Microscopic Analysis of Nuclear Speckles in a Viviparous Reptile.

Nuclear speckles are compartments enriched in splicing factors present in the nucleoplasm of eucaryote cells. Speckles have been studied in mammalian culture and tissue cells, as well as in some non-mammalian vertebrate cells and invertebrate oocytes. In mammals, their morphology is linked to the transcriptional and splicing activities of the cell through a recruitment mechanism. In rats, speckle morphology depends on the hormonal cycle. In the present work, we explore whether a similar situation is also present in non-mammalian cells during the reproductive cycle. We studied the speckled pattern in several tissues of a viviparous reptile, the lizard Sceloporus torquatus, during two different stages of reproduction. We used immunofluorescence staining against splicing factors in hepatocytes and oviduct epithelium cells and fluorescence and confocal microscopy, as well as ultrastructural immunolocalization and EDTA contrast in Transmission Electron Microscopy. The distribution of splicing factors in the nucleoplasm of oviductal cells and hepatocytes coincides with the nuclear-speckled pattern described in mammals. Ultrastructurally, those cell types display Interchromatin Granule Clusters and Perichromatin Fibers. In addition, the morphology of speckles varies in oviduct cells at the two stages of the reproductive cycle analyzed, paralleling the phenomenon observed in the rat. The results show that the morphology of speckles in reptile cells depends upon the reproductive stage as it occurs in mammals.

Genotoxicity in the oral cells of older people from a Brazilian rural area: a population-based study

Abstract The purpose of this population-based, observational, and cross-sectional study was to evaluate alterations in the oral cells of a population of older people from a Brazilian rural area, using the micronucleus technique to investigate possible associated genotoxic factors. A questionnaire was applied and clinical examination and collection of oral mucosal cells were performed for all older people (≥ 60 years) from a town in southern Brazil. Demographic and socioeconomic variables, deleterious habits (drinking and tobacco use), presence of gastro-oesophageal reflux disease (GERD), and the use of proton pump inhibitors (PPIs) were considered the exposure variables, whereas metanuclear changes (MCs) and the prevalence of cell micronuclei (MN) were considered outcomes. Out of 489 older people, 447 were included in the study, among whom 50.8% were men with a mean age of 70.9 years and 83.9% had a monthly family income greater than US$ 500.00. GERD symptoms were present in 36.2% of the individuals, and 29.1% used PPIs daily, 53.3% consumed alcoholic beverages, and 46.7% used tobacco. The analysis of 1,000 oral mucosal cells per subject showed a MN frequency of 0-2 per individual, and MCs were detected with an average of 15 units per individual (median = 11 per individual). Poisson regression did not show statistical association between the exposure variables and the outcomes (presence of MN and MCs), except for the use of PPIs, which was a protective factor for the prevalence of MN [PR 0.6 (CI 0.3-0,9)]. Age, sex, family income, tobacco use and drinking, and GERD were not associated with the number of MN and MCs in oral mucosal cells of the investigated older people.

Caracterización morfométrica nuclear de glándulas mamarias sanas en mujeres adultas mayores

Introducción: Las glándulas mamarias son órganos que durante las diferentes etapas de la vida en la mujer sufren modificaciones, donde se involucran los procesos de proliferación, diferenciación y apoptosis, bajo el control hormonal. Sin embargo, una vez que cesan dichas influencias hormonales ocurren cambios que llevan a la involución de dicho órgano. Objetivo: Caracterizar el factor de forma, perímetro, área y volumen de los núcleos de las células epiteliales glandulares mamarias. Métodos: Para caracterizar las glándulas mamarias sanas en mujeres de 60 años y más, se realizó un estudio de serie de casos en 14 mujeres fallecidas que no tenían lesiones benignas o malignas del órgano. Todas examinadas por el departamento de Anatomía Patológica del Hospital Provincial Vladimir Ilich Lenin en Holguín, en el período comprendido de septiembre 2018 a septiembre 2019. Para mejor valoración, la muestra de estudio se dividió en dos grupos de edades: de 60-75 años de edad y mayores de 75 años. Resultados: Tanto el factor de forma como el perímetro, área y volumen de los núcleos de las células epiteliales de los conductos mamarios son menores en las mujeres mayores de 75 años. Conclusiones: Existen diferencias notables en los indicadores morfométricos estudiados en ambos grupos de edades. Específicamente el tamaño y la forma de los núcleos de células epiteliales se ven afectados con la edad, lo cual se corresponde con la baja actividad metabólica de las células epiteliales mamarias en esta etapa de la vida.

