P38 mitogen-activated protein kinase mediates hexosamine-induced TGFbeta1 mRNA expression in human mesangial cells.

AIMS/HYPOTHESIS: The hexosamine pathway has been implicated in the induction of TGFbeta1 expression and in the pathophysiology of diabetic glomerulopathy. Glucose-induced TGFbeta1 expression is mediated by p38 mitogen-activated-protein-kinase (p38-MAPK) and this kinase is activated in the diabetic glomeruli. We examined whether the p38-MAPK is implicated in hexosamine-induced TGFbeta1 mRNA expression in human mesangial cells. GFAT overexpression induced an increase in p38-MAPK activation after 6 and 12 h incubation in normal glucose, and this was prevented by the GFAT inhibitor azaserine. Furthermore, high glucose enhanced p38-MAPK activation in GFAT tranfected cells ( p

Biochemical markers in the management of suspected acute myocardial infarction in the emergency department.

OBJECTIVES: To compare cardiac troponin T, myoglobin, CK, CKMB activity, CKMB mass and the initial electrocardiogram in the early diagnosis of myocardial infarction in the emergency department. Methods-Biochemical markers were measured at presentation in patients with a possible diagnosis of acute myocardial infarction. Based on the clinical notes, patients were grouped as "definite myocardial infarction" (n = 50), "definite no myocardial infarction" (n = 81) and "uncertain" (n = 96). Sensitivity and specificity and positive and negative predictive values were calculated using the 131 patients with definitely present or absent myocardial infarction. RESULTS: The initial electrocardiogram was more sensitive than any of the markers in the first six hours from symptom onset-sensitivity 74% (95%CI 61% to 88%). The positive predictive value of the initial electrocardiogram was 97% in the first six hours; the markers ranged from 47% to 67%. The negative predictive value of the initial electrocardiogram was 85% in the first six hours; the markers ranged from 61% to 70%. Four patients with non-diagnostic electrocardiograms presenting beyond six hours after pain onset had a myocardial infarct detected by at least three of the biochemical markers in each case. CONCLUSIONS: The electrocardiogram is of more diagnostic use than biochemical markers in the first six hours after the onset of pain, but biochemical markers give additional positive diagnostic information in patients presenting later than this. The negative predictive accuracy of biochemical markers is too low for a single sample to be useful for excluding myocardial infarction in the first six hours after onset of symptoms.

Sulfate homeostasis, NaSi-1 cotransporter, and SAT-1 exchanger expression in chronic renal failure in rats.

BACKGROUND: It is known that hypersulfatemia, like hyperphosphatemia, occurs in chronic renal failure (CRF). The aim of this study was to assess the effects of CRF on sulfate homeostasis and on sodium sulfate cotransport (NaSi-1) and sulfate/oxalate-bicarbonate exchanger (Sat-1) expression in the kidney. In addition, sulfate homeostasis was compared with phosphate homeostasis. METHODS: Experimental studies were performed in adult male rats at three and six weeks after 80% subtotal nephrectomy (Nx) or sham-operation (S) (N = 9 per group). Transporter protein and mRNA expressions were measured by Western blot and RNase protection assay (RPA), respectively. Results were quantitated by densitometric scanning (Western) and electronic autoradiography (RPA), and were expressed in densitometric units (DUs; Western) and cpm (RPA). RESULTS: Creatinine clearance was lower in Nx-3 compared with S-3 rats (0.23 vs. 0.51 mL/min/100 g body weight, P < 0.001) and was further impaired in Nx-6 rats (0.15 vs. 0.48, P < 0.001). Sulfatemia was significantly higher in Nx-3 rats (1.08 vs. 0.84 mmol/L, P < 0.05) and further increased in Nx-6 rats (1.42 vs. 0.90 mmol/L, P < 0.01). Fractional sulfate excretion (FESO4) was increased by twofold in Nx-3 and Nx-6 rats compared with corresponding S rats. Phosphatemia did not differ between Nx-3 rats and controls, but was increased in Nx-6 rats (P < 0.01). Total amounts of both NaSi-1 and Sat-1 proteins were significantly decreased in both Nx-3 and Nx-6 rats when compared with controls. However, NaSi-1 protein and mRNA densities did not significantly change in Nx-3 rats, but were significantly increased in Nx-6 rats when compared with controls (4.8 vs. 3.7 DU/microg protein, P < 0.05, and 7.1 vs. 2.8 cpm/microg RNA, P < 0.01, respectively, for protein and mRNA). In contrast to NaSi-1, Sat-1 protein density was significantly decreased both in Nx-3 (2.9 vs. 3.6 DU/microg protein, P < 0.05) and Nx-6 rats (2.4 vs. 3.4 DU/microg protein, P < 0.05), and Sat-1 mRNA density significantly decreased in Nx-6 rats (10.7 vs. 14.7 cpm/microg RNA, P < 0.05). Na-PO4 cotransporter (NaPi-2) protein total abundance and density were decreased at three and six weeks in Nx rats. CONCLUSIONS: These results demonstrate that both NaSi-1 and Sat-1 total protein abundances are decreased in CRF, which may contribute to the increase in fractional sulfate excretion. Strikingly, NaSi-1 density was not decreased in CRF three weeks after Nx, and furthermore, increased six weeks after Nx, in contrast to NaPi-2 density, which was decreased at both times. The significance of this difference remains to be determined, but may explain why hypersulfatemia occurs earlier than hyperphosphatemia in CRF.

