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Biomedical subjects

U Di Mario

Publications and source records attributed to U Di Mario.

At least 109 records · Page 6Linked to original sources
PubMed1989

Anti-goat immunoglobulin antibodies in diabetic children at diagnosis and follow-up: comparison with islet cell antibodies and other autoantibodies.

The presence of antibodies reacting with human as well as animal immunoglobulins in sera from recent onset Type I diabetic patients has been recently demonstrated by some of our group. In the present study, the occurrence of these antibodies has been evaluated in sera from 19 Type I diabetic patients, at diagnosis and at follow-up within three years, and from 26 normal subjects, and has also been compared with the presence of islet cell antibodies and other organ-specific autoantibodies. A solid-phase radioimmunoassay has been used: serum was incubated in goat immunoglobulin-coated wells and the binding of 125-I-anti-human immunoglobulin antibodies was evaluated. Anti-goat immunoglobulin antibodies were above the 90th percentile of normal values in all diabetic patients at diagnosis (median, interquartile range, in micrograms 125I-antibody bound/1 serum: 83, 77.5-88, versus 51.5, 44.5-62 in normal subjects, P less than 0.001) and significantly declined with time after diagnosis (P less than 0.001). Islet cell antibodies were present in 79% of patients at diagnosis, whereas at least one other auto-antibody was found in 21% of patients. In the follow-up study the decline in anti-goat immunoglobulin antibody levels was different from that of islet cell antibody positivity. A circulating immunoglobulin reacting with other immunoglobulins is thus present in the early stages of Type I diabetes and may well play a part in the complex immunopathogenetic interactions.

Animals↗
PubMed1989

Ganglioside expression in human pancreatic islets.

Recent biochemical studies have shown that the cytoplasmic islet cell-antibody autoantigen has properties of a monosialoganglioside (GM). To characterize islet glycolipids and ascertain whether islets express unique gangliosides, we determined the pattern of ganglioside expression in whole human pancreas and isolated human islets using high-performance liquid chromatography (HPLC) and high-performance thin-layer chromatography (HPTLC). The major gangliosides detected in glycolipid extracts of whole human pancreas were GM3, GD3 (disialoganglioside), and in a lesser amount, a GD1a-comigrating ganglioside. In contrast to whole human pancreas, isolated human islets were found to predominantly express GM3, an acidic glycolipid comigrating with GM2, and a ganglioside with mobility between GM2 and GM1 by both HPLC and HPTLC. Quantitation of the major ganglioside UV peaks seen on HPLC gave the following results. In whole pancreas, GM3 represented 66.7% of total gangliosides detected; an asialoglycolipid comigrating with GM2, 2.0%; a ganglioside migrating between GM2 and GM1, 2.6%; GD3, 22.6%; and a GD1a-comigrating ganglioside, 6.1%. In isolated islets, these components were found at the following levels: GM3, 14.9%; GM2-comigrating glycolipid, 74.2%; a ganglioside migrating between GM2 and GM1, 9.8%; GD3, 1.1%; and the GD1a-comigrating ganglioside, not detectable.

Chromatography, High Pressure Liquid↗
PubMed1989

Urinary IgG4: an additional parameter in characterizing patients with incipient diabetic nephropathy.

