Plasma spermine concentrations of patients with benign and malignant tumours of the breast or prostate.

A radioimmunoassay has been developed for the measurement of plasma spermine concentrations. The sensitivity of the method is 1 pmol spermine/100 microliters plasma and the crossreactivity was 12% with spermidine and 0.18% with putrescine. Plasma spermine levels of patients with benign and malignant tumours of the prostate or breast were measured using this technique. Concentrations were only occasionally elevated in patients with prostatic tumours compared to normal individuals and there was no difference between those men with benign (mean concn. 0.21 +/- 0.14 nmol/ml plasma) or malignant (mean concn. 0.21 +/- 0.11 nmol/ml plasma) tumours. Only 17% of the patients with breast carcinoma had elevated levels of spermine, although there was a significant difference in the concentrations of the breast cancer group of patients compared to normals. No correlation was found between elevated plasma spermine concentrations and tumour grade or presence or spread of metastases in those patients.     

Elevated plasma noradrenaline concentrations in patients with low-output cardiac failure: dependence on increased noradrenaline secretion rates

1. Plasma noradrenaline concentrations are elevated in patients with congestive heart failure; however, the pathogenesis of these elevated noradrenaline levels is controversial. 2. Possible mechanisms for elevated noradrenaline concentrations in patients with congestive heart failure include increased noradrenaline secretion, decreased clearance of noradrenaline, and a combination of increased secretion and decreased clearance. 3. In the present study, plasma noradrenaline clearance and apparent secretion rates were determined using a whole-body steady-state radionuclide tracer method in six otherwise healthy patients with moderate degrees of low-output cardiac failure and in six normal control subjects. 4. The venous plasma noradrenaline level was elevated in the patients with congestive heart failure as compared with the control subjects (4.18 +/- 1.34 versus 1.54 +/- 0.16 nmol/l, P less than 0.05). There was no stimulation of the adrenal medulla as evident by normal plasma adrenaline levels in both groups (0.19 +/- 0.04 versus 0.18 +/- 0.02 nmol/l, not significant). The apparent secretion rate of noradrenaline was elevated in the patients with congestive heart failure (4.75 +/- 1.95 versus 1.78 +/- 0.18 nmol min-1 m-2, P less than 0.05), whereas the clearance rate of noradrenaline was similar in the two groups (1.26 +/- 0.27 versus 1.16 +/- 0.02 l min-1 m-2, not significant). 5. We conclude that the high peripheral venous plasma noradrenaline concentrations in patients with mildly decompensated low-output cardiac failure are initially due to increased secretion, rather than to decreased metabolic clearance, perhaps in response to diminished effective arterial blood volume.     

The content of unbound polyamines in blood plasma and leukocytes of patients with polycythemia vera.

In the blood plasma and isolated leukocytes of 11 patients with polycythemia vera and 3 healthy subjects, the polyamines putrescine, spermidine and spermine were determined. The average values in the leukocytes of the healthy volunteers were found to be 1.8 +/- 1.4 nmol putrescine/10(8) cells, 3.0 +/- 0.9 nmol spermidine/10(8) cells and 12.9 +/- 3.8 nmol spermine/10(8) cells. In the plasma of healthy persons the amounts of the polyamines were below the sensitivity level of the method employed. In 4 patients with polycythemia vera no polyamines were detected. In contrast, in 7 cases 0.1 to 3 nmol polyamines/ml were found. The level of polyamines in the leukocytes of 6 of these patients was decreased and in one patient corresponded to the values found in the normal range (17.7 +/- 6.0 nmol polyamines/10(8) cells). Continued blood-letting therapy on 3 patients led to values approaching the concentrations found in normal subjects in both blood plasma and leukocytes. A decreased amount of these diamines in the leukocytes of the patients was seen to correlate with an elevated concentration in the plasma.     

Plasma and muscle free carnitine deficiency due to renal Fanconi syndrome.

