Cardiac Computed Tomography-Derived Left Atrial Strain and Volume in Pediatric Patients With Congenital Heart Disease: A Comparative Analysis With Transthoracic Echocardiography

Purpose

This study aimed at exploring the feasibility and reproducibility of CCT for the measurement of Left Atrial (LA) strain and volume compared with transthoracic echocardiography (TTE) in pediatric patients with congenital heart disease (CHD).

Materials and Methods

The present study included 43 postoperative patients with CHD (7.39 ± 3.64 years, 56% male) who underwent clinically indicated CCT, and all patients underwent additional TTE on the same day. LA strain and volume parameters were measured by dedicated software. The correlation and agreement of LA strain and volume parameters were assessed using Pearson’s correlation coefficient and Bland-Altman analysis. Intra-class correlation coefficients (ICC) were used to assess CCT intra-observer and inter-observer reproducibility.

Results

All strain parameters of CCT were lower compared to TTE (reservoir strain: 28.37 ± 6.92 vs. 32.15 ± 8.15, respectively; conduit strain: 21.33 ± 6.46 vs. 24.23 ± 7.75, respectively; booster strain: 7.04 ± 2.74 vs. 7.92 ± 3.56). While the volume parameters of CCT were higher compared to TTE (LAV: 29.60 ± 19.01 vs. 25.66 ± 17.60, respectively; LAVi: 30.36 ± 22.31 vs. 28.63 ± 19.25, respectively). Both LA strain and volume measurements showed good correlation and agreement between the two modalities (r = 0.63–0.87, p < 0.001). CT-derived LA strain and volume measurements showed good intra- and inter-observer reproducibility using prototype software (ICC = 0.78–0.96).

Conclusions

CCT was feasible for measuring LA strain and volume with good correlation and high reproducibility as compared with TTE. As a complementary modality, CCT can regard as an accepted method in the evaluation of LA function in pediatric patients with CHD

Feasibility of Three-Dimensional Balanced Steady-State Free Precession Cine Magnetic Resonance Imaging Combined with an Image Denoising Technique to Evaluate Cardiac Function in Children with Repaired Tetralogy of Fallot

Objective

To investigate the feasibility of cine three-dimensional (3D) balanced steady-state free precession (b-SSFP) imaging combined with a non-local means (NLM) algorithm for image denoising in evaluating cardiac function in children with repaired tetralogy of Fallot (rTOF).

Materials and Methods

Thirty-five patients with rTOF (mean age, 12 years; range, 7–18 years) were enrolled to undergo cardiac cine image acquisition, including two-dimensional (2D) b-SSFP, 3D b-SSFP, and 3D b-SSFP combined with NLM. End-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), and ejection fraction (EF) of the two ventricles were measured and indexed by body surface index. Acquisition time and image quality were recorded and compared among the three imaging sequences.

Results

3D b-SSFP with denoising vs. 2D b-SSFP had high correlation coefficients for EDV, ESV, SV, and EF of the left (0.959–0.991; p < 0.001) as well as right (0.755–0.965; p < 0.001) ventricular metrics. The image acquisition time ± standard deviation (SD) was 25.1 ± 2.4 seconds for 3D b-SSFP compared with 277.6 ± 0.7 seconds for 2D b-SSFP, indicating a significantly shorter time with the 3D than the 2D sequence (p < 0.001). Image quality score was better with 3D b-SSFP combined with denoising than with 3D b-SSFP (mean ± SD, 3.8 ± 0.6 vs. 3.5 ± 0.6; p = 0.005). Signal-to-noise ratios for blood and myocardium as well as contrast between blood and myocardium were higher for 3D b-SSFP combined with denoising than for 3D b-SSFP (p < 0.05 for all but septal myocardium).

Conclusion

The 3D b-SSFP sequence can significantly reduce acquisition time compared to the 2D b-SSFP sequence for cine imaging in the evaluation of ventricular function in children with rTOF, and its quality can be further improved by combining it with an NLM denoising method.

Postoperative evaluation of left ventricular global strain using cardiac computed tomography in pediatric patients with congenital heart disease: A comparison with echocardiography

PURPOSE

We explored the feasibility and reproducibility of cardiac computed tomography (CCT)-derived left ventricular (LV) global strain in postoperative children
with congenital heart disease (CHD) and compared its correlation and agreement with transthoracic echocardiography (TTE).

METHODS

Fifty-one patients (28 males, 23 females) were included who underwent clinically indicated retrospective electrocardiography-triggered CCT. and all patients underwent additional TTE on the same day. LV global longitudinal strain (GLS), global circumferential strain (GCS), and global radial strain (GRS) were measured. Correlations of global strains between CCT and TTE were assessed using Pearson's correlation coefficient. Intra-class correlation coefficients (ICC) were used to assess CCT intra-observer and inter-observer reproducibility.

RESULTS

GLS and GCS were not significantly different between CCT and TTE (GLS: -23.54 ± 3.24 vs. -23.85 ± 3.72, respectively, p = 0.415; GCS: -28.21 ± 3.55 vs. -28.79 ± 3.69, respectively, p = 0.155). GRS was significantly different between CCT and TTE (60.79 ± 15.11 vs. 41.73 ± 4.27, respectively, p < 0.001). There was good correlation between CCT- and TTE-derived GLS (r = 0.70, p < 0.001) and GCS (r = 0.68, p < 0.001), but GRS showed no correlation between CCT and TTE (r = 0.09, p = 0.54). CCT-derived global strain showed good intra- and inter-observer reproducibility (ICC = 0.86-0.92), except the inter-observer reproducibility for GRS (ICC = 0.77).

CONCLUSIONS

CCT was feasible for postoperative evaluation of LV global strain in pediatric patients with CHD with sufficient reproducibility. CCT-derived global strain can provide additional information in selected CHD patients with poor acoustic windows and who are intolerant to or have contraindications for cardiac magnetic resonance.

