PubMed Health⌕ Search

Biomedical subjects

D Dassa

Publications and source records attributed to D Dassa.

15 recordsLinked to original sources
PubMed1997

Red blood cell L-tryptophan uptake in depression. II. Effect of an antidepressant treatment.

The evolution of the kinetic parameters, maximal velocity (Vmax) and Michaelis constant (Km), of L-tryptophan (L-TRP) uptake into red blood cells (RBC) was studied in 30 depressed patients in a drug-free state (D0) and after 1 week (D7) and 4 weeks (D28) of a treatment involving a variety of antidepressant drugs, including SSRIs and tricyclics. At D0, 76% of patients exhibited abnormal values of Vmax, which were either higher (36%) or lower (40%) than the control range (control Vmax mean +/- 1 S.D.). High and low Km values were observed in parallel with high and low Vmax values. At D7, individual values of Vmax varied drastically compared to their corresponding value at D0, whatever the pretreatment value of the parameter. The magnitude of the Vmax variation during the first week of treatment was found to be significantly larger in the treatment responders than in the non-responders. At D28, Vmax values of all the responders to treatment were within the control range, whatever their pretreatment Vmax value. On the contrary, non-responders had Vmax values that were significantly lower than those of the controls. Changes in Km followed changes in Vmax during antidepressant treatment. In conclusion, normalization of L-TRP transport kinetics was concomitant with a clear alleviation of depressive symptoms, indicating that RBC L-TRP uptake is dependent on clinical state. Moreover, early reactivity of the Vmax as soon as the first week of treatment may be useful as a predictive index of clinical outcome at D28.

Adolescent↗
PubMed1996

Relationship of birth season to clinical features, family history, and obstetric complication in schizophrenia.

Birth in late winter and spring has been consistently shown to be a risk factor of schizophrenia. The relationship of late winter/spring birth to clinical characteristics and other putative risk factors, such as family history and obstetric complications, may provide clues to etiology. Data relating to season of birth, clinical features, family history, and obstetric complications were analyzed for 192 patients with schizophrenia as defined by Research Diagnostic Criteria (including schizoaffective disorder). There was no significant association of season of birth with any of the psychopathological dimensions nor was there a significant association with obstetric variables or family history. However, winter-born schizophrenic patients who had a negative family history were more likely to have a history of obstetric complications. These findings suggest that obstetric complications associated with schizophrenia are perhaps the result of some seasonal risk factors important in those without a family history of the disorder.

Adolescent↗
PubMed1996

Red blood cell L-tryptophan uptake in depression: kinetic analysis in untreated depressed patients and healthy volunteers.

Kinetic parameters (Vmax and K(m)) of L-tryptophan (TRP) uptake into red blood cells (RBC) were measured in 72 drug-free depressed inpatients and 35 healthy volunteers. Mean Vmax and K(m) values were not significantly different between patients and volunteers. The frequency distributions of Vmax values, however, largely differed in the two groups: Vmax values were homogeneous in the volunteers while they were widely scattered in the depressed patients. Only 15 out of the 72 depressed patients (21%) had Vmax values within 1 SD from the mean control value. Forty-four percent of the patients (n = 32) had Vmax values above the control mean + 1 SD in 11 patients and above the control mean + 2 SD in 21 patients. Thirty-five depressed patients (n = 25) had Vmax values below the control mean - 1 SD in 8 patients and below the control mean - 2 SD in 17 patients. High and low K(m) values were observed in combination with high and low Vmax values. The alterations in kinetic parameters were neither associated with severity of depression nor with a specific diagnostic subtype of depression. The data show abnormalities in RBC L-TRP uptake in most depressed patients that likely reflect a disturbance in peripheral availability of TRP on which central serotonin synthesis closely depends.

Adolescent↗
PubMed1996

Elevated circulating levels of IL-6 in schizophrenia.

