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R Van de Velde

Publications and source records attributed to R Van de Velde.

12 recordsLinked to original sources
PubMed2000

Framework for a clinical information system.

The current status of our work towards the design and implementation of a reference architecture for a Clinical Information System is presented. This architecture has been developed and implemented based on components following a strong underlying conceptual and technological model. Common Object Request Broker and n-tier technology featuring centralised and departmental clinical information systems as the back-end store for all clinical data are used. Servers located in the 'middle' tier apply the clinical (business) model and application rules to communicate with so-called 'thin client' workstations. The main characteristics are the focus on modelling and reuse of both data and business logic as there is a shift away from data and functional modelling towards object modelling. Scalability as well as adaptability to constantly changing requirements via component driven computing are the main reasons for that approach.

Appointments and Schedules↗
PubMed1997

Towards a component driven infrastructure for integrated healthcare systems.

A high level summarised description of the distributed clinical information system implemented in the hospital of the free university of Brussels (AZ-VUB) is described. It evolves towards a component based clinical distributed system that consists of a set of co-operating middelware software components running on a number of computers connected by a network that will foster the integration of applications, data servers and other resources in the medical field. This system is implemented in the University Hospital of Brussels (AZ-VUB) a full-service 800-bed university hospital that provides care for 23,000 inpatients, supports over 300,000 outpatient visits and receives 32,000 emergency patients a year.

Belgium↗
PubMed1994

Chemiluminescent detection of Fiji disease virus with biotinylated DNA probes.

Biotinylated Fiji disease fijivirus specific cDNA probes detected the presence of the virus in total nucleic acid extracts from infected sugarcane plants. Hybridised biotinylated probes were detected with streptavidin-alkaline phosphatase conjugate and the light generating substrate AMPPD. Samples were either blotted manually, or by alkaline capillary transfer using 100 mM NaOH. Transfer of nucleic acids to charge modified nylon with sodium hydroxide was superior to denaturation with glyoxal or formamide and salt-citrate buffer transfer as the bands were clearly resolved and no degradation of the FDV dsRNA was observed. Transfer of either total nucleic acid extracts or purified dsRNA in manifold blots generated false positive signals with the non-radio-active chemiluminescent detection systems tested. Manual or northern blots had a limit of detection for purified target double-stranded RNA of approximately 10 pg and 0.5 pg respectively. Manual blots were tested for practical application to screen germplasma for FDV infection. The virus was detected in leaf samples from FDV-infected plants, in some instances prior to development of the characteristic gall symptom.

Biotin↗
PubMed1992

PCR amplification of a specific double-stranded RNA region of Fiji disease virus from diseased sugarcane.

A 450-bp region from one species of the segmented dsRNA genome of Fiji disease virus (FDV) was amplified from total nucleic acid extracts of diseased plants by reverse transcription with MMLV, followed by amplification with Taq DNA polymerase (RT-PCR). Other FDV-specific regions (c 150 bp and c 270 bp) were also amplified from the dsRNA template. FDV cDNA was only synthesised when the viral dsRNA template was boiled and quenched with FDV-specific or random hexamer primers. The reverse transcriptase/DNA polymerase enzyme rTth appeared to yield only the 150 bp fragment from the dsRNA template under the conditions used. The level of sensitivity of RT-PCR for purified FDV dsRNA was 100 ag, approximately 10(4)-fold more sensitive than detection with biotinylated DNA probe.

Base Sequence↗
PubMed1989

Immunopathology of interstitial cystitis.

This study describes histologic, ultrastructural, and immunofluorescence microscopy findings of cystoscopically directed biopsies of lesional tissue and uninvolved bladder from 308 patients with chronic interstitial cystitis (IC) and no evidence of infection, collagen vascular, or other systemic disease. The majority of cases exhibited strong urothelial cell staining for immunoglobulin A (IgA), which was focal or diffusely involved all layers of the epithelium. Electron microscopy revealed widening of the interstitium between urothelial cells, which may explain leakage of IgA into the urine in cystitis patients. Staining for fibrinogen and IgA was present both in lesional biopsies and uninvolved bladder tissue, suggesting a response to injury affecting the entire bladder urothelium. A minor patient population with idiopathic IC revealed granular IgM (with or without C3) in vessel walls of the lamina propria, suggesting immune complex disease. Ultrastructural evidence of vascular damage included necrosis of endothelial cells, fibrin deposition, and reduplication of basement membranes. Staining for IgE correlated with presence of mast cells and was present in less than 2% of cases, indicating that these cells do not play a prominent role in the pathogenesis of the disease. In the majority of patients with IC mucosal staining for IgA and fibrinogen was a characteristic pattern representing increased IgA secretion and a reaction pattern to injury of unknown cause. A subgroup of patients had evidence of vascular damage and immune complex disease. This study therefore defines two main reaction patterns in interstitial cystitis, which may have implications on prognosis and therapy of the disorder.

