Ventricular enlargement in poor-outcome schizophrenia

BACKGROUND

A subset of patients with schizophrenia, defined on the basis of longitudinal deficits in self-care, may show a classic ("Kraepelinian") degenerative course. An independent validator of the phenomenologically defined Kraepelinian subtype might be provided by a structural indicator of possible brain degeneration: ventricular size as measured by computed tomography (CT).

METHODS

To examine whether Kraepelinian patients would show a differential increase in ventricular size over time, two CT scans were conducted at intervals separated by > 4 years, an average of 5 years. Fifty-three male patients with DSM-III-R diagnoses of chronic schizophrenia were subdivided into Kraepelinian (n = 22; mean age = 42 +/- 6 years) and non-Kraepelinian (n = 31; mean age = 38 +/- 12.2 years) subgroups. Kraepelinian patients were defined on the basis of longitudinal criteria: > 5 years of complete dependence on others for life necessities and care, lack of employment, and sustained symptomatology. Thirteen normal elderly volunteers (mean age = 60 +/- 17.8) were also scanned at 4-year intervals. CT measurements were made by raters without knowledge of subgroup membership. A semiautomated computer program was used to trace the anterior horn, lateral ventricles, and temporal horns for each slice level on which they were clearly seen.

RESULTS

The ventricles showed a bilateral increase in size over the 4-year interval in the Kraepelinian subgroup, more marked in the left hemisphere than the right. By contrast, neither the non-Kraepelinian subgroup nor the normal volunteers showed significant CT changes from scan 1 to scan 2.

CONCLUSIONS

Thus, the longitudinal dysfunctions in self-care that characterize the Kraepelinian patients were associated with an independent indicator of brain abnormality.

Association of elevated alpha 1-antichymotrypsin with cognitive impairment in a prospective study of the very old

OBJECTIVE

The authors investigated the relationships between concentrations of two acute-phase proteins, alpha 1-antichymotrypsin (ACT) and alpha 2-macroglobulin (MAC), and cognitive impairment in the very old.

METHOD

Concentrations of ACT and MAC were determined in a prospective study using sera from medically stable elderly nursing home residents. Cognitive impairment was assessed with the Mini-Mental State.

RESULTS

Concentrations of ACT were associated with greater cognitive impairment, as reflected by lower Mini-Mental State scores. This relationship did not exist for MAC.

CONCLUSIONS

These data extend previous reports that patients with Alzheimer's disease have greater concentrations of ACT in their blood by demonstrating in a diagnostically diverse nursing home population a relationship between serum ACT and mental status. Elevated serum ACT in patients with compromised mental status may reflect a cerebral acute-phase response.

Experimental approaches to cognitive disturbance in Alzheimer's disease

This paper reviews available and potential treatments for the cognitive disturbances associated with Alzheimer's disease. The neurochemical, neuropathological, and molecular-biological abnormalities associated with this disorder, as well as possible sites for pharmacological intervention, are discussed. These sites include genetic alterations in apolipoprotein E, amyloid precursor protein, and presenilin. Additionally, modification of amyloid processing, tau processing, and calcium regulation may have a role in future treatment. Intriguing epidemiological findings involving antiinflammatories, antioxidants, and estrogen for the cognitive deficits associated with Alzheimer's disease suggest the need for clinical trials of these agents. The current status of cholinesterase inhibitors, muscarinic receptor agonists, nicotine, and adrenergic and glutaminergic approaches to treatment are described.

Beta-blockade as an alternative to cardioplegic arrest during cardiopulmonary bypass

BACKGROUND

As an alternative to cardioplegic arrest, cardiac surgical conditions have been produced using beta-blocker-induced minimal myocardial contraction (MMC) during cardiopulmonary bypass. The technique of MMC involves the use of high-dose intravenous esmolol to suppress myocardial chronotropy and inotropy sufficiently to produce cardiac surgical conditions. The purpose of this study was to compare conventional crystalloid cardioplegic arrest with MMC in terms of ischemia avoidance, myocardial edema formation, and cardiac function.

METHODS

Twelve dogs were placed on cardiopulmonary bypass. Six dogs were subjected to crystalloid cardioplegic arrest for 2 hours. Surgical conditions were produced in the other 6 dogs for 2 hours using intravenous esmolol without aortic clamping or cardioplegia. Arterial and coronary sinus lactate concentrations were determined as a gauge of myocardial ischemia. Myocardial water content was determined using microgravimetry and preload recruitable stroke work was determined using sonomicrometry and micromanometry.

RESULTS

Significant lactate washout was demonstrated after cardioplegic arrest but not after MMC. Myocardial water content was significantly less during and after MMC compared with cardioplegic arrest (p < 0.05). Preload recruitable stroke work was decreased compared with baseline values in both groups (p < 0.05).

CONCLUSIONS

In contrast to a previous study that involved 1 hour of MMC, in this study, ventricular function was decreased to the same extent as with cardioplegic arrest after 2 hours of MMC. This was attributed to the accumulation of ASL-8123, the primary metabolite of esmolol, which possesses beta-antagonist properties. Although postbypass ventricular function is similar in both groups, MMC appears to be superior in terms of ischemia avoidance and myocardial edema formation.

Alzheimer disease and related neurodegenerative diseases in elderly patients with schizophrenia: a postmortem neuropathologic study of 100 cases

BACKGROUND

Clinical studies suggest that severe cognitive impairment is common among elderly patients with schizophrenia who reside in long-stay psychiatric institutions; however, previous autopsy-based neuropathologic investigations have provided conflicting results about the occurrence of Alzheimer disease (AD) in elderly patients with schizophrenia. We report the results of a comprehensive neuropathologic study performed to identify AD and other dementing neurodegenerative diseases in elderly patients with schizophrenia.

METHODS

A neuropathologic examination was performed on 100 consecutive autopsy brain specimens of patients aged 52 to 101 years (mean, 76.5 years). A cognitive assessment of these cases was also done by employing the Clinical Dementia Rating Scale. For comparison, we included 47 patients with nonschizophrenic psychiatric disorders from the same psychiatric hospital and 50 age-matched control subjects.

RESULTS

Although 72% of the patients with schizophrenia showed cognitive impairment, AD was diagnosed in only 9% of the patients and other dementing diseases were diagnosed in only 4% of the patients. The degree of senile plaques or neurofibrillary tangles was not different in the group with schizophrenia compared with the age-matched controls or the group with nonschizophrenic psychiatric disorders. The higher Clinical Dementia Rating Scale scores lacked correlation with neuropathologic evidence of dementing disorders. In the 87 cases lacking a neuropathologic diagnosis of AD or other dementing disorders, the mean (+/-SD) Clinical Dementia Rating Scale score was 2.21 (+/-1.14), with 43 of the cases scoring 3 or higher (indicating severe, profound, or terminal cognitive impairment).

CONCLUSIONS

This study provides evidence that elderly patients with schizophrenia are not inordinately prone to the development of AD or to increased senile plaques or neurofibrillary tangle formation in the brain. Other dementing neurodegenerative disorders are also uncommon. The cognitive impairment in elderly patients with schizophrenia must, therefore, be related to some alternative mechanisms.

Human erythropoietin dimers with markedly enhanced in vivo activity

Human erythropoietin, a widely used and important therapeutic glycoprotein, has a relatively short plasma half-life due to clearance by glomerular filtration as well as by other mechanisms. We hypothesized that an erythropoietin species with a larger molecular size would exhibit an increased plasma half-life and, potentially, an enhanced biological activity. We now report the production of biologically active erythropoietin dimers and trimers by chemical crosslinking of the conventional monomeric form. We imparted free sulfhydryl residues to a pool of erythropoietin monomer by chemical modification. A second pool was reacted with another modifying reagent to yield monomer with maleimido groups. Upon mixing these two pools, covalently linked dimers and trimers were formed that were biologically active in vitro. The plasma half-life of erythropoietin dimers in rabbits was >24 h compared with 4 h for the monomers. Importantly, erythropoietin dimers were biologically active in vivo as shown by their ability to increase the hematocrits of mice when injected subcutaneously. In addition, the dimers exhibited >26-fold higher activity in vivo than did the monomers and were very effective after only one dose. Dimeric and other oligomeric forms of Epo may have an important role in therapy.

