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Biomedical subjects

B Husson

Publications and source records attributed to B Husson.

At least 19 recordsLinked to original sources
PubMed2006

Utilization of municipal solid waste incineration (MSWI) fly ash in blended cement Part 2. Mechanical strength of mortars and environmental impact.

This second of two articles dealing with the utilization of MSWI fly ash in blended cement studies the effects of two variants of the stabilization process on the behavior of the treated fly ash (TFA) introduced into cement-based mortars. From a technological point of view, the modifications of the process are very efficient and eliminate the swelling produced by the introduction of MSWI fly ash in cement-based mortars. TFA has a significant activity in cement-based mortars and can also advantageously replace a part of the cement in cement-based material. From an environmental point of view, the results of traditional leaching tests on monolithic and crushed mortars highlight a poor stabilization of some harmful elements such as antimony and chromium. The use of a cement rich in ground granulated blast furnace slag (GGBFS) with a view to stabilizing the chromium is not efficient. Since neither adequate tests nor quality criteria exist to evaluate the pollutant potential of a waste with a view to reusing it, it is difficult to conclude on the environmental soundness of such a practice. Further experiments are necessary to investigate the environmental impact of TFA introduced in cement-based mortars depending on the reuse scenario.

Carbon↗
PubMed2006

Utilization of municipal solid waste incineration (MSWI) fly ash in blended cement Part 1: Processing and characterization of MSWI fly ash.

This paper is the first of a series of two articles dealing with the processes applied to MSWI fly ash with a view to reusing it safely in cement-based materials. Part 1 presents two stabilization processes and Part 2 deals with the use of the two treated fly ashes (TFA) in mortars. Two types of binder were used: an Ordinary Portland Cement (OPC) containing more than 95% clinker (CEM I 52.5R) and a binary blend cement composed of 70% ground granulated blast furnace slag and 30% clinker (CEM III-B 42.5N). In this first part, two stabilization processes are presented: the conventional process, called "A", based on the washing, phosphation and calcination of the ash, and a modified process, called "B", intended to eliminate metallic aluminum and sulfate contained in the ash. The physical, chemical and mineralogical characteristics of the two TFA were comparable. The main differences observed were those expected, i.e. TFA-B was free of metallic aluminum and sulfate. The mineralogical characterization of the two TFAs highlighted the presence of large amounts of a calcium aluminosilicate phase taking two forms, a crystalline form (gehlenite) and an amorphous form. Hydration studies on pastes containing mixed TFA and calcium hydroxide showed that this phase reacted with calcium hydroxide to form calcium aluminate hydrates. This formation of hydrates was accompanied by a hardening of the pastes. These results are very encouraging for the reuse of such TFA in cement-based materials because they can be considered as pozzolanic additions and could advantageously replace a part of the cement in cement-based materials. Finally, leaching tests were carried out to evaluate the environmental impact of the two TFAs. The elements which were less efficiently stabilized by process A were zinc, cadmium and antimony but, when the results of the leaching tests were compared with the thresholds of the European landfill directive, TFA-A could nevertheless be accepted at landfills for non-hazardous waste. The modifications of the process led to a significant reduction in the stabilization of chromium, selenium and antimony.

Aluminum↗
PubMed2005

Cerebral venous sinus thrombosis in children: risk factors, presentation, diagnosis and outcome.

