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R C Green

Publications and source records attributed to R C Green.

At least 37 records · Page 2Linked to original sources
PubMed1997

Early detection of Alzheimer disease: methods, markers, and misgivings.

There is at present no reliable predictive test for most forms of Alzheimer disease (AD). Although some information about future risk for disease is available in theory through ApoE genotyping, it is of limited accuracy and utility. Once neuroprotective treatments are available for AD, reliable early detection will become a key component of the treatment strategy. We recently conducted a pilot survey eliciting attitudes and beliefs toward an unspecified and hypothetical predictive test for AD. The survey was completed by a convenience sample of 176 individuals, aged 22-77, which was 75% female, 30% African-American, and of which 33% had a family member with AD. The survey revealed that 69% of this sample would elect to obtain predictive testing for AD if the test were 100% accurate. Individuals were more likely to desire predictive testing if they had an a priori belief that they would develop AD (p = 0.0001), had a lower educational level (p = 0.003), were worried that they would develop AD (p = 0.02), had a self-defined history of depression (p = 0.04), and had a family member with AD (p = 0.04). However, the desire for predictive testing was not significantly associated with age, gender, ethnicity, or income. The desire to obtain predictive testing for AD decreased as the assumed accuracy of the hypothetical test decreased. A better short-term strategy for early detection of AD may be computer-based neuropsychological screening of at-risk (older aged) individuals to identify very early cognitive impairment. Individuals identified in this manner could be referred for diagnostic evaluation and early cases of AD could be identified and treated. A new self-administered, touch-screen, computer-based, neuropsychological screening instrument called Neurobehavioral Evaluation System-3 is described, which may facilitate this type of screening.

Adult↗
PubMed1997

Assessment of CSF levels of tau protein in mildly demented patients with Alzheimer's disease.

CSF levels of tau protein are increased in many patients with Alzheimer's disease (AD). Studies disagree on whether the increase is found in moderate or severe AD to a greater extent than in mild AD, and in two reports there was an inverse correlation between tau levels and cognitive scores. To readdress this question, we measured CSF tau in a group of mildly impaired patients with AD (Mini-Mental State Examination [MMSE] scores > or =20/30) and compared their tau levels with those in age-comparable normal and neurologic controls. We found that the mean level of CSF tau was significantly increased in the AD group compared with the controls, and 29 of 36 patients with AD had levels that exceeded a cutoff determined in a previous study. CSF tau levels did not correlate with MMSE scores. These findings and those of previous studies show that elevated CSF tau levels are found in most patients with AD, occur early in the course of dementia, and may be useful in supporting the diagnosis of AD.

Aged↗
PubMed1996

Event-related potential P3 change in mild Parkinson's disease.

The purpose was to determine if unmedicated, mildly affected patients with Parkinson's disease exhibited abnormality in the P3 component of the event-related potential, and whether such abnormality differed between younger and older patients. The study evaluated 10 younger (mean age = 43.7 years) and 10 older (mean age = 64.4 years) unmedicated patient volunteers diagnosed with idiopathic PD during the past 4 years and equal numbers of age-, gender-, and education-matched controls. The auditory oddball P3 was recorded, and P3 peak amplitude, peak latency, and the component score derived from principal components analysis were analysed. Neuropsychological measures focusing on frontal lobe and memory function were obtained. Although patients did not show neuropsychological deficits, they had significantly enlarged P3 amplitude measured at Cz (p < 0.01) or Pz (p < 0.01). The P3 amplitude abnormality among patients was not affected by age. Patient P3 latency was not prolonged. The results indicate that P3 amplitude may more sensitive than neuropsychological measures for detecting subtle brain dysfunction occurring early in PD. This measure has possible utility for detecting and tracking early disease. It is hypothesized that enlarged P3 amplitude reflects abnormality in use of attentional resources to compensate for brain dysfunction.

Adult↗
PubMed1996

Pupillary response to tropicamide in patients with Alzheimer disease.

PURPOSE: To determine whether pupillary responses to dilute tropicamide could be used as a diagnostic test for Alzheimer disease (AD). The authors also investigated whether concurrent use of an oral acetylcholinesterase inhibitor (tacrine) alters the pupillary response to dilute tropicamide in patients with AD, and whether pupillary responses to dilute tropicamide differ in young versus older control subjects. METHODS: Pupillary diameter and area of both eyes were measured in light and darkness, at 10-minute intervals for 40 minutes after random instillation of 0.01% tropicamide to one eye. Four groups of subjects were studied: 9 patients with AD, 10 who were treated with tacrine, 11 older control subjects, and 10 young control subjects. RESULTS: Mean change in anisocoria was not significantly different among groups at any of the measurement time points. Mean percent change in diameter of the treated eyes showed a trend toward faster maximum dilatation in the AD groups, but change in pupillary measurements did not identify individuals with AD. CONCLUSION: Pupillary response to dilute tropicamide did not effectively distinguish individual patients with AD from young or older control subjects.