Lateral ventricular enlargement in schizophrenic probands and their siblings with schizophrenia-related disorders

BACKGROUND

To investigate possible genetic determinants of ventricular enlargement in schizophrenia, we compared lateral ventricle/brain ratios (VBRs) in schizophrenic patients with their own siblings, some with and some without other schizophrenia-related disorders [e.g., schizotypal personality disorder (SPD)], as well as with a group of unrelated normal controls.

METHODS

VBRs, measured by computed tomography, were compared in both groupwise and within-sibship analyses, the latter method providing a measure of control over familial/genetic factors related to VBR, but unrelated to schizophrenia.

RESULTS

The VBRs were significantly different across the groups, but the only significant pairwise group comparison was between the schizophrenia and no-SRD family member groups. In the within-sibship analyses, however, the VBRs of those with SPD and schizophrenia were similar, and both groups had significantly larger VBRs than their own siblings without SRD. In addition, siblings with a negative family history for SRD had larger VBRs than family history positive siblings.

CONCLUSIONS

The results suggest that specific schizophrenia-related genetic factors may help determine ventricular enlargement in familial schizophrenia. The larger VBRs in family history negative siblings might be attributable to genetic factors not specifically associated with schizophrenia, but which nevertheless increase its susceptibility.

Dopamine receptor transcript expression in striatum and prefrontal and occipital cortex. Focal abnormalities in orbitofrontal cortex in schizophrenia

BACKGROUND

The identification of novel subtypes of the dopamine receptors has renewed interest in the involvement of dopaminergic mechanisms in schizophrenia. We determined the expression of transcripts encoding the dopamine receptors in the brains of schizophrenic patients.

METHODS

The levels of the messenger RNA molecules encoding the 5 dopamine receptors were quantified in postmortem brain samples from 16 schizophrenic patients and 9 control subjects. Samples from multiple regions of the prefrontal cortex, primary visual cortex, and striatum were subjected to in situ hybridization followed by quantitative image analysis.

RESULTS

Expression of dopamine receptor transcripts did not differ between schizophrenic patients and controls in striatum or visual cortex. Dramatic decreases of dopamine receptor transcripts were found in the prefrontal cortex, but these changes were restricted to the D3 and D4 receptors, and localized to Brodmann area 11 (orbitofrontal cortex).

CONCLUSIONS

Cortical dopaminergic neurotransmission may be disrupted in schizophrenia at the level of receptor expression. There appears to be a focal abnormality of D3 and D4 messenger RNA expression in the prefrontal cortex, with down-regulation of both, consistent with prefrontal cortical hypodopaminergia in schizophrenia.

Augmenting cardiac contractility hastens myocardial edema resolution after cardiopulmonary bypass and cardioplegic arrest

Although myocardial edema is associated with cardiopulmonary bypass (CPB) and cardioplegic arrest (CPA), interventions to expedite edema removal have not been investigated. The primary mechanism for the removal of excess interstitial fluid in the heart is myocardial lymphatic drainage, but lymphatic function can be impaired by decreased contractility because of edema. The purpose of this study was to determine whether enhancing cardiac contractility would increase myocardial lymphatic function and hasten edema resolution after CPB. Sixteen dogs were subjected to CPB and 1 h of hypothermic CPA. After weaning from CPB, 10 dogs received an intravenous dobutamine infusion and 6 dogs received no inotropic support. We determined myocardial lymph driving pressure from the major cardiac lymphatic, myocardial water content by using microgravimetry, and the peak rate of left ventricular pressure increase (dP/dmax) by using micromanometry. Measurements were taken at baseline, during CPA, and 60 min after CPB. Compared with controls, dobutamine-treated dogs had an increased dP/dmax (P < 0.05), which was associated with higher lymph driving pressures (P < 0.05), resulting in lower myocardial water gain 1 h after CPB (P < 0.05). We conclude that the resolution of myocardial edema after CPB was hastened by dobutamine. Organized ventricular contraction and myocardial contractility seem to be important determinants of myocardial lymphatic function and myocardial edema removal. These findings suggest that the administration of inotropic drugs after CPB may hasten cardiac recovery.

IMPLICATIONS

Myocardial edema, which develops during cardiopulmonary bypass and cardioplegic arrest, contributes to cardiac dysfunction after heart surgery. This study demonstrated that enhancement of cardiac contractility by the administration of dobutamine after cardiopulmonary bypass and cardioplegic arrest was associated with increased myocardial lymphatic function and hastened edema resolution in dogs.

Noncognitive disturbances in Alzheimer's disease: frequency, longitudinal course, and relationship to cognitive symptoms

OBJECTIVE

To investigate the frequency and longitudinal course of symptoms of depression, agitation, and psychosis in a longitudinally studied sample of patients with Alzheimer's disease (AD).

DESIGN

Longitudinal study of AD patients with follow-up assessments at 6-month intervals for an average of more than 3 years.

SETTING

Alzheimer's Disease Research Center of the Mount Sinai Medical Center and the Bronx VA Medical Center, New York.

PARTICIPANTS

A total of 153 AD patients.

MEASUREMENTS

Blessed Test of Information, Memory and Concentration (BIMC) and the Alzheimer's Disease Assessment Scale cognitive (ADAS-Cog) and noncognitive (ADAS-NC) subscales.

RESULTS

At entry into the study, more than 90% of patients had a behavioral disturbance that was rated as mild or worse on one of the 10 ADAS noncognitive items; and 40% had at least one rating that was moderate or severe. Correlational analyses indicated that, with the exception of the two mood-related items, noncognitive symptoms on the ADAS were not highly correlated with one another. Only one of the noncognitive items, concentration, was strongly correlated with the severity of cognitive impairment. On average, patients showed progressively worse cognitive functioning over time as measured both by the ADAS-Cog and the BIMC. The mean severity of noncognitive symptoms did not change during the course of a 5-year follow up. The severity of behavioral disturbance at any one evaluation was negatively correlated with change in behavior during the next 6 months and was not correlated with cognitive decline.

CONCLUSION

Mild behavioral disturbances are common, whereas moderate to severe behavioral symptoms are less frequent in this population of AD patients. Disturbances in mood and manifestations of agitation and psychotic symptoms are not closely related to one another and show little progressive worsening over time. Rather, they tend to be episodic such that increasing severity at one time is usually followed by improvement later. Concentration problems are a manifestation of cognitive dysfunction rather than behavioral disturbance in AD. Implications of these results for treatment of noncognitive disturbances in AD are discussed.

The Caregiver Activity Survey (CAS): development and validation of a new measure for caregivers of persons with Alzheimer's disease

BACKGROUND

Most instruments that measure the impairments associated with Alzheimer's disease assess symptom severity. Little attention has been paid to the illness's impact on the time formal and informal caregivers spend caring for Alzheimer's individuals. A tool that measures the time spent caregiving would help to determine the economic impact of the illness. The Caregiver Activity Survey (CAS) was developed to measure the time caregivers spend aiding Alzheimer's patients with their day-to-day activities.

METHODS

The test-retest reliability of the CAS was assessed during a 3-week study with 42 Alzheimer's patients and their caregivers. The CAS was validated with the Alzheimer's Disease Assessment Scale Cognitive Subscale (ADAS-Cog), the Mini Mental State Exam (MMSE) and the Physical Self Maintenance Scale (PSMS).

RESULTS

The final version of the CAS consists of six items (communicating with the person, using transportation, eating, dressing, looking after one's appearance and supervising the person). The six-item CAS total score has high test-retest reliability, with ICC = 0.88 between weeks 1 and 3. The scale has strong convergent validity with the ADAS-Cog (r = 0.61), MMSE (r = -0.57) and PSMS (r = 0.43). Efforts to include a dimension that reflects caregiver burden were not successful, in part due to the reluctance of caregivers to acknowledge that caregiving is bothersome.

