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Biomedical subjects

G Giron

Publications and source records attributed to G Giron.

At least 19 recordsLinked to original sources
PubMed2002

ALEX (artificial liver for extracorporeal xenoassistance): a new bioreactor containing a porcine autologous biomatrix as hepatocyte support. Preliminary results in an ex vivo experimental model.

Long-term maintenance of viability and expression of differentiated hepatocyte function is crucial for bioartificial liver support. We developed a new bioreactor design (ALEX), associated with a new extracellular autologous hepatocyte biomatrix (Porcine Autologous Biomatrix - PBM) support. To test this new bioreactor, we compared it to a standard BAL (BioArtificial Liver) cartridge in a ex vivo model using human plasma added to bilirubin, ammonium and lidocaine. A pathology study was performed on both bioreactors. The results suggest that ALEX allows a maximal contact between the perfusing plasma and the liver cells and a proper hepatocyte support by a cell-to-matrix attachment. ALEX is a suitable cell support bioreactor, guaranteeing long-term maintenance of the metabolic activity of hepatocytes when compared to a standard BAL cartridge.

Ammonia↗
PubMed2001

Tranexamic acid in aortic valve replacement.

OBJECTIVE: To assess the relative efficacy of tranexamic acid compared with a control group to decrease bleeding and transfusion requirements in a uniform population undergoing aortic valve replacement. DESIGN: Prospective, randomized, double-blind study. SETTINGS: University hospital. PARTICIPANTS: Adult cardiac surgery patients (n = 300). INTERVENTIONS: Patients were randomized into 2 groups to receive either a total of 5 g of tranexamic acid or a saline solution. Bleeding in the postoperative period, transfusions of bank blood products, coagulation profile, intensive care unit stay, and hospital length of stay were recorded. MEASUREMENTS AND MAIN RESULTS: Postoperative bleeding in patients treated with tranexamic acid was significantly lower compared with the control group (p < 0.0001). Packed red blood cells and fresh frozen plasma usage were reduced in the tranexamic acid group compared with the control group (p = 0.0095 and p < 0.0001). Only 24.5% of tranexamic acid patients received blood products versus 45% of control patients (p < 0.01). There was no significant difference in hematologic and coagulation profiles after the operation between the groups. CONCLUSIONS: Tranexamic acid reduces postoperative blood loss and transfusion requirements in elective aortic valve replacement.

Aged↗
PubMed2000

Variables of stimulation and placebo in acupuncture reflexotherapy.

Placebo can be defined as "the idea of recovery." It represents the natural impulse toward recovery that is catalyzed by treatment or even simply by the idea of treatment. Therefore, placebo is not an "active" treatment; it is used in scientific research to discriminate between the actual effect of a drug or therapeutic technique and the result of chance or the will to recover. Even though it is only an idea, placebo can cause improvement and recovery in approximately 30% of the subjects treated with any therapeutic program and for very different pathologies. Acute pathologies are more sensitive to placebo than chronic ones; functional disorders respond better than organic alterations, and so on. The main controversial issues in the methodology of acupuncture research are: placebo, double-blinding, and the intensity of stimulation of needles. The most used placebo method is sham acupuncture, which is the insertion of the needles outside acupuncture points. It is argued that this methodologically incorrect choice leads to studying the importance of the acupuncture point, rather than that of acupuncture as a transdermic stimulation technique.

Acupuncture Therapy↗
PubMed1999

Different analgesic effects of manual and electrical acupuncture stimulation of real and sham auricular points: a blind controlled study with rats.

