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Biomedical subjects

J R Chapman

Publications and source records attributed to J R Chapman.

At least 73 records · Page 4Linked to original sources
PubMed1995

Renal dysfunction in acute rejection. Effect of HLA typing, therapy, and histology.

Acute rejection is a frequent cause of early graft dysfunction in renal transplantation, and serum creatinine is the most important measure of clinical response. However, there is little information on serum creatinine during rejection episodes. In this study, the determinants that might influence the clinical response of serum creatinine during acute rejection were evaluated in 96 renal transplant recipients with 100 episodes of biopsy-proven rejection, by univariate and multivariate analysis. The factors assessed for their influence on serum creatinine in acute rejection included: presence and severity of vascular or cellular rejection on biopsy, time taken to institute therapy, HLA mismatch, and the use of OKT3. The presence of vascular rejection on biopsy (n = 28) was a major determinant of impaired reciprocal area under the curve (AUC) of serum creatinine (P < 0.01), and was correlated with HLA-A and -B mismatch (r = 0.21, P < 0.05). Acute rejection associated with HLA-DR mismatch resulted in a more rapid increase of serum creatinine, a higher maximal creatinine, and a greater AUC creatinine (all P < 0.05). Treatment of acute rejection with OKT3 had a beneficial effect on AUC creatinine (P < 0.05) when compared with intravenous corticosteroids, by multivariate analysis. However, vascular rejection and HLA-DR mismatch had no effect on serum creatinine 1 year after transplantation. The biopsy cellular rejection score had no effect on AUC creatinine, although there was a modest effect on gradient of creatinine prior to biopsy. A minor adverse effect of delay in therapy of acute rejection could be demonstrated in the methylprednisolone-treated subgroup. In summary, HLA-DR mismatch and the presence of vascular rejection were the most important predictors of the severity of rejection assessed by the response of serum creatinine to treatment. Appropriate antirejection therapy should be instituted promptly to optimize clinical response during acute rejection.

Adult↗
PubMed1995

Predicting glomerular filtration rate after kidney transplantation.

Serum creatinine is an important clinical measure of impairment of glomerular filtration rate (GFR) after kidney transplantation. The use of formulas that predict GFR (such as the Cockcroft-Gault) derived from patients with chronic renal failure and standardized against measured creatinine clearance may not be accurate when applied to kidney transplant recipients. The purpose of this study, was to investigate the level of inaccuracy and its causes and then to derive predictive GFR formulas that are appropriate to renal transplantation. Determinants of isotopic GFR, serum creatinine, and muscle mass were evaluated in consecutive kidney recipients (n = 146) using 99mTc DTPA GFR (n = 751) as a reference method. Factors that predicted GFR apart from serum creatinine included sex, height, body weight, serum urea, years on dialysis, numbers of rejections and infective episodes, and prednisolone dose. The relationship between serum creatinine and GFR was highly variable and dependent on factors that alter muscle mass and muscle catabolic rate. The relationship was further altered by ATN and chronic rejection when tubular secretion of creatinine was reduced. Three alternative GFR formulas (which can be applied to renal transplant patients according to the availability of clinical parameters) were derived and tested against six published methods of GFR estimation. Our derived formulas had the highest correlation, no overall bias, least scatter of sum of squares, and least error at low levels of GFR. They represent a better estimation of GFR in kidney transplantation than published formulas, and would allow a standardized approach to the study of long-term renal dysfunction.

Adult↗
PubMed1995

An overview of transplantation in Australia.

Organ donation in Australia has permitted transplantation of the kidneys, heart, lung, pancreas, liver and cornea. Each of these programs has successfully provided life and rehabilitation to Australians with end-stage failure of one or more organs. The programs are supported by an infrastructure of donor coordinators, matching and allocation procedures and national co-operative registries, which record and publish the outcome of each form of transplant. Four national organizations work to promote transplantation: the Transplantation Society of Australia and New Zealand; the Australasian Transplant Coordinators' Association; the Australian Kidney Foundation; and the Australian Co-ordinating Committee for Organ Registries and Donation. Australian donation rates are lower than in many, but not all, comparable developed democracies, however utilization of those donor offers is high, leading to 698 organ transplants being performed in 1993.

