Biomedical subjects

J S David

Publications and source records attributed to J S David.

At least 19 recordsLinked to original sources

PubMed2006

Diagnosis of early coagulation abnormalities in trauma patients by rotation thrombelastography.

BACKGROUND: Reagent-supported thromboelastometry with the rotation thrombelastography (e.g. ROTEM) is a whole blood assay that evaluates the visco-elastic properties during blood clot formation and clot lysis. A hemostatic monitor capable of rapid and accurate detection of clinical coagulopathy within the resuscitation room could improve management of bleeding after trauma. OBJECTIVES: The goals of this study were to establish whether ROTEM correlated with standard coagulation parameters to rapidly detect bleeding disorders and whether it can help to guide transfusion. METHODS: Ninety trauma patients were included in the study. At admission, standard coagulation assays were performed and ROTEM parameters such as clot formation time (CFT) and clot amplitude (CA) were obtained at 15 min (CA(15)) with two activated tests (INTEM, EXTEM) and at 10 min (CA(10)) with a test analyzing specifically the fibrin component of coagulation (FIBTEM). RESULTS: Trauma induced significant modifications of coagulation as assessed by standard assays and ROTEM. A significant correlation was found between prothrombin time (PT) and CA(15)-EXTEM (r = 0.66, P < 0.0001), between activated partial thromboplastin time and CFT-INTEM (r = 0.91, P < 0.0001), between fibrinogen level and CA(10)-FIBTEM (r = 0.85, P < 0.0001), and between platelet count and CA(15)-INTEM (r = 0.57, P < 0.0001). A cutoff value of CA(15)-EXTEM at 32 mm and CA(10)-FIBTEM at 5 mm presented a good sensitivity (87% and 91%) and specificity (100% and 85%) to detect a PT > 1.5 of control value and a fibrinogen less than 1 g L(-1), respectively. CONCLUSIONS: ROTEM is a point-of-care device that rapidly detects systemic changes of in vivo coagulation in trauma patients, and it might be a helpful device in guiding transfusion.

Blood Coagulation Disorders↗

PubMed2005

Is ECG-guidance a helpful method to correctly position a central venous catheter during prehospital emergency care?

BACKGROUND: Insertion of a central venous catheter (CVC) in an emergency situation is challenging and may be potentially associated with more complications. Because CVC positioning by ECG-guidance may help to decrease the frequency of a malpositioned catheter, we decided to prospectively evaluate the usefulness of positioning a CVC by ECG-guidance during prehospital emergency care. METHODS: Prospective observational study during which all patients requiring CVC placement during prehospital care were included. We compared two periods of 1 year during which CVCs were inserted without and then with the help of ECG-guidance. RESULTS: Eighty successive patients were included. We observed a significant reduction of incorrectly positioned CVCs with ECG-guidance (13% vs. 38%, P < 0.05) and a decreased number of chest X-rays needed to verify the position of the CVC (40 vs. 54, P < 0.05). CONCLUSION: ECG-guidance is a safe and feasible technique which significantly improved the rate of CVCs correctly positioned during prehospital emergency care.

Adult↗

PubMed2002

[New aspects and perspectives on cardiac arrest].

OBJECTIVES: To analyse the current knowledge based on the experimental and the clinical research studies focused on the main fields of cardiopulmonary resuscitation. DATA SOURCES: International guidelines and recent review articles. Data collected from the Medline database with the key word: cardiac arrest. STUDY SELECTION: Research studies published during the last ten years were reviewed. Relevant clinical information was extracted and discussed when it induced changes in guidelines. DATA SYNTHESIS: Promising improvements on basic and advanced life supports are proposed. Chest compressions prevail over ventilation. Alternatives to classical chest compressions are tested. Ventilatory volume must be reduced from 1000 to approximatively 500 mL for each breath with oxygen. Biphasic waveform defibrillators and automated external defibrillators will be considered as the best devices in the near future. Some non-catecholaminergic vasopressors could reduce the use of epinephrine for advanced cardiac life support. Lidocaine could be replaced by amiodarone as anti-arrhythmic drug of choice. New post-resuscitation therapeutic strategies are evaluated, especially coronary reperfusion when the cause of cardiac arrest is cardiac. CONCLUSION: Many fields of cardiopulmonary resuscitation are investigated. Some relevant informations are included in the last international guidelines published in 2000, but most of them need complementary studies before other changes could be recommended for routine practice.

