L-deprenyl in Alzheimer's disease: cognitive and behavioral effects

BACKGROUND

Short-term studies of L-deprenyl in Alzheimer's disease (AD) suggest a beneficial effect, whereas longer-term studies are less convincing. Accordingly, we undertook a 6-month, randomized, double-blind, placebo-controlled clinical trial to assess the potential benefit of L-deprenyl in AD.

METHODS

Sixty subjects were assigned to L-deprenyl (10 mg daily) or placebo. After 4 weeks of single-blind placebo, 51 subjects entered the double-blind phase. The Brief Psychiatric Rating Scale (BPRS) was the primary outcome measure. Secondary outcome measures were the Mini-Mental State Examination, Global Deterioration Scale, Alzheimer's Disease Assessment Scale (noncognitive), Cornell Scale for Depression in Dementia, Buschke Selective Reminding Test (BSRT), Relative's Assessment of Global Symptomatology-Elderly (RAGS-E), Controlled Oral Word Association Test, and Modified Continuous Performance Test. In addition, several exploratory tasks were included for future hypothesis testing.

RESULTS

We found no significant differences between the L-deprenyl and placebo groups on the primary or secondary measures. However, several measures appeared to be sensitive to change over time, including the total score on the BPRS and some of its components as well as parts of the BSRT and the RAGS-E.

CONCLUSION

Oral L-deprenyl provides no detectable benefit on general behavior, neuropsychiatric symptoms, or cognitive function in AD after 6 months of treatment. Protocols for future drug studies should utilize measures that are sensitive to change over time such as the BPRS.

Clustering and switching on verbal fluency tests in Alzheimer's and Parkinson's disease

Two components of verbal fluency performance--clustering (i.e., generating words within subcategories) and switching (i.e., shifting between subcategories)--were examined in patients with dementia of the Alzheimer type (DAT), patients with dementia with Parkinson's disease (DPD), nondemented patients with Parkinson's disease (NPD), and demographically matched controls. The DAT and DPD groups were impaired in the number of words generated on both phonemic and semantic fluency. The DAT group produced smaller clusters on both tasks and switched less often on semantic fluency than controls. The DPD group switched less often on both tasks and produced smaller clusters on phonemic fluency than controls. The NPD group was not impaired on any fluency variable. Thus, the total number of words generated on phonemic and semantic fluency did not discriminate the dementia groups from their respective control groups, but measures of clustering and switching did. This differential pattern of performance provides evidence for the potential usefulness of measures of switching and clustering in the assessment of dementia.

Orbitofrontal function, object alternation and perseveration

Object alternation (OA) is a well-established measure of perseveration and orbitofrontal function in non-human primates. Although several studies have used OA to examine orbitofrontal system dysfunction in humans with neurological and psychiatric disease, this task itself has not been validated as a bona fide measure of frontal dysfunction in humans. To address this issue, six patients with bilateral frontal lobe lesions documented by computerized tomography (CT) or magnetic resonance imaging (MRI) and 15 healthy controls were given OA, as well as other measures of frontal system dysfunction, delayed alternation (DA), delayed response (DR), and the Wisconsin Card Sorting Test (WCST). The CT and MRI scans were interpreted blindly. The patients with bilateral frontal lesions were significantly impaired on OA, DA, DR and the WCST. Analyses of the CT/MRI lesions suggest that the neuroanatomical regions involved in the deficits on OA include Brodmann areas 10, 24, 32 and 47, as well as possibly 11, and that OA is a sensitive measure of ventrolateral-orbitofrontal and medial frontal dysfunction in humans. Our findings lend further support for the use of experimental paradigms adopted from animal models to study the functional neuroanatomy and neuropsychological mechanisms underlying cognitive functions in humans with neurological and psychiatric disease.

Midazolam versus propofol for long-term sedation in the ICU: a randomized prospective comparison

OBJECTIVE

To compare the efficacy, safety, and cost of midazolam and propofol in prolonged sedation of critically ill patients.

DESIGN

Randomized, prospective study.

SETTING

General intensive care unit (ICU) in a 1100-bed teaching hospital.

PATIENTS

67 critically ill, mechanically ventilated patients.

