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J P Isbister

Publications and source records attributed to J P Isbister.

At least 19 recordsLinked to original sources
PubMed2001

Therapeutic apheresis.

During the last 30 years in vivo blood cell separation, generally referred to apheresis, has established a central role in both blood donor programmes and therapeutics. The technological advances in apheresis equipment has made procedures safer, faster and more effective. This article will review the use of apheresis in clinical medicine with emphasis on plasma exchange and peripheral blood stem cell collection. Plasma exchange now has a pivotal role in the management of a range of disorders, specially those with autoimmune pathogenesis. However, Plasma exchange should be practised as one component of an integrated and frequently multidisciplinary approach to management. The harvesting of allogeneic or autologous of peripheral blood haemopoietic stem cells is increased and it has become the principle indication for apheresis in many haematology units. A well coordinated protocol approach to this procedure is important if adequate haemopoietic stems cells are to be collected and safely cyropreserved. This requires successful cooperation between medical, nursing and scientific personnel.

Antigens, CD34↗
PubMed1997

Physiology and pathophysiology of blood volume regulation.

Adequate cardiac output and tissue perfusion is dependent on intravascular blood volume and its adequate return to the heart. Considering the overall functions of the cardiovascular system in ensuring appropriate flow to the peripheral microcirculation, it is not surprising that conflicts of interest may occur when an organism is exposed to stresses. Of particular importance are the stresses in which there are increased oxygen demands, decreased oxygen availability and concomitant requirements for thermoregulation. When there is depletion of intravascular blood volume, the splanchnic circulation is in effect an "autologous blood bank" for maintaining venous return until trans-capillary refill and haemodilution occurs. With the acute haematological stress response centralisation of blood, secondary contraction of the venous capacitance occurs, as seen with acute hypoxia. This results in overfilling of the heart, activation of atrial volume receptors, release of atrial natriuretic peptide and subsequent reduction of the plasma volume by rapid shifting of plasma into the lymphatic capacitance (via spleen) and transcapillary efflux throughout the circulation. In this overview the physiology and pathophysiology of blood volume, red cell mass and plasma volume regulation is reviewed.

Adaptation, Physiological↗
PubMed1997

Cytapheresis: the first 25 years.

In vivo blood cell separator technology was originally developed in response to a perceived need for granulocytes for septic neutropenic patients. This impetus led to the development of a variety of cell separators which, paradoxically, ultimately have found their main applications in pheresis procedures other than granulocyte collection. In vivo blood cell separators are ideal for the removal of large numbers of normal or abnormal hemopoietic cells. Their early use in chronic myeloid leukemia demonstrated that leukapheresis could be used as definitive therapy for the disease. However, most hematological diseases in which the circulating malignant cells can be pheresed off have definitive and cost effective standard of care therapies, and cytapheresis is limited to specific circumstances. This paper reviews therapeutic cytapheresis and summarizes the current status of its limited specific indications.

Blood Viscosity↗
PubMed1997

Cytapheresis--the next 25 years: stem cell therapy.

Hemopoietic stem cell transplantation therapy has firmly established a role in the management of a range of malignant and nonmalignant disorders. Allogeneic bone marrow transplantation has been used as an adjunct in the treatment of acute leukemia with impressive results that have translated into long-term survival and cure. This experience has now extended to the management of other hematological malignancies and some solid tumors. With the ability to source hemopoietic stem cells from the peripheral blood by in vivo cytapheresis, there has been a rapid growth in the use of this form of therapy. The risks and benefits must be clearly appreciated and appropriate resources available with associated monitoring and quality assurance. There are few areas of medicine for which such close cooperation is necessary between medical, nursing, scientific, and allied health professionals to achieve successful outcomes. This paper addresses the logistical aspects of the provision of hemopoietic stem cell therapy in a routine clinical setting.

Antigens, CD34↗
PubMed1996

What's new in clinical transfusion practice.

Although the Australian blood supply is among the safest in the world, homologous transfusion is not risk-free. In some circumstances, alternatives are available or being developed. Clinicians need to be aware of the risks, benefits and options in transfusion therapy and to fully inform patients of these.

Blood Preservation↗
PubMed1995

Activated protein c resistance (APC) and inherited factor V (FV) mis-sense mutation in patients with venous and arterial thrombosis in a haematology clinic.

