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Biomedical subjects

S C Weller

Publications and source records attributed to S C Weller.

At least 19 recordsLinked to original sources
PubMed1999

Latino beliefs about diabetes.

OBJECTIVE: To describe Latino beliefs about diabetes and assess heterogeneity in beliefs across different groups. RESEARCH DESIGN AND METHODS: This study comprised a survey of 161 representative Latino adults from four diverse communities: Hartford, Connecticut; Edinburg, Texas; Guadalajara, Mexico; and rural Guatemala. A 130-item questionnaire covered causes symptoms, and treatments for diabetes. Information on demographics and acquaintanceship with someone with diabetes was also collected. The cultural consensus model was used to analyze the variation in responses to determine whether the degree of consistency within and between samples was sufficient to warrant aggregation and description as a single set of beliefs. RESULTS: Homogeneous beliefs were present within each of the four samples. Although variability in responses increased significantly from Connecticut to Guatemala (P < 0.00005), there was significant agreement between samples on the answers (P < 0.0005). Answers tended to be concordant with the biomedical description of diabetes. Greater acculturation, higher educational attainment, and higher diabetes prevalence were associated with greater cultural knowledge about diabetes. In Connecticut, greater knowledge correlated with longer mainland U.S. residency (P < 0.05). In Mexico, those with average educational attainment knew more (P < 0.05). Finally, average knowledge levels were higher in communities with greater diabetes prevalence. CONCLUSIONS: The cultural consensus model facilitated assessment of cultural beliefs regarding diabetes and diabetes management. Overall, Latino cultural beliefs about diabetes were concordant with the biomedical model. Variation in responses tended to characterize less knowledge or experience with diabetes and not different beliefs.

Adult↗
PubMed1999

Rapid ethnographic assessment of breastfeeding practices in periurban Mexico City.

Before carrying out a breastfeeding promotion programme in a periurban area of Mexico City, we conducted a rapid ethnographic study to determine the factors associated with absence of exclusive breastfeeding. The responses to pilot interviews were used to develop a standardized questionnaire regarding reasons for infant feeding choice, sources of advice, and barriers to breastfeeding. We interviewed a random sample of 150 mothers with a child < 5 years of age; 136 (91%) of them had initiated breastfeeding; but only 2% exclusively breastfed up to 4 months. The mothers consistently stated that the child's nutrition, health, growth, and hygiene were the main reasons for the type of feeding selected; cost, comfort, and the husband's opinion were less important. Physicians were ranked as the most important source of advice. Reduction or cessation of breastfeeding occurred on the doctor's advice (68%); or when the mothers encountered local folk illnesses such as "coraje" (52%) or "susto" (54%), which are associated with anger or fright; or had "not enough milk" (62%) or "bad milk" (56%); or because of illness of the mother (56%) or child (43%). During childhood illnesses and conditions, breastfeeding was reduced and the use of supplementary foods was increased. This study emphasizes the importance of cultural values in infant feeding choices, defines specific barriers to breastfeeding, and provides a basis for interventions to promote exclusive breastfeeding in the study population.

Adolescent↗
PubMed1999

Consensus theory model of AIDS/SIDA beliefs in four Latino populations.

To describe Latino beliefs about AIDS (SIDA), Latino adults were sampled at two U.S. sites (Connecticut and Texas) and two international sites (Mexico and Guatemala). A 125-item questionnaire covered risk factors, symptoms, treatments, and sequellae of AIDS. The cultural consensus model was used to determine the cultural beliefs for each sample. Responses from 161 people indicated that a single set of beliefs was present at each site and that beliefs were shared across sites. Comparison of answers between samples indicated high agreement (p < .0007). The proportion of shared beliefs, however, decreased significantly between samples: .68 in Connecticut, .60 in Texas, .51 in Mexico, and .41 in Guatemala (p < .05). The proportion of positive answers similarly decreased from Connecticut to Guatemala (p < .001). Beliefs were stronger and more detailed in the higher prevalence areas. Furthermore, Latino beliefs tended to converge on biomedical beliefs about the disease.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Predicting treatment-seeking behavior in Guatemala: a comparison of the health services research and decision-theoretic approaches.

