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Biomedical subjects

P Pavone

Publications and source records attributed to P Pavone.

At least 37 records · Page 2Linked to original sources
PubMed2001

Phonon dispersion curves in wurtzite-structure GaN determined by inelastic x-ray scattering.

We have investigated the lattice dynamics of a wurtzite GaN single crystal by inelastic x-ray scattering. Several dispersion branches and phonons at high-symmetry points have been measured, including the two zone-center Raman- and infrared-inactive silent modes. The experiments have been complemented by ab initio calculations. They are in very good agreement with our measurements, not only for phonon energies, but also for scattering intensities, thus validating the correctness of the eigenvectors. Other phenomenological and ab initio theories exhibit significant differences.

Journal Article↗
PubMed2001

Primary effusion lymphomas in AIDS: CT findings in two cases.

Primary effusion lymphomas represent an unusual subset of AIDS-related non-Hodgkin's lymphomas. They are associated with herpes virus 8 and Epstein-Barr virus and characterized by predominant involvement of the serous body cavities (pleura, pericardium, peritoneum) as lymphomatous effusion without any identifiable tumour mass. We report herein CT findings in two patients with primary effusion lymphoma emphasizing the possible neoplastic nature of a pleural effusion in a patient with AIDS.

Adult↗
PubMed2001

Improving the results of virtual colonoscopy: what the future will bring.

Several studies show the possibility of using virtual colonoscopy in radiologic routine. To understand what its future holds, a deep insight into the techniques and pitfalls is mandatory. Currently, patient preparation and insufflation methods have to be improved because they represent the main source of pitfalls. Acquisition techniques currently provide only morphologic information, which is inadequate in the case of flat lesions. Functional information is needed but not yet available. Although the development of postprocessing techniques during the past few years has been rapid, virtual colonoscopy cannot yet be proposed as a screening technique. State-of-the-art technology, however, allows us to imagine that in the near future it will become a tool suitable for routine application.

Colonic Neoplasms↗
PubMed2001

From maximum intensity projection to volume rendering.

Three-dimensional medical images can be generated with a variety of computer algorithms from computed tomography and magnetic resonance data sets. The most commonly used techniques are maximum intensity projection (MIP) and shaded surface display (SSD). Recently, volume rendering (VR) has become available on dedicated workstations, providing the possibility of interaction with data sets. All 3D rendering techniques represent a volume of data in 1 or more 2-dimensional (2D) planes, conveying the spatial relationships inherent in the data with the use of visual depth cues. Techniques and artefacts regarding MIP, SSD, and VR are described here, along with several models of clinical application.

Algorithms↗
PubMed2001

Lack of progression of brain atrophy in Aicardi-Goutières syndrome.

Aicardi-Goutières syndrome is a severe and progressive familial encephalopathy that is characterized by acquired microcephaly, intracranial calcification (mainly of the basal ganglia), signs of white matter disease, and chronic lymphocytosis with elevated levels of interferon-alpha in the cerebrospinal fluid in the absence of other evidence of infection. Although the degree of calcification and the severity of brain atrophy are variable, typically the brain lesions appear to progress on successive examinations. In this article a 4-year-old male patient with Aicardi-Goutières syndrome who manifested the typical neurologic signs of the disease was re-evaluated. The evaluation revealed, on successive cranial computed tomography and magnetic resonance imaging scans, increasing calcification with remarkable reduction of brain atrophy. To the best of our knowledge, there is only one previously mentioned study of a 4-year-old female patient with progressive features of Aicardi-Goutières syndrome, including intracranial calcification, who displayed a lack of progression of brain atrophy at MRI scan.

Atrophy↗
PubMed2001

Three-dimensional contrastless varicography by spiral computed tomography.

OBJECTIVE: to report and discuss preliminary results obtained in varicose limbs by means of a volume rendering (VR)-computed tomography (CT) technique without contrast medium injection. MATERIALS AND METHODS: VR-CT and duplex sonography (US) were performed to visualise the superficial veins of the lower extremity in eight healthy and 12 varicose limbs. RESULTS: VR-CT clearly demonstrated the 3D arrangement of the superficial veins and visualised small sized veins which were not visible at US examination. CONCLUSIONS: VR-CT is not suitable for routine evaluation of varicose limbs. VR-CT 3D reconstructions may be useful in the evaluation of atypical varicosis. Further studies are needed to define the role of VR-CT in deep venous disease.

Adult↗
PubMed2001

Fetal nucleated red blood cell counts in peripheral blood of mothers bearing Down syndrome fetus.

Currently, prenatal detection of Down syndrome and other most common aneuploidies relies on invasive procedures such as amniocentesis and villocentesis, and on non-invasive screening tests such as second trimester maternal serum screening (Triple test), and first trimester screening (ULTRA-screen). However, it well known that invasive techniques carry a small risk of fetal loss, while both Triple test and ULTRA-screen are not diagnostic, may miss from 15 - 40 % of cases of Down syndrome, in addition to having a 5 - 8 % rate of false-positives. We now report clear evidence that the number of fetal nucleated red blood cells (FNRBCs) in the maternal circulation is remarkably higher in pregnant women carrying aneuploid fetuses, especially in cases of Down syndrome. These results are in agreement with the findings of other investigators using different methods, and suggest that the number of FNRBCs present in the maternal blood sample could be used as additional marker, in concert with existing screening tests, to improve non-invasive detection of Down syndrome, and other most common aneuploidies.