Introduction: The mammary glands are organs that during the different stages of life in women undergo modifications, where the processes of proliferation, differentiation and apoptosis are involved, under hormonal control. However, once these hormonal influences cease, changes occur that lead to the involution of said organ. Objective: To determine the shape factor, perimeter, area and volume of the nuclei of glandular epithelial cells. Methods: To characterize healthy mammary glands in women aged 60 years and older, a case series study was conducted on 14 deceased women who had no benign or malignant lesions of the organ. All examined by the Department of Pathological Anatomy of the Provincial Hospital V.I. Lenin in Holguín, in the period between September, 2018 - September, 2019. For a better assessment, the study sample was divided into two age groups: from 60 to 75 years of age; age and older than 75 years. Results: Both the shape factor and the perimeter, area and volume of the nuclei of the epithelial cells of the mammary ducts are lower in women older than 75 years. Conclusions: There are notable differences in the morphometric indicators studied. Epithelial cell nuclei are affected with age, which corresponds to the low metabolic activity of mammary epithelial cells at this stage of life.

Indeterminate thyroid cytology: detecting malignancy using analysis of nuclear images.

BACKGROUND: Thyroid nodules diagnosed as 'atypia of undetermined significance/follicular lesion of undetermined significance' (AUS/FLUS) or 'follicular neoplasm/suspected follicular neoplasm' (FN/SFN), according to Bethesda's classification, represent a challenge in clinical practice. Computerized analysis of nuclear images (CANI) could be a useful tool for these cases. Our aim was to evaluate the ability of CANI to correctly classify AUS/FLUS and FN/SFN thyroid nodules for malignancy. METHODS: We studied 101 nodules cytologically classified as AUS/FLUS (n = 68) or FN/SFN (n = 33) from 97 thyroidectomy patients. Slides with cytological material were submitted for manual selection and analysis of the follicular cell nuclei for morphometric and texture parameters using ImageJ software. The histologically benign and malignant lesions were compared for such parameters which were then evaluated for the capacity to predict malignancy using the classification and regression trees gini model. The intraclass coefficient of correlation was used to evaluate method reproducibility. RESULTS: In AUS/FLUS nodule analysis, the benign and malignant nodules differed for entropy (P < 0.05), while the FN/SFN nodules differed for fractal analysis, coefficient of variation (CV) of roughness, and CV-entropy (P < 0.05). Considering the AUS/FLUS and FN/SFN nodules separately, it correctly classified 90.0 and 100.0% malignant nodules, with a correct global classification of 94.1 and 97%, respectively. We observed that reproducibility was substantially or nearly complete (0.61-0.93) in 10 of the 12 nuclear parameters evaluated. CONCLUSION: CANI demonstrated a high capacity for correctly classifying AUS/FLUS and FN/SFN thyroid nodules for malignancy. This could be a useful method to help increase diagnostic accuracy in the indeterminate thyroid cytology.

Follicular Lesions with Papillary Nuclear Characteristics: Differences in Chromatin Detected by Computerized Image Analysis.