This study attempts to identify and describe factors associated with the choice of a health care source in rural Guatemala. Because of limited choice options, rural Guatemala makes an excellent location for studying the factors that affect utilization patterns. Illness case histories were collected from a random sample of 270 households in six villages. Then, two different methodological approaches were used to predict treatment actions. First, a sociobehavioral model, which encompasses enabling, predisposing, and need factors, was used to predict treatment choices. Using discriminant analysis we identified factors associated with the use of home remedies, a pharmacy, the health post, a physician, or folk healer. In a second, parallel study, descriptive interviews were used to identify important factors in choosing a treatment strategy. From these interviews, and from responses to hypothetical illness cases, we developed a decision model of treatment actions. Both models were tested against the set of illness cases. Results indicate that both approaches identify similar variables (especially, severity), although selection of variables through the multivariate analysis was much more successful in predicting treatment actions.

Adolescent↗
PubMed1996

An asthma self-management program for children, including instruction in peak flow monitoring by school nurses.

A randomized trial of an instructional method was conducted in which school nurses taught children asthma self-management principles and skills, including peak flow monitoring, in 20-min, individual sessions over an 8-week period. Thirty-six children participated. An intervention group of 18 children received the teaching sessions. A control group of 18 children received regular care by the nurses, but no teaching sessions. The sample included 64% boys, 69% African-Americans, and 69% Medicaid recipients. The average age of subjects was 10.2 years. The two groups were demographically similar, but despite random assignment, the control group had a significantly earlier age of onset of asthma and tended to have had more asthma attacks in the preceding year. These factors were statistically controlled in outcome analyses. Results of group comparisons showed no significant differences in the number of postintervention emergency room visits and days absent from school. However, nurses reported that children who practiced breathing exercises had less anxiety during exacerbations, and the nurses' knowledge of the children's baseline peak expiratory flow rates facilitated care of the children. Nurses expressed the opinion that the individual sessions with students might be useful in motivating them to participate effectively in later group sessions. The intervention was well accepted by students, parents, and nurses. We believe that this intervention is promising as a practical, low-cost approach to enhancing children's asthma self-management skills and warrants further testing in a larger sample, with the intervention conducted over a longer period.

Absenteeism↗
PubMed1995

Knowledge, beliefs, and practices in relation to malaria transmission and vector control in Guatemala.

As part of an effort to involve community members in malaria control activities, we studied knowledge, beliefs, and practices of residents of both the Pacific coastal plain and northeastern Guatemala related to malaria transmission and Anopheles albimanus control. Most residents recognized the role of mosquitoes in malaria transmission, but few knew how mosquitoes acquired their infections or understood the risk of having an untreated person in their midst. If this were more widely known, residents might put greater pressure on infected patients to seek timely and appropriate antimalarial treatment. Seventy-three percent of families owned one or more bed nets; however, even though most informants believed that bed nets help protect against malaria, the major reason for using them was to prevent nuisance mosquito bites. It is concluded that efforts should be made to promote bed net use by seeking ways to make them more affordable and by emphasizing their effectiveness as a barrier to nuisance mosquitoes. Although residents have a very positive opinion of the National Malaria Service spray teams, it is proposed that cooperation might be improved if malaria workers would emphasize the fact that house spraying reduces the numbers of nuisance mosquitoes and other pest insects, rather than focusing solely on malaria prevention, which most informants believed was less important. This study emphasizes the importance of understanding community beliefs and practices when planning or evaluating vector control activities.

Adult↗
PubMed1995

Predictors of lead stores in male veterans.

