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Biomedical subjects

J Nelsen

Publications and source records attributed to J Nelsen.

3 recordsLinked to original sources

Anaerobic power performance and the menstrual cycle: eumenorrheic and oral contraceptive users.

AIM: The purpose of this project was to compare the impact of the menstrual cycle on short-term, high intensity (power) performance in active females who either had normal menstrual cycles (NOC) or who were using oral contraceptives (OC). METHODS: Subjects (7 NOC, 17 OC) completed a Margaria-Kalamen staircase test and a Wingate cycle test on 3 occasions: one for familiarization and the other two trials (random order) during menses (MEN) or luteal (LUT) phase. Phase was documented by urinary luteinizing hormone for the NOC. RESULTS: There were no significant differences between MEN and LUT in the NOC group on the Wingate test (n=7) for any of the following: peak power (P=0.33), peak power per kg body weight (P=0.37), anaerobic capacity (P=0.37), anaerobic capacity per kg body weight (P=0.42), power decline (P=0.36), power decline per kg body weight (P=0.35). Also there were no significant differences in power (P=0.95) for the Margaria-Kalamen test (n=6). There were no significant differences between MEN and LUT in the OC group for any of the following variables calculated from the subjects' performance on the Wingate test (n=17): peak power (P=0.39), peak power per kg body weight (P=0.36), anaerobic capacity (P=0.42), anaerobic capacity per kg body weight (P=0.36), power decline (P=0.57), power decline per kg body weight (P=0.66). Also there were no significant differences in power (P=0.44) for the Margaria-Kalamen test (n=11). CONCLUSIONS: For a moderately active group of women, anaerobic power performance was not influenced by menstrual cycle phase in either NOC or OC users.

Adult↗

Isolation and characterization of two safflower oleoyl-acyl carrier protein thioesterase cDNA clones.

Oleoyl-acyl carrier protein (18:1-ACP) thioesterase has been partially purified from developing safflower (Carthamus tinctorius) seeds. Protein species with molecular masses of 34 and 40 kD associated with thioesterase activity were identified and partially sequenced. Analysis of amino-terminal and internal cyanogen bromide peptide sequences revealed no differences in the primary structure of the two species. Amino acid sequence was used to design degenerate oligonucleotides for primers in a polymerase chain reaction (PCR) using safflower embryo cDNA as a template. A 380-base pair PCR product was used to isolate two classes of cDNA clones, designated 2-1 and 5-2, from the embryo cDNA library. Clone 2-1 encodes a 389-amino acid protein including a 60-amino acid transit peptide, and contains all of the protein sequence determined from the 34- and 40-kD proteins. Clone 5-2 encodes a 385-amino acid protein with 80% identity to that encoded by 2-1. Expression of the two safflower cDNA clones in Escherichia coli resulted in a 50- to 100-fold increase in the level of 18:1-ACP thioesterase activity. Both thioesterases are most active on 18:1-ACP; however, the enzyme encoded by 5-2 shows less discrimination against saturated 16- and 18-carbon acyl-ACP substrates.

Journal Article↗