Acid-base and endocrine effects of aldosterone and angiotensin II inhibition in metabolic acidosis in human patients.

Chronic metabolic acidosis (CMA) in human beings is characterized by increased renin-angiotensin-aldosterone (RAA) activity and cortisol secretion as well as nitrogen wasting. The purpose of this study was to examine whether and to what extent increased RAA activity (i.e., angiotensin II or aldosterone) regulates acid-base equilibrium in CMA and thus might co-determine the severity of acidosis. CMA was induced in 8 normal subjects by oral NH4Cl administration (2.1 mmol/kg body weight per day) for 7 days, followed by a 7-day period of spironolactone (100 mg, 4 times a day by mouth), followed by a 4-day period of spironolactone and losartan (100 mg, every day by mouth). NH4Cl feeding was continued during all study periods. Spironolactone resulted in exacerbation of acidosis ((HCO3)p decreased from 19.8+/-0.4 mmol/L to 17.7+/-0.6 mmol/L, P<.005) because of a large increase in endogenous acid production, as evidenced by significant increases in net acid excretion (116 to 185 mmol/day, P<.005), urinary anion gap (+31 mEq/day, P<.05), and sulfate excretion (+32 mEq/day, P<.05). Plasma potassium increased from 4.2 to 4.6 mmol/L (P<.05) because of decreased urinary potassium excretion (from 108 to 92 mmol/day, P<.05). Plasma angiotensin II, cortisol, aldosterone, urinary aldosterone, urinary tetrahydrocortisol, free cortisol, and nitrogen excretion increased significantly. The subsequent addition of losartan to spironolactone administration resulted in further exacerbation of acidosis ((HCO3)p decreased to 15.7+/-0.4 mmol/L, P<.05) and hyperkalemia (5.0 mmol/L, P<.05) with no change in plasma anion gap. Renal potassium excretion decreased from 92 to 73 mmol/day (P<.05) on day 1. Exacerbation of acidosis was accounted for by a renal mechanism, as evidenced by the significant decrease in net acid excretion and unchanged urinary unmeasured anion and nitrogen excretion. We conclude the following: (1) AT-1 blockade by losartan exacerbates acidosis by inducing a distal-tubular acidification defect. Angiotensin II is an important modulator of the renal acid excretory response to CMA in human beings. (2) Inhibition of aldosterone action by spironolactone in CMA results in an increase in endogenous acid production and exacerbates acidosis by a non-renal mechanism that is mediated, at least in part, by exacerbated hyperglucocorticoidism.

Serum sialic acid and its relationship to various haematological parameters, including erythrocyte sedimentation rate.

Serum total sialic acid (TSA) has been reported to be a marker or risk factor for cardiovascular disease. The reason for this is not clear, although it has been suggested that serum TSA is a marker of the acute phase response. We measured serum TSA and various haematological parameters in 40 subjects. Significant correlations of serum TSA with erythrocyte sedimentation rate (ESR) (r = 0.65, P < 0.0001), platelet count (r = 0.65, P < 0.0001) and neutrophil count (r = 0.33, P < 0.05) were found. There was an inverse correlation with haemoglobin concentration (r = -0.62, P < 0.0001) and erythrocyte count (r = -0.42, P < 0.01).

Plasma fibrinogen and its relationship to plasma sialic acid in non-insulin-dependent diabetes mellitus.

