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Biomedical subjects

V Chaturvedi

Publications and source records attributed to V Chaturvedi.

At least 19 recordsLinked to original sources
PubMed2006

Interlaboratory study of quality control isolates for a broth microdilution method (modified CLSI M38-A) for testing susceptibilities of dermatophytes to antifungals.

The Clinical and Laboratory Standards Institute (CLSI; formerly National Committee for Clinical Laboratory Standards, or NCCLS) M38-A standard for the susceptibility testing of filamentous fungi does not specifically address the testing of dermatophytes. In 2003, a multicenter study investigated the reproducibility of the microdilution method developed at the Center for Medical Mycology, Cleveland, Ohio, for testing the susceptibility of dermatophytes. Data from that study supported the introduction of this method for testing dermatophytes in the future version of the CLSI M38-A standard. In order for the method to be accepted by CLSI, appropriate quality control isolates needed to be identified. To that end, an interlaboratory study, involving the original six laboratories plus two additional sites, was conducted to evaluate potential candidates for quality control isolates. These candidate strains included five Trichophyton rubrum strains known to have elevated MICs to terbinafine and five Trichophyton mentagrophytes strains. Antifungal agents tested included ciclopirox, fluconazole, griseofulvin, itraconazole, posaconazole, terbinafine, and voriconazole. Based on the data generated, two quality control isolates, one T. rubrum isolate and one T. mentagrophytes isolate, were identified and submitted to the American Type Culture Collection (ATCC) for inclusion as reference strains. Ranges encompassing 95.2 to 97.9% of all data points for all seven drugs were established.

Antifungal Agents↗
PubMed2006

Methods for establishing a surveillance system for cardiovascular diseases in Indian industrial populations.

OBJECTIVE: To establish a surveillance network for cardiovascular diseases (CVD) risk factors in industrial settings and estimate the risk factor burden using standardized tools. METHODS: We conducted a baseline cross-sectional survey (as part of a CVD surveillance programme) of industrial populations from 10 companies across India, situated in close proximity to medical colleges that served as study centres. The study subjects were employees (selected by age and sex stratified random sampling) and their family members. Information on behavioural, clinical and biochemical determinants was obtained through standardized methods (questionnaires, clinical measurements and biochemical analysis). Data collation and analyses were done at the national coordinating centre. FINDINGS: We report the prevalence of CVD risk factors among individuals aged 20-69 years (n = 19 973 for the questionnaire survey, n = 10 442 for biochemical investigations); mean age was 40 years. The overall prevalence of most risk factors was high, with 50.9% of men and 51.9% of women being overweight, central obesity was observed among 30.9% of men and 32.8% of women, and 40.2% of men and 14.9% of women reported current tobacco use. Self-reported prevalence of diabetes (5.3%) and hypertension (10.9%) was lower than when measured clinically and biochemically (10.1% and 27.7%, respectively). There was marked heterogeneity in the prevalence of risk factors among the study centres. CONCLUSION: There is a high burden of CVD risk factors among industrial populations across India. The surveillance system can be used as a model for replication in India as well as other developing countries.

Adult↗
PubMed2006

The proapoptotic tumor suppressor protein kinase C-delta is lost in human squamous cell carcinomas.

Protein kinase C (PKC)-delta is proapoptotic in human keratinocytes, and is downregulated or inactivated in keratinocytes expressing the activated Ha-ras oncogene, making it a candidate tumor suppressor gene for squamous cell carcinoma (SCC). We evaluated the significance of PKC-delta loss in transformed human keratinocytes using tumorigenic HaCaT Ras II-4 cells that have significantly reduced PKC-delta levels. Re-expression of PKC-delta by retrovirus transduction caused an increase in apoptosis and growth inhibition in culture. The growth inhibition induced by PKC-delta could be partially reversed by Bcl-x(L) expression, indicating that apoptosis was in part responsible for PKC-delta-induced growth inhibition. PKC-delta re-expression suppressed the tumorigenicity of HaCaT Ras II-4 cells in nude mice (P<0.05), and the small tumors that did form contained elevated levels of activated caspase-3, indicating increased apoptosis. In addition, we found that 29% (12/42) of human Bowen's disease (squamous carcinoma in situ) or SCC cases had absent or reduced PKC-delta when compared to the surrounding normal epidermis. These results indicate that PKC-delta inhibits transformed keratinocyte growth by inducing apoptosis, and that PKC-delta may function as a tumor suppressor in human SCCs where its loss in cells harboring activated ras could provide a growth advantage by conferring resistance to apoptosis.

Animals↗
PubMed2006

Correlation of MIC with outcome for Candida species tested against voriconazole: analysis and proposal for interpretive breakpoints.

