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Biomedical subjects

L L Blythe

Publications and source records attributed to L L Blythe.

At least 37 records · Page 2Linked to original sources
PubMed1991

Evaluation of the oral vitamin E absorption test in horses.

An oral vitamin E absorption test used in human beings was modified for use in horses. The most appropriate techniques with which to measure gastrointestinal tract absorption of vitamin E (alpha-tocopherol) in horses were developed. Vitamin E was administered orally, and serum values of alpha-tocopherol were measured by use of high-performance liquid chromatography at 0, 3, 6, 9, 12, and 24 hours after vitamin E administration. Variables included comparison of 2 dosages (45 and 90 IU/kg of body weight), routes of administration, and absorption dynamics of 3 preparations of dl-alpha-tocopherol. Absorption of the 2 doses of dl-alpha-tocopherol acetate indicated a dose response; the area under the curve at 24 hours (AUC24) was 4.3 micrograms.h/ml for the 45-IU/kg dose and 32.2 micrograms.h/ml (P less than 0.01) for the 90-IU/kg dose. Maximal absorption was apparent when vitamin E was naturally consumed in grain, compared with administration of identical preparations by stomach tube or paste. In the same horses, dl-alpha-tocopherol and dl-alpha-tocopherol acetate plus polyethylene glycol had statistically similar absorption curves and both had significantly greater AUC24, compared with dl-alpha-tocopherol acetate; values for the 3 compounds were 23.6, 25.8, and 12.6 micrograms.h/ml, respectively. The AUC24 varied between individual horses, but time of peak value was consistently observed between 6 and 9 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1990

Myelitis in a cat infected with Toxoplasma gondii and feline immunodeficiency virus.

Severe necrotizing myelitis secondary to localization and reactivation of Toxoplasma gondii within the spinal cord of a domestic shorthair cat was diagnosed by use of light and electron microscopy and immunohistochemistry. The cat also was infected with feline immunodeficiency virus. This case may have useful comparative features to T gondii infections in human patients with acquired immunodeficiency syndrome.

Animals↗
PubMed1989

Variations of serum vitamin E, cholesterol, and total serum lipid concentrations in horses during a 72-hour period.

Fluctuations of serum vitamin E (alpha-tocopherol), cholesterol, and total lipids were monitored in 12 horses at 3-hour intervals for 72 hours. Mean coefficients of variation were 12, 5, and 15%, respectively. Statistical analyses were used to conclude that instrumentation error was accountable for only a small portion of the vitamin E variation. Results indicated that a single serum sample assay is an unsatisfactory indicator of vitamin E status in horses. These data have clinical application in the evaluation of horses suspected to be affected with equine degenerative myeloencephalopathy. The large variance of serum total lipids and the lack of correlation of it with serum vitamin E over time preclude the use of vitamin E/serum total lipids ratio in assessing vitamin E status.

Animals↗
PubMed1988

Comparison of sensory nerve conduction velocities in horses versus ponies.

Normal sensory nerve conduction velocity (SNCV) values in 8 ponies and 8 horses were compared by use of a percutaneous signal-averaging technique. Nerve fibers evaluated included those in the medial and lateral palmar and plantar digital nerves. Mean SNCV values were significantly slower (P less than 0.0002) for horses, compared with those values for ponies. Animal height and nerve segment length were inversely related to SNCV consistently. The SNCV values were affected by surface skin temperature by a factor of approximately 1.2 m/s change for 1 degree C change in temperatures from 35 C. The ability to calculate warning limits to define those SNCV values in normal and abnormal ranges were developed from these data for both ponies and horses.

Animals↗
PubMed1987

Neurologic examination of the horse.

Methodology for the neurologic examination in the equine species is described. Information is organized to assist the reader in defining neurologic deficits and in localizing lesions to the major subdivisions within the central or peripheral nervous system. Numerous examples of deficits are presented to assist the reader in recognition of common neurologic disease states.

Animals↗
PubMed1987

Evaluation of the potential for interference by dimethyl sulfoxide (DMSO) in drug detection in racing animals.

Dimethyl sulfoxide (DMSO) had been postulated to be a 'masking agent' when used concurrently with therapeutic or prohibited drugs in racing animals. Eight drugs (flunixin, furosemide, caffeine, apomorphine, phenylbutazone, lidocaine, cocaine, and acepromazine maleate) were administered to six horses singly and with concurrent intravenous DMSO. Urine samples were analyzed for the presence of the drugs and/or their metabolites by thin layer chromatography. Direct comparison of thin layer chromatograms of extracts of positive urine samples with and without DMSO verified that DMSO did not interfere with the detection of these drugs.

Acepromazine↗
PubMed1986

Factors affecting prerace dehydration and performance of racing greyhounds.