Australia↗
PubMed1995

The identification of potential cadaveric organ donors.

Most Australian transplantation programs are severely restricted in their activities by a limited availability of cadaveric donor organs. To investigate possible reasons for this problem, an audit was undertaken over three 12-month periods of all deaths in 13 hospitals in New South Wales and the Australian Capital Territory. From 7406 deaths, 271 patients were classified as having been realistic, medically suitable potential donors. Of these, only 60 (22%) became actual donors. In the other 211 patients, donation did not occur because of unsuccessful resuscitation (30%), permission refusal by relatives (34%), and failure to identify or support the potential donors (36%). If the impediments to organ donation which were identified in this study could be overcome, allowing a greater number of potential donors to become actual donors, the chronic shortage of cadaveric donor organs for transplantation could be at least partly relieved.

Brain Death↗
PubMed1995

Obtaining consent for organ donation in nine NSW metropolitan hospitals.

Organ donation rates vary markedly around the world. In an attempt to analyse why some patients' families are not asked about organ donation, the case notes of 6080 patients who died over a twelve-month period from April 1991 to March 1992 in nine hospitals in Sydney, NSW, were studied. Irreversible coma occurred in 515 patients. Of these, 177 were considered to be potentially brain dead donors, 126 of whom had a formal diagnosis of brain death. The clinicians caring for the patients at the time of death were asked at follow-up about the reasons for not considering donation, or the reasons for family refusal. Consent to proceed to organ donation was requested in 112 cases (49 donated and 63 refused) and not requested in 65. Analysis of the proportions asked and consenting in each hospital revealed no correlation. Half of the families refusing gave no reason (24/50) while eleven gave religious or cultural reasons, and six expressed a desire to prevent mutilation of the body as their primary reason for not consenting. There was universal failure to gain consent from families when the patient was not in an Intensive Care Unit. Analysis of those patients of whom consent was not sought showed that they died more quickly after admission, were older and died from causes other than trauma or intracranial haemorrhage. The odds of the family being asked dropped by about half as the age increased from one group to the next.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

A survey of families of brain dead patients: their experiences, attitudes to organ donation and transplantation.

A questionnaire survey of 69 families of brain dead patients is reported. The study population included those who had been asked about organ donation as well as those who had not, those who had agreed to organ donation and those who had declined. Their experiences and their perceptions of treatment and explanations of underlying disease, brain death and organ donation were examined. Their own knowledge of and attitudes towards organ donation as well as the prior knowledge and wishes of their deceased relative were also explored. Statistical analysis did not show any differences between the three groups of families with regard to their experiences, their perceptions of the treatment they received, or in the resolution of their grief. Family members who had agreed to organ donation were significantly more likely to donate their own organs and to be more resolved in their grief. There was a strong correspondence between the attitudes of respondents and their agreement or otherwise to donate their relatives' organs. One quarter, however, made the opposite choice for their relative, where their relative's wishes were known. There was a highly significant relationship between those who had previously discussed organ donation to have expected to be asked or to raise the subject themselves. Hospital treatment in general did not appear to have any effect on the decision to donate. Involvement in organ donation was felt by most of the donor families to have been helpful to the grieving process.

Adult↗
PubMed1995

Can cadaveric organ donation rates be improved?

There are many reasons why potential cadaveric organ donors may fail to become actual donors. These include permission refusal by the next of kin, incorrect assumptions about medical suitability and, occasionally, an excessive workload in the intensive care unit. Some potential donors currently regarded in Australia as "unrealistic" might become actual donors if attitudes were to change towards ventilation of patients with a clearly hopeless prognosis who have expressed a wish to be organ donors. "Required request" legislation ignores the wishes of the potential donor and "presumed consent" laws also present some ethical difficulties, but a suggested "required response" process could ensure that an individual's wishes concerning organ donation would be known and able to be carried out after death. For the present, however, it is clear that operating within existing Australian legislation and abiding by currently accepted codes of practice, we can still find considerable scope for improving cadaveric organ donation rates.

