Wearable Active Electrode for sEMG Monitoring Using Two-Channel Brass Dry Electrodes with Reduced Electronics.

Gel-based electrodes are employed to record sEMG signals for prolonged periods. These signals are used for the control of myoelectric prostheses, clinical analysis, or sports medicine. However, when the gel dries, the electrode-skin impedance increases considerably. Using dry active electrodes (AEs) to compensate variations of impedance is an alternative for long-term recording. This work describes the optimization of the electronic design of a conventional AE by removing the impedance coupling stage and two filters. The proposed work consisted of 5 stages: electrodes, amplification (X250), 2.2 Vdc offset, low-pass filter, and ADC with USART communication. The device did not need the use of electrolytic gel. The measurements of CMRR (96 dB), amplitude of the output sEMG signal (∼1.6 Vp-p), and system bandwidth (15-450 Hz) were performed in order to confirm the reliability of the device as an sEMG signal acquisition system. The SNR values from seven movements performed by eleven volunteers were compared in order to measure the repeatability of the measurements (average 30.32 dB for a wrist flexion). The SNR for wrist flexion measured with the proposed and the commercial system was compared; the values were 49 dB and 60 dB, respectively.

Prevalence of traffic rule infractions in Cali, Colombia, at sites where injury crashes occurred.

This study aim to determine the proportion of traffic rule infractions in Cali, Colombia, in places where a road traffic injury (RTI) occurred. Description of videotaping of sites where a person was injured in an RTI in 2009. Counts of road users and infractions were established for each road user group and were compared using a Z-test. They were found 13,491 users, distributed as follow: 8.9% were pedestrians, 4.6% cyclists, 24.6% motorcyclists, and 61.8% were automobile drivers. The most frequent traffic violation among motorcyclists was transiting on lines designated for other vehicles (55.2%). Among cyclists, the most frequent violations were transiting without a helmet (99.2%) and not wearing the designated vest (100%). Among pedestrians, crossing streets at prohibited places (77.3%), even at sites where a pedestrian bridge was present (72.7%), represented two common violations. Vulnerable road users committed more traffic infractions than automobile drivers (p < 0.001). High rates of traffic rule infractions among vulnerable road users were observed. Studies to better understand the occurrence of these behaviours and the promotion of effective interventions are warranted.

Experimental Verification of Modeled Thermal Distribution Produced by a Piston Source in Physiotherapy Ultrasound.

Objectives. To present a quantitative comparison of thermal patterns produced by the piston-in-a-baffle approach with those generated by a physiotherapy ultrasonic device and to show the dependency among thermal patterns and acoustic intensity distributions. Methods. The finite element (FE) method was used to model an ideal acoustic field and the produced thermal pattern to be compared with the experimental acoustic and temperature distributions produced by a real ultrasonic applicator. A thermal model using the measured acoustic profile as input is also presented for comparison. Temperature measurements were carried out with thermocouples inserted in muscle phantom. The insertion place of thermocouples was monitored with ultrasound imaging. Results. Modeled and measured thermal profiles were compared within the first 10 cm of depth. The ideal acoustic field did not adequately represent the measured field having different temperature profiles (errors 10% to 20%). Experimental field was concentrated near the transducer producing a region with higher temperatures, while the modeled ideal temperature was linearly distributed along the depth. The error was reduced to 7% when introducing the measured acoustic field as the input variable in the FE temperature modeling. Conclusions. Temperature distributions are strongly related to the acoustic field distributions.

Modeling the thermo-acoustic effects of thermal-dependent speed of sound and acoustic absorption of biological tissues during focused ultrasound hyperthermia.

