Charge selectivity of proteinuria in type I diabetes explored by Ig subclass clearance.

To investigate the role of protein charge in early diabetic proteinuria, the clearance of proteins differing in charge and/or size (anionic and cationic Igs, albumin) was evaluated in 98 insulin-dependent (type I) diabetic patients selected as a representative sample of the 418 patients attending our clinics. Of the patients, 12.9% were microalbuminuric and 4.8% were macroalbuminuric. Anionic and total IgG clearances were significantly increased in 30.6 and 12.2% of patients and were correlated with duration of disease. Anionic IgG4 clearances were increased in patients (9.2%) with normal IgG excretion, suggesting that charge-selectivity impairment is responsible for protein loss. Anionic Ig clearances were also higher in some patients (14.3%) with normal albumin clearance, probably as a result of different glomerular filtration and/or tubular reabsorption. The anionic-cationic IgG clearance ratio tended to increase in parallel with albumin clearance, but once above macroalbuminuric levels, it tended to fall again, indicating the concomitant presence of size-selectivity loss. The anionic IgG clearance and the anionic-cationic IgG ratio, in addition to albumin excretion, may be valuable in assessing early kidney protein charge-selectivity impairment and better characterizing normoalbuminuric patients and those in the preclinical stage of diabetic nephropathy.

Twenty-four-hour noninvasive blood pressure monitoring and pain perception.

Although a hypertension-related hypalgesia has been described, the relation between pain perception and the 24-hour blood pressure trend is still unknown. The ambulatory blood pressure monitoring parameters and dental pain sensitivity were correlated in 67 male subjects. The pulpar test (graded increase of test current of 0 to 0.03 mA) was performed on three healthy teeth, and mean dental pain threshold (occurrence of pulp sensation) and pain tolerance (time when the subjects asked for the test to be stopped) were evaluated. Three groups of subjects with normal (n = 34), intermediate (n = 13), and high (n = 20) blood pressure values were identified according to ambulatory monitoring results. Pain threshold differed among the three groups (P < .02), being higher in the group with highest blood pressure. The groups of hypertensive subjects showed higher pain tolerance than the normotensive group (P < .02). Pain threshold was correlated with 24-hour, diurnal, and nocturnal blood pressure values. Pain tolerance was also related to 24-hour blood pressure and to diurnal and nocturnal diastolic and mean arterial pressure values. Systolic and diastolic blood pressure loads were significantly associated with pain threshold, and diastolic load was also associated with tolerance. The blood pressure variability (SD) did not relate to pain perception. The 24-hour arterial pressure was more closely associated with pain perception than the blood pressure values obtained before the pulpar test. A close correlation between pain perception and 24-hour ambulatory blood pressure was demonstrated.(ABSTRACT TRUNCATED AT 250 WORDS)

Treatment with enalapril modifies the pain perception pattern in hypertensive patients.

The cardiovascular system shares numerous anatomic and functional pathways with the antinociceptive network. The aim of this study was to investigate whether angiotensin-converting enzyme (ACE) inhibitor treatment could affect hypertension-related hypalgesia. Twenty-five untreated hypertensive patients, together with a control group of 14 normotensive subjects, underwent dental pain perception evaluation by means of a pulpar test (graded increase of test current applied to healthy teeth). After the evaluation of the dental pain threshold (occurrence of pulp sensation) and tolerance (time when the subjects asked for the test to be stopped), all the subjects underwent a 24-hour ambulatory blood pressure monitoring. The hypertensive group then was treated with 20 mg/d enalapril, whereas the normotensive subjects remained without any treatment. After a time interval of 6+/-2 months, the dental pain sensitivity was retested in all the subjects, and ambulatory blood pressure was recorded during treatment in the hypertensive patients. At the first assessment, hypertensive patients showed a higher pain threshold than normotensive subjects (P<.001). On retesting of pain sensitivity in hypertensive patients, a significant decrease of both pain threshold and tolerance, leading to their normalization, was observed during treatment (P<.001 and P<.005, respectively), in the presence of reduced 24-hour and office blood pressure values. A slight, though significant, correlation was observed between variations in pain tolerance and baseline blood pressure changes occurring during treatment. During follow-up, the normotensive subjects did not show any significant pain perception or office blood pressure changes. Hypertension-related hypalgesia was confirmed. Mechanisms acting both through lowering of blood pressure and specific pharmacodynamic properties may account for the normalization of pain sensitivity observed in hypertensive patients during treatment with ACE inhibitors.

