Isoscaling as a measure of symmetry energy in the lattice gas model

The energetic properties of nuclear clusters inside a low-density, finite-temperature medium are studied with a lattice gas model including isospin dependence and Coulomb forces. Important deviations are observed with respect to the Fisher approximation of an ideal gas of noninteracting clusters, but a simple modified energy-density functional can still describe the global energetics. The multifragmentation regime is dominated by combinatorial effects, but the isoscaling of the largest fragment appears to be a promising observable for the experimental measurement of the symmetry energy.

Cutaneous leishmaniasis due to Leishmania chagasi/Le. infantum in an endemic area of Guarico State, Venezuela

This study reports cutaneous leishmaniasis (CL) caused by Leishmania chagasi/Le. infantum in Venezuela, with some atypical characteristics. Out of 63 cases of CL in the suburbs of Altagracia de Orituco, Guarico State, Venezuela, 30 presented clinical, parasitological, immunological and epidemiological features different from those of the classical CL known in the country. The initial lesion was small and nodular, which, if not treated, might progress to a superficial ulcer. No secondary infection was observed. The identification of the isolates was carried out by molecular techniques. Twelve species of phlebotomine sandflies were caught, the most abundant being Lutzomyia evansi and Lu. longipalpis s.l., known vectors of Le. chagasi/Le. infantum. The existence of Le. chagasi/Le. infantum and its vectors in an endemic area of CL has implications and we suggest that epidemiological studies should be carried out to obtain a clearer picture of the extent of this CL form in Venezuela.

Cerebral microbleeds in the population based AGES-Reykjavik study: prevalence and location

BACKGROUND AND PURPOSE

Incidental foci of signal loss suggestive of cerebral microbleeds (CMBs) are frequent findings on gradient echo T2* weighted MRI (T2* MRI) of patients with haemorrhagic or ischaemic stroke. There are few prevalence data on older populations. This paper reports on the prevalence and location of CMBs in a community based cohort of older men and women (born 1907-1935) who participated in the Age Gene/Environment Susceptibility (AGES)-Reykjavik Study, a population based cohort study that followed the Reykjavik Study

METHODS

As part of the examination, all eligible and consenting cohort members underwent a full brain MRI, and blood was drawn for genotyping. Results are based on the first 1962 men (n = 820) and women (n = 1142), mean age 76 years, with complete MRI and demographic information available.

RESULTS

Evidence of CMBs was found in 218 participants (11.1% (95% CI 9.8% to 12.6%)); men had significantly more CMBs than women (14.4% vs 8.8%; p = 0.0002, age adjusted). The prevalence of CMBs increased with age (p = 0.0001) in both men (p = 0.006) and women (p = 0.007). CMBs were located in the cerebral lobes (70%), the basal ganglia region (10.5%) and infratentorium (18.6%). Having a CMB was significantly associated with a homozygote Apo E epsilon4epsilon4 genotype (p = 0.01).

CONCLUSION

Cerebral microbleeds are common in older persons. The association with homozygote Apo E epsilon4 genotype and finding a relative predominance in the parietal lobes might indicate an association with amyloid angiopathy.

Plasma amyloid levels and the risk of AD in normal subjects in the Cardiovascular Health Study

OBJECTIVES

To examine the association between incident Alzheimer disease (AD), and plasma A beta 1-40 and A beta 1-42 levels in normal and mild cognitive impairment (MCI) subjects in a subgroup of participants of the Cardiovascular Health Study Cognition Study.

METHODS

We determined the plasma A beta 1-40 and A beta 1-42 levels of 274 nondemented subjects (232 normals and 42 with MCI) in 1998-1999 and repeated the measurements in 2002-2003. The mean age of the subjects at baseline was 79.3 +/- 3.6 years. We examined the association between A beta levels and incident AD over the ensuing 4.5 years, controlling for age, cystatin C level (marker of glomerular function), apolipoprotein E-4 allele, Modified-Mini-Mental State Examination scores, and MRI-identified infarcts.