Neuroimaging and management advances require review of indications for excluding cerebral venous sinus (sinovenous) thrombosis (CSVT) in children. Our goals were to examine (i) clinical presentations of CSVT, (ii) prothrombotic risk factors and other predisposing events, (iii) clinical and radiological features of brain lesions in CSVT compared with arterial stroke, and (iv) predictors of outcome. We studied 42 children with CSVT from five European paediatric neurology stroke registries. Patients aged from 3 weeks to 13 (median 5.75) years (27 boys; 64%) presented with lethargy, anorexia, headache, vomiting, seizures, focal signs or coma and with CSVT on neuroimaging. Seventeen had prior chronic conditions; of the 25 previously well patients, 23 had recent infections, eight became dehydrated and six had both. Two children had a history compatible with prior CSVT. Anaemia and/or microcytosis (21 probable iron deficiency, five haemolytic, including two with sickle cell disease and one with beta-thalassaemia) was as common (62%) as prothrombotic disorder (13/21 screened). High factor VIII and homozygosity for the thermolabile methylene tetrahydrofolate reductase polymorphism were the commonest prothrombotic disorders. The superficial venous system was involved in 32 patients, the deep in six, and both in four. Data on the 13 children with bland infarction and the 12 with haemorrhage in the context of CSVT were compared with those from 88 children with ischaemic (AIS) and 24 with haemorrhagic (AHS) arterial stroke. In multiple logistic regression, iron deficiency, parietal infarction and lack of caudate involvement independently predicted CSVT rather than arterial disease. Five patients died, three acutely, one after recurrence and one after 6 months being quadriparetic and blind. Follow-up ranged from 0.5 to 10 (median 1) years. Twenty-six patients (62%) had sequelae: pseudotumour cerebri in 12 and cognitive and/or behavioural disabilities in 14, associated with epilepsy in three, hemiparesis in two and visual problems in two. Eighteen patients, including six with haemorrhage, were anticoagulated. Older age [odds ratio (OR) 1.54, 95% confidence limits (CI) 1.12, 2.13, P = 0.008], lack of parenchymal abnormality (OR 0.17, 95% CI 0.02, 1.56, P = 0.1), anticoagulation (OR 24.2, 95% CI 1.96, 299) and lateral and/or sigmoid sinus involvement (OR 16.2, 95% CI 1.62, 161, P = 0.02) were independent predictors of good cognitive outcome, although the last predicted pseudotumour cerebri. Death was associated with coma at presentation. Of 19 patients with follow-up magnetic resonance (MR) venography, three had persistent occlusion, associated with anaemia and longer prodrome. A low threshold for CT or MR venography in children with acute neurological symptoms is essential. Nutritional deficiencies may be modifiable risk factors. A paediatric anticoagulation trial may be required, after the natural history has been further established from registries of cases with and without treatment.

Adolescent↗
PubMed2004

Metallic aluminum in MSWI fly ash: quantification and influence on the properties of cement-based products.

This article focuses on the effects of metallic aluminum contained in municipal solid waste incineration (MSWI) fly ashes on cement-based materials in which they are added. The ash under study was treated by an industrial physicochemical process of neutralization. The paper also presents a method to quantify the metallic aluminum content of ash: it consists in measuring the amount of hydrogen gas produced by the oxidation reaction of metallic aluminum. This method is simple and fast. Results show that studied ash contains an appreciable amount of metallic aluminum. Investigations were carried out to study the incorporation of the ash in concrete: in this case, the presence of metallic aluminum is worrying because it could be responsible for disorders in concrete. In fact, swellings are observed on cement pastes and mortars containing ash during the first 24 h of hydration. A test based on hydrostatic weighing permits to quantify the swelling of fresh cement paste and to study the evolution of this swelling. Causes of swelling are analyzed. Results show that ettringite formation occurs after the end of the expansion reaction. So it can be concluded that metallic aluminum is the sole responsible for the observed swelling. Consequences of swelling are also analyzed by measuring compressive strength of ash-containing mortars: this swelling leads to cracks in the mortars and significant decrease of their compressive strength.

Aluminum↗
PubMed2004

[Neonatal thrombosis of the jugular veins: long-term repercussions on cerebral development (two cases)].

Bilateral obstruction of the internal jugular veins is rare in the neonatal period and no long-term follow-up has been reported yet. We report two cases. The first developped an extensive thrombosis of superior veina cava related to a central veinous line, the second an unilateral thrombosis of the transverse-sigmoid sinus associated to a constitutional hypoplasia of the contralateral jugular vein. In the latter case, no cause or risk factor was noticeable, except for a forceps delivery. In both cases the clinical course was dominated by the development of a prominent collateral network of cervico-facial veins and by a progressive macrocrania. According to MRImaging, the latter was not related to a dilation of CSF spaces, but to a macro-encephaly, either by inflation of the vascular veinous compartment inside the parenchyma or by genuine brain's overgrowth. Long-term follow-up showed a grossly normal course, both from the neurological and the scholar point of view. However, slight neuropsychological anomalies were noticed, bringing some shade on the prognosis.

Brain↗
PubMed2004

[Pediatric neuroimaging emergencies].

