seasonal trait polymorphism. Through whole-genome scans of differentiation and single-nucleotide polymorphism (SNP) genotyping, we associated winter coat color polymorphism to the genomic region of the pigmentation gene Agouti, previously linked to introgression-driven winter coat color variation in the snowshoe hare (Lepus americanus). Lower Agouti expression in the skin of winter-gray individuals during the autumn molt suggests that regulatory changes may underlie the color polymorphism. Variation in the associated genomic region shows signatures of a selective sweep in the Faroese population, suggesting that positive selection drove the fixation of the variant after the introduction. Whole-genome analyses of several hare species revealed that the winter-gray variant originated through introgression from a noncolor changing species, in keeping with the history of ancient hybridization between the species. Our findings show the recurrent role of introgression in generating winter coat color variation by repeatedly recruiting the regulatory region of Agouti to modulate seasonal coat color change.

Physical characterization of 3 implant systems made of distinct materials with distinct surfaces.

STATEMENT OF PROBLEM: Dental implants undergo various surface treatments. Studies that have characterized their surface and subsurface by using the same methods are scarce. PURPOSE: The purpose of this study is to physically characterize the surface and subsurface of implant systems made of commercially pure (cp) titanium (Ti) grade (gr) 4 and Ti alloy gr 23 and to evaluate whether airborne-particle abrasion and acid etching is an appropriate surface treatment for Ti alloy gr 23. MATERIAL AND METHODS: Implant groups (n=3) were as follows: TG4AO, cp Ti gr 4, treated with anodic oxidation (3.5×8 mm) (NobelReplace Conical; Nobel Biocare); TG23AE, Ti gr 23 (TiAlV ELI) airborne-particle abraded-and-etched (3.9×8 mm) (V3; MIS); and TG4AE, cp Ti gr 4, airborne-particle abraded and etched (3.3×8 mm) (BL; Institut Straumann AG). Surface roughness, surface topography, and elemental and surface composition were investigated with optical profilometry, scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction. The presence and size of Ti hydride (TiH) needles were determined on metallographic sections. Depth profiling was obtained by time-of-flight secondary ion mass spectrometry (ToF-SIMS) to determine possible enrichment of an alloying element at the implant surface. RESULTS: The mean arithmetic deviation roughness (Sa), of TG4AO was 0.80 µm. The Sa of TG4AO was 1.22 µm, and the Sa of TG4AO was 1.59 µm. The difference between the groups was significant (P<.001). TG23AE and TG4AE displayed a macrotexture and microtexture with pores; TG4AO showed a 3-to 12-µm canyon-like structure. The surface and subsurface compositions were as follows: for TG4AO, αTi and phosphorus-rich anatase; for TG23AE, α-Ti matrix with ß-Ti grains; and for TG4AE, α-Ti and δ-TiH2-x. TiH needles were found only on TG4AE; the Ti oxide layer of TG4AO was rough, 3-to 16-µm thick, and porous. The time-of-flight secondary ion mass spectrometry (ToF SIMS) concentration profile of TG23AE did not show enrichment of any alloying element. CONCLUSIONS: The roughness, topography, and composition of the surfaces were different for all implants tested. Airborne-particle abrasion and subsequent etching was an appropriate treatment for Ti gr 23 alloy implants.

Evaluating the Neolithic Expansion at Both Shores of the Mediterranean Sea.

During the Neolithic, human populations underwent cultural and technological developments that led to an agricultural revolution. Although the population genetics and evolution of European Neolithic populations have been extensively studied, little is known regarding the Neolithic expansion in North Africa with respect to Europe. One could expect that the different environmental and geological conditions at both shores of the Mediterranean Sea could have led to contrasting expansions. In order to test this hypothesis, we compared the Neolithic expansion in Europe and North Africa accounting for possible migration between them through the Strait of Gibraltar. We analyzed the entire X chromosome of 580 individuals from 20 populations spatially distributed along the North of Africa and Europe. Next, we applied approximate Bayesian computation based on extensive spatially explicit computer simulations to select among alternative scenarios of migration through the Strait of Gibraltar and to estimate population genetics parameters in both expansions. Our results suggest that, despite being more technologically advanced, Neolithic populations did not expand faster than Paleolithic populations, which could be interpreted as a consequence of a more sedentary lifestyle. We detected reciprocal Neolithic migration between the Iberian Peninsula and North Africa through the Strait of Gibraltar. Counterintuitively, we found that the studied Neolithic expansions presented similar levels of carrying capacity and migration, and occurred at comparable speeds, suggesting a similar demic process of substitution of hunter-gatherer populations. Altogether, the Neolithic expansion through both Mediterranean shores was not so different, perhaps because these populations shared similar technical abilities and lifestyle patterns.

