Surprisal From Language Models Can Predict ERPs in Processing Predicate-Argument Structures Only if Enriched by an Agent Preference Principle

Language models based on artificial neural networks increasingly capture key aspects of how humans process sentences. Most notably, model-based surprisals predict event-related potentials such as N400 amplitudes during parsing. Assuming that these models represent realistic estimates of human linguistic experience, their success in modeling language processing raises the possibility that the human processing system relies on no other principles than the general architecture of language models and on sufficient linguistic input. Here, we test this hypothesis on N400 effects observed during the processing of verb-final sentences in German, Basque, and Hindi. By stacking Bayesian generalised additive models, we show that, in each language, N400 amplitudes and topographies in the region of the verb are best predicted when model-based surprisals are complemented by an Agent Preference principle that transiently interprets initial role-ambiguous noun phrases as agents, leading to reanalysis when this interpretation fails. Our findings demonstrate the need for this principle independently of usage frequencies and structural differences between languages. The principle has an unequal force, however. Compared to surprisal, its effect is weakest in German, stronger in Hindi, and still stronger in Basque. This gradient is correlated with the extent to which grammars allow unmarked NPs to be patients, a structural feature that boosts reanalysis effects. We conclude that language models gain more neurobiological plausibility by incorporating an Agent Preference. Conversely, theories of human processing profit from incorporating surprisal estimates in addition to principles like the Agent Preference, which arguably have distinct evolutionary roots.

Predictors of Nursing Home Placement in a Cohort of European People with Alzheimer's Disease and Other Dementia Cases Enrolled in SCU-B or Non SCU-B Centers: The RECage Study

Background

Nursing home placement (NHP) can be the final step of patients with Alzheimer's disease.

Objective

We aimed to identify NHP predictors among 508 people with dementia with a 3-year follow-up.

Methods

We analyzed data from the international observational RECage study, involving 508 people with especially Alzheimer's disease and comparing a cohort enrolled by five centers with a Special Care Unit for BPSD (behavioral and psychological symptoms of dementia) and another one enrolled by six centers lacking this facility. The tertiary objective of the study was to assess the possible role of the SCU-B in delaying NHP. We assessed the relationship of the baseline characteristics with NHP by means of univariate analysis followed by Cox's multivariate model.

Results

Patients' mean age was 78.1 years, 54.9% were women. Diagnosis mean age was 75.4 (±8.32) years; the main diagnosis was Alzheimer's disease (296; 58.4%). During follow-up, 96 (18.9%) patients died and 153 (30.1%) were institutionalized without a statistically significant difference between the two cohorts (p = 0.9626). The mean NHP time was 902 (95% CI: 870-934). The multivariable analysis without death as a competing risk retained four independent predictors of NHP: age increase (hazard ratio (HR) = 1.023, 95% CI: 1.000-1.046), patient education level increase (HR = 1.062, 95% CI: 1.024-1.101), Neuropsychiatric Inventory total increase (HR = 1.018; 95% CI: 1.011-1.026), and total Mini-Mental State Examination as a favorable factor (HR = 0.948, 95% CI: 0.925-0.971). Gender (females versus males: HR = 1.265, 95% CI: 0.899-1.781) was included in the final Cox's model for adjusting the estimates for.

Conclusions

Our data partially agree with the predictors of NHP in literature including the effect of high education level. No caregivers' factors were statistically significant.

Clinical trial registration

NCT03507504.

Long-Term Treatment Over 52 Weeks with Monthly Fremanezumab in Drug-Resistant Migraine: A Prospective Multicenter Cohort Study

BACKGROUND

Real-world studies on fremanezumab, an anti-calcitonin gene-related peptide monoclonal antibody for migraine prevention, are few and with limited follow-up.

OBJECTIVE

We aimed to evaluate the long-term (up to 52 weeks) effectiveness and tolerability of fremanezumab in high-frequency episodic migraine and chronic migraine.

METHODS

This s an independent, prospective, multicenter cohort study enrolling outpatients in 17 Italian Headache Centers with high-frequency episodic migraine or chronic migraine and multiple preventive treatment failures. Patients were treated with fremanezumab 225 mg monthly. The primary outcomes included changes from baseline (1 month before treatment) in monthly headache days, response rates (reduction in monthly headache days from baseline), and persistence in medication overuse at months 3, 6, and 12 (all outcome timeframes refer to the stated month). Secondary outcomes included changes from baseline in acute medication intake and disability questionnaires scores at the same timepoints. A last observation carried forward analysis was also performed.

RESULTS

A total of 90 patients who received at least one dose of fremanezumab and with a potential 12-month follow-up were included. Among them, 15 (18.0%) patients discontinued treatment for the entire population, a reduction in monthly headache days compared with baseline was reported at month 3, with a significant median [interquartile range] reduction in monthly headache days (- 9.0 [11.5], p < 0.001). A statistically different reduction was also reported at month 6 compared with baseline (- 10.0 [12.0]; p < 0.001) and at 12 months of treatment (- 10.0 [14.0]; p < 0.001). The percentage of patients with medication overuse was significantly reduced compared with baseline from 68.7% (57/83) to 29.6% (24/81), 25.3% (19/75), and 14.7% (10/68) at 3, 6, and 12 months of treatment, respectively (p < 0.001). Acute medication use (days and total number) and disability scores were also significantly reduced (p < 0.001). A ≥ 50% response rate was achieved for 51.9, 67.9, and 76.5% of all patients at 3, 6, and 12 months, respectively. Last observation carried forward analyses confirmed these findings. Fremanezumab was well tolerated, with just one patient discontinuing treatment because of adverse events.

CONCLUSIONS

This study provides evidence for the real-world effectiveness of fremanezumab in treating both high-frequency episodic migraine and chronic migraine, with meaningful and sustained improvements in multiple migraine-related variables. No new safety issue was identified.

Incidence and Long-term Functional Outcome of Neurologic Disorders in Hospitalized Patients With COVID-19 Infected With Pre-Omicron Variants

BACKGROUND AND OBJECTIVES

A variety of neurologic disorders have been reported as presentations or complications of coronavirus disease 2019 (COVID-19) infection. The objective of this study was to determine their incidence dynamics and long-term functional outcome.

