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Biomedical subjects

P Kumar

Publications and source records attributed to P Kumar.

At least 19 recordsLinked to original sources
PubMed2007

Characterization of ionically bound peroxidases from apple (Mallus pumilus) fruits.

Ionically bound peroxidases (POD) were salt extracted from the pulp of four Indian apple varieties, i.e., Golden delicious HP, Golden delicious JK, Red delicious, and Royal delicious. They were precipitated with chilled ethanol. Thermal treatments of partially purified enzymes were given from 40-70 degrees C for 30 minutes. Golden delicious HP peroxidase showed thermostability at 60 degrees C, while three other peroxidases were observed at 50 degrees C. Phenolic compounds (i.e., caffeic acid, ferulic acids, p-coumaric acid, protocatechuic acid) and metal ions (i.e., Cu2+ and Fe2+) activated all apple peroxidases. However, Mn2+ inhibited the peroxidases from Golden delicious HP, Golden delicious JK, and Red delicious, and a substantial increase was observed in Royal delicious peroxidase. Mg2+ inhibited the peroxidases from Golden delicious HP and Red delicious, but marginal activation was reported in peroxidases from Golden delicious JK and Royal delicious. Zn2+ established stimulation in Golden delicious HP and Golden delicious JK peroxidases, but inhibition was observed in peroxidases in Red delicious and Royal delicious.. Methionine, proline, tryptophan, and valine stimulated all four apple peroxidases, but cysteine showed inhibition in Golden delicious JK.

Amino Acids↗
PubMed2006

Imidazolyl-PEI modified nanoparticles for enhanced gene delivery.

The derivatives of polyethylenimine (PEI 25 and 750kDa) were synthesized by partially substituting their amino groups with imidazolyl moieties. The series of imidazolyl-PEIs thus obtained were cross-linked with polyethylene glycol (PEG) to get imidazolyl-PEI-PEG nanoparticles (IPP). The component of hydrophobicity was introduced by grafting the lauryl groups in the maximal substituted IPP nanoparticles (IPPL). The nanoparticles were characterized with respect to DNA interaction, hydrodynamic diameter, zeta potential, in vitro cytotoxicity and transfection efficiency on model cell lines. The IPP and IPPL nanoparticles formed a loose complex with DNA compared to the corresponding native PEI, leading to more efficient unpackaging of DNA. The DNA loading capacity of IPP and IPPL nanoparticles was also lower compared to PEI. The imidazolyl substitution improved the gene delivery efficiency of PEI (750kDa) by nine- to ten-fold and PEI (25kDa) by three- to four-fold. At maximum transfection efficiency, the zeta potential of nanoparticles was positive after forming a complex with DNA. The maximum level of reporter gene expression was mediated by IPPL nanoparticles in both the series. The cytotoxicity, another pertinent problem with cationic polymers, was also negligible in case of IPP and IPPL nanoparticles.

Active Transport, Cell Nucleus↗
PubMed2006

Intraperitoneal tension-free repair of small midline ventral abdominal wall hernias with a Ventralex hernia patch: initial experience in 51 patients.

Midline ventral hernias are common. Tension-free mesh repair of ventral hernias is becoming popular due to the high recurrence rate with conventional techniques. We have used an open intraperitoneal technique using the Bard Ventralex hernia patch in midline ventral hernias (<or=3 cm). Fifty-one patients were treated (34 males and 17 females) with a mean age of 52.4 years (range 18-82). Forty-three patients were day cases. Operative times, analgesic use, overnight hospital stay and postoperative complications were recorded prospectively. The mean operative time was 30 min (range 10-68). Thirty-six patients required mild/moderate postoperative analgesia. Two patients had minor wound infections and one had seroma. There was one recurrence. Our early experience suggests that Ventralex hernia patch repair of small midline ventral hernias can be performed as a day case with minimal postoperative complications.

Adolescent↗
PubMed2006

An efficient and versatile approach for the construction of oligonucleotide microarrays.

A new immobilization chemistry for covalent attachment of phosphorylated oligonucleotides on epoxy-activated glass surface via opening of oxirane ring is described. The proposed strategy results in excellent immobilization efficiency, spot homogeneity, and morphology. The constructed microarray was successfully demonstrated for discrimination of nucleotide mismatches.

Base Pair Mismatch↗
PubMed2006

N-(3-Triethoxysilylpropyl)-6-(N-maleimido)-hexanamide: An efficient heterobifunctional reagent for the construction of oligonucleotide microarrays.

