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Biomedical subjects

H K Smith

Publications and source records attributed to H K Smith.

27 records · Page 2Linked to original sources
PubMed1992

Inducible cell ablation in Drosophila by cold-sensitive ricin A chain.

We have developed a system for temperature-inducible killing of specific cells in the fruitfly Drosophila melanogaster. The system overcomes many of the limitations of existing cell ablation methods and is in principle applicable to any non-homeothermic eukaryote. Temperature-sensitive and cold-sensitive mutations in the ricin toxin A chain (RTA) of castor bean were generated in yeast. One cold-sensitive mutation, RAcs2, produced temperature-dependent ablation of eye cells in Drosophila when expressed under control of the eye-specific sev enhancer. At 29 degrees C, cell death was observed within 7 hours in the developing eye and no obvious toxic effects were observed elsewhere; at 18 degrees C, extremely low toxicity was observed. DNA sequencing of RAcs2 revealed a single amino acid substitution in the RTA active site cleft.

Animals↗
PubMed1991

Physiological characteristics of elite female basketball players.

Successful performance in international basketball competition requires an appreciation of the physical demands of the sport and the capacities of the team to respond to those demands. Optimal performance now requires a combination of technical and tactical abilities as well as a high degree of physical fitness. The objectives of this study were to assess physiological components considered important to game performance in players selected to the national team roster in 1988 or 1989, and to use this information to describe the team and positional profiles. Data obtained from maximal treadmill tests, anthropometry, sprints, isokinetic dynamometry, and other tasks reflected those qualities required of elite players. In relation to previously reported data, the athletes were generally taller and heavier and had higher maximal aerobic power than international and college players of 7 to 10 years ago. The data can also be used to identify target standards for current and prospective team members.

Adult↗
PubMed1989

Physiological profiles of the Canadian National Judo Team.

The physiology of Canadian National Judo Team members is described. These athletes differed widely in body size (height 157.4-187.7 cm; mass 56.5-100.8 kg). Aerobic fitness (treadmill) was high (VO2max = 4.49 I.min-1; 59.2 mL.kg-I.min-I), but relative VO2max decreased with increasing body mass. Elite judoka of other nations (Australia, 53.2; Poland, 59.0; Norway, 58.5) had comparable aerobic fitness. Significant (p less than 0.05) correlations between upper- (arm cranking, PWC170) versus lower-body aerobic fitness (r = 0.48), and upper- versus lower-body anaerobic power (r = 0.89) and capacity (r = 0.88) (Wingate) were observed. Peak power output (AnPP = 9.3 W.kg-I) and anaerobic capacity (AnCap = 260 J.kg-I) during arm cranking averaged 80% of leg-cranking values (AnPP = 13.7 W.kg-I; AnCap = 320 J.kg-I). Upper-body strength (bench press, one repetition, maximum = 100 kg) was also associated with upper-body anaerobic power (r = 0.72). Judoka exhibit a high degree of aerobic and anaerobic conditioning, and a pattern of total body fitness that is specifically required for their sport.

Adolescent↗
PubMed1988

The aerobic demand of backstroke swimming, and its relation to body size, stroke technique, and performance.

Few studies have examined the aerobic demand of backstroke swimming, and its relation to body morphology, technique, or performance. The aims of this study were thus to: i) describe the aerobic demand of backstroke swimming in proficient swimmers at high velocities; ii) assess the effects of body size and stroke technique on submaximal and maximal O2 costs, and; iii) test for a relationship between submaximal O2 costs and maximal performance. Sixteen male competitive swimmers were tested during backstroke swimming at velocities from 1.0 to 1.4 m.s-1. Results showed that VO2 increased linearly with velocity (m.s-1) following the equation VO2 = 6.28v - 3.81 (r = 0.77, SEE/Y = 14.9%). VO2 was also related to the subjects' body mass, height, and armspan. Longer distances per stroke were associated with lower O2 costs, and better maximal performances. A significant relation was found between VO2 at 1.1 m.s-1, adjusted for body mass, and 400 m performance (r = -0.78). Submaximal VO2 was also related to reported times for 100 m and 200 m races. Multiple correlation analyses indicated that VO2 at 1.1 m.s-1 and VO2max accounted for up to 78% of the variance in maximal performances. These results suggest that the assessment of submaximal and maximal VO2 during backstroke swimming may be of value in the training and testing programs of competitive swimmers.

Adolescent↗
PubMedDate not supplied

Comparison of resin and solution screening methodologies in combinatorial chemistry and the identification of a 100 nM inhibitor of trypanothione reductase.

Two identical polyamine peptide conjugate libraries were screened against the parasitic enzyme trypanothione reductase. One of these libraries was in a solution format, while the other was resin-based and was used in two resin-based screens (a diminution assay and a direct bead screening). Potent inhibitors (100 nM) of trypanothione reductase were identified both in the solution screen and in the resin-based screens when using the PEGA resin of Meldal. Resin screening of both types failed to work with TentaGel resin. Importantly there was excellent agreement between the solution and resin-based assays, suggesting both methods are reliable for the screening of combinatorial libraries.

Combinatorial Chemistry Techniques↗