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Biomedical subjects

D De Mattia

Publications and source records attributed to D De Mattia.

At least 19 recordsLinked to original sources

HHT in childhood: screening for special patients.

Hereditary hemorrhagic telangiectasia (HHT) or the Rendu-Osler-Weber disease is a systemic fibrovascular autosomal dominant dysplasia, recognised when three of the following four clinical manifestations are present, according to the proposal of Shovlin.: recurrent nosebleeds, lelangiectasias of the skin, visceral lesions, and positive family history. HHT is often difficult to diagnose on the basis of history and physical examination alone, especially in infants and children. The signs and symptoms of HHT are nonspecific and are extremely variable within families. Given the frequent occurrence of clinically silent lesions in lung and brain arteriovenous malformations which can result in morbidity or death, much consideration should be given to screening patients with HHT for asymptomatic fistulae and to their treating once they are discovered. Presymptomatic interventions in such cases may substantially affect the outcome. It may be possible to state that lesions of HHT arise early in life, but do not reach sufficient size to cause symptoms until the second decade. Furthermore, as clinical manifestations often occur later in life, the development and the implementation of a molecular diagnosis will allow the identification of subjects with no evident signs of the disease but carrying the familial mutation. This is fundamental in order to establish reliable screening protocols for the prevention and cure of the disease and, to determine the presence of family members with no disease-associated mutation, who do not require further clinical screening.

Aging↗

Management of liver disease in thalassemia: main drug targets for a correct therapy.

Liver disease is the second cause of mortality in thalassemia major. We present a review on the hepatic damage in thalassemic patients aimed at a knowledge of current preventive, diagnostic and therapeutic approaches, useful to guide in clinical judgment and treatment decisions. Transfusion related iron overload and hepatitis are the causes of liver damage in thalassemic patients. We examined means of primary prevention, anti-hepatitis vaccinations, blood donors screening; diagnostic tests for secondary prevention (computed tomography, magnetic resonance imaging, super conducting quantum interference device and biopsy) were also discussed about. A survey of treatment methods and strategies ( chelation therapy, antiviral treatments and liver and bone marrow transplantation) follows.

Antiviral Agents↗

Streptococcus pneumoniae nasopharyngeal colonization in young healthy children: rate of carriage, serotype distribution, and antibiotic resistance.

The nasopharyngeal colonization rate of Streptococcus pneumoniae and its antibiotic susceptibility was determined in a given population of 317 young children (ages 1-7 years) in the area of Bari, Italy. 18.29% of the cultures were positive for S. pneumoniae. 8.62% of the strains were intermediately resistant to penicillin. Erythromycin-(65.51%) and cotrimoxazole-(17.24%) resistance was also observed whereas all the strains resulted uniformely susceptible to cefotaxime and ceftriaxone. The high rate of nasopharyngeal carriage of Streptococcus pneumoniae along with the resistance to antibiotics widely used in the community suggests the importance of epidemiological surveillance as well as the application of new vaccine strategies.

Carrier State↗

[Nasopharyngeal colonization of Streptococcus pneumoniae in healthy children: percentage of carriers, serotypes distribution and antibiotic resistance].

AIM: The nasopharyngeal carriage of Streptococcus pneumoniae is an important risk factor for pneumococcal diseases. Data regarding prevalence and serotype distribution of this pathogen are lacking in our population. METHODS EXPERIMENTAL DESIGN: longitudinal observational cohort study. SETTING: healthy children aged 1-7 years attending day-care centers and schools of a district of a Southern Italy city. MEASURES: the nasopharyngeal colonization rate of Streptococcus pneumoniae as well as its antibiotic susceptibility was determined. RESULTS: Of 317 nasopharyngeal cultures obtained, 18.29% of the cultures were positive for Streptococcus pneumoniae; 60.34% of the isolates were serotypes 19A, 19F, 14, 6B, or 23F; 8.62% of the strains were intermediately resistant to penicillin. Erythromycin-resistance was observed in 65.51% of the micro-organisms isolated and particularly serotypes 19, 14, and 6 were more erythromycin-resistant than organisms of other serotypes. Co-trimoxazole resistance was detected in 17.24% of the strains. All the strains resulted uniformly susceptible to cefotaxime and ceftriaxone. CONCLUSION: The high rate of nasopharyngeal carriage of Streptococcus pneumoniae, along with the resistance to antibiotics widely used in the community, suggests the importance of an epidemiological surveillance as well as the application of new vaccine strategies.

