Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:5.99.1.3 (topoisomerase)
 9,911 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Streptococcus pneumoniae has been recognised as a major cause of pneumonia since the time of Sir William Osler. Drug-resistant S. pneumoniae (DRSP), which have gradually become resistant to penicillins as well as more recently developed macrolides and fluoroquinolones, have emerged as a consequence of indiscriminate use of antibacterials coupled with the ability of the pneumococcus to adapt to a changing antibacterial milieu. Pneumococci use cell wall choline components to bind platelet-activating factor receptors, colonise mucosal surfaces and evade innate immune defenses. Numerous virulence factors that include hyaluronidase, neuraminidase, iron-binding proteins, pneumolysin and autolysin then facilitate cytolysis of host cells and allow tissue invasion and bloodstream dissemination. Changes in pneumococcal cell wall penicillin-binding proteins account for resistance to penicillins, mutations in the ermB gene cause high-level macrolide resistance and mutations in topoisomerase IV genes coupled with GyrA gene mutations alter DNA gyrase and lead to high-level fluoroquinolone resistance. Risk factors for lower respiratory tract infections in the elderly include age-associated changes in oral clearance, mucociliary clearance and immune function. Other risks for developing pneumonia include poor nutrition, hypoalbuminaemia, bedridden status, aspiration, recent viral infection, the presence of chronic organ dysfunction syndromes including parenchymal lung disease and recent antibacterial therapy. Although the incidence of infections caused by DRSP is rising, the effect of an increase in the prevalence of resistant pneumococci on mortality is not clear. When respiratory infections occur, rapid diagnosis and prompt, empirical administration of appropriate antibacterial therapy that ensures adequate coverage of DRSP is likely to increase the probability of a successful outcome when treating community-acquired pneumonia in elderly patients, particularly those with multiple risk factors for DRSP. A chest x-ray is recommended for all patients, but other testing such as obtaining a sputum Gram's smear is not necessary and should not prolong the time gap between clinical suspicion of pneumonia and antibacterial administration. The selection of antibacterials should be based upon local resistance patterns of suspected organisms and the bactericidal efficacy of the chosen drugs. If time-dependent agents are chosen and DRSP are possible pathogens, dosing should keep drug concentrations above the minimal inhibitory concentration that is effective for DRSP. Treatment guidelines and recent studies suggest that combination therapy with a beta-lactam and macrolide may be associated with a better outcome in hospitalised patients, and overuse of fluoroquinolones as a single agent may promote quinolone resistance. The ketolides represent a new class of macrolide-like antibacterials that are highly effective in vitro against macrolide- and azalide-resistant pneumococci. Pneumococcal vaccination with the currently available polysaccharide vaccine is thought to confer some preventive benefit (preventing invasive pneumococcal disease), but more effective vaccines, such as nonconjugate protein vaccines, need to be developed that provide broad protection against pneumococcal infection.
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PMID:Drug treatment of pneumococcal pneumonia in the elderly. 1549 50

Scleroderma (systemic sclerosis) is characterized by dermal thickening and is subclassified, on the basis of the pattern of skin involvement, as diffuse or limited cutaneous disease. The lung fibrosis associated with systemic sclerosis is histopathologically nonspecific interstitial pneumonia and occurs to various extents. A key determinant of the development of lung fibrosis is the carriage of the anti-DNA topoisomerase II autoantibody, which is driven by genotype, particularly major histocompatibility complex class II alleles. Epithelial and endothelial cell injury initiates lung pathology and the local milieu expresses all the expected components of an immune/inflammatory chronic process that has fibrosis as an associated feature. However, novel concepts of the pathogenesis include the role of epithelial mesenchymal transition as a source of myofibroblasts following epithelial cell triggering and the concept of fibroblast heterogeneity in terms of both origin and function. Focus on the poles of the pathogenetic process, than on the redundancy of multiple mediator pathways, may provide more translational ideas in terms of elucidating how epithelial triggering initiates the downstream events and how fibroblast proliferation and connective matrix deposition is controlled, together with establishing how the process of autoantibody formation relates to the pathophysiologic events. Although much remains to be learned about the mechanisms of scleroderma-induced lung disease the clarity of the questions is improving.
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PMID:Mechanisms of scleroderma-induced lung disease. 1768 84

The objective of this study was to determine clinical predictors of interstitial lung disease in patients with systemic sclerosis (SSc) and pulmonary involvement as defined by presence of a decreased diffusing capacity for carbon monoxide (DLCO). Forty subjects with SSc were retrospectively evaluated. Patients were categorized according to their level of DLCO (< o > or = 80% of predicted). Sensitivity of dyspnea to detect a decreased DLCO was 46.6% and specificity 90%, whereas oxygen desaturation showed a sensitivity of 71.4% and a specificity of 80%. Patients with decreased DLCO (n = 18) were not different in age (51.1 +/- 13.5 vs. 53.5 +/- 9.3 y, p = 0.5182), sex (male 13.6%, p = 0.6088), prevalence of Raynaud (86.6% vs. 85%, p = 0.6272), sicca syndrome (6.2% vs. 10.5% p = 1.0000) diffuse cutaneous involvement (94.1% vs. 83.3%, p = 0.6026) or esophageal dilatation. The duration of symptoms since diagnosis was no different. Prevalence of pulmonary hypertension assessed by Doppler echocardiography or abnormal nailfold capillaroscopic findings were identical in both populations. Patients with low DLCO had a significatly higher prevalence of anti topoisomerase antibodies. (5/9 vs. 0/11, p = 0.0081) and restrictive lung disease. Patients with low DLCO showed a significantly higher prevalence of abnormal HRCT findings suggestive of ILD (82.3% vs. 5.8%, p < or = 0.0001). We conclude that a low DLCO is a frequent finding in SSc patients, strongly associated with HRCT signs of ILD. We have not found clinical factors predictive for a low DLCO.
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PMID:[Lung involvement in systemic sclerosis]. 1805 Dec 24

Systemic sclerosis is a connective tissue disease characterized by progressive skin thickening and a wide spectrum of internal organ involvement. Pathogenesis includes vasculopathy, inflammation, and fibrosis. Although immunosuppressants such as cyclophosphamide and mycophenolate mofetil have shown some benefit in interstitial lung disease management, it is still a major cause of morbi-mortality in these patients. Therefore, there is a current need for new therapies. Here, we report a 65-year-old female patient with limited cutaneous systemic sclerosis, anti-topoisomerase-positive and extensive lung disease. The patient developed progressive lung fibrosis under several immunosuppressants and was started on nintedanib, with clinical and functional stabilization. Nintedanib is a tyrosine-kinase inhibitor that blocks several profibrotic pathways, inhibiting proliferation and migration of fibroblasts and decreasing the synthesis of extracellular matrix proteins. It is approved for idiopathic lung fibrosis and has demonstrated good results in inhibiting migration and proliferation of systemic sclerosis dermal fibroblasts, constituting a promising agent for systemic sclerosis-associated lung fibrosis.
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PMID:Anti-fibrotic nintedanib-a new opportunity for systemic sclerosis patients? 2903 68