Detection of Biofilm Production and Antibiotic Susceptibility Pattern among Clinically Isolated Staphylococcus aureus.

Aim: The increasing antibiotic resistance and the ability to form biofilms in medical devices have become the leading cause of severe infections associated with Staphylococcus aureus (S. aureus). Since the bacteria living in biofilms can exhibit 10- to 1,000-fold increase in antibiotic resistance and implicate chronic infectious diseases, the detection of S. aureus ability to form biofilms is of great importance for managing, minimizing, and effectively treating infections caused by it. This study aimed to compare the tube and tissue culture methods to detect biofilm production and antibiotic susceptibility in MRSA and MSSA. Materials and Methods: The S. aureus isolates were identified by the examination of the colony morphology, Gram staining, and various biochemical tests. Antimicrobial susceptibility testing of all isolates was performed by the modified Kirby-Bauer disc diffusion method as recommended by CLSI guidelines. MRSA screening was performed phenotypically using a cefoxitin disc (30 µg). Isolates were tested for inducible resistance using the D-test, and two phenotypic methods detected biofilm formation. Results: Among 982 nonrepeated clinical specimens, S. aureus was isolated from 103 (10.48%). Among 103 clinical isolates of S. aureus, 54 (52.42%) isolates were MRSA, and 49 (47.57%) were MSSA. Among 54 MRSA isolates, the inducible MLSB phenotype was observed in 23/54 (42.59%) with a positive D-test. By TCP method, 26 (48.1%) MRSA isolates were strong biofilm producers, whereas, among all MSSA isolates, only 6 (12.2%) were strong biofilm producers. Conclusion: MRSA showed strong biofilm production in comparison with MSSA. The TCP method is a recommended reliable method to detect the biofilm among S. aureus isolates, and the TM method could be useful for the screening of biofilm production in S. aureus in the routine clinical laboratory.

Genipin-crosslinked albumin nanoparticles containing neratinib and silibinin: A dual-death therapy for triple negative breast cancer.

Triple negative breast cancer (TNBC) cells resist chemotherapy by hijacking apoptosis. Alternative cell death forms like ferroptosis offer new treatment options. A combined therapy using neratinib (NTB; ferroptosis inducer) and silibinin (SLB; apoptosis inducer) via albumin-based nanocarriers (N-S Alb NPs) was explored to target TNBC. N-S Alb NPs had optimal size (134.26 ± 10.23 nm), PDI (0.224 ± 0.01), and % entrapment efficiency (∼80 % for NTB and ∼87 % for SLB). Transmission electron microscopy confirmed their spherical shape. In vitro release studies showed sustained drug release without hemolysis risk. N-S Alb NPs had higher cellular uptake and cytotoxicity than individual drugs or their mixture. IC50 values for N-S Alb NPs were significantly reduced in MDA-MB-231 (∼2.23-fold) and 4T1 (∼1.85-fold) cell lines and apoptosis index were significantly higher in MDA-MB-231 (∼1.31-fold) and 4T1 cell line (∼1.35-fold) than the physical mixture of both drugs (NTB + SLB). N-S Alb NPs generated more reactive oxygen species (ROS) and caused mitochondrial membrane depolarization, indicating increased cell death. They also exhibited better ferroptosis induction by reducing glutathione (GSH), increasing Fe2+ activity and MDA levels in TNBC cells. Thus, N-S Alb NPs had the ability to promote "mixed" type cell death, showed promise in enhancing the payload capabilities and targeting in TNBC.

Clinicopathological Profile of the von Willebrand Disease in a Tertiary Care Centre in Varanasi.

Objective The von Willebrand disease (vWD) is one of the most common inherited bleeding disorders in India; however, the diagnostic tests and its interpretation require specialized laboratory and personnel which are not readily available in the eastern part of North India. The purpose of this study is to estimate the relative prevalence of vWD and study the clinical and laboratory features including advanced diagnostic tests. Methods All patients referred to the pathology department for evaluation of bleeding were evaluated for vWD during a period of 4 years. Clinical and laboratory features were analyzed and reported. Results A total of 1,126 cases of bleeding manifestations were evaluated, and 237 cases of inherited bleeding disorders were diagnosed; vWD was diagnosed in 38 (16%) of these 237 cases. Advanced diagnostic tests were done in all of these cases. Conclusion The vWD is among the most common inherited bleeding disorders in the country, second only to hemophilia A. Type-1 vWD was the most frequent with 25 cases (65.7%), followed by type-2N with 7 cases (18.4%).

Appraisal of Felodipine Nanocrystals for Solubility Enhancement and Pharmacodynamic Parameters on Cadmium Chloride Induced Hypertension in Rats.

