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Biomedical subjects

K Kumar

Publications and source records attributed to K Kumar.

At least 19 recordsLinked to original sources
PubMed2005

Antibiotic uptake by plants from soil fertilized with animal manure.

Antibiotics are commonly added to animal feed as supplements to promote growth of food animals. However, absorption of antibiotics in the animal gut is not complete and as a result substantial amounts of antibiotics are excreted in urine and feces that end up in manure. Manure is used worldwide not only as a source of plant nutrients but also as a source of organic matter to improve soil quality especially in organic and sustainable agriculture. Greenhouse studies were conducted to determine whether or not plants grown in manure-applied soil absorb antibiotics present in manure. The test crops were corn (Zea mays L.), green onion (Allium cepa L.), and cabbage (Brassica oleracea L. Capitata group). All three crops absorbed chlortetracycline but not tylosin. The concentrations of chlortetracycline in plant tissues were small (2-17 ng g(-1) fresh weight), but these concentrations increased with increasing amount of antibiotics present in the manure. This study points out the potential human health risks associated with consumption of fresh vegetables grown in soil amended with antibiotic laden manures. The risks may be higher for people who are allergic to antibiotics and there is also the possibility of enhanced antimicrobial resistance as a result of human consumption of these vegetables.

Adsorption↗
PubMed2005

AFM study of mineral wettability with reservoir oils.

Wettability plays a key role in determining fluid distributions and consequently the multiphase flow and transport in petroleum reservoirs. Many crude oils have polar organic components that collect at oil-water interfaces and can adsorb onto the mineral surface if the brine film breaks, rendering the medium oil-wet or mixed-wet. Mica and silica surfaces have been aged with brine and crude oils to induce oil component adsorption. Bulk oil is eventually replaced by water in these experiments by washing with common solvents without ever drying the mineral surface. The organic deposit on the mineral surface is studied by atomic force microscopy in the tapping mode under water. Drying the surface during the removal of bulk oil induces artifacts; it is essential to keep the surface wet at all times before atomic force microscopy or contact angle measurement. As the mean thickness of the organic deposit increases, the oil-water contact angle increases. The organic deposits left behind after extraction of oil by common aromatic solvents used in core studies, such as toluene and decalin, are thinner than those left behind by non-aromatic solvents, such as cyclohexane. The force of adhesion with a probe sphere for minerals aged with just the asphaltene fraction is similar to that of the whole oil. The force of adhesion for the minerals aged with just the resin fraction is the highest of all SARA (saturates, aromatics, resins, and asphaltenes) fractions.

Adsorption↗
PubMed2005

Pin arthrodesis of the wrist--a modified technique.

An intramedullary pin is commonly used for wrist arthrodesis in patients with rheumatoid arthritis. However, pin migration is a recognized complication of this technique. We report the results of wrist fusion in 15 patients using a modified technique with a transverse blocking screw inserted into the metacarpal distal to the intramedullary pin to prevent distal migration and backing out of the intramedullary pin. The procedure is simple to perform, does not add significantly to the operating time and has not been associated with any complications.

Adult↗
PubMed2005

Somatic mutations in the PTCH, SMOH, SUFUH and TP53 genes in sporadic basal cell carcinomas.

