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Biomedical subjects

B Palmier

Publications and source records attributed to B Palmier.

At least 19 recordsLinked to original sources

Prospective randomized comparison of progressive dilational vs forceps dilational percutaneous tracheostomy.

This trial prospectively compares two methods of percutaneous tracheostomy, both routinely used in ICU: the Ciaglia progressive dilational tracheostomy and the Griggs forceps dilational tracheostomy. One hundred patients were randomized using a single-blinded envelope method to receive progressive or forceps percutaneous tracheostomy performed at the bedside. Operative time, the occurrence of hypoxaemia or hypercapnia and complications were recorded. The progressive technique took longer than the forceps technique (median 7 (range 2-26) vs. 4 (1-16) minutes, P = 0.0005). Hypercapnia occurred in both groups but was more marked with the progressive technique (56 (16) vs. 49 (13) mmHg, P = 0.0082). Minor complications (minor bleeding, transient hypoxaemia, damage to posterior tracheal wall without emphysema) were also more frequent with the progressive technique (31 vs. 9 complications, P < 0.0001). Six major complications occurred with the progressive technique, none with the forceps technique (P = 0.0085): tension pneumothorax, posterior tracheal wall injury with subcutaneous emphysema, loss of airway with hypoxaemia, loss of stoma with impossible re-catheterization, and two conversions to another technique. In conclusion, progressive dilational tracheostomy took longer, caused more hypercapnia and more minor and major difficulties than forceps dilational tracheostomy.

Adult↗

Selective inhibition of inducible nitric oxide synthase reduces neurological deficit but not cerebral edema following traumatic brain injury.

The role of inducible nitric oxide synthase (iNOS) in cerebral edema and neurological deficit following traumatic brain injury (TBI) is not yet clear-cut. Therefore, the aim of this study was to investigate the effect of three different iNOS inhibitors on cerebral edema and functional outcome after TBI. First, the time courses of blood--brain barrier (BBB) breakdown, cerebral edema, and neurological deficit were studied in a rat model of fluid percussion-induced TBI. The permeability of BBB to Evans blue was increased from 1 h to 24 h after TBI. Consistently, a significant increase in brain water content (BWC) was observed at 6 and 24 h post-TBI. A deficit in sensorimotor neurological functions was also observed from 6 h to 7 days with a maximum 24 h after TBI. Second, a single dose of aminoguanidine (AG; 100 mg/kg, i.p.), L-N-iminoethyl-lysine (L-NIL; 20 mg/kg, i.p.), or N-[3-(aminomethyl)benzyl]acetamide (1400W; 20 mg/kg, s.c.) was administered at 6 h post-TBI. Treatment with AG reduced by 71% the increase in BWC evaluated at 24 h, while L-NIL and 1400W had no effect. In contrast, the three iNOS inhibitors reduced the neurological deficit from 30% to 40%. Third, 1400W (20 mg/kg, s.c.) was administered at 5 min, 8 and 16 h post-TBI. Although this treatment paradigm had no effect on cerebral edema evaluated at 24 h, it significantly reduced the neurological deficit and iNOS activity. In conclusion, iNOS contributes to post-TBI neurological deficit but not to cerebral edema. The beneficial effect of iNOS inhibitors is not due to their anti-edematous effect, and the reduction of cerebral edema by AG is unlikely related to iNOS inhibition. The 6 h therapeutic window of iNOS inhibitors could allow their use in the treatment of functional deficit at the acute phase of TBI.

Amidines↗

[A sudden C3-C4 tetraplegia revealing an intracranial dural arteriovenous draining into the spinal medullary veins].

We report a case of intracranial dural arteriovenous (DAVF) draining into the spinal medullary veins. A 49-year-old woman presented a rapidly progressive ascending myelopathy resulting in a C3-C4 tetraplegia associated with acute respiratory failure at the twelfth hour. MRI revealed swelling of the cervical spinal cord, hyperintensity on T2 and enhancement of enlarged veins on MR angiography. A conventional angiography showed the DAVF with venous drainage into the spinal vein extending to the conus medullaris. After embolization, neurological recovery occurred during the first week, allowing tracheal extubation on day 2. Clinical, radiological and therapeutic aspects of this uncommon pathology are presented.

