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Carragee EJ, Tanner CM, Khurana S, Hayward C, Welsh J, Date E, Truong T, Rossi M, Hagle C. The rates of false-positive lumbar discography in select patients without low back symptoms. Spine (Phila Pa 1976) 2000; 25:1373-80; discussion 1381. [PMID: 10828919 DOI: 10.1097/00007632-200006010-00009] [Citation(s) in RCA: 239] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Experimental disc injections in subjects with no history of low back symptoms. OBJECTIVE To determine in an experimental setting the relative pain response and pain-related behavior in selected subjects without a history of low back pain undergoing lumbar discography. This study aimed to select a study population that more closely represented patients undergoing discography in clinical practice. SUMMARY OF BACKGROUND DATA Previous work has shown that in young, healthy men with little degenerative disc disease and no history of low back problems, discographic injections usually did not cause significant pain. This group differed from the patients who usually undergo discographic evaluation in clinical practice. Most clinical patients are older, have significant degenerative disc disease, have behavioral changes associated with chronic pain, and often have confounding psychosocial troubles. The authors undertook to study discography in subjects without low back pain but with clinical profiles similar to patients undergoing discography in clinical practice. METHODS Twenty-six individuals, mean age 43 years, with no history of low back pain had lumber discography according to the strict protocol of Walsh et al. Of these, 10 were pain-free; 10 had chronic neck and arm pain, but no low back symptoms; and 6 had primary somatization disorders without low back symptoms.- RESULTS Significant positive pain response and pain-related behavior with discography were found in 10% of the pain-free group, in 40% of the chronic cervical pain group, and in 83% of the somatization disorder group completing the injections. Twenty-four subjects had negative control discs. Discs with annular disruption were more likely to be painful on injection, particularly in those individuals with ongoing compensation issues, chronic pain, or abnormal psychological testing.- CONCLUSION If strict criteria are applied, the rate of false-positive discography may be low in subjects with normal psychometric profiles and without chronic pain. Significantly painful injections were very common in subjects with annular disruption and chronic pain or abnormal psychometric testing.
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Mousa SA, Khurana S, Forsythe MS. Comparative in vitro efficacy of different platelet glycoprotein IIb/IIIa antagonists on platelet-mediated clot strength induced by tissue factor with use of thromboelastography: differentiation among glycoprotein IIb/IIIa antagonists. Arterioscler Thromb Vasc Biol 2000; 20:1162-7. [PMID: 10764688 DOI: 10.1161/01.atv.20.4.1162] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In the present study, the in vitro efficacy of different platelet glycoprotein IIb/IIIa (GPIIb/IIIa) antagonists on platelet-fibrin-mediated clot strength under shear was compared with the antiaggregatory efficacy by using tissue factor (TF) thromboelastography (TEG). The ability of platelets to augment the elastic properties of blood clots under shear conditions was measured by computerized TEG under conditions of maximal platelet activation accelerated by recombinant TF. Under these conditions, platelets significantly enhance clot strength 8-fold (relative to platelet-free fibrin clots). This effect was inhibited to a different extent by various platelet GPIIb/IIIa receptor antagonists; this inhibition appears to be dependent on the transmission of platelet contractile force to fibrin via the GPIIb/IIIa receptors. The GPIIb/IIIa antagonists with high binding affinity for resting and activated platelets and slow platelet dissociation rates (class I) but not those with fast platelet dissociation rates (class II) demonstrated potent and comparable inhibition of platelet aggregation and TF-TEG clot strength. Platelet GPIIb/IIIa antagonists of class I, such as XV459 (free-acid form of roxifiban), DMP802, XV454, and c7E3, demonstrated comparable inhibitory dose responses of TF-TEG clot strength and platelet aggregation, with an IC(50) of 50 to 70 nmol/L. In contrast, platelet GPIIb/IIIa antagonists from class II, with comparable antiaggregatory efficacy, such as DMP728, YZ202 (free-acid form of orbofiban), YZ211 (free-acid form of sibrafiban), YZ751, and other antagonists, have a much lower efficacy in altering the strength of TF-mediated clot formation (IC(50) >1.0 micromol/L). These data suggest differential efficacy among different GPIIb/IIIa antagonists in inhibiting platelet-fibrin clot retraction despite of equivalent antiaggregatory potency.
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Khurana S, Sanli G, Powers DB, Anderson S, Blaber M. Molecular modeling of substrate binding in wild-type and mutant Corynebacteria 2,5-diketo-D-gluconate reductases. Proteins 2000; 39:68-75. [PMID: 10737928 DOI: 10.1002/(sici)1097-0134(20000401)39:1<68::aid-prot7>3.0.co;2-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
2,5-diketo-D-gluconic acid reductase (2,5-DKGR; E.C. 1.1.1.-) catalyzes the Nicotinamide adenine dinucleotide phosphate (NADPH)-dependent stereo-specific reduction of 2, 5-diketo-D-gluconate (2,5-DKG) to 2-keto-L-gulonate (2-KLG), a precursor in the industrial production of vitamin C (L-ascorbate). Microorganisms that naturally ferment D-glucose to 2,5-DKG can be genetically modified to express the gene for 2,5-DKGR, and thus directly produce vitamin C from D-glucose. Two naturally occurring variants of DKGR (DKGR A and DKGR B) have been reported. DKGR B exhibits higher specific activity toward 2,5-DKG than DKGR A; however, DKGR A exhibits a greater selectivity for this substrate and significantly higher thermal stability. Thus, a modified form of DKGR, combining desirable properties from both enzymes, would be of substantial commercial interest. In the present study we use a molecular dynamics-based approach to understand the conformational changes in DKGR A as the active site is mutated to include two active site residue changes that occur in the B form. The results indicate that the enhanced kinetic properties of the B form are due, in part, to residue substitutions in the binding pocket. These substitutions augment interactions with the substrate or alter the alignment with respect to the putative proton donor group. Proteins 2000;39:68-75.
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Chow CW, Khurana S, Woodside M, Grinstein S, Orlowski J. The epithelial Na(+)/H(+) exchanger, NHE3, is internalized through a clathrin-mediated pathway. J Biol Chem 1999; 274:37551-8. [PMID: 10608808 DOI: 10.1074/jbc.274.53.37551] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Trafficking of the Na(+)/H(+) exchanger isoform 3 (NHE3) between sub-apical vesicles and apical membrane of epithelial cells is a suggested mechanism of regulation of NHE3 activity. When epitope-tagged NHE3 was stably expressed in NHE-deficient Chinese hamster ovary cells, a sizable fraction was found in recycling endosomes. This system was used to analyze the mechanism of endocytosis of NHE3. Immunofluorescence and radiolabeling experiments showed that inhibition of clathrin-mediated endocytosis using hypertonicity, acid treatment, or K(+) depletion inhibited internalization of NHE3. Moreover, transient transfection of an inhibitory mutant of dynamin (DynS45N) blocked the clathrin-mediated uptake of transferrin, as well as the endocytosis of NHE3. In ileal villus cells, endogenous NHE3 was also found to co-purify with isolated clathrin-coated vesicles, thereby confirming their association in native tissues. The role of COP-I subunits in the intracellular traffic of NHE3 was evaluated using ldlF cells, which bear a temperature-sensitive mutation in the epsilon-COP subunit. At the permissive temperature, NHE3 distributed normally, whereas at the restrictive temperature, which induces rapid degradation of epsilon-COP, NHE3 was still internalized, but its subcellular distribution was altered. These results indicate that endocytosis of NHE3 occurs primarily via clathrin-coated pits and vesicles and that normal intracellular trafficking of NHE3 involves an epsilon-COP-dependent step.