Hypomethylation of CTCFL promoters as a noninvasive biomarker in plasma from patients with hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the third deadliest cancer in the world with high morbidity and poor prognosis. CTCFL (CCCTC-binding factor like) is a member of the cancer testis antigen (CTA) family with oncogenic properties. To demonstrate whether the hypomethylation of CTCFL promoters in plasma could be used as a noninvasive biomarker to predict poor prognosis of HCC, we extracted cell-free DNA from the plasma and detected the methylation status of CTCFL in 43 HCC, 5 liver cirrhosis and 6 benign lesion samples using methylation specific PCR (MSP). Our study indicated that the hypomethylation of CTCFL promoters in HCC plasma samples (60.4%) was significantly different from that in benign lesion plasma samples (16.7%) with a p-value of 0.043. Analysis of clinicopathological data showed that the methylation status of CTCFL promoters was significantly correlated with microvascular involvement (MVI) (p=0.001) and postoperative recurrence (p=0.031). Furthermore, clinical prognosis data of 347 HCC patients from The Cancer Genome Atlas (TCGA) database displayed that the hypomethylated group had worse overall survival than the hypermethylated group (p=0.0056). In conclusion, we provide evidence that the hypomethylation of CTCFL promoters in cell-free DNA is a biomarker for monitoring HCC patients, which can be used as a noninvasive prediction index for tumor recurrence and provide the individualized decision-making for clinicians.

Systemic ventricular strain and torsion are predictive of elevated serum NT-proBNP in Fontan patients: a magnetic resonance study

Background

This study aimed to investigate the associations between cardiac strain, cardiac torsion, ventricular volumes, and ventricular ejection fraction, with N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels in Fontan patients who were age- and gender-matched with healthy control subjects.

Methods

Cardiovascular magnetic resonance (CMR) studies performed in 22 (15 male, 7 female) patients with single-ventricle physiology (all morphological left ventricles) palliated with Fontan and 17 (10 male, 7 female) age- and gender-matched healthy children volunteers were retrospectively analyzed. Serum NT-proBNP levels were obtained in Fontan subjects. Standard post-processing of CMR images included systemic ventricular end-diastolic and end-systolic volumes, stroke volume, cardiac mass, atrioventricular regurgitation, and ejection fraction. CMR tissue tracking (TT) software was used to quantify global longitudinal strain (GLS), global radial strain (GRS), and global circumferential strain (GCS) and torsion of the systemic ventricle. Pearson and Spearman correlation coefficients were used in comparisons of correlations between NT-proBNP and functional parameters in repair Fontan patients. Intra-observer and inter-observer variability of CMR strain and torsion values were determined from 10 randomly selected Fontan subjects and 10 randomly selected control subjects.

Results

GLS was significantly lower in Fontan patients than in control subjects (-15.19±2.94 vs. -19.97±1.70; P<0.001). GLS was not significantly different between normal NT-proBNP levels and high NT-proBNP levels in Fontan patients (-15.59±2.72 vs. -14.62±3.32; P=0.462). The GCS of repair Fontan patients was not significantly lower than that of the control group (-16.76±3.27 vs. -17.88±2.26; P=0.235). GCS was significantly different between normal and high NT-proBNP levels group in Fontan patients (-17.95±2.43 vs. -15.04±3.67; P=0.036). The peak systolic torsion and peak systolic torsion rates were significantly lower in Fontan patients than in control subjects (0.81±0.41 vs. 1.07±0.36, P=0.044; 7.36±3.41 vs. 9.85±2.61, P=0.017). Peak systolic torsion was significantly lower in Fontan patients with normal NT-proBNP levels than in high NT-proBNP subjects (0.67±0.43 vs. 1.01±0.29; P=0.036). GCS and torsion were more strongly correlated with NT-proBNP in the patient group (r=0.541 for GCS; r=0.588 for torsion, P<0.01). The parameters of strain and torsion could be reproduced with sufficient accuracy by intra-observer agreement(biases =0.04 for GLS; biases =0.66 for GCS; biases =1.03 for GRS; biases =0.04 for torsion) and inter-observer agreement (biases =0.32 for GLS; biases =0.85 for GCS; biases =1.52 for GRS; biases =0.18 for torsion).

Conclusions

GLS is an earlier marker of contractile dysfunction in repair Fontan patients. Peak systolic torsion may be a biomarker for determining subclinical dysfunction, as it is more strongly correlated with serum biomarkers of ventricular function than ventricular size or ejection fraction.

Combination of LINE-1 hypomethylation and RASSF1A promoter hypermethylation in serum DNA is a non-invasion prognostic biomarker for early recurrence of hepatocellular carcinoma after curative resection

Hepatocarcinogenesis, a multistep process, involves not only genetic mutations but also epigenetic alterations. Widespread of global DNA hypomethylation is accompanied with specific regional hypermethylation especially at tumor suppressor genes' promoters. The aim of this study is to determine the efficacy of combined DNA methylation analysis of a global DNA methylation marker - LINE-1 and a tumor suppressor gene highly associated with the malignancy of HCC- RASSF1A in serum as a novel prognostic marker for diagnosis of early recurrence after curative resection.LINE-1 was hypomethylated in 66.7% (70/105) and RASSF1A promoter was hypermethylated in 73.3% (77/105) of HCC serum DNA samples by methylation specific PCR, but in none of the healthy controls: LINE-1 hypometylation (0/50) and RASSF1A hypermethylation (0/50). A significant association was found between LINE-1 hypomethylation and clinical pathologic features including HBsAg positivity (p=0.009), tumor size (p=0.001) and AFP levels (p<0.001). Besides, significant correlation was detected between RASSF1A promoter hypermethylation and lymph nodes metastasis (p=0.045).The results of Kaplan-Meier estimates of survival suggested that LINE-1 hypomethylation was highly associated with poor survival of patients (disease-free survival p=0.002, overall survival p=0.0123). More importantly, co-evaluation of LINE-1 hypomethylation and RASSF1A promoter hypermethylation was found to be significantly correlated to early recurrence and poor prognosis (disease-free survival p=0.0001, overall survival p=0.05) in patients after curative resection.In conclusion, our study showed that the combined examination of LINE-1 hypomethylation and RASSF1A promoter hypermethylation was effective in predicting early recurrence of HCC after curative resection. Patients with dual positivity of LINE-1 hypomethylation and RASSF1A promoter hypermethylation should be supplied with more intensive care and close follow-up after they undergo tumor resection.

Velocity vector imaging for the assessment of segmental ventricular function in children with a single right ventricle after cavopulmonary anastomosis

OBJECTIVE

Ventricular function assessment is very important for the treatment and prognostic classification of children with a single right ventricle (SRV) after cavopulmonary anastomosis (CPA). However, unusual ventricular shapes can result in inaccurate measurements. The aim of this study was to evaluate velocity vector imaging (VVI) for assessing segmental ventricular function in children with SRV after CPA.

METHODS

Twenty-one children with SRV after CPA and 21 age- and sex-matched children with normal biventricular anatomy and function were included. The longitudinal velocity, displacement, strain and strain rate were measured in the two groups in six segments by VVI. The velocity, displacement, strain and strain rate of the SRVs were compared with max(dp/dt) measured during simultaneous cardiac catheterization in the SRV subjects.