OBJECTIVE: Follicular lesions of the thyroid with papillary carcinoma nuclear characteristics are classified as infiltrative follicular variant of papillary thyroid carcinoma-FVPTC (IFVPTC), encapsulated/well demarcated FVPTC with tumour capsular invasion (IEFVPTC), and the newly described category "non-invasive follicular thyroid neoplasm with papillary-like nuclear features" (NIFTP) formerly known as non-invasive encapsulated FVPTC. This study evaluated whether computerized image analysis can detect nuclear differences between these three tumour subtypes. METHODS: Slides with histological material from 15 cases of NIFTP and 33 cases of FVPTC subtypes (22 IEFVPTC, and 11 IFVPTC) were analyzed using the Image J image processing program. Tumour cells were compared for both nuclear morphometry and chromatin textural characteristics. RESULTS: Nuclei from NIFTP and IFVPTC tumours differed in terms of chromatin textural features (grey intensity): mean (92.37 ± 21.01 vs 72.99 ± 14.73, p = 0.02), median (84.93 ± 21.17 vs 65.18 ± 17.08, p = 0.02), standard deviation (47.77 ± 9.55 vs 39.39 ± 7.18; p = 0.02), and coefficient of variation of standard deviation (19.96 ± 4.01 vs 24.75 ± 3.31; p = 0.003). No differences were found in relation to IEFVPTC. CONCLUSION: Computerized image analysis revealed differences in nuclear texture between NIFTP and IFVPTC, but not for IEFVPTC.

Follicular Lesions with Papillary Nuclear Characteristics: Differences in Chromatin Detected by Computerized Image Analysis

ABSTRACT Objective: Follicular lesions of the thyroid with papillary carcinoma nuclear characteristics are classified as infiltrative follicular variant of papillary thyroid carcinoma-FVPTC (IFVPTC), encapsulated/well demarcated FVPTC with tumour capsular invasion (IEFVPTC), and the newly described category "non-invasive follicular thyroid neoplasm with papillary-like nuclear features" (NIFTP) formerly known as non-invasive encapsulated FVPTC. This study evaluated whether computerized image analysis can detect nuclear differences between these three tumour subtypes. Materials and methods: Slides with histological material from 15 cases of NIFTP and 33 cases of FVPTC subtypes (22 IEFVPTC, and 11 IFVPTC) were analyzed using the Image J image processing program. Tumour cells were compared for both nuclear morphometry and chromatin textural characteristics. Results: Nuclei from NIFTP and IFVPTC tumours differed in terms of chromatin textural features (grey intensity): mean (92.37 ± 21.01 vs 72.99 ± 14.73, p = 0.02), median (84.93 ± 21.17 vs 65.18 ± 17.08, p = 0.02), standard deviation (47.77 ± 9.55 vs 39.39 ± 7.18; p = 0.02), and coefficient of variation of standard deviation (19.96 ± 4.01 vs 24.75 ± 3.31; p = 0.003). No differences were found in relation to IEFVPTC. Conclusion: Computerized image analysis revealed differences in nuclear texture between NIFTP and IFVPTC, but not for IEFVPTC.

Simple Whole-Mount Staining Protocol of F-Actin for Studies of the Female Gametophyte in Agavoideae and Other Crassinucellate Ovules.

During plant sexual reproduction, F-actin takes part in the elongation of the pollen tube and the movement of sperm cells along with it. Moreover, F-actin is involved in the transport of sperm cells throughout the embryo sac when double fertilization occurs. Different techniques for analysis of F-actin in plant cells have been developed: from classical actin-immunolocalization in fixed tissues to genetically tagged actin with fluorescent proteins for live imaging of cells. Despite the implementation of live cell imaging tools, fixed plant tissue methods for cytoskeletal studies remain an essential tool for genetically intractable systems. Also, most of the work on live imaging of the cytoskeleton has been conducted on cells located on the plant's surface, such as epidermal cells, trichomes, and root hairs. In cells situated in the plant's interior, especially those from plant species with thicker organ systems, it is necessary to utilize conventional sectioning and permeabilization methods to allow the label access to the cytoskeleton. Studies about the role of F-actin cytoskeleton during double fertilization in plants with crassinucellate ovules (e.g., Agave, Yucca, Polianthes, Prochnyantes, and Manfreda) remain scarce due to the difficulties to access the female gametophyte. Here, we have developed a straightforward method for analysis of F-actin in the female gametophyte of different Agavoideae sub-family species. The procedure includes the fixation of whole ovules with formaldehyde, followed by membrane permeabilization with cold acetone, a prolonged staining step with rhodamine-phalloidin, and Hoechst 33342 as a counterstain and two final steps of dehydration of samples in increasing-concentration series of cold isopropanol and clarification of tissues with methyl salicylate. This technique allows the analysis of a large number of samples in a short period, cell positioning relative to neighbor cells is maintained, and, with the help of a confocal microscope, reconstruction of a single 3D image of F-actin structures into the embryo sac can be obtained.