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Khurana S, Liby K, Buckley AR, Ben-Jonathan N. Proteolysis of human prolactin: resistance to cathepsin D and formation of a nonangiostatic, C-terminal 16K fragment by thrombin. Endocrinology 1999; 140:4127-32. [PMID: 10465285 DOI: 10.1210/endo.140.9.6955] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The N-terminal 16K fragments of rat and human PRLs possess angiostatic activity. 16K PRL has also been detected in vivo in both humans and rats. Based on an in vitro study, cathepsin D, an acid protease, has been implicated in the generation of rat 16K PRL. However, the proteolytic cleavage of human PRL has not been demonstrated. Our objective was to identify an enzyme that is capable of forming an angiostatic human 16K PRL. To confirm the angiostatic action of rat 16K PRL, the fragment was generated by incubating 23K PRL with rat mammary microsomal fraction at pH 3.2. Upon incubation with human umbilical vein endothelial cells (HUVEC), rat 16K PRL, but not 23K PRL, inhibited basal- and basic fibroblast growth factor-stimulated cell proliferation. Intact rat and human PRLs were then incubated with cathepsin D or acidified microsomal pellets of MCF-7 human breast cancer cells. Analysis by SDS-PAGE showed cleavage of rat, but not human, PRL. Next, hormones were incubated with thrombin at pH 7.4. As shown by SDS-PAGE, digestion of both human and rat PRL by thrombin resulted in the formation of 16K fragments. PRL contained within human amniotic fluid was also cleaved by thrombin. Enzyme specificity was supported by prevention of cleavage by the thrombin inhibitor hirudin. When tested with HUVEC, the human 16K PRL was devoid of angiostatic activity. The activity of this fragment in the Nb2 lymphoma bioassay was 10- to 15-fold lower than that of 23K PRL. Mass spectrometry revealed that the fragment has a mass of 16,878.30+/-15.8 Daltons. Subsequent N-terminal sequencing showed that the thrombin cleavage occurred between amino acid residues 53 (Lys) and 54 (Ala), resulting in the formation of a C-terminal, not an N-terminal, 16K fragment. We conclude that, unlike rat PRL, human PRL is resistant to cleavage by cathepsin D. Thrombin at a physiological pH can generate a C-terminal 16K fragment of human PRL that is not angiostatic and retains little mitogenic activity. We suggest that the precise nature of endogenous 16K PRL fragments that are present in human tissues and body fluids should be carefully examined.
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Gupta S, Arora K, Sampath A, Khurana S, Singh SS, Gupta A, Chaudhary VK. Simplified gene-fragment phage display system for epitope mapping. Biotechniques 1999; 27:328-30, 332-4. [PMID: 10457840 DOI: 10.2144/99272st04] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
We describe a simple and efficient system for epitope mapping by cloning random gene fragments into a specially designed gIIIp-based phage display vector. DNA encoding the antigen of interest is PCR-amplified and partially digested with DNaseI to generate 50-150-bp-long fragments, which are polished with T4 DNA polymerase and dephosphorylated. These fragments are cloned at the 5' end of the gIII after linearizing the vector with SmaI/SrfI, and the ligation is carried out in the presence of restriction enzyme SrfI. The restriction enzyme in the ligation reaction recuts the self-ligated vector but not the recombinants, since ligation with foreign fragments destroys the enzyme recognition site. Dephosphorylation of inserts prevents their chimerization and ensures ligation of single insert per vector molecule. Thus, using the above strategy, which prevents self-ligation of both the insert and the vector, the overall cloning efficiency and, thereby the library size, is improved more than 10-fold compared to the standard blunt-end, ligation-based methods for making similar libraries. The library is further enriched by a single-step infection of E. coli by phages obtained from primary transformants. This step eliminates all the phages that carry insert that are not in-frame with gIIIp and therefore do not display gIIIp. We have shown the utility of the above system in constructing a glutathione-S-transferase (GST) gene-fragment library in phages and identifying the epitope recognized by a monoclonal antibody against GST.
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Redle JD, Khurana S, Marzan R, McCullough PA, Stewart JR, Westveer DC, O'Neill WW, Bassett JS, Tepe NA, Frumin HI. Prophylactic oral amiodarone compared with placebo for prevention of atrial fibrillation after coronary artery bypass surgery. Am Heart J 1999; 138:144-50. [PMID: 10385778 DOI: 10.1016/s0002-8703(99)70260-7] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND Postoperative atrial fibrillation occurs in 20% to 40% of patients undergoing coronary artery bypass grafting (CABG) and contributes to delayed recovery, increased length of stay, and increased hospital cost. Measures at preventing postoperative atrial fibrillation have had mixed results. We report a double-blind trial comparing oral amiodarone with placebo for the prevention of atrial fibrillation after CABG. METHODS AND RESULTS All patients undergoing CABG were considered eligible. Exclusion criteria included bradycardia (<50 beats/min), prior Atrial fibrillation, concurrent therapy with antiarrhythmic drugs, or concomitant valve surgery. Patients were given 2 g of amiodarone (73 patients) or placebo (70 patients) in divided doses 1 to 4 days before surgery and 400 mg daily for 7 days postoperatively. Atrial fibrillation occurred in 24.7% (18 of 43) of patients receiving amiodarone and 32. 8% (23 of 70) of patients receiving placebo (P =.30). Heart rate at onset of atrial fibrillation was 133.4 +/- 26.6 beats/min for amiodarone compared with 152.9 +/- 31.6 beats/min for placebo (P =. 04). Duration of atrial fibrillation was 10.2 +/- 8.1 hours for amiodarone compared with 16.2 +/- 27.5 hours for placebo (P =.67). Patients receiving both beta-blockade and amiodarone had a 16.7% incidence of atrial fibrillation compared with 31.9% in the remaining patients (P =.10). Atrial fibrillation was associated with an increased cost of $7011 compared with those who remained in sinus rhythm ($23,869 +/- $20,894 vs $16,857 +/- $5401 in sinus rhythm). Hospital cost of those taking amiodarone was $18,895 +/- $13,267 compared with $18,839 +/- $11,537.18 for placebo (P =.42). CONCLUSION Postoperative CABG atrial fibrillation is associated with prolonged hospital stay and increased cost. Prophylactic oral amiodarone did not statistically alter the incidence or duration of atrial fibrillation after CABG, although favorable trends were noted. Hospital cost was not affected by therapy with amiodarone.
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Singh G, Kaushal V, Ram S, Kaushal RK, Dhanuka AK, Khurana S. Cysticercus immunoblot assay in patients with single, small enhancing lesions and multilesional neurocysticercosis. THE JOURNAL OF THE ASSOCIATION OF PHYSICIANS OF INDIA 1999; 47:476-9. [PMID: 10778553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
A single, small (< 20 mm), ring or disc shaped contrast enhancing lesion located at the cortical-subcortical junction with minimal or no surrounding edema on computed tomography is the commonest mode of presentation of neurocysticercosis in the Indian subcontinent. Serum samples of 37 patients with these single, small enhancing lesions (SSEL's) and five patients with typical multilesional parenchymal neurocysticercosis were tested by the electro-immunoblot transfer (EITB) assay and the enzyme linked immunosorbent assay (ELISA). EITB was positive in 18 patients (48.64%) and ELISA was positive in 21 patients (56.76%) with SSEL's. On the other hand EITB was positive in all five patients (100%) and ELISA was positive in four patients (80%) with multilesional neurocysticercosis. The low sensitivity of the EITB in the SSEL's is probably linked to an insufficient immune stimulation provided by a single cysticercus cyst.
