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Biomedical subjects

V Conti

Publications and source records attributed to V Conti.

At least 19 recordsLinked to original sources
PubMed2006

A novel Leu153Ser mutation of the Fanconi anemia FANCD2 gene is associated with severe chemotherapy toxicity in a pediatric T-cell acute lymphoblastic leukemia.

Fanconi anemia (FA) is an autosomal recessive disease characterized by pancitopenia, congenital malformations, predisposition to cancers and chromosomal instability. We report the clinical and molecular features of a patient initially identified as a potential FA case only because of chemotherapy toxicity during the treatment of a T-lineage acute lymphoblastic leukemia (ALL). Cells from this patient showed a moderate chromosomal instability, increasing sensitivity to DNA crosslinking agents but normal response to ionizing radiation. The analysis of FA proteins demonstrated a marked reduction of FANCD2 (>95%), but normal levels of FANCA or FANCG. Interestingly, this defect was associated with a homozygous missense mutation of FANCD2, resulting in a novel amino-acid substitution (Leu153Ser) at residue Leu153, which is highly conserved through evolution. The FANCD2(L153S) protein, whose reduced expression was not due to impaired transcription, was detected also in its monoubiquitinated form in the nucleus, suggesting that the mutation does not affect post-translation modifications or subcellular localization but rather the stability of FANCD2. Therefore, the hypomorphic Leu153Ser mutation represents the first example of a FANCD2 defect that might promote clonal progression of tumors, such as T-ALL, and severe chemotherapy toxicity in patients without any clinical manifestations typical of FA.

Amino Acid Substitution↗
PubMed2006

Cord blood in vitro expanded CD41 cells: identification of novel components of megakaryocytopoiesis.

BACKGROUND: Megakaryopoiesis represents a multi-step, often unclear, process leading to commitment, differentiation, and maturation of megakaryocytes (MKs) that release platelets. AIM: To identify the novel genes that might help to clarify the molecular mechanisms of megakaryocytopoiesis and be regarded as potential candidates of inherited platelet defects, global gene expression of hematopoietic lineages was carried out. METHODS: Human cord blood was used to purify CD34+ stem cells and in vitro expand CD41+ cells and burst-forming unit-erythroid (BFU-E). We investigated the expression profiles of these three hematopoietic lineages in the Affymetrix system and selected genes specifically expressed in MKs by comparing transcripts of the different lineages using the dchip and pam algorithms. RESULTS: A detailed characterization of MK population showed that 99% of cells expressed the CD41 antigen whereas 73% were recognizable as terminally differentiated fetal MKs. The profile of these cells was compared with that of CD34+ cells and BFU-E allowing us to select 70 transcripts (MK-core), which represent not only the genes with a well-known function in MKs, but also novel genes never detected or characterized in these cells. Moreover, the specific expression was confirmed at both RNA and protein levels, thus validating the 'MK-core' isolated by informatics tools. CONCLUSIONS: This is a global gene expression that for the first time depicts a well-characterized population of cord blood-derived fetal MKs. Novel genes have been detected, such as those encoding components of the extracellular matrix and basal membrane, which have been found in the cytoplasm of Mks, suggesting that new physiological aspects of MKs should be studied.

Antibodies, Monoclonal↗
PubMed2006

[Health care and infective aspects in patients affected by common variable immunodeficiency assisted in the Lazio Regional Authority Reference Centre for Primary Immunodeficiencies].

