47 research outputs found

    The recovery of tin from slags by gaseous reduction and fuming

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    Imperial Users onl

    On the constant term of the minimal polynomial of cos (2 pi/n) over Q

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    The algebraic numbers cos (2 pi/n) and 2 cos (pi/n) play an important role in the theory of discrete groups and has many applications because of their relation with Chebycheff polynomials. There are some partial results in literature for the minimal polynomial of the latter number over rationals until 2012 when a complete solution was given in [5]. In this paper we determine the constant term of the minimal polynomial of cos(2 pi/n) over Q by a new method

    Vector-borne pathogens of zoonotic concern in hunting dogs of southern Italy

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    Dogs are commonly exposed to vector-borne pathogens (VBPs), yet few data are available on hunting dogs, which are often at high risk of infection due to their involvement in field activities. To investigate the occurrence of VBPs and evaluate the relative performance of different diagnostic tools, blood and serum samples were collected from hunting dogs (n = 1,433) in rural areas of southern Italy. All samples were tested by Knott's technique for filarioids, serologically (SNAP® 4Dx® Plus) for Anaplasma spp., Borrelia burgdorferi sensu lato, Dirofilaria immitis and Ehrlichia spp. and molecularly (qPCR) for all except B. burgdorferi of the above pathogens plus Babesia spp. and Leishmania infantum. Logistic regression was run to evaluate the statistical associations between the risk of VBP infection and independent variables (such as geographic area of provenience, age class and sex) and K-Cohen formula for assessing the concordance among diagnostic tests. Overall, out of 321 dogs (22.4%) positive to at least one VBP, 28 (1.9%) were infected by filarial species at the Knott's technique. In particular, Acanthocheilonema reconditum was the most prevalent (1.6%), followed by D. immitis (0.2%) and Dirofilaria repens (0.1%). One hundred forty (9.8%) and 231 (16.1%) dogs scored positive to VBPs by serological and molecular methods, respectively. The most prevalent pathogens detected were Ehrlichia spp. (7.3%) with SNAP® 4Dx® Plus, and A. reconditum (7.7%) by qPCR. Statistics revealed a significant association (p < 0.001) between A. reconditum infestation and both Ehrlichia spp. seropositivity and geographical origin of dogs. An agreement of 99.9%, 94.0% and 95.7% for Knott - SNAP® 4Dx® Plus, Knott - qPCR and SNAP® 4Dx® Plus - qPCR for D. immitis was found, respectively. Data demonstrate a high prevalence of VBPs in hunting dogs, indicating that this group of animals is largely exposed to several arthropod vector species and suggesting the transmission risk of pathogens to humans in rural areas of southern Italy. A multi-diagnostic approach and a deeper cooperation among healthcare and stakeholders are required to prevent VBP infections to animals and humans

    Prvi potvrđeni klinički slučaj infekcije psa vrstom Anaplasma platys u Srbiji

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    In September 2018, a four-month-old dog with fever and petechial bleeding came to the internal clinic at the Faculty of Veterinary Medicine University of Belgrade. On hematology analysis, thrombocytopenia and mild anemia were observed. Examination of the blood smear revealed platelet inclusions. The commercial serology test was positive for Anaplasma spp. The dog was treated with doxycycline for 14 days, and after 48 hours from the beginning of the treatment, the symptoms subsided. PCR analysis and sequencing confirmed infection with A. platys.U septembru 2018. godine, štene staro četiri meseca, sa znacima groznice i petehijalnim krvarenjem, je došlo u ambulantu Klinike za male životinje Fakulteta veterinarske medicine Univerziteta u Beogradu. Hematološka analiza je pokazala trombocitopeniju i blagu anemiju. Pregledom krvnog razmaza ustanovljene su inkluzije u trombocitima. Komercijalni serološki test je pokazao prisustvo antitela protiv Anaplasma spp. Sprovedena je terapija doksiciklinom u trajanju od 14 dana, a posle 48 sati od početka terapije znaci bolesti su se povukli. PCR analizom i senkvencioniranjem je potvrđeno prisustvo Anaplasma platys

    Evaluation of Wuchereria bancrofti GST as a Vaccine Candidate for Lymphatic Filariasis

