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Biomedical subjects

D Mathieu

Publications and source records attributed to D Mathieu.

At least 73 records · Page 4Linked to original sources
PubMed1997

Dobutamine improves gastrointestinal mucosal blood flow in a porcine model of endotoxic shock.

OBJECTIVE: To test the hypothesis that saline solution plus dobutamine increases gastrointestinal mucosal perfusion better than saline solution alone in a model of endotoxic shock. DESIGN: Prospective, randomized, unblinded study. SETTING: Animal research laboratory affiliated with a university teaching hospital. SUBJECTS: Twelve female pigs, weighing 30 to 32 kg. INTERVENTIONS: Animals were anesthetized, and their lungs were mechanically ventilated. Catheters were inserted into the right atrium, pulmonary artery, and carotid artery for blood sampling and blood pressure and cardiac output measurements. A tonometer and a laser Doppler probe were placed in the lumen of the stomach and the ileum for determination of mucosal acid-base status and measurement of mucosal blood flow. Group 1 animals (n = 6) received an infusion (T = 0 min) of 150 mcirog/kg Escherichia coli endotoxin and normal saline solution (0.3 mL/kg/min). Group 2 animals (n = 6) received an infusion of endotoxin and were resuscitated with the same method as used in group 1, but an infusion of dobutamine (5 microg/kg/min) was begun at T = 60 mins, and continued for the duration of the experiment. MEASUREMENTS AND MAIN RESULTS: Both experimental regimens produced shock, with decreased mean arterial pressure and systemic vascular resistance, without change in cardiac output and oxygen delivery. Endotoxin plus saline infusion decreased gastrointestinal mucosal blood flow to <60% of baseline and decreased gastrointestinal pH. In contrast, gastrointestinal mucosal blood flow returned to baseline values, and intramucosal pH tended to normalize by the end of the saline solution plus dobutamine resuscitative protocol. CONCLUSION: Compared with saline solution alone, saline solution plus dobutamine increased blood flow to the gastrointestinal mucosa, and may have partially improved oxygenation.

Animals↗
PubMed1997

Limits of commercial molecular tests for diagnosis of pulmonary tuberculosis.

Several studies report high specificity, but variable sensitivity, of Amplified Mycobacterium tuberculosis Direct Test (AMTDT, Gen-Probe) based on ribosomal ribonucleic acid (rRNA) amplification and Amplicor Mycobacterium tuberculosis test (Amplicor, Roche) based on deoxyribonucleic acid (DNA) amplification for diagnosis of pulmonary tuberculosis. We have retrospectively evaluated these assays on selected acid-fast bacilli (AFB)-positive and -negative smear specimens and compared the results obtained from nucleic acid amplification with those of AFB staining of semi-quantitative cultures as determined by radiometric Bactec and Löwenstein-Jensen cultures. In comparison to cultures, Amplicor and AMTDT assays exhibited identical overall sensitivities of 80%, while the staining had a lower sensitivity of 62%. The sensitivities of Amplicor and AMTDT were 98% and 100%, respectively, for the AFB-positive specimens, and 50 and 46%, respectively for the AFB-negative specimens in comparison to cultures. The sensitivities of both assays appeared similar, and were directly related to the number of bacilli in the specimens studied. The low sensitivity (50%) for smear-negative specimens showed that current amplification assays may be unsuitable to replace cultures for diagnosis of tuberculosis. The decision to perform these molecular techniques should result from close co-operation between clinicians and microbiologists, taking into account the sensitivity results reported here, as well as the expense of the assays.

DNA↗
PubMed1997

Benign liver tumors.

This article focuses on the main clinicopathologic and MR findings in the more frequent benign liver lesions (excluding hemangiomas) such as cysts, focal nodular hyperplasia, hepatocellular adenoma, and fatty tumors. These entities raise several questions concerning their pathogenesis, differential diagnosis from various malignant tumors or pseudotumoral hepatic lesions, and management that remain frequently controversial.

Humans↗
PubMed1997

[Anaerobic infections of the soft tissues].

Anaerobic soft tissue infections are still life threatening infections. Although their frequency is actually moderate; they remain severe because physicians are often insufficiently aware of them. Although the classification between myonecrosis and necrotizing fasciitis is still valid, these infections share so many points in common that they can be considered together. Their origin is often traumatic or surgical but may also be secondary to an ulcer or a small wound in a high-risk patient: arteriosclerotic, diabetic. Hypoxia, traumatic muscle crush, heavy bacterial contamination as well as incorrect antibiotic prophylaxis are the major reasons for their occurrence. Management consists of antibiotics adapted to both anaerobic and associated aerobic bacteria, large and early surgical debridement, but with conservative excision, and intensive hyperbaric oxygen therapy. Strict prevention measures must be applied to avoid their occurrence.

Bacteria, Anaerobic↗
PubMed1996

[Carbon monoxide poisoning].