RESULTS

The control group consisted of 13 males and 8 females (69% males) with a mean age of 6.7 ± 3.5 years and mean weight of 20.5 ± 6.5 kg, and the study group consisted of 13 males and 8 females with a mean age 6.7 ± 3.7 years and mean weight of 20.6 ± 6.8 kg. Age, weight and sex distribution were similar between the groups (all, p > .05). Strain and strain rate values in all six segments were significantly lower in the study group than in the control group (all, p < .05). The max(dp/dt) of the SRV was 522.84 ± 158.32 mmHg/s, and the strain rate of the basal segment at the rudimentary chamber correlated best with max(dp/dt) (r = 0.74, p < .01).

CONCLUSIONS

Segmental ventricular dysfunction was present in children with SRV after CPA, and it could be assessed using VVI.

Predicting hepatocellular carcinoma development for cirrhosis patients via methylation detection of heparocarcinogenesis-related genes

Background: Most hepatocellular carcinoma (HCC) patients have undergone a progression from chronic hepatitis, then liver cirrhosis (LC), and finally to carcinoma. The objective of this study was to elucidate risk factors to predict HCC development for cirrhosis patients. Methods: Multiple methylated specific PCR (MSP) was applied to determine methylation status of heparocarcinogenesis-related genes in 396 tissue and plasma specimens and multivariate cox model was used to analyze the relationship between risk variables and HCC development among cirrhosis patients, followed up in a median period of 30 months. Results: Among 105 LC cases, HCC incidence rate at 30 months was 30.48% (32/105), which were statistically associated with patients' age and aberrant methylation of p16, SFRP, and LINE1 (p<0.05). Receiver operating characteristic (ROC) curve showed the overall predictive accuracy reached the highest (90.7%) if the four risk variables were concurrent to predict HCC development. Moreover, along with the growth of age from 0-40, 40-55, to 55-70 years or the increased number of aberrantly-methylated gene from 0-1 to 2-3, the HCC incidence rate of cirrhosis patients rised from 10.00%, 12.28% to 82.14% and 17.44% to 89.47%, separately. Thus, based on combined analysis with diverse age and number of aberrantly-methylated gene, 105 cases were divided into five groups and computed their respective HCC incidecne rate to categorize them into different risk groups. Of note, A significant lifting of HCC incidence rate in the high-risk group (40-55 years coupled with 2-3 aberrantly-methylated genes, 55-70 years coupled with 0-1 aberrantly-methylated gene, 55-70 years coupled with 2-3 aberrantly-methylated genes; n=33) was observed compared with the low-risk group (0-40 years coupled with 0-1 aberrantly-methylated gene, 40-55 years coupled with 0-1 aberrantly-methylated gene; (n=72) (p<0.01). Conclusions: Ultimately, high-risk cirrhosis patients with 55-over years or 2-3 aberrantly-methylated genes should be paid more attention to be regularly screened with HCC development.

Application of multiplex methylated-specific PCR with capillary electrophoresis to explore prognostic value of TSGs hypermethylation for hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is a malignant tumor that severely threatens human health. To date, early detection for HCC patients is particularly significant due to their poor survival rates even after liver resection.

METHODS

Therefore, an efficient and sensitive detection method for monitoring liver cancer, multiplex methylation-specific PCR (MSP) coupled with capillary electrophoresis, is developed.

RESULTS

Simulations demonstrated that the methylation status of RASSF1A, p16, SFRP1, and ELF could be detected even when DNA equaled or exceeded 12.5 ng simultaneously. Also, its accuracy for methylation detection outweighed polyacrylamide gel electrophoresis (87.5%) and agarose electrophoresis (84.3%), reaching 92.1%. Subsequently, we implemented multiplex MSP with capillary electrophoresis to investigate methylation status of the four tumor suppressor genes in tissue specimens and explore the prognostic value for HCC patients. As the data suggested, multivariate cox regression analysis revealed that the recurrence-free survival of 46 patients was greatly associated with portal vein tumor thrombus (PVTT) and p16 methylation and receiver operating characteristic (ROC) curves demonstrated that the predictive range of portal vein tumor thrombus (PVTT) combined with p16 hypermethylation was more sensitive than that of either PVTT or p16 hypermethylation alone with regard to disease recurrence in patients with HCC, which could be testified as a valuable biomarker in Clinical application.

CONCLUSION

Multiplex MSP coupled with capillary electrophoresis has an excellent prospect of clinical application for monitoring early liver cancer and screening valuable biomarkers for prognosis of HCC patients.

Diagnostic Accuracy of Three-dimensional Turbo Field Echo Magnetic Resonance Imaging Sequence in Pediatric Tracheobronchial Anomalies with Congenital Heart Disease

Tracheobronchial anomalies are common in congenital heart disease (CHD), including tracheobronchial stenosis, tracheal bronchus, cardiac bronchus, and bronchial isomerism, which can cause varying degrees of respiratory illness. It is necessary to assess tracheobronchial anomalies and make a preoperative airway evaluation. Multi-slice computed tomography (MSCT) and cardiac magnetic resonance imaging (MRI) are the most effective noninvasive modalities for the diagnosis of CHD and the associated tracheobronchial anomalies. However, MSCT remains an ionizing procedure despite using low dose protocols. The aim of this study was to evaluate diagnostic accuracy of tracheobronchial anomalies in patients with CHD using three-dimensional turbo field echo(3D-TFE) magnetic resonance imaging sequence for preoperative airway evaluation. The results indicated that 3D-TFE provided better image quality as compared to that of 3D-balanced turbo field echo (3D-bTFE), and it can clearly demonstrated the tracheobronchial tree and tracheobronchial anomalies in CHD. This study confirms the clinical value of 3D-TFE in diagnosing tracheobronchial anomalies and supply helpful tracheobronchial information for preoperative strategies and postoperative follow-up.

