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Biomedical subjects

H R Harter

Publications and source records attributed to H R Harter.

At least 37 records · Page 2Linked to original sources
PubMed1983

Effects of exercise training on muscle protein catabolism in uremia.

The effects of exercise training on muscle protein catabolism in uremia were studied in female rats. Rats made uremic by 3/4 nephrectomy were compared with sham-operated control female rats under conditions of exercise training by swimming or no exercise. The release of amino acids from epitrochlearis muscle in vitro was measured. Body weight epitrochlearis muscle weight, and epitrochlearis protein content were similar among groups. Uremia increased the release of phenylalanine and tyrosine 33% and alanine 50% from muscle of sedentary rats. Citrate synthase activity and glycogen content of muscle were increased twofold by exercise in both controls and uremics. Exercise increased the release of alanine (60%), glutamine (50%), and pyruvate (30%) from muscles of control rats, but it decreased to control levels the release of phenylalanine and tyrosine in uremic rats. Alanine release remained elevated. To determine if exercise training increases in vitro muscle sensitivity to insulin, we incubated muscle with and without 0.01 U/ml of insulin. Phenylalanine and tyrosine release was reduced minimally by insulin in both sedentary uremic and control groups. Glucose uptake was enhanced by 55% in both groups. But in the exercised uremic and control groups, insulin reduced phenylalanine and tyrosine release by 50% and increased glucose uptake by 75%. These results suggest that exercise training reduces muscle protein catabolism in uremia; and this reduction is associated with enhanced muscle response to pharmacologic doses of insulin in control and uremic rats.

Amino Acids↗
PubMed1983

Therapeutic benefits of exercise training for hemodialysis patients.

Twenty-five hemodialysis patients were randomized into comparable exercising (E, N = 14) and sedentary control (N = 11) groups. After baseline testing, training was 3 to 5 times weekly for a mean of 12 +/- 4 (SD) months. Maximal aerobic capacity increased 21% (P less than 0.01), and the durations for the graded exercise stress test improved 19% (P less than 0.01) in E, but did not change in controls (8 +/- 4 months). Declining blood pressures in 8 hypertensive E led to reductions in antihypertensive medications; no changes occurred in 9 hypertensive controls. Exercise lowered plasma total triglyceride levels 33% (280 +/- 258 to 175 +/- 95 mg/dl; P less than 0.01), but no change occurred in total and low-density lipoprotein cholesterol concentrations. High-density lipoprotein cholesterol levels rose 16% in E (31 +/- 9 to 36 +/- 12 mg/dl; P less than 0.02), but did not change in controls. An increase in the affinity of insulin for receptors on mononuclear cells was associated with a 20% decrease in fasting plasma insulin levels (24 +/- 7 to 19 +/- 2 microU/ml, N = 8; P less than 0.05) and a 42% improvement in glucose disappearance rates (1.9 +/- 1.0 to 2.6 +/- 1.2% per min, N = 6) in E. There were no changes in the body weights or diets of the patients. A 27% increase in red blood cell mass (P less than 0.02) with no change in plasma volume resulted in a 27% increase in hematocrit (24 +/- 3% to 31 +/- 5%, P less than 0.01) and a 20% increase in hemoglobin (8 +/- 1 to 10 +/- 2 g/dl; P less than 0.01) in E.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1982

Minerals, vitamin D, and parathyroid hormone in continuous ambulatory peritoneal dialysis.

