RESUMO
We have studied the mode of action of the insecticide spirotetramat in the nematode Caenorhabditis elegans. A combination of symptomology, forward genetics and genome editing show that spirotetramat acts on acetyl-CoA carboxylase (ACC) in C. elegans, as it does in insects. We found C. elegans embryos exposed to spirotetramat show a cell division defect which closely resembles the phenotype of loss-of-function mutations in the gene pod-2, which encodes ACC. We then identified two mutations in the carboxyl transferase domain of pod-2 (ACC) which confer resistance and were confirmed using CRISPR/Cas9. One of these mutations substitutes an invertebrate-specific amino acid with one ubiquitous in other taxa; this residue may, therefore, be a determinant of the selectivity of spirotetramat for invertebrates. Such a mutation may also be the target of selection for resistance in the field. Our study is a further demonstration of the utility of C. elegans in studying bioactive chemicals.
Assuntos
Carboxil e Carbamoil Transferases , Inseticidas , Acetil-CoA Carboxilase , Animais , Caenorhabditis elegans , MutaçãoRESUMO
BACKGROUND: Complex Regional Pain Syndrome (CRPS) is a disabling disease that is sometimes difficult to treat. Although spinal cord stimulation (SCS) can reduce pain in most patients with CRPS, some do not achieve the desired reduction in pain. Moreover, the pain reduction can diminish over time even after an initially successful period of SCS. Pain reduction can be regained by increasing the SCS frequency, but this has not been investigated in a prospective trial. This study compares pain reduction using five SCS frequencies (standard 40 Hz, 500 Hz, 1200 Hz, burst and placebo stimulation) in patients with CRPS to determine which of the modalities is most effective. DESIGN: All patients with a confirmed CRPS diagnosis that have unsuccessfully tried all other therapies and are eligible for SCS, can enroll in this trial (primary implantation group). CRPS patients that already receive SCS therapy, or those previously treated with SCS but with loss of therapeutic effect over time, can also participate (re-implantation group). Once all inclusion criteria are met and written informed consent obtained, patients will undergo a baseline assessment (T0). A 2-week trial with SCS is performed and, if successful, a rechargeable internal pulse generator (IPG) is implanted. For the following 3 months the patient will have standard 40 Hz stimulation therapy before a follow-up assessment (T1) is performed. Those who have completed the T1 assessment will enroll in a 10-week crossover period in which the five SCS frequencies are tested in five periods, each frequency lasting for 2 weeks. At the end of the crossover period, the patient will choose which frequency is to be used for stimulation for an additional 3 months, until the T2 assessment. DISCUSSION: Currently no trials are available that systematically investigate the importance of variation in frequency during SCS in patients with CRPS. Data from this trial will provide better insight as to whether SCS with a higher frequency, or with burst stimulation, results in more effective pain relief. TRIAL REGISTRATION: Current Controlled Trials ISRCTN36655259.
Assuntos
Síndromes da Dor Regional Complexa/terapia , Estimulação da Medula Espinal/métodos , Absenteísmo , Analgésicos/economia , Analgésicos/uso terapêutico , Terapia Combinada , Síndromes da Dor Regional Complexa/tratamento farmacológico , Síndromes da Dor Regional Complexa/economia , Síndromes da Dor Regional Complexa/fisiopatologia , Estudos Cross-Over , Método Duplo-Cego , Gastos em Saúde , Humanos , Dinamômetro de Força Muscular , Medição da Dor , Percepção da Dor , Limiar da Dor , Parestesia/fisiopatologia , Parestesia/terapia , Estudos Prospectivos , Temperatura Cutânea , Estimulação da Medula Espinal/economia , Termografia , Resultado do TratamentoRESUMO
Late in 2007, veterinary, medical and anthropological professionals from Europe and Africa met in a 2-day workshop in Pretoria, South Africa, to evaluate the burden, surveillance and control of zoonotic tuberculosis and brucellosis in sub-Saharan Africa. Keynote presentations reviewed the burden of these diseases on human and livestock health, the existing diagnostic tools, and the available control methods. These presentations were followed by group discussions and the formulation of recommendations. The presence of Mycobacterium bovis and Brucella spp. in livestock was considered to be a serious threat to public health, since livestock and animal products are the only source of such infections in human beings. The impact of these pathogens on human health appears to be relatively marginal, however, when compared with Mycobacterium tuberculosis infections and drug resistance, HIV and malaria. Appropriate diagnostic tools are needed to improve the detection of M. bovis and Brucella spp. in humans. In livestock, the 'test-and-slaughter' approach and the pasteurization of milk, which have been used successfully in industrialized countries, might not be the optimal control tools in Africa. Control strategies should fit the needs and perceptions of local communities. Improved intersectoral and international collaboration in surveillance, diagnosis and control, and in the education of medical and veterinary personnel, are advocated.
