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1.
J Am Vet Med Assoc ; 262(7): 966-972, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38503057

RESUMO

OBJECTIVE: The purpose of the study reported herein was to determine the dose of oleander extract and oleandrin (the key pharmacologically active constituent) that could be safely administered PO to dogs. ANIMALS: 42 purebred Beagle dogs were used to study an extract of Nerium oleander. METHODS: 3 studies were performed in 42 purebred young adult (ages 12 months or older) Beagle dogs using a supercritical fluid extract of N oleander leaves. The first study was an 8-day initial dose-ranging study in 2 dogs, a second 7-day repeat-dosing study was performed in 4 dogs, and the final study was performed in 32 dogs where test subjects were given extract or placebo once daily for 28 consecutive days via oral (gavage) administration followed by a 14-day recovery period. RESULTS: At 2.3 µg/kg of oleandrin, there were no observable adverse effects during the duration of the study. Adverse effects were not seen until doses exceeded 6.9 µg/kg of oleandrin, at which time mild, reversible clinical signs were noted. However, a dose > 460 µg of oleandrin/kg was fatal in 1 of 2 dogs in this study. CLINICAL RELEVANCE: The studies reported here, taken in totality, suggest that doses exceeding 6.9 µg/kg of oleandrin may be associated with cardiac abnormalities. An estimated no treatment effective adverse event oral dose of oleandrin appears to be 4.6 µg of oleandrin/kg. Higher doses may be tolerable but should be used with appropriate monitoring.


Assuntos
Cardenolídeos , Relação Dose-Resposta a Droga , Nerium , Extratos Vegetais , Animais , Cães , Cardenolídeos/administração & dosagem , Masculino , Administração Oral , Feminino , Extratos Vegetais/administração & dosagem
2.
Am J Vet Res ; : 1-7, 2024 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-39362280

RESUMO

OBJECTIVE: To perform testing for cytokines involved in dermal inflammatory reactions and to document and compare the effects of an oleander extract (OE), oleandrin, and oclacitinib on biomarkers relevant to allergic reactions. The effects of these compounds under inflamed culture conditions are of direct importance to the treatment of canine atopic dermatitis. METHODS: Testing involved primary canine dermal fibroblasts and the canine DH82 macrophage cell line; both cell types are important for initiating, regulating, and resolving dermal allergic reactions via cytokine communication. RESULTS: Under inflamed conditions, OE and oleandrin downregulated key cytokines secreted by canine dermal fibroblasts and the DH82 macrophage cell line; all of which are treatment targets in dermatitis. In the DH82 macrophage cultures, the most noteworthy reductions involved IL-6, IL-12/IL-23p40, interferon-γ, tumor necrosis factor-α, VEGF, and nerve growth factor-ß. Oclacitinib triggered reductions of some cytokines involved in allergic reactions, including TGF-ß1, IL-12/IL-23p40, and tumor necrosis factor-α; however, these reductions were less robust than the reductions triggered by OE and oleandrin and accompanied by increases in other cytokines involved in dermal inflammation, including IL-6, interferon-γ, and nerve growth factor-ß. In cultures of primary dermal fibroblasts, OE and oleandrin reduced the levels of IL-8 and monocyte chemoattractant protein-1, whereas oclacitinib had little or no effect. CONCLUSIONS: Oleander extract and oleandrin directly modulate immune responses under inflamed conditions. Moreover, OE and oleandrin appear to provide a more beneficial overall cytokine regulation than oclacitinib under inflamed culture conditions. CLINICAL RELEVANCE: These results suggest that OE and oleandrin are efficacious agents to treat canine atopic dermatitis. Future studies should evaluate the efficacy of these compounds in dogs affected by atopic dermatitis.