PURPOSE: To evaluate the effects of thermal dependence of speed of sound (SOS) and acoustic absorption of biological tissues during noninvasive focused ultrasound (US) hyperthermia therapy. METHODS: A finite element (FE) model was used to simulate hyperthermia therapy in the liver by noninvasive focused US. The model consisted of an ultrasonic focused transducer radiating a four-layer biological medium composed of skin, fat, muscle, and liver. The acoustic field and temperature distribution along the layers were obtained after 15 s of hyperthermia therapy using the bio-heat equation. The model solution was found with and without the thermal dependence of SOS and acoustic absorption of biological tissues. RESULTS: The inclusion of the thermal dependence of the SOS generated an increment of 0.4 mm in the longitudinal focus axis of the acoustic field. Moreover, results indicate an increment of the hyperthermia area (zone with temperature above 43 °C), and a maximum temperature difference of almost 3.5 °C when the thermal dependence of absorption was taken into account. CONCLUSION: The increment of the achieved temperatures at the treatment zone indicated that the effects produced by the thermal dependence of SOS and absorption must be accounted for when planning hyperthermia treatment in order to avoid overheating undesired regions.

Prevalence of HLA-B*57:01 allele in Argentinean HIV-1 infected patients.

Hypersensitivity reaction to abacavir (ABC hypersensitivity syndrome, AHS) is strongly associated with the presence of the HLA-B*57:01 allele. This study was designed to estimate the prevalence of HLA-B*57:01 allele in Argentinean HIV-1 infected patients. We analyzed the presence of HLA-B*57:01 allele in 1646 HIV-1 infected patients from different regions of Argentina. This allele was detected in 81 patients; most of them corresponded to patients living in the central region of the country. The prevalence of HLA-B*57:01 was 4.9%, similar to other Caucasian populations and higher than other data reported for South American populations. This strongly supports screening for the presence of HLA-B*57:01 in abacavir treatment of HIV-1 in our country.

Limb amputation among patients with surgically treated popliteal arterial injury: analysis of 15 years of experience in an urban trauma center in Cali, Colombia.

BACKGROUND: Popliteal arterial injuries carry a high risk of amputation. The currently available literature from both civilian and military experiences is characterized by a wide variation of recommendations for surgical management. We questioned how these recommendations have been applied in our practice. Therefore, we aimed to identify predictors of amputation after popliteal arterial injury. METHODS: We conducted an observational study of 175 patients with popliteal arterial injuries who underwent surgical treatment from 1992 to 2006 at a level I trauma center in Cali, Colombia. Information on demographic characteristics, clinical information, and surgical management was collected from clinical records. The outcome measure was amputation within 30 days following the first surgical intervention. RESULTS: The amputation rate was 17.1%. A multivariable logistic regression model indicates that blunt mechanism (odds ratio [OR] 4.79, 95% confidence interval [CI] 1.49-15.42), signs of ischemia (OR 5.29, 95% CI 1.48-18.91), ligation of the popliteal vein of the compromised limb during surgical exploration (OR 3.83, 95% CI 1.20-12.18), and the development of arterial thrombosis (OR 56.51, 95% CI 12.36-258) were found to be independent predictors of amputation. Fractures, popliteal venous injuries, prolonged time between injury and surgery, fasciotomies, and graft arterial repair were not statistically significant predictors of amputation. CONCLUSIONS: Emphasis on the early assessment and prompt identification of signs of ischemia after popliteal arterial injury continue to be the most important factor for reducing the risk of amputation, especially in blunt trauma. Vascular trauma teams must emphasize the need for the specialized management of popliteal veins. Clinical research is needed in order to identify means of decreasing arterial thrombosis after popliteal repair.

Therapy ultrasound equipment characterization: Comparison of three techniques.

Methods for characterizing ultrasonic therapy equipment rapidly and easily have to be implemented in order to avoid damages to patients; the existent methods measure different parameters in the ultrasonic beam that can be used to determine if the equipment works appropriately. In this paper, a comparison of three methods to characterize the ultrasonic beam is presented. The first one is a C-scan with microprobe which uses a hydrophone for measuring the signal and a positioning system. The second method is the IR-thermography which uses a phantom to absorb the ultrasonic energy and to convert it into heat. Here, the heat distribution is obtained with an IR camera. The third method uses a sheet of thermochromic liquid crystals (TLC) as sensor and a phantom to absorb the energy. The heat distribution is obtained with a normal camera because the TLCs change their color as a function of temperature. The results indicate that each technique has its own benefits, but the most important parameters can be obtained with only one of them.

Association of Burkitt's lymphoma with the Epstein-Barr virus in two developing countries.