Developing interpretive breakpoints for any given organism-drug combination requires integration of the MIC distribution, pharmacokinetic and pharmacodynamic parameters, and the relationship between the in vitro activity and outcome from both in vivo and clinical studies. Using data generated by standardized broth microdilution and disk diffusion test methods, the Antifungal Susceptibility Subcommittee of the Clinical and Laboratory Standards Institute has now proposed interpretive breakpoints for voriconazole and Candida species. The MIC distribution for voriconazole was determined using a collection of 8,702 clinical isolates. The overall MIC90 was 0.25 microg/ml and 99% of the isolates were inhibited at < or = 1 microg/ml of voriconazole. Similar results were obtained for 1,681 Candida isolates (16 species) from the phase III clinical trials. Analysis of the available data for 249 patients from six phase III voriconazole clinical trials demonstrated a statistically significant correlation (P = 0.021) between MIC and investigator end-of-treatment assessment of outcome. Consistent with parallel pharmacodynamic analyses, these data support the following MIC breakpoints for voriconazole and Candida species: susceptible (S), < or = 1 microg/ml; susceptible dose dependent (SDD), 2 microg/ml; and resistant (R), > or = 4 microg/ml. The corresponding disk test breakpoints are as follows: S, > or = 17 mm; SDD, 14 to 16 mm; and R, < or = 13 mm.

Antifungal Agents↗
PubMed2005

Synthesis and antitubercular activities of bis-glycosylated diamino alcohols.

Conjugate addition of diamines to glycosyl olefinic esters 1a and 1b followed by reduction of resulting bis-glycosyl beta-amino esters (2-7 and 14-19) with lithium aluminium hydride led to the respective glycosyl amino alcohols (8-13 and 20-25) in moderate to good yields. All the compounds were evaluated for antitubercular activity against Mycobacterium tuberculosis H(37)Ra and H(37)Rv. Few of the compounds exhibited antitubercular activity with MIC as low as 6.25-3.12microg/mL in virulent and avirulent strains. Compound 13 was found to be active against MDR strain and showed mild protection in mice.

Amino Alcohols↗
PubMed2005

Synthesis and antimycobacterial activities of glycosylated amino alcohols and amines.

Reduction of glycosyl beta-amino esters (6-14 and 25-30) with lithium aluminum hydride resulted in glycosyl amino alcohols (15-23 and 31-36) in good yields. However, reductive amination of glycosyl aldehydes (1-3) with different amines in presence of sodium borohydride resulted in good to moderate yields of glycosyl amines (37-41). All the compounds were evaluated for antitubercular activity against Mycobacterium tuberculosis H37Ra and H37Rv. Compounds 18, 21, 35 and 36 exhibited antitubercular activities with MIC ranging from 6.25 to 3.12 microg ml(-1).

Amines↗
PubMed2004

Synthesis of galactopyranosyl amino alcohols as a new class of antitubercular and antifungal agents.

The galactopyranosyl amino alcohols (3-16) were synthesised by regioselective oxirane ring opening of compound 2 with variety of amines and screened for antitubercular and antifungal activities. One of the compounds (16) showed potent activity against Mycobacterium tuberculosis H37 Rv in vitro and also displayed activity in MDR TB. The compound (16) was found to be superior to ethambutol clinically used anti TB drug in in vitro screen.

Amino Alcohols↗
PubMed2004

Resistance to UV-induced apoptosis in human keratinocytes during accelerated senescence is associated with functional inactivation of p53.

Compared to proliferating keratinocytes (KCs), growth-arrested KCs are relatively resistant to UV-light induced apoptosis. When KCs undergo confluency, or following exposure to anti-proliferative agents such as IFN-gamma plus a phorbol ester-12-O-tetradecanoylyphorbol-13-acetate (TPA), they convert from a proliferative to a nonproliferative state resembling senescence. Since p53 regulates UV-induced apoptosis of KCs, this report further characterizes p53 half-life, post-translational modifications, and transcriptional activity using cultured human KCs and living epidermal equivalents. The half-life of p53 in KCs was longer than fibroblasts (greater than approximately 3 h vs. 30 min). Exposure of proliferating KCs to UV-light induces post-translational modifications of p53 including acetylation of lysine-382 residues. By contrast, KCs undergoing irreversible growth arrest following confluency, or exposure to IFN-gamma plus TPA, were resistant to UV-induced apoptosis, and failed to undergo the acetylation modification of p53. Exposure of KCs to IFN-gamma plus TPA reduced total cellular p53 levels and reduced the transcriptional activity of p53. Addition of Trichostatin A (TSA), an inhibitor of de-acetylation, increased acetylation of lysine-382 in confluent KCs, thereby enhancing susceptibility of confluent cultures to UV-induced apoptosis. Pre-treatment of epidermal equivalents with IFN-gamma plus TPA also blocked UV-light induced increase in p53 levels, and reduced apoptosis. In conclusion, these studies demonstrate that growth arrested KCs may resist UV-light induced apoptosis by inactivating the pro-apoptotic function of p53.