Anti-Bacterial Agents↗

Defective surface expression of attractin on T cells in patients with common variable immunodeficiency (CVID).

The proliferative responses of T lymphocytes of a subset of patients with CVID are abnormally low. This may be due to abnormalities in extracellular interactions or signalling defects downstream from membrane-associated receptors. Demonstrating that the T cell receptor signalling was normal, we observed no abnormal pattern of activation-induced tyrosine phosphorylation in cells from CVID patients. Moreover, the addition of exogenous IL-2 increased the low proliferation to mitogens, thus indicating the integrity of the IL-2R signalling apparatus. Attractin is a rapidly expressed T cell activation antigen involved in forming an association between T cells and monocytes. Twenty-four to 48 h after activation by CD3 cross-linking, attractin expression was not up-regulated on the cells of CVID patients despite normal up-regulation of CD25 and CD26. On control cells, however, attractin expression was up-regulated together with CD25 and CD26. The addition of the purified 175-kD attractin was capable of restoring the proliferative response of peripheral blood mononuclear cells following CD3 X-L in the presence of suboptimal concentrations of rIL-2 (10 and 20 U/ml). The effect was dose-dependent with the maximal effect at a concentration of 500 ng/ml, and present at a concentration as low as 50 ng/ml. Due to the likely role of attractin in cell guidance and amplification of the immune response, our results indicate that the lack of up-regulation of the molecule in patients with CVID may in turn affect any further step of productive immune response. Our finding may also imply a potential therapeutic role for this novel molecule.

Adolescent↗

Development of autologous T lymphocytes in two males with X-linked severe combined immune deficiency: molecular and cellular characterization.

We report on two patients affected with severe combined immune deficiency (SCID) with an unusual immunological phenotype and a substantial number of autologous, poorly functioning T cells. Distinct mutations identified at the IL2RG locus in the two patients impaired IL-2-mediated signaling but affected T-cell lymphopoiesis differently, resulting in generation of a polyclonal or oligoclonal T-cell repertoire. These observations add to the growing complexity of the immunological spectrum of SCID in humans and indicate the need for detailed immunological and molecular investigations in atypical cases.

Adolescent↗

Thrombin generation in children with acute lymphoblastic leukemia: effect of leukemia immunophenotypic subgroups.

Elevated plasma concentrations of endogenous thrombin generation markers and thrombotic events have been reported in children with leukemia. The aim of this study was to evaluate the effects of cancer and its treatment on thrombin generation (TAT levels) in children with acute lymphoblastic leukemia (ALL). The authors evaluated 32 children (23 M, 9 F) aged between 1 and 15 years (mean 6) affected by ALL (immunophenotypic subgroups: 16 common, 7 T, and 9 pre-B type). In all patients TAT levels at onset and after 5-6 doses of L-asparaginase were evaluated. TAT levels were higher in patients both at onset (13.04 +/- 10.90 ng/L) and after the 5-6 doses of L-asp (19.41 +/- 11.05 ng/L) with respect to controls (4 +/- 1 ng/L) (p < .001 and p < .001). TAT levels after 5-6 doses of L-asp were higher than those at onset (p < .001). Factorial ANOVA showed that at onset there was a significant effect of leukemia immunophenotypic subgroups upon TAT levels (p < .05) and no effect of inherited thrombotic risk factors. These results indicate that in children with ALL an important role is played by acquired thrombotic risk factors, among which the indirect cancer procoagulant activity has its importance.

Adolescent↗

Factors influencing effectiveness of deferiprone in a thalassaemia major clinical setting.

The effectiveness of deferiprone (L1) and the influence of other factors were determined in a clinical setting. Patients of Southern Italian origin, affected by beta-thalassaemia major (n = 13: 7 M, 6 F), aged 10-28 years (median 18 years), were treated with L1 within a 'Controlled Programme' of the Italian Ministry of Health. Desferrioxamine could not be administered in these patients because of anaphylactic reactions or other serious side effects. L1 was considered to be effective when the liver iron concentration was reduced or stable as measured by biomagnetic liver susceptometry. L1 proved to be effective in 3 out the 9 evaluable patients. A high pre-L1 iron overload was the main clinical factor influencing L1 effectiveness.