CONCLUSIONS

The CAS provides a new tool that measures time spent caring for Alzheimer's individuals. The instrument may be used to augment existing clinical assessments that measure the efficacy of potentially therapeutic agents for persons with Alzheimer's disease.

Cooling gradients and formation of gaseous microemboli with cardiopulmonary bypass: an echocardiographic study

BACKGROUND

Previous studies demonstrated gas emboli formation during rewarming from hypothermia on cardiopulmonary bypass when the temperature gradient exceeded a critical threshold. It also has been suggested that formation of arterial gas emboli may occur during cooling on cardiopulmonary bypass when cooled oxygenated blood exiting the heat exchanger is warmed on mixture with the patient's blood. The purpose of this study was to determine under what circumstances gas emboli formation would occur during cooling on cardio-pulmonary bypass.

METHODS

Eight anesthetized mongreal dogs were placed on cardiopulmonary bypass using a roller pump, membrane oxygenator, and arterial line filter. For emboli detection, we positioned a transesophageal echocardiographic probe at the aortic arch distal to the aortic cannula and Doppler probes at the common carotid artery and the arterial line. Cooling gradients between normothermic blood and cooled arterial perfusate of 5 degrees, 10 degrees, 15 degrees, 20 degrees, and 0 degree C (isothermal controls) were investigated. In addition to preestablished temperature gradients, we investigated the effect of rapid cooling (maximal flow through the heat exchanger at a water bath temperature of 4 degrees C) after the initiation of normothermic cardiopulmonary bypass.

RESULTS

Minimal gas emboli were detected at the aortic arch at gradients of 10 degrees C or greater. The incidence of emboli was related directly to the magnitude of the temperature gradient (p < 0.01). No emboli were detected at the carotid artery. During rapid cooling, no emboli were observed either at the aorta or at the carotid artery.

CONCLUSIONS

Cooling gradients of 10 degrees C or greater may be associated with gas emboli formation, but they may be of limited clinical significance because no emboli were detected distal to the aortic arch. During the application of rapid cooling, no emboli formation was observed.

Pharmacological modulation of Alzheimer's beta-amyloid precursor protein levels in the CSF of rats with forebrain cholinergic system lesions

Abnormal deposition and accumulation of Alzheimer's amyloid beta-protein (A beta) and degeneration of forebrain cholinergic neurons are among the principal features of Alzheimer's disease. Studies in rat model systems have shown that forebrain cholinergic deficits are accompanied by induction of cortical beta-amyloid precursor protein (beta-APP) mRNAs and increased levels of secreted beta-APP in the CSF. The studies reported here determined whether the CSF levels of secreted beta-APP could be altered pharmacologically. In different experiments, rats with lesions of the forebrain cholinergic system received injections of vehicle, a muscarinic receptor antagonist scopolamine, or one of two cholinesterase inhibitors - diisopropyl phosphorofluoridate (DFP) or phenserine. Scopolamine was administered to determine whether the levels of beta-APP in the CSF could be increased by anticholinergic agents. The cholinesterase inhibitors were administered to determine whether the forebrain cholinergic system lesion-induced increases in CSF beta-APP could be reduced by cholinergic augmentation. Scopolamine administration led to a significant increase in the CSF levels of secreted beta-APP in sham-lesioned rats. Phenserine, a novel, reversible acetyl-selective cholinesterase inhibitor, significantly decreased the levels of secreted beta-APP in the CSF of forebrain cholinergic system-lesioned rats whereas DFP, a relatively non-specific cholinesterase inhibitor, failed to affect CSF levels of secreted beta-APP. These results suggest that the levels of secreted beta-APP in the CSF can be pharmacologically modulated but that this modulation is dependent upon the status of the forebrain cholinergic system and the pharmacological properties of the drugs used to influence it.

Increased concentrations of presynaptic proteins in the cingulate cortex of subjects with schizophrenia

BACKGROUND

Cytoarchitectural and neurochemical studies demonstrate disorganization in the cerebral cortex in schizophrenia, which perhaps underlies the severe behavioral disturbances of the disease. This neuronal disarray should be accompanied by synaptic abnormalities. As such, presynaptic proteins have proved valuable indexes of synaptic density and their concentrations have correlated markedly with synaptic loss. Our study sought to determine whether abnormalities exist in the concentrations of presynaptic proteins in the postmortem cerebral cortex of subjects with schizophrenia.

METHODS

Presynaptic protein immunoreactivities were assessed in 4 different cerebrocortical regions derived from 16 elderly controls, 19 elderly subjects with schizophrenia, and 24 subjects with Alzheimer's disease. Tissues were assayed with the monoclonal antibodies EP10 and SP4, which recognize synaptophysin, and the monoclonal antibodies SP6 and SP14, which detect syntaxin and synaptosomal-associated protein-25-kd immunoreactivities, respectively.

RESULTS

In subjects with schizophrenia relative to controls, presynaptic proteins were increased in the cingulate cortex, but were unchanged in the temporal, frontal, and parietal cortices. In contrast, when cases with Alzheimer's disease were compared with controls, presynaptic proteins were decreased in the frontal, temporal, and parietal samples.

CONCLUSIONS

These findings reveal changes in the synaptic organization of the cingulate cortex in schizophrenia relative to other areas examined. These changes are distinct from the deficits in presynaptic proteins observed in Alzheimer's disease.

The search for disease-modifying treatment for Alzheimer's disease

As a result of advances in the understanding of neurodegenerative mechanism in Alzheimer's disease, several strategies for the development of disease-modifying treatment are being investigated. Nerve growth factor and other neurotrophins may improve neuronal survival, although targeted delivery remains an obstacle. Modulation of protein processing has the potential to decrease the formation of plaques and tangles. Pharmacologic reduction of oxidative stress and destructive inflammation may slow the rate of neurodegeneration. Continued research into basic mechanisms, along with therapeutic trials of promising drugs, are improving the likelihood that it will soon be possible to slow the progression of this disease.

The validity of the family history method for identifying Alzheimer disease

OBJECTIVE

To examine the validity of the family history method for identifying Alzheimer disease (AD) by comparing family history and neuropathological diagnoses.

METHODS

Seventy-seven former residents of the Jewish Home and Hospital for the Aged, New York, NY, with neuropathological evaluations on record were blindly assessed for the presence of dementia and, if present, the type of dementia through family informants by telephone interviews. The Alzheimer's Disease Risk Questionnaire was used to collect demographic information and screen for possible dementia. If dementia was suspected, the Dementia Questionnaire was administered to assess the course and type of dementia, i.e., primary progressive dementia (PPD, likely AD), multiple infarct dementia, mixed dementia (i.e., PPD and multiple infarct dementia), and other dementias based on the modified Diagnostic and Statistical Manual of Mental Disorders, Third Edition, criteria.

RESULTS

Sixty (77.9%) of 77 elderly subjects were classified as having dementia and 17 (22.1%) were without dementia by family history evaluation. Of the 60 elderly subjects with dementia, 57 (95%) were found at autopsy to have had neuropathological changes related to dementia. The sensitivity of the family history diagnosis for dementia with related neuropathological change was 0.84 (57 of 68) and the specificity was 0.67 (6 of 9). Using family history information to differentiate the type of dementia, the sensitivity for definite or probable AD (with or without another condition) was 0.69 (36 of 51) and the specificity was 0.73 (19 of 26). The majority (9 of 15) of patients testing false negative for PPD had a history of stroke associated with onset of memory changes, excluding a diagnosis of PPD.

CONCLUSIONS

Identifying dementia, in general, and AD, in particular, has an acceptable sensitivity and specificity. As is true for direct clinical diagnosis, the major issue associated with misclassifying AD in a family history assessment is the masking effects of a coexisting non-AD dementia or dementia-related disorders, such as stroke. Including mixed cases, ie, PPD and multiple infarct dementia in estimates of the familial risk for AD can reduce the extent of underestimation of PPD.