Evaluation of the anatomic and hemodynamic abnormalities in tricuspid atresia before and after surgery using computational fluid dynamics

Analysis of hemodynamics inside tricuspid atresia (TA) chamber is essential to the understanding of TA for optimal treatment. In this study, we introduced a combined computational fluid dynamics (CFD) to simulate blood flow in the left ventricle (LV) to study the diastolic flow changes in TA.Real-time 3-dimentional echocardiography loops (ECHO) were acquired in normal control group, in TA patients before surgery (pre-op group) and after surgery (post-op group). ECHO loops were reconstructed and simulated by CFD, the geometric, volumetric changes, and vortices in the LV were studies and compare among 3 groups.Compared with the control group, pre-op TA patients demonstrated significant LV remodeling, manifesting with smaller LV length, larger diameter, width and spherical index, as well as lager volumes; post-op TA group showed revisions in values of both geometric and volumetric measurements. CDF also demonstrated the abnormality of vortices in the pre-op TA patients and the alteration of existence and measurements of vortex in postoperation group.Echo-based CFD modeling can show the abnormality of TA in both LV geometric, volumetric measurements and intracardiac vortices; and CFD is capable to demonstrate the alterations of LV after Fontan and Glenn surgical procedure.

Migration of Macrophage-Like Cells within Encapsulated Islets of Langerhans Maintained in Tissue Culture

Islets of Langerhans isolated from the pancreas and encapsulated in alginate-polylysine-alginate microspheres can potentially serve as a self-regulating supply of insulin in response to glucose loads. A longitudinal ultrastructural and immunohistochemical study of encapsulated rat islets cultured in CMRL-1969 media at a constant glucose concentration of 5.5 mmol/L (100 mg%) allowed several observations. First, acinar cells, which remain attached to isolated islets, disappeared within 1 wk in tissue culture. Damaged endocrine cells also disappeared at this time. Phagocytic cells having ultrastructural features suggesting that they are macrophages emerged from the islets within about a week and ingested portions of the inner layer of capsule polymer. These macrophage-like cells retained these polymers until their death which occurred at around 1-2 mo after isolation; at no time did we observe phagocytic cells actually breaching the microsphere capsules. Beta cells remained well-granulated over 90 days of culture but accumulated lipofuscin-like residual bodies. Under these conditions, these bodies began to accumulate appreciably after about one week in culture.

A prospective evaluation of contrast and radiation dose and image quality in cardiac CT in children with complex congenital heart disease using low-concentration iodinated contrast agent and low tube voltage and current

OBJECTIVE

To the assess image quality, contrast dose and radiation dose in cardiac CT in children with congenital heart disease (CHD) using low-concentration iodinated contrast agent and low tube voltage and current in comparison with standard dose protocol.

METHODS

110 patients with CHD were randomized to 1 of the 2 scan protocols: Group A (n = 45) with 120 mA tube current and contrast agent of 270 mgI/ml in concentration (Visipaque^™; GE Healthcare Ireland, Co., Cork, UK); and Group B (n = 65) with the conventional 160 mA and 370 mgI/ml concentration contrast (Iopamiro^®; Shanghai Bracco Sine Pharmaceutical Corp Ltd, Shanghai, China). Both groups used 80 kVp tube voltage and were reconstructed with 70% adaptive statistical iterative reconstruction algorithm. The CT value and noise in aortic arch were measured and the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. A five-point scale was used to subjectively evaluate image quality. Contrast and radiation dose were recorded.

RESULTS

There was no difference in age and weight between the two groups (all p > 0.05). The iodine load and radiation dose in Group A were statistically lower (3976 ± 747 mgI vs 5763 ± 1018 mgI in iodine load and 0.60 ± 0.08 mSv vs 0.77 ± 0.10 mSv in effective dose; p < 0.001). However, image noise, CT value, CNR, SNR and subjective image quality for the two groups were similar (all p > 0.05), and with good agreement between the two observers. Comparing the surgery results, the diagnostic accuracy for extracardiac and intracardiac defects for Group A was 96% and 92%, respectively, while the corresponding numbers for Group B were 95% and 93%.

CONCLUSION

Compared with the standard dose protocol, the use of low tube voltage (80 kVp), low tube current (120 mA) and low-concentration iodinated contrast agent (270 mgI/ml) enables a reduction of 30% in iodine load and 22% in radiation dose while maintaining compatible image quality and diagnostic accuracy. Advances in knowledge: The new cardiac CT scanning protocol can largely reduce the adverse effects of radiation and contrast media to children. Meanwhile, it also can be used effectively to examine complex CHD.

[The Evaluation Value of Methylation Status of CpG Island of SFRP1 and LINE1 Gene Promoter Area in the Prognosis of Hepatocellular Carcinoma.]

OBJECTIVES

To investigate the relationship between aberrant promoter CpG islands methylation status of secreted frizzled related protein 1 (SFRP1) and long intersper sed nuclear element 1 (LINE1) gene and clinicopathologic parameters to determine their prognosis value for hepatocellular carcinoma (HCC).

METHODS

105 cases of HCC and 50 cases of normal people plasma were collected,and then the promoter hypermethylation status of SFRP1 and hypormethylation status of LINE1 were examined by methylation specific PCR (MSP); The relationship between SFRP1/LINE1 methylation status and patients' clinicopathologic factors was analyzed;The association between SFRP1/LINE1 methylation status and disease-free survival and overall survival was analyzed by Kaplan-Meier curves,the log-rank test,and multivariate Cox regression.

RESULTS

SFRP1 gene promoter CpG islands hypermethylation and LINE1 gene promoter CpG islands hypomethylation were found in 59.05% (62/105) and 66.67% (70/105) of 105 cancerous plasma cases,repectively,SFRP1 hypermethylation status and LINE1 hypomethylation status in plasma of HCC account for 43.81%(62/105) and no positive methylation cases were detected in normal cases;The hypermethylation status of SFRP1 and hypomethylation status of LINE1 gene were related with HBsAg and α-fetoprotein (AFP) level;There was statistically significant difference between CpG islands hypermethylation of two genes and disease-free survival rate and overall survival rate;The group patients with SFRP1 hypermethylation positive and LINE1 hypomethylation positive demonstrated the worst prognosis while the group with SFRP1 hypermethylation negative and LINE1 hypomethylation negative had the best prognosis.

CONCLUSIONS

The promoter methylation of SFRP1 and LINE1 is correlated with the occurrence and development of HCC.SFRP1 and LINE1 might be potential and reliable biomarkers for predicting prognosis in HCC patients.

[miR-124 regulates radiosensitivity of colorectal cancer cells by targeting PRRX1]

OBJECTIVE

To detect the expression of miR-124 in colorectal carcinoma (CRC) cells and tissue specimens and analyze its association with the radiosensitivity of the cells.

METHODS

The expression of miR-124 in CRC cell lines and tissues were detected using qRT-PCR. The effect of miR-124 in modulating cell radiosensitivity was assessed in CRC cells with miRNA-124 overexpression and miRNA-124 knockdown, and bioinformatics prediction and dual luciferase reporter system were employed to identify the direct target of miR-124.

