Prevalence and clinical-epidemiologic characteristics of a Mexican population with metabolic (dysfunction) associated fatty liver disease: An open population study.

INTRODUCTION AND AIMS: The risk factors for fatty liver disease are frequent in the Mexican population and the available studies appear to underestimate its prevalence. Our aims were to know the prevalence of metabolic (dysfunction) associated fatty liver disease (MAFLD) in an open population and determine the clinical and sociodemographic characteristics, nutritional status, physical activity level, and prevalence of metabolic syndrome, in the affected population. MATERIALS AND METHODS: Volunteers from the general public were invited to take part in the study. Three separate questionnaires were applied to 1) determine the sociodemographic characteristics and health status of the participants, 2) evaluate the quality of their diet, and 3) to evaluate their level of physical activity. The participants underwent somatometry, laboratory tests, liver ultrasound, and FIB-4 index determination, and transition elastography (FibroScan®) was carried out on all subjects with signs suggestive of liver fibrosis that agreed to undergo the procedure. The statistical analysis was carried out using SPSS for Windows, version 22, software. RESULTS: A total of 585 volunteers were studied, resulting in a prevalence of MAFLD of 41.3%, a predominance of men above 50 years of age, poor dietary habits, and sedentary lifestyle. Male sex, obesity, metabolic syndrome, and elevated ALT were risk factors for the disease and 40% of those affected had advanced fibrosis. CONCLUSIONS: The prevalence of MAFLD in our population is one of the highest in the world. The conditioning factors of the disease can be modified. Therefore, public policies that redirect the current trend are required.

Evaluation of clinical and functional sequels of central serous chorioretinopathy. A case series analysis.

OBJECTIVE: To evaluate the clinical and functional sequelae of patients with a diagnosis of resolved CSC, through macular OCT, contrast sensitivity test, visual field 10-2 and Farnsworth D-15 color test. METHODS: 27 eyes of 26 individuals with CSC resolved by macular OCT were included and evaluated; the patients underwent a contrast sensitivity test with the Optec 6500 equipment, a 10-2 visual field with an Octopus 900 Haag-Streit, and a Farnsworth D-15 color test. RESULTS: Sequelae were observed in 20 eyes (74.1%) by macular OCT and in 21 (77.8%) in contrast sensitivity, predominantly type 2 defect. Also 27 (100%) had a visual field 10-2 altered corresponding to reduced foveal sensitivity, 11 eyes (40.7%) corresponded to central and paracentral scotomas. The color test showed alteration in 11 (40.7%) of the total eyes evaluated, finding tritanomaly in 9 of them (81.8%). No significant differences were observed in the studies between observation group vs the treatment group. CONCLUSIONS: CSC can leave sequelae in the visual quality of patients despite treatment in the acute phase. Visual acuity before and after treatment in the intervention group had no significant difference.

Nutritional imbalances in a Mexican vegan group: urgent need for country-specific dietary guidelines / Desequilibrios nutricionales en un grupo mexicano de veganos: necesidad de guías alimentarias para cada país

Introduction: vegan diets exclude the consumption of animal-derived products, and health advantages have been reported when followed. However, heterogeneous eating habits, food availability, and sociocultural characteristics among regions could lead to different physiological results Case reports: twelve patients following a strict vegan diet for an uninterrupted period of ≥ 3 years were subjected to clinical assessment. Patients significantly exceeded the suggested intake for sugar, presented six mineral deficiencies, and exhibited three vitamins below the recommended consumption. We further identified hyperglycemia, hypertriglyceridemia, subnormal serum vitamin B12 concentrations, as well as macrocytosis and microcytic anemia in several participants. Discussion: this Mexican vegan diet is strongly influenced by endemic and cultural adaptations that could limit the benefits reported in other populations. Professional guidance is required to avoid specific deficiencies with potential repercussions. We urge country-specific vegan guidelines considering local eating habits, food availability, and sociocultural perspectives around food (AU)

