Activity and distribution of phosphoinositidase C in rat sciatic nerve.

The hydrolysis of phosphatidylinositol-4,5-bisphosphate (PIP2) by rat sciatic nerve cytosolic phosphoinositidase C [phosphoinositide-specific phospholipase C (PIC)] was studied at neutral pH and at ionic concentrations that approximate intracellular conditions. The principal water-soluble product formed was shown to be inositol trisphosphate by anion exchange chromatography. The maximum hydrolysis rate (2.5 nmol/min/mg protein) was achieved at less than 100 nM Ca2+. Hydrolysis was markedly increased to 15 nmol/min/mg protein by inclusion of K+ in the reaction mixture. In the presence of 200 mM K+, the optimum Ca2+ was increased to approximately 600 nM. Higher Ca2+ concentrations progressively inhibited PIP2 hydrolysis. Mg2+ also inhibited the reaction, but the presence of equimolar amounts of ATP and Mg2+ had no effect. Appreciable degradation of phosphatidylinositol-4-phosphate (PIP) also occurred in the nanomolar Ca2+ range, whereas breakdown of phosphatidylinositol (PI) required millimolar Ca2+. The presence of PIP but not PI inhibited PIP2 hydrolysis. Upon subcellular fractionation of nerve, more than 50% of recovered PIC activity was in the cytosol and about 20% was located in a myelin-enriched fraction. Using PIP2 as substrate, PIC activities in nerves from normal and streptozotocin-induced diabetic animals were not different. However, the myelin-associated enzyme from diabetic animals was more labile to freezing and thawing.     

Processing, assembly, and immunogenicity of human immunodeficiency virus core antigens expressed by recombinant vaccinia virus

Recombinant vaccinia viruses that contained regions of the gag-pol open reading frames of human immunodeficiency virus type 1 (HIV-1) were constructed. Cells infected with recombinants containing both gag and protease genes expressed and processed HIV gag antigens efficiently. Processing was much reduced in cells infected with recombinants containing only gag, but not the protease gene. However, significant amounts of p41 were produced by protease-defective recombinants. This protein was immunoreactive with p24-specific monoclonal antibodies and was produced in a truncated form by a recombinant containing a 3' deletion in the p15 coding region of gag ORF. These results indicate that p41 could represent an alternative gag precursor with N-terminal sequences derived from p24 and C-terminal from p15. Ultrastructural analysis of recombinant-infected cells revealed that the gag antigens expressed were assembled into retrovirus-like particles and were secreted into culture medium. This assembly process was not dependent on HIV protease function, because immature core particles were produced by recombinants lacking HIV-1 protease functions. Immunization of mice and chimpanzees with vaccinia-HIVgag recombinant viruses generated both antibody and cell-mediated immune responses to HIV gag antigens. These recombinants are therefore useful not only for studying HIV virion processing and assembly, but also for designing immunogens for the prophylaxis and immunotherapy against AIDS.     

Isolation and characterization of simian immunodeficiency viruses from two subspecies of African green monkeys

Cercopithecus aethiops (African Green monkey), a nonhuman primate species distributed throughout subsaharan Africa, has been shown to have high seroprevalence rates of antibodies to simian immunodeficiency virus (SIV), and therefore, has been proposed as a natural reservoir for immunodeficiency viruses. Our laboratories have isolated SIV-like viruses from two East African subspecies of C. aethiops designated grivet and vervet monkeys. Analysis of the structural proteins based on the molecular weights and immunologic cross-reactivity to the prototypic SIV(MAC), HIV-1, and HIV-2 isolates suggests that these viruses are distinctly different. Heterogeneity was observed in the molecular weights of the gag, pol, and env gene products between SIV isolates from vervets [SIV(AGM(VER))] and grivets [SIV(AGM(GRI))]. Phenotypically, SIV(AGM(VER)) isolates were distinguishable from SIV(AGM(GRI)) isolates by the apparent size difference of the major core antigen p24. All SIV(AGM(GRI)) and SIV(AGM(VER)) isolates were found to encode a transmembrane protein of approximately 40 kD (gp40) in contrast to gp32 of SIV(MAC). Furthermore, the transmembrane protein was shown to be encoded by the entire env open reading frame, unlike gp32 of SIC(MAC) or gp36 of SIV(AGM(TYO-1)). These data indicate that viruses from C. aethiops share common features with SIV(MAC) and HIV-1, but represent diverse SIV-like viruses which may vary according to subspecies and geographic location.     

The prognostic significance of CDKN2A homozygous deletion in IDH-mutant lower-grade glioma and glioblastoma: a systematic review of the contemporary literature

Journal of Neuro-Oncology - The most recent cIMPACT-NOW update highlighted the homozygous deletion of the Cyclin Dependent Kinase Inhibitor 2A (CDKN2A) gene as a clinically important molecular...     

Antibody-dependent enhancement of human immunodeficiency virus type 1 (HIV-1) infection in vitro by serum from HIV-1-infected and passively immunized chimpanzees.