METHODS

The Neuro-COVID Italy study was a multicenter, observational, cohort study with ambispective recruitment and prospective follow-up. Consecutive hospitalized patients presenting new neurologic disorders associated with COVID-19 infection (neuro-COVID), independently from respiratory severity, were systematically screened and actively recruited by neurology specialists in 38 centers in Italy and the Republic of San Marino. The primary outcomes were incidence of neuro-COVID cases during the first 70 weeks of the pandemic (March 2020-June 2021) and long-term functional outcome at 6 months, categorized as full recovery, mild symptoms, disabling symptoms, or death.

RESULTS

Among 52,759 hospitalized patients with COVID-19, 1,865 patients presenting 2,881 new neurologic disorders associated with COVID-19 infection (neuro-COVID) were recruited. The incidence of neuro-COVID cases significantly declined over time, comparing the first 3 pandemic waves (8.4%, 95% CI 7.9-8.9; 5.0%, 95% CI 4.7-5.3; 3.3%, 95% CI 3.0-3.6, respectively; p = 0.027). The most frequent neurologic disorders were acute encephalopathy (25.2%), hyposmia-hypogeusia (20.2%), acute ischemic stroke (18.4%), and cognitive impairment (13.7%). The onset of neurologic disorders was more common in the prodromic phase (44.3%) or during the acute respiratory illness (40.9%), except for cognitive impairment whose onset prevailed during recovery (48.4%). A good functional outcome was achieved by most patients with neuro-COVID (64.6%) during follow-up (median 6.7 months), and the proportion of good outcome increased throughout the study period (r = 0.29, 95% CI 0.05-0.50; p = 0.019). Mild residual symptoms were frequently reported (28.1%) while disabling symptoms were common only in stroke survivors (47.6%).

DISCUSSION

Incidence of COVID-associated neurologic disorders decreased during the prevaccination phase of the pandemic. Long-term functional outcome was favorable in most neuro-COVID disorders, although mild symptoms commonly lasted more than 6 months after infection.

BPSD Patterns in Patients With Severe Neuropsychiatric Disturbances: Insight From the RECAGE Study

OBJECTIVE

Behavioral and psychological symptoms of dementia (BPSD) profiles vary depending on etiology in patients with mild-to-moderate BPSD. It is not known if similar differences exist in patients with severe BPSD.

METHODS

We analyzed data collected at baseline in 398 patients with severe BPSD (NPI ≥ 32) and defined diagnosis of dementia (Alzheimer's disease [AD] 297; frontotemporal dementia [FTD] 39; Lewy body disease/Parkinsonian dementia [LBD/PD] 31; and vascular dementia [VD] 31) included in the European multicenter cohort RECAGE.

RESULTS

Mean total NPI was 52.11 (18.55). LBD/PD patients demonstrated more hallucinations, more anxiety and more delusions than patients with other dementia. FTD patients had less delusions and more disinhibition than patients with other neurodegenerative disorders. These profiles overlapped partially with those reported in the literature in patients with less severe symptoms.

CONCLUSION

Patients with severe BPSD display different and specific profiles of neuropsychiatric symptoms depending on dementia etiology.

A Confirmatory and an Exploratory Factor Analysis of the Cohen-Mansfield Agitation Inventory (CMAI) in a European Case Series of Patients with Dementia: Results from the RECage Study

BACKGROUND

One of the most widely used instruments for assessing agitation in dementia patients is the Cohen-Mansfield Agitation Inventory (CMAI), nevertheless no global score has been proposed. The aim of this study is: (a) to conduct a confirmatory (CFA) and exploratory factor analysis (EFA) of CMAI on people with dementia and Psychological and Behavioral Symptoms (BPSD), and (b) to propose an alternative structure, based on clinical criteria including all CMAI items.

METHODS

Confirmatory and exploratory factor analyses were carried out on the CMAI 29 items administered at baseline to 505 patients with dementia (PwD) and BPSD enrolled in the international observational RECage study.

RESULTS

The three-factor structure has not been confirmed by the CFA, whilst the EFA was carried out respectively on 25 items disregarding 4 items with a prevalence ≤5% and then on 20 items disregarding 9 items with a prevalence ≤10%. The four-factor structure explaining 56% of the variance comprised Physically Aggressive behavior, Verbally Aggressive behavior, Physically non-aggressive behavior, and Physically and verbally aggressive behavior.

CONCLUSIONS

A new grouping of all items according to a clinical criterion is proposed, allowing for a more sensible evaluation of the symptoms leading to better differentiation.

Eye-to-Hand Coordination in Obstructive Sleep APNEA Syndrome: a Descriptive Study

OBJECTIVE

Psychomotor slowdown was observed in individuals with Obstructive Sleep Apnea Syndrome (OSAS). Previous studies evaluated separately cognitive and motor reaction times, finding that OSAS individuals show a specific impairment in the latter. The present study investigates whether eye-to-hand coordination (EHC), a specific psychomotor ability, is compromised in OSAS.

METHOD

The EHC was measured in 30 OSAS individuals who were matched with 30 healthy controls by the Two-Hand Coordination Test analyzing the speed, accuracy, and coordination; the role of these variables was investigated in predicting the group they belonged to.

RESULTS

The OSAS participants showed poorer performance in the execution accuracy (t(55) = -3.36, d'Cohen = -0.89, p ≤ .001), which was also found to be the only predictor of the belonging to group (β = 0.43 (0.18), p < .05).

CONCLUSIONS

The OSAS individuals show impairments in EHC and in correcting their error (executive slowdown). This is the first investigation exploring EHC coordination in this population and contributes in understanding the psychomotor slowness characterizing OSAS.

Respectful Caring for the Agitated Elderly (ReCAGE): A Multicentre, Prospective, Observational Study to Evaluate the Effectiveness of Special Care Units for People with Dementia

BACKGROUND

Behavioral and psychological symptoms of dementia (BPSD) bring complexity in the clinical management of people with dementia; therefore, it is important to evaluate different models of care, such as Special Care Units (SCU-B).∥Objective:To evaluate the SCU-B effectiveness toward alleviating BPSD and improving the quality of life (QoL) of patients and their caregivers.∥Methods:ReCAGE was a multicenter, controlled, longitudinal study where 508 patients with BPSD were enrolled in two cohorts: 262 patients from centers endowed with a SCU-B, and 246 from centers without SCU-B. Statistical analyses included factorial ANCOVA for comparison among centers. The primary endpoint was effectiveness of the SCU-B, measured through the Neuropsychiatric Inventory (NPI) changes. Secondary endpoints were change in QoL of patients and caregivers, and the tertiary endpoint was time to nursing home admission.∥Results:The NPI scores decreased in both arms, with a statistically significant difference from baseline to 36 months (p < 0.0001) in both cohorts. Over time, NPI decreased more steeply during the first year in the SCU-B arm, but in the following two years the slope was clearly in favor of the control arm. This different pattern of the two cohorts reached statistical significance at the interaction "cohort by time" (p < 0.0001). Conflicting results were found regarding the outcomes of quality of life, while there were no differences in time to institutionalization in both cohorts.∥Conclusion:The RECage study did not confirm the long-term superiority of the pathway comprising a SCU-B. A post-hoc analysis revealed data supporting their acute effectiveness during behavioral crises.