The clinical presentation of Burkitt's lymphoma (BL) and it's association with the Epstein-Barr virus (EBV) varies in different geographic areas, BL in developing countries being "intermediate" between the sporadic and endemic types, both in it's clinical presentation and it's association with EBV, which varies from 25-80%. In this study we have analysed the clinical features, EBV association, subtype and prevalence of the deleted variant of the Latent Membrane Protein-1 (LMP-1) of EBV in forty-two cases from two developing countries- India (n = 25) and Argentina (n = 17). In both countries the abdomen was the site most commonly involved while jaw involvement was rare. EBV was detected by in-situ hybridization using the EBER-1 RNA probe. 47% of cases from Argentina and 80% of cases from India were EBER positive. EBV typing using EBNA-3C primers showed a predominance of Type A in both countries (India-13/16 and Argentina-(7/8)). The 30bp deletion of the LMP-1 gene was detected in all evaluated cases from Argentina while the wild type of the gene was seen in all the evaluable Indian cases. Our study highlights the similarities and differences in the clinical presentation and EBV association of BL in two developing countries and also indicates that the subtype of EBV and prevalence of the LMP-1 deletion may reflect the predominant subtype in a particular population.

[Allergic rhinitis. Current symptoms]. / Rinitis alérgica. Síntomas actuales.

BACKGROUND: Whatever disease whose etiology is determined by environment should have a periodic check-up for etiologic agents especially for the group of symptoms that accompanies it's clinical features. The purpose of this research is to check if the classic symptomatology described in Allergic Rhinitis (AR) corresponds to the pre: reality or need some modifications in it's diagnostic interpretation. MATERIAL AND METHOD: For this we evaluated in a period of ninety days 438 patients. RESULTS: Both children and adults 58.22% females and 41.78% males aged between seven months and 67 years), who have AR. The highest level of occurrence by was between 5 and 9 years (23.5%. Symptomatology rhinorrea 91.32%, nasal congestion 87.89%, continuous sneezing 84.93%, nasal itching 81.27%, epistaxis 23.74% and nasal. Dryness 22.15%. CONCLUSION: We have found in AR that the vasomotor phenomena and anatomic-vascular lesions are increasing in the affected people who are born in Mexico City and those who have resided for at least five years in Mexico City and it's vicinity.

Parenting and physical punishment: primary care interventions in Latin America.

Physical punishment is a form of intrafamilial violence associated with short- and long-term adverse mental health outcomes. Despite these possible consequences, it is among the most common forms of violent interpersonal behavior. For many children it begins within the first year of life. The goal of this study was to determine the feasibility of involving public sector primary health care providers to inform parents about alternatives to physical punishment. The study used a qualitative design utilizing focus groups and survey questionnaires with parents and providers at six clinic sites chosen to be representative of public sector practice settings in Costa Rica and in metropolitan Santiago, Chile. The data were collected during 1998 and 1999. In the focus groups and surveys the parents voiced a range of opinions about physical punishment. Most acknowledged its common use but listed it among their least preferred means of discipline. Frequency of its use correlated positively with the parents' belief in its effectiveness and inversely with their satisfaction with their children's behavior. Some parents wanted to learn more about discipline; others wanted help with life stresses they felt led them to use physical punishment. Parents reported they chose other family members more frequently as a source of parenting information than they did health care providers. Some parents saw providers as too rushed and not knowledgeable enough to give good advice. Providers, in turn, felt ill equipped to handle parents' questions, but many of the health professionals expressed interest in more training. Parents and providers agreed that problems of time, space, and resources were barriers to talking about child discipline in the clinics. Many parents and providers would welcome a primary-care-based program on physical punishment. Such a program would need to be customized to accommodate local differences in parent and provider attitudes and in clinic organization. Health care professionals need more training in child discipline and in the skills required to interact with parents on issues relating to child behavior.

[Incidence of allergic diseases and atopic markers in a tertiary hospital]. / Incidencia de enfermedades alérgicas y marcadores atópicos en un hospital de tercer nivel.

