Vascular Centerline Extraction in 3D MR Angiograms for Phase Contrast MRI Blood Flow Measurement

The accuracy of 2D phase contrast (PC) magnetic resonance angiography (MRA) depends on the alignment between the vessels and the imaging plane. PC MRA imaging of blood flow is challenging when the flow in several vessels is to be evaluated with one acquisition. For this purpose, semi-automatic determination of the plane most perpendicular to several vessels is proposed based on centerlines extracted from 3D MRA. Arterial centerlines are extracted from 3D MRA based on iterative estimation-prediction, multi-scale analysis of image moments, and a second-order shape model. The optimal plane is determined by minimizing misalignment between its normal vector and the centerlines’ tangent vectors. The method was evaluated on a phantom and on 35 patients, by seeking the optimal plane for cerebral blood flow quantification simultaneously in internal carotids and vertebral arteries. In the phantom, difference of orientation and of height between known and calculated planes was 1.2° and 2.5 mm, respectively. In the patients, all but one centerline were correctly extracted and the misalignment of the plane was within 12° per artery. Semi-automatic centerline extraction simplifies and automates determination of the plane orthogonal to one vessel, thereby permitting automatic simultaneous minimization of the misalignment with several vessels in PC MRA.     

Antioxidative and anti-inflammatory effects of repaglinide in plasma of diabetic animals.

Oxidative stress, defined as an imbalance between the production of reactive oxygen species (ROS) and antioxidant defense, is considered to be an important pathogenic factor in diabetes mellitus and its complications. In diabetic state, ROS might also be implicated in promoting a state of systemic inflammation. Recently, it was demonstrated that antioxidant therapy could be used to stop the initiation and propagation of this inflammatory response. Repaglinide is a new oral antidiabetic agent with a possible antioxidant activity. Therefore, in the present study, a possible therapeutic value of repaglinide in ameliorating the oxidative and inflammatory processes was tested in diabetic animals. In the study, the levels of total antioxidant status (TAS), ascorbic acid (AA), protein carbonyl groups (PCG) and interleukin-6 (IL-6) were determined in plasma of diabetic rabbits after 4 and 8 weeks of repaglinide treatment (1mg daily). Ex vivo analysis revealed that there were significant differences in these markers between hyperglycemic and control animals (P<0.05). Some of these parameters were ameliorated by repaglinide treatment. In diabetic rabbits treated with repaglinide, protein oxidation was diminished by 17.8% after 8 weeks of experiment. The level of AA in plasma of diabetic treated animals was higher than in non-treated diabetic groups (by 9.4 and 22.6% after 4 and 8 weeks, respectively). In diabetic treated animals, the TAS level was also significantly increased (by 23.6 and 16.7%). However, in diabetic rabbits, repaglinide did not affect the concentration of IL-6.     

Mapping of functional regions of Clostridium perfringens type A enterotoxin.

Studies were conducted to allow construction of an initial map of the structure-versus-function relationship of the Clostridium perfringens type A enterotoxin (CPE). Removal of the N-terminal 25 amino acids of CPE increased the primary cytotoxic effect of CPE but did not affect binding. CPE sequences required for at least four epitopes were also identified.     

Liver blood flow after major hepatic resection

The factors involved in liver regeneration are poorly understood, but it has been suggested that blood flow plays a role. This paper documents the changes in liver blood flow (LBF) that occur after major hepatic resection. Eight patients, ranging in age from 37 to 76 years, underwent liver resection. Liver blood flow was measured preoperatively and on days 1, 4 and 7 postoperatively by low-dose galactose clearance. There was a significant (p less than 0.01) fall in LBF on day 1 compared with the baseline value, followed by a significant (p less than 0.01) rise from the baseline value by day 4. By day 7, LBF had returned to baseline levels and was significantly (p less than 0.01) lower than on day 4. These changes in LBF may be related to the stimulus for liver regeneration and increased functional demands during the early regenerative phase.     

Aggressive giant fibroepithelial lesion with unusual vascular stroma--a case report.

The stroma of fibroadenoma and phyllodes tumor usually consists of fibroblastic proliferation. Rarely the stroma contains bundles of smooth muscle. Pseudoangiomatous hyperplasia of the mammary stroma has been described in fibroadenomas. However, true benign vascular stroma has not been reported. We report a case of a 34-year-old Chinese woman who presented with a large mass occupying the entire left breast. Left mastectomy was performed and showed a large, well-circumscribed, lobulated, rubbery-firm tumor measuring 13 x 10 x 6 cm. Microscopic examination revealed a fibroepithelial tumor formed by an organoid pattern of ductal structures with a very striking stromal appearance composed of extensive vascular proliferation and that demonstrated strong immunoreactivity for CD31, CD34, and Factor VIII. Ultrastructural examination revealed intercellular junctions, basal lamina, pinocytotic vesicles, and Weibel-Palade bodies in the cells lining the vascular spaces, confirming their endothelial nature. These findings rule out the diagnosis of pseudoangiomatous hyperplasia. The patient developed local recurrence a year later, and the resection showed malignant phyllodes tumor with ductal carcinoma in situ.The extensive vascular stroma noted in the primary tumor may have played a role in the malignant transformation of the epithelial and stromal components in this tumor.     

Lymphoma presenting as a salivary gland mass

A retrospective review of 36 cases of lymphoma presenting as a salivary gland mass was conducted over a 34-year period. A significant increase in the occurrence of lymphoma was noted in proportion to other salivary gland tumors (P less than 0.01, chi 2 analysis: 1954-1972, 11 of 714 (1.5%); 1973-1979, 9 of 201 (4.5%); 1980-1987, 16 of 265 (6.0%). The mean age was 61 years, sex distribution was equal, and 75% occurred in the parotid. Only 42% presented with signs or symptoms other than a painless mass. Glandular excision was done in early stages of the disease while biopsy was done at later stages. Frozen section analysis was accurate in all but one case and was useful in determining if biopsy were adequate. All patients were definitively treated with chemotherapy and/or radiotherapy. Several instructive points are apparent. Any patient presenting with an isolated salivary gland mass can have a lymphoma. There has, in fact, been a significantly increasing proportion of salivary gland lymphoma among the various salivary gland tumors in our patient population. In contrast to other salivary gland tumors, surgery is reserved for diagnosis and not for treatment. A lymph node biopsy may be sufficient to establish a diagnosis, in which case, glandular excision is unnecessary. Most of the patients presented with an asymptomatic isolated salivary gland mass. The presence of adjacent adenopathy, a rubbery feel to the mass, and the intraoperative appearance were the most suggestive signs of lymphoma. Frozen section analysis is helpful in determining the appropriate extent of surgery and is recommended.