A nationwide investigation was carried out to determine the current susceptibility status of Culex quinquefasciatus Say populations against four active ingredients representing four major insecticide classes: DDT, propoxur, malathion, and permethrin. Across 14 study sites, both larval and adult bioassays exhibited dissimilar trends in susceptibility. A correlation between propoxur and malathion resistance and between propoxur and permethrin resistance in larval bioassays was found. The results obtained from this study provide baseline information for vector control programs conducted by local authorities. The susceptibility status of this mosquito should be monitored from time to time to ensure the effectiveness of current vector control operations in Malaysia.
House dust mites and storage mites are well-known causes for allergenic diseases. The aim of this study was to investigate the immunogenic sites of Blomia tropicalis, Aleurogyphus ovatus and Glycycometus malaysiensis. The mites were maintained in a culture medium at 25ºC and 75% relative humidity. Mites were harvested either with heat escape or floatation method, purified, homogenized, quantified and used for the production of polyclonal antibody and immunostaining. For each species of mites, five male mice and five male rats were randomly selected and immunized intraperitoneally with respective crude mite extract at two-weekly intervals. Blomia tropicalis, A. ovatus or G. malaysiensis whole mites and paraffin-embedded mite sections were immunostained with the respective polyclonal antibody. The faecal pellets of mites were intensely stained for all the three species in the present study. The legs of sectioned A. ovatus were not immunogenic as compared with those of G. malaysiensis and B. tropicalis. The outer layer (cuticle) of whole mites and the eggs for these species were very immunogenic. Hence, the polyclonal antibodies obtained in this study may serve as potential tools in detecting the eggs and immature mites in environmental samples. Future studies should focus on the antigenic components of eggs since they were relatively abundant in dust and highly antigenic as seen in the present study.
Potential tumor imaging radiopharmaceutical agents have been prepared by attaching a cisplatin derivative to a ligand capable of forming a stable complex with 99mTc. Three new organometallic compounds, with iminodiacetic acid as the 99mTc chelating group and 2,3-diaminopropionamide as the platinum complexing group, have been prepared and characterized. Preliminary biodistribution studies in tumor bearing mice support the utility of this approach.
Different murine species differ in their susceptibility to systemic infection with Candida albicans, giving rise to varied host immune responses, and this is compounded by variations in virulence of the different yeast strains used. Hence, this study was aimed at elucidating the pathogenesis of a clinical C. albicans isolate (HVS6360) in a murine intravenous challenge model by examining the different parameters which included the counts of red blood cells and associated components as well as the organ-specific expression profiles of cytokines and chemokines. Kidneys and brains of infected mice have higher fungal recovery rates as compared to other organs and there were extensive yeast infiltration with moderate to severe inflammation seen in kidney and brain tissues. Red blood cells (RBCs) and haemoglobin (Hb) counts were reduced throughout the infection period. Pattern recognition receptors (PRRs), chemokines and cytokine transcription profiles were varied among the different organs (kidney, spleen and brain) over 72 h post infections. Transcription of most of the PRRs, cytokines and chemokines were suppressed at 72 h post infection in spleen while continuous expression of PRRs, cytokines and chemokines genes were seen in brain and kidney. Reduction in red blood cells and haemoglobin counts might be associated with the action of extracellular haemolysin enzyme and haeme oxygenase of C. albicans in conjunction with iron scavenging for the fungal growth. Renal cells responsible for erythropoietin production may be injured by the infection and hence the combined effect of haemolysis plus lack of erythropoietin-induced RBC replenishment leads to aggravated reduction in RBC numbers. The varied local host immune profiles among target organs during systemic C. albicans infection could be of importance for future work in designing targeted immunotherapy through immunomodulatory approaches.
Dengue virus (DENV) has emerged as a major economic concern in developing countries, with 2.5 billion people believed to be at risk. Vascular endothelial cells (ECs) lining the circulatory system from heart to end vessels perform crucial functions in the human body, by aiding gas exchange in lungs, gaseous, nutritional and its waste exchange in all tissues, including the blood brain barrier, filtration of fluid in the glomeruli, neutrophil recruitment, hormone trafficking, as well as maintenance of blood vessel tone and hemostasis. These functions can be deregulated during DENV infection. In this study, BALB/c mice infected with DENV serotype 2 were analyzed histologically for changes in major blood vessels in response to DENV infection. In the uninfected mouse model, blood vessels showed normal architecture with intact endothelial monolayer, tunica media, and tunica adventitia. In the infected mouse model, DENV distorted the endothelium lining and disturbed the smooth muscle, elastic laminae and their supporting tissues causing vascular structural disarrangement. This may explain the severe pathological illness in DENV-infected individuals. The overall DENV-induced damages on the endothelial and it's supporting tissues and the dysregulated immune reactions initiated by the host were discussed.