Did the Romans introduce the Egyptian mongoose (Herpestes ichneumon) into the Iberian Peninsula?

New finds of bones of the Egyptian Mongoose (Herpestes ichneumon), one from Portugal and one from Spain, were directly 14C dated to the first century AD. While the Portuguese specimen was found without connection to the Chalcolithic occupation of the Pedra Furada cave where it was recovered, the Spanish find, collected in the city of Mérida, comes from a ritual pit that also contained three human and 40 dog burials. The finds reported here show that the Egyptian mongoose, contrary to the traditional and predominant view, did not first arrive in the Iberian Peninsula during the Muslim occupation of Iberia. Instead, our findings are consistent with the hypothesis that the species was first introduced by the Romans, or at least sometime during the Roman occupation of Hispania. Therefore, radiocarbon dating of new archaeological finds of bones of the Egyptian Mongoose (Herpestes ichneumon) in the Iberian Peninsula push back the confirmed presence of the species in the region by approximately eight centuries, as the previously oldest dated record is from the ninth century. With these new dates, there are now a total of four 14C dated specimens of Egyptian mongooses from the Iberian Peninsula, and all of these dates fall within the last 2000 years. This offers support for the hypothesis that the presence of the species in Iberia is due to historical introductions and is at odds with a scenario of natural sweepstake dispersal across the Straits of Gibraltar in the Late Pleistocene (126,000-11,700 years ago), recently proposed based on genetic data.

Diversity in the androgen receptor CAG repeat has been shaped by a multistep mutational mechanism.

The androgen receptor (AR) gene encodes a type of nuclear receptor that functions as a steroid-hormone activated transcription factor. In its coding region, AR includes a CAG repeat, which has been intensely studied due to the inverse correlation between repeat size and AR transcriptional activity. Several studies have reported different (CAG)n sizes associated with the risk of androgen-linked diseases. We aimed at clarifying the mechanisms on the origin of newly CAG sized alleles through a strategy involving the analysis of the associated haplotype diversity. We genotyped 374 control individuals of European and Asian ancestry, and reconstructed the haplotypes associated with the CAG repeat, defined by 10 SNPs and 6 flanking STRs. The most powerful SNPs to tag AR lineages are rs7061037-rs12012620 and rs34191540-rs6625187-rs2768578 in Europeans and Asians, respectively. In the most frequent AR lineage, (CAG)18 alleles seem to have been generated by a multistep mutation mechanism, most probably from longer alleles. We further noticed that the DXS1194-DXS1111 haplotype, in linkage disequilibrium with AR-(CAG)n expanded alleles responsible for spinal bulbar muscular atrophy (SBMA), is rare among our controls; however, the haplotype strategy here described may be used to clarify the origin of expansions in other populations, as in future association studies.

Multi-component adsorption study by using bone char: modelling and removal mechanisms.

Highly efficient simultaneous removal of paracetamol and Cu2+ ions from aqueous solutions was accomplished by using bovine bone char (BC). The adsorption behaviour was determined by kinetic and equilibrium studies of both single and binary system solutions. BC is a predominantly mesoporous material with a surface area of 103 m2 g-1. The influence of the initial pH on Cu2+ removal was tested, suggesting that the optimal pH was 3.0. The removal of paracetamol from single and binary systems was 9.45 and 12.7%, respectively. On the other hand, the Cu2+ removal was 36.2% for a single system, suggesting a higher affinity for BC. Moreover, in the case of binary mixtures, the presence of paracetamol led to an enhanced affinity of Cu2+ due to a synergistic/cooperative mechanism, which led to a copper removal of 97.3%. The cooperative model was successfully adjusted to the equilibrium data of the binary systems. The modelling results indicated the formation of a first adsorption layer where paracetamol and copper are retained, and a second layer with a great affinity for copper ions after the formation of a Cu-paracetamol complex, leading to higher removal of Cu2+.

On-Surface Alcohol Oxidation Monitored by Paper Spray Mass Spectrometry: The Role of Ruthenium as Catalyst.

