Hélène Kiefer

HUMAN CHROMOSOME MICRODISSECTION AND FLUORESCENCE ANALYSIS BY LASER SCANNING IMAGE CYTOMETRY

Mesentericin YI05 (mYI05) a bacteriocin secreted by Leuconostoc mesenteroides ssp mesenteroides YI05. kills only Listeria types. The bactericidal effect estimates by microbiological methods using well diffusion tests may be observed after an incubation of at least 16 hours. To reduce the analytical delay, we have routinely used fluorescent potential dyes and flow cytometry to determine the bactericidal effect. Because structural parameters (i.e. Forward Angle Scatter, DNA content...) are slowly altered under mY I05 effect, we have preferentially followed the modification of functional parameters such as membrane potential. Decrease of bacteria fluorescence due to release of potential sensitive dye (Rhodamine 123 or DiOC6(3)) is rapidly and significantly observed in less than I rain after bacteriocin incorporation in the incubation medium. This result agrees well with biochemical studies (Maftah et al., 1993, J. Bacteriol. 175, 3232-3235) which assume that mY l05 induces the permeabilization of Listeria plasmic membrane. Potential alterations vary with Listeria species, and for resistant strains potential is slightly modified. Otherwise, analysis carried out with protoplasts of sensitive and resistant Listeria strains, could suggest that one or some components of bacterial wall are thightly implicated in the recognition of mYl05.

PURIFICATION OF MOUSE CHROMOSOMES BY FLOW‐CYTOMETRY: CONSTRUCTION AND CHARACTERIZATION OF A GENOMIC LIBRARY FROM CHROMOSOME 19

The d i f f e r e n ~ i a l d iagnos is o f t h y z o i d neoplasms ~hich can appear as quite difficult by routine =ytology prompted many authors to measure the nucleus DNA unsuccesfully (1,2). We therefore have though~ that image analysis could produce fureher information in orde~ to exclude the benign lesions. Seventy six patients whose thyroid cold nodule ~as surgically excised after fine needle asplraClon blopsy and examined by pathologlsC entered the s~udy (le : 56 ben~gn, -18 mallgnanC and 2 aeyplcal adenoma). A sac of 3662 cells from 33 benign cases was compared to another set of 1712 cells from 11 mallgnan~ nodules. The dlscrlmlnaEion begw~en the two populations was based on 4 nuclear features. From these da~8 the rate of nuclei which could be regarded as benign was computed for each case. The average ra~e fo r the 33 benign cases was 85%, In a p r o s p e c t i v e s~udy b e a r i n g on che 32 remaining patients, sensiClvlCy and specificity o f conven t i ona l cy to logy (CC) were r e s p e c ~ i v i l y 69% and 71% ver sus 92 and 88% f o r quancicaC~ve cy to l ogy (QC), However, l o g i s t i c regress ion a n a l y s i s l n d i c a ~ e d tha~ CC (wi~h p • .0027) had a complementary r o l e to. ~ha~ of QC (p • .0002) In the d i a g n o s i s of ~hyrold neoplams. So f a r we have to c o n s i d e r both t he me~hods as complementary to each ocher .

Ultrastructural and Y-PCR analysis of trophoblast-like cells detected in peripheral maternal blood using antibodies and flow cytometry sorting

The d i f f e r e n ~ i a l d iagnos is o f t h y z o i d neoplasms ~hich can appear as quite difficult by routine =ytology prompted many authors to measure the nucleus DNA unsuccesfully (1,2). We therefore have though~ that image analysis could produce fureher information in orde~ to exclude the benign lesions. Seventy six patients whose thyroid cold nodule ~as surgically excised after fine needle asplraClon blopsy and examined by pathologlsC entered the s~udy (le : 56 ben~gn, -18 mallgnanC and 2 aeyplcal adenoma). A sac of 3662 cells from 33 benign cases was compared to another set of 1712 cells from 11 mallgnan~ nodules. The dlscrlmlnaEion begw~en the two populations was based on 4 nuclear features. From these da~8 the rate of nuclei which could be regarded as benign was computed for each case. The average ra~e fo r the 33 benign cases was 85%, In a p r o s p e c t i v e s~udy b e a r i n g on che 32 remaining patients, sensiClvlCy and specificity o f conven t i ona l cy to logy (CC) were r e s p e c ~ i v i l y 69% and 71% ver sus 92 and 88% f o r quancicaC~ve cy to l ogy (QC), However, l o g i s t i c regress ion a n a l y s i s l n d i c a ~ e d tha~ CC (wi~h p • .0027) had a complementary r o l e to. ~ha~ of QC (p • .0002) In the d i a g n o s i s of ~hyrold neoplams. So f a r we have to c o n s i d e r both t he me~hods as complementary to each ocher .

A QUANTITATIVE ANALYSIS OF MHC CLASS II MOLECULE EXPRESSION IN MURINE MACROPHAGES INFECTED WITH LEISHMANIA AMAZONENSIS

Resolution or exacerbation of lesions caused by Leishmunia (a pathogenic protozoa living within macrophages of certain mammals) results from induction of T lymphocytes responses. More specifically, subsets of CD4+ helper T lymphocytes have been shown to play a major role in the outcome of infection. The interaction of parasitic antigens with accessory cells expressing MHC-encoded class 11 molecules (l.a) -known as antigen-presenting cells (APC)is required for the stimulation of anti-Leishmania CD4+ T cells. The nature of the APC involved in these diseases remains to be determined but infected macrophages are potential candidates. To approach this question, we studied the ability of hone-mmmw-dedved macrophages from BALBIc mice to express la molecules after infection with L.amazonensis