Ancient machinery embedded in the contemporary ribosome.

Structural analysis, supported by biochemical, mutagenesis and computational evidence, indicates that the peptidyltransferase centre of the contemporary ribosome is a universal symmetrical pocket composed solely of rRNA. This pocket seems to be a relic of the proto-ribosome, an ancient ribozyme, which was a dimeric RNA assembly formed from self-folded RNA chains of identical, similar or different sequences. This could have occurred spontaneously by gene duplication or gene fusion.

Induction of apoptosis by ultrasound application in human malignant lymphoid cells: role of mitochondria-caspase pathway activation.

In the present study, we have focused on the specific question of whether ultrasound application (ULS) delivered with optimized parameters for cavitation generation can stimulate apoptosis in lymphoid cell lines. Suspended T and B lymphoid cell lines (Jurkat and Raji, respectively) were exposed to low frequency ULS (750 KHz) at an intensity level of 54.6 W/cm(2) spatial peak temporal average (SPTA) at focal area, which was found to be the optimal physical parameter to induce apoptosis in these malignant cell lines.

Apoptosis induction of human myeloid leukemic cells by ultrasound exposure.

Therapeutic ultrasound (ULS) and the resulting cavitation process has been shown to induce irreversible cell damage. In this study, we wanted to further investigate the mechanism of ULS-induced cell death and to determine whether apoptosis is involved. High intensity focused pulsed ULS sonication at a frequency of 750 KHz was delivered to HL-60, K562, U937, and M1/2 leukemia cell line cultures.

Adhesion molecules involved in the interactions between early T cells and mesenchymal bone marrow stromal cells.

We previously reported that among the various thymic lymphocyte subpopulations, the immature T cells preferentially adhere to mesenchymal bone marrow stroma. In the present study we examined the interactions between phenotypically defined populations of early T cells and stromal cell lines. The immature T cells segregated into two subpopulations according to their adhesive capacity.

Ultrasound inhibits the adhesion and migration of smooth muscle cells in vitro.

This study investigated in vitro the effect of therapeutic ultrasound (ULS) on smooth muscle cell (SMC) function as adhesion, migration and proliferation. Experiments were conducted on aortic SMC in culture. The LD50 was established (1.

Adhesion of thymocytes to bone marrow stromal cells: regulation by bFGF and IFN-gamma.

We recently reported on selective interactions between immature T cell subpopulations and bone marrow (BM) stromal cells. To further study this process, we first examined the efficacy of methods estimating cell-cell adhesion and then investigating the effects of cytokines on thymocyte-stroma associations. Techniques based on the use of the fluorochromes calcein-acetomethylester (calcein-AM) and fluorescein diacetate (FDA) were studied and compared to regular cell counting methods.

Selective adhesion of immature thymocytes to bone marrow stromal cells: relevance to T cell lymphopoiesis.

We investigated the interactions between the bone marrow microenvironment and T cell populations at different stages of maturation. Thymocytes were seeded onto confluent layers of bone marrow stromal cell lines (MBA-13 or 14F1.1).

Safety of coronary ultrasound angioplasty: effects of sonication on intact canine coronary arteries.

The purpose of this work was to examine in vivo the safety of sonication in the coronary arteries in a live animal model. In intact dogs (n = 8), balloon dilatation was performed on the proximal left anterior descending artery (LAD) followed by sonication to the left circumflex artery (LCX) in power levels found to be optimal for thrombus ablation. Post-dilatation and post-ultrasound coronary angiography, echocardiography, histopathology, CK-MB, indices of hemolysis, and coagulation were compared.

Streptokinase immunogenicity in thrombolytic therapy for acute myocardial infarction.

The major drawback in implementing thrombolytic therapy with streptokinase in cases of acute myocardial infarction (AMI) stems from its antigenicity. To evaluate the dimensions of this problem, the immune response following thrombolytic therapy with streptokinase was prospectively studied in 16 patients with AMI. Streptokinase was given to 12 patients once and to 4 patients twice within 4-14 days.

Comparison of the Bactec and lysis concentration methods for recovery of Brucella species from clinical specimens.

In a comparison of the Bactec system and the lysis concentration procedure in the isolation of Brucella species in 54 patients the recovery rate was similar (60% and 55%, respectively). However, the recovery time was significantly shorter with the lysis concentration method than with the Bactec system (3.5 days versus 14 days).

Ultrasonic angioplasty in totally occluded peripheral arteries. Initial clinical, histological, and angiographic results.

Background: Ultrasonic angioplasty was recently shown to ablate thrombi and atherosclerotic plaques in vitro and to recanalize occluded arteries in experimental animal models. The goal of the present study was to examine the clinical feasibility of ultrasonic angioplasty.

Methods And Results: Intraoperative ultrasonic angioplasty was performed in vivo on totally occluded peripheral arteries (n = 7).

Immunologic effects of AS101 in the treatment of cancer patients.

