Uso del aprendizaje automático en el diagnóstico del melanoma. Limitaciones por superar / Machine Learning in Melanoma Diagnosis. Limitations About to be Overcome

ANTECEDENTES: La clasificación automática de imágenes es una rama prometedora del aprendizaje automático (de sus siglas en inglés Machine Learning [ML]), y es una herramienta útil en el diagnóstico de cáncer de piel. Sin embargo, poco se ha estudiado acerca de las limitaciones de su uso en la práctica clínica diaria. OBJETIVO: Determinar las limitaciones que existen en cuanto a la selección de imágenes usadas para el análisis por ML de las neoplasias cutáneas, en particular del melanoma. MÉTODOS: Se diseñó un estudio de cohorte retrospectivo, donde se incluyeron de forma consecutiva 2.849 imágenes dermatoscópicas de alta calidad de tumores cutáneos para su valoración por un sistema de ML, recogidas entre los años 2010 y 2014. Cada imagen dermatoscópica fue clasificada según las características de elegibilidad para el análisis por ML. RESULTADOS: De las 2.849 imágenes elegidas a partir de nuestra base de datos, 968 (34%) cumplieron los criterios de inclusión. De los 528 melanomas, 335 (63,4%) fueron excluidos. La ausencia de piel normal circundante (40,5% de todos los melanomas de nuestra base de datos) y la ausencia de pigmentación (14,2%) fueron las causas más frecuentes de exclusión para el análisis por ML. DISCUSIÓN: Solo el 36,6% de nuestros melanomas se consideraron aceptables para el análisis por sistemas de ML de última generación. Concluimos que los futuros sistemas de ML deberán ser entrenados a partir de bases de datos más grandes que incluyan imágenes representativas de la práctica clínica habitual. Afortunadamente, muchas de estas limitaciones están siendo superadas gracias a los avances realizados recientemente por la comunidad científica, como se ha demostrado en trabajos recientes

BACKGROUND: Automated image classification is a promising branch of machine learning (ML) useful for skin cancer diagnosis, but little has been determined about its limitations for general usability in current clinical practice. OBJECTIVE: To determine limitations in the selection of skin cancer images for ML analysis, particularly in melanoma. METHODS: Retrospective cohort study design, including 2,849 consecutive high-quality dermoscopy images of skin tumors from 2010 to 2014, for evaluation by a ML system. Each dermoscopy image was assorted according to its eligibility for ML analysis. RESULTS: Of the 2,849 images chosen from our database, 968 (34%) met the inclusion criteria for analysis by the ML system. Only 64.7% of nevi and 36.6% of melanoma met the inclusion criteria. Of the 528 melanomas, 335 (63.4%) were excluded. An absence of normal surrounding skin (40.5% of all melanomas from our database) and absence of pigmentation (14.2%) were the most common reasons for exclusion from ML analysis. DISCUSSION: Only 36.6% of our melanomas were admissible for analysis by state-of-the-art ML systems. We conclude that future ML systems should be trained on larger datasets which include relevant non-ideal images from lesions evaluated in real clinical practice. Fortunately, many of these limitations are being overcome by the scientific community as recent works show

Machine Learning in Melanoma Diagnosis. Limitations About to be Overcome. / Uso del aprendizaje automático en el diagnóstico del melanoma. Limitaciones por superar.

BACKGROUND: Automated image classification is a promising branch of machine learning (ML) useful for skin cancer diagnosis, but little has been determined about its limitations for general usability in current clinical practice. OBJECTIVE: To determine limitations in the selection of skin cancer images for ML analysis, particularly in melanoma. METHODS: Retrospective cohort study design, including 2,849 consecutive high-quality dermoscopy images of skin tumors from 2010 to 2014, for evaluation by a ML system. Each dermoscopy image was assorted according to its eligibility for ML analysis. RESULTS: Of the 2,849 images chosen from our database, 968 (34%) met the inclusion criteria for analysis by the ML system. Only 64.7% of nevi and 36.6% of melanoma met the inclusion criteria. Of the 528 melanomas, 335 (63.4%) were excluded. An absence of normal surrounding skin (40.5% of all melanomas from our database) and absence of pigmentation (14.2%) were the most common reasons for exclusion from ML analysis. DISCUSSION: Only 36.6% of our melanomas were admissible for analysis by state-of-the-art ML systems. We conclude that future ML systems should be trained on larger datasets which include relevant non-ideal images from lesions evaluated in real clinical practice. Fortunately, many of these limitations are being overcome by the scientific community as recent works show.

Measuring Infection Transmission in a Stochastic SIV Model with Infection Reintroduction and Imperfect Vaccine.

