Biomedical subjects
Publications and source records attributed to J Ridley.
We examined the practice of transfusion for anaemia in our hospitals using an audit method, with standards derived from guidelines published by the British Committee for Standards in Haematology. Documentation was generally good, but simple tests were not performed prior to transfusion in many cases when the diagnosis was not known.
Where relatives compete for the same resources (kin competition) and each obtains an equal share, this can favour the evolution of elevated dispersal rates, such that most resource competition is among non-relatives. We show that this effect evaporates as among-sibling dominance increases to the point where the allocation of resources is maximally unequal. We restore a kin-competition effect on emigration rates from dominance-ranked family groups by showing that where siblings form queues to inherit the breeding positions, the length of the queue affects the fitness of all individuals by depreciating the rank of subsequent offspring. Incorporating this 'offspring depreciation' effect decreases optimal queue lengths, increases dispersal rates and explains the otherwise paradoxical use of sinks by cooperatively breeding birds in stable environments. The offspring depreciation effect also favours the evolution of small, but consistent, clutch sizes and high reproductive skew, but constrains the evolution of alloparenting.
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Resting cells of Desulfovibrio desulfuricans coupled the oxidation of a range of electron donors to Tc(VII) reduction. The reduced technetium was precipitated as an insoluble low-valence oxide. The optimum electron donor for the biotransformation was hydrogen, although rapid rates of reduction were also supported when formate or pyruvate was supplied to the cells. Technetium reduction was less efficient when the growth substrates lactate and ethanol were supplied as electron donors, while glycerol, succinate, acetate, and methanol supported negligible reduction. Enzyme activity was stable for several weeks and was insensitive to oxygen. Transmission electron microscopy showed that the radionuclide was precipitated at the periphery of the cell. Cells poisoned with Cu(II), which is selective for periplasmic but not cytoplasmic hydrogenases, were unable to reduce Tc(VII), a result consistent with the involvement of a periplasmic hydrogenase in Tc(VII) reduction. Resting cells, immobilized in a flowthrough membrane bioreactor and supplied with Tc(VII)-supplemented solution, accumulated substantial quantities of the radionuclide when formate was supplied as the electron donor, indicating the potential of this organism as a biocatalyst to treat Tc-contaminated wastewaters.
Dialysis saves lives. However, dialysis alone cannot make those lives active and meaningful. Exercise, in particular, is critical in the rehabilitation of many individuals with chronic renal insufficiency The purpose of this pilot study was to: 1) examine changes in participants' physical capacity and quality of life with the intervention of a 12-week exercise program; 2) investigate whether erythropoietin (EPO) and antihypertensive medication dosages were reduced in the participants; 3) examine the feasibility of incorporating exercise into the London Health Sciences Centre (LHSC) hemodialysis program. A quasi-experimental one-group pre- and post-test design was utilized. Eight subjects completed the 12-week study. The exercise program involved a warm-up, stretching, strengthening, and cardiovascular training. The results demonstrated improvements in the participants'physical capacity, quality of life, and ability to perform activities of daily living (ADLs). There were no discernable trends in the participants' hemoglobin levels or EPO dosages. Although there were no statistically significant changes in participants' blood pressures, five out of the six participants who began the program on antihypertensive medications either had the dosages decreased or the drug(s) discontinued. Data from this small prospective study supports previous research that an exercise during dialysis program is safe and has the potential to result in positive patient outcomes.
A retrospective case control study of farm level risk factors for toxic mastitis was carried out in November and December 1996. Twenty-six farms from mid-Somerset were visited: 13 case farms (had had a cow with toxic mastitis in the previous year) and 13 geographically matched controls (no case of toxic mastitis). The farmers were interviewed and the buildings were examined. Information was collected on the type and quality of housing, usual milking routines, milk quality and mastitis prevalence in the previous year. All the data were collected on to pretested recording sheets and loaded into a database. Simple and complex analysis was done. The following variable were significantly (P < 0.05) associated with an increased risk of toxic mastitis in the simple analysis: housing cows in October rather than November; a low number of calving boxes per cow; a high proportion of cows with intermediate body condition and low herd bulk milk somatic cell counts (HBMSCC). In the final model low HBMSCC and a high proportion of cows with intermediate body condition remained significant. The authors conclude that, despite the small size sample, the results of this study are consistent, plausible and support the information from previous experimental and observational studies about the role of somatic cell counts in toxic mastitis.
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The dye Procion Red HE3B immobilized on agarose and available as Matrex Gel Red A is shown to bind citrate synthase and succinate thiokinase from a number of diverse organisms. Salt-gradient elution removes the enzymes in high yields and with substantial purification. The elution profiles follow a pattern similar to that of the molecular size variations of the enzymes.
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The inhibitor SAN 6706 [4-chloro-5-(dimethylamino)-2-(alpha,alpha,alpha,-trifluoro- m-tolyl-3(2H)-pyridazinone] has been used to study the synthesis of carotenes and xanthophylls during the conversion of etioplasts to chloroplasts in developing barley (Hordeum vulgare) shoots. SAN 6706 inhibits carotenoid synthesis and causes an accumulation of phytoene, but it is also a potent inhibitor of chloroplast electron transport. When developing barley is treated with SAN 6706, carotenoid synthesis is inhibited but total photosynthesis is unaffected. The ability of SAN 6706 to inhibit carotenoid synthesis becomes progressively less if etiolated shoots are illuminated for increasing lengths of time before treatment. During the greening of treated barley shoots only light-induced beta-carotene synthesis is immediately inhibited; xanthophyll synthesis is not affected until after about 8 hours. The hypothesis that SAN 6706 cannot enter the chloroplast but inhibits carotenoid synthesis from the cytoplasm is discussed, and the question as to whether there are not two separate groups of enzymes for the synthesis of carotenes and xanthophylls is considered.