BACKGROUND: Basal cell carcinoma (BCC) of the skin is the most common human cancer. The genetic alterations underlying BCC development are only partly understood. OBJECTIVES: To investigate further the molecular genetics of sporadic BCCs, we performed mutation analyses of 10 skin cancer-associated genes in 42 tumours. METHODS: Single-strand conformational polymorphism analysis followed by DNA sequencing was used to screen for mutations in the sonic hedgehog pathway genes PTCH, SMOH, SUFUH and GLI1, in the TP53 tumour suppressor gene, and in the proto-oncogenes NRAS, KRAS, HRAS, BRAF and CTNNB1. Microsatellite markers flanking the PTCH, SUFUH and TP53 loci at 9q22, 10q24 and 17p13, respectively, were studied for loss of heterozygosity (LOH). RESULTS: PTCH mutations were found in 28 of 42 tumours (67%). Microsatellite analysis revealed LOH on 9q22 in 20 of 38 tumours investigated (53%), including 14 tumours with and six tumours without PTCH mutations. SMOH mutations were identified in four of the 42 BCCs (10%) while two tumours demonstrated mutations in SUFUH, including one missense mutation and one silent mutation. None of the BCCs showed LOH at markers flanking the SUFUH locus. Seventeen BCCs (40%) carried TP53 mutations, with only three tumours showing evidence of biallelic TP53 inactivation. TP53 mutations were present in BCCs with and without mutations in PTCH, SMOH or SUFUH. Interestingly, 72% of the TP53 alterations were presumably ultraviolet (UV)-induced transition mutations. In contrast, only 40% of the PTCH and SMOH alterations corresponded to UV signature mutations. No mutations were identified in GLI1, NRAS, KRAS, HRAS, BRAF or CTNNB1. CONCLUSIONS: Our data confirm the importance of PTCH, SMOH and TP53 mutations in the pathogenesis of sporadic BCCs. SUFUH alterations are restricted to individual cases while the other investigated genes do not appear to be important targets for mutations in BCCs.

Adult↗
PubMed2005

Endophytic colonization and in planta nitrogen fixation by a diazotrophic Serratia sp. in rice.

Nitrogen fixing endophytic Serratia sp. was isolated from rice and characterized. Re-colonization ability of Serratia sp. in the rice seedlings as endophyte was studied under laboratory condition. For detecting the re-colonization potential in the rice seedlings, Serratia sp. was marked with reporter genes (egfp and Kmr) using transposon mutagenesis. The conjugants were screened for re-colonization ability and presence of nif genes using PCR. Further, the influence of flavonoids and growth hormones on the endophytic colonization and in planta nitrogen fixation of Serratia was also investigated. The flavonoids, quercetin (3 microg/ml) and diadzein (2 microg/ml) significantly increased the re-colonization ability of the endophytic Serratia, whereas the growth hormones like IAA and NAA (5 microg/ml) reduced the endophytic colonization ability of Serratia sp. Similarly, the in planta nitrogen fixation by Serratia sp. in rice was significantly increased due to flavonoids. The inoculation of endophytic diazotrophs increased the plant biomass and biochemical constituents.

Biomass↗
PubMed2005

Entomological indices of Aedes aegypti at some international airports and seaports of southern India--a report.

Entomological surveys were undertaken at some of the international airports/seaports (Bangalore, Calicut, Chennai, Cochin, Thiruvanathapuram and Vishakapatnam) to find out the breeding prevalence of dengue vector mosquito in diverse breeding containers from 1998 to 2004. Three vector indices (House index, Container index and Breateu index) were used to assess the breeding potential at each airport/seaport. International Health Regulations urged national governments to keep all the international airports/seaports and peripheral areas up to 400 meters free from Aedes aegypti mosquitoes. However, surveys revealed high vector indices at all the airports and seaports. Health authorities of airports/seaports need to take cognizance of these facts and develop action plan for appropriate control measures with emphasis on vector surveillance.

Aedes↗
PubMed2004

Torted and ruptured wandering spleen presenting as a surgical emergency in pregnancy.

Wandering spleen (WS) is characterised by incomplete fixation of the spleen to its supporting linorenal and gastrosplenic ligaments. It can predispose to life-threatening complications due to torsion of its vascular pedicle, splenic infarction, portal hypertension, and haemorrhage. A 27-year-old, 36-week prima gravida underwent emergency caesarean section for tachycardia and hypotension. A healthy baby girl was delivered. However, she remained shocked despite aggressive fluid therapy and intraoperatively it was noted that there was significant intraperitoneal bleeding and the on-call surgical team was summoned. Midline laparotomy revealed a lacerated, infarcted, hypermobile spleen found with free intraperitoneal bleeding. The unsalvageable spleen was resected and the patient went on to make an excellent recovery. The aetiology of WS is contentious. With an increased frequency among multiparous females of reproductive age, some suggest the hormonal effects of pregnancy as contributing factors. Clinical presentations range from an asymptomatic abdominal mass to acute abdominal pain with hypovolaemic shock. WS poses a serious threat to life due to thrombosis, bleeding, or infarction. Ultrasound scan and CT scan are equally effective in the diagnosis. Patients with asymptomatic WS should be treated with elective splenopexy, however, in the acute presentation, splenectomy is the procedure of choice.

