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Biomedical subjects

B Denis

Publications and source records attributed to B Denis.

At least 19 recordsLinked to original sources
PubMed2006

Impact of cytopathologist expert on diagnosis and treatment of pancreatic lesions in current clinical practice. A series of 106 endoscopic ultrasound-guided fine needle aspirations.

OBJECTIVES: To evaluate the role of a cytopathologist expert in interpreting difficult pancreatic endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) in terms of impact on diagnostic yield and therapy in current clinical practice. METHODS: Retrospective study of 106 EUS-FNA performed between January 2002 and September 2004. Forty-seven cases of difficult interpretation by the local cytopathologist were mailed to an expert cytopathologist. The final diagnosis was established by histology obtained by either surgery (n=30), non-equivocal FNA (n=40) or core (n=8) biopsies, or by a mean follow-up of 14 months (n=28). RESULTS: EUS-FNA involved 68 solid lesions (SL). Specimens collected were adequate in 63%. The overall sensitivity of EUS-FNA for the diagnosis of malignancy of SL was 88% versus 72% for local cytopathologist and 89% for expert. EUS-FNA with the reevaluation by expert of 39 SL gave a therapeutic impact in 47% of SL. Thirty-eight cystic lesions (CL) were evaluated. Specimens collected were adequate for cytology in 84% of cases and for biochemistry in 79%. The sensitivity of imaging+EUS-FNA+/-biochemistry for the diagnosis of a surgical CL was 58% with a therapeutic impact in 39.5%. CONCLUSION: Pancreatic EUS-FNA is an easy technique for experienced endosonographers, which can be safely performed on an outpatient basis. The possibility of mailing difficult cases to an expert cytopathologist increases the diagnostic yield. In these circumstances, EUS-FNA has a therapeutic impact in current practice in nearly one out of two pancreatic lesions.

Adenocarcinoma↗
PubMed2006

Evidence for a substantial role of sharing of injecting paraphernalia other than syringes/needles to the spread of hepatitis C among injecting drug users.

In industrialized countries, transmission of hepatitis C occurs primarily through injecting drug use. Transmission of hepatitis C in injecting drug users is mainly associated with the sharing of contaminated syringes/needles, although evidence for risk of hepatitis C infection through sharing of other injecting paraphernalia is increasing. In this paper, the independent effects of sharing paraphernalia other than syringes/needles have been estimated. The prevalence and force of infection were modelled using three serological data sets from drug users in three centres in Belgium as a function of the sharing behaviour. It was found that sharing of materials other than syringes/needles indeed seemed to contribute substantially to the spread of hepatitis C among injecting drug users.

Adolescent↗
PubMed2005

Phaeochromocytoma treated by en bloc resection including the suprarenal caudal vena cava in a dog.

A 10-year-old, neutered male Cairn terrier was examined after experiencing intermittent vomiting of several months' duration and sudden onset of acute depression. Abdominal ultrasound examination revealed an adrenal mass invading the suprarenal part of the caudal vena cava. The vascular invasion could not be corrected so en bloc ligation/excision of the adrenal neoplasm and the suprarenal part of the vena cava was performed. Microscopic examination identified an adrenal phaeochromocytoma. The dog recovered well and had no significant vascular or renal dysfunction at follow-up 20 months after surgery. To the authors' knowledge, this is the first report of a dog surviving long term after resection of the suprarenal caudal vena cava.

Abdomen↗
PubMed2004

High cerebral scyllo-inositol: a new marker of brain metabolism disturbances induced by chronic alcoholism.

Cerebral metabolic changes that concur to motor and/or cognitive disorders in actively drinking alcoholics are not well established. We tested the hypothesis that chronic alcoholics exhibit profound alterations in the cerebral metabolism of scyllo-inositol. Brain metabolism was explored in nine actively drinking and 11 recently detoxified chronic alcoholics by in vivo brain (1)H-MRS and in vitro(1)H-MRS of blood serum and cerebrospinal fluid. The cohort was composed of individuals with acute, subacute or chronic encephalopathy or without any clinical encephalopathy. Chronic alcoholism is associated with a hitherto unrecognized accumulation of brain scyllo-inositol. Our results suggest that scyllo-inositol is produced within the central nervous system and shows a diffuse but heterogenous distribution in brain where it can persist several weeks after detoxification. Its highest levels were observed in subjects with a clinically symptomatic alcohol-related encephalopathy. When detected, brain scyllo-inositol takes part in a metabolic encephalopathy since it is associated with reduced N-acetylaspartate and increased creatine. High levels of cerebral scyllo-inositol are correlated with altered glial and neuronal metabolism. Our findings suggest that the accumulation of scyllo-inositol may precede and take part in the development of symptomatic alcoholic metabolic encephalopathy.

