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A Papadimitriou

Publications and source records attributed to A Papadimitriou.

At least 19 recordsLinked to original sources
PubMed2007

Screening for SNCA and LRRK2 mutations in Greek sporadic and autosomal dominant Parkinson's disease: identification of two novel LRRK2 variants.

Mutations in SNCA and LRRK2 genes, encoding alpha-synuclein and leucine-rich repeat kinase 2, respectively, cause autosomal dominant Parkinson's disease (AdPD). The LRRK2 G2019S (c.6055G > A) and R1441G (c.4321C > G) mutations have also been identified in sporadic PD (sPD). We studied 55 unrelated patients with AdPD, 235 patients with sPD, and 235 healthy age- and gender-matched controls all of Greek origin. Patients with AdPD were screened for SNCA and LRRK2 mutations by direct sequencing. SNCA gene dosage analysis was also performed for AdPD using quantitative duplex polymerase chain reaction of genomic DNA. In addition, we investigated the frequency of the LRRK2 G2019S mutation in sPD. We found no missense mutations or multiplications in the SNCA gene. Here we report two novel variants, A211V (c.632C > T) and K544E (c.1630A > G) in LRRK2 gene in two patients with AdPD that was not present in controls. We identified only one patient with sPD (1/235; 0.4%) carrying the G2019S mutation. LRRK2 mutations are present in AdPD and sPD patients of Greek origin.

Adult↗
PubMed2006

Testing association between LRRK2 and Parkinson's disease and investigating linkage disequilibrium.

BACKGROUND: We and others recently identified the gene underlying PARK8 linked Parkinson's disease (PD). This gene, LRRK2, contains mutations that cause an autosomal dominant PD, including a mutation, G2019S, which is the most common PD causing mutation identified to date. Common genetic variability in genes that contain PD causing mutations has previously been implicated as a risk factor for typical sporadic disease. METHODS: We undertook a case-control association analysis of LRRK2 in two independent European PD cohorts using 31 tagging single nucleotide polymorphisms (tSNPs) and five potentially functional SNPs. To assess the structure of this locus in different populations, we have performed linkage disequilibrium (LD) analysis using these variants in a human diversity panel. RESULTS: We show that common genetic variability in LRRK2 is not associated with risk for PD in the European populations studied here. We also show inter-population variability in the strength of LD across this locus. CONCLUSIONS: To our knowledge this is the first comprehensive analysis of common variability within LRRK2 as a risk factor for PD.

Adult↗
PubMed2006

Positional nystagmus and vertigo due to a solitary brachium conjunctivum plaque.

The authors describe two patients suffering from demyelinating central nervous system disease who developed intense vertigo and downbeat nystagmus upon tilting their heads relative to gravity. Brain MRI revealed in both cases a single, small active lesion in the right brachium conjunctivum. The disruption of otolithic signals carried in brachium conjunctivum fibres connecting the fastigial nucleus with the vestibular nuclei is thought to be causatively involved, in agreement with a recently formulated model simulating central positional nystagmus. Insufficient otolithic information results in erroneous adjustment of the Listing's plane in off-vertical head positions, thus producing nystagmic eye movements.

Adult↗
PubMed2006

Association of tau haplotype-tagging polymorphisms with Parkinson's disease in diverse ethnic Parkinson's disease cohorts.

BACKGROUND: The overlap in the clinical and pathological features of tauopathies and synucleinopathies raises the possibility that the tau protein may be important in Parkinson's disease (PD) pathogenesis. Several MAPT polymorphisms that define the tau H1 haplotype have been investigated for an association with PD with conflicting results; however, two meta-analyses support an association between haplotype H1 and PD. METHODS: In this study, we recruited 508 patients and 611 healthy controls from Greek, Finnish and Taiwanese populations. We examined the possible genetic role of variation within MAPT in PD using haplotype-tagging single polymorphisms (SNPs) in these ethnically different PD populations. RESULTS: We identified a moderate association at SNP rs3785883 in the Greek cohort for both allele and genotype frequency (p = 0.01, p = 0.05, respectively) as well as for SNP rs7521 (genotype p = 0.02) and rs242557 (p = 0.01 genotypic, p = 0.04 allelic) in the Finnish population. There were no significant differences in genotype or allele distribution between cases and controls in the Taiwanese cohort. CONCLUSION: We failed to demonstrate a consistent association between the MAPT H1 haplotype (delineated by intron 9 ins/del) and PD in three ethnically diverse populations. However, the data presented here suggest that subhaplotypes of haplotype H1 may confer susceptibility to PD, and that either allelic heterogeneity or different haplotype composition explain the divergent haplotype results.

