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M Viscardi

Publications and source records attributed to M Viscardi.

14 recordsLinked to original sources
PubMed2004

Identification of a novel polymorphism in the fibronectin type II domain of the SEL1L gene and possible relation to the persistent hyperinsulinemic hypoglycemia of infancy.

SEL1L, a human gene located on chromosome 14q24.3-q31, is highly expressed in adult pancreas. It is proximal to D14S67 (IDDM11) a proposed type I diabetes susceptibility locus. Considering the organ specific expression of SEL1L, a fundamental role of SEL1L in pancreatic growth can be hypothesized. While screening for mutations in young diabetic patients, in children affected by persistent hyperinsulinemic hypoglycemia of infancy (PHHI), in patients with non-functional endocrine tumours and in over 100 control subjects, we identified a novel polymorphism (D162G) residing on the fourth exon of the gene. This exon encodes for the fibronectin type II domain and the nucleotide change involves a highly conserved amino acid. The D162G polymorphism induces a major change in the amino acid composition producing a possible disruptive role in collagen binding.

Amino Acid Sequence↗
PubMed2003

Selection of bacteriophage-resistant mutants of Streptococcus thermophilus.

Phage-resistant mutants have been isolated from Streptococcus thermophilus. Selection was carried out using anti-phage antibodies or Hoechst 33258-labelled phages. Two mutants out of eight tested displayed reduced acidifying capacity. Selection of the bacteria that extruded more rapidly the fluorochrome 5-6-carboxyfluorescein diacetate (CFDA) restored the acidifying capacity of these two mutants to the level of the parental strains. Mutants displaying phage resistance and good acidifying capacity were obtained in 4-5 days. New phages that are able to overcome the protection mechanisms of the existing bacteria arise continually in the dairy environment. The procedures described here permit to replace promptly the starter culture susceptible to newly emerged phages with a resistant one.

Adsorption↗
PubMed2001

Macroamylasemia attributable to gluten-related amylase autoantibodies: a case report.

