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Biomedical subjects

E C Cameron

Publications and source records attributed to E C Cameron.

At least 19 recordsLinked to original sources
PubMed2000

Evaluation of the effect of intravenous l-carnitine on quality of life in chronic hemodialysis patients.

AIM: The aim of this study was to determine the effect of l-carnitine on quality of life (QOL) in chronic hemodialysis patients. PATIENTS AND METHODS: This trial used a randomized, prospective, placebo-controlled, double-blind, crossover design. Inclusion criteria were patients who were older than 18 years, had been on dialysis for a minimum of one year, and had at least two of the following symptoms: intradialytic hypotension, muscle cramping, lack of energy, muscle weakness or myopathy, cardiomyopathy, or lack of responsiveness to erythropoietin (EPO). Patients were excluded if they were mentally incompetent to complete a QOL questionnaire. Sixteen patients were randomized to receive either l-carnitine (20 mg/kg) or placebo (normal saline) after each dialysis session for 12 weeks, followed by a 6-week washout, then the crossover therapy for 12 weeks. The Kidney Dialysis Questionnaire was the assessment tool used to evaluate QOL. RESULTS: There was no significant effect of l-carnitine on QOL irrespective of treatment order. There were also no differences found in any of the secondary outcomes including incidence of muscle cramping, intradialytic hypotension, EPO requirements or hemoglobin. Adverse effects consisted of gastrointestinal symptoms, with a similar incidence between l-carnitine and placebo. CONCLUSION: L-carnitine did not have a benefit on QOL in our patient population.

Aged↗
PubMed1994

Magnesium deficiency: pathophysiologic and clinical overview.

Magnesium is an essential cation, involved in many enzymatic reactions, as a cofactor to adenosine triphosphatases. It is critical in energy-requiring metabolic processes, as well as protein synthesis and anaerobic phosphorylation. Serum Mg concentration is maintained within a narrow range by the kidney and small intestine since under conditions of Mg deprivation both organs increase their fractional absorption of Mg. If Mg depletion continues, the bone store contributes by exchanging part of its content with extracellular fluid (ECF). The serum Mg can be normal in the presence of intracellular Mg depletion, and the occurrence of a low level usually indicates significant Mg deficiency. Hypomagnesemia is frequently encountered in hospitalized patients and is seen most often in patients admitted to intensive care units. The detection of Mg deficiency can be increased by measuring Mg concentration in the urine or using the parenteral Mg load test. Hypomagnesemia may arise from various disorders of the gastrointestinal tract, conditions affecting Mg renal handling, or cellular redistribution of Mg. The gastrointestinal causes include the following: protein-calorie malnutrition, the intravenous administration of Mg-free fluids and total parenteral nutrition, chronic watery diarrhea and steatorrhea, short bowel syndrome, bowel fistula, continuous nasogastric suctioning, and, rarely, primary familial Mg malabsorption. The renal causes include Bartter's and Gitelman's syndrome, post obstructive diuresis, post acute tubular necrosis, renal transplantation, and interstitial nephropathy. Many therapeutic agents cause renal Mg wasting and subsequent deficiency. These include loop and thiazide diuretics, aminoglycosides, cisplatin, pentamidine, and foscarnet. Magnesium deficiency is seen frequently in alcoholics and diabetic patients, in whom a combination of factors contributes to its pathogenesis. Hypomagnesemia is known to produce a wide variety of clinical presentations, including neuromuscular irritability, cardiac arrhythmias, and increased sensitivity to digoxin. Refractory hypokalemia and hypocalcemia can be caused by concomitant hypomagnesemia and can be corrected with Mg therapy. The dose and route of administration of Mg in the treatment of hypomagnesemia is dictated by the clinical presentation, the degree of Mg deficiency, and the renal function.

Animals↗
PubMed1994

Renal microangiopathy in the primary antiphospholipid syndrome: a case report with literature review.

We report the case of a 52-year-old male patient with recurrent thrombosis from 'primary antiphospholipid syndrome' who developed renal microangiopathy. Despite anticoagulant therapy with coumadin, serum creatinine progressively increased from 398 to 592 mumol/l and platelets decreased to 43,000. The patient responded to high-dose methylprednisolone and aspirin and the renal function improved. A review of the literature disclosed 4 other cases of association between primary antiphospholipid syndrome and renal microangiopathy. The clinical characteristics of these cases are discussed.

Adult↗
PubMed1992

Lymphoproliferative disorders after renal transplantation in patients receiving triple or quadruple immunosuppression.

