Ionotropic glutamate receptor binding and subunit mRNA expression in thalamic nuclei in schizophrenia

OBJECTIVE

Both thalamic and glutamatergic dysfunction have been implicated in the pathophysiology of schizophrenia. The authors examined ionotropic glutamate receptor expression in postmortem samples from patients with schizophrenia and comparison subjects, using the hypothesis that glutamate receptor expression differs in limbic nuclei of the thalamus in schizophrenia.

METHOD

N-Methyl-D-aspartate (NMDA), AMPA, and kainate receptor expression was determined in six thalamic nuclei from 12 subjects with DSM-III-R diagnoses of schizophrenia and eight psychiatrically normal individuals. The authors used in situ hybridization to determine NMDAR1, NMDAR2A-NMDAR2D, gluR1-gluR7, KA1, and KA2 subunit mRNA levels and receptor autoradiography to determine binding to glutamate binding sites of the three receptor subtypes and to the glycine, polyamine, and ion channel binding sites of the NMDA receptor.

RESULTS

Glutamate receptor expression was lower at both transcriptional (NMDAR1, NMDAR2B, NMDAR2C, gluR1, gluR3, and KA2 subunit mRNAs) and posttranscriptional ([(3)H]ifenprodil and [(3)H]MDL105,519 binding to polyamine and glycine sites of the NMDA receptor) levels in the thalamus in patients with schizophrenia than in comparison subjects, but differences were most prominent in nuclei with reciprocal projections to limbic regions.

CONCLUSIONS

Abnormalities in NMDA, AMPA, and kainate receptor expression in limbic thalamus are suggestive of the NMDA receptor hypoactivity hypothesis of schizophrenia and are consistent with diminished glutamatergic activity in the thalamus in schizophrenia. Alternatively, these results could suggest abnormal glutamatergic innervation in afferent and/or efferent regions, which are limbic structures that have been implicated in this illness. These results may provide a neurochemical anatomical substrate for antipsychotic therapies targeting ionotropic glutamate receptors.

Relationship of cognitive functioning, adaptive life skills, and negative symptom severity in poor-outcome geriatric schizophrenia patients

The authors assessed whether cognitive functioning and negative symptoms are related to functional outcome across severity of negative symptoms and examined relationships between symptom domains in patients with high versus low negative symptom severity. The interrelationships between cognitive functioning and functional skills in poor-outcome geriatric schizophrenic patients were compared between those who were in the first (n = 81) and the fourth quartiles (n = 127) of negative symptom severity based on the normative data in the Positive and Negative Syndrome Scale. It was found that negative symptoms and cognitive functioning were the strongest correlates of functional status in geriatric poor-outcome schizophrenic patients--regardless of negative symptom severity. Interestingly, the greater the severity of negative symptoms, the less strongly negative symptoms were related to functional outcome. The present findings demonstrate that the relationship of cognitive functioning to social and adaptive functioning remains significant despite differing levels of negative symptom severity.

Contribution of Lewy body inclusions to dementia in patients with and without Alzheimer disease neuropathological conditions

CONTEXT

Lewy bodies (LBs) are intraneuronal inclusions in the brain that have been increasingly recognized as neuropathological lesions with relevance not only to Parkinson disease but also to Alzheimer disease. However, the degree to which the density of LBs in the brain contributes to the severity of dementia has not been clear.

OBJECTIVE

To determine the degree to which LB "burden" contributes to dementia.

DESIGN

Brain specimens were examined from 273 consecutive autopsies of elderly subjects residing in a nursing home. The numbers and densities of LBs were determined in multiple brain regions, and their correlation with a measure of cognition and functional status (Clinical Dementia Rating) during the 6 months preceding death was determined.

SETTING AND PATIENTS

Postmortem study of nursing home residents.

RESULTS

The severity of dementia correlated significantly and positively with the density of LBs. These correlations were independent of other neuropathological disorders commonly associated with dementia, including Alzheimer disease. The density of LBs correlated significantly with dementia severity whether or not the diagnostic criteria for Alzheimer disease were met and after the contribution of classical Alzheimer disease lesions, neuritic plaques, and neurofibrillary tangles had been accounted for by partial correlation analysis.

CONCLUSION

Lewy body inclusions appear to contribute significantly to cognitive deficits in the elderly in a manner that is independent of other neuropathological disorders. Arch Neurol. 2000;57:1145-1150

Mechanisms of killing of spores of Bacillus subtilis by iodine, glutaraldehyde and nitrous acid

Treatment of wild-type spores of Bacillus subtilis with glutaraldehyde or an iodine-based disinfectant (Betadine) did not cause detectable mutagenesis, and spores (termed alpha-beta-) lacking the major DNA-protective alpha/beta-type, small, acid-soluble proteins (SASP) exhibited similar sensitivity to these agents. A recA mutation did not sensitize wild-type or alpha-beta- spores to Betadine or glutaraldehyde, nor did spore treatment with these agents result in significant expression of a recA-lacZ fusion when the treated spores germinated. Spore glutaraldehyde sensitivity was increased dramatically by removal of much spore coat protein, but this treatment had no effect on Betadine sensitivity. In contrast, nitrous acid treatment of wild-type and alpha-beta- spores caused significant mutagenesis, with alpha-beta- spores being much more sensitive to this agent. A recA mutation further sensitized both wild-type and alpha-beta- spores to nitrous acid, and there was significant expression of a recA-lacZ fusion when nitrous acid-treated spores germinated. These results indicate that: (a) nitrous acid kills B. subtilis spores at least in part by DNA damage, and alpha/beta-type SASP protect against this DNA damage; (b) killing of spores by glutaraldehyde or Betadine is not due to DNA damage; and (c) the spore coat protects spores against killing by glutaraldehyde but not Betadine. Further analysis also demonstrated that spores treated with nitrous acid still germinated normally, while those treated with glutaraldehyde or Betadine did not.

Levels of mRNAs encoding synaptic vesicle and synaptic plasma membrane proteins in the temporal cortex of elderly schizophrenic patients

BACKGROUND

Electron microscopy and biochemical studies indicate that developmental abnormalities in synaptic organization may be present in brains of schizophrenic patients. This study determined whether these synaptic abnormalities are reflected in differential or uniform alterations in the expression of various synaptic protein genes in the left superior temporal gyrus of schizophrenic patients.

METHODS

Levels of mRNAs encoding four synaptic vesicle proteins (synaptotagmin I [p65], rab3a, synaptobrevin 1, and synaptobrevin 2) and two synaptic plasma membrane proteins (syntaxin 1A and SNAP-25) were measured postmortem in the left superior temporal gyrus from elderly (58-95 years) schizophrenic patients (n = 14) and age-matched control subjects (n = 9).

RESULTS

There were significant negative correlations between age and levels of synaptotagmin I (p65), rab3a, synaptobrevin 1, SNAP-25, and syntaxin 1A mRNAs in schizophrenic patients (-.692 < r < -.517,.003 < p <.030) but not in control subjects. Levels of all six synaptic mRNAs studied were increased in the younger (58-79 years) subgroup of schizophrenic patients compared to control subjects and older (80-95 years) subgroup of schizophrenic patients.

CONCLUSIONS

That similar abnormalities were found for mRNAs encoding different synaptic vesicle and synaptic plasma membrane proteins suggests that they reflect overall neurodevelopmental abnormalities in synaptic connectivity in the temporal cortex of schizophrenic patients rather than changes in the number of synaptic vesicles per synapse or abnormalities in a specific synaptic function.