Synthesis of a new heterobifunctional reagent, N-(3-triethoxysilylpropyl)-6-(N-maleimido)-hexanamide (TPMH), for the preparation of oligonucleotide microarrays is described. Its triethoxysilyl function is specific toward virgin glass surface and maleimide function undergoes conjugate addition to 3'- or 5'-thiol-modified oligonucleotides. The construction of microarrays using TPMH has been realized via two routes. In Route A, TPMH was reacted first with 3'- or 5'-thiol-modified oligonucleotide under microwaves, thereby producing oligonucleotide-triethoxysilyl conjugate in 15min, which was then brought in contact with virgin glass microslide, resulting in immobilization of an oligonucleotide sequence. In Route B, immobilization involves generation of maleimide functions on virgin glass surface by the reaction with TPMH, followed by coupling with thiol-modified oligonucleotides under microwaves in 15 min to produce surface-bound oligonucleotides. The microarrays constructed using both routes were analyzed by hybridizing with tetrachlorofluorescein-labeled complementary oligonucleotide. Subsequently, these microarrays were successfully used in the discrimination of single and double nucleotide mismatches based on fluorescence intensity.

Amides↗
PubMed2006

Replacement of an extruded segment of radius after autoclaving and sterilising with gentamicin.

A 10 year-old boy had a traumatic extrusion of 10 cm of the distal radius. The segment of bone was replaced after washing it with providine iodine solution and normal saline, autoclaving and dipping in gentamicin solution for 2 hour. At four and half year's follow-up, there was complete incorporation of the segment with almost full functional recovery. We report this case for its rarity and discuss the treatment.

Bone Nails↗
PubMed2006

Changes in plasma hormones profile and liver function in cows naturally exposed to lead and cadmium around different industrial areas.

The present study was carried out to assess the endocrine status and liver function in adult cows reared in polluted environment around different industrial units in India. The effect on endocrine system was examined by determination of plasma level of thyroid hormones, thyroxin (T4) (n=269) and triidothyronin (T3) (n=269), stress hormone cortisol (n=266), and reproductive hormones such as estradiol (n=84) and progesterone (n=84) in cows (>3 years) reared around different polluted industrial and non-polluted areas. The respective blood lead and cadmium concentration was also determined in all the cows. The mean plasma levels of both T3 and T4 were significantly (P<0.05) higher around lead zinc smelter (2.43+/-0.26 and 41.1+/-2.9nmol/L) and closed lead cum operational zinc smelter (1.81+/-0.16 and 42.4+/-6.2nmol/L), where the mean blood lead level (0.86+/-0.06 and 0.51+/-0.09mug/ml) was also significantly higher than that of cows (0.07+/-0.01mug/ml) from unpolluted areas. Regression analysis of data from 269 cows revealed a significant (P<0.01) positive correlation between the blood lead and plasma T3 (r=0.287) and T4 (r=0.173). The correlation between thyroidal hormones and the blood cadmium concentration (r=-0.079 and -0.48; P>0.05) was not significant. Plasma cortisol level had also a non-significant (P>0.05) correlation (r=-0.092) with blood lead level.However, the mean cortisol level (4.02+/-1.96nmol/L) of cows in phosphate rock mining areas was significantly (P<0.05) higher than that of controls (1.98+/-0.70nmol/L). The mean plasma estradiol level was significantly (P<0.05) higher in cows around closed lead cum operational zinc smelter (47.1+/-19.5pg/ml) than that of the control animals (21.8+/-3.9pg/ml) and in rest of the areas, the difference did not reach the statistical significance (P>0.05). The serum biochemical analysis in 36 cows around lead-zinc smelter with the highest mean blood lead level (0.86+/-0.06mug/ml) amongst all the industrial/urban areas surveyed, and in 15 animals from non-polluted areas revealed a significant positive correlation between blood lead and serum ALT (alanine transaminase) (r=0.688, P<0.01) and AST (aspartate transaminase) (r=0.390, P<0.01) and a negative correlation with serum total lipids (r=-0.337, P<0.05), total protein (r=-0.449, P<0.01) and albumin(r=-0.662, P<0.01). It is concluded from the study that the natural exposure to lead in polluted environments disturbs the endocrine profile and the higher blood lead level alters serum biochemical parameters indicative of liver functions.

Animals↗
PubMed2006

Antioxidant, anticlastogenic and radioprotective effect of Coleus aromaticus on Chinese hamster fibroblast cells (V79) exposed to gamma radiation.

