Changes in cerebral neurotransmitters and metabolites induced by acute donepezil and memantine administrations: A microdialysis study

Cholinesterase inhibitors including donepezil, rivastigmine, and galantamine and the N-methyl-D-aspartate (NMDA) antagonist, memantine are the medications currently approved for the treatment of Alzheimer's disease (AD). In addition to their beneficial effects on cognitive and functional domains typically disrupted in AD, these agents have also been shown to slow down the emergence of behavioral and psychotic symptoms associated with this disease. However, the underlying mechanisms for these therapeutic effects remain poorly understood and could involve effects of these medications on non-cholinergic or non-glutamatergic neurotransmitter systems respectively. These considerations prompted us to initiate a series of investigations to examine the acute and chronic effects of donepezil (Aricept (+/-)-2,3-dihydro-5,6-dimethoxy-2-[[1-(phenylmethyl)-4-piperidinyl]methyl]-1H-inden-1-1 hydrochloride and memantine (1-amino-3,5-dimethyladamantane hydrochloride C12H21N.HCl)). The present study focuses on the acute effects of donepezil and memantine on brain extracellular levels of acetylcholine, dopamine, serotonin, norepinephrine and their metabolites. We assayed changes in the ventral and dorsal hippocampus and the prefrontal and medial temporal cortex by microdialysis. Memantine resulted in significant increases in extracellular dopamine (DA), norepinephrine (NE), and their metabolites, in the cortical regions, and in a reduction of DA in the hippocampus. Donepezil produced an increase in extracellular DA in the cortex and in the dorsal hippocampus. Norepinephrine increased in the cortex; with donepezil it increased in the dorsal hippocampus and the medial temporal cortex, and decreased in the ventral hippocampus. Interestingly both compounds decreased extracellular serotonin (5HT) levels. The metabolites of the neurotransmitters were increased in most areas. We also found an increase in extracellular acetylcholine (ACh) by memantine in the nucleus accumbens and the ventral tegmental area. Our results suggest both region and drug specific neurotransmitter effects of these agents as well as some similarities. We conclude that drugs influencing cognitive mechanisms induce changes in a number of neurotransmitters with the changes being both region and drug specific. Release and metabolism are altered and extracellular neurotransmitter levels can be increased or decreased by the drugs. Other studies are in progress to determine the pharmacological effects associated with chronic treatment with these compounds, which may be more pertinent to the clinical situation in which patients take these medications for months or years.

Sex-related differences in nortriptyline-induced side-effects among depressed patients

1. Men and women may differ in their pharmacokinetic responses to tricyclic antidepressants (TCAs), in a number of autonomic indices, and in various adrenergic receptor mediated responses. Emerging evidence also suggests that women may have a lower rate of serotonin synthesis in brain and a greater sensitivity to the depressant effects of tryptophan depletion, relative to men. However, sex-related differences in TCA-induced side-effects, including increases in heart rate (HR), dry mouth, constipation, and difficulty urinating, has not been systematically investigated. 2. The authors examined potential sex-related differences in the pattern of side-effects during treatment with nortriptyline (NT), a TCA that is still widely used. Seventy-eight healthy outpatients who met Research Diagnostic Criteria and DSM-III-R criteria for major depression participated in a double-blind, randomized parallel trial of NT versus placebo. 3. Each subject was acutely challenged with either placebo or 50 mg NT prior to and after a 6-week treatment with NT. NT doses were adjusted weekly to maintain therapeutic plasma levels. Patients were assessed at multiple time points to detect the presence of NT-induced side-effects. 4. The initial, single (50 mg) dose of NT significantly increased supine HR. Six-week treatment with NT was found to significantly increase supine and sitting HRs, irrespective of sex. In rechallenge with the single NT dose, there were no significant effects on HR. 5. When sex-related differences were examined, HR increases were greater in men than women during weeks 4 through 6 of the NT treatment, although no sex-related differences were present in plasma NT levels or metabolites. In addition, there was a significant NT to placebo difference in self-rated dry mouth for women during all 6-weeks of treatment, whereas men showed a significant NT-placebo difference during weeks 3 and 5. 6. The results suggest the presence of sex-related differences in elevated supine HR response during the course of 6-week NT treatment. Depressed men may be more susceptible to NT-induced increases in supine HR than women.

