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Full-Text Articles in Cell and Developmental Biology

A Thyroid Hormone-Regulated Gene In Xenopus Laevis Encodes A Type Iii Iodothyronine 5-Deiodinase., Donald L. St Germain, Robert Schwartzman, Walburga Croteau, Akira Kanamori, Zhou Wang, Donald D. Brown, Valerie Galton Aug 1994

A Thyroid Hormone-Regulated Gene In Xenopus Laevis Encodes A Type Iii Iodothyronine 5-Deiodinase., Donald L. St Germain, Robert Schwartzman, Walburga Croteau, Akira Kanamori, Zhou Wang, Donald D. Brown, Valerie Galton

Dartmouth Scholarship

The type III iodothyronine 5-deiodinase metabolizes thyroxine and 3,5,3'-triiodothyronine to inactive metabolites by catalyzing the removal of iodine from the inner ring. The enzyme is expressed in a tissue-specific pattern during particular stages of development in amphibia, birds, and mammals. Recently, a PCR-based subtractive hybridization technique has been used to isolate cDNAs prepared from Xenopus laevis tadpole tail mRNA that represent genes upregulated by thyroid hormone during metamorphosis. Sequence analysis of one of these cDNAs (XL-15) revealed regions of homology to the mRNA encoding the rat type I (outer ring) 5'-deiodinase, including a conserved UGA codon that encodes selenocysteine in …


Analysis Of Human Sperm Chromatin Integrity, Silvina M. Bocca Apr 1994

Analysis Of Human Sperm Chromatin Integrity, Silvina M. Bocca

Theses and Dissertations in Biomedical Sciences

Determining potential maternal or paternal sources of abnormal chromosomal constitution gives opportunity for preconception genetic counseling. The most direct determination is achieved by analyzing the nuclear constitution of the gametes.

The present study evaluated the integrity of human spermatozoal nuclear material in the two condensation stages of chromatin and chromosomes. Original semen samples (ORI) and their swim-up fractions (SW, selected for motility) from men of known (donors) and unknown (patients) fertility were analyzed. The extent of chromatin condensation was assessed by light microscopy and flow cytometry during the time course of a chemically-induced decondensation reaction.

Motile spermatozoa were used to …


Development And Application Of A Thermistor Current Meter, Carl M. Way, Albert J. Burky, Christine Miller-Way Jan 1994

Development And Application Of A Thermistor Current Meter, Carl M. Way, Albert J. Burky, Christine Miller-Way

Biology Faculty Publications

This report provides details for the construction of a hot-bead thermistor current meter which is capable of measuring water velocities on a millimeter spatial scale and for the construction of a compact and accurate calibration system. Hot-bead thermistor current meters can be built with response times of 200 ms capable of measuring velocities between 0.1 and 80 cm s-1. The construction of a sturdy probe for application in lotic systems such as high gradient Hawaiian streams was achieved by the use of heavy-duty acrylic tubing, small stainless steel gas-chromatography tubing, and flexible Tygon spaghetti tubing. An acrylic handle anchors the …