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Tensor modeling of MRSA bacteremia cytokine and transcriptional patterns reveals coordinated, outcome-associated immunological programs. PNAS NEXUS 2024; 3:pgae185. [PMID: 38779114 PMCID: PMC11109816 DOI: 10.1093/pnasnexus/pgae185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Accepted: 04/17/2024] [Indexed: 05/25/2024]
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) bacteremia is a common and life-threatening infection that imposes up to 30% mortality even when appropriate therapy is used. Despite in vitro efficacy determined by minimum inhibitory concentration breakpoints, antibiotics often fail to resolve these infections in vivo, resulting in persistent MRSA bacteremia. Recently, several genetic, epigenetic, and proteomic correlates of persistent outcomes have been identified. However, the extent to which single variables or their composite patterns operate as independent predictors of outcome or reflect shared underlying mechanisms of persistence is unknown. To explore this question, we employed a tensor-based integration of host transcriptional and cytokine datasets across a well-characterized cohort of patients with persistent or resolving MRSA bacteremia outcomes. This method yielded high correlative accuracy with outcomes and immunologic signatures united by transcriptomic and cytokine datasets. Results reveal that patients with persistent MRSA bacteremia (PB) exhibit signals of granulocyte dysfunction, suppressed antigen presentation, and deviated lymphocyte polarization. In contrast, patients with resolving bacteremia (RB) heterogeneously exhibit correlates of robust antigen-presenting cell trafficking and enhanced neutrophil maturation corresponding to appropriate T lymphocyte polarization and B lymphocyte response. These results suggest that transcriptional and cytokine correlates of PB vs. RB outcomes are complex and may not be disclosed by conventional modeling. In this respect, a tensor-based integration approach may help to reveal consensus molecular and cellular mechanisms and their biological interpretation.
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Viral afterlife: SARS-CoV-2 as a reservoir of immunomimetic peptides that reassemble into proinflammatory supramolecular complexes. Proc Natl Acad Sci U S A 2024; 121:e2300644120. [PMID: 38306481 PMCID: PMC10861912 DOI: 10.1073/pnas.2300644120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Accepted: 10/28/2023] [Indexed: 02/04/2024] Open
Abstract
It is unclear how severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection leads to the strong but ineffective inflammatory response that characterizes severe Coronavirus disease 2019 (COVID-19), with amplified immune activation in diverse cell types, including cells without angiotensin-converting enzyme 2 receptors necessary for infection. Proteolytic degradation of SARS-CoV-2 virions is a milestone in host viral clearance, but the impact of remnant viral peptide fragments from high viral loads is not known. Here, we examine the inflammatory capacity of fragmented viral components from the perspective of supramolecular self-organization in the infected host environment. Interestingly, a machine learning analysis to SARS-CoV-2 proteome reveals sequence motifs that mimic host antimicrobial peptides (xenoAMPs), especially highly cationic human cathelicidin LL-37 capable of augmenting inflammation. Such xenoAMPs are strongly enriched in SARS-CoV-2 relative to low-pathogenicity coronaviruses. Moreover, xenoAMPs from SARS-CoV-2 but not low-pathogenicity homologs assemble double-stranded RNA (dsRNA) into nanocrystalline complexes with lattice constants commensurate with the steric size of Toll-like receptor (TLR)-3 and therefore capable of multivalent binding. Such complexes amplify cytokine secretion in diverse uninfected cell types in culture (epithelial cells, endothelial cells, keratinocytes, monocytes, and macrophages), similar to cathelicidin's role in rheumatoid arthritis and lupus. The induced transcriptome matches well with the global gene expression pattern in COVID-19, despite using <0.3% of the viral proteome. Delivery of these complexes to uninfected mice boosts plasma interleukin-6 and CXCL1 levels as observed in COVID-19 patients.
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Diflunisal and Analogue Pharmacophores Mediating Suppression of Virulence Phenotypes in Staphylococcus aureus. Antibiotics (Basel) 2023; 12:1180. [PMID: 37508276 PMCID: PMC10376238 DOI: 10.3390/antibiotics12071180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Revised: 06/26/2023] [Accepted: 07/08/2023] [Indexed: 07/30/2023] Open
Abstract
Invasive methicillin-resistant Staphylococcus aureus (MRSA) infections are leading causes of morbidity and mortality that are complicated by increasing resistance to conventional antibiotics. Thus, minimizing virulence and enhancing antibiotic efficacy against MRSA is a public health imperative. We originally demonstrated that diflunisal (DIF; [2-hydroxy-5-(2,4-difluorophenyl) benzoic acid]) inhibits S. aureus virulence factor expression. To investigate pharmacophores that are active in this function, we evaluated a library of structural analogues for their efficacy to modulate virulence phenotypes in a panel of clinically relevant S. aureus isolates in vitro. Overall, the positions of the phenyl, hydroxyl, and carboxylic moieties and the presence or type of halogen (F vs. Cl) influenced the efficacy of compounds in suppressing hemolysis, proteolysis, and biofilm virulence phenotypes. Analogues lacking halogens inhibited proteolysis to an extent similar to DIF but were ineffective at reducing hemolysis or biofilm production. In contrast, most analogues lacking the hydroxyl or carboxylic acid groups did not suppress proteolysis but did mitigate hemolysis and biofilm production to an extent similar to DIF. Interestingly, chirality and the substitution of fluorine with chlorine resulted in a differential reduction in virulence phenotypes. Together, this pattern of data suggests virulence-suppressing pharmacophores of DIF and structural analogues integrate halogen, hydroxyl, and carboxylic acid moiety stereochemistry. The anti-virulence effects of DIF were achieved using concentrations that are safe in humans, do not impair platelet antimicrobial functions, do not affect S. aureus growth, and do not alter the efficacy of conventional antibiotics. These results offer proof of concept for using novel anti-virulence strategies as adjuvants to antibiotic therapy to address the challenge of MRSA infection.
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Diflunisal Attenuates Virulence Factor Gene Regulation and Phenotypes in Staphylococcus aureus. Antibiotics (Basel) 2023; 12:902. [PMID: 37237805 PMCID: PMC10215304 DOI: 10.3390/antibiotics12050902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 05/04/2023] [Accepted: 05/10/2023] [Indexed: 05/28/2023] Open
Abstract
Virulence factor expression is integral to pathogenicity of Staphylococcus aureus. We previously demonstrated that aspirin, through its major metabolite, salicylic acid (SAL), modulates S. aureus virulence phenotypes in vitro and in vivo. We compared salicylate metabolites and a structural analogue for their ability to modulate S. aureus virulence factor expression and phenotypes: (i) acetylsalicylic acid (ASA, aspirin); (ii) ASA metabolites, salicylic acid (SAL), gentisic acid (GTA) and salicyluric acid (SUA); or (iii) diflunisal (DIF), a SAL structural analogue. None of these compounds altered the growth rate of any strain tested. ASA and its metabolites SAL, GTA and SUA moderately impaired hemolysis and proteolysis phenotypes in multiple S. aureus strain backgrounds and their respective deletion mutants. Only DIF significantly inhibited these virulence phenotypes in all strains. The kinetic profiles of ASA, SAL or DIF on expression of hla (alpha hemolysin), sspA (V8 protease) and their regulators (sigB, sarA, agr (RNAIII)) were assessed in two prototypic strain backgrounds: SH1000 (methicillin-sensitive S. aureus; MSSA) and LAC-USA300 (methicillin-resistant S. aureus; MRSA). DIF induced sigB expression which is coincident with the significant inhibition of RNAIII expression in both strains and precedes significant reductions in hla and sspA expression. The inhibited expression of these genes within 2 h resulted in the durable suppression of hemolysis and proteolysis phenotypes. These results indicate that DIF modulates the expression of key virulence factors in S. aureus via a coordinated impact on their relevant regulons and target effector genes. This strategy may hold opportunities to develop novel antivirulence strategies to address the ongoing challenge of antibiotic-resistant S. aureus.