White matter abnormalities in HIV-1 infection: a diffusion tensor imaging study

Diffuse white matter pallor is the most frequent neuropathological feature of HIV-1 infection and has been found to be particularly prominent in the advanced stages of the disease. The purpose of this study was to determine whether subtle white matter abnormalities can be detected in medically stable, ambulatory HIV-1 patients, in vivo, using diffusion tensor imaging (DTI). DTI is a magnetic resonance imaging (MRI) technique that is uniquely suited for the study of subtle white matter abnormalities. DTI was performed in six HIV-1 patients and nine controls. The two groups were similar in age. Abnormal fractional anisotropy was found in the white matter of the frontal lobes and internal capsules of the HIV-1 patients, in the absence of group differences in mean diffusivity, computed proton density, and computed T2. DTI may be more sensitive than conventional MRI methods for detecting subtle white matter disruptions in HIV-1 disease.

Risperidone in the treatment of elderly patients with psychotic disorders

The authors evaluated the safety, tolerability, and efficacy of risperidone in 103 elderly patients (mean age, 71 years) with schizophrenia (75%) or schizoaffective disorder (25%). Using the Extrapyramidal Symptoms Rating Scale (ESRS), Positive and Negative Syndrome Scale (PANSS), and Clinical Global Impression (CGI) scale, they conducted a prospective, open-label, 12-week trial in 14 psychiatric centers in the United States. Patients' symptoms were assessed at baseline and over a 12-week period. At endpoint, ESRS scores were significantly reduced, as were PANSS total and subscale scores. There were no clinically significant changes in electrocardiograms, laboratory test results, or vital signs. Risperidone was well tolerated and efficacious in elderly patients with schizophrenia or schizoaffective disorder.

Decreases in plasma A beta 1-40 levels with aging in non-demented elderly with ApoE-epsilon 4 allele

This report examines plasma amyloid beta proteins A beta 40 and A beta 42 and apolipoprotein E (apoE) levels and their relationships with age in non-demented older adults with (N = 32) or without the apoE-epsilon 4 allele (N = 94). A beta levels did not differ between the groups whereas the epsilon 4 allele was associated with a significant reduction in plasma apoE. In subjects with the epsilon 4 allele, increasing age was associated with significant reduction in plasma A beta 40. Subjects without the epsilon 4 allele showed a significant positive correlation between A beta 40 and A beta 42 levels. There was also a significant correlation between plasma A beta 40 and apoE levels in all subjects.

The acute and chronic performance effects of alprazolam and lorazepam in the elderly: relationship to duration of treatment and self-rated sedation

We examined the acute performance and sedative effects of single high and low doses of alprazolam and lorazepam, both before and after chronic, 3-week b.i.d. treatment in elderly adults. The effects of chronic treatment also were examined in this parallel, double-blind, placebo-controlled study. Initial acute low doses significantly impaired total recall and increased intrusion errors. High doses also impaired delayed recall and critical flicker fusion threshold (CFF). Only chronic treatment with high-dose alprazolam increased intrusions and self-rated sedation. Single-dose rechallenge after chronic treatment was associated with significantly less impairment than the initial challenge in memory tasks but not in the discriminant reaction time (DRAT) task. For most memory measures, the development of tolerance was only partial; rechallenge still produced significant deficits in relation to placebo. The development of tolerance was task-specific and depended on drug type and dosage. Despite impairments in various memory functions, CFF, and DRAT, volunteers did not report significant drug-induced changes in sedation.