An additional compartment of vaccinated individuals is considered in a SIS stochastic epidemic model with infection reintroduction. The quantification of the spread of the disease is modeled by a continuous time Markov chain. A well-known measure of the initial transmission potential is the basic reproduction number [Formula: see text], which determines the herd immunity threshold or the critical proportion of immune individuals required to stop the spread of a disease when a vaccine offers a complete protection. Due to repeated contacts between the typical infective and previously infected individuals, [Formula: see text] overestimates the average number of secondary infections and leads to, perhaps unnecessary, high immunization coverage. Assuming that the vaccine is imperfect, alternative measures to [Formula: see text] are defined in order to study the influence of the initial coverage and vaccine efficacy on the transmission of the epidemic.

Dioctophyme renale in a domestic cat (Felis catus): Renal location and nephrectomy.

Dioctophymosis is caused by Dioctophyme renale, nematode with indirect life cycle. Its intermediate host is a freshwater oligochaete and its definitive host is a wild or household carnivore. The adult nematode develops in the definite host, generally locating itself in the kidney. This article was meant to describe the first nephrectomy performed in a domestic cat due to renal dioctophymosis in Argentina. The subject showed a non-specific appearance of generally feeling ill, hematuria and mild diarrhea. It was diagnosed through abdominal ultrasound, followed by exploratory celiotomy and nephrectomy. After verifying absence of free specimens, the right kidney was removed. This organ was found to be enlarged in a spheroidal manner in contrast to the left kidney, with significant thickening of the renal capsule, excessive congestion of vessels and adhesions involving the caudal vena cava. An adult nematode was removed from the right kidney and identified as Dioctophyme renale. Reports of feline dioctophymosis are scarce being most of them necropsy findings. In this we are presenting a confirmed case of D. renale removed by surgery from a live cat. The results presented here reinforces the fact that cats are also appropriate definitive hosts for this parasite.

Effect of a quality improvement intervention to reduce the length of stay in appendicitis.

AIM: Determine the effect of an intervention to reduce the length of stay (LOS) in appendectomies. METHODS: A four-quarter quality improvement initiative was developed after approval by the facility Quality Management Department, including educational sessions about the best practices regarding the hospital care for patients with appendicitis and recommendations to limit the LOS for no complicated appendicitis unless associated conditions were present, monitoring of the LOS and feedback to the staff and leaders. RESULTS: 692 appendectomies were performed, 365 (52.7%)) of them during the intervention. The mean LOS was 3.94 days with a decreasing trend during the study period. The complicated appendicitis had a mean LOS of 6.42 days (SD, 3.85) during the baseline and 5.27 days (SD 2.50) during the intervention (p=0.03), representing a 17.9% reduction. The not complicated appendicitis during baseline had LOS of 3.82 days (SD 4.17) with a subsequent reduction to 2.95 days (SD 1.53) in the intervention. The total saving bed days during the intervention were 338.04 days, which 254.04 days (75.2%) were in non complicated appendectomies. One patient required readmission during the intervention because of an organ space surgical site infection, with proper recovery after antibiotic treatment. CONCLUSION: Our study provides evidence about the possibility to optimize the bed use with a simple educational intervention, and should be considered a step to achieve additional reductions in the hospital stay of patients who undergo laparoscopic appendectomies.

[Dose and efficacy of botulinum toxin in pediatric patients with spasticity]. / Dosis y eficacia de la toxina botulinica en pacientes pediatricos con espasticidad.

AIM: To evaluate the effectiveness of botulinum toxin in the treatment of upper and lower limb spasticity in pediatric patients in a real clinical setting. PATIENTS AND METHODS: A retrospective study was conducted based on information from clinical records of 79 pediatric patients with spasticity in different clinical forms and severity treated with botulinum toxin type A. The improvement of rigidity and mobility was estimated by the attending physician through physical examination, evaluating the gait, rating on the Ashworth scale and measurement of joint mobility angles using a goniometer. The number of injections, the interval between them, the site of application and the dose were recorded, considering the reduction of at least one point on the Ashworth scale or an increase in the degrees of joint mobility as treatment response. RESULTS: Patients received injections in a mean of 10 ± 7 muscles at intervals of 4 to 50 weeks (average: 13 ± 9 weeks). A 90% also received rehabilitation. The knee, ankle and wrist showed presented a higher percentage of improvement. An improvement in the degrees of movement was found in 24% of patients. CONCLUSION: The application of botulinum toxin type A was effective for the treatment of spasticity in the pediatric population.

