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Biomedical subjects

V David

Publications and source records attributed to V David.

210 records · Page 12Linked to original sources
PubMedDate not supplied

[Comparison between estimates of radiological workload].

OBJECTIVE: To comparise three methods for assessing the productivity of radiological services: a) simple count of radiological examinations, b) method proposed by SNR-SAGO-SIRM, c) method used by Regione Emilia Romagna (RER) to evalutate the characteristics of these methods and to find a common method of estimate. MATERIAL AND METHODS: On the radiological examinations performed at our unit over a period of 12 months were recorded. The different types of examinations were clustered into five homogenous groups (general radiology, ultrasound, barium examinations, CT, MRI). The data were assessed by a) number of examinations/hour per radiologist, b) score/hour according to the SNR-SAGO-SIRM method and c) score/hour according to the RER method, and then compared for the percentage of the single aggregates. RESULTS: a) The total number of examinations was 26,776 with 40% being accounted for by general radiology; mean numbers of examinations our ranged from 2.43 (August) to 4.20 (March). b) The total score according to the SNR-SAGO-SIRM method was 67,054. The radiologist weight per hour ranged from 6.37 (August) to 9.67 (May). Ultrasound was the most relevant examination in the unit accounting for 43% of total weight. c) The total score according to the RER method was 1,850,780. The radiologist weight per hour ranged from 159 (August) to 316 (April). CT was the most relevant examination (51% of total weight). CONCLUSION: According to the simple count of examinations, general radiology and ultrasound were the most relevant examinations together accounting for 75% of examinations, i.e. 40% and 35% respectively, whereas by SNR-SAGO-SIRM standards the two techniques represent 19% and 45% respectively. The simple count method therefore fails to give adequate weight to technologically advanced imaging technique. The SNR-SAGO-SIRM method adequately takes into account the combination of patient-number and patient weight. The RER method gives excessive weight costly technology as it considers the total weight of the examination and not only the radiologist's activity.

Costs and Cost Analysis↗
PubMedDate not supplied

99MTC [13LEU] bombesin and a new gamma camera, the imaging probe, are able to guide mammotome breast biopsy.

UNLABELLED: A pilot study has been carried out in order to verify the feasibility of scintigraphic driving for breast biopsy. A new high resolution (HR) gamma ray detector, the imaging probe (IP), and 99mTc [13Leu] Bombesin (99mTc BN), have been used to drive a mammotome biopsy needle after having fused radioisotope with digital X-ray images. IP is a mobile, high resolution, miniaturised gamma camera, whose field of view is one inch and whose spatial resolution is 2 mm. 99mTc BN is a new radiotracer derived from the well-known peptide, that has already shown very high sensitivity in detecting breast cancer. PATIENTS AND METHODS: Five patients very suspicious for breast cancer were studied. 185 MBq of 99mTc BN were i.v. injected and dynamic prone scintimammography was performed for 20 minutes with a conventional large field of view gamma camera. IP was matched with the biopsy system and digital X-ray device of a mammotome system, in order to fuse images and to use the mammotome pointer indifferently on X-ray, scintigraphic and fused images. Biopsy samples were counted and weighed: uptake was expressed as counts sec-1 gr-1. Samples were classified into high, intermediate and low uptake. Conventional histological assessment was blindly performed on the samples. RESULTS: All of the patients showed cancer. The T categorisation was T1a for two cancers and T1b for 3. Dynamic prone scintimammography with conventional gamma camera, as well as HR scintigraphy with IP showed spots of 99mTc BN uptake. Maximal mismatch between X-ray lesions and of hot spots imaged with IP before mammotome scintigraphy was 3.4 mm. All the high uptake samples and all but two of the intermediate uptake samples showed cancer, whereas histology found malignant tissue in only 2 out of the 8 low uptake samples. CONCLUSION: 99mTc BN confirms its high sensitivity in detecting breast cancer. IP is able to drive or co-drive breast biopsy when used with appropriate radiopharmaceuticals.

Aged↗
PubMedDate not supplied

[Genetic study of holoprosencephaly].

Holoprosencephaly (1/16,000 live births; 1/250 conceptuses) is a complex brain malformation resulting from incomplete cleavage of the prosencephalon, affecting both the forebrain and the face. Clinical expressivity is variable, ranging from a single cerebral ventricule and cyclopia to clinically unaffected carriers in familial dominant autosomic holoprosencephaly. The disease is genetically heterogeneous but additional environmental agents also contribute to the aetiology of holoprosencephaly. In our cohort of 143 patients, 28 heterozygous mutations were identified: 15 in the Sonic hedgehog gene (SHH), 6 in ZIC2, 5 in SIX3, and 2 in TGIF. Functional tests have been set up to validate the significance of SHH amino acids replacements. Novel phenotypes associated with a mutation have been described such as abnormalities of the pituitary gland and corpus callosum, colobomatous microphthalmia, choanal aperture stenosis and isolated cleft lip. This study confirms the great genetic heterogeneity of the disease, the important phenotypic variability in holoprosencephalic families, and the absence of evident genotype-phenotype correlations.

