Topical Dexamethasone Counters Intravitreal Ivermectin-Induced Ocular Toxicity in a Rabbit Model

PURPOSE

Systemic use of Ivermectin has been reported to incite blindness in humans and veterinary patients. This study was designed to investigate the systemic and intravitreal effect of Ivermectin on ocular and retinal health and its attenuation with topical Dexamethasone.

METHODS

Systemic injection of Ivermectin@ 1.6 mg/kg S/C was administered, thrice a week for three weeks to New Zealand White rabbits (N = 4) with and without topical drops of Verapamil (N = 4). Pre and post-treatment ocular examination was conducted. At the end of three weeks the eyes were collected for histopathology.0.2 ml of Ivermectin solution (1.6 mg/ml) was injected intravitreally in one eye of the rabbit (N = 8), Half the rabbits received 0.1% dexamethasone drops thrice daily for 7 days, while the controls received PBS. Pre and post-treatment, detailed examination was conducted, which included the Schirmer Tear test, Fluorescein staining, Intraocular pressure, slit lamp biomicroscopy and fundus photography. The retina was harvested for histopathological and tunnel assay.

RESULTS

Systemic therapy with Ivermectin, with and without Verapamil did not incite any adverse response in the eye. Intravitreal Ivermectin evoked severe uveitis 4/4, cataract 3/4, corneal erosion 3/4 eyes and severe inflammatory response. Eyes that received dexamethasone were rescued from the adverse changes as demonstrated clinically, by histopathology and prevention of apoptosis.

CONCLUSIONS

Intravitreal Ivermectin incites severe inflammatory response. Topical dexamethasone counters the ocular toxicity incited by Ivermectin.

Downregulation of PTEN Promotes Autophagy via Concurrent Reduction in Apoptosis in Cardiac Hypertrophy in PPAR α−/− Mice

Cardiac hypertrophy is characterized by an increase in the size of the cardiomyocytes which is initially triggered as an adaptive response but ultimately becomes maladaptive with chronic exposure to different hypertrophic stimuli. Prolonged cardiac hypertrophy is often associated with mitochondrial dysfunctions and cardiomyocyte cell death. Peroxisome proliferator activated receptor alpha (PPAR α), which is critical for mitochondrial biogenesis and fatty acid oxidation, is down regulated in hypertrophied cardiomyocytes. Yet, the role of PPAR α in cardiomyocyte death is largely unknown. To assess the role of PPAR α in chronic hypertrophy, isoproterenol, a β-adrenergic receptor agonist was administered in PPAR α knock out (PPAR α−/−) mice for 2 weeks and hypertrophy associated changes in cardiac tissues were observed. Echocardiographic analysis ensured the development of cardiac hypertrophy and compromised hemodynamics in PPAR α−/− mice. Proteomic analysis using high resolution mass spectrometer identified about 1,200 proteins enriched in heart tissue. Proteins were classified according to biological pathway and molecular functions. We observed an unexpected down regulation of apoptotic markers, Annexin V and p53 in hypertrophied heart tissue. Further validation revealed a significant down regulation of apoptosis regulator, PTEN, along with other apoptosis markers like p53, Caspase 9 and c-PARP. The autophagy markers Atg3, Atg5, Atg7, p62, Beclin1 and LC3 A/B were up regulated in PPAR α−/− mice indicating an increase in autophagy. Similar observations were made in a high cholesterol diet fed PPAR α−/−mice. The results were further validated in vitro using NRVMs and H9C2 cell line by blocking PPAR α that resulted in enhanced autophagosome formation upon hypertrophic stimulation. The results demonstrate that in the absence of PPAR α apoptotic pathway is inhibited while autophagy is enhanced. The data suggest that PPAR α signaling might act as a molecular switch between apoptosis and autophagy thereby playing a critical role in adaptive process in cardiac hypertrophy.

Systemic deficiency of vitronectin is associated with aortic inflammation and plaque progression in ApoE‐Knockout mice

Optimal cell spreading and interplay of vascular smooth muscle cells (VSMC), inflammatory cells, and cell adhesion molecules (CAM) are critical for progressive atherosclerosis and cardiovascular complications. The role of vitronectin (VTN), a major cell attachment glycoprotein, in the pathogenesis of atherosclerosis remains elusive. In this study, we attempt to examine the pathological role of VTN in arterial plaque progression and inflammation. We found that, relative expression analysis of VTN from the liver of Apolipoprotein E (ApoE) Knockout mice revealed that atherosclerotic progression induced by feeding mice with high cholesterol diet (HCD) causes a significant downregulation of VTN mRNA as well as protein after 60 days. Promoter assay confirmed that cholesterol modulates the expression of VTN by influencing its promoter. Mimicking VTN reduction with siRNA in HCD fed ApoE Knockout mice, accelerated athero‐inflammation with an increase in NF‐kB, ICAM‐1, and VCAM‐1 at the site of the plaque along with upregulation of inflammatory proteins like MCP‐1 and IL‐1β in the plasma. Also, matrix metalloprotease (MMP)‐9 and MMP‐12 expression were increased and collagen content was decreased in the plaque, in VTN deficient condition. This might pose a challenge to plaque integrity. Human subjects with acute coronary syndrome or having risk factors of atherosclerosis have lower levels of VTN compared to healthy controls suggesting a clinical significance of plasma VTN in the pathophysiology of coronary artery disease. We establish that, VTN plays a pivotal role in cholesterol‐driven atherosclerosis and aortic inflammation and might be a useful indicator for atherosclerotic plaque burden and stability.

