The role of carotid stenosis in vascular cognitive impairment

The role of carotid stenosis in vascular cognitive impairment was reviewed using Medline, EMBASE, PsychLit and PsychInfo databases using the words "carotid stenosis", "neuropsychological tests" and "endarterectomy". Limited evidence exists for frontal lobe dysfunction associated with carotid stenosis, but there is a lack of systematic and prospective studies carried out in consecutive patients, including appropriate neuropsychological and MRI assessment. Possible pathophysiological processes suggested for cognitive impairment associated with carotid stenosis are suggested; these include chronic ischaemia and lacunar infarction; such mechanisms and resultant pathologies may co-exist in the presence of large-artery atheroma.

Mining DNA microarray data using a novel approach based on graph theory

The recent demonstration that biochemical pathways from diverse organisms are arranged in scale-free, rather than random, systems [Jeong et al., Nature 407 (2000) 651-654], emphasizes the importance of developing methods for the identification of biochemical nexuses--the nodes within biochemical pathways that serve as the major input/output hubs, and therefore represent potentially important targets for modulation. Here we describe a bioinformatics approach that identifies candidate nexuses for biochemical pathways without requiring functional gene annotation; we also provide proof-of-principle experiments to support this technique. This approach, called Nexxus, may lead to the identification of new signal transduction pathways and targets for drug design.

Neonatal iron nutrition

Preterm infants are prone to iron deficiency. Their total body iron content at birth is low and gets further depleted by clinical practices such as uncompensated phlebotomy losses and exogenous erythropoietin administration during the neonatal period. Early iron deficiency appears to adversely affect cognitive development in human infants. To maintain iron sufficiency and meet the iron demands of catch-up postnatal growth, iron supplementation is prudent in preterm infants. A dose of 2-4 mg/kg/day is recommended for preterm infants who are fed exclusively human milk. A dose of 6 mg/kg/day or more is needed with the use of exogenous erythropoietin or to correct preexisting iron deficiency. However, due to the poor antioxidant capabilities of preterm infants and the potential role of iron in several oxidant-related perinatal disorders, indiscriminate iron supplementation should be avoided.

Physical and sexual abuse histories in patients with eating disorders: a comparison of Japanese and American patients

Physical and sexual abuse among patients with eating disorders has been a focus of attention in Western countries, however, there is no study comparing the incidence of these factors in Western and Asian countries. Japanese subjects consisted of 38 patients with anorexia nervosa restricting type (AN-R), 46 patients with anorexia nervosa binge eating/purging type (AN-BP), 76 patients with bulimia nervosa purging type (BN) and 99 controls. Subjects from the USA consisted of 29 AN-R, 34 AN-BP and 16 BN. The Physical and Sexual Abuse Questionnaire was administered to all subjects. Minor sexual abuse such as confronting exhibitionism or being fondled by a stranger tended to be more prevalent among Japanese subjects, while victimization by rape or incest was more prevalent among USA subjects. Conversely, physical abuse history was similarly distributed across each diagnostic subgroup in both countries. Events related to physical abuse, such as an abusive family background, may contribute whether eating disorder patients are restricting or bulimic and regardless of culture.

APAP, a sequence-pattern recognition approach identifies substance P as a potential apoptotic peptide

We have previously described a novel cancer chemotherapeutic approach based on the induction of apoptosis in targeted cells by homing pro-apoptotic peptides. In order to improve this approach we developed a computational method (approach for detecting potential apoptotic peptides, APAP) to detect short PAPs, based on the prediction of the helical content of peptides, the hydrophobic moment, and the isoelectric point. PAPs are toxic against bacteria and mitochondria, but not against mammalian cells when applied extracellularly. Among other peptides, substance P was identified as a PAP and subsequently demonstrated to be a pro-apoptotic peptide experimentally. APAP thus provides a method to detect and ultimately improve pro-apoptotic peptides for chemotherapy.

