Biotin as a structural component in the detection of small model antigens in BLA-S-ELISA

An interesting biotin-linked-antigen-Sandwich-ELISA was developed (BLA-S-ELISA), which based on the captured Trinitrophenol-Biotin (TNP-Biotin) molecule between the immobilised monovalent antibody and enzyme-conjugated streptavidin. Monoclonal anti-Trinitrotoluene single chain fragment antibody (anti-TNT-scFv) was cloned and expressed in E. coli cells, and then used as an immobilised component in an assay. Thereafter, the previously synthesised TNP-Biotin was added as antigen followed by the addition of streptavidin-horseradish peroxidase (streptavidin-HRP) conjugate which led finally to the formation of a three-component system (antibody/TNP-Biotin/streptavidin-HRP). The assay was performed with a range of different dilutions of TNP-Biotin to establish its minimal detectable concentration. The detection limit of TNP-Biotin was 4 ngmL-1 (i.e. 200 pg or 0.42 pmol antigen calculated on the basis of 50 μL sample or 8.4 nM expressed in concentration units). According to our best knowledge, this is the very first time for any model antigen to be detected with such a form of biotin-streptavidin sandwich-assay.

Thermal Characterisation and Isoconversional Kinetic Analysis of Osmotically Dried Pork Meat Proteins Longissimus dorsi

The kinetic properties and thermal characteristics of fresh pork meat proteins (Longissimus dorsi), as well as osmotically dehydrated meat proteins, were investigated using differential scanning calorimetry. Two isoconversional kinetical methods, namely the differential Friedman and integral Ortega methods, were employed to analyze the data. The obtained kinetic triplet, activation energy, pre-exponential factor, and extent of conversion, has been discussed. The resulting activation energy for proteins of fresh meat ranges between 751 kJ·mol-1 for myosin, 152 kJ·mol-1 for collagen and sarcoplasmic proteins, and 331 kJ·mol-1 for actin at a conversion degree of 0.1 to 0.9. For osmotically dried pork meat proteins, the values range from 307 kJ·mol-1 for myosin 272 kJ·mol-1 for collagen and sarcoplasmic proteins, and 334.83 kJ·mol-1 for actin at a conversion degree from 0.1 to 0.9. The proteins of the dry meat obtained by osmotic dehydration in molasses could be described as partly unfolded as they retain the characteristic protein denaturation transition. Concerning the decrease in enthalpies of proteins denaturation, thermodynamic destabilization of dried meat proteins occurred. On the contrary, dried meat proteins were thermally stabilized with respect to increase in the temperatures of denaturation. Knowledge of the nature of meat protein denaturation of each kind of meat product is one of the necessary tools for developing the technology of meat product processing and to achieve desired quality and nutritional value. The kinetic analysis of meat protein denaturation is appropriate because protein denaturation gives rise to changes in meat texture during processing and directly affects the quality of product.

Sensorineural Hearing Loss in a Child with Succinic Semialdehyde Dehydrogenase Deficiency

Succinic semialdehyde dehydrogenase (SSADH) deficiency is a rare autosomal-recessive disorder of gamma-aminobutyric acid (GABA) metabolism, resulting in accumulation of GABA and gamma-hydroxybutyric acid (GHB) in physiological fluids. Approximately 450 patients have been diagnosed worldwide with this inherited neurotransmitter disorder. We report on a five-year-old male patient, homozygous for the pathogenic variant (NM_170740:c.1265G>A) in ALDH5A1 presenting with an unexpected association of typical SSADH deficiency manifestations with bilateral sensorineural hearing loss (SNHL). Brainstem evoked response audiometry (BERA) testing showed mid-frequency sensorineural hearing damage that suggested a hereditary component to SNHL. Whole exome sequencing (WES) failed to discern other genetic causes of deafness. Several variants of uncertain significance (VUS) detected in genes known for their role in hearing physiology could not be verified as the cause for the SNHL. It is known that central auditory processing depends on a delicate balance between excitatory and inhibitory neurotransmission, and GABA is known to play a significant role in this process. Additionally, excessive concentrations of accumulated GABA and GBH are known to cause a down-regulation of GABA receptors, which could have an adverse influence on hearing function. However, these mechanisms are very speculative in context of SNHL in a patient with inherited disorder of GABA metabolism. Injury of the globi pallidi, one of hallmarks of SSADH deficiency, could also be a contributory factor to SNHL, as was suspected in some other inborn errors in metabolism. We hope that this case will contribute to the understanding of phenotypic complexity of SSADH deficiency.