The Caregiver Activity Survey (CAS): longitudinal validation of an instrument that measures time spent caregiving for individuals with Alzheimer's disease

Family members incur substantial financial costs during the course of caring for an individual with Alzheimer's disease. Much of this cost is associated with time spent in caregiving tasks, including supervision and communication with the patient, and assisting with activities of daily living. We have previously reported on the cross sectional reliability and validity of a scale that measures time spent caregiving, the Caregiver Activity Survey (CAS). This study extends our results to a longitudinal study of the validity of the instrument. Forty-four outpatients with Alzheimer's disease who lived with a primary caregiver were followed over a period of 1 year 6 months. At six month intervals, the patients were administered the Mini Mental State Exam (MMSE), Alzheimer's Disease Assessment Scale (ADAS), and the Physical Self Maintenance Scale (PSMS). Caregivers completed the CAS. Over time, the CAS correlated significantly with the MMSE (r=-0.58, p=0.000), ADAS cognitive subscale (r=0.56, p=0. 000) and PSMS (r=0.49, p=0.000). As patients declined, caregivers spent less time communicating with and more time supervising the patient. Excluding the communication item, time spent caregiving increased significantly over time. This prospective study longitudinally validates the CAS with Alzheimer's patients.

Effects of myocardial edema on the development of myocardial interstitial fibrosis

OBJECTIVE

The mechanism by which chronic myocardial edema causes cardiac dysfunction is poorly understood. We hypothesized that myocardial edema triggers cardiac fibrosis development resulting in cardiac dysfunction. Since collagen is the most abundant constituent of the interstitial matrix, we examined the effects of edema development on cardiac collagen metabolism.

METHODS

We utilized a chronic pulmonary artery banded rat model that produces right ventricular hypertrophy with myocardial edema and left ventricular edema without hypertrophy or hyperplasia. Wet to dry ratios (index of edema), collagen type I and III concentrations, prolyl 4-hydroxylase (P4-H) and collagen type I and III mRNA levels, collagenase activity and transforming growth factor-beta were measured in both ventricles.

RESULTS

Right and left ventricular wet to dry ratios were significantly elevated from 1 to 28 days after pulmonary artery banding compared to sham rats. Right and left ventricular collagen types I and III and P4-H mRNA levels increased significantly at 3 days followed by significant increases in right and left ventricular collagen concentration 7 days after pulmonary artery banding. Right ventricular collagenase activity increased at 3 days while left ventricular collagenase activity decreased 7 days after PA banding.

CONCLUSIONS

We conclude that myocardial edema preceded the observed increase in collagen deposition and that edema may have triggered increased collagen synthesis by fibroblasts. leading to fibrosis development.

Has familial aggregation in Alzheimer's disease been overestimated?

Studies of the familial aggregation of Alzheimer's disease have primarily used samples ascertained from tertiary care clinics which may not be representative of many AD patients, for example those residing at geriatric nursing homes. Survival analysis was used to investigate whether estimates of familial aggregation of AD based on a clinic-based AD proband (C-AD) sample (probands: N=544; first degree relatives; N=4267) differ from one ascertained at a nursing home (NH-AD; probands: N=225; first degree relatives; N=1772). The cumulative survival from AD was significantly worse in relatives of the C-AD probands and the overall relative risk (RR) of AD in this group was greater than twice that of relatives of the NH-AD probands. However, age at onset in C-AD probands was significantly earlier than in the NH-AD group and in both groups this factor was negatively associated with familial aggregation. When, for this reason, the proband samples were matched one-to-one by age at onset, dropping those probands with no match, the two curves were close to identical and the RR for the C-AD group of relatives was 1.0 The results suggest that estimates of familial risk of AD based on C-AD samples are not applicable and overestimate the extent of increased risk for relatives of more prevalent, later onset AD probands. However, the overestimate can be explained by the typically earlier age at onset in C-AD samples as opposed to a sampling bias related to the proband's family history status per se. The relationship between onset age and familial aggregation suggests that no single estimate of the age-dependent risk (survival curve) is uniformly appropriate for relatives of AD probands.

Differential preservation of cognitive functions in geriatric patients with lifelong chronic schizophrenia: less impairment in reading compared with other skill areas

BACKGROUND

Our study examined the differential performance of cognitive skills in geriatric, cognitively impaired schizophrenic patients (n = 165) with a lengthy course of institutional stay and a poor overall functional outcome. Their relative deficits were compared with a sample of healthy elderly individuals.

METHODS

Schizophrenic patients were matched one-to-one with healthy individuals of the same age and education and compared on a number of measures of cognitive functioning. The schizophrenic patients' old-learning performance was also compared with their educational level only.

RESULTS

Mini-Mental State Examination (Folstein et al 1975) scores of the patients were in the moderately demented range (M = 20.36), and these patients underperformed healthy control subjects by more than 1 to slightly less than 3 standard deviations on measures of memory, praxis, and verbal skills. Wide Range Achievement Test-Revised word-recognition reading scores were found to be at the 10th-grade level, although the patients on average had completed 11 years of formal education.

CONCLUSIONS

These results suggest that even in schizophrenic patients with significant cognitive impairment, reading scores are relatively consistent with educational attainment. These data indicate that poor performance on measures of cognitive functioning in this population does not necessarily occur on measures of old learning.

Clinical, cognitive and functional characteristics of long-stay patients with schizophrenia: a comparison of VA and state hospital patients

Long-stay patients constitute a small proportion of all patients with schizophrenia, but in both VA and state psychiatric systems these patients account for a majority of the costs associated with treatment of the illness. VA and state patients would be expected to differ in several respects, including age at onset and premorbid educational status. Little additional information is available about the differences between these samples. Seventy-four long-stay male patients at a chronic state psychiatric center were compared with 50 male veterans from long-stay psychiatric facilities on positive and negative symptoms, cognitive deficits and functional status. The two samples did not differ on positive symptom severity, but the state patients had more severe negative and cognitive symptoms as well as functional deficits. Of all of the variables measured, deficit in self care was the only variable that entered a stepwise discriminant analysis. The correlation between functional and symptomatic variables was the same in both groups, and the group differences and correlations were not influenced by differences in educational status. These data indicate that VA patients may have reduced severity of functional and cognitive impairments relative to state hospital patients, but that the relationship between the different illness variables was similar in the two groups.

Correlation between elevated levels of amyloid beta-peptide in the brain and cognitive decline

CONTEXT

Alzheimer disease (AD) is characterized neuropathologically by the presence of amyloid beta-peptide (Abeta)-containing plaques and neurofibrillary tangles composed of abnormal tau protein. Considerable controversy exists as to whether the extent of accumulation of Abeta correlates with dementia and whether Abeta alterations precede or follow changes in tau.

OBJECTIVES

To determine whether accumulation of Abeta correlates with the earliest signs of cognitive deterioration and to define the relationship between Abeta accumulation and early tau changes.

DESIGN, SETTING, AND PATIENTS

Postmortem cross-sectional study of 79 nursing home residents with Clinical Dementia Rating (CDR) scale scores of 0.0 to 5.0 who died between 1986 and 1997, comparing the levels of Abeta variants in the cortices of the subjects with no (CDR score, 0.0 [n = 16]), questionable (CDR score, 0.5 [n = 11]), mild (CDR score, 1.0 [n = 22]), moderate (CDR score, 2.0 [n = 15]), or severe (CDR score, 4.0 or 5.0 [n = 15]) dementia.

MAIN OUTCOME MEASURES

Levels of total Abeta peptides with intact or truncated amino termini and ending in either amino acid 40 (A(beta)x-40) or 42 (A(beta)x-42) in 5 neocortical brain regions as well as levels of tau protein undergoing early conformational changes in frontal cortex, as a function of CDR score.

RESULTS

The levels of both A(beta)x-40 and A(beta)x-42 were elevated even in cases classified as having questionable dementia (CDR score = 0.5), and increases of both peptides correlated with progression of dementia. Levels of the more fibril-prone A(beta)x-42 peptide were higher than those of A(beta)x-40 in nondemented cases and remained higher throughout progression of disease in all regions examined. Finally, increases in A(beta)x-40 and A(beta)x-42 precede significant tau pathology at least in the frontal cortex, an area chosen for examination because of the absence of neuritic changes in the absence of disease.

CONCLUSIONS

In this study, levels of total A(beta)x-40 and A(beta)x-42 were elevated early in dementia and levels of both peptides were strongly correlated with cognitive decline. Of particular interest, in the frontal cortex, Abeta was elevated before the occurrence of significant tau pathology. These results support an important role for Abeta in mediating initial pathogenic events in AD dementia and suggest that treatment strategies targeting the formation, accumulation, or cytotoxic effects of Abeta should be pursued.

