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R Kumar

Publications and source records attributed to R Kumar.

At least 37 records · Page 2Linked to original sources
PubMed2006

Improved constraints on D0-D0 mixing in D0 --> K+ pi- decays from the Belle detector.

We report the results of a search for D0-D0 mixing in D0 --> K+ pi- decays based on 400 fb(-1) of data accumulated by the Belle detector at KEKB. Both assuming CP conservation and allowing for CP violation, we fit the decay-time distribution for the mixing parameters x and y, as well as for the parameter R(D), the ratio of doubly Cabibbo-suppressed decays to Cabibbo-favored decays. The 95% confidence level region in the (x'2,y') plane is obtained using a frequentist method. Assuming CP conservation, we find x'2 < 0.72 x 10(-3) and -9.9 x 10(-3) < y' < 6.8 x 10(-3) at the 95% confidence level; these are the most stringent constraints on the mixing parameters to date. The no-mixing point (0,0) has a confidence level of 3.9%. Assuming no mixing, we measure R(D) = (0.377 +/- 0.008 +/- 0.005)%.

Journal Article↗
PubMed2006

CRIPak, a novel endogenous Pak1 inhibitor.

p21-activated protein kinase 1 (Pak1) plays an important role in several cellular processes, including cytoskeleton reorganization, promotion of the cell survival, and the estrogen receptor (ER) signaling. Pak1 expression and activity is deregulated in a number of cancers. Pak1 is activated by a variety of physiological signals; however, less is known about the negative regulators of Pak1. Here, we report a negative regulator of Pak1. By performing a yeast two-hybrid screen of a mammary gland library, we identified cysteine-rich inhibitor of Pak1 (CRIPak) as a novel Pak1-interacting protein. We found that CRIPak is an intronless gene that localized to chromosome 4p16.3. It contains 13 zinc-finger domains and has three trypsin inhibitor-like, cysteine-rich domains and is widely expressed in a number of human cells and tissues. We further found that CRIPak interacted with Pak1 through the N-terminal regulatory domain and inhibited Pak1 kinase in both in vitro and in vivo assays. CRIPak inhibited Pak1-mediated LIM kinase activation and enhancement of ER transactivation. Conversely, selective inhibition of the endogenous CRIPak resulted in an increased Pak1 activity, and consequently, increased cytoskeleton remodeling and Pak1-mediated ER transactivation activity. The hormonal stimulation of cells enhanced CRIPak expression and promoted its colocalization with ER in the nuclear compartment. Our findings suggest that CRIPak is a novel negative regulator of the Pak1 and has a role in the modulation of Pak1-mediated ER transactivation in breast cancer cells.

Amino Acid Sequence↗
PubMed2006

Controls on quartz silt formation by crystalline defects.

Silt composed predominately of quartz occurs abundantly in the sedimentary material found in deposits worldwide. Its origin is still the subject of many debates, but one acknowledged source is due to glacial grinding. To examine this problem and test the apparent contradictory evidence in the literature, a series of experiments were performed. In these experiments, the Bromhead ring shear apparatus was used as it can simulate glacial grinding due to its uninterrupted shearing action; hence, it provides an effective reproduction of glacial grinding. Experiments conducted on unweathered sand-sized vein quartz produced little silt, while use of sand from a sedimentary deposit, Leighton Buzzard sand, produced plentiful silt. Experimental results suggest that there is an internal mineralogical control on the formation of quartz silt particles. It is argued that the processes involved in the formation of quartz introduce defects (Moss defects) into the low-quartz crystal structure, demonstrated by the presence of peaks in the particle size curve around 20 microm. This indicates that there is a lithological control for the silt yielded under weathering, and this could explain why a pronounced mode at around 20-60 micirom is commonly observed in silts, such as loess.

Geologic Sediments↗
PubMed2006

New temperate DNA phage BcP15 acts as a drug resistance vector.

