RESUMO Introdução: Todos os anos são registados mais de 2,3 milhões de casos de cancro da mama, o que o torna o tipo cancro mais comum entre os adultos. A associação entre o cancro da mama e fatores ocupacionais é uma questão que tem vindo a ser estudada na literatura desde o início do século XVIII. Os desenvolvimentos tecnológicos permitiram um estudo mais aprofundado sobre a relação entre o cancro da mama e os fatores profissionais como a exposição a produtos químicos, pesticidas, metais e também fontes de exposição a radiação ionizante e não ionizante. O objetivo da presente revisão de literatura é incidir na relação entre a exposição ocupacional a radiação ionizante em trabalhadores da saúde e o desenvolvimento de cancro da mama. Metodologia: Foi efetuada uma pesquisa na Medline, com o motor de busca PubMed e na Elsevier, com o motor de busca Science Direct. As palavras de pesquisa usadas foram uma combinação dos termos breast cancer, occupational exposure, ionizing radiation e healthcare workers. Foi também realizada pesquisa na Revista Portuguesa de Saúde Ocupacional utilizando os termos “Cancro de mama” e “Radiação Ionizante”. Discussão/Conclusão: A literatura atual não é unânime quanto às características clínicas e patológicas específicas do cancro da mama possivelmente ligadas a contextos profissionais. Os profissionais de saúde, tais como técnicos de radiologia, enfermeiros, cirurgiões ortopédicos e cardiologistas de intervenção são especialmente vulneráveis a este tipo de exposição, nomeadamente à radiação ionizante. No entanto, alguns estudos apontaram para uma dificuldade em estabelecer uma relação causal entre estes fatores e o desenvolvimento de doença devido ao número de variáveis envolvidas, tais como a duração e intensidade da exposição e à influência de outros fatores de risco. As mudanças no equipamento, procedimentos e medidas de proteção resultaram em doses mais baixas nos anos mais recentes, o que significa que o risco de cancro da mama é baixo nos níveis atuais de exposição profissional à radiação ionizante.

ABSTRACT Introduction: Every year more than 2.3 million cases of breast cancer are registered, making it the most common type of cancer among adults. The association between breast cancer and occupational factors is an issue that has been studied in the literature since the beginning of the 18th century. Technological developments have allowed a more in-depth study of the relationship between breast cancer and occupational factors such as exposure to chemicals, pesticides, metals and also sources of exposure to ionising and non-ionising radiation.The aim of the present literature review is to complete an update on the scientific knowledge about the relationship between occupational exposure to ionising radiation in healthcare workers and the development of breast cancer. Methodology: A research was carried using Medline with the PubMed search engine and Elsevier with the Science Direct search engine. The search words used were a combination of breast cancer, occupational exposure, ionizing radiation and healthcare workers. A research was also carried out in Revista Portuguesa de Saúde Ocupacional, using the terms “Breast Cancer” and “Ionizing Radiation”. Discussion/Conclusions: Current literature is not unanimous about the specific clinical and pathological features of breast cancer possibly linked to occupational settings. Healthcare professionals such as radiology technicians, nurses, orthopaedic surgeons and interventional cardiologists are especially vulnerable to this type of exposure, particularly to ionising radiation. However, some studies have pointed to a difficulty in establishing a causal relationship between these factors due to the number of variables involved, such as the duration and intensity of exposure and the influence of other risk factors. Changes in equipment, procedures and protective measures have resulted in lower doses in recent years, which means that the risk of breast cancer is low at current levels of occupational exposure to ionizing radiation.

