Second trimester amniotic fluid retinol in patients developing preeclampsia.

BACKGROUND: Retinol (ROH) is an essential micronutrient required for normal fetal development and an essential molecule for antioxidant processes. OBJECTIVE: To investigate the putative role of ROH as a marker of preeclampsia in early second trimester amniotic fluid (AF). MATERIALS AND METHODS: Case-control study comparing the concentration of ROH and other antioxidants such as uric acid, vitamin E and malondialdehyde (MDA) in second trimester AF in patients that later developed preeclampsia with normal pregnancies. RESULTS: The concentration of ROH in amniotic fluids of women that later developed preeclampsia was significantly higher than those of uncomplicated pregnancies (66.72 µg/l (49.00-70.56) vs. 44.4 µg/l (31.9-51.17), p < 0.05). No statistical significant difference was found in uric acid, vitamin E and MDA concentration. In the multivariate logistic regression, concentrations of ROH in amniotic fluids directly correlate with the risk of developing preeclampsia (OR 1.13, IC 0.01-1.26, p < 0.05). CONCLUSIONS: Second trimester AF ROH concentration was significantly higher in pregnancies that developed preeclampsia compared to normal pregnancies.

Physical training effects in renal transplant recipients.

INTRODUCTION: Several studies demonstrated the benefits of rehabilitation in uraemic patients. This study evaluates physical and psychosocial effects of exercise on renal transplant recipients (RTRs). PATIENTS AND METHODS: Eight RTRs were evaluated before and after an exercise training consisting of thirty 40-minute sessions, three times a week, performed with the interval training technique. RESULTS: Hospital Anxiety and Depression Scale (HADS) significantly decreased (p<0.04 and <0.008, respectively). Quality of life mean scores (SF-36 test) significantly increased (p<0.000). No differences were recorded for muscle and fat mass, maximal explosive power of the lower limbs, alkaline and acid phosphatase, parathormone (PTH), myoglobin, lipoprotein-A, glomerular filtration rate (GFR), at rest heart rate, and cardiac troponin. IL-6 decreased from 2.8±0.6 to 1.7±0.5 pg/mL (p<0.01). Resting MAP fell from 112±4 to 99±3 mmHg (p<0.02). The metabolic threshold rose from 33±4 to 43±5% (p<0.033). The blood lactate level at peak exercise increased from 5.2±0.9 to 6.2±0.7 mmol/L (p<0.012). The maximum oxygen uptake increased from 1200±210 to 1359±202 mL/min (p<0.05), iso-load oxygen uptake decreased from 1110±190 to 1007±187 mL/min (p<0.034). The maximum working capacity increased from 90±14 to 115±15 watts (p<0.000). CONCLUSION: This study suggests that an appropriate dose of physical training is a useful, safe and non-pharmacologic contribution to RTR treatment.

eSlide suite: an open source software system for whole slide imaging.

This short report briefly describes the principles underlying the telepathology technique known as whole slide imaging, and the design and implementation of a system for acquisition and visualisation of digital slides. The developed system, including an acquisition module and a visualisation module, is available as an open source on the Internet, together with sample acquired slides.

The nucleotide-independent Fe(III)-binding site is located on beta subunit of the mitochondrial F(1)-ATPase.

Upon separation of a crude preparation of beta subunit ("beta fraction") from mitochondrial F(1)-ATPase containing one equivalent of Fe(III) in the nucleotide-independent site (1Fe(III)-loaded MF(1)), Fe(III) is almost completely recovered. CD spectra show that "beta fraction" maintains the structural changes induced by Fe(III) in the whole enzyme. In accordance, EPR reveals that the Fe(III) site geometry is conserved in "beta fraction." Moreover, the EPR spectra of 1Fe(III)-loaded MF(1) and its "beta fraction" undergo similar changes of the line-shape upon Pi binding at the catalytic site, indicating that the Pi and Fe(III) are proximal on beta. Highly purified beta in nucleotide-free form binds 1mol of Fe(III)/mol of protein. MF(1) "freezed" by inhibitors with two beta in closed conformation and one beta in open or half-closed conformation binds 1mol of Fe(III)/mol of enzyme. Therefore, the Fe(III) site location in the unique beta subunit not adopting the closed conformation is proposed.