Stimulation of the auricle is considered to be an effective analgesic technique. The aim of the present study is to establish whether there is a correspondence between somatic inflammation and the appearance of lower resistance points, and moreover, whether the stimulation of such points has an analgesic effect. The study has been conducted on 57 male Sprague-Dawley rats weighing between 120-140 g; 7 of them have been used to determine whether inflammation in the paw leads to the formation of lower resistance points on the auricle. The 50 remaining animals have been divided into 5 groups: Group 1 [12 animals], control were subjected to all manipulations with the exception of the auricle stimulation; Group 2 [12] was stimulated with manual acupuncture in the area corresponding to that observed in the above-mentioned first group of 7 animals; Group 3 [12] was stimulated with 5 Hz and 5 mA; electroacupuncture (EAP) Group 4 [8] and group 5 [6] were treated with acupuncture and with EAP respectively on points believed to be inactive in areas diametrically opposite to the ones observed in the first group. After acupuncture, 100 microg capsaicin in 50 microL of physiological solution were injected subcutis in the dorsal surface of the paw. Edema response was monitored for two hours, with measurement taken every 5 minutes. The results show a reduction in the edema response, only in the group treated with EAP on the appropriate points compared to the control group; no variation was observed in the sham groups. To conclude, the hypothesis of a somatotopic division would seem to be probable, and it would seem that the stimulation of the appropriate areas and the use of an appropriate intensity constitute the two main variables influencing the result.

Acupuncture Analgesia↗
PubMed1998

99mTc-HMPAO SPECT in the diagnosis of brain death.

OBJECTIVE: To evaluate the effectiveness of single proton emission tomography (SPECT) with 99mTc-HMPAO in the diagnosis of brain death (BD). DESIGN: Prospective study in comatose and brain-dead patients. SETTING: Neurologic ICU. PATIENTS AND METHODS: Fifty comatose patients (age range: 10 days-75 years) were submitted to SPECT study. In 21 of them (42%) reversible factors (e.g., influence of drugs affecting the central nervous system) were present. Thirty-eight patients were clinically brain-dead, while the remaining 12 were tested both in pre-terminal conditions and after the clinical onset of BD. INTERVENTIONS: Brain SPECT following i.v. injection of 99mTc-HMPAO (300-1100 MBq), using a 4-headed gamma-camera (20 min, 360 degrees, 88 images). MEASUREMENTS AND RESULTS: All patients tested in pre-terminal conditions showed preserved brain perfusion. Two of them had flat EEGs despite the absence of any reversible cause of coma; three patients survived, but remained in persistent vegetative states. SPECT confirmed the diagnosis of BD in 45 out of 47 patients (95.7%), clearly showing the arrest of brain perfusion (picture of "empty skull"); in two clinically brain-dead children (aged 10 days and 12 months, respectively) weak perfusion of the basal ganglia, thalamus and/or brain stem was still present, precluding the diagnosis of BD; both of them died a few days later. CONCLUSIONS: Our results confirm the reliability of SPECT in the diagnosis of BD. A problem arises about its effectiveness in brain-dead children, but this seems to be a matter of definition of BD and cerebral viability, rather than a limit of SPECT.

Adolescent↗
PubMed1998

Analgesic effect of subcutaneous administration of oxygen-ozone. A blind study in the rat on the modulation of the capsaicin-induced edema.

The Authors have explored a new complementary approach, employed in the last 40 years for, among other uses, medical purposes: oxygen-ozone therapy. Anecdotal works have highlighted interesting results obtained in disk herniation with infiltration of paravertebral muscles with oxygen-ozone. To verify the existence of a nociceptive effect and investigate a possible mechanism of action, an experimental model of edema induction by subcutaneous capsaicin injection in the rat paw was employed. Oxygen-ozone, in different concentrations (10 microg/ml, 20 microg/ml and 30 microg/ml) has been injected both ipsi- and contralaterally to the paw 30 minutes before the administration of 50 microg capsaicin in 50 microl of physiological solution. Results show that the contralateral injection of the O2-O3 mixture modulates the edema response in the paw. Statistical significance, for the 20 microg/ml mixture, lasts as far as 45 minutes after administration of the capsaicin. No efficacy has been found for the 10 and 30 microg/ml concentrations. An injection of the same quantity of gas in the ipsilateral paw to the capsaicin-induced edema determines a worse edema than that observed in the control group, as if the ozone mixture added its irritative effect to that of capsaicin. It is interesting to note that the administration of oxygen alone cause a greater edema than the oxygen-ozone mixture.