The yeast Na+/H+ exchanger Nhx1 is an N-linked glycoprotein. Topological implications

Nhx1, the endosomal Na(+)/H(+) exchanger of Saccharomyces cerevisiae represents the founding member of a newly emerging subfamily of intracellular Na(+)/H(+) exchangers. These proteins share significantly greater sequence homology to one another than to members of the mammalian Na(+)/H(+) exchanger (NHE) family encoding plasma membrane Na(+)/H(+) exchangers. Members of both subtypes are predicted to share a common organization, with an N-terminal transporter domain of transmembrane helices followed by a C-terminal hydrophilic tail. In the present study, we show that Nhx1 is an asparagine-linked glycoprotein and that the sites of glycosylation map to two residues within the C-terminal stretch of the polypeptide. This is the first evidence, to date, for glycosylation of the C-terminal region of any known NHE isoform. Importantly, the mapping of N-linked glycosylation to the C-terminal domain of Nhx1 is indicative of an unexpected membrane topology, particularly with regard to the orientation of the tail region. Although one recent study demonstrated that certain epitopes in the C-terminal domain of NHE3 were accessible from the exoplasmic side of the plasma membrane (Biemesderfer, D., DeGray, B., and Aronson, P. S. (1998) J. Biol. Chem. 273, 12391-12396), numerous other studies implicate a cytosolic disposition for the hydrophilic C-terminal tail of plasma membrane NHE isoforms. Our analysis of the glycosylation of Nhx1 is strongly indicative of residence of at least some portion of the hydrophilic tail domain within the endosomal lumen. These findings imply that the organization of the tail domain may be more complex than previously assumed.

Indocyanine green angiography of the anterior segment in patients undergoing strabismus surgery

BACKGROUND

Anterior segment imaging using fluorescein angiography is only suitable in lightly pigmented irides as the brown pigmentation of the iris masks fluorescein transmission. Indocyanine green (ICG) angiography has excellent penetration of pigment epithelium and, therefore, has potential application in detecting perfusion changes of dark irides after strabismus surgery.

METHODS

A prospective study was conducted on patients older than 15 years undergoing strabismus surgery. A fundus camera was focused on the arteriolar tufts of the pupillary margin and 50 mg of ICG (concentration of 12.5 mg/ml) was given intravenously. Images were then obtained at 1 minute intervals of 5 minutes' duration.

RESULTS

45 patients with a mean age of 54.6 years and a mean follow up period of 8.6 weeks were studied. There were 23 patients in the primary surgery group, 11 in the secondary surgery group, and 11 in the staged group. Iris ICG angiograms were successfully performed in all patients. No persistent filling defect was detected in the primary and secondary horizontal recti surgery groups or in the secondary or staged vertical and combined vertical rectus groups 6-8 weeks postoperatively. 57% of both primary vertical and combined vertical and horizontal groups showed defects in the early postoperative phase. Only three cases demonstrated late perfusion defects in this series.

CONCLUSION

ICG can detect iris perfusion changes in dark irides after strabismus surgery. Iris reperfusion was achieved in the majority of the cases.

Depression in older people with mild stroke, carotid stenosis and peripheral vascular disease: a comparison with healthy controls

BACKGROUND

Although depression has a recognised association with stroke, the role of "silent" cerebrovascular pathology associated with carotid stenosis and peripheral vascular disease remains unexplored.

METHODS

Four groups of 25 community residents aged 65 and over were recruited, comprising first anterior circulation stroke, carotid stenosis accompanied by transient ischaemic attack, peripheral vascular disease and a non-vascular control group. All participants were interviewed using the Hamilton Rating Scale for Depression [HRSD] (including a modified version) and Geriatric Depression Scale. DSM IV criteria for major depression and measures of handicap, social support and physical illness were also administered. Head computerised tomography (CT) scans were performed on stroke patients to examine the relationship between lesion location and depression.

RESULTS

One hundred patients were interviewed. Stroke patients were more likely to live in a nursing home and had less social support than other groups. Mean scores on the modified Hamilton and Geriatric Depression Scales were higher in stroke and carotid stenosis groups than controls. Patients with stroke did not show a higher prevalence of DSM IV major depressive disorder than those with carotid stenosis. There was no relationship between the presence of lesions affecting the frontal/subcortical system and prevalence/severity of depression.