Molecular docking and density functional theory studies on creatine, guanidinoacetic acid, and their phosphorylated analogues binding to muscle creatine kinase

Comparative molecular docking studies on creatine and guanidinoacetic acid, as well as their phosphorylated analogues, creatine phosphate, and phosphorylated guanidinoacetic acid, are investigated. Docking and density functional theory studies are carried out for muscle creatine kinase. The changes in the geometries of the ligands before and after binding to the enzyme are investigated to explain the better binding of guanidinoacetic acid and phosphorylated guanidinoacetic acid compared to creatine and creatine phosphate.

Functionality and Storability of Cookies Fortified at the Industrial Scale with up to 75% of Apple Pomace Flour Produced by Dehydration

Apple pomace flour (APF) with high content of dietary fibers (DF), total polyphenolics (TPCs) and flavonoids (TFCs) was produced at the industrial scale. Bulk and tapped density, swelling, water and oil holding capacity, solubility and hydration density of fine and coarse APF with average particle size 0.16 and 0.50 mm were compared. The effect of wheat flour substitution with 25%, 50% and 75% of fine and coarse APF was studied upon cookies production at the industrial scale and after one year of storage. Coarse APF performed better in respect to sensorial properties, content and retention of dietary compounds and antioxidant (AO) activity. The cookies with optimal share of coarse APF (50%) contained 21 g/100 g of DF and several times higher TPC, TFC as well as AO activity than control cookies, retained well health promoting compounds and maintained an intensely fruity aroma and crispy texture. They were acceptable for consumers according to the hedonic test.

Content of Total Phenolics, Flavan-3-Ols and Proanthocyanidins, Oxidative Stability and Antioxidant Capacity of Chocolate During Storage

Antioxidant (AO) capacity of chocolates with 27, 44 and 75% cocoa was assessed after production and during twelve months of storage by direct current (DC) polarographic assay, based on the decrease of anodic current caused by the formation of hydroxo-perhydroxyl mercury(II) complex (HPMC) in alkaline solutions of hydrogen peroxide at potentials of mercury oxidation, and two spectrophotometric assays. Relative antioxidant capacity index (RACI) was calculated by taking the average value of the AO assay (the sample mass in all assays was identical). Oxidative stability of chocolate fat was determined by differential scanning calorimetry. Measured parameters and RACI were correlated mutually and with the content of total phenols (Folin-Ciocalteu assay), flavan-3-ols (vanillin and p-dimethylaminocinnamaldehyde assay) and proanthocyanidins (modified Bate-Smith assay). During storage, the studied functional and health-related characteristics remained unchanged. Amongst applied AO assays, the DC polarographic one, whose validity was confirmed by two-way ANOVA and F-test, correlated most significantly with oxidative stability (oxidation onset temperature and induction time). In addition, principal component analysis was applied to characterise chocolate types.

Fourier transform infrared spectroscopy provides an evidence of papain denaturation and aggregation during cold storage

Papain is a cysteine protease with wide substrate specificity and many applications. Despite its widespread applications, cold stability of papain has never been studied. Here, we used differential spectroscopy to monitor thermal denaturation process. Papain was the most stabile from 45 °C to 60 °C with ΔG°321 of 13.9±0.3 kJ/mol and Tm value of 84±1 °C. After cold storage, papain lost parts of its native secondary structures elements which gave an increase of 40% of intermolecular β-sheet content (band maximum detected at frequency of 1621 cm(-1) in Fourier transform infrared (FT-IR) spectrum) indicating the presence of secondary structures necessary for aggregation. The presence of protein aggregates after cold storage was also proven by analytical size exclusion chromatography. After six freeze-thaw cycles around 75% of starting enzyme activity of papain was lost due to cold denaturation and aggregation of unfolded protein. Autoproteolysis of papain did not cause significant loss of the protein activity. Upon the cold storage, papain underwent structural rearrangements and aggregation that correspond to other cold denatured proteins, rather than autoproteolysis which could have the commercial importance for the growing polypeptide based industry.

