Serotonergic and Dopaminergic Lesions Underlying Parkinsonian Neuropsychiatric Signs

BACKGROUND

Parkinson's disease (PD) is characterized by heterogeneous motor and nonmotor manifestations related to alterations in monoaminergic neurotransmission systems. Nevertheless, the characterization of concomitant dopaminergic and serotonergic dysfunction after different durations of Parkinson's disease, as well as their respective involvement in the expression and severity of neuropsychiatric signs, has gained little attention so far.

METHODS

To fill this gap, we conducted a cross-sectional study combining clinical and dual-tracer positron emission tomography (PET) neuroimaging approaches, using radioligands of dopamine ([¹¹ C]-N-(3-iodoprop-2E-enyl)-2-beta-carbomethoxy-3-beta-(4-methylphenyl)-nortropane) ([¹¹ C]PE2I) and serotonin ([¹¹ C]-N,N-dimethyl-2-(-2-amino-4-cyanophenylthio)-benzylamine) ([¹¹ C]DASB) reuptake, after different durations of Parkinson's disease (ie, in short-disease duration drug-naive de novo (n = 27, 0-2 years-duration), suffering from apathy (n = 14) or not (n = 13); intermediate-disease duration (n = 15, 4-7 years-duration) and long-disease duration, non-demented (n = 15, 8-10 years-duration) patients). Fifteen age-matched healthy subjects were also enrolled.

RESULTS

The main findings are threefold: (1) both dopaminergic and serotonergic lesions worsen with the duration of Parkinson's disease, spreading from midbrain/subcortical to cortical regions; (2) the presence of apathy at PD onset is associated with more severe cortical and subcortical serotonergic and dopaminergic disruption, similar to the denervation pattern observed in intermediate-disease duration patients; and (3) the severity of parkinsonian apathy, depression, and trait-anxiety appears primarily related to serotonergic alteration within corticostriatal limbic areas.

CONCLUSIONS

Altogether, these findings highlight the prominent role of serotonergic degeneration in the expression of several neuropsychiatric symptoms occurring after different durations of Parkinson's disease. © 2021 International Parkinson and Movement Disorder Society.

What do error patterns in processing facial expressions, social interaction scenes and vocal prosody tell us about the way social cognition works in children with 22q11.2DS?

Impairments in social cognition have been frequently described in 22q11.2 deletion syndrome (22q11.2DS) and are thought to be a hallmark of difficulties in social interactions. The present study addresses aspects that are critical for everyday social cognitive functioning but have received little attention so far. Sixteen children with 22q11.2DS and 22 controls completed 1 task of facial expression recognition, 1 task of attribution of facial expressions to faceless characters involved in visually presented social interactions, and 1 task of attribution of facial expressions to characters involved in aurally presented dialogues. All three tasks have in common to involve processing of emotions. All participants also completed two tasks of attention and two tasks of visual spatial perception, and their parents completed some scales regarding behavioural problems of their children. Patients performed worse than controls in all three tasks of emotion processing, and even worse in the second and third tasks. However, they performed above chance level in all three tasks, and the results were independent of IQ, age and gender. The analysis of error patterns suggests that patients tend to coarsely categorize situations as either attractive or repulsive and also that they have difficulties in differentiating emotions that are associated with threats. An isolated association between the tasks of emotion and behaviour was found, showing that the more frequently patients with 22q11.2DS perceive happiness where there is not, the less they exhibit aggressive behaviour.

Universal School-Based Intervention Does Not Reduce Socioeconomic Inequalities in Weight Status among Adolescents

Background: Differences in weight status by socioeconomic position occur during adolescence and is known as weight social gradient (WSG). The PRALIMAP (Promotion de l'ALIMentation et de l'Activité Physique) trial highlighted that a universal intervention was effective in reducing overweight and obesity prevalence among adolescents. However, its ability to reduce the WSG is unclear. This study aimed to evaluate the impact of the PRALIMAP intervention on the WSG among adolescents. Methods: Data were obtained from 3504 adolescents who participated in the school-based PRALIMAP trial between 2006 and 2009. The PRALIMAP study consisted of three interventional strategies: educational, environmental, screening and care. Weight status was assessed by body mass index (BMI) z-score and overweight and obesity prevalence. The "indice de position sociale des élèves" was used to measure adolescents' socioeconomic status. Linear regression and hierarchical models were used to assess the WSG and its evolution, respectively. Results: Among all adolescents (14-18 years old), significant WSG was identified at baseline: BMI z-score (β = -0.06; p < 0.0001), overweight and obesity prevalence (β = -2.86; p < 0.0001). Overall, the intervention conferred no significant reduction in the WSG: BMI z-score (β = -0.01 [-0.02 to 0.01], p = 0.48), overweight and obesity prevalence (β = -0.01 [-0.07 to 0.05], p = 0.73). Similar results were observed for adolescents whatever the interventional strategy they benefited from in the PRALIMAP trial. Conclusions: This study provided no evidence that the PRALIMAP universal intervention was effective in reducing the socioeconomic inequalities in weight status among adolescents. Different interventions that account for social differences should be considered to tackle these inequalities.

