The endogenous cannabinoid agonist, anandamide stimulates sensory nerves in guinea-pig airways.

The endogenous cannabinoid agonist, anandamide produced a modest contractile response in guinea-pig isolated bronchus compared with the vanilloid receptor agonist capsaicin. The contractile response to both anandamide and capsaicin was inhibited by the vanilloid receptor antagonist, capsazepine. Furthermore, the NK(2)-selective antagonist, SR48968 but not the NK(1)-selective antagonist, SR140333 inhibited contractile responses to anandamide. The contractile response to anandamide was abolished in tissues desensitized by capsaicin. However, anandamide failed to cross-desensitize the contractile response to capsaicin. The contractile response to anandamide was not significantly altered in the presence of the CB(1) receptor antagonist, SR141716A, nor the amidase inhibitor, phenylmethylsulphonyl fluoride (PMSF) but was significantly increased in the presence of the neutral endopeptidase inhibitor, thiorphan. The cannabinoid agonist, CP55,940 failed to significantly attenuate the excitatory non-adrenergic non-cholinergic (eNANC) response in guinea-pig airways. In contrast, the ORL(1) receptor agonist, nociceptin, significantly inhibited this response. The results demonstrate that anandamide induces a modest contractile response in guinea-pig isolated bronchus that is dependent upon the activation of vanilloid receptors on airway sensory nerves. However, cannabinoid receptors do not appear to play a role in this regard, nor in regulating the release of neuropeptides from airway sensory nerves under physiological conditions.

Ethics in the mentoring of gerontologists: rights and responsibilities.

This article examines professional codes of ethics as they apply to the mentoring of gerontology students, supervisees, or proteges. Ethics codes from the disciplines represented in professional gerontology were evaluated according to the specificity of their ethical mentoring guidelines. Three levels of specificity were identified. General "do no harm" statements are most common. Clear, explicit guidelines or rules are much less frequent. Where explicit mentoring guidelines exist, they focus on the use or misuse of the power of the professional/mentor in the mentoring relationship. Specific suggestions regarding the rights and responsibilities of both parties in the mentoring relationship, reflecting both formal ethics codes and the authors, experiences, are made.

Resting metabolic rate, body composition and aerobic fitness comparisons between active and sedentary 54-71 year old males.

OBJECTIVE: To test the hypothesis that 55-70 y old male longterm exercisers (LE) have higher resting metabolic rates (RMR) than longterm nonexercisers (LNE). DESIGN: A power analysis demonstrated that this cross-sectional study required 12 subjects per group to detect a 10% RMR difference (kJ x kg FFM(-1) x d(-1)) between the LE and LNE (power = 0.8;alpha = 0.05). SUBJECTS: Twelve LE (X +/- s.d.; 63.5+/-3.4 y; 1.75+/-0.06 m; 69.01+/-8.24 kg; 20.4+/-4.9 %BF) and 12 LNE (63.6+/-5.6 y; 1.72+/-0.07 m; 79.44 12.4 kg; 29.6 4.4 %BF) were recruited from advertisements placed in a newspaper and on university and community noticeboards. INTERVENTIONS: Measurements were conducted for: RMR using the Douglas bag technique; body composition via a four compartment model which is based on determination of body density, total body water and bone mineral mass; and aerobic fitness using a submaximal work test on a cycle ergometer. RESULTS: The LE (93.00+/-7.16 kJ x kg(-1) x d(-1)) registered a significantly greater (P = 0.04) RMR than the LNE (84.70+/-11.23 kJ x kg(-1) x d(-1)) when energy expenditure was expressed relative to body mass, but this difference disappeared (P = 0.55) when the data were corrected for the non-zero intercept of the graph of RMR (MJ/d) against body mass. ANCOVA with FFM as the covariate also indicated that the RMR (MJ/d) difference between the groups was not statistically significant (P = 0.28). The adjusted means for the LE and LNE were 6.39 and 6.62 MJ/d, respectively. CONCLUSIONS: There are no RMR (MJ/d) differences between LE and LNE 54-71 y old males when statistical control is exerted for the effect of FFM and the higher value of the former group for RMR normalised to body mass disappears when this ratio is corrected for statistical bias.

