Comprendre et utiliser le CAD (Aide informatisée au diagnostic) en mammographie

Generalization of breast screening programs requires efficient double reading of mammograms, which allows reduction of false negative interpretations, but it may be difficult to achieve. CAD (Computed Aided Detection) systems are dramatically improving and can now assist in the detection of suspicious mammographic lesions, either suspicious microcalcifications, masses or architectural distortion. Characterization of the lesions is improving as well. CAD mammography might complete or substitute to "human" double reading. The aim of this review is to present the main CAD systems commercially available, review the principles of CAD and discuss the results of CAD mammography. Specifically, the role of CAD within breast screening program, according to the results of recent prospective studies will be discussed.

Characterization and localization of short-specific polygalacturonase in distylous Turnera subulata (Turneraceae)

We describe for distylous Turnera subulata a polygalacturonase specific to short-styled plants that is localized to the style transmitting tissue (the tissue through which pollen tubes grow). The polygalacturonase gene is linked to and may be upregulated by the S allele of the distyly locus. Because of its tissue-specific location, the polygalacturonase may be involved in the self-incompatibility response, acting in a complementary or antagonistic manner, or possibly in signalling downstream events. A pollen-specific polygalacturonase was also identified and may be a member of a small multigene family of pollen polygalacturonases. The role, if any, played by the pollen polygalacturonase in distyly, is presently unknown.

Interferon-a2b reduces neo-microvascular density in the 'normal' urothelium adjacent to the tumor after transurethral resection of superficial bladder carcinoma

BACKGROUND

As angiogenesis represents one of the hallmarks of cancer we investigated whether intravesically administered interferon-a (IFN-a2b) reduces neo-angiogenesis in the 'normal' urothelium adjacent to the tumor in patients with superficial bladder carcinoma after complete transurethral resection (TUR) of the tumor.

PATIENTS AND METHODS

In the present study 47 patients after TUR of the tumor were examined. 10 patients (group A) received no further treatment (control group); 37 patients (group B) received intravesical treatment with IFN-a2b. The instillations started within 7 days after TUR, were performed weekly for 2 months, twice a month for the next 4 months, and thereafter monthly for 6 more months. Cold cup biopsies were taken before TUR of the transitional cell carcinoma (TCC): from the tumor (T), near tumor (NT) and from normal epithelium (N). Cold cup biopsies 'near tumor', were also taken during follow-up cystoscopy (C1, C2, and C3) 2, 6, and 12 months after TUR, respectively. Angiogenesis was estimated by counting the microvessels detected with CD31 immunostaining.

RESULTS

Significant differences of microvascular density (MVD) between patients of group A and B appear after TUR (p < 0.005, Kruskal-Wallis and Wilcoxon test). The MVD difference was maximal 6 months after TUR (C2(A)-C2(B), second cystoscopy) and measured at 12.17 microvessels/ mm(2) (26.2%).

CONCLUSION

Our results show that the intravesical administration of IFN-a2b after TUR significantly decreases the angiogenic potential of the 'healthy' urothelium adjacent to the tumor in patients with TCC. This observation could possibly explain, to a certain extent, the mechanism by which IFN-a2b reduces the recurrence rate of primary TCC.

Sedations and analgesia in patients undergoing percutaneous transhepatic biliary drainage

AIM

To present our experience using intravenous sedoanalgesia for percutaneous biliary drainage.

MATERIALS AND METHODS

This study comprised 100 patients, all of whom were continuously monitored [electrocardiogram (ECG), blood pressure, pulse oxymetry] and received an initial dose of 2mg midazolam followed by 0.02 mg fentanyl. Before every anticipated painful procedure, a maintenance dose of 0.01 mg fentanyl was administered. If the procedure continued and the patient became aware, another 1mg midazolam was given. This was repeated if patients felt pain. A total dose of 0.08 mg fentanyl and 7 mg midazolam was never exceeded. Immediately after the procedure, the nurse was asked to evaluate patients' pain score. The patients were asked 3h later to complete a visual 10-degree pain score scale.

RESULTS

The average dose of fentanyl and midazolam was 0.042 mg (0.03-0.08 mg) and 4.28 mg (2-7 mg), respectively. Only one patient recorded the procedure as painful. The scores given by the attending nurse (1-7 points, mean 2.9) correlated well with those given by the patients (1-6 points, mean 2.72). No complications were noted.