Beyond the Benchmarks: Toward Human-Like Lexical Representations

To process language in a way that is compatible with human expectations in a communicative interaction, we need computational representations of lexical properties that form the basis of human knowledge of words. In this article, we concentrate on word-level semantics. We discuss key concepts and issues that underlie the scientific understanding of the human lexicon: its richly structured semantic representations, their ready and continual adaptability, and their grounding in crosslinguistically valid conceptualization. We assess the state of the art in natural language processing (NLP) in achieving these identified properties, and suggest ways in which the language sciences can inspire new approaches to their computational instantiation.

P1402 The behavior of regional longitudinal strain depends on the coronary reserve in a simultaneous analysis during Dipyridamol Stress Echocardiography Test

Objectives

Compare the behavior of the Apical LS and GLS with the value of the CFR in the LADA and as a secondary objective to compare these responses with a simultaneous visual analysis of the motility during EchoDipi.

Materials and methods

179 patients (p) were included (age 68.7 ± 7 years). Of them, 113p(65%) were men. At the peak of the effect of Dipi(0.84mg/kg in 4m) the CFR was measured in the distal region of the LADA(Normal Value≥2). The subjects were divided into 2 groups(G): G1: p with CFR of the LAD≥2 and G2 p with LADA CFR &lt; 2. ApRLS was defined as the average of the 4 apical segments, in 4, 3 and 2 apical views, considering any increase in the percentage of deformation as normal. The LGS and wall motility of the 17 segments were evaluated; p with LBBB or wall motion abnormalities were excluded.

Results

Of 179 p, 113p(63.12%) were included in G1 and 66p(36.87%) in G2. G1 were older(65.9 ± 10.27 vs 72.2 ± 9.31,p &lt; 0.02), without significant differences in other clinical characteristics. No differences in the values of LGS and the Ap RLS at rest between G1 and G2 (GLS: G1: -19.8 ± 4.8 vs G2: -20.27 ± 2.6 p = NS; Ap RLS G1: -25.41 ± 4.75 vs G2: -26.73 ± 7.6 p = NS). During EchoDipi GLS and Ap RLS increased in the pts of G1 with a significant worsening in the G2 (SLG: G1: -22.98 ± 4.31 vs G2: -17.82 ± 2.70, p &lt; 0.0001; Ap SLR G1: -28.43 ± 5.6 vs. G2: -22.78 ± 7.41, p &lt; 0.0001). We observed that in 96.7% of p G1 the ApRLS increased strain with the stress meanwhile 95.31% of the G2 decrease(p &lt; 0.0001). Negative predictive value (NPV) :95.6%(CI = 87.8-98.5%), positive predictive value (PPV) =96.8%(CI = 89.0-99.1%).Specificity(E): 97%(CI = 89.9-99.2%),Sensibility(S): 95.2%(CI = 86.9-98.4%). Area Under the ROC curve(AUC)=0.92. The behavior of the GLS showed that 82.8% of the pts of the G1 during EchoDipi increased their Strain values in contrast with 78.8% p of the G2 decrease p &lt; 0.01).NPV 78.8%(CI = 67.5-86.9%),PPV:90.8%(CI = 83.9-94.9%),E:83.9% (CI = 72.8-91.0%),S:87.6%(CI = 80.3-92.5%).AUC ROC= 0.84. The analysis of wall motility showed that 96.46%(109p) of G1 had preserved wall motility, 1 p showed contractility abnormalities and decreased ApRLS. Of the G2, 36p showed conserved contractility during the stress.

Conclusions.There was a close correlation between LADA coronary flow reserve and the contractile reserve evaluated by regional longitudinal strain of the 4 apical segments, which was superior to the use of global longitudinal strain. The Apical Strain showed a better correlation with the LADA coronary flow reserve than with the visual analysis of wall motion.

Autophagy Regulates the Liver Clock and Glucose Metabolism by Degrading CRY1

The circadian clock coordinates behavioral and circadian cues with availability and utilization of nutrients. Proteasomal degradation of clock repressors, such as cryptochrome (CRY)1, maintains periodicity. Whether macroautophagy, a quality control pathway, degrades circadian proteins remains unknown. Here we show that circadian proteins BMAL1, CLOCK, REV-ERBα, and CRY1 are lysosomal targets, and that macroautophagy affects the circadian clock by selectively degrading CRY1. Autophagic degradation of CRY1, an inhibitor of gluconeogenesis, occurs in a diurnal window when rodents rely on gluconeogenesis, suggesting that CRY1 degradation is time-imprinted to maintenance of blood glucose. High-fat feeding accelerates autophagic CRY1 degradation and contributes to obesity-associated hyperglycemia. CRY1 contains several light chain 3 (LC3)-interacting region (LIR) motifs, which facilitate the interaction of cargo proteins with the autophagosome marker LC3. Using mutational analyses, we identified two distinct LIRs on CRY1 that exert circadian glycemic control by regulating CRY1 degradation, revealing LIRs as potential targets for controlling hyperglycemia.

[Mandibular repositioning in adult patients. An alternative to surgery in some patients? A two-year follow-up]

INTRODUCTION

A number of adult patients with skeletal discrepancies refuse surgical intervention.

AIMS

The aim was to assess the reaction to mandibular repositioning in simulating a skeletal correction in such patients.

MATERIALS AND METHODS

32 consecutive patients without any signs of temporo-mandibular dysfunction (TMD) were offered mandibular repositioning, as a non-invasive alternative and it was explained to them that the approach was based on the results described in case reports. Before initiating any treatment initial records, headfilms, study casts and photos were taken (T₀) and the mandible was repositioned to camouflage the skeletal discrepancy by means of an occlusal built-up in Triad^® Gel.

