Liposome-mediated cytosolic delivery of macromolecules and its possible use in vaccine development

In the majority of bacterial and viral infections the generation of cytotoxic T cells is of particular interest because such pathogens are able to escape the host defence mechanisms by surviving intracellularly within the phagocytic cells. To generate a CD8+ T lymphocyte response against exogenous antigens, the prerequisite is their delivery into the cytosol followed by processing and presentation along with class I major histocompatibility complex (MHC-I) molecules. In the present study we describe the method of liposome-based delivery of antigens and other macromolecules into the cytosol of target cells. To develop safe and effective methods for generating CD8+ T lymphocytes, we exploited the fusogenic character of lipids derived from lower organisms, that is baker's yeast (Saccharomyces cerevisiae). The degree of fusion with model membrane systems using yeast lipid liposomes varied from 40-70%, as opposed to 1-8% observed with egg PtdCho liposomes, depending on the assay system used. The fusion of yeast lipid liposomes with macrophages resulted in effective delivery of the entrapped solutes into the cytoplasmic compartment. This was further supported by the inhibition of cellular protein synthesis in J774 A1 cells by ricin A, encapsulated in the yeast lipid liposomes. Interestingly, the model antigen ovalbumin, when entrapped in the yeast lipid liposomes, successfully elicited antigen reactive CD8+ T cell responses. It may be concluded that the liposomes made of lipids derived from S. cerevisiae can spontaneously fuse with macrophages, delivering a significant portion of their contents into the cytoplasmic compartment of the cells

An Empirical Study on the Impact of Micro-Credit Financing on the Socio-Economic Status of Small Agriculturists in Pakistan

This study empirically studies the impacts of micro-credit finance on the socio-economic status of small agriculturists in Pakistan. Little research has been conducted in this area in Pakistan. The data was gathered from 693 micro-credit finance participants and non-participants, at a 2 to 3 ratio, through an adapted questionnaire from the 8-clusters out of 12 clusters of 36 districts of Punjab using the cluster sampling technique. A survey was organized to perform the investigation in which two close-ended structured questionnaires were developed to collect data from the small agriculturists who owned less than twelve and a half acres of land. Both descriptive and inferential statistics were used to analyze the results of the study. Various statistical tests, such as EFA, SEM, KMO, ANOVA tests, etc., were used to test the expected hypothesis of the study and to confirm the affinity among variables. This research revealed that micro-credit finance has performed a positive role in developing the socio-economic status of small agriculturists after obtaining the micro-credit finance. The study indicated that micro-credit finance has played a significant role in changing and developing the socio-economic status of the respondents. Participation of small agriculturists enables the poor masses of rural areas to eradicate poverty in rural areas to enhance their living standards and to strengthen their financial conditions. The end results of the study revealed that most small agriculturists were taking benefits from micro-credit lending schemes. They also improved their socio-economic status and mitigated poverty. The findings of the study provide profound insight and should be helpful to regulators, policy makers, managers, microfinance institutions, government authorities, and all other stakeholders

Use of liposomes as an immunopotentiating delivery system: in perspective of vaccine development

Liposomes have been widely used to deliver antigens to the antigen-presenting cells (APCs) and also to modify their immunological behaviour in model animals. We recently demonstrated the potential of yeast lipid liposomes to undergo membrane-membrane fusion with cytoplasmic membrane of the target cells. Interestingly, studies in the present report revealed that antigen encapsulated in yeast lipid liposomes could be successfully delivered simultaneously into the cytosolic as well as endosomal processing pathways of APCs, leading to the generation of both CD4+ T helper and CD8+ cytotoxic T cells. In contrast, encapsulation of same antigen in egg phosphatidyl-choline (PC) liposomes, just like its free form, has inefficient access to the cytosolic pathway of major histocompatibility complex (MHC) I dependent antigen presentation and failed to generate antigen specific CD8+ cytotoxic T-cell response. However, both egg PC as well as yeast lipid liposomes have elicited strong antigen specific antibody responses in immunized animals. These results imply usage of liposome encapsulated antigen as potential candidate vaccine capable of eliciting both cell mediated as well as humoral immune responses

Undetected common variable immune deficiency in a young adult of Pakistani descent.

