Biomedical subjects
A Mitchell
Publications and source records attributed to A Mitchell.
Unpicking NPC.
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Transcription. Dial S for silence.
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Haemodynamic characterization of young normotensive men carrying the 825T-allele of the G-protein beta3 subunit.
A C825T polymorphism was recently identified in the gene for the G-protein beta3 subunit, the T-allele being associated with hypertension. To better understand the underlying pathophysiological mechanisms, we compared the haemodynamics of young healthy males with and without the T-allele. In three studies, subjects were investigated with regard to cardiac and vascular function at rest and following intravenous administration of the beta-adrenoceptor antagonist, propranolol, and the alpha2-adrenoceptor agonist, alpha-methylnoradrenaline, and with regard to local venous vasoconstriction in the dorsal hand vein in situ following infusion of the alpha2-adrenoceptor agonist, azepexol. alpha2-Adrenoceptor agonists were chosen as vasoconstrictor drugs since alpha2-adrenoceptors couple to pertussis toxin (PTX)-sensitive G-proteins and since in-vitro studies have demonstrated enhanced signal transduction of PTX-dependent pathways in the presence of the T-allele. Total peripheral resistance was determined as a parameter of vasoconstrictor tone and heart rate, stroke volume and systolic time intervals for cardiac function. T-allele carriers had a significantly elevated stroke volume and lower total peripheral resistance at baseline. After propranolol, their fall in stroke volume was significantly greater. During alpha-methylnoradrenaline infusion, elevation of total peripheral resistance was not increased relative to controls. Similarly, the constriction response of the dorsal hand vein to azepexol was not different. Our study does not support the idea of increased vasoconstrictor tone in T-allele carriers either at rest or during stimulation of alpha2-adrenoceptors. However, this allele may be associated with elevated cardiac stroke volume.
Anaesthesia in a child with autosomal recessive omodysplasia.
A child with a recently described form of dwarfism, autosomal recessive omodysplasia, presented for general anaesthesia for dental conservation. Despite the patient's dysmorphic features and craniofacial and mandibular deformities, no significant anaesthetic problems were encountered. Anaesthetic implications of the condition are reviewed.
Endovascular treatment of renal artery stenosis.
Significant changes have occurred in the treatment of renal artery disease over the past few years. Although excellent clinical results can be obtained with surgery, percutaneous transluminal renal angioplasty has proved similarly efficacious and is now the treatment of choice for nonostial atherosclerotic stenoses and fibromuscular dysplasia. The introduction of stents has become a valuable adjunctive therapy for postangioplasty restenosis and dissection.
Isolation of genomic DNA from blood using a novel filter-based DNA purification technology.
A novel DNA purification technology is described that enables the purification of pure dsDNA from blood. When compared to existing DNA purification methods, the Whatman BioScience Purification System (WBPS) offers a fast and convenient way to recover high yields of DNA. WBPS is based on a unique filter system that entraps DNA within a matrix. This allows the process to be performed in a single unidirectional reaction vessel, reducing user interaction and multiple centrifugation steps.
Cost-effectiveness analysis and the consistency of decision making: evidence from pharmaceutical reimbursement in australia (1991 to 1996).
OBJECTIVE: The principle aim of this study was to generate a league table of drugs considered by the Australian Pharmaceutical Benefits Advisory Committee (PBAC) for reimbursement. The table was used to test the hypothesis that decisions made by the PBAC are consistent with the maxim of economic efficiency. In addition, we explored whether the past decisions by the PBAC revealed a threshold incremental cost-effectiveness ratio beyond which the PBAC is not prepared to recommend reimbursement of a drug. METHODS: All 355 submissions made to the PBAC between January 1991 and June 1996 were reviewed. Submissions using cost per life-year gained (26 submissions) or the cost per quality adjusted life-year (QALY) gained (9 submissions) were ranked in a league table and compared with advice given by the PBAC about that drug. The confidentiality restrictions for the submissions require that the individual drug details cannot be revealed in this article. RESULTS: There was a statistically significant difference between the cost per life-year gained for drugs that were recommended for listing and those that were not, suggesting that the PBAC has been broadly consistent with the use of economic efficiency as a criterion for decision making. We did not find an explicit threshold beyond which the PBAC was unwilling to pay for additional life years gained. However, between 1992 and 1996 the PBAC appears to have been unlikely to recommend a drug for listing if the additional cost per life-year exceeded 76 000 Australian dollars [$AU] (1998/1999 values) and was unlikely to reject a drug for which the additional cost per life-year gained was less than $AU42 000. The cost-effectiveness ratio was not the only factor determining the reimbursement decision. CONCLUSIONS: The results of this preliminary study indicate that decisions to recommend a drug for listing by the PBAC in the last few years have, by and large, been consistent with the notion of economic efficiency.
SNAP-shots: scenes from nursing action plans--the cultivation of leadership in oncology nursing.