Validity of the family history method for identifying schizophrenia-related disorders

We examined the family history method's validity for identifying schizophrenia related disorders (SRD) by comparing family history and family study derived diagnoses. First degree relatives (n = 284) of 48 psychiatrically disordered probands, predominantly with schizophrenia, were diagnosed using the Family History RDC (FH-RDC) which include three psychotic schizophrenia related disorders (P-SRD): schizophrenia, chronic SAD and chronic unspecified functional psychosis (CUFP). Supplementary criteria for schizophrenia related personality disorders (SRP), derived to identify schizotypal and paranoid personality disorders (PD), were also assessed. About two thirds of these relatives (n = 196; 69.0%) were independently diagnosed by RDC and DSM-III-R on both axis I and axis II in a family study. The specificity was 1.0 (178/178) and the sensitivity of the family history derived diagnosis for P-SRD was 0.72 (13/18). Sensitivity for P-SRD was improved, however, by inclusion of SRP which captured three of the five false negative relatives. The sensitivity of SRP for schizotypal or paranoid PD was 0.39 (15/38) and the specificity was 0.92 (127/138). The FH-RDC have moderately good sensitivity and excellent specificity for the psychotic schizophrenia related disorders. While family history criteria for SRP are not a good proxy for schizotypal or paranoid PD, they can enhance the family history method's sensitivity for SRD.

Effect of body repositioning after venous air embolism. An echocardiographic study

BACKGROUND

Current therapy for massive venous air embolism (VAE) may include the use of the left lateral recumbent (LLR) position, although its effectiveness has been questioned. This study used transesophageal echocardiography to evaluate the effect of body repositioning on intracardiac air and acute cardiac dimension changes.

METHODS

Eighteen anesthetized dogs in the supine position received a venous air injection of 2.5 ml/kg at a rate of 5 ml/ s. After 1 min the dogs were repositioned into either the LLR, LLR 10 degrees head down (LLR-10 degrees), right lateral recumbence, or remained in the supine position.

RESULTS

Repositioning after VAE resulted in relocation of intracardiac air to nondependent areas of the right heart. Peak right ventricular (RV) diameter increase and mean arterial pressure decrease were greater in the repositioned animals compared with those in the supine position (P < 0.05). Right ventricular diameter and mean arterial pressure showed an inverse correlation (r = 0.81). Peak left atrial diameter decrease was greater in the LLR and LLR-10 degrees positions compared with the supine position (P < 0.05). Repositioning did not influence peak pulmonary artery pressure increase, and no correlation was found between RV diameter and pulmonary artery pressure. All animals showed electrocardiogram and echocardiographic changes reconcilable with myocardial ischemia.

CONCLUSIONS

In dogs, body repositioning after VAE provided no benefit in hemodynamic performance or cardiac dimension changes, although relocation of intracardiac air was demonstrated. Right ventricular air did not appear to result in significant RV outflow obstruction, as pulmonary artery pressure increased uniformly in all groups and was not influenced by the relocation of intracardiac air. The combination of increased RV afterload and arterial hypotension, possibly with subsequent RV ischemia rather than RV outflow obstruction by an airlock appeared to be the primary mechanism for cardiac dysfunction after VAE.

Age-related differences in formal thought disorder in chronically hospitalized schizophrenic patients: a cross-sectional study across nine decades

OBJECTIVE

This study used a cross-sectional design to examine the frequency of occurrence and severity of 10 different signs of thought disorder in schizophrenic patients across the lifespan.

METHOD

Schizophrenic patients, who ranged in age from 19 to 96 years (N = 392), were examined with the Scale for Assessment of Thought, Language, and Communication. The cognitive functioning of the geriatric patients (patients over the age of 64, N = 120) was also assessed.

RESULTS

Poverty of speech was more common and more severe in geriatric patients, while four different signs of thought disorder that reflect disconnected speech were less common and less severe in geriatric patients. Analysis of covariance found that the lower severity of disconnection thought disorders in the older patients was not attributable to differences in the amount of speech produced.

CONCLUSIONS

Aspects of disconnected speech were less severe in older patients, while the severity and frequency of poverty of speech were greater. These findings suggest that the two previously identified separate dimensions of communication disorder in schizophrenia vary differently with age and possibly in their cognitive and biological underpinnings.

Eye tracking, attention, and schizotypal symptoms in nonpsychotic relatives of patients with schizophrenia

BACKGROUND

Biological relatives of patients with schizophrenia demonstrate an increased prevalence of schizotypal personality disorder symptoms, eye tracking deficits, and attentional disturbances. We investigated whether these hypothesized components of a schizophrenia-related phenotype are associated with one another or are independent in nonpsychotic relatives of patients with schizophrenia.

METHODS

Eighty-three nonpsychotic first-degree relatives of 38 patients with schizophrenia and 45 control subjects without a psychiatric diagnosis underwent clinical evaluation, eye tracking evaluation, and the Continuous Performance Test (CPT) of visual attention.

RESULTS

Eye tracking qualitative rating was more powerful than quantitative eye tracking measures or CPT measures in discriminating relatives of patients with schizophrenia from control subjects. Correlations between neurocognitive variables and DSM-III-R schizotypal personality disorder symptom clusters suggested that CPT errors of omission are associated with positive schizotypal symptoms. Eye tracking measures were not significantly correlated with schizotypal symptoms or CPT errors in relatives of patients with schizophrenia.

CONCLUSIONS

Eye tracking deficits in the relatives of patients with schizophrenia are unrelated to CPT deficits and schizotypal symptoms. Eye tracking deficits and disturbances in visual attention may be separate components of a schizophrenia-related phenotype and should be considered as independent factors in genetic studies of schizophrenia.

A risk-benefit assessment of tacrine in the treatment of Alzheimer's disease

Tacrine, the first drug specifically approved for Alzheimer's disease, produces symptomatic improvement. The theoretical rationale behind treating Alzheimer's disease with tacrine is based on central cholinergic depletion. Tacrine is centrally acting, uncompetitive reversible inhibitor of acetylcholinesterase and butyrylcholinesterase. Multiple clinical trials support the effectiveness of tacrine in Alzheimer's disease. High dosages of tacrine are required for efficacy, with the potential for hepatic and mild gastrointestinal adverse effects. However, the benefits of tacrine currently outweigh its risks, and a trial of the drug should be offered to patients. As clinical experience with tacrine increases, the long term risk-benefit equation may be refined.

Regulation of microvascular filtration in the myocardium by interstitial fluid pressure

We hypothesized that myocardial microvascular filtration rate (Jv) could be manipulated by varying end-diastolic myocardial interstitial hydrostatic (P(int)) pressure. Dogs under general anesthesia were instrumented with intramyocardial capsules to measure P(int) and with prenodal myocardial lymphatic trunk cannulas and superior vena caval balloon-tipped catheters to manipulate myocardial lymph flow. Because, for a given surface area, the lymph-to-plasma protein concentration ration (CL/CP) varies inversely with JV, CL/CP was utilized as an index of changes in JV. When lymphatic outflow pressure (P0) was elevated to abolish lymph flow and force myocardial interstitial fluid volume to expand, P(int) rose significantly from 15.0 +/- 0.8 to 27.6 +/- 1.0 mmHg and CL/CP increased significantly from 0.75 +/- 0.04 to 0.85 +/- 0.04, indicating a decrease in JV. When P0 was lowered and lymph flow resumed, P(int) and CL/CP decreased significantly to 15.3 +/- 0.9 mmHg and 0.75 +/- 0.04, respectively, indicating an increase in JV. We conclude that myocardial microvascular filtration rate may be modulated by changes in P(int) resulting from alterations in myocardial interstitial fluid volume secondary to variations in lymph flow from the heart.

Myocardial fluid balance in acute hypertension

OBJECTIVES

We hypothesized that (1) acute arterial hypertension increases myocardial microvascular fluid filtration and (2) the combination of acute arterial hypertension and coronary sinus pressure elevation may increase myocardial microvascular filtration sufficiently to estimate the osmotic reflection coefficient of the myocardial exchange vessels.

