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K M Williams

Publications and source records attributed to K M Williams.

152 records · Page 9Linked to original sources
PubMedDate not supplied

Two-dimensional electrophoresis of human serum proteins following acute myocardial infarction.

Serum proteins associated with acute myocardial infarction (AMI) have been monitored by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and high resolution two-dimensional electrophoresis (2-DE) under nonreducing conditions. Proteins a, b, c (Mr 13,000; pI6.2, 6.7 and 7.5, respectively) and e(Mr27,000; pI5.2) appear simultaneously approximately 30 h after infarction, reach maximum intensity after 48 h and progressively decline thereafter. Protein d (Mr15,000; pI7-8.5; identified as hemoglobin) sometimes appears within 18 h of infarction. Proteins a-c are not detected in the 2-DE patterns of healthy myocardium, infarcted myocardium, pectoral muscle or tongue, but e is present in all and tentatively identified as myosin light chain. Other myocardial proteins which are either reduced in amount following infarction or more specifically associated with myocardium than pectoral muscle are not detected in the serum of AMI patients. Analysis of unconcentrated urine by SDS-PAGE and silver staining does not reveal proteins specific to AMI.

Adult↗
PubMedDate not supplied

Assessment of in vitro and in vivo recovery of gallamine using microdialysis.

The application of microdialysis technique for the investigation of pharmacokinetics and pharmacodynamics of drugs requires careful assessment of probe performance to ensure validity of the data obtained using this technique. The aim of this study was to establish and validate the microdialysis technique for investigation of the pharmacokinetics and pharmacodynamics of the neuromuscular blocker, gallamine. In vitro recovery of gallamine from the microdialysis probe when different perfusion flow rates were employed was evaluated leading to selection of a flow rate of 2 microl/min with 15-min sampling intervals for the subsequent studies. In vitro recovery of gallamine from the microdialysis probe was independent of concentration, stable over an 8-h period and reproducible. Comparable in vitro recoveries were obtained by different established approaches including recovery estimation by gain, loss and the zero-net flux (ZNF) method. Recovery by loss was used to study the in vivo recovery of gallamine from rat muscle tissue. The in vivo recovery was stable over a 5.5-h sampling period. In vitro performance of the probe subsequent to the in vivo study remained stable supporting reusage of the probe. These data highlight the importance of a systematic examination of microdialysis probe validation.

Animals↗
PubMedDate not supplied

Stability of serum alanine aminotransferase activity.

In this study the authors examine the effects of common storage and handling procedures on serum alanine aminotransferase (ALT) levels. Clotted blood samples from 14 subjects were centrifuged at 280 X g for 10 minutes. Serum was tested immediately for baseline ALT levels and aliquots were stored at 22, 4, -20, and -80 degrees C. Additional serums were stored on the clot at 22 and 4 degrees C. ALT quantitation was performed at intervals of 3, 6, 9, and 24 hours and on Days 2, 4, 6, and 8. Unseparated tubes were sampled both proximal and distal to the red cells to determine ALT leakage from red cells lysis. For all storage conditions, gradual loss of activity occurred over time. Mean activity loss in separated serum at 2 days was 6 percent at 4 degrees C and 20 percent at 22 degrees C. Mean loss in unseparated serum was 3 percent at 4 degrees C and 12 percent at 22 degrees C. Marked ALT loss averaging 46 percent by day 6 occurred with storage at -20 degrees C, whereas storage at -80 degrees C resulted in an 8 percent decrease for the same period. For storage of up to 1 week, it is recommended that serum be separated early and retained at 4 degrees C. Frozen samples should be kept at -80 degrees C. Storage of separated or unseparated blood for up to 24 hours at 22 or 4 degrees C, as commonly found in blood centers, will marginally adversely affect the accuracy of ALT determination.

Alanine Transaminase↗
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Food Allergens.

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Allergens↗
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Requirements for HLA-B*2705-binding peptides with special regard to the transporter associated with antigen processing (TAP).

OBJECTIVE: To refine the algorithms governing peptide presentation by HLA-B*2705 by analyzing: (i) the specificity of the human transporter associated with antigen processing (TAP) for HLA-B27 binding peptides; and (ii) the peptide binding affinity to HLA-B*2705. METHODS: TAP-translocation was measured with a labeled reporter peptide containing an N-linked glycosylation acceptor site in Streptolysin O-permeabilized cells for a panel of HLA-B27 binding peptides. Peptide binding affinity was determined by peptide-induced stabilization of empty HLA-B*2705 expressed by the TAP-deficient cell line T2-B27. RESULTS: Human TAP preferentially translocated analogues with residues leucine, isoleucine, methionine and arginine as the carboxy-terminal amino acids, whereas analogues with aspartic acid and serine were translocated poorly. The binding affinity to HLA-B*2705 of the poorly translocated aspartic acid and serine analogues was about 100-fold less compared to the parent HLA-B27 binding peptide. CONCLUSIONS: Human TAP shows considerable specificity for the C-terminus of potential HLA-B27 ligands. Nonamer peptides with aspartic acid and serine at the C-terminus are poorly translocated by the TAP and have low binding affinity for HLA-B*2705, and are therefore unlikely to become presented by HLA-B*2705.

ATP-Binding Cassette Transporters↗