Monitoring microbial growth on a microfluidic lab-on-chip with electrochemical impedance spectroscopic technique.

A continuous rise in the wastes from industrial effluents, bio-waste, and pharmaceuticals has deteriorated surface water and drinking water sources. Standard laboratory tests of total coliform are time-consuming and logistically inefficient for field data generation. Better and portable sensing technologies are needed. This paper reports an electrical impedance spectroscopic technique incorporated in a micro-fluidic chip with interdigitated microelectrodes to monitor the growth of microbial cells. Lag, log, and stationary phases of Escherichia coli cell growth with an integrated electrode are successfully detected, for samples of reverse osmosis water, standard treated tap water, and recycled water respectively. The results indicate that reverse osmosis water has a higher probability of contamination with bacterial pathogens compared to the other two types of water samples when subjected to the same amount of added nutrients. The statistical analysis shows a possible single detection range with higher-order regression, and repeat use of a single chip with the electrode was found to be within an acceptable limit. The interdigitated electrodes exposed to in-situ cell growth conditions and repeated electrical measurements have shown a promise for possible periodic or continuous monitoring. The paper further identifies several complimentary analysis methodologies that are robust towards phase noise in the measured impedance and are suited particularly for early-stage detection of bacterial contamination. The cell adhesion tendencies over the microelectrode due to the electric field need to be further analyzed.

Pathogenic Escherichia coli (E. coli) detection through tuned nanoparticles enhancement study.

OBJECTIVE: This study aims to detect pathogenic Escherichia coli (E. coli) bacteria using non-destructive fluorescence microscopy and micro-Raman spectroscopy. RESULTS: Raman vibrational spectroscopy provides additional information regarding biochemical changes at the cellular level. We have used two nanomaterials zinc oxide nanoparticles (ZnO-NPs) and gold nanoparticles (Au-NPs) to detect pathogenic E. coli. The scanning electron microscope (SEM) with energy dispersive X-ray (EDAX) spectroscopy exhibit surface morphology and the elemental composition of the synthesized NPs. The metal NPs are useful contrast agents due to the surface plasmon resonance (SPR) to detect the signal intensity and hence the bacterial cells. The changes due to the interaction between cells and NPs are further correlated to the change in the surface charge and stiffness of the cell surface with the help of the fluorescence microscopic assay. CONCLUSIONS: We conclude that when two E. coli strains (MTCC723 and MTCC443) and NPs are respectively mixed and kept overnight, the growth of bacteria are inhibited by ZnO-NPs due to changes in cell membrane permeability and intracellular metabolic system under fluorescence microscopy. However, SPR possessed Au-NPs result in enhanced fluorescence of both pathogens. In addition, with the help of Raman microscopy and element analysis, significant changes are observed when Au-NPs are added with the two strains as compared to ZnO-NPs due to protein, lipid and DNA/RNA induced conformational changes.

Validation of polyvinylidene fluoride nasal sensor to assess nasal obstruction in comparison with subjective technique.

OBJECTIVE: The aim of this study is to validate the applicability of the PolyVinyliDene Fluoride (PVDF) nasal sensor to assess the nasal airflow, in healthy subjects and patients with nasal obstruction and to correlate the results with the score of Visual Analogue Scale (VAS). METHODS: PVDF nasal sensor and VAS measurements were carried out in 50 subjects (25-healthy subjects and 25 patients). The VAS score of nasal obstruction and peak-to-peak amplitude (Vp-p) of nasal cycle measured by PVDF nasal sensors were analyzed for right nostril (RN) and left nostril (LN) in both the groups. Spearman's rho correlation was calculated. The relationship between PVDF nasal sensor measurements and severity of nasal obstruction (VAS score) were assessed by ANOVA. RESULTS: In healthy group, the measurement of nasal airflow by PVDF nasal sensor for RN and LN were found to be 51.14±5.87% and 48.85±5.87%, respectively. In patient group, PVDF nasal sensor indicated lesser nasal airflow in the blocked nostrils (RN: 23.33±10.54% and LN: 32.24±11.54%). Moderate correlation was observed in healthy group (r=-0.710, p<0.001 for RN and r=-0.651, p<0.001 for LN), and moderate to strong correlation in patient group (r=-0.751, p<0.01 for RN and r=-0.885, p<0.0001 for LN). CONCLUSION: PVDF nasal sensor method is a newly developed technique for measuring the nasal airflow. Moderate to strong correlation was observed between PVDF nasal sensor data and VAS scores for nasal obstruction. In our present study, PVDF nasal sensor technique successfully differentiated between healthy subjects and patients with nasal obstruction. Additionally, it can also assess severity of nasal obstruction in comparison with VAS. Thus, we propose that the PVDF nasal sensor technique could be used as a new diagnostic method to evaluate nasal obstruction in routine clinical practice.

