Anatomy of the lymphatic drainage of the upper limb and breast and its role in lymphedema prevention after breast cancer treatment / Anatomía del drenaje linfático del miembro superior y de la mama y su papel en la prevención del linfedema después del tratamiento del cáncer de mama

The surgical treatment of breast cancer has been enhanced throughout the years in order to offer oncologically safer and more effective results with lower esthetic impact and fewer sequelae. The lymphedema of the upper limb is still an iatrogenic result of great incidence and morbidity after this treatment. A possible existence of independent breast and upper limb lymphatic pathways has become the issue of many researchers willing to minimize its occurrence. This review aims to compare the lymphatic pathways in the axilla described by traditional anatomy books and recently published articles about Axillary Reverse Mapping (ARM). With this purpose, a comparative table was made with the descriptions found in books and articles, a statistic table of the data collected, a flowchart of anastomoses among nodes and an analytical drawing of the most statistically mentioned drained areas. It was observed that there is great variability in the descriptions of drainage and anastomoses among the lymph nodes in the references used, so there should be a consensus of a universal description which also assembles possible anatomical variations. Furthermore, the findings brought about by recent studies show possible anastomoses among pathways and lymph nodes, however they have not been taken into consideration when ARM was initially proposed. Therefore, the axillary resection with the preservation of the posterior and lateral axillary lymph nodes is theoretically possible to avoid lymphedema of the upper limb, but the development of an updated universal description that involves all possible anatomical variations will provide a safer and more effective treatment.

El tratamiento quirúrgico del cáncer de mama ha mejorado a lo largo de los años con el fin de ofrecer resultados oncológicamente más seguros y eficaces con menor impacto estético y menos secuelas. El linfedema del miembro superior es todavía un resultado iatrogénico de gran incidencia y morbilidad después de este tratamiento. La posible existencia de vías linfáticas de mama y de los miembros superiores independientes se ha convertido en un tema central de muchas investigaciones para lograr minimizar su ocurrencia. Esta revisión tiene como objetivo comparar las vías linfáticas en la axila descritas en los libros de anatomía tradicionales con artículos recientemente publicados sobre Mapeo Reverso Axilar (MRA). Con este fin, se realizó un cuadro comparativo con las descripciones y un diagrama de flujo de las anastomosis entre los nodos, además de un dibujo analítico de las áreas drenadas estadísticamente más mencionadas. Se observó que existe una gran variabilidad en las descripciones sobre el drenaje y las anastomosis entre los nodos linfáticos, por lo que la descripción universal no debería ser considerada un consenso debido a que también presenta posibles variaciones anatómicas. Por otra parte, los resultados producidos por los estudios recientes muestran posibles anastomosis entre las vías y los nodos linfáticos, sin embargo, no se han tomado en consideración cuando se propuso inicialmente el MRA. Por lo tanto, la resección axilar con la preservación de la parte posterior y los nodos linfáticos axilares laterales es teóricamente posible para evitar el linfedema del miembro superior, pero el desarrollo de una descripción universal actualizada, que incluya todas las posibles variaciones anatómicas, proporcionará un tratamiento más seguro y eficaz.

Effects of plyometric training on explosive strength, acceleration capacity and kicking speed in young elite soccer players.

AIM: The main aim of this study was to determine the effects of a 10-week plyometric training program on explosive strength, acceleration capacity and kicking speed in young elite soccer players. METHODS: Twenty-two players participated in the study: control group (CG), (N.=11; 18.2 ± 0.9 years) and treatment group (TG) (N.=11; 18.4 ± 1.1 years). Both groups performed technical and tactical training exercises and matches together. However, the CG players followed the regular physical conditioning program, which was replaced by a plyometric program for TG. Plyometric training took place three days a week and included jumps over hurdles, horizontal jumps and lateral jumps over hurdles. Jumping ability, 10 m sprint and kicking speed were measured on five separate occasions. RESULTS: Two-way analysis of variance (ANOVA) with repeated measures reflected that the TG demonstrated significant increases (P<0.05) in jumping ability and acceleration capacity after six weeks of training and in kicking speed with dominant and non-dominant leg after eight and ten weeks respectively. On the other hand there were no significant changes in CG players throughout the study. CONCLUSION: The main findings revealed that a 10-week plyometric program may be an effective training stimulus to improve explosive strength compared to a more conventional physical training program. The improvements in explosive strength can be transferred to acceleration capacity and kicking speed but players need time to transfer these increases.

