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Bamberger CE, Ross RG. Combination beaker and filter for separating micro amounts of material*. J Microsc 2011. [DOI: 10.1111/j.1365-2818.1971.tb02289.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Affiliation(s)
- S. R. Hubbard
- a Great Yarmouth College of Further Education , Southtown , Great Yarmouth , NR31 0JU , England
- c University of East Anglia , Part-time research student
| | - R. G. Ross
- b School of Mathematics and Physics, University of East Anglia, University Plain , Norwich , NR4 7TJ , England
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Affiliation(s)
- R. G. Ross
- a School of Mathematics and Physics, University of East Anglia, University Village, Norwich, NOR 88C , Norfolk , England
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Mexal S, Berger R, Adams CE, Ross RG, Freedman R, Leonard S. Brain pH has a significant impact on human postmortem hippocampal gene expression profiles. Brain Res 2006; 1106:1-11. [PMID: 16843448 DOI: 10.1016/j.brainres.2006.05.043] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2005] [Revised: 04/24/2006] [Accepted: 05/03/2006] [Indexed: 10/24/2022]
Abstract
Studies of neurobiological disorders in the brain, including schizophrenia, rely on the use of postmortem brain tissues, in which an understanding of the effects of various pre- and postmortem variables on gene expression is critical. In several different brain regions, pH has been shown to have a large effect on postmortem brain gene expression patterns. One region that has not yet been evaluated in such studies is the hippocampus, a region often implicated in schizophrenia research. In the present study, we show that postmortem brain pH is similar across different brain regions. Brain pH accounted for greater variation in hippocampal gene expression profiles than any other parameter evaluated, including gender and schizophrenia. The predictive value of brain pH in an independent sample set was also greater than the disease, demonstrating that pH represents one of the most important control parameters in human postmortem gene expression studies in schizophrenia.
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Affiliation(s)
- S Mexal
- Department of Psychiatry, University of Colorado at Denver and Health Sciences Center, Mail Stop 8344, PO Box 6511, Aurora, CO 80045, USA
| | - R Berger
- Department of Psychiatry, University of Colorado at Denver and Health Sciences Center, Mail Stop 8344, PO Box 6511, Aurora, CO 80045, USA
| | - C E Adams
- Department of Psychiatry, University of Colorado at Denver and Health Sciences Center, Mail Stop 8344, PO Box 6511, Aurora, CO 80045, USA
| | - R G Ross
- Department of Psychiatry, University of Colorado at Denver and Health Sciences Center, Mail Stop 8344, PO Box 6511, Aurora, CO 80045, USA
| | - R Freedman
- Veterans Affairs Medical Research Center, Denver, CO 80220, USA; Department of Psychiatry, University of Colorado at Denver and Health Sciences Center, Mail Stop 8344, PO Box 6511, Aurora, CO 80045, USA
| | - S Leonard
- Veterans Affairs Medical Research Center, Denver, CO 80220, USA; Department of Psychiatry, University of Colorado at Denver and Health Sciences Center, Mail Stop 8344, PO Box 6511, Aurora, CO 80045, USA.
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Mexal S, Frank M, Berger R, Adams CE, Ross RG, Freedman R, Leonard S. Differential modulation of gene expression in the NMDA postsynaptic density of schizophrenic and control smokers. ACTA ACUST UNITED AC 2006; 139:317-32. [PMID: 16122832 DOI: 10.1016/j.molbrainres.2005.06.006] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2005] [Revised: 05/27/2005] [Accepted: 06/08/2005] [Indexed: 10/25/2022]
Abstract
Nicotine is known to induce the release of multiple neurotransmitters, including glutamate and dopamine, through activation of nicotinic receptors. Gene expression in the N-methyl-d-aspartate postsynaptic density (NMDA-PSD), as well as other functional groups, was compared in postmortem hippocampus of schizophrenic and nonmentally ill smokers and nonsmokers utilizing a microarray and quantitative RT-PCR approach. The expression of 277 genes was significantly changed between all smokers and nonsmokers. Specific gene groups, most notably genes expressed in the NMDA-PSD, were prevalent among these transcripts. Analysis of the interaction between smoking and schizophrenia identified several genes in the NMDA-PSD that were differentially affected by smoking in patients. The present findings suggest that smoking may differentially modulate glutamatergic function in schizophrenic patients and control subjects. The biological mechanisms underlying chronic tobacco use are likely to differ substantially between these two groups.