A retrospective review of 478 renal transplant recipients receiving cyclosporin A (CsA) was conducted to determine the incidence, relative risk, and outcome of lymphoproliferative disease after transplantation. Cases of neoplasm were identified by linking the computerized databases of the British Columbia (B.C.) Transplant Society and the B.C. Cancer Agency. B.C. Cancer Statistics for 1988 were used to determine relative risk. Patients were monitored for a total of 1,054 patient years with a mean follow-up time of 26 months (range, 0.1 to 63 months). A total of 334 patients were treated with triple immunosuppression (CsA), azathioprine, and prednisone), and 144 received adjunctive antilymphocyte globulin as induction immunosuppression. Sixty-nine patients received OKT3 for the treatment of transplant rejection. Twenty-two patients developed 23 malignancies (4.8%) at a mean interval of 16 months (range, 3 to 45 months) after transplantation. Non-Hodgkins lymphoma occurred in five patients, of whom two received triple (0.6%) and three received quadruple (2.1%) therapy. All five patients, in addition, received OKT3 for the treatment of graft rejection. The relative risk of developing a neoplasm among the defined sample adjusted for age and sex was 3.08 overall, increasing to 26.9 (P less than 0.005) for lymphoma. Six of the 22 patients (27%), including all 5 patients with lymphoma, died as a result of their tumor. Renal transplant recipients receiving CsA have a significantly elevated risk of developing a de novo lymphoreticular malignancy, which is comparable to that reported for those receiving azathioprine treatment, and which appears to be increased by the use of quadruple immunosuppression and the administration of OKT3 for the treatment of acute graft rejection.

Actuarial Analysis↗
PubMed1991

Cytomegalovirus epididymitis following renal transplantation.

Cytomegalovirus infection is an important cause of morbidity and mortality in immunocompromised individuals. The disease is usually systemic in expression although localized infection can occur, particularly in the lung, liver, retina and gastrointestinal tract. We report a case of cytomegalovirus epididymitis with limited systemic manifestations occurring 2 months after renal transplantation in a patient immunosuppressed with azathioprine, prednisone and cyclosporine. Diagnosis was confirmed by observation of typical cytopathic changes in epididymal cells. Clinical resolution occurred with epididymo-orchiectomy and 9-(1,3-dihydroxy-2-proproxymethyl)guanine therapy. To our knowledge this presentation has not been described previously in the transplant literature and it is extremely rare in other forms of inherited or acquired immune deficiency.

Antiviral Agents↗
PubMed1991

The quality of initial function following renal transplantation determined by creatinine elimination kinetics. Comparison of Minnesota antilymphocyte globulin and cyclosporine induction immunosuppression.

To compare the effect of type of induction immunosuppression on the quality of initial renal allograft function, we identified 35 cadaver donor kidney pairs in which one recipient of a kidney from a given pair received induction immunosuppression with Minnesota antilymphocyte globulin (MALG group) while the recipient of the contra-lateral kidney received cyclosporine from day zero (CsA group). In the absence of an existing quantitative measure to assess and compare the status of those grafts that function primarily, we defined the half-life of creatinine elimination (t1/2SCr) as such an outcome measure based on a review of creatinine elimination kinetics. All organs were procured with in-situ perfusion and en-bloc removal. Total cold storage times, rewarm times, and perioperative management were comparable for the two groups. In the MALG group, the mean t1/2SCr) was not different from that in the CsA group (1.38 +/- 0.96 days vs 1.35 +/- 1.2 days P = NS). Multiple regression analysis performed on the differences in recipient age, number of DR-B locus matches, total cold ischemia time, rewarm time, and central venous pressure at reperfusion of a given donor pair demonstrated no significant impact of any of these differences on the difference in t1/2SCr for the same pair set in this sample. The nadir of serum creatinine achieved in the first five days posttransplant was somewhat higher in the CsA group (234 +/- 131 mumol/L) as compared with the MALG group (200 +/- 132 mumol/L) but the difference was not significant. A similar nonsignificant trend was observed in the comparison of mean serum creatinine values at 30 days posttransplant (MALG group: 158 +/- 62 mumol/L vs. CsA group: 200 +/- 141 mumol/L). Only one of seventy recipients (CsA group) was dialyzed within the first 5 days posttransplant for an overall incidence of ATN of less than 2%. Fourteen of 35 (40%) recipients in both groups received treatment for acute rejection. The mean time to first treatment for acute rejection episode was shorter in the CsA group than the MALG group (10 +/- 8 days vs 23 +/- 24 days, P = 0.055). Graft survival at one year was not different for the two groups (92% vs. 87% for the MALG and CsA groups respectively, P = NS).(ABSTRACT TRUNCATED AT 400 WORDS)

Antilymphocyte Serum↗
PubMed1987

Ion-exchange resins as potential phosphate-binding agents for renal failure patients: effect of the physicochemical properties of resins on phosphate and bile salt binding.

The effect of resin type, degree of cross-linking, bead size, and surface area on the phosphate and bile salt binding characteristics of five strongly basic Dowex anion-exchange resins in the chloride form was studied. The maximum uptake of phosphate (expressed as uptake of phosphorus) from sodium phosphate solutions was 137, 82, 86, 138, and 76 mg of phosphorus per gram of dry Dowex resins XF 43311, XY 40013, XF 43254, XY 40011, and XY 40012, respectively. The presence of simulated gastric or intestinal fluids resulted in small but insignificant alterations in phosphorus uptake by the resins. The resins all bound similar amounts of phosphorus and taurocholate (80-100% of the total phosphorus and taurocholate in solution) at physiological concentrations of phosphate and bile salt. Dowex resins XY 40013 and XF 43254, with identical physicochemical properties, but different bead sizes and surface areas, bound similar amounts of the bile salt sodium taurocholate at all taurocholate concentrations, indicating that binding was not restricted to the surface sites on the resin bead. The 2% cross-linked resins bound 3-4 times more taurocholate than the 8% cross-linked resins (at high taurocholate concentrations); the smaller pore size of the latter resins probably presents a greater mechanical exclusion barrier than the larger pore size of the 2% cross-linked resins.