Schizophrenia may result from immune or inflammatory disorders, which are mediated by cytokines. Data in this field are heterogeneous and often contradictory. We investigated circulating levels of IL-6 and TNF-alpha, two distinct proinflammatory cytokines. Using immunoassay, we assessed IL-6 and TNF-alpha in serum from chronic schizophrenic patients (n = 30) and normal controls (n = 15). Circulating levels of IL-6 were higher in patients than in controls; those of TNF-alpha were not significantly higher than in controls. In addition, IL-6 levels were higher in patients with acute exacerbation of schizophrenia than in patients with remissions. Our results suggest that immunologic abnormalities in schizophrenia may be related to a specific inflammatory process mediated by IL-6. An interesting line of research would be the evaluation of IL-6 cerebral production in CSF.

Adult↗
PubMed1996

Season of birth and schizophrenia: sex difference.

1. A statistically significant increased risk of schizophrenia for individuals born in winter has been reported. The increase risk is of the order of 5-15 percent. The seasonal effect is more marked among females. This winter birth effect suggests some environmental agents, probably a neuropathogen one, acting on the foetus. 2. The present study sought to test the environmental damage hypothesis by application of the family history of psychiatric disorder distinction to season of birth data divided according to sex and using a control population. 3. From computer records, all patients admitted to the psychiatric department of Marseilles Timone hospital between January 1984 and December 1989 who satisfied DSM III, DSM III R criteria for schizophrenia were identified. Patients were then classified into two groups: family history of psychiatric disorder versus no family history. Division according to the sex was carried on after two groups were formed. 4. The data show (I) a significant excess of births in the early months of the year (p < 0.05) for all patients with no family history of psychiatric disorder, (2) a significant excess of births for females (p < 0.05) with no family history. 5. These results provide indirect support for the neurodevelopmental theory of schizophrenia.

Adult↗
PubMed1995

Decrease in red blood cell L-tryptophan uptake in schizophrenic patients: possible link with loss of impulse control.

1. Kinetic parameters of erythrocyte L-tryptophan (TRP) uptake (Vmax, maximal velocity and Km, Michaelis constant) were determined in 19 neuroleptic-free schizophrenic patients and in 19 healthy volunteers. Both Vmax and Km values were significantly lower in schizophrenic patients than in controls. 2. Mean Vmax value was found to be lower in patients who had attempted suicide than in patients who had not. No difference was observed when patients were subdivided on the basis of the violence of suicide attempts. 3. A significant negative correlation was observed between Vmax and scores on the loss of impulse control item as assessed on the PANS scale. 4. Decrease in red blood cell L-TRP uptake reflects a disturbance in the peripheral metabolism of TRP that may result in a deficiency of the plasma L-TRP availability on which the central serotonin (5HT) synthesis closely depends. 5. In addition, the results suggest that the alteration in RBC L-TRP uptake is associated with loss of impulse control in schizophrenic patients.

Adult↗
PubMed1995

No association between prenatal exposure to influenza and autism.

We examined the relationship between the number of autistic patients, obtained from the register of the National Autism Society (NAS), born each month between January 1953 and December 1988 in England, and the occurrence of influenza epidemics one to nine months before birth. The relative risk of developing autism, for exposure to influenza during gestation, was assessed by a Poisson regression model. Our results indicate that exposure to influenza epidemics during gestation is not associated with autism.

Adolescent↗
PubMed1995

[New neuroleptic agents and new models for psychoses].

Atypical neuroleptics can be defined as dopamine receptor blockers which differ from typical neuroleptics in that they have a markedly lower or absent propensity for the induction of parkinsonian side effects or tardive dyskinesias. The authors are studying varied molecules considering their mechanism of action. The differences between atypical and typical neuroleptics may relate to regional specificity in site of actions and receptor binding profile. The authors insist on clozapine, which is a D2 antagonist and in which many other systems might be involved. New neural models may help understand these interactions. The Swerdlow and Koob's model is a unified hypothesis of cortico-striato-pallido-thalamic function which can explain psychoses, depression, dyskinesias and Parkinsonian disorders. The authors make a linkage between this model and Davis's hypothesis. This author hypothesizes that schizophrenia is characterized by abnormally low prefrontal dopamine activity leading to excessive dopamine activity in mesolimbic dopamine neurons, that explains the both negative and positive symptoms coexistence. For the authors, new ways are then opened for an integrative conception of psychosis and affective disorders. This conception might be integrated into the bio-psycho-social model based on chaotics, evocation of which is the author's conclusion.