LIMITATIONS

Small numbers, mortality of stroke patients in hospital, possible selection bias in the control group and use of a previously unvalidated depression rating scale all limit the study.

CONCLUSIONS

A possible role for carotid stenosis in the pathogenesis of depressive disorder is suggested. Larger studies incorporating brain imaging may be required to examine the mechanism of this association more closely. The use of a shorter version of the HRSD in older people with cerebrovascular disease may warrant further exploration.

Personality traits among currently eating disordered, recovered and never ill first-degree female relatives of bulimic and control women

BACKGROUND

A combined family study and recovered study design was utilized to examine several hypothesized relationships between personality and bulimia nervosa (BN).

METHODS

We studied 47 women with a lifetime history of DSM-III-R BN (31 currently ill and 16 recovered), 44 matched control women (CW) with no history of an eating disorder (ED), and their first-degree female relatives (N = 89 and N = 100, respectively), some of whom had current or previous EDs.

RESULTS

BN probands' relatives with no ED history had significantly elevated levels of perfectionism, ineffectiveness, and interpersonal distrust compared to CW probands' relatives with no ED history. In contrast, diminished interoceptive awareness, heightened stress reactivity and perfectionistic doubting of actions were found among the previously eating disordered relatives of bulimic probands compared to their never ill relatives. Finally, a sense of alienation and emotional responsivity to the environment were elevated among currently ill compared to recovered bulimic probands.

CONCLUSIONS

The fact that perfectionism, ineffectiveness and interpersonal distrust are transmitted independently of an ED in relatives suggests that they may be of potential aetiological relevance for BN. In contrast, diminished interoceptive awareness, heightened stress reactivity and perfectionistic doubting of actions are more likely consequent to, or exacerbated by, previously having experienced the illness. Finally, a sense of alienation and emotional responsivity to the environment are more likely to be associated with currently having BN.

meso-Aryl smaragdyrins: novel anion and metal receptors

An easy synthesis of core-modified meso-aryl smaragdyrins containing oxygen and sulfur in addition to pyrrole nitrogens has been achieved through an alpha-alpha coupling involving modified tripyrrane and dipyrromethane. The complexation behavior of these macrocycles toward anions (Cl-, F-, AMP-) and metal cations (Rh(I), Ni(II)) is reported. Specifically, it has been shown that the Rh(I) and Ni(II) ions bind to the smaragdyrin skeleton in its free base form. X-ray structural studies of Rh(I) complex 1 indicate an eta 2-type coordination involving only one imino and one amino nitrogen of the dipyrromethane unit. However, all four bipyrrole nitrogens participate in the coordination with the Ni(II) ion. Furthermore, Ni(II) coordination oxidizes the ligand, and the complex is formulated as the pi-cation radical of nickel(II) smaragdyrin. The anion complexation is followed in both the solid and solution phases. Solution studies reveal that the binding constants of the ions with the protonated form of smaragdyrin vary as F- > AMP- > Cl-. The X-ray structure of the chloride anion complex reveals that the chloride ion is bound above the cavity of the smaragdyrin macrocycle through three N-H...Cl hydrogen bonds. Crystal data with Mo K alpha (lambda = 0.710,73 A) are as follows: 1, C41H27N4O3Rh, a = 11.836(8) A, b = 12.495(9) A, c = 12.670(2) A, alpha = 69.09(6) degrees, beta = 78.78(6) degrees, gamma = 77.02(5) degrees, V = 1692.1(17) A3, Z = 2, triclinic, space group P-1, R1 (all data) = 0.0471; 4.HCl, C41H29N4O1Cl, a = 11.878(2) A, b = 17.379(4) A, c = 16.015(3) A, beta = 109.546(10) degrees, V = 3115.47(11) A3, Z = 4, monoclinic, space group P2(1)/c, R1(all data) = 0.0850.