Nuclear proteasomal degradation of Saccharomyces cerevisiae inorganic pyrophosphatase Ipp1p, a nucleocytoplasmic protein whose stability depends on its subcellular localization.

Inorganic pyrophosphate (PPi) is an abundant by-product of cellular metabolism. PPi-producing reactions take place in the nucleus concurrently with reactions that use PPi as a substrate. Saccharomyces cerevisiae possesses two soluble pyrophosphatases (sPPases): Ipp1p, an essential and allegedly cytosolic protein, and Ipp2p, a mitochondrial isoenzyme. However, no sPPase has yet been unambiguously described in the nucleus. In vivo studies with fluorescent fusions together with activity and immunodetection analyses demonstrated that Ipp1p is a nucleocytoplasmic protein. Mutagenesis analysis showed that this sPPase possesses a nuclear localization signal which participates in its nuclear targeting. Enforced nucleocytoplasmic targeting by fusion to heterologous nuclear import and export signals caused changes in polypeptide abundance and activity levels, indicating that Ipp1p is less stable in the nucleus that in the cytoplasm. Low nuclear levels of this sPPase are physiologically relevant and may be related to its catalytic activity, since cells expressing a functional nuclear-targeted chimaera showed impaired growth and reduced chronological lifespan, while a nuclear-targeted catalytically inactive protein was not degraded and accumulated in the nucleus. Moreover, nuclear proteasome inhibition stabilized Ipp1p whereas nuclear targeting promoted its ubiquitination and interaction with Ubp3p, a component of the ubiquitin-proteasome system. Overall, our results indicate that Ipp1p is nucleocytoplasmic, that its stability depends on its subcellular localization and that sPPase catalytic competence drives its nuclear degradation through the ubiquitin-proteasome system. This suggests a new scenario for PPi homeostasis where both nucleocytoplasmic transport and nuclear proteasome degradation of the sPPase should contribute to control nuclear levels of this ubiquitous metabolite.

Nuclear parameters and chromatin remodeling in epithelial cells and lymphocytes from the palpebral conjunctiva of dogs with keratoconjunctivitis sicca.

OBJECTIVE: To study parameters related to nuclear morphology and chromatin remodeling in epithelial cells and lymphocytes from the inferior palpebral conjunctiva of dogs with and without keratoconjunctivitis sicca (KCS). ANIMALS STUDIED: Thirty-two dogs (64 eyes) were included in the study. Based on the tear production measured by Schirmer tear test 1, the dogs were distributed into control and KCS groups. PROCEDURES: Epithelial cells and lymphocytes were collected by conjunctival brush cytology, fixed on glass slides, and subjected to the Feulgen reaction, a topochemical method specific for DNA/chromatin. Feulgen-stained cells were studied by microscopy and video image analysis to establish nuclear size (area and perimeter) and shape (relative nuclear roundness factor = RNRF), DNA content (ploidy), and compaction and texture of chromatin. RESULTS: Conjunctival samples in the KCS group showed infiltration of inflammatory and immune cells. Micronuclei, snake-like chromatin, aberrant chromosomes, and goblet cells were not detected. Compared with the controls, cells on the conjunctival surface of dogs with KCS showed altered nuclei. Conjunctival epithelial cells were more affected by KCS (changes in nuclear size, shape, DNA content, and chromatin compaction) than lymphocytes (changes in chromatin compaction, only). Significant chromatin decompaction was observed in both conjunctival epithelial cells and lymphocytes. CONCLUSIONS: Our results show that KCS promotes chromatin remodeling in epithelial cells and lymphocytes on the conjunctival surface of dogs. The changes described in this study are different from those reported for conjunctival cell nuclei of human KCS patients.