RESULTS

s miR-124 expression was down-regulated in CRC cell lines and tissues. CRC cells over-expressing miR-124 showed an obviously enhanced radiosensitivity, whereas miR-124 knockdown resulted in a reduced radiosensitivity of the cells. Bioinformatics prediction and dual luciferase reporter system verified PRRX1 as a direct target of miR-124, which regulated the radiosensitivity of CRC cells by directly inhibiting PRRX1.

CONCLUSION

miR-124 can enhance the radiosensitivity of CRC cells by directly targeting PRRX1, which provides a target for improving the therapeutic effect of radiotherapy of CRC.

Multi-slice computed tomography assessment of bronchial compression with absent pulmonary valve

BACKGROUND

Absent pulmonary valve is a rare cardiovascular anomaly that can result in profound tracheobronchial compression.

OBJECTIVE

To demonstrate the advantage of multi-slice CT in diagnosing tracheobronchial compression, its severity as related to the adjacent dilated pulmonary arteries, and associated lung and cardiac lesions.

MATERIALS AND METHODS

We included children with absent pulmonary valve who were reviewed by multi-slice CT during a 17-year period. The number and locations of stenoses and lung lesions were noted and the severity of stenosis was categorized. The diameter of the pulmonary artery was measured and associated cardiac defects were demonstrated.

RESULTS

Thirty-one children (14 girls and 17 boys) were included. Of these, 29 had ventricular septal defect and 2 had an intact ventricular septum. Twenty-nine children (94%) had tracheobronchial compression, judged to be mild in nine children (31%), moderate in 10 (34%) and severe in 10 (34%). The different locations of the stenosis (carina, main bronchi, lobar and segmental bronchi) were observed. And the number and location of lung lesions demonstrated that the right middle and left upper and lower lobes were often affected. The diameter of the pulmonary artery in these children was well above normal published values, and Spearman rank correlation analysis showed a correlation between the size of the pulmonary artery and the severity of the tracheobronchial stenosis. Nineteen children (61%) underwent surgery and 4 of these children had a multi-slice CT post-operative follow-up study.

CONCLUSION

Absent pulmonary valve can cause significant morbidity and mortality in children. Multi-slice CT can accurately depict areas of tracheobronchial compression, associated lung lesions and cardiac defects, helping to direct the surgeon.

Results of a phase III clinical trial with an HBsAg-HBIG immunogenic complex therapeutic vaccine for chronic hepatitis B patients: experiences and findings

BACKGROUND & AIMS

Even though various experimental therapeutic approaches for chronic hepatitis B infection have been reported, few of them have been verified by clinical trials. We have developed an antigen-antibody (HBsAg-HBIG) immunogenic complex therapeutic vaccine candidate with alum as adjuvant (YIC), aimed at breaking immune tolerance to HBV by modulating viral antigen processing and presentation. A double-blind, placebo-controlled, phase II B clinical trial of YIC has been reported previously, and herein we present the results of the phase III clinical trial of 450 patients.

METHODS

Twelve doses of either YIC or alum alone as placebo were administered randomly to 450 CHB patients and they were followed for 24weeks after the completion of immunization. The primary end point was HBeAg seroconversion, and the secondary end points were decrease in viral load, improvement of liver function, and histology.

RESULTS

In contrast to the previous phase II B trial using six doses of YIC and alum as placebo, six more injections of YIC or alum resulted in a decrease of the HBeAg seroconversion rate from 21.8% to 14.0% in the YIC group, but an increase from 9% to 21.9% in the alum group. Decrease in serum HBV DNA and normalization of liver function were similar in both groups (p>0.05).

CONCLUSIONS

Overstimulation with YIC did not increase but decreased its efficacy due to immune fatigue in hosts. An appropriate immunization protocol should be explored and is crucial for therapeutic vaccination. Multiple injections of alum alone could have stimulated potent inflammatory and innate immune responses contributing to its therapeutic efficacy, and needs further investigation.

Optimization of microencapsulation parameters: Semipermeable microcapsules as a bioartificial pancreas

An improved membrane has been developed for the microencapsulation of islets of Langerhans which protects these cells from the immune system. These requirements were accomplished through the optimization of important microencapsulation parameters and through the improved biocompatibility of a new alginate-poly-l-lysine (PLL)-alginate capsule membrane. Spherical and smooth microcapsules could be formed by utilizing a purer sodium alginate and by keeping the viscosity of the sodium alginate solution above 30 cps. The strength of the capsule membrane was enhanced by increasing the alginate-PLL reaction time as well as the PLL concentration. The permeability of the membrane [4 mum thick, 93% (w/w) water] was a function of the viscosity average molecular weight (Mv) of the PLL (Mv = 4000-4 x 10(5)) used in the encapsulation procedure. Microcapsules prepared with PLL with Mv = 1.7 x 10(4) were the least permeable, being impermeable to normal serum immunoglobulin, albumin, and haemoglobin. The microencapsulation procedure, by protecting transplanted tissue from the components of the immune system, has great clinical potential as a new form of treatment for diseases such as diabetes and liver disease.

Hrd1 facilitates tau degradation and promotes neuron survival

Intraneuronal accumulation of abnormal phosphorylated tau (p-tau) is a molecular pathology in many neurodegenerative tauopathies, including Alzheimer's disease (AD) and frontotemporal dementia with parkinsonism-linked to chromosome 17 (FTDP-17). However, the underlying mechanism remains unclear. Here, we showed an inverse relationship between endoplasmic reticulum membrane ubiquitin ligase (E3) Hrd1 expression and p-tau accumulation in the hippocampal neurons of AD, and proposed that Hrd1 may be a negative regulator of p-tau. This notion was further supported by in vitro study demonstrating that Hrd1 interacted with tau and promoted the degradation of total tau and p-tau as well. The degradation of tau depended on its Hrd1 E3 activity. Knockdown of endogenous Hrd1 with siRNA stabilized tau levels. In addition, inhibition of proteasome maintained tau level and increased Hrd1-mediated tau ubiquitination, suggesting the proteasome was involved in tau/p-tau degradation. Over-expression of Hrd1 significantly alleviated tau cytotoxicity and promoted cell survival. These results indicated that Hrd1 functions as an E3 targeting tau or abnormal p-tau for proteasome degradation. The study provides an important insight into the molecular mechanisms of human tauopathies.

