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Biomedical subjects

C Mazza

Publications and source records attributed to C Mazza.

At least 37 records · Page 2Linked to original sources
PubMed1997

Analyses of prognostic factors in a retrospective review of 92 children with ependymoma: Italian Pediatric Neuro-oncology Group.

The principal aim of this report is to present the results of multivariate analyses conducted to identify clinical prognostic factors in 92 children aged < 16 years with ependymoma (EPD) retrospectively collected in seven Italian centres. They were treated over a 16-year period (1977-1993). Treatment modalities varied. Surgery and radiotherapy (RT) was the "gold standard" management method for the majority of these children. Only in the late 1980s did some of them receive chemotherapy (CT), mainly with vincristine, lomustine (CCNU) and prednisone. The median follow-up of the entire study population is 36 months (average 43 months; range 12 to 214 months). The 10-year overall (OS) and the progression-free survival (PFS) of the study population were 55.5% (CI 41.4-69.4%) and 34.7% (CI 21.4-47.8%), respectively. Age (< 5 years; > 5 years), sex, site (infratentorial vs. supratentorial), histology (anaplastic/malignant vs. non-anaplastic/non-malignant), type of resection (complete vs. incomplete); use and fields of RT, and of CT employed were entered in a multivariate regression model to test their impact on OS and PFS. On univariate analysis, radical surgery, the use of RT and age more than 5 years at the time of diagnosis achieved statistically significant values for predicting long-term OS and PFS. Histology reached marginal statistical significance but only for PFS. When those variables were entered in a multivariate analysis only radical resection (P = 0.00142 and 0.0001) resulted a significant factor for predicting long-term OS and PFS, while the use of RT reached a marginal statistical significance, but only for PFS (P = 0.05). Children who had the tumour completely resected did significantly better than all the others who had less than a complete resection, with a 10-year OS and PFS for the two groups of patients of 69.8% (CI 53-86.5%) and 57.2% (CI 40.3-75%) and of 32.5% (CI 8.5-57.6%) and 11.1% (0-24.4%), respectively. These findings suggest that, for childhood EPD, radical resection should be pursued as much as reasonably possible. Thus, it seems justified proposing for future trials, patient stratification by entity of surgical resection.

Adolescent↗
PubMed1997

Endovascular treatment of pial AVMs: technical options, indications and limits in pediatric age patients.

Our study group consisted of 29 patients who underwent endovascular treatment for the presence of pial AVMs. The patients were treated with various embolization methods including "-free flow" embolization (2 cases); embolization with suture threads (2 mm long micro-emboli: 17 cases) and embolization with acrylic glue (10 cases). There were significant angio-architectural and AVM location differences between the pediatric and the adult patient groups. In pediatric patients, the more frequent AVMs were of the mono or few-pedunculated type, then simple direct fistulas and high-flow fistulous-plexiform AVMs and giant infra-tentorial or deep-seated malformations. In mono or few-pedunculated AVMs, the elected treatment was acrylic glue followed by radio-surgery achieving definitive cure in 3 cases. In direct AVFs and elevated flow AVMs, embolization with suture and acrylic glue offered definitive results. Treatment for infra-tentorial and deep-seated AVMs presented the greatest difficulty in pediatric patients. In two of them, embolization with glue enabled radiosurgery (giant cerebellar AVMs). Our experience did not confirm that current endovascular techniques provide definitive treatment in extensive, deep-seated AVMs. Each treatment, in children more so than in adults, requires a risk/benefit evaluation of the method taking into account the natural history data.

Adhesives↗
PubMed1997

Stereotactic radiosurgery for the treatment of arteriovenous malformations in childhood.