RESULTS

Three months later (T₁) 23 patients had adapted to the new occlusion reflected in absence of functional problems and lack of fracture of the built-up. In these patients the mandibular position was maintained by orthodontics adjusting the occlusion to the built-up position (T₁). The skeletal changes occurring during repositioning were assessed on sagittal and frontal head films while intra-articular changes occurring during a 2-year follow-up period (T₂) were evaluated on images constructed from CBCT images. No significant changes, neither in the direction of a relapse nor in the direction of further normalization of the condylar positioning, were observed during the 2-year observation period.

CONCLUSIONS

Repositioning is a non-invasive intervention and may be considered a valid alternative to surgery in some patients. Morphological variables from the radiographs taken at T₀ and the results of the initial clinical evaluation of dysfunction yielded only vague and insignificant indications regarding the predictability of adaptation to the repositioning.

Long-Term Nicergoline Treatment of Mild to Moderate Senile Dementia : Results of a Multicentre, Double-Blind, Placebo-Controlled Study

The efficacy and tolerability of nicergoline were evaluated in a long-term, double-blind, placebo-controlled trial. 108 patients, fulfilling DSM III-R criteria for mild to moderate senile dementia of degenerative, vascular or mixed origin, were selected from a pool of outpatients attending five Italian neurological centres and randomised to receive nicergoline 30mg twice daily (54 patients) or placebo (54 patients) for 12 months. Treatment efficacy on cognitive and behavioural performances was assessed by the Sandoz Clinical Assessment Geriatric scale (SCAG) and Mini Mental State Examination (MMSE), at baseline and after 3, 6, 9 and 12 months of treatment. Investigators and patients or caregivers provided a global evaluation of treatment outcome at study end. The efficacy analysis was carried out on 101 patients (51 nicergoline; 50 placebo) who completed the 12-month study. At study end, the SCAG total score and its clusters showed statistically significant improvement in the nicergoline-treated group compared with placebo-treated patients. The MMSE total score was maintained with nicergoline treatment. Global treatment evaluations, both by physician and patients, were consistently in favour of nicergoline (p < 0.001). Nicergoline was well tolerated; incidence of adverse events (7% in the nicergoline and 2% in the placebo group), withdrawals and haemodynamic changes were comparable with placebo.

Autophagy in the CNS and Periphery Coordinate Lipophagy and Lipolysis in the Brown Adipose Tissue and Liver

The integrative physiology of inter-organ communication in lipophagy regulation is not well understood. Lipophagy and the cytosolic lipases ATGL and HSL contribute to lipid droplet (LD) mobilization; however, whether autophagy proteins engage with lipases to promote lipid utilization remains unknown. Here, we show that cold induces autophagy in proopiomelanocortin (POMC) neurons and activates lipophagy in brown adipose tissue (BAT) and liver in mice. Targeted activation of autophagy in POMC neurons via intra-hypothalamic rapamycin is sufficient to trigger lipid utilization in room temperature-housed mice. Conversely, inhibiting autophagy in POMC neurons or in peripheral tissues or denervating BAT blocks lipid utilization. Unexpectedly, the autophagosome marker LC3 is mechanistically coupled to ATGL-mediated lipolysis. ATGL exhibits LC3-interacting region (LIR) motifs, and mutating a single LIR motif on ATGL displaces ATGL from LD and disrupts lipolysis. Thus, cold-induced activation of central autophagy activates lipophagy and cytosolic lipases in a complementary manner to mediate lipolysis in peripheral tissues.

Prolonged Pseudohypoxia Targets Ambra1 mRNA to P-Bodies for Translational Repression

Hypoxia has been associated with several pathological conditions ranging from stroke to cancer. This condition results in the activation of autophagy, a cyto-protective response involving the formation of double-membraned structures, the autophagosomes, in the cytoplasm. In this study, we investigated the cellular mechanisms regulating the autophagy gene Ambra1, after exposure to a hypoxia mimetic, cobalt chloride (CoCl2). We observed that, upon CoCl2 administration, activation of the apoptotic machinery was concomitant with down-regulation of the pro-autophagic factor Ambra1, without affecting transcription. Additionally, co-treating the cells with the caspase inhibitor z-VAD-FMK did not restore Ambra1 protein levels, this implying the involvement of other regulatory mechanisms. Partial re-localization of Ambra1 mRNA to non-translating fractions and cytoplasmic P-bodies was further detected. Thus, in this pseudohypoxic context, Ambra1 mRNA translocation to P-bodies and translational suppression correlated with increased cell death.

Craniofacial growth and respiration: a study on an animal model

AIMS

The aim of this study was to analyse the effects of nasal obliteration with regards to the linear dimensions of dissected hemimandibles of a homogeneous sample of young rats.

METHODS

68 pure breed male Sprague-Dawley rats, aged four weeks, were divided into four groups of 17: two control groups and two test groups. The first control group was sacrificed at the beginning of the observation period and the other one at the end. The test groups, one of which had the right nostril occluded by silicon material while the other had the left occluded, were sacrificed after eight weeks, at twelve weeks. After isolating the hemi-mandibles, four vertical and four sagittal measurements were taken; comparison was then made between the control groups and the experimental groups. The sagittal measurements are articular surface of the condyle-neck incisor (SARCIN), articular surface of the condyle-mental foramen (SARFORO), articular surface of the condyle-margo incisalis (SARMI), articular surface of the condyle-surface mesial of the first molar (SARSMM). The vertical measurements are superior condyle surface-base (SCOSUB), mesial surface of the first molar-base (SUMESM), maximum inferior arched concavity-base, (XCOARIB), maximum sigmoid notch concavity-base (XCOINSB).

RESULTS

The sagittal and vertical measurements showed an increase in the values of the experimental group when compared to the controls.

CONCLUSION

An altered nasal respiration is able to influence the patterns of facial growth and in particular to induce an increase in the growth of the mandible.

A neuroprotective role for the DNA damage checkpoint in tauopathy

ATM and p53, effectors of the DNA damage checkpoint, are generally considered pro-apoptotic in neurons. We show that DNA damage and checkpoint activation occurs in postmitotic neurons in animal models of tauopathy, neurodegenerative disorders that include Alzheimer's disease. Surprisingly, checkpoint attenuation potently increases neurodegeneration through aberrant cell cycle re-entry of postmitotic neurons. These data suggest an unexpected neuroprotective role for the DNA damage checkpoint in tauopathies.

Impact of gender differences on the outcome of Alzheimer's disease

BACKGROUND AND AIMS

Since little is known about the role of gender in the course of Alzheimer's disease (AD), a prospective epidemiological study was conducted to detect gender differences in relation to AD evolution and outcome.

