Vaccination in Leishmaniasis: A Review Article

Leishmaniasis is caused by protozoan Leishmania parasites that are transmitted through female sandfly bites. The disease is predominantly endemic to the tropics and semi-tropics and has been reported in more than 98 countries. Due to the side effects of anti-Leishmania drugs and the emergence of drug-resistant isolates, there is currently no encouraging prospect of introducing an effective therapy for the disease. Hence, it seems that the key to disease control management is the introduction of an effective vaccine, particularly against its cutaneous form. Advances in understanding underlying immune mechanisms are feasibale using a variety of candidate antigens, including attenuated live parasites, crude antigens, pure or recombinant Leishmania proteins, Leishmania genes encoding protective proteins, as well as immune system activators from the saliva of parasite vectors. However, there is still no vaccine against different types of human leishmaniasis. In this study, we review the works conducted or being performed in this field. Key Words: Immune response, Leishmaniasis, Vaccination     

Comment on "Major Australian-Antarctic plate reorganization at Hawaiian-Emperor bend time"

Whittaker et al. (Reports, 5 October 2007, p. 83) presented reconstructions for Australia and Antarctica showing a change in relative plate motion approximately 53 million years ago, coincident with an inferred major global plate reorganization. This comment addresses problematic areas in their assumptions and the geological consequences of their reconstructions.     

Association of tcdA+/tcdB+ Clostridium difficile Genotype with Emergence of Multidrug-Resistant Strains Conferring Metronidazole Resistant Phenotype

Background:

Reduced susceptibility of Clostridium difficile to antibiotics is problematic in clinical settings. There is new evidence indicating the cotransfer of toxin-encoding genes and conjugative transposons encoding resistance to antibiotics among different C. difficile strains. To analyze this association, in the current study, we evaluated the frequency of toxigenic C. difficile among the strains with different multidrug-resistant (MDR) profiles in Iran.

Methods:

Antimicrobial susceptibility patterns and minimal inhibitory concentrations (MIC) of the isolates were determined against metronidazole, imipenem, ceftazidime, amikacin, and ciprofloxacin by agar dilution method. The association of the resistance profiles and toxigenicity of the strains were studied by PCR targeting tcdA and tcdB genes.

Results:

Among 86 characterized strains, the highest and lowest resistance rates were related to ciprofloxacin (97%) and metronidazole (5%), respectively. The frequency of resistance to other antibiotics was as follow: imipenem (48%), ceftazidime (76%), and amikacin (76.5%). Among the resistant strains, double drug resistance and MDR phenotypes were detected in the frequencies of 10.4% and 66.2%, respectively. All of the metronidazole-resistant strains belonged to tcdA ⁺/tcdB ⁺ genotype with triple or quintuple drug resistance phenotypes. MIC₅₀ and MIC₉₀ for this antibiotic was equally ≤ 8 μg/ml.

Conclusion:

These results proposed the association of tcdA ⁺/tcdB ⁺ genotype of C. difficile and the emergence of resistance strains to broad-spectrum antibiotics and metronidazole. Key Words: Multidrug resistance, Clostridium difficile, Metronidazole     

Accidental salinomycin intoxication in calves

Twenty-four 10- to 16-week-old calves in a dairy herd in Birjand, Iran, inadvertently received an excessive dose of salinomycin mixed with barley grain. There was 58% mortality within 10 d. The calves had high serum AST, LDH, and CK activities; histopathologic lesions in myocardium, liver, and kidneys; and clinical signs associated with acute and congestive heart failure.     

Influence of Biofertilizers and Phosphate Sources on the Phosphorus Uptake of Lettuce and Chemical Forms of Phosphorus in Soil

A greenhouse experiment was conducted with a factorial arrangement in a completely randomized design with three replications. Treatments consisted of two levels of plant growth promoting rhizobacteria (PGPR) (Pseudomonas fluorescens) (with and without inoculation), two levels of vermicompost (0 and 1% w/w), and four phosphate (P) sources (control, rock phosphate powder (RP), tricalcium phosphate (TCP), and triple super phosphate (SP) at 25 mg P kg^?1 level). Co-application of PGPR and RP in non-vermicompost treatments significantly increased shoot fresh weight, shoot dry matter yield, shoot P uptake, soil Ca₂-P concentration, but it significantly decreased soil Ca₈-P and Ca₁₀-P concentrations. The maximum shoot P uptake was obtained in combined application of RP with vermicompost which had no significant difference with the co-application of SP with vermicompost in bacterial and non-bacterial treatments. There was a negative correlation coefficient between shoot P concentration and chemical forms of phosphorus. It may be concluded that application of biofertilizers changed the chemical forms of inorganic phosphorus and increased P uptake by plant.     