Serum or plasma sialic acid (SA) has been shown to be a possible risk factor for cardiovascular disease and to be elevated in diabetes mellitus. We postulated that plasma SA may be related to plasma fibrinogen, another reputed cardiovascular risk factor. We decided to test this hypothesis in 27 patients with non-insulin-dependent diabetes mellitus (NIDDM) and 27 age- and sex-matched control subjects. Plasma fibrinogen was significantly elevated in the diabetic patients compared with the control subjects (3.4 +/- 1.5 g/l versus 2.2 +/- 0.6 g/l, P < 0.001). Similarly, plasma SA was elevated in the diabetic patients in comparison with the control subjects (0.74 +/- 0.14 g/l versus 0.62 +/- 0.08 g/l, P < 0.001). There was a strong univariate correlation between plasma fibrinogen and plasma SA in both NIDDM patients (r = 0.80, P < 0.001) and control subjects (r = 0.54, P < 0.01).

Serum sialic acid in patients with multiple myeloma.

Serum sialic acid (SA) has been reported recently to be elevated in a number of malignant conditions. To test the hypothesis that serum SA may be elevated in patients with multiple myeloma we looked at 34 myeloma patients (17 females and 17 males) and 22 controls (11 females and 11 males). The mean age of the myeloma patients was 61.2 +/- 10.9 years versus 58.9 +/- 12.6 years for the control group. There was a highly significant difference between the serum SA in the myeloma patients compared to the control group; 103.5 +/- 32.8 mg/dL versus 78.9 +/- 10.2 mg/dL respectively (P < 0.001). There was a significant correlation between serum SA and serum total protein and globulin concentration in the IgA myeloma patients, and a significant correlation between serum paraprotein quantity and globulin concentration in the IgM patients.

Serum lipids, acute phase proteins and serum cholinesterase in normal subjects.

Although serum cholinesterase (CHE) is elevated in some hyperlipidaemic subjects, the relationship between serum CHE and lipids in normolipidaemic subjects is scanty. Furthermore, serum CHE is reduced in conditions in which there is an acute phase response. Serum CHE activity was measured in 46 normal individuals (22 males and 24 females). There was no significant difference between the activity of serum CHE in males or females being 6.2 +/- 1.8 U1(-1) vs. 6.4 +/- 1.5 U1(-1) respectively (mean +/- SD). There was, however, a significant correlation between serum CHE and subject age (Spearman rho 0.35, p < 0.05). There was also a significant correlation between serum CHE and serum nonfasting triglyceride concentration (rho 0.34, p < 0.05) and also apolipoprotein B (rho 0.38, p < 0.05) but not serum cholesterol or HDL-cholesterol. Five serum acute phase proteins were measured namely serum alpha-1 antichymotrypsin (ACT), alpha-1-acid-glycoprotein (AGP), alpha-2-macroglobulin (AMG), C-reactive protein (CRP), haptoglobin (HAP). Only serum AGP showed a significant negative correlation with serum CHE (rho - 0.43, p < 0.02).

Serum total sialic acid and acute phase proteins in elderly subjects.

Serum total sialic acid has gained recent interest as a cardiovascular risk factor. We measured serum total sialic acid and three acute phase proteins; C-reactive protein, alpha 1-antichymotrypsin and alpha 1-acid glycoprotein in 37 geriatric patients (age 80.1 +/- 7.0 years) and 50 younger subjects (age 40.3 +/- 11.4 years). Serum total sialic acid was higher in the geriatric subjects 2.41 +/- 0.39 mmol/l versus 2.04 +/- 0.35 mmol/l, P < 0.04. Serum alpha 1-acid glycoprotein, alpha 1-antichymotrypsin and C-reactive protein were also elevated in the geriatric patients; serum alpha 1-acid glycoprotein being 1.16 +/- 0.32 g/l versus 0.41 +/- 0.28 g/l, P < 0.0001, serum alpha 1-antichymotrypsin being 0.80 +/- 0.20 g/l versus 0.52 +/- 0.10 g/l, P < 0.0001 and serum C-reactive protein being 9.71 +/- 21.0 mg/l versus 4.73 +/- 1.30 mg/l, P < 0.04. There was a correlation with serum total sialic acid and serum alpha 1-acid glycoprotein and alpha 1-antichymotrypsin in the geriatric subjects and with alpha 1-acid glycoprotein, alpha 1-antichymotrypsin and C-reactive protein in the younger group.

Plasma sialic acid and acute-phase proteins in patients with myocardial infarction.

