Biomedical subjects
Publications and source records attributed to P Zanardi.
The physical resources available to access and manipulate the degrees of freedom of a quantum system define the set A of operationally relevant observables. The algebraic structure of A selects a preferred tensor product structure, i.e., a partition into subsystems. The notion of compoundness for quantum systems is accordingly relativized. Universal control over virtual subsystems can be achieved by using quantum noncommutative holonomies
An all optical implementation of quantum information processing with semiconductor macroatoms is proposed. Our quantum hardware consists of an array of quantum dots and the computational degrees of freedom are energy-selected interband optical transitions. The quantum-computing strategy exploits exciton-exciton interactions driven by ultrafast multicolor laser pulses. Contrary to existing proposals based on charge excitations, our approach does not require time-dependent electric fields, thus allowing for a subpicosecond, decoherence-free, operation time scale in realistic semiconductor nanostructures.
The role of dopamine (DA) in the secretion of GH in most animal species is still controversial. We examined in the dog the effect on GH release of nomifensine, a drug which activates both noradrenergic and dopaminergic neurotransmission. Nomifensine (0.4-2.8 mg/kg, iv), administered into 12 unanesthetized male and female beagles, induced short-dose-related rises in canine GH (cGH) levels. Blockade of alpha-adrenergic receptors by phentolamine prevented the GH stimulatory effect of 2.8 mg/kg nomifensine, and an iv bolus injection of haloperidol (a neuroleptic which antagonizes both norepinephrine and DA receptor function) given 45 min before was equally effective. Selective blockade of DA receptors by pimozide significantly reduced the GH-releasing effect of nomifensine. In sum, these data indicated that the effect of nomifensine was the consequence of an enhanced noradrenergic and dopaminergic-neurotransmission. Pretreatment with domperidone, a DA receptor blocker unable to cross the blood-brain barrier, failed to modify the GH-releasing effect of nomifensine, suggesting that the DA component subserving the neuroendocrine effect of the drug lies within the blood-brain barrier. Further evidence for a stimulatory role of DA on GH release was the fact that apomorphine, a direct stimulant of DA receptors, induced a rise in cGH levels when administered to dogs pretreated with domperidone. The latter drug was used to prevent emesis and distress due to activation of peripheral DA receptors by apomorphine. However, apomorphine was only active in the dog at doses (250 and 500 microgram/kg, sc) greatly exceeding those active in releasing GH in man, suggesting that the role of DA in cGH regulation is ancillary to that exerted by noradrenergic neurotransmission. In a final study, atropine, a muscarinic cholinergic receptor antagonist, abolished the neuroendocrine effect of nomifensine, a finding which suggests that cholinergic medication plays an important role in cGH regulation.
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In the Ferrara province of Italy, a screening programme for the detection of breast cancer was initiated in 1965; by 1976, 21,120 women had been examined. The biologic history of the women participating in the program is routinely collected at registration. Several biological variables can be extracted from the history. We used 15 biologic variables in order to construct discriminant functions between women affected by breast cancer and a group of control women. It was found that four variables suffice to separate the group of the women with breast cancer from the control group, although with some degree of uncertainty. The theory was advanced that the individual values of a discriminant function may be associated with the risk of healthy women for developing breast cancer. Data collected after the construction of the discriminant function hint at such an association. We have attempted to calculate a discriminant value for healthy women participating in screening programs, so that those having a discriminant value below a given threshold may be considered at higher risk than those above the threshold. The women in the high-risk group may then be submitted to an appropriate examination schedule.
The endocrinological actions of quipazine, a direct serotonin receptor agonist, were investigated in both normal subjects (NS) and individuals with neurological disorders, i.e., Huntington's disease (HD), myoclonic epilepsy (ME) and cluster headache (CH). In both normal subjects and neurologic patients inconsistent and variable changes in the secretion of anterior pituitary hormones were observed. In fact, oral administration of 50 mg of quipazine elicited a rise in plasma GH in only 9/23 subjects investigated (3 NS, 2 HD, 1 ME, 3 CH), decreased GH in 4 subjects (1 NS, 2 HD, 1 CH) and left unmodified plasma GH in the remaining 10 subjects. Only 7/23 subjects showed a positive PRL response to quipazine (2 NS, 1 HD, 1 ME, 3 CH), in one subject (CH) PRL was inhibited while the drug was ineffective in the remaining 15 subjects. For gonadotropins, 5/21 subjects (2 NS, 1 HD, 2 CH) had a positive LH response and 3/20 subjects (1 NS, 1 ME, 1 CH) had a positive FSH response. In one subject (HD) there was inhibition of baseline LH levels and no effects were present in the remaining individuals. No changes in basal TSH levels were present in the 6 subjects investigated (4 NS, 2 ME). Quipazine was instead competent to increase plasma cortisol levels in 6/8 normal subjects. Pharmacodynamic, mainly gastrointestinal, effects of the drug were present in about 50% of the subjects but were not or only poorly correlated with the endocrine responses. Collectively, based on the neuropharmacologic profile of the drug, and in contrast to many animal data, these findings do not support a major role for the serotoninergic system on basal anterior pituitary hormone secretion in man, possibly with the exception of the ACTH-cortisol secretion.
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The ABO and Rh systems of the population in 26 residential units in the province of Ferrara were studied to detect the effect of genetic drift on the differentiation of gene frequencies. Results obtained from principal components analysis and dendrograms were similar. A significant correlation between genetic and geographic distance was found. It was therefore hypothesized that in the area of Ferrara children born to parents originating from different communes were heterozygous at more loci than children born to parents originating from the same commune. It was also thought that it may be possible to use geographic distance between birthplaces of parents as an indicator of hybridity in their children.