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Biomedical subjects

H L Moore

Publications and source records attributed to H L Moore.

65 records · Page 4Linked to original sources
PubMedDate not supplied

Leukocyte kinetics in patients with peritonitis on long-term peritoneal dialysis.

Dialysate and blood leukocyte counts were measured during 130 episodes of peritonitis in 91 hospitalized patients on long-term peritoneal dialysis (CPD). The authors found that the blood/dialysate leukocyte count can be less than 1.0, and this is usually the case when dialysate leukocyte count exceeds 20,000/mm3. Dialysate leukocyte removal in a single 2 L drain bag can approach the leukocyte number in the entire circulating blood volume. Daily drainage can remove leukocytes in amounts exceeding the blood leukocyte pool 2 to 3 fold. The observed blood leukocyte counts throughout a range of 2,700 to 10,000 at dialysate leukocyte counts greater than 20,000 per mm3 may reflect: 1) leukocyte removal approaching maximum bone marrow output of leukocytes, and/or 2) increasing microcirculatory margination of leukocytes in those episodes of peritonitis associated with very high dialysate leukocyte counts.

Cells, Cultured↗
PubMedDate not supplied

Continuous ambulatory peritoneal dialysis with a high flux membrane.

The standard peritoneal equilibration test (PET) was performed in 66 patients on CAPD. Patients were classified as low (n = 5), low average (n = 22), high average (n = 27), and high (n = 12) transporters based on the dialysate/plasma creatinine (D/P Cr) after 4 hour dwells. After an average time interval of 14 months on CAPD, indices of dialysis adequacy and nutrition were assessed. Based on monitoring of patient chemistries and drain volumes, peritoneal transport was considered stable during the interval. Instilled volumes and exchange tonicity were individualized in each patient to achieve combined renal and dialysis weekly creatinine clearance and KT/V urea that were not significantly different between groups. Overall, there were significant positive correlations of PET D/P Cr with dialysate albumin concentrations (r = 0.30, p < 0.02) and dialysate albumin losses (g/wk, r = 0.27, p < 0.04). There were significant inverse correlations with lean body mass (r = -0.26, p < 0.03), drain volumes (r = -0.025, p < 0.04), and KT urea by dialysis (L/wk, r = -0.24, p < 0.05). High transporters had significantly (p < 0.05) lower mean serum albumin, net protein catabolic rate (nPCR), lean body mass calculated from creatinine kinetics, and daily creatinine production (and presumably lower muscle mass) compared with one or more lower transport groups. In conclusion, we hypothesize that, in high transporters, use of more hypertonic exchanges with greater glucose absorption may inhibit appetite and nPCR; also, protein losses in drain volumes are increased. High transporters may require increased clearance and protein intake targets compared with other groups to maintain nutrition.(ABSTRACT TRUNCATED AT 250 WORDS)

Biological Transport↗
PubMedDate not supplied

Continuous ambulatory peritoneal dialysis with a high flux membrane. A preliminary report.

The standard peritoneal equilibration test (PET) was performed in 66 patients on continuous ambulatory peritoneal dialysis (CAPD). Patients were classified as low (n = 5), low average (n = 22), high average (n = 27), and high (n = 12) transporters based on the dialysate/plasma creatinine (D/P Cr) after 4 hr dwells. After an average time interval of 14 months on CAPD, indices of dialysis adequacy and nutrition were assessed. Based on monitoring of patient chemistries and drain volumes, peritoneal transport was considered stable during the interval. Instilled volumes and exchange tonicity were individualized in each patient to achieve combined renal and dialysis weekly creatinine clearance and KT/V urea that were not significantly different between groups. High transporters had significantly (p < 0.05) lower mean serum albumin, net protein catabolic rate (nPCR), lean body mass calculated from creatinine kinetics, and daily creatinine production (and presumably lower muscle mass), and higher albumin clearances compared to one or more lower transport groups. In conclusion, we hypothesize that high transporters are prone to protein malnutrition related to increased dialysate protein losses, and perhaps suppression of appetite, with increased use of hypertonic exchanges. High transporters are candidates for protein supplementation on CAPD or transfer to nightly intermittent peritoneal dialysis where short cycles provide more ultrafiltration with less glucose absorption.

Creatinine↗
PubMedDate not supplied

Peritoneal transfer during maximal hyperosmotic ultrafiltration in the rat.

Peritoneal transfer parameters were estimated in rats (n = 24) while maximal net ultrafiltration rate (nUFR) was achieved with 15% dextrose dialysis solution (1,153 mOsm/kg) and compared with those obtained with 0.37% dextrose solution (301 mOsm/kg). Experiments were carried out with dialysis solutions of pH approximately 6.5 and approximately 7.6, respectively, for 15% dextrose dialysis solution and 0.37% dextrose solution. Increases in both convective and diffusive transfer resulted in more than 70% greater peritoneal clearances of urea, potassium, and phosphate with hyperosmotic solutions at both pH values. Protein removal was increased only with a hyperosmotic solution of pH approximately 6.5 compared with isosmotic conditions at the same pH. Results support the hypothesis that increased peritoneal transfer parameters under hyperosmotic conditions depend not only upon enhanced convection but also on factors promoting diffusive transfer.