Plasma and urine free and acyl carnitine were measured in 19 children with nephropathic cystinosis and renal Fanconi syndrome. Each patient exhibited a deficiency of plasma free carnitine (mean 11.7 +/- 4.0 [SD] nmol/ml) compared with normal control values (42.0 +/- 9.0 nmol/ml) (P less than 0.001). Mean plasma acyl carnitine in the cystinotic subjects was normal. Four subjects with Fanconi syndrome but not cystinosis displayed the same abnormal pattern of plasma carnitine levels; controls with acidosis or a lysosomal storage disorder (Fabry disease), but not Fanconi syndrome, had entirely normal plasma carnitine levels. Two postrenal transplant subjects with cystinosis but without Fanconi syndrome also had normal plasma carnitine levels. Absolute amounts of urinary free carnitine were elevated in cystinotic individuals with Fanconi syndrome. In all 21 subjects with several different etiologies for the Fanconi syndrome, the mean fractional excretion of free carnitine (33%) as well as acyl carnitine (26%) greatly exceeded normal values (3 and 5%, respectively). Total free carnitine excretion in Fanconi syndrome patients correlated with total amino acid excretion (r = 0.76). Two cystinotic patients fasted for 24 h and one idiopathic Fanconi syndrome patient fasted for 5 h showed normal increases in plasma beta-hydroxybutyrate and acetoacetate, which suggested that hepatic fatty acid oxidation was intact despite very low plasma free carnitine levels. Muscle biopsies from two cystinotic subjects with Fanconi syndrome and plasma carnitine deficiency had 8.5 and 13.1 nmol free carnitine per milligram of noncollagen protein, respectively (normal controls, 22.3 and 17.1); total carnitines were 11.8 and 13.3 nmol/mg noncollagen protein (controls 33.5, 20.0). One biopsy revealed a mild increase in lipid droplets. The other showed mild myopathic features with variation in muscle fiber size, small vacuoles, and an increase in lipid droplets. In renal Fanconi syndrome, failure to reabsorb free and acyl carnitine results in a secondary plasma and muscle free carnitine deficiency.     

Enolase isoenzymes as tumour markers

alpha- and gamma-enolase isoenzyme substance concentrations were measured in serum and plasma from healthy subjects and from 174 patients with different solid tumours. While alpha-enolase was found to be increased in the plasma of patients with tumours of quite different origin, gamma-enolase apparently reflected malignancies of the neuroendocrine system. Before the beginning of the cytotoxic therapy gamma-enolase was increased above the upper limit of the reference range (10 micrograms/l) in 27/27 patients (100%) suffering from small cell lung cancer. Most patients with squamous cell carcinoma of the lung or with prostatic cancer exhibited normal gamma-enolase, while both tumour types produced high plasma substance concentrations of the alpha-isoenzymes of enolase.     

Plasma concentrations and comparisons of brain natriuretic peptide and atrial natriuretic peptide in normal subjects, cardiac transplant recipients and patients with dialysis-independent or dialysis-dependent chronic renal failure.

1. We have developed a radioimmunoassay for the measurement of immunoreactive brain natriuretic peptide (1-32) in human plasma. Simultaneous measurements of atrial natriuretic peptide have also been carried out to allow for direct comparison between circulating brain natriuretic peptide and atrial natriuretic peptide. Plasma levels of immunoreactive brain natriuretic peptide (means +/- SEM) were 1.1 +/- 0.1 pmol/l in 36 normal healthy subjects and were significantly elevated in cardiac transplant recipients (18.8 +/- 3.9 pmol/l, n = 12) and in patients with dialysis-independent (8.8 +/- 1.5 pmol/l, n = 11) or dialysis-dependent (41.6 +/- 8.8 pmol/l, n = 14) chronic renal failure. Similarly, in these groups of patients plasma levels of atrial natriuretic peptide were also significantly raised when compared with those in the group of normal healthy subjects. 2. The plasma level of atrial natriuretic peptide was significantly higher than that of brain natriuretic peptide in normal subjects and in patients with dialysis-independent chronic renal failure, with ratios (atrial natriuretic peptide/brain natriuretic peptide) of 2.8 +/- 0.2 and 2.2 +/- 0.3, respectively. However, in both cardiac transplant recipients and patients on dialysis plasma levels of atrial natriuretic peptide and brain natriuretic peptide were similar, with ratios of 1.3 +/- 0.2 and 1.0 +/- 0.1, respectively, in these two groups. 3. Plasma levels of brain natriuretic peptide and atrial natriuretic peptide were significantly correlated in the healthy subjects and within each group of patients. When all groups were taken together, there was an overall correlation of 0.90 (P < 0.001, n = 73).(ABSTRACT TRUNCATED AT 250 WORDS)     

