Distinct population of hair cell progenitors can be isolated from the postnatal mouse cochlea using side population analysis.

In mammals, the permanence of hearing loss is due mostly to the incapacity of the cochlea to replace lost mechano-receptor cells (i.e., hair cells [HCs]). The generation of new HCs from a renewable source of progenitors is a principal requirement for developing a cell therapy within this sensory organ. A subset of stem cells, termed side population (SP), has been identified in several tissues of mammals. The ATP-binding cassette transporter Abcg2/Bcrp1 contributes to the specification of the SP phenotype and is proposed as a universal marker for stem/progenitor cells. A defining character of these SP cells is a high efflux capacity for Hoechst dye. Here, we demonstrate that Abcg2 transporter is expressed with two other stem/progenitor cell markers (i.e., Nestin and Musashi1) in distinct and overlapping domains of the supporting cells within the postnatal cochlea. We have developed and describe a fluorescence-activated cell sorting (FACS) technique that enables the purification of a discrete subpopulation of SP-supporting cells from the early postnatal mouse cochlea based on their ability to exclude Hoechst dye. These FACS-isolated cells can divide and express markers of stem/progenitor cells such as Abcg2, a determinant of the SP phenotype, and Musashi1, a neural stem/progenitor cell marker. These markers can differentiate cells expressing markers of HCs and supporting cells in vitro. Our observation that these SP cells are capable of differentiating into HC-like cells implies a possible use for such cells (i.e., the replacement of lost auditory HCs within damaged cochlea).     

Delay and not deficiency in cap formation of peripheral blood B cells in patients with multiple myeloma

A major problem in the study of peripheral blood (PB) B cells from patients with multiple myeloma (MM) is the distinction between the cells really able to synthesize membrane (m) immunoglobulins (Ig) and those able only to absorb serum Ig passively, since the lymphocytes of such patients are bathed in very high concentrations of monoclonal Ig. In order to reappraise PB B cells (including putative pre-B cells) in MM, we have used three different criteria: (a) the capacity of PB B cells to cap mIg when triggered by an anti-Ig; (b) the presence of B-cell differentiation antigens (CD19, CD20, CD21, and CD37) as specific B-cell markers; and (c) the expression of cytoplasmic heavy chain as a marker of pre-B cells. We have found that, in active myeloma (N=13), the percentages and absolute numbers of PB B cells able to cap mIg (4.25%; 45.43 cells/mm³) were significantly lower than those in healthy donors (8.4%; 151.2 cells/mm³) and those in stable MM (7.67%; 134.39 cells/mm³). In addition, the capping formation in patients with stable or active MM was significantly delayed compared to that in healthy donors. For all the normal individuals and patients investigated, there has been found an excellent correlation between the percentages and absolute numbers of PB B cells able to cap their mIg and those of PB mononuclear cells bearing the four B cell-specific differentiation antigens: CD19, CD20, CD21, and CD37. Finally, virtually no pre-B cells bearing cytoplasmic chains have been identified in the peripheral blood from healthy donors and patients with MM.     

Mondor's disease. A radioclinical diagnosis, concerning one case (author's transl)]

The authors present a typical case of Mondor's disease of the superior external quadrant of the breast. They discuss two specific points: --the absence of superior-internal venous drainage; --the radiological picture given by a thrombosed vein.     

Oxidation and biotinylation of beta 2 glycoprotein I glycan chains induce an increase in its affinity for anionic phospholipids similar to that obtained by the addition of anti-beta 2 glycoprotein I or anti-cardiolipin antibodies

Binding of beta 2 glycoprotein I (β₂GPI) to apoptotic cells plays a key role in the opsonization of apoptotic bodies and the formation of antiphospholipids antibodies. Here, we describe the binding of β₂GPI to apoptotic cells using β₂GPI labelled with biotin-hydrazide (β₂GPI-bh) after oxidation of its glycan chains. Flow cytometry analyses and confocal microscopy showed that β₂GPI-bh, contrary to native β₂GPI, bound to apoptotic cells, either permeable or non-permeable to propidium iodide (PI), as did annexin-V–FITC. But, in the absence of divalent ions, β₂GPI-bh, contrary to annexin V, was still able to bind to apoptotic cells. Binding equilibrium studies, performed on solid-state anionic phospholipids (AnPL), revealed that β₂GPI-bh had a greater apparent affinity for AnPL than native β₂GPI. In presence of the anti-β₂GPI mAb 8C3, the ability of native β₂GPI to bind to AnPL was increased and binding to apoptotic PI⁺ and PI⁻ CEM cells was observed whereas binding of β₂GPI-bh was barely affected by the addition of 8C3. However, the 8C3-enhanced ability of native β₂GPI to bind to AnPL was still weaker than that of β₂GPI-bh. It is not clear why the oxidation and biotinylation of glycan chains of β₂GPI increases its affinity for AnPL, but it seems that if such oxidative process occurs naturally, it could participate in enhancing antiphospholipid formation.     

CD5 B lymphocyte antigen in monoclonal gammopathy.

Because B lymphocytes bearing the CD5 antigen have been involved in many B-cell malignancies, we have investigated the presence of the CD5 B-cell antigen on B and plasma cells in monoclonal gammopathy. Quantification of CD5 B cells was made in the peripheral blood of seven individuals with monoclonal gammopathy of undetermined significance (MGUS) and in that of 21 patients with multiple myeloma (MM). The bone marrow of ten patients with MM was also studied. Patients with progressive MM presented a significant reduction in both B and CD5 B lymphocytes (i.e., percentages and absolute numbers), when compared with individuals with MGUS and patients with stable MM. These latter individuals and patients did not differ from healthy donors. No CD5 B cells were found in the bone marrow of patients with MM. Moreover, no CD5 antigen could be detected on eight freshly established human myeloma cells lines including six totally dependent on interleukin-6. However, it was weakly expressed on two standard myeloma cell lines not requiring exogenous interleukin-6 (i.e., RPMI 8226 and U 266). In conclusion, our data show mainly an overall reduction of the polyclonal CD5 B lymphocytes similar to what is observed for the other polyclonal B lymphocytes in patients with active MM. Finally, the expression of the CD5 antigen human myeloma cell lines is not constant.     

Dairy products, calcium and the risk of breast cancer: results of the French SU.VI.MAX prospective study

The aim was to estimate the association between dairy products (total and their subgroups), calcium intake and the risk of breast cancer. As few studies have considered menopausal status, we also investigated stratified analyses. This analysis included 3,627 women from the French SU.VI.MAX study, among whom 92 developed breast cancer during the follow-up period. Food consumption was assessed based on five 24-hour records completed during the previous 18 months to follow-up. Calcium intake was calculated using an ad-hoc food composition database. Cox proportional hazards models were used to estimate relative risk (RR), comparing 4th quartile vs. 1st quartile, and 95% confidence intervals (95% CI). A lower risk of breast cancer was observed with high total dairy product consumption in the whole population (RR = 0.55, 95% CI = 0.29-1.03, p(trend) = 0.03) and among premenopausal women with a RR of 0.35 (95% CI = 0.12-0.95, p(trend) = 0.01). None of these associations remained after control for calcium intake. Increasing calcium intake was inversely associated with breast cancer risk considering the whole population (RR = 0.50, 95% CI = 0.27-0.91, p(trend) = 0.04) and among the subgroup of premenopausal women (RR = 0.26, 95% CI = 0.10-0.71, p(trend) = 0.01) respectively. Our data support the hypothesis that dairy products, through calcium content or a correlated component, might have a negative association with the risk of breast cancer, particularly among premenopausal women.