Potential role of a navigator gene NAV3 in colorectal cancer.

BACKGROUND: The recently described navigator proteins have a multifaceted role in cytoskeletal dynamics. We report here on the relevance of one of them, navigator 3 (NAV3), in colorectal cancer (CRC). METHODS: We analysed changes in chromosome 12 and NAV3 copy number in CRC/adenoma samples of 59 patients and in 6 CRC cell lines, using fluorescence in situ hybridisation, loss of heterozygosity, and array-CGH. NAV3 target genes were identified by siRNA depletion, expression arrays, and immunohistochemistry. RESULTS: NAV3 deletion and chromosome 12 polysomy were detected in 30 and 70% of microsatellite stability (MSS) carcinomas, in 23 and 30% of adenomas and in four of six CRC cell lines. NAV3 amplification was found in 25% of MSS samples. NAV3 alterations correlated with lymph node metastasis. In normal colon cells, NAV3 silencing induced upregulation of interleukin 23 receptor (IL23R) and gonadotropin releasing hormone receptor. In MSS and microsatellite instability tumours, IL23R immunoreactivity correlated with Dukes' staging and lymph node metastases, whereas nuclear beta-catenin correlated with lymph node metastases only. CONCLUSION: NAV3 copy number changes are frequent in CRC and in adenomas, and upregulation of IL23R, following NAV3 silencing, strongly correlates with Dukes' staging and lymph node metastases. This suggests that NAV3 has a role in linking tissue inflammation to cancer development in the colon.

Characterization of cDNAs for mouse lysyl hydroxylase 1, 2 and 3, their phylogenetic analysis and tissue-specific expression in the mouse.

We report on the isolation and characterization of cDNA clones for mouse lysyl hydroxylases 1, 2 and 3 (LH1, LH2, LH3). Phylogenetic analysis using nine lysyl hydroxylase sequences from five species indicates that the isoforms are derived from an ancestral gene by two duplication events, isoforms 1 and 2 being more closely related and having resulted from a more recent duplication than isoform 3. Expression of the isoforms is highly regulated in adult mouse tissues. LH1 is strongly expressed in the liver, heart, lung, skeletal muscle and kidney tissue, LH2 expression is high in the heart, lung, kidney, eye, ovary and placenta, whereas LH3 expression is high in the heart, lung, liver and testis tissue.

Complete genomic structure of mouse lysyl hydroxylase 2 and lysyl hydroxylase 3/collagen glucosyltransferase.

Lysyl hydroxylase is an enzyme involved in collagen biosynthesis, catalyzing the hydroxylation of lysyl residues as a post-translational event. Three isoforms have been characterized so far (LH1, LH2, LH3). Our recent findings indicate that LH3 possesses, not only lysyl hydroxylase activity, but also galactosylhydroxylysyl glucosyltransferase activity [Heikkinen et al., J. Biol. Chem. 275 (2000) 36158-36163]. We report here the characterization of mouse LH2 (Plod2) and LH3/glucosyltransferase (Plod3) genes. Plod2 spans approximately 50 kb of the genomic DNA, and is organized in 20 exons, one of the exons being alternatively spliced in the RNA processing. Plod3 spans approximately 10 kb of the genomic DNA, and contains 19 exons. Analysis of the 5' flanking region with many transcription start sites reveals the lack of a TATAA box in both genes. Sequence analysis indicated many retroposon-like elements within the Plod3 gene. A comparison was carried out among the LH1, LH2 and LH3 gene structures characterized so far from different species.

Multislice MRI in assessment of myocardial perfusion in patients with single-vessel proximal left anterior descending coronary artery disease before and after revascularization.

BACKGROUND: Our purpose was to use multislice MRI for detection of reversible myocardial ischemia and assessment of the effect of revascularization on tissue perfusion in patients with coronary artery disease. METHODS AND RESULTS: Eleven patients with single-vessel proximal left anterior descending coronary artery disease were studied with MRI and thallium scintigraphy before and 3 months after revascularization. All patients had a reversible perfusion defect by scintigraphy before treatment. With a 1.5-T MR imager, IR-prepared turboflash images were acquired in three left ventricular short-axis planes during 0.05 mmol/kg Gd-DTPA bolus at rest and with dipyridamole-induced stress. Before treatment, stress increased enhancement slope in normal (6.4+/-4.4 to 7.4+/-5.0 s(-1), P<.04) and decreased it in underperfused (5.4+/-3.7 to 2.6+/-1.4 s(-1), P<.02) regions, resulting in a contrast-to-noise ratio of 6.87+/-3.09 in underperfused myocardium. Revascularization normalized enhancement patterns of the formerly underperfused myocardium and decreased defect size both in scintigraphy (66+/-53 degrees to 8+/-12 degrees, P<.001) and MRI sections (49+/-41 degrees to 9+/-8 degrees, P<.001). Agreement of 85% in detection and correlation of 0.86 (SEE, 21 degrees, P<.001) in sizing perfusion defects was found between MRI and scintigraphy. CONCLUSIONS: Multislice contrast-enhanced MRI can be used to detect myocardial perfusion defects in patients with coronary artery disease and in assessment of the effect of treatment on myocardial perfusion.