Effects of prolonged picotamide therapy on platelet activity in patients with peripheral arterial disease.

An open study was carried out in 14 patients with peripheral arterial disease to investigate the effects of prolonged therapy with picotamide on platelet activity. Patients received daily oral doses of 900 mg picotamide for 1 month, 600 mg per day during the second month and 300 mg per day from the third to the sixth month of the study. Measurements were made before and during therapy of blood coagulation parameters and factors influencing platelet function, i.e. plasma beta-thromboglobulin and serum thromboxane B2. The results showed that there were no significant variations in platelet count, prothrombin time, partially activated thromboplastin time, presence and amount of fibrinogen in blood, and antithrombin III. Examination for fibrinogen degradation products was constantly negative and unaltered during therapy. Although plasma beta-thromboglobulin values did not vary significantly, there was a significant and progressive reduction throughout treatment in serum levels of thromboxane B2.

Role of advanced glycation end-products (AGE) in late diabetic complications.

To evaluate accumulation of advanced glycation end-products (AGE) in diabetes and its possible correlation with late diabetic complications, AGE levels were measured by spectrofluorimetry in eye lens and sciatic nerve proteins and isolated tail tendon collagen of rats with experimental diabetes of 3- and 6-month duration. The values obtained were compared to those from age-matched control rats and correlated with cataract presence and somatosensory evoked potential (SEP) alterations. Diabetic animals had increased AGE levels in all tissues at both times; cataract developed in 29% of diabetic rats at 3 months and in 57% at 6 months; SEP conduction velocity was reduced in diabetic animals both at 3 (54.5 +/- 1.8 S.E.M. m/s vs. 73.9 +/- 1.0, P < 0.0001) and 6 months (59.5 +/- 1.4 vs. 71.5 +/- 1.6, P < 0.0001) from diabetes induction. No eye lens AGE level differences were observed when cataract presence was considered. Interestingly, in diabetic rats, increased sciatic nerve AGE levels were associated with reduced SEP. These data show that: (1) AGE levels are increased as early as 3 months from development of hyperglycemia; (2) other factors, in addition to an enhanced rate of fluorescent AGE formation, might play important roles in the pathogenesis of diabetic cataract; (3) increased peripheral nerve AGE levels are associated with SEP alterations.

Benign edematous polysynovitis in the elderly (RS3PE syndrome).

The Authors provide an update on benign edematous polysynovitis in the elderly and propose clinical and laboratory criteria for a correct diagnosis. They also propose the use of the term "polysynovitis" rather than polyarthritis, as they think it describes the histopathological findings of the disease better. Finally, they attempt to correctly distinguish RS3PE syndrome from polymyalgia rheumatica, rheumatoid arthritis and chondrocalcinosis.

A charge selectivity impairment in protein permselectivity is present in type 2 diabetes.

