Cys34 thiol group of human serum albumin : possibilities and importance of determination in clinical practise

Humani serum albumin (HSA) ima više fizioloških funkcija, jedna od njih jeodbrana organizma od oksidativnog i/ili karbonilnog stresa. Istaknuta funkcija je posledicaprisustva jedne slobodne tiolne grupe ostatka Cys34 na površini njegovih molekula.Određivanje sadržaja HSA-SH grupa bi moglo biti pogodno za procenu stepenaoksidativnog i/ili karbonilnog stresa u različitim patološkim stanjima. Da bi našlo primenuu kliničkoj praksi, u prvom koraku potrebno je izolovati HSA iz seruma ili plazme, a potomodrediti sadržaj tiolnih grupa.Ispitivanjem pouzdanosti metode izolovanja HSA afinitetnom hromatografijom saCibacron Blue (CB) iz seruma zdravih osoba i dijabetičara, i kvantifikacije tiolne grupe,ustanovljeno je da je sadržaj HSA-SH grupa veći za 6 do 33 % od ukupnog sadržaju tiolaseruma, odnosno da je tačnost metode mala (recovery sadržaja HSA-SH grupa od 113,6 do130,1%). Utvrđena diskrepancija nije posledica uslova izolovanja (zapremina uzorka,karakteristike matriksa, protok kroz kolonu i vreme potrebno za izolovanje HSA iodređivanje sadržaja SH grupa), prisustva pufera za izolovanje i drugih proteina uizolovanom HSA (čistoće od 88,4 do 91,4 %), uticaja proteina, malih molekula i jonaprisutnih u serumu na određivanje HSA-SH, već selekcije HSA molekula od strane CBprema njihovoj konformaciji. Promena konformacije (utvrđena emisionom fluorescentnomspektroskopijom i CD), odnosno selekcija zavisi od vrste i broja molekula masnih kiselina(Mk) vezanih za HSA. Osim toga, priroda i broj Mk vezanih za HSA doprinose povećanjureaktivnosti HSA-SH grupa: konstanta brzine pseudo prvog reda za reakciju HSA-SHgrupe s DTNB u CB-vezanoj-HSA frakciji (21.74x10-3 s-1) je veća u odnosu na nevezanu-HSA frakciju (11.2x10-3 s-1), kao i u grupi dijabetičara (n=20) (20.9x10-3 s-1) u odnosu nakontrolnu grupu (n=17) (12.9x10-3 s-1). Recovery vrednosti sadržaja Cys34-SH grupa u CBvezanim-HSA frakcijama (od 98,5 do 101,7 %), dobijene nakon odmašćivanja HSA,potvrdile su da metoda izolovanja HSA afinitetnom hromatografijom nije pogodna zaodređivanje sadržaja HSA-SH grupa za kliničke svrhe.U cilju postizanja veće pouzdanosti u izvođenju zaključaka o promenama sadržajaHSA-SH grupa u različitim patološkim stanjima, optimizovana je metoda izolovanja HSAiz seruma dvostepenim taloženjem sa amonijum-sulfatom (AS) (zasićenje AS od 54 % uprvom i od 70 % u drugom koraku), sa prinosom HSA od 69,7 ± 4,4 %. Način taloženjaHSA (sa čvrstim AS-om ili zasićenim rastvorom AS-a) i uklanjanje AS-a iz izolovanogpreparata, ne utiče značajno na čistoću izolovanog HSA, u kojem je pored monomera(zastupljenost 91,9 ± 3,6 %) dokazano (SDS PAG elektroforezeom i imunoblotom)prisustvo dimera HSA (oko 10 %), tako de se predloženim postupkom izoluje HSA čistoćeoko 100 %. Predložena metoda je jednostavna, brza i jeftina, što je važno za kliničkupraksu. Omogućava precizno (RSD 3,2 %), tačno (recovery vrednost 101,2 ± 2,0 %, zaopseg fizioloških vrednosti od 0,25 do 0,75 mol-SH/mol HSA) i pouzdano (doprinos HSASHukupnom sadržaju tiola u serumu kod zdravih osoba iznosi 83,2 ± 5,3 %) određivanjesadržaja HSA-SH grupa. Predložena metoda može da se primeni i za izolovanje HSA izplazme (ne postoji statistički značajna razlika između sadržaja Cys34-SH grupa HSAizolovanog iz plazme ili seruma (0.574 ± 0.026; 0.570 ± 0.028 mol-SH/mol HSA, resp.).Mogućnost i značaj određivanja sadržaja HSA Cys34-SH grupe kao markera ukliničkoj praksi, proverena je određivanjem sadržaja HSA-SH grupa i ukupnih tiola ugrupi: obolelih od tipa 2 dijabetesa (n=23) i kontrolnoj grupi (n=17); kod trudnica sa (n=15)i bez preeklampsije (n=15). U oba patološka stanja, kod pacijenata sa tipom 2 dijabetesa isa preeklampsijom, dobijeno je statistički značajno smanjenje (p<0.05) sadržaja HSA-SHgrupa i ukupnih tiola seruma u odnosu na odgovarajuće kontrolne grupe. Određivanjesadržaja HSA Cys34-SH grupa se može primenjivati kao marker procene karbonilnogstresa u ovim patološkim stanjima. Pored toga, nađeno je da se reaktivnost tiolne grupeCys34 ostatka u ovim stanjima menja, što ima važne implikacije na mogućnost modulacijereaktivnosti (antioksidativnih svojstava) tiolne grupe pomoću suplemenata (na primer.masnih kiselina).Human serum albumin (HSA) has a multitude of physiological functions, andone of them is to defend the