The effects of continuous ambulatory peritoneal dialysis on parathyroid hormone (PTH) and mineral metabolism were evaluated in ten patients. Utilizing a PTH radioimmunoassay, which measures both intact hormone and carboxyl-terminal PTH fragments, it was found that the mean clearance of immunoreactive parathyroid hormone was 1.5 +/- 0.73 ml/min (SEM) yielding a daily net removal of 13.6 +/- 3.2% of estimated total extracellular parathyroid hormone. Gel electrophoresis of the dialysate revealed the presence of both intact parathyroid hormone and fragments in a similar pattern to that of peripheral plasma. Normal levels of 25-(OH) vitamin D and vitamin D binding protein were observed prior to the initiation of continuous ambulatory peritoneal dialysis and following 6 months of treatment. Timed dialysate collections (N = 93) demonstrated a daily calcium influx of only 9.9 +/- 9.7 mg. The daily removal of phosphorus was 308.4 +/- 15.5 mg. Despite elevated serum magnesium levels in all patients, the net daily removal was inadequate (31.2 +/- 15.5 mg). It was concluded that: (1) Unlike chronic hemodialysis, continuous ambulatory peritoneal dialysis removes significant amounts of parathyroid hormone. (2) Normal 25-(OH) vitamin D and vitamin D binding protein levels are maintained with continuous ambulatory peritoneal dialysis despite large protein losses. (3) Substantial amounts of phosphorus are removed with continuous ambulatory peritoneal dialysis but not to an extent that precludes use of phosphorus binders. (4) Dialysate containing lower magnesium and possibly higher calcium concentrations should be made available to improve mineral homeostasis.

Calcifediol↗
PubMed1982

Acute renal failure. 1. Classification, evaluation, and clinical consequences.

Urinalysis and urine chemistries are most helpful in determining whether acute renal failure is due to a prerenal, renal, or postrenal cause. A plain film of the abdomen should be obtained, with ultrasound or computed tomography also being done if obstruction is suspected. When prerenal and postrenal causes have been excluded, the cause should be considered to be acute tubular necrosis, which progresses through initiating, oliguric (or sometimes nonoliguric), diuretic, and recovery phases. Acute tubular necrosis can produce a variety of clinical consequences affecting the entire body, including hyperkalemia, acidosis, hypocalcemia, anemia, and infection, as well as various cardiovascular, neurologic, and gastrointestinal problems.

Acute Kidney Injury↗
PubMed1982

Acute renal failure. 2. Pathophysiology, prevention, management, and prognosis.

During the past five years, much has been learned about the complex pathophysiology of acute renal failure. A number of mechanisms appear to be involved, including cell swelling, inhibition of prostaglandin synthesis, tubular obstruction, and disruption of the basement membrane of the proximal tubule. For patients at high risk of acute tubular necrosis, prophylaxis with mannitol or furosemide (Lasix) should be considered under certain circumstances. If this syndrome does occur, management should focus on maintenance of proper fluid and electrolyte levels and nutrition, which is facilitated by dialysis. The prognosis of acute tubular necrosis has changed little in the past ten years, and mortality remains high.

Acute Kidney Injury↗
PubMed1982

Peripheral nerve entrapment syndromes in chronic hemodialysis patients.

15 of 271 patients (6%) treated with chronic hemodialysis developed peripheral nerve entrapment syndrome of the median or the ulnar nerve. The majority of these patients were female (p less than 0.03). Fistulas located in arms with nerve entrapment tended to have higher flow rates than fistulas located in arms without nerve entrapment (57%) vs. 4.4%, p less than 0.001). There was no correlation with the renal diagnosis, previous access surgery in the involved arm, the type of vascular access used, the duration of hemodialysis, the adequacy of dialysis, calcium or phosphate homeostasis, plasma parathyroid levels, or thyroid function. Surgical intervention successfully relieved all symptoms. Return of normal renal function dose not reverse this disorder. Peripheral nerve entrapment is a common surgically correctable cause of neuropathy of the upper extremities in hemodialysis patients.

Adolescent↗
PubMed1980

Metabolic effects of exercise training in hemodialysis patients.

The effects of 9 +/- 6 months of exercise training on lipid and carbohydrate metabolism were studied in six hemodialysis patients. Training lowered triglyceride levels 39 +/- 25% (P less than 0.02) and increased plasma high-density lipoprotein cholesterol levels 23 +/- 22% (before, 26 +/- 5 mg/dl; after, 31 +/- 8 mg/dl; P less than 0.05). There was a 23% improvement in glucose tolerance (P less than 0.01) and a 40% reduction in hyperinsulinism (P less than 0.01) with no significant changes in body weight or diet. There was a 25 +/- 8% increase in hematocrits (before, 22 +/- 2%; after, 27 +/- 2%, P less than 0.01) and a 29 +/- 2% rise in hemoglobin concentrations (before, 7.0 +/- 0.8 g/dl; after, 9.0 +/- 0.6 g/dl, P less than 0.04) in five patients. In addition, during training antihypertensive medications could be reduced in three patients with maintenance of normal blood pressure. The improvements in lipid and carbohydrate metabolism diminished when two patients stopped training. These results suggest that physical training can improve some of the metabolic abnormalities observed in hemodialysis patients and could be important as a therapeutic modality.