Cerebrospinal fluid C3a increases with age, but does not increase further in Alzheimer's disease

Complement activation is present in the brain in Alzheimer's disease (AD), and C1q concentrations are decreased in AD cerebrospinal fluid (CSF). To determine whether concentrations of other complement proteins are also altered in AD CSF, we measured concentrations of C3a and SC5b-9 in CSF from patients with probable AD (n = 19), normal aged controls (n = 11), and normal younger controls (n = 15). C3a concentrations were similar between AD and aged controls, but threefold higher than in younger controls (p < 0.05 vs. both groups). A similar pattern was found with SC5b-9, though the increase was only twofold and statistically significant only for AD vs. younger controls. These results suggest that an increased generation of complement proteins in localized areas of the AD brain does not result in elevated concentrations of these proteins in CSF, compared with age-matched controls. Increased C3a (and, to a lesser extent, SC5b-9) in aged controls may be due to increased complement activation, increased central nervous system production, and/or blood-brain barrier leakage of these proteins.

Immunocytochemical detection of anti-hippocampal antibodies in Alzheimer's disease and normal cerebrospinal fluid

Immunocytochemical staining was performed to investigate the presence of anti-hippocampal antibodies in cerebrospinal fluid (CSF) from patients with probable Alzheimer's disease (AD) (n = 19), aged normal controls (n = 9), and young normal controls (n = 10). Marked staining of neurons in the granule cell layer of the dentate gyrus and in pyramidal neurons in CA1-3 of the rat hippocampus was observed in 5 AD CSF samples (26%), 1 aged control sample (11%), and 1 young control sample (10%). These differences were not statistically significant. One of the immunoreactive AD CSF specimens also contained high concentrations of C5b-9, the membrane attack complex. The infrequent occurrence of anti-hippocampal antibodies in AD CSF, and the detection of similar immunoreactivity in control CSF specimens, suggest that these antibodies are unlikely to play a role in the neurodegenerative process in most individuals with AD. However, elevated C5b-9 concentration in an AD CSF specimen with marked immunoreactivity to hippocampal neurons suggests the possibility that anti-neuronal antibodies may contribute to complement activation in some AD patients.

Ceruloplasmin is increased in cerebrospinal fluid in Alzheimer's disease but not Parkinson's disease

Although the pathophysiology of Alzheimer's disease (AD) and Parkinson's disease (PD) is unknown, altered brain antioxidative mechanisms have been found in both disorders. Ceruloplasmin (CP) and transferrin (TF) interact to limit concentrations of free ferrous iron (Fe2+), and thus play an important role in antioxidant defense in serum; both proteins are also produced in brain, where their significance as antioxidants is unknown. We quantified concentrations of CP and TF by immunoassay in AD (n = 17) and PD (n = 12) cerebrospinal fluid (CSF) to determine whether these proteins could serve as disease markers. CP was increased versus aged normal subjects (n = 11) in AD (p < 0.05) but not PD CSF, whereas TF concentrations did not differ between groups. CP levels have been reported to be elevated in some brain regions in AD, and increased CP in AD CSF may reflect this finding. Systemic inflammation and oxidative stress are major factors stimulating hepatic CP synthesis, and it remains to be determined whether increased CP concentrations in AD CSF and brain follow from similar mechanisms.

Aging, emotional states, and memory

OBJECTIVE

This study compared the relation between negative mood states and memory in young and elderly subjects.

METHOD

Forty-five normal, healthy young volunteers (ages 19-35 years) and 45 normal, healthy elderly volunteers (ages 60-78 years) were administered a verbal list-learning task and self-rated scales of affective states.

RESULTS

The elderly group, but not the young group, consistently exhibited significant correlations between their performance on verbal recall measures and their ratings of their anxiety, depression, and withdrawal; i.e., within the elderly group, higher levels of negative affective states were associated with poorer memory.

