Characterizing hepatocellular carcinoma using multi-breath-hold two-dimensional susceptibility-weighted imaging: comparison to conventional liver MRI

AIM

To characterize the imaging manifestations of hepatocellular carcinoma (HCC) using multi-breath-hold two-dimensional susceptibility-weighted imaging (SWI) and compare to conventional liver magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Forty-three patients with histopathologically confirmed HCC underwent conventional liver MRI, multi-breath-hold two-dimensional SWI, and contrast-enhanced CT preoperatively. The T1-weighted imaging (WI), T2WI, and SWI images were evaluated in consensus by two experienced radiologists. The tumour boundaries, blood products in the tumour, venous vessels, and non-tumour liver parenchyma were compared.

RESULTS

SWI demonstrated significantly better tumour boundary detection than T1WI and T2WI imaging (67.4 and 25.6%, respectively). The detection rate for intra-tumoural blood products using SWI was higher than that of T1WI and T2WI (76.7 and 16.3%, respectively). The detection rate for tumour venous vessels using SWI was 72.1%, while none was detected with conventional T1WI and T2WI. The detection rate for siderotic nodules in non-tumour liver parenchyma using SWI was higher than that of conventional T1WI and T2WI (65.1 and 20.9%, respectively).

CONCLUSIONS

SWI can provide more detailed information than conventional liver MRI in evaluation of tumour boundaries, blood products, venous vasculature, and non-tumour liver parenchyma. SWI is a valuable complement to conventional liver MRI.

Expression of CaV3.2 T-type Ca²⁺ channels in a subpopulation of retinal type-3 cone bipolar cells

Retinal bipolar cells and ganglion cells are known to possess voltage-gated T-type Ca(2+) channels. Previous electrophysiological recording studies suggested that there is differential expression of different T-type Ca(2+) channel α1 subunits among bipolar cells. The detailed expression patterns of the individual T-type Ca(2+) channel subunits in the retina, however, remain unknown. In this study, we examined the expression of the Ca(V)3.2 Ca(2+) channel α1 subunit in the mouse retina using immunohistochemical analysis and patch-clamp recordings together with a Ca(V)3.2 knock out (KO) mouse line. The specificity of a Ca(V)3.2 Ca(2+) channel antibody was first confirmed in recombinant T-type Ca(2+) channels expressed in human embryonic kidney (HEK) cells and in Ca(V)3.2 KO mice. Our immunohistochemical analysis indicates that the Ca(V)3.2 antibody labels a subgroup of type-3 cone bipolar cells (CBCs), the PKAβII-immunopositive type-3 CBCs. The labeling was observed throughout the cell including dendrites and axon terminals. Our patch-clamp recording results further demonstrate that Ca(V)3.2 Ca(2+) channels contribute to the T-type Ca(2+) current in a subpopulation of type-3 CBCs. The findings of this study provide new insights into understanding the functional roles of T-type Ca(2+) channels in retinal processing.

Insulin clearance: confirmation as a highly heritable trait, and genome-wide linkage analysis

AIMS/HYPOTHESIS

We have previously documented a high heritability of insulin clearance in a Hispanic cohort. Here, our goal was to confirm the high heritability in a second cohort and search for genetic loci contributing to insulin clearance.

METHODS

Hyperinsulinaemic-euglycaemic clamps were performed in 513 participants from 140 Hispanic families. Heritability was estimated for clamp-derived insulin clearance and a two-phase genome-wide linkage scan was conducted using a variance components approach. Linkage peaks were further investigated by candidate gene association analysis in two cohorts.

RESULTS

The covariate-adjusted heritability of insulin clearance was 73%, indicating that the majority of the phenotypic variance is due to genetic factors. In the Phase 1 linkage scan, no signals with a logarithm of odds (LOD) score >2 were detected. In the Phase 2 scan, two linkage peaks with an LOD >2 for insulin clearance were identified on chromosomes 15 (LOD 3.62) and 20 (LOD 2.43). These loci harbour several promising candidate genes for insulin clearance, with 12 single nucleotide polymorphisms (SNPs) on chromosome 15 and six SNPs on chromosome 20 being associated with insulin clearance in both Hispanic cohorts.

CONCLUSIONS/INTERPRETATION

In a second Hispanic cohort, we confirmed that insulin clearance is a highly heritable trait and identified chromosomal loci that harbour genes regulating insulin clearance. The identification of such genes may improve our understanding of how the body clears insulin, thus leading to improved risk assessment, diagnosis, prevention and therapy of diabetes, as well as of other hyperinsulinaemic disorders, such as the metabolic syndrome and polycystic ovary syndrome.

Lysine-specific demethylase 1: an epigenetic regulator of salt-sensitive hypertension

BACKGROUND

Hypertension (HTN) represents a complex heritable disease in which environmental factors may directly affect gene function via epigenetic mechanisms. The aim of this study was to test the hypothesis that dietary salt influences the activity of a histone-modifying enzyme, lysine-specific demethylase 1 (LSD-1), which in turn is associated with salt-sensitivity of blood pressure (BP).

