The epidemiology of childhood asthma in Red Deer and Medicine Hat, Alberta.

OBJECTIVES: To document the prevalence of asthma among school-aged children in two Alberta communities, to understand host and indoor environmental factors associated with asthma, and to compare these factors between the two communities. DESIGN: A cross-sectional study with a nested, case-control follow-up. SETTING: Red Deer and Medicine Hat, Alberta. PATIENTS AND METHODS: Questionnaires were sent to families of children aged five to 19 years in Red Deer (n=5292) and Medicine Hat (n=5372) to identify children with current asthma. A random sample of 592 children with current asthma and 443 with no history of asthma constituted a case-control population; they were followed up by telephone to obtain responses to the European Respiratory Health Survey and, in children with current asthma, the Pediatric Quality of Life Questionnaire. RESULTS: Cross-sectional response rates were 84% and 73% for Red Deer and Medicine Hat, respectively. The prevalence of asthma was higher in Medicine Hat (17.0%) than in Red Deer (12.8%). In the follow-up study, factors associated with the presence of asthma were parental asthma or allergies, number of siblings, presence of cats, serious respiratory illnesses before five years of age, sex, age, presence of mould and/or mildew and use of a gas cooking stove. The presence of mould and/or mildew was a significant risk factor in Red Deer but not in Medicine Hat. CONCLUSIONS: Asthma prevalence among school children in Red Deer was consistent with recently published Canadian data; the prevalence in Medicine Hat was higher than expected, especially given the low relative humidity. Risk factor data are consistent with other studies in that parental asthma, especially maternal asthma, was a significant predictor of childhood asthma. Cats in the house (both communities) and environmental tobacco smoke (Medicine Hat only) were significantly less common among children with asthma, suggesting that preventive actions may have been taken in the homes of some children with asthma.

Cell-mediated and antibody immune responses to AIK-C and Connaught monovalent measles vaccine given to 6 month old infants.

Measles vaccination of infants younger than 1 year of age should be successful in populations with a high proportion of measles vaccinated mothers. Infants whose mothers were vaccinated are born with less maternal antibody which can interfere with vaccination compared with infants whose mothers had measles. AIK-C or Connaught (CLL) measles vaccine was given to 300 6 month infants born to mothers who had measles (group 1) or who were vaccinated against measles (group 2). Pre- and post-vaccination measles antibody was measured by EIA and PRN and cell mediated immunity (CMI) by blast transformation and production of interferon-gamma and interleukin-10. After vaccination, mean antibody level, seroconversion and blastogenesis were significantly lower for group 1 than group 2 (p < 0.05). Post-vaccination measles IgG was significantly higher for group 2 CLL vaccinees compared with group 2 AIK-C (p < 0.05); seroconversion rates were 73 and 63%, respectively. More than 93% of group 2 infants had elevated measles IgG after vaccination. About 89% of all children had some evidence of a blastogenic response. Lymphoproliferation correlated strongly with cytokine production and weakly with IgG. Not all seroresponders had a CMI response and vice versa. AIK-C and CLL vaccines induce strong measles specific T and B immunity in most 6 month infants of vaccinated mothers.

A comparison of alternate immunization regimes for measles in vaccinated populations.

Infants today lose maternal measles antibody sooner than in the past. This is related to demographic changes in maternal immunization. Data for rates of decay of maternal antibody and seroconversion after measles vaccination for infants born to naturally immune (Group 1) or vaccinated (Group 2) mothers have been used to evaluate two vaccination schedules: Regime 1, measles-mumps-rubella (MMR) at 1 year of age and Regime 2, monovalent measles at 6 months followed by MMR at 15 months of age. Regime 2 costs less because MMR can be administered at 15 months with the last pentavalent booster. Months of protection/1000 children aged 0-15 months (child-months of protection) were estimated for infant populations ranging from 0 to 100% Group 1 for Regimes 1 and 2. Regime 1 provides more child-months of protection only for 100% Group 1 populations. For the study population Regime 2 provided at least 17% more child-months of protection than Regime 1. Regime 2 provides increased medical and financial benefits in proportion to the number of Group 2 infants in the population and thus is ever more advantageous for today's increasingly vaccinated populations.

Kinetics of immunologic responses after primary MMR vaccination.

To study the kinetics of humoral as well as cellular immunity to measles and to test for associated immunosuppression 124 12 month old children were studied twice, before routine MMR and either 14, 22, 30, or 38 days after vaccination. Plaque reduction neutralization (PRN) titres were determined at these time points and lymphocytes were evaluated to identify changes in proportions of phenotype, their capacity to generate cytokines and to respond to blast transformation (BT) to measles hemagglutinin (HA), tetanus toxoid and Candida antigen. The PRN titre and BT to HA plateaued at 30 days and CD8+ and NK cells increased after immunization. Interleukin 2, 4, and 10 showed no significant changes. There was mild suppression of BT at 14 and 22 days post-immunization Interferon-gamma was the principal cytokine produced after primary measles immunization, suggesting primary measles immunization induces predominantly a TH1 type response.

Differential modulation of the immune response by breast- or formula-feeding of infants.