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Tensor-based insights into systems immunity and infectious disease. Trends Immunol 2023; 44:329-332. [PMID: 36997459 PMCID: PMC10411872 DOI: 10.1016/j.it.2023.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 03/06/2023] [Accepted: 03/07/2023] [Indexed: 03/31/2023]
Abstract
Profiling immune responses across several dimensions, including time, patients, molecular features, and tissue sites, can deepen our understanding of immunity as an integrated system. These studies require new analytical approaches to realize their full potential. We highlight recent applications of tensor methods and discuss several future opportunities.
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Impacts of NaHCO3 on β-Lactam Binding to PBP2a Protein Variants Associated with the NaHCO3-Responsive versus NaHCO3-Non-Responsive Phenotypes. Antibiotics (Basel) 2022; 11:antibiotics11040462. [PMID: 35453214 PMCID: PMC9028190 DOI: 10.3390/antibiotics11040462] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/23/2022] [Accepted: 03/26/2022] [Indexed: 12/13/2022] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) regulates resistance to β-lactams via preferential production of an alternative penicillin-binding protein (PBP), PBP2a. PBP2a binds many β-lactam antibiotics with less affinity than PBPs which are predominant in methicillin-susceptible (MSSA) strains. A novel, rather frequent in vitro phenotype was recently identified among clinical MRSA bloodstream isolates, termed “NaHCO3-responsiveness”. This phenotype features β-lactam susceptibility of certain MRSA strains only in the presence of NaHCO3. Two distinct PBP2a variants, 246G and 246E, have been linked to the NaHCO3-responsive and NaHCO3-non-responsive MRSA phenotypes, respectively. To determine the mechanistic impact of PBP2a variants on β-lactam susceptibility, binding profiles of a fluorescent penicillin probe (Bocillin-FL) to each purified PBP2a variant were assessed and compared to whole-cell binding profiles characterized by flow cytometry in the presence vs. absence of NaHCO3. These investigations revealed that NaHCO3 differentially influenced the binding of the fluorescent penicillin, Bocillin-FL, to the PBP2a variants, with binding intensity and rate of binding significantly enhanced in the 246G compared to the 246E variant. Of note, the NaHCO3-β-lactam (oxacillin)-responsive JE2 strain, which natively harbors the 246G variant, had enhanced Bocillin-FL whole-cell binding following exposure to NaHCO3. This NaHCO3-mediated increase in whole-cell Bocillin-FL binding was not observed in the NaHCO3-non-responsive parental strain, COL, which contains the 246E PBP2a variant. Surprisingly, genetic swaps of the mecA coding sites between JE2 and COL did not alter the NaHCO3-enhanced binding seen in JE2 vs. COL. These data suggest that the non-coding regions of mecA may be involved in NaHCO3-responsiveness. This investigation also provides strong evidence that the NaHCO3-responsive phenotype in MRSA may involve NaHCO3-mediated increases in both initial cell surface β-lactam binding, as well as ultimate PBP2a binding of β-lactams.
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Staphylococcus aureus adaptive evolution: Recent insights on how immune evasion, immunometabolic subversion and host genetics impact vaccine development. Front Cell Infect Microbiol 2022; 12:1060810. [PMID: 36636720 PMCID: PMC9831658 DOI: 10.3389/fcimb.2022.1060810] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 11/16/2022] [Indexed: 12/28/2022] Open
Abstract
Despite meritorious attempts, a S. aureus vaccine that prevents infection or mitigates severity has not yet achieved efficacy endpoints in prospective, randomized clinical trials. This experience underscores the complexity of host-S. aureus interactions, which appear to be greater than many other bacterial pathogens against which successful vaccines have been developed. It is increasingly evident that S. aureus employs strategic countermeasures to evade or exploit human immune responses. From entering host cells to persist in stealthy intracellular reservoirs, to sensing the environmental milieu and leveraging bacterial or host metabolic products to reprogram host immune responses, S. aureus poses considerable challenges for the development of effective vaccines. The fact that this pathogen causes distinct types of infections and can undergo transient genetic, transcriptional or metabolic adaptations in vivo that do not occur in vitro compounds challenges in vaccine development. Notably, the metabolic versatility of both bacterial and host immune cells as they compete for available substrates within specific tissues inevitably impacts the variable repertoire of gene products that may or may not be vaccine antigens. In this respect, S. aureus has chameleon phenotypes that have alluded vaccine strategies thus far. Nonetheless, a number of recent studies have also revealed important new insights into pathogenesis vulnerabilities of S. aureus. A more detailed understanding of host protective immune defenses versus S. aureus adaptive immune evasion mechanisms may offer breakthroughs in the development of effective vaccines, but at present this goal remains a very high bar. Coupled with the recent advances in human genetics and epigenetics, newer vaccine technologies may enable such a goal. If so, future vaccines that protect against or mitigate the severity of S. aureus infections are likely to emerge at the intersection of precision and personalized medicine. For now, the development of S. aureus vaccines or alternative therapies that reduce mortality and morbidity must continue to be pursued.
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Mechanistic Fingerprinting Reveals Kinetic Signatures of Resistance to Daptomycin and Host Defense Peptides in Streptococcus mitis-oralis. Antibiotics (Basel) 2021; 10:antibiotics10040404. [PMID: 33918000 PMCID: PMC8068394 DOI: 10.3390/antibiotics10040404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/01/2021] [Accepted: 04/06/2021] [Indexed: 11/16/2022] Open
Abstract
Streptococcus mitis-oralis (S. mitis-oralis) infections are increasingly prevalent in specific populations, including neutropenic cancer and endocarditis patients. S. mitis-oralis strains have a propensity to evolve rapid, high-level and durable resistance to daptomycin (DAP-R) in vitro and in vivo, although the mechanism(s) involved remain incompletely defined. We examined mechanisms of DAP-R versus cross-resistance to cationic host defense peptides (HDPs), using an isogenic S. mitis-oralis strain-pair: (i) DAP-susceptible (DAP-S) parental 351-WT (DAP MIC = 0.5 µg/mL), and its (ii) DAP-R variant 351-D10 (DAP MIC > 256 µg/mL). DAP binding was quantified by flow cytometry, in-parallel with temporal (1–4 h) killing by either DAP or comparative prototypic cationic HDPs (hNP-1; LL-37). Multicolor flow cytometry was used to determine kinetic cell responses associated with resistance or susceptibility to these molecules. While overall DAP binding was similar between strains, a significant subpopulation of 351-D10 cells hyper-accumulated DAP (>2–4-fold vs. 351-WT). Further, both DAP and hNP-1 induced cell membrane (CM) hyper-polarization in 351-WT, corresponding to significantly greater temporal DAP-killing (vs. 351-D10). No strain-specific differences in CM permeabilization, lipid turnover or regulated cell death were observed post-exposure to DAP, hNP-1 or LL-37. Thus, the adaptive energetics of the CM appear coupled to the outcomes of interactions of S. mitis-oralis with DAP and selected HDPs. In contrast, altered CM permeabilization, proposed as a major mechanism of action of both DAP and HDPs, did not differentiate DAP-S vs. DAP-R phenotypes in this S. mitis-oralis strain-pair.