BACKGROUND: Macroamylasemia (MA) is a benign condition caused by circulating macroamylase complexes of pancreatic or salivary amylase bound to plasma proteins, which cannot be cleared by the renal glomeruli. In most cases, the macromolecular amylase represents a complex of normal amylase and either immunoglobulin A or G and may be a specific antigen-antibody complex. Celiac disease (CD) is a permanent intolerance to ingested gluten that results in immunologically mediated inflammatory damage of the small intestinal mucosa. Several recent population-based serologic surveys have shown CD to be a common disorder, possibly affecting 1 in 200 to 250 individuals in most countries studied, including the United States, where overt CD is rare, indicating a high proportion of subclinical disease. The diagnosis of CD currently rests on the histological demonstration of the characteristic lesion in the small intestine and the subsequent clinical response to the introduction of a gluten-free diet. MA associated with CD has been described in adult patients, and in a few cases, MA decreased or resolved after a strict gluten-free diet. A few single cases of MA have been described in childhood, but no association with CD has been reported so far. We report a girl with CD, autoimmune thyroiditis, and MA, in whom CD-related antibodies to amylase and to exocrine pancreas tissue resolved with a gluten-free diet. CASE REPORT: An 11-year-old girl was referred for chronic abdominal pain and growth retardation associated with persistent hyperamylasemia and suspected chronic pancreatitis. We confirmed elevated serum amylase, normal serum lipase, and very low 24-hour urine amylase and amylase clearance/creatinine clearance ratio, consistent with MA. Serologic tests for CD were positive, and the diagnosis was confirmed by small bowel biopsy showing subtotal villous atrophy. Thyroid function tests showed a pronounced hypothyroidism, associated with high titers of thyroid microsomal and thyroglobulin antibodies. Screening for other autoantibodies-including antinuclear, islet cell, glutamic acid decarboxylase, protein tyrosine phosphatase islet antigen 512, adrenal gland, and cytoplasmic neutrophil granulocyte antibodies-was negative. A diagnosis of CD, MA, and hypothyroidism attributable to autoimmune thyroiditis was made. A gluten-free diet and oral replacement with L-thyroxine was started with clinical improvement. Serum amylase and amylase clearance/creatinine clearance ratio normalized, consistent with resolution of MA. STUDY DESIGN AND METHODS: The patient's serum samples were obtained at the time of CD diagnosis and at 3 and 12 months after instituting a gluten-free diet. Serum samples from 10 consecutive untreated celiac children were disease controls, and 39 participants with no gastrointestinal symptoms and no family history of CD served as healthy controls. The origin of MA as determined by complexes of amylase with circulating immunoglobulins was tested by the measurement of amylase on supernatants after precipitation of immune complexes with either protein A Sepharose or polyethylene glycol. The precipitation of >60% of amylase activity was consistent with the presence of MA. Immunoglobulin G (IgG) and immunoglobulin A (IgA) circulating autoantibodies to amylase were measured using recently developed enzyme-linked immunosorbent assay (ELISA), using porcine amylase as antigen. Results were expressed as arbitrary units (AUs). Statistical analysis was performed by Student's t test for unpaired data. IgA and IgG antibodies to exocrine pancreas tissue were detected by indirect immunofluorescence on human pancreas cryosections. RESULTS: Serum immunoprecipitation with either protein A Sepharose or polyethylene glycol reduced amylase activity from 1698 to 89 U/L (94.8%) and to 75 U/L (95.6%), with only marginal reduction in control serum samples. The ELISA for autoantibodies to amylase detected high values, both IgA (3531 AU) and IgG (1855 AU), in the serum sample from the patient at CD diagnosis. IgA autoantibodies (mean +/- standard deviation) were 3.4 +/- 2.5 AU in healthy controls, and 2.1 +/- 1.2 AU in celiac controls; IgG autoantibodies were 10 +/- 4.8 AU in healthy controls and 8.5 +/- 3.2 AU, respectively. Autoantibodies to exocrine pancreas tissue were documented in patient sera at the time of CD diagnosis, both IgA and IgG, but not in control groups. Preincubation of patient's serum with excess of alpha-amylase specifically inhibited antibody binding to coated amylase in the ELISA, and partially inhibited immunoreactivity to exocrine pancreas. Autoantibodies to alpha-amylase and to exocrine pancreas declined in CD patients after institution of a gluten-free diet. CONCLUSIONS: Few cases of MA have been described in children, and in all amylase determination was part of the clinical investigation for abdominal pain or trauma. (ABSTRACT TRUNCATED)

Amylases↗
PubMed1998

Parameters associated with residual insulin secretion during the first year of disease in children and adolescents with Type 1 diabetes mellitus.

Factors associated with residual insulin secretion and spontaneous remission in Type 1 diabetic patients are important in the evaluation of treatment aimed at modifying the natural history of Type 1 DM. We investigated the effect of parameters at onset on residual beta cell function in 215 Type 1 DM children and adolescents. Blood gas analysis, HLA, GAD and IA-2 antibodies before the start of insulin treatment were recorded for each patient. Residual C-peptide secretion was assessed by the glucagon test, and parameters of metabolic control (HbA1c and insulin dose U kg(-1) day(-1)) were examined at disease onset and after 3, 6, and 12 months. Residual C-peptide secretion throughout the first year of disease was significantly reduced in patients with disease onset before age 5. Multiple regression analysis showed that low pH at onset showed a significant and independent association with reduced C-peptide at 3 months (p = 0.02) and that the detection of GAD antibodies had a significant independent association with decreased C-peptide secretion at 6 months of follow-up (p = 0.02). Insulin requirement was higher in the youngest patients group and in patients with GAD antibodies. Spontaneous insulin remission (HbA1c <6% and insulin <0.3 U kg(-1) day(-1)) occurred in 22/192 (11%) patients at 3 months of follow-up, in 15/190 (8%) patients at 6 months and in 8/169 (5%) patient at 12 months. Remission was more prevalent in older patients (p = 0.01) and in patients without detectable GAD antibodies: (14/64 vs 8/128, p = 0.001). Sex, IA-2 antibodies and HLA DR were not independently associated with C-peptide secretion, insulin requirement or remission in the first year of Type 1 DM. This study confirms the association of young age, severe acidosis at disease onset, and GAD antibodies with decreased residual beta-cell function and spontaneous remission during the first year of insulin treatment. These factors should be considered in trials evaluating therapies to retain beta-cell function and induce remission at and after disease onset.

