Apparent diffusion coefficients of benign and malignant salivary gland tumors. Comparison to histopathological findings

OBJECTIVE

To evaluate the apparent diffusion coefficient (ADC) of benign and malignant salivary gland tumors in comparison to histopathological findings.

MATERIALS AND METHODS

This study included 32 patients with a wide spectrum of major salivary gland tumors (17 benign, 15 malignant). Diffusion-weighted imaging (DWI) and ADC measurements were performed in all patients. The degrees of extracellular components (myxoid and chondroid matrices, microcysts and hyalinization), were histopathologically classified as mild, moderate and conspicuous. Comparisons were made of mean ADC values between benign and malignant tumors, and among tumors showing different degrees of extracellular components.

RESULTS

Mean ADC values were 1.09+/-0.34 x 10(-3) mm(2)/s in malignant salivary gland tumors and 1.40+/-0.43 x 10(-3) mm(2)/s in benign salivary gland tumors. No significant difference in mean ADC values was found between benign and malignant tumors (P>0.05). However, mean ADC values increased with the degree of extracellular components. Mean ADC values were significantly different between mild and moderate degrees (P<0.05) of extracellular components, and between mild and conspicuous degrees (P<0.05), in both benign and malignant tumor groups.

CONCLUSION

In this study, ADC values alone did not allow differentiation between benign and malignant salivary gland tumors. Comparison with histopathological findings suggests a correlation between the amount of extracellular components and mean ADC values in salivary gland tumors.

Technical optimization of four-channel multidetector-row helical computed tomography for depicting arterial stenosis: a phantom study

PURPOSE

To determine the effects of detector configuration, as well as vessel orientation, on the depiction accuracy of arterial stenosis using four-channel multidetector-row helical computed tomography (MDCT) angiography in vitro.

MATERIAL AND METHODS

Five acrylic vessel phantoms (3 mm in diameter with 25 or 50% stenosis, or 5 mm with 25, 50, or 75% stenosis) were scanned with a four-channel MDCT scanner at five vessel orientations (0, 30, 45, 60, and 90 degrees to the z-axis) using 4 x 1.25, 2.5, 3.75, and 5.0-mm detector configurations at beam pitches of 0.75 and 1.5. The percentage of stenosis was calculated by the ratio of the full width at half maximum for stenotic and non-stenotic portions of the phantom, and compared to the actual known values.

RESULTS

A detector configuration of 4 x 1.25 mm provided good reproducibility, as well as high accuracy for assessing vessel stenosis, while a 4 x 2.5-mm or wider detector configuration caused underestimations of stenosis. Although the phantoms perpendicular to the z-axis were underestimated, the errors were kept in clinically acceptable ranges using the 4 x 1.25-mm detector configuration.

CONCLUSION

Four-channel MDCT accurately discerns stenosis for vessel phantoms of 3 or 5 mm in diameter at any orientation when using a detector configuration of 4 x 1.25 mm.

Interaction between peroxisome proliferator-activated receptor gamma and its agonists: docking study of oximes having 5-benzyl-2,4-thiazolidinedione

The molecular modelling of oximes having 5-benzyl-2,4-thiazolidinedione moieties, agonists of the peroxisome proliferator-activated receptor gamma (PPAR gamma), was performed with respect to their structures complexed with the ligand binding domain of PPAR gamma. For each ligand molecule, the 5-benzyl-2,4-thiazolidinedione head group was used as an anchor and the conformation of the rest of the molecule was searched for the most energetically favorable interaction with the receptor by systematic conformation search and manual modelling. Although both tail-up and tail-down configurations, which have been observed in the crystal structure of eicosapentaenoic acid when complexed with PPAR delta, appeared among the lowest energy structures for most of the compounds, potent agonists were found to adopt a configuration similar to that of rosiglitazone when bound to PPAR gamma, according to the crystal structure. The structure-activity relationships were analyzed based on the receptor-ligand interaction. The alkyl group and the aromatic ring of the tail group of the ligands had hydrophobic interactions with the receptor, and these interactions were found to be essential for the strong activity.