Arteriovenous Anastomosis↗

[Isolated acquired factor VII deficiency in patient with severe head trauma: use of factor VII (factor VII-LFB].

We report a case of transient acquired and isolated factor VII deficiency associated with severe head trauma. A 16-year-old boy was involved in a motor vehicle accident. CT scan showed frontal brain contusion and a cerebral haematoma (5 cm). First prothrombine time (PT) was normal. Rapidly, a severe coagulopathy developed, unresponsiving to fresh frozen plasma and vitamin K. Haemostatic markers analysis showed an isolated deficiency of factor VII at 15%. No inhibitory activity against factor VII could be detected. We successfully treated the deficiency with intermittent intravenous human factor VII (factor VII-LFB) during 10 days. Factor VII return to normal at 84%. Physiopathological and therapeutic aspects of this rare pathology are presented.

Accidents, Traffic↗

Nitric oxide inhalation is useful in the management of right ventricular failure caused by myocardial contusion.

We report a severe head injury and blunt chest trauma with sternal and multiple rib fractures with high-energy impact in a 22-year-old man. Twelve hours after the accident, haemodynamic status of the patient rapidly worsened because of right ventricular (RV) failure due to myocardial contusion, requiring increasing doses of catecholamine. Nitric oxide inhalation was used to decrease RV afterload, and produced an immediate improvement in haemodynamic status, permitting a decrease in catecholamine administration. From days 2 through 8, cardiac function continued to improve, and was normal on day 9. Nitric oxide inhalation was stopped on day 4.

Accidents, Traffic↗

Pattern of cerebral edema and hemorrhage in a mice model of diffuse brain injury.

This study aims to examine the time course of the brain edema formation in relation with blood-brain barrier (BBB) disruption and cerebral hemorrhage in a murine model of diffuse brain injury. Brain water content increased at 1 h post-injury and persisted up to 7 days. This event was associated with electrolyte imbalance such as Na(+) increase within 24 h. Prominent Evans blue extravasation was also observed from 1 to 6 h post-injury. Concurrently, hemoglobin increased markedly by 1 h, reached a peak at 4 h and declined progressively within a week in association with a rise of parenchyma iron content between 24 h and 7 days. These results suggest that brain edema is vasogenic and that the hemorrhage process is involved in the BBB disruption and edema, both leading to post-traumatic secondary events.

Animals↗

[Auditive and somato-sensory event-related potentials in comas: prognostic value for awakening, social and professional reinstatement].

OBJECTIVE: To appreciate prognostical value of event-related potentials in comatose states and the influence of the stimulation's modality. PATIENTS AND METHODS: Thirty-five patients were recorded with the auditory modality whose thirteen were also recorded with the somesthetic modality. They were free of sedation except for five. For 21 patients out of coma, it was possible to get information about their social readaptation 14 months later. RESULTS: When present, cognitive components predict awakening in 100 % of the cases, but only 50 % of the patients who awake had these components. The somesthetic modality seemed to enlarge their detection, but did not improve short-term forecasts. We could not confirm their absence could hamper social reinstatement. CONCLUSION: Event-related potentials are strengthened as having excellent positive prognostic value. Further studies should clarify the interest of the somesthetic modality, and the possibility to get remote prognostic.

Adolescent↗

Sufentanil supplementation of sevoflurane during induction of anaesthesia: a randomized study.

