PubMed Health⌕ Search

Biomedical subjects

C Veiga

Publications and source records attributed to C Veiga.

9 recordsLinked to original sources
PubMed2006

Charon's size and an upper limit on its atmosphere from a stellar occultation.

Pluto and its satellite, Charon (discovered in 1978; ref. 1), appear to form a double planet, rather than a hierarchical planet/satellite couple. Charon is about half Pluto's size and about one-eighth its mass. The precise radii of Pluto and Charon have remained uncertain, leading to large uncertainties on their densities. Although stellar occultations by Charon are in principle a powerful way of measuring its size, they are rare, as the satellite subtends less than 0.3 microradians (0.06 arcsec) on the sky. One occultation (in 1980) yielded a lower limit of 600 km for the satellite's radius, which was later refined to 601.5 km (ref. 4). Here we report observations from a multi-station stellar occultation by Charon, which we use to derive a radius, R(C) = 603.6 +/- 1.4 km (1sigma), and a density of rho = 1.71 +/- 0.08 g cm(-3). This occultation also provides upper limits of 110 and 15 (3sigma) nanobar for an atmosphere around Charon, assuming respectively a pure nitrogen or pure methane atmosphere.

Journal Article↗
PubMed2006

[Myocarditis in the differential diagnosis of acute coronary syndrome].

A 69-year-old man with no remarkable medical history was admitted to the intensive care unit in septic shock due to severe community-acquired pneumonia. Twelve hours later he developed electrocardiographic abnormalities with ST elevation in leads II, III, aVF, V5, and V6 in the absence of chest pain and the presence of dyspnea, agitation, and hypertension. Serial measurements of cardiac enzymes were also elevated. Acute coronary syndrome was suspected. A cardiac ultrasound revealed left ventricular dilation with akinesia and systolic dysfunction (ejection fraction, 40%). Emergency catheterization revealed normal coronary arteries, suggesting a probable diagnosis of acute myocarditis. From the fourth day, the patient was progressing favorably. Findings in a follow-up ultrasound were consistent with the onset of dilated myocardiopathy, and angiotensin converting enzyme inhibitors were prescribed. All serology and microbiological studies were negative. Fifteen days after admission the patient was discharged to home after clinical, radiologic and analytic recovery.

Acute Disease↗
PubMed1998

Synthesis and antiallergic activity of pyridothienopyrimidines.

The synthesis of a series of pyridothienopyrimidines and their evaluation as inhibitors or inducers of the release of histamine from rat mast cells is reported. The activity was measured after immunological stimulation with ovoalbumin and chemical stimulation with polymer 48/80 and the drugs adryamicin and vinorelbine. The experiments were carried out with and without preincubation of the stimulus with the cells before addition of the drug. Several pyridothienopyrimidines show inhibitory IC50 values in the range 2-25 microM, indicating they are up to 100 times more potent than cromoglycate (DSCG) and 10 times greater than Ketotifen. Compound 9l is a potent inhibitor in all the conditions tested and shows IC50 = 9-25 microM. Pyridothienopyrimidines 4l and 9e are very strong inducers of histamine release in the immunological (4l, 170-230%) and chemical (9e, 100-150%) assays, respectively. Compounds 4l and 9i are cytotoxic in vitro (IC50 = 0.1-0.2 microgram/mL) against P-388, A-549, HT-29, and MEL-28 tumor cell lines.

Animals↗
PubMed1997

[Stress tests in old age. The choice of the stress protocol].

OBJECTIVE: To evaluate, in an elderly Portuguese population, the diagnostic capacities of the most popular treadmill stress test protocols. DESIGN: Retrospective study of an elderly Portuguese population submitted to a stress test. PATIENTS AND METHODS: A population of 45 patients (35 male), aged 65 or more years, consecutively submitted to a stress test. The average age of the group was 67.8 +/- 2.9 years. The three protocols (Bruce, Bruce Modified and Naughton) were comparatively studied in terms of the patients capacity to execute the protocol, capacity to obtain a maximum and a diagnostic stress test, and the complications of the stress test protocol. MAIN RESULTS: The Bruce protocol was used in 19 patients, the Bruce Modified in 13 patients and the Naughton protocol in 13 patients. The three protocols did not lead to any complication. The Bruce protocol led to a larger increment in heart rate (p < 0.001) and to larger maximum rate pressure product (p < 0.05) than the Naughton one. The Bruce protocol obtained a larger number of diagnostic tests (p < 0.01) and a significantly lower number of inconclusive stress tests. The Naughton protocol led to a larger duration of the exercise tests and was not suitable for some of the elderly patients owing to the exhaustion of the protocol. The results obtained with the Bruce Modified protocol were among those of other two protocols. CONCLUSIONS: In the elderly, the stress tests are safe and useful in the diagnosis of exercise induced ischemia and in the stratification of cardiovascular risk. From the protocols studied, the Bruce protocol was the most adequate, globally speaking, for this group of patients. The Bruce protocol presented a better diagnostic capacity with no complications related to the protocol.

Aged↗