AIM: Felodipine (FDP), an antihypertensive drug possesses low water solubility and extensive first-pass metabolism leading to poor bioavailability. This impelled us to improve its solubility, bioavailability, and pharmacodynamic properties through the Nanocrystal (NC) approach. METHODS: FDP-NC were prepared with Poloxamer F125 (PXM) by the antisolvent precipitation method. The experimental setup aimed at fine-tuning polymer concentration, the proportion of antisolvent to solvent, and the duration of ultrasonication for NC formulation. RESULTS: Optimized formulation was characterized for particle size, solubility, and PDI. Particle reduction of 74.96 times was achieved with a 9X solubility enhancement as equated to pure FDP. The morphology of NC was found to be crystalline through scanning electron microscopy observation. The formation of the crystal lattice in FDP-NC was further substantiated by the XRD and DSC results. Lowering of the heat of fusion of FDP-NC is a clear indication of size reduction. The stability studies showed no substantial change in physical parameters of the FDP-NC as assessed by particle size, zeta potential, and drug content. CONCLUSION: The crystalline nature and improved solubility of FDP-NC improve the dissolution profile and pharmacodynamic data. The stability study data ensure that FDP-NC can be safely stored at 25°C. It is revealed that FDP-NC had a better release profile and improved pharmacodynamic effects as evident from better control over heart rate than FDP.

Effect of foam insertion in aneurysm sac on flow structures in parent lumen: relating vortex structures with disturbed shear.

Numerous studies suggest that disturbed shear, causing endothelium dysfunction, can be related to neighboring vortex structures. With this motivation, this study presents a methodology to characterize the vortex structures. Precisely, we use mapping and characterization of vortex structures' changes to relate it with the hemodynamic indicators of disturbed shear. Topological features of vortex core lines (VCLs) are used to quantify the changes in vortex structures. We use the Sujudi-Haimes algorithm to extract the VCLs from the flow simulation results. The idea of relating vortex structures with disturbed shear is demonstrated for cerebral arteries with aneurysms virtually treated by inserting foam in the sac. To get physiologically realistic flow fields, we simulate blood flow in two patient-specific geometries before and after foam insertion, with realistic velocity waveform imposed at the inlet, using the Carreau-Yasuda model to mimic the shear-thinning behavior. With homogenous porous medium assumption, flow through the foam is modeled using the Forchheimer-Brinkman extended Darcy model. Results show that foam insertion increases the number of VCLs in the parent lumen. The average length of VCL increases by 168.9% and 55.6% in both geometries. For both geometries under consideration, results demonstrate that the region with increased disturbed shear lies in the same arterial segment exhibiting an increase in the number of oblique VCLs. Based on the findings, we conjecture that an increase in oblique VCLs is related to increased disturbed shear at the neighboring portion of the arterial wall.

Assessment and visualization of hemodynamic loading in aneurysm sac and neck: Effect of foam insertion.

Shape memory polymer (SMP) foam is often proposed as the future alternative of coils in aneurysm treatment devices. Present work numerically investigates the unsteady, three-dimensional simulation of blood flow in a cerebral aneurysm filled with SMP foam. Simulations are conducted on patient-specific geometries with realistic blood velocity waveform imposed at the inlet while SMP foam is treated as a porous medium. The present study introduces a "loading risk map" that helps to visualize the hemodynamic effect of foam insertion on the aneurysm sac and neck. The loading risk maps suggest that while the SMP foam subdues the flow and wall shear pulsations in the aneurysm sac, the pressure distribution is minimally affected. The maps suggest that while the downstream lip is the most risk-prone site for both geometries, downstream vascular anatomy significantly influences foam efficiency in reducing pressure and wall shear stress loading.

Inorganic clay nanocomposite system for improved cholinesterase inhibition and brain pharmacokinetics of donepezil.

Objective: Brain drug delivery for effective treatment of neurodegenerative disorders is limited due to the selective permeability of blood brain barrier (BBB). During the past few years, development of novel delivery system has attracted considerable attention of formulation scientists to overcome the permeability limitation caused by BBB.Significance: Based on the outcomes of this study and taking into consideration of the unique characteristics of laponite, it can be further explored to deliver many other central nervous system acting drugs.Methods: In the present study, laponite (LAP) nanocomposites were exploited for the improved brain delivery of donepezil (DZ) following encapsulation approach due to their nano-size and positive charge at pH <9.Result: The size of prepared nanocomposites was 53.7 ± 4.0 to 137.7 ± 11.0 nm. The drug was released in a sustained manner till 120 h in phosphate buffer saline (pH 7.4) and acid phthalate buffer (pH 4.0). LAPDZ formulations inhibited acetylcholinesterase approximately by 82%, significantly higher (p < 0.05) than plain DZ (30%). Swiss albino mice exhibited enhanced brain uptake of LAPDZ administered via intravenous route. Promising pharmacokinetic parameters were observed in animals treated with LAPDZ. LAPDZ formulation showed half-life (t1/2), volume of distribution (Vd) and clearance (Cl) as 5.53 ± 0.40 h-1, 0.129 ± 0.02 L, 0.015 ± 0.002 L/h, respectively. While DZ solution showed the same parameters as 1.06 ± 0.12 h-1, 0.168 ± 0.01 L, 0.106 ± 0.013 L/h, respectively. The brain uptake of LAPDZ formulation was improved with quintuplet t1/2.Conclusion: Based on the results of present study, it is proposed that the formulated nanocomposite would result in improved patient compliance with therapeutic effect at lower doses.

