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Biomedical subjects

H R Harter

Publications and source records attributed to H R Harter.

At least 19 recordsLinked to original sources
PubMed1987

Exercise training reduces depression and increases the performance of pleasant activities in hemodialysis patients.

This study compares the effects of a structured exercise training program to the therapeutic benefits of a 'support' group on the depressed mood and reduced performance of pleasant activities by hemodialysis patients. After 6 months of an aerobic exercise training program, the 10 exercisers showed a significant increase in maximal aerobic capacity (VO2max) and a significant decrease in dysphoric mood when compared to 7 patients attending the support group. Support group participants reported a significant decrease in pleasant activities while there was no change in the exercisers. Eighteen months after the exercise training program, the exercisers reported continued low levels of depressed mood, and were performing significantly more pleasant activities than they reported prior to the exercise program. The results of this study suggest an exercise training program may be useful in the psychosocial rehabilitation of some hemodialysis patients.

Activities of Daily Living↗
PubMed1986

Comparison of the effects of prazosin versus propranolol on plasma lipoprotein lipids in patients receiving hemodialysis.

A prospective, crossover study was used to evaluate the effects of prazosin and propranolol on lipid metabolism in 10 hypertensive patients receiving long-term hemodialysis therapy. Adequate blood pressure control was achieved with either agent (mean predialysis blood pressure was 144/77 mm Hg). Total triglyceride levels increased by 27 +/- 4 percent during propranolol therapy but decreased during prazosin therapy by 8 +/- 2 percent (p less than 0.05). These changes were accounted for by a 21 +/- 1.5 percent increase in very-low-density lipoprotein triglyceride during propranolol therapy and a 6 +/- 2 percent decrease in very-low-density lipoprotein triglyceride during prazosin therapy (p less than 0.05). Although no change in total cholesterol occurred with either agent, a significant decrease (19 +/- 1 percent, p less than 0.01) in high-density lipoprotein cholesterol occurred with propranolol therapy and an increase of 16 +/- 4 percent occurred during treatment with prazosin (not significant). The high-density lipoprotein2 cholesterol levels decreased by 22 +/- 4 percent after treatment with propranolol and increased by 4 percent after prazosin therapy. Propranolol reduced high-density lipoprotein3 cholesterol levels by 18 +/- 2 percent, whereas prazosin increased these values by 19 +/- 2 percent (p less than 0.01). These changes were associated with a reduction in tissue lipoprotein lipase activity after propranolol therapy (2.4 +/- 0.3 percent) and an increase after prazosin therapy (2.5 +/- 1 percent, p less than 0.05). These data suggest that treatment with propranolol may be associated with unfavorable changes in the lipid profile that are not observed after treatment with prazosin.

Blood Pressure↗
PubMed1986

Exercise training reduces coronary risk and effectively rehabilitates hemodialysis patients.

This study examines the effects of 12 months of endurance exercise training (cycling, walking and jogging) on lipid profiles, glucose metabolism, blood pressure, anemia and psychological function in 14 hemodialysis patients. Maximal aerobic capacity (VO2max) increased 18% in the exercisers (p less than 0.01), but did not change in 11 controls. This was associated with a reduction in depression, a decrease in dosages of antihypertensive medications, a significant increase in hematocrit and hemoglobin levels (red cell mass rose, plasma volume did not change), a decrease in plasma triglyceride by 23% (p less than 0.05) and an increase in high-density lipoprotein cholesterol (HDL-C) levels by 21% (p less than 0.01) (both HDL-C and triglyceride levels worsened in the sedentary controls), and an 18% increase in glucose disappearance rates (p less than 0.05) in spite of a 52% decrease in fasting insulin levels (p less than 0.01), suggesting that insulin sensitivity improved. These results demonstrate that some of the complications present in hemodialysis patients may be caused by their sedentary life-style, rather than endstage renal disease itself. This suggests that rehabilitation through exercise is possible for these patients. By reducing coronary risk factors in hemodialysis patients, exercise training may also decrease their heightened morbidity and mortality from atherosclerotic complications. These possibilities need to be examined in a longitudinal study.

Adult↗
PubMed1986

Does strict phosphorus control precipitate renal osteomalacia?