Mitigating fibrosis-An impediment to corneal re-innervation following lamellar flap surgery

Restoration of corneal sensitivity is of utmost importance to maintain corneal homeostasis following any injury or insult, for which, both corneal nerve regeneration and re-innervation are essential. Fibrosis poses a major impediment for re-innervation. We have in this study evaluated the influence of various nerve growth factors and corneal fibrosis on corneal nerve regeneration and reinnervation following lamellar flap surgery (LFS) and its modulation using antifibrotic drug pirfenidone. To achieve this, trigeminal ganglion cells were treated with pirfenidone, NGF, and NT-3 to evaluate their effect on trigeminal cell neurite growth. Following LFS, the gene expression of nerve growth factors NGF, BDNF and NT-3, Gap 43, Nogo-A and profibrotic factors Tenascin C, TGF-beta 1 were evaluated with and without pirfenidone. Wound fibrosis and corneal nerve regeneration using pirfenidone following LFS were evaluated by staining whole corneal mounts with α SMA and β tubulin 3. Safety of NGF and pirfenidone topical drops in normal unoperated cornea and its efficacy in enhancing corneal healing was evaluated following LFS. Our study shows, pirfenidone did not influence trigeminal cell neurite elongation; NGF and NT-3 significantly enhanced trigeminal cell neurite elongation. NT-3 also significantly increased neurite branching. There was significant increase in the gene expression of NGF, BDNF, NT-3, Gap- 43, TGF beta-1, Tenascin C, Nogo-A genes in the operated cornea compared to normal cornea, treatment of operated corneas with pirfenidone prevented the increased expression of these genes except Gap 43 which remained unchanged. The treatment of operated eyes with combination of NGF and pirfenidone positively influenced corneal healing compared to treatment with NGF alone, and had no adverse influence on the cornea. Pirfenidone appreciably reduced corneal fibrosis which aided in re-innervation. Both NGF and NT3 positively influence trigeminal neurite elongation. NGF and pirfenidone have complementary influence on corneal wound healing.

Correction to: Controlled delivery of pirfenidone through vitamin E-loaded contact lens ameliorates corneal inflammation

In the original article the typesetter made several errors. Figures 7 and 9 are incorrect. Following are the correct figures.

In vitro drug release and in vivo safety of vitamin E and cysteamine loaded contact lenses

Cystinosis is an orphan disease caused by a genetic mutation that leads to deposition of cystine crystals in many organs including cornea. Ophthalmic manifestation of the disease can be treated with hourly instillation of cysteamine eye drops. The hourly eye drop instillation is tedious to the patients leading to poor compliance and additionally, significant degradation of the drug occurs within one week of opening the bottle, which further complicates this delivery approach. This paper focuses on designing a contact lens to treat the disease with improved efficacy compared to eye drops, and also exploring safety of the drug eluding contact lens in an animal model. Our goal is to design a lens that is safe and that can deliver a daily therapeutic dose of cysteamine to the cornea while retaining drug stability. We show that cysteamine diffuses out rapidly from all lenses due to its small size. Vitamin E incorporation increases the release duration of both ACUVUE^®OASYS^® and ACUVUE^® TruEye^TM but the effect is more pronounced in TruEye^TM likely due to the low solubility of vitamin E in the lens matrix and higher aspect ratio of the barriers. The barriers are not effective in hydrogel lenses, which along with the high aspect ratio in silicone hydrogels suggests that barriers could be forming at the interface of the silicone and hydrogel phases. The presence of vitamin E has an additional beneficial effect of reduction in the oxidation rates, likely due to a transport barrier between the oxygen diffusing through the silicone channels and drug located in the hydrogel phase. Based on this study, both Acuvue^®OASYS^® and ACUVUE^® TruEye^TM can be loaded with vitamin E to design a cysteamine eluting contact lenses for effective therapy of cystinosis. The lenses must be worn for about 4-5 hr. each day, which is less than the typical duration of daily-wear. The vitamin E and cysteamine loaded lenses did not exhibit any toxicity in a rabbit model over a period of 7-days.

Intracameral Use of Nepafenac: Safety and Efficacy Study

PURPOSE

To test the intracameral safety of nepafenac and its efficacy in inhibiting prostaglandin synthesis during phacoemulsification surgery.

METHODS

The safety evaluation was conducted in normal eyes of rabbits, 0.1ml of 0.3% and 1% nepafenac was injected intracamerally. Extensive studies to detect adverse response ranged from a gross examination of eyes under slit lamp biomicroscope, fluorescein dye test, Schirmer tear test, test for corneal sensitivity, intraocular pressure measurement (IOP), specular microscopy, electroretinography(ERG), and histopathological examination of intraocular tissues. Efficacy of nepafenac was studied by intracameral injection of 0.1%, 0.3% nepafenac, nepafenac 0.3%+1% lignocaine, and 1% lignocaine alone, before phacoemulsification surgery and intraoperative mydriasis along with PGE2(ProstaglandinE2) secretion were recorded.