INTERVENTIONS

Patients were invasively monitored and mechanically ventilated. A loading dose [midazolam 0.11 +/- 0.02 (SEM) mg.kg-1, propofol 1.3 +/- 0.2 mg.kg-1] was administered, followed by continuous infusion, titrated to achieve a predetermined sedation score. Sedation was continued as long as clinically indicated.

MEASUREMENTS AND RESULTS

Mean duration of sedation was 141 and 99 h (NS) for midazolam and propofol, respectively, at mean hourly doses of 0.070 +/- 0.003 mg.kg-1 midazolam and 1.80 +/- 0.08 mg.kg-1 propofol. Overall, 68% of propofol patients versus 31% of midazolam (p < 0.001) patients had a > 20% decrease in systolic blood pressure after the loading dose, and 26 versus 45% (p < 0.01) showed a 25% decrease in spontaneous minute volume. Propofol required more daily dose adjustments (2.1 +/- 0.1 vs 1.4 +/- 0.1, p < 0.001). Nurse-rated quality of sedation with midazolam was higher (8.2 +/- 0.1 vs 7.3 +/- 0.1 on a 10-cm visual analog scale, p < 0.001). Resumption of spontaneous respiration was equally rapid. Recovery was faster after propofol (p < 0.02), albeit with a higher degree of agitation. Amnesia was evident in all midazolam patients but in only a third of propofol patients. The cost of propofol was 4-5 times higher.

CONCLUSIONS

Both drugs afforded reliable, safe, and controllable long-term sedation in ICU patients and rapid weaning from mechanical ventilation. Midazolam depressed respiration, allowed better maintenance of sedation, and yielded complete amnesia at a lower cost, while propofol caused more cardiovascular depression during induction.

Building communities that promote successful aging

Despite the fact that, in a few years, a fifth of the US population will be older than 65 years and people will be living a third of their lives after retirement, we have developed few avenues that would permit older adults to play meaningful roles as they age and few institutions to harness the experience that older adults could contribute to society. In fact, older adults constitute this country's only increasing natural resource--and the least used one. In this article we consider the rationale for developing institutions that harness the abilities and time of older adults, rather than focusing solely on their needs. Such an approach would decrease the structural lag between a social concept of retirement as unproductive leisure and an aging population that is larger, healthier, and with a need for more productive opportunities. Gerontologically designed opportunities for contribution on a large social scale could well provide a national approach to primary prevention to maintain health and function in older adults.

Polycythemia secondary to focal nodular hyperplasia

An otherwise healthy 14-year-old girl presented with polycythemia and elevated serum erythropoietin. A lesion was identified in the liver by ultrasound scan and computerized axial tomography. The pathology findings of the mass excised by hepatic segmentectomy showed focal nodular hyperplasia that stained positively for erythropoietin by immunohistochemistry. Resection resulted in a cure of the polycythemia with serum erythropoietin, hemoglobin, and hematocrit returning to normal range in subsequent follow-up. To our knowledge, this is the first report of focal nodular hyperplasia resulting in secondary polycythemia.

Orienting of visual attention in Alzheimer's disease: its implication in favor of the interhemispheric balance

Visual attention in dementia of Alzheimer's disease (AD) has not been investigated as extensively as memory or language. The aim of this research was to study the orienting of attention in patients with AD (which temporo-parietal areas are primarily affected) compared with patients with Parkinson-Dementia, Parkinson's disease, and normal controls, using the Posner paradigm. Subjects were instructed to respond by pressing a response key after the appearance of a target at the same location (valid trial) or at the opposite location (invalid trial) indicated by a central cue (arrow). According to the experimental procedure developed by Posner, it has been hypothesized that parietal lobes are involved in "disengagement operation" (when attention has to move from one location to another in the controlateral field). Results showed no differences between AD and the other groups and between left and right hemifield. In conclusion, the authors did not find any sign of difficulty with disengagement, and results are discussed in terms of Kinsbourne's interpretation of a balance between hemispheres.

