Insights on the epigenetic mechanisms underlying pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH), characterized by localized increased arterial blood pressure in the lungs, is a slow developing long-term disease that can be fatal. PAH is characterized by inflammation, vascular tone imbalance, pathological pulmonary vascular remodeling, and right-sided heart failure. Current treatments for PAH are palliative and development of new therapies is necessary. Recent and relevant studies have demonstrated that epigenetic processes may exert key influences on the pathogenesis of PAH and may be promising therapeutic targets in the prevention and/or cure of this condition. The aim of the present mini-review is to summarize the occurrence of epigenetic-based mechanisms in the context of PAH physiopathology, focusing on the roles of DNA methylation, histone post-translational modifications and non-coding RNAs. We also discuss the potential of epigenetic-based therapies for PAH.

Insights on the epigenetic mechanisms underlying pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH), characterized by localized increased arterial blood pressure in the lungs, is a slow developing long-term disease that can be fatal. PAH is characterized by inflammation, vascular tone imbalance, pathological pulmonary vascular remodeling, and right-sided heart failure. Current treatments for PAH are palliative and development of new therapies is necessary. Recent and relevant studies have demonstrated that epigenetic processes may exert key influences on the pathogenesis of PAH and may be promising therapeutic targets in the prevention and/or cure of this condition. The aim of the present mini-review is to summarize the occurrence of epigenetic-based mechanisms in the context of PAH physiopathology, focusing on the roles of DNA methylation, histone post-translational modifications and non-coding RNAs. We also discuss the potential of epigenetic-based therapies for PAH.

The effect of both protein and vitamin b complex deficiency on the morphoquantitative features of the myenteric plexus of the ascending colon of adult rats / Efeito da carência de proteínas e vitaminas do complexo b sobre aspectos morfoquantitativos do plexo mioentérico do colo ascendente de ratos adultos / Efecto de la carencia de proteínas y vitaminas del complejo b sobre aspectos morfo-cuantitativos del plexo mioentérico del regazo ascendiente en ratones adultos

O objetivo deste estudo foi estudar os efeitos da desnutrição protéica e da carência de vitaminas do complexo B sobre o plexo mioentérico do colo ascendente de Rattus norvegicus. Vinte ratos foram divididos em dois grupos, sendo que, para um dos grupos foi oferecida ração com teor protéico de 22% (controle) e, para outro, ração com teor protéico de 8% com menor teor de vitaminas do complexo B, durante 120 dias. Coramos os preparados de membrana do colo ascendente pelo método de Giemsa e pela técnica da NADH-diaforase. Os ratos desnutridos apresentaram peso corporal 14,8% menor que o grupo controle, média da área do colo 54,2% menor, e a média da densidade neuronal foi 26,7% maior com a técnica de Giemsa e 27% com a técnica da NADH-diaforase. Como a redução da área não foi acompanhada por um aumento inversamente proporcional na densidade de neurônios, sugere-se que a condição imposta causou perda de neurônios mioentéricos.

This study was performed in order to study the effects of protein desnutrition and vitamin B complex deficiency on the myenteric plexus of the ascending colon of Rattus norvegicus. Twenty rats were divided into two groups; one had been fed with a 22%-protein-level ration, and the other with a 8%-protein-level without vitamin-B-complex supplementation, for 120 days. The whole-amounts of the ascending colon were stained with either Giemsa or NADH-diaphorase technique. The disnurtured rats showed a 14.8% smaller body weight than the control group, and the area of colon of the sample group was 54.2% smaller. The average neuronal density was 26.7% greater with the Giemsa technique and 27% greater with the NADH-diaphorase technique. As the decrease in area was not accompanied by an inversely proportional increase in neuronal density, it is suggested that the experimental condition led to a myenteric neuron loss.

El objetivo de este estudio fue analisar los efectos de la desnutrición proteica y de la carencia de vitaminas del complejo B sobre el plexo mioentérico del regazo ascendiente de Rattus norvegicus. Veinte ratones fueron divididos en dos grupos, siendo que, para uno de los grupos se ofreció ración con contenido proteico de 22% (control) y, para el otro, ración con contenido proteico de 8% con menor contenido de vitaminas del complejo B, durante 120 días. Coloreamos los preparados de membrana del regazo ascendiente por el método de Giemsa y por la técnica de la NADH-diaforasis. Los ratones desnutridos presentaron peso corporal 14,8% menor que el grupo control, promedio del área del regazo de 54,2% menor, y el promedio de la densidad neuronal fue 26,7% mayor con la técnica de Giemsa y 27% con la técnica de la NADH-diaforasis. Como la reducción del área no fue acompañada por un aumento inversamente proporcional en la densidad de neuronas, se cree que la condición impuesta causó pérdida de neuronas mioentéricos.

