Comparison of histone variant synthesis in human lymphocytic leukemia cells and in normal lymphocytes

The synthesis of core histone variants and of histone H1 variants was determined in fresh leukemic cells of eight patients with leukemia [seven acute lymphoblastic (ALL) and one chronic lymphocytic (CLL)], in normal lymphocytes from healthy donors or from ALL patients in complete remission. Histone variant synthesis was evaluated by incubating cells with [14C]Lys and [3H]Arg in medium without Lys and Arg and then by two-dimensional polyacrylamide gel electrophoretic separations (acetic acid-urea-Triton x-100 acetic acid-urea-hexadecyltrimethylammonium bromide for core histone variants; sodium dodecyl sulfate/acetic acid-urea-hexadecyltrimethyl ammonium bromide for H1 variants). As previously reported, quiescent lymphocytes and lymphocytes stimulated with phytohaemagglutinin (PHA) showed clearcut changes in the proportions of synthesis of core histone variants and H1 variants. Leukemic lymphocytes freshly obtained from blood showed a pattern of core histone synthesis and H1 synthesis intermediate between that of quiescent and PHA-stimulated lymphocytes; this is probably due to the presence of a mixture of resting and growing cells. When leukemic cells were stimulated to grow by mitogens, the pattern of core histone and H1 variant synthesis was similar to that in mitogen-stimulated normal lymphocytes. Histone variants whose synthesis is associated with the S-phase were not synthesized in leukemic cells treated with the DNA synthesis inhibitors hydroxyurea and 1-beta-D-arabinofuranosylcytosine (Ara-C). The pattern of acetylation of histone H4 was also apparently similar in leukemic cells and normal lymphocytes. The radioactivity associated with the ubiquitinated forms of H2A increased in nongrowing lymphocytes and in leukemic cells treated with DNA synthesis inhibitors whereas they decreased after mitogenic stimulation. Variability was wide in the synthesis of ubiquitinated H2A in different cases of leukemia. The only clear-cut difference between leukemic cells and normal lymphocytes was that leukemic cells from ALL patients, but not lymphocytes from normal donors or from ALL patients in complete remission, synthesized appreciable amounts of H1 degrees, increasing after hydroxyurea/Ara-C treatment and decreasing after PHA-stimulation. In leukemic cells from a CLL patient H1 degrees synthesis was undetectable.

Histone H1(0) is synthesized by human lymphocytic leukemia cells but not by normal lymphocytes

Using a two-dimensional gel electrophoresis system (sodium dodecyl sulphate/acetic acid-urea-hexadecyltrimethylammonium bromide) coupled with fluorography, we investigated the synthesis of H1 isoproteins in leukemic cells obtained from peripheral blood of eight children suffering from acute lymphoblastic leukemia (ALL) (four T-ALL, three common ALL, and one B-ALL) and in normal peripheral lymphocytes. H1 was synthesized in leukemic cells but not in normal lymphocytes. Inhibition of DNA synthesis with hydroxyurea and 1-beta-D-arabinofuranosylcytosine induced an increase of relative synthesis of H1(0) in leukemic cells but did not induce any detectable synthesis of H1 in normal lymphocytes. H1(0) synthesis was also undetectable in peripheral lymphocytes of leukemic children in complete remission after chemotherapy and in lymphocytes of a homozygotic twin of a leukemic patient. H1(0) may be a marker of malignant transformation of lymphocytes and as such could be of use for early detection of relapse in patients with acute lymphocytic leukemia in apparent complete remission.

Correlations between embryotoxic and genotoxic effects of phenytoin in mice

The anticonvulsant drug phenytoin (DPH) has been suspected to produce embryotoxicity through an arene oxide intermediate. This drug was also found to be a genotoxic agent. These hypotheses were tested in pregnant mice modulating the phases I and II metabolizing enzymes. DPH was studied by assessing embryotoxicity, teratogenicity, and genotoxicity, the latter by the micronucleus test on the polychromatic erythrocytes of dams and fetuses. DPH embryotoxicity was potentiated by inhibiting both cytochrome P-450 and epoxide hydrase and decreased by inducing cytochrome P-450. Equivocal results were obtained by modulating cytochrome P-448. The main DPH metabolite, p-hydroxyphenytoin (HPPH), was ineffective both per se and after cytochrome induction or epoxide hydrase inhibition. DPH did not exert genotoxicity on the maternal organism, no matter which modulating agent was used. In the fetus, however, weak genotoxic effects were observed. These effects significantly increased with inhibition of epoxide hydrase; they disappeared with induction of both cytochromes P-448 and P-450 or with inhibition of the latter. No genotoxicity was exerted by HPPH, even when the enzymatic pattern was modulated. It is concluded that the major role in DPH embryotoxicity is played by the unchanged drug, while the presence of the arene oxide is determinant for genotoxic effects.