Adult↗
PubMed1980

The metabolic and psychological effects of exercise training in hemodialysis patients.

The effect of exercise training on metabolic abnormalities and psychological function was assessed in seven hemodialysis patients. Their initial work capacity was low and improved after 8 months of training. Exercise was associated with a reduction in the dose of antihypertensive medications in four patients and a decrease in phosphate binder therapy in three patients. There was also a rise in hematocrit levels (% delta = 34 +/- 20%, P less than 0.03) and the hemoglobin concentration (% delta = 37 +/- 23%, P less than 0.05) of five males. Plasma glucose levels fell (-5 +/- 2%, P less than 0.05, n = 5) and the glucose disappearance rate improved (20 +/- 7%, P less than 0.02), while hyperinsulinism decreased (-36 +/- 20%, P less than 0.02, n = 5) during training. There was no change in body weight or diet. Exercise lowered plasma triglyceride levels (-41 +/- 28%, P less than 0.02, n = 6) and raised the high-density lipoprotein cholesterol concentration (20 +/- 21%, P less than 0.05, n = 6). Psychological testing (n = 4) demonstrated that exercise training was associated with an improvement in depression, hostility, anxiety, social interaction, and outlook for the future. These results suggest that exercise can improve some of metabolic abnormalities and psychological dysfunction which exists in some dialysis patients.

Adult↗
PubMed1979

Prevention of thrombosis in patients on hemodialysis by low-dose aspirin.

Since platelet cyclo-oxygenase is much more sensitive to inactivation by aspirin than is the enzyme in the arterial wall and low doses of aspirin may prevent thrombosis by blocking thromboxane synthesis, we conducted a randomized, double-blind trial of aspirin (160 mg per day) vs. placebo in 44 patients on chronic hemodialysis. The study was continued until there were 24 patients with thrombi and both groups had been under observation for a mean of nearly five months. Thrombi occurred in 18 of 25 (72 per cent) of patients given placebo and 16 of 19 (32 per cent) of those given aspirin (P less than 0.01). The incidence of thrombosis was reduced from 0.46 thrombi per patient month in the placebo group to 0.16 thrombi per patient month in the aspirin group (p less than 0.005). A dose of 160 mg of aspirin per day is an effective, nontoxic antithrombotic regimen in patients on hemodialysis.

Acetylation↗
PubMed1979

Effects of reduced renal mass and dietary protein intake on amino acid release and glucose uptake by rat muscle in vitro.

Epitrochlearis muscles obtained from normal male Holtzman rats used as controls (C) and rats with reduced renal mass (Nx) fed isocaloric diets of varying protein content were incubated in Krebs-Ringer buffer containing 5 mM glucose for 1 or 3 h with or without insulin. Alanine (ALA) release rates from muscles of Nx rats were increased 40% above C values after 1 h of incubation regardless of protein intake. Addition of insulin decreased the ALA release from muscles of Nx rats to C values in animals fed 10 and 20% casein and chow but did not in rats fed 40% casein. After 3 h of incubation, all ALA release rates decreased by congruent with40%. The ALA release from muscles of Nx rats fed 10% casein was comparable to C values and decreased further with the addition of insulin. On the other hand, ALA release from muscles of Nx rats fed 20 and 40% casein as well as chow remained significantly elevated above C values, but responded to the addition of insulin with a reduction in release rates to C values, except from the muscles of Nx animals fed 40% casein. Tyrosine (TYR) and phenylalanine (PHE) release rates also were increased in muscles from Nx rats compared with C after 1 h of incubation. Release rates were highest in the Nx group fed 10% casein and decreased with increasing protein intake. Addition of insulin decreased the release rates of Nx rats to C values in each group. After 3 h of incubation, release rates of TYR and PHE in muscles from Nx rats remained significantly above C values for all groups, but responded to the addition of insulin with a decrease to C values. Glutamine and glutamate release were not significantly affected by reduction in renal mass.Base-line glucose uptake by all groups of muscles from Nx rats was significantly greater than corresponding C values, but maximal insulin-stimulated glucose uptake was comparable in all groups. Tissue pool sizes for glycogen, ATP, phosphocreatine, ALA, glutamate, and glutamine were unaffected by reduction in renal mass. The results indicate that Nx is associated with accelerated ALA, TYR, and PHE release from muscle. ALA release rose with increasing protein intake and decreased to values observed from C muscles after addition of insulin except in Nx animals fed 40% casein. TYR and PHE release decreased with increasing protein intake and also decreased to C values with the addition of insulin. The data also suggest that ALA release is not dependent upon glucose uptake in muscles from either C or Nx rats.