Follicular thyroid lesions: is there a discriminatory potential in the computerized nuclear analysis?

BACKGROUND: Computerized image analysis seems to represent a promising diagnostic possibility for thyroid tumors. Our aim was to evaluate the discriminatory diagnostic efficiency of computerized image analysis of cell nuclei from histological materials of follicular tumors. METHODS: We studied paraffin-embedded materials from 42 follicular adenomas (FA), 47 follicular variants of papillary carcinomas (FVPC) and 20 follicular carcinomas (FC) by the software ImageJ. Based on the nuclear morphometry and chromatin texture, the samples were classified as FA, FC or FVPC using the Classification and Regression Trees method. RESULTS: We observed high diagnostic sensitivity and specificity rates (FVPC: 89.4% and 100%; FC: 95.0% and 92.1%; FA: 90.5 and 95.5%, respectively). When the tumors were compared by pairs (FC vs FA, FVPC vs FA), 100% of the cases were classified correctly. CONCLUSION: The computerized image analysis of nuclear features showed to be a useful diagnostic support tool for the histological differentiation between follicular adenomas, follicular variants of papillary carcinomas and follicular carcinomas.

Herramienta alternativa para la clasificación de células cervicales utilizando solo rasgos del núcleo / Alternative tool for classification of cervical cells using only features of the nucleus

El cáncer de cérvix uterino representa una de las mayores amenazas de muerte por cáncer entre las mujeres. Con el avance continuo en la medicina y la tecnología, las muertes por esta enfermedad han disminuido significativamente. Las investigaciones referentes a este tema han podido determinar síntomas claves que permiten detectar a tiempo esta enfermedad para darle un tratamiento oportuno. La citología convencional es una de las técnicas más utilizadas, siendo ampliamente aceptada, de bajo costo, y con mecanismos de control. Con el objetivo de aliviar la carga de trabajo a los especialistas, algunos investigadores han propuesto el desarrollo de herramientas de visión computacional para detectar y clasificar las transformaciones en las células de la región del cuello uterino. La presente investigación tiene como objetivo proveer a los investigadores de una herramienta de clasificación automática, aplicable a las condiciones existentes en los centros médicos y de investigación del país. Esta herramienta debe ser capaz de clasificar las células del cuello del útero, basándose solamente en las características extraídas de la región del núcleo y sin utilizar las características del citoplasma, de manera que se reduzca la tasa de falsos negativos en la prueba de Papanicolaou. A partir del estudio realizado, se obtuvo una herramienta haciendo uso de la técnica k-vecinos más cercanos con la distancia manhattan, el cual mostró un alto desempeño manteniendo valores de AUC superiores al 91 por ciento y llegando hasta un 97.1 por ciento con respecto a los clasificadores SVM y RBF Network, los que también fueron analizados(AU)

Cervix cancer is one of the biggest threats of cancer death among women. With continued advances in medicine and technology, deaths from the disease have fallen significantly. The investigations concerning this issue have determined key symptoms to detect the disease in time to give timely treatment. Conventional cytology is one of the most widely used techniques, being widely accepted, inexpensive, and with control mechanisms. In order to alleviate the workload of specialists, some researchers have proposed the development of computer vision tools to detect and classify the changes in the cells of the cervical region. This research aims to provide a tool for automatic classification, applicable to medical conditions and research centers of the country. This tool should be able to classify the cells of the cervix, based solely on the features extracted from the core region without using the characteristics of the cytoplasm, so that the rate of false negative Pap test is reduced. From the study, a tool is obtained using the k nearest-neighbors manhattan distance technique, which showed a high performance maintaining AUC values greater than 91 percent and reaching 97.1 percent over classifiers SVM and RBF Network, which were also analyzed(AU)

