Polyethyleneglycol crosslinked N-(2-hydroxyethyl)-polyethylenimine nanoparticles as efficient non-viral vectors for DNA and siRNA delivery in vitro and in vivo

A series of electrostatically crosslinked nanoparticles, N-(2-hydroxyethyl)-polyethylenimine-PEG600 (HePP), was prepared by allowing N-(2-hydroxyethyl)-polyethylenimine (HeP) to interact with polyethyleneglycol (600) dicarboxylic acid (HOOC-PEG600-COOH, PEG600dc), they were then evaluated for their capability to transfect cells in vitro and in vivo. DLS studies revealed the size of the HePP nanoparticles in the range 106-170 nm, which efficiently condensed nucleic acids and provided sufficient protection against nuclease degradation. HePP-pDNA complexes exhibited a considerably higher transfection efficiency and cell viability in various mammalian cell lines, with HePP-3-pDNA displaying the highest gene expression, which outperformed HeP and the commercially available transfection reagent, Lipofectamine™. Also, HePP-3 mediated sequential delivery of GFP specific siRNA resulted in ∼76% suppression of the target gene. Intravenous administration of HePP-3-pDNA complex to mice, followed by monitoring of the reporter gene analysis post 7d, revealed the highest gene expression occurred in the spleen. Together, these results advocate the potential of HePP nanoparticles as efficient vectors for gene delivery in vitro and in vivo.

Vibrational and electronic spectroscopic studies of melatonin

We report the infrared absorption and Raman spectra of melatonin recorded with 488 and 632.8 nm excitations in 3600-2700 and 1700-70 cm(-1) regions. Further, we optimized molecular structure of the three conformers of melatonin within density functional theory calculations. Vibrational frequencies of all three conformers have also been calculated. Observed vibrational bands have been assigned to different vibrational motions of the molecules on the basis of potential energy distribution calculations and calculated vibrational frequencies. Observed band positions match well with the calculated values after scaling except NH stretching mode frequencies. It is found that the observed and calculated frequencies mismatch of NH stretching is due to intermolecular interactions between melatonin molecules.

Identification of potential HIV-1 integrase strand transfer inhibitors: in silico virtual screening and QM/MM docking studies

HIV-1 integrase (IN) is a retroviral enzyme that catalyses integration of the reverse-transcribed viral DNA into the host genome, which is necessary for efficient viral replication. In this study, we have performed an in silico virtual screening for the identification of potential HIV-1 IN strand transfer (ST) inhibitors. Pharmacophore modelling and atom-based 3D-QSAR studies were carried out for a series of compounds belonging to 3-Hydroxypyrimidine-2,4-diones. Based on the ligand-based pharmacophore model, we obtained a five-point pharmacophore with two hydrogen bond acceptors (A), one hydrogen bond donor (D), one hydrophobic group (H) and one aromatic ring (R) as pharmacophoric features. The pharmacophore hypothesis AADHR was used as a 3D query in a sequential virtual screening study to filter small molecule databases Maybridge, ChemBridge and Asinex. Hits matching with pharmacophore hypothesis AADHR were retrieved and passed progressively through Lipinski's rule of five filtering, molecular docking and hierarchical clustering. The five compounds with best hits with novel and diverse chemotypes were subjected to QM/MM docking, which showed improved docking accuracy. We further performed molecular dynamics simulation and found three compounds that form stable interactions with key residues. These compounds could be used as a leads for further drug development and rational design of HIV-1 IN inhibitors.

Open grade III fractures of femoral shaft: Outcome after early reamed intramedullary nailing

BACKGROUND

Open grade III fractures of femur are a challenging therapeutic problem as most of them are associated with multiple trauma. Method used for skeletal stabilization of these fractures should limit further soft tissue damage, bacterial spread and morbidity in addition to its ease of application, providing mechanical support and restoring normal alignment.

METHODS

Forty-six patients with open grade III fractures of femoral shaft were included in the study. There were 10 grade IIIA, 34 grade IIIB and two grade IIIC fractures that were treated with early reamed intramedullary nailing with adequate management of soft tissue. Patients were reviewed retrospectively.

RESULTS

Mean time of union was 27 weeks. Infection rate was 4% and non-union rate was 9%. There were two cases (4%) with limb shortening. No case of angular or rotational deformity was noted.

CONCLUSION

Early reamed intramedullary nailing for open grade III fractures of femoral shaft, after giving due respect to the soft tissue injury, gives satisfactory results with proper alignment, good range of motion, short rehabilitation period and low infection rate.

LEVEL OF EVIDENCE

Level IV. Retrospective therapeutic study.