Cardiopulmonary Resuscitation↗

PubMed2002

Pharmacological preconditioning: comparison of desflurane, sevoflurane, isoflurane and halothane in rabbit myocardium.

BACKGROUND: Recent investigations showed that isoflurane can induce pharmacological preconditioning. The present study aimed to compare the potency of four different halogenated anaesthetics to induce preconditioning. METHODS: Anaesthetized open-chest rabbits underwent 30 min of coronary artery occlusion followed by 3 h of reperfusion. Before this, rabbits were randomized into one of five groups and underwent a treatment period consisting of either no intervention for 45 min (control; n = 10), or 30 min of 1 MAC halogenated anaesthetic inhalation followed by 15 min of washout. End-tidal concentrations of halogenated agents were 3.7% for sevoflurane (n = 11), 1.4% for halothane (n = 9), 2.0% for isoflurane (n = 11), and 8.9% for desflurane (n = 11). Area at risk and infarct size were assessed by blue dye injection and tetrazolium chloride staining. RESULTS: Mean (SD) infarct size was 54 (18)% of the risk area in untreated controls and 40 (18)% in the sevoflurane group (P > 0.05, ns). In contrast, mean infarct size was significantly smaller in the halothane, isoflurane, and desflurane groups: 26 (18)%, 32 (18)% and 16 (17)%, respectively (P < 0.05 vs control). CONCLUSIONS: Halothane, isoflurane and desflurane induced pharmacological preconditioning, whereas sevoflurane had no significant effect. In this preparation, desflurane was the most effective agent at preconditioning the myocardium against ischaemia.

Anesthetics, Inhalation↗

PubMed2001

Extracellular calcium modulates the effects of protamine on rat myocardium.

UNLABELLED: We studied the effects of protamine (10-300 microg. mL(-1)) as well as its interaction with heparin in rat left ventricular papillary muscles in vitro at calcium concentrations of 0.5 and 1 mM under low (isotony) and high (isometry) loads. Protamine induced a negative inotropic effect that was less pronounced at calcium 0.5 mM (active force at protamine 300 microg/mL, 84 +/- 20 vs 57 +/- 15% of baseline, P: < 0.05); whereas at calcium 1 mM there was a marked contracture of the muscle. For the smallest concentrations of protamine and at calcium 0.5 mM, we observed a moderate positive inotropic effect that was suppressed by nifedipine. Protamine induced a negative lusitropic effect under low load and decreased postrest potentiation, suggesting an impairment in the functions of the sarcoplasmic reticulum. Heparin was able to inhibit and reverse the negative inotropic effect of protamine. The negative inotropic effect of protamine is enhanced by an increase in extracellular calcium concentration. This negative inotropic effect is probably related to calcium overload and impairment in sarcoplasmic reticulum functions, and heparin can block these effects. IMPLICATIONS: The negative inotropic effect of protamine is enhanced by an increase in extracellular calcium concentration. This negative inotropic effect is probably related to calcium overload and impairment in sarcoplasmic reticulum functions, and heparin can block these effects.

Animals↗

PubMed2001

Interaction of protamine with alpha- and beta-adrenoceptor stimulations in rat myocardium.