Introducción: la dieta vegana excluye el consumo de productos de origen animal y se ha vinculado con una disminución del riesgo de morbimortalidad. Sin embargo, los distintos hábitos alimentarios entre países podrían condicionar los beneficios reportados para las dietas basadas en vegetales. Casos clínicos: doce pacientes siguiendo una estricta dieta vegana por ≥ 3 años se sometieron a una evaluación clínica. Exhibieron una ingestión de azúcar que supera el consumo sugerido, presentaron tres deficiencias vitamínicas y seis de minerales. Se identificó la presencia de hiperglucemia, hipertrigliceridemia, concentraciones séricas subnormales de vitamina B12, macrocitosis y anemia microcítica en varios participantes. Discusión: la dieta vegana de este grupo resultó fuertemente influenciada por adaptaciones culturales que podrían limitar los beneficios reportados en otras poblaciones. Se requiere orientación profesional para evitar desequilibrios nutricionales. Enfatizamos la necesidad del desarrollo de guías alimentarias y de práctica clínica que consideren los hábitos alimentarios locales, la disponibilidad de alimentos en la región y las perspectivas socioculturales en torno a la dieta vegana (AU)

New Records of Ticks of Genus Amblyomma Koch, 1844 (Acari: Ixodidae) for Ecuador.

PURPOSE: In Ecuador, knowledge of the diversity and geographic distribution of ticks, as well as their importance as vectors, is scarce. Within the family Ixodidae, the genus Amblyomma is the most diverse and parasitizes wild and domestic animals. This genus is represented by 19 species in Ecuador, 12 of which occur in the continental territory and 7 in the Galapagos Islands. In this way, the objective of this work was to update the diversity of ticks reported for Ecuador on wild and domestic animals. METHODS: The specimens were collected manually on mammals and birds, in four localities belonging to the Sierra and Amazon of Ecuador and were kept in tubes with 96% ethyl alcohol. After that, all specimens were separated into immatures, males and females and were identified using their morphological characters. RESULTS: This study records Amblyomma coelebs Neumann, 1899, Amblyomma longirostre (Koch, 1844) Neumann, 1905 and Amblyomma varium Koch, 1844 for the first time in Ecuador. Thus, the genus Amblyomma is currently represented by 22 species. In addition, their hosts, distribution, and importance are also discussed. CONCLUSIONS: Knowing the diversity of ticks that wildlife possesses, its interrelation with the domestic fauna, and the possible pathogens that could be transmitting could significantly contribute to wildlife's conservation.

Daptomycin-Induced Posterior Reversible Encephalopathy Syndrome (PRES).

AIMS: To present a 60-year-old female patient who manifested clinical and radiological features of posterior reversible encephalopathy syndrome (PRES) following the administration of Daptomycin for glycopeptide-resistant Enterococcal urinary tract infection. MATERIAL: Case report. METHOD: Posterior reversible encephalopathy syndrome was diagnosed in our patient following the administration of Daptomycin based on clinical suspicion as well as brain CT and MRI imaging. RESULTS: The temporal association between the initiation of Daptomycin and the onset of PRES is highly suggestive of causality, and this is further supported by clinical and radiological resolution after Daptomycin was withdrawn. CONCLUSION: This is the first report of Daptomycin-induced posterior reversible encephalopathy syndrome.

Chlorophyll a Covalently Bonded to Organo-Modified Translucent Silica Xerogels: Optimizing Fluorescence and Maximum Loading.

Chlorophyll is a pyrrolic pigment with important optical properties, which is the reason it has been studied for many years. Recently, interest has been rising with respect to this molecule because of its outstanding physicochemical properties, particularly applicable to the design and development of luminescent materials, hybrid sensor systems, and photodynamic therapy devices for the treatment of cancer cells and bacteria. More recently, our research group has been finding evidence for the possibility of preserving these important properties of substrates containing chlorophyll covalently incorporated within solid pore matrices, such as SiO2, TiO2 or ZrO2 synthesized through the sol-gel process. In this work, we study the optical properties of silica xerogels organo-modified on their surface with allyl and phenyl groups and containing different concentrations of chlorophyll bonded to the pore walls, in order to optimize the fluorescence that these macrocyclic species displays in solution. The intention of this investigation was to determine the maximum chlorophyll a concentration at which this molecule can be trapped inside the pores of a given xerogel and to ascertain if this pigment remains trapped as a monomer, a dimer, or aggregate. Allyl and phenyl groups were deposited on the surface of xerogels in view of their important effects on the stability of the molecule, as well as over the fluorescence emission of chlorophyll; however, these organic groups allow the trapping of either chlorophyll a monomers or dimers. The determination of the above parameters allows finding the most adequate systems for subsequent in vitro or in vivo studies. The characterization of the obtained xerogels was performed through spectroscopic absorption, emission and excitation spectra. These hybrid systems can be employed as mimics of natural systems; the entrapment of chlorophyll inside pore matrices indicates that it is possible to exploit some of the most physicochemical properties of trapped chlorophyll for diverse technological applications. The data herein collected suggest the possibility of applying the developed methodology to other active, captive molecules in order to synthesize new hybrid materials with optimized properties, suitable to be applied in diverse technological fields.