Adult↗
PubMed2006

The effect of inhaled budesonide on adrenal and growth suppression in asthmatic children.

The present authors evaluated adrenal reserve in asthmatic children on long-term inhaled corticosteroids and whether possible adrenal suppression could be predicted by growth retardation. Low-dose synacthen test (0.5 microg x 1.73 m(-2)) was performed in 72 asthmatic children with a median age of 9.4 (range 4.2-15.7) yrs on long-term treatment (median 18 (range 6-84) months) with low-to-moderate doses (median 363 (range 127-1012) microg x m(-2)) of inhaled budesonide, as well as in 30 controls. Adrenal suppression was considered as a peak serum cortisol <495 nmol x L(-1). The current authors calculated height standard deviation score (HSDS) at the time of testing and height velocity SDS (HVSDS) in the preceding year. Mean HSDS was 0.06+/-1.3 and HVSDS was -0.9+/-2.3. Adrenal suppression was disclosed in 15 asthmatic children (20.8%). There were no differences in HSDS and HVSDS between children with and without adrenal suppression. There was no correlation between peak cortisol response and dose or duration of treatment. However, a positive relationship between HVSDS and duration of treatment was noted. These data suggest that long-term treatment of asthmatic children with low and moderate doses of inhaled budesonide may result in mild adrenal suppression that cannot be predicted by growth deceleration. The negative influence of inhaled corticosteroids on growth becomes less the longer the duration of treatment.

Administration, Inhalation↗
PubMed2006

Serum S-100B protein as a biochemical marker of brain injury: a review of current concepts.

S-100 protein, described initially by Moore, constitutes a large family of at least 20 proteins with calcium binding ability. It is found as homo- or hetero-dimers of two different subunits (A and B). Types S-100AB and S-100BB are described as S-100B protein and are shown to be highly specific for nervous tissue. It is present in the cytosol of glial and Schwann cells, and also in adipocytes and chondrocytes, although in very low concentrations in the latter two. The role of protein S-100B is not yet fully understood. It is suggested that it has intracellular and extracellular neurotropic as well as neurotoxic function. At nanomolar levels, S-100B stimulates neurite outgrowth and enhances survival of neurons. However, at micromolar levels it stimulates the expression of inflammatory cytokines and induces apoptosis. Recently, serum S-100B protein has been proved to be an attractive surrogate marker of primary severe brain injury and secondary insults. It can be measured in the arterial and venous serum; it is not affected by haemolysis and remains stable for several hours without the need for immediate analysis. Its short half-life makes measurements crucial in the emergency and intensive care settings. This review summarises published findings on S-100B regarding its role as a serum biochemical marker of brain injury, i.e., after severe, moderate or mild neuro-trauma, subarachnoid haemorrhage, thrombo-embolic stroke, cerebral ischaemia and brain tumours, as well as extracranial trauma, neurodegenerative and psychiatric disorders.

Brain Injuries↗
PubMed2005

IL-1RN and IL-1B gene polymorphisms and cerebral hemorrhagic events after traumatic brain injury.

OBJECTIVE: To investigate the association of (variable number tandem repeat) interleukin (IL) 1RN and (-511) IL-1B gene polymorphisms with brain hemorrhagic events after traumatic brain injury (TBI). METHODS: Data from brain CT, Glasgow Coma Scale (GCS) at admission, and 6-month Glasgow Outcome Scale (GOS) and modified Rankin Scale (mRS) were collected for 151 prospectively recruited patients with TBI. IL-1RN and IL-1B genotypes were determined using standard methods. Presence vs absence of any type of brain hemorrhage was the main outcome. Type of brain hemorrhage, GCS at admission, and 6-month GOS and mRS were secondary outcomes. Odd ratios (ORs) and corresponding 95% CI were calculated using logistic regression analyses. In adjusted models, the associations were controlled for age, gender, diffuse brain edema, volume of intracranial hematoma, neurosurgical intervention, and GCS at admission. p values less than 0.01 were considered significant. RESULTS: Compared with noncarriers, IL-1RN allele 2 carriers had higher odds of having cerebral hemorrhages after TBI (adjusted OR = 4.57; 95% CI = 1.67 to 12.96; p = 0.004). The associations for (-511) IL-1B polymorphism were not significant. CONCLUSION: There is an association between the presence of interleukin-1RN allele 2 and posttraumatic brain hemorrhage.

Adult↗
PubMed2005

Motor signs predict poor outcomes in Alzheimer disease.