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Khurana S, Kuns R, Ben-Jonathan N. Heparin-binding property of human prolactin: a novel aspect of prolactin biology. Endocrinology 1999; 140:1026-9. [PMID: 9927340 DOI: 10.1210/endo.140.2.6677] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Prolactin (PRL) shares several characteristics with growth factors and cytokines, many of which are known to bind to heparan sulfate proteoglycans. In this study we examined the heparin-binding properties of selected members of the PRL/GH family, using heparin affinity columns followed by gel electrophoresis/Western blotting. Purified human PRL and its cleaved 16K fragment, but not human GH or placental lactogen, were retained on the heparin column and were displaced by 0.5 M NaCl. Native PRL in human pituitary extracts and amniotic fluid showed a similar binding affinity to heparin as the purified hormone. None of the other hormones tested, e.g., rat, ovine and bovine PRL, glycosylated ovine PRL or rat GH, bound to heparin. Two consensus heparin-binding sequences are present in human PRL but not in the other hormones included in this study. We postulate that the heparin-binding capability of PRL affects its biological activity as a growth factor and the angiostatic actions of its 16K fragment.
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Ram S, Khurana S, Kaushal V, Gupta R, Khurana SB. Incidence of dengue fever in relation to climatic factors in Ludhiana, Punjab. Indian J Med Res 1998; 108:128-33. [PMID: 9805841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023] Open
Abstract
An outbreak of dengue fever occurred in Ludhiana in 1996 and 1997. A total of 505 patients who attended the hospital attached to Dayanand Medical College, Ludhiana were clinically diagnosed to have dengue fever. Of these, 460 cases were noticed between October and December 1996 while during 1997 only 45 dengue fever cases were observed. Serological examination using dengue IgG and IgM blot was performed with single serum samples of 189 patients. Of these, 129 serum samples were detected positive for anti dengue antibodies. Twenty eight patients died in the dengue epidemic, 12 of whom suffered from dengue haemorrhagic fever (DHF) and six with dengue shock syndrome (DSS). Male patients outnumbered the female patients. Seasonal and cyclic pattern of the disease incidence was observed.
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Khurana S, Powers DB, Anderson S, Blaber M. Crystal structure of 2,5-diketo-D-gluconic acid reductase A complexed with NADPH at 2.1-A resolution. Proc Natl Acad Sci U S A 1998; 95:6768-73. [PMID: 9618487 PMCID: PMC22628 DOI: 10.1073/pnas.95.12.6768] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The three-dimensional structure of Corynebacterium 2, 5-diketo-D-gluconic acid reductase A (2,5-DKGR A; EC 1.1.1.-), in complex with cofactor NADPH, has been solved by using x-ray crystallographic data to 2.1-A resolution. This enzyme catalyzes stereospecific reduction of 2,5-diketo-D-gluconate (2,5-DKG) to 2-keto-L-gulonate. Thus the three-dimensional structure has now been solved for a prokaryotic example of the aldo-keto reductase superfamily. The details of the binding of the NADPH cofactor help to explain why 2,5-DKGR exhibits lower binding affinity for cofactor than the related human aldose reductase does. Furthermore, changes in the local loop structure near the cofactor suggest that 2,5-DKGR will not exhibit the biphasic cofactor binding characteristics observed in aldose reductase. Although the crystal structure does not include substrate, the two ordered water molecules present within the substrate-binding pocket are postulated to provide positional landmarks for the substrate 5-keto and 4-hydroxyl groups. The structural basis for several previously described active-site mutants of 2,5-DKGR A is also proposed. Recent research efforts have described a novel approach to the synthesis of L-ascorbate (vitamin C) by using a genetically engineered microorganism that is capable of synthesizing 2,5-DKG from glucose and subsequently is transformed with the gene for 2,5-DKGR. These modifications create a microorganism capable of direct production of 2-keto-L-gulonate from D-glucose, and the gulonate can subsequently be converted into vitamin C. In economic terms, vitamin C is the single most important specialty chemical manufactured in the world. Understanding the structural determinants of specificity, catalysis, and stability for 2,5-DKGR A is of substantial commercial interest.
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Moharana AK, Khurana S, Lal A. An evaluation of cost variation in different brands of antihypertensive agents. THE JOURNAL OF THE ASSOCIATION OF PHYSICIANS OF INDIA 1998; 46:573-4. [PMID: 11273270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
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Ram S, Khurana S, Khurana SB. Incidence of HIV risk and prevention of infection in health care settings. INDIAN JOURNAL OF MEDICAL SCIENCES 1998; 52:239-43. [PMID: 9849034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
Abstract
Tht HIV epidemic has created awareness about blood borne pathogens transmission in health care settings. Although, the risk of transmission of HIV and other blood borne pathogen may account for a very small proportion, yet the potential for such transmission always exists. Despite this, the use of proper and careful sterile procedures is sufficient to substantially reduce or even eliminate the risk of HIV infection.
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Donowitz M, Khurana S, Tse CM, Yun CH. G protein-coupled receptors in gastrointestinal physiology. III. Asymmetry in plasma membrane signal transduction: lessons from brush-border Na+/H+ exchangers. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 274:G971-7. [PMID: 9696719 DOI: 10.1152/ajpgi.1998.274.6.g971] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Signal transduction in epithelial cells adds another level of complexity to the signaling that occurs in symmetrical cells, in the form of the need to coordinate and keep separate signals at the apical and basolateral membranes. Regulation by protein kinases of ileal NaCl absorption and its component brush-border Na+/H+ exchanger are used as an example of how signaling in epithelial cells must deal with spatial localization of signals, protein-protein interactions, signaling molecules, and the involvement of the transport protein being regulated in collecting and focusing the signals generated at the receptor and beyond.
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Wormmeester L, Sanchez de Medina F, Kokke F, Tse CM, Khurana S, Bowser J, Cohen ME, Donowitz M. Quantitative contribution of NHE2 and NHE3 to rabbit ileal brush-border Na+/H+ exchange. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 274:C1261-72. [PMID: 9612213 DOI: 10.1152/ajpcell.1998.274.5.c1261] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Intestinal neutral NaCl absorption, which is made up of brush-border (BB) Na+/H+ exchange linked to BB Cl-/HCO3- exchange, is up- and downregulated as part of digestion and diarrheal diseases. Glucocorticoids stimulate ileal NaCl absorption and BB Na+/H+ exchange. Intestinal BB contains two Na+/H+ exchanger isoforms, NHE2 and NHE3, but their relative roles in rabbit ileal BB Na+/H+ exchange has not been determined. A technique to separate the contribution of NHE2 and NHE3 to ileal BB Na+/H+ exchange activity was standardized by using an amiloride-related compound, HOE-694. Under basal conditions, both NHE2 and NHE3 contribute approximately 50% to ileal Na+/H+ exchange. Glucocorticoids (methylprednisolone) increase BB Na+/H+ exchange (2.5 times) but increase only ileal NHE3 activity (4.1 times), without an effect on NHE2 activity. Thus ileal BB Na+/H+ exchange in animals treated with glucocorticoids is 69% via NHE3. A quantitative Western analysis for NHE3 was developed, using as an internal standard a fusion protein of the COOH-terminal 85 amino acids of NHE3 and maltose binding protein. Glucocorticoid treatment increased the amount of BB NHE3. The quantitative Western analysis showed that NHE3 makes up 0.018% of ileal BB protein in control rabbits and 0.042% (2.3 times as much) in methylprednisolone-treated rabbits. Methylprednisolone treatment did not alter the amount of ileal BB NHE2 protein. NHE3 turnover number was estimated to be 458 cycles/s under basal conditions and 708 cycles/s in glucocorticoid-treated ileum. Thus methylprednisolone stimulates ileal BB Na+/H+ exchange activity only by an effect on NHE3 and not on NHE2; it does so primarily by increasing the amount of BB NHE3, although it also increases the NHE3 turnover number.