Common variable immunodeficiency (CVID) is a chronic condition characterised by a predominant defect of humoral immunity. In most cases the diagnosis of CVID is made during adulthood; the main clinical features of CVID are chronic and relapsing infections (mainly of respiratory and gastroenteric tracts). CVID patients may also develop neoplastic and autoimmune diseases. In our centre (the Regional Centre for Primary Immunodeficiencies of the Lazio Regional Authority) we administered a 23-item questionnaire to 60 patients with CVID undergoing substitutive therapy with intravenous immunoglobulins (IVIG) about their demographic characteristics, time of clinical onset, time of diagnosis of CVID, clinical features, IVIG doses and administration intervals, and self-assessment of health status. In addition, the clinical history of all patients was reviewed, and the levels of serum IgG, IgA and IgM were evaluated and compared with the pre-therapy serum concentration. Moreover, an analysis of the treatment costs was performed. At onset, 67.2% of patients presented recurrent respiratory infections, and 50% had infections of the lower respiratory tract; 39.6% of the patients had gastroenteric infections. Most patients (57%) had recurrent infections of at least 2 of the respiratory, gastroenteric and/or urogenital tracts. In 37.9% of the group the diagnosis of CVID was made in less than 2 years after the beginning of symptoms, but in many cases (22.4%) the diagnosis took more than 10 years. 93% of patients are treated with a dose of IVIG between 6 and 15 g per administration, with intervals between 2 and 3 weeks. The review of patients'clinical history showed that 43% of patients have had respiratory infections during the follow-up in our Centre, 43% have splenomegaly (3% were also subjected to splenectomy) and 18.3% have autoimmune diseases. The mean concentration of IgG before the beginning of IVIG therapy was 235 mg/dl, while during the follow-up it was 664 mg/dl. Given the long time often required for diagnosis, general physicians and specialists should be better informed in order to make diagnosis swifter. The substitutive therapy with IVIG is effective in preventing recurrent infections and complications. A thorough follow-up is important for diagnosing neoplastic and autoimmune complications; in addition, immunologic analysis of peripheral blood and bone marrow are useful in identifying subgroups of patients with more severe clinical features. Finally, in selected patients, treatment costs may be controlled by modifying the dosage of IVIG or the intervals between administrations.

Adolescent↗
PubMed2006

Aspiration pneumonia. Pathophysiological aspects, prevention and management. A review.

Aspiration pneumonias occur more frequently than reported and, in many cases, the disease is not recognised. In hospitalised and institutionalised patients with predisposing diseases prompt diagnosis of this complication and correct preventive measures can drastically reduce the worsening of clinical conditions and the deaths due to aspiration pneumonia. Normal airway structure, effective defence mechanisms, and preventive measures are decisive in reducing aspiration episodes. An increased aspiration risk for food, fluids, medications, or secretions may lead to the development of pneumonia. Pneumonia is the most common respiratory complication in all stroke deaths and in mechanical ventilation patients. In addition, the increased incidence of aspiration pneumonia with aging may be a consequence of impairment of swallowing and the cough reflex. Dysphagia, compromised consciousness, invasive procedures, anaesthesia, insufficient oral care, sleep disorders, and vomiting are all risk factors. Aspiration pneumonia includes different characteristic syndromes based on the amount (massive, acute, chronic) and physical character of the aspirated material (acid, infected, lipoid), needing a different therapeutic approach. Chronic patients education and correct health care practices are the keys for preventing the events of aspiration. In patients at risk a clinical and instrumental assessment of dysphagia should be evaluated. Management includes the removal of etiologic factors (drugs, tubes, mobilisation, oral hygiene), supportive care, and in bacterial pneumonias a specific antibiotic therapy for community-acquired or nosocomial events.

Humans↗
PubMed2005

Brachial plexus injuries: regeneration timing and prognosis in patients without need for urgent operation. Preliminary results on truncus primarius superior.

BACKGROUND: In Italy, and more generally in the industrialised countries, traumatic nerve lesions have become more frequent. It is commonly accepted that it is necessary to wait 6 months after injury to suggest surgery if movement does not appear. In the scientific literature, there is no systematic clinical evidence of nerve regeneration timing after trauma., especially regarding brachial plexus. METHOD: We have performed a follow-up study of 15 consecutive patients with traumatic brachial plexus injuries involving truncus primaries superior without need for urgent surgery. In each patient an extensive clinical and neurophysiological evaluation was performed to detect the kind of lesion, level of lesion, severity of lesion and the outcome. FINDINGS: In our sample, some cases improved within a few weeks. This rapid improvement may be attributed to resolution of neuroapraxic block, in other cases slower improvement occurred due to rearrangement of motor units and axonal regeneration. In some cases voluntary activity clinically appeared after more than 6 months following injury. CONCLUSIONS: The current study is preliminary, but it provides evidence that a period of 6 months may not be sufficient for the reappearance of clinical movement. Moreover, current results confirm that neurophysiological evaluation may be a highly prognostic tool in traumatic nerve lesions. We hope that our study together with other data may provide us a timetable for expected nerve regeneration.

Brachial Plexus↗
PubMed2004

Adverse effects of GH self administration on peripheral nerve. A case report.