Spontaneous integrin expression on CD4+, CD8+ and CD19+ lymphocytes at 6 months was significantly lower in breastfed than formula-fed infants (p < 0.05). In another study of 59 formula-fed and 64 breastfed 12-month-old children blast transformation and cytokine production by lymphocytes, and T cell changes were measured before and after measles-mumps-rubella vaccination (MMR). Before vaccination, lymphocytes of breastfed children had lower levels of blast transformation without antigen (p < 0.001), with tetanus toxoid (p < 0.02) or Candida (p < 0.04), and lower interferon-gamma production (p < 0.03). Fourteen days after the live viral vaccination, only the breastfed children had increased production of interferon-gamma (p < 0.02) and increased percentages of CD56+ (p < 0.022) and CD8+ cells (p < 0.004). These findings are consistent with a Th1 type response by breastfed children, not evident in formula-fed children. Feeding mode has an important long-term immunomodulating effect on infants beyond weaning.

Measles vaccination of infants in a well-vaccinated population.

During outbreaks of measles, measles vaccine is recommended for infants considered to be at risk who are 6 months of age and older. In a prospective trial the serologic response to early measles immunization has been evaluated in 125 infants given monovalent measles vaccine at 6 to 8.5 months of age and measles-mumps-rubella at 15 months. The response to vaccination was measured by plaque reduction neutralization (PRN) assay and enzyme immunoassay. Infants were grouped by the mother's immunization history: natural immunity (n = 60, Group 1); killed followed by live, further attenuated vaccine (n = 22, Group 2); and live, further attenuated vaccine only (n = 43, Group 3). The prevaccination geometric mean titer (GMT) by PRN for Group 1 (GMT = 69) was significantly higher than that of Group 2 (GMT = 18) or 3 (GMT = 13). Seroconversion (4-fold increase in PRN titer) rates after monovalent vaccine were 31, 71 and 76% for Groups 1, 2 and 3, respectively. Seroconversion percentages were higher when measured 6 to 8 weeks after vaccination compared with 4 to 5 weeks. After measles-mumps-rubella > or = 97% of all infants had PRN titers > 120 and were measles IgG-positive by enzyme immunoassay. These data show that as demographics shift to a well-vaccinated maternal population and susceptibility in younger infants, measles vaccination before the currently recommended age will be effective.

Managing pain during mediastinal chest tube removal.

OBJECTIVE: To compare four analgesic regimens used in preparing patients for chest tube removal. DESIGN: Prospective, randomized, controlled multiple-group comparison. SETTING: Mid-atlantic university affiliated tertiary medical center. PATIENTS: 80 adult patients who underwent heart surgery and who had two mediastinal chest tubes. OUTCOME MEASURES: Subject's pain intensity rating on a 0 to 100 mm visual analog scale and subject's description of sensations blindly rated by six nurses. INTERVENTION: Before chest tube removal, subjects were medicated with either: (1) intravenous morphine sulfate (morphine), (2) intravenous morphine and subfascial angiocatheter lidocaine hydrochloride (lidocaine), (3) intravenous morphine and subfascial angiocatheter normal saline solution, or (4) subfascial angiocatheter lidocaine. RESULTS: Mean pain rating scores for groups 1, 2, 3, and 4 were 43.7 40.9, 36.4, and 38.1, respectively. Analysis of variance showed no significant difference between scores (p = 0.8948). The percentage of comments rated as "not bad at all" or "not bad" for groups 1, 2, 3, and 4 were 56%, 83%, 47% and 75%, respectively. Chi-square analysis showed a significant difference between ratings (p < 0.01). CONCLUSIONS: Blind ratings of subjects' descriptions of sensations suggest subfascial lidocaine may be useful in reducing discomfort during chest tube removal.

The use of the diary as a data collection technique.

The initiation of a research project requires many decisions, not the least of which is the selection of a method for data collection. This decision is, in large measure, guided by the nature of the research question which generally prescribes the selection of a strategy for data collection from among an array of possible alternatives. This article addresses the use of a diary for data collection. Although diaries have traditionally been used in social science and health research, their use in nursing research is more recent. The article begins with a brief discussion of the rationale for using the diary to gather data in a study of personal and professional caregiving. A brief review of the use of diaries in previous studies follows, along with a description of the use of a diary in the caregiving study and a discussion of the possible threats to high quality data as well as measures used to ensure the collection of high quality data. The article concludes with a discussion of the strengths and weaknesses of the diary and makes recommendations regarding its use in nursing research.

Reduced measles immunity in infants in a well-vaccinated population.

The recommended age for measles vaccination is based in part on information gathered when most mothers had natural measles. Nowadays many mothers have received measles vaccine. To assess this change measles antibody neutralization titers (NT) were determined for 278 mother-infant pairs. One hundred sixty-four mothers, born before 1958, likely had had natural measles (Group 1). Sixty mothers received one to three killed plus one attenuated measles vaccination (Group 2) and 54 received 1 attenuated measles vaccination only (Group 3). NT were determined for the mother and for the infant at birth and in the infant during the fourth and sixth months. Group 1 mothers and infants at every age had higher geometric mean NT than those in Groups 2 or 3 (P less than 0.05). By 7 months 65% of Group 1 infants and greater than 90% of Group 2 and 3 infants had an NT less than 1:10. The rate of antibody decay was significantly faster for Group 1 infants (P less than 0.05). Earlier vaccination in the infant should be considered.