Prevalence of phenotypic resistance of Staphylococcus aureus isolates to macrolide,lincosamide, streptogramin B,ketolid and linezolid antibiotics in Turkey

The incidence of drug-resistant pathogens differs greatly between countries according to differences in the usage of antibiotics. The purpose of this study was to investigate the phenotypic resistance of 321 methicillin resistance Staphylococcus aureus (MRSA) and 195 methicillin susceptible S. aureus (MSSA) in a total of 516 S. aureus strains to macrolide, lincosamide, streptogramin B (MLS_B), ketolid, and linezolid. Disk diffusion method was applied to determine MLS_B phenotype and susceptibility to different antibiotic agents. It was found that 54.6% of the isolates were resistant to erythromycin (ERSA), 48% to clindamycin, 55% to azithromycin, 58.7% to spiramycin, 34.7% to telithromycin, and 0.4% to quinupristin-dalfopristin, respectively. No strain resistant to linezolid was found. The prevalence of constitutive (cMLS_B), inducible (IMLS_B), and macrolides and type B streptogramins (M/MS_B) among ERSA isolates (237 MRSA, 45 MSSA) was 69.6%, 18.2%, and 12.2% in MRSA and 28.9%, 40%, and 31.1% in MSSA, respectively. In conclusions, the prevalence of cMLS_B was predominant in MRSA; while in MSSA strains, iMLS_B and M/MS_B phenotype were more higher than cMLS_B phenotype resistance. The resistance to quinupristindalfopristin was very low, and linezolid was considered as the most effective antibiotic against all S.aureus strains.     

Antiplatelet effect of once- or twice-daily aspirin dosage in stable coronary artery disease patients with diabetes

The aim of this pilot study was to compare the effect of two different regimens of aspirin dosage on platelet of coronary artery disease (CAD) diabetic patients. Twenty-five CAD diabetic patients were included. Initially, all patients received aspirin 100 mg/day for 10 days. At day 10, aspirin antiplatelet effect was determined by measuring the collagen/epinephrine closure time (CT) 2 h after the last aspirin dosage and the next morning at 8 a.m.. The aspirin regimen was modified to 100 mg twice daily for patients showing a non-optimal platelet-inhibitory effect (CT < 298 s at 8 a.m.). Persistent high platelet reactivity (HPR) was defined by a CT < 160 s. During the 100 mg/day aspirin regimen, the prevalence of HPR at 8 a.m. was 48%, and only 7 patients (28%) had showed an optimal platelet-inhibitory effect. Bridging to the twice-daily regimen, the HPR was significantly reduced (p = 0.025), and the optimal platelet-inhibitory effect was reached for 3 other patients. Our results showed that 100 mg aspirin twice-daily dosing rather than a once-daily dose significantly improves the aspirin effect on platelet of CAD diabetic patients. However, large prospective studies were needed to confirm whether this strategy will be clinically relevant and safe.     

Mechanism of Alternariol monomethyl ether-induced mitochondrial apoptosis in human colon carcinoma cells

Alternariol monomethyl ether (AME) is a major mycotoxin produced by fungi of the genus Alternaria and a common contaminant of food products such as fruits and cereals worldwide. AME can cause serious health problems for animals as well as for humans. In this study, human colon carcinoma cells (HCT116) were used to explore the mechanisms of cell death induced by AME. Exposure of HCT116 cells to AME resulted in significant cytotoxicity manifested by a loss in cell viability mainly mediated by activation of apoptotic process. AME activated the mitochondrial apoptotic pathway evidenced by the opening of the mitochondrial permeability transition pore (PTP), loss of the mitochondrial transmembrane potential (ΔΨm) downstream generation of O(2)(-), cytochrome c release and caspase 9 and 3 activation. Experiments conducted on isolated organelles indicated that AME does not directly target mitochondria to induce PTP-dependent permeabilization of mitochondrial membranes. Moreover, no difference was observed in Bax-KO cells in comparison to parental cells, suggesting that the pro-apoptotic protein Bax is not involved in AME-induced mitochondrial apoptosis. Our findings demonstrate for the first time that AME induces cell death in human colon carcinoma cells by activating the mitochondrial pathway of apoptosis.     

