Aluminium speciation in cerebrospinal fluid of acutely aluminium-intoxicated dialysis patients before and after desferrioxamine treatment; a step in the understanding of the element's neurotoxicity.

BACKGROUND: The association between aluminium and dialysis encephalopathy and deterioration of the neurological state during desferrioxamine treatment of dialysis patients is well established. At present little is known about the speciation and the mechanisms underlying the element's neurotoxicity. METHODS: Aluminium speciation was performed in cerebrospinal fluid samples of acutely aluminium-intoxicated dialysis patients using a recently developed high-performance liquid chromatographic/electrothermal atomic absorption spectrometric hybrid method. RESULTS: Baseline cerebrospinal fluid aluminium levels of samples taken shortly after the intoxication were low but elevated (5.0 +/- 2.0 micrograms/l, n = 3) as compared to subjects with normal renal function (< 1 microgram/l). In contrast to the situation noted in serum and to the iron speciation in cerebrospinal fluid, aluminium was not bound to transferrin but appeared as two distinct compounds, the main fraction eluting at the elution volume of aluminium-citrate/silicate. The second compound was not identified. Forty-four hours after desferrioxamine administration the cerebrospinal fluid aluminium levels had increased up to a concentration of 10.3 +/- 2.5 micrograms/l (n = 3). This was accompanied by a change in the speciation profile with aluminium appearing at the elution volume of aluminoxamine. CONCLUSIONS: Our findings may contribute to a better understanding of the neurotoxic effects of aluminium and its desferrioxamine chelate in dialysis patients.

Low-dose (5 mg/kg) desferrioxamine treatment in acutely aluminium-intoxicated haemodialysis patients using two drug administration schedules.

BACKGROUND: According to the recommendations proposed at The Consensus Conference on Diagnosis and Treatment of Aluminium Overload in End-Stage Renal Failure Patients, Paris, 1992 low-dose desferrioxamine (DFO) treatment was applied for the first time in 41 acutely aluminium-intoxicated patients. METHODS AND RESULTS: DFO-related neurological/ophthalmological side-effects were observed in nine of 11 patients with a post-DFO serum aluminium level > 300 micrograms/litre and in two patients of 30 below this level after a single administration of a 5-mg/kg dose of the chelator in the conventional way (i.e. the last hour of a dialysis session). They were no longer observed after introducing an alternative DFO administration schedule (i.e. administration of the chelator 5 h prior to the start of a haemodialysis session; group I: n = 14). A significant decrease in the serum aluminium levels as well as in the post-DFO serum aluminium increment (delta s A1) was observed during the first 6 months, course of low-dose DFO treatment in group I as well as group II (which consisted of patients receiving DFO in the conventional way; n = 27). Low-dose DFO treatment was accompanied by a significant increase in the mean +/- SD serum iPTH levels (group I: 174 +/- 245 up to 286 +/- 285 ng/litre; group II: 206 +/- 272 up to 409 +/- 424 ng/litre; P < 0.005) and the mean corpuscular volume (group I: 80 +/- 6.4 up to 85 +/- 3.7 fL, P < 0.005; group II: 76 +/- 5.0 up to 87 +/- 4.3 fL, (P < 0.0001). Serum ferritin levels significantly decreased in both groups. No further side-effects were observed during the DFO course. Patients in which DFO treatment could be stopped (i.e. subjects in which both serum aluminium and delta sA1 were below 50 micrograms/litre at two successive occasions) before the end of the 6 months' treatment course had a significantly greater residual diuresis (700 +/- 682 ml/min vs 84 +/- 109 ml/24 h). Also, residual diuresis was found to protect against aluminium intoxication as reflected by the values noted in group I versus those in group II. CONCLUSION: The 5-mg/kg DFO treatment provides a safe and adequate therapy for aluminium overload. In severely aluminium-intoxicated patients presenting post-DFO serum aluminium levels above 300 micrograms/litre DFO should be given once weekly 5 h prior to high-extraction dialysis ensuring (i) maximal chelation of aluminium (ii) limited exposure to circulating aluminium noxamine levels, and (iii) adequate removal of the latter compound. Finally, the necessity for a better communication between the local water distribution companies and the dialysis centres is a major lesson that can be drawn from this dramatic intoxication.

[Hemodialysis with bicarbonate 30 mEq/l versus 34 mEq/l and acetate: better hemodynamic tolerance and electrolyte and acid-base homeostasis]. / Hemodiálise com bicarbonato 30 mEq/l versus 34 mEq/l e acetato: a melhor tolerância hemodinâmica e homeostasia electrolítica e ácido-base.

