Serum aluminium concentration and aluminium deposits in bone in patients receiving haemodialysis.

Serum aluminium concentrations and biopsy specimens of bone were examined in 56 patients with end stage chronic renal failure receiving maintenance haemodialysis. Deposits of aluminium in bone specimens were often associated with low bone formation with or without osteomalacia. Serum aluminium concentrations of greater than 3.7 mumol/l (10 micrograms/100 ml) indicated a high probability of deposits of aluminium in bone specimens, although high serum concentrations did not predict the type of renal bone disease. Biopsy of the bone is the best method of detecting aluminium intoxication of bone. A serum aluminium concentration of 3.7 mumol/l should be the threshold beyond which bone biopsy should be performed to confirm an overload of aluminium and identify histological bone changes induced by aluminium.     

Heat inhibition of in vitro lipolysis and 14C ibuprofen protein binding in plasma from heparinized uraemic subjects

Protein binding determination in post heparin plasma samples is complicated by the continued post heparin lipase activity, in vitro, during the binding analysis. The decomposition of lipoproteins and accumulation of nonesterified fatty acids (NEFA) results in artifically elevated free fractions of many drugs. This artefact is particularly accentuated in haemodialysis patients who are frequently hypertriglyceridaemic and receive large doses of heparin. Rapid heat treatment (60 degrees for 15 min) of plasma from heparinized uraemic subjects is shown to inhibit the in vitro lipolysis occurring during 2 hours of equilibrium dialysis at 37 degrees (ED). Mean NEFA concentrations in heat treated plasma after ED (means = 400 +/- 141 mumol/L) were not different (p greater than 0.05, n = 9) from the baseline values in fresh plasma (means 351 +/- 117 mumol/L) but were considerably less (p less than 0.005) than NEFA levels in untreated plasma after ED (means = 1025 +/- 523 mumol/L). The degree of in vitro lipolysis inhibition (92 +/- 6.6%) was very much greater than using the chemical inhibitors phenyl methyl sulphonyl fluoride, EDTA, Triton X100 or protamine sulphate. Heat treatment at 60 degrees for 15 min increased the percentage of free 14C ibuprofen in 3.5% isolated human serum albumin from 0.34% to 0.62%. Reduced binding as a result of heat treatment was not observed however in whole plasma. The percentage free ibuprofen in heat treated, whole plasma from both heparinized and non heparinized subjects (means = 1.22 +/- 0.19; n = 29) was not different (p greater than 0.05) from the percentage free determined in plasma from a non heparinized group (means = 1.16 +/- 0.23; n = 15). In contrast the % free ibuprofen in untreated plasma from heparinized subjects was markedly higher (means = 1.56 +/- 0.41; n = 24; p less than 0.05). There was a strong correlation between % free ibuprofen and plasma NEFA concentration (r = 0.8; p less than 0.005; n = 68). The heat treatment of plasma for 15 min at 60 degrees is proposed as an effective means of controlling heparin induced lipolysis in vitro and may be valuable in overcoming the post heparin binding artefact.     

Composition of the domestic water supply and the incidence of fractures and encephalopathy in patients on home dialysis.

Of the 202 patients undergoing home dialysis in the Trent region, 11 developed dialysis encephalopathy, 21 suffered spontaneous fractures, and 36 who had undergone dialysis for over four years had neither of these complications. Because the incidence of complications seemed to be unevenly distributed the water supplies were analysed. Water supplied to the homes of the patients with fractures or encephalopathy contained significantly less calcium and fluorine and significantly more aluminium and manganese than that piped to patients without these complications. The high aluminium concentrations in the bone of patients with encephalopathy was confirmed, but aluminium concentrations in the brains from three patients with encephalopathy were not increased. Patients who undergo dialysis in areas where water contains high aluminium concentrations should be supplied with deionisers.     

Effect of aluminium hydroxide on serum ionised calcium,immunoreactive parathyroid hormone,and aluminium in chronic renal failure.