Assuntos
Brucelose , Tuberculose , Zoonoses , África Subsaariana/epidemiologia , Animais , Animais Domésticos , Brucelose/diagnóstico , Brucelose/epidemiologia , Brucelose/prevenção & controle , Humanos , Saúde Pública , Tuberculose/diagnóstico , Tuberculose/epidemiologia , Tuberculose/prevenção & controle , Zoonoses/epidemiologia , Zoonoses/transmissãoRESUMO
Veterinary education commenced in South Africa in 1920 at the Onderstepoort Veterinary Institute in South Africa in association with the Transvaal University College, now the University of Pretoria. Sir Arnold Theiler, Director of Veterinary Research and Education, was the first Dean. Today there are 46 veterinary training institutions in Africa of which 21 are in sub-Saharan Africa. Veterinary services are indispensable to the sustained health and wellbeing of animals and humans, and agricultural economies of countries worldwide. Veterinary education, postgraduate training, and research, and adequate numbers of veterinarians, are essential to satisfy the millennium development goals, the objectives of NEPAD and the African Union, and the agreements regulating international trade. The relevance of the veterinary profession internationally is currently subject to profound scrutiny. Its contributions are assessed against major environmental, demographic, political, disease, technological and economic needs. The scope of veterinary training in future will have to emphasise veterinary public health, food safety, emerging diseases, international trade, bioterrorism, and biomedical research, within the context of a one-health system focusing on the interface between wildlife, domesticated animals, humans, and their environment. Within the context of time available, it would mean reducing the time allocated to training in the field of companion animals. A brief history and scope of veterinary education; current international trends in veterinary education and provisioning; and some perspectives on future veterinary training and initiatives applicable to Africa are provided.
Assuntos
Educação em Veterinária/tendências , Saúde Pública , Medicina Veterinária/tendências , África , Animais , Educação em Veterinária/normas , Previsões , Humanos , Internacionalidade , Pesquisa/tendências , Medicina Veterinária/normasRESUMO
Essentials Heat shock protein 47 (HSP47), a collagen specific chaperone is present on the platelet surface. Collagen mediated platelet function was reduced following blockade or deletion of HSP47. GPVI receptor regulated signalling was reduced in HSP47 deficient platelets. Platelet HSP47 tethers to exposed collagen thus modulating thrombosis and hemostasis. SUMMARY: Objective Heat shock protein 47 (HSP47) is an intracellular chaperone protein that is vital for collagen biosynthesis in collagen secreting cells. This protein has also been shown to be present on the surface of platelets. Given the importance of collagen and its interactions with platelets in triggering hemostasis and thrombosis, in this study we sought to characterize the role of HSP47 in these cells. Methods and Results The deletion of HSP47 in mouse platelets or its inhibition in human platelets reduced their function in response to collagen and the GPVI agonist (CRP-XL), but responses to thrombin were unaltered. In the absence of functional HSP47, the interaction of collagen with platelets was reduced, and this was associated with reduced GPVI-collagen binding, signalling and platelet activation. Thrombus formation on collagen, under arterial flow conditions, was also decreased following the inhibition or deletion of HSP47, in the presence or absence of eptifibatide, consistent with a role for HSP47 in enhancing platelet adhesion to collagen. Platelet adhesion under flow to von Willebrand factor was unaltered following HSP47 inhibition. Laser-induced thrombosis in cremaster muscle arterioles was reduced and bleeding time was prolonged in HSP47-deficient mice or following inhibition of HSP47. Conclusions Our study demonstrates the presence of HSP47 on the platelet surface, where it interacts with collagen, stabilizes platelet adhesion and increases collagen-mediated signalling and therefore thrombus formation and hemostasis.