The use of bicarbonate buffer in dialysis is more physiological than acetate. The aim of this prospective study was to compare the hemodynamic stability, acid-base and electrolyte balance changes in a group of 5 hospital hemodialysis (HD) patients, with 3 different dialysis fluids: one with 30 mEq/l of bicarbonate (B30), another with 34 mEq/l of bicarbonate (B34) and the last with acetate (ACE). All the patients had more than 12 months in HD. Each patient had HD treatment with one of the 3 different dialysis fluids: ACE, B30, B34. Each HD had a duration of 4 hours, with less than 5% dry weight ultrafiltration (UF) and continuous cardiac monitoring. The following clinical and laboratory data were evaluated: arterial blood pressure (BP), cardiac rate (CR), respiratory rate (RR), cardiac arrhythmias, blood urea, creatinine, sodium, potassium, magnesium, total calcium (Ca), ionised calcium (Ca++), pH, bicarbonate (HCO3-) and pCO2. Statistic analysis was performed using Student's paired t test and ANOVA with Bonferroni correction. Clinical evaluation showed a CR increase only in the ACE group (pre X = 78.4 to 4 degrees h X = 102.6 p < 0.001). Analytical results demonstrated, at the 1st h, Ca++ stability in the B30 group; in the first 30' the pH decreased in the ACE group (pre X = 7.35 to 30' X = 7.34); during HD, HCO3- was not corrected in the ACE group (pre X = 19.4 to 4th h X = 20.0); at 4th, pCO2 also decreased in this group (pre X = 34.5 to 4th h X = 28.4 p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

[Identification of a period of renal ischemic vulnerability studying the changes in the indicators of acute renal insufficiency after heart surgery with extracorporeal circulation]. / Identificação de um período de vulnerabilidade isquémica renal pelo estudo da evolução dos indicadores de insuficiência renal aguda após cirurgia cardíaca sob circulação extra corporal.

We studied the pre operative status and the 1st, 4th, 12th and 24th hours of the post operative period after open heart surgery with cardiopulmonary bypass with a crystalloid solution containing 10 gr of mannitol. We considered acute renal failure (ARF) as being any increase in plasma creatinine values of 0.25 mg/dl for the first 24 hours and 0.5 mg/dl for periods longer than 24 hours. Six patients had transitory ARF (28.5%). The maximum value of plasma creatinine was 2.3 mg/dl and no patients required renal function substitution. There were no deaths. We used as ischemia ARF indicators the urinary flow rate, urine/plasma creatinine ratio, urine/plasma osmolality ratio, sodium fractional excretion and free water reabsorption. We also measured the urinary N-A-Glucosaminidase (NAG). We found that creatinine clearance reached its lowest in the first and fourth hours. Beyond the fourth hour we observed, the urinary flow rate reduce significantly, the urine/plasma creatinine and osmolality ratios reach values traditionally associated prerenal ARF, an increase main free water reabsorption and a decrease in sodium fractional excretion with a close relationship between the less than 1 value and the increase in plasma creatinine. There was a significant NAG increase in the 24 th hour. The evidence of a vulnerability period for renal ischemic lesions between the 4 th and 12 th hour suggests a second mannitol administration during the first four hours of the post operative period.

[Prevention of thrombogenesis in the extracorporeal circuit of hemodialysis with a low molecular heparin: standardization of the dosage with a better hemorrhagic risk/effectiveness ratio]. / Prevenção da trombogénese no circuito extracorporal de hemodiálise com uma heparina de baixo peso molecular: padronização da dose com melhor relação risco hemorrágico/eficácia operacional.