RESULTS

In an unadjusted prospective model in normal subjects, both A beta 1-40 and A beta 1-42 levels in 1998-1999 were associated with incident AD (n = 55) in 2002-2003 (longitudinal analysis). In the fully adjusted multivariate model, neither A beta 1-42 nor A beta 1-40 nor their ratio was associated with incident AD. However, adjustment had a very small effect on point estimates for A beta 1-42, from an odds ratio (OR) of 1.61 (p = 0.007) in the unadjusted model to an OR of 1.46 (p = 0.08) in the fully adjusted model. In 2002-2003 (cross-sectional analysis), only the unadjusted models showed that both peptides were associated with AD.

CONCLUSIONS

Plasma A beta levels are affected by age and by systemic and CNS vascular risk factors. After controlling for these conditions, A beta-40 and A beta 1-42 are weak predictors of conversion to Alzheimer disease (AD) in normal subjects and are only weakly associated with AD in cross-sectional analysis. Consequently, plasma levels of A beta do not seem to be useful biomarkers for AD.

Generalized tensor-based morphometry of HIV/AIDS using multivariate statistics on deformation tensors

This paper investigates the performance of a new multivariate method for tensor-based morphometry (TBM). Statistics on Riemannian manifolds are developed that exploit the full information in deformation tensor fields. In TBM, multiple brain images are warped to a common neuroanatomical template via 3-D nonlinear registration; the resulting deformation fields are analyzed statistically to identify group differences in anatomy. Rather than study the Jacobian determinant (volume expansion factor) of these deformations, as is common, we retain the full deformation tensors and apply a manifold version of Hotelling's $T(2) test to them, in a Log-Euclidean domain. In 2-D and 3-D magnetic resonance imaging (MRI) data from 26 HIV/AIDS patients and 14 matched healthy subjects, we compared multivariate tensor analysis versus univariate tests of simpler tensor-derived indices: the Jacobian determinant, the trace, geodesic anisotropy, and eigenvalues of the deformation tensor, and the angle of rotation of its eigenvectors. We detected consistent, but more extensive patterns of structural abnormalities, with multivariate tests on the full tensor manifold. Their improved power was established by analyzing cumulative p-value plots using false discovery rate (FDR) methods, appropriately controlling for false positives. This increased detection sensitivity may empower drug trials and large-scale studies of disease that use tensor-based morphometry.

In leukapheresis products from non-Hodgkin's lymphoma patients, the immature hematopoietic progenitors show higher CD90 and CD34 antigenic expression

Damage to the stem cell progenitors caused by the chemotherapy received in patients diagnosed with non-Hodgkin's lymphoma (NHL) may be an important factor limiting progenitor cell mobilization. The aim of the present analysis was to evaluate the effect of the chemotherapy on the different progenitor cell subpopulations obtained in the leukapheresis. For this purpose, a combination of immunophenotype and functional assays has been performed in 26 mobilized peripheral blood (PB) samples from NHL patients and 36 healthy donors. The different progenitor subpopulations analyzed by flow cytometry significantly correlated with the corresponding populations assessed by functional assays in both healthy donors and NHL patients (p<0.05, r>0.5). The number of committed CFU-GM was similar in both groups (p=0.246), but we found significant decrease in the number of BFU-E and more immature progenitors in PB from NHL patients as compared to donors (p<0.05). Moreover, the number of total CFU was significantly lower in NHL patients (p=0.007). Accordingly, CD34+ cells (p=0.018) and CD34+ subpopulations was decreased in NHL patients. Nevertheless, CD90 and CD34 intensity was significantly higher within CD34+ cells from NHL patients as compared to donors. However, although numerically reduced non-committed CD34+ cells are more immature in chemotherapy mobilized NHL patients. In summary, our results show that all NHL hematopoietic progenitors, analyzed by both immunophenotypical and functional approaches, are impaired in leukapheresis products.