Cerebrospinal fluid levels of catechols in patients with neurogenic orthostatic hypotension

In multiple system atrophy (MSA) and pure autonomic failure (PAF), orthostatic hypotension (OH) results from deficient noradrenaline release from sympathetic nerves during standing. Post-mortem findings have indicated loss of central noradrenergic cells in both diseases. The present study sought in vivo neurochemical evidence for central noradrenergic deficiency in patients with OH due to MSA or PAF. A total of 28 patients with OH (18 with MSA; 10 with PAF) had cerebrospinal fluid and blood sampled for levels of noradrenaline and its neuronal metabolite dihydroxyphenylglycol. A control group of 44 subjects included 10 elderly normal volunteers, 10 patients with Alzheimer's disease, 18 patients with dysautonomia (postural tachycardia syndrome or neurocardiogenic syncope) and six patients with MSA in the absence of OH. Patients with OH had lower cerebrospinal fluid concentrations of noradrenaline (0.53+/-0.07 nmol/l) and dihydroxyphenylglycol (6.52+/-0.46 nmol/l) than did control subjects (0.90+/-0.09 and 9.64+/-0.46 nmol/l respectively; P =0.0001). The MSA+OH group had higher plasma levels of both catechols (noradrenaline, 1.31+/-0.16 nmol/l; dihydroxyphenylglycol, 5.08+/-0.43 nmol/l) than did the PAF group (noradrenaline, 0.38+/-0.08 nmol/l; dihydroxyphenylglycol, 2.53+/-0.30 nmol/l; P <0.001), despite similarly low cerebrospinal fluid levels. Among MSA patients, those with OH had lower cerebrospinal fluid levels of noradrenaline and dihydroxyphenylglycol than those without OH (noradrenaline, 1.71+/-0.64 nmol/l; dihydroxyphenylglycol, 10.41+/-1.77 nmol/l respectively; P =0.006). The findings are consistent with central noradrenergic deficiency in both MSA+OH and PAF. In MSA, central noradrenergic deficiency seems to relate specifically to OH.     

Effect of haemodialysis on plasma levels of brain natriuretic peptide in patients with chronic renal failure.

1. Plasma human brain natriuretic peptide-like immunoreactivity (hBNP-li) was measured in ten patients with chronic renal failure before and after 4 h of haemodialysis. 2. Plasma hBNP-li was elevated in all patients before dialysis (mean +/- SEM 21.0 +/- 3.8 pmol/l) compared with healthy control subjects (1.3 +/- 0.2 pmol/l, n = 11), but showed considerable inter-patient variability. Before dialysis plasma hBNP-li bore no relationship to the serum creatinine level or to the mean blood pressure. 3. Plasma hBNP-li fell significantly (P = 0.04) during 4 h of haemodialysis. The fall in plasma hBNP-li correlated significantly with the degree of postural blood pressure drop (r2 = 0.44, P = 0.05) and with the fall in body weight (r2 = 0.64, P less than 0.01) after haemodialysis. In all patients, plasma hBNP-li at the end of treatment remained above that in healthy subjects. 4. There was no significant correlation between the fall in plasma hBNP-li and the fall in serum creatinine level, and between the fall in plasma hBNP-li and the fall in supine systolic or diastolic blood pressure, during haemodialysis. 5. We have shown that plasma hBNP-li is elevated in patients with chronic renal failure and is decreased during haemodialysis. The fact that the plasma hBNP-li was not reduced to normal by haemodialysis despite restoration to normovolaemia gives tentative support to the view that, in addition to hypervolaemia, another factor may also be responsible for the elevated plasma hBNP-li seen in these patients.     

Neuropeptide Y as a plasma marker for phaeochromocytoma, ganglioneuroblastoma and neuroblastoma.

