Hypokalaemia following nebulized salbutamol in children with acute attack of bronchial asthma

OBJECTIVE: To determine whether use of nebulized salbutamol therapy for treatment of an acute attack of asthma in children is associated with hypokalaemia and if so what is its frequency, severity and effect on recovery. METHODOLOGY: Forty-six children, aged 10 months to 12 years (mean 7.9 +/- 1.5 years) with acute attack of bronchial asthma, treated initially with three doses of nebulized salbutamol 0.15-0.3 mg/kg, every 30 min participated in the study. Blood for serum potassium was obtained at the beginning and after three doses of nebulized salbutamol therapy, before administering other drugs. RESULTS: The mean +/- SD serum potassium level decreased marginally from 3.9 +/- 0.5 mEq/L to 3.7 +/- 0.5 mEq/L (P < 0.05). A decrease in serum potassium concentration was noted in 26 (56.5%) and hypokalaemia (serum potassium < 3.5 mg/L) in 17 (39%) patients. It was more frequent in patients who had received oral salbutamol for the preceding 7 days. The average time taken for recovery was longer in patients who had hypokalaemia than those who had normal serum potassium concentration (8.6 +/- 2.7 h vs 6.5 +/- 2.7 h; P < 0.005). CONCLUSIONS: Hypokalaemia may occur in about one-third of patients treated with three doses of nebulized salbutamol therapy, especially those on prior oral salbutamol therapy. The monitoring of serum potassium concentration may be warranted in such patients.     

Treatment of hyperkalaemia by altering the transcellular gradient in patients with renal failure: effect of various therapeutic approaches

Ten patients with acute and 60 with chronic renal failure (both groups having hyperkalaemia), were managed at Kenyatta National Hospital in the medical wards and Renal Unit between August, 1995 and January, 1996. They were divided into seven different treatment groups, each consisting of ten patients. Treatment A glucose 25g i.v. with insulin 10 units i.v., treatment B 50 mmol of 8.4% sodium bicarbonate infusion, treatment C 0.5mg of salbutamol i.v. in 50mls 5% dextrose, treatment D was a combination of treatments A and B, treatment E was a combination of treatment B and C, treatment F was a combination of treatments A and C while treatment G was a combination of treatments A and B and C. Serum potassium was measured, 30 minutes, 1 hour, 2 hours, 4 hours and 8 hours after treatment. Plasma glucose concentration was measured before treatment was given and 1 hour after in all patients. Electrocardiography was done before treatment on all patients and repeated 30 minutes and 1 hour after treatment for the patients with hyperkalaemic changes on the initial recording. All treatment modalities had satisfactory potassium lowering effects. Of the single therapeutic approaches, treatment A and C were equieffective, but better than treatment B (P < 0.001). Amongst the two regimen combinations, treatment D and F were more efficacious than treatment E and all the single therapeutic approaches (P < 0.001). Treatment G was the most efficacious in lowering serum potassium in this study. All treatment modalities had maximum serum potassium lowering effect at 1-2 hours. A fall in plasma glucose concentration was a notable feature of treatments A and D, but significant hypoglycaemia occurred in 20% of patients receiving treatment A and in none on treatment D. The ECG changes of hyperkalaemia did not correlate with serum potassium levels. The normalisation of hyperkalaemic ECG alteration occurred within the first 30 minutes after treatment. In conclusion, combination therapies for hyperkalaemia appear to be more efficacious than single therapeutic approaches. Inclusion of salbutamol seems to protect against insulin induced hypoglycaemia. The maximum potassium lowering effect is observed 1-2 hours of administration of either agents. The potassium reducing effect remains significant compared to baseline values even after 8 hours. If dialysis cannot be instituted early enough it seems reasonable to repeat treatment every 4-6 hours to sustain the effect. Repeated administration of glucose with insulin may not be safe because of the hypoglycaemic effect. Other single and combination therapies can theoretically be repeated regularly until dialysis is initiated although this requires further clinical evaluation.     