RESUMO Introdução: O setor da Saúde representa um grande desafio em Saúde Ocupacional, nomeadamente na prevenção e gestão das doenças profissionais. As patologias infeciosa, dermatológica, respiratória e musculosquelética representam a grande maioria das doenças profissionais na área da Saúde, sendo este último grupo o que se tem apresentado como mais prevalente em contexto hospitalar. Para além de consequências para a saúde dos trabalhadores, as doenças profissionais apresentam também elevados custos para as empresas e sociedade em geral. Objetivos: Análise das doenças profissionais participadas num Serviço de Saúde Ocupacional de um hospital terciário português. Métodos: Estudo observacional retrospetivo entre janeiro de 2011 e dezembro de 2022. Os dados foram obtidos do software do Serviço de Saúde Ocupacional. Resultados: Verificou-se a participação de 203 doenças profissionais, entre 2011 e 2022, sendo que a idade média foi de 47,1 anos. O ano 2020, foi o que obteve o maior número de notificações, num total de 71, assim como de confirmações das mesmas. 83,7% das suspeitas foram em indivíduos do sexo feminino, sendo igualmente mais prevalentes nestas (5,9%). Destes, 62,6% correspondem a trabalhadores com horário por turnos. Os assistentes operacionais contabilizam o maior número absoluto (36,9%), no entanto são os técnicos superiores de diagnostico de terapêutica que apresentam maior prevalência de participações (9,9%). As doenças mais participadas e certificadas foram as infeciosas, seguidas das musculosqueléticas, sendo estas as que mais geraram incapacidade (9,1%). Discussão e Conclusão: A participação de doenças profissionais aumentou ao longo dos anos, tendo sofrido um maior incremento em 2020 pelo contexto de pandemia SARS-COV-2, facto que fez com que as patologias infeciosas prevalecessem em relação às do foro musculo esquelético, as mais reportadas até então. A distribuição por sexo, idade e modalidade de horário estão de acordo com a distribuição da população da organização. O maior número de notificações ocorreu nos assistentes operacionais, no entanto a sua prevalência foi maior nos técnicos de diagnóstico e terapêutica. Isto pode dever-se ao facto de no hospital em estudo estar integrado um centro de reabilitação, com mais técnicos, tais como fisioterapeutas, que prestam cuidados a doentes mais dependentes. Este estudo permite um melhor conhecimento da realidade em matéria de doenças profissionais no setor da saúde, permitindo assim o desenvolvimento de medidas preventivas, promovendo ambientes de trabalho mais saudáveis.

ABSTRACT Introduction: The health sector represents a major challenge regarding occupational health, particularly in terms of preventing and managing occupational diseases. Infectious, dermatological, respiratory and musculoskeletal diseases are the vast majority of occupational diseases in this sector, with the latter group being the most prevalent in hospitals. In addition to the consequences for workers' health, these diseases also have high costs for companies and society in general. Aims: Analysis of occupational diseases reported in a Occupational Health Service of a Portuguese tertiary hospital. Methods: Retrospective observational study between January 2011 and December 2022. The data was obtained from the Occupational Health Service software. Results: Between 2011 and 2022, 203 occupational diseases were notified, and the average age was 47,1 years. The year with the highest number of reports, was 2020, with a total of 71, and it was the year with the highest number of characterized diseases. Of all diseases reported, 83,7% were among female professionals, and they were also more prevalent among women (5,9%). 62,6% corresponded to shift workers. Healthcare assistants accounted for the largest absolute number of notifications (36,9%), but it was diagnostic and therapeutic technicians who had the highest prevalence (9,9%). The most reported and certified diseases were infectious, followed by musculoskeletal, which generated more disability (9,1%). Discussion and Conclusion: The number of occupational diseases has increased over the years, with a greater evolution in 2020 due to the SARS-COV-2 pandemic, which meant that infectious diseases prevailed over musculoskeletal ones, which had been the most prevalent until then. The distribution by gender, age and working hours is in line with the distribution of the organization’s population. The highest number of notifications occurred among healthcare assistants, but its prevalence was higher among diagnostic and therapeutic technicians. This may be because the hospital under study includes a rehabilitation center with more technicians, such as physiotherapists, who provide care to more dependent patients. This study provides a better understanding of the reality of occupational diseases in the health sector, thus allowing the development of preventive measures and promoting healthier working environments.