METHODS

In nine mechanically ventilated dogs we cannulated the prenodal major cardiac lymph trunk. With the use of central venous phenylephrine infusion, mean arterial pressure (MAP) was raised progressively to 120, 160, and 180 mm Hg. In five dogs we additionally raised coronary sinus pressure (CSP) to 20 and 40 mm Hg. At each manipulation of MAP and/or CSP, we measured indexes of myocardial lymphatic function and lymph-to-plasma concentration ratios for total protein (CL(TP)/CP(TP) and albumin (CL(alb)/CP(alb)).

RESULTS

Myocardial lymph flow rate (QL; microL/min) increased exponentially (QL = 10.9.e0.014.(MAP) and myocardial lymph driving pressure (PL; mm Hg) increased linearly (PL = 2.30 + 0.20 + 0.20 . MAP) following increases, whereas CL(TP)/CP(TP) and CL(alb)/CP(alb) decreases from 0.67 +/- 0.07 (SD) to 0.56 +/- 0.10 and from 0.91 +/- 0.05 to 0.75 +/- 0.11, respectively. Adding CSP elevation increased QL up to 12 times control associated with further CL(TP)/C(TP) and CL(alb)/CP(alb) decreases to 0.49 +/- 0.05 and 0.59 +/- 0.02, respectively.

CONCLUSIONS

We conclude that hypertensive arterial pressures are, at least in part, transmitted to the myocardial microvascular exchange vessels in the intact animal leading to increased microvascular fluid filtration. However, the combination of acute arterial hypertension and coronary sinus pressure elevation is not sufficient to produce filtration independence required for myocardial osmotic reflection coefficient determination.

Protein kinase C-epsilon is necessary for erythropoietin's up-regulation of c-myc and for factor-dependent DNA synthesis. Evidence for discrete signals for growth and differentiation

Erythropoietin regulates the transcription of the protooncogenes c-myc and c-myb by discrete protein kinase C (PKC)-dependent and protein serine/threonine phosphatase-dependent pathways, respectively (Spangler, R., Bailey, S. C., and Sytkowski, A. J. (1991) J. Biol. Chem. 266, 681-684; Patel H. R, Choi H.-S, and Sytkowski A. J. (1992) J. Biol. Chem. 267, 21300-21302). In the present study we demonstrate that up-regulation of c-myc requires the PKC-epsilon isoform and that this pathway is required for erythropoietin-induced DNA synthesis (growth) but apparently not for beta-globin expression (differentiation). Treatment of Rauscher murine erythroleukemia cells resulted in phosphorylation of phospholipase C-gamma1 and activation of PKC-epsilon as evidenced by its translocation from soluble to particulate subcellular fractions. Artificial down-regulation of PKC-epsilon with antisense oligodeoxynucleotides blocked erythropoietin's up-regulation of c-myc in a concentration-dependent manner. In contrast, antisense oligodeoxynucleotides to PKC-alpha, -beta, -gamma, -delta, and -zeta had no effect. Although down-regulation of PKC-epsilon blocked the increase in c-myc expression, it did not inhibit erythropoietin induction of beta-globin expression, a marker of erythroid differentiation. However, down-regulation of PKC-epsilon did block factor-dependent DNA synthesis quantified by measurement of [3H]thymidine incorporation into newly synthesized DNA of normal murine erythroid cells. The results are consistent with discrete intracellular signals regulating erythroid cell growth and differentiation.

Empirical evaluation of the factorial structure of clinical symptoms in schizophrenia: effects of typical neuroleptics on the brief psychiatric rating scale

There has been little investigation of the effect of neuroleptic medication on the structure of symptoms in schizophrenia. In this study, 135 male schizophrenic patients were rated with the Brief Psychiatric Rating Scale (BPRS) after 4 weeks of treatment with typical neuroleptic medication and after 2 weeks free of neuroleptics, with the order of assessment varying across patients. Confirmatory factor analyses (CFA) found that there were no differences in symptom structure across medication status and no differences in the structure of symptoms in treatment responders and nonresponders. The typical 5-factor BPRS model fit the data poorly and the fit improved considerably through deletion of items measuring symptoms not associated with schizophrenia, suggesting that some of the symptoms that contribute to a total BPRS score may be adding primarily error variance. Although the sample size in this study is limited, the results suggest that using total BPRS scores to measure severity of schizophrenic symptoms should be reconsidered.

Functional and structural role of arginine 103 in human erythropoietin

The identification of amino acid residues essential for function of the hematopoietic growth factor erythropoietin has been approached by several methods, including comparisons of related sequences, immunochemical approaches, mutagenesis, and computer modeling. We have reported previously that mutations within amino acids 100-109 of erythropoietin can have profound effects on the hormone's structure and/or activity and that Arg103 is especially important for function [Y. Chern, T. Chung, and A. J. Sytkowski (1991) Eur. J. Biochem. 202, 225-229; J. Grodberg, K.L. Davis, and A. J. Sytkowski (1993) Eur. J. Biochem. 218, 597-601]. We have now constructed a series of Arg103 substitutions in order to determine the structural features of amino acid 103 required for biological activity. Each of the mutants was expressed and secreted efficiently by transfected COS1 cells. Mutants Arg103Asn, Arg103Gln, and Arg103Glu exhibited no biological activity. In contrast, Arg103His and Arg103Lys had specific activities equal to 2 and 25%, respectively, of that of wild-type erythropoietin, indicating that a positive charge may be required at position 103 but that other constraints necessitate the presence of Arg for full activity. A role for amino acid 103 in the protein's structure was supported by the results of experiments which revealed marked differences in heat stability among the mutants. We hypothesize that an Arg at position 103 may confer sufficient flexibility to the receptor binding domain to facilitate initial binding to the receptor and may then stabilize the binary complex by hydrogen bonding with carbonyls of the receptor protein.

A pilot study of prednisone in Alzheimer's disease

Preliminary to a multicenter trial, an open-label study was conducted of prednisone treatment in Alzheimer's disease. Prednisone was given at an initial dose of 10 mg (part 1) or 20 mg (part 2) and tapered over 7 weeks. There were no serious adverse events attributed to the medication, and there were no significant changes in either mean cognitive or behavioral assessment scores with treatment during either part. Serum levels of the acute phase proteins alpha-1-antichymotrypsin and C-reactive protein did not change significantly during part 1, but were suppressed by the higher dose given in part 2. Thus, a prednisone regimen with an initial dose of 20 mg is tolerable and results in suppression of the acute phase response in Alzheimer's disease.

Cardiac surgical conditions induced by beta-blockade: effect on myocardial fluid balance

BACKGROUND

Both crystalloid and blood cardioplegia result in cardiac dysfunction associated with myocardial edema. This edema is partially due to the lack of myocardial contraction during cardioplegia, which stops myocardial lymph flow. As an alternative, acceptable surgical conditions have been created in patients undergoing coronary artery bypass operations with esmolol-induced minimal myocardial contraction. We hypothesized that minimal myocardial contraction during circulatory support using either standard cardiopulmonary bypass (CPB) or a biventricular assist device would prevent myocardial edema by maintaining cardiac lymphatic function and thus prevent cardiac dysfunction.

METHODS

We placed 6 dogs on CPB and 6 dogs on a biventricular assist device and serially measured myocardial lymph flow rate and myocardial water content in both groups and preload recruitable stroke work only in the CPB dogs. In all dogs we minimized heart rate with esmolol for 1 hour during total circulatory support.

RESULTS

Although myocardial lymph flow remained at baseline level during CPB and increased during biventricular assistance, myocardial water accumulation still occurred during circulatory support. However, as edema resolved rapidly after separation from circulatory support, myocardial water content was only slightly increased after CPB and biventricular assistance, and preload recruitable stroke work was normal.

CONCLUSIONS

Our data suggest that minimal myocardial contraction during both CPB and biventricular assistance supports myocardial lymphatic function, resulting in minimal myocardial edema formation associated with normal left ventricular performance after circulatory support. The concept of minimal myocardial contraction may be a useful alternative for myocardial protection, especially in high-risk patients with compromised left ventricular function.

