Modified gold surfaces by 6-(ferrocenyl)hexanethiol/dendrimer/gold nanoparticles as a platform for the mediated biosensing applications

An electrochemical biosensor mediated by using 6-(Ferrocenyl) hexanethiol (FcSH) was fabricated by construction of gold nanoparticles (AuNPs) on the surface of polyamidoamine dendrimer (PAMAM) modified gold electrode. Glucose oxidase (GOx) was used as a model enzyme and was immobilized onto the gold surface forming a self assembled monolayer via FcSH and cysteamine. Cyclic voltammetry and amperometry were used for the characterization of electrochemical response towards glucose substrate. Following the optimization of medium pH, enzyme loading, AuNP and FcSH amount, the linear range for the glucose was studied and found as 1.0 to 5.0mM with the detection limit (LOD) of 0.6mM according to S/N=3. Finally, the proposed Au/AuNP/(FcSH+Cyst)/PAMAM/GOx biosensor was successfully applied for the glucose analysis in beverages, and the results were compared with those obtained by HPLC.

Ocular biometry characteristics and its relationship with age, gender, spherical equivalent in Turkish children

Background

Studying ocular biometric parameters in different populations and determining the relationship with personal characteristics can provide valuable information about ocular growth and help provide a better understanding of refractive errors.

Aims

To describe distributions of ocular biometry and to evaluate its associations with age, gender, spheric equivalent in Turkish children.

Patients and Methods

In this prospective study 344 children aged 3-14 years were evaluated. Parameters studied included axial length (AL), anterior chamber depth (ACD), and mean corneal radius (CR) measured with optical biometry. Cycloplegic refraction values were obtained using autorefractometer. The change of biometric parameters according to age and gender were evaluated. The relationship between ocular biometry parameters with refraction and age was analyzed by linear regression.

Results

Mean spherical equivalent (SE), AL, ACD and AL/CR observed to be lowest in the preschooler group (P < 0.001). SE reduced with age, and a weak correlation observed between SE and age (r = -0.333). AL and ACD had moderate and weak positive correlations with age respectively (r = 0.511; r = 0.304). There were negative correlations between SE with AL, ACD and AL/CR (r = -0.826; r = -0.540; r = -0.886). The strongest correlation with SE among these parameters was identified for AL/CR. AL and ACD were higher in boys, while the CR was lower in girls (p < 0.001).

Conclusion

While AL in children in late schooler group is higher than European countries, it shows similar characteristics in early schooler group. In addition AL is lower in all age groups than Asian population sexcept preschooler group. With age AL increases, SE decreases and AL plays a key role in refractive development.

Physicochemical determinants of antibody-protein interactions

Antibodies are specialized proteins generated by immune system for high specificity and affinity binding to target antigens. Because of their essential roles in immune system, antibodies have been successfully developed and engineered as biopharmaceuticals for treatment of various diseases. Analysis of antibody-protein interactions is always required to get detailed information on effectivity of such antibody-based therapeutics. Although physicochemical rules cannot be generalized for every antibody-protein interaction, there are some features which should be taken into account during antibody development and engineering efforts. In this chapter, physicochemical analysis of antibody paratope-protein epitope interactions will be discussed to highlight important characteristics. First, paratope and non-paratope regions of antibodies will be described and important roles of these regions on binding and biophysical features of antibodies will be discussed. Then, general features of epitope regions of protein antigens will be introduced along with several computational/experimental tools to identify them. Lastly, a rising star of antibody biopharmaceuticals, nanobodies, will be described to show importance of next-generation antibody fragment based biopharmaceuticals in drug development.

Soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) is decreased in lung cancer patients showing progression: a pilot study

Tumor growth and metastasis depend on angiogenesis, and the vascular endothelial growth factor (VEGF) is known to be one of the most important angiogenic factors although the knowledge about its receptors is limited. We, therefore, investigated the treatment-related changes both in the level of the soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) in the serum by ELISA and the expression of VEGFR-1 in cancer tissues by immunohistochemistry. The serum levels were studied in 38 lung cancer patients, and 55 control subjects (21 benign disease and 34 healthy subjects) before the chemotherapy. The treatment-related changes in serum sVEGFR-1 were evaluated in 15 patients 24 and 48 hours after treatment. In addition to serum analysis, the tissue expressions were evaluated in 32 patients before treatment. The treatment-related changes in tissue VEGFR-1 expressions were evaluated in only 12 patients 24 hours after treatment. We observed no significant difference in terms of serum sVEGFR-1 levels between malignant and nonmalignant groups (p > 0.05). There were no significant differences in the levels of sVEGFR-1 before and after treatment (p > 0.05). However, there was a significant difference between sVEGFR-1 levels in the groups (regressive, stable, progressive) classified according to the response to therapy (p = 0.043). A significant difference also was present between the expression levels of tissue VEGFR-1 in the same groups (p = 0.037). As a conclusion, we suggest that prechemotherapy sVEGFR-1 can be helpful for prediction of long-term response to therapy, but it should be studied in larger groups to elucidate its benefit in clinics.