Red wine protects diabetic patients from meal-induced oxidative stress and thrombosis activation: a pleasant approach to the prevention of cardiovascular disease in diabetes.

BACKGROUND: Oxidative stress and thrombosis have been reported to be increased in diabetic patients and involved in the pathogenesis of cardiovascular complications. It has been demonstrated in diabetic patients that consumption of a meal is accompanied by the generation of an oxidative stress and of a hypercoagulable state. It is well recognized that red wine shows antithrombotic activity and that its ingestion increases plasma antioxidant capacity in man. In this study the possibility that red wine consumption may reduce the oxidative stress and thrombosis produced postprandially in diabetic patients has been evaluated. SUBJECTS AND METHODS: Twenty type 2 diabetic patients were studied during fasting consumption of 300 mL of red wine, or during a meal accompanied, or not, by red wine ingestion. RESULTS: Plasma glucose, insulin, triglycerides, total plasma radical-trapping capacity, activated factor VII and prothrombin fragments 1 + 2 were measured in basal state and at 60, 120 and 180 min after the start of each experiment. Low-density lipoprotein (LDL) oxidation was also evaluated at baseline and after 120 min Plasma glucose, insulin, triglycerides and LDL oxidation significantly increased, while the total plasma radical-trapping parameter significantly decreased during the meal test. Consumption of red wine in the fasting state significantly increased total plasma radical-trapping parameter activity, while wine ingestion with a meal counterbalanced the decrease of total plasma radical-trapping parameter and the increase of LDL oxidation. Meal consumption induced an increase in plasma prothrombin fragments 1 + 2 and activated factor VII in diabetic patients. Wine ingestion with the meal significantly reduced the production of both prothrombin fragments 1 + 2 and activated factor VII. Fasting consumption of red wine alone did not show effects on coagulation or LDL oxidation. CONCLUSION: This finding confirms that in the absorptive phase free radicals are produced in diabetic patients, which reduce serum antioxidant defences, increase LDL oxidation and activate the coagulation system. Red wine consumption during a meal significantly preserves plasma antioxidant defences and reduces both LDL oxidation and thrombotic activation. The consumption of a moderate amount of red wine during meals may have a beneficial effect in the prevention of cardiovascular disease in diabetic patients.

Systemic and intratubular effects of cyclosporin-A and tacrolimus on the rat kidney.

Cyclosporin-A and tacrolimus can cause hypertension and renal failure through endothelin receptors. The importance of tubular function was never investigated. The aim of this study was to compare the effects of intratubular injection of cyclosporin-A and tacrolimus with effects observed during systemic infusion. In 20 rats, either cyclosporin-A or tacrolimus was infused, 30 and 1 mg/kg i.v., respectively, in 30 min. Before and after administration, glomerular filtration rate, single nephron filtration rate, proximal and distal absolute reabsorption and percent reabsorption were measured by clearance and micropuncture techniques. In 22 other rats, single nephron filtration rate, absolute reabsorption, percent reabsorption, were measured at the last proximal and early distal tubules before and during intraluminal microinjection of either cyclosporin-A or tacrolimus. During cyclosporin-A and tacrolimus i.v. infusion, glomerular filtration rate fell from 536+/-43 to 448+/-37 microl/min (P<0.026) and from 408+/-33 to 284+/-81 microl/min (P<0. 02), single nephron filtration rate from 26.4+/-2.0 to 20.6+/-1.9 (P<0.002) and from 21.6+/-2.2 to 17.4+/-2.0 nl/min, respectively (P<0.02). The last proximal absolute reabsorption remained unchanged with cyclosporin-A (16.8+/-2.2 vs. 15.1+/-1.7 nl/min, P>0.444), but was slightly reduced by tacrolimus (14.4+/-1.7 vs. 11.3+/-1.7 nl/min, P<0.05). During microinjection, single nephron filtration rate was increased by cyclosporin-A (20+/-1 vs. 63+/-8 nl/min, P<0.0001), and tacrolimus (from 17+/-2 to 49+/-9 nl/min, P<0.0001), and so was reabsorption, independent of the sampling site. Cyclosporin-A and tacrolimus, indeed, raise single nephron filtration rate directly when injected intraluminally. Since this effect occurs in the direction opposite to that recorded during systemic infusion, it must be mediated through different pathways. The i.v. infusion of cyclosporin-A, but not tacrolimus, impairs glomerulo-tubular balance.

