Simple, fast method of detection apoptosis in lymphoid cells

Mindray BC-6800 haematological analyser: 3D-DIFF scattergram usefulness in infectious mononucleosis diagnosis

INTRODUCTION

3D-DIFF scattergram of the Mindray BC-6800 haematological analyser shows morphological abnormalities and lymphocyte cluster splitting related to the presence of reactive lymphocytes. This study aims to assess whether these cytographic changes are useful in detecting both activated and apoptotic lymphocytes, leading to an improvement in the laboratory diagnostic process of infectious mononucleosis.

METHODS

Two hundred three samples with modified shape and doubled lymphocyte cluster of DIFF scattergram (study group) were divided into two different subgroups: with and, respectively, without serological evidence of ongoing IM. Activated and apoptotic cells in peripheral blood were counted by light microscopy or gating in the instrumental dot plots. Values of apoptotic cells counted by microscopy were compared with those resulting from gating.

RESULTS

Samples with both shape change and doubled lymphocyte cluster had serological profiles according to the diagnosis of ongoing infectious mononucleosis. Blood smears review was positive for reactive lymphocytes in all 112 samples (100%). An underestimation of apoptotic cell count by light microscopy compared with the gating in the instrumental scatterplot was also observed (96 out of 112, 85.7%).

CONCLUSION

The additional lymphocyte cluster was significantly associated with activated and apoptotic lymphocytes in samples with serology suggesting ongoing infectious mononucleosis. Considering the significance of clue for infectious mononucleosis assigned to the apoptotic lymphocytes, a specific flag such as "apoptotic cells?" could be associate with the related cluster. Such a flag could be used for dedicated rules for smears review, thus increasing infectious mononucleosis detection in laboratories that do not usually practise instrumental cytograms observation.

Detection of Apoptotic Lymphocytes Through Sysmex XN-1000 As a Diagnostic Marker for Mononucleosis Syndrome

BACKGROUND

The infectious mononucleosis (IM) includes clue elements, apoptotic and atypical lymphocytes. In IM, the evaluation of dot plot provided by Sysmex XN-1000 analyzer revealed a stretched lymphocytic cluster, white cell differential channel (WDF), on cytogram.

METHODS

In this study, we analyzed 698 samples that include 39 IM, 76 chronic lymphoproliferative disorders, 25 nonclonal lymphocytosis, and 40 healthy donors. Five hundred eighteen samples with other diseases or interference were evaluated. The algorithm was validated on 40,000 files that were received from internal database of Sysmex-Dasit.

RESULTS

The analysis of flow cytometry standard (FCS) files in WDF channel and presumed apoptotic lymphocytes counts on side scatter/forward scatter (SSC/FSC) and SSC/SFL (where SFL is side fluorescence) dot plot revealed excellent correlation among apoptotic cells on peripheral blood smear (R(2)  = 0.79 and 0.75). There was a variation of positional parameters in lymphocyte clusters WX, WY, and WZ. If WX-SSC > 500 and WY-SFL > 1,000 and WZ-FSC > 700, specificity equals to 99% and sensitivity equals to 100%. If nucleated red blood cell (NRBC) <0.03 × 10(3) /μl, specificity equals to 100%. In received files, positives were 1% adding the simultaneous presence of a percentage of events in the two gates relating to the apoptotic lymphocytes of 1.2% of WBC.

CONCLUSION

On Sysmex XN-1000, dot-plot observation allowed immediate detection of IM. Meanwhile, an algorithm based on the parameters on these plots can be calculated with excellent performance.

Evidence for the mode of action of the highly cytotoxic Streptomyces polyketide kendomycin

The macrocyclic polyketide kendomycin exhibits antiosteoporotic and antibacterial activity, as well as strong cytotoxicity against multiple human tumor cell lines. Despite the promise of this compound in several therapeutic areas, the cellular target(s) of kendomycin have not been identified to date. We have used a number of approaches, including microscopy, proteomics, and bioinformatics, to investigate the mode of action of kendomycin in mammalian cell cultures. In response to kendomycin treatment, human U-937 tumor cells exhibit depolarization of the mitochondrial membrane, caspase 3 activation, and DNA laddering, consistent with induction of the intrinsic apoptotic pathway. To elucidate possible apoptotic triggers, DIGE and MALDI-TOF were used to identify proteins that are differently regulated in U-937 cells relative to controls. Statistical analysis of the proteomics data by the new web-based application GeneTrail highlighted several significant changes in protein expression, most notably among proteasomal regulatory subunits. Overall, the profile of altered expression closely matches that observed with other tumor cell lines in response to proteasome inhibition. Direct assay in vitro further shows that kendomycin inhibits the chymotrypsin-like activity of the rabbit reticulocyte proteasome, with comparable efficacy to the established inhibitor MG-132. We have also demonstrated that ubiquitinylated proteins accumulate in kendomycin-treated U-937 cells, while vacuolization of the endoplasmic reticulum and mitochondrial swelling are induced in a second cell line derived from kangaroo rat epithelial (PtK(2)) cells, phenotypes classically associated with inhibition of the proteasome. This study therefore provides evidence that kendomycin mediates its cytotoxic effects, at least in part, through proteasome inhibition.