To our knowledge there is no evidence of multientrapment neuropathy related to growth hormone (GH) administration. We observed the case of a 45-year-old bodybuilder complaining of paresthesias and dysesthesias of the hands and feet after self-administration of high-dose of recombinant GH therapy. The patient complained of transitory symptoms after each cycle of GH therapy. The electrodiagnosis showed: 1) moderate right carpal tunnel syndrome (CTS) and minimal left CTS; 2) mild right ulnar entrapment at elbow; 3) a reduction of motor nerve conduction velocity of the left ulnar nerve across elbow; 4) a reduction of the amplitude of the sensory nerve action potential of the left ulnar nerve in digit-wrist segment; 5) the absence of the ulnar F wave bilaterally registering from abductor digiti minimus. Our data suggest a multiple entrapment condition of the upper limbs; furthermore, based on the history (paresthesia at feet), we can hypothesize a mild involvement of distal sensory fibres in the legs (neurophysiologically negative). The anecdotal history and neurophysiological findings of this case suggest an increased awareness to the adverse effects of GH on peripheral nerve.

Carpal Tunnel Syndrome↗
PubMed2003

Occult hepatitis C virus infection in type II mixed cryoglobulinaemia.

Mixed cryoglobulinaemia, when not secondary to other well-defined immunological disorders, is commonly associated with hepatitis C virus (HCV) infection. However, a minority of cases lack evidence of HCV infection and are, therefore, defined as 'true essential' mixed cryoglobulinaemias. We thoroughly investigated three such patients to determine the aetiology of this disorder. Antibodies to HCV (anti-HCV) and HCV RNA, detected by sensitive enzyme-linked immunosorbent and polymerase chain reaction assays in serum and in concentrated cryoglobulins, were repeatedly negative in the three patients. Despite the lack of evidence for HCV infection, two of them were still treated with interferon alpha-2a assuming unrecognized viral infection. Both patients demonstrated excellent clinical and laboratory responses, but cryoglobulinaemia relapsed after the withdrawal of therapy. At the time of relapse, HCV RNA genomic sequences were detected for the first time in the cryoprecipitates of both patients. In the third case, HCV RNA was demonstrated for the first time during a flare of cryoglobulinaemia coincident with varicella infection. In all three patients anti-HCV antibodies remained negative throughout follow-up. We conclude that some apparently 'essential' forms of mixed cryoglobulinaemia can be caused by occult HCV infection. Interferon therapy can be taken into consideration in such HCV-negative cases.

Adult↗
PubMed2001

Impairment of nasal mucociliary clearance after radiotherapy for childhood head cancer.

BACKGROUND: Radiotherapy of the head region in children is known to cause long-term sequelae, such as facial, dental, and ocular abnormalities. We investigated whether a decreased nasal mucociliary function occurs after radiotherapy of the head in children. METHODS: A saccharin/charcoal test was performed in 20 children treated with radiotherapy of the head and in 20 controls, age-matched and gender-matched. RESULTS: We found a decreased nasal mucociliary clearance (lower percentage of responses (p = 0083) and longer mucociliary transport times (p =.0001) in the patients compared with the controls. The radiotherapy dosage influenced the response to the test (p =.0046). CONCLUSIONS: Irradiation of the head in children may cause impairment of mucociliary function, even permanently, which may predispose children to upper respiratory infections. We would suggest careful monitoring of such patients to detect as early as possible the clinical effects of the functional changes and to prevent the evolution to chronic diseases.

Administration, Intranasal↗
PubMed2000

The insect attractant 1-octen-3-ol is the natural ligand of bovine odorant-binding protein.

Bovine odorant-binding protein (bOBP) is a dimeric lipocalin present in large amounts in the respiratory and olfactory nasal mucosa. The structure of bOBP refined at 2.0-A resolution revealed an elongated volume of electron density inside each buried cavity, indicating the presence of one (or several) naturally occurring copurified ligand(s) (Tegoni et al. (1996) Nat. Struct. Biol. 3, 863-867; Bianchet et al. (1996) Nat. Struct. Biol. 3, 934-939). In the present work, by combining mass spectrometry, x-ray crystallography (1.8-A resolution), and fluorescence, it has been unambiguously established that natural bOBP contains the racemic form of 1-octen-3-ol. This volatile substance is a typical component of bovine breath and in general of odorous body emanations of humans and animals. The compound 1-octen-3-ol is also an extremely potent olfactory attractant for many insect species, including some parasite vectors like Anopheles (Plasmodium) or Glossina (Trypanosoma). For the first time, a function can be assigned to an OBP, with a possible role of bOBP in the ecological relationships between bovine and insect species.