BACKGROUND: The main techniques and results in stereotactic radiosurgical treatment of endocranial AVM's are described and compared. The authors also report their preliminary experience in the treatment of 6 consecutive pediatric patients with intracerebral vascular malformations using gamma knife (GK) radiosurgery. METHODS: The various stereotactic radiosurgery methods currently used (charged-particle beam, modified linear accelerator, and GK) are described. At the Department of Neurosurgery in Verona, from February 1993 to February 1996, stereotactic GK radiosurgery was performed on 721 patients, including 20 of pediatric age (3%). Of the 78 AVMs, 7 (9%) were diagnosed in children. One patient was lost at follow-up. Among the remaining 6 children, there were 3 males and 3 females with a mean age of 12.3 years (range, 5-16 years). Treatment general anesthesia was needed only in 1 case. The AVM volume was always less than 10 cc. After completion of the procedure, children were discharged from the hospital the following day. RESULTS: The follow-up period ranged from 4 months to 29 months (median 18.8 months). The angiographic confirmed total obliteration is used as the end point of an AVM treated radiosurgically, and usually requires 2 to 3 years. All the patients are alive; four of the treated children are neurologically normal and one patient has clinically improved to a normal neurological status. The sixth patient has fixed neurological deficits that existed prior to treatment. Among the three cases with a follow-up period of over 2 years, complete obliteration has been angiographically confirmed in 2 patients and subtotal in 1 patient. In the three remaining patients with follow-up periods less than 2 years, serial MR images suggest subtotal obliteration in 2 cases and no significant change in one patient who had undergone treatment within the current year. To date, neither persistent GK radiosurgery-related complications nor bleeding following stereotactic radiosurgery has been described. CONCLUSIONS: The review of literature and our preliminary results suggest that also in children, as in adults, the use of stereotactically delivered irradiation represents a safe and effective technique obtaining complete obliteration of AVMs previously considered surgically inaccessible due to their location and poor response to resection and/or embolization.

Adolescent↗
PubMed1996

The structure of a complex of human 17beta-hydroxysteroid dehydrogenase with estradiol and NADP+ identifies two principal targets for the design of inhibitors.

BACKGROUND: The steroid hormone 17beta-estradiol is important in the genesis and development of human breast cancer. Its intracellular concentration is regulated by 17beta-hydroxysteroid dehydrogenase, which catalyzes the reversible reduction of estrone to 17beta-estradiol. This enzyme is thus an important target for inhibitor design. The precise localization and orientation of the substrate and cofactor in the active site is of paramount importance for the design of such inhibitors, and for an understanding of the catalytic mechanism. RESULTS: The structure of recombinant human 17beta-hydroxysteroid dehydrogenase of type 1 (17beta-HSD1) in complex with estradiol at room temperature has been determined at 1.7 A resolution, and a ternary 17betaHSD1-estradiol-NADP+ complex at -150 degrees C has been solved and refined at 2.20 A resolution. The structures show that estradiol interacts with the enzyme through three hydrogen bonds (involving side chains of Ser142, Tyr155 and His221), and hydrophobic interactions between the core of the steroid and nine other residues. The NADP+ molecule binds in an extended conformation, with the nicotinamide ring close to the estradiol molecule. CONCLUSIONS: From the structure of the complex of the enzyme with the substrate and cofactor of the oxidation reaction, the orientation of the substrates for the reduction reaction can be deduced with confidence. A triangular hydrogen-bond network between Tyr155, Ser142 and O17 from estradiol probably facilitates the deprotonation of the reactive tyrosine, while the conserved Lys159 appears not to be directly involved in catalysis. Both the steroid-binding site and the NADPH-binding site can be proposed as targets for the design of inhibitors.

Amino Acid Sequence↗
PubMed1996

Molecular analysis of mixed infection with hepatitis C virus and human immunodeficiency virus in a patient infected simultaneously.

A case of simultaneous infection with HIV and HCV characterized by a rapidly progressive clinical course was studied retrospectively over 3.5 years. Molecular analysis indicated interference between HIV and HCV and between HCV subtypes 1a and 1b. An ineffective immune response was suggested by the persistence and sequence conservation of the HCV HVR1 variants isolated during the follow-up.

AIDS-Related Opportunistic Infections↗
PubMed1996

Familial cavernous hemangioma with atypical neuroimaging.