Coleus aromaticus (Benth, Family: Laminaceae), Indian Oregano native to India and Mediterranean, is well known for its medicinal properties. A preliminary study was undertaken to elucidate in vitro free radical scavenging potential and inhibition of lipid peroxidation by C.aromaticus hydroalcoholic extract (CAE). Anti-clastogenic and radioprotective potential of CAE were studied using micronucleus assay after irradiating Chinese hamster fibroblast (V79) cells. CAE at 10, 20, 40, 60, 80, 100 and 120 mug/ml resulted in a dose-dependent increase in radical scavenging ability against various free radicals viz., 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), superoxide anion (O(2)(*-)), hydroxyl (OH(*)) and nitric oxide (NO(*)) generated in vitro. A maximum scavenging potential was noticed at 100 mug/ml and a saturation point was reached thereafter with the increasing doses of CAE. The free radical scavenging potential of the extract was in the order of DPPH > ABTS > Superoxide > Hydroxyl > Nitric oxide. CAE also exhibited a moderate inhibition of lipid peroxidation in vitro, with a maximum inhibition at 60 mug/ml (33%), attaining saturation at higher doses. The extract also rendered protection against radiation induced DNA damage, as evidenced by the significant (P < 0.05) decrease in the percentage of radiation-induced micronucleated cells (MN) and frequency of micronuclei (total). A maximum anticlastogneic effect/ radioprotection was noticed at a very low concentration i.e., 5 mug/ml of CAE, treated 1 h prior to 2 Gy of gamma radiation. A significant (P < 0.0001) anticlastogenic/radioprotective effect was also observed when the cells were treated with an optimum dose of CAE (5 mug/ml) 1 h prior to 0.5, 1, 2 and 4 Gy of gamma radiation compared with the respective radiation control groups. Overall, our results established an efficient antioxidant, anticlastogenic and radioprotective potential of CAE, which may be of great pharmacological importance.

Animals↗
PubMed2006

Structural, spectral, linear and nonlinear optical properties of new nonlinear optical L-histidinium trichloroacetate crystals.

Single crystals of a new histidinium salt: L-histidinium trichloroacetate {abbreviated as LHTCA; [(C(3)N(2)H(4))CH(2)CH(NH(3))(CO(2))](+)CCl(3)COO(-)} were grown by slow evaporation of an aqueous solution at room temperature. The compound crystallizes in a non-centrosymmetric space group P2(1) of monoclinic system with cell parameters a=5.4505(18) A, b=25.769(8) A, c=9.210(2) A and beta=99.98(2) degrees. The vibrational structure of the compound confirms the presence of various functional groups in the molecule. The UV-vis-NIR spectrum shows a good transparency in the whole of the region from ultraviolet to near IR. The Kurtz powder SHG measurement confirms the frequency doubling of the crystal. Thermal behaviour of the crystals has been investigated by DSC analysis. These preliminary results suggest that LHTCA crystal can act as a potential and promising candidate for frequency doubling applications even from the near UV region to the near IR.

Crystallization↗
PubMed2006

Crystallographic identification of an ordered C-terminal domain and a second nucleotide-binding site in RecA: new insights into allostery.

RecA protein is a crucial and central component of the homologous recombination and DNA repair machinery. Despite numerous studies on the protein, several issues concerning its action, including the allosteric regulation mechanism have remained unclear. Here we report, for the first time, a crystal structure of a complex of Mycobacterium smegmatis RecA (MsRecA) with dATP, which exhibits a fully ordered C-terminal domain, with a second dATP molecule bound to it. ATP binding is an essential step for all activities of RecA, since it triggers the formation of active nucleoprotein filaments. In the crystal filament, dATP at the first site communicates with a dATP of the second site of an adjacent subunit, through conserved residues, suggesting a new route for allosteric regulation. In addition, subtle but definite changes observed in the orientation of the nucleotide at the first site and in the positions of the segment preceding loop L2 as well as in the segment 102-105 situated between the 2 nt, all appear to be concerted and suggestive of a biological role for the second bound nucleotide.

Allosteric Regulation↗
PubMed2006

A new synthetic protocol for labeled oligonucleotides, using a chemically cleavable universal linker.

A two-step general method for labeling of synthetic oligonucleotides is described. The protocol employs a cleavable universal linker, 5'-O-(4,4'-dimethoxytrityl)-3'-O-benzoyl-2'-O-(2-cyanoethyl-N,N-diisopropyl)-uridine phosphoramidite, to effect coupling to polymer-bound oligonucleotide chains. Sequentially, coupling with commercially available phosphoramidite reagent of an appropriate label (Biotin, HEX etc.) in an automated DNA synthesizer is carried out. The labeled oligomers, obtained after cleavage and deprotection reactions, are analyzed on RP-HPLC. A distinctive feature of this protocol is the recovery of free oligomers from their labeled analogs under mild conditions. The oligomers obtained are comparable to the corresponding standard oligonucleotides (HPLC).

