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Biomedical subjects

O Bonne

Publications and source records attributed to O Bonne.

At least 19 recordsLinked to original sources
PubMed2001

Cerebral activation associated with sexual arousal in response to a pornographic clip: A 15O-H2O PET study in heterosexual men.

This study attempted to use PET and 15O-H2O to measure changes in regional cerebral blood flow (rCBF) during sexual arousal evoked in 10 young heterosexual males while they watched a pornographic video clip, featuring heterosexual intercourse. This condition was compared with other mental setups evoked by noisy, nature, and talkshow audiovisual clips. Immediately after each clip, the participants answered three questions pertaining to what extent they thought about sex, felt aroused, and sensed an erection. They scored their answers using a 1 to 10 scale. SPM was used for data analysis. Sexual arousal was mainly associated with activation of bilateral, predominantly right, inferoposterior extrastriate cortices, of the right inferolateral prefrontal cortex and of the midbrain. The significance of those findings is discussed in the light of current theories concerning selective attention, "mind reading" and mirroring, reinforcement of pleasurable stimuli, and penile erection.

Adult↗
PubMed2001

Separation-induced body weight loss, impairment in alternation behavior, and autonomic tone: effects of tyrosine.

We have investigated the effects of tyrosine on alternation behavior and hippocampal adrenergic and cholinergic tone in a model of self-induced weight loss caused by separation stress. Separation decreased body weight in mice (P < .001) and spontaneous alternations in the T-maze (P < .001). This impairment was associated with depletion of both norepinephrine (NE, P < .001) and dopamine (P < .01) while increasing MHPG (P < .05) and the ratio of MHPG/NE (P < .05). Increasing tyrosine availability restored performance to control levels (P < .001) and repleted dopamine (P < .05) and presumably also NE (indicated by increases in both MHPG, P < .001, and MHPG/NE, P < .05). Stress increased adrenergic alpha(2)-receptor density (P < .001) without changing its K(d) and the B(max) and K(d) of beta-receptors, suggesting that it decreased NE transmission through action on alpha(2)-receptors. The balance between beta- and alpha(2)-receptors appeared to be related to alternation behavior as shown by the decrease (P < .01) and increase (P < .05) in their ratios induced by stress and tyrosine, respectively. With regard to cholinergic tone, separation stress increased M1 receptor density (P < .05) and its mRNA signal (P < .001). Tyrosine further increased M1 receptor density of stressed mice (P < .05). Tyrosine might be a potential therapy for cognitive and mood problems associated with the maintenance of a reduced body weight in the treatment of obesity and in the extreme case of anorexia nervosa.

Animals↗
PubMed2001

Diet restriction in mice causes a decrease in hippocampal choline uptake and muscarinic receptors that is restored by administration of tyrosine: interaction between cholinergic and adrenergic receptors influencing cognitive function.

We have studied the effects of diet restriction (DR) to 60% and 40% of daily requirements, and tyrosine administration on cognitive function in mice, to define the nutritional-neurochemical interactions on autonomic tone involved in behavior and energy regulation. Cognitive function in the Morris Water maze was significantly impaired after 40% DR compared to both control and 60% DR. It was restored after tyrosine in association with increased M1 cholinergic and beta-adrenergic receptor function, and decreased alpha-adrenergic function. DR to 40% significantly decreased choline uptake (p <.05) and M1 receptor number (Bmax) (p <.05), without changes in affinity (Kd), choline acetyl transferase (ChAT) or acetyl cholinesterase (AChE) activity. Tyrosine administration significantly increased choline uptake (Bmax) (p <.05) and M1 density in the 40% DR (p <.01) without changes in affinity. ChAT activity was decreased after tyrosine--significantly after 40% DR (p <.05) while AChE was not affected. Both M1 mRNA and protein were not influenced by DR or tyrosine administration. Tyrosine hydroxylase mRNA was decreased significantly by 40% DR (p <.01). The effect of DR and tyrosine appeared to be both pre- and post-synaptic, indicating modulation of cholinergic activity by adrenergic tone. Nutritional effect on behavior and autonomic tone may have implications for the treatment of mood changes associated with weight loss and semi-starvation.

