Does Pet Ownership in Infancy Lead to Asthma or Allergy at School Age? Pooled Analysis of Individual Participant Data from 11 European Birth Cohorts

Objective

To examine the associations between pet keeping in early childhood and asthma and allergies in children aged 6–10 years.

Design

Pooled analysis of individual participant data of 11 prospective European birth cohorts that recruited a total of over 22,000 children in the 1990s.

Exposure definition

Ownership of only cats, dogs, birds, rodents, or cats/dogs combined during the first 2 years of life.

Outcome definition

Current asthma (primary outcome), allergic asthma, allergic rhinitis and allergic sensitization during 6–10 years of age.

Data synthesis

Three-step approach: (i) Common definition of outcome and exposure variables across cohorts; (ii) calculation of adjusted effect estimates for each cohort; (iii) pooling of effect estimates by using random effects meta-analysis models.

Results

We found no association between furry and feathered pet keeping early in life and asthma in school age. For example, the odds ratio for asthma comparing cat ownership with “no pets” (10 studies, 11489 participants) was 1.00 (95% confidence interval 0.78 to 1.28) (I² = 9%; p = 0.36). The odds ratio for asthma comparing dog ownership with “no pets” (9 studies, 11433 participants) was 0.77 (0.58 to 1.03) (I² = 0%, p = 0.89). Owning both cat(s) and dog(s) compared to “no pets” resulted in an odds ratio of 1.04 (0.59 to 1.84) (I² = 33%, p = 0.18). Similarly, for allergic asthma and for allergic rhinitis we did not find associations regarding any type of pet ownership early in life. However, we found some evidence for an association between ownership of furry pets during the first 2 years of life and reduced likelihood of becoming sensitized to aero-allergens.

Conclusions

Pet ownership in early life did not appear to either increase or reduce the risk of asthma or allergic rhinitis symptoms in children aged 6–10. Advice from health care practitioners to avoid or to specifically acquire pets for primary prevention of asthma or allergic rhinitis in children should not be given.     

A novel bioassay for herbicides used in wild oat control and for the assessment of their interactions with other xenobiotics

A bioassay is described which uses young oat seedlings to determine the activity of wild oat herbicides alone and in mixtures with other xenobiotics. Test solution (10 μl) was pipetted into the first leaf sheath of the oat seedlings, and 24 to 48 h later, basal shoot sections were removed and cultured for 24 h on agar. The inhibition of leaf growth from these sections, compared with control sections, was an assessment of herbicidal activity. Marked inhibition occurred when as little as 0–5 to 1 -0 μg of either diclofop-methyl or diclofop had been applied to each plant. Wheat and barley seedlings were unaffected by 12 μg of these herbicides, reflecting their known selectivity in cereal crops. The assay was used to evaluate the antagonisms of diclofop-methyl and diclofop activity by 2,4-D, MCPA, 2,3,6-TBA and also related ‘non-auxins’ (3,5-dichloro-phenoxyacetic acid and 2,3,5-TIBA). Diclofop-methyl was compatible with the 1-methylheptyl ester of (4-amino-3,5-dichloro-6-fluoro-2-pyridyl)oxyacetic acid (Dowco 433). The test allows the simultaneous examination of herbicidal responses and related metabolic changes in the oat tissue. As the procedure uses small amounts of chemical, it is suitable for ¹⁴C tracer studies and other investigations for v/hich research chemicals are not freely available. The use of the test with other species and other herbicides is discussed, and possible applications for screening for crop safeners and investigations on crop tolerance are suggested.     

Effects of N-cadherin overexpression on the adhesion properties of embryonic stem cells

Constitutive overexpression of N-cadherin in mouse embryonic stem cells led to marked changes in the phenotype and adhesion properties of these cells. The changes included the formation of smaller embryonic bodies, elevated mRNA and total protein levels of N-cadherin, and increased amounts of p120 catenin and connexin-43. N-cadherin cells exhibited decreased attachment to non-cell surfaces, while their adhesiveness to each other and to rat neonatal cardiomyocytes was significantly elevated. The findings suggest that N-cadherin overexpression can facilitate electromechanical integration of stem cells into excitable tissues with endogenously high levels of N-cadherin, such as the heart and brain.Key words: stem cells, cardiomyocytes, N-cadherin, connexin 43, gap junctions