Determination of total phenol, condensed tannin and flavonoid contents and antioxidant activity of Uncaria gambirextracts

Uncaria  gambir,  a  well  known  Southeast  Asia  plant  have  been  previously used as an alternative medicine for treatment such as diarrheal, sore throat and spongy  gums.  Due  to  its  useful  properties,  in  this  study  we  have  analysed  the total  phenol,  condensed  tannin,  flavonoid  content  and  antioxidant  activity  of Uncaria  gambir in  three  different  solvent  extracts.  Characterization  and quantification analysis using Fourier Transform Infrared (FTIR) spectroscopy and reverse  phase-high  performance  liquid  chromatography  (RP-HPLC)  has confirmed  that  the  major  chemical  constituents  of  Uncaria  gambir are  mainly catechins.  It  was  revealed  that  the  ethyl  acetate  gambir  extract  gives  the highest  catechin  content  and  antioxidant  activity  compared  with  other  solvent extracts.Key words: Uncaria gambir, antioxidant activity, condensed tannin, flavonoid

Microencapsulated islet allografts in diabetic NOD mice and nonhuman primates

OBJECTIVE: Our goal was to assess the efficacy of encapsulated allogeneic islets transplanted in diabetic NOD mice and streptozotocin (STZ)-diabetic nonhuman primates (NHPs).MATERIALS AND METHODS: Murine or NHP islets were microencapsulated and transplanted in non-immunosuppressed mice or NHPs given clinically-acceptable immunosuppressive regimens, respectively. Two NHPs were treated with autologous mesenchymal stem cells (MSCs) and peri-transplant oxygen therapy. Different transplant sites (intraperitoneal [i.p.], omental pouch, omental surface, and bursa omentalis) were tested in separate NHPs. Graft function was monitored by exogenous insulin requirements, fasting blood glucose levels, glucose tolerance tests, percent hemoglobin A1c (% HbA1c), and C-peptide levels. In vitro assessment of grafts included histology, immunohistochemistry, and viability staining; host immune responses were characterized by flow cytometry and cytokine/chemokine multiplex ELISAS.RESULTS: Microencapsulated islet allografts functioned long-term i.p. in diabetic NOD mice without immunosuppression, but for a relatively short time in immunosuppressed NHPs. In the NHPs, encapsulated allo-islets initially reduced hyperglycemia, decreased exogenous insulin requirements, elevated C-peptide levels, and lowered % HbA1c in plasma, but graft function diminished with time, regardless of transplant site. At necropsy, microcapsules were intact and non-fibrotic, but many islets exhibited volume loss, central necrosis and endogenous markers of hypoxia. Animals receiving supplemental oxygen and autologous MSCs showed improved graft function for a longer post-transplant period. In diabetic NHPs and mice, cell-free microcapsules did not elicit a fibrotic response.CONCLUSIONS: The evidence suggested that hypoxia was a major factor for damage to encapsulated islets in vivo. To achieve long-term function, new approaches must be developed to increase the oxygen supply to microencapsulated islets and/or identify donor insulin-secreting cells which can tolerate hypoxia.</p

Test site predicts HIV care linkage and antiretroviral therapy initiation: a prospective 3.5 year cohort study of HIV-positive testers in northern Tanzania

Abstract Background Linkage to HIV care is crucial to the success of antiretroviral therapy (ART) programs worldwide, loss to follow up at all stages of the care continuum is frequent, and long-term prospective studies of care linkage are currently lacking. Methods Consecutive clients who tested HIV-positive were enrolled from four HIV testing centers (1 health facility and 3 community-based centers) in the Kilimanjaro region of Tanzania as part of the larger Coping with HIV/AIDS in Tanzania (CHAT) prospective observational study. Biannual interviews were conducted over 3.5 years, assessing care linkage, retention, and mental health. Bivariable and multivariate logistic regression analyses were conducted to determine associations with early death (prior to the second follow up interview) and delayed (>6 months post-test) or failed care linkage. Results A total of 263 participants were enrolled between November, 2008 and August, 2009 and 240 participants not already linked to care were retained in the final dataset. By 6 months after enrollment, 169 (70.4 %) of 240 participants had presented to an HIV care and treatment facility; 41 (17.1 %) delayed more than 6 months, 15 (6.3 %) died, and 15 (6.3 %) were lost to follow up. Twenty-six patients died before their second follow up visit and were analyzed in the early death group (10.8 %). Just 15 (9.6 %) of those linked to care had started ART within 6 months, but 123 (89.1 %) of patients documented to be ART eligible by local guidelines had started ART by the end of 3.5 years. On multivariate analysis, male gender (OR 1.72; 95 % CI 1.08, 2.75), testing due to illness (OR 1.63; 95 % CI 1.01, 2.63), and higher mean depression scale scores (4 % increased risk per increase in depression score; 95 % CI 1 %, 8 %) were associated with early death. Testing at a community versus a hospital-based site (OR 2.89; 95 % CI 1.79, 4.66) was strongly associated with delaying or never entering care. Conclusions Nearly 30 % of the cohort did not have timely care linkage, ART initiation was frequently delayed, and testing at a hospital outpatient department versus community-based testing centers was strongly associated with successful care linkage