3.
J Magn Reson Imaging ; 36(5): 1203-12, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22826184

RESUMO

PURPOSE: To evaluate the differences in image quality of two macrocyclic gadolinium-based contrast agents, gadobutrol and gadoterate meglumine, using time-resolved, contrast-enhanced MR angiography (CE-MRA) in a porcine carotid artery aneurysm model and to compare image quality between dynamic and conventional, single acquisition CE-MRA. MATERIALS AND METHODS: Bilateral carotid aneurysms were created surgically in this Institutional Animal Care and Use Committee approved study. Dynamic CE-MRA studies optimized for high temporal resolution were performed at 3 Tesla. Scans using equivalently dosed (on a per mmol basis) gadobutrol and gadoterate meglumine were compared qualitatively and quantitatively in terms of contrast-to-noise ratio (CNR). Higher spatial resolution dynamic and conventional CE-MRA were also compared. RESULTS: N = 16 aneurysms were assessed. Qualitative evaluation of dynamic CE-MRA scans demonstrated a preference for gadobutrol over gadoterate meglumine. Significantly higher aneurysm CNR was found with gadobutrol (133 ± 44) versus gadoterate meglumine, the latter at both equivalent and double injection rates (94 ± 35 and 102 ± 38). In a blinded assessment, conventional CE-MRA was preferred qualitatively when compared with dynamic CE-MRA. However, dynamic CE-MRA was generally capable of providing diagnostic image quality. CONCLUSION: Gadobutrol is preferred to gadoterate meglumine for high temporal resolution dynamic CE-MRA, a fact with important clinical implications for low dose CE-MRA protocols in patients at risk for nephrogenic systemic fibrosis. Conventional high resolution CE-MRA provides superior image quality when compared with dynamic CE-MRA.


Assuntos
Aneurisma/patologia , Doenças das Artérias Carótidas/patologia , Quelantes/uso terapêutico , Modelos Animais de Doenças , Angiografia por Ressonância Magnética/métodos , Meglumina , Compostos Organometálicos , Animais , Meios de Contraste , Humanos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Suínos
4.
Vet Surg ; 41(8): 915-7, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23198919

RESUMO

OBJECTIVE: To describe a minimally invasive surgical technique for procedures involving the caudoventral compartment of the thoracic cavity. STUDY DESIGN: Case series. ANIMALS: Dogs (n = 13). METHODS: Thirteen dogs; undergoing epicardial pacemaker implantation (9), palliative pericardial window (2), perforated right ventricle repair with epicardial pacemaker implantation (1), and peritoneopericardial diaphragmatic hernia (1) were operated by a transxiphoid approach. Dogs were positioned in dorsal recumbency and the bony xiphoid process was dissected free of adjoining tissue and transected proximally and distally. The distal transection was proximal to the cartilaginous junction of the process and the diaphragm. Entry to the thoracic cavity without penetration of the abdomen provided access for surgical treatment. RESULTS: All dogs recovered without complication. No dogs required thoracostomy tube placement. CONCLUSIONS: Transxiphoid approach is minimally invasive and provides adequate exposure for disorders of the caudoventral thoracic cavity.


Assuntos
Procedimentos Cirúrgicos Cardíacos/veterinária , Doenças do Cão/cirurgia , Marca-Passo Artificial/veterinária , Animais , Procedimentos Cirúrgicos Cardíacos/métodos , Cães , Feminino , Cardiopatias/cirurgia , Cardiopatias/veterinária , Ventrículos do Coração/patologia , Ventrículos do Coração/cirurgia , Hérnia Diafragmática/veterinária , Masculino , Técnicas de Janela Pericárdica/veterinária
5.
J Am Anim Hosp Assoc ; 46(4): 235-40, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20610695

RESUMO

Dogs with congenital portosystemic shunt (PSS) are typically diagnosed before 2 years of age. The objective of this study was to determine if miniature schnauzers are more likely to be diagnosed with congenital PSS at an older age than are other breeds. This retrospective study examined the case records of 171 dogs diagnosed with congenital PSS; dogs were included if they were definitively diagnosed as having congenital PSS by nuclear scintigraphy, contrast portography, and/or exploratory surgery. Seven (23%) of 31 miniature schnauzers diagnosed with congenital PSS were 7 years of age or older at the time of diagnosis, compared to 3.4% for all other breeds. Miniature schnauzers had a relative prevalence ratio of 6.3 (95% confidence interval 2.2 to 18.6; P=0.001) for being diagnosed at or after 7 years of age when compared to all other breeds of dogs. Clinical signs of congenital PSS may not manifest sufficiently to cause an owner to seek veterinary care for some dogs until they are older. Congenital PSS should be considered in mature dogs, particularly miniature schnauzers, that are presented with signs potentially consistent with hepatic encephalopathy.


Assuntos
Doenças do Cão/congênito , Sistema Porta/anormalidades , Fatores Etários , Animais , Doenças do Cão/diagnóstico , Cães , Feminino , Predisposição Genética para Doença , Masculino , Linhagem , Estudos Retrospectivos
6.
J Zoo Wildl Med ; 41(1): 90-4, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20722259

RESUMO

Hiatal hernia was diagnosed in three exotic felines-lynx (Lynx lynx), cougar (Puma concolore), and lion (Panthera leo). All cats had a history of anorexia. Thoracic and abdominal radiographs showed evidence of a soft tissue mass within the caudal mediastinum suggestive of a hiatal hernia in all animals. A barium esophagram was performed in one case. All animals underwent thoracic or abdominal surgery for hernia reduction. Surgical procedures included: intercostal thoracotomy with herniorrhaphy and esophagopexy (lynx and cougar), and incisional gastropexy (lion). Concurrent surgical procedures performed were gastrotomy for gastric foreign body removal and jejunostomy tube placement. Clinical signs related to the hiatal hernia disappeared after surgery and recurrence of signs was not reported for the time of follow-up.


