Synergistic differentiation-promoting activity of interferon gamma and tumor necrosis factor-alpha: role of receptor regulation on human neuroblasts.

Background: Interferon gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF) synergize in inducing human neuroblastoma cells to differentiate terminally in vitro into mature nonproliferating neurons. The mechanisms by which this synergistic activity takes place are still obscure.

Purpose: To understand the basis of IFN-gamma-TNF synergism, we investigated the constitutive equipment of receptors to IFN-gamma and TNF in two human neuroblastoma cell lines (i.

Cloning and comparative mapping of recently evolved human chromosome 22-specific alpha satellite DNA.

We have isolated and characterized a new alphoid probe, named p190.22. Its chromosomal location was investigated using fluorescence in situ hybridization.

Rapid stimulation of rhodamine 123 efflux from multidrug-resistant KB cells by progesterone.

Rhodamine 123 is a mitochondrial dye that is retained for prolonged periods by carcinoma cells. While investigating causes of retention of this dye, we found that 10 microM progesterone caused a rapid stimulation of efflux of rhodamine 123 within 15 min from KB V20C cells, which overexpress the multidrug resistance pump. Progesterone did not stimulate efflux from KB cells that do not overexpress the pump, and verapamil blocked rhodamine 123 efflux in the presence or absence of progesterone, indicating that rhodamine 123 is removed from KB V20C cells by the multidrug resistance pump.

Anti-HIV-1 activity and cellular pharmacology of various analogs of gossypol.

We previously reported that the racemic mixture and both enantiomers of gossypol inhibit the replication of human immunodeficiency virus-type 1 (HIV-1) (Lin et al., Antimicrob Agents Chemother 33: 2149-2151, 1989). The present study evaluates the activities of a variety of analogs of gossypol as well as a few non-gossypol analogs.

Interferon-γ-induced differentiation of human neuroblastoma cells increases cellular uptake and halflife of metaiodobenzylguanidine.

Iodine labeled metaiodobenzylguanidine (MIBG) is a radiopharmaceutical employed for both diagnosis and metabolic radiotherapy of neuroblastoma (NB). Resistance to the radiotherapeutic effects of MIBG is common, due to lack of MIBG accumulation by NB cells. MIBG enters competent cells via the noradrenaline transporter; this function requires a relative cellular maturation and is missing in most NB cell lines.

Estradiol induction of rhodamine 123 efflux and the multidrug resistance pump in rat pituitary tumor cells.

Rhodamine 123 is a fluorescent dye that localizes in mitochondria, is a substrate for the multidrug resistance pump, and is retained for long periods of time by carcinoma cells. 17 beta-Estradiol causes GH4C1 cells (rat pituitary tumor cells) to lose rhodamine 123 fluorescence faster than untreated cells. We found that estradiol induces accumulation of the mRNA for the multidrug resistance pump 3-5-fold, with maximum induction occurring within 1 day at 10(-9) M estradiol.

Interferon-gamma-induced differentiation of human neuroblastoma cells increases cellular uptake and halflife of metaiodobenzylguanidine.

Iodine labeled metaiodobenzylguanidine (MIBG) is a radiopharmaceutical employed for both diagnosis and metabolic radiotherapy of neuroblastoma (NB). Resistance to the radiotherapeutic effects of MIBG is common, due to lack of MIBG accumulation by NB cells. MIBG enters competent cells via the noradrenaline transporter; this function requires a relative cellular maturation and is missing in most NB cell lines.

Hepatitis C virus infection and mixed cryoglobulinemia: a striking association.

The high frequency of liver involvement in cryoglobulinemia is well established. Although both etiology and pathogenesis have remained so far undefined, recent studies suggest an association of mixed cryoglobulinemia with hepatitis C virus infection. To explore this hypothesis further, we assessed the prevalence of hepatitis C virus antibodies and RNA in a large group of patients, including: (1) 35 patients with cryoglobulinemia without clinical evidence of liver involvement (group 1), (2) 15 patients with symptomatic cryoglobulinemia associated with chronic liver disease (group 2) and (3) 12 patients with asymptomatic cryoglobulinemia associated with chronic liver disease (group 3).

gamma-Interferon increases metaiodobenzylguanidine incorporation and retention in human neuroblastoma cells.

