Značaj granične inspekcije u kontroli trovanja histaminom iz konzervi od tuna

Republika Srbija nema sopstvenu proizvodnju morskih riba i poseduje svega nekoliko objekata za preradu morske ribe. Sva morska riba se uvozi, samim tim su i sve konzerve od komada i komadića tunja na našem tržištu uvezene. Uvoz konzervi od tunja, kao i svih drugih ribljih proizvoda prilikom ulaska u našu zemlju se mora podvrgnuti kontroli granične veterinarske inspekcije. Odmah nakon prispeća pošiljke na granični prelaz lice odgovorno za pošiljku, pored obrasca zajedničkog veterinarskog ulaznog dokumenta za proizvode, podnosi i zahtev za veterinarsko sanitarni pregled. Svaka pošiljka konzervi od tunja u uvozu u Republiku Srbiju mora biti podvrgnuta pregledu dokumentacije, identifikaciji pošiljke i fizičkom, hemijskom, mikrobiološkom i senzorskom pregledu. Sadržaj histamina u ribama i proizvodima od riba je pre svega kriterijum bezbednosti hrane obzirom da utiče na zdravlje ljudi, ali je u isto vreme i pokazatelj higijene procesa i svežine proizvoda. Cilj ove studije je da se obezbede informacije o prisustvu histamina u uvezenim konzervama od tunja i da se ukaže na značaj granične inspekcije u kontroli histaminske intoksikacije koja nastaje kao posledica konzumiranja konzervi od tunja sa povišenim sadržajem histamina. Tokom jednogodišnje studije (od januara do decembra 2014. godine) ispitano je 97 proizvodnih partija uvezenih konzervi od tunja. Svih 97 proizvodnih partija je uzorkovano tokom granične inspekcije i ispitano u laboratorijama Naučnog instituta za veterinarstvo „Novi Sad“. Ispitivanje sadržaja prisustva histamina u konzervama od tunja je urađeno ELISA metodom sa test kitom HIS-E02 (Immunolab GmbH, Germany). Rezultati studije pokazuju da je 3,09 % proizvodnih partija uvezenih konzervi od tunja imalo nezadovoljavajuće povećan nivo sadržaja histamina i da nisu bezbedne za ljudsku ishranu. Sve proizvodne partije kod kojih je dokazan povećan nivo histamina, odnosno koje su proglašene za nebezbedne za ljudsku ishranu su vraćene, a uvoz je zabranjen. Granična inspekcija, tj. ispitivanje pri graničnoj inspekcije predstavlja značajnu preventivnu meru u sprečavanju histaminske intoksikacije kao posledice konzumiranja konzervi od tunja sa povišenim sadržajem histamina

Uticaj matriksa na određivanje antiparazitika HPLC metodom

Tečna hromatografija visokih performansi (HPLC, tečna hromatografija pod visokim pritiskom) je oblik kolonske hromatografije koji se često koristi u analitičkoj hemiji. HPLC se koristi za razdvajanje komponenti iz smese na osnovu hemijskih interakcija između supstance koja se analizira i stacionarne faze u koloni. Princip rada HPLC-a je forsiranje prolaska analizirane supstance (ili smeše) kroz kolonu (cev napunjenu materijalom sitnih čestica, a time i velike površine) pumpanjem tečnosti (mobilna faza) pod visokim pritiskom kroz kolonu. Unosi se mala zapremina uzorka u tok mobilne faze i na osnovu specifičnih hemijskih i fizičkih interakcija, dolazi do različitog zadržavanja komponenata smeše. Vreme zadržavanja zavisi od prirode supstance koja se analizira, stacionarne faze i sastava mobilne faze. Vreme za koje se supstanca eluira (dođe do kraja kolone) naziva se retenciono vreme i one je karakteristično za određenu supstancu. Korištenje visokog pritiska povećava linearnu brzinu i daje komponentama manje vremena za zadržavanje, što poboljšava rezoluciju hromatograma. Koriste se uobičajeni rastvarači, čisti ili u bilo kojoj kombinaciji (npr. voda, metanol, organski rastvarači, itd). Voda može sadržavati i neki pufer, kako bi se poboljšalo razdvajanje. Moguće je koristiti i gradijentno eluiranje, što podrazumeva promenu sastava mobilne faze u toku eluiranja. Uređaj za HPLC se sastoji od sledećih komponenata: rezervoar mobilne faze, pumpe i injektora. Detektor ima važnu ulogu da određivanja komponenti koje izlaze iz kolone nakon eluiranja. Detektor generiše električni signal koji je proporcionalan intenzitetu neke osobine mobilne faze ili supstance koja se eluira. Tipovi detektora u HPLC-u su: UV-VIS detektor, fluorescentni detektor, elektrohemijski detektor, detektor indeksa loma i maseni spektrometar (MS). Uticaj matrixa uzorka koji se analizra ima veliki uticaj na izlazne analiticke rezultate. Kako bi se eliminisao uticaj matrixa pozeljno je uraditi kalibraciju kroz matrix, na blank uzorku koji ne sadrzi analite od interesa (Olives, 2006). U našoj studiji smo ukazali na značaj kalibracije kroz matrix, kako bismo neutralisali negov nepovoljan uticaj na rezultat. S tim ciljem je urađena i analiza uzoraka mesa ribe koja je spajkovana sa razlicitim koncentracijama parazitika. Uzorci su ekstrahovani sa acetonitrilom u prisustvu soli, anhidrovanog magnezijum sulfata i natrijum acetate. Kvantifikacija prečišenog ekstrakta je urađena na Thermo HPLC-u, sa UV detektorom. Na osnovu sprovedenog ispitivanja utvrđeno je da procenat recovery kod kalibracije kroz matrix se krece u opsegu od 75-95 % a u slučaju kalibracije sa standardima kreće se u opsegu od 40-55%. Zbog značaja praćenja parazitika u mesu ribe neophodno je optimizovati uslove analize s ciljem dobijanja pouzdanih rezultata i pračenja kvaliteta proizvoda