BACKGROUND: Protamine alters the inotropic responses to beta-adrenoceptor stimulation, but its mechanism of action is not well-understood. Moreover, its interaction with alpha-adrenoceptor stimulation and the lusitropic (relaxation) response to beta-adrenoceptor stimulation remain unknown. METHODS: The effects of protamine (10 or 100 microg/ml) on the responses induced by phenylephrine and isoproterenol were studied in rat left ventricular papillary muscles. Inotropic and lusitropic effects were studied under low and high loads. The authors also studied the interaction of protamine with forskolin (50 microm) and dibutyryl 3',5'-cAMP (0.5 mm). Data are mean percentage of baseline active force +/- SD. RESULTS: In control groups, phenylephrine (135 +/- 17%, P < 0.05) and isoproterenol (185 +/- 44%, P < 0.05) induced a positive inotropic effect. Isoproterenol induced positive lusitropic effects under low and high loads. Protamine abolished the inotropic responses to alpha- (102 +/- 23%, not significant) and beta-adrenoceptor stimulations (99 +/- 17%, not significant) but did not modify the lusitropic responses to isoproterenol. Protamine abolished the inotropic responses to forskolin (89 +/- 6 vs. 154 +/- 20%, P < 0.05) and markedly decreased that of dibutyryl 3',5'-cAMP (132 +/- 31 vs. 167 +/- 30%, P < 0.05) but did not modify their lusitropic responses. CONCLUSIONS: Protamine abolished the inotropic responses to alpha- and beta-adrenoceptor stimulations but preserved the lusitropic responses to beta-adrenoceptor stimulation. Although protamine may act at several sites on the adrenoceptor stimulation cascade, one of its main sites of action is situated downstream from cAMP-mediated phosphorylation.

Adrenergic alpha-Agonists↗

PubMed2000

Severe heart failure secondary to 5-fluorouracil and low-doses of folinic acid: usefulness of an intra-aortic balloon pump.

OBJECTIVES: To report 5-fluorouracil in combination with folinic acid as a cause of severe nonischemic heart failure and to demonstrate the potential usefulness of an intra-aortic balloon pump. DESIGN: Case report. SETTING: An adult, 19-bed medical/surgical intensive care unit of a university hospital. PATIENTS: A patient, who developed severe heart failure secondary to 5-fluorouracil infusion with low-dose folinic acid, which was introduced to treat a rectal cancer, was transferred from a cancer institute to our intensive care unit 4 days after the treatment was initiated. INTERVENTIONS: Electrocardiography, determination of level of cardiac enzymes, echocardiography, radial arterial catheterization, mechanical ventilatory support, continuous venovenous hemodialysis, vasopressors, and secondary intra-aortic balloon pump. MEASUREMENT AND MAIN RESULTS: During shock, the patient's systolic blood pressure progressively decreased to 70 mm Hg, despite inotropic agents and vasopressors. Transesophageal echocardiography showed a calculated left ventricular ejection fraction within 20% with global hypokinesia. Electrocardiography showed sinus tachycardia with only nonspecific ST-T changes. Results of serial determination of levels of cardiac enzymes were not significant for myocardial infarction. Treatment with an intraaortic balloon pump was initiated and resulted in a dramatical improvement within 48 hrs. The patient was gradually weaned from vasopressors and the intra-aortic balloon pump. By the tenth day, echocardiography showed a septoapical hypokinesia with a 50% left ventricular ejection fraction. On the 30th day, the echocardiography was considered normal. CONCLUSION: Intravenous 5-fluorouracil in combination with low doses of folinic acid can induce severe nonischemic heart failure. In such a case, an intra-aortic balloon pump could be useful by providing left ventricular function support when inotropic agents and vasopressors fail to restore normal hemodynamics.

Adenocarcinoma↗

PubMed1999

[Severe hemorrhage from rupture of an intra-oral arteriovenous malformation].

We report the case of a 47-year-old woman with a sudden, spontaneous exsanguinating haemorrhage from an arteriovenous malformation of the mandible. The diagnosis was obtained with a contrast enhanced CT-scan and a digital subtraction angiography. As arterial embolisation was not available the lesion was treated surgically.

Angiography↗

PubMed1999

[Severe head injuries: effects of pre-hospital mechanical ventilation on capnia].