organism against oxidative and/or carbonyl stress. Thisprominent function is enabled by the presence of single free Cys34 thiol group at thesurface of HSA molecules. Determination of HSA-SH group content could be a suitableparameter for oxidative and/or carbonyl stress level assesemnet in different pathologicalstates. In order to become aplicable in clinical practice, it is necessary to isolate HSAfrom serum or plasma in the first, and then to determine the content of thiol group.Monitoring of the reliability of affinity chromatography with Cibacron Blue(CB) for HSA isolation from serum of healthy and diabetic persons, and thiol groupquantification, showed that HSA-SH group content was higher from 6 to 33% than thetotal serum thiols content, i.e. that the accuracy of this method is low (HSA-SH groupcontent recovery ranging from 113.6 to 130.1%). This discrepancy is not caused by theisolation conditions (sample volume, matrix charateristics, column flow and the timeneeded for HSA isolation and SH group content determination), presence of buffer forHSA isolation and other proteins in isolated HSA preparation (purity range from 88.4 to91.4%), influence of proteins, small molecules and ions present in the serum on theHSA-SH content determination, but the selection of HSA molecules by CB according totheir conformations. The change in conformation (determined by emmission flourescentspectroscopy and CD), and accordingly the selection, depend on the type and thenumber of fatty acid (FA) molecules bound to HSA. Besides that, the nautre and thenumber of HSA bound FAs contribute to the increase in HSA-SH group reactivity:pseudo-first order rate constant for the reaction HSA-SH group with DTNB in CBbound fraction (21.74x10-3 s-1) is higher compared to unbound HSA fraction (11.2x10-3s-1), as well as in diabetic group (n=20) (20.9x10-3 s-1) compared to the controls (n=17)(12.9x10-3 s-1). Recovery values for Cys34-SH group content in CB bound HSAfractions (from 98,5 to 101,7 %), acquired after HSA defatting, confirmed that isolationof HSA by affinity chromatography is not suitable for determination of HSA-SH groupcontent in clinical practice.A two step ammonium sulphate (AS) precipitation method for HSA isolationfrom serum (AS saturation from 54% in first step and 70% in second step), with HSAyield of 69.7±4.4%, has been optimised in order to make more reliabile conclusionsabout the changes in HSA-SH group content in different pathological states. HSAprecipitation method (with solid AS or saturated AS solution) and the removal of ASfrom isolated preparation, has no significant influence on the purity of isolated HSA,where the presence of HSA dimer (about 10 %) was detected (by SDS PAGelectrophoresis and immunoblot) along with the HSA monomer (91.9%±3.6%abundance), so the purity of isolated HSA can be regarded as 100%. The proposedmethod is simple, fast and low cost, which is of greate importance for good clinicalpractice. It allows for precise (RSD 3,2%), accurate (with 101,2±2% recovery forphysiological values from 0,25 to 0,75 mol -SH/mol HSA) and reliable (HSA-SHcontribution to the total serum thiols content in healthy persons is 83,2 ± 5,3 %)determination of HSA-SH group content. In addition, proposed method could beaplicable for isolation of HSA from plasma samples (there is no significant statisticaldifferrence between the HSA Cys34-SH content isolated form plasma and serum (0.574± 0.026; 0.570 ± 0.028 mol-SH/mol HSA, resp.).The possibility and the importance of HSA Cys34-SH content determination as amarker in clinical practice, was tested by the determination of HSA-SH and total thiolscontent in group of: patients with diabetes mellitus type II (n=23) and control group(n=17); pregnant women with (n=15) and without preeclampsia (n=15). In bothpahtological states, in diabetic patients and pregnant women with preeclampsia, there isa statistically significant decrease (p<0.05) in HSA-SH group content as well as in totalserum thiols content compared to appropriate controls. Determination of HSA Cys34-SH content could be applied as a marker for carbonyl stress level assesement in thesepthological states. In addition, it was found that the reactivity of Cys34 thiol group inthese pathological states changes, which is an important implication for possiblemodulation of its reactivity (antioxidant properties) by supplements (eg. fatty acids)

