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Khurana S, Biswal M, Bhatti HS, Pandav SS, Gupta A, Chatterjee SS, Lyngdoh WV, Malla N. Ophthalmomyiasis: Three cases from north India. Indian J Med Microbiol 2010; 28:257-61. [DOI: 10.4103/0255-0857.66490] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Bhattacharya S, Khurana S, Bhatti HS, Singhi S, Malla N. Polyparasitism: Fasciolopsis buski, Ascaris lumbricoides and discussion Hookworm coinfection in a child. TROPICAL GASTROENTEROLOGY : OFFICIAL JOURNAL OF THE DIGESTIVE DISEASES FOUNDATION 2010; 31:126-127. [PMID: 20862994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
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78
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Khurana S, Bedi P, Jain N. Development of nanostructured lipid carriers (NLC) for controlled delivery of meloxicam. ACTA ACUST UNITED AC 2010. [DOI: 10.1504/ijbnn.2010.034654] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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79
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Kaul V, Khurana S, Munoz S. Management of medication noncompliance in solid-organ transplant recipients. BioDrugs 2009; 13:313-26. [PMID: 18034538 DOI: 10.2165/00063030-200013050-00002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Solid-organ transplantation has emerged as one of the most significant medical advances in the management of end-stage organ disease to date. However, a long term successful outcome after transplantation relies heavily upon the extended, if not lifelong, intake of immunosuppressive medication. Noncompliance with the medication regimen may have devastating effects on the graft and the patient. Furthermore, the effects of noncompliance place an additional burden on the medical resources available and the already scarce organ supply. The magnitude of post-transplant noncompliance and factors associated with noncompliance with various immunosuppressant drugs are reviewed. Patient, physician, social and family relationships interact in a complex manner in the post-transplant scenario and problems here could underlie noncompliance. The paper also includes a review of the methods of evaluating and monitoring noncompliance. Preventive and remedial measures that may help the transplant team to effectively manage this problem are suggested. The multidisciplinary nature of post-transplant patient management and the need for a cohesive approach toward the patient is emphasised. With the identification of patients at higher risk for noncompliance, close monitoring and early intervention, it may be possible to effectively control the effects of noncompliance until newer strategies are developed which permit immunosuppression-free transplantation.
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Khurana S, Norris PJ, Busch MP, Mlisana K, Salim AK, Hunter E, Golding H. P14-04. HIV-SELECTEST EIA and rapid test: a novel assay for differential diagnosis of HIV infections in the face of vaccine-generated antibodies. Retrovirology 2009. [PMCID: PMC2767684 DOI: 10.1186/1742-4690-6-s3-p192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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81
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Khurana S, Utreja P, Tiwary A, Jain N, Jain S. Nanostructured Lipid Carriers and their application in drug delivery. INTERNATIONAL JOURNAL OF BIOMEDICAL ENGINEERING AND TECHNOLOGY 2009. [DOI: 10.1504/ijbet.2009.022913] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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82
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Paul T, Li S, Khurana S, Leleiko N, Walsh M. The epigenetic signature of CFTR expression is co-ordinated via chromatin acetylation through a complex intronic element. Biochem J 2008; 408:317-26. [PMID: 17848139 PMCID: PMC2267364 DOI: 10.1042/bj20070282] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The CFTR (cystic fibrosis transmembrane conductance regulator) gene is a tightly regulated and differentially expressed transcript in many mucosal epithelial cell types. It appears that DNA sequence variations alone do not explain CFTR-related gastrointestinal disease patterns and that epigenetic modifiers influence CFTR expression. Our aim was to characterize the native chromatin environment in cultured cells for intestinal CFTR expression by determining the relationship between histone acetylation and occupation of CFTR by multiple transcription factors, through a common regulatory element. We used HDAC (histone deacetylase) inhibition and ChIP (chromatin immunoprecipitation) analyses to define regions associated with acute acetylation of histone at the CFTR locus. We identified a region within the first intron associated with acute acetylation of histone H4 as an epigenetic signature corresponding to an intestine-specific enhancer element for CFTR. DHS (DNase I-hypersensitivity) assays and ChIP were used to specify control elements and occupation by regulatory factors. Quantitative ChIP procedures indicate that HNF1alpha (hepatic nuclear factor 1alpha) and Cdx2 (caudal homeobox protein 2) occupy and regulate through a novel intronic enhancer element of CFTR and that Tcf4 (T-cell factor 4) overlaps the same DNA element. RNAi (RNA interference) of Tcf4 and HNF1alpha decreased intestinal cell CFTR expression, identifying these as positive regulatory factors and CFTR as a target for Wnt signalling. We have linked the acetylation signature of nucleosomal histones to active intestinal CFTR expression and occupation by transcription factors HNF1alpha, Cdx2 and Tcf4 which converge to modify chromatin architecture. These studies suggest the therapeutic potential of histone modification strategies, such as inhibition of HDAC activity, to treat CFTR-associated disease by selectively enhancing CFTR expression.
