T-cell cytokine responses in human infection with Mycobacterium tuberculosis

Compared with healthy tuberculin reactors, Mycobacterium tuberculosis-stimulated peripheral blood mononuclear cells from tuberculosis patients had diminished production and mRNA expression of the Th1 cytokines gamma interferon and interleukin 2 (IL-2), with no change in production and mRNA expression for the Th2 cytokines IL-4, IL-10, and IL-13. These results were confirmed by evaluation of T cells and CD4+ cells. At the level of systemic T cells, development of tuberculosis is associated with diminished Th1 but not enhanced Th2 responses.

Induction of apoptosis by 5-azacytidine: drug concentration-dependent differences in cell cycle specificity

There are conflicting data in the literature as to whether cytotoxicity of the cytidine antimetabolite 5'-azacytidine (AZC) is a consequence of its incorporation into RNA, DNA, or both. Because apoptosis appears to be the predominant mode of tumor cell death after treatment with most antitumor drugs, and in the case of some drugs, the proclivity of the cell to undergo apoptosis varies depending on the cell cycle position, this study was aimed toward elucidating whether induction of apoptosis by AZC is cell cycle phase specific. Human promyelocytic leukemic HL-60 cells were treated with varying concentrations of AZC, and flow cytometric methods that identify apoptotic cels and provide information about the cell cycle distribution of the apoptotic and nonapoptotic cell populations were used. At 2-6 microM concentrations of AZC, the cells in the G1 phase preferentially underwent apoptosis, whereas the cells in G2-M were particularly resistant. Although incorporation of bromouridine into RNA was suppressed at that low AZC concentration, the rate of 5'-bromo-2-deoxyuridine incorporation into DNA was not significantly affected. At an AZC concentration of 8-40 microM, no cell cycle phase specificity in induction of apoptosis was apparent, but both the rate of 5'-bromo-2-deoxyuridine incorporation into DNA and bromouridine into RNA were reduced in proportion to drug concentration. The data suggest that the mechanism of cell killing by AZC may be different, depending on its concentration. Namely, whereas incorporation of AZC into RNA may play a predominant role in the induction of cytotoxicity of G1 cells at low drug concentrations, the perturbation of both RNA and DNA metabolism may be responsible for triggering cell death in the G1 and S phases, as is seen at higher concentrations of this antimetabolite.

Autocrine transforming growth factor beta 1 modulates the expression of integrin alpha 5 beta 1 in human colon carcinoma FET cells

Transforming growth factor beta (TGF-beta) has been extensively studied as an exogenous agent that stimulates the expression of extracellular matrix proteins and their cell-surface integrin receptors in a variety of cell types. However, the recent demonstration of autocrine TGF-beta growth effects in a number of cell types suggests that the steady-state expression of extracellular matrix and integrin proteins and their biological activity may also be under autocrine TGF-beta control. Previously, we reported that repression of autocrine TGF-beta 1 activity by constitutive expression of a full-length TGF-beta 1 antisense cDNA led to abrogation of autocrine negative TGF-beta and, as a result, increased tumorigenicity and anchorage-independent growth of a poorly tumorigenic, well-differentiated colon carcinoma cell line designated FET (Wu, S., Theodorescu, D., Kerbel, R. S., Willson, J. K. V., Mulder, K. M., Humphrey, L. E., and Brattain, M. G. (1992) J. Cell Biol. 116, 187-196). Consequently, we have used this model system to study the effects of repression of autocrine TGF-beta 1 activity on the expression of integrin alpha 5 beta 1 and integrin alpha 5 beta 1-mediated cell adhesion to fibronectin. The expression of the integrin alpha 5 subunit was reduced in TGF-beta 1 antisense transfected FET cells at both mRNA and protein levels as determined by RNase protection assays and immunoprecipitation, respectively. Autocrine TGF-beta 1 had no effect on the transcription of integrin alpha 5 and beta 1 subunits, indicating that autocrine TGF-beta 1 may regulate integrin alpha 5 beta 1 expression at the post-transcriptional level. The diminished expression of integrin alpha 5 beta 1 on the cell surface led to the reduced adhesion of TGF-beta 1 antisense transfected cells to fibronectin. This phenomenon could be reversed by treatment with exogenous TGF-beta 1.

Shall red cell units stand upright, lie flat or be mixed during storage? In vitro studies of red cells collected in 0.5 CPD and stored in RAS2 (Erythrosol)

Red cells were prepared using a new anticoagulant with half the normal amount of citrate and a new additive solution (RAS2, Erythrosol) previously shown to give improved storage conditions, and stored in a highly gas permeable plastic container (PL 2209). Mixing daily and weekly resulted in lower PCO2, higher PO2 and more rapid oxygen saturation of the haemoglobin than storage unmixed in an upright position. Storage horizontally in a lying position unmixed resulted in similar blood gas values as with mixing. The haemolysis was lowest in units mixed once weekly: 0.21 +/- 0.09% after 28 days and 0.26 +/- 0.06% after 56 days. The morphology was better maintained in mixed than in unmixed units. Horizontal storage and mixing once per week seem to be optimal as judged from these in vitro studies.

Threshold expression of cyclin E but not D type cyclins characterizes normal and tumour cells entering S phase

Complexes of cyclin-dependent kinases (cdk) and their partner cyclins drive the cell through the cell cycle, each such complex phosphorylating a distinct set of proteins at a particular check-point or phase of the cycle. Immunocytochemical detection of cyclins combined with measurement of cellular DNA content by flow cytometry makes it possible to relate expression of each of these proteins with the actual cell cycle position, without the necessity of cell synchronization. In the present study, we have investigated expression of E and D type cyclins in G1 cells and in cells entering S phase, in eight different human hematopoietic and solid tumour cell lines (two leukaemias, a lymphoma, three breast carcinomas, a colon carcinoma and a bladder transitional cell carcinoma) during their exponential phase of growth, as well as in normal mitogen stimulated lymphocytes. In all the cell types studied, the average level of D type cyclin expression was invariable throughout the cell cycle. A great intercellular variability, in particular of the G1 cell subpopulations, and the presence of a large fraction of G1, S and G2 + M cells that were cyclin D negative (20-40% in tumour cell lines and about 80% among lymphocytes), were other characteristic features of D type cyclin expression. In contrast to D type cyclins, the expression of cyclin E was discontinuous during the cycle, peaking at the time of cell entrance to S. Also, a well defined threshold in expression of cyclin E characterized cells that were entering S phase, and virtually no cyclin E negative cells were seen during the early portion of S phase. The data indicate that while cell entrance to S phase is unrelated to expression of D type cyclins (at the time of entrance), accumulation of cyclin E up to critical level is a prerequisite for initiation of DNA replication. The great intercellular variability in expression of D type cyclins and their invariant average level across the cell cycle suggest that these cyclins, in addition to their acknowledged function in promoting cell progression through mid- to late-G1 may have other role(s), related or unrelated to the cell cycle progression. The presence of a large number of D type cyclin negative cells in all phases of the cycle suggests that during exponential growth the cells may not express this protein and yet may traverse the cycle, including G1 phase.