Anthropometric and anaerobic fitness profile of elite and non-elite female soccer players.

AIM: The main aim of the current study was to compare the anthropometrical and fitness profile of female soccer players by level and by playing positions. The second purpose was to explore correlations between kicking speed on the one hand and anthropometric features and explosive strength on the other. METHODS: Female soccer players (N.=190) were tested divided in two groups: elite group (N.=100) and non-elite group (N.=90). Body mass, height, leg length, body composition, counter movement jump, drop jump and kicking speed with both legs were measured. RESULTS: After controlling for experience with multivariate analysis of covariance (MANCOVA), body mass, body fat and muscle mass differed significantly by level. MANCOVA also revealed that all the anthropometrical variables differed by playing position. However, MANCOVA did not show significant differences by level of play, neither for explosive strength nor for kicking speed but revealed significant differences among playing positions. There were significant positive correlations between body mass, height, leg length, muscle mass, counter movement jump height, drop jump height and experience on the one hand and kicking speed with dominant and non-dominant leg on the other for the elite and non-elite players. CONCLUSIONS: Elite players differ from their non-elite counterparts in terms of anthropometrical features, while explosive strength and kicking speed are not sensitive enough to distinguish between levels. On the other hand, the findings indicate few positional variations, and only goalkeepers, tend to have a specific anthropometric and fitness profile. Anthropometric variables, explosive strength and experience have an influence on kicking speed.

Unidad de enfermedad renal crónica avanzada (ERCA).Concepto de una unidad multidisciplinaria. Objetivos de la consulta de ERCA / No disponible

• Un asistencia óptima en la fase de ERC avanzada (ERCA),antes del inicio de la diálisis, debe contemplar:– detección precoz de la enfermedad renal progresiva,– intervenciones para retardar su progresión– prevenir las complicaciones urémicas– atenuar las condiciones comórbidas asociadas– adecuar la preparación para el TRS e iniciarlo en el momento adecuado de forma programada.– La alternativa de futuro son los equipos multidisciplinarios(EMD) de manejo de la ERC avanzada y deberá de disponer de recursos humanos y materiales especificos (AU)

• Optimal care of patients with advanced CKD (ACKD) before the initiation of dialysis should include:– Early detection of progressive kidney disease– Interventions to delay its progression– Prevention of uremic complications– Reduction of associated comorbid conditions– Appropriate preparation and scheduled initiation of KRT.– Multidisciplinary teams (MDT) are the future alternative for management of advanced CKD and they should have specific human and material resources (AU)

Guía de nutrición en Enfermedad Renal Crónica Avanzada (ERCA) / No disponible

• La prescripción de la ingesta proteica en ERC es compleja por los conflictos potenciales existentes para retrasarla progresión de la ERC y preservar el estado nutricional. Proporcionar alrededor de 0,75 g proteínas/ kg/ día parece razonable en pacientes con FG > 30 mL (ERC estadios1-3). En estadios 4, 5 es recomendable proporcionar alrededor de 0,6 g/kg/día. Para frenar la progresión y minimizar la acumulación de toxinas urémicas.• Mantener una adecuada ingesta energética es esencial en todos los estadios de ERC.• La valoración del estado nutricional en ERC requiere de la utilización de múltiples marcadores, para valorar el estatus proteico, los depósitos de grasa, la composición corporal y la ingesta energética y proteica.• La Malnutrición Proteico Energética (MPE) puede ser considerada como una indicación para el inicio en terapia renal sustitutiva. Si la MPE se desarrolla o persiste a pesar de intentar optimizar la ingesta y no existe otra causa de malnutrición que la ingesta o anorexia urémica está indicada la iniciación de diálisis o el trasplante renal en pacientes con FG > 15 mL/ min.• El tratamiento nutricional para pacientes con ERC debería incluir valoración nutricional, educación y una planificación y seguimiento nutricional (AU)

• Prescription of protein intake in CKD is complicated by potential conflicts between goals to delay progression of CKD and preserve nutritional status. Providing a protein intake of about 0.75 g/kg/day appears reasonable in patients with GRF > 30 mL (CKD stages 1-3). In CKD stage 4 and 5, it is recommended to provide a protein intake of about0.6 g/kg/day to slow progression and minimize accumulation of uremic toxins.• Maintaining adequate energy intake is essential in all stages of CKD.• Assessment of nutritional status in CKD requires multiple markers to assess protein status, fat stores, body composition, and protein and energy intake.• PEM can be considered as an indication for the initiation of kidney replacement therapy. If PEM develops or persists despite attempts to optimize intake, and there is no apparent cause for malnutrition other than intake or anorexia, initiation of dialysis or kidney transplant is indicated in patients with GFR> 15 mL/min.• Nutritional treatment for patients with CKD should include nutritional assessment and education and nutritional planning and follow-up (AU)

[Advanced chronic kidney disease unit. Concept of a multidisciplinary unit. Objectives of the CKD unit]. / Unidad de enfermedad renal cronica avanzada. Concepto de una unidad multidisciplinaria. Objetivos de la consulta de ERC.