Breakdown of cross-modal function in dementia

To evaluate the possibility that specific language abnormalities in dementia are related to impaired cross-modal ability, the authors studied patients with Alzheimer's disease (which is characterized by a generalized language breakdown or aphasia) and patients with Parkinson's disease and dementia (a disorder associated more with selective deficits in naming than with aphasia). Both groups were initially equated for severity of dementia. Compared with nondemented patients with Parkinson's disease and age-equivalent healthy controls, patients with Alzheimer's disease and Parkinson's disease with dementia showed significant deficits in cross-modal ability. Moreover, the cross-modal deficits were significantly associated with object-naming ability. Results support the concept that language capacity and cross-modal functions are interrelated.

Mutations in the granulocyte colony-stimulating factor receptor gene in patients with severe congenital neutropenia

Previously, nonsense mutations in the gene encoding the granulocyte colony-stimulating factor receptor (G-CSF-R) have been described in three patients with severe congenital neutropenia (SCN) (Proc Natl Acad Sci USA 1994; 91: 4480; New Engl J Med 1995; 333: 487). The mutations resulted in the truncation of the carboxy-terminal region of G-CSF-R essential for transduction of maturation signals. Two of these patients developed acute myeloblastic leukemia (AML). We present the results of a search among 20 additional cases of congenital neutropenia (CN) and SCN for the presence of mutations in the cytoplasmic domain of G-CSF-R. This series includes patients with familial and nonfamilial forms of CN and SCN. Mutations in the G-CSF-R gene were found in two new SCN cases. These mutations were nonsense mutations, located in the same cytoplasmic region of G-CSF-R as those found earlier, resulting in the truncation of the C-terminus. Both of these patients developed AML. None of the other patients showed clinical symptoms or cytogenetic features indicative of AML or progression to leukemia. The analysis in this extended series of patients thus has revealed five SCN cases with G-CSF-R mutations, four of whom developed AML. These results add support to the notion that mutations in the G-CSF-R gene, affecting the maturation signaling function of the receptor, define a distinct subgroup of SCN with increased susceptibilty to AML.

A full genome search in multiple sclerosis

The aetiology of multiple sclerosis (MS) is uncertain. There is strong circumstantial evidence to indicate it is an autoimmune complex trait. Risks for first degree relatives are increased some 20 fold over the general population. Twin studies have shown monozygotic concordance rates of 25-30% compared to 4% for dizygotic twins and siblings. Studies of adoptees and half sibs show that familial risk is determined by genes, but environmental factors strongly influence observed geographic differences. Studies of candidate genes have been largely unrewarding. We report a genome search using 257 microsatellite markers with average spacing of 15.2 cM in 100 sibling pairs (Table 1, data set 1 - DS1). A locus of lambda>3 was excluded from 88% of the genome. Five loci with maximum lod scores (MLS) of >1 were identified on chromosomes 2, 3, 5, 11 and X. Two additional data sets containing 44 (Table 1, DS2) and 78 sib pairs (Table 1, DS3) respectively, were used to further evaluate the HLA region on 6p21 and a locus on chromosome 5 with an MLS of 4.24. Markers within 6p21 gave MLS of 0.65 (non-significant, NS). However, D6S461, just outside the HLA region, showed significant evidence for linkage disequilibrium by the transmission disequilibrium test (TDT), in all three data sets (for DS1 chi2 = 10.8, adjusted P < 0.01)(DS2 and DS3 chi2 = 10.9, P < 0.0005), suggesting a modest susceptibility locus in this region. On chromosome 5p results from all three data sets (222 sib pairs) yielded a multipoint MLS of 1.6. The results support genetic epidemiological evidence that several genes interact epistatically to determine heritable susceptibility.

Subcortical dementia: a neurobehavioral approach

The subcortical dementias are a heterogeneous group of disorders in which the predominant pathological lesions occur in subcortical structures such as basal ganglia, brainstem nuclei, and the cerebellum. When the cerebral cortex is involved, the lesions are most often in the frontal lobes. These pathologic lesions are associated with cognitive changes that include bradyphrenia, personality change (apathy, depression, irritability), memory impairment, and impaired manipulation of acquired knowledge (calculation, abstraction). Aphasia, apraxia, and agnosia are commonly seen in the cortical dementias, but are absent in the subcortical dementias. Progress in research on the anatomy and connectivity of cortical-subcortical structures has led to refinement in our understanding of the cortical dementias. Despite the connectivity between the cortical and subcortical structures, patterns of cognitive impairment in subcortical dementias remain distinct.

