Detection and estimation of the increasing trend of cancer incidence in relatively small populations.

BACKGROUND: Detection and estimation of trends in cancer incidence rates are commonly achieved by fitting standardized rates to a joinpoint log-linear regression. The efficiency of this approach is inadequate when applied to a relatively low levels of incidence. We compared that approach with the Cuscore test with respect to detecting a log-linear increasing trend of chronic myelomonocytic leukemia (CMML) in datasets simulated to match a province of about 700,000 inhabitants. METHODS: For better efficiency, we replaced the standardized rate as the dependent variable with a continuous statistic that reflects the inverse of the standardized incidence ratio (SIR). Both procedures were applied to datasets simulated to match published results in the Girona Province of Spain. We also present the use of the q-interval in displaying the temporal pattern of the events. This approach is demonstrated by analyses of CMML diagnoses in Girona County (1994-2008). RESULTS: The Cuscore was clearly more efficient than regression in detecting the simulated trend. The relative efficiency of the Cuscore is likely to be maintained in even higher levels of incidence. The use of graphical displays in providing clues regarding interpretation of the results is demonstrated. CONCLUSIONS: The Cuscore test coupled with visual inspection of the temporal pattern of the events seems to be more efficient than regression analysis in detecting and interpreting data suspected to be at elevated risk. A confirmatory analysis is expected to weed out 75% of the superfluous significant results.

Low levels of alpha7-nicotinic acetylcholine receptor mRNA on peripheral blood lymphocytes in schizophrenia and its association with illness severity.

BACKGROUND: There is evidence that the nicotinic alpha7-acetylcholine receptor (alpha7-AChR) is involved in the pathophysiology of schizophrenia. Several neurotransmitter receptors, including alpha7-AChR, have been demonstrated on peripheral blood lymphocytes (PBL) and it has been suggested that these peripheral receptors may reflect corresponding brain receptors. OBJECTIVE: In this study we compare alpha7 mRNA expression in PBL between schizophrenia patients and control individuals in order to determine whether any correlation exists between alpha7 mRNA expression in PBL and severity of schizophrenia. In addition, the isoforms of alpha7-AChR expressed are identified. METHOD: Peripheral venous blood samples were collected from individuals with schizophrenia (n = 44) and from healthy subjects (n = 16). Symptomatology and illness severity were assessed using standard clinical psychiatric evaluation scales. RNA was prepared from isolated lymphocytes and alpha7 mRNA was measured by RT-PCR. RESULTS: We observed a significantly lower level of alpha7 mRNA on PBLs of schizophrenia patients in comparison with healthy controls (p < 0.00). A tendency to a negative correlation was noted between the CGI score, reflecting illness severity, and the alpha7-subunit gene expression. CONCLUSION: Observations confirm that the alpha7 mRNA in PBL represents the duplicated alpha7-AChR gene rather than the classic alpha7-AChR gene. Our study observations further substantiate the involvement of alpha7-AChR in the pathophysiology of schizophrenia and, while preliminary, indicate that the alpha7-AChR may be expressed and be readily measured in the peripheral blood circulation.