Classification des leucémies aiguës par les marqueurs de surface et corrélation avec le diagnostic morphologique résultats sur 111 cas

111 patients with acute leukemia, including 29 children, were classified according to the surface markers and cytochemistry of their blasts. The acute leukemias were separated into two majors groups (lymphoid and non-lymphoid) depending on the presence or absence of specific lymphoid markers. On the basis of these criteria a correlation of 94% with the hematological diagnosis was obtained. Acute lymphoblastic leukemia (ALL) was divisible into three sub-groups: 11 cases expressing T-cell specific markers were classified as T-ALL and 33 cases expressing the common ALL antigen (CALLA) as c-ALL. 18 of the latter expressed an additional marker, DSA (Daudi surface antigen), splitting c-ALL cases in two subgroups. Cytochemistry of the cases lacking specific surface markers (n = 67) served to diagnose 41 acute myeloid leukemia (AML) cases and 8 monoblastic leukemias. The remaining 18 cases could not be classified. The presence of absence of HLD-DR (Ia) antigens served to subdivide AML into two major subgroups. The prognostic significance of these new diagnostic splits is under active study.

Alteration of amino acid metabolism in neuronal aggregate cultures exposed to hypoglycaemic conditions.

The neuronal effects of glucose deficiency on amino acid metabolism was studied on three-dimensional cultures of rat telencephalon neurones. Transient (6 h) exposure of differentiated cultures to low glucose (0.25 mm instead of 25 mm) caused irreversible damage, as judged by the marked decrease in the activities of two neurone-specific enzymes and lactate dehydrogenase, 1 week after the hypoglycemic insult. Quantification of amino acids and ammonia in the culture media supernatants indicated increased amino acid utilization and ammonia production during glucose-deficiency. Measurement of intracellular amino acids showed decreased levels of alanine, glutamine, glutamate and GABA, while aspartate was increased. Added lactate (11 mm) during glucose deficiency largely prevented the changes in amino acid metabolism and ammonia production, and attenuated irreversible damage. Higher media levels of glutamine (4 mm instead of 0.25 mm) during glucose deprivation prevented the decrease of intracellular glutamate and GABA, while it further increased intracellular aspartate, ammonia production and neuronal damage. Both lactate and glutamine were readily oxidized in these neuronal cultures. The present results suggest that in neurones, glucose deficiency enhances amino acid deamination at the expense of transamination reactions. This results in increased ammonia production and neuronal damage.

Immunity to pneumococcal surface proteins in children with community-acquired pneumonia: a distinct pattern of responses to pneumococcal choline-binding protein A.

Clin Microbiol Infect ABSTRACT: The aetiological diagnosis of community-acquired pneumonia (CAP) is challenging in children, and serological markers would be useful surrogates for epidemiological studies of pneumococcal CAP. We compared the use of anti-pneumolysin (Ply) antibody alone or with four additional pneumococcal surface proteins (PSPs) (pneumococcal histidine triad D (PhtD), pneumococcal histidine triad E (PhtE), LytB, and pneumococcal choline-binding protein A (PcpA)) as serological probes in children hospitalized with CAP. Recent pneumococcal exposure (positive blood culture for Streptococcus pneumoniae, Ply(+) blood PCR finding, and PSP seroresponse) was predefined as supporting the diagnosis of presumed pneumococcal CAP (P-CAP). Twenty-three of 75 (31%) children with CAP (mean age 33.7 months) had a Ply(+) PCR finding and/or a ≥2-fold increase of antibodies. Adding seroresponses to four PSPs identified 12 additional patients (35/75, 45%), increasing the sensitivity of the diagnosis of P-CAP from 0.44 (Ply alone) to 0.94. Convalescent anti-Ply and anti-PhtD antibody titres were significantly higher in P-CAP than in non P-CAP patients (446 vs. 169 ELISA Units (EU)/mL, p 0.031, and 189 vs. 66 EU/mL, p 0.044), confirming recent exposure. Acute anti-PcpA titres were three-fold lower (71 vs. 286 EU/mL, p <0.001) in P-CAP children. Regression analyses confirmed a low level of acute PcpA antibodies as the only independent predictor (p 0.002) of P-CAP. Novel PSPs facilitate the demonstration of recent pneumococcal exposure in CAP children. Low anti-PcpA antibody titres at admission distinguished children with P-CAP from those with CAP with a non-pneumococcal origin.

Alternative reproductive strategies in Formica lugubris Zett (Hymenoptera, Formicidae)

A long term study on the reproductive strategies of Formica lugubris (Formica rufa group) has revealed many new important facts. Within a supercolony the sex-ratio is strongly female biased. Some of the sexuals mate on the nest surface, whereas others fly from the nest. Those sexuals participating in flights aggregate in particular meadow sites (mating places). On these places females attract males by releasing a sex pheromone.