BACKGROUND AND OBJECTIVE: The use of opioids with sevoflurane for induction of anaesthesia is associated with fewer reactions to laryngoscopy but increases the risk of apnoea. Thus it is important to search for the optimal opioid dose. The aim of this study was to compare two sufentanil doses during induction with sevoflurane in young adults. METHODS: Sixty-three young patients (18-26 yr) undergoing wisdom-tooth extraction were randomly allocated to one of the two sufentanil dose groups: 0.15 microg kg(-1) (n = 33) or 0.30 microg kg(-1) (n = 30). Sufentanil was injected 1 min before sevoflurane inhalation. Sevoflurane was inhaled using the three-breath vital-capacity technique with 8% sevoflurane and 100% oxygen. The anaesthesiologist decided when to intubate the trachea. The length of time for intubation was measured. In addition, any apnoea, patient movement, adequacy of the laryngoscopic view, coughing and haemodynamic responses were recorded. RESULTS: Mean time to intubate the trachea, full laryngoscopy view and open-cord position were similar in both groups. The incidence of apnoea was higher in Group 0.30 (P < 0.05). The incidence of patient movement (P < 0.05) and coughing (P < 0.001) was lower in Group 0.30 than in Group 0.15. Sufentanil 0.30 microg kg(-1) attenuated the change in heart rate more effectively than sufentanil 0.15 microg kg(-1). Mean arterial pressure was similar and stable in both groups during induction of anaesthesia. CONCLUSIONS: In current clinical practice during sevoflurane induction, sufentanil 0.30 microg kg(-1) provided a better quality of induction than sufentanil 0.15 microg kg(-1), without significant cardiovascular depression, although the risk of apnoea is increased.

Adjuvants, Anesthesia↗

Rapid reversal of global left ventricular dysfunction after accidental injection of 0.75 mg epinephrine in a 20-year-old patient.

We report an accidental injection of epinephrine before spinal anaesthesia in a 20-year-old patient who subsequently developed immediate myocardial ischemia and global left ventricular dysfunction (ejection fraction of 20%). Hemodynamic status dramatically improved after nitroglycerin, calcium antagonists, acetyl salicylic acid and unfractionated heparin injections. Over 24 h, patient's ejection fraction fully recovered without kinetic abnormality.

Adult↗

Dermal regeneration template for deep hand burns: clinical utility for both early grafting and reconstructive surgery.

Adequate acute treatment of the deeply burned hand and any subsequent reconstructive procedures may be hampered by the lack of sufficient suitable graft material and the risks of donor site morbidity and scarring. This investigation was designed to determine the feasibility of treating deep hand burns using a dermal regeneration template. Patients with deep hand burns underwent either acute treatment or reconstructive procedures with Integra dermal regeneration template. Wound sites were first grafted with the dermal regeneration template, and then 2-3 weeks later after neodermis formation the silicone layer of the Integra was removed and a very thin split-thickness epidermal autograft placed. Acute grafting was performed on 15 hands in 11 patients and reconstructive surgery on 14 hands in 11 patients. Median follow-up was 12 months. Integra take was 100% on all treated hands. After acute grafting the wound site skin was flexible and supple and did not adhere to the deeper layers, thus permitting free articular and functional movement. Cosmetic results of acute surgery were judged satisfactory by both patients and surgeons. After reconstructive procedures, significant improvements were achieved in cosmetic status, based on Vancouver Scar Scale (p=0.0002), and in three measures of function, namely, thumb opposition score (p=0.0005), fingertip-to-palm distance (p=0.0039) and prehensile score (p=0.0039). Favourable cosmetic and functional outcomes were consistently attained using a synthetic dermal regeneration template for treatment of deep hand burns either by acute grafting or reconstructive surgery.

Adolescent↗

Apoptotic mitochondrial pathway in neurones and astrocytes after neonatal hypoxia-ischaemia in the rat brain.

Neuronal apoptosis plays an essential role in early brain development and contributes to secondary neuronal loss after acute ischaemia. Recent studies have provided evidence that caspase-3 is an important downstream event after hypoxia-ischaemia in the immature brain, but a minor event in the adult brain. Our investigations have focused on cell populations that expressed apoptotic effectors in the enzymatic death pathway including cytochrome c, caspase-9 and caspase-3. Expression, activation and cellular localization of these proteins were studied using cleavage of fluorogenic substrate and immunohistochemistry in neonatal rat brain after unilateral focal ischaemia. Caspase-3 enzyme activity was elevated in brain homogenate between 6 and 48 h after reperfusion. This activation was preceded by that of caspase-9, between 3 and 24 h. Apoptotic cell death was finally accomplished by poly-ADP-ribose polymerase cleavage, an endogenous caspase-3 substrate. In addition, immunodetection demonstrated that cytochrome c and activated caspase-9 and caspase-3 were expressed not only in the neurones, the primarily affected cells, but also within the astrocytes, which constituted a dense network delineating the infarct. These results suggested that glial injury may promote the formation of cystic lesions such as those observed clinically in the newborn brain.