Acetylation↗
PubMed2004

Intra- and interlaboratory study of a method for testing the antifungal susceptibilities of dermatophytes.

The National Committee for Clinical Laboratory Standards (NCCLS) M38-A standard for the susceptibility testing of conidium-forming filamentous fungi does not explicitly address the testing of dermatophytes. This multicenter study, involving six laboratories, investigated the MIC reproducibility of seven antifungal agents tested against 25 dermatophyte isolates (5 blinded pairs of five dermatophyte species per site for a total of 300 tests), using the method of dermatophyte testing developed at the Center for Medical Mycology, Cleveland, Ohio. The dermatophytes tested included Trichophyton rubrum, Trichophyton mentagrophytes, Trichophyton tonsurans, Epidermophyton floccosum, and Microsporum canis. Seven antifungals with activity against dermatophytes were tested, including ciclopirox, fluconazole, griseofulvin, itraconazole, posaconazole, terbinafine, and voriconazole. Interlaboratory MICs for all isolates were in 92 to 100% agreement at a visual endpoint reading of 50% inhibition as compared to the growth control and 88 to 99% agreement at a visual endpoint reading of 80% inhibition as compared to the growth control. Intralaboratory MICs between blinded pairs were in 97% agreement at a visual endpoint reading of 50% inhibition as compared to the growth control and 96% agreement at a visual endpoint reading of 80% inhibition as compared to the growth control. Data from this study support consideration of this method as an amendment to the NCCLS M38-A standard for the testing of dermatophytes.

Antifungal Agents↗
PubMed2004

Medical arthroscopy--emerging era of rheumatological intervention.

OBJECTIVE: To evaluate the safety and diagnostic value of arthroscopy performed by a rheumatologist. METHODS: Decisions for performing arthroscopy were taken when detailed clinical history-and relevant rheumatological investigations failed to arrive at a definite diagnosis. Arthroscopies were performed under local anesthesia as a daycare procedure. Synovial biopsies taken during procedures were subjected to histopathological examination (HPE). RESULTS: Of the 50 patients enrolled, 39 were males while 11 were females with mean age of 35.5 years. In lower limb oligoarthritis group of patients, three had macroscopic picture of crystal arthropathy, rest of the 29 patients revealed gross picture indicative of non-specific synovitis. While in polyarticular group of eight patients, three had macroscopic picture suggestive of crystal arthropathy (probably polyarticlar gout) while five were indicative of rheumatoid arthritis. In monoarticular disease pattern (n= 10) macroscopic picture findings were as follows- crystal arthropathy-two, tubercular-three, synovial chondromatosis-one and non-specific synovitis-two. HPE of synovium did not correlate in many cases. CONCLUSION: Arthroscopy using a 4 mm scope under local anesthesia in the hands of rheumatologists is a safe daycare procedure. In few cases arthroscopy helped in arriving at a final diagnosis but many patients remained undiagnosed. Both the rheumatologists and the pathologists require further experience in this field.

Adult↗
PubMed2003

Synthesis and antimycobacterial activity of 3,5-disubstituted thiadiazine thiones.

A series of 3,5-disubstituted thiadiazine thiones (4-24) have been synthesized by reaction of primary amines with carbon disulphide followed by cyclocondensation of the resulting intermediate with formaldehyde and primary amines or amino acids. The compounds were screened for antitubercular activity in vitro against Mycobacterium tuberculosis H37Rv. Three compounds 4, 12 and 18 showed antimycobacterial activity with MIC 12.5 microg/mL. Compound 4, was tested in vitro against five multidrug resistant (MDR) strains of M. tuberculosis and was found to be active. Compound 4 also exhibited activity in vivo. While all the mice died in the untreated group, the mean survival time (MST) of the compound treated mice was enhanced, 33% mice were surviving in treated group and the load of bacilli in the lung was considerably less in the compound treated group than in the untreated control group.

Animals↗
PubMed2002

Jagged-1 mediated activation of notch signaling induces complete maturation of human keratinocytes through NF-kappaB and PPARgamma.