OBJECTIVE: To assess the effect on PaCO2 of mechanical ventilation during prehospital management of severely head-injured patients. STUDY DESIGN: Retrospective observational study. PATIENTS: Severely head-injured patients with Glasgow coma score < or = 8. All patients were sedated, with the trachea intubated and the lungs mechanically ventilated. METHODS: According to the capnia measured at the admission in the neurosurgical intensive therapy unit they were allocated into one of the following three groups: hypocapnia group (PaCO2 < 30 mmHg), recommended capnia group (PaCO2 = 30-38 mmHg) and hypercapnia group (PaCO2 > 38 mmHg). RESULTS: Out of the 42 patients with similarly severe head injuries, 19% were included in the recommended capnia group (PaCO2: 34 +/- 2 mmHg), 38% in the hypocapnia group (PaCO2: 23 +/- 3 mmHg) and 43% in the hypercapnia group (PaCO2: 47 +/- 7 mmHg). In all except three, PaO2 was above 95 mmHg. The settings of ventilatory parameters on the ventilators were similar. CONCLUSION: In 81% of patients, mechanical ventilation was inadequate as far as PaCO2 levels are concerned. Major hypocapnia and hypercapnia carry a potential risk for cerebral ischaemic. Therefore it is recommended to monitor PETCO2 during prehospital transport in medical ambulances and to determine arterial blood gases at arrival of severely head-injured patients in the admission unit for emergencies.

Adolescent↗

PubMed1998

Early hemodynamic variations assessed by an echo-Doppler aortic blood flow device in a severely burned infant: correlation with the circulating cytokines.

We describe the case of a seriously burned infant who suffered from a deep burn covering approximately 30% of his total body surface area. Because invasive hemodynamic monitoring is usually not suggested in infants, hemodynamic profile can be misunderstood. We tested a new echo-Doppler device to determine hemodynamic variation using a small esophageal probe specifically designed for newborns and infants. The aortic flowmeter was connected with satellite devices to obtain the hemodynamic profile, including aortic blood flow (ABF), preejection period, left ventricular ejection time, mean arterial pressure, heart rate, calculated stroke volume, calculated total systemic vascular resistance (TSVR), and end-tidal CO2 pressure. The positioning of the probe was easily obtained at each time. The hemodynamic management initially exhibited a hypovolemic status followed by a hyperdynamic profile, as suggested by a gradually increased ABF, which seemed similar to the variations currently reported in adult burn patients. Concurrent with hemodynamic determinations, plasma samples were drawn to measure interleukin-6 (IL-6), interleukin-1beta(IL-1beta), and tumor necrosis factor-alpha(TNF-alpha)levels. A consistent peak of IL-6 occurred simultaneously with the drop in TSVR. In contrast, no marked modifications were observed with IL-1beta and TNF-alpha. The same circulating cytokines moved alike in burned adults; IL-6 could partly explain the mechanisms of hemodynamic variation through the systemic inflammatory response syndrome. On the other hand, the echo-Doppler device could provide valuable noninvasive findings, allowing early improvement in resuscitation during the acute phase of critically burned infants and children.

Adult↗

PubMed1995

Uterine collagen during pregnancy in cattle.

Uteri were collected at the slaughter of non-pregnant dairy cattle and cattle at various stages of gestation. The weight of the whole uterus increased about 12-fold during the 9 month gestation period. The greatest increase was in the weight of the pregnant horn. The increase in weight of the uterine horns was accompanied by an increase in collagen content. The collagen concentration did not change. The collagen crosslink pyridinoline was identified in pregnant uterine tissues at a level of about 0.13 residues per mole of collagen; this level was the same at the beginning and end of pregnancy.

Amino Acids↗

PubMed1991

Uterine collagen during involution in cattle.