OBJECTIVE: To examine whether the presence of motor signs has predictive value for important outcomes in Alzheimer disease (AD). METHODS: A total of 533 patients with AD at early stages (mean Folstein Mini-Mental State Examination [MMSE] 21/30 at entry) were recruited and followed semiannually for up to 13.1 years (mean 3) in five University-based AD centers in the United States and European Union. Four outcomes, assessed every 6 months, were used in Cox models: cognitive endpoint (Columbia Mini-Mental State Examination < or = 20/57 [ approximately MMSE < or = 10/30]), functional endpoint (Blessed Dementia Rating Scale > or = 10), institutionalization equivalent index, and death. Using a standardized portion of the Unified PD Rating Scale (administered every 6 months for a total of 3,149 visit-assessments, average 5.9 per patient), the presence of motor signs, as well as of individual motor sign domains, was examined as time-dependent predictor. The models controlled for cohort, recruitment center, sex, age, education, a comorbidity index, and baseline cognitive and functional performance. RESULTS: A total of 39% of the patients reached the cognitive, 41% the functional, 54% the institutionalization, and 47% the mortality endpoint. Motor signs were noted for 14% of patients at baseline and for 45% at any evaluation. Their presence was associated with increased risk for cognitive decline (RR, 1.72; 95% CI, 1.24 to 2.38), functional decline (1.80 [1.33 to 2.45]), institutionalization (1.68 [1.26 to 2.25]), and death (1.38 [1.05 to 1.82]). Tremor was associated with increased risk for reaching the cognitive and bradykinesia for reaching the functional endpoints. Postural-gait abnormalities carried increased risk for institutionalization and mortality. Faster rates of motor sign accumulation were associated with increased risk for all outcomes. CONCLUSIONS: Motor signs predict cognitive and functional decline, institutionalization, and mortality in Alzheimer disease. Different motor sign domains predict different outcomes.

Aged↗
PubMed2005

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) in a Greek family.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an adult-onset inherited disease, characterised by recurrent strokes, migraine and cognitive impairment. We present the first Greek family with CADASIL, caused by the R153C mutation at exon 4 of the Notch3 gene. A member of this family carrying this mutation was also found to be heterozygotic for the MTHFR mutation, factor V Leiden mutation and had low serum levels of antithrombin III, thus resulting in the appearance of recurrent strokes and thrombotic episodes since his early adulthood. The co-existence of these thrombophilic disorders with CADASIL in a single person poses serious therapeutic dilemmas, as the administration of anticoagulant agents may correlate with increased risk of potentially fatal intracerebral haemorrhage.

Adult↗
PubMed2005

Reconsidering the sex differences in the incidence of pubertal disorders.

The age range of normal puberty is determined statistically; therefore, a similar percentage of boys and girls should present early or late puberty. However, far more girls present with precocious puberty and more boys with delayed puberty. We suggest that the gender differences in the incidence of pubertal disorders may be due to the following: The signs of puberty are more readily detected in girls, whereas male genitalia may not be examined during a physical examination. The description of the onset of puberty in boys is not uniform. The secular trend towards earlier pubertal maturation is more intense in girls than in boys. Therefore, there may be a fall in the age that correspond to the 3rd and 97th centiles for onset of puberty in girls while the ages at these centiles remain practically unchanged in boys. The high ratio of males to females with constitutional delay of puberty may also be attributed to the late appearance of the pubertal growth spurt in boys. The sex differences in the incidence of pubertal disorders may be due to gender dimorphism in the secular changes of pubertal maturation, to the difficulty of detecting the onset of puberty in boys and to the physiological sex differences in the timing of the pubertal growth spurt.

Adolescent↗
PubMed2005

Brain MRI and proton MRS findings in infants and children with respiratory chain defects.

OBJECTIVE: The aim of this study is to describe neuroimaging patterns in children with respiratory chain (RC) defects using magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (MRS) and to assess their role in the diagnostic evaluation. METHOD: Neuroimaging studies of 49 children (newborn to 15 years old) with biochemical evidence of RC defect were reviewed. Patients were divided in 3 groups ("definite" = 24, "probable" = 14, "possible" = 11) according to Modified Adult Criteria for the diagnosis of RC defect. Eighty-one MRI studies were reviewed for deep gray and white matter changes, degree of myelination, cerebral and cerebellar atrophy, and 67 proton MRS studies were assessed for the presence or absence of lactate elevation, as well as NAA/Cr ratio. The findings were compared among the 3 groups with chi-square test. RESULTS: All patients with "pure" myopathy had normal imaging studies. In patients with CNS involvement, significant differences in the frequency of imaging abnormalities among groups were found for deep gray matter (43 %/8 %/0 %; p = 0.01) and for the presence of lactate elevation on proton MRS (81 %/31 %/0 %; p = 0.001). CONCLUSION: Brain MRI and proton MRS abnormalities were observed only in association with clinical CNS involvement. Deep gray matter signal abnormalities on structural imaging and lactate elevation on proton MRS were more frequently observed in the "definite" group and represent neuroimaging markers for RC mitochondriopathy.