Energy metabolism in sedentary and active 49- to 70-yr-old women.

This study examined differences between long-term exercising (LE) and long-term nonexercising (LNE) women [n = 24; age 56.4 +/- 6.2 (SD) yr] for resting metabolic rate (RMR) and energy expenditure in the free-living state by using doubly labeled water (DLW). There was a statistically significant difference (P = 0.0002) between the 12 LE (94.85 +/- 8.44 kJ . kg-1 . day-1) and 12 LNE (81.16 +/- 6.62 kJ . kg-1 . day-1) for RMR, but this difference was only marginally significant (P = 0.06) when the data (MJ/day) were subjected to an analysis of covariance with fat-free mass as the covariate. The DLW data indicated that the eight most active LE (12.99 +/- 3.58 MJ/day) expended significantly (P = 0.01) more energy than did the eight least active LNE (9.30 +/- 1.15 MJ/day). Energy expenditures ranged from 7.64 to 18.15 MJ/day, but there was no difference (P = 0.96) between the LE and LNE in energy expenditure during activity that was not designed to either improve or maintain fitness. These cross-sectional data on 49- to 70-yr-old women therefore suggest that 1) aerobic-type training results in a greater RMR per unit of body mass and also when statistical control is exerted for the effect of the metabolically active fat-free mass, 2) there is a large range in the energy intake necessary to maintain energy balance, and 3) aerobic training does not result in a compensatory reduction in energy expenditure during the remainder of the day.

Electrical conductivity of pH-responsive hydrogels.

The electrical conductivity of pH-responsive hydrogels based on cross-linked poly(2-hydroxyethyl methacrylate-co-dimethylaminoethyl methacrylate) copolymers has been studied as a function of pH over the range 5-10, for copolymers containing up to 20 mol% of the amine-containing comonomer. The conductivities of membranes equilibrated in buffered potassium chloride solutions were determined by measuring the electrical resistance of a membrane mounted between the chambers of a modified side-by-side diffusion cell. The conductivity, expressed as a fraction of the conductivity of the buffer in which the gels were equilibrated, ranged from 1% for the gels in the collapsed state to 70% for the most highly swollen gels. The observed results are qualitatively consistent with a proposed model in which the ion concentrations in the fluid phase of the gel are described by Donnan partitioning, and the ion mobilities by the free-volume theory of Yasuda. The results suggest that conductivity measurements may provide an alternative to diffusive transport studies for characterizing moderately swollen hydrogel membranes.

Surface analysis of clinically used expanded PTFE endoscopic tubing treated by the STERIS PROCESS.

The repeated use of semicritical and critical medical instruments in clinical procedures carries an inherent risk of subsequent patient infection, necessitating "high-level" disinfection or sterilization. However, residual bio-organic contamination may hinder the ability of such processes to efficiently destroy infectious microbes. In this study, the inner surfaces of three clinically used expanded polytetrafluoroethylene endoscope tubes treated with glutaraldehyde disinfectant solutions were analyzed to quantify the efficacy of a buffered peracetic acid sterilization procedure, the STERIS PROCESS, in removing this contamination. Samples of the flexible distal biopsy channel of colonoscope tubes were examined before and after a variable number of STERIS processing cycles by three complementary surface characterization techniques: Fourier transform infrared spectroscopy (FTIR), electron spectroscopy for chemical analysis (ESCA), and atomic force microscopy (AFM). Glutaraldehyde fixed protein deposits identified on the tubing surface decreased with increased STERIS cycles. After 20 STERIS cycles, FTIR data indicated that approximately 30% of the contamination was removed, whereas ESCA indicated that 50% of the contamination was removed. AFM images showed considerable variation between control and processed samples, including evidence for cracks in the residual contamination layer. Clinical glutaraldehyde treatment and subsequent device drying are suggested to be two majors factors that limit effective cleaning of endoscopic tubing.

Non-denaturing assay for the determination of the potency of recombinant bovine somatotropin by high-performance size-exclusion chromatography.