Phenotypic screening of mutations in Pmr1, the yeast secretory pathway Ca2+/Mn2+-ATPase, reveals residues critical for ion selectivity and transport

Thirty-five mutations were generated in the yeast secretory pathway/Golgi ion pump, Pmr1, targeting oxygen-containing side chains within the predicted transmembrane segments M4, M5, M6, M7, and M8, likely to be involved in coordination of Ca(2+) and Mn(2+) ions. Mutants were expressed in low copy number in a yeast strain devoid of endogenous Ca(2+) pumps and screened for loss of Ca(2+) and Mn(2+) transport on the basis of hypersensitivity to 1, 2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA) and Mn(2+) toxicity, respectively. Three classes of mutants were found: mutants indistinguishable from wild type (Class 1), mutants indistinguishable from the pmr1 null strain (Class 2), and mutants with differential sensitivity to BAPTA and Mn(2+) toxicity (Class 3). We show that Class 1 mutants retain normal/near normal properties, including (45)Ca transport, Golgi localization, and polypeptide conformation. In contrast, Class 2 mutants lacked any detectable (45)Ca transport; of these, a subset also showed defects in trafficking and protein folding, indicative of structural problems. Two residues identified as Class 2 mutants in this screen, Asn(774) and Asp(778) in M6, also play critical roles in related ion pumps and are therefore likely to be common architectural components of the cation-binding site. Class 3 mutants appear to have altered selectivity for Ca(2+) and Mn(2+) ions, as exemplified by mutant Q783A in M6. These results demonstrate the utility of phenotypic screening in the identification of residues critical for ion transport and selectivity in cation pumps.

Manganese selectivity of pmr1, the yeast secretory pathway ion pump, is defined by residue gln783 in transmembrane segment 6. Residue Asp778 is essential for cation transport

We have solubilized and purified the histidine-tagged yeast secretory pathway/Golgi ion pump Pmr1 to near homogeneity in one step, using nickel affinity chromatography. The purified pump demonstrates both Ca(2+)- and Mn(2+)-dependent ATP hydrolysis and phosphoenzyme intermediate formation in forward (ATP) and reverse (P(i)) directions. This preparation has allowed us to examine, in detail, the properties of mutations D778A and Q783A in transmembrane segment M6 of Pmr1. In phenotypic screens of Ca(2+) chelator and Mn(2+) toxicity reported separately (Wei, Y., Chen, J., Rosas, G., Tompkins, D.A., Holt, P.A., and Rao, R. (2000) J. Biol. Chem. 275, XXXX-XXXX), D778A was a loss-of-function mutant apparently defective for transport of both Ca(2+) and Mn(2+), whereas mutant Q783A displayed a differential sensitivity consistent with the selective loss of Mn(2+) transport. We show that mutant D778A is devoid of cation-dependent ATP hydrolytic activity and phosphoenzyme formation from ATP. However, reverse phosphorylation from P(i) is preserved but is insensitive to inhibition by Ca(2+) or Mn(2+) ions, which is evidence for a specific inability to bind cations in this mutant. We also show that Ca(2+) can activate ATP hydrolysis in the purified Q783A mutant, with a half-maximal concentration of 0.06 micrometer, essentially identical to that of wild type (0.07 micrometer). Mn(2+) activation of ATP hydrolysis was half-maximal at 0.02 micrometer in wild type, establishing a normal selectivity profile of Mn(2+) > Ca(2+). Strikingly, Mn(2+)-ATPase in the Q783A mutant was nearly abolished, even at concentrations of up to 10 micrometer. These results were confirmed in assays of phosphoenzyme intermediates. Molecular modeling of the packing between helices M4 and M6 suggests that residue Gln(783) in M6 may form a critical hydrophobic interaction with Val(335) in M4, such that the Ala substitution modifies the packing or tilt of the helices and thus the ion pore. The data emphasize the critical role of transmembrane segment M6 in defining the cation binding pocket of P-type ATPases.