According to the Bricker-Slatopolsky theory, secretion of parathyroid hormone (PTH) is switched on in chronic renal failure by hypocalcaemia due to phosphate retention. In an attempt to reverse this process 20 patients in preterminal renal failure (plasma creatinine 569 +/- 195 mumol/l) were given aluminium hydroxide, 3.8 g daily. They were studied for four weeks and all measurements were made at the start and weekly, except measurements of serum aluminium concentration, which were made at the start and at the end of the fourth week. Mean serum phosphate fell from 1.89 to 1.47 mmol/l (5.9 to 4.6 mg/100), mean serum calcium rose from 2.07 to 2.24 mmol/l (8.3 to 9.0 mg/100 ml), and serum ionised calcium rose from 1.07 to 1.20 mmol/l (4.3 to 4.8 mg/100 ml), but serum immunoreactive PTH did not fall. Thirteen patients had initial serum immunoreactive PTH concentrations at or near to normal and 11 were taking beta-blockers but even in those with neither explanation, PTH concentrations did not fall. Serum aluminium concentrations rose from 0.4 to 1.02 mumol/l (10.9 to 27.4 microgram/l). Aluminium hydroxide corrects serum phosphate, total calcium, and ionised calcium at the price of a rise in serum aluminium concentration; in this study it did not affect serum immunoreactive PTH. The Bricker-Slatopolsky theory still needs verification in studies of patients with chronic renal failure.     

Continuous ambulatory peritoneal dialysis: one year's experience in a UK dialysis unit.

Thirty-two patients aged 8-63 years trained to manage themselves by continuous ambulatory peritoneal dialysis for end-stage renal failure achieved better steady-state serum biochemistry and much higher haemoglobin and lower serum phosphate concentrations than during treatment with haemodialysis up to one year before. Two patients, however, returned to intermittent haemodialysis because of recurrent peritonitis. Costs of the technique during the first year were less than half those incurred in the first year of home haemodialysis. Nevertheless, the major advantage was the ease with which patient independence and rehabilitation could be achieved. This technique is an appreciable advance over other forms of management for end-stage renal failure. Nevertheless, until it is more refined and long-term problems have been assessed it should probably be used only in established renal units where back-up treatments are available.     

Vitamin A toxicity and hypercalcaemia in chronic renal failure.

Serum vitamin A concentrations were measured in 38 patients undergoing haemodialysis, 24 of whom were taking multivitamin preparations containing vitamin A. Vitamin A concentrations were significantly higher in patients undergoing haemodialysis than in 28 normal controls (p less than 0.001). Patients taking vitamin A supplements had significantly higher vitamin A concentrations than those not taking them (p less than 0.05), and hypercalcaemic patients had higher concentrations than normocalcaemic patients (p less than 0.005). Withdrawal of vitamin A supplements in seven patients caused significant falls in serum vitamin A concentrations and plasma calcium concentrations (p less than 0.01 at two and three months in both cases) and in plasma alkaline phosphatase concentrations (p less than 0.01 at two months). Vitamin A toxicity can contribute to hypercalcaemia in patients undergoing haemodialysis, probably by an osteolytic effect. Multivitamin preparations containing vitamin A should therefore be prescribed with caution in these patients.     

A radioimmunoassay for plasma dehydroepiandrosterone sulphate incorporating placental steroid sulphatase as a hydrolysing reagent

We describe a method for the measurement of plasma dehydroepiandrosterone sulphate (DHAS) which incorporates a Triton X-100 solubilised preparation of human placental steroid sulphatase as a hydrolysing agent and a direct radioimmunoassay of liberated DHA using a specific antiserum. The hydrolysis procedure is carried out at 50 degrees C for 1 h and an assay run can be completed in 4 h. As determined by the method, plasma concentrations of DHAS in 32 normal adult men (ages 23-58 yr) had a mean value +/- SD of 5.5 +/- 1.89 mumol/l. For 30 normal adult cyclic women (ages 22-35 yr) the mean plasma concentration of DHAS +/- SD was 3.1 +/- 1.35 mumol/l which was significantly lower (P less than 0.01) than found for men. Plasma DHAS concentration were also measured in 50 hirsute female patients. The mean value +/- SD was 5.03 +/- 2.52 mumol/l which was significantly higher (P less than 0.01) than the value for the normal female group. Some 42% of the hirsute patients had DHAS concentrations above the upper 95% probability limit of the normal range for premenopausal women.     