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Affiliation(s)
- S Mexal
- Department of Psychiatry, University of Colorado at Denver and Health Sciences Center, Aurora, CO 80045, USA
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Lipmanson RC, Davalos DB, Hood R, Freedman R, Ross RG. 92 EFFECTS OF PRENATAL EXPOSURE TO NICOTINE ON THE MISMATCH NEGATIVITY IN YOUNG INFANTS. J Investig Med 2005. [DOI: 10.2310/6650.2005.00005.91] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Lipmanson RC, Davalos DB, Hood R, Freedman R, Ross RG. 65 EFFECTS OF PRENATAL EXPOSURE TO NICOTINE ON THE MISMATCH NEGATIVITY IN YOUNG INFANTS. J Investig Med 2005. [DOI: 10.2310/6650.2005.00005.64] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Freedman R, Adams CE, Adler LE, Bickford PC, Gault J, Harris JG, Nagamoto HT, Olincy A, Ross RG, Stevens KE, Waldo M, Leonard S. Inhibitory neurophysiological deficit as a phenotype for genetic investigation of schizophrenia. Am J Med Genet 2003; 97:58-64. [PMID: 10813805 DOI: 10.1002/(sici)1096-8628(200021)97:1<58::aid-ajmg8>3.0.co;2-y] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Many investigators have proposed that biological endophenotypes might facilitate the genetic analysis of schizophrenia. A deficit in the inhibition of the P50 evoked response to repeated auditory stimuli has been characterized as a neurobiological deficit in schizophrenia. This deficit is linked to a candidate gene locus, the locus of the alpha7-nicotinic cholinergic receptor subunit gene on chromosome 15q14. Supportive evidence has been found by other investigators, including: 1) linkage of schizophrenia to the same locus; 2) linkage of bipolar disorder to the locus; and 3) replication of the existence of this neurobiological deficit and its relation to broader neuropsychological deficits in schizophrenia. It is certain that there are many genetic factors in schizophrenia and bipolar disorder; what is needed is a complete and precise description of the contribution of each individual factor to the pathophysiology of these illnesses.
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Affiliation(s)
- R Freedman
- Psychiatry and Pharmacology, University of Colorado, CO 80262, USA.
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Leonard S, Adler LE, Benhammou K, Berger R, Breese CR, Drebing C, Gault J, Lee MJ, Logel J, Olincy A, Ross RG, Stevens K, Sullivan B, Vianzon R, Virnich DE, Waldo M, Walton K, Freedman R. Smoking and mental illness. Pharmacol Biochem Behav 2001; 70:561-70. [PMID: 11796154 DOI: 10.1016/s0091-3057(01)00677-3] [Citation(s) in RCA: 195] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Patients with mental illness have a higher incidence of smoking than the general population and are the major consumers of tobacco products. This population includes subjects with schizophrenia, manic depression, depression, posttraumatic stress disorder (PTSD), attention-deficit disorder (ADD), and several other less common diseases. Smoking cessation treatment in this group of patients is difficult, often leading to profound depression. Several recent findings suggest that increased smoking in the mentally ill may have an underlying biological etiology. The mental illness schizophrenia has been most thoroughly studied in this regard. Nicotine administration normalizes several sensory-processing deficits seen in this disease. Animal models of sensory deficits have been used to identify specific nicotinic receptor subunits that are involved in these brain pathways, indicating that the alpha 7 nicotinic receptor subunit may play a role. Genetic linkage in schizophrenic families also supports a role for the alpha 7 subunit with linkage at the alpha 7 locus on chromosome 15. Bipolar disorder has some phenotypes in common with schizophrenia and also exhibits genetic linkage to the alpha 7 locus, suggesting that these two disorders may share a gene defect. The alpha 7 receptor is decreased in expression in schizophrenia. [(3)H]-Nicotine binding studies in postmortem brain indicate that high-affinity nicotinic receptors may also be affected in schizophrenia.
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Affiliation(s)
- S Leonard
- Department of Psychiatry, University of Colorado Health Sciences Center, Box C-268-71, 4200 East 9th Avenue, Denver, CO 80262, USA.
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Abstract
Many children of a schizophrenic parent may inherit a portion of the genetic risk factors for schizophrenia. The frequency of DSM-IV psychopathology in children of a schizophrenic parent and the frequency and type of mental health treatment accessed by these youths is not well understood. Twenty-eight adults with schizophrenia were identified and 43 of their 6--15 year old children recruited. Clinical diagnoses, based on a structured DSM-IV interview; severity of impairment, based on the Child Global Assessment Scale; and treatment histories were obtained. Seventy-four per cent of children-with-a-schizophrenic-parent met diagnostic criteria for a current Axis I psychiatric disorder. The most common diagnostic categories included attention deficit/hyperactivity disorder (40%), any anxiety disorder (23%), and any depressive disorder (12%). Psychosis was present in 9% of this childhood sample. Of those children with a psychiatric diagnosis, 47% demonstrated current moderate or severe impairment. Approximately half of the children had received mental health evaluations and 26% had experienced at least one psychiatric medication trial. Children-with-a-schizophrenic-parent have frequent, often impairing, psychiatric problems. Despite this high prevalence, mental health evaluation and treatment is of similar frequency and type to other at-risk populations. The effectiveness and appropriateness of standard treatments remain unstudied in children-with-a-schizophrenic-parent.
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Affiliation(s)
- R G Ross
- Denver Veterans Administration Medical Center, Research Services (151), 1055 Clermont Street, Denver, CO 80220, USA.
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Ross RG, Olincy A, Zerbe G, Radant A. Which duration of postsaccadic slowing identifies anticipatory saccades during smooth pursuit eye movements? Psychophysiology 2001; 38:325-33. [PMID: 11347877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
Increased frequency of anticipatory saccades during smooth pursuit eye movements is a potential marker of genetic risk for schizophrenia. Postsaccadic slowing criteria are used to separate anticipatory from other types of saccades. However, the necessary duration of slowed pursuit required to identify an anticipatory saccade remains undetermined. We explored the effect of various postsaccadic slowing duration criteria on effect size in a comparison of younger and older schizophrenic and normal adults. For large anticipatory saccades, varying the duration of postsaccadic slowing criteria did not notably change effect size. For smaller leading saccades, a limited 50-ms duration postsaccadic slowing criterion produced the largest effect size (1.54), and maintained a similar effect size across a broad age range. Leading saccades with a limited duration postsaccadic slowing criteria are a possible marker of genetic risk for schizophrenia.