A critical update on endothelial nitric oxide synthase gene variations in women with idiopathic recurrent spontaneous abortion: genetic association study, systematic review and meta-analyses

A number of case-control studies investigated the association between idiopathic recurrent spontaneous abortion (IRSA) and variations in the gene encoding endothelial nitric oxide synthase (NOS3), but yielded contradictory results. Our aim was to test the association of the NOS3 variable number of tandem repeats (VNTR) in intron 4 and +894 G/T single-nucleotide polymorphism (SNP) with IRSA in Slovenian women (148 IRSA and 149 control women), conduct a systematic review of literature on the association between NOS3 gene variations and IRSA, and perform meta-analyses of studies that met the inclusion criteria, defined by virtue of the European Society for Human Reproduction and Embryology evidence-based guidelines for recurrent spontaneous abortion. Genotyping was performed using PCR and restriction fragment length polymorphism methods. The systematic review of literature (English language) was conducted using PubMed and Scopus databases, to 1 November 2014. We determined no association of IRSA with the VNTR in intron 4 and +894 G/T SNP in Slovenian women. Furthermore, 16 case-control studies were identified on the association between 15 NOS3 gene variations and IRSA. However, significant inconsistencies exist in the selection criteria of patients and controls between studies. The meta-analysis of VNTR in intron 4 was performed on five studies (894 patients, 944 controls), whereas the meta-analysis of +894 G/T SNP included six studies (1111 patients, 1121 controls). The association with IRSA was significant for the +894 G/T SNP under the dominant genetic model (GT+TT versus GG) based on fixed (odds ratio (OR) = 1.54, 95% confidence interval (CI) = 1.28-1.86, P = <0.01) and random effects models (OR = 1.54, 95% CI = 1.03-2.31, P = 0.03). In conclusion, the GT and TT genotypes of the +894 G/T SNP in women might contribute to a predisposition to IRSA. Additional genetic association and functional studies in different populations with larger numbers of participants and a uniformly defined IRSA are needed to clarify the contribution of NOS3 +894 G/T gene variation to IRSA.

Can mild bilateral sensorineural hearing loss affect developmental abilities in younger school-age children?

The research study was conducted for the purpose of examining the influence of mild bilateral sensorineural hearing loss (MBSNHL) on developmental abilities of younger school-age children. The sample encompassed 144 children with MBSNHL, aged 7.5-11 (M = 8.85). MBSNHL (20-40 dB HL) was identified by pure tone audiometry. The control group encompassed 160 children with normal hearing. The Acadia test of developmental abilities was used for assessment of developmental abilities. Although statistically significant differences between participants with MBSNHL and those with normal hearing were established in the majority of estimated developmental abilities domains, those differences do not indicate any significant delay in development of assessed abilities, except in the domain of auditory discrimination. The obtained results call for a systematic approach to children with MBSNHL in elementary schools.

Poly(urethane-dimethylsiloxane) copolymers displaying a range of soft segment contents, noncytotoxic chemistry, and nonadherent properties toward endothelial cells

Polyurethane copolymers based on α,ω-dihydroxypropyl poly(dimethylsiloxane) (PDMS) with a range of soft segment contents were prepared by two-stage polymerization, and their microstructures, thermal, thermomechanical, and surface properties, as well as in vitro hemo- and cytocompatibility were evaluated. All utilized characterization methods confirmed the existence of moderately microphase separated structures with the appearance of some microphase mixing between segments as the PDMS (i.e., soft segment) content increased. Copolymers showed higher crystallinity, storage moduli, surface roughness, and surface free energy, but less hydrophobicity with decreasing PDMS content. Biocompatibility of copolymers was evaluated using an endothelial EA.hy926 cell line by direct contact, an extraction method and after pretreatment of copolymers with multicomponent protein mixture, as well as by a competitive protein adsorption assay. Copolymers showed no toxic effect to endothelial cells and all copolymers, except that with the lowest PDMS content, exhibited resistance to endothelial cell adhesion, suggesting their unsuitability for long-term biomedical devices which particularly require re-endothelialization. All copolymers exhibited excellent resistance to fibrinogen adsorption and adsorbed more albumin than fibrinogen in the competitive adsorption assay, suggesting their good hemocompatibility. The noncytotoxic chemistry of these synthesized materials, combined with their nonadherent properties which are inhospitable to cell attachment and growth, underlie the need for further investigations to clarify their potential for use in short-term biomedical devices.