Three members of the same family were studied, all of whom had multiple intracerebral cavernous angiomas for which a dominant autosomal inheritance was hypothesised. The proband suffered from headaches, and physical examination revealed evident right hemiparesis. The second case started with a hemorrhagic cerebral stroke and the third was asymptomatic on neurological examination. Nuclear magnetic resonance (NMR), performed in two of the three cases, showed lesions whose number and extent were not radiologically characteristic of cavernous angioma. A cerebral biopsy of the proband enabled the diagnosis to be made. Despite the recent introduction of NMR, the nosological classification of familial forms can be difficult when the radiological lesions are atypical. In such cases, cerebral biopsy is not only a valid diagnostic aid, but is also indispensable for obtaining adequate genetic information.

Brain↗
PubMed1995

Quantification of hepatitis C virus RNA by competitive amplification of RNA from denatured serum and hybridization on microtiter plates.

The direct detection of hepatitis C virus (HCV) RNA by PCR is widely used to determine the presence of circulating virions. The most relevant limit of this approach is the lack of quantitative information about the viral titer. We report a technique of competitive amplification allowing the estimation of HCV RNA copy number in biological samples. We constructed a standard competitive RNA template containing only two point mutations compared with its wild-type counterpart. The competitor was added in titrated amounts to the target RNA, and the mixture was then reverse transcribed and amplified in the same reaction tube. The relative amounts of target and competitor were determined by differential hybridization on microtiter plates with nonradioactive probes. The evaluation of HCV RNA titer required a single coamplification with the competitor and could be read from a standard curve. Furthermore, this method proved suitable for amplification of HCV RNA directly from serum, thus avoiding the intrinsic variability of the RNA extraction step.

Base Sequence↗
PubMed1993

Selection of T lymphocytes in two rheumatoid arthritis patients defines different T-cell receptor V beta repertoires in CD4+ and CD8+ T-cell subsets.

To study the selective pressures responsible for the expansion of T cells in rheumatoid arthritis, we constructed cDNA mini-libraries from purified CD4+ and CD8+ T cells prepared from peripheral blood and from synovial fluids of two rheumatoid arthritis patients. Comparison of these libraries by hybridization with specific probes indicated that V beta 2 and V beta 8 transcripts are selectively enriched in the CD4+ synovial fluid lymphocyte population, while V beta 4 was over-represented among both the CD4+ and CD8+ subsets. The enrichment of V beta 14 and V beta 17 observed in synovial fluid T cells of one patient was, however, selectively confined to the CD8+ T-cell subpopulation. Sequence analysis of several V beta 2, V beta 4 and V beta 8 clones, derived from CD4+ cells, revealed a high degree of heterogeneity in the V beta-D beta-J beta junctions, while a more biased utilization of J segments and a more restricted junctional heterogeneity were observed in V beta 4, V beta 14 and V beta 17 clones derived from CD8+ cells. These data suggest that the disease may be induced by the initial activation of a rather heterogeneous population of T-helper cells that are later responsible for the expansion of a more restricted pool of highly specific effector lymphocytes.

Amino Acid Sequence↗
PubMed1993

[Cranial fractures during growth. An analysis of the authors' personal cases and therapeutic management of such childhood pathology].

Growing skull fractures are a rare complication of head injury with a dome fracture. The cases described in literature highlight a higher frequency of this pathology in children under than over three years of age. The authors describe 4 personal cases, underlying the clinical, diagnostic and therapeutic aspects. The aetiological hypothesis of a dural tear and its anatomic-pathological evolution are investigated. The surgical technique of dural and bony repair is also discussed. The authors conclude that this complication must be recognized early in order to obtain very good results after surgical therapy.

Accidental Falls↗
PubMed1992

Non-radioisotopic methods for DNA probes.