Acute Zinc Toxicity in Haemodialysis

A country patient on home haemodialysis suffered acute nausea, vomiting, and fever during dialyses when she used water stored in a galvanized tank. She subsequently was found to have severe anaemia with raised plasma and erythrocyte zinc concentrations. Intercurrent hospital haemodialyses and subsequent home dialyses with deionized water were symptom-free.Experimental haemodialyses of dogs against small concentrations of zinc showed a disproportionate rise in plasma zinc and possible uptake of zinc by the liver.     

Involvement of cytochrome a in iron oxidation of a moderately thermophilic iron-oxidizing bacterium, strain TI-1.

The iron-oxidizing activity of a moderately thermophilic iron-oxidizing bacterium, strain TI-1, was located in the plasma membrane. When the strain was grown in Fe2+ (60 mM)-salts medium containing yeast extract (0.03%), the plasma membrane had iron-oxidizing activity of 0.129 mumol O2 uptake/mg/min. Iron oxidase was solubilized from the plasma membrane with 1.0% n-octyl-beta-D-glucopyranoside (OGL) containing 25% (v/v) glycerol (pH 3.0) and purified 37-fold by a SP Sepharose FF column chromatography. Iron oxidase solubilized from the plasma membrane was stable at pH 3.0, but quite unstable in the buffer with the pH above 6.0 or below 1.0. The optimum pH and temperature for iron oxidation were 3.0 and 55 degrees C, respectively. Solubilized enzyme from the membrane showed absorption peaks characteristic of cytochromes a and b. Cyanide and azide, inhibitors of cytochrome c oxidase, completely inhibited iron-oxidizing activity at 100 microM, but antimycin A, 2-n-heptyl-4-hydroxyquinoline-N-oxide (HOQNO) and myxothiazol, inhibitors of electron transport systems involved with cytochrome b, did not inhibit enzyme activity at 10 microM. The absorption spectrum of the most active enzyme fraction from SP Sepharose FF column chromatography (4.76 mumol O2 uptake/mg/min) compared with lower active fractions from the chromatography (0.009 and 2.10 mumol O2 uptake/mg/min) showed a large alpha-peak of cytochrome a at 602 nm and a smaller alpha-peak of cytochrome b at 560 nm. The absorption spectrum of pyridine ferrohemochrome prepared from the most highly purified enzyme showed an alpha-peak characteristic of heme a at 587 nm, but not the alpha-peak characteristic of heme c at 550 nm. The cytochrome a, but not cytochrome b, in the most highly purified enzyme fraction was reduced by the addition of ferrous iron at pH 3.0, indicating that electrons from Fe2+ were transported to cytochrome a, but not cytochrome b. These results strongly suggest that cytochrome a, but not cytochromes b and c, is involved in iron oxidation of strain TI-1.     

Aluminium bone disease in patients receiving plasma exchange with contaminated albumin.

Aluminium balance studies were carried out on eight patients with various immunological disorders who were receiving plasma exchange with albumin solutions known to be contaminated with aluminium. Four patients with impaired renal function (creatinine clearance less than 50 ml/min) retained between 60% and 74% of the aluminium infused during a single plasma exchange. Transiliac bone biopsy specimens from three patients in this group had a high content of aluminium and showed histological evidence of current or previous bone disease related to aluminium. Two of these patients suffered intermittent bone pain. The main route of excretion of injected aluminium was in urine, only a small proportion of the total input being removed in the "plasma bag" during plasma exchange. The extent of aluminium retention and bone deposition was not reflected by the plasma aluminium concentration before or after plasma exchange. Treatment of five patients with intravenous desferrioxamine increased the plasma aluminium concentration and urinary output of aluminium in those with evidence of aluminium retention. These studies show that patients with poor renal function receiving treatment with albumin contaminated with aluminium retain the metal and deposit it in bone, where it may eventually cause aluminium bone disease. Plasma exchange should be used with caution in patients with renal impairment.     

