PubMed Health⌕ Search

Biomedical subjects

H L Moore

Publications and source records attributed to H L Moore.

At least 19 recordsLinked to original sources
PubMed1995

Expected white blood cell counts and differentials in a rat model of peritoneal dialysis.

OBJECTIVE: The purpose of this study was to establish baseline dialysate white blood cell (WBC) counts and differentials in noninfected rats on peritoneal dialysis (PD). DESIGN: Sixteen male Sprague-Dawley rats underwent PD in the first protocol, and eight from the 16 continued PD in the second through fourth protocols. At the beginning of the experiments, all animals had a PD catheter implanted and were initiated on PD with 1.5% dextrose dialysis solution twice daily. In the first protocol, WBC counts and differentials were assessed from day 4 to day 15 of dialysis in noninfected animals to establish "normal values" for such a rat model. In protocol 2, WBC counts and solute concentrations in small aliquots of dialysate obtained from the catheter were compared to values in well-mixed total drainage. Protocol 3 was designed to assess effects of dwell time on WBC counts. Protocol 4 examined the effect of glucose concentration of dialysis solution on WBC counts. RESULTS: In the first protocol, the mean dialysate WBC counts were significantly higher on the fourth day of dialysis, but stabilized below 2500 cells/mm3 by the eighth day. The percentage of neutrophils was stable around 20%-25%. In the second protocol, we found aliquots < 1 mL might underestimate the dialysate WBC count compared to the complete drainage. In the third protocol, WBC counts increased as cycle time became longer, but the percentage of neutrophils remained below 50%. In the fourth protocol, we did not find any effects of glucose concentration of instilled solutions on WBC counts and differentials. CONCLUSION: This study of WBC counts and differentials in noninfected rats on peritoneal dialysis establishes the range above which infection should be suspected. WBC counts increase with cycle time. Small dialysate aliquots may underestimate WBC counts. Glucose concentration does not effect WBC counts.

Animals↗
PubMed1995

Predicted and measured daily creatinine production in CAPD: identifying noncompliance.

OBJECTIVE: To evaluate the ratio of measured creatinine (Cr) production to predicted creatinine production as an index of noncompliance in patients on continuous ambulatory peritoneal dialysis (CAPD). DESIGN: A cross-sectional analysis. PATIENTS: One hundred and twenty-one patients on CAPD. MEASUREMENTS: We have calculated Cr production from measured Cr outputs in 24-hour collections of urine and dialysate. Predicted Cr productions were calculated from standard tables. Weekly KT/V urea and weekly Cr clearances were determined from the same 24-hour urine and dialysate collections. Lean body mass (LBM) was calculated from the Cr production. Serum albumin concentration was measured. RESULTS: The ratio of measured/predicted Cr production correlated positively and significantly with weekly KT/V urea, the protein equivalent of nitrogen appearance (PNA), weekly Cr clearance, and LBM. There was a decline in serum albumin concentration at ratios greater than 1.24, supporting the opinions of previous authors who have suggested that ratios greater than 1.24 are highly suggestive of noncompliance with the dialysis prescription. Defining noncompliance as a ratio greater than 1.24 implied that at least 5% of the female and 17% of the male patients were noncompliant. CONCLUSIONS: Declining serum albumin concentrations at higher ratios of measured/predicted Cr production support the opinion that this is an index of noncompliance. However, not all noncompliant patients necessarily have a ratio greater than 1.24. Weekly KT/V urea, weekly Ccr and LBM are all artifactually increased by "washout effects" if all exchanges are done only or mainly on the collection day.

Body Mass Index↗
PubMed1994

Comparison of different measurements of lean body mass in normal individuals and in chronic peritoneal dialysis patients.