Adult↗
PubMed2001

Hemihydranencephaly: case report and literature review.

Hydranencephaly is a severe brain condition characterized by complete or almost complete absence of cerebral cortex with preservation of meninges, basal ganglia, pons, medulla, cerebellum, and falx. It has been ascribed to different causes (infections, irradiations, fetal anoxia, medications, twin-twin transfusion), all leading to vascular disruption. Hemihydranencephaly is an extremely rare condition in which the vascular anomaly is unilateral. We report on a patient who was suspected to have hydrocephalus in utero; a brain magnetic resonance imaging scan showed left-sided hydranencephaly with preservation of basal ganglia. The patient developed signs of right hemiparesis but notably has only mild language delay. The available literature on hemihydranencephaly is reviewed.

Brain↗
PubMed2001

Holoprosencephaly (lobar form) associated with bilateral vocal cord palsy.

There have been many causes associated with bilateral vocal cord palsy, both congenital and perinatal. Until now, the main congenital causes of bilateral vocal cord palsy have been associated with meningomyelocele, Arnold-Chiari malformation, and hydrocephalus. We report a patient with bilateral vocal cord palsy associated with the lobar form of holoprosencephaly. In this case, bilateral vocal cord palsy was caused by the disruption of the cortical laryngeal motoneurons. Neonatal stridor must be carefully evaluated by the neonatologist to exclude severe cerebral anomalies.

Female↗
PubMed2001

Long-term survival in a child with arthrogryposis multiplex congenita and spinal muscular atrophy.

Spinal muscular atrophy type 0 is a severe form of spinal muscular atrophy that is usually fatal in the first months of life. These children present with arthrogryposis multiplex congenita and respiratory compromise. We describe a child with spinal muscular atrophy and arthrogryposis multiplex congenita who has had a much better course and is alive without ventilator support at age 6 years. This case illustrates that the prognosis for spinal muscular atrophy and arthrogryposis multiplex congenita cannot always be predicted with certainty.

Arthrogryposis↗
PubMed2000

Colobomatous microphthalmia, microcephaly with cerebellar hypoplasia: association or new syndrome?

We report on a 3.5-year-old girl with microcephaly, microphthalmia, coloboma of the iris, mild developmental delay, and other minor anomalies. Neuroimaging showed marked cerebellar and vermian hypoplasia. This condition has not been described previously and is discussed in the context of the "micro syndrome," together with other similar syndromes. Our case highlights the heterogeneity of the "microphthalmia plus brain malformations" group of patients.

Adult↗
PubMed2000

Diabetes insipidus in neurobrucellosis.

Brucellosis is an infection due to Brucella species and is characterized by acute febrile illness, chilly sensations, sweats, weakness, generalized malaise, body aches and headache. The involvement of the nervous system is rare. A few cases have been reported with symptoms and sign of optic neuritis, meningoencephalitis, meningomyelitis and cranial nerve palsy. We report a case with culture proven neurobrucellosis who presented with diabetes insipidus along with systemic signs. Neuroimaging revealed multiple lesions in brain parenchyma, including the suprasellar region. Both diabetes and suprasellar lesions improved markedly with specific antibiotic therapy.

Brain↗
PubMed2000

Arthrogryposis multiplex congenita and pituitary ectopia. A case report.

We report a patient with a form of arthrogryposis multiplex congenita who developed seizures at 4 months of age that proved to be hypoglycemic. Further evaluation of the etiology of hypoglycemia led to the discovery of partial anterior hypopituitarism, with normal posterior pituitary function. Neuroimaging revealed an ectopic neurohypophysis with very small anterior pituitary, the presumed anatomic basis for his endocrine dysfunction. A chance association between the pituitary ectopia and the arthrogryposis cannot be ruled out. However, it is more likely that in the present patient a common genetic mechanism may be the basis for both the arthrogryposis and the pituitary dysfunction.

Abnormalities, Multiple↗
PubMed2000

Diffuse polymicrogyria associated with congenital hydrocephalus, craniosynostosis, severe mental retardation, and minor facial and genital anomalies.

We report an infant boy with an apparently new malformation syndrome. The major anomalies showed by the patient include diffuse polymicrogyria, congenital hydrocephalus, craniosynostosis with severe scaphocephaly, severe mental retardation, intractable epilepsy, and minor facial and genital anomalies. Our review of the literature and two computerized dysmorphology databases found some papers reporting polymicrogyria or lissencephaly associated with craniosynostosis or hydrocephalus. None of the reported patients had a phenotype similar to that of our patient.

Abnormalities, Multiple↗