Animals↗
PubMed2001

Longitudinal MRI study of hippocampal volume in trauma survivors with PTSD.

OBJECTIVE: The authors prospectively explored whether a reduction in the volume of the hippocampus occurs in recent trauma survivors who develop posttraumatic stress disorder (PTSD). METHOD: Thirty-seven survivors of traumatic events were assessed within a week of the traumatic event and 6 months later. The assessment included magnetic resonance imaging of the brain (including 124 coronal slices of 1.5-mm thickness), psychometric testing, and structured clinical interviews. The Clinician-Administered PTSD Scale conferred PTSD diagnoses at 6 months. RESULTS: Ten subjects (27%) had PTSD at 6 months. The subjects with PTSD did not differ from those without PTSD in hippocampal volume (right or left) at 1 week or 6 months. There was no reduction in hippocampal volume in the PTSD subjects between 1 week and 6 months. CONCLUSIONS: Smaller hippocampal volume is not a necessary risk factor for developing PTSD and does not occur within 6 months of expressing the disorder. This brain abnormality might occur in individuals with chronic or complicated PTSD.

Adult↗
PubMed1999

Clinical doses of fluoxetine and cerebral blood flow in healthy volunteers.

RATIONALE: Of the specific serotonin reuptake inhibitors (SSRIs), fluoxetine is perhaps the most widely used. Anecdotal reports, mostly in the non-medical press, have suggested that it may positively affect psychological functioning and enhance quality of life in the absence of overt psychiatric disorder. Such wide-spread use in not supported by scientific data. OBJECTIVE: This prospective single blind study examined the effects of long term administration of clinical doses of fluoxetine on cerebral blood flow (CBF) in healthy volunteers. METHODS: Fifteen healthy subjects were examined by Tc99m HMPAO SPECT after 2 weeks of placebo administration and then after 6 weeks of fluoxetine, administered at 20 mg per day. Blood for fluoxetine and norfluoxetine plasma levels was drawn to ensure compliance. Tc99m HMPAO uptake was analyzed by the region of interest approach, normalized to the cerebellum, and by statistical parametric mapping (SPM). RESULTS: No statistically significant differences between the two conditions were detected by both techniques. Correlation analysis between fluoxetine and norfluoxetine plasma levels and rCBF yielded no statistically significant values. CONCLUSION: Our findings suggest a differential effect of fluoxetine on CBF under the following conditions: (i) mental health versus psychiatric illness; (ii) acute versus long term administration. Our findings further emphasize the importance of longitudinal studies in elucidating the physiology of the normal brain as well as the pathophysiology of psychiatric disorders.

Adult↗
PubMed1999

Childhood imaginary companionship and mental health in adolescence.

An imaginary companion (IC) is a frequently encountered childhood fantasy, invisible to anyone but the child, who may be named, addressed or played with. Whether the presence of an IC is a normal developmental feature has not been determined. We examined psychometric measures and the presence/absence of childhood IC in a sample of 850 mentally healthy adolescents. 17.6% of our subjects, more often females, reported having had such a companion. Subjects who reported having had an IC in childhood exhibited higher levels of distress and emotional discontrol, displayed prolonged transitional object attachment and immature modes of coping with stress. Thus, although childhood imaginary companionship is not indicative of psychopathology, it may denote a vulnerability for adolescent perturbation and difficulty in coping with emotionally laden situations.

Adaptation, Psychological↗
PubMed1998

Alprazolam reduces response to loud tones in panic disorder but not in posttraumatic stress disorder.