Perinatal iron deficiency decreases cytochrome c oxidase (CytOx) activity in selected regions of neonatal rat brain

Intrauterine growth retardation and diabetes mellitus during human gestation result in significant losses of fetal and neonatal brain iron. Brain iron deficiency is associated with impaired cognitive processes including memory and attention. The regional distribution of iron staining and cytochrome c oxidase (CytOx) activity have not been mapped in the iron-sufficient or -deficient neonatal rat. CytOx is the iron-containing terminal enzyme in oxidative phosphorylation; its activity reflects neuronal metabolism. We hypothesized that neonatal brain iron deficiency differentially decreases iron and CytOx activity in brain regions, with more pronounced losses in structures involved in recognition memory. Pregnant Sprague Dawley rats were fed either an iron-deficient or -fortified diet from gestational d 1 until postnatal d 10. Iron staining and CytOx activity of 20 brain structures were mapped histochemically in 25 rats from each group. Brain iron staining was reduced from 75% to 100% and CytOx staining was decreased from 0% to 42% in the iron deficient group (p < 0.001). Areas with significantly reduced CytOx activity (p < 0.001) included all measured subareas of the hippocampus (CA1: 42%, CA3ab: 34%, CA3c: 33%, and dentate gyrus: 32%), the piriform cortex (17%), the medial dorsal thalamic nucleus (28%), and the cingulate cortex (41%). In contrast, the anterior thalamic nucleus, the lateral amygdaloid nucleus, and the medial habenula, areas not involved in higher cognitive functions, did not have significantly reduced CytOx activity (0%, 10%, and 16%, respectively). We conclude that perinatal iron deficiency differentially reduces neuronal metabolic activity, specifically targeting areas of the brain involved in memory processing.

Tracking of familial resemblance for resting blood pressure over time in the Québec Family Study

The etiology of familial resemblance for systolic (SBP) and diastolic (DBP) blood pressure, both within a single time point as well as across time points, was assessed to determine how familial etiologies underlying a trait may change across time. SBP and DBP measurements were taken roughly 12 years apart in family members participating in the longitudinal Québec Family Study. A longitudinal (bivariate) familial correlation model yields 3 types of correlations: intraindividual cross-time (e.g., father's BP at time 1 with his own BP at time 2); interindividual within-time (e.g., father time 1 with child time 1); and interindividual cross-time (e.g., father time 1 with child time 2). In addition, the change in BP across time (i.e., time 1-time 2) is examined using a univariate family correlation model. This combined method is useful in assessing the degree to which the same familial factors are operating across time (interindividual cross-time correlations), as well as the degree to which different heritable components are involved across time (change score). Maximal heritabilities for SBP were about 70% at each time point, while for DBP the heritability was larger at time 1 (87%) than time 2 (39%). Both the change scores (48% for SBP and 54% for DBP) and the cross-time comparisons (58% to 72% for SBP and 63% to 65% for DBP) evidenced significant familial resemblance. These results illustrate how simple methodologies can be used to specify how familial etiologies underlying a trait may change across time. For BP, the model includes unique familial factors that are specific to each time measurement, and an additional familial factor which is common to both time points. The factors leading to differences in longitudinal familial resemblance for BP (i.e., the unique factors) may be primarily genetic in origin, while those leading to stability across time may include both genetic and familial environmental effects. Sex and/or age interactions with the genotypes are also suggested.

Simultaneous determination of acidic and non-acidic pesticides in natural waters by liquid chromatography-mass spectrometry