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PACAP is a pathogen-inducible resident antimicrobial neuropeptide affording rapid and contextual molecular host defense of the brain. Proc Natl Acad Sci U S A 2021; 118:e1917623117. [PMID: 33372152 PMCID: PMC7817161 DOI: 10.1073/pnas.1917623117] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Defense of the central nervous system (CNS) against infection must be accomplished without generation of potentially injurious immune cell-mediated or off-target inflammation which could impair key functions. As the CNS is an immune-privileged compartment, inducible innate defense mechanisms endogenous to the CNS likely play an essential role in this regard. Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide known to regulate neurodevelopment, emotion, and certain stress responses. While PACAP is known to interact with the immune system, its significance in direct defense of brain or other tissues is not established. Here, we show that our machine-learning classifier can screen for immune activity in neuropeptides, and correctly identified PACAP as an antimicrobial neuropeptide in agreement with previous experimental work. Furthermore, synchrotron X-ray scattering, antimicrobial assays, and mechanistic fingerprinting provided precise insights into how PACAP exerts antimicrobial activities vs. pathogens via multiple and synergistic mechanisms, including dysregulation of membrane integrity and energetics and activation of cell death pathways. Importantly, resident PACAP is selectively induced up to 50-fold in the brain in mouse models of Staphylococcus aureus or Candida albicans infection in vivo, without inducing immune cell infiltration. We show differential PACAP induction even in various tissues outside the CNS, and how these observed patterns of induction are consistent with the antimicrobial efficacy of PACAP measured in conditions simulating specific physiologic contexts of those tissues. Phylogenetic analysis of PACAP revealed close conservation of predicted antimicrobial properties spanning primitive invertebrates to modern mammals. Together, these findings substantiate our hypothesis that PACAP is an ancient neuro-endocrine-immune effector that defends the CNS against infection while minimizing potentially injurious neuroinflammation.
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Perceptions and psychosocial judgement of patients with acne vulgaris. THE MEDICAL JOURNAL OF MALAYSIA 2020; 75:18-23. [PMID: 32008014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
INTRODUCTION People often judge others and make decisions based on the physical appearance of an individual. This study assesses the perception and psychosocial judgment on patients with acne vulgaris compared to those with clear skin. METHODS This survey was conducted in Penang from October 2016 to June 2017. Respondents were those who were ≥18 years. The survey was conducted using a questionnaire which consists of three randomly selected facial pictures, with at least one acne skin and one clear skin picture. RESULTS A total of 435 respondents were recruited. Two third of the respondents (76%) suffered or had suffered from acne. The skin was the first thing noticed by 76.1% respondents when viewing pictures with acne compared with 24.8% with clear skin (p <0.05). People with acne were perceived as being unattractive, sad, lonely, distant, unhealthy, disheveled and shy as compared to people with clear skin (p<0.05). People with clear skin were perceived to be healthier, confident, happy, attractive, successful and intelligent (p<0.05). Respondents were more willing to engage socially with people with clear skin rather than those with acne skin. A significantly higher proportion of respondents were likely to hire or vote for those with clear skin as compared to acne skin. People with acne were also perceived to have a lower educational level and poorer leadership quality. CONCLUSION The results of this survey showed that there were significantly negative perception and psychological judgement toward individuals with acne vulgaris. These negative impacts may affect social life of the acne sufferers, their prospect of employment and career opportunities.
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Lack of Activated Protein C Resistance in Healthy Hong Kong Chinese Blood Donors - Correlation with Absence of Arg506-Gln Mutation of Factor V Gene. Thromb Haemost 2018. [DOI: 10.1055/s-0038-1665404] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Abstract
SummaryVenous thromboembolism is rare in Chinese. To determine the incidence and disease profile of thrombophilia in Chinese patients with thrombosis, 52 unselected Chinese patients with documented venous thrombosis were studied for the presence of thrombophilia. Levels of antithrombin III (AT III), protein C (PC) and protein S (PS) as well as the presence of acquired lupus anticoagulant (LA) and anticardiolipin antibody (ACA) were investigated. Thirty patients were found to be abnormal. These consisted of 5 AT III deficiencies, 9 PC deficiencies, 10 PS deficiencies, 1 combined PC & PS deficiency (all in the heterozygous range), and 5 patients with LA and/or ACA. When the patients with LA and/or ACA are excluded, the incidence of hereditary thrombophilia is 25/47 i.e. 53.2%' which is much higher than those reported in studies of Caucasian patients selected under strict criteria. Family studies performed in 16 cases ot hereditary thrombophilia revealed involvement in 11 cases (68.7%); a total of 36 heterozygous family members were affected, most of which remain asymptomatic. Although 35 events predisposing to thrombosis (27 pregnancies, 1 oral contraceptive consumption and 7 surgical operations) were identified among these index patients, and the heterozygous family members, thrombosis was observed on only 6 occasions (17.1%). The data suggest that pregnancy and surgery do not carry the same degree of thrombotic risk in Chinese as in the Caucasian population with heterozygous AT III, PC and PS deficiency.
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1062 Hypnotic Use in Insomnia Clinic Following Direct-to-patient Education Tool. Sleep 2018. [DOI: 10.1093/sleep/zsy061.1061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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A 10-years retrospective study on Severe Cutaneous Adverse Reactions (SCARs) in a tertiary hospital in Penang, Malaysia. THE MEDICAL JOURNAL OF MALAYSIA 2018; 73:73-77. [PMID: 29703869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
INTRODUCTION Severe cutaneous adverse drug reactions (SCARs) are not uncommon and potentially lifethreatening. Our objective is to study the patient characteristics, the pattern of implicated drugs and treatment outcome among patients with SCARs. METHODS A 10-year retrospective analysis of SCARs cases in Penang General Hospital was carried out from January 2006 to December 2015. Data collection is based on the Malaysian Adverse Drug Reactions Advisory Committee registry and dermatology clinic records. RESULTS A total of 189 cases of SCARs were encountered (F:M ratio; 1.2:1.0; mean age of 45 year). The commonest manifestation was Stevens-Johnson Syndrome [SJS] (55.0%), followed by toxic epidermal necrolysis [TEN] (23.8%), drug rash with eosinophilia and systemic symptoms [DRESS] (12.7%), acute generalised exanthematous pustulosis [AGEP] (4.8%), SJS/TEN overlap syndrome (2.6%) and generalised bullous fixed drug eruptions [GBFDE] (1.1%). Mean time to onset for TEN/SJS/Overlap syndrome was 10.5±13 days; AGEP, three days; GBFDE, 2.5±0.7 days, and DRESS, 29.4±5.7 days. The most common drugs implicated were antibiotics (33.3%), followed by allopurinol (18.9%) and anticonvulsant (18.4%). Out of 154 cases of SJS/TEN/overlap syndrome, allopurinol was the commonest causative agents (20.1%). In DRESS, allopurinol accounts for 45.8% of the cases. The mortality rate in SJS, TEN and DRESS were 1.9%, 13.3% and 12.5% respectively. No mortality was observed in AGEP and GBFDE. CONCLUSION The commonest manifestations of SCARs in our setting were SJS, TEN and DRESS. Allopurinol was the most common culprit. Thus, judicious allopurinol use is advocated and pre-emptive genetic screening for HLAB *5801 should be considered.
