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Biomedical subjects

F Christiaens

Publications and source records attributed to F Christiaens.

At least 19 recordsLinked to original sources
PubMed2003

Alterations in human epidermal Langerhans cells by ultraviolet radiation: quantitative and morphological study.

BACKGROUND: Ultraviolet (UV) exposure of human skin induces local and systemic immune suppression. This phenomenon has been well documented when UVB radiation (290-320 nm) is used. The mechanism is thought to involve Langerhans cells (LCs), the epidermal dendritic cells that play a crucial role in antigen presentation. A variety of studies have clearly demonstrated that UVB radiation decreases LC density and alters their morphology and immunological function, but little is known about the effects of the entire UV spectrum (ultraviolet solar simulated radiation, UV-SSR or UVB + UVA) or UVA (320-400 nm) radiation alone. OBJECTIVES: The purpose of this study was to analyse and compare the effects of a single exposure of human volunteers to UV-SSR, total UVA or UVA1 (340-400 nm) in the human epidermal LC density and morphology. METHODS: Immunohistochemistry on epidermal sheets with various antibodies and transmission electron microscopy (TEM) were used. RESULTS: Immunostaining for class II antigen revealed that a single UV-SSR exposure, corresponding to twice the minimal erythemal dose (MED), induced a significant reduction in LC density with only slight morphological alterations of remaining cells. After a single UVA exposure, LC density showed a dose-dependent reduction with a significant effect at 60 J cm(-2) (well above the MED). Moreover, the reduction of LC dendricity was also dose-dependent and significant for doses exceeding 30 J cm(-2). UVA1 radiation was as effective as total UVA for the later endpoint. As demonstrated by TEM, the location of Birbeck granules containing epidermal cells was modified in UVA-exposed areas. They were located in the spinous rather than in the suprabasal layer. In addition, the morphology of these cells was altered. We observed a rounding up of the cell body with a reduction of dendricity. Alterations of mitochondrial membrane and ridges were also seen. CONCLUSIONS: A single exposure of human skin in vivo to UV-SSR, UVA or UVA1 radiation results in different alterations of density and/or morphology of LCs. All these alterations may impair the antigen-presenting function of LCs leading to an alteration of immune response.

Adolescent↗
PubMed2002

Crossed cerebellar diaschisis secondary to refractory frontal seizures in childhood.

We report a girl with refractory partial seizures since 7 years of age, secondary to right frontal cortical dysplasia, who developed MRI and SPECT abnormalities in the contralateral hemicerebellar cortex. These became more marked, leading to left hemicerebellar atrophy. Crossed cerebellar diaschisis has been described mostly in hemispheric stroke and supratentorial tumours, but less often in epilepsy. It is usually a transient phenomenon. This report shows that crossed cerebellar diaschisis can develop within two years of seizure onset and evolve over time.

Atrophy↗
PubMed2001

[Postinfectious hemicerebellitis].

The clinical signs of cerebellitis are usually bilateral and symmetrical. We report the case of a 9-year-old girl who presented with acute hemiataxia and flaccid hemiparesis associated with a lesion in the ipsilateral cerebellar cortex two weeks after a viral upper respiratory tract infection. The clinical outcome was good without treatment. Imaging follow-up showed hemiatrophy of the cerebellar cortex.

Cerebellar Diseases↗
PubMed2000

Connatal Pelizaeus-Merzbacher disease in two girls.

We report the clinical, radiological and electrophysiological signs in two unrelated girls with the connatal form of Pelizaeus-Merzbacher disease (PMD). MRI plays an important role in the diagnosis, demonstrating the virtual absence of myelination. PMD is classically described as an X-linked leukodystrophy. Our two cases reinforce the hypothesis of a possible autosomal recessive transmission of the connatal form of PMD in some families, as recently presented.

Diagnosis, Differential↗
PubMed2000

MRI spectrum of cortical malformations in tuberous sclerosis complex.