Optimal care of patients with advanced CKD (ACKD) before the initiation of dialysis should include: Early detection of progressive kidney disease Interventions to delay its progression Prevention of uremic complications Reduction of associated comorbid conditions Appropriate preparation and scheduled initiation of KRT. Multidisciplinary teams (MDT) are the future alternative for management of advanced CKD and they should have specific human and material resources.

[Nutrition guidelines for advanced chronic kidney disease (ACKD)]. / Guia de nutricion en enfermedad renal cronica avanzada (ERCA).

Prescription of protein intake in CKD is complicated by potential conflicts between goals to delay progression of CKD and preserve nutritional status. Providing a protein intake of about 0.75 g/kg/day appears reasonable in patients with GRF > 30 mL (CKD stages 1-3). In CKD stage 4 and 5, it is recommended to provide a protein intake of about 0.6 g/kg/day to slow progression and minimize accumulation of uremic toxins. - Maintaining adequate energy intake is essential in all stages of CKD. - Assessment of nutritional status in CKD requires multiple markers to assess protein status, fat stores, body composition, and protein and energy intake. - PEM can be considered as an indication for the initiation of kidney replacement therapy. If PEM develops or persists despite attempts to optimize intake, and there is no apparent cause for malnutrition other than intake or anorexia, initiation of dialysis or kidney transplant is indicated in patients with GFR > 15 mL/min. - Nutritional treatment for patients with CKD should include nutritional assessment and education and nutritional planning and follow-up.

Monitorización de la calidad del agua tratada «on line» y del líquido de diálisis (LD) / No disponible

Introducción: Los tratamientos de agua «on line», están diseñados para obtener agua de gran calidad, condición indispensable, aunque no única, para conseguir LD ultrapuro. Para mantener ésta calidad es precisa la monitorización continua de la calidad del tratamiento del agua, del LD y de los monitores de diálisis. Método: Tras la instalación de un tratamiento de agua con estas características, implementamos un sistema de monitorización que incluía:a) Análisis microbiológicos, endotoxinas y químicos (analíticos y colorimétricos) en el agua en sus diferentes estadios(antes de ser tratada, en diferentes fases del tratamiento y en la red de distribución).b) Control de los parámetros mecánicos de funcionamiento del tratamiento.c) Análisis microbiológico y de endotoxinas del LD.d) Control y mantenimiento de los diferentes monitores de hemodiálisis, según las indicaciones técnicas de los mismos. Resultados: Tras cinco años de funcionamiento se ha evaluado su eficacia y la utilidad de las modificaciones introducidas a lo largo del tiempo. En este periodo no se han registrado contaminación global o parcial del agua después de ser tratada. Los incidentes registrados no han supuesto cortes de suministro o merma de la calidad que haya supuesto la paralización de la unidad de hemodiálisis, pese a los problemas derivados de las malas condiciones en que en ocasiones se encuentra el agua antes de ser tratada. Solo se registró una contaminación persistente en un monitor, que con gran certeza venía originada por el propio puerto para toma de muestras. Conclusiones: Los tratamientos de agua ¿on line¿ para hemodiálisis son los más adecuados para obtener agua de gran calidad. Han de ir acompañados de una monitorización basada en estrictos protocolos de seguimiento creados específicamente para evaluar las características del agua a tratar y tratada (AU)