Adult↗
PubMed1996

A treatment and withdrawal trial of besipirdine in Alzheimer disease.

Besipirdine hydrochloride (HP 749) is an indole-substituted analog of 4-aminopyridine. Besipirdine enhances both cholinergic and adrenergic neurotransmission in the central nervous system. The present study examined the efficacy and tolerability of two doses of besipirdine (5 and 20 mg b.i.d.) in 275 patients with Alzheimer disease during 3 months of treatment and for 3 months after withdrawal of treatment. Assessment after withdrawal of treatment was used in an effort to distinguish persistent efficacy attributable to a neuroprotective mechanism from reversible symptomatic efficacy. Besipirdine was generally well tolerated. The level of performance on the cognitive subscale of the Alzheimer Disease Assessment Scale (ADAS-Cog) was sustained during 3 months of treatment with besipirdine, whereas some deterioration in the performance of patients treated with placebo was observed over the same period. The small difference between active and placebo treatment groups approached, but did not reach statistical significance in the primary intent-to-treat analysis (p = 0.067); analysis of patients who completed all assessments was supportive (p = 0.031). Global ratings using the Clinician Interview-Based Impression of Change did not detect a besipirdine treatment benefit, possibly because of an adverse effect on mood and behavior in some patients. A high ratio of adrenergic to cholinergic potency may have resulted in the adverse effects of besipirdine and hence its failure to support the hypothesis that multiple neurotransmitter treatment may be more efficacious than monotherapy. The efficacy apparent on the ADAS-Cog after 3 months of treatment did not persist 3 months after withdrawal of treatment, suggesting that the benefit was symptomatic. This study provides a practical example of the use of treatment withdrawal assessment to distinguish neuroprotective from symptomatic efficacy.

Aged↗
PubMed1996

Risk of dementia among relatives of Alzheimer's disease patients in the MIRAGE study: What is in store for the oldest old?

Despite recent advances in the molecular genetics of Alzheimer's disease (AD), several fundamental questions concerning risk of illness are unresolved, namely, if Mendelian factors account for the incidence of the disease, and if AD is an inevitable consequence of the aging process. This study was designed to address these issues and other aspects of familial aggregation of the disorder. A consecutive sample of 1,694 patients who met criteria for a diagnosis of probable or definite AD were ascertained in 13 centers participating in the Multi-Institutional Research in Alzheimer Genetic Epidemiology (MIRAGE) project. Lifetime risk and age at onset of AD among various strata of 12,971 first-degree relatives was estimated using survival analysis procedures. The lifetime risk of AD in first-degree relatives was 39.0% +/- 2.1% by age 96 years. Age-specific risk of AD declined after age 90 and the data set included 61 apparently unaffected persons who survived to age 96 without becoming demented. Female relatives had a higher risk of AD than male relatives at all ages. By age 80, children of conjugal AD couples had a cumulative risk of 54%, 1.5 times greater than the sum of the risks to children having affected mothers or fathers, and nearly 5 times greater than the risk to children having normal parents. Children of affected fathers had a cumulative risk that was 1.4 times the corresponding risk to children of affected mothers. Risk assessment in early-onset and late-onset families, using various strategies for determining the age cut-off, yielded contradictory results. These data suggest the following: (1) the lifetime risk among relatives does not support a simple autosomal dominant inheritance pattern of disease; (2) women are innately more susceptible to AD than men; (3) the proportion of hereditary cases may be higher in men than women; (4) distinction between early- onset and late-onset forms of AD has little meaning in the absence of a biological marker; (5) the risk of AD decreases after age 90; and (6) AD therefore may not be an inevitable concomitant of the aging process, a conclusion that has profound implications for basic and applied AD research. The age- and sex-specific lifetime risks derived from this study are sufficiently robust to be a reliable source of information for counseling relatives of AD patients.

Age Factors↗
PubMed1996

Prosody impairment and associated affective and behavioral disturbances in Alzheimer's disease.

We examined the ability to produce, repeat, and comprehend emotional prosody in 20 patients with Alzheimer's disease (AD) and in 11 elderly normal control subjects. In addition, caregivers of AD patients completed affective and behavioral measures with reference to the patient. Relative to control subjects, comprehension of emotional prosody was marginally impaired in mildly demented AD patients, whereas production, comprehension, and repetition of emotional prosody were significantly impaired in moderately demented AD patients. The moderately demented patients performed significantly poorer than the mildly demented patients on the production and repetition tasks. In contrast, there was no significance difference between the two groups on the prosody comprehension task. Additional analyses revealed an inverse relationship between the ability to correctly produce and repeat emotional prosody and the frequency of agitated behaviors and depressive symptomatology in moderately demented patients. This latter findings suggests that the inability to communicate emotional message is associated with disturbances in mood and behavior in AD patients. Implications for the management of disruptive behavior in agitated and aprosodic AD patients include the development of caregiver sensitivity to unexpressed emotion and caregiver assistance with emotional expression.