Qualitative and quantitative contributions of the T cell receptor zeta chain to mature T cell apoptosis

Engagement of the T cell receptor (TCR) of mature T lymphocytes can lead either to activation/proliferation responses or programmed cell death. To understand the molecular regulation of these two fundamentally different outcomes of TCR signaling, we investigated the participation of various components of the TCR-CD3 complex. We found that the TCR-zeta chain, while not absolutely required, was especially effective at promoting mature T cell apoptosis compared with the CD3 epsilon, gamma, or delta chains. We also carried out mutagenesis to address the role of the immunoreceptor tyrosine-based activation motifs (ITAMs) that are the principal signaling components found three times in the TCR-zeta chain and once in each of the CD3 epsilon, gamma, or delta chains. We found that the ability of the TCR-zeta chain to promote apoptosis results both from a quantitative effect of the presence of multiple ITAMs as well as qualitatively different contributions made by individual ITAMs. Apoptosis induced by single chain chimeras revealed that the first zeta ITAM stimulated greater apoptosis than the third zeta ITAM, and the second zeta ITAM was unable to trigger apoptosis. Because microheterogeneity in the amino acid sequence of the various ITAM motifs found in the TCR-zeta and CD3 chains predicts interactions with distinct src-homology-2-domain signaling proteins, our results suggest the possibility that individual ITAM motifs might play unique roles in TCR responses by engaging specific signaling pathways.

Inhibition of acute lymphoblastic leukaemia by a Jak-2 inhibitor

Acute lymphoblastic leukaemia (ALL) is the most common cancer of childhood. Despite the progress achieved in its treatment, 20% of cases relapse and no longer respond to chemotherapy. The most common phenotype of ALL cells share surface antigens with very early precursors of B cells and are therefore believed to originate from this lineage. Characterization of the growth requirement of ALL cells indicated that they were dependent on various cytokines, suggesting paracrine and/or autocrine growth regulation. Because many cytokines induce tyrosine phosphorylation in lymphoid progenitor cells, and constitutive tyrosine phosphorylation is commonly observed in B-lineage leukaemias, attempts have been made to develop protein tyrosine kinase (PTK) blockers of leukaemia cell growth. Here we show that leukaemic cells from patients in relapse have constitutively activated Jak-2 PTK. Inhibition of Jak-2 activity by a specific tyrosine kinase blocker, AG-490, selectively blocks leukaemic cell growth in vitro and in vivo by inducing programmed cell death, with no deleterious effect on normal haematopoiesis.

Usefulness of follow-up regional cerebral blood flow measurements by single-photon emission computed tomography in the differential diagnosis of dementia

The aim of this study was to evaluate whether follow-up measurements of regional cerebral blood flow (rCBF) by single-photon emission computed tomography (SPECT) provide additional information in the differential diagnosis of dementia. Thirty-six patients (70 +/- 14 yr) with suspected dementia who had two technetium 99m-hexamethylpropyleneamineoxime SPECT scans over 18 +/- 7 months were included in this retrospective study. The patients comprised three groups based on the final clinical diagnosis: (1) neurodegenerative disorder (NDD) including Alzheimer's disease (AD) (n = 13), frontotemporal lobe dementia (n = 2), progressive supranuclear palsy (n = 1), and mixed dementia (AD plus multiinfarct dementia [MID]) (n = 3); (2) MID (n = 8); and (3) psychiatric disorders (depression [n = 7], psychosis [n = 1], and anxiety [n = 1]). Blinded to the clinical diagnosis and using visual analysis, the nuclear medicine physicians compared the second scan with the first scan for each patient to characterize temporal changes in rCBF. SPECT findings were categorized into three patterns of rCBF change: worsened, improved, and unchanged. Of the worsened rCBF group, 17 (85%) belonged to the NDD group whereas 2 (10%) and 1 (5%) belonged to the MID and psychiatric disorders groups, respectively. All 5 (100%) of the improved rCBF patients belonged to the psychiatric disorders group. Thus, worsening of rCBF favors the diagnosis of NDD whereas improvement in rCBF may mitigate against the diagnosis of NDD or MID. Follow-up rCBF measurements by SPECT thus provided additional information on the possible cause of dementia. A prospective study to further evaluate the usefulness of follow-up rCBF measurements by SPECT appears warranted.

