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2.
Equine Vet J ; 47(6): 741-4, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26278206

RESUMEN

REASONS FOR PERFORMING STUDY: The cardiovascular effects and duration of action of hypertonic saline are not yet fully understood in the horse. OBJECTIVE: To determine the effects of hypertonic saline on cardiac measurements derived from echocardiography over a period of 90 min after infusion in euvolaemic and healthy horses. STUDY DESIGN: Experimental study. METHODS: Five healthy conscious euvolaemic horses were infused with 5 ml/kg bwt hypertonic saline via a jugular catheter over 1 h. Immediately prior to infusion and at 0, 20, 40, 60 and 90 min after the completion of the infusion, echocardiographic images were obtained from the right parasternal window. The left ventricular internal diameter at end diastole and left ventricular internal diameter in peak systole were measured and ventricular volume measurements were calculated by the Teicholz method. Data were analysed using a mixed effects model, which included horse as a random effect. The effect of observation time was assessed accounting for correlation between observations. RESULTS: Fractional shortening and ejection fraction increased significantly 40 min after completion of infusion. Left ventricular internal diameter at end diastole, end diastolic volume and stroke volume all followed the same pattern and were increased at 20, 40 and 60 min compared to preinfusion values. There were also significant differences between the 0 and 40, 40 and 90, 60 and 90 time points. Other parameters did not differ significantly between time points. CONCLUSIONS: Hypertonic saline increases end-diastolic and stroke volume for approximately 1 h after completion of a 60 min infusion in euvolaemic horses. This adds to the evidence available to clinicians regarding the duration of action of hypertonic saline.


Asunto(s)
Ecocardiografía/veterinaria , Corazón/fisiología , Hemodinámica/efectos de los fármacos , Caballos/fisiología , Solución Salina Hipertónica/farmacología , Animales , Factores de Tiempo
3.
Equine Vet J ; 45(3): 367-71, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-23094967

RESUMEN

Pneumocephalus is occasionally encountered in horses but poorly described in the literature. The study aimed to describe historical, clinical and diagnostic imaging findings and outcome in horses to increase the awareness and recognition of the condition amongst equine practitioners, allowing appropriate management of these cases. Cases of pneumocephalus from 4 participating institutions were identified and case details extracted from the medical records. Five cases of pneumocephalus were identified. Head trauma with suspected or confirmed fractures of the sinuses was the underlying cause in 4 cases, while the remaining horse was thought to have developed pneumocephalus secondary to sinusitis or trauma. Diagnosis was established radiographically in 4 cases and by computed tomography in a fifth. Gas was noted between the cranial vault and the brain, in the lateral ventricles, in the brain parenchyma and within the cranial cervical canal. The gas accumulation resolved gradually in all horses and did not appear independently to result in neurological compromise. Long-term outcome was available for 3 cases, 2 of which were ultimately subjected to euthanasia due to neurological deficits. Pneumocephalus is a possible consequence of head trauma or sinusitis in horses; although the finding is frequently incidental, it has the potential to develop into a life-threatening complication. Imaging the complete skull and cranial cervical spine is important to allow identification and appropriate management of these cases. The use of computed tomography enables easier identification and localisation of the gas accumulation within the central nervous system.


Asunto(s)
Enfermedades de los Caballos/patología , Neumocéfalo/veterinaria , Animales , Femenino , Enfermedades de los Caballos/diagnóstico por imagen , Enfermedades de los Caballos/etiología , Caballos , Masculino , Neumocéfalo/diagnóstico por imagen , Neumocéfalo/patología , Neumocéfalo/cirugía , Radiografía , Fracturas Craneales/complicaciones , Fracturas Craneales/patología , Fracturas Craneales/cirugía , Fracturas Craneales/veterinaria
4.
Equine Vet J Suppl ; (41): 87-90, 2012 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-22594033