Morphoquantitative aspects of NADH-diaphorase myenteric neurons in the ileum of diabetic rats treated with acetyl-L-carnitine.

In this work, we investigated the effect of the acetyl-L-carnitine (ALC) supplementation (200 mg/kg/day) on the myenteric neurons of the ileum of rats made diabetic by streptozotocin (35 mg/kg, i.v.). Four groups were used: diabetic (D), diabetic supplemented with ALC (DC), control (C) and control supplemented with ALC (CC). After 15 weeks of diabetes induction the animals were killed and the ileum was collected and subjected to whole-mount preparation to evidence the myenteric neurons through the histochemical technique of the NADH-diaphorase. The density of neurons seen in 12.72 mm2 of ileum showed no difference among the groups, although in group D it was 22% smaller than in group C, while group DC was 9% smaller to group CC. The profiles of the cell bodies (PC) of 1000 neurons per group were analysed. The neurons PC in group D decreased (P < 0.0001) when compared with other groups and increased (P < 0.0001) when compared with group DC. The incidence of neurons with a PC inferior to 200 microm2 was larger in group D. The frequency of neurons with a PC higher than 200 microm2 in group DC was close to those seen in groups C and CC. We concluded that ALC eases the loss of neurons and makes the incidence of myenteric neurons with a PC higher than 200 microm2 similar to the control rats.

Biometric and food consumption parameters of rats subjected to hypoproteic and hipercaloric diet / Parâmetros biométricos e de consumo alimentar de ratos submetidos à dieta hipoprotéica e hipercalórica / Parámetros biométricos y de consumo alimentar de ratones sometidos a la dieta hipoprotéica e hipercalórica

A carência de proteínas, causando Kwashiorkor, é o tipo de má-nutrição mais prevalente, pois fontes de alimentos protéicos, geralmente, são mais onerosas. Para estudos experimentais, o rato tem sido o principal modelo para avaliar as conseqüências de ingestão de dietas com diferentes teores protéicos, contudo ainda não estão claros os níveis de severidade dessas dietas para essa espécie. Nesse sentido, propõe-se avaliar a severidade de uma dieta hipoprotéica a 4% para ratos jovens. Para tanto, utilizaram-se 30 ratos Wistar (90 dias de idade), os quais foram divididos em dois grupos: controle (GC) e experimental (GC). O GC recebeu dieta normoprotéica, enquanto o GE recebeu dieta com 4% de teor de proteínas, ambos, durante 12 semanas. No final do experimento, avaliaram-se o peso, o crescimento, a massa gorda e massa magra dos animais. Os animais do GE não ganharam peso, tiveram retardo no crescimento, formaram menos massa gorda e menos massa muscular.

ABSTRACT: The protein lack causing Kwashiorkor is the most prevalent kind of malnutrition, because the food sources of proteins are usually more expensive. For experimental investigations, the rat has provided the primary model to evaluate the consequences of the ingestion of diets with different protein levels; however, the degrees of severity of these diets for thesespecies are still not clear. In this sense, we aimed at evaluating the severity of a 4%-hypoproteic diet on young rats. We used30 Wistar rats (90 days old), which were divided in two groups: control (CG) and experimental (EG). CG rats were fed with normoprotein chow, while EG rats were fed with a chow having 4% protein, for 12 weeks. At the end of the experiment, we evaluated the weight, growth, and fat and lean masses of the animals. The rats from EG did not gain weight, they had growth retardation, and built less fat and muscle masses.