Iodine-labeled m-iodobenzylguanidine (MIBG) is a widely used radiopharmaceutical for both diagnosis and biologically targeted radiotherapy of neuroblastoma. However, resistance to the radiotherapeutic effects of MIBG is often encountered, mainly due to lack of MIBG accumulation by neoplastic cells. We have investigated whether the induction of neuroblastoma cell differentiation modifies MIBG incorporation and retention.

Isolation and comparative mapping of a human chromosome 20-specific alpha-satellite DNA clone.

We have isolated and characterized a human genomic DNA clone (PZ20, locus D20Z2) that identifies, under high-stringency hybridization conditions, an alphoid DNA subset specific for chromosome 20. The specificity was determined using fluorescence in situ hybridization. Sequence analysis confirmed our previously reported data on the great similarity between the chromosome 20 and chromosome 2 alphoid subsets.

In vitro pharmacology of metaiodobenzylguanidine uptake, storage and release in human neuroblastoma cells.

Four human neuroblastoma (NB) cell lines (LAN-5, SK-N-BE(2)C, GI-LI-N, and GI-CA-N) have been investigated for their ability to take up and store [125I]metaiodobenzylguanidine (125I-MIBG) in vitro. Only SK-N-BE(2)C and LAN-5 cells were able to specifically take up MIBG, with the former cell line showing a more efficient retention of the radiotracer. 125I-MIBG incorporation in both cell lines was inhibited by norepinephrine, desipramine, ouabain and energy depletion.

5-HT2 presynaptic receptors mediate inhibition of glutamate release from cerebellar mossy fibre terminals.

'Giant' synaptosomes originating from mossy fibre terminals and having sedimentation properties different from those of standard synaptosomes were obtained from rat cerebellum. Exposure of superfused giant synaptosomes to 15 mM KCl caused the release of endogenous glutamate in a largely (about 80%) calcium-dependent manner. The K(+)-evoked overflow of glutamate was inhibited in a concentration-dependent manner by 5-hydroxytryptamine (5-HT) and by the 5-HT2 receptor agonist 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane HCl (DOI), but not by the 5-HT1A receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT).

Pefloxacin in the antibacterial treatment of immunodepressed patients.

Pefloxacin 800 to 1200 mg daily was given for 3 to 20 days, orally or intravenously, to 84 immunocompromised patients. Five patients dropped out because of side effects and 2 for other causes. Treatment efficacy was evaluated in 77 patients, 43 men and 34 women, aged 18 to 80 years.

Purification of human immunoglobulins by sequential precipitation with caprylic acid and ammonium sulphate.

We have tested the usefulness of sequential precipitation with caprylic acid and ammonium sulfate to purify human monoclonal and polyclonal immunoglobulins from sera of 11 patients with monoclonal gammapathy (4 IgG kappa, 2 IgG lambda, 2 IgM kappa, 1 IgA kappa, 2 IgA lambda), four patients with autoimmune diseases and four healthy donors. In terms of purity and activity of Ig as well as execution time and cost, this two-step non-chromatographic procedure is highly efficient for the purification of IgG, IgA and IgM, thus offering several advantages over other methods of purification. Therefore, this procedure may have useful application in the preparation of human Ig for structural studies and therapeutic purposes.

Estradiol decreases retention of rhodamine 123 fluorescence in GH4C1 pituitary tumor cells.

Rhodamine 123 is a lipophilic cationic fluorescent dye that localizes in mitochondria. We found that 17 beta-estradiol changes the ability of GH4C1 cells, clonal rat pituitary tumor cells, to retain rhodamine 123. Cells incubated with 10 micrograms/ml rhodamine 123 for 30 min at 37 C took up about equal amounts of rhodamine 123, as determined by fluorescence microscopy, regardless of whether they had been treated with estradiol.

Regulation of human squamous cell carcinoma plasma membrane associated urokinase plasminogen activator by epidermal growth factor.

