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Pankaj Sharma

Publications and source records attributed to Pankaj Sharma.

33 records · Page 2Linked to original sources
PubMed2003

Herbicidal, plant growth inhibitory, and cytotoxic activities of bismuthines containing aromatic heterocycles.

This work presents the herbicidal and plant growth regulatory activities of tertiary bismuthines containing heterocyclic aromatic rings of the general formula (2-C(4)H(3)X)(3)Bi, where X = S (3), O (1), or NMe (2). Toxicity against Artemia salina and herbicidal activity on Lactuca sativa, Trifolium pratense, and Lolium multiflorum were tested. In addition to the effects on mitochondrial respiration obtained from roots of Phaseolus vulgaris, these compounds also demonstrated partial radical scavenging properties against 2,2-diphenyl-1-picrylhydrazyl (DPPH). The furyl substituent is the most important structural requirement for the activity measurements observed in this study.

Animals↗
PubMed2003

Crystal structure of trans-dibromobis(triphenylphosphine)platinum(II).

Crystal structure of trans-dibromobis(triphenylphosphine)platinum(II) was determined by X-ray-crystallography. The complex crystallizes on an inversion center in distorted square planar coordination around platinum with triphenylphosphine ligands in trans positions to each other and with two molecules of dichloromethane as solvate.

Journal Article↗
PubMed2002

Tracing the history of nuclear releases: determination of 129I in tree rings.

Concentrations of the long-lived radioisotope 1291 were measured in dated tree rings in order to determine whether the distribution of this isotope reflects the history of nuclear deposition. 129I concentrations and 129I/127I ratios were analyzed in tree rings and bark samples from four trees at West Valley, NY, and from one tree at Rochester, NY. West Valley was the site of short-lived nuclear fuel reprocessing activities (1966-1972), while Rochester, located 115 km to the northeast, provided a regional control site for the study. The selected trees reflect different modes of fluid and nutrient transport in trees, with three species of ring-porous trees (elm, oak, and locust), one semidiffuse (cherry), and one diffuse-porous tree (maple). The results show that 1291 levels in ring-porous trees, in which xylem or hydrologic tissue is localized in the outermost growth ring, are generally well correlated with the expected 1291 deposition pattern for the region. In contrast, tree rings of the more common semidiffuse to diffuse-porous wood, where xylem is disseminated throughout the trunk, show a less well developed 129I signal, probably due to the transport of iodine ions across annual rings. Iodine concentrations in the tree rings range from 0.04 to 2 mg/kg, 129I/127I ratios from 6 x 10(-10) to 3.8 x 10(-6). Tree bark and the outermost rings show significantly higher 129I concentrations than the wood of the trunk. The 129I/127I ratios for bark are very similar to values obtained for surface soil and water at the two localities, while inner rings have ratios similar to those in deeper layers of the soil, reflecting different pathways for 129I uptake and the differences in ambient 1291 levels between the atmosphere and deep soil. Although ring porous trees preserve the depositional pattern of nuclear releases, rings older than or close to the onset of the nuclear age have 129I/127I ratios significantly above the preanthropogenic level, suggesting that even in these trees some redistribution of 129I occurs throughout the trunk. Our results indicate that growth rings from ring-porous wood are useful in time-series analyses of regional 129I deposition, yielding reliable information on relative changes in 129I concentrations but requiring caution in the reconstruction of absolute ambient concentrations during any given time.

Air Movements↗
PubMed2002

IL-13R(alpha)2, a decoy receptor for IL-13 acts as an inhibitor of IL-4-dependent signal transduction in glioblastoma cells.

Interleukin (IL)-4 and IL-13 share the type II IL-4 receptor for cell signaling. We show that despite expressing the necessary signaling components, glioblastoma cells failed to respond to either IL-4 or IL-13. This was in part because of the expression of a high-affinity IL-13-binding transmembrane protein IL-13R(alpha)2 that inhibited IL-13-mediated Stat6 activation by acting as a decoy receptor. In contrast, normal human astrocytes that did not express the IL-13R(alpha)2 gene efficiently induced Stat6 activation in response to both IL-4 and IL-13. Transient expression of the IL-13R(alpha)2 transgene in nonexpressing heterologous cells inhibited not only IL-13- but also IL-4-mediated signal transduction and Stat6-responsive gene expression. The inhibition was likely mediated through the physical interaction between the short intracellular domain of the IL-13R(alpha)2 protein and the cytoplasmic domain of the IL-4R(alpha) chain that harbors the Stat6 docking sites. Thus, IL-13R(alpha)2 acts as an inhibitor of IL-4-dependent signal transduction pathways via a novel mechanism that is independent of ligand binding.