ABSTRACT Introduction Healthcare professionals are exposed to a multitude of occupational risks that can lead to work-related injuries, resulting in implications both at the hospital management level and community level. For the development of a preventive safety culture, it is essential to analyze the causes that lead to their occurrence. This study is a descriptive and analytical analysis of the work-related injuries that occurred in a hospital unit, characterizing them and relating them to occupational risks. The target population of the study consists of healthcare workers from a tertiary hospital in the north of Portugal. Aims Analysis of the work-related injuries recorded by the Occupational Health Service in a Portuguese tertiary hospital. Methods Retrospective observational study between January 2017 and December 2022. Data were obtained from the Occupational Health Service software. Results A total of 1279 work-related injuries were recorded from 2017 to 2022, of which 93,8% took place in the facilities of the Hospital Center. Most of them (82,8%) occurred in female workers. A higher number of work-related injuries was observed among healthcare assistants (43.2%) and nurses (35.5%). The mechanical risk was found to have the highest incidence (46,4%), followed by biological (26,3%) and ergonomic (22,4%) risks. The upper limb (46,3%) and lower limb (22,4%) were the anatomical regions most affected by the accidents. Most of the lost days resulting from work-related injuries were in the range of 3 to 30 days (58,8%). Discussion and Conclusion Work-related injuries presented a variable distribution throughout the studied period and most of these took place within the Hospital Center. The mechanical risk, which is essentially responsible for musculoskeletal injuries, was the leading cause of injury, followed by biological risk, in accordance with the literature. There was a significant increase in the number of work-related injuries related to psychosocial risks, which is directly related to violent behaviors against hospital staff making it urgent to develop preventive measures in this area. Due to the morbidity caused and the consequent absenteeism, work-related injuries contributed to a significant loss of productivity. Therefore, it is essential to keep investing in preventive policies and improvement of the work conditions in the healthcare sector.

RESUMO Introdução Os profissionais de saúde estão expostos a uma multiplicidade de riscos ocupacionais que podem culminar na ocorrência de acidentes de trabalho, originando implicações quer a nível da gestão hospitalar, quer a nível comunitário. Para o desenvolvimento de uma cultura de segurança preventiva, torna-se fundamental analisar as causas que levam à sua ocorrência. O presente trabalho é um estudo descritivo e analítico sobre os acidentes de trabalho ocorridos numa unidade hospitalar, caracterizando-os e relacionando-os com os riscos profissionais. A população alvo do estudo é constituída pelos profissionais de um hospital terciário do norte de Portugal. Objetivos Análise dos Acidentes de Trabalho registados pelo Serviço de Saúde Ocupacional num hospital terciário português. Métodos Trata-se de um estudo observacional retrospetivo entre janeiro de 2017 e dezembro de 2022. Os dados foram obtidos do software do Serviço de Saúde Ocupacional. Resultados Verificaram-se 1279 acidentes de trabalho no período referido de seis anos, sendo que 93,8% ocorreram nas instalações do Centro Hospitalar. Do total de acidentes de trabalho, 82,8% dizem respeito a trabalhadores do sexo feminino. Registou-se maior número de acidentes de trabalho nos assistentes operacionais (43,2%) e enfermeiros (35,5%). O risco mecânico foi onde se encontrou maior incidência (46,4%), seguido do biológico (26,3%) e ergonómico (22,4%). O membro superior (46,3%) e inferior (22,4%) foram as regiões anatómicas mais afetadas. Maioritariamente os dias perdidos resultantes dos acidentes de trabalho encontram-se no intervalo de três a 30 dias (58,8%). Discussão e Conclusão Os acidentes de trabalho apresentaram uma distribuição variável ao longo do período estudado e a maioria destes ocorreu nas instalações do Centro Hospitalar. O risco mecânico, associado às lesões musculoesqueléticas, foi o que originou mais acidentes de trabalho, seguindo-se o risco biológico, estando de acordo com a literatura. Ao longo do período estudado é possível constatar um aumento significativo do número de acidentes de trabalho relacionados com o risco psicossocial, estando estes diretamente relacionados com agressões a profissionais do Centro Hospitalar, sendo assim urgente desenvolver medidas preventivas nesta matéria. Os acidentes de trabalho, pela morbilidade causada e consequente absentismo originado, contribuíram para uma importante perda de produtividade, sendo assim fundamental continuar a investir em políticas preventivas e de melhoria das condições de trabalho no setor na Saúde.