RESUMEN

REASONS FOR PERFORMING STUDY: Many Thoroughbred foals are intended to be sold at public auction. The impact of disease conditions necessitating hospital treatment as a foal on future sales performance is unknown. OBJECTIVES: To determine whether Thoroughbred horses that were treated in a hospital before age 125 days and presented to public auction sell for a different mean price than controls. METHODS: Foals aged < 125 days, treated at a hospital in Ireland in 2007 or 2008 and presented for sale to a public auction recorded on a publicly accessible database were selected for inclusion in the study. The sales outcome of these subjects was compared to that of 6 controls for each subject, consisting of the 3 horses that were presented to the same sale immediately before and immediately after the subject. Results were controlled for the sale at which the animal presented and the sex of the subject and controls. RESULTS: Sixty-three subjects were presented to public auction: 19 at the foal sales, 39 at the yearling sales and 5 at the 2-year-old sales. Forty-five subjects were sold. There was no difference in the mean sales price (subjects Euros 38,207; controls Euros 35,026) or percentage of animals sold (subjects 71.4%; controls 66.4%) between subjects and controls. CONCLUSIONS: If Thoroughbred horses are presented for public auction following hospital treatment as a foal, there is no impact on sales outcome. POTENTIAL RELEVANCE: This information may help commercial breeders of Thoroughbred foals make informed decisions about treatment of their foals.


Asunto(s)
Enfermedades de los Caballos/terapia , Hospitalización/estadística & datos numéricos , Animales , Estudios de Casos y Controles , Comercio , Femenino , Enfermedades de los Caballos/economía , Caballos , Masculino
5.
Equine Vet Educ ; 24(8): 392-395, 2012 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32313388
6.
J Vet Intern Med ; 22(5): 1223-7, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-18691362

RESUMEN

REASONS FOR PERFORMING STUDY: Critical illness is associated with hyperglycemia in humans, and a greater degree and duration of hyperglycemia is associated with nonsurvival. Hypoglycemia is also seen in critically ill humans, and is associated with nonsurvival. This might also be true in the critically ill foal. OBJECTIVES: To investigate the association of blood glucose concentrations with survival, sepsis, and the systemic inflammatory response syndrome (SIRS). METHODS: Blood glucose concentrations at admission (515 foals) and 24 hours (159 foals), 36 hours (95), 48 hours (82), and 60 hours (45) after admission were analyzed. Logistic regression analyses were performed to investigate the association of glucose concentrations with survival, sepsis, a positive blood culture, or SIRS. RESULTS: 29.1% of foals had blood glucose concentrations within the reference range (76-131 mg/dL) at admission, 36.5% were hyperglycemic, and 34.4% were hypoglycaemic. Foals that did not survive to hospital discharge had lower mean blood glucose concentrations at admission, as well as higher maximum and lower minimum blood glucose concentrations in the 1st 24 hours of hospitalization, and higher blood glucose at 24 and 36 hours. Foals with blood glucose concentrations <2.8 mmol/L (50 mg/dL) or >10 mmol/L (180 mg/dL) at admission were less likely to survive. Hypoglycemia at admission was associated with sepsis, a positive blood culture, and SIRS. CONCLUSIONS AND POTENTIAL RELEVANCE: Derangements of blood glucose concentration are common in critically ill foals. Controlling blood glucose concentrations may therefore be beneficial in the critically ill neonatal foal, and this warrants further investigation.


Asunto(s)
Animales Recién Nacidos/sangre , Glucemia/análisis , Enfermedades de los Caballos/sangre , Animales , Enfermedad Crítica , Femenino , Caballos , Masculino
7.
J Vet Intern Med ; 22(5): 1210-5, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-18638020

