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Biomedical subjects

A Manna

Publications and source records attributed to A Manna.

At least 19 recordsLinked to original sources
PubMed2004

Studies on the antibacterial potentiality of isoflavones.

The isoflavonoid compounds 'YS11-YS21' were screened for possible antimicrobial property against 12 known Gram-positive and Gram-negative sensitive bacteria. YS11 and YS16 failed to show antimicrobial activity and YS12, 13, 14, 15, 17, 18 and 20 had moderate antimicrobial action. Compounds YS19 and YS21 showed pronounced antimicrobial property. YS19 and YS21 were then tested in vitro against 214 strains of bacteria from one Gram-positive and six Gram-negative genera. The minimum inhibitory concentration (MIC) of YS19 and YS21 was determined by agar dilution method and ranged from 25 to 200 mg/l in most strains. At concentrations of 30 and 60 microg/mouse these compounds offered significant protection to mice challenged with 50 median lethal dose (MLD) of a virulent strain of Salmonella Typhimurium.

Animals↗
PubMed2004

Addition of teicoplanin or vancomycin for the treatment of documented bacteremia due to gram-positive cocci in neutropenic patients with hematological malignancies: microbiological, clinical and economic evaluation.

A prospective, randomized, double-blind trial was conducted on 124 febrile patients with hematological malignancies to compare teicoplanin with vancomycin as an addition to the initial empiric amikacin-ceftazidime regimen after documented bacteremia due to gram-positive cocci. At enrollment, patients in both groups were comparable with respect to age, sex, underlying hematologic disorders and duration of neutropenia. Rates of therapeutic success were 55/63 (87.3%) in the teicoplanin group and 56/61 (91.8%) in the vancomycin group (p = 0.560). The mean duration of treatment was similar, being 12.2 and 11.4 days, respectively (p = 0.216). Patients treated with teicoplanin remained febrile for slightly longer than those treated with vancomycin (4.9 vs. 4.0 days) (p = 0.013). Thirteen patients experienced an adverse drug reaction, but without any significant difference in the two arms. Isolated staphylococci showed a progressive and significant decrease in susceptibility to both glycopeptides during the 8 study years. The economic analysis performed showed that the addition of vancomycin is cost-saving.

Adult↗
PubMed2003

Statistical analysis of impact parameters of soft nose bullet fired on windowpane.

Proper collection of glass evidence from crime spot is very important for its latter probative values. Glass evidence when properly collected and analyzed becomes a powerful witness and it can speak truth long after the crime. In criminal investigation glass evidence can tell what had happened and when it had happened. In the present study, a statistical regression analysis relationship between thickness of windowpane used as targets by soft nose bullet using.315"/8mm caliber sporting gun made in ordnance factory, India and various associated impact parameters were investigated. The relationship is found to be reasonably linear. The ballistics performance of windowpane has been found to correlate with the shear strength behavior above the elastic limit.

Journal Article↗
PubMed2003

Growth-associated production and characterization of poly (3-hydroxybutyric acid) of Azotobacter beijerinckii DAR-102.

Production of poly (3-hydroxybutyric acid) [P(3HB)] by Azotobacter beijerinckii DAR-102 isolated in this laboratory has been optimized under batch-culture. The accumulatad polymer attained 58% of cell dry mass during mid-stationary phase with an yield of 0.58 g/l when grown in nitrogen-free medium. The optimum concentration of glucose and fructose for P(3HB) production was 3% (w/v) and 2% (w/v) respectively while that of casamino acid and tryptose was 0.1% (w/v). Phosphate at a concentration suboptimal for growth and limitation of oxygen in the medium favoured P(3HB) accumulation. The production of P(3HB) was maximum with an inoculum dose of 4% (v/v). The accumulated polymer was isolated by direct chloroform extraction of the dry cell mass and purified by precipitation with diethyl ether. The purified polymer has been characterized in terms of its solubility properties, melting temperature, and UV-, IR- and NMR-spectroscopic analyses.