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Affiliation(s)
- R G Ross
- Department of Psychiatry, University of Colorado Health Sciences Center, Denver, USA.
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Buervenich S, Carmine A, Arvidsson M, Xiang F, Zhang Z, Sydow O, Jönsson EG, Sedvall GC, Leonard S, Ross RG, Freedman R, Chowdari KV, Nimgaonkar VL, Perlmann T, Anvret M, Olson L. NURR1 mutations in cases of schizophrenia and manic-depressive disorder. Am J Med Genet 2000. [PMID: 11121187 DOI: 10.1002/1096-8628(20001204)96:] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Transgenic mice lacking the nuclear orphan transcription factor Nur-related receptor 1 (Nurr1) fail to develop mesencephalic dopamine neurons. There is a highly homologous NURR1 gene in humans (formerly known as NOT) which therefore constitutes a good candidate gene for neurologic and psychiatric disorders with an involvement of the dopamine neuron system, such as Parkinson's disease, schizophrenia, and manic-depression. By direct sequencing of genomic DNA, we found two different missense mutations in the third exon of NURR1 in two schizophrenic patients and another missense mutation in the same exon in an individual with manic-depressive disorder. All three mutations caused a similar reduction of in vitro transcriptional activity of NURR1 dimers of about 30-40%. Neither of these amino acid changes, nor any sequence changes whatsoever, were found in patients with Parkinson's disease or control DNA material of normal populations. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:808-813, 2000.
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Affiliation(s)
- S Buervenich
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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Buervenich S, Carmine A, Arvidsson M, Xiang F, Zhang Z, Sydow O, Jönsson EG, Sedvall GC, Leonard S, Ross RG, Freedman R, Chowdari KV, Nimgaonkar VL, Perlmann T, Anvret M, Olson L. NURR1 mutations in cases of schizophrenia and manic-depressive disorder. Am J Med Genet 2000. [PMID: 11121187 DOI: 10.1002/1096-8628(20001204)] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Transgenic mice lacking the nuclear orphan transcription factor Nur-related receptor 1 (Nurr1) fail to develop mesencephalic dopamine neurons. There is a highly homologous NURR1 gene in humans (formerly known as NOT) which therefore constitutes a good candidate gene for neurologic and psychiatric disorders with an involvement of the dopamine neuron system, such as Parkinson's disease, schizophrenia, and manic-depression. By direct sequencing of genomic DNA, we found two different missense mutations in the third exon of NURR1 in two schizophrenic patients and another missense mutation in the same exon in an individual with manic-depressive disorder. All three mutations caused a similar reduction of in vitro transcriptional activity of NURR1 dimers of about 30-40%. Neither of these amino acid changes, nor any sequence changes whatsoever, were found in patients with Parkinson's disease or control DNA material of normal populations. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:808-813, 2000.
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Affiliation(s)
- S Buervenich
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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Buervenich S, Carmine A, Arvidsson M, Xiang F, Zhang Z, Sydow O, Jönsson EG, Sedvall GC, Leonard S, Ross RG, Freedman R, Chowdari KV, Nimgaonkar VL, Perlmann T, Anvret M, Olson L. NURR1 mutations in cases of schizophrenia and manic-depressive disorder. Am J Med Genet 2000; 96:808-13. [PMID: 11121187 DOI: 10.1002/1096-8628(20001204)96:6<808::aid-ajmg23>3.0.co;2-e] [Citation(s) in RCA: 119] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Transgenic mice lacking the nuclear orphan transcription factor Nur-related receptor 1 (Nurr1) fail to develop mesencephalic dopamine neurons. There is a highly homologous NURR1 gene in humans (formerly known as NOT) which therefore constitutes a good candidate gene for neurologic and psychiatric disorders with an involvement of the dopamine neuron system, such as Parkinson's disease, schizophrenia, and manic-depression. By direct sequencing of genomic DNA, we found two different missense mutations in the third exon of NURR1 in two schizophrenic patients and another missense mutation in the same exon in an individual with manic-depressive disorder. All three mutations caused a similar reduction of in vitro transcriptional activity of NURR1 dimers of about 30-40%. Neither of these amino acid changes, nor any sequence changes whatsoever, were found in patients with Parkinson's disease or control DNA material of normal populations. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:808-813, 2000.
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Affiliation(s)
- S Buervenich
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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Abstract
PURPOSE To determine the prevalence of reversible airway obstruction in a group of professional football training camp participants. METHODS All attendees at a Canadian Football League team rookie preseason training camp were invited to participate in a protocol designed to elicit symptoms and signs of reversible airway obstruction (asthma) during the initial preparticipation examination. Those agreeing to the protocol completed a questionnaire containing standardized inquiries about a past history of asthma and the presence of symptoms. Participants then underwent spirometry testing to determine lung function before and after receiving a standardized dose of bronchodilator medication. Players showing evidence of airway obstruction during initial testing and still on the team roster underwent repeat spirometry testing and formal pulmonary function testing during the football season. The follow-up pulmonary function tests were performed to determine those that might benefit from treatment for asthma. RESULTS Nineteen of 34 (56%) players agreeing to participate had significant reversible airway obstruction as defined by a 12% or greater reversibility in forced expiratory volume in one second (FEV1), peak expiratory flow rate (PEFR), and/or forced expiratory flow rate between 25 and 75% of forced vital capacity (FEF 25-75). In most participants, the diagnosis was made on the basis of spirometry alone. Of those testing positive during initial inquiry, 88% remained positive on repeat spirometry, and 73% had reversible airway obstruction during more stringently controlled hospital-based pulmonary function testing. Those players treated for previously undiagnosed asthma noted an improvement in subjective athletic performance during the football season. CONCLUSION Based on the remarkably high prevalence of undiagnosed asthma in this group, it may prove worthwhile to test elite football players using lung function parameters.