AS101 [ammonium trichloro(O,O'-dioxyethylene)tellurate] is a new immunomodulator previously shown to stimulate the production of different cytokines in vitro and in vivo. We report here our results of a phase I clinical trial conducted on 47 cancer patients with advanced malignancies. AS101 was administered intravenously at escalating doses from 1 to 10 mg/m2, twice or thrice a week.

Stimulation of human T cell colony growth by a lymphocyte colony enhancement factor derived from lymphocyte subpopulations.

Blood mononuclear cells (MNC) develop into T cell colonies when the cells are sensitized with PHA and seeded in a two-layer soft agar system. Conditioned medium (CM) derived from MNC enhanced lymphocyte colony formation when it was added to the culture system. CFU-TL appear to be stimulated into colony formation by molecules secreted by lymphocyte subpopulations contained in the seeded cells.

Characterization of the interference of T cell activation by reserpine.

It has been suggested that reserpine blocks expression of delayed hypersensitivity (DH) reactions by depleting tissue mast cells of serotonin, thereby preventing a T cell-dependent release of mast cell serotonin necessary to localize and to amplify the DH response. However, reserpine blocks expression of DH in mast cell-deficient mice. Recently, we showed that the ability of reserpine to interfere with the expression of contact sensitivity was independent of an effect on mast cells, but reflected an effort of the drug on effector T cell function.

A new model of autoimmune disease. Experimental autoimmune uveoretinitis induced in mice with two different retinal antigens.

Experimental autoimmune uveoretinitis (EAU) is an organ-specific, T lymphocyte-mediated autoimmune disease, which serves as a model for several human ocular inflammations of an apparently autoimmune nature. EAU pathology in some rodents and in monkeys can readily be induced by immunization with several different retinal proteins; however, advancing research into the cellular mechanisms of this disease has raised the need for an EAU model in an immunologically and genetically well defined species. We report here the induction of EAU in the mouse, which has hitherto been considered a species refractory to EAU, with two retinal Ag, the retinal soluble Ag and the interphotoreceptor retinoid-binding protein.

Thymus-derived stromal cell lines.

We derived stromal cell lines from mouse thymus using methods previously established for bone marrow stroma. Two main morphologically distinct groups of cell strains emerged: epithelioid and mixed fibroblast-macrophage. Transmission electron microscopy revealed frequent junctional-complex formations between adjacent cells, a feature that characterized almost all of the thymus stromal lines, but was confined to only one of the five distinct subtypes of cell lines from bone marrow.

Human muscle-derived, tissue specific, myocytotoxic T cell lines in dermatomyositis.

Mononuclear cells were isolated from the inflamed muscle tissue of a patient suffering from dermatomyositis (DM). These were expanded in long-term culture and maintained in the presence of IL-2 containing culture medium. Two cell lines were established, one of the helper/inducer (OKT4+) and the other of the suppressor/cytotoxic phenotype (OKT8+).

Induction of experimental autoimmune uveoretinitis by T-cell lines.

Experimental autoimmune uveoretinitis was induced in genetically susceptible Lewis rats by passive transfer of T-lymphocyte cell lines from long-term cultures primed against soluble retinal antigen (S-Ag). A continuous T-cell line was established from non-adherent lymph node cells of S-Ag-immunized Lewis rats. The lymphoid cells were propagated in vitro by serially restimulating them with S-Ag in the presence of irradiated syngeneic spleen cells and expanding them in IL-2-containing media.

Identification and purification of human T-lymphocyte colony-enhancing factor, TLCEF: increased production by phorbol myristate acetate.

T-lymphocyte colony-enhancing factor (TLCEF), a growth factor for a minute subpopulation of T lymphocytes, is produced, along with other factors, by conditioned media (CM) of mononuclear cells following stimulation with T mitogens, such as phytohaemagglutinin (PHA). A combination of PHA and a co-mitogen, phorbol 12-myristate 13-acetate (PMA), has been shown to have a synergistic effect on the production of TLCEF, yielding levels of activity eight to fifteen times higher than those obtained with either PHA or PMA alone. TLCEF was purified by ammonium sulphate, fractionation hydrophobic interaction chromatography on phenyl-Sepharose and gel filtration.

Monoclonal antibodies to Müller's cells of the retina.

The immunohistologic properties of two monoclonal antibodies produced by hybridomas generated from bovine retinal S-antigen (S-Ag) immunized mice were investigated. These monoclonal antibodies demonstrated a low antibody titer to the original S-Ag preparation by the ELISA method. Immunohistologic studies using avidin-biotin-peroxidase complex (ABC) showed strong specific binding to the retinal Müller cells of all species tested (human, bovine, guinea pig and rat), a weaker binding to cell bodies and proximal component of the outer segments of the photoreceptor, but no apparent binding to the distal component of the outer segments of the photoreceptor cells.

Regulation of human B-cell colony growth.

PHA-induced B-cell enriched populations from venous blood of healthy adults developed into B-cell colonies. Analyses of individual colonies revealed that 80-85% of the cells in each colony were surface membrane immunoglobulin positive. Most colonies, 84%, contained surface IgM-bearing cells.