Animals↗
PubMedDate not supplied

Chronic administration of iron dextran into the peritoneal cavity of rats.

OBJECTIVE: To determine the influence of chronic iron dextran administrations into the peritoneal cavity of rats on function and anatomy of the peritoneal membrane, as well as on erythropoiesis and serum iron. DESIGN: Prospective randomized animal study. SETTING: Animal laboratory. ANIMALS: 36 Sprague-Dawley rats. INTERVENTIONS: The rats were divided into three groups (n = 12). The animals were given standard 1.5% Dianeal (control group) or 1.5% Dianeal containing iron dextran in a concentration of 2 mg/L [low-dose group (LDG)] or 10 mg/L [high-dose group (HDG)]. MAIN OUTCOME MEASURES: On the 8th day, at 3 months, and at 6 months a 2-hour peritoneal equilibration test (PET) and blood tests including hematocrit, serum iron, and total iron-binding capacity (TIBC) were done. After the final PET at 6 months, the peritoneal membrane was evaluated by gross inspection and by light microscopy. RESULTS: Hematocrit and serum iron levels increased only in the HDG and LDG. Peritoneal transport of small solutes decreased significantly in the HDG compared to baseline. All cases of the HDG group revealed peritoneal adhesions and fibrosis around the peritoneal catheter as well as massive iron deposits on the peritoneum. Similar but less pronounced changes were found in the LDG. CONCLUSIONS: These findings suggest an efficient absorption of iron from the peritoneal cavity of rats, however, dialysate iron dextran concentrations of 2 mg/L or greater are toxic to the peritoneal membrane. Therefore, future studies should be performed to determine the minimal effective and nontoxic iron dextran concentrations for intraperitoneal administration.

Animals↗
PubMedDate not supplied

Calculation of 6-hour D/P creatinine ratio from the 4-hour peritoneal equilibration test. The effect of dwell duration on the results.

OBJECTIVES: Since the introduction of the peritoneal equilibration test (PET), the 4-hour dialysate/plasma creatinine (D/P Cr) has been used by several authors for determining continuous ambulatory peritoneal dialysis (CAPD) prescriptions. However, the results have been unsatisfactory because the 4-hr D/P Cr does not accurately reflect the D/P Cr in 24-hr collections. The PET and the 24-hr dialysate collections differ in the duration of dwell and the tonicity and volume of dialysate, all of which influence the equilibrated D/P Cr. It can be assumed that the D/P Cr in 24-hr collections in these patients is closer to a 6-hr D/P Cr. Because a 6-hr PET is inconvenient, we developed a mathematical model to calculate the 5- and 6-hr D/P using the results of a standard PET. DESIGN: In a retrospective analysis, D/P Cr ratios in 24-hr collections and D/P Cr ratios calculated from a mathematical formula were correlated. Using a mathematical model, the data collected fit an exponential relation of the type D/P = a(1-e-t/tau). The values of a and tau are unique for a given patient and were determined using a nonlinear regression technique. The formula performed well on our published data-the true and predicted 6-hr D/P Cr being 0.696 and 0.71, respectively. SETTING: The University Hospital and Clinics, Dalton Cardiovascular Research Center and Dialysis Clinic, Inc., Columbia, Missouri. PATIENTS: All CAPD patients on four 2-L exchanges/day at the time of the 24-hr collections were included. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Closeness of 4-hr and 6-hr D/P Cr values to those of 24-hr ratios. RESULTS: The study group comprised 74 patients (age, mean +/- SEM: 56.4 +/- 1.8 yr) with 80 PETs and 145 (24-hr) collections. The interval between the two tests was 8.3 +/- 0.9 months (0-48.7 months). The median 24-hr D/P Cr of 0.760 did not differ significantly from the predicted median 6-hr D/P Cr of 0.755. A subgroup analysis, based on transport type, showed that this relationship was most precise in the high-average transporters. The predicted 6-hr D/P Cr was within 10% of the 24-hr D/P Cr in 48% of patients and within 20% in 77% of patients. The margin of error was greatest in the low transporters. CONCLUSIONS: To conclude, the 4-hr D/P Cr from a PET cannot be used interchangeably with the D/P Cr in the 24-hr dialysate collections, hence, the clearances calculated thereof will be inaccurate. Using the proposed model, it is feasible to use the 4-hr PET results to obtain 5- and 6-hr D/P Cr values. In our study, using this model, the extrapolated 6-hr D/P Cr is similar to the D/P Cr in 24-hr dialysate collections only in the high-average transporters. Hence, the best way to determine clearances in peritoneal dialysis patients is still by collecting 24-hr dialysates.