Paper spray ionization mass spectrometry (PS-MS) is employed herein as a convenient platform to investigate an on-surface catalytic process, that is, the oxidation of alcohols induced by ruthenium salts. The tag-charged benzyl alcohol 1 (m/z 166), used as a suitable prototype starting substrate, is quickly oxidized by tert-butyl hydroperoxide (TBHP) in an on-surface process catalyzed by ruthenium trichloride (RuCl3). The PS(+)-MS revealed the formation of products from the oxidation of alcohol 1. RuCl3 and TBHP played a crucial role in this process since when salts of other metals (platinum, palladium, and iron) and another oxidizing agent (hydrogen peroxide) are employed, no reaction is observed. Moreover, UV radiation and heating accelerate the on-surface alcohol 1 oxidation. Finally, an exciting possibility is to employ PS-MS to investigate similar organic catalytic reactions to accelerate them and detect unstable intermediates, indiscernible in the condensed phase.

Comparison of birth weight, length, and head circumference between the BRISA-RP and Intergrowth-21st cohorts.

OBJECTIVES: (a) To determine the 3rd, 50th, and 97th percentiles of weight, length, and head circumference of newborns from the Ribeirão Preto BRISA cohort, according to gender and gestational age, and compare them with the Intergrowth-21st standard; (b) To estimate the small for gestational age (<3rd percentile), large for gestational age (>97th percentile), stunting (length<3rd percentile), and wasting (body mass index<3rd percentile). METHODS: Observational study of a cohort of 7702 newborns between 01/01/2010 and 12/31/2010 in the city of Ribeirão Preto, SP, Brazil. The 3rd, 50th, and 97th percentiles were determined for the anthropometric measurements using fractional polynomial regression. RESULTS: The weight difference between Ribeirão Preto and Intergrowth-21st was small, being more pronounced in preterm infants (mean difference between the two populations of +266g); for full-term newborns, there was a mean difference of +66g, and for post-term infants, of -113g. For length, the mean variation was always <1cm; whereas for head circumference, preterm newborns showed a variation >1cm, and full-term and post-term newborns showed a variation of <1cm. The small and large for gestational age detection rates were 2.9% and 4.3%, respectively. Stunting affected 6.5% of all newborns and wasting, 1.5%, with a predominance in girls and in full-term pregnancies; both conditions were present in 0.4% of the sample. CONCLUSIONS: Newborns from Ribeirão Preto, when compared to the Intergrowth-21 standard, are heavier, longer, and have a larger head circumference until they reach full-term.

Coronary Sinus Phlebography in Cardiac Resynchronization Therapy Patients: Identifying and Solving Demanding Cases.

Cardiac resynchronization therapy (CRT) improves symptoms and reduces morbidity and mortality in select heart failure patients but remains challenging to deploy widely because of difficult or unsuccessful coronary sinus (CS) access in up to 10% to 15% of patients. This report describes the radiological and anatomical aspects for improving CS catheterization and left ventricular (LV) lead positioning, focusing on the radioscopic and anatomical aspects, based on phlebography, to identify demanding cases in patients with dilated cardiomyopathy referred for CRT implantation. Anatomical and radiological aspects were explored in the anteroposterior, 30° left anterior oblique, and 30° right anterior oblique (RAO) views. In total, 117 phlebographies were performed in 39 consecutive procedures (one reintervention). Access to the CS was successful 37 times (94.9%). The most difficult cases were complicated by issues related to the altered spatial orientation of the CS ostium toward the tricuspid annular plane (TAP), which was best perceived in the 30° RAO projection and occurred in 37% of patients. One of two catheterization failures that occurred was caused by anomalous coronary venous drainage into the left atrium. Final LV lead positioning was successful in 36 (92.3%) of 39 procedures. More severe heart failure and worse LV ejection fraction did not translate into greater difficulty in LV lead implantation. As such, understanding anatomical and radiological relationships is the key to successful LV lead positioning. RAO projection can be particularly useful in the assessment of demanding CRT implant cases, especially when the CS ostium pointed to the TAP.

Advanced Mechanochemistry Device for Sustainable Synthetic Processes.

Mechanochemistry is an alternative for sustainable solvent-free processes that has taken the big step to become, in the near future, a useful synthetic method for academia and the fine chemical industry. The apparatus available, based on ball milling systems possessing several optimizable variables, requires too many control and optimization experiments to ensure reproducibility, which has limited its widespread utilization so far. Herein, we describe the development of an automatic mechanochemical single-screw device consisting of an electrical motor, a drill, and a drill chamber. The applicability and versatility of the new device are demonstrated by the implementation of di- and multicomponent chemical reactions with high reproducibility, using mechanical action exclusively. As examples, chalcones, dihydropyrimidinones, dihydropyrimidinethiones, pyrazoline, and porphyrins, were synthesized with high yields. The unprecedented sustainability is demonstrated by comparison of EcoScale and E-factor values of these processes with those previously described in the literature.