Meal-induced oxidative stress and low-density lipoprotein oxidation in diabetes: the possible role of hyperglycemia.

Oxidative stress and its contribution to low-density lipoprotein (LDL) oxidation have been implicated in the pathogenesis of vascular diabetic complications. However, the relationship between hyperglycemia, hyperinsulinemia, hyperlipidemia, and oxidative stress is still debated. If plasma glucose and/or insulin and/or lipid are some of the most important determinants of oxidative stress in diabetes, then their typical postprandial elevations in diabetes would be expected to favor oxidative stress and LDL oxidation. To test this hypothesis, in type 2 diabetic patients, we evaluated the effects of two different standard meals designed to produce different levels of postprandial hyperglycemia on the plasma oxidative status and LDL oxidation. The meals were administered in randomized order to each of 10 type 2 diabetic patients. Blood samples were collected at baseline and 60 and 120 minutes after the meals. In every sample, plasma levels of glucose, insulin, cholesterol, triglycerides, nonesterified fatty acids (NEFAs), malondialdehyde (MDA), and the total radical-trapping antioxidant parameter (TRAP) were measured. LDL susceptibility to oxidation was evaluated at baseline and after 120 minutes. Plasma glucose, insulin, triglycerides, and MDA increased and NEFAs and TRAP significantly decreased after either meal. The variations in plasma glucose, MDA, and TRAP were significantly greater and LDL was more susceptible to oxidation after the meal that produced a significantly higher degree of hyperglycemia. These results suggest that postprandial hyperglycemia may contribute to oxidative stress in diabetic patients, providing a mechanistic link between hyperglycemia and diabetic vascular disease.

The influence of furosemide on free water clearance.

BACKGROUND: Laboratory measurements of osmolality and electrolyte concentrations are useful as a source of clinical and pathophysiologic information on kidney function. We obtained different conditions of baseline diuresis in 54 rats, which were then treated with furosemide 10 mg/kg. From measurements of plasma (P) and urine (U) osmolality and Na, we calculated the free water clearance (CH2O) and the contributions of Na+ and non-Na(+)-solutes to its changes during diuretic administration. RESULTS: The results show that furosemide abolishes both urine diluting and concentrating ability, by reducing the contribution of non-Na(+)-solutes to Uosm and the formation of CH2O, while the contribution of Na+ to Posm remains unchanged. During furosemide the urines approach isosmoticity irrespective of the baseline Uosm with an asymptomatic function similar to that imposed by osmotic diuresis. It is suggested that the overflow to the concentrating sites of the nephron overwhelms their normal transport capacity independently of their baseline water permeability. The disruption of the transepithelial osmotic gradient caused by the drug impairs the transepithelial osmotic flow, leading to the excretion of isosmotic urines. CONCLUSIONS: The effect of non-Na(+)-solutes in the laboratory measurement of urine constituents can be reduced to that of plasma determination by diluting the urines according to empiric formulas derived from the present data.

Effect of eating on plasma radical-trapping antioxidant activity (TRAP) in patients with cirrhosis.