Plasma total sialic acid (TSA) and lipid-associated sialic acid (LASA) were measured in 19 patients with a myocardial infarction (MI) on days 1, 2, and 5 and in 19 normal subjects. On each day plasma TSA was elevated in the MI patients as compared with that of normal subjects, although no significant difference was seen in the plasma LASA between the two groups. The following plasma acute-phase proteins were also assayed in the MI patients and the normal subjects: C-reactive protein (CRP), alpha-1 acid glycoprotein (AGP), alpha-1 antichymotrypsin (ACT), alpha-2 macroglobulin (AMG), and fibrinogen (FIB). Significantly elevated plasma concentrations were found in the MI patients as compared with normal subjects. Furthermore, a significant correlation was found between some of these plasma acute-phase proteins (ACT, AMG, and FIB) and plasma TSA in the MI patients and also in normal subjects (ACT, AMG, CRP, and FIB). However, no significant difference was noted in any of the plasma acute-phase proteins, or plasma TSA, or plasma LASA between survivors and patients who died of their MI.

Raised concentration of plasma creatine kinase BB isoenzyme in myelodysplasia.

A 72 year old woman presented with a suspected myocardial infarction. An echocardiograph showed no acute changes but her plasma creatine kinase (CK) activity was increased at 343 U/l (< 175 normal range). The apparent creatine kinase-MB activity by a CK-M subunit immunoinhibition assay was 350 U/l. In view of the discrepancy between the total creatine kinase and CK-MB activity plasma creatine kinase electrophoresis studies were performed which showed not only a band of creatine kinase-MM but also a band of creatine kinase-BB, 53% of the total creatine kinase activity. No band of CK-MB was seen. It later transpired that the woman had myelodysplasia. It is suggested that premalignant and malignant haematological conditions should be considered in patients with an unexplained increase in plasma CK-BB.

The relationship of serum total sialic acid with serum acute phase proteins and lipoprotein (a) in patients with severe hypertriglyceridaemia.

Total serum sialic acid (TSA), recently shown to be a cardiovascular risk factor, was measured in 15 patients with severe hypertriglyceridaemia (fasting triglyceride > 2.3 mmol l-1) and 15 age and sex matched normal control subjects. To test the hypothesis that serum TSA is related in some way to serum acute phase proteins we also measured five acute phase proteins, namely alpha-1-antichymotrypsin (ACT), alpha-1-acid-glycoprotein (AGP), alpha-2-macroglobulin (AMG), C-reactive protein (CRP) and haptoglobin (HAP) in both groups. Of note was the significantly elevated serum TSA in the severely hypertriglyceridaemic group as compared to normal subjects. Serum TSA being 71.9 +/- 11.7 mg dl-1 and 59.6 +/- 10.2 mg dl-1 respectively (P < 0.01 Mann-Whitney test). Serum CRP was significantly elevated in the type IV patients as compared to controls (6.4 +/- 4.5 mg l-1 vs. 3.3 +/- 1.9 mg l-1 P < 0.05 Mann Whitney test) as was serum AMG (2.1 +/- 0.89 g l-1 vs. 1.5 +/- 0.53 g l-1 P < 0.05 Mann Whitney test). There was no correlation between serum TSA and lipoprotein (a) in either the normal or severely hypertriglyceridaemic subjects. We suggest that serum TSA could in part be related to hypertriglyceridaemia and serum acute phase proteins but that its property as a cardiovascular risk factor is not related to serum lipoprotein (a) concentrations.

Iron status, movement disorders, and acute phase response in elderly psychiatric patients.

The previously reported relation between iron deficiency and movement disorders was studied in a population with a high prevalence of both problems. There was no evidence of a direct statistical relation between iron deficiency and movement disorders. Significant associations were, however, found between movement disorders and features of the acute phase response to physiological stress. Indices of iron status are known to be affected by the acute phase response and it is suggested that the previously reported abnormalities in iron status may be secondary to this.

Erythrocyte, plasma total, ultrafiltrable and platelet magnesium in type 2 (non-insulin dependent) diabetes mellitus.

We studied plasma magnesium, plasma ultrafiltrable magnesium, erythrocyte and platelet magnesium in 28 non-insulin dependent (NIDDM) patients and 28 age and sex matched non-diabetic control subjects. The plasma magnesium concentration was significantly lower in the diabetic subjects as compared with the control subjects (0.67 +/- 0.09 mmol/l versus 0.72 +/- 0.07 mmol/l, P < 0.05) as was plasma ultrafiltrable magnesium (0.43 +/- 0.06 mmol/l versus 0.47 +/- 0.05 mmol/l, P < 0.01. Similarly, erythrocyte magnesium was lower in the diabetic subjects than the non diabetic controls, (0.17 +/- 0.03 nmol/10(6) cells versus 0.19 +/- 0.02 nmol/10(6) cells, P < 0.01. Platelet magnesium was higher in the diabetic subjects (48.3 +/- 19.1 umol/g platelet protein versus 36.6 +/- 22.2 umol/g platelet protein, P < 0.01). There was no significant difference between the % plasma ultrafiltrable magnesium with respect to total plasma levels between the diabetic and normal subjects (64.7 +/- 4.7% versus 65.8 +/- 3.2% respectively). There was no significant correlation between any of these parameters and systolic or diastolic blood pressure of HbA1C in the diabetics. Nor were there any significant differences in these magnesium parameters in patients with or without diabetic complications.

