Bacterial infections have increased dramatically due to microbial biofilm formation resulting in chronic pathological conditions in human subjects. Microbial biofilm causes poor drug penetration and ...antibiotic resistance, which has made site‐specific sustained drug delivery the most appropriate option. Our work entails fabrication of ciprofloxacin hydrochloride (CPX) loaded nanofibers using polyvinyl alcohol (PVA) and poly(meth) methacrylate (PMMA) employing electrospinning method to form PVA:PMMA:CPX nanofibers mat. These nanofibers mat were optimized, characterized, and further subjected to anti‐biofilm activity. Microscopic images revealed average nanofibers diameter of 243 ± 80 nm with smooth surface morphology. Analytical graphs and thermal analysis confirmed drug encapsulation and drug‐polymer compatibility. In vitro studies demonstrated sustained release of CPX for 22 days displaying Hixon Crowell and two‐stage desorption kinetics. Anti‐biofilm activity showed zones of inhibition 3.0 ± 0.5 cm, 2.8 ± 0.1 cm, 2.9 ± 0.2 cm for Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, respectively which was well above the minimum inhibitory concentration levels of the bacteria forming biofilm. Conclusively, these nanofibers mat have potential to be used as an anti‐biofilm product.
We have previously reported that increased glucose levels were associated with higher serum nitric oxide (NO) levels in fructose-fed insulin resistant rats. However, the relationship between ...hyperglycemia and serum NO level was not clear. Therefore, the present study was designed to find the association between hyperglycemia and serum NO levels in Type 2 diabetic (T2DM) patients and T2DM with cardiovascular complication.
Endothelial cells (HUVEC) were treated with of D-glucose (10-100mM), and NO levels and NOS gene expression was measured. Hyperglycaemia was induced in Sprague-Dawley rats, and serum NO levels were measured after 8 weeks. For clinical evaluation, five groups of patients were recruited: Control (CT, n=48), Type 2 diabetes (T2DM, n=26), T2DM with hypertension (DMHT, n=46), Coronary artery diseases (CAD, n=29) and T2DM with coronary artery diseases (DMCD, n=38). NO (nitrite + nitrate) levels were measured from human serum.
We found a significant (p<0.05) and dose-dependent increase in NO levels in HUVEC cells after 4 hours of high glucose exposure. eNOS and iNOS gene expression was increased in HUVEC cells after different concentrations and time periods of glucose treatment. We also observed significant (149.1 ± 25 μM, p<0.01) increase in serum NO levels in hyperglycaemic rats compared to control (76.6 ± 13.2 μM). Serum NO level was significantly higher in T2DM (111.8 μM (81.7-122.4), p<0.001) and DMCD patients ((129.4 μM (121.2-143.5), p <0.001) but not in CAD patients (76.4 μM (70.5-87)), as compared to control (68.2 μM (56.4-82.3)). We found significantly lower NO levels (83.5 μM (60.5-122.9)) in subjects suffering from diabetes since more than 5 years, compared to subjects (115.3 μM (75.2-127.1), p<0.001) with less than 5 years.
In conclusion, high NO levels were observed in South Indian diabetic patients. Higher glucose levels in serum might be responsible for activation of endothelial cells to enhance NO levels.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Leishmania donovani is the causative organism of the neglected human disease known as visceral leishmaniasis which is often fatal, if left untreated. The cysteine biosynthesis pathway of Leishmania ...may serve as a potential drug target because it is different from human host and regulates downstream components of redox metabolism of the parasites; essential for their survival, pathogenicity and drug resistance. However, despite the apparent dependency of redox metabolism of cysteine biosynthesis pathway, the role of L. donovani cysteine synthase (LdCS) in drug resistance and redox homeostasis has been unexplored. Herein, we report that over-expression of LdCS in Amphotericin B (Amp B) sensitive strain (S1-OE) modulates resistance towards oxidative stress and drug pressure. We observed that antioxidant enzyme activities were up-regulated in S1-OE parasites and these parasites alleviate intracellular reactive oxygen species (ROS) efficiently by maintaining the reduced thiol pool. In contrast to S1-OE parasites, Amp B sensitive strain (S1) showed higher levels of ROS which was positively correlated with the protein carbonylation levels and negatively correlated with cell viability. Moreover, further investigations showed that LdCS over-expression also augments the ROS-primed induction of LdCS-GFP as well as endogenous LdCS and thiol pathway proteins (LdTryS, LdTryR and LdcTXN) in L. donovani parasites; which probably aids in stress tolerance and drug resistance. In addition, the expression of LdCS was found to be up-regulated in Amp B resistant isolates and during infective stationary stages of growth and consistent with these observations, our ex vivo infectivity studies confirmed that LdCS over-expression enhances the infectivity of L. donovani parasites. Our results reveal a novel crosstalk between LdCS and thiol metabolic pathway proteins and demonstrate the crucial role of LdCS in drug resistance and redox homeostasis of Leishmania.
