Formation of functional nanobiocatalysts with a novel and encouraging immobilization approach and their versatile bioanalytical applications

The discovery of functional organic–inorganic hybrid nanoflowers (FNFs) consisting of proteins/enzymes as the organic components and Cu(ii) ion as the inorganic component has made an enormous impact on enzyme immobilization studies. The FNFs synthesized by an encouraging and novel approach not only showed high stabilities but also much enhanced catalytic activities as compared to free and conventionally immobilized enzymes. A recent development demonstrated that FNF formation has moved beyond the initial discovery in which enzymes and Cu²⁺ ions used as the organic and inorganic parts, respectively, are replaced with new organic (chitosan, amino acid and plant extracts) and inorganic (Cu²⁺ and Fe²⁺) materials. The new organic materials incorporated into FNFs act as Fenton-like agents and then show peroxidase-like activity owing to the metal ions and the porous structure of FNFs in the presence of hydrogen peroxide (H₂O₂). All FNFs have been widely utilized in many different scientific and industrial fields due to their greatly enhanced activities and stabilities. This review focuses primarily on the preparation, characterization, and bioanalytical applications of FNFs and explains the mechanisms of their formation and enhanced activities and stabilities.

The discovery of functional organic–inorganic hybrid nanoflowers (FNFs) consisting of proteins/enzymes as the organic components and Cu(ii) ion as the inorganic component has made an enormous impact on enzyme immobilization studies.     

Reduced Coronary Flow Reserve and Early Diastolic Filling Abnormalities in Patients with Nephrotic Syndrome

Background. Increased cardiovascular disease risk is very well known in nephrotic syndrome. Coronary flow reserve measurement by trans-thoracic echocardiography reflects coronary microvascular and endothelial function. However, diastolic filling abnormalities by echocardiography may indicate diastolic dysfunction. Our aim was to evaluate endothelial and diastolic functions by trans-thoracic echocardiography in nephrotic syndrome. Methods. Eighteen patients with nephrotic syndrome (five females, 34 ± 17 years) and 30 controls (10 females, 35 ± 10 years) were evaluated in this cross-sectional observational study. Age, weight, lipid profile, glucose, blood urea nitrogen, creatinine, serum albumin, total protein, C-reactive protein, erythrocyte sedimentation rate, blood pressures, 24-hour urine volume, and protein were recorded. Glomerular filtration rate was estimated by Cockcroft-Gault Formula. Doppler flow and other echocardiographic parameters were measured by Vivid 7 echocardiography. Results. Coronary flow reserve was significantly lower in patients than controls (p < 0.001) and was negatively correlated with proteinuria (p < 0. 001), creatinine levels (p?=?0.03), total cholesterol (p?=?0.02), C-reactive protein (p?=?0.02), and erythrocyte sedimentation rate (p?=?0.005). E/A ratio was significantly lower in patients than in controls (p?=?0.005). DT was significantly higher in patients than in controls (p?=?0.01) and isovolumic relaxation time was similar in both groups. Conclusion. Coronary flow reserve and left ventricular diastolic filling are significantly impaired in nephrotic syndrome. Proteinuria, serum creatinine, total cholesterol and inflammation may have all contributory effects on endothelial dysfunction. Early evaluation of patients with nephrotic syndrome should include coronary flow and diastolic function by echocardiography.     

Expression analysis and clinical correlation of aquaporin 1 and 4 genes in human hippocampal sclerosis

Mesial temporal sclerosis (MTS) is the most frequent cause of drug resistant symptomatic partial epilepsy. The mechanism and genetic background of this unique pathology are not well understood. Aquaporins (AQP) are regulators of water homeostasis in the brain and are expressed in the human hippocampus. We explored the role of AQP genes in the pathogenetic mechanisms of MTS through an evaluation of gene expression in surgically removed human brain tissue. We analyzed AQP1 and 4 mRNA levels by quantitative real-time polymerase chain reaction and normalized to ABL and cyclophilin genes, followed by immunohistochemistry for AQP4. Relative expressions were calculated according to the delta Ct method and the results were compared using the Mann-Whitney U test. Brain specimens of 23 patients with epilepsy who had undergone surgery for MTS and seven control autopsy specimens were investigated. Clinical findings were concordant with previous studies and 61% of the patients were seizure-free in the postoperative period. AQP1 and 4 gene expression levels did not differ between MTS patients and control groups. Immunofluorescence analysis of AQP4 supported the expression results, showing no difference. Previous studies have reported contradictory results about the expression levels of AQP in MTS. To our knowledge, only one study has suggested upregulation whereas the other indicated downregulation of perivascular AQP4. Our study did not support these findings and may rule out the involvement of AQP in human MTS.     

Increased serum renalase in hemodialysis patients: is it related to left ventricular hypertrophy?

Introduction: Left ventricular hypertrophy (LVH) is one of the most common cardiac abnormalities in patients with end stage renal disease (ESRD). Hypertension, diabetes, increased body mass index, gender, age, anemia, and hyperparathyroidism have been described as risk factors for LVH in patients on dialysis. However, there may be other risk factors which have not been described yet. Recent studies show that renalase is associated with cardiovascular events. The aim of this study was to reveal the relation between renalase, LVH in patients under hemodialysis (HD) treatment.

Methods: The study included 50?HD patients and 35 healthy controls. Serum renalase levels and left ventricle mass index (LVMI) were measured in all participants and the relation between these variables was examined.