Postoperative arrhythmias and myocardial electrolytes in patients undergoing coronary artery bypass grafting

Electrolyte changes in right atrial and skeletal muscle pre- intra- and postoperatively, and their relationship to the development of postoperative atrial fibrillation or flutter were evaluated in 31 patients with coronary artery bypass grafting (CABG). Such postoperative arrhythmias occurred in 14 patients (45%). Before CABG the skeletal muscle potassium concentration was lower in these patients than in the others: median 261.4 (range 148.2-329.5) vs 298.6 (167.1-416.4) mumol/g dry weight, p = 0.017. The right atrial potassium concentration was normal, but sodium levels were higher in the patients with, than in those without postoperative arrhythmias: median 340.3 (263.7-454.9) vs 296.3 (203.9-355.0) mumol/g dry weight, p = 0.008, indicating disturbed transmembrane electrolyte transfer. During CABG the potassium levels fell and sodium increased in both right atrium and skeletal muscle, and on postoperative day 2 the potassium content in skeletal muscle was not yet restored. Magnesium levels showed no changes in right atrium or skeletal muscle, but serum magnesium declined postoperatively. As the observed electrolyte derangements may be important in the development of postoperative arrhythmias, concomitant potassium and magnesium supplement postoperatively may be beneficial in restoring cellular potassium concentration.     

The effect of prophylactic use of furosemide on renal function during open heart surgery

Forty-five patients who underwent open heart surgery were divided into a short-perfusion group (SPG, 21 patients) with a perfusion time shorter than 60 minutes and a long-perfusion group (LPG, 24 patients) with a perfusion time longer than 60 minutes. Nine patients in the SPG and 13 in the LPG received furosemide prophylactically prior to the perfusion. The furosemide dose was 20-60 mg. During the perfusion and postoperatively all patients were given furosemide when necessary, i.e. when the volume for diuresis per hour declined below 40 ml/h. The patients who received prophylactic furosemide in the LPG subsequently had clearly less need for furosemide (3.9 mg/h) than the control subjects (7.9 mg/h/3 day). The patients with furosemide prophylaxis in the LPG had significantly ( less than 0.05) higher creatinine clearance and lower serum creatinine values during the postoperative night period and on the 3rd day. In perfusions lasting less than 60 minutes the patients with furosemide prophylaxis had significantly higher urine flow (p less than 0.001), sodium excretion (p less than 0.001) and potassium excretio-n (p less than 0.01) during bypass surgery and postoperatively compared with that of controls. According to our findings, the prophylactic use of furosemide had a beneficial effect on glomerular filtration rate (endogenous creatinine clearance) and postoperative serum creatinine level in LPG. In perfusion shorter than 60 minutes furosemide prophylaxis may be harmful owing to the increased excretion of water, sodium and potassium.     

Outcomes after cervical cold knife conization with complete and incomplete excision of abnormal epithelium: a review of 699 cases

The serum samples from 29 patients with Parkinson's disease were analysed for the levels of the autoantibodies (a-AB) and antiidiotype antibodies (AIAB) to the proteins of nervous system S-100, GFAP, NKP and MP-65. High levels of a-AB or AIAB to at least 3 proteins were seen in patients with severe course of the disease. No significant changes of these levels were observed in patients with light course of the disease. The plasmapheresis was carried out to some patients with severe course of the disease. After this procedure the decrease of neurological deficit from number 21 +/- 2 to 8 +/- 1 on Webster's scale and decrease of a-AB and AIAB levels to normal values (in some cases it became lower than normal values) were observed. It can be concluded that the levels of the a-AB to the nervous tissue proteins correlate with clinical condition of the patient.     

