Contribution to Understanding of Synergy between Red Mud and Common Supplementary Cementitious Materials

Recently, much attention has been paid to the reuse of bauxite residues from alumina production, also known as red mud, in the cement industry. Red mud bears the potential to improve concrete properties due to its favourable chemical composition and particle size. In this work, the synergy between locally available red mud and common supplementary cementitious materials such as fly ash, slag, calcined clay and limestone in cement mixes is investigated. All materials used were sourced from the immediate vicinity of the cement plant. The study of synergy involved the evaluation of the individual chemical reactivity of each material using the R3 test by isothermal calorimetry as well as their joint contribution to the heat of hydration and the composition of the reaction products of the paste and the compressive strength of the mortar. The results show how, by understanding the synergy between the materials, a higher level of cement substitutions can be achieved without compromising the mechanical properties of the mortar.     

Macrolide resistance determinants of group A streptococci in Ankara,Turkey

OBJECTIVES: Macrolide-lincosamide-streptogramin B (MLSB) resistance determinants of group A streptococci (GAS) in Ankara, Turkey, were defined for the first time. ISOLATES AND METHODS: A total of 1355 GAS isolates, collected from three different regions of Ankara, were screened for erythromycin resistance. Resistance phenotypes were determined by a triple-disc test, and the gene determinants responsible were determined by PCR. MICs of erythromycin, clindamycin and spiramycin were measured for the resistant isolates, and susceptibility rates to some further antibiotics were determined. RESULTS: Thirty-six isolates (2.6%) were resistant to erythromycin. Of these, 17 (47.2%) expressed macrolide-restricted resistance (M phenotype), while the remainder expressed inducible (16 isolates, 44.4%) or constitutive (three isolates, 8.3%) MLSB resistance. All isolates of the M phenotype harboured the mef(A) gene. Of non-M isolates, 14 harboured erm(A) subclass erm(TR) and five had erm(B) genes. There was a significant relationship between tetracycline resistance and the inducible phenotype (P < 0.05). Macrolide resistance was significantly higher in adults (P < 0.05), and increased more than two-fold in 2002 compared with 2001 (P < 0.05). CONCLUSION: The prevalence of macrolide resistance in GAS is low in Ankara; therefore, routine antimicrobial susceptibility testing against these agents seems unwarranted.     

Thrombin activatable fibrinolysis inhibitor in Behçet's disease

INTRODUCTION: Thrombin activatable fibrinolysis inhibitor (TAFI) is a procarboxypeptidase downregulating plasmin formation, thereby causing a tendency for thrombosis development. Since, Beh?et's disease (BD) is a systemic vasculitis, which is commonly complicated by arterial and venous thrombosis, we aimed to find out plasma TAFI levels in BD, compared with healthy controls. We also searched whether plasma TAFI levels were significantly different between Beh?et's subgroups with and without thrombosis. MATERIALS AND METHODS: In this study, 105 BD patients (M/F: 64/41; mean age 36+/-1 years), followed up by Ege University Rheumatology Department were enrolled. The exclusion criteria were hemophilia, hyperlipidemia, diabetes mellitus, hepatic diseases renal failure, antiphospholipid positivity, oral contraceptive use and pregnancy. Age-and sex-matched healthy controls (n=53) were also included. Plasma TAFI levels were measured by ELISA. Since TAFI is also an acute-phase reactant, we also measured other inflammatory markers such as C-reactive protein (CRP). RESULTS: Plasma TAFI levels were significantly higher in Beh?et's patients (91.1+/-7.4 ng/ml) compared with healthy controls (14.3+/-4.5 ng/ml) (P<0.001), but there were no significant difference between the subgroups with and without thrombosis. In BD, there was no correlation between plasma TAFI levels and CRP. CONCLUSIONS: Regardless of manifest thrombosis, plasma TAFI levels in BD were significantly higher than in healthy controls. High TAFI levels might possibly contribute to the thrombotic tendency in BD. Future studies investigating TAFI gene polymorphism and functional activity are clearly needed, to clarify the exact role of TAFI in Beh?et's thrombosis.     

Magnetic Resonance Spectroscopy of the Thalamus in Essential Tremor Patients

BACKGROUND AND PURPOSE: Although essential tremor (ET) is one of the most common movement disorders, its pathogenesis remains obscure. The ventral intermediate nucleus of the thalamus (VIM nucleus) is suggested to play an important role in the occurrence of disease. In this study, the authors investigated the presence of biochemical or metabolic alterations in the thalamus of patients with ET using magnetic resonance (MR) spectroscopy. METHODS: The study group included 14 patients with ET who suffered from tremor predominantly in their right arm and 9 healthy controls. All patients and controls were right handed. Following conventional cranial MR imaging, single voxel proton MR spectroscopy of the thalamus involving the VIM nuclei was performed bilaterally in both the patients with ET and controls. Metabolite peaks of choline (Cho), creatine (Cr), and Nacetylaspartate (NAA) were obtained from each spectroscopic volume of interest. The right and left thalamic NAA/Cr and Cho/ Cr ratios were compared first within the patient group and then between the control and patient groups. The differences in age and spectroscopic data between groups were assessed using the Mann-Whitney U test, whereas the comparison within groups between left thalamus and right thalamus was done by the Wilcoxon test. RESULTS: In patients with ET, the NAA/Cr ratio of the right thalamus was found to be significantly higher than the NAA/Cr ratio of the left thalamus (P= .02). However, NAA/Cr and Cho/Cr ratios were found to be similar (P> .05) when we compared the control and patient groups for the right thalamus and then the left thalamus. CONCLUSION: These data present preliminary evidence for metabolic alterations of the contralateral thalamus (namely, low NAA/Cr ratio) in ET patients with predominantly involved right arm. However, the series is small and further data are necessary to clear the subject adequately.     

Effect of melatonin in the prevention of post-operative adhesion formation in a rat uterine horn adhesion model

BACKGROUND: Our main aim was to investigate the effects of melatonin (ME), possibly the most powerful free-radical scavenger, on the prevention of i.p. adhesion formation in rat uterine horn. Our secondary aim was to determine whether different methods of administration of ME were beneficial. METHODS: Animals were randomly assigned into seven groups, each consisting of 13 rats. Measured serosal injury was created using a standard technique. While control and two sham groups were not given ME, two of the remaining four groups were given a single dose of 10 mg/kg (2 mg) of ME i.p. immediately after injury and 30 min prior to injury respectively. In the two other groups, ME treatment was continued daily for 5 days. All animals were killed 2 weeks after surgery and adhesions were determined and scored by a examiner blinded to the test. RESULTS: The extent, severity and total scores of adhesion were found to be significantly reduced in all of the ME treatment groups when compared with control and sham groups. There were no statistically significant differences between the treatment groups. CONCLUSIONS: This study showed that even single dose ME therapy was effective in the prevention of post- operative i.p. adhesion formation.     

Desflurane anaesthesia in a patient with multiple sclerosis in total hip replacement

Multiple sclerosis (MS) is a progressive demyelinating disease presenting with a relapsing-remitting course and affects large areas of the brain and the spinal cord. Surgical stress often induces exacerbation of MS symptoms. It is mandatory to prepare the MS patient very carefully for the surgery and anaesthesia with an effective premedication and an effective postoperative analgesia following a safe and minimal-risk anaesthesia management. In recent reports, results of general and regional anaesthesia in MS patients have been discussed. To our knowledge this is the first case report of the use of desflurane anaesthesia in a patient with MS. In conclusion, desflurane anaesthesia is a safe and useful method for MS patients.