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Biomedical subjects

A J Worth

Publications and source records attributed to A J Worth.

At least 19 recordsLinked to original sources
PubMed2005

Necrotising fasciitis associated with Escherichia coli in a dog.

CASE HISTORY: Lameness and limb pain associated with a laceration in the inner thigh of a Border Collie dog progressed over 4 days to extensive necrosis of the full-thickness of skin and subcutaneous (S/C) tissue. A successful outcome was achieved using surgical debridement and intensive supportive care, followed by limited local closure, axial pattern flap development, and free skin grafting. CLINICAL FINDINGS: Clinical findings included severe pain, depression, pyrexia and hypoalbuminaemia, and full-thickness loss of skin from the caudal thigh to the hock. Histopathologically, debrided tissue showed extensive necrosis of the dermis, adipose and muscle tissues, and the presence of numerous Gram-negative rods. Escherichia coli was cultured from deep tissue samples. DIAGNOSIS: Necrotising fasciitis (NF) associated with E. coli infection. CLINICAL RELEVANCE: NF associated with E. coli has not been previously reported in dogs. The importance of early diagnosis and surgical debridement is noted and the relevant medical literature is reviewed.

Animals↗
PubMed2005

Ectopic hepatocellular carcinoma in a dog.

CASE HISTORY: A 14-year-old neutered male Bearded Collie was presented with a history of recurrent, intermittent urinary incontinence of 7 years duration. CLINICAL FINDINGS: A large, firm, non-painful mass was found in the mid-abdominal region on palpation. Ultrasonography of the mass revealed a compartmentalised structure with mixed echogenicity, and which did not appear to be associated with any of the abdominal organs. Ultrasound-guided fine needle aspirates contained several clusters of epithelial cells with cytological features of hepatocytes. At exploratory laparotomy, the mass was found in the gastrosplenic ligament within the greater omentum. PATHOLOGICAL FINDINGS AND DIAGNOSIS: Histopathologically, the mass consisted of sheets of hepatocytes, but without the characteristic hepatic architecture. The cells showed moderate variation in nuclear size and were sometimes binucleate. A diagnosis of hepatocellular carcinoma (HCC) in the mesentery was made. CLINICAL RELEVANCE: The presence of ectopic hepatic tissue has been reported rarely in man and cats, but not in the dog. Neoplastic transformation of ectopic hepatic tissue is seen in man. This is the first report of the presentation, clinical findings and treatment of a dog with ectopic HCC.

Animals↗
PubMed2005

Radioiodide (131I) therapy for the treatment of canine thyroid carcinoma.

OBJECTIVE: To assess the efficacy of radioactive iodine treatment (131I) for canine thyroid carcinoma, as both the sole therapeutic modality and as an adjunct to surgery. DESIGN: Retrospective analysis of case records from the Gladesville Veterinary Hospital Nuclear Medicine Service, Sydney, between August 1988 and December 2001. CASE DETAILS: The records of 65 dogs with thyroid carcinoma were analysed according to therapy and outcome. Forty-three dogs received radioiodide therapy, either as the sole therapeutic modality (32) or as an adjunct to surgery (11). Radioisotope therapy consisted of one to three doses of 131I with a dose range of 555 to 1850 MBq. For analysis, dogs were divided into groups according to therapy: no treatment, surgery alone, surgery with radioiodide therapy or radioiodide therapy alone. Mode of therapy, dosage of 131I, clinical staging and age were all independently analysed according to survival to compare efficacy or predictive value respectively. RESULTS: When radioiodide therapy was used as an adjunct to surgery, median survival was 34 months. Censored median survival time for dogs that received radioiodide alone was 30 months. Dogs that did not receive treatment had a median survival of only 3 months. Log rank statistical analysis indicated that mode of therapy was significantly correlated with survival but that clinical stage of disease was not. CONCLUSION: The authors conclude that 131I therapy is effective at extending survival time, both as a sole therapeutic modality and as an adjunct to surgery, in dogs with invasive canine thyroid carcinoma. Incomplete surgical resection may not prolong survival in dogs also receiving 131I therapy, however surgical resection with curative intent should be recommended as the first line of therapy for mobile thyroid carcinomas. Radioisotope therapy can be recommended for cases where surgery alone is considered unlikely to be curative because of metastatic disease or local invasion, or for cases where surgery has been attempted but complete surgical removal has not been achieved.

