Rapid radiotracer washout from the heart: effect on image quality in SPECT performed with a single-headed gamma camera system.

Technetium-99m-teboroxime demonstrates high extraction and rapid washout from the myocardium. To evaluate the feasibility of performing SPECT with this agent using a single-headed gamma camera system, a series of phantom studies were performed that simulated varying degrees of washout from normal and "ischemic" regions of the myocardium. In the absence of ischemic regions, short axis profiles were relatively unaffected by washout of less than 50% of activity over the duration of a SPECT acquisition. However, significant corruption of the SPECT data was observed when large (greater than a factor of 2) differences existed in the washout of activity from normal and "ischemic" myocardium. This corruption was observed with 30%-40% washout of activity from normal regions of the heart. Based on published washout rates, these results indicate that clinical studies with 99mTc-teboroxime may need to be completed within 2-4 min to order to prevent degradation of image quality due to differential washout effects.     

Cardiac cycle extraction from projection data using static signal suppression.

As an extension of the projection-data-based cardiac cycle extraction that we developed previously (W. S. Kim, K. J. Jung, K. D. Lee, J. B. Ra, and Z. H. Cho, "Proceedings, Seventh Annual Meeting of the Society of Magnetic Resonance in Medicine, 1988," p. 958; W. S. Kim, C. W. Mun, D. J. Kim, and Z. H. Cho, Magn. Reson. Med. 13, 25, 1990), a new technique with which one can extract the cardiac cycle by flow-based projection data measurements is described. Because the method uses flow-dependent projection data, it is possible to obtain the cardiac cycle even from regions such as the head, which has virtually no geometrically varying parts, unlike the cardiac region. The signal-to-noise of this flow (such as blood and CSF) based projection data acquisition is further enhanced by the use of the static sample signal suppression technique developed for angiography (J. H. Kim and Z. H. Cho, Magn. Reson. Med. 14, 554, 1990).     

Morphological changes of retinal ganglion cells regenerating axons along peripheral nerve grafts: a Lucifer Yellow and silver staining study

The morphology of the retinal ganglion cells (RGCs) with their axons regenerating along a peripheral nerve graft at different post-grafting periods was studied by the intracellular injection of Lucifer yellow (LY) and silver staining methods. Several morphological features which were observed on developing RGCs, but not mature RGCs, have also been observed in the regenerating RGCs studied by the intracellular injection of LY. These morphological features observed on the regenerating RGCs included intraretinal axonal branches and collaterals, spine-like processes on the dendrites and soma, and short processes on the soma. These results suggest that damaged mammalian RGCs may be able to recapitulate certain cellular events which occur during normal development provided the regenerating cells are given the proper stimulus and a favorable environment for regrowth. From the results of both LY injection and silver staining experiments, it was found that the dendrites of the regenerating RGCs were, in general, much simpler than that of control Type I RGCs. However, regenerating RGCs with different degree of dendritic complexity could be observed in all post-grafting periods studied, and the dendritic complexity seems to decrease continuously with the increase in the post-grafting time. These results suggest that the ability to regenerate an axon is not closely related to dendritic responses and the peripheral nerve does not seem to be able to prevent the deterioration and retraction of the dendrites.     

Growth of vascularized composite mandibular allografts in young rabbits

Forty-one hemimandible allografts were transplanted in young rabbits immunosuppressed with cyclosporine. The majority of the grafts demonstrated normal wound healing, and growth of hair, bone, and teeth. The mandibular body and the premolars showed significant growth in length. The allografted mandibles functioned sufficiently that the rabbits took oral nourishment soon after surgery. Long-term survival was limited by a toxic "wasting syndrome" specific for rabbits under treatment with cyclosporine.     

Classification of metaphyseal change with magnetic resonance imaging in Legg-Calvé-Perthes disease

Seventy-eight patients (85 affected hips and 71 unaffected hips) with Legg-Calvé-Perthes disease were included in this study to evaluate the metaphyseal change in radiographs and magnetic resonance imaging (MRI) and to define the type of the metaphyseal cyst according to presence or absence of the epiphyseal involvement. The content of the metaphyseal cyst was evaluated by using T1,T2, proton, and gadolinium-enhanced T1-weighted MRI scans. Among 85 hips, there were no changes in 32 hips, marrow edema in 13 hips, false cyst with epiphyseal involvement in 28 hips, and true cyst without epiphyseal involvement in 12 hips. Granulation tissue was found in the false cysts and water-rich fibrotic tissue was found in the true cysts based on the MRI scans. The metaphyseal change in MRI scans was shown in 71% of groups 3 and 4 and in 35% of groups 1 and 2 according to the Catterall classification, and 52% of group A, 56% of group B, and 86% of group C according to the Herring classification. Of the 30 hips at the avascular stage, 33% showed metaphyseal cyst in MRI scans. Of the 53 hips at the fragmentation stage, 60% showed the metaphyseal cyst.     

