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C Vicario

Publications and source records attributed to C Vicario.

At least 19 recordsLinked to original sources
PubMed2006

High-power third-harmonic flat pulse laser generation.

The generation of a high-power laser pulse at 266 nm that is longitudinally shaped according to a prefixed intensity profile is reported. The main features of the pulse shape modifications due to second- and third-harmonic conversions are measured, and the results are in good agreement with the theory. The UV temporal shape depends on the chirp of the fundamental pulse and on the crystal phase-matching angle. Exploiting the large stretching imposed on the third-harmonic signal, we show that the pulse intensity profile can be obtained by spectral single-shot measurements.

Journal Article↗
PubMed2006

[Anterior cervical fusion with tantalum interbody implants. Clinical and radiological results in a prospective study].

Anterior cervical discectomy and interbody fusion (ACDF) is a widely accepted surgical technique in the treatment of cervical disc disease. Tantalum cages have been recently introduced in spine surgery for interbody fusion because of the advantages of their mechanical properties. We present the results of a prospective clinical and radiological study on 24 consecutive patients who underwent an ACDF with tantalum cages. Clinical evaluation was assessed preoperatively and after surgery by a questionnaire that included a Visual Analogic Scale (VAS) of neck and arm pain, the Oswestry Disability Index and the Zung Depression Scale. Results were classified by Odom's criteria. Radiological evaluation included flexion-extension X-rays, and changes in distance between spinous processes and Cobb angle were measured. Postoperatively patients were reviewed 3 and 12 months after surgery. A statistical significative improvement in all clinical data was reported. According to Odom's criteria in 75% of patients the results were considered like excellent or good. Only one case of radiological and clinical pseudoarthrosis was confirmed. No significative differences were reported 3 and 12 months after surgery. Tantalum cages are a very promising and usefull alternative among implants available for ACDF. Compatibility with MRI postoperative studies and the unnecessariness of autograft are some of their advantages.

Adult↗
PubMed2005

Observation of anomalously large spectral bandwidth in a high-gain self-amplified spontaneous emission free-electron laser.

Observation of ultrawide bandwidth, up to 15% full-width, high-gain operation of a self-amplified spontaneous emission free-election laser (SASE FEL) is reported. This type of lasing is obtained with a strongly chirped beam (deltaE/E approximately 1.7%) emitted from the accelerator. Because of nonlinear pulse compression during transport, a short, high current bunch with strong mismatch errors is injected into the undulator, giving high FEL gain. Start-to-end simulations reproduce key features of the measurements and provide insight into mechanisms, such as angular spread in emitted photon and electron trajectory distributions, which yield novel features in the radiation spectrum.

Journal Article↗
PubMed2003

Necrosis of the femoral head after fixation of trochanteric fractures with Gamma Locking Nail. A cause of late mechanical failure.

Cut-out of the lag screw after fixation of trochanteric fractures with intramedullary devices like the Gamma Locking Nail is a well documented cause of late mechanical failure. Avascular necrosis of the femoral head after trochanteric fractures is an uncommon complication and several causes have been described. As far as we know, the relation of the mechanical failure of fracture fixation and avascular necrosis of the femoral head in trochanteric fractures has never been described. We present a study of six consecutive patients who underwent arthroplasty after cut-out of the lag screw fixation of a trochanteric fracture with Gamma Locking Nail. All six femoral heads were studied histologically and a clinical retrospective study was also performed. In all cases, we found homogeneous avascular necrosis of the femoral head; in all but one, revascularisation was present in every area examined. We suggest that after fixation of these trochanteric fractures with the Gamma Locking Nail, there is a transitory ischaemia, if the revascularisation is not enough to provide a strong support for the lag screw, it may result in late mechanical failure in these fractures.

Aged↗
PubMed1996

Lactate spares glucose as a metabolic fuel in neurons and astrocytes from primary culture.

