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Biomedical subjects

D Marazziti

Publications and source records attributed to D Marazziti.

At least 19 recordsLinked to original sources
PubMed1992

Psychological stress and body temperature changes in humans.

We investigated the possible changes in body temperature, heart frequency, and blood pressure in 22 residents sitting for the yearly exam at the Specialty School of Psychiatry at Pisa University. All subjects were then evaluated 2 or 3 weeks later, in calm situations. In a subgroup, a specific plasmatic diazepam binding inhibitor (BBIA), previously described, was also measured. The results showed that all subjects underwent significant stress-related changes in the parameters studied, which suggest the involvement of different mechanisms in preexam stress.

Adult↗
PubMed1992

Peripheral markers of serotonin and dopamine function in obsessive-compulsive disorder.

In an attempt to clarify the possible role of a serotonergic and dopaminergic dysfunction in obsessive-compulsive disorder (OCD), we measured platelet 3H-imipramine (3H-IMI) binding, serotonin uptake, and platelet sulfotransferase activity in 17 drug-free OCD patients and an equal number of healthy controls. Serotonin uptake and 3H-IMI binding sites in platelets have been shown to constitute peripheral markers of those present in presynaptic serotonergic neurons. Sulfotransferase, an enzyme involved in the catabolism of phenolic compounds and of cathecholamines such as dopamine, has similar kinetic characteristics in brain and platelets. Our results showed a lower number of 3H-IMI binding sites and a higher level of sulfotransferase activity in OCD patients compared with those in controls. These preliminary results suggest involvement of both the serotonin and dopamine systems in OCD.

Adult↗
PubMed1992

Personality features and platelet 3H-imipramine binding.

In an attempt to provide further information on the functions of the serotonergic system in humans, we investigated the possible correlation between a peripheral serotonergic marker, such as platelet 3H-imipramine binding, and the Minnesota Multiphasic Personality Inventory (MMPI) items and scales in a group of 20 healthy subjects. The results showed the presence of significant positive correlation between the maximum binding capacity, a measure of the number of 3H-imipramine sites, and 17 MMPI items suggestive of personality features of self-certainty, feeling of well-being and sense of reality.

Adult↗
PubMed1992

Immune cell imbalance in major depressive and panic disorders.

We investigated subsets of peripheral immunologic cells in 12 drug-free patients affected by major depression according to DSM-III-R criteria, and who had recent evidence of somatic diseases. They were compared with 10 drug-free depressives, with 10 patients with panic disorder, and with 12 healthy volunteers, all without somatic disease. The immune subsets were measured by flow cytometry. The results showed that both groups of depressives had the same abnormalities in immune cells compared with the healthy volunteers or the panic disorder patients; in particular they presented a lower number of CD3+, CD8+ and HLA-DR+. The patients with panic attacks did not differ from healthy controls, except for CD4+ cells which were significantly lowered, even in comparison with the depressive groups. These data, although preliminary and in a small sample, suggest that some immune parameters may be influenced by the presence of a major psychiatric disorder.

Adolescent↗
PubMed1991

Platelet imipramine binding in intensive care unit suicidal patients.

3H-Imipramine binding in relation to serotonergic function was studied in patients hospitalized following a suicide attempt. Comparison with a control group showed a highly significant difference in Bmax values. The results suggest, at least a posteriori, a biological alteration as the basis of suicidal behaviour. Although it is impossible to attribute a suicidal attempt to the alteration or to a predisposing pre-existent condition, this biological marker may be useful in evaluating suicidal risk and also short- and long-term prognosis.

Adult↗
PubMed1991

Aggression and suicide attempts: preliminary data.

The similarities between blood platelets and serotonin (5HT) neurons offer a reliable tool of exploring 5HT system. The aim of our study was to evaluate platelet [3H]imipramine binding in suicide attempters, as compared with depressed patients and healthy controls. In addition, we measured aggressive features in the 3 groups, by a standardized rating scale, the Inventory for assessing different kinds of ostility (QTA). The results showed a significant decrease in the maximum binding capacity (Bmax) of 3H-imipramine binding to platelet membranes in suicide attempters, who also exhibited higher total and single item scores at QTA than healthy controls or depressed patients. Both biological and psychological findings are suggestive of an aggression dysregulation in suicide attempters.

Adult↗
PubMed1991

Serotoninergic dysfunction in bipolar disorder.

The recent discovery of peripheral markers of central neurotransmitter systems has broadened the scope of biological research in psychiatry. Human platelets resemble presynaptic serotoninergic neurons and permit us to investigate the involvement of the serotonin system in the pathophysiology of mood disorders. In particular, platelets show an active uptake of serotonin and the related 3H-imipramine (3H-IMI), similar to cerebral binding sites. We evaluated 3H-IMI binding in a group of 30 bipolar patients as compared with healthy controls. In 20 patients, platelet 14C-5HT uptake was also measured. The results showed no difference in IMI binding parameters between bipolar patients and healthy controls. However, the patients showed a lower Vmax of 14C-5HT uptake than the controls. These findings suggest that bipolarity influences one of the main components of the 5HT transporter complex in platelets.

Adult↗
PubMed1991

Decreased platelet serotonin uptake in bipolar I patients.