RESUMEN

BACKGROUND: Norepinephrine increases arterial blood pressure but may have adverse effects on renal blood flow. Fenoldopam, a dopamine-1 receptor agonist, increases urine output in normotensive foals. The combination of norepinephrine and fenoldopam may lead to improved renal perfusion compared with an infusion of norepinephrine alone. The combined effects of these drugs have not been reported in the horse. HYPOTHESIS: Norepinephrine will alter the hemodynamic profile of foals without affecting renal function. Addition of fenoldopam will change the renal profile during the infusions without changing the hemodynamic profile. ANIMALS: Five conscious pony foals. METHODS: Each foal received norepinephrine (0.3 microg/kg/min), combined norepinephrine (0.3 microg/kg/min) and fenoldopam (0.04 microg/kg/min), and a control dose of saline in a masked, placebo-controlled study. Heart rate (HR), arterial blood pressure (direct), and cardiac output (lithium dilution) were measured, and systemic vascular resistance (SVR), stroke volume, cardiac index (CI), and stroke volume index were calculated. Urine output, creatinine clearance, and fractional excretion of electrolytes were measured. RESULTS: Norepinephrine and a combined norepinephrine and fenoldopam infusion increased arterial blood pressure, SVR, urine output, and creatinine clearance and decreased HR and CI compared with saline. The combination resulted in higher HR and lower arterial blood pressure than norepinephrine alone. CONCLUSIONS AND CLINICAL IMPORTANCE: Norepinephrine might be useful for hypotensive foals, because in normal foals, this infusion rate increases SVR without negatively affecting renal function (creatinine clearance increased). Fenoldopam does not provide additional benefit to renal function. These findings warrant further investigation.


Asunto(s)
Fenoldopam/administración & dosificación , Fenoldopam/farmacología , Hemodinámica/efectos de los fármacos , Caballos/fisiología , Norepinefrina/administración & dosificación , Norepinefrina/farmacología , Animales , Animales Recién Nacidos , Riñón/efectos de los fármacos , Vasoconstrictores/administración & dosificación , Vasoconstrictores/farmacología , Vasodilatadores/administración & dosificación , Vasodilatadores/farmacología
8.
Equine Vet J ; 40(1): 64-9, 2008 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-18083662

RESUMEN

REASON FOR PERFORMING STUDY: Neonatal foals succumb rapidly to hypovolaemic shock in comparison to mature horses; they do not consistently increase their heart rate in response to hypotension and respond differently to fluid administration. The hormonal responses to hypovolaemia in the horse and foal require investigation. HYPOTHESIS: The hormonal responses to hypovolaemia and fluid administration differ between mature and neonatal horses. METHODS: Five mature horses and 5 neonatal foals fulfilling predetermined criteria for hypovolaemia, were included in the study. A blood sample was taken at admission and after normalisation of fluid balance. These were analysed for plasma aldosterone, vasopressin (AVP) and atrial natriuretic peptide (ANP). Normally distributed variables were compared using the Student's t test and nonparametric data using the Mann-Whitney U test. RESULTS: ANP, AVP and aldosterone were higher before fluid resuscitation than after fluid resuscitation in mature horses. Aldosterone was higher before than after fluid resuscitation in foals, and was higher in foals both before and after fluid resuscitation than in mature horses. ANP was lower in mature horses after fluid resuscitation than in foals. No other comparisons were significantly different. CONCLUSIONS: The hormonal responses of the mature and neonatal horses are different during hypovolaemia and following fluid resuscitation. POTENTIAL RELEVANCE: The differences in the hormonal responses to hypovolaemia and fluid resuscitation may be important when considering fluid resuscitation of hypovolaemic horses and foals, and warrants further investigation.


Asunto(s)
Envejecimiento/sangre , Aldosterona/sangre , Factor Natriurético Atrial/sangre , Enfermedades de los Caballos/sangre , Hipovolemia/veterinaria , Vasopresinas/sangre , Animales , Animales Recién Nacidos , Líquidos Corporales/metabolismo , Femenino , Fluidoterapia/veterinaria , Enfermedades de los Caballos/terapia , Caballos , Hipovolemia/sangre , Hipovolemia/terapia , Masculino , Estadísticas no Paramétricas , Resultado del Tratamiento
9.
J Vet Intern Med ; 21(5): 1099-103, 2007.
Artículo en Inglés | MEDLINE | ID: mdl-17939570