Breast cancer is the most commonly diagnosed cancer and the leading cause of cancer death among females globally. The tumorigenic activities of cancer cells such as aldehyde dehydrogenase (ALDH) activity and differentiation have contributed to relapse and eventual mortality in breast cancer. Thus, current drug discovery research is focused on targeting breast cancer cells with ALDH activity and their capacity to form secondary tumors. Citral (3,7-dimethyl-2,6-octadienal), from lemon grass (Cymbopogoncitrates), has been previously reported to have a cytotoxic effect on breast cancer cells. Hence, this study was conducted to evaluate the in vivo effect of citral in targeting ALDH activity of breast cancer cells. BALB/c mice were challenged with 4T1 breast cancer cells followed by daily oral feeding of 50 mg/kg citral or distilled water for two weeks. The population of ALDH+ tumor cells and their capacity to form secondary tumors in both untreated and citral treated 4T1 challenged mice were assessed by Aldefluor assay and tumor growth upon cell reimplantation in normal mice, respectively. Citral treatment reduced the size and number of cells with ALDH+ activity of the tumors in 4T1-challenged BALB/c mice. Moreover, citral-treated mice were also observed with smaller tumor size and delayed tumorigenicity after reimplantation of the primary tumor cells into normal mice. These findings support the antitumor effect of citral in targeting ALDH+ cells and tumor recurrence in breast cancer cells.
The intraspecific variation of four laboratory-reared isolates of Taenia taeniaformis the SRN and KRN isolates from Norway rats, Rattus norvegicus, captured in Japan and Malaysia, respectively; the BMM isolated from a house mouse, Mus musculus, captured in Belgium; and the ACR isolate from a gray red-backed vole, Clethrionomys rufocanus bedfordiae, captured in Japan was examined by various criteria. Eggs of each of the four isolates were orally inoculated into several species of intermediate host. They were most infective to the rodent species from which the original metacestode of each isolate had been isolated in the field, and only the ACR isolate was infective to the gray red-backed vole. Although little difference was found between the SRN, KRN, and BMM isolates by the other criteria, including the morphology of rostellar hooks, the protein composition of the metacestode, and restriction endonuclease analysis of DNA, the ACR isolate was clearly different from the others. It was considered that the ACR isolate was independent as a strain distinct from the other three isolates.
Burkholderia pseudomallei is the causative agent of melioidosis. We initiated this investigation with a virulent and an attenuated strain of B. pseudomallei. Pulsed-field gel electrophoresis was carried out initially for macrogenomic comparison of both strains of B. pseudomallei. However, the pulsotypes obtained were identical and therefore we applied a subtractive hybridization technique to distinguish and determine the possible differences between the two strains. Six virulence strain-specific DNA fragments were obtained and the encoding homolog proteins were identified as a xenobiotic-responsive element family of transcriptional regulator, a hypothetical protein, an unknown protein, a plasmid recombination enzyme, a regulatory protein and a putative hemolysin activator protein. A combination of at least three of these determinants was identified in 45 clinical isolates when screening was carried out with self-designed multiplex PCR targeting the six putative virulent determinants. Our data demonstrated that different combinations of the six putative virulence genes were present in the clinical isolates indicating their probable role in the pathogenesis of B. pseudomallei infections.
Newcastle disease virus (NDV) is a member of the Paramyxoviridae that has caused severe economic losses in poultry industry worldwide. Several strains of NDV were reported to induce cytolysis to cancerous cell lines. It has prompted much interest as anticancer agent because it can replicate up to 10,000 times better in human cancer cells than in most normal cells. In this study, two NDV strains, viserotropic-velogenic strain AF2240 and lentogenic strain V4-UPM, showed cytolytic activity and apoptosis induction against Mouse myelomoncytic leukemia (WEHI 3B). The cytolytic effects of NDV strains were determined using microtetrazolium (MTT) assay. The cytolytic dose - fifty percent (CD(50)) were 2 and 8HAU for AF2240 and V4-UPM strains, respectively. Cells treated with NDV strains showed apoptotic features compared to the untreated cells under fluorescence microscope. NDV induced activation of caspase-3 and DNA laddering in agarose gel electrophoresis which confirmed the apoptosis. The anti-leukemic activity of both strains was evaluated on myelomoncytic leukemia BALB/c mice. The results indicated that both NDV strains significantly decreased liver and spleen weights. It also decreased blasts cell percentage in blood, bone marrow and spleen smears of treated mice (p<0.05). Histopathological studies for spleen and liver confirmed the hematological results of blood and bone marrow. From the results obtained, the exposure to both NDV stains AF2240 and V4-UPM showed similar results for Ara-c. In conclusion NDV strains AF2240 and V4-UPM can affect WEHI 3B leukemia cells in vitro and in vivo.
