Maternal immunoglobulins have no effect on the rate of maturation of the B cell compartment of the offspring

To elucidate a general role of maternal immunoglobulins (Ig) on the kinetics of B cell development of the offspring, we studied non-genetic influences of maternal Ig on the developing immune system of B cell-competent mice. These animals were the offsprings of either B cell-deprived μMT or of normal C57BL/6 females. In these mice, we have compared the kinetics of Ig production, the numbers of B cell progenitors, the expression of surface markers specific of the B lineage and the progression of Ig variable gene expression. We show that the absence of maternal Ig has no detectable effect on the kinetics of IgM and IgG production by the offspring's immune system. The number of B cell precursors, the kinetics of generation of B cells and their pattern of surface markers expression is identical in both types of mice. The acquisition of diversity in the B cell repertoire and the changes in the ratios of variable gene family expression are also indistinguishable. We conclude that maternally derived Ig has no influence on the rate of development and maturation of the B cell compartment of the offspring.     

Investigation of the infertile couple: when is the appropriate time to explore female infertility?

While the appropriate method for the investigation of female infertility continues to be debated, the timing of the investigation has received less attention. The current approach is time-consuming, and paradoxically may lead to overtreatment as well as undertreatment. Recent findings on fecundity and the conception window in humans have important implications for the timing of the investigation of female infertility. The findings support the view that fertility-oriented intercourse may have a major impact in reducing the time to pregnancy. Procedures for the investigation of female infertility are becoming less invasive and more accurate, while the therapies for infertility are more effective. It is proposed that under appropriate circumstances female infertility should be investigated after 6 months of fertility-oriented intercourse.     

Integrin α6 expression in human prostate carcinoma cells is associated with a migratory and invasive phenotypein vitro andin vivo

Cell adhesion and migration are important features in tumor invasion, being mediated in part by integrins (extracellular matrix receptors). Integrins are significantly decreased in human prostate cancer. An exception is 6 integrin (laminin receptor) which persists during prostate tumor progression. We have selected high (DU-H) and low (DU-L) expressors of 6 integrin from a human prostate tumor cell line, DU145, to assess experimentally the importance of 6 integrin in tumor invasion. DU-H cells exhibited a four-fold increased expression of 6 integrin on the surface compared to DU-L cells. Both cell types contained similar amounts of 3 and 5 integrin. The DU-H cells contained 6 subunits complexed with both the 1 and 4 subunits whereas DU-L cells contained 6 complexed only with 4. DU-H cells were three times more mobile on laminin as compared to DU-L, but adhered similarly on laminin. Adhesion and migration were inhibited with anti-6 antibody. Each subline was injected intraperitoneally into SCID mice to test its invasive potential. Results showed greater invasion of DU-H compared to DU-L cells, with increased expression of a6 integrin on the tumor at the areas of invasion. These data suggest that 6 integrin expression is advantageous for prostate tumor cell invasion.     

Modulation of the transcripts for tumor necrosis factor-α and its receptors in vivo

We investigated the effects of a single bacterial lipopolysaccharide (LPS) injection in vivo on the gene expression of tumor necrosis factor-α (TNF) and its receptors: TNF receptor type I (TNF-R 55 kDa or TNF-R1) and TNF receptor type II (TNF-R 75 kDa or TNF-R2) in various tissues and white blood cells. While TNF mRNA rapidly accumulated in most tissues, TNF-R1 and TNF-R2 mRNA levels were found to be differentially regulated in lung, spleen, lymph nodes and white blood cells. In most cases, TNF-R mRNA levels did not parallel TNF mRNA levels. These observations indicate that TNF-R of both types are capable of modulating the host response to LPS, not only by shedding of their extracellular domains, but also by strict regulation of their gene expression.     

Noninvasive fluorescent study in situ and in real time of glucose effects on the pharmacokinetic of calcein

This study was undertaken to compare the effect of glucose injection on the pharmacokinetic behavior of a soluble dye in normal and tumoral tissues. The measurements were done using a noninvasive fluorescent spectroscopy in situ and in real time. The experiments were performed on three groups of animals with calcein as a soluble pH-insensitive fluorescent dye combined or not with glucose. Glucose solution was injected 5 or 30 min before calcein. Fluorescence emission intensity was recorded on normal and tumor tissues with an optical multichannel analyzer. Calcein concentration was also measured in blood using repetitive blood sampling. In the control group (without glucose injection), calcein is rapidly cleared from the blood, with a slow tissue clearance. Fluorescence of normal tissue was higher than fluorescence measured in tumor tissue. When glucose is injected 5 min before calcein, there was a rapid increase of tissue fluorescence followed by a plateau remaining during the whole experiment. No difference between tumor and normal tissue fluorescence intensity was observed. When glucose was injected 30 min before calcein, the plateau phase was reduced to 50 min in normal tissue. Tumor tissue fluorescence displays no distinct plateau phase. These results clearly showed the effect of glucose injection in situ and in real time, by a noninvasive method, on the pharmacokinetic of a soluble dye in a tumor tissue compared to a normal tissue. Differences between blood compartment and tissues kinetic profiles were also clearly demonstrated.     

