Exploring Ultracold Collisions in

We investigate ultracold collisions in a novel mixture of ^{6}Li and ^{53}Cr fermionic atoms, discovering more than 50 interspecies Feshbach resonances via loss spectroscopy. Building a full coupled-channel model, we unambiguously characterize the ^{6}Li-^{53}Cr scattering properties and yield predictions for other isotopic pairs. In particular, we identify various Feshbach resonances that enable the controlled tuning of elastic s- and p-wave ^{6}Li-^{53}Cr interactions. Our studies thus make lithium-chromium mixtures emerge as optimally suited platforms for the experimental search of elusive few- and many-body regimes of highly correlated fermionic matter, and for the realization of a new class of ultracold polar molecules possessing both electric and magnetic dipole moments.

Realization of a high power optical trapping setup free from thermal lensing effects.

Transmission of high power laser beams through partially absorbing materials modifies the light propagation via a thermally-induced effect known as thermal lensing. This may cause changes in the beam waist position and degrade the beam quality. Here we characterize the effect of thermal lensing associated with the different elements typically employed in an optical trapping setup for cold atoms experiments. We find that the only relevant thermal lens is represented by the TeO2 crystal of the acousto-optic modulator exploited to adjust the laser power on the atomic sample. We then devise a simple and totally passive scheme that enables to realize an inexpensive optical trapping apparatus essentially free from thermal lensing effects.

NMDA receptors and learning and memory processes.

In the first part of this review studies are considered in which pre- or post-training peripheral or intracerebroventricular administrations of competitive or noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonists were carried out in a variety of animal species tested in different experimental conditions, in order to investigate the effects of these drugs on acquisition and memory processes. In particular, post-training treatments, which are known to affect memory consolidation, ruling out the possible "aspecific effects" linked to the pre-training administrations, show that the NMDA receptor antagonists impair memory in animals tested in various tasks. Memory impairments are also evident when the NMDA antagonists (in particular AP5) are injected into different brain structures, including amygdala and hippocampus. In a second part of this review some recent studies are considered showing the existence of: a) cholinergic-glutamatergic interactions; b) interactions between NMDA receptors and opioid system, and c) interactions between NMDA receptor antagonists (MK-801) and cocaine, in the modulation of memory processes of laboratory animals. The results of some studies showing the involvement of glutamatergic mechanisms in Alzheimer's disease are finally reported, and the therapeutic efficacy of glutamatergic drugs in the treatment of this disease is considered.

Decreased sympathetic inhibition in gastroesophageal reflux disease.

This study was undertaken to evaluate autonomic nervous system function in patients with gastroesophageal reflux disease. Based on clinical criteria, 28 consecutive patients with no history of heart, metabolic, or neurologic disease (mean age 41 y, range 20-62 y) reporting with upper gastrointestinal symptoms typical of gastroesophageal reflux underwent esophageal manometry, ambulatory 24-hour pH study with electrocardiographic monitoring, power spectral analysis of heart rate variability, and cardiovascular tests. Twelve healthy subjects served as controls. A positive result of prolonged esophageal pH study (pH in the distal esophagus less than 4, lasting more than 4.2% of recording time) was observed in 21 patients (reflux group); seven patients were categorized in the nonreflux group. No patient showed arrhythmias or any correlation between heart rate variability changes during electrocardiographic monitoring and episodes of reflux (pH less than 4, lasting more than 5 minutes). A decrease of sympathetic function occurred only in the reflux group (p <0.05) supported by the lower increase of systolic/diastolic blood pressure at sustained handgrip. No other cardiovascular tests showed statistically significant differences in the control or nonreflux groups. Total time reflux showed an inverse correlation with sympathetic function in the reflux group (r = -0.415, p <0.028). We concluded that there is some evidence for a slightly decreased sympathetic function in patients with gastroesophageal reflux disease that is inversely correlated with total time reflux. In these patients, decreased sympathetic function may cause dysfunction of intrinsic inhibitory control with increased transient spontaneous lower-esophageal sphincter relaxations, thus resulting in gastroesophageal reflux disease.

Effects of MK-801 and nicotine combinations on memory consolidation in CD1 mice.