In the natural history of diabetic nephropathy there is a progressive impairment of protein permselectivity. The early increased excretion of anionic proteins may be explained by the initial loss of charge selectivity of the filtration filter. In comparison to other immunoglobulin subclasses, IgG4 has the same molecular weight but an acid isoelectric point: its possible selective urinary elimination could indicate a charge selectivity impairment in the preclinical stage of diabetic nephropathy. To verify this hypothesis, 53 Type 1 diabetic patients, grouped according to their albumin excretion rate (AER) (23 showed an AER less than 35 micrograms/min, Group I; 19 between 35-200 micrograms/min, Group II; 11 an AER greater than 200 micrograms/min, Group III), and 20 normal subjects were tested for urinary IgG4, total IgG, and other nephrological and metabolic parameters. Urinary IgG4 and IgG were detected with solid phase methods (ELISA and RIA respectively) developed in our laboratory. Urinary total IgG values were significantly higher in Group III in comparison with Group I and II and with normal subjects. Urinary IgG4 values were significantly increased in Group III, as well as in Group II, in comparison with Group I and normal controls. IgG4/IgG ratio values were significantly increased in both Groups II and III in comparison with Group I and control subjects. Whereas IgG values were within the normal range in Group II, IgG4 values were clearly elevated, thus demonstrating a selective elimination of this acid, medium-sized protein. Urinary IgG4 could be an additional parameter to characterize more precisely and subgroup microalbuminuric patients.

Adolescent↗
PubMed1989

A longitudinal study of multimodal evoked potentials in diabetes mellitus.

Abnormal findings in visual (VEP), brainstem auditory (BAEP) and somatosensory (SEP) evoked potentials at early stages of Type 1 and Type 2 diabetes have recently been reported by our group. Our aim here was to perform a longitudinal study in diabetic patients at an early stage of the disease using a combined evoked potential analysis in order to evaluate the variation of neurological abnormalities over time. Nine Type 1 and 12 Type 2 diabetic patients were examined and a second recording was carried out after a mean interval of 15.7 months +/- 6.2 SD. VEP, BAEP and SEP were measured in all patients. At the first recording electrophysiological abnormalities, present in both Type 1 and Type 2 diabetes were more evident when a multimodal evaluation was used (44.4% and 66.7% respectively). The follow-up study showed that overall neurological abnormalities persisted in all those patients who had previously presented pathological values. Whereas the number of patients with pathological values remained unmodified, a tendency to progression, namely the number of nervous levels with electrophysiological abnormalities, was observed. Thus, our study confirms the appearance of anatomofunctional disorders in the central nervous system in short-term diabetes, shows the persistence of neurological impairment in such patients and reveals a progressive segmental involvement at different nervous levels.

Acoustic Stimulation↗
PubMed1988

Quantitative immunological differences between newly diagnosed Graves' disease patients and relapsed patients.

Class 2-positive T cells, T-cell and mononuclear cell subsets, thyrotropin receptor antibodies (TRAb) and immune complexes were evaluated in 34 newly diagnosed Graves' patients and in 13 relapsed patients before a cycle of specific medical treatment. Class II-positive T lymphocytes were detected by monoclonal antibodies against different epitopes of class II antigens, whereas 4F2-positive cells were detected by 4F2 monoclonal antibody. 4F2-positive cells were statistically increased in newly diagnosed Graves' patients compared to relapsed patients (p less than 0.05). An increased percentage of class II activated T cells, detected by monoclonal antibodies L243, was found in newly diagnosed patients in comparison with relapsed subjects (p less than 0.025). Newly diagnosed Graves' patients showed a significant decrease in the ratio suppressor/cytotoxic T cells in comparison with normal control subjects but not with relapsed patients. Ninety-one % of newly diagnosed Graves' patients showed a high TRAb value, whereas only 69% of relapsed patients showed increased values (p less than 0.025). No difference was observed in the immune complex positivity between newly diagnosed Graves' patients and relapsed subjects. In conclusion, both humoral and cellular immune differences were found in relapsed patients vs newly diagnosed Graves' patients. The immunological abnormalities are quantitatively more pronounced in the latter group.

Adolescent↗
PubMed1988

A prozone phenomenon interferes in islet cell antibody detection: direct comparison of two methods in subjects at risk of diabetes and in insulin dependent diabetics at onset.