Animals↗
PubMed2004

Ability to work and owner satisfaction following surgical repair of common calcanean tendon injuries in working dogs in New Zealand.

AIM: To report the long-term outcome (return to work and owner satisfaction) following surgical treatment of common calcanean tendon (Achilles tendon) injuries in working dogs in New Zealand. METHODS: Ten New Zealand Huntaway or Heading dogs (working Collies) with complete or partial tears of the common calcanean tendon, were treated using locking-loop suturing and casting, with (7) or without (3), a calcaneo-tibial screw. All dogs were actively in work on sheep or cattle farms at the time of injury, and return to work was the desired outcome. Ability to work and owner satisfaction were investigated using a telephone questionnaire at a mean followup interval of 14.6 months. RESULTS: Overall, 7/10 dogs returned to full or substantial levels of work. Post-operative complications occurred in two dogs that did not return to full or substantial levels of work. Moderate persistent lameness (score 3 on a scale of 0-5) was present in 2/7 dogs that returned to full or substantial levels of work, equating to a 71% good-to-excellent functional outcome within this group. Seven owners felt the financial investment in opting for surgical repair was worthwhile. A screw and cast method of rigid immobilisation was thought to be superior to casting alone. CONCLUSIONS: Surgical treatment of common calcanean tendon injury in working dogs carries a good prognosis if an appropriate tenorrhaphy technique is used and rigid immobilisation is achieved for 6 weeks. Care must be taken to limit post-operative complications. CLINICAL RELEVANCE: This study justifies the use of surgical repair of such injuries in the working dog even when return to work is the only acceptable outcome.

Journal Article↗
PubMed2004

Post-traumatic paraureteral urinoma in a cat.

A retroperitoneal urinoma (uriniferous pseudocyst) was diagnosed in a domestic shorthair cat exhibiting a sublumbar swelling two weeks after a road traffic accident. Plain radiography revealed a soft tissue opacity in the left retroperitoneal space. Intravenous urography and fine-needle aspiration were diagnostic. Contrast was seen pooling in the dilated ipsilateral renal pelvis and proximal ureter. Fluid aspirated from the retroperitoneal space had a creatinine level five times that of serum. Surgical drainage followed by nephrectomy and omentalisation of the pseudocyst was curative.

Accidents, Traffic↗
PubMed2001

Qualitative and quantitative evaluation of six algorithms for correcting intensity nonuniformity effects.

The desire to correct intensity nonuniformity in magnetic resonance images has led to the proliferation of nonuniformity-correction (NUC) algorithms with different theoretical underpinnings. In order to provide end users with a rational basis for selecting a given algorithm for a specific neuroscientific application, we evaluated the performance of six NUC algorithms. We used simulated and real MRI data volumes, including six repeat scans of the same subject, in order to rank the accuracy, precision, and stability of the nonuniformity corrections. We also compared algorithms using data volumes from different subjects and different (1.5T and 3.0T) MRI scanners in order to relate differences in algorithmic performance to intersubject variability and/or differences in scanner performance. In phantom studies, the correlation of the extracted with the applied nonuniformity was highest in the transaxial (left-to-right) direction and lowest in the axial (top-to-bottom) direction. Two of the six algorithms demonstrated a high degree of stability, as measured by the iterative application of the algorithm to its corrected output. While none of the algorithms performed ideally under all circumstances, locally adaptive methods generally outperformed nonadaptive methods.

