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Biomedical subjects

C R Bellenger

Publications and source records attributed to C R Bellenger.

At least 19 recordsLinked to original sources
PubMed2004

Topography of the gastro-oesophageal junction in the dog revisited: possible clinical implications.

The topographical anatomy of the gastro-oesophageal junction was evaluated in six Greyhounds and six Beagles with particular emphasis on the inter-relationship of anatomic structures and landmarks. Significant variation existed between individuals, and a standard topography could not be identified. It was not possible to document the consistent presence of an intra-abdominal oesophagus in either breed examined; in the majority of cases the oesophagus was contained entirely within the thoracic cavity such that no portion of the oesophagus could be subject to abdominal pressures. This has implications for understanding the pathogenesis of hiatal hernia associated gastro-oesophageal reflux disease.

Animals↗
PubMed2003

Kinking of endotracheal tubes during maxima flexion of the atlanto-occipital joint in dogs.

Endotracheal tubes manufactured from red rubber and polyvinyl chloride (PVC) were compared, using radiographic techniques, in dog cadavers, under in vitro conditions and in anaesthetised dogs (in vivo study). All endotracheal tubes were radiographed in 'neutral' and flexed positions and the percentage reduction in the ventrodorsal radiographical diameter of the tube was calculated. The red rubber tubes kinked completely in 40 per cent of the cadavers, 75 per cent of the in vitro study and 40 per cent of anaesthetised dogs. The PVC tubes kinked completely in only one case (in vivo study). However, these tubes had a mean reduction in diameter of 15 per cent in the dog cadaver study, 19 per cent in the in vitro study and 26 per cent in the in vivo study. During procedures in which the trachea is intubated and the atlanto-occipital joint of the patient must be flexed, PVC endotracheal tubes may be less prone to kinking than red rubber tubes.

Airway Obstruction↗
PubMed2002

An avian model of limb deviation induced by periosteal surgery.

A model of limb deviation induced by hemi-circumferential periosteal stripping of the distal tibiotarsus of domestic chicks is described. This model has been developed to study the effects of periosteal stripping on the cellular, mechanical, vascular, and biochemical status of the immature bone and growth plate. It is hoped that such studies may further elucidate the mechanisms involved in altered bone growth following periosteal stripping techniques which are used in human and equine orthopaedics for the management of leg length discrepancies and angular limb deformities respectively (Auer and Martens 1980, Warrell and Baker 1987). Hemi-circumferential periosteal stripping of the left distal tibiotarsus of 28-day-old chicks resulted in significant change in metaphyseal-diaphyseal angle with time, compared to both the controls and the untreated right legs (P<0.0001). This model of limb deviation developed rapidly and consistently, and the procedures were well tolerated by the birds over the short survival time (maximum 28 days).

Animals↗
PubMed2002

Surgical management of haemangiopericytoma involving the biceps femoris muscle in four dogs.

Four dogs with haemangiopericytoma of the subcutaneous tissue overlying and infiltrating the biceps femoris muscle were successfully managed using complete resection of the involved muscle with 2 to 3 cm skin margins. Postoperatively, no local recurrence was noted in any of the dogs in a follow-up period of four to 33 months (mean 22 months). Wound dehiscence, attributed to increased tension and inadequate exercise restriction, occurred in two of the four cases. Closure of the large cutaneous deficit in the craniolateral thigh and stifle was achieved by rotation of a flank-fold skin flap in one case. Strict exercise restriction and the use of a Robert Jones dressing may prevent muscle suture disruption. These measures should enable primary wound healing in the region to progress without complication.

Animals↗
PubMed2002

Cellophane banding of congenital intrahepatic portosystemic shunts in two Irish wolfhounds.

Two three-month-old, male Irish wolfhound siblings were diagnosed with breed-typical left divisional congenital intrahepatic portosystemic shunts consistent with patent ductus venosus. The shunts were amenable to surgical dissection at a posthepatic location. Both dogs had cellophane banding for shunt attenuation. One dog was euthanased after developing post-ligation neurological dysfunction, which was refractory to treatment. The other dog survived and demonstrated shunt attenuation. Successful surgical management using cellophane banding of a patent ductus venosus has not been previously described in a large-breed dog.

Animals↗
PubMed2001

Barrier pressure at the gastroesophageal junction in anesthetized dogs.

OBJECTIVE: To evaluate the effect of body position on barrier pressure at the gastroesophageal junction in anesthetized Greyhounds and to assess alterations in barrier pressure following gastropexy. ANIMALS: 8 adult Greyhounds. PROCEDURE: Barrier pressure at the gastroesophageal junction was measured by fast (1 cm/s) and slow (1 cm/10 s) withdrawal of a subminiature strain gauge transducer through the gastroesophageal junction in 8 anesthetized dogs. The effect of body position was measured. Each dog then was placed in right-lateral recumbency, and gastropexy was performed in the left flank. Additional measurements were obtained 1, 5, 10, 20, and 30 minutes after gastropexy. RESULTS: Barrier pressure for dogs positioned in sternal recumbency (mean +/- SEM, 1.1 +/- 0.53 mm Hg) was significantly less than for dogs positioned in right lateral or left lateral recumbency. Following gastropexy, there was a steady increase in barrier pressure. Thirty minutes after gastropexy, barrier pressure was significantly higher (13.36 +/- 3.46 mm Hg), compared with the value before surgery. CONCLUSIONS AND CLINICAL RELEVANCE: Barrier pressure in anesthetized dogs is highly variable and influenced by body position. This is most likely the result of anatomic interrelationships between the diaphragm, stomach, and terminal portion of the esophagus. Gastropexy also increases barrier pressure in the immediate postoperative period, which may be clinically relevant in terms of understanding how resolution of gastroesophageal reflux disease associated with hiatal hernia may be affected by gastropexy combined with hernia reduction.

Abdominal Muscles↗
PubMed2000

Perirenal pseudocysts in 26 cats.

OBJECTIVE: To evaluate clinical features, anatomical location, nature of pseudocyst fluid, results of surgical treatment and links with underlying renal disease in cats with perirenal pseudocysts. DESIGN: A retrospective study of 26 affected cats, including 8 treated surgically. RESULTS: Nineteen (73%) affected cats were male. The median age was 11 years. Most presented for abdominal enlargement and had varying degrees of renal dysfunction on presentation. Thirteen cats (50%) had bilateral pseudocysts. The pseudocyst fluid was a transudate or modified transudate in all cases. All surgically treated cats had subcapsular perirenal pseudocysts. Associated renal lesions were identified in all cats that had renal biopsies or detailed ultrasonographic examinations. Surgery relieved clinical signs but did not stop progression of renal disease. Cats survived a median of 9 months after surgery and survival was correlated statistically to degree of azotaemia at presentation. Percutaneous drainage of pseudocysts was ineffective in controlling long-term fluid accumulation. CONCLUSIONS: Subcapsular perirenal pseudocysts are formed in cats by accumulation of transudate between the capsule and parenchyma of the kidney as a result of underlying parenchymal disease. Pseudocyst formation can occur at variable stages of renal dysfunction. Resection of the pseudocyst wall is usually effective in eliminating signs but does not stop progression of renal disease. The prognosis for cats with pseudocyst formation is related to the degree of renal dysfunction at time of diagnosis.

Animals↗
PubMed1999

Intra-abdominal cryptococcosis in two dogs.

Intra-abdominal cryptococcosis was diagnosed in two young dogs. The first, an entire male border collie, was presented with vomiting. An abdominal mass detected during physical examination proved to be cryptococcal mesenteric lymphadenitis on exploratory laparotomy. The second dog, a female neutered giant schnauzer, was presented with neurological signs suggestive of encephalopathy. Intestinal cryptococcal granulomas were detected in an extensive diagnostic investigation which included abdominal ultrasonography. The gastrointestinal tract was considered the most likely portal of entry for cryptococcal organisms in both cases. Both dogs were treated using surgery and multiagent antifungal chemotherapy. The first case succumbed despite therapy, while the second dog was treated successfully as gauged by return to clinical normality and a substantial decline in the cryptococcal antigen titre which continued to fall after cessation of treatment.

Abdomen↗
PubMed1998

Hiatal herniation as a complication of chronic diaphragmatic herniation.

Three of four cases of chronic diaphragmatic herniation seen over a period of 12 months developed hiatal herniation within five to eight days of corrective surgery for the diaphragmatic herniation. None of the dogs had shown any prior signs referrable to hiatal herniation. The features that developed subsequent to diaphragmatic herniorrhaphy in all cases were dyspnoea, increased intra-abdominal pressure due to decreased abdominal domain and laxity of the oesophageal hiatus as judged subjectively at the time of surgery for hiatal herniation correction. These conditions may be significant underlying factors for the development of hiatal herniation not preceded by diaphragmatic herniation in the dog. Those associated factors accepted as important in humans, including reduced lower oesophageal sphincter tone and gastro-oesophageal reflux, may not be of similar importance in small animals.

Accidents, Traffic↗
PubMed1997

Mechanical comparison of materials used for extra-capsular stabilisation of the stifle joint in dogs.

OBJECTIVE: The mechanical properties of three materials (No. 2 polypropylene, No. 5 polybutilate-coated multifilament polyester and 18, 27 and 36 kg test monofilament nylon leader material) commonly used for extra-capsular stabilisation of the stifle in dogs with cranial cruciate ligament insufficiency were determined. The ability of No. 5 polybutilate-coated multifilament polyester and 36 kg test monofilament nylon leader material, when placed as extra-capsular sutures, to mitigate cranial drawer was evaluated in hindlimbs of cadavers. DESIGN: An in vitro mechanical study. ANIMALS: Seven pairs of hindlimbs harvested from adult greyhound dogs recently euthanased for other reasons. PROCEDURE: Samples of each material, including samples of 27 kg test leader material that had been sterilised by one of three methods (ethylene oxide, one or five cycles in an auto-clave), were loaded to determine tensile and stress relaxation properties. The effect of cyclic loading on a No. 5 polybutilate-coated multifilament polyester and 36 kg test leader material was also determined. Using the harvested hindlimbs, cranial drawer was measured before and after transection of the cranial cruciate ligament and on the first and twelfth cycle following extra-capsular stabilisation with either No. 5 polybutilate-coated multifilament suture or 36 kg test leader material. RESULTS: Leader material was found to have the most suitable mechanical characteristics for use as extracapsular stabilisation of the cranial cruciate ligament deficient stifle. Of the sterilisation methods, ethylene oxide was found to have the least detrimental effects on the handling and material characteristics of the leader material. Stifles stabilised with 36 kg test leader material had significantly less drawer than those stabilised with No. 5 polybutilate-coated multifilament polyester suture. CLINICAL IMPLICATIONS: Monofilament nylon leader material would appear to have suitable mechanical properties for extra-capsular stabilisation of the cranial cruciate ligament deficient stifle. If possible the material should be sterilised using ethylene oxide.

Animals↗
PubMed1997

Nasopharyngeal cryptococcosis.

Naturally occurring cryptococcosis in five cats, a dog and a koala is described. Involvement of the nasopharynx was documented in all patients, and nasopharyngeal mass lesions accounted for the major presenting complaints in four. Signs referable to nasopharyngeal disease included snoring, stertor, inspiratory dyspnoea and aerophagia. Diagnoses were made by caudal rhinoscopy using a retroverted flexible endoscope, vigorous orthograde flushing with saline, or at necropsy. Concurrent cryptococcal rhinitis was present in all cases, although involvement appeared limited to the caudal nasal cavity in most cases. Typical signs of nasal cavity disease, such as sneezing and nasal discharge, were often absent. Treatment of nasopharyngeal cryptococcosis should include physical dislodgement or debulking of lesion(s) to provide immediate alleviation of upper airway obstruction, followed by systemic antifungal therapy to eliminate residual infection from the nasal cavity. Infections caused by Cryptococcus neoformans var gattii accounted for a disproportionately large number of these cases.

Animals↗
PubMed1996

Intervertebral disc reconstitution after chemonucleolysis with chymopapain is dependent on dosage.

STUDY DESIGN: The current report describes a study in beagles in which the effects of intradiscal injection of three doses of chymopapain were evaluated with respect to the reduction of disc width and reconstitution of the nucleus pulposus. OBJECTIVES: To establish an intradiscal dose of chymopapain that would achieve optimal reduction in disc height followed by maximum reconstitution of the nucleus pulposus. SUMMARY OF BACKGROUND DATA: Earlier reports of the efficacy of high and low doses of chymopapain for chemonucleolysis have provided conflicting data, and a scientific basis for an appropriate dose is lacking. METHODS: Four mature, female beagles were subjected to chemonucleolysis using three doses of chymopapain as Chymodiactin (31, 63 and 125 picokatals/disc) injected into the L2-L3, L1-L2, and L3-L4 discs. Disc widths were monitored radiographically over 32 weeks. Proteoglycans were radiolabeled by intravenous injection with Na2 35SO4 (1 mCi/kg) 24 hours before sacrifice, and their specific activities (disintegrations per minute/mg proteoglycan), hydrodynamic size, and ability to aggregate determined. RESULTS: Sixty-three picokatals of Chymodiactin produced optimal disc reconstitution after chemonucleolysis. A reduction in disc height of approximately 35% was evident within 1 month and this slowly returned to approximately 90% of the preinjection value after 32 weeks. The nucleus pulposus contained approximately 75% of the proteoglycan content of control tissues, and most of these formed aggregates with hyaluronan. Disc collagen levels remained relatively unaffected by treatment. CONCLUSIONS: This study demonstrates that an effective reduction in disc width compatible with later reconstitution of the nucleus pulposus can be achieved experimentally with an appropriate dose of chymopapain. These data clearly indicate that an optimal dose of chymopapain for chemonucleolysis in humans needs to be established.

Animals↗
PubMed1996

Topographic variation in biglycan and decorin synthesis by articular cartilage in the early stages of osteoarthritis: an experimental study in sheep.

Articular cartilage contains large molecular weight proteoglycans that aggregate with hyaluronic acid (aggrecan) and small species, particularly biglycan (dermatan sulphate proteoglycan-1) and decorin (dermatan sulphate proteoglycan-2), that do not. Mechanical stresses have been shown to profoundly influence the metabolism of aggrecan by articular chondrocytes; however, there are limited corresponding data on the metabolism of dermatan sulphate proteoglycans 1 and 2. The objective of this study was to examine the metabolism of aggrecan, biglycan, and decorin in articular cartilage from different weight-bearing areas of normal ovine stifle joints and in joints 6 months after menisectomy, a procedure that has been shown to induce early osteorthritic changes. [35S]proteoglycans synthesised by cartilage explants from eight different weight-bearing regions of unoperated and meniscectomised ovine stifle joints during 48 hours of culture were separated by size-exclusion chromatography, hydrophobic chromatography, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis and were quantitated by phosphor-screen autoradiography. The synthesis and degradation of the proteoglycans were expressed relative to the DNA content of the explants. In control joints, the cartilage exposed to high contact stress synthesised significantly less proteoglycan overall and more decorin than joint regions bearing less stress. Explants from high stress regions also released significantly greater amounts of resident proteoglycans (dimethylmethylene blue positive) into media during culture. After lateral meniscectomy, the lateral tibial and femoral cartilages showed elevated biosynthesis of both 35S-dermatan sulphate proteoglycans 1 and 2. This chondrocyte biosynthetic response was accompanied by increased catabolism of aggrecan and the release of its degradation products into culture media. These experiments revealed, in normal joints, a topographic variation in proteoglycan synthesis by articular cartilage that was related to the mechanical stress to which the tissues were subjected in vivo. This biosynthetic pattern changed when the load distribution of the joint was altered by unilateral meniscectomy. These data suggest that an altered chondrocyte phenotypic expression of proteoglycans in response to abnormal mechanical loading is an early event in osteoarthritis.

Aggrecans↗
PubMed1996

Outcomes of thoracic surgery in dogs and cats.

Records of 146 dogs and 41 cats that underwent thoracic surgery at The University of Sydney Veterinary Teaching Hospital were reviewed for age, sex, breed, disease, operation date, periods of pre- and post-operative hospitalisation, use of surgical drains and outcome. Animals were assigned to 16 disease categories, the most common being patent ductus arteriosus, traumatic diaphragmatic hernia and oesophageal foreign body in dogs and traumatic diaphragmatic hernia in cats. Differences were observed between disease categories in all the criteria examined. There were almost equal numbers of male (72) and female (74) dogs, the median (range) age was 2.0 (0.2 to 14.0) years, the median pre-operative stay was 1 (0 to 14) days, the median post-operative stay was 4 (0 to 28) days and the overall survival to discharge rate was 78%. There were 24 male and 15 female cats (sex not recorded in 2 cats). The median (range) age was 3 (0.1 to 12) years, pre-operative stay 1 (0 to 6) days, post-operative stay 5 (0 to 15) days and the overall survival to discharge rate was 85%. Causes of post-operative deaths among animals in the most common categories are recorded and discussed.

Age Factors↗
PubMed1995

Evaluation of digestive proteinases from the Antarctic krill Euphasia superba as potential chemonucleolytic agents. In vitro and in vivo studies.

Chemonucleolysis is a therapeutic procedure whereby a degradative enzyme is injected intradiscally to reduce disc height/width by depolymerisation of extracellular matrix components. This process is considered to diminish disc pressure on inflamed nerve roots, resulting in the alleviation of sciatic pain. In the present study two krill (Euphasia superba) enzyme preparations, a proteinase and an esterase preparation, were evaluated for their potential as chemonucleolytic agents. Initially, their ability to degrade several protein (azocoll, casein, proteoglycans, PGs) and peptide (CBZ-arg-4-nitroanilide, CBZ-lys-thiobenzyl ester) substrates was assessed in vitro. The krill proteinase preparation rapidly converted azocoll, casein and PGs to small peptides. Furthermore, when this degradative enzyme preparation was evaluated in vivo, a relatively low intradiscal dose (0.54 mg/disc) was found to reduce intervertebral disc widths in beagles to 48% +/- 10.5% (mean +/- SEM) of their pre-injection values within 2 weeks of administration. Moreover, the discs injected with this proteinase had reconstituted up to 80% +/- 9% (mean +/- SEM) of their pre-injection widths at the termination of the experiment (32 weeks). These data suggest that the krill protease preparation has potential as a chemonucleolytic agent which would allow disc matrix reconstitution. Conversely, the krill esterase preparation also degraded PGs, but into relatively large fragments. This limited digestion of PGs indicates that the krill esterase would be a less effective chemonucleolytic agent than the corresponding proteinase.

Animals↗
PubMed1995

Ventricular septal defect repair in a small dog using cross-circulation.

A haemodynamically significant ventricular septal defect was diagnosed in a 3-month-old male Cavalier King Charles Spaniel. A median sternotomy was performed and the 6.5 kg dog placed on cardiopulmonary bypass using pump-assisted cross-circulation. A 10 mm diameter peri-membranous ventricular septal defect was closed using a continuous suture of 4-0 polypropylene, via a 2.5 cm incision in the right ventricular outflow tract. The duration of cardiopulmonary bypass was 90 minutes. Complications in the immediate postoperative period were mild and easily managed.

Animals↗