Estimación en la Intención de Agarres: Cilíndrico, Esférico y Gancho Utilizando Redes Neuronales Profundas / Estimation of Hand-Grip Intention: Cylindrical, Spherical and Hook Using Deep Neural Networks

Resumen Las amputaciones de extremidades superiores pueden producir diversos grados de incapacidad en la persona afectada, esto es exacerbado aún más, si se presenta durante un periodo de su vida laboral activa, por esta razón es de importancia social el estudio de las prótesis y algoritmos que ayuden a un mejor control de estas por parte del usuario. En esta investigación, se propone una arquitectura basada en redes neuronales recurrentes del tipo Long Short-Term Memory y redes convolucionales para la clasificación de señales electromiográficas, con aplicaciones para control de prótesis de mano. La red propuesta clasifica tres tipos de agarres realizados con la mano: cilíndrico, esférico y de gancho. El modelo propuesto al ser evaluado mostró una eficiencia (accuracy) del 89 %, en contraste con una red neuronal artificial basada en capas completamente conectadas que solo obtuvo una eficiencia del 80% en la predicción de los agarres. El presente trabajo se limita solamente a evaluar la red ante una entrada de electromiograma y no se implementó un sistema de control para la prótesis de la mano. Así, una arquitectura de redes convolucionales para el control de prótesis de mano que pueden ser entrenadas con las señales del sujeto.

Abstract Upper extremities amputations can produce different disability degrees in the amputated person, this is acerbated even more, when it happens during active working life. So, for this reason, it is of social importance the study of prostheses and algorithms that help a better control of these by the user. In this research, we propose an architecture based on recurrent neural networks, called Long Short-Term Memory, and convolutional neural networks for classification of electromyographic signals, with applications for hand prosthesis control. The proposed network classifies three types of movements made by the hand: cylindrical, spherical and hook grips. The proposed model showed an efficiency (accuracy) of 89%, in contrast to an artificial neural network based on completely connected layers that only obtained an efficiency of 80% in the prediction of the hand movements. The present work is limited to evaluate the network with an electromyogram input, the control system for hand prosthesis was not implemented. Thus, an architecture of convolutional networks for the control of hand prostheses that can be trained with the signals of the subject.

Whole-genome sequencing suggests a chemokine gene cluster that modifies age at onset in familial Alzheimer's disease.

We have sequenced the complete genomes of 72 individuals affected with early-onset familial Alzheimer's disease caused by an autosomal dominant, highly penetrant mutation in the presenilin-1 (PSEN1) gene, and performed genome-wide association testing to identify variants that modify age at onset (AAO) of Alzheimer's disease. Our analysis identified a haplotype of single-nucleotide polymorphisms (SNPs) on chromosome 17 within a chemokine gene cluster associated with delayed onset of mild-cognitive impairment and dementia. Individuals carrying this haplotype had a mean AAO of mild-cognitive impairment at 51.0 ± 5.2 years compared with 41.1 ± 7.4 years for those without these SNPs. This haplotype thus appears to modify Alzheimer's AAO, conferring a large (~10 years) protective effect. The associated locus harbors several chemokines including eotaxin-1 encoded by CCL11, and the haplotype includes a missense polymorphism in this gene. Validating this association, we found plasma eotaxin-1 levels were correlated with disease AAO in an independent cohort from the University of California San Francisco Memory and Aging Center. In this second cohort, the associated haplotype disrupted the typical age-associated increase of eotaxin-1 levels, suggesting a complex regulatory role for this haplotype in the general population. Altogether, these results suggest eotaxin-1 as a novel modifier of Alzheimer's disease AAO and open potential avenues for therapy.

[Improvements in lung preservation: 3 years' experience with a low-potassium dextran solution]. / Mejoras en la preservación pulmonar. Tres años de experiencia con una solución de dextrano bajo en potasio.

