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.

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.

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.

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.

[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. \

[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.

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

Diarrhea associated with rotaviruses, enterotoxigenic Escherichia coli, Campylobacter, and other agents in Costa Rican children, 1976-1981.

Rotaviruses, enterotoxigenic Escherichia coli, Salmonella, Shigella, and parasites were investigated in outpatient diarrheic children, and in hospitalized diarrheic and non-diarrheic children, between January 1976 and June 1979. In outpatient cases studied within 4 days of onset of symptoms, rotaviruses were the most common agents (45.3%); E. coli heat-stable enterotoxin ranked second (13.4%); Shigella was third (8.1%); Salmonella was fourth (7.3%). In 63.2%, one or more enteric agents were detected. In hospitalized non-diarrheic children, asymptomatic shedding of pathogens was rarely observed. A later survey of outpatient diarrheic children revealed Campylobacter fetus jejuni in 8%. In 5.5 years of observation rotaviruses were endemic with excess frequency in the dry and cooler months of December and January. The excess occurrence of bacterial pathogens did not coincide with that of rotaviruses.

Piperacillin/tazobactam in the treatment of hospitalized patients with urinary tract infections: an open non-comparative and multicentered trial.

The aim of this multicentered, prospective and open study was to determine the clinical and bacteriological efficacy and safety of piperacillin/tazobactam (4g/500 mg IV tid) in the treatment of 79 adult patients with complicated urinary tract infections (UTI) requiring hospitalization. Forty-seven women and 32 men (mean age 54.2 years, and range 21-91) from 4 Argentinean and 6 Mexican hospitals were enrolled. Sixty-one clinically and bacteriologically evaluable patients were treated for a mean of 9.1 days (range 5-15). A favorable clinical response was seen in 83.6% and 80% at early and late assessment, respectively. Bacteriological eradication was achieved in 85.3% and 80% at early and late estimation, respectively. Escherichia coli was isolated in 33 cases, Klebsiella pneumoniae in 8, Enterococcus spp. in 7, Proteus mirabilis in 6, Pseudomonas aeruginosa in 3, Enterobacter spp. and Morganella morganii in 2. While 21% of all the clinical isolates were resistant to piperacillin, none of them was initially resistant to piperacillin/tazobactam. However, one female patient with a persistent UTI caused by E. coli developed resistance to piperacillin/tazobactam during treatment. A 64-year-old man with frontal meningioma developed purulent meningitis due to Enterobacter cloacae after neurosurgery. He was initially treated with ciprofloxacin, rifampin and amikacin and because of persistence of fever, he was moved to piperacillin/tazobactam. After 5 days of therapy, he developed coma secondary to intracranial hemorrhage and died. By then, the platelet count was normal (220,000/microliters), but the prothrombin time (19.5 seconds) and the partial thromboplastin time (63 seconds) were significantly prolonged. Our data suggest that piperacillin/tazobactam is a reliable therapy for complicated, non-complicated, community or hospital-acquired UTI.

Ultrastructural study of the skin after facial chemical peels and the effect of moisturization on wound healing.

Ultrastructural changes occurring in the skin at early times after chemical peels as well as effects on the wound healing with moisturization after these peels have been examined. This study evaluated the changes seen in the skin 3 days and 5 days after 35% trichloroacetic acid peels, and the effect of moisturization on this healing was evaluated. Biopsies at 3 days showed an outermost layer of necrotic stratum corneum and stratum granulosum and an underlying layer of new stratum corneum. There were increased cytoplasmic vacuoles in the keratinocytes of the stratum spinosum, stratum granulosum, and stratum basale layers. There was extensive intercellular spacing between the basal keratinocytes. At 5 days the necrotic layer of stratum corneum and stratum granulosum was gone. The lower epidermis at 5 days showed less intercellular spacing, and there was less vacuolization within keratinocytes. In seven of eight patients treated with moisturization after the peel (p = 0.0325), the ultrastructural changes at 5 days were consistent with a more advanced state of healing compared with those that were treated dry. Ultrastructural morphology at this time showed less intercellular spacing and fewer cytoplasmic vacuoles, indicative of an advanced state of wound repair. These moisturized skin specimens had returned to an almost normal state of structure compared with the skin that had been treated dry.

Subcutaneous approach for elevation of the malar fat pad through a prehairline incision.