Hydrazonopropionic acids, a new class of hypoglycemic substances. 4. Hypoglycemic effect of 2-(3-methyl-cinnamylhydrazono)-propionate in the rat and guinea pig

The hydrazone-compound 2-(3-methyl-cinnamylhydrazono)-propionate (MCHP) significantly lowered the blood glucose concentration in fasted guinea pigs and rats. A significant decrease of blood glucose levels was observed in fasted guinea pigs already after an intraperitoneal injection of 20.5 mumol/kg MCHP, while much higher doses (about 1000 mumol/kg) were necessary to produce a hypoglycemic effect in the fasted rat. After oral administration MCHP (82.0 mumol/kg) significantly decreased the blood glucose concentration in guinea pigs. Furthermore MCHP caused a dose-dependent increase of plasma free fatty acid concentrations in guinea pigs and rats. In addition, MCHP decreased the concentrations of blood ketone bodies, plasma cholesterol and intrahepatic acetyl-coenzyme A in the guinea pig. All of these findings appear to be due to a reduced fatty acid utilization in the presence of MCHP resulting presumably in an intramitochondrial deficiency of acetyl-CoA. At hypoglycemic effective doses the intramitochondrial and cytoplasmatic redox ratios as well as the hepatic ATP/ADP ratio were not influenced by MCHP in fasted guinea pigs. Even at large doses (123 mumol/kg) MCHP decreased the activity of monoamino oxidase in guinea pigs only by less than 15%. Furthermore MCHP showed under our experimental conditions no relevant influence on the activity of various liver enzymes in plasma, the plasma concentration of creatinine, the plasma triglyceride-glycerol level and on the intrahepatic triglyceride-glycerol concentration of fasted guinea pigs. It is concluded that MCHP meets basic requirements for a potential oral antidiabetic agent.     

Physiological plasma concentrations of cholecystokinin stimulate pancreatic enzyme secretion and gallbladder contraction in man

The present study was undertaken to determine whether infusion of cholecystokinin (CCK) to plasma concentrations comparable to those found after a meal stimulates pancreatic enzyme secretion and gallbladder contraction. Plasma CCK concentrations were measured by radioimmunoassay using antibody T204, which binds to all carboxyl-terminal CCK-peptides containing the sulfated tyrosine region. Ingestion of a standardized test meal in 7 normal subjects induced significant increases in plasma CCK from 2.0 +/- 0.2 pmol/l to levels between 4.6 +/- 0.6 and 7.3 +/- 1.0 pmol/l (p less than 0.05-p less than 0.0005). Infusion of 2.5 pmol/kg X h CCK 33 resulted in significant increases in plasma CCK from 2.0 +/- 0.2 to 3.9 +/- 0.3 pmol/l (p less than 0.0005). This infusion of CCK induced significant increases in trypsin secretion from 0.5 +/- 0.1 to 1.4 +/- 0.2 KU/15 min (p less than 0.005) and in bilirubin output from 1.6 +/- 0.7 to 30.3 +/- 8.0 mumol/15 min (p less than 0.05). It is concluded that physiological plasma concentrations of CCK stimulate pancreatic enzyme secretion and gallbladder contraction in man.     

Influence of aluminium on phosphorus and calcium localization in roots of beech (Fagus sylvatica)

Beech plants ( Fagus sylvatica L. provenance Maramures) were grown in nutrient solution at low pH (4.2) and exposed to different concentrations of AlCl₃. Uptake and leakage of Ca²⁺(⁴⁵Ca²⁺) and H²PO₄-(³²P) were studied. A high external aluminium concentration (1.0m M ) reduced the uptake and export to the shoot of both calcium and phosphate, while 0.1 m M Al increased the phosphorus level in the roots. To determine the impact of aluminium on the localization of calcium and phosphate, leakage of the elements from both intact plants and plants frozen prior to the leakage experiment was studied. The leakage of Ca²⁺ from intact plants was not affected by prior exposure to 0.1 m M Al. Freezing of the beech plants before the leakage experiment increased leakage of calcium slightly more from roots of control plants than for roots exposed to 0.1 m M Al, indicating that even low concentrations of alminium may impede the influx of calcium across the plasma membrane in the roots. The patterns of Ca²⁺ leakage from roots previously exposed to 1.0 m M Al indicated that very little Ca²⁺ was located extracellularly. The extracellular fraction of phosphate increased with increasing Al concentration in the nutrient solution. Low Al concentration (0.1 m M ) only reduced the intracellular phosphate concentration to a minor extent, while 1.0 m M Al profoundly decreased it. It is concluded that 0.1 m M AlCl₃ has a limited effect upon the localization of Ca²⁺ and phosphate in the roots. At higher levels of Al, 0.1–1.0 m M , there is a more dramatic change in nutrient localization in the free space and uptake over the plasma membrane.     