Carbon monoxide (CO) poisoning still represents a frequent and severe casualty in France. Aside from the well-known effect of CO on hemoglobin, the role of CO binding to other hemoproteins like myoglobin and cytochrome a3 has been more recently recognized. Moreover, in addition to these hypoxic injuries, the reoxygenation phase may itself induce toxic effects by a mechanism close to the ischemia-reperfusion phenomenon. Clinical manifestations include neurologic disturbances, cardiac arrhythmia, respiratory and circulatory failures which usually disappear with removal from toxic atmosphere and administration of oxygen. However, long term neurologic manifestations may occur and lead to important functional impairment and disability. Hyperbaric oxygen is actually the treatment of choice to avoid the occurrence of delayed sequelae. HBO is advocated in every patient who remains comatose on hospital admission, who has lost consciousness during toxic exposure or with persisting neurologic abnormalities. CO poisoned pregnant women should also undergo HBO.

Carbon Monoxide Poisoning↗
PubMed1996

[Role of magnetic resonance imaging in liver pathology].

The increasingly common use of ultrasound examination of the liver has led to increased detection of hepatic tumours, showing a hitherto unsuspected prevalence. Improved techniques in MRI, such as dynamic sequences and new contrast media, are ameliorating the detection and characterization of the lesions, in particular with regard to computed tomography. In addition, since MRI is more sensitive to different components than in computed tomography, it permits better study of diffuse diseases such as haemochromatosis or fatty infiltration, particularly in pseudotumoural forms. The continuing progress in system improvement makes MRI an excellent method for diagnosis of bile duct disorders, especially in case of obstruction.

Biliary Tract Diseases↗
PubMed1996

Needle biopsy of hepatocellular carcinoma: assessment of prognostic contribution of histologic parameters including proliferating cell nuclear antigen labeling and correlations with clinical outcomes. Group d'Etude et de Traitement du Carcinoma Hépatocellulaire.

BACKGROUND: Although many studies concerning the prognostic factors of resected hepatocellular carcinoma have been performed, the prognostic information provided by needle biopsy of these tumors has not yet been extensively studied. METHODS: One hundred twenty-four white patients with histologically-confirmed hepatocellular carcinoma were entered into a prospective study from 1990 to 1992 with followed-up through October 1994. Most of the patients had cirrhosis (79%). Patients were classified according to Okuda's staging: Stage I (50%), Stage II (47%), and Stage III (3%). The one-year survival rate was estimated at 58% in Okuda's Stage I, and 15% in Stages II and III. Edmondson's grading, mitotic index, and proliferating cell nuclear antigen labeling index were studied on each biopsy. Univariate and multivariate analyses were performed to determine the prognostic significance of the different parameters. RESULTS: According to Edmondson's critera, 13 of the hepatocellular carcinomas were Grade I, 63 Grade II, 42 Grade III, and 6 Grade IV. There was a significant correlation between Edmondson's grade, mitotic index, and proliferating cell nuclear antigen labeling index (P < 0.01). Univariate analysis showed both the histologic grade (P < 0.001) and mitotic index (P < 0.05) correlated with survival. Cox's model indicated that Edmondson's grading yields additional prognostic information for Okuda's staging (P < 0.001). The one-year survival rate for Okuda's Stage I was 76% for Edmondson's Grades I + II versus 23% for Grades III + IV. CONCLUSIONS: Edmondson's grading appears to be an important prognostic parameter for patients with hepatocellular carcinoma, and could help stratify patients for clinical trials.

Adult↗
PubMed1996

Imaging of metastases to the liver.

Metastatic disease to the liver is an important disease from the diagnostic, prognostic and therapeutic points of view. Different imaging modalities, such as US, CT, scintigraphy, and MRI, have been used for detection, characterization, therapy planning, and follow-up of this disease with variable degrees of success and failure. This review handles the problems which face the different imaging modalities in diagnosis of liver metastases in view of the pathological background of the disease. It also discusses the indications, strong points, and shortcomings of each of the imaging modalities in diagnosis of metastases, and surveys the recent efforts done to improve their performance through the optimization of quality control and in the innovations in the field of contrast agents. Finally, a protocol is suggested for the clinical management of patients with liver metastases to optimize cost-effectiveness of the imaging modalities in this era of multimodality approach in diagnostic imaging.

Cost-Benefit Analysis↗
PubMed1996

Calcification in focal nodular hyperplasia: a new problem for differentiation from fibrolamellar hepatocellular carcinoma.

PURPOSE: To describe calcification in focal nodular hyperplasia (FNH) of the liver, which poses a new problem for the differentiation of FNH from fibrolamellar hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Ultrasound, computed tomography, and magnetic resonance imaging findings of 357 FNH lesions diagnosed in the past 5 years in 295 patients (274 female, 21 male; aged 14-72 years) were retrospectively reviewed with emphasis on intralesional calcification. RESULTS: Calcifications were seen in five FNH lesions (1.4%) as small, solitary spots located centrally or peripherally within the lesions. Morphologic features of these calcifications were similar to those of calcifications in two of six fibrolamellar HCCs in the same period. CONCLUSION: Calcification in FNH is a rare and atypical finding that poses further difficulty for differentiation from fibrolamellar HCC.