Cytokine tumor necrosis factor alpha induces intestinal epithelial barrier dysfunction

BACKGROUND AND AIMS

Epithelial barrier dysfunction is involved in a number of diseases in the body. The mechanism is to be further understood. The present study aimed to investigate the role of one of the common microbial products, flagellin (FGN), in the induction of intestinal epithelial barrier dysfunction.

METHODS

We collected the colon epithelium specimens from 40 patients with ulcerative colitis (UC), 40 patients with Crohn's disease (CD) and 40 healthy volunteers. The expression of toll like receptors (TLR)5 of the specimens was assessed by RT-PCR and western blotting. The expression of tumor necrosis factor alpha (TNFα) and its role in compromising the barrier function in the intestinal epithelial cells, T84 cells, were observed by a cell culture model.

RESULTS

The results showed that the expression of TLR5 was observed in the colon epithelium of healthy subjects that was increased in UC patients and further increased in CD patients. Treating T84 cells with FGN increased the expression of TNFα in the cells that caused the T84 cell apoptosis as well as compromised the T84 monolayer barrier function, which could be prevented by knocking down the gene of TNFα in T84 cells.

CONCLUSIONS

We conclude that the human colon epithelial cells express detectable TLR5 that is increased in patients with CD and UC. The exposure to FGN can increase the expression of TNFα that further compromises the intestinal epithelial barrier function.

A functional variant in microRNA-196a2 is associated with susceptibility of colorectal cancer in a Chinese population

BACKGROUND AND AIMS

MicroRNAs (miRNA) can act as oncogenes or tumor suppressors. Polymorphisms present in pri-, pre- and mature miRNAs can potentially modulate the expression of hundreds of genes, broadly affecting miRNA function. Notably, the rs11614913 SNP in miR-196a2 has been implicated in carcinogenesis, but its association with colorectal cancer (CRC) remains unexplored. We performed a case-control study to investigate the genetic association between this functional SNP and CRC susceptibility and progression.

METHODS

We genotyped the rs11614913 SNP in 252 CRC patients and 543 healthy controls by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). In addition, we examined miR-196a expression level in colorectal cancer tissues (n = 50) obtained from the studied CRC patients.

RESULTS

Frequency of the CC genotype was higher in CRC patients than controls, implying that the subjects with the CC genotype or C allele containing genotypes (CT and CC) have a higher risk of CRC. However, no significant association between this polymorphism and CRC progression was observed. Expression analysis revealed that rs11614913 CC or carrying at least one C allele was associated with a significantly increased level of mature miR-196a (p = 0.010 or = 0.022).

CONCLUSIONS

The present study provides the first evidence that miR-196a2 polymorphism may contribute to CRC susceptibility in a Chinese population through modulating mature miR-196a expression.

Delayed onset of tricuspid valve flow in repaired tetralogy of Fallot: an additional mechanism of diastolic dysfunction and interventricular dyssynchrony

BACKGROUND

Diastolic dysfunction of the right ventricle (RV) is common after repair of tetralogy of Fallot. While restrictive physiology in late diastole has been well known, dysfunction in early diastole has not been described. The present study sought to assess the prevalence and mechanism of early diastolic dysfunction of the RV defined as delayed onset of the tricuspid valve (TV) flow after TOF repair.

METHODS

The study population consisted of 31 children with repaired TOF (mean age ± SD, 12.3 ± 4.1 years) who underwent postoperative cardiovascular magnetic resonance (CMR). The CMR protocol included simultaneous phase-contrast velocity mapping of the atrioventricular valves, which enabled direct comparison of the timing and patterns of tricuspid (TV) and mitral (MV) valve flow. The TV flow was defined to have delayed onset when its onset was > 20 ms later than the onset of the MV flow. The TV and MV flow from 14 normal children was used for comparison. The CMR results were correlated with the findings on echocardiography and electrocardiography.

RESULT

Delayed onset of the TV flow was observed in 16/31 patients and in none of the controls. The mean delay time was 64.81 ± 27.07 ms (8.7 ± 3.2% of R-R interval). The delay time correlated with the differences in duration of the TV and MV flow (55.94 ± 32.88 ms) (r = 0.90, p < 0.001). Delayed onset was associated with prolongation of the RV ejection time in 9 and delayed onset and cessation of the pulmonary arterial flow in 4. Delayed onset was not associated with timing changes in the pulmonary artery in 3. The patients with delayed onset showed reduced RV ejection fraction (p = 0.01). However, the two groups did not show significant differences in TV E/A ratio, ventricular end-diastolic volumes, left ventricular ejection fraction, pulmonary regurgitant fraction, heart rate, PR interval and QRS duration.

CONCLUSIONS

Early diastolic dysfunction with delayed onset of TV flow is common after TOF repair, and is associated with reduced RV ejection fraction. It is a further manifestation of interventricular dyssynchrony and represent an additional mechanism of ventricular diastolic dysfunction.

Pharmacological inhibition of AKT sensitizes MCF-7 human breast cancer-initiating cells to radiation

BACKGROUND

Caner-initiating cells (CICs or cancer stem cells) have been shown both experimentally and clinically to be resistant to radiation. The mechanism underlying radioresistance remains unclear.

METHODS

In the present study, we screened 51 genes which are potentially important in mediating radioresistance of breast CICs.

RESULTS

The expression of AKT1 and AKT2 at protein and mRNA levels was dramatically increased among the screened genes by 8 Gy radiation treatment in MCF-7 mammosphere cells (predominantly CD24(-/low)/CD44(+) CICs), but not in the bulk population of MCF-7 cells (predominantly CD24(+)/CD44(+)). Using apoptosis and clonogenic survival assays, we found pharmacological inhibition of AKT with selective inhibitors of AKT sensitized MCF-7 mammosphere cells, but not MCF-7 monolayer cells to radiation.

CONCLUSION

The present findings suggest that treatment with AKT inhibitors prior to ionizing radiation treatment may be a potential benefit to patients with breast cancer, in particular to eradiate breast CICs.