CONCLUSIONS

These findings indicate that aging modulates the relation between emotional state and memory functions, and they are consistent with the hypothesis that the elderly are more vulnerable than the young to the adverse effects of negative emotional states on memory. Therefore, even in normal elderly individuals without diagnosable psychopathology, negative affective states (such as anxiety and depression) may interfere with memory functioning.

Milacemide: a placebo-controlled study in senile dementia of the Alzheimer type

OBJECTIVE

Milacemide, a MAO-B inhibitor that is also a prodrug for glycine, was tested as a treatment for senile dementia of the Alzheimer type (SDAT) because of its potential for enhancing cognition in animal models of impaired learning and memory.

DESIGN

Double-blind, placebo-controlled, randomized clinical trial.

SETTING

Sixteen study sites, both university-affiliated and private.

PATIENTS

A total of 228 outpatients (116 men and 112 women) with SDAT, ranging in age from 49-93 years.

INTERVENTION

1200 mg/day milacemide treatment for 1 month (113 patients received milacemide, and 115 patients received placebo).

MAIN OUTCOME MEASURES

Alzheimer's Disease Assessment Scale and the Mini-Mental State Examination.

RESULTS

Milacemide-treated SDAT patients did not show significant improvement in any of the outcome measures used. Significant elevations in liver enzymes in four subjects were of sufficient magnitude to necessitate withdrawal from the study.

CONCLUSIONS

Milacemide does not appear to be an effective treatment in enhancing cognition in SDAT patients.

Increased CSF HVA response to arecoline challenge in Alzheimer's disease

The effects of the muscarinic agonist, arecoline, on the concentration of homovanillic acid (HVA) in the cerebrospinal fluid of patients with Alzheimer's disease (AD) and controls were examined. Patients and controls received intravenous infusions of arecoline and a lumbar puncture was performed four hours after the infusion began. Arecoline induced a significant increase in the concentration of HVA in cerebrospinal fluid of Alzheimer's disease patients (p < .01) but not in controls. The differential HVA response to a muscarinic agonist in Alzheimer's disease is suggestive of an alteration in muscarinic receptor response. This finding may have potential implications for the pathophysiology and treatment of Alzheimer's disease.

Glutamate and other CSF amino acids in Alzheimer's disease

The authors compared CSF amino acid levels of 10 patients with mild to moderate dementia and probable Alzheimer's disease who had never received antidepressant or neuroleptic medication with those of 10 normal subjects of similar age. The Alzheimer's patients had significantly higher levels of CSF glutamate. This finding was not related to age, sex, or severity of dementia. Elevated CSF glutamate may reflect greater glutamatergic activity early in the course of Alzheimer's disease. The authors speculate that the excitotoxic effects of glutamate may contribute to progressive neuronal loss in Alzheimer's disease.

Equivalence of five forms of the Selective Reminding Test in young and elderly subjects

This study evaluated the equivalence of five forms of the Selective Reminding Test, a widely used measure of verbal learning, 45 normal young and 45 normal elderly subjects were randomly administered three of the five test forms on three separate sessions. The five forms generally correlated well with one another and were of comparable difficulty, suggesting adequate test equivalence. Four of the five forms were particularly well matched.

Effects of antidepressants on human performance: a review

Despite widespread use of antidepressants, major gaps remain in our knowledge of the effects of antidepressants on human performance. While most single-dose studies with normal subjects have suggested that the more sedating tricyclic antidepressants tend to produce impairment, the effects of antidepressant treatment in clinical populations have been less thoroughly examined, with both drug-induced impairment and improvement reported. This review suggests that factors such as age, diagnosis, drug plasma concentration, and length of treatment need to be explored to establish the effects of antidepressants on performance in clinical populations.