Expression of cyclins A, D2 and D3 in individual normal mitogen stimulated lymphocytes and in MOLT-4 leukemic cells analyzed by multiparameter flow cytometry

Cyclins are regulatory subunits of the cyclin dependent kinases (CDKs), the enzymes that drive the cell through the respective phases and check-points of the cell cycle. The expression of cyclins in non-tumor cells, regulated by timely induction of their synthesis and proteolysis, is scheduled, occurring at discrete periods of the cell cycle. Using multiparameter flow cytometry we have recently observed that expression of cyclins B1 and E in individual normal lymphocytes mitogenically stimulated by phytohemagglutinin (PHA) and lymphocytic leukemic MOLT-4 cells was similar, restricted to particular phases of the cycle: cyclin B1 was detected only in G2+M- and cyclin E in late G1 and early S-phase cells. In the present study we have measured the expression of cyclins A, D2 and D3 in these cells. The presence of cyclin A was restricted to late S and G2 phases, both in the case of lymphocytes and of MOLT-4 cells. Over 95% of the non-stimulated lymphocytes were both cyclin D2 and D3 negative. Mitogenic stimulation with PHA-induced expression of cyclins D2 and D3 in over 50% cells, which corresponds to the percentage of cells that respond to this mitogen in cultures. Expression of these proteins peaked between 8 and 24 h after addition of PHA, and then decreased at the time of cell entrance to S. During exponential growth (48-72 h after stimulation with PHA) expression of the D-type cyclins was diminished: only between 5-10% of the lymphocytes had levels of cyclin D3 as high as G1 cells between 8-24 h after PHA stimulation. Populations of proliferating lymphocytes and MOLT-4 cells were very heterogeneous in terms of expression of D-type cyclins by individual cells. While expression of cyclin D2 in exponentially growing MOLT-4 cells was similar to that of proliferating lymphocytes, the percent of cells expressing cyclin D3 as well as the degree of expression, was higher in MOLT-4 cells, regardless of the phase of the cycle. These results, with our earlier observations of the untimely expression of cyclins B1 and E in several other tumor lines, suggest that altered expression of cyclins may be a frequent feature of malignancy.

5-Aminolevulinate synthase and the first step of heme biosynthesis

5-Aminolevulinate synthase catalyzes the condensation of glycine and succinyl-CoA to yield 5-aminolevulinate. In animals, fungi, and some bacteria, 5-aminolevulinate synthase is the first enzyme of the heme biosynthetic pathway. Mutations on the human erythroid 5-aminolevulinate synthase, which is localized on the X-chromosome, have been associated with X-linked sideroblastic anemia. Recent biochemical and molecular biological developments provide important insights into the structure and function of this enzyme. In animals, two aminolevulinate synthase genes, one housekeeping and one erythroid-specific, have been identified. In addition, the isolation of 5-aminolevulinate synthase genomic and cDNA clones have permitted the development of expression systems, which have tremendously increased the yields of purified enzyme, facilitating structural and functional studies. A lysine residue has been identified as the residue involved in the Schiff base linkage of the pyridoxal 5'-phosphate cofactor, and the catalytic domain has been assigned to the C-terminus of the enzyme. A conserved glycine-rich motif, common to all aminolevulinate synthases, has been proposed to be at the pyridoxal 5'-phosphate-binding site. A heme-regulatory motif, present in the presequences of 5-aminolevulinate synthase precursors, has been shown to mediate the inhibition of the mitochondrial import of the precursor proteins in the presence of heme. Finally, the regulatory mechanisms, exerted by an iron-responsive element binding protein, during the translation of erythroid 5-aminolevulinate synthase mRNA, are discussed in relation to heme biosynthesis.

Aminolevulinate synthase: functionally important residues at a glycine loop, a putative pyridoxal phosphate cofactor-binding site

5-Aminolevulinate synthase catalyzes the first step of the heme biosynthetic pathway in nonplant higher eukaryotes. The enzyme functions as a homodimer and requires pyridoxal 5'-phosphate as its cofactor. Lysine-313 in murine erythroid aminolevulinate synthase has been identified as the residue involved in the Schiff base linkage with pyridoxal 5'-phosphate [Ferreira, G. C., Neame, P. J., & Dailey, H. A. (1993) Protein Sci. 2, 1959-1965]. However, other residues involved in binding and orienting the cofactor remain unknown. We studied the informational content of each residue within an 11 amino acid glycine-rich region, which we propose to be part of the phosphate-binding motif, based on amino acid sequence comparison with other pyridoxal 5'-phosphate-dependent enzymes and nucleotide-binding proteins. Partial random mutagenesis of this region in murine erythroid aminolevulinate synthase gene was followed by an efficient biological selection, using a hemA- Escherichia coli strain to recover functional unnatural enzymes. Among the total of 5444 variants produced, 283 were found to be functional. DNA sequencing results of 226 functional mutants indicated that most residues in this region contained a low informational content, being able to tolerate several other amino acid substitutions. However, three residues, namely, Arg-149, Gly-142, and Gly-144, were found to contain high informational content; Arg-149 was conserved in all of the functional mutants sequenced, while Gly-142 and Gly-144 could only tolerate alanine replacement. Two codon-specific random libraries of Arg-149, and Gly-142 and -144, respectively, were constructed to test further the stringency of these three positions.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging and dietary modulation of elastase and interleukin-1 beta secretion

Aging is associated with diminished immune function that may stem from alterations in arachidonic acid metabolism and lipid peroxidation. This study sought to determine if dietary modification of fatty acids influenced neutrophil and monocyte secretion after an in vivo inflammatory stress in older human subjects. Volunteers participated in protocols that forced their quadriceps muscles to lengthen during tension development (eccentric stress). These protocols can cause inflammatory foci in the muscle as well as alterations in circulating leukocyte function. In this study, in vivo neutrophil degranulation was assessed by plasma elastase concentrations, and mononuclear cell function was assessed by interleukin-1 beta (IL-1 beta) secretion in vitro. In response to eccentric stress, older subjects (> 60 yr old) taking a placebo had no apparent elastase response, whereas those taking fish oil supplements responded with a 142% increase in plasma elastase (P = 0.011), similar to responses of younger reference subjects (< 33 yr old) taking no supplement. Overall, elastase responses correlated with individual plasma arachidonic acid-to-eicosapentaenoic acid ratios (r = -0.881, P = 0.004). Thus apparent age-related differences in elastase release were reconciled by individual differences in fatty acid nutriture. No significant temporal changes in urinary lipid peroxide excretion or IL-1 beta secretion were observed; however, age-associated differences were found.

T cell cytokine responses in persons with tuberculosis and human immunodeficiency virus infection

Tuberculosis causes more extensive and life-threatening disease in patients with HIV infection than in immunocompetent persons. To investigate the hypothesis that these severe manifestations of tuberculosis may be due to alterations in cytokine production, we evaluated cytokine patterns in HIV-infected tuberculosis patients. Upon stimulation with Mycobacterium tuberculosis in vitro, PBMC from HIV-infected tuberculosis patients had reduced proliferative and type 1 responses, compared with HIV-seronegative tuberculosis patients. The reduction in proliferative responses was independent of the CD4 cell count, but the reduced type 1 response was a direct result of CD4 cell depletion. There was no enhancement of type 2 cytokine production in HIV-infected patients, although production of IL-10 was prominent in all tuberculosis patients. In HIV-infected tuberculosis patients, M. tuberculosis-induced proliferative responses were significantly enhanced by neutralizing antibodies to IL-10 but not by antibodies to IL-4 or by recombinant IL-12. The M. tuberculosis-induced type 1 response was augmented both by antibodies to IL-10 and by recombinant IL-12. Tuberculosis in the context of HIV infection is characterized by diminished type 1 responses, probably induced by immunosuppressive cytokines produced by macrophages/monocytes, rather than by type 2 cells.

