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Biomedical subjects

G Mendoza

Publications and source records attributed to G Mendoza.

48 records · Page 3Linked to original sources
PubMed1975

Ionophore A-23187 induced histamine release from rat mast cells and rat basophil leukemia (RBL-1) cells.

Ionophore A-23187 releases histamine from normal mast cells apparently by promoting Ca++ influx (Foreman et al, Nature 245: 249, 1973). In our hands at concentrations of greater than 0.2 mug/ml release occurs in 1 to 2 min, is blocked by metabolic inhibitors, and is unaccompanied by cytotoxicity (trypan-blue uptake, lactic dehydrogenase (LDH) release). At higher doses (0.5 mug/ml) histamine release is followed by significant cytotoxicity, but again Ca++ is required. In parallel studies, we examined cultured rat basophilic leukemia (RBL-1) cells. These cells, which apparently have normal surface receptors for IgE, contained approximately 700 ng histamine/10(6) cells but did not release histamine when IgE-mediated release was looked for. They do not respond to doses of ionophore which would be expected to give non-cytotoxic histamine release. At higher doses histamine release is preceded by progressive LDH release: LDH release is 75% complete at 5 min whereas 10 min are required for 75% maximal histamine release. This reaction requires Ca++ and is temperature dependent but is not inhibited by metabolic poisons (2-deoxyglucose, dinitrophenol, CN-). These studies suggest that either Ca++ does not enter into these cells normally or that one or more mechanisms which are ordinarily triggered by the changes in Ca++ flow are unresponsive in the RBL-1 cells. These studies also underline the importance of ruling out cytotoxicity in ionophore-induced phenomena.

Animals↗
PubMed1973

Human echinococcosis (hydatidosis) in Uruguay: a comparison of indices of morbidity and mortality, 1962-71.

The number of hospital cases of hydatid disease diagnosed in Uruguay during the 10 years 1962-1971 was determined by retrospective survey of all medical and surgical centres on three occasions. The annual index of hospital cases was compared with the estimated real prevalence of infection in man determined by extrapolation from the rates of intrathoracic hydatid cysts detected by mass miniature radiography. The highest rates of infection, as determined by these methods, were observed in the interior departments, particularly among rural populations, although some infections were apparently acquired in the capital department of Montevideo. The national index of hospital cases was the highest yet reported for any country but comparison with indices of estimated prevalence indicated that diagnosed cases were only a small proportion of existing infections. The different indices of human prevalence, particularly in the younger age groups, are expected to serve as baseline data to measure future changes in infection pressure achieved as a result of the control measures recently initiated.

Adolescent↗
PubMedDate not supplied

Alien hand sign after a right parietal infarction.

Involuntary movements are unusual during or after acute stroke, and alien hand sign has not been reported after single parietal infarction. We report on a woman who presented with involuntary movements and a sense of alienness of her left upper limb following a right parietal infarction. This combination, that can meet the criteria for the 'alien hand syndrome', is rarely seen after acute lesions sparing the corpus callosum and the mesial frontal areas.

Aged↗
PubMedDate not supplied

Ontogeny of clenched-hand development in trisomy 18 fetuses: A serial transabdominal fetoscopic observation.

Malpositioning of the fingers is a characteristic anomaly in fetuses with trisomy 18. The defect results in part from muscle variations along the radial margin of forearm and hand, absence of the thenar muscles, anomalous tendons and attachments among the forearm groups, and fusions among the arm flexor group. These variations result in radial or ulnar displacement of the tendons of extensor digitorum and digiti minimi, with overlapping of the fourth and fifth fingers radially and second finger in an ulnar direction. The ontogeny of these changes is unknown. We performed serial transabdominal thin-gauge fetoscopy in a patient with increased nuchal thickening at 12 weeks of pregnancy at the time of genetic testing and again at 14 weeks at the time of termination of pregnancy. Changes in the positioning of the fingers were not apparent at 12 weeks, but were evident at 14 weeks. The findings were beyond the resolution of ultrasound. We conclude that malpositioning of the fingers in trisomy 18 occurs some time between 12 and 14 weeks of gestation. Noninvasive confirmation of these findings may be possible with new and improved ultrasound imaging capabilities or perhaps with three-dimensional ultrasound.

Adult↗
PubMedDate not supplied

[Renal trauma].

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Accidents, Traffic↗