Wait and you shall see: sexual delay discounting in hypersexual Parkinson's disease

Patients with Parkinson's disease may develop impulse control disorders under dopaminergic treatments. Impulse control disorders include a wide spectrum of behaviours, such as hypersexuality, pathological gambling or compulsive shopping. Yet, the neural systems engaged in specific impulse control disorders remain poorly characterized. Here, using model-based functional MRI, we aimed to determine the brain systems involved during delay-discounting of erotic rewards in hypersexual patients with Parkinson's disease (PD+HS), patients with Parkinson's disease without hypersexuality (PD - HS) and controls. Patients with Parkinson's disease were evaluated ON and OFF levodopa (counterbalanced). Participants had to decide between two options: (i) wait for 1.5 s to briefly view an erotic image; or (ii) wait longer to see the erotic image for a longer period of time. At the time of decision-making, we investigated which brain regions were engaged with the subjective valuation of the delayed erotic reward. At the time of the rewarded outcome, we searched for the brain regions responding more robustly after waiting longer to view the erotic image. PD+HS patients showed reduced discounting of erotic delayed rewards, compared to both patients with Parkinson's disease and controls, suggesting that they accepted waiting longer to view erotic images for a longer period of time. Thus, when using erotic stimuli that motivate PD+HS, these patients were less impulsive for the immediate reward. At the brain system level, this effect was paralleled by the fact that PD+HS, as compared to controls and PD - HS, showed a negative correlation between subjective value of the delayed reward and activity of medial prefrontal cortex and ventral striatum. Consistent with the incentive salience hypothesis combining learned cue-reward associations with current relevant physiological state, dopaminergic treatment in PD+HS boosted excessive 'wanting' of rewards and heightened activity in the anterior medial prefrontal cortex and the posterior cingulate cortex, as reflected by higher correlation with subjective value of the option associated to the delayed reward when ON medication as compared to the OFF medication state. At the time of outcome, the anterior medial prefrontal/rostral anterior cingulate cortex showed an interaction between group (PD+HS versus PD - HS) and medication (ON versus OFF), suggesting that dopaminergic treatment boosted activity of this brain region in PD+HS when viewing erotic images after waiting for longer periods of time. Our findings point to reduced delay discounting of erotic rewards in PD+HS, both at the behavioural and brain system levels, and abnormal reinforcing effect of levodopa when PD+HS patients are confronted with erotic stimuli.10.1093/brain/awy298_video1awy298media15983845074001.

Exploratory case study of monozygotic twins with 22q11.2DS provides further clues to circumscribe neurocognitive markers of psychotic symptoms

Variation in facial emotion processing abilities may contribute to variability in penetrance for psychotic symptoms in 22q11.2DS. However, the precise nature of the social cognitive dysfunction (i.e., facial expression perception vs. emotion recognition), the potential additional roles of genetic and environmental variabilities, and consequently the possibility of using this neurocognitive marker in clinical monitoring remain unclear. The present case study aimed at testing the hypothesis that when confounding factors are controlled, the presence of psychotic symptoms in 22q11.2DS is associated, at the individual level, with a neural marker of facial expression perception rather than explicit emotional face recognition. Two monozygotic twins with 22q11.2DS discordant for psychiatric manifestations performed (1) a classical facial emotion labelling task and (2) an implicit neural measurement of facial expression perception using a frequency-tagging approach in electroencephalography (EEG). Analysis of the periodic brain response elicited by a change of facial expression from neutrality indicated that the twin with psychotic symptoms did not detect emotion among neutral faces while the twin without the symptoms did. In contrast, both encountered difficulties labelling facial emotion. The results from this exploratory twin study support the idea that impaired facial expression perception rather than explicit recognition of the emotion expressed might be a neurocognitive endophenotype of psychotic symptoms that could be reliable at a clinical level. Although confirmatory studies should be required, it facilitates further discussion on the etiology of the clinical phenotype in 22q11.2DS.