RESUMO: A carência de proteínas, causando Kwashiorkor, é o tipo de má-nutrição mais prevalente, pois fontes de alimentos protéicos, geralmente, são mais onerosas. Para estudos experimentais, o rato tem sido o principal modelo para avaliar as conseqüências de ingestão de dietas com diferentes teores protéicos, contudo ainda não estão claros os níveis de severidade dessas dietas para essa espécie. Nesse sentido, propõe-se avaliar a severidade de uma dieta hipoprotéica a 4% para ratos jovens. Para tanto, utilizaram-se 30 ratos Wistar (90 dias de idade), os quais foram divididos em dois grupos: controle (GC) e experimental (GC). O GC recebeu dieta normoprotéica, enquanto o GE recebeu dieta com 4% de teor de proteínas, ambos, durante 12 semanas. No fi nal do experimento, avaliaram-se o peso, o crescimento, a massa gorda e massa magra dos animais. Os animais do GE não ganharam peso, tiveram retardo no crescimento, formaram menos massa gorda e menos massa muscular.

Hematologic and biochemical parameters of rats subjected to hypoproteic and hipercaloric diet / Parâmetros hematológicos e bioquímicos de ratos submetidos à dieta hipoprotéica e hipercalórica / Parámetros hematológicos y bioquímicos de ratones sometidos a la dieta hipoprotéica e hipercalórica

A má-nutrição é um problema de saúde pública que ainda assola crianças e adultos no mundo inteiro, principalmente em países em desenvolvimento. A carência de proteínas, causando Kwashiorkor, é o tipo de má-nutrição mais prevalente, pois fontes de alimentos protéicos, geralmente, são mais onerosas. Uma dieta hipoprotéica causa alterações metabólicas num animal em intensidades diretamente proporcionais ao nível de depleção de proteínas, bem como o tempo em que o indivíduo permanece sob o estado de subnutrição. Nesse sentido, propõe-se avaliar a severidade de uma dieta hipoprotéica a 4% para ratos jovens. Utilizam-se 30 ratos Wistar (90 dias de idade), divididos em grupo controle (15) e experimental (15). O GC recebeu dieta normoprotéica, enquanto o GE recebeu dieta com 4% de teor de proteínas, ambos durante 12 semanas. No final do experimento, sangue foi coletado para realização de hemograma e dosagem de atividade de fosfatase alcalina, alanina aminotrasferase, além da concentração de proteínas totais e frações, colesterol total, triglicerídeos, uréia, ácido úrico, T3, T4 e aminoácidos plasmáticos. Os animais do GE demonstraram menor atividade defosfatase alcalina no sangue, anemia microcítica normocrômica, hipoproteinemia, hipoglobulinemia, reduação na concentração plasmática de triglicerídeos, aumento da concentração plasmática de T3 e T4 e diminuição da concentração plasmática dos seguintes aminoácidos: metionina, fenilalanina, valina, leucina e isoleucina.

ABSTRACT: Malnutrition is a public health issue which still affects children and adults all over the world, especially in developing countries. Protein defi ciency causing Kwashiorkor is the most prevalent type of malnutrition, because protein-rich foods are generally expensive. A hypoproteic diet causes metabolic alterations in an animal which are directly proportional to the degree of protein depletion, as well as to the duration of the malnutrition. In this sense, we proposed to evaluate the severity of a 4%-hypoproteic diet in young rats. We used 30 Wistar rats (90 days of age), divided in control (CG, n=15) and experimental (EG, n=15) groups. CG was fed with a normoprotein chow, while EG was fed with a diet having 4% protein, for 12 weeks. At the end of the experiment, blood was collected for determination of the hemogram, activities of alkaline phosphatase and alanine aminotransferase, and concentration of total and fractional proteins, total cholesterol, triglycerides,urea, uric acid, T3, T4 and plasma aminoacids. The animals from EG had lower activity of the alkaline phosphatase enzyme in blood, normochromic microcytic anemia, hypoproteinemia, hypoglobulinemia, decreased plasma triglyceride concentration, increased plasma concentrations of T3 and T4, and decreased plasma concentrations of the following aminoacids: methionine, phenylalanine, valine, leucine and isoleucine