Azotobacter↗
PubMed2001

Crystal structure of the SarR protein from Staphylococcus aureus.

The expression of virulence determinants in Staphylococcus aureus is controlled by global regulatory loci (e.g., sarA and agr). The sar (Staphylococcus accessory regulator) locus is composed of three overlapping transcripts (sarA P1, P3, and P2, transcripts initiated from the P1, P3, and P2 promoters, respectively), all encoding the 124-aa SarA protein. The level of SarA, the major regulatory protein, is partially controlled by the differential activation of the sarA promoters. We previously partially purified a 13.6-kDa protein, designated SarR, that binds to the sarA promoter region to down-modulate sarA transcription from the P1 promoter and subsequently SarA expression. SarR shares sequence similarity to SarA, and another SarA homolog, SarS. Here we report the 2.3 A-resolution x-ray crystal structure of the dimeric SarR-MBP (maltose binding protein) fusion protein. The structure reveals that the SarR protein not only has a classic helix-turn-helix module for DNA binding at the major grooves, but also has an additional loop region involved in DNA recognition at the minor grooves. This interaction mode could represent a new functional class of the "winged helix" family. The dimeric SarR structure could accommodate an unusually long stretch of approximately 27 nucleotides with two or four bending points along the course, which could lead to the bending of DNA by 90 degrees or more, similar to that seen in the catabolite activator protein (CAP)-DNA complex. The structure also demonstrates the molecular basis for the stable dimerization of the SarR monomers and possible motifs for interaction with other proteins.

Amino Acid Sequence↗
PubMed2001

Characterization of sarR, a modulator of sar expression in Staphylococcus aureus.

The expression of virulence determinants in Staphylococcus aureus is controlled by global regulatory loci (e.g., sar and agr). The sar locus is composed of three overlapping transcripts (sar P1, P3, and P2 transcripts from P1, P3, and P2 promoters, respectively), all encoding the 372-bp sarA gene. The level of SarA, the major regulatory protein, is partially controlled by the differential activation of sar promoters. We previously partially purified a approximately 12 kDa protein with a DNA-specific column containing a sar P2 promoter fragment. In this study, the putative gene, designated sarR, was identified and found to encode a 13.6-kDa protein with homology to SarA. Transcriptional and immunoblot studies revealed the sarR gene to be expressed in other staphylococcal strains. Recombinant SarR protein bound sar P1, P2, and P3 promoter fragments in gel shift and footprinting assays. A sarR mutant expressed a higher level of P1 transcript than the parent, as confirmed by promoter green fluorescent protein fusion assays. As the P1 transcript is the predominant sar transcript, we confirmed that the sarR mutant expressed more SarA than the parental strain. We thus proposed that SarR is a regulatory protein that binds to the sar promoters to down-regulate P1 transcription and the ensuing SarA protein expression.

Amino Acid Sequence↗
PubMed2000

Use of ethinyl estradiol to reverse the antiestrogenic effects of clomiphene citrate in patients undergoing intrauterine insemination: a comparative, randomized study.

OBJECTIVE: To compare the effectiveness of clomiphene citrate used alone and in combination with ethinyl E2 for the induction of ovulation in patients undergoing IUI. DESIGN: Randomized, double-blind study. SETTING: Four infertility treatment centers. PATIENT(S): Women aged 25-35 years with infertility of at least 2 years' duration and oligomenorrhea or amenorrhea associated with a positive menstrual response to an IM progesterone challenge. INTERVENTION(S): A total of 64 patients were randomized to treatment with CC (100 mg daily for 5 days) or CC (100 mg daily for 5 days) plus ethinyl E2 (0.05 mg daily for 5 days). MAIN OUTCOME MEASURE(S): The uterine artery pulsatility index, number of preovulatory follicles, endometrial thickness, and pregnancy rate. RESULT(S): Both treatment regimens increased FSH, LH, and 17beta-E2 levels, with no statistically significant differences. There was a statistically significant difference in endometrial thickness between the two treatment groups. No statistically significant differences were noted in pulsatility index values or in the number of preovulatory follicles. CONCLUSION(S): Ethinyl E2 can reverse the deleterious effects of CC on endometrial thickness, which may contribute to higher pregnancy rates.

