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Biomedical subjects

R Gokal

Publications and source records attributed to R Gokal.

At least 91 records · Page 5Linked to original sources
PubMed1993

Can ultrafiltration occur with a hypo-osmolar solution in peritoneal dialysis?: The role for 'colloid' osmosis.

1. In peritoneal dialysis the removal of excess body water (ultrafiltration) is traditionally achieved by means of dialysis solution made hypertonic to plasma by the addition of an osmotic agent. In vitro, the osmotic flow may be directed against the osmolality gradient by using a hypo-osmolar solution, but this phenomenon has not previously been applied to clinical peritoneal dialysis. 2. The ultrafiltration performances of hypo-osmolar dialysis solutions containing a high-molecular-weight glucose polymer (weight average molecular weight 22,000), isolated by fractionation of hydrolysed corn starch, were compared with those of hypertonic glucose solutions over a 12 h exchange in 11 patients well established on continuous ambulatory peritoneal dialysis. 3. Five per cent (272 +/- 1.1 mosmol/kg) and 7.5% (277 +/- 2.0 mosmol/kg) glucose polymer solutions produced net ultrafiltration of 243 +/- 53 and 526 +/- 59 ml that were significantly greater than the ultrafiltration of -48 +/- 96 and 223 +/- 84 ml associated with 1.36% (339 +/- 1.9 mosmol/kg) and 2.27% (393 +/- 3.2 mosmol/kg) glucose solutions, respectively. The net ultrafiltration with 10% glucose polymer (284 +/- 2.0 mosmol/kg) and 3.86% glucose (482 +/- 1.6 mosmol/kg) solutions were similar (699 +/- 48 versus 708 +/- 82 ml). 4. The transperitoneal absorption of glucose polymer was substantially lower than that of glucose solutions as was the potential calorie load per millilitre of ultrafiltrate. 5. The addition of 0.35% glucose (molecular weight 180) to 7.5% glucose polymer solution raised the dialysate osmolality to an iso-osmolar level (299 +/- 0.8 mosmol/kg) and produced ultrafiltration which was 29% greater than with 7.5% glucose polymer solution alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Serum lipoprotein (a) concentrations in patients undergoing continuous ambulatory peritoneal dialysis.

Lipoprotein (a) is a subspecies of low-density lipoprotein which possesses as part of its protein moiety a mutant form of plasminogen termed apolipoprotein (a), and which may be closely related to the risk of ischaemic heart disease and cerebral infarction. We have investigated the serum concentrations of lipoprotein (a) and other lipoproteins in 24 male patients on CAPD and compared them to healthy men (n = 100) and to age-matched healthy controls (n = 38). The most striking finding was a substantial elevation of serum lipoprotein (a) in CAPD patients in whom it was 46.9 (2.2-168) mg/dl (median and range) compared to 9.0 (< 0.6-87.4) mg/dl in healthy control group and 6.7 (< 0.6-84.2) mg/dl in age-matched controls (both P < 0.001). Patients, when compared to healthy men, also had significantly increased serum triglycerides (median and range, 1.94 (0.55-8.00) versus 1.24 (0.36-4.40) mmol/l; P < 0.001), very-low-density lipoprotein cholesterol (median and range, 0.98 (0.10-3.71) versus 0.46 (0.10-1.17) mmol/l; P < 0.001), and lower-high-density lipoprotein cholesterol (mean +/- 1 SD, 1.26 +/- 0.29 versus 1.35 +/- 0.31 mmol/l). Of these, however, only the difference in very-low-density lipoprotein cholesterol remained statistically significant (P < 0.001) in comparison to age-matched controls. The marked elevation of serum lipoprotein (a) in patients on CAPD may be due to increased hepatic synthesis as a consequence of the substantial amounts of plasma proteins lost in the dialysate. Elevated serum lipoprotein (a) concentrations in CAPD patients may contribute to their risk of coronary artery disease.

Adult↗
PubMed1993

Effects of azathioprine on response of renal anaemia to subcutaneous recombinant human erythropoietin.