1. We investigated the usefulness of neuropeptide Y as a plasma marker for phaeochromocytoma, ganglioneuroblastoma and neuroblastoma using a simple and highly sensitive r.i.a. for human neuropeptide Y. 2. Plasma immunoreactive neuropeptide Y concentrations were measured without extraction in plasma samples (100 microliters) from patients with various diseases. 3. The plasma immunoreactive neuropeptide Y concentration in patients with phaeochromocytoma (172.3 +/- 132.4 pmol/l, mean +/- SD, n = 23) was significantly higher than that in healthy adult subjects (40.1 +/- 10.1 pmol/l, n = 40, P < 0.0001). The plasma immunoreactive neuropeptide Y concentrations in patients with ganglioneuroblastoma (590.7 +/- 563.6 pmol/l, n = 6) and patients with neuroblastoma (566.9 +/- 524.4 pmol/l, n = 15) were significantly higher than those in control children (1-9 years old, 82.2 +/- 39.9 pmol/l, n = 72, P < 0.0001). 4. The plasma immunoreactive neuropeptide Y concentration in patients with essential hypertension (34.0 +/- 3.7 pmol/l, n = 18) was within the normal range, but in patients with chronic renal failure undergoing maintenance haemodialysis (192.1 +/- 68.0 pmol/l, n = 25) and in non-dialysed patients with chronic renal failure (85.1 +/- 23.1 pmol/l, n = 7) it was significantly higher than that in healthy adult subjects (P < 0.0001). 5. Eighty-seven per cent of the patients with phaeochromocytoma, 67% of the patients with ganglioneuroblastoma and 80% of the patients with neuroblastoma showed plasma immunoreactive neuropeptide Y concentrations higher than the upper limits in the control subjects [62 pmol/l (adult) and 160 pmol/l (children)].(ABSTRACT TRUNCATED AT 250 WORDS)     

Vitamin D from skin: contribution to vitamin D status compared with oral vitamin D in normal and anticonvulsant-treated subjects

1. The plasma 25-hydroxycholecalciferol [25-(OH)D3] response to measured u.v. irradiation applied thrice weekly for 10 weeks was investigated in normal and in anticonvulsant-treated subjects. 2. Levels of plasma 25-(OH)D3 achieved after u.v. irradiation were similar in both normal and anticonvulsant-treated subjects, suggesting that hepatic microsomal enzyme induction does not lead to low plasma 25-(OH)D3 concentrations. 3. Cholecalciferol was present in plasma of normal subjects in a very low concentrations (less than 5.0 nmol/l) and did not increase until plasma 25-(OH)D3 levels exceeded 62.5 nmol/l. 4. Cholecalciferol occurred in significant concentrations in plasma during whole body u.v. irradiation or during oral dosage of 62.5 nmol (100 i.u) or more daily. 5. Plasma 25-(OH)D3 concentrations reached a steady state after 5-6 weeks of u.v. irradiation or of oral intake within the usual intake range. 6. Cholecalciferol synthesis in skin calculated from the steady-state equation was 0.0015 +/- 0.0008 nmol/mJ. 7. Cholecalciferol synthesis in skin was also calculated from the oral dosage required to yield the same plasma 25-(OH)D3 concentration as u.v. irradiation and was 0.0024 +/- 0.0018 nmol/mJ. 8. Rates of cholecalciferol synthesis calculated from these data suggest that many of the population of England receive insufficient u.v. irradiation to maintain vitamin D status throughout the year.     

Adrenaline secretion during exercise

By studying six normal subjects during graduated treadmill exercise, we have confirmed that there is very little rise in venous plasma adrenaline levels during mild or moderate exercise. During a second study, adrenaline was infused intravenously in six resting subjects at a rate of 0.025 micrograms min-1 kg-1. This elevated the basal plasma adrenaline level from 0.28 +/- 0.04 nmol/l to 0.92 +/- 0.16, 1.16 +/- 0.20 and 1.28 +/- 0.19 nmol/l at 3, 5 and 7 min after the start of the infusion. The same adrenaline infusion was repeated in the same subjects 7 min after they started moderate exercise at a constant rate on a static exercise bicycle. Just before the start of the infusion, 7 min after the onset of exercise, plasma adrenaline had risen to 0.36 +/- 0.07 nmol/l. This rose to 1.86 +/- 0.30, 1.98 +/- 0.26 and 2.19 +/- 0.29 nmol/l at 3, 5 and 7 min after the start of this second infusion. Five minutes after the end of the infusion, while the subjects were still exercising, the mean level was 0.56 +/- 0.04 nmol/l. The venous plasma level of adrenaline is the result of a balance between the secretion of adrenaline by the adrenal medulla and the clearance of adrenaline from plasma. Our results suggest that the lack of any significant rise in plasma adrenaline during moderate exercise does not result from an accelerated clearance of adrenaline by exercising tissue. The clearance rate of adrenaline from plasma is reduced during exercise. There is no significant increase in secretion by the adrenal medulla in response to the stimulus of mild or moderate exercise.     