The notion of emergency with regards to pediatric neuroimaging requires a strong knowledge of clinical indications. In children under 2 years of age, head trauma requires a CT scan in case of repeated or prolonged or rapidly increasing vomiting, focal signs, loss of consciousness, unusual behavior, seizures, clinical signs of skull fracture or polytrauma. The "shaken baby syndrome" is usually suspected in case of loss of consciousness or seizures before 8 months of age. The hematomas that are observed are subdural in location, diffuse and deeply located. Imaging is only mandatory for headache suggesting underlying space occupying lesion: permanent or increasing pain, nocturnal headache, headache during postural changes or efforts, associated to seizures or abnormal neurological examination. No imaging is indicated in case of first epileptic seizure associated to normal neurological examination and without any particular context. The presence of trauma, intracranial hypertension, persisting disturbances of consciousness or associated focal sign necessitates urgent neuroimaging. No imaging is indicated in case of typical febrile seizures, i.e. generalized, brief and occurring between 1 and 5 years of age. Spinal cord symptoms require immediate MRI evaluation. The most frequent tumor is neuroblastoma. In the absence of spinal tumor, brain abnormalities must be excluded (inflammatory disease). In neonates, CT scan or MRI must be readily performed in case of seizures or loss of consciousness to exclude ischemic, traumatic or infectious lesions.

Age Factors↗
PubMed2003

[Description and prognostic value of cerebellar MRI lesions in children with severe acute ataxia].

The aim of this work was to evaluate NMR cerebellar abnormalities in children with severe acute ataxia. Among 8 consecutively observed children, NMR performed in 6 during the acute phase was pathological in 4, demonstrating hyperintense signal in the T2-weighed sequences of dentate nuclei (2 cases, associated in 1 with hyperintense signal in the medium cerebellar peduncle) or of the cerebellar cortex associated with cerebellar swelling (2 cases). NMR performed in 7 cases after at least 1 month of evolution showed cerebellar atrophy in 4 cases. After 1 to 6 years of clinical follow-up, 4/8 children had clinical sequellae, including 3 of the 4 children with initially abnormal NMR. Conversely, the 2 patients with initially normal NMR had a good clinical recovery. NMR during the acute phase gives informations on prognosis in patients with severe acute ataxia.

Acute Disease↗
PubMed2002

2-Chloro-2'-deoxyadenosine inhibits DNA repair synthesis and potentiates UVC cytotoxicity in chronic lymphocytic leukemia B lymphocytes.

2-Chloro-2'-deoxyadenosine (CdA) is a deoxyadenosine analogue which targets enzymes involved in DNA synthesis, and hence might interfere with the resynthesis step of DNA repair. We tested this hypothesis in resting B cell chronic lymphocytic leukemia (B-CLL) lymphocytes, after firstly characterizing unscheduled DNA synthesis occurring in these cells. We observed that the spontaneous incorporation of [methyl-3H]thymidine (dThd) into DNA of B-CLL cells was not completely inhibitable by hydroxyurea (HU) which blocks DNA replication. In addition, in the presence of HU, dThd incorporation could be upregulated by UVC radiation or DNA alkylation, without re-entry of the cells into S phase. CdA was found to inhibit both spontaneous and upregulated DNA synthesis in B-CLL cells. Phosphorylation of CdA was essential to exert this effect. We finally observed a strong synergistic cytotoxicity between UV light and CdA, which was correlated with activation of caspase-3 and high molecular weight DNA fragmentation, two markers of apoptosis. Taken together, these observations indicate that in B-CLL cells CdA inhibits unscheduled DNA synthesis which represents the polymerizing step of a repair process responsive to DNA aggression. Inhibition of this process by CdA, together with a combined activation of the apoptotic proteolytic cascade by CdA and UV, may explain their synergistic cytotoxicity.

Alkylating Agents↗
PubMed2000

[Epilepsy presenting as life-threatening events in infants].

OBJECTIVE: This study was aimed at assessing the frequency and features of epilepsy presenting as life-threatening events in infancy. PATIENTS AND METHODS: Fifteen cases were collected over eight years. Subtle symptoms suggestive of epilepsy were rare (9/15) in the retrospective analysis; the clinical context and cerebral imaging were occasionally contributive (5/15); interictal EEG was useful but inconstantly contributive, including when the epileptic nature of the episodes had become clinically probable (10/15). Though it had no clear relationships with epileptic episodes but contributed to mislead diagnosis, gastroesophageal reflux was frequently associated. Uncovered epilepsies were not homogeneous, ranging from severe epileptic encephalopathy to benign epilepsy of infancy. CONCLUSION: Epilepsy presenting as life-threatening events is sometimes a diagnostic challenge. When an infant develops recurrent critical episodes during a several-week follow-up, with neurological and general investigations not providing more information, the immediate success of antiepileptic treatment might support diagnosis.