Findings: LVMI was positively correlated with dialysis vintage and C-reactive protein (CRP) (r?=?0.387, p?=?0.005 and r?=?0.597, p?r?=??0.324, p?=?0.022 and r?=??0.499, p?r?=?0.263, p?=?0.065). Serum renalase levels were significantly higher in HD patients (212?±?127?ng/mL) compared to controls (116?±?67?ng/mL) (p?r?=?0.677, p?r?=?0.625, p?Discussion: In our study, LVMI was correlated with dialysis vintage, residual diuresis, CRP, and hemoglobin. LVMI tends to correlate with renalase and this correlation may be significant in studies with more patient numbers. The main parameters affecting renalase levels are dialysis vintage and serum creatinine.     

Prolonged QT Dispersion in the Infants of Diabetic Mothers

Myocardial hypertrophy and cardiac dysfunction frequently occur in newborns of diabetic mothers. The authors hypothesized that wall hypertrophy or disproportionate left ventricular wall thickness in newborns of diabetic mothers may affect both QT and QTc dispersion. This study aimed to assess whether left ventricular hypertrophy affects the QT variables of infants born to diabetic mothers. This prospective cross-sectional study was conducted with 47 consecutively selected neonates of gestational diabetic mothers and 30 healthy neonates born to healthy mothers. All the subjects were evaluated during the neonatal period. Electrocardiography with echocardiography was performed for the patients and the control subjects. The newborns of the diabetic mothers were classified according to septal thickness as group 1 (16 newborns with septal hypertrophy) or group 2 (31 newborns without septal hypertrophy). The study group consisted of three cohorts: groups 1, 2, and 3 (control group). Both QT and QTc dispersion were computed from a randomly selected beat as well as from an average beat derived from 12 beats included in a 10-s electrocardiography. A total of 16 infants (34 %) had a septal thickness of 6 mm or greater. The left ventricular end-systolic diameter in group 1 was smaller (p = 0.0029) than in groups 2 and 3 (p = 0.003). The interventricular septal thickness at end diastole (IVSTd) and the left ventricular posterior wall thickness at end diastole in group 1 were higher than in of groups 2 and 3. The QT and QTc dispersion intervals were longer in group 1 than in groups 2 and 3 (p < 0.001), and a highly significant positive correlation was detected between IVSTd and QT dispersion (r = 0.514, p = 0.042). Elevated QT and QTc dispersions may be risk factors for the development of arrhythmias in newborns of diabetic mothers. These patients may critically need systematic cardiac screening.     

Recommendations for Hepatitis B Immunoglobulin and Antiviral Prophylaxis Against Hepatitis B Recurrence After Liver Transplantation

The combination of hepatitis B immunoglobulin and potent nucleos(t)ide analogs after liver transplantation is considered as the standard of care for prophylaxis against hepatitis B virus recurrence. However, the recommended doses, route of administration, and duration of HBIG administration remain unclear. Moreover, hepatitis B immunoglobulin-free prophylaxis with potent nucleos(t)ide analogs has shown promising disease outcomes in preventing hepatitis B virus recurrence. The current recommendations, produced by the Turkish Association for the Study of the Liver, Acute Liver Failure and Liver Transplantation Special Interest Group, suggest a reduced need for hepatitis B immunoglobulin administration with effective long-term suppression of hepatitis B virus replication using potent nucleos(t)ide analogs after liver transplantation.     

Thyroid hormones mediated effect of insulin on alloxan diabetic rat atria

1. The influence of alloxan-induced diabetes was studied on spontaneously beating rat atria. Diabetic atria were found to have decreased rates, increased contractility and decreased responsiveness to both inotropic and chronotropic effects of isoprenaline. 2. Thyroid hormone levels were significantly reduced in diabetic animals. This revealed that the decrease in atrial beta-adrenergic responses was associated with a reduction in serum levels of thyroid hormones. 3. Insulin treatment of diabetic rats for 10 days corrected the changes observed in diabetic atria. Serum levels of thyroid hormones returned to normal following insulin treatment as well. 4. Administration of insulin to thyroidectomized-diabetic rats did not reverse the diabetes-induced changes suggesting that thyroid hormones are needed for insulin to normalize the alterations observed in diabetic atria.     

Effects of anti-oxidant treatment on sciatic nerve dysfunction in streptozotocin-diabetic rats; comparison with essential fatty acids

Summary In Study 1, the effects of treatment of streptozotocin-diabetic rats with the antioxidants, probucol or vitamin E were compared. Untreated diabetic rats showed a reduction of 45% (p<0.01) in nerve laser Doppler flux, which was used as an index of nerve blood flow. In diabetic rats treated with either probucol or vitamin E nerve Doppler flux was reduced by only 13 or 16%, respectively (p<0.01 for either compared to untreated diabetic rats). A second study examined the effects of treatment with evening primrose oil either alone or in combination with probucol. Reduced nerve Doppler flux was reproduced in untreated diabetic rats (47%; p<0.01). In parallel diabetic groups, nerve Doppler flux was reduced by only 14% with evening primrose oil alone and by 8% with evening primrose oil plus probucol (both p<0.01 vs untreated diabetic rats). Both treatments were also associated with marked attenuation of motor and sensory nerve conduction velocity deficits. Measurements on plasma from rats showed normalisation of triglyceride levels by probucol treatment without an effect on those of cholesterol in Study 1. In Study 2, the converse was true for evening primrose oil treatment, whilst the combined treatment lowered both plasma triglycerides and cholesterol. This work indicates similar effects of antioxidants and evening primrose oil against reduced nerve Doppler flux and conduction velocity in diabetic rats, with dissimilar actions on plasma triglycerides and cholesterol.Abbreviations STZ streptozotocin