Assuntos
Plaquetas/metabolismo , Proteínas de Transporte/sangue , Colágeno/sangue , Proteínas de Choque Térmico HSP70/sangue , Hemostasia , Ativação Plaquetária , Trombose/sangue , Animais , Plaquetas/efeitos dos fármacos , Sinalização do Cálcio , Proteínas de Transporte/antagonistas & inibidores , Proteínas de Transporte/genética , Modelos Animais de Doenças , Proteínas de Choque Térmico HSP70/antagonistas & inibidores , Proteínas de Choque Térmico HSP70/deficiência , Proteínas de Choque Térmico HSP70/genética , Hemostasia/efeitos dos fármacos , Humanos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas Mitocondriais , Ativação Plaquetária/efeitos dos fármacos , Adesividade Plaquetária , Inibidores da Agregação Plaquetária/farmacologia , Glicoproteínas da Membrana de Plaquetas/metabolismo , Ligação Proteica , Trombose/genética , Trombose/prevenção & controleRESUMO
BACKGROUND: Conventional tonic spinal cord stimulation (SCS) is an effective treatment for patients with therapy-resistant complex regional pain syndrome (CRPS). Although the therapeutic effect of SCS can diminish over time due to tolerance, pain control can be regained by changing the pulse width and the amplitude and/or by increasing the stimulation frequency. This multicentre, double-blind, randomized and placebo-controlled crossover trial was conducted to investigate whether more effective pain reduction is achieved with different frequencies (trial registration, current controlled trials, ISRCTN 36655259). METHODS: The investigated settings are as follows: standard 40, 500, 1200 Hz, burst and placebo stimulation. All five were programmed in random order during the 10-week crossover period (2 weeks/setting). The primary outcome parameters were scores on the visual analogue scale (VAS), McGill Pain Questionnaire (MPQ) and the Global Perceived Effect (GPE); at the end of the crossover period, patients decided which SCS setting they preferred. A linear mixed models analysis was performed in 29 patients who completed the crossover trial. RESULTS: Significant pain reduction and GPE satisfaction was achieved with four SCS settings compared with placebo stimulation, and these four settings did not differ significantly from each other. Standard stimulation was preferred by 48% of the patients, while 52% preferred non-standard stimulation. Other than pain reduction, factors such as user-friendliness, comfort and recharging time may have influenced the patient's final decision for the preferred stimulation setting. CONCLUSIONS: Apparently, for various reasons, patients have a preference for different SCS setting. Therefore, future neuromodulation should aim to implement customized individual patient care by incorporating all stimulation options in one device. SIGNIFICANCE: This study demonstrates that standard frequency SCS is an effective therapy for patients with CRPS. However, it also demonstrates that patients can often gain better pain reduction with non-standard frequencies of SCS. Furthermore, it shows that the preferred stimulation setting is not solely driven by the amount of pain reduction, but is also influenced by which stimulation setting feels most comfortable and provides the best user-friendliness. Therefore, we strive to maximize the therapeutic effects of SCS in as many patients as possible. This can be achieved with customized individual patient care by incorporating the various frequencies and waveforms into one single device.