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Affiliation(s)
- R G Ross
- Oregon Health Sciences University, Department of Family Medicine, Klamath Falls 97601, USA.
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Ross RG, Olincy A, Harris JG, Sullivan B, Radant A. Smooth pursuit eye movements in schizophrenia and attentional dysfunction: adults with schizophrenia, ADHD, and a normal comparison group. Biol Psychiatry 2000; 48:197-203. [PMID: 10924662 DOI: 10.1016/s0006-3223(00)00825-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND Smooth pursuit eye movement (SPEM) abnormalities are found in schizophrenia. These deficits often are explained in the context of the attentional and inhibitory deficits central to schizophrenia psychopathology. It remains unclear, however, whether these attention-associated eye movement abnormalities are specific to schizophrenia or are a nonspecific expression of attentional deficits found in many psychiatric disorders. Adult attention-deficit/hyperactivity disorder (ADHD) is an alternative disorder with chronic attentional and inhibitory dysfunction. Thus, a comparison of SPEM in adult schizophrenia and adult ADHD will help assess the specificity question. METHODS SPEM is recorded during a 16.7 degrees per second constant velocity task in 17 adults with ADHD, 49 adults with schizophrenia, and 37 normal adults; all groups included individuals between ages 25-50 years. RESULTS Smooth pursuit gain and the frequency of anticipatory and leading saccades are worse in schizophrenic subjects, with normal and ADHD subjects showing no differences on these variables. CONCLUSIONS Many attention-associated SPEM abnormalities are not present in most subjects with ADHD, supporting the specificity of these findings to the attentional deficits seen in schizophrenia.
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Affiliation(s)
- R G Ross
- Department of Psychiatry of the Denver Veterans Administration Medical Center, Denver, CO, USA
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Ross RG, Harris JG, Olincy A, Radant A. Eye movement task measures inhibition and spatial working memory in adults with schizophrenia, ADHD, and a normal comparison group. Psychiatry Res 2000; 95:35-42. [PMID: 10904121 DOI: 10.1016/s0165-1781(00)00153-0] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Schizophrenia and attention deficit/hyperactivity disorder (ADHD) are both associated with deficits in inhibition and working memory, although in ADHD the working memory deficit is hypothesized to be secondary to the inhibitory deficit. This similarity in cognitive processes has been paralleled by similarities across the two groups in the performance of working memory and inhibition tasks. The delayed oculomotor response task is an alternative task, which may allow greater separation of working memory from inhibitory components, and thus its use may provide additional information on primary vs. secondary deficits in these disorders. Ten young adult ADHD sufferers, 10 schizophrenic subjects, and 10 normal subjects were matched on age, gender, and education. Eye movements were recorded during delayed oculomotor response tasks with 1- and 3-s delays. Both the ADHD and the schizophrenic subjects demonstrated dis-inhibition (an increased percentage of premature saccades); however only schizophrenic subjects demonstrated an impaired working memory (decreased spatial accuracy of the remembered saccade). The results are consistent with the hypothesis that working memory is a primary deficit in schizophrenia, but secondary to the inhibitory deficit in ADHD.
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Affiliation(s)
- R G Ross
- Psychiatry Service, Denver Veterans Administration Medical Center, Denver, CO 80220, USA.
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Olincy A, Ross RG, Harris JG, Young DA, McAndrews MA, Cawthra E, McRae KA, Sullivan B, Adler LE, Freedman R. The P50 auditory event-evoked potential in adult attention-deficit disorder: comparison with schizophrenia. Biol Psychiatry 2000; 47:969-77. [PMID: 10838065 DOI: 10.1016/s0006-3223(00)00239-0] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Attention-deficit/hyperactivity disorder (ADHD) and schizophrenia are both conceptualized as disorders of attention. Failure to inhibit the P50 auditory event-evoked response, extensively studied in schizophrenia, could also occur in ADHD patients, if these two illnesses have common underlying neurobiological substrates. METHODS This study examined the inhibition of the P50 auditory event-evoked potential in 16 unmedicated adults with ADHD, 16 schizophrenic outpatients, and 16 normal control subjects. Auditory stimuli were presented in a paired stimulus, conditioning-testing paradigm. RESULTS The amplitude of initial or conditioning P50 response did not differ between the three groups; however, significant effects of psychiatric diagnosis on the amplitude of the test response and the ratio of the test to the conditioning response amplitudes were observed. Schizophrenic patients' P50 ratios and test amplitudes were higher than both the ADHD and normal groups. CONCLUSIONS Adults with ADHD do not have the inhibitory deficit seen in patients with schizophrenia, suggesting that the mechanism of attentional disturbance in the two illnesses may be fundamentally different.