Serum Amylase elevation following hepatic resection in patients with chronic liver disease

BACKGROUND: Factors liable to cause hyperamylasemia after hepatectomy were studied retrospectively in 140 patient with chronic liver disease. METHODS: The pringle maneuver was performed in 113 patients (Pringle group), the hemihepatic vascular occlusion technique in 21 (hemihepatic group), and no vascular occlusion in 6 (no-occlusion group). RESULTS: In the Pringle group, postoperative serum amylase levels were elevated significantly in comparison with the preoperative levels, but were not elevated in hemihepatic and no-occlusions groups. In the Pringle group, there were 4 patients whose postoperative serum amylase levels exceeded 3.5 times the upper limit of the normal range together with serum pancreatic isoamylase or lipase elevation or both. When compared with the other 109 patients, these 4 patients had a significantly longer vascular occlusion time (51 +/-3 minutes versus 94 +/- 8 minutes P<0.005). One of them developed pancreatitis and died from hepatic failure. CONCLUSION: Prolongation of portal congestion carries a potential risk of serum amylase elevation and pancreatitis after hepatectomy in patients with underlying liver disease.     

Trypanosoma cruzi meningoencephalitis in AIDS mimicking cerebral metastases: case report

BACKGROUND: It has been suggested that citrate salts might enhance aluminum (Al) absorption from a normal diet, posing a threat of Al toxicity even in subjects with normal renal function. We have recently reported that in normal subjects and patients with moderate renal failure, short-term treatment with tricalcium dicitrate (Ca3Cit2) does not significantly change urinary and serum Al levels. However, we have not assessed total body Al stores in patients on long-term citrate treatment. OBJECTIVE: The objective of this study was to ascertain body content of Al non-invasively using the increment in serum and urinary Al following the intravenous administration of deferoxamine (DFO) in patients with kidney stones and osteoporotic women undergoing long-term treatment with potassium citrate (K3Cit) or Ca3Cit2, respectively. METHODS: Ten patients with calcium nephrolithiasis and five with osteoporosis who were maintained on potassium citrate (40 mEq/day or more) or calcium citrate 800 mg calcium/day (40 mEq citrate) for 2 to 8 years, respectively, and 16 normal volunteers without a history of regular aluminum-containing antacid use participated in the study. All participants completed the 8 days of study, during which they were maintained on their regular home diet. Urinary Al excretion was measured during a two-day baseline before (Days 5, 6) and for 1 day (Day 7) immediately following a single intravenous dose of DFO (40 mg/kg). Blood for Al was obtained before DFO administration, and at 2, 5 and 24 hours following the start of the infusion. RESULTS: The median 24-hour urinary Al excretion (microgram/day) at baseline versus post-DFO value was 15.9 vs. 44.4 in the normal subjects and 13.3 vs. 35.7 in the patients. These values were all within normal limits and did not change significantly following DFO infusion (p = 0.003 and p = 0.0001, respectively). The median change of 17.1 micrograms/day in urinary Al in the normal subjects was not significantly different from the 18.7 micrograms/day change measured in the patient group (p = 0.30). Similarly, no change in the mean serum Al was detected at any time following the DFO infusion, either in the patient or control group (patients 4.1 to 4.3 ng/ml, controls 7.4 to 4.6 ng/ml). CONCLUSION: The results suggest that abnormal total body retention of Al does not occur during long-term citrate treatment in patients with functioning kidneys.     

Free-water clearance and the early recognition of acute renal insufficiency after cardiopulmonary bypass

The predictive value of free-water clearance measurements for the early recognition of acute renal insufficiency was evaluated in 59 patients immediately following cardiopulmonary bypass. Blood urea nitrogen and serum creatinine measurements were taken before and after operation. Intraoperatively, immediately after completion of bypass, urine and serum samples were obtained for osmolality. Duration of bypass, urine output, degree of hemolysis, and quality of perfusion were recorded. Fifty-four patients developed no signs of renal insufficiency following bypass, and all had free-water clearance values equal to or less than -20 ml per hour. Five patients who had free-water clearance values equal to greater than -8 ml per hour developed manifestations of an acute renal insufficiency state. There were no false-negative or false-positive determinations. Consequently, free-water clearance measurements appear to be a reliable indicator of those patients who will develop renal insufficiency following cardiopulmonary bypass. Early recognition provides an opportunity immediately after operation for initiating treatment consisting of administration of diuretics, potassium restriction, and oliguric fluid regimens.     

