The RNA integrity number (RIN) is often considered to be a critical measure of the quality of pos... more The RNA integrity number (RIN) is often considered to be a critical measure of the quality of postmortem human brains. However, it has been suggested that RINs do not necessarily reflect the availability of intact mRNA. Using the Agilent bioanalyzer and qRT-PCR, we explored whether RINs provide a meaningful way of assessing mRNA degradation and integrity in human brain samples by evaluating the expression of 3'-5' mRNA sequences of the cytochrome C-1 (CYC1) gene. Analysis of electropherograms showed that RINs were not consistently correlated with RNA or cDNA profiles and appeared to be poor predictors of overall cDNA quality. Cycle thresholds from qRT-PCR analysis to quantify the amount of CYC1 mRNA revealed positive correlations of RINs with amplification of full-length transcripts, despite the variable degree of linear degradation along the 3'-5' sequence. These data demonstrate that in postmortem human brain tissue the RIN is an indicator of mRNA quantity independ...
Data generated from an earlier study have suggested a model in which greater numbers of long, ver... more Data generated from an earlier study have suggested a model in which greater numbers of long, vertical, associative axons may occur in the anterior cingulate cortex of schizophrenic patients relative to control subjects. This hypothesis has now been tested using neuron-specific antibodies raised against the 200-kilodalton neurofilament subunit, a component of neuronal cytoskeleton, to immunostain axons of human postmortem cingulate cortex. A manual method for counting axons in the region of layer II and sublamina IIIA has been designed and applied blindly to parallel control and schizophrenic immunoprocessed specimens. The results show that there are 25% more vertical axons in the schizophrenic than in the control specimens. Preferentially higher numbers of both long vertical axons (62%) and axons associated with blood vessels (52%) have also been noted in the schizophrenic specimens. By contrast, the number of large-caliber horizontal axons was the same in the two groups; therefore, the greater number of vertical axons in schizophrenic specimens does not appear to represent a nonspecific effect. When these data are corrected for the effects of several confounding variables using analysis of covariance, the overall pattern of the results persists. These findings suggest the possibility that there might be an increase of associative inputs into the anterior cingulate cortex of schizophrenic patients, although it is not clear at present whether the differences noted, if replicative, may be primarily or perhaps only secondarily related to the disorder.
The suggestion that schizophrenia may involve a neurodegenerative process has emanated from the h... more The suggestion that schizophrenia may involve a neurodegenerative process has emanated from the highly replicated finding of ventricular enlargement in brain images of patients with this disorder. These investigations have provided a direct impetus for recent histopathologic studies seeking evidence of a neurodegenerative process in the brains of subjects with schizophrenia. Whereas most postmortem studies have reported the presence of atrophy and/or neuronal loss in several corticolimbic regions of subjects with schizophrenia, no quantitative study, to date, has detected an increase in the number of glial cells. For this reason the changes observed in postmortem schizophrenic brain are not consistent with a typical adult pattern of neuronal degeneration, such as that seen in Huntington's disease. Because several studies have reported various changes in layer II of the anterior cingulate, prefrontal, and entorhinal cortices, the histopathologic findings described are compatible with the idea that schizophrenia involves a disturbance of the "inside-out" migration or differentiation of cortical neurons that normally occurs during ontogenesis. A neurodevelopmental perturbation early in life could result in discrete alterations of corticolimbic circuitry that eventually contribute to the appearance of schizophrenic symptoms during adolescence and adulthood.
The RNA integrity number (RIN) is often considered to be a critical measure of the quality of pos... more The RNA integrity number (RIN) is often considered to be a critical measure of the quality of postmortem human brains. However, it has been suggested that RINs do not necessarily reflect the availability of intact mRNA. Using the Agilent bioanalyzer and qRT-PCR, we explored whether RINs provide a meaningful way of assessing mRNA degradation and integrity in human brain samples by evaluating the expression of 3'-5' mRNA sequences of the cytochrome C-1 (CYC1) gene. Analysis of electropherograms showed that RINs were not consistently correlated with RNA or cDNA profiles and appeared to be poor predictors of overall cDNA quality. Cycle thresholds from qRT-PCR analysis to quantify the amount of CYC1 mRNA revealed positive correlations of RINs with amplification of full-length transcripts, despite the variable degree of linear degradation along the 3'-5' sequence. These data demonstrate that in postmortem human brain tissue the RIN is an indicator of mRNA quantity independ...
Data generated from an earlier study have suggested a model in which greater numbers of long, ver... more Data generated from an earlier study have suggested a model in which greater numbers of long, vertical, associative axons may occur in the anterior cingulate cortex of schizophrenic patients relative to control subjects. This hypothesis has now been tested using neuron-specific antibodies raised against the 200-kilodalton neurofilament subunit, a component of neuronal cytoskeleton, to immunostain axons of human postmortem cingulate cortex. A manual method for counting axons in the region of layer II and sublamina IIIA has been designed and applied blindly to parallel control and schizophrenic immunoprocessed specimens. The results show that there are 25% more vertical axons in the schizophrenic than in the control specimens. Preferentially higher numbers of both long vertical axons (62%) and axons associated with blood vessels (52%) have also been noted in the schizophrenic specimens. By contrast, the number of large-caliber horizontal axons was the same in the two groups; therefore, the greater number of vertical axons in schizophrenic specimens does not appear to represent a nonspecific effect. When these data are corrected for the effects of several confounding variables using analysis of covariance, the overall pattern of the results persists. These findings suggest the possibility that there might be an increase of associative inputs into the anterior cingulate cortex of schizophrenic patients, although it is not clear at present whether the differences noted, if replicative, may be primarily or perhaps only secondarily related to the disorder.
The suggestion that schizophrenia may involve a neurodegenerative process has emanated from the h... more The suggestion that schizophrenia may involve a neurodegenerative process has emanated from the highly replicated finding of ventricular enlargement in brain images of patients with this disorder. These investigations have provided a direct impetus for recent histopathologic studies seeking evidence of a neurodegenerative process in the brains of subjects with schizophrenia. Whereas most postmortem studies have reported the presence of atrophy and/or neuronal loss in several corticolimbic regions of subjects with schizophrenia, no quantitative study, to date, has detected an increase in the number of glial cells. For this reason the changes observed in postmortem schizophrenic brain are not consistent with a typical adult pattern of neuronal degeneration, such as that seen in Huntington's disease. Because several studies have reported various changes in layer II of the anterior cingulate, prefrontal, and entorhinal cortices, the histopathologic findings described are compatible with the idea that schizophrenia involves a disturbance of the "inside-out" migration or differentiation of cortical neurons that normally occurs during ontogenesis. A neurodevelopmental perturbation early in life could result in discrete alterations of corticolimbic circuitry that eventually contribute to the appearance of schizophrenic symptoms during adolescence and adulthood.
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