RESULTS

Single 0.1ml of 0.3% or 1% nepafenac did not significantly (p > 0.05) alter physiological parameters and histology of cornea, iris, and retina. Nepafenac 0.3% effectively inhibited PGE2 secretion. No significant (p > 0.05) prevention of miosis was recorded with 0.1% or 0.3% nepafenac. However, a combination of 0.3% nepafenac + 1% lignocaine and 1% lignocaine alone significantly (p < 0.05) arrested miosis during the intraoperative period.

CONCLUSION

An intracameral concentration of up to 1% nepafenac does not adversely affect the rabbit eye. Nepafenac fails to prevent miosis but inhibits prostaglandin release during phacoemulsification surgery.

Analyzing text recognition from tactually evoked EEG

Tactual exploration of objects produce specific patterns in the human brain and hence objects can be recognized by analyzing brain signals during tactile exploration. The present work aims at analyzing EEG signals online for recognition of embossed texts by tactual exploration. EEG signals are acquired from the parietal region over the somatosensory cortex of blindfolded healthy subjects while they tactually explored embossed texts, including symbols, numbers, and alphabets. Classifiers based on the principle of supervised learning are trained on the extracted EEG feature space, comprising three features, namely, adaptive autoregressive parameters, Hurst exponents, and power spectral density, to recognize the respective texts. The pre-trained classifiers are used to classify the EEG data to identify the texts online and the recognized text is displayed on the computer screen for communication. Online classifications of two, four, and six classes of embossed texts are achieved with overall average recognition rates of 76.62, 72.31, and 67.62% respectively and the computational time is less than 2 s in each case. The maximum information transfer rate and utility of the system performance over all experiments are 0.7187 and 2.0529 bits/s respectively. This work presents a study that shows the possibility to classify 3D letters using tactually evoked EEG. In future, it will help the BCI community to design stimuli for better tactile augmentation n also opens new directions of research to facilitate 3D letters for visually impaired persons. Further, 3D maps can be generated for aiding tactual BCI in teleoperation.

Pirfenidone inhibits post-traumatic proliferative vitreoretinopathy

PurposeThe purpose of the study was to evaluate the efficacy and safety of intravitreal pirfenidone for inhibition of proliferative vitreoretinopathy (PVR) in a model of penetrating ocular injury.Patients and methodsPenetrating trauma was induced on the retina of rabbit and treated either with 0.1 ml of phosphate-buffered saline (PBS) or 0.1 ml of 0.5% pirfenidone, and development of PVR was evaluated clinically and graded after 1 month. Histopathology and immunohistochemistry with transforming growth factor beta (TGFβ), alpha smooth muscle actin (αSMA), and collagen-1 were performed to assess the fibrotic changes. Expression of cytokines in the vitro-retinal tissues at different time points following pirfenidone and PBS injection was examined by RT-PCR. Availability of pirfenidone in the vitreous of rabbit at various time points was determined by high-performance liquid chromatography following injection of 0.1 ml of 0.5% pirfenidone. In normal rabbit eye, 0.1 ml of 0.5% pirfenidone was injected to evaluate any toxic effect.ResultsClinical assessment and grading revealed prevention of PVR formation in pirfenidone-treated animals, gross histology, and histopathology confirmed the observation. Immunohistochemistry showed prevention in the expression of collagen-I, αSMA, and TGFβ in the pirfenidone-treated eyes compared to the PBS-treated eyes. Pirfenidone inhibited increased gene expression of cytokines observed in control eyes. Pirfenidone could be detected up to 48 h in the vitreous of rabbit eye following single intravitreal injection. Pirfenidone did not show any adverse effect following intravitreal injection; eyes were devoid of any abnormal clinical sign, intraocular pressure, and electroretinography did not show any significant change and histology of retina remained unchanged.ConclusionThis animal study shows that pirfenidone might be a potential therapy for PVR. Further clinical study will be useful to evaluate the clinical application of pirfenidone.

Molecular cues to the anti-implantation effect of nano-puerarin in rats

Puerarin, a selective oestrogen receptor modulator, intercepts implantation in rats, albeit at unacceptably higher doses. We developed poly lactic-co-glycolic acid-encapsulated nano-puerarin (PN) and mapped the molecular pathway underlying its anti-implantation effects. Smooth-surfaced and spherical PN having a mean diameter of ∼147nm was obtained with good yield, efficient encapsulation, and optimum drug loading. In culture, PN slowly and steadily released puerarin, which was readily taken up by the decidual cells. PN exerted a dose-dependent anti-implantation effect. As marked by attenuated expression of stromal cell desmin, alkaline phosphatase, IGFBP1, and decidual prolactin-related protein, the anti-implantation effect of PN seemed secondary to compromised decidualization. Usingin vivo(pregnant and pseudopregnant rats) andin vitro(endometrial stromal cell culture) treatment models, we document that PN enforced inhibition of uterine expression ofHbegfandHoxa10and their downstream signalling molecules, Cyclin D3 (CCND3)/CDK4. PN also efficiently ablated theIhh-Nr2f2-Bmp2signalling pathway and invited the loss of uterine potential for decidualization. There was a dose-dependent up-regulation of RHOA and its effector protein kinase, ROCK1, leading to the promotion of MLC phosphorylation and actin–myosin interaction. PN also down-regulated the stromal cell activation of ERK½ and expression of MMP9. These effects acting together stabilized the stroma and inhibited the stromal cell migration. Central to this array of events was the adversely altered endometrial expression of oestrogen receptor subtypes and repression of progesterone receptor that indulged endless proliferation of luminal epithelia and distorted the precisely choreographed stroma–epithelia crosstalk. Thus, PN dismantles the endometrial bed preparation and prevents implantation.