RESUMEN

BACKGROUND: Hyperglycemia in critically ill humans is associated with increased glucose production and insulin resistance and is associated with death. This might also be true in horses presenting with acute abdominal disease. HYPOTHESIS: Throughout hospitalization, hyperglycemia will be common in adult horses presenting with acute abdominal disease. Hyperglycemia will be associated with a worse prognosis for survival to hospital discharge. ANIMALS: Two hundred sixty-nine adult horses with acute abdominal disease. METHODS: Observational retrospective study. Records were reviewed for 269 horses that had glucose data analysed and recorded at the time of hospital admission: 154 horses had a first sample after admission; 110 horses at 24 hours after admission; 74 horses at 36 hours after admission; and 49 horses at 48 hours after admission. Logistic regression analyses were performed to investigate the association of glucose concentrations with survival, in addition to the association of glucose concentrations with surgical, small intestinal, strangulating lesions, and lesions requiring a resection. RESULTS: Of 269 horses presenting with acute abdominal disease, 50.2% had blood glucose concentrations greater than the reference range (75.6-131.4 mg/dL); 0.4%, below the reference range; and 49.4%, within the reference range at admission. Of 269 horses, 2.3% had blood glucose concentrations below the reference range at some point during the first 48 hours of hospitalization, all of which had strangulating intestinal lesions. Horses that did not survive to hospital discharge had a higher mean blood glucose concentration at admission; at the first sample after admission; at 24, 36, and 48 hours after admission; and higher maximum and minimum blood glucose concentrations in the first 24 hours after admission. CONCLUSIONS AND CLINICAL IMPORTANCE: Derangements of blood glucose concentration are common in horses with acute abdominal disease. Hyperglycemia is much more common than hypoglycemia in these animals. Hyperglycemia in the first 48 hours of hospitalization is associated with a worse prognosis for survival to hospital discharge.


Asunto(s)
Glucemia/metabolismo , Enfermedades de los Caballos/sangre , Hiperglucemia/veterinaria , Enfermedades Intestinales/veterinaria , Animales , Femenino , Enfermedades de los Caballos/patología , Caballos , Hiperglucemia/sangre , Hiperglucemia/patología , Enfermedades Intestinales/sangre , Enfermedades Intestinales/patología , Masculino , Estudios Retrospectivos , Análisis de Supervivencia
10.
Equine Vet J ; 39(1): 84-9, 2007 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-17228602

RESUMEN

REASONS FOR PERFORMING STUDY: Treatment for bacteraemia in foals must be started before the identity of the causative organism is known. Information aiding selection of effective antimicrobials should improve outcome. OBJECTIVES: To describe differences in clinical and clinicopathological data and outcome in foals with bacteraemia due to different classes of bacteria. METHODS: Records of foals with a positive blood culture, age < 10 days and presenting to a university hospital 1995-2004, were reviewed. Bacterial culture results, subject details, historical information, physical examination findings at admission and clinicopathological data generated during the first 48 h of hospitalisation were analysed. Results from foals with Gram-positive or Gram-negative organisms, single or mixed organism bacteraemias, and with bacteraemia due to 3 commonly isolated organisms were compared. RESULTS: Eighty-five foals met the inclusion criteria. Gram-negative organisms (n = 59) Gram-positive organisms (n = 13) or multiple organisms (n = 19) were cultured from individual foals. Foals with Gram-negative bacteraemia had lower total white blood cell and lymphocyte counts at admission than did those from which only Gram-positive bacteria were cultured. Mixed organism bacteraemia was associated with tachycardia, increased serum concentrations of sodium, chloride and urea nitrogen, acidosis, respiratory distress, recumbency on admission and nonsurvival. Actinobacillus spp. infections were associated with leucopenia, neutropenia, lymphopenia and depression on hospital admission. CONCLUSIONS AND POTENTIAL RELEVANCE: Recognising particular patterns of clinical and clinicopathological findings associated with infection with specific groups of bacteria may, in the future, aid antimicrobial selection and influence prognosis in bacteraemic foals.