We have recently developed a new colorimetric method, DNA enzyme immunoassay (DEIA), for detecting specific hybrids of complementary nucleic acids. This technology is based on an antibody that selectively recognizes double, but not single-stranded DNA. The molecule does not react with a specific probe immobilized on microwells through an avidin-biotin bridge, nor with non-specific amplified sequences, since they are removed by washing. The antibody reveals the hybridization event, independently of the DNA sequences and, for this reason, the method is broadly applicable and extremely versatile. Although we chose a format based on the immobilization of the probe through an avidin-biotin interaction, DEIA assay can also be applied to other analytical schemes that do not require any modification of the probe. Most importantly, the test has an ELISA format and is rapid and convenient for processing large numbers of samples. This technology has been applied, in our laboratory, to different areas, including virology, genetic and basic immunology. The DEIA assay has been successfully used to detect the presence of hepatitis B (HBV), hepatitis C (HCV) and hepatitis delta virus (HDV) sequences in serum of patients, to discriminate different HLA alleles, to identify mutations in the Cystic Fibrosis gene, and to investigate the role of the T cell receptor in some immunological diseases. The results obtained in all our experiments demonstrated that the advantages offered by the assay do not penalize its analytical performance as compared to conventional Southern blot.

Colorimetry↗
PubMed1991

Spontaneously healed vein of Galen aneurysms. Clinical radiological features.

Vein of Galen aneurysms demonstrate a high tendency to thrombose, as extensive thrombophlebitis of the dural sinuses and deep venous system occurs frequently. This may be explained by the frequent detection of venous anomalies and retention of embryonic venous patterns such as the median prosencephalic vein. Twenty-one cases were reviewed (19 from the literature, 2 of our own cases): no typical syndrome for thrombosed aneurysm of the vein of Galen could be found; therefore, a preliminary diagnosis of clotted vein of Galen aneurysm was made in only half the cases. In all the remaining ones, pineal or III ventricle masses were suspected. Nevertheless, crescentic rimlike calcifications in the region of the vein of Galen can be found in 50% of cases. Only in half of the cases did angiography demonstrate the malformation filled by contrast medium, while in the remaining cases not only the aneurysm but also the deep Galenic venous system failed to opacify. Computed tomography and magnetic resonance scans demonstrated masses with high density/intensity values, with varying degrees of calcification. Knowledge of this pathological entity is important in order to avoid unnecessary surgical procedures.

Adolescent↗
PubMed1991

Cerebral cavernous malformations (cavernomas) in the pediatric age-group.

Cavernomas are vascular malformations composed of a compact mass of sinusoidal-type vessels that are immediately contiguous with one another and have no intervening parenchyma. Cavernous malformations were previously held to be a rare pathology occurring predominantly in adults. New neuroradiological techniques such as computed tomography (CT) and magnetic resonance imaging (MRI) demonstrate, on the contrary, that these lesions are also more frequent during childhood than was previously thought. In our institution we observed 17 cases of cavernous malformations in patients aged between 18 months and 16 years, 16 of whom were diagnosed after 1982. In 4 of these cases there was a documented familial history; in 2 multiple malformations were present. The most common site was the subcortical frontal region, but in 1 case the malformation was located in the pineal region. The most frequent (in 12 cases) initial symptom was hemorrhage, with the characteristics of an intracerebral hematoma. In 4 cases the initial symptom consisted of epileptic fits and 2 of these patients subsequently suffered hemorrhage. In one case the symptoms observed were those of an expansile process. All our patients underwent cerebral angiography and only in 1 case did this show a vascular abnormality. CT, performed in 16 patients, gave positive results in all cases. MRI, performed in 12 patients, gave highly significant images in all cases. Radical surgical removal of the malformation was performed in 15 of the 17 patients, and the results can be considered excellent in the majority of cases. Cavernous malformations are, therefore, more frequent lesions than had previously been thought, especially in pediatric patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Irreversible respiratory failure in an achondroplastic child: the importance of an early cervicomedullary decompression, and a review of the literature.

The authors report the case of a girl with achondroplasia suffering from a progressively worsening hypotonic quadriparesis. CT scan showed slight dilatation of ventricular and subarachnoid spaces, with well-defined evidence of cortical sulci and gyri. This aspect was compatible with the diagnosis of macrocrania and megalencephaly (CP being 51 cm). The foramen magnum was narrowed, the transverse diameter measuring 15 mm and the 50th percentile being, for age, 26 mm. Somatosensory evoked potentials (SEPs) revealed bilaterally prolonged interpeak latencies Erb-N13, slowing of central conduction time N13-N20 from right median nerve stimulation, and block from left median nerve. The suspicion of cervicomedullary compression was confirmed by MRI, showing a very marked stenosis with compression exerted by the odontoid process. Further, a stenotic cervical canal and optic nerves verticalization were manifest. The patient underwent neurosurgical decompression by suboccipital craniectomy and cervical-C1 laminectomy. In spite of treatment, both neurologic and respiratory problems (rapid, shallow and almost abdominal breathing) were unchanged. The girl died 4 1/2 months later. The authors emphasize the important role of SEPs in detection of cervicomedullary compression in achondroplastic children and also stress the necessity of an early surgical treatment as the only condition for possible clinical improvement and/or full recovery.