Role of interleukin-1 in the depression of liver drug metabolism by endotoxin

Endotoxin-resistant C3H/HeJ mice were used to test the hypothesis that a macrophage product, possibly interleukin-1, might mediate the depression of liver cytochrome P-450-dependent drug metabolism in endotoxin-treated mice. Depression of liver drug metabolism by endotoxin was observed in normal mice (C3H/HeN) but not in C3H/HeJ mice. Serum transfer experiments demonstrated that a serum factor was responsible for the depression of liver drug metabolism. Experiments of passive transfer of peritoneal macrophages showed that this endotoxin-induced factor might be a macrophage product. In vitro experiments showed that endotoxin-stimulated monocytes produced a factor that depressed cytochrome P-450-dependent metabolism in cultured hepatocytes. Homogeneous human monocyte and recombinant interleukin-1 also depressed liver drug metabolism both in vivo and in vitro, suggesting that this macrophage product might be involved in the regulation of liver function by the immune system.

Ia antigen expression and IL-1 activity in murine tumour-associated macrophages

Tumour-associated macrophages (TAM) isolated from five murine sarcomas had a relatively high frequency of I-A+ cells, with mean values of 27% (mFS6), 52% (MN/MCA1), 68% (N3), 62% (N4) and 98% (J3) for TAM compared to 12% for resident peritoneal macrophages. Expression of I-E in TAM was also high (29%) in the only sarcoma (N4) examined in this respect. Expression of I-A by TAM declined in culture but exposure to lymphokine supernatants maintained and increased the frequency of I-A+ cells in TAM. Transplantation of tumours into nude mice caused a marked decrease in the percentage of I-A+ TAM in the case of the N4 sarcoma (8% compared to 48%), whereas for the MN/MCA1 sarcoma the diminution was only marginal (from 53 to 41%), TAM from murine sarcomas did not constitutively release appreciable levels of interleukin-1 (IL-1) activity. Upon stimulation with bacterial lipopolysaccharides or silica, TAM showed a limited capacity to produce and release IL-1 activity compared to peritoneal macrophages. Thus the expression of I-A antigens and the IL-1-producing capacity are uncoupled in TAM from murine sarcomas. These properties of TAM could play an important role in the generation of anti-tumour immunity and/or of suppressive T-cell circuits.

Electroretinographic and visual evoked potential abnormalities in myotonic dystrophy

Pattern visual evoked potentials (VEPs) and electroretinograms (ERGs) were recorded in 20 patients with myotonic dystrophy. Thirteen out of 20 cases presented both VEP and ERG abnormalities, 3 only ERG alterations, 2 only abnormal VEPs. A significant inverse correlation between P100 latencies and b1 wave amplitude was observed, while N1-P100 and b1 wave amplitude exhibited a parallel change. These data suggest that retinal abnormalities may have a role in inducing subclinical visual pathway alterations in myotonic dystrophy.

Lymphokine production in T gamma lymphoproliferative disorders

We have studied five patients with chronic lymphocytosis consisting of large granular lymphocytes (LGL). The increased numbers of LGL in these patients had little or no natural killer activity, mediated antibody-dependent cellular cytotoxicity, and were induced to kill tumour lines after culture for 3 days with interleukin 2 (IL-2). Patients' LGL showed considerable reactivity with HNK-1 and AB8.28 monoclonal antibodies (MoAb), whereas positivity for OKM1 and N901 was found in only two subjects, and only one patient reacted with B73.1. No appreciable reactivity has been found with anti-Tac MoAb in the four patients tested. In the absence of stimulation, the patients' LGL produced no IL-2 and only minimal amounts of IL-1 and interferon (IFN). On stimulation with lipopolysaccharides (for IL-1) or phytohaemagglutinin A (PHA) (for IL-2 and IFN), they produced IL-1 and IFN in amounts similar to those produced by normal lymphocytes, but only modest levels of IL-2. These results indicated that proliferating LGL, like normal LGL, have a secretory capacity. The lack of constitutive lymphokine production, the lack of Tac receptor expression, and the defect in IL-2 production after PHA stimulation do not support the hypothesis of an autocrine proliferation sustained by a known growth factor.