Assuntos
Síndromes da Dor Regional Complexa/terapia , Estimulação da Medula Espinal/métodos , Adulto , Estudos Cross-Over , Método Duplo-Cego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Manejo da Dor , Medição da Dor , Estimulação da Medula Espinal/efeitos adversos , Estimulação da Medula Espinal/estatística & dados numéricos , Resultado do TratamentoRESUMO
Essentials peroxisome proliferator-activated receptor γ (PPARγ) agonists inhibit platelet function. PPARγ agonists negatively regulate outside-in signaling via integrin αIIbß3. PPARγ agonists disrupt the interaction of Gα13 with integrin ß3. This is attributed to an upregulation of protein kinase A activity. SUMMARY: Background Agonists for the peroxisome proliferator-activated receptor (PPARγ) have been shown to have inhibitory effects on platelet activity following stimulation by GPVI and GPCR agonists. Objectives Profound effects on thrombus formation led us to suspect a role for PPARγ agonists in the regulation of integrin αIIbß3 mediated signaling. Both GPVI and GPCR signaling pathways lead to αIIbß3 activation, and signaling through αIIbß3 plays a critical role in platelet function and normal hemostasis. Methods The effects of PPARγ agonists on the regulation of αIIbß3 outside-in signaling was determined by monitoring the ability of platelets to adhere and spread on fibrinogen and undergo clot retraction. Effects on signaling components downstream of αIIbß3 activation were also determined following adhesion to fibrinogen by Western blotting. Results Treatment of platelets with PPARγ agonists inhibited platelet adhesion and spreading on fibrinogen and diminished clot retraction. A reduction in phosphorylation of several components of αIIbß3 signaling, including the integrin ß3 subunit, Syk, PLCγ2, focal adhesion kinase (FAK) and Akt, was also observed as a result of reduced interaction of the integrin ß3 subunit with Gα13. Studies of VASP phosphorylation revealed that this was because of an increase in PKA activity following treatment with PPARγ receptor agonists. Conclusions This study provides further evidence for antiplatelet actions of PPARγ agonists, identifies a negative regulatory role for PPARγ agonists in the control of integrin αIIbß3 outside-in signaling, and provides a molecular basis by which the PPARγ agonists negatively regulate platelet activation and thrombus formation.
Assuntos
Plaquetas/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , PPAR gama/agonistas , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/metabolismo , Animais , Bovinos , Adesão Celular , Retração do Coágulo , Colágeno/química , Fibrinogênio/química , Subunidades alfa G12-G13 de Proteínas de Ligação ao GTP/metabolismo , Hemostasia , Humanos , Integrina beta3/metabolismo , Fosforilação , Ativação Plaquetária/efeitos dos fármacos , Adesividade Plaquetária , Agregação Plaquetária/efeitos dos fármacos , Testes de Função Plaquetária , Glicoproteínas da Membrana de Plaquetas/metabolismo , Transdução de Sinais , Regulação para CimaRESUMO
An infection model for Mycobacterium bovis in African buffaloes, Syncerus caffer, was developed, using the intratonsilar route of inoculation. Two groups of 11 buffaloes each, aged approximately 18 months, were infected with either 3.2 x 10(2) cfu (low dose) or 3 x 10(4) cfu (high dose) of M. bovis strain isolated from a buffalo. A control group of six buffaloes received saline via the same route. The infection status was monitored in vivo using the comparative intradermal tuberculin test, and in vitro by the modified interferon-gamma assay. All buffaloes were euthanazed 22 weeks post infection and lesion development was assessed by macroscopic examination, culture and histopathology. It was found that the high dose caused macroscopic lesions in nine out of 11 buffaloes. Mycobacterium bovis was isolated from all buffaloes in the high-dose group and from six out of 11 in the low-dose group.
Assuntos
Búfalos/microbiologia , Modelos Animais de Doenças , Mycobacterium bovis/patogenicidade , Tuberculose Bovina/microbiologia , Animais , Bovinos , Contagem de Colônia Microbiana/veterinária , Interferon gama/sangue , Mycobacterium bovis/imunologia , Tonsila Palatina/microbiologia , Distribuição Aleatória , Especificidade da Espécie , Teste Tuberculínico/veterináriaRESUMO
