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Biomedical subjects

R W Redding

Publications and source records attributed to R W Redding.

At least 19 recordsLinked to original sources
PubMed1994

Sensory nerve conduction velocity of the dorsal penile nerves of bulls.

Mean conduction velocity of sensory axons of the dorsal penile nerves of clinically normal bulls was determined by recording action potentials evoked by cutaneous stimulation. Locations of stimulating and recording electrodes were standardized. Overall mean +/- SD conduction velocity was 55.1 +/- 5.1 m/s. Mean +/- SD velocity recorded from the distal electrode was 53.3 +/- 4.9 m/s; velocity recorded from the middle electrode was 55.3 +/- 5.0 m/s; and velocity recorded from the proximal electrode was 56.7 +/- 5.1 m/s. Differences among means were not significant. Four bulls had mean conduction velocities of 54.0 m/s and 48.4 m/s before and 3 weeks after castration, respectively.

Analysis of Variance↗
PubMed1987

Spinal-evoked potentials in dogs with acute compressive thoracolumbar spinal cord disease.

Spinal evoked potentials (SpEP) were recorded on an electromyograph from electrodes placed percutaneously in the ligamentum flava at the lumbosacral junction and between the 10th and 11th thoracic vertebrae following tibial nerve stimulation in 31 anesthetized dogs with acute compressive spinal cord injuries. The neurologic status of each dog was determined by clinical examination before SpEP recordings, and the neurologic status was monitored for 2 months in dogs that had surgical or conservative treatment. Two months after spinal injury, the response to treatment (outcome) of each dog was evaluated and graded as favorable (ambulatory and urinary continent) or unfavorable (nonambulatory, urinary incontinent, or euthanatized with confirmation of myelomalacia). Onset latencies, conduction velocities, amplitudes and durations of the wave forms, and the ratio of conduction velocity to combined durations of the first positive (P1) and first negative (N1) waves (CV/DPN index) were determined and were compared with reference data from clinically normal (control) dogs. Single SpEP recordings were of value in determining the prognosis for recovery. Significant differences were not found in the L7-S1 recordings between the reference (control) and spinal injury groups. Analysis of data from the T10-11 recordings indicated significant differences between the reference and spinal injury groups and between the favorable and unfavorable outcome groups within the spinal injury group. A CV/DPN index was less than 30 in dogs with unfavorable outcomes and greater than 30 in dogs with favorable outcomes. Stepwise discriminant analysis of data from the spinal injury group predicted outcome correctly in all dogs.

Animals↗
PubMed1986

Myotonia congenita in a Chow Chow pup.

Myotonia congenita was diagnosed in a 12-week-old female Chow Chow that had hindlimb ataxia, a stiff gait, and occasional collapsing. The diagnosis was based on the history, clinical signs, electrodiagnostics, and microscopic examination of biopsied muscle specimens.

Animals↗
PubMed1986

Abnormalities of the brainstem auditory response of the dog associated with equilibrium deficit and seizure.

The brainstem auditory evoked response (BAER) was recorded from 20 dogs, 10 exhibited vestibular deficit, and 10 presented with a history of seizures. Two dogs exhibited both types of signs. Abnormalities of the BAER, prolonged interwave latency, were seen in 8 of the 10 animals with vestibular problems, and in 7 of the 10 animals with seizure history. Several different diagnosis were associated with BAER abnormalities in both groups of animals. In 55.5% of the cases exhibiting abnormalities of the BAER, postmortem evidence of brainstem pathology was not detected. The electroencephalogram (EEG) was normal in three instances of abnormalities of the BAER. The BAER was normal in three dogs with abnormalities of the EEG. The BAER is presented as a useful diagnostic tool for brain lesions in animals with vestibular deficit and seizure history, but appears most useful when used in conjunction with the EEG. Correlations of abnormalities of the BAER and clinical course of disease are discussed.

Animals↗
PubMed1985

Reference values of the brainstem auditory evoked response of methoxyflurane anesthetized and unanesthetized dogs.