Asunto(s)
Bacteriemia/veterinaria , Bacterias Gramnegativas/clasificación , Infecciones por Bacterias Gramnegativas/veterinaria , Bacterias Grampositivas/clasificación , Infecciones por Bacterias Grampositivas/veterinaria , Enfermedades de los Caballos/microbiología , Animales , Animales Recién Nacidos , Antibacterianos/uso terapéutico , Bacteriemia/diagnóstico , Bacteriemia/tratamiento farmacológico , Bacteriemia/microbiología , Diagnóstico Diferencial , Bacterias Gramnegativas/aislamiento & purificación , Infecciones por Bacterias Gramnegativas/sangre , Infecciones por Bacterias Gramnegativas/diagnóstico , Infecciones por Bacterias Gramnegativas/microbiología , Bacterias Grampositivas/aislamiento & purificación , Infecciones por Bacterias Grampositivas/sangre , Infecciones por Bacterias Grampositivas/diagnóstico , Infecciones por Bacterias Grampositivas/microbiología , Enfermedades de los Caballos/sangre , Enfermedades de los Caballos/diagnóstico , Enfermedades de los Caballos/tratamiento farmacológico , Caballos , Recuento de Leucocitos/veterinaria , Recuento de Linfocitos/veterinaria , Análisis de Supervivencia , Resultado del Tratamiento
11.
J Vet Intern Med ; 20(6): 1437-42, 2006.
Artículo en Inglés | MEDLINE | ID: mdl-17186862

RESUMEN

BACKGROUND: Norepinephrine is a potent vasopressor that increases arterial blood pressure but may have adverse effects on renal blood flow. The combination of norepinephrine and dobutamine may lead to improved renal perfusion compared to an infusion of norepinephrine alone. The effects of these drugs in the normotensive neonatal foal have not been reported. HYPOTHESIS: Norepinephrine increases arterial blood pressure. Adding dobutamine to a norepinephrine infusion will change the renal profile during the infusions without changing the arterial blood pressure. ANIMALS: Eight conscious Thoroughbred foals were used in this study. METHODS: Each foal received norepinephrine (0.1 microg/kg/min), combined norepinephrine (0.1 microg/kg/min) and dobutamine (5 microg/kg/min), and a control dose of saline in a masked, placebo-controlled study. Heart rate, arterial blood pressure (direct), and cardiac output (lithium dilution) were measured, and systemic vascular resistance, stroke volume, cardiac index, and stroke volume index were calculated. Urine output, creatinine clearance, and fractional excretion of sodium, potassium, and chloride were measured. RESULTS: Norepinephrine and a combined norepinephrine and dobutamine infusion increased arterial blood pressure and systemic vascular resistance and decreased heart rate and cardiac index as compared to saline. The combination resulted in higher arterial pressure than norepinephrine alone. There was no significant difference in urine output, creatinine clearance, or fractional excretion of electrolytes with either infusion as compared to saline. CONCLUSIONS AND CLINICAL IMPORTANCE: These data suggest that norepinephrine and a combined norepinephrine and dobutamine infusion cause unique hemodynamic effects without affecting indices of renal function, and this effect warrants further investigation.


Asunto(s)
Dobutamina/farmacología , Caballos/fisiología , Riñón/efectos de los fármacos , Norepinefrina/farmacología , Simpatomiméticos/farmacología , Animales , Animales Recién Nacidos/fisiología , Presión Sanguínea/efectos de los fármacos , Creatinina/orina , Combinación de Medicamentos , Electrólitos/orina , Frecuencia Cardíaca/efectos de los fármacos , Infusiones Intravenosas/veterinaria , Riñón/fisiología , Pruebas de Función Renal/veterinaria , Resistencia Vascular/efectos de los fármacos
12.
Equine Vet J ; 37(1): 53-9, 2005 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-15651735