Vervet monkeys ( Ceropithecus aethiops pygerethrus ) were placed on semipurified diets containing 14% fat of which 3.2 or 6.0% was present as trans-unsaturated fatty acid (t-FA). Two groups were fed the high and low levels of t-FA for a year and two others were fed t-FA for 6 months and then returned to the control diet for 6 months more. One other group was fed the control diet for a year. The control diet contained 14% fat which was a mixture of 72% olive oil and 28% corn oil. There were no significant differences in weight gain. Monkeys fed 6% t-FA or control diets for one year had lowest liver weights. Serum cholesterol and triglycerides in monkeys fed 3.2% t-FA for one year were 134 and 55 mg/dl, respectively; in monkeys returned to control diet after 6 months on 6% t-FA the values were 146 and 50 g/dl. Serum and triglyceride levels for the other 3 groups were 166 +/- 2 and 70 +/- 2 mg/dl. Liver cholesterol levels ranged from 4.0 mg/g (3.2% t-FA) to 4.7 mg/g (control) and 4.8 mg/g (6% t-FA). Lecithin:cholesterol acyltransferase (LCAT) activity was 59.0 microM/h for controls and ranged from 52.4 microM/h (3.2% t-FA) to 73.4 microM/h (6% t-FA). Cholesterol synthesis by liver slices was not affected by diet when the substrate was acetate. When mevalonate was used, the monkeys fed either level of t-FA for 12 months exhibited greatly reduced (about 80%) cholesterogenesis. The levels of t-FA in serum and liver reflected the amount in the diet. After being returned to control diet levels of t-FA in serum and liver of monkeys (fed 3.2% t-FA) fell by 97 and 94%, respectively, and those in serum and liver of monkeys fed 6% t-FA fell by 65 and 91%. There were no significant differences in aortic atherosclerosis or arteriosclerosis.(ABSTRACT TRUNCATED AT 400 WORDS)
Assuntos
Arteriosclerose/metabolismo , Ácidos Graxos Insaturados/farmacologia , Animais , Peso Corporal , Colesterol/biossíntese , Feminino , Haplorrinos , Fígado/análise , Fígado/enzimologia , Masculino , Fatores Sexuais , Triglicerídeos/sangueRESUMO
Vervet monkeys (Cercopithecus aethiops pygerethrus) were fed cholesterol-free, semipurified diets containing 40% sucrose, 25% casein, 15% cellulose and 14% peanut oil (PNO), randomized peanut oil (RPNO) or corn oil (CO). After 4 months, serum cholesterol and triglyceride levels, serum lecithin-cholesterol acyl transferase (LCAT) activity and plasma lipoprotein lipase (LPL) activity were similar in all groups. Livers of monkeys fed CO converted 156% more acetate and 24% more mevalonate to cholesterol than those of monkeys fed RPNO. Cholesterogenesis in RPNO-fed monkeys was enhanced compared to PNO (68% from acetate; 62% from mevalonate). Incidence of atherosclerosis was 33% in monkeys fed RPNO, 80% in those fed CO and 90% in those fed PNO. Extent of sudanophilia was lowest in aortas of monkeys fed RPNO. Incidence of arteriosclerosis was 40% in monkeys fed CO, 56% in those fed RPNO and 70% in those fed PNO. Extent of aortic surface showing arteriosclerosis was highest in monkeys fed RPNO.
Assuntos
Arteriosclerose/etiologia , Colesterol/biossíntese , Gorduras na Dieta/efeitos adversos , Metabolismo dos Lipídeos , Óleos/efeitos adversos , Óleos de Plantas , Animais , Aorta/análise , Chlorocebus aethiops , Colesterol/sangue , Óleo de Milho , Fígado/análise , Óleo de Amendoim , Fosfatidilcolinas/sangue , Distribuição Aleatória , Triglicerídeos/sangueRESUMO
Adding less than 0.5% w/w of culture material of strain MRC 826 of the fungus Fusarium moniliforme to a carbohydrate diet low in fat resulted in an atherogenic plasma lipid profile in a non-human primate. Simultaneously increased plasma fibrinogen and activity of blood coagulation factor VII could enhance atherogenesis. This unique potential for promotion of atherosclerosis was probably secondary to chronic hepatotoxicity as indicated by liver fibrosis and elevated cholesterol, albumin and the enzymes AST, ALT, LD, GGT and ALP in serum. The cholesterol and enzymes responded in proportion to the calculated doses of fumonisin mycotoxins in the F. moniliforme MRC 826 cultures. Fumonisins are water soluble and heat stable. Thrombotic, hepatotoxic, carcinogenic and cerebral effects of MRC 826 culture material and fumonisins are well known in non-primates. The estimated fumonisin concentrations tested fall within a range due to natural contamination of human foods. The results suggest that all maize grain products should be analysed for fumonisins.