The longitudinal relationship of clinical symptoms, cognitive functioning, and adaptive life in geriatric schizophrenia

Cognitive dysfunction is increasingly being recognized as a major contributor to the adaptive impairment seen in most patients with schizophrenia. Reported here is a prospective longitudinal evaluation of the relationship between cognitive and adaptive functioning in elderly patients with schizophrenia. It was hypothesized that baseline cognitive and negative, but not positive symptoms, would be predictive of cross-sectional impairment and longitudinal outcome. Subjects were 168 elderly patients with schizophrenia, free of major neurological disorders, who were residents of a long-term psychiatric facility. Subjects were assessed at baseline and again an average of 15months later. The PANSS was used to assess the severity of symptoms of schizophrenia. Cognitive symptoms were assessed using the components of the CERAD cognitive battery. Social and adaptive functioning was assessed using the SAFE scale. Spearman correlations were determined among clinical variables, and the rank ordering of prediction of SAFE scale scores at follow-up was determined using a stepwise regression procedure. At follow-up, adaptive life skills correlated with cognitive performance and negative symptoms (Spearman rho values 0. 41-0.57, all p values <0.0001), but not positive symptoms (r=0.09, n. s.). Among cognitive tasks, verbal learning and memory were most highly correlated with adaptive skills at follow-up. These results confirm and extend previous studies that indicate that cognitive impairments are predictive, both cross-sectionally and longitudinally, of adaptive life skills in persons with schizophrenia. Negative symptoms, but not positive symptoms, were correlated with impaired adaptive skills. Taken together, these results underscore the need to develop more effective treatments for cognitive and negative symptoms in schizophrenia.

A randomized controlled trial of prednisone in Alzheimer's disease. Alzheimer's Disease Cooperative Study

BACKGROUND

Laboratory and epidemiologic studies suggest that anti-inflammatory/immunosuppressive therapy may be useful in the treatment of AD. In preliminary studies, a regimen of low to moderate dose prednisone was found to suppress peripheral inflammatory markers without adverse effects in subjects with AD.

METHODS

We conducted a randomized, placebo-controlled multicenter trial to determine whether prednisone treatment slowed the rate of cognitive decline in AD. The active treatment regimen consisted of an initial dose of 20 mg of prednisone daily for 4 weeks tapered to a maintenance dose of 10 mg daily for 1 year, followed by gradual withdrawal during an additional 16 weeks. The primary outcome measure was the 1-year change in the cognitive subscale of the AD Assessment Scale.

RESULTS

A total of 138 subjects were randomized to the drug and placebo groups. There was no difference in cognitive decline between the prednisone and placebo treatment groups in the primary intent-to-treat analysis, or in a secondary analysis considering completers only. Subjects treated with prednisone showed behavioral decline compared with those in the placebo group.

CONCLUSION

A low-dose regimen of prednisone is not useful in the treatment of AD.

Prevalence and correlates of parkinsonism in an institutionalized population of geriatric patients with chronic schizophrenia

BACKGROUND

Geriatric patients with chronic schizophrenia are at increased risk for parkinsonism and cognitive impairment, but the relationship between the two has been insufficiently studied.

OBJECTIVES

(1) To determine the prevalence of parkinsonism in a cohort of institutionalized geriatric patients with chronic schizophrenia (N=79). (2) To examine the relationship of parkinsonism to potentially relevant variables including cognitive functioning, positive and negative symptoms, sex, age, age at first hospitalization, psychopharmacological regimen and tardive dyskinesia (TD).

METHOD

Tremor, rigidity and bradykinesia were rated on a five-point severity scale. Clinically significant parkinsonism was defined by the unambiguous presence of at least two of those signs. TD was assessed with the Modified Simpson Dyskinesia Scale. Schizophrenic symptoms were rated with the Positive and Negative Syndrome Scale, and cognitive functioning with the Mini-Mental State Examination and the Consortium to Establish a Registry for Alzheimer's Disease battery.

RESULTS

The prevalence of parkinsonism was 19% and was significantly higher in women than in men. Age was a significant predictor of parkinsonism. Independent of age, bradykinesia was significantly correlated with MMSE, fluency and naming. Tremor, rigidity and medication status did not correlate with any cognitive variable assessed. Cognitive measures did not differ between subjects meeting and not meeting criteria for clinically significant parkinsonism. Rigidity and bradykinesia were significantly correlated with negative symptoms but no parkinsonism sign correlated with positive symptoms. Twelve subjects received ratings consistent with both TD and parkinsonism; however, no parkinsonian variable predicted the co-occurrence of TD.

CONCLUSIONS

The present correlations suggest potential overlap among the neural substrates for bradykinesia, cognitive impairment and negative symptoms; however, further research is required to clarify that issue.

Myocardial protection with high-dose beta-blockade in acute myocardial ischemia

OBJECTIVE

The risk of postoperative cardiac dysfunction is markedly increased by emergency coronary artery bypass grafting in the presence of acute myocardial ischemia. High dose beta-blockade during continuous coronary perfusion has been suggested as an alternative to conventional cardioplegia and this technique has been applied successfully in high risk patients for coronary artery bypass grafting (CABG) surgery. This study compared high dose beta-blockade with esmolol to continuous warm blood cardioplegia in a clinically oriented model of acute left ventricular (LV) ischemia and reperfusion.

METHODS

Twelve dogs were subjected to 60 min of regional LV ischemia by left anterior descending branch (LAD) ligation. Cardiopulmonary bypass (CPB) and aortic crossclamp were applied after 45 min of ischemia. Thereafter, high dose beta-blockade during continuous coronary perfusion (ESMO, n = 6) or antegrade continuous warm blood cardioplegia (WBC, n = 6) were maintained for 60 min. Myocardial water content (measured from endomyocardial biopsies using a microgravimetric technique), global LV function (preload recruitable stroke work: PRSW), and regional LV function (echocardiographic wall motion score) were determined at baseline and after weaning from CPB.

RESULTS

During aortic crossclamp interstitial edema formation was significantly higher in the WBC group with an average water gain of 2.2 +/- 0.49 vs. 0.76 +/- 0.12% in the ESMO group. Thereafter, edema resolved in both groups, but myocardial water gain remained significantly higher in the WBC group at 60 and 120 min post CPB (0.98 +/- 0.19 and 1.13 +/- 0.32% vs. 0.07 +/- 0.25 and 0.04 +/- 0.08%). Global LV function was significantly higher in the ESMO group at 60 and 120 min post CPB (PRSW 103 +/- 6 and 94.7 +/- 4.6% of baseline vs. 85.3 +/- 4.9 and 74.7 +/- 7.6% of baseline). However, regional LV function showed no significant difference between groups.

CONCLUSIONS

High-dose beta-blockade during continuous coronary perfusion may allow the surgeon to utilize the advantages of warm heart surgery, while avoiding the interstitial edema formation and temporary cardiac dysfunction associated with continuous warm blood cardioplegia. In high risk patients such as patients with unstable angina or after failed PTCA, high-dose beta-blockade may be an applicable alternative to cardioplegic arrest.

Metabotropic glutamate receptor mRNA expression in the schizophrenic thalamus

BACKGROUND

The central role that the thalamus plays in information processing and sensory integration suggests that its dysfunction may be a factor in the pathophysiology of schizophrenia. Glutamate is a key neurotransmitter in thalamic function, and although all aspects of thalamic glutamate neurotransmission have not been elucidated, transcripts encoding members of each family of the glutamate receptors have been identified in the thalamus. Recently, activation of group II metabotropic glutamate receptors (mGluRs) was demonstrated in rats to ameliorate the behavioral effects associated with exposure to phencyclidine, an uncompetitive NMDA receptor antagonist that can induce psychotic symptoms, suggesting the possibility of mGluR abnormalities in schizophrenia. We investigated whether expression of thalamic mGluR mRNA is altered in this illness.