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Janecki AJ, Montrose MH, Zimniak P, Zweibaum A, Tse CM, Khurana S, Donowitz M. Subcellular redistribution is involved in acute regulation of the brush border Na+/H+ exchanger isoform 3 in human colon adenocarcinoma cell line Caco-2. Protein kinase C-mediated inhibition of the exchanger. J Biol Chem 1998; 273:8790-8. [PMID: 9535857 DOI: 10.1074/jbc.273.15.8790] [Citation(s) in RCA: 127] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Na+/H+ exchanger isoform 3 (NHE3), an epithelial brush border isoform of the Na+/H+ exchanger gene family, plays an important role in reabsorption of Na+ in the small intestine, the colon, and the kidney. In several cell types, phorbol 12-myristate 13-acetate (PMA) acutely inhibits NHE3 activity by changes in Vmax, but the mechanism of this inhibition is unknown. We investigated the role of subcellular redistribution of NHE3 in the PMA-induced inhibition of endogenous brush border NHE3 in a model human colon adenocarcinoma cell line, Caco-2. Subcellular localization of NHE3 was examined by confocal morphometric analysis complemented with cell surface biotinylation and compared with NHE3 activity evaluated by fluorometric measurement of intracellular pH. PMA inhibited NHE3 activity by 28% (p < 0.01), which was associated with a decrease of the ratio of the brush border/subapical cytoplasmic compartment of NHE3 from approximately 4.3 to approximately 2.4. This translocation resulted in 10-15% of the total cell NHE3 being shifted from the brush border pool to the cytoplasmic pool. These effects were mediated by protein kinase C, since they were blocked by the protein kinase C inhibitor H7. We conclude that inhibition of NHE3 by protein kinase C in Caco-2 cells involves redistribution of the exchanger from brush border into a subapical cytoplasmic compartment, and that this mechanism contributes approximately 50% to the overall protein kinase C-induced inhibition of the exchanger.
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Gupta BK, Kumar R, Sofat R, Khurana S. The role of Gardnerella vaginalis in nonspecific vaginitis in intra uterine contraceptive device users. INDIAN J PATHOL MICR 1998; 41:67-70. [PMID: 9581079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Two Hundred Forty patients who had Intra Uterine Contraceptive Device (IUCD) and manifested of nonspecific vaginitis were investigated for the presence of G. vaginalis. Pure growth of this organism was obtained in 14(5.8%) cases while 116(48.3%) cases showed this organism in association with other organisms e.g. Esch. coli (11.7%), Klebsiella (9.2%), Candida (9.2%), Strept. faecalis (7.3%), Proteus species (5.8%) and Staph. albus (5%).
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Shannon FJ, Boyle TJ, Grant DC, Clyne OJ, Hyland JMP, Mulligan ED, Purcell T, Lawlor P, Reynolds JV, Byrne PJ, Hennessy TPJ, Duff M, Hill ADK, Shering SG, McDermott EW, O’Higgins NJ, Harte M, Corrigan J, Khurana S, Manning F, Kierce B, Corbally M, McNamara DA, Dimitriadis E, Kay E, Redmond HP, Harmey J, Bouchier-Hayes DJ, Chen G, Kelly C, Chen H, Leahy A, Bouchier-Hayes J, Winter DC, Nally K, O’Callaghan J, Harvey BJ, Shanahan F, O’Sullivan GC, Wang H, Wu QD, Redmond HP, Condron C, Bouchier-Hayes D. Waterford surgical October club and surgical section, Royal Academy of Medicine Joint Surgical Symposium. Ir J Med Sci 1998. [DOI: 10.1007/bf02937558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Hnasko R, Khurana S, Shackleford N, Steinmetz R, Low MJ, Ben-Jonathan N. Two distinct pituitary cell lines from mouse intermediate lobe tumors: a cell that produces prolactin-regulating factor and a melanotroph [seecomments]. Endocrinology 1997; 138:5589-96. [PMID: 9389547 DOI: 10.1210/endo.138.12.5656] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The intermediate lobe (IL) of the pituitary produces a PRL-regulating factor (PRF). Targeted tumorigenesis, using the POMC promoter ligated to SV40 large T antigen (Tag), generated transgenic mice that develop IL tumors with PRF activity. Our goal was to establish and characterize a PRF-producing cell line. Two cell lines, which differ markedly in size and morphology, were independently developed from IL tumors and designated mIL5 and mIL39. These cells are transformed, as judged by rapid proliferation, low serum requirements, and generation of secondary tumors in nude mice. RT-PCR revealed that mIL39, but not mIL5 cells, express POMC and dopamine D2 receptors, typical of a melanotroph phenotype. Although mIL5 cells originated from an IL tumor, they do not express messenger RNA for SV40 Tag. The bioassay for PRF used GH3 cells stably transfected with the PRL promoter ligated to a luciferase reporter gene (GH3/luc). Coculture of mIL5 with GH3/luc cells induced cell-density dependent increases in PRL gene expression and release, whereas mIL39 cells showed negligible PRF activity. Incubation of GH3/luc cells with conditioned media from mIL5, but not mIL39 cells, stimulated PRL gene expression and release up to 10-fold. Coculture of mIL5 cells with primary rat anterior pituitary cells stimulated PRL, but not GH, release. Fractionation of mIL5 cell extracts by reverse phase HPLC resolved PRF activity into one major and one minor peak. In conclusion, we have developed two novel and distinct cell lines from mouse intermediate lobe tumors. The first reported melanotroph cell line, mIL39, could provide a valuable model for studying dopaminergic regulation of POMC gene expression and release. In contrast, the mIL5 cells do not express POMC, D2 receptors, or SV40 Tag and appear to have been immortalized by a spontaneous mutation(s). These cells produce and secrete a potent PRF and could be used for the purification and biochemical characterization of PRF.
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Khurana S, Arpin M, Patterson R, Donowitz M. Ileal microvillar protein villin is tyrosine-phosphorylated and associates with PLC-gamma1. Role of cytoskeletal rearrangement in the carbachol-induced inhibition of ileal NaCl absorption. J Biol Chem 1997; 272:30115-21. [PMID: 9374490 DOI: 10.1074/jbc.272.48.30115] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
In ileal absorptive cells, carbachol inhibits NaCl absorption and its component brush border Na+/H+ exchanger, acting via basolateral membrane receptors. This carbachol effect involves (i) activation of brush border phosphatidylinositol 4,5-bisphosphate-specific phospholipase C (PLC) activity and brush border but not basolateral membrane translocation of PLC-gamma1 (Khurana, S., Kreydiyyeh, S., Aronzon, A., Hoogerwerf, W. A., Rhee, S. G., Donowitz, M., and Cohen, M. E. (1996) Biochem. J. 313, 509-518); and (ii) brush border tyrosine kinase(s) because mucosal but not serosal addition of the tyrosine kinase inhibitor genistein prevents the carbachol-induced inhibition of NaCl absorption and brush border Na+/H+ exchange. In the present work we identify a pool of villin (a brush border actin-binding protein) in the microvillus membrane fraction of rabbit ileum; this pool of villin is tyrosine-phosphorylated and associates with brush border membrane PLC-gamma1. Villin is present both in the Triton X-100-soluble and -insoluble fractions of the brush border. The Triton X-100-soluble pool is approximately 4-fold smaller than the brush border pool of villin that is present in the Triton X-100-insoluble fraction. Only the villin present in the Triton X-100-soluble fraction of ileal villus brush border associates with PLC-gamma1 and is tyrosine-phosphorylated. Carbachol increases the tyrosine phosphorylation of villin rapidly (as early as 30 s) and transiently. Carbachol also increases the amount of tyrosine-phosphorylated villin that associates with PLC-gamma1. These studies demonstrate that carbachol effects on NaCl absorption are accompanied by an increase in brush border PLC-gamma1 association with villin and an increase in tyrosine phosphorylation of villin. To study the role of cytoskeletal rearrangement in carbachol-induced inhibition of NaCl absorption, we used the F-actin stabilizing drug jasplakinolide. Jasplakinolide prevents the carbachol inhibition of ileal NaCl absorption. This suggests that F-actin severing is necessary for carbachol to inhibit ileal villus NaCl absorption. Since villin is known to sever actin, these studies suggest a role for villin in the signaling cascade that begins at the basolateral membrane with carbachol binding to its receptor and ends at the apical membrane in inhibition of NaCl absorption.