Ventricular enlargement associated with linkage marker for schizophrenia-related disorders in one pedigree

We previously obtained evidence indicating a genetic linkage marker for schizophrenia and related disorders (two-point lod score = 3.72, P = 0.01) on the short arm of chromosome 5(5p14.1-13.1) in one large pedigree. Automated computer algorithms were used to edge the brain and measure the volume of the ventricles, regional sulcal atrophy, and skull size and shape in the original nuclear family members. Of the 11 subjects who underwent computed tomography, six (three schizophrenic, two with schizotypal personality disorder, and one unaffected) carried the marker allele that co-segregated with schizophrenia-related disorders, while five (all unaffected) did not. The family members with the marker allele linked to schizophrenia-related disorders (n = 6) had significantly (P < 0.05) larger ventricle-brain ratios (VBRs) and more fronto-parietal atrophy (controlling for age) than the family members lacking the schizophrenia-related marker allele (n = 5). The three individuals with the largest VBRs all carried the marker, although they received diagnoses of no schizophrenia-related disorder, schizotypal personality disorder, and schizophrenia. Regional cortical values indicative of cerebrospinal fluid content were higher in the frontal and parietal regions of family members carrying the marker. The hypothesis that genetic linkage is associated with structural brain pathology is difficult to test because of all the potential compounding factors. Our findings suggest the possibility that, in this family, relatively enlarged VBR and fronto-parietal atrophy, as determined by computed tomograph, may be associated with a schizophrenia-related gene and present susceptibility to schizophrenia-related disorders. In addition to a replication of these findings in other similarly linked families yet to be identified, further studies using higher resolution structural and functional neuroimaging techniques will be required.

Computer-administration of questionnaires: a health screening system (HSS) developed for veterans

The introduction of microcomputers in psychological research has spawned a burgeoning number of tests of psychological or behavioral function, but few computerized systems for administering questionnaires have been developed. A Health Screening System (HSS) is described that combines the benefits of the paper-and-pencil format (e.g., convenient navigation within test questions) and the added benefits of computer-implementation (e.g., efficiency, automated scoring). The HSS features; a) appealing test appearance (e.g., text in large-size fonts, color backgrounds); b) clear wording of tests and instructions (identical wording as original tests except when clarity is served by changes); c) limiting need for Examiner-Subject interaction (e.g., continuously available on-line training, navigation within test questions, answer review capability, durable 9-button response unit); d) options (e.g., question skipping, spoken instructions, test questions, and answers on command); e) modification capabilities (e.g., color, text, test layout editing, control of test order, automated breaks, addition of tests to system); and f) extras (e.g., kernel of main instruction on each test screen, digitized video, audio message from Examiner in training, copyright notification on each screen, raw and summary data outputs in spreadsheet formal). Ten HSS tests were administered to 22 US military veterans, who took slightly longer to complete them than did 10 veterans who were administered the same tests in their original paper-and-pencil format. User reaction to the computerized HSS was positive.

Dopamine receptor mRNA expression in human striatum and neocortex

The distributions of the transcripts encoding the five dopamine receptors have been determined in the human striatum and selected regions of the neocortex. In the striatum significant levels of dopamine receptor expression are restricted to the D1, D2, and D3 receptors. D1 and D2 receptor messenger ribonucleic acids (mRNAs) are homogeneously distributed throughout the caudate, putamen, and nucleus accumbens. D3 receptor mRNA is particularly enriched in the nucleus accumbens, with moderate levels in the ventral putamen. In the prefrontal cortex D1 and D4 receptor mRNAs are the most abundant, although the other three transcripts are seen at lower levels. A similar pattern is seen in the temporal neocortex. In the occipital cortex, D1 receptor mRNA is the most abundant, D3 the rarest, while the other three transcripts are present at modest levels of expression. These data add to a growing understanding of the neuroanatomical distribution of these transcripts in the human brain. They are essential to understand in the context of the limbic circuitry of the brain, as new hypotheses of dysfunction of dopaminergic neurotransmission are advanced in psychiatry and as these receptor subtypes are targeted for development of novel pharmacological treatments.

Clinical characteristics of Kraepelinian schizophrenia: replication and extension of previous findings

OBJECTIVE

Subtypologies of schizophrenia based on cross-sectional criteria, such as the nomenclature of the DSMs, have not been successful in identifying valid diagnostic subgroups among patients with schizophrenia. A subtypology that uses criteria to classify individuals on the basis of longitudinal deficits in self-care may identify a more valid subgroup of schizophrenic patients.

METHOD

This study describes the clinical characteristics of a group of schizophrenic patients identified on the basis of a longitudinal criterion: at least 5 years of continuous and complete dependence on others for obtaining and maintaining the basic necessities of life, including food, clothing, and shelter.

RESULTS

Sixty-one "Kraepelinian" schizophrenic inpatients, when compared to 80 non-Kraepelinian schizophrenic inpatients who were similar in years of illness, age, and education, demonstrated more severe negative symptoms and more severe formal thought disorder; yet the severity of their delusions, hallucinations, and bizarre behavior did not differ significantly. None of the Kraepelinian patients and eight non-Kraepelinian patients met DSM-III-R criteria for schizoaffective disorder.

CONCLUSIONS

Data from this replication study suggest that Kraepelinian schizophrenic patients, identified on the basis of a longitudinal course characterized by severe dysfunctions in self-care, may represent an alternative, and possibly more valid, method of subtyping schizophrenia.

Evidence of a locus for schizophrenia and related disorders on the short arm of chromosome 5 in a large pedigree

We attempted to identify a locus for schizophrenia and related disorders in 24 nuclear families of schizophrenic probands using a predefined classification system for affected cases that included those disorders most clearly identified as sharing a genetic relationship with schizophrenia--schizoaffective disorder and schizotypal personality disorder. Initially, we evaluated 8 markers on chromosome 5 on the first 12 families with available genotyping and diagnostic assessments and, assuming autosomal dominant transmission, found a lod score of 2.67 for the D5S111 locus (5p14.1-13.1) in one large nuclear family (no. 17; sibship: n = 12; schizophrenia: n = 3; schizotypal personality disorder: n = 2); the other 11 families were much smaller, less complete, and provided little additional information. Other branches of no. 17 were then assessed and the 2-point lod score for family 17 rose to 3.72; using multipoint analysis the lod score in 17 was 4.37. When only schizophrenia was used to define affectedness, the positive evidence for linkage to D5S111 was greatly reduced. Sensitivity analysis indicated that the lod score is heavily dependent upon the predefined diagnostic criteria. Our studies of other families of schizophrenic probands eventually totalled 23, but linkage to D5S111 in these yielded a -2.41 lod score. The results provide evidence for genetic linkage of the D5S111 locus to schizophrenia and related disorders in one family. It may be of interest that over several generations, almost all the ancestors of family 17 could be traced back to a small, relatively isolated, hill region of Puerto Rico.

Neuropeptide deficits in schizophrenia vs. Alzheimer's disease cerebral cortex

Neuropeptide concentrations were determined in the postmortem cerebral cortex from 19 cognitive-impaired schizophrenics, 4 normal elderly subjects, 4 multi-infarct dementia (MID) cases, and 13 Alzheimer's disease (AD) patients. Only AD patients met criteria for AD. The normal elderly and MID cases were combined into one control group. Somatostatin concentrations were reduced in both schizophrenia and AD. Neuropeptide Y concentrations were reduced only in schizophrenia, and corticotropin-releasing hormone concentrations were primarily reduced in AD. Concentrations of vasoactive intestinal polypeptide and cholecystokinin also were reduced in schizophrenia, although not as profoundly as somatostatin or neuropeptide Y. In AD, cholecystokinin and vasoactive intestinal peptide were unchanged. Neuropeptide deficits in schizophrenics were more pronounced in the temporal and frontal lobes than in the occipital lobe. The mechanisms underlying these deficits in schizophrenia and AD are likely distinct. In schizophrenia, a common neural element, perhaps the cerebral cortical gaba-aminobutyric acid (GABA)-containing neuron, may underlie these deficits.