Adult↗
PubMed2000

Degradation of microbial polyester poly(3-hydroxybutyrate) in environmental samples and in culture.

Poly(3-hydroxybutyrate) [P(3HB)] test-pieces prepared from the polymer produced by Azotobacter chroococcum were degraded in natural environments like soil, water, compost and sewage sludge incubated under laboratory conditions. Degradation in terms of % weight loss of the polymer was maximum (45%) in sewage sludge after 200 days of incubation at 30 degrees C. The P(3HB)-degrading bacterial cultures (36) isolated from degraded test-pieces showed different degrees of degradation in polymer overlayer method. The extent of P(3HB) degradation increases up to 12 days of incubation and was maximum at 30 degrees C for majority of the cultures. For most efficient cultures the optimum concentration of P(3HB) for degradation was 0.3% (w/v). Supplementation of soluble carbon sources like glucose, fructose and arabinose reduced the degradation while it was almost unaffected with lactose. Though the cultures degraded P(3HB) significantly, they were comparatively less efficient in utilizing copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate [P(3HB-co-3HV)].

Arabinose↗
PubMed2000

Acute leukemia following a previous malignancy: do acute lymphoid leukemia and acute myeloid leukemia have common risk factors?

INTRODUCTION: Within the framework of the GIMEMA Study Group, the characteristics of acute lymphoid leukemia and acute myeloid leukemia occurring in patients who have suffered a previous malignancy were studied. Assessment was also made of the clinical course, laboratory features and overall outcome of these conditions. MATERIALS AND METHODS: A four-year, multi-center retrospective study was conducted to evaluate the effect of treatment for previous hematological malignancy on the development of secondary leukemia. The study collected in the GIMEMA Archive of Adult Acute Leukemia 3934 new cases of acute leukemia (2964 AML, 901 ALL, 60 acute biphenotypic leukemia). Among these cases, data were evaluated from patients with a personal history of a previous malignancy, and included inquiring into demographic data, history of neoplastic diseases in the 1st degree relatives, type and treatment of the previous malignancy, latency until the development of a secondary acute leukemia diagnosis, laboratory features, treatment and outcome at the onset of secondary acute leukemia. RESULTS: Approximately 200 (5.1%) patients presented a previous malignancy. Twenty-one were affected by ALL and 179 by AML. The proportion of patients with secondary AML was higher than that of patients with secondary ALL (179/2964 vs 21/901, O.R. 2.69-95% C.I. 1.66-4.39, P<0.001). The median latency, from the onset of the previous malignancy to the development of secondary ALL was 27 months and to the development of secondary AML was 52 months (P<0.05). Furthermore, of patients who previously received chemotherapy more developed a second AML (66/127 sAML vs 5/21 sALL; O.R. 3.46-95% C.I. 1.10-11.56, P<0.01). CONCLUSION: In most cases, chemotherapy treatment for a previous malignancy can play a role in the development of secondary AML. In almost all cases of secondary ALL, the role of previous drugs does not appear to be relevant. On the basis of our analysis, performed systematically for the first time on a large adult series of acute leukemia, we conclude that in these patients a biological predisposition to cancer may be suspected.

Acute Disease↗
PubMed2000

Feasibility of peripheral blood stem cell rescue as intensification in elderly patients with acute myelocytic leukaemia: a pilot study from the Gimema Group. Gruppo Italiano Malattie Ematologiche Maligne Dell'Adulto.