Adult↗
PubMed2003

Metabolic counterpart of decreased apparent diffusion coefficient during hyperacute ischemic stroke: a brain proton magnetic resonance spectroscopic imaging study.

BACKGROUND AND PURPOSE: Recent studies have shown that the brain ischemic area defined by the map of decreased apparent diffusion coefficient (ADC) obtained by diffusion-weighted imaging (DWI) during the first hours of ischemic stroke includes a significant part of ischemic penumbra. We hypothesize that the misjudgment of the final infarct size by ADC mapping may be related to a restricted ability of DWI to capture variations in the intensity of cellular suffering. In an attempt to characterize metabolically the hypoperfused brain parenchyma, we studied the relationship between ADC values and brain metabolic parameters measured by proton MR spectroscopic imaging (SI). METHODS: Six patients with hyperacute ischemic stroke were explored within the first 7 hours after onset with the use of a MR protocol including T2*-weighted MRI, DWI, SI, perfusion-weighted imaging, and MR angiography. RESULTS: This study demonstrates, for the first time, a wide gradient of ischemia-related metabolic anomalies within the abnormal area delineated by DWI during hyperacute ischemic stroke. In the narrow range of decreased mean ADC values (0.60 to 0.40 x 10(-9) m2 x s(-1)), a 33% decrease in mean ADC is associated with a 122% increase in lactate/N-acetyl aspartate ratio. Mean ADC values never fall below 0.40 x 10(-9) m2 x s(-1) within the severely affected ischemic tissue, while SI still detects a large metabolic heterogeneity inside areas showing similar decreased mean ADC values close to this threshold. CONCLUSIONS: Our results indicate that the region of very low mean ADC values observed during hyperacute ischemic stroke contains areas of various tissue damage intensity characterized by SI in relation to different stages of cellular metabolic injury. This observation may explain why ADC mapping does not reliably predict final infarct size.

Acute Disease↗
PubMed2001

Thiopalmitoylation of myelin proteolipid protein epitopes enhances immunogenicity and encephalitogenicity.

Proteolipid protein (PLP) is the most abundant protein of CNS myelin, and is posttranslationally acylated by covalent attachment of long chain fatty acids to cysteine residues via a thioester linkage. Two of the acylation sites are within epitopes of PLP that are encephalitogenic in SJL/J mice (PLP(104-117) and PLP(139-151)) and against which increased immune responses have been detected in some multiple sclerosis patients. It is known that attachment of certain types of lipid side chains to peptides can result in their enhanced immunogenicity. The aim of this study was to determine whether thioacylated PLP peptides, as occur in the native protein, are more immunogenic than their nonacylated counterparts, and whether thioacylation influences the development of autoreactivity and experimental autoimmune encephalomyelitis. The results show that in comparison with nonacylated peptides, thioacylated PLP lipopeptides can induce greater T cell and Ab responses to both the acylated and nonacylated peptides. They also enhanced the development and chronicity of experimental autoimmune encephalomyelitis. Synthetic peptides in which the fatty acid was attached via an amide linkage at the N terminus were not encephalitogenic, and they induced greater proportions of CD8+ cells in initial in vitro stimulation. Therefore, the lability and the site of the linkage between the peptide and fatty acid may be important for induction of encephalitogenic CD4+ T cells. These results suggest that immune responses induced by endogenous thioacylated lipopeptides may contribute to the immunopathogenesis of chronic experimental demyelinating diseases and multiple sclerosis.

Acylation↗
PubMed2001

Regional metabolite levels of the normal posterior fossa studied by proton chemical shift imaging.

