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Biomedical subjects

Y Simon

Publications and source records attributed to Y Simon.

At least 19 recordsLinked to original sources
PubMed2003

Olfactory sensitivity for aliphatic aldehydes in squirrel monkeys and pigtail macaques.

Using a conditioning paradigm, the olfactory sensitivity of three squirrel monkeys and three pigtail macaques for a homologous series of aliphatic aldehydes ( n-butanal to n-nonanal) was assessed. With only few exceptions, the animals of both species significantly discriminated concentrations below 1 ppm from the odorless solvent, and with n-butanal and n-hexanal individual pigtail macaques even demonstrated thresholds below 1 ppb. The results showed (1). both primate species to have a well-developed olfactory sensitivity for aliphatic aldehydes, (2). pigtail macaques to generally perform better than squirrel monkeys in detecting members of this class of odorants, and (3). no significant correlation between perceptibility in terms of olfactory detection thresholds and carbon chain length of the aliphatic aldehydes in both species tested. These findings lend further support to the growing body of evidence suggesting that between-species comparisons of the number of functional olfactory receptor genes or of neuroanatomical features are poor predictors of olfactory performance. Further, our findings suggest that olfaction may play an important and hitherto underestimated role in the regulation of behavior in the species tested.

Administration, Inhalation↗
PubMed2001

Selective handling of information in patients suffering from restrictive anorexia in an emotional Stroop test and a word recognition test.

Several studies have been carried out using the Stroop test in eating disorders. Some of these studies have brought to light the existence of cognitive and attention deficits linked principally to weight and to food in anorexic and bulimic patients. The aim of the current study is to replicate and to clarify the existence of cognitive and attention deficits in anorexic patients using the Stroop test and a word recognition test. The recognition test is made up of 160 words; 80 words from the previous Stroop experiment mixed at random and matched from a semantic point of view to 80 distractions. The recognition word test is carried out 2 or 3 days after the Stroop test. Thirty-two subjects took part in the study: 16 female patients hospitalised for anorexia nervosa and 16 normal females as controls. Our results do not enable us to confirm the existence of specific cognitive deficits in anorexic patients.

Adolescent↗
PubMed1999

Bone mineral density and vertebral fractures in men.

In women, many studies indicate that the risk of vertebral fragility fractures increases as bone mineral density (BMD) declines. In contrast, few studies are available for BMD and vertebral fractures in men. It is uncertain that the strength of the relationship between BMD and fractures is similar in magnitude in middle-aged men and in postmenopausal women. In the present study, 200 men (mean age 54.7 years) with lumbar osteopenia (T-score < -1.5) were recruited to examine the relationships between spine BMD and hip BMD and the associations of BMD with vertebral fractures. Lumbar BMD was assessed from L2 to L4, in the anteroposterior view, using dual-energy X-ray densitometry. At the upper left femur, hip BMD was measured at five regions of interest: femoral neck, trochanter, intertrochanter, Ward's triangle and total hip. Spinal radiographs were analyzed independently by two trained investigators and vertebral fracture was defined as a reduction of at least 20% in the anterior, middle or posterior vertebral height. Spinal radiographs evidenced at least one vertebral crush fracture in 119 patients (59.5%). The results of logistic regression showed that age, femoral and spine BMDs were significant predictors of the presence of a vertebral fracture. Odds ratios for a decrease of 1 standard deviation ranged from 1.8 (1.3-2.8) for spine BMD to 2.3 (1.5-3.6) for total hip BMD. For multiple fractures odds ratios ranged from 1.7 (1.1-2.5) for spine BMD to 2.6 (1.7-4.3) for total hip BMD. In all models, odds ratios were higher for hip BMD than for spine BMD, particularly in younger men, under 50 years. A T-score < -2.5 in the femur (total femoral site) was associated with a 2.7-fold increase in the risk of vertebral fracture while a T-score < -2.5 in the spine was associated with only a 2-fold increase in risk. This study confirms the strong association of age and BMD with vertebral fractures in middle-aged men, shows that the femoral area is the best site of BMD measurement and suggests that a low femoral BMD could be considered as an index of severity in young men with lumbar osteopenia.

