Time to match; when do homologous chromosomes become closer?

In most eukaryotes, pairing of homologous chromosomes is an essential feature of meiosis that ensures homologous recombination and segregation. However, when the pairing process begins, it is still under investigation. Contrasting data exists in Mus musculus, since both leptotene DSB-dependent and preleptotene DSB-independent mechanisms have been described. To unravel this contention, we examined homologous pairing in pre-meiotic and meiotic Mus musculus cells using a three-dimensional fluorescence in situ hybridization-based protocol, which enables the analysis of the entire karyotype using DNA painting probes. Our data establishes in an unambiguously manner that 73.83% of homologous chromosomes are already paired at premeiotic stages (spermatogonia-early preleptotene spermatocytes). The percentage of paired homologous chromosomes increases to 84.60% at mid-preleptotene-zygotene stage, reaching 100% at pachytene stage. Importantly, our results demonstrate a high percentage of homologous pairing observed before the onset of meiosis; this pairing does not occur randomly, as the percentage was higher than that observed in somatic cells (19.47%) and between nonhomologous chromosomes (41.1%). Finally, we have also observed that premeiotic homologous pairing is asynchronous and independent of the chromosome size, GC content, or presence of NOR regions.

Chromosomal positioning in spermatogenic cells is influenced by chromosomal factors associated with gene activity, bouquet formation and meiotic sex chromosome inactivation.

Chromosome territoriality is not random along the cell cycle and it is mainly governed by intrinsic chromosome factors and gene expression patterns. Conversely, very few studies have explored the factors that determine chromosome territoriality and its influencing factors during meiosis. In this study, we analysed chromosome positioning in murine spermatogenic cells using three-dimensionally fluorescence in situ hybridization-based methodology, which allows the analysis of the entire karyotype. The main objective of the study was to decipher chromosome positioning in a radial axis (all analysed germ-cell nuclei) and longitudinal axis (only spermatozoa) and to identify the chromosomal factors that regulate such an arrangement. Results demonstrated that the radial positioning of chromosomes during spermatogenesis was cell-type specific and influenced by chromosomal factors associated to gene activity. Chromosomes with specific features that enhance transcription (high GC content, high gene density and high numbers of predicted expressed genes) were preferentially observed in the inner part of the nucleus in virtually all cell types. Moreover, the position of the sex chromosomes was influenced by their transcriptional status, from the periphery of the nucleus when its activity was repressed (pachytene) to a more internal position when it is partially activated (spermatid). At pachytene, chromosome positioning was also influenced by chromosome size due to the bouquet formation. Longitudinal chromosome positioning in the sperm nucleus was not random either, suggesting the importance of ordered longitudinal positioning for the release and activation of the paternal genome after fertilisation.

Laparoscopy and intraoperative enteroscopy, a helpful tool in a rare tumor (inflammatory fibroid polyp) of the small bowel. A case report.

INTRODUCTION AND IMPORTANCE: Inflammatory fibroid polyps (IFPs) are rare, benign tumors that can arise throughout the gastrointestinal tract, they are usually asymptomatic, and clinical presentation depends on the site of involvement. Gastric and colon IFPs are traditionally identified incidentally, whereas small intestinal lesions are often encountered in the setting of intussusception or during imaging studies. Complete resection via endoscopy or surgery is recommended. CASE PRESENTATION: Patient is a 52-year-old male without past medical history; he had a five-month history of mild colicky abdominal pain. A mass was detected in the small bowel, and surgery was decided. Since the mass was small a cooperative approach with an intraoperative enteroscopy was needed to locate the mass and achieve complete resection. DISCUSSION: IFPs of the small bowel require complete resection. Surgery should be performed as early as possible to prevent complications like intussusceptions, ischemia, and necrosis. CONCLUSIONS: In these rare tumors, the collaboration between surgeons and endoscopists is indispensable to improve the patient's prognosis.

"A hybrid approach for GISTs near the esophagogastric junction, a case report".

