Cell renewal and gene expression in the trachea of hamster at different ages.

The tracheal mucosa of the Syrian golden hamster has been extensively employed as a model system for respiratory tract cell renewal, injury, and carcinogenesis. However, baseline cell kinetic data are not available for normal juvenile and adolescent animals in which the mucosa and cartilage are rapidly enlarging. The objective of this research was to elucidate alterations in cell kinetics, epithelial morphology, and gene expression in the trachea of hamsters at different ages. Cell kinetics were examined by 3H-thymidine labeling indices, morphology by light and electron microscopic examination, and gene expression by slot blot analysis. Results showed that mucosal epithelium of the young and adolescent hamster undergoes cyclic necrosis and cell shedding, exposing portions of the elastic basal lamina. Epithelial shedding was associated with hyperplasia and squamous metaplasia. Additionally, the labeling indices of mucosal epithelial cells and chondroblasts also exhibited variable patterns which were associated with a cyclic pattern of expression of c-fos and c-erbB2 proto-oncogenes and epidermal growth factor receptor.     

Chronic subdural haematoma associated with nontraumatic CSF rhinorrhea: a management challenge.

We report an unusual case of chronic subdural haematoma (CSH) associated with cerebrospinal fluid (CSF) rhinorrhoea emphasizing the importance of managing both conditions simultaneously. A 59- year-old man presented with watery discharge from the right nostril, of 2 months duration. MRI of the brain showed a CSH in the left fronto-parietal region with significant mass effect. There was an arachnoidocoele with a defect in the planum sphenoidale. He first underwent a burr hole evacuation of the CSH following which the CSF rhinorrhea did not subside, even with bed rest. Transnasal endoscopic closure of the CSF dural fistula was done. On the first post-operative day, he was disoriented and a CT scan showed a recollection of the subdural haematoma that required repeat evacuation. The patient was asymptomatic at discharge. To our knowledge this is the first reported case of CSF rhinorrhoea associated with CSH. Simultaneous closure of the CSF dural fistula at the time of evacuation of a coexisting CSH would be the optimal management.     

Implementation of a successful endovascular surgical program in a non-teaching tertiary-care centre in Ontario.

Endovascular surgical techniques have become an accepted standard of care for high-risk patients with abdominal aortic aneurysms and for certain patients with thoracic aortic pathology and peripheral arterial aneurysms. In Canada, endovascular surgery has been concentrated in tertiary-care academic teaching institutions. As the technology evolves and as expertise advances, the applicability of endovascular techniques will expand. With time, and as the demand for endovascular techniques rises, this expertise will increasingly need to be delivered by dedicated vascular surgical services in nonteaching institutions. The dissemination of endovascular surgical capabilities represent a unique challenge. We report the successful implementation of an endovascular surgical program in a tertiary-care nonteaching institution using a carefully planned preceptorship model. We review our initial 49 cases and discuss 6 factors important to the successful establishment of an endovascular surgical service: education, teamwork, strict selection of patients, use of a single stent-graft manufacturer, industry support and endovascular preceptorship. Our experience may be used as a model by other institutions in Canada.     

The heparin-induced thrombocytopenia and thrombosis syndrome: Treatment with intraarterial urokinase and systemic platelet aggregation inhibitors

We report a case of the heparin-induced thrombocy-topenia and thrombosis syndrome presenting with acute ischemia of a lower limb. The patient was successfully treated by withdrawal of heparin products, intraarterial urokinase, and platelet anti-aggregation therapy consisting of Dextran and aspirin.     

Clone-based systematic haplotyping (CSH): a procedure for physical haplotyping of whole genomes

We present a novel methodology to determine the phase of single-nucleotide polymorphisms (SNPs) on a chromosome, which we term clone-based systematic haplotyping (CSH). The CSH procedure is based on separating the allelic chromosomes of a diploid genome by fosmid/cosmid cloning, and subsequent SNP typing of 96 clone pools, each representing approximately 10% of the genome. The pools are screened by PCR for the sequence of interest, followed by SNP typing on the PCR products using the GOOD assay. We demonstrate that by CSH, the haplotype of SNPs separated by more than 50 kilobases can definitely be assigned. We propose this method as being suitable for constructing maps of ancestral haplotypes, analysis of complex diseases, and for diagnosis of rare defects in which the molecular haplotype is crucial. In addition, by amplifying the initial DNA by many orders of magnitude, the original DNA resource is effectively immortalized, enabling the haplotyping of hundreds of thousands of SNPs per individual.     

Role of radionuclide perfusion study in cold solitary thyroid nodule for diagnosis of malignancy: a complimentary diagnostic modality to fine needle aspiration cytology

One hundred and forty eight subjects with euthyroid solitary thyroid nodules (STN) were taken up for radionuclide perfusion study. They were found to have a cold STN on 99mTc thyroid static scan. All had fine needle aspiration cytology (FNAC), and except for subjects with chronic lymphocytic thyroiditis, were subjected to surgery for tissue diagnosis by histopathology. The diagnostic findings in these patients of solitary thyroid nodules were correlated with the histopathology. Radionuclide perfusion study is considered useful to differentiate benign from malignant cold thyroid solitary nodules with high degree of sensitivity (95%) and specificity (87.9%).     

Receiver Operating Characteristic (ROC) to Determine Cut-Off Points of Biomarkers in Lung Cancer Patients

The role of biomarkers in disease prognosis continues to be an important investigation in many cancer studies. In order for these biomarkers to have practical application in clinical decision making regarding patient treatment and follow-up, it is common to dichotomize patients into those with low vs. high expression levels. In this study, receiver operating characteristic (ROC) curves, area under the curve (AUC) of the ROC, sensitivity, specificity, as well as likelihood ratios were calculated to determine levels of growth factor biomarkers that best differentiate lung cancer cases versus control subjects. Selected cut-off points for p185^erbB-2 and EGFR membrane appear to have good discriminating power to differentiate control tissues versus uninvolved tissues from patients with lung cancer (AUC = 89% and 90%, respectively); while AUC increased to at least 90% for selected cut-off points for p185^erbB-2 membrane, EGFR membrane, and FASE when comparing between control versus carcinoma tissues from lung cancer cases. Using data from control subjects compared to patients with lung cancer, we presented a simple and intuitive approach to determine dichotomized levels of biomarkers and validated the value of these biomarkers as surrogate endpoints for cancer outcome.     

The middle cranial fossa approach: an anatomical study

Hearing preservation surgery has become an option for an increasing number of patients with vestibular schwannomas due to diagnosis at an earlier stage. The middle cranial fossa approach represents one such surgical approach for resection of vestibular schwannomas with hearing preservation. We have undertaken an anatomical study of the middle cranial fossa approach to the internal auditory meatus using 20 fresh temporal bones. By simulating the surgical approach it was possible to analyze critically two of the main recognized subapproaches to the internal acoustic meatus. The results confirmed that the angle subtended by the facial nerve and "blue-lined" semicircular canal was much less than 60 degrees but equally important was the degree of individual variability. Furthermore the roof of the geniculate fossa was not infrequently dehiscent. The distance measured from the inner table of the craniotomy to the superior semicircular canal was on average 22 mm, similar to previous reports and utilized by some in their approach in this challenging surgery. From this anatomical study it appears that safe dissection of this area is facilitated by observing the more acute angle between the facial nerve and superior semicircular canal and by taking advantage of the relationship between the inner table and important landmarks.