CONCLUSION

According to our experience, interventional radiologists practising biliary procedures can administer low doses of midazolam and minimize the doses of fentanyl, without loss of adequate sedation and analgesia.

Damage to intracranial optic pathways in fatal closed head injury in man

Head injury is a leading cause of visual impairment. This is partly due to direct trauma to the eye and optic nerve but much of the damage involves the intracranial optic pathways. We have studied the frequency, distribution and nature of the intracranial lesions of the optic pathways at autopsy in 45 cases of severe closed head injury, and examined the correlation between these post-mortem lesions and the ante-mortem clinical findings. Twenty-four of the patients had been involved in road traffic accidents. The ages ranged from 9 to 88 years (mean 46.4), the Glasgow Coma Score (GCS) on admission ranged from 3 to 15 (mean 5), and the survival time after injury from 2.5 h to15 days (mean 3.3 days). Skull fractures were present in 75.6% of the cases. Histological assessment included the use of immunohistochemistry for beta-amyloid precursor protein (beta-APP) and the microglial marker CD68. Axonal injury of varying severity was demonstrable in all cases, and in 39 (87%) the optic chiasm, tracts or radiations were involved, usually in more than one region. The severity of axonal injury was mild in 11 (24%), moderate in 9 (20%) and severe in 19 (42%) cases. The optic radiation at the level of the trigone of the lateral ventricle was particularly frequently and severely affected. The least affected parts of the intracranial optic pathways were the optic chiasm and the posterior segment of the optic nerve. The severity of injury to the optic pathways did not always reflect severity of axonal injury elsewhere in the brain and correlated poorly with the type of trauma (high- or low-velocity), presence of skull fractures or evidence of raised intracranial pressure (ICP). Of the 39 patients who survived more than 6 h, histological evidence of ischaemic injury to the primary optic cortex was present in 26 (67%) and was severe in 12. We conclude that the visual pathways are affected in a high proportion of patients with fatal closed head injury, nerve fibres in the optic radiations being particularly vulnerable. The findings suggest that damage to the posterior parts of the optic pathways may be under-diagnosed among patients with head injury.

Deregulated expression of c-mos in non-small cell lung carcinomas: relationship with p53 status, genomic instability, and tumor kinetics

Little is known about the status of the mitogen-activating protein kinase pathways in lung cancer. One of the key molecules taking part in these pathways is the product of the c-mos proto-oncogene, which plays an important role in oocyte maturation. In vitro investigations in somatic cells have shown that c-mos expression has opposing effects on the cell cycle, which suggests that this proto-oncogene may represent an important determinant of aberrant cell function (genomic instability and altered kinetics). A recent study suggests that these effects may be p53 dependent. In view of the apparent link between c-mos and p53, we investigated in a series of 56 non-small cell lung carcinomas: a) the status of c-mos; b) its relationship to genomic instability (aneuploidy) and two kinetic parameters of the tumors, proliferation and apoptotic indexes (AI); and c) its association with p53 alterations and their concomitant relationship with the above parameters. We found c-mos overexpression in 27% of the tumors. Expression was higher in stages II/III (34%) than in stage I (17%; P = 0.018). Complete concordance was observed between c-mos overexpression and elevated c-mos mRNA levels. Because c-mos gene amplification was not detected, its deregulated expression may be attributable to increased transcription. Of the c-mos positive [c-mos(P)] cases, 77% were associated with aneuploidy. Sequencing showed two silent mutations and one missense (R-->L) at codon 22, located in a region critical for c-mos stability. In contrast to the findings of some in vitro studies, c-mos(P) tumors had a lower mean AI score than the c-mos negative [c-mos(N)] tumors had, implying that induction of apoptosis may have been defective. Indeed, 86% of the tumors overexpressing c-mos showed p53 alterations. The carcinomas with concomitant alterations of c-mos and p53 [c-mos(P)/p53 positive] had significantly lower AI values (P < 0.001) and were more frequently associated with aneuploidy (P = 0.015) than the c-mos(N)/p53 negative tumors but not the c-mos(N)/p53 positive tumors, which suggests that p53 status is the main determinant of ploidy status and apoptosis in our series. This finding also strengthens the concept that wild-type p53 plays a "safeguard" role in preventing oncogene-mediated activation.