Studies of one invasive and two noninvasive methods for detection of bacterial contamination of platelet concentrates

Recently, a new method for noninvasive detection of bacterial contamination of platelet concentrates was described [Arpi et al.: Vox Sang 1993;65:335-336]. A CO2-sensitive label is applied on the outer surface of the plastic container of the platelet concentrate. When any contaminating bacteria have increased the pCO2 to a certain level the label changes color, indicating bacterial growth. We have studied this technique and applied such sensitive labels both directly onto PCs and onto plastic bags with culture medium into which platelet contents have been transferred. However, in both cases the sensitivity of the technique was found insufficient for practical quality control of PCs. There seem to be two problems with this principle: (1) platelets produce CO2 and (2) a considerable amount of the gas passes beside the detection label, in this way decreasing the sensitivity of detection by the label. This noninvasive technique was compared with an invasive method using automated bacterial culture, which was found sensitive and rapid.

Unscheduled expression of cyclin B1 and cyclin E in several leukemic and solid tumor cell lines

Normal, nontumorous cells express cyclin proteins in an orderly, scheduled fashion, at a given phase of the cell cycle. Thus, cyclin B1 is synthesized during G2 and abruptly degraded during mitosis. The onset of cyclin E synthesis takes place in mid-G1, its maximal expression is at the time of cell entrance to S, and its degradation occurs during cell progression through S phase. In the present study, multiparameter flow cytometry was used to correlate expression of cyclin B1 or cyclin E with cell cycle position (estimated by cellular DNA content) in normal human proliferating lymphocytes as well as in T-cell MOLT-4 leukemia; promyelocytic HL-60 leukemia; histiocytic U937 lymphoma; MCF-7, T-47D, and Hs 587T breast carcinoma; Colo 320DM colon carcinoma; and the T-24 transitional cell carcinoma cell line. The scheduled expression of both cyclins, namely of cyclin B1 restricted to G2 + M cells and of cyclin E restricted to late G1 and early S cells, was observed only in normal lymphocytes and MOLT-4 cells. The cells of HL-60, U937, T-47D, and Hs 587T lines expressed both cyclins in an unscheduled ("ectopic") fashion, i.e., unrelated to cell cycle position. Colo 320DM cells showed unscheduled expression of cyclin E (i.e., during G2) but expression of cyclin B1 in this line was generally restricted to G2 + M cells. There were relatively few (10-12%) cells in MCF-7 and T-24 cell lines that expressed cyclin B1 or E in an unscheduled manner. It may be expected that the unscheduled expression of cyclins in tumor cells may lead to a loss of the regulatory mechanisms of cell cycle progression and that such feature of the tumor may be of prognostic value. There is a need, therefore, to conduct similar studies in primary tumor cells.

Staurosporine blocks cell progression through G1 between the cyclin D and cyclin E restriction points

The protein kinase inhibitor staurosporine (SSP) stops progression of normal nontransformed cells in the G1 phase of the cell cycle. This implies that at least one of the cell cycle associated kinases, essential for cell transit through G1, is sensitive to SSP. Using multivariate flow cytometry to correlate the expression of cyclin E or cyclin D with cellular DNA content (i.e., cell cycle position), we have presently characterized the point of action of SSP in relation to the expression of these cyclins. During stimulation of normal human lymphocytes by phytohemagglutinin, cyclin D was expressed early, peaking at 8-14 h, while cyclin E appeared later, reaching a maximum at the time of cell entrance to S phase (24 h). Addition of SSP at the time of cell stimulation, while markedly suppressing the expression of cyclin E, had a rather modest effect on the expression of cyclin D. The data indicate that the SSP sensitive kinase(s) involved in cell progression through G1 operate beyond the restriction point of cyclin D but prior to that of cyclin E. Thus, the target(s) of SSP is (are) either the p33cdk/cyclin E complex itself or other protein kinase(s), activated subsequent to the cyclin D but prior to the cyclin E restriction point, the activity of which is essential for cell transit through G1.

A selective procedure for DNA extraction from apoptotic cells applicable for gel electrophoresis and flow cytometry

In cells undergoing apoptosis (programmed cell death), a fraction of nuclear DNA is fragmented to the size equivalent of DNA in mono- or oligonucleosomes. When such DNA is analyzed by agarose gel electrophoresis it generates the characteristic "ladder" pattern of discontinuous DNA fragments. Such a pattern of DNA degradation generally serves as a marker of the apoptotic mode of cell death. We developed a simple, rapid, and selective procedure for extraction of the degraded, low-molecular-weight DNA from apoptotic cells. The cells are prefixed in 70% ethanol, DNA is extracted with 0.2 M phosphate-citrate buffer at pH 7.8, and the extract is sequentially treated with RNase A and proteinase K and then subjected to electrophoresis. The ladder pattern was detected from DNA extracted from 1-2 x 10(6) HL-60 cells, of which as few as 8% were apoptotic, by flow cytometric criteria, as well as from blood and bone marrow samples from leukemic patients undergoing chemotherapy. The method is rapid and uses nontoxic reagents (no phenol, chloroform, etc.). This approach permits the analysis of DNA extracted from the very same cell population that is subjected to measurements by flow cytometry to estimate DNA ploidy, the cell cycle distribution of nonapoptotic cells, the percentage of apoptotic cells, or other parameters. Furthermore, the cells may be stored in 70% ethanol for at least several weeks before analysis without any significant DNA degradation. Treatment with ethanol also inactivates several pathogens, thereby increasing the safety of sample handling. The method is applicable to clinical samples, which can be fixed in ethanol and then stored and/or safety transported prior to analysis.

Interleukin 12 at the site of disease in tuberculosis

Interleukin 12 (IL-12), a heterodimeric cytokine composed of p40 and p35 chains, has potent immunologic effects in vitro. We used tuberculous pleuritis as a model to study the immunoregulatory potential of IL-12 in vivo at the site of human infectious disease. Messenger RNAs for p40 and p35 were detected in pleural fluid from six of six patients by reverse-transcription polymerase chain reaction. By using an ELISA that detected both free p40 and heterodimeric IL-12, we found that mean concentrations were 585 +/- 89 pg/ml in pleural fluid of patients with tuberculous pleuritis, which were significantly higher than those in serum of the same patients (54 +/- 36 pg/ml), or in malignant pleural effusions (123 +/- 35 pg/ml). By using an ELISA specific for heterodimeric IL-12, we found that mean concentrations in pleural fluid of patients with tuberculous pleuritis were 165 +/- 28 pg/ml and undetectable in serum of the same patients, or in malignant pleural effusions. Bioactive IL-12 was detectable in five of five supernatants of pleural fluid cells stimulated with Mycobacterium tuberculosis. Addition of anti-IL-12 antibodies suppressed proliferative responses of pleural fluid cells to M. tuberculosis by 36 +/- 7%. These data indicate that IL-12 may play a role in the human immune response to infectious agents in vivo. We hypothesize that IL-12 contributes to the antimycobacterial immune response by enhancing production of interferon-gamma, facilitating development of Th1 cells and augmenting cytotoxicity of antigen-specific T cells and natural killer cells.

Complement killing of Yersinia enterocolitica and retention of the bacteria by leucocyte removal filters

We report studies on the complement sensitivity of four strains of Yersinia enterocolitica, serotypes O:3, O:9, O:5.27, and O:20, isolated from blood units involved in transfusion fatalities. Complement in fresh CPD plasma killed Y. enterocolitica within 4 h at 22 degrees C in 100% of the experiments. The bactericidal action was serotype and complement activation pathway dependent. Both classic and alternate pathways seemed to be active, but the latter to a lesser degree. When the classic pathway was blocked by chelation of Ca2+ no complete killing was obtained. Complement did not enhance or condition Yersinia for leucocyte filter retention. Direct removal of Yersinia by filtration was also related to serotype; all strains were reduced by filtration in heat-inactivated plasma, and all except serotype O:5.27 were reduced in Ca(2+)-chelated plasma. Our findings may explain why plasma products and platelet concentrates are rarely involved in Yersinia sepsis related to transfusion.