Effects of dexamethasone and aminophylline on survival of Jurkat and HL-60 cells

The effects of dexamethasone and aminophylline on survival of Jurkat T-lymphocytic leukemia cells and HL-60 promyelocytic leukemia cells were investigated. Dexamethasone (10, 1000 nM) and aminophylline (1, 100 microM) induced apoptosis in Jurkat and HL-60 cells in a concentration-dependent manner. Treatment with a combination of dexamethasone (10 nM) and aminophylline (1 microM) significantly increased the number of apoptotic HL-60 cells, but not that of Jurkat cells, compared with dexamethasone (10 nM) or aminophylline (1 microM) treatment alone. Dexamethasone and aminophylline also increased the number of phospho-histone H2B (Ser(14))-positive Jurkat and HL-60 cells. Phospho-histone H2B (pH2B)-positive HL-60 cells were significantly increased by treatment with a combination of dexamethasone (10 nM) and aminophylline (1 microM), although no such effect was observed in Jurkat cells. On the other hand, simultaneous treatment with 10 nM dexamethasone and 1 muM aminophylline activated the 36-kDa MBP kinase, pro-apoptotic protein kinase in HL-60 cells. The activation of 36-kDa MBP kinase by dexamethasone and aminophylline was supported by studies showing an increase in the number of pH2B-positive and apoptotic Jurkat and HL-60 cells upon exposure to these drugs. Thus treatment with a combination of dexamethasone and aminophylline accelerates apoptosis of HL-60 cells via activation of 36-kDa MBP kinase and H2B phosphorylation.

Improved detection of minimal acute myeloid leukemia cells by the use of the combined parameters of XE-2100 hematology analyzer

BACKGROUND

For the diagnosis and therapy of acute leukemia, it is important to detect a small number of leukemic cells precisely. Although several automated hematology analyzers that carry blast-detecting programs have been developed, they do not exert sufficient detection sensitivity to exceed the sensitivity of manual eye counting method.

METHODS

We constructed a new blast-detecting program by combining the numerical information acquired from five cytometric parameters presented by XE-2100. The sensitivity and specificity of this blast multi-scoring program were assessed in comparison with the Blasts flag program equipped originally in XE-2100.

RESULTS

The blast-detecting sensitivity was found to be highly improved in the blast multi-scoring program as compared with the Blasts flag program without much decreasing the specificity. A small number of leukemic myeloblasts was detected at the better sensitivity than the eye counting method in the clinical course of the patients with acute myeloid leukemia.

CONCLUSIONS

The daily practical use of this blast multi-scoring program will surely contribute to sensitive, objective, and real-time evaluation of the control of acute myeloid leukemia with a low cost.

Clinical efficacy of irradiation in CLL patients: predictive value of in vitro radio-induced apoptosis

In order to identify CLL patients for whom irradiation could be beneficial, we investigated the relationship between in vitro radio-induced apoptosis of leukemic cells and response to low-dose splenic or lymph node radiotherapy. Fourteen patients were included in the in vitro study. Leukemic cells were analyzed by Hoechst staining immediately after collection or 24h of culture following in vitro irradiation of 0-10 Gy. The tumor response rate was 47% (one CR and six PR), with a mean duration of response of 3 months (range: 1-4). A high correlation between tumor response and in vitro tests was observed (p < 0.01) and the positive predictive value of the in vitro tests for tumor and hematological responses was 100% at 5 Gy. These results suggest that the sensitivity of leukemic cells to irradiation should be first evaluated in an in vitro assay to spare refractory patients from the useless toxicity radiotherapy.