OBJECTIVES: To ascertain the effects of eating on plasma antioxidant capacity in patients with liver disease. DESIGN AND METHODS: Eighteen cirrhotic patients were compared to 18 age and sex-matched controls. TRAP was measured by a fluorometric assay after a 12 h fast, and 60, 120, and 180 min after the study participants had taken a drink formula food. RESULTS: In the fasting state, TRAP was higher in patients with alcoholic cirrhosis (847+/-39 micromol/L, mean +/- SEM) in comparison to patients with viral cirrhosis (653+/-41) and to controls (758+/-26) (p<0.005). In cirrhotic patients, TRAP did not change in the post-absorptive state. In controls, TRAP decreased progressively, to a value of 719+/-21 (p<0.02), and the AUC of the delta-values of TRAP and of plasma insulin showed an inverse correlation (r = -0.52, p<0.05). CONCLUSIONS: In normal subjects, but not in cirrhotics, TRAP decreases in the post-absorptive state, probably in relationship with the activation of metabolic pathways.

Meal-generated oxidative stress in type 2 diabetic patients.

OBJECTIVE: Free radical production has been reported to be increased in diabetic patients and to be involved in the pathogenesis of diabetic complications. In this study, a standardized meal was administered to 10 type 2 diabetic patients and 10 healthy matched normal subjects to evaluate its effects on plasma oxidative stress generation. RESEARCH DESIGN AND METHODS: In diabetic patients, at baseline and after the meal, plasma malondialdehyde (MDA), vitamin C, protein SH groups, uric acid, vitamin E, and total plasma radical-trapping parameter, which evaluates plasma antioxidant capacity due to known and unknown antioxidants present in the plasma as well as their mutual cooperation, were measured. RESULTS: After the meal, plasma MDA and vitamin C increased, while protein SH groups, uric acid, vitamin E, and total plasma radical-trapping parameter decreased more significantly in the diabetic subjects than in control subjects. CONCLUSIONS: This finding shows that in the absorptive phase, free radicals are produced in diabetic patients. Since plasma glucose, but not insulin, rose significantly more in diabetic subjects than in control subjects, hyperglycemia may play an important role in the generation of postprandial oxidative stress in diabetic patients.

Redox properties of iron in the binding site(s) of F1ATPase from mammalian mitochondria and thermophilic bacterium PS3: a comparative study.

Iron ions in the two iron centers of beef heart mitochondrial F1ATPase, which we have been recently characterized (FEBS Letters 1996, 379, 231-235), exhibit different redox properties. In fact, the ATP-dependent site is able to maintain iron in the redox state of Fe(II) even in the absence of reducing agents, whereas in the nucleotide-independent site iron is oxidized to Fe(III) upon removal of the reductant. Fe(III) ions in the two sites display different reactivity towards H2O2, because only Fe(III) bound in the nucleotide-independent site rapidly reacts with H2O2 thus mediating a 30% enzyme inactivation. Thermophilic bacterium PS3 bears one Fe(III) binding site, which takes up Fe(III) either in the absence or presence of nucleotides and is unable to maintain iron in the redox state of Fe(II) in the absence of ascorbate. Fe(III) bound in thermophilic F1ATPase in a molar ratio 1:1 rapidly reacts with H2O2 mediating a 30% enzyme inactivation. These results support the presence in mitochondrial and thermophilic F1ATPase of a conserved site involved in iron binding and in oxidative inactivation, in which iron exhibits similar redox properties. On the other hand, at variance with thermophilic F1ATPase, the mitochondrial enzyme has the possibility of maintaining one equivalent of Fe(II) in its peculiar ATP-dependent site, besides one equivalent of Fe(III) in the conserved nucleotide-independent site. In this case mitochondrial F1ATPase undergoes a higher inactivation (75%) upon exposure to H2O2. Under all conditions the inactivation is significantly prevented by PBN and DMSO but not by Cu, Zn superoxide dismutase, thus suggesting the formation of OH radicals as mediators of the oxidative damage. No dityrosines, carbonyls or oxidized thiols are formed. In addition, in any cases no protein fragmentation or aggregation is observed upon the treatment with H2O2.

