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Biomedical subjects

D Andreani

Publications and source records attributed to D Andreani.

At least 19 recordsLinked to original sources
PubMed1992

Ocular myopathy without ophthalmoplegia can be a form of mitochondrial myopathy.

To characterize muscle pathology in 3 cases affected by ocular myopathy with eyelid ptosis and upper facial weakness, but without ophthalmoplegia, light microscopy and ultrastructural study were performed on levator palpebrae, orbicularis oculi and deltoid muscle biopsies. While levator palpebrae proved uninformative because of the massive fibrous degeneration of muscle, orbicularis oculi biopsies showed histochemical and ultrastructural alterations indicating a mitochondrial involvement, resembling that reported in ocular mitochondrial myopathies (OMM). On the other hand very mild aspecific findings were observed in deltoid. We suggest that these cases with ocular myopathy and without ophthalmoplegia should be considered a partial or initial form of OMM.

Adult↗
PubMed1992

Selective decrement of anionic immunoglobulin clearance after induced renal hemodynamic changes in diabetic patients.

The charge permselectivity of proteins was evaluated in diabetic patients after systemic and renal hemodynamic changes induced by an intravenous injection of an angiotensin-converting enzyme inhibitor (captopril) or of clonidine. Anionic immunoglobulin clearance (IgG4) was compared with that of total immunoglobulins, which have the same size but are mostly cationic, and of albumin. Ten type I hypertensive diabetic patients (group 1), 10 type 2 hypertensive diabetic patients (group 2), 5 type 1 normotensive diabetic patients (group 3), 10 subjects with essential hypertension (group 4), and 7 normal volunteers (group 5) received an intravenous injection of captopril (25 mg/100 ml in 5 min). Twelve of the hypertensive diabetic patients underwent a second provocative test with clonidine (150 micrograms/100 ml) (group 6) or placebo (100 ml saline) (group 7) with the same procedure. None of the patients had clinical nephropathy or other disorders. Glomerular filtration rate (GFR) and renal plasma flow (RPF) were measured before and during the tests. A significant decrease in diastolic blood pressure was observed in groups 1, 2, 4, and 6, together with an increase in the GFR and RPF values in groups 1, 2, 3, and 4 only, as well as a decrease in renal vascular resistances in groups 1, 2, 3, 4, and 6. Both clearances and fractional clearances of IgG4 and IgG decreased after captopril in groups 1 and 2.2+ The decrease in IgG4 clearance was correlated to that of renal vascular resistances in group 1 patients. A significant decrease in the anionic-cationic immunoglobulin ratio (IgG4/IgG) was observed in groups 1, 2, and 3.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Viral infection induces cytokine release by beta islet cells.

Viral infection has been suggested to play a triggering role in the pancreatic beta cell destruction which occurs in insulin-dependent diabetes (IDDM). However, the underlying mechanism of this phenomenon is unknown. In this study a human insulinoma cell line has been infected with measles, mumps and rubella viruses since a temporal association is reported between the clinical onset of IDDM and diseases caused by these viruses. The infection with measles and mumps viruses induced the release of interleukin-1 (IL-1) and interleukin-6 (IL-6) by the cell line as assessed by a bioassay and up-regulated the expression of human leucocyte antigen (HLA) class I and class II antigens as evaluated by cytofluorimetric analysis. Stimulation with rubella virus induced the release of IL-6 only and had no effect on HLA antigen expression. These data show for the first time that IL-1 and IL-6 secretion by an insulinoma cell line may occur after viral infection and suggest that cytokine release and increased expression of HLA molecules by beta cells may act to induce the immune response towards beta cells in IDDM.

Cell Line↗
PubMed1991

Cytokines in sera from insulin-dependent diabetic patients at diagnosis.

Cytokines are known to play an important role in autoimmunity and have been suggested to be involved in the pathogenesis of insulin-dependent diabetes (IDDM). In the present study we have measured IL-1, IL-2, IL-4, IL-6, interferon-gamma (IFN-gamma) and tumour necrosis factor (TNF) (using both immunoassays and bioassays) in sera from 50 patients affected by IDDM at the time of clinical diagnosis and 51 age and sex matched controls. Detectable levels of IL-1, IL-2, IL-6 and IFN-gamma were found in the serum of a small percentage of subjects and were not significantly different between patients and controls. IL-4 was detectable in a higher number of both patients and controls and circulating TNF-alpha (greater than 1 U/ml) was found in a percentage of patients (24%) significantly higher than controls (P less than 0.01). Raised levels of TNF-alpha were detectable using an immunoenzymatic assay whereas TNF bioactivity in these samples was negligible. We conclude that the presence of immunoreactive TNF-alpha in the patient's sera may reflect an increased localized production of this cytokine at pancreatic level. However, the measurement in serum of other cytokines does not add information on the role that they may play in the pathogenesis of IDDM.

Cytokines↗
PubMed1991

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.

Adult↗
PubMed1991

Advanced nonenzymatic glycation endproducts (AGE): their relevance to aging and the pathogenesis of late diabetic complications.