This study was designed to determine the role of a new temperate DNA phage BcP15 in relation to drug resistance. The multidrug resistant Shigella flexneri NK1925 was isolated from a patient of Infectious Diseases Hospital, Kolkata, India. This strain contained five plasmids ranging in size from 3 to 212 kb. After curing of five plasmids, this strain became sensitive to antibiotics. A plasmidless multidrug-resistant strain Burkholderia cepacia DR11 was isolated during the survey of microorganisms from coastal waters of deltaic Sunderbans. This strain always released a temperate phage BcP15 into culture supernatant. Turbid plaque formation was observed on the lawn of a plasmidless version (Pl(-)35) of Shigella flexneri NK1925. A few distinct clones (Pl(-)35R) appeared within the region of each plaque after 18 h incubation. S. flexneri NK1925, Pl(-)35, and Pl(-)35R clones showed the same PFGE band pattern of XbaI-digested chromosomal DNA. However, Pl(-)35R clones were resistant to co-trimoxazole, trimethoprim, and eryth- romycin, to which B. cepacia DR11 was also resistant. Southern hybridization results indicated that these three antibiotic resistances in Pl(-)35R clones were due to a BcP15 phage lysogen in the Pl(-)35 version of S. flexneri NK1925.

Anti-Bacterial Agents↗
PubMed2006

On the kinetics of apatite growth on substrates under physiological conditions.

Derived from reaction kinetics, a simple but useful method, based on "apatite forming capacity" or AFC of solutions mimicking blood plasma, is proposed to decipher the rate of calcium phosphate mineralization. Apatite growth rate constants were calculated using this method for a model composite surface varying the volume fraction of synthetic hydroxyapatite (HA) in a polymer matrix. Previously reported data for mineralized surfaces on Ta, Ti, and its alloys are also analyzed similarly and compared. Utilizing the growth rate constant, the bioactivity of the materials was indexed in vitro. Complementarily, semiempirical quantum mechanical calculation (ZINDO method) showed that the interaction of cations with TRIS-hydroxymethyl aminomethane molecules in the solution is stronger than that with the polymer substrate considered, but weaker than hydrated Ti and TiO(2) surfaces. This analysis then quantifies for example the extent of polymer inertness and the "bioactivity" of alkali treated Ti. The growth rate constants for the model materials prepared in this work are explained on the basis of localized dissolution of HA, the amount of which simply increases with increasing volume fraction of HA in the composite.

Apatites↗
PubMed2006

Enterococcus faecalis-mediated biomineralized biofilm formation on root canal dentine in vitro.

Enterococcus faecalis is the most predominant bacteria in teeth with failed root canal therapy and is found to survive harsh conditions prevailing in the root canals of endodontically treated teeth. This study aims to investigate the interaction between E. faecalis and root canal dentine substrate. Towards this end, tooth specimens were prepared and divided into two groups. The tooth specimens in group 1 were incubated with E. faecalis for periods of 2-, 4-, and 6-week intervals and the chemical composition of the biofilm was determined using X-ray diffraction and Fourier transform infrared (FTIR) spectroscopy. The tooth specimens in group 2 were incubated with E. faecalis for a period of 6 weeks and the topography and ultrastructure of the biofilm were examined using scanning electron microscopy (SEM), light microscopy, and laser confocal scanning microscopy. The sediments formed from the bacterial interaction on the dentine (in group 1) were also examined by SEM and FTIR. These experiments highlighted different stages in the interaction of E. faecalis with root canal dentine. Further, a bacterial-induced apatite reprecipitation on mature biofilm was also observed. This ability of E. faecalis to form such calcified biofilm on root canal dentine may be a factor that contributes to their persistence after endodontic treatment.

Biocompatible Materials↗
PubMed2006

Pseudomonas aeruginosa inducing rice resistance against Rhizoctonia solani: production of salicylic acid and peroxidases.