Metabolic clearance rate of arginine vasopressin in severe chronic renal failure.

1. The metabolic clearance rate of arginine vasopressin was determined using a constant infusion technique in normal subjects and patients with chronic renal failure immediately before commencing dialysis. Endogenous arginine vasopressin was suppressed in all subjects before the infusion with a water load. 2. Plasma arginine vasopressin concentrations were determined using a sensitive and specific radioimmunoassay after Florisil extraction. The detection limit of the assay was 0.3 pmol/l, and intra- and inter-assay coefficients of variation at 2 pmol/l were 9.7% and 15.3%, respectively. 3. In normal subjects, the metabolic clearance rate was determined at two infusion rates producing steady-state concentrations of arginine vasopressin of 1.3 and 4.4 pmol/l. In the patients with renal failure, a single infusion rate was used, producing a steady-state concentration of 1.5 pmol/l. 4. At comparable plasma arginine vasopressin concentrations, metabolic clearance rate was significantly reduced in patients with renal failure (normal 1168 +/- 235 ml/min versus renal failure 584 +/- 169 ml/min; means +/- SD; P < 0.001). 5. Free water clearance was significantly reduced in normal subjects during the arginine vasopressin infusion from 8.19 +/- 2.61 to -1.41 +/- 0.51 ml/min (P < 0.001), but was unchanged in the patients with renal failure after attaining comparable plasma arginine vasopressin concentrations. 6. In normal subjects there was a small but significant fall in metabolic clearance rate at the higher steady-state arginine vasopressin concentration (1168 +/- 235 ml/min at 1.3 pmol/l versus 1059 +/- 269 ml/min at 4.4 pmol/l; P = 0.016).(ABSTRACT TRUNCATED AT 250 WORDS)     

Abnormal 3,4-dihydroxyphenylalanine (dopa) concentrations in plasma and urine of patients with cystic fibrosis

Plasma and urine concentrations of the free amino acid 3,4-dihydroxyphenylalanine (dopa) were determined in a blind study in 16 children and adolescents with cystic fibrosis (CF), eight heterozygote parents of these children and in 11 healthy subjects who served as controls. To exclude any drug interference with catecholamine metabolism and to evaluate a tentative basic metabolic alteration in cystic fibrosis, the same determinations were done in 11 newly diagnosed infants (age 1-84 months). Free plasma dopa was significantly (P less than 0.01) elevated in CF (27.0 +/- 6.1 nmol l-1 vs. 19.1 +/- 5.0 nmol l-1 in the controls); heterozygotes had the lowest concentration: 11.5 +/- 5.8 nmol l (P less than 0.01 compared with normals). Increased plasma dopa concentrations were measured in the newly diagnosed infants (35.4 +/- 16.9 nmol l-1). Renal dopa clearance was the same in cystic fibrosis (9.26 +/- 5.71 ml min-1 1.73 m-2) and controls (10.87 +/- 2.46 ml min-1 1.73 m-2). A concomitant elevation of metabolic products as dopamine and noradrenaline in plasma and urine was noticed. These data are consistent with a dopa abnormality in this genetic disease.     