Use of the cyclin e restriction point to map cell arrest in g(1)-induced by N-butyrate, cycloheximide, staurosporine, lovastatin, mimosine and quercetin

Cyclin E, a member of the G1 cyclin family, is an integral component of the complex machinery of the cell cycle. This protein is synthesized late in the G1 phase of the cycle and its transient association with p33cdk2 is essential for cell entrance to S phase. Using bivariate DNA content - cyclin E expression flow cytometric analysis, we have compared the point of action in G1 of several agents with diverse mechanisms of action in terms of its relationship to the cyclin E restriction point: cell arrest prior to the onset of cyclin E synthesis was expected to result in accumulation of cyclin E negative cells (G1cyE-) whereas arrest past this point was expected to result in accumulation of G1 cells with an increased cyclin E content (G1cyE+). Incubation of MOLT-4 cells with n-butyrate (which induces hyperacetylation of histones and hypophosphorylation of histone H1) and the protein synthesis inhibitor cycloheximide arrested them in G1cyE. Likewise. incubation of c-ras transformed bladder carcinoma T24 cells with lovastatin (presumed to interfere with isoprenylation of p21ras and thus affecting the signal transduction pathway), or normal mitogen stimulated human lymphocytes with staurosporine (a protein kinase inhibitor) led to cell arrest in G1cyE. In contrast, growth of MOLT-4 cells in the presence of the bioflavonoid quercetin or plant amino acid mimosine, resulted in their arrest at the G, point past the onset of cyclin E synthesis (G1cyE+). Mapping the point(s) of action of drugs that perturb progression in the cycle with respect to the onset of synthesis of cyclin proteins offers some advantages compared to temporal mapping; the latter may vary due to intrinsic differences between cell types in the duration of G1, the induction of unbalanced growth, etc.

Effect of staurosporine on MOLT-4 cell progression through G2 and on cytokinesis

Staurosporine (SSP) is an inhibitor of a variety of protein kinases with an especially high affinity towards protein kinase C. Whereas SSP has been shown to halt the cell cycle progression of various normal, nontransformed cell types in G1, most virus transformed or tumor cells are unaffected in G1 but arrest in G2 phase. SSP has also been observed to increase the appearance of cells with higher DNA content, suggestive of endoreduplication, in cultures of tumor cells. Using multivariate flow cytometry (DNA content vs. expression of cyclin B, nuclear p120 protein, or protein reactive with Ki-67 antibody) which makes it possible to discriminate cells with identical DNA content but at different phases of the cycle, we have studied the cell cycle progression of human lymphocytic leukemic MOLT-4 cells in the presence of 0.1 microM SSP. MOLT-4 cells did not arrest in G1 or G2 phase in the presence of the inhibitor. Rather, they failed to undergo cytokinesis, entering G1 phase at higher DNA ploidy (tetraploidy; G1T), and then progressed through ST (rereplication) into G2T and MT. The rates of entrance to G2 and G2T were essentially identical, indicating that the rates of cell progression through S and ST as well as through G2 and G2T, respectively, were similar. Cells entrance to mitosis and mitotic chromatin condensation were also similar at the diploid and tetraploid DNA content level and were unaffected by 0.1 microM SSP. No evidence of growth imbalance (altered protein or RNA to DNA ratio) was observed in the case of tetraploid cells. The data show that, in the case of MOLT-4 cells, all events associated with the chromosome or DNA cycle were unaffected by SSP; the only target of the inhibitor appears to be kinase(s) controlling cytokinesis.

Flow cytometric detection of apoptosis: comparison of the assays of in situ DNA degradation and chromatin changes

The aim of this study was to compare three methods of detection of apoptotic cells: (1) the method based on elution of low molecular weight DNA from the ethanol fixed cells followed by cell staining with DAPI (diamidino-2-phenylindole) or propidium iodide as the DNA fluorochromes, (2) the method of in situ labeling of DNA strand breaks with biotinylated dUTP, utilizing exogenous terminal deoxyribonucleotide transferase, and (3) the method of analysis of DNA denaturation in situ using acridine orange to differentially stain denatured and double-stranded DNA sections following cell exposure to 0.1 M HCl. Cells of the human promyelocytic HL-60 line, treated in vitro with the DNA topoisomerase I inhibitor camptothecin, which selectively triggers apoptosis of S-phase cells, were chosen as a model. The method based on analysis of changes in DNA denaturability was the most sensitive in terms of detection of the earliest changes in chromatin of cells undergoing apoptosis; the increased sensitivity of DNA to denaturation in S-phase cells was measured as early as 100 min after addition of camptothecin. DNA cleavage, assayed either by the univariate measurement of DNA content following extraction of low molecular weight DNA, or by labeling DNA strand breaks with biotinylated dUTP, was detected in S-phase cells after 120 min incubation with camptothecin. The percentage of apoptotic cells at the late stage of apoptosis, the kinetics of cell transition to apoptosis, and kinetics of the loss of S phase cells were all essentially similar when measured by any method.(ABSTRACT TRUNCATED AT 250 WORDS)

Apoptotic cell death during treatment of leukemias

The apoptosis-associated DNA strand breaks were detected in situ, in individual leukemic cells in peripheral blood and bone marrow of over 110 patients with different types of leukemia (ALL, AML, CML in blastic crisis, APL), prior to and during routine chemotherapy. The DNA strand breaks were labeled with digoxigenin- or biotin-conjugated dUTP in the reaction catalyzed by exogenous terminal deoxynucleotidyl transferase, and the cells, counterstained for DNA, were analyzed by bivariate flow cytometry. The proportion of cells with DNA strand breaks prior to therapy, most likely reflecting spontaneous apoptosis, varied from 0.1 to 16%, but in the large majority of cases was below 3%. Administration of drugs of different classes, which included DNA topoisomerase I (Topotecan) and II (mitoxantrone, VP-16) inhibitors, antimetabolite (ara-C) or microtubule poison (Taxol), all triggered the appearance of cells with extensive DNA breakage, typical of apoptosis, to up to 80%. The peak of the response, measured as maximal percent of cells with DNA strand breaks, which varied between individual patients by as much as factor 10, was generally seen between 8 to 24 h after the initial administration of DNA topoisomerase inhibitors, and somewhat later (48-72 h) during the response to Taxol or ara-C. Thus, the data show that the response to treatment with a variety of drugs, in terms of induction of apoptosis, can be conveniently measured by the present method. The prognostic value of the apoptotic index, before, as well as during treatment, is being estimated for each type of leukemia, in the ongoing prospective studies.

Novel automated microbial screening of platelet concentrates

The recovery of bacteria and the speed of detection of microbial growth in platelet concentrates (PC) were studied, comparing a novel automated blood culture system (BacT/Alert) with two traditional methods. Full-scale experiments were performed with a total of 33 units of PC (average content 320 x 10(9) platelets per unit) obtained from pooled buffy coats. Six strains known as possible PC contaminants were tested: S. epidermidis, S. aureus, P. aeruginosa, B. cereus, E. aerogenes, and S. sanguis. Using an inoculum of 50-98 bacteria/ml, bacterial contamination was detected in all of 11 PCs on 132 sampling occasions. With a small inoculum (0.3-9 bacteria/ml), the bacterial contamination was detected in all PCs in which abundant growth appeared, but failed to be detected in some instances where the bacterial content was very small. All of 11 uninoculated PC controls were negative. With the automated method the time for detection of a culture-positive PC was 6-16 h, clearly shorter than with the two manual-visual systems. The new system provides a rapid, reliable, and labour-saving method for screening of bacterial contamination in PCs. This would increase safety particularly if the present 5-day shelf life were extended.

