Search PubMed⌕ Search

Biomedical subjects

J D Harnett

Publications and source records attributed to J D Harnett.

11 recordsLinked to original sources
PubMed1991

Comparison of patients with idiopathic calcium phosphate and calcium oxalate stones.

Our primary objective was to test the hypothesis that a defect in acidification is more common in patients who have idiopathic calcium phosphate kidney stones than in those whose stones are formed mainly of calcium oxalate. Additionally, other risk factors might differ for these 2 stone types. Urine pH was measured serially over 24 hours, and along with ammonium and titratable acid, it was measured before and serially after ingestion of ammonium chloride in 3 groups of subjects: 24 patients with predominantly calcium phosphate stones, 30 patients with calcium oxalate stones, and 15 health non-stone-formers. Twenty-six parameters potentially related to stone formation and acidification were assayed on urines collected over 24 hours, and 15 parameters on blood. The data base was a computerized list of 5900 analyses of stones from patients living in Newfoundland. Patients not known by their physician to have had urinary tract infection, anatomical abnormality, hyperparathyroidism, or renal tubular acidosis were asked to participate in the study. Differences between means were considered significant if p values were less than 0.05 for F by analysis of variance and also less than 0.01 by t-test. In all patients with calcium oxalate stones and all non-stone-formers, urine acidified to pH less than 5.25, but in 8 of the 23 phosphate stone formers who completed the ammonium chloride study urine failed to acidify to pH less than 5.25. As all 8 had normal values for venous pH, total CO2, and chloride, they were considered to have incomplete renal tubular acidosis (IRTA). The 8 phosphate stone formers with IRTA had greater mean values for urine pH on all 9 specimens collected serially over 24 hours (all means greater than 6.2), and after administration of ammonium chloride (p less than 0.01), as well as lower mean values for urine titratable acid excretion (p less than 0.01), both after administration of ammonium chloride and in 24-hour urine samples, compared with the remaining phosphate stone formers whose urine acidified and the oxalate and non-stone-forming control groups. Nearly all the phosphate stone formers had 1 or more risk factors for stone formation, but with frequencies not significantly higher than those found in the oxalate group. Hypercalciuria and hypocitruria were the commonest, but increased oxalate or urate also occurred. Thus, idiopathic calcium phosphate stone formation can be associated with 1 or more of several risk factors, and, with the possible exception of those with IRTA, treatment should be similar to that given to patients with calcium oxalate stones.

Acidosis, Renal Tubular↗
PubMed1991

The natural history of myocardial disease in dialysis patients.

Among dialysis patients, only 23% have a normal echocardiogram, about 10% have recurrent or chronic congestive heart failure, and 17% have asymptomatic ischemic heart disease. The predisposing factors for congestive heart failure are dilated cardiomyopathy, hypertrophic hyperkinetic disease, and ischemic heart disease. Dilated cardiomyopathy, a disorder of systolic function, includes among its risk factors age, hyperparathyroidism, and smoking. Hypertrophic disease results in diastolic dysfunction, and its predictors include age, hypertension, aluminum accumulation, anemia, and, perhaps, hyperparathyroidism. Ischemic heart disease is due to the presence of coronary artery disease and also to nonatherosclerotic disease caused by the reduction in coronary vasodilator reserve and altered myocardial oxygen delivery and use. The clinical outcome of congestive heart failure is comparable to that of nonrenal patients with medically refractory heart failure. Left ventricular hypertrophy is an important independent determinant of survival. A subset have hyperkinetic disease with severe hypertrophy and have a bad survival, as low as 43% have a 2-yr survival after the first admission to hospital with cardiac failure. The prognosis for those with dilated cardiomyopathy is less severe but is worse than those with normal echocardiogram. The survival of patients with symptomatic ischemic heart disease was little different from that of patients without symptoms, suggesting that the underlying cardiomyopathies had an adverse impact on survival independent of ischemic disease. Much research needs to be undertaken on the risk factors, natural history, and therapy of the various types of cardiac disease prevalent in dialysis patients.

Cardiomegaly↗
PubMed1990

Outcome of congestive heart failure, dilated cardiomyopathy, hypertrophic hyperkinetic disease, and ischemic heart disease in dialysis patients.