Common variable immune deficiency (CVID) is a syndrome which is due to deficiency of humoral immune response resulting in increased susceptibility to infections We report a case of CVID in a 24-year-old male whopresented with a history of recurrent pneumonias

Chloroquine encapsulated in malaria-infected erythrocyte-specific antibody-bearing liposomes effectively controls chloroquine-resistant Plasmodium berghei infections in mice

The suitability of liposomes as drug carriers in the treatment of drug-resistant rodent malaria was examined after covalently attaching F(ab')2 fragments of a mouse monoclonal antibody (MAb), MAb F10, raised against the host cell membranes isolated from the Plasmodium berghei-infected mouse erythrocytes, to the liposome surface. The antibody-bearing liposomes thus formed specifically recognized the P. berghei-infected mouse erythrocytes under both in vitro and in vivo conditions. No such specific binding of the liposomes with the infected cells was observed when MAb F10 was replaced by another mouse monoclonal antibody, MAb D2. Upon loading with the antimalarial drug chloroquine, the MAb F10-bearing liposomes effectively controlled not only the chloroquine-susceptible but also the chloroquine-resistant P. berghei infections in mice. The chloroquine delivered in these liposomes intravenously at a dosage of 5 mg/kg of body weight per day on days 4 and 6 postinfection completely cured the animals (75 to 90%) of chloroquine-resistant P. berghei infections. These results indicate that selective homing of chloroquine to malaria-infected erythrocytes may help to cure the chloroquine-resistant malarial infections with low doses of chloroquine

A Comparison of Sperm Motility Between Fertile and Infertile Males

Background: To determine the sperm motility of proven fertile males and compare this with that of infertile males. Methods: The study design was cross-sectional comparative and was carried out at Islamic International Medical College Rawalpindi and its attached Railway hospital and Islamabad Clinic Serving Infertile Couples Islamabad, from June 2005 to July 2006. Fifty healthy fertile males were selected and their sperm motility was determined with the latest Makler’s chamber, while another 50 infertile males were recruited as controls. The sampling technique used was convenience non-probability. Inclusion criterion for proven fertile males was pregnancy achieved within one year of marriage with successful coituses. In case of infertile males it was failure to achieve pregnancy without the use of assisted reproductive techniques, with no infertility factors in the female partner. The semen samples were obtained at the laboratory after 3 to 4 days of sexual abstinence with clear written and oral instructions given to the subjects before the collection of the sample. Results: The infertile group was found to be statistically older than the proven fertile group i.e. (36.60 versus 31.32 years). Proven fertile group showed significantly higher motility (60.32 ± 10.80%) and progressive motility (14.32 ± 8.31%) than the infertile male group. Conclusion: Sperm motility is useful in in-vivo situation to find males having a greater possibility of infertility problem. More studies with a larger sample size are required to establish a cut-off value in the local population

Why do families of sick newborns accept hospital care? a community-based cohort study in Karachi, Pakistan

Objective: Sick young infants are at high risk of mortality in developing countries, but families often decline hospital referral. Our objective was to identify the predictors of acceptance of referral for hospital care among families of severely ill newborns and infants Karachi, Pakistan. Study Design: A cohort of 541 newborns and infants referred from home by community health workers conducting household surveillance, and diagnosed with a serious illness at local community clinics between 1 January and 31 December 2007, was followed-up within 1 month of referral to the public hospital. Result: Only 24% of families accepted hospital referral. Major reasons for refusal were financial difficulties (67%) and father/elder denying permission (65%). Religious/cultural beliefs were cited by 20% of families. Referral acceptance was higher with recognition of severity of the illness by mother (odds ratio = 12.7, 95% confidence interval = 4.6 to 35.2), family\u27s ability to speak the dominant language at hospital (odds ratio = 2.0, 95% confidence interval = 1.3-3.1), presence of grunting in the infant (odds ratio = 3.3, 95% confidence interval = 1.2-9.0) and infant temperature Conclusion: Refusal of hospital referral for sick young infants is very common. Interventions that encourage appropriate care seeking, as well as community-based management of young infant illnesses when referral is not feasible are needed to improve neonatal survival in low-income countries