Post-partum involution of the bovine uterus was assessed by clinical examination and monitored biochemically by measuring the total urinary excretion of hydroxyproline and the collagen cross-link, pyridinoline. Uterine tissue contained 0.13 +/- 0.04 residues of pyridinoline per mole of collagen and negligible (less than 0.005 residues/mole) deoxypyridinoline. The pyridinoline/creatinine ratio was found to be a clearer and more reliable indicator of uterine resorption than the hydroxyproline/creatinine ratio. The amount of collagen cross-link excreted above baseline was equivalent to the amount of cross-link estimated to have been accumulated during pregnancy. Maximal excretion of pyridinoline occurred at day 6 and returned to baseline values in 2-3 weeks after parturition. An electron microscope study during the period of peak resorption revealed macrophage-like cells apparently engulfing or containing collagenous material, indicating phagocytic removal of the connective tissue.

Amino Acids↗

PubMed1987

The diagnosis of male infertility--prospective time-specific study of conception rates related to seminal analysis and post-coital sperm-mucus penetration and survival in otherwise unexplained infertility.

Infertile women without any inherent female infertility factors and able to secrete normal cervical mucus were studied prospectively in relation to post-coital sperm-mucus penetration (PCT) and their partner's seminal analysis, excluding men with azoospermia. Time-specific cumulative conception rates calculated as for life-table analysis were related to each measured seminal variable on routine analysis of 2-3 samples (volume, density, proportion with progressive motility, and proportion with normal morphology); to various derivatives from combinations of these variables; to seminal findings after vital staining; and to the PCT results. The best seminal predictor of fertility was the motile normal sperm density (MNSD), the 18 month conception rates being 57.4% +/- 4.6 (SE) and 30.2% +/- 5.9 (ratio 1.9, P less than 0.001) above and below a derived threshold value of 4 x 10(6)/ml. The PCT led to rates of 55.6% +/- 4.3 and 14.9% +/- 5.1 (ratio 3.73, P less than 0.001) for positive and negative results, respectively. The PCT also gave rise to a significantly distinct intermediate poor-positive sub-group (conception rate 30.6% +/- 9.0). Seminal analysis (the MNSD) did not affect the conception rate associated with a positive PCT but helped to discriminate further with a negative PCT (conception rates 22.5% +/- 8.7 with an MNSD above 4 x 10(6)/ml versus 5.6% +/- 4.8 below, P less than 0.05). The PCT was the single best predictor of fertility but seminal analysis (the MNSD) was of additional value after a negative PCT.

Cervix Mucus↗

PubMed1987

Concentrations of uterine luminal prostaglandins in mares with acute and persistent endometritis.

Intrauterine infusion of 1 per cent oyster glycogen solution was used to induce acute endometritis in four genitally normal mares. Numbers of viable neutrophils recovered in uterine washings had increased by 1 h after infusion and remained elevated for at least 72 h. There was a significant correlation between numbers of viable neutrophils and total protein concentrations and between prostaglandin (PG)F and PGE2 concentrations in washings. There was also a significant relationship between concentrations of 15-keto-13, 14-dihydro PGF2 alpha in plasma and PGF in washings. Intrauterine concentrations of PGF were influenced by cycle stage and in turn the induced acute endometritis interfered with normal ovarian function. Mares with persistent endometritis had significantly higher concentrations of PGF and total protein and percentage of neutrophils and mononuclear cells in washings than normal mares. White blood cells from mares were capable of producing PGF and PGE2 in vitro.

Acute Disease↗

PubMed1987

Effect of ovarian hormones on promotion of bactericidal activity by uterine secretions of ovariectomized mares.