There is increasing interest and demand for real multi-residue methods able to simultaneously determine pesticides with a broad spectrum of chemical characteristics in environmental and biological matrices. A method based on solid-phase extraction with a Carbograph 4 cartridge and liquid chromatography with electrospray mass spectrometry (LC-ES-MS) enabling simultaneous determination of non-acidic and acidic pesticides in real water samples is described. On repeatedly (n=5) extracting 4 l of drinking water (spike level 50 ng/l), 2 l of ground water (spike level 100 ng/l) and 1 l of river water (spike level 200 ng/l), recovery of 26 base/neutral pesticides and 13 acidic pesticides were equal to or better than 80%, except for carbendazim (67%), butocarboxim (73%), aldicarb (75%) and molinate (77%). Relative standard deviations ranged between 4 and 15%. Final extracts containing acidic and non-acidic pesticides were analyzed in a single chromatographic run while the ES-MS system was operated in both positive and negative ion modes. With the aim of finding the best operating conditions, in terms of sensitivity, the pH of the LC eluent was varied in the 2.9-8.4 range. Altogether, the best results were obtained by using an LC eluent containing 1 mmol/l formic acid. Over the entire pH range considered, well shaped peaks for both basic and acidic analytes were achieved by the use of a new generation LC column. By extracting selected ion current profiles from the total ion current mass chromatogram relative to analysis of 4 l of drinking water spiked with 50 ng/l of each of the 39 analytes, estimated limits of detection ranged between 0.05 and 1.5 ng/l, except for propyzamide (8 ng/l) and 2,4-DB (3 ng/l).

A search for susceptibility loci for anorexia nervosa: methods and sample description

BACKGROUND

Eating disorders have not traditionally been viewed as heritable illnesses; however, recent family and twin studies lend credence to the potential role of genetic transmission. The Price Foundation funded an international, multisite study to identify genetic factors contributing to the pathogenesis of anorexia nervosa (AN) by recruiting affective relative pairs. This article is an overview of study methods and the clinical characteristics of the sample.

METHODS

All probands met modified DSM-IV criteria for AN; all affected first, second, and third degree relatives met DSM-IV criteria for AN, bulimia nervosa (BN), or eating disorder not otherwise specified (NOS). Probands and affected relatives were assessed diagnostically with the Structured Interview for Anorexia and Bulimia. DNA was collected from probands, affected relatives and a subset of their biological parents.

RESULTS

Assessments were obtained from 196 probands and 237 affected relatives, over 98% of whom are of Caucasian ancestry. Overall, there were 229 relative pairs who were informative for linkage analysis. Of the proband-relative pairs, 63% were AN-AN, 20% were AN-BN, and 16% were AN-NOS. For family-based association analyses, DNA has been collected from both biological parents of 159 eating-disordered subjects. Few significant differences in demographic characteristics were found between proband and relative groups.

CONCLUSIONS

The present study represents the first large-scale molecular genetic investigation of AN. Our successful recruitment of over 500 subjects, consisting of affected probands, affected relatives, and their biological parents, will provide the basis to investigate genetic transmission of eating disorders via a genome scan and assessment of candidate genes.

Cerebrovascular disease and late life depression: an age old association revisited

OBJECTIVES

To examine the relationship between depression and cerebrovascular disease in three distinct settings: depression in established cerebrovascular disease, cerebrovascular disease in established depression and depression in vascular dementia.

METHODS

Medline, EMBASE, PsychLit and PsychInfo databases were scanned to locate relevant articles. Data were also extracted from other articles, cited by those articles generated from the above databases.

RESULTS

Using operational criteria, the prevalence of depression is higher than controls only within the first year after stroke, but most studies have not employed control groups. The prevalence of depression in vascular dementia compared with Alzheimer's disease is higher in the majority of studies, but matching for sociodemographic factors and severity of cognitive impairment has been inconsistent. An association between frontal/subcortical cerebrovascular lesions and depression in later life has been observed, but there may be methodological flaws underlying this observation in some computerized tomography studies.

CONCLUSION

There is some evidence that cerebrovascular disease has an aetiopathological role in late life depression. The increased likelihood of damage to frontal/subcortical brain circuitry following stroke, transient ischaemia and hypertension may explain the high prevalence of depression in older people with vascular risk factors. More valid definitions of lesion location and the use of appropriately matched control groups would seek to clarify this issue. The extrapolation to care settings from the high prevalence of depression accompanying cerebrovascular disease and the prolongation of disability in depressed people with stroke, suggests closer liaison between old age psychiatrists, neurologists and physicians caring for the elderly.