ORCID Profile
0000-0002-5331-4420
Current Organisations
University of South Australia
,
Alfred Health
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Publisher: American Society for Microbiology
Date: 02-2008
DOI: 10.1128/IAI.01138-07
Abstract: Despite the widely held belief that gastric acid serves as a barrier to bacterial pathogens, there are almost no experimental data to support this hypothesis. We have developed a mouse model to quantify the effectiveness of gastric acid in mediating resistance to infection with ingested bacteria. Mice that were constitutively hypochlorhydric due to a mutation in a gastric H + /K + -ATPase (proton pump) gene were infected with Yersinia enterocolitica, Salmonella enterica serovar Typhimurium, Citrobacter rodentium , or Clostridium perfringens cells or spores. Significantly greater numbers of Yersinia, Salmonella , and Citrobacter cells ( P ≤ 0.006) and Clostridium spores ( P = 0.02) survived in hypochlorhydric mice, resulting in reduced median infectious doses. Experiments involving intraperitoneal infection or infection of mice treated with antacids indicated that the increased sensitivity of hypochlorhydric mice to infection was entirely due to the absence of stomach acid. Apart from establishing the role of gastric acid in nonspecific immunity to ingested bacterial pathogens, our model provides an excellent system with which to investigate the effects of hypochlorhydria on susceptibility to infection and to evaluate the in vivo susceptibility to gastric acid of orally administered therapies, such as vaccines and probiotics.
Publisher: Springer Science and Business Media LLC
Date: 03-2009
DOI: 10.1038/NATURE07822
Publisher: American Society for Microbiology
Date: 10-2009
DOI: 10.1128/IAI.00548-09
Abstract: The essential toxin in Clostridium perfringens -mediated gas gangrene or clostridial myonecrosis is alpha-toxin, although other toxins and extracellular enzymes may also be involved. In many bacterial pathogens extracellular sialidases are important virulence factors, and it has been suggested that sialidases may play a role in gas gangrene. C. perfringens strains have combinations of three different sialidase genes, two of which, nanI and nanJ , encode secreted sialidases. The nanI and nanJ genes were insertionally inactivated by homologous recombination in derivatives of sequenced strain 13 and were shown to encode two functional secreted sialidases, NanI and NanJ. Analysis of these derivatives showed that NanI was the major sialidase in this organism. Mutation of nanI resulted in loss of most of the secreted sialidase activity, and the residual activity was eliminated by subsequent mutation of the nanJ gene. Only a slight reduction in the total sialidase activity was observed in a nanJ mutant. Cytotoxicity assays using the B16 melanoma cell line showed that supernatants containing NanI or overexpressing NanJ enhanced alpha-toxin-mediated cytotoxicity. Finally, the ability of nanI , nanJ , and nanIJ mutants to cause disease was assessed in a mouse myonecrosis model. No attenuation of virulence was observed for any of these strains, providing evidence that neither the NanI sialidase nor the NanJ sialidase is essential for virulence.
Publisher: Springer Science and Business Media LLC
Date: 12-2020
Publisher: Springer Science and Business Media LLC
Date: 20-03-2017
DOI: 10.1038/BMT.2017.37
Abstract: High-risk (HR) multiple myeloma (MM) has poor outcomes with conventional therapy. Tandem autologous-non-myeloablative (NMA) allogeneic stem cell transplantation (autologous stem cell transplantation (ASCT)-NMA allogeneic SCT) is potentially curative secondary to graft-versus-myeloma effect. We retrospectively analysed ASCT-NMA allogeneic SCT outcomes of 59 HR and relapsed MM patients. At a median follow-up of 35.8 months, the outcomes for HR-MM upfront tandem ASCT-NMA allogeneic SCT and standard-risk (SR) MM upfront ASCT alone were comparable (median PFS 1166 days versus 1465 days, P=0.36 median overall survival (OS) not reached in both cohorts, P=0.31). The 5-year PFS and OS of patients who had ASCT-NMA allogeneic SCT after relapsing from previous ASCT were 30% and 48% respectively. High CD3+ cell dose (>3 × 10
Publisher: Springer New York
Date: 2018
DOI: 10.1007/978-1-4939-7841-0_8
Abstract: This chapter describes a strategy for mapping linear B-cell epitopes of proteins using synthetic biotinylated peptides in an ELISA.A set of overlapping peptides were designed based upon a known amino acid sequence of the target protein, VapA (Virulence-associated Protein A) of the bacterium Rhodococcus equi, an important pulmonary pathogen in foals. The peptides synthesized as biotinylated peptides were coated directly onto micro titer plates which had been pre-coated with NeutrAvidin™ and used to screen sera from foals confirmed to have R. equi disease. A linear B-cell epitope was identified which corresponded to a 20 mer sequence of the VapA protein.
Publisher: Wiley
Date: 14-07-2015
DOI: 10.1111/TRF.13233
Abstract: Nivestim is a biosimilar approved for the same indications as Neupogen including the mobilization of autologous peripheral blood stem cells (PBSCs). The clinical efficacy and safety of Nivestim for this use have not been formally assessed in clinical trials. In our retrospective single-center study we compared variables of PBSC mobilization and engraftment of 60 patients mobilized with Nivestim to that of 38 patients mobilized with Neupogen. We found no difference between Nivestim and Neupogen in peripheral blood CD34+ at first leukapheresis (47 × 10(6) cells/L vs. 60 × 10(6) cells/L, p = 0.48) nor the total CD34+ collected (5.37 × 10(6)/kg vs. 4.59 × 10(6) /kg, p = 0.22). However, a difference in the median number of leukapheresis procedures (one vs. two, p = 0.0007) was observed. Eighty-one patients (51 Nivestim and 30 Neupogen mobilized) went on to transplantation. Median time to neutrophil engraftment (15 days vs. 13.5 days, p = 0.09) and platelet (PLT) engraftment (20 days vs. 18 days, p = 0.01) was longer in the Nivestim group. The significant delay in PLT engraftment did not, however, translate to increased PLT transfusions (two vs. three, p = 0.2) or impact significantly on hospitalization time for admissions within 30 days posttransplant (20 days vs. 18 days, p = .17). Nivestim is as effective as Neupogen for PBSC mobilization however, its use was associated with a delay in PLT recovery. A prospective study should be conducted to confirm our findings.
Publisher: Springer Science and Business Media LLC
Date: 21-10-2021
No related grants have been discovered for Tongted Das.