Serum transferrin receptor assay in iron deficiency anaemia and anaemia of chronic disease in the elderly

The most common cause of anaemia in the elderly is anaemia of chronic disease (ACD). However, iron deficiency anaemia (IDA) may coexist, and can be difficult to diagnose. The serum transferrin receptor (sTfR) blood test may be a better indicator of iron status as it is not affected by inflammation nor by advancing age. We evaluated it in four groups (10 males, 10 females each): 'young' controls, 'elderly' controls, IDA and ACD. All patients in the IDA group had elevated sTfR levels (mean +/- SD 65.2 +/- 17.7 nmol/l). All 'young' controls had normal sTfR (22.3 +/- 7.3 nmol/l) and ferritin levels (92.7 +/- 61.1 micrograms/l). Although all subjects in the 'elderly' controls and ACD group had normal, and raised or normal serum ferritin, respectively (88 +/- 62.3 micrograms/l; 631.2 +/- 509.5 micrograms/l), three (15%) 'elderly' controls and four (20%) ACD patients had raised sTfR levels, suggesting depleted iron stores. Bone-marrow aspirates were available in 3/4 ACD patients with raised sTfR. Haemosiderin was absent in two. The sTfR blood test is comparable to serum ferritin in diagnosing IDA in the elderly but also seems capable of differentiating ACD from IDA. Its potential as a non-invasive test of iron status, especially in elderly anaemic patients, deserves further evaluation.     

Plasma trypsin in chronic pancreatitis and pancreatic adenocarcinoma.

We have used a simple and precise radioimmunoassay to measure trypsin in human plasma. Fasting plasma trypsin concentrations were extremely low in patients with chronic pancreatitis with steatorrhoea (5 +/- 2 ng/ml) when compared to healthy controls (86 +/- 7 ng/ml, p less than 0.001). In patients with chronic pancreatitis but no steatorrhoea basal plasma trypsin levels were similar to those of the normal controls (99 +/- 25 ng/ml). A small but significant postprandial rise in plasma trypsin concentrations was observed in normal subjects (mean increment 15 +/- 4%, p less than 0.005, paired t test) but was absent in patients with chronic pancreatitis with steatorrhoea. In contrast to exocrine deficient chronic pancreatitis, other malabsorptive conditions associated with steatorrhoea (active coeliac disease and acute tropical sprue) demonstrated mean fasting trypsin concentrations similar to controls. Patients with adenocarcinoma of the pancreas had basal trypsin concentrations similar to healthy subjects as did patients with adenocarcinoma of the stomach, colon, rectum, brochus, and breast. In some cases measurement of plasma trypsin may be of help in the differential diagnosis of steatorrhoea.     

Plasma glycolate concentrations under conditions of dialysis

Plasma glycollate and oxalate concentrations were measured in 20 patients undergoing chronic haemodialysis treatment. The mean plasma glycollate level was 173.7 +/- 52.9 mumol/l, which was not significantly different from the normal value (means = 145.8 +/- 37.8 mumol/l). The mean plasma oxalate concentration (means = 128.7 +/- 25.6 mumol/l) was about 8 times higher than the value found in normal volunteers (means = 16.8 +/- 6.0 mumol/l). During haemodialysis lasting for 6 hours the plasma oxalate concentration decreased by 53.5%. However, no decline in plasma glycollate levels was noted. Since glycollate was not found in ultrafiltrates obtained in vivo, it is concluded that glycollate is not eliminated during haemodialysis treatment.     

Plasma level and renal clearance of oxalate in normal subjects and in patients with primary hyperoxaluria or chronic renal failure or both.

1. Plasma oxalate has been measured by a radioisotopic method applicable to all concentrations of plasma oxalate and renal function, and also by an enzymatic method which was only applicable to raised concentrations of plasma oxalate. 2. Where the two methods could be applied simultaneously, the agreement between them was good. 3. Plasma oxalate was 86% ultrafiltrable at concentrations of up to 44 micromol/l. 4. Oxalate clearance and the exchangeable oxalate pool were also measured. The ratio of oxalate clearance to creatinine clearance was greater than unity in most normal subjects and patients. 5. These methods were used in normal subjects and in patients with primary hyperoxaluria and/or chronic renal failure. A raised plasma oxalate concentration was found in both conditions. Chronic renal failure is probably the most common cause of a raised plasma oxalate.     