Osteoprotective effect of propranolol in ovariectomized rats: a comparison with zoledronic acid and alfacalcidol.

BACKGROUND: Currently ß-adrenergic receptor blockers are considered to be potential drugs under investigation for preventive or therapeutic effect in osteoporosis. However, there is no published data showing the comparative study of ß-blockers with well accepted agents for the treatment of osteoporosis. To address this question, we compared the effects of propranolol with well accepted treatments like zoledronic acid and alfacalcidol in an animal model of postmenopausal osteoporosis. METHODS: Five days after ovariectomy, 36 ovariectomized (OVX) rats were divided into 6 equal groups, randomized to treatments zoledronic acid (100 µg/kg, intravenous single dose); alfacalcidol (0.5 µg/kg, oral gauge daily); propranolol (0.1 mg/kg, subcutaneously 5 days per week) for 12 weeks. Untreated OVX and sham OVX were used as controls. At the end of treatment serum calcium and alkaline phosphatase were assayed. Femurs were removed and tested for bone density, bone porosity, bone mechanical properties and trabecular micro-architecture. RESULTS: Propranolol showed a significant decrease in alkaline phosphatase levels and bone porosity in comparison to OVX control. Moreover, propranolol significantly improved bone density, bone mechanical properties and inhibited the deterioration of trabecular microarchitecture when compared with OVX control. The osteoprotective effect of propranolol was comparable with zoledronic acid and alfacalcidol. CONCLUSIONS: Based on this comparative study, the results strongly suggest that propranolol can be a candidate therapeutic drug for the management of postmenopausal osteoporosis.

Polyvinylidene fluoride film based nasal sensor to monitor human respiration pattern: an initial clinical study.

Design and development of a piezoelectric polyvinylidene fluoride (PVDF) thin film based nasal sensor to monitor human respiration pattern (RP) from each nostril simultaneously is presented in this paper. Thin film based PVDF nasal sensor is designed in a cantilever beam configuration. Two cantilevers are mounted on a spectacle frame in such a way that the air flow from each nostril impinges on this sensor causing bending of the cantilever beams. Voltage signal produced due to air flow induced dynamic piezoelectric effect produce a respective RP. A group of 23 healthy awake human subjects are studied. The RP in terms of respiratory rate (RR) and Respiratory air-flow changes/alterations obtained from the developed PVDF nasal sensor are compared with RP obtained from respiratory inductance plethysmograph (RIP) device. The mean RR of the developed nasal sensor (19.65 ± 4.1) and the RIP (19.57 ± 4.1) are found to be almost same (difference not significant, p > 0.05) with the correlation coefficient 0.96, p < 0.0001. It was observed that any change/alterations in the pattern of RIP is followed by same amount of change/alterations in the pattern of PVDF nasal sensor with k = 0.815 indicating strong agreement between the PVDF nasal sensor and RIP respiratory air-flow pattern. The developed sensor is simple in design, non-invasive, patient friendly and hence shows promising routine clinical usage. The preliminary result shows that this new method can have various applications in respiratory monitoring and diagnosis.

Degradation and failure of field emitting carbon nanotube arrays.

It has been observed experimentally that the collective field emission from an array of Carbon Nanotubes (CNTs) exhibits fluctuation and degradation, and produces thermal spikes, resulting in electro-mechanical fatigue and failure of CNTs. Based on a new coupled multiphysics model incorporating the electron-phonon transport and thermo-electrically activated breakdown, a novel method for estimating accurately the lifetime of CNT arrays has been developed in this paper. The main results are discussed for CNT arrays during the field emission process. It is shown that the time-to-failure of CNT arrays increases with the decrease in the angle of tip orientation. This observation has important ramifications for such areas as biomedical X-ray devices using patterned films of CNTs.