To evaluate different methods of measuring lean body mass (LBM) in chronic peritoneal dialysis (CPD) patients, we first made comparisons in seven normal subjects. Seven methods (total body potassium [TBK] counting, bioelectrical impedance with calculations according to Segal and Deurenberg, near-infrared interactance with and without exercise level included as a variable, anthropometric measurements, and creatinine kinetics) were compared with the standard method of underwater weighing (UW) for measuring LBM. Significant correlations with LBM measured by UW (r > 0.938) were found with LBM measured by all other methods. Compared with UW, the best result in normals was found with TBK as it had high r values, small y-intercepts, and slopes of regression lines close to unity in both measurements of LBM and %LBM; in addition, fat-free mass index by TBK best approximated that by UW and TBK had the lowest mean prediction error with UW. In 11 patients on CPD, LBM was measured by all the above methods except UW. Significant correlations of all methods with LBM measured by TBK used as the reference standard were noted (all r > 0.76) in the CPD population. The LBM measured by creatinine kinetics correlated best (by kilograms or percentage of body weight [%BW]) with LBM from TBK compared with the other methods in which values tended to be higher. The fat-free mass index by creatinine output was nearest to the fat-free mass index by TBK. The root mean square prediction error was lowest between LBM by creatinine output and that by TBK. The findings support the concept of measuring creatinine outputs in CPD patients for estimates of LBM as an index of nutritional status as well as for creatinine clearances as an index of adequacy. Total body potassium and creatinine output measurements of LBM reflect the LBM at normal body fluid volumes ("dry weight") and may be better indices of nutrition in dialysis patients than the other techniques, which include excess fluid in the LBM.

Adult↗
PubMed1994

Changes in the peritoneal equilibration test in selected chronic peritoneal dialysis patients.

Fifty-five patients on chronic peritoneal dialysis with two or more peritoneal equilibration tests (PET) performed between 1983 and 1992 with a mean interval of 21.9 +/- 22.7 months were studied retrospectively. Repeated PET were performed when transport changes were suspected rather than routinely. According to the initial PET, there were 16 high (HI), 17 high-average (HA), 15 low-average (LA), and 7 low (LO) transporters. There was a significant decrease in the mean creatinine dialysate to plasma ratio (D/P creatinine) in the HI transporters and an increase in the LA and LO transporters. The mean dialysate to instilled glucose ratio (D/Do) significantly increased in the HI transporters. The change in both the D/P creatinine and the D/Do of an individual strongly and inversely correlated to their respective initial values. The change in D/P creatinine and D/Do were significantly and inversely correlated to each other, indicating an actual transport change. No correlation was found between the change in transport with peritonitis episodes or frequencies. The centripetal [corrected] change of transport toward average described here may explain why low clearances or low ultrafiltration rates due to rapid transport are infrequent causes of peritoneal dialysis technique failure, and why patients who have been dialyzed for a long period are usually HA transporters.

Biological Transport, Active↗
PubMed1994

Lean body mass estimation by creatinine kinetics.

A new technique for estimating lean body mass (LBM) from creatinine kinetics has been developed. It is based on the principle that creatinine production is proportional to LBM and that, in the steady state, creatinine production is equal to the sum of creatinine excretion (urinary and dialytic) and metabolic degradation. This technique was applied to 17 normal subjects, 26 stable, chronic hemodialysis (HD) patients, and 71 stable, chronic peritoneal dialysis (PD) patients. In the HD group, LBM was also determined by bioimpedance in 11 patients and calculated from total body water, measured as the volume of urea distribution of a sterile urea infusion, in 15 patients. In normal subjects and in the PD group, LBM was assessed by creatinine kinetics as well as by bioimpedance, near infrared, and anthropometric techniques. In the HD patients, LBM by creatinine kinetics correlated significantly with LBM from total body water and the bioimpedance technique. There was no statistical difference between the total body water and creatinine kinetics techniques, but the bioimpedance values were systematically higher than those obtained by the kinetic technique. In the PD group and in normal volunteers, LBM values by creatinine kinetics correlated significantly with the other methods but were lower. Forty-seven percent of the HD patients and 66% of the PD patients had significantly lower LBM by creatinine kinetics than expected for their sex and age. Estimation of LBM by creatinine kinetics is proposed as a simple and convenient technique for the routine nutritional assessment of dialysis patients.