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Khurana S, Mattson JC, Westley S, O'Neill WW, Timmis GC, Safian RD. Monitoring platelet glycoprotein IIb/IIIa-fibrin interaction with tissue factor-activated thromboelastography. THE JOURNAL OF LABORATORY AND CLINICAL MEDICINE 1997; 130:401-11. [PMID: 9358079 DOI: 10.1016/s0022-2143(97)90040-8] [Citation(s) in RCA: 132] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Computerized thromboelastography (TEG) was used to study platelet glycoprotein IIb/IIIa function, characterize the consequences of the interaction between polymerizing fibrin and activated platelets, and establish a quantitative assay of platelet function. The ability of platelets to augment the shear elastic modulus of blood clots was measured by TEG under conditions of maximal platelet activation during ex vivo clot formation accelerated by recombinant human tissue factor (TF). Under these conditions, platelets significantly enhance clot strength eightfold (relative to platelet-free fibrin clots). This effect, inhibited by cytochalasin D and c7E3 Fab, appears to be dependent on the transmission of platelet contractile force to fibrin, through glycoprotein IIb/IIIa receptors. The c7E3 Fab dose response of TF-TEG clot strength is identical to results with platelet aggregation induced by the thrombin receptor agonist peptide (50% inhibitory concentration (IC50 = 3.6 microg/ml); adenosine diphosphate-induced aggregation is easier to inhibit (IC50 = 1.2 microg/ml). The results obtained with this system are reproducible (coefficient of variation for clot strength 4%; intraclass correlation coefficient 0.96). As a clinical assay, TF-triggered computerized TEG is easy to perform at the bedside, provides on-line results within 30 minutes, and may offer advantages over conventional measures of platelet function.
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Ebell MH, Gaspar DL, Khurana S. Family physicians' preferences for computerized decision-support hardware and software. THE JOURNAL OF FAMILY PRACTICE 1997; 45:137-141. [PMID: 9267372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
BACKGROUND While computers are now widely used by family physicians for billing and patient registration purposes, their use as decision-support tools is still quite limited. The purpose of this study was to determine the current use of computer hardware and software by family physicians, and the characteristics these physicians desire in computerized decision-support hardware and software. METHODS A cross-sectional survey of a random sample of 250 Michigan family physicians was undertaken in mid-1995. These physicians were asked about their current use of a variety of computer hardware and software. They were also asked to rate the value of different kinds of decision-support information potentially available by computer. The survey instrument also gathered the family physicians' preferences for design factors (both hardware and software), such as the size of a computer, the time needed to access information, and the frequency of updates. RESULTS Word processing on desktop computers and hospital information systems are the most widely used computer applications by family physicians. Physicians are most interested in computer-based information on drugs, storage and generation of patient education materials, and accessing treatment recommendations. Most feel that semiannual or annual updates of information are adequate, and would like a uniform interface. A high percentage of physicians (84.5% of all physicians and 94.1% of younger physicians) stated that they would consider carrying a handheld computer. CONCLUSIONS There is significant interest in several types of clinical decision-support software. Based on the results of this study, such software should have following characteristics: (1) be available for handheld as well as networked and desktop computers, (2) include drug information (particularly warnings, interactions, and side effects), (3) include overviews of treatment recommendations, (4) include patient education materials, and (5) have a uniform user interface and be updated at least annually.
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Abstract
The Ellis procedure of serial extraction of gonadotropins and growth hormone (GH) followed by alkaline ethanol extraction was adopted to process freshly frozen buffalo pituitaries. The procedure after slight modification was found very useful as more than 2 mg of GH free immunoreactive prolactin (PRL) could be isolated from each gram of wet pituitary tissue. Further, the biochemical purity and immunobiological potency of the extracted PRL, designated as P-I, was comparable with that of the highly purified samples of homologous and heterologous PRLs. No non-PRL protein was detectable in P-I. Micro-heterogeneity with regard to size, charge, co- and post-translational modifications was also investigated under different conditions of extraction and at different stages of purification. Immunological and biological potencies were compared in homologous competitive enzyme linked immunosorbent assay (ELISA) developed for buffalo PRL and in rat Nb2 lymphoma proliferation assay respectively. Structural heterogeneity was observed in all the preparations checked including fresh pituitary homogenate and highly purified hormone. Nevertheless a 25 K species corresponding to the hormone monomer was always the only paramount form comprising more than 90% of the total PRL protein in all the samples including P-I. Similar size forms were observed in all preparations and were found to be equivalents of monomers, dimers, covalent-and non-covalent multimers, disulphide bridged forms and cleaved fragments. Other sibling species identified were glycosylated PRL, charge isoforms and forms that perhaps differed in their extractability from the pituitary tissue. Strong apparent size heterogeneity was displayed by the monomeric buffalo PRL. In light of these observations and the information on the structural and functional significance and the consequences of polymeric forms, the use of a heterogeneous PRL (P-I) as a reference hormone is recommended for a valid assay.
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Khurana S, O'Neill WW, Sakwa M, Safian RD. Acute occlusion of a left internal mammary artery graft immediately after redo coronary artery bypass surgery: successful rescue PTCA. CATHETERIZATION AND CARDIOVASCULAR DIAGNOSIS 1997; 41:166-9. [PMID: 9184290 DOI: 10.1002/(sici)1097-0304(199706)41:2<166::aid-ccd13>3.0.co;2-o] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A patient with a patent left internal mammary artery (LIMA) to the left anterior descending (LAD) artery required repeat bypass grafting to the distal right coronary artery (RCA). Intraoperative injury to the LIMA resulted in acute anterior myocardial infarction, which was managed by successful rescue percutaneous transluminal coronary angioplasty (PTCA).
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Ram S, Khurana S, Kaushal V, Khurana SB. Infectious diarrhoea--an update. INDIAN JOURNAL OF MEDICAL SCIENCES 1997; 51:196-203. [PMID: 9355725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Infectious diarrhoea is one of the most common illness affecting mankind. Recent advancement have led to detailed understanding of causative agents and the pathogenesis of the infections. Fluid and electrolyte replacement remains the most important aspect of treatment. The role of antimicrobial agents is discussed.
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Khurana S, Raghunathan V, Salunke DM. The variable domain glycosylation in a monoclonal antibody specific to GnRH modulates antigen binding. Biochem Biophys Res Commun 1997; 234:465-9. [PMID: 9177294 DOI: 10.1006/bbrc.1997.5929] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Functionally important glycosylation has been identified in the antigen binding domain of an anti-GnRH monoclonal antibody. Presence of mannose and sialic acid residues is revealed from con A immunoblots and positive staining with a sialic acid detection kit, respectively. Desialylation of the antibody reduces GnRH binding, suggesting the role of terminal sialic acid residues in modulating antigen binding. The crystal structure of the Fab fragment shows electron density adjacent to the antigen binding site which may be attributed to the covalently attached carbohydrate moiety. Thus, the presence of sialic acid containing mannose-rich carbohydrate moiety near the antigen binding site of a monoclonal antibody Fab fragment is relevant for defining antibody specificity.