Adult↗
PubMed1984

Presynaptic serotonin receptors regulate the release of 3H-serotonin in hypothalamic slices of the rabbit.

Hypothalamic slices of the rabbit brain were incubated with 10(-7) M of 3H-serotonin (3H-5HT). After the incubation and an initial washout period, a nearly constant basal efflux of tritium was detected. This basal efflux was not significantly altered by Ca2+-free solution or by the 5HT-antagonist metitepin (10(-5) M), but was augmented by chlorimipramine (10(-5) M) and by unlabelled 5HT (10(-6) M); the acceleration caused by unlabelled 5HT was absent in presence of chlorimipramine (10(-5) M). Both electrical stimulation (4 Hz, 50 mA, 2 min) and high K+ (50 mM) induced an overflow of 3H. This overflow was nearly abolished in Ca2+-free solution. In presence of chlorimipramine (10(-5) M) both the tritium overflow evoked by electrical stimulation and that evoked by high K+ were augmented by metitepin (10(-5) M) and decreased in a concentration dependent manner by unlabelled serotonin (10(-8) - 10(-6) M); the latter effect was antagonized by metitepin (10(-6) M and 10(-5) M). These experiments suggest that in rabbit hypothalamic slices, the release of 3H-5HT is controlled by a negative feedback mechanism acting via presynaptic serotonin receptors.

Animals↗
PubMed1981

Occult medullary carcinoma of thyroid: an unusual clinical and pathologic presentation.

High calcitonin levels noted on a totally healthy 49-year-old man participating in a calcitonin control project led to a presumptive diagnosis of medullary carcinoma. Complete thyroid studies augmented by selective catheterization and quantitative calcitonin studies confirmed the clinical impression of medullary carcinoma. Surgery was recommended and a total thyroidectomy was performed. On gross examination no nodules or tumefactions were palpable. Histopathology showed diffuse C-cell hyperplasia in the midst of which a C-cell tumor and micromedullary carcinoma of the thyroid were found. Morphologically the full spectrum of changes from focal C-cell hyperplasia through the stages of diffuse and nodular hyperplasia to the final development of medullary carcinoma are demonstrated by light and electron microscopy. The patient's postoperative course was benign and for the subsequent three years he had continued asymptomatic with normal calcitonin levels.

Calcitonin↗
PubMed1976

Prenatal diagnosis of placental steroid sulfatase deficiency.

Placental steroid sulfatase deficiency is an unusual cause of low estriol production during pregnancy. Its importance lies in the differentiation of this disorder from the more ominous fetal defects that result in low estriol levels. Serum free estriol levels were found to be low or absent in a 25-year-old gravida 3, para 2 woman, while placental lactogen and chorionic gonadotropin levels were normal. An abdominal x-ray revealed no apparent congenital abnormalities and an oxytocin challenge test was negative. The dehydroepiandrosterone sulfate (DHEA-S) level in the patient's amniotic fluid was 6.8 to 18.4 times greater than those found in control amniotic fluids. The patient's amniotic fluid cortisol level was normal. Twenty-four hours following a normal, spontaneous labor and delivery at 39 weeks, the male infant underwent a synthetic ACTH1-24 stimulation test, with serum cortisols rising from 3.7 to 46 mug/dl at 1 hour. The placenta was morphologically normal on gross, light, and electron microscopic examinations. Steroid 3-alcohol sulfatase and arylsulfatase activities in the patient's placenta were virtually absent. These data indicate that this benign cause of low serum estriol levels may be diagnosed prenatally by elevated amniotic fluid DHEA-S levels.

Adult↗
PubMedDate not supplied

Optimal conditions for the use of cDNA probes to measure the concentration of barley yellow dwarf virus in barley (Hordeum vulgare).

Experiments which optimise the conditions for the measurement of the relative concentration of BYDV in barley (Hordeum vulgare) tissues using cDNA probes are described herein. These studies have shown that both the pH of the buffer and the ratio of buffer to tissue used to homogenise plant material greatly affects the amount of cDNA probe which hybridises to leaf extracts immobilised on nitrocellulose. These studies also showed that the measurement of this virus was greatly facilitated by using a dot-blot apparatus which allows samples contact with a piece of nitrocellulose 10 mm in diameter rather than a 3 mm (approx) diameter piece of nitrocellulose as is the case with most commercial dot-blot apparatuses. Further experiments using this technique showed that there was a large difference in the rate of replication of the PAV, BYDV serotype between BYDV-resistant and BYDV-susceptible cultivars of barley. These data suggest that a BYDV-resistant cultivar can easily be distinguished from a BYDV-susceptible one if the BYDV content of leaves is measured between 7 and 14 days after inoculation.

Buffers↗