BACKGROUND: Inherited factor V (FV) mis-sense point mutation has recently been identified as a major cause of familial venous thrombosis. The incidence of this congenital haemostatic disorder in Australia is unknown. AIM: To examine the incidence of this congenital defect in patients with thrombosis attending a haematology clinic. METHODS: Individuals investigated or treated for venous and arterial thrombosis over a four month period, as well as those who were on anticoagulant for valvular replacement or arrhythmia were studied for the presence of FV mis-sense point mutation, FV Q506 (G to A at nucleotide position 1691) by a polymerase chain reaction based test, and activated protein C (APC) resistance using an APTT based coagulation assay. RESULTS: Forty-five patients with venous thromboembolism (VTE), 20 patients with coronary artery disease and 25 patients with valvular replacement or arrhythmia who were on anticoagulant were examined. The frequency of FV mis-sense point mutation in these three groups was 26.7%, 15% and 4% respectively. In this study, patients with FV Q506 were of a younger age and had a higher incidence of extensive thrombosis or recurrence as compared to those with the normal factor V gene. This mutation was found in a diverse group of people (four of the 12 patients were of non-European origin). Nearly 50% of these patients had other risk factors for VTE. The number of patients with a family history of VTE was similar for those with the FV mutation and the normal FV. CONCLUSION: This study confirms the high incidence of FV Q506 mutation in patients with VTE reported overseas. Several clinical features, i.e. young age of onset of VTE, high recurrence rate, diverse ethnic background and importance of associated risk factors are highlighted. The findings in this study also raise the possibility that this mutation may be a risk factor for arterial thrombosis. Large studies are required to substantiate these findings.

Adult↗
PubMed1994

The clinician's approach to the management of risk.

Although risk has always been accepted as an integral part of any medical or surgical therapy, it is only in recent years that quantitation of this risk in transfusion medicine is being assessed in a detailed and practical manner. Balancing of the risk/benefit equation in relation to blood component therapy has only become a day-to-day issue in clinical medicine since the recognition that HIV could be transmitted by blood transfusion. Blood transfusion has never been as safe a procedure as most patients and clinicians have thought, with numerous potential complications and new ones being recognized. As medical teaching in blood component therapy has not had a high profile in most undergraduate and postgraduate medical curricula, there has been an inappropriately low level of awareness for the indications for the risks and benefits of blood component therapy. Since the appearance of transfusion-transmitted HIV, clinicians and patients alike have rapidly become aware of the potential risks associated with transfusion medicine. This paper addresses the issues of how the clinician can minimize the risks of blood component therapy and to effectively present the risks and benefits to clinical users and potential recipients of blood component therapy. Paradoxically, in developed countries, transfusion therapy is probably safer than it has ever been in the past, but the perception of the community is the opposite. Why is this so?, and what can be done to improve that patient's perception and associated fear? The ultimate answer rests with improving assessment of risks versus benefits, effective education and communication with the patient (and relatives) in order to achieve meaningful informed consent.

Blood Transfusion↗
PubMed1994

Haematological parameters. What to order and why.

With the enormous range of laboratory investigations available from a modern haematology laboratory it is not surprising that a clinician may at times feel 'at sea' when finding a way through the diagnostic process. It is hoped that this 'haematological map' will help the busy clinician.

Algorithms↗
PubMed1993

Adverse reactions to plasma and plasma components.

Since the early days of plasma fractionation, plasma and derivatives have been identified as being responsible for a spectrum of mild to life-threatening reactions, but it is increasingly being recognised that plasma and its derivatives may be responsible for a wider range of reactions in recipients and more frequently than is commonly appreciated by clinicians. These reactions may be related to immunological differences between the donor and the recipient, either with the component being antigenic to the recipient or the plasma containing an antibody reacting with a recipient antigen. Secondly, there may be physicochemical characteristics of the plasma component such as temperature, additives, alterations due to preparative process and accumulation of metabolites or cellular release products on storage. All of these may in some patients be responsible for clinically significant reactions. This review presents a broad overview of the clinical presentations of recipient reactions due to plasma or plasma components and their underlying mechanisms. Unless there is an immediate or acute fulminant reaction to the infusion of plasma component, adverse effects of these blood products frequently go unrecognised and untreated. Some of the reactions, if undiagnosed, may have a significant effect on the outcome of the patient. There are also various preventative measures which may be taken in the preparation of blood products or their administration to minimise their potential adverse effects.

Blood Component Transfusion↗