CSF corticotropin-releasing factor (CRF) in Alzheimer's disease: its relationship to severity of dementia and monoamine metabolites

The concentration of corticotropin-releasing factor-like immunoreactivity (CRF-LI) in the cerebrospinal fluid (CSF) of 15 probable Alzheimer's disease (AD) patients with mild to moderate dementia and 10 neurologically normal age-matched controls was examined. There were no significant alterations in the mean CSF CRF-LI concentration in AD compared to controls. However, in the AD group, CSF CRF-LI correlated significantly with the global neuropsychological impairment ratings, suggesting that greater cognitive impairment was associated with lower CSF CRF-LI concentrations. There was a significant reduction in the CSF concentration of homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) in the AD patients, and there was a positive correlation between the concentration of CRF-LI and 5-HIAA in CSF. This latter finding suggests that serotoninergic neuronal systems may interact with CRF-containing neurons.

CSF GABA in caregiver spouses of Alzheimer patients

The authors studied CSF gamma-aminobutyric acid (GABA) in 14 Alzheimer patients and nine age-matched normal subjects. The five normal subjects who were wives of the demented patients had higher CSF GABA concentrations than the four normal subjects without demented spouses.

Loss of the cortisol response to naltrexone in Alzheimer's disease

The administration of a single dose of the opiate antagonist naltrexone (NT) was accompanied by significant elevations in plasma cortisol in normal elderly subjects; in contrast, the cortisol response to NT was absent in individuals of comparable age with Alzheimer's disease (AD). The differential effect of AD on the cortisol response was not accompanied by a significant group difference in plasma prolactin in response to NT administration. Furthermore, this differential cortisol response to NT was not associated with any evident differences in age, sex ratio, plasma levels of naltrexone or its major metabolite beta-naltrexol, or with differences in measures of nonspecific stress, such as plasma free MHPG, pulse, or blood pressure, between the two groups. The absence of the well-characterized cortisol response to NT in AD, together with other reports of abnormal responses to other pharmacological challenges, suggests that neuroendocrine abnormalities might be an important concomitant and possibly a central contributor to the pathophysiology of Alzheimer's disease.

Comparison of methods for analysis of CSF proteins in patients with Alzheimer's disease

Cerebrospinal fluid (CSF) from patients with Alzheimer's disease (AD) and controls was analyzed by one- and two-dimensional gel electrophoresis, electron microscopy, and fluorescence microscopy with thioflavin S staining. In CSF from patients with AD, abnormal proteins were found following two-dimensional gel electrophoresis and silver staining. In CSF samples from most of the AD patients studied, a highly argentophilic material was detected upon silver staining the stacking gel of the one-dimensional gels. Electron microscopy of material eluted from the stacking gel showed fibers of approximately 7-10 nm diameter, with some twisting; properties consistent with paired helical filaments or amyloid. Furthermore, material with the characteristics of amyloid (fiber diameter ranging from 4-10 nm) was found in the CSF sediment. The CSF from AD patients had significantly elevated numbers of yellow fluorescent particles following thioflavin S staining when compared with age-matched, other neurological disease controls. We did not see an increase in autofluorescence, indicating that thioflavin S staining is specific. Our data suggest that AD CSF contains plaque amyloid and possibly proteins from neurofibrillary tangles. The thioflavin S staining method appears to have potential for development as a diagnostic tool.

Prospective strategies for cholinergic interventions in Alzheimer's disease

The cholinergic hypothesis of memory dysfunction has guided most of the recent proposals for treating the primary symptoms of AD. The efficacy of these treatments has been severely limited. This review examines two major lines of evidence which suggest that the cholinergic hypothesis may have to be expanded and revised. The cholinergic hypothesis focuses on pre-synaptic defects. It assumes cholinoceptive neurons would function normally with adequate stimulation. Evidence is not sufficient to support this assumption. In addition, dissociations have been demonstrated between muscarinic receptor number and functional response of cholinoceptive neurons. Various measures are proposed to investigate the functional integrity of muscarinic receptors in AD patients. AD often has been characterized as a disorder produced by generalized cholinergic hypoactivity. Evidence for cortisol hypersecretion, abnormal dexamethasone suppression, and the occurrence of depressive symptoms, motoric dysfunction and sleep abnormalities in AD patients is more consistent with regional cholinergic hyperactivity than generalized hypoactivity. Resolution of these discrepancies could shed new light on the pathophysiology and treatment strategies for AD. Cholinoceptive neurons could be hypersensitive, subsensitive or have unaltered responsivity. These options would have very different treatment implications. New developments in outcome assessment which are capable of discriminating varieties of differential response to treatment can spur treatment development and improve quality of care for patients with complex disorders such as AD.

