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Biomedical subjects

A Bradshaw

Publications and source records attributed to A Bradshaw.

At least 19 recordsLinked to original sources
PubMed1999

Disruption of the Sparc locus in mice alters the differentiation of lenticular epithelial cells and leads to cataract formation.

SPARC (secreted protein acidic and rich in cysteine) is a matricellular protein that regulates cellular adhesion and proliferation. In this report, we show that SPARC protein is restricted to epithelial cells of the murine lens and ends abruptly at the equatorial bow region where lens fiber differentiation begins. SPARC protein was not detected in the lens capsule or in differentiated lens fibers. SPARC-null mice developed cataracts at approximately 3-4 months after birth, at which time posterior subcapsular opacities were observed by slit lamp ophthalmoscopy. Histological analyses of ocular sections from 3-month old animals revealed several microscopic abnormalities present in the SPARC-null mice but absent from the wild-type animals. Fiber cell elongation was incomplete posteriorly and resulted in displacement of the lenticular nucleus to the posterior of the lens. Nuclear debris was present in the posterior subcapsular region of the lens, an indication of the abnormal migration and elongation of either fetal or anterior epithelial cells, and the bow region was disrupted and vacuolated. In the anterior lens, the capsule appeared to be thickened and was lined by atypical, plump cuboidal epithelium. Moreover, anterior cortical fibers were swollen. Polyacrylamide gel electrophoresis of the epithelial, cortical and nuclear fractions of wild-type and SPARC-null lenses indicated no significant differences among the alpha-, beta-, and gamma-crystallins. Expression of alphaB-crystallin appeared similar in fiber cells of wild-type and SPARC-null lenses, although the distribution of alphaB-crystallin was asymmetric in SPARC-null lenses as a result of abnormal lens fiber differentiation. No evidence of atypical extracellular matrix deposition in areas other than the capsule was detected in wild-type or SPARC-null lens at 3 months of age. We conclude that the disruption of the Sparc locus in mice results in the alteration of two fundamental processes of lens development: differentiation of epithelial cells and maturation of fiber cells.

Animals↗
PubMed1998

Defining 'competency' in nursing (Part II): An analytical review.

The reason for the present uncertainty in defining nursing competency is analysed. The prevailing educational philosophy underpinning nursing preparation for competence is subjected to a critique. The effect and outcome of this philosophy on clinical supervision, PREP and the law are considered in relation to nursing competence. It is concluded that because nursing competency is only vaguely and broadly defined, preparation and assessment of competency is haphazard and unstructured; and hence a potential safety hazard for both patient and nurse. It is suggested that the UKCC needs to assume responsibility for ascertaining nursing competence; and a four-point framework is proposed for setting and testing national standards of nursing competency.

Clinical Competence↗
PubMed1997

Defining 'competency' in nursing (Part I): A policy review.

How the nursing profession in England defines the basic competency of the registered general nurse is crucial for the safety of the patient and the protection of the nurse. It is also essential for determining advanced practice, extended practice and specialist practice in nursing. An historical overview of documentation from the United Kingdom Central Council for Midwifery and Health Visiting, the English National Board for Nursing, Midwifery and Health Visiting and the Royal College of Nursing shows a profound change in educational policy during the 1980s regarding the interpretation of nursing competency. The effects of this policy change on the current methods developed to define, teach and test nursing competency are examined. Preliminary conclusions show shortcomings and uncertainty in the present preparation and evaluation of nursing competency.

Clinical Competence↗
PubMed1996

The spiritual dimension of hospice: the secularization of an ideal.

There is increasing concern that the original hospice ethos is becoming subject to routinization and bureaucratization. Authors, drawing on Weber's concept of rationalization, have suggested that this has resulted from the loss of the original charismatic impetus and the commitment to care for the terminally ill and dying as inspired by the spiritual 'calling'. This paper argues that this original ethical ideal has been fundamental to the humane care of the dying and terminally ill. Using Alasdair MacIntyre's analysis it is suggested that as the ideal attenuates there are inevitable shifts in the ethos and culture of care. An emotivist culture in which the aesthete, the therapist and the manager are dominant characters, may seem to be occurring in palliative care. The focus on management skills and the values of efficiency and effectiveness influence attitudes to death. This brings increased medicalization, a reliance on psychosocial techniques, a predominant focus on education, research and audit and most particularly redefined attitudes to the spiritual component of care. The paper asks the question whether the original ethic has a place in preventing palliative care becoming merely a technique for professional empowerment.

Empathy↗
PubMed1996

Yes! There is an ethics of care: an answer for Peter Allmark.

