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Biomedical subjects

C Meistelman

Publications and source records attributed to C Meistelman.

At least 19 recordsLinked to original sources
PubMed2006

Sequential measurements of troponin Ic values in brain-dead patients considered as potential heart donors.

It was suggested that a single value of normal or increased plasma cardiac troponin T or I (cTnT or cTnI) concentration could contribute to estimate donor myocardial damage and function in brain-dead patients. In patients with acute coronary syndromes, an initial normal value of troponin must be confirmed several hours later but no such recommendations exist for brain-dead patients. We investigated the relationship between two sequential (6 h interval) measurements of plasma cTnI concentrations in brain-dead patients considered as potential heart donors. The first and the second TnIc values were correlated with an adjusted r2 value of 0.92 (p<0.001). Our results suggest therefore that it is not necessary to repeat the measurements, when the value of plasma cTnI concentration is taken into consideration in the algorithm for cardiac harvesting.

Biomarkers↗
PubMed2006

[Renal angiomyolipoma rupture during pregnancy].

A 40 year-old 2nd gesta pregnant woman (34.5 weeks of amenorhea) was admitted to hospital for abdominal pain and arterial hypotension which were rapidly related to a retroperitoneal haematoma due to left kidney bleeding. Emergency cesarean delivery under general anaesthesia was undertaken because of foetal distress. Exploration of the retroperitonal space after foetal extraction confirmed the presence of a large haematoma and abnormal left renal morphology. The retroperitoneal space was drained without any further intervention. Subsequently, abdominal and thoracic computerised tomographic examination showed bilateral dysplasia of the kidneys and pulmonary cysts consistent with the diagnosis of renal angiomyolipoma and pulmonary lymphangioleiomyomatosis. The case report is of interest because of the circumstances of discovery of the disease and because nephrectomy was not necessary to control the bleeding of the left kidney. Six months after the incident the patient and the child are in good condition.

Adult↗
PubMed2006

Inter-patient variability upon induction with sevoflurane estimated by the time to reach predefined end-points of depth of anaesthesia.

BACKGROUND AND OBJECTIVES: A difficult issue in anaesthesia is its titration for an individual patient to avoid over- and underdosage. Common practice is to use an initial dose and increase it subsequently if the defined end-point is not reached. This assumes that the end-point is reached after a similar interval of time in all patients given a similar dose. In order to test this hypothesis we measured the time to reach end-points such as loss of consciousness (LOC), a bispectral index (BIS) value of 60, the minimal BIS and the minimal mean arterial pressure (MAP) values. METHODS: Thirty patients aged 18-60 yr scheduled for general surgery were included in this observational study. After preoxygenation, induction was performed with 6% inspired concentration of sevoflurane in 6 Lmin-1 oxygen using the SiBI connector and the tidal volume technique. Remifentanil was administered when the BIS value was 60 and tracheal intubation was performed 4 min later. RESULTS: Time (median, minimum-maximum) to LOC, a BIS value of 60, the minimal BIS and MAP values were, respectively, 75 (45-135), 120 (75-270), 300 (120-720) and 450 (120-1200) seconds. The time to the minimal BIS value was significantly (P < 0.05) shorter than the time to reach the minimal MAP value. CONCLUSIONS: These results demonstrate large inter-patient variability for the time necessary to reach defined end-points of depth of anaesthesia when a similar dose of anaesthetic is given. Measuring the time to reach a predefined BIS value would allow application of nociceptive stimuli only at adequate levels of hypnosis and would facilitate titration.

Adolescent↗
PubMed2005

[Influence of pregnancy on renal angiomyolipoma].