Creatine phosphokinase (CPK) levels during two consecutive pregnacies of a patient whose sister had died of malignant hyperpyrexia have been investigated. The results are compared with CPK levels of serum obtained from apparently normal people at similar stages of pregnancy. The rise of serum CPK occurring as a result of labour was much more pronounced in the malignant hyperpyrexia suspect.
Twenty-four female undergraduates, 12 high on anxiety sensitivity and 12 low on anxiety sensitivity, were subjected to a hyperventilation challenge task. Physiologic and subjective measures of arousal and distress were obtained before, during, and after the hyperventilation challenge. Alternating between the eight 15-second intervals of hyperventilation, participants engaged in a heartbeat-tracking task for eight 10-second intervals to assess interoceptive acuity. Although the hyperventilation challenge produced phase main effects for physiologic arousal, and group and time main effects for subjective distress, there were no significant interaction effects. Results revealed no significant interoceptive acuity differences across the low and high anxiety sensitivity groups. However, subjective ratings of physiological sensations during hyperventilation were significantly greater for the high anxiety sensitivity group. Hierarchical multiple regression analyses revealed that anxiety sensitivity accounted for additional variance beyond trait anxiety in explaining subjective ratings of arousal and distress in this nonclinical sample in response to a hyperventilation challenge.
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In 1997, a nursing care model task group was formed to develop a framework to guide the development of the nursing care delivery system in a newly merged hospital corporation. A collective group of experienced and motivated nurses in the renal program met to develop an integrated renal nursing professional practice model. In addition it was recognized that a city-wide model involving the two acute care renal centres would be advantageous. The challenge was to clearly articulate the professional roles and relationships of nurses and nurse practitioner/clinical nurse specialists in a constantly changing environment. This process provided the opportunity to identify key trends influencing renal care and possibilities for changing practice. Networking across the corporations was enhanced, partnerships were formed, and a sense of value for the work that was being undertaken developed. The group's endeavours resulted in an integrated nursing professional practice model that emphasizes accountability and continuity and places value on therapeutic relationships. Another strength of the model is the acknowledgement of the collaborative nature of the multidisciplinary team. After two years of development, the model was implemented. A city-wide Renal Nursing Professional Practice Council has been established in order to provide leadership in evaluating the model. This will include assessing the success of implementation, impact on patient/family care, and collaborative rewards experienced by staff. Future planning will address the potential need for a multidisciplinary focus within the practice council.
The purpose of this paper is to report the results of a descriptive study undertaken to examine the scope of practice of five Masters-prepared nephrology nurse practitioner/clinical nurse specialists (NP/CNS) in a mid-size university teaching hospital program. Four of the NP/CNSs practised in three acute care sites, and one in the regional dialysis program. Impetus for the study came from two sources. First, a sixth person practising in the role was retiring and was not to be replaced. Second, the current three-site model for acute care was being transformed into a two-site model, thus creating opportunities to reduce variability in practice among the NP/CNSs. The study examined the activities of the NP/CNS role through the completion of a time documentation tool (TDT) by five nurse practitioners on each of 10 consecutive days of practice. The TDT was adapted from Ackerman's Model of Advanced Practice (1996). The model outlines five domains of practice for advanced practice nurses (APN): direct comprehensive care, support of systems, research, education, and publication and professional leadership. The NP/CNSs spent an average of 9.21 hours at work daily with a range of 8.6 to 10.3 hours. The TDT captured an average of 8.6 hours of working time with a range of 7.3 to 9.9 hours. An average of 72% of time was spent in clinical practice (range 64-83%). An average of 16% (range 11-20%) of time was spent in support of systems. Research (average 4%, range 3-7%), education (average 6%, range 3-16%), and publication and professional leadership (average 2%, range 0-6%) figured less prominently. The major activities performed within the clinical practice domain and the support of systems domain showed less variability across sites than was anticipated. The results of the study have helped the NP/CNSs and their management colleagues analyze and adapt the role to changing clinical requirements and economic realities.
The following article describes the process by which a group of acute care nurse practitioners sought to address the legal challenges of working beyond the traditional scope of nursing practice. It was necessary to establish mechanisms for communicating a diagnosis, as well as for ordering diagnostic tests, treatments and procedures. Medical directives were viewed as an approach to address components of practice involving controlled acts not authorized to nursing. The process of developing medical directives began with a description of the components of a medical directive. Algorithms were then developed based on the College of Nurses of Ontario's decision tree (Purvis, 1995) for the performance of procedures. These algorithms were broad and applicable across all clinical programs. The final step, required each nurse practitioner/clinical nurse specialist in collaboration with physician colleagues, to develop individual appendices specific to each clinical program. Health care administrators may find the information provided of assistance in addressing legal concerns that arise when new opportunities for nursing involve movement beyond traditional boundaries.