Antioxidant defences are reduced during the oral glucose tolerance test in normal and non-insulin-dependent diabetic subjects.

BACKGROUND: Free radical production has been reported to be increased in patients with diabetes mellitus, and it has been suggested that hyperglycaemia may directly contribute to the generation of oxidative stress. The aim of the present study was to evaluate the effects of an acute increase in glycaemia on plasma antioxidant defences. RESULTS: During the oral glucose tolerance test (OGTT), plasma concentration of protein-bound sulphydryl (SH) groups, vitamin C, vitamin E and uric acid significantly decreased in normal as well as non-insulin-dependent diabetes mellitus (NIDDM) subjects. Total plasma radical-trapping activity, which evaluates plasma antioxidant capacity due to known and unknown antioxidants present in the plasma as well as their mutual co-operation, was also significantly reduced. CONCLUSION: This finding supports the hypothesis that hyperglycaemia may, even acutely, induce an oxidative stress.

Total plasma antioxidant capacity predicts thrombosis-prone status in NIDDM patients.

OBJECTIVE: To explore the hypothesis that a relationship exists between free radical activity and abnormalities in hemostasis in NIDDM. RESEARCH DESIGN AND METHODS: The use of the total radical-trapping antioxidant parameter (TRAP) has very recently been proposed to explore the antioxidant property of a plasma and their mutual cooperation. In the present study, TRAP, vitamin E, vitamin C, vitamin A, uric acid, protein-bound SH (thiol) groups, fibrinogen, prothrombin fragments F1 + 2, and D-dimer have been evaluated in 46 NIDDM patients and 47 healthy matched control subjects. RESULTS: In NIDDM patients, TRAP, vitamin A, SH groups, and uric acid were significantly reduced, whereas the level of vitamin E was significantly increased. Vitamin C was similar in the two groups. Fibrinogen, prothrombin fragment 1 + 2, and D-dimer were increased in diabetic patients. TRAP, but no single other antioxidant, had a strong inverse association with fibrinogen, prothrombin fragment 1 + 2, and D-dimer. CONCLUSIONS: These findings are consistent with the hypothesis that oxidative stress may condition coagulation activation in diabetics. However, the data suggest that it is the total antioxidant capacity rather than any single plasma antioxidant that is the most relevant parameter.

Long-term effects of erythropoietin therapy on fistula stenosis and plasma concentrations of PDGF and MCP-1 in hemodialysis patients.

Among the adverse effects possibly associated with the use of erythropoietin (EPO) in hemodialysis patients is an increased incidence of thrombosis of the vascular access. However, little is known about the effect of EPO on the stenotic lesion in the venous outflow system, which is the leading cause of fistula thrombosis. This study was designed to explore the long-term effects of EPO treatment on progressive fistula stenosis and the plasma concentrations of some potential mediators of neointimal hyperplasia. A cross-sectional and 3-yr prospective, placebo-controlled, pilot study was performed in 30 hemodialysis patients with native arteriovenous fistula. Sixteen patients received EPO and 14 received a placebo. Venous dialysis pressure, urea recirculation, color Doppler sonography, and angiography were used to monitor vascular access patency. Compared with 60 healthy subjects, the hemodialysis patients had elevated plasma levels of platelet-derived growth factor, monocyte chemoattractant protein-1, and interleukin 6, three proteins that might be involved in the neointima formation regulating the proliferation of vascular smooth muscle cells. In addition, these patients had numerous endothelial and hemostatic abnormalities that indicated a thrombophilic state. Eleven patients, six (37.5%) receiving EPO and five (35.7%) taking placebo, developed a progressive stenosis in the venous circuit of the fistula. There was no significant difference in the vascular access, event-free survival over 36 mo between patients receiving EPO therapy and placebo. EPO induced a significant decrease in the plasma values of platelet-derived growth factor and vascular cell adhesion molecule-1 and an increase of monocyte chemoattractant protein-1 concentration. After EPO withdrawal, these parameters returned to pretreatment levels. In conclusion, long-term EPO therapy does not increase the risk of progressive stenosis of native arteriovenous fistula. The use of erythropoietin does not induce any prothrombotic change in hemostatic parameters, and further studies are required to elucidate the theoretically beneficial effects on the plasma concentration of some potential mediators of neointimal formation.