The 5HT transporter complex in platelets is similar to that in the brain and thus widely used in biological psychiatry as a peripheral marker of the 5HT system. Our study aim was to measure 14C-5HT uptake parameters (Vmax and Km) in platelets from 12 patients affected by bipolar disorder, as compared with 12 healthy controls. The uptake assay was performed according to the method of Arora and Meltzer (1981). The results showed that the Vmax was significantly lower in bipolar patients than in healthy controls, with no modification of the Km. These preliminary data would indicate therefore that the mechanism of 5HT transport is altered in platelets of bipolar patients.

Adult↗
PubMed1991

Aggression, hyperactivity and platelet imipramine binding.

We measured platelet 3H-imipramine binding parameters in 16 subjects affected by different types of mental deficiency, all characterized by hyperactive and/or aggressive behaviour, and in 16 healthy controls. The patients had a lower maximum binding capacity than the controls, with no difference in Kd, irrespectively of the type of mental disorder. These findings suggest a link between 5-HT disturbances, reflected by reduced imipramine binding sites, and behavioural dyscontrol, expressed as hyperactivity and aggression.

Adult↗
PubMed1991

Analgesia by nefopam: does it act through serotonin?

In an attempt to clarify the possible mode of action of nefopam, a new analgesic compound, the authors tested its effects on imipramine (IMI) binding to platelet membranes. The results showed that nefopam exerted a concentration-dependent inhibition of IMI binding, with a potency comparable to that of tricyclic antidepressants. This finding suggests a possible intervention of serotonergic mechanisms in nefopam-related analgesia.

Analgesia↗
PubMed1990

Replica filter assay of human beta-adrenergic receptors expressed in E.coli.

We have developed a replica filter assay that permits the direct identification of bacterial colonies expressing membrane receptors. E.coli transformed with appropriate phage or plasmid vectors containing human beta-adrenergic receptor cDNAs were grown on LB/agar plates. Bacterial colonies transferred onto nitrocellulose filters showed specific [125I]-iodocyanopindolol binding. beta-adrenergic receptors expressed in bacteria retained their pharmacological properties when transferred onto filters. This strategy, which is considerably simplified and more rapid compared to similar methods based upon expression of receptor genes in eukaryotic cells, may be a useful tool for cloning membrane receptors.

Brain Chemistry↗
PubMed1990

Increased platelet 3H-imipramine binding and monoamine oxidase B activity in Alzheimer's disease.

Several biochemical abnormalities in peripheral tissues have been reported in Alzheimer's disease (AD). With this in mind we studied platelet monoamine oxidase B (MAO B) activity and 3H-imipramine (IMI) binding in both AD patients and healthy subjects and found a significantly higher level of platelet MAO B activity and 3H-IMI Bmax values in the AD patients. In view of the part that MAO B plays in metabolizing serotonin (5HT) and of the relationship which exists between 3H-IMI binding and 5HT uptake, our results would suggest that with AD there occurs a complex dysfunction in the 5HT system, at least at a peripheral level.

Aged↗
PubMed1990

Stress-related changes of benzodiazepine binding inhibitory activity (B.B.I.A.) in humans.

The presence of benzodiazepine binding inhibitory activity (B.B.I.A.) in sera from 44 psychiatric patients and from 14 healthy volunteers, prompted us to investigate whether or not this activity underwent changes in stressful situations. We measured the inhibitory units (IU) of deproteinized sera of 12 subjects, immediately before and 2 weeks after sitting for a difficult university exam. Our results showed significantly higher IU values (i.e., higher B.B.I.A. concentrations) in the samples taken just before the exam. This preliminary finding clearly suggests the involvement of B.B.I.A. in anxiety mechanisms.

Adult↗
PubMed1989

Interaction between the serotonin and dopamine systems in humans: preliminary findings.

The availability of peripheral tools, such as platelet [3H]-imipramine binding and electroretinogram b-wave amplitude, for investigating serotonin and dopamine systems respectively, prompted us to explore the possible relationships between these two systems in a group of 8 healthy drug-free volunteers. The results showed a significant correlation between the peripheral parameters of serotonin and dopamine systems and underline the importance of studying different neurotransmitters at the same time in humans.

Adult↗
PubMed1989

Complement C9 is inserted into membranes in a globular conformation.

Complement component C9 undergoes a major conformational change during its insertion into a biological membrane from a globular to an extended form. At 0 degrees C a single C9 binds but a membrane attack complex (MAC) is not formed. We show that the C9 bound at 0 degrees is accessible to the intracellular space and sensitive to trypsin digestion, suggesting that C9 inserts in its globular state and requires an elevated temperature in order to change conformation.

Animals↗
PubMed1989

Age-related differences in human platelet 5-HT uptake.

Platelet 5-hydroxytryptamine (5-HT) uptake was measured in a group of young healthy volunteers and a group of aged healthy volunteers. Our results show a significant increase in the maximal velocity of uptake (Vmax) in the platelets of aged subjects. This could result in a decreased concentration of extracellular 5-HT in old age. Such reduced levels of 5-HT, if they occurred at 5-HT synapses in the brain, could result in susceptibility to the development of neurological or psychiatric illness.

Adult↗