Electrophoresis and immunoblot of cerebrospinal fluid proteins in spasmodic torticollis

Protein patterns of cerebrospinal fluid (CSF) from patients with spasmodic torticollis (ST) were investigated to determine whether abnormalities previously reported could be detected and further identified. CSF was collected from 12 patients with ST and 6 normal controls. The CSF proteins were analyzed using sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis and silver staining. In 11 of the 12 patients with ST, a CSF protein pattern was observed which differed from that in the controls. The identity of the abnormal proteins was ascertained by blotting and immunostaining with specific antisera to IgG and ceruloplasmin (Cp). CSF from 2 of 12 patients had distinct bands staining for IgG and 7 had abnormal immunostaining for Cp.

Multiple, single-dose naltrexone administrations fail to effect overall cognitive functioning and plasma cortisol in individuals with probable Alzheimer's disease

A double-blind placebo-controlled study was conducted in 10 individuals with probable Alzheimer's disease to assess the effects of varying doses of Naltrexone (0, 25, 50 and 100 mg) on cognitive functioning and on plasma cortisol. Each individual participated in four separate sessions at least three days apart. Naltrexone was found to improve performance in only one of the six psychometric tasks employed (Token Test). However, enhancement of Token Test performance was limited to the 25 mg Naltrexone dose and was mainly the result of an improvement on the part of the two most severely impaired patients. In contrast to the previous reports of elevations of plasma cortisol following administration of opiate antagonists to younger, non-demented subjects, Naltrexone administration failed to produce any significant increase in plasma cortisol in Alzheimer's patients.

Memory performance in individuals with primary degenerative dementia: its similarity to diazepam-induced impairments

Impairments of memory storage and retrieval produced by diazepam (2.5 mg, 5 mg, and 10 mg) in normal elderly individuals were compared to those observed in patients with primary degenerative dementia tested under nondrug conditions. The highest diazepam dose affected retrieval as well as storage processes in Buschke's "selective reminding" task, producing impairments qualitatively similar to those shown by demented patients. All diazepam doses impaired Buschke task performance in the normal elderly individuals; normal young subjects, in contrast, showed no impairment with a low (2.5 mg) diazepam dose.

Chelation therapy. Unproved modality in the treatment of Alzheimer-type dementia

Despite a dramatic increase in the understanding of the neuropathologic and neurochemical alterations accompanying Alzheimer's disease, by far the largest cause of progressive and incapacitating cognitive dysfunction in the elderly, physicians have as yet no pharmacologic agent that can be prescribed safely either to arrest or reverse this decline. This lack of effective therapeutic agents is contributing to the use by an increasing number of health professionals, including physicians and concerned families, of unproved, costly, and potentially dangerous modalities, such as chelation therapy. The purpose of this paper is to describe some individuals with Alzheimer-type dementia who have undergone chelation therapy.

Clinical ratings: relationship to objective psychometric assessment in individuals with dementia

The efficacy of drugs for the treatment of memory impairment in elderly patients with dementia is frequently established by a combination of subjective and objective psychological assessments. Often these assessments produce conflicting results. To throw some light on the relation between subjective and objective assessments, we examined the correlations of subjective ratings on the Sandoz Clinical Assessment—Geriatric (SCAG) and scores on objective cognitive tests of demented patients (9 men and 14 women) being screened for participation in an experimental drug trial. Our results showed agreement between some SCAG scores and performance on tests assessing orientation and information and global measures of memory and cognitive function. Subjective and objective assessments were not redundant, however; both should be included when evaluating the efficacy of pharmacological treatments for dementia.