The diagnostic and prognostic value of magnetic resonance imaging in the tuberous sclerosis complex has increasingly been recognized. In this paper, we review the presumed pathogenesis of the cerebral dysgenesis seen in this condition in the light of magnetic resonance imaging features of selected patients. In addition to typical findings related to tubers, we show and discuss varied cortical malformations (from simple localized cortical dysplasia to transmantle dysplasia and schizencephaly) similar to those seen in sporadic cerebral dysgenesis. These cases support the hypothesis that the tuberous sclerosis complex focally affects the radial glial-neuronal complex as a basic unit for brain development. Abnormal stem cells would create dysplastic glia and neurons that fail to differentiate, proliferate, migrate and form a normally organized cortex.

Cell Differentiation↗
PubMed2000

Transcranial magnetic stimulation and other evoked potentials in pediatric multiple sclerosis.

In children, multiple sclerosis is rare and has some clinical and paraclinical differences compared with adults. The assessment of corticospinal motor tracts is expected to be relevant because of their frequent early involvement in this disease. Reported are the results of transcranial magnetic stimulation in two children who presented at 12 and 9 years of age with clinically probable and definite multiple sclerosis, respectively. In Patient 1 the excitatory cortical threshold for the upper limbs was abnormally raised. In Patient 2 the latency of the motor-evoked potentials was considerably increased for the right tibialis anterior muscle, with a slowing of the central conduction time. Although these abnormalities may be consistent with central conduction impairment, they may alternatively suggest early axonal damage because irreversible axonal lesions occurring at the onset of the disease have recently been reported. Testing of central motor tracts, in addition to visual, auditory, and somatosensory pathways, therefore appears appropriate in the multimodal assessment of pediatric patients with suspected multiple sclerosis.

Axons↗
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↗
PubMed2000

[Value of brain MR imaging in infants with a severe idiopathic apparent life threatening event].

OBJECTIVE: Prognostic value of a magnetic resonance imaging (MRI) scoring system in infants with a severe apparent life threatening event (ALTE). METHODS: Ten infants with an ALTE (aged between 6 and 31 weeks) were clinically graded according to the PRISM score and evaluated with EEG, evoked potentials and MRI. The 18 MRIs obtained were distributed in 3 classes according to the delay after which they were obtained; class A (n=5): within the first 48 hours after the event, class B (n=7): between day 3 and 8 and class C (n=6): between day 9 and 50. The 18 MRIs were evaluated retrospectively using a scoring system based on 3 categories of lesions: edema, basal ganglia injury and watershed injuries. Five infants died between day 2 and day 15 after the event. The five surviving infants had follow up neurodevelopmental testing after 38 to 77 months. RESULTS: There was no correlation between the 5 MRIs of class A and the neurological outcome. For the MRIs of class B and C, the scoring system can be of great value when combined with the scores of EEG, EP and PRISM. CONCLUSIONS: The scoring system for MRI performed within 48 hours after the event is falsely reassuring. MRI can be helpful as early as 3 days after the event when combined with the score of the electrophysiological investigations and the PRISM.

Basal Ganglia Diseases↗
PubMed1999

Dopey's seizure.

Angelman syndrome is a neurogenetic condition namely characterized by developmental delay, virtual absence of expressive verbal language, peculiar organization of movement, seizures and happy demeanor. This syndrome has been recognized since 1965, but it seems that Walt Disney presented an original depiction of it in his first full-length animated film, including myoclonic jerks and an apparently generalized tonic-clonic seizure.

Angelman Syndrome↗
PubMed1999

Propofol concentrations in follicular fluid during general anaesthesia for transvaginal oocyte retrieval.