Adolescent↗

Acute childhood idiopathic thrombocytopenic purpura: AIEOP consensus guidelines for diagnosis and treatment. Associazione Italiana di Ematologia e Oncologia Pediatrica.

BACKGROUND AND OBJECTIVE: A recent evaluation carried out by the Associazione Italiana di Ematologia e Oncologia Pediatrica (AIEOP) about practice management of acute childhood idiopathic thrombocytopenic purpura (ITP) revealed a remarkable difference of behaviors among the different AIEOP centers. A need for common practice guidelines for this frequent illness arose from this observation. Our aim was to make the diagnosis and treatment of childhood ITP uniform. In the future we will evaluate the influence of these guidelines on practice behaviors. DATA SOURCES AND METHODS: Our main reference was the 1996 document produced by the American Society of Hematology (ASH). Their recommendations were updated with information from literature searched for in the MEDLINE database (June 1996-October 1998); search terms included: thrombocytopenia, ITP, diagnosis, therapy, children. The computerized search retrieved 83 articles. DATA EXTRACTION: the scientific validity of the literature was evaluated by a panel of members using published guidelines. The strength of the evidence was assessed using level of evidence criteria. Only data from level I and level II studies were taken in account. Only one study out of the 83 retrieved articles met these selection criteria and it was considered in addition to the 11 out of 581 articles selected in the ASH ITP guidelines. This preliminary work pointed out each issue about ITP not addressed by clinical studies and all participants in a Consensus Conference expressed their opinion about these issues. RESULTS: Diagnosis is essentially based on history, physical examination, a complete blood count and an examination of the peripheral blood smear. Treatment is recommended taking into account the clinical picture and number of platelets. The main difference between these guidelines and those from ASH are: AIEOP guidelines rely on the opinion of the members of the consensus conference, ASH ones on a panel of experts; therapeutic options include only products available in Italy; the indications to treatment rely more on clinical picture than on platelet number. INTERPRETATION AND CONCLUSIONS: These are explicitly developed, evidence-based practice guidelines to assist Italian pediatricians in making decisions about diagnosis and appropriate health care for patients with acute childhood ITP.

Acute Disease↗

Mutational screening of thrombopoietin receptor gene (c-mpl) in patients with congenital thrombocytopenia and absent radii (TAR).

Thrombocytopenia with absent radii (TAR) is a rare autosomal recessive disease characterized by hypomegakaryocytic thrombocytopenia and bilateral radial aplasia. We performed mutational screening of coding and promoter regions of the c-mpl gene, encoding thrombopoietin (TPO) receptor, by sequence analysis in four unrelated patients affected by TAR syndrome. Our results indicate that c-mpl gene mutations are not a common cause of thrombocytopenia in TAR syndrome.

Adolescent↗

Resistance to activated protein C in thalassaemic patients: an underlying cause of thrombosis.

We evaluated 81 thalassaemia major and 4 thalassaemia intermedia patients (48 M, 37 F), median age 17 years; 62/85 patients were HCV-positive, 3/85 HIV-positive, 19/85 were splenectomized. Forty normal healthy children were recruited as the control group. The number of thrombotic events was studied retrospectively. Platelet poor plasma was filtered and quick-frozen at -70 degrees C until time of assay. APC resistance was measured in an activated thromboplastin time and results were expressed as normalized ratio. All tests were done with diluted 1 in 5 (v/v) factor V deficient plasma and with undiluted plasma. Molecular genetic investigation of factor V gene was performed with polymerase chain reaction, followed by digestion of amplified products with restriction enzyme Mnl I. Data obtained with molecular investigation revealed the presence of 4 heterozygous subjects for factor V Leiden (4.7%). Functional tests were able to detect all heterozygotes for factor V Leiden both with undiluted and with diluted plasma, and there were no false negative subjects. However, undiluted plasma revealed a greater number of false positive subjects (n=15) than did diluted plasma. Therefore, tests done with undiluted and diluted plasma revealed a 100% sensitivity, while specificity was 81% for undiluted plasma and 97% for diluted plasma. Only one thrombotic event was observed in one of the 85 studied patients, as a case of stroke in a thalassaemia intermedia patient with APC resistance. In the same patient an additional thrombogenic risk factor was represented by a pronounced haematocrit increase at the beginning of her transfusion regimen.

