Bivek Timalsina

Microcystin-LR (MC-LR) is one of a large family of cyanotoxins which are naturally produced by cyanobacteria within harmful algal blooms occurring in bodies of water globally. Early findings of the toxicity of such blooms stemmed from fatalities of livestock drinking from affected water. Since then, various toxins have been identified such as the microcystins. Microcystin-LR has been studied as a representative congener due to its abundance and toxicity. While there have been extensive studies of microcystin-LR by oral route exposure, we have turned our attention to inhalation route exposure due to the recent findings of microcystin-containing lake and sea-spray aerosol. We have shown inflammatory outcomes in the airways of mice and in human cell culture models after microcystin aerosol exposure, and have found a consistent molecular patterns similar to those of Type 1/Type 17 driven neutrophilic asthma. Here we address the hypothesis that MC-LR will increase the inflammatory mediators of neutrophilic asthma leading to worsening symptoms. This is tested and characterized in both in vitro and in vivo models. We found that asthma symptoms and molecular signatures of inflammation are both worsened by MC-LR exposure in a mouse model of neutrophilic asthma. We found that 3D human airway cell culture models reconstructed from asthmatic donor cells are similarly affected, however healthy donor cells are nearly unaltered by comparison. Aggregating these findings with RNA sequencing data from all models, we developed a hypothetical molecular mechanism which relies on MC-LR mediated amplification of existing inflammatory signaling. We test this in a human reporter cell line of NF-κB activity and further demonstrate the mechanism by inhibitor testing. This study sheds light on the risk to asthmatic patients living near or recreating on affected bodies of water. Beyond asthma, we believe this study provides crucial insight into the findings over the last 40 years concerning disparate outcomes of MC-LR exposure as the result of exposure will be dependent on the signaling state of the tissue upon exposure.

Commonly used adenine-induced chronic kidney disease (CKD) murine models often employ C57BL/6 mice; however, this strain has inherent limitations due to its natural resistance to developing key pathological features of CKD, such as tubulointerstitial fibrosis and inflammation. There have been attempts to overcome these barriers by using multiple concentrations of adenine-supplemented diets or by performing prolonged experiments up to 20 weeks. Here, we demonstrate that SKH1 Elite mice develop clinically relevant CKD phenotypes (e.g., polyuria, proteinuria, inflammation, and renal fibrosis) over the course of only 6 weeks of low-dose (0.15%) adenine supplementation. As a docile, immunocompetent, and hairless strain, SKH1 Elite mice offer several logistical advantages over C57BL/6 mice, including ease of handling and the ability to study dermal conditions, which are often secondary to CKD.

Harmful algal blooms are increasing globally and pose serious health concerns releasing cyanotoxins. Microcystin-LR (MC-LR), one of the most frequently produced cyanotoxins, has recently been detected in aerosols generated by the normal motions of affected bodies of water. MC-LR aerosol exposure has been linked to a pro-inflammatory influence on the airways of mice; however, little is understood about the underlying mechanism or the potential consequences. This study aimed to investigate the pro-inflammatory effects of aerosolized MC-LR on murine airways. C57BL/6 and BALB/c mice were exposed to MC-LR aerosols, as these strains are predisposed to type 1/type 17 and type 2 immune responses, respectively. Exposure to MC-LR induced granulocytic inflammation in C57BL/6 but not BALB/c mice, as observed by increased expression of cytokines MIP-1α, CXCL1, CCL2, and GM-CSF compared with their respective vehicle controls. Furthermore, the upregulation of interleukins IL-17A and IL-12 is consistent with Th1- and Th17-driven type 1/type 17 inflammation. Histological analysis confirmed inflammation in the C57BL/6 lungs, with elevated neutrophils and macrophages in the bronchoalveolar lavage fluid and increased pro-inflammatory and pro-resolving oxidized lipids. In contrast, BALB/c mice showed no significant airway inflammation. These results highlight the ability of aerosolized MC-LR to trigger harmful airway inflammation, requiring further research, particularly into populations with predispositions to type 1/type 17 inflammation.

Harmful algal blooms are increasing globally and pose serious health concerns releasing cyanotoxins. Microcystin-LR (MC-LR), one of the most frequently produced cyanotoxins, has recently been detected in aerosols generated by the normal motions of affected bodies of water. MC-LR aerosol exposure has been linked to a pro-inflammatory influence on the airways of mice, however little is understood about the underlying mechanism or the potential consequences. This study aimed to investigate the pro-inflammatory effects of aerosolized MC-LR on murine airways. C57BL/6 and BALB/c mice were exposed to MC-LR aerosols, as these strains are predisposed to type 1/type 17 and type 2 immune responses, respectively. Exposure to MC-LR induced granulocytic inflammation in C57BL/6 but not BALB/c mice, as observed by increased expression of cytokines MIP-1α, CXCL1, CCL2, and GM-CSF compared with their respective vehicle controls. Furthermore, the upregulation of interleukins IL-17A and IL-12 is consistent with Th1 and Th17 driven type 1/type 17 inflammation. Histological analysis confirmed inflammation in the C57BL/6 lungs, with elevated neutrophils and macrophages in the bronchoalveolar lavage fluid and increased pro-inflammatory oxidized lipids. In contrast, BALB/c mice showed no significant airway inflammation. These results highlight the ability of aerosolized MC-LR to trigger harmful airway inflammation, requiring further research.