PURPOSE/OBJECTIVES: To describe the experiences of oncology nurses who participated in a national workshop to prepare nurses to lead the transformation of cancer care and to illustrate the range of possibilities available to nurses motivated to affect positive change. DATA SOURCES: Literature on leadership and negotiation are referenced and related to the personal experiences and the observations of participants in the workshop. DATA SYNTHESIS: Leadership is presented in historical context. A case study approach was used to organize the personal accounts of participants' plans to affect positive organizational change in oncology care settings. Scenes from action plans illustrate how the workshop's core curriculum, which focuses on leadership models, processes, and skills, was realized in practice. CONCLUSIONS: Leadership is a dynamic process that shapes and is shaped by all stakeholders during the process of planned change. Education, risk taking, and active participation are vital components of the process of leadership development. IMPLICATIONS FOR NURSING PRACTICE: The contributions of nurses may be simple of complex and affect single individuals, groups, or institutions. In all cases, oncology nursing practice and cancer care may be enhanced.
Breast cancer audit: adapting national audit frameworks for local review of clinical practice.
OBJECTIVE: To assess the value of using a nationally devised data set for breast cancer audit at a local level for reviewing clinical practice. DESIGN: Audit proforma based on the Scottish Cancer Therapy Network (SCTN) minimum data set and database completed prospectively from January 1999. SETTING: Hairmyres Hospital, a district general hospital within Lanarkshire Acute Services NHS Trust. SUBJECTS: The inclusion criteria were those developed by SCTN for the core minimum data set for breast cancer (SCTN 1999). RESULTS: The results indicate that the SCTN minimum data set can be usefully employed to collect prospective data on breast cancer. The data set is sensitive enough to identify any problem areas, which can be reviewed at greater detail when required. This datset is a robust mechanism for collecting meaningful and comparable data both at a local and national level. CONCLUSIONS: The use of SCTN's minimum data set has been successful for local review of practice. This has led to the identification of "out-liers" from the normal range of process indicators and further internal examination of these at a local level by individual clinicians is under way. This exercise has also proved fruitful in identification of other fields, which can be added to the data set to refine the data collected. The database provided by SCTN is easily manipulated allowing for refinement where required. Breast cancer audit carried out in this way is a useful way of reflecting on clinical practice throughout the multidisciplinary team.
Problems in pharmacoeconomic analyses
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Absence of the left portal vein: a difficulty for reduction of liver grafts?
BACKGROUND: Absence of the portal bifurcation is exceptional and characterized by an absent extrahepatic portal vein bifurcation, the right portal vein only being at the porta hepatis. There is no extraparenchymal left portal vein. This may represent a problem in liver splitting, reduction, and living related transplantation. METHOD: A case was encountered during reduction of a cadaveric liver allograft to a left lateral segmental graft from a 40-kg cadaveric donor to a 15-kg recipient. The portal venous inflow was reconstructed with a vein graft via a novel extrahilar approach to the left portal vein at the umbilical fissure. RESULTS: This graft was used successfully in a 3-year-old child requiring transplantation for a failed Kasai operation for extrahepatic biliary atresia. The child is now well, 1 year posttransplant, after an uneventful postoperative course with good portal flow within the graft. CONCLUSION: The situation of an absent left portal vein extrahepatic course should not preclude splitting or reduction procedures. The innovative technical solution, we propose, should add to the armamentarium of the liver transplant surgeon contemplating a left lateral segmental graft for the paediatric liver transplant recipient.
En block combined reduced-liver and small bowel transplants: from large donors to small children.
BACKGROUND: The critical shortage of size-matched donor organs for infants and small children in need of combined liver and intestinal transplantation has lead to long waiting times and a high risk of dying before transplantation. Utilizing grafts from larger donors could alleviate this problem, but using larger composite grafts in small children has been challenging and unsuccessful in the past. METHODS: We conducted a pilot study for evaluating the results of transplanting into small recipients a composite graft (reduced-size liver and whole small bowel, including duodenum and pancreas head) procured from large donors. Liver size reduction was performed ex situ using the extrahilar approach, which leaves the liver hilum untouched. Straightforward implantation of the graft was performed by simple, two-step vascular anastomoses. The preservation of the donor duodenum in continuity with the combined graft avoided the need for biliary reconstruction, thus preserving maximal bowel length for gut continuity restoration in the recipient. RESULTS: Two children, weighing 7.6 and 9.8 kg, respectively, underwent transplantation of a composite graft procured from donors weighing 35 kg. Their waiting time (68 and 97 days, respectively) was shorter compared with our previous experience with conventional techniques. Both are currently alive and well, at home and on full enteral feeds, 15 and 11 months after transplantation, respectively. CONCLUSION: This new technique has extended the range of possible donors for small candidates waiting for combined grafts and was successful in two patients. It should be considered for small recipients in the future.