Hyperkalemia in hospitalized patients treated with trimethoprim-sulfamethoxazole

OBJECTIVE: To determine the effect of standard-dose trimethoprim-sulfamethoxazole on serum potassium concentration in hospitalized patients. DESIGN: Prospective chart review. SETTING: Community-based teaching hospital. PATIENTS: 105 patients with various infections were hospitalized and treated. Eighty patients treated with standard-dose trimethoprim-sulfamethoxazole (trimethoprim, < or = 320 mg/d; sulfamethoxazole, < or = 1600 mg/d) composed the treatment group; 25 patients treated with other antibiotic agents served as the control group. MEASUREMENTS: Serum sodium, potassium, and chloride concentrations; serum carbon dioxide content; anion gap; blood urea nitrogen level; and serum creatinine level. RESULTS: The serum potassium concentration in the treatment group (mean +/- SD) was 3.89 +/- 0.46 mmol/L (95% CI, 3.79 to 3.99 mmol/L), and it increased by 1.21 mmol/L (CI, 1.09 to 1.32 mmol/L) 4.6 +/- 2.2 days after trimethoprim-sulfamethoxazole therapy was initiated. Blood urea nitrogen levels increased from 7.92 +/- 5.7 mmol/L (CI, 6.67 to 9.16 mmol/L) to 9.2 +/- 5.8 mmol/L (CI, 7.9 to 10.5 mmol/L), and serum creatinine levels increased from 102.5 +/- 49.5 mumol/L (CI, 91.4 to 113.6 mumol/L) to 126.1 +/- 70.7 mumol/L (CI, 110.3 to 141.9 mumol/L). Patients with a serum creatinine level of 106 mumol/L (1.2 mg/dL) or more developed a higher peak potassium concentration (5.37 +/- 0.59 mmol/L [CI, 5.15 to 5.59 mmol/L]) than patients with a serum creatinine level of less than 106 mumol/L (4.95 +/- 0.48 mmol/L [CI, 4.80 to 5.08 mmol/L]). Patients with diabetes had a slightly higher peak potassium concentration (5.14 +/- 0.45 mmol/L [CI, 4.93 to 5.39 mmol/L]) than did patients without diabetes (5.08 +/- 0.59 mmol/L [CI, 4.93 to 5.23 mmol/L]), but the difference was not statistically significant. The serum potassium concentration in the control group was 4.33 +/- 0.45 mmol/L (CI, 4.15 to 4.51 mmol/L), and it decreased nonsignificantly over 5 days of therapy. CONCLUSIONS: Standard-dose trimethoprim-sulfamethoxazole therapy used to treat various infections leads to an increase in serum potassium concentration. A peak serum potassium concentration greater than 5.0 mmol/L developed in 62.5% of patients; severe hyperkalemia (peak serum potassium concentration > or = 5.5 mmol/L) occurred in 21.2% of patients. Patients treated with standard-dose trimethoprim-sulfamethoxazole should be monitored closely for the development of hyperkalemia, especially if they have concurrent renal insufficiency (serum creatinine level > or = 106 mumol/L).     