A possible loss in kidney charge permselectivity of proteins before any manifestation of nephropathy has been sought in type 2 (non-insulin-dependent) diabetes by assessing the clearances of proteins differing in charge and/or size (anionic and cationic immunoglobulins, albumin). Eighty-five consecutive outpatients with type 2 diabetes were studied and compared with 101 normal subjects. Of the patients, 14.1% were microalbuminuric and 2.3% macroalbuminuric. A significant increase in protein clearances was observed in diabetic patients in comparison with normal subjects: the median of albumin clearance was 0.09 ml/min, interquartile range (IR) 0.04-0.31 (P < 0.01 vs normals); that of anionic immunoglobulins (IgG4) 0.02 ml/min, IR 0.04-0.05 (P < 0.005 vs normals); and that of neutral/cationic immunoglobulins (IgG) 0.13 ml/min, IR 0.07-0.19 (P < 0.01 vs normals). The anionic/cationic immunoglobulin ratio median was 0.22, IR 0.11-0.43, and exceeded the upper limit of normal values in 29.4% of all patients. IgG4 clearance was positively correlated with albumin clearance (r = 0.72) and with IgG clearance (r = 0.98). Nevertheless anionic immunoglobulin clearance was increased in a number of patients (17.3%) with normal IgG excretion and even in patients (15.1%) with normal albumin clearance. Clearances of IgG4 and IgG, but not that of albumin, were correlated with the duration of diabetes. Thus, an increased anionic/cationic IgG ratio in type 2 diabetes highlights a charge selectivity defect in protein permselectivity; this selective proteinuria may reflect more accurately than does microalbuminuria an early kidney abnormality in this form of diabetes.

Enhanced nonenzymatic glycation of eye lens proteins in experimental diabetes mellitus: an approach for the study of protein alterations as mediators of normal aging phenomena.

The levels of advanced nonenzymatic glycation endproducts (ACE) were investigated by spectrofluorimetry in eye lens proteins obtained from rats with experimental diabetes of 3 and 6 months duration and from normal age-matched control rats. Diabetic animals showed higher AGE levels at both times studied. However the older control animals showed protein ACE levels comparable to those of the experimental 3 months diabetic group. These data suggest that a pathological phenomenon such as enhanced nonenzymatic glycation, associated to diabetic hyperglycemia, can be considered as a process leading to an accelerated aging of proteins. Thus experimental diabetes mellitus may be used as a model to investigate physiological protein senescence.

Hypertension in a group of centenarians.

The aim of the present study was to evaluate the frequency of hypertension in a group of extremely old persons: 73 centenarians resident in Calabria were studied, aged 100-110 years, (mean age 102.95 +/- 2.0), 54 women (73.9%) and 19 men (26.1%), in the period January 1st and April 30th, 1994. All the centenarians were visited at their homes. Hypertensive centenarians were 14 (19.1%), women 12 (85.7%) and men 2 (14.3%). Even if blood pressure progressively increases with age, we have not found it in centenarians. The lesser frequency of hypertension in centenarians certainly depends on genetic and constitutional factors, but also their way of life and alimentary habits (decreased sodium intake, increase of calcium and potassium intake), as we have proven in a recent work, could be determinant. Moreover, the presence of hypertensive centenarians might mean that hypertension does not prevent to reach an age by far above the average, if it is the only risk factor.

[Cerebral hypoperfusion symptoms in elderly subjects with hyperkinetic and/or hypokinetic arrhythmia. Study of institutionalized and non- institutionalized patients]. / Sintomatologia da ipoperfusione cerebrale nei soggetti anziani portatori di aritmie ipercinetiche e/o ipocinetiche. Indagine su pazienti istituzionalizzati e non.