Coupled effect of size, strain rate, and temperature on the shape memory of a pentagonal Cu nanowire.

A body-centered pentagonal nanobridge structure with lattice constants c = 2.35 and a = 2.53 A has been observed under high strain rate tensile loading on an initially constrained [Formula: see text] Cu nanowire at various temperatures. Extensive molecular dynamics (MD) simulations have been performed using the embedded atom method (EAM) for cross-sectional dimensions ranging from 0.723 x 0.723 to 2.169 x 2.169 nm(2), temperature ranging from 10 to 600 K, and strain rates of 10(9)-10(7) s(-1). Formations of such pentagonal nanowire are observed for a temperature range 200-600 K for particular cross-sectional dimensions and strain rates. A large inelastic deformation of approximately 50% is obtained under both isothermal loading and adiabatic loading. With very high degree of repeatability of such pentagonal nanowire formation, the present findings indicate that the interesting stability property and high strength of elongated nanowires have various potential applications in nanomechanical and nanoelectronic devices. Further, we demonstrate a novel thermomechanical unloading mechanism by which it is possible to impart recovery from a pentagonal nanowire following a hysteresis loop: [Formula: see text].

The dynamics of polymerized carbon nanotubes in semiconductor polymer electronics and electro-mechanical sensing.

Polymerized carbon nanotubes (CNTs) are promising materials for polymer-based electronics and electro-mechanical sensors. The advantage of having a polymer nanolayer on CNTs widens the scope for functionalizing it in various ways for polymer electronic devices. However, in this paper, we show for the first time experimentally that, due to a resistive polymer layer having carbon nanoparticle inclusions and polymerized carbon nanotubes, an interesting dynamics can be exploited. We first show analytically that the relative change in the resistance of a single isolated semiconductive nanotube is directly proportional to the axial and torsional dynamic strains, when the strains are small, whereas, in polymerized CNTs, the viscoelasticity of the polymer and its effective electrical polarization give rise to nonlinear effects as a function of frequency and bias voltage. A simplified formula is derived to account for these effects and validated in the light of experimental results. CNT-polymer-based channels have been fabricated on a PZT substrate. Strain sensing performance of such a one-dimensional channel structure is reported. For a single frequency modulated sine pulse as input, which is common in elastic and acoustic wave-based diagnostics, imaging, microwave devices, energy harvesting, etc, the performance of the fabricated channel has been found to be promising.

Stress-induced phase transformation and pseudo-elastic/pseudo-plastic recovery in intermetallic Ni-Al nanowires.

Extensive molecular dynamics (MD) simulations have been performed in a B2-NiAl nanowire using an embedded atom method (EAM) potential. We show a stress induced [Formula: see text]-centered-tetragonal (BCT) phase transformation and a novel temperature and cross-section dependent pseudo-elastic/pseudo-plastic recovery from such an unstable BCT phase with a recoverable strain of approximately 30% as compared to 5-8% in polycrystalline materials. Such a temperature and cross-section dependent pseudo-elastic/pseudo-plastic strain recovery can be useful in various interesting applications of shape memory and strain sensing in nanoscale devices. Effects of size, temperature, and strain rate on the structural and mechanical properties have also been analyzed in detail. For a given size of the nanowire the yield stress of both the B2 and the BCT phases is found to decrease with increasing temperature, whereas for a given temperature and strain rate the yield stress of both the B2 and the BCT phase is found to increase with increase in the cross-sectional dimensions of the nanowire. A constant elastic modulus of approximately 80 GPa of the B2 phase is observed in the temperature range of 200-500 K for nanowires of cross-sectional dimensions in the range of 17.22-28.712 A, whereas the elastic modulus of the BCT phase shows a decreasing trend with an increase in the temperature.

Graphene Oxide-A Tool for the Preparation of Chemically Crosslinking Free Alginate-Chitosan-Collagen Scaffolds for Bone Tissue Engineering.