Apolipoprotein E-epsilon 4 allele and familial risk in Alzheimer's disease

Recent studies have found an association between presence of apolipoprotein E (APOE) epsilon 4 allele and Alzheimer's disease (AD). The present study compared the cumulative risk of primary progressive dementia (PPD) in relatives of AD probands carrying at least one copy of the epsilon 4 allele with the relatives of AD probands not carrying epsilon 4 and with relatives of non-demented controls. Our aim was to determine whether the familial aggregation of PPD in relatives of AD probands is primarily due to those carrying epsilon 4. Seventy-seven neuropathologically diagnosed AD patients were obtained as probands through our Alzheimer's Disease Research Center Brain Bank. AD probands were genotyped for APOE. As a comparison group, 198 non-demented probands were also included. Through family informants, demographic and diagnostic data were collected on 382 first-degree relatives (age > or = 45 years) of AD probands and 848 relatives of the controls. We found that the cumulative risk of PPD in both relatives of AD probands with and without the epsilon 4 allele was significantly higher than that in the relatives of non-demented controls. However, the increased risk in the relatives of AD probands with the epsilon 4 allele was marginally, but not significantly, lower than the risk in the relatives of probands without epsilon 4. A greater likelihood of death by heart diseases over developing PPD in relatives of AD probands with epsilon 4 (3.1-fold increase) was found compared to relatives of probands without epsilon 4 (1.7-fold increase), especially prior to age 70, although the difference was not statistically significant. The increased familial risk for PPD in the relatives of AD probands with the APOE-epsilon 4 allele relative to controls suggests that familial factors in addition to APOE-epsilon 4 are risk factors for AD. Differential censorship from increased mortality of heart diseases may have prevented a higher incidence of PPD among the relatives of probands with epsilon 4.

Issues in accelerating the pace of development for neuroprotective agents

Accelerating the pace of development for neuroprotective agents requires a number of advances in the therapeutics of Alzheimer disease. Identification of patients who are presymptomatic, by discovering early markers of Alzheimer disease will be essential. Clinical trials methodology must be devised to accommodate atypical outcome measures, prolonged trials, and large sample sizes without posing serious ethical considerations regarding placebo administration. Finally, regulatory issues that discourage development of drugs that will be in complicated, expensive and lengthy clinical trials need to be addressed. This paper reviews these issues, and offers some suggestions.

L-deprenyl and physostigmine for the treatment of Alzheimer's disease

The present study evaluated the safety of and obtained preliminary data on the cognitive effects of L-deprenyl and physostigmine in patients with Alzheimer's Disease. Seventeen outpatients with Alzheimer's Disease participated in a double-blind crossover study in which they received 4 weeks of L-deprenyl at a dose of 10 mg p.o., q.d., and 4 weeks of placebo in random order. During both the L-deprenyl and placebo periods, patients received cognitive assessments during physostigmine (0.5 mg) and placebo infusions separated by 2 days. The cognitive effects of these agents alone and in combination were measured with digit span, verbal fluency, list learning, praxis, delayed recall, and delayed recognition tasks. Fifteen patients completed the study. The two drugs, used alone or in combination, were safe and well tolerated. Analyses of variance demonstrated that neither physostigmine nor L-deprenyl, whether given alone or in combination, significantly improved cognition, when compared with the double placebo condition.

Normothermic continuous antegrade blood cardioplegia does not prevent myocardial edema and cardiac dysfunction

BACKGROUND

Normothermic continuous blood cardioplegia (BC) has been proposed to completely protect the myocardium during cardiac surgery. However, previous work from our laboratory suggests that BC could cause myocardial edema that produces cardiac dysfunction. The purpose of this present study was to evaluate the impact of BC on myocardial fluid balance and left ventricular function.

METHODS AND RESULTS

In 11 dogs, myocardial water content (MWC) was determined by microgravimetry. Myocardial lymph flow rate was measured after cannulation of the major prenodal cardiac lymphatic. Preload recruitable stroke work (PRSW) was calculated by sonomicrometry and micromanometry. The dogs were placed on normothermic cardiopulmonary bypass (CPB), and BC was delivered at either 80 to 90 mm Hg (BChigh; n = 6) or 40 to 50 mm Hg (BClow; n = 5) for 1 hour. Coronary sinus lactate and oxygen saturation monitoring demonstrated ischemia avoidance. BC was associated with substantial myocardial lymph flow rate decrease (P < .05) and myocardial edema development in both groups. MWC increased from 76.0 +/- 1.9% to 79.2 +/- 1.7% (P < .05) after 10 minutes of BChigh and from 75.9 +/- 0.6% to 78.9 +/- 1.4% (P < .05) after 30 minutes of BClow. PRSW decreased to 63 +/- 19% (BChigh) and 69 +/- 15% of control (BClow) at 30 minutes after CPB (P < .05). Myocardial lymph flow rate increases of threefold to fourfold that of control (P < .05) resulted in significant myocardial edema reduction associated with PRSW improvement to 71 +/- 17% (BChigh) and to 78 +/- 11% (BClow) at 2 hours after CPB.

CONCLUSIONS

We conclude that BC is associated with compromised cardiac function despite ischemia avoidance. This cardiac dysfunction is due to myocardial edema caused by the combination of increased myocardial microvascular fluid filtration and decreased myocardial lymph flow rate during BC.

A pen-and-paper human analogue of a monkey prefrontal cortex activation task: spatial working memory in patients with schizophrenia

In order to pursue the hypothesis that the dorsolateral prefrontal cortex is a source of cognitive deficit in schizophrenia, we developed an easily administered pen-and-paper human analogue of a visuospatial working memory task that in non-human primates activates the neurons of Walker area 46 (Goldman-Rakic, 1987). Compared to normal controls, schizophrenic patients made significantly greater errors in identifying where a visuospatial stimulus had been presented to them 30 and 60 seconds earlier, and these differences were significantly greater than in an immediate recall condition. These data suggest that schizophrenic patients have visuospatial working memory deficits that are sensitive to pen-and-paper versions of the tasks that activate the Walker area 46 in non-human primates. The availability of an easily administered test that may be associated with the functioning of the prefrontal cortex may enable more specific assessment of this brain region in humans.

Plasma 3-methoxy-4-hydroxyphenylglycol (MHPG) and clinical symptoms in Alzheimer's disease

Postmortem findings point to significant abnormalities in central noradrenergic function in Alzheimer's disease (AD) which may be associated with changes in peripheral markers. In this study, the relationship between the peripheral noradrenergic marker, plasma 3-methoxy-4-hydroxyphenylglycol (MHPG), and clinical symptoms was examined in 23 patients with probable AD. Basal MHPG levels correlated significantly with increased cognitive impairment (r = .58, p = .005), controlling for age, age at onset, gender, and time interval between plasma MHPG determination and cognitive testing. These results suggest that plasma MHPG increases as cognitive function in AD deteriorates, further supporting preliminary evidence for increases in noradrenergic indices in association with disease severity in AD.

Chronic elevation of secreted amyloid precursor protein in subcortically lesioned rats, and its exacerbation in aged rats

Subcortically lesioned rats were used as an animal model of some of the neurochemical and behavioral deficits of Alzheimer's disease (AD) to investigate the in vivo expression and metabolism of amyloid precursor protein (APP). Previously, the rapid and persistent induction of APP was described in cerebral cortices after disruption of its cholinergic, serotonergic, or noradrenergic afferents. In the present study, this induction was found to lead to the elevated secretion of APP into the cerebrospinal fluid of lesioned animals. Lesions of the forebrain cholinergic system in aged rats caused an even greater increase in the CSF levels of secreted APP. Antibodies to the extracellular domain of APP detected the protein whereas antibodies to the cytoplasmic region did not, indicating that the APP present in CSF was of the soluble form. Immunoprecipitation with an A beta sequence-specific antibody followed by immunoblot analysis indicated that a significant portion of secreted APP was of the species that contains at least the first 28 amino acids of the A beta sequence (APP gamma or APPA beta). By contrast, very low levels of A beta peptide were detected in CSF. The secretion was accompanied by an elevation of cellular C-terminal fragments of the APP in the lesioned cortex. Consistent with our previous results, this increased APP secretion was caused by lesions of subcortical cholinergic and serotonergic systems. The postlesion time course of APP secretion showed an initial reduction of APP (1 hr postlesion) in CSF followed by an eventual twofold elevation 1-6 weeks later. These results indicate that the induction of APP in response to loss of subcortical innervation leads to elevated secretion of a soluble form of cortically derived APP that contains significant portions of the A beta sequence.