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    Lymphatic parasites survive for years in a complex immune environment by adopting various strategies of immune modulation, which includes counteracting the oxidative free radical damage caused by the host. We now know that the filarial parasites secrete antioxidant enzymes. Among these, the glutathione-S-transferases (GSTs) have the potent ability to effectively neutralize cytotoxic products arising from reactive oxygen species (ROS) that attack cell membranes. Thus, GSTs have the potential to protect the parasite against host oxidative stress. GSTs of several helminthes, including schistosomes, fasciola and the filarial parasite Seteria cervi, are also involved in inducing protective immunity in the host. The schistosome 28 kDa GST has been successfully developed into a vaccine and is currently in Phase II clinical trials. Thus, GST appears to be a potential target for vaccine development. Therefore, in the present study, we cloned W. bancrofti GST, and expressed and purified the recombinant protein. Immunization and challenge experiments showed that 61% of protection could be achieved against B. malayi infections in a jird model. In vitro studies confirm that the anti-WbGST antibodies participate in the killing of B. malayi L3 through an ADCC mechanism and enzymatic activity of WbGST appears to be critical for this larvicidal function

    Association of acute Babesia canis infection and serum lipid, lipoprotein, and apoprotein concentrations in dogs

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    Background Babesia canis infection induces a marked acute phase response (APR) that might be associated with alteration in lipid and lipoprotein metabolism and disease prognosis. Hypothesis Dogs with B. canis-induced APR develop dyslipidemia with altered lipoprotein concentration and morphology. Animals Twenty-nine client-owned dogs with acute B. canis infection and 10 clinically healthy control dogs. Methods Observational cross-sectional study. Serum amyloid A (SAA) was measured using ELISA. Cholesterol, phospholipids, and triglycerides were determined biochemically. Lipoproteins were separated using agarose gel electrophoresis. Lipoprotein diameter was assessed by polyacrylamide gradient gel electrophoresis; correlation with ApoA-1 (radioimmunoassay) and SAA was determined. Results Dogs with B. canis infection had a marked APR (median SAA, 168.3 mu g/mL; range, 98.1-716.2 mu g/mL) compared with controls (3.2 mu g/mL, 2.0-4.2 mu g/mL) (P < .001). Dogs with B. canis infection had significantly lower median cholesterol (4.79 mmol/L, 1.89-7.64 mmol/L versus 6.15 mmol/L, 4.2-7.4 mmol/L) (P = .02), phospholipid (4.64 mmol/L, 2.6-6.6 mmol/L versus 5.72 mmol/L, 4.68-7.0 mmol/L) (P = .02), and alpha-lipoproteins (77.5%, 27.7%-93.5% versus 89.2%, 75.1%-93.5%) (P = .04), and higher ApoA-1 (1.36 U, 0.8-2.56 U versus 0.95 U, 0.73-1.54 U) concentrations (P = .02). Serum amyloid A correlated with high-density lipoproteins (HDLs) diameter (rho = .43; P = .03) and ApoA-1 (rho = .63, P < .001). Conclusions and Clinical Importance Major changes associated with B. canis-induced APR in dogs are related to concentration, composition, and morphology of HDL particles pointing to an altered reverse cholesterol transport. Parallel ApoA-1 and SAA concentration increase is a unique still unexplained pathophysiological finding

    A Comparison of Copromicroscopic and Molecular Methods for the Diagnosis of Cat Aelurostrongylosis

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    The gold standard method for the diagnosis of cat aelurostrongylosis is the detection of Aelurostrongylus abstrusus first stage larvae with the Baermann's examination. Nevertheless, molecular assays have shown higher diagnostic performances compared to copromicroscopy. This study evaluated the usefulness of an A. abstrusus species-specific PCR on different biological samples collected in clinical settings from 100 privately-owned cats in Italy (n. 60) and Greece (n. 40). A fecal sample was collected from each animal and a pharyngeal swab was also obtained for cats from Italy. All stool samples were subjected to flotation and Baermann's test. The cats were categorized in three groups based on the results of copromicroscopy, i.e., Group A (n. 50 cats with A. abstrusus infection regardless of positivity for other helminths), Group B (n. 25 cats negative for A. abstrusus but positive for at least one of any other helminth), Group C (n. 25 cats negative for any helminth). DNA was extracted from individual aliquots of feces, flotation supernatant, Baermann's sediment and the pharyngeal swab and then subjected to a PCR specific for A. abstrusus. At least one fecal aliquot or the pharyngeal swab scored positive by the A. abstrusus-specific PCR for 48/50 (96%) cats enrolled in Group A; in particular, 38/50 (76%), 35/50 (70%), 41/50 (82%) and 21/25 (84%) DNA extracts from feces, flotation supernatant, Baermann's sediment and pharyngeal swabs were positive by PCR. These results confirm that molecular tools are highly sensitive and specific and indicate that pharyngeal swabs are the most suitable sample for molecular analysis in clinical settings

    Investigação sorológica de espécies de Ehrlichia em cães, equinos e humanos de um assentamento rural do sul do Brasil