The amino terminal portion of urokinase type plasminogen activator (uPA) interacts with a cell surface binding protein/receptor that recognizes a region of the molecule autonomous from that of the catalytic domain of the enzyme, which mediates the conversion of plasminogen to plasmin. The expression of cell surface uPA receptors (uPA-Rs) and their association with uPA have been implicated in cellular invasion and tissue destruction. Treatment of A431 squamous carcinoma cells (SqCC) with epidermal growth factor (EGF) has previously been shown to result in an induction of the synthesis and extracellular accumulation of uPA and the plasminogen-dependent proteolysis of extracellular matrix (ECM).

Aspartate-releasing nerve terminals in rat striatum possess D-2 dopamine receptors mediating inhibition of release.

The release of endogenous aspartic acid has been investigated using synaptosomes from rat corpus striatum. Exposure in superfusion to a depolarizing concentration of KCl (15 mM) evoked an overflow of aspartate which was almost entirely calcium-dependent. When added to the superfusion medium, dopamine (DA) and the selective DA D-2 receptor agonists quinpirole (LY-171555) and pergolide inhibited the K+ -evoked aspartate release in a concentration-dependent manner.

Induction of the differentiation of synchronized HL-60 leukemia cells by tiazofurin.

Tiazofurin is an effective inducer of the maturation of HL-60 promyelocytic leukemia cells, as monitored by increased phagocytic ability and the capacity to reduce nitroblue tetrazolium (NBT). The antimetabolite acts as a potent inhibitor of IMP dehydrogenase, which results in a profound depression in the cellular levels of guanine nucleotides. Flow cytometric analysis of DNA histograms indicated that the commitment of HL-60 cells to differentiate when exposed to tiazofurin was preceded by a transient delay in the G1 phase of the cell cycle.

A one-hour burn prevention program for grade school children: its approach and success.

A brief, one-hour program aimed at grade school children combines human moderators, a robot, and cartoons to deliver the burn prevention message. Program efficacy was demonstrated by a pretest and posttest. Performance on the posttest improved with the age of the child.

Cytotoxicity and differentiating actions of adriamycin in WEHI-3B D+ leukemia cells.

The monomyelocytic leukemia WEHI-3B D+ can be induced to differentiate into mature granulocytes in suspension culture when exposed to 40 nM adriamycin. Treated cells underwent approximately two divisions prior to reaching plateau phase, with approximately 55% of the cell population expressing nitro blue tetrazolium positivity (NBT+) by day 3. Decreased cellular proliferation was paralleled by a progressive increase in morphologically mature granulocytic cells.

Differentiation of HL-60 promyelocytic leukemia cells: simultaneous determination of phagocytic activity and cell cycle distribution by flow cytometry.

Phagocytosis of fluorescent microspheres by HL-60 promyelocytic leukemia cells following induction of differentiation with dimethyl sulfoxide (DMSO) was monitored using flow cytometry. Initiation of phagocytic capability following initiation of differentiation with 1.5% DMSO coincided with the attainment of respiratory burst activity as measured by NBT (nitro blue tetrazolium) reduction; the degree of phagocytic activity was dependent upon parameters such as microsphere size, microsphere number, and exposure time.

Differentiation of HL-60 promyelocytic leukemia cells monitored by flow cytometric measurement of nitro blue tetrazolium (NBT) reduction.

Reduction of nitro blue tetrazolium (NBT) to insoluble blue formazan granules occurs during the stimulus-induced respiratory burst of mature granulocytes and is routinely used as an indicator of the extent of granulocytic differentiation of HL-60 acute promyelocytic leukemia cells. In the present study, the differentiation of HL-60 leukemia cells induced by dimethylsulfoxide (DMSO) or retinoic acid was monitored by flow cytometric (FCM) measurement of forward and 90 degree light scatter of NBT treated cells. Two-parameter correlated analysis permitted a distinction between cells with increased forward and decreased 90 degree light scatter (NBT-), and cells with decreased forward and increased 90 degree light scatter (NBT+).