The brainstem auditory evoked response (BAER) was recorded from 7 unanesthetized and 27 methoxyflurane anesthetized dogs. A 0.1 msec, 70 dB stimulus delivered at 10 Hz evoked the expected seven wave BAER. Mean peak wave latencies and standard deviations were calculated. Differences were not found between neither right and left ears, nor male and female dogs. The anesthetized dogs had a significantly longer latency for all waves, except wave I, than the unanesthetized dogs. Use of the BAER as a diagnostic technique for brainstem lesions is recommended.

Anesthesia↗
PubMed1985

Electroencephalographic patterns of clinically normal, sedated, and tranquilized newborn foals and adult horses.

To establish a clinically practical procedure for recording the equine EEG, 25 healthy adult horses and 6 newborn foals were used. Recordings were taken with the animals alert and tranquilized, confined in metal stocks, or physically restrained. The dominant alert waveforms of adult horses were fast activity (25 to 40 Hz) with medium-to-low voltages (5 to 40 microV-dominant 10 to 15 microV). Underlying this fast activity was slower (0.5 to 4.0 Hz) activity with medium-to-low voltages (10 to 40 microV). Twelve of the 25 adult horses had EEG frequencies in the alpha frequency range (10 to 15 Hz, 10 to 50 microV). Eight horses were given xylazine and 17 were given acetylpromazine. Those given xylazine had generalized slowing with several distinct frequency patterns (25 to 40 Hz, 5 to 30 microV; 10 to 15 Hz, 10 to 80 microV; and 0.5 to 4.0 Hz, 10 to 90 microV). Horses given acetylpromazine had fast activity (25 to 40 Hz) with medium-to-low voltages (5 to 40 microV). Underlying this activity were slower waveforms (1 to 4 Hz) with medium-to-low voltages (5 to 10 microV). Occasional well-formed spindle activity was observed (10 to 14 Hz, 10 to 50 microV). Acetylpromazine had little effect on the EEG recording, whereas xylazine exerted a substantial effect. All leads were synchronous with lower voltages in the left frontal, right frontal, and transfrontal leads. The alert pattern of a newborn foal was characterized by low frequency (2 to 6 Hz) with medium-to-high voltages (20 to 90 microV).(ABSTRACT TRUNCATED AT 250 WORDS)

Acepromazine↗
PubMed1985

Effects of fentanyl citrate and droperidol on electroencephalographic findings in dogs.

Electroencephalograms were recorded from 10 dogs before, immediately after, and every 10 minutes (for 60 minutes) after IV injection of 0.005 ml of a fentanyl citrate and droperidol combination/kg of body weight. Narcosis was adequate for recording. At 30 to 40 minutes after injection, tail wagging was the only adverse reaction (EEG artifact) observed. The only changes in EEG activity observed were a slight increase in amplitude of the dominant activity and an increase in spindle-like activity. Daily repetition for 5 days did not alter the EEG pattern or the behavior of the dogs.

Animals↗
PubMed1985

Characteristics of F and H waves of ulnar and tibial nerves in cats: reference values.

The latencies and latency rates of H and F waves were determined by percutaneous stimulation of the ulnar and the tibial nerves of healthy cats. In the ulnar and tibial nerves, the latency rates of H wave evoked compound action potentials were 49.1 +/- 7.3 and 44.1 +/- 2.7 m/s, respectively, and of F waves were 68.1 +/- 9.6 and 57.1 +/- 6.2 m/s, respectively. The H wave response of cats was more variable in latency and amplitude than that reported in the dog.

Animals↗
PubMed1984

Spinal-evoked potentials and spinal conduction velocity of the cat: reference values.