Total radical-trapping antioxidant parameter in NIDDM patients.

OBJECTIVE: The existence of an oxidative stress in diabetes is still debated. This is largely due to the lack of good tools to assay the level of oxidative stress. The use of total radical-trapping antioxidant parameter (TRAP) has recently been proposed to explore the antioxidant property of a plasma sample. TRAP may be either directly measured by a fluorescence-based method (TRAPm) or calculated (TRAPc) by a mathematical formula, taking into account the serum levels of four natural antioxidants: protein-bound SH (thiol) groups, uric acid, vitamin E, and vitamin C. The difference between TRAPm and TRAPc is due to antioxidants, which are still unidentified, and to the possible synergism among the antioxidants. RESEARCH DESIGN AND METHODS: In this study, we evaluated malondialdehyde (MDA), TRAPm, TRAPc, protein-bound SH groups, uric acid, vitamin E, and vitamin C in 40 NIDDM patients and 40 matched normal control subjects. RESULTS: TRAPm and TRAPc were significantly lower in diabetic patients. A good correlation between TRAPm and TRAPc was found in both NIDDM patients (r = 0.68, P < 0.0001) and control subjects (r = 0.74, P < 0.0001). Protein-bound SH groups and uric acid were significantly lower in diabetic subjects, while MDA and vitamin E level were significantly higher. After correction for serum triglycerides (MDA) and cholesterol (vitamin E), MDA lost significance, while vitamin E did not. Vitamin C was not different in the two groups. CONCLUSIONS: These data show decreased TRAP levels in NIDDM patients, suggesting the existence of lower antioxidant defenses in diabetes. The decrease appears to be due to various antioxidants, some of them not yet clearly defined. TRAP may represent a more reliable estimation of serum antioxidant capacity than the measurement of each known antioxidants. The correlation found between TRAPm and TRAPc values suggests that TRAPc, easier to measure than TRAPm, might be adequately reliable for routine assessment of oxidative stress in diabetic patients.

Circulating standard CD44 isoform in patients with liver disease: relationship with other soluble adhesion molecules and evaluation of diagnostic usefulness.

OBJECTIVES: To verify the diagnostic usefulness of soluble CD44 (sCD44) in liver diseases. METHODS: We studied 142 subjects (90 male, 52 female): 14 had acute hepatitis (AH); 45, noncirrhotic chronic liver disease (CLD); 34, cirrhosis; 35 had extrahepatic diseases (EHD); and 14 were healthy controls. sCD44, soluble intercellular adhesion molecule-1 (slCAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1) were measured immunoenzymatically. RESULTS: Patients with AH or cirrhosis had higher sCD44 in comparison to CLD, EHD, and controls (p < 0.01). On univariate analysis, sCD44 was associated with sVCAM-1, sICAM-1, bilirubin, cholinesterase, aspartate aminotransferase, and alkaline phosphatase (p < 0.001). By stepwise discriminant analysis, a set of variables, including sCD44 and sVCAM-1, were entered into a model that allocated correctly 79% of observations (p < 0.0001). However, when adhesion molecules were excluded, the model could still allocate correctly 72% of observations. CONCLUSION: Although sCD44 concentration increases during severe acute or chronic liver disease, its measurement adds little to the clinical information provided by traditional liver biochemistry.

Risk factors for vascular disease and arteriovenous fistula dysfunction in hemodialysis patients.