Assuntos
Arteriosclerose/etiologia , Carboidratos da Dieta/administração & dosagem , Fusarium , Animais , Chlorocebus aethiops , Colesterol/sangue , Gorduras na Dieta/administração & dosagem , Feminino , Fibrinogênio/análise , Fusarium/metabolismo , Hemostasia , Imunoglobulinas/análise , Fígado/enzimologia , Fígado/metabolismo , Fígado/patologia , Masculino , Micotoxinas/biossíntese , Micotoxinas/toxicidade , Albumina Sérica/análiseRESUMO
The polymorphic multigene family, var, encodes the variant antigen, Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1), present on the surface of erythrocytes infected with the human malaria parasite, P. falciparum. PfEMP1 has been implicated in the pathology of malaria through its ability to bind to host endothelial receptors and uninfected erythrocytes. Understanding the relationship between host pathology, immune response and parasite variation is crucial, but requires a method of reliably detecting and differentiating all possible var genes. Several primer pairs used to date are biased and limited in their detection capacity. Here we describe a set of PCR primers that amplify the majority of var genes in the laboratory isolates 3D7 and A4, and appear to work equally well on all isolates tested. We use these universal primers to examine the relationship between var gene transcription as assessed by reverse transcriptase-PCR (RT-PCR) with that measured by Northern analysis of parasite RNA. Phenotypically selected young parasites have multiple transcripts detected by RT-PCR, but the full-length transcript appears to be homogeneous. In addition, we demonstrate that the choice of primers used for RT-PCR is crucial in data interpretation.
Assuntos
Primers do DNA , Genes de Protozoários , Plasmodium falciparum/genética , Proteínas de Protozoários/genética , Transcrição Gênica , Sequência de Aminoácidos , Animais , Northern Blotting , Clonagem Molecular , Humanos , Malária Falciparum/parasitologia , Dados de Sequência Molecular , Família Multigênica , Plasmodium falciparum/crescimento & desenvolvimento , Reação em Cadeia da Polimerase , Proteínas de Protozoários/química , Proteínas de Protozoários/metabolismo , RNA de Protozoário/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNARESUMO
The cancer-promoting potential of fumonisin B1 (FB1) was investigated by feeding different dietary levels (10, 50, 100, 250, 500 mg FB1/kg) to diethynitrosamine (DEN)-initiated rats for 21 days. Dietary levels containing 50 mg FB1/kg and higher, markedly increased the number and size of the placental form of glutathione-S-transferase-positive (GSTP+) foci in the liver of the rats. The cancer-promoting activity of FB1 was associated with an inhibitory effect on partial hepatectomy (PH)-induced regenerative hepatocyte proliferation, as the incorporation of 3H-labelled thymidine was significantly (P < 0.05) reduced by those FB1-containing diets that exhibited cancer promotion. In vitro studies on the mitogenic activity of epidermal growth factor (EGF) in primary rat hepatocytes further supported the in vivo data in that FB1, similar to other cancer promoters such as phenobarbital and 2-acetylaminofluorene (2-AAF), alters growth stimulatory responses in primary hepatocytes. No significant (P > 0.05) changes in the sphinganine/sphingosine (Sa/So) ratio were observed in the liver of the rats fed the lowest FB1-containing diet (50 mg FB1/kg diet) that effected cancer promotion. The present study indicated that FB1 exhibited cancer-promoting activity in the absence of adverse hepatotoxic effects and at dietary levels that failed to effect cancer initiation.