Comparative digestomics of Tropomyosin of vertebrates and invertebrates in real food matrix

Shellfish, is a highly nutritive food resource in the world, but also among the eight allergic food groups accounting for approximately 90% of all immunoglobulin E food allergies worldwide [1]. This work focuses on the only well-recognized major allergen muscle protein tropomyosin(TM) that is responsible for cross reactivity between shellfish and other invertebrates [2]. By contrary, TM of vertebrates (chicken, pig, cow) is not a prominent allergen. The stability of food allergens to digestion is an important factor contributing to their allergenicity. Most in vitro digestibility studies are based on the protein extract rather than whole food matrix thus overlooking its effect on TM stability [3]. Our objective was to primarily test the pepsin digestibility of invertebrates and vertebrates (raw and thermally treated based on their real life consumption modes) mimicking the gastric digestion under standardized conditions. To closely observe and compare the vertebrates’ and invertebrates’ TM stability, we aimed to perform the specific antibody based western blot analysis with two primary antibodies; ❶Rabbit anti shrimp TM antibody (invertebrates), and ❷ Rabbit anti human TM antibody (species reactivity to vertebrates). Methods: Thermal treatment of selected samples to compare TM heat stability, Standardized static in vitro methods of simulated gastric digestion[4] for the evaluation and comparison of TM resistance to pepsin, Sodium Dodecyl Sulfate-Polyacryl amide Gel Electrophoresis (SDS-PAGE) of digesta supernatant under reducing and non-reducing conditions to quantify proteins and compare thermally treated invertebrates and vertebrates protein profiles focusing on TM, specific antibody based semi dry Western blot analysis. Results and discussions: SDS-PAGE analysis of vertebrates and invertebrates’ samples showed a range of proteins in varied amounts between 10-250 kDa. Depending upon samples, varied numbers of prominent protein bands were observed including the distinct bands corresponding with the molecular weights of TM(37-39kDa). In agreement with publications, TM was, indeed, resistant against pepsin digestion as well as thermal treatment prominently in case of invertebrates. This was confirmed upon Ab based Western blot analysis. Our results show that, upon thermal treatment, TM is partially degraded as is observed in case of raw and cooked beef electrophoretic profile as well as WB analysis. Significantly, upon pepsin digestion, TM (allergen) is completely degraded in vertebrates in contrast to the invertebrates’ TM (which is pepsin resistant and heat stable). This result provides an insight on the differences in digestibility of allergenic versus non-allergenic TM in real food matrix and upon thermal treatments of solid food samples. Methods: Thermal treatment of selected samples to compare TM heat stability, Standardized static in vitro methods of simulated gastric digestion[4] for the evaluation and comparison of TM resistance to pepsin, Sodium Dodecyl Sulfate-Polyacryl amide Gel Electrophoresis (SDS-PAGE) of digesta supernatant under reducing and non-reducing conditions to quantify proteins and compare thermally treated invertebrates and vertebrates protein profiles focusing on TM, specific antibody based semi dry Western blot analysis. Results and discussions: SDS-PAGE analysis of vertebrates and invertebrates’ samples showed a range of proteins in varied amounts between 10-250 kDa. Depending upon samples, varied numbers of prominent protein bands were observed including the distinct bands corresponding with the molecular weights of TM(37-39kDa). In agreement with publications, TM was, indeed, resistant against pepsin digestion as well as thermal treatment prominently in case of invertebrates. This was confirmed upon Ab based Western blot analysis. Our results show that, upon thermal treatment, TM is partially degraded as is observed in case of raw and cooked beef electrophoretic profile as well as WB analysis. Significantly, upon pepsin digestion, TM (allergen) is completely degraded in vertebrates in contrast to the invertebrates’ TM (which is pepsin resistant and heat stable). This result provides an insight on the differences in digestibility of allergenic versus non-allergenic TM in real food matrix and upon thermal treatments of solid food samples

