Polymicrobial keratitis.
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Eye Infections, Bacterial↗
Biomedical subjects
S Dhawan
Publications and source records attributed to S Dhawan.
Use of RAPD and AFLP markers to identify inter- and intraspecific hybrids of Mentha.
Three controlled crosses were carried out involving Mentha arvensis and Mentha spicata [M. spicata CIMAP/C30 x M. spicata CIMAP/C33 (cv. Neera); M. arvensis CIMAP/C18 x CIMAP/C17 (cv. Kalka); and M. arvensis CIMAP/C17 x M. spicata CIMAP/C33]. The parents were subjected to random amplified polymorphic DNA (RAPD) analysis with 80 primers, and polymorphic primers were tested for detecting coinherited RAPD profiles among the progeny of these crosses. Of 50 seedlings tested from each intraspecific cross, all demonstrated dominant profiles with the selected RAPD primers except the detected hybrid from respective crosses. Coinherited markers could be detected with the primers OPJ 01, MAP 06, OPT 08, and OPO 20 for M. arvensis; OPJ 05, OPJ 14, OPO 19, and OPT 09 for M. spicata; and OPJ 07, OPJ 10, OPJ 11, OPJ 14, and OPO 02 for the cross M. arvensis x M. spicata. In our amplified fragment length polymorphism (AFLP) analysis, 40 coinherited marker fragments were identified for the cross involving M. arvensis, 32 for the cross involving M. spicata, and 41 for the interspecific cross between M. arvensis and M. spicata. In all crosses, similarity values between the parents were less than those between the parents and the hybrids. Although RAPD markers are generally considered dominant, it is possible to identify a few codominant markers that behave like restriction fragment length polymorphism (RFLP) markers. This molecular marker system may be helpful in rapidly screening out hybrids in crops where cross-pollination is a problem.
Breeding↗
Blood schizontocidal activity of azithromycin and its combination with alpha/beta arteether against multi-drug resistant Plasmodium yoelii nigeriensis, a novel MDR parasite model for antimalarial screening.
Many different drug-resistant lines of rodent malaria are available as screening models. It is obligatory to screen new compounds for antimalarial activity against a series of resistant lines in order to identify a compound with potential for the treatment of multi-drug resistant (MDR) malaria infections. Instead of using a battery of resistant lines, a single MDR Plasmodium yoelii nigeriensis strain that shows a wide spectrum of drug resistance to high doses of chloroquine, mepacrine, amodiaquine, mefloquine, quinine, quinidine, halofantrine as well as tetracyclines, fluoroquinolines and erythromycin, was used to assess the blood schizontocidal efficacy of a new macrolide azithromycin and other antibiotics. The present study shows that only azithromycin has the potential to control an MDR P. y. nigeriensis infection in Swiss mice, provided the treatment with a dose of 50-100 mg/kg/day by oral route is continued for a period of 7 days. Tetracycline, oxytetracycline, doxycyline, erythromycin, ciprofloxacin and norfloxacin, although active in vitro, failed to protect the mice. Tetracycline, ciprofloxacin and norfloxacin combinations with chloroquine did not control the infection. Additionally, the antimalarial efficacy of azithromycin can be potentiated with the addition of arteether, which is an ethyl ether derivative of artemisinin. A total (100%) curative effect has been obtained with a shorter regimen of 4 days only.
Animals↗
Chitosan microspheres as a potential carrier for drugs.
Chitosan is a biodegradable natural polymer with great potential for pharmaceutical applications due to its biocompatibility, high charge density, non-toxicity and mucoadhesion. It has been shown that it not only improves the dissolution of poorly soluble drugs but also exerts a significant effect on fat metabolism in the body. Gel formation can be obtained by interactions of chitosans with low molecular counterions such as polyphosphates, sulphates and crosslinking with glutaraldehyde. This gelling property of chitosan allows a wide range of applications such as coating of pharmaceuticals and food products, gel entrapment of biochemicals, plant embryo, whole cells, microorganism and algae. This review is an insight into the exploitation of the various properties of chitosan to microencapsulate drugs. Various techniques used for preparing chitosan microspheres and evaluation of these microspheres have also been reviewed. This review also includes the factors that affect the entrapment efficiency and release kinetics of drugs from chitosan microspheres.
Animals↗
Release of diltiazem hydrochloride from hydrophilic matrices of polyethylene oxide and carbopol.