AIMS: To determine the effect of concomitant azathioprine treatment on the response of patients with renal failure to treatment with subcutaneous recombinant human erythropoietin (r-HuEPO). METHODS: Two groups of patients with renal failure not receiving haemodialysis were studied. One comprised seven patients receiving erythropoietin alone, the second consisted of nine patients who were also treated with azathioprine. The haematological changes were monitored, and the functional erythropoietic response was studied by two different ferrokinetic models. One analysed the initial, the other the extended plasma iron clearance. Studies were performed before r-HuEPO treatment on all 16 patients, and repeated on 11 of these when the target haemoglobin (10-11 g/dl) was achieved and stabilised. Total erythropoiesis was determined using both techniques. Analysis of the extended plasma iron clearance also permitted calculation of both effective and ineffective erythroid activity. RESULTS: The haematological response to r-HuEPO was the same for both patient groups. Measurement of total erythropoiesis by both ferrokinetic methods showed good correlation. For those receiving long term azathioprine, the percentage ineffective erythropoiesis was high compared with that of the other patients, and remained so for as long as they continued with azathioprine. For those uncomplicated by azathioprine treatment, r-HuEPO increased levels of both effective and ineffective erythropoiesis by the same degree. A substantial reduction in ineffective erythropoiesis was shown only by those patients who either discontinued or reduced their azathioprine once they started r-HuEPO treatment. CONCLUSIONS: Azathioprine increases ineffective erythropoiesis. In this study, the r-HuEPO dose was sufficient to overcome this effect and promoted effective erythropoiesis so that the anaemia lessened. Measurement of total erythropoiesis provided limited information on the functional changes involved, differentiation of effective from ineffective erythropoiesis being necessary to define the changes after azathioprine reduction or withdrawal.

Anemia↗
PubMed1993

Limitations of kinetic models as predictors of nutritional and dialysis adequacy in continuous ambulatory peritoneal dialysis patients.

Nutrition has been shown to predict clinical outcome in continuous ambulatory peritoneal dialysis (CAPD) patients. However, despite the positive relationship between KT/V (urea) and the normalised protein catabolic rate, the ability of urea kinetic modelling to predict clinical outcome or nutrition remains inconclusive. We have evaluated the relationship between nutrition and achieved dialysis in a cross-sectional study of 147 stable CAPD patients on dialysis for a mean period of 22 months. Protein-energy malnutrition was present in 22-32% of the study population. 39 and 41% of the population failed to achieve suggested adequacy targets of 50 liters/week for total creatinine clearance and a weekly KT/V (urea) of 1.7, respectively. Severely malnourished patients had significantly greater normalised clearance and adequacy values than well-nourished patients. Intrinsic actual peritoneal clearance bore no relation to patient size. The subsequent normalisation of this value by a component of patient mass results in a mathematical bias against well-nourished or obese patients. This may explain the failure of such adequacy values to reflect outcome and argues against accepting such values as measures of dialysis well-being.

Body Weight↗
PubMed1993

Effect of radiotherapy on peritoneal function in continuous ambulatory peritoneal dialysis.

A 25-year-old male patient underwent abdominal radiotherapy following the discovery of lymphadenopathy associated with a testicular teratoma. Prior to treatment, his peritoneal mass transfer area coefficients were within normal limits. One and 2 months after treatment, peritoneal permeability had increased to the extent that continuous ambulatory peritoneal dialysis was rendered impractical.

Adult↗
PubMed1993

Simultaneous occurrence of IgA nephropathy and sarcoidosis in the context of pre-existent minimal change nephrotic syndrome.

Simultaneous occurrence of IgA nephropathy and sarcoidosis is described in a 42-year-old Asian female, who earlier had a steroid-resistant, no light microscopy change nephrotic syndrome that resolved spontaneously. Occurrence of three, apparently unrelated conditions in this case may be fortuitous, or causally related. We discuss the possible causal relationship amongst these conditions.

Adult↗
PubMed1993

Single daily overnight (12-h dwell) use of 7.5% glucose polymer (Mw 18700; Mn 7300) +0.35% glucose solution: a 3-month study.

The osmotic effectiveness of an isosmolar glucose polymer (GP) solution during long-dwell (8-12 h) peritoneal dialysis has been demonstrated. The absorption of GP, though only a fraction of currently used glucose, is usually accompanied by the systemic accumulation of its breakdown product, maltose. The long-term consequences of maltose accumulation remain unknown. We studied the accumulation pattern of GP fractions, changes in serum electrolytes, osmolality, and adverse reaction profile over a 3-month period using a daily regime of an overnight exchange of 7.5% GP+0.35% glucose solution with three daytime exchanges of 1.36% glucose in five non-diabetic CAPD patients. The GP solution (299 +/- 0.7 mOsm/kg) produced mean daily overnight UF of 589 ml and maintained stable serum biochemistry. The mean serum maltose level increased from a predialysis value of 0.03 +/- 0.08 g/l to a steady-state level of 1.1 +/- 0.14 g/l within 2 weeks and remained stable throughout the study. This did not influence serum osmolality or sodium and produced no significant adverse effects. Once-daily overnight use of an isosmolar GP solution is safe and effective. The accumulation of maltose reaches steady-state levels quickly and produces no adverse toxic effects in the short term. Further long-term studies are planned.