Monosomy 7 and activating RAS mutations accompany malignant transformation in patients with congenital neutropenia

Individuals with severe forms of congenital neutropenia suffer from recurrent infections. The therapeutic use of recombinant human granulocyte colony-stimulating factor (rhG-CSF) to increase the neutrophil count is associated with fewer infections and an improved quality of life. However, the long-term effects of this new therapy are largely unknown. In particular, it is unclear if myeloid leukemia, a known complication of some forms of congenital neutropenia, will occur with increased frequency among patients who receive long-term treatment with hematopoietic growth factors. We report 13 patients with congenital disorders of myelopoiesis who developed leukemic transformation with either myelodysplastic syndrome (MDS) or acute myelogenous leukemia (AML) and 1 who acquired a clonal cytogenetic abnormality without evidence of MDS or AML while receiving rhG-CSF. The bone marrows of 10 patients showed monosomy 7 and 5 had activating RAS mutations. These abnormalities were not detected in pretreatment bone marrows and cessation of rhG-CSF was not associated with either clinical improvement or cytogenetic remission. We conclude that patients with severe forms of congenital neutropenia are at relatively high risk of developing MDS and AML. The occurrence of monosomy 7 and RAS mutations in these cases suggests that the myeloid progenitors of some patients are genetically predisposed to malignant transformation. The relationship between therapeutic rhG-CSF and leukemogenesis in patients with severe chronic neutropenia is unclear.

Failure to detect missense mutations in the S182 gene in a series of late-onset Alzheimer's disease cases

The possibility of an interaction of multiple genes has been speculated in pathogenesis of Alzheimer's disease (AD). Because we have recently cloned a novel gene S182 bearing five different missense mutations which segregate with early-onset familial AD, we sought the frequency of these mutations in familial and sporadic late-onset AD to clarify the incidence of these mutations in the disease. The current study showed lack of these mutations in 118 independent subjects affected with late-onset Alzheimer's disease.

Quality control of storage phosphor digital radiography systems

Quality control (QC) of storage phosphor devices is important in assuring that the image information entered into an Image management and communication (IMAC) system is sufficient for diagnosis. QC of storage phosphor digital radiography systems is complex because of the self-corrective nature of the image-processing software used in these machines. Currently, one must produce hard copy to perform adequate QC. Inspection of images with reject analysis and inspection of cassettes and imaging plates has helped us in our QC program. For those QC tests using control limits, the appropriate settings for these limits are unknown. Starting approximations are given. Recommended tests are described.

Digital radiography of the musculoskeletal system: the optimal image

Digital radiography (DR) is replacing screen-film (SF) radiography for musculoskeletal examinations in our institution. After an iterative process of image quality improvement, our DR images are now preferred to SF images, and we have detailed our current optimized settings for the Fuji 9000 (Fuji Medical Systems, Tokyo, Japan). DR offers the advantages of improved contrast resolution, adjustable image contrast, the ability to reprocess the image, and the ease of transferring the image to an image management and communication system (IMAC).

Autocrine feedback death and the regulation of mature T lymphocyte antigen responses

Antigen-induced T cell death is an important regulatory mechanism in the peripheral immune system. Evidence suggests that this process depends on T cell growth-inducing lymphokines such as IL-2 and occurs in proportion to the degree of T cell receptor occupancy. Strong T cell receptor stimulation leads to the synthesis of death molecules such as Fas ligand and tumor necrosis factor that cause T cell suicide. We propose that T cell death under these circumstances is the culmination of a feedback control mechanism termed propriocidal regulation or autocrine feedback death that regulates the expansion of specific T cell clones under conditions of high lymphokine and antigen load. In a quasi-stochastic system such as the antigen receptor repertoire, feedback information may be essential for the appropriate regulation of peripheral immune responses. Our understanding of this feedback mechanism affords a means to manipulate antigen-specific T cell death in vivo. The application of this approach to the therapy of T cell-medicated immunological diseases is discussed.