Assuntos
Hérnia Hiatal/veterinária , Leões , Lynx , Puma , Animais , Hérnia Hiatal/diagnóstico por imagem , Hérnia Hiatal/patologia , Hérnia Hiatal/cirurgia , Masculino , Radiografia
7.
Am J Physiol Heart Circ Physiol ; 297(6): H2044-53, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19717726

RESUMO

A porcine aortic coarctation model was used to examine regulation of gene expression in early hypertensive vascular remodeling. Aortic segments were collected proximal (high pressure) and distal (low pressure) to the coarctation after 2 wk of sustained hypertension (mean arterial pressure>150 mmHg). Porcine 10K oligoarrays used for gene expression profiling of the two regions of aorta revealed downregulation of cytoskeletal and upregulation of extracellular region genes relative to the whole genome. A genomic database search for transforming growth factor-beta (TGF-beta) control elements showed that 19% of the genes that changed expression due to hypertension contained putative TGF-beta control elements. Real-time RT-PCR and microarray analysis showed no change in expression of TGF-beta1, TGF-beta2, TGF-beta3, or bone morphogenetic proteins-2 and -4, yet immunohistochemical staining for phosphorylated SMAD2, an indicator of TGF-beta signaling, and for phosphorylated SMAD1/5/8, an indicator of signaling through the bone morphogenetic proteins, showed the highest percentage of positively stained cells in the proximal aortic segments of occluded animals. For TGF-beta signaling, this increase was significantly different than for sham-operated controls. Western blot analysis showed no difference in total TGF-beta1 protein levels with respect to treatment or aortic segment. Immunohistochemistry showed that the protein levels of latency-associated peptide was decreased in proximal segments of occluded animals. Collectively, these results suggest that activation of TGF-beta, but not altered expression, may be a major mechanism regulating early hypertensive vascular remodeling.


Assuntos
Aorta/metabolismo , Coartação Aórtica/genética , Hipertensão/genética , Transdução de Sinais/genética , Fator de Crescimento Transformador beta/genética , Animais , Aorta/diagnóstico por imagem , Aorta/fisiopatologia , Coartação Aórtica/diagnóstico por imagem , Coartação Aórtica/metabolismo , Coartação Aórtica/fisiopatologia , Western Blotting , Proteínas Morfogenéticas Ósseas/genética , Proteínas Morfogenéticas Ósseas/metabolismo , Diferenciação Celular/genética , Bases de Dados Genéticas , Modelos Animais de Doenças , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica , Hipertensão/diagnóstico por imagem , Hipertensão/metabolismo , Hipertensão/fisiopatologia , Imuno-Histoquímica , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/patologia , Análise de Sequência com Séries de Oligonucleotídeos , Fosforilação , Reação em Cadeia da Polimerase , Fluxo Sanguíneo Regional/genética , Proteínas Smad/genética , Proteínas Smad/metabolismo , Suínos , Porco Miniatura , Fator de Crescimento Transformador beta/metabolismo , Ultrassonografia Doppler em Cores
8.
Vet Surg ; 38(4): 439-44, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19538663

RESUMO

OBJECTIVES: To evaluate the clinical outcome of left partial arytenoidectomy by video-assisted laser diode photoablation as a surgical treatment for canine laryngeal paralysis (LP). STUDY DESIGN: Case series. ANIMALS: Dogs with bilateral LP (n=20). METHODS: After endoscopic diagnosis of bilateral LP, left partial arytenoidectomy was performed by photoablation of arytenoid cartilage tissue using a diode laser (600 microm diameter, 15 W power, 980 nm wave length) to increase the width of the rima glottidis. Outcome was evaluated endoscopically (1 and 6 months) and clinically (1, 6, and 12 months). RESULTS: No substantial complications occurred during photoablation or in the immediate postoperative period. Postoperative width of the rima glottidis ranged from 6 to 10 mm at its widest aspect. At 1 month, respiratory function after walking and short running appeared good. Clinical and endoscopic examination revealed good outcome at 1 and 6 months. At 6 months, there was no evidence of hypertrophic scar, hypertrophic granulation tissue, or stricture of the laryngeal glottis in any dog. Two dogs developed aspiration pneumonia after 12 months. CONCLUSIONS: Partial arytenoidectomy using video-assisted diode laser photoablation appears to be an effective technique for treating LP. CLINICAL RELEVANCE: Partial arytenoidectomy by diode laser photoablation should be considered as an alternative technique for treatment of canine LP.