RESUMEN

REASONS FOR PERFORMING STUDY: Blood lactate concentration has been shown to be a useful clinical indicator in human patients, but has not been formally investigated in critically ill foals. OBJECTIVE: To investigate the association of blood lactate with hospital survival, markers of cardiovascular status, metabolic acid base status, sepsis and systemic inflammatory response syndrome (SIRS). METHODS: A database containing clinical, haematological, plasma biochemical and hospital outcome data on neonatal foals referred to an intensive care unit in 2000-2001 was analysed. Seventy-two foals for which arterial lactate was measured at admission were included in the study. RESULTS: Sixty-one foals had an admission lactate concentration > 2.5 mmol/l. Admission lactate was statistically associated with hospital survival, mean arterial pressure, blood creatinine concentration, bacteraemia, anion gap, lactate concentration at 18-36 h after admission and evidence of SIRS, but not with packed cell volume or heart rate. Lactate at 18-36 h was also associated with survival and evidence of SIRS. Anion gap, base excess, base excess due to unidentified anions (BEua), simplified strong ion gap or bicarbonate correctly classified foals for presence of hyperlactaemia (> 5 mmol/l) in < or = 80% of animals. CONCLUSIONS: Admission blood lactate gives important prognostic information. Lactate should be measured rather than assumed from the anion gap, base excess, BEua, simplified strong ion gap or bicarbonate. POTENTIAL RELEVANCE: Blood lactate concentrations at admission are clinically relevant in neonatal foals and warrant further investigation. This should include the clinical value of measuring changes in lactate in response to treatment.


Asunto(s)
Enfermedades de los Caballos/sangre , Ácido Láctico/sangre , Síndrome de Respuesta Inflamatoria Sistémica/veterinaria , Equilibrio Ácido-Base , Animales , Animales Recién Nacidos , Análisis de los Gases de la Sangre/veterinaria , Enfermedad Crítica , Enfermedades de los Caballos/diagnóstico , Enfermedades de los Caballos/mortalidad , Caballos , Valor Predictivo de las Pruebas , Sepsis/sangre , Sepsis/diagnóstico , Sepsis/mortalidad , Sepsis/veterinaria , Índice de Severidad de la Enfermedad , Análisis de Supervivencia , Síndrome de Respuesta Inflamatoria Sistémica/sangre , Síndrome de Respuesta Inflamatoria Sistémica/diagnóstico , Síndrome de Respuesta Inflamatoria Sistémica/mortalidad , Factores de Tiempo
13.
Vet Rec ; 153(15): 457-62, 2003 Oct 11.
Artículo en Inglés | MEDLINE | ID: mdl-14584575

RESUMEN

The diagnostic and prognostic value of nuclear scintigraphy with technetium-99m-labelled hexamethyl-propyleneamine oxime-labelled leucocytes was assessed in 17 horses with weight loss due to gastrointestinal malabsorption by comparing the results with the results obtained from 13 normal control horses. Intestinal uptake of activity was detected in 12 of the 17 cases but none of the control horses. The technique was therefore specific for intestinal pathology, but failed to detect some horses that might have had intestinal pathology. No indications of the horses' specific pathology were obtained, and their prognosis or response to treatment could not be predicted.


Asunto(s)
Enfermedades de los Caballos/diagnóstico por imagen , Síndromes de Malabsorción/veterinaria , Radiofármacos , Exametazima de Tecnecio Tc 99m , Animales , Estudios de Casos y Controles , Femenino , Prueba de Tolerancia a la Glucosa/veterinaria , Enfermedades de los Caballos/sangre , Caballos , Leucocitos/fisiología , Síndromes de Malabsorción/diagnóstico por imagen , Masculino , Valor Predictivo de las Pruebas , Cintigrafía/normas , Cintigrafía/veterinaria
14.
Equine Vet J ; 34(6): 598-601, 2002 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-12358000