12q13.12q13.13 microdeletion encompassing ACVRL1 and SCN8A genes: Clinical report of a new contiguous gene syndrome

Hereditary hemorrhagic telangiectasia is usually linked to the presence of a pathogenic mutation ACVRL1 or ENG. Thus, apparently there is no benefit to perform an array CGH in case of HHT. However, ENG has been involved in a contiguous gene syndrome due to a de novo 9q33.3q34.11 microdeletion. We describe here a new contiguous gene syndrome involving ACVRL1 gene. A 50-year-old female patient had a typical clinical presentation of hereditary hemorrhagic telangiectasia (HHT) with epistaxis, cutaneous-mucous telangiectases, arteriovenous malformation. She also presented a cognitive disability. Cognitive assessment showed a heterogeneous cognitive disorder predominating in the executive sphere without intellectual deficiency. She had no peculiar morphological feature. Neurological examination disclosed the presence of contralateral mirror movements during voluntary movement of each hand. A heterozygous deletion of the whole ACVRL1 gene (exons 1 to 10) was found to be responsible for the HHT features. To investigate further the dysexecutive syndrome and the mirror movements, we performed oligonucleotide array comparative genomic hybridization (array CGH) study (180K, Agilent, Santa-Clara, CA, USA). This study revealed a de novo 1.58 Mb deletion on chromosome 12q13.12q13.13 encompassing the ACVRL1 and SCN8A genes. To our knowledge, this deletion has not been previously reported and defines a new contiguous gene syndrome. The loss of one ACVRL1 allele is likely to be responsible for the HHT phenotype, while the deletion of the SCN8A gene is likely to be the cause of the mild cognitive disorder. SCN8A haploinsufficiency might also be involved in the occurrence of mirror movements. This report highlights the benefit of searching for large rearrangements in cases including unusual symptoms in association with HHT. On the other hand, an early diagnosis of 12q13.12q13.13 microdeletion based on the presence of a dysexecutive syndrome and/or mirror movement may allow to prevent HHT complications.

Computer-based cognitive remediation program for the treatment of behavioral problems in children with intellectual disability: the «COGNITUS & MOI» study protocol for a randomized controlled trial

BACKGROUND

Comorbid psychiatric disorders are frequent in children with intellectual disability (ID). Given the limitations of drugs treatments, cognitive remediation could be a promising tool to reduce these challenging behaviors but evidence is still scarce. Our group recently developed the «COGNITUS & MOI» program that is designed to train the attentional and visuospatial skills in children with ID. This study investigates the efficiency of the «COGNITUS & MOI» program in this condition.

METHODS

Children (age: 6.00-13.11) with mild to moderate ID and behavioral problems, will benefit from a therapy during a 16 week randomized controlled trial. One group will be randomly treated with the «COGNITUS & MOI» program and the other with a motor skill and video viewing intervention. All participants will undergo a behavioral, functional and neurocognitive assessment at baseline, post-intervention, and 6-month follow-up. Primary outcome will be the change from the baseline of the score on the "hyperactivity - noncompliance" subscale of the Aberrant Behavior Checklist.

DISCUSSION

If the results are conclusive, the «COGNITUS & MOI» program could be added to the therapeutic arsenal against challenging behavior in children with ID.

TRIAL REGISTRATION

ClinicalTrials NCT02797418 . Date registered: 8th of June 2016.

Overview of Social Cognitive Dysfunctions in Rare Developmental Syndromes With Psychiatric Phenotype