Assuntos
Ácidos Carboxílicos/toxicidade , Carcinógenos Ambientais/toxicidade , Dietilnitrosamina , Fumonisinas , Neoplasias Hepáticas Experimentais/induzido quimicamente , Fígado/efeitos dos fármacos , Micotoxinas/toxicidade , Animais , Sinergismo Farmacológico , Glutationa Transferase/metabolismo , Fígado/enzimologia , Neoplasias Hepáticas Experimentais/enzimologia , Regeneração Hepática/efeitos dos fármacos , Masculino , Ratos , Ratos Endogâmicos F344RESUMO
The toxicity of low dietary levels of fumonisin B(1) (FB(1)), i.e. 1, 10 and 25 mg FB(1)/kg diet, were monitored in rats over a period of 24 months. No effects on the body weight gain and feed intake profiles were noticed, while the relative liver weight was significantly (P<0.05) reduced in the FB(1)-treated rats. Mild toxic effects, including single cell necrosis (apoptosis), proliferation of bile duct epithelial cells (DEC), and early signs of fibrosis, bile duct hyperplasia and in one case, adenofibrosis, were noticed in the liver of the rats fed the highest (25 mg/FB(1)/kg diet) dietary level. A significant (P<0.05) increase in the level of oxidative damage was also noticed in the liver of the rats of high dosage dietary group. The toxic effects were less severe in the 10 mg FB(1)/kg dietary group, whilst only a few ground glass foci were observed in the 1 mg FB(1)/kg dietary group. Hepatocyte nodules, staining positively for glutathione-S-transferase (placental form, PGST), were observed macroscopically in the 25 mg FB(1)/kg treated group and to a lesser extent in the 10 mg FB(1)/kg treated rats. The most prominent toxic lesions by FB(1) (10 and 25 mg FB(1)/kg dietary groups) in the kidneys were restricted to the tubular epithelium manifesting as granular cast, necrosis, apoptosis, calcification and the presence of regenerative foci in the proximal convoluted tubules. The existence of a cytotoxic/proliferative threshold with respect to cancer induction by FB(1) in rat liver became apparent, with a dietary level of <10-mg FB(1)/kg diet as a no effect threshold for the induction of hepatocyte nodules.
Assuntos
Ácidos Carboxílicos/toxicidade , Fumonisinas , Fígado/efeitos dos fármacos , Teratogênicos/toxicidade , Animais , Peso Corporal/efeitos dos fármacos , Ácidos Carboxílicos/administração & dosagem , Colesterol/sangue , Dieta , Relação Dose-Resposta a Droga , Rim/efeitos dos fármacos , Rim/patologia , Fígado/enzimologia , Fígado/metabolismo , Fígado/patologia , Masculino , Tamanho do Órgão/efeitos dos fármacos , Ratos , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismoRESUMO
The acute toxicity of maize culture material of eight strains of Diplodia maydis in ducklings, as well as the ability of five of these strains to induce typical diplodiosis (a neuromuscular disease) in cattle and sheep was shown. Typical diplodiosis was induced in 17 sheep and 11 cattle. Two of the five toxic strains were isolated from maize involved in diploidiosis outbreaks, the others from commercial maize. Strains inducing diplodiosis could be isolated from commercial maize from the USA, Argentina and South Africa. There was no correlation between the toxicity of D. maydis strains in ducklings and their ability to induce diplodiosis in cattle and sheep. Some isolates were acutely toxic to ducklings and rats but were unable to induce diplodiosis in either cattle or sheep. Others, equally toxic to ducklings and rats, induced diplodiosis in cattle and sheep at low dose levels. Two doses, each of 5 g/kg, of maize culture material of isolates from the USA, Argentina and South Africa induced diplodiosis in sheep. Culture material incubated for less than 8 wk could not induce diplodiosis in cattle. Acute toxicity in ducklings and rats also increased with longer incubation periods. Cultures of non-sporulating and profusely sporulating strains were equally toxic to ducklings. Heat treatment of culture material for 48 days at 45 degrees C failed to reduce toxicity in ducklings.
Assuntos
Fungos Mitospóricos/patogenicidade , Micotoxinas/toxicidade , Doenças Neuromusculares/veterinária , Ração Animal , Animais , Bovinos , Doenças dos Bovinos/microbiologia , Patos , Fungos Mitospóricos/fisiologia , Doenças Neuromusculares/microbiologia , Doenças das Aves Domésticas/microbiologia , Ratos , Ovinos , Doenças dos Ovinos/microbiologia , Especificidade da Espécie , Esporos Fúngicos/patogenicidade , Zea mays/microbiologiaRESUMO
Clinical signs of a fatal disease resembling those of canine distemper were observed in two groups of captive wild dog (Lycaon pictus) pups 13 days after vaccination with a commercially available combination vaccine for dogs which contained a live attenuated strain of canine distemper virus. Histopathological examination of tissues revealed the presence of intranuclear inclusion bodies in neurons and lesions resembling canine distemper as well as colonies of an Encephalitozoon sp. in the central nervous system and kidneys. Lesions were observed in both organs which resembled those described in other species infected with Encephalitozoon cuniculi.
