Biomedical subjects

E C Firth

Publications and source records attributed to E C Firth.

At least 73 records · Page 4Linked to original sources

PubMed1993

Vascular characteristics of the cartilage and subchondral bone of the distal radial epiphysis of the young foal.

The vascular features of the distal epiphysis of the radius of 27 foals aged from 3 weeks premature to 120 days postpartum were determined. The limbs were perfused with barium, and the distal radius was sawn into sagittal slabs which were decalcified, cut into thin slices and radiographed. More arteries approached areas of thick cartilage than thin cartilage. In thick cartilage, vessels in a lattice network were observed, and adjacent to these vessels was sinusoidal filling in the epiphyseal subchondral bone, which had a similar pattern to sinusoidal filling in the metaphysis. The sinusoidal filling adjacent to thick cartilage was at the predisposition site for epiphyseal osteomyelitis lesions in foals. This particular type of bone infection occurs commonly in the foal, but much less commonly in other species. The vascular features of the immature epiphysis may account for the predominance of epiphyseal osteomyelitis in the foal.

Journal Article↗

PubMed1993

Kanamycin concentrations in synovial fluid after intramuscular administration in the horse.

Six adult ponies were injected in the same intramuscular site with kanamycin sulphate (10 mg/kg). Two hours later, arthrocenteses of the right metacarpophalangeal, radio-carpal, intercarpal, tibio-tarsal and metatarsophalangeal joints were performed within 3 minutes. Arthrocenteses of the same joints on the left side were conducted 5 hours later. When expressed as a percentage of plasma drug concentration, differences in synovial fluid drug concentration between the joints sampled at 2 and 5 hours after injection were not detected.

Animals↗

PubMed1993

Rhodococcus equi-associated osteomyelitis in foals.

Two cases of Rhodococcus equi infection in foals are described, in which osteomyelitis was a feature. Because rhodococcal infection is usually low grade and chronic, and because the signs of early metaphysitis can be subtle, any articular or periarticular swelling in a foal from a farm with a history of rhodococcosis should be strongly suspected to be associated with R equi until proven otherwise.

Actinomycetales Infections↗

PubMed1990

[Morphology of the immature radius and metacarpus in horses and the relationship to bone infection and osteochondrosis].

In chondro-osseous disease in the foal there are three main categories of lesions: (i) synovitis alone (type S), (ii) synovitis accompanied by osteomyelitis originating in the epiphysis of the juxta-articular bone (type E) and (iii) synovitis accompanied by osteomyelitis originating directly adjacent to the physis of the juxta-articular bone (type P). Observations made in studies of the immature radius and metacarpus provide an explanation for the apparent predisposition of some joints for this disease. Relevant clinical and therapeutical aspects are discussed.

Animals↗

PubMed1990

Diagnosis of metaphysitis in foals.

Acute metaphysitis was induced in the third metacarpal bone of five foals by injecting lipopolysaccharide intraosseously adjacent to the growth plate, and synovial fluid was collected from the metacarpophalangeal joint 6 hours later. A control injection of an equal volume of physiological saline was given in a similar site in the opposite limb. Mild transient lameness, fever, depression and anorexia occurred after the lipopolysaccharide injection. On the lipopolysaccharide-injected side there was an increased leucocyte count in the synovial fluid, with neutrophil predominance; this did not occur on the control side. From this study in foals we conclude that in cases of suspected bacterial metaphysitis, arthrocentesis of the joint adjacent to the metaphysitis should be conducted immediately.

Journal Article↗

PubMed1990

The effect of phenylbutazone on the plasma disposition of penicillin G in the horse.

A pilot study in two ponies showed that the plasma concentrations of intramuscularly administered procaine penicillin were higher if phenylbutazone was administered concurrently. In two other trials, each involving five horses, intravenous sodium penicillin was administered with and without concurrent intravenously injected phenylbutazone, and procaine penicillin was injected intramuscularly with and without oral phenylbutazone. In both cases the plasma concentrations of penicillin were higher when phenylbutazone was given. The pharmacokinetic parameters indicated that the effect was probably due to a lower peripheral distribution because the penetration of penicillin into the tissues was greatly reduced.