RATIONALE: Recent experiments have shown that pre-trial administrations of nicotine to rats tested in a 16-arm radial maze attenuated the MK-801-induced deficit in both working and reference memory performance. Memory consolidation can be influenced in laboratory animals, by post-training administration of drugs. OBJECTIVE: In the present study we have investigated the effects on memory consolidation of CD1 mice exerted by: a) the non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist MK-801 [(+)-5-methyl-10,11-dihydro-5H-dibenzo-[a,d]cyclo-hepten-5, 10-imine-maleate] b) nicotine, and c) combinations of MK-801 and nicotine. METHODS: Different groups of mice were injected intraperitoneally (IP) with the single drugs and with their combinations, immediately after training in a passive avoidance task. Additional groups of animals were also injected 2 h post-training with the highest effective dose of MK-801 (0.3 mg/kg), with the highest effective dose of nicotine (0.5 mg/kg) or with the combination of an otherwise ineffective dose of MK-801 (0.1 mg/kg) with the highest effective dose of nicotine, respectively. Their performances were compared with those of mice injected with saline, with the vehicle of nicotine and with the other treatment combinations, respectively RESULTS: The results showed that MK-801 exerted deleterious effects, while nicotine exerted facilitatory effects on mice performances. Further, an otherwise ineffective dose of MK-801 (0.1 mg/kg) antagonized the facilitatory effects of nicotine (0.25 and 0.5 mg/kg). In the 2 h post-training injected groups the treatments were ineffective, showing that the immediate post-training drug administrations affected memory consolidation processes. CONCLUSIONS: In conclusion, from the present research, it is evident that NMDA glutamate and nicotinic acetylcholine receptor systems interact in modulating memory consolidation in CD I mice.

Strain-dependent interactions between MK-801 and cocaine on retention of C57BL/6 and DBA/2 mice tested in a one-trial inhibitory avoidance task: involvement of dopaminergic mechanisms.

Two sets of experiments were carried out with C57BL/6 (C57) and DBA/2 (DBA) mice tested in a one-trial inhibitory avoidance task. In the first set C57 and DBA mice were injected posttraining with saline or with the D1 DA receptor antagonist SCH 23390 and then with saline, cocaine (5 mg/kg), MK-801 (0.1 mg/kg), or with a combination of these two drugs. Cocaine enhanced retention in the C57 strain and impaired it in the DBA strain, and MK-801 potentiated the effects of cocaine in both strains. Furthermore, pretreatment with SCH 23390 completely antagonized the potentiation of the effects of cocaine exerted by MK-801. In the second set of experiments mice belonging to these same two strains were injected posttraining with vehicle or with the D2 DA receptor antagonist (-)-sulpiride and then with saline, cocaine (5 mg/kg), MK-801 (0.1 mg/kg), or with a combination of these two drugs. Pretreatment with the D2 DA receptor antagonist completely antagonized in both strains the potentiation of the effect of cocaine exerted by MK-801. The results of the present research show that the noncompetitive NMDA receptor antagonist MK-801 enhances the effect of cocaine on retention performance in C57 and DBA mice and that dopaminergic mechanisms are involved in this potentiation.

Strain-dependent effects of MK-801 on passive avoidance behaviour in mice: interactions with morphine and immobilization stress.

RATIONALE: Post-training treatments (drugs, stress, ECS) influence retention performance of laboratory animals, sometimes in a strain-dependent way. In a previous study, an interaction between the effects of morphine and of the non-competitive N-methyl-d-aspartate (NMDA) receptor antagonist MK-801 on retention performance was observed, in random bred mice. OBJECTIVE: In the present research, we have investigated the effects on retention of C57BL/6 (C57) and DBA/2 (DBA) mice exerted by a) morphine, b) MK-801 and c) naltrexone. Further, we have studied in both strains the effects exerted on retention by combinations of morphine and MK-801, and of MK-801 and immobilization stress. Finally, the naltrexone-reversibility of the interaction between immobilization stress and MK-801 was also assessed. METHODS: All treatments were administered immediately after training in mice tested in a passive avoidance task. Drugs were injected IP. RESULTS: The results of our experiments showed that morphine and the non-competitive NMDA receptor antagonist MK-801 exerted dose- and time-dependent facilitatory effects on retention performance in C57 mice, and dose- and time-dependent impairments in DBA mice. Further, dose- and time-dependent deleterious effects on retention performance, in the C57 strain, and dose- and time-dependent enhancing effects, in the DBA strain, were observed following post-training IP naltrexone administration. MK-801 enhanced, in both strains, the effects of morphine. Finally, immobilization stress enhanced in both strains the effects of MK-801 and these effects were naltrexone-reversible. CONCLUSIONS: In conclusion, the results of this study show that the genetic make-up of the mice played an important role in all the effects observed, and, in particular, in the interaction between the opioid and the glutamatergic systems. Further, the naltrexone reversibility of the interaction between MK-801 and immobilization stress suggests that opioid mechanisms were involved.