Hyperphosphatemia leads to the development of osteitis fibrosa in patients with chronic renal failure. In contrast, crippling osteomalacia may appear in uremic patients who are hypophosphatemic or aluminum intoxicated or who undergo total or subtotal parathyroidectomy. Thus, strict phosphorus control by use of aluminum-containing gels may ameliorate renal osteitis fibrosa, but may potentiate the development of osteomalacia. To evaluate this possibility, we compared the bone histologies of 10 chronic renal hemodialysis patients who consistently maintained predialysis phosphorus levels between 4-5 mg/dl (Strict-P) to those of 46 randomly selected dialysis patients (Random-P). We found that the Strict-P group had lower circulating immunoreactive PTH (P less than 0.02) and alkaline phosphatase (P less than 0.05) levels and, as expected, less evidence of hyperparathyroid bone disease. On the other hand, the Strict-P patients had osteomalacia, as evidenced by moderate osteoid accumulation and reduced capacity of bone to assume a fluorescent tetracycline label. Furthermore, all Strict-P patients had histological evidence of bone aluminum accumulation. We conclude that maintenance of normal serum P levels with aluminum-containing gels in hemodialysis patients prevents severe hyperparathyroid bone disease. Such treatment, however, is also attended by a moderate degree of aluminum-associated osteomalacia.

Adult↗
PubMed1985

Abnormal cell-interactive properties of low-density lipoproteins isolated from patients with chronic renal failure.

Patients with renal failure on maintenance hemodialysis have accelerated rate of atherosclerosis. This, and the fact that chemically modified low-density lipoproteins (LDL) have a better capacity than native LDL to stimulate cholesteryl ester accumulation within macrophages in the vessel wall, led us to examine the possibility that some alteration in apo-LDL may take place in chronically uremic patients. We isolated LDL (d = 1.019 - 1.063 g/mL) from 18 patients with chronic renal failure and from 13 normolipidemic controls and compared the interactive properties of the different LDL preparations with cultured fibroblasts. Our results show that "uremic" LDL associates less, is degraded less, and has diminished ability to stimulate cholesteryl ester formation in fibroblasts when compared to normal LDL. LDL carbamylated in vitro showed interactive properties with fibroblasts similar to those of uremic LDL. Uremic LDL was not taken up by scavenger receptors present on rat peritoneal macrophages, similarly to normal LDL. However, the decrease in uptake by fibroblasts of uremic LDL may increase the residence time of these particles within the subendothelial region of the vessel wall, ultimately resulting in increased atherogenicity. Carbamylation of lysine residues of apoB in vivo, abnormal catabolism of LDL due to the absence of functional renal tissue, or triglyceride enrichment of LDL are among the possible explanations for the abnormal properties of uremic LDL.

Adult↗
PubMed1985

Endurance exercise training. An effective therapeutic modality for hemodialysis patients.

These results demonstrate that some of the metabolic complications of chronic uremia treated with maintenance hemodialysis are related to the deterioration in physical fitness and strength that accompanies this chronic disease. Exercise training increased the physical work capacity, improved the lipid profile, normalized insulin sensitivity and glucose metabolism, and lowered the dose of antihypertensive medications required by some of the patients. These changes occurred in the absence of significant changes in diet or body weight. Furthermore, during an equivalent period of follow-up there was a significant deterioration in the lipid profiles of sedentary controls. Thus, exercise training has the potential to reduce the prevalence of many of the medical conditions thought to promote atherogenesis in hemodialysis patients. In addition, there was a significant improvement in the degree of anemia of the exercising patients. None of these metabolic and physiological changes could be attributed to factors related to changes in dialysis scheduling or technology, medications, or diets. Exercise training was associated with an improvement in the mood, level of depression, and psychosocial functioning of these patients; the sedentary controls either became more depressed or reduced their participation in pleasant, socially oriented activities. This raises the possibility that exercise training may have the potential to return some dialysis patients to a more normal social lifestyle, perhaps improving their socioeconomic status and reducing their dependency. These are extremely optimistic possibilities that could have far-reaching implications for the hemodialysis population. The dramatic improvements in lipid and glucose metabolism, hematologic function, blood pressure and work capacity in the exercising patients indicates that aerobic physical training is an effective therapeutic modality with a wide spectrum of effects on many pathologic processes previously thought to be a consequence of chronic uremia. Not only were there major biochemical changes as a result of exercise training, but the psychosocial functioning of these dialysis patients improved. Some of the physiologic changes, such as the increase in work capacity, greater strength and energy, and the rise in hematocrit, contributed to the psychological improvements, but in some patients accomplishing the goal itself (for most a 1-mile jog was the ultimate) seemed sufficient. There are a multitude of potential long-term benefits of exercise training programs for hemodialysis patients.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1985

Muscle protein turnover: effects of exercise training and renal insufficiency.