Atypical juvenile neuronal ceroid lipofuscinosis with granular osmiophilic deposit-like inclusions in the autonomic nerve cells of the gut wall.

In this 8-year-old boy, who had been exposed to alcohol and oxazepam during pregnancy, visual failure was the first symptom of a neuronal ceroid lipofuscinosis (NCL) disorder, noticed at the age of 5 years. Ophthalmological examinations revealed a cystic type of macular degeneration, which would be more likely to be found in variant late infantile NCL. However, vacuolated lymphocytes were found in peripheral blood films and a diagnosis of the juvenile form of NCL (JNCL) was made. Molecular genetic studies showed the patient to be homozygous for the major mutation of JNCL, a 1.02-kb deletion. In whole-night polysomnography, there was significantly more epileptiform activity than in other JNCL patients under 10 years of age. Using magnetic resonance imaging, the signal intensity of the white matter was increased, especially in the periventricular area. In addition, there were enlarged perivascular spaces in the watershead areas. The corpus callosum was thin. Finally, in the autonomic ganglion cells of the submucosal nerve plexus there were membrane-enclosed homogeneous and granular cytosomes resembling the granular osmiophilic deposits of infantile NCL. However, extraneural cells, including blood capillaries and smooth muscle, showed inclusions with fingerprint and curvilinear profiles. The features of the present case indicated a phenotypic variant of JNCL.

Improvement of brain lesion detection at 0.1 T by simultaneous use of Gd-DTPA and magnetization transfer imaging.

Imaging parameters were optimized at 0.1 T to improve contrast-to-noise ratios (CNR) when combining magnetization transfer (MT) imaging and the use of paramagnetic contrast medium. This was accomplished by imaging a phantom containing serial concentrations of Gd-DTPA in cross-linked bovine serum albumin. With the use of simulations, the dependence of CNR on imaging parameters was studied. Conventional and MT images were obtained from 10 brain tumor patients with single and triple doses of Gd-DTPA. Simulations demonstrated the importance of TR in postcontrast sequences. The CNR in MT images is less sensitive to TR than in conventional images. A significant CNR improvement caused by MT remains at longer TR when there is no contrast enhancement without MT. The clinical results indicate that a single dose of Gd-DTPA combined with MT cannot replace imaging with a triple dose. However, MT significantly improved the CNR after single and triple Gd-DTPA-doses on T1-weighted and proton-density images.

T1 rho dispersion imaging of head and neck tumors: a comparison to spin lock and magnetization transfer techniques.

The potential of T1 rho dispersion, spin lock (SL), and magnetization transfer (MT) techniques to differentiate benign and malignant head and neck tumors was evaluated. Twenty-four patients with pathologically verified head and neck tumors were studied with a .1-T MR imager. T1 rho dispersion effect was defined as 1 -(intensity with lower locking field amplitude/intensity with higher locking field amplitude). T1 rho dispersion effects were higher for malignant than benign tumors (P = .001). With T1 rho dispersion effect .14 as the threshold, sensitivity for detecting a malignant tumor was 91%, specificity was 77%, and accuracy was 83%. A strong correlation between T1 rho dispersion effects and SL effects and between T1 rho dispersion effects and MT effects in the head and neck tumors was found (r = .87, P < .001 and r = .90, P < .001, respectively). High T1 rho dispersion effects are not specific indicators of malignancy, because chronic infections, some benign tumors, and malignancies may overlap. Low T1 rho dispersion effect values are characteristic of a benign tumor.

Spin lock and magnetization transfer imaging of head and neck tumors.

PURPOSE: To evaluate and compare the spin lock and magnetization transfer techniques in the differentiation of benign and malignant head and neck tumors at magnetic resonance (MR) imaging. MATERIALS AND METHODS: Forty consecutive patients with histologically verified head and neck tumors (20 malignant and 20 benign tumors, including five infections) were studied with a 0.1-T MR unit. The spin lock and magnetization transfer effects were defined as 1-(signal intensity with stronger preparation pulse/signal intensity with weaker preparation pulse). RESULTS: A strong correlation between the spin lock and magnetization transfer effects was found (r = 85, P < .001). With a spin lock effect of 0.48 and a magnetization transfer effect of 0.32 as the thresholds, sensitivity for detecting a malignant tumor was 95% and 94%, respectively, and specificity was 60% and 65%. CONCLUSION: Low spin lock and magnetization transfer effects are characteristic of benign tumors. High spin lock and magnetization transfer effects were associated with malignancy, but there were overlapping values for salivary gland infections, some benign tumors, and malignancies. The spin lock technique seems to be an effective method for generating magnetization transfer-based contrast in the head and neck tumors.