Monocyte function in intravenous drug abusers with lymphadenopathy syndrome and in patients with acquired immunodeficiency syndrome: selective impairment of chemotaxis

We have investigated monocyte function in 17 intravenous drug abusers with the clinical and laboratory features of lymphadenopathy syndrome (LAS). LAS patients had normal numbers of circulating monocytes. Monocytes from LAS patients were comparable to cells from normal donors in terms of phagocytosis of latex beads, interleukin-1 secretion, O2- release and killing of antibody-sensitized lymphoma cells or actinomycin D pretreated WEHI 164 cells. In contrast 13 out of 17 LAS subjects tested in this respect as well as six out of nine AIDS patients showed a marked defect of monocyte chemotaxis. Thus monocytes from patients with LAS or AIDS have a selective defect of monocyte chemotaxis.

Production of interleukin 1 but not of procoagulant activity by large granular lymphocytes

Large granular lymphocytes (LGL) share phenotypic and functional properties with monocytes. We have investigated the production of procoagulant activity (PCA), so far attributed to cells of the monocyte-macrophage lineage, by LGL. Endotoxin triggered interleukin (IL-1) release and PCA activity by highly purified monocyte preparations. In contrast, LGL exposed to endotoxin produced IL-1 but had no PCA activity. Similarly ineffective in inducing PCA in LGL were other stimuli that either triggered monocyte PCA or stimulated the natural killer cytotoxicity of LGL. Thus, although LGL share properties with monocytes such as the capacity to produce IL-1, PCA is confined, among circulating leukocytes, to cells of the monocyte lineage.

Prostacyclin synthesis induced in vascular cells by interleukin-1

Supernatants from cultures of human monocytes that had been stimulated with endotoxin or silica induced the synthesis of prostacyclin in endothelial and smooth muscle cells. The lymphokine mediating these effects on the cells of the blood vessel wall was identified as interleukin-1; interferons and interleukin-2 were inactive. Interleukin-1-induced prostacyclin synthesis represents a new aspect of the interaction between the immune system (as well as other tissues) and the vessel wall and may serve as a basis for the development of new strategies in antithrombotic therapy.

[Amyotrophic lateral sclerosis and dementia: a rare association. Case report]

It has been reported a case of a young man with a rare syndrome: amyotrophic lateral sclerosis with dementia. The case is discussed with reference to some pathogenetic ipothesis.

Stimulation of prostacyclin synthesis in vascular cells by mononuclear cell products

Supernatants were obtained from human peripheral blood mononuclear cells stimulated with phytohemagglutinin or in a mixed lymphocyte reaction. The effect of mononuclear cell products on vascular prostacyclin (PGI2) production was measured using cultured rat aortic smooth muscle cells (SMC) or aortic rings. PGI2 was measured by radioimmunoassay of its metabolite, 6-keto-PGF1 alpha. Supernatants containing mononuclear cell products induced PGI2 production in vascular tissue. Supernatant-induced PGI2 production of SMC was relatively slow, requiring more than six hours of incubation with supernatants, and was completely prevented by aspirin, a cyclooxygenase inhibitor. The regulation of arachidonic acid metabolism by products of stimulated mononuclear cells, which is critical to the physiology and pathology of blood vessels, may be an important aspect of the interaction between immunocompetent cells and vascular tissue.

Monoclonal antibody-defined surface markers of effector cells involved in human monocyte cytotoxicity

Human adherent peripheral blood mononuclear cells were cytotoxic in vitro against the murine TU5 line in a 48-hr [3H]thymidine-release assay. Monocyte-enriched adherent cell preparations contain a small and variable (usually less than 5%) contamination with large granular lymphocytes as assessed by morphology and staining with monoclonal antibody markers B73.1 and HNK1. To assess whether killing was in fact mediated by monocytes, mononuclear cells or monocyte-enriched preparations were separated using monoclonal antibodies directed against mononuclear phagocytes (Mo2, UCHM1, B44.1) or natural killer (NK) cells (B73.1 and HNK1), and a fluorescence-activated cell sorter. Cells positive for monocyte markers were highly cytotoxic against TU5, whereas negative cells were not. B73.1+ or HNK1+ cells had little or no activity. Cytotoxicity of cells positive for monocyte markers (Mo2, UCHM1, B44.1) was augmented by in vitro exposure to lymphokines or less frequently to interferon (IFN). However, cells negative for these monocytes markers were also stimulated to kill TU5 by lymphokine or IFN to an extent similar or greater than that of positive ones. IFN or lymphokines induced killing of TU5 by monocyte-depleted, B73.1-positive, lymphoid cells. These observations demonstrate that human monocytes do kill tumor cells, either in the absence of deliberate stimulation or after exposure to agents such as lymphokines. However, the possible contribution to "monocyte" cytotoxicity of minor NK cell contaminants must be taken into account particularly when agents such as IFN and lymphokines are applied, even when a relatively NK-cell-resistant target such as TU5 is used.