RESUMEN: La mala nutrición es un problema de salud pública que todavía aniquila niños y adultos en el mundo entero, principalmente en países en desarrollo. La falta de proteínas, causando Kwashiorkor, es el tipo de mala nutrición más común, pues fuentes de alimentos proteicos, generalmente, son más caras. Una dieta poco proteica causa alteraciones metabólicas en un animal en intensidades directamente proporcionales al nivel de depleción de proteínas, así como el tiempo en que el individuo queda bajo el estado de baja nutrición. En ese sentido, proponemos evaluar la severidad de una dieta de bajo contenido proteico al 4% para ratones jóvenes. Utilizamos 30 ratones Wistar (90 días de edad), divididos en grupo control (15) y experimental (15). El GC recibió dieta normoproteica, mientras el GE recibió dieta con el 4% de cantidad de proteínas, ambos durante 12 semanas. Al fi nal del experimento, sangre fue recolectado para realización del examen de la sangre y cantidad de actividad de fosfatase alcalina, alanina aminotrasferase, además de la concentración de proteínas totales y fracciones, colesterol total, triglicerídeos, urea, ácido úrico, T3, T4 y aminoácidos plasmáticos. Los animales del GE demostraron menor actividad de fosfatase alcalina en la sangre, anemia microcítica normocrómica, hipoproteinemía, hipoglobulinemia, reducción en la concentración plasmática de triglicerídeos, aumento de la plasmática de T3 y T4 y disminución de la concentración plasmática de los siguientes aminoácidos: metionina, fenilalanina, valina, leucina y isoleucina

Three-dimensional distribution of the collagen fibers in the submucosa of the swine terminal ileum.

Collagen has an important role in controlling mechanical function and physiopathology of intestinal wall. Swine small intestine may be used as biomaterial source for tissue repairing. Changes of collagen arrangement and three-dimensional (3D) distribution may be related to the dissimilar biomechanical proprieties showed by different intestine tracts. 3D spatial distribution of collagen bundles of swine submucosal terminal ileum (SSTI) was studied by a correlated analysis of light (LM) and scanning electron microscopy (SEM) of NaOH macerated samples. Bundles of collagen fibers were greatly represented in the submucosa at the mesenteric border and also extended along the longitudinal folds beneath mucosa layer. Polarized LM of picrosirius stained samples evidenced yellow and red fibers (type I collagen), and green fibers (type III collagen). Silver-impregnated sections showed predominant brown-stained fibers and, in a smaller amount, black-stained ones. By SEM submucosal collagen, isolated by NaOH maceration, appeared arranged in wide bundles forming a complicated 3-D network. The bundles presented a sinuous course, opened and closed repeatedly forming meshes fashioned in a regular net. These observations originally demonstrated that 3-D distribution of SSTI collagen is different from that observed in other gut segments and species. The arrangement of SSTI collagen fibers that we observed seems to be morphofunctionally adjusted to provide appropriate resistance to mechanical forces and to assure compliance to deformations induced by intestinal wall motion. The studies for selection of optimal intestinal patches for surgical replacement should take into consideration the basic morphological evaluation of parietal collagen 3D distribution.

Effects of supplementation with ascorbic acid for a period of 120 days on the myosin-V and NADPHd positive myenteric neurons of the ileum of rats.

We investigated the effect of ascorbic acid (AA) supplementation on the NADPH-diaphorase (NADPHd) and myosin-V myenteric neurons in the ileum of rats, after 4 months of treatment. Two groups were compared, i.e. controls rats (C) and AA-treated rats (CA). Myosin-V immunohistochemistry and NADPHd histochemistry were employed. We investigated the areas of 500 cell bodies of myosin-V neurons and of 500 NADPHd stained neurons from all groups. The quantitative analysis was performed using an area of 8.96 mm2 from each ileum. There was an increase of 21.9% in the myosin-V immunoreactive myenteric neurons (P > 0.05) and of 22.5% in the NADPHd in group CA when compared with C (P < 0.05). There were no significant differences when we compared the area of myosin-V stained neurons between groups C and CA. However, we verified an area reduction of 7.5% in NADPHd neurons when comparing group C to group CA (P < 0.05).

Morphometric and quantitative evaluation of the NADH-diaphorase positive myenteric neurons of the jejunum of streptozotocin-diabetic rats supplemented with acetyl-L-carnitine.

Summary In this study we investigated the effect of the acetyl-L-carnitine (ALC) supplementation on the myenteric neurons of the jejunum of rats made diabetic at the age of 105 days by streptozotocin (35 mg/kg body weight). Four groups were used: non-diabetic (C), non-diabetic supplemented with ALC (CC), diabetic (D), diabetic supplemented with ALC (DC). After 15 weeks of diabetes induction the blood was collected by cardiac puncture to evaluate glycaemia and glycated haemoglobin. Next the animals were killed and the jejunum was collected and subjected to whole-mount preparation to evidence the myenteric neurons through the histochemical technique of the NADH-diaphorase. The neuronal counts were made in 80 microscopic fields, in tissue samples of five animals of each group. The profiles of the cell bodies of 1000 neurons per group were analysed. Diabetes induced a significant increase in the area of the cell body and decrease in the number of NADH-diaphorase positive myoenteric neurons. ALC suplementation to the diabetic group promoted smaller hypertrophic effects and less neuronal loss than in the myoenteric neurons of the diabetic rats, and in addition diminished the body weight decrease and reduced the fasting glycaemia.

