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Biomedical subjects

P R Stephens

Publications and source records attributed to P R Stephens.

8 recordsLinked to original sources
PubMed1994

Murine experimental infection with rotavirus SA-11: clinical and immunohistological characteristics.

Six- to eight-day old (lactent) mice were inoculated orally with simian SA-11 rotavirus. During the first hours after infection, the virus was already detected in villous apical enterocytes by immunohistologic reaction of paraffin sections of the duodenum and jejunum but not in the ileum. Late on the first day, some animals developed already diarrhoea and pathologic lesions were observed in the duodenum and jejunum. During the second day most mice developed diarrhoea; tissue lesions were intense and maximal from duodenum to ileum when compared to other days and some colon sections had mild pathological characteristics. At this point, the virus in the ileum was only detected by immunohistologic reaction. During the third day some animals still had diarrhoea but tissue histology was regenerated and no virus could be detected. We conclude that the SA-11 model follows an infection pattern similar to Epizootic Diarrhoea of Infant Mice (EDIM) and propose to study immunological parameters as young susceptible animals mature into adult resistant ones.

Animals↗
PubMed1990

Erysipelothrix rhusiopathiae-induced septic arthritis in a calf.

A 14-week-old Holstein heifer with a 48-hour history of left tarsocrural joint effusion was referred for evaluation when lameness developed 24 hours after needle aspiration was attempted at the farm. Results of synovial fluid analysis were compatible with diagnosis of septic arthritis, and bacteriologic culture of the fluid yielded Erysipelothrix rhusiopathiae. The calf responded to tarsocrural joint lavage and penicillin G administration.

Animals↗
PubMed1989

Application of a Hall-effect transducer for measurement of tendon strains in horses.

Custom-designed Hall-effect strain sensors (HES) were implanted surgically onto the superficial digital flexor tendons of the forelimbs of 4 adult Thoroughbreds. Strains were recorded at various gaits, using a portable amplifer and FM cassette recorder. Strain calculations used the original length (L) as the HES position with the forelimb in the relaxed neutral position during anesthesia. A characteristic deflection in the strain cycle recording was confirmed to correspond to initial hoof contact with the ground (heel strike) by simultaneous recording of weight bearing via a footswitch. Heel strike was used as the reference point to determine the magnitude of strain change during weight bearing and nonweight bearing under various conditions. The weight-bearing strains (heel strike to maximal strain) recorded in 2 horses (with a rider) were 3.1% and 7.6% at the walk, 6.5% and 10.1% at the trot, and 11.5% and 16.6% at the gallop. Strain rate during tendon loading at the gallop was approximately 200%/s. The magnitude of strain change during nonweight bearing (minimal strain to heel strike) was smaller than during weight bearing, but also increased with faster gaits. In 3 horses led at the walk and trot, modest increases in hoof angle (baseline 52 degrees) resulted in small increases in the magnitude of strain change during weight bearing at the trot, but the magnitude of strain change at the walk was not affected. Results of the study indicated that the HES can be successfully adapted to provide continuous strain measurement without subjective signs of discomfort or lameness in horses during or after instrumentation.

Animals↗
PubMed1988

Slab fractures of the third carpal bone in standardbreds and thoroughbreds: 155 cases (1977-1984).

Case records and radiographs of 155 horses with third carpal bone (C3) slab fractures were reviewed. Of these cases, race records were obtained for 72 Thoroughbreds and 61 Standardbreds. Three performance criteria were examined: ability to make 1 start, ability to make 10 starts or earn $2,000 (within 1 year of first start after the fracture), and earnings per start. Treatment distribution (lag screw fixation, fragment excision, or rest) was similar in both breeds. Significant differences between breeds were identified in age and sex distributions, fracture displacement, and postinjury performance. In Thoroughbreds, there was a tendency for fractures to occur in the right C3 (59%); in Standardbreds, forelimbs were affected equally. The dorsomedial aspect of C3 was the site of fracture in 87% (135/155) of the cases. Horses referred for treatment were predominantly 2-year-old Standardbreds and 3-year-old Thoroughbreds. Females of both breeds were less likely to race after injury than males (46 vs 90%). In Standardbreds, all 38 horses with racing starts before fracture were able to race again. Prior racing starts were not related to outcome in Thoroughbreds. The effects of treatment on outcome were not significantly different. Fracture characteristics did not significantly affect outcome, but did influence treatment selection. Convalescent time was not correlated with any of the variables examined (including treatment) or related to outcome; time from admission to first start averaged 11 months. In STandardbreds, 77% of the horses with C3 slab fracture raced after injury; in Thoroughbreds, 65% raced. Earnings per start declined in each breed, but the decline was more pronounced in Thoroughbreds.

Analysis of Variance↗
PubMed1988

Small colon intussusception in a broodmare.

A 9-year-old pregnant Standardbred broodmare was evaluated for signs of mild abdominal pain, failure to defecate, and mild abdominal distention. Rectal examination revealed the leading edge of a small colon intussusception, and peritoneal fluid analysis indicated suppurative peritonitis. Surgical management, including reduction of the intussusception and small colon resection with end-to-end anastomosis, resulted in successful outcome (1-year follow-up evaluation). Postoperative complications including dehiscence of the ventral midline surgical incision and simple obstruction at the anastomosis site necessitated a second surgical procedure. Small colon intussusception is an uncommon cause of signs of abdominal pain and is similar to type-IV rectal prolapse.

Animals↗
PubMedDate not supplied

Osteochondral fragments within the dorsal pouch or dorsal joint capsule of the proximal intertarsal joint of the horse.

The anatomy of the dorsal pouch of the proximal intertarsal joint (PIJ) and its communication with the tarsocrural joint (TCJ) was studied in 15 pairs of hocks from young and mature horses. The mediolateral length of the TCJ-PIJ fenestration was 14 to 29 mm. The potential volume of the dorsal pouch of the PIJ was 3 to 5 ml, and a recess extended 10 to 28 mm medial to the medial commissure of the TCJ-PIJ fenestration. In a correlated clinical study, osteochondral fragments were identified radiographically within the dorsal pouch (category 1) or dorsal joint capsule (category 2) of the PIJ in 17 horses undergoing arthroscopic surgery of the TCJ. In six horses with category 1 lesions, osteochondral fragments were found free within the dorsal pouch and were removed. In five horses, category 1 fragments were not located. All 11 horses were reported by owners to be sound after surgery. In seven horses, a minimally displaced fragment was identified at the distal aspect of the medial trochlear ridge, within the insertion of the synovium separating TCJ and PIJ (one horse had both types of lesions in the same hock). Five of the seven category 2 fragments were removed at surgery. Of the seven horses with category 2 lesions, four were training or racing, two were unsound, and one was still convalescing at the time of follow-up.

Animals↗