Antibacterial finishing of cotton fabric via the chitosan/TPP self-assembled nano layers

In this study, chitosan and pentasodium tripolyphosphate (TPP)-based bilayers were fabricated on the cationized woven cotton fabrics via layer-by-layer (LBL) self-assembly technique. The initial cationic charges on cotton fabric were produced through the aminization procedure involving the covalent attachment of reactive dye to cotton fabric and subsequent reductive cleavage of the dye to free amine. Different numbers of bilayers (1, 5, and 10) consisting of chitosan/TPP have been deposited on the fabrics. The surface morphology, cationic group content, chemical surface modification, whiteness index, surface tension and antibacterial properties of the modified cotton samples were investigated using scanning electron microscopy (SEM), methylene blue test, FTIR, reflectance spectroscopy, water contact angle measurements and antibacterial test, respectively. The bacterial inhibition experiments demonstrated that the modified cotton fabric with the addition of chitosan/TPP bilayers can increase the degree of inhibition on E. coli and S. aureus bacteria. The utilized LBL method was an easy and cost-effective procedure for developing of novel antibacterial textiles with the highly attractive feature in the medical and hygienic products.     

Enhancement of viability of a probiotic Lactobacillus strain for poultry during freeze‐drying and storage using the response surface methodology

A rotatable central composite design (CCD) was used to study the effect of cryoprotectants (skim milk, sucrose and lactose) on the survival rate of a probiotic Lactobacillus strain, L. reuteri C10, for poultry, during freeze‐drying and storage. Using response surface methodology, a quadratic polynomial equation was obtained for response value by multiple regression analyses: Y = 8.59546 ? 0.01038 X₁ ? 0.09382 X₂ ? 0.07771 X₃ ? 0.054861 X₁² ? 0.04603X₃² ? 0.10938 X₁X₂. Based on the model predicted, sucrose exerted the strongest effect on the survival rate. At various combinations of cryoprotectants, the viability loss of the cells after freeze‐drying was reduced from 1.65 log colony forming units (CFU)/mL to 0.26–0.66 log CFU/mL. The estimated optimum combination for enhancing the survival rate of L. reuteri C10 was 19.5% skim milk, 1% sucrose and 9% lactose. Verification experiments confirmed the validity of the predicted model. The storage life of freeze‐dried L. reuteri C10 was markedly improved when cryoprotectants were used. At optimum combination of the cryoprotectants, the survival rates of freeze‐dried L. reuteri C10 stored at 4°C and 30°C for 6 months were 96.4% and 73.8%, respectively. Total viability loss of cells which were not protected by cryoprotectants occurred after 12 and 8 weeks of storage at 4°C and 30°C, respectively.     

Is the adapted Radimer/Cornell questionnaire valid to measure food insecurity of urban households in Tehran, Iran?

OBJECTIVE: To assess the validity of the adapted Radimer/Cornell questionnaire to measure food insecurity in low-income urban households in Tehran, the capital of Iran. DESIGN: The Radimer/Cornell questionnaire was modified and used to assess the applicability, validity and reliability of such a measure in a culturally different context of urban households in Tehran. Factor analysis and Cronbach's alpha were used to assess validity and reliability, respectively. Socio-economic characteristics and food consumption frequency of the household were used to assess the criterion validity of the questionnaire. SETTING: District 20 of Tehran. SUBJECTS: A sample of 250 Iranian nuclear households with at least one child aged 1-18 years and a non-pregnant, non-lactating woman of reproductive age, selected through a multistage random sampling method. RESULTS: Three scales, labelled as household, individual and child hunger, were extracted through factor analysis using varimax rotation. Internal consistency of the scales was 0.897, 0.820 and 0.796, respectively. Individual insecurity and child hunger were inversely correlated with monthly per capita income, father's education, mother's education and father's occupational status, and positively correlated with household size, as expected. However, household insecurity did not follow the same pattern. Consumption frequency of fruits, vegetables, dairy, red meat and rice declined as food insecurity status worsened, while bread and potato consumption increased. CONCLUSION: The results show that a modified version of the Radimer/Cornell questionnaire is a valid and reliable instrument to measure household food insecurity in a culturally different context. However, further modifications seem necessary to measure food insecurity at household level. Results lend support to the utility and applicability of experience-based measures in varying cultural communities.