Translation: The University of Toledo Journal of Medical Sciences is the online journal launched by the University of Toledo. Manuscripts will be considered on the understanding that they report original work and are not under consideration for publication by any other journal. The journal publishes original articles reporting experimental results of basic or clinical research, case reports, and reviews. The journal uses a single blind peer review system and each manuscript, based on the results presented in its original submission, will be evaluated by two student reviewers and one faculty reviewer. This process will provide an opportunity for medical students, graduate students, residents, fellows and faculty to publish research observation in a timely manner.

Translation: The University of Toledo Journal of Medical Sciences is the online journal launched by the University of Toledo. Manuscripts will be considered on the understanding that they report original work and are not under consideration for publication by any other journal. The journal publishes original articles reporting experimental results of basic or clinical research, case reports, and reviews. The journal uses a single blind peer review system and each manuscript, based on the results presented in its original submission, will be evaluated by two student reviewers and one faculty reviewer. This process will provide an opportunity for medical students, graduate students, residents, fellows and faculty to publish research observation in a timely manner.

Aim: Resistance to methicillin and Macrolide–Lincosamide and Streptogramins B and their association with erm genes in Staphylococcus aureus are unknown in Nepal. Materials & methods: Nonduplicate n... Lay abstract With the increased prevalence of methicillin-resistant S. aureus in hospital- and community-acquired infections, there has been an upsurge in resistance toward Macrolide–Lincosamide–St...

Antibiotic resistance exhibited by Staphylococcus aureus is a growing global concern. This work was undertaken to determine the prevalence rate of inducible clindamycin resistant S. aureus in nasal sample and detect ermB gene in the isolates with inducible clindamycin resistance. Nasal swabs were collected from the school children and cultured on Mannitol Salt Agar (MSA) and Blood Agar (BA) for observation of colony morphology. Gram staining and biochemical test (catalase, oxidase, O-F and coagulase) were performed for further identification of the bacteria. The Kirby-Bauer disc diffusion method using a cefoxitin disc (30 μg) was used to detect methicillin resistant S. aureus (MRSA). All, the MRSA isolates were tested for ermB gene by PCR amplification. Among 64 S. aureus isolates, 17 (26 %) were MRSA. The prevalence of Inducible clindamycin resistant S. aureus (iMLSB) isolates was 23.4 % in the S. aureus isolates. All the isolates of MRSA were resistant to penicillin, while 88.2 % were sensitive to gentamicin. The prevalence of ermB gene was 3.1 % in the total S. aureus isolates and 11.7 % MRSA showed the presence of this gene. Routinely performing a D-test in laboratory will guide the clinicians on the rationale use of clindamycin and improving hygienic practices can reduce the spread of inducible clindamycin resistance.

Antiretroviral therapy has led to a profound improvement in the clinical care of HIV-infected patients. However, drug tolerability and the evolution of drug resistance have limited treatment options for many patients. Maturation inhibitors are a new class of antiretroviral agents for treatment of HIV-1. They act by interfering with the maturation of the virus by blocking the last step in Gag processing: the cleavage of the capsid-spacer peptide 1 (CA-SP1) intermediate to mature CA by the viral protease (PR). The first-in-class maturation inhibitor bevirimat (BVM) failed against a subset of HIV-1 isolates in clinical trials due to polymorphisms present in the CA-SP1 region of the Gag protein. Sequence analysis indicated that these polymorphisms are more common in non-clade B strains of HIV-1 such as HIV-1 clade C. Indeed, BVM was found to be ineffective against HIV-1 clade C molecular clones tested in this study. A number of BVM analogs were synthesized by chemical modifications at the C-28 position to improve its activity. The new BVM analogs displayed potent activity against HIV-1 clade B and C and also reduced infectivity of the virus. This study identifies novel and broadly active BVM analogs that may ultimately demonstrate efficacy in the clinic.

Introduction: Tuberculosis remains a worldwide public health problem despite the highly effective drugs and vaccines are available making tuberculosis a preventable and curable disease. The objective of this study was to compare the different laboratory diagnostic methods of tuberculosis and determine its prevalence. Methodology: Morning sputum samples were collected from suspected cases of pulmonary tuberculosis and preceded for Ziehl Neelsen staining, fluorescent staining (auramin-O) and mycobacterium culture in Lowenstein Jensen medium. Results: Total 78 suspected cases of pulmonary tuberculosis were included in this study among them 53 were male and 25 were female. Out of 78 cases, 46 cases were found to be culture positive. In culture positive cases (83%) were found to be M. tuberculosis and (17%) were found to be slow grower, fine colonies, AFB positive but niacin test negative (mycobacteria other than M. tuberculosis). In the direct microscopic examination by Ziehl Neelsen stained smear 26 samples were found to be acid fast bacilli and one sample was culture negative but acid fast bacilli positive. In fluorescent stained smear 34 samples were found to be positive for acid fast bacilli and 5 samples were culture negative but acid fast bacilli positive. Culture was accepted as gold standard, the sensitivity of direct microscopic examination was found 56.5% for Ziehl Neelsen staining and 73.9% for fluorescent staining respectively. Conclusion: In culture positive cases M. tuberculosis and mycobacteria other than M. tuberculosis was found to be 83% and 17% respectively, it was found higher in male than female. Fluorescent microscopy is superior to Ziehl Neelsen microscopy but gives more false positive result than Z-N staining. Combining of Ziehl Neelsen and fluorescent staining is better than fluorescent staining alone.DOI: http://dx.doi.org/10.3126/saarctb.v11i2.12427 SAARC J TUBER LUNG DIS HIV/AIDS, 2014;XI(2), page: 1-6