Assuntos
Cartilagem Aritenoide/cirurgia , Doenças do Cão/cirurgia , Terapia a Laser/veterinária , Paralisia das Pregas Vocais/veterinária , Animais , Cães , Terapia a Laser/efeitos adversos , Terapia a Laser/métodos , Lasers Semicondutores , Complicações Pós-Operatórias/veterinária , Paralisia das Pregas Vocais/cirurgia
9.
J Histochem Cytochem ; 56(4): 359-70, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18071063

RESUMO

Arteries undergo marked structural and functional changes in human and experimental hypertension that generally involve smooth muscle cell (SMC) hypertrophy/hyperplasia as well as abnormal extracellular matrix turnover. In this study we examined time courses of changes in SMC activity and matrix protein content in a novel mini-pig aortic coarctation model. Cell proliferation was evaluated by immunostaining of Ki-67, apoptosis was assessed by TUNEL, and phenotypic changes were monitored by immunostaining three SMC contractile markers (caldesmon, calponin, and smoothelin). Changes in medial collagen and elastin were examined by picrosirius red and Verhoeff-van Gieson staining, respectively. LabVIEW-based image analysis routines were developed to objectively and efficiently quantify the (immuno)histochemical results. We found that significant cell proliferation and matrix production occurred in the early stages of this coarctation model and then declined gradually; the SMCs also tended to exhibit a less contractile phenotype following these cellular and extracellular changes. Specifically, different aspects of the phenotypic changes associated with hypertension occurred at different rates: cell proliferation and collagen production occurred early and peaked by 2 weeks, whereas changes in contractile protein expression continued to decrease over the entire 8-week study period. Temporal changes found in this study emphasize the importance of simultaneously tracing time courses of SMC growth and differentiation as well as matrix protein production and content. SMCs are multifunctional, and caution must be used to not overdefine phenotype. This manuscript contains online supplemental material at http://www.jhc.org. Please visit this article online to view these materials.


Assuntos
Aorta/patologia , Hipertensão/patologia , Miócitos de Músculo Liso/patologia , Actinas/metabolismo , Animais , Aorta/metabolismo , Apoptose , Proteínas de Ligação ao Cálcio/metabolismo , Proteínas de Ligação a Calmodulina/metabolismo , Proliferação de Células , Colágeno/metabolismo , Interpretação Estatística de Dados , Proteínas da Matriz Extracelular/metabolismo , Hipertensão/metabolismo , Processamento de Imagem Assistida por Computador , Imuno-Histoquímica , Marcação In Situ das Extremidades Cortadas , Antígeno Ki-67/metabolismo , Proteínas dos Microfilamentos/metabolismo , Proteínas Musculares/metabolismo , Miócitos de Músculo Liso/metabolismo , Software , Suínos , Porco Miniatura , Fatores de Tempo , Calponinas
10.
J Cardiovasc Pharmacol Ther ; 13(3): 214-25, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18757834

RESUMO

Endothelial dysfunction (ED) is characterized by impaired nitric oxide (NO) signaling, decreased NO-dependent vasodilatation, increased vascular inflammation, and diminished response to angiogenic factors. TP508 (Chrysalin), an angiogenic tissue repair peptide, was tested for potential effects on myocardial revascularization and ED using a porcine model of chronic myocardial ischemia. TP508 increased perfusion in ischemic regions up to16-fold (P < .02) and doubled myocardial wall thickening (P < .02) relative to placebo controls. Ischemic arterioles exhibited impaired NO-mediated vasodilation and diminished NO production. TP508 reversed ischemic effects, increasing NO-mediated vasodilation (P < .05), endothelial nitric oxide synthase (eNOS) expression, and NO production. In human endothelial cells, TP508 stimulated eNOS activation (1.84 +/- 0.2-fold; P < .02), increased NO production (85 +/- 18%; P < .02), and prevented hypoxia-induced eNOS downregulation (P < .01). Thus, TP508 reverses ED both in porcine ischemic hearts and cultured human endothelial cells. These results suggest potential therapeutic benefit of TP508 in myocardial revascularization and treatment of ED-related diseases.