Parámetros morfométricos de la mucosa en pacientes portadores de leucoplasia bucal con displasia epitelial / Morphometric parameters of the mucosa in patients that carry oral leukoplakia with epithelial dysplasia

Fundamento: la leucoplasia bucal es la lesión premaligna más frecuente, puede presentarse con displasia epitelial, que es el rasgo más importante de sus diversos cambios histopatológicos. Los métodos morfométricos y estereológicos permiten complementar el análisis histopatológico convencional de la displasia epitelial. Objetivo: caracterizar las lesiones de la mucosa con leucoplasia bucal según grado de displasia epitelial a través de indicadores morfométricos y estereológicos. Método: se realizó un estudio observacional descriptivo. El universo lo conformaron 68 biopsias de pacientes con diagnóstico clínico e histopatológico de leucoplasia y la muestra fue de 15 biopsias de leucoplasias displásicas, en las que se analizaron parámetros morfométricos y estereológicos. Resultados: se encontró que la altura de las crestas epiteliales y la altura del epitelio aumentan a medida que avanza el grado de la displasia epitelial. El valor promedio y su desviación estándar del factor de forma en la displasia ligera fue de 0,86 ± 0,08, en la displasia moderada fue de 0,88 ± 0,09 y en la displasia severa fue de 0,85 ± 0,11. El promedio y la desviación estándar del volumen nuclear y la densidad de perfiles nucleares epiteliales descienden al aumentar la displasia. Conclusiones: a partir del análisis de las variables analizadas en esta investigación podemos sugerir el estudio y la evaluación de la posibilidad de la existencia de algún modelo de relación volumen nuclear-perfiles nucleares-altura del epitelio como instrumento para determinar el comportamiento de la displasia.

Background: oral leukoplakia is the most frequent premalignant lesion; it can appear with epithelial dysplasia that is the most important feature of its various histopathological changes. Morphometric and stereological methods allow complementing the conventional histopathological analysis of epithelial dysplasia. Objective: to characterize the lesions of the mucosa with oral leukoplakia according to the degree of epithelial dysplasia through morphometric and stereological indicators. Method: a descriptive, observational study was conducted. The universe was composed of 68 biopsies from patients with a histopathological and clinical diagnosis of leukoplakia; the sample was composed of 15 biopsies from patients with dysplastic leukoplakias in which morphometric and stereological parameters were analyzed. Results: it was found that as the degree of epithelial dysplasia becomes greater, the more the height of the epithelial crest and the height of the epithelium rise. The average value and its standard deviation of the shape factor in minor dysplasia was of 0.86 ± 0.08, in moderate dysplasia was of 0.88 ± 0.09, and in serious dysplasia was of 0.85 ± 0.11. As the dysplasia becomes greater, the average and the standard deviation of the nuclear volume and the density of epithelial nuclear profile decrease. Conclusions: from the analysis of the variables through this investigation, we can suggest the study and evaluation of the possibility of the existence of a model of nuclear volume-nuclear profile-height of the epithelium relation, as an instrument to determine the behavior of dysplasia.

Estudio histomorfométrico del núcleo celular del carcinoma papilar de tiroides / Histomorphometric study of the cellular nucleus of the thyroid papillary carcinoma

Se realizó una evaluación morfométrica del carcinoma papilar tiroideo, con el objetivo de identificar posibles indicadores morfométricos que contribuyan a precisar su diagnóstico histológico. Se estudiaron 32 biopsias diagnosticadas en el Hospital Universitario “Celestino Hernández Robau”, de Santa Clara. Se determinaron las variables morfométricas nucleares: área, perímetro, radio y factor de forma, utilizando el programa de computación COMSDI PLUS versión 1.0. El carcinoma papilar en sus variantes hísticas no clásicas (folicular, oxífila y esclerosante difusa) presentaron valores más elevados del área, perímetro y radio nuclear, mientras que el carcinoma papilar, en su variante clásica, mostró un valor mayor de factor de forma. El estudio de correlación entre las variables estudiadas, en ambas variantes hísticas, no mostró similitud en sus resultados.