The aim is to perform a literature search on the role of pregnancy in the rupture of renal angiomyolipoma. Articles published from 1952 to 2004 in the Medline database were searched using the keywords renal angiomylipoma and pregnancy. Pathologies associated with angiomylipoma (lymphangioleiomyomatosis and Bourneville tuberous sclerosis) were taken into account. Seventy-two cases of association of renal angiomyolipoma and pregnancy were found, out of which 58 presented a haemorrhage. In only 26% of the cases, renal angiomyolipoma had been documented prior to pregnancy. Clinical presentation was similar to cases occurring among non pregnant women: abdominal pains (88%), hypotension or shock (33%) and hematuria (24%). Average size of the rupture was 11,7 cm. Rupture does not occur solely with the first pregnancy but occurred equally during the first, second and third pregnancy. Average gestation age upon occurrence of haemorrhage was 27 weeks with a minimum at ten weeks. Therapeutic strategies at the time of shock or hypotension were total nephrectomy in 79% of the cases, 7% polar nephrectomy, 7% embolisation followed by nephrectomy and 7% abstention. A causal role of pregnancy in the atraumatic rupture of angiomyolipoma is not clearly defined. Nevertheless, many arguments (whether it be abdominal mechanical pressure, hormonal or histological ones) suggest that a pregnancy could increase the risk of renal angiomyolipoma rupture. These patients should have a medical follow-up period at closer intervals during their pregnancy and the postpartum phase.

Abdominal Pain↗
PubMed2005

Telerobotic-assisted laparoscopic hysterectomy for benign and oncologic pathologies: initial clinical experience with 30 patients.

BACKGROUND: Telerobotic-assisted laparoscopic attempts to provide technological solutions to the inherent limitations of traditional laparoscopic surgery. The aim of this study is to report the first experience of two teams concerning telerobotic-assisted laparoscopic hysterectomy for benign and malignant pathologies. METHODS: This study included 14 patients at the University Hospital Saint Pierre of Brussels (Belgium) and 16 patients at the Cancer Center of Nancy (France) from September 1999 to July 2003. RESULTS: The indications for surgery were uterine malignant diseases in 12 cases (stade I) (41%), and benign pathologies of the uterus in 18 cases (59%). Five postoperative complications (17%) occurred, none related to the robotic system. CONCLUSION: Robotic surgery can be safely performed in gynecologic and gynecologic-oncologic surgery with no increase in complication rates. A significant advance is represented by the surgeon's ergonomic improvement.

Adult↗
PubMed2004

[Peri-operative anticoagulation with danaparoid for a patient with Budd-Chiari syndrome and heparin-induced thrombocytopenia].

We report a case of Budd-Chiari syndrome revealing a polycythemia vera and complicated by heparin-induced thrombocytopenia. A surgical porto-caval shunt was inserted with danaparoid as anticoagulant during the peri-operative period. The doses of danaparoid were as follows: a continuous intravenous infusion of 200 U/h with a target between 0.5 et 0.8 U/ml antifactor Xa activity during the preoperative period, followed by 100 U/h with a target of 0.3 U/ml during the peroperative period; an increase in doses of danaparoid to 150 and 200 U/h with a target above 0.5 U/ml was used during the postoperative period. This case report is a rare situation of hypercoagulable state, in a surgical context, treated with danaparoid.

Adult↗
PubMed2003

[Analysis of the criteria that contribute to the decision to harvest the heart in brain-dead organ donors].

OBJECTIVES: The number of cardiac transplantation procedures does not increase because of the lack of donor hearts despite an increase in the number of brain-dead organ donors. The criteria used to select a donor heart are not formally standardized. The aim of the present study was to analyze the criteria that contribute to the selection of a donor heart. TYPE OF STUDY: Descriptive, retrospective study. PATIENTS AND METHOD: Clinical parameters, the initial causes that lead to brain death, maximum doses of catecholamines, several biochemical markers of myocardial ischaemia/necrosis as well as several echocardiography criteria were extracted from a prospectively collected database. Univariate and multivariate (logistic regression) analyses were performed with the "harvested heart" as dependent variable and the above-cited independent variables. RESULTS: One hundred and eighty consecutive brain-dead patients admitted from 1st October 1998 to 31st December 2000 out of which 112 gave at least one organ were analyzed. Among these 112 patients, 59 (39 males and 20 females) were pre-selected as potential heart donors. Only 44 hearts were harvested. Logistic regression analysis showed that harvesting of the heart was more probable if the donor were a male, had no left ventricle systolic wall motion abnormalities, had low doses of norepinephrine and low serum troponin Ic concentrations. CONCLUSION: After an initial phase of selection, the final decision to harvest a heart is based on several criteria. These results should be an incentive to conceive a score that could allow a more formal decision process for heart harvesting.

Adolescent↗
PubMed2001

Lipopolysaccharide-induced increase of prostaglandin E(2) is mediated by inducible nitric oxide synthase activation of the constitutive cyclooxygenase and induction of membrane-associated prostaglandin E synthase.