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Affiliation(s)
- A Olincy
- Department of Psychiatry, University of Colorado Health Sciences Center, Denver 80262, USA
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Abstract
Schizophrenia is a complex illness with multiple pathophysiologic factors that contribute to its psychopathology. One strategy to identify these factors is to observe them in isolation from each other, by characterizing their expression in the relatives of schizophrenic probands. By Mendel's second law, each genetic factor should be independently distributed in a sibship, so that each can be observed by itself, uncomplicated by the general problems of the illness. Such independently distributed phenotypes are obviously useful for genetic analyses; however, they can also be considered together, to model how various brain dysfunctions may combine to produce psychoses. In addition to a sensory gating deficit linked to the alpha 7-nicotinic acetylcholine receptor locus, schizophrenics and their families have a number of other deficits, including decreased hippocampal volume on magnetic resonance images and increased plasma levels of the dopamine metabolite homovanillic acid. Although such research is far from complete, a heuristic model combining a sensory gating deficit, decreased hippocampal neuron capacity, and increased dopaminergic neurotransmission is consonant with current understanding of the neuropsychology of schizophrenia.
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Affiliation(s)
- M C Waldo
- Department of Psychiatry, University of Colorado Health Sciences Center, Denver 80262, USA
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Ross RG, Olincy A, Harris JG, Radant A, Adler LE, Compagnon N, Freedman R. The effects of age on a smooth pursuit tracking task in adults with schizophrenia and normal subjects. Biol Psychiatry 1999; 46:383-91. [PMID: 10435204 DOI: 10.1016/s0006-3223(98)00369-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
BACKGROUND Performance during a smooth pursuit eye movement (SPEM) task has been proposed as a marker of genetic risk for schizophrenia, although the precise component of SPEM tracking most associated with genetic risk remains undetermined. Normal adult aging is associated with deterioration on SPEM tasks; it remains unclear whether investigations of SPEM abnormalities will allow inclusion of older subjects in genetic studies. This study examines 1) the effect of normal aging on several components of SPEM performance; and 2) whether schizophrenic-normal differences found in young adults continue over a broad adult age span. METHODS SPEM was recorded during a 16.7 degrees per sec constant velocity task in 64 normal adults, ages 18 to 79 years, and 58 schizophrenic subjects, ages 18 to 70 years. RESULTS Smooth pursuit gain, the percent of total eye movements due to catch-up saccades, the frequency of large anticipatory saccades, and the frequency of leading saccades all deteriorate with increasing age. After correction for age, schizophrenic to control differences persist on most eye movement variables with the largest effect sizes for leading saccades (1.56) and smooth pursuit gain (1.17). CONCLUSIONS The tendency to use saccades to anticipate target motion, even in small steps (leading saccades), deserves further attention as a potential marker useful in genetic analyses.
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Affiliation(s)
- R G Ross
- Department of Psychiatry, University of Colorado Health Sciences Center, Denver, USA
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Ross RG, Olincy A, Radant A. Amplitude criteria and anticipatory saccades during smooth pursuit eye movements in schizophrenia. Psychophysiology 1999; 36:464-8. [PMID: 10432795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Increased frequency of anticipatory saccades during smooth pursuit eye movements is a potential marker of genetic risk for schizophrenia even in the absence of clinical symptomology. The operational definition of anticipatory saccades has often included an amplitude criterion; however, these amplitude criteria have often differed across studies. This study reports on the effect of varying amplitude criteria on the effect size in a comparison of 29 schizophrenic adults and 29 normal subjects during a 16.7 degrees/s constant velocity task. The inclusion of small amplitude anticipatory saccades, with amplitudes of 1-4 degrees, consistently increased effect size (largest effect size = 1.61). The inclusion of large anticipatory saccades, with amplitudes of 4 degrees or greater, had an inconsistent impact on effect size. The separation of anticipatory saccades into leading saccades (anticipatory saccades with amplitude 1-4 degrees) and large anticipatory saccades (amplitude > 4 degrees) deserves further exploration.
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Affiliation(s)
- R G Ross
- Department of Psychiatry, University of Colorado Health Sciences Center, Denver, USA.
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Abstract
This review describes the strategy of using elementary phenotypes for neurobiological and genetic linkage studies of schizophrenia. The review concentrates on practical aspects of selecting the phenotype and then understanding the confounds in its measurement and interpretation. Examples from the authors' studies of deficits in P50 inhibition and smooth pursuit eye movement dysfunction are presented. These two phenotypes share considerable similarity in their neurobiology, including a similar response to nicotine. They also appear to co-segregate with the genetic risk for schizophrenia as autosomal co-dominant phenotypes. Although most schizophrenic patients inherit these abnormalities unilinealy, i.e., from one parent, apparent bilineal inheritance produces a more severe illness, observed clinically as childhood-onset schizophrenia. The initial study showing linkage of the P50 deficit to the chromosome 15q14 locus of the alpha 7-nicotinic acetylcholine receptor is an example of the potential usefulness of these phenotypes for combined genetic and neurobiological study of schizophrenia.