TITLE: Dosis y eficacia de la toxina botulinica en pacientes pediatricos con espasticidad.Objetivo. Evaluar la efectividad de la toxina botulinica en el tratamiento de la espasticidad de los miembros superiores e inferiores en pacientes pediatricos en un entorno clinico real. Pacientes y metodos. Se realizo un estudio retrospectivo basado en el historial clinico de 79 pacientes pediatricos con espasticidad en diferentes formas clinicas y grados de afectacion tratados con toxina botulinica tipo A. La mejoria de la rigidez y movilidad fue estimada por el medico tratante mediante exploracion fisica, evaluando la marcha, la calificacion en la escala de Ashworth y la medicion de los angulos de movilidad articular mediante un goniometro. Se registro el numero de inyecciones, el intervalo entre ellas, el sitio de aplicacion y la dosis, y se considero una respuesta positiva al tratamiento la disminucion del al menos un punto en la escala de Ashworth o un incremento en los grados de movilidad articular. Resultados. Los pacientes recibieron inyecciones en 10 ± 7 musculos diferentes en intervalos de 4 a 50 semanas (media: 13 ± 9 semanas). Un 90% de los pacientes recibio rehabilitacion. Las articulaciones de la rodilla, el tobillo y la muñeca presentaron un mayor porcentaje de mejoria. En el 24% de los pacientes se encontro mejoria en los grados de movimiento articular. Conclusion. La aplicacion de toxina botulinica tipo A fue efectiva para el tratamiento de la espasticidad en la poblacion pediatrica.

The phenotypic correlates and quantitative genetics of masculinization in the rodent, Octodon degus.

This corrects the article DOI: 10.1038/hdy.2017.20.

The phenotypic correlates and quantitative genetics of masculinization in the rodent, Octodon degus.

In some mammals, female characteristics have been shown to depend, in part, on the intrauterine position during development of female fetuses relative to male fetuses. Females developing in close proximity to males show behavioral, physiological and life history characteristics that are masculinized. With the exception of one inconclusive study, nothing is known of the genetic basis of this phenomenon. In this paper, we reported an analysis of the quantitative genetic basis of masculinization, as indicated by the anogenital distance (AGD) at birth and weaning, in the rodent Octodon degus. Because AGD is related to weight, we included a genetic analysis of pup weight at birth and weaning. Pairwise correlations showed that AGD at birth varied negatively with litter size and parturition number but positively with weaning AGD, birth weight, dam AGD and percentage of males in the litter. AGD at weaning varied similarly except that it tended to vary positively with litter size. Genetic (co)variances of AGD at birth and weight at birth differed in females and males. In females, the best genetic model included substantial effects of direct additive, additive maternal and a negative additive genetic covariance between these two. In males, variances were small and there was difficulty in discriminating between additive maternal and common environmental variances. By weaning, genetic (co)variances had somewhat declined in weight and were not statistically significant in AGD in either sex. This paper showed the occurrence of both phenotypic and genetic components in masculinization with effects being greater in females.

Drought and salt tolerance enhancement of transgenic Arabidopsis by overexpression of the vacuolar pyrophosphatase 1 (EVP1) gene from Eucalyptus globulus.

Vacuolar solute accumulation has been shown to be a mechanism by which plants are capable of increasing drought and salt tolerance. The exposure of plants to NaCl induces H+ transport into the vacuole by specialized pumps. One of them corresponds to the vacuolar H+-pyrophosphatase, which generates a H+ gradient across the vacuolar membrane. In our laboratory we isolated the first cDNA sequence of a vacuolar pyrophosphatase type I (EVP1) from Eucalyptus globulus. Using real-time PCR we confirmed that EVP1 participates in Eucalyptus plants' response to drought and salt stress through an ABA independent pathway. Additionally, the overexpression of EVP1 in transgenic Arabidopsis resulted in an enhancement of drought and salt tolerance. Interestingly we established that the transgenic plants had a higher number of root hairs, which may have a positive effect on the plant's response to drought and salt stress. These results suggest that EVP1 plays an active role in abiotic stress tolerance in E. globulus, and that it may be potentially used to enhance drought and stress tolerance of plants.

Social dominance and behavioral consequences of intrauterine position in female groups of the social rodent Octodon degus.