Propofol (Diprivan) is an i.v. anaesthetic used for general anaesthesia. The purpose of this study was to measure the propofol concentration in arterial blood and follicular fluid in patients during transvaginal oocyte retrieval. After approval by the University Ethics Committee, 30 women participated in this prospective study. Following induction of anaesthesia with 0.5 mg alfentanil and 2 mg.kg-1 propofol i.v., a continuous infusion of propofol at 10 mg.kg-1.h-1 was used for maintenance of anaesthesia. Follicular fluid and arterial blood samples were aspirated simultaneously at fixed intervals during the surgical procedure and propofol assayed by high pressure liquid chromatography (HPLC). The mean follicular fluid concentration of propofol increased linearly with time from 0.10 +/- 0.02 microgram.ml-1 to 0.57 +/- 0.06 microgram.ml-1 and was strongly related to the cumulative dose of propofol administered. The absorption of propofol was time-dependent. There was no correlation between the concentration of propofol in the follicular fluid and the arterial blood concentration of the drug. In conclusion, a propofol-based anaesthetic technique resulted in significant concentrations of this agent in follicular fluid, related to the dose administered and to the duration of propofol administration.

Adult↗
PubMed1998

Anaesthetic management of a parturient with severe congenital factor XI deficiency undergoing caesarean section for triplet pregnancy.

The report describes the anaesthetic management of a Jewish patient of Ashkenazi descent with severe factor XI deficiency complicated by thrombocytopenia for caesarean section for triplets at the 35th week of gestation. Perioperative management consisted of sustained replacement therapy with fresh frozen plasma and platelets until the sixth postoperative day. General anaesthesia was used for the procedure. No other maternal or neonatal complications occurred.

Journal Article↗
PubMed1998

Comparison of assisted reproductive technology performance after oocyte retrieval under general anaesthesia (propofol) versus paracervical local anaesthetic block: a case-controlled study.

Propofol (Dipirivan) is an intravenous anaesthetic drug used for general anaesthesia. Although frequently used as a general anaesthetic for ultrasound procedures, its use during transvaginal oocyte retrieval is currently being debated. A total of 202 patients undergoing fertility treatment was included in a prospective, matched, controlled study, in which we compared fertilization rates and embryo development in terms of morphological quality and speed of development and the implications for reproductive outcome and pregnancy following general anaesthesia using either propofol or a paracervical local anaesthetic block during oocyte collection. There were no differences between the fertilization rates and the embryo cleavage characteristics for the two groups. The initial implantation rate per transferred embryo after general anaesthesia was similar to that after paracervical local anaesthetic block (13.4 versus 18.6%; P = 0.10). The ongoing clinical implantation rates per embryo transferred were also similar in the two groups.

Adult↗
PubMed1998

Tropisetron for treating established postoperative nausea and vomiting: a randomized, double-blind, placebo-controlled study.

UNLABELLED: Tropisetron can prevent postoperative nausea and vomiting (PONV) at doses smaller than those used to control chemotherapy-induced nausea and vomiting. In this placebo-controlled study, the efficacy and tolerability of three different doses of tropisetron were compared for the treatment of established PONV after surgical procedures in general anesthesia. Of 1513 patients who satisfied inclusion criteria, 314 experiencing PONV during the first 2 h after recovery from anesthesia were treated with one of three different doses of tropisetron (0.5, 2, or 5 mg) or placebo, administered i.v. as a single dose. Patients were then observed during 24 h for efficacy and tolerability. All three doses of tropisetron were significantly better than placebo in controlling emetic episodes and in reducing the need for rescue treatment. There were no significant differences among the three doses. However, in the subgroup of patients who had previous PONV, and in those randomized for nausea alone, the 2-mg and 5-mg doses controlled emetic episodes better than the 0.5-mg dose. All studied doses of tropisetron were well tolerated and did not affect vital signs. We conclude that a single i.v. administration of tropiestron significantly reduces the recurrence of emetic episodes in patients with established PONV after elective surgery with general anesthesia. Its optimal dose seems to be 2 mg. IMPLICATIONS: Three hundred-fourteen patients suffering from postoperative nausea and vomiting received different i.v. doses of a new antiemetic drug, tropisetron, to determine the lowest effective dose. We found that a single i.v. administration of tropisetron significantly reduced postoperative nausea and vomiting after elective surgery with general anesthesia.

Abdomen↗