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Biomedical subjects

P D Constable

Publications and source records attributed to P D Constable.

At least 55 records · Page 3Linked to original sources
PubMed1996

Bovine uterine torsion: 164 hospital referral cases.

Uterine torsion is more common in the cow than any other domestic species. The etiopathogenesis of the condition remains open to speculation. Available hospital referral records of bovine uterine torsions (n = 164) were collated, and additional comparisons for season, age and breed were made using the VDMP data base of 24 North American veterinary schools. There was no effect of season. Brown Swiss cows were at a significantly higher risk (P = 0.0001), while Hereford, Angus, and Jersey cows were at a lower risk for uterine torsion when compared with Holstein-Friesian cows, the largest breed population (P = 0.01). Most cows (81%) were at term. Clinical signs of torsion included fever (23%), tachycardia (93%), tachypnea (94%), straining (23%), anorexia (18%) and vaginal discharge (13%). In 34% of the cases the torsion was precervical, with no vaginal involvement being noted. The severity of the torsion was predominately 180 to 270 degrees (57%) and 271 to 360 degrees (22%). Counter-clockwise torsion was present in 63% of the cases. Vaginal delivery was possible after manual correction (20%) or rolling of the cow (18%). Cesarean section was performed immediately in 35% of the cases, after failed detorsion attempts in 7%, and due to failure of the cervix to dilate following successful correction of the torsion in 20%. Calf birth weights exceeded breed means in 89% of the cases, and a significantly greater proportion (63%) of the fetuses were male. Fetal survival rate was 24% (14% of dead fetuses were emphysematous), and the cow survival rate was 78% (10% were euthanized). The fetal membrane retention rate was 57%. It was found that large term fetuses appear to predispose a cow to uterine torsion.

Journal Article↗
PubMed1996

Factors associated with finishing status for dogs competing in a long-distance sled race.

OBJECTIVE: To determine whether selected factors were associated with finishing status in a long-distance sled dog race. DESIGN: Prospective, observational study. ANIMALS: 248 dogs participating in the 1994 Iditarod trail sled race that were members of 13 teams that finished the race. Dogs were not selected randomly, but were members of teams that were easily accessible for examination before the race. The proportion of teams that were examined that finished the race (14/17) was similar to the proportion of teams that were not examined that finished the race (36/41). PROCEDURE: Age, sex, body conformation (weight, length, and thoracic width and circumference), cardiac variables (heart rate, natural logarithm of heart period variance, PR interval, QRS duration, QT index, R wave amplitude in leads II and V3, mean electrical axis, presence of cardiac arrhythmias suggestive of myocardial disease), and athletic ranking as assessed by the musher were compared between dogs that finished the race (n = 128) and dogs that did not finish (n = 120). RESULTS: The only factor found to differ significantly (P < 0.05) between finishers and nonfinishers was athletic ranking as assessed by the musher. Athletic rank and QRS duration or QRS duration normalized for body weight were identified by means of logistic regression as variables associated (P < 0.15) with finishing status. There was a significant (P < 0.0001), but weak (R2 = 0.18), linear relationship between race time and mean QRS duration for each team. CLINICAL IMPLICATIONS: Athletic ranking as assessed by the musher was the most important of the studied variables in determining finishing status, whereas age, sex, body conformation, and body weight were unimportant. Duration of the QRS was of minor importance in determining finishing status.

Animals↗
PubMed1996

ECG of the month.

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Anesthetics, Inhalation↗
PubMed1996

Cardiovascular effects of fumonisins in swine.

Fumonisins, mycotoxins produced by Fusarium moniliforme, induce hepatic damage and acute lethal pulmonary edema in swine. We examined the cardiovascular effects of short-term fumonisin exposure in anesthetized and conscious male cross-bred pigs weighing 30-36 kg. Culture material containing fumonisins at < or = 20 mg/kg/day (fumonisin B1 and B2 backbone) was added to the feed of treated pigs (n = 5) for 7 days, while control pigs (n = 5) were fed a diet free of fumonisins. On Day 8, pigs were anesthetized with halothane and instrumented with Swan-Ganz catheters to facilitate hemodynamic measurements. Mean pulmonary artery pressure, central venous pressure, heart rate, cardiac output, and electrocardiographic variables were recorded and stroke volume was calculated. All measurements were repeated at least 18 hr after recovery from anesthesia. Pigs fed fumonisins had a significant increase in mean pulmonary artery pressure, accompanied by decreased heart rate, cardiac output, and mixed venous oxygen tension. The electrocardiogram was normal, and there was no evidence of pulmonary edema formation either histologically or by altered lung wet/dry weights. This study suggests that pulmonary hypertension caused by hypoxic vasoconstriction may be associated with the pulmonary edema observed in fumonisin toxicity.