Anthropometry↗
PubMed1994

Lithium carbonate decreases ultrafiltration rates in an experimental model of PD.

Animal studies have shown increased fluid absorption from the peritoneal cavity following intraperitoneal (ip) vasopressin. Lithium is known to antagonize vasopressin effects on fluid absorption in kidney distal nephrons. The aim of the present study was to see whether lithium-containing exchanges increase the ultrafiltration rates (UF) during peritoneal dialysis (PD) in rats. PD was carried out in 6 Sprague-Dawley rats with 1.5% dextrose-containing PD solution using 15-ml volumes. Each exchange (ex) took 1 min for inflow, 4 mins for outflow and 25 mins for dwell. All rats underwent 9 consecutive half-hourly exs. During exs 4-6 lithium carbonate 2.5 mM was added to the PD solution. During lithium-containing exs significant increases in the glucose absorption rates (3.9 +/- 7.8 vs 37.5 +/- 8.1 mg/ex; p = 0.025) were associated with significant reductions in the UF (3.03 +/- 0.25 vs 1.78 +/- 0.12 ml/ex; p = 0.005). In conclusion, the isolated increase in glucose absorption without increases in the dialysate protein concentration with ip lithium, may suggest either a selective increase in size of the pores with a mean dimater near that of the glucose molecule or enhanced lymphatic absorption. ip lithium did not increase the UF in a rat model of PD.

Animals↗
PubMed1994

Reproducibility of peritoneal equilibration test (PET) in rats.

The aim of the study was to investigate the reproducibility of the peritoneal equilibration test (PET) for evaluating changes in peritoneal function in a rat model of peritoneal dialysis. A PET with 4.25% Dianeal was performed twice within 48 hours under similar conditions after a catheter insertion (n = 10). No significant differences were found between the D/P ratios of PET 1 and PET 2 for urea nitrogen, creatinine, total protein, and D/D0 ratio for glucose. The results for PET 1 and PET 2 showed highly significant correlations. This study indicates, when carried out under similar conditions, that the PET is a highly reproducible test and can be used to evaluate the function of the peritoneum during peritoneal dialysis in rats.

Animals↗
PubMed1994

Absorption of iron from the peritoneal cavity of rats.

The purpose of this study was to determine absorption rate and toxicity of intraperitoneal iron in rats. Twelve (12) male S-D rats were divided into two groups. Group 1 was given 1.5% Dianeal containing 4 mg/L of iron as ferric chloride and group 2 was given standard 1.5% Dianeal. Preblood samples were obtained at the start of the experiment, and 25 mL of the designated dialysis solution was injected into the peritoneal cavity. Six hours after injecting the solution, the dialysate was drained and post-blood samples were obtained. A specimen for histological examination was taken from each rat at the end of the experiment. The iron concentrations of preserum, postserum, dialysis solution with and without added iron, and drained dialysate, were determined. No remarkable changes of serum iron concentration were observed with the six-hour cycle time. Sixty percent of the injected iron was absorbed. No acute toxicity to the peritoneum was observed.

Absorption↗
PubMed1993

Age and indices of adequacy and nutrition in CAPD patients.