Endogenous erythropoietin in patients on regular dialysis therapy

In a group of 66 patients with chronic renal failure having regular dialyzation treatment the serum concentration of endogenous erythropoietin (EPO), haemoglobin levels (Hb), haematocrit (Ht) and serum creatinine (Cr) were assessed. The examined subjects were never treated with recombinant erythropoietin and deficiency of iron, folic acid and vitamin B12 was ruled out. Endogenous EPO was assessed by the authors own RIA method, normal values being 24-42 mU/ml. The mean EPO concentration in the whole group of patients was 37.4 +/- 15.3 mU/ml, whereby 12 patients had an EPO serum concentration higher than the upper range of normal values. Between EPO concentrations and Hb values a certain positive correlation was found (r = 0.42). A similar relationship was revealed also between EPO concentrations and Ht values (r = 0.41). Patients with EPO values higher than 42 mU/ml had, as compared with the other patients, significantly higher values of erythrocytes (p .001). Statistical analysis did not reveal any relationship between EPO and Cr concentrations (r = -0.04). A low negative correlation was found between Cr and Hb values (r = -0.31) and between Cr and Ht values (r = -0.25). In the discussion the authors analyze the contemporary state of the problem of anaemia in chronic renal failure. Based on hitherto assembled knowledge they formulated the hypothesis ascribing considerable pathogenetic importance in the development of anemia to reduced sensitivity of bone marrow to EPO, probably as a result of retention of uraemic toxins and inhibitors of erythropoiesis. Inadequate EPO formation could be only a factor which makes it impossible for the developing anaemia to compensate and is due to an animpaired feedback at the level of recognition of the hypoxic signal.     

Selenium deficiency associated with cardiac dysfunction in three patients with chronic respiratory failure

We encountered three patients with chronic respiratory failure who had heart failure of cardiac arrhythmias and low levels of serum selenium. All three had tracheostomies and had received long-term parenteral nutrition that had not included selenium. All three also had refractory cardiac dysfunction, which was manifested in edema, heart failure, and various tachycardias. We suspected that selenium deficiency had caused their cardiac dysfunction. Serum selenium concentrations were found to be much lower than normal in all three, so 100 micrograms/day of selenium was administered in addition to their tube feedings. Cardiac function improved after replacement of selenium. These cases show the need for preventing selenium deficiency in patients with chronic respiratory failure during long-term administration of parenteral nutrition.     

Mechanism of increased serum cytokeratin 19 fragment levels in patients with diabetic nephropathy as a model of chronic renal failure

We examined serum and urinary cytokeratin 19 fragment (CYFRA 21-1) levels in patients with diabetic nephropathy as a model of chronic renal failure, to investigate the mechanism of increased serum CYFRA 21-1 levels in chronic renal failure. Serum and urinary CYFRA 21-1 levels in non-insulin-dependent diabetes mellitus (NIDDM) patients with abnormal urinary immunoglobulin G (IgG) levels (>1.1 mg/g x Cr, n=126) were higher than those with normal urinary IgG levels. In NIDDM patients with normal urinary IgG levels (n=81); the urinary albumin or transferrin levels were not related to serum or urinary CYFRA 21-1 levels. We speculate that the increased serum CYFRA 21-1 levels contribute to metabolic abnormality in the kidney itself rather than the decreased urinary excretion per se, and that increased urinary CYFRA 21-1 levels are found in advanced cases of diabetic nephropathy with destruction of the size barrier.     

Does precurarization prevent the increase of serum potassium after administration of succinylcholine in risk patients? - a case report- (author's transl)

There are different opinions about the efficiency of preventing the succinylcholine-induced increase of serum potassium by precurarization. The following case report demonstrates that this method is not practicable in risk patients. A case of severe cerebral trauma is reported, in whom after precurarization with 2,0 mg diallyl-nortoxiferine and with 1.5 mg pancuronium, too, there was an increase of a normal serum potassium level up to 9.35 respectively 9.20 mEq/l about 1-2 minutes after injection of succinylcholine. 20 minutes after the injection serum potassium decreased to a normal level again. Only a short lasting bradycardia was noticed during the hyperkaliaemic period. Similar results reported in the anaesthesiologic literature are discussed.     