Animals↗
PubMed1996

Cardiovascular responses to short-term fumonisin exposure in swine.

The cardiovascular effects of the mycotoxin fumonisin were examined in male cross-bred pigs fed 20 mg/kg of fumonisin-containing culture material for 7 days. On Day 8, pigs were anesthetized with halothane and surgically catheterized. Cardiovascular measurements and blood gas analyses were obtained during halothane anesthesia and 18 hr after recovery from anesthesia. Pigs fed fumonisin had significant (p < 0.05) decreases in maximal rate of change of left ventricular pressure, heart rate, cardiac output, and mean aortic pressure, a significant increase in mean pulmonary artery pressure and pulmonary vascular resistance, and no change in left ventricular end-diastolic pressure, pulmonary wedge pressure, and central venous pressure. Treated pigs also had significant decreases in both arterial and mixed venous blood O2 tension, and systemic oxygen delivery, but significantly increased oxygen consumption and oxygen extraction ratio. These results suggest that fumonisin increases oxygen consumption and is a negative inotropic and chronotropic agent in pigs. Because fumonisin is a naturally occurring inhibitor of the enzyme sphingosine N-acyltransferase, thereby increasing sphingosine concentrations in vivo, we speculate that the observed cardiovascular effects were mediated in part by a fumonisin-induced increase in tissue sphingosine concentrations.

Administration, Oral↗
PubMed1996

Use of hypertonic saline-dextran solution to resuscitate hypovolemic calves with diarrhea.

OBJECTIVE: To determine effectiveness of a new and practical method for fluid resuscitation of dehydrated diarrheic calves. DESIGN: Animals randomly allocated to 4 groups with appropriate controls. ANIMALS: 16 healthy male dairy calves, 3 to 6 days old. PROCEDURE: After instrumentation and recording baseline data, diarrhea and hypovolemia were induced by administering milk replacer (33 ml/kg of body weight) and isotonic sucrose solution (2 g of sucrose in 19.5 ml of water/kg, PO) every 8 hours, and furosemide (2 mg/kg, IM) every 4 to 8 hours. Administration of milk replacer and furosemide was discontinued when calves became 6% dehydrated. Calves were then randomly allocated as: control (no treatment); hypertonic saline-dextran (HSD) solution (4 ml/kg, 2,400 mOsm/L NaCl in 6% dextran-70, administered once over 4 minutes, IV); isotonic alkalinizing oral electrolyte solution (55 ml/kg, PO, q 8 h); and HSD-oral electrolyte solution (combination of HSD and oral treatments). Calves were monitored for 24 hours after treatment. RESULTS: Significant changes included moderate dehydration (8% body weight), marked lethargy, decreased cardiac output and plasma volume, and increased blood lactate concentration, hematocrit, and serum concentrations of albumin, creatinine, sodium, and phosphate. Control calves continued to be lethargic and dehydrated, with significant increases in hematocrit and serum creatinine concentration. Increase in cardiac output and plasma volume was transient in the HSD group and waned by 2 to 8 hours after treatment. Oral electrolyte fluid administration caused slow and sustained increase in cardiac output and plasma volume, and decrease in heart rate, blood lactate concentration, and hematocrit. Combined administration of HSD-oral electrolyte solution caused immediate and sustained increase in cardiac output and plasma volume, and decrease in heart rate, blood lactate concentration, and hematocrit. CONCLUSIONS AND CLINICAL RELEVANCE: Treatment of hypovolemic diarrheic calves with IV HSD and oral electrolyte solution is superior to administration of either solution alone.

Animals↗
PubMed1996

Effects of fumonisin-containing culture material on pulmonary clearance in swine.