Age Factors↗
PubMed1995

Predicting glomerular filtration rate after simultaneous pancreas and kidney transplantation.

Impairment of glomerular filtration rate (GFR) after simultaneous pancreas and kidney (SPK) transplantation is an important marker of chronic renal rejection and recurrence of diabetic glomerulopathy. The use of unmodified serum creatinine to estimate GFR, however, is limited by variations in muscle mass. In this study, predictive factors for long-term GFR were evaluated in consecutive SPK recipients (n = 33) using a Tc99m DTPA GFR reference method between 90 days and 6 years after transplantation (n = 136 measurements). Substantial variability between serum creatinine and isotopic GFR after SPK (R2 = 0.30) high-lighted the inaccuracy of an unmodified serum creatinine in the evaluation of GFR. Factors which predicted GFR apart from serum creatinine included age, sex, height and body weight. A detailed formula was derived for accurate estimation of GFR (ml/min) = [71.4 (male) or 50.4 (female)] + 5520/creatinine (mumol/l) + 0.27 x body weight (kg) - 0.50 x age (yr) - 0.29 x height (cm). This formula was more accurate in estimation of GFR in SPK recipients than six published predictive methods which were derived from chronic renal failure patients using creatinine clearance. All of these methods overestimated GFR at lower levels of renal function. Most correlated poorly with Tc99m DTPA GFR and contained a generalized systematic overestimation of GFR which ranged from 4.7 to 8.4 ml/min (p < 0.05). A simplified version for rapid calculation was also derived as GFR (ml/min) = [25 (male) or 5 (female)] + 5000/creatinine (mumol/l).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Cost and effectiveness issues in care of injured patients.

Injury remains the leading public health problem in the United States in terms of cost and years of life lost. It is the number 1 cause of death and disability from birth to 44 years old, which is the most economically productive segment of our population. In the current environment of rapid-pace health care system reform at the state and national levels, trauma care systems have evolved at the forefront; regionalization, continuous quality improvement systems, designation/accreditation systems, registry databases, and cost-effectiveness evaluations are being implemented in many states. In most states, these systems remain immature, but the critical framework is in place. This article attempts to present the current state of cost of injury and effectiveness data, the status of trauma registries, and the evolution of functional outcome research in trauma care.

Health Status Indicators↗
PubMed1995

Erythrocytosis after renal transplantation: risk factors and relationship with GFR.

Post-transplant erythrocytosis (PTE) has been increasingly recognized as a complication of kidney transplantation, and several risk factors have been defined. Recent evidence suggests renal function may also play a role in hematological recovery after transplantation and risk of PTE. In this study of kidney transplant recipients (n = 123), simultaneous Tc99m DTPA GFR (n = 710) and hemoglobin levels were compared with possible clinical determinants. The frequency histogram of post-transplant hemoglobin was bell-shaped and continuously distributed above and below the arbitrary definition of PTE, suggesting that PTE is not a separate disease entity. Hemoglobin reached a plateau at 12 months after transplantation and was correlated with isotopic GFR (r = 0.46, p < 0.001). This consistent and statistically independent relationship became prominent 3 months after transplantation. Hemoglobin was independently predicted by multivariate analysis by time after transplantation, presence of polycystic renal disease, greater serum albumin and reduced serum urea (which in turn were reflected by number of infective and rejection episodes), shorter kidney anastomosis time and a higher GFR, but not by immunosuppressive therapy. Rejection or infection episodes impaired hematological recovery. The independent determinants of GFR included hematological recovery. The independent determinants of GFR included hemoglobin level, kidneys from young, male donors, fewer HLA-DR mismatches and rejection episodes, shorter time on dialysis and greater azathioprine dose. Renal function was not altered by therapeutic phlebotomy. Determination of hemoglobin level by both donor and recipient variables supports the relevance of tubular and glomerular function in control of erythrocystosis after renal transplantation. A role for renin-angiotensin mediation in the alteration of intraglomerular hemodynamics and erythropoietin secretion is postulated.