A recent international workshop documented marked interlaboratory variation in end point titers of standard islet cell antibody (ICA) positive sera. End titers were lower using a modified assay which utilizes fluorescein labeled protein A (ICA-pA) rather than fluoresceinated anti-IgG (ICA-IgG) to detect antibody binding to islets. In this study we sought to compare directly two ICA assays with respect to future development of IDDM. Sera were obtained from 26 prospectively evaluated high risk subjects identified by family screening or history of transient hyperglycemia and 12 normal controls. As expected, end point titers for ICA positive sera were 10 times greater using the ICA-IgG assay than with the ICA-pA assay. However, despite higher end point titers, the ICA-IgG assay failed to detect more 'prediabetics' and showed a prozone effect. Fourteen subjects were positive at a 1:2 dilution using the ICA-pA assay. Only 10 of these 14 were positive at a 1:2 dilution using the ICA-IgG assay but all became positive at greater sera dilutions. No normal controls were positive using either assay. A similar prozone was observed with anti-islet monoclonal antibodies A2B5 and 4F2. Sera from 14 long-standing IDDM patients (where titers of ICA may have decreased relative to time of onset of diabetes) which were negative using ICA-pA were also assayed using ICA-IgG. Five sera positive for ICA-IgG but negative for ICA-pA were identified. In addition two sera in which a prozone effect was seen with ICA-pA were identified.(ABSTRACT TRUNCATED AT 250 WORDS)

Agglutination Tests↗
PubMed1988

A novel neuroendocrine cell surface glycoprotein: identification, isolation, and initial characterization.

Murine monoclonal antibodies (MAbs) HISL-5, -9, and -14, generated after immunization of mice with human pancreatic islet cell preparations, recognize a differentiation antigen expressed by the pancreatic islet cells. These MAbs react strongly with all endocrine cell subtypes of human pancreatic islets, but minimally if at all with the exocrine acinar cells, vascular cells, and stromal connective tissue cells of the pancreas. The antigen is located on the cell surface (plasma membranes), as indicated by immunofluorescence staining of viable cell preparations. Besides the pancreatic islets, HISL-5, -9, and -14 antigenic determinants are also expressed by thyroid follicular cells, parathyroid chief cells, and anterior pituitary cells, other commonly involved targets in organ-specific autoimmune disorders. Preliminary biochemical findings indicated that the MAb-defined epitope(s) is trypsin sensitive and resistant to periodate oxidation and exposure to chloroform-methanol. Further biochemical studies, including single step MAb immunoaffinity chromatographic purification, indicate that the antigen recognized by the MAbs HISL-5, -9, and -14 is a 100 K glycoprotein.

Animals↗
PubMed1988

Circulating anti-immunoglobulin antibodies in recent-onset type I diabetic patients.

Human sera from 51 recent-onset insulin-dependent (type I) diabetic patients and 47 unrelated control subjects were screened for the possible presence of circulating factors reacting with several anti-pancreatic islet monoclonal antibodies (MoAb.ISL) in solid-phase radioimmunoassay methods (the original goal being the detection of anti-idiotypic islet cell antibodies and/or specific islet cell antigen-bearing immune complexes). MoAbs from the parental myeloma cell line and purified immunoglobulins (Igs) from different animal species were controls. Type I diabetic sera showed significantly increased binding to MoAb.ISL-coated wells compared with normal subjects (P less than .001). However, the same sera also tended to show a higher binding to the control (non-islet-related) MoAb. Sera from type I diabetic patients also reacted with horse, bovine, pig, rabbit, and goat IgG. Displacement of the binding has been obtained by F(ab')2 and/or Fc fragments of IgG. Evidence has been obtained regarding a similar reaction with human IgM. All the sera were negative when tested for rheumatoid factor by nephelometry. The circulating antibodies described have been proven to be different from islet cell autoantibodies. An anti-Ig antibody is thus present in the sera of recent-onset diabetic patients and represents an additional immunological phenomenon with possible physiopathological and clinical significance.

Adult↗
PubMed1988

Renal hemodynamics and urinary excretion of 6-keto-prostaglandin F1 alpha and thromboxane B2 in newly diagnosed type I diabetic patients.