RESUMEN

Knowledge of cardiac output is expected to help guide the treatment of hypotension associated with critical illness and/or anaesthesia in neonatal foals. However, a practical and safe method of measuring cardiac output has not been described for the foal. Lithum dilution, a new method of cardiac output determination not requiring cardiac catheterisation, has recently been reported in mature horses. We compared this method to thermodilution in isoflurane-anaesthetised foals age 30-42 h and found good agreement between the 2 methods in a range of cardiac outputs 5.4-20.4 l/min. The lithium dilution technique is a practical and reliable method of measuring cardiac output in anaesthetised neonatal foals, and warrants investigation in critically ill conscious foals.


Asunto(s)
Animales Recién Nacidos/fisiología , Gasto Cardíaco , Enfermedades de los Caballos/diagnóstico , Caballos/fisiología , Hipotensión/veterinaria , Litio , Animales , Cateterismo Cardíaco/veterinaria , Enfermedad Crítica , Femenino , Hipotensión/diagnóstico , Técnicas de Dilución del Indicador/veterinaria , Masculino , Termodilución/métodos , Termodilución/veterinaria
15.
Eur J Immunol ; 28(3): 1034-9, 1998 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-9541599

RESUMEN

Endogenous superantigens encoded by mouse mammary tumor viruses associate with MHC class II and interact with T cells bearing particular V beta gene segments. H-2E is more efficient at presentation than H-2A, indeed Aq has not been shown to be capable of presenting endogenous superantigens. Atypically, the superantigen vSAG-3 encoded by Mtv-3 is presented efficiently in non-obese diabetic (H-2g7) mice by H-2A; we have examined the independent contributions of vSAG-3 and Ag7 to this process. Ag7 was not found to have a more general ability to efficiently present endogenous superantigens other than Mtv-3. Examination of Mtv-3-mediated thymic deletion of V beta 3+ thymocytes in the presence of H-2q additionally demonstrated the efficient presentation of vSAG-3 by Aq. Interaction of vSAG-3 with Aq and Ag7 is likely to reflect the unique sequence of Mtv-3 within the second polymorphic region previously implicated in MHC class II binding. The demonstration that mouse endogenous superantigens can be presented by a wider range of MHC haplotypes than previously thought is further evidence for their immunological impact on the mouse population.


Asunto(s)
Antígenos Virales/metabolismo , Antígenos H-2/metabolismo , Virus del Tumor Mamario del Ratón/inmunología , Superantígenos/metabolismo , Animales , Células Presentadoras de Antígenos/inmunología , Haplotipos , Complejo Mayor de Histocompatibilidad , Glicoproteínas de Membrana/metabolismo , Ratones , Ratones Endogámicos NOD/inmunología , Receptores de Antígenos de Linfocitos T alfa-beta/análisis , Subgrupos de Linfocitos T/inmunología
16.
Int Immunol ; 8(9): 1413-20, 1996 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-8921419

RESUMEN

The site of negative selection in the thymus has been inferred from a range of different experiments. Analysis of thymic deletion of V beta 5+, V beta 11+ or V beta 17a+ cells in H-2E transgenic mice led to the theory that negative selection occurs predominantly in the medulla (specifically, through presentation by medullary dendritic cells). Other experiments investigated whether transgenic TCR are deleted at the double-positive (DP) or single-positive stage following encounter with peptide ligand: by flow cytometric analysis deletion is generally found to occur at the DP thymocyte stage and as these cells are found predominantly in the cortex, it has been inferred that this is the key site of negative selection. The visualization of apoptotic thymocytes in situ has recently been reported for specific examples of negative selection. Using a panel of TCR transgenic lines in which negative selection occurs at different stages of thymocyte development, we have used TUNEL staining to analyse the anatomical sites of thymocyte apoptosis. For the first time we have been able to compare directly the sites of deletion induced by the endogenous cognate peptides or by endogenous superantigen. We show that generalization from the medullary deletion of V beta 5+, V beta 11+ or V beta 17a+ cells by the endogenous superantigens Mtv 8 and 9 from limited examples of cortical deletion by exogenous peptide administered to TCR transgenic mice is over-simplified. Apoptotic thymocytes in mice lacking Mtv superantigens are indeed localized in the cortex. However, when deletion is induced by cognate self peptide, apoptosis can occur in the cortex, the medulla or at the junction between the two.