Morphoquantitative aspects of nitrergic myoenteric neurons from the stomach of diabetic rats supplemented with acetyl-L-carnitine.

The NADPH-diaphorase (NADPH-d) positive myoenteric neurons from the body of the stomach of rats with streptozotocin-induced diabetes with or without supplementation with acetyl-L-carnitine (ALC) were evaluated. At the age of 105 days the animals were divided into four groups: normoglycaemic (C), normoglycaemic supplemented with ALC (CC), diabetic (D) and diabetic supplemented with ALC (DC). The supplementation with ALC (200 mg/kg body weight/day) to groups CC and DC was made during 105 days. After this period the animals were killed and the stomach removed and subjected to the histochemical technique of NADPH-d for the staining of the neurons of the myoenteric plexus. The area of 500 neurons of each group was investigated, as well as the neuronal density in an area of 23.84 mm(2) in each stomach. ALC promoted reduction (P < 0.05) of fasting glycaemia, water ingestion and areas of the profiles of the cell bodies of the NADPH-d neurons in the diabetic animals. The density of these neurons was not statistically different in the groups studied. It is suggested, therefore, a moderate neuroprotective effect of ALC, because the diminishment of the areas of the neuronal profiles in the supplemented diabetic animals, although being statistically significant relative to the non-supplemented diabetics, was not sufficient to equal the values from the non-diabetic controls.

Evaluation of the population of NADPH-diaphorase-stained and myosin-V myenteric neurons in the ileum of chronically streptozotocin-diabetic rats treated with ascorbic acid.

We investigated the effect of the ascorbic acid on the nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d)-stained and myosin-V myenteric neurons in the ileum of chronically diabetic rats. The study was performed 4 months after inducing experimental diabetes with streptozotocin. Diabetic rats showed increased (p<0.05) glycaemia and glycated haemoglobin. Three groups were compared, i.e., nondiabetic rats, diabetic rats and diabetic rats treated with ascorbic acid. Myosin-V immunohistochemistry and NADPH-d histochemistry were employed. We investigated the areas of 500 cell bodies of myosin-V neurons and of 500 NADPH-d-stained neurons from all groups. The quantitative analysis was performed by using an area of 8.96 mm(2) from each ileum. The two groups of diabetic rats and diabetic rats treated with ascorbic acid showed reduction in the number and an increased area of the myosin-V-immunostained myenteric neurons. In addition, we observed increased relative proportion of NADPH-d-stained neurons in diabetic rats and diabetic rats treated with ascorbic acid. However, the area of these neurons in the diabetic rats group was larger than those evidenced in the nondiabetic rats and diabetic rats treated with ascorbic acid.

Effects of protein and vitamin B deficiency on blood parameters and myenteric neurons of the colon of rats.

The aims of this work were to evaluate the effects of the deficient ingestion of protein and vitamin B on the biochemical and hematologic parameters and on the NADH- and NADPH-diaphorase positive myenteric neurons. The control animals (n=10) received commercial chow and the experimental rats (n=10) received chow with protein level reduced to 8% during 120 days. At the time of killing blood was collected for assessment of the blood and hematologic parameters and the ascending colon for quantitative analysis of the neurons of the myenteric plexus. It was observed that the reduction of the protein level to 8% coupled to the reduction of the levels of vitamin B in adult rats neither led to qualitative or quantitative changes on red or white blood cells, nor decreased globulin levels, induced the formation of edema or gave rise to clinical signs typical of protein or vitamin B deficiency. On the other hand, the experimental protocol led to less weight gain, change on the body composition with fat deposition; decrease of the values of serum total protein and albumin; reduction of the area of colon and density of nitrergic and NADH-diaphorase myenteric neurons inferior to the expected.

Quantitative study of the myenteric plexus of the stomach of rats with streptozotocin-induced diabetes.