INTRODUCTION AND IMPORTANCE: Gastrointestinal stromal tumors are the most frequent mesenchymal tumors of the gastrointestinal tract. Complete resection of GISTs is the only chance of cure for patients. When these tumors are located near the esophagogastric junction, the surgical risk can cause deformity or stenosis in the gastric inlet, leading to higher complications and diminishing their quality of life. In such cases, a more sophisticated and tailored approach should be used. CASE PRESENTATION: We present the case of a 42-year-old female; she presented to our office with a 3-year history of nausea, vomiting and abdominal distension. Two GISTs were located near the EGJ, and with a combined approach we achieved complete resection. On follow-ups, the patient is doing well. CLINICAL DISCUSSION CONCLUSION: When diagnosis is confirmed, surgical resection must be the first choice for GISTs as complete surgical excision is the only permanent cure. The rise of endoscopic surgery has become a valuable tool and a critical element in surgery. Hybrid techniques that combine laparoscopic and endoscopic approaches can improve the patient's outcomes and provide better results.

A bleeding GIST in pandemic times, a cooperative approach to a delayed complication, a case report.

INTRODUCTION: Upper gastrointestinal bleeding is one of the major manifestations of the stomach's gastrointestinal stromal tumors; when gastric GISTs bleed, they are associated with a poor prognosis and must be treated promptly to avoid dangerous complications. A worrisome side effect of the Covid-19 pandemic is the delay in surgical treatment for seriously ill patients, a rise in surgical complications due to delayed care, lack of access to the healthcare system, and patients' hesitancy to seek care due to fear of the virus. In Ecuador, where limitations were present even in the absence of a pandemic, we are yet to fully know the full extent of the damage this pandemic has caused to ourselves and our patients. PRESENTATION OF CASE: We present the case of a 51-year-old female; she presented with upper gastrointestinal bleeding, and a gastric GIST was diagnosed. Due to the size and the symptoms, surgery was planned. Nonetheless, as Ecuador was hit hard by the Covid-19 pandemic to cope with the respiratory patients, surgeries were delayed or canceled. Our patient surgery was delayed for five months until she presented with severe gastrointestinal bleeding that required urgent action and care. Thankfully, she completely recovered. DISCUSSION AND CONCLUSIONS: This case is an example of the many complications we expect due to the pandemic; delay in treatment leads to troublesome complications. In these emergencies, time is of the essence, and surgical services must rise to the challenge; in a particular way, this case also proves that if there are the necessary tools to enhance the patient's recovery, we should hesitate to use them. Complete resection of the gastric GIST in a prompt matter must be done to avoid these potentially deadly complications.

Evaluación de una intervención educativa de enfermería dirigida a cuidadores principales de pacientes crónicos / Evaluation of an educational program for caregivers of patients with chronic diseases / Avaliação de uma intervenção educativa de enfermaria para cuidadores primários de pacientes crônicos

Es frecuente que los cuidadores principales de enfermos crónicos se conviertan en el "enfermo invisible", en la medida en que la atención y el \r\ncuidado están mayormente enfocados en el paciente, lo cual vulnera aspectos físicos, emocionales, espirituales y económicos de la persona que \r\ncuida. El objetivo de este estudio descriptivo con enfoque cualitativo es evaluar los resultados de implementar un programa educativo de inter\r\n-\r\nvención dirigido a 19 cuidadores principales de personas con enfermedad crónica, en seis delegaciones de la ciudad de Toluca, Estado de México. El estudio se desarrolló en tres etapas: diagnóstico, intervención y evaluación. Para impartir el programa educativo se realizaron visitas domiciliarias \r\nque se registraron en la bitácora de campo. \r\nEl programa denominado Cuidando a Cuidadores, se basa en los tres indicadores propuestos por \r\nNkongho: conocimiento, valor y paciencia. Consta de tres módulos, y en cada uno se realizaron tres tallerescon los 19 cuidadores,previo consen\r\n-\r\ntimiento informado. Los participantes expresaron haber adquirido conocimientos necesarios para el cuidado de su familiar; las dinámicas les \r\npermitieron reconocer fortalezas, debilidades, miedos, inseguridades y frustraciones; además, manifestaron sentirse satisfechos con el acom\r\n-\r\npañamiento y guía del equipo de salud que participó. Se puede afirmar que ser cuidador principal de un enfermo crónico es una experiencia \r\nque transforma la vida y requiere conocimiento, valor y paciencia para ejercer su tarea de manera hábil; esto puede incrementarse si se recibe \r\norientación por parte de los profesionales de enfermería