Leishmania major: differential regulation of the surface metalloprotease in amastigote and promastigote stages.

During its life cycle, the protozoan parasite Leishmania major alternates from an intracellular amastigote form in the mammalian host to a flagellated promastigote form in the insect vector. The expression of the surface metalloprotease (PSP) during differentiation in vitro was investigated by Western and Northern blots, by immunoprecipitation of cells metabolically labeled with [35S]methionine or labeled at the surface with radioactive iodine, and by quantification of the proteolytic activity in substrate-containing polyacrylamide gels. We report that the surface metalloprotease is down-regulated at both the mRNA and the protein level in amastigotes, where it represents less than 1% of the equivalent proteolytic activity detected in promastigotes. A significant amount of mRNA is detected 4 hr after the onset of differentiation. The expression of the protease begins at that time and reaches steady state 8 hr later. The synthesis of PSP precedes the complete morphological differentiation to the promastigote stage and the appearance of the lipophosphoglycan, another major promastigote surface component. In contrast to PSP, a family of mercaptoethanol-activated proteases present in the amastigote exists only at a reduced level in the promastigote. The confinement of the surface metalloprotease to the insect stage of the parasite suggests that it has no physiological function in the parasitism maintenance of mammalian host macrophages.

Carboxyl terminus structural requirements for glycosyl-phosphatidylinositol anchor addition to cell surface proteins.

Glycosyl phosphatidylinositol (GPI)-anchored proteins contain in their COOH-terminal region a peptide segment that is thought to direct glycolipid addition. This signal has been shown to require a pair of small amino acids positioned 10-12 residues upstream of an hydrophobic C-terminal domain. We analysed the contribution of the region separating the anchor acceptor site and the C-terminal hydrophobic segment by introducing amino acid deletions and substitutions in the spacer element of the GPI-anchored Thy-1 glycoprotein. Deletions of 7 amino acids in this region, as well as the introduction of 2 charged residues, prevented the glycolipid addition to Thy-1, suggesting that the length and the primary sequence of the spacer domain are important determinants in the signal directing GPI anchor transfer onto a newly synthesized polypeptide. Furthermore, we tested these rules by creating a truncated form of the normally transmembranous Herpes simplex virus I glycoprotein D (gDI) and demonstrating that when its C-terminal region displays all the features of a GPI-anchored protein, it is able to direct glycolipid addition onto another cell surface molecule.

Analysis of micro- and nano-structures of the corneal surface of Drosophila and its mutants by atomic force microscopy and optical diffraction.

Drosophila melanogaster is a model organism instrumental for numerous biological studies. The compound eye of this insect consists of some eight hundred individual ommatidia or facets, ca. 15 µm in cross-section. Each ommatidium contains eighteen cells including four cone cells secreting the lens material (cornea). High-resolution imaging of the cornea of different insects has demonstrated that each lens is covered by the nipple arrays--small outgrowths of ca. 200 nm in diameter. Here we for the first time utilize atomic force microscopy (AFM) to investigate nipple arrays of the Drosophila lens, achieving an unprecedented visualization of the architecture of these nanostructures. We find by Fourier analysis that the nipple arrays of Drosophila are disordered, and that the seemingly ordered appearance is a consequence of dense packing of the nipples. In contrast, Fourier analysis confirms the visibly ordered nature of the eye microstructures--the individual lenses. This is different in the frizzled mutants of Drosophila, where both Fourier analysis and optical imaging detect disorder in lens packing. AFM reveals intercalations of the lens material between individual lenses in frizzled mutants, providing explanation for this disorder. In contrast, nanostructures of the mutant lens show the same organization as in wild-type flies. Thus, frizzled mutants display abnormal organization of the corneal micro-, but not nano-structures. At the same time, nipples of the mutant flies are shorter than those of the wild-type. We also analyze corneal surface of glossy-appearing eyes overexpressing Wingless--the lipoprotein ligand of Frizzled receptors, and find the catastrophic aberration in nipple arrays, providing experimental evidence in favor of the major anti-reflective function of these insect eye nanostructures. The combination of the easily tractable genetic model organism and robust AFM analysis represents a novel methodology to analyze development and architecture of these surface formations.

Clinical relevance of CD44 cell-surface expression and N-myc gene amplification in a multicentric analysis of 121 pediatric neuroblastomas.