Thirty-two male veterans participated in a study to determine cumulative lead exposure in an urban population. Subjects were chosen on the basis of blood pressure status in order to attempt to compare lead exposure between patients with and without hypertension. Patients currently enrolled in hypertension clinic and on treatment were recruited and matched with controls for age, race, and socioeconomic status. Each subject underwent provocative chelation via slow intravenous infusion of CaNa2 EDTA and 6-h urinary lead measurement and completed an interviewer-administered questionnaire. Twenty blacks and 12 whites participated, with a median age of 52 years (range: 27 to 72). Urinary lead excretion ranged from below detection limits to frankly toxic levels in an individual with heavy moonshine ingestion. Lead levels were higher than reported in other non-workplace populations. The distribution of lead values was skewed, as expected, with a median excretion of 75 mcg lead/6 h (corresponding to a median 24 degrees post-chelation urinary lead excretion of 286 mcg) and modal values between 50 and 75 micrograms lead. Levels of 95 mcg lead/6 h (corresponding to 24 degrees levels of 333 mcg lead) and above were considered "high" (N = 11) and the remainder were "low" (N = 21). Among those able to recall various characteristics of their first childhood dwellings, the presence of flaking paint in a multiple family dwelling was strongly associated with "high" lead excretion (X2 = 9.32, p = 0.009). Hypertensives excreted slightly more lead than nonhypertensives, although the difference was not statistically significant in this small sample. Lead excretion was not associated with current (treated) blood pressure determinations among hypertensives. However, lead excretion was associated with systolic pressure as recorded on entry to the hypertension clinic (N = 21, R2 = 0.24, p = 0.03).

Adult↗
PubMed1994

Selection for kanamycin resistance in transformed petunia cells leads to the co-amplification of a linked gene.

A cell suspension culture was established from a transgenic petunia (Petunia hybrida L.) plant which carried genes encoding neomycin phosphotransferase II (nptII) and beta-glucuronidase (uidA, GUS). Two selection experiments were performed to obtain cell lines with increased resistance to kanamycin. In the first, two independently selected cell lines grown in the presence of 350 micrograms/ml kanamycin were eight to ten-fold more resistant to kanamycin than unselected cells. Increased resistance was correlated with amplification of the nptII gene and an increase in nptII mRNA levels. Selection for kanamycin resistance also produced amplification of the linked GUS gene, resulting in increased GUS mRNA levels and enzyme activity. Selected cells grown in the absence of kanamycin for twelve growth cycles maintained increased copy numbers of both genes, and GUS enzyme activity was also stably overexpressed. In a second selection experiment, a cell line grown continuously in medium containing 100 micrograms/ml kanamycin exhibited higher nptII and GUS gene copy numbers and an increase in GUS enzyme activity after eleven growth cycles. In this cell line, amplification of the two genes was accompanied by DNA rearrangement.

Cells, Cultured↗
PubMed1994

Qualities of an ideal volunteer community malaria worker: a comparison of the opinions of community residents and national malaria service staff.

Since the late 1950s, most malaria surveillance and treatment in rural areas of Latin America has been carried out by networks of unpaid community malaria workers, known as Volunteer Collaborators, who are selected and supervised by staff of the national malaria services (NMSs) in each country. In spite of the free and readily accessible antimalarial treatment available at these Volunteer Collaborator posts, many residents continue to seek treatment elsewhere and in most cases take doses of antimalarials that are insufficient to cure their infections. To identify ways in which the Volunteer Collaborator Network could be made more attractive to residents and to improve the process of selection of new workers, we asked community residents and Guatemalan NMS workers to rank order, according to their importance, 11 qualities or characteristics of an 'ideal' volunteer malaria worker. Community residents preferred someone who is available to take care of patients at all times of the day, is a responsible person, and has a general knowledge of medicine. No significant differences were noted in the rank orders of male and female residents or literate and illiterate residents. National Malaria Service workers also preferred someone who takes care of patients at all times of the day, even when busy. In addition, they wanted individuals who recognize the importance of their work as a Volunteer Collaborator, but choosing volunteers who had a general knowledge of medicine was not important. By modifying the procedures used to select Volunteer Collaborators so as to identify candidates with the qualities preferred by residents, it should be possible to increase acceptance and improve the performance of these volunteer workers.

Adolescent↗
PubMed1994

Obesity, school performance and behaviour of black, urban elementary school children.