Mineral content and blood parameters of dying brown trout (Salmo trutta L.) exposed to acid and aluminum in soft water.

1. Whole body mineral content and blood parameters were monitored in dying brown trout exposed to acid (pH 4.5) and aluminium (12 mumol l-1) at low external calcium concentration (20 mumol l-1). 2. Fish surviving the treatment had elevated haematocrit, low plasma sodium levels, and low whole body sodium and potassium content. 3. Dying trout had haematocrit and plasma sodium levels similar to treatment survivors, but whole body mineral content was unaffected and moisture content increased. 4. Death was probably caused by redistribution of fluid from the extracellular compartment to the intracellular compartment.     

Plasma Renin Activity and Blood Pressure in 89 Patients Receiving Maintenance Haemodialysis Therapy

Blood pressure, plasma renin activity, plasma sodium concentration, plasma potassium concentration, dietary sodium intake, and duration of dialysis have been measured under standard conditions in 89 patients on maintenance haemodialysis. No significant relation was found between plasma renin activity and blood pressure. Statistically significant correlations were found between plasma renin activity and plasma sodium concentration and between plasma renin activity and dietary sodium intake.Only one patient was found to have uncontrollable hypertension associated with a markedly raised plasma renin activity. Reasons are given for not performing bilateral nephrectomy in this patient. We believe the low incidence of uncontrollable hypertension and hyperreninaemia in our patients to be due to their slow introduction to haemodialysis, thus preventing violent swings in body weight, blood pressure, and renin secretion.Although plasma renin activity did fall with duration of dialysis, all 15 patients who have been on maintenance dialysis for longer than five years have normal levels.     

Radioimmunoassay of atrial natriuretic peptide in human plasma: application to studies of volume and blood pressure homeostasis

Sensitive radioimmunoassay for determination of immunoreactive atrial natriuretic peptide (ANP) in human plasma was developed and employed for the study of plasma ANP concentrations in healthy controls under basal conditions (2.4 +/- 0.1 pmol/l) and during volume expansion by saline infusion (9.6 +/- 2.0 pmol/l and 14.2 +/- 1.8 pmol/l, respectively). Plasma renin activity and plasma aldosterone concentration exhibited opposite changes during saline infusion. In pathological states associated with extracellular fluid volume (ECFV) expansion, ANP concentration were significantly higher than in the controls (liver cirrhosis 8.6 +/- 0.9; congestive heart failure 33.1 +/- 4.8; chronic renal failure before haemodialysis 72.2 +/- 6.4 pmol/l). Further volume expansion in liver cirrhosis by saline infusion led to the further increase in ANP (13.3 +/- 1.3 and 16.1 +/- 1.5 pmol/l, respectively) and ECFV reduction by ultrafiltration during haemodialysis in chronic renal failure diminished but did not normalize plasma ANP (22.5 +/- 2.9 pmol/l). In patients with arterial hypertension the concentration of ANP exceeded the normal range by 62.5% and reached 8.0 +/- 0.5 pmol/l on the average. Our results support the suggestion that ANP is an important regulatory humoral mechanism participating in the regulation of sodium, volume and blood pressure homeostasis.     

Effects of ethanol, fructose, and ethanol plus fructose infusions on plasma glucose concentration and glucose turnover in monkeys (Macaca fascicularis) as measured by [6-3H]glucose

Six adult, female, cynomolgus monkeys were fasted for 64 hr and then continuously infused with [6-3H]glucose to determine the rates of glucose turnover and clearance while they were also being infused with ethanol (110 mumol/min/kg), 1,3-butanediol (110 mumol/min/kg), fructose (30 mumol/min/kg) or ethanol plus fructose (110 and 30 mumol/min/kg) respectively. Both ethanol and 1,3-butanediol infusions decreased the glucose turnover rate (the steady-state input-output rate from the plasma glucose pool) and the plasma glucose concentration by halving the glucose production rate. In contrast, fructose infusions increased the glucose turnover rate and glucose concentration by increasing the glucose production rate by 20%. The plasma clearance rate of glucose was lowest when the animals were infused with ethanol plus fructose; this suggests that acetate from ethanol oxidation may have a glucose-sparing effect if normoglycemia is maintained.     