Several factors, including age, sex, race number, post position, and race class, were evaluated for relationships to prerace percentage body weight loss and performance in all Greyhounds racing during August 1983 in Oregon. The incidence of percentage body weight loss greater than or equal to 2.5% was low (5%). Race number had a direct effect on weight loss; the later the dogs raced, the more weight loss they experienced. Female dogs were 3 times more likely to lose greater than 2.4% of body weight than males. All dogs experiencing greater than 2.4% body weight loss were 2 times more likely to finish in the first 3 places when racing in the first 5 races overall. In addition, males losing greater than 2.4% of body weight performed better than females when racing together in the final 6 races. Males appeared to be better performers than females, as they were twice as likely to be in class A races. However, once in the race, males and females performed equally.

Age Factors↗
PubMed1986

Effects of racing on hematologic and serum biochemical values in greyhounds.

Blood samples were collected on nonracing days from 57 racing Greyhounds at 2 weeks, 8 weeks, 13 weeks, and 16 weeks after the beginning of the racing season. Hematologic and biochemical tests were performed to detect marked changes induced by stress of racing. In general, these Greyhounds were healthy. Rhabdomyolysis was detected in one dog. In several other dogs, possible subclinical muscle injury was identified by increased serum creatine kinase activities. Mean serum Ca concentrations tended to decrease during the racing season. None of the tests was a good predictor of racing performance. Mean values for several hematologic and biochemical tests were different from those of other breeds of dogs.

Animals↗
PubMed1986

A chronic in vivo liver perfusion technique in ruminants.

A model for chronic perfusion of the liver of ruminants was developed. This allowed for investigation of the pathophysiology of pyrrolizidine alkaloids (PA) in two species. This model has general application to toxicological studies for both acute or chronic perfusion, as well as, metabolic studies utilizing sheep, cattle or goats. Catheterization of the portal vein via the right ruminal vein was done to separate the ruminal effects of toxin metabolism and absorption from the direct effects of PA on liver tissue. The selection of this vessel insured the equal distribution of infused substances throughout all lobes of the liver. A left flank laparotomy surgical approach was used. A dacron patch glued to the catheter at vein entry site eliminated a number of common catheter problems. Catheters were used for infusion of up to 2 L/daily for 20 d to 7 mo.

Animals↗
PubMed1986

Pharmacokinetic disposition of dimethyl sulfoxide administered intravenously to horses.

Dimethyl sulfoxide (DMSO) was administered IV to 6 Thoroughbred horses at 2 dosages: 1.0 g/kg and 0.1 g/kg. The pharmacokinetics seemed linear, with biological half-lives of 8.6 +/- 0.3 hours and 9.8 +/- 2.2 hours for the 1.0 g/kg and 0.1 g/kg dosages, respectively. This was further substantiated by mean residence times of 9.8 +/- 0.44 hours and 13.8 +/- 4.25 hours, areas under the curve of 12.55 +/- 1.42 mg/ml/hr and 1.63 +/- 0.49 mg/ml/hr, and the clearances of 0.081 +/- 0.009 L/kg/hr and 0.066 +/- 0.022 L/kg/hr for the large and small dosages, respectively. At 12 hours after 1.0 g/kg was administered, 26.6% of the DMSO dose was excreted unchanged into the urine; at 12 hours after 0.1 g/kg was administered, 25.3% of the DMSO dose was excreted unchanged into the urine. It was predicted that 29.4% and 40.6% of the total DMSO dose would be excreted into the urine for the 1.0 g/kg and 0.1 g/kg dosages, respectively. A 10% DMSO concentration in normal saline solution was safe to give as rapid IV infusion. Slow administration is recommended for more concentrated solutions. Based on the half-life, DMSO should be administered 2 times a day IV for the treatment of increased intracranial pressure and/or cerebral edema in horses.

Animals↗
PubMed1985

Effects of oral cimetidine on plasma concentrations of phenylbutazone in horses.

Phenylbutazone was administered to six Thoroughbred horses in a cross-over study in which the horses received cimetidine pretreatment or no cimetidine pretreatment. Blood samples were collected at various times for 48 h after phenylbutazone administration and the plasma was analysed for phenylbutazone. Cimetidine pretreatment elevated phenylbutazone plasma concentrations during the first 8 h after phenylbutazone administration. The absorption rate, maximum phenylbutazone plasma concentrations and AUC were significantly greater with cimetidine pretreatment. The half-life of phenylbutazone did not change with cimetidine pretreatment; however, lower plasma concentrations of the metabolite gamma-hydroxyphenylbutazone were observed with cimetidine pretreatments. Plasma concentrations of the metabolite oxyphenbutazone were unchanged with cimetidine pretreatment compared to control values. Twenty-four-hour plasma concentrations of phenylbutazone were not different from control values with cimetidine pretreatment. This study suggests that concurrent treatment with cimetidine and phenylbutazone 24 h before race time does not result in elevations of plasma phenylbutazone concentrations above control values.

Administration, Oral↗
PubMed1984

Vestibular syndrome associated with temporohyoid joint fusion and temporal bone fracture in three horses.