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Khurana S, Orford J, Preen D, Logan J, Gera P, Jackson C. SE13 ACCURACY, ACCEPTANCE AND COMPLIANCE IN THE USE OF A WEB BASED AUDIT TOOL ? RESULTS OF PHASE 1. ANZ J Surg 2007. [DOI: 10.1111/j.1445-2197.2007.04129_13.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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84
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Ang JP, Heath JA, Donath S, Khurana S, Auldist A. Treatment outcomes for hepatoblastoma: an institution's experience over two decades. Pediatr Surg Int 2007; 23:103-9. [PMID: 17119981 DOI: 10.1007/s00383-006-1834-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2006] [Accepted: 10/16/2006] [Indexed: 01/26/2023]
Abstract
Our objective is to review a leading Australian tertiary referral centre's experience in treating hepatoblastoma over two decades. This is a retrospective study of clinical, radiological and pathological data in hepatoblastoma patients treated at our institution between 1984 and 2004. Thirty children (17 male, 13 female) ranging in age from 5 months to 6.5 years (median 19 months) at diagnosis were reviewed. This is the largest case series reported in Australia to date. The median length of follow-up was 6.3 years (range 7 months to 20.9 years). On average, the number of new cases increased by 0.12 each year (P=0.01). A total of 29 patients underwent definitive surgery for primary tumour control. Of these, two (7%) had initial primary surgery, while 27 (93%) had delayed surgery following neo-adjuvant chemotherapy. Chemotherapy regimens included the SIOPEL study protocols. Patients not enrolled in SIOPEL tended to be given more courses of chemotherapy. Ten patients (34%) received an extended right hemi-hepatectomy, six (21%) had right hemi-hepatectomy, seven (24%) had left hemi-hepatectomy, three (10%) had left lateral segmentectomy, and two (7%) had a non-anatomical resection. In addition, two patients required IVC reconstruction at the time of their primary liver resection. Overall survival at 5 years was 89.1% (95% CI 69.8-96.4%). Event-free survival at 5 years was 75.7% (95% CI 53.2-88.5%). There was a clear increase in the risk of recurrence (RR=4.8) and death (RR=4.5) where margins were not microscopically clear. However, neither reached statistical significance in this small cohort. Surgery was still worthwhile even when margins were involved. There was no correlation between mean AFP level at diagnosis, and outcome. Our experience suggests that the achievement of microscopically clear margins at the time of primary tumour resection is an important factor in achieving a positive long-term outcome. In addition, extended courses of neo-adjuvant chemotherapy in patients with pulmonary metastases achieves good long-term outcomes, provided adequate surgical resection of the primary tumour with clear microscopic margins can be achieved.
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Ohrn A, Blomgren J, Park H, Khurana S, Nolte R, Schmidt D, Wilhelmsen K. A monitor for neutron flux measurements up to 20 MeV. RADIATION PROTECTION DOSIMETRY 2007; 126:394-7. [PMID: 17496304 DOI: 10.1093/rpd/ncm081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
A liquid scintillation detector aimed for neutron energy and fluence measurements in the energy region <20 MeV has been calibrated using monoenergetic and white spectrum neutron fields. Careful measurements of the proton light output function and the response matrix have been performed allowing for the application of unfolding techniques using existing codes. The response matrix is used to characterise monoenergetic neutron fields produced by the T(d,n) at a low-energy deuteron accelerator installed at the Swedish Defense Research Agency (FOI).
