Virulence factor prediction in Streptococcus pyogenes using classification and clustering based on microarray data.

Interesting biological information as, for example, gene expression data (microarrays), can be extracted from publicly available genomic data. As a starting point in order to narrow down the great possibilities of wet lab experiments, global high throughput data and available knowledge should be used to infer biological knowledge and emit biological hypothesis. Here, based on microarray data, we propose the use of cluster and classification methods that have become very popular and are implemented in freely available software in order to predict the participation in virulence mechanisms of different proteins coded by genes of the pathogen Streptococcus pyogenes. Confidence of predictions is based on classification errors of known genes and repetitive prediction by more than three methods. A special emphasis is done on the nonlinear kernel classification methods used. We propose a list of interesting candidates that could be virulence factors or that participate in the virulence process of S. pyogenes. Biological validations should start using this list of candidates as they show similar behavior to known virulence factors.

A practical method for reducing blindness due to retinopathy of prematurity in a developing country.

BACKGROUND: Retinopathy of prematurity (ROP) is a common cause of blindness in countries with rapidly developing systems of neonatal care. At present, detection and treatment programs are not widely available in many regions of middle- and low-income countries. SUBJECT POPULATION: Case series. METHODS: An analysis was undertaken to determine in which neonatal intensive care units (NICUs) in Peru babies blind from ROP had been cared for. Demographic and hospital information was gathered for children blind from ROP presenting before the age of 5 years. NICUs with a high likelihood of having ROP-blind children were offered training and equipment designed to improve neonatal care. RESULTS: Ninety-one children with ROP blindness were identified. Twenty-six percent were <1000 g at birth, and 17% had birth weights of >1500 g. Forty-six percent came from NICUs in Lima. Interventional workshops emphasizing neonatal care and oxygen administration have been conducted thus far in six of the 13 largest NICUs in Lima. The percentage of at-risk babies being examined has generally increased, whereas the percentage of babies requiring treatment decreased in three NICUs and increased slightly in two, and no preworkshop data were available in one. CONCLUSION: This report represents the initial results of an evidence-based approach to decreasing blindness from ROP in Peru. Workshops emphasizing neonatal care, especially targeting oxygen administration, provide methods for improving care of at-risk babies.

The societal burden of blindness secondary to retinopathy of prematurity in Lima, Peru.

PURPOSE: To determine the cost-effectiveness of laser treatment for retinopathy of prematurity (ROP) in Lima, Peru. DESIGN: A cost-of-illness study (in US dollars) to determine the direct cost of treatment, the indirect lifetime cost of blindness, and the quality-adjusted life years. METHODS: The direct cost of ROP-related treatment was determined by reviewing data retrospectively from a social security sector hospital. The indirect cost was determined using national economic data of Peru published by the Central Information Agency (CIA), including the per capita gross domestic product, the sex-adjusted income distribution, and years spent in the work force. Indirect costs per child that were avoided by treatment were calculated using the known natural history of ROP vs evidence-based treatment. RESULTS: For ROP-related neonatal blindness in Peru, we estimate the total indirect cost saving at $197,753 per child and the direct cost of laser treatment at $2496 per child. The societal lifetime cost saving per child is estimated at $195,257. The mean annual income per educated adult in Peru is $8000 and treating 1 child is equivalent to employing 24 educated Peruvians per year. The generational cost savings for society is approximately $516 million, or the equivalent of 64,500 educated Peruvian work years. CONCLUSIONS: The societal burden of blindness far exceeds the costs of treatment per child. Proper screening and treatment of ROP prevents blindness and leads to substantial cost savings for society. Public health policy in Peru and other middle-income countries should consider financial impact when allocating healthcare resources.

Telemedicine screening for retinopathy of prematurity in developing countries using digital retinal images: a feasibility project.

