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Biomedical subjects

M E Castillo

Publications and source records attributed to M E Castillo.

10 recordsLinked to original sources
PubMed1996

Lysophospholipase L2 of Vibrio cholerae O1 affects cholera toxin production.

The implication in cholera toxin (CT) production of the newly identified gene, lypA, that encodes the lysophospholipase L2 of Vibrio cholerae, was investigated. Introduction of lypA into the V. cholerae O1 mutant (NF404), which has a Tn5-insertion in lypA and has lost CT as well as haemolysin production, restored the lysophospholipase activity and CT production but not the haemolytic activity. Inactivation of the lypA gene of the wild-type strain by chromosomal integration of a plasmid containing a portion of the lypA gene decreased the lysophospholipase L2 activity and the production of CT but not the haemolytic activity. Furthermore, constructed mutants of E1 Tor-biotype and Classical-biotype strains which have a defective lypA failed to produce CT and exhibited decreased enterotoxicity in the ligated rabbit ileal loop test. These results suggest that lypA is possibly required for the expression of CT and may play a role in pathogenicity of V. cholerae.

Animals↗
PubMed1989

Peripheral pathways mediating salivary secretion after nucleus parvocellularis activation in the rat.

The present study demonstrates that activation of the nucleus parvocellularis in the pontine reticular formation of the rat evokes salivary hypersecretion. The secretory effect observed was found to be mediated by parasympathetic mechanisms, as transection of the preganglionic parasympathetic salivatory fibers at the level of the middle ear blocked the flow of saliva evoked by activation of the nucleus parvocellularis (Experiment 1). Furthermore, transection of these salivatory fibers was followed several days later by the development of a prandial model of drinking. These behavioral data suggest that the transection procedure employed in the present study indeed affected those parasympathetic fibers which control the secretory activity of all three pairs of major salivary glands (Experiment 2).

Animals↗
PubMed1989

Effects of atropine injection on food-associated drinking in rats with superior salivatory nucleus lesions.

The neuropharmacological mechanisms involved in the prandial drinking pattern seen in rats with superior salivatory nucleus lesions + parotidectomy were investigated with behavioral methods. Results showed that the administration of low doses (0.1 mg/kg body wt) of atropine in lesioned rats potentiated previously established prandial drinking. Higher doses of atropine (1.0 mg/kg), however, were required to induce a similar degree of prandiality in control rats (parotidectomy alone). These findings suggest that the salivatory nucleus lesions affected a cholinergic brainstem-salivary gland system involved in the neural control of food-associated drinking.

Animals↗
PubMed1988

Submandibular and parotid salivary secretion after electrolytic lesioning of the brainstem nucleus parvocellularis in the rat.

The present study, in consonance with recent anatomical investigations, demonstrates that activation of the nucleus parvocellularis in the rat evokes a potent hypersecretory effect in the submandibular and sublingual (S-S) salivary glands. Furthermore, electrolytic lesioning of this region in conjunction with peripheral removal of the parotid glands is followed by an increase in the number of drinking responses in the presence of dry food. Such prandial drinking behavior is only observed after total impairment of salivation (i.e., removal of the S-S + parotid glands), thus suggesting that the parvocellularis lesion led to a marked deficit in S-S salivary secretion. On the other hand, the activation of the nucleus parvocellularis was seen to have only a slight effect on parotid salivary secretion. Electrolytic lesions to this zone, when associated with peripheral removal of the S-S glands, failed to induce prandiality, suggesting that the parvocellularis nucleus exerted a low level of control over parotid salivary secretion. These results are interpreted as functional proof of the relationship between the parvocellularis reticular formation and the superior salivatory nucleus in the secretion of S-S saliva.

Animals↗
PubMed1988

Salivatory neurons in the brainstem nucleus parvocellularis of the rat: effects of electrolytic lesions.

This study was based on several recent anatomical studies suggesting that the superior salivatory nucleus is located within the area parvocellularis of the brainstem reticular formation. The aforementioned zone was lesioned in order to observe the alterations produced in salivary secretion. Electrolytic lesion of the area parvocellularis was followed by salivary hypersecretion as an immediate and transitory effect of the stimulatory capacity of the electrolytic lesioning method. Some days later the animals presented a markedly impaired salivary secretion as shown by the appearance of inefficient feeding behavior and the development of a prandial drinking pattern. The prandial behavior, which was characterized by numerous drinking episodes during dry food intake, was reversed when wet food was offered, suggesting a true deficit in salivary secretion caused by the parvocellularis lesion. Following the administration of pilocarpine, the submandibular and sublingual salivary glands of experimental animals showed an increased capacity for response (postsynaptic supersensitivity) in comparison to the control group.

Animals↗
PubMed1981

[Panniculitis in pancreatic diseases].

A case of panniculitis in a patient with a pancreatic pseudocyst is described. Etiologic possibilities of the dermic lesions are analized, pointing out the role of the antiproteolytic enzymes and immunologic factors. In our patient neither immunologic or alpha-1-antitrypsin anomalies were detected. The skin lesions are probably related to the release of the pancreatic enzymes into the blood.

Adult↗
PubMed1978

[Epidermolysis bullosa letalis].

A case of epidermolysis bullosa letalis in a newborn is described by the authors. The girl had numerous lesions for all the tegument except on the face, palms and soles. Something of them were bullous. The histopathological examination revealed a bulla with detachement dermoepidermic. Without infiltrate in dermis. The roof of the bullae is conservate. In the PAS stain we show the detachement over of the basal membrane.

Epidermolysis Bullosa↗