Assessing the health impact of interventions for baker's allergy and asthma in supermarket bakeries: a group randomised trial.

PURPOSE: To assess the impact of an intervention for baker's allergy and asthma in supermarket bakeries. METHODS: A group randomised trial conducted in 31 bakeries (n = 337 bakers) that were randomly assigned to one of two intervention groups (n = 244 bakers) and a control group (n = 93 bakers). Health data collected prior to and 1-year after the intervention included information obtained from an ECRHS questionnaire; tests for atopy and serum-specific IgE to cereal flours; fractional exhaled nitric oxide (FeNO). Data from the two intervention groups were combined to form one intervention group for purposes of the statistical analysis. RESULTS: At 1 year of follow-up, the incidence and level of decline of work-related ocular-nasal and chest symptoms, sensitisation status and elevated FeNO (FeNO > 25 ppb) was similar in both intervention and control groups. The mean FeNO difference was also similar across both groups (2.2 ppb vs 1.7 ppb, p = 0.86). In those with FeNO > 25 ppb at baseline, the decline was greater in the intervention compared to control group (16.9 ppb vs 7.7 ppb, p = 0.24). Multivariate logistic regression models (adjusting for smoking, baseline sensitisation to cereal flour, baseline FeNO > 25 ppb) did not demonstrate an appreciable FeNO decline (≥ 10%) in the intervention compared to control group. However, stratification by the presence of work-related ocular-nasal symptoms in bakers at baseline demonstrated a significant FeNO decline (≥ 10%) in the intervention compared to the control group (OR 3.73, CI 1.22-11.42). CONCLUSION: This study demonstrates some evidence of an intervention effect on FeNO 1 year after an intervention, particularly in bakers with work-related ocular-nasal symptoms.

D1 receptor alleles predict PET metabolic correlates of clinical response to clozapine.

A goal of pharmacogenetics is to clarify associations between allelic variation and risk factors in psychiatric illness. We report changes in regional brain metabolism based on dopamine alleles. Treatment-resistant schizophrenic subjects were positron emission tomography scanned with 18F-fluorodeoxyglucose after 5 weeks each of placebo and clozapine treatment. Significant regional brain metabolic effects were found for the D1 receptor genotypes (P < 0.05), adjusted for multiple comparisons. Metabolic decreases for the 2,2 genotype but not the 1,2 genotype were observed in all major sectors of the brain, with the exception of the ventral parts of the caudate and putamen. Frontal, temporal, parietal, and occipital neocortices showed decreased metabolism as did the cingulate juxta-allocortex and the parahippocampal allocortex. Decreases were also observed in the thalamus, amygdala, and cerebellum bilaterally. No significant metabolic differences by genotype were observed for D3, 5HT(2A), and 5HT(2C) polymorphisms. In terms of clinical response, the DRD1 2,2 genotype significantly improved with clozapine treatment, demonstrating a 30% decrease in the Brief Psychiatric Rating Scale positive symptoms in contrast to a 7% worsening for the 1,2 genotype (P < 0.05). In this preliminary study, brain metabolic and clinical response to clozapine are related to the D1 receptor genotype.

Association of the MscI polymorphism of the dopamine D3 receptor gene with tardive dyskinesia in schizophrenia.

In 112 schizophrenic patients previously treated with typical neuroleptics, we investigated the putative role of the dopamine D3 receptor gene (DRD3) in tardive dyskinesia (TD). Patients were assessed for TD severity using the Abnormal Involuntary Movement Scale (AIMS) and were subsequently genotyped for the MscI polymorphism that identifies a serine to glycine substitution in DRD3. A modified analysis of covariance model, which incorporated several clinical risk factors for TD, was utilized to detect differences in TD severity among the various genotypic groups. The glycine allele of DRD3 was found to be associated with typical neuroleptic-induced TD (F[2,95] = 8.25, p < .0005). Higher mean AIMS scores were found in patients homozygous for the glycine variant of the DRD3 gene, as compared to both heterozygous and serine homozygous patients. Although replication is necessary, this finding supports a role for the dopamine D3 receptor in the pathogenesis of TD.

Investigation of dopamine system genes in obsessive-compulsive disorder.

Evidence from anatomical, pharmacological, and animal studies on the involvement of the dopamine system in obsessive-compulsive disorder (OCD) is mounting. This, along with evidence for a genetic diathesis provided by family and twin studies, prompted us to conduct genetic association studies of dopamine system genes in OCD. We genotyped OCD patients (n > 100) and matched controls for four loci: (1) a 40-base-pair repeat in the dopamine transporter gene; (2) the TaqIA polymorphism and the serine/cysteine variation in the D2 dopamine receptor gene; (3) an MscI polymorphism in the D3 dopamine receptor gene; and (4) a 48-base-pair repeat in the D4 dopamine receptor gene. Significant differences in allele frequencies were found between patients and controls for the D4 receptor gene, although replication is required with family-based controls before any conclusions can be entertained. This study represents the first comprehensive assessment of the roles of dopamine system genes in OCD.

Serotonin subtype 2 receptor genes and clinical response to clozapine in schizophrenia patients.

Using a pharmacogenetic approach in 185 schizophrenics who have been prospectively assessed for clozapine response, we have examined the hypothesis that polymorphisms in the 5-HT2A (HTR2A), and 5-HT2C (HTR2C) genes are involved in its variable response. A-1438 A-->G polymorphism in the putative promoter and a silent T-->C 102 substitution in HTR2A were in almost complete linkage disequilibrium, and neither was associated with response (T-->C. 102 allele: chi 2 = 0.02; 1 df, p = .90; genotype: chi 2 = 0.02, 2 df, p = .99). A his452tyr HTR2A polymorphism was found to be associated with clozapine response (his452tyr allele: chi 2 = 6.43, 1 df, p = .01 [p = .04, Bonferroni corrected]; genotype: chi 2 = 6.54, 2 df, p = .04 [p = .16, Bonferroni corrected]). No HTR2A haplotype was associated with response. Interethnic differences were observed in the frequencies of the cys23ser HTR2C polymorphism. This polymorphism was not significantly associated with response in either of the ethnic groups (Caucasian and African American genotype: chi 2 = 3.46, 2 df, p = .18; chi 2 = .31, 2 df, p = .86, respectively). Although replication is required, the overall results suggest that the his452tyr HTR2A polymorphism may be involved in clozapine response.

No evidence for association of dopamine D2 receptor variant (Ser311/Cys311) with major psychosis.

We investigated a variant of the dopamine D2 receptor gene (Ser311/Cys311 substitution) in Caucasian patients with schizophrenia (n = 273), delusional disorder (n = 62), bipolar I affective disorder (n = 63), and controls (n = 255). No evidence for association between the receptor variant and any of the diseases was found, even when patients with younger age-of-onset (< 25 years) were compared with controls. Furthermore, in a subgroup of schizophrenia patients whom we assessed for negative symptoms, those with the Cys allele did not differ from the remainder of the group. Also, the bipolar affective disorder patients with psychotic features did not show evidence for association with the receptor variant. Thus, our results do not provide evidence for an association between this D2 receptor variant and schizophrenia, or delusional disorder, or bipolar affective disorder.