Asunto(s)
Autoantígenos/inmunología , Supresión Clonal , Superantígenos/inmunología , Timo/inmunología , Animales , Apoptosis , Técnica del Anticuerpo Fluorescente Indirecta , Reordenamiento Génico de la Cadena beta de los Receptores de Antígenos de los Linfocitos T , Ratones , Ratones Endogámicos CBA , Ratones Transgénicos , Receptores de Antígenos de Linfocitos T alfa-beta , Timo/ultraestructura
17.
J Clin Microbiol ; 30(1): 59-62, 1992 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-1310333

RESUMEN

Foal fecal group A rotavirus strains were characterized by electropherotype, serotype, and subgroup and shown to be distinctly different from rotaviruses of other mammals. Of 86 strains that were electropherotyped, 98% had similar profiles, with gene segments 3 and 4 close together and segments 7, 8, and 9 widely spaced. Of 70 strains that had sufficient detectable VP7 antigen to be serotyped by enzyme-linked immunosorbent assays (ELISAs), 63% were serotype G3 (39% were subtype G3A and 24% were subtype G3B), 4% were serotype G13, and 33% were untypeable. Serotypes G1, G2, G4, G5, G6, G9, G10, and G14 were not detected, although G5 and G14 strains have been identified among cultivable equine strains. Of 50 strains that had sufficient detectable VP6 antigen to be subgrouped by ELISAs, only 12% were able to be assigned to either subgroup I or II, with the remaining 88% belonging to neither subgroup.


Asunto(s)
Diarrea/veterinaria , Enfermedades de los Caballos/microbiología , Infecciones por Rotavirus/veterinaria , Rotavirus/clasificación , Animales , Diarrea/microbiología , Ensayo de Inmunoadsorción Enzimática , Heces/microbiología , Caballos , Rotavirus/inmunología , Rotavirus/aislamiento & purificación , Infecciones por Rotavirus/microbiología , Serotipificación
18.
Br Vet J ; 147(5): 444-54, 1991.
Artículo en Inglés | MEDLINE | ID: mdl-1959016

RESUMEN

The pre-slaughter handling, behaviour and blood composition of beef cattle at slaughter was studied in a commercial slaughterhouse. The main problems identified were the routine use of driving instruments and delays caused by stoppages in the slaughter line. The plasma concentration of cortisol at the time of slaughter was positively correlated with the time spent standing still and with the time spent in the pre-stun pen. The plasma activity of creatine kinase was positively correlated with the time spent in the race, but no correlations between creatine kinase and physical activity in the race were found. The plasma concentration of glucose was positively correlated with the time spent trotting and the number of times that struggling occurred. The proportions of cattle struggling, vocalizing and defaecating were greatest when they were confined in the race and pre-stun pen. Cattle kept overnight in the lairage had a greater concentration of free fatty acids at the time of slaughter than those slaughtered on the day of arrival. There were no other significant differences in either the blood composition or the handling and behaviour of cattle kept overnight in the lairage, compared with those slaughtered on the day of arrival. Some of the handling problems observed were caused by incorrect design of the handling facilities. There should be some means of removing cattle from a race if delays are encountered and some means of handling the cattle in the race other than by using an electrical goad. The optimal dimensions of races and passageways to prevent crowding and turning around should be assessed at the design stage. Non-slip floors are essential.


Asunto(s)
Mataderos/normas , Conducta Animal , Bovinos , Animales , Glucemia/análisis , Bovinos/sangre , Creatina Quinasa/sangre , Ácidos Grasos no Esterificados/sangre , Femenino , Hidrocortisona/sangre , Masculino
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