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Biomedical subjects

L Rivera

Publications and source records attributed to L Rivera.

At least 73 records · Page 4Linked to original sources
PubMed1985

Low endemicity and low pathogenicity of rotaviruses among rural children in Costa Rica.

Rotaviruses were prospectively studied in 51 rural Costa Rican children from birth to two years. Samples of feces were collected weekly over a 33-month period. Rotavirus was detected in 45 (1.04%) of 4,317 fecal specimens; 39 infections were documented (an incidence of 0.5 infection per child-year), only five of which were associated with diarrhea (a pathogenicity of 12.8%). Secretory antibody in fecal extracts, detected in six of 39 infections, was short lived and did not protect against reinfection. Serum antibody was present in 69.6% of two-year-old children, but was not detected in 18.8% with documented infections. On the other hand, serum antibody was present in six of 14 children in whom rotavirus was not detected, thus increasing the overall incidence to 0.6 infection per child-year. The combination of prolonged breast-feeding, exposure to a lower infecting dose (compared with urban children), and a higher standard of hygiene than expected may explain the low incidence and low pathogenicity of rotavirus among these rural children.

Age Factors↗
PubMed1980

Safety effectiveness of closed-transfer, mixing-loading, and application equipment in preventing exposure to pesticides.

Blood cholinesterase (CHE) activities and urinary dialkyl phosphate levels of five mixer-loaders and four mixer-loader applicators, using a closed-transfer system in conjunction with mixing-loading and application equipment, were monitored over a period of 18 weeks. Airborne pesticide residues in the breathing zone during mixing-loading and the transfer of concentrated liquid pesticide from their original container to mix and spray tanks were determined along with airborne residues during ground application. Blood ChE activities of the majority of the workers increased slightly during the study with increased use of toxic organophosphates and carbamates. Urinary dialkyl phosphate levels varied between 0.02 and 2.4 ppm. During the study, the blood ChE activities of two mixer-loaders decreased and dialkyl phosphate levels of 2.4 ppm were found in the urine of one worker. An investigation indicated that the workers had failed to use the provided closed-transfer system. Airborne residues from liquid pesticides during closed transfer and mixing-loading averaged 5.8 microgram/m3, while residues from dusty powders averaged 152 microgram/m3. Airborne residues during ground application averaged 3.7 microgram/m3 during the workday. Mevinphos residues on cloth patches averaged 0.2 microgram/cm2.

Agricultural Workers' Diseases↗
PubMed1980

Genetic characteristics of hemophilia A in Chile.

A genetic and demographic study of 40 kindreds (113 cases) with hemophilia A, representing one quarter of all Chilean cases is reported. Only 10 sporadic cases were found. Segregation analysis of progeny from matings Aa X AY showed p = 0.2206 +/- 0.043. Fertility of 59 obligatory carriers was 3.88 children per mother with a mean age of 49.9 years, a figure higher than the mean of a control population, 3.36. The fertility of hemophiliacs was found to be 2.3 compared with their normal sibs with 3.15 children per couple. Life expectancy at birth in hemophiliacs was 22.4 years, compared with 28.1 for their normal brothers, 34.4 for their sisters and 58.5 and 64.6 for males and females in the general population. Mean relative fitness was calculated as 0.45 and the prevalence of hemophilia A in Chile as 1 case among 13,500 males. A preliminary estimate of the mutation rate was 1.35 X 10-5, within expected ranges. During the last 10 years, family planning and modern treatment with cryoprecipitates have increased the mean age of living hemophiliacs from 12.7 up to 22.7 years, and life expectancy from 15.6 to 22.4 years. Probably relaxation of natural selection will account for a possible increase of new cases of hemophilia A in the near future.

Adult↗
PubMedDate not supplied

Acceptability of a human papillomavirus (HPV) trial vaccine among mothers of adolescents in Cuernavaca, Mexico.

BACKGROUND: A scenario that must be considered when testing prophylactic human papillomavirus (HPV) vaccines in teenagers is the parents' acceptability of their daughters' participation in the study. METHODS: A survey was carried out in a random sample of 880 women between the ages of 15 and 49 years in the metropolitan area of Cuernavaca, Mexico. These women were interviewed to obtain information concerning their knowledge of risk factors for cervical cancer and their perception of the usefulness of vaccines. Afterward, they were provided with information on the main risk factors for cervical cancer and the future availability of a human papillomavirus (HPV) vaccine to prevent cervical cancer. Finally, we explored, with parents, the possible acceptability of an HPV vaccine for their teenaged daughters. The degree of acceptability and its association with a series of sociodemographic and reproductive factors were assessed. RESULTS: The respondents had little knowledge regarding the etiology of cervical cancer. Only 1.9% said that the principal risk factor was infection with HPV; however, 84.2% were aware of the usefulness of vaccines and 83.6% of the women indicated that they would allow their daughters to participate in a trial to evaluate the effectiveness of an HPV vaccine that helps prevent cervical cancer. The main factor associated with the acceptance of a possible vaccine against HPV was the knowledge of the usefulness of vaccines [odds ratio (OR) = 6.5, 95% confidence interval (CI) 5.2-8.2]. Likewise, a history of two or more sexual partners (OR = 2.2, 95% CI 1.3-3.6) increased acceptability. Acceptance was not associated with the number of live births (never vs. ever OR = 0.9, 95% CI 0.3-2.1). There were 525 women with children over the age of 10 years (59.6%); prevalence of acceptability among these women was 80.1%, not statistically different from the remainder of the sample (p >0.05). CONCLUSIONS: Acceptance of a potential HPV vaccine was high in this sample of Mexican women. Initiation of HPV vaccine clinical trials and immunization campaigns that target school children and/or teenagers who are not sexually active should include educational programs aimed at mothers of these individuals. Knowledge of the benefits of a preventive vaccine as well as the etiology and risk factors of cervical cancer should be emphasized.

Adolescent↗
PubMedDate not supplied

Development of an HIV educational needs assessment tool.

The learning needs of persons with HIV/AIDS continue to grow more complex as new treatments are developed and HIV disease shifts from being a terminal to a chronic illness. Clinicians could use a simple tool to help them to focus on what clients think is important to know about living with HIV/AIDS. This article describes the development of the HIV Educational Needs Assessment Tool (HENAT). HIV+ persons (N = 363) who were receiving health care in a variety of ambulatory and institutional settings participated in this research during 1990 and 1993-1994. Factor analysis was used to shorten the instrument into a form that could be used in any nurse/client interaction. Principal axis factor extraction and varimax rotation deleted 16 items. The remaining 34 items were grouped into six factors: Treatments, Entitlements, Relationships, Preventing Infections, Social Support, and Working. Cronbach's alphas were computed and results ranged from .70 to .88. Two month test-retest correlations for a subset of participants (n = 195) ranged from .54 to .67. HENAT can be used (a) to examine differences in perception of learning needs between clients with HIV disease and their health care providers, (b) to measure shifts in learning needs over time, (c) to relate HIV-specific learning needs to length of time living with HIV disease, (d) to give clients an opportunity to assess their learning needs, and (e) as part of a larger intervention study that evaluates the effectiveness of patient education.

Adult↗