Plant phenolics are important nutritional antioxidants which could aid in overcoming chronic diseases such as cardiovascular disease and cancer, two leading causes of death in the world. The oil palm (Elaeis guineensis) is a rich source of water-soluble phenolics which have high antioxidant activities. This study aimed to identify the in vivo effects and molecular mechanisms involved in the biological activities of oil palm phenolics (OPP) during healthy states via microarray gene expression profiling, using mice supplemented with a normal diet as biological models.
Toxoplasma gondii is an intra-cellular parasite that infects humans through vertical and horizontal transmission. The cysts remain dormant in the brain of infected humans and can reactivate in immunocompromised hosts resulting in acute toxoplasmic encephalitis which may be fatal. We determined the onset and progression of brain cysts generation in a mouse model following acute toxoplasmosis as well as the ability of brain cysts to reactivate in vitro. Male Balb/c mice, (uninfected control group, n = 10) were infected orally (study group, n = 50) with 1000 tachyzoites of T. gondii (ME49 strain) and euthanized at 1, 2, 4, 8 and 16 weeks post infection. Brain tissue was harvested, homogenized, stained and the number of brain cysts counted. Aliquots of brain homogenate with cysts were cultured in vitro with confluent Vero cells and the number of cysts and tachyzoites counted after 1 week. Brain cysts but not tachyzoites were detected at week 2 post infection and reached a plateau by week 4. In vitro Vero cells culture showed similar pattern for cysts and tachyzoites and reactivation of cyst in vitro was not influenced by the age of the brain cysts.
Bacterial secreted proteins are known to be involved in virulence and may mediate important host-pathogen interactions. In this study, when the stationary phase culture supernatant of Burkholderia pseudomallei was subjected to 2-DE, 113 protein spots were detected. Fifty-four of the secreted proteins, which included metabolic enzymes, transcription/translation regulators, potential virulence factors, chaperones, transport regulators, and hypothetical proteins, were identified using MS and database search. Twelve of these proteins were apparently reactive to antisera of mice that were immunised with B. pseudomallei secreted proteins. These proteins might be excellent candidates to be used as diagnostic markers or putative candidate vaccines against B. pseudomallei infections.
Congenitally T and B cell-deficient SCID mice and T cell-deficient NUDE mice, with BALB/c mice as immunologically normal controls, were inoculated with Rhinosporidium seeberi. At 3 and 16 weeks after inoculation, no evidence of rhinosporidiosis was detected. The reasons for the failure to establish rhinosporidiosis in immunodeficient or normal mice remain obscure.
A cytotoxic T lymphocyte (CTL) response to dengue virus-infected target cells is described. Effector cells were generated in an in vitro secondary culture and appeared to be T cells possessing both the Lyt 1.1 and Lyt 2.1 surface antigens. A stronger CTL response was noted with the H-2k haplotype compared to H-2d, and H-2 compatibility was required between CTL and target cells. CTL generated showed some cross-reactivity with target cells infected with Japanese encephalitis virus (JEV), another flavivirus, but not with target cells infected with an alphavirus, Sindbis. The significance and importance of these findings are discussed.
Nipah virus and Hendra virus are closely related and following natural or experimental exposure induce similar clinical disease. In humans, encephalitis is the most serious outcome of infection and, hitherto, research into the pathogenesis of henipavirus encephalitis has been limited by the lack of a suitable model. Recently we reported a wild-type mouse model of Hendra virus (HeV) encephalitis that should facilitate detailed investigations of its neuropathogenesis, including mechanisms of disease recrudescence. In this study we investigated the possibility of developing a similar model of Nipah virus encephalitis.
Mung bean has been traditionally used to alleviate heat stress. This effect may be contributed by the presence of flavonoids and γ-aminobutyric acid (GABA). On the other hand, fermentation and germination have been practised to enhance the nutritional and antioxidant properties of certain food products. The main focus of current study was to compare the antistress effect of none-process, fermented and germinated mung bean extracts. Acute and chronic restraint stresses were observed to promote the elevation of serum biochemical markers including cholesterol, triglyceride, total protein, liver enzymes, and glucose. Chronic cold restraint stress was observed to increase the adrenal gland weight, brain 5-hydroxytryptamine (5-HT), and malondialdehyde (MDA) level while reducing brain antioxidant enzyme level. However, these parameters were found reverted in mice treated with diazepam, high concentration of fermented mung bean and high concentration of germinated mung bean. Moreover, enhanced level of antioxidant on the chronic stress mice was observed in fermented and germinated mung bean treated groups. In comparison between germinated and fermented mung bean, fermented mung bean always showed better antistress and antioxidant effects throughout this study.