Increased sensitivity of the elderly to the central depressant effects of diazepam

The effects of diazepam on memory and psychomotor performance in healthy elderly (N = 12) and young (N = 12) individuals were examined. Diazepam was administered acutely in a single, oral 2.5 mg dose. Diazepam impaired memory, both immediate and delayed recall, and psychomotor performance in the elderly subjects. In addition, the drug caused an increase in self-reported sedation in elderly subjects but not in young subjects. These findings suggest an age-related increase in the sensitivity of elderly individuals to the central depressant effects of diazepam.

Event-related potential in Alzheimer disease

Auditory event - related potentials were studied in 20 patients with SDAT and 20 age and sex matched normal controls. Patients with SDAT showed prolonged latencies of N200 and P300 components. The mean amplitudes of N200 and P300 were lower in the SDAT group. This reflects the impairment of the speed of neural processing in patients with SDAT. There were no significant correlations of the progression of P300 latencies from mild to severe dementia according to global dementia scales.

The therapeutic potential of thyrotropin releasing hormone (TRH) in Alzheimer's disease (AD)

In recent years it has been established that patients with AD have a relatively specific loss of cerebral cortical and hippocampal cholinergic nerve terminals. This may be a reflection of degeneration of cholinergic neurons originating in the nucleus basalis of Meynert and septum which project to the cortex and hippocampus, respectively. In view of the long-standing association of cholinergic mechanisms with cognitive processes and the recognition of selective cholinergic deficits in AD, therapeutic attempts to enhance CNS cholinergic function have been undertaken in patients with AD. While only limited success with this strategy has been achieved to date, the use of TRH may offer a novel, yet rational, approach to treating AD. This assumption is predicated on the extensive literature documenting unique, facilitatory interactions of this peptide with cholinergic neurons throughout the neuraxis. Furthermore, the same rationale may account for the recently reported therapeutic benefit of TRH in patients with amyotrophic lateral sclerosis, which like AD, is a disease whose symptoms are manifested through a progressive degeneration of a subpopulation of CNS cholinergic neurons.

Treatment-resistant depression in an elderly patient with pancreatic carcinoma: case report

A case is reported of a recurrent and treatment-resistant depression with a positive DST in an individual in whom adenocarcinoma of the pancreas was eventually diagnosed. Following excision of the tumor, there was increased therapeutic response to antidepressants and normalization of the DST.

Proline in the cerebrospinal fluid of normal subjects and Alzheimer's-disease patients, as determined with a new double-labeling assay technique

Past studies have implicated proline involvement in the function of memory and learning. A new micromethod has been developed that is suitable for measuring proline accurately in as little as 0.1 ml of CSF. In normal human CSF, the average proline level was found to be consistently about 1.3 microM. In the CSF of patients with Alzheimer's disease and mixed dementias, the levels of proline showed no statistically significant difference from proline levels in the CSF of normal controls. Furthermore, the proline levels in the CSF of the Alzheimer's disease patients did not reflect, consistently, the cognitive deficits or the symptomatic severity of the disease. Proline levels in CSF showed no statistically significant change with the age of individuals tested.

Lithium-induced accentuation of extrapyramidal symptoms in individuals with Alzheimer's disease

Lithium treatment in 9 elderly individuals with Alzheimer's disease led to a marked accentuation of extra-pyramidal symptoms (EPS) in 5 of 6 patients with preexisting EPS. EPS scores significantly correlated with plasma and RBC lithium levels. Lithium treatment had no such effects in the 3 patients without preexisting extrapyramidal symptoms.