We have examined the correlations of age with 95 demographic, clinical, and laboratory parameters in a continuous ambulatory peritoneal dialysis (CAPD) population. Significant inverse correlations were found with lean body mass, dialysate creatinine concentration, serum creatinine concentration, and dialysate creatinine nitrogen output in grams per week; all these findings are compatible with the well-known decrease in muscle mass with aging. Urea nitrogen output in dialysate and urine predicts Kjeldahl nitrogen output in urine and dialysate applying the Randerson equation similarly in older and younger CAPD patients. The relationship of normalized net protein catabolic rate to weekly urea clearance normalized to total body water is similar for older and younger CAPD patients. Older and younger patients have similar values for serum albumin concentration. In conclusion, the findings suggest that comparable weekly creatinine clearances should yield much lower serum creatinine concentrations in older patients. Poor protein intakes in the elderly should not be attributed to age if weekly urea clearances are low. Increases in protein intake in response to increases in urea clearances are similar in older and younger CAPD patients.

Adult↗
PubMed1993

Cross sectional assessment of weekly urea and creatinine clearances and indices of nutrition in continuous ambulatory peritoneal dialysis patients.

OBJECTIVE: To perform a cross sectional analysis in 71 patients on continuous ambulatory peritoneal dialysis (CAPD) to identify significant correlations of weekly small solute clearances and indices of nutritional status with each other and with patient demographics and other commonly monitored clinical and laboratory parameters. DESIGN: This was a retrospective, cross sectional analysis in 71 patients on CAPD from less than 1 to 105 patient-months (average, 20 months). SETTING: An outpatient CAPD program. PATIENTS: All patients on CAPD in our program at the time of the study willing to undergo the clearance and nutritional status measurements. INTERVENTIONS: No interventions other than the monitoring of their status. MAIN OUTCOME MEASURES: Weekly small solute clearances, dietary protein intake, serum albumin, lean body mass, net protein catabolic rate, and urinary and dialysate nitrogen. RESULTS: Weekly Kt/V urea (weekly urea clearance normalized to total body water) of at least 1.7 and weekly total creatinine clearances (liter/week/1.7 m2) of at least 50 are associated with net protein catabolic rates (PCR) greater than 0.9 g/kg of normalized body weight in average CAPD patients. Kt/V urea and net PCR correlate significantly with serum albumin. High transporters identified by the peritoneal equilibration test have greater albumin losses and lower serum albumin concentrations. Estimates of lean body mass correlate significantly with serum albumin and net PCR; lean body mass correlates significantly and inversely with age. CONCLUSIONS: Greater small solute clearances are associated with better nutritional status.

Adult↗
PubMed1992

Peritoneal clearances of carbon dioxide in the rat.

In our previous rat studies (Kidney Int. 1991; 39: 608-617) we evaluated peritoneal clearances (Cp) representing near exclusively diffusive CO2 transfer: for isosmotic (0.37% dextrose) and hyperosmotic (15% dextrose) solutions with pH 7.2-7.3, CpCO2 were 1.20 +/- 0.08 and 1.84 +/- 0.04 ml/min, respectively. In the present studies we have compared Cp of CO2 gas and HCO3- in anesthetized rats (n = 22) using solutions with dextrose contents as mentioned above but with pH 6.5 or 7.6; we have also evaluated how much Cp CO2 measurements obtained with solutions at these pH values differ from Cp shown earlier with the solutions of pH 7.2-7.3. Cp of CO2 gas and HCO3- were significantly higher under hyperosmotic than isosmotic conditions. The use of solutions of pH different from 7.2-7.3 resulted in higher Cp of CO2 gas: with isosmotic solutions of pH 6.5 and 7.6 mean increases were 25 and 75%, respectively; with hyperosmotic solutions respective increases were 45 and 134%. We conclude that dialysis solution osmolality and pH significantly change Cp of CO2 gas and HCO3- in the rat. For evaluation of peritoneal blood flow from diffusive transfer parameters of CO2 gas, smaller overestimation can be expected when dialysis solution pH is slightly under-than overadjusted compared to blood pH.

Animals↗
PubMed1991

Ultrafiltration and effective peritoneal blood flow during peritoneal dialysis in the rat.