Based on recent reports of antibody-dependent enhancement of human immunodeficiency virus type 1 (HIV-1) infection in vitro by serum from HIV-1-infected humans, sera from HIV-1 antibody-positive chimpanzees (Pan troglodytes) was evaluated for enhancing activity in an in vitro infection assay that uses MT-2 cells (a human lymphoblastoid cell line). Although fresh chimpanzee serum was found to have pronounced infection-enhancing properties in the absence of antibody to HIV-1, this effect was abolished by heat inactivation (57 degrees C, 1 hr) or treatment with cobra venom anticomplementary protein. Heat-inactivated, HIV-1 antibody-positive chimpanzee serum could enhance HIV-1 infection of MT-2 cells in vitro when combined with fresh, normal human serum. By serial serum samples from three HIV-1-infected chimpanzees, HIV-1 antibody-positive chimpanzees are shown to develop enhancing antibodies early in infection (2 mo postchallenge), whereas neutralizing antibodies develop later. Over the course of HIV-1 infection, this enhancing activity decreases while neutralizing activity increases, suggesting a possible role for enhancing and neutralizing activities in HIV-1 pathogenesis. The enhancing activity of an IgG fraction used to passively immunize chimpanzees against HIV-1 infection is shown to be present at dilutions as high as 1:65,000, offering an interesting possible reason for the failure of passive immunization to protect chimpanzees from HIV infection. These results suggest that serum from HIV-1-immunized chimpanzees might be tested to determine whether current HIV-1 candidate vaccines induce production of antibodies that mediate antibody-dependent enhancement of HIV-1 infection in this in vitro assay.     

Crisis and grace: soccer in Denmark

What is Danish in Danish football? The question marks a new horizon in the sociology of identity in an era of internationalization and Europeanization. But it also challenges us to find new methods of analyzing cultural particularity and societal relativity in body culture. Starting from differentiations between roligan (peaceful fan) vs hooligan and dyst (jousting) vs sport, the study proceeds from the class body over the configurations of space, time and product towards gender aspects and the culture of laughter, ending at the level of “frying”, mystique and grace, at the phenomenological limits of what can be sociologically rationalized in body experience and body practice. But it is not least from this level (or this intermediary space) that the questions concerning identity in movement culture arise.     

A serologic study of naturally acquired leprosy in chimpanzees

Data from longitudinally obtained serum samples spanning several years has permitted us to identify two chimpanzees with leprosy and to estimate the time of Mycobacterium leprae exposure/infection. The results confirm high levels of specific anti-M. leprae phenolic glycolipid-I (PGL-I) as well as anti-lipo-arabinomannan (anti-LAM) antibodies in both chimpanzees, and identify additional chimpanzees with possible M. leprae exposure. The observations are consistent with the hypothesis that leprosy exists in chimpanzees in the U.S.A. and suggest the possibility that M. leprae may be transmitted among chimpanzees. The data suggest that monitoring anti-PGL-I and anti-LAM IgG and IgM levels longitudinally in leprosy contacts may be useful in the recognition of preclinical leprosy.     

Nasal polyposis in a chimpanzee

A 15-year-old female chimpanzee with nasal polyposis sustained respiratory compromise when she was sedated and expired despite resuscitative efforts. Postmortem examination revealed very large fibromyxomatous nasal polyps completely obstructing the upper airway. Gross examination and histopathologic findings were indistinguishable from those of human polyps. The chimpanzee is a potential animal model for nasal polyposis that could provide basic information concerning the relationship of polyps to type I hypersensitivity and to three severe respiratory tract disorders in humans: cystic fibrosis, bronchial asthma, and the immotile cilia syndrome.     

Antimicrobial activity of clavines

The antimicrobial activity of two clavine-type ergot alkaloids (agroclavine, festuclavine), and 16 derivatives against four human pathogenic bacteria and Candida albicans was determined. It is shown that all ergolines tested with one exception exhibit antibacterial properties against one to four bacteria species. The most active compounds are 6-allyl-6-norfestuclavine (minimal inhibitory concentration (MIC) 30 micrograms/ml against Staphylococcus aureus), 1-propyl-6-norfestuclavine (MIC 60 micrograms/ml against Escherichia coli), 6-cyano-6-norfestuclavine (MIC 250 micrograms/ml against Pseudomonas aeruginosa), and 1-methyl-agroclavine (MIC 200 micrograms/ml against Proteus vulgaris). 1-Allyl-6-norfestuclavine and 1-propyl-6-norfestuclavine showed a broad action spectrum: the growth of all four bacteria species and of Candida albicans was inhibited. The most effective antifungal compounds are 1-propyl-6-norfestuclavine and 6-cyano-6-norfestuclavine (MIC 250 micrograms/ml). Three alkaloids of different structure (codeine, emetine, quinine) are inactive up to 500 micrograms/ml against the bacteria species and C. albicans. The acute toxicity (mouse) is remarkably diminished by the modifications of the natural clavines.     

Clavines. New antibiotics with cytostatic activity

The cytostatic potentials of ten ergolines were determined in the L5178y mouse lymphoma cell system; six of them belong to the clavines (agroclavine, 1-propyl-agroclavine, 1-propyl-festuclavine, 1-allyl-festuclavine, 6-cyano-6-nor-festuclavine and 1-hydroxymethyl-festuclavine) and four to the lysergic acid derivatives (methylergometrine, lysergic acid amide, isolysergic acid amide and lysergic acid diethylamide). It is shown that agroclavine (ED50: 3.9 microM), 1-propyl-agroclavine (3.5 microM), 1-propylfestuclavine (4.3 microM) and 1-allyl-festuclavine (4.3 microM) are potent cytostatic agents. Up to 2 X ED50 concentration the inhibitory effect was completely reversible. Incorporation studies suggested that the compounds inhibit DNA synthesis; this assumption was also supported by the findings which revealed that after incubation with these clavines, the cells showed slight 'unbalanced growth'. 6-Cyano-6-nor-festuclavine was less inhibitory (ED50 11.8 microM). 1-Hydroxymethyl-festuclavine and all lysergic acid derivatives tested were without any detectable activity.