Test Site Predicts HIV Care Linkage and Antiretroviral Therapy Initiation: A Prospective 3.5 Year Cohort Study of Hivpositive Testers in Northern Tanzania

Background: Linkage to HIV care is crucial to the success of antiretroviral therapy (ART) programs worldwide, loss to follow up at all stages of the care continuum is frequent, and long-term prospective studies of care linkage are currently lacking. Methods: Consecutive clients who tested HIV-positive were enrolled from four HIV testing centers (1 health facility and 3 community-based centers) in the Kilimanjaro region of Tanzania as part of the larger Coping with HIV/AIDS in Tanzania (CHAT) prospective observational study. Biannual interviews were conducted over 3.5 years, assessing care linkage, retention, and mental health. Bivariable and multivariate logistic regression analyses were conducted to determine associations with early death (prior to the second follow up interview) and delayed (\u3e6 months post-test) or failed care linkage. Results: A total of 263 participants were enrolled between November, 2008 and August, 2009 and 240 participants not already linked to care were retained in the final dataset. By 6 months after enrollment, 169 (70.4 %) of 240 participants had presented to an HIV care and treatment facility; 41 (17.1 %) delayed more than 6 months, 15 (6.3 %) died, and 15 (6.3 %) were lost to follow up. Twenty-six patients died before their second follow up visit and were analyzed in the early death group (10.8 %). Just 15 (9.6 %) of those linked to care had started ART within 6 months, but 123 (89.1 %) of patients documented to be ART eligible by local guidelines had started ART by the end of 3.5 years. On multivariate analysis, male gender (OR 1.72; 95 % CI 1.08, 2.75), testing due to illness (OR 1.63; 95 % CI 1.01, 2.63), and higher mean depression scale scores (4 % increased risk per increase in depression score; 95 % CI 1 %, 8 %) were associated with early death. Testing at a community versus a hospital-based site (OR 2.89; 95 % CI 1.79, 4.66) was strongly associated with delaying or never entering care. Conclusions: Nearly 30 % of the cohort did not have timely care linkage, ART initiation was frequently delayed, and testing at a hospital outpatient department versus community-based testing centers was strongly associated with successful care linkage

The Use of Biomaterials in Islet Transplantation

Pancreatic islet transplantation is a therapeutic option to replace destroyed β cells in autoimmune diabetes. Islets are transplanted into the liver via the portal vein; however, inflammation, the required immunosuppression, and lack of vasculature decrease early islet viability and function. Therefore, the use of accessory therapy and biomaterials to protect islets and improve islet function has definite therapeutic potential. Here we review the application of niche accessory cells and factors, as well as the use of biomaterials as carriers or capsules, for pancreatic islet transplantation