Assuntos
Cinomose/parasitologia , Doenças do Cão/parasitologia , Infecções Protozoárias em Animais , Animais , Animais Selvagens/parasitologia , Apicomplexa/isolamento & purificação , Encéfalo/patologia , Encefalopatias/patologia , Encefalopatias/veterinária , Cinomose/líquido cefalorraquidiano , Cinomose/patologia , Vírus da Cinomose Canina/imunologia , Doenças do Cão/patologia , Cães , Feminino , Masculino , Infecções por Protozoários/líquido cefalorraquidiano , Infecções por Protozoários/microbiologia , Infecções por Protozoários/patologia , Vacinas Atenuadas/efeitos adversos , Vacinas Virais/efeitos adversosRESUMO
Parasites were collected from 13 Cape mountain zebras (Equus zebra zebra) in the Mountain Zebra National Park, South Africa, during four seasons of 1983 and 1984. Eighteen nematode species belonging to the families Atractidae, Habronematidae, and Strongylidae, and one species of cestode were recovered. The most abundant nematodes were Cyathostomum tetracanthum, Cylicostephanus longiconus and Probstmayria vivipara. Only one of the 10 cyathostome nematodes recovered, C. longiconus was present in every zebra.
Assuntos
Helmintíase Animal , Helmintos/classificação , Enteropatias Parasitárias/veterinária , Perissodáctilos/parasitologia , Animais , Colo/parasitologia , Feminino , Helmintíase/epidemiologia , Helmintíase/parasitologia , Helmintos/crescimento & desenvolvimento , Enteropatias Parasitárias/epidemiologia , Enteropatias Parasitárias/parasitologia , Masculino , Prevalência , África do Sul/epidemiologiaRESUMO
Bovine tuberculosis (BTB) was first detected in Kruger National Park (KNP) in a single African buffalo (Syncerus caffer) in 1990. In 1991/1992, 2,071 African buffalo were examined for BTB as part of a culling program that removed animals from all known herds in KNP. The prevalence of BTB in 1991/1992 was estimated to be 0%, 4.4% (+/-0.6%), and 27.1% (+/-1.4%), in the north, central, and south zones of KNP, respectively. In 1998, a stratified, two-stage cluster sampling method was used to estimate that the prevalence of BTB was 1.5% (+/-2.5%), 16% (+/-5.3%), and 38.2% (+/-6.3%), in the north, central, and south zones, respectively. This represented a significant increase in prevalence (P < or = 0.05) in the south and central zones, but not in the north zone. Continued monitoring of BTB in KNP is important for understanding disease transmission risks, potential population effects, and the efficacy of disease management strategies. The methodology and sample sizes used in 1998 are appropriate for future BTB monitoring in KNP.
Assuntos
Búfalos , Mycobacterium bovis , Tuberculose/epidemiologia , Doenças dos Animais/epidemiologia , Animais , Búfalos/microbiologia , Mycobacterium bovis/isolamento & purificação , Prevalência , África do Sul/epidemiologiaRESUMO
Healthy and sick crocodiles of varying sizes were examined from the Olifants River in the central part of the Kruger National Park, the Sabi River in the southern part and the Shingwedzi River in the northern region. Blood was collected for the determination of certain parameters and samples of fat, muscle, kidney and liver tissue were collected and analyzed for their heavy metal content. The results of the blood analyses are within the range recorded in the literature, but the metal analyses were inconclusive as similar data are not available for comparison. The results of the metal analyses are presented here for use as baseline and reference data.
Assuntos
Jacarés e Crocodilos/sangue , Rim/metabolismo , Fígado/metabolismo , Metais/análise , Músculos/metabolismo , Jacarés e Crocodilos/metabolismo , Animais , Feminino , Masculino , Metais/toxicidade , África do SulRESUMO
An isolate of Fusarium verticillioides (MRC826) that induced experimental leukoencephalomalacia, also caused acute toxicity when fed to pigs and administered per rumen fistula to sheep. Pigs developed severe pulmonary oedema while sheep manifested severe nephrosis and hepatosis. A less toxic isolate (F. verticillioides MRC602), fed to baboons, resulted in acute congestive heart failure or hepatic cirrhosis, depending on the dose. Both isolates were toxic to rats and caused similar lesions, namely, hepatic cirrhosis and intraventricular cardiac thrombosis.