Introduction: On line-treated water has been designed to obtain ultrapure water. This quality of water is obviously necessary to obtain ultrapure dialysate, although this is not the only condition. To keep the quality of the process, is necessary the continuous monitoring of the water treatment, dialysate and haemodialysis machines. Method: After the installation of a water treatment with these characteristics, we developed a protocol to follow up its quality. The measures included in the protocol were: a. - Microbiologic, endotoxin and chemical controls of the water on different stage: before and at the end of the treatment, pre-treatment and network of distribution. The chemical analysis included analytical and colorimetric measures. b. - Control of specific mechanical functions of the facilities. c. - Microbiologic and endotoxin analysis of the dialysate produced by haemodialysis machines. d. - Control and maintenance of haemodialysis machines, according to the technical indications. Results: We analyse the initial five years of water treatment with the aim to evaluate quality parameters and efficiency. We explain the reasons of the modifications introduced in the system. During this period we have not any episodes of global or partial contamination. We refer here some incidents related with the quality of raw water supply before the treatment, but in any case it was necessary neither to stop the water supply or to reduce the water quality. We observed a persistent contamination of one haemodialysis monitor due to the port used to get the samples. Conclusions: On line-treated water is at present the most appropriate system to obtain high quality water for haemodialysis. The process must be continuously monitored through specific protocols developed to evaluate the raw water's characteristics and the treated water (AU)

[Monitoring on-line treated water and dialysate quality]. / Monitorización de la calidad del agua tratada <> y del líquido de diálisis (LD).

INTRODUCTION: On line-treated water has been designed to obtain ultrapure water. This quality of water is obviously necessary to obtain ultrapure dialysate, although this is not the only condition. To keep the quality of the process, is necessary the continuous monitoring of the water treatment, dialysate and haemodialysis machines. METHOD: After the installation of a water treatment with these characteristics, we developed a protocol to follow up its quality. The measures included in the protocol were: a) Microbiologic, endotoxin and chemical controls of the water on different stage: before and at the end of the treatment, pre-treatment and network of distribution. The chemical analysis included analytical and colorimetric measures. b) Control of specific mechanical functions of the facilities. c) Microbiologic and endotoxin analysis of the dialysate produced by haemodialysis machines. d) Control and maintenance of haemodialysis machines, according to the technical indications. RESULTS: We analyse the initial five years of water treatment with the aim to evaluate quality parameters and efficiency. We explain the reasons of the modifications introduced in the system. During this period we have not any episodes of global or partial contamination. We refer here some incidents related with the quality of raw water supply before the treatment, but in any case it was necessary neither to stop the water supply or to reduce the water quality. We observed a persistent contamination of one haemodialysis monitor due to the port used to get the samples. CONCLUSIONS: On line-treated water is at present the most appropriate system to obtain high quality water for haemodialysis. The process must be continuously monitored through specific protocols developed to evaluate the raw water's characteristics and the treated water.

Community-acquired pneumonia: aetiologic changes in a limited geographic area. An 11-year prospective study.

The aim of this study is to describe the changes in the aetiology of hospitalised patients with community-acquired pneumonia (CAP) during an 11-year observational period in a limited geographic area. Eight hundred and one (801) adult patients with CAP hospitalised were included. The patients were divided into three groups according to the time of presentation. Comprehensive microbiological laboratory tests were performed and differences in aetiology were analysed. In 228 patients (31%), a pathogen was detected, with Coxiella burnetii being the most common (20.1%). Significant variations in the prevalence of Chlamydophila pneumoniae were found between groups but not in other pathogens. In conclusion, long-term epidemiological studies may contribute to the knowledge of actual CAP aetiology.

[Community-acquired pneumonia: influence of the duration of intravenous antibiotic therapy on hospital stay and the cost-benefit ratio]. / Neumonía adquirida en la comunidad: influencia de la duración de la antibioterapia intravenosa en la estancia hospitalaria y relación coste/efectividad.

UNLABELLED: Intravenous antibiotic therapy (IVAT) is usually prescribed for patients hospitalized with community-acquired pneumonia (CAP). Studies have associated prolonged IVAT with longer hospital stays and higher costs. The aim of this study was to determine the factors that influence the expense generated by and mean stay of patients hospitalized for pneumonia, with special attention to the influence of IVAT duration. MATERIAL AND METHODS: One hundred twenty-five CAP patients admitted to the respiratory medicine wards of our hospital were randomly assigned to five different staff physicians. IVAT was prescribed following the norms of the Spanish Society of Respiratory Medicine and Chest Surgery (SEPAR). IVAT was withdrawn when the attending physician considered it appropriate. We collected epidemiological, comorbidity, clinical and analytical data. Complications were recorded and severity of CAP was classified using the model proposed by Fine. Follow-up care was given at an outpatient clinic until symptoms disappeared and chest films resolved. Multivariate analysis determined the factors predicting mean hospital stay and high cost. Costs were calculated based on data issued by the billing department. RESULTS: The mean cost of care was 307,274 pesetas, mean duration of IVAT was 5.8 days and mean hospital stay was 9.4 days. Multivariate analysis showed that cost was related to mean hospital stay and IVAT. Mean hospital stay was associated with IVAT, the presence of respiratory insufficiency and the day of the week when admission took place (with weekend admission leading to longer stays). CONCLUSIONS: The duration of IVAT in CAP influences mean hospital stay and cost, without adding any evident therapeutic benefit (in the group of patients selected). Recommendations for diagnosing and treating CAP may be advisable.