Simultaneous inhibition of key growth pathways in melanoma cells and tumor regression by a designed bidentate constrained helical peptide

Protein-protein interactions are part of a large number of signaling networks and potential targets for drug development. However, discovering molecules that can specifically inhibit such interactions is a major challenge. S100B, a calcium-regulated protein, plays a crucial role in the proliferation of melanoma cells through protein-protein interactions. In this article, we report the design and development of a bidentate conformationally constrained peptide against dimeric S100B based on a natural tight-binding peptide, TRTK-12. The helical conformation of the peptide was constrained by the substitution of α-amino isobutyric acid--an amino acid having high helical propensity--in positions which do not interact with S100B. A branched bidentate version of the peptide was bound to S100B tightly with a dissociation constant of 8 nM. When conjugated to a cell-penetrating peptide, it caused growth inhibition and rapid apoptosis in melanoma cells. The molecule exerts antiproliferative action through simultaneous inhibition of key growth pathways, including reactivation of wild-type p53 and inhibition of Akt and STAT3 phosphorylation. The apoptosis induced by the bidentate constrained helix is caused by direct migration of p53 to mitochondria. At moderate intravenous dose, the peptide completely inhibits melanoma growth in a mouse model without any significant observable toxicity. The specificity was shown by lack of ability of a double mutant peptide to cause tumor regression at the same dose level. The methodology described here for direct protein-protein interaction inhibition may be effective for rapid development of inhibitors against relatively weak protein-protein interactions for de novo drug development.

Non-mulberry Silk Fibroin Biomaterial for Corneal Regeneration

PURPOSE

Successful repair of a damaged corneal surface is a great challenge and may require the use of a scaffold that supports cell growth and differentiation. Amniotic membrane is currently used for this purpose, in spite of its limitations. A thin transparent silk fibroin film from non-mulberry Antheraea mylitta (Am) has been developed which offers to be a promising alternative. The silk scaffolds provide sufficient rigidity for easy handling, the scaffolds support the sprouting, migration, attachment and growth of epithelial cells and keratocytes from rat corneal explants; the cells form a cell sheet, preserve their phenotypes, express cytokeratin3 and vimentin respectively. The films also support growth of limbal stem cell evidenced by expression of ABCG2. The cell growth on the silk film and the amniotic membrane is comparable. The implanted film within the rabbit cornea remains transparent, stable. The clinical examination as well as histology shows absence of any inflammatory response or neovascularization. The corneal surface integrity is maintained; tear formation, intraocular pressure and electroretinography of implanted eyes show no adverse changes. The silk fibroin film from non-mulberry silk worms may be a worthy candidate for use as a corneal scaffold.

Curcumin nanoparticles inhibit corneal neovascularization

Corneal neovascularization is a leading cause for compromised vision. Therapeutic prevention of corneal neovascularization is a major clinical challenge, and there is a compelling need to seek effective and safe therapy for this pathology. This study is aimed to evaluate curcumin nanoparticle for prevention of corneal neovascularization. MePEG-PCL nanoparticles were successfully prepared and characterized. The nanoparticle of curcumin has shown increased efficiency in preventing angiogenic sprouting in vitro. Topical delivery of curcumin nanoparticle in the eye showed enhanced retention of curcumin in the cornea, and significant improvement in prevention of corneal neovascularization over free curcumin as graded clinically and by histopathology; suppression in the expression of VEGF, inflammatory cytokines, and MMP was evidenced in the treated cornea. Curcumin inhibited NFκB in LPS-induced corneal cells. Histopathology and scanning electron microscopy showed absence of any adverse change in the corneal structure following application of curcumin nanoparticle. Therefore, we conclude that curcumin nanoparticle can be a potential candidate for prevention of corneal neovascularization.

KEY MESSAGE

• Curcumin nanoparticles show enhanced retention of curcumin in the cornea. • Curcumin NPs suppress the expression of VEGF, inflammatory cytokines, and MMP. • Curcumin NPs prevent corneal neovascularization by suppressing the NFκB pathway. • Curcumin NPs may be a promising candidate for prevention of corneal neovascularization.

A novel segmentation approach for noisy medical images using intuitionistic fuzzy divergence with neighbourhood-based membership function

Medical image segmentation demands higher segmentation accuracy especially when the images are affected by noise. This paper proposes a novel technique to segment medical images efficiently using an intuitionistic fuzzy divergence-based thresholding. A neighbourhood-based membership function is defined here. The intuitionistic fuzzy divergence-based image thresholding technique using the neighbourhood-based membership functions yield lesser degradation of segmentation performance in noisy environment. Its ability in handling noisy images has been validated. The algorithm is independent of any parameter selection. Moreover, it provides robustness to both additive and multiplicative noise. The proposed scheme has been applied on three types of medical image datasets in order to establish its novelty and generality. The performance of the proposed algorithm has been compared with other standard algorithms viz. Otsu's method, fuzzy C-means clustering, and fuzzy divergence-based thresholding with respect to (1) noise-free images and (2) ground truth images labelled by experts/clinicians. Experiments show that the proposed methodology is effective, more accurate and efficient for segmenting noisy images.