Aspartic Acid↗
PubMed2004

Motor signs during the course of Alzheimer disease.

BACKGROUND: Motor signs (MOSIs) are common in Alzheimer disease (AD) and may be associated with rates of cognitive decline, mortality, and cost of care. OBJECTIVE: To describe the progression and identify predictors of individual MOSIs in AD. METHODS: A cohort of 474 patients with AD at early stages was followed semiannually for up to 13.1 years (mean 3.6 years) in five centers in Europe and the United States. MOSIs were rated using a standardized portion of the Unified Parkinson's Disease Rating Scale. Overall, 3,030 visits/assessments of MOSIs (average 6.4/patient) were performed. Prevalence and incidence rates were calculated, and cumulative risk graphs were plotted for individual non-drug-induced MOSI domains. Rates of change over time taking into account potential covariates were also estimated. With use of each MOSI domain as outcome in Cox models, predictors of MOSI incidence were identified. RESULTS: At least one MOSI was detected in 13% of patients at first examination and in 36% for the last evaluation. Total MOSI score increased at an annual rate of 3% of total possible score. Rates of annual change for speech/facial expression (4%), rigidity (2.45%), posture/gait (3.9%), and bradykinesia (3.75%) were of similar magnitude, and their occurrence increased from first (3 to 6%) to last (22 to 29%) evaluation. Tremor was less frequent throughout the course of the disease (4% at first and 7% at last evaluation) and worsened less (0.75% increase/year). CONCLUSIONS: Most motor signs occur frequently and progress rapidly in Alzheimer disease. Tremor is an exception in that it occurs less frequently and advances at slower rates.

Aged↗
PubMed2004

Needle-knife suprapapillary sphincterotomy avoids postprocedure pancreatitis in patients with sphincter of Oddi dysfunction of biliary type II: a report of three cases.

We report the cases of three patients who fulfilled the criteria for sphincter of Oddi dysfunction of biliary type II and underwent needle-knife suprapapillary sphincterotomy. These patients presented with episodes of biliary-type pain after cholecystectomy and significant elevation of liver enzymes. Ultrasonography and MRI cholangiography revealed dilatation of the common bile duct, without visible stones. The patients all underwent needle-knife suprapapillary sphincterotomy because free cannulation of the common bile duct could not be achieved. Needle-knife suprapapillary sphincterotomy enabled catheterization of the common bile duct. After clearing of the common bile duct with a balloon catheter, no stones, fragments of stones, or sludge were observed to exit from the sphincterotomy. None of our patients developed postprocedure pancreatitis. When needle-knife suprapillary sphincterotomy is performed by an experienced biliary endoscopist, it is a safe and effective procedure for patients with sphincter of Oddi dysfunction of biliary type II, who otherwise constitute a high-risk group for the development of postsphincterotomy pancreatitis.

Catheterization↗
PubMed2004

Guillain-Barré syndrome in a patient with metastatic colon cancer receiving oxaliplatin-based chemotherapy.

We report Guillain-Barre syndrome (GBS), developed in a patient with metastatic colon cancer, receiving oxaliplatin-based chemotherapy. The 53-year-old patient was treated with first-line chemotherapy consisting of oxaliplatin 45 mg/m2, 5-fluorouracil 450 mg/m2 and folinic acid 200 mg/m2, all given on the same day in a weekly schedule. After 13 weeks of treatment and a cumulative oxaliplatin dose of 585 mg/m2, the patient developed unsteadiness of gait, dysphagia, and weakness of both the upper and lower limbs, as well as impairment of all sensory modalities. Clinical examination, computed tomography and magnetic resonance imaging scans of the brain, blood tests, nerve conduction studies, and cerebrospinal fluid analysis confirmed the diagnosis of GBS. Intravenous immunoglobulin G was administered for 5 days and the patient recovered fully. Oxaliplatin can cause acute and delayed neurotoxicity, but this is the first report of GBS in a patient receiving oxaliplatin-based chemotherapy. Elevation of pro-inflammatory cytokines, such as tumor necrosis factor-alpha and interleukin-6, induced by oxaliplatin, may represent the relevant causal links involved in the cascade of events which have led to the immune-mediated demyelination in the peripheral nervous system in this patient.

