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Biomedical subjects

Geoffrey Gardiner

Publications and source records attributed to Geoffrey Gardiner.

6 recordsLinked to original sources
PubMed2005

Endoscopic Doppler optical coherence tomography in the human GI tract: initial experience.

BACKGROUND: Expanding the current endoscopic optical coherence tomography (OCT) system with Doppler capability may augment this novel high-resolution cross-sectional imaging technique with functional blood flow information. The aim of this feasibility study was to assess the clinical feasibility of an endoscopic Doppler OCT (EDOCT) system in the human GI tract. METHODS: During routine endoscopy, 22 patients were imaged by using a prototype EDOCT system, which provided color-Doppler and velocity-variance images of mucosal and submucosal blood flow at one frame per second, simultaneously with high-spatial-resolution (10-25 mum) images of tissue microstructure. The images were acquired from normal GI tract and pathologic tissues. OBSERVATIONS: Subsurface microstructure and microcirculation images of normal and pathologic GI tissues, including Barrett's esophagus, esophageal varices, portal hypertensive gastropathy, gastric antral vascular ectasia, gastric lymphoma, and duodenal adenocarcinoma, were obtained from 72 individual sites in vivo. Differences in vessel diameter, distribution, density, and blood-flow velocity were observed among the GI tissue pathologies imaged. CONCLUSIONS: To our knowledge, this is the first study to demonstrate the feasibility of EDOCT imaging in the human GI tract during routine endoscopy procedures. EDOCT may detect the different microcirculation patterns exhibited by normal and diseased tissues, which may be useful for diagnostic imaging and treatment monitoring.

Adult↗
PubMed2003

In vivo Doppler optical coherence tomography of mucocutaneous telangiectases in hereditary hemorrhagic telangiectasia.

BACKGROUND: Hereditary hemorrhagic telangiectasia is characterized by mucocutaneous telangiectases and visceral arteriovenous malformations. Knowledge is limited concerning the development hemodynamics of mucocutaneous telangiectases. Doppler optical coherence tomography can demonstrate microvascular blood flow at flow rates as low as 20 microm/second, which is up to approximately 100 times more sensitive than Doppler US. The aims of this study were to collect in vivo Doppler optical coherence tomography images of mucocutaneous telangiectases and normal surrounding mucosa and skin, and to gain experience for an in vivo GI endoscopic study. It was hypothesized that visibly normal areas may have occult telangiectases and that mucocutaneous telangiectases that have bled may have a higher rate of blood flow than mucocutaneous telangiectases with no history of bleeding. METHODS: Twelve patients with hereditary hemorrhagic telangiectasia and mucocutaneous telangiectases were studied. Two to 3 visible mucocutaneous telangiectases on the digits, lips, and tongue were imaged with Doppler optical coherence tomography, along with visually normal surrounding areas at each site. The Doppler optical coherence tomography images were obtained in 0.5 second by using 1310 nm light. RESULTS: A total of 67 mucocutaneous telangiectases from the 12 patients were imaged (38 digit, 16 lip, 13 tongue). Blood flow was demonstrated within every mucocutaneous telangiectasis imaged. Doppler optical coherence tomography did not identify any abnormal vasculature within visually normal areas. Mucocutaneous telangiectases with a history of bleeding (n = 18) were situated closer to the surface, compared with mucocutaneous telangiectases with no bleeding history (n = 49), but there was no difference in the Doppler flow appearance. CONCLUSIONS: Visually normal areas in patients with hereditary hemorrhagic telangiectasia did not appear to have abnormal vasculature. Mucocutaneous telangiectases with a history of bleeding were more superficial but were otherwise similar to mucocutaneous telangiectases with no bleeding history.

Adult↗
PubMed2003

Ramipril-associated hepatotoxicity.

CONTEXT: Angiotensin-converting enzyme inhibitors are prescribed for many cardiovascular and renal diseases. Adverse hepatic events, especially cholestasis, have rarely been reported with captopril, enalapril, lisinopril, and fosinopril. To date, hepatic injury associated with ramipril has not been reported. OBJECTIVE: To describe 3 patients who developed hepatitis, with or without jaundice, after receiving ramipril. DESIGN: Medical records and liver biopsies of the 3 patients were reviewed. Clinical, laboratory, and histologic findings were compared with findings in other cases of angiotensin-converting enzyme inhibitor-induced liver injury reported in the literature. RESULTS: The 3 patients were middle-aged men. In 2 patients, jaundice appeared 4 and 8 weeks after starting ramipril. Bilirubin levels peaked at 15.5 and 5 mg/dL, and alkaline phosphatase values peaked at 957 and 507 U/L. Aminotransferase levels were mildly elevated. Endoscopic retrograde cholangiopancreatography and ultrasonography showed no bile duct obstruction. Liver biopsies from the jaundiced patients were similar, with cholestasis, duct necrosis, and extravasation of bile, ductular proliferation, and portal inflammation. Cholestasis improved in 1 patient 6 weeks after stopping ramipril and was prolonged for 14 months in the other, in whom biliary cirrhosis was present on biopsy. The third patient developed hepatitis without jaundice 3 weeks after starting ramipril; symptoms resolved after stopping the drug. Ramipril-associated liver injury is similar to that seen with other angiotensin-converting enzyme inhibitors, but liver biopsy findings of duct necrosis and extravasation of bile have not been reported previously. CONCLUSION: Prolonged cholestatic hepatitis and biliary cirrhosis may result from the use of ramipril. Monitoring of liver enzymes is advisable for patients starting on ramipril.

Angiotensin-Converting Enzyme Inhibitors↗
PubMedDate not supplied

Follicular carcinoma of the thyroid with aggressive metastatic behavior in a pregnant woman: report of a case and review of the literature.

Distant metastases as initial presentation of follicular carcinoma of the thyroid is rare, especially in young patients. We report the clinical and pathological features of a 33-year old pregnant patient with follicular carcinoma of the thyroid who presented with widespread bone and lung metastases at the time of diagnosis. the resected tumor had a focal insular component that showed extensive vascular invasion spreading beyond the thyroid capsule, and was associated with widespread bone and lung metastases. Despite its aggressive behavior, the tumor had low mitotic activity and Ki-67 nuclear labeling index. tumor cells showed high microvascular density and down-regulation of E-cadherin, a calcium-dependent trans-membrane epithelial protein molecule known to promote intercellular adhesion. We suggest that architectural differentiation of the tumor and cell proliferation rate are not reliable markers of metastatic behavior in this particular thyroid neoplasm. Microvascular density and down-regulation of E-cadherin expression in the tumor should be included among histologic hallmarks of metastatic potential. the role of pregnancy in the aggressive behavior of this tumor is discussed along with a literature review.

Adenocarcinoma, Follicular↗