OBJECTIVE: To determine the potential effects of feeding tumonisin-containing culture material on the pulmonary clearance of blood-borne particulates and bacteria in swine. ANIMALS: 21 healthy male pigs randomly assigned to control and treated groups. PROCEDURE: Control pigs were fed a standard grower ration while culture material containing fumonisins (20 mg of hydrolyzed fumonisin B1/kg of body weight/d) was added to the feed of treated pigs for 7 days. On day 8, pigs were anesthetized with halothane and catheterized, using a sterile cut-down procedure. 18 hours after recovery from anesthesia, Monastral Blue or Pseudomonas aeruginosa was infused into the right atrium of treated and control pigs for 30 minutes and pulmonary clearance was determined. RESULTS: Pigs that were fed fumonisin-containing culture material had a significantly (P < 0.05) decreased ability to clear Monastral Blue and P aeruginosa. Ultrastructural examination of the lung indicated that uptake of copper pigment by pulmonary intravascular macrophages was decreased in treated pigs. CONCLUSIONS AND CLINICAL RELEVANCE: Fumonisins, even when fed to pigs at sub-lethal concentrations, can inhibit pulmonary intravascular macrophages from removing particulate matter and bacteria from the circulation, thus potentially predisposing swine to infectious disease.

Animal Feed↗
PubMed1995

Effect of hypertonic saline solution on left ventricular afterload in normovolumic dogs.

The effects of hypertonic saline solution (HSS) and hyperosmotic dextrose (HD; 2,400 mosm/L, 4 ml/kg of body weight) on left ventricular afterload were determined in normovolumic, chloralose-anesthetized, autonomically blocked dogs (n = 8). Solutions were infused IV over 3 minutes. Left ventricular afterload was assessed by use of a dual-tipped micromanometer catheter with an electromagnetic fluid-velocity sensor located in the ascending aorta, and the impedance spectrum was calculated after Fourier analysis of signal-averaged aortic pressure and flow signals. Hypertonic saline solution and HD decreased peripheral resistance, reflection coefficient at zero frequency, and frequency of the first zero crossing of the phase angle for 3 to 5 minutes after either fluid was administered. Characteristic impedance was not altered by HSS or HD. These impedance spectrum changes indicate transient vasodilatation and afterload reduction. We conclude that the vascular effect of an ionic hyperosmotic solution (HSS) is similar to that of a nonionic hyperosmotic solution (HD), and that HSS and HD transiently decrease afterload in normovolumic dogs. The duration of the afterload reduction after HSS administration appeared to be too short to be of great clinical benefit.

Animals↗
PubMed1994

Hypertonic saline is a negative inotropic agent in normovolumic dogs.

The inotropic effects of hypertonic saline (HS) and hyperosmotic dextrose (HD; 2,400 mosmol/l, 4 ml/kg) were determined in normovolumic, chloralose-anesthetized, intact (n = 14) and autonomically blocked (n = 8) dogs. Solutions were infused intravenously over 3 min. HS and HD rapidly increased preload in both intact and autonomically blocked dogs, as assessed by significant (P < 0.05) increases in plasma volume, end-diastolic volume, and end-diastolic pressure. In intact dogs, HS produced a nonsignificant decrease in end-systolic elastance (Ees) and a nonsignificant increase in the maximal rate of change of left ventricular pressure (dP/dtmax) and cardiac output, whereas HD produced a significant increase in Ees, dP/dtmax, and cardiac output. In autonomically blocked dogs, HS significantly decreased Ees and significantly increased dP/dtmax but did not alter cardiac output, whereas HD significantly increased Ees, dP/dtmax, and cardiac output. We conclude that in normovolumic animals, HS is a negative inotropic agent, HD is a positive inotropic agent, and the in vivo effect of an ionic hyperosmotic agent (HS) differs from that of a nonionic hyperosmotic agent (HD).

Animals↗
PubMed1994

Athletic heart syndrome in dogs competing in a long-distance sled race.

The cardiac effects of endurance training were evaluated by cardiac auscultation and electrocardiographic examination of 48 heavily trained sled dogs (3,000-5,000 km of training), 18 lightly trained sled dogs (300-800 km of training), 19 untrained sled dogs, and 14 mongrel dogs. A grade I-II/VI early- to midsystolic cardiac murmur was auscultated with increasing frequency as training level increased. The QRS duration (66.1 +/- 7.4 ms) and QT interval (236 +/- 20 ms) were significantly (P < 0.05) longer in heavily trained sled dogs than in mongrel dogs (QRS, 60.6 +/- 4.6; QT, 219 +/- 11 ms). A long QT interval (> 250 ms) was observed in 8 (16.7%) heavily trained dogs but not in the other groups. A significant rightward shift in the mean electrical axis of ventricular depolarization in the frontal plane was observed in heavily trained sled dogs. The auscultatory and electrocardiographic findings in heavily trained sled dogs were remarkably similar to those reported in elite human endurance athletes, suggesting that endurance-trained sled dogs provide a naturally occurring model for the athletic heart syndrome.

