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Biomedical subjects

W F Reynolds

Publications and source records attributed to W F Reynolds.

9 recordsLinked to original sources
PubMed1992

Cell culture of Taxus as a source of the antineoplastic drug taxol and related taxanes.

Callus cultures of Taxus cuspidata and Taxus canadensis were induced using different tissue explants including green and red arils, seed contents, young stems and needles. Callus derived from stem segments displayed the best growth in defined media. The culture medium was supplemented with reducing agents and phenolic-binding compounds to inhibit callus darkening and subsequent growth reduction. T. cuspidata explant growth was affected by different concentrations and ratios of 2,4-D and kinetin. Callus tissues of T. cuspidata were extracted for taxol after 2 months in culture and analysed by HPLC. The presence of taxol (0.020 +/- 0.005% of the extracted dry weight) was indicated based on retention time, U.V. spectra, peak purity as assessed by photo-diode array spectroscopy and compared with an authentic taxol standard, as well as by 1H-NMR analysis. Suspension cultures of T. cuspidata were established from the callus cultures, subsequently immobilized onto glass fiber mats, and maintained as immobilized cultures for 6 months. The immobilized cell cultures also produced taxol at levels up to 0.012 +/- 0.007% of the extracted dry weight.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1992

Differential expression of oocyte-type class III genes with fraction TFIIIC from immature or mature oocytes.

The Xenopus OAX genes can be expressed in oocytes but are virtually inactive in somatic tissues. The tRNA(Met1) (tMET) genes also appear to be developmentally regulated. We have examined the reason for the differential expression of these class III genes. Analysis of the transcriptional activities of extracts derived from immature and mature oocytes revealed that the developmental regulation of these genes can be reproduced in vitro. We have partially purified the required transcription factors B and C from these extracts to ascertain the components responsible for this differential activity. The immature oocyte C fraction activates the tMET and OAX genes when reconstituted with either the immature or mature oocyte-derived B fraction. In contrast, the mature oocyte C fraction fails to activate these genes regardless of which B fraction is used. Both C fractions activated the somatic 5S gene. Purification of the oocyte C fractions by phosphocellulose or B box DNA affinity chromatography failed to separate additional activities responsible for the differential expression of OAX or tMET. By using template exclusion assays, the inability of the mature oocyte C fraction to activate transcription was correlated with an inability to form stable transcription complexes with the tMET or OAX gene.

Animals↗
PubMed1978

Uncommon radiologic observations in renal milk-of-calcium stone.

Milk-of-calcium stone is a rare finding in the kidney. It is diagnosed radiologically based on the fact that the opacity takes a semilunar shape and layers according to the position of the patient. An unusual observations is that layering may require some time to take place and that the semilunar configuration may be found incidentally in the supine position as well.

Adult↗
PubMed1977

Diagnostic problems of epithelial tumors of penis.

Malignant epithelial tumors of the penis often present aspects which make difficult an accurate clinical and pathologic diagnosis. Frequently, repeated biopsies yield a benign diagnosis while the tumor continues to progress and sections through it indicate malignant components. It is suggested that epithelial tumors of the penis may consist, in many instances from their start, of a mixture of benign and malignant elements in ratios varying from one extreme to the other. This may explain why biopsies are frequently misleading, yielding a benign result while, in fact, the tumor is malignant.

Aged↗
PubMed1977

Seeding mechanism of urothelium over nonepithelialized surfaces.

To study urothelial spreading over nonepithelialized tissue surfaces, bladder defects in rabbits were patched with pedicled prevesical fat. Using serial sections and scanning electron microscopic studies, it was concluded that urothelium in the process of covering nonepithelialized surfaces is able to seed at a distance from the periphery of the defect as one means of epithelializing a defect.

Adipose Tissue↗
PubMed1977

Determination of the preferred tautomeric form histamine by 13C nmr spectroscopy.

The pH-dependent 13C chemical shifts for histamine indicate an approximate 4: 1 preference for the N-H tautomer of the imidazole ring, similar to that previously deduced for L-histidine. It is concluded that the 13C chemical shift method is a complimentary technique to the method of determining tautomer preference from pK values. Factors determining the tautomer preference in histamine and L-histidine are discussed.

Histamine↗