Cyril Valentine Shanahan
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PROVIDER: S-EPMC1124345 | biostudies-literature | 2002 Oct
REPOSITORIES: biostudies-literature
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| S-EPMC1124181 | biostudies-literature
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| S-EPMC1363963 | biostudies-literature
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| S-EPMC3320394 | biostudies-literature
Project description:BackgroundMortality from myocardial infarction (MI) has been decreasing since the introduction of primary percutaneous intervention. Late complications still pose a dilemma, such as deterioration of left ventricle (LV) function, LV aneurysms, and LV thrombus formation. If not adequately managed in a timely manner, this can result in life-threatening consequences. Restoration of LV function by surgical resection of the infarcted LV wall is an option for a few complicated cases, with variable outcomes.Case summaryA 66-year-old man presented with dyspnoea 2 years after his initial MI, which was treated with a drug-eluting stent to his left circumflex artery. His Warfarin had been stopped after 6 months of treatment of a small LV thrombus, which was noted at the time of his initial infarction. His echocardiogram on admission demonstrated severe LV systolic impairment of 23% (which had deteriorated from 40%) with a giant true aneurysm of the basal to mid-lateral wall, which resembled a Valentine heart. The presence of a large, organized thrombus filling the aneurysm complicated the case further. The patient underwent a resection of the LV aneurysm and thrombus. He remained asymptomatic and maintained a significant improvement of his LV function to 47% at his 5 months scan.DiscussionThe importance of imaging post-large MI and follow-up imaging once thrombus resolution has occurred is crucial. Patients with large LV aneurysm associated with severe refractory LV impairment and LV thrombus should be considered for LV aneurysmectomy for prognostic benefit and symptom relief.
| S-EPMC9382566 | biostudies-literature
Project description:Panton-valentine leukocidin (PVL) has been linked to worldwide emergence of community-associated methicillin resistant Staphylococcus aureus (CA-MRSA) -- its role in virulence in unclear. Here we show that PVL had no effect on global gene expression of prominent CA-MRSA strains nor did it affect bacterial clearance from lungs, spleen and kidneys in a highly discriminatory rabbit bacteremia model. These findings negate a large body of epidemiological research that implicated PVL in CA-MRSA virulence. Keywords: mutant vs wild type in 2 different growth phases grown in 2 different medias
2008-09-12 | GSE8677 | GEO
Project description:The binding of the S component (LukS-PV) from the bicomponent staphylococcal Panton-Valentine leucocidin to human polymorphonuclear neutrophils (PMNs) and monocytes was determined using flow cytometry and a single-cysteine substitution mutant of LukS-PV. The mutant was engineered by replacing a glycine at position 10 with a cysteine and was labeled with a fluorescein moiety. The biological activity of the mutant was identical to that of the native protein. It has been shown that LukS-PV has a high affinity for PMNs (Kd = 0.07 +/- 0.02 nM, n = 5) and monocytes (Kd = 0.020 +/- 0.003 nM, n = 3) with maximal binding capacities of 197,000 and 80,000 LukS-PV molecules per cell, respectively. The nonspecifically bound molecules of LukS-PV do not form pores in the presence of the F component (LukF-PV) of leucocidin. LukS-PV and HlgC share the same receptor on PMNs, but the S components of other staphylococcal leukotoxins, HlgA, LukE, and LukM, do not compete with LukS-PV for its receptor. Extracellular Ca2+ at physiological concentrations (1 to 2 nM) has only a slight influence on the LukS-PV binding, in contrast to its complete inhibition by Zn2+. The down-regulation by phorbol 12-myristate 13-acetate (PMA) of the binding of LukS-PV was blocked by staurosporine, suggesting that the regulatory effect of PMA depends on protein kinase C activation. The labeled mutant form of LukS-PV has proved very useful for detailed binding studies of circulating white cells by flow cytometry. LukS-PV possesses a high specific affinity for a unique receptor on PMNs and monocytes.
| S-EPMC98170 | biostudies-literature
Project description:We determined the entire nucleotide sequence of phiSa2958-carrying Panton-Valentine leukocidin (PVL) gene, which was lysogenized in a sequence type 5 staphylococcal cassette chromosome mec (SCCmec) type II strain of methicillin-resistant Staphylococcus aureus (MRSA). Based on the nucleotide sequences of PVL phages, we developed PCRs to discriminate among five PVL phages, with a preliminary classification into two morphological groups (elongated-head type and icosahedral-head type) with four PCRs, including two PCRs for identifying the gene lineage between lukS-PV and the tail gene. The phages were then classified into five types by four PCRs identifying each phage-specific structure. With these PCRs, we examined the PVL phage types of 67 MRSA strains isolated in Japan from 1979 through 1985 and since 2000 and found that two morphologically distinct phages were predominant in Japan. The icosahedral-head-type phage, represented by the phi108PVL type, was identified for 39 of 53 strains isolated from 1979 through 1985. Of 26 other Japanese isolates, 25 belonged either definitively or presumably to elongated-head types as follows: 3 belonged to the phiSa2958 type; 8 were determined to belong to an elongated-head type, but a determination of greater specificity was not made; and 14 belonged to a phiSa2958-like phage of unknown type. We induced prophages by treatment with mitomycin C from six strains of the phiSa2958 type or of phiSa2958-like unknown-type phages; five of six strains carried intact PVL-carrying phages, which can infect other S. aureus strains and might generate novel PVL-positive strains of S. aureus. That various SCCmec elements were carried by different strains of the same phage type suggests that S. aureus strains might independently acquire PVL phages before they acquire various SCCmec elements.
| S-EPMC2566072 | biostudies-literature