Protective effects of selenium on methimazole-induced anemia and oxidative stress in adult rats and their offspring

The present study investigates the potential ability of selenium, considered as an antioxidant with pharmacological property to alleviate oxidative stress and hematological parameter disorders induced by methimazole, an antithyroid drug. Pregnant Wistar rats were randomly divided into four groups of six each: group I served as negative control and received a standard diet; group II received 250 mg/L of methimazole in drinking water and a standard diet; group III received both methimazole (250 mg/L, orally) and selenium (0.5 mg/kg of diet) supplemented to the standard diet; group IV served as positive control and received a supplement of selenium in the diet (0.5 mg/kg of diet) as sodium selenite (Na(2)SeO(3)). Treatment was started from the 14th day of pregnancy until day 14 after delivery. Methimazole reduced the number of red blood cells, hemoglobin concentration and hematocrit in mothers and their pups. Besides, plasma iron, vitamins B(9), B(12), C and E levels were reduced. Lipid peroxidation increased, objectified by high malondialdehyde levels and lactate dehydrogenase activity in plasma, while glutathione, glutathione peroxidase, superoxide dismutase and catalase activities showed a significant decline. Co-administration of selenium through diet improved all the parameters cited above. It can be concluded that the administration of selenium alleviates methimazole-induced toxicity, thus demonstrating its antioxidant efficacy.     

An unusual lesion of the nasopharynx: oncocytic metaplasia

Oncocytic metaplasia of the nasopharynx is an exceptional lesion which exact etiopathogenesis, although largely discussed, still remains controversial. The purpose of this paper is to present the epidemiological characteristics and clinical signs of this lesion and to study its pathogenesis and its therapeutic modalities. We report two cases that occurred respectively in a 53- and 60-year-old woman. The first presented with pharyngeal dysesthesia and otalgia. The endoscopic examination revealed an irregularity of the posterior wall of the nasopharynx. The second patient presented with tinnitus, discomfort of the left ear and bilateral hearing loss. Endoscopic exam revealed a bilateral structural abnormality to the eardrum. Microscopy showed focal oncocytic metaplasia of the nasopharynx mucosa in both cases. There was a positive outcare for both patients after excisional biopsy. Oncocytic metaplasia seems to be in relation to the stimulation of sympathic neuropeptidergic nerve fibers which target epithelial, connective, endothelial and lymphoid cells.     

Development and evaluation of taste-masked drug for paediatric medicines - application to acetaminophen

The aim of this work was to produce and characterize taste-masked powders of a model drug (acetaminophen) prepared using potentially tolerable and safe excipients for paediatric use, i.e. sodium caseinate and lecithin. The powders were produced by spray-drying aqueous dispersions. The characteristics of taste-masked drug particles were determined by scanning electron microscopy, differential scanning calorimetry and X-ray photoelectron spectroscopy to analyse the surface composition of particles. Taste assessment was approached by an indirect method through drug release studies. We developed a method with a syringe pump using small volumes of aqueous medium and low flow rates, to mimic the behaviour in the mouth. This method was compared to the electronic tongue analysis. SEM, DSC and XPS analysis indicated differences in surface composition of spray-dried particles according to the caseinate/lecithin ratio and to relate it with taste-masking. The "coating" consisting of caseinate and lecithin had a significant role in decreasing the release of drug during the first 2 min and so in taste-masking. Higher content in lecithin results in higher taste-masking efficiency. The association of sodium caseinate and lecithin seems to be promising to mask the bitterness of acetaminophen. A good agreement between release study and electronic tongue analysis was established.     

Immunohistochemical COX-2 overexpression correlates with HER-2/neu overexpression in invasive breast carcinomas: a pilot study

Cyclooxygenase-2 (COX-2) is a prostaglandin synthase that catalyzes the synthesis of prostaglandin G2 and H2. It has been shown that COX-2 plays an important role in tumorigenesis of different tumor types and it is thought to take part in breast carcinogenesis. In the present study, we aimed to investigate the relationship of immunohistochemical COX-2 expression with clinicopathological parameters, including HER-2/neu overexpression in invasive breast carcinoma (IBC).Our study population comprised 10 normal breasts, 25 ductal carcinomas in situ (DCIS), and 51 invasive breast carcinomas. Immunohistochemical overexpressions of COX-2 and HER-2/neu were investigated in sections of formalin-fixed, paraffin-embedded blocks by 3 observers.In normal breast, DCIS and IBC, the COX-2 overexpression rate was 0%, 84%, and 58.8%, respectively. In IBC, COX-2 overexpression had a significant relationship with HER-2/neu overexpression (p = 0.026) and a high histological grade (p = 0.026). COX-2 expression in both DCIS (n = 25) and IBC (n = 51) was significantly higher than in normal breast tissue (p < 0.0001). In addition, the COX-2 expression rate was significantly higher in DCIS than in IBC (p = 0.042).Our results indicated that COX-2 overexpression correlates with aggressive phenotypic features, such as HER-2/neu overexpression and high histological grade in IBC. Increased expression of COX-2 in both DCIS and IBC in comparison to normal breast could indicate a role in breast carcinogenesis. COX-2 overexpression may provide a clinically useful biomarker for estimating tumor aggressiveness.     

The XXXIV Spanish Congress of Pediatric Nephrology 4-7 June 2008, Sevilla, Spain

Abstracts

The XXXIV Spanish Congress of Pediatric Nephrology 4-7 June 2008, Sevilla, Spain