Effects of particle size, extraction time and temperature, and derivatization time on determination of theanine in tea

Theanine is a unique amino acid almost exclusively found in tea which is considered to have positive effects on human health. Data on theanine methods of analysis are quite rare in the literature and extraction parameters are not well documented. In this study, optimum extraction parameters such as particle size, extraction temperature and time, and derivatization time with coloring reagent were determined. High performance liquid chromatography (HPLC) with fluorescence detector was used for the determination of theanine, and chromatographic separations were achieved by using reverse-phase C₁₈ column. HPLC gradient program was improved to get better resolution of theanine. Linearity, selectivity, limit of detection (LOD), limit of quantification (LOQ) and precision of method (intra and inter-day) were also determined. Best extraction conditions for particle size, extraction temperature, extraction time and derivatization time were found to be 150–300 μm, 80 °C, 25 min and 2 min, respectively. Precision of the HPLC method was very high since intra-day and inter-day variations were 1.14% and 0.96%, respectively. LOD and LOQ values were found as 20 ng/mL and 50 ng/mL indicating the method is highly sensitive.     

Assessment of the Anterior Talofibular Ligament Thickness in Patients with Chronic Stroke: An Ultrasonographic Study

Background

Patients with equinovarus deformity have an increased risk of fall and ankle ligament injury, because of inappropriate prepositioning of the ankle at the end of the swing phase, and inadequate leg and ankle stability during the stance phase. Accordingly, the aim of this study is to compare anterior talofibular ligament (ATFL) thickness of chronic stroke patients with that of healthy individuals using ultrasonography.

Local cold effect on the excitability recovery curve of the sympathetic skin response

The sympathetic skin response (SSR) is an established technique used to assess the activity of the sympathetic sudomotor pathway, but it is limited in application by the habituation process. The nature of habituation is not clear. In this study we aimed to further understand the role of the peripheral mechanism in the habituation of the SSR. We recorded SSRs to paired stimuli with interstimulus intervals of 1, 2, 3, 4 and 5 seconds on both hands of 15 volunteers simultaneously, while the right hand was cooled to 23-24 degrees C and the left hand was between 32 and 33 degrees C. The amplitude and latency generated by the first stimulus (SSR1) and the second stimulus (SSR2) were measured. While SSR2 first occurred at ISI 2 in 7 subjects and ISI 3 in 8 subjects on the normal side, SSR2 first occurred at ISI 4 in 7 subjects and ISI 3 in 8 subjects on the cooled side. The SSR amplitude recovery percentage, which was obtained by dividing the amplitude of SSR2 by the amplitude of SSR1, was significantly different on the cooled side. No significant differences were found between SSR1 and SSR2 latencies, which were measured at ISI 3, 4 and 5 on the normal side and at ISI 5 on the cooled side. Our findings further support that a peripheral component might be involved in the modification and habituation of the SSR in terms of amplitude, but not of latency.     

Early and midterm results of complex cerebral aneurysms treated with Silk stent

Introduction

Endovascular treatment of intracranial aneurysms has been an effective treatment option. In this paper, we report our experience with the Silk stent (SS) for endovascular treatment of complex intracranial aneurysms and present periprocedural events, immediate results, delayed complications, and imaging and clinical follow-up results.

Methods

We retrospectively examined angiographic images and clinical reports of 76 consecutive patients with 87 intracranial aneurysms who were treated with SSs between March 2008 and June 2011.

Results

All aneurysms could be successfully covered technically using implanted SSs, with an overall mortality of 6.6?%. Two transient morbidities (2.6?%) and three permanent morbidities due to embolic events (3.9?%) were observed. Unexpected procedural technical events occurred in 18 procedures (18/78, 23.1?%). Control angiographies were performed in all 71 patients with 82 aneurysms (100?%). Mean angiographic follow-up time was 17.5?±?11.1?months [range 2?C48?months]. Sixteen of the 71 patients with 19 aneurysms had only early angiographic controls in the first 6?months while remaining 55 patients with 63 aneurysms (77.5?%) had late controls after 6?months. Overall control angiographic occlusion rates were as follows: 87.8?% (72/82) total occlusion, 8.5?% residual aneurysm filling, and 3.7?% residual neck filling. The general in-stent stenosis rate in controls was 5.6?% and the stented parent artery occlusion rate was 4.2?%. Five (6.6?%) aneurysms ruptured after stent implantation in our series.