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Affiliation(s)
- L E Adler
- Department of Psychiatry, University of Colorado Health Sciences Center, Denver 80262, USA
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Ross RG, Olincy A, Harris JG, Radant A, Hawkins M, Adler LE, Freedman R. Evidence for bilineal inheritance of physiological indicators of risk in childhood-onset schizophrenia. Am J Med Genet 1999; 88:188-99. [PMID: 10206241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Childhood-onset schizophrenia is proposed to be associated with increased genetic loading compared with adult-onset schizophrenia because of its earlier age of onset and generally greater severity of symptoms. Diminished suppression of P50 auditory evoked responses to repeated stimuli and elevated anticipatory saccades during smooth pursuit eye movements are markers of genetic risk that are found in members of families with schizophrenia even in the absence of the full clinical disorder and appear to be transmitted in a single gene autosomal dominant fashion. Adult-onset schizophrenia is generally associated with one parent who demonstrates abnormal P50 sensory gating and elevated anticipatory saccades and one parent who is normal on the physiologic measures (i.e., unilineal inheritance). This study investigates whether childhood-onset schizophrenia is similarly unilineal or is associated with the inheritance of genetic risk factors from both parents (i.e., bilineal inheritance). Ten childhood-onset schizophrenic probands and their parents were studied. Their P50 sensory gating and anticipatory saccades were compared with adult-onset schizophrenic probands and their parents. Bilineality, measured as physiological impairment in both parents, occurred more frequently in childhood-onset probands than in adult-onset probands for both P50 sensory gating deficits (60% versus 13%) and elevated anticipatory saccades (60 versus 0%). Additionally, childhood-onset schizophrenic probands performed more poorly than adult-onset probands on the anticipatory saccade measure. This physiological evidence suggests that childhood-onset schizophrenia may be associated with increased genetic loading because of contributions of genetic risk from both parents.
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Affiliation(s)
- R G Ross
- Department of Psychiatry, University of Colorado Health Sciences Center, Denver Veterans Administration Medical Center, USA.
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33
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Abstract
Schizophrenia has long been associated with difficulties in visual tracking of a moving object. Deficits are most notable in tracking tasks that require inhibition of saccades during active smooth pursuit. In order to assess whether there is a more global problem in inhibition of other eye movement systems while the smooth pursuit system is active, this study examined cancellation of the vestibular ocular reflex (VOR). Cancellation of the VOR occurs in a task in which the subject is rotated while looking at a target that is also being rotated. This requires the subject to use the pursuit system to override the VOR, maintain the eye at a stable location within the orbit, and thus retain visual gaze upon the target. Thirteen individuals with schizophrenia and 15 normals were assessed during clockwise rotation at 60 degrees s-1. Schizophrenic subjects had a significant increase in counterclockwise slow velocity eye movements, suggesting an impaired ability to cancel the VOR. Cancellation of the VOR is thus another example of a breakthrough of an alternative eye movement system while the smooth pursuit system is active. Because of the simplicity of the VOR and its suitability for animal modeling, investigation of this phenomenon may delineate more precisely the mechanisms of visual tracking dysfunction in schizophrenia.
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Affiliation(s)
- S Warren
- University of Colorado Health Sciences Center, Dept of Psychiatry, Denver 80262, USA
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34
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Abstract
BACKGROUND Smooth pursuit eye movement (SPEM) abnormalities are a putative marker of genetic risk for schizophrenia. Accurate SPEM performance requires the subject to activate neural systems responsible for smooth pursuit tracking, while simultaneously suppressing activity of neurons responsible for saccadic movements that would move the eye ahead of the target. This study examined whether specific aspects of SPEM dysfunction cosegregate with genetic risk in parents of schizophrenic probands. METHODS Eighteen probands and their parents had SPEM recorded. Parents with an ancestral history of schizophrenia were hypothesized to be more likely than their spouses without such a history to carry a genetic risk for schizophrenia. RESULTS Ten families had a single parent with a positive ancestral history for schizophrenia. The frequency of anticipatory saccades, which were mostly small, and the fraction of total eye movement that they represented were the only measures that differentiated the more likely genetic carrier parents in these families from their spouses and age-matched normals. CONCLUSIONS Failure to suppress saccadic anticipation of target motion during smooth pursuit appears an aspect of SPEM dysfunction related to presumed genetic risk for schizophrenia.
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Affiliation(s)
- R G Ross
- University of Colorado Health Sciences Center, Denver 80262, USA
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35
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Abstract
Restoration of a patient's full range of motion, strength, and function are the primary goals of occupational and physical therapy. Immobilization of normal connective tissue leads to biochemical, biomechanical, and physiologic changes within a week. These changes are magnified in the presence of trauma or edema, and they may create permanent damage if not addressed swiftly and properly. This is best accomplished by applying specific types of stress to the involved and associated structures at optimal intervals during the rehabilitation process. Load must be applied at adequate intensity and duration to successfully affect the viscous property of connective tissue. This is necessary to effect permanent elongation of the restricted tissues. Early controlled motion is vital to prevent the negative changes associated with immobilization and to maintain normal viscoelasticity and homeostasis of connective tissue. Hand therapists must have a thorough understanding of the changes associated with injured structures. Only then can they provide optimal stress delivery to facilitate restoration of function.