PURPOSE: To determine the feasibility in a middle-level human development country of onsite training, image collection, Internet transfer, and remote grading of digital retinal images from babies screened for retinopathy of prematurity (ROP). METHODS: Two experienced nurses in a neonatal nursery in Lima, Peru, were trained to take posterior pole (30 degrees ) digital retinal images. Nurses obtained posterior pole retinal images from babies undergoing routine ROP screening and selected images for uploading via Internet for remote evaluation by five masked ROP experts. Results of gradings were compared with same-day clinical diagnostic examinations by an experienced ophthalmologist. Success rates for image acquisition and transfer for grading by expert readers were calculated. RESULTS: Serial image sets from 26 of the 28 babies enrolled in this study were obtained; two babies were too unstable for imaging. Fifty-six of 58 (96.6%) imaging sessions were successful in obtaining retinal images. Three hundred thirty of 336 (98.2%) images obtained were successfully uploaded to an interactive database. Remote graders judged 93.6% to 97.3% of image sets suitable for ROP grading. Preliminary results indicate sensitivities for detection of serious ROP from 45.5% to 95.2% among individual readers, with specificities of 61.7% to 96.2% when images were gradable. CONCLUSIONS: A telemedicine approach for ROP screening using digital retinal images obtained by nonophthalmologists is feasible in rapidly developing countries that lack ROP-trained ophthalmologists. If remote grading of digital images is validated as an effective method for identifying referral-warranted ROP (RW-ROP), images obtained by nonphysicians may provide a means of identifying babies who require a diagnostic examination by an ophthalmologist.

Characteristics of infants with severe retinopathy of prematurity in countries with low, moderate, and high levels of development: implications for screening programs.

OBJECTIVE: Retinopathy of prematurity (ROP) is a potentially avoidable cause of blindness in children. The proportion of blindness as a result of ROP varies greatly among countries depending on their level of development, being influenced by the availability of neonatal care, neonatal outcomes, and whether effective screening and treatment programs are in place. The objective of this study was to compare characteristics of premature infants who developed severe ROP between 1996 and 2002 in highly developed countries with less developed countries. METHODS: This was an observational study. A questionnaire was completed by ophthalmologists in countries with low, moderate, and high development rankings (3 highly developed countries and from 10 less well-developed countries) who screen for ROP in which they supplied birth weights and gestational ages (GAs) of infants who were treated for threshold ROP or identified with more advanced stages of the disease. Birth weights and GAs of infants with severe ROP were measured. RESULTS: The mean birth weights of infants from highly developed countries ranged from 737 to 763 g compared with values ranging from 903 to 1527 g in less developed countries. Mean GAs of infants from highly developed countries ranged from 25.3 to 25.6 weeks compared with 26.3 to 33.5 weeks in less developed countries. A total of 13.0% of 1091 infants from poorly developed countries exceeded United Kingdom screening criteria; 3.6% exceeded a criteria of <34 weeks' GA and/or <1750 g birth weight. CONCLUSIONS: These findings suggest that larger, more mature infants are developing severe ROP in countries with low/moderate levels of development compared with highly developed countries. ROP screening programs need to use criteria that are appropriate for their local population.

Educación prenatal para la lactancia al seno / Prenatal education for breast-feeding

A un grupo de 25 mujeres embarazadas, seleccionadas por tener pensado lactar artificialmente a su hijo, se les impartieron una serie de pláticas sobre alimentación al seno. Paralelamente se escogieron, bajo los mismos criterios, otras 25 madres gestantes, las cuales constituyeron un grupo testigo. Después de nacer los niños, a las cuatro semanas de vida, se les visitó en su domicilio y se investigó el tipo de lactancia que ofrecían a los infantes. Los resultados mostraron que en el grupo experimental, 18 de las madres brindaban la alimentación al seno, mientras que en el grupo contraste sólo cuatro mujeres amamantaban a sus hijos. El estudio hace resaltar la importancia de la educación sobre la lactancia natural, durante la etapa prenatal