Biomedical subjects

Maarten A C Meijssen

Publications and source records attributed to Maarten A C Meijssen.

3 recordsLinked to original sources

PubMed2006

Argon plasma coagulation for radiation proctitis.

BACKGROUND: Rectal blood loss is a common late sequel of radiation proctitis. Teleangiectasias appear in the mucosa in 2-5% of patients after radiotherapy of the pelvis. Since pharmacotherapy is usually not beneficial, local treatment modalities with formalin irrigation, Nd:YAG laser and argon plasma coagulation (APC) have been advocated, but experience is still limited. METHODS: Between January 1997 and August 2001, 50 consecutive patients with rectal bleeding due to radiation proctitis were included for treatment with APC. Thirteen patients suffered from anaemia, six of whom required blood transfusion. Nine patients were receiving anticoagulant therapy and 10 patients used low-dose aspirin. APC was performed, applying the no-touch spotting technique at an electrical power of 50 Watt and an argon gas flow of 2.0 l/min. Pulse duration was less than 0.5 s. Treatment sessions were carried out at intervals of 3 weeks. RESULTS: In 47 out of 48 patients (98%) in whom the effect could be assessed, APC led to persistent clinical and endoscopic remission of rectal bleeding after a median of three sessions. One patient developed recurrent blood loss after resuming anticoagulant therapy for his aortic valve prosthesis. No adverse effects were encountered after initial treatment. One serious complication occurred in a patient with recurrent blood loss when he was prescribed aspirin for a transient ischaemic attack 2 years after the initial APC. Re-treatment resulted in a major rectal bleeding from a small ulcer with a visible vessel. CONCLUSIONS: APC is a safe, effective and well-tolerated treatment for blood loss due to radiation proctitis. The use of anticoagulants and aspirin seems to be a co-factors that induces bleeding.

Aged↗

PubMed2003

Effect of pharmacologically induced smooth muscle activation on permeability in murine colitis.

BACKGROUND: Both intestinal permeability and contractility are altered in inflammatory bowel disease. Little is known about their mutual relation. Therefore, an in vitro organ bath technique was developed to investigate the simultaneous effects of inflammation on permeability and smooth muscle contractility in different segments of the colon. METHODS AND MATERIALS: BALB/c mice were exposed to a 10% dextran sulphate sodium drinking water solution for 7 days to induce a mild colitis, while control mice received normal tap water. Intestinal segments were placed in an oxygenated organ bath containing Krebs buffer. Permeability was measured by the transport of the marker molecules 3H-mannitol and 14C-polyethyleneglycol 4000. Contractility was measured through a pressure sensor. Smooth muscle relaxation was obtained by salbutamol and l-phenylephrine, whereas contraction was achieved by carbachol and 1-(3-chlorophenyl)-biguanide. RESULTS: The intensity of mucosal inflammation increased throughout the colon. Also, regional differences were observed in intestinal permeability. In both normal and inflamed distal colon segments, permeability was diminished compared with proximal colon segments and the non-inflamed ileum. Permeability in inflamed distal colon segments was significantly decreased compared with normal distal segments. Pharmacologically induced relaxation of smooth muscles did not affect this diminished permeability, although an increased motility positively affected permeability in inflamed and non-inflamed distal colon. CONCLUSIONS: Inflammation and permeability is inversely related. The use of pro-kinetics could counteract this disturbed permeability and, in turn, could regulate the disturbed production of inflammatory mediators.

Albuterol↗

PubMed2002

Intestinal blood flow in murine colitis induced with dextran sulfate sodium.

The aim of this study was to assess whether colitis induced by dextran sulfate sodium (DSS; 10% in tap water for 7 days) in BALB/c mice is associated with changes in intestinal blood flow. After anaesthesia, systemic hemodynamic variable and regional blood flows and resistances in various organs were measured in both control and DSS-treated mice. Mean arterial blood pressure was significantly lower in DSS-treated mice than in controls (56 +/- 4 vs 66 +/- 3 mm Hg; P < 0.05), but no differences were found in regional blood flows to or vascular resistances in the lungs, liver, stomach, small intestine (upper, middle, and lower part), cecum, mesentery + pancreas, spleen, kidneys, brain, and skin. However, compared to the control mice, blood flows in the middle (0.88 +/- 0.13 vs 0.55 +/- 0.09 ml/min/g; P < 0.05) and distal (0.69 +/- 0.11 vs 0.29 +/- 0.05 ml/min/g; P < 0.05) colon were significantly higher, and vascular resistances in the proximal (0.87 +/- 0.21 vs 1.36 +/- 0.21 mm Hg min/ml/100 g; P < 0.05), middle (0.60 +/- 0.10 vs 1.46 +/- 0.35 mm Hg min/ml 100 g; P < 0.05) as well as distal (0.90 +/- 0.25 vs 2.67 +/- 0.49 mm Hg min/ml/100 g; P < 0.05) colon were significantly lower in mice with experimental colitis. Interestingly, there was a gradient in the intestinal blood flow in control mice from the upper small intestine (2.79 +/- 0.72 ml/min/g) down to the distal colon (0.29 +/- 0.05 ml/min/g); such a gradient was also present in the colitis mice. It is concluded that DSS-induced colitis in mice is associated with microcirculatory disturbances in the colon, mainly in its middle and distal parts.

Animals↗