Expression of cyclins-B and cyclins-e in individual molt-4 cells and in stimulated human-lymphocytes during their progression through the cell-cycle

Cyclins B (B1) and E, integral components of the cell cycle drive machinery consisting of p34cdc2 and p33cdk2 cyclin-dependent kinases and their regulatory kinases and phosphatases, were detected in human leukemic MOLT-4 cells and in mitogen-stimulated normal peripheral blood lymphocytes immunocytochemically, using commercially available antibodies. Flow cytometric bivariate analysis of DNA content and cyclin B or E made it possible to correlate expression of these proteins in individual cells with their position in the cycle, without the necessity for cell synchronization. In both cell systems, cyclin B was expressed almost exclusively in G2 and M cells: cells in G1 and throughout most of S phase, were negative. Cells arrested in G2 by gamma radiation or the DNA topoisomerase II inhibitor m-AMSA for up to 4 h, had very high levels of cyclin B. Cells arrested in metaphase by vinblastine also strongly expressed cyclin B, although to a lesser degree than cells arrested in G2. Expression of cyclin E was maximal in late G1 and in early S, while its expression progressively decreased during the remainder of S phase. Two compartments of the G1 phase, G1A and G1B representing cells that were cyclin E negative and positive, respectively, were discriminated. The kinetics of cell exit from G1A, under conditions of stathmokinesis induced by vinblastine, showed a stochastic component; the half-time of MOLT-4 cell residence in G1A was 5.6 h. Nonstimulated (G0) lymphocytes did not express cyclin E; their stimulation by phytohemagglutinin led to the appearance of a subpopulation of cyclin E positive cells as early as 18 h after addition of the mitogen. Maximal expression of cyclin E occurred in G1 lymphocytes just prior to cell entrance to S, and in early S phase cells. Thus, expression of cyclin E can be used as a marker of lymphocyte stimulation (G0 to G1 transition). The combined use of cyclin B and E antibodies can identify late G1, S and G2+M cells, and thus it may be applied to measure the fraction of cycling cells in cell populations, e.g. the tumor growth fraction.

Separation of outer and cytoplasmic membranes of Fibrobacter succinogenes and membrane and glycogen granule locations of glycanases and cellobiase

The outer membrane (OM) of Fibrobacter succinogenes was isolated by a combination of salt, sucrose, and water washes from whole cells grown on either glucose or cellulose. The cytoplasmic membrane (CM) was isolated from OM-depleted cells after disruption with a French press. The OM and membrane vesicles isolated from the extracellular culture fluid of cellulose-grown cells had a higher density, much lower succinate dehydrogenase activity, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis protein profiles different from those of the CM. The OM from both glucose- and cellulose-grown cells and the extracellular membrane vesicles from cellulose-grown cultures exhibited higher endoglucanase, xylanase, and acetylesterase activities than the CM and other cell fractions. Endoglucanase 2 was absent from the isolated OM fractions of glucose- and cellulose-grown cells and from the extracellular membrane vesicles of cellulose-grown cells but was present in the CM and intracellular glycogen granule fractions, while endoglucanase 3 was enriched in the OM. Cellobiosidase was located primarily in the periplasm as previously reported, while cellobiase was mainly present in the glycogen granule fraction of glucose-grown cells and in a nongranular glycogen and CM complex in cellulose-grown cells. The cellobiase was not eluted from glycogen granules by cellobiose, maltose, and maltotriose nor from either the granules or the cell membranes by nondenaturing detergents but was eluted from both glycogen granules and cell membranes by high concentrations of salts. The eluted cellobiase rebound almost quantitatively when diluted and mixed with purified glycogen granules but exhibited a low affinity for Avicel cellulose. Thus, we have documented a method for isolation of OM from F. succinogenes, identified the OM origin of the extracellular membrane vesicles, and located glycanases and cellobiase in membrane and glycogen fractions.

Different patterns of apoptosis of HL-60 cells induced by cycloheximide and camptothecin

Cells of the human promyelocytic HL-60 line, when treated with a variety of antitumor agents in the presence of the protein synthesis inhibitor cycloheximide (CHX), or with CHX alone, rapidly undergo apoptosis ("active cell death"). It is presumed, therefore, that such cells are "primed" to apoptosis in that no new protein synthesis is required for induction of their death. We have studied apoptosis of HL-60 cells triggered by the DNA topoisomerase I inhibitor camptothecin (CAM) in the absence and presence of CHX and apoptosis induced by CHX alone. Two different flow cytometric methods were used, each allowing us to relate the apoptosis-associated DNA degradation to the cell cycle position. Apoptosis induced by CAM was limited to S phase cells, e.g., at a CAM concentration of 0.15 microM, nearly 90% of the S phase cells underwent apoptosis after 4 h. In contrast, apoptosis triggered by CHX was indiscriminate, affecting all phases of the cycle: approximately 40% of the cells from each phase the cycle underwent apoptosis at 5 microM CHX concentration. When CAM and CHX were added together, the pattern of apoptosis resembled that of cycloheximide alone, namely, cells in all phases of the cycle in similar proportion were affected. Thus, CHX, while itself inducing apoptosis of a fraction of cells, protected the S phase cells against apoptosis triggered by CAM. Because CHX (5 microM) did not significantly affect the rate of cell progression through S phase, the observed protective effect was most likely directly related to inhibition of protein synthesis, rather than to its possible indirect effect on DNA replication. Furthermore, whereas apoptosis (DNA degradation) triggered by CAM was prevented by the serine protease inhibitor N-tosyl-L-lysylchloromethyl ketone (TLCK), this process was actually potentiated by this inhibitor when induced by CHX. The present data indicate differences in mechanism of apoptosis triggered by CAM (and perhaps other antitumor drugs) as compared with CHX. Apoptosis caused by CHX may be unique in that it may not involve new protein synthesis. These data are compatible with the assumption that the loss of a hypothetical, rapidly turning over suppressor of apoptosis may be the trigger of apoptosis of HL-60 cells treated with CHX, whereas de novo protein synthesis is required when apoptosis is triggered by other agents.