Effect of metal ions and calcium on purified PON1 and PON3 from rat liver

The effect of several metal ions and calcium on purified paraoxonases (PON1 and PON3) from rat liver was studied. PON1 and PON3 were also inhibited by EDTA and both enzyme activities were restored by the addition of free calcium. The reactivation by calcium was a time-dependent effect for PON1; however, this was not the case for PON3. We also studied the response of PON1 and PON3 to several inhibitors: Co, Cu, Mn, Hg and p-hydroxymercurybenzoate (pOHMB), and determined the type of inhibition and the inhibition constants. Among all the compounds tested, mercurials (Hg and pOHMB) were the most potent inhibitors of PON1. For PON3 mercurials and copper showed the highest inhibitory potency. Purified PON3 also showed different inhibition patterns as compared to PON1. A comparison of PON1 and PON3 shows qualitative and quantitative differences in the sensitivity against the inhibitors tested, showing major differences in the case of cobalt, copper and pOHMB, which may be related to structural differences of both PONs. These results increase our knowledge of the biochemical properties of PON1 and PON3 and may help in the understanding of their physiological role as a potential detoxification mechanism against environmental metal ions.

Lewy bodies in the amygdala increase risk for major depression in subjects with Alzheimer disease

OBJECTIVE

To determine the relationship between major depression and the presence of Lewy bodies (LBs) in patients with Alzheimer disease (AD).

METHODS

The authors examined the presence of major depression in 267 pathologically diagnosed AD cases with Mini-Mental State Examination (MMSE) scores >9. LBs were identified in 142 (53%) patients using alpha-synuclein immunohistochemistry. Subjects were classified according to the Consensus Guidelines for the Clinical and Pathologic Diagnosis of Dementia with LB: 1 to 2 (n = 21), 3 to 6 (n = 26), and 7 to 10 (n = 69). Twenty-six patients had LB only in the amygdala. All cases with LB scores 7 to 10 (or cortical) had amygdala LBs. The association between LBs and major depression was examined with logistic regression analyses, controlled for age at study entry, education level, MMSE scores, antidepressant use, follow-up time, and the presence of cerebrovascular disease.

RESULTS

Major depression was present in 11 (9%) AD alone cases, and in 25 (18%) of the AD + LBs cases; amygdala: 8 (31%), scores 1 to 2: 1 (5%), scores 3 to 6: 3 (11.5%), and scores 7 to 10: 13 (14%). Major depression was associated with LBs, in general (relative risk [RR] = 3.06, 95% CI: 1.25 to 7.46), with amygdala only LBs (RR = 8.56 (95% CI: 1.83 to 40.3), and with LB scores 7 to 10 (RR = 3.83, 95% CI: 1.33 to 11.0). There was an association between all amygdala LBs cases (amygdala only LBs + LB scores 7 to 10) and major depression (RR = 4.77, 95% CI: 1.78 to 12.7), but no association was noted between LBs and depression in the absence of amygdala LBs (RR = 0.96, 95% CI: 0.46 to 1.06).

CONCLUSION

Lewy bodies (LBs) in the amygdala and in cortical areas increase the risk for major depression in Alzheimer disease. What is common in these two groups is the presence of LBs in the amygdala. That is, all of the cases with cortical LBs also had LBs in the amygdala, making this region the critical area for the development of depression.

Neuropsychological characteristics of mild cognitive impairment subgroups

OBJECTIVE

To describe the neuropsychological characteristics of mild cognitive impairment (MCI) subgroups identified in the Cardiovascular Health Study (CHS) cognition study.

METHODS

MCI was classified as MCI-amnestic type (MCI-AT): patients with documented memory deficits but otherwise normal cognitive function; and MCI-multiple cognitive deficits type (MCI-MCDT): impairment of at least one cognitive domain (not including memory), or one abnormal test in at least two other domains, but who had not crossed the dementia threshold. The MCI subjects did not have systemic, neurological, or psychiatric disorders likely to affect cognition.

RESULTS

MCI-AT (n = 10) had worse verbal and non-verbal memory performance than MCI-MCDT (n = 28) or normal controls (n = 374). By contrast, MCI-MCDT had worse language, psychomotor speed, fine motor control, and visuoconstructional function than MCI-AT or normal controls. MCI-MCDT subjects had memory deficits, though they were less pronounced than in MCI-AT. Of the MCI-MCDT cases, 22 (78.5%) had memory deficits, and 6 (21.5%) did not. MCI-MCDT with memory disorders had more language deficits than MCI-MCDT without memory disorders. By contrast, MCI-MCDT without memory deficits had more fine motor control deficits than MCI-MCDT with memory deficits.