Three isolates of Pseudomonas aeruginosa were used for seed treatment of rice; all showed plant growth promoting activity and induced systemic resistance in rice against Rhizoctonia solani G5 and increased seed yield. Production of salicylic acid (Sal) by P. aeruginosa both in vitro and in vivo was quantified with high performance liquid chromatography. All three isolates produced more Sal in King's B broth than in induced roots. Using a split root system, more Sal accumulated in root tissues of bacterized site than in distant roots on the opposite site of the root system after 1 d, but this difference decreased after 3 d. Sal concentration 0-200 g/L showed no inhibition of mycelial growth of R. solani in vitro, while at > or =300 g/L it inhibited it. P. aeruginosa-pretreated rice plants challenged inoculation with R. solani (as pathogen), an additional increase in the accumulation of peroxidase was observed. Three pathogenesis-related peroxidases in induced rice plants were detected; molar mass of these purified peroxidases was 28, 36 and 47 kDa. Purified peroxidase showed antifungal activity against phytopathogenic fungi R. solani, Pyricularia oryzae and Helminthosporium oryzae.

Antibiosis↗
PubMed2006

Can dose reduction to one parotid gland prevent xerostomia?--A feasibility study for locally advanced head and neck cancer patients treated with intensity-modulated radiotherapy.

AIMS: Dryness of the mouth is one of the most distressing chronic toxicities of radiation therapy in head and neck cancers. In this study, parotid function was assessed in patients with locally advanced head and neck cancers undergoing intensity-modulated radiotherapy (IMRT) with or without chemotherapy. Parotid function was assessed with the help of a questionnaire and parotid scintigraphy, especially with regards to unilateral sparing of the parotid gland. MATERIALS AND METHODS: In total, 19 patients were treated with compensator-based IMRT between February 2003 and March 2004. The dose to the clinical target volume ranged between 66 and 70 Gy in 30-35 fractions to 95% of the isodose volume. Ipsilateral high-risk neck nodes received an average dose of 60 Gy and the contralateral low-risk neck received a dose of 54-56 Gy. Eight of 19 patients also received concomitant chemotherapy. RESULTS: Subjective toxicity to the parotid glands was assessed with the help of a questionnaire at 0, 3 and 6 months and objective toxicity was assessed with parotid scintigraphy at 0 and 3 months. The mean dose to the ipsilateral parotid gland ranged from 19.5 to 52.8 Gy (mean 33.14 Gy) and the mean dose to the contralateral gland was 11.1-46.6 Gy (mean 26.85 Gy). At a median follow-up of 13 months, 9/19 patients had no symptoms of dryness of the mouth (grade I), 8/19 had mild dryness of the mouth (grade II) and only 2/19 had grade III xerostomia, although the parotid gland could only be spared on one side in most of the patients. CONCLUSIONS: Minimising the radiation dose to one of the parotid glands with the help of IMRT in patients with advanced head and neck cancers can prevent xerostomia in most patients and parotid scintigraphy is a useful method of documenting xerostomia.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2006

Fludarabine, cyclophosphamide and horse antithymocyte globulin conditioning regimen for allogeneic peripheral blood stem cell transplantation performed in non-HEPA filter rooms for multiply transfused patients with severe aplastic anemia.

Multiply transfused patients of severe aplastic anemia are at increased risk of graft rejection. Five such patients underwent peripheral blood stem cell transplantation from HLA-identical siblings with a fludarabine-based protocol. The conditioning consisted of fludarabine 30 mg/m(2)/day x 6 days, cyclophosphamide 60 mg/kg/day x 2 days and horse antithymocyte globulin (ATG) x 4 days. Two different ATG preparations were used: ATGAM (dose 30 mg/kg/day x 4 days) or Thymogam (dose 40 mg/kg/day x 4 days). Engraftment: median time to absolute neutrophil count (ANC) >0.5 x 10(9)/l was 11 days (range: 8-17) and median time to platelet count >20 x 10(9)/l was 11 days (range: 9-17). At a median follow-up of 171 days (range: 47-389), there has been no graft rejection and all patients are in complete remission. Acute GVHD (grade 1) occurred in one patient only. Chronic GVHD developed in two patients (extensive in one and limited in another). The transplants were performed in non-HEPA filter rooms. In only one patient, systemic antifungal therapy (voriconazole) was used. The use of Thymogam brand of ATG for conditioning is being reported for the first time. Our experience suggests that this fludarabine-based protocol allows rapid sustained engraftment in high-risk patients without significant immediate toxicity.