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Whole-Genome Sequencing of Methicillin-Resistant Staphylococcus aureus Resistant to Fifth-Generation Cephalosporins Reveals Potential Non-mecA Mechanisms of Resistance. PLoS One 2016; 11:e0149541. [PMID: 26890675 PMCID: PMC4758708 DOI: 10.1371/journal.pone.0149541] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 02/02/2016] [Indexed: 01/28/2023] Open
Abstract
Fifth-generation cephalosporins, ceftobiprole and ceftaroline, are promising drugs for treatment of bacterial infections from methicillin-resistant Staphylococcus aureus (MRSA). These antibiotics are able to bind native PBP2a, the penicillin-binding protein encoded by the mecA resistance determinant that mediates broad class resistance to nearly all other beta-lactam antibiotics, at clinically achievable concentrations. Mechanisms of resistance to ceftaroline based on mecA mutations have been previously described. Here we compare the genomes of 11 total parent-daughter strains of Staphylococcus aureus for which specific selection by serial passaging with ceftaroline or ceftobiprole was used to identify novel non-mecA mechanisms of resistance. All 5 ceftaroline-resistant strains, derived from 5 different parental strains, contained mutations directly upstream of the pbp4 gene (coding for the PBP4 protein), including four with the same thymidine insertion located 377 nucleotides upstream of the promoter site. In 4 of 5 independent ceftaroline-driven selections, we also isolated mutations to the same residue (Asn138) in PBP4. In addition, mutations in additional candidate genes such as ClpX endopeptidase, PP2C protein phosphatase and transcription terminator Rho, previously undescribed in the context of resistance to ceftaroline or ceftobiprole, were detected in multiple selections. These genomic findings suggest that non-mecA mechanisms, while yet to be encountered in the clinical setting, may also be important in mediating resistance to 5th-generation cephalosporins.
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Nonredundant Roles of Interleukin-17A (IL-17A) and IL-22 in Murine Host Defense against Cutaneous and Hematogenous Infection Due to Methicillin-Resistant Staphylococcus aureus. Infect Immun 2015; 83:4427-37. [PMID: 26351278 PMCID: PMC4598415 DOI: 10.1128/iai.01061-15] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 08/28/2015] [Indexed: 12/12/2022] Open
Abstract
Staphylococcus aureus is the leading cause of skin and skin structure infections (SSSI) in humans. Moreover, the high frequency of recurring SSSI due to S. aureus, particularly methicillin-resistant S. aureus (MRSA) strains, suggests that infection induces suboptimal anamnestic defenses. The present study addresses the hypothesis that interleukin-17A (IL-17A) and IL-22 play distinct roles in immunity to cutaneous and invasive MRSA infection in a mouse model of SSSI. Mice were treated with specific neutralizing antibodies against IL-17A and/or IL-22 and infected with MRSA, after which the severity of infection and host immune response were determined. Neutralization of either IL-17A or IL-22 reduced T cell and neutrophil infiltration and host defense peptide elaboration in lesions. These events corresponded with increased abscess severity, MRSA viability, and CFU density in skin. Interestingly, combined inhibition of IL-17A and IL-22 did not worsen abscesses but did increase gamma interferon (IFN-γ) expression at these sites. The inhibition of IL-22 led to a reduction in IL-17A expression, but not vice versa. These results suggest that the expression of IL-17A is at least partially dependent on IL-22 in this model. Inhibition of IL-17A but not IL-22 led to hematogenous dissemination to kidneys, which correlated with decreased T cell infiltration in renal tissue. Collectively, these findings indicate that IL-17A and IL-22 have complementary but nonredundant roles in host defense against cutaneous versus hematogenous infection. These insights may support targeted immune enhancement or other novel approaches to address the challenge of MRSA infection.
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Ceftobiprole- and ceftaroline-resistant methicillin-resistant Staphylococcus aureus. Antimicrob Agents Chemother 2015; 59:2960-3. [PMID: 25753637 PMCID: PMC4394828 DOI: 10.1128/aac.05004-14] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 03/02/2015] [Indexed: 02/07/2023] Open
Abstract
The role of mecA mutations in conferring resistance to ceftobiprole and ceftaroline, cephalosporins with anti-methicillin-resistant Staphylococcus aureus (MRSA) activity, was determined with MRSA strains COL and SF8300. The SF8300 ceftaroline-passaged mutant carried a single mecA mutation, E447K (E-to-K change at position 447), and expressed low-level resistance. This mutation in COL conferred high-level resistance to ceftobiprole but only low-level resistance to ceftaroline. The COL ceftaroline-passaged mutant, which expressed high-level resistance to ceftobiprole and ceftaroline, had mutations in pbp2, pbp4, and gdpP but not mecA.
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Malaysian Clinical Practice Guideline for the Management of Psoriasis Vulgaris: Summary of recommendations for management in primary healthcare setting. MALAYSIAN FAMILY PHYSICIAN : THE OFFICIAL JOURNAL OF THE ACADEMY OF FAMILY PHYSICIANS OF MALAYSIA 2014; 9:16-21. [PMID: 25606292 PMCID: PMC4265965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
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Cutaneous side-effects of epidermal growth factor receptor-tyrosine kinase inhibitor (TKI) in the treatment of lung cancer: description and its management. THE MEDICAL JOURNAL OF MALAYSIA 2012; 67:222-223. [PMID: 22822651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Epidermal growth factor receptor (EGFR)--tyrosine kinase inhibitors (TKI) like erlotinib and gefitinib have been approved as monotherapy for the treatment of patients with locally advanced or metastatic non small cell lung cancer (NSCLC) after failure of at least one prior chemotherapy regimen. The use of EGFR-TKI is associated with unique and dramatic dermatologic side effects. We report 2 patients with NSCLC developing a typical acneiform (papulo-pustular) eruption shortly after initiation of EGFR-TKI.
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Kaposi's sarcoma: case report and treatment options. THE MEDICAL JOURNAL OF MALAYSIA 2011; 66:383-384. [PMID: 22299569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Kaposi's sarcoma (KS) is strongly associated with Human Herpes Virus 8 (HHV8) and Human Immunodeficiency Virus infection (HIV). It was the first malignancy to be linked with Acquired Immunodeficiency Syndrome (AIDS). We report a case of Kaposi's sarcoma in a newly diagnosed retroviral homosexual patient with CD4 count of 21. He had multiple firm discrete violaceous plaques and nodules scattered over the face, scalp, hard palate, trunk and genitalia. Biopsy of a skin nodule over the trunk and a biopsy of a lesion from the gastric mucosa confirmed Kaposi's sarcoma. He was started on Highly Active Antiretroviral Therapy (HAART) and cryotherapy (liquid nitrogen) was given for the lesions over the skin. He responded well to treatment. Liquid nitrogen is a useful adjuvant treatment for Kaposi's sarcoma.
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Structured modeling of recombinant protein production in batch and fed-batch culture of baculovirus-infected insect cells. Cytotechnology 2011; 34:71-82. [PMID: 19003382 DOI: 10.1023/a:1008178029138] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The infection of insect cells with baculovirus was described in a mathematical model as a part of the structured dynamic model describing whole animal cell metabolism. The model presented here is capable of simulating cell population dynamics, the concentrations of extracellular and intracellularviral components, and the heterologous product titers. The model describes the whole processes of viral infection and theeffect of the infection on the host cell metabolism. Dynamic simulation of the model in batch and fed-batch mode gave goodagreement between model predictions and experimental data. Optimum conditions for insect cell culture and viral infectionin batch and fed-batch culture were studied using the model.