A multicentric study of 41 cases of B-prolymphocytic leukemia: two evolutive forms

B-prolymphocytic leukemia (B-PLL) is an infrequent disease with a poor prognosis. We present the clinical and biological features of 41 patients. Median age was 67 years [42-89] and male-female sex ratio was 2.4. The immunophenotyping revealed B-cell phenotype, with a high level expression of surface IgM and/or IgD in all cases, FMC7+ in 76 % of cases and CD5+ in 67%. Marked spontaneous in-vitro apoptosis was observed in most cases tested (n = 12). The median overall survival time was 5 years and the event-free survival time was 37 months. As detected by univariate and multivariate analysis, the only variables associated with a poor prognosis were advanced age and anemia. No significant difference was observed between de novo PLL (n = 27) and prolymphocytoid transformation of chronic lymphocytic leukemia (n = 14). Two groups of patients were individualized according to their clinical course: patients who died within one year of diagnosis (n = 14) and patients who had a prolonged survival (n = 23) without any treatment in some cases. The comparison between the 2 groups showed that they differed in age (p = 0.01) and anemia (p = 0.02). We also observed that the patients with p53 mutations had a worse clinical outcome. Taken together these data confirm that B-PLL should be regarded as a distinct form of chronic lymphoproliferative disorder and suggest the existence of two patterns of clinical evolution.

Contribution of automated hematology analysis to the detection of apoptosis in peripheral blood lymphocytes

Automated hematology analyzers (analyzers) can provide complete blood counts and white blood cell (WBC) differentials in clinical laboratories and alert users to the presence of quantitative and qualitative cell abnormalities through cautionary flags. In this study, we applied analyzers to the screening of apoptotic cells in peripheral blood and examined the triggering capacity of cautionary flags to detect apoptotic cell populations. EDTA-anticoagulated fresh peripheral blood from patients with acute infectious mononucleosis containing atypical lymphocytes comprising 12.3 +/- 4. 0% of WBC was applied to a Beckman-Coulter MAXM A/L Retic (MAXM) analyzer. The lymphocyte cluster spread upward in VOLUME/DF1 scattergrams and the threshold lines between lymphocyte and monocyte clusters shifted upward. Flags for the number and percentage of lymphocytes, variant lymphocytes, and blast cells were generally present for samples containing atypical lymphocytes. After the blood from acute infectious mononucleosis patients was incubated for 4 h at 37 degrees C, peripheral blood smears revealed the presence of morphologically apoptotic cells comprising 9.0 +/- 4.2% of WBC and a comparable reduction of lymphocytes. On the MAXM analyzer, the apoptotic lymphocyte cluster appeared under the lymphocyte cluster in VOLUME/DF1 scattergrams. However, no specific flag was present to alert users to the presence of the apoptotic lymphocyte cluster. We conclude that visual inspection of scattergrams generated by the MAXM analyzer can be useful for the detection of apoptotic lymphocytes in peripheral blood. Cytometry (Comm. Clin. Cytometry) 42:209-214, 2000. Published 2000 Wiley-Liss, Inc.

A small, dilute-cytoplasm, high-affinity, novel bacterium isolated by extinction culture and having kinetic constants compatible with growth at ambient concentrations of dissolved nutrients in seawater

Dilutions of raw seawater produced a bacterial isolate capable of extended growth in unamended seawater. Its 2.9-Mb genome size and 40-fg dry mass were similar to values for many naturally occurring aquatic organotrophs, but water and DNA comprised a large portion of this small chemoheterotroph, as compared to Escherichia coli. The isolate used only a few aromatic hydrocarbons and acetate, and glucose and amino acid incorporation were entirely absent, although many membrane and cytoplasmic proteins were inducible; it was named Cycloclasticus oligotrophus. A general rate equation that incorporates saturation phenomena into specific affinity theory is derived. It is used to relate the kinetic constants for substrate uptake by the isolate to its cellular proteins. The affinity constant KA for toluene was low at 1.3 microg/liter under optimal conditions, similar to those measured in seawater, and the low value was ascribed to an unknown slow step such as limitation by a cytoplasmic enzyme; KA increased with increasing specific affinities. Specific affinities, a degreess, were protocol sensitive, but under optimal conditions were 47.4 liters/mg of cells/h, the highest reported in the literature and a value sufficient for growth in seawater at concentrations sometimes found. Few rRNA operons, few cytoplasmic proteins, a small genome size, and a small cell size, coupled with a high a degreess and a low solids content and the ability to grow without intentionally added substrate, are consistent with the isolation of a marine bacterium with properties typical of the bulk of those present.