CONCLUSIONS

The most frequent form of MCI was the MCI-MCDT with memory deficits. However, the identification of memory impaired MCI groups did not reflect the true prevalence of MCI in a population, as 16% of all MCI cases and 21.5% of the MCI-MCDT cases did not have memory impairment. Study of idiopathic amnestic and non-amnestic forms of MCI is essential for an understanding of the aetiology of MCI.

Classification of vascular dementia in the Cardiovascular Health Study Cognition Study

OBJECTIVE

To describe the diagnostic classification of subjects with incident vascular dementia (VaD) participating in the Cardiovascular Health Study (CHS) Cognition Study.

METHODS

The CHS classified 480 incident cases between 1994 and 1999 among 3,608 CHS participants who had brain MRI in 1992 through 1994 and in 1997 through 1998. The patients were diagnosed before and after reviewing the brain MRI.

RESULTS

The pre-MRI classification showed that 52 participants had VaD and 76 had both Alzheimer disease (AD) and VaD. The post-MRI classification showed that the Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV) criteria classified 61 subjects as having VaD, the National Institute of Neurological Disorders and Stroke-Association Internationale pour la Recherche et l'Enseignement en Neurosciences (NINDS-AIREN) criteria classified 43 subjects as having probable VaD and 10 as possible VaD, and the State of California Alzheimer's Disease Diagnostic and Treatment Center (ADDTC) criteria classified 117 as having probable VaD and 96 as possible. The combination of the ADDTC and National Institute of Neurological and Communication Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria was used to examine the spectrum of vascular disease in dementia. The dementia was attributable to only vascular factors in 56 cases (probable VaD); VaD coexisted with AD in 61 cases, although the VaD component was the leading cause of dementia (probable VaD with AD); AD was the leading cause of dementia in 61 cases (possible VaD and probable AD); and in 29 cases, it was not clear that either AD or VaD was the primary diagnosis (possible AD and possible VaD).

CONCLUSIONS

None of the clinical criteria for VaD identified the same group of subjects. The diagnosis of vascular dementia is difficult in epidemiologic studies because poststroke dementia can be due to Alzheimer disease (AD) and evidence of vascular disease can be found in the MRI of dementia cases without clinical strokes. Whether the clinical progression is related to AD pathology or vascular disease is difficult to establish.

Determinants of vascular dementia in the Cardiovascular Health Cognition Study

OBJECTIVE

The authors evaluated 3,375 participants without dementia at the time of MRI in 1991 to 1994 over 5.7 years for incident dementia and type of dementia.

METHODS

Incidence of and risk factors for vascular dementia (VaD) were measured using both pre-MRI and modified State of California Alzheimer's Disease Diagnostic and Treatment Centers (ADDTC) post-MRI review and further classified Alzheimer disease (AD) by the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association (NINCDS-ADRDA) criteria.

RESULTS

Approximately 44% (213) of 480 incident dementia cases were classified as possible or probable VaD by ADDTC. The incidence of VaD increased with age and was greater in blacks than whites. Risk factors for VaD included age, Modified Mini-Mental State Examination, high white matter grade, number of MRI infarcts, ventricular size, and history of stroke.

CONCLUSIONS

Vascular disease in the brain is prevalent among incident dementia cases. There is a substantial overlap between cases classified as Alzheimer disease by Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association and vascular dementia (VaD) by modified State of California Alzheimer's Disease Diagnostic and Treatment Centers criteria. The substantial contribution of vascular disease would be missed without inclusion of MRI. Treatment of risk factors for VaD could have an important impact on incidence of dementia.

Bimodality as a signal of a liquid-gas phase transition in nuclei?

We use the heavy-ion phase-space exploration model to discuss the origin of the bimodality in charge asymmetry observed in nuclear reactions around the Fermi energy. We show that it may be related to the important angular momentum (spin) transferred into the quasiprojectile before secondary decay. As the spin overcomes the critical value, a sudden opening of decay channels is induced and leads to a bimodal distribution for the charge asymmetry. In the model, it is not assigned to a liquid-gas phase transition but to specific instabilities in nuclei with high spin. Therefore, we propose to use these reactions to study instabilities in rotating nuclear droplets.