Evaluation of three assays for the determination of serum total sialic acid.

There is increasing clinical interest in the measurement of serum total sialic acid (TSA). There are a number of methods available but with little data suggesting the preferred technique. We evaluated three serum sialic acid assays: the Warren assay, the Svennerholm assay, and a commercially available enzymatic method. The analytical performances of the three assays were similar, except that the enzymatic assay had a greater analytical range than the other assays and better precision at low and high serum sialic acid concentrations. The enzymatic assay was readily automated for use on a Cobas Bio analyser but was substantially more expensive than the other two methods.

Serum sialic acid and acute phase proteins in type 1 and type 2 diabetes mellitus.

Serum sialic acid is a risk factor for cardiovascular disease in the general population. Serum total sialic acid concentrations were therefore measured in 20 type 1 diabetic patients and in 20 age- and sex-matched non-diabetic subjects. Serum sialic acid were not significantly different in the type 1 diabetic patients and the normal subjects (2.00 +/- 0.37 vs. 1.98 +/- 0.67 mmol/l), but was significantly correlated with serum total cholesterol (r = 0.55, P < 0.02) and serum triglyceride concentration (r = 0.63, P < 0.01) in the type 1 diabetic patients. There was no relationship of sialic acid levels to age, duration of diabetes, smoking, body mass index, systolic or diastolic blood pressure, plasma glucose, serum fructosamine, or daily insulin dosage. Six of the type 1 diabetic patients with retinopathy had higher total serum sialic acid concentrations than those patients without retinopathy (2.38 +/- 0.33 vs. 1.85 +/- 0.26 mmol/l, P < 0.01). A further study of 16 type 1 and 16 type 2 diabetic patients matched for serum fructosamine and blood glucose concentrations and without tissue complications showed that the serum total sialic acid concentration was significantly higher in the type 2 diabetic patients compared with the type 1 patients (2.32 +/- 0.41 vs. 1.84 +/- 0.24 mmol/l, P < 0.001). Although the serum concentrations of the non-sialylated acute phase protein, C-reactive protein, was higher in type 2 than type 1 diabetes, sialylated acute phase protein levels did not explain differences in serum total sialic acid in diabetes.(ABSTRACT TRUNCATED AT 250 WORDS)

Serum sialic acid and acute-phase proteins in hypertriglyceridaemic patients showing the Frederickson's type IIB phenotype.

1. We have shown that serum total sialic acid is elevated in hypertriglyceridaemic patients showing the Frederickson's type IIB phenotype in comparison with normal subjects (2.30 +/- 0.34 versus 1.92 +/- 0.32 mmol/l, P < 0.02). Lipid-associated sialic acid was also elevated in the hypertriglyceridaemic group in comparison with the normal subjects (0.60 +/- 0.09 versus 0.35 +/- 0.04 mmol/l, P < 0.001). 2. We measured five serum acute-phase proteins in the hypertriglyceridaemic patients and the normal subjects, namely alpha 1-antichymotrypsin, alpha 1-acid glycoprotein, alpha 2-macroglobulin, C-reactive protein and haptoglobin. Serum alpha 2-macroglobulin was significantly elevated in the hypertriglyceridaemic patients compared with the normal subjects (2.1 +/- 1.0 versus 1.5 +/- 0.55 g/l, P < 0.05) as was serum C-reactive protein (5.9 +/- 3.5 versus 3.5 +/- 1.9 mg/l, P < 0.05). There were, however, no significant differences in the serum concentrations of alpha 1-antichymotrypsin, alpha 1-acid glycoprotein or haptoglobin between the two groups. 3. There was a significant correlation between serum total sialic acid and serum alpha 1-antichymotrypsin, alpha 1-acid glycoprotein and haptoglobin (Spearman correlation coefficients 0.74, 0.50 and 0.76, respectively) in the normal subjects, and there was a significant correlation between serum total sialic acid and serum alpha 1-antichymotrypsin and alpha 1-acid glycoprotein (Spearman correlation coefficients 0.72 and 0.84, respectively) in the hypertriglyceridaemic patients.