The dependence between maximum net ultrafiltration rate (nUFR) created by 15% dextrose dialysis solution and effective peritoneal capillary blood flow (EPBF) estimated by the diffusive mass transport coefficient (KBD) and peritoneal clearance (Cp) of CO2 gas was evaluated during 30 minute, 15 ml peritoneal dialysis exchanges in anesthetized rats (N = 18). The values of KBD for CO2 suggested a mean EPBF of 1.9 +/- 0.1 (SEM) ml/min for isosmotic exchanges and 2.7 +/- 0.2 ml/min for hyperosmotic ones with a mean maximum nUFR of 0.43 +/- 0.01 ml/min. Cp of CO2 measured after the first five minutes of dwell underestimated EPBF. In normally hydrated rats, maximum nUFR was achieved when the peritoneal filtration fraction was 32 +/- 2%. This value is similar to the glomerular filtration fraction in rats of 30%. Thus, our results indicate the following relationships: EPBF = (approximately 3 x maximum nUFR)/(1 - hematocrit). EPBF was about six times greater than maximum nUFR and exceeded about 57 times nUFR obtained under isosmotic conditions. These differences between EPBF and nUFR suggest normal EPBF is not a major limiting factor for maximum ultrafiltration achieved during peritoneal dialysis.

Animals↗
PubMed1991

Morphology of peritoneal dialysis catheter tunnel: macroscopy and light microscopy.

There is scanty knowledge of the morphology of peritoneal dialysis catheter tunnels in humans, even though such knowledge may impact on peritoneal catheter design, implantation and postimplantation care. Past descriptions of catheter tunnels are based mainly on data from animal experiments. Based on these data, it has been assumed that epidermal spreading is inhibited by collagen fibers ingrown into the cuff. Our preliminary investigation indicated that this may not be the case in humans and led us to study catheter tunnel morphology in more detail. Eighteen catheter tunnels (2-5mm of tissue around the catheters) were removed in 17 peritoneal dialysis patients. The catheters were inserted 30 to 2013 days prior to removal (median 366 days). The catheters were removed electively or because of infectious or noninfectious complications. Contrary to the observations in animals, in only 1 case did epithelium extend to the cuff with only a minimal amount of granulation tissue present at the end of a 9 mm long sinus tract. In the remaining cases, the leading edge of the epithelium always met granulation tissue 1-14 mm from the exit, and the cuffs were found 8-33 mm from the exit. In tunnels older than 197 days, dense fibrous tissue was ingrown into the cuffs, and a dense fibrous capsule surrounded the cuff. The uninfected intercuff segment formed a pseudosheath, indistinguishable from a tendon sheath or synovial membrane. Infection in the catheter tunnel propagates through the part of the cuff adjacent to the tubing inside the capsule, suggesting that the cuff per se does not constitute a major barrier for spreading infection. This observation, by exclusion, infers that the beneficial role of an external cuff in decreasing exit infections is by providing firm anchorage of the catheter resulting in restriction of its piston like movement and thereby minimizing trauma and inward conveyance of outer sinus tract flora.

Adolescent↗
PubMed1990

Tidal peritoneal dialysis with racemic or L-lactate solutions.

UNLABELLED: To see if rapid lactate absorption on tidal peritoneal dialysis (TPD) would overwhelm D-lactate metabolism using racemic lactate and/or L-lactate metabolism using all L-lactate, five patients underwent 8-h TPD treatments with racemic lactate solution one day and with L-lactate another. Lactate concentrations (total) were 40 mmole/L, flow rates 27.3 L/8 h, tidal and reservoir volumes each 1.5L, tidal cycles 24-26 min, and net ultrafiltration per tidal cycle 70 to 99 mL. RESULTS: Mean absorptions of D and L-lactate were 24.2 and 25.1%, respectively, compared to glucose at 14.6%. Urea clearances averaged 21.4 mL/min. Mean blood D-lactates at baseline were 0.6 +/- 0.5 SD mmole/L and after 8 h of TPD were 0.6 +/- 0.4 and 0.7 +/- 0.3 using L-lactate and racemic solutions, respectively; similar values for L-lactate were 1.2 +/- 0.3 at baseline and 1.2 +/- 0.3 and 1.2 +/- 0.5 after 8 h with L-lactate and racemic solutions. delta blood pH values were + 0.02 +/- 0.01 and + 0.04 +/- 0.03, while delta bicarbonate values were + 1.7 +/- 0.9 and + 0.7 +/- 1.0 for the all L and racemic studies, respectively. The total mmoles of L-lactate absorbed per 8 h of TPD with all L solution (greater than 300 mmoles) are greater than ever reported for peritoneal dialysis, but did not increase blood lactate levels. It would seem that either type of solution is suitable for TPD. Absorptions and metabolic rates are similar for L-Lactate and D-Lactate.