METHODS

Six hundred AD patients, 214 men and 386 women, first seen between September 2000 and December 2003, were enrolled; the follow-up period lasted until December 2008.

RESULTS

The men had greater comorbidity and higher mortality than the women, who instead recorded more disability and longer survival. Survival curves showed that women reach partial loss of autonomy faster than men. Higher Neuropsychiatric Inventory scores at baseline showed a predictive value for loss of autonomy regardless of gender. Pharmacological treatment seems to have a protective role on disability and mortality.

CONCLUSIONS

Gender influences disease evolution not only directly but also through other factors such as comorbidity.

p73 and p63 sustain cellular growth by transcriptional activation of cell cycle progression genes

Despite extensive studies on the role of tumor suppressor p53 protein and its homologues, p73 and p63, following their overexpression or cellular stress, very little is known about the regulation of the three proteins in cells during physiologic cell cycle progression. We report a role for p73 and p63 in supporting cellular proliferation through the transcriptional activation of the genes involved in G(1)-S and G(2)-M progression. We found that in MCF-7 cells, p73 and p63, but not p53, are modulated during the cell cycle with a peak in S phase, and their silencing determines a significant suppression of proliferation compared with the control. Chromatin immunoprecipitation analysis shows that in cycling cells, p73 and p63 are bound to the p53-responsive elements (RE) present in the regulatory region of cell cycle progression genes. On the contrary, when the cells are arrested in G(0)-G(1), p73 detaches from the REs and it is replaced by p53, which represses the expression of these genes. When the cells move in S phase, p73 is recruited again and p53 is displaced or is weakly bound to the REs. These data open new possibilities for understanding the involvement of p73 and p63 in cancer. The elevated concentrations of p73 and p63 found in many cancers could cause the aberrant activation of cell growth progression genes and therefore contribute to cancer initiation or progression under certain conditions.

Persistent trigeminal artery causing "double" neurovascular conflict

We report the case of a 73-year-old woman who presented with right VI nerve palsy and homolateral atypical trigeminal neuralgia; standard neuroradiological investigation of orbital/retroorbital regions and intracranial arteries excluded the most commonly demonstrable underlying causes while brain magnetic resonance (T1-weighted fat suppression; T2-weighted thin-section) and magnetic resonance angiography disclosed the evidence of "double" neurovascular conflict because of persistent trigeminal artery with aneurysmal dilation. A role of this almost rare vascular condition in causing painful ophthalmoplegia is discussed.

Regulation of neuronal cell death by MST1-FOXO1 signaling

The protein kinase mammalian Sterile 20-like kinase 1 (MST1) plays a critical role in the regulation of cell death. Recent studies suggest that MST1 mediates oxidative stress-induced neuronal cell death by phosphorylating the transcription factor FOXO3 at serine 207, a site that is conserved in other FOXO family members. Here, we show that MST1-induced phosphorylation of FOXO1 at serine 212, corresponding to serine 207 in FOXO3, disrupts the association of FOXO1 with 14-3-3 proteins. Accordingly, MST1 mediates the nuclear translocation of FOXO1 in primary rat cerebellar granule neurons that are deprived of neuronal activity. We also find a requirement for MST1 in cell death of granule neurons upon withdrawal of growth factors and neuronal activity, and MST1 induces cell death in a FOXO1-dependent manner. Finally, we show that the MST1-regulatory, scaffold protein Nore1 is required for survival factor deprivation induced neuronal death. Collectively, these findings define MST1-FOXO1 signaling as an important link survival factor deprivation-induced neuronal cell death with implications for our understanding of brain development and neurological diseases.

Activation of FOXO1 by Cdk1 in cycling cells and postmitotic neurons

Activation of cyclin-dependent kinase 1 (Cdk1) has been linked to cell death of postmitotic neurons in brain development and disease. We found that Cdk1 phosphorylated the transcription factor FOXO1 at Ser249 in vitro and in vivo. The phosphorylation of FOXO1 at Ser249 disrupted FOXO1 binding with 14-3-3 proteins and thereby promoted the nuclear accumulation of FOXO1 and stimulated FOXO1-dependent transcription, leading to cell death in neurons. In proliferating cells, Cdk1 induced FOXO1 Ser249 phosphorylation at the G2/M phase of the cell cycle, resulting in FOXO1-dependent expression of the mitotic regulator Polo-like kinase (Plk). These findings define a conserved signaling link between Cdk1 and FOXO1 that may have a key role in diverse biological processes, including the degeneration of postmitotic neurons.

Different geometric patterns of pacifiers compared on the basis of finite element analysis

AIM

This study was carried out with the purpose to show on a virtual model of oral cavity the mechanical behaviour of different kinds of pacifiers with different pressure levels that can be likened to a condition of rest and deglutition.

MATERIALS AND METHODS

Three different types of dummies, orthodontic- (A), cherry- (B) and drop- (C) shaped from an anatomical point of view, were inserted between the palate and the tongue in a virtual system by means of a finite element simulation. The palatal structure was recreated through tridimensional laser scanning, while the tongue structure was reconstructed by a software suitable for reproducing solids. Also the image of the pacifiers was developed by computer-aided scanning and reproduction. Suitable constraints were inserted and high and low pressure levels were exerted on these systems. FEA simulation allowed us to distribute the strain on the palate according to the different geometrical structures of the objects.

RESULTS

Dummy A shows a more uniform and wider crosswise stress distribution with also a lesser load on the anterior palatal crest. Dummy B and C, on the contrary, show a more dot-like behaviour inducing a higher stress due to contact on restricted points.

CONCLUSION

The characteristics of dummy A, although they have not been clinically investigated yet, seem to be the fittest ones to guarantee the maintenance of the transversal diameters of the premaxilla and reduce the risk of open bite.

DNp73α protects myogenic cells from apoptosis

The P73 gene is transcribed from two promoters, P1 and P2, that direct the expression of multiple transactivation competent (TA) and dominant negative (DN) isoforms. TAp73 transcription factors mediate cell cycle arrest and/or apoptosis in response to DNA damage and are involved in developmental processes. P73 mRNA levels increase and the P1p73 promoter is upregulated during myogenic differentiation of C2C12 skeletal muscle satellite cells. The DNp73 proteins act as trans-repressors of p53- and p73-dependent transcription, and possess both antiapoptotic and pro-proliferative potential. Here, we show that DNp73alpha is expressed in proliferating C2C12 myoblasts, rapidly accumulates in differentiating myocytes and remains elevated in C2C12 myotubes. By combining transactivation assays and chromatin immunoprecipitation analysis, we could show that the upregulation of the P2p73 promoter during myogenic differentiation is mediated by the coordinated recruitment and activity of MyoD and p53/p73. Abrogation of DNp73 expression by specific siRNA led to a strong potentiation of the spontaneous apoptosis of C2C12 myoblasts induced to differentiate. Finally, unlike TAp73 that contributes to DNA damage-induced apoptosis of myotubes, endogenous DNp73 mediates the relative resistance of differentiated myotubes to DNA damage. Altogether, our findings identify DNp73alpha as an important target in designing strategies aimed at the potentiation of the regenerative potential of skeletal satellite cells.