NO produced by the inducible NO synthase (NOS2) and prostanoids generated by the cyclooxygenase (COX) isoforms and terminal prostanoid synthases are major components of the host innate immune and inflammatory response. Evidence exists that pharmacological manipulation of one pathway could result in cross-modulation of the other, but the sense, amplitude, and relevance of these interactions are controversial, especially in vivo. Administration of 6 mg/kg LPS to rats i.p. resulted 6 h later in induction of NOS2 and the membrane-associated PGE synthase (mPGES) expression, and decreased constitutive COX (COX-1) expression. Low level inducible COX (COX-2) mRNA with absent COX-2 protein expression was observed. The NOS2 inhibitor aminoguanidine (50 and 100 mg/kg i.p.) dose dependently decreased both NO and prostanoid production. The LPS-induced increase in PGE(2) concentration was mediated by NOS2-derived NO-dependent activation of COX-1 pathway and by induction of mPGES. Despite absent COX-2 protein, SC-236, a putative COX-2-specific inhibitor, decreased mPGES RNA expression and PGE(2) concentration. Ketoprofen, a nonspecific COX inhibitor, and SC-236 had no effect on the NOS2 pathway. Our results suggest that in a model of systemic inflammation characterized by the absence of COX-2 protein expression, NOS2-derived NO activates COX-1 pathway, and inhibitors of COX isoforms have no effect on NOS2 or NOS3 (endothelial NOS) pathways. These results could explain, at least in part, the deleterious effects of NOS2 inhibitors in some experimental and clinical settings, and could imply that there is a major conceptual limitation to the use of NOS2 inhibitors during systemic inflammation.

Animals↗
PubMed2001

Retinoic acid attenuates inducible nitric oxide synthase (NOS2) activation in cultured rat cardiac myocytes and microvascular endothelial cells.

S. Grosjean, Y. Devaux, C. Seguin, C. Meistelman, F. Zannad, P.-M. Mertes, R. A. Kelly and D. Ungureanu-Longrois. Retinoic Acid Attenuates Inducible Nitric Oxide Synthase (NOS2) Activation in Cultured Rat Cardiac Myocytes and Microvascular Endothelial Cells. Journal of Molecular and Cellular Cardiology (2001) 33, 933-945. The inducible NO synthase (NOS2) in cardiac tissue contributes to myocardial and coronary inflammation and dysfunction. Several natural (endogenous) hormones such as retinoic acid, the active metabolite of vitamin A, have the ability to attenuate NOS2 activation in inflammatory cells. The aim of this study was to investigate the effect of RA on NOS2 activation in cultured cardiac microvascular endothelial cells (CMEC) and adult rat ventricular myocytes (ARVM). CMEC were stimulated either with a combination of 10 microg/ml lipopolysaccharide (LPS) and 50 IU/ml interferon- gamma (IFN- gamma) or with a combination of 1 ng/ml interleukin-1 beta (IL-1 beta)+IFN- gamma whereas ARVM were stimulated with 1 ng/ml IL-1 beta and 50 IU/ml IFN- gamma in the absence or presence of all-trans retinoic acid (atRA). Activation of the NOS2 pathway was estimated by measurement of mRNA (Northern blot) and protein (Western blot) expression, enzyme activity by conversion of [(3)H]L -arginine to [(3)H]L -citrulline, and nitrite accumulation. NOS2 mRNA half-life was studied in CMEC and ARVM in the presence of actinomycin D. In CMEC and ARVM stimulated with a combination of LPS and/or cytokines, atRA (10(-6), 10(-5)M) significantly (P<0.05) attenuated NOS2 mRNA and protein expression, enzymatic activity and reduced supernatant nitrite concentration. Upon stimulation with LPS/IFN- gamma, atRA significantly decreased NOS2 mRNA half-life. This was not seen after stimulation with IL-1 beta/IFN- gamma. These results document for the first time an effect of RA on NOS2 activation in cardiac cells. They may contribute to the characterization of the immunomodulatory effects of retinoids in myocardial and coronary inflammatory disorders.

Animals↗
PubMed2001

Life-threatening pneumothorax of the ventilated lung during thoracoscopic pleurectomy.