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128
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Kaur KJ, Khurana S, Salunke DM. Topological analysis of the functional mimicry between a peptide and a carbohydrate moiety. J Biol Chem 1997; 272:5539-43. [PMID: 9038160 DOI: 10.1074/jbc.272.9.5539] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The shared surface topology of two chemically dissimilar but functionally equivalent molecular structures has been analyzed. A carbohydrate moiety (alpha-D-mannopyranoside) and a peptide molecule (DVFYPYPYASGS) bind to concanavalin A at a common binding site. The cross-reactivity of the polyclonal antibodies (pAbs) was used for understanding the topological relationship between these two independent ligands. The anti-alpha-D-mannopyranoside pAbs recognized various peptide ligands of concanavalin A, and the anti-DVFYPYPYASGS pAbs recognized the carbohydrate ligands, providing direct evidence of molecular mimicry. On the basis of differential binding of various rationally designed peptide analogs to the anti-alpha-D-mannopyranoside pAbs, it was possible to identify different peptide residues critical for the mimicry. The comparison of circular dichroism profiles of the designed analogs suggests that the carbohydrate mimicking conformation of the peptide ligand incorporates a polyproline type II structural fold. The concanavalin A binding activity of these analogs was found to have a direct correlation with the topological relationship between peptide and carbohydrate ligands.
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Gupta BK, Sidhu U, Kumar R, Khurana S. Study of fungi associated with bronchopulmonary disorders. INDIAN JOURNAL OF MEDICAL SCIENCES 1996; 50:333-6. [PMID: 9057368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Two hundred samples from sputum (160), bronchial secretions (35) and pleural aspirate (5) were analysed from patients of bronchopulmonary disorders. One hundred nine samples (54.5%) were positive for the fungi. Candida species (50%) were the predominant fungus isolated, followed by Aspergillus species (3.5%). Among various species of Candida, C. albicans accounted for 29.5% cases of bronchopulmonary disorders.
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Ram S, Khurana S, Khurana SB, Vadehra DV, Sharma S, Chhina RS. Microbiological quality & incidence of organisms of public health importance in food & water in Ludhiana. Indian J Med Res 1996; 103:253-8. [PMID: 8707360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Bacteriological analysis of 713 samples of various types of foods and related articles and potable water samples from different places in Ludhiana, Punjab was carried out. The highest counts ranging from 2.5 x 10(6)-7.5 x 10(8) organisms/g were observed in raw vegetables and fruits, followed by 3 x 10(6)-9.8 x 10(7)/ml, 8.3 x 10(4)-8.9 x 10(7)/g and 1 x 10(3)-6.7 x 10(7)/g in fruit juice, milk and its products, and salty/non milk snacks respectively. Fresh chapati, dal, rice, cooked vegetables and karhi etc., showed no microbial contamination. However, samples of these articles from road side cafes gave counts up to 1 x 10(7) organism/g. The most probable number of coliforms and Escherichia coli/100 ml of water ranged from < 1 to > 1100. Although 1332 isolates of 16 types of organisms of public health significance were obtained those of proven enteropathogenicity were enterotoxigenic Esch. coli (55), Esch. coli O157 (3), enteropathogenic Esch. coli (1), enterotoxigenic Klebsiella (23), Streptococcus faecalis (152), Bacillus cereus (133), Staphylococcus aureus (125), Aeromonas spp (47), Salmonella spp (10), Shigella spp (4) and Yersinia enterocolitica (2). Poor quality of potable water and widespread occurrence of enteropathogens in food consumed by the common man in Ludhiana was evident.
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Khurana S, Nath SK, Levine SA, Bowser JM, Tse CM, Cohen ME, Donowitz M. Brush border phosphatidylinositol 3-kinase mediates epidermal growth factor stimulation of intestinal NaCl absorption and Na+/H+ exchange. J Biol Chem 1996; 271:9919-27. [PMID: 8626628 DOI: 10.1074/jbc.271.17.9919] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
In terminally differentiated ileal villus Na+-absorptive cells, epidermal growth factor (EGF) stimulates NaCl absorption and its component brush border Na+/H+ exchanger, acting via basolateral membrane receptors, and as we confirm here, a brush border tyrosine kinase. In the present study we show that brush border phosphatidylinositol 3-kinase (PI 3-kinase) is involved in EGF stimulation of NaCl absorption and brush border Na+/H+ exchange. In rabbit ileum studied with the Ussing chamber-voltage clamp technique, EGF stimulation of active NaCl absorption is inhibited by the selective PI 3-kinase inhibitor wortmannin. PI 3-kinase, a largely cytosolic enzyme, translocates specifically to the brush border of ileal absorptive cells following EGF treatment. This translocation occurs as early as 1 min after EGF treatment and remains increased at the brush border for at least 15 min. EGF also causes a rapid (1 min) and large (4-5-fold) increase in brush border PI 3-kinase activity. Involvement of PI 3-kinase activity in intestinal Na+ absorption is established further by studies done in the human colon cancer cell line, Caco-2, stably transfected with the intestinal brush border isoform of the Na+/H+ exchanger, NHE3 (Caco-2/NHE3 cells). Brush border Na+/H+ exchange activity was measured using the pH-sensitive fluorescent dye 2'7'-bis(carboxyethyl)5-(6)-carboxyfluorescein. EGF added to the basolateral surface but not apical surface of Caco-2/NHE3 cells increased brush border Na+/H+ exchange activity. The EGF-induced increase in brush border Na+/H+ exchange activity was completely abolished in cells pretreated with wortmannin. EGF treatment caused increased tyrosine phosphorylation of PI 3-kinase in both ileal brush border membranes and Caco-2/NHE3 cells, suggesting that a tyrosine kinase upstream of the PI 3-kinase is involved in the EGF effects on Na+ absorption. In conclusion, the present study provides evidence in two separate intestinal models, the ileum and a human colon cancer cell line, that PI 3-kinase is an intermediate in EGF stimulation of intestinal Na+ absorption.
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Khurana S, Kreydiyyeh S, Aronzon A, Hoogerwerf WA, Rhee SG, Donowitz M, Cohen ME. Asymmetric signal transduction in polarized ileal Na(+)-absorbing cells: carbachol activates brush-border but not basolateral-membrane PIP2-PLC and translocates PLC-gamma 1 only to the brush border. Biochem J 1996; 313 ( Pt 2):509-18. [PMID: 8573085 PMCID: PMC1216936 DOI: 10.1042/bj3130509] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In ileal Na+ absorptive cells, carbachol inhibits NaCl absorption and its component brush-border Na+/H+ exchanger, acting via basolateral membrane (BLM) receptors. This carbachol effect involves brush-border but not BLM protein kinase C. In the present work we describe another asymmetric aspect of signal transduction in these epithelial cells, this time involving phosphatidylinositol 4,5-bisphosphate (PIP2)-specific phospholipase C (PLC). Thirty seconds and 1 min after carbachol treatment, brush-border PIP2-specific PLC activity increased, returning to control levels by 2.5 min. Involvement of brush-border tyrosine kinase(s) in this effect was suggested by inhibition of the carbachol effect on NaCl absorption by the tyrosine kinase inhibitor genistein, added to the mucosal but not the serosal surface. Luminal genistein pretreatment also prevented the carbachol-induced increase in brush-border PLC activity. In contrast, carbachol exposure did not change the BLM PIP2-specific PLC activity. Western analysis and immunoprecipitation demonstrated that PLC-gamma 1 is present in the brush border and that carbachol increases the PLC-gamma 1 amount in the brush border. Both the brush border and BLM contain PLC-beta 3 and a small amount of PLC-delta 1 but no PLC-beta 1, whereas BLM lacks detectable PLC-gamma 1. No change in PLC-beta 3 or PLC-delta 1 amount in the brush border occurred with carbachol exposure. No change in tyrosine phosphorylation of brush-border PLC-gamma 1 occurred with carbachol treatment. The Ca2+ ionophore A23187 did not alter PIP2-specific PLC activity in either the brush border or the BLM. These studies demonstrate that carbachol but not Ca2+ ionophore effects on brush-border NaCl absorption are associated with increases in brush-border but not BLM PIP2-specific PLC activity and in the amount of brush-border PLC-gamma 1, and involve tyrosine phosphorylation. This asymmetric aspect of epithelial signal transduction, together with the previous demonstration of localization of high-sensitivity IP3 stores to the apical membrane area in intestinal epithelial cells, shows that different aspects of signal transduction occur at the apical and basolateral membranes in epithelial and requires studies in both domains to define mechanisms of intracellular signalling.
