Diagnosis of Mycobacterial infections (Tuberculosis and Paratuberculosis) in tissue samples using molecular (inhouse multiplex PCR, PCR and TaqMan real-time PCR), histopathology and immunohistochemical techniques

An in-house multiplex PCR designed for differential detection of M. bovis, M. avium paratuberculosis (MAP) and M. smegmatis in tissue samples, besides PCR and TaqMan real-time PCR targeting esxA (ESAT-6) and esxB (CFP-10) gene of M. tuberculosis complex (MTC) and IS900 gene targeting MAP were carried out in the present study. Tissue samples comprising of lung, mediastinal lymph node, intestine and mesenteric lymph node from cattle and buffaloes (n=16) suspected to have died of tuberculosis (TB) or paratuberculosis (JD) were collected at post-mortem. Out of 16 animals, only 4 (25%) cases were positive for M. bovis by in-house designed multiplex PCR, where as 9 (56.25%) cases were positive for MTC by both conventional and real-time PCR targeting esxA (ESAT-6) and esxB (CFP-10) genes. Out of 9 TB positive animals, 2 (22.22%) had co-infection with MAP as confirmed by IS900 PCR, real-time PCR and also by in-house multiplex PCR. No samples were found positive for M. smegmatis by the in-house multiplex PCR. Analytical sensitivity of in-house multiplex primers targeting M. bovis, MAP and M. smegmatis were 170 fg/µl, 300 fg/µl and 51 fg/µl of genomic DNA respectively. Analytical sensitivity of primers for both conventional and real time PCR tareting esxA were 8 pg/µl and 800 fg/µl, esxB were 800 fg/µl and 80 fg/µl and IS900 were 30 fg/µl and 3 fg/µl of M. tuberculosis and MAP genomic DNA respectively. The tissue samples were also subjected to histopathology and Immunohistochemical (IHC) staining using ESAT-6 and CFP-10 antibodies for TB and anti-JD anti-serum (raised in rabbit) for JD. All the animals positive for TB (9 of 9) and JD (2 of 2) in PCR and real-time PCR were also positive in histopathology and IHC. Thus, combination of molecular, histopathology and IHC techniques increased the accuracy of TB and JD diagnosis, all of which had same sensitivity and specificity except the in-house multiplex PCR which was comparatively less sensitive in M. bovis detection. However, the molecular methods were found to be more convenient and rapid, capable of making the diagnosis within 6 hours. The study indicated that Real-time PCR was ten times more sensitive than the conventional PCR.

Biomacromolecule immobilization: grafting of fish-scale collagen peptides onto aminolyzed P(3HB-co-4HB) scaffolds as a potential wound dressing

Polyhydroxyalkanoate (PHA) is a microbial polymer that has been at the forefront of many attempts at tissue engineering. However, the surface of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P(3HB-co-4HB)) is hydrophobic with few recognition sites for cell attachment. Various concentrations of fish-scale collagen peptides (FSCPs) were incorporated into P(3HB-co-4HB) copolymer by aminolysis. Later, FSCPs were introduced onto the aminolyzed P(3HB-co-4HB) scaffolds. Introduction of the FSCP groups was verified using Fourier transform infrared spectroscopy and the ninhydrin method. The effect of the incorporation of FSCPs on hydrophilicity was investigated using the water contact angle. As the concentration of FSCPs increased, the water contact angle decreased. In vitro study demonstrated that P(3HB-co-4HB)/FSCP scaffolds provided better cell attachment and growth of L929 mouse fibroblast cells and better cell proliferation. In vivo study showed that P(3HB-co-4HB)/1.5 wt% FSCPs had a significant effect on wound contractions, with the highest percentage of wound closure (61%) in 7 d.

Basic concepts for sample size calculation: Critical step for any clinical trials!

Quality of clinical trials has improved steadily over last two decades, but certain areas in trial methodology still require special attention like in sample size calculation. The sample size is one of the basic steps in planning any clinical trial and any negligence in its calculation may lead to rejection of true findings and false results may get approval. Although statisticians play a major role in sample size estimation basic knowledge regarding sample size calculation is very sparse among most of the anesthesiologists related to research including under trainee doctors. In this review, we will discuss how important sample size calculation is for research studies and the effects of underestimation or overestimation of sample size on project's results. We have highlighted the basic concepts regarding various parameters needed to calculate the sample size along with examples.

Phylogenetic analysis of VP2 gene of canine parvovirus and comparison with Indian and world isolates

Canine parvovirus (CPV) causes hemorrhagic enteritis, especially in young dogs, leading to high morbidity and mortality. It has four main antigenic types CPV-2, CPV-2a, CPV-2b and CPV-2c. Virus protein 2 (VP2) is the main capsid protein and mutations affecting VP2 gene are responsible for the evolution of various antigenic types of CPV. Full length VP2 gene from field isolates was amplified and cloned for sequence analysis. The sequences were submitted to the GenBank and were assigned Acc. Nos., viz. KP406928.1 for P12, KP406927.1 for P15, KP406930.1 for P32, KP406926.1 for Megavac-6 and KP406929.1 for NobivacDHPPi. Phylogenetic analysis indicated that the samples were forming a separate clad with vaccine strains. When the samples were compared with the world and Indian isolates, it was observed that samples formed a separate node indicating regional genetic variation in CPV.