Aged↗
PubMed1996

Evidence for major gene inheritance of Alzheimer disease in families of patients with and without apolipoprotein E epsilon 4.

Apolipoprotein E (APOE) genotype is the single most important determinant to the common form of Alzheimer disease (AD) yet identified. Several studies show that family history of AD is not entirely accounted for by APOE genotype. Also, there is evidence for an interaction between APOE genotype and gender. We carried out a complex segregation analysis in 636 nuclear families of consecutively ascertained and rigorously diagnosed probands in the Multi-Institutional Research in Alzheimer Genetic Epidemiology study in order to derive models of disease transmission which account for the influences of APOE genotype of the proband and gender. In the total group of families, models postulating sporadic occurrence, no major gene effect, random environmental transmission, and Mendelian inheritance were rejected. Transmission of AD in families of probands with at least one epsilon 4 allele best fit a dominant model. Moreover, single gene inheritance best explained clustering of the disorder in families of probands lacking epsilon 4, but a more complex genetic model or multiple genetic models may ultimately account for risk in this group of families. Our results also suggest that susceptibility to AD differs between men and women regardless of the proband's APOE status. Assuming a dominant model, AD appears to be completely penetrant in women, whereas only 62%-65% of men with predisposing genotypes develop AD. However, parameter estimates from the arbitrary major gene model suggests that AD is expressed dominantly in women and additively in men. These observations, taken together with epidemiologic data, are consistent with the hypothesis of an interaction between genes and other biological factors affecting disease susceptibility.

Adult↗
PubMed1995

Apolipoprotein E genotype in patients with Alzheimer's disease: implications for the risk of dementia among relatives.

Numerous studies have shown that the risk of Alzheimer's disease (AD) is associated with the dose of the epsilon 4 allele of apolipoprotein E (ApoE). However, more than one third of AD patients lack epsilon 4 and many persons having epsilon 4 survive cognitively intact to old age. We evaluated the lifetime risk of disease in 3,999 first-degree relatives of 549 probands who met the criteria for probable or definite AD and whose ApoE genotypes were known. ApoE genotypes for relatives were not determined. After age 65 the risk among relatives was proportional, as much as 7 to 10% at age 85, to the number of epsilon 4 alleles present in the proband. Risks to relatives of ApoE 2/2 and 2/3 probands were nearly identical at all ages to risks for relatives of ApoE 3/3 probands. The expected proportion of relatives having at least one epsilon 4 allele was calculated for each genotype group based on the distribution of parents, sibs, and offspring in the sample. Among relatives in the ApoE 3/3 group, the lifetime risk for AD by age 90 was three times greater than the expected proportion of epsilon 4 carriers, suggesting that factors other than ApoE contribute to AD susceptibility. Furthermore, the 44% risk of AD by age 93 among relatives of ApoE 4/4 probands indicates that as many as 50% of people having at least one epsilon 4 allele do not develop AD. We also found that among male relatives, risk of AD in the ApoE 3/4 group was similar to that for the ApoE 3/3 group but significantly less than the risk for the ApoE 4/4 group. In contrast, among female relatives the risk for the ApoE 3/4 group was nearly twice that for the ApoE 3/3 group and identical to the risk for the ApoE 4/4 group. These findings are consistent with a sex-modification effect of the E4 isoform on disease susceptibility.

Age of Onset↗
PubMed1995

Slowly progressive apraxia in Alzheimer's disease.

Slowly progressive apraxia due to Alzheimer's disease was encountered in a 66 year old, right handed man whose initial impairments included coordinated movements of the left hand and some features of the alien hand syndrome. Over four years, the patient developed progressively worsening deficits of memory and language. A biopsy of his right temporal lobe showed numerous plaques and neurofibrillary tangles. Pronounced right parietal lobe hypoperfusion on serial SPECT suggests involvement of this region in contralateral praxis.

Aged↗
PubMed1995

Validity of the Mattis Dementia Rating Scale for detection of cognitive impairment in the elderly.

The validity of the Mattis Dementia Rating Scale (DRS) for detecting neuropsychological impairment was evaluated in 22 elderly patients with mild cognitive impairment and 48 rigorously screened control subjects. A cutoff score was identified that correctly classified 95% of patients and 100% of control subjects. Results of this preliminary study suggest that the DRS may prove useful in screening for mild cognitive impairment in elderly populations. Further validation with a representative elderly sample is needed to establish screening value in primary care or community populations.