Critical Illness↗
PubMed2000

Stroke in childhood: outcome and recurrence risk by mechanism in 59 patients.

This paper describes 59 patients, 3 months to 16 years of age, who were seen consecutively in the same center for cerebral arterial infarction. It focuses on the mechanism of stroke. The pathophysiologic process could be established for 78% of the children. Arteriopathic stroke (31 patients, or 53%) was the most common. The arteriopathies were either progressive (moyamoya in 4 patients, or 7%) or nonprogressive (27 patients, or 46%). The latter form occurred in two patterns: dissection of cervicocephalic arteries (12 patients, or 20%) and transient cerebral arteriopathy of unknown origin but probably angiitis (15 patients, or 25%). Cardiac or transcardiac embolic stroke occurred in 12% of the series and systemic diseases in 14%. There was a favorable outcome in 70% of patients having stroke due to nonprogressive arterial disease and stroke due to unidentified mechanisms. In contrast, only 26% of patients with embolic stroke, systemic disease, or moyamoya had a favorable outcome. Recurrences were more frequent and severe in this latter group. It is concluded that it is important to determine the mechanism of childhood stroke, because it strongly influences outcome, the recurrence risk, and treatment choice.

Adolescent↗
PubMed2000

Food intake regulation in rodents: Y5 or Y1 NPY receptors or both?

Neuropeptide Y (NPY), one of the most abundant peptides in rat and human brains, appears to act in the hypothalamus to stimulate feeding. It was first suggested that the NPY Y1 receptor (Y1R) was involved in feeding stimulated by NPY. More recently a novel NPY receptor subtype (Y5R) was identified in rat and human as the NPY feeding receptor subtype. There is, however, no absolute consensus since selective Y1R antagonists also antagonize NPY-induced hyperphagia. Nevertheless, new anti-obesity drugs may emerge from further pharmacological characterization of the NPY receptors and their antagonists. A large panel of Y1R and Y5R antagonists (such as CGP71683A, BIBO3304, BIBP3226, 1229U91, and SYNAPTIC and BANYU derivatives but also patentable in-house-synthesized compounds) have been evaluated through in vitro and in vivo tests in an attempt to establish a predictive relationship between the binding selectivity for human receptors, the potency in isolated organs assays, and the inhibitory effect on food intake in both normal and obese hyperphagic rodents. Although these results do not allow one to conclude on the implication of a single receptor subtype at the molecular level, this approach is crucial for the design of novel NPY receptor antagonists with potential use as anti-obesity drugs and for evaluation of their possible adverse peripheral side effects, such as hypotension.

Animals↗
PubMed1999

Haemorrhagic shock and encephalopathy syndrome: neurological course and predictors of outcome.

UNLABELLED: The haemorrhagic shock and encephalopathy syndrome (HSES) is a devastating disease. The aetiology of this syndrome is unknown, and, despite intensive treatment, the outcome is often fatal or associated with severe neurological sequelae. OBJECTIVE: To assess the neurological features and potential prognostic markers of the disease. DESIGN: Retrospective study. SETTING: Division of Neuropaediatrics in a children's university hospital. PATIENTS AND METHODS: Fourteen patients fulfilling the HSES criteria out of 42 children admitted with fever and shock to the Paediatric Intensive Care Unit between 1986 and 1994, were analysed for clinical, biological, neuroradiological, EEG and neuropathological findings. RESULTS: The patients (age range from 2 to 33 months) were found at night or in the morning either comatous (n = 3) or convulsing (n = 11). All but one were healthy before admission, although eight had had a brief prodromal infectious disease. All were febrile (mean body temperature 39.9 degrees C +/-0.9 degrees). Seasonal clustering during the winter months was observed. Coma and seizures with frequent status epilepticus were the main neurological manifestations. All children recovered from their multiple organ failure within a few days. Seven died (50%); four survivors had neurological sequelae (29%) with a developmental quotient (DQ) of 50% or less in three and a DQ of 75% in one and three infants (21%) had normal outcomes. Computed tomography (CT) displayed a diffuse area of low density mainly in the cerebral cortex and intraventricular and parenchymal haemorrhages. Magnetic resonance imaging (MRI) showed haemorrhagic cortical lesions. Postmortem examination of the brain conducted in three patients showed necrotic and haemorrhagic lesions, mainly in cortical areas. Comparison of the children with adverse outcome (death or neurological sequelae) with those with normal outcome revealed that predictors of poor outcome were status epilepticus (p = 0.003) and coma for more than 24 h (p = 0.01). Infants without disseminated intravascular coagulation, without a biphasic course and without brain hypodensities or haemorrhages on CT scans performed at least 4 days after onset had a normal neurodevelopmental outcome. CONCLUSION: The central nervous system appeared to be the main target of the HSES lesions. The most common outcome was brain death or severe brain damage. Further studies with a larger sample are necessary to determine whether the prognostic indicators we identified are reliable.