Diagnosis and management of dementia with Lewy bodies: third report of the DLB Consortium

The dementia with Lewy bodies (DLB) Consortium has revised criteria for the clinical and pathologic diagnosis of DLB incorporating new information about the core clinical features and suggesting improved methods to assess them. REM sleep behavior disorder, severe neuroleptic sensitivity, and reduced striatal dopamine transporter activity on functional neuroimaging are given greater diagnostic weighting as features suggestive of a DLB diagnosis. The 1-year rule distinguishing between DLB and Parkinson disease with dementia may be difficult to apply in clinical settings and in such cases the term most appropriate to each individual patient should be used. Generic terms such as Lewy body (LB) disease are often helpful. The authors propose a new scheme for the pathologic assessment of LBs and Lewy neurites (LN) using alpha-synuclein immunohistochemistry and semiquantitative grading of lesion density, with the pattern of regional involvement being more important than total LB count. The new criteria take into account both Lewy-related and Alzheimer disease (AD)-type pathology to allocate a probability that these are associated with the clinical DLB syndrome. Finally, the authors suggest patient management guidelines including the need for accurate diagnosis, a target symptom approach, and use of appropriate outcome measures. There is limited evidence about specific interventions but available data suggest only a partial response of motor symptoms to levodopa: severe sensitivity to typical and atypical antipsychotics in approximately 50%, and improvements in attention, visual hallucinations, and sleep disorders with cholinesterase inhibitors.

Functional neuroimaging indicators of successful executive control in the oldest old

Attentional control, motor planning abilities, and executive cognitive functions (ECF) rapidly decline with age. In particular, older adults experience difficulty in manipulating selected motor responses in the presence of conflicting or distracting information. To examine age-related changes in the neural substrates of the attentional and motor planning components of ECF, we assessed the patterns of brain activation in 8 cognitively normal older adults (mean age 81.5) and 20 young individuals (mean age 23.0) while they responded to low and high loads of attentional demands of the Preparing to Overcome Prepotency (POP) task. In the POP task, the selection of one out of two possible motor responses in the presence of increasing attentional task loads determines the accuracy of the performance. Older individuals were slower than young adults (P < 0.001) but achieved a strikingly high accuracy similar to the young group (P = 0.2), regardless of the task load. Both groups showed a load-related fMRI signal increase in the anterior cingulate cortex (ACC), posterior parietal cortex (PPC: Brodmann areas 7 and 40), and dorsolateral prefrontal cortex (dLPFC: Brodmann areas 9, 45, and 46) bilaterally. Compared to young individuals, older adults had lower activation in dLPFC (Brodmann areas 9, 45, and 46: P = 0.007, P = 0.043, and P = 0.040) and Brodmann area 7, P = 0.002. Activation in Brodmann areas 40 and ACC was similar in the two groups (P > 0.05). Among older adults, the most successful performers were those who responded to increasing task loads with greater activation in PPC (Brodmann area 40), despite lower dLPFC activation. Older adults who are able to perform executive control tasks as well as young adults, also seem to implement speed-accuracy trade-off strategies which may rely on increased parietal activation.

Genetic association between the APOE*4 allele and Lewy bodies in Alzheimer disease

OBJECTIVE

To explore the association between APOE*4 and pathologically confirmed cases of the Lewy body (LB) variant of Alzheimer disease (AD).

METHODS

With use of alpha-synuclein (AS) immunohistochemistry, LBs were detected in 74 of 131 (56.5%) of the AD + LB cases; the remaining 57 cases (43.5%) did not have LBs.

RESULTS

There were no differences in gender or age between Caucasian subjects with AD + LB or AD alone or control subjects. The APOE*4 allele frequency was highest in the AD + LB group (47.3%; 95% CI = 37.8 to 57.0%), intermediate in the AD-alone group (35.1%; 95% CI = 25.3 to 46.3%), and lowest in the control group (14.2%; 95% CI = 10.5 to 18.9%). With use of logistic regression analysis, the odds of having AD + LB vs AD alone were 2.1-fold (95% CI = 1.0 to 4.5, p = 0.055) greater in persons with an APOE*4 allele than in those without an APOE*4 allele.

CONCLUSION

The APOE*4 allele is associated with the presence of concomitant Lewy bodies in Alzheimer disease.