Cohort Studies↗
PubMedDate not supplied

[Role of MR cholangiopancreatography in the evaluation of biliary disease].

PURPOSE: To evaluate the diagnostic accuracy of MR cholangiopancreatography (MRCP) in biliary tree patology in comparison with percutaneous transhepatic cholangiography (PTC), endoscopic retrograde cholangiopancreatography (ERCP) and surgical findings. MATERIALS AND METHODS: Forty-six patients , with clinical and laboratory findings suggestive of biliary tree pathology, and after an abdominal US, underwent MRCP with a 1.5 T superconductive magnet equipped with a phased-array body coil. MR exam was performed with baseline sequences for the examination of the upper abdomen, followed by specific MRCP sequences and, in cases of suspected neoplastic disease, completed with abdominal sequences after a bolus injection of paramagnetic contrast. RESULTS: MRCP showed normal findings in 16/46 patients, biliary duct dilatation in 25/46 patients (7 choledocolithiasis, 10 benign obstructions and 8 neoplastic stenoses) and stenoses without dilatation of biliary tree in 5/46 patients. In 25 patients with biliary duct dilatation, CPRM correctly identified the level of in 100% of patients (25/25) and the nature in 88% of patients (22/25). In 5 patients with stenosis without dilatation of biliary tree, CPRM identified 2 true positives (sclerosing cholangitis), 2 false positives and 1 patient is still in follow-up. CONCLUSIONS: In our experience MRCP proved to be highly accurate as fundamental diagnostic step in patients with clinical and laboratory findings suggestive of biliary disease. The workload of ERCP, invasive method with risk of complications, in the diagnosis stage could therefore be reduced and its use be reserved for therapeutic indications.

Adult↗
PubMedDate not supplied

Immunoactive products of human placenta (III): Characterization of an inhibitor affecting lymphocyte proliferation.

We have investigated the effects of supernatants from human placenta explant cultures on lymphokine dependent T cell proliferation using mainly the CTLL-2 reference murine cell line. A profound, dose dependent, inhibition of both IL-2 and IL-4-dependent cell proliferation was observed. In addition, supernatants from human placental cultures inhibited B cell proliferation, IL-5-driven proliferation of B13 cells, and IL-6-induced proliferation of 7TD.1. Conversely, the supernatants from human placental cultures enhance the growth of human embryonic fibroblasts. Characterization of the material by HPLC yielded a 68-70 kDa peak at pH 7.4, but the peak activity was at a smaller molecular weight (20-25 kDa) if pH 2.9 acetic acid, KC1 buffer was used. The same fractions were inhibitory for IL-2 and IL-4 driven proliferation of CTLL-2 cells. We conclude that the substances tested are acting as a general growth inhibitor for lymphocytes.

Animals↗
PubMedDate not supplied

[Molecular genetics of hemochromatosis].

Haemochromatosis is an inherited disorder of iron metabolism characterized by a general iron over loading. Without diagnosis and early treatment, it is a serous and potentially fatal disease by cardiac failure or hepatocellular carcinoma in particular. Gene prevalence was estimated at 0.06 in Brittany, so that haemochromatosis may be the most common genetic disease in this area. The biochemical defect of the disease is unknown; only one fact is well established: the iron absorption through duodenal mucosa is excessive. However, we don't know if it is a primary event. The gene is also unknown but in 1975 it was located on the short arm of chromosome 6, closely linked to the HLA class I region, less than 1 cM from HLA-A. None of the genes coding for the known iron proteins could be the haemochromatosis gene because of their chromosomal localization. In order to locate this gene with precision, we have used a reverse genetic approach now called positional cloning. Characterization of new polymorphic markers and linkage disequilibrium analysis have led us to locate the gene within a 350 kb region around HLA-A. We have then searched for all the structural genes in this region. Seven new genes have been so identified and located with precision. A structural analysis of these genes was undertaken to find an eventual abnormality in patients.

Chromosome Inversion↗
PubMedDate not supplied

[Genetic hemochromatosis].

Haemochromatosis is the most common genetic disease in individuals of Northern European origin. This disorder of iron metabolism, for which the molecular basis remains poorly understood, is characterized by an excessive absorption of dietary iron through the duodenal mucosa. Progressive iron loading of parenchymal organs results in the mid-life onset of clinical complications, and patients may succumb to cardiac failure and/or hepato-carcinoma. But patients who undergo early diagnosis and phlebotomy treatment before the development of organ damage have a normal life expectancy. The haemochromatosis gene was recently isolated and encodes a HLA class I related protein. A missense mutation (C282Y) in the homozygous configuration was observed in more than 92% of the patients. So diagnosis and genetic counselling are getting modified by this direct genotyping test.

Genetic Counseling↗