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Bhadury J, Khurana S, Peng H, Zong H. Optimization Modeling in Acquisitions: A Case Study from the Motor Carrier Industry. JOURNAL OF SUPPLY CHAIN MANAGEMENT 2006. [DOI: 10.1111/j.1745-493x.2006.00021.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
Recent advances in the fields of molecular biology, epidemiology and infectious diseases have led to significant revelations to clarify the relationship between cancer and infective agents. This article reviews the relationship between parasitic infections and carcinogenesis and the possible mechanisms involved. Few parasites, e.g., Schistosoma haematobium and Opisthorchis viverrini have been found to be strongly associated with bladder cancer and cholangiocarcinoma respectively. The evidence for the association of several other parasites and cancers has also been postulated.
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Malhotra S, Rana SV, Sinha SK, Khurana S. Dietary fiber assessment of patients with irritable bowel syndrome from Northern India. Indian J Gastroenterol 2005; 23:217-8. [PMID: 15627661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Data on the absolute fiber intake and the source of dietary fiber intake in patients with irritable bowel syndrome (IBS) have been lacking in northern Indians. OBJECTIVE To find out the absolute fiber intake from different sources of food items in patients with IBS and healthy subjects from northern India. METHODS Using the 72-hour recall method, dietary intake of macronutrients and fiber was determined in 33 consecutive adult patients with IBS and 33 age- and gender-matched healthy controls. RESULTS The patients consumed lower amounts of macronutrients (protein 60.4 g vs 79.3 g, fat 47.7 g vs 65.7 g, and carbohydrates 294.6 g vs 339.8 g) and dietary fiber (8.1 g vs 15.7 g) than the control subjects. Though the patients consumed similar amount of pulses as the controls (46.6 [25.0] vs 46 [19.6] g/day), their fiber intake from pulses was lower (0.8 [0.7] vs 1.4 [0.9] g/day). The intake of fiber from vegetables and fruits was also significantly lower in patients (2.1 and 0.5 g/day, respectively) than in control subjects (5.8 and 3.9 g/day, respectively; p< 0.001 each). CONCLUSION Total dietary fiber intake and intake of fiber from vegetables, fruits and pulses are lower in patients with IBS from northern India than in control subjects.
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Batra V, Musani AI, Hastie AT, Khurana S, Carpenter KA, Zangrilli JG, Peters SP. Bronchoalveolar lavage fluid concentrations of transforming growth factor (TGF)-beta1, TGF-beta2, interleukin (IL)-4 and IL-13 after segmental allergen challenge and their effects on alpha-smooth muscle actin and collagen III synthesis by primary human lung fibroblasts. Clin Exp Allergy 2004; 34:437-44. [PMID: 15005738 DOI: 10.1111/j.1365-2222.2004.01885.x] [Citation(s) in RCA: 145] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
RATIONALE Asthmatic airway remodelling is characterized by myofibroblast hyperplasia and subbasement membrane collagen deposition. We hypothesized that cytokines and growth factors implicated in asthmatic airway remodelling are increased in bronchoalveolar lavage (BAL) fluid of asthmatics after segmental allergen challenge (SAC), and that these growth factors and cytokines increase alpha-smooth muscle actin (alpha-SMA) and collagen III synthesis by human lung fibroblasts (HLFs). METHODS Transforming growth factor (TGF)-beta1, TGF-beta2, IL-4 and IL-13 levels were measured in BAL fluid from 10 asthmatics and 9 non-asthmatic controls at baseline and then 1 day, 1 week and 2 weeks after SAC. Confluent cultures of HLFs were stimulated by exogenous addition of TGF-beta1, TGF-beta2, IL-4 or IL-13 (concentration range 0.01-10 ng/mL) over 48 h. Collagen III was measured in culture supernates and alpha-SMA in cell lysates by Western blot. RESULTS At baseline, there was no difference in BAL fluid concentrations of TGF-beta1, IL-4 and IL-13 between asthmatics and controls; however, non-asthmatics had higher concentrations of total TGF-beta2. In asthmatics, BAL fluid concentrations of all four factors increased significantly 1 day after SAC. TGF-beta1, TGF-beta2 and IL-13 concentrations returned to baseline by 1 week after SAC, but BAL fluid IL-4 concentration remained elevated for at least 2 weeks. TGF-beta1, TGF-beta2 and IL-4 significantly increased alpha-SMA in fibroblasts, but only IL-4 caused corresponding increases in collagen III synthesis. IL-13 had no direct effects on collagen III synthesis and alpha-SMA expression. CONCLUSIONS Because IL-4 caused a dose-dependent increase in alpha-SMA and collagen III synthesis, it may be an important cytokine mediating asthmatic airway remodelling. TGF-beta1 and TGF-beta2 may also play a role in airway remodelling by stimulating phenotypic change of fibroblasts to myofibroblasts. Additionally, collagen III synthesis appears to be independent of myofibroblast phenotype and is apparently regulated by different growth factors and cytokines.