Half-strength citrate CPD combined with a new additive solution for improved storage of red blood cells suitable for clinical use

Currently used systems for red blood cell (RBC) collection and storage for transfusion have the disadvantage that the RBC 2,3-bisphosphoglycerate (BPG) concentration is depleted within two weeks of storage, resulting in a left-shift of the oxygen dissociation curve and a temporarily impaired capacity to deliver oxygen. We have studied the effects on red cell metabolism, morphology and in vivo recovery of 49-day storage of RBC, with collection in half-strength citrate CPD (0.5CPD) and storage in an additive solution containing citrate, adenine, mannitol, phosphate and glucose (RAS2). Traditional CPD-SAGM was used for comparison. Component preparation was performed after an initial holding period of the whole blood at ambient temperature for 8 h. The BPG concentration in 0.5CPD-RAS2 RBC was 0.633 +/- 0.120 mol (mol Hb)-1 as compared to 0.454 +/- 0.138 mol (mol Hb)-1 in CPD-SAGM RBC which implied a decrease to 67 and 48% of normal concentration, respectively. The mean RBC BPG concentration was maintained at the initial level for 28 days in the new system but decreased to very low levels within 14 days in the controls. The total adenine nucleotides were well maintained in both systems, adenosine triphosphate slightly better in the new system. Hemolysis after 49 days was 0.35 +/- 0.21% in the new system and 0.72 +/- 0.25% in the controls (p < 0.001). The morphology was better maintained in the new system (p < 0.001). The 24-hour posttransfusion survival of 49-day stored RBC was 78.9 +/- 7.1%. The membrane leakage of sodium and potassium was not significantly different in the two systems.(ABSTRACT TRUNCATED AT 250 WORDS)

Simultaneous analysis of cell cycle kinetics at two different DNA ploidy levels based on DNA content and cyclin B measurements

The methods of cell cycle analysis that rely on DNA content measurements cannot discriminate between cells at different phases of the cycle if these cells have similar DNA content. This limitation can be circumvented by measurement of another cell cycle phase-specific cell constituent in addition to DNA content, followed by bivariate analysis of the correlated data. The aim of the present study was to explore the utility of a monoclonal antibody against the G2- and M phase-specific regulatory protein cyclin B for discrimination of cell populations with overlapping DNA content. This analysis, which was based on correlated DNA/cyclin B content measurements by flow cytometry, was applied to human lymphocytic leukemic MOLT-4 cells. The onset of cyclin B synthesis was observed in the last one third of S phase with its maximum accumulation in G2 and M phases; cells in G1 and early- and mid-S phases were negative. Cells arrested in metaphase by vinblastine expressed high levels of this protein, although not as high as in cells arrested in G2 by the DNA topoisomerase II inhibitor m-AMSA. Disruption of cytokinesis by the protein kinase inhibitor staurosporine led to DNA rereplication, cell progression through the chromatin cycle at higher DNA ploidy, and induction of polyploidy. It was possible, utilizing the cyclin B antibody, to discriminate between G2 + M cells with a 2C level of DNA and G1 cells with 4C DNA, as well as to distinguish doublets of G1 cells with a 2C DNA level. Thus, the rate of cell entrance to G1 at the 4C DNA level and the rates of progression through the cycle at both the 2C and 4C DNA levels could be simultaneously estimated. The data indicate that, in the presence of 0.1 microM staurosporine, cytokinesis of all MOLT-4 cells is impaired and the cells enter to and progress through the chromosome cycle at 4C DNA at the same rates as at 2C DNA. This approach can be helpful in the analysis of DNA ploidy and the cell cycle of human tumors when there is an overlap in DNA content values between normal stromal or infiltrating cells and aneuploid tumor cell population and may be the method of choice to investigate the activity of antitumor drugs which impair cytokinesis but do not interfere with progression of cells through the chromatin cycle.

Caffeine prevents apoptosis and cell cycle effects induced by camptothecin or topotecan in HL-60 cells

Caffeine (3,7-dihydro-1,3,7,-trimethyl-1H-purine-6,6-dione; CAF) is known to potentiate the cytotoxic effects of DNA damaging agents such as ionizing radiation and alkylating agents. In contrast, however, the cytotoxic and cytostatic activity of aromatic, DNA-intercalating, DNA topoisomerase II inhibitors such as Adriamycin, ellipticine, or mitoxantrone are diminished in the presence of CAF. To resolve whether the protective effect of CAF is associated with a particular mechanism of drug interaction (e.g., intercalation into DNA, inhibition of DNA topoisomerase II), or the aromatic nature of the drug structure, per se, we have presently studied the effects of CAF on the cytostatic and cytotoxic action of camptothecin (CAM) and its less toxic but more water soluble derivative topotecan (TPT) on HL-60 human myelogenous leukemia cells: both drugs have aromatic structures but are nonintercalating inhibitors of DNA topoisomerase I. By using spectroscopy and titration microcalorimetry, we have also studied the direct interaction between CAF and TPT in solution. Low (20 nM) concentrations of CAM or TPT perturbed progression of HL-60 cells through S-phase, whereas higher concentrations (0.15 microM) of these drugs induced apoptosis; both effects were easily demonstrable after 4 h of treatment. When added simultaneously with CAM or TPT, CAF prevented both effects. The protective effect of CAF was concentration dependent and evident within the concentration range of 1-5 mM; nearly total protection was seen at a CAF concentration of 5 mM. The bathochromic and hypochromic shift in the absorption spectrum of the water soluble compound TPT upon addition of CAF indicated that CAF and TPT interact (stack) in a fashion similar to that previously observed for CAF and DNA intercalators. Microcalorimetric measurements of TPT titration with CAF indicate an exothermic reaction between these compounds (the enthalpy change was delta H degree = -4.2 kcal/mol), which is consistent with a stacking model of CAF-TPT interaction. Thus, the ability of CAF to protect HL-60 cells against the cell kinetic effects of CAM or TPT, as in the case of DNA intercalating topoisomerase II inhibitors, is most likely due to formation of complexes between CAF and these aromatic molecules, which result in reducing the effective concentration of the free form of these drugs available to the cells.

Transfusion-associated Serratia marcescens infection: studies of the mechanism of action

The growth of two strains of Serratia marcescens in blood components was tested in this study. One of the strains had been implicated in the epidemic of transfusion-associated sepsis experienced in Denmark and Sweden in 1991. In whole blood with a final concentration of 100 colony-forming units per mL of S. marcescens, there was an immediate reduction of more than 95 percent of colony-forming units, but no reduction of the bacterial concentration if the blood had been white cell-reduced before inoculation. This is interpreted as an effect due to phagocytosis by white cells and as a lack of bactericidal effect of the plasma. A reduction to 10 percent of the original concentration, observed if the blood had a nominal content of white cells, was most likely due to phagocytosis. White cell reduction by filtration after inoculation further reduced the bacterial concentration of one of the strains tested, but, after a 1-week lag phase, growth accelerated to high concentrations by 6 weeks. In platelet-rich plasma prepared from S. marcescens-inoculated units, abundant growth was found after 24 hours, increasing to very high concentrations (10(12) colony-forming units/mL) during 10-day storage at 22 +/- 2 degrees C. Keeping the whole blood at ambient temperature for 20 hours before preparation of platelet-rich plasma caused only temporary reduction of bacterial concentration in the S. marcescens experiments, but resulted in a complete absence of bacteria in the platelet-rich plasma for 10 days in control experiments performed with Staphylococcus epidermidis.(ABSTRACT TRUNCATED AT 250 WORDS)

The cell cycle related differences in susceptibility of HL-60 cells to apoptosis induced by various antitumor agents