Animals↗
PubMed2000

Ear involvement in childhood Langerhans' cell histiocytosis.

BACKGROUND: Ear involvement (EI) in Langerhans' cell histiocytosis (LCH) occurs quite often. We reviewed the Italian pediatric population of 251 children with LCH diagnosed between 1982 and 1995, focusing on EI, to highlight the prevalence, the clinical presentation, the outcome during follow-up, and the prognostic impact of otologic LCH. METHODS: EI was defined by chronic otorrhea and/or mastoid infiltration, external auditory meatus lesions, and middle/internal EI. The age at diagnosis, sex, system involved, organ dysfunction, treatment, disease control, and outcome were recorded. RESULTS: EI was noted at presentation in 34 children (13. 5%). They had a younger age at diagnosis (p=.0013) and near totality of multisystem disease (93.8% of patients with EI). Among patients with multisystem disease, children with EI seemed to have a higher risk of poor response and a higher percentage of second line treatment (p=.003). CONCLUSIONS: EI seems to identify patients with a particular disease behavior, which requires a more accurate evaluation at diagnosis, staging and treatment, and a strict follow-up, considering the possibility of an unfavorable outcome.

Adolescent↗
PubMed2000

Native valve infective endocarditis: what is the optimal timing for surgery?

IE remains a dreaded disease masquerading under a myriad of presentations in an evolving epidemiological environment. In our continuing endeavor against this deadly disease, echocardiography has evolved into an indispensable diagnostic tool to define structural complications and guide therapy. Timing of surgical intervention for IE remains a subject of intense debate and depends on the cardiac and systemic complications of the infection, the virulence of the organism, and the responsiveness to medical therapy. A judicious agreement among cardiologist, cardiovascular surgeon, and infectious disease specialist should define whether surgical intervention is warranted and, if so, the optimal timing. Further optimization of guidelines will help in the diagnosis and treatment of endocarditis but will never be a substitute for sound judgment and experience.

Acute Disease↗
PubMed1999

cAMP-dependent protein kinase type RI is found in clusters in the rat detergent-insoluble neuronal fraction.

Different types of cAMP dependent regulatory subunits have been characterized in the mammalian brain: RI alpha and beta, RII alpha and beta. The subcellular distribution of RI subunits has been examined in the rat brain. Partial amino acid sequencing of tryptic fragments from the Triton insoluble pellet of the rat brain shows that cAMP dependent regulatory subunits type RI alpha are found in this fraction. Immunohistochemistry shows that Triton-insoluble RI subunits are concentrated to form clusters and this distribution is distinct from RII subunits. Immunohistochemistry and fluorescent cAMP labeling show that the clusters bind fluorescent cAMP analogues. These results suggest that the high local concentration of RI subunits can modulate cAMP distribution among different cellular compartments.

Amino Acid Sequence↗
PubMed1999

Polyclonal hypergammaglobulinemia at the onset of acute myeloid leukemia in children.

Polyclonal hypergammaglobulinemia (PHG) associated with hematological malignancies is a rare occurrence. We reviewed our series of 47 children with AML in order to define the prevalence of PHG and its prognostic value in achieving complete remission (CR) after induction treatment. Patients were stratified by immunoglobulin levels into two groups: with PHG and without PHG. CR reached after induction chemotherapy was considered a positive response. Conditional exact tests were used for the statistical analysis; conditional maximum likelihood estimates of the odds ratio (OR) were obtained. Significance levels (p) were determined from two-tailed tests. Twenty-two of 38 (57.9%) evaluable children showed PHG. Children with PHG and AML were more likely to be in CR after first induction treatment (OR=6.25, p=0.021), independent of sex, age at diagnosis, white blood cell count, percentage of blasts in the bone marrow, FAB phenotype, and treatment protocol. Infections seemed to positively influence early treatment response (p=0.038). PHG and infections were not statistically associated (p=0.16). PHG may result from the uncontrolled stimulation of B lymphocytes by cytokines. Infections or transfusions may act as triggers for the immune system, leading to the antileukemic effect seen in patients with AML and PHG going into spontaneous remission. It could be that this activation caused the larger number of CRs observed in our series. Clarification of why PHG exerts a positive influence on children with AML could help us to understand the ways by which the organism is able to control a malignant disease.