We have studied the functional importance of renal eicosanoids in renal hemodynamics of seven newly diagnosed insulin-dependent diabetes mellitus (IDDM) patients by treatment with two structurally unrelated inhibitors of cyclooxygenase (i.e., piroxicam and sulindac). Glomerular filtration rate (GFR), renal plasma flow (RPF), daily urinary excretion of 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha, the stable hydrolysis product of prostacyclin), and thromboxane B2 (TXB2, the stable hydrolysis product of thromboxane A2) were measured before, during, and after piroxicam (all patients) or sulindac (3 patients) treatment. Urinary excretion of 6-keto-PGF1 alpha was significantly increased (P less than .01) in diabetic patients compared with seven healthy subjects, whereas urinary excretion of TXB2 was unchanged. The baseline value of GFR was significantly (P less than .01) higher in diabetic compared with normal volunteers, whereas baseline RPF was comparable in both groups. Piroxicam (20 mg/day) reduced urinary excretion of 6-keto-PGF1 alpha and TXB2 by 65.7 +/- 26 and 64.6 +/- 33%, respectively. These biochemical changes were temporally associated with the approximately 19% decrease in GFR (P less than .01). A week after discontinuation of the drug, GFR and urinary excretion of 6-keto-PGF1 alpha were still significantly (P less than .05) reduced, whereas urinary excretion of TXB2 returned to control values. In contrast, urinary excretion of eicosanoids and renal function were not affected by sulindac (0.4 g/day) treatment. No functional changes were detected in healthy subjects despite a similar suppression of renal cyclooxygenase activity when they were treated with piroxicam.(ABSTRACT TRUNCATED AT 250 WORDS)

6-Ketoprostaglandin F1 alpha↗
PubMed1988

Early detection of neurological involvement in IDDM and NIDDM. Multimodal evoked potentials versus metabolic control.

Clarification of the extent and mechanisms of damage to the central nervous system in diabetes is a frontier of current neurological research. Our aim was to obtain ample electrophysiological documentation of possible neurological abnormalities in both insulin-dependent (IDDM) and non-insulin-dependent (NIDDM) diabetic patients with a short duration of disease and without overt complications, taking into account metabolic control. Group 1 comprised 11 IDDM patients, and group 2 included 14 NIDDM patients treated with diet alone; the duration of disease was less than 4 yr, and no concomitant clinical complications were present. Age- and sex-matched normal subjects formed groups 3 and 4. Pattern visual evoked potentials (VEP), brain stem auditory evoked potentials (BAEP), and somatosensory evoked potentials (SEP; after the stimulation of both median and tibial nerves) were recorded in all subjects, and metabolic control was evaluated in terms of glycemia and glycosylated hemoglobin. In group 1, significant abnormalities were found in the latency values of VEP, median SEP, and tibial SEP compared with control subjects. Similar latency abnormalities were shown in group 2 for VEP, median SEP, and tibial SEP values and for wave I latency of BAEP. Glycosylated hemoglobin values were correlated with BAEP and SEP abnormalities in many patients in both groups. Furthermore, in group 2, glycemic values correlated with SEP abnormalities. We therefore conclude that neurophysiological abnormalities are present at different levels in IDDM and NIDDM patients only a few years after clinical diagnosis and before the appearance of overt complications, and these abnormalities seem to be correlated with metabolic control status.

Adult↗
PubMed1987

Immunology in diabetic pregnancy: activated T cells in diabetic mothers and neonates.