Animals↗

Detrimental role of bradykinin B2 receptor in a murine model of diffuse brain injury.

Inhibition of the bradykinin B2 receptor type (B2R) has been shown to improve neurological outcome in models of focal traumatic brain injury. However, the involvement of B2R in trauma-induced diffuse injury has not yet been explored. This is an important point, since in humans a pattern of diffuse injury is commonly found in severely injured patients and has been associated with a poor neurological outcome and prognosis. Using the non-peptide B2R antagonist LF 16-0687 Ms and B2R null (B2R-/-) mice, we investigated the role of B2R in a model of closed head trauma (CHT). LF 16-0687 Ms given 30 min after injury reduced the neurological deficit by 26% and the cerebral edema by 22% when evaluated 4 h after CHT. Neurological function after CHT was improved in B2R-/- mice compared to B2R+/+ mice, although there was no difference in the development of brain edema. Treatment with LF 16-0687 Ms and B(2)R gene deletion decreased the accumulation of neutrophils at 24 h after CHT (50% and 36%, respectively). In addition, the inducible NO synthase (iNOS) mRNA level increased markedly, and this was reduced by LF 16-0687 Ms. Taken together, these data support a detrimental role of B2R in the development of the neurological deficit and of the inflammatory secondary damage resulting from diffuse traumatic brain injury. Therefore, blockade of bradykinin B2 receptors might represent an attractive therapeutic approach in the pharmacological treatment of traumatic brain injury.

Animals↗

Effects of hypothermic deep-anaesthesia on energy metabolism at brain and peripheral levels: a multi-probe microdialysis study in free-moving rat.

Reduction of central energy metabolism is a strategy to protect brain against neurotoxic events. The aim of this microdialysis study in rats is to evaluate changes in energy metabolite levels at central level (striatum) comparatively to peripheral level (subcutaneous adipose tissue) during hypothermic barbituric deep-anaesthesia (sodium pentobarbital 60 mg/kg intraperitoneally). At brain level, extracellular glucose increases (+14.9%) while lactate decreases (-16.6%); opposite results were observed at subcutaneous level (-29.2% for glucose and +68.3% for lactate). Lactate/pyruvate ratio remains unchanged at brain level, but increases at subcutaneous level (+73.5%). In light of previous studies on the effects of pentobarbital on regional blood flow and tissue glucose consumption, our data correlates the fact that pentobarbital reduces preferentially brain energetic metabolism. We suggest that those regional effects are explained, at least for a part, by the fact that central isoform glucose transporters (Glut1 and Glut3) are known to be more sensitive to pentobarbital than peripheral isoforms. Such facts can be involved in the protection of brain tissue against ischemic risk due to decreased cerebral blood flow decrease.

Adjuvants, Anesthesia↗

[Integra, a new surgical alternative for the treatment of massive burns. Clinical evaluation of acute and reconstructive surgery: 39 cases].

Early excision and prompt coverage in severely burned patients are the best way to lessen morbidity and improve survival. Repair of full-thickness burns requires replacement of both dermal and epidermal components of skin and treatment with split thickness autografts replaces both of them. But healthy skin is not sufficient in extensive burns. Alternative to split thickness skin grafts have been studied by several groups including epidermis, dermis or a complete replacement comprising epidermis and dermis. Because of the difficulties in homografts supplying, a new way was use to replace the dermis. In 1981, Yannas and Burke were the first to develop such a matrix. Intégra is available in France since 1997 and was used in our service for the treatment of both acute and reconstructive surgery for burned patients. Twenty patients were treated for acute surgery. Nineteen patients were treated for reconstructive surgery of burn scar contractures. Fifty-one grafts of Intégra were performed. Long-term final results seem to show that Intégra improve cosmetical and functional results and is a new surgical alternative for the treatment of burns in the acute phase as well as in late surgery of deformities.

Activities of Daily Living↗

[Acute respiratory distress syndrome after prolonged hyperbaric oxygen therapy: a case of pulmonary oxygen toxicity?].

