Azithromycin resistance and its molecular characteristics in Neisseria gonorrhoeae isolates from a tertiary care centre in North India

Treatment guidelines for management of uncomplicated gonorrhoeae have been recently modified owing to alarming upsurge in azithromycin resistance. This study investigated the prevalence and genetic determinants of gonococcal azithromycin resistance in India. Four (5.7%) of 70 gonococcal isolates were resistant to azithromycin. Of 16 isolates investigated for molecular mechanisms of resistance, 13 (81.3%) and 6 (37.5%) isolates exhibited mutations in coding and promoter regions of mtrR gene, respectively. However, ermA, ermB and ermC genes or mutations in rrl gene were absent in all isolates. Azithromycin resistance is low in India posing no immediate threat to use of dual-therapy for syndromic management.     

The use of cadaver models to diagnose rib fractures: A pilot study

Background

In the emergency department, rib fractures are a common finding in patients who sustain chest trauma. Rib fractures may be a sign of significant, underlying pathology, especially in the elderly patients where rib fractures are associated with significant morbidity and mortality. To date, no studies have evaluated the ability of ultrasound to detect rib fractures using cadaver models and subsequently use this model as a teaching tool.

Motion‐compensated b‐tensor encoding for in vivo cardiac diffusion‐weighted imaging

Motion is a major confound in diffusion‐weighted imaging (DWI) in the body, and it is a common cause of image artefacts. The effects are particularly severe in cardiac applications, due to the nonrigid cyclical deformation of the myocardium. Spin echo‐based DWI commonly employs gradient moment‐nulling techniques to desensitise the acquisition to velocity and acceleration, ie, nulling gradient moments up to the 2nd order (M2‐nulled). However, current M2‐nulled DWI scans are limited to encode diffusion along a single direction at a time. We propose a method for designing b‐tensors of arbitrary shapes, including planar, spherical, prolate and oblate tensors, while nulling gradient moments up to the 2nd order and beyond. The design strategy comprises initialising the diffusion encoding gradients in two encoding blocks about the refocusing pulse, followed by appropriate scaling and rotation, which further enables nulling undesired effects of concomitant gradients. Proof‐of‐concept assessment of in vivo mean diffusivity (MD) was performed using linear and spherical tensor encoding (LTE and STE, respectively) in the hearts of five healthy volunteers. The results of the M2‐nulled STE showed that (a) the sequence was robust to cardiac motion, and (b) MD was higher than that acquired using standard M2‐nulled LTE, where diffusion‐weighting was applied in three orthogonal directions, which may be attributed to the presence of restricted diffusion and microscopic diffusion anisotropy. Provided adequate signal‐to‐noise ratio, STE could significantly shorten estimation of MD compared with the conventional LTE approach. Importantly, our theoretical analysis and the proposed gradient waveform design may be useful in microstructure imaging beyond diffusion tensor imaging where the effects of motion must be suppressed.     

Haemangioma of the maxillary antrum

Haemangioma of the maxillary sinus is rare. Clinical diagnosis is of utmost importance for its operative treatment and prevention of hazards. A case is reported for its rarity and some unusual features.     

The virD operon of Agrobacterium tumefaciens Ti plasmid encodes a DNA-relaxing enzyme.

The virD locus of Agrobacterium tumefaciens Ti plasmid encodes functions necessary for endonucleolytic cleavage of transferred DNA (T-DNA) prior to its transfer to plant cells. For the overproduction of the VIRD proteins in Escherichia coli a tac-virD operon fusion was constructed. A significant increase in the accumulation of VIRD proteins was observed in a lon protease-deficient E. coli host. The presence of an overlapping open reading frame (ORF) upstream of the VIRD1 coding sequence had a negative effect on VIRD1 production. A preparation containing VIRD proteins catalyzes the conversion of supercoiled (form I) DNA to relaxed (form IV) DNA. This activity is similar to that of a DNA topoisomerase. The relaxation activity lacks DNA sequence specificity, requires magnesium ion, and has no requirement for an energy source. Studies with plasmids that had lost defined DNA segments encompassing various virD coding regions showed that VIRD1 is the DNA-relaxing enzyme. In a density gradient centrifugation experiment, the DNA-relaxing activity sedimented as a 21-kDa polypeptide. Earlier studies of Jayaswal et al. [Jayaswal, R., Veluthambi, K., Gelvin, S. & Slightom, J. (1987) (J. Bacteriol. 169, 5035-5045] have shown that in E. coli VIRD2 alone is not sufficient for endonucleolytic cleavage of T-DNA and requires VIRD1 for its activity.     

Studies on Relative Toxicities of Six Insecticides on Epigeic Earthworm, Perionyx excavatus

The 96 h LC₅₀ values of six insecticides were determined on a non-target epigeic earthworm Perionyx excavatus under laboratory conditions. Cypermethrin was found most toxic to P. excavatus (LC₅₀-0.008 mg/kg), followed by endosulfan (LC₅₀-0.03 mg/kg), carbaryl (LC₅₀-6.07 mg/kg), chlorpyrifos (LC₅₀-7.3 mg/kg), aldicarb (LC₅₀-10.63 mg/kg) and monocrotophos (LC₅₀-13.04 mg/kg). When these LC₅₀ values were compared with their respective recommended agricultural doses, aldicarb and carbaryl appeared more dangerous than other pesticides because of their lower LC₅₀ values than their respective recommended agricultural dose. Mean lethal time to cause 50% mortality at recommended agricultural dose (LT₅₀) also indicated that aldicarb achieved the fastest LT₅₀ (26 h) followed by endosulfan (38 h) and carbaryl (44 h) indicating the danger of these pesticides to P. excavatus.     

Design of a bifunctional fusion protein for ovarian cancer drug delivery: single-chain anti-CA125 core-streptavidin fusion protein.

We have developed a universal ovarian cancer cell targeting vehicle that can deliver biotinylated therapeutic drugs. A single-chain antibody variable domain (scFv) that recognizes the CA125 antigen of ovarian cancer cells was fused with a core-streptavidin domain (core-streptavidin-VL-VH and VL-VH-core-streptavidin orientations) using recombinant DNA technology and then expressed in Escherichia coli using the T7 expression system. The bifunctional fusion protein (bfFp) was expressed in a shaker flask culture, extracted from the periplasmic soluble protein, and affinity purified using an IMAC column. The two distinct activities (biotin binding and anti-CA125) of the bfFp were demonstrated using ELISA, Western blot and confocal laser-scanning microscopy (CLSM). The ELISA method utilized human NIH OVCAR-3 cells along with biotinylated bovine serum albumin (B-BSA) or biotinylated liposomes, whereas, the Western blot involved probing with B-BSA. The CLSM study has shown specificity in binding to the OVCAR-3 cell-line. ELISA and Western blot studies have confirmed the bifunctional activity and specificity. In the presence of bfFp, there was enhanced binding of biotinylated antigen and liposome to OVCAR-3 cells. In contrast, the control EMT6 cells, which do not express the CA125 antigen, showed minimal binding of the bfFp. Consequently, bfFp based targeting of biotinylated therapeutic drugs, proteins, liposomes, or nanoparticles could be an alternative, convenient method to deliver effective therapy to ovarian cancer patients. Peritoneal infusion of the bfFp-therapeutic complex could also be effective in locally targeting the most common site of metastatic spread.