Nutritional status, school performance and behaviour were assessed in a group of black, inner-city school children. Thirty-five per cent of the children were obese by triceps skinfold thickness criteria. The primary care taker's responses to the Child Behavior Checklist (CBCL) and the hyperactivity subscale of the Conners' Parent's Questionnaire indicated that the obese children were more likely to have abnormal scores. On the CBCL subscale scores, obese girls had a significantly higher 'sex problems' score. Although the other subscale scores were not significantly different, there was a significant trend for obese boys and girls to score higher on the CBCL subscale scores. In addition, the proportion of obese children placed in special education or remedial class settings was twice that for non-obese children. These results add to the limited information available concerning obese black children, and are consistent with previous findings suggesting subtle behaviour differences in obese children.

Black or African American↗
PubMed1993

A meta-analysis of condom effectiveness in reducing sexually transmitted HIV.

Before condoms can be considered as a prophylaxis for sexually transmitted human immunodeficiency virus (HIV), their efficacy must be considered. This paper reviews evidence on condom effectiveness in reducing the risk of heterosexually transmitted human HIV. A meta-analysis conducted on data from in vivo studies of HIV discordant sexual partners is used to estimate the protective effect of condoms. Although contraceptive research indicates that condoms are 87% effective in preventing pregnancy, results of HIV transmission studies indicate that condoms may reduce risk of HIV infection by approximately 69%. Thus, efficacy may be much lower than commonly assumed, although results should be viewed tentatively due to design limitations in the original studies.

Adult↗
PubMed1993

Empacho in four Latino groups: a study of intra- and inter-cultural variation in beliefs.

It is usually impossible to know if reported differences between cultures are due to cultural differences or due to a difference in the methods used to study the cultures. This paper describes a collaborative, multisite study using a shared methodology to study intra- and inter-cultural variation in beliefs. A series of standard interview schedules were used to study Latin American beliefs about empacho in Guatemala, Mexico, and in the United States (Mexican-Americans and Puerto Ricans). Results showed consistency in beliefs about empacho both within and between the four samples.

Adolescent↗
PubMed1993

A serine-to-threonine substitution in the triazine herbicide-binding protein in potato cells results in atrazine resistance without impairing productivity.

A mutation of the psbA gene was identified in photoautotrophic potato (Solanum tuberosum L. cv Superior x U.S. Department of Agriculture line 66-142) cells selected for resistance to 6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine (atrazine). Photoaffinity labeling with 6-azido-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine detected a thylakoid membrane protein with a M(r) of 32,000 in susceptible, but not in resistant, cells. This protein was identified as the secondary quinone acceptor of photosystem II (QB) protein. Atrazine resistance in selected cells was attributable to a mutation from AGT (serine) to ACT (threonine) in codon 264 of the psbA gene that encodes the QB protein. Although the mutant cells exhibited extreme levels of resistance to atrazine, no concomitant reductions in photosynthetic electron transport or cell growth rates compared to the unselected cells were detected. This is in contrast with the losses in productivity observed in atrazine-resistant mutants that contain a glycine-264 alteration.

Amino Acid Sequence↗
PubMed1993

Differential activation and classification of cutaneous afferents in the rat.

1. A total of 312 cutaneous afferent units identified in the rat foot as belonging to one of nine major types of sensory receptors were included in the present study. A natural stimulus set was defined to differentiate optimally among those receptor types according to the distinguishing response patterns that it produced. It included air puffs, 30- and 300-Hz sinusoids, 200-mN force indentation of the skin, 1.2- and 6-N compressions of a skin fold, cooling the skin by 5 and 20 degrees C, warming by 5 degrees C, and heating by 15 degrees C. 2. The responses to predefined stimuli of 188 units were subjected to multivariate statistical analyses. The responses of an individual unit were measured as the number of impulses evoked by 10 stimuli, each lasting 10 s. Additionally, the number of impulses occurring for 5 s after withdrawal of a 200-mN indentation (1 of the 10 stimuli) was counted. 3. In discriminant analysis, the 11 stimulus variables predicted fairly correctly the grouping of afferent units into nine predetermined receptor categories (175 of 188, 93.1%), indicating a powerful ability to discriminate among different receptor types. Using hierarchical cluster analysis, afferent unit data described by 11 variables were divided into clusters that well represented prior receptor categories (170 of 188, 90.4%), suggesting the reliable application of this procedure to the classification of newly recorded cutaneous sensory receptors. 4. Eleven variables were then reduced to 7 on the basis of the results of factor analysis (95% of variance accounted for). The seven variables corresponded to 1.2-N compression, heating the skin by 15 degrees C, cooling the skin by 20 degrees C, 30- and 300-Hz sinusoids, withdrawal of a 200-mN indentation, and air puffs. 5. The seven selected variables correctly assigned afferent units into five modality-based categories in the discriminant solution (177 of 188, 94.1%). In the cluster solution, afferent units described by the seven selected variables were divided into clusters, most of whose members were modality specific (176 of 188, 93.6%). 6. The results indicate that cutaneous receptors can be divided into modality-specific groups according to similarities in their responses to seven stimulus variables. It is proposed that the stimulus set developed here and multivariate statistical methods can be used as powerful tools for the functional classification of central somatosensory neurons.