Myalgia and elevation in muscle creatine phosphokinase during zimelidine treatment

The authors report a case involving a 65-year-old woman with DSM-III criteria for major unipolar depression in whom the administration of zimelidine, a potent and selective 5-hydroxytryptamine reuptake inhibitor, led to the development of a hypersensitivity reaction characterized by a severe headache, low grade fever, abnormal liver enzymes, and generalized myalgia 10 days after initiation of treatment. The most novel aspect of this hypersensitivity reaction to zimelidine was the development of abnormalities in muscle creatine phosphokinase in conjunction with the myalgia.

Lithium-induced increases in red blood cell choline and memory performance in Alzheimer-type dementia

To investigate the relationship between RBC choline and memory in Alzheimer-type senile dementia (SDAT), lithium carbonate was administered to 14 SDAT patients in doses of 400-600 mg/day for 5 weeks. A battery of memory tests was administered at baseline and at weekly intervals. Five patients with serum concentrations below 0.6 meq/liter developed neurotoxicity and were dropped from further analysis. For the remaining patients, Li+ with mean serum concentrations up to 0.6 meq/liter did not alter memory scores significantly. The dramatic increases in RBC choline during the study, however, suggest that RBC choline is not correlated with memory functioning in SDAT.

Adverse effects of single therapeutic doses of diazepam on performance in normal geriatric subjects: relationship to plasma concentrations

Elderly normal volunteers (N = 12, mean age 70.4 years) were administered placebo or diazepam 2.5, 5, 10 mg in four consecutive sessions separated by at least a 1-week interval. Memory and psychomotor performance and plasma diazepam concentrations were assessed at baseline and at 1 and 3 h following drug administration. Significant impairments were found in response to all doses of diazepam. The maximum impairment occurred at 1 h, which coincided with the highest plasma concentration of the drug.

Prediction of serum cortisol response to dexamethasone in normal volunteers: a multivariate approach

Dexamethasone (DEX, 0.5 mg orally at 11 PM) challenge was used for the assessment of hypothalamic-pituitary-adrenal (HPA) activity in 20 normal volunteers. Age and pre-DEX serum cortisol levels were theè evaluated as predictors of postDEX serum cortisol levels using step-wise multiple regression analysis. Both age and preDEX serum cortisol levels were significant predictors of postDEX serum cortisol levels. It is suggested that the adjustment for age and preDEX serum cortisol level could be useful for the interpretation of abnormal postDEX levels.

Russell's revised Wechsler Memory Scale in the evaluation of dementia

Matched 31 elderly normals and 25 patients with suspected Alzheimer's disease for age and education and administered the Revised Wechsler Memory Scale (WMS-R). The patient group performed significantly less well than the control group on all WMS-R subtests. A bimodal distribution of Percent Retained scores was noted in the patient group, but not in the control group. Results are discussed with respect to the clinical utility of the WMS-R as a memory screening procedure.

Aging and cortisol resistance to suppression by dexamethasone: a positive correlation

Cortisol resistance to suppression by 0.5 mg of dexamethasone given at 11 p.m. was studied in 30 normal subjects, 17 to 78 years of age. Serum cortisol concentrations were determined by radioimmunoassay. A strong positive correlation was found between age and cortisol concentrations 9 hours after dexamethasone administration. The data suggest that aging, per se, might contribute to the increased cortisol resistance to suppression by dexamethasone reported in depression and dementia.

Failure of single-dose lecithin to alter aspects of central cholinergic activity in Alzheimer's disease

The effect of a single dose (15 g/70 kg) of lecithin (95% phosphatidylcholine) on several measures of central cholinergic activity (memory, cortisol, prolactin, pulse, blood pressure) was assessed in individuals with Alzheimer's disease. In contrast to the reported effects of physostigmine, a cholinesterase inhibitor, lecithin had no effect on these parameters, despite significant increases in plasma and erythrocyte choline.

Elevation of RBC glycine and choline levels in geriatric patients treated with lithium

During 6 weeks of lithium treatment, the RBC glycine and choline levels of five cognitively impaired geriatric subjects without affective disorders increased significantly and correlated with RBC and plasma lithium levels. The subjects' cognitive processes did not improve.