The purpose of the present study was to investigate the morphological and quantitative alterations of the myenteric plexus neurons of the stomach of rats with streptozotocin-induced chronic diabetes and compare them to those of non-diabetic animals. Samples from the body of the stomach were used for whole-mount preparations stained with NADH-diaphorase and for histological sections stained with hematoxylin-eosin. It was observed that diabetes cause a significant decrease on the number of neurons.

Regional differences in the number and type of myenteric neurons of the ileum of rats: a comparison of techniques of the neuronal evidentiation.

We carried out this study with the purpose of analyzing the density of neurons of the myenteric plexus in the mesenteric, intermediate and antimesenteric regions of the ileum of rats. Whole-mounts stained with four different techniques were employed. Through countings under optic microscope in an area of 8.96 mm2 we found the following neuronal means with the techniques of Giemsa, NADH-diaphorase histochemistry, NADPH-diaphorase and acetylcholinesterase, respectively: mesenteric region 2144.40+/-161.05, 1657.80+/-88.23, 473.80+/-19.62, 905.25+/-22.40; intermediate region 1790.60+/-128.24, 1265.20+/-141.17, 371.30+/-27.84, 770.25+/-33.12; antimesenteric region 1647.0+/-76.67, 981.80+/-68.04, 298.50+/-22.75, 704.50+/-69.38. We conclude that there is a variation of neuronal density around the intestinal circumference and this fact independs on the technique used to stain the neurons, and that in a single region the neuronal density varies with the technique employed. We also call attention for the identification of the site were countings were carried out, so that the results of research in this area are not compromised.

Streptozotocin-induced diabetes duration is important to determine changes in the number and basophily of myenteric neurons.

The aim of present study was to evaluate the number and basophily of cell bodies of myenteric neurons in the ileum of rats with diabetes mellitus induced by streptozotocin. Four groups of rats were used: diabetes was induced in two (D) whereas the other two worked as controls (N). Animals were sacrificed six (6N, 6D) or nineteen (19N, 19D) weeks after diabetes induction. A segment of the terminal portion of the ileum of each rat was obtained and stained with Giemsa's solution, for whole-mount preparation studies. Forty fields were analyzed in each animal, and the number and basophily intensity of cell bodies were recorded. After counting, the following mean numbers of neurons/mm2 were obtained: 6N=593.1 +/- 95.75, 6D=639.1 +/- 130.8, 19N=580.1 +/- 175.6 and 19D=402.0 +/- 144.8. The analysis of basophily shown that highest frequency of neurons with weak/intermediary basophily was verified in 6D group (55.3%), whereas the groups 6N, 19N e 19D presented 38%, 36% e 40% respectively. The statistical analysis showed that a long period is necessary to decrease the number of neurons/mm2 in the rat ileum after diabetes induction, and that there was a reduction in basophily intensity in diabetic rats after 6 weeks of treatment, and such cells do not recover after a longer period (19 weeks).

Arrangement of the tunica muscularis of the ileum, cecum and colon at the transition between the small and the large intestines of swine.

The arrangement of the bundles of muscular fibers in the transition between the small and the large intestines was studied in 12 male adult crossbred swine by dissection, after immersion in 50% nitric acid solution. The connection between the small and the large intestines was formed by the association of the muscular tissue, the connective tissue and the fat tissue. The tunica muscularis of these organs was organized in thin thread-like bundles and wide ribbon-like bundles of variable width and thickness. The superficial bundles of the longitudinal stratum of the tunica muscularis of the ileum established the continuity with the large intestine; the deep bundles penetrated into the ileal papilla. The limit between the cecum and the ascending colon was externally marked by the sulcus cecocolicus dorsalis and ventralis. The connection between the cecum and the ascending colon was formed by bundles of muscular fibers coming from the ileum, and the taeniae ventralis, lateralis and medialis of the cecum. Some bundles of muscular fibers from the ascending colon and the cecum headed toward the sulcus cecocolicus. The median bundles of muscular fibers of the taenia ventralis of the cecum, near the termination of the ileum, were arranged to form a loop around the termination of the ileum, mixing with the musculature of the ascending colon at the level of this junction.

Evaluation of the areas of neuronal cell bodies and nuclei in the myenteric plexus of the duodenum of adult rats.