Absorptiometry, Photon↗
PubMed1997

Brain hypometabolism of glucose in bulimia nervosa.

OBJECTIVE: A cerebral function lateralization has been described in bulimic patients in positron emission tomography (PET) studies realized during a specific cognitive task. The purpose of this study was to evaluate, at rest, brain glucose metabolism in patients with bulimia nervosa. METHOD: PET with (18-F)-fluorodeoxyglucose was used to evaluate cerebral glucose metabolism in 11 normal-weight bulimic girls compared to 11 age- and sex-matched healthy volunteers. Patients were diagnosed following DSM-IV and were off psychoactive medication. RESULTS: In comparison with control subjects, bulimic patients showed global and regional absolute hypometabolism of glucose. In relative values, only parietal cortex metabolism was significantly lower in bulimic patients. No correlation was found within groups for absolute or relative cerebral glucose metabolic rates (rCMRglu) and body mass index (BMI), anxiety scores, or Hamilton scores of depression. DISCUSSION: Since previous studies have demonstrated similar disturbances in anorectic patients, we hypothesized that these observations could be a consequence of neurobiological perturbations following nutritional deficiencies or a particular cerebral dysfunction in eating disorders.

Adolescent↗
PubMed1996

Brain hypometabolism of glucose in anorexia nervosa: normalization after weight gain.

Using positron emission tomography and (18-F)-fluorodeoxyglucose, we studied cerebral glucose metabolism in 10 anorectic girls within their underweight state and after weight gain. Ten age- and sex-matched healthy volunteers were used as controls. Both groups were scanned during rest, eyes closed and with low ambient noise. In absolute values, the underweight anorectic patients, when compared to control subjects, showed a global (p = 0.002) and regional (p < or = 0.001) hypometabolism of glucose which normalized with weight gain. In relative values, no global difference could be assessed between underweight anorectic patients and controls but a trend can, nevertheless, be observed toward parietal and superior frontal cortex hypometabolism associated with a relative hypermetabolism in the caudate nuclei and in the inferior frontal cortex. After weight gain, all regions normalized for absolute and relative values, although a trend appears toward relative parietal hypometabolism and inferior frontal cortex hypermetabolism in weight gain anorectic patients. Absolute brain glucose hypometabolism might result from neuroendocrinological or morphological aspects of anorexia nervosa or might be the expression of altered neurotransmission following deficient nutritional state. As some differences exists in relative values in underweight patients and tend to persist in weight gain states, this could support a potential abnormal cerebral functioning, a different reaction to starvation within several regions of the brain or different restoration rates according to the region.

Adolescent↗
PubMed1993

Taste responsiveness in anorexia nervosa.

Preferences for sugar/fat mixtures were examined in 12 anorectic females and in 14 normal-weight volunteer controls. The subjects, recruited at an eating-disorders clinic in Paris, were tested after an overnight fast and 2 hours after lunch. Anorectic patients disliked the taste of foods rich in fat more than did controls. Perceptions and preferences for sweet taste did not differ between anorectic females and controls. After lunch, taste preference ratings were equally reduced in both groups, suggesting that satiety aversion to sucrose is present even in anorexia nervosa.

Adult↗
PubMed1993

[Diagnostic criteria in bulimia: reassessment and proposals based on a series of 539 cases].

Bulimia nervosa is a recently identified psychiatric disorder. Several clinical definitions have been successively proposed, some of which contradictory. In a multicenter study (INSERM clinical research network), 539 consecutive outpatients with bulimic behaviors were evaluated in 18 treatment centers and classified according to several diagnostic reference systems. We tested the validity of diagnostic criteria proposed by the American Psychiatric Association for DSM-IV classification. Our data support inclusion of both purging and nonpurging subtypes for the diagnosis of bulimia nervosa. The newly defined syndrome "Binge Eating Disorder" should be retained, but its diagnostic criteria modified.

Adolescent↗