Linear polyethylenimine-graft-chitosan copolymers as efficient DNA/siRNA delivery vectors in vitro and in vivo

Chitosan was partially converted to its chlorohydrin derivative by the reaction with epichlohydrin, which was subsequently reacted with varying amounts of lPEI(2.5 kD) to obtain a series of chitosan-lPEI(2.5 kD) copolymers (CP). These copolymers were then characterized and evaluated in terms of transfection efficiency (in vitro and in vivo), cell viability, DNA release and buffering capacity. The CP-4 copolymer (the best among the CP series) showed enhanced transfection (-2 - 24 folds) in comparison with chitosan, lPEI(2.5 kD), bPEI(25 kD) and Lipofectamine in HEK293, HeLa and CHO cells. The buffering capacity (in the pH range of 3 - 7.5), as shown by confocal microscopy, and DNA-release capability of the CP copolymers, was found to be significantly enhanced over chitosan. Intravenous administration of CP-4/DNA polyplex in mice followed by the reporter gene analysis showed the highest gene expression in spleen. Collectively, these results demonstrate the potential of CP-4 copolymer as a safe and efficient nonviral vector. From the Clinical Editor: Chitosan -PEI (2.5 kD) copolymers (CP) were characterized and their transfection efficiency, DNA release and buffering capacity were studied. The CP-4 copolymer significantly enhanced buffering capacity and provided the highest gene expression levels. The method may be used to enhance DNA transfection.

Linear PEI nanoparticles: efficient pDNA/siRNA carriers in vitro and in vivo

Linear polyethylenimine (lPEI, 25 kDa) nanoparticles' (LPN) series was synthesized by varying percentage of cross-linking with 1,4-butanediol diglycidyl ether (BDE) and their size, surface charge, morphology, pDNA protection/release, cytotoxicity and transfection efficiency were evaluated. Synthesized nanoparticles (NPs) were spherical in shape (size: ∼109 - 235 nm; zeta potential: +38 to +16 mV). These NPs showed increased buffering capacity with increasing percent cross-linking and also exhibited excellent transfection efficiency (i.e., ∼1.3 - 14.7 folds in case of LPN-5) in comparison with lPEI and the commercial transfection agents used in this study. LPN-5 based GFP-specific siRNA delivery resulted in ∼86% suppression of targeted gene expression. These particles were relatively nontoxic in vitro (in cell lines) and in vivo (in Drosophila). In vivo gene expression studies using LPN-5 in Balb/c mice through intravenous injection showed maximum expression of the reporter gene in the spleen. These results together demonstrate the potential of these particles as efficient transfection reagents.

FROM THE CLINICAL EDITOR

The authors demonstrate a novel method of synthesizing linear PEI nanoparticles to utilize these as transfection agents.

Gellan gum-PEI nanocomposites as efficient gene delivery agents

Of the non-viral vectors, a cationic polymer like PEI is an attractive candidate which however, has been negatively impacted due to its marked toxicity. An anionic sugar polymer gelan gum (GG) has been introduced into PEI system to increase transfection efficiency with minimal toxicity. We showed that one of the synthesized (GP1-GP6) GG-PEI nanocomposites (NCs), GP3, exhibited negligible toxicity in in vitro (primary keratinocytes, HEK293, HeLa and HepG2 cells) and in vivo (Drosophila melanogaster) as compared to PEI or lipofectamin. GP3-pDNA complex was found to be transfected efficiently in the above cells as confirmed by FACS analysis (72.0 + 5.5%) while lipofectamine showed only 12.4 + 3.5% efficiency. GP3 mediated GFP specific siRNA delivery resulted in the knockdown of the GFP expression by approximately 77% and JNK (60%). In vivo gene expression studies in mice revealed reporter gene expression in spleen. The study demonstrates that GG blended PEI NCs hold promise for future applications in gene delivery both in vitro and in vivo.

Assessment of contamination of soil due to heavy metals around coal fired thermal power plants at Singrauli region of India

In the present study, an attempt was made to measure contamination of soil around four large coal-based Thermal Power Plants. The concentration of Cadmium, Lead, Arsenic and Nickel was estimated in all four directions from Thermal Power Plants. The soil in the study area was found to be contaminated to varying degrees from coal combustion byproducts. The soil drawn from various selected sites in each direction was largely contaminated by metals, predominantly higher within 2-4 km distance from Thermal Power Plant. Within 2-4 km, the mean maximum concentration of Cadmium, Lead, Arsenic and Nickel was 0.69, 13.69, 17.76, and 3.51 mg/kg, respectively. It was also observed that concentration was maximum in the prevalent wind direction. The concentration of Cadmium, Lead, Arsenic and Nickel was highest 0.69, 13.23, 17.29 and 3.56 mg/kg, respectively in west direction where wind was prevalent.