Chondroitin sulphate inhibits connective tissue mast cells

1. Mast cells derive from the bone marrow and are responsible for the development of allergic and possibly inflammatory reactions. Mast cells are stimulated by immunoglobulin E (IgE) and specific antigen, but also by a number of neuropeptides such as neurotensin (NT), somatostatin or substance P (SP), to secrete numerous pro-inflammatory molecules that include histamine, cytokines and proteolytic enzymes. 2. Chondroitin sulphate, a major constituent of connective tissues and of mast cell secretory granules, had a dose-dependent inhibitory effect on rat peritoneal mast cell release of histamine induced by the mast cell secretagogue compound 48/80 (48/80). This inhibition was stronger than that of the clinically available mast cell 'stabilizer' disodium cromoglycate (cromolyn). Inhibition by chondroitin sulphate increased with the length of preincubation and persisted after the drug was washed off, while the effect of cromolyn was limited by rapid tachyphylaxis. 3. Immunologic stimulation of histamine secretion from rat connective tissue mast cells (CTMC) was also inhibited, but this effect was weaker in umbilical cord-derived human mast cells and was absent in rat basophilic leukemia (RBL) cells which are considered homologous to mucosal mast cells (MMC). Oligo- and monosaccharides were not as effective as the polysaccharides. 4. Inhibition, documented by light and electron microscopy, involved a decrease of intracellular calcium ion levels shown by confocal microscopy and image analysis. Autoradiography at the ultrastructural level showed that chondroitin sulphate was mostly associated with plasma and perigranular membranes. 5. Chondroitin sulphate appears to be a potent mast cell inhibitor of allergic and nonimmune stimulation with potential clinical implications.

c-mos immunoreactivity is an indicator of good prognosis in lung cancer

AIMS

Reports concerning the expression of cytoplasmic components of the mitogen-activating protein kinase (MAPK) pathway in lung cancer are limited. One of the molecules participating in this pathway is the product of the c-mos proto-oncogene. In vitro investigations, in somatic cells, have shown that c-mos expression has opposing effects on cell cycle progression suggesting that it may represent an important determinant of aberrant cell function. In this study we analysed, by immunohistochemical means, its status in a series of lung carcinomas and correlated the findings with clinicopathological parameters and survival of the patients.

METHODS AND RESULTS

Sixty cases of lung carcinomas were included in the study. These comprised 52 non-small (NSCLCs) and eight small cell lung carcinomas (SCLCs). Sections from the carcinomas were immunostained with the polyclonal anti-c-mos antibody P-19. Specificity was tested by using the appropriate control peptide and control cell lines. Expression was observed in 63% of the cases, with NSCLCs showing higher reactivity (67%) than SCLCs (37.5%). Staining was observed mainly to the cytoplasm and membranes of the cancerous cells, but some nuclei reacted as well. An intratumour heterogeneous immunoreactivity was noticed. The most interesting and unexpected finding was that c-mos positive staining was associated with better recurrence-free survival in our series, regardless of histological type (P = 0.035). Furthermore, favourable disease-related and recurrence-free survival was observed in the SqC group with c-mos immunoreactivity (P < 0. 001).

CONCLUSIONS

c-mos proto-oncogene is expressed in a significant proportion of lung carcinomas and may play a role in its development. The fact that its expression is associated with a relatively good prognosis may be indicative of a negative impact on tumour growth.

Morph-specific proteins in pollen and styles of distylous turnera (Turneraceae)

We used nondenaturing isoelectric focusing (IEF) in a survey of plants from 11 populations to identify style and pollen proteins unique to the short-styled morph of Turnera scabra, T. sulnitata and T. krapovickasii. Three protein bands [approximately isoelectric points (pls) 6.1, 6.3 and 6.5] were found only in styles and stigmas of short-styled plants while two bands (approximately pls 6.7 and 6.8, M(r) 56 and 59 kD) occur only in pollen of short-styled plants. Some of these bands appear very late in development, within 24 hr before flowering. Two isozyme loci were mapped to an 8.7 cM region spanning the distyly locus. Using these isozyme markers we identified progeny exhibiting recombination adjacent to the distyly locus. No recombinants between the distyly locus and the locus or loci controlling the presence of the short-styled morph-specific proteins were obtained. This suggest that the loci encoding these proteins are either extremely tightly linked to the distyly locus and in complete disequilibrium with the S allele or exhibit morph-limited expression. Crosses to a plant showing an unusual style protein phenotype demonstrated that an additional unlinked locus is required for full expression of the style proteins. The function of the morph-specific proteins is unknown.