Human plasma carboxyl esterase-catalyzed triolein hydrolysis. Existence of promoting factor in serum

The possibility that some factor in serum changes the substrate specificity of purified human plasma carboxyl esterase, which hydrolyzes the short chain fatty acid ester, tributyrin, was investigated. The purified carboxyl esterase from human plasma hydrolyzed 48 mmol of tributyrin/mg of protein/h, monoolein at 1560 mumol of released fatty acids/mg of protein/h, diolein at 133 mumol of released fatty acids/mg of protein/h, and triolein at less than 10 mumol of released fatty acids/mg of protein/h. When human serum was applied to phenyl-Sepharose, a triolein hydrolysis-promoting factor (THPF) for purified carboxyl esterase was bound to the gel and was eluted with water. This partially purified human serum THPF enhanced carboxyl esterase-catalyzed triolein hydrolysis about 30-fold, diolein hydrolysis 2-fold, and monoolein hydrolysis 1.5-fold. Hydrolysis of triolein in very low density lipoproteins (d less than 1.006) and intermediate lipoproteins (1.006 less than d less than 1.019) by carboxyl esterase was also enhanced by addition of THPF. THPF activity was reduced by treatment of delipidation, but resistant to trypsin treatment or heating at 50 degrees C. These results indicated that serum carboxyl esterase can hydrolyze the long chain fatty acid ester, triolein, in the presence of triolein hydrolysis-promoting factor in serum.     

Flame atomic emission spectrometric determination of aluminium in a bovine blood plasma matrix

A flame atomic emission spectrometric method, is described for the determination of aluminium in bovine blood plasma matrices. Plasma samples are wet-digested and solutions are aspirated into a conventional nitrous oxide-acetylene flame. Analyte emission is monitored at 396.15 nm with corrections for background emission being obtained from measurements several tenths nm on both sides of the aluminium line. The mean recovery of 0.3–5 μg/ml aluminium added to model solutions containing 500–5000 μg Na/ml, 50–1000 μg Ca/ml, 2000–5000 μg K/ml, or simulated plasma digests containing Na, K, and Ca was 100,6% (SD = 10.9, df = 60); the mean recovery of 0.3, 0.5, and 1.0 μg/ml aluminium added to blood plasma before digestion was 94.3% (SD = 9.8, df = 33) indicating no serious interferences. For standard solutions, the detection limit (signal: peak-to-peak noise = 1) was 0.02 μg/ml by flame emission, and 0.12 μg/ml by atomic absorption measurements with the same instrument. A sample taken through the analytical procedure, gave a detection limit of 0.05 μg/ml suggesting the submicrogram per milliliter region as the lower practical limit of the method.     

Catecholamine release and interrenal response of brown trout, Salmo trutta, exposed to aluminium in acidic water

Cannulated brown trout, Salmo trutta , were exposed for 36 h to synthetic water with a low calcium content of pH 5 and similar synthetic water dosed with aluminium to raise the filterable A1 from 5 to 290 μg 1⁻¹ over the 36-h period. There were no significant disturbances of plasma concentrations of glucose, cortisol or catecholamine (adrenaline and noradrenaline) in fish held in water of pH 5. The addition of aluminium to this acidic synthetic water resulted in a generalized endocrine stress response with a four-fold increase in plasma glucose concentration after 18 h and a significant increase in plasma cortisol concentration from 24 h onwards when filterable A1 exceeded 200 μg 1⁻¹. Plasma catecholamine concentration indicated an adrenergic stress response in aluminium-exposed brown trout. A transient doubling in noradrenaline after 6 h in A1 was followed by a larger increase in both plasma adrenaline and noradrenaline concentrations in fish surviving the 36-h exposure to A1.