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Common association of haemolytic uraemic syndrome with invasive Streptococcus pneumoniae infection in five Chinese paediatric patients. Hong Kong Med J 2011; 17:237-241. [PMID: 21636872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023] Open
Abstract
Haemolytic uraemic syndrome is an important cause of acute renal impairment in childhood. We review the incidence, and clinical and laboratory features of haemolytic uraemic syndrome in a Chinese population. Five patients were identified from 2006 to 2008. All patients were young children with associated invasive Streptococcus pneumoniae pulmonary infection. Serotypes 3, 14, and 19A were confirmed in four patients. The classical post-diarrhoeal form associated with Escherichia coli (O157:H7) infection was not seen. One patient died of acute respiratory failure. Streptococcus pneumoniae infection, as an associated condition in haemolytic uraemic syndrome, is important and relatively common in Chinese patients, especially among children. The acute clinical picture is similar to that reported in the western literature, except for an uncommon association with meningitis. The medium-term renal outcome of the Chinese population appears to be more favourable than the Caucasians. Widespread vaccination against Streptococcus pneumoniae may have resulted in changes in bacterial epidemiology and clinicians should be continuously aware of this severe disease. The use of washed blood components for transfusion in the acute stage requires further study.
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Stereotactic radiotherapy for hepatocellular carcinoma: report of a local single-centre experience. Hong Kong Med J 2011; 17:112-118. [PMID: 21471590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023] Open
Abstract
OBJECTIVE To evaluate the efficacy and toxicities of stereotactic radiotherapy for unresectable hepatocellular carcinoma. DESIGN Retrospective study. SETTING Prince of Wales Hospital, Hong Kong. MAIN OUTCOME MEASURES Treatment outcome and toxicities. PATIENTS During the period of 2000 to 2004, 16 patients with hepatocellular carcinoma treated with stereotactic radiotherapy were reviewed. RESULTS Of the 16 patients, 11 had assessable responses. For local control, there were two complete and three partial responses, five with stable disease and one with progressive disease, giving a local response rate of 45% and control rate of 91%. The median survival was 23 months. The 1-year and 3-year overall survival rates were 62% and 28%, respectively. The most frequent site of recurrence was intrahepatic but outside the irradiated field. Two patients with Child-Pugh B cirrhosis developed radiation-induced liver disease. No other grade 3/4 toxicities were recorded. CONCLUSION Stereotactic radiotherapy gives high local control rates and has the potential to prolong survival in patients with hepatocellular carcinoma. It is safe and tolerable in Child-Pugh A patients.
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Young Chinese medical students adapt well to problem-based learning. MEDICAL TEACHER 2011; 33:506. [PMID: 21609179 DOI: 10.3109/0142159x.2011.586615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
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Detection and characterisation of -globin gene cluster deletions in Chinese using multiplex ligation-dependent probe amplification. J Clin Pathol 2009; 62:1107-11. [DOI: 10.1136/jcp.2009.067538] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Abstract
Chromosomal rearrangements of the human MLL gene are associated with high-risk pediatric, adult and therapy-associated acute leukemias. These patients need to be identified, treated appropriately and minimal residual disease was monitored by quantitative PCR techniques. Genomic DNA was isolated from individual acute leukemia patients to identify and characterize chromosomal rearrangements involving the human MLL gene. A total of 760 MLL-rearranged biopsy samples obtained from 384 pediatric and 376 adult leukemia patients were characterized at the molecular level. The distribution of MLL breakpoints for clinical subtypes (acute lymphoblastic leukemia, acute myeloid leukemia, pediatric and adult) and fused translocation partner genes (TPGs) will be presented, including novel MLL fusion genes. Combined data of our study and recently published data revealed 104 different MLL rearrangements of which 64 TPGs are now characterized on the molecular level. Nine TPGs seem to be predominantly involved in genetic recombinations of MLL: AFF1/AF4, MLLT3/AF9, MLLT1/ENL, MLLT10/AF10, MLLT4/AF6, ELL, EPS15/AF1P, MLLT6/AF17 and SEPT6, respectively. Moreover, we describe for the first time the genetic network of reciprocal MLL gene fusions deriving from complex rearrangements.
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An unbalanced translocation, der(17)t(1;17)(p13;p11.2), leads to heterozygous loss of TP53 and is associated with clinical evolution in myelodysplastic syndrome. Br J Biomed Sci 2008; 65:36-8. [PMID: 18476495 DOI: 10.1080/09674845.2008.11978107] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Double heterozygosity for Hb New York [beta 113 GTG-->GAG; VAL-->GLU] and beta degrees-thalassemia mutations manifests as a thalassemia trait. Pediatr Hematol Oncol 2008; 25:227-31. [PMID: 18432506 DOI: 10.1080/08880010801938199] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
An extended family with three individuals affected by two different forms of double heterozygosity for beta-thalassemia and Hb New York is reported. Double heterozygosity of Hb New York [beta 113 GTG-->GAG; VAL-->GLU] and beta degrees codon 17 was detected in a fetus following prenatal screening for thalassemia. The father and a paternal aunt were also found to be heterozygous for Hb New York and beta degrees IVSII-654. Both adults had clinical and hematological features consistent with beta-thalassemia trait. The affected child was followed up after birth and manifested the typical course of a thalassemia trait, with no signs of organomegaly or overt hemolysis. Observations strongly suggest that double heterozygosity of Hb New York and beta degrees thalassemia has mild, if any, clinical symptoms, and is not an indication of therapeutic abortion when detected antenatally.
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Functional alterations of Lin-CD34+CD38+ cells in chronic myelomonocytic leukemia and on progression to acute leukemia. Leuk Res 2008; 32:1374-81. [PMID: 18372040 DOI: 10.1016/j.leukres.2008.02.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2007] [Revised: 01/15/2008] [Accepted: 02/13/2008] [Indexed: 10/22/2022]
Abstract
The functional behavior of hematopoietic stem cell (HSC) and progenitors in chronic myelomonocytic leukemia (CMML) and on disease progression is little known. We performed cell proliferation, apoptosis, hematopoietic colony forming/replating and differentiation potential studies in the purified subpopulations of Lin(-)CD34(+)CD38(-) and Lin(-)CD34(+)CD38(+) cells from 16 CMML with 6 cases after acute myeloid leukemia transformation (AML-t). We observed an expansion of the hematopoietic progenitor pool (Lin(-)CD34(+) cells) in AML-t comprising mainly Lin(-)CD34(+)CD38(+) cells. The Lin(-)CD34(+)CD38(+) cells in AML-t displayed high proliferative activity, resistance to apoptosis, enhanced myeloid colony formation/replating ability and a complete dendritic cell (DC) differentiation block. Our findings suggest Lin(-)CD34(+)CD38(+) cells instead of Lin(-)CD34(+)CD38(-) cells could be the target(s) of secondary genetic lesions underpinning progression from CMML to AML, which have implications for the further study of the biology of leukemic transformation and the design of new strategies for the effective treatment of CMML.