Assuntos
Indutores da Angiogênese/farmacologia , Circulação Coronária/efeitos dos fármacos , Vasos Coronários/efeitos dos fármacos , Endotélio Vascular/efeitos dos fármacos , Isquemia Miocárdica/tratamento farmacológico , Revascularização Miocárdica/métodos , Fragmentos de Peptídeos/farmacologia , Animais , Hipóxia Celular , Células Cultivadas , Doença Crônica , Angiografia Coronária , Vasos Coronários/metabolismo , Vasos Coronários/fisiopatologia , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Ecocardiografia sob Estresse , Endotélio Vascular/metabolismo , Endotélio Vascular/fisiopatologia , Humanos , Isquemia Miocárdica/metabolismo , Isquemia Miocárdica/patologia , Isquemia Miocárdica/fisiopatologia , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase Tipo III/metabolismo , Suínos , Porco Miniatura , Trombina , Vasodilatação/efeitos dos fármacos , Vasodilatadores/farmacologia
11.
Med Educ ; 42(6): 607-12, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18435713

RESUMO

CONTEXT: Although surgeons and athletes frequently use mental imagery in preparing to perform, mental imagery has not been extensively researched as a learning technique in medical education. OBJECTIVE: A mental imagery rehearsal technique was experimentally compared with textbook study to determine the effects of each on the learning of basic surgical skills. METHODS: Sixty-four Year 2 medical students were randomly assigned to 2 treatment groups in which they undertook either mental imagery or textbook study. Both groups received the usual skills course of didactic lectures, demonstrations, physical practice with pigs' feet and a live animal laboratory. One group received additional training in mental imagery and the other group was given textbook study. Performance was assessed at 3 different time-points using a reliable rating scale. RESULTS: Analysis of variance on student performance in live rabbit surgery revealed a significant interaction favouring the imagery group over the textbook study group. CONCLUSIONS: The mental imagery technique appeared to transfer learning from practice to actual surgery better than textbook study.


Assuntos
Educação de Graduação em Medicina/métodos , Imagem Eidética , Cirurgia Geral/educação , Ensino/métodos , Atitude do Pessoal de Saúde , Humanos , Imaginação , Processos Mentais , Autoavaliação (Psicologia) , Estudantes de Medicina/psicologia , Inquéritos e Questionários
12.
J Extra Corpor Technol ; 40(2): 116-22, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18705547

RESUMO

Heparin-induced thrombocytopenia can be a life-threatening sequel to conventional use of unfractionated heparin in cardiopulmonary bypass (CPB). This study evaluated the pharmacokinetic/pharmacodynamic (PK/PD) and efficacy profile of a novel direct thrombin inhibitor, TGN 255, during cardiac surgery in dogs. Point-of-care coagulation monitoring was also compared against the plasma concentrations of TRI 50c, the active metabolite of TGN 255. The study was conducted in three phases using 10 animals: phase 1 was a dose-ranging study in conscious animals (n = 6), phase 2 was a similar but terminal dose-ranging study in dogs undergoing CPB (n = 6), and phase 3 was with animals undergoing simulated mitral valve repair (terminal) using optimal TGN 255 dose regimens derived from phases I and II (n = 4). During the study, PD markers and drug plasma levels were determined. In addition, determinations of hematologic markers and blood loss were undertaken. Phase 1 studies showed that a high-dose regimen of a 5-mg/kg bolus and infusion of 20 mg/kg/h elevated PD markers in conscious animals, at which time there were no measured effects on platelet or red blood cell counts, and the mean plasma concentration of TRI 50C was 20.6 microg/mL. In the phase 2 CPB dose-ranging study, this dosing regimen significantly elevated all the PD markers and produced hemorrhagic and paradoxical thrombogenic effects. In the phase 3 surgical study, a lower TGN 255 dose regimen of a 2.5-mg/kg bolus plus 10 mg/kg/h produced anticoagulation, elevated PD markers, and produced minimal post-operative blood loss in the animals. Plasma levels of TRI 50C trended well with the conventional point-of-care coagulation monitoring. TGN 255 provided effective anticoagulation in a canine CPB procedure, enabling successful completion with minimal blood loss. These findings support further evaluation of TGN 255 as an anticoagulant for CPB.