Neutrophil-to-lymphocyte ratio in obstructive sleep apnea; a multi center, retrospective study

OBJECTIVE

Systemic inflammation is important in pathophysiology of obstructive sleep apnea (OSA) and its comorbidity. Neutrophil to lymphocyte ratio (N/L ratio) is a novel inflammation index that has been shown to independently predict poor clinical outcomes. In this study, we aimed to evaluate the role of N/L ratio in OSA patients and comparing with other well-known inflammatory marker, C-reactive protein (CRP).

PATIENTS AND METHODS

We conducted a retrospective analysis of 481 patients with mild, moderate and severe OSA (163,158 and 160 patients, respectively) and leukocyte profiles of 80 sex-, age- and body mass index- matched healthy controls. Patients were excluded if they had underlying cancer, chronic inflammatory disease, any systemic infection, uncontrolled hypertension and diabetes mellitus, a known acute coronary syndrome, valvular heart disease, a known thyroid, renal or hepatic dysfunction.

RESULTS

We found that N/L Ratio in severe OSA patients was significantly higher compared with mild, moderate, OSA patients and healthy controls (p < 0.001). However, there was no difference between mild and moderate OSA patients (p = 0.636). There was also no significant difference between mild-moderate OSA patients and healthy groups (p = 0.150). CRP levels were not different in all OSA stages (p = 0.595). By Spearman correlation, there was no correlation between CRP and N/L ratio.

CONCLUSIONS

N/L ratio, which is quick, cheap, easily measurable novel inflammatory marker with routine complete blood count analysis, is a surrogate marker of obstructive sleep apnea severity.

Comparison of the protective effects of selective endothelin-a receptor antagonist, ambrisentan, and dual endothelin-A/B receptor antagonist, bosentan, in experimental renal ischemia reperfusion injury

AIM

This study aims to compare the protective effects of ambrisentan, a selective endothelin typeA receptor antagonist, and bosentan, a dual endothelin typeA/B receptor antagonist, on experimental renal ischemia reperfusion injury.

METHOD

The study sample consisted of 21 female rats, which were divided into 3 groups: Control, Ambrisentan and Bosentan. For the ischemia-reperfusion injury model, left‑kidney nephrectomy was performed after sacrificing the animals. In the immunohistochemical examination, caspase-3 was examined, and then the apoptotic index was determined. In the biochemical examination, the activities of malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase, and the levels of nitrite (NOx), TNF-α, and IL-1β were determined.

RESULTS

There were statistically significant differences between the groups in terms of total injury score grade in range of 0‒3 (p=0.001).The glomerular and tubular apoptotic indices were higher in the control group as compared to those of the ambrisentan and bosentan groups (p=0.001).There were no statistically significant differences in terms of SOD, CAT, GPx, MDA, IL-1β and TNF-α measurements among the groups (p>0.05).

CONCLUSIONS

In the experimentally created renal ischemia reperfusion model, both ambrisentan and bosentan increased the NOx level, decreased the apoptosis, and protected the kidney from renal ischemia reperfusion injury. However, no significant superiority was found between ambrisentan and bosentan in terms of their protective effects (Tab. 3, Fig. 2, Ref. 31).

Deep learning-based design and experimental validation of a medicine-like human antibody library

Antibody generation requires the use of one or more time-consuming methods, namely animal immunization, and in vitro display technologies. However, the recent availability of large amounts of antibody sequence and structural data in the public domain along with the advent of generative deep learning algorithms raises the possibility of computationally generating novel antibody sequences with desirable developability attributes. Here, we describe a deep learning model for computationally generating libraries of highly human antibody variable regions whose intrinsic physicochemical properties resemble those of the variable regions of the marketed antibody-based biotherapeutics (medicine-likeness). We generated 100000 variable region sequences of antigen-agnostic human antibodies belonging to the IGHV3-IGKV1 germline pair using a training dataset of 31416 human antibodies that satisfied our computational developability criteria. The in-silico generated antibodies recapitulate intrinsic sequence, structural, and physicochemical properties of the training antibodies, and compare favorably with the experimentally measured biophysical attributes of 100 variable regions of marketed and clinical stage antibody-based biotherapeutics. A sample of 51 highly diverse in-silico generated antibodies with >90th percentile medicine-likeness and > 90% humanness was evaluated by two independent experimental laboratories. Our data show the in-silico generated sequences exhibit high expression, monomer content, and thermal stability along with low hydrophobicity, self-association, and non-specific binding when produced as full-length monoclonal antibodies. The ability to computationally generate developable human antibody libraries is a first step towards enabling in-silico discovery of antibody-based biotherapeutics. These findings are expected to accelerate in-silico discovery of antibody-based biotherapeutics and expand the druggable antigen space to include targets refractory to conventional antibody discovery methods requiring in vitro antigen production.