Simultaneous dual syringe electrospinning system using benign solvent to fabricate nanofibrous P(3HB-co-4HB)/collagen peptides construct as potential leave-on wound dressing

The main focus of this study is the incorporation of collagen peptides to fabricate P(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] nano-fiber construct to further enhance surface wettability and support cell growth while harbouring desired properties for biodegradable wound dressing. Simultaneous electrospinning of nanofiber P(3HB-co-4HB)/collagen peptides construct was carried out using dual syringe system. The wettability of the constructs increased with the increase in 4HB molar fraction from 20mol% 4HB [53.2°], P(3HB-co-35mol%4HB)[48.9°], P(3HB-co-50mol%4HB)[44.5°] and P(3HB-co-82mol%4HB) [37.7°]. In vitro study carried out using mouse fibroblast cells (L929) grown on nanofiber P(3HB-co-4HB)/collagen peptides construct showed an increase in cell proliferation. In vivo study using animal model (Sprague Dawley rats) showed that nanofibrous P(3HB-co-4HB)/collagen peptides construct had a significant effect on wound contractions with the highest percentage of wound closure of 79%. Hence, P(3HB-co-4HB)/collagen peptides construct suitable for wound dressing have been developed using nano-fabrication technique.

Pregnancy Induced Ocular Changes and Associated Risk of Ocular Medications

Pregnancy is associated with various ocular changes which can be either physiological or pathological or modification in pre existing conditions. These changes are mostly transient, however some can become permanent. Physiological ocular changes include change in ocular adenexa, tear film composition, cornea, refraction and intraocular pressure. Pathological ocular changes occur as a result of pregnancy induced hypertension, pseudotumour cerebri, vascular occlusive disorders and amniotic fluid embolism. Some of the pre-existing ocular conditions worsen during pregnancy which include diabetic retinopathy, grave’s disease, toxoplasmosis, pituitary tumours, meningioma and uveal tumours. Others show improvement in pregnancy such as uveitis, optic neuritis and multiple sclerosis. Yet others are associated with exacerbations during postpartum period as optic neuritis. Knowledge of these changes is important for both ophthalmologists and gynaecologists for proper management of these patients. Also the treatment modalities for various disorders differ between pregnant and non pregnant females. The ophthalmic medications should be used cautiously during pregnancy and lactation to avoid harmful effects in the mother and the fetus. The materials published in Pubmed, Google Scholar webpages and standard books have been used for preparing this paper.

Mutant prevention concentration, pharmacokinetic-pharmacodynamic integration, and modeling of enrofloxacin data established in diseased buffalo calves

The pharmacokinetic-pharmacodynamic (PK/PD) modeling of enrofloxacin data using mutant prevention concentration (MPC) of enrofloxacin was conducted in febrile buffalo calves to optimize dosage regimen and to prevent the emergence of antimicrobial resistance. The serum peak concentration (Cmax ), terminal half-life (t1/2 K10) , apparent volume of distribution (Vd(area) /F), and mean residence time (MRT) of enrofloxacin were 1.40 ± 0.27 μg/mL, 7.96 ± 0.86 h, 7.74 ± 1.26 L/kg, and 11.57 ± 1.01 h, respectively, following drug administration at dosage 12 mg/kg by intramuscular route. The minimum inhibitory concentration (MIC), minimum bactericidal concentration, and MPC of enrofloxacin against Pasteurella multocida were 0.055, 0.060, and 1.45 μg/mL, respectively. Modeling of ex vivo growth inhibition data to the sigmoid Emax equation provided AUC24 h /MIC values to produce effects of bacteriostatic (33 h), bactericidal (39 h), and bacterial eradication (41 h). The estimated daily dosage of enrofloxacin in febrile buffalo calves was 3.5 and 8.4 mg/kg against P. multocida/pathogens having MIC90 ≤0.125 and 0.30 μg/mL, respectively, based on the determined AUC24 h /MIC values by modeling PK/PD data. The lipopolysaccharide-induced fever had no direct effect on the antibacterial activity of the enrofloxacin and alterations in PK of the drug, and its metabolite will be beneficial for its use to treat infectious diseases caused by sensitive pathogens in buffalo species. In addition, in vitro MPC data in conjunction with in vivo PK data indicated that clinically it would be easier to eradicate less susceptible strains of P. multocida in diseased calves.

Investigation of trypsin-CdSe quantum dot interactions via spectroscopic methods and effects on enzymatic activity

The paper presents the interactions between trypsin and water soluble cadmium selenide (CdSe) quantum dots investigated by spectrophotometric methods. CdSe quantum dots have strong ability to quench the intrinsic fluorescence of trypsin by a static quenching mechanism. The quenching has been studied at three different temperatures where the results revealed that electrostatic interactions exist between CdSe quantum dots and trypsin and are responsible to stabilize the complex. The Scatchard plot from quenching revealed 1 binding site for quantum dots by trypsin, the same has been confirmed by making isothermal titrations of quantum dots against trypsin. The distance between donor and acceptor for trypsin-CdSe quantum dot complexes is calculated to be 2.8 nm by energy transfer mechanisms. The intrinsic fluorescence of CdSe quantum dots has also been enhanced by the trypsin, and is linear for concentration of trypsin ranging 1-80 μl. All the observations evidence the formation of trypsin-CdSe quantum dot conjugates, where trypsin retains the enzymatic activity which in turn is temperature and pH dependent.