37 research outputs found
Assessment of ornamental fish species and fishing methods in Ibiajegbende, Lagos State, Nigeria
A study was conducted to identify ornamental fish species and fishing methods employed for the purpose of developing the fishery for international markets. Catches were sampled from 102 landings in Ibiajegbende village in Epe Local Government area of Lagos State during the fishing season that spanned from January to August 2002. Twenty-four fish species, mostly fresh water and brackish water constitute the ornamental fish species assemblage in the area. Some of these fish had seasonal appearance or dominance. Three local fishing gears and methods are employed namely Aso-oro, Iyanmo and Igu. Management strategies to upgrade the status of ornamental fishing from cottage to international level in Nigeria are discussed.
Keywords: Ornamental Fish, Ibiajegbende, and Gear AJAZEB Vol. 7 2005: pp. 23-2
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Cytokines and impaired CD8 + CTL activity among elderly persons and the enhancing effect of IL-12
We have previously demonstrated that about 70% of elderly persons exhibit deficient cytotoxic T lymphocyte (CD8
+ CTL) responses against influenza viruses when compared to young persons. Since IFN-
γ, a Th1 cytokine and IL-4, a Th2 cytokine, stimulate and inhibit CD8
+ CTL responses respectively, their role(s) in the age-related CTL deficiency was investigated. Lymphocytes from young adults (34±5 years old) and elderly subjects (71±1 years old) were stimulated in vitro with influenza A/H3N2, A/H1N1 or influenza B virus for 6–7 days. The CD8
+ CTL activity against virus-infected autologous target cells was significantly lower among the elderly than the young subjects (
P<0.01). Following stimulation with influenza virus, IL-4 production in both age groups was similar on day 3 but significantly higher among elderly persons on day 6 (
P<0.05). In contrast, T cells from the elderly produced significantly lower IFN-
γ than did those from young persons on both days (
P<0.05). Treatment of T cells from young and elderly adults with recombinant human IL-12, a pivotal cytokine that stimulates Th1 cytokines, resulted in enhancement of CD8
+ CTL activity and IFN-
γ production in a dose dependent manner (
P<0.01). IL-12-dependent enhancement of CTL activity was not always abrogated by anti-IFN-
γ antibody treatment. These results suggest that deficient influenza virus-specific CTL activity among the elderly is attributable to a Th1 to Th2 cytokine production switch. Immunotherapy with IL-12 could represent a useful approach to correct the CD8
+ CTL deficiency and cytokine imbalance among elderly humans
JC Virus-Specific Cytotoxic T Lymphocytes in Individuals with Progressive Multifocal Leukoencephalopathy
Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system caused by a reactivation of the polyomavirus JC (JCV) within a setting of immunosuppression. The nature of the immune response that contains replication of this virus is unknown. We have explored JCV-specific cellular immune responses in patients with PML and control subjects. JCV antigen-stimulated peripheral blood mononuclear cells (PBMC) of four human immunodeficiency virus (HIV)-infected patients who were survivors of PML and one HIV-uninfected patient recently diagnosed with PML lysed autologous B-lymphoblastoid cell lines expressing either the JCV T regulatory protein or the VP1 major capsid protein. This lysis was mediated by CD8(+) T lymphocytes and was major histocompatibility complex class I restricted. These cells were therefore cytotoxic T lymphocytes (CTL). JCV-specific CTL could not be detected in PBMC of three HIV-infected PML patients who had progressive neurologic disease and an eventual fatal outcome. These data suggest that the JCV-specific cellular immune response may play a crucial role in the containment of PML. This finding may also prove useful as a favorable prognostic marker in the clinical management of these patients
Role of Immunoglobulin A in Protection against Reovirus Entry into Murine Peyer's Patches
Reovirus type 1 Lang (T1L) infects the mouse intestinal mucosa by adhering specifically to epithelial M cells and exploiting M-cell transport to enter the Peyer's patches. Oral inoculation of adult mice has been shown to elicit cellular and humoral immune responses that clear the infection within 10 days. This study was designed to determine whether adult mice that have cleared a primary infection are protected against viral entry upon oral rechallenge and, if so, whether antireovirus secretory immunoglobulin A (S-IgA) is a necessary component of protection. Adult BALB/c mice that were orally inoculated on day 0 with reovirus T1L produced antiviral S-IgA in feces and IgG in serum directed primarily against the reovirus ς1 attachment protein. Eight hours after oral reovirus challenge on day 21, the Peyer's patches of previously exposed mice contained no detectable virus whereas Peyer's patches of naive controls contained up to 2,300 PFU of reovirus/mg of tissue. Orally inoculated IgA knockout (IgA(−/−)) mice cleared the initial infection as effectively as wild-type mice and produced higher levels of reovirus-specific serum IgG and secretory IgM than C57BL/6 wild-type mice. When IgA(−/−) mice were rechallenged on day 21, however, their Peyer's patches became infected. These results indicate that intestinal S-IgA is an essential component of immune protection against reovirus entry into Peyer's patch mucosa
Imogolite: An Aluminosilicate Nanotube Endowed with Low Cytotoxicity and Genotoxicity
High-aspect-ratio nanomaterials (HARN) (typically, single-walled carbon nanotubes (SWCNT) or multiwalled carbon nanotubes (MWCNT)) impair airway barrier function and are toxic to macrophages. Here, we assess the biological effects of nanotubes of imogolite (INT), a hydrated aluminosilicate [(OH)3Al2O3SiOH] occurring as single-walled NT, on murine macrophages and human airway epithelial cells. Cell viability was assessed with resazurin. RT-PCR was used to study the expression of Nos2 and Arg1, markers of classical or alternative macrophage activation, respectively, and nitrite concentration in the medium was determined to assess NO production. Epithelial barrier integrity was evaluated from the trans-epithelial electrical resistance (TEER). Potential genotoxicity of INT was assessed with comet and cytokinesis-block micronucleus cytome assays. Compared to MWCNT and SWCNT, INT caused much smaller effects on RAW264.7 and MH-S macrophage viability. The incubation of macrophages with INT at doses as high as 120 μg/cm2 for 72 h did not alter either Nos2 or Arg1 expression nor did it increase NO production, whereas IL6 was induced in RAW264.7 cells but not in MH-S cells. INT did not show any genotoxic effect in RAW264.7 and A549 cells except for a decrease in DNA integrity observed in epithelial A549 cells after treatment with the highest dose (80 μg/cm2). No significant change in permeability was recorded in Calu-3 epithelial cell monolayers exposed to INT, whereas comparable doses of both SWCNT and MWCNT lowered TEER. Thus, in spite of their fibrous nature, INT appear not to be markedly toxic for in vitro models of lung−blood barrier cell