METHODS

Animal and human studies were performed. Salt-sensitivity of LSD-1 expression was assessed in wild-type (WT) and LSD-1 heterozygote knockout (LSD-1(+/-)) mice. Clinical relevance was tested by multivariate associations between single-nuclear polymorphisms (SNPs) in the LSD-1 gene and salt-sensitivity of BP, with control of dietary sodium, in a primary African-American hypertensive cohort and two replication hypertensive cohorts (Caucasian and Mexican-American).

RESULTS

LSD-1 expression was modified by dietary salt in WT mice with lower levels associated with liberal salt intake. LSD-1(+/-) mice expressed lower LSD-1 protein levels than WT mice in kidney tissue. Similar to LSD-1(+/-) mice, African-American minor allele carriers of two LSD-1 SNPs displayed greater change in systolic BP (SBP) in response to change from low to liberal salt diet (rs671357, P = 0.01; rs587168, P = 0.005). This association was replicated in the Hispanic (rs587168, P = 0.04) but not the Caucasian cohort. Exploratory analyses demonstrated decreased serum aldosterone concentrations in African-American minor allele carriers similar to findings in the LSD-1(+/-) mice, decreased α-EnaC expression in LSD-1(+/-) mice, and impaired renovascular responsiveness to salt loading in minor allele carriers.

CONCLUSION

The results of this translational research study support a role for LSD-1 in the pathogenesis of salt-sensitive HTN.

Peak expiratory flow as a screening tool to detect airflow obstruction in a primary health care setting

BACKGROUND

Peak expiratory flow (PEF) measurement is less expensive and requires fewer skills than spirometry testing. It is thus expected to be a reasonable substitute for spirometry in airflow obstruction screening when spirometry is unavailable.

OBJECTIVES

To evaluate the validation of PEF measurement in the detection of airflow obstruction using newly established regression equations.

METHODS

The PEFs of 553 'normal' participants aged 40-85 years were measured using mechanical devices. Based on these data, regression equations were generated to predict normal PEF values. Data were then collected from 3379 subjects. The specificity and sensitivity of the different predicted PEF cut-off points for detecting airflow obstruction were evaluated by spirometry, based on previously generated regression equations.

RESULTS

Using newly established reference values for PEF, PEF had higher sensitivity and specificity than the questionnaire in detection of airflow obstruction. That PEF < 80% of predicted was more effective in the detection of airflow obstruction was confirmed by the lower limit of normal of forced expiratory volume in 1 second/forced vital capacity, Global Initiative for Chronic Obstructive Lung Disease (GOLD), and GOLD plus symptom, with a sensitivity of 78.7%, 76.8%, 85.3% and a specificity of 81.9%, 83.8%, 81.4%, respectively.

CONCLUSIONS

Mechanical PEF may be a reasonable method of screening for airflow obstruction in settings where spirometry is unavailable.

Selenoprotein dSelK in Drosophila elevates release of Ca2+ from endoplasmic reticulum by upregulating expression of inositol 1,4,5-tris-phosphate receptor

dSelK (G-rich), a homolog of human and mouse SelK, is one of three selenoproteins in Drosophila melanogaster. It is the only trans-membrane selenoprotein in D. melanogaster integrated into both the endoplasmic reticulum (ER) membrane and the Golgi apparatus. The gene expression profile of Drosophila Schneider 2 (S2) cells after the dsRNA interference (dsRNAi) targeting of dSelK was examined with the GeneChip Drosophila Genome 2.0 Array (Affymetrix), a high-density oligonucleotide microarray encompassing nearly the full Drosophila genome. The results showed that the transcriptional expression of eight genes whose proteins are located on (or related to) the ER or the Golgi apparatus was highly induced or repressed by the dsRNAi treatment. The mRNA levels of the inositol 1,4,5-tris-phosphate receptor (IP3 receptor), whose gene product is integrated into the ER membrane and regulates the release of Ca2+ from the ER to the cytosol, were significantly downregulated. In contrast, the expression of inositol 1,4,5-tris-phosphate kinase 1, which is a cytosolic protein with opposing functions to the IP3 receptor, was significantly upregulated. Quantitative real-time PCR verified these results. The concentration of intracellular free Ca2+ of the Drosophila S2 cells was significantly decreased after the knockdown of dSelK, whereas overexpression of dSelK significantly increased the intracellular free Ca2+ concentration. These results indicate that dSelK in D. melanogaster is involved in regulating the release of Ca2+ from the ER to the cytosol and may play important roles in the signal transduction pathways involving Ca2+ mobilization.

Solid state 27Al NMR investigation of Knight shift tensors of LnAl2 (Ln = Y, La and Lu) and correlation with DFT calculations

The atomic and electronic structures of LnAl(2) (Ln=Y, La and Lu) on Al sites were characterized by (27)Al solid state NMR spectroscopy. (27)Al isotropic metallic shifts have been determined in these cubic laves phases under both static and magic angle spinning (MAS) conditions. Based on band structure calculations, we found a strong correlation of (27)Al isotropic metallic shifts and s character of the density of states at the Fermi level on Al sites. We also found tetrahedral distortion of Al centered clusters, which can be well characterized by quadruple coupling constants and Knight shift anisotropy.