Administration, Oral↗

PubMed1990

Intra-osseous pressure and pressure pulse gradients along the equine third metatarsal bone.

Intra-osseous pressure measurements in the third metatarsal bone of anesthetised young and mature ponies demonstrated that a pressure gradient exists along the bone, the pressure being highest at the level of the nutrient foramen and decreasing distally and proximally from this point. The height of the intra-osseous pressure pulse also decreased toward the bone ends. It is concluded that the sites of measurement of the intra-osseous pressure in clinical and experimental studies should be standardized.

Animals↗

PubMed1989

Intra-abdominal versus intramuscular application of two ampicillin preparations in cows.

Plasma ampicillin concentrations were determined in a cross-over trial involving five cows after single intramuscular or intra-abdominal administration of sodium ampicillin (10 mg/kg) and ampicillin anhydrate (40 mg/kg). After injection of sodium-ampicillin, high plasma concentrations were reached within 10 min; Cmax following intramuscular injection was 9.1 micrograms/ml and after intra-abdominal injection 7.5 micrograms/ml. Urine concentrations of ampicillin were low after 24 h (1-1.5 micrograms/ml). No significant changes in blood leucocyte numbers, plasma zinc, iron or fibrinogen levels occurred. After injection of ampicillin anhydrate 1 h elapsed before maximum plasma levels were obtained; Cmax was 5.4 micrograms/ml after intramuscular and 6.7 micrograms/ml after intra-abdominal administration. Urine concentrations were very high (238-303 micrograms/ml) after 24 h and stayed above 1 microgram/ml for 6 days. After administration of ampicillin anhydrate a significant increase in blood neutrophils (P less than 0.01) and a significant increase in plasma fibrinogen was measured after intramuscular and intra-abdominal injection (P less than 0.05). A significant decrease in plasma zinc concentration after intra-abdominal injection occurred (P less than 0.05). In abdominal surgery in cows in which contamination cannot be prevented, and practical objections inhibit preoperative administration, intramuscular or intra-abdominal administration during surgery of sodium ampicillin seems justified. Ampicillin anhydrate should not be used intra-abdominally.

Ampicillin↗

PubMed1988

Infection rates in contaminated surgical procedures: a comparison of prophylactic treatment for one day or four days.

Eighty-three calves with a complicated umbilical hernia were included in a randomised prospective study. The frequency of wound infection was compared in two groups. The first group received antibiotics for one day, the second group for four days. The infection rate in calves receiving antibiotics for one day was 25 per cent compared with 8 per cent in calves treated for four days (P less than 0.05). Male calves were more susceptible to infection than female calves.

Ampicillin↗

PubMed1988

Infection rates in clean surgical procedures with and without prophylactic antibiotics.

One hundred calves with an uncomplicated umbilical hernia were included in a prospective study. The frequency of wound infection and recurrence of herniation were compared in animals operated on either with or without prophylactic antibiotics. In 90 calves operated on for the first time (60 without antibiotics and 30 with antibiotics) there were no infections and only one hernia recurred. In 10 calves operated on for the second time (seven without antibiotics and three with antibiotics) there were two infections and one hernia recurred in the group not receiving antibiotics.

Animals↗

PubMed1988

Results of operative treatment of equine colic with special reference to surgery of the ileum.

This retrospective study presents the results of surgical treatment of obstructive colic in horses operated in the last decade (1976-1985). The overall short-term recovery rate (i.e. discharged from hospital) was 51% of cases presented for surgery, and 68% of cases which were considered to be amenable to surgical therapy. For long-term results (6 months-8 years follow up) these percentages must be reduced by about 15% due to mortality after discharge. Special attention has been given to surgery of the ileum, which is often involved in strangulation or obturation, and accounts for about 26% of gastrointestinal surgical disorders. The long-term recovery rate of ileal surgery was 54.3%, but ileocaecal intussusception and jejunocaecostomy with resection have a much poorer prognosis. The results of this study indicate that resection of the ileum should be avoided unless necrosis is present or threatening. The alternative is creation of a shunt between (distal) jejunum and caecum, thus bypassing the ileum and ileocaecal junction and preserving the original anatomical relationships.