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Affiliation(s)
- L M Cyr
- Physical Therapy Center Torrington, CT 06790, USA
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Abstract
This study examined whether schizophrenics' cigarette smoking normalized smooth pursuit eye movement abnormalities. Fifteen schizophrenic and 15 nonschizophrenic subjects abstained from their usual cigarette smoking for an average of 10 h. Their baseline performance during a constant velocity smooth pursuit task was then assessed. The subjects smoked as much as they desired in a 10-min period and then were retested immediately postsmoking, and 10 and 20 min later. Smooth pursuit gain and the percentage of total eye movement due to various saccadic subtypes were computed using infrared oculography and computerized pattern recognition software. After smoking, smooth pursuit gain increased and the percentage of total eye movements due to leading saccades decreased significantly in the schizophrenic patients. There were no changes in the gain or leading saccades of nonschizophrenic subjects after smoking. Nicotinic receptor dysfunction may be a candidate mechanism for smooth pursuit eye movement abnormalities in schizophrenia.
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Affiliation(s)
- A Olincy
- Department of Psychiatry, Denver Veterans Administration Medical Center, CO, USA
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Abstract
Difficulties with inhibiting inappropriate responses, i.e. disinhibition, and problems with spatial memory are both presumed to be a part of the phenotypic expression of the genetic risk for schizophrenia. Schizophrenic probands are impaired on saccadic eye movement tasks which require (a) response inhibition to prepotent stimuli and (b) generation of an accurate response to a remembered or calculated spatial location, but it is unknown how these deficits are inherited. Sixteen schizophrenic probands, their 32 parents, and two normal control groups completed a delayed oculomotor response and an antisaccade task. The parents with a positive ancestral family history for chronic psychosis (n = 8) were presumed to be more likely than their family history-negative spouses to be genetic carriers for schizophrenia. Probands and their positive family history parents had more failures of response inhibition than did normal control groups. However, it was the probands and their negative family history spouses who demonstrated impaired accuracy of the remembered- or antisaccades. Disinhibition may be closely tied to a specific genetic risk for schizophrenia. However, a second familial factor related to the maintenance or manipulation of spatial information may also contribute to the genetic risk of the full clinical disorder.
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Affiliation(s)
- R G Ross
- University of Colorado Health Sciences Center, Department of Psychiatry, Denver 80262, USA.
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38
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Abstract
Tthe antisaccade eye movement task, which has been linked to frontal lobe function, presents a target in one visual field and asks subjects to move their eyes to the same location in the opposite field. The task requires inhibition of the reflexive prosaccade to the cue, initiation of the antisaccade to the opposite field, and visuo-spatial memory of the cue location. Forty-two subjects from 19-79 years of age performed this task and a control task, visually guided saccades to the cue itself, to determine which functions are affected by aging. The time to initiate antisaccades increased linearly with age at a rate greater than the time to initiate visually guided saccades. This difference suggests that the processing time to inhibit the incorrect movement to the cue is selectively increased with age. Older subjects also made more incorrect prosaccadic movements to the cue, a finding consistent with the loss of inhibitory processing capacity. The accuracy of movements did not change, which suggests that visuo-spatial memory is unaffected by aging.
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Affiliation(s)
- A Olincy
- Department of Psychiatry, Denver Veterans Administration Medical Center, and University of Colorado Health Sciences Center, 80262, USA
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39
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Abstract
OBJECTIVE Disordered smooth-pursuit eye movements (SPEM) and, specifically, small anticipatory saccades that disrupt SPEM have been hypothesized to be a marker of genetic vulnerability to schizophrenia. This study compares SPEM in children of schizophrenic parents with normally developing control children to assess whether SPEM abnormalities are also present in a subset of at-risk children. METHOD With infrared oculography, SPEM was examined in 13 children of schizophrenic parents and 19 normally developing controls (aged 6 to 15 years). Measures of smooth-pursuit gain and root mean square error were used in addition to more specific measures of catch-up saccades and anticipatory saccades. RESULTS Children of schizophrenic parents differed from normally developing controls on gain and root mean square error, but not on catch-up saccades. Small anticipatory saccades were significantly more frequent in the at-risk group. The percentage of total eye movements due to anticipatory saccades identified 54% of the at-risk group (compared with none of the control group) as performing more than two standard deviations above (worse than) the control mean. CONCLUSIONS The presence of increased anticipatory saccades is evidence for an oculomotor dysfunction that may be a phenotype of the genetic risk for schizophrenia, expressed years prior to the possible development of clinical illness.
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Affiliation(s)
- R G Ross
- University of Colorado Health Sciences Center, Denver, USA.
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Ross RG, Radant AD, Young DA, Hommer DW. Saccadic eye movements in normal children from 8 to 15 years of age: a developmental study of visuospatial attention. J Autism Dev Disord 1994; 24:413-31. [PMID: 7961328 DOI: 10.1007/bf02172126] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
This cross-sectional study used saccadic eye movements, as measured by infrared occulography, to assess several aspects of visuospatial attention in normal children ages 8-15 years. Saccadic latency (a global measure of the ability to shift visuospatial attention), the ability to suppress extraneous saccades during fixation, and the ability to inhibit task-provoked anticipatory saccades all improve with age. However, the pattern of development differs for different tasks; saccadic latency shortens at a linear rate across the age range 8-15 years, while the capacity to inhibit anticipatory saccades matures by 12-13 years of age, and the ability to suppress saccades matures by 10 years of age. Analyses of age-related changes in oculomotor measures of attention may provide a novel approach in the study of children with attentional difficulties.