Lymphocytes bearing surface antigens indicating early and full activation have been evaluated, in addition to T cell subsets, in blood samples from diabetic pregnant patients, neonates from diabetic mothers and control groups. The type of diabetes and the trimester of pregnancy were taken into account. Monoclonal antibodies were used to enumerate total T cells, helper/inducer, cytotoxic/suppressor Tlymphocytes and activated mononuclear cells using antibodies binding lymphocyte surface antigens as markers of early lymphocyte activation, and MHC Class II surface antigens as markers of late activation. A decrease in T-helper cells during the third trimester of pregnancy in Type 1 (insulin-dependent) and gestational diabetic patients (p less than 0.02) and a decrease in T-suppressor cells in Type 2 (non-insulin-dependent) diabetic pregnant patients during the third trimester (p less than 0.01) were observed in relation to normal values. As in normal pregnancy, 4F2-positive cells were increased in 48% of diabetic pregnant patients during the second and third trimesters of gestation. Class II-positive cells were increased in almost 60% of Type 1 and gestational diabetic patients during the last trimester of pregnancy in comparison with normal pregnant women and control subjects. A decrease in T-helper cells (p less than 0.02) and a clear increase in 4F2-positive cells (p less than 0.001) and Class II-positive lymphocytes (p less than 0.005) were observed in the infants of diabetic mothers in comparison with control subjects. The maternal cellular immune system, actively altered in pregnancy, is fully activated in a number of Type 1 and gestational diabetic pregnant patients. Activated lymphocytes are even found in the neonates of diabetic mothers, but these do not trigger the events leading to the onset of diabetes in the short term.

Adult↗
PubMed1987

Humoral and cellular immune abnormalities in neonates of diabetic mothers: any pathological role?

Insulin antibodies, insulin complexes, T-cell subsets and T-cells bearing surface antigens indicating early activation were studied in 35 and 24 infants of diabetic and of normal mothers respectively, which were compared with normal adult control subjects. Anti-insulin antibodies were evaluated using a modified version of Andersen's method, insulin complexes were assessed by a method developed by us; total T cells, helper/inducer and cytotoxic/suppressor T lymphocytes, and early activated T lymphocytes were determined using the monoclonal antibodies OKT3, OKT4, OKT8 and 4F2 respectively. The presence of insulin antibodies was correlated to macrosomia, hypoglycaemia and respiratory distress syndrome. Insulin-anti-insulin complexes were found in some of the neonates and were likely to have been formed by maternal antibodies and insulin from the neonate. Modifications of T-cell subsets were found in the neonates both of diabetic and of normal mothers. --Despite the presence of these immune abnormalities in some infants of diabetic mothers, the clinical onset of diabetes was not diagnosed in any of the cases studied. Nevertheless, the immunological abnormalities in neonates of diabetic mothers have short-term pathogenetic effects which raises the question of their possible long-term effect.

Adult↗
PubMed1987

Sensitive immunoenzymatic assay for urinary immunoglobulin subclasses of different pH: its significance in diabetic patients.

In search of a marker for monitoring the progression of diabetic nephropathy from the stage of charge- to that of size-selectivity loss, attention has been focused on the evaluation of immunoglobulin G (IgG) subclasses in the urine. We have developed a new sensitive enzyme immunoassay for the quantitation of urinary IgG1 and IgG4. Mouse monoclonal antibodies specific for each subclass were bound to microtitre wells precoated with rabbit anti-mouse immunoglobulin antibody. IgG1 and IgG4 of standard preparations (or of samples to be tested) were revealed using peroxidase-conjugated rabbit anti-human IgG. The procedure was carried out at 4 degrees C. This method can detect about 2 ng/ml of IgG4 and 20 ng/ml of IgG1. The monoclonal antibodies used were shown to be highly subclass-specific. IgG1 and IgG4 have a similar molecular weight but a different pH (about 9 and 4.6 respectively); a change in their ratio in the urine of diabetic patients may indicate a progressive deterioration of kidney function at the stage of incipient diabetic nephropathy.

Diabetic Neuropathies↗
PubMed1986

Activated T cells in normal pregnant women and neonates.