Influence of silver nanoparticles on post-surgical wound healing following topical application

Prevention of surgical site infection and wound dehiscence are imperative and also challenging in clinical practice. This study examines the healing response of laparotomy wounds following application of silver nanoparticles.

Dermal fibroblasts were exposed to incremential doses of silver nanoparticles and its effect on collagen synthesis and cytotoxicity was assessed. Laparotomy surgery was performed on rabbits and the operation site was treated topically either with silver nanoparticle once, or once daily for 14 days or with vehicle. Healing response and local tissue reaction was evaluated clinically by histopathology and scanning electron microscopy (SEM); microbial load on the operation site was assessed. Clinical tests and histopathology were performed to assess systemic toxicity.

Silver nanoparticles increased collagen expression from dermal fibroblasts and longer time exposure increased caspase 3 expression and produced cyotoxic effect with an IC50 of 0.16 mg/mL. Daily treatment of operation sites resulted in increased collagen deposition and improved wound healing, microbial load was reduced. Although a sub dermal edema was evident in histopathology, SEM showed normal architecture of cells with infiltration of lymphocytes. There was no systemic toxicity.

Silver nanoparticles exhibit a positive influence on wound healing but its effect on local tissue remains a concern.

Pirfenidone nanoparticles improve corneal wound healing and prevent scarring following alkali burn

Purpose

To evaluate the effects of pirfenidone nanoparticles on corneal re-epithelialization and scarring, major clinical challenges after alkali burn.

Methods

Effect of pirfenidone on collagen I and α-smooth muscle actin (α-SMA) synthesis by TGFβ induced primary corneal fibroblast cells was evaluated by immunoblotting and immunocytochemistry. Pirfenidone loaded poly (lactide-co-glycolide) (PLGA) nanoparticles were prepared, characterized and their cellular entry was examined in primary corneal fibroblast cells by fluorescence microscopy. Alkali burn was induced in one eye of Sprague Dawley rats followed by daily topical treatment with free pirfenidone, pirfenidone nanoparticles or vehicle. Corneal re-epithelialization was assessed daily by flourescein dye test; absence of stained area indicated complete re-epithelialization and the time for complete re-epithelialization was determined. Corneal haze was assessed daily for 7 days under slit lamp microscope and graded using a standard method. After 7 days, collagen I deposition in the superficial layer of cornea was examined by immunohistochemistry.

Results

Pirfenidone prevented (P<0.05) increase in TGF β induced collagen I and α-SMA synthesis by corneal fibroblasts in a dose dependent manner. Pirfenidone could be loaded successfully within PLGA nanoparticles, which entered the corneal fibroblasts within 5 minutes. Pirfenidone nanoparticles but not free pirfenidone significantly (P<0.05) reduced collagen I level, corneal haze and the time for corneal re-epithelialization following alkali burn.

Conclusion

Pirfenidone decreases collagen synthesis and prevents myofibroblast formation. Pirfenidone nanoparticles improve corneal wound healing and prevent fibrosis. Pirfenidone nanoparticles are of potential value in treating corneal chemical burns and other corneal fibrotic diseases.

Doxorubicin-loaded MePEG-PCL nanoparticles for prevention of posterior capsular opacification

AIMS

Cytotoxic drugs are considered as potent candidates for the prevention of posterior capsular opacification (PCO), but the toxicity incited to healthy intraocular structures is a major concern. In this study, the authors evaluated the effect of PEG methyl ether-block-poly(ε-caprolactone) (MePEG-PCL) doxorubicin (DOX)-loaded nanoparticles (NPs) for prevention of PCO and their influence on intraocular tissues.

METHODS

MePEG-PCL DOX NPs were prepared and characterized. The cytotoxic effect of DOX NPs on lens epithelial cells was compared with free drug. Its effect on PCO prevention following single subconjunctival delivery to lensectomized rabbits was assessed. Toxicity to intraocular structures was evaluated by specular microscopy, electroretinography and histopathology. The availability of DOX in aqueous humor was determined by HPLC.

RESULTS

The cytotoxic effect of DOX NPs was higher compared with free DOX due to prolonged retention within the cells. A significant reduction in degree of PCO was observed in DOX NP-treated eyes compared with untreated controls. There was no significant change in the density and morphology of corneal endothelial cells or the histology of intraocular structures. Electroretinographs of treated eyes did not change compared with the pretreatment values. DOX could be detected by HPLC in the aqueous humor up to 48 h following single subconjunctival injection.

CONCLUSION

The authors conclude that DOX-loaded MePEG-PCL NPs show promise as a new approach to selectively kill highly proliferative lens epithelial cells in vivo following cataract surgery, while sparing normal tissue.

Hydroxychavicol, a Piper betle leaf component, induces apoptosis of CML cells through mitochondrial reactive oxygen species-dependent JNK and endothelial nitric oxide synthase activation and overrides imatinib resistance

Alcoholic extract of Piper betle (Piper betle L.) leaves was recently found to induce apoptosis of CML cells expressing wild type and mutated Bcr-Abl with imatinib resistance phenotype. Hydroxy-chavicol (HCH), a constituent of the alcoholic extract of Piper betle leaves, was evaluated for anti-CML activity. Here, we report that HCH and its analogues induce killing of primary cells in CML patients and leukemic cell lines expressing wild type and mutated Bcr-Abl, including the T315I mutation, with minimal toxicity to normal human peripheral blood mononuclear cells. HCH causes early but transient increase of mitochondria-derived reactive oxygen species. Reactive oxygen species-dependent persistent activation of JNK leads to an increase in endothelial nitric oxide synthase-mediated nitric oxide generation. This causes loss of mitochondrial membrane potential, release of cytochrome c from mitochondria, cleavage of caspase 9, 3 and poly-adenosine diphosphate-ribose polymerase leading to apoptosis. One HCH analogue was also effective in vivo in SCID mice against grafts expressing the T315I mutation, although to a lesser extent than grafts expressing wild type Bcr-Abl, without showing significant bodyweight loss. Our data describe the role of JNK-dependent endothelial nitric oxide synthase-mediated nitric oxide for anti-CML activity of HCH and this molecule merits further testing in pre-clinical and clinical settings.

