Biomedical subjects

Carlos Gonzalez

Publications and source records attributed to Carlos Gonzalez.

21 records · Page 2Linked to original sources

PubMedDate not supplied

Age at menopause in Latin America.

OBJECTIVE: To assess the age at menopause (AM) in Latin America urban areas. DESIGN: A total of 17,150 healthy women, aged 40 to 59 years, accompanying patients to healthcare centers in 47 cities of 15 Latin American countries, were surveyed regarding their age, educational level, healthcare coverage, history of gynecological surgery, smoking habit, presence of menses, and the use of contraception or hormone therapy at menopause. The AM was calculated using logit analysis. RESULTS: The mean age of the entire sample was 49.4 +/- 5.5 years. Mean educational level was 9.9 +/- 4.5 years, and the use of hormone therapy and oral contraception was 22.1% and 7.9%, respectively. The median AM of women in all centers was 48.6 years, ranging from 43.8 years in Asuncion (Paraguay) to 53 years in Cartagena de Indias (Colombia). Logistic regression analysis determined that women aged 49 living in cities at 2,000 meters or more above sea level (OR = 2.0, 95% CI: 1.4-2.9, P < 0.001) and those with lower educational level (OR = 1.9, 95% CI: 1.3-2.8, P < 0.001) or living in countries with low gross national product (OR = 2.1, 95% CI: 1.5-2.9, P < 0.001) were more prone to an earlier onset of menopause. CONCLUSIONS: The AM varies widely in Latin America. Lower income and related poverty conditions influence the onset of menopause.

Adult↗

PubMedDate not supplied

Temperature effects, arrhenius activation parameters and rate constants for the photochemical reactivity of cyano, boronato, trifluoromethyl and methoxy substituted toluenes in the excited singlet state.

Total rate constants of decay (k(t)) as a function of temperature from -45 to +65 degrees C for the compounds 1 and 2 in AN and TFE and 3 and 4 in AN have been determined by fluorescence lifetime measurements. The data have been fit to an equation that assumes that the rate constants of fluorescence (k(f)) and intersystem crossing (k(isc)) are temperature independent, that k(ic) = 0 and that the rate constant of reaction (k(r)) is activated according to the Arrhenius expression. For compounds 1-3, values of k(f) and k(isc) were found to be independent of solvent for any given compound, but k(r) was consistently greater in TFE than AN. For the anisoles 4, the temperature effect was very small, indicating that k(r) did not compete with k(f) + k(isc) and suggesting that an activated intersystem crossing was the dominant temperature-dependent process. The k(r), A and E(a) values obtained for compounds 1-3 were rationalized in terms of their known photochemistry, phototransposition reactions in AN and photoadditions in TFE. The critical reactive intermediate in all cases is a bicycle[3.1.0]hexenyl biradical/zwitterion that is formed in an activated process from S1. This reactive intermediate returns to starting material faster than it rearranges, and therefore an activated internal conversion is a major pathway for deactivation of S1.

Journal Article↗

PubMedDate not supplied

Is this a case of simple soft tissue mass?

A 15-year-old girl reports a 1-year history of a mass on the lower portion of her left leg associated with occasional pain. Antero-posterior and lateral radiography, T1 and T2 magnetic resonance imaging (MRI), and bone/joint whole body scan were performed.

Adolescent↗