The effect of lactate on glucose metabolism in neurons and astrocytes from primary culture has been studied. The rates of glucose metabolism through the pentose-phosphate shunt, the pyruvate dehydrogenase-catalyzed reaction, the tricarboxylic acid cycle, the total lipogenesis and the synthesis of glycerol-borne lipids in astrocytes were 2-3 fold higher than in neurons. However, the rate of glucose incorporation into sterols and esterified fatty acids was similar in both types of cells. Total glucose utilization was inhibited by lactate to the same extend in both neurons and astrocytes. Lactate strongly inhibited glucose oxidation through the pyruvate dehydrogenase-catalyzed reaction and the tricarboxylic acid cycle, in both neurons (60 and 44%, respectively) and astrocytes (64 and 62%, respectively). Glucose incorporation into sterols and fatty acids was also inhibited by lactate in both neurons and astrocytes (57 and 76%, respectively) while the oxidation of glucose in the pentose-phosphate shunt and the synthesis of glycerol-borne lipids was not significantly affected. These results suggest that in the presence of lactate both neurons and astrocytes can utilize lactate as the major metabolic substrate, sparing glucose for the synthesis of NADPH(H+), ribose-5-phosphate and/or glycerol-borne lipids. An interaction between glucose and lactate metabolism at the level of the pyruvate dehydrogenase-catalyzed reaction is suggested.

Animals↗
PubMed1995

Influence of ozone on haemoglobin oxygen affinity in type-2 diabetic patients with peripheral vascular disease: in vitro studies.

The use of ozone in the treatment of peripheral vascular disease (PVD) is increasing. The purpose of this study was to evaluate the effect of ozone on haemoglobin oxygen affinity in Type-2 diabetic patients with PVD. Twenty diabetic patients presenting with PVD (Clinical stage II-IV according to Fontaine) and 20 non-diabetic healthy matched subjects were studied. In both groups, aliquots of blood were ozonised with mixtures of oxygen-ozone (O2-O3) to reach end-concentrations of 6.5, 13, 26 and 78 micrograms O3 per ml of substrate. At baseline, diabetic patients presented significantly lower haemoglobin oxygen affinity values but higher plasma levels of free haemoglobin and malonyldialdehyde (MDA) than controls. In both diabetic patients and controls, exposure of blood to ozone reduced haemoglobin oxygen affinity in an "all-or-none" fashion, without changing 2-3, diphosphoglycerate concentrations in erythrocytes. Both free haemoglobin and MDA concentrations showed significant, dose-dependent increases after blood ozonisation. Thus, ozone caused a significant increase in oxygen unloading of haemoglobin in both normal subjects and Type-2 diabetic patients with PVD.

2,3-Diphosphoglycerate↗
PubMed1993

Regulation of lactate metabolism by albumin in rat neurons and astrocytes from primary culture.

The possible role played by albumin in regulating brain metabolism during development has been studied. The effects of fatty acid-free BSA on lactate, glucose, 3-hydroxybutyrate, and glutamine oxidation and lipogenesis by rat neurons and astrocytes from primary culture were studied. The rate of lactate oxidation and lipogenesis by neurons and astrocytes in the presence of BSA greatly exceeded that observed for glucose, 3-hydroxybutyrate, or glutamine, suggesting that lactate may be a key substrate for brain development. BSA strongly stimulated the rate of lactate, 3-hydroxybutyrate, and glutamine incorporation into lipids in both neurons (677%, 726%, and 250%, respectively) and astrocytes (415%, 393%, and 215%, respectively), possibly by binding long-chain acyl-CoA excesses, potent inhibitors of acetyl-CoA carboxylase. However, BSA decreased the rate of lipogenesis from glucose in both neurons (34%) and astrocytes (55%), probably by inhibiting glycerol-borne phospholipid synthesis. BSA significantly increased the rates of lactate (61%) and glucose (32%) oxidation by astrocytes but not those of 3-hydroxybutyrate and glutamine, suggesting that BSA may stimulate pyruvate oxidation. However, in neurons BSA did not affect the rate of oxidation of any of the substrates tested, which suggests that pyruvate oxidation is regulated differently in neurons and astrocytes. The results suggest that lactate is the most important substrate for both neurons and astrocytes, stressing the role played by lactate in brain development. Our results also suggest that serum albumin may control brain development by fostering metabolism for growth and differentiation purposes.

