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Biomedical subjects

S Hernandez

Publications and source records attributed to S Hernandez.

44 records · Page 3Linked to original sources
PubMedDate not supplied

Pathological and immunohistochemical study of the abomasum and abomasal lymph nodes in goats experimentally infected with Haemonchus contortus.

Histopathological changes and the distributions of T and B lymphocytes and IgG producing plasma cells were recorded in the abomasum and abomasal lymph nodes of goats 3, 7 and 21 weeks post-infection (wpi) after an experimental infection with H. contortus. The low rate of worm recovery by 3 wpi (5.6%) might have been due to larvae death as suggested by the presence of granulomas in the abomasal mucosa at 3 and 7 wpi, or simply due to a poor larval establishment. Marked increase in the secretion of mucus by mucous cells together with an abundant infiltration of eosinophils, mast cells, CD3+ T lymphocytes, CD79a+ B cells, IgG+ plasma cells and globule leukocytes were recorded in the abomasal mucosa, especially at 7 wpi. Except for the globule leukocytes, this reaction decreased substantially by week 21, suggesting this cell type may have been involved in rejection of adult nematodes. The abomasal lymph nodes showed marked hyperplasia, particularly of CD79a+ B cells and IgG+ plasma cells in all infected goats. These reactions may have been responsible for the reduction in the number of worms found in the abomasum between 3 and 7 wpi.

Abomasum↗
PubMedDate not supplied

Chromosome abnormalities and sister chromatid exchanges in children with acute intoxication due to inhalation of volatile substances.

Deliberate inhalation of volatile substances is a common and harmful practice among young persons worldwide. Recently, we described chromosome damage in children who chronically inhale volatile agents. Clinical and cytogenetic studies were performed for 15 "sniffing" children (13 boys and 2 girls), the purpose of which was to define the chromosomal effect of the acute intoxication. A significant increase in the rate of chromosome abnormalities and in the frequency of sister chromatid exchanges (SCEs) was found in sniffers vs. controls. The values were also higher in children who were acutely intoxicated than in those who chronically inhaled volatile agents. Clinical, socioeconomic, and cytogenetic findings are also discussed.

Adolescent↗
PubMedDate not supplied

Kainic acid-induced limbic seizures in cats: some reflections on sleep-epilepsy interactions.

Sleep-epilepsy interactions were investigated in a model of temporal lobe seizures induced in cats by intra-amygdaloid kainic acid (KA) microinjections. We found that limbic status epilepticus disrupted sleep for 2 or 3 days after injection. Sleep, in turn, modulated the frequency of interictal discharges. However, such modulation was variable depending on the time elapsed since KA injection. For this and other reasons (such as the occurrence of subclinical seizures during paradoxical sleep), we postulate a dual effect--facilitatory or inhibitory--of paradoxical sleep on limbic epilepsy. A role in seizure induction for bulbopontine structures is proposed on the basis of seizure precipitation during phasic paradoxical sleep. Propagated limbic seizures and paradoxical sleep without atonia displayed similar behavioral patterns. This fact and the possibility that a seizure may substitute for paradoxical sleep, lead us to think that limbic seizures and paradoxical sleep subserve similar functions. One of them might be the elimination of a potentially neurotoxic endogenous product.

Animals↗
PubMedDate not supplied

Antibodies to Helicobacter pylori and pepsinogen levels in children from Costa Rica: comparison of two areas with different risks for stomach cancer.

In children and adolescents from two areas of Costa Rica with contrasting gastric cancer risks, two factors suspected to be linked to the natural history of the disease were tested: serum antibodies to Helicobacter pylori and serum pepsinogen levels. One hundred fifty-five subjects from the high-risk area of Turrubares were compared to 127 from the low-risk area of Hojancha. No significant differences were found in the prevalence of IgG or IgA antibodies to Helicobacter pylori between the two regions. The prevalence of IgG was 65.8% in the high-risk area and 72.4 in the low-risk area, and that of IgA was 43% in both areas. The levels of pepsinogen, especially pepsinogen C, were significantly elevated in subjects with H. pylori antibodies in their serum. The mean levels of pepsinogen C in those negative, positive, and strong positive for H. pylori antibodies were 8.7, 14.3, and 21.1 ng/ml. These findings suggest that H. pylori-associated gastritis, predominantly of antral localization, is very prevalent in Costa Rican children and adolescents. Such gastritis might be associated with a high prevalence of intestinal metaplasia and a high gastric cancer risk in the inland, but not the coastal rural populations. H. pylori may therefore be an insufficient cause whose role in gastric carcinogenesis is contingent upon the presence of other factors.

Adolescent↗