Zinc phthalocyanine thin film and chemical analyte interaction studies by density functional theory and vibrational techniques

Thin films of zinc phthalocyanine have been deposited on KBr and glass substrates by the thermal evaporation method and characterized by the x-ray diffraction, optical, infrared and Raman techniques. The observed x-ray diffraction and infrared absorption spectra of as-deposited thin films suggest the presence of an α crystalline phase. Infrared and Raman spectra of thin films after exposure to vapours of ammonia and methanol have also been recorded. Shifts in the position of some IR and Raman bands in the spectra of exposed films have been observed. Some bands also show changes in their intensity on exposure. Increased charge on the phthalocyanine ring and out-of-plane distortion of the core due to interaction between zinc phthalocyanine and vapour molecules involving the fifth coordination site of the central metal ion may be responsible for the band shifts. Changes in the intensity of bands are interpreted in terms of the lowering of molecular symmetry from D(4h) to C(4v) due to doming of the core. Molecular parameters and Mulliken atomic charges of zinc phthalocyanine and its complexes with methanol and ammonia have been calculated from density functional theory. The binding energy of the complexes have also been calculated. Calculated values of the energy for different complexes suggest that axially coordinated vapour molecules form the most stable complex. Calculated Mulliken atomic charges show net charge transfer from vapour molecules to the phthalocyanine ring for the most stable complex.

Effect of pyridine on infrared absorption spectra of copper phthalocyanine

Infrared absorption spectra of copper phthalocyanine in KBr pellet and pyridine solution in 400-1625 and 2900-3200 cm(-1)regions are reported. In the IR spectra of solid sample, presence of weak bands, which are forbidden according to the selection rules of D4h point group, is explained on the basis of distortion in the copper phthalocyanine molecule caused by the crystal packing effects. Observation of a new band at 1511 cm(-1) and change in intensity of some other bands in pyridine are interpreted on the basis of coordination of the solvent molecule with the central copper ion.

The effect of aluminium phosphide on the human brain: a histological study

The study was conducted on 317 cases of poisoning in the Varanasi region, India, between January 2002 and August 2003. Aluminium phosphide (Celphos) was used by 239 victims (75.40% of the total) and was used in 69.03% of male and 30.96% of female cases. It was commoner in males from both rural and urban areas and in the 21-30 year age group. Microscopic investigation of the cerebral and cerebellar cortex showed distinct changes due to the effect of celphos. Findings in the cerebral cortex revealed disorganisation of the different layers, round shaped neurons with a convex border, degenerated Nissl granules in the cytoplasm and a deeply stained degenerated eccentric nucleus. Findings in the cerebellar cortex included degenerated neurons, the infiltration of round cells into the molecular layer and the disappearance of the processes of Purkinje cells. Degenerate nuclei were surrounded by scavenger cells in the granular layer. The subcortical zone of the brain revealed a paucity of glial cells, degeneration of nerve fibres and the appearance of necrotic patches.

A study on drug use in a district hospital of West Bengal

A cross-sectional study at Howrah General Hospital, West Bengal for prescription analysis and assessment of drug dispensing in 341 patients revealed that the average number of drugs prescribed per encounter was 2.98 +/- 1.69, 38.2% drugs were in generic name and majority were from essential drugs list. 18.6% and 5.2% encounters used antibiotics and injections respectively. Average consultation and dispensing time were short. Majority of drugs were dispensed but unlabeled. 46.8% patients knew correct dosage of drugs. Only 4.7% patients were treated without drugs. Average drug cost per encounter was Rs. 31.32+30.89 where antibiotics and injections shared 36.5% and 4.6% respectively.

Infrared spectroscopic studies of free-base tetraphenylporphine and its dication

We present here the infrared absorption spectra of free-base tetraphenylporphine and its dication. Most of the allowed IR bands of porphyrin skeletal are observed in pairs due to two-fold symmetry of the free-base tetraphenylporphine. Observation of some new bands, disappearance of few bands in the IR spectrum of dication are interpreted on the basis of point group symmetry S4. Intensity change in the observed bands due to vibrational motion of the phenyl rings for dication is also explained on the basis of symmetry of dication. Sharing of electrons of the B(1u) orbitals by the two added protons are responsible for the shifts in the position of certain IR bands for dication.

Spectroscopic studies of rhodamine 6G dispersed in polymethylcyanoacrylate

We report here electronic absorption, fluorescence and resonance Raman studies of rhodamine 6G laser dye dispersed in the polymethylcyanoacrylate matrix. In the electronic absorption and fluorescence spectra of dispersed rhodamine 6G, band maxima are red shifted compared to solution. Raman spectra show some new bands. These spectral changes arise due to matrix effect and interaction between rhodamine 6G and the host material involving amine group of rhodamine.