Establishing an effective epidermal barrier requires a series of coordinated molecular events involving keratinocytes (KCs) within a stratified epithelium. Epidermal maturation depends on convergence of pathways involving components of NF-kappaB and peroxisome proliferator activated receptor (PPAR) signaling systems that promote terminal differentiation and production of a stratum corneum. The Notch-1 receptor and its ligand Delta-1 have been proposed by others to participate in early events in KC differentiation. Here, we establish differential expression patterns for several Notch receptors and ligands in normal human skin. These immunolocalization findings, together with functional studies demonstrating increased levels of Notch ligand/receptors occurring during the onset of differentiation, prompted use of a soluble Notch ligand, a peptide derived from the most conspicuously expressed ligand in skin, Jagged-1. Exposing submerged KC monolayers to this peptide (JAG-1) in co-presence of elevated calcium ion concentration, produced stratification with loricrin expression. Using a living human epidermal equivalent (EE) model system, when submerged cultures were raised to an air/liquid interface to generate a fully mature epidermis, activation of Notch signaling was detected. Addition of JAG-1 peptide to submerged EEs was sufficient to induce epidermal maturation. Moreover, a soluble decoy Notch inhibitor prevented such differentiation and corneogenesis in human EEs exposed to either an air/liquid interface or to the JAG-1 peptide. In KC monolayers, addition of JAG-1 peptide induced IKKalpha mediated NF-kappaB activation, as well as increased PPARgamma expression. Immunoprecipitation/Western blot analysis revealed a physical association between the p65 subunit of NF-kappaB and PPARgamma. These results indicate that activation of Notch signaling is necessary for maturation of human epidermis, and activation by a soluble Notch ligand is sufficient to trigger complete KC differentiation including cornification.

Adult↗
PubMed2002

Optimal testing conditions for determining MICs and minimum fungicidal concentrations of new and established antifungal agents for uncommon molds: NCCLS collaborative study.

This collaborative three-center study evaluated NCCLS M38-A document testing conditions and other testing conditions for the antifungal susceptibility testing of 35 isolates of Aspergillus nidulans, A. terreus, Bipolaris hawaiiensis, B. spicifera, Cladophialophora bantiana, Dactylaria constricta, Fusarium solani, Paecilomyces lilacinus, Scedosporium prolificans, Trichoderma longibrachiatum, and Wangiella dermatitidis for itraconazole, three new triazoles (voriconazole, posaconazole, and ravuconazole), and amphotericin B. MICs and minimum fungicidal concentrations (MFCs) were determined in each center by using four media (standard RPMI-1640 [RPMI], RPMI with 2% dextrose [RPMI-2%], antibiotic medium 3 [M3], and M3 with 2% dextrose [M3-2%]) and two criteria of MIC determination (complete growth inhibition [MICs-0] and prominent growth inhibition [MICs-2]) at 24, 48 and 72 h. MFCs were defined as the lowest drug concentrations that yielded <3 colonies (approximately 99 to 99.5% killing activity). The reproducibility (within three wells) was higher among MICs-0 (93 to 99%) with either RPMI or M3 media than among all MICs-2 (86 to 95%) for the five agents at 48 to 72 h. The agreement for MFCs was lower (86 to 94%). Based on interlaboratory agreement, the optimal testing conditions were RPMI broth, 48 to 72 h of incubation and 100% growth inhibition (MIC-0); MFCs can be obtained after MIC determination with the above optimal testing parameters. These results warrant consideration for inclusion in the future version of the NCCLS M38 document. However, the role of these in vitro values as predictors of clinical outcome remains to be established in clinical trials.

Amphotericin B↗
PubMed2001

Prevalence of vaginal colonization by drug-resistant Candida species in college-age women with previous exposure to over-the-counter azole antifungals.

We enrolled 382 college-age women in a cross-sectional survey to investigate the relationship between use of over-the-counter (OTC) azole-based antifungal drugs and vaginal colonization by drug-resistant Candida. This study showed no correlation (P=.506) between previous OTC exposure and colonization of drug-resistant Candida in vaginal flora. However, a small number of resistant Candida species isolates were obtained from women with a history of multiple exposures to OTC antifungals; given the widespread use of these products, this may be an emerging concern.

Adult↗
PubMed2001

Molecular cloning, phylogenetic analysis and three-dimensional modeling of Cu,Zn superoxide dismutase (CnSOD1) from three varieties of Cryptococcus neoformans.