With the aim to know both the distribution and features of allergic disorders in a third level hospital at Mexico city we performed a descriptive study throughout one year, patients data were obtained from their clinical records at initial evaluation. We attended 1486 patients, 744 females (50.1%) and 742 males (49.9%). Children under 10 years-old were the main ages group (46.8%). Forty-four percent of the patients had at least one atopic relative, one brother or sister in 19.5%. White blood cells results showed peripheral cosinophilia in 57.6% patients and nasal cosinophilia in 58.1%. We found S. aureus, coagulase positive in 55% of 192 positive throat cultures. The more frequent diagnoses were rhinitis and asthma (46.3%), rhinitis (20.7%) and asthma (14.1%). We consider that the more prominent findings were the high index of S. aureus, higher atopic family history in brothers and the association between cosinophilia and allergic disorders.

[Comparison of extracts of cockroaches, house dust and Dermatophagoides with intradermal tests in allergy patients]. / Comparación entre extractos de cucaracha, polvo casero y Dermatophagoides con pruebas intradérmicas en pacientes alérgicos.

In the order to know both the sensitivity and positivity between the allergenic extracts of cockroach (C), house dust (HDJ, and Dermatophagoides pteronyssinus (Dpt) we made a transversal study in 783 allergic patients who underwent intradermal skin tests with the antigens of C, HD and Dpt. Allergic asthma and rhinitis were the more frequent diagnosis. There was no significative difference between the sensitivity to C and HD (p = 0.1),-women were more sensitive to C than to HD (p < 0.05). We found a greater sensitivity to Dpt than C and HD (p < 001). There were more positive patients to C than to HD (p = 0.01) and although we observed more positive patients to Dpt than to C (p = 0.01) this difference was not significative for women (p = 0.05). We can conclude than cockroach, as an allergic source, has similar importance that house dust mite, and it is inadequate its substitution with house dust extracts in skin tests screening.

N-myc oncogene and urinary catecholamines in children with neuroblastoma.

This paper reports the analysis of N-myc amplification, urinary vanillylmandelic acid (VMA), and norepinephrine (NE) excretion and survival in 22 children with neuroblastoma and 7 with ganglio-neuroblastoma. Five patients had N-myc amplification (from 30 to more than 200 copies), all of whom had advanced-stage disease. The urinary excretion of VMA was normal in all of them, only one showed increased NE excretion. All patients with stage C-D disease and one copy of N-myc had increased VMA urinary excretion and increased (9/14) or normal (5/14) NE urinary excretion. All patients with stage A or B disease had one copy of N-myc. Half of them showed increased VMA urinary levels, while only 3/10 showed increased NE urinary values. Comparison of cumulative survival curves in relation to N-myc amplification and to VMA and NE urinary excretion showed a clear parallelism. Amplification of N-myc corresponded to normal VMA and NE urinary excretion, and was associated with the worst prognosis (P < 0.01), while increased VMA and/or NE excretion was found in patients with only one copy of N-myc.

Epstein-Barr virus genotypes in AIDS-associated lymphomas are similar to those in endemic Burkitt's lymphomas.

PCR was used to screen EBV-positive lymphomas from endemic and sporadic Burkitt's lymphoma patients, including EBV-positive lymphomas derived from patients with HIV infection. Only 10% of sporadic lymphomas from either North America (1/15) or South America (2/14) were associated with the type 2 EBV strain, whereas 50% (8/16) of lymphomas from equatorial Africa and 46% (10/22) of HIV-associated lymphomas were positive for the type 2 strain. These data, in conjunction with previous reports, suggest that the proportions of strain types in Burkitt's lymphoma reflect the proportions of strain types in peripheral lymphocytes, and not simply the prevailing regional strain. The increased association of the type 2 strain in lymphocytes and lymphomas from HIV-infected individuals and from Africa may be a result of intermittent (malaria) or continuous (HIU) compromise of immune function in these populations.

The pattern of p53 mutations in Burkitt's lymphoma differs from that of solid tumors.