METHODS

We examined the expression of the transcripts encoding the mGluR1, 2, 3, 4, 5, 7, and 8 receptors in postmortem thalamic tissue samples from elderly schizophrenic and control subjects, using in situ hybridization. We identified six thalamic nuclei in each section (anterior, dorsomedial, lateral dorsal, central medial, reticular, and nuclei of the ventral tier).

RESULTS

There were no differences between elderly schizophrenic and control subjects in the expression of mGluR1, 2, 3, 4, 5, 7, or 8 transcript levels in any of these six thalamic nuclei.

CONCLUSIONS

mGluR mRNA expression is not abnormal in the thalamus of patients with schizophrenia. The modulatory roles proposed for mGluRs, and the potentially important relationship between mGluRs and NMDA receptors, suggest that mGluRs may be involved in the pathophysiology of schizophrenia, but this is not detectable at this level of gene expression.

The role of norepinephrine in the pathophysiology of cognitive disorders: potential applications to the treatment of cognitive dysfunction in schizophrenia and Alzheimer's disease

The role of noradrenergic neurotransmission in normal cognitive functions has been extensively investigated, however, the involvement of noradrenergic functions in the cognitive impairment associated with schizophrenia and Alzheimer's disease has not been as intensively considered. The limited ability of atypical antipsychotics to treat the cognitive impairment of schizophrenia, and cholinomimetics to treat the cognitive impairment of Alzheimer's disease, may be related to the influence of a multiplicity of neurotransmitter abnormalities including noradrenergic dysfunction, which these treatments do not address. The evidence of noradrenergic dysfunction occurring concomitantly with dopamine dysfunction in schizophrenia and acetylcholine dysfunction in Alzheimer's disease supports therapeutic approaches using noradrenergic drugs in combination with neuroleptics and cholinesterase inhibitors, respectively, to enhance the treatment of cognitive impairment. Given the results of animal and human studies, it appears that alpha-2A agonists may be the optimal choice for this purpose.

Neuropeptide abnormalities in patients with early Alzheimer disease

BACKGROUND

Deficits in somatostatin-like immunoreactivity (SLI) and corticotropin-releasing factor immunoreactivity (CRF-IR) are well recognized as prominent neurochemical deficits in Alzheimer disease (AD). The question of whether these profound neuropeptidergic deficits found in patients with end-stage disease extend into those with much earlier disease is relatively unanswered. To determine the relation between level of SLI and CRF-IR in different cerebrocortical regions to the earliest signs of cognitive deterioration in AD.

METHODS

We examined SLI and CRF-IR levels in 9 neocortical brain regions of 66 elderly patients in a postmortem study of nursing home residents who had either no significant neuropathologic lesions or lesions associated only with AD. Patients were assessed by the Clinical Dementia Rating scale (CDR) to have no dementia or questionable, mild, or moderate dementia, and were compared with 15 patients with severe dementia.

RESULTS

Both CRF-IR and SLI were significantly reduced in the cortices of patients with the most severe dementia, but only the levels of CRF-IR were reduced in those with mild (CDR = 1.0) and moderate dementia (CDR = 2.0). Levels of CRF-IR and SLI correlated significantly with CDR, but this correlation was more robust for CRF-IR and persisted even when severely cognitively impaired patients were eliminated from analysis.

CONCLUSIONS

Although SLI and CRF-IR levels are significantly reduced in patients with severe dementia, only CRF-IR is reduced significantly in the cortices of those with mild dementia. Thus, CRF-IR can serve as a potential neurochemical marker of early dementia and possibly early AD.

Cognitive and functional changes with aging in schizophrenia

The variation in functional outcome in schizophrenia appears to be exaggerated in late life. The cognitive and functional deficits commonly seen in younger schizophrenic patients appear to worsen in some cases in late life, while others patients appear to have a stable course of illness without functional decline, and still other patients have been reported to have essentially no residual symptoms in their later years. Cognitive and functional deficits appear to worsen more significantly in patients with a lifetime course of severe functional deficit. Despite the profound functional and cognitive deficits in these patients, neuropathologic studies have found no evidence of typical causes of severe cognitive impairments. This paper reviews the current findings on cognitive and functional changes in aging in schizophrenia, with a specific focus on patients with a poor lifetime functional outcome.

An erythropoietin fusion protein comprised of identical repeating domains exhibits enhanced biological properties

The hematopoietic growth factor erythropoietin (Epo) initiates its intracellular signaling cascade by binding to and inducing the homodimerization of two identical receptor molecules. We have now constructed and expressed in COS cells a cDNA encoding a fusion protein consisting of two complete human Epo domains linked in tandem by a 17-amino acid flexible peptide. On SDS-polyacrylamide gel electrophoresis, the Epo-Epo fusion protein migrated as a broad band with an average apparent molecular mass of 76 kDa, slightly more than twice the average apparent molecular mass of Epo, 37 kDa. Enzymatic N-deglycosylation resulted in an Epo-Epo species that migrated on SDS-polyacrylamide gel electrophoresis as a narrow band with an average apparent molecular mass of 39 kDa. The specific activity of the Epo-Epo fusion protein in vitro (1,007 IU/microgram; 76 IU/pmol) was significantly greater than that of Epo (352 IU/microgram; 13 IU/pmol). Moreover, secretion of Epo-Epo by COS cells was 8-fold greater than that of Epo. Subcutaneous administration of a single dose of Epo-Epo to mice resulted in a significant increase in red blood cell production within 7 days. In contrast, administration of an equivalent dose of conventional recombinant Epo was without effect. The pharmacokinetic behavior of Epo-Epo differed significantly from that of Epo. The results suggest that Epo-Epo may have important biological and therapeutic advantages.

Genetic epidemiological study of maternal and paternal transmission of Alzheimer's disease

Recent evidence for mitochondrial mutations associated with Alzheimers disease (AD) suggests the possibility of maternal transmission of this illness. We investigated this hypothesis by examining, in a variety of ways, the risk of a primary progressive dementia (PPD) in the parents (n = 650) and siblings (n = 1,220) of 325 AD probands. The results did not support maternal transmission in AD: The mothers of AD probands were not at greater risk of PPD than the fathers or the sisters of AD probands; the offspring of affected mothers were not at greater risk than the offspring of affected fathers or families with no affected parent; and, after selecting those proband families with evidence for increased familial loading, such families did not more frequently have affected mothers than fathers. In contrast, the cumulative risk of PPD in fathers of AD probands, while similar to that of mothers, was significantly increased over the brothers of AD probands. In addition, the cumulative risk curve of PPD in the offspring of affected fathers was significantly higher than the offspring of no affected parents. While no evidence for maternal transmission in AD was observed, unexpectedly, we did find evidence of increased paternal transmission.

Neurofibrillary tangles in nondemented elderly subjects and mild Alzheimer disease

BACKGROUND

The relationship between neuropathological lesions and mild, "preclinical," cognitive impairments of Alzheimer disease is poorly understood. Identification of the lesions that are most closely associated with the earliest symptoms of Alzheimer disease is crucial to the understanding of the disease process and the development of treatment strategies to affect its progression.

DESIGN AND MAIN OUTCOME MEASURES

We examined the extent of neurofibrillary tangles (NFTs) in 4 neocortical regions, the hippocampus, the entorhinal cortex, and the amygdala in 65 elderly subjects with no dementia, questionable dementia, mild dementia, or moderate dementia as assessed using the Clinical Dementia Rating Scale (CDR).

SETTING AND PATIENTS

Postmortem study of nursing home residents.

RESULTS

Neurofibrillary tangles were present in the entorhinal cortex and the hippocampus of all subjects, including those without cognitive deficits. Neocortical NFTs were mostly absent in the nondemented (CDR score, 0.0) subjects. The density of NFTs in the questionably demented (CDR score, 0.5) subjects was not significantly increased (P>.20) relative to the nondemented group in any of the brain regions studied. Significant increases (P<.04) in NFT density become apparent first in the amygdala and the temporal cortex in subjects rated to be mildly impaired (CDR score, 1.0). By the time that cognitive impairments were judged to be moderately severe (CDR score, 2.0), all regions of the brain examined, except for the occipital cortex, were significantly (P<.05) involved.