OBJECTIVE: Lung preservation quality is a crucial factor in the success of a lung transplant. In October 2000 we stopped using Euro-Collins (EC) lung preservation solution and began using a low potassium dextran solution (Perfadex [PER]). The objective of the present study was to assess outcome with the 2 solutions. MATERIAL AND METHODS: We analyzed the results of 68 lung transplants in which PER was used and compared the results with those of a historical control group consisting of the same number of transplants in which EC was used. RESULTS: There were no significant differences in the ages and diagnoses of the recipients in the 2 groups. Waiting list time was longer in the PER group. The most frequent cause of donor death in the EC group was craniocerebral trauma (62%), whereas in the PER group it was cerebral hemorrhage (54%). In the PER group more double lung transplants were performed than in the EC group (78% and 53% respectively; P=.002). There were no differences in the use of extracorporal circulation or ischemia time between the 2 groups. Early graft function, based on the patient's oxygenation index (ratio of PaO2 to inspired oxygen fraction [FiO2]) on arrival at the intensive care unit, was similar in the 2 groups. The incidence of severe graft failure (PaO2/FiO2<150 mm Hg) was significantly lower in the PER group than in the EC group (16% and 37% respectively; P=.01). No significant differences in hours of mechanical ventilation or postoperative mortality between the 2 patient series were found. CONCLUSIONS: Use of the newer lung preservation solution --PER-- led to a 50% lower incidence of severe ischemia-reperfusion graft injury during the early recovery from lung transplantation.

Mejoras en la preservación pulmonar. Tres años de experiencia con una solución de dextrano bajo en potasio / Improvements in lung preservation: 3 years' experience with a low-potassium dextran solution

OBJETIVO: La calidad de la preservación pulmonar es uno de los aspectos más determinantes en el éxito del trasplante pulmonar. En octubre del año 2000 modificamos nuestra solución de preservación pulmonar, que hasta entonces era el Euro-Collins (EC), y comenzamos a utilizar una solución de dextrano bajo en potasio, comercializada como Perfadex (PER). El objetivo de este estudio es analizar los resultados de ambos métodos. MATERIAL Y MÉTODOS: Hemos analizado los resultados de 68 trasplantes pulmonares con PER y los hemos comparado con los de una serie retrospectiva del mismo número de trasplantes realizados con EC. RESULTADOS: No existen diferencias significativas respecto a la edad o el diagnóstico de los receptores entre ambos grupos. El tiempo en lista de espera fue mayor en el grupo de PER. La causa de muerte del donante más frecuente del grupo EC fue el traumatismo craneoencefálico (62%), mientras que en el grupo de PER fue la hemorragia cerebral (54%). En el grupo de PER se realizaron más trasplantes bipulmonares que en el de EC (el 78 y el 53%, respectivamente; p = 0,002). No hay diferencias en la indicación de circulación extracorpórea o tiempos de isquemia entre ambos grupos. Se evaluó la función pulmonar temprana a través del índice de oxigenación (PaO2/FiO2) a la llegada a la unidad de cuidados intensivos, que fue comparable entre ambos grupos. La incidencia de disfunción grave del injerto (PaO2/FiO2 < 150 mmHg) fue significativamente inferior en el grupo de PER frente al de EC (el 16 y el 37%, respectivamente; p = 0,01). No encontramos diferencias significativas respecto a las horas de ventilación mecánica ni en cuanto a la mortalidad postoperatoria entre las 2 series. CONCLUSIONES: Con la aplicación clínica de esta nueva solución de preservación pulmonar se obtiene una reducción del 50% en la incidencia de la lesión de isquemia-reperfusión grave del injerto en el postoperatorio inmediato del trasplante pulmonar

OBJECTIVE: Lung preservation quality is a crucial factor in the success of a lung transplant. In October 2000 we stopped using Euro-Collins (EC) lung preservation solution and began using a low potassium dextran solution (Perfadex [PER]). The objective of the present study was to assess outcome with the 2 solutions. MATERIAL AND METHODS: We analyzed the results of 68 lung transplants in which PER was used and compared the results with those of a historical control group consisting of the same number of transplants in which EC was used. RESULTS: There were no significant differences in the ages and diagnoses of the recipients in the 2 groups. Waiting list time was longer in the PER group. The most frequent cause of donor death in the EC group was craniocerebral trauma (62%), whereas in the PER group it was cerebral hemorrhage (54%). In the PER group more double lung transplants were performed than in the EC group (78% and 53% respectively; P=.002). There were no differences in the use of extracorporal circulation or ischemia time between the 2 groups. Early graft function, based on the patient’s oxygenation index (ratio of PaO2 to inspired oxygen fraction [FiO2]) on arrival at the intensive care unit, was similar in the 2 groups. The incidence of severe graft failure (PaO2/FiO2<150 mm Hg) was significantly lower in the PER group than in the EC group (16% and 37% respectively; P=.01). No significant differences in hours of mechanical ventilation or postoperative mortality between the 2 patient series were found. CONCLUSIONS: Use of the newer lung preservation solution —PER— led to a 50% lower incidence of severe ischemiareperfusion graft injury during the early recovery from lung transplantation

Widow and widower remarriage: an analysis in a rural 19th century Costa Rican population and a cross-cultural discussion.