Acute Disease↗
PubMed1999

Thrombolysis with resolution of pulmonary hypertension in a heart transplant candidate.

We report a patient with idiopathic cardiomyopathy and high pulmonary resistance due to pulmonary emboli of unknown age. Successful thrombolytic therapy returned his pulmonary resistance to normal, allowing orthotopic cardiac transplantation. This case underscores the need to aggressively diagnose and treat pulmonary emboli in potential transplant candidates.

Adult↗
PubMed1998

Single turnover mechanism of a trypsin-reactor with high enzyme concentration.

A small column containing 2 mM CH-Sepharose 4B-immobilized trypsin was connected to a flow injection device equipped for potentiometric measurements (0.01-2 mM protons) and for post-column analysis by spectrophotometry and capillary electrophoresis (CE). The device was engaged with N alpha-benzoyl-L-arginine pNO2-anilide (BAPNA), beta-lactoglobulin (beta-Lac) and peptides of V8-protease predigested beta-Lac. At a given flow rate, the reaction with BAPNA or beta-Lac (below 2 mM) produced about 1 proton per substrate molecule in each sample (linear relation to substrate amount); with peptides (below 22 mM), the reaction did not exceed 0.17 acid equivalents per substrate molecule (hyperbolic dependence). Final experiments demonstrated that the reactor gave a correct estimate of available lysine in peptides of beta-Lac modified with 5-nitrosalicylaldehyde. The data could be predicted by a kinetic model describing the reactor performance in 'single turnover' conditions. The interplay between resident time and the non-catalytic amount of trypsin prevented each enzyme molecule from recycling as well as each substrate molecule (containing one or more cleavage sites) from encountering the enzyme more than once. In conclusion, both from the experimental and the theoretical point of view, this work permitted the analysis of trypsin behaviour in some extreme working conditions and indicates how to modulate the performance of an endoprotease-based reactor. A brief discussion on potential applications in protein mapping and tagging and in the quantitative analysis of protein bioavailability by means of a biosensorial strategy is also described.

Amino Acid Sequence↗
PubMed1995

Systemic gaseous microemboli during left atrial catheterization: a common occurrence?

OBJECTIVE: Gaseous microemboli during cardiac surgery have been implicated as a potential cause of postoperative neurologic injury. Any monitoring technique that exposes the systemic circulation to atmospheric pressure could introduce gaseous microemboli, causing cerebral microembolization. The incidence of carotid artery gaseous microemboli was studied during left atrial catheter insertion. DESIGN: Prospective clinical study. SETTING: Tertiary care university hospital. PARTICIPANTS: Twelve patients undergoing elective cardiac surgery. INTERVENTIONS: Perioperatively, a 5-MHz continuous wave Doppler probe was positioned over the left carotid artery to maximally record blood flow signals. The criteria used for detecting a gaseous microembolus were a sudden increase in the amplitude of the visual signal by 30% and a characteristic audible sound. MEASUREMENTS AND MAIN RESULTS: Numbers of microemboli at three timepoints (before and during left atrial catheter insertion and during catheter flushing) were assessed using the Friedman test. No emboli were detected before left atrial catheter insertion. When compared with the preinsertion time period, statistically (p < 0.05) significant numbers of gaseous microemboli were found in six patients during catheter insertion (3 +/- 1 microemboli; range 1 to 7 microemboli) and in five patients during catheter flushing (5 +/- 2 microemboli; range 1 to 12 microemboli). There was a tendency for patients with lower filling pressures to entrain more microemboli during insertion (r = 0.44; p = 0.149). No patient showed evidence of gross neurologic dysfunction postoperatively, although sensitive neurologic testing was not performed. CONCLUSIONS: Left atrial catheter insertion and flushing can cause systemic gaseous microemboli in more than 50% of patients. Although the number of microemboli introduced is relatively small, extreme care should be used during left atrial catheter insertion.

Adult↗