In summary, vertical suspension of the malar fat pad has been a safe procedure that results in the creation of a more youthful cheek and a lessening of the prominence of the nasolabial folds. No complications were encountered in this series with the suture suspension of the malar fat pad.

[Determination of clostridium perfringens in pork sausages from the Metropolitan area of Costa Rica]. / Determinación de Clostridium perfringens en embutidos de carne de cerdo del area Metropolitana de Costa Rica.

The presence of C. perfringens was analyzed in 75 samples of pork sausages (chorizo, salchichon and bologna), obtained from five processing plants located in the Metropolitan Area of Costa Rica. Previously and after the biochemical identification of the strains, the most probable number (MPN) of C. perfringens per gram of food was determined and it varied from less than 3 to more than 2.4 x 10(5). There were significant statistical differences (p < 0.005) that support the need of employing biochemical tests for confirming C. perfringens in a given food. C. perfringens was present in 92% of the chorizos, in 28% of the bolognas and in 12% of the salchichon. Every positive sample was tested looking for at least one enterotoxigenic strain, using the reverse passive agglutination latex test; 8% of the tested strains were enterotoxigenic and corresponded to chorizo and bologna from one processing plant and chorizo from another plant. The results obtained in this study show that pork sausages, and not just not processed meats, are important as risk factors for food intoxication by C. perfringens.

[Presence of Clostridium perfringens in meat-based preparations in public food services in central San Jose, Costa Rica]. / Presencia de Clostridium perfringens en preparaciones a base de carne en servicios de alimentación pública del Cantón Central de San José, Costa Rica.

In Costa Rica there are a large number of public food services distributed along the country, where a considerable number of people eat daily. Clostridium perfringens is a bacteria associated with foodborne illness related, especially, to meat products kept for long time at temperatures under 70 degrees C. The aim of this study was to evaluate the public food services that use water baths for keeping food hot in order to establish the presence of C. perfringens in cooked bovine meat dishes and to evaluate the enterotoxigenic capacity of the strains isolated. 81 samples of cooked bovine meat plates coming from 27 public food services, located in the Central County of San José were analyzed. The methodology described by Labbe & Harmon for the isolation of C. perfringens was used in 10 g of sample. Also, the enterotoxigenic capacity of the strains was evaluated using the passive-reverse-latex-agglutination assay from Oxoid. From the 27 public food services analyzed, eight (30%) were positive in the three samplings done, nine (33%) were positive in one or two occasions, and ten (37%) were negative all times. This implies that in 17 (63%) of the establishments studied, the bacteria was isolated at least once. From the 81 preparations studied, 37 (46%) were positive for the bacteria. The temperatures at which food was kept varied from 56 to 82 degrees C, with an average of 68.7 degrees C. From the 37 strains identified as C. perfringens, 12 (32%) were positive for enterotoxin. In conclusion, the presence of C. perfringens in bovine meat dishes, maintained in water baths, represents an important risk for public health, and the temperature at which the preparation is kept is critical for the multiplication of the bacteria.

[Rotavirus and Campylobacter fetus jejuni associated with an outbreak of diarrhea in calves]. / Rotavirus y Campylobacter fetus jejuni asociados a un brote de diarrea en terneros.

Rotaviruses and Campylobacter fetus jejuni are ubiquitous agents of diarrheal disease in animals and humans. Under natural conditions they do not seem to cross inter-species barriers; a zoonosis has not been documented for man. However, animal rotaviruses might contribute to the emergence of new reassortment strains in view of their segmented genome, and thus, produce new antigenic variants. On the contrary, Campylobacter fetus jejuni produces a true zoonosis. Man acquires bacilli by ingesting water and foodstuffs contaminated with feces from infected animals. In an outbreak of diarrhea in 22 calves, rotavirus was detected in 8 (36%) and Campylobacter in 6 (27%). Three (14%) calves experienced double infection. There were no human cases involved in this outbreak.

[First isolation of Clostridium tetani from soils of Meseta Central, Costa Rica]. / Primer aislamiento de Clostridium tetani a partir de suelos de la Meseta Central de Costa Rica.

Clinical evidence has long pointed to the existence of Clostridium tetani in Costa Rica. Thirty soil samples were studied for clostridia, and two yielded six strains of C. tetani, four of which proved to be toxigenic when mice were inoculated intraperitoneally with the culture supernates. These four isolates could be neutralized when their toxic supernates were admixed with tetanus antitoxin.