Regularly, the primary caregivers of chronically ill patients \r\nbecome the "invisible ill", to the extent that the attention and \r\ncare are mostly focused on the sick patiente, violating physical, \r\nemotional, spiritual and economic aspects of the caregiver. This \r\nproject analizes the results obtained from the implementation \r\nof an educational intervention program aimed at 19 primary \r\ncaregivers of people with chronic disease, in six delegations \r\nfrom the city of Toluca, State of Mexico. It was a descriptive \r\nstudy with a qualitative methodological approach. It was \r\ncarried out in three stages: diagnosis, intervention and evalua\r\n-\r\ntion. In order to provide the educational program, home visits \r\nwere performed using the log field. The program consisted \r\nof three modules, being imparted in workshops to the 19 \r\ncaregivers, with informed consent prior to the program. The \r\nresults were the following: Caregivers expressed that they had \r\nacquired knowledge required for the care of their family, the \r\ndynamics allowed them to recognize strengths, weaknesses, \r\nfears, insecurities and frustrations; they said they were satis\r\n-\r\nfied with the support and guidance of the health team that \r\nparticipated. It can be said that to be a primary caregiver for a \r\nchronically ill person is an experience that transforms life and \r\nrequires knowledge, courage and patience to perform their \r\nduties skillfully; these gratification may also be increased if you \r\nreceive guidance from nurses.

Muitas vezes, os cuidadores primários de pacientes crônicos se \r\ntornam o "paciente invisível", na medida em que a atenção e \r\nos cuidados são principalmente focados no doente, violando \r\naspectos físicos, emocionais, espirituais e econômicos do \r\ncuidador. Este projeto aborda os resultados obtidos na imple\r\n-\r\nmentação de um programa de intervenção educacional \r\nvoltado para 19 cuidadores primários de pessoas com doença \r\ncrónica, em seis delegações da cidade de Toluca, Estado do \r\nMéxico. O estudo era realizado em três etapas: diagnóstico, \r\nintervenção e avaliação. A fim de orientar sobre o programa \r\neducativo, foram realizadas visitas domiciliares, utilizando \r\no diário de campo. O programa consistiu de três módulos, \r\nconferindo-se oficinas aos 19 cuidadores, com prévio consen\r\n-\r\ntimento informado. Os cuidadores expressaram ter adquirido \r\nconhecimentos necessários para o cuidado de seu familiar \r\ne as dinâmica lhes permitiram reconhecer forças, fraquezas, \r\nmedos, inseguranças e frustrações. Eles disseram que estavam \r\nsatisfeitos com o apoio e orientação da equipe de saúde que \r\nparticipou. Pode-se dizer que ser o cuidador primário de um \r\npaciente crónico é uma experiência que transforma a vida e \r\nexige conhecimento, coragem e paciência para exercer as suas \r\nfunções com habilidade, podendo se aperfeiçoar se receber a \r\norientação de profissionais de enfermagem.

Protocolo de manejo del intento suicida en el Hospital del Salvador en Santiago de Chile / Suicide attempt management protocol in Hospital del Salvador in Santiago de Chile

Suicide is a global public health and social problem. It has important emotional consequences for the relatives of the deceased, as well as economic and emotional consequences for the rest of the community. Herein lies the importance of the early detection of potential cases and of utilizing adequate interventions. The present protocol was organized as a way of standardizing and giving the appropriate hierarchy to all interventions practiced in patients with suicidal risk within Hospital del Salvador.