Involvement of ROS in chlorogenic acid-induced apoptosis of Bcr-Abl+ CML cells

Chlorogenic acid (Chl) has been reported to possess a wide range of biological and pharmacological properties including induction of apoptosis of Bcr-Abl(+) chronic myeloid leukemia (CML) cell lines and clinical leukemia samples via inhibition of Bcr-Abl phosphorylation. Here we studied the mechanisms of action of Chl in greater detail. Chl treatment induced an early accumulation of intracellular reactive oxygen species (ROS) in Bcr-Abl(+) cells leading to downregulation of Bcr-Abl phosphorylation and apoptosis. Chl treatment upregulated death receptor DR5 and induced loss of mitochondrial membrane potential accompanied by release of cytochrome c from the mitochondria to the cytosol. Pharmacological inhibition of caspase-8 partially inhibited apoptosis, whereas caspase-9 and pan-caspase inhibitor almost completely blocked the killing. Knocking down DR5 using siRNA completely attenuated Chl-induced caspase-8 cleavage but partially inhibited apoptosis. Antioxidant NAC attenuated Chl-induced oxidative stress-mediated inhibition of Bcr-Abl phosphorylation, DR5 upregulation, caspase activation and CML cell death. Our data suggested the involvement of parallel death pathways that converged in mitochondria. The role of ROS in Chl-induced death was confirmed with primary leukemia cells from CML patients in vitro as well as in vivo in nude mice bearing K562 xenografts. Collectively, our results establish the role of ROS for Chl-mediated preferential killing of Bcr-Abl(+) cells.

Influence of topical anesthetics on oculocardiac reflex and corneal healing in rabbits

AIM

To investigate the incidence of oculocardiac reflex (OCR) with two anesthetic regimens and its prevention using topical anesthetics in a rabbit model, and to explore the effect of topical anesthetics on corneal healing.

METHODS

Forty-eight clinically healthy adult New Zealand white rabbits of either sex were divided into two groups (Group A and B) and anesthetized with either ketamine (Group A, n =24) or propofol (Group B, n =24). he incidence of OCR was recorded in each group with a variety of ocular manipulation with or without the use of topical anesthetics (40g/L lignocaine, 5g/L proparacain, 5g/L bupivacaine). Corneal toxicity and healing following the use of each topical anesthetic was assessed one day after surgery and up to 7 days postoperatively by clinical examination of the eye, histopathology and collagen staining and transmission electron microscopy.

RESULTS

No incidence of OCR was recorded with ocular manipulation under ketamine anesthesia, whereas significant reduction in heart rate (P<0.01) was recorded under propofol anesthesia. Topical anesthetics could successfully prevent the OCR without affecting the corneal healing.

CONCLUSION

Topical anesthetics may be recommended for prevention of OCR without any local adverse effect.

Sarcoma-like mural nodules in ovarian mucinous cystadenomas--a report of two cases

Sarcoma-like mural nodule is a very rare occurrence in a mucinous tumour of the ovary. Two such nodules having morphologically benign features with osteoclastic giant cells, in the wall of mucinous cystadenoma are described. In addition, these nodules exhibited reactive vascular proliferations. The sarcoma-like nodules are associated with a favourable outcome and must be distinguished from other malignant nodules composed of sarcoma or anaplastic carcinoma that may also occur in the wall of mucinous ovarian tumours.

Sarcoma-like mural nodules in ovarian mucinous cystadenomas--a report of two cases

Sarcoma-like mural nodule is a very rare occurrence in a mucinous tumour of the ovary. Two such nodules having morphologically benign features with osteoclastic giant cells, in the wall of mucinous cystadenoma are described. In addition, these nodules exhibited reactive vascular proliferations. The sarcoma-like nodules are associated with a favourable outcome and must be distinguished from other malignant nodules composed of sarcoma or anaplastic carcinoma that may also occur in the wall of mucinous ovarian tumours.

Differential expression of procollagen lysine 2-oxoglutarate 5-deoxygenase and matrix metalloproteinase isoforms in hypothyroid rat ovary and disintegration of extracellular matrix

Hypothyroid-induced reproductive malfunction in both the sexes is a common phenomenon of global concern. In an attempt to characterize the differentially expressed genes that might be responsible for these disorders, we have identified a number of clones in hypothyroid rat ovary by subtractive hybridization. One such clone is procollagen lysyl hydroxylase2 (Plod-2), the key enzyme for the first step of collagen biosynthetic pathway, which was down-regulated in hypothyroid condition. We have also demonstrated the reduced expression of other isoforms of Plods, namely Plod-1 and -3 in hypothyroid rat ovary. The current studies are the first of their kind to report that thyroid hormone regulates the Plod gene in rat ovary. Moreover, we have shown the up-regulation of matrix-degrading enzyme(s), matrix metalloproteinase(s) in the hypothyroid rat ovary, whereas the tissue-inhibitory metalloproteinase is down-regulated. Finally, the results of the present studies indicate that in hypothyroid condition, collagen biosynthesis in ovary seems to be disturbed with concomitant enhancement in collagen degradation, resulting in disintegration of overall ovarian structure.