First principle calculations of alkali hydride electronic structures

Electronic structure, volume optimization, bulk moduli, elastic constants, and frequencies of the transversal optical vibrations in LiH, NaH, KH, RbH, and CsH are calculated using the full potential augmented plane wave method, extended with local orbitals, and the full potential linearized augmented plane wave method. The obtained results show some common features in the electronic structure of these compounds, but also clear differences, which cannot be explained using simple empirical trends. The differences are particularly prominent in the electronic distributions and interactions in various crystallographic planes. In the light of these findings we have elaborated some selected experimental results and discussed several theoretical approaches frequently used for the description of various alkali hydride properties.

[Assessment of the degree of maturity in the wall of pancreatic pseudocysts in relation to choice of surgical procedure]

The aim of this study is to present our experience in the diagnosis and treatment of pancreatic pseudocysts. A pancreatic pseudocyst is an incapsulated collection of pancreatic juice, enclosed by nonepithelial elements, containing a high concentration of pancreatic enzymes, bicarbonates and necrotic detritus. It is a common complication of acute pancreatitis and trauma of the pancreas. In the period between 1996 and 2001, 53 surgical procedures were performed for pancreatic pseudocyst at the Institute for Digestive Diseases (First Surgical University Hospital), 35 male patients (67%) and 17 female patients (33%) underwent surgery. In 39 (75%) patients the method of choice was cystojejunostomy by Roux. In 4 cases distal pancreatectomy for pseudocysts localized within the pancreatic tail was performed, complete pseudocyst excision only was performed in one case and complete pseudocyst excision combined with cystojejunostomy was also performed in one case. Cystogastrostomy and drainage in one case and partial cystectomy and drainage also in one case. Surgical internal drainage is the method of choice for the treatment of pancreatic pseudocysts, involving low morbidity and mortality rates.

[Spontaneous massive retroperitoneal hemorrhage from an adrenal gland cyst]

Adrenal cyst are rare disease. Bleeding, particularly massive, from these cysts is even rarer. The cyst causing spontaneous massive retroperitoneal bleeding in a 17 year old girl is presented. Adrenalectomy was successfully carried out. The patient stayed symptom free so far.

The effect of a compulsory curriculum on ethical attitudes of medical students

The purpose of the present study was to assess the influence of a compulsory curriculum on first-year medical students. The ethical attitude study was performed at the School of Medicine, University of Rijeka, Croatia. The samples consisted of 171 medical students (68 males and 103 females) interviewed at the beginning of the first year of studies. Some of them, namely 143 (56 males and 87 females) were interviewed again at the end of the same academic year. Data were analysed by applying factor analysis under principal component model and varimax criterion as the rotation model. The results clearly show that the current compulsory curriculum without formal ethical education has a limited influence on first-year medical students. That points to the obvious necessity to implement the medical ethics in the course of medical education.

Specific dephosphorylation of phosphopeptides by the yeast alkaline phosphatase encoded by PHO8 gene

Partially purified nonspecific phosphate-repressible alkaline phosphatase from Saccharomyces cerevisiae encoded by PHO8 gene (rALPase), efficiently dephosphorylates phosphohistones and a variety of phosphopeptides. The pho8 mutant, constructed by disruption of the chromosomal counterpart of the PHO8 gene, is lacking in phosphatase activity toward phosphopeptides, confirming that this activity is actually due to rALPase. rALPase activity tested on phosphopeptides is maximum in the pH range 6.5-7.5 and the Km values for these substrates are in the micromolar range, suggesting a possible physiological relevance of this enzyme as a protein phosphatase. rALPase dephosphorylates phosphotyrosyl more efficiently than phosphoseryl peptides, but is poorly active on phosphothreonyl peptides. Its specificity towards synthetic peptides and insensitivity to specific inhibitors and activators of authentic protein phosphatases indicate that rALPase differs from both Ser/Thr- and Tyr-specific protein phosphatases. This conclusion is consistent with the lack of homology with any class of known protein phosphatases.