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Biomedical subjects

B Wouters

Publications and source records attributed to B Wouters.

17 recordsLinked to original sources
PubMed2003

Non-invasive 19F MR spectroscopy of 5-fluorocytosine to 5-fluorouracil conversion by recombinant Salmonella in tumours.

The aim of this study was to evaluate the applicability of fluorine-19 magnetic resonance spectroscopy ((19)F MRS) for monitoring in vivo the conversion of 5-fluorocytosine (5-FC) to 5-fluorouracil (5-FU) after using an attenuated Salmonella Typhimurium strain recombinant to provide cytosine deaminase (TAPET-CD). The (19)F MRS measurements were done on mice bearing the human colon tumour xenograft (HCT116). The intratumoural conversion is greater when TAPET-CD/5-FC is delivered intratumourally (i.tu.) than when TAPET-CD is delivered intravenously (i.v.) and 5-FC intraperitoneally (i.p.). Repeat measurements of the same tumour also yielded important information on the tumour colonization by TAPET-CD through the correlated 5-FC to 5-FU conversion efficacy. The in vivo MRS spectra were confirmed by in vitro (19)F MRS of perchloric acid extracts of the tumour tissue. No 5-FU metabolites were detectable in vivo in the tumours. However, the in vitro measurements revealed, besides 5-FC and 5-FU, the presence of small amounts of catabolites. Finally, spectra obtained in vitro from liver extracts of tumour-bearing mice treated i.tu. with TAPET-CD/5-FC showed no 5-FU and only little amounts of catabolites. Our data illustrate most importantly the potential of (19)F MRS to monitor biologically-based treatments involving cytosine deaminase.

Animals↗
PubMed2003

Tumor-specific gene delivery using genetically engineered bacteria.

The loco-regional control of cancer remains a major contributor to the treatment outcome for many cancer patients prescribed conventional radiotherapy or chemotherapy. Failure of treatment coupled with the realisation that cancer is essentially a genetic disease has led to development of many clinical protocols based on gene therapy. In this review, we will describe an alternative gene delivery system based on the use of non-pathogenic bacteria. Tumor regressions have been reported long ago in patients with bacterially infected tumors, suggesting that bacteria could target tumors and have local anti-tumor effects. The basis of this phenomenon is attributable to the unique properties of the tumor micro-environment. The presence of hypoxic and/or necrotic areas provides a haven for a number of anaerobic bacteria and over the past 60 years, several strains of anaerobic bacteria have been shown to localise within and cause cell lysis of experimental animal tumors. One of the most important strains in that context is Clostridium. Other bacteria have also been implicated in experimental anti-cancer settings. Of these, attenuated Salmonella strains capable of both selective amplification within tumors and expression of effector genes encoding therapeutic proteins are probably the most promising. We will discuss the potential advantages and the pitfalls of this alternative delivery approach. We will emphasize the importance of hypoxia in solid tumors and discuss the potential of radiation-inducible promoters and combined treatment modalities, involving vascular targeting and radiotherapy. We believe that this approach will act in a complementary way to current radiotherapy and chemotherapy treatments of solid tumors.

Animals↗
PubMed1992

Endoscopic treatment of the hypopharyngeal (Zenker's) diverticulum.

Over the years the techniques for endoscopic treatment of Zenker's diverticulum have been improved. Initially, in 1964, we used the electrocoagulation technique as described by Dohlman, but currently we prefer to sever the tissue bridge between the diverticulum and esophagus with the CO2 laser under microscopic control. The results of endoscopic treatment in 507 patients with a diverticulum are discussed. It is concluded that endoscopic treatment can readily be performed with good results, especially in the case of elderly patients in a poor general condition.

Adult↗
PubMed1991

Late onset asthma?

A 77 yr old male was referred for dyspnoea and recurrent infections of the lower airways for the previous five months. On the lateral chest roentgenogram a process in the tracheal area was found, and during bronchoscopy a polypoid tumour was seen about four centimetres above the main carina. It appeared to be a benign endotracheal tumour which was removed after coagulation by a Neodymium yttrium aluminium garnet (YAG) laser.

Age Factors↗
PubMed1990

Amyloid tumour resected by laser therapy.