The phenotyping of T-cell subsets and T cells at different stages of activation was performed using a panel of monoclonal antibodies in samples from normal pregnant women at different stages of gestation and in the cord blood of neonates. The data obtained from pregnant women showed a slight decrease in the total number of T cells at the beginning of pregnancy, whereas there was a clear increase in 4F2-positive lymphocytes after a few months of gestation. No significant increase in Class II-positive lymphocytes was observed in normal pregnant women in comparison with adult healthy women. The data from neonates revealed a clear decrease of OKT3- and OKT4-positive cells and an increase of 4F2-positive cells in comparison with control subjects. These data indicate that alerted, but not fully activated, lymphocytes are present in the circulation of both the mother, after the first months of pregnancy, and the neonate. This finding reinforces the concept that during pregnancy there is an activation of certain immune components rather than a general depression of the immune system.

Adult↗
PubMed1986

A sensitive routine assay for urinary albumin based on the competitive binding to anti-albumin antibodies in solid phase.

The detection of microalbuminuria has a high prognostic value in diabetic patients with no symptoms of clinical nephropathy. Attention has been focused on the development of a simple, reproducible, specific, and, above all, sensitive method to detect albuminuria in the urine. The method is based on the competitive binding between albumin in the urine to be tested and a fixed amount of radiolabelled albumin to anti-albumin immunoglobulins in solid phase. The immunoglobulin C fraction of a rabbit anti-human albumin antiserum was left to coat highly adsorbent polystyrene microtitre tubes. While the aspecific tube binding was overcome by saturation with a solution of gelatine, increasing dilutions of standard albumin or the diluted urine samples to be tested were left to incubate with an equal volume of radiolabelled albumin at room temperature for 1 hour. The cold/hot albumin mixture was added to anti-albumin immunoglobulin-coated tubes, which had been repeatedly washed, and left to incubate. After washing, radioactivity was assessed. This assay has proved to be fast, simple and highly sensitive since it detects up to 25 ng of albumin per ml and is of value in large-scale screening for microalbuminuria in diabetic patients.

Albumins↗
PubMed1986

Treatment of diabetic pregnant women with monocomponent insulins.

Very little immunological research has been undertaken in pregnant diabetic women in relation to insulin therapy. We investigated the relations between treatment with insulins of varied immunogenic character and the presence of immune factors such as insulin antibodies, immune complexes and insulin antiinsulin complexes as well as some maternal and neonatal complications of diabetic pregnancy. 128 insulin treated diabetic pregnant women and 121 of their newborns were included in the study. The incidence of insulin antibodies, immune complexes and insulin antiinsulin complexes was lower in patients treated with highly purified insulins than in those treated with conventional insulins. The insulin antibody levels were significantly related to the occurrence of maternal and neonatal morbidity. The presence of insulin antiinsulin complexes in the cord blood of infants of diabetic mothers was related to the presence of these complexes in their mothers. Our results seem to indicate that the use of highly purified insulin could favour the outcome of diabetic pregnancy.

Antigen-Antibody Complex↗
PubMed1986

Immunity in Graves' disease at diagnosis: correlation between activated T cells and humoral immune factors.

Activated T cells, T-cell subsets, thyrotropin receptor antibodies and immune complexes were evaluated in 31 patients with newly diagnosed Graves' disease. Activated T cells were assayed by monoclonal antibodies against early (4F2) and late activation surface lymphocyte antigens (different epitopes of class II antigens). In comparison with the normal population, Graves' patients showed a significant decrease in the suppressor cytotoxic T-cell subset. Significant increases of 4F2-positive cells (70% of patients studied), class II antigen-positive cells (65%), thyrotropin receptor antibodies (93%), Clq-immune complexeses (44%) and conglutinin-immune complexes (37%) were observed. A significant inverse correlation between the increase in 4F2-positive cells and thyrotropin receptor antibody values was also observed. Lymphocytes from Graves' patients were cultured in the presence of thyrotropin receptor antibody-positive or -negative sera, with or without mitogen stimulation. Thyrotropin receptor antibodies were shown not to interfere with the expression of activation antigens in cultured cells. The different patterns of humoral and cellular immune phenomena may indicate the existence of either different stages of Graves' disease or a heterogeneity of the immunopathogenesis in different patients.

Adolescent↗