Comparative digestomics of Tropomyosin of vertebrates and invertebrates in real food matrix

Shellfish, is a highly nutritive food resource in the world, but also among the eight allergic food groups accounting for approximately 90% of all immunoglobulin E food allergies worldwide [1]. This work focuses on the only well-recognized major allergen muscle protein tropomyosin(TM) that is responsible for cross reactivity between shellfish and other invertebrates [2]. By contrary, TM of vertebrates (chicken, pig, cow) is not a prominent allergen. The stability of food allergens to digestion is an important factor contributing to their allergenicity. Most in vitro digestibility studies are based on the protein extract rather than whole food matrix thus overlooking its effect on TM stability [3]. Our objective was to primarily test the pepsin digestibility of invertebrates and vertebrates (raw and thermally treated based on their real life consumption modes) mimicking the gastric digestion under standardized conditions. To closely observe and compare the vertebrates’ and invertebrates’ TM stability, we aimed to perform the specific antibody based western blot analysis with two primary antibodies; ❶Rabbit anti shrimp TM antibody (invertebrates), and ❷ Rabbit anti human TM antibody (species reactivity to vertebrates). Methods: Thermal treatment of selected samples to compare TM heat stability, Standardized static in vitro methods of simulated gastric digestion[4] for the evaluation and comparison of TM resistance to pepsin, Sodium Dodecyl Sulfate-Polyacryl amide Gel Electrophoresis (SDS-PAGE) of digesta supernatant under reducing and non-reducing conditions to quantify proteins and compare thermally treated invertebrates and vertebrates protein profiles focusing on TM, specific antibody based semi dry Western blot analysis. Results and discussions: SDS-PAGE analysis of vertebrates and invertebrates’ samples showed a range of proteins in varied amounts between 10-250 kDa. Depending upon samples, varied numbers of prominent protein bands were observed including the distinct bands corresponding with the molecular weights of TM(37-39kDa). In agreement with publications, TM was, indeed, resistant against pepsin digestion as well as thermal treatment prominently in case of invertebrates. This was confirmed upon Ab based Western blot analysis. Our results show that, upon thermal treatment, TM is partially degraded as is observed in case of raw and cooked beef electrophoretic profile as well as WB analysis. Significantly, upon pepsin digestion, TM (allergen) is completely degraded in vertebrates in contrast to the invertebrates’ TM (which is pepsin resistant and heat stable). This result provides an insight on the differences in digestibility of allergenic versus non-allergenic TM in real food matrix and upon thermal treatments of solid food samples. Methods: Thermal treatment of selected samples to compare TM heat stability, Standardized static in vitro methods of simulated gastric digestion[4] for the evaluation and comparison of TM resistance to pepsin, Sodium Dodecyl Sulfate-Polyacryl amide Gel Electrophoresis (SDS-PAGE) of digesta supernatant under reducing and non-reducing conditions to quantify proteins and compare thermally treated invertebrates and vertebrates protein profiles focusing on TM, specific antibody based semi dry Western blot analysis. Results and discussions: SDS-PAGE analysis of vertebrates and invertebrates’ samples showed a range of proteins in varied amounts between 10-250 kDa. Depending upon samples, varied numbers of prominent protein bands were observed including the distinct bands corresponding with the molecular weights of TM(37-39kDa). In agreement with publications, TM was, indeed, resistant against pepsin digestion as well as thermal treatment prominently in case of invertebrates. This was confirmed upon Ab based Western blot analysis. Our results show that, upon thermal treatment, TM is partially degraded as is observed in case of raw and cooked beef electrophoretic profile as well as WB analysis. Significantly, upon pepsin digestion, TM (allergen) is completely degraded in vertebrates in contrast to the invertebrates’ TM (which is pepsin resistant and heat stable). This result provides an insight on the differences in digestibility of allergenic versus non-allergenic TM in real food matrix and upon thermal treatments of solid food samples