Animals↗
PubMed1993

Small-intestinal volvulus in cattle: 35 cases (1967-1992).

Medical records of 35 cattle with small-intestinal volvulus were reviewed. Surgical correction was performed on 32 cattle, and 17 of these cattle were discharged from the hospital. Mean duration of clinical signs for survivors was not significantly different from that for nonsurvivors, and the most commonly recorded clinical signs were abdominal pain, anorexia, lethargy, abdominal distention, and dehydration. Physical examination of cattle with intestinal volvulus revealed tachycardia, tachypnea, and normothermia. Rectal examination findings included distended small intestine, scant feces or mucus, and tight bands coursing dorsoventrally in the middle portion of the abdomen. Clinicopathologic testing revealed azotemia, hypocalcemia, hyperglycemia, and leukocytosis with a left shift. Nonsurvivors had significantly lower mean preoperative venous blood pH and mean base excess and higher mean serum potassium concentration than did survivors. A diagnosis of volvulus of the entire small intestine was made during surgery in 25 cattle, whereas volvulus of the distal jejunum and ileum was diagnosed during surgery in 7 cattle. Survival rate following surgical correction of volvulus of the entire small intestine (44%) was not significantly different from survival rate following surgical correction of volvulus of the distal jejunum and ileum (86%). However, survival rate for dairy cattle (63%) was significantly higher than survival rate for beef cattle (22%). To determine potential risk factors for the development of small-intestinal volvulus, epidemiologic data from cattle admitted to veterinary teaching hospitals throughout North America were collected by searching records entered into the Veterinary Medical Data Base.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Femoral and tibial fractures in a newborn calf after transplacental infection with bovine viral diarrhoea virus.

A one-week-old Brown Swiss calf had fractures of the metaphyseal regions of the left femur and right tibia, and a generalised, severe derangement of osteogenesis. Alternating zones of sclerosis and radiolucency in the metaphysis of all the long bones was visible radiographically. A histopathological examination revealed a segmental disruption of trabecular modelling, with subsequent fracture. Immunohistochemistry using a monoclonal antibody for bovine viral diarrhoea (BVD) virus revealed abundant viral antigen in the pituitary gland, hypothalamus and thyroid gland. Intestinal tissue was positive on fluorescent antibody testing for the virus. The lesions indicate that transplacental infection with BVD virus can result in severe skeletal abnormalities and fractures.

Animals↗
PubMed1992

Abomasal luminal pressure in cattle with abomasal volvulus or left displaced abomasum.

The abomasal luminal pressure was determined during surgery in 54 dairy cows with abomasal volvulus (AV) and another 50 dairy cows with left displaced abomasum. The luminal pressure was high in all cattle with AV and 49 (98%) cattle with left displaced abomasum. Luminal pressure was significantly higher in cattle with AV (median, 11.7 mm of Hg; range, 4.1 to 32.4 mm of Hg) than cattle with left displaced abomasum (median, 8.7 mm of Hg; range, 3.5 to 20.7 mm of Hg). Among cattle with AV, abomasal luminal pressure was significantly higher in cattle that died or were sold for slaughter following surgery (median, 20.6 mm of Hg; n = 8) than in cattle that were retained in the herd (median, 11.0 mm of Hg; n = 46). The luminal pressure was weakly correlated with the preoperative serum alkaline phosphatase activity but not correlated with duration of inappetence before surgery. Calculation of likelihood ratios and construction of a response operating characteristic curve for cattle with AV indicated that a cut-off value of 16 mm of Hg for luminal pressure optimized the distribution of cattle into productive and nonproductive groups. The sensitivity, specificity, positive predictive value, and negative predictive value of a luminal pressure < 16 mm of Hg in predicting a productive outcome were 0.83, 0.75, 0.95, and 0.43, respectively.

Abomasum↗
PubMed1992

Intramedullary pinning of femoral diaphyseal fractures in neonatal calves: 12 cases (1980-1990).