A closed eye contact lens model of corneal inflammation. Part 2: Inhibition of cytochrome P450 arachidonic acid metabolism alleviates inflammatory sequelae

PURPOSE

The authors have previously shown a marked increase in corneal epithelial arachidonic acid metabolism to 12-hydroxyeicosatetraenoic acid (12-HETE) and 12-hydroxyeicosatrienoic acid (12-HETrE) in a model of closed eye-contact lens wear. Their formation was predominantly cytochrome P450-dependent and significantly correlated with inflammatory score and corneal thickness. In the current study, the authors used stannous chloride to inhibit the epithelial cytochrome P450-dependent synthesis of 12-HETE and 12-HETrE to assess the role of these eicosanoids as mediators of the inflammatory response to contact lens wear in the closed eye.

METHODS

Hydrogel contact lenses were soaked in stannous chloride (100 micrograms/ml) or vehicle and fitted to the rabbit eye in stacked fashion (two lenses/eye), followed by a silk suture tarsorrhaphy of approximately 90%. Eyes were analyzed over a 7-day period for inflammatory responses through slit lamp biomicroscopy, subjective inflammatory scoring, ultrasonic pachymetry, and corneal epithelial [1-14C]-arachidonic acid metabolism.

RESULTS

Closed eye-hydrogel contact lens wear resulted in a progressive anterior surface inflammatory response. Coinciding with these events was a time-dependent increase in corneal thickness and 12-HETE and 12-HETrE production rates by corneal epithelial homogenates. Treatment of the lenses with stannous chloride (100 micrograms/ml) significantly attenuated by day 7 the inflammatory score (56% decrease), corneal thickness (17% decrease), and 12-HETE and 12-HETrE synthesis (77% and 71% decrease, respectively).

CONCLUSIONS

This study further substantiates the involvement of cytochrome P450, through the synthesis of 12-HETE and 12-HETrE, in the inflammatory response associated with hydrogel contact lens wear in the closed eye. Thus, inhibition of cytochrome P450, with subsequent decreases in 12-HETE and 12-HETrE, may attenuate the pathophysiologic response to contact lens wear in the closed eye.

Age at onset and familial risk in Alzheimer's disease

OBJECTIVE

The authors investigated the relationship between probands' age at onset of Alzheimer's disease with the risk of primary progressive dementia in the probands' first-degree relatives.

METHOD

Two hundred probands with clinically diagnosed Alzheimer's disease and 179 nondemented elderly probands were recruited from the Mount Sinai Alzheimer's Disease Research Center, located at Mount Sinai Hospital and the Bronx Veterans Affairs Medical Center. Demographic and diagnostic data were collected on 1,398 of the first-degree relatives of the probands with Alzheimer's disease and 955 first-degree relatives of the nondemented probands.

RESULTS

Cox proportional hazards regression analysis showed a significant inverse relationship between age at onset of Alzheimer's disease in probands and greater familial risk in their relatives. Follow-up analyses indicated that the most commonly used age at onset cutoff point--65 years--was one of the points where an association with familial aggregation is least likely to be revealed; other onset cutoff ages (e.g., 55, 70, and 75) better identified Alzheimer's disease groups with differing familial/genetic risks.

CONCLUSIONS

The authors conclude that patients with an earlier age at onset of Alzheimer's disease are more likely to have relatives with Alzheimer's disease than are patients with a later age at onset of the disease. An onset age of 70 best differentiated probands whose relatives were at higher risk from those whose relatives were at lower risk.

Myocardial edema and compromised left ventricular function attributable to dirofilariasis and cardiopulmonary bypass in dogs

We investigated the relation between left ventricular dysfunction and myocardial edema in dogs with heartworm (Dirofilaria immitis) infection that were undergoing cardiopulmonary bypass. Dogs with and without D immitis were anesthetized by continuous thiopental infusion and were mechanically ventilated. Sonomicrometry crystals were placed on the long and short axes of the left ventricle, and a Millar pressure transducer was placed in the left ventricular chamber. Pressure-volume loops were digitized and continuously recorded. Dogs with and without D immitis were placed on standard hypothermic cardiopulmonary bypass, with 1 hour of aortic cross-clamp. Wet-to-dry weight ratio corrected for residual blood volume was used to quantitate the volume of myocardial edema. Preload recruitable stroke work was used as a preload-independent index of systolic function. Tau, the isovolumic relaxation time constant, was determined to assess diastolic relaxation. Dogs with D immitis had increased baseline myocardial wet-to-dry weight ratio. After cardiopulmonary bypass, myocardial edema increased in all dogs. Acute edema attributable to cardiopulmonary bypass decreased preload recruitable stroke work in all dogs of both groups, and dogs with D immitis could not be weaned from cardiopulmonary bypass. Myocardial edema increased diastolic relaxation times (tau) in dogs with and without D immitis. We conclude that cardiopulmonary bypass and heartworm infection induce myocardial edema. This edema compromises left ventricular systolic and diastolic function making D immitis an important confounding factor in weaning dogs from cardiopulmonary bypass.

Neurochemical correlates of dementia severity in Alzheimer's disease: relative importance of the cholinergic deficits

Cholinergic markers, neuropeptides, and amines and their metabolites were sampled from identical specimens across 10 neocortical regions in a large sample of Alzheimer's disease (AD) cases and controls. Levels of choline acetyltransferase, acetylcholinesterase, somatostatin, corticotropin-releasing factor, serotonin, and 5-hydroxyindoleacetic acid were significantly reduced in AD versus controls. After data reduction, the most descriptive neurochemical indices were used to examine the relationship of neurochemical measures and dementia severity within the AD sample, controlling for age effects. Dementia severity ratings were based on antemortem assessments (46.9% of AD sample) and postmortem chart review (53.1% of the AD sample). Choline acetyltransferase activity was highly correlated with clinical dementia ratings across the neocortex of the AD cases. Somatostatin and corticotropin-releasing factor levels were correlated with dementia severity only when control cases were included in the analyses. None of the amines, their metabolites, or the neuropeptides quantified related significantly to dementia severity in the AD cohort. These data (a) confirm the strong association of cholinergic deficits with functional impairment in AD and show that this association is independent of age and (b) suggest that of all the neurochemical species quantified, the cholinergic indices may be unique in their association with dementia severity.

Myocardial edema, left ventricular function, and pulmonary hypertension

Left ventricular dysfunction has been reported in both experimentally induced and clinical pulmonary hypertension. However, the mechanism by which pulmonary hypertension causes left ventricular dysfunction is unknown. We hypothesized that acute pulmonary hypertension causes left ventricular myocardial interstitial edema and that it is this edema that causes left ventricular dysfunction. In pulmonary artery-banded or sham-operated dogs, left ventricular diameter (septal-free wall axis) and pressure were measured using sonomicrometry crystals and a micromanometer, respectively. These measurements were used to calculate preload recruitable stroke work (PRSW), an index of contractility, and the rate of active relaxation (tau) to assess systolic and diastolic left ventricular function, respectively. After 3 h of pulmonary arterial hypertension or control, the dogs were killed and the left ventricles were excised to determine wet-to-dry weight ratios. The wet-to-dry weight ratios were significantly higher in the pulmonary artery-banded dogs (3.57 +/- 0.12) than in the sham-operated dogs (3.41 +/- 0.17). PRSW decreased to 56.8 +/- 30.3% of control after 3 h of pulmonary hypertension. tau Slowed significantly from 29.8 +/- 5.8 ms at baseline to 63.6 +/- 30.4 ms after 3 h of pulmonary arterial hypertension. There were no differences in PRSW or tau in the sham-operated dogs. We conclude that pulmonary hypertension causes left ventricular myocardial interstitial edema, which results in both systolic and diastolic left ventricular dysfunction.