Brain↗
PubMed1998

MRI-neuropathological correlations in type 1 lissencephaly.

Although imperfect, MRI is the best way of distinguishing type 1 lissencephaly from other, less classical lissencephalic malformations. We reported a case in which correlation of MRI and neuropathology was possible. Besides the classical radiological features of lissencephaly, i.e., agyria and excessive thickness of the cortex, an additional sign was observed: a thin cortical band, which gave high signal on T2-weighted images, represented a paucicellular and partially myelinated band, 1500 microns thick, lying under the true superficial cortex. This MRI feature could be characteristic of the particular cortical lamination observed in true type 1 lissencephaly.

Cerebral Cortex↗
PubMed1998

Bone marrow transplantation in metachromatic leukodystrophy caused by saposin-B deficiency: a case report with a 3-year follow-up period.

A 2-year-old child had a metachromatic leukodystrophy-variant phenotype mainly involving the peripheral nervous system (PNS) that was caused by saposin-B deficiency. Bone marrow transplantation resulted in transient deterioration then continuous improvement of PNS functions. These findings were supported by nerve conduction velocity measurements, but the symptoms ultimately worsened. Magnetic resonance imaging showed persistent white matter lesions and progressive pontocerebellar atrophy.

Bone Marrow Transplantation↗
PubMed1997

[Central pontine myelinolysis: apropos of 2 case in children].

BACKGROUND: Central pontine myelinolysis has been rarely reported in children. This report concerns two children, aged 4 1/2 years. CASE REPORTS: The main clinical features were altered level of consciousness, tetraplegia and signs of brain stem dysfunctions. In both cases, magnetic resonance imaging (MRI) revealed hypersignal of protuberance in association with cerebellar lesion in one case and occipital lesion in the other, compatible with central and extrapontine myelinolysis. No underlying disease or electrolytic disorders was identified. Clinical outcome was good. Mental status was normal after 9 months for patient one and 4 months for patient two. The MRI abnormality was reduced at 9-month follow-up in patient two and unchanged at 4 months in patient one. CONCLUSION: The incidence of central pontine myelinolysis is probably underestimated in children. MRI allows a greater sensitivity in identifying areas of focal demyelination where diagnosis was previously only established by post mortem studies.

Brain↗
PubMed1997

[Ischemic cerebral vascular accident caused by vertebral artery dissection].

BACKGROUND: Strokes due to vertebral artery lesions are not yet well known in children. CASE REPORT: We report on a case of post-traumatic vertebral artery dissection responsible for ischemic stroke in a 8-year old boy. Headache, vomiting and a brief loss of consciousness were the main initial signs. Neurological examination showed a locked-in syndrome. Cerebral imaging revealed lesions in cortical cerebellar hemisphere, cerebral pedoncular and protuberance. An arteriogram performed on day 10 showed left vertebral artery occlusion at C2 levels consistent with vertebral dissection. Antiagregants treatment was given. Neurological recovery was good. Pertinent clinical data of 24 children who had strokes due to a vertebral artery dissection are analysed. CONCLUSION: Vertebral artery dissection is presently a well-known cause of childhood strokes. Benefits from anticoagulants are now established.

Aortic Dissection↗