Animals↗

PubMed1988

The site of focal osteomyelitis lesions in foals.

The long bone ends of foals with infectious disease were sawn into sagittal slabs, washed and inspected. Tissue suspected to be abnormal on the basis of change of colour and consistency was radiographed, and then decalcified and examined histologically. The exact site of 140 focal osteomyelitis lesions from 18 foals was determined. There were more lesions in the epiphysis than the metaphysis. Epiphyseal lesions were in specific sites within a given epiphysis, and in most epiphyses the lesions were at the site of thickest cartilage. Metaphyseal lesions in the metacarpal, metatarsal and distal radial growth plates tended to be on the more inclined parts of the growth plate.

Animals↗

PubMed1988

Effect of induced synovial inflammation on pharmacokinetics and synovial concentration of sodium ampicillin and kanamycin sulfate after systemic administration in ponies.

Single doses of sodium ampicillin (10 mg/kg) and kanamycin sulfate (5 mg/kg) were administered intramuscularly (i.m.) separately, and then together, to five pony mares. The plasma antibiotic concentration-time curves were constructed. The pharmacokinetic parameters of the antibiotics given separately were not altered by concurrent administration. Four of the five pony mares were then given the i.m. kanamycin/ampicillin combination 4 h after acute synovitis and fever had been induced by injection of lipopolysaccharide into the left intercarpal joint. The plasma concentration-time curves and the synovial concentration-time curves of inflamed and normal joints were constructed. The Cmax of ampicillin in the lipopolysaccharide experiment was significantly higher than in the other experiments. The antibiotics entered the synovial fluid of the inflamed joints more quickly and attained higher concentrations than in the uninflamed joints. The ampicillin concentration exceeded 5 micrograms/ml in inflamed synovial fluid for some 2.5 h after injection, and kanamycin sulfate concentration exceeded 2 micrograms/ml for 7 h.

Ampicillin↗

PubMed1988

Measurements of bone strain in foals with altered foot balance.

Two to 7 days after birth, 9 foals were anesthetized, and strain gauges were applied to lateral and medial aspects of the third metacarpal bone of the left forelimb. In 5 of these foals, strain gauges also were applied to the radius of the left forelimb. Four to 6 days later, foals were walked (5 sets of 10 to 20 strides), and compressive and tensile strains in the bone beneath strain gauges were recorded on paper and diskette. After recording base-line data, a wedge was fitted to the hoof of the limb with the strain gauges, in such a way that the lateral bearing surface was raised, and strains were recorded again. The wedge was left in place, and further recordings were made every 2 to 3 days for 10 days. At the normal walk (base-line data), the compressive strain was higher than the tensile strain in the third metacarpal bone, on the medial side of which the mean principal compressive strain was approximately twice that on the lateral surface. Immediately after application of the wedge, strain values from the medial surface of the third metacarpal bone decreased by 40%, and the lateral surface compressive strain increased by 100%. These changes gradually decreased over 10 days, at which time there was no significant difference from base-line values (P less than 0.05). Similar but much less obvious trends were observed in the radius. Abnormal hoof balance apparently had no lasting effect on compressive forces running through the limb, and the natural situation of higher compressive strain medially was restored quickly.

Animals↗

PubMed1988

Intra-osseous pressure of the equine third metatarsal bone.