Can hypoglycemic episodes in type 1 diabetics trigger cardiac arrhythmias?

BACKGROUND: Sudden nocturnal death is a syndrome that usually affects patients with diabetes mellitus type 1 (DM1), being described mainly due to ventricular arrhythmias in response to nocturnal hypoglycemia. OBJECTIVES: Evaluate the relation between hypoglycemia and ventricular arrhythmias in patients with DM1 and normal structural heart. METHOD: Prospective, observational study with DM1 patients and normal structural heart on echocardiogram aged 18-60 years, of both sexes receiving insulin therapy for at least five years. Intermittent glucose reading device was implanted (iPro2 - Medtronic/USA) and 24hr ambulatory electrocardiographic recording by the Holter system (Cardios Systems - Brazil). Patients were monitored for hypoglycemia without any type of induction (interstitial glucose <70 mg/dl) and cardiac arrhythmias within 24 h. RESULTS: Thirty-two patients were evaluated, with mean-age of 35 years, being 16 men. Eleven patients (34%) did not have hypoglycemia, other 3 (27.3%) also had no arrhythmia, while 8 (72.7%) had arrhythmias interpreted as irrelevant. The other 21 patients (66%) presented some hypoglycemic episodes and 10 (47.6%) did not present arrhythmias, whereas 11 (52.4%) presented arrhythmias considered not clinically significant, as also found in non-diabetic individuals. CONCLUSION: In patients with DM1 without structural heart disease there was no relationship between cardiac arrhythmia and episodes of hypoglycemia.

Spatially explicit analysis reveals complex human genetic gradients in the Iberian Peninsula.

The Iberian Peninsula is a well-delimited geographic region with a rich and complex human history. However, the causes of its genetic structure and past migratory dynamics are not yet fully understood. In order to shed light on them, here we evaluated the gene flow and genetic structure throughout the Iberian Peninsula with spatially explicit modelling applied to a georeferenced genetic dataset composed of genome-wide SNPs from 746 individuals belonging to 17 different regions of the Peninsula. We found contrasting patterns of genetic structure throughout Iberia. In particular, we identified strong patterns of genetic differentiation caused by relevant barriers to gene flow in northern regions and, on the other hand, a large genetic similarity in central and southern regions. In addition, our results showed a preferential north to south migratory dynamics and suggest a sex-biased dispersal in Mediterranean and southern regions. The estimated genetic patterns did not fit with the geographical relief of the Iberian landscape and they rather seem to follow political and linguistic territorial boundaries.

Isolation of Cryptococcus species from the external environments of hospital and academic areas.

INTRODUCTION: Fungi of the genus Cryptococcus are cosmopolitan and may be agents of opportunistic mycoses in immunocompromised and sometimes immunocompetent individuals. Cryptococcus species are frequently isolated from trees and bird excreta in the environment and infection occurs by inhalation of propagules dispersed in the air. The aim was to investigate Cryptococcus species in bird excreta and tree hollows located in a university hospital area and in an academic area of a university campus. METHODOLOGY: A total of 40 samples of bird excreta and 41 samples of tree hollows were collected. The identification of the isolates was done by classical methodology and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. RESULTS: Twenty (62.5%) isolates of Cryptococcus were found in bird excreta and 12 (37.5%) in tree hollows. C. laurentii (currently Papiliotrema laurentii) was the most frequent species in both samples, being found in 5 samples of excreta and in 8 tree hollows. The diversity of species found in excreta (C. laurentii, C. albidus [currently Naganishia albida], C. liquefaciens [currently N. liquefaciens], C. friedmanii [currently N. friedmannii] and others) was higher than in tree hollows (C. laurentii, C. flavescens [currently Papiliotrema flavescens], and other yeasts). CONCLUSION: Many Cryptococcus species were isolated from excreta and tree hollows, and this fact is important for understanding the environmental epidemiology of those emerging pathogens for public health, as a way to implement surveillance actions and control of cryptococcosis.

Association of serum thyrotropin levels with coronary artery disease documented by quantitative coronary angiography: a transversal study.