A morphometric evaluation of thyroid papillary carcinoma was carried out, with the objective of identifying possible morphometric parameters that contribute to precise its histological diagnosis. A number of 32 diagnosed biopsies of the University Hospital “Celestino Hernández Robau”, from Santa Clara were studied. Nuclear morphometric variables were determined, such as, area, perimeter, range and shape factor, by means of COMSDI PLUS version 1.0 computing program. Papillary carcinoma in its non classical histological variants (follicular, oxyphilic and diffuse sclerosing) showed more elevated values in area, perimeter and nuclear range, while, papillary carcinoma, in its classical variant, showed a high value in shape factor. The correlation study between studied variables did not showed similarity in its results in both histological variants.

Memantine prevents cardiomyocytes nuclear size reduction in the left ventricle of rats exposed to cold stress.

OBJECTIVES: Memantine is an N-methyl-d-aspartate (NMDA) glutamate receptor antagonist used to treat Alzheimer's disease. Previous studies have suggested that receptor blockers act as neuroprotective agents; however, no study has specifically investigated the impact that these drugs have on the heart. We sought to evaluate the effects of memantine on nuclear size reduction in cardiac cells exposed to cold stress. METHOD: We used male EPM-Wistar rats (n=40) divided into 4 groups: 1) Matched control (CON); 2) Memantine-treated rats (MEM); 3) Rats undergoing induced hypothermia (IH) and 4) Rats undergoing induced hypothermia that were also treated with memantine (IHM). Animals in the MEM and IHM groups were treated by oral gavage administration of 20 mg/kg/day memantine over an eight-day period. Animals in the IH and IHM groups were submitted to 4 hours of hypothermia in a controlled environment with a temperature of -8 degrees C on the last day of the study. RESULTS: The MEM group had the largest cardiomyocyte nuclear size (151 +/- 3.5 microm(3) vs. CON: 142 +/- 2.3 microm(3); p<0.05), while the IH group had the smallest mean value of nuclear size. The nuclear size of the IHM group was preserved (125 +/- 2.9 microm(3)) compared to the IH group (108 +/- 1.7 microm(3); p<0.05). CONCLUSION: Memantine prevented the nuclear size reduction of cardiomyocytes in rats exposed to cold stress.

Memantine prevents cardiomyocytes nuclear size reduction in the left ventricle of rats exposed to cold stress

OBJECTIVES: Memantine is an N-methyl-d-aspartate (NMDA) glutamate receptor antagonist used to treat Alzheimer's disease. Previous studies have suggested that receptor blockers act as neuroprotective agents; however, no study has specifically investigated the impact that these drugs have on the heart. We sought to evaluate the effects of memantine on nuclear size reduction in cardiac cells exposed to cold stress. METHOD: We used male EPM-Wistar rats (n=40) divided into 4 groups: 1) Matched control (CON); 2) Memantine-treated rats (MEM); 3) Rats undergoing induced hypothermia (IH) and 4) Rats undergoing induced hypothermia that were also treated with memantine (IHM). Animals in the MEM and IHM groups were treated by oral gavage administration of 20 mg/kg/day memantine over an eight-day period. Animals in the IH and IHM groups were submitted to 4 hours of hypothermia in a controlled environment with a temperature of - 8ºC on the last day of the study. RESULTS: The MEM group had the largest cardiomyocyte nuclear size (151 ± 3.5 μm³ vs. CON: 142 ± 2.3 μm³; p<0.05), while the IH group had the smallest mean value of nuclear size. The nuclear size of the IHM group was preserved (125 ± 2.9 μm³) compared to the IH group (108 ± 1.7 μm³; p<0.05). CONCLUSION: Memantine prevented the nuclear size reduction of cardiomyocytes in rats exposed to cold stress.