Elderly patients with untreated acute myeloid leukaemia (AML, n = 47) tested the feasibility of out-patient consolidation therapy and post-consolidation treatment (for patients aged < 71 years) with autologous peripheral blood stem cell transplantation (APBSCT). Overall, 13 patients out of 24 (51%) who achieved complete remission (CR) were eligible for further treatment after consolidation. Five patients were primed with granulocyte colony stimulating factor (G-CSF); a suitable number of CD34+ cells were harvested in three patients and were actually autotransplanted. The toxicity of APBSCT was negligible. Psychosocial problems impaired treatment of some patients on an out-patient basis. Resistant disease, toxicity and logistic problems reduced the number of patients to whom this procedure could actually be applied.

Acute Disease↗
PubMed2000

Agr-independent regulation of fibronectin-binding protein(s) by the regulatory locus sar in Staphylococcus aureus.

Fibronectin-binding proteins (FnBPs) are thought to be important for the attachment of Staphylococcus aureus during infection. The regulation of the genes fnbA and fnbB by the global regulatory loci sar and agr was examined using site-specific regulatory mutants of S. aureus strain Newman. The results from binding assays using both aqueous and solid-phase fibronectin as well as ligand blotting with biotinylated fibronectin showed that the expression of FnBPA is enhanced in the agr mutant but inhibited in the sar mutant and the sar-agr double mutant. The same regulatory pattern was observed in Northern blot analysis using fnbA-specific probes. The introduction of sar on a multicopy plasmid increased the already enhanced fnbA transcription of the agr mutant. FnBPB was not detectable by ligand blotting and the fnbB promoter activity in promoter fusion assays was not affected by either sar or agr. The sequence encompassing ORF3 located upstream of sarA was found to be essential for the activation of fnbA transcription. We hypothesize that this sequence may modulate SarA expression and/or activity on the post-transcriptional level. Gel shift assays demonstrated that SarA binds to the fnbA promoter fragments, probably as a dimer. DNase I footprinting assays with SarA revealed a protected area of 102 bp upstream of fnbA.

Adhesins, Bacterial↗
PubMed2000

Synthesis and accumulation of poly(3-hydroxybutyric acid) by Rhizobium sp.

Forty-two Rhizobium strains obtained from different culture collections were evaluated quantitatively for poly(3-hydroxy-butyric acid) [PHB] production in shake flask culture. The majority of the strains produced the maximum amount of PHB during the late exponential or stationary phase of growth. Synthesis and accumulation of PHB in different species of Rhizobium were found to vary between 1-38% of their dry biomass. Growth and PHB production by the Rhizobium strain TAL-640 were greatly influenced by the C-source and D-mannitol was fundamental to both processes. The identity and purity of PHB isolated from TAL-640 have also been confirmed by UV-, IR- and 1H-NMR spectroscopic analyses.

Bradyrhizobium↗
PubMed1999

Synthesis of Silicalite-1 in Bicontinuous Microemulsion Containing AOT.

Silicalite-1 has been hydrothermally synthesized in a bicontinuous microemulsion of tetraethylenepentamine-sodium bis(2-ethylhexly) sulfosuccinate (AOT)-water system containing fluoride ions. The presence of AOT (an anionic surfactant) has been found to be essential for the formation of Silicalite-1 in bulk tetraethylene pentamine solvent. The tetrahedral binding sites of silicon atom have been confirmed by 29Si magic angle spinning NMR and FT-IR spectra. Thermogravimetric and differential thermal analysis studies on as-synthesized Silicalite-1 and X-ray diffraction pattern for calcined product established their structural stability. The scanning electron micrographs show the twinned and uniform morphology of crystals. The presence of additive (AOT) lengthens the nucleation period and helps to produce a large size crystal of Silicalite-1. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

Accumulation of poly (3-hydroxybutyric acid) by some soil Streptomyces.

In a limited-scale survey, 55 soil streptomycetes were screened for the accumulation of poly (3-hydroxybutyrate) [PHB]. Only 18% of the isolates accumulated PHB ranging between 1.9-7.8% of the dry biomass. The promising isolate DBCC-719, identified as Streptomyces griseorubiginosus, accumulated PHB amounting to 9.5% of the mycelial dry mass in the early stationary phase when grown in chemically defined medium with 2% (wt/vol) glucose as the sole source of carbon. Nitrogen-limiting conditions were inhibitory to growth and PHB accumulation. The isolated polymer was highly soluble in chloroform, gave a sharp peak at 235 nm on digestion with concentrated H(2)SO(4), and had a characteristic infrared spectrum.

