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Biomedical subjects

Manuel Herrera

Publications and source records attributed to Manuel Herrera.

4 recordsLinked to original sources

Differences in ocular dimensions between normal and dry eyes.

Assessment of ocular dimensions is essential for ophthalmic surgeons because these values must be determined before scheduling excimer laser refractive and cataract surgeries. Dry eye seems to affect central corneal thickness (CCT) values, but it is not clear if it affects anterior chamber depth (ACD), lens thickness (LT), vitreous chamber depth (VCD) and axial length values. Following on from this, we measured the CCT, ACD, LT, VCD and axial length of 64 healthy eyes (51.20%) and 61 dry eyes (48.80%). CCT was measured with scanning-slit corneal topography (Orbscan Topography System II, Orbscan, Inc., Salt Lake City, UT, USA) and ACD, LT, VCD and axial length with a 10-MHz A-mode ultrasound device (Compuscan; Storz, St. Louis, MO, USA). There were no significant differences in ACD (P=0.588), LT (P=0.739), VCD (P=0.568) and axial length (P=0.199) between normal and dry eyes. Nevertheless, the differences in CCT between normal (549+/-34 microm) and dry eyes (527+/-30 microm) were significant (P<0.001). In sum, it seems that only the CCT values are significantly lower in subjects with dry eye.

Adult↗

Quantitative anatomical differences in central corneal thickness values determined with scanning-slit corneal topography and noncontact specular microscopy.

PURPOSE: This study was designed to analyze the differences in central corneal thickness values determined with noncontact specular microscopy and scanning-slit corneal topography. The measurements were performed on the same eye. METHODS: We analyzed the central corneal thickness values of 93 patients (n = 93) by means of noncontact specular microscopy (Topcon SP-2000P noncontact specular microscope, Topcon Corp., Tokyo, Japan) and scanning-slit corneal topography (Orbscan Topography System II, Orbscan Inc., Salt Lake City, UT). One experienced physician performed 3 consecutive central corneal thickness measurements with both devices. RESULTS: The central corneal thickness values obtained by means of Orbscan pachymetry were 17 +/- 2.7 (range, 12-24) microm greater. A significant correlation was observed between scanning-slit corneal topography and noncontact specular microscopy (Pearson correlation coefficient, r = 0.976; P < 0.001). CONCLUSIONS: Researchers should know of the existence of this difference between noncontact specular microscopy and Orbscan pachymetry when interpreting central corneal thickness values.

Adult↗

Splenic haemorrhage in a newborn as the first manifestation of wandering spleen syndrome.

Wandering spleen is an unusual condition in children and is even more rarely diagnosed in the neonatal period. A case of splenic haemorrhage after dystocic birth in a newborn is reported. Before surgery, results of imaging studies were suggestive of a ruptured spleen. On laparotomy, a big haematoma surrounding a wandering spleen was found. Haemorrhage aroused from short splenic arteria. Haemostasia and splenopexy were performed. The spleen proved later to be viable. The authors speculate that the haemorrhage was the first manifestation of the wandering spleen.

Adult↗

The PACARDO research project: youthful drug involvement in Central America and the Dominican Republic.

OBJECTIVE: To estimate the occurrence and school-level clustering of drug involvement among school-attending adolescent youths in each of seven countries in Latin America, drawing upon evidence from the PACARDO research project, a multinational collaborative epidemiological research study. METHODS: During 1999-2000, anonymous self-administered questionnaires on drug involvement and related behaviors were administered to a cross-sectional, nationally representative sample that included a total of 12,797 students in the following seven countries: Costa Rica (n = 1,702), the Dominican Republic (n = 2,023), El Salvador (n = 1,628), Guatemala (n = 2,530), Honduras (n = 1,752), Nicaragua (n = , 419), and Panama (n = 1,743). (The PACARDO name concatenates PA for Panamá, CA for Centroamérica, and RDO for República Dominicana). Estimates for exposure opportunity and actual use of alcohol, tobacco, inhalants, marijuana, cocaine (crack/coca paste), amphetamines and methamphetamines, tranquilizers, ecstasy, and heroin were assessed via responses about questions on age of first chance to try each drug, and first use. Logistic regression models accounting for the complex survey design were used to estimate the associations of interest. RESULTS: Cumulative occurrence estimates for alcohol, tobacco, inhalants, marijuana, and illegal drug use for the overall sample were, respectively: 52%, 29%, 5%, 4%, and 5%. In comparison to females, males were more likely to use alcohol, tobacco, inhalants, marijuana, and illegal drugs; the odds ratio estimates were 1.3, 2.1, 1.6, 4.1, and 3.2, respectively. School-level clustering was noted in all countries for alcohol and tobacco use; it was also noted in Costa Rica, El Salvador, Guatemala, and Panama for illegal drug use. CONCLUSIONS: This report sheds new light on adolescent drug experiences in Panama, the five Spanish-heritage countries of Central America, and the Dominican Republic, and presents the first estimates of school-level clustering of youthful drug involvement in these seven countries. Placed in relation to school survey findings from North America and Europe, these estimates indicate lower levels of drug involvement in these seven countries of the Americas. For example, in the United States of America 70% of surveyed youths had tried alcohol and 59% had smoked tobacco. By comparison, in these seven countries, only 51% have tried alcohol and only 29% have smoked tobacco. Future research will help to clarify explanations for the observed variations across different countries of the world. In the meantime, strengthening of school-based and other prevention efforts in the seven-country PACARDO area may help these countries slow the spread of youthful drug involvement, reduce school-level clustering, and avoid the periodic epidemics of illegal drug use that have been experienced in North America.

Adolescent↗