Browsing by Author "Shiva Kant"

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Antitumor and chemosensitizing action of dichloroacetate implicates modulation of tumor microenvironment: A role of reorganized glucose metabolism, cell survival regulation and macrophage differentiation
(2013) Ajay Kumar; Shiva Kant; Sukh Mahendra Singh
Targeting of tumor metabolism is emerging as a novel therapeutic strategy against cancer. Dichloroacetate (DCA), an inhibitor of pyruvate dehydrogenase kinase (PDK), has been shown to exert a potent tumoricidal action against a variety of tumor cells. The main mode of its antineoplastic action implicates a shift of glycolysis to oxidative metabolism of glucose, leading to generation of cytotoxic reactive oxygen intermediates. However, the effect of DCA on tumor microenvironment, which in turn regulates tumor cell survival; remains speculative to a large extent. It is also unclear if DCA can exert any modulatory effect on the process of hematopoiesis, which is in a compromised state in tumor-bearing hosts undergoing chemotherapy. In view of these lacunas, the present study was undertaken to investigate the so far unexplored aspects with respect to the molecular mechanisms of DCA-dependent tumor growth retardation and chemosensitization. BALB/c mice were transplanted with Dalton's lymphoma (DL) cells, a T cell lymphoma of spontaneous origin, followed by administration of DCA with or without cisplatin. DCA-dependent tumor regression and chemosensitization to cisplatin was found to be associated with altered repertoire of key cell survival regulatory molecules, modulated glucose metabolism, accompanying reconstituted tumor microenvironment with respect to pH homeostasis, cytokine balance and alternatively activated TAM. Moreover, DCA administration also led to an alteration in the MDR phenotype of tumor cells and myelopoietic differentiation of macrophages. The findings of this study shed a new light with respect to some of the novel mechanisms underlying the antitumor action of DCA and thus may have immense clinical applications.© 2013 Elsevier Inc.
Bicarbonate transport inhibitor SITS modulates pH homeostasis triggering apoptosis of Dalton’s lymphoma: implication of novel molecular mechanisms
(Kluwer Academic Publishers, 2014) Shiva Kant; Ajay Kumar; Sukh Mahendra Singh
Bicarbonate transporter (BCT) plays a crucial role in maintaining pH homeostasis of tumor cells by import of HCO3- This helps the tumor cells in manifesting extracellular tumor acidosis, accompanied by a relative intracellular alkalinization, which in turn promotes tumor progression. Therefore, blocking BCT-mediated HCO3- transport is envisaged as a promising anticancer therapeutic approach. Thus, using a murine model of a T cell lymphoma, designated as Dalton’s lymphoma (DL), in the present in vitro investigation the antitumor consequences of blocking BCT function by its inhibitor 4-acetamido-4-isothiocyanostilbene-2,2-disulfonate (SITS) were explored. Treatment of DL cells with SITS resulted in an increase in the extracellular pH, associated with a decline in DL cell survival and augmented induction of apoptosis. BCT inhibition also elevated the expression of cytochrome c, caspase-9, caspase-3, Bax, reactive oxygen species, and nitric oxide along with inhibition of HSP-70 and Bcl2, which regulate tumor cell survival and apoptosis. SITS-treated DL cells displayed upregulated production of IFN-γ and IL-6 along with a decline of IL-10. Treatment of DL cells with SITS also inhibited the expression of fatty acid synthase, which is crucial for membrane biogenesis in neoplastic cells. The expression of lactate transporter MCT-1 and multidrug resistance regulating protein MRP-1 got inhibited along with hampered uptake of glucose and lactate production in SITS-treated DL cells. Thus, the declined tumor cell survival following inhibition of BCT could be the consequence of interplay of several inter-connected regulatory molecular events. The outcome of this study indicates the potential of BCT inhibition as a novel therapeutic approach for treatment of hematological malignancies. © 2014, Springer Science+Business Media New York.