Achondroplasia↗
PubMed1991

DNA enzyme immunoassay: a rapid and convenient colorimetric method for diagnosis of cystic fibrosis.

Genetic analysis of inherited diseases has been greatly facilitated by new approaches, involving genomic DNA amplification by the polymerase chain reaction (PCR), followed by hybridization with wild type-specific or mutation-specific oligonucleotide (MSO) probes. The main advantage of these methods is that they allow easy detection of point mutations starting from minimal amounts of biological materials. These techniques, however, require procedures which are not well suited to large-scale screening or use in routine laboratories. The development of dedicated kits to perform these tests efficiently in clinical laboratories is an important current issue. We developed a new non-radioisotopic assay to reveal specifically DNA-DNA hybrids between amplified DNA and MSO probes, and applied it to the detection of two mutations causing cystic fibrosis. The detection of hybrids is achieved by means of an anti double-stranded DNA antibody, in a format which is designed as a colorimetric assay resembling a common enzymatic immunoassay (EIA). The assay detects the hybridization event, independent of the nucleic acid sequences involved in the formation of the specific hybrids, and can be used with any combination of target DNA and probes. Therefore, this test represents a significant improvement for the clinical use of the polymerase chain reaction in the diagnosis of inherited diseases.

Antibodies, Monoclonal↗
PubMed1990

Medical treatment of senile cataract: clinical investigation of bendazac-lysine using objective and subjective methods.

A modified Zeiss slit lamp coupled with a digital image-processing system was used to evaluate objectively changes in lens transparency over 1 year at 4-month intervals in 150 eyes of 92 patients affected by early senile cataract. A total of 59 patients were treated daily with 1.5 g bendazac-lysine, and 33 patients constituted the control group. At follow-up, visual acuity was also tested using Snellen letter charts at variable contrast to provide an additional parameter closer to traditional methods. Results indicate that the minimal angle of resolution at 10% contrast (MAR10) and the mean gray-level value of the lens image obtained by retroillumination (MLR) are sensitive to early changes in lens transparency. Using MAR10 as a parameter, the control group showed a significant, progressive worsening of the lens status over 12 months, whereas the treated group exhibited no significant changes. MRL indicated the same behaviour as MAR10, although lens damage was detected later in the control group. The results show that bendazac-lysine may delay the formation of lens opacities.

Aged↗
PubMed1990

Transient focal leukoencephalopathy following intraventricular methotrexate and cytarabine. A complication of the Ommaya reservoir: case report and review of the literature.

A 14-year-old boy, suffering from acute lymphoblastic leukemia with meningeal involvement, was treated with intraventricular methotrexate and cytosine arabinoside, administered via an Ommaya reservoir (OR). Three months later, right occipital headache, vomiting, and lethargy appeared. Cerebrospinal fluid specimens showed increased proteins and a right frontal slow-wave focus was evident on the EEG recording. The computed tomography scan revealed white matter hypodensity within the right frontal and rolandic regions. After injection of medium contrast, an abscesslike hyperdensity appeared, surrounding both a well-placed cannula tip and the right frontal horn of the lateral ventricle. Brain swelling and shift signs were also evident. Nine cases of focal methotrexate leukoencephalopathy have been previously reported, and in six of these there was a misplaced OR cannula tip. The focal methotrexate leukoencephalopathy seems to be related to the neurotoxicity of the drugs administered, and may also exist with a well-placed OR cannula tip. Immediate removal of the catheter may be associated with a benign evolution.

Adolescent↗