Algorithms↗
PubMed2000

Ten years of breast screening in the Screening Mammography Program of British Columbia, 1988-97.

OBJECTIVES: To evaluate 10 years outcomes of the Screening Mammography Program of British Columbia (SMPBC) and determine if breast screening targets were being achieved among women aged 40-80+ years. SETTING: Organised breast screening programme in British Columbia, Canada. METHODS: Rates of participation, abnormal referral, cancer detection, and interval cancer were calculated for asymptomatic women receiving an SMPBC mammography from 1988-97. RESULTS: 895,849 screening mammographies were provided to 335,433 women. 51.3% of women were age 50-69 years. Abnormalities were identified on 57,454 screens (6.4%) from which 3304 cancers were detected. Abnormal call rates were higher on first (9.8%), compared with subsequent screens (4.4%) and declined with age: 7.7% at age < 40 to 5.4% for age 70-79 years. Cancer detection rates were higher on first (5.0 per 1000) compared with subsequent screens (2.8 per 1000) and increased smoothly with age from 1.4 to 8.2 per 1000 from age < 40 to age 80 years and older. Twenty per cent of cancers were non-invasive. The median size of invasive cancers was 14 mm and 81% had no axillary lymph node metastases. The 12 month interval cancer rate was 0.6 per 1000 and did not vary significantly with age or screening history. The prevalence to expected incidence ratio was 3.1 for women age 50-79 years. CONCLUSION: Across a broad range of ages, surrogate indices of screening mammography success have been achieved in a population based, North American, organised breast cancer screening programme.

Adult↗
PubMed1998

Semiautomatic segmentation of brain exterior in magnetic resonance images driven by empirical procedures and anatomical knowledge.

This work demonstrates encouraging results for increasing the automation of a practical and precise magnetic resonance brain image segmentation method. The intensity threshold for segmenting the brain exterior is determined automatically by locating the choroid plexus. This is done by finding peaks in a series of histograms taken over regions specified using anatomical knowledge. Intensity inhomogeneities are accounted for by adjusting the global intensity to match the white matter peak intensity in local regions. Automated results are incorporated into the established manually guided segmentation method by providing a trained expert with the automated threshold. The results from 20 different brain scans (over 1000 images) obtained under different conditions are presented to validate the method which was able to determine the appropriate threshold in approximately 80% of the data.

Brain↗
PubMed1998

Precise segmentation of the lateral ventricles and caudate nucleus in MR brain images using anatomically driven histograms.

This paper demonstrates a time-saving, automated method that helps to segment the lateral ventricles and caudate nucleus in T1-weighted coronal magnetic resonance (MR) brain images of normal control subjects. The method involves choosing intensity thresholds by using anatomical information and by locating peaks in histograms. To validate the method, the lateral ventricles and caudate nucleus were segmented in three brain scans by four experts, first using an established method involving isointensity contours and manual editing, and second using automatically generated intensity thresholds as an aid to the established method. The results demonstrate both time savings and increased reliability.

Adult↗
PubMed1997

Morphometry of in vivo human white matter association pathways with diffusion-weighted magnetic resonance imaging.

The precise characterization of cortical connectivity is important for the understanding of brain morphological and functional organization. Such connectivity is conveyed by specific pathways or tracts in the white matter. Diffusion-weighted magnetic resonance imaging detects the diffusivity of water molecules in three dimensions. Diffusivity is anisotropic in oriented tissues such as fiber tracts. In the present study, we used this method to map (in terms of orientation, location, and size) the "stem" (compact portion) of the principal association, projection, and commissural white matter pathways of the human brain in vivo, in 3 normal subjects. In addition, its use in clinical neurology is illustrated in a patient with left inferior parietal lobule embolic infarction in whom a significant reduction in relative size of the stem of the left superior longitudinal fasciculus was observed. This represents an important method for the characterization of major association pathways in the living human that are not discernible by conventional magnetic resonance imaging. In the clinical domain, this method will have a potential impact on the understanding of the diseases that involve white matter such as stroke, multiple sclerosis, amyotrophic lateral sclerosis, head injury, and spinal cord injury.