MR spectroscopy of the posterior fossa is pitted with numerous technical difficulties. It is, however, of great clinical interest in the study of the degenerative diseases and tumors of this area. We have developed a method to perform 2D CSI of this area, by using a sagittal slice and a careful positioning of outer volume saturation. We performed this acquisition in 30 healthy volunteers to determine the normal metabolic ratios in five voxels of this area (mesencephalon, pons, medulla oblongata, vermis, cerebellar white matter). The main technical difficulty was magnetic field inhomogeneity in the lower brainstem generated by dental alloys. However, 88% of the voxels were of sufficient quality to be analyzed. The statistically significant regional variations were a higher NAA/Cr ratio in the pons than in the medulla oblongata, higher Cho/Cr in the pons than in the mesencephalon and higher Cho/Cr in the cerebellar white matter than in the vermis. We conclude that 2D CSI of the brainstem, although technically delicate can be performed in most patients.

Brain↗
PubMed2001

Distribution of S-layers on the surface of Bacillus cereus strains: phylogenetic origin and ecological pressure.

Bacillus anthracis, Bacillus cereus and Bacillus thuringiensis have been described as members of the Bacillus cereus group but are, in fact, one species. B. anthracis is a mammal pathogen, B. thuringiensis an entomopathogen and B. cereus a ubiquitous soil bacterium and an occasional human pathogen. In two clinical isolates of B. cereus, in some B. thuringiensis strains and in B. anthracis, an S-layer has been described. We investigated how the S-layer is distributed in B. cereus, and whether phylogeny or ecology could explain its presence on the surface of some but not all strains. We first developed a simple biochemical assay to test for the presence of the S-layer. We then used the assay with 51 strains of known genetic relationship: 26 genetically diverse B. cereus and 25 non-B. anthracis of the B. anthracis cluster. When present, the genetic organization of the S-layer locus was analysed further. It was identical in B. cereus and B. anthracis. Nineteen strains harboured an S-layer, 16 of which belonged to the B. anthracis cluster. All 19 were B. cereus clinical isolates or B. thuringiensis, except for one soil and one dairy strain. These findings suggest a common phylogenetic origin for the S-layer at the surface of B. cereus strains and, presumably, ecological pressure on its maintenance.

Bacillus anthracis↗
PubMed2001

[Epileptic seizures, hemiplegia and hyperglycemia: late discovery of a localized cortical dysplasia].

A 56-year-old woman was hospitalized with a right hemiplegia and aphasia evoking a cerebral infarction. In fact the neurologic deficits were of post-ictal origin, secondary to a partial epilepsy which began a few weeks before, at the same time as a polyuria-polydipsia syndrome revealing diabetes mellitus. This case illustrates the possibility for a partial epilepsy to occur in relation with a nonketotic hyperglycemia. If in most of those cases there is no underlying cortical lesion, in some observations the hyperglycemia is associated with an infarction. In our case the MRI revealed another type of lesion: a cortical dysplasia in form of a unilateral micropolygyria with a perisylvian distribution centered around the insula. The discovery of a cortical dysplasia at such an age is very unusual.

Cerebral Cortex↗
PubMed2000

Synthesis of palmitoyl-thioester T-cell epitopes of myelin proteolipid protein (PLP). Comparison of two thiol protecting groups (StBu and Mmt) for on-resin acylation.

In order to test the effect of thiopalmitoylation on the encephalitogenic properties of two proteolipid protein (PLP) T-cell epitopes, we have studied the on-resin S-palmitoylation of peptides, synthesized using the Fmoc/tBu strategy. The use of two Cys protecting groups was investigated: the tert-butylsulfenyl (StBu) and the methoxytrityl (Mmt). Our studies show that the ease of deprotection of the thiol protected with StBu was sequence dependent. The deprotection of Cys(StBu) was difficult in the case of the two peptides PLP(104-117) and PLP(139-151). Neither of the two Cys(StBu) (Cys108 and Cys140, respectively) could be deprotected with tributylphosphine. Beta-mercaptoethanol was only efficient for the deprotection of Cys(StBu)140 at 85 degrees C and at 135 degrees C for Cys108. The two palmitoylated peptides could be obtained in good yield starting from Cys protected with Mmt. Our conclusion is that the Mmt group is the more versatile protecting group of the thiol for use in the on-resin synthesis of thiopalmitoylated peptides.

Acylation↗
PubMed2000

A scenario for the hobo transposable element invasion, deduced from the structure of natural populations of Drosophila melanogaster using tandem TPE repeats.