Aged↗
PubMed1995

Fellowship programs in behavioral neurology.

We sent a behavioral neurology fellowship questionnaire to each of the training directors of 160 neurology residency programs throughout the world, seeking information about programs offering advanced training in behavioral neurology (or similar fellowships in cognitive neurology, neurobehavior, or cognitive neuroscience). Response rate was 100%. Thirty-four respondents reported active fellowship programs in behavioral neurology, and 28 additional respondents indicated that a behavioral neurology fellowship was planned. Nine of the 34 programs (26.5%) defined themselves as exclusively or predominantly concerned with dementia and age-related neurobehavioral disorders. Directors of the 34 active fellowship programs estimated that their combined programs had graduated 199 fellows and were currently training fifty. Most fellowships concentrated on outpatient clinical training, with teaching required by 78.1% and research required by 81.8%. Specialty certification for behavioral neurology was favored by over 75% of behavioral neurology fellowship training directors but by only 30% of training directors in residency programs without behavioral neurology fellowships. Behavioral neurology training programs have grown dramatically in response to an increased recognition of the academic interest in and the clinical needs for these services.

Behavioral Medicine↗
PubMed1994

Non-peptidic inhibitors of human leukocyte elastase. 1. The design and synthesis of pyridone-containing inhibitors.

Human leukocyte elastase (HLE) is a serine protease produced by neutrophils that has been implicated in diseases such as emphysema and cystic fibrosis. An HLE inhibitor may have therapeutic value in these diseases. An active site model of HLE bound to a tripeptidic trifluoromethyl ketone (TFMK) inhibitor, 2, was created from X-ray structures of HLE and porcine pancreatic elastase. Analysis of the model indicated a preferred binding conformation for the tripeptide and potentially important interactions between it and the enzyme. This information was used to aid in the design of a series of novel, pyridone-containing, non-peptidic HLE inhibitors such as 2-[3-[[(benzyloxy)carbonyl]amino]-2-oxo- 1,2-dihydro-1-pyridyl]-N-(3,3,3-trifluoro-1-isopropyl-2-oxopropyl)ace tam ide (5b) (Ki = 280 +/- 78 nM). Inspection of the active site model suggested that a benzyl substituent at the 5-position of the pyridone ring might improve potency by forming a lipophilic interaction with the enzyme S2 pocket. Synthesis and biological evaluation of a series of 5-benzylpyridone TFMKs provided evidence for this proposition. Further analysis of the model indicated that substitution on the 3-amino group of the pyridone ring with a hydrogen bond acceptor could potentially lead to interactions with the NH atoms of glycine-218 and/or -219. The oxalate derivative 2-[5-benzyl- 3-(carboxycarbonyl)-2-oxo-1,2-dihydro-1-pyridyl]-N-(3,3,3-trifl uor o-1- isopropyl-2-oxopropyl)acetamide (5v) was synthesized and found to have a Ki of 48 +/- 9 nM. Unfortunately, none of the compounds tested was active in an in vivo model of HLE-induced lung injury when dosed orally.

Amino Acid Sequence↗
PubMed1994

Screening for cognitive impairment in older individuals. Validation study of a computer-based test.

OBJECTIVE: This study examined the validity of a computer-based cognitive test that was recently designed to screen the elderly for cognitive impairment. DESIGN: Criterion-related validity was examined by comparing test scores of impaired patients and normal control subjects. Construct-related validity was computed through correlations between computer-based subtests and related conventional neuropsychological subtests. SETTING: University center for memory disorders. PARTICIPANTS: Fifty-two patients with mild cognitive impairment by strict clinical criteria and 50 unimpaired, age- and education-matched control subjects. Control subjects were rigorously screened by neurological, neuropsychological, imaging, and electrophysiological criteria to identify and exclude individuals with occult abnormalities. RESULTS: Using a cut-off total score of 126, this computer-based instrument had a sensitivity of 0.83 and a specificity of 0.96. Using a prevalence estimate of 10%, predictive values, positive and negative, were 0.70 and 0.96, respectively. Computer-based subtests correlated significantly with conventional neuropsychological tests measuring similar cognitive domains. Thirteen (17.8%) of 73 volunteers with normal medical histories were excluded from the control group, with unsuspected abnormalities on standard neuropsychological tests, electroencephalograms, or magnetic resonance imaging scans. CONCLUSIONS: Computer-based testing is a valid screening methodology for the detection of mild cognitive impairment in the elderly, although this particular test has important limitations. Broader applications of computer-based testing will require extensive population-based validation. Future studies should recognize that normal control subjects without a history of disease who are typically used in validation studies may have a high incidence of unsuspected abnormalities on neurodiagnostic studies.

Aged↗