Developing a biodegradable scaffold remains a major challenge in bone tissue engineering. This study was aimed at developing novel alginate-chitosan-collagen (SA-CS-Col)-based composite scaffolds consisting of graphene oxide (GO) to enrich porous structures, elicited by the freeze-drying technique. To characterize porosity, water absorption, and compressive modulus, GO scaffolds (SA-CS-Col-GO) were prepared with and without Ca2+-mediated crosslinking (chemical crosslinking) and analyzed using Raman, Fourier transform infrared (FTIR), X-ray diffraction (XRD), and scanning electron microscopy techniques. The incorporation of GO into the SA-CS-Col matrix increased both crosslinking density as indicated by the reduction of crystalline peaks in the XRD patterns and polyelectrolyte ion complex as confirmed by FTIR. GO scaffolds showed increased mechanical properties which were further increased for chemically crosslinked scaffolds. All scaffolds exhibited interconnected pores of 10-250 µm range. By increasing the crosslinking density with Ca2+, a decrease in the porosity/swelling ratio was observed. Moreover, the SA-CS-Col-GO scaffold with or without chemical crosslinking was more stable as compared to SA-CS or SA-CS-Col scaffolds when placed in aqueous solution. To perform in vitro biochemical studies, mouse osteoblast cells were grown on various scaffolds and evaluated for cell proliferation by using MTT assay and mineralization and differentiation by alizarin red S staining. These measurements showed a significant increase for cells attached to the SA-CS-Col-GO scaffold compared to SA-CS or SA-CS-Col composites. However, chemical crosslinking of SA-CS-Col-GO showed no effect on the osteogenic ability of osteoblasts. These studies indicate the potential use of GO to prepare free SA-CS-Col scaffolds with preserved porous structure with elongated Col fibrils and that these composites, which are biocompatible and stable in a biological medium, could be used for application in engineering bone tissues.

Risedronate/zinc-hydroxyapatite based nanomedicine for osteoporosis.

Targeting of superior osteogenic drugs to bone is an ideal approach for treatment of osteoporosis. Here, we investigated the potential of using risedronate/zinc-hydroxyapatite (ZnHA) nanoparticles based formulation in a rat model of experimental osteoporosis. Risedronate, a targeting moiety that has a strong affinity for bone, was loaded to ZnHA nanoparticles by adsorption method. Prepared risedronate/ZnHA drug formulation was characterized by field-emission scanning electron microscopy, X-ray diffraction analysis and fourier transform infrared spectroscopy. In vivo performance of the prepared risedronate/ZnHA nanoparticles was tested in an experimental model of postmenopausal osteoporosis. Therapy with risedronate/ZnHA drug formulation prevented increase in serum levels of bone-specific alkaline phosphatase and tartrate-resistant acid phosphatase 5b better than risedronate/HA or risedronate. With respect to improvement in the mechanical strength of the femoral mid-shaft and correction of increase in urine calcium and creatinine levels, the therapy with risedronate/ZnHA drug formulation was more effective than risedronate/HA or risedronate therapy. Moreover, risedronate/ZnHA drug therapy preserved the cortical and trabecular bone microarchitecture better than risedronate/HA or risedronate therapy. Furthermore, risedronate/ZnHA drug formulation showed higher values of calcium/phosphorous ratio and zinc content. The results strongly implicate that risedronate/ZnHA drug formulation has a therapeutic advantage over risedronate or risedronate/HA therapy for the treatment of osteoporosis.

Numerical analysis of lamb wave generation in piezoelectric composite IDT.

An equivalent, single-layer model for Lamb wave generation by interdigital transducer (IDT) on composite host structures is developed. The additional complexities generally encountered while launching the surface acoustic wave (SAW) on composite structure, such as the coupling between the Lamb wave modes, the complicated nature of the electromechanical actuation etc. are considered. The model of infinite IDT is extended to deal with the finite IDT with edge discontinuities. The effect of electromechanical actuation on the wavelength shifts with respect to the passive case is investigated. The problem of electrically driven instability within the IDT is analyzed. Numerical results are reported by considering a model of the IDT integrated with the host structure, which shows that there are significant deviations from the conventional design estimates while launching a targeted mode. The proposed approach may enable one to obtain new designs in material systems and geometry that avoid mode-mixing, or to introduce it by choice.