Analysis of differentially expressed genes in hyperthyroid-induced hypertrophied heart by cDNA microarray

Experiments were carried out to identify the altered genes in hyperthyroid rat heart and their influence on the functions of cardiac myocytes. Chronic treatment of rats with 3,5,3' triiodo-L-thyronine (T3) resulted in a prominent increase in the size of the left ventricle with increased wall thickness and reduced chamber volume leading to concentric cardiac hypertrophy. The heart weight to body weight ratio (HW/BW) in hyperthyroid rats was increased by about 58% over that of normal rats. Using cDNA microarray comprising 588 genes, we compared the differences in mRNA expression of hyperthyroid and normal rat heart. Based on a threshold of greater than 10% change, about 37 genes were found to be regulated by T3. Further analyses by Western blotting, Northern blotting and real-time quantitative RT-PCR of some of the genes confirmed the microarray results. The T3-altered genes encode various types of proteins related to metabolism, matrix and cytoskeletal structures, growth factors, transcription factors, Ca(2+)-channels etc. The physiological significance of one of these altered proteins in hyperthyroid heart, insulin-responsive glucose transporter (GLUT) type 4 (GLUT4), was studied in detail. The expression of GLUT4 was drastically reduced in the ventricular tissues of hyperthyroid heart. Insulin-induced glucose uptake in hyperthyroid cardiomyocytes was reduced significantly, indicating the impaired glucose transport in cardiac cells. Interestingly, a few genes such as GLUT4, cytochrome P450 isoforms, superoxide dismutase (SOD), collagens, matrix metalloproteinases (MMP), tissue inhibitors of matrix metalloproteinases etc. which had not been reported earlier were found to be altered in hyperthyroid heart. Our results show some new aspects of hyperthyroid heart which will be important in assessing the pathophysiology of hypertrophied cardiomyocytes.

Chlorogenic acid inhibits Bcr-Abl tyrosine kinase and triggers p38 mitogen-activated protein kinase-dependent apoptosis in chronic myelogenous leukemic cells

We report that chlorogenic acid (Chl) induces apoptosis of several Bcr-Abl-positive chronic myelogenous leukemia (CML) cell lines and primary cells from CML patients in vitro and destroys Bcr-Abl-positive K562 cells in vivo. In contrast, this compound has no effect on the growth and viability of Bcr-Abl-negative lymphocytic and myeloid cell lines and primary CML cells. Sodium chlorogenate (NaChl) exhibits 2-fold higher efficiency in killing K562 cells compared with Chl. NaChl also induces growth inhibition of squamous cell carcinoma (HSC-2) and salivary gland tumor cells (HSG), although at 50-fold higher concentration. NaChl inhibits autophosphorylation of p210(Bcr-Abl) fusion protein rapidly. We demonstrate that p38 phosphorylation is increased in Bcr-Abl-positive cells after treatment with NaChl and closely paralleled the inhibition of Bcr-Abl phosphorylation. NaChl did not increase phosphorylation of p38 in Bcr-Abl-negative cells including HSC-2 and HSG that are responsive to this compound, indicating that p38 activation by NaChl is dependent on Bcr-Abl kinase inhibition. Inhibition of p38 activity by SB203580 significantly reduced NaChl-induced apoptosis of K562 cells, whereas activation of p38 by anisomycin augmented the apoptosis. These findings indicate that inhibition of Bcr-Abl kinase leading to activation of p38 mitogen-activated protein (MAP) kinase may play an important role in the anti-CML activity of Chl.

Transcatheter therapy of intravisceral bleeding

Intravisceral bleeding is a life-threatening situation demanding fast and active steps to control, unless it stops spontaneously as in a few lucky patients. A surgical approach is a major intervention with its associated procedural risks when the site is in organs other than the spleen. The transcatheter approach helps in precise location and embolization of the bleeding site; it is a more practical approach that has been known for the past 2 decades to be effective and provide good long-term results. However, the transcatheter approach has been reported in fewer than 200 cases in the literature. Our small series of 43 cases shows initial success of 95% and a fatal early recurrence of only 2.4%. Non-hemorrhagic etiology (sepsis, head injury, etc.) was the major cause of early death (14.6%) among the successfully embolized cases. Long-term follow-up shows recurrence (4.8%) only in the group of chronic etiology. Transcatheter embolization of intravisceral bleeding with Gel-Foam and/or poly-vinyl alcohol particles is a swift, effective and precise method of treatment without major operational hazards.

Response to low-dose interferon in chronic liver disease due to hepatitis B virus infection

BACKGROUND

Interferon is at present the only effective therapy for chronic hepatitis B virus (HBV) infection. Data regarding its efficacy in India are scant. The present study was undertaken to assess the efficacy of low-dose interferon in chronic liver disease due to HBV infection.

