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Biomedical subjects

C R Lamb

Publications and source records attributed to C R Lamb.

At least 19 recordsLinked to original sources

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

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

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

Ultrasound-guided catheter biopsy of the lower urinary tract: technique and results in 12 dogs.

Ultrasound-guided catheter biopsy of lesions affecting the lower urinary tract was attempted in 12 dogs with mucosal lesions affecting the bladder (nine) or urethra (three). Histological biopsies were obtained by catheter biopsy in 10 dogs, enabling diagnosis of transitional cell carcinoma in five, papilloma in two, prostatic carcinoma in two and chronic cystitis in one. Cytological samples alone were obtained in two dogs, one of which enabled a diagnosis of transitional cell carcinoma; the other contained evidence of haemorrhage and inflammation, but squamous cell carcinoma was found in a subsequent excisional biopsy. Intravesicular haemorrhage after biopsy was observed ultrasonographically in two dogs. Ultrasound guidance enables accurate determination of biopsy catheter position. The size of biopsies obtained by this method may limit the accuracy of histological diagnosis.

Animals

Ultrasonography of pancreatic neoplasia in the dog: a retrospective review of 16 cases.

The history, clinical signs and radiographic and ultrasonographic findings in 16 dogs with pancreatic neoplasia were reviewed retrospectively. Thirteen of the dogs had islet cell carcinoma compatible with insulinoma, one had a pancreatic adenocarcinoma and two had secondary invasion of the pancreas, one by a gastric carcinoma and one by an intestinal lymphoma. The clinical signs in the 13 dogs with insulinoma included collapse in 10 dogs, ataxia in seven, weakness in five, and seizures in two. Two of the 16 dogs had jaundice due to biliary obstruction by the primary tumour or metastases. The sensitivities for pancreatic neoplasia were three of 16 (19 per cent) for radiography and 12 of 16 (75 per cent) for ultrasonography; the sensitivities for metastasis were two of 11 (18 per cent) for radiography and six of 11 (55 per cent) for ultrasonography. Biliary obstruction was detected by ultrasonography in both affected dogs.

Adenocarcinoma

Cholecystokinin-8 induces edematous pancreatitis in dogs associated with short burst of trypsinogen activation.

To study the early pathogenesis of acute edematous pancreatitis in dogs, we examined the relationship of pancreatic hyperstimulation with cholecystokinin-8 (10 micrograms/kg/hr intravenously for 6 hr) to alterations in circulating pancreatic enzymes and pancreatic morphology with special reference to trypsinogen activation. Cholecystokinin-8 infusion was associated with increases in plasma amylase, lipase, trypsin-like immunoreactivity, and plasma and urine trypsinogen activation peptide. Pancreatic parenchymal swelling and interlobular and subcapsular fluid accumulations were detected ultrasonographically within 2 hr of cholecystokinin-8. Circulating trypsin-like immunoreactivity and trypsinogen activation peptide in urine reached a peak at 2 and 4 hr, respectively, then declined despite progressive increases in circulating amylase and lipase and intrapancreatic fluid. No significant changes were observed in dogs receiving a saline infusion. This study illustrates that cholecystokinin-8 induces edematous pancreatitis in dogs that is associated with a short-lived burst of trypsinogen activation.

Acute Disease

Osteomyelitis and disseminated infection caused by Corynebacterium renale in a goat.

A 1.5-year-old female goat was examined for recurrence of lameness involving the right forelimb. Radiography of the thorax and right scapulohumeral joint revealed a pathologic fracture of the supraglenoid tubercle, and circumscribed radiolucent lesions in the right third and fourth ribs, and the base of the spinous process of T3. Bone scintigraphy demonstrated additional lesions in the lumbar spine and the wings of the ilium. At necropsy, disseminated infection and hematogenous osteomyelitis were diagnosed. Corynebacterium renale was cultured from the rib lesions. In food animals, osteomyelitis usually develops secondary to traumatic wounds, and members of the genus Actinomyces are frequently incriminated as the causative organism. This case is unusual because the osteomyelitis was unrelated to a traumatic wound, and the gross and microscopic lesions were reminiscent of caseous lymphadenitis, an infection caused by C pseudotuberculosis.

Animals

Ultrasonography of the ureterovesicular junction in the dog: a preliminary report.

Contrast radiography followed by ultrasonography of the urinary bladder was performed on 10 incontinent dogs. The ureterovesicular junctions and ureteral jets were identified by ultrasonography in all the dogs except one that had a caudally displaced bladder. An ectopic ureter in one dog was diagnosed by ultrasonography on the basis of the absence of a ureteral jet on the affected side, and the direct identification of the ureter passing caudal to the bladder neck. Ultrasonography appears to be a simple, repeatable test for identifying the distal ureters.

Animals

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

Contrast radiography of equine joints, tendon sheaths, and draining tracts.

Arthrography, tenography, and fistulography (or sinography) can provide additional information about the soft-tissue components of joints, tendon sheaths, and draining tracts, respectively. Arthrography is a valuable aid in the diagnosis of synovial masses, such as villonodular synovitis, and osteochondrosis. Tenography is particularly useful in evaluating chronic tendon sheath distention. Fistulography is an effective means of identifying acute traumatic damage to synovial structures and determining the cause and extent of draining tracts.

Animals

Ultrasonography of the liver and biliary tract.

Evaluation of the liver and biliary tract is one of the principal applications of abdominal ultrasonography in small animals. Indications include hepatomegaly, mass in the area of the liver, suspected hepatic metastasis, jaundice, ascites, suspected diaphragmatic rupture, and weight loss. Ultrasonography is a valuable method for evaluating the internal structure of the liver and biliary tract. Certain functional assessments also may be made, for example, measurement of induced gallbladder emptying after cholecystokinin injection. Limitations of ultrasonography include lack of specificity for focal or multifocal hepatic lesions and insensitivity for certain infiltrative diseases, such as lymphosarcoma. These limitations contribute to diagnostic difficulties, which are adequately addressed only by biopsy. The technique of ultrasound-guided biopsy is described briefly.

Animals

Bronchial dysgenesis and lobar emphysema in an adult cat.

An adult male cat was examined because of chronic respiratory tract disease. Results of thoracic radiography indicated overinflation of the right lung, and atelectasis or agenesis of the left lung. Notable aerosol deposition (ventilation) to the right caudal lung lobe was seen by use of pulmonary ventilation scintigraphy. Postmortem findings suggested the primary pathoanatomic lesion was bronchial dysgenesis involving all but the right caudal lung lobe.

Animals

Preoperative measurement of canine primary bone tumors, using radiography and bone scintigraphy.

Specimens of 20 canine primary bone tumors (18 osteosarcoma, 2 fibrosarcoma) were examined to compare the maximal axial length of gross tumor with the length of the lesion seen on preoperative radiographs and 99mTc methylene diphosphonate bone scintigraphic images. Radiographs defined the length of the tumor to within +/- 10% of the gross measurement for 6 (30%), underestimated it for 12 (60%), and overestimated it for 2 (10%) specimens. Bone scintigraphy defined tumor length within +/- 10% for 8 (40%), underestimated it for 1 (5%), and overestimated it for the remaining 11 (55%) specimens. Use of radiographic evaluation alone could result in underestimation of the diaphyseal extent of a primary bone tumor, with risk of incomplete resection. Bone scan images tend to overestimate tumor length and, therefore, may provide safer resection guidelines.

Animals