Converting CO2into heterocyclic compounds under accelerated performance through Fe3O4-grafted ionic liquid catalysts
(Royal Society of Chemistry, 2022) Niraj K. Vishwakarma; Shikha Singh; Sambhav Vishwakarma; Ajay Kumar Sahi; Vijay Kumar Patel; Shiva Kant; Sanjeev Kumar Mahto
Solid supported catalysts such as amines are in high demand for the chemical fixation of CO2 into commodity chemicals. Here, we demonstrate an accelerated platform for 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)-ionic liquid (IL) catalyzed CO2 fixation via the grafting of DBU-ILs over magnetically separable Fe3O4 nanoparticles (MNPs). The DBU-ILs were covalently immobilized over Fe3O4 MNPs utilizing the thio-ene reaction of allyl-DBU with -SH modified Fe3O4 MNPs. The DBU-IL-grafted Fe3O4 (Fe3O4@DBU-ILs) materials were characterized by Fourier-transform infrared (FT-IR) spectroscopy, field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA) and vibrating-sample magnetometry (VSM). TEM revealed that the MNPs have a spherical structure with a particle size of 12-20 nm. VSM showed the gradual decrease in magnetization after stepwise grafting from Fe3O4 to Fe3O4@DBU-ILs. The efficacy of the two different Fe3O4@DBU-ILs, Fe3O4@[HDBU+][TFE-] and Fe3O4@[HDBU+][AcO-] prepared by neutralization of Fe3O4@DBU with 2,2,2-trifluoroethanol (TFE) and acetic acid (AcOH), was investigated by simultaneous fixation of CO2 into the important heterocyclic compounds quinazoline-2,4(1H,3H)-dione and benzimidazolone. This approach shows excellent recyclability with a nominal decrease (2-3%) in product yields after each cycle. In particular, the energy-dispersive X-ray spectroscopy (EDX) mapping of Fe3O4@[HDBU+][TFE-] used for five cycles demonstrated significant leaching of TFE. Interestingly, after retreatment with TFE, Fe3O4@[HDBU+][TFE-] showed a similar yield to that of a fresh catalyst. This journal is © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
Crystallization, thermal, phase diagram and microstructural studies of organic analog of metal-nonmetal monotectic alloy: 4-Bromochlorobenzene-succinonitrile
(2009) R.S.B. Reddi; Shiva Kant; U.S. Rai; R.N. Rai
The phase equilibrium data on an organic analog of a metal-nonmetal system involving 4-bromochlorobenzene-succinonitrile show the formation of a eutectic and a monotectic with a large miscibility gap containing 0.96 and 0.03 mole fractions of succinonitrile, respectively, with the consolute temperature of 180.0 °C. The heat of mixing, entropy of fusion, roughness parameter, interfacial energy and excess thermodynamic functions were calculated from the enthalpy of fusion values, determined by the DSC method using TA Instruments DSC-2010. The effects of solid-liquid interfacial energy on morphological change of monotectic have also been discussed. The microstructures of monotectic and eutectic show the lamellar growth characteristic. © 2009 Elsevier B.V. All rights reserved.
Fatty acid synthase inhibitor orlistat induces apoptosis in T cell lymphoma: Role of cell survival regulatory molecules
(2012) Shiva Kant; Ajay Kumar; Sukh Mahendra Singh
Background: De novo fatty acid synthesis catalyzed by fatty acid synthase (FASN) is crucial for tumor cell survival. Thus therapeutic targeting of FASN is considered as a novel antineoplastic strategy. However, little is understood in this respect regarding malignancies of hematological origin. The present investigation was therefore, undertaken to study the molecular mechanisms of the antitumor action of FASN inhibitor orlistat (tetrahydrolipstatin) using a murine model of a T cell lymphoma. Methods: The antitumor efficacy of orlistat was investigated in vitro by estimating cell survival by MTT assay and apoptosis by Wright Giemsa, TUNEL, Annexin-V/PI staining and % DNA fragmentation. Generation of reactive oxygen species (ROS) in tumor cells was studied using fluorescence microscopy. Expression of genes and proteins was carried out by RT-PCR and western blot analyses respectively. FASN and CPT-1 activity was estimated by spectrophotometer. Cytokines expression was analyzed by ELISA. Results: We report that inhibition of FASN with its specific inhibitor orlistat manifests tumor-specific inhibition of cell survival, accompanied by induction of apoptosis. Orlistat-treated tumor cells showed an altered ROS generation, shift in cytokine balance and modulated expression of cell survival regulatory molecules like HSP70, Bcl2, p53, PUMA, Caspase-3 and CAD. It was observed that IFN-γ mediates orlistat-dependent modulation of FASN expression. Conclusion and general significance: In this study, we report some of the so far unexplored novel aspects underlying the molecular mechanisms associated with orlistat-dependent modulation of tumor cell survival. These observations will help in designing antineoplastic therapeutic protocols using orlistat against malignancies of hematological origin. © 2012 Elsevier B.V.