This paper is a response to Peter Allmark's thesis that 'there can be no "caring" ethics'. It argues that the current preoccupation in nursing to define an ethics of care is a direct result of breaking nursing tradition. Subsequent attempts to find a moral basis for care, whether from subjective experimental perspectives such as described by Noddings, or from rational and detached approaches derived from Kant, are inevitably flawed. Writers may still implicitly presuppose a concept of care drawn from the Judaeo-Christian tradition but without explicit recourse to its moral basis nursing is left rudderless and potentially without purpose. The very concept of 'care' cut off from its roots becomes a meaningless term without either normative or descriptive content.

Christianity↗
PubMed1995

What are nurses doing to patients? A review of theories of nursing past and present.

This paper looks critically at the nature of nursing theory from three perspectives. Firstly, it examines the current state of nursing theory with a particular focus on Patricia Benner's work. This examination concludes that nursing theory is currently beset by the problems of scientific and moral relativism and philosophical incoherence because it has abandoned a traditional realist approach to the care of patients. Secondly, the roots of this contemporary nursing position are analysed and the conclusion is reached that nursing theorists are implicitly presuming this traditional 'common sense' view of nursing, although their own philosophical assumptions do not support it and indeed are removing the ground from beneath it. The traditional theory underpinning the quality of the nurse's care, and hence the ethos of nursing, is rearticulated. In conclusion it is suggested that nursing needs to debate the modernist views that are now holding sway in nursing and rediscover a theory for the care of patients that holds together the personal, the pastoral, the scientific and the technological aspects of patient care.

Ethics, Nursing↗
PubMed1995

Effect of arterial cannulation and contrast agents on blood coagulation.

RATIONALE AND OBJECTIVES: Nonionic contrast media have been considered by some to have thrombogenic properties. We prospectively assessed the effect of femoral artery catheterization and both nonionic and ionic contrast media on the coagulation parameters--fragment 1 + 2 (F1 + 2) and fibrinopeptide A (FpA)--during clinical angiography. METHODS: Seventeen patients undergoing aortography were included. Blood samples were obtained before and after arterial puncture and before and up to 30 min after contrast administration. RESULTS: An increase in FpA was observed after arterial puncture (range = 8.4 +/- 1.9 to 13.6 +/- 2.3 ng/ml, p < .004; data are written as mean +/- standard error of the mean). There was an observed increase in F1 + 2 after arterial puncture that was not statistically significant (2.0 +/- 0.4 to 2.3 +/- 0.4 nmol/l). No further increase was observed in either FpA or F1 + 2 levels after nonionic or ionic contrast media administration. CONCLUSION: The increased activity of the coagulation system during angiography is related to the arterial puncture, and nonionic and ionic contrast media have no thrombogenic potential in vivo.

Adolescent↗
PubMed1994

Relationship between hemostatic abnormalities and neuroendocrine activity in heart failure.

Thromboembolism is an important complication of heart failure. To test the hypothesis that heart failure may be associated with hemostatic dysfunction, we studied hemostatic function in 21 patients with stable chronic heart failure and related these measures to the severity of heart failure as assessed by clinical evaluation, neuroendocrine activation, radionuclide ventriculography, and cardiopulmonary exercise testing. Plasma and blood viscosity were elevated; all patients showed evidence of platelet activation, and many had elevated plasma concentrations of fibrinopeptide A, D-dimer, and von Willebrand factor. The plasma concentrations of these variables were poorly interrelated and related poorly to the severity of heart failure. Plasma concentrations of angiotensin II and endothelin were correlated, and the latter was also correlated with the plasma concentration of von Willebrand factor. Patients with chronic heart failure have hemostatic abnormalities that may predispose them to thromboembolic events and may be in part due to neuroendocrine activation.

Adult↗
PubMed1993

The clotting issue: etiologic factors in thromboembolism. II. Clinical considerations.