Chronic renal failure is associated with an enhanced catabolism of muscle protein. To determine the effect of exercise training and moderate renal insufficiency on net protein catabolism and protein synthesis in isolated epitrochlearis muscles, three-fourth nephrectomized and control rats were exercise trained or remained sedentary. Net muscle protein degradation was determined by measuring the rates of release of phenylalanine and tyrosine. Protein synthesis was determined by measuring the incorporation of [U-14C]phenylalanine into muscle protein. Exercise training reduced the elevated protein degradation of uremia to control levels. In control rats, exercise training had no effect on protein degradation. Exercise training increased alanine release in control rats but did not further increase the elevated alanine release of uremia. Protein synthesis was unaffected by both uremia and exercise training. Exercise training in control and uremic rats moderately increased the responsiveness of muscle to insulin by reducing net protein degradation but did not further enhance the insulin-stimulated increase in protein synthesis. Thus exercise training ameliorates the enhanced muscle protein degradation of moderate renal insufficiency.

Alanine↗
PubMed1985

Upper gastrointestinal bleeding in patients with chronic renal failure.

Endoscopy to evaluate upper gastrointestinal bleeding was done for 482 patients over a 42-month period. Fifty-nine patients (12%) had chronic renal failure and upper gastrointestinal bleeding; the remaining 423 did not have renal failure. Angiodysplasia of the stomach or duodenum was the most frequent source of bleeding in patients with renal failure. Angiodysplasia (p less than 0.001) and erosive esophagitis (p less than 0.01) were significantly commoner causes of bleeding in the renal failure population than in the group without renal failure. Recurrent bleeding was also more frequent in patients with renal failure (25%) than in the other patients (11%). Angiodysplasia was the most frequent source of recurrent bleeding in patients with renal failure (53%) whereas peptic lesions were the most likely sources in those without renal failure (51%). These data show that the differential diagnoses of first and subsequent upper gastrointestinal bleeding sites differ for patients with and without chronic renal failure.

Adult↗
PubMed1984

Effects of prazosin and propranolol on blood pressure and plasma lipids in patients undergoing chronic hemodialysis.

Twenty patients receiving hemodialysis who had mild to moderate hypertension were treated with prazosin or propranolol to control predialysis hypertension. Effective blood pressure control was achieved with prazosin (mean dose 8.3 +/- 2.2 mg [+/- standard error of the mean], n = 10) and propranolol (mean dose 123 +/- 39 mg, n = 10). Therapy with prazosin did not significantly affect total plasma triglyceride or total cholesterol levels. The level of high-density lipoprotein (HDL) cholesterol tended to increase, but not significantly. However, the HDL3 subfraction did increase significantly, from 16.3 +/- 1.5 to 20.6 +/- 1.5 mg/dl (p = 0.05). Propranolol therapy increased plasma triglyceride levels, primarily of the very low density lipoprotein class. HDL cholesterol levels decreased from 44.2 +/- 6.7 to 34.7 +/- 4.2 mg/dl (p less than 0.03). The reduction in the HDL cholesterol levels was attributable to a decrease in HDL2 cholesterol levels (from 21.3 +/- 3.8 to 16.3 +/-3.0 mg/dl, p less than 0.04) and HDL3 cholesterol levels (from 23.0 +/- 3.1 to 19.5 +/- 2.1 mg/dl, difference not significant). Thus, both prazosin and propranolol are effective in controlling hypertension in patients undergoing hemodialysis. HDL3 cholesterol levels increased in patients treated with prazosin, but no other significant changes in the plasma lipids occurred. Patients treated with propranolol had a significant decrease in plasma HDL2 and HDL3 cholesterol levels.

Adult↗
PubMed1983

Racial differences in plasma high-density lipoproteins in patients receiving hemodialysis. A possible mechanism for accelerated atherosclerosis in white men.

Among 346 nondiabetic patients receiving long-term hemodialysis, cardiovascular mortality was higher in white than in black men (P less than 0.02) but was similar between black and white women, despite the higher incidence of nephrosclerosis in black men and women (59 and 58 per cent vs. 8 and 10 per cent, respectively; P less than 0.0001). There were significant racial differences in plasma lipid and apoprotein levels in a subset of 100 of these patients. The white men had higher levels of plasma triglyceride and lower levels of high-density-lipoprotein (HDL) cholesterol, apoprotein A-I, and apoprotein A-II than black men; concentrations of HDL, apoprotein A-I, and apoprotein A-II were also lower in white than in black women. The distribution of the HDL subfractions HDL2, HDL3, and HDL3D, as determined by zonal ultracentrifugation, was normal in black and abnormal in white men receiving hemodialysis. HDL2 concentrations were higher in black than in white men by both zonal analysis (P less than 0.05) and polyanionic precipitation of the HDL subfractions (P less than 0.01). The distributions and concentrations of HDL2 and HDL3L were similar in black and white women. Thus, there are marked racial differences in HDL in male patients receiving hemodialysis. The abnormalities in HDL and the hypertriglyceridemia in the white men may explain their high rate of cardiovascular mortality.