MK-801-induced disruptions of one-trial inhibitory avoidance are potentiated by stress and reversed by naltrexone.

Five experiments were carried out to investigate opioid and NMDA receptor-mediated responses to one-trial inhibitory avoidance training in CD1 mice. In the first experiment immediate posttraining intraperitoneal administration of the noncompetitive N-methyl-d-aspartate (NMDA) receptor antagonist MK-801 impaired the performance of mice. The effects of MK-801 were time-dependent (they were absent in mice injected with the drug starting 120 min after training). No effect was evident in no-foot-shock groups, showing lack of proactive influence of the treatment on performance. In the second experiment preexposure of the mice to the testing apparatus decreased the effects of MK-801. In the the third experiment naltrexone antagonized the effects of MK-801, suggesting an involvement of opioid neurons. In the fourth experiment immediate posttraining immobilization stress exerted a potentiating effect on the performance of MK-801-injected animals. In the fifth experiment the potentiation of the impairing effect of MK-801 induced by immobilization stress was antagonized by naltrexone.

[Chronobiological standards of 24-hour arterial blood pressure validated by bayesian criteria]. / Standard cronobiologici della pressione arteriosa di 24-h stimati con criteri bayesiani.

The monodiagnosis of hypertension via ambulatory (A) blood pressure (BP) monitoring (M) is erroneous by definition. Its use has to be substituted by the chronodiagnosis. Because of the lack of an international standardization, the BP chronobiologic reference limits have to be computed on a small sample size. For this compilation, it is, however, unavoidable the recruitment of normotensive subjects using the WHO's fixed limits. These chronobiologic standards are by principle contaminated by false negatives and need a bayesian validation. Such a depuration has been made by reclassifying each subject using the BP time-qualified standards. A secondary sample was constituted on the true normotensive reclassified. This sample provided the a posteriori reference standards for BP. The bayesian chronobiologic reference standards seem to be the limits with which the chronodiagnosis of hypertension can be suitably done via ABPM.

Blood pressure 24-hour pattern in two industrialized countries (Italy and Japan) with a different culture in salt intake.

This study investigates the blood pressure (BP) 24-hour pattern in representative samples of 2 industrialized countries, Italy and Japan, showing different cultures in salt intake. BP was monitored by means of a noninvasive ambulatory device whose readings were analyzed by means of chronobiometric procedures. The results show that the 24-hour BP pattern is not substantially different in Italian and Japanese subjects. In particular, the expected lower BP in the Italians was not detected despite their lower salt intake. Because the 24-hour mean BP value was seen not to be proportional to salt intake, the hypothesis is formulated that maintenance of the pressure regimen within a given range of variability is a principle of human physiology. To comply with this rule the Japanese people are supposed to have ethnically developed a certain resistance to dietary salt for which their cardiovascular apparatus is protected (phyletic escape to dietary sodium excess).

Circadian rhythm of blood pressure and heart rate in cardiopathic patients before and after heart transplantation.

The aim of this study was to investigate the natural history of the circadian rhythm of blood pressure (BP) and heart rate (HR) in 10 patients with heart failure (class IV of the New York Heart Association), who underwent heart transplantation because of primary congestive cardiomyopathy. The control group was 10 age-matched clinically healthy subjects. The BP and HR monitorings were performed before and after transplantation. Preoperatively, analysis of variance and cosinor methods validated the occurrence of a statistically significant BP and HR circadian rhythm in cardiopathic patients. Over the 4 days after surgery, both the cosinor method and serial section analysis were unable to validate a 24-h periodicity for BP and HR in patients with heart transplants. Six months after surgery, the BP and HR circadian rhythm was not detected as well. One year after transplantation, the BP and HR circadian rhythm was statistically validated. The recovery of the BP and HR circadian rhythm 1 year after heart transplantation can be regarded as a clinical sign of a reacquired susceptibility to neurovegetative chronoregulation.