Prospective Multicenter Observational Study of Overt Hepatic Encephalopathy.

BACKGROUND: Overt hepatic encephalopathy (OHE) is a frequent complication of decompensated cirrhosis. AIMS: A multicenter prospective observational study was performed to assess the most commonly recorded presenting manifestations of OHE and its associated health-care burden. METHODS: Qualifying patients must have experienced ≥1 OHE episode within 30 days of enrollment (qualifying OHE) and were followed for recurrence (on-study OHE). RESULTS: Two hundred and sixty-five patients were enrolled at 30 sites and followed for up to 9 months (mean 72 days). Seventy-two patients experienced 122 on-study episodes; with 72, 23, and 13 having ≥1, ≥2, or ≥3 on-study episodes with median days to occurrence of the 1st, 2nd, and 3rd episode of 34, 19, and 11, respectively. The most frequently recorded OHE manifestations included confusion (78 %), change in mental status (57 %), disorientation (48 %), lethargy (46 %), and asterixis (45 %). West Haven grade was used inconsistently and recorded for only 28 % of episodes. Most qualifying and on-study episodes occurred on rifaximin (60 and 82 %, respectively) and were associated with hospitalization (68 and 85 %, respectively). Twenty-three patients experienced ≥2 on-study episodes within 2 months of enrollment on average (median 45 days) and accounted for 60 % of on-study episodes. CONCLUSIONS: In this prospective study, OHE's most commonly recorded presenting manifestations included confusion, altered mental status, disorientation, lethargy, and asterixis. As reflected by frequent recurrence and hospitalizations, OHE, particularly the approximately 10 % of "high-resource-utilizing" patients with frequent recurrence, continues to pose a major unmet medical need and health-care burden despite the use of rifaximin.

Achalasia--An Autoimmune Inflammatory Disease: A Cross-Sectional Study.

Idiopathic achalasia is a disease of unknown etiology. The loss of myenteric plexus associated with inflammatory infiltrates and autoantibodies support the hypothesis of an autoimmune mechanism. Thirty-two patients diagnosed by high-resolution manometry with achalasia were included. Twenty-six specimens from lower esophageal sphincter muscle were compared with 5 esophagectomy biopsies (control). Immunohistochemical (biopsies) and flow cytometry (peripheral blood) analyses were performed. Circulating anti-myenteric autoantibodies were evaluated by indirect immunofluorescence. Herpes simplex virus-1 (HSV-1) infection was determined by in situ hybridization, RT-PCR, and immunohistochemistry. Histopathological analysis showed capillaritis (51%), plexitis (23%), nerve hypertrophy (16%), venulitis (7%), and fibrosis (3%). Achalasia tissue exhibited an increase in the expression of proteins involved in extracellular matrix turnover, apoptosis, proinflammatory and profibrogenic cytokines, and Tregs and Bregs versus controls (P < 0.001). Circulating Th22/Th17/Th2/Th1 percentage showed a significant increase versus healthy donors (P < 0.01). Type III achalasia patients exhibited the highest inflammatory response versus types I and II. Prevalence of both anti-myenteric antibodies and HSV-1 infection in achalasia patients was 100% versus 0% in controls. Our results suggest that achalasia is a disease with an important local and systemic inflammatory autoimmune component, associated with the presence of specific anti-myenteric autoantibodies, as well as HSV-1 infection.

Accessory liver lobes: anatomical description and clinical implications.

Accessory liver lobes are a rare condition and appear to be due to excessive development of the liver. The presence of an accessory hepatic lobe is often diagnosed incidentally and sometimes revealed if it develops torsion, especially in pedunculated forms. In most cases, the accessory lobe is located below the liver, i.e., infrahepatic. Riedel's lobe is the best-known example of an accessory lobe, corresponding to hypertrophy of segments V and VI. While accessories lobes can simulate tumors, there have also been reports of hepatocellular tumor(s) that developed in these accessory lobes. Based on a review of the literature, this update focuses on accessory hepatic lobes.

