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Biomedical subjects

W C Thompson

Publications and source records attributed to W C Thompson.

50 records · Page 3Linked to original sources
PubMed1981

Taxol induces microtubule assembly at low temperature.

Dissociated bovine brain microtubule protein has been shown to reassemble at 0 degrees C in the presence of the drug taxol. Tubulin polymerization was monitored both by electron microscopy of the polymeric structures and by incorporation of tritiated GTP into filterable polymeric structures. Most of the labeled guanine nucleotide uptake into tubulin polymeric structures occurred in the first 30 minutes of incubation with the drug. The initial polymerization event results in the formation of protofilamentous tubulin ribbons. The first microtubules were noted after 1 hour of incubation with the drug. After 20 hours of incubation at 0 degrees C with taxol, the bulk of the polymerized tubulin appeared to be in the form of microtubules. Cold-stable tubulin rings with a mean diameter of 34 nm were present in the reaction mixture before the addition of taxol and throughout the 20-hour incubation. Most of the rings were apparently not involved in the taxol-induced microtubule assembly. The results are consistent with a model whereby taxol induces an initial formation of protofilamentous ribbon structures, mostly from free tubulin dimers, and a slower subsequent folding of the ribbon structures into microtubules.

Alkaloids↗
PubMed1979

Intact microtubules are required for rapid turnover of carboxyl-terminal tyrosine of alpha-tubulin in cell cultures.

In cultured muscle cells the carboxyl-terminal tyrosine of alpha-tubulin was shown to exchange rapidly with free tyrosine. The rapid turnover of this residue was dependent upon the presence of intact microtubules. Half-life determinations were made by two methods: (i) the cells were pulse-labeled in hypertonic medium, in which the major tyrosine incorporation was post-translational, and then chased with isotonic medium; and (ii) the cells were pulsed and chased in isotonic medium, and the post-translational component of the radioactivity of purified alpha-tubulin was calculated. Both methods yielded a half-life of 37 min or less for the terminal tyrosine residue, whereas the half-life of tubulin itself was shown to be greater than 48 hr.

Animals↗
PubMedDate not supplied

Actinomycetoma masquerading as an abdominal neoplasm.

Despite the fact that infection accompanying actinomycotic organisms is relatively rare, the possibility of such infection should be kept in mind because the organism is known to be commensal in the oral cavity, lungs, and intestinal tract. Abdominal lesions may mimic a neoplasm in many ways--physical findings, clinical course, and roentgenographic changes. Since the bacterium is anaerobic and difficult to grow on culture, one may have to rely on histologic confirmation for diagnosis. The infection can usually be eradicated by large doses of antibiotic (penicillin) over an extended period of time.

Abdominal Neoplasms↗
PubMedDate not supplied

Context effects in forensic science: a review and application of the science of science to crime laboratory practice in the United States.

This article discusses the phenomenon of "context effects" by reviewing the findings and practices of a range of scientific fields, including astronomy, physics, biology, medicine, and especially the relevant research and theory from psychology. Context information, such as expectations about what one is supposed to see or conclude, has been found to have a small but relentless impact on human perception, judgment, and decision-making. The article then considers the vulnerability of forensic science practice to context effects, and concludes by suggesting that forensic science adopt practices familiar in other fields of scientific work, in particular blind or double-blind testing and also the use of evidence line-ups.

Forensic Medicine↗