A 42-year-old patient was admitted to our ICU for severe decompression illness with tetraplegia. He presented an acute respiratory distress syndrome (ARDS), following a very long hyperbaric oxygen therapy (using a US. Navy Treatment Table 7). The ARDS resulted in pulmonary fibrosis, and the patient died despite maximal support in ICU. The risk of pulmonary toxicity of oxygen must be considered when using a prolonged recompression treatment table.

Acute Disease↗

Platelet-derived growth factor stimulates phospholipase C-gamma 1, extracellular signal-regulated kinase, and arachidonic acid release in rat myometrial cells: contribution to cyclic 3',5'-adenosine monophosphate production and effect on cell proliferation.

In the present study, we examined downstream signaling events that followed exposure of cultured rat myometrial cells to platelet-derived growth factor (PDGF) and their effect on cell proliferation. PDGF-BB induced tyrosine phosphorylation of PDGF-beta receptors and increased inositol trisphosphate production via the tyrosine phosphorylation of phospholipase (PL)C-gamma 1. PDGF-BB also increased cAMP synthesis. This increase was potentiated by forskolin and reduced by indomethacin, a cyclooxygenase inhibitor, reflecting a Gs protein-mediated process via prostaglandin biosynthesis. The prostaglandin produced by PDGF was characterized as prostacyclin (PGI(2)). PDGF-BB increased arachidonic acid (AA) release, which, similarly to cAMP accumulation, was abolished in the presence of AACOCF3, a cytosolic PLA(2) inhibitor, and in the absence of Ca(2+). U-73122, a potent inhibitor of PLC activity, blocked both the production of inositol phosphates and the AA release triggered by PDGF-BB. Extracellular signal-regulated kinases (ERKs) 1 and 2 are expressed in myometrial cells, and PDGF-BB selectively activated ERK2. PD98059, an inhibitor of the ERK-activating kinase, blocked PDGF-BB-mediated ERK2 activation, AA release, and cAMP production. The results demonstrate that PDGF-BB stimulated cAMP formation through both PLC activation and ERK-dependent AA release and PGI(2) biosynthesis. PDGF-BB also increased cell proliferation and [(3)H]thymidine incorporation. This was abolished by PD98059, demonstrating that the ERK cascade is required for the mitogenic effect of PDGF-BB. Forskolin, which potentiated the cAMP response to PDGF-BB, attenuated both DNA synthesis and ERK activation triggered by PDGF-BB, suggesting the presence of a negative feedback regulation.

1-Methyl-3-isobutylxanthine↗

Bone sialoprotein-induced reparative dentinogenesis in the pulp of rat's molar.

Bone sialoprotein (BSP), an osteogenic protein (OP), mixed with a carrier, was implanted in the pulp of rat first upper molars (OP group). Cavities were prepared with dental burs and pulp perforation was carried out by pressure with the tip of a steel probe. After 8, 14, and 30 days, the rats were killed and the pulps of the OP group were compared with (1) a sham group (S group), (2) a group where the carrier was implanted alone (C group), and (3) capping with calcium hydroxide (Ca group). After 8 days, a few inflammatory cells were seen, mostly located at the pulp surface near the perforation. In the Ca group, a dentin bridge started to form, in contrast to the other groups. After 15 days, globular structures were seen in the pulps of the S and C groups. A reparative osteodentin bridge isolated the pulp from the cavity in the Ca group. Variable reactions were seen in the OP group, with some evidence of cell and matrix alignments or plugs of osteodentin in continuity with an inner layer of reparative dentin. After 30 days, irregular osteodentin formation was observed in the pulps of the S and C groups, with a tendency for globular structures to merge, but with interglobular spaces filled by pulp remnants. In the Ca group, osteodentin was observed in the mesial part of the pulp chamber. In the BSP-implanted group, the osteogenic protein stimulated the formation of a homogeneous dentin-like deposit occupying most of the mesial part of the pulp. Apparently, BSP stimulates the differentiation of cells which secrete an organized extracellular matrix more efficiently than any other capping material used so far. Altogether, the results reported here support that bone sialoprotein displays novel bioactive properties and is capable of stimulating in 1 month's time the development of a thick reparative dentinal tissue in the pulp, occluding the perforation and filling the mesial third of the pulp chamber.

Animals↗