Conclusion

The Silk stent is an effective tool for the treatment of challenging aneurysms, which have previously demonstrated higher re-growth rates and technical problems, despite unexpected higher hemorrhage rates after treatment and deployment difficulties.     

Role of apparent diffusion coefficient values and diffusion-weighted magnetic resonance imaging in differentiation between benign and malignant thyroid nodules

ObjectiveThe purpose of the study was to differentiate between benign and malignant thyroid nodules using nodule-spinal cord signal intensity and nodule apparent diffusion coefficient (ADC) ratios on diffusion-weighted magnetic resonance imaging (DW-MRI).Materials and MethodsForty-four patients (27 females, 17 males; mean age, 49 years) with nodules who underwent DW-MRI were included in this study. The images were acquired with 0, 50, 400 and 1000 s/mm² b values. ADC maps were calculated afterwards. Fine needle aspiration biopsies (FNAB) were performed at the same day with DW-MRI acquisition. The diagnosis in patients where malignity was detected after FNAB was confirmed by histopathologic analysis of the operation material. The signal intensities of the spinal cord and the nodule were measured additionally, over b-1000 diffusion-weighted images. Nodule/cord signal intensity (SI) ratios were obtained and the digital values were calculated by dividing to ADC values estimated for each nodule. Statistical analysis was performed.ResultsThe (nodule SI-cord SI)/nodule ADC ratio is calculated in the DW images, and a statistically significant relationship was found between this ratio and the histopathology of the nodules (P<.001). The ratio was determined as 0.27 in benign and 0.86 in malignant lesions. The result of receiver operating characteristic (ROC) analysis was statistically significant, and the area under curve (100%) was considerably high. The threshold value was calculated as 0.56 according to the ROC analysis. According to this threshold value, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy rates for (nodule SI/cord SI)/ADC ratios in differentiating benign from malignant thyroid nodules are calculated as 100%, 97%, 83%, 100%, and 98%, respectively.ConclusionWe have found that (nodule/cord SI)/nodule ADC ratio has the highest values for sensitivity and specificity among the tests defined for characterization of nodules.     

The prevalence of metabolic syndrome is increased in patients with anti-neutrophil cytoplasmic antibody-associated vasculitis

Purpose

Cardiovascular disease is one of the major causes of mortality in anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV). Metabolic syndrome (MetS) is associated with increased cardiovascular risk in the normal population. However, MetS in AAV has not been adequately investigated. We aimed to determine MetS prevalence and associated factors in AAV patients.

Methods

Thirty-seven AAV patients and 42 healthy controls were enrolled. MetS was determined by International Diabetes Federation (IDF) and National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATPIII) criteria. The relationship between clinical features of AAV and MetS was also investigated.

Results

MetS was significantly higher in AAV patients than controls by NCEP-ATPIII (51.4% vs. 26.2%, p 0.022) and IDF (62.2% vs. 35.7%, p 0.020). When AAV patients with MetS were compared to those without, there were significant differences in age, CRP, GFR and NT-pro-BNP. Age [58 (13) vs. 50 (8) years p: 0.028], CRP [4.0 (3.6) vs. 3.2 (1.0) mg/l, p 0.021] and NT-pro-BNP [173.5 (343.7) vs. 106.0 (103.0) pg/ml, p 0.013] were significantly higher in AAV patients with MetS than those without; GFR was significantly lower [38 (46) vs. 83 (51) ml/min/1.73 m², p 0.004]. ROC curve analysis showed NT-pro-BNP?>?58.0 ng/ml predicted MetS with 87.1% sensitivity and 46.7% specificity (Area under curve: 0.71, CI 0.536–0.902, p 0.041). Multivariate analysis revealed age [OR (95% CI): 1.180 (1.010–1.370), p 0.039] and NT-pro-BNP?>?58 pg/ml [OR (95% CI): 5.5 (1.02–30.1) p 0.047] were independent predictors of MetS in AAV patients.