Adenocarcinoma↗
PubMed2004

Autonomic neuropathy and gastrointestinal motility disorders in children and adolescents with type 1 diabetes mellitus.

INTRODUCTION: There is little information on the gastrointestinal motility abnormalities and autonomic neuropathy of children with gastrointestinal symptoms and type 1 diabetes mellitus (T1DM). METHODS: The authors studied 33 consecutive patients (mean age, 15.3 years; 13 males) with T1DM (median duration, 7.7 years) attending the outpatient clinic because of chronic dyspepsia (CD; n = 14), or chronic constipation (CC; n = 19), and 48 consecutive non-T1DM patients (mean age, 13.7 years; 18 males), who presented with similar symptoms (18 with CD; 30 with CC). Fasting serum motilin concentrations and cardiovascular autonomic function tests (CAFT) were assessed and compared with those of age- and gender-matched healthy control subjects. Gastric emptying half time (GE t1/2) of a solid meal and mouth-to-anus transit time (MATT) were measured in patients with CD and CC, respectively. RESULTS: CAFT was comparable between patients with T1DM and healthy control subjects. GE t1/2 and MATT were not different between T1DM patients and non-T1DM patients with CD and CC, respectively. However, a marginally significant positive correlation was found in the patients with T1DM between GE t1/2 and blood glucose concentrations (R = 0.54; P = 0.08). In addition, serum motilin concentrations were significantly lower in patients with T1DM compared with healthy control subjects (P < 0.0005), and in patients with T1DM and higher serum glucose concentrations compared with those with lower serum glucose concentrations (P = 0.03). CONCLUSION: Autonomic neuropathy is not an etiological factor of gastrointestinal symptoms in children and adolescents with diabetes. Mild or moderate hyperglycemia does not affect gastrointestinal motility.

Adolescent↗
PubMed2004

Protein misfolding in neurodegenerative diseases.

A common pathogenic mechanism shared by diverse neurodegenerative disorders, like Alzheimer's disease, Parkinson's disease, Huntington's disease and transmissible spongiform encephalopathies, may be altered protein homeostasis leading to protein misfolding and aggregation of a wide variety of different proteins in the form of insoluble fibrils. Mutations in the genes encoding protein constituents of these aggregates have been linked to the corresponding diseases, thus a reasonable scenario of pathogenesis was based on misfolding of a neurone-specific protein that forms insoluble fibrils that subsequently kill neuronal cells. However, during the past 5 years accumulating evidence has revealed the neurotoxic role of prefibrillar intermediate forms (soluble oligomers and protofibrils) produced during fibril formation. Many think these may be the predominant neurotoxic species, whereas microscopically visible fibrillar aggregates may not be toxic. Large protein aggregates may rather be simply inactive, or even represent a protective state that sequesters and inactivates toxic oligomers and protofibrils. Further understanding of the biochemical mechanisms involved in protein misfolding and fibrillization may optimize the planning of common therapeutic approaches for neurodegenerative diseases, directed towards reversal of protein misfolding, blockade of protein oligomerization and interference with the action of toxic proteins.

Alzheimer Disease↗
PubMed2004

Frontal brain lobe impairment in obstructive sleep apnoea: a proton MR spectroscopy study.

Patients with obstructive sleep apnoea syndrome frequently have cognitive deficits, especially related to executive functions, which cannot be fully explained by daytime sleepiness and are partial irreversible after nasal continuous positive airway pressure treatment. The causal mechanism of these cognitive deficits is not yet known, but it has been proposed that they are associated with chemical and structural brain cell injury. The aim of this study was to investigate brain metabolism in patients with sleep apnoea syndrome. Twenty-two patients with severe sleep apnoea and 10 healthy volunteers of comparable age were studied using single voxel proton magnetic resonance spectroscopy. Magnetic resonance spectra were obtained from prefrontal cortex, parieto-occipital and frontal periventricular white matter. N-acetylaspartate-to-creatine and choline-to-creatine ratios were significantly lower in the frontal white matter of obstructive sleep apnoea patients when compared to controls. Absolute concentrations of N-acetylaspartate and choline were also significantly reduced in the frontal white matter of patients with sleep apnoea. Frontal lobe white matter lesions are known to be associated with cognitive executive dysfunction. The findings of this study may offer an explanation for the sometimes irreversible cognitive deficits associated with sleep apnoea.

Adult↗