Biotin↗
PubMed2006

Spectrophotometric estimation of functional groups on microslides for preparation of biochips.

A universal reagent 1-O-(4,4'-dimethoxytrityl)-6-aminohexanol (DTAH) is described for the estimation of surface-bound functionalities (epoxy, aldehyde, and carboxyl) required for preparation of oligonucleotide arrays (biochips). The method involves the reaction of universal reagent DTAH with surface-bound functionality under microwaves for 10 min, followed by washings to remove the excess reagent. In the subsequent step, a weighed amount of DTAH-treated surface is exposed to acid to liberate 4,4'-dimethoxytrityl cation, which is measured at 505 nm to determine the functional group loading on the surface.

Aldehydes↗
PubMed2006

Effect of temporal synergism of neural oscillations on photorefractoriness in Japanese quail (Coturnix coturnix japonica).

Circadian rhythms in many metabolic functions including neural (transmitters) and hormonal secretion appear to change with physiological condition. It is also reported that seasonal changes in photoperiodism/reproduction and other metabolic conditions may result from a temporal interaction of circadian neural oscillations that change seasonally. To test this hypothesis, the present study was designed to study the effect of temporal synergism of two neural oscillations (serotonin and dopamine) on relative photorefractoriness of Japanese quail. Serotonin and dopamine precursor drugs (5-HTP, 5-hydroxytryptophan and L-DOPA, L-dihydroxyphenylalanine) were administered (intraperitonially 5 mg/100 g body weight) at six different time intervals of 0, 4, 8, 12, 16 and 20 hr in sexually mature quail (>12 weeks old). The birds of control group received two daily injections of normal saline. The treatment was given for 13 days in continuous condition of light and then the quail were shifted to intermediate daylength (LD 13.5:10.5 for experiment 1) and short daylength (LD 8:16 for experiment 2). Six weeks following treatment, birds in intermediate daylength showed regressed cloacal gland and testicular activity except in 12-hr group, which exhibited gonadostimulatory condition. But birds of all the groups in short daylength showed complete regression of cloacal gland after 4 weeks of the treatment. In experiment 3, reproductively quiescent relative photorefractory quail maintained under intermediate daylength (LD 13.5:10.5) received 13 daily injections of 5-HTP and L-DOPA at the interval of 12 hr. At 6 weeks post-treatment, it was observed that unlike cloacal gland of control quail, which remained regressed, that of 12-hr quail showed significant development. These findings indicate that 12-hr temporal interaction of 5-HTP and L-DOPA administration maintained reproductive system in stimulated condition and prevented reproductive regression in photorefractory quail, but did not prevent the onset of scotosensitivity. It is concluded that the 12-hr temporal relationship of circadian serotonergic and dopaminergic oscillations not only eliminates photorefractoriness but may also re-establish photosensitivity in relative photorefractory quail. These findings suggest the regulatory role of neural oscillations and their temporal interaction in the regulation of neuroendocrine-gonadal axis with special reference to photosensitivity/refractoriness.

5-Hydroxytryptophan↗
PubMed2006

Sero-epidemiological study of kala-azar in a village of Varanasi district, India.

OBJECTIVE: To evaluate five kala-azar serological tests for field use. METHOD: Serological survey in Pandit Ka Purva village in Varanasi district, India, using Sia water test, aldehyde test, direct agglutination test (DAT), micro-enzyme-linked immunosorbent assay (ELISA) and dot-ELISA. RESULTS: The total population of the village was 518, 67 of whom showed typical clinical and parasitological features of kala-azar, including seven who died. The age distribution of kala-azar cases showed significant differences, being highest among the 45-54-year age group. The disease was more prevalent among males. Serum samples were collected from 498 persons (96% of total population) including 67 kala-azar cases and 40 disease controls (malaria, TB, leprosy, typhoid). Ten 10 serum samples from healthy controls living in endemic area were also collected. The test sensitivities were: Sia water test, 85.0%; aldehyde test, 62.7%; DAT, 94.0%; micro-ELISA, 91.0% and dot-ELISA, 97.0%. The test specificities were: Sia water test 92.5%, aldehyde test, 93.2%, DAT, 96.7; micro-ELISA, 97.6% and dot-ELISA, 98.4%. CONCLUSION: The dot-ELISA is highly sensitive and specific, cheap, and easy to interpret with the naked eye, making it a powerful screening test for the surveillance and diagnosis of Indian kala-azar at field level.

Adolescent↗