Rare neurodevelopmental syndromes often present social cognitive deficits that may underlie difficulties in social interactions and increase the risk of psychosis or autism spectrum disorders. However, little is known regarding the specificities of social cognitive impairment across syndromes while it remains a major challenge for the care. Our review provides an overview of social cognitive dysfunctions in rare diseases associated with psychiatric symptoms (with a prevalence estimated between 1 in 1,200 and 1 in 25,000 live births: 22q11.2 deletion syndrome, Angelman syndrome, Fragile X syndrome, Klinefelter syndrome, Prader-Willi syndrome, Rett syndrome, Smith-Magenis syndrome, Turner syndrome, and Williams syndrome) and shed some light on the specific mechanisms that may underlie these skills in each clinical presentation. We first detail the different processes included in the generic expression "social cognition" before summarizing the genotype, psychiatric phenotype, and non-social cognitive profile in each syndrome. Then, we offer a systematic review of the social cognitive abilities and the disturbed mechanisms they are likely associated with. We followed the PRISMA process, including the definition of the relevant search terms, the selection of studies based on clear inclusion, and exclusion criteria and the quality appraisal of papers. We finally provide insights that may have considerable influence on the development of adapted therapeutic interventions such as social cognitive training (SCT) therapies specifically designed to target the psychiatric phenotype. The results of this review suggest that social cognition impairments share some similarities across syndromes. We propose that social cognitive impairments are strongly involved in behavioral symptoms regardless of the overall cognitive level measured by intelligence quotient. Better understanding the mechanisms underlying impaired social cognition may lead to adapt therapeutic interventions. The studies targeting social cognition processes offer new thoughts about the development of specific cognitive training programs, as they highlight the importance of connecting neurocognitive and SCT techniques.

Dietary practices in propionic acidemia: A European survey

Background

The definitive dietary management of propionic acidaemia (PA) is unknown although natural protein restriction with adequate energy provision is of key importance.

Aim

To describe European dietary practices in the management of patients with PA prior to the publication of the European PA guidelines.

Methods

This was a cross-sectional survey consisting of 27 questions about the dietary practices in PA patients circulated to European IMD dietitians and health professionals in 2014.

Results

Information on protein restricted diets of 186 PA patients from 47 centres, representing 14 European countries was collected. Total protein intake [PA precursor-free L-amino acid supplements (PFAA) and natural protein] met WHO/FAO/UNU (2007) safe protein requirements for age in 36 centres (77%). PFAA were used to supplement natural protein intake in 81% (n = 38) of centres, providing a median of 44% (14–83%) of total protein requirement. Seventy-four per cent of patients were prescribed natural protein intakes below WHO/FAO/UNU (2007) safe levels in one or more of the following age groups: 0–6 m, 7–12 m, 1–10 y, 11–16 y and > 16 y. Sixty-three per cent (n = 117) of patients were tube fed (74% gastrostomy), but only 22% received nocturnal feeds.

Conclusions

There was high use of PFAA with intakes of natural protein commonly below WHO/FAO/UNU (2007) safe levels. Optimal dietary management can only be determined by longitudinal, multi-centre, prospective case controlled studies. The metabolic instability of PA and small patient cohorts in each centre ensure that this is a challenging undertaking.

Social cognition in Wilson's disease: A new phenotype?

Studies focusing on neuropsychological impairments in Wilson’s disease (WD) have highlighted that patients showing neurological signs present significant deficits in a wide range of cognitive domains. Attentional and executive impairments have also been described in people with hepatic WD. However, social cognition abilities, i.e. cognitive processes required to perceive the emotions, intentions and dispositions of other people, have not been clearly investigated in WD. In this study we examined the social cognitive functioning in 19 patients with WD depending on their clinical status–Neurological versus Non-Neurological (“hepatic”) forms–compared to 20 healthy controls. For the very first time, results highlighted that patients with WD had significant impairments in the three major components of social cognition: emotion recognition, Theory of Mind and attributional style. However, these deficits differ depending on the form of the disease: patients with neurological signs showed a wide range of deficits in the three components that were assessed–results notably revealed impairments in recognizing “fear”, “anger”, and “disgust”, a significant Theory of Mind deficit and an “aggression bias”–whereas Non-Neurological patients only showed deficits on test assessing attributional bias, with a trend to react more “aggressively” to ambiguous social situations than healthy controls, as observed in Neurological WD patients, and a specific impairment in “anger” recognition. Our findings are discussed in the light of both neurocognitive impairments and brain damages, and especially those affecting the basal ganglia, as observed in people with WD.

Dietary practices in isovaleric acidemia: A European survey

Background

In Europe, dietary management of isovaleric acidemia (IVA) may vary widely. There is limited collective information about dietetic management.

Aim

To describe European practice regarding the dietary management of IVA, prior to the availability of the E-IMD IVA guidelines (E-IMD 2014).

Methods

A cross-sectional questionnaire was sent to all European dietitians who were either members of the Society for the Study of Inborn Errors of Metabolism Dietitians Group (SSIEM-DG) or whom had responded to previous questionnaires on dietetic practice (n = 53). The questionnaire comprised 27 questions about the dietary management of IVA.

