Biomedical subjects

A M Stapleton

Publications and source records attributed to A M Stapleton.

24 records · Page 2Linked to original sources

PubMed1995

Blood coagulation proteins and urolithiasis are linked: crystal matrix protein is the F1 activation peptide of human prothrombin.

OBJECTIVES: To determine the relationship between prothrombin and crystal matrix protein (CMP). CMP is the predominant protein found in the organic matrix of calcium oxalate (CaOx) crystals generated from human urine and is a 31 kDa glycoprotein, whose N-terminal amino acid sequence shares homology with human prothrombin. MATERIALS AND METHODS: CaOx crystallization was induced in ultrafiltered (UF) human urine containing either plasma or serum derived from the same healthy donor, by the addition of sodium oxalate. The crystals were demineralized and the resulting protein extracts analysed by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting, using antibodies raised against human prothrombin and the C-terminus of prothrombin fragment 1 + 2 (F1 + 2). RESULTS: Prothrombin was detected in extracts of crystals precipitated from the UF urine in the presence of plasma, while CMP was completely absent. Crystals precipitated from UF urine supplemented with serum contained relatively large amounts of F1 + 2 and a protein with the same electrophoretic mobility as CMP. Analysis of a standard preparation of F1 + 2 which also contained prothrombin fragment 1 (F1) as a minor contaminant, showed a protein with electrophoretic and staining properties comparable to CMP. CONCLUSION: CMP is a urinary form of F1, a degradation product of prothrombin possessing the domain rich in gamma-carboxyglutamic acid, which may have undergone some molecular modification either before or after its release into the urine.

Adult↗

PubMed1995

Association of p53 mutations with metastatic prostate cancer.

In prostate cancer, mutation of the p53 tumor suppressor gene has been associated with locally advanced disease and hormone-resistant disease that is predominantly localized to bone. However, little is known regarding the status of the p53 gene in metastatic prostate cancer that has not been treated with hormonal manipulation. We evaluated formalin-fixed, paraffin-embedded malignant tissues from 86 patients with various stages of prostate cancer, including pathologically confined, locally advanced, and metastatic disease, to detect abnormal p53 nuclear protein accumulation using immunohistochemistry. No abnormal p53 immunostaining was detected in 18 patients with prostate cancer confined to the gland. Two tumors from 21 patients with locally advanced disease (extracapsular extension and/or seminal vesicle invasion) had abnormal nuclear p53 accumulation, and a mutation in exon 7 of the p53 gene was detected in tumor DNA from one patient using single-strand conformation polymorphism-direct sequencing analysis. Of the remaining 47 patients studied in whom tissues from the prostate gland and a metastatic site (44 lymph node, 2 bone, and 1 lung) were available, only 3 had received hormonal therapy prior to obtaining metastatic tissue. In four patients both primary and metastatic tumors demonstrated accumulation of p53 protein, whereas seven additional patients exhibited p53 accumulation only at the metastatic site. In three patients the metastatic tumors harbored missense single-base substitutions in exon 5, as detected using single-strand conformation polymorphism-direct sequencing. These results indicate that p53 abnormalities are associated with lymph node metastases derived from prostate cancer patients that had not undergone hormonal therapy.

Adenocarcinoma↗

PubMed1994

Crystal matrix protein--getting blood out of a stone.

The short history of crystal matrix protein began in 1991, when it was shown to be the predominant protein present in the organic extract of calcium oxalate crystals precipitated from fresh human urine. Here, we review what has subsequently come to be known about the protein, from its highly specific immunohistochemical distribution in the human nephron, to its finding in kidney stones, to the discovery of its relationship with the human blood coagulation zymogen prothrombin, and, finally, its identification as a urinary form of prothrombin activation fragment 1. A vitamin K-dependent glycopeptide, fragment 1 possesses the so-called GLA domain of its parent molecule; its known properties suggest that it may fulfil a determinant role in calcium oxalate urolithiasis as a potent urinary inhibitor of crystal growth and aggregation.

Animals↗

PubMed1993

Crystal matrix protein is related to human prothrombin.

Crystal matrix protein (CMP) is the principal protein found in calcium oxalate (CaOx) crystals precipitated from whole human urine. It is a potent inhibitor of crystal aggregation and may therefore be important in the aetiology of kidney stone disease. CMP was isolated from CaOx crystals by EDTA dissolution and purified by Sephacryl S-200 column chromatography and reversed-phase high pressure liquid chromatography. Edman degradation revealed 81.8% sequence identity of the 11 N-terminal amino acids of CMP with the N-terminus of human prothrombin, which contains 10 gamma-carboxyglutamic acid residues in the first 32 amino acids. The apparent relationship between CMP and prothrombin was confirmed when an antibody to human prothrombin reacted with CMP upon Western blotting of sodium dodecyl sulphate polyacrylamide gels of the protein.

Amino Acid Sequence↗

PubMed1993

Immunohistochemical distribution and quantification of crystal matrix protein.

The aim of this study was to determine the immunohistochemical distribution and quantification of crystal matrix protein (CMP). CMP, a 31 kDa glycoprotein, is the principal macromolecule found in calcium oxalate crystals generated in human urine, and is a potent inhibitor of crystal aggregation. A polyclonal rabbit anti-human CMP antibody was used to examine renal tissue by immunohistochemical techniques and light microscopy (N = 45). Twenty-five other human organs were similarly assessed. Quantification was performed using a visual analogue scale. CMP was visible as cytoplasmic staining in the epithelial cells of the TALH and the distal convoluted tubule including the macula densa in a subgroup of nephrons. CMP was not identified elsewhere in the urinary tract or in the extrarenal organs examined. Despite a trend indicating that the kidneys of normal men had more CMP than those of normal women, the difference failed to reach significance (P = 0.11). There was, however, more CMP in the stone formers group compared with either normal men (P < 0.01) or normal women (P < 0.01). This protein may be an important determinant of calcium oxalate kidney stone disease.

Aged↗

PubMed1990

Microwave warming of 1.5% glycine solution.

The urological irrigating fluid 1.5% glycine is routinely warmed in specifically designed warming drawers prior to use. This study shows that the use of microwave energy to achieve body temperature in 2-litre bags of glycine solution is biochemically safe and that the sterility of the solution is maintained. There is a linear relationship between the temperature of the solution and time in the microwave oven, so allowing a simple formula to predict the correct heating time given variable ambient starting temperatures.

Glycine↗