El suicidio es un problema social y de salud pública en todo el mundo. Acarrea importantes consecuencias emocionales para las personas cercanas al fallecido y también consecuencias económicas y emocionales para el resto de la comunidad. De ahí la importancia de detectar tempranamente los potenciales casos y utilizar intervenciones adecuadas. El presente protocolo se estructuró como una manera de estandarizar y jerarquizar las intervenciones entregadas a pacientes con riesgo suicida en el Hospital del Salvador.

Prevalencia de displasia de vesícula biliar / Frequency of gallbladder dysplasia in gallbladders excised during cholecystectomy

Introducción: El cancer de vesícula biliar es una enfermedad muy frecuente en la actualidad, sobre todo en Chile, la India y Japón. La displasia de vesícula biliar es considerada como una lesión que precede la aparición de carcinoma vesicular. Objetivos: El objetivo de este estudio es determinar la prevalencia de la displasia de vesícula biliar en nuestro centro hospitalario y conocer sus características histológicas y clínicas. Material y Método: Los datos obtenidos de 1.237 informes de biopsias de colecistectomías realizadas en el hospital durante el año 2003 fueron procesados y analizados. Resultados: La prevalencia de la displasia de vesícula biliar fue de 2,5%. Del total de displasias (31 casos), 12 pertenecen a grado I (38,7%), 14 a grado II (45,16%) y 5 a grado lll-CIS ( carcinoma in situ 16%). La edad promedio en que se detectó la displasia de vesícula biliar fue de 54.7 años, siendo predominante en el sexo femenino con un 74,2%. Discusión: La displasia de vesícula biliar es una patología prevalente que sólo es posible diagnosticar mediante la histología realizada a los pacientes sometidos a colecistectomías.

Introduction: Gallbladder dysplasia is considered a premalignant stage, preceding the appearance of carcinoma. Aim: To assess the prevalence of gallbladder dysplasia in gallbladder biopsies. Material and methods: Review of pathology reports of 1237 gallbladders obtained during cholecystectomies, during 2003. Results: Thirty one reports informed the presence of dysplasia (2.5%). Of these, 12 were in stage 1 (39%), 14 were in stage 2 (45%) and 5 in stage 3-ISC (in-situ carcinoma, 16%). The mean age of patients with gallbladder dysplasia was 54 years. Discussion: Gallbladder dysplasia is common. The pathological study of the excised gallbladders is the only way to make the diagnosis.

Spatial and temporal variations in inhalable CuZnPb aerosols within the Mexico City pollution plume.

We report on the CuPbZn content of PM10 and PM2.5 samples collected from three sites (urban T0, suburban T1 and rural T2) during the Mexico City MILAGRO campaign of March 2006. Daytime city centre concentrations of summation operator CuZnPb(PM10) were much higher (T0 > 450 ng m(-3)) than at the suburban site (T1 < 200 ng m(-3)). Rural site (T2) summation operator CuZnPb(PM10) concentrations exceeded 50 ng m(-3) when influenced by the megacity plume but dropped to 10 ng m(-3) during clean northerly winds. Nocturnal metal concentrations more than doubled at T0, as pollutants became trapped in the nightly inversion layer, but decreased at the rural site. Transient spikes in concentrations of different metals, e.g. a "copper event" at T0 (CuPM10 281 ng m(-3)) and "zinc event" at T1 (ZnPM10 1481 ng m(-3)) on the night of March 7-8, demonstrate how industrial pollution sources produce localised chemical inhomogeneities in the city atmosphere. Most metal aerosols are <2.5 microm and SEM study demonstrates the dominance of Fe, Ti, Ba, Cu, Pb and Zn (and lesser Sn, Mo, Sb, W, Ni, V, As, Bi) in metalliferous particles that have shapes including spherical condensates, efflorescent CuZnClS particles, cindery Zn, and Cu wire. Metal aerosol concentrations do not change in concert with PM10 mass, which is more influenced by wind resuspension than industrial emissions. Metalliferous particles can induce cell damage, and PM composition is probably more important than PM mass, with respect to negative health effects, so that better monitoring and control of industrial emissions would likely produce significant improvements in air quality.

Entamoeba histolytica: cyst-like structures in vitro induction.