The mucoadhesion, swelling, and drug release behavior of polyethylene oxide (PEO) and carbopol (CP) matrices were studied using a water soluble model drug diltiazem hydrochloride. The mucoadhesive strength of the matrices increased with increase in polymer content. The results showed that PEO was more mucoadhesive than CP. Mucoadhesion of the tablets was dependent upon the swelling. Swelling was ascertained by measuring the axial and radial expansion of matrix tablets following exposure to media of physiological ionic strength. There was a marked increase in the swelling index of matrices containing high polymer content of PEO as compared to CP. Drug release kinetics were found to be closely related to dissolution and swelling properties of the matrices. The release was found to be non-Fickian with n (release exponent) values ranging from 0.45-0.58. At a constant polymer content (15.84% w/w), the main contributing factor for the mucoadhesion, swelling, and release was the amount of PEO.
Acrylic Resins↗
High statistics measurement of the K+-->pi0e+nu (K+e3) branching ratio.
E865 at the Brookhaven National Laboratory AGS collected about 70 000 K(+)(e3) events to measure the K(+)(e3) branching ratio relative to the observed K+-->pi(+)pi(0), K+-->pi(0)micro(+)nu, and K+-->pi(+)pi(0)pi(0) decays. The pi(0) in all the decays was detected using the e(+)e(-) pair from pi(0)-->e(+)e(-)gamma decay and no photons were required. Using the 2002 Particle Data Group branching ratios for the normalization decays, we obtain BR(K(+)(e3(gamma)))=(5.13+/-0.02(stat)+/-0.09(syst)+/-0.04(norm))%, where K(+)(e3(gamma)) includes the effect of virtual and real photons. This result is approximately 2.3sigma higher than the current Particle Data Group value. Implications for the V(us) element of the CKM matrix, and the matrix's unitarity are discussed.
Journal Article↗
Zinc-naproxen complex: synthesis, physicochemical and biological evaluation.
Naproxen has a propensity to cause ulcers whereas zinc ions are known to possess an anti-ulcer and anti-inflammatory activity. Therefore, zinc complex of naproxen was prepared by adding zinc sulfate to an aqueous solution of sodium naproxen and its structure was characterized by IR, 1H NMR and 13C NMR, UV, DSC, atomic absorption spectroscopy, and elemental analysis. Anti-inflammatory studies, using the carrageenan-induced hind paw oedema showed that there was a significant difference (P<0.05, ANOVA plotted by Dunnet's test) in the anti-inflammatory activity of naproxen, its zinc complex, and the physical mixture of naproxen and zinc sulfate. In addition, zinc complex of naproxen showed a significant reduction in ulcers (lesion index (LI)) as compared to that of naproxen and physical mixture of naproxen and zinc sulfate. Thus, the use of the complex may be preferable to naproxen alone.
Animals↗
Spatio-temporal expression of wnt-1 during embryonic-, wing- and silkgland development in Bombyx mori.
A homologue of the segment polarity gene wnt-1 from Bombyx mori (Bmwnt-1) has been characterized. The segmentally reiterated pattern of Bmwnt-1 transcrip9t distribution in B. mori embryos suggested its segment polarity function. Maximal levels of Bmwnt-1 RNA during embryonic development were reached by stage 21A. In the larval stages, Bmwnt-1 was expressed in the fore- and hindwing discs, ovaries, testes and gut, reminiscent of the expression domains in Drosophila. Bmwnt-1 was expressed in the wing-margin area of both the fore- and hindwing discs. The pattern of wnt-1 expression in the hindwing discs was similar to that in the butterfly Precis coenia but subtle differences existed in forewing discs of the two species, which correlated well with the absence of proximal bands of pigmentation in the adult Bombyx wings. In addition, Bmwnt-1 was expressed in the silkglands and the expression was confined to the anterior sub-compartment within the middle silkglands throughout development from the embryonic to late larval stages. This domain of Bmwnt-1 expression overlapped with those of Cubitus interruptus (BmCi) and sericin-2 but excluded the Engrailed expression domain viz. the middle and posterior sub-compartments of middle silkglands. Bmwnt-1 expression was detected only during the intermoults and not in the moulting periods.
Animals↗
Ethidium bromide stimulated hyper laccase production from bird's nest fungus Cyathus bulleri.
