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Biomedical subjects

Theresa L Nicol

Publications and source records attributed to Theresa L Nicol.

8 recordsLinked to original sources
PubMed2006

Percutaneous bladder cryoablation in porcine model.

PURPOSE: To demonstrate the morphologic changes of full-thickness bladder cryoablation utilizing contemporary percutaneous technology. MATERIALS AND METHODS: Cryoablation of the bladder wall was conducted in 24 pigs. The bladders were exposed laparoscopically and inspected cystoscopically. The animals underwent either extravesical (serosal) or transvesical (mucosal) approaches for the creation of the cryoablation lesion. Single or double freeze/thaw cycles were applied, and no bladder drainage was used. The bladder was evaluated for perforation, and histologic examination was undertaken to assess the extent of acute, subacute (2 weeks), or chronic (1 month) lesions. RESULTS: Cryoablation reliably produced a controlled transmural area of necrosis (both serosa and mucosa) by both techniques. The size and extent of the lesion were directly proportional to the duration of freezing and the type of cryoprobe used. The pathology report confirmed the full-thickness coagulative necrosis of muscle. Bladder perforation was not detected clinically or at autopsy. CONCLUSION: Cryoablation produces reliable zones of tissue destruction without bladder perforation. These preliminary data show the safety and feasibility for trials in the treatment of bladder tumors by laparoscopic, cystoscopic, or image-guided techniques.

Animals↗
PubMed2006

Prophylactic gelatin sponge tract injection to prevent bleeding after percutaneous renal cryoablation in a swine model.

PURPOSE: Achievement of hemostasis can be a challenge during percutaneous renal cryoablation (PRC). This study describes the use of a porcine model to test the ability of gelatin sponge injection into the tract to limit bleeding at the site of cryoprobe puncture. MATERIALS AND METHODS: A total of nine swine (18 kidneys) underwent bilateral ultrasound-guided PRC with double freeze/thaw cycle protocol with use of a 2.4-mm cryoprobe. The cryoablation location and protocol were applied identically to both kidneys in each pig; however, only one side received gelatin sponge injection after cryoablation through a coaxial sheath (3 mm). After removal of the sheath, a midline laparotomy incision was performed and sponges were placed around the kidneys. Blood loss was measured by calculating the change in weight of the sponges after 30 minutes of absorption time. Acute blood loss was compared between the two groups. The kidneys treated with gelatin sponge were removed and grossly and histologically examined to identify the gelatin sponge at the puncture cryolesion. RESULTS: The use of gelatin sponge resulted in significantly less blood loss (mean, 8.24 mg +/- 4.68) compared with the control kidneys (mean, 20.24 mg +/- 8.14; P = .001). Gross and histopathologic results confirmed that the gelatin sponge was in the cryoablation puncture sites. Mean diameters of cryoablation ice balls on the gelatin sponge and control sides were 3.9 cm +/- 0.2 and 3.8 cm +/- 0.4, respectively. The lesions were not significantly different between sides. CONCLUSION: Percutaneous tract injection of gelatin sponge appears promising as a method to decrease acute blood loss from PRC.

Angioplasty, Balloon↗
PubMed2005

Metastatic breast carcinoma involving the thyroid gland diagnosed by fine-needle aspiration: a case report.

Secondary involvement of the thyroid gland from a remote primary malignancy is uncommon. The distinction of metastatic carcinoma (MC) or sarcoma from a primary thyroid malignancy is important because the treatment is different. We discuss a case of a 64-yr-old female with a history of breast carcinoma, who presented with pain and swelling in her neck 5 yrs after being diagnosed with breast cancer. She had undergone mastectomy with subsequent chemotherapy and radiation for infiltrating mammary carcinoma. During the 5-yr interval, she had been free of clinically evident metastatic disease. Subsequent work-up revealed two distinct nodules in the left lobe of her thyroid gland as well as a subcutaneous mass in her right shoulder. A fine-needle aspiration (FNA) of the larger thyroid nodule showed malignant epithelial cells with features consistent with breast carcinoma in a background of benign thyroid epithelial cells and colloid. The case was signed out as metastatic breast carcinoma. Subsequent FNA and biopsy of her right shoulder lesion also revealed metastatic breast carcinoma with similar morphology to the material in the thyroid FNA.

Biopsy, Fine-Needle↗
PubMed2004

Molecular profiling and classification of sporadic renal cell carcinoma by quantitative methylation analysis.

PURPOSE: Preoperative histologic classification of solid renal masses remains limited with current technology. We determine the utility of molecular profiling based on quantitative methylation analysis for characterization of sporadic renal cell carcinoma. EXPERIMENTAL DESIGN: Primary renal cell carcinomas representing three different histologic subtypes were obtained from a total of 38 patients who underwent radical nephrectomy for suspected malignant disease. Genomic DNA was isolated from tumors and was subjected to sodium bisulfite modification. The normalized index of methylation (NIM) for each sample was determined by quantitative real-time methylation-specific PCR at 17 different gene promoters. Hierarchical cluster analysis was performed by using an unsupervised neural network with binary tree topology. RESULTS: The majority of gene promoters that were analyzed in this study demonstrated very low levels of methylation (NIM <1.0). The RASSF1A gene promoter, however, was methylated in 30 of 38 (79%) cases. The frequency of RASSF1A methylation in papillary, clear-cell, and oncocytoma subtypes was 100, 90, and 25%, respectively. The highest levels of RASSF1A methylation were observed in the papillary (mean NIM = 78.9) and clear-cell (mean NIM = 13.4) subtypes. The vast majority of oncocytomas were completely unmethylated, and none demonstrated >1% methylation (mean NIM = 0.11). Hierarchical cluster analysis based on quantitative methylation levels resulted in stratification of sporadic renal cell carcinomas into their discrete histologic subtypes. CONCLUSIONS: Classification of sporadic renal cell carcinomas into histologic subtypes can be accomplished via multigene quantitative methylation profiling. Validation of this approach and selection of appropriate methylation markers may ultimately lead to use of this technology in the preoperative assessment of suspicious renal masses.

Aged↗
PubMed2003

Histologic evolution of high-intensity focused ultrasound in rabbit muscle.

RATIONALE AND OBJECTIVES: The purpose of this study was to examine the histologic evolution over time of rabbit skeletal muscle thermally ablated with high-intensity focused ultrasound. The objectives included determining the extent and focality of damage created by this noninvasive, transcutaneous ablative technology. METHODS: Transcutaneous, thermal ablation with an external focused ultrasound transducer was applied to the paraspinous muscles of 19 rabbits. At varying times, up to 100 days after therapy, single sonications were examined histologically. RESULTS: Initially, only subtle staining changes were identified within lesions. In the chronic phase (day 51-100), the muscle was replaced or infiltrated by variable amounts of scar and fat similar to degenerative muscle disorders. Histologic changes were limited to the tissue within the intensity focus of the transducer and were not seen in intervening tissues. DISCUSSION: The current study took a systematic approach to study the long term, in vivo histologic effects of single HIFU lesions in a nonregenerative tissue. This experience in muscle tissue will provide a basis for understanding ultrasound effects for clinical applications such as treatment of uterine fibroids, cardiac tissue, and sarcomas.

Animals↗