Adult↗
PubMed1993

Vitamin D therapy in CAPD: what is its role?

Recognition of the harmful effects of aluminum, its replacement by calcium salts, the introduction of reduced calcium dialysis fluid, and the availability of sensitive and specific assays for intact 1-84PTH have resulted in changes in the monitoring and management of renal osteodystrophy in continuous ambulatory peritoneal dialysis (CAPD). In addition, better understanding of the calcitriol/parathyroid axis enables a more structured approach to the treatment of patients with established hyperparathyroid bone disease. Wherever possible, CAPD patients should undergo tetracycline labeled bone biopsy at the time of starting dialysis in order to establish the exact bone histology. Thereafter management can be rationally decided on the basis of regular monitoring of serum intact parathyroid hormone (iPTH). Routine prophylactic use of calcitriol is unnecessary, but when iPTH levels rise, despite strict control of calcium and phosphate levels, oral pulse therapy is an effective and inexpensive method of controlling hyperparathyroidism. However, long-term histological studies of its benefit are awaited.

Administration, Oral↗
PubMed1993

Monitoring of iron requirements in renal patients on erythropoietin.

We studied 38 patients (9 haemodialysis, 18 peritoneal dialysis, 11 advanced renal failure) over the first 12 weeks of erythropoietin therapy. In 14 iron-overloaded patients (ferritin > 500 micrograms/l the haemoglobin (+/- SEM) increased from 6.74 +/- 0.27 to 9.85 +/- 0.36 g/dl (P < 0.0001) entirely by mobilizing iron reserves (reduced from 1,220 +/- 73 to 739 +/- 111 mg, P < 0.0001). In the 24 non-overloaded patients (ferritin < 500 micrograms/l) the haemoglobin rose similarly from 7.04 +/- 0.18 to 10.70 +/- 0.36 g/dl (P < 0.0001), partly from iron reserves (depleted from 200 +/- 74 to -44 +/- 77 mg, P = 0.016) and partly from oral iron supplements (305 +/- 110 mg). In the overloaded patients the ferritin declined from 1057 micrograms/l (geometric mean, range 504-3699) to 317 micrograms/l (42-1505, P < 0.0001). In the non-overloaded patients it declined from 82 micrograms/l (8-461) to 45 micrograms/l (5-379, P = 0.016). The transferrin saturation (TS) in the overloaded patients appeared to decline from 38.3 +/- 7.2% to 24.0 +/- 3.7% but this was not statistically significant. In the non-overloaded the TS was unchanged (23.3 +/- 2.4 before and 28.1 +/- 3.6% after treatment). Considering all 38 patients together, the haemoglobin correlated negatively with the ferritin (r = 0.3731, P < 0.001) but not with the TS. The TS correlated with the serum ferritin initially (r = 0.75, P < 0.001) but not after the first 4 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Calcium and magnesium mass transfer in peritoneal dialysis patients using 1.25 mmol/L calcium, 0.25 mmol/L magnesium dialysis fluid.

OBJECTIVE: To examine the effect of a reduced calcium/magnesium dialysis fluid (1.25/0.25 mmol/L, respectively) on calcium and magnesium mass transfer in both 1.36% and 3.86% glucose solutions. DESIGN: Each patient underwent four test exchanges, two with a standard dialysis fluid containing 1.36% and 3.86% glucose, and two with a reduced calcium/magnesium fluid containing 1.36% and 3.86% glucose. Calcium and magnesium were measured in dialysate and serum at 0 and 240 minutes. SETTING: Single renal unit of a university teaching hospital. PATIENTS: Sixteen patients established on CAPD, and peritonitis-free, for at least 3 months. RESULTS: A lower dialysate calcium results in negative mass transfer when serum-ionized calcium exceeds dialysate calcium (mean -0.21 +/- 0.15 mmol/exchange), and positive mass transfer when serum-ionized calcium is less than dialysate calcium in 1.36% glucose solutions (mean 0.57 +/- 0.18 mmol/exchange). A negative correlation was found between serum-ionized calcium level and calcium mass transfer. With a 3.86% reduced calcium/magnesium solution, calcium mass transfer is always negative (-0.88 +/- 0.18 mmol/exchange) due to ultrafiltration and solute drag. Fifteen patients were found to be hypermagnesemic at the time of the study. Magnesium mass transfer was neutral with the standard 1.36% glucose fluid (mean -0.01 mmol/exchange), but negative with the reduced calcium/magnesium 1.36% glucose fluid (mean -0.58 +/- 0.13 mmol/exchange). With the 3.86% glucose solution, both fluids produced negative magnesium mass transfer (mean -0.32 +/- 0.11 and -1.07 +/- 0.11 mmol/exchange for standard and reduced calcium/magnesium fluids, respectively). CONCLUSIONS: We conclude that this fluid formulation should reduce hypercalcemia and hypermagnesemia in CAPD patients.