Adult↗
PubMed2004

Measurement of the generalized forward spin polarizabilities of the neutron.

The generalized forward spin polarizabilities gamma(0) and delta(LT) of the neutron have been extracted for the first time in a Q2 range from 0.1 to 0.9 GeV2. Since gamma(0) is sensitive to nucleon resonances and delta(LT) is insensitive to the Delta resonance, it is expected that the pair of forward spin polarizabilities should provide benchmark tests of the current understanding of the chiral dynamics of QCD. The new results on delta(LT) show significant disagreement with chiral perturbation theory calculations, while the data for gamma(0) at low Q2 are in good agreement with a next-to-leading-order relativistic baryon chiral perturbation theory calculation. The data show good agreement with the phenomenological MAID model.

Journal Article↗
PubMed2004

Simultaneous exposure of excess fluoride and calcium deficiency alters VDR, CaR, and calbindin D 9 k mRNA levels in rat duodenal mucosa.

Fluoride ingestion reduces intestinal calcium absorption; its molecular basis has not been studied. We studied the mRNA expression of calcium-sensing receptor (CaR), vitamin D receptor (VDR) and calbindin D 9 k (D 9 k) by northern blot analysis in the duodenal mucosa of rats. Weanling pups fed with chow diet containing adequate calcium (0.5% w/w) and drinking water (NaF < 1 ppm) served as controls (Group I) and were studied at 9 and 15 weeks. The pups, born to rats fed with a calcium-deficient diet (0.03%) and excess fluoride water (NaF 50 ppm), were continued on the same diet and water (Group II) until 9 weeks of age. Subsequently, Group II rats were divided into 4 subgroups; 3 subgroups with fluoride free water [II-A adequate calcium, II-B excess calcium (Ca 2%) and II-D calcium deficient], whereas II-C received fluorinated water and adequate calcium diet until 15 weeks. At 9 weeks, as compared to group-I, group-II had decreased VDR (P < 0.001) and D 9 k mRNA (P < 0.001), whereas CaR mRNA levels increased (P < 0.05). At 15 weeks, as compared to group-I, VDR mRNA further reduced in group II-D (P < 0.001) and II-C (P < 0.001), whereas it increased in group II-A. Removal of fluoride ingestion and calcium replenishment increased D 9 k mRNA expression, maximally in adequate calcium group (P < 0.001), while it was further reduced in group II-C (P < 0.001). CaR expression decreased significantly in all the groups. We conclude that excess fluoride reduces the mRNA levels of VDR and D 9 k in the duodenal mucosa of rats, thereby possibly reducing calcium absorption. Calcium supplementation with simultaneous fluoride removal improves their expression.

Animals↗
PubMed2004

Single-capillary Teorell oscillator--studies with nonelectrolytes.

It has been demonstrated that if in a Teorell oscillator, the membrane is replaced by a single capillary, the system behaves much better and becomes easily reproducible. It has also been demonstrated that oscillatory behavior in a Teorell-type setup is not limited to electrolytes; even nonelectrolytes can show oscillations. The only requirement seems to be that the nonelectrolyte should be capable of generating an electrical double layer in the capillary. This is the first report of a Teorell oscillator with a single capillary. Also, oscillations with nonelectrolytes in a Teorell-type setup have not been reported before.

Journal Article↗
PubMed2004

Q2 evolution of the neutron spin structure moments using a 3He target.