Spinal conduction velocities of the fastest afferent fibers of the spinal cord were calculated from the onset latencies of averaged evoked responses elicited by stimulation of the tibial nerve sensory afferent fibers and were recorded at various sites on the spinal cord. Locations for stimulation and recording electrodes were identified. Waveforms, mean amplitudes, and duration of the evoked spinal potentials were described. The mean conduction velocity of the spinal cord afferents at T12-T13 was 74.25 m/s with a SD of +/- 9.81 m/s. The mean conduction velocity of the spinal cord afferents, determined at the cisterna magna, was 80.66 m/s with a SD of +/- 11.50 m/s. This is a slight increase over the spinal conduction velocity at T12-T13 (P = 0.05).

Animals↗
PubMed1984

Sensory nerve conduction velocity of cutaneous afferents of the radial, ulnar, peroneal, and tibial nerves of the cat: reference values.

The mean conduction velocities of the compound action potentials of sensory axons of the cutaneous branches of the radial, ulnar, peroneal, and tibial nerves of the healthy cat were determined by cutaneous stimulation and recorded by averaged evoked response technique. Locations for both stimulation and recording electrodes were identified. Mean conduction velocities were: radial nerve, 83.6 +/- SD 8.3; ulnar nerve, 89.2 +/- 10.3; peroneal nerve, 85.3 +/- 6.8; and tibial nerve, 80.2 +/- 7.9 m/s.

Afferent Pathways↗
PubMed1982

Sensory nerve conduction velocity of cutaneous afferents of the radial, ulnar, peroneal, and tibial nerves of the dog: reference values.

The mean conduction velocities of the compound action potentials of sensory axons of the cutaneous branches of the radial, ulnar, peroneal, and tibial nerves of the healthy dog were determined by cutaneous stimulation and recorded by averaged evoked response technique. Locations for both stimulation and recording electrodes were identified. Mean conduction velocities were: radial nerve = 65.1 +/- 6.2; ulnar nerve = 69.4 +/- 6.9; peroneal nerve = 64.4 +/- 5.25; and tibial nerve = 63.4 +/- 5.3 m/s +/- SD.

Action Potentials↗
PubMed1981

Effects of xylazine and ketamine hydrochloride on the electroencephalogram and the electrocardiogram in the horse.

A continuous series of electroencephalograms (EEG) was obtained from each of 6 mature horses which had been given xylazine and ketamine hydrochloride IV. Electrocardiograms and respiratory rates were also obtained. The EEG of the unsedated standing adult horse displayed a dominant fast activity in the range of 25-35 Hz, 5-30 microV superimposed over slower 1-4 Hz, 10-50 microV activity with occasional 10-14 Hz, 10-40 microV spindle-type activity. The xylazine-sedated horse displayed hypersynchronous EEG patterns, with the dominant activity being 1-3 Hz, 10-70 microV with overlying mixed frequencies of 5-10 Hz, 10-40 microV and 10-14 Hz, 10-40 microV spindle-type activity. Some 25-35 Hz, 5-10 microV activity was present in 5 of the 6 horses. Ketamine administration 3 minutes after xylazine injection caused an increase in high-voltage slow activity. The dominant frequency was 1-3 Hz, 20-100 microV, with superimposed mixed irregular frequencies of 6-10 Hz, 10-50 microV and 10-14 Hz, 10-40 microV spindle-type activity. All horses developed some degree of second-degree atrioventricular (AV) heart block approximately 23 s after xylazine was injected. The second-degree AV heart block disappeared approximately 1 minute and 30 s after ketamine was injected in 4 of the 6 horses. The remaining 2 had second-degree AV heart block throughout the recording period (15 to 18 minutes). Respiration rates were depressed after xylazine was given and became irregular and apneustic after ketamine injection. The cyclic rate of respiration varied from 19 to 30 breaths/minute. Xylazine depressed heart rates from 13% to 41% (mean 29.3%). Heart rates became faster or remained unchanged after ketamine was administered.

Animals↗
PubMed1980

Distal symmetrical polyneuropathy in a dog.

