Biomedical subjects
Publications and source records attributed to A Morales.
Neuropathologic examination of two autopsied patients with Jarcho-Levin syndrome showed no pathologic changes in the brain, spinal cord, or nerve roots of one and diastematomyelia of the thoracolumbar spinal cord in the other. The abnormalities of the spinal cord in one of our patients and in another patient described in the literature establish neural defects as a component of the Jarcho-Levin syndrome.
Epidemiologic studies were conducted during the period 1986-1988 in a small rural community in Colombia (El Callejon) where visceral leishmaniasis is highly endemic. In this community of 185 people, 14 cases of infantile visceral leishmaniasis were diagnosed in the 9 years 1981-1988. Leishmanin skin testing of a sample of the human residents showed that prevalence of Leishmania chagasi infection increased with age; overall, 51.2% of the subjects had a positive reaction. A canine surveillance program was instituted, using introduced sentinel dogs as well as the indigenous dog population. Eleven of 16 sentinel dogs were infected within 8 months of exposure; mean seroconversion time was 4.4 months. Eleven of 25 seronegative local dogs were also infected during the 26 month period; mean seroconversion time was 8 months. Parasites identified by isozyme electrophoresis as L. chagasi were recovered from 18 of 22 seropositive dogs. Collections of wild animals using baited live traps yielded mainly the neotropical opossum, Didelphis marsupialis. Leishmania chagasi was recovered from 12 of 37 (32.4%) opossums. Six of 681 female Lutzomyia longipalpis collected in the community had flagellates in their guts; cultures from 4 were identified as L. chagasi. These data confirmed that active parasite transmission occurred. The relatively high prevalence of L. chagasi infection found among D. marsupialis captured near human dwellings suggests that these animals may be an important peridomestic reservoir.
Rats with mammillary electrolytic lesions show a strong polydipsia and polyuria. This over-consumption may be primary or secondary to the polyuric effect. In this regard, mammillary lesioned rats excrete a greater amount of urine compared with control animals when matched in daily water consumption (partial water deprivation). Moreover, this abnormal water intake is significantly reversed by treatment with Pitressin, a vasopressin analogue. These results suggest that the polydipsia may be determined by the urinary water loss. However, when subjected to the bilateral ureter ligation, the experimental animals still outdrink the control ones, thus also suggesting a primary component of the polydipsia under study. The possible explanation of these components in relation to the mammillary polydipsia is discussed.
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Most studies of gastric transmucosal potential difference concern acute damage. We studied this phenomenon in 168 patients with different pathologic processes: erosive gastritis, duodenal and prepyloric ulcer, atrophic gastritis, gastric ulcer and normal controls. Ag-AgCl electrodes and Agar-KCl bridges were used to record potential differences. Biopsies were taken from gastric antrum and body and potential differences were related to endoscopic and histologic findings. Maximal values of -29.2 + 2 and -22.2 + 1.6 for body and antrum, respectively, were found in normals. Lowest values (-19.4 + 1.4 and -14.3 + 1.5, respectively) were found in gastric ulcer, with intermediate values for the other conditions. Normal histologic findings were associated to potentials of -31 + 2 and -20 + 3.1 whereas lower values were recorded in patients with moderate or severe atrophic changes. Our findings suggest a relation between mucosal atrophy and lower transmucosal potential differences.
A potential difference is generated by the active transport of electrolytes through low permeability epithelium such as the gastric and esophageal mucosa. A decrease in this potential has been proposed as an indicator of mucosal damage. We measured potential difference in 151 patients undergoing endoscopy for duodenal ulcer, gastritis or as a control group. Mean for the whole group was -18 + 0.5 mV, range -4 to -37. No differences were found among groups. Due to the ample variation in potential difference both at the gastric and esophageal levels, its determination was of no use in localizing the boundary between gastric and esophageal mucosa.
Five new phlebotomus fever virus serotypes (Bunyaviridae: Phlebovirus) are described. These viruses, designated Ambe, Ixcanal, Mariquita, Armero, and Durania, were isolated from sand flies (Diptera: Psychodidae) collected in Brazil, Colombia, and Guatemala. Two of the agents were recovered from pools of male sand flies. The new viruses are antigenically related to other members of the phlebotomus fever serogroup by immunofluorescence, but are distinct from the other 39 members of this serogroup by plaque reduction neutralization test.