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91
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Khurana S, Batra V, Patkar AA, Leone FT. Twenty-first century tobacco use: it is not just a risk factor anymore. Respir Med 2003; 97:295-301. [PMID: 12693789 DOI: 10.1053/rmed.2002.1443] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Despite availability of effective treatments for nicotine addiction, smoking remains prevalent with serious health consequences. Most smokers recognize the ill effects of smoking but are unable to quit. Nicotine addiction may be viewed as any other chronic illness that results from exposure to a recognizable agent (tobacco) and manifests with a well-documented set of signs and symptoms. Much like any chronic disease, both environmental and genetic factors determine the occurrence and severity of this affliction. There has been recent focus on uncovering the genetic basis of nicotine addiction. In this article, we have attempted to briefly review the current evidence for the role of genetics in smoking as well as comment on available pharmacotherapeutic options for treating nicotine dependence.
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92
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Khurana S, Corbally MT, Manning F, Armenise T, Kierce B, Kilty C. Glutathione S-transferase: a potential new marker of intestinal ischemia. J Pediatr Surg 2002; 37:1543-8. [PMID: 12407536 DOI: 10.1053/jpsu.2002.36181] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND/PURPOSE The accurate and early diagnosis of intestinal ischemia remains difficult chiefly because of a lack of a suitable marker that is noninvasive and easy to use. The glutathione S-transferases (GST) are a family of cytosolic enzymes involved in detoxification and released from a variety of cells when the cell membrane is damaged. The enzymes are distributed widely in the intestine and show isoform specificity in their distribution throughout the intestinal tract. Several previous reports have shown the utility of these enzymes in the diagnosis of liver and renal graft damage during and after organ transplantation. The object of this study was to determine if GST levels correlated with histologic changes of intestinal ischemia in a controlled animal model of mesenteric intestinal ischemia. METHODS Control and experimental male Sprague-Dawley rats underwent laparotomy and ligation of the Superior Mesenteric Artery (SMA) and both control and experimental animals were studied at 30, 60, 90, 120, and 240 minutes. Blood taken from the Inferior Vena Cava (IVC) and Portal Vein (PV) and jejunal and ileal perfusates were assayed for alpha and mu isoforms of GST using a commercially available enzyme immunoassay. In addition, jejunal and ileal segments were sampled and reviewed by a histopathologist blinded to the group being studied. RESULTS A reproducible pattern of intestinal ischemia was noted with worsening grades of injury observed with greater ligation times. Luminal alpha and mu GST release (as measured by the appearance in luminal perfusate) increased with increasing ischemia times. Increased ischemia times resulted in increased levels of alpha and mu GST in both portal and systemic venous samples but lagged behind the appearance of raised luminal GST values. CONCLUSIONS The results suggest that GST may be an interesting and useful marker in the early detection of intestinal ischemia. Its detection in peripheral blood has implications for a more detailed study design to determine the sensitivity and specificity of this marker in more diverse clinical conditions such as necrotizing enterocolitis and superior mesenteric artery occlusion.
