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Biomedical subjects

B Amantea

Publications and source records attributed to B Amantea.

At least 19 recordsLinked to original sources
PubMed2004

Hemodynamic effects of levosimendan in patients with low-output heart failure after cardiac surgery.

Following cardiac surgery, low-output syndrome is relatively common. Since this condition can lead to serious consequences, this postsurgical, low-output state should be reversed whenever possible. Patients with low-output syndrome need drug and fluid management aimed at enhancing cardiac contractility and at facilitating optimal myocardial loading. The objective of this pilot study was to evaluate whether benefits of levosimendan, a new calcium-sensitizing agent approved for treatment of patients with acute exacerbation of chronic heart failure, could be extended to patients with low-output syndrome following cardiac surgery. For this study, each patient was given levosimendan as a loading dose of 12 microg/kg over 10 minutes, followed by a continuous infusion of 0.1 microg/kg/min for 12 hours. Of 11 postsurgical patients with severely impaired cardiac output and hemodynamic compromise, 8 patients (73%) showed evidence of combined hemodynamic improvement (> 30% increase in cardiac index and PCWP corrected to < 18 mmHg) within 3 h after the start of levosimendan infusion. Specifically, cardiac index and stroke volume were significantly increased, while mean arterial pressure, indexed systemic vascular resistance, mean pulmonary pressure, right arterial pressure, and pulmonary capillary wedge pressure were all significantly lowered. Taken together, such changes showed enhanced cardiac output along with significantly decreased preload and afterload--conditions associated with recovery of cardiac function. Levosimendan is thus highly favorable for short-term treatment of patients with low cardiac output following cardiac surgery.

Aged↗
PubMed2000

[Neuronal plasticity and neuropathic pain].

The authors have analysis the physiopathology of neuropathic pain, focusing in particular on the plastic phenomena at the level of the central nervous system. Plastic phenomena take the form of anatomic and neurochemical alterations. In relation to the former, excitatory amino acids play a fundamental role, causing a state of hypersensitivity of N-menthyl-D aspartate (NMDA) receptors (excitation toxicity) which in turn cause the degeneration of inhibitory interneurons localised in the I-III laminae of the dorsal cornu. This hyperactivation is responsible for the presence of a discharge input that lasts for minutes after a nociceptive stimulus, a phenomenon known as long-term potentiation (LTP) on long term depression (LTD). The authors also analysed the role of other neurotransmitters and their possible interactions. Neurochemical alterations are coupled with anatomic modifications, like sprouting, at the level of the dorsal cornu laminae and dorsal root ganglia. These neuroplastic phenomena lead to an alteration in the central mechanisms of pain, for A-fibre mediated mechano-allodynia, a clinical phenomenon that differs from thermal hyperalgesia in both physiopathology and clinical prognosis. The role played by the sympathetic system in neuropathic pain is also discussed. The authors also raise a number of clinical considerations regarding the different nature of spontaneous pain, allodynia and hyperalgesia. New physiopathological knowledge is a useful tool for pharmacological and clinical research, as well as for treatment of syndromes secondary to neuropathic pain.

Animals↗
PubMed1998

Nitric oxide inhibits neutrophil adhesion during experimental extracorporeal circulation.

BACKGROUND: Myocardial and pulmonary injuries often occur after cardiopulmonary bypass, mediated in part by neutrophil activation and adhesion to endothelial cells. The effects of nitric oxide (NO) administration on neutrophil adhesion to endothelial cells after simulated extracorporeal circulation were investigated. METHODS: Two identical extracorporeal circulation circuits were primed with fresh human blood and circulated for 2 h at 37 degrees C. Nitric oxide at a 40-ppm concentration was added to one of the oxygenators in each pair. Neutrophil CD11b/CD18 expression and their adhesion to human umbilical vein endothelial cell monolayers were assayed in leukocytes isolated from samples drawn from the circuit 30, 60, 90, and 120 min after circulation began. In another series of experiments, blocking monoclonal antibodies to both neutrophil CD11b and CD18 were incubated with polymorphonuclear leukocytes after removal from the circuit before the adhesion assay. RESULTS: After 60 min of circulation, the neutrophils from NO-treated circuits showed significantly reduced CD11b/CD18 surface expression compared with the control group. There was also a significant reduction in neutrophil-endothelial adhesion in the NO group after 120 min of circulation. Monoclonal antibodies to both CD11b and CD18 significantly inhibited the adhesion of polymorphonuclear leukocytes at endothelial cells after 120 min of circulation. CONCLUSIONS: These results confirm that neutrophil activation occurs during cardiopulmonary bypass. The addition of NO to the circuits of extracorporeal circulation significantly affects neutrophil adhesion to endothelial cells.

Adult↗
PubMed1997

Tracheal rupture secondary to orotracheal intubation.

A case of tracheal rupture due to orotracheal intubation performed for anaesthesiological procedures is described. It is very likely that this rare complication was favoured by some anatomical factors, which were responsible for a difficult intubation. Tracheal rupture was diagnosed by endoscopy and treated by a decompressive tracheostomy.

Female↗
PubMed1988

Evidence for a differential interaction of buprenorphine with opiate receptor subtypes controlling prolactin secretion.

We studied the effects of various doses of the opiate derivative buprenorphine on serum prolactin levels and whether these effects could be counteracted by pretreatment with the opiate receptor blocker naloxone. The administration of increasing doses of buprenorphine exerted a dual effect on serum prolactin levels. At low doses (3, 10 and 30 micrograms/kg) this agent increased serum prolactin levels. This effect disappeared with increasing doses (100 and 300 micrograms/kg), and at the highest doses (1000 and 3000 micrograms/kg) the levels of serum prolactin decreased. Naloxone (30 mg/kg) decreased serum prolactin levels and reversed both the stimulatory and the inhibitory action of buprenorphine. These data are compatible with the hypothesis that buprenorphine could interfere with two different, but inter-dependent receptors: at low doses the oripavine derivative could act at one receptor site to cause an increase of serum prolactin, whereas at higher doses it could interact with a second site of lower affinity that is responsible for the inhibition of prolactin secretion. When buprenorphine (at high doses) activates the lower affinity site, the interaction with this receptor counteracts and reverses the effects of the high affinity site. On the basis of this hypothesis, naloxone should block both receptors.

Animals↗
PubMed1988

Propofol infusion and auditory evoked potentials.

The effects of propofol on auditory evoked potentials (brainstem and middle latency responses) were recorded in six patients. Two different infusion rates were used, 54 and 108 micrograms/kg/minute. Effects on brainstem responses were not found. Regression of amplitude and latency of middle latency auditory potentials were dose related (p less than 0.01).

Adult↗
PubMed1980

[Preparation of a polyvalent antiserum specific for human muscle proteins. I. Muscle extraction: a macromethod and a micromethod].

Protein metabolism may be upset dramatically by several pathological condition such as starvation, malnutrition, surgical stress. Serum proteins have been investigated in many works but very few studies exist about muscle and organ proteins. This article describes two methods for extraction of muscle water soluble proteins: a macromethod that uses some hundred grams of tissue, and a micromethod that starts from a little muscle biopsia. Extracts have been tested for protein content by electrophoresis on cellulose acetate and isoelectrofocusing on polyacrylamide gel and have shown a rich variety of protein fractions.

Animals↗