BACKGROUND: We evaluated the symptomatology caused by cerebral hypoperfusion in a group of over-65 year old hospitalized and non-patients, with hyperkinetic and hypokinetic arrhythmias. METHODS: 2441 clinical records of hospitalized and ambulatory patients at the unit of Cardiology, "Pugliese-Ciaccio" Hospital of Catanzaro between January 1st 1991 and March 31st 1995 were examined. The clinical records of those patients who had showed anamnestic episodes of syncope, lipothymia and dizziness were selected. The selected sample was made of 36 hospitalized patients and 36 ambulatory patients. The Holter-ECGs of these patients were examined. RESULTS: Six episodes of syncope (16.7%) were found in the hospitalized patients and 4 in the ambulatory patients (11.1%). Ten (27.8%) and 8 (22.2%) episodes of lipothymia, were found in the hospitalized and ambulatory patients respectively. Dizziness was found in 20 (55.5%) hospitalized and in 24 (66.6%) ambulatory patients. In all the patients the symptoms appeared during the recording and were linked to hyperkinetic arrhythmias in 22 (61.1%) hospitalized patients and in 25 (69.4%) ambulatory patients and to hypokinetic arrhythmias in 14 (39.9%) and 11 (30.5%) hospitalized and ambulatory patients. CONCLUSIONS: The present study pointed out that patients with hyperkinetic arrhythmias (both hospitalized and ambulatory) show symptoms of cerebral hypoperfusion more frequently than those with hyperkinetic arrhythmias.

Elevated cerebral blood volume contributes to increased FLAIR signal in the cerebral sulci of propofol-sedated children.

BACKGROUND AND PURPOSE: Hyperintense FLAIR signal in the cerebral sulci of anesthetized children is attributed to supplemental oxygen (fraction of inspired oxygen) but resembles FLAIR hypersignal associated with perfusion abnormalities in Moyamoya disease and carotid stenosis. We investigated whether cerebral perfusion, known to be altered by anesthesia, contributes to diffuse signal intensity in sulci in children and explored the relative contributions of supplemental oxygen, cerebral perfusion, and anesthesia to signal intensity in sulci. MATERIALS AND METHODS: Supraventricular signal intensity in sulci on pre- and postcontrast T2 FLAIR images of 24 propofol-sedated children (6.20 ± 3.28 years) breathing supplemental oxygen and 18 nonsedated children (14.28 ± 2.08 years) breathing room air was graded from 0 to 3. The Spearman correlation of signal intensity in sulci with the fraction of inspired oxygen and age in 42 subjects, and with dynamic susceptibility contrast measures of cortical CBF, CBV, and MTT available in 25 subjects, were evaluated overall and compared between subgroups. Factors most influential on signal intensity in sulci were identified by stepwise logistic regression. RESULTS: CBV was more influential on noncontrast FLAIR signal intensity in sulci than the fraction of inspired oxygen or age in propofol-sedated children (CBV: r = 0.612, P = .026; fraction of inspired oxygen: r = -0.418, P = .042; age: r = 0.523, P = .009) and overall (CBV: r = 0.671, P = .0002; fraction of inspired oxygen: r = 0.442, P = .003; age: r = -0.374, P = .015). MTT (CBV/CBF) was influential in the overall cohort (r = 0.461, P = .020). Signal intensity in sulci increased with contrast in 45% of subjects, decreased in none, and was greater (P < .0001) in younger propofol-sedated subjects, in whom the signal intensity in sulci increased with age postcontrast (r = .600, P = .002). CONCLUSIONS: Elevated cortical CBV appears to contribute to increased signal intensity in sulci on noncontrast FLAIR in propofol-sedated children. The effects of propofol on age-related cerebral perfusion and vascular permeability may play a role.

Ocular haemodynamics in some subgroups of normal pressure glaucoma.

The authors studied, by means of Color Doppler Imaging, a group of Normal Pressure Glaucoma subjects They found some haemodynamic abnormalities in them which differed in the various subgroups. It would seem that, for each NPG subgroup, there are specific physiopathological and clinical features.

D-lysine effectively decreases the non-enzymic glycation of proteins in vitro.