RATIONALE AND OBJECTIVES: The authors analyze the origins of the "clotting issue," the controversy that began in the 1980s when contrast media, once perceived as good flushing agents for catheters because of their assumed anticoagulant properties, came under attack for allegedly causing thromboembolism. Laboratory studies as well as a number of clinical reports seemed to substantiate this charge. Nonionic agents in particular were accused by some clinicians of being more likely to cause clots to form in syringes contaminated with blood than were ionic agents. The authors wanted to determine whether some lapse in operator technique rather than a fault in the contrast agent might be to blame. The theory that the syringe and catheter materials, and not the contrast agent itself, could be the source of thromboembolic problems in angiography also is examined. METHODS: The authors reviewed studies and reports on both sides of the issue and conducted laboratory and clinical studies of their own. For the syringe materials analysis, they used a fibrinopeptide A (FpA) enzyme-linked immunosorbent assay (ELISA) test to monitor levels as a marker of activation of coagulation. They tested catheter materials using the same technique. RESULTS: Clots were found only in nonionic agents, but under nonclinically relevant circumstances. If the anticoagulant effect of the nonionic contrast agent was maximized by mixing rather than layering blood and agent, clots did not form. In their materials analysis, the authors demonstrated that glass syringes are thrombogenic, causing vigorous contact activation, and that plastic is less so. Polyurethane catheters are more thrombogenic, polyethylene less so. One survey conducted in the 1970s on the clinical incidence of thromboembolism in coronary angiography suggested that the single most important factor in the etiology is poor angiographic technique. The authors' studies supported their thesis. CONCLUSIONS: In terms of the findings from laboratory studies, misinterpretation of data by nonclinicians is one problem. No evidence suggests that nonionic contrast agents are in any way prothrombotic or thrombogenic. On the contrary, in line with their greater inertness, nonionic agents have weaker effects. Ionic contrast media may cause more endothelial injury and associated localized platelet deposition than nonionic contrast media, and more anticoagulant contrast agents are more toxic. If anticoagulation is required, therefore, it should be achieved by such procedures as carefully controlled systemic heparinization rather than by resorting to more toxic materials. The activation of coagulation is caused by endothelial injury and by prolonged contact between blood and foreign surfaces such as syringes or catheters, but is inhibited by the contrast agent. Because a thrombus may form inside the catheter, whatever contrast agent is used, flushing is important. The authors agree with the findings of one study that the incidence of thromboembolism in coronary angiography, and probably in other catheter procedures, is markedly operator dependent. The materials of the syringes and catheters used, as well as the state of the patient's intrinsic clotting, are more important factors than the contrast agent. The authors conclude that materials other than the contrast agents are the cause of thromboembolic problems; and that, being anticoagulant, contrast agents are entirely helpful, if variably so, in angiographic procedures.

Blood Coagulation↗
PubMed1991

Hemostatic studies in patients with infective endocarditis: a report on nine consecutive cases with evidence of coagulopathy.

Local and generalized changes in coagulation may be important in the genesis of vegetations and embolism in infective endocarditis. To characterize such alterations, serial hematological investigations were performed on nine consecutive patients who satisfied the inclusion criteria. Platelet survival was measured by Indium111 labeling. Acute and convalescent samples were analyzed for fibrinogen, factor VIIIc, antithrombin III (AT III), fibrin/fibrinogen degradation products (FDPs), and platelet aggregation. The results suggest that in the active stage of the disease: (1) hypercoagulability may be caused by a rise in acute phase reactants, (2) an acceleration of coagulation and fibrinolysis may supervene, and (3) in some cases there is a reduction in platelet aggregation, possibly as a result of continued circulation of previously activated "exhausted" platelets.

Adult↗
PubMed1989

Major surgery in von Willebrand's disease.

Two patients with von Willebrand's disease underwent major surgery, the first had aortic valve replacement and the second a total hip replacement. Clinically, the best practical test for monitoring the dose of cryoprecipitate necessary to maintain haemostasis was the bleeding time. The response to coagulation factor replacement in von Willebrand's disease is extremely variable, and it is necessary to maintain close coagulation monitoring until the patient's surgical condition is satisfactory for discharge from hospital.

Aged↗
PubMed1988

Prevention of stomal recurrence in patients requiring emergency tracheostomy for advanced laryngeal and pharyngeal tumors.

Since 1976, patients requiring emergency tracheostomy for advanced laryngeal and hypopharyngeal cancer at the University of Cincinnati have been treated with a short course of prelaryngectomy radiation in an attempt to decrease the incidence of stomal recurrence. Twenty-one patients were treated after emergency tracheostomy with a course of radiation that usually consisted of 20 Gy in five fractions followed by laryngectomy 1 or 2 days later. Most patients also received postoperative radiotherapy of some type. The follow-up of 18 evaluable patients revealed only two (11%) stomal recurrences--a quite acceptable rate for this high-risk population. Overall, however, local recurrences were seen in ten patients (56%), which is higher than reported in most series of similar tumors. The most likely explanation for this seems to be that the short course preoperative radiation prevented the administration of adequate postoperative radiation for residual disease, which was usually present. An alternative treatment policy would be a planned course of moderate- to high-dose postoperative radiation, which could sterilize tumor in the entire locoregional area including the stoma.

Aged↗
PubMed1988

Antenatally diagnosed subdural haemorrhage in congenital factor X deficiency.

The presence of a subdural haemorrhage was observed in a fetus during antenatal ultrasound examination. The infant was found to be a homozygote for factor X deficiency. Prompt recognition permitted replacement treatment from an early stage. Inherited coagulation disorders should be suspected when intracranial haemorrhage is detected antenatally.

Cerebral Hemorrhage↗