Antipsychotic Agents↗
PubMed1994

Lack of association between platelet tritiated imipramine binding and clinical status of depressed patients on chronic antidepressant treatment.

Platelet tritiated imipramine binding (Bmax) was studied in 33 depressed patients, before and after 1 and 4 weeks of antidepressant treatment, and in 34 healthy volunteers. The Bmax was significantly lower (-21%) in drug-free depressed patients than in controls and increased significantly as early as the first week of treatment to reach the control value, in parallel with a 38% decrease in the Hamilton depression rating scale (HDRS) score. After 4 weeks of treatment, the Bmax was still normal and remained significantly higher than the baseline value, while the clinical state of the patients had greatly improved (a 63% decrease in the HDRS score). However, an increase in the Bmax also occurred in non-responders to treatment. In addition, we observed that the ability of the treatment to increase the Bmax depended on the pharmacological profile of the drug used. The present results show that, in patients on antidepressant medication, platelet tritiated imipramine binding normalization cannot be considered as a marker of clinical remission.

Adult↗
PubMed1993

Evidence for a defective platelet L-tryptophan transport in depressed patients.

The kinetic characteristics of platelet L-tryptophan uptake were investigated in 23 untreated depressed patients and 18 healthy volunteers. A significant increase of 50% in the apparent Michaelis constant (Km) was observed in depressed patients compared with controls, without significant change in the maximal velocity (Vmax). After 1 month of successful antidepressant treatment the mean Km value decreased significantly and reached the control value. This result raises the possibility that the decrease in platelet tryptophan uptake affinity is a state-dependent marker for depression. It is likely that the transport alteration results in a decrease in platelet tryptophan accumulation. The effect of this peripheral membrane defect on brain serotonin function is discussed.

Administration, Oral↗
PubMed1993

Clozapine in the treatment of psychotic refractory depression.

A 40-year-old woman suffering from major depression with psychotic features was unresponsive to conventional therapy. After the administration of a wide range of drug treatments and ECT, she received clozapine. Depressive symptoms improved and psychotic features disappeared. It is suggested that clozapine could be efficient in psychotic refractory depression.

Adult↗
PubMed1992

[The atypical neuroleptic concept].

Atypical neuroleptics can be defined as dopamine (DA) receptor blockers which differ from typical neuroleptics in that they have a markedly lower or absent propensity for the induction of parkinsonian side effects of tardive dyskinesias. Some of them, but not all, are also more effective in treating schizophrenic patients, i.e. those with negative symptoms or who resist to classical treatments. There may be four classes of potential atypical neuroleptics: 1) Antipsychotics such as sulpiride and remoxipride that block a subgroup of D2 receptors; 2) D1 antagonists that may prove to be a valuable new type of antipsychotic drug; 3) Partial D2 agonists and 4) Antipsychotics such as clozapine and risperidone which block DA as well as other receptors and which appear to have the most pronounced antipsychotic effect. The differences between typical and atypical neuroleptics may first relate to regional specificity in site of actions. Animal studies suggest that atypical neuroleptics may act preferentially on mesolimbic and mesocortical as opposed to striatal DA systems. Most studies which have attempted to define the biological mechanisms which subserve the differences between atypical and typical neuroleptic drugs have focused on receptor binding profile of these drugs. Relatively higher affinity for the serotonin (5HT2) receptor than for the D2 receptor may be important to the action of clozapine-like compounds. However, many other systems might be involved and it seems likely that the atypical neuroleptic profile could be achieved in more than one way.(ABSTRACT TRUNCATED AT 250 WORDS)

Antipsychotic Agents↗