Browse

101 - 110 of 642 items :

  • Mathematics x
  • General Mathematics x
  • General Interest x
Clear All

Abstract

Although the information available on pathogenic Escherichia coli is in abundance, foodborne outbreaks are still a major problem. The aim of this study was to describe E. coli strains isolated from cold smoked meat products (37 samples) and sprouted grains (35 samples), to evaluate their virulence potential (vtx1, vtx2; eaeA), to determine serogroups and antibiotic resistance in Latvia. From the isolates tested 66 samples (91.7%) contained none of the virulence genes, 6 samples (8.3%) contained the eaeA gene, and two samples (2.8%) contained eaeA and vtx1 genes. Eleven samples (29.7%) isolated from meat products belonged to serogroups O103, O121, O145, O142, and O26. Six strains contained the eaeA gene, and four of them belonged to serogroup O103, one to O145, and one to O26. Two strains that additional to eaeA gene were also positive to vtx1 belonged to verotoxigenic O26. 31 samples (88.6%) isolated from sprouted grains belonged to serogroups O103 and O121; however, none of the strains contained any of the virulence genes. From strains isolated from meat products 46.0% were resistant to one to three antibiotics, but all isolates from sprouted grains were susceptible. Two strains showed multi-resistance and also contained the mcr-1 gene that encodes resistance to colistin.

Abstract

Porcine circovirus-2 (PCV2) is the primary agent of Postweaning Multisystemic Wasting Syndrome (PMWS), and is associated with Porcine Circovirus Associated Disease, which causes great economic losses in pig breeding. PCV2 infection is distributed worldwide throughout the domestic pig population. There have not been any investigations on the distribution of PCV2 sero-prevalence in the population of pigs in Latvia. However PCV2 is one of main differential infections for many diseases, and therefore it is very variable in clinical presentation of PMWS and other diseases associated with PCV2. The objective of this study was to investigate the seroprevalence of PCV2 in pigs of different-scale farms located in different regions of Latvia. Blood samples of 963 pigs from 58 different-scale farms were examined for the PCV2 antibody from 2006 to 2016. It can be suggested that PCV2 is widespread within the territory of Latvia. Farms with pig number of up to 10 and farms with more than 5000 animals have different levels of biosafety, housing conditions and herd management. Nevertheless, the study showed that the number of PCV2-seropositive animals is similar in all farms (from 70.0% to 79.7%).

Abstract

Colistin is used systemically in critically ill patients for treatment of infections caused by multi-drug resistant (MDR) Gram-negative bacteria, e.g., Acinetobacter baumanii. It is potentially nephro- and neurotoxic. It is recommended to decrease the dose of colistin in case of renal impairment or renal replacement therapies (RRT) but clear recommendations are not available yet. The aim of this retrospective study was to determine colistin use patterns in critically ill patients in Pauls Stradiņš University Hospital. Forty patients were included in this study. The most common indications for colistin were pneumonia associated with mechanical ventilation or sepsis caused by MDR A. baumanii. Median duration of colistin therapy was 11.5 (IQR 7.0; 17.0) days and median cumulative dose was 91.5 (43.0; 150.0) million units (MU). The usual regimen was 9 MU as loading dose and 3 MU three times daily as maintenance dose, but in case of renal impairment and RRT colistin regimens varied a lot between the patients. In 21% (7 from 33) of cases, acute kidney injury (AKI) was observed during colistin therapy (serum creatinine increases more than twice from baseline). All these AKI cases occurred in patients with previously normal renal function and none of the patients in this group needed RRT.

Abstract

Search of new approaches for harmless, non-medication treatment of body dysfunctions is still on the agenda of vet and human practitioners and researchers as well. This study presents evaluation of the effect of “Stress Relief” dietary supplement (SR) on mice behaviour under different acute short-term stress conditions and treatment duration. Five experiments were performed and in each 40 animals were randomly split into four (I–IV) groups, where I and II — non-stressed mice, III and IV — stressed animals, I and III received water with trace mineral solution (TMS), II and IV received water with SR. As stress factors, forced swimming, rodent predator odour or both together were applied. Locomotor activity under normal and stress conditions in Open Field were observed and measured by a SMART video-tracking system. Blood glucose level was measured as well. SR showed a reversal of stress-decreased locomotor activity in all stress models — distance walked increased almost twice (p < 0.0001), central zone crossings and time spent in it were 2–4 times greater than in the control group (p < 0.0001 and p = 0.0002, respectively), and fast movement episodes and maximal speed increased by 50–200%. In addition, complete normalisation of stress-induced elevation of blood glucose level (p < 0.0001) was noted. These results demonstrate for the first time that the effect of “Stress Relief” formula (water additives–minerals processed by know-how way in Vital Force Technology using Dr. Yury Kronn method) can be observed in laboratory animals, and that the effects are significant and repeatable. SR shows fear- and stress-reducing activity, which does not sufficiently differ between 7-, 9-, 14-, 28- and 32-day treatment regimes.