Cryptococcus neoformans (Cn), causal agent of fungal meningoencephalitis, has three varieties with variable host predilection. To explore mechanisms for these pathogenic differences, we have characterized Cu,Zn SOD gene (CnSOD1). A Saccharomyces cerevisiae sod1Delta mutant was complemented with Cn var. grubii yeast expression library. The complementing clone had an ORF of 462 bp and the deduced 154 aa sequence showed 61% identity with S. cerevisiae SOD1 and 53-65% with other eukaryotic SOD1s. Cn var. grubii CnSOD1 cDNA was used to clone corresponding cDNAs from var. neoformans and var. gattii. ORFs from three varieties revealed 20-29% differences in deduced aa (s) with a significant 6% non-synonymous aa substitution between Cn var. grubii and Cn var. gattii. Cosmid library screening and PCR cloning were used to obtain genomic SOD1, which was split by five introns with identical placements and a typical 5' splice junction sequence, GTNNGY. These introns also showed a large nt variation among the three Cn varieties. Phylogenetic analyses revealed CnSOD1 to be in a group distinct from other eukaryotic SOD1s and with a significant divergence of the var. grubii from var. gattii. The CnSOD1 -deduced protein was modeled based on the crystal structure of S. cerevisiae SOD1, which showed an excellent fit. Most of the non-synonymous aa substitutions occurred on the outside of the molecule and these may contribute to differences in antigenicity among the three varieties. Notably, Cn var. neoformans and var. gattii Cu,Zn SOD had three substitutions of glycine (Gly26, Gly92 and Gly123 for Asn26, Ser92 and Ser123) that may contribute to the observed lower thermostability of this enzyme vis-a-vis Cn var. grubii. This is the first nucleotide and structural comparison of a protein-encoding gene from the three Cn varieties, which may provide a framework for future studies on the role of Cu,Zn SOD in Cn pathogenesis.

Amino Acid Sequence↗
PubMed2001

Candida dubliniensis at a cancer center.

Candida dubliniensis, a germ tube-positive yeast first described and identified as a cause of oral candidiasis in patients with acquired immunodeficiency syndrome in Europe in 1995, has an expanding clinical and geographic distribution that appears to be similar to that of the other germ tube-positive yeast, Candida albicans. This study determined the frequency, clinical spectrum, drug susceptibility profile, and suitable methods for identification of this emerging pathogen at a cancer center in 1998 and 1999. Twenty-two isolates were recovered from 16 patients with solid-organ or hematologic malignancies or acquired immunodeficiency syndrome. Two patients with cancer had invasive infection, and 14 were colonized with fungus or had superficial fungal infection. All isolates produced germ tubes and chlamydospores at 37 degrees C, did not grow at 45 degrees C, and gave negative reactions with d-xylose and alpha-methyl-d-glucoside in the API 20 C AUX and ID 32 C yeast identification systems. Phenotypic identification was confirmed by molecular beacon probe technology. All isolates were susceptible to the antifungal drugs amphotericin B, 5-fluorocytosine, fluconazole, itraconazole, and ketoconazole.

Adult↗
PubMed2001

Abnormal NF-kappaB signaling pathway with enhanced susceptibility to apoptosis in immortalized keratinocytes.

The transcriptional activation and proper regulation of NF-kappaB is known to be important to the apoptotic resistant phenotype of epidermal-derived keratinocytes. By comparing and contrasting the responses of normal foreskin-derived keratinocytes versus an immortalized skin-derived keratinocyte cell line (i.e. HaCaT cells), several molecular defects involving NF-kappaB signaling pathway were delineated in the immortalized keratinocytes. While exposure to IFN-gamma plus TPA produces growth arrest in both normal and immortalized keratinocytes, with rapid phosphorylation of MEKKI and recruitment of distinctive protein kinase C isoforms into the signalosome complex, subsequent molecular events necessary for NF-kappaB activation were abnormal in HaCaT cells. This disrupted NF-kappaB activation in HaCaT cells was accompanied by enhanced susceptibility to UV-light induced apoptosis, which was associated with elevated levels of E2F-1 and decreased TRAF1/TRAF2 levels. Additional defects in HaCaT cells included markedly diminished levels of IKKbeta (and lack of induction of kinase activity) in response to inflammatory stimuli, a failure of p21(WAF1/CIP1) to associate with CDK2, and a decreased association between p65 and p300. These studies suggest caution in using HaCaT cells as a substitute for normal keratinocytes to study apoptosis in the skin. Thus, it appears that while the immortalized cells can escape cell cycle checkpoints by elevated levels of E2F-1, an adverse biological consequence of such dysregulated cell cycle control is the inability to activate the anti-apoptotic NF-kappaB signaling pathway. Therefore, exploiting this apoptosis vulnerability in pre-malignant, or immortalized cells, prior to acquiring a death-defying phenotype characteristic of more advanced malignant cell types, provides the basis for an early interventional therapeutic strategy for cutaneous oncologists.

Apoptosis↗