CONCLUSIONS

Some NFTs are present in the entorhinal cortex and hippocampus of most elderly individuals irrespective of their cognitive status, but the density of NFTs increases as a function of dementia severity.

Regulated expression and functional role of the transcription factor CHOP (GADD153) in erythroid growth and differentiation

The hematopoietic growth factor erythropoietin (Epo) triggers changes in the expression of genes that encode important regulators of erythroid cell growth and differentiation. We now report that Epo markedly upregulates chop (gadd153) expression and that this transcription factor plays a role in erythropoiesis. Using a differential hybridization assay, we isolated a full-length cDNA of chop as an Epo upregulated gene in Rauscher murine erythroleukemia cells. RNase protection assays demonstrated that Epo or dimethyl sulfoxide induction increased steady-state mRNA levels 10- to 20-fold after 24 to 48 hours. Western blot analysis confirmed a marked increase in CHOP protein. Among the other c/ebp family members, only c/ebp beta was also upregulated during erythroid differentiation. Among normal hematopoietic cells examined, steady-state mRNA levels were highest in erythroid cells, with levels peaking during terminal differentiation. Transient overexpression of chop in Rauscher cells resulted in a significant increase in Epo- or dimethyl sulfoxide (DMSO)-induced hemoglobinization, further linking chop upregulation to erythroid differentiation. Artificial downregulation of chop in normal murine bone marrow cells with antisense oligodeoxynucleotides inhibited colony-forming unit-erythroid (CFU-E)-derived colony growth in a concentration-dependent manner. Burst-forming unit-erythroid (BFU-E)-derived colony growth was not affected. Using a Far Western type of analysis, we detected several potential CHOP binding partners among the nuclear proteins of Rauscher cells. Importantly, the number and relative abundance of these proteins changed with differentiation. The results strongly suggest that CHOP plays a role in erythropoiesis, possibly through interactions with both C/EBP and non-C/EBP family members.

Genetic antecedents of dopamine dysfunction in schizophrenia

BACKGROUND

Relatives of schizophrenic probands frequently manifest attenuated features of this illness including the negative symptoms and the milder positive psychotic symptoms. These two symptom dimensions are hypothesized to be associated with decreased and increased brain dopamine (DA) functions, respectively, raising the possibility that DA abnormalities may be present in the relatives of schizophrenic probands.

METHODS

Plasma homovanillic acid (HVA), the major DA metabolite and an indicator of brain DA activity, was measured in nonpsychotic, physically healthy first-degree relatives (n = 55) of schizophrenic probands and in normal subjects (n = 20) without a family history of schizophrenia.

RESULTS

Plasma HVA inversely correlated with negative symptoms and positively correlated with attenuated positive symptoms. Also, relatives had decreased plasma HVA compared to normal subjects, consistent with the fact that these relatives are characterized by negative symptoms. These findings were not related to major peripheral factors that could affect plasma HVA suggesting that the findings may reflect changes in brain DA activity.

CONCLUSIONS

Negative symptoms indicating a genetic diathesis to schizophrenia in relatives may have a biologic basis in reduced DA activity and the DA dysfunction of schizophrenia may have genetic antecedents. This opens an important new avenue for further study of DA in this illness.

Contamination of lymph from the major prenodal cardiac lymphatic in dogs

Cannulation of the canine major prenodal cardiac lymphatic (MPCL) is the most common approach for the investigation of myocardial lymphatic function. However, the assumption that the MPCL drains pure cardiac lymph has been questioned. We studied variations of MPCL anatomy and investigated whether noncardiac lymph is drained by this lymphatic. After dye was injected into the lungs and left ventricular myocardium in 21 dogs, dissection of the cardiac lymphatic system yielded 3 anatomic variations. In variations 1 and 2 (81% of dogs), a mixture of cardiac and pulmonary lymph was drained via the MPCL. In variation 3 (19% of dogs) no connection was found between MPCL and pulmonary lymphatics. In variations 1 and 2, alteration of tidal volume resulted in significant changes of lymph flow rate. The pulmonary contribution to MPCL lymph flow was estimated as 34% in variation 2. We conclude that MPCL lymph may contain not only cardiac lymph but also significant pulmonary contamination. This finding should be considered in the interpretation of lymph data from cannulation of the canine MPCL.

Cholinergic markers in elderly patients with early signs of Alzheimer disease

CONTEXT

A central tenet of Alzheimer disease (AD) is the loss of cortical cholinergic function and cholinergic markers in postmortem brain specimens. Whether these profound deficits in cholinergic markers found in end-stage patients are also found in patients with much earlier disease is not known.

OBJECTIVE

To determine whether cholinergic deficits in AD precede, follow, or occur in synchrony with the earliest signs of cognitive deterioration.

DESIGN, SETTING, AND PATIENTS

Postmortem study of nursing home residents with Clinical Dementia Rating (CDR) Scale scores of 0.0 to 2.0 and 4.0 to 5.0 who underwent autopsy between 1986 and 1997, comparing the activity of the cholinergic marker enzymes in the cortices of 66 elderly subjects with no (CDR score = 0.0; n = 18), questionable (CDR score = 0.5; n = 11), mild (CDR score = 1.0; n = 22), or moderate (CDR score = 2.0; n = 15) dementia vs subjects with severe dementia (CDR score = 4.0-5.0; n = 15).

MAIN OUTCOME MEASURES

Activity of the cholinergic marker enzymes choline acetyltransferase and acetylcholinesterase in 9 neocortical brain regions.

RESULTS

The activity of choline acetyltransferase and acetylcholinesterase in 9 neocortical brain regions did not differ significantly in subjects with CDR scores of 0.0 to 2.0, but was significantly lower in subjects with severe dementia (CDR score = 4.0-5.0). Choline acetyltransferase levels were significantly correlated with severity of neuropathological lesions of AD, as measured by density of neuritic plaques and neurofibrillary tangles.

CONCLUSIONS

Although neocortical cholinergic deficits are characteristic of severely demented AD patients, in this study, cholinergic deficits were not apparent in individuals with mild AD and were not present until relatively late in the course of the disease. These results suggest that patients with more severe disease should be a target for cholinergic treatment.

The impact of behavioral impairment of functional ability in Alzheimer's disease

This study sought to determine the relationship between behavioral disturbance and functional status in a longitudinally studied sample of patients with Alzheimer's disease (AD). One hundred and forty-nine patients meeting NINCDS-ADRDA criteria for probable AD were followed for an average of 37.3 months, with follow-up assessments every 6 months. Subjects were seen at the Alzheimer's Disease Research Center clinics at the Mt Sinai Medical Center, New York, and the Veterans Affairs Medical Center, Bronx, New York. Measures included the Physical and Self-Maintenance Scale (PSMS) and Instrumental Activities of Daily Living Scale (IADLS) of Lawton and Brody and the cognitive and non-cognitive subscales of the Alzheimer's Disease Assessment Scale (ADAS). For each patient the assessment at which they had their most severe non-cognitive symptoms as measured by the non-cognitive part of the ADAS (ADAS-NC) was determined. ADAS-NC scores at that assessment were correlated with IADLS and PSMS scores at the same assessment and at the next assessment 6 months later. While there was some modest association of ADAS-NC scores with functional impairment using pairwise correlation coefficients, none of the correlations remained significant when the severity of cognitive impairment was controlled statistically. Findings were not significantly changed when drug status was controlled. These results suggest that behavioral disturbance, while very troubling to caregivers and patients, does not substantially worsen functional ability beyond the contribution of cognitive impairment in AD. Together with previous results indicating that non-cognitive symptoms in AD are episodic and fluctuating rather than progressive, the present data suggest that interventions for non-cognitive disturbances in AD should be viewed as ways to increase patient comfort, safety and ease of care and not as ways to improve functional autonomy. The latter can be achieved only by improving the progressive cognitive deficits of AD.