3T3 Cells↗
PubMed2002

Combined extracapsular cataract extraction with ahmed glaucoma valve implantation in phacomorphic glaucoma.

PURPOSE: To report a retrospective analysis of a combined procedure of extracapsular cataract extraction (ECCE) with heparin surface modified (HSM) posterior chamber intraocular lens (PCIOL) implantation along with primary Ahmed glaucoma valve (AGV) implantation in an attempt to optimize visual acuity gains and intraocular pressure (IOP) control in patients with phacomorphic glaucoma. METHODS: ECCE with HSM PC IOL and AGV implantation was performed through two separate incisions in 15 patients diagnosed with phacomorphic glaucoma. Postoperative improvement in visual acuity and IOP control were monitored. RESULTS: A steady control of IOP was maintained in all patients with minimum anti-glaucoma medications. The average visual acuity was approximately 6/24 at 3 months. CONCLUSION: Superior preoperative IOP control and a shorter phacomorphic attack resulted in better postoperative vision. The successful maintenance of IOP within the desired range in this study suggests that the procedure should be performed under similar conditions.

Adult↗
PubMedDate not supplied

Homocysteine and stroke: evidence on a causal link from mendelian randomisation.

BACKGROUND: Individuals homozygous for the T allele of the MTHFR C677T polymorphism have higher plasma homocysteine concentrations (the phenotype) than those with the CC genotype, which, if pathogenetic, should put them at increased risk of stroke. Since this polymorphism is distributed randomly during gamete formation, its association with stroke should not be biased or confounded. We investigated consistency between the expected odds ratio for stroke among TT homozygotes, extrapolated from genotype-phenotype and phenotype-disease studies, and the observed odds ratio from a meta-analysis of genotype-disease association studies. METHODS: We searched MEDLINE and EMBASE up to June, 2003, for all relevant studies on the association between homocysteine concentration and the MTHFR polymorphism, and until December, 2003, for those on the association between the polymorphism and the risk of stroke. Pooled odds ratios and 95% CI were calculated by random-effects and fixed-effects models. Consistency between expected and observed odds ratios was assessed by interaction test. FINDINGS: 111 studies met the selection criteria. Among 15635 people without cardiovascular disease, the weighted mean difference in homocysteine concentration between TT and CC homozygotes was 1.93 micromol/L (95% CI 1.38 to 2.47). The expected odds ratio for stroke corresponding to this difference based on previous observational studies was 1.20 (1.10 to 1.31). In our genetic meta-analysis (n=13928) the odds ratio for stroke was 1.26 (1.14 to 1.40) for TT versus CC homozygotes, similar to the expected odds ratio (p=0.29). Consistency between the odds ratios was preserved in analyses by age-group, ethnic background, and geographical location. INTERPRETATION: The observed increase in risk of stroke among individuals homozygous for the MTHFR T allele is close to that predicted from the differences in homocysteine concentration conferred by this variant. This concordance is consistent with a causal relation between homocysteine concentration and stroke.

Causality↗
PubMedDate not supplied

Foxy, a designer tryptamine hallucinogen.

Foxy is slang for 5-methoxy-N,N-diisopropyltryptamine. It has hallucinogenic properties, similar to other tryptamine compounds, and is mildly euphoric. This case report describes a 21-year-old Caucasian man who ingested a pill called Foxy containing an unknown amount of drug. He was observed in hospital for 2 h, during which time he had mild hallucinations and could not move his limbs. A urine sample was collected approximately 4 h after drug ingestion. The patient was then discharged with no follow up assessment. The 5-methoxy-N,N-diisopropyltryptamine was identified in the urine by gas chromatography-mass spectrometry. Standards prepared from the pure material were used in the identification. Quantitative analysis using the same analytical technique resulted in a urinary concentration of 1.7 micro g/mL. Through oxidative deamination, the metabolite, 5-methoxy-indole acetic acid, was formed. It was identified in the urine, and the concentration was determined to be 1.3 micro g/mL using gas chromatography-mass spectrometry. Two other compounds were discovered in the urine sample as a result of a routine drug screen. From their mass spectra, they were tentatively identified as 5-methoxy-N-isopropyltryptamine and 5-methoxy-N,N-diisopropyltryptamine-N'-oxide.