Spatial-temporal expression of pum1 and pum2 in medaka Oryzias latipes

Two pumilios, pum1 and pum2, were identified in medaka Oryzias latipes. Oryzias latipes pum1 and pum2 are ubiquitous in the adult tissues but with specific expression in the germ cells of gonads, ovary and testis. Pum1 is expressed in the spermatogonia to spermatocytes whilst pum2 presents in spermatocytes of testis only. Oryzias latipes pum1 and pum2 are maternally supplied RNA with ubiquitous expression in the early stages, and embryonic expression of pum1 and pum2 may begin from early gastrula. Both pum1 and pum2 are expressed in the tissues including brain, eye and trunk, and both are expressed in the gonads after hatching. Taken together, Pum1 and Pum2 may play important roles in embryonic and germ cell development of O. latipes.

Acceptable warm ischemia time of tracheal grafts from non-heart-beating donors in rats

OBJECTIVES

Warm ischemia (WI)-induced airway complications are common in clinical lung transplantation. However, the acceptable WI time of tracheal grafts from non-heart-beating donors (NHBDs) is unknown. The purpose of this study was to determine the acceptable WI time by observing tracheal epithelial regeneration among NHBD.

METHOD

Forty-eight rats were randomly divided into four groups (each with 12 rats): WI-0 minutes (group A), WI-30 minutes (group B), WI-45 minutes (group C), and WI-60 minutes (group D). In each group, the tracheas from 6 rats were imbedded in the greater omentum of 6 other rats. Fourteen days later, the transplanted trachea was obtained from the recipient to evaluate epithelial thickness and regeneration. Six tracheas were obtained from living donors as a control group.

RESULTS

There were no significant differences in tracheal transplantation time (mean, 17.66±1.21 minutes). There were no significant differences in epithelial thickness and regeneration between the controls and groups A, B, and C (P<.05). Group D showed no normal epithelial structure of the trachea only with monolayer cells.

CONCLUSIONS

The time limits of tolerance to WI of tracheal grafts from NHBDs may be 45 minutes.

Implications of QRS duration in dogs with pacing-induced heart failure

The objective of this study was to find out the implication of QRS duration in dogs with rapid pacing-induced heart failure. Sixteen Beagle dogs were implanted with transvenous cardiac pacemakers and underwent rapid right ventricular pacing for 3 weeks at 260 bpm to induce heart failure. Dogs were divided into two groups according to the QRS duration: 9 with normal QRS duration (<100 ms) and 7 with prolonged QRS duration (≥100 ms). Cardiac systolic function and size was analyzed by real time 3-dimensional echocardiography and left ventricular dyssynchrony was assessed by speckle tracking strain imaging. Congestive heart failure developed 3 weeks after rapid right ventricular pacing. Dogs with prolonged QRS duration showed more extensive radial strain and circumferential strain dyssynchrony than dogs with normal QRS duration. At the end of 4-week recovery, greater improvement of left ventricular ejection fraction and left ventricular end-systolic volume was detected in dogs with normal QRS duration. The findings suggested that left ventricular dyssynchrony, indicated by a prolonged QRS duration, predicted an unsatisfying recovery in dogs with rapid pacing-induced heart failure. QRS duration had the potential to be a prognostic indicator for dogs with heart failure.

SIRT1 RNAi knockdown induces apoptosis and senescence, inhibits invasion and enhances chemosensitivity in pancreatic cancer cells

The NAD(+)-dependent deacetylase, sirtuin 1 (SIRT1), has been recently been suspected to have a role in tumorigenesis. We investigated the expression of SIRT1 in pancreatic cancer and the effect of SIRT1-targeted RNA interference (RNAi) on cell proliferation and tumor formation in a pancreatic cancer cell line, PANC1. The expression of SIRT1 was investigated in 49 specimens of pancreatic cancer and adjacent normal pancreatic tissues. SIRT1 was overexpressed in pancreatic cancer tissues at both the mRNA and protein levels, with increased SIRT1 positivity associated with tumors from patients over 60 years old, tumors larger than 4 cm, higher TNM (extent of tumor (T), the extent of spread to lymph nodes (N), and presence of distant metastasis (M)) stage or the presence of lymph node or hepatic metastases. The PANC-1 was stably transfected with a SIRT1 small hairpin RNA (shRNA) expression plasmid and compared with untransfected and PANC-1-negative RNAi cells. Proliferation of PANC-1-SIRT1-RNAi cells was significantly reduced, accompanied by increased rates of apoptosis, G1 arrest and senescence. Furthermore, FOXO3a expression was markedly upregulated in PANC-1-SIRT1-RNAi cells, but no significant difference in p53 expression was observed. The invasive ability of PANC-1-SIRT1-RNAi cells was markedly reduced in vitro, which was linked to increased E-cadherin and reduced-MMP expression. Additionally, PANC-1-SIRT1-RNAi cells had a significantly reduced capacity to form tumors in vivo compared with untransfected and PANC-1-negative RNAi cells. These results suggest that SIRT1 may promote cell proliferation and tumor formation in pancreatic cancer, and downregulation of SIRT1 using shRNA could provide a novel therapeutic treatment.