BACKGROUND: Posttraumatic stress disorder (PTSD) and panic disorder (PD) share several clinical features, and theory postulates that phasic arousal is similarly dysregulated in both. The modulation of phasic arousal can be probed by measuring the effect of pharmacologic agents on auditory startle. METHODS: Eyeblink electromyogram, heart rate, and skin conductance (SC) responses to 15 consecutive presentations of 1000-Hz, 95-dB, zero rise-time pure tones were measured, before and during treatment with alprazolam, in 9 PTSD and 9 PD patients. Concurrent anxiety was assessed by the Hamilton Anxiety Rating Scale. RESULTS: The groups did not differ in initial psychometric and physiological measures. Significant decrease in anxiety was observed in both groups during treatment. A decrease in response probability and a decrease in the SC responses were observed in PD, but not in PTSD. CONCLUSIONS: The results may reflect a difference in the modulation of phasic arousal between the disorders. They may also express an impaired between-session habituation or contextual sensitization in PTSD.

Acoustic Stimulation↗
PubMed1998

Age-related changes in brain perfusion of normal subjects detected by 99mTc-HMPAO SPECT.

Previous functional imaging data generally show impairment in global cerebral blood flow (CBF) with age. Conflicting data, however, concerning age-related changes in regional CBF (rCBF) have been reported. We examined the relative rCBF in a sample of healthy subjects of various ages, to define and localize any age-related CBF reduction. Twenty-seven healthy subjects (17 male, 10 female; mean age 49 +/- 15, range 26-71, median 47 years) were studied by 99mTc-HMPAO brain SPECT. The younger age group consisted of subjects below, the older group above 47 years of age, respectively. Analysis was performed by applying three preformed templates, each containing delineated regions of interest (ROIs), to three transaxial brain slices at approximately 4, 6, and 7 cm above the orbitomeatal line (OML). The average number of counts for each ROI was normalized to mean uptake of the cerebellum and of the whole brain slice. Globally, 99mTc-HMPAO uptake ratio normalized to cerebellum was significantly decreased in older subjects, affecting both hemispheres. A slight left-to-right asymmetry was observed in HMPAO uptake of the whole study group. It did not, however, change with age. Regionally, both cortical and subcortical structures of older subjects were involved: uptake ratio to cerebellum was significantly lower (after correction for multiple testing) in the left basal ganglia and in the left superior temporal, right frontal and bilateral occipital cortices at 4 cm above the OML. At 6 cm above the OML, reduced uptake ratios were identified in the left frontal and bilateral parietal areas. At 7 cm, reduced uptake was detected in the right frontal and left occipital cortices. Most of these differences were reduced when uptake was normalized to whole slice, whereas an increase in uptake ratios was observed in the cingulate cortex of the elderly. An inverse correlation between age and HMPAO uptake ratios normalized to cerebellum was observed in a number of brain regions. These findings suggest that advancing age has a differential effect on cerebral perfusion reflected in brain 99mTc-HMPAO uptake.

Aging↗
PubMed1997

Auditory startle responses in help-seeking trauma survivors.

Studies of the acoustic startle reflex in post-traumatic stress disorder (PTSD) yielded controversial results, whilst PTSD patients consistently report exaggerated startle. Addressing methodological difficulties of previous studies, the authors investigated the eyeblink, skin conductance and heart rate responses to 15 consecutive 95-dB, 500-ms, 1000-Hz sudden tones in 58 consecutive referrals of unmedicated help-seeking trauma survivors (30 with PTSD and 28 without PTSD). PTSD patients had higher average eyeblink and skin conductance responses to the tones. Differences between reports of exaggerated startle in PTSD and negative experimental findings may be explained by specific experimental conditions, such as reduced environmental input, and by concurrent use of medication.

Adult↗
PubMed1997

Pre-adolescent chumship as a buffer against psychopathology in adolescents with weak family support and weak parental bonding.

This study examines the degree to which the existence of a pre-adolescent "chum" interacts with family and social environments to buffer mental distress in adolescents. 831 high school students participated in this study, (male: 355; female: 476; mean age 16.7 +/- 1.0). Subjects were administered questionnaires assessing psychopathology and support systems. A pathway analyses model was used to investigate pathways and their interrelationships from chum to psychopathology and from social and family support to psychopathology. Only when adolescents experience weak parental bonding does chumship have a role in buffering distress.