PURPOSE: To report the case of a patient who underwent right thoracoscopic pleurectomy with lung exclusion and developed contralateral (left) pneumothorax with resulting life-threatening alteration of the respiratory and cardiovascular functions. CLINICAL FEATURES: A 28-yr-old male was admitted to the intensive care unit for a well tolerated, second episode of spontaneous right pneumothorax and scheduled for right thoracoscopic pleurectomy. Anesthesia was induced and maintained with sufentanil and propofol. A double lumen endotracheal tube (ETT) was inserted, its correct positioning checked clinically and by fiberoptic bronchoscopy and the patient was placed in the left decubitus position. Approximately one hour into the procedure, during the second period of right pulmonary exclusion, SpO2 values decreased within two minutes to 78%. End tidal capnography (EtCO2) values decreased to 6-8 mmHg within seconds and peak airway pressure increased to values between 50 and 60 cm H2O. Severe cyanosis, sinus bradycardia and arterial hypotension developed. The surgical procedure was stopped, propofol administration discontinued, bipulmonary ventilation reinstituted and the patient placed in the supine position which restored hemodynamic and respiratory function. Inspection and auscultation were consistent with tension left pneumothorax which was evacuated. CONCLUSION: Pneumothorax of the ventilated lung during one lung ventilation for thoracoscopic procedures must be diagnosed quickly. Reinstitution of bipulmonary ventilation should probably be the first therapeutic attitude.

Adult↗
PubMed2001

Retinoic acid and lipopolysaccharide act synergistically to increase prostanoid concentrations in rats in vivo.

Vitamin A and its active metabolite retinoic acid (RA) modulate host-pathogen interactions by interfering with the host immune and inflammatory response including prostaglandin (PG) biosynthesis. The effects of RA on phospholipase A(2) (PLA(2)) and cyclooxygenase (COX) isoforms in vitro are controversial, and few in vivo studies exist. We investigated the in vivo effects of RA on PG biosynthesis in the presence or absence of lipopolysaccharide (LPS) in rats. RA alone [10 mg/(kg. d) for 5 d] increased plasma and liver PG concentrations by increasing COX-1 protein expression (twofold that of control rats). RA acted synergistically with LPS to increase plasma (400-fold) and liver (15-fold) concentrations of prostaglandin E(2) (PGE(2)) and significantly, but to a lesser extent, other PG compared with RA rats, in the absence of major differences in PLA(2) expression or activity or COX-1 and COX-2 mRNA or protein expression. The RA + LPS-mediated increase in PGE(2) was significantly attenuated (97%) by aminoguanidine (AG), a relatively specific inhibitor of the inducible nitric oxide synthase (NOS2), consistent with the previously reported synergistic effect of RA and LPS on NOS2 expression and activity. In addition, RA and LPS induced the expression of the microsomal isoform of PGE synthase (mPGES). In conclusion, in vivo, RA and LPS increased PG and especially PGE(2) concentrations. The PGE(2) increase was associated with NOS2-mediated activation of COX and induction of mPGES. These results contribute to the characterization of the effects of vitamin A on the host inflammatory response.

Animals↗
PubMed2001

Update on neuromuscular pharmacology.

Since the introduction of d-tubocurarine into clinical practice, neuromuscular relaxants have been widely used in anaesthesia. Although their clinical use is easy, several points still require further attention and research. There is still a need for a drug with the clinical profile of succinylcholine but fewer unwanted side-effects. A better understanding of the effects of muscle relaxants on different muscles could help in their clinical use during the perioperative period. Much knowledge is needed about residual neuromuscular block and its detection in order to improve the quality of recovery from neuromuscular blockade. If some questions remain to be answered, several recent articles have increased our knowledge and should improve our clinical practice.

Journal Article↗
PubMed2000

Recombinant hirudin anticoagulation for aortic valve replacement in heparin-induced thrombocytopenia.

