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Biomedical subjects

J K Smith

Publications and source records attributed to J K Smith.

At least 163 records · Page 9Linked to original sources
PubMed1975

Preparation of a glycoprotein fraction from pooled human plasma and its evaluation as a substrate for the assay of Clostridium welchii (C. perfringens) neuraminidase.

A glycoprotein fraction (fraction VII) suitable for use as a substrate in assays of microbial neuraminidase was prepared from pooled human plasma. It is pasteurised during preparation to eliminate the risk of transmission of serum hepatitis. This results in polymerisation of some of the gamma1-acid glycoprotein, but fraction VII is shown to be an excellent substrate for the neuraminidase of Clostridium welchii (C. perfringens). A sensitive assay procedure is described. A number of factors may interfere with the measurement of NANA released by the action of microbial neuraminidase and procedures are described for evaluation of this problem. Fraction VII is easy to prepare, cheap and available in standard form in large amounts (inquiries should be addressed to J. K. S.); it is recommended for routine use as a convenient substrate for neuraminidase assays.

Clostridium perfringens↗
PubMed1975

In vitro spontaneous thrombin generation in human factor-IX concentrates.

A series of in vitro studies designed to ascertain the potential in vivo thrombogenicity of human factor IX-containing concentrates is described. Using concentrates obtained from several different Centres the fibrinogen clotting time with some preparations was less than 6 h and/or the recalcification time of normal plasma was shortened. In some preparations, however, the plasma recalcification time was lengthened. Further studies revealed that all diluted factor-IX concentrates generated thrombin after recalcification, and that the rate of thrombin generation appeared to be characteristic of a particular preparation. This characteristic has been designated the TGt50, which is the incubation period in minutes, after recalcification, required to obtain a 50 s clotting time of a fibrinogen substrate. The TGt50 was found to correlate most strongly with recalcification time of celite exhausted plasma (P less than 0.001), but no correlation was observed between it and the immunological antithrombin III or factor-VIII antigen levels. Evidence is presented which suggests that the thrombin generation test and recalcification time of celite exhausted plasma may represent suitable in vitro quality control assays for factor-IX concentrates.

Blood Coagulation↗
PubMed1975

Alternatives to freeze-drying for the removal of ethanol from plasma proteins. II. Gel filtration of albumin.

Removal of ethanol from highly concentrated solutions of human albumin (Cohn fraction V) by gel filtration on Sephadex G-25 is hindered by the contraction of the gel in ethanolic solution, by incomplete retardation of ethanol compared with other low MW solutes, and by restricted diffusion of ethanol from the albumin zone. Despite these obstacles, the hourly capacity of such gel filtration columns, for approximately 100-fold reduction of ethanol concentration, may exceed 0.06 kg albumin per litre of column volume. The gel can be used safely at 5 degrees C for several years. The ethanol content of the final product is higher than that achieved by vacuum distillation, and it may be desirable to operate the two techniques sequentially.

Acrylamides↗
PubMed1974

A common tumour specific antigen. II. Further characterization of the whole antigen and of a cross-reacting antigen of normal tissues.

Experimental evidence supporting the postulated analogy between myelin basic protein and a previously described common tumour specific antigen is summarized under antigenic cross-reactivity, subcellular localization, molecular size, basicity and proteolipid nature. A third protein antigen, present in all tissues, also shows strong similarities in all these respects.

Antigen-Antibody Reactions↗