Abstract This study examines the in vitro growth and ex vitro establishment of Brassavola tuberculata in relation to the micropropagation system and sucrose concentration employed in the in vitro culture. A completely randomized experimental design was utilized, employing a 2 x 5 factorial arrangement. The experimental period began with seedlings cultivated in vitro for 180 days, which were subsequently transferred to Murashige and Skoog culture media containing sucrose concentrations of 0, 15, 30, 45, or 60 g L-1. The cultures were subjected to two micropropagation systems: conventional and gas exchange. After 90 days of in vitro cultivation, the plants were evaluated, transplanted into a substrate, and placed in a screened nursery for ex vitro cultivation. After 300 days of ex vitro cultivation, the survival and initial characteristics of the plants were assessed. The micropropagation system allowing gas exchange and sucrose concentrations up to 30 g L-1 enhanced the shoot and root growth of in vitro propagated plants. No noticeable anatomical differences were observed after 90 days of in vitro culture among the different sucrose concentrations and micropropagation systems used. In the ex vitro establishment, irrespective of sucrose concentration, the micropropagation system facilitating gas exchange positively influenced all evaluated characteristics.

Resumo Objetivou-se com este trabalho avaliar o crescimento in vitro e estabelecimento ex vitro de Brassavola tuberculata em função do sistema de micropropagação e da concentração de sacarose utilizados no cultivo in vitro. Foi utilizado o delineamento inteiramente casualizado e os tratamentos arranjados em esquema fatorial 2 x 5. Para o início do período experimental, foram utilizadas plântulas cultivadas in vitro por 180 dias, sendo transferidas para meios de cultivo Murashige e Skoog contendo 0, 15, 30, 45 ou 60 g L-1 de sacarose, e as culturas submetidas a dois sistemas de micropropagação: convencional ou com troca gasosa. Após 90 dias de cultivo in vitro, as plantas foram avaliadas e na sequência plantadas em substrato e acondicionadas em viveiro telado para o cultivo ex vitro. Após 300 dias de cultivo ex vitro, as plantas foram avaliadas quanto à sobrevivência e às mesmas características iniciais. A utilização do sistema de micropropagação que permite trocas gasosas, em conjunto com concentrações de sacarose de até 30 g L-1, proporcionou aumento no crescimento de parte aérea e do sistema radicular das plantas propagadas in vitro. As diferentes concentrações de sacarose e os sistemas de micropropagação utilizados não apresentaram diferenças anatômicas perceptíveis aos 90 dias de cultivo in vitro. Já no estabelecimento ex vitro, independente da utilização de sacarose, o sistema de micropropagação que permite trocas gasosas influenciou positivamente todas as características avaliadas.

RESUMEN This article presents the case report of a giant lateral dermoid cyst in the floor of mouth surgically excised by intraoral approach, initially misdiagnosed by imaging studies as a ranula. Other cases of dermoid cysts preoperatively diagnosed ranulae are present in literature, but none directly compares their clinical, radiological and therapeutic aspects. This article will also discuss these aspects in order to possibly aid in their correct diagnosis and management.

ABSTRACT Este artículo presenta el caso clínico de un gran quiste dermoide lateral en el suelo de la boca, extirpado quirúrgicamente por abordaje intraoral, inicialmente diagnosticado erróneamente por estudios de imagen como una ránula. Otros casos de quistes dermoides diagnosticados preoperatoriamente como una ránula están presentes en la literatura, pero ninguno compara directamente sus aspectos clínicos, radiológicos y terapéuticos. Este artículo también tratará estos aspectos para, posiblemente, ayudarles en su diagnóstico y manejo correctos.

Pyrometallurgical smelters consume significant amounts of fossil fuels. Notwithstanding emission abatement technologies, these smelters emit various gaseous pollutants and fine particulate matter, which are important from an air quality perspective. Additionally, carbon dioxide (CO2) and black carbon (BC), the two most important atmospheric climate forcing species, are also emitted. It is important to model the contribution, transport, and impact of pollutants emitted by pyrometallurgical smelters. In order to do this, atmospheric modellers require an accurate emission inventory, which indicates emissions (how much of what species by which processes), emission periods, stack/emission heights, and emission velocities (if emitted through stacks). However, in many countries atmospheric modellers do not have access to a proper emission inventory, or they are legally prohibited from obtaining such information. The current paper demonstrates how fire radiative power (FRP) observations by the Moderate Resolution Imaging Spectro-radiometer (MODIS) instruments on board the Aqua and Terra satellites can be used to estimate the availabilities of pyrometallurgical smelters. Such temporal activity patterns will assist modellers to re-create air quality scenarios for regions more accurately.