A 1.3-year-old Great Dane dog had a chronic progressive neurologic disease clinically expressed as a distal symmetrical polyneuropathy characterized by weakness and bilateral atrophy of bulbar and distal appendicular musculature. Qualitative and quantitative studies showed neurogenic atrophy of muscles below the elbow and stifle. There was Wallerian-type degeneration, Schwann cell proliferation and cell bands of Büngner, and marked depletion of medium (5 to 8 microns) to large (9 to 15 microns) diameter myelinated fibers in the distal parts of appendicular and laryngeal nerves. Sensory (saphenous and superficial radial) and autonomic (sympathetic and dorsal vagal trunk) nerves were affected to a lesser degree. A distribution of distal axonal degeneration suggested a dying back process. The disease differed from classical dying back disorders by absence of axonal degeneration in selected pathways of the central nervous system.

Animals↗
PubMed1980

Experimental hemorrhage in splenectomized and nonsplenectomized dogs.

Ten splenectomized and ten nonsplenectomized conscious dogs were subjected to hemorrhage of 41% of their blood volume over a 15-minute period. Hemodynamic and metabolic variables were monitored for 4 hours after hemorrhage. Mortality (100%) occurred in the splenectomized group. Significant (P < 0.001) hemodynamic responses after hemorrhage included hypotension, tachycardia, low central venous pressure, and decreased ECG voltage of the R wave. Tachypnea was noted in the absence of hypoxia, hypercapnia, and acidosis inthe nonsplenectomized dogs. Significant (P < 0.001) hypocapnia and mean PCO2 values of 13.9 MM of Hg and 23.5 mm of Hg in splenectomized and nonssplenectomized dogs, respectively, was noted. Mean hemoglobin levels were significantly (P < 0.001) decreased after hemorrhage in the splenectomized dogs. The absence of a change in hemoglobin in thenonsplenectomized dogs was attributed to the translocationof extracellular fluid into the vascular space which diluted the high concentration of RBC from splenic contraction. Other changes noted after hemorrhage were hyperglycemia, increased blood cortisol, and increased pyruvate and lacte levels. Changes were not noted in pyruvate-to-lactate ratios.

Animals↗
PubMed1980

Maturation of nerve conduction velocity and the evoked muscle potential in the dog.

Maximum nerve conduction velocity (NCV) of motor fibers in the ulnar nerve was measured in dogs ranging in age from 12 hours after birth to 32 weeks and older. The evoked muscle potential (EMP) resulting from ulnar nerve stimulation was recorded from an interosseous muscle and measured for latency, duration, and amplitude. There was a sharp increase in NCV from 6.3 +/- 0.28 m/s (mean +/- SEM) in dogs from 12 hours to 1 week of age to 59.04 +/- 1.41 m/s in dogs 32 weeks and older. The latency of the EMP, resulting from stimulating the ulnar at either a proximal or a distal site, decreased markedly after birth to 4 to 5 weeks and then more gradually until 10 to 12 weeks. In dogs between 10 to 12 weeks and 32 weeks and older, latency increased but was never as high as in the newborn. Duration of the EMP followed a similar pattern. Amplitude increased sharply with age, resulting in a final 14- to 18-fold increase by 32 weeks and older.

Animals↗
PubMed1979

Idiopathic facial paralysis in the dog.

Facial nerve paralysis of acute onset is reported in seven mature dogs, five of which were cocker spaniels. The clinical signs were characterised by ear drooping, lip commissural paralysis, sialosis, and collection of food on the paralysed side of the mouth. All dogs showed absent menace responses and trigeminofacial/acousticofacial reflexes. Horner's syndrome was not present in any dog. In four dogs, bilateral facial paralysis developed. The facial paralysis was unrelated to otitis media. Electrodiagnostic studies revealed denervation potentials and absent evoked muscle potentials. Facial nerve biopsies from two cases showed nerve fibre degeneration and apparent loss of larger diameter myelinated fibres. The condition has been termed idiopathic facial paralysis since the aetiopathogenesis is presently unknown.

Animals↗