Intra-osseous pressure was measured in the third metatarsal bone of 8 pony foals at the age of 1, 3, 6 and 26 weeks of age, and on one occasion in the third metatarsal bone of 5 ponies aged 1-5 years; the animals were under general anesthesia and in lateral recumbency. Saphenous venous pressure and lateral superficial plantar metatarsal arterial pressure were also monitored throughout the procedure. There were no statistically significant changes in the epiphyseal, diaphyseal, venous or arterial pressures with increasing age of the foals. There was no statistically significant difference between the mean epiphyseal and mean diaphyseal pressures in the foals. Individually however, the diaphyseal pressure exceeded the epiphyseal pressure in 32 of the 36 measurements made in the foals. Saphenous vein occlusion and intravenous adrenalin administration showed that both venous and arterial pressures influence intra-osseous pressure. Intra-osseous injection of heparinized saline on one side of the growth plate produced an immediate massive increase in intra-osseous pressure on that side of the growth plate, but in almost all cases a concomitant rise in intraosseous pressure on the other side of the physis did not occur. Simulated effusion of the metatarsophalangeal joint was associated with an increase in intraosseous pressure in the adjacent metatarsal epiphysis, and flexion of the joint with an increase in intraosseous pressure in both the epiphysis and the metaphysis.

Aging↗

PubMed1987

Haematogenous osteomyelitis in cattle.

The examination of 70 cattle with haematogenous osteomyelitis resulted in the classification of the bone lesions into two main groups: the physeal type, in which an infection, usually of metaphyseal bone, originated at or near the growth plate, usually in the distal metacarpus, metatarsus, radius or tibia, and the epiphyseal type, in which an infection originated near the junction of the subchondral bone and the immature epiphyseal joint cartilage, most often in the distal femoral condyle epiphysis, the patella and the distal radius. Combinations of physeal and epiphyseal defects and even diaphyseal involvement were occasionally seen. Epiphyseal osteomyelitis was mostly caused by salmonella infection, physeal by Corynebacterium pyogenes, salmonella and other bacteria. The salmonella affected animals were with one exception less than 12 weeks old and the majority had had some previous illness or came from a problem herd. The C pyogenes affected calves were in almost all cases more than six months old. The prognosis of the metaphyseal infection was in general satisfactory, and surgical intervention (osteotomy or sequestrectomy) was often required. The prognosis of the epiphyseal type was grave but two of the three animals in which physeal and epiphyseal defects were accompanied by diaphyseal lesions recovered.

Animals↗

PubMed1987

Bone sequestration in horses and cattle.

The site of occurrence of 490 bone sequestra in horses and cattle was investigated. Most sequestra occurred in the proximal half of the third metatarsal bone and the third metacarpal bone. The most common clinical features included swelling, presence of a draining tract, impaired function and delayed wound healing. These diagnostic features, and the preferred time to confirm the diagnosis by radiological examination are discussed. The surgical treatment is relatively simple and the prognosis favourable in most cases. It is suggested that soft tissue injury and the presence of infection are of greater importance than cortical trauma and reduced peripheral cortical circulation in the pathogenesis of sequestration.

Animals↗

PubMed1987

An induced synovitis disease model in ponies.

The effects of intra-articular injection of small amounts of E. coli lipopolysaccharide (LPS) into the intercarpal joint of 5 ponies were studied. The LPS induced predictable changes all of which were analogous to acute bacterial infection, except that the development of signs occurred sooner after the LPS injection, and subsided within 36 hours. Fever was monophasic and peaked at 5-7 hours. The ponies exhibited depression, reduced or absent appetite, increased pulse and respiration rates, and lameness. The lameness became evident between 1 and 2 hours after injection, at which time warmth, articular effusion, and resentment to palpation of joint flexion were evident. Hematological changes included neutrophilic leucocytosis, and changes in copper, iron and zinc serum concentrations. The synovial fluid total protein, leucocyte, and alkaline phosphatase levels increased within 2 hours. The mucin precipitation, total protein and leucocyte counts in synovial fluid remained elevated long after clinical and hematological changes had subsided. The model is useful for the study of some aspects of infectious joint disease.

Animals↗