Adult↗
PubMed1993

Value of thallium myocardial imaging in the prediction of future cardiovascular events in patients with end-stage renal failure.

Chronic renal failure is associated with an increased rate of premature death from cardiovascular disease. Non-invasive identification of asymptomatic cardiac disease should be valuable in the management of such patients, and in selection for transplantation. One hundred and three high-risk patients (66 male, 37 female) with chronic renal failure who were without cardiovascular symptoms were assessed by exercise-graded thallium myocardial perfusion imaging and followed prospectively for 4 years. The development of a cardiovascular event, or death, and the interval to event or death were recorded. Cardiovascular events were documented in 50 patients; in 44 of the 60 patients with a positive thallium test and in only six of the 43 patients with a negative thallium test (test sensitivity 88%, specificity 70%, predictive value of a positive test 73%). Forty patients died, 28 from cardiovascular causes, during the study period. Thallium myocardial perfusion imaging is of value in the prediction of future cardiovascular events in patients with chronic renal failure, and is a useful non-invasive screening technique in patients with end-stage renal failure being considered for transplantation.

Adult↗
PubMed1993

Influence of blood volume on the blood pressure of predialysis and peritoneal dialysis patients treated with erythropoietin.

Twenty-seven patients with renal failure (16 on CAPD and 11 predialysis) were treated with erythropoietin. At 12 weeks, the mean haemoglobin concentration (+/- SEM) in the CAPD patients had increased from 7.07 +/- 0.20 to 10.88 +/- 0.45 g/dl (two-tailed paired t test, P < 0.0001) and in the predialysis patients from 6.90 +/- 0.35 to 10.05 +/- 0.47 g/dl (P < 0.0001). Predialysis patients were taking more antihypertensive medication at baseline. No increase was required in either group after erythropoietin; there was no change in blood pressure in the CAPD patients, though in the predialysis patients the systolic blood pressure rose slightly from 132 to 146 mmHg (P = 0.029) and the mean blood pressure from 95 to 103 mmHg (P = 0.028). In 12 patients (6 on CAPD and 6 predialysis) the red cell volume, plasma volume, and total blood volume were measured before and after treatment. In the CAPD patients there was a marked expansion of the red cell volume from 912 +/- 127 to 1471 +/- 222 ml (P = 0.004) and a concomitant contraction of the plasma volume from 3932 +/- 250 to 3178 +/- 326 ml (P = 0.005), leaving the blood volume unchanged from 4843 +/- 352 to 4649 +/- 503 ml. Predialysis patients had a similar expansion of the red cell volume from 733 +/- 59 to 1304 +/- 161 ml (P = 0.017) but no contraction of the plasma volume (from 3417 +/- 354 to 3314 +/- 260 ml), so that the blood volume tended to expand from 4149 +/- 347 to 4618 +/- 414 ml (P = 0.053).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed1993

Peritoneal dialysis-related peritonitis treatment recommendations. 1993 update. The Ad Hoc Advisory Committee on Peritonitis Management. International Society for Peritoneal Dialysis.

In conclusion, the recommendations provided in this document represent a distillation of various experiences, as well as data obtained from published studies. It is hoped that this compilation will provide a basis upon which future developments and advances can be made in the therapeutic approach to infectious complications of peritoneal dialysis.

Anti-Bacterial Agents↗
PubMed1993

Peritoneal catheters and exit-site practices: toward optimum peritoneal access.

The peritoneal catheter is the CAPD patient's lifeline. Advances in catheter knowledge have made it possible to access the peritoneal cavity safely and maintain access over an extended period of time. Infection at the exit site remains a major problem, a solution for which is being extensively researched. The successful outcome of a catheter in an individual depends on meticulous care and adherence to sound principles of catheter insertion and management. The guidelines provided in this publication represent the consensus based on the extensive experience of several major centers worldwide.

Catheters, Indwelling↗