Differential cytokine expression and regulatory cells in patients with primary and secondary Sjögren's syndrome.

Sjögren's syndrome (SS) is an autoimmune disease characterized by lymphocytic infiltration of the salivary and lacrimal glands. The aim of the study was to characterize and compare the presence of diverse cytokines and regulatory T and B cells in lip minor salivary gland (MSG) biopsies from patients with primary Sjögren's syndrome (pSS), secondary SS (sSS), and patients with connective tissue disease (CTD) without (w/o) SS. We included samples of MSG from 15 pSS, 24 sSS (six scleroderma, nine rheumatoid arthritis and nine lupus patients) and 15 patients with CTD w/o SS. Tissues were examined by an indirect immunoperoxidase technique (goat polyclonal anti-human IL-19, goat polyclonal anti-human IL-22 or mouse monoclonal anti-human IL-24). To determine the subpopulation of CD4(+)/IL-17A(+)-, CD4(+)/IL-4(+)-, CD4(+)/IFN-É£(+)-expressing T cells, CD25(+)/Foxp3(+) Treg cells and CD20(+)/IL-10(+)-producing B cell subset, a double-staining procedure was performed. We estimated the mean percentage of positively staining cells in two fields per sample. CD4(+)/IFN-É£(+), CD4(+)/IL-4(+) and IL-22(+) cell percentages were elevated in both SS varieties; however, the cells were more prevalent in pSS. Patients with pSS had a high number of CD4(+)/IL-17A(+) and IL-19(+) T cells and a lower percentage of IL-24(+) cells (P < 0.05). The Treg and IL-10-producing B cells were increased in pSS (P < 0.05). Concluding, in our patients, a pro-inflammatory and regulatory balance coexists in SS, being both responses more intense in pSS. The explanation of these differences may be related to disease activity, disease duration and treatment.

Genome-wide functional screening identifies CDC37 as a crucial HSP90-cofactor for KIT oncogenic expression in gastrointestinal stromal tumors.

Most gastrointestinal stromal tumors (GISTs) contain KIT or PDGFRA kinase gain-of-function mutations, and therefore respond clinically to imatinib and other tyrosine kinase inhibitor (TKI) therapies. However, clinical progression subsequently results from selection of TKI-resistant clones, typically containing secondary mutations in the KIT kinase domain, which can be heterogeneous between and within GIST metastases in a given patient. TKI-resistant KIT oncoproteins require HSP90 chaperoning and are potently inactivated by HSP90 inhibitors, but clinical applications in GIST patients are constrained by the toxicity resulting from concomitant inactivation of various other HSP90 client proteins, beyond KIT and PDGFRA. To identify novel targets responsible for KIT oncoprotein function, we performed parallel genome-scale short hairpin RNA (shRNA)-mediated gene knockdowns in KIT-mutant GIST-T1 and GIST882. GIST cells were infected with a lentiviral shRNA pooled library targeting 11 194 human genes, and allowed to proliferate for 5-7 weeks, at which point assessment of relative hairpin abundance identified the HSP90 cofactor, CDC37, as one of the top six GIST-specific essential genes. Validations in treatment-naive (GIST-T1, GIST882) vs imatinib-resistant GISTs (GIST48, GIST430) demonstrated that: (1) CDC37 interacts with oncogenic KIT; (2) CDC37 regulates expression and activation of KIT and downstream signaling intermediates in GIST; and (3) unlike direct HSP90 inhibition, CDC37 knockdown accomplishes prolonged KIT inhibition (>20 days) in GIST. These studies highlight CDC37 as a key biologic vulnerability in both imatinib-sensitive and imatinib-resistant GIST. CDC37 targeting is expected to be selective for KIT/PDGFRA and a subset of other HSP90 clients, and thereby represents a promising strategy for inactivating the myriad KIT/PDGFRA oncoproteins in TKI-resistant GIST patients.

[Disseminated nodular primary localized cutaneous amyloidosis]. / Amiloidosis cutánea primaria localizada nodular con patrón diseminado.