PURPOSE: In contrast to other human tumors, a repression of the cell-surface glycoprotein CD44 on neuroblastoma is a marker of aggressiveness that usually correlates to N-myc amplification. We thus compared the prognostic value of both markers in the initial staging of 121 children treated for neuroblastoma in collaborative institutions. METHODS: Frozen samples were analyzed by a rapid and well-standardized technique of immunostaining with monoclonal antibodies (MoAbs) against epitopes in the CD44 constant region. RESULTS: In this retrospective series, CD44 was expressed on 102 specimens and strongly correlated with favorable tumor stages and histology, younger age, and normal N-myc copy numbers. In univariate analysis, CD44 expression and normal N-myc were the most powerful markers of favorable clinical outcome (P < 10(-6) and chi 2 = 65.40 and P < 10(-6) and chi 2 = 42.56, respectively), but analysis of CD44 affords significant prognostic discrimination in subgroups of patients with or without N-myc-amplified tumors. In the subgroup of stage IV neuroblastomas, CD44 was the only significant prognostic marker (P < .02, chi 2 = 5.76), whereas N-myc status was not discriminant. In multivariate analysis of five factors, ie, N-myc amplification, CD44 expression, age, tumor stage, and histology, the only independent prognostic factors of event-free survival were CD44 expression and tumor stage. CONCLUSION: The analysis of CD44 cell-surface expression must be recommended as an additional biologic marker in the initial staging of the disease.

Serum-free aggregate cultures of rat CNS glial cells: biochemical, immunocytochemical and morphological characterization.

Aggregate cultures of mixed glial cells, as well as of enriched astrocytes and oligodendrocytes were prepared, and maintained in serum-free medium for up to 25 days. Biochemical measurements of both neuron-specific and glia-specific enzyme activities showed that these three types of aggregate cultures were virtually devoid of neurons. Astrocyte-enriched cultures were greater than 95% pure, with oligodendrocytes as the only apparent contaminant, whereas oligodendrocyte-enriched cultures still contained a considerable proportion of astrocytes. In all these neuron-free aggregate cultures both astrocytes and oligodendrocytes attained a high degree of maturation. These findings were confirmed by morphological examinations, and by immunofluorescence studies. Furthermore, ultrastructural as well as immunocytochemical investigations using antibodies to myelin basic protein revealed that all three types of glial cell aggregate cultures contained myelin membranes, indicating that the presence of axons is not a prerequisite for the formation of myelin.

Surface granularity as a discriminating feature of illicit tablets

In this paper we propose an innovative methodology for automated profiling of illicit tablets bytheir surface granularity; a feature previously unexamined for this purpose. We make use of the tinyinconsistencies at the tablet surface, referred to as speckles, to generate a quantitative granularity profileof tablets. Euclidian distance is used as a measurement of (dis)similarity between granularity profiles.The frequency of observed distances is then modelled by kernel density estimation in order to generalizethe observations and to calculate likelihood ratios (LRs). The resulting LRs are used to evaluate thepotential of granularity profiles to differentiate between same-batch and different-batches tablets.Furthermore, we use the LRs as a similarity metric to refine database queries. We are able to derivereliable LRs within a scope that represent the true evidential value of the granularity feature. Thesemetrics are used to refine candidate hit-lists form a database containing physical features of illicittablets. We observe improved or identical ranking of candidate tablets in 87.5% of cases when granularityis considered.

Tuning the immune response of dendritic cells to surface-assembled poly(I:C) on microspheres through synergistic interactions between phagocytic and TLR3 signaling.

The artificial dsRNA polyriboinosinic acid-polyribocytidylic acid, poly(I:C), is a potent adjuvant candidate for vaccination, as it strongly drives cell-mediated immunity. However, because of its effects on non-immune bystander cells, poly(I:C) administration may bear danger for the development of autoimmune diseases. Thus poly(I:C) should be applied in the lowest dose possible. We investigated microspheres carrying surface-assembled poly(I:C) as a two-in-one adjuvant formulation to stimulate maturation of monocyte-derived dendritic cells (MoDCs). Negatively charged polystyrene microspheres were equipped with a poly(ethylene glycol) corona through electrostatically driven surface assembly of a library of polycationic poly(l-lysine)-graft-poly(ethylene glycol) copolymers, PLL-g-PEG. Stable surface assembly of poly(I:C) was achieved by incubation of polymer-coated microspheres in an aqueous poly(I:C) solution. Surface-assembled poly(I:C) exhibited a strongly enhanced efficacy to stimulate maturation of MoDCs by up to two orders of magnitude, as compared to free poly(I:C). Multiple phagocytosis events were the key factor to enhance the efficacy. The cytokine secretion pattern of MoDCs after exposure to surface-assembled poly(I:C) differed from that of free poly(I:C), while their ability to stimulate T cell proliferation was similar. Overall, phagocytic signaling plays an important role in defining the resulting immune response to such two-in-one adjuvant formulations.