Early evaluation of natural killer activity in post-transplant acute myeloid leukemia patients.

The focus of this study was to investigate NK cell reconstitution early after hematopoietic stem cell transplantation (HSCT). We were particularly interested in acute myeloid leukemia (AML) since patients with this disease may display an altered NK cell function. The function and the phenotype of donor-derived NK cells obtained from 35 allografted patients 30 and 60 days after HSCT for AML or other-than-AML hematological malignancies has been assessed. NK functional status was investigated by measuring the degranulation capacity (externalization of CD107a) of NK cells against human K562. We also concomitantly determined the concentration of selected cytokines known to modulate NK function and/or receptor expression. At day 30, donor-derived AML and non-AML NK cells could efficiently degranulate when exposed to leukemic K562 targets. At day 60, we observed a reduced NK degranulation potential in AML patients only. Decreased NK activity in AML patients was concomitant to NKp46 and NKp30 down-regulation. AML NK cells were chronically exposed to low IL-2 levels following HSCT. TGF-beta(1) was undetectable in all patients. In AML, the functional activity of donor-derived NK cells is remarkable at day 30 but may strongly decrease two months after HSCT. Therefore, in this condition, early NK immune-modulation might improve HSCT outcome.

Acute ethanol administration oxidatively damages and depletes mitochondrial dna in mouse liver, brain, heart, and skeletal muscles: protective effects of antioxidants.

Ethanol metabolism causes oxidative stress and lipid peroxidation not only in liver but also in extra-hepatic tissues. Ethanol administration has been shown to cause oxidative degradation and depletion of hepatic mitochondrial DNA (mtDNA) in rodents, but its in vivo effects on the mtDNA of extra-hepatic tissues have not been assessed. We studied the effects of an acute intragastric ethanol administration (5 g/kg) on brain, heart, skeletal muscle, and liver mtDNA in mice. Ethanol administration caused mtDNA depletion and replacement of its supercoiled form by linearized forms in all tissues examined. Maximal mtDNA depletion was about similar (ca. 50%) in all organs studied. It occurred 2 h after ethanol administration in heart, skeletal muscle, and liver but after 10 h in brain. This mtDNA depletion was followed by increased mtDNA synthesis. A secondary, transient increase in mtDNA levels occurred 24 h after ethanol administration in all organs. In hepatic or extra-hepatic tissues, mtDNA degradation and depletion were prevented by 4-methylpyrazole, an inhibitor of ethanol metabolism, and attenuated by vitamin E, melatonin, or coenzyme Q, three antioxidants. In conclusion, our study shows for the first time that ethanol metabolism also causes oxidative degradation of the mitochondrial genome in brain, heart, and skeletal muscles. These effects could contribute to the development of (cardio)myopathy and brain injury in some alcoholic patients. Antioxidants prevent these effects in mice and could be useful in persevering drinkers.

Caspase activation is required for terminal erythroid differentiation.

The cysteine proteases known as caspases play a central role in most apoptotic pathways. Here, we show that caspase inhibitors arrest the maturation of human erythroid progenitors at early stages of differentiation, before nucleus and chromatin condensation. Effector caspases such as caspase-3 are transiently activated through the mitochondrial pathway during erythroblast differentiation and cleave proteins involved in nucleus integrity (lamin B) and chromatin condensation (acinus)without inducing cell death and cleavage of GATA-1. These observations indicate a new function for caspases as key proteases in the process of erythroid differentiation.

Purification, amplification and characterization of a population of human erythroid progenitors.

In humans, studies of the erythroid cell lineage are hampered by difficulties in obtaining sufficient numbers of erythroid progenitors. In fact, these progenitors in bone marrow or peripheral blood are scarce and no specific antibodies are available. We describe a new method which allows proliferation in liquid culture of large numbers of pure normal human erythroid progenitors. CD34+ cells were cultured for 7 d in serum-free conditions with the cytokine mixture interleukin (IL)-3/IL-6/stem cell factor (SCF). This resulted in cell expansion and the appearance of a high proportion of CD36+ cells which were purified on day 7. Methylcellulose clones from these cells were composed of 96.6% late BFU-E and 3.4% CFU-GM. These CD36+ cells could be recultured with the same cytokine mixture plus or minus erythropoietin (Epo) for a further 2-7 d. In both conditions further amplification of CD36+ cells was observed, but Epo induced a more dramatic cell expansion. Glycophorin-positive mature cells appeared only in the presence of Epo, and terminal red cell differentiation was observed after 7 d of secondary culture. Cells obtained from adult CD34+ progenitors mostly contained adult haemoglobin, whereas cord blood-derived cells contained equal proportions of adult and fetal haemoglobin. Activation of STAT5 and tyrosine phosphorylation of the Epo receptor and JAK2 were observed after Epo stimulation of these cells. This new method represents a straightforward alternative to the procedures previously described for the purification of normal erythroid progenitors and is useful in the study of erythropoietic regulation.

An alcoholic binge causes massive degradation of hepatic mitochondrial DNA in mice.

