[Artificial Intelligence: accuracy for the diagnosis of precancerous lesions of the cervix]. / Inteligencia Artificial: precisión diagnóstica de lesiones preneoplásicas de cérvix uterino.

INTRODUCTION: To compare the diagnostic sensitivity of artificial intelligence (AI) assisted videocolposcopy with standard videocolposcopy performed by specialist colposcopists. METHODS: A descriptive retrospective cross-sectional study, 782 anonymized medical records from the Computerized System for Screening (SITAM) of women who underwent videocolposcopy with AI and colposcopy with common videocolposcopy performed by specialists, with their corresponding biopsies (gold standard) were analyzed. The relationship between the results of IA videocolposcopy and regular videocolposcopy and the results of biopsies was evaluated. The overall accuracy of each diagnostic procedure was calculated. The sensitivity and concordance of the results of AI videocolposcopy with the gold standard (biopsy) were determined. RESULTS: A total of 395 patient records of patients with IA videocolposcopy and 387 with regular videocolposcopy were analyzed. The accuracy of results was 80% (IC 95%: 75-83%) in IA videocolposcopy and 65% (IC 95%: 60-69%) in regular videocolposcopy (p<0.001). Videocolposcopy results with IA and common colposcopy were significantly correlated with biopsy results, rs=0.75 vs. rs=0.57 respectively (p<0.001). The sensitivity of videocolposcopy with AI was 96% (95% CI: 94-98%), and 93% (95% CI: 89-95%) for regular colposcopy. The overall agreement of colposcopic impressions classified by videocolposcopy with AI and disease was higher than that of colposcopic interpretation by colposcopists (90% vs. 83%, Kappa 0.59 vs. 0.47, p<0.001). CONCLUSION: The high diagnostic accuracy of AI videocolposcopy allows obtaining highly sensitive studies that help in the early detection of precursor lesions of cervical neoplasia.

Introducción: Objetivo: comparar sensibilidad diagnóstica de videocolposcopia con inteligencia artificial (IA) auxiliar, con la videocolposcopia común realizada por colposcopistas. Métodos: Estudio descriptivo de corte transversal retrospectivo, en 782 historias clínicas anonimizadas del Sistema Informático para el Tamizaje (SITAM), de mujeres a las cuales se les efectuaron videocolposcopia con IA y colposcopías con videocolposcopio común realizadas por especialistas, con sus biopsias (gold standard). Se evaluó la relación entre los resultados de videocolposcopia con IA y videocolposcopia común con resultados de las biopsias. Se calculó precisión global de cada procedimiento diagnóstico. Se determinó sensibilidad y concordancia de los resultados de la videocolposcopia con IA, con el gold standard. Resultados: Se analizaron 395 historias clínicas de pacientes con videocolposcopia con IA y 387 con videocolposcopia común. La precisión diagnóstica de resultados fue 80% (IC 95%: 75-83%) en videocolposcopias con IA y 65% (IC 95%: 60-69%) en videocolposcopia común (p<0.001). Los resultados de videocolposcopia con IA y colposcopia común se correlacionaron significativamente con los resultados de las biopsias, rs=0.75 vs. r s=0.57 respectivamente (p<0.001). La sensibilidad de videocolposcopia con IA fue 96% (IC 95%: 94-98%), y 93% (IC 95%: 89-95%) en colposcopías comunes. La concordancia general de las impresiones colposcópicas clasificadas por videocolposcopia con IA y enfermedad fue mayor que la de la interpretación colposcópica de los colposcopistas (90% frente a 83%, Kappa 0.59 frente a 0.47, p<0.001). Conclusión: La alta precisión diagnóstica de videocolposcopia con IA permite aumentar la sensibilidad del estudio y mejorar la detección precoz de lesiones precursoras de neoplasias cervicouterinas.

Substance abuse and white matter: Findings, limitations, and future of diffusion tensor imaging research.

Individuals who abuse substances often differ from nonusers in their brain structure. Substance abuse and addiction is often associated with atrophy and pathology of grey matter, but much less is known about the role of white matter, which constitutes over half of human brain volume. Diffusion tensor imaging (DTI), a method for non-invasively estimating white matter, is increasingly being used to study addiction and substance abuse. Here we review recent DTI studies of major substances of abuse (alcohol, opiates, cocaine, cannabis, and nicotine substance abuse) to examine the relationship, specificity, causality, and permanence of substance-related differences in white matter microstructure. Across substance, users tended to exhibit differences in the microstructure of major fiber pathways, such as the corpus callosum. The direction of these differences, however, appeared substance-dependent. The subsample of longitudinal studies reviewed suggests that substance abuse may cause changes in white matter, though it is unclear to what extent such alterations are permanent. While collectively informative, some studies reviewed were limited by methodological and technical approach. We therefore also provide methodological guidance for future research using DTI to study substance abuse.

Strong infrared photoluminescence in highly porous layers of large faceted Si crystalline nanoparticles.

Almost all physical processes in solids are influenced by phonons, but their effect is frequently overlooked. In this paper, we investigate the photoluminescence of large silicon nanoparticles (approximately 100 nm size, synthesized by chemical vapor deposition) in the visible to the infrared detection range. We find that upon increasing laser irradiance, an enormous photoluminescence emission band appears in the infrared. Its intensity exhibits a superlinear power dependence, increasing over four orders of magnitude in the investigated pump power range. Particles of different sizes as well as different shapes in porous layers are investigated. The results are discussed taking into account the efficient generation of phonons under high-power pumping, and the reduced capability, porosity dependent, of the silicon nanoparticles to exchange energy with each other and with the substrate. Our findings are relevant for heat management strategies in silicon.

