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Biomedical subjects

K D Nolph

Publications and source records attributed to K D Nolph.

At least 199 records · Page 11Linked to original sources
PubMed1978

Evaluation of permeance in peritoneal dialysis.

Evaluation of permeance in peritoneal dialysis. Relations were developed to calculate permeance based on a minimum number of experimental measurements. Permeance is the product of the effective peritoneal area times its mass transfer coefficient. The relations were used on clinical data obtained with and without nitroprusside, a direct vasodilator, added to the dialysate. Nitroprusside increased permeance 34% for BUN and about 100% for creatinine and inulin. The equivalent increase in clearance in a 50 minute exchange protocol would be 24, 60, and 83%. Normalized consecutive concentration data obtained every ten minutes in several long exchanges agree well with calculated values supporting the adequacy of the approach. An expression is also given to calculate the residual dialysate volume left from the previous dialysate exchange. The values calculated ranged from 200 to 500 ml.

Mathematics↗
PubMed1978

Peritoneal dialysis for psoriasis. An uncontrolled study.

Remissions of long-standing psoriasis have been reported in patients starting either chronic hemodialysis or peritoneal dialysis for renal failure. To see if dialysis influences the course of psoriasis in the absence of renal failure, we selected three patients with severe, refractory, long-standing psoriasis to undergo weekly peritoneal dialysis treatments. Two began to improve after the first dialysis, with nearly complete resolution after four and nine treatments, respectively. The third patient showed no objective changes after four dialyses. These findings add to increasing anecdotal reports of psoriasis improving with dialysis and extend the observations to patients without renal disease.

Adult↗
PubMed1978

Continuous ambulatory peritoneal dialysis.

The technique of continuous ambulatory peritoneal dialysis was evaluated in nine patients during 136 patient weeks. The major objectives were to see if continuous ambulatory peritoneal dialysis would provide [1] acceptable control of serum chemistries by usual criteria, [2] adequate removal of sodium and water, [3] tolerable protein losses, and [4] a low prevalence of peritonitis with episodes responsive to therapy with continuing continuous ambulatory peritoneal dialysis. Preliminary findings suggest continuous ambulatory peritoneal dialysis represents an effective ambulatory, portable, internal dialysis technique. Larger-solute clearances per week may approach values six times greater than with most hemodialysis techniques. Small-solute clearances approach dialysate flow rate (8.3 ml/min) and are comparable to other dialysis techniques on a weekly basis. Edema is readily controlled and protein losses should be tolerable with adequate protein intake. Peritonitus occurs on the average every 10 weeks but responds to therapy promptly with continuing continuous ambulatory peritoneal dialysis. If the prevalence of peritonitis can be reduced, continuous ambulatory peritoneal dialysis appears to represent a very attractive dialysis technique.

Adult↗
PubMed1978

Antibodies to nuclear antigens in patients with renal failure.

Nuclear material, presumably from damaged leukocytes, adheres to hemodialysis membranes. Previous studies have shown an increased prevalence of antibodies to nuclear antigens in chronic dialysis patients. Present studies verify the increased prevalence of antibodies to nuclear antigens in 52 of 243 chronic dialysis patients (21.4%). Because antibodies are present only intermittently, prevalence increases with repetitive blood sampling. In patients tested every 3 months over several years on chronic dialysis, the prevalence of antinuclear antibodies approaches 100%. The present studies also demonstrate, however, that the prevalence of antibodies is increased in patients with renal failure who have never undergone hemodialysis (10 of 86, 11.6%). Thus the tendency to form antibodies to nuclear antigens may be associated with renal failure rather than dialysis per se. Higher prevalences with increased time on dialysis and transplantation failure may accordingly reflect the greater duration of renal failure. The prevalence of antibodies to nuclear antigens was not significantly influenced by age, sex, type of kidney disease, major blood group, HLA tissue type, or coil reuse. Significantly lower hematocrits and white blood counts were noted when antibodies were present.

Adult↗
PubMed1978

Effects of ultrafiltration on solute clearances in cuprophan and cellulose hollow fiber dialyzers: in vitro and clinical studies.

Hollow fiber dialyzers are currently available with either regenerated cellulose or thinner walled cuprophan fibers. In vitro and clinical studies were undertaken to compare a cellulose with a cuprophan dialyzer in regard to (1) UF's, (2) small and large solute clearances at high and low TMP's, (3) SC's, and (4) effects of ultrafiltration on diffusive and convective components of clearances. The results show that per square meter of surface area, the cuprophan dialyzer has higher rates of UF per TMP and greater clearances, particularly of larger solutes; also with cuprophan the SC for vitamin B12 is higher. Thus all findings suggest greater permeability of cuprophan fibers. In both dialyzers, total clearances increased with UF by amounts compatible with predicted increases in convective transport; diffusive transport remained stable as TMP was increased.