Test-retest reliability of psychological and neurobehavioral tests self-administered by computer

A series of 12 psychological and 7 neurobehavioral performance tests were administered twice to a nonclinical normative sample with 1 week between administrations. The tests were presented in a self-administered computerized format. One week test-retest reliabilities were comparable to conventional administration formats. The results suggest that individual test reliability is not affected when tests are administered as part of an extensive multi-measure battery. Computer administered test reliability coefficients also were compared to a Mixed Format (computer-conventional) administration with mixed format reliabilities generally similar to the reliabilities of published conventional tests but also generally lower than same format testing. Compared to psychological test reliability, neurobehavioral test reliability appeared more vulnerable to decreases with mixed format testing. These conclusions should not be generalized to all computer implemented tests as the qualities of the test implementation will affect the outcome.

Identifying families with likely genetic protective factors against Alzheimer disease

Elderly individuals who lived beyond the age of 90 years without dementia were hypothesized to have increased concentrations of genetic protective factors against Alzheimer disease (AD), conferring a reduced liability for this disease relative to less-aged nondemented elderly. However, testing this hypothesis is complicated by having to distinguish such a group from those who may lack genetic risk factors for AD, have had protective environmental exposures, or have escaped dementia for other reasons. Probands carrying genetic protective factors, however, should have relatives with lower illness rates not only for earlier-onset disease, when genetic risk factors are a strong contributing factor to the incidence of AD, but also for later-onset disease, when the role of these factors appears to be markedly diminished. AD dementia was assessed through family informants in 6,660 first-degree relatives of 1,049 nondemented probands aged 60-102 years. The probands were grouped by age (60-74, 75-89, and 90-102 years), and the cumulative survival from AD and 10-year-age-interval hazard rates of AD were calculated in their first-degree relatives. Cumulative survival from AD was significantly greater in the relatives of the oldest proband group (aged 90-102 years) than it was in the two younger groups. In addition, the reduction in the rate of illness for this group was relatively constant across the entire late life span. The results suggest that genetic factors conferring a lifelong reduced liability of AD may be more highly concentrated among nondemented probands aged >/=90 years and their relatives. Efforts to identify protective allele-bearing genes that are associated with very late-onset AD should target the families of nonagenarians and centenarians.

Neurobehavioral deficits in Persian Gulf veterans: evidence from a population-based study. Portland Environmental Hazards Research Center

Reports of low-concentration nerve gas exposures during the Persian Gulf War have spurred concern about possible health consequences and refocused interest on the symptoms reported by many returning military veterans. The Portland Environmental Hazards Research Center is studying veterans from the Northwest USA who report persistent, unexplained "Persian Gulf" symptoms (cases) or who do not report those symptoms (controls). Of the first 101 veterans studied, cases differed substantially from controls on a broad range of psychological tests indicative of increased distress. A subgroup of cases was identified with objective deficits on neurobehavioral tests of memory, attention, and response speed.

Variation in tau, the time constant for isovolumic relaxation, along the left ventricular base-to-apex axis

Tau (tau), the time constant for isovolumic relaxation, is often used as a measure of cardiac diastolic function. However, several methods of calculating tau have been published which may produce different results and, thereby, different conclusions. The purpose of this study was to determine if the method of tau calculation effects the results when left ventricular pressure (LVP) is measured at different positions along the base-to-apex axis. In 16 dogs, we measured LVP at 6 positions along the base-to-apex axis. We calculated tau using three different methods: 1) a monoexponential model (P(t) = [P0-Pasym]eAt + Pasym, where t = time, P0 = LVP at t = 0, Pasym is asymptotic pressure as t-->infinity, A is -1/tau) with a zero asymptote 2) a monoexponential model with a variable asymptote in which the monoexponential decay equation is differentiated with respect to time and substituted into the original equation so that dP/dt vs. LVP is A (-1/tau), and 3) a monoexponential decay model with variable asymptote in which Pasym and A are varied until the best fit line is reached by minimizing the residual sum of squares. When tau is calculated using method 1, tau measured at the LV base is 98.01% +/- 8.85% of tau at the apex. If calculated using method 2, tau measured at the LV base was 75.46 +/- 39.4% of tau measured at the apex. When method 3 is used for tau calculations, base tau increases to 117.76 +/- 4.91% of the apical tau. We conclude: 1) the method used to calculate tau will effect the results and, thus, conclusions drawn from tau data. 2) When using Method 3, which appears to be the best method for tau calculation, tau increases at the LV base compared to the apex.

CSF beta-amyloid, cognition, and APOE genotype in Alzheimer's disease

OBJECTIVES

We examined the relationship between CSF amyloid beta peptide (A beta) concentration and AD severity in 31 probable AD patients and explored whether APOE genotype modifies this relationship.

BACKGROUND

A beta deposition in AD brains has been correlated with disease severity and with APOE-epsilon4 allele frequency. Few studies have examined the effects of APOE genotype on the relationship between CSF A beta and disease severity in an antemortem sample.

METHODS

Patients carried the clinical diagnosis of probable AD and did not have serious medical illness, current or past diagnosis of mood disorder, schizophrenia or alcoholism, or current psychotic features. The Mini-Mental State Examination (MMSE) was administered to the patient within 3 months of CSF collection. CSF was analyzed for A beta1-40 and A beta1-42 by sandwich ELISAs, and APOE genotype was determined by PCR run from blood. Correlations were performed between MMSE score and A beta1-40 and A beta1-42 concentrations while controlling for potential confounding variables.

RESULTS

CSF measures of A beta1-40 and A beta1-42 concentrations were correlated with each other (r = 0.56, df = 28, p < 0.01). CSF A beta1-40 and A beta1-42 concentrations were positively correlated with MMSE score. The negative association between CSF A beta measures and disease severity remained significant after controlling for age (A beta1-40 and MMSE score: r = 0.46, df = 28, p = 0.01; A beta1-42 and MMSE score: r = 0.35, df = 28, p = 0.05). Among the APOE-epsilon3/3 homozygotes there was a significant positive correlation only between A beta1-42 and MMSE score (A beta1-42, r = 0.94, p = 0.02; A beta1-40, r = 0.79, p = 0.11).

CONCLUSIONS

We hypothesize that an increased deposition of A beta in plaques results in decreased CSF A beta concentration. The stronger relationship between MMSE score and CSF A beta, specifically in APOE-epsilon3/3 homozygotes, suggests that patients with APOE-epsilon3/3 genotype may have different pathogenic mechanisms than the other genotypes for A beta deposition or clearance.

Alzheimer's disease: seeking new ways to preserve brain function. Interview by Alice V. Luddington

Alzheimer's disease (AD) is characterized in the brain by the deposition of amyloid protein outside the neuron, resulting in the formation of plaques, and inside the neuron with neurofibrillary tangles. It is not yet known what causes these pathologic changes, although age and genetics are major risk factors. The cholinesterase inhibitors tacrine and donepezil block acetylcholinesterase and therefore preserve the neurotransmitter acetylcholine. Three other investigational cholinesterase inhibitors are rivastigmine, metrifonate, and galanthamine. Existing therapies being studied for use in AD include vitamin E, estrogen preparations, and anti-inflammatory agents. The physician's role is to care for both the AD patient and the family, which are profoundly affected by this disease.

Convergence of cognitive and adaptive decline in late-life schizophrenia

Cognitive impairment has proven to be a major predictor of overall functional deficit in schizophrenia. Despite the significant impairments seen on the part of many patients with schizophrenia that implicate decline at some point in time, there have been no longitudinal studies of adaptive decline in patients with schizophrenia. In this study, 57 geriatric patients with chronic schizophrenia were examined with measures of clinical symptoms, cognitive impairments, and adaptive functioning while living in a chronic psychiatric hospital and followed up an average of two and a half years after their referral to nursing home care. Cognitive functioning and adaptive functioning both declined over the follow-up period, whereas there was no change in schizophrenic symptoms. Changes in cognitive functioning accounted for 25% of the variance in adaptive decline, whereas the baseline severity of cognitive impairment and schizophrenia symptoms were uncorrelated with adaptive decline. These data indicate that cognitive decline may predict deterioration in overall functional status and imply that treatment of cognitive impairment might have a beneficial effect on global functional status.