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Khurana S, K M. Efficacy of passive transfer of proteins from preparative polyacrylamide gels to nitrocellulose membranes. INDIAN JOURNAL OF BIOCHEMISTRY & BIOPHYSICS 1995; 32:245-8. [PMID: 8713744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Passive transfer of proteins from preparative polyacrylamide gels to nitrocellulose membrane (NTC) was investigated. The transfer was carried out without the removal of sodium dodecyl sulphate from the denaturing gels. The transfer was quick, easy to perform, and does not require any apparatus. More than one replica of the same band can be obtained by successive transfer to more than one NTC without significantly affecting the Coomassie Brilliant Blue (CBB) staining ability of protein bands left in the gel. A fraction of protein transferred passively in the absence of electrical current from as low as 1.5 micrograms of protein per band in a 2 mm thick gel was found sufficient for detection with amido black staining, and more so by immunostaining. The method was found highly satisfactory for seven proteins (14 kDa to 66 kDa) checked in the present study and can be adopted, after checking its efficacy for any protein, for routine qualitative tests.
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Ram S, Khurana S, Khurana SB. Rapid identification of colonization factor antigens I & II of enterotoxigenic Escherichia coli by coagglutination test. Indian J Med Res 1995; 102:156-8. [PMID: 8543358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Specific antisera for colonization factor antigens (CFA/I and CFA/II) were adsorbed to Staphylococcus aureus Cowan I strain, ATCC 12598 to make coagglutination (CoA) reagents for detection of CFAs in enterotoxigenic Esch. coli (ETEC) isolates. Among 1782 strains of Esch. coli isolated from patients with acute diarrhoea, 238 (13.4%) strains exhibited CFA expression. Most prevalent CFA/I positive serogroups were 015, 0148, 0153, 020, 0128, 0114 and 078. CFA/II was detected among isolates of serogroup 080, 085, 06 and 08. Ten ETEC isolates each of serogroups 04, 07, 061, 068, 0117 and 0158 did not show presence of CFA/I or CFA/II. CoA technique proved an appropriate, rapid diagnostic tool which can be used for screening large number of Esch. coli isolates in epidemiological studies.
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Kumar R, Khurana S, Gupta B. Cryptococcal meningitis--a case report. INDIAN JOURNAL OF MEDICAL SCIENCES 1995; 49:184-5. [PMID: 8906963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Two cases of Cryptococcal meningitis were encountered in the recent past. History of predisposing factors was available in both the patients. The diagnosis of these patients was made on the basis of smear, culture and animal pathogenicity tests.
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Takkar VP, Kumar R, Takkar R, Khurana S. Resurgence of chloramphenicol sensitive Salmonella typhi. Indian Pediatr 1995; 32:586-7. [PMID: 8613320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Khurana S. Shilpa Khurana. Interview by Carla McGlone. IMPRINT 1995; 42:27-8. [PMID: 7657353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Abstract
Viral infections constitute more than 60% of acute lower respiratory illnesses. Respiratory syncytial virus (RSV) and parainfluenza viruses are the most frequent etiologic agents. After transmission by large droplet aerosol or direct contact, the viruses gain entry into host cells through specific viral surface proteins; subsequently, pathogenetic mechanisms cause tissue injury and result in clinical disease. In the intensive care unit the mainstay of treatment is primarily supportive. Nonspecific treatment may include nebulized beta-agonists, aminophylline, and steroids. Ribavarin is the only specific antiviral agent approved for respiratory syncytial virus infection but its efficacy remains controversial. New therapies and vaccines offer hope for improved outcome from viral respiratory infections such as RSV.
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Tse CM, Levine SA, Yun CH, Khurana S, Donowitz M. Na+/H+ exchanger-2 is an O-linked but not an N-linked sialoglycoprotein. Biochemistry 1994; 33:12954-61. [PMID: 7524659 DOI: 10.1021/bi00248a003] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A polyclonal antibody (Ab597) was produced in rabbit against a fusion protein of glutathione-S-transferase and the last 87 amino acids of the Na+/H+ exchanger isoform, NHE2. By Western blotting, Ab597 recognized proteins of 75 and 85 kDa in PS120/NHE2 membranes (PS120 cells stably transfected with NHE2), and this antibody did not cross-react with NHE1 and NHE3. When Ab597 was used to immunocytochemically stain PS120/NHE2 cells, permeabilization of the cells was required for staining, confirming the putative membrane topology of NHE2 that the C-terminus is cytoplasmic. NHE1 is N-glycosylated. NHE2 was predicted to be N-glycosylated as it contains one potential N-linked glycosylation site (N350VS), which is conserved among NHE1, NHE3, and NHE4. However, NHE2 was resistant to peptide:N-glycosidase F (PNGase F) and endoglycosidase H (Endo H) digestion, suggesting that NHE2 is not N-glycosylated. In contrast, neuraminidase shifted the mobility of the 85 kDa NHE2 protein in PS120/NHE2 membranes into an 81 kDa band, and O-glycanase further shifted the mobility of the neuraminidase-treated 81 kDa protein to 75 kDa. Incubation of PS120/NHE2 cells with benzyl N-acetyl-alpha-D-galactosaminide (Bz alpha GalNAc), an O-glycosylation inhibitor, decreased the size of the 85 kDa protein to 81 kDa. This treatment had no effect on the initial rate of Na+/H+ exchange of PS120/NHE2 cells. The 75 kDa protein was not affected by the glycosidase treatment of PS120/NHE2 membranes or the Bz alpha GalNAc treatment of PS120/NHE2 cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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Wander GS, Khurana SB, Gulati R, Sachar RK, Gupta RK, Khurana S, Anand IS. Epidemiology of coronary heart disease in a rural Punjab population--prevalence and correlation with various risk factors. Indian Heart J 1994; 46:319-23. [PMID: 7797219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
An epidemiological study to find out the prevalence of coronary heart disease (CHD) and the influence of risk factors on the prevalence of CHD in a total rural community of Punjab was conducted in Pohir, situated near Ludhiana. A total of 1100 individuals (623 males and 477 females) out of a possible 1617 individuals (> 30 yrs) living in 3 villages were studied. In each case a detailed history, physical examination and a 12 lead electrocardiogram (ECG) were recorded. Samples for blood sugar and serum cholesterol were taken. By Epstein's criteria of ECG (using the Minnesota coding), the prevalence of CHD was 30.8/1000, being higher in women (37.7/1000) than in men (25.6/1000). By a clinical judgement method considering history, ECG and treadmill testing (TMT) collectively, prevalence was 31.8/1000, being still higher in women (33.5/1000) than in men (30.5/1000). The prevalence of various risk factors like hypertension, smoking, hypercholesterolemia and diabetes was found to be 14.5%, 8.9%, 7.0% and 4.6% respectively. Of the various risk factors tested, hypertension, hypercholesterolemia and a positive family history showed an association with CHD. Only 38% of patients with CHD, 37% of the hypertensives and 52% of the diabetics were aware of its presence. The knowledge in the general population about risk factors causing CHD is poor.
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Raghunathan V, Khurana S, Gupta V, Khurana R, Udgaonkar JB, Salunke DM. Crystallization and molecular packing analysis of barstar crystals. J Mol Biol 1994; 243:533-6. [PMID: 7966279 DOI: 10.1006/jmbi.1994.1679] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Barstar, the natural inhibitor of barnase crystallizes in many different crystal forms under almost identical conditions. Although barstar is a monomeric protein, it crystallizes with four molecules in the asymmetric unit in two crystal forms, rhombohedral (space group R3; a = b = 118.0 angstrum; c = 75.5 angstrum) and tetragonal (space group P4; a = b = 105.1 angstrum; c = 36.0 angstrum), which exist simultaneously under identical crystallization conditions. The relation between the four molecules in the asymmetric unit of the crystals belonging to space group P4 can be interpreted in terms of a small distortion in the crystallographic symmetry of the higher symmetry space group P422.