Adolescent↗
PubMed2006

Endoscopic management of liver abscesses and cysts that communicate with intrahepatic bile ducts.

BACKGROUND AND STUDY AIMS: The formation of a communication between liver abscesses or cysts and intrahepatic bile ducts is an uncommon cause of significant bile leak. Surgical management of biliary fistulas is associated with high morbidity and mortality. We performed a prospective study of endoscopic management of this type of biliary fistula. PATIENTS AND METHODS: We studied 26 patients who had either liver abscesses or hepatic cysts that had ruptured into the intrahepatic bile ducts. The presence of a biliary fistula was suspected by jaundice and/or by the appearance of bile in percutaneous drainage effluent from a liver abscess and was confirmed by endoscopic retrograde cholangiopancreatography. Once the route of the fistula between the liver abscess or cyst and the intrahepatic bile duct had been defined by cholangiography, patients underwent treatment by sphincterotomy, and either biliary stenting or nasobiliary drainage. Nasobiliary drains or biliary stents (both 7 Fr) were placed according to standard techniques. Nasobiliary drains were removed when bile leakage stopped and closure of the fistula was confirmed by cholangiography; stents were removed after an interval of 4-6 weeks. RESULTS: Of a total of 525 patients with hepatic abscesses or cysts who were seen over a 5-year period, there were 26 patients who developed a demonstrable communication between liver abscesses (n = 20; 16 amebic, four pyogenic) or hydatid cysts (n = 6) and intrahepatic bile ducts (right intrahepatic bile ducts in 22 patients, left intrahepatic bile ducts in four patients). We performed either sphincterotomy with insertion of a nasobiliary drain (n = 20) or sphincterotomy with biliary stenting (n = 6). The fistulas healed in all patients after a mean time of 4 days (range 2-20 days) after endoscopic treatment. We were able to remove the nasobiliary drainage catheters and stents 6-34 days after their placement. CONCLUSIONS: In this case series, endoscopic therapy appears to be an effective mode of treatment for biliary fistulas complicating liver abscesses and cysts.

Adult↗
PubMed2006

Antifertility activity of Piper longum Linn. in female rats.

The crude extract, its different fractions and the major pure compound from the active fraction of the powdered fruits of Piper longum were studied for the antifertility effect in female rats. The crude extract and its hexane fraction exhibited 100 and 86% efficacy respectively (days 1-7 post-coitum (p.c.) schedule). On the other hand, 1-butanol soluble, 1-butanol insoluble and chloroform fractions were inactive.

Abortifacient Agents↗
PubMed2006

18F-fluorodeoxyglucose-positron emission tomography in evaluation of primary cutaneous lymphoma.