Fatty acids composition of the most common bivalves in Korean diet

Consumption of bivalve molluscs, such as oysters, mussels, clams and scallops, makes a significant part of the daily Korean diet. Bivalves provide high quality proteins with all the dietary-essential amino acids, lipids, vitamins, minerals and other bioactive nutrients, which offer a variety of health benefits to the consumer [1]. This food contains less than 5 percent of total fat, so it is considered a low-fat food. Beside the amount of total fat, the proportions of saturated, monounsaturated and polyunsaturated fatty acids (FA) (S, M and P, respectively), as well as ratio of n-3 (ω-3) and n-6 (ω-6) P in food are very important for the health diet [2]. Fourteen species of bivalves Anadara broughtonii (AB), Ruditapes philippinarum (Manila clam (RP)), Tegillarca granosa (TG), Pecten yessoensis (Yesso scallop (YS), Argopecten spp. (small scallop (SS), Chlamys farreri farreri (CF), Cyclina sinensis (CS), Leukoma jedoensis (LJ), Mytilus califorianus (MCa) Mytilus galloprovancialis (MG), Maretrix lusoria (ML), Mactra quadrangularis (MQ), Sinovacula constricta (SC) and Crassostrea gigas (Pacific oyster (PC)) were bought in two fish markets in Incheon, Korea, in order to determine FA composition using GC/EI-MS of fatty acid methyl esters (FAME). The FAME were identified by comparing their retention times with those of the FAME standards or by comparing their mass spectra with those stored in the NIST Mass Spectral Library. In the bivalve samples, 43 different FA were identified, of which 10 were S, 12 M and 13 P, other FA were 7 methyl-FA and 1 hydroxyl-FA. The P/S ratio and ω-6/ω-3 P ratio are the most significant markers of lipid composition in a healthy diet and both should be close to 1 [3]. Among analysed species, only YS and SS have P/S ratio close to 1 (1,20 and 1.16, respectively), while other species have value between 0.07 and 0.73. The obtained values for ω-6/ω-3 P ratio were from 0.008 to 0.55, which indicates that bivalve molluscs are the valuable source of ω-3 P (EPA and DHA). These ω-3 P play important roles in growth, development, and maintenance of health