ABSTRACT
Understanding the mechanism that allows the intracellular protozoan parasite Leishmania donovani (Ld) to respond to reactive oxygen species (ROS) is of increasing therapeutic importance ...because of the continuing resistance toward antileishmanial drugs and for determining the illusive survival strategy of these parasites. A shift in primary carbon metabolism is the fastest response to oxidative stress. A 14CO2 evolution study, expression of glucose transporters together with consumption assays, indicated a shift in metabolic flux of the parasites from glycolysis toward pentose phosphate pathway (PPP) when exposed to different oxidants in vitro/ex vivo. Changes in gene expression, protein levels, and enzyme activities all pointed to a metabolic reconfiguration of the central glucose metabolism in response to oxidants. Generation of glucose‐6‐phosphate dehydrogenase (G6PDH) (~5‐fold) and transaldolase (TAL) (~4.2‐fold) overexpressing Ld cells reaffirmed that lethal doses of ROS were counterbalanced by effective manipulation of NADPH:NADP+ ratio and stringent maintenance of reduced thiol content. The extent of protein carbonylation and accumulation of lipid peroxidized products were also found to be less in overexpressed cell lines. Interestingly, the LD50 of sodium antimony gluconate (SAG), amphotericin‐B (AmB), and miltefosine were significantly high toward overexpressing parasites. Consequently, this study illustrates that Ld strategizes a metabolic reconfiguration for replenishment of NADPH pool to encounter oxidative challenges.—Ghosh, A. K., Sardar, A. H., Mandal, A., Saini, S., Abhishek, K., Kumar, A., Purkait, B., Singh, R., Das, S., Mukhopadhyay, R., Roy, S., Das, P. Metabolic reconfiguration of the central glucose metabolism: a crucial strategy of Leishmania donovani for its survival during oxidative stress. FASEB J. 29, 2081‐2098 (2015). www.fasebj.org
Reliable, fast, and affordable diagnosis for tuberculosis (TB) remains a challenge to reduce disease incidence in resource-poor countries. Tests based on nucleotide sequences that are signature to ...Mycobacterium tuberculosis have the potential to make a positive impact on case detection rates, which can eventually help control TB. Using extensive comparative bioinformatics approach, we mined the genome for M. tuberculosis–specific genes and identified four genes so-called signature sequence (SS). With <25% homology with other known genes/proteins of mycobacterial/nonmycobacterial origin in various databases, these SS genes are ideal targets for species-specific identification. Sputum from suspected patients was liquefied using novel complete liquefying reagent, and DNA was isolated. Samples from patients (n = 417), reporting to TB clinics at two different hospitals, which met our inclusion criteria, were collected for this study. A small number (n = 143) was used for initial standardization, and the remaining patient samples (n = 274) were evaluated by SS and compared with smear microscopy, GeneXpert, culture, and clinical outcome. An overwhelming sensitivity of 97.0%, significantly higher than GeneXpert (95.0%), was seen. SS could pick all smear-negative, but culture-positive samples, along with other culture-negative samples; some of the latter were declared clinically positive. Our results yielded superior sensitivity and specificity through conventional PCR.
Silent information regulator 2 (Sir2) is involved in parasite survival and apoptosis. Here, we aimed to explore the involvement of Sir2 in amphotericin B (AmB) resistance mechanism in Leishmania ...donovani.