Adolescent↗
PubMed1997

Pathophysiological significance of cerebral perfusion abnormalities in major depression-trait or state marker?

Considerable data support the existence of impaired regional cerebral blood flow in major depression. However, it is unclear whether the impairment in brain function in major depression is a "state" marker, reversible upon remission, or an enduring trait phenomenon. We have studied brain technetium-99m hexamethylpropyleneamineoxime (Tc-99m HMPAO) uptake ratios in healthy subjects of various ages, in depressed patients before and after electroconvulsive therapy (ECT) and in healthy subjects before and after administration of fluoxetine. Analysis of our findings, presented along with research data of other groups, strongly suggests that reduced cerebral perfusion in major depression is reversible by successful treatment. Furthermore, since fluoxetine had little effect on cerebral perfusion in healthy subjects, and ECT had little effect on cerebral perfusion in depressed patients who did not respond to treatment, we contend that increases in perfusion represent remission rather than treatment effect. Therefore, reduced perfusion in major depression appears to be a state marker and not a trait abnormality.

Adult↗
PubMed1997

Concurrent treatment of nonresistant major depression with desipramine and lithium: a double-blind, placebo-controlled study.

The objective of this study was to compare the onset, rate of antidepressant (AD) response, and treatment outcome of depressed patients treated for 5 weeks with either the concomitant administration of the tricyclic AD desipramine (DMI) and lithium carbonate (Li) or with DMI alone. In this double-blind, placebo-controlled study, 31 nonpsychotic, mild to moderately depressed outpatients (DSM-III-R unipolar or bipolar major depression) were randomly assigned to 5 weeks of treatment with DMI plus Li (N = 16) or DMI plus placebo (N = 15). Drug dosages were adjusted to achieve therapeutic plasma levels. Clinical state was rated weekly by the Hamilton Rating Scale for Depression, the Clinical Global Impression Scale, a Visual Analogue Self-Report Scale, and an adverse-effect form. Twenty-seven patients completed the study, 12 in the DMI-Li group and 15 in the DMI-placebo group. Four patients dropped out due to adverse events, all from the DMI-Li group. Both groups responded well to treatment, without a significant difference between them in the rate of response of final outcome. Sixty-seven percent (10/15) of the patients taking DMI only and 75% (9/12) of the patients taking DMI plus Li met our response criteria. The combination of DMI and Li was associated with significantly more adverse effects than DMI alone. Concurrent treatment with Li did not demonstrate an enhancement of either DMI's efficacy or its onset of action in these patients, suggesting that this strategy may not confer any additional benefit compared with DMI alone in mild to moderately depressed patients who are not preselected for nonresponse to an AD during their current depressive episode.

Adult↗
PubMed1997

Psychological well-being and ratings of psychiatric symptoms in bereaved Israeli adolescents: differential effect of war-versus accident-related bereavement.

Eight hundred seventy-one Israeli adolescents, 375 boys and 496 girls, mean age 16.7 +/- 1, participated in this study. Twenty-three of them lost relatives in war and 19 in road accidents. All participants were administered the Brief Symptom Inventory (BSI), the General Well-being Scale (GWB), the Parental Bonding Instrument (PBI) and the Perceived Social Support-Family/Friend (PSS-Fa and PSS-Fr) measures. War-bereaved adolescents showed significantly higher scores in psychological well-being (GWB) and significantly lower scores in reported psychiatric symptoms (BSI) than accident-bereaved adolescents. War-bereaved adolescents also had significantly better BSI and GWB scores than the general nonbereaved adolescent population. These results persisted after controlling for family socio-economic status, gender, and the degrees of closeness of the deceased relative. War-bereaved adolescents did not differ either from accident-bereaved adolescents or from the nonbereaved general adolescent population in social and family support systems (PSS-Fr, PSS-Fa) and did not experience different basic parental attitudes (PBI). Results are discussed in terms of the different meanings ascribed to death in battle versus death in a road accident.