Fatty acids composition of the most common bivalves in Korean diet

Consumption of bivalve molluscs, such as oysters, mussels, clams and scallops, makes a significant part of the daily Korean diet. Bivalves provide high quality proteins with all the dietary-essential amino acids, lipids, vitamins, minerals and other bioactive nutrients, which offer a variety of health benefits to the consumer [1]. This food contains less than 5 percent of total fat, so it is considered a low-fat food. Beside the amount of total fat, the proportions of saturated, monounsaturated and polyunsaturated fatty acids (FA) (S, M and P, respectively), as well as ratio of n-3 (ω-3) and n-6 (ω-6) P in food are very important for the health diet [2]. Fourteen species of bivalves Anadara broughtonii (AB), Ruditapes philippinarum (Manila clam (RP)), Tegillarca granosa (TG), Pecten yessoensis (Yesso scallop (YS), Argopecten spp. (small scallop (SS), Chlamys farreri farreri (CF), Cyclina sinensis (CS), Leukoma jedoensis (LJ), Mytilus califorianus (MCa) Mytilus galloprovancialis (MG), Maretrix lusoria (ML), Mactra quadrangularis (MQ), Sinovacula constricta (SC) and Crassostrea gigas (Pacific oyster (PC)) were bought in two fish markets in Incheon, Korea, in order to determine FA composition using GC/EI-MS of fatty acid methyl esters (FAME). The FAME were identified by comparing their retention times with those of the FAME standards or by comparing their mass spectra with those stored in the NIST Mass Spectral Library. In the bivalve samples, 43 different FA were identified, of which 10 were S, 12 M and 13 P, other FA were 7 methyl-FA and 1 hydroxyl-FA. The P/S ratio and ω-6/ω-3 P ratio are the most significant markers of lipid composition in a healthy diet and both should be close to 1 [3]. Among analysed species, only YS and SS have P/S ratio close to 1 (1,20 and 1.16, respectively), while other species have value between 0.07 and 0.73. The obtained values for ω-6/ω-3 P ratio were from 0.008 to 0.55, which indicates that bivalve molluscs are the valuable source of ω-3 P (EPA and DHA). These ω-3 P play important roles in growth, development, and maintenance of health

How the sialylation level of serum N-acetyl-beta-D-glucosaminidase A form in Type 1 diabetes mellitus influences their activity?

It was verified that the serum N-acetyl-beta-D-glucosaminidase (NAG) activity is elevated in diabetes, but there are no reports about changes in the sialic acid (SA) content in the carbohydrate parts of the NAG A form and its influence on the total changes in NAG activity in type 1 diabetes mellitus patients with and without secondary complications. The NAG A form was isolated from the serum of 81 insulin-dependent diabetes mellitus (IDDM) patients with and without secondary complications (retinopathy, polyneuropathy and nephropathy) and 25 healthy persons, and purified and characterised. The content of alpha-2,6-bound SA, the isoenzyme patterns of the purified A form, and the total NAG and A form activities were determined. In all diabetic groups, the sialylation levels of the A form were 2-3.5 times lower compared to control, while their acidities (fractions with pI 4.25-5.1) increased, particularly with progression of secondary complications. Total serum NAG activities and percentages of A form were significantly higher (P lt 0.001) in all diabetic groups and negatively correlated with the alpha-2,6-bound SA content of the A form. In addition, they decreased as secondary diabetic complications became more complex. The observed changes could be the consequence of structural changes in the A form due to significant increases in its acidity, i.e., negative charge, which originated from groups other than SA

Current Insights into the Effects of Dietary α-Linolenic Acid Focusing on Alterations of Polyunsaturated Fatty Acid Profiles in Metabolic Syndrome

The plant-derived α-linolenic acid (ALA) is an essential n-3 acid highly susceptible to oxidation, present in oils of flaxseeds, walnuts, canola, perilla, soy, and chia. After ingestion, it can be incorporated in to body lipid pools (particularly triglycerides and phospholipid membranes), and then endogenously metabolized through desaturation, elongation, and peroxisome oxidation to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), with a very limited efficiency (particularly for DHA), beta-oxidized as an energy source, or directly metabolized to C18-oxilipins. At this moment, data in the literature about the effects of ALA supplementation on metabolic syndrome (MetS) in humans are inconsistent, indicating no effects or some positive effects on all MetS components (abdominal obesity, dyslipidemia, impaired insulin sensitivity and glucoregulation, blood pressure, and liver steatosis). The major effects of ALA on MetS seem to be through its conversion to more potent EPA and DHA, the impact on the n-3/n-6 ratio, and the consecutive effects on the formation of oxylipins and endocannabinoids, inflammation, insulin sensitivity, and insulin secretion, as well as adipocyte and hepatocytes function. It is important to distinguish the direct effects of ALA from the effects of EPA and DHA metabolites. This review summarizes the most recent findings on this topic and discusses the possible mechanisms