Several studies in the last decade have highlighted the importance of the hexose sugars and especially glucose, as being responsible for alterations to living protein and other molecules. The phenomenon of nonenzymatic glycation--by which the carbonyl group of glucose can directly condense with a free amino group--may be relevant for the process of aging and for the pathogenesis of late diabetic complications. Thus life-long exposure to normoglycemia in non diabetic subjects or a shorter exposure but continued association with a hyperglycemic milieu, as in diabetes mellitus, have both been shown to lead to the formation and accumulation of irreversible and highly reactive advanced glycation endproducts (AGE) over long-lived, fundamental molecules such as the constituents of arterial wall collagen, basement membranes, nerve myelin, DNA and others. For example, the introduction of foreign AGE groups into proteins might alter their tertiary structure and therefore modify their function or activity. By increasing protein-to-protein cross-links AGE could reduce protein turnover, with consequential increases in levels of modified and thus less reactive molecules. Moreover, AGE could initiate an immune response with the production of specific antibodies. Reducing the extent of nonenzymatic glycation could effectively reduce the accumulation of AGE. Many authors are experimenting with methods to achieve this aim. Amongst the products tested are aspirin and aminoguanidine which compete with glucose for the same protein amino group. D-lysine is also being investigated on the principle that by reacting with glucose in circulation, it could effectively prevent it from reaching the amino group on the protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1989

The natural history of lymphocyte subsets infiltrating the pancreas of NOD mice.

A longitudinal study of lymphocytic infiltration in the endocrine pancreas of non-obese diabetic mice was performed to investigate the role of different lymphocyte subsets in the pathogenesis of diabetes. The incidence of insulitis and the percentage of mononuclear cell subsets in the pancreas were evaluated in non-obese diabetic mice of various ages (5, 9, 13, 17, 22, 29 and 36 weeks). Cryostat sections of pancreas were stained with heamatoxilin-eosin or with different monoclonal antibodies against total T lymphocytes, helper T lymphocytes, cytotoxic/suppressor T lymphocytes, activated interleukin 2 receptor positive lymphocytes and B lymphocytes. A monoclonal antibody against Class-II antigens was also used. Positive cells were revealed by the immunoperoxidase technique. Insulitis was found in 5 weeks old mice but to a lesser extent than in adult animals. No significant variation between infiltrating cell subsets was found in different age groups. T lymphocytes ranged between 20.4% and 28.1%, B lymphocytes between 28.8% and 30.8% and Class-II positive cells between 22.8% and 32.2%. Interleukin 2 receptor positive cells ranged between 5.5% and 8.5% as detected with AMT-13 monoclonal antibody which recognise the interleukin 2 binding site. A higher percentage of activated cells was observed using another monoclonal antibody (7D4) directed against a different epitope of the interleukin 2 receptor, suggesting the presence of activated lymphocytes with interleukin 2 receptors saturated by interleukin 2. No insulin-containing cells were found to express Class-II molecules as demonstrated by a double immunofluorescence technique. Most infiltrating mononuclear cells were found to be positive for Class-II and L3T4 antigens or to be Class-II positive and express surface immunoglobulins.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

New parameters to monitor the progression of diabetic nephropathy.

The possible differential elimination of the anionic IgG4 and of the other cationic IgG molecules whose pH differs but whose other characteristics are similar, has been hypothesized as a possibly useful parameter in monitoring preclinical diabetic nephropathy. An enzyme-linked immunosorbent assay method has been developed, based on a sandwich technique with subclass-specific antiimmunoglobulin monoclonal antibodies, which detects about 2 ng/mL IgG4. A sensitive radioimmunoassay method has been used to detect IgG. Normoalbuminuric, microalbuminuric, and macroalbuminuric patients, together with normal control subjects, were included in the cross-sectional study. Whereas IgG levels were elevated, as expected, in macroalbuminuric patients, it was interesting to note that IgG4, but not total IgG, levels were elevated in microalbuminuric patients. The IgG4/IgG ratio was increased almost to the same extent in microalbuminuric and macroalbuminuric patients. These findings are strongly in favor of the selective elimination of the acid medium-sized protein, IgG4, in incipient diabetic nephropathy. The measurement of immunoglobulin subclasses in the urine appears to be a promising parameter to characterize and subgroup diabetic patients with preclinical diabetic nephropathy.

Adolescent↗
PubMed1989

Humoral and cellular immunological factors as possible markers of clinical relapse in HLA-typed Graves' patients followed with time.

Humoral and cellular immune factors were studied in 33 newly diagnosed Graves' patients at diagnosis and in 12 of these patients at regular intervals thereafter. All the patients were treated with carbimazole for 15 months (initially 60 mg and then 20 mg supplemented with L-Thyroxine). The incidence of relapse after treatment was 42%. Thyrotropin receptor antibodies (TRAb), T-cell subsets, K and NK cells and mononuclear cells expressing surface antigen markers of different activation were evaluated respectively by the use of a radioimmunoassay and a panel of monoclonal antibodies. Patients in the follow-up study were HLA-A, B, C and D typed. TRAb levels (91%) and levels of 4F2-positive cells (73%) and class II-positive lymphocytes (69.6%) were significantly increased in newly diagnosed Graves' patients in comparison with normal controls, whereas CD8 cells were significantly decreased. There was a significant inverse correlation between the increase in 4F2-positive cells and TRAb values. In the follow-up study both humoral and cellular immunological parameters showed a wide variation in levels, but TRAb, 4F2 and L243 values declined on average with respect to diagnosis. After 15 months some patients still showed abnormal values of activated T cells and TRAb values. All patients who relapsed (42%) after medical treatment showed a significant increase of 4F2-positive cells, and some of TRAb, some time before the appearance of clinical symptoms. Finally, no correlation was found between HLA type and relapse of the disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
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↗