Assessment of nutritional status in CAPD patients: serum albumin is not a useful measure

INTRODUCTION: In CAPD patients serum albumin is frequently used as an index of nutritional status, although it is recognized that hypoalbuminaemia may be caused by many factors. We have further examined the relationship between serum albumin and nutrition. METHODS: Nutritional status was assessed by biochemistry, anthropometry, mid-arm muscle circumference, muscle strength (hand grip and back), and lean body mass (from anthropometry, creatinine kinetics and bioimpedance) in a group of 76 stable CAPD patients. Correlations between biochemical and nutritional parameters were sought and data were compared between patient groups defined by serum albumin (> or = 37 vs < 37 g/l on two occasions 2 months apart) and separately according to subjective global assessment score (normal nutrition, A vs mild to moderate, B, and severe, C, malnutrition). RESULTS: In patients with a low SGA score, actual body weight, body mass index, mid-arm muscle circumference, lean body mass, subscapular skinfold thickness, hand grip strength (males and females) and iliac and triceps skinfold thicknesses and back strength (females only) were all significantly less than in patients with a normal SGA score. In contrast, none of these variables differed in either gender when patients were compared according to serum albumin. Serum albumin was correlated with serum creatinine (r = 0.45, P = 0.01), daily urine protein excretion (r = -0.42, P = 0.02) and uncorrected weekly creatinine clearance (r = -0.39) in females, but not with any index of body composition in either gender. CONCLUSION: Whilst SGA identified a patient group with significantly abnormal body mass, muscle mass and muscle strength, serum albumin did not. Serum albumin is not a useful marker of malnutrition in stable patients on CAPD.     

Essential fatty acid deficiency and home total parenteral nutrition patients

The requirements for essential fatty acids in patients on home parenteral nutrition are not well described. We therefore studied the needs of 12 patients receiving parenteral nutrition for at least 4 mo (range: 4 mo-17.3 yr; mean 7.0 +/- 5.2 yr). Prior to the study, each patient had been receiving intravenous lipids either weekly or biweekly and had a triene to tetraene ratio (TTR) on plasma phospholipids performed at least annually. A TTR > or = 0.2 was considered diagnostic for essential fatty acid deficiency (EFAD). The purpose of this study was to determine the required intravenous lipid supplementation in patients on home total parenteral nutrition (HTPN). Patients with an initial TTR of < 0.2 had their intravenous lipid stopped and changes in their serum phospholipid fatty acids were followed every 3-4 wk. Nine of 12 patients had TTRs > 0.2 at some point in the study. Phase I consisted of patients who at initiation of the study had normal TTRs and were taken off lipid supplementation until their TTR became abnormal. Phases II, III, IV, and V consisted of lipid delivered in total nutrient admixtures in biweekly doses of 0.6, 1.2, 1.8, and 2.4 g of fat/kg bodyweight, respectively. Eight patients normalized their TTRs on the biweekly lipid regimens; one patient expired before his ratio normalized; and three patients could not be made deficient in essential fatty acids after 26 or more wk of fat-free parenteral nutrition. Most patients required 1.2 to 2.4 g of lipid/kg bodyweight/biweekly to correct serologic EFAD. The clinical background, as well as the length of small bowel remaining, did not seem to identify those patients who required lipid supplementation nor the final dose of lipid needed to normalize their TTRs.     

Recovery of free ADP, Pi, and free energy of ATP hydrolysis in human skeletal muscle