Myelopoietic efficacy of orlistat in murine hosts bearing T cell lymphoma: Implication in macrophage differentiation and activation
(2013) Shiva Kant; Ajay Kumar; Sukh Mahendra Singh
Orlistat, an inhibitor of fatty acid synthase (FASN), acts as an antitumor agent by blocking de novo fatty acid synthesis of tumor cells. Although, myelopoiesis also depends on de novo fatty acid synthesis, the effect of orlistat on differentiation of macrophages, which play a central role in host's antitumor defence, remains unexplored in a tumor-bearing host. Therefore, the present investigation was undertaken to examine the effect of orlistat administration on macrophage differentiation in a T cell lymphoma bearing host. Administration of orlistat (240 mg/kg/day/mice) to tumor-bearing mice resulted in a decline of tumor load accompanied by an augmentation of bone marrow cellularity and survival of bone marrow cells (BMC). The expression of apoptosis regulatory caspase-3, Bax and Bcl2 was modulated in the BMC of orlistat-administered tumor-bearing mice. Orlistat administration also resulted in an increase in serum level of IFN-γ along with decreased TGF-β and IL-10. BMC of orlistat-administered tumor-bearing mice showed augmented differentiation into macrophages accompanied by enhanced expression of macrophage colony stimulating factor (M-CSF) and its receptor (M-CSFR). The macrophages differentiated from BMC of orlistat-administered mice showed characteristic features of M 1 macrophage phenotype confirmed by expression of CD11c, TLR-2, generation of reactive oxygen species, phagocytosis, tumor cell cytotoxicity, production of IL-1,TNF-α and nitric oxide. These novel findings indicate that orlistat could be useful to support myelopoesis in a tumor-bearing host. © 2013 Kant et al.
Myelopotentiating effect of curcumin in tumor-bearing host: Role of bone marrow resident macrophages
(2012) Naveen Kumar Vishvakarma; Anjani Kumar; Ajay Kumar; Shiva Kant; Alok Chandra Bharti; Sukh Mahendra Singh
The present investigation was undertaken to study if curcumin, which is recognized for its potential as an antineoplastic and immunopotentiating agent, can also influence the process of myelopoiesis in a tumor-bearing host. Administration of curcumin to tumor-bearing host augmented count of bone marrow cell (BMC) accompanied by an up-regulated BMC survival and a declined induction of apoptosis. Curcumin administration modulated expression of cell survival regulatory molecules: Bcl2, p53, caspase-activated DNase (CAD) and p53-upregulated modulator of apoptosis (PUMA) along with enhanced expression of genes of receptors for M-CSF and GM-CSF in BMC. The BMC harvested from curcumin-administered hosts showed an up-regulated colony forming ability with predominant differentiation into bone marrow-derived macrophages (BMDM), responsive for activation to tumoricidal state. The number of F4/80 positive bone marrow resident macrophages (BMM), showing an augmented expression of M-CSF, was also augmented in the bone marrow of curcumin-administered host. In vitro reconstitution experiments indicated that only BMM of curcumin-administered hosts, but not in vitro curcumin-exposed BMM, augmented BMC survival. It suggests that curcumin-dependent modulation of BMM is of indirect nature. Such prosurvival action of curcumin is associated with altered T H1/T H2 cytokine balance in serum. Augmented level of serum-borne IFN-γ was found to mediate modulation of BMM to produce enhanced amount of monokines (IL-1, IL-6, TNF-α), which are suggested to augment the BMC survival. Taken together the present investigation indicates that curcumin can potentiate myelopoiesis in a tumor-bearing host, which may have implications in its therapeutic utility. © 2012 Elsevier Inc..