Acupuncture Analgesia↗
PubMed1998

Effects of deep vs. superficial stimulation of acupuncture on capsaicin-induced edema. A blind controlled study in rats.

The modality of needle stimulation in acupuncture is part of the concept of the ìintensityî of the stimulation, a variable indicating the ìdosageî of the treatment administered. In this study we intend to compare the effect of superficial and deep needle insertion in the leg ipsilateral or contralateral to the paw treated with capsaicin. Testing was carried out on 100 male Sprague-Dawley rats weighing 120-140 g, divided into 5 groups according to the treatment received. Group 1 [20 animals] was kept as control; Group 2 [20] received ipsilateral deep acupuncture stimulation; Group 3 [20] received ipsilateral superficial acupuncture stimulation; Group 4 [20] received contralateral deep acupuncture stimulation; Group 5 [20] received superficial contralateral acupuncture stimulation. Results show that both acupuncture modalities are efficient when administered ipsilaterally to the paw where capsaicin is injected, while contralaterally only deep stimulation shows a certain efficiency. It is possible to conclude that deep insertion has a greater efficiency, probably because it affects a greater number of receptors; stimulation is therefore of an intensity greater than that seen in superficial insertion.

Acupuncture Therapy↗
PubMed1997

Intraoperative plasmapheresis in cardiac surgery.

OBJECTIVE: To determine the effects of intraoperative plasmapheresis on total transfusion requirements, mediastinal drainage, and coagulation. DESIGN: The trial was prospective, randomized, and controlled. SETTING: Inpatient cardiac surgery at a university medical center. PARTICIPANTS: Two hundred ninety-three consecutive patients undergoing cardiac surgery requiring cardiopulmonary bypass. INTERVENTIONS: Intraoperative plasmapheresis (IP) was performed in 147 patients before heparinization; platelet-rich plasma was reinfused immediately after heparin reversal. MEASUREMENTS AND MAIN RESULTS: Mediastinal chest tube drainage during the first 12 postoperative hours was significantly less in the IP group (p = 0.022), but no difference was noted in total postoperative blood loss between the two groups. The amount of packed red cells and fresh frozen plasma transfused to the IP group in the intensive care unit was significantly lower (p = 0.02, p = 0.002, respectively); 51.4% of patients required no transfusion compared with the control group (34.5%) (p = 0.006). No differences were noted for data collected in the intensive care unit in terms of the mean duration of chest tube drainage, ventilator time, or any hematologic variables at baseline or at any subsequent time in the study. CONCLUSIONS: After cardiac surgery, intraoperative plasma-pheresis reduces early postoperative bleeding and decreases the need for homologous transfusions.

Blood Loss, Surgical↗
PubMed1996

Regional cerebral blood flow (rCBF) in migraine during the interictal period: different rCBF patterns in patients with and without aura.

The aim of this study was to evaluate the rCBF (133Xe clearance method) in migrainous patients free from attack. Fifty patients suffering from migraine without aura (group M) and 20 suffering from migraine with aura (group MA) (age range 20-50 years) were submitted to 32 channel rCBF mapping during the interictal period. The rCBF data of patients were compared with those obtained from 60 healthy control subjects (group C) and 21 patients suffering from tension-type headache (group TH). The mean (average of all channels) rCBF values were: group M = 70.5 +/- 13.7 ml/100g/min; group MA = 56.6 +/- 11.4 ml/100g/min; group C = 62.3 +/- 8.3 ml/100g/min; group TH = 62.1 +/- 8.4 ml/100g/min (F = 11.93; p < 0.001). As expected, patients belonging to group TH had a normal rCBF. The mean rCBF of group M was significantly higher than that of groups C and TH, while in group MA it was significantly lower than in groups C and TH. Group M showed a diffuse hyperemia, while group MA showed rCBF values significantly lower than normal in posterior regions, according to aura. Our results suggest that: (a) the rCBF pattern in migrainous patients is different from that in both controls and TH patients, even during the interictal period; (b) patients suffering from migraine with and without aura are two distinct subpopulations with opposite rCBF deviations.