Results

Information on 140 patients with IVA from 39 centres was reported. 133 patients (38 centres) were given a protein restricted diet. Leucine-free amino acid supplements (LFAA) were routinely used to supplement protein intake in 58% of centres. The median total protein intake prescribed achieved the WHO/FAO/UNU [2007] safe levels of protein intake in all age groups. Centres that prescribed LFAA had lower natural protein intakes in most age groups except 1 to 10 y. In contrast, when centres were not using LFAA, the median natural protein intake met WHO/FAO/UNU [2007] safe levels of protein intake in all age groups. Enteral tube feeding was rarely prescribed.

Conclusions

This survey demonstrates wide differences in dietary practice in the management of IVA across European centres. It provides unique dietary data collectively representing European practices in IVA which can be used as a foundation to compare dietary management changes as a consequence of the first E-IMD IVA guidelines availability.

Dietary management of urea cycle disorders: European practice

BACKGROUND

There is no published data comparing dietary management of urea cycle disorders (UCD) in different countries.

METHODS

Cross-sectional data from 41 European Inherited Metabolic Disorder (IMD) centres (17 UK, 6 France, 5 Germany, 4 Belgium, 4 Portugal, 2 Netherlands, 1 Denmark, 1 Italy, 1 Sweden) was collected by questionnaire describing management of patients with UCD on prescribed protein restricted diets.

RESULTS

Data for 464 patients: N-acetylglutamate synthase (NAGS) deficiency, n=10; carbamoyl phosphate synthetase (CPS1) deficiency, n=29; ornithine transcarbamoylase (OTC) deficiency, n=214; citrullinaemia, n=108; argininosuccinic aciduria (ASA), n=80; arginase deficiency, n=23 was reported. The majority of patients (70%; n=327) were aged 0-16y and 30% (n=137) >16y. Prescribed median protein intake/kg body weight decreased with age with little variation between disorders. The UK tended to give more total protein than other European countries particularly in infancy. Supplements of essential amino acids (EAA) were prescribed for 38% [n=174] of the patients overall, but were given more commonly in arginase deficiency (74%), CPS (48%) and citrullinaemia (46%). Patients in Germany (64%), Portugal (67%) and Sweden (100%) were the most frequent users of EAA. Only 18% [n=84] of patients were prescribed tube feeds, most commonly for CPS (41%); and 21% [n=97] were prescribed oral energy supplements.

CONCLUSIONS

Dietary treatment for UCD varies significantly between different conditions, and between and within European IMD centres. Further studies examining the outcome of treatment compared with the type of dietary therapy and nutritional support received are required.

Deep brain stimulation of the subthalamic nucleus, but not dopaminergic medication, improves proactive inhibitory control of movement initiation in Parkinson's disease

Slowness in movement initiation is a cardinal feature of Parkinson's disease (PD) that is still poorly understood and unsuccessfully alleviated by standard therapies. Here, we raise this major clinical issue within the framework of a novel theoretical model that allows a better understanding of the basic mechanisms involved in movement initiation. This model assumes that movement triggering is inhibited by default to prevent automatic responses to unpredictable events. We investigated to which extent the top-down control necessary to release this locking state before initiating actions is impaired in PD and restored by standard therapies. We used a cue-target reaction time task to test both the ability to initiate fast responses to targets and the ability to refrain from reacting to cues. Fourteen patients with dopaminergic (DA) medication and 11 with subthalamic nucleus (STN) stimulation were tested on and off treatment, and compared with 14 healthy controls. We found evidence that patients withdrawn from treatment have trouble voluntarily releasing proactive inhibitory control; while DA medication broadly reduces movement initiation latency, it does not reinstate a normal pattern of movement initiation; and stimulation of the STN specifically re-establishes the efficiency of the top-down control of proactive inhibition. These results suggest that movement initiation disorders that resist DA medication are due to executive, not motor, dysfunctions. This conclusion is discussed with regard to the role the STN may play as an interface between non-DA executive and DA motor systems in cortico-basal ganglia loops.

How emotional pictures influence visuospatial binding in short-term memory in ageing and Alzheimer's disease?