Medical records of 12 calves less than or equal to 1 month old, with fracture of the femoral diaphysis, were reviewed. Ten calves were within 1 week of birth at the time of diagnosis. Open reduction was accomplished by use of a lateral approach. Retrograde intramedullary pinning was accomplished in all calves, using 2 (n = 4 calves) or 3 (n = 8 calves) pins. Cerclage wire was used to supplement fixation in 7 calves. A closed continuous suction drain was placed along the lateral aspect of the femur in every calf. Postsurgical complications included seroma formation over the middle gluteal musculature (n = 5 calves), pin migration (n = 6 calves), and osteomyelitis (n = 1 calf). Pin migration was observed in 4 calves that had been treated with nonthreaded trochar point pins. Fractures in 10 of 12 calves (83%) were considered to have healed satisfactorily. One calf was euthanatized because of septic osteomyelitis of the femur. One calf was euthanatized because of persistent lameness and pin migration. Pins were removed in 8 of 12 calves (67%) between the 13th and 90th postoperative days. Results of this study indicate that application of intramedullary pins may be a useful solution for management of femoral diaphyseal fracture in young calves.

Animals↗
PubMed1992

Cryptorchidism in North American cattle: breed predisposition and clinical findings.

The authors analyzed data collected over 26 years from 143 cryptorchid bulls admitted to 23 North American veterinary schools. Breed was found to be a risk factor. The medical records of 41 cryptorchid cattle were also obtained, and the physical examination findings, method of diagnosis, and surgical management were recorded. Polled Hereford and Shorthorn cattle were at significantly greater risk for cryptorchidism; however, polled cattle were not at an increased risk for cryptorchidism. Cryptorchidism was most commonly diagnosed by external palpation of the superficial inguinal rings and by palpation per rectum. Unilateral cryptorchidism appears to be more common than bilateral cryptorchidism. The incidence of cryptorchidism was 69% for the left testis and 31% for the right testis. Sixty-six percent of the retained testes were located in the inguinal canal. Cryptorchidectomy was performed through an inguinal, paramedian or flank approach in 26 bulls. Cryptorchidism appears to be rare in bovine bulls admitted to North American veterinary schools, with 1.7 cases per 1,000 bull admissions. We suggest that cryptorchidism be considered an inherited trait in the Shorthorn and Polled Hereford breeds.

Journal Article↗
PubMed1992

Prophylactic low dose heparin anticoagulant therapy in patients with spinal cord injuries: a retrospective study.

A retrospective study was performed of 100 consecutive acute traumatic spinal injury patients with neurological deficit admitted to the Yorkshire regional spinal injuries centre prior to May 1990. Ninety-seven of these patients received prophylactic low dose subcutaneous heparin and 3 patients were excluded because of noted complications. Twenty-six patients developed thromboembolic complications. Apart from the fact that acute spinal cord injury patients are considered to be in an hypercoaguable state, the occurrence of deep vein thrombosis/pulmonary embolism (DVT/PE) in our study, even though these patients were on prophylactic low dose subcutaneous heparin, was related to delay in transfers, operative intervention, level of spinal cord injury and was possibly due to loss of some amount of heparin solution from the prefilled syringe during removal of air bubbles prior to the subcutaneous heparin injection.

Acute Disease↗
PubMed1992

Risk factors for abomasal volvulus and left abomasal displacement in cattle.

A hospital-based case-control study was conducted to evaluate and compare risk factors for abomasal volvulus (AV) and left displaced abomasum (LDA) in cattle. Medical record abstracts were derived from 17 North American veterinary schools by the Veterinary Medical Data Program for all cattle admitted between Jan 1, 1977 and Dec 31, 1986, and for those with a diagnosis of AV or LDA. From a total of 108,956 individual cattle records, 1,036 cases of AV and 7,695 cases of LDA were identified, with a ratio of LDA to AV cases of 7.4 to 1. In-hospital mortality was 23.5% for AV and 5.6% for LDA. Age, breed, gender, and season each had significant (P less than 0.05) effects on risk for AV and LDA. Risk for AV and LDA increased with increasing age, with greater risk in cattle aged 4 to 7 years. Dairy cattle were at higher risk of developing AV (adjusted odds ratio, 36.4) and LDA (adjusted odds ratio, 95.2) than were beef cattle. The odds of AV in Brown Swiss cattle were significantly (P less than 0.0001) lower, and the odds of LDA in Guernsey cattle were significantly (P less than 0.0001) higher than those in Holstein cattle. Female cattle were also at higher risk of developing AV (adjusted odds ratio, 3.3) and LDA (adjusted odds ratio, 29.1) than were male cattle. The odds of AV and LDA varied considerably throughout the year, with the lowest number of cases observed in autumn. Seasonal development of AV differed significantly (P less than 0.0001) from that of LDA, with the odds of AV and LDA being highest in January and March, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Abomasum↗