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Affiliation(s)
- R G Ross
- Department of Psychiatry and Behavioral Sciences, University of Washington
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Abstract
OBJECTIVE Attention-deficit hyperactivity disorder (ADHD) has been postulated to be related to dysfunction of the prefrontal cortex. In the oculomotor delayed response task, a subject is cued as to where he or she should look (shift visual gaze to) but must delay a short period and then shift gaze to the location where the cue previously existed but no longer exists (a memory-guided saccade). Dependent measures from this task provide information on three functions tentatively tied to prefrontal cortex functioning: the ability to inhibit response (during the delay period), preparation of motor response (inversely tied to the latency of shifting visual gaze), and accuracy of working visuospatial memory (accuracy of the memory-guided saccade). METHOD Thirteen children with ADHD and 10 normal controls, aged 9 to 12 years, were tested using an 800-msec delay period. RESULTS Children with ADHD showed, relative to normal controls, deficits on inhibiting response during the delay period but no differences in latency (preparation of motor response) or accuracy of visuospatial memory. CONCLUSIONS These results support the hypothesis that the primary deficit in ADHD is difficulty in inhibition of response. This deficit may be associated with pathology located outside the dorsolateral prefrontal cortex.
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Abstract
OBJECTIVE To examine age-related changes in smooth pursuit tracking. METHOD Using infrared occulography, smooth pursuit eye movements are examined in 53 normal 7- to 15-year-old children during 6 degrees and 12 degrees/second visual pursuit. In addition to smooth pursuit gain and saccadic frequency, measures of mean amplitude per second are introduced to facilitate comparison across age and target speed. RESULTS The 6 degrees/second task is found to be easier than the 12 degrees/second task. Age is correlated with smooth pursuit system performance but not saccadic system performance during 12 degrees/second pursuit. No measure correlates with age during 6 degrees/second pursuit. CONCLUSIONS Eye movements improve as children age. The future use of smooth pursuit eye movements to study children and adolescents with and at risk for schizophrenia must control for developmental changes.
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Affiliation(s)
- R G Ross
- Department of Psychiatry, University of Washington, Seattle
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43
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Affiliation(s)
- R G Ross
- Department of Psychiatry, University of Washington, Seattle 98195
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44
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Ross RG. Educational Strategies to Improve Preventive Care: Improving the performance of periodic health examinations. Can Fam Physician 1992; 38:341-345. [PMID: 21221260 PMCID: PMC2145424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Performance of the periodic health examination and related preventive maneuvers has been shown to be suboptimal by both residents and faculty. Research into methods of improving performance of the periodic health examination shows that a number of methods are available to remedy the lack of effective delivery of prevention by health professionals. An educational prescription based on a literature review is outlined. Specific educational objectives are discussed.
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Davidson DW, Ross RG. Book reviews. J INCL PHENOM MACRO 1985. [DOI: 10.1007/bf00658867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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48
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Abstract
Nitrates, urea, and amino acids were suitable sources of nitrogen, within a narrow range of concentrations, for perithecial development of Venturia inaequalis in a synthetic medium. Ammonium sulfate was not. The concentration of amino acid nitrogen required to inhibit the formation of perithecia varied with the amino acid. Zinc appeared to stimulate perithecial production. Amino acids differed in the nitrogen concentrations required to inhibit formation of perithecia. Perithecia developed in low concentrations of arabinose, glucose, sucrose, lactose, and maltose but did not develop in xylose, ribose, fructose, mannose, or galactose. The disaccharides were particularly suitable. Thiamine appeared to be necessary for ascospore formation.
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49
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Abstract
Perithecia of Venturia inaequalis were produced in vitro on apple leaf discs which had been sterilized in propylene oxide and then placed on water agar, potato-dextrose agar, or potato-dextrose agar supplemented with apple leaf decoction. The discs were inoculated with a drop of a conidial suspension of two sexually compatible strains of V. inaequalis, incubated at room temperature for 2 weeks, and then grown at 8 °C for 4 to 5 months.Perithecia were also produced on sterile leaf discs placed on perlite, vermiculite, sand, filter paper, or glass rings in screw-cap vials with distilled water added to supply moisture. Using perlite, perithecia were developed on discs of green and fallen apple leaves collected from the orchard at intervals during the summer and fall and on leaves at different stages of development from trees growing in the greenhouse. Few perithecia developed on newly unfolded leaves from the latter unless the leaves were leached before inoculation. Perithecia developed on sterile discs from green apple leaves of varieties with varying degrees of susceptibility to V. inaequalis and on green leaf discs of the pear variety Kieffer. Perithecia production was most abundant at 4 °C and no perithecia were produced at or above 15 °C.
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50
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Ross RG. THE EFFECT OF CERTAIN ELEMENTS, WITH EMPHASIS ON NITROGEN, ON THE PRODUCTION OF PERITHECIA OF VENTURIA INAEQUALIS (CKE.) WINT. ACTA ACUST UNITED AC 1961. [DOI: 10.1139/b61-061] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Various elements were tested for their effect on the formation of perithecia of Venturia inaequalis. Apart from nitrogen the elements tested had little effect on the formation of perithecia except at relatively high concentrations. Perithecia did not form in media containing low concentrations of nitrogen and this was influenced by the source of nitrogen and by the cation present in nitrate salts. Perithecial initials developed in higher nitrogen concentrations than perithecia. Nitrogen added 9 weeks after mating of two lines of the fungus prevented the formation of perithecia.Results were difficult to reproduce in a potato-dextrose apple leaf decoction medium but reproducible results were obtained in a synthetic medium.
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