A non-denaturing high-performance size-exclusion chromatographic method has been developed for the determination of the potency of recombinant bovine somatotropin (rbST) in bulk materials. A Spherogel TSK 3000 PW column containing a polymer base packing material with very hydrophilic bonded surface was used in this method. Ammonium hydrogencarbonate buffer pH 9.0, was used as the mobile phase. This method was shown to be non-denaturing by rat mass-gain assay and radioreceptor assay. The optimization for the separation and determination of rbST has been investigated. The method was validated for the determination of rbST in bulk materials. In addition, rbST soluble aggregates formed in the production process due to protein association, used to be found in bulk materials. The behavior of rbST soluble aggregates in ammonium hydrogencarbonate solutions have been studied. The bio-inactive aggregates can be separated by the method developed in this study. The high-low chromatographic technique has been used to estimate rbST soluble aggregates in bulk materials.

Precision and accuracy of Morgan ventilometers at continuous and sinusoidal flows.

The P.K. Morgan Mark II Ventilometer comprises a turbine transducer and a control/readout unit, which contains either a VENTX5A or VENTX6A programme. This equipment is used to measure minute ventilation during oxygen consumption tests. The precision and accuracy of six of these devices (a VENTX5A with two turbines, and two VENTX6As each with two different turbines) were examined during continuous and pulsatile flows; accuracy was affected by the syringe rate during the calibration procedure. The reference standard was a 350 l Collins chain-compensated gasometer. At continuous flows, the two VENTX5A devices showed accuracies of 99.5-100.5% over the range 60-160 l.min-1 whereas those for the four VENTX6As were 99.3-102.1% over the range 60-200 l.min-1. The mean accuracies of sinusoidal flows for the VENTX5A ranged between 96.1-101.3% for minute volumes spanning 15-200 l.min-1; comparable data for the VENTX6As were 95.9-98.9%. These mean accuracies improved to 98.1-101.3% for the VENTX5A at measured minute volumes > 80 l.min-1. Omission of the two lowest tidal volumes (1 and 1.5 l) for the VENTX6As narrowed the range of accuracy to 96.9-98.5%. The coefficients of variation for five trials at each minute ventilation were 0-0.2%. We conclude that, while the P.K. Morgan Mark II Ventilometer has excellent precision, its accuracy is dependent on the calibration syringe rate, minute ventilation and program.

Structure of an insect virus at 3.0 A resolution.

We report the first atomic resolution structure of an insect virus determined by single crystal X-ray diffraction. Black beetle virus has a bipartite RNA genome encapsulated in a single particle. The capsid contains 180 protomers arranged on a T = 3 surface lattice. The quaternary organization of the protomers is similar to that observed in the T = 3 plant virus structures. The protomers consist of a basic, crystallographically disordered amino terminus (64 residues), a beta-barrel as seen in other animal and plant virus subunits, an outer protrusion composed predominantly of beta-sheet and formed by three large insertions between strands of the barrel, and a carboxy terminal domain composed of two distorted helices lying inside the shell. The outer surfaces of quasi-threefold related protomers form trigonal pyramidyl protrusions. A cleavage site, located 44 residues from the carboxy terminus, lies within the central cavity of the protein shell. The structural motif observed in BBV (a shell composed of 180 eight-stranded antiparallel beta-barrels) is common to all nonsatellite spherical viruses whose structures have so far been solved. This highly conserved shell architecture suggests a common origin for the coat protein of spherical viruses, while the primitive genome structure of BBV suggests that this insect virus represents an early stage in the evolution of spherical viruses from cellular genes.

Black beetle virus--crystallization and particle symmetry.

Black beetle virus, propagated in cultured Drosophila cells, crystallized into rhombic dodecahedra which diffracted X rays to 3.0 A resolution. Center-to-center spacing of particles in the unit cell was 305 A, while the spherically averaged diameter obtained from small-angle X-ray scattering from virus in solution was 312 A. Low resolution diffraction patterns from single crystals showed that the protein subunits are distributed centrosymmetrically, while electron microscopy indicated the particles are icosahedral in shape. The size of the particle is sufficient to accommodate about 180 protein subunits (44 kDa) consistent with T = 3 quasisymmetry.

The role of paraprofessional: an administrative dilemma.

Changing a paraprofessional's title will do little to improve his or her position. If they are to compete successfully in the status and power sweepstakes, paraprofessionals must continue their education. Administrators should make career development opportunities available if they hire paraprofessionals.