Female phenotypic masculinization is a phenomenon widely described among mammals. In species that produce litters, female masculinization occurs in utero during late trimester of pregnancy as consequence of the intrauterine position phenomenon (IUP), affecting morphological, physiological and behavioral traits during adulthood. One morphological trait that is affected by IUP is anogenital distance (AGD) that is utilized as proxy of the female phenotypic masculinization. In rodents, IUP have ecological and behavioral effects including aggressiveness, territory marking, activity level, parental care and sociality. In this work, we evaluated how female masculinization (or feminization) affects aggressive behavior and determines social dominance, which in turn could lead to the structuring of social groups through dominance hierarchy formation in degus. We carried out a laboratory study where we established artificial social groups composed of females with the similar and different AGDs, and recorded all social interactions identifying initiator/recipient in dyad relationships and the nature of each interaction. Female aggression varied depending on the degree of females' masculinization, but only in mixed groups (those composed of females with different AGDs) was a hierarchical relationship observed. Furthermore, dominance hierarchies were constructed mostly on the basis of submissive, rather than aggressive interactions. Finally, female behavioral and morphological masculinization was not due to higher plasma testosterone levels, which would indicate that the masculinization of the female phenotype is the consequence of the organizational effects of steroid hormones during ontogeny.

[Why not revisiting tinidazole as potential treatment of odontogenic infections?]. / Por qué no reevaluar el tinidazol como tratamiento potencial de infecciones odontogénicas?

Tinidazole is a 5-nitroimidazole initially introduced into clinical medicine in 1969 for the treatment of unicellular parasites. Tinidazole offers selective bactericidal activity, not influenced by the inoculum size, against anaerobic bacteria, that make it of theoretical interest against periodontopathogen infections. This article reviews the required characteristics of an antibiotic directed to odontogenic anaerobic infections, as well as the pharmacodynamic pitfalls of common antibiotic treatments. In addition the in vitro, pharmacokinetic and pharmacodynamic properties of tinidazole are reviewed, assessing the degree of its adhesion to the required characteristics, as well as identifying the gaps to be fulfilled prior to its use in this medical field. Tinidazole offers interesting characteristics making worthy investigations as a candidate for the treatment of anaerobic odontogenic infections. \

Epidural analgesia in children: planning, organization and development of a new program.

BACKGROUND: The goal of the present work is to describe the development and results of the pediatric epidural analgesia program at the ''Hospital Nacional de Pediatria Prof. Dr. J. P. Garrahan'' in Argentina. METHODS: Patients with thoracotomy, abdominal surgery, osteotomy, amputations or severe trauma were included in the program. The program provided training to the entire staff, control and record of pain treatment and its consequences, 24 h a day availability of anesthesia staff and standard polices and procedures. RESULTS: One hundred fifty children under 16 years of age (median age 11 years, median weight 35 kg) were included in the program during the first 18 months. The median of maximum pain reported during activity was 1 (interquartile range 1 to 4 points) using the Visual Analogue Scale (VAS) or Objective Pain Scale (OPS). Eighty seven children (CI 95% 50% to 67%) presented with postoperative nausea and vomiting, urinary retention, itching, motor blockade or sedation. No patient presented with respiratory depression, hypotension, local anaesthetic toxicity, epidural catheter related infection or death during the program evaluation. The postoperative care program enabled a 98-day reduction in treatment in the intensive care unit. CONCLUSION: The safe use of pediatric epidural analgesia in general wards may require the careful selection of patients, systematic assessment by trained personnel, training of medical and nursing personnel, clear distribution of responsibilities, use of printed indications, systematic record of pain, sedation and complications, information and education of patients and parents, supply of systems for airway resuscitation and management and continuous quality control and revision of the methods.

Grupo Bacteroides fragilis en heces humanas no diarreicas y su sensibilidad antimicrobiana / Bacteroides fragilis group in non-diarrheic human feces and its antimicrobial susceptibility

Bacteroides es el género de bacterias anaerobias predominante en el colon humano, y sus diez especies son la causa de la mayoría de las infecciones anaerobias. Ya que casi todas las infecciones que causan son endógenas, el conocimiento de su resistencia es importante por la posible diseminación de ésta. Se analizaron 80 muestras de heces humanas que fueron sembradas en agar BBE (Bacteroides Bile Esculin) y KVLB (Kanamycin, Vancomycin, Laked Blood) y se incubaron en anaerobiosis 48 horas a 35 ºC. La identificación y la determinación de la sensibilidad se realizaron con los sistemas Rapid ID-32 A y ATB ANA (BioMerieux), respectivamente. En 64 de las 80 muestras (80%) se encontró al menos una especie del grupo B. fragilis, siendo B. uniformis y B. fragilis las más frecuentes (24,6% y 16,9%), y B. stercoris y B. eggerthii las menos frecuentes (0,7% y 2,1%). Las cepas mostraron resistencia a diversas penicilinas (de 93,1% a 40,2%), en ocasiones incluso en presencia de ácido clavulánico, así como a las cefalosporinas (de 31,0% a 52,1%), la clindamicina (32,2%) y el imipenem (10,3%). Los antibióticos más efectivos fueron la piperacilina y la ticarcilina asociados con inhibidores de betalactamasas, el cloranfenicol y el metronidazol (más del 90% de sensibilidad). Aunque ningún B. fragilis fue resistente a la clindamicina ni al metronidazol, un tercio de las cepas resistentes al imipenem eran de esta especie. La más resistente fue B. distasonis y la más sensible B. vulgatus. Ninguno de los fármacos evaluados fue efectivo contra todas las especies del grupo; en la mayoría de las especies hubo cepas con resistencia al imipenem, al metronidazol o a la clindamicina, lo que sugiere la existencia de mecanismos eficientes de transmisión de resistencia entre bacterias endógenas