AIMS: Effect of ethidium bromide, a DNA intercalating agent, on laccase production from Cyathus bulleri was studied. METHODS AND RESULTS: The bird's nest fungus, Cyathus bulleri was grown on 2% (w/v) malt extract agar (MEA) supplemented with 1.5 microg ml(-1) of the phenanthridine dye ethidium bromide (EtBr) for 7 d and when grown subsequently in malt extract broth (MEB), produced a 4.2-fold increase in laccase production as compared to the untreated fungus. The fungal cultures following a single EtBr treatment, when regrown on MEA devoid of EtBr, produced a sixfold increase in laccase in MEB. However, on subsequent culturing on MEA in the absence of EtBr, only a 2.5-fold increase in laccase production could be maintained. In another attempt, the initial EtBr-treated cultures, when subjected to a second EtBr treatment (1.5 microg ml(-1)) on MEA for 7 d, produced a 1.4-fold increase in laccase production in MEB. CONCLUSIONS: The white-rot fungus Cyathus bulleri, when treated with EtBr at a concentration of 1.5 microg ml(-1) and regrown on MEA devoid of EtBr, produced a sixfold increase in laccase production in MEB. SIGNIFICANCE AND THE IMPACT OF THE STUDY: The variable form of C. bulleri capable of hyper laccase production can improve the economic feasibility of environmentally benign processes involving use of fungal laccases in cosmetics (including hair dyes), food and beverages, clinical diagnostics, pulp and paper industry, industrial effluent treatment, animal biotechnology and biotransformations.
Animals↗
Performance liquid chromatographic analysis of glipizide: application to in vitro and in vivo studies.
This paper describes the validation of a sensitive, accurate, and reproducible method for the determination of a release profile of glipizide from controlled-release dosage forms. In this method, an in vitro dissolution profile of commercial controlled-release dosage forms is determined using a reversed-phase C(18) column, mobile phase (acetonitrile-buffer, 0.05 M KH(2)PO(4) adjusted to pH 3.5 with orthophosphoric acid), and UV detection at a wavelength of 275 nm. The method is validated for linearity, accuracy, precision, and detection and quantitation limits. The same method can be exploited to determine the plasma concentration of glipizide. The peak area versus plasma concentration is linear over the range of 12.5-1000 ng/mL and the detection limit was 5 ng/mL in plasma. The average accuracy was 99.90% with a relative standard deviation (RSD) of not more than 3%. Repeatability and reproducibility were found to be good with an RSD of less than 3%.
Chromatography, Liquid↗
Nifedipine loaded chitosan microspheres prepared by emulsification phase-separation.
A high yield of nifedipine-chitosan microspheres could be obtained using an emulsification phase-separation method. A high level of entrapment of nifedipine in the microspheres was achieved. The microspheres exhibited excellent swelling properties. Differential scanning calorimetry, X-ray diffractometry, and scanning electron microscopy confirmed that at 1.84% loading, nifedipine was dispersed molecularly. The microspheres exhibited faster release at low loadings compared to high loadings. Fitting the data to the coupled Fickian/case II equation, showed that at low loadings polymer relaxation coefficients (k2) were high. As the polymer content increased in the microspheres, the value of n (diffusional exponent characteristic of the release mechanism) approached one, which is indicative of zero order.
Chitin↗
Experimental study of the radiative decays K+-->mu(+)nue(+)e(-) and K+-->e(+)nue(+)e(-).
Experiment 865 at the Brookhaven Alternating Gradient Synchrotron obtained 410 K+-->e(+)nue(+)e(-) and 2679 K+-->mu(+)nue(+)e(-) events including 10% and 19% background. The branching ratios were measured to be [2.48+/-0.14(stat)+/-0.14(syst)]x10(-8) (m(ee)>150 MeV) and (7.06+/-0.16+/-0.26)x10(-8) (m(ee)>145 MeV), respectively. Results for the decay form factors are presented.
Journal Article↗
New measurement of K(+)(e4) decay and the s-pave pi pi-scattering length a(0)(0).
A sample of 4 x 10(5) events from the decay K(+)-->pi(+)pi(-)e(+)nu(e) (K(e4)) has been collected in experiment E865 at the Brookhaven Alternating Gradient Synchrotron. The analysis of these data yields new measurements of the K(e4) branching ratio [(4.11+/-0.01+/-0.11) x 10(-5)], the s-wave pi pi scattering length [a(0)(0) = 0.216+/-0.013(stat)+/-0.004(syst)+/-0.005(theor)], and the form factors F, G, and H of the hadronic current and their dependence on the invariant pi pi mass.
Journal Article↗
Teratomas in infancy and childhood.
A 10-year-experience with 42 cases of teratomas in paediatric age group is presented. The commonest type of teratoma was sacrococcygeal followed by ovarian and retroperitoneal teratomas. An analysis of clinical profile, malignant potential, management, prognostic factors and follow up is discussed with review of literature.