Adolescent↗
PubMed1998

Simultaneous identification of antibodies to Brucella abortus and Staphylococcus aureus in milk samples by flow cytometry.

Two flow cytometric assays are described herein. The single cytometric test (SCT) detects antibodies to either Brucella abortus or Staphylococcus aureus in the serum or milk of a cow or water buffalo. The double cytometric test (DCT) detects both anti-B. abortus and anti-S. aureus antibodies concurrently. In the SCT, the sample to be tested is incubated in succession with the antigen (either B. abortus or S. aureus) and the proper secondary antiserum (fluorescein isothiocyanate-labelled rabbit anti-cow immunoglobulin antiserum or rabbit anti-water buffalo immunoglobulin antiserum). In the DCT, the sample to be tested is incubated first with B. abortus and S. aureus antigens and then with the secondary antiserum. The B. abortus antigen used in the DCT is covalently bound to 3-microm-diameter latex particles. The difference in size between B. abortus and S. aureus permits the establishment of whether the antibodies are directed against one, the other, or both antigens. When compared to the complement fixation test, the SCT and DCT each show a specificity and a sensitivity of 100%. The SCT has been used previously to detect anti-S. aureus antibodies. Here its use is extended to the detection of anti-B. abortus antibodies. The DCT is described here for the first time. The DCT appears to be useful for large-scale brucellosis eradication programs. It offers the possibility of using one test to identify animals that are serologically positive for both B. abortus and S. aureus.

Animals↗
PubMed1998

Growth changes in children and adolescents with short-term diabetes.

OBJECTIVE: Height and weight changes during the first 3 years of diabetes were prospectively followed in 152 diabetic children and adolescents. RESEARCH DESIGN AND METHODS: The study sample consisted of 152 Caucasian diabetic patients (84 boys; 68 girls) followed from diabetes onset in the Paediatric Diabetes Unit and 80 Caucasian normal subjects (49 boys; 31 girls) assessed in the Outpatient General Paediatric Clinic of the same hospital for routine examination and not affected by problems that might influence growth. Diabetic patients and control subjects were consecutively enrolled in the study between 1989 and 1992; diabetic patients with positive markers for celiac disease (positive antiendomysial antibodies) and thyroid disease (positive antimicrosomial antibodies) or any other chronic disease were not considered in the study. Mean age of diabetic patients (8.9 +/- 4.1 years) and control subjects (8.5 +/- 4.2 years) at recruitment in the study was similar. RESULTS: At onset of diabetes, the mean height expressed as the height standard deviation score (HSDS) was significantly greater than the expected values (P < 0.0001) and was independent of sex and pubertal stage. During the first 3 years of diabetes, HSDS decreased significantly (F = 6.9; P < 0.001). Meanwhile, growth velocity as standard deviation score (SDS) decreased significantly between the 1st and 2nd year (-0.12 +/- 2.1; -0.76 +/- 2.6, respectively; P < 0.05), but it was similar between the 2nd and 3rd year of diabetes. Weight expressed as SDS increased significantly during the first 2 years of diabetes but not thereafter. Height changes during the study period were independent from pubertal stage and sex. Metabolic control and insulin requirement, in our series, were not clearly related to height and weight changes. CONCLUSIONS: Diabetic patients at onset of diabetes are taller than age- and sex-matched nondiabetic subjects. During the first years of the disease, linear growth decreases independently of metabolic control and weight changes.

Adolescent↗
PubMed1997

DNA content differences in laboratory mouse strains determined by flow cytometry.

The nuclear DNA content of seven mouse laboratory strains has been measured by flow cytometry. The differences observed between strains as well as those between sexes within the strain were all statistically significant. The highest DNA content (approximately 6.4 pg/female nucleus) was found in the Balb/c strain; the lowest (approximately 5.7 pg/male nucleus) in the C3H/he strain. The difference between sexes varied from 1.6% (in CD-1 mice) to 6.3% (in nude mice). The interest of these results is twofold. First, the mouse can now be used to study the adaptive significance of genome size variation, so far studied only in plants. Second, DNA content analysis can become a quick method for mouse strain identification.