Cellulose↗
PubMed1978

Comparison of polymer, glucose, and hydrostatic pressure induced ultrafiltration in a hollow fiber dialyzer: effects on convective solute transport.

Ultrafiltration induced by (1) poly(sodium acrylate), (2) glucose, and (3) hydrostatic pressure was studied in a hollow fiber dialyzer. Poly(sodium acrylate) added to dialysate induced large amounts of ultrafiltration without crossing the dialyzer membrane. Sodium ions of the acrylate polymer were osmotically active but were held in dialysate by the impermeant anionic polymer. The hydrostatic pressure equivalent of osmotic pressure induced primarily by the sodium ions approximated that predicted for a completely impermeant molecule. The apparent (net) sieving coefficients for vitamin B12 observed during polymer and hydrostatic ultrafiltration studies were both significantly higher than that observed during glucose ultrafiltration but did not differ from each other. These studies suggest that sodium salts of polyanions can provide an osmotic driving force to yield large amounts of ultrafiltration in dialysis systems and yet not cross the membrane. The studies also suggest that relatively less efficient convective transport with glucose as compared to hydrostatic pressure is neither a membrane phenomenon nor a characteristic of all osmotic pressure induced ultrafiltration. Relatively low effective solute sieving appears to be associated with osmotic induced ultrafiltration with a permeant solute. Under such conditions it is proposed that molecular interaction within the membrane impairs convective transport.

Acrylic Resins↗
PubMed1977

Chemical measurements of inulin concentrations in peritoneal dialysis solution.

Peritoneal inulin clearance during peritoneal dialysis is a useful indicator of efficiency of removal of larger solutes. Peritoneal dialysis solutions usually contain high glucose concentrations that interfere with the chemical measurements of inulin concentration. In these studies, inulin recoveries in simple glucose and peritoneal dialysis solutions with three chemical methods were compared; all methods reportedly were subject to minimal glucose interference. The findings showed one method subject to minimal and predictable glucose interference in all solutions tested. For two methods, interference in peritoneal dialysis solutions exceeded that predicted from glucose alone; this unexpected interference was shown to most likely result from carmalized glucose subsequent to the routine autoclaving of peritoneal dialysis solutions.

Ascitic Fluid↗
PubMed1977

Transerythrocytic concentrations of urea and creatinine in normals and in azotemic patients.

Preliminary studies in our laboratory suggested alterations in the distribution of urea and creatinine between red cells and plasma in azotemic patients, as compared to normal controls. The present studies compare plasma erythrocyte concentrations of urea and creatinine in azotemic patients and in control subjects. Effects of adding exogenous urea and creatinine to the blood of control subjects were also studied. The findings suggest alterations of solute distribution patterns in azotemic blood. Specifically, the proportions of the solutes in cells appear reduced in azotemia.

Creatinine↗
PubMed1977

Short dialysis, middle molecules, and uremia.

The cause of the uremic syndrome remains unknown; the success of dialysis therapy suggests that retained, dialyzable, but unidentified toxic solutes may play a role. Since chronic peritoneal dialysis seems to prevent or improve uremic neuropathy as well as does hemodialysis, it has been suggested that retained solutes of "middle molecular weight" (500 to 5000 daltons) may be major toxins. Only body fluid concentrations of these larger solutes are presumed to be reduced by peritoneal dialysis as well as with hemodialysis, whereas small solute concentrations are relatively poorly controlled. There have been numberous hemodialysis studies to examine the toxic potential of "middle molecules" as compared with that of smaller solutes. Although the importance of "middle molecules" as toxins remains unproved, numberous factors influencing their concentrations in body fluid have been discovered. Studies have also shown a surprising tolerance of patients to many variations in dialysis strategies. Difficulties in defining adequate dialysis have been intensified.

Humans↗
PubMed1977

Effects of ultrafiltration on solute clearances in parallel plate dialyzers.

Clearances of small and large solutes were measured at increasing transmembrane pressure in 3 types of parallel plate dialyzers. Both laboratory and clinical studies were performed. As in previously reported studies in coils, diffusive transport appears to decrease as transmembrane pressure increases. This may reflect blood channel widening, bath channeling, and/or membrane masking by mesh support. For small solutes, decreases in diffusive transport were enough to offset gains by solvent drag and total clearances decreased. In some studies, decreases in small solute clearances with increasing ultrafiltration were large enough to compromise dialysis efficiency.