Temporal surveys of hobo transposable elements in natural populations reveal a historical pattern suggesting a recent world-wide invasion of D. melanogaster by these transposons, perhaps following a recent horizontal transfer. To clarify the dynamics of hobo elements in natural populations, and thus to provide further data for our understanding of the hobo invasion, TPE tandem repeats, observed in the polymorphic S region of the element, were used as molecular markers. The number of TPE repeats was studied in 101 current populations from around the world, and in 63 strains collected in the past. This revealed a geographical distribution which seems to have been stable since the beginning of the 1960s. This distribution is compatible with a number of hypotheses for the dynamics of hobo elements. We propose a scenario based on an invasion in two stages: first, a complete invasion by elements with three TPE repeats, followed by the beginning of a new invasion involving hobo elements with five or seven repeats.

Animals↗
PubMed2000

Successful prolonged cardiopulmonary resuscitation after a combined intoxication with a tricyclic antidepressant, a benzodiazepine and a neuroleptic.

We report the case of a patient who co-ingested a tricyclic antidepressant (amitriptyline), benzodiazepines (alprazolam and lormetazepam) and a neuroleptic drug (prothipendyl). Major neurologic and cardiac symptoms occurred including a prolonged cardiac arrest. The cardiopulmonary resuscitation phase was complicated by a haematoma of the liver treated by a left hepatectomy. The clinical features and management of this combined intoxication are discussed.

Adult↗
PubMed1999

Long-term additive prognostic value of thallium-201 myocardial perfusion imaging over clinical and exercise stress test in low to intermediate risk patients : study in 1137 patients with 6-year follow-up.

BACKGROUND: The exercise treadmill test (ETT) and Tl201 single proton emission computed tomography (SPECT) are of short- to medium-term prognostic value in coronary heart disease. We assessed the long-term prognostic value of these tests in a large population of patients with low- to intermediate risk of cardiac events. METHODS AND RESULTS: One thousand one hundred thirty-seven patients (857 men, age 55+/-9 years) referred for typical (62.1%) or atypical (22.4%) chest pain, or suspected silent ischemia (15.5%), were followed up for 72+/-18 months. Overall mortality was higher after strongly positive (ST depression >2 mm, or >1 mm for a workload </=75 W) (2. 36%/y) or nondiagnostic ETT (1.63%/y) than after normal (0.85%/y) or positive ETT (1.37%/y) (P=0.002), and after abnormal SPECT than after normal SPECT (1.60%/y versus 0.68%/y, P=0.001). The major cardiac event rate (cardiac death or myocardial infarction [MI]) was 0.88%, 1.59%, 2.10%, and 2.13%/y after negative, positive, strongly positive, and nondiagnostic ETT, respectively (P=0.003), and 0.56%, 1.43%, and 2.05%/y in patients with 0, 1 to 2, and >/=3 abnormal segments on SPECT, respectively (P<0.002). An abnormal SPECT was predictive of MI (P<0.001), whereas ETT was not. In multivariate analysis, SPECT was of incremental prognostic value over clinical and ETT data for predicting overall mortality and major cardiac events. CONCLUSIONS: The incremental predictive value of SPECT is maintained over 6 years and is particularly relevant after positive, strongly positive, and nondiagnostic ETT.

Adult↗
PubMed1999

Characterization of permissivity for hobo-mediated gonadal dysgenesis in Drosophila melanogaster.

The hobo transposon is responsible for one of the three hybrid dysgenic systems that have been described in Drosophila melanogaster. Most studies on the hobo dysgenic system have been carried out using the PM system as a reference. However, these two systems differ significantly. In particular, several studies have failed to find any correlation between the molecular structures of hobo elements, the instability of the transposon and the incidence of gonadal dysgenic (GD) sterility. On the other hand, no study of the ability of females to permit hobo activity in their progeny when they are crossed with males harboring active hobo elements (permissivity) has yet been reported. In order to investigate the parameters involved in hobo permissivity, four E strains were studied with regard to the molecular nature of their hobo sequences and the GD sterility induced by a controlled source of hobo transposase. We show that hobo permissivity varies both within and between E strains. Moreover, permissivity decreases with age in E females. Our results are discussed with respect to similar phenomena that have been described in relation to the reactivity of the IR dysgenic system.

Aging↗
PubMed1999

Prediction of cardiovascular events in clinically selected high-risk NIDDM patients. Prognostic value of exercise stress test and thallium-201 single-photon emission computed tomography.