Amyloid is a proteinaceous material that is deposited in the tissues in a large variety of clinical contexts; in the skin it can be found with or without concomitant systemic disease. Primary localized cutaneous amyloidosis encompasses those amyloidoses restricted to the skin without involvement of other systems. The most common forms within this group are macular and lichen amyloidosis. Nodular amyloidosis is extremely rare, and there are notable differences in clinical presentation, prognosis, histology, and pathogenesis between this entity and the macular and lichenoid variants. We report a new case of nodular primary localized cutaneous amyloidosis with disseminated plaques and nodules in which no systemic disease developed in the 3 years following the appearance of the lesions.

Amiloidosis cutánea primaria localizada nodular con patrón diseminado / Disseminated nodular primary localized cutaneous amyloidosis

El amiloide es un material proteináceo que se deposita en los tejidos en una gran variedad de situaciones clínicas; en la piel puede ser hallado con o sin afectación sistémica concomitante. La amiloidosis cutánea primaria localizada designa a aquellas amiloidosis con afectación exclusivamente cutánea, sin afectación a otros niveles. Las formas más comunes dentro de este grupo son la amiloidosis macular y el liquen amiloideo. La amiloidosis nodular es extremadamente infrecuente y mantiene importantes diferencias clínicas, pronósticas, histológicas y patogénicas con respecto a las variantes macular y liquenoide. Presentamos un nuevo caso de amiloidosis cutánea primaria localizada nodular con placas y nódulos diseminados, que no desarrolló afectación sistémica tras tres años desde el debut de las lesiones (AU)

Amyloid is a proteinaceous material that is deposited in the tissues in a large variety of clinical contexts; in the skin it can be found with or without concomitant systemic disease. Primary localized cutaneous amyloidosis encompasses those amyloidoses restricted to the skin without involvement of other systems. The most common forms within this group are macular and lichen amyloidosis. Nodular amyloidosis is extremely rare, and there are notable differences in clinical presentation, prognosis, histology, and pathogenesis between this entity and the macular and lichenoid variants. We report a new case of nodular primary localized cutaneous amyloidosis with disseminated plaques and nodules in which no systemic disease developed in the 3 years following the appearance of the lesions (AU)

Calidad de vida en niños y adolescentes con asma en una población mexicana / Quality of life in children and teenagers disgnosed with asthma in a Mexican population

Introducción: El propósito de este estudio fue evaluar la calidad de vida de niños y adolescentes con asma en la esfera biopsicosocial en una población mexicana. Metodología: Diseño del estudio descriptivo y correlacional. Muestreo no probabilístico, por conveniencia. Muestra de 108 participantes. Las mediciones fueron: Inventario de Calidad de Vida PedsQLTM y cedula de datos sociodemográficos. Resultados: el 81.4% de los participantes reportaron tres a más años de padecer asma, se identificó que 35.2% habían estado internados de una a dos veces en el último año. Las subescalas de funcionamiento físico (33.27%) y la emocional (33.24%) son más altas que la social y la escolar. La consistencia interna del instrumento PedsQLTM es aceptable con un Alpha de Cronbach de .86. Conclusiones: La media de calidad de vida de niños y adolescentes es alta en las subescalas de funcionalidad física y emocional. El Instrumento de Calidad de Vida en Pediatría, reportó confiabilidad aceptable y puede utilizarse en población mexicana. Se recomienda considerar en estudios con población pediátrica sean realizados en diversos periodos del año para precisar mejor la variable.

Quality of life in children and teenagers with asthma in a Mexican town Introduction: The purpose of this study was to evaluate the quality of life of children and teenagers with asthma on the biopsychosocial sphere in a Mexican town. Methodology: Design of descriptive study and co relational, not probabilistic sample for convenience. A sample with 108 participants. The measurements were: quality life inventory PedsQL and social demographic data schedule. Results: 81.4% of participants reported 3 thru more years suffering asthma, a 35.2% was indentified were in hospitals once to twice during the last year. The sub-scales of physical functioning (33.27%) and emotional (33.24%) are higher than social and scholar. The internal consistency of the instrument PedsQL is acceptable with an alpha Cronbach of .86. Conclusions: The average of quality of life of children and teenagers is high on the sub-scales of physical functionality and emotional. The quality of life in pediatrics instrument, reported acceptable trust and can be used on Mexican population. Is recommended to consider in studies with pediatric population to be made in different seasons of the year to precise the variable.