Crosstalk between endothelin and nitric oxide in the control of vascular tone

Several lines of evidence indicate that nitric oxide (NO) impairs endothelin (ET) production/action in vitro. Acute pressor responses caused by the blockade of NO formation with arginine analogues in vivo are blunted by selective ET(A) or dual ET(A)/ET(B) receptor blockade whereas blockade of NO formation magnifies ET-induced constriction of various vascular territories. Given that ET receptor blockade has normally limited effects on mean arterial pressure, the reversal of pressor responses caused by the blockade of NO formation with ET receptor blockade most likely reflects a significant crosstalk between NO and ET. Suppression of NO formation also leads to significant increases in ET production caused by agents targeting the endothelium, such as acetylcholine and thrombin. In addition, the inhibitory effect of shear stress on endothelial cells ET production also involves NO as an intermediate.Paradoxically, chronic exposure to organic nitrates which causes nitrate tolerance leads to an augmented vascular ET content. An increased angiotensin II (AII) production is apparently pivotal in this process. This article reviews observations pointing to the importance of NO/ET interactions as a fundamental and common regulatory mechanism shared across species. As a consequence of this crosstalk between NO and ET, experimental strategies designed to assess endothelial NO-dependent activity by the blockade of NO formation may be mitigated by magnified ET-dependent influences.

Involvement of c-Src in carcinoma cell motility and metastasis

Carcinoma cells exhibit dysfunction / dysregulation of cell adhesion systems that correlates with their abilities to migrate, invade, and metastasize. Here we show that the tyrosine kinase c-Src is required for motility and metastasis of two carcinoma cell lines. Adherent KYN-2 cells having a high level of c-Src kinase activity become scattered, extend lamellipodia, and exhibit high motility. Expression of a dominant-negative mutant form of c-Src caused formation of stress fibers and focal adhesions, and markedly reduced motility. HCT15 cells extended lamellipodia and became scattered in response to lysophosphatidic acid stimulation in parallel with transient activation of c-Src, which was inhibited by expression of a dominant-negative mutant form of c-Src or treatment with a specific Src kinase inhibitor. Furthermore, implantation of dominant-negative c-Src transfectants into the peritoneal cavity of SCID mice resulted in reduced peritoneal dissemination compared with control transfectants. These findings indicate that c-Src activation is critically involved in carcinoma cell migration and metastasis.

Inoculation of human interleukin-17 gene-transfected Meth-A fibrosarcoma cells induces T cell-dependent tumor-specific immunity in mice

OBJECTIVE

The biological activities of interleukin-17 (IL-17), a newly cloned cytokine, have not been fully elucidated. The present study was designed to assess the in vitro and in vivo effect of transfecting the IL-17 gene into tumor cells.

METHODS

A complementary DNA (cDNA) encoding human IL-17 (hIL-17) was obtained by polymerase chain reaction amplification from the human CD4+ T cell cDNA library and inserted into the plasmid pRc/cytomegalovirus to construct an expression vector for the hIL-17 gene. Murine Meth-A fibrosarcoma cells were transfected with the hIL-17 gene using the lipofectin method. The hIL-17 gene-expressing clone (Meth-A/IL-17) was selected and analyzed for cytokine expression by Northern blot.

RESULTS

There was no significant difference in the in vitro proliferation rate among parent Meth-A, cells transfected with vector alone and Meth-A/IL-17 cells. When the tumor cells were transplanted subcutaneously into BALB/c nude (nu+/nu+) mice, there was no difference in in vivo growth rates among the three cell lines. Challenge with tumor cells in conventional BALB/c mice, however, resulted in the rejection of Meth-A/IL-17 cells, but the other two lines did grow. After immunization with Meth-A/IL-17 cells, the mice were rechallenged by parent Meth-A or syngeneic MOPC-104E plasmacytoma cells; the immunized mice rejected the Meth-A cells, but not the MOPC-104E cells. Injecting the anti-thy 1,2 (CD90), anti-CD4 or anti-CD8 monoclonal antibody into conventional BALB/c mice resulted in the resumption of in vivo growth of Meth-A/IL-17 cells, but injecting the anti-asialo GM1 antibody did not. Furthermore, flow cytometric analysis demonstrated a significant increase in the expression of major histocompatibility complex (MHC) class I and class II antigens and lymphocyte function-associated antigen-1 on Meth-A/IL-17 cells.