Cerebral Cortex↗
PubMed1997

Post screen-detected breast cancer within the Screening Mammography Program of British Columbia.

The histological characteristics and extent of mammographic density were compared between 170 post screen-detected (PSD) breast cancers and 466 screen-detected (SD) breast cancers in women attending the Screening Mammography Program of British Columbia. In addition, methods of detection and clinical presentation for the PSD cancers were examined. Invasive ductal, comedo, and medullary carcinoma were significantly more common in PSD cancer in women under age 50 years, and invasive ductal carcinoma in women over age 50 years. Mammographic density was more common in PSD cancers for all age groups under 70 years. The majority of PSD cancers were node negative with no evidence of metastases; however, they tended to be of more advanced stage than SD cancer. Most PSD cancers regardless of age were initially found by the woman herself, presenting as a palpable mass, and the likelihood of being detected within 12 months of the last screening mammogram was higher at younger ages.

Age Factors↗
PubMed1997

Nitrite poisoning in cats and dogs fed a commercial pet food.

The death of three cats, from two separate households, was linked to toxic concentrations of sodium nitrite used as a preservative in a commercial pet food. Post-mortem examination of the three cats revealed a brownish discoloration of the blood suggestive of methaemoglobinaemia. Analysis of two samples of the pet food fed to the cats revealed a mean concentration of 2850 mg of total nitrite per kg of food (as fed). In a further incident, ataxia and weakness was noticed in two of four dogs after they were fed the same brand of pet food. One dog was successfully treated for methaemoglobinaemia with intravenous methylene blue.

Journal Article↗
PubMed1994

Interval breast cancers in the Screening Mammography Program of British Columbia: analysis and classification.

OBJECTIVE: Interval cancers in an annual mammography screening program are defined as cancers detected within 12 months after a mammographic screening in which findings are considered normal. Our objective was to analyze interval cancers for histologic type, tumor size, staging, and histologic grade. A classification for interval cancers is presented. Detection of interval cancers is an integral part of quality control and is required for the establishment of sensitivity rates for screening mammography, a necessary part of implementing the recommendations for breast cancer screening. MATERIALS AND METHODS: A total of 47,583 mammographic screening examinations of 38,219 women were available for review for the period of July 1988 to March 1991. Linkage with the provincial population-based cancer registry provided identification of all interval cancers of the breast. Histologic analysis of breast cancers was provided by an internationally recognized breast cancer pathologist who interpreted the specimens twice. RESULTS: A total of 207 breast cancers were detected at mammographic screening (true-positive cancers) during the first 33 months of the program, and 37 interval cancers were identified during the 33 months of screening plus a 12-month interval. Blinded review by three radiologists experienced in screening mammography resulted in classification of 21 of 37 cases as true interval cancers and 16 cases as misses. No interval cancers were missed because of poor mammographic technique. The sensitivity of screening mammography was 85%, 63% for patients less than 50 years old and 89% for patients more than 50 years old. The specificity was 93% for all patients (both younger and older than 50 years). CONCLUSION: The availability of a population-based cancer registry in the province of British Columbia makes an accurate determination of interval cancers and sensitivity rates possible. These data are essential for quality analysis, program planning, and education of radiologists in screening mammography. There were more true interval cancers than misses, and histologic analysis demonstrated that the majority of interval cancers were in stages I and II.

Adult↗
PubMed1991

Detection of micrometastases from primary breast cancer.