Excessive non-enzymic glycation of proteins alters their physicochemical properties, with possible pathological effects. We investigated the in vitro inhibition of protein glycation by D-lysine--an isomer not incorporated into mammalian proteins but possessing the same chemical characteristics as L-lysine. Glucose incorporation was studied as follows: (a) human albumin, IgG, collagen, and isolated glomerular basement membrane were incubated for 20 days with D-glucose (5.0, 10.0, and 20.0 mmol/L) in the presence of D-lysine at 1/10 the sugar concentration; (b) albumin was incubated in similar glucose concentrations but with a constant amount (2.0 mmol/L) of D-lysine; (c) albumin and IgG were incubated for 10 days in buffer containing glucose (10 mmol/L) and increasing concentrations of D-lysine (0.25, 0.5, 1.0, 2.0, and 4.0 mmol/L); (d) inhibition specificity was tested by treating albumin as in c but with glycerol present rather than D-lysine. In addition, we measured ketoamine after incubating albumin (50 g/L) in 10 mmol/L glucose for 10 days in the presence of D-lysine (0.25, 0.5, 1.0, and 2.0 mmol/L). The results show that (a) the amount of glucose bound to the four proteins was significantly (P less than 0.05) decreased in the presence of D-lysine at the higher concentrations of glucose; (b) the lower the glucose concentration, the higher was the inhibitory effect of D-lysine; (c) the inhibition of glucose incorporation into proteins correlated directly with the concentration of D-lysine; (d) no inhibition was observed with glycerol. Ketoamine decreased with increase in D-lysine (P less than 0.01). The effective diminution of non-enzymatic glycation by D-lysine highlights its potential use in vivo.

Formation and ways of detecting advanced glycation end-products in isolated human glomerular basement membrane and human serum albumin nonenzymatically glycated in vitro.

The formation of advanced glycation end-products (AGE) was investigated in samples of isolated human glomerular basement membrane (hGBM) and human serum albumin (hSA) which had been nonenzymatically glycated in vitro. In order to measure AGE, two methods which differ in principle--the standard spectrofluorescence technique and the spectrophotometric diazonium salt reaction--have been used and compared. Samples of finely homogenized hGBM and hSA were incubated for 10 days in buffer containing 500 mmol/L (9 x 10(3) mg%) and 100 mmol/L (1.8 X 10(3) mg%) D-glucose respectively. At the end of the incubation period, the ambient glucose was removed and the samples were incubated for a further 10 days in glucose-free buffer. During this time, loosely bound sugar was released into the buffer; at the end of the incubation, the emission fluorescence at 440 nm (following continuous excitation at 370 nm) and the absorbance at 492 nm of the glycated hGBM and hSA samples were measured and found to be significantly increased by comparison with native samples (1-way ANOVA: p less than 0.05 with both techniques). Comparison of the two techniques used for AGE detection showed a positive linear correlation (Pearson's correlation coefficient r = 0.714; n = 8; p = 0.02). The released glucose probably originates from reversal of the Schiff base (the first and reversible step of the nonenzymatic glycation reaction), whereas fluorescence and photometric findings prove the presence of stable AGE on both hGBM and hSA. It is concluded that AGE can indeed be formed and detected by two different methods in hGBM (and hSA) subjected to nonenzymatic glycation in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)

Anionic versus cationic immunoglobulin clearance in normal subjects: a novel approach to the evaluation of charge permselectivity.

The excretion of proteins differing in charge (the different immunoglobulin subclasses) and/or size (albumin, immunoglobulins) were investigated in normal subjects in a number of physiological conditions aiming at the evaluation of renal charge permselectivity. In 101 randomly selected normal subjects the urinary excretion rates of albumin, IgG4 (anionic proteins) and of total IgG (mostly cationic) were evaluated in basal conditions; the protein/creatinine urinary ratio and protein clearances were assessed in part of them. In addition, the intra- and interday variations of protein excretion were evaluated. Protein clearances were measured in a sample group after standardized physical exercise, after an amino acid load, and in orthostatism. Albumin, IgG4 and IgG were assayed using sensitive methods developed in our laboratories. The excretion rate values of albumin, IgG4 and total IgG (median, interquartile range) were 4.36 micrograms/min, (2.58-6.59), 4.25 ng/min (2.6-7.6), and 1.47 micrograms/min (0.85-2.44), respectively. The clearances of the three proteins (mean +/- SD) were 0.13 +/- 0.07, 0.017 +/- 0.012 and 0.14 +/- 0.08 ml/min x 10(-3), respectively. The IgG4/IgG ratio averaged 0.1 and was always below 0.25. Protein excretion rates showed a noticeable variation during the day and from day to day. Physical exercise, the change of posture and the amino acid load significantly increased proteinuria but did not significantly modify the anionic/cationic immunoglobulin ratio. Thus, the anionic/cationic immunoglobulin ratio of about one tenth, substantially stable during dynamic tests, in normal subjects may be considered an index of physiological renal protein charge permselectivity.

