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Biomedical subjects

J Trujillo

Publications and source records attributed to J Trujillo.

84 records · Page 5Linked to original sources
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Granuloma formation and parasite disintegration in porcine cysticercosis: comparison with human neurocysticercosis.

Taenia solium cysticerci infect human beings and pigs, causing cysticercosis. In this study the pig was used as a model to characterize the immune response against cysticerci, given the difficulties in analysing the developing immune response in infected human brains. Metacestodes in different stages of viability or degeneration were isolated from the brain, heart and skeletal muscle of naturally infected swine, and the adjacent tissue was examined histologically. The immune response elicited by the cysticerci was classified into four separate stages. In stage I the parasites were surrounded by a thin layer of collagen type I, and by stage II there was a sparse inflammatory infiltrate. In stage III, granuloma formation was evident, and by stage IV the parasite was surrounded by an eosinophil-rich infiltrate and its vesicular membrane had begun to degenerate. The final stage, IV, was detected mainly in the heart but not in the brain. The granulomatous reaction in swine resembled that described previously in human patients, but differed in the abundance of eosinophils, the relative paucity of plasma cells, and the discrete deposition of collagen. These differences were probably due to the fact that in pigs the immune response can be examined earlier than in human patients, in whom sampling is inevitably made at a more chronic stage.

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Fibrotic sequelae in pulmonary paracoccidioidomycosis: histopathological aspects in BALB/c mice infected with viable and non-viable paracoccidioides brasiliensis propagules.

Patients with paracoccidioidomycosis often present pulmonary fibrosis and exhibit important respiratory limitations. Based on an already established animal model, the contribution of viable and non-viable P. brasiliensis propagules to the development of fibrosis was investigated. BALB/c male mice, 4-6 weeks old were inoculated intranasally either with 4x10(6) viable conidia (Group I), or 6. 5x10(6) fragmented yeast cells (Group II). Control animals received PBS. Six mice per period were sacrificed at 24, 48, 72h (initial) and 1, 2, 4, 8, 12 and 16 weeks post-challenge (late). Paraffin embedded lungs were sectioned and stained with H&E, trichromic (Masson), reticulin and Grocot&tacute;s. During the initial period PMNs influx was important in both groups and acute inflammation involving 34% to 45% of the lungs was noticed. Later on, mononuclear cells predominated. In group I, the inflammation progressed and granulomas were formed and by the 12th week they fussed and became loose. Thick collagen I fibers were observed in 66.6% and 83.3% of the animals at 8 and 12 weeks, respectively. Collagen III, thick fibers became apparent in some animals at 4 weeks and by 12 weeks, 83% of them exhibited alterations in the organization and thickness of these elements. In group II mice, this pattern was different with stepwise decrease in the number of inflammatory foci and lack of granulomas. Although initially most animals in this group had minor alterations in thin collagen I fibers, they disappeared by the 4th week. Results indicate that tissue response to fragmented yeast cells was transitory while viable conidia evoked a progressive inflammatory reaction leading to granuloma formation and to excess production and/or disarrangement of collagens I and III; the latter led to fibrosis.

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[Changes in the vasoconstrictor action of noradrenaline and in its receptor-binding kinetics induced by sex hormones].

The role of testosterone/17 B estradiol ratios (T/E), on the vasoconstrictor effect of norepinephrine (NE), were studied in strips of carotid arteries from dogs. T/E of 0.1 (T = 1 nM/E = 10 nM) shifted the concentration/effect (C-E) curve of NE to the right. T/E of 10 (T = 10 nM/E = 1 nM) deviated it to the left. T (1 nM and 10 nM) shifted the C-E curve of NE to the right; E = 1 nM did not modify it; E = 10 nM, shifted it to the left. In microsomal fraction of carotid arteries, adrenergic receptors were characterized with 3H-NE binding, and the role of T/E ratios also studied. Under the influence of T/E ratio of 10, the agonist affinity (Ka), was increased from 100 nM-1 to 128 nM-1, the receptors density (Bmax), increased from 78.3 nM to 148 nM. E (1 nM) reduced Ka to 88 nM-1, T did not change any of these parameters. In conclusion, T/E ratios of 10, as in male, may enhance the vasoconstrictor activity of NE, increasing Ka and Bmax of adrenergic receptors.

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PubMedDate not supplied

[Effects of the polyamines putrescine, spermidine and spermine on the hypertensive action of norepinephrine in anesthetized dogs].

In anesthetized and vagotomized dogs, we investigate the associative effects on blood pressure of norepinephrine (NE) with the three polyamines putrescine (Pt), spermidine (Sd) and spermine (Se). Experimental series were performed under beta adrenergic blockade (propranolol 0.5 mg/Kg, iv.), alpha adrenergic blockade (phenoxybenzamine 15 mg/Kg, iv.), and under calcium antagonistic action (verapamil 0.3 mg/Kg, iv.). The three polyamines induced a potentiation on the hypertensive effect of NE, they change the dose/response curve to the left side in a potency rank of Se greater than Sd greater than Pt. Such potentiation was not different when a beta adrenergic blockade or calcium antagonism was present; however phenoxybenzamine neutralized it. On the other side, polyamines had a hypotensive effect when were administered alone to the animals. Such effect is related to a histamine releasing properties of the polyamines, and was abolished by previous administration of anihistaminic agents chlorpheniramine (5 mg/kg, iv.) and cimetidine (20 mg/Kg, iv.). In conclusion our results indicate that the potentiation of the hypertensive effect of NE by polyamines, could be attained through a mechanism which involves the alpha adrenergic receptors of the vascular smooth muscle but is not related to the calcium channels that show voltage dependence.

Anesthesia↗
PubMedDate not supplied

Antiulcerogenicity of the flavonoid fraction from Erica andevalensis Cabezudo-Rivera.

Investigations were carried out to determine the antiulcerogenicity of the flavonoid fraction (ethyl acetate extract) of Erica andevalensis Cabezudo-Rivera on gastric ulceration induced by different experimental models. Oral treatment with the ethyl acetate extract and the major flavonoid (myricetin 3-O-D-galactoside) were found to be effective to prevent gastric ulceration induced by cold-restraint stress in rats. Statistically significant ulcer index values with respect to the control group were observed. Mucus content was not increased although it was accompanied by an increase in proteins and hexosamines. In pyloric-ligated animals flavonoids showed a significant reduction in the number and severity of the ulcers. Under the same conditions acidity did not decrease with the flavonoid extract and myricetin 3-O-D-galactoside significantly as compared to control. Gastric ulcers induced by oral administration of absolute ethanol were reduced by pretreatment with the flavonoid extract of doses from 125 to 250 mg/kg and the isolated flavonoid of 25 mg/kg p.o. However neither the flavonic extract nor the isolated flavonoid induced changes in the amount and glycoprotein content of gastric mucus.

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