OBJECTIVE: The association between coronary artery disease (CAD) and thyroid function remains controversial. We evaluated the thyroid function and graduated well-defined CAD as confirmed by quantitative coronary angiography (CA). SUBJECTS AND METHODS: We evaluated the serum TSH, free thyroxine, free triiodothyronine and thyroid antibody levels in 300 consecutive patients (age 61.6 ± 9.9 years and 54% were male) undergoing CAD diagnosis as confirmed by CA. Plaques with ≥ 50% stenosis being indicative of obstructive CAD, and patients were divided into groups according to main epicardial coronary arteries with plaques (0, 1, 2, 3). Lipid profiles and a homeostasis model assessment (HOMA-IR) were determined. RESULTS: Serum median (25% and 75% percentile) TSH levels in patients with group 2 and 3 (2.25; 1.66-3.12 mU/L and 4.99; 4.38-23.60 mU/L, respectively) had significantly higher TSH concentrations (p < 0.0001) than the group 0 (1.82; 1.35-2.51 mU/L). Furthermore, patients of group 3 had higher TSH concentration (p < 0.0001) than those of group 1 (1.60; 0.89-2.68 mU/L). Group 3 were older (64 ± 8.5 vs. 59 ± 9.5, p = 0.001), had more patients with dyslipidemia (84% versus 58%, p < 0.001), male (54% versus 44%, p = 0.01), hypertension (100% versus 86%, p < 0.001), and smoking (61% versus 33%, p < 0.001) than group 0. Multivariate stepwise logistic analysis showed TSH, age, HbA1c, and HOMA-IR were the CAD associated variables. CONCLUSIONS: In this cohort, elevated TSH levels in the high normal range or above are associated with the presence and severity of CAD besides may represent a weak CAD risk factor.

Effects of 24-h shift work in the emergency room on ambulatory blood pressure monitoring values of medical residents.

BACKGROUND: Medical residency is marked by long work hours and shift work. The acute effects of these factors on the blood pressure (BP) of medical residents have not been adequately evaluated. METHODS: A total of 61 medical residents underwent to ambulatory blood pressure monitoring (ABPM) during a 24-h shift work in the emergency room (ER) and during a common working day. RESULTS: Both mean 24-h systolic and diastolic BP (DBP) and mean diastolic BP readings during sleep were higher during the 24-h shift work in the ER than during common working day (117 v 113 mm Hg, P < .05; 73 v 69 mm Hg, P < .05; and 61 v 58 mm Hg, P < .05, respectively). Abnormally high mean BP readings were more frequent during the 24-h shift work in the ER than in common working day (19 v 8, P < .05). Pressure load, nocturnal BP fall and pulse pressure values were similar in these two different working situations. CONCLUSION: Working in the ER on a 24-h shift leads to abnormal BP behavior in medical residents, thus suggesting that this type of work may be a risk factor for cardiovascular disease.

[Serial electrophysiological studies of the heart's excito conductor system in patients with chronic chagasic cardiopathy]. / Estudos eletrofisiológicos seriados do sistema éxcito-condutor do coração de pacientes com cardiopatia chagásica crônica.

OBJECTIVES: To study the evolution of lesions in conduction system using invasive electrophysiological studies (EPS), the impact of these alterations on cardiovascular events (CVE), and the frequency of these events in chronic chagasic patients. METHODS: Prospective study, initiated in 1979 with clinical follow-up until 2000, with the participation of 28 chronic chagasic patients that were 18 to 65 years old, with bundle branch and/or atrioventricular blocks. The patients were submitted to two EPS with a minimum interval of four years between the studies in order to assess five electrophysiologists parameters that were correlated with CVE. A 24-hour Holter and echocardiogram were performed. RESULTS: The average follow-up time after the first EPS was 154.5 months while the interval between EPS was 107.5 months. Ages ranged from 25 to 65 years. Twenty seven patients presented complete right bundle branch block associated with a left anterior hemiblock. The echocardiogram showed alteration in twelve patients. During the 24-hour Holter and ventricular stimulation, only one patient presented sustained ventricular tachycardia (SVT). Nine presented CVE during the study and only the HV interval > or = 70 ms presented a significant statistical relationship with CVE. CONCLUSIONS: a) The chronic form of Chagas disease presents different progressive abnormality percentages for the electrophysiological variables and WP alterations are the most common. b) Among the electrophysiological findings, only the HV interval > or = 70 ms was associated with CVE. c) The incidence of CVE was 31.1% during the average follow-up period of 154.5 months.