Adult↗
PubMed1994

Diagnostic utility of whole blood cyclosporine measurements in renal transplantation using triple therapy.

Whole blood CsA concentrations measured by specific monoclonal RIA (CYCLO-Trac SP whole blood RIA, IncSTAR) were compared with episodes of renal dysfunction (n = 138) and protocol biopsies (n = 52) that occurred within the first 100 days in consecutive renal allograft recipients receiving triple therapy (n = 92). Histological confirmation of events was available in 98% episodes of acute rejection (n = 60/61), 59% of episodes of CsA nephrotoxicity (22/38), and 100% of the diagnoses of acute tubular necrosis (35/35). Mean, minimum, and maximum CsA levels were elevated in CsA nephrotoxicity compared with all other groups (P < 0.001). Interestingly, CsA levels achieved relative to administered dose also increased at the time of CsA nephrotoxicity compared with other groups (P < 0.01). In the context of acute dysfunction, the sensitivity and specificity of mean CsA levels above 400 ng/ml to predict CsA nephrotoxicity were 32% and 89%, respectively. The negative predictive value of a high CsA level to exclude acute rejection was 88% (at 400 ng/ml), 92% (450 ng/ml), and 95% (500 ng/ml). As a marker of effective immunosuppression, CsA levels were not correlated with in vitro proliferation of PHA-stimulated PBL and did not reduce the severity and degree of cellular infiltration in needle core biopsies during rejection. The sensitivity and specificity of a low CsA level (150 ng/ml) in the diagnosis of acute rejection were 31% and 91%, respectively. The majority of episodes of acute dysfunction, including 63% of CsA nephrotoxicity and 59% of acute rejections, occurred with CsA levels between 150 and 400 ng/ml. In summary, when using low dose triple therapy regimens, CsA levels within the range of 150-400 ng/ml were of little diagnostic value in acute allograft dysfunction. In contrast, levels outside this range were useful in the clinical diagnosis of CsA nephrotoxicity and acute allograft rejection.

Adolescent↗
PubMed1994

Renal graft thrombosis. A survey of 134 consecutive cases.

Despite overall improved graft survival, renal graft thrombosis (RGT) remains an important cause of graft loss. Of 6153 consecutive renal transplants (RTx), 134 index cases of graft loss from RGT were reported to the Australian and New Zealand Dialysis and Transplant Registry between 1980 and 1992. Two groups were selected for comparison: (1) institutional controls (n = 127), the previous RTx at the same institution as each index case; and (2) graft controls (n = 107), the contralateral cadaveric donor kidney of each index case. RGT cases that coincidentally occurred in control groups were deleted from those groups (6 of institutional controls, 2 of graft controls). RGT within the first 30 days after RTx occurred in 1.9% of all RTx and was constant from 1980 to 1992. In contrast, RGT caused an increasing proportion of early (within 30 days of RTx) graft losses (P = 0.01). The cumulative occurrence of RGT in those who thrombose was 62.6%, 83.7%, 90.2%, and 93.5% at 2, 7, 14, and 30 days after RTx, respectively. By comparison, with the control groups, no association with RGT was demonstrated for recipient age or sex, primary renal disease, type of dialysis, treatment with CsA, degree of HLA mismatch, panel reactive antibody levels, perfusion solution and perfusion technique, or immunosuppressive therapy. There was a significantly increased incidence of RGT with both extremes of donor age, female donors, and prolonged total ischemic time.

Adolescent↗
PubMed1994

Thoracolumbar spine fractures with neurologic deficit.

The prognosis of patients with thoracolumbar spine fractures and neurologic deficits has improved in terms of survival and quality of life since principles of timely fracture reduction, decompression, and stabilization have been implemented. In patients with incomplete spinal cord injuries, acute intervention has been shown to lead to improved neurologic recovery rates. The type of surgical treatment and timing depends upon the fracture type and neurologic status of the patient.

Bed Rest↗