We have measured the spin structure functions g(1) and g(2) of 3He in a double-spin experiment by inclusively scattering polarized electrons at energies ranging from 0.862 to 5.058 GeV off a polarized 3He target at a 15.5 degrees scattering angle. Excitation energies covered the resonance and the onset of the deep inelastic regions. We have determined for the first time the Q2 evolution of Gamma(1)(Q2)= integral (1)(0)g(1)(x,Q2)dx, Gamma(2)(Q2)= integral (1)(0)g(2)(x,Q2)dx, and d(2)(Q2)= integral (1)(0)x(2)[2g(1)(x,Q2)+3g(2)(x,Q2)]dx for the neutron in the range 0.1< or =Q2< or =0.9 GeV2 with good precision. Gamma(1)(Q2) displays a smooth variation from high to low Q2. The Burkhardt-Cottingham sum rule holds within uncertainties and d(2) is nonzero over the measured range.

Journal Article↗
PubMed2004

Groundwater quality assessment in different land-use areas of Faridabad and Rohtak cities of Haryana using deviation index.

Physico-chemical parameters were analysed to evaluate the groundwater quality of the two important cities of Haryana, Faridabad and Rohtak, and the pollution status of groundwater was compared using deviation index (DI). Groundwater of both the cities had high alkalinity, hardness, total dissolved solids (TDS) and electrical conductivity. The groundwater of Faridabad showed low fluoride concentration whereas in 74% of groundwater samples of Rohtak the fluoride levels were high. Land use and waste disposal practices were found to have an important effect on groundwater pollution.

Environmental Monitoring↗
PubMed2004

Previously-treated nasopharyngeal carcinoma with cystic lesions in the temporal lobe.

Nasopharyngeal carcinoma is a common malignancy in the Asian Chinese population. First-line treatment consists primarily of radiotherapy and chemotherapy, with salvage surgery if recurrence occurs. Patients with this tumours frequently present years after radiotherapy with symptomatic temporal lobe cystic lesions and a diagnostic problem arises. The possible differential diagnoses include radionecrosis, pyogenic abscesses or tumour recurrence. A series of three cases of cystic temporal lobe lesions, with emphasis on their clinical, radiological and histopathological diagnostic aspects, are presented. The three cases presented consist of radiation necrosis, pyogenic abscess, and a case with both infection with tumour recurrence. The methodology of both clinical and radiological diagnosis are presented.

Adult↗
PubMed2003

Characterization of Plys-proximal morphogenetic genes of transposable bacteriophage Mu.

Late during the bacteriophage Mu lytic cycle, Mu DNA must be matured and packaged from its dispersed integration sites in the host DNA in order to produce progeny virions. Whereas control of late gene transcription in Mu is becoming well understood, less is known about the phage morphogenetic process. To investigate the latter, we cloned and sequenced a approximately 4.3-kb region of the phage DNA beginning just upstream of the leftmost late promoter Plys. Previous mapping of amber mutations had located the lysis (lys) and proposed DNA maturation genes D and E in this region. When the DNA sequence was analyzed, seven potential open reading frames were found. DNA sequence analysis of amber mutations in genes D and E identified the sixth and seventh open reading frames as D and E, respectively. Cloning and expression of this region enabled production of cell-free protein extracts that specifically recognize the phage-encoded packaging sequence (pac), a characteristic exhibited by phage maturation enzymes. In addition, the E protein was found to share homology with the large subunit of many phage DNA maturation enzymes. These results support the hypothesis that D and E encode subunits of the Mu DNA maturation enzyme.

Amino Acid Motifs↗
PubMed2003

Phylogenetic analysis of symbiotic and free-living cyanobacterial cultures using DNA amplification fingerprinting.

DNA amplification fingerprinting (DAF) of 17 cyanobacterial isolates belonging to symbiotic and free-living forms of 6 different genera was done. The dendrogram analysis of 17 cyanobacterial cultures revealed three major clusters. All Westiellopsis cultures formed the first major cluster and their nucleotide relatedness ranged between 71-93%. In the second major cluster, the symbiotic cyanobacterium Anabaena sp dominated and all Anabaena cultures showed 60-75% similarity with each other. Nostoc muscorum is related to Anabaena variabilis by 85% and formed the third major cluster. The dendrogram analysis of cyanobacterial isolates clearly revealed that free-living cyanobacterial cultures were closely related with each other and were diverse from the symbiotic forms.

Cyanobacteria↗