STAT1 promotes radioresistance of CD44(+)/CD24(-/low) cells in breast cancer

Breast cancer-initiating cells are a relatively radioresistant subpopulation of breast cancer cells. However, the mechanism of this radioresistance is still unclear. This study aimed to investigate the effect of radiation on the levels of signal transducer and activator of transcription 1 (STAT1) in mammospheres of cancer-initiating cells and monolayer cultures of MCF-7 cells. We isolated CD44(+)/CD24(-/low) cancer-initiating cells from MCF-7 cells and propagated them as mammospheres. Next we used realtime quantitative reverse-transcriptase polymerase chain reaction to examine the mRNA level of STAT1 in mammospheres of breast cancer-initiating cells and monolayer cultures of MCF-7 cells. The apoptosis rate and surviving fraction using clonogenic assays was observed after treating the cells with a STAT1 inhibitor. After irradiation, the STAT1 level in the mammospheres was higher than that in the monolayer cultures. STAT1 inhibitor treatment did not cause significant changes in the apoptosis rate and surviving fraction in the MCF-7 monolayer cultures. However, the inhibitor treatment caused significant differences in the apoptosis rate and surviving fraction in mammospheres. Our study provides the first evidence that STAT1 signaling contributes to radioresistance in breast cancer-initiating cells and reveals STAT1 as a promising target to reduce radioresistance and enhance the efficacy of radiotherapy for breast cancer.

[p35 and p25 expressions and Cdk5 kinase activity in primary cultured rat hippocampal neurons with X-ray exposure]

OBJECTIVE

To study the expressions of p35 and p25 and Cdk5 kinase activity in cultured rats hippocampal neurons following X-ray exposure to provide experimental evidence for prevention and treatment of radiation encephalopathy.

METHODS

The hippocampal neurons cultured for 12 days were subjected to a single-dose X-ray exposure of 30 Gy. Western blotting was used to detect the p35 and p25 protein levels, and the effect of pretreatment with roscovitine, a Cdk5 inhibitor, on the apoptosis of the hippocampal neurons following the exposure was examined with 4',6-diamidino-2-phenylindole (DAPI) staining.

RESULTS

The protein level of p35 increased significantly 3.5 and 4 h after the irradiation by 1.51-/+0.13 and 1.45-/+0.14 folds in comparison with the control level, respectively (P<0.01), and the p25 level increased significantly 6 h after irradiation by 1.62-/+0.28 folds (P<0.05). Nuclear condensation occurred in (24.8-/+3.97)% of the neurons 24 h after 30 Gy X-ray exposure, a rate significantly higher than that in the nonexposed cells [(1.82-/+1.08)%, P<0.01) and that in roscovitine-pretreated neurons [(7.74-/+2.27)%, P<0.01).

CONCLUSION

X-ray exposure activates Cdk5 by increasing the p35 and p25 expressions in rat hippocampal neurons, and inhibition of Cdk5 activity with roscovitine can significantly protect the neurons from apoptosis.

Rna interference of annexin II gene in PC3 cells by using small interference RNA synthesized with in vitro transcription

OBJECTIVE

To silence annexin II gene expression by using small interference RNA (siRNA) in prostate cancer cell line PC3.

METHODS

For in vitro transcription, four sequences of 29-nucleotide DNA template oligonucleotides were designed, and one pair of the sequences were complementary to annexin II gene. The other pair was negative control. The 8 nucleotides at the 3' end of each oligonucleotide were complementary to the T7 Promoter Primer. The sense and antisense siRNA templates were transcribed by T7 RNA polymerase and the resulting RNA transcripts were hybridized to create dsRNA. The siRNA was transfected into prostate cancer cell PC3. For assaying the efficiency of siRNA, confocal microscopy, Northern blotting, and Western blotting were employed to examine the expression of annexin II protein and its mRNA. 3H thymidine was used to measure DNA synthesis.

RESULTS

The siRNA sequence specific to annexin II gene was capable of inhibiting the expression of annexin II protein and its mRNA. And cellular DNA synthesis was significantly reduced in siRNA transfected cells.

CONCLUSIONS

The protocol for the synthesis of siRNA by T7 RNA polymerase is feasible. Annexin II might be involved in DNA synthesis.

[A preliminary study on the mechanism of neurotoxicity of MDMA--oxidative stress harm]

OBJECTIVE

Establishing a long-term neurotoxic model to explore the mechanism of neurotoxicity of 3,4-methylenedioxymethamphetamine (MDMA) and the putative protection conferred by Vit C against oxidative stress harm.

METHODS

Male Wistar rats were randomly assigned to control group (A) and MDMA treatment groups(B, C, D, E). Rats of group B were given MDMA 20 mg/kg; groups C, D, E were given Vit C 250 mg/kg 30 min before administration of MDMA (Vit C 30 min group) and 3 h (Vit C 3 h group) and 5 h (VitC 5 h group) after administration of MDMA, respectively. Rats of control group were treated with the same volume of saline. Concentrations of ATP and ADP in brain cortex and 5-HT in hippocampus and occipital cortex were measured by high perfor-mance liquid chromatography; the expression of SERT mRNA was detected by in situ hybridization; and the expression of protein GFAP was detected by immunohisto-chemistry.

RESULTS

hours after MDMA treatment, the concentration of ATP in brain cortex was lessened, compared with control (P <0.05). On the 7th day after MDMA treatment, the concentration of 5-HT in rat hippocampus and occipital cortex was decreased, compared with control (P<0.05). The expression of SERT mRNA in hippocampus was decreased, whereas the expression of GFAP in brain tissue was increased (P<0.05). The adminstration of Vit C 30 min before MDMA treatment and 3 h after MDMA treatment did not curb the decrease of ATP, 5-HT and the expression of SERT mRNA, but Vit C administrated 5 h after MDMA treatment could curb the decrease of ATP and the functional markers of 5-HT. And Vit C given at three time points did downregulate the GFAP expression.

CONCLUSION

MDMA could deplete the direct energetic substance ATP. MDMA could exert neurotoxic effect on 5-HT system. Vit C given 5 h after MDMA administration could provide neuroprotection for ATP and 5-HT system.

MRI diagnosis of isolated origin of the left subclavian artery from the left pulmonary artery

Right aortic arch with isolation of the left subclavian artery is a rare disorder. In this entity, the left subclavian artery has its origin from the pulmonary artery via the ductus arteriosus. We report an infant with an unbalanced atrioventricular septal defect, right aortic arch, bilateral ductus arteriosi and an isolated left subclavian artery. This infant also had chromosome 22q11 deletion. The origin and course of the isolated subclavian artery were well-demonstrated using contrast-enhanced 3-D magnetic resonance angiography. This non-invasive diagnostic modality can accurately reveal detailed mediastinal vascular anatomy in a young infant and allows diagnosis of aberrant vascular connections.

[Correlation of protein kinase C isoform expression with multidrug resistance in KBV200 cells]

OBJECTIVE

To investigate the association of protein kinase C (PKC) isoforms and multidrug resistance (MDR) mechanism in KBV200 cells.