HPMA-PLGA Based Nanoparticles for Effective In Vitro Delivery of Rifampicin.

PURPOSE: Tuberculosis (TB) chemotherapy witnesses some major challenges such as poor water-solubility and bioavailability of drugs that frequently delay the treatment. In the present study, an attempt to enhance the aqueous solubility of rifampicin (RMP) was made via co-polymeric nanoparticles approach. HPMA (N-2-hydroxypropylmethacrylamide)-PLGA based polymeric nanoparticulate system were prepared and evaluated against Mycobacterium tuberculosis (MTB) for sustained release and bioavailability of RMP to achieve better delivery. METHODOLOGY: HPMA-PLGA nanoparticles (HP-NPs) were prepared by modified nanoprecipitation technique, RMP was loaded in the prepared NPs. Characterization for particle size, zeta potential, and drug-loading capacity was performed. Release was studied using membrane dialysis method. RESULTS: The average particles size, zeta potential, polydispersity index of RMP loaded HPMA-PLGA-NPs (HPR-NPs) were 260.3 ± 2.21 nm, -6.63 ± 1.28 mV, and 0.303 ± 0.22, respectively. TEM images showed spherical shaped NPs with uniform distribution without any cluster formation. Entrapment efficiency and drug loading efficiency of HPR-NPs were found to be 76.25 ± 1.28%, and 26.19 ± 2.24%, respectively. Kinetic models of drug release including Higuchi and Korsmeyer-peppas demonstrated sustained release pattern. Interaction studies with human RBCs confirmed that RMP loaded HP-NPs are less toxic in this model than pure RMP with (p < 0.05). CONCLUSIONS: The pathogen inhibition studies revealed that developed HPR-NPs were approximately four times more effective with (p < 0.05) than pure drug against sensitive Mycobacterium tuberculosis (MTB) stain. It may be concluded that HPR-NPs holds promising potential for increasing solubility and bioavailability of RMP.

MCM-41 Nanoparticles for Brain Delivery: Better Choline-Esterase and Amyloid Formation Inhibition with Improved Kinetics.

The present study was aimed at delivering a low bioavailability drug, rivastigmine hydrogen tartrate (RTG), to the brain through its encapsulation in mesoporous silica nanoparticles (MSNs) and targeted to amyloid inhibition in the brain. MSNs were characterized for size, zeta potential, and drug entrapment using SEM, TEM, HR-TEM, FT-IR, and PXRD. Drug-loaded MSNs were assessed for in vitro release kinetics and ex vivo followed by animal studies. The average size of the prepared blank (MCM-41B) and drug-loaded MSNs (MCM-41L) was 114 ± 2.0 and 145 ± 0.4 nm with the zeta potential of approximately -43.5 ± 1.1 and -37.6 ± 1.4 mV, respectively. MCM-41L exhibited an average entrapment efficiency of 88%. In vitro release studies exhibited early surge followed by a sluggish persistent or constant release (biphasic pattern). Hemolytic studies proved that the developed MCM-41L NPs are less hemolytic compared to RTG. A reduced ThT fluorescence was observed with MCM-41L compared to MCM-41B and RTG in the amyloid inhibition studies. A significant (p < 0.05) inhibition of AChE (acetycholinesterase) was observed for MCM-41L (80 ± 4.98%), RTG (62 ± 3.25%), and MCM-41B (54 ± 4.25%). In vivo pharmacokinetics in Wistar rats revealed that the AUC and mean residence time (MRT) for MCM-41L was sustained and significantly higher (p < 0.05) (780 ± 3.30 ng/L; 5.49 ± 0.25 h) compared to RTG solution (430 ± 3.50 ng/L; 0.768 ± 0.17 h). Similarly, the half-life was found to be significantly higher in case of MCM-41L. The promising result was brain delivery of RTG in Wistar rats which was enhanced almost 127 folds in vivo, using MCM-41L nanoparticles. MCM-41L nanoparticles effectively enhanced the bioavailability of RTG. Conclusively, these can be used for the administration of RTG and other related low bioavailability drugs for improved brain delivery.

Blood brain barrier: An overview on strategies in drug delivery, realistic in vitro modeling and in vivo live tracking.

Blood brain barrier (BBB) is a group of astrocytes, neurons and endothelial cells, which makes restricted passage of various biological or chemical entities to the brain tissue. It gives protection to brain at one hand, but at the other hand it has very selective permeability for bio-actives and other foreign materials and is one of the major challenges for the drug delivery. Nanocarriers are promising to cross BBB utilizing alternative route of administration such as intranasal and intra-carotid drug delivery which bypasses BBB. In future more optimized drug delivery system can be achieved by compiling the best routes with the best carriers. Single photon emission tomography (SPECT) and different brain-on-a-chip in vitro models are being very reliable to study live in vivo tracking of BBB and its pathophysiology, respectively. In the current review we have tried to exploit mechanistically all these to understand and manage the various BBB disruptions in diseased condition along with crossing the hurdles occurring in drug or gene delivery across BBB.