The studies were aimed to detect the cell cycle-associated differences in the susceptibility of HL-60 cells to apoptosis induced by diverse agents. Exponentially growing HL-60 cells were treated with the DNA topoisomerase I inhibitor camptothecin; the DNA topoisomerase II inhibitors teniposide, m-AMSA, Mitoxantrone, or Fostriecin; the presumed tyrosine kinase inhibitor genistein; a serine/threonine kinase inhibitor H7; the protein synthesis inhibitor cycloheximide; the DNA replication inhibitor hydroxyurea; the nucleoside antimetabolites 1-beta-D-arabinofuranosylcytosine and 5-azacytidine; and the alkylating agent nitrogen mustard, cisplatin, hyperthermia, and gamma irradiation. Endonucleolysis, which accompanied apoptosis induced by these agents, was assessed by two different flow cytometric methods, one based on DNA content measurements following extraction of low molecular weight DNA, and another using exogenous terminal deoxynucleotidyl transferase to label in situ DNA strand breaks. Each method allowed for both identification of apoptotic cells and analysis of the cell cycle distribution of the unaffected cell population; the method using terminal transferase also allowed for identification of the cell cycle position of apoptotic cells. Confirmed by analysis of DNA degradation by gel electrophoresis and changes in cell morphology, apoptosis was observed as early as 3 h after administration of most drugs and for some drugs was cell cycle phase specific. Cells progressing through S phase were selectively susceptible when treated with camptothecin, teniposide, m-AMSA, Mitoxantrone, H7, hydroxyurea, and 1-beta-D-arabinofuranosylcytosine. Cells in G2-M preferentially underwent apoptosis in cultures treated with H7 or with gamma-irradiation. Cells in G1 phase were preferentially affected by 5-azacytidine, nitrogen mustard, and hyperthermia. No significant cell cycle specificity was observed in the case of Fostriecin, genistein, cycloheximide, or cisplatin. The cell cycle related difference in susceptibility to apoptosis may be a reflection of both the severity of the lesion induced by a given drug and the ability of the cells to repair that lesion; both can vary depending on the cell cycle phase.

Transfusion-transmitted Yersinia enterocolitica infection. Protection through buffy coat removal and failure of the bacteria to grow in platelet-rich or platelet-poor plasma

In a previous study, removal of white blood cells (WBC), by filtration 5 h after deliberate contamination of whole blood with a type 0:3 strain of Yersinia enterocolitica, was shown to be an effective way of avoiding bacterial growth in red blood cells (RBC) during storage. In the present study the Opti-System technique was used to remove the buffy coat from whole blood, leaving 10-20% of the original number of WBC in the RBC preparation. In one series of experiments, all of 4 units of RBC suspension, from which buffy coats were removed 2 h after inoculation of 112 colony-forming units (cfu) per ml of Y. enterocolitica, became Yersinia-free, while abundant bacterial growth occurred in all of 4 units where RBC suspension and buffy coat had been recombined. In a second series of 10 experiments, with an inoculum of 80 cfu/ml, no growth was found in platelet-poor plasma stored for 42 days at 4 degrees C. Five out of 10 RBC suspensions in SAGM additive solution remained Yersinia-free throughout a 6-week storage period; 4 of these 10 units showing growth of Yersinia after 4 weeks and 5 after 6 weeks. In the buffy coats bacterial growth was found in 1 out of 10 units after 1 week, 4 after 2 weeks, and in all of 10 units after 4 weeks. In 2 control experiments with WBC-reduced RBC inoculated with the same bacterial dose, growth started within 24 h and was abundant after 1 week.(ABSTRACT TRUNCATED AT 250 WORDS)

Induction of DNA strand breaks associated with apoptosis during treatment of leukemias

A new flow cytometric method is described to detect DNA strand breaks associated with apoptosis, by labeling the 3'-OH termini in the breaks with biotinylated dUTP in a reaction employing exogenous terminal deoxynucleotidyl transferase. The method has been applied in studies on leukemic HL-60 and MOLT-4 cell lines to reveal whether it is specific to apoptotic cells, and whether it can be used in the clinic to detect DNA breakage in leukemic cells during chemotherapy. There was labeling of mononuclear cells in peripheral blood of all 11 patients studied during chemotherapy for acute lymphoblastic, acute myelogenous, or chronic myelogenous leukemia (ALL, AML, or CML) in blastic crisis, indicating induced DNA damage; the number of labeled cells increased from 1-8% before treatment up to 80% during the course of treatment. The DNA topoisomerase inhibitors mitoxantrone, VP-16 (etoposide), and m-AMSA (amsacrine) were more effective in inducing DNA breaks than was hydroxyurea or cytosine arabinoside (AraC). Cells with DNA breaks were identified in peripheral blood for up to 5 days following administration of Mitoxantrone and VP-16. In the case of DNA aneuploid leukemias, the DNA breaks were predominant in the aneuploid cell subpopulations, whereas presumably non-neoplastic diploid cells were unlabeled. In one case of ALL there were two distinct subpopulations of aneuploid cells: one responded to the treatment (by DNA breakage) and the other was non-responding. Thus, cells undergoing apoptosis can be detected by this method of labeling DNA strand breaks and the technique is applicable for analysis of response of leukemic cells to chemotherapy. With this method it may be possible to identify tumor cell sensitivity or resistance to particular drugs early in the course of treatment.

Detection of DNA strand breaks in individual apoptotic cells by the in situ terminal deoxynucleotidyl transferase and nick translation assays

DNA strand breaks which occur in HL-60 cells as a result of activation of endonuclease during apoptosis induced by cell treatment with the DNA topoisomerase I inhibitor camptothecin and topoisomerase II inhibitors teniposide, 4'-(9-acridinylamino)-3-methanesulfon-m-anisidide, and fostriecin were labeled in situ, in individual fixed and permeabilized cells, with biotinylated dUTP (detected by fluoresceinated avidin), using the terminal deoxynucleotidyl transferase or nick translation assays. During the early stage of apoptosis, prior to nuclear fragmentation, the breaks were predominantly localized at the nuclear periphery, close to the nuclear envelope. In more advanced stages, all cellular DNA, then localized within the cell as dense, homogeneous granules of a variety of sizes, was strongly labeled, indicating extensive and more uniform distribution of breaks throughout genomic DNA. Bivariate analysis of the incorporated biotinylated dUTP and cellular DNA content by flow cytometry made it possible to estimate the kinetics of the labeling reaction and relate DNA breaks to cell position in the cycle. The kinetics of biotinylated dUTP incorporation was faster, and the distinction of cells with DNA breaks was more pronounced, using the terminal transferase rather than the nick translation assay. Camptothecin, teniposide, and 4'-(9-acridinylamino)-3-methanesulfon-m-anisidide induced DNA breaks preferentially in S-phase cells, having little effect on cells in the G1 phase of the cycle. In contrast, fostriecin affected cells indiscriminately, in all phases of the cell cycle. The method of detection of DNA strand breaks (3'-hydroxyl termini) in individual cells offers several advantages and can be applied to clinical material (tumor biopsies) to study the induction of apoptosis in tumors during treatment, as a possible prognostic marker. The protein-associated DNA breaks in the "cleavable" DNA-topoisomerase complexes, which are the primary lesions induced by the inhibitors and precede apoptosis, were not detectable by the present methods.

[Alpha-adrenoceptor stimulation mediated positive chronotropic effect in isolated right heart atria of normotensive and SHRsp rats]

Concentration-dependent positive chronotropic response to phenylephrine (Phe) mediated by alpha 1-adrenoceptor in isolated normotensive and SHRsp rat right atria was determined under normal or depressed beat rate by stimulation of cholinergic M-receptor. The spontaneous beat rate was increased from 223 +/- 18 to 271 +/- 16 bpm by Phe 100 mumol.L-1 in the presence of propranolol 1 mumol.L-1. When the basal rate was lowered by stimulation of cholinergic M-receptor with carbachol, PE-induced increment of beat rate was enhanced to 101 +/- 23 bpm, accompanied by an increase of the force of contraction from 45 +/- 14% to 125 +/- 56% (vs control response). However, beta-adrenoceptor mediated positive chronotropic effect was attenuated in the presence of carbachol, and no positive inotropic effect was detected. PE-induced increase in beat rate in SHRsp (31 +/- 9 bpm) was lower than that in WKY (41 +/- 10 bpm). After pretreatment with carbachol, Phe caused increments in beat rate in SHRsp and WKY were 70 +/- 18 bpm and 114 +/- 17 bpm, respectively. It is suggested that in SHRsp, the function of cardiac alpha 1-adrenoceptor is lower than that in WKY.