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142
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Goyal SC, Singh P, Khurana S, Ram S. Bacteraemia in urological surgical procedures. INDIAN J PATHOL MICR 1994; 37:415-20. [PMID: 7868175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
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143
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Spears JR, Zhan H, Khurana S, Karvonen RL, Reiser KM. Modulation by beta-aminopropionitrile of vessel luminal narrowing and structural abnormalities in arterial wall collagen in a rabbit model of conventional balloon angioplasty versus laser balloon angioplasty. J Clin Invest 1994; 93:1543-53. [PMID: 8163657 PMCID: PMC294173 DOI: 10.1172/jci117133] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
This study was designed to assess the potential relationship between the late loss of angiographic luminal diameter and biochemical abnormalities of arterial wall collagen in rabbits subjected to angioplasty, and to test the hypothesis that beta-aminopropionitrile (beta APN), an inhibitor of lysyl oxidase, would inhibit such changes when administered orally for 1 mo after angioplasty. Endovascular injury was induced in rabbit iliac arteries by ipsilateral balloon angioplasty (BA) and by contralateral balloon angioplasty accompanied by exposure to continuous wave neodymium: yttrium aluminum garnet laser radiation (LBA). Computer measurement of angiographic luminal diameter demonstrated significant vessel narrowing at 1 and 6 mo after both procedures. By quantitative histology, the majority of the 1-mo loss in angiographic diameter could not be attributed to neointimal thickening. Analysis of collagen cross-linking by HPLC in collagen obtained from the LBA-injured segments of the arteries 1 mo after angioplasty revealed a significant increase, relative to values from uninjured arteries (P < 0.05), in the difunctional cross-link dihydroxylysinonorleucine (DHLNL). 6 mo after angioplasty, the content of hydroxypyridinium, the trifunctional maturational product of DHLNL, was significantly elevated in both BA- and LBA-treated arteries compared with values from uninjured arteries (P < 0.05). In animals administered beta APN, luminal narrowing at 1 mo, compared with controls, was attenuated (P < 0.01) and DHLNL content was decreased (P < 0.05) in arteries subjected to LBA, but not in arteries subjected to BA. The results suggest that lathyrogenic agents may be efficacious in favorably modulating LBA-induced alterations in vessel diameter and mural connective tissue.
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144
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Talib VH, Khurana S, Verma SK. Towards a successful quality control programme in laboratory medicine. INDIAN J PATHOL MICR 1994; 37:127-8. [PMID: 7959978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
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145
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Khurana S, Kunchaparty S, Muralidhar K. A possible urease-based homologous ELISA for buffalo prolactin. INDIAN JOURNAL OF EXPERIMENTAL BIOLOGY 1994; 32:81-5. [PMID: 8045617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The feasibility of a direct binding as well as competitive ELISA using urease labelled probe is described for buffalo pituitary prolactin. Rabbit anti-buPRL serum and goat anti-rabbit IgG conjugated to urease were used as primary and secondary antibodies respectively. Assay was performed in polystyrene wells pretreated with 3-amino-propyltriethoxysilane (APTES) compound. APTES pretreatment provided a more receptive surface for prolactin (PRL). In direct binding mode the assay could detect 24 pg of PRL per well. In competition mode the detection limit was less than 0.1 ng of competitor PRL per well. Urease-based ELISA was found highly sensitive when the substrate solution containing pH indicator, bromocresol purple, was used at lower pH (4-4.2). No false positive reactions occurred in the control wells. A good parallelism between buffalo serum sample inhibition curve and the standard PRL inhibition curve was observed.
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146
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Muralidhar K, Kumar TR, Chadha N, Khurana S, Khanna T, Sharma HP. Strategies for purification of four reproductive hormones from the same batch of buffalo (Bubalus bubalis) pituitaries. INDIAN JOURNAL OF EXPERIMENTAL BIOLOGY 1994; 32:73-80. [PMID: 8045616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The occurrence of different reproductive hormones like LH, FSH, TSH and prolactin, in different side fractions obtained during the extraction of buffalo pituitary glands either by the procedure of Papkoff et al. [Arch Biochem Biophys, 111 (1965) 431] or by that of Ellis [Endocrinology, 69 (1961) 554], was examined with the aid of antisera to respective heterologous hormones as well as bio-assays. Thus in the procedure of Papkoff et al., the SP-Sephadex fractions could be taken for purification of LH and TSH, while the acid pellet yielded prolactin. Further it was shown that 50% (NH4)2SO4 could be directly size fractionated and following cation exchange chromatography yields LH and TSH. FSH could be purified from 80% ammonium sulphate pellet. In another protocol of Ellis, differential extraction and chromatographic separation yielded all the four reproductive hormones. Some of the physico-chemical and immunobiological characteristics of these hormones are described.
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147
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Takkar VP, Kumar R, Khurana S, Takkar R. Comparison of ciprofloxacin versus cephelexin and gentamicin in the treatment of multi-drug resistant typhoid fever. Indian Pediatr 1994; 31:200-1. [PMID: 7875846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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148
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Khanchi RS, Bansal SL, Aggarwal S, Khurana S, Mohindra RK. Computation of activities induced by 14 MeV neutrons for the elemental analysis of human tissues, skin and tooth enamel. Appl Radiat Isot 1994; 45:129-32. [PMID: 8287054 DOI: 10.1016/0969-8043(94)90159-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
For planning experiments for neutron activation analysis investigations at 14 MeV, suitable induced beta activities in Bq/g/neutron flux have been computed via appropriate reactions for the estimation of 19F, 23Na, 24Mg, 31P, 32S, 35,37Cl, 39K, 40Ca, 55Mn, 56Fe, 66Zn, 63,65Cu, 107,109Ag and 208Pb. The computational work for (n,p); (n, alpha); (n,n') and (n,2n) reactions induced with 14 MeV neutrons are based on the pre-equilibrium emission mechanism and also the compound nucleus theory with otpical model potential and pairing energy corrections. The cross-sections obtained by pre-equilibrium computer codes are reasonable and have been used in the present computations.
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149
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Greval RS, Khurana S, Shobha R, Sharma SK. Anaerobic infection in chronic maxillary sinusitis. INDIAN JOURNAL OF MEDICAL SCIENCES 1993; 47:201-3. [PMID: 8270303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
1) Ten per cent of cases of chronic maxillary sinusitis in a series of 50 cases treated in the ENT department of Dayanand Medical College, Ludhiana, were caused by anaerobic infection. 2) The causative anaerobic micro-organisms encountered were Peptostreptococcus and Clostridium species. 3) Treatment should, therefore, include metronidazole, especially in those cases refractory to conventional antibiotic therapy.
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150
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Gupta BK, Kumar S, Kumar RA, Khurana S. Mycological aspects of dermatomycosis in Ludhiana. INDIAN J PATHOL MICR 1993; 36:233-7. [PMID: 8300168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
159 clinically diagnosed cases of dermatomycosis were examined and subjected to mycological study. In the direct microscopic examination, 78 (49.05%) cases were positive and cultures were positive in 66 (41.5%) cases. The common clinical presentation was T. corporis in 60 (37.7%) cases. The commonest species encountered was T. rubrum (42.42%) followed by Epidermophyton floccusum (15.15%), Candida (13.63%), T. violaceum (12.12%), T. mentagrophyte (6.06%) & T. tonsurans (1.5%) in this study. The prevalence of infection was more in males.
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