Time to target haemoglobin concentration (11 g/dl)--risk of hospitalization and mortality among incident dialysis patients.

BACKGROUND: Haemoglobin levels <11 g/dl are associated with increased costs, morbidity and mortality. We aimed to determine if time required to reach 11 g/dl was associated with increased risk of hospitalization or death among incident dialysis patients. METHODS: We studied 29 131 patients initiating dialysis in 2002 and surviving >or=9 months. Demographic, comorbid and health care use data were extracted from Medicare claims from months 4-9 post-dialysis initiation. Logistic regression was used to calculate a propensity score for odds of longer than mean time to target. Proportional hazard models were used to assess effects of longer time on hospitalization and death. Other models were stratified for quartile of propensity score. RESULTS: Mean time to target haemoglobin was 1.3 months and 36% of participants required longer. These were more likely to be younger and minority, to use a dialysis catheter, and to have more comorbidity and hospitalization days during the entry period. Longer time to target was associated with increased risk for hospitalization (hazards ratio 1.15; 95% confidence interval 1.12-1.19) and mortality (1.26; 1.20-1.33) in the following year. Associations did not change when stratified by quartile of propensity score. CONCLUSIONS: Longer time required to reach the target haemoglobin level was associated with significantly higher risk of hospitalization and mortality. Whether observed associations resulted from residual confounding by more severe illness remains unclear. Future trials should determine if rapidity of haemoglobin correction influences outcomes.     

A Mysterious Extrafraction in the Gamma Area of Protein Electrophoresis in Dialysis Patients is Found to be Fibrinogen

The appearance of a heretofore unnoticed extrafraction in the gamma protein electrophoresis of 17 dialyzed patients was linked to the modified Shaldon dialysis catheter. Medication interference, infection, and immunological or hematological disease as causative factors were ruled out. After initial contradictory results, the extrafraction was determined to be fibrinogen, present because of the slow release of heparin contained in the catheter, so that electrophoresis was performed on plasma instead of on serum.     

Lack of effect of prenalterol on dialysis — Associated hypotension

Summary Prenalterol, a cardio selective beta adrenergic receptor antagonist was given perorally in doses from 20–150 mg/day in three patients with dialysis associated hypotension. No effect on blood-pressure was seen over several months during this treatment.     

Correction of subclinical ascorbate deficiency in patients receiving dialysis: Effects on plasma oxalate, serum cholesterol, and capillary fragility

Whole blood ascorbate, plasma oxalate, serum cholesterol, and capillary fragility were measured at monthly intervals for 3 mth in 7 patients receiving continuous ambulatory peritoneal dialysis and 4 receiving haemodialysis, to whom ascorbate supplements had not been prescribed for at least 12 mth. Ascorbate supplements, 25 mg/day, were prescribed for the first month and 50 mg/day for the second month; in the final month patients received no supplements. Whole blood ascorbate was below normal in 6/11 patients at the start of the study but was normal in 10/11 patients when taking ascorbate 50 mg/day. No significant changes in plasma oxalate were observed with these doses of ascorbate, and correction of ascorbate deficiency had no effect on serum cholesterol, mean cell volume, or the results of capillary fragility tests.

In a supplementary study, ascorbic acid 500 mg/day was administered for 3 wk to 11 patients. This resulted in a significant rise in mean plasma oxalate from 30.3 (SEM 3.5) to 48.4 (SEM 20.3) μmol/l.     

Effects of Bicarbonate-Containing versus Lactate-Containing Peritoneal Dialysis Solutions on Superoxide Production by Human Neutrophils

Human neutrophils were isolated from healthy volunteers and exposed to either bicarbonate-containing (pH 7.4) or lactate-containing (pH 5.2) peritoneal dialysis solution in vitro. Superoxide production by neutrophils was measured by a method based on the superoxide dismutase-inhibitable reduction of ferricytochrome c. Bicarbonate-containing peritoneal dialysis solution was found to be superior to the lactate-containing one in facilitating the production of superoxide anion by human neutrophils.     