Available evidence suggests that, among hematological malignancies, p53 is most often mutated in Burkitt's lymphoma (BL). However, much of the published data is based on cell lines. We have, therefore, analyzed BL biopsies to determine more accurately the frequency and pattern of p53 mutations in primary tumors and to determine whether there are differences among the various subtypes of BL. Among 27 BL biopsies from South Africa, we have observed mutations in the p53 gene (exons 5 through 8) in 37% of tumors. The higher frequency of mutations in cell lines (70%) suggests that mutation of p53 may be associated with tumor progression. Summarizing available data we conclude that the presence of mutated p53 in BL is independent of the geographic origin of the tumor, the 8;14 chromosomal breakpoint locations and Epstein-Barr virus association. We also find that the mutational spectrum of p53 in BL differs from that observed in nonlymphoid tumors. More than 50% of mutations in BL are clustered in a small stretch of 33 amino acids (codons 213 to 248). Interestingly, codon 213 appears to be as frequently mutated as codon 248. Conversely, codon 273, often mutated in solid tumors, is rarely involved in BL.

Molecular epidemiology of Burkitt's lymphoma from South America: differences in breakpoint location and Epstein-Barr virus association from tumors in other world regions.

We have previously shown that the endemic (African) and sporadic (North American) forms of Burkitt's lymphoma (BL) differ at a molecular level. We have now extended our studies to the molecular epidemiology of BL in South America, specifically to two climatic regions: temperate (Argentina and Chile) and tropical (Brazil). We have examined the patterns of chromosomal breakpoint locations in 39 tumors with respect to geography and Epstein-Barr virus (EBV) association. The result of these analyses provide further support for the existence of pathogenetically distinct subtypes of BL in different world regions. The majority of breakpoints on chromosome 8 in South American BL (41%) occurred in the immediate flanking region of c-myc, ie, further 5' of the "typical" sporadic breakpoints, in the first exon/intron region, and further 3' of the "typical" endemic breakpoints, which are usually distant from c-myc. However, the distribution of breakpoints on chromosome 14 in tumors from the temperate and tropical regions of South America is similar to that observed in sporadic and endemic tumors. Interestingly, only one tumor with an unrearranged c-myc gene joined to the S mu region of chromosome 14 was observed. This combination was also rarely observed in our earlier series and presumably is either less readily generated by the mechanism that mediates 8;14 translocation or requires other, infrequent genetic changes to provide the necessary selective advantage for lymphomagenesis. The frequency of EBV association in South American BL (51%) is also intermediate with respect to tumors from the United States (30%) and Africa (100%). No correlation with the breakpoint location on chromosome 8 was discernable. Surprisingly, only 54% of tumors with breakpoint outside c-myc were EBV positive. This is in contrast to endemic tumors and suggests that any pathogenetic contribution of EBV is not dependent on breakpoint location, but is more likely to complement additional pathogenetic elements that differ in different world regions.

[Molecular analysis in Argentinian patients with Burkitt's lymphoma]. / Análisis molecular en pacientes argentinos con linfoma de Burkitt.

Burkitt's lymphoma (BL) is a B-cell neoplasm that occurs in children throughout the world. Two distinct entities of this disease have been recognized: endemic BL (eBL), described in equatorial Africa, and sporadic BL (sBL), described in the USA and Europe. There are striking differences in the incidence, epidemiology, clinical presentation and molecular characteristics of the tumour cells between the two forms, although all BL carry identical specific chromosomal translocations. We have examined the position of the chromosomal breakpoints in the t (8;14) translocation, characteristic of this tumour, relative to the c-myc oncogene in chromosome 8, and the immunoglobulin heavy chain (IGH) locus in chromosome 14 in samples obtained from four Argentine patients using the Southern blot technique. DNA from the tumours was digested with specific enzymes and hybridized with DNA probes from the c-myc (first and third exons) and IGH locus (C mu, S mu and JH). Our analysis shows that all tumours carried the t (8;14) as shown by clonal rearrangements of c-myc in DNA treated with the enzymes Hind III and Eco RI. Moreover, all 4 tumours had chromosome 8 breakpoints within the Hind III restriction fragment that spans the gene. In case 1 it was between the Hind III and Pst I sites 5' to the first exon, in cases 2 and 4 between the Pvu II and Sma I sites 5' to the first exon and in case 3 within the first exon (Sma I-Pvu II segment).(ABSTRACT TRUNCATED AT 250 WORDS)