PURPOSE: To test the efficacy and safety of a low molecular. Weight heparin (LMWH)--Fraxiparine, for hemodialysis (HD) anticoagulation, compared with conventional heparin (H) or serum lavage without other anticoagulation (L). DESIGN: Prospective controlled study. PATIENTS AND METHODS: Twenty-nine consecutive patients referred for dialysis in a tertiary care hospital were divided in 3 groups A, B and C, each group A and B patient submitted to 2 dialysis, AI and AII, BI and BII. Group A--n = 10, no bleeding risk, single needle technique, blood flow (Qb) less than 200 ml/min. HD-AI used LMWH 10,000 U pre-HD, HD-AII used H for an ACT 1.5 to 2 times baseline; group B--n = 10, high bleeding risk, double needle dialysis, Qb--200 to 300 ml/min. HD-BI used LMWH 5000 U pre-HD, and HD-BII used only L; Group C--n = 9, no bleeding risk, Qb less than 200 ml/min, all received LMWH 5000 U pre-HD. A semiquantitative screening was done in each dialysis for the presence of dialyser or venous chamber clots, APTT and Anti Xa activity were measured every 30 min., as well as pre and post-dialysis Hb, Htc, and platelets. RESULTS: APTT didn't rise significantly during HD with LMWH in contrast with the AII group with H (32.2 +/- 7.1 vs 63 +/- 25.8, p less than 0.05). The APTT levels in all dialysis with LMWH were identical to BII dialysis With L. Anti xa activity had an early peak at 30 to 60 min. With LMWH (0.62 +/- 0.45 em AI) and a late one at 180 min with H (0.39 +/- 0.2). There was no significant differences between pre and post-dialysis corrected platelet counts, but the lavage group showed the greater decrements (-20% +/- 24). In all the 49 dialysis we had 5 cases of complete clotting of the blood circuit, all of them in the lavage group C. No patients with high risk of hemorrhage had any bleeding increment. CONCLUSION: LMWH prevents clotting as effectively as H, in low doses of 5000 anti Xa units it doesn't interfere with PTT and is far more effective than HD with serum lavage in patients with bleeding risk and/or low blood flow in the dialysis circuit.

[Hydro-electrolyte changes induced by transurethral prostatic resection]. / Alterações hidro-electrolíticas induzidas por ressecção prostática transuretral.

Transurethral resection prostatectomy (TURP) has been associated with severe hyponatremia due to massive absorption of bladder irrigation fluid (IF). TURP was performed in 41 patients using Sorbitol-Mannitol IF (Group A) and in 6 patients using distilled water (Group B). Six other patients were operated upon using surgical procedures identical in time and type of anesthesia to TURP (Group C). The three groups were studied with the same protocol that included blood collected before (time I), immediately after (time II) the procedure and 1 hour later (time III). Serum sodium decreased significantly in the 3 groups from time I to time II, an average of 3.4 mEq/l with Mannitol-Sorbitol, 2.3 mEq/l with distilled water, and 4.4 mEq/l in group C. Osmolality did not change significantly between the 3 times of collection and Osmolar Gap only increased from time I to II in the Sorbitol-Mannitol group. In conclusion, mild decrements in serum sodium with no clinical relevance are a common post-TURP finding, but should not be greater than in other similar general surgery without bladder irrigation. Hyposmolality did not constitute a problem.

Antihypertensive action of calcium blockade in hypertensive patients with chronic renal disease.

The concentration of ionic calcium (Ca2+ in the smooth muscular cells of the resistance vessels is a determining factor of their contraction. It depends on the influx of Ca2+ to the interior of the cells through the calcium channels in the sarcolemma. The effect of a specific Ca2+-channel blocking agent - nifedipine - on arterial hypertension in a group of 18 patients with chronic renal hypertension is reported in this study. The combination of nifedipine and propranolol in the control of hypertension in 6 of these patients in a long-term follow-up was also studied. It was concluded: (1) Ca2+ blockade had a rapid and powerful antihypertensive effect in all patients; (2) the antihypertensive effect was higher with high initial blood pressure levels; this fact was especially evident and appeared particularly useful in hypertensive emergencies; (3) in some patients, the action of nifedipine was dose-dependent; (4) nifedipine had a short-lived action; (5) the combination nifedipine-propranolol was efficient in the long-term control of hypertension.

Interference of heparin with peritoneal solute transport.

To verify the action of heparin on peritoneal transport, we selected 20 patients on acute peritoneal dialysis and performed two 2-hour cycles with 2,000 cm3 of a 1.5% solution, adding 2,000 units of heparin to the second cycle. The patients were also randomized into 2 groups: group A, adding 1.5 mg gentamycin/kg to the dialysate of cycle I (without heparin), and group B, adding the same dose of gentamycin to cycle II (with heparin). At the end of each of the two cycles blood and dialysate were drawn for urea, creatinine, glucose, proteins and gentamycin levels, using peritoneal clearances of urea and creatinine, glucose absorption and net protein loss to compare cycle I with cycle II. We found that the peritoneal transport of creatinine and urea was improved (p less than 0.02; p less than 0.05) and glucose absorption increased (p less than 0.01) with heparin, without any significant change in protein loss. Contrary to common belief, heparin in a 1,000-U/l dose improved the absorption of gentamycin from the dialysate (p less than 0.01).