CONCLUSION

Meth-A cells transfected with the hIL-17 gene can induce tumor-specific antitumor immunity by augmenting the expression of MHC class I and II antigens, and both CD4+ and CD8+ T cells may play important roles in inducing antitumor immunity, suggesting the possibility of developing a tumor vaccine incorporating IL-17-transfected tumor cells.

Pancreatic mass due to chronic pancreatitis: correlation of CT and MR imaging features with pathologic findings

OBJECTIVE

The purpose of this study was to identify helical CT and MR imaging features of pancreatic masses (focal enlargement) due to chronic pancreatitis and their correlation with pathologic findings.

CONCLUSION

When histologic fibrosis is uniformly present through the pancreas in patients with chronic pancreatitis, there is no demarcation of masses due to chronic pancreatitis. When there is a greater degree of histologic fibrosis in the masslike part of the pancreas, the mass is often demarcated from the remaining pancreas, and the enhancement pattern on two-phase helical CT and dynamic gadolinium-enhanced MR imaging mimics that of pancreatic adenocarcinoma.

Catalytic enantioselective Reissert-type reaction: development and application to the synthesis of a potent NMDA receptor antagonist (-)-L-689,560 using a solid-supported catalyst

Full details of the first catalytic enantioselective Reissert-type reaction are described. Utilizing the Lewis acid-Lewis base bifunctional catalyst 5 or 6 (9 mol %), the Reissert products were obtained in 57 to 99% yield with 54 to 96% ee. Electron-rich quinolines produced better yields and enantioselectivities than electron-deficient substrates. Kinetic studies indicated that the reaction should proceed via the rate-determining acyl quinolinium formation, followed by the attack of a cyanide. The catalyst does not facilitate the first rate-determining step; however, it strongly facilitates the second cyanation step. The reaction was successfully applied to an efficient catalytic asymmetric synthesis of a potent NMDA receptor antagonist (-)-L-689,560. A key step is the one-pot process using the Reissert-type reaction from quinoline 1f, followed by stereoselective reduction of the resulting enamine 2f. This step gave the key intermediate 20 in 91% yield with 93% ee, using 1 mol % of 6. The enantiomerically pure target compound was obtained through 10 operations (including recrystallization) in total yield of 47%. Furthermore, 6 was immobilized to JandaJEL, and the resulting solid-supported catalyst 11 afforded 20 in a comparable yield to the homogeneous 6, but with slightly lower enantioselectivity.

Microwave coagulation therapy with interruption of hepatic blood in- or outflow: an experimental study

PURPOSE

To determine how interruption of hepatic blood in- or outflow affects the coagulation diameter of microwave coagulation therapy (MCT) in the liver.

MATERIALS AND METHODS

Laparotomic MCT at 60 W for 1 minute was performed in 11 Landrace pigs. MCT was performed under six different conditions: without occlusion (Group N; in seven lobes of seven pigs); with occlusion of the hepatic artery (Group A; in five lobes of five pigs); with occlusion of the portal vein (Group P; in five lobes of five pigs); with occlusion of the hepatic artery and portal vein (Group AP; in six lobes of six pigs); with occlusion of the hepatic vein (Group V; in five lobes of four pigs); and with occlusion of the hepatic artery and vein (Group AV; in seven lobes of seven pigs). The maximum diameters for each group were compared.

RESULTS

The coagulation diameters (mean +/- SD) were 8.5 mm +/- 2.0, 10.0 mm +/- 1.6, 14.3 mm +/- 2.5, 14.4 mm +/- 2.4, 13.0 mm +/- 0.8, and 14.4 mm +/- 1.5 for Groups N, A, P, AP, V, and AV, respectively. The coagulation diameters for groups P, AP, V, and AV were statistically larger than those for groups N and A (P < .05). There was no significant difference between the coagulation diameters of Groups P, AP, V, and AV.

CONCLUSION

The coagulation diameter depends mainly on the portal venous flow. In addition of direct interruption of the portal vein, interruption of the hepatic vein can also result in a substantial increase in the coagulation diameter.

Acute epidural hematoma related to cesarean section in a neonate with Chiari II malformation

We present a rare case of acute epidural hematoma in a newborn infant with congenital hydrocephalus that was related to Chiari II malformation. The hematoma was attributed to the application of excessive suction with a vacuum extractor during cesarean section. The clinical characteristics of neonatal epidural hematoma were analyzed after a review of 18 cases in the literature, and diagnosis and treatment are discussed with reference to the results. We propose that careful follow-up is essential in neonates with cephalohematoma, and that a computed tomography (CT) study should be performed immediately if an infant's head circumference is discovered to be enlarging or if the anterior fontanel bulges.