Assuntos
Anticoagulantes/farmacocinética , Ácidos Borônicos/farmacocinética , Ponte Cardiopulmonar , Dipeptídeos/farmacocinética , Valva Mitral/cirurgia , Animais , Anticoagulantes/administração & dosagem , Modelos Animais de Doenças , Cães , Relação Dose-Resposta a Droga
13.
Arterioscler Thromb Vasc Biol ; 26(9): 2035-42, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16794224

RESUMO

OBJECTIVE: Overproduction of reactive oxygen species such as hydrogen peroxide (H2O2) has been implicated in various cardiovascular diseases. However, mechanism(s) underlying coronary vascular dysfunction induced by H2O2 is unclear. We studied the effect of H2O2 on dilation of coronary arterioles to endothelium-dependent and endothelium-independent agonists. METHODS AND RESULTS: Porcine coronary arterioles were isolated and pressurized without flow for in vitro study. All vessels developed basal tone and dilated dose-dependently to activators of nitric oxide (NO) synthase (adenosine and ionomycin), cyclooxygenase (arachidonic acid), and cytochrome P450 monooxygenase (bradykinin). Intraluminal incubation of vessels with H2O2 (100 micromol/L, 60 minutes) did not alter basal tone but inhibited vasodilations to adenosine and ionomycin in a manner similar as that by NO synthase inhibitor L-NAME. H2O2 affected neither endothelium-dependent responses to arachidonic acid and bradykinin nor endothelium-independent dilation to sodium nitroprusside. The inhibited adenosine response was not reversed by removal of H2O2 but was restored by excess L-arginine. Inhibition of L-arginine consuming enzyme arginase by alpha-difluoromethylornithine or N(omega)-hydroxy-nor-L-arginine also restored vasodilation. Administering deferoxamine, an inhibitor of hydroxyl radical production, prevented the H2O2-induced impairment of vasodilation to adenosine. Western blot and reverse-transcription polymerase chain reaction results indicated that arginase I was upregulated after treating vessels with H2O2. CONCLUSIONS: H2O2 specifically impairs endothelium-dependent NO-mediated dilation of coronary microvessels by reducing L-arginine availability through upregulation of arginase. The formation of hydroxyl radicals from H2O2 may contribute to this process.


Assuntos
Arginase/metabolismo , Vasos Coronários/fisiopatologia , Endotélio Vascular/metabolismo , Peróxido de Hidrogênio/farmacologia , Óxido Nítrico/metabolismo , Oxidantes/farmacologia , Vasodilatação/efeitos dos fármacos , Animais , Arginina/metabolismo , Arteríolas/fisiopatologia , Endotélio Vascular/efeitos dos fármacos , Sequestradores de Radicais Livres/farmacologia , Óxido Nítrico Sintase Tipo III/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Suínos , Regulação para Cima
14.
J Am Osteopath Assoc ; 117(6): 370-376, 2017 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-28556859

RESUMO

The One Health concept focuses on the interrelationship between the health of humans, animals, and the environment. There is a delicate balance among these relationships, and when an imbalance exists, the effects can be catastrophic. Such an imbalance occurred in 2010, when elevated lead exposure in rural communities in northwestern Nigeria resulted in the deaths of an estimated 400 children younger than 5 years in a 12-month period. Before the children became ill, waterfowl began to die in great numbers, a connection that would not be realized until much later. This review covers toxicodynamics and the neurotoxic effects of lead in the developing central nervous system, the role that animals can play in recognizing lead exposure and contamination, and environmental sources of lead exposure. The experiences in Nigeria may be especially pertinent to the emerging problems associated with lead exposure and poisoning in the United States.


Assuntos
Anseriformes , Biomarcadores Ambientais , Saúde Ambiental , Intoxicação por Chumbo/epidemiologia , Saúde Única , Saúde da População Rural , Animais , Pré-Escolar , Humanos , Intoxicação por Chumbo/prevenção & controle , Nigéria/epidemiologia
15.
Appl Radiat Isot ; 97: 193-200, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25638490

RESUMO

A new treatment strategy based on direct injections of (90)Y-hydroxide into the tumor bed in dogs with osteosarcoma was studied. Direct injections of the radiopharmaceutical into the tumor bed were made according to a pretreatment plan established using (18)F-FDG images. Using a special drill, cannulas were inserted going through tissue, tumor and bone. Using these cannulas, direct injections of the radiopharmaceutical were made. The in vivo biodistribution of (90)Y-hydroxide and the anatomical tumor bed were imaged using a time-of-flight (TOF) PET/CT scanner. The material properties of the tissues were estimated from corresponding CT numbers using an electron-density calibration. Radiation absorbed dose estimates were calculated using Monte Carlo methods where the biodistribution of the pharmaceutical from PET images was sampled using a collapsing 3-D rejection technique. Dose distributions in the tumor bed and surrounding tissues were calculated, showing significant heterogeneity with multiple hot spots at injection sites. Dose volume histograms showed that approximately 33.9% of bone and tumor and 70.2% of bone marrow and trabecular bone received an absorbed dose over 200Gy; approximately 3.2% of bone and tumor and 31.0% of bone marrow and trabecular bone received a total dose of over 1000Gy.