Bacteroides is a predominant anaerobic bacteria of the human colon. Since the ten species of the Bacteroides fragilis group are responsible for most anaerobic endogenous infections, the antimicrobial resistance of these bacteria is of great concern due to the role they can play in the dissemination of resistance. Eighty non-diarrheic human feces samples were analyzed. Each sample was inoculated in BBE (Bacteroides Bile Esculin) and KVLB (Kanamycin, Vancomycin, Laked Blood) agar plates and were incubated in anaerobic conditions for 48 h at 35ºC. For identification and antimicrobial sensitivity, miniaturized systems for anaerobic bacteria (Rapid ID-32A and ATB ANA, Biomerieux) were used. Sixty-four (80%) of the samples were positive for at least one Bacteroides fragilis species; B. uniformis and B. fragilis were the most frequent species (24.6% and 16.9%); B. stercoris and B. eggerthii were the least frequent (0.7 and 2.1%). The strains showed resistance to different penicillins (40.2-93.1%), some even in the presence of beta-lactamase inhibitors; to cephalosporins (31.0-52.1%) and to frequently used antibiotics against anaerobes, such as clindamycin (32.2%) and imipenem (10.3%). The most effective antimicrobials against Bacteroides fragilis were piperacillin and ticarcillin combined with beta-lactamase inhibitors, as well as chloramphenicol and metronidazole (>90% susceptibility). None of the B. fragilis group were resistant to clindamycin or metronidazole, but one-third of the imipenem-resistant strains belonged to this species. The most resistant species was B. distasonis, while B. vulgatus was the most susceptible. None of the tested antimicrobials were effective against all ten species; the majority of the species had some isolates that were resistant to imipenem, metronidazole or clindamycin. This resistance pattern suggests the presence of efficient transmission mechanisms among these endogenous bacteria

[Bacteroides fragilis group in non-diarrheal human feces and its antimicrobial susceptibility]. / Grupo Bacteroides fragilis en heces humanas no diarreicas y su sensibilidad antimicrobiana.

Bacteroides is a predominant anaerobic bacteria of the human colon. Since the ten species of the Bacteroides fragilis group are responsible for most anaerobic endogenous infections, the antimicrobial resistance of these bacteria is of great concern due to the role they can play in the dissemination of resistance. Eighty non-diarrheic human feces samples were analyzed. Each sample was inoculated in BBE (Bacteroides Bile Esculin) and KVLB (Kanamycin, Vancomycin, Laked Blood) agar plates and were incubated in anaerobic conditions for 48 h at 35 degrees C. For identification and antimicrobial sensitivity, miniaturized systems for anaerobic bacteria (Rapid ID-32A and ATB ANA, Biomerieux) were used. Sixty-four (80%) of the samples were positive for at least one Bacteroides fragilis species; B. uniformis and B. fragilis were the most frequent species (24.6% and 16.9%); B. stercoris and B. eggerthii were the least frequent (0.7 and 2.1%). The strains showed resistance to different penicillins (40.2-93.1%), some even in the presence of beta-lactamase inhibitors, to cephalosporins (31.0-52.1%) and to frequently used antibiotics against anaerobes, such as clindamycin (32.2%) and imipenem (10.3%). The most effective antimicrobials against Bacteroides fragilis were piperacillin and ticarcillin combined with beta-lactamase inhibitors, as well as chloramphenicol and metronidazole (>90% susceptibility). None of the B. fragilis group were resistant to clindamycin or metronidazole, but one-third of the imipenem-resistant strains belonged to this species. The most resistant species was B. distasonis, while B. vulgatus was the most susceptible. None of the tested antimicrobials were effective against all ten species; the majority of the species had some isolates that were resistant to imipenem, metronidazole or clindamycin. This resistance pattern suggests the presence of efficient transmission mechanisms among these endogenous bacteria.