Although the topic of remarriage features saliently in the cultural anthropological literature, it is virtually absent in the biological anthropology journals. This is perplexing, given that remarriage affects the differential reproductive success of males and females in a community, and could well impact a community's population structure. In this paper, we research remarriage practices in a rural 19th century community in Costa Rica. Although we find support for the proposition that males are more likely to remarry than females, we find that widows who remarry are not all young and able to reproduce. Our findings support the cross-culturally-generated suggestion that a female's ability not to remarry is tied to her to ability to own property. Remarriage is a topic of interest to biological anthropologists from a cross-cultural and biocultural perspective.

Epidemic cycles in agricultural populations: a cross-cultural study.

A cross-cultural analysis of mortality patterns is of interest to biological anthropologists and genetic epidemiologists. In this paper, we examine four agricultural populations from Costa Rica, Hungary, and the United States in order to determine if they suffered from a cyclical distribution of epidemics. When possible, we look at the mortality time series of adults and children separately. Of the 2 series, only 2 show significant epidemic cycles. Both are in the Hungarian groups and both affect subadults. Otherwise, the Costa Rica, U.S., and adult series of the Hungarian groups do not show any periodicity of mortality peaks. Our results indicate that epidemic cycles are not as ubiquitous in small agricultural groups as the literature would suggest.

Isodicentric Y chromosomes and secondary microchromosomes.

We report here on two mosaic patients with both an idic(Yp) and a microchromosome. FISH with the DYZ3 alphoid repeat demonstrated that the isodicentrics effectively exhibited two alphoid clusters whereas the small markers had a Y-centromere. These data, along with 4 previous observations, indicate that such microchromosomes effectively result from functional dicentricity of isodicentric Y-chromosomes and represent the excision of one centromere plus various amounts of adjacent chromatin. Other than a real infrequency of such a concurrence or a very low proportion of the cell line(s) containing the microchromosome, the paucity of observations points to a high rate of underdiagnosis as revealed by two idic(Y) instances in which the microchromosome was detected only in samples assessed by FISH.

Frequency of twinning in two Costa Rican ethnic groups: an update.

Variation in the frequency of twinning among human populations has been presumed to reflect genetic differences. It has been commonly reported that populations of African ancestry have the highest, those of Asian ancestry the lowest, and those of European and Middle-Eastern ancestry intermediate frequencies of twinning. Populations from the Americas have been reported to have intermediate twinning frequencies, presumably reflecting their admixture. In this context, Madrigal (1994. Am J Hum Biol 6:215-218) reported virtually identical (and high) twinning frequencies in two Costa Rican ethnic groups, one of African, the other of Euro-Amerindian ancestry. These frequencies were interpreted in light of frequent inter-ethnic unions, and it was predicted that the two groups would not differ substantially in gene frequencies of several blood enzyme systems. This paper reports the gene frequencies of both groups for such systems. The samples differ significantly for systems that have clearly different frequencies in African and European populations. Given that the groups are actually different in gene frequencies and not homogenous as predicted earlier, the conclusion that twinning frequencies are similar as a result of a similar genetic make up can be questioned. The results challenge the assumption that if populations have similar twinning frequencies it is because they are genetically similar and argue for a stronger environmental component for twinning frequencies.

Presenilin-1-associated abnormalities in regional cerebral perfusion.