Adult↗
PubMed1983

Nodular duodenitis. Pathologic and clinical characteristics in patients with end-stage renal disease.

This prospective study evaluated the radiographic, endoscopic, histologic, and clinical characteristics of nodular duodenitis found in 17 of 50 (34%) patients with end-stage renal disease. By comparison, nodular duodenitis was noted in only 23 of 557 (4%) consecutive endoscopies in a general medical population. Endoscopic nodular duodenitis consisted of two or more nodules, 2.5-7.0 mm in diameter, with apical erythema, with or without tip erosions. Eight patients had nodules in the bulb only, eight had diffuse duodenal nodules, and a single patient had nodules only in the second portion of the duodenum. Single-contrast barium x-rays were sensitive in detecting the nodules only when they were 5 mm or greater in diameter. Some degree of inflammatory infiltrate was found in 14 of 17 (82%) of the patients with nodular duodenitis; 10 of 17 had a moderate to severe histologic grade compared to 3 of 18 (P = 0.015) patients with a normal endoscopic appearance to the duodenum. Several patients with endoscopic nodular duodenitis, in whom biopsies were taken both of the nodule and surrounding mucosa, were found to have a focal histologic lesion which consisted of villous blunting and thickening due to fibrosis and a chronic inflammatory infiltrate or lymphoid aggregate in the stroma. A higher incidence of peptic ulcers occurred in the nodular duodenitis group (3 of 17) compared to the remainder of the group (0 of 33) during a mean follow-up of 38 months (P = 0.03). Resolution of the nodules occurred in six patients following successful renal transplant (four patients) and following vagotomy and pyloroplasty (two patients).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1983

Effects of vitamin D metabolites on protein catabolism of muscle from uremic rats.

Epitrochlearis muscles obtained from normal male Sprague-Dawley rats used as controls (C) and rats with reduced renal mass (Nx) were incubated for 1 hr in Krebs-Ringer buffer containing 5 mM glucose with or without insulin, 25-hydroxycholecalciferol [25(OH)D3] or 1,25 dihydroxycholecalciferol [1,25(OH)2D3]. Plasma levels of 25(OH)D3 were unaffected by reduction in renal mass. Alanine (ALA), tyrosine (TYR), and phenylalanine (PHE) release rates from muscles of Nx rats were increased 40% above C values. Addition of 100 ng/ml of 25(OH)D3 to the incubating media reduced these release rates to C values within 1 hr of incubation. No additive effects with insulin were seen. Addition of 1 ng/ml of 1,25(OH)2D3 did not affect these results. Reduction of renal mass or the addition of insulin or 25(OH)D3 did not affect tissue concentrations of ATP or phosphocreatine. On the other hand, tissue levels of TYR and PHE were increased significantly (approximately equal to 20 to 25%) in muscles from Nx rats compared to C values and were reduced to control values by the addition of 25(OH)D3. The addition of insulin to the incubating media reduced the tissue levels of TYR and PHE in muscles of C rats by approximately equal to 20%, but reduced these levels in muscles of Nx rats by approximately equal to 55%. 25(OH)D3 did not affect tissue levels of cyclic AMP in muscles from either C or Nx rats. Protein synthetic rates were reduced significantly in muscles from Nx rats and returned to C values after 3 hr of incubation but were unaffected by 25(OH)D3. Muscle uptake of 3H,25(OH)D3 was reduced by approximately equal to 30% in muscles from Nx rats compared to C rats. These data suggest that increased muscle protein catabolism exists in rats with reduced renal mass which can be reduced to C values by 25(OH)D3 and does not appear to be mediated through stimulation of adenylate cyclase. 25(OH)D3 did not affect muscle protein synthetic rates. Reduced uptake of 3H,25(OH)D3 by muscles of Nx rats suggests that resistance to this vitamin metabolite may exist at the level of muscle in uremia.

Alanine↗
PubMed1983

Psychological effects of exercise training in hemodialysis patients.

To assess the psychological effects of exercise training in hemodialysis patients 4 dialysis patients, matched by age, sex, and medical history with 4 controls, received psychological testing before and after a 6-month period of exercise training. The trained patients had a 28% improvement in graded exercise treadmill stress test duration and a 13% improvement in aerobic capacity. This was associated with a significant reduction in anxiety and depression (p less than 0.06), but no measurable change in these moods occurred in the control groups. These results suggest that exercise training may improve psychological functioning in dialysis patients.

Adult↗