We report a patient presenting with dyspnoea, cough and fever with a middle lobe atelectasis. Amyloid deposits in the bronchial wall caused almost complete obstruction of the middle lobe bronchus. The patient was treated with neodymium yttrium aluminium garnet (NdYAG) laser photoresection resulting in complete clearance of the middle lobe bronchus. Laser therapy has to be considered as first-line therapy for patients with endobronchial amyloidosis.

Adult↗
PubMed1989

[Stridor in children].

Stridor is the presenting symptom of abnormalities of larynx and trachea in children. The anatomical differences in size and consistency of the larynx play a crucial role in stridor in children as compared with adults. From 1983 to 1988, 81 children (65 males, 16 females) with severe or prolonged stridor were admitted to our hospital. Thorough examination, including endoscopy of larynx and trachea and radiology revealed various congenital abnormalities and acquired conditions as the cause of stridor. Congenital laryngeal anomalies accounted for stridor in 26 children, there were 12 children with congenital tracheal or vascular anomalies, 28 with infectious diseases and 15 with other diseases. Intubation and (or) tracheotomy were performed in one-third of the patients: 5 of them died of severe complications. For proper treatment of children with stridor it is essential to investigate its aetiology carefully.

Child↗
PubMed1989

Laser surgery in lingual tonsil hyperplasia.

Modern techniques have reduced the long existing reluctance to perform lingual tonsillectomy. The results of treatment of hyperplasia of the lingual tonsil with the carbon dioxide laser in 32 patients are presented. After exposure with a special endoscope the lingual tonsil can be vaporized or excised under microscopic control with promising results, far superior to the results obtained with other surgical techniques. Since the success rate of the surgery depends on the diagnostic criteria for applying this therapy, a careful selection of patients is essential.

Adult↗
PubMed1989

Dextrocardia?

Explore the source record for details and available documents.

Adolescent↗
PubMedDate not supplied

A comparison of amodiaquine and sulfadoxine-pyrimethamine as first-line treatment of falciparum malaria in Kenya.

A randomized 14-day study in vivo compared the response of Plasmodium falciparum malaria to amodiaquine (35 mg/kg) and sulfadoxine-pyrimethamine (sulfadoxine, 25 mg/kg) in symptomatic outpatients at 2 sites in northern and western Kenya during 1993. Of the 239 patients recruited, 181 (76%) completed the study [84 (46%) on amodiaquine and 97 (54%) on sulfadoxine-pyrimethamine]. There were no significant differences in the parasitological, clinical or haematological responses between the 2 drug groups in both areas, with 18.5% resistance to amodiaquine versus 9.5% for sulfadoxine-pyrimethamine in the north and 35.1% against amodiaquine versus 34.5% for sulfadoxine-pyrimethamine in the west. In both sites defervescence was significantly more rapid with amodiaquine (P < 0.05) and true clinical failure (symptomatic illness with recurrent parasitaemia) was unusual (9%). As high-level resistance to chloroquine is widespread, both drugs are valuable alternatives. However, the significantly higher levels of resistance in the west may be a sign of the increased drug pressure in this holoendemic area and send an important warning concerning resistance to sulfadoxine-pyrimethamine.

Amodiaquine↗
PubMedDate not supplied

Pathogenesis and endoscopic treatment of the hypopharyngeal (Zenker's) diverticulum.

The authors review the literature about the pathogenesis -still unknown- of Zenker's diverticulum as well as their experience of endoscopic treatment of this disease. From 1964 till 1988, they have treated endoscopically 507 patients, 323 by electrocoagulation, 184 by CO2-laser. The endoscopic procedure is described, consisting in precise division of the tissue bridge between the oesophagus and the diverticulum by micro-endoscopic surgery under general anesthesia. In recent years, the CO2-laser was found preferable, since it may cause less tissue necrosis and consequently less fibrous scar tissue. The results were very favourable, with more than 99% of the patients satisfied. Although many patients were old and in poor condition, only one patient died two days after operation because of cardiac failure. Complications such as bleeding, emphysema, mediastinitis and stenosis were seen in 5% of the patients, but in most cases there complications were mild and conservative therapy was sufficient. Stenosis occurred in 8 patients treated by electrocoagulation and in none of the patients treated by laser. Microendoscopic surgery is a safe and efficient method of therapy for the hypopharyngeal diverticulum.

Adult↗