OBJECTIVE: To investigate the influence of the presenilin-1 gene (PS-1) mutation on regional cerebral perfusion, SPECT was evaluated in 57 individuals. The subjects were members of a large pedigree from Colombia, South America, many of whom carry a PS-1 mutation for early-onset AD. METHODS: Members of this large kindred who were cognitively normal and did not carry the PS-1 mutation (n = 23) were compared with subjects who were carriers of the mutation but were asymptomatic (n = 18) and with individuals with the mutation and a clinical diagnosis of AD (n = 16). Cerebral perfusion was measured in each subject using hexamethylpropyleneamine oxime SPECT. The data were analyzed in two ways: 1) Mean cerebral perfusion in each of 4320 voxels in the brain was compared among the groups using t-tests (t-maps); and 2) each individual received a weighted score on 20 vectors (factors), based on a large normative sample (n = 200), using a method known as singular value decomposition (SVD). RESULTS: Based on t-maps, subjects with the PS-1 mutation who were asymptomatic demonstrated reduced perfusion in comparison with the normal control subjects in the hippocampal complex, anterior and posterior cingulate, posterior parietal lobe, and anterior frontal lobe. The AD patients demonstrated decreased perfusion in the posterior parietal and superior frontal cortex in comparison with the normal control subjects. Discriminant function analysis of the vector scores derived from SVD (adjusted for age and gender) accurately discriminated 86% of the subjects in the three groups (p < 0.0005). CONCLUSION: Regional cerebral perfusion abnormalities based on SPECT are detectable before development of the clinical symptoms of AD in carriers of the PS-1 mutation.

Acute thrombosis of the renal transplant artery after a single dose of OKT3.

We present the case of an 18-year-old male who 8 months after a living-related donor, one-haplotype-matched renal transplantation developed acute thrombosis of the renal allograft artery, within 10 h of the first dose of OKT3. The antibody therapy had followed five daily doses of intravenous pulse methylprednisolone for a Banff class 1B acute tubulointerstitial rejection, on a ciclosporin-based immunosuppression protocol. We briefly review the literature on the incidence of vascular thrombosis after transplantation and the procoagulant effects of OKT3, pulse methylprednisolone, and ciclosporin therapy.

Ethnicity, gene flow, and population subdivision in Limón, Costa Rica.

In this paper we examine the effects of ethnicity on the gene flow between two groups living in Limón, Costa Rica. Our main interest is to determine if ethnicity has acted as a barrier to the exchange of genes, and if the groups have remained distinct genetically. We report the admixture estimates, F(st) values, and inbreeding coefficients of the two samples. The data consist of blood samples and surnames obtained from 375 individuals. The subjects' two surnames were analyzed to determine the ethnicity of their parents (individuals carry their father's and mother's first surnames). We used the formula of Crow and Mange ([1965] Eugen Q 12:199-203) to compute F(t), F(n), and F(r) with the surnames. Admixture estimates were computed for both groups using the computer program ADMIX.PAS kindly provided by Jeffrey Long. The estimates for the Hispanic-Limonense group are M1 = 0.5866 European, M2 = 0.3383 Amerindian, and M3 = 0.0751 African ancestry. For the Afro-Limonense group, the admixture estimates indicate M1 = 0.1047 European, M2 = 0.1357 Amerindian, and M3 = 0.7595 African ancestry. The F(st) values are F(st) = 0.00558 for the Hispanic group and F(st) = 0.05137 for the Afro-Limonense group. These F(st) values indicate that the Afro-Limonense group has experienced more genetic drift than has the other group, possibly as a result of its long history of isolation in Costa Rica. Indeed, when plotted along a scaled eigenvector R matrix of Caribbean gene frequencies, the two Limonense groups did not cluster with each other. Thus we conclude that the two ethnic groups have remained distinct breeding populations.

[Factorial and discriminant analyses of neuropsychological variables in familial and sporadic late onset Alzheimer disease]. / Anàlisis factorial y discriminante de variables neuropsicológicas en la demencia tipo Alzheimer de inicio tardío, familiar y esporádica.