Universal trees based on large combined protein sequence data sets.

Universal trees of life based on small-subunit (SSU) ribosomal RNA (rRNA) support the separate mono/holophyly of the domains Archaea (archaebacteria), Bacteria (eubacteria) and Eucarya (eukaryotes) and the placement of extreme thermophiles at the base of the Bacteria. The concept of universal tree reconstruction recently has been upset by protein trees that show intermixing of species from different domains. Such tree topologies have been attributed to either extensive horizontal gene transfer or degradation of phylogenetic signals because of saturation for amino acid substitutions. Here we use large combined alignments of 23 orthologous proteins conserved across 45 species from all domains to construct highly robust universal trees. Although individual protein trees are variable in their support of domain integrity, trees based on combined protein data sets strongly support separate monophyletic domains. Within the Bacteria, we placed spirochaetes as the earliest derived bacterial group. However, elimination from the combined protein alignment of nine protein data sets, which were likely candidates for horizontal gene transfer, resulted in trees showing thermophiles as the earliest evolved bacterial lineage. Thus, combined protein universal trees are highly congruent with SSU rRNA trees in their strong support for the separate monophyly of domains as well as the early evolution of thermophilic Bacteria.

Phylogenetic analyses do not support horizontal gene transfers from bacteria to vertebrates.

Horizontal gene transfer (HGT) has long been recognized as a principal force in the evolution of genomes. Genome sequences of Archaea and Bacteria have revealed the existence of genes whose similarity to loci in distantly related organisms is explained most parsimoniously by HGT events. In most multicellular organisms, such genetic fixation can occur only in the germ line. Therefore, it is notable that the publication of the human genome reports 113 incidents of direct HGT between bacteria and vertebrates, without any apparent occurrence in evolutionary intermediates, that is, non-vertebrate eukaryotes. Phylogenetic analysis arguably provides the most objective approach for determining the occurrence and directionality of HGT. Here we report a phylogenetic analysis of 28 proposed HGT genes, whose presence in the human genome had been confirmed by polymerase chain reaction (PCR). The results indicate that most putative HGT genes are present in more anciently derived eukaryotes (many such sequences available in non-vertebrate EST databases) and can be explained in terms of descent through common ancestry. They are, therefore, unlikely to be examples of direct HGT from bacteria to vertebrates.

Prediction of amino acid sequence from structure.

We have developed a method for the prediction of an amino acid sequence that is compatible with a three-dimensional backbone structure. Using only a backbone structure of a protein as input, the algorithm is capable of designing sequences that closely resemble natural members of the protein family to which the template structure belongs. In general, the predicted sequences are shown to have multiple sequence profile scores that are dramatically higher than those of random sequences, and sometimes better than some of the natural sequences that make up the superfamily. As anticipated, highly conserved but poorly predicted residues are often those that contribute to the functional rather than structural properties of the protein. Overall, our analysis suggests that statistical profile scores of designed sequences are a novel and valuable figure of merit for assessing and improving protein design algorithms.

A double-blind study of hyposensitization with an alginate-conjugated extract of Dermatophagoides pteronyssinus (Conjuvac) in patients with perennial rhinitis. II. Immunological aspects.

In a 2-year double-blind placebo controlled study an immunological evaluation was carried out on 33 patients (15 males, 18 females, mean age 29.2 years) with mite-induced perennial rhinitis who were submitted to specific immunotherapy (IT) with an alginate-conjugated extract of D. pteronyssinus. The behaviour of IgE, IgG, IgG1 and IgG4 antibodies specific to D. pteronyssinus and its major allergen Der p1 was characterized by assessment of their changes in serum, and changes in IgG in nasal secretions during the treatment. The placebo-treated patients did not show any significant variation in the levels of specific antibodies, while in the actively treated patients we found: a statistically significant decrease (P less than 0.005) of specific IgE, a statistically significant increase of specific IgG (P less than 0.005), IgG1 (P less than 0.005) and IgG4 (P less than 0.005) in serum and a statistically significant increase (P less than 0.001) of specific IgG in nasal secretions. The IgG response showed an early relative predominance of the IgG1 subclass and a late absolute predominance of IgG4 subclass, that confirmed the model of IgG4 restriction in prolonged allergen stimulation. No correlation was found between immunological and clinical data.

Allergen specific IgG subclass antibody response in hyposensitization with Dermatophagoides pteronyssinus extract.

Most of the controlled trials of specific immunotherapy (SIT) with house dust mite showed a good clinical efficacy of different kinds of extract after variable periods of treatment. However, few of them looked at all the parameters available to monitor this therapy, such as threshold dose of specific provocation test, end point titration and immunological variations. In particular, the behaviour of specific IgE antibodies is not completely known, while, in more recent studies, mite specific IgG antibodies have been shown to increase even in the early stages of treatment. Few data are available on mite specific IgG1-4 subclasses. The preliminary results of a double blind placebo controlled trial we performed with alginate conjugated Dermatophagoides pteronyssinus extract seem to indicate a good clinical and immunological response to this kind of extract. Moreover, we observed a significant increase of specific IgG antibodies, total and subclasses IgG1.2.4, with a prevalence of IgG4 subclass after three months of SIT. After two years of SIT mite specific IgG1 antibodies showed a tendency to decrease, while IgG4 antibodies maintained a constantly high level.