Reduction of advanced glycation end-product (AGE) levels in nervous tissue proteins of diabetic Lewis rats following islet transplants is related to different durations of poor metabolic control.

Advanced glycation end-products (AGEs) are irreversible compounds which, by abnormally accumulating over proteins as a consequence of diabetic hyperglycaemia, can damage tissues and thus contribute to the pathogenesis of diabetic complications. This study was performed to evaluate whether restoration of euglycaemia by islet transplantation modifies AGE accumulation in central and peripheral nervous tissue proteins and, as a comparison, in proteins from a non-nervous tissue. Two groups of streptozotocin diabetic inbred Lewis rats with 4 (T1) or 8 (T2) months disease duration were grafted into the liver via the portal vein with 1200-1500 islets freshly isolated from normal Lewis rats. Transplanted rats, age-matched control and diabetic rats studied in parallel, were followed for a further 4-month period. At study conclusion, glycaemia, glycated haemoglobin and body weight were measured in all animals, and an oral glucose tolerance test (OGTT) performed in transplanted rats. AGE levels in cerebral cortex, spinal cord, sciatic nerve proteins and tail tendon collagen were measured by enzyme-linked immunosorbent assay (ELISA). Transplanted animal OGTTs were within normal limits, as were glycaemia and glycated haemoglobin. Diabetic animal AGEs were significantly higher than those of control animals. Protein AGE values were reduced in many transplanted animals compared to diabetic animals, reaching statistical significance in spinal cord (P < 0.05), sciatic nerve (P < 0.02) and tail tendon collagen (P < 0.05) of T1 animals. Thus, return to euglycaemia following islet transplantation after 4 months of diabetes with poor metabolic control reduces AGE accumulation rate in the protein fractions of the mixed and purely peripheral nervous tissues (spinal cord and sciatic nerve, respectively). However, after a double duration of bad metabolic control, a statistically significant AGE reduction has not been achieved in any of the tissues, suggesting the importance of an early therapeutic intervention to prevent the possibly pathological accumulation of AGEs in nervous and other proteins.

Characteristics of proteinuria in experimental diabetes mellitus.

An impairment of protein charge selectivity has been invoked to explain the initial anionic proteinuria in diabetic nephropathy. The aims of this work were to investigate charge and size protein perm-selectivity abnormalities in experimental diabetes and to monitor these changes over time after diabetes induction. Diabetes was induced in 56 Sprague-Dawley male rats by streptozotocin; the control group was represented by 38 normal rats. Blood glucose, body weight, urine volumes, and proteinuria in 24-h urine collections were evaluated at 3, 6, 9, and 12 months of diabetes. The Bradford method and mono- and bidimensional gel electrophoresis were used to determine and characterize proteinuria. Body weight increase was lower (P < 0.05, P < 0.0001, P < 0.05 at 3, 6, and 12 months, respectively), urine volumes were greater (P < 0.001, P < 0.005, P < 0.05 at 6, 9, and 12 months, respectively) and the proteinuria was significantly increased (P < 0.05 at 3 months, P < 0.001 at 6 months, P < 0.01 at 9 months, and P < 0.05 at 12 months) in diabetic rats compared with the control group. When the charge and the size of urine proteins were considered, small (30 kDa) and anionic proteins were found to be mainly excreted in diabetic rats, at 3 months of the disease; at 6 months, higher amounts of albumin and cationic proteins with higher molecular weight (50 kDa) were also found in the urine; at 9 and 12 months the changes previously described were associated with an excretion of proteins weighing about 75 kDa.(ABSTRACT TRUNCATED AT 250 WORDS)

D-lysine reduces the non-enzymatic glycation of proteins in experimental diabetes mellitus in rats.