Accidents↗
PubMed1997

Physical punishment and signs of mental distress in normal adolescents.

Adolescents (375 males and 496 females) were administered the Brief Symptom Inventory (BSI), the General Well-Being Scale (GWB), the Parental Bonding Instrument (PBI), and two questions about each parent, supplementing the PBI, tapping violent punitive behavior. Signs of mental distress in adolescents and reported physical punishment from parents were analyzed. Results indicated that greater physical punishment was associated with higher levels of psychiatric symptoms and lower general well-being. These results persisted after controlling for parental attitudes, as quantified by the PBI, and socioeconomic status. The findings of this study can contribute to efforts to raise public awareness of the negative consequences of physical punishment on the mental health of children.

Adolescent↗
PubMed1996

Cerebral hypoperfusion in medication resistant, depressed patients assessed by Tc99m HMPAO SPECT.

Functional imaging studies generally show decreased cerebral metabolism and perfusion in depressed patients relative to normal controls, although the location of the deficits varies. We used Tc99m HMPAO SPECT to compare cerebral blood flow in medication resistant, depressed patients and a normal control group. HMPAO uptake ratios (adjusted for age) were significantly lower in the depressed patients in the transaxial slices 4 cm and 6 cm above the orbitomeatal line (OML) on the left side. Examining individual regions of interest (corrected for age and multiple testing), we found significantly lower perfusion in the left superior temporal, right parietal and bilateral occipital regions in the patient group. These findings are in limited agreement with previous HMPAO SPECT studies. Methodological differences between studies, particularly variability in adjusting data for age, lead to a divergence in findings. Future research should seek to standardize protocols and data analysis in order to generate comparable results.

Adult↗
PubMed1996

Behavioral and neurochemical alterations caused by diet restriction--the effect of tyrosine administration in mice.

We have investigated the effect of tyrosine administration on the cognitive and neurochemical alterations caused by diet restriction (DR) in mice, as a possible model for some of the behavioral symptoms of patients with anorexia nervosa. Young female mice were fed to 100, 60, and 40% of the calculated daily nutritional requirements for a period of up to 18 days. Cognitive function was evaluated using a modified eight-arm maze with water as a reward. Animals fed to 60% of controls showed significantly improved maze performance while this was impaired in animals on DR to 40%. However, in these animals, injections of tyrosine (100 mg/kg/day) restored performance. Improved maze performance in the 60% DR and 40% DR + tyrosine animals was related to increased beta:alpha tone in the hippocampus- an area, together with the septum, responsible for spatial learning. This was associated with changes in alpha- and beta-receptor density (Bmax), without affecting affinity (Kd); and increased norepinephrine (NE) in the 40% DR + tyrosine group, and methoxyhydroxyphenylglycol (MHPG) in both groups. In the hypothalamus, the brain area responsible for energy metabolism, there was a progressive increase in alpha:beta tone with increasing DR associated with changes in Bmax. Tyrosine treatment reversed these alterations. Tyrosine improves some of the neurobiological disturbances of DR without causing an increase in body weight. Such a strategy might have important implications for the possible treatment of patients with anorexia nervosa.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1996

Brain SPECT imaging of neuropsychiatric disorders.

Brain imaging has become an integral part of the evaluation of neurological and psychiatric disorders. Functional imaging techniques, SPECT and PET, together with structural modalities, CT and MRI, are widely employed. Functional imaging studies are routinely used in the diagnostic workup of patients with well-characterized neurological disorders, such as epilepsy and brain tumors, and have a growing role in research on psychiatric disorders without known mechanisms such as depression and schizophrenia. Furthermore, many well-defined neurological disorders manifest prominent psychiatric symptomatology which may pose difficulties in differential diagnosis. This review addresses the current knowledge of SPECT findings in patients who present with psychiatric phenomena, associated with disorders at the interface of neurology and psychiatry.

Alzheimer Disease↗