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Biomedical subjects

M de Vos

Publications and source records attributed to M de Vos.

9 recordsLinked to original sources

Phenotype associated with recessively inherited mutations in DNA mismatch repair (MMR) genes.

The MMR (DNA mismatch repair) system helps to maintain the integrity of the genome. This involves eliminating base-base mismatches and insertion/deletion loops, which can lead to microsatellite instability, as seen in tumour cells. Hereditary non-polyposis colon cancer is the result of dominant mutations in MMR genes, such as MLH1, MSH2 and MSH6. More recently there have been case reports of biallelic mutations in the MMR genes MLH1, MSH2 and PMS2. These result in a distinct autosomal recessive cancer predisposition syndrome. The syndrome is characterized by childhood haematological malignancies, brain tumours and the presence of café au lait patches. Second primaries occur frequently in this condition, and survival into adulthood is rare.

Adenosine Triphosphatases↗

Influence of low-dose oral contraceptives, alcohol, and grapefruit on.

The aminopryine breath test (ABT) measures hepatic reserve in patients with acute and chronic liver disease and gives an assesment of the hepatic function in patients undergoing major liver surgery. Aminopyrine is metabolized by the mixed cytochrome P-450 system, which can be influenced by many foreign compounds and drugs. Whether these foreign compounds and drugs can influence the results of the ABT has seldomly been tested. We studied three groups: Healthy female volunteers, either normally menstruating or taking oral contraceptives, were asked to perform a [13C]ABT during the time of the menses and at midcylce. Healthy volunteers were asked to perform a ABT after consuming 30 g of alcohol. Healthy volunteers were asked to perform a ABT after consuming 250 ml of grapefruit juice. The 13C/12C ratio in expired air was measured by gas isotope ratio mass spectrometry.

Acute Disease↗

Ileocolonoscopic findings in seronegative spondylarthropathies.

Ileocolonoscopy with biopsy of caecum, ileocaecal valve and terminal ileum were performed on 232 patients with seronegative spondylarthropathies and on 65 control patients. Inflammatory gut lesions were found in 65% of the patients with reactive arthritis (ReA) and in 57% of the patients with ankylosing spondylitis (AS), especially in those with peripheral arthritis. The controls had a normal gut. This finding would suggest that exogenous factors causing inflammation of the gut lead to a disturbed permeability of the gut wall or to a deficient local immunological defence mechanism permitting antigens to enter the circulation, inducing the joint and tendon inflammation. Support for this hypothesis was provided by the results of a repeat ileocolonoscopy, disclosing a strong association between the presence of gut inflammation on biopsy and the persistence of joint inflammation. Patients presenting some of the histological lesions found on biopsy (especially active chronic lesions) and patients with proven Crohn's disease were found to share a genetic marker (HLA-BW62). This would suggest that some of the patients with seronegative spondylarthropathies suffer from a subclinical form of Crohn's disease of which the joint symptoms are the unique clinical manifestation.

Adult↗

Detection of antibodies against lipopolysaccharides of Escherichia coli and Salmonella R and S strains by immunoblotting.

Antisera raised against several smooth and rough strains of Escherichia coli and Salmonella typhimurium were tested against lipopolysaccharides (LPS) of homologous and heterologous strains. The LPS were separated by sodium dodecyl sulfate-gel electrophoresis, transferred to nitrocellulose paper, and overlaid with antisera. The results showed that antisera raised against smooth strains reacted with high- as well as low-molecular-weight bands of their corresponding LPS and showed very few cross-reactions. Anti-E. coli J5 antiserum cross-reacted with few strains in the core region. But, anti-S. typhimurium Ra antiserum cross-reacted with many more strains. When these sera were absorbed with either the homologous- or a heterologous-positive strain, reactions were abolished. It appears that reactions of anti-E. coli J5 antiserum and anti-S. typhimurium Ra antiserum with homologous and heterologous strains were not due to the same antibody. This immunoblotting technique proved to be a useful method to distinguish different antibodies in antiserum raised against LPS of gram-negative bacteria.

Animals↗

Allergic granulomatous angiitis.

A 15-year-old boy died after a 3 years' illness; asthmatic bronchitis, recurrent heart failure and eosinophilia were the essential manifestations. The autopsy elicited a diagnosis of allergic granulomatous angiitis, because of angiitis with fibrinoid necrosis and granulomatous lesions in vascular and extravascular regions. The most important differential diagnostic aspects of this disease are discussed, especially the resemblances to Wegener's granulomatosis, hypersensitivity angiitis and polyarteritis nodosa.

Adolescent↗