INTRODUCTION: Prevalence of late onset Alzheimer's disease (LOAD) both familial and sporadic is increasing with the raising proportion of third-age population. There are evidences either supporting or rejecting the existence of differences in the behavior of neuropsychological variables between familial and sporadic cases of LOAD. OBJECTIVE: To identify neuropsychological variables discriminating between familial and sporadic cases of LOAD, in order to detect clinical manifestations that may provide information on the pathological process of the neurodegenerative process. PATIENTS AND METHODS: Using sequential sampling, we selected individuals affected by LOAD according to the criteria of the DSM-IV and NINCS-ADRDA. The following neuropsychological protocol was used: CERAD, Wisconsin, Phonological Fluency, Rey's Figure, Raven, A Cancellation Test, WAIS (Arithmetic); also used were: Global Deterioration Scale, Functional Assessment Staging of Reisberg (FAST), Barthel and Yesavage. Parametrical and non-parametrical univariate, factorial (principal components) and discriminant analyses were performed. In total, 52 patients were analyzed (average age: 74.8 years; mean age at onset of the disease: 69 years; time of disease's evolution: 5.7 years; average of educational level: 6.4 years). RESULTS: No significant statistical differences were found in clinical or neuropsychological variables between familial and sporadic cases of LOAD. Additionally, neither variables nor models were detected discriminating significantly between them. CONCLUSION: Familial and sporadic cases of LOAD present the same clinical and neuropsychological phenotype which makes very probable that sporadic cases are low penetrance familial ones.

Análisis factorial y discriminante de variables neuropsicológicas en la demencia tipo Alzheimer de inicio tardío, familiar y esporádica / Factorial and discriminant analyses of neuropsychological variables in familial and sporadic late onset Alzheimer disease

Introducción. La prevalencia de demencia tipo Alzheimer de inicio tardío (DTAIT) va en aumento, dado el mayor porcentaje de población de la tercera edad. Existen evidencias a favor y en contra de que el comportamiento de las variables neuropsicológicas es diferente entre los casos familiares y los esporádicos de DTAIT. Objetivo. Identificar variables neuropsicológicas que discriminen entre DTAIT familiar y esporádica, con el fin de detectar manifestaciones clínicas particulares que informen sobre el proceso fisiopatológico del síndrome. Pacientes y métodos. Mediante muestreo secuencial se seleccionaron individuos con DTAIT según los criterios del DSM-IV y NINCS-ADRDA. Se utilizó el siguiente protocolo neuropsicológico: CERAD, Wisconsin, fluidez fonológica, figura de Rey, Raven, cancelación de la A, WAIS (prueba aritmética); además, se emplearon: la escala de deterioro global, la escala funcional de Reisberg, el índice de Barthel y Yesavage. Se realizaron los siguientes análisis: univariado mediante pruebas paramétricas y no paramétricas; factorial mediante estudio de componentes principales, y discriminante. Se estudiaron 52 pacientes cuya edad promedio al inicio de la demencia era de 69 años, con una media de 74,8 años en el momento de la evaluación, 5,7 años como media de evolución de la enfermedad y una escolaridad media de 6,4 años. Resultados. No se encontraron diferencias estadísticas significativas, clínicas y neuropsicológicas, entre ambos grupos, ni variables o modelos que discriminaran significativamente entre uno y otro. Conclusión. Las DTAIT familiar y esporádica presentaron en la población investigada el mismo fenotipo clínico y neuropsicológico, lo que hace muy probable que los casos esporádicos sean casos familiares con baja penetrancia (AU)

Neuropsychological profile of a large kindred with familial Alzheimer's disease caused by the E280A single presenilin-1 mutation.

It was hypothesized that subjective memory complaints represent the earliest sign of dementia in carriers of the presenilin-1 (PS1) mutation. A total of 122 subjects (44 males, 78 females) were included in this study. Forty of them were positive for the mutation in the PS1 gene (mutation positive, MP) whereas 82 showed negative results (mutation negative, MN). Subjects were active, functionally normal, even though some of them complained of memory difficulties. Two groups of neuropsychological instruments were administered: (a) The Consortium to Establish a Registry for Alzheimer's Disease (CERAD) neuropsychological test battery (Morris et al., 1989), and (b) some additional neuropsychological tests (Raven Test, Wechsler Memory Scale, Rey-Osterrieth Complex Figure, Boston Naming Test, Naming of Categories, Boston Diagnostic Aphasia Examination, Memory of Three Phrases, Knopman Test, Digit Symbol, and Visual "A" Cancellation Test). Performance in both groups was quite similar. In a secondary analysis, the MP group was subdivided into two subgroups: without and with memory complaints. When comparing both subgroups, a better performance in the first subgroup was found throughout the different subtests. Statistically significant differences were observed in the following test scores: Mini-Mental State Examination, Naming Test (Low Frequency), Memory of Words Test, Recall of Drawings, Wechsler Memory Scale (Logical Memory, Associative Learning, and Total Score), Rey-Osterrieth Complex Figure (Immediate Recall Condition), Boston Diagnostic Aphasia Examination (Complex Ideational Material Subtest), Memory of Three Phrases Test, Serial Verbal Learning (maximum score and Delayed Recall), Knopman Test (First Trial, Second Trial, and Recall after 5 Minutes), Digit Symbol, and Visual "A" Cancellation Test (Additions). Results supported the hypothesis that memory complaints represent the earliest symptom of familial Alzheimer's disease. In addition to the memory difficulties, other minor cognitive impairments were also found, particularly, mild anomia, concentration difficulties and defects in the understanding of complex verbal material.