The present study examines the prediction that emotion can facilitate short-term memory. Nevertheless, emotion also recruits attention to process information, thereby disrupting short-term memory when tasks involve high attentional resources. In this way, we aimed to determine whether there is a differential influence of emotional information on short-term memory in ageing and Alzheimer's disease (AD). Fourteen patients with mild AD, 14 healthy older participants (NC), and 14 younger adults (YA) performed two tasks. In the first task, involving visual short-term memory, participants were asked to remember a picture among four different pictures (negative or neutral) following a brief delay. The second task, a binding memory task, required the recognition by participants of a picture according to its spatial location. The attentional cost involved was higher than for the first task. The pattern of results showed that visual memory performance was better for negative stimuli than for neutral ones, irrespective of the group. In contrast, binding memory performance was essentially poorer for the location of negative pictures in the NC group, and for the location of both negative and neutral stimuli in the AD group, in comparison to the YA group. Taken together, these results show that emotion has beneficial effects on visual short-term memory in ageing and AD. In contrast, emotion does not improve their performances in the binding condition.

Fat intakes of children with PKU on low phenylalanine diets

BACKGROUND

As part of a study on the effects of a fat-supplemented phenylalanine (phe)-free protein substitute on the fatty acid status of children with phenylketonuria (PKU), the adequacy of the diets of children aged 1-10 years for fat and essential fatty acids (EFA) was assessed.

METHODS

Subjects randomized in a 1 : 1 ratio to a phe-free protein substitute supplemented with EFA (test-treatment group) or a phe-free, fat-free protein substitute (control group) for 20 weeks. 3-day semi-weighed records of food intakes collected at the end of the study period.

RESULTS

Total fat and alpha-linolenic acid (alpha-LA) intakes were found to be poor in the control group (n = 19). Those in the test-treatment group (n = 24) had higher fat and EFA intakes (P < 0.05), bringing intakes closer to population norms. The youngest children (<5 years of age) in the control group appeared to be especially vulnerable to poor fat intakes because of the restricted diversity of their diets and, regardless of age, alpha-LA intakes by this group were poor compared with the non-PKU population.

CONCLUSIONS

The quantity and quality of fat in the diets of children with PKU, in particular young children, should be given careful consideration in trying to optimize the ratio of linoleic acid: alpha-LA in their diets and in satisfying the requirements of this group for fat and alpha-LA.

Physical alginate hydrogels based on hydrophobic or dual hydrophobic/ionic interactions: Bead formation, structure, and stability

Hydrophobically associating alginate (AA) derivatives were prepared by covalent fixation of dodecyl or octadecyl chains onto the polysaccharide backbone (AA-C12/AA-C18). In semidilute solution, intermolecular hydrophobic interactions result in the formation of physical hydrogels, the physicochemical properties of which can be controlled through polymer concentration, hydrophobic chain content, and nonchaotropic salts such as sodium chloride. The mechanical properties of these hydrogels can then be reinforced by the addition of calcium chloride. The combination of both calcium bridges and intermolecular hydrophobic interactions leads to a decrease in the swelling ratio accompanied by an increase of elastic and viscous moduli. Beads made of hydrophobically modified alginate were obtained by dropping an aqueous solution of alginate derivative into a NaCl/CaCl2 solution. As compared to unmodified alginate beads, modified alginate particles proved to be stable in the presence of nongelling cations or calcium-sequestering agents. However, evidence is presented for a more heterogeneous structure than that of plain calcium alginate hydrogels with, in particular, an increase in the effective gel mesh size, as determined by partition and diffusion coefficient measurements.

Description of multicomponent adsorption and absorption phenomena from a single viewpoint

On the basis of phenomenological thermodynamics, an equation has been derived that represents one of the interphase equilibrium equations and provides a description of both multicomponent adsorption and absorption phenomena from a single point of view. The approach is based on a free-volume state equation for the adsorbed phase. It is shown that the well-known Henry, Langmuir, Fowler-Guggenheim, Temkin, and BET adsorption equations (generalized for gas mixtures) follow directly from the equation proposed with constants having a clear physical meaning.

