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Biomedical subjects

M J Martin

Publications and source records attributed to M J Martin.

At least 145 records · Page 8Linked to original sources
PubMed1976

Conditions for collection of serum samples for the measurement of fibrin(ogen) degradation products by radioimmunoassay of fragment E.

A number of conditions have been assessed for the collection of serum samples for the measurement of fibrin(ogen) degradation products using a radioimmunoassay for degradation fragment E, which permits precise quantitation of differences. Blood should be collected using minimal venous occlusion into glass tubes containing 10 mg/ml of epsilon amino caproic acid and allowed to clot at 4 to 20 degrees C for at least 4 hours before centrifugation. The serum may be stored at 4 or -20 degrees C. Samples from patients receiving anticoagulant therapy should be treated with 10 IU of thrombin per ml.

Aminocaproates↗
PubMed1975

A comparison between radioimmunoassay and other immunological techniques for the measurement of fibrinogen/fibrin degradation products in serum.

Fibrinogen/fibrin degradation products (FDP) have been measured in serum by radioimmunoassay for fragment E (FgE), one of the terminal fragments in plasmic digestion of fibrinogen, and the results compared with those determined by both a tanned red cell haemagglutination inhibiton immunoassay (TRCHII) and a latex particle agglutination inhibition immunoassay. The detection limit of the FgE assay was 0.8 ng/ml, that of TRCHII was 625 ng/ml and the latex particle agglunitaion inhibition immunoassay was 10 mug/ml. All the samples measured had detectable levels of FDP with the FgE assay, whereas only 88% were measurable with the TRCHII and 2% by the latex particle agglutination inhibition immunoassay. A comparison of those samples giving a positive result with both the TRCHII and FgE assay showed overall agreement between the results of the two types of assay, but there was considerable scatter of FgE levels at each point of the TRCHII. The major advantages of the radioimmunoassay system are greater sensitivity, specificity and reproducibility.

Anemia, Sickle Cell↗
PubMed1975

The development of radioimmunoassays for fibrinogen degradation products: fragments D and E.

Fibrinogen degradation products, fragment D (FgD) and fragment E (FgE) have been measured in human serum by specific radioimmunoassays. In addition, the appearance of a neoantigenic determinant on FgD, revealed when fibrinogen is degraded by plasmin has been utilized to develop a specific radioimmunoassay for FgD in plasma (FgDneo). The reagents and conditions used in each assay are described in detail. The mean specific activity was 144 muCi/mug for 125I-labelled FgE and 82 muCi/mug for 125I-labelled FgD. Separation of antibody bound and free antigen was achieved using second antibody. The detection limits of the FgE, FgD and FgDneo assays were 0.8, 1.0 and 6.2 ng/ml respectively. The specificity of each assay with respect to fibrinogen and its degradation fragments has been assessed. Fibrinogen and fragment X cross-reacted markedly in both the FgE and FgD assays, whereas the cross-reaction of fibrinogen was abolished in the FgDneo assay, while the cross-reaction of fragment X was 10%, indicating gradual emergence of the neoantigenic site during digestion of fibriogen. The sensitivity, precision, and specificity of the radioimmunoassay systems described have major advantages over the existing procedures for the measurement of fibrinogen degradation products.

Antibody Specificity↗
PubMed1973

The transport of L-tryptophan from cerebrospinal fluid in the dog.

1. Endogenous tryptophan is uniformly distributed in dog cerebrospinal fluid (c.s.f.) and is about one tenth of the normal fasting plasma level.2. Using a recirculatory ventriculo-cisternal perfusion technique in conscious dogs it was found that L-tryptophan was removed from c.s.f. by a non-saturable mechanism in addition to bulk absorption of c.s.f. The clearance of L-tryptophan from c.s.f. was unaffected by thiopentone anaesthesia.3. Dialysis of dog plasma against an artificial c.s.f. solution containing L-tryptophan demonstrated that a large proportion of the tryptophan in dog plasma was protein-bound and that the unbound diffusible proportion would equilibrate with tryptophan concentrations equivalent to those normally found in dog c.s.f.4. Use of an open-circuit ventriculo-cisternal perfusion system in unanaesthetized dogs revealed the presence of a saturable component in the transport of tryptophan from c.s.f.5. As [(14)C]L-tryptophan infused into a recirculatory perfusion system produced no radioactively labelled metabolites, it was concluded that removal of tryptophan from c.s.f. by cerebral metabolism does not contribute substantially to maintaining the low levels of tryptophan in c.s.f. but that brain uptake associated with protein-binding may give rise to a small saturable component. The results indicate that the actual concentration gradient of tryptophan between plasma and c.s.f. is much less than it appears from the total concentration of tryptophan in the two fluids, and that the mechanism by which the c.s.f. - plasma distribution of tryptophan is maintained is mainly attributable to simple diffusion.

Anesthesia↗