PURPOSE: To report the case of a patient with HIT that received a prolonged infusion of r-hirudin (lepirudin; Refludan; Hoechst, France) before, during and after cardiopulmonary bypass (CPB) for aortic surgery. Although administration of r-hirudin for CPB anticoagulation has previously been reported, many questions persist concerning the best therapeutic regimen for CPB anticoagulation as well as the time of onset and the doses for postoperative anticoagulation. CLINICAL FEATURES: A 65-yr-old man was admitted for surgery of aortic stenosis after an episode of acute pulmonary edema complicated by deep venous thrombosis in the context of documented HIT. The patient received r-hirudin for 13 dy before surgery at doses (0.4 mg x kg(-1) bolus followed by 0.15 mg x kg(-1) x hr(-1) continuous infusion) that maintained activated partial thromboplastin time (aPTT) ratios between 2 and 2.5. Anticoagulation for CPB was performed with r-hirudin given as 0.1 mg x kg(-1) i.v. bolus and 0.2 mg kg(-1) in the CPB priming volume. Anticoagulation during CPB was monitored with the whole blood activated coagulation time and ecarin clotting time (ECT) performed in the operating room with values corresponding to r-hirudin concentrations >5 microg x ml(-1) during CPB. Anticoagulation during CPB was uneventful. Two bleeding episodes, related to the r-hirudin regimen and necessitating allogeneic blood transfusion, occurred after surgery. CONCLUSION: This case report confirms previous experience of the use of r-hirudin for anticoagulation during CPB and provides additional information in the context of prolonged r-hirudin infusion before and after CPB.

Aged↗
PubMed2000

Effects of normothermic cardiopulmonary bypass on bispectral index.

This study investigated the changes in the hypnotic component of anaesthesia, estimated by the bispectral index of the electroencephalogram, during normothermic cardiopulmonary bypass. Twenty-six patients (20 men, 6 women), aged 61 +/- 11 years (Mean +/- SD) scheduled for cardiac surgery were premedicated with hydroxyzine and meperidine. Anaesthesia was induced and maintained with a computer-controlled continuous infusion (not adjusted for haemodilution) of sufentanil (effect site concentration 0.4-0.6 ng mL-1) and a manually adjusted continuous infusion of propofol (4.4 +/- 1.8 mg kg-1 h-1). Cardiopulmonary bypass was normothermic with moderate haemodilution. Bispectral index was measured with a referential montage before, 30 s, 1, and 3 min after cardiopulmonary bypass onset, before and after aortic cross-clamping, 30 min after cardiopulmonary bypass onset, before and after aorta cross-clamp release and before and after weaning from cardiopulmonary bypass. Bispectral index values were 48 +/- 8 before cardiopulmonary bypass onset, 50 +/- 10 before, and 48 +/- 8 after end of cardiopulmonary bypass (P = NS). No patient had increases in bispectral index values during cardiopulmonary bypass consistent with awakening. We conclude that with the anaesthetic regimen presented in this study bispectral index values do not change during normothermic cardiopulmonary bypass.

Adjuvants, Anesthesia↗
PubMed2000

Retinoic acid and host-pathogen interactions: effects on inducible nitric oxide synthase in vivo.

Vitamin A and its metabolite retinoic acid modulate the host response to pathogens through poorly characterized mechanisms. In vitro studies have suggested that retinoic acid decreases inducible NO synthase (NOS2, or iNOS) expression, a component of innate immunity, in several cell types stimulated with lipopolysaccharide (LPS) or cytokines. This study investigated the effect of retinoic acid on LPS-stimulated NOS2 expression in vivo. Wistar-Kyoto rats received all-trans retinoic acid (RA, 10 mg/kg) or vehicle intraperitoneally daily for 5 days followed by LPS (4 mg/kg) or saline intraperitoneally and were killed 6 h later. NOS2 activation was estimated by mRNA (RT-PCR) and protein (Western-blot) expression and plasma nitrate/nitrite accumulation. In sharp contrast to previous in vitro study reports, RA significantly enhanced NOS2 mRNA, protein expression, and plasma nitrate/nitrite concentration in LPS-injected rats but not in saline-injected rats. This was associated with increased expression of interleukin-2, interferon (IFN)-gamma and IFN regulatory factor-1 mRNAs in several organs and increased IFN-gamma plasma concentration. RA significantly increased mortality in LPS-injected rats. The NOS inhibitor aminoguanidine (50 mg/kg before LPS injection) significantly attenuated the RA-mediated increase in mortality. These results demonstrate for the first time that RA supplementation in vivo enhances activation of the LPS-triggered NOS2 pathway.

Animals↗