Plasma fibronectin concentrations in morbidly obese patients

Plasma fibronectin concentrations and liver morphology were investigated in 45 morbidly obese subjects (median overweight 88%) and in 42 normal weight controls, matched for sex and age. A significantly (P less than 0.01) raised plasma fibronectin concentration (median 464 mg/l, range 276-862 mg/l) was found in the obese subjects when compared with concentrations in the controls (median 348 mg/l, range 164-536 mg/l). Plasma fibronectin concentrations of the obese patients correlated significantly to their degree of overweight (r = 0.33, P less than 0.05) as well as to the degree of fatty change found in their liver biopsies (r = 0.33, P less than 0.05). Significantly (P less than 0.05) elevated plasma fibronectin concentrations even in obese subjects without hepatic fatty change indicate that liver fat accumulation is no prerequisite of the obesity-related elevation of plasma fibronectin. Raised plasma fibronectin concentration in obesity may more readily be explained by an increased fibronectin formation by lipocytes.     

Calcium and phosphate metabolism in acute falciparum malaria.

1. Mineral homeostasis was investigated in 172 Thai adults with acute falciparum malaria at presentation (87 males, 85 females; mean age 30 years), and prospectively in a subgroup of 10 severely ill patients. 2. Mild, asymptomatic hypocalcaemia (corrected plasma calcium concentration 1.79-2.11 mmol/l) was found in 61 cross-sectional study patients (35.5%), with no difference between those with uncomplicated (2.16 +/- 0.10 mmol/l, mean +/- SD, n = 89) and severe (2.18 +/- 0.15 mmol/l, n = 83, P = 0.36) infections. Six prospectively studied patients were hypocalcaemic during treatment; simultaneous serum intact parathormone concentrations were inappropriately low (less than 5.0 pmol/l), but rose in three patients to high levels (11.8-16.4 pmol/l) on the fifth day. 3. Plasma phosphate concentration was decreased (less than 0.80 mmol/l) on admission in 74 patients (43.0%) and increased (greater than 1.45 mmol/l) in 15 (8.7%). Severe phosphate depletion (plasma phosphate concentration less than 0.30 mmol/l) occurred in 14 patients, of whom 11 had severe infections. Serum phosphate concentrations in the prospective study patients on admission (0.59 +/- 0.23 mmol/l) correlated significantly with the simultaneous renal threshold phosphate concentration (0.68 +/- 0.33 mmol/l; r = 0.607, P less than 0.025) and both parameters rose in parallel during treatment. 4. Plasma magnesium concentrations were normal (0.75-1.05 mmol/l) in 108 patients (62.8%); 45 cases (26.1%) had hypermagnesaemia and 19 (11.0%) had hypomagnesaemia. 5. These data suggest that mild hypocalcaemia is common in malaria regardless of disease severity; a depressed parathormone response may contribute. Despite malaria-associated haemolysis, hypophosphataemia is also common, but can be severe.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of aminophylline on plasma and urinary catecholamine levels during heavy leg exercise in healthy young men

1. Methylxanthines have been shown to elevate the basal plasma level and/or urinary excretion of noradrenaline (NA) and adrenaline (ADR) in healthy subjects. The present study addressed the hypothesis that the methylxanthine aminophylline also augments plasma and urinary catecholamines during increased sympathoadrenal activity. 2. Eleven healthy young men performed a maximal 2 h bicycle exercise twice, after double-blind intravenous administration of placebo or aminophylline. Femoral venous plasma and urinary concentrations of NA and ADR were analysed in samples representing basal state, exercise and recovery, using liquid chromatography with electrochemical detection. 3. Leg exercise induced eight- and six-fold increases in the plasma concentrations of NA and ADR, respectively, and seven- and four-fold increases in the urinary concentrations of NA and ADR, respectively, indicating that sympathoadrenal activity was considerably elevated. 4. After aminophylline (mean plasma concentration 20-35 mumol/l), the plasma concentrations of NA (P less than 0.001) and ADR (P less than 0.05) were independently higher at rest, during exercise and during recovery, in comparison to after placebo; the mean exercise plasma level of NA was increased by the drug from 13 +/- 1 to 21 +/- 2 nmol/l and the corresponding level of ADR from 2.1 +/- 0.4 to 2.9 +/- 0.5 nmol/l. Also urinary NA (P less than 0.01) and ADR (P less than 0.05) were elevated by aminophylline; the exercise concentrations of NA in the urine were 75 +/- 8 and 97 +/- 10 mumol/mol of creatinine after placebo and aminophylline, respectively, and the corresponding levels of ADR were 12 +/- 3 and 16 +/- 3 mumol/mol of creatinine, respectively.