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    Objetivou-se determinar a soroprevalência de Ehrlichia spp. e os fatores de risco associados a exposição em uma população restrita de cães, cavalos e humanos altamente expostos a picadas de carrapatos em um assentamento rural brasileiro utilizando um teste comercial de ELISA rápido e dois testes de imunofluorescência indireta (IFI) com antígenos brutos de E. canis e E. chaffeensis. Amostras de soro de 132 cães, 16 cavalos e 100 humanos foram utilizadas. Cinquenta e seis/132 (42,4%) cães foram soropositivos para E. canis. Cães &gt; um ano apresentaram mais chance de serem soropositivos para E. canis do que cães ≤ um ano (p =0,0051). Dez/16 (62,5%) e 8/16 (50%) cavalos foram soropositivos pelo ELISA comercial e IFI, respectivamente. Cinco/100 (5%) humanos foramsoropositivos para E. canis e E. chaffeensis. Rhipicephalus sanguineus (n= 291, 97,98%) nos cães e A. cajennense (n = 25, 96,15%) nos cavalos foram os carrapatos mais encontrados. Concluindo, anticorpos anti-Ehrlichia spp. foram encontrados em cavalos; entretanto, a ausência de uma caracterização molecular impede qualquer conclusão sobre agente envolvido. Além disso, a alta soroprevalência de E. canis em cães e a evidência de anticorpos anti-Ehrlichia sp. em humanos, sugere que os casos de erliquiose humana no Brasil possam ser causados por E. canis ou outra espécie intimamente relacionada.The aims of this study were to determine the seroprevalence of Ehrlichia spp. and risk factors for exposure in a restricted population of dogs, horses, and humans highly exposed to tick bites in a Brazilian rural settlement using a commercial ELISA rapid test and two indirect immunofluorescent assays (IFA) with E. canis and E. chaffeensis crude antigens. Serum samples from 132 dogs, 16 horses and 100 humans were used. Fifty-six out of 132 (42.4%) dogs were seropositive for E. canis. Dogs &gt; one year were more likely to be seropositive for E. canis than dogs ≤ one year (p = 0.0051). Ten/16 (62.5%) and 8/16 (50%) horses were seropositive by the commercial ELISA and IFA, respectively. Five out of 100 (5%) humans were seropositive for E. canis and E. chaffeensis. Rhipicephalus sanguineus (n = 291, 97.98%) on dogs and Amblyomma cajennense (n = 25, 96.15%) on horses were the most common ticks found. In conclusion, anti-Ehrlichia spp. antibodies were found in horses; however, the lack of a molecular characterization precludes any conclusion regarding the agent involved. Additionally, the higher seroprevalence of E. canis in dogs and the evidence of anti-Ehrlichia spp. antibodies in humans suggest that human cases of ehrlichiosis in Brazil might be caused by E. canis, or other closely related species

    Biochemical Characterization and Evaluation of a Brugia malayi Small Heat Shock Protein as a Vaccine against Lymphatic Filariasis

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    Filarial nematodes enjoy one of the longest life spans of any human pathogen due to effective immune evasion strategies developed by the parasite. Among the various immune evasion strategies exhibited by the parasite, Interleukin 10 (IL-10) productions and IL-10 mediated immune suppression has significant negative impact on the host immune system. Recently, we identified a small heat shock protein expressed by Brugia malayi (BmHsp12.6) that can bind to soluble human IL-10 receptor alpha (IL-10R) and activate IL-10 mediated effects in cell lines. In this study we show that the IL-10R binding region of BmHsp12.6 is localized to its N-terminal region. This region has significant sequence similarity to the receptor binding region of human IL-10. In vitro studies confirm that the N-terminal region of BmHsp12.6 (N-BmHsp12.6) has IL-10 like activity and the region containing the alpha crystalline domain and C-terminus of BmHsp12.6 (BmHsp12.6αc) has no IL-10 like activity. However, BmHsp12.6αc contains B cell, T cell and CTL epitopes. Members of the sHSP families are excellent vaccine candidates. Evaluation of sera samples from putatively immune endemic normal (EN) subjects showed IgG1 and IgG3 antibodies against BmHsp12.6αc and these antibodies were involved in the ADCC mediated protection. Subsequent vaccination trials with BmHsp12.6αc in a mouse model using a heterologous prime boost approach showed that 83% protection can be achieved against B. malayi L3 challenge. Results presented in this study thus show that the N-BmHsp12.6 subunit of BmHsp12.6 has immunoregulatory function, whereas, the BmHsp12.6αc subunit of BmHsp12.6 has significant vaccine potential
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