Animals↗
PubMed1997

Frequency and correlates of severe hypoglycaemia in children and adolescents with diabetes mellitus.

UNLABELLED: Frequency and correlates of severe hypoglycaemia have been retrospectively analysed in a cohort of diabetic children and adolescents with median (range) age 14.5 (3.2-25.5) years followed from the onset of the disease by the same diabetic clinic. During the years 1992-1994, 53 of the 187 patients reported 74 hypoglycaemic episodes: the average frequency of hypoglycaemia during the 3 years surveyed was 14.9 episodes/ 100 patients per year. Frequency of hypoglycaemia decreased significantly with age (chi 2 = 24.1; P < 0.0001) and was independent of duration of diabetes. Glycosylated haemoglobin and insulin dose were similar in patients with and without hypoglycaemia, matched for age and duration of diabetes. One out of two hypoglycaemic episodes occurred during sleep and no explanation was available for 50% of episodes. CONCLUSION: In this study severe hypoglycaemia was more frequent in young children than in adolescents and was independent of metabolic control and insulin dose.

Adolescent↗
PubMed1997

Simultaneous detection of cucumber mosaic virus, tomato mosaic virus and potato virus Y by flow cytometry.

The simultaneous detection is described of cucumber mosaic virus (CMV), potato virus Y (PVY) and tomato mosaic virus (ToMV) by flow cytometry. Extracts from leaves of healthy and CMV or PVY infected plants were incubated with latex particles, each with a diameter of 3 microm. Extracts from ToMV infected or uninfected plants, however, were incubated with particles, each with a diameter of 6 microm. Beads were washed and incubated in succession with primary and secondary antibodies, the latter labeled with phycoerythrin (PE) or fluorescein (FITC). CMV and PVY were distinguished on the basis of the fluorescence emitted by FITC and PE; ToMV was distinguished from CMV and PVY on the basis of the different diameter (6 microm) of the particles on which it was adsorbed. The three viruses were detected also by another approach. Latex particles with a diameter of 3, 6 and 10 microm were separately sensitized with antibodies specific for CMV, PVY and ToMV. An equal number of sensitized particles was mixed and incubated with the plant extracts containing the three viruses and then with anti-CMV, anti-PVY and anti-ToMV antibodies labeled with FITC. The study describes also a virus purification method based on the use of antibody coated latex particles. The method is simple technically and applicable to the purification of large as well as minute amounts of different viruses (CMV, PVY and ToMV).

Antibodies, Viral↗
PubMed1996

Carpal tunnel syndrome: which electrodiagnostic path should we follow? A prospective study of 100 consecutive patients.

We prospectively studied 100 consecutive patients (200 hands) sent to our Neurophysiopathology Service for a suspected Carpal Tunnel Syndrome (C.T.S.). We performed 6 different motor and sensitive electrodiagnostic tests on both hands of each patients and on 25 healthy subjects. We calculated the sensibility and the specificity of each test by comparing each parameter with all the other ones, and then, again, using the clinical evaluation as a "gold standard". The routinely performed tests proved to have a high sensibility in detecting C.T.S., nevertheless, sometimes they do not give a definite response. In these cases we suggest to carry out the neurophysiological examination by performing some of the newly proposed tests. We end our study by drawing a "flow-chart", which considers reliability, sensibility, difficulty in performing and/or evaluating, and discomfort for patients, of each test; by this we would give a guide and a practical aid in determining the electrophysiological path for C.T.S. diagnosis.

Action Potentials↗
PubMed1992

A case control study of CSF copper, iron and manganese in Parkinson disease.

To elicit possible variations in the CSF concentrations of copper, iron and manganese due to Parkinson disease (PD) or to the stage reached, we tested 11 patients with idiopathic PD, 6 untreated and 5 on long term L-dopa, versus 22 age and sex matched patients with other neurological disorders (control group-CG). The CSF levels of the three metals, measured by electrothermal atomization, did not differ significantly between the PD group and CG or between either of the PD subgroups and CG. Our findings therefore do not support the hypothesis that CSF Cu is a marker of PD.

Aged↗