BACKGROUND: Recent studies have demonstrated that a high concentration of phosphate directly stimulates parathyroid hormone (PTH) secretion. High serum levels of phosphate are usually observed in patients with end-stage renal disease. The aim of the present study was to evaluate whether serum phosphate concentration had an acute effect on PTH secretion in hemodialysis patients. The levels of serum phosphate were manipulated during the hemodialysis session by using a phosphate free dialysate or a dialysate with a high content of phosphate. METHODS: Ten stable hemodialysis patients with PTH values above 300 pg/ml were included in the study. A PTH-calcium curve was obtained during both high phosphate and phosphate free hemodialysis. RESULTS: The serum phosphate concentration remained high (2.17 +/- 0.18 mM) throughout the high phosphate hemodialysis and decreased progressively to normal levels (1.02 +/- 0.06 mM) during the phosphate free hemodialysis. The serum PTH levels at maximal inhibition by hypercalcemia (minimal PTH) were greater during the high phosphate than the phosphate free hemodialysis (413 +/- 79 vs. 318 +/- 76 pg/ml, P < 0.003). In all patients the values of minimum PTH were greater during the high phosphorus than the phosphorus free hemodialysis. The values of maximally stimulated PTH during hypocalcemia and the set point of the PTH-calcium curve were similar during the high phosphate and the phosphate free hemodialysis. CONCLUSION: The maintenance of high serum phosphorus levels during hemodialysis prevented, in part, the inhibition of PTH secretion by calcium, which strongly suggests that in hemodialysis patients high serum phosphate contributes directly to the elevation of PTH levels despite normal or high serum calcium concentration.     

Serum magnesium, serum potassium and arrhythmia profile in patients with acute myocardial infarct

In 176 patients with acute myocardial infarction (AMI) serum magnesium concentration (MGK) and serum potassium concentration (KK) were analysed during the first 48 hours after AMI. The patients rhythm was continuously recorded. In a subgroup of 70 patients a signal averaging-ECG was performed. 4.5% of the patients had a low, 55.7% a normal and 39.8% a high MGK. 14.8% of the patients had a low, 80.1% a normal and 5.1% a high KK. Ventricular arrhythmias > or = Lown IV b were found in 25% of the patients with low MGK, in 38.8% with normal and in 52.9% with high MGK. 50% of the patients with low, 62.2% with normal and 61.3% with high MGK had late potentials. There was no relation between hypomagnesemia and ventricular arrhythmias as between hypomagnesemia and late potentials. Thus, hypomagnesemia in AMI patients is rare and does not correlate with ventricular arrhythmia or delayed ventricular potentials.     

Erythrocyte sodium and potassium in patients with hypokalaemia

1. The erythrocyte content of sodium and of potassium were measured in 231 unselected patients with hypokalaemia, and together with net ouabain-sensitive sodium efflux in patients with severe hypokalaemia, before (20 patients) and during potassium repletion (14 patients). 2. The erythrocytes of the patients with hypokalaemia compared with control subjects had on average an increase in sodium content, a decrease in potassium content and a reduction in the rate constant of ouabain-sensitive sodium efflux. All three changes had a similar curvilinear relation to the concentration of potassium in plasma with relatively little change in the measured variable unless the plasma potassium was very low. 3. There was a similar curvilinear relation between the final sodium and potassium content of normal erythrocytes and the potassium concentration of the medium in which they were incubated for 48 h in vitro. 4. These results suggest that the changes in the sodium and potassium content of erythrocytes in hypokalaemia are due to a direct inhibiting effect of the hypokalaemia on the activity of the sodium pump. 5. In many patients with hypokalaemia of moderate degree the increase in erythrocyte sodium content was less than expected from the effect in vitro of a low extracellular potassium concentration. This finding suggests that a compensatory change, presumably an increase in the number of sodium pumps, is a common event even in moderate hypokalaemia.     