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Aberrant dendritic cell differentiation initiated by theMll-Eenfusion gene does not require leukemic transformation. J Leukoc Biol 2007; 83:173-80. [PMID: 17895399 DOI: 10.1189/jlb.0607348] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Dendritic cells (DCs), as specialized APCs, play a key role in the induction of anti-tumor immunity. They originate from bone marrow (BM) progenitors, which are frequently the targets of chromosomal translocations leading to development of leukemia. Aberrant DC differentiation and functions have been observed and are widely reported in patients with leukemia. It is not clear, however, whether such defects are a direct effect of a leukemic fusion gene or simply an outcome of the clinical disease. In this study, we demonstrate for the first time that knockin of the Mll-Een fusion gene can affect myeloid DC differentiation and functions directly, independent of the leukemic disease activities. We showed that the Mll-Een-expressing BM cells [enhanced green fluorescent protein+ (EGFP+)] from leukemic and nonleukemic mice had similarly impaired DC differentiation capacities with functional abnormalities. In contrast, BM cells without Mll-Een expression (EGFP(-)) showed normal DC differentiation and functions. A reduction in the frequency of CD11c+ DCs was also observed within the EGFP+ population in spleen and lymph nodes, and these cells were dysfunctional. Taken together, our findings suggest that the Mll-Een fusion gene can affect myeloid DC differentiation directly and functions in a cell-autonomous manner, where fully leukemic transformation of the hematopoietic progenitors is not required exclusively. Therefore, the study provides evidence for a direct causal relationship between leukemic gene fusion and abnormal DC differentiation, possibly contributing to the development of leukemia.
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LPA3 receptor mediates chemotaxis of immature murine dendritic cells to unsaturated lysophosphatidic acid (LPA). J Leukoc Biol 2007; 82:1193-200. [PMID: 17709403 DOI: 10.1189/jlb.0407221] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Increasing evidence supports roles for lipids in the biology of immune cells. In particular, bioactive lipids such as sphingosine-1-phosphate (S1P) bind to cognate G protein-coupled receptors (GPCRs) and modulate leukocyte trafficking and homeostasis. Lysophosphatidic acid (LPA) represents a family of bioactive lipids, which differ in the length and degree of saturation of the fatty acyl chain. LPA is structurally related to S1P and exerts cellular effects by binding to five known GPCRs (LPA(1-5)). Its function in the immune system is less clear, although it was shown to induce chemotaxis of human dendritic cells (DCs) and activated T cells. In this study, we show that LPA can induce chemotaxis of immature but not mature mouse DCs and that only unsaturated and not saturated LPA species are efficient chemoattractants. However, both LPA species do not alter DC maturation or chemotaxis to other chemokines. The loss of DC migration capability correlated with the down-regulation of expression of the receptors LPA(3) and LPA(5), and expression of LPA(1), LPA(2), and LPA(4) did not change. A LPA(3) antagonist reduced immature DC migration to LPA by 70%, suggesting that LPA(3) mediates immature DC chemotaxis to unsaturated species of LPA. Furthermore, isolated, immature DCs from mice lacking LPA(3) exhibited a 50% reduction in migration to LPA. In summary, our results indicate that immature mouse DCs migrate preferentially in response to unsaturated LPA and that LPA(3) is important in this response.
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Philadelphia chromosome unmasked as a secondary genetic change in acute myeloid leukemia on imatinib treatment. Leukemia 2006; 20:2050-1. [PMID: 17024117 DOI: 10.1038/sj.leu.2404407] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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The Mll-Een knockin fusion gene enhances proliferation of myeloid progenitors derived from mouse embryonic stem cells and causes myeloid leukaemia in chimeric mice. Leukemia 2006; 20:1829-39. [PMID: 16888613 DOI: 10.1038/sj.leu.2404342] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Rearrangement of the mixed lineage leukaemia (MLL) gene with extra eleven nineteen (EEN) was previously identified in an infant with acute myeloid leukaemia. Using homologous recombination, we have created a mouse equivalent of the human MLL-EEN allele and showed that when Mll(Een/+) embryonic stem (ES) cells were induced to differentiate in vitro into haemopoietic cells, there was increased proliferation of myeloid progenitors with self-renewal property. We also generated Mll(Een/+) chimeric mice, which developed leukaemia displaying enlarged livers, spleens, thymuses and lymph nodes owing to infiltration of Mll(Een/+)-expressing leukemic cells. Immunophenotyping of cells from enlarged organs and bone marrow (BM) of the Mll(Een/+) chimeras revealed an accumulation of Mac-1+/Gr-1- immature myeloid cells and a reduction in normal B- and T-cell populations. We observed differential regulation of Hox genes between myeloid cells derived from Mll(Een/+) ES cells and mouse BM leukemic cells which suggested different waves of Hox expression may be activated by MLL fusion proteins for initiation (in ES cells) and maintenance (in leukemic cells) of the disease. We believe studies of MLL fusion proteins in ES cells combined with in vivo animal models offer new approaches to the dissection of molecular events in multistep pathogenesis of leukaemia.
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Improved outcome of acute lymphoblastic leukaemia treated by delayed intensification in Hong Kong children: HKALL97 study. Hong Kong Med J 2006; 12:33-9. [PMID: 16495587 DOI: pmid/16495587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
OBJECTIVE To study the outcome of children with acute lymphoblastic leukaemia who were treated using a protocol including one or two delayed intensifications. DESIGN Prospective single-arm multicentre study. SETTING Five designated children cancer units of the Hospital Authority of Hong Kong. PATIENTS Children aged between 1 and 17.9 years with newly diagnosed acute lymphoblastic leukaemia seen from November 1997 to December 2002. INTERVENTION Chemotherapy was modified from a German Berlin-Frankfurt-Muenster 95 (BFM95) protocol that included a delayed intensification similar to the induction phase repeated 5 months after diagnosis. High-risk patients were given double delayed intensification. MAIN OUTCOME MEASURES Overall survival and event-free survival of the whole group and the three risk groups (standard-, intermediate-, and high-risk groups), and comparison with historical controls. RESULTS A total of 171 patients were recruited with a median age at diagnosis of 5.57 years (range, 1.15-17.85 years). The induction remission rate was 95.3% and non-leukaemia mortality during remission was 2.3%. At 4 years, the relapse rate of this (HKALL97) study was significantly lower than that of the HKALL93 study (15.7 vs 37.3%; P<0.001). The 4-year overall survival of HKALL97 and HKALL93 studies were 86.5% and 81.8%, respectively (P=0.51). The 4-year event-free survival for HKALL97 and HKALL93 studies were 79% and 65%, respectively (P=0.007). Nonetheless the difference of event-free survival was most remarkable in the intermediate-risk group: 75.6% and 53.1% for HKALL97 and HKALL93 studies, respectively (P=0.06). CONCLUSION A more intensive delayed consolidation phase improved the outcome for children with acute lymphoblastic leukaemia by reducing relapses at 4 years. The early treatment complications were manageable and non-leukaemia mortality during remission remained low.
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Abstract
AIM To assess the ability of nurse practitioners to manage the care of all babies requiring resuscitation at birth in a unit without on site medical assistance. METHOD A prospective review, and selective external audit, of the case records of all 14 572 babies born in a maternity unit in the north of England during the first eight years after nurse practitioners replaced resident paediatric staff in 1996. RESULTS Every non-malformed baby with an audible heart beat at the start of delivery was successfully resuscitated. Twenty term babies and 41 preterm babies were intubated at birth. Eight term babies only responded after acidosis or hypovolaemia was corrected following umbilical vein catheterisation; in each case the catheter was in place within six minutes of birth. Early grade 2-3 neonatal encephalopathy occurred with much the same frequency (0.12%) as in other recent studies. Independent external cross validated review found no case of substandard care during the first hour of life. CONCLUSION The practitioners successfully managed all the problems coming their way from the time of appointment. There was no evidence that their skill decreased over time even though, on average, they only found themselves undertaking laryngeal intubation once a year. It remains to be shown that this level of competence can be replicated in other settings.