ABSTRACT This work studied the enzymatic hydrolysis of sugarcane bagasse aiming at the production of glucose and xylose. The bagasse was subjected to two different pretreatments: combined acid and alkalinepretreatment and hydrogen peroxidepretreatment. The enzymatic hydrolysis was optimized and a kinetic study was carried out in a stirred tank reactor (STR) in batch mode. Optimal conditions were obtained by subjecting the bagasse to the hydrogen peroxide pretreatment followed by enzymatic hydrolysis. The addition of xylanases to the enzymatic mixture improved the production of fermentable sugars by 48%.

Torch ginger Etlingera elatior (Jack) R.M. Smith is a tropical herb-like, rhizome-like and perennial plant that possesses inflorescences that are both pretty and showy at different colour shades, and have a great visual appeal. Producing seedlings at a high enough level when done conventionally by the division of tussocks, has high costs and phytosanitary problems. The objective of this study was to evaluate the induction of somatic embryogenesis and its potential for subsequent plant regeneration in torch ginger. Rhizomes, leaves and roots from the seedlings grown in vitro were used as explant segments. The different explants were cultured on MS medium supplemented with 30 g L-1 sucrose, and it was solidified with 5.5 g L-1 of agar. The effect of 2.4-D and picloram concentrations of 0.0, 1.0, 2.0 and 4.0 mg L-1 was studied. Astructural analysis was performed by scanning electron microscopy (SEM). Cytochemical analysis were performed to detect nucleeous with carmine acetic, starch with lugol and lipids with Sudan III, and a flow cytometry analysis to verify the stability of ploidy in the callus. Results indicate that the culture medium with 2.4-D yielded the induction of embryogenic callus with the characteristics of the rhizome segments of the explant. Regarding the ultrastructural analysis of embryogenic callus characteristics, the cells showed a similar isodiametric form as somatic embryos in the globular stage and cytochemical analysis. The presence of callus cells in pro-embryogenic explants containing each of the regulators was confirmed. In the cytometry analysis, the average DNA content of callus ranged from 5.43 to 10.15 pg, and the coefficients of variation varied between 0.3 to 2.26. Callus induced with 2.4-D showed 86 % stability, and with picloram was 64 %. The callus formation was more evident after application of 2.4 D. This is the first study of embryogenic potential in cells of the torch ginger, and showed that 2,4-D induced callus with higher starch content and genetically stable.

El jengibre antorcha Etlingera elatior (Jack) R. M. Smith es una planta tropical perenne, similar al rizoma, que tiene inflorescencias que son bellas y llamativas, de diferentes colores y matices y de un gran atractivo visual. La producción de plántulas en un nivel lo suficientemente alto cuando se hace convencionalmente utilizando la división de matas tiene altos costos y problemas fitosanitarios. El objetivo de este estudio fue evaluar la inducción de la embriogénesis somática y su uso potencial para la reproducción posterior de plantas de jengibre antorcha. Los rizomas, hojas y raíces de las plántulas cultivadas in vitro se utilizaron como segmentos de explantes. Los diferentes explantes se cultivaron en un medio MS al que se le agregaron 30 g L-1 de sacarosa y fue solidificado con 5.5 g de agar L-1. Se estudió el efecto del 2.4-D y picloram en concentraciones de 0.0, 1.0, 2.0 y 4.0 mg L-1. El análisis estructural se llevó a cabo por microscopía electrónica de barrido (SEM). Se realizaron análisis citoquímicos para detectar núcleos con carmín acético, almidón con lugol y lípidos con Sudán III; y un análisis de citometría de flujo para verificar la estabilidad de la ploidía en el callo. Los resultados indicaron que el medio de cultivo con 2.4-D produjo la inducción de callo embriogénico con las características de los segmentos de rizomas del explante. En el análisis ultraestructural de las características del callo embriogénico, las células mostraron una forma isodiamétrica similar a embriones somáticos en etapa globular y análisis citoquímico. Se confirmó la presencia de células de callo en explantes pro- embriogénicos conteniendo cada uno de los reguladores. En el análisis de citometría, el contenido medio de ADN del callo varió de 5.43 a 10.15 pg, y los coeficientes de variación oscilaron entre 0.3 y 2.26. El 2.4-D indujo callos con estabilidad de 86 %, y con picloram fue 64 %. La formación de callo fue más evidente después de aplicar 2.4-D. Éste es el primer estudio del potencial embriogénico de células del jengibre antorcha, y mostró que el 2.4-D indujo la formación de callo con mayor contenido de almidón y genéticamente estable.