Adult↗
PubMed1992

The Post-anaesthetic Recovery in Obesity Surgery: comparison between two anaesthetic techniques.

Forty morbidly obese patients, scheduled for restrictive gastric surgery, were anaesthetized with two different techniques. In group A (20 patients) anesthesia was induced and maintained with Propofol (total intravenous anesthesia, TIVA); in group B (20 patients) anesthesia was induced with Thiopental and maintained with Isoflurane (balanced anesthesia). At the end of surgery, recovery time (RT) and recovery score (RS) were assessed according to a modified Aldrete score. There was no difference of RS between group A and group B. RT was shorter (though not statistically significant) in group A than in group B. Our experience suggests that both techniques can be safely used in these patients, but with TIVA, patients appeared more awake and cooperative earlier. Such an advantage may be useful to prevent serious complications (thromboembolism and pulmonary failure) in the postoperative period.

Journal Article↗
PubMed1991

Spatial mapping of SEP in comatose patients: improved outcome prediction by combined parietal N20 and frontal N30 analysis.

The aim of this study is to evaluate whether SEP spatial mapping can improve outcome prediction in comparison to the conventional SEP recordings. Twenty patients comatose as a result of head injury or cerebral vascular disorders were submitted to 19-channel SEP mapping from median nerve stimulation. SEP recording were performed within the 4th hospital day in 18 cases and over one month from the insult in the remaining two. Nine patients (45%) showed a good recovery or a mild disability, 3 (15%) a severe disability and the rest (40%) died or remained in a vegetative state. Five patients (28%) had bilaterally normal SEP, 5 (28%) the absence of both parietal N20 and frontal N30, while the others (44%) had a dissociation N20/N30 (namely, preserved N20 with absent N30). The SEP mapping was significantly related to the outcome (P = 0.0087) and improved the outcome prediction in comparison to the conventional SEP recordings, allowing to check the presence of frontal N30: in patients with bilaterally present N20 the outcome appeared to depend upon the N30. SEP mapping proved to be a far superior prognostic indicator than the Glasgow Coma Scale. In 3 patients with midline shift on CT scan an abnormal spatial distribution of N20 was disclosed by SEP mapping. Our preliminary results suggest that SEP mapping may improve the assessment of comatose patients in comparison to the use of parietal derivations only.

Adolescent↗
PubMed1990

Value of transesophageal echocardiography during repair of congenital heart defects.

Two-dimensional transesophageal color Doppler echocardiography was employed intraoperatively in 30 children undergoing repair of a variety of simple and complex cardiac malformations. There were 16 female and 14 male patients, with a mean age of 9 +/- 3 years (range, 4 to 13 years) and a mean weight of 31 +/- 9 kg (range, 16 to 50 kg), 16 children weighing less than 30 kg. A standard, commercially available transesophageal echocardiography probe (5 MHz, 64 elements) was used in all patients without complications. Transesophageal echocardiography proved helpful in selecting the surgical approach, in assessing the adequacy of surgical repair, in detecting residual intracardiac shunts, and in allowing uninterrupted monitoring of ventricular performance throughout the procedure. Our initial experience suggests that transesophageal echocardiography is a valuable tool to be used in children with congenital cardiac malformations, particularly in those requiring complex intracardiac procedures. The amount of information obtained by the surgeon should favor the routine use of transesophageal echocardiography during open heart procedures and stimulate the development of probes to be safely used even in infants and newborns.

Child↗
PubMed1988

Serial recordings of auditory brainstem responses in severe head injury: relationship between test timing and prognostic power.