Adult↗
PubMed1996

Detection of hepatic metastases: ferumoxides-enhanced MR imaging versus unenhanced MR imaging and CT during arterial portography.

PURPOSE: To prospectively compare the diagnostic accuracy of computed tomography (CT) during arterial portography (CTAP) with that of unenhanced and ferumoxides-enhanced magnetic resonance (MR) imaging at 0.5 T in the detection of hepatic metastases. MATERIALS AND METHODS: Four pairs of radiologists independently assessed the metastatic involvement of 134 hepatic segments (31 with and 103 without metastasis) in 17 patients at unenhanced and ferumoxides-enhanced spin-echo and gradient-echo MR imaging (alone and in combination) and at CTAP. The diagnostic performance of the various imaging modalities was assessed by means of receiver operating characteristic analysis. RESULTS: The accuracy of CTAP, unenhanced MR imaging (combined unenhanced sequences), and ferumoxides-enhanced MR imaging (combined contrast material-enhanced sequences) was 0.925, 0.908, and 0.951, respectively. Ferumoxides-enhanced MR imaging was significantly more accurate (P < .05) than unenhanced MR imaging and CTAP. When 14 segments containing cysts were excluded, the difference between ferumoxides-enhanced MR imaging and CTAP was no longer statistically significant (P = .1). CONCLUSION: Ferumoxides-enhanced MR imaging is more accurate than unenhanced MR imaging and at least as accurate as CTAP for the detection of hepatic metastases.

Adult↗
PubMed1996

Skeletal muscle microvascular blood flow and oxygen transport in patients with severe sepsis.

To compare skeletal muscle microvascular blood flow at rest and during reactive hyperemia in septic patients, a prospective, controlled trial was conducted on 16 patients with severe sepsis and a control group of 10 patients free of infection in the intensive care unit of a university hospital. Systemic hemodynamics, whole-body oxygen transport, and skeletal muscle microvascular blood flow at rest and during reactive hyperemia were measured. Reactive hyperemia was produced by arrest of leg blood flow with a pneumatic cuff; on completion of the 3 min ischemic phase the occluding cuff was rapidly deflated to 0. Hemodynamic and oxygen-derived variables were determined invasively. Skeletal muscle microvascular blood flow data were obtained using a laser Doppler flowmetry technique and values expressed in millivolts. Whole-body oxygen delivery in septic patients was increased compared with control subjects. Resting skeletal muscle blood flow was decreased in septic patients compared with control subjects (233 +/- 52 versus 394 +/- 93 mV; p < 0.05). Peak flow during reactive hyperemia was also decreased in septic patients compared with control subjects (380 +/- 13 versus 2,033 +/- 853 mV; p < 0.05). Cyclic variation in blood flow (vasomotion) was observed in control subjects but not in septic patients. Skeletal muscle microvascular perfusion is altered in patients with severe sepsis despite normal or elevated whole-body oxygen delivery. These microvascular abnormalities may further compromise tissue nutrient flow and may contribute to the development of organ failure in septic patients.

APACHE↗
PubMed1996

The contrasting effects of dobutamine and dopamine on gastric mucosal perfusion in septic patients.

To test the hypothesis whether or not dobutamine or dopamine infusion increases gastric mucosal perfusion, a prospective randomized crossover trial was conducted on 10 septic patients in the intensive care unit of a university hospital. Systemic hemodynamic, oxygen transport, and gastric perfusion assessed by gastric intramucosal pH and laser Doppler flowmetry were measured at baseline and after administration of dobutamine or dopamine (5 micrograms/kg/min). Both increased oxygen transport. In response to dobutamine, gastric mucosal blood flow increased (+32 +/- 14% from baseline; p < 0.05), gastric tonometered PCO2 and gastric arterial PCO2 difference decreased (58 +/- 7 versus 52 +/- 7 mm Hg; p < 0.05; 16.8 +/- 7.0 versus 10.5 +/- 7.2 mm Hg; p < 0.05), and intramucosal pH increased (7.23 +/- 0.05 versus 7.29 +/- 0.06; p < 0.05). In response to dopamine, gastric mucosal blood flow decreased (-28 +/- 8% from baseline; p < 0.05), gastric tonometered PCO2, gastric-arterial PCO2 difference, and calculated intramucosal pH were unchanged (58 +/- 7 versus 61 +/- 9 mm Hg, ns; 16.8 +/- 7.0 versus 18.9 +/- 8.4 mm Hg, ns; 7.24 +/- 0.05 versus 7.21 +/- 0.06, ns). We speculated that despite an oxygen transport increase, dobutamine and dopamine have affected differently gastric mucosal perfusion in septic patients.

Acid-Base Equilibrium↗