The cyst of Entamoeba histolytica is responsible for amebiasis infection. However, no axenic in vitro system exists that promotes mass encystation for studying this process of this human-infecting parasite. Cyst-like structures of E. histolytica obtained in this work were induced using TYI-S-33 media in combination with enterobacterias Escherichia coli and Enterococcus faecalis conditioned media, high CO2 tension and histamine. Cyst-like structures showed the same characteristics of a typical E. histolytica cyst: aggregation, resistance to 0.15% sarcosyl for 10 min, high signal of fluorescence under UV light when stained with 10% calcofluor M2r and the surface topology showed a wrinkled wall. In addition these structures are multinucleated with condensed chromatin attached to nuclear membrane, contain big vacuoles and ribonucleoproteic helices in the cytoplasm and also present a thin cell wall. Last all characteristics are all the same as a typical of E. histolytica cyst.

Entamoeba invadens: in vitro axenic encystation with a serum substitute.

The current media for axenic cultivation of Entamoeba histolytica and Entamoeba invadens are supplemented with bovine or equine serum, which provides several essential nutrients to amoebas. Serum has also been considered an essential component in encystation media for E. invadens. A substitute of serum, PACSR has been described as an alternative for growth of E. histolytica and also maintains growth of E. invadens. When PACSR was used instead of serum for encystation of E. invadens the efficiency was the same as for serum. Our present data show that PACSR can support the growth and induction of encystation of E. invadens strain IP-1.

Auxotrophy to lipoproteins of Entamoeba histolytica cultivated under axenic conditions.

Entamoeba histolytica grows in media without serum but with a mixture of aminoacids, vitamins, lipoproteins, free cholesterol, phospholipids and fatty acids called PACSR. The ability of lipoproteins and free lipids to support growth of three E. histolytica strains (HK9, HMI:IMSS and HM3:IMSS) was analysed. Tubes containing 5 ml culture medium, amino acids, vitamins and either 120-1,200 microg lipoproteins/ml or 0.017-0.10 mg free lipids/ml (predissolved in absolute ethanol) were inoculated with 1x10(4) trophozoites/ml and incubated at 37 degrees C for 72 h. Amoebae died within 12 h in the presence of any free lipid combination, while those having 240-480 mg lipoproteins/ml reached densities similar to or higher than those of controls (depending on strain). The addition of ethanol (0.1%) to the media produced stable lipid solutions and did not show significant adverse effects. Accordingly, E. histolytica is auxotrophic to lipoproteins and unable to use free cholesterol, phospholipids or fatty acids.

Axenic cultivation of Trichomonas vaginalis in a serum-free medium.

Mammalian serum or bovine serum albumin are essential for Trichomonas vaginalis cultivated under axenic conditions. Unfortunately, these components inhibit several biological properties of these parasites. PACSR is a serum replacement, free of bovine serum albumin. used for axenic cultivation of Entamoeba histolytica. We show that PACSR is also useful for axenic cultivation of T. vaginalis. Tubes containing 5.5 ml PEHP, or TYI basal media, plus 8% PACSR (v/v), were inoculated with 10(3) trichomonads/ml from 3 strains (GT-3, GT-13, and GT-15) and incubated at 36.5 C for 72 hr. Depending on the strain, cultures grown in PEHP plus PACSR reached densities of 50% (GT-13), 63% (GT-3), or 82% (GT-15) as compared to controls grown in PEHPS. On the other hand, yields of GT-3, GT-13, and GT-15 maintained in TYI plus PACSR were, respectively, 53%, 57%, and 67% among those of cultures grown in TYI-S-33. In all experiments, PEHPS and TYI-S-33 contained 8% bovine serum. Yields reached in PEHPS were 2.07+/-0.275 to 4.83+/-4.41 x 10(6) trichomonads/ml, whereas in TYI-S-33, densities were 1.68+/-0.315 to 4.16+/-8.07 x 10(6) trichomonads/ml. In conclusion, PACSR added to PEHP or TYI media is useful for axenic cultivation of T. vaginalis in the absence of serum or bovine serum albumin. PACSR could be useful in performing analyses of biological properties that are inhibited by serum or any of its components.