Plasma cholesterol and endogenous cholesterol synthesis during refeeding in anorexia nervosa

Normal or high levels of cholesterol have been measured in patients with anorexia nervosa (AN). Given that cholesterol intake in AN is usually very low, the reasons for this anomaly are not clearly understood. We studied lipid and lipoprotein profiles and endogenous cholesterol synthesis, estimated by serum lathosterol, in a population of 14 girls with AN, before and during a period of 30 days refeeding. The initial body mass index (BMI) of the patients was 13.41+/-1.62 kg/m(2). No changes were observed during refeeding in endocrine parameters (ACTH, cortisol and estradiol). At Day 0 the lipids data measured here showed normal levels of triglycerides, and total cholesterol at the upper limits of the normal range (5.44+/-1 mmol/l). At this time, total and LDL cholesterol were negatively correlated with transthyretin and BMI. Serum lathosterol (a precursor in cholesterol synthesis pathway) increased significantly (5.99+/-1.75 (Day 0) vs. 8.39+/-2.96 (Day 30); P=0.02) while there was a significant decrease in apo B (0.79+/-0.33 (Day 0) vs. 0. 60+/-0.17 g/l (Day 30), P=0.02) with refeeding. Thus, patients with initial high cholesterol levels have the worst nutritional status and high cholesterol levels are not related to a de novo synthesis. This profile returns to normal with refeeding. An increase of cellular cholesterol uptake may be responsible for this apparently paradoxical evolution with increase of cholesterol synthesis and decrease of apo B during renutrition.

[Halitosis in 1999]

Bad breath is a major concern to the general population and a source of an important profit industry world wide. Between 50 and 60 per cent of the population suffer from chronic halitosis. This can have consequences for private or professional life. Reasons can imply many specialities: ENT, gastro-enterology, pneumology, hepatology, genetics and psychiatry (a high percentage of the patients who come to the clinic with a primary complaint of halitosis do not have a detectable problem). Nevertheless, 85% are stomatological and are explained by the release of volatile sulfur compounds. These substances have a very offensive odor in very low concentrations. A specialized device called a halimeter is available to measure the volatile sulphur compounds in mouth air but in practice the objective assessment of malodor is still best performed by the organoleptic method. A careful examination can determine the patient's problem in most cases. Initial treatment strategy should focus on the exact cause and on oral hygiene. In addition to the usual recommendations, the daily use of tongue cleaners is very beneficial. Other than etiologic therapy, masking can be achieved by oral care products (mouth rinses, toothpastes, chewing gums) which contain metal ions, especially zinc, that inhibit odor formation because of its affinity to sulphur compounds.

[Osteosynthesis of subcondylar fractures using compression screws with the Eckelt technic. Experiences and difficulties with the technic over 5 years]

With creation of new fixation material, the surgical treatment of displaced subcondylar fractures is most frequently used in adults. The Eckelt compression osteosynthesis is described as an easy procedure in the current literature, but, in our experience, several problems require our attention. We report the treatment of 57 patients with displaced subcondylar fractures where compression osteosynthesis was indicated. The difficulty of this technique is presented on the basis of a 5-years experience.

[Parietal grafts in maxillofacial and pre-implant surgery]

Due to the recent regulations generated by the diversity of infectious risks, autologous bone is the standard graft material in maxillofacial surgery. Although synthetic biomaterials can be useful, they remain insufficient in many situations. Among the many sites offering graft material, monocortical parietal bone which is accessible within the craniocephalic operative field has distinguishing characteristics due to its membranous embryological origin and its mode of direct ossification which does not include a cartilaginous stage. The proportion of cancellous bone per unit volume is much higher than in enchondral bone (iliac bone, ribs...). These factors are undoubtedly the source of its main qualities--very little resorption and excellent capacity for bony integration--motivating its increasingly widespread use over the past twenty years. We present our experience in a series of patients who underwent surgery between 1992 and 1997. Parietal bone was used for orthognathic, pre-implant or reconstruction surgery after trauma or carcinological trauma. We present a description of the surgical procedures together with morbidity results and compare our findings with those found in large series in the literature, particularly concerning rare neuromeningeal complications. We discuss indications for parietal grafts and their course at the receiver site.

[Gunshot wounds and injuries of the face in civilian practice]

Firearm wounds are relatively frequent in civilian practice. Due to the variable power of the weapons involved, a wide range of maxillofacial lesions are encountered and classification is a difficult task. In order to predict the gravity of the lesions, we have drawn a classification scheme from our experience with maxillofacial injuries. The scheme was based on the kind of ammunition which gives a better classification than the type of weapon. Three main categories have been identified.

[Streptomyces somaliensis mycetoma with craniofacial involvement]

Mycetoma is a chronic granulomatous infection of the skin from which grains of the causative organism are eliminated via the sinus tracts. We report a rare case of cephalic mycetoma, which presented with an extensive involvement of the skull vault, base and an extradural granuloma. The diagnosis and treatment of the disease are discussed.