Citric Acid Cross-Linked Gelatin-Based Composites with Improved Microhardness

The aim of this study is to investigate the influence of cross-linking and reinforcements in gelatin on the physico-mechanical properties of obtained composites. The gelatin-based composites cross-linked with citric acid (CA) were prepared: gelatin type B (GB) and β-tricalcium phosphate (β-TCP) and novel hybrid composite GB with β-TCP and hydroxyapatite (HAp) particles, and their structure, thermal, and mechanical properties were compared with pure gelatin B samples. FTIR analysis revealed that no chemical interaction between the reinforcements and gelatin matrix was established during the processing of hybrid composites by the solution casting method, proving the particles had no influence on GB cross-linking. The morphological investigation of hybrid composites revealed that cross-linking with CA improved the dispersion of particles, which further led to an increase in mechanical performance. The microindentation test showed that the hardness value was increased by up to 449%, which shows the high potential of β-TCP and HAp particle reinforcement combined with CA as a cross-linking agent. Furthermore, the reduced modulus of elasticity was increased by up to 288%. Results of the MTT assay on L929 cells have revealed that the hybrid composite GB-TCP-HA-CA was not cytotoxic. These results showed that GB cross-linked with CA and reinforced with different calcium phosphates presents a valuable novel material with potential applications in dentistry

Citric Acid Cross-Linked Gelatin-Based Composites with Improved Microhardness

The aim of this study is to investigate the influence of cross-linking and reinforcements in gelatin on the physico-mechanical properties of obtained composites. The gelatin-based composites cross-linked with citric acid (CA) were prepared: gelatin type B (GB) and β-tricalcium phosphate (β-TCP) and novel hybrid composite GB with β-TCP and hydroxyapatite (HAp) particles, and their structure, thermal, and mechanical properties were compared with pure gelatin B samples. FTIR analysis revealed that no chemical interaction between the reinforcements and gelatin matrix was established during the processing of hybrid composites by the solution casting method, proving the particles had no influence on GB cross-linking. The morphological investigation of hybrid composites revealed that cross-linking with CA improved the dispersion of particles, which further led to an increase in mechanical performance. The microindentation test showed that the hardness value was increased by up to 449%, which shows the high potential of β-TCP and HAp particle reinforcement combined with CA as a cross-linking agent. Furthermore, the reduced modulus of elasticity was increased by up to 288%. Results of the MTT assay on L929 cells have revealed that the hybrid composite GB-TCP-HA-CA was not cytotoxic. These results showed that GB cross-linked with CA and reinforced with different calcium phosphates presents a valuable novel material with potential applications in dentistry

The Potential Benefits of Acute Aronia Juice Supplementation on Physical Activity Induced Alterations of the Serum Protein Profiles in Recreational Runners: A Pilot Study

Intensive physical activity (PA) can lead to proteinuria and, consequently, serum protein profiles in athletes. Therefore, the aim of this study was to investigate the effects of acute aronia juice consumption before a simulated half-marathon race on serum protein profiles in recreational runners. The pilot study was designed as a single-blind, placebo-controlled, crossover study, with 10 male participants who consumed aronia juice (containing 1.3 g polyphenols) or placebo before the race. The blood levels of total proteins, albumin, the non-albumin fractions gamma, beta, alpha2 and alpha1, as well as renal function parameters, were determined before and 15 min, 1 h and 24 h after the race. The significant changes in urea, creatinine and uric acid levels were noticed at selected time points in both groups. In the placebo group, a significant decrease in total proteins (p < 0.05) was observed 24 h after the race, along with an increase in gamma fraction abundance (p < 0.05). In addition, urea and uric acid levels returned to baseline only in the aronia group 24 h after the race. Thus, according to the results obtained, acute aronia juice supplementation before intensive PA could influence the transient change in renal function and PA-induced protein loss in recreational runners