16.
J Biomed Opt ; 9(5): 934-9, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15447014

RESUMO

Fluorescence spectroscopic detection using 5-amino levulinic acid (ALA) may provide an effective, noninvasive approach for early detection of oral cancer. In the present study, the use of ALA-induced fluorescence ratio (red/orange) to differentiate between normal and gingivitis-affected gingiva is investigated. Five dogs with varying degrees of gingivitis are studied. Based on previous studies, a dose of 25 mg/kg of ALA is administered intravenously to the dogs. Autofluorescence and ALA-induced fluorescence from three sites: normal gingiva, pigmented gingiva, and gingivitis, are detected with a fiber optic probe coupled to an optical multichannel analyzer. Four dogs show higher and earlier ALA-induced fluorescence from the gingivitis site as compared to the unpigmented gingiva. In two dogs, ALA-induced fluorescence peaks are seen 15 min after ALA administration. Statistical analysis using mean separation procedures reveal differences in the fluorescence from the various sites in each dog. Using a fluorescence (ratio) cutoff of 1.5, the sensitivity and specificity are found to be 92 and 80%, respectively, 1 h after administration of ALA. The indications from this study-that the characteristic protoporphyrin IX (PpIX) fluorescence is seen earlier and in higher magnitude in more vascular areas of the oral cavity-has implications for oral cancer diagnosis.


Assuntos
Algoritmos , Ácido Aminolevulínico , Diagnóstico por Computador/métodos , Gengivite/classificação , Gengivite/diagnóstico , Espectrometria de Fluorescência/métodos , Animais , Modelos Animais de Doenças , Cães , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
17.
J Invest Surg ; 16(1): 35-44, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-12554338

RESUMO

We have developed a reproducible renovascular model of hypertension via a controllable, suprarenal aortic coarctation in the pig. This model has many potential applications, including investigation of the effects of acute hypertension in the conscious animal; identification of cardiac and vascular adaptations to chronic hypertension and their reversal; determining the effect of pharmacologic agents or other interventions on hypertension; and furthering our understanding of the implications of chronic hypertension on neurologic function. A totally implantable system was devised by attaching a reinforced silicone vascular occluder to a vascular access port. The occluder was placed around the suprarenal aorta proximal to the diaphragm. Ten pigs were made hypertensive by sequentially inflating the occluder. In six pigs, telemetric monitoring of blood pressure was used to determine when the pigs had reached target pressures (mean arterial blood pressure >150 mm Hg). Four pigs did not have telemetry units placed and blood pressure and heart rate were monitored for 4 weeks by periodically restraining the pigs in a sling. Two pigs reversed their occlusion due to presumed technical errors; the remaining pigs were studied for 4 (n = 5) or 8 (n = 3) weeks and then euthanized. Advantages of this model of aortic coarctation are that the occlusions are performed in awake animals and excessive occlusion of the aorta resulting in neurologic dysfunction or other distress to the animal can be easily corrected by simply withdrawing a small amount of the fluid used for inflation of the occluder. Additionally, removal of the constriction does not require a second surgical procedure.


Assuntos
Modelos Animais de Doenças , Hipertensão/fisiopatologia , Porco Miniatura , Aldosterona/sangue , Animais , Coartação Aórtica/fisiopatologia , Pressão Sanguínea , Masculino , Renina/sangue , Telemetria
18.
J Vet Intern Med ; 18(3): 307-10, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15188816

RESUMO

Chylothorax is a devastating disease, and the success rates from either medical or surgical management are less than satisfactory. In some animals with chylothorax, a thickening of the pericardium occurs that is associated with chronic irritation induced by chyle. We hypothesized that pericardial thickening would lead to increased right-sided venous pressures and that abnormal venous pressures would act to impede the drainage of chyle via lymphaticovenous communications after thoracic duct (TD) ligation. We also hypothesized that serosanguineous effusions that occurred after TD ligation could effectively be treated or prevented by pericardectomy in affected animals. TD ligation plus pericardectomy was performed in 17 animals, and pericardectomy alone was performed in an additional 3 animals that presented during a 5.5-year period to the Texas A&M University (College Station, TX). Nineteen animals presented for an evaluation of idiopathic chylothorax (9 dogs and 10 cats), and 1 dog presented for serosanguineous pleural fluid after TD ligation that had been performed elsewhere. Echocardiography was normal in all animals, except for a subjectively thickened pericardium in 7 cats and 6 dogs. Clinical signs of pleural fluid accumulation resolved in 10 of 10 dogs and in 8 of 10 cats after surgery. The overall success rate for the surgical treatment of chylothorax (ie, the resolution of pleural fluid accumulation) in this study was 90% (100% in dogs and 80% in cats). These data suggest that TD ligation in conjunction with pericardectomy has a favorable outcome in animals with idiopathic chylothorax.