Abstract

Plant interactions in wet tall-herb meadow plant communities were described through dominant and edificator species identification. Five dominant species were identified: Alopecurus pratensis, Filipendula ulmaria, Deschampsia cespitosa, Anthriscus sylvestris, and Angelica sylvestris. The effects of species were studied using ANOVA and correlation analyses. Not all dominants were recognised as edificators. Edificators (Alopecurus pratensis, Filipendula ulmaria, Deschampsia cespitosa, Angelica sylvestris) had a negative effect on the various abundance indicators of associated species: percent cover, number, phytomass, and height. The edificator effects differed significantly in their level and duration and depended on the biomorphs of dominants. The perennial species Alopecurus pratensis, Filipendula ulmaria, and Deschampsia cespitosa were strong constant edificators. Angelica sylvestris, a short-lived monocarpic from the Apiaceae, is a weak seasonal edificator, while Anthriscus sylvestris is not an edificator. Analysis of the life strategies of species showed that competitors are not always edificators (Anthriscus sylvestris), whereas stress-tolerant may show edificator properties (Deschampsia cespitosa). The associated plant species often show positive interactions. Most of the associated species are stress-tolerant and have not an edificator effect.

Abstract

The clinical effects on knee osteoarthritis (OA) symptoms and tissue structure were evaluated after bone marrow-derived mononuclear cell intraarticular injection. A group of 32 patients with 34 knee joints in stage II–III osteoarthritis were treated by intraarticular injection of mononuclear cell suspension. Clinical results were obtained by KOOS (Knee Osteoarthritis Outcome Score) and KSS (Knee Society Score) scores during a 12 months follow-up period. Radiological evaluation was performed using magnetic resonance imaging. A comparison with a control group of 28 patients treated with routinely used three hyaluronic acid intra-articular injections was made. No adverse effects were observed after the bone marrow derived mononuclear cells (BM-MNC) injection. At the end point of the follow up all score results had improved, compared to those at to the starting point. 65% of patients maintained minimal perceptible clinical improvement of the score results. The Whole Organ Magnetic Resonance Imaging Score showed improvement from 44.31 to 42.93 points (p < 0.05) during a 6–7 month period. Comparing score results to the control group, a statistically significant (p < 0.05) improvement in the KOOS pain subscale score at the 6 and 12 months was observed in the mononuclear cell group. BM-MNC injection leads to a decrease of knee OA symptoms and slows changes in structure of the degenerative joint tissue.

Abstract

The Förster Resonance Energy Transfer (FRET) method has wide application in modern science for studying protein–protein interactions and conformational changes. FRET allows to assess molecular interactions by measuring energy transfer between acceptor and donor fluorophores coupled to the molecule(s) of interest. The method demands high precision in experimental design, experimental settings and correct data interpretation. Therefore, we tested several parameters to estimate FRET measurement accuracy in our Nikon wide-field fluorescence FRET system. The experiments were performed in a HEK-293 cell line transfected with DNA constructs expressing Calcium Release-Activated Channel (CRAC) subunits STIM1 and ORAI1 coupled to donor fluorophore Cyan Fluorescent Protein (CFP) and acceptor fluorophore Yellow Fluorescent Protein (YFP), respectively. Exposure time and approach of data analysis varied throughout experiments in order to optimise FRET data quality. Dependence of FRETeff values on measurement quality and donor/acceptor fluorophore ratio in the cells was estimated. We demonstrated that, using the wide-field fluorescence FRET system, minimising the exposure of fluorophores before measurement using neutral density (ND) filters considerably minimises undesirable photo-bleaching of the fluorophores. There was a strong correlation between the CFP/YFP ratio in the cells and the observed FRET level, suggesting that only cells with certain donor/acceptor ratio might be comparable. We also showed impact of FRET measurement quality, defined as accordance of FRET pixels to Gaussian distribution, on FRET artefacts. Knowledge obtained during our experiments may be important for approbating similar wide-field fluorescence FRET systems to study two separate molecule interactions and for understanding the correct setup of the experiments and data interpretation.

Abstract

Seasonal changes of abiotic factors and their influence on parasite occurrence have repeatedly been studied. Most of the studies have been conducted to evaluate the effect of water physicochemical parameters on changes in the intensity of infection, prevalence and component community of a number of parasite species. However, insufficient attention has been paid to the link between water quality parameters and spatial niche size of ectoparasites. The distribution of ectoparasite species on perch (Perca fluviatilis L.) was studied to establish whether seasonal changes of water quality parameters are associated with ectoparasite spatial niche size. The concentration of phosphates (PO4 3−), nitrates (NO 3), sulphates (SO4 2−) and dissolved oxygen (DO) in the water of Lake Sila (Latvia) was measured every month throughout the year and recorded all ectoparasites on perch. Zero-inflated mixed models were used to evaluate which of the water parameters influence the spatial niche size of ectoparasites. Our findings showed that spatial niche size of some ectoparasite species is affected by a set of water quality parameters and that this effect is negative. The spatial niche size of Anodonta cygnea was negatively associated with phosphate, nitrate, sulphate and dissolved oxygen concentration. The spatial niche size of Ancyrocephalus percae was negatively associated with sulphate, and the spatial niche size of Ergasilus sieboldi was negatively associated with nitrate concentration.

Abstract

In the brackish ecosystem of the Gulf of Riga, the calanoid copepod Eurytemora affinis is a key species, but recently a new non-indigenous species Eurytemora carolleeae was discovered in the region. In the present study, we aimed to validate the presence of E. carolleeae in the southern part of the Gulf of Riga five years after its first discovery. The study area is the closest region to the Rīga harbour — the main source of non-indigenous species arrival in the Gulf. Recent studies have predicted the possible potential of E. carolleeae invasion due to its physiological plasticity. Male and female specimens of Eurytemora were collected in spring, summer, and autumn of 2013, and analysed based on three morphological indicators. Despite the higher reproduction rate of E. carolleeae, this intrusive species does not seem to have succeeded in establishing during the five-year period after its first discovery in the Gulf of Riga, and hence does not present a threat to the native E. affinis population in the study area.