The bactericidal and phagocytic activities of blood neutrophils suspended in uterine washings and the mobilization of neutrophils into the uterine lumen were studied in ovariectomized mares receiving oestradiol benzoate (N = 4), progesterone (N = 4) or oily vehicle (N = 4). Uterine lavage was performed sequentially up to 144 h after induction of endometritis by intrauterine infusion of glycogen (1%). There was no significant difference between the 3 groups in speed of mobilization of neutrophils into the uterus in the first 6 h after infusion but there were significantly more uterine luminal neutrophils in progesterone-treated than in oestradiol-treated mares by 24 h after infusion (P less than 0.01). Uterine washings collected from progesterone-treated mares at 0, 24 and 144 h were significantly worse at promoting bactericidal activity by neutrophils than washings from oestradiol-treated and control mares (P less than 0.001). In oestrogen-treated and control mares bactericidal activity had increased by 144 h but in progesterone-treated mares bactericidal activity remained low. Neither treatment nor time affected the ability of washings to opsonize yeast blastospores. Elevated concentrations of progesterone in plasma were therefore associated with decreased bactericidal activity of neutrophils suspended in uterine washings but the generation of C3b in washings did not appear to be affected by hormone treatment.

Animals↗

PubMed1986

Altered low density lipoproteins in peripheral vascular disease patients.

Several studies have shown that peripheral vascular disease (PVD) patients have abnormal lipoproteins. The mechanism whereby this abnormal lipid metabolism influences arterial occlusive disease in these PVD patients is not known. In the present study we found that low density lipoproteins (LDL) obtained from PVD patients have lower affinity to B receptor of normal fibroblasts compared to LDL obtained from control subjects. The nanograms of 125I LDL bound per milligram of B receptor was 254 +/- 19 for LDL from control subjects, 152 +/- 12 for LDL from PVD without diabetes, and 108 +/- 8 for PVD with diabetes (P less than 0.01). Further, the preincubation of LDL obtained from PVD patients with pentoxifylline (xanthine derivative used for PVD) increased the binding affinity of the LDL to B receptor sites from 107 +/- 9 to 210 +/- 34 (P less than 0.01). There was no significant difference in the binding properties of LDL with fibroblasts either from PVD patients (254 +/- 19) or control subjects (267 +/- 22) (P greater than 0.5), thereby suggesting that the number of receptor sites may be the same in both types of fibroblasts. From these results it can be concluded that defect in the metabolism of LDL may promote arterial occlusive disease seen in the PVD patients.

Aged↗

PubMed1986

Specific antibody in the equine genital tract following local immunisation and challenge infection with contagious equine metritis organism (Taylorella equigenitalis).

Antibody in serum, uterine and vaginal secretions was measured following local immunisation and experimental infection with the organism of contagious equine metritis (Taylorella equigenitalis). Intrauterine immunisation with killed T equigenitalis stimulated a systemic IgG titre and a uterine IgA and IgM response. Subsequent challenge with the organism, however, resulted in a characteristic metritis in both control and vaccinated mares. Antibody in serum and secretions was increased following challenge infection, dwarfing the response to immunisation. The local response was restricted to the IgA and IgM classes in both uterine and vaginal secretions. There was no elevation in local IgG antibody, although there was an increase in serum IgG in response to challenge infection. A second experimental challenge, following natural resolution of the initial infection and a period of reimmunisation, resulted in reduced clinical signs and bacterial isolation rates from both control and vaccinated mares, but no absolute protection from infection.

Animals↗

PubMed1985

Effect of cycle stage on immunoglobulin concentrations in reproductive tract secretions of the mare.

The effect of cycle stage on immunoglobulin and albumin levels in serum, follicular fluid, oviductal, uterine and vaginal secretions was measured. There was no variation in serum immunoglobulin levels during the oestrous cycle, although IgM levels were elevated in cyclic mares compared to non-cyclic (immature and anoestrous) animals. Similarly, there was no cyclical variation in follicular or oviductal protein concentrations. In the uterus, IgG and IgA levels relative to total protein were higher in oestrogenic than in progestagenic secretions, while the trend in relative IgM concentrations was reversed. Albumin levels were unchanged. In mares sampled repeatedly from the uterus and vagina during a single oestrous cycle, protein levels in secretions were affected by the collection technique. However, there was variation in absolute IgG, IgA, albumin and total protein concentrations, with maxima during dioestrus and minima at oestrus. Protein concentrations were higher in vaginal than in uterine secretions, although IgA relative to total protein was higher in the uterus than the vagina.

Albumins↗