Apoptosis and expression of Bcl-2 and Bax proteins in invasive ductal carcinoma of the pancreas

The Bcl-2 family of genes plays important roles in the regulation of apoptosis. The present study was designed to assess the clinicopathologic significance of apoptosis and the expression of the apoptosis-inhibitory Bcl-2 protein (pBcl-2) and the apoptosis-promoting Bax protein (pBax) in human invasive ductal carcinomas (IDCs) of the pancreas. The present study included 66 IDCs that were resected between 1982 and 1998. Apoptosis was assessed by the in situ nick end labeling method and pBcl-2 and pBax were stained immunohistochemically. Apoptosis was quantified as the apoptotic index (AI, the percentage of apoptotic cells of the total tumor cells), and a high AI (>10%) was observed in 26 of the 66 (39%) IDCs. The AI correlated significantly with the extent of nodal involvement. pBax immunoreactivity was detected in 42 of 66 IDCs (64%), and pBax expression was significantly correlated with female gender and showed a significant negative correlation with the extent of nodal involvement. pBcl-2 was expressed in 16 IDCs (24%) but did not show any correlation with the clinicopathologic factors. The AI did not correlate with the expression of pBcl-2 or pBax, but there was a significant correlation between the expression of pBcl-2 and that of pBax; 15 of the 16 pBcl-2(+)IDCs were also pBax(+), and only one pBcl-2(+)IDC was pBax(-). Univariate analysis demonstrated that the degree of apoptosis had no significant influence on the patients' prognosis, pBax or pBcl-2 expression was significantly associated with a better prognosis, and in particular, the pBax(+)pBcl-2(+) group had a significantly higher survival than the other groups. On the other hand, the survival curve of the adjuvant chemotherapy (ACT) group was also higher than that of the surgery alone (SA) group, with borderline statistical signfiicance. The ACT group showed a significantly better survival rate than the SA group for the pBax(+)IDC patients, but the AI and pBcl-2 expression were not correlated with an improved survival rate in the ACT group. Multivariate analysis showed that the AI. pBcl-2 expression, and pBax expression by themselves did not represent significant variables for death owing to IDC, but pBax expression was significantly associated with the efficacy of ACT. In conclusion, pBax expression may be essential for pBcl-2 expression. pBcl-2 and pBax expressions are not significant prognostic factors for patients with IDC, but pBax expression may be beneficial in predicting the effects of ACT on patients with IDC.

Inhibition of intrahepatic metastasis of human hepatocellular carcinoma by Rho-associated protein kinase inhibitor Y-27632

Intrahepatic metastasis is one of the most important prognostic factors for patients with hepatocellular carcinoma (HCC). Cell motility mediated by Rho- and p160 Rho-associated coiledcoil forming protein kinase (p160ROCK) signaling pathways has recently been shown to play a critical role in intrahepatic metastasis in human HCC. Furthermore, the stable introduction of dominant-negative p160ROCK into Li7 cells resulted in a reduced metastatic rate in mice with severe combined immunodeficiency (SCID). To investigate whether the specific p160ROCK inhibitor, Y-27632, could also inhibit intrahepatic metastasis, the effect of Y-27632 on the cell motility and intrahepatic metastasis of Li7 was investigated. Y-27632 markedly blocked actin reorganization and motility of Li7 cells mediated by lysophosphatidic acid (LPA). Y-27632 was administered continuously into the peritoneal cavity using a micro-osmotic pump, together with orthotopic implantation of Li7 cells into the liver of SCID mice. Phosphate-buffered saline (PBS) alone was administered as the control. The incidence of mice with metastatic nodules decreased in the Y-27632-treated group. The primary tumor volume at the site of injection was smaller in the Y-27632-treated group compared with the control group, but the difference was not statistically significant. Histologically, control tumors showed infiltrative growth into the sinusoidal area at the tumor boundary, whereas Y-27632-treated tumors showed expansive growth and low invasiveness. These findings confirm the importance of the Rho/p160ROCK signaling pathway in intrahepatic metastasis of human HCC, and indicate that Y-27632 may be useful for the prevention of intrahepatic metastasis of human HCC.