Listeriolysin O Is Strongly Immunogenic Independently of Its Cytotoxic Activity

The presentation of microbial protein antigens by Major Histocompatibility Complex (MHC) molecules is essential for the development of acquired immunity to infections. However, most biochemical studies of antigen processing and presentation deal with a few relatively inert non-microbial model antigens. The bacterial pore-forming toxin listeriolysin O (LLO) is paradoxical in that it is cytotoxic at nanomolar concentrations as well as being the source of dominant CD4 and CD8 T cell epitopes following infection with Listeria monocytogenes. Here, we examined the relationship of LLO toxicity to its antigenicity and immunogenicity. LLO offered to antigen presenting cells (APC) as a soluble protein, was presented to CD4 T cells at picomolar to femtomolar concentrations- doses 3000–7000-fold lower than free peptide. This presentation required a dose of LLO below the cytotoxic level. Mutations of two key tryptophan residues reduced LLO toxicity by 10–100-fold but had no effect on its presentation to CD4 T cells. Thus there was a clear dissociation between the cytotoxic properties of LLO and its very high antigenicity. Presentation of LLO to CD8 T cells was not as robust as that seen in CD4 T cells, but still occurred in the nanomolar range. APC rapidly bound and internalized LLO, then disrupted endosomal compartments within 4 hours of treatment, allowing endosomal contents to access the cytosol. LLO was also immunogenic after in vivo administration into mice. Our results demonstrate the strength of LLO as an immunogen to both CD4 and CD8 T cells

Protective Immunity to Listeria Monocytogenes Infection Mediated by Recombinant Listeria innocua Harboring the VGC Locus

In this study we propose a novel bacterial vaccine strategy where non-pathogenic bacteria are complemented with traits desirable for the induction of protective immunity. To illustrate the proof of principle of this novel vaccination strategy, we use the model organism of intracellular immunity Listeria. We introduced a, low copy number BAC-plasmid harbouring the virulence gene cluster (vgc) of L. monocytogenes (Lm) into the non-pathogenic L. innocua (L.inn) strain and examined for its ability to induce protective cellular immunity. The resulting strain (L.inn::vgc) was attenuated for virulence in vivo and showed a strongly reduced host detrimental inflammatory response compared to Lm. Like Lm, L.inn::vgc induced the production of Type I Interferon's and protection was mediated by Listeria-specific CD8+ T cells. Rational vaccine design whereby avirulent strains are equipped with the capabilities to induce protection but lack detrimental inflammatory effects offer great promise towards future studies using non-pathogenic bacteria as vectors for vaccination

Listeria pathogenesis and molecular virulence determinants

The gram-positive bacterium Listeria monocytogenes is the causative agent of listeriosis, a highly fatal opportunistic foodborne infection. Pregnant women, neonates, the elderly, and debilitated or immunocompromised patients in general are predominantly affected, although the disease can also develop in normal individuals. Clinical manifestations of invasive listeriosis are usually severe and include abortion, sepsis, and meningoencephalitis. Listeriosis can also manifest as a febrile gastroenteritis syndrome. In addition to humans, L. monocytogenes affects many vertebrate species, including birds. Listeria ivanovii, a second pathogenic species of the genus, is specific for ruminants. Our current view of the pathophysiology of listeriosis derives largely from studies with the mouse infection model. Pathogenic listeriae enter the host primarily through the intestine. The liver is thought to be their first target organ after intestinal translocation. In the liver, listeriae actively multiply until the infection is controlled by a cell-mediated immune response. This initial, subclinical step of listeriosis is thought to be common due to the frequent presence of pathogenic L. monocytogenes in food. In normal indivuals, the continual exposure to listerial antigens probably contributes to the maintenance of anti-Listeria memory T cells. However, in debilitated and immunocompromised patients, the unrestricted proliferation of listeriae in the liver may result in prolonged low-level bacteremia, leading to invasion of the preferred secondary target organs (the brain and the gravid uterus) and to overt clinical disease. L. monocytogenes and L. ivanovii are facultative intracellular parasites able to survive in macrophages and to invade a variety of normally nonphagocytic cells, such as epithelial cells, hepatocytes, and endothelial cells. In all these cell types, pathogenic listeriae go through an intracellular life cycle involving early escape from the phagocytic vacuole, rapid intracytoplasmic multiplication, bacterially induced actin-based motility, and direct spread to neighboring cells, in which they reinitiate the cycle. In this way, listeriae disseminate in host tissues sheltered from the humoral arm of the immune system. Over the last 15 years, a number of virulence factors involved in key steps of this intracellular life cycle have been identified. This review describes in detail the molecular determinants of Listeria virulence and their mechanism of action and summarizes the current knowledge on the pathophysiology of listeriosis and the cell biology and host cell responses to Listeria infection. This article provides an updated perspective of the development of our understanding of Listeria pathogenesis from the first molecular genetic analyses of virulence mechanisms reported in 1985 until the start of the genomic era of Listeria research