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Abstract
PURPOSE The laparoscopic approach to the complete excision of urachal abnormalities in adults has recently been advocated by some groups but little has been reported in the pediatric literature. We highlight the need for the complete removal of symptomatic urachal remnants as well as the feasibility of the laparoscopic approach in children. MATERIALS AND METHODS Four children 5 months, 4, 8 and 10 years old, respectively, who presented with complicated urachal disease underwent laparoscopic resection of urachal remnants. We describe the manner of presentation and surgical technique in these 4 cases. RESULTS Laparoscopic radical excision was successfully performed in all 4 cases with an uneventful convalescence. CONCLUSIONS Our experience suggests that laparoscopic excision of urachal remnants can be safely and satisfactorily performed in children of all ages.
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Abstract
PURPOSE The laparoscopic approach to the complete excision of urachal abnormalities in adults has recently been advocated by some groups but little has been reported in the pediatric literature. We highlight the need for the complete removal of symptomatic urachal remnants as well as the feasibility of the laparoscopic approach in children. MATERIALS AND METHODS Four children 5 months, 4, 8 and 10 years old, respectively, who presented with complicated urachal disease underwent laparoscopic resection of urachal remnants. We describe the manner of presentation and surgical technique in these 4 cases. RESULTS Laparoscopic radical excision was successfully performed in all 4 cases with an uneventful convalescence. CONCLUSIONS Our experience suggests that laparoscopic excision of urachal remnants can be safely and satisfactorily performed in children of all ages.
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Khurana S, Minocha YC, Minocha KB, Dogra A. Evaluation on azathioprine in the treatment of parthenium dermatitis. Indian J Dermatol Venereol Leprol 2001; 67:309-11. [PMID: 17664785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Parthenium dermatitis is one of the most intractable problems in dermatology, the management of which poses a therapeutic challenge. The mainstay of treatment has been systemic corticosteroids for prolonged periods which may result in various side-effects.ln the present study, 30 patients of parthenium dermatitis were treated with oral azathioprine in a dose of 1-3 mg/kg/day. Assessment was done at monthly intervals using a clinical score. Azathioprine emerged as an effective and safe corticosteroid sparing agent in the treatment of parthenium dermatitis, provided the patients are carefully monitored for the side effects.
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96
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Thellin O, Noel G, Khurana S, Ogle CK, Horseman ND. Stress hormone secretion and gut signal transducer (STAT) proteins after burn injury in rats. Shock 2001; 16:393-7. [PMID: 11699080 DOI: 10.1097/00024382-200116050-00013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
A burn injury triggers traumatic reactions characteristics of a stress. Here we investigated the early responses of prolactin (PRL), corticosterone (CS), and signal transducer and activator of transcription 5 (STAT5) in male Sprague-Dawley rats after burn injury. PRL and CS levels were determined in blood serum. STAT5 and phospho-STAT5 levels were determined in jejunum total protein extracts. The results confirmed an expected increase of CS between 4 and 6 h after the burn injury. Unexpectedly, PRL secretion was suppressed during the same time frame. These hormone levels returned to normal 6 to 8 h after burn injury. STAT5 was increased in the jejunum after burn injury, and its phosphorylation was increased between 8 and 11 h after burn injury. These changes in STAT5 were not temporally correlated with either the hormone changes that we observed or with previously documented changes of the gut function after burns.