Optimization of tribological properties in A356/10SiC/5Gr hybrid composite using Taguchi method

In present study, the tribological behavior of hybrid composites with A356 aluminum alloy matrix reinforced with 10 wt.% of SiC and 5 wt.% of graphite was investigated using the Taguchi method. The composites were produced by the compocasting procedure. The tribological properties were studied using block-on-disk tribometer under lubricated sliding conditions at different normal loads (40N, 80N and 120N), sliding speeds (0.25 m/s, 0.5 m/s and 1 m/s) and sliding distances (150 m, 300 m and 1200 m). Analysis of the wear rate results was performed using the ANOVA technique. The lowest level of wear rate corresponded to the contact conditions with normal load of 40N, sliding speed of 1.0 m/s and sliding distance of 1200 m

Optimization of wear behaviour in aluminium hybrid composites using Taguchi method

Tribological behaviour of a hybrid composite with the aluminium alloy base A356 reinforced by 10 wt. % SiC and 5 wt. % of graphite is treated in this paper. The optimization of tribological behaviour was conducted through the application of Taguchi method. Hybrid composites were obtained in the compocasting procedure. Tribological examinations were executed on the block on disc tribometer with the variation of two different load values (20 and 30 N), three sliding speed values (0.25, 0.5 and 1 m/s) and three sliding distance values (30, 90 and 150 m). All the examinations were carried out in conditions with no lubrication existing. The analysis of the wear rate was conducted using the ANOVA method of analysis. The greatest impact on the wear rate has the load (62.11 %), then the sliding speed (32.88 %), and the least the sliding distance (2.57 %). The interaction of the factors does not have a significant impact on the wear rate

Impaired Retromer Function in Niemann-Pick Type C Disease Is Dependent on Intracellular Cholesterol Accumulation

Niemann-Pick type C disease (NPC) is a rare inherited neurodegenerative disorder characterized by an accumulation of intracellular cholesterol within late endosomes and lysosomes due to NPC1 or NPC2 dysfunction. In this work, we tested the hypothesis that retromer impairment may be involved in the pathogenesis of NPC and may contribute to increased amyloidogenic processing of APP and enhanced BACE1-mediated proteolysis observed in NPC disease. Using NPC1-null cells, primary mouse NPC1-deficient neurons and NPC1-deficient mice (BALB/cNctr-Npc1m1N), we show that retromer function is impaired in NPC. This is manifested by altered transport of the retromer core components Vps26, Vps35 and/or retromer receptor sorLA and by retromer accumulation in neuronal processes, such as within axonal swellings. Changes in retromer distribution in NPC1 mouse brains were observed already at the presymptomatic stage (at 4-weeks of age), indicating that the retromer defect occurs early in the course of NPC disease and may contribute to downstream pathological processes. Furthermore, we show that cholesterol depletion in NPC1-null cells and in NPC1 mouse brains reverts retromer dysfunction, suggesting that retromer impairment in NPC is mechanistically dependent on cholesterol accumulation. Thus, we characterized retromer dysfunction in NPC and propose that the rescue of retromer impairment may represent a novel therapeutic approach against NPC