Mastopexia de aumento, técnica de quinta generación / Augmentation mastopexy, fifth generation technique

Presentamos una nueva técnica de mastopexia, más sencilla, y que evita recidivas además de disminuir el riesgo de carcinoma mamario. El estudio se realiza sobre 25 pacientes femeninas de 25a 50 años de edad, con ptosis mamaria. Con las pacientes de pie se realizó el marcaje tradicional; si las mamas son pequeñas se colocan implantes en el plano submuscular, y si son grandes, en el retroglandular. Para evitar recidivas se colocaron dos tirantesinternos con suturas irreabsorbibles. Si el complejo resultante glándula-implante es grande y pesado, se fija un tirante de la mama al periostio hemiclavicular y otro al periostio de la tercera costilla; si es pequeño o mediano, únicamente se fija a la costilla. Realizamos controles entre 1 mes y 3 años tras la intervención. Conseguimos corregir ptosis de entre 5 a 12cm., sin recidiva en ninguno de los controles, ni pseudo-ptosis postoperatoria. El ejercicio físico fue posible a los 15 días de la cirugía con el apoyo de un sujetador elástico. La cicatrización fue altamente satisfactoria. Las únicas complicaciones presentadas fueron dehiscencias parciales en 2 pacientes y sensación de ardor, tirantez y elongación dela areola en pacientes cuya ptosis excedía los 12cm y con areolas grandes. La facilidad de ejecución de la técnica y su seguridad, permiten que la cirugía sea ambulatoria. Proponemos esta técnica, que denominamos de quinta generación, que evita la cicatriz periareolar, la inframamaria, la vertical y la “T” invertida; además, elimina parte de ambos cuadrantes superiores de la mama, lo que disminuye notablemente la posibilidad de desarrollar ulteriores casos de carcinoma mamario y evita recidivas con el uso del tirante clavicular (AU)

We present a new mastopexy technique, simpler, which precludes the recidivism and reduces the risk of breast cancer. The study was based on 25 female patients between 25 to 50 years old with breast ptosis. With the patients standing up, was realized the traditional marks. If breasts were small, implants were positioned by submuscular way, and if bigger, the way was retroglandular. For recidivism prevention, it was positioned 2 internal straps; if the gland-implant was bigger and heavier an immobile strap from the breast to the clavicle periostium and to the 3rd rib, was realized; if it would result smaller or median size only were fixed to the third ribs with a dermal flap. Controls were realized between 1month to 3 years. Ptosis was corrected between 5 to 12cm without any recidivism, neither post-surgery pseudo-ptosis. With the support of an elastic brassier, physical exercise is recommended after15 days. The scarring was highly satisfactory. Complications were partial disruptions in 2 patients and ardors, tautness sensation and areolar enlargement in patients with more than 12cm ptosis and wide areola. Because of the execution simplicity and security, surgery was ambulatory. We propose this technique called 5th generation that precludes the periareolar, the inframamary, the vertical and the T scar; partial elimination of both upper breasts quadrants lessen the possibility of breast cancer in this upper area and ptosisrecidivism by the use of the internal straps (AU)

Síndrome hemolítico urémico asociado a infección por E. coli productor de toxina de shiga / Shiga-toxin-producing Escherichia coli and haemolytic uraemic syndrome

E.coli productora de Toxina Shiga (STEC), también conocida como E.coli entero- hemorrágica (EHEC), provoca un amplio espectro de manifestaciones clínicas, ya sea en brote o en forma esporádica, que incluyen dolor abdominal, fiebre leve o ausente, con o sin vómitos, diarreas (sanguinolenta o no), y complicaciones extraintestinales como: síndrome hemolítico urémico (SHU) que se observa hasta en un 5-6 por ciento de niños infectados, y púrpura trombocitopénico (7 por ciento de adultos). EI principal factor de virulencia es la producción de una familia de moléculas denominada STX (Shiga toxin), de las cuales STX 1 y 2 son las más frecuentes y característica distintiva de estos E.coli. EI principal serogrupo involucrado en Chile es O157:H7 pero también se han aislado 026, 055, 02, 0117 y 06 (generalmente clasificadas como E. coli serogrupo clásico, no enterohemorrágico). Es fundamental para el clínico conocer la epidemiología, sintomatología y los exámenes que permitan un diagnóstico rápido para manejo terapéutico adecuado, y así evitar las complicaciones enunciadas anteriormente.

Shiga toxin producing E.coli (STEC), also known as enterohemorragic E.coli (EHEC), are responsible for a wide variety of clinical manifestations, both epidemic and sporadic. These include abdominal pain, no fever to mild fever, with or without vomits, diarrhea (bloody or not) and extraintestinal complications, such as haemolytic uremic syndrome in about 5 to 6 percent of children, and trombocitopenic purpura in 1 percent adults. The main virulence factor involved is the production of STX (Shiga toxin). In Chile there is marked prevalence of E.coli serogroup 0157 :H7 in these cases, although it has been associated also to E.coli 026, 055,02,0117 and 06, considered as classic serogroup (not enterohemorragic). It is of outmost importance for clinicians to be aware of symptoms and signs of this disease, as well as diagnostic methods that allow a prompt and adequate treatment, in order to avoid complications.

Enhanced resonance light scattering properties of gold nanoparticles due to cooperative binding.

The interaction of 11-mercaptoundecanoic acid capped gold nanoparticles (MUA-GNPs) with europium ions and aminoacids has been studied by UV-Vis spectrophotometry, fluorescence, confocal fluorescence microscopy, resonance light scattering and TEM. Results demonstrated that hyper-Rayleigh scattering emission occurs upon the addition of lysine to the MUA-GNPs-Eu(III) system, thus providing an inherently sensitive method for lysine determination. The effects of geometrical factors of the gold nanoparticles (aspect ratio, particle size, cluster formation) and the surrounding medium (pH) on this behavior are discussed. The cooperative binding interactions of Eu(3+) and lysine with gold nanoparticles permitted the discrimination of lysine from other amino acids. The probable mechanism for the spectral changes and the enhanced resonance light scattering observed is outlined.

Valor de la biopsia gonadal en el diagnóstico de los desórdenes del desarrollo sexual / Diagnostic value of the gonadal biopsy in the disorders of sex development

La información proporcionada por la biopsia testicular en los estados intersexuales es primordial para la identificación, clasificación y detección precoz de neoplasias en estos pacientes. Antes de decidir una determinada opción terapéutica, los datos del estudio histológico de la biopsia gonadal deberán ser evaluados junto con los datos clínicos, genéticos, hormonales y moleculares. La diferenciación sexual es el resultado de complejos mecanismos genéticos y endocrinos, por ello, en el presente trabajo se revisan en primer lugar los acontecimientos que ocurren en el desarrollo embrionario de las gónadas, atendiendo a los mecanismos genéticos implicados en la determinación sexual y en la diferenciación testicular y del tracto urogenital. En segundo lugar se revisan los distintos tipos de gónadas observadas en los desórdenes del desarrollo sexual (síndromes de regresión testicular, cintilla fibrosa, disgenesia testicular, cintilla testículo, ovotestes, testículos microscópicamente normales y ovario), haciendo énfasis en los datos histológicos presentes en cada uno de ellos y en los datos diferenciales que permiten al patólogo distinguir unos desórdenes de otros, junto con la integración de los datos clínicos, genéticos hormonales y moleculares de cada una de estas situaciones. En tercer lugar se considera la incidencia de neoplasias, tanto en las diferentes situaciones clásicamente llamadas disgenesia gonadal, como de pseudohermafroditismos masculinos y hermafroditismo verdadero. Por último, se comentan las limitaciones de la biopsia gonadal que pueden impedir que el patólogo llegue a un diagnóstico preciso de un desórden del desarrollo sexual

The gonadal biopsy provides essential information for the identification, classification and early detection of neoplasias in patients with disorders of sex development. Histopathological findings in these cases must be analysed together with clinical, hormonal, genetic and molecular information before deciding a therapeutic option. Sexual differentiation is the result of multiple and complex genetic and endocrinal mechanisms; therefore, we first present the events taking place during gonadal embryonic development, focusing on the genetic mechanisms involved in sexual determination and the differentiation of the testis and the urogenital tract. In second place, we describe the different gonads in the intersexual states -in testicular regression syndrome, fibrous streak, testicular dysgenesis, streak testes, ovotestes and microscopically normal testes and ovaries-, highlighting the histological features and the differential findings that allow the pathologist to distinguish between these entities with the aid of clinical, genetic, hormonal and molecular information that are characteristic for each situation. In third place, we studied the incidence of neoplasias in gonadal dysgenesis, male pseudohermaphroditism and true hermaphroditism. Finally, we discuss the limitations of gonadal biopsy to achieve a correct diagnosis in the disorders of sex development