Spontaneous intracranial hypotension: case report

Spontaneous intracranial hypotension is a well defined entity, however it is characterised by a relevant clinical heterogeneity. The main feature is orthostatic headache, often accompanied by other symptoms. The diagnosis is easily made in the presence of orthostatic headache, excluding an obvious aetiology of low cerebrospinal fluid (CSF) pressure, and often there is no evidence of direct or indirect CSF leak.

A role of p73 in mitotic exit

The p53-related p73 proteins regulate developmental processes, cell growth, and DNA damage response. p73 function is regulated by post-translational modifications and protein-protein interactions. At the G2/M transition, p73 is phosphorylated at Thr-86 by the p34cdc2/cyclin B complex; this is associated with its exclusion from condensed chromosomes and loss of DNA binding and transcriptional activation ability. Here we showed that p73 hypo-phosphorylated species reappear during mitotic exit, concomitant with p73 relocalization to telophase nuclei and recovered ability to activate transcription. Functional knock-out of p73 gene expression by small interfering RNAs (siRNAs) alters mitotic progression, yielding an increase of ana-telophase cells, the accumulation of aberrant late mitotic figures, and the appearance of abnormalities in the subsequent interphase. This p73 activity at the M-to-G1 transition is mediated by its transactivating function because expression of the transcription dominant negative mutant p73DD induces the same mitotic exit phenotype. We also found that the cyclin-dependent kinase inhibitor Kip2/p57 gene is a specific target of p73 regulation during mitotic exit and re-entry into G1. Both knock-out of p73 gene expression by siRNAs and abrogation of p73-dependent transcription by the p73DD mutant abrogate Kip2/p57 increase at the M-to-G1 transition. Moreover, similar abnormalities (e.g. delay in late mitotic stages with the accumulation of aberrant ana-telophase figures, and abnormalities in the following interphase) are observed in cultures in which the expression of Kip2/p57 is abrogated by siRNAs. These results identify a novel p73-Kip2/p57 pathway that coordinates mitotic exit and transition to G1.

Long-term idebenone treatment of vascular and degenerative brain disorders of the elderly

A multicentre study with an open experimental design was carried out on 118 patients suffering from mild to moderate cognitive decline due to cerebrovascular and degenerative disorders (chronic cerebrovascular disorders, CCVD; multi-infarct dementia, MID; aging brain, AB; dementia of Alzheimer's type, DAT). All patients, after a wash-out period of 3 weeks, were treated with idebenone (45 mg twice daily by oral route) for a period of 6 months. Behavioral and cognitive measures (Sandoz Clinical Assessment of Geriatrics, SCAG; Serial Learning Test) were applied to evaluate the long term therapeutical aspects. The results, analyzed by multivariate analysis of variance and chi2 test, showed a significant improvement of the cognitive profile in all patients, more evident in CCVD and AB groups. No remarkable side-effects were found in all groups of patients, thus confirming good tolerability of idebenone.

p73 is regulated by phosphorylation at the G2/M transition

p73 is a p53 paralog that encodes proapoptotic (transactivation-competent (TA)) and antiapoptotic (dominant negative) isoforms. TAp73 transcription factors mediate cell cycle arrest and/or apoptosis in response to DNA damage and are involved in developmental processes in the central nervous system and the immune system. p73 proteins may also play a role in the regulation of cell growth. Indeed, p73 expression is itself modulated during the cell cycle and TAp73 proteins accumulate in S phase cells. In addition, the function of p73 proteins is also regulated by post-translational modifications and protein-protein interactions in different cellular and pathophysiological contexts. Here we show that p73 is a physiological target of the p34cdc2-cyclin B mitotic kinase complex in vivo. Both p73beta and p73alpha isoforms are hyperphosphorylated in normal mitotic cells and during mitotic arrest induced by microtubule-targeting drugs. p34cdc2-cyclin B phosphorylates and associates with p73 in vivo, which results in a decreased ability of p73 to both bind DNA and activate transcription in mitotic cells. Indeed, p73 is excluded from condensed chromosomes in meta- and anaphase, redistributes throughout the mitotic cytoplasm, and unlike p53, shows no association with centrosomes. Together these results indicate that M phase-specific phosphorylation of p73 by p34cdc2-cyclin B is associated with negative regulation of its transcriptional activating function.

Physical and functional interaction between HCV core protein and the different p73 isoforms

Hepatitis C virus (HCV) core protein is a structural viral protein that packages the viral genomic RNA. In addition to this function, HCV core also modulates a number of cellular regulatory functions. In fact, HCV core protein has been found to modulate the expression of the cyclin-dependent inhibitor p21(WAF1/CIP1) and to promote both apoptosis and cell proliferation through its physical interaction with p53. Here, we studied the ability of HCV core to bind the p53-related p73 protein, its isoforms and its deletion mutants. We found that HCV core co-immunoprecipitated with p73 in HepG2 and SAOS-2 cells. Deletion mutational analysis of p73 indicates that the domain involved in HCV core binding is located between amino-acid residues 321-353. We also demonstrate that p73/core interaction results in the nuclear translocation of HCV core protein either in the presence of the p73 alpha or p73 beta tumor-suppressor proteins. In addition, the interaction with HCV core protein prevents p73 alpha, but not p73 beta dependent cell growth arrest in a p53-dependent manner. Our findings demonstrate that HCV core protein may directly influence the various p73 functions, thus playing a role in HCV pathogenesis.