Adult↗
PubMedDate not supplied

Effect of dialysis modality and membrane transport characteristics on dialysate protein losses of patients on peritoneal dialysis.

OBJECTIVE: To determine if peritoneal dialysis modality has an impact on protein losses in dialysate. DESIGN: Retrospective, cross-sectional study. PATIENTS: 190 patients who had selected peritoneal dialysis were classified into one of four transport categories (high, high-average, low-average, or low) based on standard peritoneal equilibration test results. Patients were then assigned to continuous ambulatory peritoneal dialysis (CAPD) or nightly intermittent peritoneal dialysis (NIPD) based on membrane transport characteristics and individual preferences. RESULTS: Patients with similar membrane transport characteristics had essentially no differences in dialysate protein and albumin losses whether treated with CAPD or NIPD. CONCLUSIONS: Although high transporters may be better managed with short-dwell therapies such as nocturnal intermittent peritoneal dialysis or daily ambulatory peritoneal dialysis, consistent marked decreases in protein losses cannot be cited as a benefit of NIPD over CAPD.

Biological Transport, Active↗
PubMedDate not supplied

Toward targets for initiation of chronic dialysis.

OBJECTIVES: To better define the targets for initiation of chronic dialysis, we compared the relationship between the normalized protein equivalent of nitrogen appearance (nPNA, g/kg standard weight/day) and weekly urea clearance (Kt) normalized to total body water (V) in predialysis chronic renal failure (CRF) patients and in patients on continuous ambulatory peritoneal dialysis (CAPD) and hemodialysis (HD). We also studied the relationships of other nutritional parameters to weekly Kt/Vurea in CRF patients. DESIGN: This cross-sectional study was a prospective observational design meant to study each patient once. SETTING: The University Hospital and Clinics and Harry S. Truman VA Medical Center, Columbia, Missouri. PATIENTS: Forty-five consecutive predialysis CRF patients were enrolled and the results compared with patients on CAPD and HD. RESULTS: In CRF, the nPNA calculated from urea appearance correlated with the weekly Kt/Vurea (r = 0.57, p < 0.0001) and, using exponential best-fit, nPNA = 1.217 x (1-e-0.769Kt/V). This exponential relationship was similar to that for CAPD and both were different from that in patients on HD. Likewise, nPNAs, calculated from Kjeldahl nitrogen output, and weekly Kt/Vurea were correlated (r = 0.37, p = 0.014) and, using exponential best-fit, nPNA = 1.102(1-e-0.867Kt/V), similar to the relationship in patients on CAPD. Evidence is presented that these relationships are not explained only by mathematical coupling. There was a significant correlation between the weekly Kt/Vurea and 24-hour urinary creatinine excretion. CONCLUSIONS: The findings suggest that in CRF, as in CAPD, a weekly Kt/Vurea less than 2.0 is likely to be associated with a nPNA less than 0.9 g/kg standard weight. In CRF patients, initiation of chronic dialysis should be considered if weekly renal Kt/Vurea falls below 2.0 and a nPNA greater than 0.8 is desired.

Adult↗
PubMedDate not supplied

Evidence that urea is a better surrogate marker of uremic toxicity than creatinine.

The protein equivalent of nitrogen appearance normalized to standard weight was determined from urea nitrogen appearance (nPNA U) and from total Kjeldahl nitrogen appearance (nPNA K) in dialysate and/or urine in 45 predialysis patients (pre D) and in 95 patients on continuous ambulatory peritoneal dialysis (CAPD). Correlations with weekly Kt/Vurea and creatinine clearance (Ccr, L/wk/1.73 m2) were determined; renal contributions of CCr in both populations were calculated both as total CCr (A) and as CCr by GFR (CCr [B], mean of renal CCr and Curea). Correlations with weekly Kt/Vurea were significant in individual (pre D:nPNA U 0.57, p < 0.01, and nPNA K 0.37, p < 0.01; CAPD:nPNA U 0.50, p < 0.01, and nPNA K 0.43, p < 0.01) and pooled populations (nPNA U 0.54, p < 0.01 and nPNA K 0.37, p < 0.01). Correlations with neither Ccr (A) nor Ccr (B) were significant. The data also allowed comment on mathematical coupling. Ccr vs nPNA K correlations share even more mathematical couplers than does the nPNA K vs Kt/Vurea correlation, yet the correlation of nPNA K with Ccr is quite low. The authors conclude that urea is a better surrogate marker of small molecular weight toxins that inhibit protein intake in uremia, and correlations of nPNA with Kt/Vurea represent more than simple mathematical coupling.

Biomarkers↗