Diffusion↗
PubMed1977

NaHCO3 and NaCl tolerance in chronic renal failure II.

In patients with chronic renal failure (CRF) (CCr less than 20 ml/min), we have previously demonstrated greater rates of Na excretion (ex) when Na intake was nearly all NaHCO3 as compared to NaCl (both 200 mEq Na daily). Chloride (Cl) wasting on NaHCO3 (with severe Cl restriction) occurred, however, and may in part explain the results. To avoid Cl restriction in 6 patients with CRF (CCr 10-15 ml/min) on an estimated 10 mEq Na and Cl diet, electrolyte ex was compared on NaCl supplements of 200 mEq/day versus a daily mixture of NaHCO3 (100mEq) and NaCl (100 mEq). Periods on NaCl and the mixture lasted 4 days (order randomized) separated by re-equilibration to baseline weight (wt). Mean +/- SEM ex of Na, Cl, HCO3 mEq/day and CCr and deltawt (lbs) are compared below for the 4th day of NaCl vs NaHCO3 intake. (see article). Also there were no significant differences in K excretion, blood pressure, or plasma renin activities. Mean serum HCO3 increased from 21.2 to 25.8 mEq/l (day 1 vs 5, P less than 0.01) reflecting the net positive HCO3 balance on the mixture indicated above. Thus increments of Na intake above a fixed NaCl intake were excreted similarly whether given as NaCl or NaHCO3. Greater Na ex on NaHCO3 may depend on severe Cl restriction and/or higher serum HCO3 levels. If dietary NaCl intakes are near maximum tolerance, NaHCO3 supplementation should be accompanied by reductions in NaCl intake to maintain Na balance,

Adult↗
PubMed1977

Effects of potassium chloride on plasma renin activity during sodium restriction in normal man.

Previous studies have suggested that large intakes of potassium (K) will suppress plasma renin activity (PRA) in normal man. The effect of more modest intakes of K on PRA is unclear. The present study was designed to compare the PRA in 11 normal volunteers maintained on an electrolyte-free diet (7000 J), with and without the addition of 50 mEq/day of potassium chloride (7000 J + KCl), well within the limits of usual dietary consumption. Control recumbent and 2 hr of upright PRA determinations were made by radioimmunoassay prior to the initiation of either the 7000 J diet or the 7000 J + KCl diet and on the fourth day of the diet, at a time when urinary sodium, K, and chloride excretions were near intakes. Mean (+/- S.E.M.) PRA's are indicated in Table II. There are significant (p less than 0.01) differences between (1) all respective recumbent and upright posture positions and (2) before and after the administration of 7000 J and 7000 J + KCl. However, there are no significant differences between (1) control periods or (2) before and after the addition of KCl to the electrolyte-free diet. We conclude from these studies that K, given in modest amounts, has no inhibiting effect on PRA.

Adult↗
PubMed1976

Antibodies to nuclear antigens in patients undergoing long-term hemodialysis.

Free nuclei of damaged leukocytes adhere to hemodialysis membranes. To see if the incidence of antibodies to nuclear antigens is increased in patients receiving hemodialysis, serums from 77 patients undergoing long-term dialysis for one to 66 months were assayed for antibodies to extractable nuclear antigen and native deoxyribonucleic acid (DNA) by hemagglutination technics. Serums from 300 other hospital patients (who did not have diseases known to be associated with antibodies to nuclear antigens) were assayed concurrently. Of the 77 dialysis patients, serums from 19 (25 per cent) were positive for one or both antibodies. Serums from only three (1 per cent) of the 300 other patients had detectable antibodies. The incidence was significantly higher (p less than 0.001) in dialysis patients suggesting the possibility of sensitization to nuclear antigens during hemodialysis.

Adolescent↗
PubMed1976

Uremic autonomic neuropathy: evaluation of ephedrine sulphate therapy for hemodialysis-induced hypotension.

The hemodynamic response to ephedrine sulphate were studied in a patient on maintenance hemodialysis therapy with chronic renal failure due to renal amyloidosis. The evaluation (including cardiac catheterization studies) and estimation of responses to Valsalva maneuvers before and after ephedrine administration documented the diagnosis of autonomic insufficiency. Oral ephedrine failed to influence the episodes of severe dialysis-induced hypotension. Also the patient did not benefit from the infusion of Aramine. These studies suggest that catecholamine stores of adrenergic nerves may be depleted in uremic patients with clinical signs of autonomic neuropathy.

Blood Pressure↗