ABRs have proved to be very accurate prognostic indicators in severe head injury, even when predictions are based on single ABR recordings. In this study we submitted 30 severely head-injured patients to serial ABR recordings (during the clinical course of posttraumatic coma) in order to verify whether the ABR prognostic power may depend on test timing in relation to the injury. 15 patients (50%) died, 5 (16.7%) remained vegetative, 2 (6.6%) severely disabled and 8 (26.7%) recovered. All recovered patients had normal ABR throughout clinical course, while severely disabled and vegetative patients showed at least transently ABR abnormalities (namely, an interpeak latency of waves V-I greater than 4.48 ms). Among dead patients, 8 showed steady and 3 transient ABR abnormalities during the clinical course, while 2 of 3 patients with normal ABR dead from extracranial complications. ABRs were significantly related to the outcome at any time, but gave more accurate prognostic indications on days 3-6 after the injury. The use of serial ABR recordings appeared to improve the outcome predictions in comparison with single ABR tests. Finally our result confirm the previously reported existance of a breakpoint between reversible brainstem dysfunction and irreversible brainstem damage defined by an IPL V-I of about 4.50 ms.

Adolescent↗
PubMed1986

L-carnitine effect on halothane-treated mitochondria.

Addition of halothane to the incubation medium is shown to lower respiratory control and transmembrane potential and to increase ATPase activity in isolated rat liver mitochondria. Evidence is presented that L-carnitine is able to substantially decrease the negative effects of halothane on the energy-linked processes of mitochondria. The effects of halothane and the protective action of L-carnitine are discussed in the light of a possible involvement of long-chain acyl CoA in the unpairing of mitochondrial energy-linked functions.

Acyl Coenzyme A↗
PubMed1986

Effects of isoflurane anesthesia on local cerebral glucose utilization in the rat.

The effect of isoflurane anesthesia on local rate of glucose utilization was investigated in the rat brain by means of the autoradiographic 14C-2-deoxyglucose method. Local cerebral glucose utilization (LCGU) was measured in 26 neuroanatomic structures of awake and isoflurane-anesthetized rats. Isoflurane anesthesia (1.5% inspired) caused both increases and decreases in LCGU. Significant reductions were found in all cortical areas examined and in primary sensory relay nuclei of central visual and auditory pathways. Among regions of the extrapyramidal motor system, LCGU was increased in substantia nigra pars compacta, and decreased in cerebellum, red nucleus, and ventral thalamus. Large increases in LCGU were observed in some structures of the limbic system such as the medial habenulo-interpeduncular system and the CA3 field of hippocampus. LCGU was significantly reduced by isoflurane in the CA1-CA2 field and dentate gyrus of hippocampus. These results are similar to previous findings on the LCGU response to other inhaled and intravenous anesthetics and further confirm the regional specificity of the effects of anesthetics on brain metabolism.

Anesthesia, Inhalation↗
PubMed1984

Hemodynamic effects of continuous positive-pressure ventilation and high-frequency jet ventilation with positive end-expiratory pressure in normal dogs.

The hemodynamic effects of high-frequency jet ventilation (HFJV) at 60, 120, 240, and 480 breath/min, and conventional ventilation at 15 breath/min were compared in 6 anesthetized, paralyzed dogs, at 0, 10, and 20 cm H2O of positive end-expiratory pressure (PEEP). On HFJV at the same inspired oxygen, PaCO2, and PEEP levels, hemodynamic function improved significantly. Cardiac output was higher, whereas transmural CVP and pulmonary vascular resistances were lower. The improvement was primarily related to a decrease in mean airway pressure, particularly at higher PEEP levels. When PEEP was applied, hemodynamic function improved even when mean airway pressure was maintained constant. The findings suggest that lung volume was smaller during HFJV, and/or that lung volume changes during each respiratory cycle contributed to differences in venous return and ventricular function.

Animals↗
PubMed1983

Percutaneous glossopharyngeal thermocoagulation complicated by syncope and seizures.

We describe the case of a patient who, during the percutaneous thermocoagulation of the petrous ganglion of Andersch, suffered a serious vagal response resulting in cardiac arrest, collapse, and generalized convulsions. Notwithstanding such major symptoms, the postoperative examination revealed no lesions of the vagus nerve and the glossopharyngeal lesion was shown to be isolated and selective.

Adult↗