Adolescent↗

Thromboembolic events in beta thalassemia major: an Italian multicenter study.

Thromboembolic (TE) events have been frequently reported in beta-thalassemic patients in association with known risk factors such as diabetes, complex cardiopulmonary abnormalities, hypothyroidism, liver function anomalies, and postsplenectomy thrombocytosis. In a recent survey involving 9 Italian thalassemic centers, we identified 32 patients with TE episodes in a total of 735 subjects, of whom 683 had thalassemia major and 52 thalassemia intermedia, corresponding to 3.95 and 9.61%, respectively. There was a great variation in localization: the main one (16/32) was CNS, with a clinical picture of headache, seizures and hemiparesis. Other localizations were the pulmonary (3 patients), mesenteric (1 patient) and portal (2 patients) sites. There were 6 cases of deep venous thrombosis (2 in the upper limbs, 4 in the lower ones). Intracardiac thrombosis was found in 2 subjects and clinical and laboratory signs of DIC were observed in 2 others during pregnancy. Since our patients with TE events present a statistically significantly higher incidence of associated dysfunction (cardiomyopathy, diabetes, liver function anomalies, hypothyroidism) than those without TE events (50 vs. 13.8%), we suggest close monitoring of those patients who are at higher risk of developing TE events because of the presence of one or more of these predisposing factors.

Adolescent↗

Immunity to tetanus in the 3-20 year age group in Italy.

In Italy, systematic mandatory tetanus immunization of children started in 1968. In 1989, immunity against tetanus was assessed in a random sample of 758 healthy subjects aged 3-20 y, from four Italian cities. There were 257 subjects 3-5 y old all residing in Southern Italy and 501 subjects 11-20 y old from both the South and North. The overall prevalence of non-immune subjects was 19.1%, without difference by sex. The rates of subjects lacking protective antibody titres was 25.3% in children 3-5 y old (all coming from South and the islands), 11.5% in those 11 y old, and 18.9% in the 18-20 y age-group, respectively. Subjects 11-20 y old residing in the South and the islands were more likely to be non-immune that those residing in the North (20.2% vs 6.0%; P < 0.01). Socio-demographic indicators such as lowest paternal education and largest family size were both unassociated with lack of protective antibodies. These findings indicate that an high rate of children in South of Italy do not have protective antibody levels, probably as consequence of lack of compliance with the vaccination programme. More efforts should be addressed to decrease geographical inequalities in the delivery of health care.

Adolescent↗

Growth deficiency in polytransfused beta-thalassaemia patients is not growth hormone dependent.

OBJECTIVE: Growth deficiency is commonly seen in polytransfused beta-thalassaemia patients, especially in adolescence. It is not completely dependent on the lack of their pubertal growth spurt. GH impairment at different levels (hypothalamic or pituitary) and/or a reduced IGF-1 synthesis have been suggested the main causes of stunted growth in these patients. We evaluated the relationship between GH reserve and growth in short beta-thalassaemia patients. PATIENTS: Twenty-nine short patients (height < -1.8 SDS for chronological age) were divided into two groups (low and normal responders) on the basis of their GH peak during insulin and clonidine tests (< or = and > 20 mU/l, respectively). All but one low responders underwent the GHRH test to exclude the impairment of somatotroph function and in eight of them an IGF-1 generation test was also performed. The two groups were compared with each other with respect to growth (height deficiency, height velocity, bone age and bone delay), haematological characteristics (serum ferritin levels, age at the start both of low (subcutaneous) s.c. infusion of desferrioxamine and of transfusional therapy) and serum IGF-1 and IGF-1 binding protein 3 levels. RESULTS: Thirteen patients (45%) (11 males, two females) were low responders, all but two having serum IGF-1 < 5th centile (< 0.1 centile in 42%); the GHRH test excluded the impairment of somatotroph function in 8/12. Height deficiency, serum ferritin levels, and age at the start of s.c. chelating therapy did not differ in low compared to normal responders. Height was negatively correlated both with the age at the start of s.c. chelating therapy and with serum ferritin levels. CONCLUSION: The reduction of GH reserve, more frequently due to a hypothalamic than to a pituitary dysfunction, is frequent in polytransfused beta-thalassaemia patients, especially in males. The height function is not related to the GH reserve, given the current methods for testing GH reserve. Late start of s.c. chelating therapy as well as haemosiderosis seem to play a role in the height deficiency, but not in GH reserve. Impairment of GH secretory reserve, therefore, cannot be considered the main cause of height deficiency in these patients.