Half-strength citrate CPD and new additive solutions for improved blood preservation. I. Studies of six experimental solutions

Poor stability of plasma factor VIII in whole blood and loss of erythrocyte 2,3-bis-phosphoglycerate (BPG) during red cell storage are limitations with systems for blood component preparation in current use. This study presents attempts to improve post-collection storage conditions in both these respects using half-strength citrate CPD solution (0.5CPD) for blood collection, which has been shown by others to improve the stability of factor VIII, and some compositions of hypotonic additive solutions for red cell storage containing citrate, adenine, mannitol, and phosphate. Guanosine was also included in some of the media. The erythrocyte BPG concentration was maintained at a normal level for 3-4 weeks with the best of the tested compositions. Total adenine nucleotide concentration was maintained at the original level for 49 days and adenosine triphosphate for 28 days. Spontaneous storage haemolysis was low, 0.31% (mean) +/- 0.08-0.10% (SD) after 49 days in the two best compositions. The intracellular pH was 0.2-0.3 pH units higher than the extracellular pH at the beginning of storage, but this difference gradually diminished and disappeared after 4-5 weeks. We suggest two likely explanations of the effects: the maintenance of intracellular pH at a level sufficiently high not to impair BPG synthesis until after several weeks of storage, and a sufficient supply of phosphate needed in the synthesis of organic phosphate compounds. The content of citrate was selected such that the total amount supplied to a patient in a massive transfusion, when using a combination of 0.5CPD plasma and red cell suspension, would be smaller than that provided by a transfusion of CPD whole blood.

The role of white cells in the transmission of Yersinia enterocolitica in blood components

The mechanism for the transmission of Yersinia enterocolitica in blood components has been studied experimentally. One hypothesis is that, during a Yersinia infection in the blood donor, bacteria are phagocytosed by white cells (WBCs), but are not killed. After collection of blood from such a donor and component production, the bacteria are present in WBCs for some time, during which the unit appears sterile. Later, when the WBCs disintegrate, the bacteria are released and multiply in the unit. Aliquots of whole blood and buffy coat were inoculated with 100 colony-forming units (CFU) per mL of a Y. enterocolitica strain of type O:3 and left at room temperature for 5 hours. Some aliquots were then WBC-reduced by filtration, while others retained their WBC contents. All aliquots were kept at 4 degrees C for 6 weeks. Meat extract broth culture medium was used as a control. Growth in the range of 2000 CFU per mL was obtained in the broth control by 24 hours, whereas the whole blood and buffy coat units appeared sterile for the first days of storage. After 1 week, a trace of bacteria and, after 4 weeks, massive growth were found in the WBC-containing units but not in the WBC-reduced units. The likely explanation is that the bacteria had been phagocytosed by the WBCs and were thereby hidden and not available for bacterial culture during the first phase of storage. When the WBCs spontaneously disintegrated, bacteria were released and multiplied in the blood units.(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma docosahexaenoic acid levels in various genetic forms of retinitis pigmentosa

In 188 patients from separate families with various forms of retinitis pigmentosa (RP) and 91 normal subjects, plasma fatty acids were measured as a percentage of total plasma fatty acids, and their concentrations were determined using capillary-column gas-liquid chromatography. After controlling for the effects of age and gender, those with RP had significantly lower (P less than 0.01) mean plasma percentages and concentrations of the omega-3 fatty acids: 18:3 omega 3 (alpha-linolenic acid), 22:3 omega 3 (13,16,19 docosatriaenoic acid), and 22:6 omega 3 (docosahexaenoic acid, DHA) compared with the group of normal subjects. The mean percentages were reduced 15%, 14%, and 10%, respectively, below the mean percentages in normal subjects. Analysis by genetic type revealed that the X-linked and isolate forms of RP had significantly lower (P less than 0.01) mean percentage values for DHA (18% and 17%, respectively). Dominant and recessive forms of RP had DHA levels close to normal. Mean absolute plasma DHA concentrations in X-linked RP were not significantly different from the concentrations in the control subjects, although these levels were significantly lower in patients with isolate RP. These data identify the possibility that some forms of RP may have alterations in plasma omega-3 fatty acid metabolism resulting in decreased plasma DHA content. These observations await additional confirmation using an analysis of the fatty acid content of specific erythrocyte phospholipid classes.

CT evaluation of malformed external and middle ear and its surgical correlation

This study evaluated the diagnostic value of high resolution CT (HRCT) for atresia of the external auditory meatus (EAM) and isolated middle ear malformation. CT scan of the temporal bone was done in 33 patients with such disorders and 5 patients with otosclerosis etc. were studied in the same way for comparison. Coronal HRCT clearly showed conditions of the atresia plate and malformation of the malleus, incus, abnormal course of facial canal and changes in the vestibular window. The axial HRCT is useful to demonstrate the articulations in between the malleus, incus, stapes and the cochlear window. All the HRCT findings were confirmed during operation. Axial and coronal HRCT for external and middle ear deformation is highly valuable for decision making and surgical planning.

Molecular pathogenesis of HIV-associated lymphomas

The data presented here indicate that the pathogenesis of AIDS-NHL is variably associated with multiple genetic alterations including monoclonal EBV infection, oncogene activation (c-myc, N-, Ki-ras) and tumor suppressor gene (p53) inactivation. Up to three (3 cases) or four (1 case) different lesions have been observed in the same tumor. The distribution of these lesions among the various histotypes is heterogeneous, although some preferential associations have been found either between lesion and histotype or between lesions. The most notable case involves p53 mutations/loss that is exclusively associated with the SNCC lymphoma subtype. Since alterations of the c-myc gene occur at very high frequency in this same histotype it is possible that both lesions may be required for the pathogenesis of the BL phenotype. The consistent negativity of p53 lesions in other NHLs associated or non associated with HIV infection (18) reinforces this hypothesis. Finally, we note that the frequency of p53 mutations is significantly higher in AIDS-BL than in non HIV-related BL (18), although the significancy of this difference remains to be assessed. This study confirms the relatively low frequency of EBV infection in systemic AIDS-NHL in general, but reinforces the notion that EBV may be required for the pathogenesis of AIDS-LC-IBP, as recently suggested by the high frequency of EBV positivity in primary CNS AIDS-NHL which are mostly represented by LC-IBP (2). Conversely, the low frequency of EBV sequences in the AIDS-SNCC lymphomas appears similar to that observed in sBL. Only in a small minority of cases were ras oncogene mutations found, mostly associated with the BL type.(ABSTRACT TRUNCATED AT 250 WORDS)

[24-hour esophageal pH monitoring. An analysis of 21 cases]

Esophageal pH monitoring was carried out with self-made portable pH recorder in 21 subjects for 24 hours under normal conditions. The results were as follows: the number of physiological gastroesophageal reflux (GER, pH < 4) was less than 23 times; the percentage of GER duration calculated by dividing the cumulative time of pH less than 4 by the total monitoring time was less than 1.4; the percentage was about 2 in upright position and less than 0.2 in lying position; the duration of the longest reflux episode was less than 5 minutes; the physiological gastroesophageal reflux occurred more often in upright position; while the pathological GER took place both in upright and lying position. Our study also indicated that the degree of esophagitis had no relation with the type of GER.