D-Lysine, the non-physiological isomer of L-lysine, can competitively reduce protein non-enzymatic glycation in vitro. To study the effect of D-lysine in vivo, 6-8-week old Sprague-Dawley rats with streptozotocin-induced diabetes mellitus were treated from diagnosis for 45 days with two daily subcutaneous injections of D-lysine (0.5 g.ml-1.day-1). Another group of diabetic rats was only injected with equal volumes of physiological saline (0.9% NaCl). Glycated haemoglobin was measured by ion exchange chromatography, and glycated serum and lens proteins by boronate affinity gel chromatography. Serum and urinary creatinine concentrations were evaluated by the alkaline-picrate reaction. Urinary lysine concentrations at mid- and end-study were evaluated by cation exchange chromatography. Blood glucose concentrations, serum creatinine levels and creatinine clearances, measured at the end of the study, were similar in both diabetic groups (> 22.0 mmol/l, < or = 106 mumol/l and approximately 0.02 ml/s, respectively). Urinary lysine concentration in D-lysine-treated diabetic animals was more than 50-fold higher than in placebo-treated diabetic rats. In D-lysine-treated vs placebo-treated diabetic animals, a statistically significant reduction was found in the levels of glycated haemoglobin (stable HbA1; mean +/- SD = 3.00 +/- 0.74% vs 4.02 +/- 0.46%, p < 0.05; labile HbA1 = 3.92 +/- 0.89% vs 5.84 +/- 0.61%, p < 0.005), glycated serum proteins (1.40 +/- 0.47% vs 2.52 +/- 1.15%, p < 0.05) and glycated lens proteins (4.90 +/- 0.96% vs 5.98 +/- 0.65%, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Antineutrophil cytoplasmic antibodies are present in long standing type 1 diabetics but do not correlate with selective proteinuria.

Antineutrophil cytoplasmic antibodies (ANCA) are present in systemic vasculitis with or without renal involvement and in inflammatory bowel diseases, conditions which share damage in proteoglycan content of basal membrane. In diabetes, there is a reduction in proteoglycans in the kidney basal membrane, responsible for the decrease in fixed anionic charges and, consequently, for the prevalent anionic proteinuria (albumin, IgG4) even in the early preclinical stage of nephropathy. The aims of this study were to search for the presence of ANCA in long-standing type 1 diabetic patients and to evaluate possible correlations with size- and/or charge-selective proteinuria. Twenty-two type 1 diabetic patients (duration of diabetes 24 years, range 9-30) selected and grouped according to albumin excretion rate values, were studied together with 21 age and sex comparable normal subjects. ANCA, albumin excretion rate, and the clearances of albumin, of prevalently cationic total IgG (IgG) and of anionic IgG4 were evaluated. ANCA were measured using ELISA and indirect immunofluorescence methods; albumin, IgG and IgG4 were tested with RIA or ELISA methods developed in our laboratory. ANCA were found in five patients, three of whom showed proteinuria. 33.3% and 18.2% of patients with normal IgG and albumin clearances respectively had elevated IgG4 clearance. This study shows for the first time the presence of ANCA in long-standing type 1 diabetic patients and confirms a prevalent anionic protein excretion in these patients, but does not show a correlation between the presence of ANCA and proteinuria, even if the presence of ANCA in diseases sharing alterations in proteoglycan content of vascular basal membrane is noteworthy.