Cloning,sequencing and analysis of the yeastS. uvarum ERG10 gene encoding acetoacetyl CoA thiolase

Summary TheERG10 gene specific toS. uvarum, a brewing yeast, has been cloned by complementation of anS. cerevisiae erg10 mutant.S. uvarum contains two differentERG10 genes. One of these is similar to theS. cerevisiae ERG10 gene; they are structurally different, but functionally homologous. The clonedERG10 gene has been located on chromosome XVI, and we have shown that it is allelic to the previously isolatedtsm0115 mutants. Northern blot and sequence analysis indicate that theERG10 gene is highly expressed, and biochemical and genetic evidence show that it encodes the cytoplasmic acetoacetyl CoA thiolase.     

Trypanosoma cruzi: Killing and enhanced uptake by resident peritoneal macrophages treated with alpha-2-macroglobulin

We report that alpha-2-macroglobulin (A2M), the physiologically important plasma protease inhibitor and suspected immunomodulator, alters the functional ability of murine resident peritoneal macrophages (RM) to ingest and kill the infective trypomastigote stage ofTrypanosoma cruzi, the aetiological agent of Chagas' disease. Treatment of RM with 500 g/ml A2M for 30 min enhanced the uptake of trypomastigotes, epimastigotes, and amastigotes by 125%, 46%, and 300%, respectively. The same treatment also increased the phagocytosis of sheep erythrocytes opsonized with complement and IgG as well as of galactosylated asialoerythrocytes. After 60–90 min parasite-cell interaction, epi-and amastigotes were killed by the RM, whereas the infection with trypomastigotes was controlled only after 24 h. Other protease inhibitors, bovine serum albumin, and LPS showed no such effect. The production of hydrogen peroxide was not affected by A2M treatment, but the ultrastructural aspects showed trypomastigote damage and enhancement of macrophage membrane ruffling, indicative of macrophage activation. These results suggest that A2M has the ability to modulate, at least functionally, certain receptor-mediated endocytic pathways that, in concert with an activation of possibly oxygen-independent microbicidal mechanisms, could contribute to resistance against the parasite.Abbreviations A2M alpha-2-macroglobulin - F-A2M fast A2M - S-A2M slow A2M - RM resident macrophages - BT bloodstream trypomastigotes - EPI epimastigotes - AMA amastigotes - DMEM Dulbecco's Modified Eagle Medium - PBS phosphate-buffered saline - BSA bovine serum albumin - LPS bacto lipopolysaccharide - STI sovoean trypsin inhibitor - PPA pepstatin A - LPT leupeptin - PNT 1, 10-phenanthroline - TLCK N--tosy-L-lysine-chloromethylketone - E sheep erythrocyte - aE asialoerythrocyte - Gal R receptors for galactosylated particles     

Use of type 1 /type 2 chimeric polioviruses to study determinants of poliovirus type 1 neurovirulence in a mouse model

We previously described the characteristics of a type 1/type 2 (PV-1/PV-2) chimeric poliovirus, v510, which contains the six amino acids specific for PV-2 in the B-C loop of VP1. This virus was found to be mouse-adapted, as PV-2 and in contrast with PV-1. Determinants of host range were studied in detail and are reported here. PV-1/PV-2 chimeras containing partial PV-1----PV-2 substitutions in the B-C loop of VP1 were obtained by making use of a mutagenesis cartridge on PV-1 cDNA. Analysis of mouse neurovirulence of these chimeras, when correlated with the three-dimensional structure of the v510 capsid, revealed that PV-2 residues important for mouse tropism are those which determine the particular conformation of the B-C loop of VP1 in v510. The mutation of the adenine residue at position 480 of the 5' noncoding region into a guanine residue has been shown to be an important determinant of PV-1 attenuation in monkeys. We show that introduction of this mutation in the v510 genome results in a virus which is partially attenuated for mice. This suggests that analysis of genomic determinants important for PV-1 neurovirulence could be carried out in a mouse model by making use of a mouse-adapted PV-1/PV-2 chimera.