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Trisomy 4 as sole karyotypic abnormality in acute lymphoblastic leukemia: Different clinical features and treatment response between B and T phenotypes? ACTA ACUST UNITED AC 2006; 164:94-5. [PMID: 16364773 DOI: 10.1016/j.cancergencyto.2005.07.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2005] [Revised: 06/30/2005] [Indexed: 10/25/2022]
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Abstract
There has been much recent attention on psychological well-being and pastoral care for medical students. This study examines psychological morbidity (depression, anxiety and stress) in Hong Kong medical students, as well as their concerns, coping mechanisms and their help-seeking. Medical students in Hong Kong reported a higher level of psychological morbidity as compared with other tertiary education students. Their main concerns include examinations, stress, career, adjusting to the new medical curriculum and commitment to the course. The coping skills adopted were largely adaptive. Maladaptive coping skills like 'denial', 'self-blame' and 'behavioural disengagement' were highly correlated with depression, anxiety and stress scores. Most of the students concerned wanted support services that were specifically tailored to their needs and at least partly provided by people who had been through medical training themselves. The faculty at the University of Hong Kong is establishing a Programme for Effective Transition and Student Support (PETSS) to provide a multi-faceted support system for its medical students. The findings in this study help to ensure that the services provided will be relevant, accessible and acceptable to the students.
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Investigation of MYCN status in neuroblastoma by fluorescence in situ hybridization. Int J Mol Med 2004; 14:981-7. [PMID: 15547663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2023] Open
Abstract
Neuroblastoma, a form of neuroblastic tumor, is one of the most common neoplasms seen in early childhood. The diverse clinical behavior of this tumor is most probably explainable by the heterogeneity in the associated genetic changes. We investigated 12 neuroblastoma patients for MYCN amplification and chromosome 2 aneusomy by fluorescence in situ hybridization (FISH) and results were correlated with conventional cytogenetics. Samples from both primary tumor tissue and bone marrow metastasis were available in two cases. The copy number of MYCN oncogene paralleled that of chromosome 2 in 10 cases, whereas two cases (16.7%) showed numerous distinct signals within the nuclei of the tumor cells, consistent with MYCN amplification as double minute (dmin). The morphology of dmin in one case was of an extremely small type and might potentially be missed by conventional chromosome analysis. Discordant cytogenetics and FISH results was observed between primary tumor and metastasis disease in one case, with loss of chromosome 2 tetrasomic and pentasomic cells as well as over-representation of chromosome 2 disomic cells harboring MYCN amplification in bone marrow deposits. Our study reaffirmed the need for MYCN status to be determined in light of chromosome 2 copy number, as recommended by published guidelines. We also showed that genetic heterogeneity might occur between primary tumor and bone marrow metastasis. Finally, atypical dmin morphology when encountered would need confirmation by FISH study.
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Pathogenesis of jumping translocations: a molecular cytogenetics study. Leuk Res 2004; 28:1075-9. [PMID: 15289020 DOI: 10.1016/j.leukres.2004.01.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2003] [Accepted: 01/14/2004] [Indexed: 10/26/2022]
Abstract
BACKGROUND/AIMS Jumping translocations are rare cytogenetic aberrations in haematological malignancies, the pathogenesis of which remains to be fully characterised. We investigated the mechanism of formation of jumping translocations in a case of adult common acute lymphoblastic leukaemia (ALL) positive for the Ph translocation. METHODS Interphase and metaphase fluorescence in situ hybridisation (FISH) was performed using several probe systems. Results were correlated with findings on conventional cytogenetics. Granulocytes, T-cells and leukaemic B-cells in peripheral blood were sorted by immunomagnetic method and the terminal restriction fragment (TRF) length of these cellular populations was determined by Southern blot analysis. RESULTS Duplicated BCR-ABL fusion signals were found on a dic(14;22)der(22)t(9;22) chromosome. Clonal jumping translocations, existing as evolutionary changes, involved the donor chromosomal segment distal to 1q12 jumping onto the telomere ends of 11q, 15p, 19p and 20p. Telomere length was decreased in the neoplastic B-cell population and contributed to the formation of the dicentric chromosome that showed absence of telomere repeats at fusion ends. Subsequent pericentromeric heterochromatin decondensation of chromosome 1q occurred, and this donor segment was randomly fused to the shortened telomere ends of non-homologous chromosomes. CONCLUSIONS Both telomere shortening and pericentromeric heterochromatin decondensation contribute to the formation of jumping translocations, which is most probably a multi-stage process.
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MESH Headings
- Antigens, CD/biosynthesis
- Antigens, Differentiation, Myelomonocytic/biosynthesis
- Blotting, Southern
- Chromosome Aberrations
- Chromosomes, Human, Pair 14/genetics
- Chromosomes, Human, Pair 22/genetics
- Chromosomes, Human, Pair 9/genetics
- Cytogenetic Analysis/methods
- Fatal Outcome
- Fusion Proteins, bcr-abl/genetics
- Humans
- In Situ Hybridization, Fluorescence/methods
- Male
- Middle Aged
- Polymorphism, Restriction Fragment Length
- Precursor Cell Lymphoblastic Leukemia-Lymphoma/diagnosis
- Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics
- Sensitivity and Specificity
- Sialic Acid Binding Ig-like Lectin 3
- Signal Transduction/genetics
- Telomere/genetics
- Translocation, Genetic/genetics
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Chloramphenicol succinate, a competitive substrate and inhibitor of succinate dehydrogenase: possible reason for its toxicity. Toxicol In Vitro 2004; 18:441-7. [PMID: 15130601 DOI: 10.1016/j.tiv.2003.12.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2003] [Accepted: 12/30/2003] [Indexed: 10/26/2022]
Abstract
From our previous study [Eur. J. Clin. Pharmacol. 56 (2000) 405] we hypothesized that chloramphenicol succinate (CAPS) may be a competitive substrate for succinate dehydrogenase (SDH). It may be oxidized by SDH to release chloramphenicol (CAP), which may inhibit SDH by feed back mechanism. The present ex-vivo/in vitro study was aimed to investigate this possibility by using human tissues (bone marrow and liver samples) and animal tissues (rat liver and kidney). The effect of different SDH activators and specific inhibitors was studied on CAPS metabolism by SDH. The metabolites and reduction products were detected by using HPLC. In marrow samples, CAPS was slowly oxidized to form CAP. The formation of CAP (oxidation product) was enhanced by FAD and low malonate and inhibited by high malonate and 3-NPA. Similar results were obtained with mitochondria from human and rat tissues. These studies suggest that CAPS could be a competitive oxidative substrate and the metabolite CAP could be an inhibitor at the reduction site. Therefore, SDH could be a target molecule responsible for CAPS induced toxicity.
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Abstract
Seven patients of Chinese origin who had haemoglobin (Hb) Q-H disease were studied. They were found to have a similar clinical phenotype to that of patients with deletional Hb H disease, who have a near identical genotypic configuration. The complete absence of Hb A in Hb Q-H disease and the similar clinical phenotype to deletional Hb H disease lends support to the observation that Hb Q-Thailand shares similar functional properties with Hb A.
