[A KEL*02mod allele responsible for an apparent maternity exclusion]

The patient's rare KEL:1,-2 phenotype was highlighted in course of a routine preoperative erythrocyte typing. Unexpectedly, her two daughters presented a KEL:-1,2 phenotype what appeared first as an apparent maternity exclusion. Flow cytometry, genotyping and adsorption-elution analyses were then performed for those three patients. KEL genotyping showed that the patient's genotype was KEL*01/KEL*02 whereas that of her daughters was KEL*02/KEL*02. By using polyclonal anti-KEL2 reagent, weak amount of KEL2 was identified on the patient's erythrocytes, a result which was confirmed by both flow cytometry and adsorption-elution assays, suggesting that patient's phenotype was in fact KEL:1,2w. These results are in favour of a weak expressed KEL*02 allele (KEL*2mod) transmission coding for a KEL2 antigen detected in some technical conditions only. Those results allowed to explain the apparent maternity exclusion based on initial KEL phenotype. This study also seems to confirm the presence of a compensatory mechanism of the KELmod allele deficient expression in heterozygote patients. A KEL phenotype retrospective study of 80,000 subjects showed a local KEL:1,-2 frequency four times lower than that described in literature. Moreover, a significant number of those individuals would in reality be KEL:1,2w, what still would decrease the real frequency of the KEL:1,2 subjects.

A completely automated CAD system for mass detection in a large mammographic database

Mass localization plays a crucial role in computer-aided detection (CAD) systems for the classification of suspicious regions in mammograms. In this article we present a completely automated classification system for the detection of masses in digitized mammographic images. The tool system we discuss consists in three processing levels: (a) Image segmentation for the localization of regions of interest (ROIs). This step relies on an iterative dynamical threshold algorithm able to select iso-intensity closed contours around gray level maxima of the mammogram. (b) ROI characterization by means of textural features computed from the gray tone spatial dependence matrix (GTSDM), containing second-order spatial statistics information on the pixel gray level intensity. As the images under study were recorded in different centers and with different machine settings, eight GTSDM features were selected so as to be invariant under monotonic transformation. In this way, the images do not need to be normalized, as the adopted features depend on the texture only, rather than on the gray tone levels, too. (c) ROI classification by means of a neural network, with supervision provided by the radiologist's diagnosis. The CAD system was evaluated on a large database of 3369 mammographic images [2307 negative, 1062 pathological (or positive), containing at least one confirmed mass, as diagnosed by an expert radiologist]. To assess the performance of the system, receiver operating characteristic (ROC) and free-response ROC analysis were employed. The area under the ROC curve was found to be Az = 0.783 +/- 0.008 for the ROI-based classification. When evaluating the accuracy of the CAD against the radiologist-drawn boundaries, 4.23 false positives per image are found at 80% of mass sensitivity.

Subcellular localization and in vivo identification of the putative movement protein of olive latent virus 2

The gene encoding the 36.5 kDa ('36K') nonstructural protein located on RNA3 of olive latent virus 2 (OLV-2) was cloned, expressed with the Escherichia coli pGEX-2T system and the purified protein used to raise a polyclonal antiserum. Immunoblot analysis of OLV-2-infected Nicotiana benthamiana plants showed that the 36K protein accumulated in the early stages of infection and was associated with a subcellular fraction enriched in cytoplasmic membranes. In infected cells there were tubular structures, some containing virus-like particles, scattered in the cytoplasm or protruding from or penetrating the cell wall at the plasmodesmata. Immunogold labelling localized the 36K protein in the plasmodesmata of OLV-2-infected cells and showed it to be associated with virus-containing tubules. Leaf trichome cells of N. tabacum plants, transformed with a 36K-green fluorescent protein (GFP) fusion construct, revealed localized fluorescence in the cell walls, possibly due to association of the fusion protein with plasmodesmata. When the same 36K-GFP fusion protein was expressed in N. tabacum protoplasts, long tubular fluorescent structures protruded from the protoplast surface, suggesting that the 36K protein is responsible for tubule induction. The conclusion is drawn that this protein is likely to be the OLV-2 movement protein, mediating cell-to-cell virus movement, and that movement is by a tubule-guided mechanism.

Prevalence of hepatitis G virus in a haemodialysis unit

BACKGROUND

Recently, a novel blood-borne virus has been identified and named hepatitis G virus. Transfusion is the main route of transmission. It is known that patients on maintenance dialysis are more susceptible to infections with parenterally-transmitted viruses than the general population. The aim of the present study was to determine the prevalence of hepatitis G infection in a Belgian dialysis unit.

METHODS

The entire population of our dialysis unit (82 patients) was tested for the presence of hepatitis G virus (HGV) by reverse transcriptase polymerase chain reaction. History of transfusion or renal transplantation, coinfections with hepatitis B and C viruses, and serum aminotransferase levels were also tested.

RESULTS

Thirteen patients (16%) were found positive for HGV-RNA. Among these patients, 69.2% were infected by the G virus alone, 15.4% were coinfected with B virus, and 15.4% with C virus. All but one patient had a history of transfusion. Ten of the thirteen infected patients (77%) had normal aminotransferase (< 30 UI/l). Three patients had elevated aminotransferase levels (23%); one was coinfected with B virus, one with C virus, and the last one had a diabetes-induced fatty liver infiltration. No liver biopsies were performed.

CONCLUSIONS

It is concluded that infection with G virus is common among dialyzed patients. This high rate of infection could be related to previous transfusions, but may as well be due to nosocomial transmission. In our series, at least one patient has been contaminated by another road than transplantation or transfusion. Finally, it does not appear clearly that chronic infection with hepatitis G virus induces liver disease, as defined by elevated aminotransferase level.

[Determination of anti-tetanus antibodies using protein A labeled with iodine 125]

We present a quantitative measurement of specific antitetanic IgG immunoglobulins with protein "A" labeled with I125. The Laurell's immunoelectrophoresis was the reference method. After having fixed optimum conditions of duration and temperature of de reaction, we studied the different concentrations of the coated antigen and also the different dilution of serum. We can so eliminate the most aspecific effects of the antigen-antibody reaction. The correlation between the two methods of measurement is more than 98%.