Neumonía adquirida en la comunidad: influencia de la duración de la antibioterapia intravenosa en la estancia hospitalaria y relación coste/efectividad / Community-acquired pneumonia: influence of the duration of intravenous antibiotic therapy on hospital stay and the cost-benefit ratio

Durante el ingreso hospitalario de los pacientes con una neumonía adquirida en la comunidad (NAC) es práctica clínica habitual el empleo de antibioterapia intravenosa (ABIV) durante un período de tiempo no determinado. Diversos estudios han relacionado la prolongación de la ABIV con una mayor estancia media y costes del proceso asistencial. El objetivo de nuestro estudio fue determinar los factores que influyen en el coste económico y en la estancia media de la neumonía que precisa hospitalización, con especial atención a la influencia que la duración de la ABIV tendría en ellos. MATERIAL Y MÉTODOS: Se estudiaron 125 casos de NAC ingresados en la sección de neumología de nuestro hospital, atendidos al azar por cinco médicos distintos de la plantilla. La ABIV se indicó siguiendo la normativa de la SEPAR y se retiró cuando el facultativo responsable lo estimó oportuno. Se recogieron datos epidemiológicos, comorbilidad y datos clínicos y analíticos. Se valoraron complicaciones, y la gravedad de la NAC se clasificó con el modelo propuesto por Fine. Los pacientes fueron seguidos de forma ambulatoria hasta su curación clínica y resolución radiológica. Se realizaron análisis estadísticos multivariados para determinar los factores predictores de estancia media y costes económicos elevados. Los costes se elaboraron a partir de los datos emitidos por el servicio de facturación. RESULTADOS: El coste medio del proceso fue de 307.274 pesetas, la duración media de ABIV, de 5,8 días y la estancia media, de 9,4 días. En el análisis multivariado, el coste económico guardó relación con la estancia media y la duración de ABIV, y por su parte, la estancia media se asoció con la ABIV, la presencia de insuficiencia respiratoria y el día de la semana en que se producía el ingreso (mayor estancia en los ingresos de fin de semana). CONCLUSIONES: La duración de la antibioterapia intravenosa en la NAC influye sobre la estancia media y el coste económico del proceso, sin añadir aparentemente beneficios terapéuticos (en grupos de pacientes seleccionados). Tal vez sería conveniente incluir algunas recomendaciones sobre este punto en futuras normativas sobre diagnóstico y tratamiento de la NAC (AU)

Cytochemical localization of calcium in prefusion myoblasts from the chick embryo myotome.

Myoblast fusion is a Ca2+-dependent process. The aim of this report was to study the localization of Ca2+ in prefusion myoblasts from the brachial somites of chick embryos (51-108 h of incubation), using the potassium pyroantimonate cytochemical method. When observed under a transmission electron microscope, electron-dense precipitates of Ca2+-antimonate were found in the basement membrane of the myotome, which separates the myotome from the adjacent mesenchyma. Within myoblasts, triads and sarcoplasmic reticulum associated with the first newly formed sarcomeres were observed, but a T-tubule network was not found. Moreover, Ca2+-antimonate precipitates were not observed in structures resembling T-tubules or sarcoplasmic reticulum. The results suggest that sarcomerogenesis and sarcoplasmic reticulum development occur simultaneously and that prefusion myoblasts have neither a T-tubule network nor Ca2+ deposits on sarcoplasmic reticulum. Small Ca2+ pools were found in the myoblast nuclei, cytoplasmic vesicles and mitochondrias. Ca2+-antimonate precipitates periodically distributed at the cell periphery, close to the cell membrane, were observed. These precipitates could represent internal Ca2+ stores located in the peripheral couplings and it is proposed that these pools of Ca2+ could be mobilized before fusion, leading to the increase in free intracellular Ca2+ that precedes myoblast fusion.