Vascular access dysfunction is an important cause of morbidity for dialysis patients and a major contributor to hemodialysis cost. Thrombosis is a leading cause of vascular access failure, and usually results from stenotic lesions in the venous outflow system. This study was designed to explore the impact of serum levels of various risk factors for thrombosis and accelerated fibrointimal hyperplasia on progressive stenosis, and the subsequent thrombosis of hemodialysis fistula. A cross-sectional and 2-yr prospective pilot study was performed in 30 nondiabetic hemodialysis patients with primary arteriovenous fistula. Venous dialysis pressure, urea recirculation, color Doppler sonography, and angiography were used to monitor vascular access patency. Eleven patients (37%) developed a progressive stenosis in the venous circuit, which was complicated by thrombosis in three patients. Compared with the patients without fistula dysfunction, these patients had higher serum levels of monocyte chemoattractant protein-1 and interleukin-6, two cytokines that regulate the proliferation of vascular smooth muscle cells, which is the key mechanism in the pathogenesis of fistula stenosis. In addition, they had hyperinsulinemia, hyperlipidemia, and increased plasma levels of two hemostasis-derived risk factors for thrombosis: plasminogen activator inhibitor type 1 and factor VII. Monocyte chemoattractant protein-1, interleukin-6, plasminogen activator inhibitor type 1, factor VII, triglycerides, and the ratios for cholesterol/HDL-cholesterol, apolipoprotein (apo) A-I/ apo C-III, apo A-I/apo B, and glucose/insulin were independent predictors of fistula dysfunction. This study demonstrates the influece of cytokines, hemostasis-derived vascular risk factor, hyperinsullnemia, and abnormallties of lipids and apolipoproteins on primary fistula survival. The assessment of these factors might be useful for the identification of the patients at risk of fistula stenosis and thrombosis.

Increased circulating intercellular adhesion molecule-1 levels in type II diabetic patients: the possible role of metabolic control and oxidative stress.

Blood levels of the circulating form of the integrin intercellular adhesion molecule-1 (ICAM-1), malondialdehyde (MDA), and hemoglobin A1c (HbA1c) were studied at baseline and 3 months after improved metabolic control in 25 type II diabetic patients without signs of macroangiopathy, and were compared with those in 15 matched healthy normal controls. Circulating ICAM-1 and MDA levels were increased in diabetic patients, both at baseline and 3 months later. However, with improving metabolic control HbA1c, circulating ICAM-1, and MDA significantly decreased. A significant correlation between circulating ICAM-1, HbA1c, and MDA was found in diabetic patients at each time. Multiple regression analysis considering circulating ICAM-1 as the dependent variable and HbA1c and MDA as independent variables, showed a significant correlation between the three variable at each time. Similar correlations were found in control subjects. These data show increased levels of circulating ICAM-1 in type II diabetic patients, independent of the presence of macroangiopathy. Moreover, these results suggest that oxidative stress and metabolic control might participate in determining increased circulating ICAM-1 levels in both type II diabetic patients and normal subjects.

Characterization of the binding of Fe(III) to F1ATPase from bovine heart mitochondria.

The binding Fe(III) to F1ATPase purified from beef heart mitochondria has been characterized by chemical analyses and EPR spectroscopy. F1ATPase binds 2 mol of Fe(III)/mol of protein selectively in the presence of saturating concentrations of ATP. In the absence of nucleotides or in the presence of either saturating ADP or limiting ATP concentrations, the enzyme binds 1 equivalent of Fe(III). F1ATPase pretreated with 5'-p- fluorosulfonylbenzoyladenosine, that selectively modifies the non-catalytic sites, binds only 1 mol of Fe(III)/mol of protein in the presence of either saturating ATP or ADP, Fe(III)-loaded F1ATPase containing either 1 or 2 equivalents of Fe(III) show identical EPR signals at g=4.3. The signals are not perturbed by the binding of nucleotides to the enzyme while they are altered by phosphate addition. These results indicate that F1ATPase contains two distinct Fe(III)-binding sites, which differ from nucleotide-binding sites, and that one of these sites is opened up for Fe(III) uptake by conformational changes induced by binding of ATP to the loose non-catalytic site.