DNA damage-dependent acetylation of p73 dictates the selective activation of apoptotic target genes

The tumor suppressor p53 and its close relative p73 are activated in response to DNA damage resulting in either cell cycle arrest or apoptosis. Here, we show that DNA damage induces the acetylation of p73 by the acetyltransferase p300. Inhibiting the enzymatic activity of p300 hampers apoptosis in a p53(-/-) background. Furthermore, a nonacetylatable p73 is defective in activating transcription of the proapoptotic p53AIP1 gene but retains an intact ability to regulate other targets such as p21. Finally, p300-mediated acetylation of p73 requires the protooncogene c-abl. Our results suggest that DNA damage-induced acetylation potentiates the apoptotic function of p73 by enhancing the ability of p73 to selectively activate the transcription of proapoptotic target genes.

[++Scintimammography: a new imaging technique for diagnosis and follow-up of breast cancer]

99m Tc MiBi has emerged as a new imaging technique for primary breast carcinomas. The aim of this study was to analyze the diagnostic performance and the additional information provided by scintimammography (SMN). Two hundred and forty consecutive women referred to surgery for abnormalities breast or suspicious breast cancer were scanned before surgery. Sensitivity and specificity were respectively 92% and 53%. PPV: 77.5% and PVN: 79.3%. All false negative scans occurred in cancers 1 cm. SMN detected multiple foci of uptake in the same breast in 13%, that were all confirmed to be multifocal disease and histology. Controlateral focal uptake was also detected; at this time 5/27 are confirmed to be bilateral breast neoplasms; 22 patients are in follow-up. SMN is reliable in the diagnosis of breast cancer and also with difficult cases of mammography. Moreover, SMN provides additional qualitative information in 19.6% of breast carcinomas, such as chest wall infiltration, multifocal or bilateral breast cancer.

Spinal chondroma of the lumbar tract: case report

BACKGROUND

Cartilage-forming tumors are benign cartilaginous tumors that rarely affect the spinal canal: they account for 2% of all spinal tumors and 2.6% of all benign bone tumors. Pathologically, they may be classified as chondromas, osteochondromas, chondroblastomas, and chondromyxoid fibromas. This oncotype may remain asymptomatic (it is confined within the vertebral structure) or may present as a hard paravertebral swelling (it invades the paravertebral structures) or more rarely, with a slowly-developing neurologic syndrome (it extends into the vertebral canal).

METHODS

Thirty-one cases have been reported (including our case) of benign cartilage-forming tumors localized in the lumbar column. Only three cases of chondroma of the lumbar spine presented with lumbar radicular pain. We report a fourth case and review clinical and radiologic characteristics of these lesions.

RESULTS

Eleven out of the 31 cases were diagnosed as chondromas, 17 as osteochondromas, while in three cases the histopathologic diagnosis was not reported. Seventeen cases originated from the neural arch, seven from the vertebral body, two from the spinous process, and in five cases the exact localization was not reported. This tumor is more frequent in males (21 cases out of 31), than in females (five cases); in five cases the sex was not reported. Mean duration of symptoms was 23 +/- 5.1 months (range: 1-96); chondromas have a short clinical history before diagnosis (13.8 +/- 3.4 months) compared to osteochondromas (28.6 +/- 7.6). Clinical presentation with local swelling is reported in 10 cases, in 10 cases local pain without radicular irradiation, in six cases lumbar pain with sciatica, in two cases signs and symptoms of cord compression, one case of cauda syndrome, while in four cases no clinical details are reported. Among the six cases presenting with sciatica, four were chondromas (in all cases the L4 level was involved), and one osteochondroma, while in one case the histopathologic diagnosis was not reported.

CONCLUSION

Computed tomography is important and indispensable for preoperative diagnosis, giving a precise indication of tumor extent and location and its relationship to the adjacent structures; while MRI is helpful in detecting patterns related to histologic malignancy. It is important to examine the whole tumor histologically because it is known that there may be small areas that show signs of malignancy; thus is more likely in chondromas than osteochondromas.

An assessment of hypothalamo-pituitary-adrenal axis functioning in non-depressed, early abstinent alcoholics

Chronic alcohol consumption has been shown to be associated with abnormalities in the regulation of the hypothalamo-pituitary-adrenal (HPA) axis in humans. However, conflicting data exist in the literature, with particular regard to studies performed in actively drinking or withdrawn alcoholics; in addition, the frequent presence of depressive disturbances in such patients may importantly affect the neuroendocrine findings. In this study, we investigated HPA function in 12 male alcoholics, in whom the presence of depression and other possible confounding factors was excluded, during the first and second weeks after cessation of ethanol intake. The plasma corticotropin (adrenocorticotropic hormone, ACTH) and cortisol levels in response to both a stimulation test with human corticotrophin-releasing hormone (CRH; 100 micrograms IV) and an insulin (0.15 UI/kg IV)-induced hypoglycaemia (ITT) were measured; the cortisol response to a standard overnight dexamethasone (1 mg) suppression test (DST) was also tested. While the mean baseline ACTH and cortisol levels, measured in the morning (0800-0830 h), were not different from those of controls, ACTH and cortisol responses to the CRH test were markedly reduced (area of secretion p < .01 and p < .05, compared to controls). Similarly, the patient group showed an almost absent ACTH and cortisol release following insulin infusion (area of secretion p < .01 compared to controls, in either case). In four patients, non-suppression of plasma cortisol levels was seen on the DST, but no significant difference from normal suppressors was noted as far as the clinical features were concerned. These findings suggest that impaired hypothalamic and pituitary responsiveness, unrelated to depressive disturbances, occurs in recently withdrawn chronic alcoholics. While the possible influence of the alcohol withdrawal syndrome should be taken into account, such a pattern may be due to increased activity of the HPA axis, even in the face of preserved basal adrenal secretion. Whether these findings reflect a direct effect of sustained ethanol exposure on the components of the HPA axis, or a non-specific marker of impaired adaptation in chronic alcoholics, deserves further investigation.

Symptomatic headaches

This paper is aimed to discuss some aspects of so-called symptomatic or secondary headaches with particular reference to the diagnostic criteria proposed by the IHS Classification Committee on headache disorders, cranial neuralgias and other head pain. Symptomatic headaches, in fact, represent an heterogenous group of conditions, sometimes with relevant clinical importance as warning symptoms of major intracranial pathology, sometimes benign in nature and with ill-defined clinical pictures and unclear relationship with the causative factor or event. It is therefore important to establish general principles for a more systematic approach to the problem of this group of headaches, also considering that some particular forms of secondary headaches, may be viewed as reliable "in-vivo" models for pathophysiological investigation in head pain.