Anatomical variations in termination of the axillary artery and its clinical implications

Variations in the termination of the axillary artery (AA) were observed in 51 out of 356 axilla during routine dissections. The incidence of variation was higher on the right axilla in 17.42% cases (CI: 11.60-22.51) than the left axilla 11.24% cases (CI: 6.46-15.55) and was found to be 12.33% in male and 40.63% in female cadavers. The variations were divided into four groups. The first group showed that the terminal end of the AA divided into lateral and medial divisions in 6.16% (CI: 2.21-9.82) male and in 15.63% (CI: 2.76-25.25) female cadavers. The second group variation showed that the terminal end of the axillary artery divided into deep and superficial divisions in 2.74% (CI: 0.10-5.27) male and in 6.25% (CI: -1.87-13.13) female cadavers. The third group showed that the terminal end of the AA divided into three branches in 2.74% (CI: 0.10-5.27) male and in 6.25% (CI: -1.87-13.13) female cadavers. The fourth group showed the tapering of the terminal end of AA in 0.68% (CI: -0.63-1.99) male and 12.50% (CI: 0.97-21.46) female cadavers. The variable origin of the circumflex humeral, subscapular and profunda brachii arteries was also observed. These variations in the terminal end of the axillary artery are not only of significant clinical importance to orthopaedic and reconstructive surgeons but also have very significant medico-legal implications.

Prescribing and dispensing activities at the health facilities of a non-governmental organization

BACKGROUND

Prescribing and dispensing surveys are pre-requisites to achieving rational drug use. There is a dearth of such studies in India, particularly in the non-governmental organization sector.

METHODS

We carried out a survey at the outpatient facilities maintained by the Southern Health Improvement Samity, a non-governmental organization in the South 24 Parganas district of West Bengal. Data were collected prospectively by interviewing patients immediately after patient-physician and patient-dispenser encounters. Pre-designed forms were used to collect data pertaining to World Health Organization drug-use indicators and some additional indices. The calculations of cost of therapy involved some approximation.

RESULTS

Of the 312 prescriptions analysed, the majority were signed, legible and complete with respect to age/gender data; 95.5% used Latin abbreviations and 7.7% mentioned neither signs and symptoms nor diagnosis. The average number of drugs per encounter was 3.2; only 2 patients were treated without drugs; 46.2% of drugs were prescribed by generic name. Use of antibiotics (72.8% of encounters) and irrational fixed dose combinations (45.6% of prescribed drugs) were frequent, but injection use (3.9% of prescriptions) was low. The average drug cost per encounter was Rs 74.19, of which antibiotics comprised 37.1%. The availability of first-line antitubercular drugs was adequate but other key drugs were in limited supply. Essential drugs lists and formularies were not followed. Only 45.7% of prescribed drugs conformed to the World Health Organization model list of essential drugs. Only 12 preparations accounted for 70.9% of the prescribed drugs, including therapeutically doubtful ones such as cough syrups, multivitamins and carminative syrups. For the dispensing survey, 301 prescriptions were analysed separately. All the prescribed drugs were supplied for only 11.6% of prescriptions. There were no serious errors in dispensing but 43.8% of dispensed products were inadequately labelled. Patients knew the correct mode of use for 64.5% of dispensed drugs. The average consultation and dispensing times were 3.7 and 3.1 minutes, respectively.

CONCLUSION

Frequent use of antibiotics, irrational fixed dose combinations and preparations of uncertain efficacy, inadequate labelling of dispensed drugs and lack of access to standard tools for rational drug use such as locally adapted essential drugs list, formularies and standard treatment guidelines were some of the problematic prescribing and dispensing trends identified through this survey. Educational interventions are required to rectify these problems.

Evaluation of antimuscarinic activity in human volunteers: a teaching aid in clinical pharmacology

The antimuscarinic activity of oxyphenonium bromide, diphenhydramine hydrochloride and astemizole were evaluated in six volunteers. The parameters used were salivary secretion, heart rate and pupillary size. The results indicated that the changes in heart rate and pupillary size and measurements were not convenient parameters for class room demonstration. However, salivary secretion and dryness of mouth were found to be reliable parameters for measurement. It was concluded that simple procedures like evaluation of antimuscarinic activity could be introduced as teaching aids in clinical pharmacology for undergraduate students.

Influence of high fat diet on steady state bioavailability of lithium carbonate in manic depressive patients - a preliminary report

The effect of high fat food in the steady state bioavailability of lithium carbonate (900 or 1200mg daily, in divided doses) was studied in three patients of manic-depressive psychosis in a self-control cross-over design. Serial blood samples were collected by venepuncture until 8 hours following drug administration and lithium was assayed by flame photometry. The results indicated a reduction in the extent of bioavailability of lithium by the high fat food as compared to standard normal diet, in all the three patients studied Caution should be exercised in regard to lithium administration along with food rich in fat content.