Long-distance frequency dissemination with a resolution of 10(-17)

We use a new technique to disseminate microwave reference signals along ordinary optical fiber. The fractional frequency resolution of a link of 86 km in length is 10(-17) for a one day integration time, a resolution higher than the stability of the best microwave or optical clocks. We use the link to compare the microwave reference and a CO2/OsO4 frequency standard that stabilizes a femtosecond laser frequency comb. This demonstrates a resolution of 3 x 10(-14) at 1 s. An upper value of the instability introduced by the femtosecond laser-based synthesizer is estimated as 1 x 10(-14) at 1 s.

Isotopic scaling and the symmetry energy in spectator fragmentation

Isotopic effects in the fragmentation of excited target residues following collisions of 12C on (112,124)Sn at incident energies of 300 and 600 MeV per nucleon were studied with the INDRA 4pi detector. The measured yield ratios for light particles and fragments with atomic number Z < or = 5 obey the exponential law of isotopic scaling. The deduced scaling parameters decrease strongly with increasing centrality to values smaller than 50% of those obtained for the peripheral event groups. Symmetry-term coefficients, deduced from these data within the statistical description of isotopic scaling, are near gamma = 25 MeV for peripheral and gamma < 15 MeV for central collisions.

Morphometric analysis of gray matter volume in demented older adults: exploratory analysis of the cardiovascular health study brain MRI database

We tested the feasibility of a fully automated brain MRI voxel count technique--automated labeling pathway (ALP)--in a sample of 15 demented and 13 cognitively normal women (age 75-85 years) participating to the Cardiovascular Health Study (CHS). We hypothesized that ALP would replicate well-established findings of the anatomical correlates of dementia. In particular, we hypothesized that ALP volumetric measures would: (1) significantly differ between cognitively normal and demented women in those brain areas that are established markers for diagnosis of dementia (temporal and medial temporal lobes, hippocampus, amygdala and parahippocampus) but not in other brain areas (e.g., occipital lobe, visual cortex, motor cortex) and (2) correlate with visual ratings of brain disease which have been previously collected as part of the CHS. ALP required minimal operator intervention (input of brain images and verification of misalignments) and employed computer time of about 1 h per brain. ALP detected significant focal volumetric differences in the limbic system (p values between groups for hippocampus and parahippocampus: 0.002 and 0.005, respectively), temporal lobe (p < 0.0001) and caudate (p = 0.009), but not in other brain areas (e.g. occipital lobe, visual or motor cortex). Furthermore, ALP measures of medial temporal lobe atrophy strongly correlated with CHS visual ratings of ventricular enlargement (r(2) = 0.6, p = 0.002 for medial temporal lobe). In conclusion, ALP-detected focal brain atrophy was strongly associated with dementia. Because of its fully automated design, ALP technique is an ideal candidate to assess whether volumetric measures of specific areas can discriminate dementia better than currently available measures of global brain atrophy in large epidemiological studies.

Preclinical Alzheimer disease: Neuropsychological test performance 1.5 to 8 years prior to onset

OBJECTIVE

To determine if individuals ultimately diagnosed with Alzheimer disease (AD) exhibited evidence of cognitive impairment on neuropsychological tests administered between 1.5 years and 8.1 years before dementia onset.

METHODS

A total of 693 community-dwelling individuals, part of the Cardiovascular Health Study, completed a neuropsychological test battery in 1991/92. Subjects were followed annually over the next 8 years (median follow-up = 7.4 years). Seventy-two individuals were ultimately diagnosed with AD (median follow-up = 4.5 years): 24 with AD onset 1.5 to 3.4 years after baseline neuropsychological testing, 20 with AD onset 3.5 to 5.0 years after testing, and 28 with onset 5.1 to 8.1 years after testing. A total of 621 individuals remained nondemented throughout the 8 years of follow-up (median follow-up = 7.5 years).

RESULTS

Subjects ultimately diagnosed with AD had poorer scores on baseline neuropsychological measures than subjects who remained nondemented. Although individuals closest to AD onset (i.e., 1.5 to 3.4 years) performed the most poorly, cognitive impairment was detected in individuals who did not develop AD until 5 to 8 years later.

CONCLUSIONS

Cognitive changes can be detected well before onset of Alzheimer disease.