Cold stress effects on cardiomyocytes nuclear size in rats: light microscopic evaluation / Efeitos do estresse pelo frio sobre o tamanho nuclear do cardiomiócito em ratos: avaliação por microscopia de luz

INTRODUÇÃO: Hipotermia corporal induzida e resfriamento do miocárdio são métodos efetivos em relação à proteção domiocárdio durante cirurgias cardíacas e isquemia. É descrito na literatura que a exposição a temperaturas extremamente baixas causa comprometimentos de miofilamentos e de cristas mitocondriais em cardiomiócitos, entretanto, nenhum estudo analisou os efeitos do estresse pelo frio no tamanho do núcleo dos cardiomiócios. OBJETIVOS: Analisar os efeitos do estresse agudo pelo frio sobre o tamanho do núcleo dos cardiomiócitos. MÉTODOS: O estudo foi realizado em ratos Wistar adultos, pesando 300-310g (n=20). Os ratos foram divididos em dois grupos: 1) Controle (CON) e; 2) Hipotermia induzido (IH). Os animais do grupo IH foram expostos a uma temperatura controlada de -8ºC, durante 4 horas uma única vez. Foi realizada análise histológica de fígados e glândulas adrenais para examinar a condição de estresse. O tamanho do núcleo dos cardiomiócitos foi examinado por três investigadores independentes com o mesmo critério padronizado e posteriormente analisado pelo coeficiente de correlação de Bartko (R>0,75=concordância positiva). Teste t de Student foi aplicado. O nível de significância foi considerado como P<0,05. RESULTADOS: O grupo exposto ao estresse pelo frio apresentou maior depleção de lipídio nas glândulas adrenais (P<0,05) e de glicogênio no fígado (P<0,05). O grupo induzido à hipotermia mostrou menor volume do núcleo de seus cardiomiócitos (108 + 1,7 µm³; P<0,05), reduziu em 76 por cento comparado ao grupo controle (142 + 2,3 µm³). Correlação de Bartko: CON=0,44; IH=0,96, a variação entre a média dos grupos foi significativamente diferente. CONCLUSÃO: Esses resultados sugerem que a exposição ao estresse agudo pelo frio induz redução do núcleo dos cardiomiócitos em ratos.

INTRODUCTION: Total body induced hypothermia and myocardial cooling are effective methods regarding myocardial protection during heart surgery and ischemia. It is described in previous studies that extreme low temperature exposure causes mitochondrial cristae and myofilament disarrangement in cardiomyocytes, however, no investigation has analyzed the effects of cold stress on nuclear size of cardiomyocytes. OBJECTIVES: To evaluate the effects of acute cold stress exposure on the nuclear size of cardiomyocytes in rats. METHODS: The experimental study procedures were performed on 300-310g adult male Wistar rats. Rats (n=20) were divided into two groups: 1) Control (CON) and; 2) Induced hypothermic (IH) group. Animals of IH group were exposed during 4 hours once at a controlled temperature of - 8ºC. It was performed histological analysis of liver and adrenal gland to examine the stress condition of animals. Cardiomyocytes nucleus size were examined by three independent investigators with the same and standardized criteria and analyzed by Bartko's intra-class correlation coefficient (R>0.75 = positive concordance). Student's t test was applied. The significance level was set at P<0.05. RESULTS: The induced hypothermic group presented higher lipid depletion in adrenal gland cells (P<0.05) and higher glycogen depletion in liver glycogen (P<0.05). The experimental group showed lower cardiomyocytes nuclear volume (108 + 1.7 µm³; P<0.05), it decreased in 76 percent compared to the control group (142 + 2.3 µm³). Bartko's correlation: CON=0.44; IH=0.96, variation analysis between group's means differences was significant. CONCLUSION: These data suggest that acute cold stress exposure induces cardiomyocytes nucleus size reduction in rats.