Novel molecular mechanisms of antitumor action of dichloroacetate against T cell lymphoma: Implication of altered glucose metabolism, pH homeostasis and cell survival regulation
(2012) Ajay Kumar; Shiva Kant; Sukh Mahendra Singh
Pyruvate dehydrogenase kinase (PDK) inhibits pyruvate dehydrogenase (PDH) activity and thus promotes energetic switch from mitochondrial glucose oxidation to cytoplasmic glycolysis in cancerous cells (a phenomenon known as the 'Warburg effect') for their energy need, which facilitates the cancer progression by resisting induction of apoptosis and promoting tumor metastasis. Thus, in the present investigation, we explored the molecular mechanisms of the tumoricidal action of dichloroacetate (DCA), a pyruvate dehydrogenase kinase inhibitor, on cells of a murine T cell lymphoma, designated as Dalton's lymphoma (DL). In vitro treatment of tumor cells with DCA inhibited their survival accompanied by a modulation of the biophysical composition of tumor-conditioned medium with respect to pH, glucose and lactate. DCA treatment also altered expression of HIF1-α and pH regulators: VATPase and MCT1 and production of cytokines: IL-10, IL-6 and IFN-γ. Moreover, we also observed an alteration in the expression of other apoptosis and cell survival regulatory molecules: PUMA, GLUT1, Bcl2, p53, CAD, caspase-3 and HSP70. The study discusses the role of novel molecular mechanisms underlying DCA-dependent inhibition of tumor cell survival. This study shows for the first time that DCA-dependent alteration of tumor cell survival involves altered pH homeostasis and glucose metabolism. Thus, these findings will provide a new insight for therapeutic applications of DCA as a novel antineoplastic agent against T cell lymphoma. © 2012 Elsevier Ireland Ltd. All rights reserved.
Solid state synthesis, crystal growth and optical properties of urea and p-chloronitrobenzene solid solution
(Academic Press Inc., 2016) R.N. Rai; Shiva Kant; R.S.B. Reddi; S. Ganesamoorthy; P.K. Gupta
Urea is an attractive material for frequency conversion of high power lasers to UV (for wavelength down to 190 nm), but its usage is hindered due to its hygroscopic nature, though there is no alternative organic NLO crystal which could be transparent up to 190 nm. The hygroscopic character of urea has been modified by making the solid solution (UCNB) of urea (U) and p-chloronitrobenzene (CNB). The formation of the solid solution of CNB in U is explained on the basis of phase diagram, powder XRD, FTIR, elemental analysis and single crystal XRD studies. The solubility of U, CNB and UCNB in ethanol solution is evaluated at different temperatures. Transparent single crystals of UCNB are grown from its saturated solution in ethanol. Optical properties e.g., second harmonic generation (SHG), refractive index and the band gap for UCNB crystal were measured and their values were compared with the parent compounds. Besides modification in hygroscopic nature, UCNB has also shown the higher SHG signal and mechanical hardness in comparison to urea crystal. © 2015 Published by Elsevier Inc.
Solid-liquid equilibrium and thermochemical studies of organic analogue of metal-nonmetal system: Succinonitrile-pentachloronitrobenzene
(2011) Shiva Kant; R.N. Rai
The phase diagram of an organic analogue of a metal-nonmetal system, involving succinonitrile-pentachloronitrobenzene, shows the formation of a eutectic and a monotectic. The two immiscible liquid phases are in equilibrium with a single liquid phase and the consolute temperature being 53.5 °C above the monotectic horizontal. The phase equilibrium study confirms the alloy composition of monotectic and eutectic at 0.150 and 0.985 mol fractions of succinonitrile, respectively. The solidification behaviour shows the validity of Hilling-Turnbull equation. The thermal properties such as heat of mixing, entropy of fusion, roughness parameter, interfacial energy, grain boundary energy and excess thermodynamic functions for parent components, monotectic and eutectic have been studied using their enthalpy of fusion values. The effects of solid-liquid interfacial energy on morphological change of monotectic have also been discussed. The microstructure of monotectic shows the lamellar growth along with droplets, however, eutectic infers the vertical growth of lamella. © 2010 Elsevier B.V. All rights reserved.