The structural alterations that occur in the muscle fibers of denervated rat diaphragms were studied. Fifteen adult male albino rats (Rattus norvegicus) with a mean weight of 200 g and about 60 days of age were used. Chronically denervated diaphragms were obtained and the animals were sacrificed after 4, 8 and 12 weeks of denervation. The left antimere of the diaphragm was denervated by sectioning of the phrenic nerve and the right antimere served as control. Each antimere was divided into fragments, which were used for analysis transmission electron microscopy. During the initial phase of denervation (4 weeks), ultrastructural muscle modifications appeared in scattered fibers and in foci along these fibers. Muscle fibers with foci of less dense and loosely arranged myofibrils, disorganized Z line, displaced T tubules, and central nucleus exhibiting reentrances and fragmented aspect were observed. After 8 weeks, formation of large aggregates of small elongated mitochondria showing altered cristae, matrix inclusions and increased electron density was noted. At 12 weeks of denervation the alterations were found to be more drastic. Nuclei with internal deposits of myofibrillar or amorphous material were observed. In these fibers, vacuoles harbored enormous myeloid structures in the subsarcolemmal or intermyofibrillar region.

Fueron estudiadas las alteraciones ultra estructurales de las fibras musculares del diafragma denervado de ratas. Fueron utilizadas 15 ratas albinas (Rattus norvegicus), machos, adultas, con peso promedio de 200 g de aproximadamente 60 días de edad. Los diafragmas crónicamente denervados fueron obtenidos después de 4, 8 y 12 semanas de denervación. El antímero izquierdo del diafragma fue denervado por sección del nervio frénico y el antímero derecho fue utilizado como control. Cada antímero fue dividido en fragmentos, que fueron utilizados para el estudio en microscopia electrónica de transmisión. Durante los períodos iniciales de denervación (4 semanas), las modificaciones en la ultraestructura del músculo se disponen en fibras dispersas y en focos a lo largo de las mismas. Se observan fibras musculares con focos de miofibrillas rarefactas y laxamente dispuestas; línea Z desorganizada; túbulos T dislocados; núcleo central con aspecto fragmentado. Después de 8 semanas de denervación, se observa la formación de numeroso agregados de pequeñas mitocondrias alargadas, con alteraciones en las crestas, inclusiones en la matriz y aumento de la electrodensidad. Con 12 semanas de denervación, las alteraciones se muestran más drásticas; se observan núcleos con depósitos internos de material miofibrillar o amorfo. En estas fibras, las vacuolas presentan grandes estructuras mieloides en la región subsarcolemal o intermiofibrillar.

The morphological alterations that occur in the muscle fibers of denervated rat diaphragms were studied. Fifteen adult male albino rats (Rattus norvegicus) with a mean weight of 200 g and about 60 days of age were used. Chronically denervated diaphragms were obtained and the animals were sacrificed after 4, 8 and 12 weeks of denervation. The left antimere of the diaphragm was denervated by sectioning of the phrenic nerve and the right antimere served as control. Each antimere was divided into two fragments, which were used for histological (H.E.) and histoenzymological (NADH-TR and myofibrillar ATPase). After 4 weeks, denervated muscle fibers showed important light microscopic alterations: atrophy with angular profiles in cross-sections, cytoplasm containing vacuoles, enlarged interstitial space with increased connective tissue, cellular infiltration, and muscle fibers without defined contours. The most marked alterations being observed for type IIb and IIa fibers. Eight and 12 weeks after denervation, the NADH-TR reaction showed that it was impossible to characterize the muscle fibers based on their metabolic profile.