Hypervascular hepatocellular carcinoma: detection with double arterial phase multi-detector row helical CT

PURPOSE

To assess whether double arterial phase imaging with multi-detector row helical computed tomography improves detection of hypervascular hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Fifty-one patients with 96 hypervascular HCCs underwent double arterial phase imaging of the entire liver. At measured delay after intravenous administration of 2 mL/kg of contrast medium at a rate of 5 mL/sec, the early and late arterial phase images were obtained serially during a single breath hold with interscan delay of 5.0 seconds. Detector row configuration of 2.5 x 4 mm, pitch of 6, and scanning time of 10.5 seconds for each phase were used. Forty 5-mm-thick reconstruction images were obtained for each phase. Each image set was interpreted separately by three observers, who were unaware of tumor burden in the liver, to detect hypervascular HCC. Sensitivity, positive predictive value, and area below the receiver operating characteristic curve (A(z)) for early and late arterial phases separately and together were calculated.

RESULTS

Mean sensitivity and positive predictive value for hypervascular HCC were 54% and 85% for the early arterial phase, 78% and 83% for the late arterial phase, and 86% and 92% for the double arterial phase, respectively. Double arterial phase imaging showed significantly superior sensitivity compared with early or late arterial phase imaging alone for detecting HCC (P <.05). The mean A(z) value for double arterial phase was significantly higher than that for early or late arterial phase imaging alone (P <.05). Double arterial phase imaging showed the lowest number of false-positive lesions.

CONCLUSION

Double arterial phase imaging is recommended to improve detection of hypervascular HCCs and reduce false-positive lesions.

Evaluation of regional liver damage by magnetic resonance imaging with superparamagnetic iron oxide in rat liver

The purpose of this study was to investigate whether regional liver damage could be detected by means of enhanced MR imaging with a superparamagnetic iron oxide (SH U 555A) in an ischemia-reperfusion model of rat liver. Ischemic liver damage was induced in the right lobe by vascular clamping for 0 (sham), 30 (I-30), 60 (I-60), and 90 minutes (I-90). There was no significant difference in relative enhancement (RE) between the ischemic and nonischemic lobes in the sham, I-30 and I-60 groups, while RE of the ischemic lobe was significantly lower than that of its nonischemic counterpart in the I-90 group as seen on SH U 555A enhanced proton density spin echo images (P < 0.05). Histological examination revealed that iron deposits were significantly smaller in the ischemic than the nonischemic lobe in the I-90 group (P < 0.05), although there was no significant difference in the number of Kupffer cells. Our results indicate that severe regional liver damage can be evaluated by MR imaging with SH U 555A.

Influence of dual ET(A)/ET(B)-receptor blockade on coronary responses to treadmill exercise in dogs

We hypothesized that endothelin (ET) release during exercise may be triggered by alpha-adrenergic-receptor activation and thereby influence coronary hemodynamics and O(2) metabolism in dogs. Exercise resulted in coronary blood flow increases (to 1.88+/-0.26 from 1.10+/- 0.12 ml x min(-1) x g(-1)) and in a fall (P<0.01) in coronary sinus O(2) saturation (17.4+/-1.5 to 9.6+/-0.7 vol%), whereas myocardial O(2) consumption (MVO(2)) increased (109+/-13% from 145+/-16 microl O(2) min(-1) x g(-1)). Tezosentan, a dual ET(A)/ET(B)-receptor blocker, slightly reduced mean arterial pressure (MAP) and increased heart rate throughout exercise. The relationship between coronary sinus O(2) saturation and MVO(2) was shifted upward (P<0.05) after tezosentan administration; i.e., as MVO(2) increased during exercise, coronary sinus O(2) saturation was disproportionately higher after ET-receptor blockade. After propranolol, tezosentan resulted in significant decreases (P<0.05) in left ventricular pressure, the first derivative of left ventricular pressure over time, and MAP during exercise. As MVO(2) increased during exercise, coronary sinus O(2) saturation levels after tezosentan became superimposable over those observed before ET-receptor blockade. Thus dual blockade of ET(A)/ET(B) receptors alters coronary hemodynamics and O(2) metabolism during exercise, but ET activity failed to increase beyond baseline levels.