Solid-liquid equilibrium, thermal, crystallization and microstructural studies of organic monotectic alloy
(2010) Shiva Kant; R.S.B. Reddi; R.N. Rai
A monotectic and a eutectic organic alloy have been synthesized with the help of phase diagram study. The phase diagram of an organic analogue of a metal-nonmetal system involving succinonitrile-1,4-diiodobenzene shows two immiscible liquid phases are in equilibrium with a single liquid phase. Growth behaviour of the eutectic, the monotectic and the pure components, studied at different undercooling temperatures, suggests that the data obey the square relationship between growth velocity and undercoolings. The thermal study such as heat of mixing, entropy of fusion, roughness parameter, interfacial energy and excess thermodynamic functions were calculated via the enthalpy of fusion values, determined using differential scanning calorimeter (DSC) method. The effects of solid-liquid interfacial energy on morphology of monotectic have also been discussed. The microstructures of monotectic, eutectic and pure components show their peculiar characteristic features. © 2010 Elsevier B.V. All rights reserved.
Synthesis, physicochemical and optical characterization of novel fluorescing complex: O-phenylenediamine-benzoin
(2011) Y. Dwivedi; Shiva Kant; S.B. Rai; R.N. Rai
The complex of o-phenylenediamine (o-PDA) and benzoin (BN) was synthesized adopting solid state reaction by mixing of their melt together followed by chilling. The phase diagram study shows the formation of a complex in 1:1 molar ratio with congruent melting point and two eutectics lying on either side of complex. The formation of complex was confirmed using the FTIR, NMR, mass spectroscopy, powder XRD and DSC studies. The optical properties of the parent component, their complex and few other compositions nearby the complex were studied using absorption and laser luminescence techniques. The significantly higher green/yellow emission was noted with newly synthesized complex as compared to that of their parents as well as other compositions of o- PDA and BN. © Springer Science+Business Media, LLC 2011.
Targeting monocarboxylate transporter by α-cyano-4-hydroxycinnamate modulates apoptosis and cisplatin resistance of Colo205 cells: Implication of altered cell survival regulation
(2013) Ajay Kumar; Shiva Kant; Sukh Mahendra Singh
The present investigation was undertaken to study the effect of in vitro exposure of Colo205, colonadenocarcinoma cells, to monocarboxylate transporter inhibitor α-cyano-4-hydroxycinnamate (αCHC) on cell survival and evolution of resistance to chemotherapeutic drug cisplatin. αCHC-treated Colo205 cells showed inhibition of survival accompanied by an augmented induction of apoptosis. Changes in cell survival properties were associated with alterations in lactate efflux, pH homeostasis, expression of glucose transporters, glucose uptake, HIF-1α, generation of nitric oxide, expression pattern of some key cell survival regulatory molecules: Bcl2, Bax, active caspase-3 and p53. Pretreatment of Colo205 cells with αCHC also altered their susceptibility to the cytotoxicity of cisplatin accompanied by altered expression of multidrug resistance regulating MDR1 and MRP1 genes. This study for the first time deciphers some of the key molecular events underlying modulation of cell survival of cancer cells of colorectal origin by αCHC and its contribution to chemosensitization against cisplatin. Thus these findings will be of immense help in further research for optimizing the use of αCHC for improving the chemotherapeutic efficacy of anticancer drugs like cisplatin. © 2013 Springer Science+Business Media New York.
Thermal and physico-chemical studies on binary organic eutectic systems 4-Aminoacetophenone with benzoin and 4-nitrophenol
(2012) Shiva Kant; U.S. Rai; R.N. Rai
The phase diagrams of binary systems of 4-Aminoacetophenone (AAP) with each of benzoin (BN) and 4-nitrophenol (PNP) have been established by the thaw-melt method. This study shows the formation of eutectics. Accurate compositions of BN and PNP to form eutectic mixtures have been determined by the phase diagram study between BN-AAP and PNP-AAP in the entire range of compositions. The thermal properties of the eutectics, such as enthalpy of mixing, solid-liquid interfacial energy, entropy of fusion and excess thermodynamic functions were computed based on enthalpy of fusion values. The influence of undercooling on growth kinetics of pure components and their eutectics has been studied. The microstructural studies infer the influence of solid-liquid interfacial energy on the morphology of microstructures of eutectics. © Akademiai Kiado, Budapest, Hungary 2012.