BACKGROUND & AIMS: Ethanol causes oxidative stress in the hepatic mitochondria of experimental animals and mitochondrial DNA deletions in alcoholics. We postulated that ethanol intoxication may cause mitochondrial DNA strand breaks. METHODS: Effects of an intragastric dose of ethanol (5 g/kg) on hepatic mitochondrial DNA levels, structure, and synthesis were determined by slot blot hybridization, Southern blot hybridization, and in vivo [3H]thymidine incorporation, respectively. RESULTS: Two hours after ethanol administration, ethane exhalation (an index of lipid peroxidation) increased by 133%, although hepatic lipids were unchanged. Mitochondrial DNA was depleted by 51%. Its supercoiled form disappeared, whereas linearized forms increased. Long polymerase chain reaction evidenced lesions blocking polymerase progress on the mitochondrial genome. Mitochondrial transcripts decreased. Subsequently, [3H]thymidine incorporation into mitochondrial DNA increased, and mitochondrial DNA levels were restored. In contrast, nuclear DNA was not fragmented and its [3H]thymidine incorporation was unchanged. Liver ultrastructure only showed inconstant mitochondrial lesions. Ethanol-induced mitochondrial DNA depletion was prevented by 4-methylpyrazole, an inhibitor of ethanol metabolism, and attenuated by melatonin, an antioxidant. CONCLUSIONS: After an alcoholic binge, ethanol metabolism causes oxidative stress and hepatic mitochondrial DNA degradation in mice. DNA strand breaks may be involved in the development of mitochondrial DNA deletions in alcoholics.

[In vitro detection of prostate cancer circulating cells by immunocytochemistry, flow cytometry and RT-PCR PSA]. / Détection in vitro des cellules circulantes dans le cancer de la prostate par immunocytochimie, cytométrie en flux et RT-PCR PSA.

OBJECTIVE: To evaluate 3 in vitro methods detection (immunocytochemistry, flow cytometry and RT-PCR PSA) of circulating prostate cancer cells from a model of uncap dilution in immortalised lymphocytes. METHODS: In vitro comparison of 3 techniques (immunocytochemistry, flow cytometry, RT-PCR PSA) was performed from a range of dilutions of LbCap cells in immortalised human lymphocytes (concentration range: 1 LnCap cell per 100 lymphocytes to 1 LnCap cell per 100 million lymphocytes). Cells were detected by anti-PSA (prostate specific antigen) and PAP (prostatic acid phosphatase) antibody by immunochemistry, by fluorescent linked antipancytokeratin antibody by flow cytometry and RT-PCR PSA. RESULTS: The limit of detection was 1 LnCap cell per 200,000 lymphocytes (1/2.10(5)) for immunochemistry, 1 LnCap cell per 1,000 lymphocytes (1/1.10(3)) for flow cytometry and 1 LnCap cell per 10 million lymphocytes (1/10(7)) for RT-PCR PSA. CONCLUSION: RT-PCR, due to its most perceptible limit of detection, appears to be the method of choice for the detection of prostatic epithelial cells. Immunocytochemistry has the advantage of providing a quantitative approach. Flow cytometry is limited by the limit of detection of the apparatus used. The prognostic significance of detection of circulating prostate cancer cells remains to be clarified, but the detection of these cells and their correlation with the primary tumour will provide a better understanding of metastatic phenomena.

[The PSA gene: value in detection of circulating prostate cancer cells]. / Le gène du PSA: intérêt pour la détection des cellules circulantes dans le cancer de la prostate.

There has been a renewed interest in detection of circulating cancer cells due to the simplicity, specificity and sensitivity of a molecular biology technique: RT-PCR. This detection is based on the concept of specificity of an RNA sequence expressed by a cancer cell. PSA appears to be the ideal marker for circulating prostate cancer cells due to its specificity. The authors review the genes of the kallikrein family and discuss the advantages and difficulties involved in the use of PSA messenger RNA as a marker for circulating prostate cancer cells.

Cloning and sequencing of the equine testicular follitropin receptor.

To investigate the possibility that specific structural determinants within the equine follitropin receptor (eFSHR) are critical to the enhanced specificity of this receptor compared to other FSHRs, we used the RACE-PCR technique to clone the eFSHR from equine testis. Sequence analysis revealed that the eFSHR is highly homologous to other mammal FSHRs, but it presents 10 unique amino acid residue replacements in the extracellular domain. Furthermore, a potential N-glycosylation site was detected at a position not encountered in other receptors. Northern blot analysis identified three transcripts of 4.2 kb, 2.3 kb and 1.0 kb in horse testis.

A method of HLA class II typing using nonradioactive labelled oligonucleotides.

The typing of HLA class II genes using molecular biology techniques has brought undoubtedly new insights in the analysis of their polymorphism. Particularly interesting is the dot-blot analysis of enzymatically-amplified genomic DNA hybridized with sequence-specific oligonucleotides. In order to use this technique of typing on a routine basis, we established a non-radioactive detection method of enzymatically-amplified genomic DNA dot-blots. We could clearly demonstrate that, using biotin-labelled specific oligonucleotides, it was possible to specifically discriminate between DQB1 first domain DNA sequences displaying three, two or even only one base-pair difference at a given codon position. The very satisfactory sensitivity level reached by this non-radioactive detection method could safely allow its use for clinical applications of HLA typing at the DNA level.