Conclusion

MetS is significantly higher in AAV patients than controls and is associated with age and NT-pro-BNP. Screening and treating MetS may improve prognosis in AAV patients.

     

Guillain-Barré syndrome during treatment with interferon alpha for hepatitis B.

We describe a patient who developed acute demyelinating polyneuropathy on the sixth week of interferon (IFN)alpha therapy for chronic hepatitis B (HBV) infection. A 23-year-old man with chronic HBV infection had acute onset of demyelinating polyneuropathy shortly after completing a standard 6-week course of therapy with IFNalpha 2a. Clinical findings, electrodiagnostic studies and elevated cerebrospinal fluid protein levels without cells supported the diagnosis of Guillain-Barré syndrome (GBS). Other potential causes of GBS were ruled out. It remains unknown whether IFNalpha or the HBV infection itself was the cause of GBS, but it is evident that IFNalpha could not have prevented the development of GBS in our patient. We suggest that coexistent HBV infection and IFNalpha therapy may play a role in triggering an autoimmune response to peripheral nerve myelin.     

Dietary whey supplementation in experimental models of wound healing

Whey is a dairy product containing milk serum proteins with diverse biological effects. In this study, the effect of dietary whey supplementation on wound healing was investigated. Rats were fed a standard or whey-supplemented diet for three weeks. Wound healing parameters, glutathione, and lipid peroxide levels were determined three days after the application of two different models of wound healing, i.e. laparotomy and colonic anastomosis. Dietary whey supplementation significantly increased glutathione levels and suppressed lipid peroxidation after experimental laparotomy and colonic anastomosis. Bursting pressures, hydroxyproline, and cytokine levels were not changed. Our results show that dietary whey supplementation increases glutathione synthesis and cellular antioxidant defense. Long-term effects of whey feeding on wound healing remains to be investigated.     

Effects of ACE inhibition and angiotensin II receptor blockade on glomerular basement membrane protein excretion and charge selectivity in type 2 diabetic patients.

Angiotensin-converting enzyme (ACE) inhibitors may reduce urinary albumin excretion (UAE) by decreasing glomerular pressure and increasing glomerular charge selectivity through preservation of glycosaminoglycans. The effect of Angiotensin II antagonism on glomerular charge selectivity remains to be determined. The aim of this study was to compare the effects of an AT1 blocker losartan and an ACE inhibitor (ACE-I) enalapril on UAE, extracellular matrix proteins, glycosaminoglycan excretion (UGAG) and red blood cell anionic charge (RBCCh) which are the indirect markers of glomerular basement membrane anionic content in hypertensive Type 2 diabetic patients. Twenty-four patients were randomised into two groups and received either enalapril (520 mg/d) or losartan (50100 mg/d). All parameters were measured at baseline and after six months of treatment. At the end of six months, systolic and diastolic blood pressures (BP), UAE rates, UGAG excretion and RBCCh were significantly and equally reduced in both treatment groups compared with baseline. RBCCh was negatively correlated with UAE (r=-0.57, p<0.0001) and UGAG excretion (r=-0.57, p<0.0001); UAE was correlated with UGAG excretion (r=0.58, p<0.0001). In conclusion, enalapril and losartan treatment were equally effective in reducing BP, UAE as well as UGAG excretion and preserving RBCCh in hypertensive Type 2 diabetic patients. ACE inhibition and AT1-receptor blockade may have favourable effects on preserving glomerular anionic content in hypertensive diabetic patients.