This study compared the areas of cell body and nucleus profiles of the myenteric neurons in the antimesenteric and intermediate regions of the duodenum of adult rats. Five male rats were used. The duodenum was removed and dissected to whole-mount preparations, which were stained by the Giemsa technique. The areas of cell body and nucleus profiles of 100 neurons, 50 from each region, of each animal, were assessed with image analyser. Based on the global mean+/-SD of the areas of cell body profiles, neurons were labelled as small, medium or large. It was observed that the neurons did not differ significantly in size or incidence between the antimesenteric and intermediate regions. However, the nuclei of the small and medium neurons were significantly smaller in the latter region. It is discussed that the smaller nuclear size could be related to the cell bodies being slightly smaller on this region and to a possible smaller biosynthetic activity which would influence nuclear size.

Ultrastructural features of myenteric ganglia of adult Wistar rats (Rattus norvegicus).

The ultrastructural features of the ganglia of the myenteric plexus exhibit changes according to the animal species. These myenteric ganglia in the duodenum of adult rats of the Wistar strain were characterized ultrastructurally in this work. Those ganglia were depicted as compact structures, composed of neurones and glial cells, forming a dense neuropil surrounded by a continuous basal lamina and collagen fibrils. Glial cell bodies were smaller and apparently more frequent than neuronal cell bodies, being morphologically distinguished by nuclear features. In the neuronal extensions granular and agranular synaptic vesicles of different sizes predominate, in addition to mitochondria and myelinized profiles. Gliofilaments were not observed on the glial extensions of the rats.

Paracoccidioides brasilienses isolates obtained from patients with acute and chronic disease exhibit morphological differences after animal passage.

The basis for virulence in Paracoccidioides brasiliensis is not completely understood. There is a consensus that the sequential in vitro subcultivation of P. brasiliensis leads to loss of its pathogenicity, which can be reverted by reisolation from animal passage. Attention to morphological and biochemical properties that are regained or demonstrated after animal passage may provide new insights into factors related to the pathogenicity and virulence of P. brasiliensis. We evaluated morphological characters: the percentage of budding cells, number of buds by cell and the diameter of 100 mother cells of yeast-like cells of 30 P. brasiliensis isolates, before and after animal passage. The isolates were obtained from patients with different clinical forms of paracoccidioidomycosis (PCM): acute form (group A, n=15) and chronic form (group C, n=15). The measurement of the yeast cell sizes was carried out with the aid of an Olympus CBB microscope coupled with a micrometer disc. We measured the major transverse and longitudinal axes of 100 viable cells of each preparation. The percentage of budding cells as also the number of buds by cell was not influenced by animal passage, regardless of the source of the strain (acute or chronic groups). The size values of P. brasiliensis isolates from groups A and C, measured before the animal passage exhibited the same behavior. After animal passage, there was a statistically significant difference between the cell sizes of P. brasiliensis isolates recovered from testicles inoculated with strains from groups A and C. The maximum diameter of mother cells from group A isolates exhibited a size of 42.1 microm in contrast with 32.9 microm exhibited by mother cells from group C (p<0.05). The diameter of 1500 mother cells from group A isolates exhibited a medium size of 16.0 microm (SD +/- 4.0), a value significantly higher than the 14.1 microm (SD = +/- 3.3) exhibited by 1500 mother cells from group C isolates (p<0.05). Our results reinforce the polymorphism exhibited by P. brasiliensis in biological material and the need for further investigations to elucidate the role of morphological parameters of the fungus in the natural history of the disease.

Morphologic and quantitative study of the myenteric neurons of the jejunum of malnourished rats (Rattus norvegicus).

We studied the effects of maternal proteic desnutrition on the neurons of the myenteric plexus of the jejunum of rats from Rattus norvegicus species. It was used litters of female rats which received diet with normal proteic level during gestation and lactation (group NN), normal diet during gestation and hypoproteic diet during lactation (group ND); hypoproteic diet during gestation and normal diet during lactation (group DN); hypoproteic diet during both gestation and lactation (group DD). After weaning all the animals received diet of normal proteic level until the 60th day of age, when they were killed. The jejunum of the animals was subjected to whole-mount preparations stained by the method of Giemsa and used for the morphologic and quantitative analyses of the neurons of the myenteric plexus. We verified that maternal proteic malnutrition does not cause decrease on the number of myenteric neurons per unit area of jejunum in rats, but elicits mechanisms which assure that, when the animal again receives normal proteic level diet (22%) there occurs storage of proteic material on the cytoplasm of the neurons, thus rendering them larger and strongly basophylic.