Isolation of an Entamoeba histolytica intracellular alkaline phospholipase A2.

The major hemolytic activity of Entamoeba histolytica is located in a subcellular fraction called P30. Its maximal effect is observed at pH 8.0 and 1 mM Ca2+ and is due to a phospholipase A (PLA). In the present study a membrane-associated phospholipase A2 was purified from P30 to homogeneity. P30 was fractionated with ethyl ether and the insoluble fraction was extracted with 1 M KCl. The KCl-soluble material was diluted ten times with 0.1 M TRIS-HCl (pH 9.5) and passed through a chromatofocusing column with a 9-4 pH gradient. Four peaks with PLA2 activity were obtained. By affinity chromatography, peak II, the one with the highest specific activity, was resolved in three more PLA2 peaks. Peak II.2 had the highest PLA2 specific activity. When analyzed by sodium dodecyl sulfate-polyacrylamide slab-gel electrophoresis under nonreducing conditions, peak II.2 yielded a single band with an apparent molecular mass of 30 kDa. Under reducing conditions the protein dissociated into two 15-kDa monomers. The purified PLA II.2 displayed its activity at the same conditions under which the P30 hemolytic activity was maximal. The isoelectric point of PLA II.2 was 7.0. The purification procedure described above provides sufficient material for determination of the relative importance of the enzyme in the E. histolytica pathogenic mechanisms.

Estudio in vivo de la respuesta pulpar de dos sistemas adhesivos de última generación / Pulp response of two new adhesives system. In vivo study

El objetivo de este estudio fue describir los cambios tisulares iniciales que suceden a nivel pulpar inducidos por la aplicación de dos acondicionadores dentinales (PRIME & BOND 2.1 Y PERMAQUIK). Se tomaron para este estudio 14 primeros premolares que serían extraídos por razones ortodónticas, en los cuales se ealizaron cavidades Clase V vestibulares; posterior mente se aplicaron los sistemas adhesivos y se obtulararon con su respectiva resina compuesta, las exodoncías donde se observó al microscopion de luz,presencia o ausencia de congestión vascular, regularidad o interrupción de la capa odontoblástica,presencia de capa de predentina y tipo de inflamación pulpar. Las placas se calorearón con Hematoxilina y Eosina. Los hallazgos de este estudio no evidencia respuestas pulpar después de la aplicación de éstos sistemas adhesivos, observándose los siguientes resultados: 1. Presencia de congestión vascular, 2. Regularidad de la capa odontoblástica;3.Presencia de la capa de predentina y 4. Ausencia de inflamación pulpar. Excepto en uno de los especímenes en el cual se encontró dentina reparativa de tipo osteodentina, después de haberle aplicado PRIME & BOND y realizar la exodoncia a los 80 días.

[Prevalence of digestive system cancer patients covered by the Mexican Institute of Social Security of the State of Sinaloa, Mexico]. / Prevalencia de cáncer del aparato digestivo en población derechohabiente del IMSS en el Estado de Sinaloa, México.

OBJECTIVE: To determine the frequency of malignant neoplasia of the digestive tract in patients seen at the IMSS concentration hospital in Culiacán, Sinaloa, México. METHODS: From 32,097 histopathologic studies performed at No. 1 Regional General Hospital Pathology Department in Culiacán, Sinaloa, 406 were identified as digestive tract malignant neoplasia (DTMN); patient's age and gender were analyzed as well as involvement site and histological type. Benign and metastasic neoplasias were excluded. RESULTS: DTMN prevalence: 1.26%; more affected: 60-69 years; male predominance (66%), p < 0.0001. As a whole, 47.2% of the studies reported stomach cancer; colorectal cancer: 17.5%; gall bladder and bile duct cancer; 8.4%; liver cancer: 8.1%; the remainder were located in other sites. DTMN rate by histologic type were similar to other concentration hospitals of the country. CONCLUSIONS: DTMN has an outstanding magnitude in IMSS Sinaloa patients if other hospital registrations are considered. There are possible regional factors that may contribute to this behavior.