5-Methoxytryptamine↗
PubMedDate not supplied

Effect of levodopa and carbidopa in human amblyopia.

BACKGROUND: To assess the role of continuous therapy for 3 weeks with levodopa and carbidopa in the management of human amblyopia in children and adults. METHOD: There were 88 amblyopic eyes of 82 subjects included in this double masked randomized prospective clinical trial. Levodopa and carbidopa combination in 2 different dosage schedules were given to both adults and children. The response was monitored of the improvement in visual acuity, contrast sensitivity, and visually evoked potentials. RESULT: Patients receiving higher dosages of levodopa and carbidopa in both adults and children showed a better response to treatment. However, the effect did not last beyond 9 weeks of stopping treatment. CONCLUSION: Though levodopa and carbidopa therapy may not be able to ameliorate amblyopia on its own on a long-term basis, it may be considered nonetheless to be an important adjunct to conventional therapy because it may improve patient compliance for occlusion by improving visual acuity in the amblyopic eye. Thus, it offers promise of improving the functional outcome in these cases. However, longer follow-up trials are needed to substantiate these conclusions.

Adolescent↗
PubMedDate not supplied

Optic nerve cysticercosis.

Optic nerve cysticercosis is rare but causes significant visual morbidity. A high index of suspicion is warranted for patients in endemic areas who present with sudden vision loss. Visual morbidity can be prevented by early imaging studies and therapeutic interventions.

Child↗
PubMedDate not supplied

A comparative study of small incision trabeculectomy avoiding tenon's capsule with conventional trabeculectomy.

BACKGROUND AND OBJECTIVE: The purpose of this study was to compare the results of small incision trabeculectomy (SIT) avoiding Tenon's capsule vis-à-vis conventional trabeculectomy, and find a safe, effective alternative to conventional trabeculectomy with or without pharmacological wound modulation. PATIENTS AND METHODS: A controlled prospective study was conducted on 80 consecutive open-angle glaucoma patients requiring glaucoma filtration surgery. They were divided into two groups: Group I (n = 40): patients undergoing conventional trabeculectomy; and Group II (n = 40): patients undergoing limbal approach SIT. Patients were followed up serially for a minimum of 12 months and their intraocular pressure was monitored. Success of the procedure was defined as an intraocular pressure (IOP) <22 mm Hg with no additional antiglaucoma medication or surgery, and achieving at least a 30% reduction from the initial IOP at which optic disc cupping and/or visual field changes occurred. RESULTS: A significant fall (P <0.0001) in the final mean IOP was present in both groups at all time intervals in comparison to their preoperative values. The final mean intraocular pressure achieved with conventional trabeculectomy was 18.90 +/- 4.86 mm Hg versus 16.60 +/- 5.93 mm Hg with SIT. The final success rate of 90% was obtained with SIT vs 80% with conventional trabeculectomy. No major complications were encountered with either procedure although complications such as shallow anterior chamber and progression of cataractogenesis were seen more often in patients undergoing conventional trabeculectomy. CONCLUSION: Small incision trabeculectomy avoiding Tenon's capsule is a low-cost and safe alternative to conventional trabeculectomy that effectively reduces IOP in 90% of cases. The use of a small 2.5 mm limbal incision, which obviates the dissection of Tenon's capsule and absence of any major complication, suggests that this procedure be used more often in glaucomatous eyes needing filtering surgery.

Adult↗
PubMedDate not supplied

Tuberculous osteomyelitis and optic neuritis.

This case report describes a rare instance of bilateral optic papillitis associated with histologically and bacteriologically proven tubercular osteomyelitis of the right sphenoid and temporal bone of the orbit in a 30-year-old woman. This case also highlights the usefulness of computerized axial tomography of the orbits, skull, and paranasal sinuses to evaluate optic neuritis and its pathophysiology in the event of no obvious cause or contributing systemic disease.

Adult↗