Additive effects of zoledronic acid and propranolol on bone density and biochemical markers of bone turnover in osteopenic ovariectomized rats.

OBJECTIVES: The present study was designed to investigate further the efficacy and safety of zoledronic acid (ZOL) and propranolol (PRO) as monotherapy and combination therapy in a rat model of postmenopausal osteoporosis. METHODS: Female Wistar rats were ovariectomized (OVX) or sham-operated at 3 months of age. Twelve weeks post-surgery, rats were randomized into six groups: (1) sham + vehicle; (2) OVX + vehicle; (3) OVX + ZOL (100 µg/kg, i.v. single dose); (4) OVX + ZOL (50 µg/kg, i.v. single dose); (5) OVX + PRO (0.1 mg/kg, s.c. 5 days per week); (6) OVX + ZOL (50 µg/kg, i.v. single dose) + PRO (0.1 mg/kg, s.c. 5 days per week) for 12 weeks. After treatment, femurs were tested for bone density, porosity and trabecular micro-architecture. Biochemical markers in serum and urine were also determined. RESULTS: Combined treatment with ZOL plus PRO corrected decrease in serum calcium and increase in serum alkaline phosphatase and tartarate resistant acid phosphatase level better than single-drug therapy using ZOL or PRO. Moreover, combined treatment with ZOL plus PRO corrected increase in urine calcium, phosphorous and creatinine level better than single-drug therapy using ZOL or PRO. Combination therapy using ZOL plus PRO also preserved the trabecular micro-architecture and cortical bone porosity. CONCLUSION: These data suggest that combined treatment with ZOL plus PRO could be more effective approach for treating severe osteoporosis in humans.

[Additive effect of zoledronic acid and alfacalcidol in the treatment of disuse osteoporosis in rats]. / Efeito combinado do ácido zoledrônico e do alfacalcidol no tratamento da osteoporose por desuso em ratos.

OBJECTIVES: Disuse by bed rest, limb immobilization or space flight causes rapid bone loss. We conducted the present study to investigate the therapeutic effects of zoledronic acid (ZOL), alone and in combination with alfacalcidol (ALF) in a rat model of disuse osteoporosis. METHODS: In the present study, 3-month-old male Wistar rats had their right hind-limb immobilized (RHLI) for 10 weeks to induce osteopenia, then were divided into four groups: 1- RHLI positive control; 2- RHLI plus ZOL (50 µg/kg, i.v. single dose); 3- RHLI plus ALF (0.5 µg/kg, oral gauge daily); 4- RHLI plus ALF (0.5 µg/kg, oral gauge daily) plus ZOL (50 µg/kg, i.v. single dose) for another 10 weeks. One group of non-immobilized rats was used as negative control. At the end of the treatment, the femurs were removed and tested for bone porosity, bone mechanical properties, and bone dry and ash weight. RESULTS: Combination therapy with ZOL plus ALF was more effective in decreasing bone porosity than each drug administered as monotherapy in RHLI rats. With respect to improvement in the mechanical strength of the femoral mid-shaft, the combination treatment of ZOL plus ALF was more effective than each drug administered as a monotherapy. Moreover, combination therapy using ZOL plus ALF was more effective in improving dry bone and ash weight, than single-drug therapy using ZOL or ALF in RHLI rats. CONCLUSIONS: These data suggest that combination therapy with ZOL plus ALF represents a potentially useful therapeutic option for the treatment of disuse osteoporosis.

The combination therapy with zoledronic Acid and propranolol improves the trabecular microarchitecture and mechanical property in an rat model of postmenopausal osteoporosis.

