Demonstration of 5-hydroxytryptamine in blood platelets by electron microscope autoradiography.
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Animals↗
Biomedical subjects
D Kay
Publications and source records attributed to D Kay.
Evidence for neuromuscular fatigue during high-intensity cycling in warm, humid conditions.
The purpose of this study was to examine and describe the neuromuscular changes associated with fatigue using a self-paced cycling protocol of 60-min duration, under warm, humid conditions. Eleven subjects [mean (SE) age 21.8 (0.8) years; height 174.9 (3.0) cm; body mass 74.8 (2.7) kg; maximum oxygen consumption 50.3 (1.8) ml.kg.min-1] performed one 60-min self-paced cycling time trial punctuated with six 1-min "all out" sprints at 10-min intervals, while 4 subjects repeated the trial for the purpose of determining reproducibility. Power output, integrated electromyographic signal (IEMG), and mean percentile frequency shifts (MPFS) were recorded at the mid-point of each sprint. There were no differences between trials for EMG variables, distance cycled, mean heart rate, and subjective rating of perceived exertion for the subjects who repeated the trial (n = 4). The results from the repeated trials suggest that neuromuscular responses to self-paced cycling are reproducible between trials. The mean heart rate for the 11 subjects was 163.6 (0.71) beats.min-1. Values for power output and IEMG expressed as a percentage of that recorded for the initial sprint decreased during sprints 2-5, with normalised values being 94%, 91%, 87% and 87%, respectively, and 71%, 71%, 73%, and 77%, respectively. However, during the final sprint normalised power output and IEMG increased to 94% and 90% of initial values, respectively. MPFS displayed an increase with time; however, this was not significant (P = 0.06). The main finding of this investigation is the ability of subjects to return power output to near initial values during the final of six maximal effort sprints that were included as part of a self-paced cycling protocol. This appears to be due to a combination of changes in neuromuscular recruitment, central or peripheral control systems, or the EMG signal itself. Further investigations in which changes in multiple physiological systems are assessed systematically are required so that the underlying mechanisms related to the development of fatigue during normal dynamic movements such as cycling can be more clearly delineated.
Adolescent↗
Initial experience with a prototype staple detector.
Stainless steel staples can be overgrown by granulation tissue or skin grafts and become buried in tissue. Although they are generally asymptomatic, they can on rare occasion erode to the surface or complicate the radiographic evaluation of pain not related to the staples. A device to facilitate detection of retained staples would be desirable, but it has been difficult to develop because stainless steel staples have poor magnetic and conductive properties. A prototype device, based on the presence of metal disturbing a low-power electromagnetic field, was developed. With human studies committee approval, this miniaturized detector was used in 13 burn patients to detect staples during planned removal of large numbers of staples. Staples were first removed using visual inspection and palpation of the wounds. This was followed by use of the staple detector. The age of the patients was 10.8 +/- 3.3 years, and burn size was 54.6 +/- 8.8% of the body surface. In 8 (62%) of the patients one or more additional staples were detected by the device that would otherwise have been overlooked. In 4 (31%) of the patients there was a false-positive signal, possibly related to topical silver in the wounds, that required additional focused physical examination. A portable staple detector has been developed. Initial experience with the device is favorable and warrants an expanded trial, which is in the planning stages.
Adolescent↗
Kinetic modeling of bioavailability for sorbed-phase 2,4-dichlorophenoxyacetic acid.
The degradation rate of 2,4-dichlorophenoxyacetic acid (2,4-D) was studied in silica-slurry systems to evaluate the bioavailability of sorbed-phase contaminant. After the silica particles were saturated with 2,4-D, the system was inoculated with the 2,4-D-degrading microorganism Flavorbacterium sp. strain FB4. The disappearance rate of 2,4-D was found to be greater than the rate predicted based upon liquid-phase 2,4-D concentrations. A kinetic formulation, termed the enhanced bioavailability model, was developed to describe the desorption and biodegradation processes in this batch system. The approach assumes that 2,4-D resides in both the liquid and solid phases and degradation occurs via both suspended and attached biomass. All biomass can degrade liquid-phase 2,4-D at one rate, while only attached biomass can degrade sorbed 2,4-D at another rate. An enhanced transformation factor (Ef) was introduced to express the increased biodegradation rate over that expected from the liquid phase only. This approach was able to account for the increased degradation rates observed experimentally. The results provide evidence that desorption to the bulk solution is not prerequisite to degradation, and that sorbed substrate may be available for degradation.
2,4-Dichlorophenoxyacetic Acid↗
Infantile chlamydial conjunctivitis. A comparison of Papanicolaou, Giemsa and immunoperoxidase staining methods.
The use of conjunctival smears to diagnose infantile Chlamydia trachomatis infection increased sixteen-fold in our hospital between the years 1979 and 1984. The present study was conducted to compare Papanicolaou and Giemsa staining methods with the avidin-biotin technique of immunostaining utilizing a highly specific antichlamydial monoclonal antibody. On retrospective review of 33 patients, chlamydial infection was diagnosed in 61% of the Papanicolaou-stained and 64% of the Giemsa-stained slides. After the Papanicolaou-stained slides were destained and immunostained with the antichlamydial antibody, round particles corresponding in size to elementary and reticulate bodies were readily seen in 79% of the cases. In comparison with the immunoperoxidase method, the sensitivity and specificity of Papanicolaou staining were 73% and 86%, respectively, while the corresponding figures for Giemsa staining were 77% and 100%, respectively. The study established the applicability of the immunoperoxidase method to this clinical condition, confirmed the accuracy of diagnoses with routine stains and highlighted the increasing incidence of chlamydial conjunctivitis in our hospital population.
Chlamydia Infections↗