Mating pattern and population structure in Escazú, Costa Rica: a study using marriage records.

A primary focus of historical demographic research is to understand how a population's mating pattern can affect its genetic structure. By using surnames, researchers can reconstruct gene flow into a population as well as within it: the population structure. Indeed, Lasker (1988a) noted that the distribution of surnames reflects the effect of mate choice on a population's genetic structure. Here, we study the mating pattern of a small, clearly established breeding population in Costa Rica (Escazú) during 1800-1839 and 1850-1899. We found that a large proportion of marriages involved individuals who were members of long-standing or core families. Indeed, 27 families provided 56% of all consorts throughout the period under study. When new surnames appeared in the records (presumably as a result of immigration), they were introduced more frequently by males, indicating that more males than females migrated into the community. The core families did not mate preferentially among themselves but appear to have readily accepted the migrants. Indeed,the greatest preponderance of repeated-surname marriages was that expected by chance. However, nonrandom surname repetition is evident when marriages between nonillegitimate consorts are analyzed. That is, the frequency of repeated-pair surname marriages is statistically significant in marriages involving brides and grooms who carried 2 surnames. Interestingly, significant departures from random repetition of surnames occurred during the decade in which the great cholera epidemic affected Costa Rica and during the decade following it. This departure from panmixia supports the notion that mating patterns were altered as a result of the epidemic, a suggestion we made previously when we reported that inbreeding increased in these same decades (Madrigal and Ware 1997).

Lupus nephritis in an anti-nuclear antibody-negative young male. The simultaneous presence of class III and class V renal lesions.

We report about a 27-year-old white male, a known case of class III lupus nephritis with a very high anti-nuclear antibody (ANA) titer, who after 10 years of complete clinical and serological remission presented with sudden development of malar rash, proteinuria and an increase in the serum creatinine. Repeated serologic studies were all negative for ANA. A repeat kidney biopsy disclosed the presence of focal segmental glomerulosclerosis lupus nephritis (class IIIc) superimposed with a new membranous lupus nephritis (class V).

Percutaneous renal biopsy in the 1990s: safety, value, and implications for early hospital discharge.

To determine the parameters associated with significant bleeding and to examine the value of performing a renal biopsy, we studied 83 consecutive patients, including 24 renal allograft recipients, who had undergone percutaneous renal biopsy. The patients were stratified into four groups according to the percentage of decline in their hematocrit (Hct) at 24 hours postbiopsy, as follows: 10% or greater (n = 21; 25%) and less than 10% decline (n = 62; 75%). The latter group was further subgrouped into 5% to 10% (n = 22) and less than 5% decline (n = 40). There was a significant decline in Hct postbiopsy, with a linear correlation between the decrease in Hct at 6 and 24 hours (R2 = 0.47; P < 0.0001), suggesting that the former was a predictor of the latter. There was a linear correlation between the number of passes and number of cores obtained for the first four passes, but an inverse correlation when five passes or greater were required. Interestingly, there was no correlation between bleeding (>10% decline in Hct) and the number of passes or cores obtained. Gross hematuria and blood transfusion requirement were each encountered in three patients (3.6%). Importantly, the prebiopsy clinical diagnosis was altered in 18 of 59 native kidney biopsies (33%) and 10 of 24 transplant biopsies (41%). We conclude that percutaneous renal biopsy using an automated spring-loaded gun device coupled with ultrasound guidance is a safe technique and provides essential clinical information. Importantly, patients with a stable Hct at 6 hours were at low risk for bleeding at 24 hours while hospitalized. It remains to be determined if these findings could be extrapolated to early discharge from hospital.