BACKGROUND: The diagnosis of primary cutaneous lymphoma (PCL) is currently based on clinical and histological findings and/or relatively invasive procedures such as bone marrow and fine-needle lymph node biopsies. Although computed tomography (CT) is a noninvasive imaging modality that is widely used for staging in patients with lymphoma, it cannot provide information about malignant cutaneous lesions. OBJECTIVES: To investigate the usefulness of (18)F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) in the management of PCL. METHODS: We retrospectively analysed 31 FDG-PET studies in 19 patients with PCL [15 T-cell non-Hodgkin lymphoma (NHL) and four B-cell NHL]. There were 10 men and nine women (age range 23-84 years, mean +/- SD 54 +/- 16). Eleven FDG-PET studies were performed for initial staging and 20 FDG-PET studies were performed for restaging following therapy. Results of FDG-PET were compared with those of CT. Clinical parameters and/or biopsy results of lesions served as reference for the accuracy of PET and CT in evaluating local and metastatic lesions. RESULTS: For the initial staging, FDG-PET had a sensitivity of 82% for the evaluation of local disease and 80% for the detection of distant metastasis. The corresponding values for CT were 55% and 100%, respectively. For restaging of cutaneous lymphoma, FDG-PET had a sensitivity of 86% and specificity of 92% for local recurrence/residual disease and a sensitivity of 100% and specificity of 100% for distant metastasis. The corresponding values for CT were 50% and 83% for local recurrence/residual disease and 100% and 67% for distant metastasis. CONCLUSIONS: FDG-PET has a potential value for initial staging and restaging following therapy in patients with PCL. FDG-PET has higher diagnostic value than CT in the detection both of local disease and distant metastasis.

Adult↗
PubMed2006

Case-control study in basal cell carcinoma of the skin: single nucleotide polymorphisms in three interleukin promoters pre-analysed in pooled DNA.

BACKGROUND: Basal cell carcinoma (BCC) is one of the most common neoplasms in the world. Development of BCC is associated with environmental factors (especially sun exposure) as well as heritable factors. OBJECTIVES: To analyse three single nucleotide polymorphisms (SNPs) in the promoter regions of interleukin (IL) genes in genomic DNA from 527 cases of BCC and 530 matched controls and to examine if DNA pooling is a useful method on which to base decisions regarding further SNP analysis. METHODS: The SNPs analysed were IL6-597, IL10-1082 and IL1B-511. The SNPs were first analysed from pooled DNA and afterwards from individual samples. The DNA pools resulted from a division of the samples into cases and controls, female and male, and three age groups. In these pools the allele frequencies were estimated by two methods, real-time polymerase chain reaction with allele-specific primers, and quantitative sequencing. RESULTS: No significant association was found when the allele frequencies in cases and controls were compared. However, by analysis of the individual genotypes we found SNP IL6-597 G/A to be significantly associated with BCC risk (P =0.007). Hereby the heterozygous genotype 'GA' had a protective effect (odds ratio 0.64, 95% confidence interval 0.49-0.84). No significant association was found for IL10-1082 and IL1B-511. CONCLUSIONS: The association of SNP IL6-597 with BCC could be found only by individual genotyping, but would have been missed if only data from the pooling analysis had been known.

Aged↗
PubMed2006

Osteoma cutis in pseudohypoparathyroidism.

Osteoma cutis is the formation of normal bone in the skin. Primary osteoma cutis occurs de novo, whereas the secondary type develops in association with the underlying inflammatory, tumorous or traumatic conditions. Primary osteoma cutis is also associated with Albright's hereditary osteodystrophy (AHO), which can include hypocalcaemic-type pseudohypoparathyroidism (also known as pseudohypoparathyroidism type Ia) or normocalcaemic-type pseudohypoparathyroidism (also known as pseudopseudohypoparathyroidism). We describe a case of osteoma cutis in a 7-year-old boy who had cutaneous, biochemical and phenotypic features of pseudohypoparathyroidism type Ia and AHO.

Bone Neoplasms↗
PubMed2006

Familial pachydermoperiostosis in association with protein-losing enteropathy.

In this report we describe a rare association of pachydermoperiostosis with protein-losing enteropathy (PLE) in a family of three brothers. The first brother had the complete form of pachydermoperiostosis along with PLE. The second brother had the 'forme fruste' of pachydermoperiostosis, with minimal skin changes, bony abnormalities and PLE, which was due to intestinal lymphangiectasia. The third brother had an incomplete form of pachydermoperiostosis without evidence of PLE. To our knowledge, the association of pachydermoperiostosis with PLE due to intestinal lymphangiectasia has not been reported previously.

Adolescent↗
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↗