The monoclonal antibody LICR-LON-M8 was used in a series of experiments to determine how an immunohistochemical technique could be used as a diagnostic test for micrometastatic disease in patients with operable, primary breast carcinoma. Optimal tissue and antigen preservation was obtained with fixatives containing either picric acid or a heavy metal such as mercury to allow staining with the monoclonal antibody diluted to 1:12,000 to 1:16,000 from unpurified mouse ascites. Tissue affected by primary and metastatic disease stains in a characteristic fashion, which is distinct from benign breast tissue. All the ductal tumours stained positively for malignant cells with the monoclonal antibody preparation. Within the bone marrow, occasional granulocytes and granulocyte precursors stained positively if the endogenous peroxidase activity was incompletely blocked. These cells were readily differentiated from tumour cells on cytologic examination. With these monoclonal antibody and immunohistochemical staining techniques it may now be possible to detect early micrometastatic disease in the bone marrow of patients with primary breast cancer.

Antibodies, Monoclonal↗
PubMed1991

Monoclonal antibody LICR-LON-M8 does not predict the outcome of operable breast cancer.

The prognostic value of the monoclonal antibody LICR-LON-M8, which has been shown to detect micrometastatic disease, was evaluated in a prospective, double-blind, clinical study of bone-marrow specimens from patients with operable breast cancer. Four bone-marrow specimens, obtained from each of 50 patients at the time of excision of the primary breast tumour, were examined immunohistochemically, with LICR-LON-M8 as the primary antibody. All of the primary tumour specimens demonstrated positive staining for malignant disease with LICR-LON-M8. The bone-marrow specimens of four patients demonstrated positive staining: three specimens were "suspicious" for malignant cells and one contained definite malignant cells on cytologic examination. This gave a 2% rate of detectable micrometastatic disease at the time the primary tumour was excised. Patient follow-up averaged 21.5 +/- 9.1 months. The test results did not correlate with outcome. A negative test result with LICR-LON-M8 did not imply a better prognosis. The authors conclude that examination of bone-marrow specimens stained with LICR-LON-M8 in patients with operable breast cancer is of no clinical value. Furthermore, the low rate of micrometastases detected is at variance with that reported by others. In view of the natural history of breast cancer, the authors believe that their results were not unexpected and they question the importance of other results.

Adult↗
PubMed1990

Human papillomavirus and cervical intraepithelial neoplasia in women who subsequently had invasive cancer.

In a retrospective case-control study biopsy specimens of cervical intraepithelial neoplasia (CIN) lesions from 47 women in whom invasive cancer subsequently developed (cases) and from 94 control subjects in whom CIN was diagnosed within 6 months of the diagnosis for the matched case subject but invasive disease did not develop were tested for human papillomavirus (HPV) DNA with tissue in-situ hybridization. There were no significant differences in the frequency of detection of HPV DNA between the two groups. In a cross-sectional survey the prevalence of HPV DNA was found to be 11% in specimens without CIN, 27% in those with CIN I, 49% in those with CIN II and 56% in those with CIN III. The positivity rates for HPV 16/33 DNA increased with the severity of CIN, but this was not observed for HPV 6/11 and 18 DNA. A comparison of the results of the case-control and cross-sectional studies suggested that the younger cohort of women had higher prevalence rates of HPV DNA than the older cohort.

Adolescent↗
PubMed1990

Diet and histologic types of benign breast disease defined by subsequent risk of breast cancer.

The authors investigated the relation between diet and histologic types of benign breast disease defined by subsequent risk of breast cancer in a case-control study of volunteers who entered the Vancouver Center of the Canadian National Breast Screening Study between 1983 and 1985. Proliferative benign breast disease (n = 124) was inversely associated with vitamin A supplementation (vitamin A user vs. nonuser, odds ratio (OR) = 0.5) and frequent green vegetable consumption (frequent vs. rare consumption, OR = 0.3), whereas severe atypias and borderline carcinoma in situ (n = 32) were directly associated with frequent meat fats consumption (frequent vs. rare consumption, OR = 3.2) with no association with vitamin A or vegetable consumption. No dietary relations were found for histologic types of benign breast disease at no increased risk for subsequent breast cancer (n = 274). The implications of these findings in relation to the etiology of breast cancer are discussed.

Breast Neoplasms↗