Fine structure and cytochemical analysis of the intestinal wall along the body of adult female of Litomosoides chagasfilhoi (Nematoda: Filarioidea).

Litomosoides chagasfilhoi is a filariid nematode parasite of the abdominal cavity of the wild rodent Akodon cursor (Winge, 1887), that has been described and used in Brazil as a new model for human filariasis. The fine structure of the intestine of this nematode was analyzed based on observations made by light and transmission electron microscopies of serial sections along the body. Cytochemical analysis was carried out to investigate the composition of the intestinal wall. This structure consisted of a basal lamina and an epithelium of variable thickness, composed of cells that have an irregular shape. The cytoplasm of intestinal cells contains few organelles: vacuoles, lysosomal bodies, spheroid bodies, endoplasmic reticulum, and many large lipid droplets. In the anterior portion of the intestine, the lysosomal bodies, spheroid bodies, and vacuoles presented positive reaction for acid phosphatase, and carbohydrates were detected in lysosomal bodies. The midbody and posterior regions presented less organelles and lipid droplets, and nuclei were more abundant. Residues of L-fucose were detected by Ulex europaeus lectin binding in the midbody sections. Basic proteins were associated to lipid droplets, in the posterior region. In the whole extension of the intestine, carbohydrates were detected on tight junctions. These results indicate that the metabolized material in the epithelium can contribute to the microfilariae development and also probably can be involved with the excretory/secretory mechanism of these nematodes.

Absence of vacuolar membrane involving Toxoplasma gondii during its intranuclear localization.

Tachyzoites of Toxoplasma gondii were located inside the nucleus of both skeletal muscle cells infected in vitro and peritoneal exudate cells collected from infected mouse in vivo. Ultrastructural analysis demonstrated that T. gondii invades the nucleus of host cells by the parasite apical region and with constriction of its body. We noted that the rhoptry, a secretory organelle of the parasite that is involved in the host cell invasion mechanism, was empty in the intranuclear T. gondii. The parasites were found in the nuclear matrix without evidence of the vacuolar membrane. Frequently, new parasites invaded host cell nucleus, which was already infected. The significance of this nuclear invasion could reflect an alternative route of T. gondii for its transitory survival or an escape mechanism from the host immune response during the in vivo infection (or both).

Dietary fiber intake, stool frequency and colonic transit time in chronic functional constipation in children

The objective of the present study was to evaluate associations between fiber intake, colonic transit time and stool frequency. Thirty-eight patients aged 4 to 14 years were submitted to alimentary evaluation and to measurement of colonic transit time. The median fiber intake of the total sample was age + 10.3 g/day. Only 18.4 percent of the subjects presented a daily dietary fiber intake below the levels recommended by the American Health Foundation. In this group, the median left colonic transit time was shorter than in the group with higher dietary fiber intake (11 vs 17 h, P = 0.067). The correlation between stool frequency and colonic transit time was negative and weak for left colon (r = -0.3, P = 0.04), and negative and moderate for rectosigmoid and total colon (r = -0.5, P<0.001 and r = -0.5, P<0.001, respectively). The stool frequency was lower in the group with slow transit time (0.8 vs 2.3 per week, P = 0.014). In conclusion, most patients with chronic functional constipation had adequate dietary fiber intake. The negative correlation between stool frequency and colonic transit time increased progressively from proximal segments to distal segments of the colon. Patients with normal and prolonged colonic transit time differ in terms of stool frequency

Dietary fiber intake, stool frequency and colonic transit time in chronic functional constipation in children.

The objective of the present study was to evaluate associations between fiber intake, colonic transit time and stool frequency. Thirty-eight patients aged 4 to 14 years were submitted to alimentary evaluation and to measurement of colonic transit time. The median fiber intake of the total sample was age + 10.3 g/day. Only 18.4% of the subjects presented a daily dietary fiber intake below the levels recommended by the American Health Foundation. In this group, the median left colonic transit time was shorter than in the group with higher dietary fiber intake (11 vs 17 h, P = 0.067). The correlation between stool frequency and colonic transit time was negative and weak for left colon (r = -0.3, P = 0.04), and negative and moderate for rectosigmoid and total colon (r = -0.5, P<0.001 and r = -0.5, P<0.001, respectively). The stool frequency was lower in the group with slow transit time (0.8 vs 2.3 per week, P = 0.014). In conclusion, most patients with chronic functional constipation had adequate dietary fiber intake. The negative correlation between stool frequency and colonic transit time increased progressively from proximal segments to distal segments of the colon. Patients with normal and prolonged colonic transit time differ in terms of stool frequency.