Intracellular biogenesis of collagen fibrils in 'activated fibroblasts' of tendo Achillis. An ultrastructural study in the New Zealand rabbit.

We have studied the formation of collagen fibrils in 'activated fibroblasts' of tendo Achillis of rabbits. The tendon was in the process of regeneration after experimental partial tenotomy. Samples were taken from the peri-incisional region and analysed by transmission electron microscopy. Ultrastructural examination showed the presence of a 'fine dense granular substance' inside the rough endoplasmic reticulum and procollagen filaments. These come together to form collagen fibrils in the dilated vacuoles of the rough endoplasmic reticulum. The possible intra- and extracellular origin of collagen fibrils is suggested. Within the cell biosynthesis of collagen fibrils take place with the formation of collagen substance which gives rise to procollagen filaments. These make contact in parallel apposition to produce striated 'spindle-shaped bodies' which elongate by the longitudinal attachment of more procollagen filaments and form intracellular nascent collagen fibrils.

The effect of physical conditioning on antipyrine clearance.

The effects of physical conditioning on antipyrine clearance were studied in two groups of subjects. Healthy men not engaged in the systematic practice of any sport were compared with endurance runners (defined as men running > 80 km/week). Studies were carried out at three different periods of the annual plan training at 4-month intervals. Antipyrine was administered orally and pharmacokinetic parameters were obtained from saliva samples by the multiple-sample method. Endurance performance, expressed in terms of the maximal oxygen uptake (VO2max), the ventilatory threshold and the 4-mM x l(-1) lactate threshold (OBLA), was higher in trained than in control subjects at each of the three periods. Antipyrine clearance was also significantly elevated and antipyrine half-life reduced in runners during all periods. No significant difference in VO2max or antipyrine clearance was found between the various periods in either trained or control subjects. Both ventilatory threshold and OBLA increased significantly along the training period in conditioned subjects. Significant correlations were found between antipyrine clearance and VO2max, ventilatory threshold and OBLA. In summary, these results indicate an association between aerobic conditioning and increased hepatic oxidative metabolism of low-clearance drugs.

The use of different fixatives and hydrophilic embedding media (Historesin and Unicryl) for the study of embryonic tissues.

The effects of different fixatives, dehydration procedures, and embedding media on the structural and ultrastructural preservation of young chick embryos (Hamburger and Hamilton stages 18-24) have been studied by means of light and electron microscopy techniques. Under the light microscope, the results obtained with the use of Bouin, glutaraldehyde, or glutaraldehyde-paraformaldehyde mixtures, followed by partial dehydration of the samples and the embedding with two different polar resins (Historesin and Unicryl), were compared with the results obtained using conventional paraffin-embedding methods. Cell and tissue shrinkage was determined by comparing blood cells from those embryos embedded in either of resins with those embedded in paraffin. Samples were also compared with blood smears, either methanol-fixed or unfixed, obtained from embryos at the same Hamburger and Hamilton stages. The results obtained when Unicryl and Araldite were used for electron microscopy have also been compared. When ultrastructural images from glutaraldehyde-tannic acid/osmium tetroxide fixed, Unicryl embedded samples were compared with those from araldite embedded samples, the same good results were observed with either of the resins. Araldite embedding requires a complete dehydration of the samples, while Unicryl allows the embedding of partially dehydrated embryos with optimal ultrastructural results. We suggest that these polar resins can be considered as complementary tools for embedding delicate embryonic tissues, allowing partial dehydration of the specimens with an excellent cell and tissue preservation.

Demonstration of atrial natriuretic peptide immunoreactivity and ultrastructurally related secretory granules in myoblasts of the chick myotome.

In this study, an ultrastructural and immunohistochemical examination was carried out on the presence of an 'atrial-natriuretic-peptide (ANP)-like factor' in the myoblasts of the brachial myotome of chicken embryos at Hamburger and Hamilton stages 17 +/- to 19. The results of the immunohistochemical study indicate that, at these stages of their development, the myoblasts of the brachial myotome show ANP immunoreactivity. The ultrastructural analysis of the myoblasts shows the presence of 'granules' or 'secretory vesicles', similar to the secretory granules which contain natriuretic peptides. The demonstration of immunoreactivity to ANP in the myotome and the specific localization of secretory vesicles in myoblasts, as the first evidence relating ANP with skeletal muscle development, reveal a new site at which an ANP-like factor may be synthesized. The hypothesis of a paracrine and/or autocrine function(s) during myogenesis is suggested.