We conducted the present study to investigate the therapeutic effects of propranolol (PRO), alone and in combination with the antiresorptive agent ZOL, in a rat model of postmenopausal osteoporosis. Female Wistar rats were OVX or sham-operated at 3 months of age. Twelve weeks after surgery, rats were randomized into six groups: (1) sham + vehicle, (2) OVX + vehicle, (3) OVX + ZOL (100 µ g/kg, i.v. single dose), (4) OVX + ZOL (50 µ g/kg, i.v. single dose), (5) OVX + PRO (0.1 mg/kg, s.c. 5 days per week), and (6) OVX + ZOL (50 µ g/kg, i.v. single dose) + PRO (0.1 mg/kg, s.c. 5 days per week) for 12 weeks. At the end of treatment study, various bone parameters were evaluated. With respect to improvement in the mechanical strength of the lumbar spine and the femoral mid-shaft, the combination treatment of ZOL and PRO was more effective than each drug administered as a monotherapy. Moreover, combination therapy using ZOL and PRO preserved the trabecular microarchitecture better than single-drug therapy using ZOL or PRO in OVX rats. These data suggest that combination therapy with ZOL plus PRO represents a potentially useful therapeutic option for patients with osteoporosis.

Evaluation of polyvinylidene fluoride nasal sensor to assess deviated nasal septum in comparision with peak nasal inspiratory flow measurements.

BACKGROUND: Deviated nasal septum (DNS) is one of the major causes of nasal obstruction. Polyvinylidene fluoride (PVDF) nasal sensor is the new technique developed to assess the nasal obstruction caused by DNS. This study evaluates the PVDF nasal sensor measurements in comparison with PEAK nasal inspiratory flow (PNIF) measurements and visual analog scale (VAS) of nasal obstruction. METHODS: Because of piezoelectric property, two PVDF nasal sensors provide output voltage signals corresponding to the right and left nostril when they are subjected to nasal airflow. The peak-to-peak amplitude of the voltage signal corresponding to nasal airflow was analyzed to assess the nasal obstruction. PVDF nasal sensor and PNIF were performed on 30 healthy subjects and 30 DNS patients. Receiver operating characteristic was used to analyze the DNS of these two methods. RESULTS: Measurements of PVDF nasal sensor strongly correlated with findings of PNIF (r = 0.67; p < 0.01) in DNS patients. A significant difference (p < 0.001) was observed between PVDF nasal sensor measurements and PNIF measurements of the DNS and the control group. A cutoff between normal and pathological of 0.51 Vp-p for PVDF nasal sensor and 120 L/min for PNIF was calculated. No significant difference in terms of sensitivity of PVDF nasal sensor and PNIF (89.7% versus 82.6%) and specificity (80.5% versus 78.8%) was calculated. CONCLUSION: The result shows that PVDF measurements closely agree with PNIF findings. Developed PVDF nasal sensor is an objective method that is simple, inexpensive, fast, and portable for determining DNS in clinical practice.

Prophylactic Effects of Propranolol versus the Standard Therapy on a New Model of Disuse Osteoporosis in Rats.

Disuse by bed rest, limb immobilization, or space flight causes rapid bone loss by arresting bone formation and accelerating bone resorption. Propranolol (a non-selective ß-adrenergic antagonist) has been shown to improve bone properties by increasing bone formation and decreasing bone resorption in an ovariectomy-induced rat model. However, no studies have yet compared the osteoprotective properties of propranolol with well-accepted therapeutic interventions for the treatment and prevention of immobilization/disuse osteoporosis. To clarify this, we investigated the effects of propranolol compared with zoledronic acid and alfacalcidol in a new animal model of immobilization/disuse osteoporosis. Three-month-old male Wistar rats were divided into five groups with six animals in each group: (1) immobilized (IMM) control; (2) normal control; (3) IMM + zoledronic acid (50 µg/kg, intravenous single dose); (4) IMM + alfacalcidol (0.5 µg/kg, per oral daily); (5) IMM + propranolol (0.1 mg/kg, subcutaneously 5 days/week) for 10 weeks. In groups 1 and 3-5, the right hindlimb was immobilized. At the end of treatment, the femurs were removed and tested for bone porosity, bone mechanical properties, and cortical microarchitecture. Treatment with propranolol induced greater reductions in the bone porosity of the right femur and improved the mechanical properties of the femoral mid-shaft femur in comparison to the IMM control. Moreover, treatment with propranolol also improved the microarchitecture of cortical bones when compared with the IMM control, as indicated by scanning electron microscopy. The anti-osteoporotic property of propranolol was comparable with zoledronic acid and alfacalcidol. This study shows that the bone resorption induced by immobilization/disuse in rats can be suppressed by treatment with propranolol.