Numerical optimization of (FTO/ZnO/CdS/CH₃NH₃SnI₃/GaAs/Au) perovskite solar cell using solar capacitance simulator with efficiency above 23% predicted

The presented study deals with the investigations of the methyl ammonium tin halide (CH3NH3SnI3) based perovskite solar cells for optimized device performance using solar capacitance simulations software. Several necessary parameters such as metal work functions, thickness of structural layers, charge carrier’s mobility and defect density have been explored to evaluate the device performance. Calculations reveal that for the best efficiency of device the maximum thickness of the perovskite (CH3NH3SnI3) absorber layer must be 4.2 μm. The thickness values of 0.01 μm for ZnO electron transport layer (ETL), 0.871 μm for GaAs hole transport layer and 0.001 μm for CdS buffer layer have been found which proved to be optimum for maximum power conversion efficiency (PCE) of 23.80% for the device. The variation of open circuit voltage (Voc), Short circuit current (Jsc), Fill Factor (FF %), quantum efficiency (QE) against thickness of all layers and interface defect densities in FTO/ZnO/CdS/CH3NH3SnI3/GaAs/Au composition have been critically explored and their crucial role for the device performance has been reported. Heterojunctions between ZnO-ETL and CdS buffer layers have shown improved device performance and PCE. Current investigations may prove to be useful for designing and fabrication of climate friendly, non-toxic and highly efficient solar cells

Heme oxygenase-1 protects against Alzheimer’s amyloid-β1-42 induced toxicity via carbon monoxide production

Heme oxygenase-1 (HO-1), an inducible enzyme up-regulated in Alzheimer‟s disease (AD), catabolises heme to biliverdin, Fe2+ and carbon monoxide (CO). CO can protect neurones from oxidative stress-induced apoptosis by inhibiting Kv2.1 channels, which mediate cellular K+ efflux as an early step in the apoptotic cascade. Since apoptosis contributes to the neuronal loss associated with amyloid β peptide (Aβ) toxicity in AD, we investigated the protective effects of HO-1 and CO against Aβ1-42 toxicity in SH-SY5Y cells, employing cells stably transfected with empty vector or expressing the cellular prion protein, PrPc, and rat primary hippocampal neurons. Aβ1-42 (containing protofibrils) caused a concentrationdependent decrease in cell viability, attributable at least in part to induction of apoptosis, with the PrPc expressing cells showing greater susceptibility to Aβ1-42 toxicity. Pharmacological induction or genetic over-expression of HO-1 significantly ameliorated the effects of Aβ1-42. The CO-donor CORM-2 protected cells against Aβ1-42 toxicity in a concentration-dependent manner. Electrophysiological studies revealed no differences in the outward current pre- and post-Aβ1-42 treatment suggesting that K+ channel activity is unaffected in these cells. Instead, Aβ toxicity was reduced by the L-type Ca2+ channel blocker nifedipine, and by the CaMKKII inhibitor, STO-609. Aβ also activated the downstream kinase, AMP-dependent protein kinase (AMPK). CO prevented this activation of AMPK. Our findings indicate that HO-1 protects against Aβ toxicity via production of CO. Protection does not arise from inhibition of apoptosis-associated K+ efflux, but rather by inhibition of AMPK activation, which has been recently implicated in the toxic effects of Aβ. These data provide a novel, beneficial effect of CO which adds to its growing potential as a therapeutic agent