Search PubMed⌕ Search

Biomedical subjects

N Blanckaert

Publications and source records attributed to N Blanckaert.

80 records · Page 5Linked to original sources
PubMed1976

Mass spectral study of derivatives of the four bilirubin-IX isomers.

The beta, gamma and delta isomers of bilirubin-IX show a decreased stability as compared with the IXalpha isomer; characteristic mass spectra are obtained only for the tetrakis-(trimethylsilyl) derivatives of the IXalpha and IXgamma isomers. Hydrogenation of the vinyl substituents increases the thermal stability of the bilirubins and gives rise to a characteristic mass spectrum for the tetrakis-(trimethylsilyl) derivative of meso-bilirubin-IXdelta. The ethyl anthranilate azopigments derived from the four bilirubins yield characteristic mass spectra, except for the two unstable divinyl substituted azodipyrroles (mol. wt. 416), derived from bilirubin-IXbeta and IXdelta. The corresponding mol. wt. 420 azopigments derived from the hydrogenated bilirubins are thermally stable. Elucidation of mass spectral fragmentation pathways is facilitated by the varying positions of the substituents and by deuterium labelling, and permits the assignment of structures to the various isomeric azodipyrroles.

Azo Compounds↗
PubMedDate not supplied

Analysis of bilirubins in biological fluids by extraction and thin-layer chromatography of the intact tetrapyrroles: application to bile of patients with Gilbert's syndrome, hemolysis, or cholelithiasis.

A method was developed to extract quantitatively the bilirubins from bile, urine, serum, stool, and preparations from liver with a chloroform-ethanol mixture at pH 1.8 in the presence of ascorbic acid and NaCl. Extracted pigment was submitted to thin-layer chromatography, and the separated bilirubins were either immediately eluted and determined spectrophotometrically or individually converted to ethyl anthranilate azo derivatives for thin-layer chromatographic analysis of each isolated pigment band. Bilirubins in duodenal bile of eight healthy adults comprised 1.5 +/- 1.3% unconjugated bilirubin-IX alpha, 69 +/- 6% bilirubin diglucuronide, and 16 +/- 4% bilirubin monoglucuronides. Mixed diconjugates containing one glucuronosyl moiety and either one xylosyl or one glucosyl group amounted to 10 +/- 3%. Most samples (6 of 8) contained trace amounts (0.6 +/- 0.6%) of unconjugated bilirubin-IX beta, in agreement with nearly exclusive cleavage of heme at the alpha-meso position. The composition of the bilirubins in bile was normal in 6 patients with cholesterol gallstones, 4 with chronic hepatitis, and 3 with hemolysis. In duodenal bile of individuals with Gilbert's syndrome (n = 10), the concentration of bilirubin conjugates was comparable to that in healthy adults, but the proportion of bilirubin diglucuronides (52 +/- 8%) was decreased. The concentration of unconjugated bilirubin-IX alpha showed a fair positive correlation with that of bilirubin monoglucuronide and was increased in half of the patients with Gilbert's syndrome.

Bile↗
PubMedDate not supplied

Serum bilirubins in hepatobiliary disease: comparison with other liver function tests and changes in the postobstructive period.

Unconjugated bilirubin and its mono- and diester conjugates were measured by alkaline methanolysis and normal-phase high-performance liquid chromatography (AMHPLC) in 195 serum specimens obtained from 63 patients with various hepatobiliary disorders and from 47 healthy adult controls. With this assay, esterified bilirubins were undetectable in the controls, and detection of esterified pigment in a sample was interpreted as an abnormal result. Using this criterion, the AMHPLC result in the clinical anicteric patients (n = 39) was more frequently abnormal (87%) than the corresponding value of fasting serum bile acids (48%), SGPT (52%), total bilirubins (55%), alkaline phosphatase (71%) or gamma-glutamyl transpeptidase (71%). The cumulative frequency of abnormality of these tests was comparable to that of an abnormal AMHPLC result alone. All icteric patients had detectable esterified bilirubins as well as an increased alkaline phosphatase level, while a normal result was found for serum bile acids in 34%, for SGPT in 29% and for gamma-glutamyl transpeptidase in 11%, respectively. In most hyperbilirubinemic patients, total serum bilirubin levels, as determined by a conventional diazo method, exceeded the value obtained by AMHPLC. This discrepancy, which appears to reflect the presence of bilirubin covalently bound to serum protein, was particularly pronounced following desobstructive intervention in patients with obstructive jaundice, in whom the decline of serum bilirubins showed a fast and a slow disappearance component. The latter portion seemed to correspond with slow plasma clearance of bilirubin covalently linked to serum albumin, disappearing at a rate comparable to that of the albumin moiety.

Adolescent↗
PubMedDate not supplied

Serum tissue polypeptide antigen (TPA): monoclonal or polyclonal radio-immunometric assay for the follow-up of bladder cancer.

Tissue polypeptide antigen (TPA) is a serological tumor marker, measuring cytokeratin 8, 18 and 19, used in the follow-up of non squamous epithelium- and derived neoplasms. It has been demonstrated that TPA is reliable in the monitoring of the efficacy of a curative or palliative treatment of bladder cancer. Recently, a monoclonal antibody-based assay for TPA (TPA-M) has been developed, which seems to be equivalent to the polyclonal-based assay. The aim of the study was to assess the superiority of the monoclonal to the polyclonal test in patients with bladder carcinoma. The value of tissue polypeptide antigen was therefore measured both with TPA and TPA-M IRMA. A correlation coefficient of 0.96 was obtained. Precision testing showed a lower overall variability of TPA-M. Since both tests correlate well and TPA-M testing is more precise, faster and easy to perform, we conclude a superiority of TPA-M and advise the monoclonal test as best suited for clinical use in the follow-up of bladder cancer patients with poorly differentiated superficial, locally advanced or systemic disease after curative or palliative therapy.

Antibodies↗
PubMedDate not supplied

Serum tissue polypeptide antigen (TPA) as tumor marker for bladder cancer.

Tissue polypeptide antigen is a differentiation and proliferation marker of non-squamous epithelium and derived neoplasms. No reliable tumor markers are available for bladder cancer. The value of tissue polypeptide antigen was therefore prospectively investigated. The serum tissue polypeptide antigen samples were obtained from 144 newly diagnosed transitional cell carcinoma patients and from 92 patients that were followed after treatment. The normal cut off value was defined at 95 units per liter. Nearly all TaT1 patients had normal TPA values, and 80% of the muscle invasive cancers had normal TPA levels. In those patients where TPA was elevated before treatment its monitoring proved to be a reliable predictor of tumor progression. Tissue polypeptide antigen is a useful marker not for the early detection of bladder cancer but for the monitoring of the efficacy of a treatment.

Biomarkers, Tumor↗