Cognitive decline in late-life schizophrenia: a longitudinal study of geriatric chronically hospitalized patients

BACKGROUND

Geriatric schizophrenic patients with a chronic course of institutionalization manifest cognitive and functional impairments that implicate decline at some time point after the onset of illness. The rate of change in cognitive and functional status in these patients has not yet been identified with a longitudinal study.

METHODS

Three hundred and twenty-six schizophrenic patients entered a 30-month follow-up study with two separate assessments of the patients. Overall functional and cognitive status was indexed with the Clinical Dementia Rating (CDR). Survival analysis was used to examine changes in cognitive and functional status, including worsening for the less impaired patients and improvements on the part of more impaired patients.

RESULTS

Approximately 30% of the patients who had baseline scores in the less impaired range manifested a worsening of their CDR ratings to a score of 2.0 (moderate) or more severe, whereas only 7% of the sample with lower scores at baseline appeared to improve in their functioning. Several characteristics of the patients at baseline assessment predicted increased risk for cognitive and functional decline, including lower levels of education, older age, and more severe positive symptoms.

CONCLUSIONS

Cognitive and functional decline can be detected in a short-term follow-up in a subset of geriatric long-stay patients with schizophrenia. This decline appears distributed across patients and not due to the presence of progressive degenerative dementing conditions. Later research will have to identify the causes of this decline, possibly on the basis of the risk factors identified in this study.

Pharmacologic strategies for augmenting cognitive performance in schizophrenia

There is recognition that the cognitive symptoms of schizophrenia have the most substantial impact on illness outcome. Domains of cognition reported to be significantly affected include serial learning, executive function, vigilance, and distractibility, to name a few. Dopamine activity at D1 receptors mediates many cognitive processes subserved by the prefrontal cortex (PFC), particularly working memory. The number of D1 receptors in the PFC is decreased in schizophrenics and is unaffected by chronic administration of typical neuroleptics. Therefore, medications that increase dopamine in the PFC, such as atypical neuroleptics, or that directly activate the D1 receptor may prove useful in the remediation of prefrontal-dependent cognitive deficits in schizophrenia. Decreased levels of cortical norepinephrine (NE) are associated with impaired learning and working memory in animal models, and can be reversed by drugs that restore NE activity. More specifically, alpha-2 adrenergic receptor agonists have been particularly effective in improving delayed response performance in young monkeys with localized 6-hydroxydopamine lesions in the PFC. Furthermore, human postmortem studies have demonstrated decreased NE in the frontal cortex of demented schizophrenic patients. Therefore, alpha-2 receptor agonists hold promise as drugs to improve cognitive performance on tasks dependent upon PFC function in schizophrenics. Finally, the finding that cortical choline acetyl transferase activity correlates with Clinical Dementia Rating scores in schizophrenic patients and that cholinomimetic drugs enhance cognition in healthy subjects suggests that cholinergic drugs may also treat cognitive symptoms in schizophrenia. Two potential types of cholinomimetics for use in schizophrenics are the acetylcholinesterase inhibitors and M1/M4 muscarinic agonists, both of which increase cortical cholinergic activity.

AMPA receptor binding and subunit mRNA expression in prefrontal cortex and striatum of elderly schizophrenics

The dopamine hypothesis of schizophrenia has recently evolved into a model of dysfunctional integration between cortical and subcortical dopaminergic activity. Anatomical data suggest that regional alterations in dopaminergic activity may be linked by means of the rich glutamatergic innervation of the striatum by corticostriatal projections, suggesting a potential role for glutamatergic dysfunction in schizophrenia. Although pharmacological data have implicated the NMDA subtype of glutamate receptor in this illness, disturbance in AMPA receptor expression could potentially lead to the NMDA receptor hypoactivity hypothesized in schizophrenia. To address this possibility, we examined AMPA receptor binding and subunit mRNA levels in prefrontal cortex and striatum of schizophrenics and matched controls. There were no significant differences in AMPA receptor binding or subunit mRNA levels in either prefrontal cortical or striatal regions of schizophrenics. Furthermore, AMPA receptor expression did not seem to be regulated by chronic antipsychotic drug exposure, when neuroleptic treated and drug-free schizophrenics were analyzed separately. These data do not support a role for altered AMPA receptor expression in cortex and striatum in schizophrenia.

Future therapeutic approaches to Alzheimer's disease

As palliative treatments for Alzheimer's disease proliferate, the focus of therapeutics turns to drugs with the potential to alter course. Evidence is reviewed, suggesting that there is biological plausibility to utilizing anti-inflammatory agents, antioxidants, free-radical scavengers, estrogen preparations, and perhaps cholinomimetics. This range of possibilities leads to an optimistic assessment of the likelihood for altering the course or delaying the onset of Alzheimer's disease.

The relationship between apolipoprotein E, dementia, and vascular illness

The purpose of this study was to concurrently assess the relationship of Apolipoprotein E (APOE) with both dementias and vascular illnesses in the very old. Nine hundred and fifty nine subjects (mean age 85 years) in a long-term care facility were genotyped and cognitively tested with the Mini Mental State Exam. All subjects were studied for the relationship of APOE with atherosclerotic heart disease, hypertension, or stroke without concomitant dementia. Four hundred fifty individuals met criteria for inclusion into one of the following groups: Alzheimer's disease (n = 318), vascular dementia (n = 49), or not demented controls (n = 83) and were investigated for the relationship between APOE and these diagnostic categories. APOE epsilon4 was not associated with atherosclerotic heart disease, hypertension, or stroke without concomitant dementia. The APOE epsilon3 allele was more common in men with atherosclerotic heart disease. In contrast, the APOE epsilon4 allele was more common in patients with Alzheimer's disease (22%) and vascular dementia (26%) than in not demented controls (7%). APOE epsilon4 is associated with dementias in the very old, whereas its relationship with either peripheral or central nervous system vascular disease without dementia is not as robust.

Regional distribution of neuritic plaques in the nondemented elderly and subjects with very mild Alzheimer disease

BACKGROUND

Identification of the neuropathological lesions that are most closely associated with the earliest symptoms of Alzheimer disease (AD) is crucial to the understanding of the disease process and the development of treatment strategies to affect its progress. Do the classical neuropathological lesions of AD precede, follow, or occur in synchrony with the earliest signs of cognitive deterioration?

DESIGN AND OUTCOME MEASURES

We examined the extent of neuritic plaque (NP) formation in 5 neocortical regions and the hippocampus, entorhinal cortex, and amygdala in 66 elderly subjects with no dementia, questionable dementia, or mild dementia as assessed using the Clinical Dementia Rating Scale (CDR).

SETTING AND PATIENTS

Postmortem study of nursing home residents.

RESULTS

Even questionable dementia (CDR, 0.5) was associated with a significant (P = .04) increase in neocortical NP density. The density of NPs increased further with increasing dementia severity in all brain regions examined. However, subjects with questionable dementia or definite but mild dementia did not differ significantly from each other. Density of NPs was nearly maximal in subjects with moderate dementia (CDR = 2.0), suggesting that other neuropathological changes may be responsible for cognitive deficits beyond this level. Dementia severity correlated significantly with the density of NPs in all brain regions examined (r range, 0.47-0.56; P < .001), even when subjects with a CDR of 0 were excluded.

CONCLUSIONS

These findings are consistent with the hypothesis that NPs are among the earliest neuropathological lesions in AD. Even very mild or questionable dementia is associated with increased density of neocortical NPs that do not distinguish between clinically questionable vs definite dementia.

