Echocardiographic evidence of left ventricular hypertrophy in obese dogs.

BACKGROUND: Cardiomyopathy of obesity occurs in humans, but the gross and cellular myocardial response to obesity in dogs is not well defined. OBJECTIVES: To characterize in vivo myocardial morphology and function in normotensive obese dogs, and quantitate collagen, triglyceride and myocyte cross-sectional area (CSA) in postmortem tissues from obese dogs. ANIMALS: Echocardiographic-Doppler measurements of normotensive obese dogs (n = 19) without historical or physical examination evidence of disease, and lean healthy dogs (n = 19) matched for age and ideal weight. Postmortem data were obtained from a separate population of 4 obese and 12 lean dogs without evidence of cardiac disease. METHODS: A prospective, observational study of myocardial morphology and function was conducted by echocardiographic-Doppler measurement. Left ventricular (LV) tissue was collected for quantitation of triglyceride, collagen, and myocyte CSA. RESULTS: Compared with lean control dogs, obese dogs had increased systolic blood pressure (obese 153 ± 19 mm Hg; lean 133 ± 20 mm Hg; P = .003), and increased LV free wall thickness at end-diastole (obese 9.9 ± 1.8 mm, lean 8.7 ± 1.5 mm; P = .03) and end-systole (obese 15.2 ± 2.3 mm, lean 12.9 ± 2.3 mm; P = .004). Isovolumic relaxation time was prolonged in 7/19 (37%) of obese dogs, compared with normal ranges. Myocardial triglyceride and collagen content and myocyte CSA were similar between groups. CONCLUSIONS AND CLINICAL IMPORTANCE: As in humans, LV hypertrophy and diastolic dysfunction can be an early myocardial change in some obese dogs.

Assessment of vessel wall thickness in carotid atherosclerosis using spiral CT angiography.

OBJECTIVES: the purpose of this study was to evaluate the amount of vessel wall thickening in the internal and common carotid arteries in patients undergoing spiral CT angiography for the investigation of significant atherosclerotic disease. MATERIALS AND METHODS: forty-five carotid systems in patients with a 70% or greater stenosis (according to carotid duplex) were imaged with CT spiral angiography using a standardised protocol. The vessel wall thickness of the distal common and mid internal carotid artery was measured using axial CT sections. RESULTS: vessel wall thickness was greater and more variable within the common carotid artery than within the internal carotid artery. The mean proportion of total vessel diameter constituted by vessel wall thickness was significantly greater in the common carotid artery as compared to the internal carotid artery: 28+/-12% (SD) vs 15+/-6%, respectively (p < 0.001). CONCLUSIONS: significant and extended wall thickening is commonly present in the internal and common carotid arteries of patients with atherosclerotic disease, but the internal carotid artery is significantly less affected than the common carotid artery. These observations question the validity of using the common carotid artery as a reference vessel for angiographic stenosis measurements.

Evaluation of cross-sectional luminal morphology in carotid atherosclerotic disease by use of spiral CT angiography.

BACKGROUND AND PURPOSE: This study sought to determine the frequency of noncircular lumens in patients with significant carotid atherosclerotic disease and to evaluate the effect of noncircular lumens on stenosis measurement derived from angiographic projections. METHODS: One hundred consecutive patients presenting with an internal carotid artery stenosis of at least 50% were imaged with spiral CT angiography. The transverse morphology of the diseased lumen was assessed on axial images, and the frequency of noncircular lumens was determined. In these cases, maximum intensity projection angiograms were reconstructed in standardized angiographic planes and in a plane selected according to the luminal obliquity, which was chosen to optimize the angiographic representation of the maximal stenosis. North American Symptomatic Carotid Endarterectomy Trial (NASCET) measurements were calculated from the maximum intensity projection images, and differences between values obtained from standard and optimized projections were recorded. RESULTS: Noncircular lumens were observed in 18 of 100 patients and consisted of elliptical and linear transverse profiles. The transverse orientation of the lumen in these cases ranged from +90 degrees to -87 degrees relative to the anteroposterior plane. An increase in the calculated NASCET stenosis was demonstrated when measurements were obtained from angiographic reconstructions obtained in the exact plane of the luminal obliquity compared with standard angiographic projections. As a result, the stenosis severity was upgraded from moderate to severe in 2 patients. CONCLUSIONS: Noncircular transverse luminal profiles are not uncommon and may introduce error into NASCET calculations obtained from standard angiographic projections.

Telomerase activity in malignant and benign renal tumors.

OBJECTIVES: An important characteristic of malignant cells is their unlimited replicative potential, their immortality. In conferring this immortality, the enzyme telomerase is believed to play a crucial role. The detection of telomerase activity provides new knowledge regarding the biologic growth behavior of tumors and offers new diagnostic and therapeutic tools. METHODS: In the present study the sensitive TRAP assay (telomeric repeat amplification protocol) was used to examine 44 malignant renal tumors and 8 benign tumors of the kidney and 52 specimens of normal renal tissue for telomerase activity. RESULTS: Telomerase activity was detected in 63% of tissue samples obtained from histologically confirmed renal cell carcinomas. In cases of renal cell carcinoma restricted to the kidney, telomerase activity was detected in 58%. In cases in which tumor growth has progressed beyond the limits of the organ, telomerase activity was found in 69%. This stage dependence, however, did not reach statistical significance. No correlation to tumor grading was observed. Telomerase activity was found less frequent in chromophobe renal cell carcinomas. Neither the 8 benign renal tumors (4 oncocytomas and 4 angiomyolipomas) nor the specimens of normal kidney showed any evidence of telomerase activity. CONCLUSIONS: The proportion of remarkable slow-growing renal cell carcinomas showing telomerase activity is less than in other malignancies and may correlate with biologic growth behavior. Possible explanations include the presence of an alternative pathway, called ALT (alternative lengthening of telomeres) and an association with the loss or presence of the telomerase suppressor on the short arm of chromosome 3. Prolonged follow-up will be of special interest to determine whether lack of telomerase activity predicts favorable outcome.