Neuropsychological test performance in patients with dominantly inherited spinocerebellar ataxia: relationship to ataxia severity

To determine whether the cognitive status of patients with dominantly inherited spinocerebellar ataxia (DSCA) might be related to neurologic severity, we administered a comprehensive neuropsychological test battery to 43 patients with DSCA, ranging in ataxia severity from mild to end-stage. As compared with the controls, the mildly ataxic patients scored normally or close to normal as a group on all of the neuropsychological tests. In contrast, approximately one-half of the moderately and all of the severely ataxic patients showed poor performance, independent of age, Hamilton Rating Scale for Depression score, or education, on the Wisconsin Card Sorting Test, suggesting impaired executive system function. In addition, a subgroup of these patients had a neuropsychological profile suggestive of mild generalized cognitive impairment. We conclude that DSCA is not a homogeneous group of disorders with respect to cognitive status and that the neurologic severity of the disorder is a major factor. Impaired executive system function could be explained by damage to olivopontocerebellar system control over cerebral cortical function or to damage to other neuronal systems (especially cholinergic) that degenerate in parallel with the olivopontocerebellar system.

Frontal and parietal lobe dysfunction in depression: delayed alternation and tactile learning deficits

To evaluate frontal and parietal lobe involvement in depression, behavioral tests sensitive to damage in these regions were administered to depressed patients over age 50. Delayed alternation (DA), delayed response and object alternation were used to assess dorsolateral frontal and orbitofrontal function. Tactile learning problems (TOL and TRL) assessed parietal lobe integrity. Depressed patients were significantly impaired on DA, TOL and TRL, suggesting spatial memory (DA) and tactile learning deficits. The functional neuroanatomy underlying these deficits may share features with Parkinson's and Alzheimer's diseases.

Are the associations between Alzheimer's disease and polymorphisms in the apolipoprotein E and the apolipoprotein CII genes due to linkage disequilibrium?

Allele frequencies for polymorphisms in the apolipoprotein E and the apolipoprotein CII genes were determined in subjects of Ashkenazi Jewish origin with late-onset Alzheimer's disease and in unaffected control subjects from the same ethnic group. A significant association was observed between late-onset Alzheimer's disease and the epsilon 4 (112Cys-->Arg) allele of apolipoprotein E; however, no association was detected with apolipoprotein CII. These results suggest that the association with epsilon 4 is probably not due to linkage disequilibrium.

DNA sequences in the promoter region of the NF1 gene are highly conserved between human and mouse

The gene for type 1 neurofibromatosis (NF1) is most highly expressed in brain and spinal cord, although low levels of mRNA can be found in nearly all tissues. As a first step in investigating the regulation of NF1 gene expression, we have cloned and sequenced the promoter regions of the human and mouse NF1 genes and mapped the transcriptional start sites in both species. We report here that the 5' ends of the human and murine NF1 genes are highly conserved. While no discernable TATA or CCAAT box sequences are seen, transcription initiates at identical sites in both species, 484 nucleotides upstream of the ATG initiation codon in the human gene. The human and mouse NF1 genes share particularly high sequence homology (95%) between nucleotides -33 and +261 and contain several perfectly conserved transcription factor binding site motifs, including a cAMP response element, several AP2 consensus binding sites, and a serum response element. The high conservation of these sequences indicates that they are likely to be significant in the regulation of NF1 gene expression.

SPECT for differential diagnosis of dementia and correlation of rCBF with cognitive impairment

99mTc-HM-PAO single photon emission computed tomography (SPECT) was used to image 30 patients referred for the assessment of dementia. SPECT images revealed various patterns of regional cerebral perfusion (rCBF) in the subgroups of patients with the clinical diagnoses of Alzheimer's disease (AD, n = 14), Pick's disease (n = 1), and multi-infarct dementia (n = 7). In three patients, SPECT clarified the clinical differential diagnostic possibilities. Using a relative rCBF quantification technique, the relationship between specific cognitive impairments and rCBF in the AD patients was determined. There was a significant correlation between language impairment and left hemisphere hypoperfusion, whereas, apraxia correlated with hypoperfusion in the left parietal region. Thus, HM-PAO SPECT is useful as an aid in the differential diagnosis of dementia and the technique of relative rCBF quantification with SPECT may contribute to the understanding of the clinico-anatomical relations of cognitive deficits in dementia.