Predicting circulating CA125 levels among healthy premenopausal women

Background: Cancer antigen 125 (CA125) is the most promising ovarian cancer screening biomarker to date. Multiple studies reported CA125 levels vary by personal characteristics, which could inform personalized CA125 thresholds. However, this has not been well described in premenopausal women. Methods: We evaluated predictors of CA125 levels among 815 premenopausal women from the New England Case Control Study (NEC). We developed linear and dichotomous (≥35 U/mL) CA125 prediction models and externally validated an abridged model restricting to available predictors among 473 premenopausal women in the European Prospective Investigation into Cancer and Nutrition Study (EPIC). Results: The final linear CA125 prediction model included age, race, tubal ligation, endometriosis, menstrual phase at blood draw, and fibroids, which explained 7% of the total variance of CA125. The correlation between observed and predicted CA125 levels based on the abridged model (including age, race, and menstrual phase at blood draw) had similar correlation coefficients in NEC (r = 0.22) and in EPIC (r = 0.22). The dichotomous CA125 prediction model included age, tubal ligation, endometriosis, prior personal cancer diagnosis, family history of ovarian cancer, number of miscarriages, menstrual phase at blood draw, and smoking status with AUC of 0.83. The abridged dichotomous model (including age, number of miscarriages, menstrual phase at blood draw, and smoking status) showed similar AUCs in NEC (0.73) and in EPIC (0.78). Conclusions: We identified a combination of factors associated with CA125 levels in premenopausal women. Impact: Our model could be valuable in identifying healthy women likely to have elevated CA125 and consequently improve its specificity for ovarian cancer screening

Development and validation of circulating CA125 prediction models in postmenopausal women.

BACKGROUND: Cancer Antigen 125 (CA125) is currently the best available ovarian cancer screening biomarker. However, CA125 has been limited by low sensitivity and specificity in part due to normal variation between individuals. Personal characteristics that influence CA125 could be used to improve its performance as screening biomarker. METHODS: We developed and validated linear and dichotomous (≥35 U/mL) circulating CA125 prediction models in postmenopausal women without ovarian cancer who participated in one of five large population-based studies: Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO, n = 26,981), European Prospective Investigation into Cancer and Nutrition (EPIC, n = 861), the Nurses' Health Studies (NHS/NHSII, n = 81), and the New England Case Control Study (NEC, n = 923). The prediction models were developed using stepwise regression in PLCO and validated in EPIC, NHS/NHSII and NEC. RESULT: The linear CA125 prediction model, which included age, race, body mass index (BMI), smoking status and duration, parity, hysterectomy, age at menopause, and duration of hormone therapy (HT), explained 5% of the total variance of CA125. The correlation between measured and predicted CA125 was comparable in PLCO testing dataset (r = 0.18) and external validation datasets (r = 0.14). The dichotomous CA125 prediction model included age, race, BMI, smoking status and duration, hysterectomy, time since menopause, and duration of HT with AUC of 0.64 in PLCO and 0.80 in validation dataset. CONCLUSIONS: The linear prediction model explained a small portion of the total variability of CA125, suggesting the need to identify novel predictors of CA125. The dichotomous prediction model showed moderate discriminatory performance which validated well in independent dataset. Our dichotomous model could be valuable in identifying healthy women who may have elevated CA125 levels, which may contribute to reducing false positive tests using CA125 as screening biomarker

Pitfalls in the determination of human acylated ghrelin plasma concentrations using a double antibody enzyme immunometric assay

Objectives: To investigate the effect of hemolysis and protease inhibitors on acylated ghrelin (AG) concentrations measured with a double antibody enzyme immunometric assay that uses an acetylcholinesterase (AChE)-Fab’ conjugate. Design and Methods: Samples were hemolysed or treated with PHMB (phydroxymercuribenzoate), PMSF (phenylmethanesulfonylfluoride) or AEBSF (4-(2-Aminoethyl) benzenesulfonyl fluoride) to prevent AG degradation. Results: Hemolysis decreased AG concentrations. PHMB or PMSF did not affect the assay. The standard curve was abolished by AEBSF but rescued by addition of a washing step prior to the AChE-Fab' conjugate. Conclusions: Hemolysis and AEBSF may affect AG determination.Medicine, Faculty ofPediatrics, Department ofNon UBCReviewedFacult

Optimization of tribological properties of aluminum hybrid composites using Taguchi design

This paper analyses the influence of graphite reinforcement, load and sliding speed with constant sliding distance on tribological behavior of A356 aluminum matrix composites reinforced with 10wt.% silicon carbide and graphite using the Taguchi design. Hybrid composites were produced in the compo-casting process. Tribological tests were performed on a block-on-disc tribometer where the weight percentage of graphite has three variations (0, 3, and 5), as well as load (10 N, 20 N, and 30 N) and sliding speed (0.25m/s, 0.5m/s, and 1m/s), with sliding distance of 300m. The wear of the composite is investigated under dry sliding condition. The specific wear rate was analyzed using Taguchi method with the aim of finding the optimal parameters. By applying analysis of variance, it was determined that the best tribological properties has A356/10SiC/3Gr hybrid composite. It was also found that the greatest impact on specific wear rate has load with the percentage effect of 69.163%, then sliding speed with 14.426% and the interaction between wt.% graphite and load. The dominant wear mechanism is adhesive wear as confirmed by scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS)