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Biomedical subjects

R N White

Publications and source records attributed to R N White.

At least 37 records · Page 2Linked to original sources
PubMed1997

Surgical management of subvalvular aortic stenosis and mitral dysplasia in a golden retriever.

A 12-month-old neutered male golden retriever was presented with a history of lethargy and exercise intolerance. Clinical examination, electrocardiography, radiography and echocardiography supported a diagnosis of fixed subvalvular aortic stenosis with a Doppler pressure gradient of 77.5 mmHg. Surgical inspection also revealed gross structural abnormalities of the mitral valve consistent with mitral dysplasia. Intervention consisted of resection of the dysplastic mitral valve and the subvalvular aortic stenosis. The mitral valve was replaced with a bioprosthetic valve. Total cardiopulmonary bypass time was 65 minutes and aortic cross-clamp time was 55 minutes. A full recovery was made and 11 months postoperatively the aortic transvalvular gradient was 30 mmHg. At the time of writing, 12 months after surgery, the dog was clinically normal and requires no medication.

Animals↗
PubMed1997

Resolution of exfoliative dermatitis and Malassezia pachydermatis overgrowth in a cat after surgical thymoma resection.

A four-year-old, male neutered domestic shorthaired cat was presented with a two-week history of nasal and ocular discharge, generalised exfoliative dermatitis, intense pruritus, polydipsia, polyphagia, weight loss, intermittent hindlimb ataxia and lethargy. Cutaneous populations of Malassezia pachydermatis yeast organisms were found to be elevated. The generalised nature of the disease prompted survey radiography which revealed the presence of a cranial mediastinal mass which was subsequently resected and found to be a thymoma. Within six months of surgery, systemic and cutaneous signs had resolved and yeast counts had returned to normal, suggesting a causal relationship between the thymoma and the skin disease.

Animals↗
PubMed1997

Arteriovenous fistula involving the prepuce of a dog.

A nine-year-old male Ibizan hound had a network of large tortuous pulsating blood vessels on the prepuce that enlarged gradually over a five month period. A diagnosis of arteriovenous fistula was based on clinical signs, angiography and Doppler ultrasonography. Ligation of the major vascular supply to the fistula resulted in only temporary improvement. Definitive treatment was by wide excision, with penile amputation and scrotal urethrostomy.

Angiography↗
PubMed1997

Chronic caecal faecolithiasis in a dog.

A 14-year-old, spayed female Jack Russell terrier with a six month history of weight loss, lethargy, intermittent vomition and diarrhoea was diagnosed as having a chronic impaction of the caecum with mineralised faecal material. Diagnosis was based on the clinical findings and both survey and positive contrast radiographic studies. The diagnosis of caecal impaction was confirmed at surgery and a typhlectomy was performed with the aid of a linear stapler. Histopathology of the caecum confirmed the impaction to have resulted from faecolithiasis. The dog made a full recovery from the procedure, showing no recurrence of the clinical signs until euthanasia three months postoperatively for probable heart failure associated with mitral regurgitation.

Animals↗
PubMed1997

Naturally occurring xanthine urolithiasis in a domestic shorthair cat.

A five-year-old neutered male domestic shorthair cat was presented after three episodes of urethral obstruction and anuria requiring relief urethral catheterisation. A double contrast cystogram revealed the presence of multiple small cystoliths which were radiolucent on plain radiographs. A perineal urethrostomy and a cystotomy were performed to relieve the urethral obstruction and to remove the cystoliths. Quantitative analysis revealed the cystoliths to be composed of 100 per cent xanthine. Clinical history suggested the xanthinuria to be naturally occurring. Unfortunately, the cat was killed in a road traffic accident two months after the surgical procedure, preventing further long-term assessment.

Animals↗
PubMed1996

Surgical treatment of intrahepatic portosystemic shunts in six cats.

The surgical treatment of intrahepatic portosystemic shunts in six cats is described. The preoperative diagnoses were based on the results of abdominal ultrasonography, and mesenteric portography was used during surgery to confirm the diagnosis and establish the morphology of the shunting vessel. In four of the cats the shunt vessel passed through the left division of the liver, compatible with a patent ductus venosus (PDV), in one cat the shunt passed through the central hepatic division and in the other cat it passed through the right hepatic division. During surgery the shunt vessel was manipulated directly either intrahepatically, or post hepatically in the four cats with PDV. In five cats the shunt vessel was partially ligated, and in the other the vessel was completely ligated. The attenuation procedure produced a mean increase in mesenteric venous pressure of 17 cm H2O, with a range from 14 to 20 cm. All the cats recovered from the surgical procedure, but one developed neurological signs shortly after the operation and died from respiratory failure. Four of the cats were clinically normal and required no medication by one month after the operation. One cat required long-term medication to control its continued clinical signs.

Animals↗
PubMed1996

Ultrasonographic diagnosis of congenital portosystemic shunt in 14 cats.

Twenty-four cats with clinical and, or, clinicopathological signs compatible with portosystemic shunting were examined prospectively using two-dimensional grey-scale, duplex and colour-flow Doppler ultrasonography. Diagnosis of congenital portosystemic shunt was subsequently confirmed in 14 cats using operative mesenteric portography and surgery. Of the 14 affected cats, nine were purebred; eight were male and six female. The mean age at the time of diagnosis was nine months (range four to 27 months). Ultrasonographic evidence of a small liver was present in seven cats (50 per cent); visibility of intrahepatic portal vessels was reduced in three (21 per cent). An anomalous blood vessel was identified ultrasonographically in each cat; in 10 cats (71 per cent) the vessel was observed to originate from the portal vein and drain into the caudal vena cava. Abnormally variable portal blood flow was present in eight of the 10 cats in which it was measured. At surgery, six shunts were intrahepatic and eight extrahepatic; the ultrasonographic diagnosis of intra- versus extrahepatic shunt was correct in 13 cats (93 per cent). No anomalous blood vessels or abnormalities affecting the portal vein were detected ultrasonographically in any of the 10 cats that did not have congenital portosystemic shunting. Hence, the accuracy of ultrasonography for diagnosis of congenital portosystemic shunting in this series was 100 per cent.

Animals↗
PubMed1996

Per rectal portal scintigraphy in the diagnosis and management of feline congenital portosystemic shunts.

Five cats with a congenital portosystemic shunt (CPSS) were examined using transcolonic portal scintigraphy before and after surgical ligation of the shunting vessel. The mean shunt index before surgery was 52 per cent (range 45 to 61 per cent). Repeat portal scintigraphy, six to eight weeks after surgery, indicated a significant reduction in shunt index (mean 13 per cent, range 5 to 25 per cent) in four cats. In one of these cats a marked reduction in the shunt index, as determined by scintigraphy, preceded normal fasting blood ammonia. In the fifth cat there was no significant change in the shunt index, fasting serum bile acids and blood ammonia six months after surgery, although its clinical signs of hepatic encephalopathy had improved. Portal scintigraphy is useful in the diagnosis of CPSS and enables a quantitative assessment of the effects of surgery and may be a more accurate indicator of the degree of shunting after surgery than blood ammonia and serum bile acids.

Ammonia↗
PubMed1996

Review of the technique and complications of median sternotomy in the dog and cat.

The surgical and medical records of 67 dogs and nine cats which underwent median sternotomy over a five-year period were reviewed. The indication for median sternotomy and the short and longer term complications were recorded. Twenty-six of the dogs died or were euthanased within 48 hours of the surgery as a consequence of the pre-existing disease or complications of the intrathoracic surgical procedure. A further four dogs were enthanased between 48 hours and 14 days following confirmation of neoplastic processes. Thirty-seven dogs were alive at 14 days: of these, seven dogs (19 per cent) experienced short-term wound complications, including haemorrhage, wound infection, thoracic limb neurological deficits and excessive postoperative discomfort. Of the 37 dogs alive for longer term follow-up, eight dogs (22 per cent) experienced wound complications, including haemorrhage, sternal fracture, sternal osteomyelitis and delayed wound healing. No complications were noted in the cats.

Animals↗
PubMed1996

Treatment of acquired myasthenia gravis associated with thymoma in two dogs.

Two cases of myasthenia gravis associated with thymoma are reported. Both were female German shepherd dogs and the thymoma was surgically resected. Aspiration pneumonia secondary to persistent megaoesophagus was a complication in both cases. The myasthenia gravis did not resolve, but there was a more satisfactory control of clinical signs with anticholinesterase treatment. Corticosteroid therapy was used in one case, but the resulting polydipsia increased the incidence of regurgitation, resulting in recurrent episodes of aspiration pneumonia.

Adrenal Cortex Hormones↗
PubMed1995

Unilateral arytenoid lateralisation and extraluminal polypropylene ring prostheses for correction of tracheal collapse in the dog.

The surgical repair of tracheal collapse in 25 dogs is described. The initial presenting signs included coughing, dyspnoea, gagging, retching, exercise intolerance, cyanosis and collapse. Diagnosis was based upon the clinical signs, plain radiography and tracheal endoscopy. The collapse was corrected by the application of a number of extraluminal polypropylene prosthetic rings applied to the affected trachea. Additionally, a left arytenoid lateralisation was also performed. The perioperative complication rate was approximately 4 per cent, while the success rate was 75 per cent. The technique reduces the likelihood of catastrophic postoperative complications associated with iatrogenic laryngeal paralysis which is a possible complication of placement of extraluminal tracheal support devices.

Animals↗
PubMed1995

Intrathoracic tracheal avulsion in three cats.

The surgical repair of complete intrathoracic tracheal avulsion in three cats is described. The initial presenting signs included dyspnoea, exercise intolerance and exertional cyanosis. Diagnosis was based upon the clinical signs, survey radiography and tracheal endoscopy. The ruptures were repaired via a right lateral thoracotomy made at the third or fourth intercostal interspace. Abnormal trachea was resected and a standard tracheal anastomosis was performed. Surgical results were considered excellent in all cases.

Anastomosis, Surgical↗
PubMed1995

Mitral valve replacement for the treatment of congenital mitral dysplasia in a bull terrier.

A 10-month-old entire male bull terrier was presented with a history of collapse on exercise. Clinical examination, electrocardiography, radiography and echocardiography all supported a diagnosis of mitral valve dysplasia. There was no evidence of congestive heart failure. Surgical intervention consisted of open resection of the dysplastic mitral valve and its replacement with a bioprosthetic valve. The procedure was performed through a median sternotomy and the dog was placed on to full cardiopulmonary bypass. Total cardiopulmonary bypass time was 70 minutes. A full recovery was made and at the time of writing (17 months postoperatively) the dog is clincally normal requiring no medication.

Animals↗
PubMed1993

An application of sinography in small animal practice.

Sinography is a well recognised aid to clinical diagnosis in human medicine; it is used in equine practice but is less commonly used in small animal practice. The technique was used to investigate four dogs with sinuses associated with radiolucent foreign bodies secondary to penetration wounds.

Animals↗
PubMed1988

The effect of temperature on myogenesis in embryonic development of the Atlantic salmon (Salmo salar L.).

From fertilisation to hatching one group of salmon embryos was reared at ambient temperatures (fluctuating around 1.6 degrees C) and another at 10 degrees C. At Gorodilov stages 28, 30 and 33 transverse sections of whole embryos were obtained for light and electron microscopy. Total cross-sectional areas, fibre numbers, fibre diameters and myofibrillar areas of the white muscle of m. lateralis were measured. At hatching (stage 33, which occurred much earlier at the higher temperature), the higher temperature embryos had significantly larger (P less than 0.01) but fewer (P less than 0.05) muscle fibres. These larger fibres contained significantly more myofibrillar material (P less than 0.05) than the smaller fibres of the lower temperature embryos. Lesser differences were found at pre-hatching stages. Higher temperatures caused myofibre hypertrophy to increase at a greater rate than hyperplasia. Hence, the cellularity of the tissue produced under the different temperature regimes was quite different.

Animals↗
PubMed1983

Evaluation of a curb-climbing aid for manual wheelchairs: considerations of stability, effort, and safety.

The experimental and theoretical procedures used to gather ergonomic data and derive theoretical estimates of stability, effort, and safety in use of a curb-climbing aid for standard manual wheelchairs are presented. The aid, intended for use of paraplegic persons, employs ramps which the user while seated in the chair can deploy and retrieve using attached telescoping rods. Ramps and rods may be carried in a ready-for-use position or stowed away in a bag hung behind the wheelchair backrest. Design, construction and method of use were described in White RN, Szeto AYJ, and Hogan HA: A practical curb-climbing aid for wheelchair-bound paraplegic patients (a progress report) Bull Prosth Res BPR 10-34 17(2):13-19 Fall 1980.

Architectural Accessibility↗