METHODS

Twenty four patients with histologic evidence of chronic hepatitis with or without cirrhosis, and persistent elevation of serum aminotransferases and persistent positivity for HBsAg and HBeAg for more than six months, were included. Fourteen patients were treated with interferon alpha-2b, 3 million units thrice weekly for 16 weeks; ten patients who could not afford the drug were followed up as controls without specific therapy. Patients were examined weekly for the first 4 weeks, followed by two weekly for 12 weeks and then every two months. Blood tests for viral markers and liver biochemistry were done at 0, 4, 8, 12, 16 weeks and then at two-month intervals for at least one year after therapy. Patients who cleared HBeAg were followed up for 2.2 (1-4) years for HBsAg clearance.

RESULTS

HBeAg clearance occurred in 9 patients (64%) in the interferon group, and in one control patient (p < 0.01). HBsAg clearance occurred in only one patient in the treatment group during follow up of mean 2.4 years. No patient in the control group cleared HBsAg. Patients having high ALT level at the beginning of treatment had significantly higher HBeAg clearance rate (7 of 7) than patients with low ALT levels (2 of 7; p < 0.05).

CONCLUSION

Low-dose interferon therapy is effective in attaining HBeAg, but not HBsAg, clearance in chronic HBV infection.

Natural history of severe duodenal ulcer disease

BACKGROUND

A subset of patients with chronic duodenal ulcer has severe ulcer diathesis in the form of frequent relapses and complications like perforation and hemorrhage. We observed the effect of drug treatment on the natural history of this subset.

METHODS

Of 526 patients diagnosed to have chronic duodenal ulcer by endoscopy, 23 patients with severe diathesis were available for long follow-up (mean period 36 months). Each patient was assessed clinically and endoscopically every 2 months for at least 12 months and then every 3 months or when symptomatic. Helicobacter pylori status was assessed during endoscopy. The effect of antisecretory drugs and anti-H. pylori therapy on natural history was determined.

RESULTS

Thirteen of 23 patients (56%) had refractory ulcers; six responded to double dose of H2-receptor antagonists (H2RA) for 8 weeks and six to omeprazole 40 mg daily for 4-8 weeks. Of 20 patients (87%) who were H. pylori-positive, 15 completed triple-drug therapy; of these, 10 patients eradicated H. pylori. These 10 patients were followed up for 24 months; there were no ulcer relapses within the first 12 months but 8 of them relapsed between 12 and 24 months (total number of relapses 8). Reinfection with H. pylori occurred in 3 patients. In the other 10 patients who remained H. pylori-positive, there were 19 episodes of ulcer relapse in 7 patients over 24 months, in spite of maintenance therapy with H2RA (p < 0.05).

CONCLUSIONS

Refractoriness in patients with severe ulcer disease is usually episodic and amenable to larger doses of omeprazole or H2RA. Anti-H. pylori therapy improves the natural history but its effect in preventing ulcer relapse is short lasting (less than 12 months). Recurrence of infection is a problem in our population.

Cognitive reasoning using fuzzy neural nets

The paper presents a new model for cognitive reasoning using fuzzy neural nets. The analysis of the proposed model yields guaranteed stability of the temporal fuzzy inferences, derived from the network and conditional stability of the structure of the cognitive map, framed by the arcs of the network. The results arrived at in the paper have been illustrated with reference to a typical weather forecast system.

Collision tumor of gastrointestinal tract

A rare combination of multiple adenomatous polyps of the colon and carcinoid tumor of the ileum in a 54-year-old man is reported.

Fate of [14C]coumaphos after dermal application to lactating goats as a pour-on formulation

Two lactating Nubian goats were dermally treated with [14C]coumaphos (O-[3-chloro-4-methyl-2-oxo-2H-benzopyran-7-yl] O,O-diethyl phosphorothioate) as a 4% active ingredient pour-on formulation. Doses were administered, along the dorsal midline from withers to sacrum, at a rate equivalent to 14 mg of coumaphos/kg of body weight. During the 7 days after treatment, an average of less than 0.1, 4.7, and 1% of the administered dose was eliminated in the milk, urine, and feces, respectively. When goats were killed after 7 days, about 45% of the administered radiocarbon remained on the hair and skin, and this consisted almost entirely of intact coumaphos. Residues in selected tissues collected after 7 days were, in every case, less than 1 mg of coumaphos equivalent/kg of tissue, with highest residues in adipose tissue, followed by residues in kidney and liver. In milk, residue amounts plateaued after about 2 days and remained relatively constant at about 0.1 mg of coumaphos equivalent/kg of milk. Residues in adipose tissue and in milk consisted mainly of unmetabolized coumaphos. In urine, most radiocarbon was present as metabolites of coumaphos, but in feces, most radiocarbon was present as the intact parent compound. Coumaphos was absorbed slowly and at a constant rate after dermal application to lactating goats as a pour-on formulation.

Protein losing enteropathy as a sole manifestation of non-Hodgkin's lymphoma

We describe a patient who presented with oedema and hypoproteinaemia which was proved to be due to protein-losing enteropathy. Extensive gastrointestinal investigations failed to discover any definitive cause. He subsequently developed tuberculous inguinal lymphadenopathy but although treated for tuberculosis the protein-losing state persisted. Later on he developed renal failure due to obstructive nephropathy. Laparotomy was carried out and it disclosed the diagnosis of non-Hodgkin's lymphoma, treatment of which cured the protein-losing state.