[Not Available]

We report a case of oro-pharyngeal and oesophageal ulcerative disease in a AIDS patient. The patient complained of severe oral pain and dysphagia. Systemic manifestations as fever and fatigue were also present. Repeated microbiological exams were negative and therapy with either antibiotics or antiviral agents or corticosteroids or colchicine was unsuccessful. Thus, we started thalidomide: 200 mg/day X 21 days, followed by 100 mg/day X 25 days. A dramatic reduction of symptoms was observed within 15 days from the onset of treatment. The healing of ulcers was evident already one month after the start of therapy. No relevant side effects were reported. Among those patients with AIDS at low risk of side effects, thalidomide may represent a successful therapeutic presidium for severe ulcerative disease of the gastrointestinal tract.

Pramiracetam effects on scopolamine-induced amnesia in healthy volunteers

Pramiracetam has been evaluated for its potential antiamnesic properties in scopolamine-induced amnesia in healthy volunteers. Two groups of twelve males, 18-42 and 55-65 years old, respectively, were randomly assigned to oral treatment with pramiracetam (600 mg twice a day) or with placebo for 10 consecutive days. On day 11 each subject was injected intramuscularly with scopolamine hydrobromide (0.5 mg). Before scopolamine injection and then 1, 3 and 6 h after it, subjects were administered the following psychometric tests: simple and choice visual reaction times, digit symbol substitution test, Rey's 15 words test for short and long term verbal memory. Scopolamine significantly impaired episodic memory and selective attention tests in both scopolamine and placebo groups. Instead visuo-motor and incidental learning measures were unaffected. Pramiracetam, when compared to placebo, was able to partially reduce the amnesic effects induced by scopolamine both in young and old subjects.

Correlation of 99Tcm-sestamibi SPECT with coronary angiography in general hospital practice

One hundred and twenty-eight patients had a stress test with sestamibi injection and a coronarography within 2 months of the sestamibi study. Sestamibi studies were reconstructed using Hanning 0.65 and Wiener 1.0 filters; the latter improved the results significantly (P < 0.05). Significant correlations were found between sestamibi and coronarography: the sensitivity was 0.967 and the specificity was 0.711. Thus sestamibi is a very good compound, with excellent imaging quality, which is very sensitive for mild defects, even more sensitive than coronarography. Thorough studies of discrepancies show that they could be explained by reductions in coronary flow or myocardial reserve, even when the large epicardial vessels are disease free as occurs in various coronary involvements. A follow-up of positive patients with sestamibi and negative coronarography is absolutely necessary since this group of patients represents a 'risk' group. Moreover, sestamibi single photon emission computed tomographic accuracy is highly dependent on filter choice.

Kidney depth measured by using 99Tcm-DMSA. Comparison with CAT scan: review of 50 measurements

Measurement of kidney depths using computed axial tomographic (CAT) scans, considered as the gold standard, has been compared in 25 patients with depth measured using an isotopic method (99Tcm-DMSA). 99Tcm-DMSA underestimates renal depth in 78% of the cases (mean underestimation: 0.78 cm). The correlation coefficient between the two methods is 0.82. As a comparison, kidney depths calculated using Tonnesen's formula are also given and related to CAT scan results. The presence of renal morphological abnormalities in 18% of the studied kidneys allowed the authors to study their potential influence on 99TcmDMSA measurements. They do not seem to be very different from those obtained in morphologically normal kidneys. The different methods for kidney depth measurement described in the literature are briefly reviewed.

Monoamines and related metabolite levels in the cerebrospinal fluid of patients with dementia of Alzheimer type. Influence of treatment with L-deprenyl

An impairment of the monoaminergic systems has frequently been reported for Alzheimer's disease (AD) as well as an overactivity of cerebral monoamineoxidase B (MAO-B). L-deprenyl (LD), a selective and irreversible MAO-B inhibitor, has recently been proposed for the treatment of AD. The cerebrospinal fluid (CSF) levels of norepinephrine (NE), epinephrine (E), dopamine (DA), 3-methoxy-4-hydroxyphenylglycol (MHPG), 5-hydroxyindoleacetic acid (5-HIAA), and homovanillic acid (HVA) were studied in 14 patients suffering from dementia of Alzheimer type (DAT) and in 14 controls. A three-month double-blind study comparing LD with placebo was carried out, in the DAT group, and the influence of the treatment on neurotransmitter levels and cognitive performance was evaluated. The basal study revealed a significant reduction in CSF NE and HVA levels in DAT patients when compared with controls; the treatment with LD determined a significant decrease in HVA levels only and, as to neuropsychological investigation, a global amelioration of cognitive performances.

A quality control exercise of radionuclide calibrators among Belgian hospitals

On the initiative of the Belgian Association of Hospital Physicists, eleven Belgian hospitals participated in a quality control of radionuclide calibrators conducted in collaboration with the Central Bureau for Nuclear Measurements of the Commission of the European Communities. For practical reasons the nuclide 57Co was chosen. The results from 20 different radionuclide calibrators show a fair agreement with a similar comparison carried out in 1980 in the UK.

[Alcohol withdrawal syndrome. Effects of short-term treatment with dapiprazole]

A study on dapiprazole, a new psychotropic agent, in the treatment of patients during the alcohol withdrawal syndrome, is reported. On the basis of evaluations made on the severity of the physical and psychic symptoms of withdrawal, the conclusion is drawn that the new psychotropic agent, administered at gradually increasing doses of 40 to 90 mg/kg for 7 days, completely controls the clinical symptomatology at least in 70% of the cases treated.

Effect of exercise on the leg distribution of C15O2 and 15O2 in normals and in patients with peripheral ischemia: a study using positron tomography

In order to evaluate regional muscle blood flow and oxygen utilization, we study with positron emission tomography (PET) the distribution of C15O2 and 15O2 in 17 subjects: 5 normals (24 +/- 3 years) and 12 patients (63 +/- 13.5 years). C15O2 and 15O2 are inhalated with a steady-state technique. Positron tomograms are recorded in supine position at the greatest diameter of the leg. Exercise consists in simultaneous ankle flexions. In all normals, C15O2 and 15O2 are distributed homogeneously and symmetrically in both legs. At rest, they concentrate in the region of vascular pedicle. After exercise, C15O2 and 15O2 are electively distributed in the anterolateral region of the leg. In patients, this pattern of distribution is similar but asymmetrical. Moreover, the regional uptake of C15O2 and 15O2 often dissociates. In conclusion, C15O2 and 15O2 allow to study repeatedly muscle blood flow and oxygen utilization in patients with peripheral ischemia, both at rest and after exercise. The broad spectrum of pathological changes observed in this study needs further metabolic investigations.