Fueron estudiadas las alteraciones morfológicas de las fibras musculares del diafragma denervado de ratas. Se utilizaron 15 ratas albinas (Rattus norvegicus) machos, adultos, con peso promedio de 200g y cerca de 60 días de edad. Se denervó el diafragma y después de 4, 8 y 12 semanas los animales fueron sacrificados. El antímero izquierdo del diafragma fue denervado por sección del nervio frénico y el antímero derecho fue utilizado como control. Cada antímero fue dividido en fragmentos, utilizados para el estudio histológico (H-E), histoenzimológico (NADH-TR y ATPasa miofibrilar). Después de 4 semanas las fibras musculares denervadas presentaron alteraciones importantes en lamicroscopía de luz: atrofia con perfiles angulados en secciones transversales; citoplasma con vacuolas; aumento del espacio intersticial con aumento de tejido conjuntivo; infiltración celular y fibras musculares sin contornos definidos, siendo las alteraciones más marcadas en las fibras tipo IIb e IIa. Después de 8 y 12 semanas de denervación la reacción para NADH-TR demuestra que es imposible caracterizar a las fibras musculares a través de su perfil metabólico.

The morphological and structural alterations that occur in the neuromuscular junctions of the denervated rat diaphragm were studied. Fifteen adult male albino rats (Rattus norvegicus) aged about 60 days and with a mean weight of 200 g were used. Chronically denervated diaphragms were obtained and the animals were sacrificed after 4, 8 and 12 weeks of denervation. The left antimere of the diaphragm was denervated by section of the phrenic nerve and the right antimere was used as control. Each antimere was divided into three fragments: one was used for histochemical (nonspecific esterase) and morphometric study of neuromuscular junctions, and the other two were used for transmission and scanning electron microscopy (SEM) analysis. Histochemical analysis of the diaphragm neuromuscular junctions after denervation showed only small changes in junction morphology. However, these junctions became smaller and elongated and presented less visible contours with increasing time of denervation. Ultrastructural analysis of neuromuscular junctions after 12 weeks showed more or less organized junctional folds on the muscle fiber surface. The junctional cytoplasm exhibited important alterations such as mitochondrial degeneration and the presence of numerous filaments. SEM revealed the presence of deep primary synaptic grooves with peripheral excavations which housed the nerve terminal boutons and exhibited internally the secondary synaptic clefts present among the junctional folds of the sarcolemma. This study showed that some of the morphological changes demonstrated in other denervated striated skeletal muscles are not repeated at the same intensity or in the same temporal pattern in the rat diaphragm.

En este trabajo se estudiaron las alteraciones morfológicas y estructurales de las uniones neuromusculares en el diafragma denervado de ratas. Se utilizaron 15 ratas albinas (Rattus norvegicus), machos, adultos, con peso promedio de 200g y cerca de 60 días de edad. Los diafragmas crónicamente denervados fueron obtenidos y los animales se sacrificaron después de 4, 8 y 12 semanas de denervación. El antímero izquierdo del diafragma fue denervado por sección del nervio frénico y el antímero derecho fue utilizado como control. Cada antímero fue dividido en 3 fragmentos: uno fue utilizado para el estudio histoquímico (esterasa inespecífica) y morfométrico. Los otros dos se destinaron al estudio de microscopía electrónica de transmisión (MET) y microscopia electrónica de barrido (MEB) de las uniones neuromusculares. El estudio histoquímico de las uniones neuromusculares posterior a la denervación, muestra que la morfología de esas uniones sufre pequeñas alteraciones. Con la evolución del tiempo de denervación esas uniones muestran tamaños menores, son alargadas y con contornos menos nítidos. La ultra-estructura de las uniones neuromusculares después de 12 semanas, demostró que la superficie de la fibra muscular exhibe pliegues de unión más o menos organizados. La región del citoplasma de unión exhibe alteraciones importantes, con degeneración mitocondrial y presencia de muchos filamentos. En MEB se observa que los botones sinápticos primarios son profundos, presentan escavaciones periféricas donde estaban alojados los botones de las terminaciones nerviosas y exhiben internamente, los espacios sinápticos secundarios presentes entre los pliegues de unión del sarcolema. Este estudio mostró que algunos patrones morfológicos demostrados en otros músculos estriados esqueléticos denervados no se repiten con la misma intensidad y curso temporal en el diafragma de ratas.