Congestive heart failure in dialysis patients is associated with dilated cardiomyopathy, hypertrophic hyperkinetic disease and ischemic heart disease. To determine the natural history of these four diseases, 150 dialysis patients were prospectively followed for 3-5 years. The 2-year cumulative survival rate was 33% in those with recurrent or persistent congestive heart failure vs. 80% in dialysis patients without. Survival was significantly worse in patients with an echocardiographic diagnosis of dilated cardiomyopathy compared to patients with normal echo-cardiogram (2-year survival rate 67 vs. 90%). In hypertrophic hyperkinetic disease the 2-year survival rate was 30% after entry into the study, and 43% after first admission with congestive heart failure. Symptomatic ischemic heart disease did not have an adverse impact on mortality when compared to those without ischemic heart disease. We conclude that congestive heart failure in dialysis patients has a bad prognosis. Its associated disorders include dilated cardiomyopathy and hypertrophic hyperkinetic disease, the latter being associated with a high mortality. As the prognosis for patients with overt ischemic heart disease was not different from patients without, it is likely that the underlying cardiomyopathy directly influenced survival.

Cardiomegaly↗
PubMed1990

The clinical course of left ventricular hypertrophy in dialysis patients.

To determine the clinical and echocardiographic outcome of left ventricular hypertrophy a prospective study was undertaken of 104 nondiabetic dialysis patients without dilated cardiomyopathy, who were followed for 3-5 years. 33% of patients had normal echocardiogram, 41% mild and 27% severe hypertrophy (left ventricular wall thickness greater than or equal to 1.4 cm in diastole). In the first 2 groups 16% progressed to severe hypertrophy, 23% were admitted with congestive heart failure after starting dialysis therapy, and 2-year cumulative survivals were 97 and 85%. In the group with severe hypertrophy 88% already had severe hypertrophy on starting dialysis therapy, it was persistent in 87%, 50% were admitted at least once with congestive heart failure, and the 2-year cumulative survival was 53%. 71% of those who died in the severe group died from cardiac or cerebrovascular causes compared to none of those with normal echocardiogram, which accounted for the significantly worse (p = 0.001) survival. We conclude that severe left ventricular hypertrophy occurs frequently in dialysis patients, is often present at the start of end-stage renal disease therapy, is persistent, may predispose to congestive heart failure, and is associated with a high mortality.

Cardiomegaly↗
PubMed1989

The cardinal manifestations of Bardet-Biedl syndrome, a form of Laurence-Moon-Biedl syndrome.

To determine the interfamilial and intrafamilial variation in the expression of the Bardet-Biedl syndrome (a form of Laurence-Moon-Biedl syndrome), we looked for the five recognized features of the disorder (retinal dystrophy, obesity, polydactyly, mental retardation, and hypogonadism), plus possible renal manifestations, in some or all of 32 patients with this disorder. All 28 patients examined had severe retinal dystrophy, but only 2 had typical retinitis pigmentosa. Polydactyly was present in 18 of 31 patients, but syndactyly, brachydactyly, or both were present in all. Obesity was present in all but 1 of 25 patients. Only 13 of 32 patients were considered mentally retarded. Scores on verbal subtests of intelligence were usually lower than scores on performance tasks. Seven of eight men had small testes and genitalia, which was not due to hypogonadotropism. All 12 women studied had menstrual irregularities, and 3 had low serum estrogen levels (1 of these had hypogonadotropism, and 2 had primary gonadal failure). The remaining women who were of reproductive age had endocrinologic evidence of reproductive dysfunction. Diabetes mellitus was present in 9 of 20 patients. Renal structural or functional abnormalities were universal (n = 21), and three patients had end-stage renal failure. We conclude that the characteristic features of Bardet-Biedl syndrome are severe retinal dystrophy, dysmorphic extremities, obesity, renal abnormalities, and (in male patients only) hypogenitalism. Mental retardation, polydactyly, and hypogonadism in female patients are not necessarily present.

Female↗
PubMed1989

Development of a health questionnaire specific for end-stage renal disease.

To compare the efficacy of various end-stage renal disease (ESRD) therapies valid and reproducible probes which measure well-being and are specific for ESRD are necessary. Four studies were undertaken to provide and test these probes. (1) 107 dialysis and 119 transplant recipients were interviewed to determine the prevalence of 24 physical symptoms. (2) A questionnaire was devised using 2 new indexes (a symptom scale derived from the first study using 12 symptoms and an affect scale comprising 12 emotions) and 6 indexes previously used in other chronic illnesses. Interobserver and intraobserver reproducibility was satisfactory. (3) Construct validity for the questionnaire was shown by interviewing 97 dialysis and 82 transplant patients in whom we hypothesized that physical well-being would be better in transplant patients. After age matching the transplant group was more active, with a higher objective quality of life and fewer physical symptoms than the dialysis group. (4) 63 stable dialysis, 67 stable transplant, 15 dialysis patients successfully transplanted in the intervening year and 5 failed transplanted patients were reinterviewed 1 year later to assess the responsiveness of the questionnaire. In the group who had recently been successfully transplanted both physical, affect and quality of life scores showed a major improvement following transplant. We conclude that this questionnaire is specific for ESRD, examines physical, psychological, and social well-being, is brief, easily administered, reproducible, has construct validity and is responsive to changes in therapy.