Adolescent↗

Coagulation and fibrinolytic systems in the ill preterm newborn.

AIM: The activation pattern of the clotting and fibrinolytic systems in 63 preterm infants (GA 31, 6 +/- 2.3 weeks) was studied. METHODS: The infants were divided into four groups: (i) IRDS, (ii) asphyxia at birth, (iii) sepsis, and (iv) mild infection. A control group was composed of preterm infants without any apparent disease (GA 32 +/- 1.8 weeks). RESULTS: During IRDS we found a systemic activation of both coagulation and fibrinolysis at birth which was represented by lower levels of ATIII (27.7 +/- 8.8%) and significantly greater levels of TAT (37.9 +/- 31.9 ng/ml), D-dimers (1242.7 +/- 206.9 ng/ml), tPA Ag (10.9 +/- 5.3 ng/ml) and PAI Ag (59.9 +/- 16.7 ng/ml) than in the control group. In the asphyxiated newborns there were no significant differences from the controls. During their seventh day of life, a significant reduction of all the analysed parameters (TAT, D-dimers, tPA, PAI) and a significant increase in ATIII were seen in the newborns with IRDS, while no significant modification was observed in the newborns with asphyxia at birth. When the newborns with sepsis were compared with those with mild infection, their TAT and PAI values proved to be significantly higher for the first tests (21.7 +/- 18.8 vs 9.2 +/- 6.9 microg/l and 53.6 +/- 14.4 vs 37.7 +/- 10.2 ng/ml respectively). During the second tests, 7 days later, only TAT (16.7 +/- 14.7 vs 6.3 +/- 4 microg/l) levels remained high while D-dimers (1094.2 +/- 400.6 vs 646 +/- 200ng/ml) and tPA (11.3 +/- 8 vs 4.9 +/- 2 ng/ml) were significantly higher in the septic group of newborns than those with mild infection. CONCLUSIONS: These data indicate that there is an activation of the clotting and fibrinolytic systems both in the initial phase of IRDS as well as during sepsis.

Antithrombin III↗

Somatic-cell selection is a major determinant of the blood-cell phenotype in heterozygotes for glucose-6-phosphate dehydrogenase mutations causing severe enzyme deficiency.

X-chromosome inactivation in mammals is regarded as an essentially random process, but the resulting somatic-cell mosaicism creates the opportunity for cell selection. In most people with red-blood-cell glucose-6-phosphate dehydrogenase (G6PD) deficiency, the enzyme-deficient phenotype is only moderately expressed in nucleated cells. However, in a small subset of hemizygous males who suffer from chronic nonspherocytic hemolytic anemia, the underlying mutations (designated class I) cause more-severe G6PD deficiency, and this might provide an opportunity for selection in heterozygous females during development. In order to test this possibility we have analyzed four heterozygotes for class I G6PD mutations: two with G6PD Portici (1178G-->A) and two with G6PD Bari (1187C-->T). We found that in fractionated blood cell types (including erythroid, myeloid, and lymphoid cell lineages) there was a significant excess of G6PD-normal cells. The significant concordance that we have observed in the degree of imbalance in the different blood-cell lineages indicates that a selective mechanism is likely to operate at the level of pluripotent blood stem cells. Thus, it appears that severe G6PD deficiency affects adversely the proliferation or the survival of nucleated blood cells and that this phenotypic characteristic is critical during hematopoiesis.

Autoradiography↗