Postmortem studies in schizophrenia

The past decade has seen renewed interest in the neuropathology of schizophrenia. The advent of new postmortem techniques and functional imaging, along with a greater understanding of the neuropsychology of schizophrenia, have provided many new clues to the nature of the underlying brain dysfunction in this disorder. There has also been a greater understanding of the presence of severe cognitive dysfunction among many elderly persons with schizophrenia. In this article, a series of investigations are described that seek to answer basic questions about the neuropathology of schizophrenia, in particular as it pertains to cognitive impairment. The first study describes neuropathological findings in 100 consecutively autopsied persons with schizophrenia, the majority of whom had had detailed antemortem assessments. Results from this first study prompted the conclusion that schizophrenia is not characterized by classical, histologically identifiable neuropathology. Moreover, most cases of dementia in schizophrenia are probably not the result of neuropathologically identifiable dementing illnesses. The next four studies examined chemical markers that are altered in Alzheimer's disease and some other dementing conditions and have also been suggested to be abnormal in schizophrenia: choline acetyltransferase, catecholamines and indolamines, neuropeptides, and synaptic proteins. Schizophrenia cases as a group did not show a cholinergic deficit; nor did they differ from elderly comparison cases with respect to cortical catecholamines and indolamines. Among the schizophrenia cases, however, cognitive impairment was negatively correlated with choline acetyltransferase activity. Those with cognitive impairment showed evidence of cortical noradrenergic and serotonergic deficits. Neuropeptide deficits were also present in schizophrenia, but their pattern differed from that seen in Alzheimer's disease. Increased synaptic protein activity was found in the cingulate cortex of persons with schizophrenia, and this activity was correlated with schizophrenia symptoms. From this second series of studies, it was concluded that some biological measures in schizophrenia may be related to cognitive impairment (e.g., cortical amines), whereas others may be related to diagnosis (e.g., neuropeptide deficits). In addition, synaptic organization may correlate with schizophrenia symptoms.

Mild traumatic brain injury does not modify the cerebral blood flow profile of secondary forebrain ischemia in Wistar rats

The rat hippocampus is hypersensitive to secondary cerebral ischemia after mild traumatic brain injury (TBI). An unconfirmed assumption in previous studies of mild TBI followed by forebrain ischemia has been that antecedent TBI did not alter cerebral blood flow (CBF) dynamics in response to secondary ischemia. Using laser Doppler flowmetry (LDF), relative changes in regional hippocampal CA1 blood flow (hCBF) were recorded continuously to quantitatively characterize hCBF before, during, and after 6 min of forebrain ischemia in either normal or mildly traumatized rats. Two experimental groups of fasted male Wistar rats were compared. Group 1 (n = 6) rats were given 6 minutes of transient forebrain ischemia using bilateral carotid clamping and hemorrhagic hypotension. Group 2 (n = 6) rats were subjected to mild (0.8 atm) fluid percussion TBI followed 1 h after trauma by 6 min of transient forebrain ischemia. The laser Doppler flow probe was inserted stereotactically to measure CA1 blood flow. The electroencephalogram (EEG) was continuously recorded. During the forebrain ischemic insult there were no intergroup differences in the magnitude or duration of the decrease in CBF in CA1. In both groups, CBF returned to preischemic values within one minute of reperfusion but traumatized rats had no initial hyperemia. There were no intergroup differences in the CBF threshold when the EEG became isoelectric. These data suggest that the ischemic insult was comparable either with or without antecedent TBI in this model. This confirms that this model of TBI followed by forebrain ischemia is well suited for evaluating changes in the sensitivity of CA1 neurons to cerebral ischemia rather than assessing differences in relative ischemia.

Symptoms, cognitive functioning, and adaptive skills in geriatric patients with lifelong schizophrenia: a comparison across treatment sites

OBJECTIVE

Although many geriatric patients with schizophrenia have been referred to nursing home care, little is known about their characteristics. Across nursing home and chronic hospital settings, the authors directly assessed poor outcome geriatric patients with schizophrenia and contrasted their cognitive, symptomatic, and adaptive functioning to that of acutely admitted patients with a better outcome over the lifetime course of the illness.

METHOD

The subjects were 97 chronically hospitalized patients with schizophrenia, 37 patients with chronic schizophrenia who lived in nursing homes, and 31 acutely admitted geriatric patients with schizophrenia. These patients were rated with the Positive and Negative Syndrome Scale, tested with a neuropsychological battery, evaluated with the Mini-Mental State examination, and rated on a scale of social and adaptive deficits, the Social Adaptive Functioning Evaluation scale.

RESULTS

Each group of patients proved discriminable from the other two: nursing home patients displayed the most severe adaptive deficits, and acutely admitted patients were the least cognitively impaired. Cognitive impairment was the strongest predictor of adaptive deficits for all three groups, and negative symptom differences among the groups were smaller than differences in cognitive impairment. Nursing home patients had the least severe positive symptoms, and the acutely ill and chronic hospital patients did not differ on positive symptoms.

CONCLUSIONS

Cognitive impairment is a predictor of both overall outcome and specific adaptive deficits. These data suggest that interventions aimed at cognitive impairment may have an impact on overall functional status. In comparison, positive symptom severity is less strongly correlated with overall adaptive outcome and is uncorrelated with specific deficits in adaptive skills.

Tardive dyskinesia in a chronically institutionalized population of elderly schizophrenic patients: prevalence and association with cognitive impairment

BACKGROUND

Chronically hospitalized geriatric inpatients with schizophrenia are at particular risk for both tardive dyskinesia (TD) and cognitive impairment but have been insufficiently studied in this regard. Similarly, the relationship between TD and cognitive impairment has not be adequately addressed in this population.

OBJECTIVES

(1) To determine the prevalence of TD in a cohort of chronically institutionalized schizophrenic geriatric inpatients. (2) To examine the relationship between the manifestations of TD in various body regions and several potentially related variables including current pharmacological regimen, age, age at first hospitalization and cognitive status.

METHOD

TD was assessed by the Modified Simpson Dyskinesia Scale and cognitive status by the Mini-Mental State Examination (MMSE). The relationship between manifestations of TD and other variables was examined by t-tests, ANOVA, MANOVA and correlational analysis.

RESULTS

The prevalence of TD was 60%. Prevalence increased with age but was not related to current antipsychotic or anticholinergic regimen. Mean MMSE score did not differ between groups of patients with and without TD as defined by the criteria of Schooler and Kane (1982); however, the mean MMSE score was significantly (p < 0.0004) lower in subjects with orofacial TD as defined by Waddington and Youssef (1996), and the difference was not entirely accounted for by the older age of the latter group.

CONCLUSIONS

TD and cognitive impairment both increase with age. However, TD alone does not account for the severity of cognitive impairment in this population. The present study provides further support for the hypothesis that the correlation between TD and cognitive impairment holds primarily for the orofacial manifestations of TD.

Increasing the colloid osmotic pressure of cardiopulmonary bypass prime and normothermic blood cardioplegia minimizes myocardial oedema and prevents cardiac dysfunction

Our recent work demonstrated that normothermic continuous antegrade blood cardioplegia results in cardiac dysfunction related to myocardial oedema. This oedema was partially due to increased myocardial microvascular fluid filtration induced by crystalloid hemodilution. We hypothesized that increasing the colloid osmotic pressure of blood cardioplegia would stop fluid filtration into the cardiac interstitium, thus preventing myocardial oedema and cardiac dysfunction.

METHODS

We determined myocardial water content in six dogs by microgravimetry and myocardial lymph flow from the major prenodal cardiac lymphatic. Preload recruitable stroke work was derived from sonomicrometry and micromanometry. The dogs were subjected to normothermic cardiopulmonary bypass primed with 6% hetastarch and 1 h of normothermic continuous antegrade blood cardioplegia (4:1 blood:6% hetastarch colloid osmotic pressure 21 +/- 2 mmHg) delivered at 50 mmHg perfusion pressure.

RESULTS

We found that despite increased colloid osmotic pressure, a small but significant increase in myocardial water content still occurred during blood cardioplegia. As myocardial lymph flow virtually ceased during cardioplegia, myocardial microvascular filtration must have been present. However, increased myocardial lymph flow following cardioplegia resulted in complete oedema resolution associated with normal left ventricular performance post-cardiopulmonary bypass.

CONCLUSIONS

Our data show that the plegic myocardium is prone to oedema formation because of both relatively enhanced fluid filtration and lymph flow cessation. We conclude that increasing the colloid osmotic pressure of normothermic blood cardioplegia minimizes myocardial oedema, thus preventing post-cardiopulmonary bypass cardiac dysfunction.