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Zhai L, Zhao P, Panebra A, Guerrerio AL, Khurana S. Tyrosine phosphorylation of villin regulates the organization of the actin cytoskeleton. J Biol Chem 2001; 276:36163-7. [PMID: 11500485 DOI: 10.1074/jbc.c100418200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have previously shown that tyrosine phosphorylation of the actin-regulatory protein villin is accompanied by the redistribution of phosphorylated villin and a concomitant decrease in the F-actin content of intestinal epithelial cells. The temporal and spatial correlation of these two events suggested that tyrosine phosphorylation of villin may be involved in the rearrangement of the microvillar cytoskeleton. This hypothesis was investigated by analyzing the effects of tyrosine phosphorylation of villin on the kinetics of actin polymerization by reconstituting in vitro the tyrosine phosphorylation of villin and its association with actin. Full-length recombinant human villin was phosphorylated in vitro by expression in the TKX1-competent cells that carry an inducible tyrosine kinase gene. The actin-binding properties of villin were examined using a co-sedimentation assay. Phosphorylation of villin did not change the stoichiometry (1:2) but decreased the binding affinity (4.4 microm for unphosphorylated versus 0.6 microm for phosphorylated) of villin for actin. Using a pyrene-actin-based fluorescence assay, we demonstrated that tyrosine phosphorylation had a negative effect on actin nucleation by villin. In contrast, tyrosine phosphorylation enhanced actin severing by villin. Electron microscopic analysis showed complementary morphological changes. Phosphorylation inhibited the actin bundling and enhanced the actin severing functions of villin. Taken together our data show that tyrosine phosphorylation of villin decreases the amount of villin bound to actin filaments, inhibits the actin-polymerizing properties of villin, and promotes the actin-depolymerizing functions instead. These observations suggest a role for tyrosine phosphorylation in modulating the microvillar cytoskeleton in vivo by villin in response to specific physiological stimuli.
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Panebra A, Ma SX, Zhai LW, Wang XT, Rhee SG, Khurana S. Regulation of phospholipase C-gamma(1) by the actin-regulatory protein villin. Am J Physiol Cell Physiol 2001; 281:C1046-58. [PMID: 11502583 DOI: 10.1152/ajpcell.2001.281.3.c1046] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The actin-regulatory protein villin is tyrosine phosphorylated and associates with phospholipase C-gamma(1) (PLC-gamma(1)) in the brush border of intestinal epithelial cells. To study the mechanism of villin-associated PLC-gamma(1) activation, we reconstituted in vitro the tyrosine phosphorylation of villin and its association with PLC-gamma(1). Recombinant villin was phosphorylated in vitro by the nonreceptor tyrosine kinase c-src or by expression in the TKX1 competent cells that carry an inducible tyrosine kinase gene. Using in vitro binding assays, we demonstrated that tyrosine-phosphorylated villin associates with the COOH-terminal Src homology 2 (SH2) domain of PLC-gamma(1). The catalytic activity of PLC-gamma(1) was inhibited by villin in a dose-dependent manner with half-maximal inhibition at a concentration of 12.4 microM. Villin inhibited PLC-gamma(1) activity by sequestering the substrate phosphatidylinositol 4,5-bisphosphate (PIP(2)), since increasing concentrations of PIP(2) reversed the inhibitory effects of villin on PLC activity. The inhibition of PLC-gamma(1) activity by villin was reversed by the tyrosine phosphorylation of villin. Further, we demonstrated that tyrosine phosphorylation of villin abolished villin's ability to associate with PIP(2). In conclusion, tyrosine-phosphorylated villin associates with the COOH-terminal SH2 domain of PLC-gamma(1) and activates PLC-gamma(1) catalytic activity. Villin regulates PLC-gamma(1) activity by modifying its own ability to bind PIP(2). This study provides biochemical proof of the functional relevance of tyrosine phosphorylation of villin and identifies the molecular mechanisms involved in the activation of PLC-gamma(1) by villin.
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Dogra A, Bajwa GS, Bajwa N, Khurana S. Alkaptonuria. Indian J Dermatol Venereol Leprol 2001; 67:271-2. [PMID: 17664775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
A case of alkaptonuria, a rare autosomal recessive metabolic disorder is being reported. The patient presented with passage of dark coloured urine, cutaneous and scleral pigmentation and joint pains. The diagnosis was confirmed by the detection of homogentisic acid in the urine.
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Verma V, Khurana S, Ram S, Greval RS. Incidence of anaerobes in throat infections and their sensitivity pattern in Ludhiana. INDIAN JOURNAL OF MEDICAL SCIENCES 2001; 55:371-5. [PMID: 11883336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Of 175 throat swabs processed, anaerobes were isolated from 16 (9.14%) patients. Isolation of anaerobes from healthy controls was 2 out of 25 (8%). Peptostreptococci and Bacteroides species were the commonest isolates followed by Peptococci and Propioni-bacterium. All of these isolates were sensitive to Metronidazole. Clindamycin, Erythromycin and Tetracycline also showed good response.
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