Age of Onset↗
Detection of caspase activation in situ by fluorochrome-labeled caspase inhibitors.
Apoptosis is dependent on the activation of a group of proteolytic enzymes called caspases. Caspase activation can be detected by immunoblotting using caspase-specific antibodies or by caspase activity measurement employing pro-fluorescent substrates that become fluorescent upon cleavage by the caspase. Most of these methods require the preparation of cell extracts and, therefore, are not suitable for the detection of active caspases within the living cell. Using FAM-VAD-FMK, we have developed a simple and sensitive assay for the detection of caspase activity in living cells. FAM-VAD-FMK is a carboxyfluorescein (FAM) derivative of benzyloxycarbonyl-valine-alanine-aspartic acid-fluoromethyl ketone (zVAD-FMK), which is a potent broad-spectrum inhibitor of caspases. FAM-VAD-FMK enters the cell and irreversibly binds to activated caspases. Cells containing bound FAM-VAD-FMK can be analyzed by flow cytometry, fluorescence microscopy, or a fluorescence plate reader. Using FAM-VAD-FMK, we have measured caspase activation in live non-adherent and adherent cells. We show that FAM-VAD-FMK labeled Jurkat and HeLa cells that had undergone apoptosis following treatment with camptothecin or staurosporine. Non-stimulated negative control cells were not stained. Pretreatment with the general caspase inhibitor zVAD-FMK blocked caspase-specific staining in induced Jurkat and HeLa cells. Pretreatment of staurosporine-induced Jurkat cells with FAM-VAD-FMK inhibited affinity labeling of caspase-3, -6, and -7, blocked caspase-specific cell staining, and led to the inhibition of apoptosis. In contrast, the fluorescent control inhibitor FAM-FA-FMK had no effect. Measurement of caspase activation in 96-well plates showed a 3- to 5-fold increase in FAM-fluorescence in staurosporine-treated cells compared to control cells. In summary, we show that FAM-VAD-FMK is a versatile and specific tool for detecting activated caspases in living cells.
Affinity Labels↗
Nifedipine loaded chitosan microspheres: characterization of internal structure.
In the present investigation, a simple technique was employed to obtain cross-sections of unloaded and nifedipine loaded chitosan microspheres. Microspheres, adhering to a polymerized resin block, were cut with an ultramicrotome and viewed with a scanning electron microscope. Unloaded microspheres exhibited a uniform dense matrix structure while crystals of nifedipine were clearly visible in the drug-loaded microspheres. At 2% drug loading, however, no crystals could be seen in the microspheres indicating that either the drug was molecularly dispersed or dissolved in the matrix at this concentration. This was confirmed by powder X-ray diffractometry studies where no peak due to crystalline nifedipine was observed. At high Span 85 concentration (1.5% w/v), the external surface of the microspheres collapsed, but the internal structure remained dense. When the drug was dispersed in the chitosan solution with stirring during preparation, the entrapment was good and the shape of the crystals was changed. The internal structure of the microspheres following dissolution exhibited the presence of pores.
Chitin↗
Search for lepton flavor violation in K+ decays into a charged pion and two leptons.
A search for lepton flavor violating decays, K+ --> mu+ mu+ pi-, K+ --> e+ e+ pi-, K+ --> pi+ e+ mu-, K+ --> mu+ e+ pi-, and pi0 --> e+ mu-, was performed using the data collected in Experiment E865 at the Brookhaven Alternating Gradient Synchrotron. No signal was found in any of the decay modes. At the 90% confidence level, the branching ratios are less than 3.0x10(-9), 6.4x10(-10), 5. 2x10(-10), 5.0x10(-10), and 3.4x10(-9), respectively.
Journal Article↗
Improved limit on the rate of the decay K+ --> pi(+)&mgr;(+)e(-)
We report results of a search for the lepton-family number violating decay K+-->pi(+)&mgr;(+)e(-) from data collected by experiment E865 in 1996 at the Alternating Gradient Synchroton of Brookhaven National Laboratory. We place an upper limit on the branching ratio at 3.9x10(-11) ( 90% C.L.). Together with results based on data collected in 1995 and an earlier experiment, E777, this result establishes a combined 90% confidence level upper limit on the branching ratio at 2.8x10(-11). We also report a new upper limit on the branching ratio for pi(0)-->&mgr;(+)e(-) of 3.8x10(-10) ( 90% C. L.).
Journal Article↗