3-Hydroxybutyric Acid↗
PubMed1999

Successful one antigen mismatched bone marrow transplant for chronic myeloid leukemia (CML) after two failed syngeneic transplants.

In May 1989, a 43-year-old woman with chronic myelocytic leukemia diagnosed in 1988 underwent a syngeneic bone marrow transplant (BMT), conditioned with cyclophosphamide-TBI while in chronic phase. Three years later, because of both cytogenetic and hematological relapse, she was treated with interferon-alpha (IFN-alpha) and hydroxyurea (HU) for 3 years. In 1994 while still in chronic phase, she was conditioned with busulfan-cyclophosphamide (BU-CY) and underwent a second syngeneic BMT. In 1996, following a further cytogenetic and hematological relapse, she was again placed on IFN-alpha and HU therapy for 13 months, when she was referred to our hospital in accelerated phase. In October 1997 following thiotepa, CY and anti-thymocyte globulin conditioning, she underwent an allogeneic BMT from her 1-Ag mismatched brother. She became Ph1 negative with full chimerism and normal hematological parameters; acute graft-versus-host disease (GVHD) grade 3 of the skin and chronic GVHD of the liver occurred. At 11 months follow-up she is in good clinical condition and with a Karnofsky score of 90%. The role of a graft-versus-leukemia (GVL) effect in securing and maintaining the complete remission is discussed.

Adult↗
PubMed1998

Effect of Co-Adsorbed Surfactant on the Structure of Self-Assembled Monolayer of Thiol on Polycrystalline Gold.

The structure and formation kinetics of a self-assembled monolayer (SAM) of long-chain alkane thiol in the presence and absence of an anionic surfactant like sodium dodecyl sulfate (SDS) has been studied using impedance, cyclic voltammetic, and quartz crystal microbalance (QCM) measurements. The comparison of these results, especially the ionic permeability of the monolayer, suggests a composite monolayer where both the surfactant and thiol molecules are cooperatively adsorbed to form distinct surfactant patches. This is further substantiated by the voltammetric experiments with redox probe in solution. A gradual change in the double layer capacitance value for the thiol monolayer alone (1.4 µF/cm2) to the composite monolayer (6.7 µF/cm2) and to the surfactant alone (11 µF/cm2) further supports the nature of the mixed monolayer. The kinetics of monolayer formation also shows interesting changes as revealed by the QCM studies, where a phase transition from simple to composite monolayer has been observed around an approximate coverage of 0.44. The same growth scheme is also observed for 1-pentanethiol, naphthalene disulfide, and diphenyl disulfide, suggesting that the mechanism appears to be general. Copyright 1998 Academic Press.

Journal Article↗
PubMed1997

Induction of Encystment and Poly-beta-Hydroxybutyric Acid Production by Azotobacter chroococcum MAL-201

Azotobacter chroococcum MAL-201, when grown under nitrogen-free conditions with excess glucose, accumulated poly-beta-hydroxybutyric acid amounting to 75% of cell dry weight at the late exponential phase. This led to induction of encystment, which increased steadily with concomitant intracellular degradation of the polymer. Increase in encystment and PHB production were parallel up to 0.5% (wt/vol) glucose. Further increase in glucose reduced cyst formation but enhanced PHB accumulation. Replacement of glucose by n-butyl alcohol and metabolically related compounds identified crotonate as the best encystment inducer followed by beta-hydroxybutyrate and butyrate, but PHB production was inhibited in general. Supplementation of medium with these compounds enhanced the onset of encystment, and only beta-hydroxybutyrate increased PHB accumulation significantly.

Journal Article↗