Improvement in bone properties by using risedronate adsorbed hydroxyapatite novel nanoparticle based formulation in a rat model of osteoporosis.

A superior drug formulation capable of achieving efficient osteogenesis is in imperative demand for the treatment of osteoporosis. In the present study we investigated the potential of using novel risedronate-hydroxyapatite (HA) nanoparticle based formulation in an animal model of established osteoporosis. Nanoparticles of HA loaded with risedronate (NHLR) of various sizes (80-130 nm) were generated for bone targeted drug delivery. Three months after ovariectomy, 36 ovariectomized (OVX) rats were divided into 6 equal groups and treated with various doses of NHLR (500, 350 and 250 microg/kg intravenous single dose) and sodium risedronate (500 microg/kg, intravenous single dose). Untreated OVX and sham OVX served as controls. One month after drug administration, the left tibia and femur were tested for bone mechanical properties and histology, respectively. In the right femur, bone density was measured by method based on Archimedes principle and bone porosity analyses were performed using X-ray imaging. NHLR (250 microg/kg) showed a significant increase in bone density and reduced bone porosity when compared with OVX control. Moreover, NHLR (250 microg/kg) significantly increased bone mechanical properties and bone quality when compared with OVX control. The results strongly suggest that the NHLR, which is a novel nanoparticle based formulation, has a therapeutic advantage over risedronate sodium monotherapy for the treatment of osteoporosis in a rat model of postmenopausal osteoporosis.

Description of a new method of ovariectomy in female rats.

Rats are currently the most used laboratory animals to investigate osteoporosis. We report an efficient method of ovariectomy and compared this method with the two other operative methods of ovariectomy (i.e., midline dorsal skin incision and double dorsolateral approach, which are used commonly for inducing experimental osteoporosis. Female Wistar rats, 12 weeks old, were divided into three groups. Ovariectomy was preceded by a single midline dorsal skin incision, 3 cm long, in the group A; double dorsolateral incisions, approximately 1 cm long, in the group B; and a single ventral transverse incision of 0.4-0.6 cm at the middle abdominal region in the group C. Animals in groups A, B, and C had a mean weight of 258.12 ± 0.54 g, 255.78 ± 0.42 g, and 254.55 ± 1.69 g, respectively. There were significant differences in the duration (in minutes) of surgery in the groups B (9.65 ± 0.86) and C (7.55 ± 0.11, P < 0.001) when compared to the group A (15.52 ± 0.30) and in the group B (P < 0.01) when compared to the group C. Wound healing time (in days) for groups B (9.22 ± 0.67) and C (8.01 ± 0.93) was significantly shorter than that for group A (11.58 ± 1.2, P < 0.001), with the wound healing time for group C being slightly shorter than that for group B. The surgery, as conducted in the group C, was technically easier, less time consuming and showed less wound healing duration.

Drugs for the management of osteoporosis: a review.

Osteoporosis is characterized by low bone mass with micro architectural deterioration of bone tissue leading to enhance bone fragility, thus increasing the susceptibility to fracture. Osteoporosis is an important public health problem leading to an increased risk of developing spontaneous and traumatic fractures. In India osteoporotic fractures occur more commonly in both sexes, and may occur at a younger age than in the western countries. Although exact numbers are not available, based on available data and clinical experience, 36 million Indians may be affected by osteoporosis by 2013. This would be associated with enormous costs and considerable consumption of health resources. Pharmacological therapies that effectively reduce the number of fractures by improving bone mass are now available widely in markets. At present most drugs available in the markets decrease bone loss by inhibiting bone resorption, but the upcoming therapies may increase bone mass by directly increasing bone mass as is the case of parathyroid hormone. Current treatment alternatives include bisphosphonates, calcitonin, selective estrogen receptor modulators and inhibitors of RANK pathway but sufficient calcium and vitamin D are a prerequisite. Newer osteoclast targeted agents like cathepsin K and c-src kinase are under clinical development. The therapies which target osteoblasts include the agents acting through the Wnt-ß catenin signaling pathway like Dkk-1 inhibitors and sclerostin antagonists. To further improve pharmacological interventions and therapeutical choices in this field, improvement of knowledge is very necessary.