Anions↗
PubMed1983

Drug treatment of primary hyperparathyroidism: use of clodronate disodium.

Clodronate disodium (dichloromethylene diphosphonate), a specific inhibitor of bone resorption, was given by mouth (1.0-3.2 g daily) to nine patients with primary hyperparathyroidism for two to 32 weeks so that its clinical and metabolic effects could be evaluated. Bone resorption decreased in all patients as judged by a fall in the fasting urinary calcium to creatinine and hydroxyproline to creatinine ratios. Serum calcium concentration was increased in all patients before treatment and fell in response to treatment to values near the upper end of the normal range. Hypercalcaemia and hypercalciuria recurred when treatment was stopped. In three patients treated for longer than 19 weeks clodronate failed to sustain the reduction in serum calcium concentration but the concentration remained below pretreatment values. These results suggest that clodronate may be of use in the medical management of primary hyperparathyroidism, particularly in patients in whom suppression of bone disease is desirable before surgery or in whom surgery is contraindicated.

Aged↗
PubMed1983

The use of dichloromethylene diphosphonate for the management of hypercalcaemia in multiple myeloma.

We have assessed the effects of the diphosphonate, dichloromethylene diphosphonate (Cl2MDP), in 19 patients with hypercalcaemia and increased bone resorption due to myeloma. Cl2MDP (800-3200 mg daily by mouth or 300 mg daily by intravenous infusion) decreased plasma calcium and biochemical indices of increased bone resorption in 16 of 19 patients. This effect persisted for the duration of treatment (up to 14 weeks). Prolonged treatment was associated with a progressive rise in serum alkaline phosphatase and only a transient fall in hydroxyproline suggesting the stimulation of bone repair. Since myeloma is associated with significant morbidity and mortality due to progressive bone loss, these results suggest that long-term treatment of myeloma with Cl2MDP is worthy of further study.

Aged↗
PubMed1983

Path analysis in genetic epidemiology: a critique.

Path analysis, a form of general linear structural equation models, is used in studies of human genetics data to discern genetic, environmental, and cultural factors contributing to familial resemblance. It postulates a set of linear and additive parametric relationships between phenotypes and genetic and cultural variables and then essentially uses the assumption of multivariate normality to estimate and perform tests of hypothesis on parameters. Such an approach has been advocated for the analysis of genetic epidemiological data by D. C. Rao, N. Morton, C. R. Cloninger, L. J. Eaves, and W. E. Nance, among others. This paper reviews and evaluates the formulations, assumptions, methodological procedures, interpretations, and applications of path analysis. To give perspective, we begin with a discussion of path analysis as it occurs in the form of general linear causal models in several disciplines of the social sciences. Several specific path analysis models applied to lipoprotein concentrations, IQ, and twin data are then reviewed to keep the presentation self-contained. The bulk of the critical discussion that follows is directed toward the following four facets of path analysis: (1) coherence of model specification and applicability to data; (2) plausibility of modeling assumptions; (3) interpretability and utility of the model; and (4) validity of statistical and computational procedures. In the concluding section, a brief discussion of the problem of appropriate model selection is presented, followed by a number of suggestions of essentially model-free alternative methods of use in the treatment of complex structured data such as occurs in genetic epidemiology.

Asian↗
PubMed1982

Dialysis encephalopathy and osteomalacic bone disease: a case-controlled study.

Nine patients on long-term hemodialysis with dialysis encephalopathy were studied, with sex matched control subjects for eight of the patients. Each patient with dialysis encephalopathy and control subject were contemporaries in a similar dialysis environment. Rib and other fractures were found in excess in the patients with dialysis encephalopathy (p less than 0.005 and p less than 0.01). These patients had less radiographic hyperparathyroid bone disease, and no more osteopenia as measured by metacarpal thickness than did their control counterparts. Severe osteomalacia was documented by bone biopsy in four of te patients. In a retrospective review of clinical, biochemical and pharmacologic differences, the patients with dialysis encephalopathy were significantly older at the start of dialysis (45.6 years versus 38.6 years, p less than 0.02) and had higher mean concentrations of blood urea nitrogen (BUN) and lower serum hemoglobin in the first year of dialysis than the control subjects. Blood pressure weight, creatinine, calcium, phosphate, alkaline phosphatase and a number of transfusions did not differ significantly. There was no difference in prescribed vitamin D and elemental aluminum in phosphate binders. This study demonstrates that patients with dialysis encephalopathy had more rib fractures without more parathyroid or osteopenic bone disease than did the control subjects and suggests that the etiology of dialysis encephalopathy and osteomalacia is multifactorial.

Adult↗