The expression levels of Sir2, MDR1 and NAD(+) biosynthetic pathway enzymes in AmB-resistant and -susceptible parasites were measured and total intracellular NAD(+)/NADH ratios were compared. Overexpression and knockout constructs of Sir2 were transfected in AmB-resistant and -susceptible parasites. Both resistant and susceptible parasites were inhibited with sirtinol for 4 h. The deacetylase activity of Sir2, the expression level of MDR1, the rate of AmB efflux, concentrations of reactive oxygen species (ROS) and levels of apoptosis were examined in WT, inhibited and transfected parasites, and the AmB susceptibility of the respective parasites was measured by determining the LD50 of AmB.
Levels of mRNA, protein and NAD(+)-dependent deacetylase activity of Sir2 were elevated in resistant versus susceptible parasites. Inhibition and/or deletion of Sir2 allele showed a decreased mRNA level of MDR1, lower drug efflux, increased ROS concentration, apoptosis-like phenomenon and decreased LD50 of AmB in resistant parasites. In contrast, Sir2 overexpression in susceptible parasites reversed drug susceptibility producing a resistant phenotype. This was associated with increased LD50 of AmB along with increased expression levels of MDR1, drug efflux and reduced concentrations of ROS, corresponding to decreased apoptosis of resistant to WT sensitive.
Sir2 plays a critical role in AmB resistance by regulating MDR1, ROS concentration and apoptosis-like phenomena and may be a new resistance marker for visceral leishmaniasis.
Kocuria kristinae is a gram positive coccus of the family of Micrococcacae. It inhabits the skin and mucous membranes, but it has rarely been isolated from clinical specimens and is thus considered ...to be a non-pathogenic commensal. However, it may cause opportunistic infections in patients with indwelling devices and severe underlying diseases. We are reporting an unusual case of a Kocuria kristinae urinary tract infection in a catheterized, 20-years old male. To the best of our knowledge, this is the first reported case of a catheter related urinary tract infection which was caused by Kocuria kristinae.
We aimed to estimate the household secondary infection attack rate (hSAR) of SARS‐CoV‐2 in investigations aligned with the WHO Unity Studies Household Transmission Investigations (HHTI) protocol. We ...conducted a systematic review and meta‐analysis according to PRISMA 2020 guidelines. We searched Medline, Embase, Web of Science, Scopus and medRxiv/bioRxiv for “Unity‐aligned” First Few X cases (FFX) and HHTIs published 1 December 2019 to 26 July 2021. Standardised early results were shared by WHO Unity Studies collaborators (to 1 October 2021). We used a bespoke tool to assess investigation methodological quality. Values for hSAR and 95% confidence intervals (CIs) were extracted or calculated from crude data. Heterogeneity was assessed by visually inspecting overlap of CIs on forest plots and quantified in meta‐analyses. Of 9988 records retrieved, 80 articles (64 from databases; 16 provided by Unity Studies collaborators) were retained in the systematic review; 62 were included in the primary meta‐analysis. hSAR point estimates ranged from 2% to 90% (95% prediction interval: 3%–71%; I2 = 99.7%); I2 values remained >99% in subgroup analyses, indicating high, unexplained heterogeneity and leading to a decision not to report pooled hSAR estimates. FFX and HHTI remain critical epidemiological tools for early and ongoing characterisation of novel infectious pathogens. The large, unexplained variance in hSAR estimates emphasises the need to further support standardisation in planning, conduct and analysis, and for clear and comprehensive reporting of FFX and HHTIs in time and place, to guide evidence‐based pandemic preparedness and response efforts for SARS‐CoV‐2, influenza and future novel respiratory viruses.
Digital steganography or data hiding has emerged as a new area of research in connection to the communication in secured channel as well as intellectual property protection for multimedia signals. ...The redundancy in image representation can be exploited successfully to embed specified characteristic information with a good quality of imperceptibility. The hidden multimedia information will be communicated to the authentic user through secured channel as a part of the data. This article deals with a transform domain, block-based and signal non-adaptive/adaptive technique for inserting multimedia signals into an RGB image. The robustness of the proposed method has been tested compared to the other transform domain techniques. Proposed algorithm also shows improvement in visual and statistical invisibility of the hidden information.
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