Afferent Pathways↗
PubMed1993

Acculturation and compliance with medical therapy.

Lack of compliance with medical therapy is a major clinical problem. We undertook a study to determine whether degree of acculturation to mainland U.S. culture was predictive of compliance in Puerto Rican families having a child with asthma. A questionnaire was administered to parents of Puerto Rican asthmatic children attending an asthma clinic and taking oral theophylline as part of their medical management. The questionnaire included items concerning medical, socioeconomic, and cultural variables, as well as a standardized instrument devised to measure degree of acculturation. Compliance was measured by a serum theophylline level obtained at the time of the visit. Families were divided into compliant (n = 15) and noncompliant (n = 13) groups based on their child's serum theophylline determination. There was a significant difference in mean acculturation scores between compliant and noncompliant groups (p = .008). Those in the complaint group had scores indicative of a style of acculturation that integrated aspects of both "Anglo" and Puerto Rican lifestyles. Those in the noncompliant group had scores indicative of a less acculturated lifestyle. The findings of this study show that degree of acculturation is a predictor of compliance with medical therapy in mainland Puerto Ricans. Additional studies with other cultural groups are needed, as well as other studies incorporating acculturation into a multivariate model of compliance.

Acculturation↗
PubMed1992

Knowledge and beliefs about malaria on the Pacific coastal plain of Guatemala.

Surveys of residents of the Pacific coast of Guatemala revealed a lack of knowledge and many misconceptions about the transmission and treatment of malaria, which could adversely affect malaria control measures and antimalarial therapy. Although mosquitoes are known to play an important role in malaria transmission and are thought to become infected by biting individuals with malaria, 75% of people interviewed believe that the mosquitoes can also acquire infections from contaminated water or by biting snakes and frogs. Furthermore, most residents believe that malaria can be acquired in other ways, such as by bathing too frequently or by drinking unboiled water. Although self-treatment of malaria with oral and injectable drugs purchased at stores and pharmacies is very common, less than 10% of the respondents were aware of the correct curative dose of chloroquine. Chloroquine injections are preferred to tablets and believed to be approximately three times as potent as tablets of the same concentration. Nearly two-thirds of the interviewees believed that pregnant and lactating women with malaria should avoid the use of chloroquine because it may cause a spontaneous abortion or dry up breast milk. Similar surveys of National Malaria Service workers and village malaria workers revealed higher levels of knowledge, although the village workers had many misconceptions about malaria transmission. An educational campaign directed at correcting some of these misconceptions should result in more appropriate self-treatment of malaria and greater acceptance by residents of personal protection methods and vector control and drug treatment programs.

Adult↗
PubMed1992

OSHA's bloodborne pathogens rule an opportunity/threat.

If you supply healthcare linen, OSHA's new ruling comes with a price tag, but it may be a marketing boon as well. The costs of compliance are high--about $1.19 million annually. One of the most costly and important parts of the ruling is the required employer-paid hepatitis B vaccination of employees. But behind the costs, there's good news for the textile rental industry. The opportunity to serve small medical facilities and nursing homes as well as hospitals with reusable healthcare garments could create a revenue source estimated to be at least $177 million a year.

Blood↗