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Several brain areas have been implicated in the regulation of water intake and body fluid homeostasis. Electrolytic lesions located in the mammillary area have proved to induce a strong polydipsia. The cause of this overconsumption is not understood, although other studies have indicated a possible relationship with the mechanisms involved in sodium control. In this paper, we consider whether mammillary polydipsia is related to diabetes insipidus. In this regard, animals with mammillary lesions were submitted to several dipsogenic treatments, both osmotic and volemic. These subjects showed a differential response to hypertonic NaCl compared with controls. No effect could be seen in relation to the other treatments employed, that is, sucrose and polyethylene glycol. On the other hand, this differential response to NaCl was not observed in those animals with diabetes insipidus centrally induced by means of lesions in the median eminence. Thus, mammillary polydipsia and diabetes insipidus-related water intake seem to be different phenomena. The possible relationship between mammillary polydipsia and sodium control is discussed.
We describe 2 children with bladder hemangiomas. The diagnosis, pathology and treatment of these lesions in children are reviewed.
In an effort to obtain a more precise definition of erectile sufficiency for vaginal penetration 19 normal men were exposed to an erotic videotape and recordings of penile tumescence were obtained. The subjects were instructed to signal with a push button switch when they had attained an erection they judged sufficient for penetration. They were asked to signal a second time when a full erection had been reached. The results showed that in all but 1 case maximal tumescence was recorded polygraphically before the subjects signaled sufficiency. In addition, there was a considerable interval between the perception of sufficiency and the perception of a full erection during which, nevertheless, no further changes could be detected by strain gauge measurement. These data suggest that standard assessment techniques are not sensitive to penile changes in the upper ranges of tumescence. Of interest to the developing area of diurnal penile tumescence for the etiological diagnosis of impotence was the observation that a significant percentage (37 per cent) of normal subjects were unable to achieve a full erection during visual sexual stimulation under laboratory conditions.
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1. The properties of sensory neurones in the petrosal ganglion of the cat were examined in vitro with intracellular electrodes 2-30 days after cutting the carotid or the glossopharyngeal nerve or 30-120 days after crushing the nerves and allowing time for peripheral reinnervation. Both glossopharyngeal and carotid neurones with conduction velocities faster than 2 m/s and humps on the falling phase of their action potentials were studied. 2. Two days after axotomy, the action potential of glossopharyngeal cells showed increased maximum rate of depolarization and decreased after-hyperpolarization (AHP) amplitude. These cells also showed a decrease in time-dependent inward rectification and conduction velocity. No significant changes were observed in carotid neurones at this stage. 3. Four days after axotomy, these changes were still present in glossopharyngeal cells and the duration of the AHP had also decreased. Among carotid neurones there was an increase in spike duration and a decrease in time-dependent rectification and in the amplitude and duration of the AHP. 4. Eight days after axotomy glossopharyngeal cells additionally showed an increased spike duration and decreased rheobase, while carotid neurones had also decreased in conduction velocity. 5. All the changes described were still present 16 days after cutting the nerves. In addition, the input resistance increased in both types of cells. 6. The effects of axotomy persisted 30 days after cutting the nerve, except for the AHP amplitude in both types of cells and the spike duration in glossopharyngeal neurones which had recovered to near control values. 7. Thirty days after crushing the carotid nerve, some carotid neurones showed chemosensory activity, indicating that reinnervation of the carotid body had taken place. In these cells, the properties altered by axotomy had recovered except for the conduction velocity. 8. Four months after crushing the glossopharyngeal nerve, activity evoked by mechanical and chemical stimulation of the tongue could be recorded from the nerve, indicating that sensory reinnervation had taken place. The electrical properties of the glossopharyngeal cells were normal except for conduction velocity which was still slower than the control value. 9. It is concluded that the electrical membrane properties altered by axotomy revert to normal after peripheral sensory regeneration.