Pressure Control of Ultrafiltration Rate with High-Flux Dialysis Membranes

Control of ultrafiltration with high-flux dialysis membranes is normally achieved using complex, expensive, volumetric control methods. By using high-flux dialyzers with distensible membranes (parallel-plate dialyzers) in the cocurrent rather than in the countercurrent mode, ultrafiltration can be controlled simply and inexpensively by controlling the outlet pressure differential. Since this is the traditional method of ultrafiltration control, only minor, inexpensive equipment modifications are needed. As expected from transport theory, small molecule clearances are lower with cocurrent than with countercurrent flow. They are, however, adequate and superior to those achieved with post-dilutional hemofiltration (urea clearance > 110 ml/min with cocurrent single-pass, high-flux dialysis). Ultrafiltration control with this method is so simple and predictable that clearances at zero net ultrafiltration rates can easily be measured rather than extrapolated. Since dialysate pressure is always positive, no deaeration systems would be needed in dialysis equipment designed for use with co-current single-pass, high-flux dialysis.     

Oral aluminum and neuropsychological functioning

Summary Nine dialysis patients with significantly increased serum-aluminum levels due to chronic ingestion of aluminum hydroxide gels and eleven dialysis patients with normal serum-aluminum levels were tested neuropsychologically for generalized functions (intelligence, reasoning, memory) and for more specific abilities (visual memory, verbal and reading fluency, manual dexterity). All tests did not reveal any significant difference in neuropsychological functioning between the two groups. This finding seems to indicate that oral aluminum is not neurotoxic for man, even under circumstance of renal failure. This contradicts the idea that oral aluminum plays a role in the etiology of dialysis dementia. However, the possibility cannot be excluded that aluminum overload in the present sample was not sufficient to induce changes in CNS functioning. Thus, until the importance of oral aluminum has been decided, it seems wise to keep all sources of aluminum overload as low as possible.Part of this investigation was presented at the XVI EDTA Congress, Amsterdam, June 1979, and at the XXI Congress of the Italian Society of Neurology, Catania, November 1979     

MINOCYCLINE EXCRETION AND DISTRIBUTION IN RELATION TO RENAL FUNCTION IN MAN

SUMMARY 1. The biological half-life of minocycline in serum has been studied in twenty-one patients and shown to have no relationship to renal function. There is very little excretion of minocycline by the kidney, and practically none is removed by dialysis.
2. In normal subjects, minocycline therapy is not accompanied by a significant rise in blood urea concentration or urinary urea excretion. However, high doses may produce a marked increase in urea excretion.
3. Of eight patients with impaired renal function who were treated with a normal therapeutic dose of minocycline (200 mg/day), one showed a significant increase in urea excretion and a rise in plasma urea concentration. Two patients with severe unstable renal failure required dialysis following therapy.
4. Minocycline is unlikely to accumulate in patients with renal failure due to its predominantly gastrointestinal excretion and is therefore safe to use. However, its protein catabolic effect is dose dependent and if renal function is impaired, even a small increase in urea production may be sufficient to aggravate uraemia. In such patients the normal therapeutic dose (200 mg/day) should not be exceeded and monitoring of renal function is advisable.     

基于血清蛋白的沙蟾毒精与盐酸维拉帕米相互作用研究

目的：研究沙蟾毒精和盐酸维拉帕米与血清蛋白的结合及两者间的相互影响。方法：采用平衡透析法和高效液相色谱法测定两种药物与小牛血清蛋白的结合率。荧光光谱法研究沙蟾毒精与牛血清白蛋白和人血清白蛋白（human serumalbumin,HSA）的相互作用,并采用分子对接模拟药物相互作用模式。结果：0.1μg/mL沙蟾毒精与小牛血清蛋白结合率为（61.1±0.2）%,加入不同浓度盐酸维拉帕米后,沙蟾毒精的血清蛋白结合率显著下降,从（61.1±0.2）%下降到（36.9±3.4）%。测得盐酸维拉帕米（2μg/mL）的血清蛋白结合率为（87.5±0.5）%;当加入不同浓度沙蟾毒精后,盐酸维拉帕米血清蛋白结合率无显著变化。荧光光谱检测表明盐酸维拉帕米能够抑制沙蟾毒精与血清白蛋白的结合。分子对接结果表明,沙蟾毒精、盐酸维拉帕米竞争性结合HSA的位点Ⅰ,盐酸维拉帕米与位点Ⅰ的分子结合能力大于沙蟾毒精,置换沙蟾毒精与HSA在位点Ⅰ的结合。结论：盐酸维拉帕米能够抑制沙蟾毒精与血清蛋白及白蛋白的结合。