Alanine↗
PubMed1978

Venous angiography and the surgical management of subcutaneous hemodialysis fistulas.

Venous angiography of subcutaneous arteriovenous (A-V)) hemodialysis fistulas involves venous injection of radiographic contrast material which spreads throughout the venous system and into the arteries via the A-V anastomosis when blood flow to the extremity is temporarily occluded. Direct arterial cannulation is avoided. Subsequent restoration of blood flow with rapid sequential roentgenograms differentiates arteries from veins and identifies direction of fistula blood flow. A 44 month experience with 125 consecutive studies in 82 patients was performed with a 0.8% complication rate. Indications for fistulography included insufficient blood flow during dialysis (67%), cardiac failure (10%), aneurysms (6%), sepsis of undertermined site (6%) and other (77%). Roentgenographic findings identified vascular stenoses or occlusions (45%), malpositioned dialysis needles (11%), aneurysms (9%), unsuitable veins for dialysis (6%), absence of septic origin (5%), abnormal flow rates or patterns (5%), technically unsuitable studies (2%) and normal or baseline studies (17%). Information useful in planning clinical management of the patient was obtained in 88% of studies and fistular operations were performed in 65 patients (52%). Venous fistulography can be an effective and safe method of evaluating and planning correction of A-V dialysis fistula complications.

Adolescent↗
PubMed1978

Complications associated with arteriovenous fistulas in patients undergoing chronic hemodialysis.

Over a two-year period, 100 venous angiograms were performed on 75 patients because of difficulty with vascular access. Seventy percent of the patients had decreased arterial flow or increased venous resistance. High output failure, sepsis, and aneurysm formation were also found. Venous angiography of the fistula demonstrated significant stenosis in 40% of the cases as well as total occlusion by thrombus in 9%, aneurysm formation in 7%, and abnormal fistula needle placement or anatomic abnormalities in 20% of the cases. Definitive diagnosis with the aid of venous angiography permitted specific surgical intervention in 62% of the cases, and identified new sites for needle placement in 18% of the cases, thus prolonging fistula life and reducing the need for new fistula placement. Our experience with local cellulitis of the fistula site and sepsis is also discussed.

Adult↗
PubMed1978

Upper gastrointestinal disease in chronic renal failure. A prospective evaluation.

A prospective study was undertaken to determine the incidence of upper gastrointestinal disease in 85 chronic renal failure (CRF) patients on hemodialysis. Upper gastrointestinal x-rays were obtained for 83 patients, and enlarged gastric and duodenal folds were seen in 12% (10/83) and 42% (35/83) of the cases, respectively. Panendoscopy performed on 60 persons revealed gastritis in 22% (13/60), nodular duodenitis in 60% (35/60), and esophagitis in 13% (8/60). No peptic ulcers were identified either radiologically or endoscopically. Pathologic examination of mucosal biopsy specimens demonstrated gastritis in 46% (21/46) and duodenitis in 43% (22/51) of patients. A highly significant correlation was found between endoscopic and radiologic duodenitis (P less than .0001) and also between endoscopic and pathologic duodenitis. We have demonstrated a high incidence of mucosal inflammation but not ulcer disease in CRF patients. These lesions may predispose these individuals to gastrointestinal bleeding following renal transplantation.

Adolescent↗