A comparative study of acute toxicity of drugs used during anticancer therapy in healthy and tumor-bearing mice

A comparative study was performed, in healthy and Ehrlich ascites bearing mice, to ascertain if the acute toxicity of drugs can change in disease conditions. Adriamycin, cis-platinum, cyclophosphamide, 5-fluorouracil, vinblastine, morphine and cefoxitin were administered intravenously; prochlorperazine and acetylsalicylic acid were given orally, and dexamethasone and lonidamine were given by both routes. With the exception of morphine, the LD50's significantly decreased in tumor bearing animals. The highest potency ratios (about 4-6) were observed with prochlorperazine and cyclophosphamide and the lowest (1.3-1.4) with lonidamine given intravenously, adriamycin and acetylsalicylic acid. These results confirm that the toxic response may be strongly influenced by pathological states.

Pharmacological investigations on lonidamine

The results of a broad pharmacological screening on 1-[(2,4-dichlorophenyl)-methyl] -1H-indazole-3-carboxylic acid ( lonidamine ) a new antitumour agent which also possesses antispermatogenic and embryotoxic effects, are reported. Lonidamine does not affect general behaviour and autonomic functions and is devoid of anticonvulsant, anti-reserpine, anti-apomorphine, anti-amphetamine, antitremor , antipyretic, antiinflammatory and analgesic effects. It also lacks those side effects which are considered characteristic of different antitumour agents, such as thymus and spleen atrophy, delay in skin wound healing and damage to the gastrointestinal mucosa. At doses 40 times higher than that of hydrochlorothiazide, lonidamine produces diuretic effects. The practical importance of these findings in the current therapeutic use of lonidamine appears to be limited. The most typical signs of acute intoxication produced by high doses of lonidamine are salivation, lacrimation, diarrhea, ataxia, muscle rigidity and prostration with superimposed convulsions.

Spectroscopic study on the structure and stability of beef liver arginase

The secondary and tertiary structure of the oligomeric arginase (EC 3.5.3.1) from beef liver was investigated by circular dichroism (CD) and fluorescence measurements. The far-ultraviolet CD spectrum of the enzyme at neutral pH is indicative of high helical content. The intrinsic fluorescence emission of the protein is due to tryptophan, the contribution of tyrosine being small. Upon excitation at 295 nm, the maximum of emission occurs at 330 nm, implying that the tryptophan residues are rather buried in a hydrophobic interior of the protein. Ethylenediaminetetraacetic acid (EDTA), which inactivates the enzyme by removing the functional Mn2+-ion from the enzyme, does not dissociate the enzyme into subunits, nor affect noticeably its secondary and tertiary structure. Inactivation occurs in the acid pH range, being complete at pH below 4. However, acidification up to pH 1.5 produced only limited changes in the far-ultra-violet CD spectrum and intrinsic fluorescence emission properties. The enzyme shows noteworthy thermal stability, as shown by measuring the residual activity after heating and by evaluating the temperature dependence of the CD signal at 220 nm and the intensity of emission fluorescence. A temperature of half inactivation (Tm) of 77 degrees was determined upon heating the enzyme at pH 7.5 in the presence of Mn2+-ions for 10 min; in the presence of EDTA, Tm is shifted to 55 degrees. Taken together, these observations indicate that the structural stability of beef liver arginase arises from a clustering of hydrophobic amino acids and from Mn2+-ion binding.

[A case of retinal degeneration in a man exposed to organophosphorus pesticides]

The AA describe a case of retinal degeneration (cones and rods degeneration) which has arisen in a subject exposed to organophosphorous pesticides. The AA. discuss about the evidences of specialistic tests and point out the necessity of a particular attention to the sight apparatus in field of toxic exposures.

Hollow fiber immobilized L-asparaginase: in vivo and in vitro immunological studies

The enzyme L-asparaginase was covalently immobilized on the inner surface of the hollow fibers utilized in a commercially available dialyzer by the periodate method. After sterilization with gamma radiation the bioreactor was able to metabolize in vivo, 90 per cent of circulating asparagine in two hours. The absence in blood of asparaginase-related protein fragments, released from the hollow fiber immobilized enzyme, was monitored using a specific enzyme-linked immunosorbent assay (ELISA).