Assuntos
Doenças do Gato/cirurgia , Quilotórax/veterinária , Doenças do Cão/cirurgia , Ducto Torácico/cirurgia , Animais , Gatos , Quilotórax/cirurgia , Cães , Feminino , Ligadura/veterinária , Masculino , Pericardiectomia/veterinária , Resultado do Tratamento
19.
Am J Vet Res ; 64(11): 1347-53, 2003 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-14620768

RESUMO

OBJECTIVES: To devise a technique for gradual occlusion of the caudal vena cava in dogs and determine effects of complete occlusion of the caudal vena cava. ANIMALS: 8 mixed-breed hounds that weighed between 25 and 30 kg. PROCEDURE: Baseline evaluation of dogs included serum biochemical analyses and determination of glomerular filtration rate (GFR) with dynamic renal scintigraphy and plasma clearance analysis. An occluder was placed around the vena cava in the region cranial to the renal veins. The occluder was attached to a vascular access port. The vena cava was gradually occluded over 2 weeks. The GFR was measured every 2 weeks after surgery, and venograms were performed every 3 weeks after surgery. Blood samples were collected every 48 hours for the first week and then weekly thereafter to measure BUN and creatinine concentrations and activities of alanine transaminase, alkaline phosphatase, and creatinine kinase. Dogs were euthanatized 6 weeks after surgery, and tissues were submitted for histologic examination. The GFR and biochemical data were compared with baseline values. RESULTS: Gradual occlusion of the caudal vena cava was easily and consistently performed with this method, and adverse clinical signs were not detected. Formation of collateral vessels allowed overall GFR to remain constant despite a decrease in function of the left kidney. Measured biochemical values did not deviate from reference ranges. CONCLUSIONS AND CLINICAL RELEVANCE: Gradual occlusion of the caudal vena cava may allow removal of adrenal gland tumors with vascular invasion that would otherwise be difficult or impossible to resect.


Assuntos
Cães/fisiologia , Veia Cava Inferior/fisiologia , Veia Cava Inferior/cirurgia , Alanina Transaminase/sangue , Fosfatase Alcalina/sangue , Animais , Nitrogênio da Ureia Sanguínea , Creatina Quinase/sangue , Feminino , Taxa de Filtração Glomerular , Masculino , Valores de Referência
20.
J Am Vet Med Assoc ; 221(11): 1586-90, 1574, 2002 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-12479329

RESUMO

Transvenous retrograde portography for identification and characterization of portosystemic shunts in dogs A method for transvenous retrograde portography (TRP) in dogs suspected to have a portosystemic shunt (PSS) and results in 20 dogs are described. For TRP, dogs were anesthetized and positioned in left lateral recumbency A dual-lumen balloon-tipped catheter was inserted into the right jugular vein and advanced into the azygos vein. The balloon was inflated to occlude the azygos vein, and contrast material was injected during fluoroscopic evaluation. The catheter was then positioned in the caudal vena cava just cranial to the diaphragm. The balloon was again inflated to occlude the vena cava, and contrast material was again injected. Once a shunt was identified, selective catheterization was attempted with a guide wire and angled catheter. A PSS was identified in 18 of the 20 dogs. In 10 of the 18, the shunt vessel could be selectively catheterized, allowing measurement of portal pressures while the shunt was occluded with the balloon. In 1 dog, results of TRP were normal, but subsequent exploratory celiotomy revealed a single extrahepatic PSS, which was surgically attenuated. The other dog in which results of TRP were normal did not have a macroscopic PSS. In dogs suspected to have a PSS, TRP may be a useful adjunctive diagnostic test that is less invasive than operative mesenteric vein portography and allows measurement of portal pressures before and after temporary shunt occlusion.


Assuntos
Doenças do Cão/diagnóstico por imagem , Sistema Porta/anormalidades , Portografia/veterinária , Animais , Cateterismo/veterinária , Doenças do Cão/cirurgia , Cães , Ligadura/veterinária , Pressão na Veia Porta , Sistema Porta/diagnóstico por imagem , Portografia/métodos , Resultado do Tratamento , Veia Cava Inferior/cirurgia
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