Thermal, physicochemical and microstructural studies of organic analog of nonmetal-nonmetal monotectic alloy
(2010) K.P. Sharma; R.S.B. Reddi; Shiva Kant; R.N. Rai
The phase equilibrium of an organic analogue of a nonmetal-nonmetal system, involving resorcinol (R)-1,4-diiodobenzene (DIB), was established which shows solid is in equilibrium with liquid as well as two immiscible liquid phases are also in equilibrium with a liquid of single phase. The phase diagram study infers the formation of a monotectic and a eutectic at 0.05 and 0.97 mole fractions of resorcinol, respectively. Using X-ray diffraction technique, the range of solid solubility of R in DIB and DIB in R was studied. The thermal properties of materials such as heat of mixing, entropy of fusion, roughness parameter, interfacial energy and excess thermodynamic functions were computed from the enthalpy of fusion values, determined using differential scanning calorimeter (DSC) method. The solid-liquid interfacial energy shows the applicability of non-wetting condition. The effect of solid-liquid interfacial energy on morphological change of monotectic growth has also been discussed. The microstructures of monotectic, eutectic and pure components were taken and have shown their peculiar characteristic features. © 2009 Elsevier B.V. All rights reserved.
Tumor growth retardation and chemosensitizing action of fatty acid synthase inhibitor orlistat on T cell lymphoma: Implication of reconstituted tumor microenvironment and multidrug resistance phenotype
(2014) Shiva Kant; Ajay Kumar; Sukh Mahendra Singh
Background Orlistat, a fatty acid synthase (FASN) inhibitor, has been demonstrated to inhibit tumor cell survival. However, the mechanism(s) of its tumor growth retarding action against malignancies of hematological origin remains unclear. It is also not understood if the antitumor action of orlistat implicates modulated susceptibility of tumor cell to anticancer drugs. Therefore, the present investigation focuses to study the antitumor and chemosensitizing action of orlistat in a murine host bearing a progressively growing T cell lymphoma. Methods Tumor-bearing mice were administered with vehicle alone or containing orlistat followed by administration of PBS with or without cisplatin. Tumor progression and survival of tumor-bearing host were monitored along with analysis of tumor cell survival and apoptosis. Tumor ascitic fluid was examined for pH, NO and cytokines. Expression of genes and proteins was investigated by RT-PCR and western blot respectively. ROS was analyzed by DCFDA staining and FASN activity by spectrophotometry. Results Orlistat administration to tumor-bearing mice resulted in tumor growth retardation, prolonged life span, declined tumor cell survival and chemosensitization to cisplatin. It was accompanied by increased osmotic fragility, modulated acidosis, expression of ROS, NO, cytokines, MCT-1 and VH+ ATPase, Bcl2, Caspase-3, P53, inhibited FASN activity and declined expression of MDR and MRP-1 proteins. Conclusion Orlistat manifests antitumor and chemosensitizing action implicating modulated regulation of cell survival, reconstituted-tumor microenvironment and altered MDR phenotype. General significance These observations indicate that orlistat could be utilized as an adjunct regimen for improving antitumor efficacy of cisplatin. © 2013 Elsevier B.V.
α-Cyano-4-hydroxycinnamate induces apoptosis in Dalton's lymphoma cells: Role of altered cell survival-regulatory mechanisms
(2013) Ajay Kumar; Shiva Kant; Sukh Mahendra Singh
In the present investigation, we explored the molecular mechanisms of the tumoricidal action of α-cyano-4-hydroxycinnamate (αCHC) on the cells of Dalton's lymphoma (DL), which is a murine T cell lymphoma. In-vitro treatment of the DL cells with αCHC resulted in the modulation of the biophysical parameters of the tumor cell culture medium with respect to pH, nitric oxide, glucose, and lactate, accompanied by an alteration in the expression of cytokines (IL-10, IL-6, and IFN-γ) and cell survival-regulatory proteins such as Bcl2, p53, caspase-3, caspase-activated DNase, HSP70, and IL2R. The expression of the pH-regulatory proteins vacuolar ATPase and MCT1 was also found to be altered. The study discusses the possible role of the aforementioned alterations triggered by αCHC in the induction of tumor cell apoptosis and decreased cell survival. These findings will provide a new insight into the novel molecular mechanisms of the antitumor action of αCHC. © 2013 Wolters Kluwer Health Lippincott Williams & Wilkins.