Down-Regulation of Osteoblastic Cell Differentiation by Epidermal Growth Factor Receptor

The role of epidermal growth factor receptors (EGF-R) in osteogenic cell differentiation was investigated using preosteoblastic MC3T3-E1 (MC3T3) cells and osteoblast-like ROS 17/2.8 (ROS) cells. When cultured in the presence of β-glycerophosphate (GP) and ascorbic acid (AA), MC3T3 cells underwent spontaneous differentiation into osteoblasts which was confirmed as they expressed osteoblast markers such as alkaline phosphatase (ALP), bone sialoprotein (BSP) and osteocalcin (OC). Interestingly, the number of EGF-binding sites decreased during their differentiation into osteoblasts, and the osteogenic protein-1 (OP-1) treatment, which accelerated their differentiation, lowered the number of EGF-binding sites even further. On the other hand, ROS cells with high expression levels of osteoblast markers and no EGF-R, after being transfected with human EGF-R cDNA (EROS cells), expressed numerous EGF-binding sites as well as EGF-R mRNA and protein; in the process, they ceased to express osteoblast markers, indicating their dedifferentiation into osteoprogenitor cells. Both MC3T3 and EROS cells showed increased cell growth in response to EGF, whereas ROS cells did not. These results imply that the EGF/EGF-R system in osteogenic cells has a crucial function in osteoblast phenotype suppression and osteogenic cell proliferation.     

Synchronous coexpression of epidermal growth factor receptor and cyclooxygenase-2 in carcinomas of the uterine cervix: a potential predictor of poor survival.

PURPOSE: To evaluate the potential of the new prognostic information gained by analyzing the coexpression of epidermal growth factor receptor (EGFR) and cyclooxygenase-2 (COX-2) in cervical cancer patients. EXPERIMENTAL DESIGN: Sixty-eight patients with International Federation of Gynecology and Obstetrics stage IIB squamous cell carcinoma of the uterine cervix, who underwent concurrent chemoradiotherapy between 1993 and 1996, were divided into the following four groups according to their immunoreactivities for EGFR and COX-2 in paraffin-embedded sections: (a). the EGFR-negative/COX-2-negative group (n = 11); (b). the EGFR-negative/COX-2-positive group (n = 8); (c). the EGFR-positive/COX-2-negative group (n = 27); and (d). the EGFR-positive/COX-2-positive group (n = 22). The clinical features, patterns of treatment failure, and survival data in the four groups were compared. RESULTS: Positive immunoreactivity for EGFR and COX-2 was observed in 49 of 68 (72%) and 19 of 68 (28%), respectively. However, no strong correlation was found between the levels of EGFR and COX-2 immunopositivity (R(2) = 0.05, P = 0.07). Patients in the EGFR-positive/COX-2-positive group had a higher likelihood of locoregional recurrence than those in the other three groups (P = 0.02). Of the patients in the four groups, patients positive for both oncoproteins were found to have the worst prognosis with an overall 5-year disease-free survival rate of 55% compared with 91% for the EGFR-negative/COX-2-negative patients, 88% for the EGFR-negative/COX-2-positive patients, and 69% for the EGFR-positive/COX-2-negative patients (P = 0.05, log-rank test). In addition, the synchronous coexpression of the EGFR and COX-2 oncoproteins was found to be an independent prognostic factor by univariate and multivariate analyses (relative risk = 4.0, P = 0.03). CONCLUSIONS: Given these observations, we conclude that the coexpression of EGFR and COX-2 immunoreactivity may be used as a potent molecular risk factor for predicting the poor survival of patients with the International Federation of Gynecology and Obstetrics stage IIB squamous cell carcinoma of the uterine cervix.     

A phase II trial of capecitabine in previously untreated patients with advanced and/or metastatic gastric cancer.

BACKGROUND: Capecitabine (Xeloda) is a novel, oral, selectively tumor-activated fluoropyrimidine with proven activity in the treatment of advanced colorectal cancer. This trial was conducted to evaluate the efficacy, safety and feasibility of capecitabine in previously untreated patients with advanced and/or metastatic gastric cancer, with a view to replacing 5-fluorouracil (5-FU) in such patients. PATIENTS AND METHODS: Forty-four patients received capecitabine 1250 mg/m2 twice daily (2500 mg/m2/day) for 14 days followed by 7 days of rest, for up to six cycles. RESULTS: Capecitabine produced an objective response rate of 34% (all partial responses) and stable disease in 14 patients (30%). The median time to disease progression (TTP) was 3.2 months [95% confidence interval (CI) 2.7-6.4 months] and median overall survival was 9.5 months (95% CI 6.9-13.2 months). Hand-foot syndrome (HFS), nausea, anorexia, diarrhea and vomiting were the most common adverse events. While HFS was the most frequent grade 3/4 toxicity (National Cancer Institute Common Toxicity Criteria), only 9% of patients experienced grade 3 HFS. Severe myelosuppression was not reported during the study. CONCLUSIONS: Capecitabine monotherapy is active and well tolerated as first-line therapy in patients with advanced/metastatic gastric cancer. Larger comparative trials investigating capecitabine-based combination regimens in patients with advanced gastric cancer are warranted.     

Replantation of avulsed scalps and secondary aesthetic correction

Five patients with avulsed scalps were treated with replantation between 1992 and 1998. All patients were women age 20 to 36 years. The percentage of the avulsed scalp ranged from 50% to 100% of the whole scalp. The vessels chosen for anastomosis were the superficial temporal artery, occipital artery, and superficial temporal vein. A vein graft harvested from the cephalic vein of the forearm was performed on the venous and arterial sides in 1 patient. Two patients experienced complete survival of the replanted scalp. Three patients showed 40%, 50%, and 80% survival areas, with the remaining defects resurfaced as split-thickness skin grafts. Six months later, the scar areas in the last 3 patients were reconstructed with an expansion of the normal or replanted scalp. The follow-up period ranged from 1 to 7 years. In 4 patients a partial return of sensation in the replanted scalp and motor function of the frontalis muscle were observed. All patients were satisfied with the aesthetic results of their surgery.