Adult↗
PubMed1990

Hematocrit and residual renal creatinine clearance in patients undergoing continuous ambulatory peritoneal dialysis (CAPD).

In a recent report, the relationship between renal creatinine clearance and hematocrit in patients with renal creatinine clearances, ranging from 55 to 8 mL per min. per 1.73 square meters of body surface area, was analyzed. The authors of this study have performed a cross-sectional analysis of the relationship of hematocrit to residual renal creatinine clearance in patients on continuous ambulatory peritoneal dialysis (CAPD). The authors of this study wanted to examine whether or not these hematocrits fall within extrapolations of the published 95% confidence limits for males and females with renal failure prior to end-stage renal disease and dialytic intervention. Authors also compared regression intercepts at residual creatinine clearances of 0. Most of the CAPD patients had hematocrits within the upper half or above the extrapolated 95% confidence limits for the predialysis population. Within the CAPD population, there were no significant correlations of hematocrit with residual creatinine clearance at these lower ranges. The degree of scatter in the CAPD population for hematocrit values was similar to that in the predialysis population. Residual creatinine clearance appears to be a crude index of the increasing severity of multiple factors that may contribute to the anemia. CAPD appears to maintain or improve hematocrit as renal mass and function decline.

Anemia↗
PubMed1989

Pentoxifylline does not influence maximum ultrafiltration rates and peritoneal transport in rats.

Previous publications have suggested that peritoneal capillary blood flow and filtration pressure equilibrium may limit ultrafiltration rates with very hypertonic exchanges. Rats were treated with pentoxifylline, which decreases blood viscosity by increasing red blood cell deformability. Decreases in blood viscosity should reduce microcirculatory resistance and increase effective capillary flow. Transport studies were performed after 2, 4, and 8 weeks of therapy with peritoneal dialysis solutions containing 15 grams % dextrose and using 30-min cycles. Even though rats ingested near the maximum recommended dose of pentoxifylline (20 mg/kg) significant changes in blood viscosity and shear stress were not detected compared to controls. Also, there were no significant differences in clearances of urea and phosphorus, glucose absorption, protein losses, and net ultrafiltration compared to controls.

Animals↗
PubMed1987

Maximum ultrafiltration rates during peritoneal dialysis in rats.

It has been suggested that filtration pressure equilibrium could occur in peritoneal capillaries during peritoneal dialysis with very hypertonic exchanges. Rats were exposed to peritoneal dialysis solutions using 16 ml instillations, 30 minute cycles, and dextrose concentrations from 1.4 to 20 g%. There was a plateau in ultrafiltration per exchange at mean osmotic gradients above 360 mOsm/kg H2O near 12.5 ml/ex (0.42 ml/min). The findings are also compatible with filtration pressure equilibrium predictions at an effective capillary plasma flow of 0.84 ml/min and a filtration fraction near 50%. Studies with cardiovascular drugs (norepinephrine i.v., nitroprusside i.p., and dobutamine i.v.) showed no effects on the maximum ultrafiltration rates. This might indicate that flow is rather fixed because of known microcirculatory effects of solutions themselves.

Animals↗