Magnetic resonance imaging assessment of disc degeneration 10 years after anterior lumbar interbody fusion

OBJECTIVE: Insulin-like growth factor (IGF-I) action is influenced by circulating as well as tissue levels of its binding proteins. Because serum IGF binding protein-1 (IGFBP-1) levels have been found to be decreased in patients with polycystic ovary syndrome (PCOS), we tested the hypothesis that regulation of IGFBP-1 secretion may be different in patients with PCOS compared with normal women. METHODS: We studied 15 normal ovulatory women and 15 women with PCOS of similar age (21 +/- 1 and 22 +/- 1 years, respectively). All subjects were studied after an overnight fast between days 5-8 after spontaneous or progestin-induced menses. Perturbations included the administration of insulin intravenously, maintenance of a euglycemic clamp, and, in a subsequent cycle, the administration of a long-acting somatostatin analogue (octreotide, 100 micrograms) given subcutaneously. Blood samples were collected before treatment, every 15 minutes for 6 hours after insulin, and every 30 minutes for 3 hours after octreotide administration. Serum levels of IGF-I, IGFBP-1, IGFBP-3, and insulin were measured by specific immunoassays. RESULTS: Compared with the controls, patients with PCOS had significantly higher insulin levels, similar IGF-I and IGFBP-3 levels, and significantly lower IGFBP-1. Insulin did not change serum IGF-I levels in either group, although a significant decrease in IGFBP-1 levels occurred in normal women but not in patients with PCOS. Octreotide treatment also did not change serum IGF-I levels in either group, but serum insulin levels decreased significantly and IGFBP-1 levels increased significantly in both groups; this response was significantly greater in controls. CONCLUSIONS: Our data are compatible with the notion that regulation of IGFBP-1 is altered in women with PCOS and that several factors may be involved.     

The effect of long-term thyroxine on bone mineral density and serum cholesterol

The effect of thyrotrophin suppression on bone mineral density (BMD) and serum cholesterol concentration was assessed in 31 treated hypothyroid women. Measurements of the BMD of the lumbar spine and femoral neck were repeated in seven of those with the lowest value after an average period of 22.7 months. Final cholesterol concentrations were compared with values before thyroxine was started. The dose of thyroxine was based on clinical assessment, serum triiodothyronine concentrations kept within the normal range, and thyrotrophin values within the normal range or suppressed. The patients had taken thyroxine replacement for a mean of 12.7 years. Two-thirds (21 subjects) had suppressed thyrotrophin concentrations, and it was normal in one-third (10). Fifteen subjects had a past history of thyrotoxicosis. BMD and cholesterol concentrations were compared between those with suppressed and normal thyrotrophin concentrations and between those with and without a past history of thyrotoxicosis. No patient had a pathological fracture. One had a Z value for the femoral neck of -1.6, denoting early but definite osteoporosis, and five had borderline osteoporosis with Z values for one or other site between -1.1 and -1.5. None of the seven with the lowest BMDs had any significant change when measurements were repeated. The difference in Z values between subjects with suppressed and normal thyrotrophin concentrations was not significant for either the lumbar spine (p = 0.68) or the femoral neck (p = 0.28). A past history of thyrotoxicosis had a greater effect on BMD for both sites than thyrotrophin suppression, but again the difference between those with and without a past history of thyrotoxicosis was significant neither for the lumbar spine (p = 0.18) nor for the femoral neck (p = 0.34). The combination of thyrotrophin suppression and a past history of thyrotoxicosis also failed significantly to reduce the BMD of the lumbar spine (p = 0.38) or femoral neck (p = 0.30) in comparison with those who had neither thyrotrophin suppression nor a past history of thyrotoxicosis. The mean fall in serum cholesterol concentration was 2.1 mmol/l (SD 1.78) (p = 0.001) in those with a suppressed thyrotrophin concentration taking a mean daily dose of thyroxine of 171 micrograms (SD: 34.7), compared with a fall of 0.89 mmol/l (SD: 1.04) (p = 0.065) in those whose thyrotrophin concentration was not suppressed on a mean daily thyroxine dose of 140 micrograms (SD: 50). No patient had atrial fibrillation or cardiographic evidence of coronary artery disease (CAD). The serum cholesterol concentration should play at least as important a part in influencing the dose of thyroxine as a fear of osteoporosis. Fractures are not a feature in the natural history of treated hypothyroidism, whereas CAD is a common cause of death in these patients.