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Atypical fluorescence in situ hybridisation pattern in chronic myeloid leukaemia due to cryptic insertion of BCR at 9q34. Leukemia 2004; 18:161-2; author reply 162-4. [PMID: 14603334 DOI: 10.1038/sj.leu.2403197] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Deletion 9q as the sole karyotypic abnormality in myelocytic disorders: a new case of myelodysplastic syndrome and its prognostic implications in acute myelocytic leukemia. CANCER GENETICS AND CYTOGENETICS 2003; 145:184-6. [PMID: 12935935 DOI: 10.1016/s0165-4608(03)00060-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Prevalence and specificity of clinically significant red cell alloantibodies in Chinese women during pregnancy--a review of cases from 1997 to 2001. Transfus Med 2003; 13:227-31. [PMID: 12880393 DOI: 10.1046/j.1365-3148.2003.00445.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Guidelines for the prevention and management of red cell alloantibodies during pregnancy, related to anti-D in particular, are well established in Caucasian populations. However, because of the racial difference of the blood group distribution, applicability to Chinese is unknown as a result of insufficient data on the prevalence and their outcome. In a retrospective review of 28,303 (21,327 Chinese) antenatal attendances from 1997 to 2001, 213 (0.79%) women were found to have a total of 230 irregular antibodies. About 137 (0.64%) were ethnic Chinese, and a total of 160 irregular antibodies were identified in their blood samples. About 58 of these Chinese women (0.27%) were found to have 66 clinically significant antibodies. There was only one case of anti-D detected in an Rh(D)-negative subject. Our study shows the overall prevalence of clinically significant antibodies in Chinese women, which was not different from that of the Western population. However, the specificities of the antibodies differ with the commonest antibodies encountered; these being anti-Mi (57.6%), anti-E (19.7%), anti-S (10.6%) and anti-c (7.6%). Neonatal jaundice was observed in 37 babies and 10 of them required phototherapy. The findings support the previous recommendation that routine antenatal antibody screening for Chinese women may not be worthwhile except in Rh(D)-negative subjects or those with an antecedent history of haemolytic disease of the newborn (HDN). The relative high incidence of anti-Mi in the present study and the local population, in general, may warrant a large-scale prospective study of pregnancy outcome in these subjects, especially in the light of the previous case reports of HDN because of anti-Mi.
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Derivative chromosome 9 deletions in chronic myeloid leukaemia: interpretation of atypical D-FISH pattern. J Clin Pathol 2003; 56:471-4. [PMID: 12783977 PMCID: PMC1769964 DOI: 10.1136/jcp.56.6.471] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND/AIMS New molecular cytogenetic techniques are increasingly applied as a routine investigative tool in haematological malignancies, both at diagnosis and subsequent monitoring. This report describes the interpretation of atypical signal patterns encountered using BCR-ABL dual colour dual fusion fluorescence in situ hybridisation (D-FISH) translocation probes in chronic myeloid leukaemia (CML). METHODS Interphase FISH experiments were carried out using BCR-ABL D-FISH probes in 46 patients with CML at diagnosis and during subsequent disease monitoring. Atypical hybridisation signal patterns were characterised by molecular cytogenetic techniques and correlated with conventional karyotyping. RESULTS Two patients showed atypical interphase D-FISH patterns with one orange, one green, and one fusion (1O1G1F) signal. The presence of BCR-ABL gene fusion was documented by a dual colour single fusion (S-FISH) probe. The submicroscopic deletion of the ABL-BCR fusion gene on the derivative chromosome 9 in these cases was subsequently characterised by metaphase FISH on relocated G banded metaphases. CONCLUSIONS Atypical interphase D-FISH patterns should not be interpreted in isolation and should be considered in conjunction with other cytogenetic or molecular genetic investigations.
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Venous thromboembolism in the Chinese population-experience in a regional hospital in Hong Kong. Hong Kong Med J 2003; 9:151. [PMID: 12668832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023] Open
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Trisomy 21 and other chromosomal abnormalities in acute promyelocytic leukemia. CANCER GENETICS AND CYTOGENETICS 2003; 140:170-3. [PMID: 12645658 DOI: 10.1016/s0165-4608(02)00684-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We describe a case of acute promyelocytic leukemia (APL) with t(15;17)(q22;q12) and trisomy 21 as an additional change in a patient who died at relapse after achieving complete remission (CR) for the duration of 20 months. A survey of 42 cases of APL with cytogenetic study performed at our institutionover the past 10 years showed 12 cases (28.6%) having chromosomal changes in addition to t(15;17). Trisomy 8 and trisomy 21 as additional changes were noted in 4 and 2 cases, respectively, with one patient showing both trisomies simultaneously. Two cases showed t(15;17) in hyperdiploid clones. Among the 10 patients with follow-up data, all eventually relapsed and none achieved continuous complete remission 1. Survival analysis performed in APL patients with adequate follow-up data showed no significant difference in overall and disease free survival between those with and without additional cytogenetic changes. After excluding cases with one induction death, the overall survival was significantly in favor of the group without additional cytogenetic abnormalities (P = 0.022). Late relapses may therefore be significantly more common in APL patients with additional cytogenetic abnormalities, and may not be reflected by analysis focused at three-year survival only. As APL is now considered a curable disease, any confirmed long-term survival impact of additional cytogenetic changes is expected to have important management implications.
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MESH Headings
- Adolescent
- Adult
- Antineoplastic Agents/therapeutic use
- Chromosome Aberrations
- Chromosome Banding
- Chromosomes, Human, Pair 15/ultrastructure
- Chromosomes, Human, Pair 17/ultrastructure
- Chromosomes, Human, Pair 21
- Death, Sudden
- Fatal Outcome
- Female
- Hong Kong/epidemiology
- Humans
- Leukemia, Promyelocytic, Acute/drug therapy
- Leukemia, Promyelocytic, Acute/genetics
- Leukemia, Promyelocytic, Acute/mortality
- Male
- Middle Aged
- Pulmonary Embolism/etiology
- Remission Induction
- Retrospective Studies
- Survival Analysis
- Translocation, Genetic
- Tretinoin/therapeutic use
- Trisomy
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Two balanced and novel chromosomal translocations in myeloid malignancies. characterization by multiplex fluorescence in situ hybridization. CANCER GENETICS AND CYTOGENETICS 2002; 139:52-6. [PMID: 12547159 DOI: 10.1016/s0165-4608(02)00611-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We describe two novel chromosomal translocations in two cases of leukemia in which these translocations were further characterized as the sole acquired karyotypic abnormality by mutliplex fluorescence in situ hybridization (M-FISH). They comprised a case of acute myeloid leukemia with t(6;10)(q21;p12) and a case of chronic myelomonocytic leukemia with t(5;12)(q34;q24). To the best of our knowledge, these two balanced translocations are novel and are hitherto unrecognized in hematologic malignancies. While the clinical and pathogenic significance of these translocations remains to be defined, the present report illustrates that M-FISH technology contributes to the exclusion of subtle or cryptic translocations in sole karyotypic aberrations and the confirmation of novel chromosomal arrangements in neoplastic disorders.
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MESH Headings
- Chromosome Mapping
- Chromosomes, Human, Pair 10
- Chromosomes, Human, Pair 12
- Chromosomes, Human, Pair 5
- Chromosomes, Human, Pair 6
- Humans
- In Situ Hybridization, Fluorescence/methods
- Karyotyping
- Leukemia, Myeloid, Acute/genetics
- Leukemia, Myelomonocytic, Chronic/genetics
- Translocation, Genetic
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Lineage-specific differences in telomere length after bone marrow transplantation. Bone Marrow Transplant 2002; 30:475-7. [PMID: 12368963 DOI: 10.1038/sj.bmt.1703669] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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