3-Hydroxybutyric Acid↗
PubMed1992

Metabolism of lactate in the rat brain during the early neonatal period.

The metabolism of lactate in isolated cells from early neonatal rat brain has been studied. In these circumstances, lactate was mainly oxidized to CO2, although a significant portion was incorporated into lipids (78% sterols, 4% phosphatidylcholine, 2% phosphatidylethanolamine, and 1% phosphatidylserine). The rate of lactate incorporation into CO2 and lipids was higher than those found for glucose and 3-hydroxybutyrate. Lactate strongly inhibited glucose oxidation through the pyruvate dehydrogenase-catalyzed reaction and the tricarboxylic acid cycle while scarcely affecting glucose utilization by the pentose phosphate pathway. Lipogenesis from glucose was strongly inhibited by lactate without relevant changes in the rate of glycerol phosphate synthesis. These results suggest that lactate inhibits glucose utilization at the level of the pyruvate dehydrogenase-catalyzed reaction, which may be a mechanism to spare glucose for glycerol and NADPH synthesis. The effect of 3-hydroxybutyrate inhibiting lactate utilization only at high concentrations of 3-hydroxybutyrate suggests that before ketogenesis becomes active, lactate may be the major fuel for the neonatal brain. (-)-Hydroxycitrate and aminooxyacetate markedly inhibited lipogenesis from lactate, suggesting that the transfer of lactate carbons through the mitochondrial membrane is accomplished by the translocation of both citrate and N-acetylaspartate.

3-Hydroxybutyric Acid↗
PubMed1992

[Hyperbaric oxygen therapy in the treatment of benign intracranial hypertension. Follow-up of a preliminary study].

Preliminary experience of hyperbaric oxygen (HBO) in the treatment of benign intracranial hypertension (BIH) is reported. Fifty-three patients with BIH were observed. They were treated with antiedema non steroid drugs plus rachicentesis, with steroid drugs plus rachicentesis, with lumbar peritoneal shunt and only 8 with HBO. Each patient underwent HBO with 100% oxygen at 2 atmospheres absolute a day for 15 days. In all patients a gradual disappearance of signs and symptoms of elevated intracranial pressure was observed. No lasting effect of treatment were seen after concluding therapy. The effect of HBO in the treatment of BIH has not yet been clarified, but the results can encourage further experience and studies.

Female↗
PubMed1991

Lactate utilization by isolated cells from early neonatal rat brain.

The utilization of lactate, glucose, 3-hydroxybutyrate, and glutamine has been studied in isolated brain cells from early newborn rats. Isolated brain cells actively utilized these substrates, showing saturation at concentrations near physiological levels during the perinatal period. The rate of lactate utilization was 2.5-fold greater than that observed for glucose, 3-hydroxybutyrate, or glutamine, suggesting that lactate is the main metabolic substrate for the brain immediately after birth. The apparent Km for glucose utilization suggested that this process is limited by the activity of hexokinase. However, lactate, 3-hydroxybutyrate, and glutamine utilization seems to be limited by their transport through the plasma membrane. The presence of fatty acid-free bovine serum albumin (BSA) in the incubation medium significantly increased the rate of lipogenesis from lactate or 3-hydroxybutyrate, although this was balanced by the decrease in their rates of oxidation in the same circumstances. BSA did not affect the rate of glucose utilization. The effect of BSA was due not to the removal of free fatty acid, but possibly to the binding of long-chain acyl-CoA, resulting in the disinhibition of acetyl-CoA carboxylase and citrate carrier.

3-Hydroxybutyric Acid↗