Acute onset of vestibulocochlear and facial nerve dysfunction due to a stress fracture of the petrous part of the temporal bone was diagnosed in 3 horses. The fracture was secondary to chronic inflammatory changes in the petrous part of the temporal bone and the proximal stylohyoid bone, with fusion of the temporohyoid joint. Bacterial meningoencephalitis was a complicating factor. Treatment resulted in reduction of severity of clinical signs in 2 of the 3 cases, but residual compensated vestibular deficits persisted.

Animals↗
PubMed1983

Chronic encephalomyelitis caused by canine distemper virus in a Bengal tiger.

A chronic progressive neurologic disease was observed and monitored for 18 months in a young, tamed Bengal tiger. Clinical, serologic, and neuropathologic evidence of canine distemper virus infection was seen. Clinical signs included convulsions, myoclonus, and slowly progressive ataxia. Marked increases in neutralizing antibodies against canine distemper virus were seen in the serum and cerebrospinal fluid. Neuropathologic findings were nonsuppurative meningoencephalomyelitis, with perivascular cuffing, demyelination, and inclusion bodies typical of canine distemper virus. It was concluded that, in light of this case and an earlier report of canine distemper in lion cubs, vaccination of this subgroup of carnivores with a killed vaccine may be beneficial if exposure to other animals susceptible to canine distemper is anticipated.

Animals↗
PubMed1983

Palatal myositis in horses with dorsal displacement of the soft palate.

The histologic and histochemical features of palatine muscles from 53 horses were studied; 25 of the horses were racehorses that had upper airway obstruction associated with dorsal displacement of the soft palate and 28 of the horses did not have any respiratory disorders and served as controls. Pathologic features observed included myonecrosis, phagocytosis, mononuclear cell infiltration of perimysial connective tissue, alkaline phosphatase-positive myofibers, and myofibers with cytoarchitectural changes that included irregular staining of the intermyofibrillar sarcoplasm and sarcoplasmic masses. These histopathologic features were judged to be indicative of myositis. Those features were found in both control horses and horses with dorsal displacement of the soft palate; however, their prevalence was higher in horses with dorsal displacement of the soft palate. For the control horses as well as the horses with dorsal displacement of the soft palate, the inflammatory changes were more prevalent in older horses. The finding of myositis suggests that palatal muscle weakness may contribute to the development of dorsal displacement of the soft palate; however, the myositis might have been secondary to trauma associated with displacement of the soft palate. We could not distinguish between these 2 possibilities. A large number of horses with dorsal displacement of the soft palate also had concurrent pharyngeal lymphoid hyperplasia. Extension of the mucosal inflammatory changes associated with pharyngeal lymphoid hyperplasia into the underlying palatine muscle might have accounted for the myositis.

Airway Obstruction↗
PubMed1983

Sensory nerve conduction velocities in forelimb of ponies.

Normal nerve conduction velocity values in 10 ponies were determined for sensory nerve fibers in the median and ulnar nerves. A percutaneous signal-averaging technique was developed and used. Medial and lateral palmar digital nerves on the abaxial surface of the proximal sesamoid bones were used as the sites for percutaneous stimulation, whereas recording sites included the medial and lateral palmar nerves just distal to the carpus and the median and ulnar nerves in the middle of the radius. Sensory nerve conduction velocities can be evaluated simply and clinically in the limbs of horses, using percutaneous signal-averaging techniques.

Action Potentials↗
PubMed1982

Electrophysiologic studies of the thoracic limb of the horse.

The cutaneous innervation of the thoracic limb was investigated in 18 barbiturate-anesthetized horses, using electrophysiologic techniques. The cutaneous area (CA) innervated by each cutaneous nerve was delineated in at least 4 horses by stroking the hairs with a small watercolor brush while recording from the nerve. Mapping of adjacent CA revealed areas of considerable overlap. The part of a CA of a given nerve supplied only by that nerve is referred to as its autonomous zone (AZ). In contrast to the standard textbook illustrations cutaneous branches of the axillary, radial, musculocutaneous, and ulnar nerves overlapped extensively in the antebrachium. Clinically testable AZ were found in the antebrachium for the caudal cutaneous antebrachial nerve of the ulnar nerve and in the carpus and manus for the cutaneous branches of the median, ulnar, and musculocutaneous nerves; AZ were not found for the cutaneous branches of the radial and axillary nerves.

Animals↗
PubMed1980

A light and electron microscopic study of sarcocysts in a horse.

The structure of sarcocysts in a horse is presented. Light microscopic examination revealed that the maximum cyst dimensions were 136 X 990 micrometers and the cyst walls were striated and 1 to 3 micrometers thick. Electron microscopic examination revealed that the "cyst wall" was formed by villuslike protrusions of the parasitophorous vacuole's primary wall. A unique feature was the presence and arrangement of microtubules within the parasitophorous vacuole. Thirty-four to 55 microtubules extended from the apical tips and sides of each villus and passed through the ground matrix to form junctions with the outer pellicle membrane of bradyzoites and metrocytes located at the margins of the cyst. The average dimensions of the bradyzoites were 3.2 X 14.2 micrometers.

Animals↗