Adult↗
PubMed1988

Left ventricular hypertrophy in end-stage renal disease.

To determine the prevalence of left ventricular hypertrophy (LVH; left ventricular wall thickness greater than or equal to 1-2 cm in diastole) among end-stage renal disease (ESRD) patients and the most important risk factors that independently relate to LVH, 189 non-diabetic ESRD patients without dilated cardiomyopathy in two centres had echocardiography and full clinical review. 104 of 189 (55%) patients had LVH consisting of 52 of 83 (65%) patients on haemodialysis, 18 of 20 (90%) peritoneal dialysis patients and 34 of 86 (40%) transplanted patients. Using multiple logistic regression, the most important factors which independently related to LVH, in all patients studied, were dialysis as current ESRD treatment (p less than 0.001), followed by age (p = 0.008), hypertension as defined by number of blood pressure medications (p = 0.007), followed by high serum alkaline phosphatase which probably reflects hyperparathyroidism (p = 0.03). In a subset of patients with severe LVH (left ventricular wall thickness greater than or equal to 1.4 cm), a high serum alkaline phosphatase level was the best predictor of LVH (p less than 0.001), followed by high diastolic blood pressure (p = 0.004) and age (p = 0.02). In dialysis patients, the most important variable were age (p = 0.009) and high serum alkaline phosphatase (p = 0.03). In the transplant group, patients with LVH were taking significantly more antihypertensive medications than those without LVH (p = 0.002). This variable was the only predictor of LVH in the transplant group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Hepatitis B disease in dialysis and transplant patients. Further epidemiologic and serologic studies.

As hepatitis B virus (HBV) infection in renal transplant recipients is associated with a high incidence of progressive liver disease it may be inadvisable to transplant hemodialysis patients with hepatitis B antigenemia. To determine the natural history of HBV disease in hemodialysis patients, all 49 patients on hemodialysis treatment for at least 1 year, at 3 centers, who developed circulating hepatitis B surface antigen (HBsAG), were studied. A subgroup of these patients (n = 31) aged less than or equal to 50 years, followed for 55 +/- 6 months after detection of HBsAg was compared with 22 previously studied HBsAg-positive transplant patients followed for 81 +/- 9 months. Significantly more transplant patients developed chronic hepatitis defined biochemically (P less than .001) and none of the transplant patients became HBsAg-negative compared with 19% of the hemodialysis group. Taking difference in follow-up into account, mortality was significantly higher in the transplant recipients (P less than .005) following development of HBsAg antigenemia, and the mortality difference was attributable to deaths from liver disease. A total of 36 serum samples from 14 of the 22 HBsAg-positive renal transplant recipients was analyzed for hepatitis B e antigen (HBeAg), antibody to hepatitis D virus (anti-HD), and hepatitis B virus deoxyribonucleic acid (HBVDNA) concentration. No serum sample was anti-HD-positive. Twelve of the 14 patients were HBeAg-positive. Five patients became HBeAg-negative, 3 of whom developed aggressive liver disease. One HBeAg-negative anti-HBe-positive patient had progression of liver disease from asymptomatic carrier status to chronic active hepatitis (CAH). Of 14 patients, 9 developed progressive CAH. HBVDNA concentration was not diagnostic of disease activity on liver biopsy. However only 1 sample of 10 measured in 5 patients with nonprogressive disease had a level greater than 100 pg/L, compared with 9 of 17 in the group who progressed to CAH. During the interval when the liver histology progressed from asymptomatic carriage or chronic persistent hepatitis (CPH) to CAH, the HBVDNA concentration increased by greater than 10 times baseline in 4 of 5 patients who had serial samples, whereas this did not occur in 4 patients with nonprogressive disease. We conclude that the long-term outcome of hepatitis B infection in transplant recipients is significantly worse than in hemodialysis patients. Therefore it may be inadvisable to transplant HBsAg-positive hemodialysis patients.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