OBJECTIVE: We evaluated the prognostic value of an exercise stress test and thallium-201 scintigraphy for the prediction of cardiac events in selected high-risk NIDDM patients. RESEARCH DESIGN AND METHODS: NIDDM patients (n = 158, 105 men, aged 63 +/- 9 years) with two or more of the following criteria were prospectively included: age > or = 65 years, active smoking, hypertension > 160/95 mmHg, hypercholesterolemia (cholesterol > 5.70 mmol/l or LDL > 3.10 mmol/l), peripheral artery disease, abnormal rest electrocardiogram, or microalbuminuria (20-200 micrograms/min). An exercise-stress scintigraphy was performed in 77 patients able to exercise, while a dipyridamole scintigraphy was performed in 80 patients unable to exercise. Follow-up was 23 +/- 17 months. Major end points were cardiac deaths or nonfatal myocardial infarction. RESULTS: The annual event rate was 7.31% (deaths: 8, myocardial infarction: 14). Independent predictors of events were as follows: an age > 60 (P = 0.02), an abnormal rest electrocardiogram (P = 0.02), microalbuminuria (P = 0.001), the inability to exercise (P = 0.009), and the presence of more than two defects on scintigraphy (P = 0.001). A cardiac death occurred in 1.3% of patients able to exercise versus 8.8% of patients unable to exercise (odds ratio = 6.8, P = 0.001). Among patients unable to exercise, large perfusion defects corresponded to an annual mortality rate of 22.3%. Conversely, the negative predictive value of a normal scintigraphy for the occurrence of death was 97%. CONCLUSIONS: Inability to exercise and large perfusion defects on thallium-201 scan are major predictors of future death and myocardial infarction in high-risk NIDDM patients.

Activities of Daily Living↗
PubMed1999

[Left branch portal vein thrombosis associated with hyperhomocysteinemia].

A 34 year-old man, who was a smoker, was hospitalised because of severe epigastric and right upper quadrant pain. An isolated left branch portal vein thrombosis was diagnosed using ultrasonography and arteriography. Two thrombogenic pathologies were found: i) a latent myeloproliferative syndrome with spontaneous presence of erythroid colony forming unit (CFU-E) in bone marrow culture, normal blood cell count, platelet count and medullogram; ii) a hyperhomocysteinemia associated with low serum folate levels and a methyl tetrahydrofolate reductase mutation. The association of these two factors probably resulted in portal vein thrombosis. This is the first adult case of a portal vein thrombosis associated with hyperhomocysteinemia. Increased homocysteine serum levels could be a previously unrecognized factor for portal vein thrombosis. Homocysteinemia should be systematically investigated in patients with idiopathic portal vein thrombosis since folate supplements could prevent deleterious vascular effects of hyperhomocysteinemia.

Adult↗
PubMed1998

Arrhythmic cardiac arrest due to isolated coronary artery spasm: long-term outcome of seven resuscitated patients.

OBJECTIVES: Our aim was to look at the clinical features and long-term follow-up of seven patients without coronary artery disease, who had a history of life-threatening ventricular arrhythmias due to coronary spasm. BACKGROUND: Arrhythmic cardiac arrest due to isolated coronary spasm is rare, and there is limited information on the patients affected by this entity alone. METHODS: The seven patients were recruited retrospectively from a cohort of survivors of cardiac arrest. None had a history of angina pectoris, structural heart disease or significantly narrowed coronary segments. All had a positive ergonovine provocation test result. RESULTS: The patients' mean age was 44 years; three were male and four female. All were habitual cigarette smokers. No arrhythmias were induced on programmed ventricular stimulation; corrected QT interval (QTc) and corrected JT interval (JTc) dispersion were within normal ranges. After the ergonovine provocation test, treatment with calcium channel blocking agents (diltiazem, verapamil, nifedipine or amlodipine) was initiated at a dose determined by titration until a negative test result was obtained. At a mean follow-up interval of 58 months for the total group, six patients remained free of symptoms, whereas the one patient who did not stop smoking had a new cardiac arrest despite treatment for coronary spasm. CONCLUSIONS: A favorable long-term outcome may be expected in survivors of cardiac arrest due to coronary spasm, in the absence of significant coronary artery disease. Calcium channel blockers are the most appropriate therapy in these patients. These observations provide further evidence for the role of silent ischemia in cardiovascular death.

Adult↗