METHODS

Western blotting was utilized to examine the expression and subcellular distribution of PKC isoforms were measured in KBV200 cells with MDR and drug-sensitive KB cells, and the fluorescence intensity of PKC isoforms was detected by flow cytometry (FCM).

RESULTS

KBV200 cells possessed higher PKC activities, with increased percentage of membrane fraction. As compared with parental KB cells, the expression of PKCalpha was significantly increased in KBV200 cells, while PKCbeta and epsilon expressions remained unchanged, and PKCgamma and zeta failed to be detected. Fluorescence intensity of PKCalpha in KBV200 cells was increased.

CONCLUSION

PKC might contribute to MDR phenotype in KBV200 cells, and of the isoforms so far detected, PKCalpha might play an important role in MDR phenotype.

[Correlation of protein kinase C activity and its subcellular distrubution with multidrug resistance in KVB200 cells]

OBJECTIVE

To investigate the relationship between protein kinase C (PKC) and multidrug resistance (MDR) in cancer cell line KBV200.

METHODS

MTT assay was used to evaluate the IC50 of vincristine (VCR) and adriamycin (ADR) in KB cell line and its VCR-resistant derivative KBV200 cells. PKC activities in the 2 cell lines were assayed by measuring the incorporation of (32)P from [gamma-(32)P] ATP into the peptide substrates.

RESULTS

The IC50 values of VCR and ADR in KBV200 cells was 64.03 and 18.8 folds greater than those in KB cells. PKC activities of the membrane and cytosol fraction in KBV200 cells were increased compared with that in KB cells, with the total PKC activity 1.12-fold higher. Phorbol-12-myristate-13 -acetate increased PKC activity of the membrane fraction and IC50 values of KBV200 cells, while staurosporine worked to the opposite effects.

CONCLUSION

PKC may contribute to MDR mechanism in KBV200 cells.

Members of the Kv1 and Kv2 voltage-dependent K(+) channel families regulate insulin secretion

In pancreatic beta-cells, voltage-dependent K(+) (Kv) channels are potential mediators of repolarization, closure of Ca(2+) channels, and limitation of insulin secretion. The specific Kv channels expressed in beta-cells and their contribution to the delayed rectifier current and regulation of insulin secretion in these cells are unclear. High-level protein expression and mRNA transcripts for Kv1.4, 1.6, and 2.1 were detected in rat islets and insulinoma cells. Inhibition of these channels with tetraethylammonium decreased I(DR) by approximately 85% and enhanced glucose-stimulated insulin secretion by 2- to 4-fold. Adenovirus-mediated expression of a C-terminal truncated Kv2.1 subunit, specifically eliminating Kv2 family currents, reduced delayed rectifier currents in these cells by 60-70% and enhanced glucose-stimulated insulin secretion from rat islets by 60%. Expression of a C-terminal truncated Kv1.4 subunit, abolishing Kv1 channel family currents, reduced delayed rectifier currents by approximately 25% and enhanced glucose-stimulated insulin secretion from rat islets by 40%. This study establishes that Kv2 and 1 channel homologs mediate the majority of repolarizing delayed rectifier current in rat beta-cells and that antagonism of Kv2.1 may prove to be a novel glucose-dependent therapeutic treatment for type 2 diabetes.

Microencapsulated bovine chromaffin cell xenografts into hemiparkinsonian rats: a drug-induced rotational behavior and histological changes analysis

Bovine chromaffin cells were microencapsulated within alginate-polylysine-alginate (APA) membranes. Microencapsulated bovine chromaffin cells as well as unencapsulated cells and empty microcapsules were grafted into the brain of hemiparkinsonian rats with 6-hydroxydopamine (6-OHDA) lesions. Apomorphine-induced rotational behavior of the host animals and the survival of the grafted chromaffin cells were examined after transplantation. The animals receiving microencapsulated bovine chromaffin cells showed a significant decrease (17.6--35.6%) in apomorphine-induced rotation 1 week postimplantation that remained stable for the 10 month test period. Fluorescent histochemistry further revealed that microencapsulation increased the chromaffin cell survival with only a minimum host reaction for up to 10 months posttransplantation while the survival of free, unencapsulated chromaffin cells was only modest and was accompanied by a large inflammatory response. The reduction of apomorphine-induced rotations was correlated with the survival of bovine chromaffin cells in the host brain. The data indicate that encapsulation of bovine chromaffin cells in APA membranes reduces the host immune response to the xenograft and prolongs the viability of the grafted cells.

Xenotransplantation of microencapsulated bovine chromaffin cells into hemiparkinsonian monkeys

This study examines the effects of xenografts of microencapsulated bovine chromaffin cells (BCCs) on the rotational behavior of hemiparkinsonian monkey recipients. In addition, it determines the content of monoamine neurotransmitters and their major metabolites in the neostriatum in hemiparkinsonian monkeys. The hemiparkinsonian model in monkeys was induced by a unilateral intracarotid injection of methyl-phenyl-tetrahydropyridine (MPTP). Unencapsulated BCCs, BCCs microencapsulated in alginate-polylysine-alginate (ALA) membranes as well as empty microencapsules were grafted into the neostriatum of the hemiparkinsonian monkeys. Following the transplantation the hemiparkinsonian symptoms subsided and the number of rotations induced by apomorphine decreased for up to nine months in the group of recipients grafted with microencapsulated BCCs, while only a temporary improvement (one month) was detected in the recipients of the unencapsulated BCCs. No change was observed in the recipients of empty microencapsules. Dopamine and its metabolites were found considerably depleted in the MPTP-lesioned side versus the unlesioned side of the neostriatum in the hemiparkinsonian monkeys(P<0.05).

In pursuit of perfection: a primary care physician's guide to body dysmorphic disorder

Body dysmorphic disorder is an under-recognized chronic problem that is defined as an excessive preoccupation with an imagined or a minor defect of a localized facial feature or body part, resulting in decreased social, academic and occupational functioning. Patients who have body dysmorphic disorder are preoccupied with an ideal body image and view themselves as ugly or misshapen. Comorbid psychiatric disorders may also be present in these patients. Body dysmorphic disorder is distinguished from eating disorders such as anorexia nervosa that encompass a preoccupation with overall body shape and weight. Psychosocial and neurochemical factors, specifically serotonin dysfunction, are postulated etiologies. Treatment approaches include cognitive-behavioral psychotherapy and psychotropic medication. To relieve the symptoms of body dysmorphic disorder, selective serotonin reuptake inhibitors, in higher dosages than those typically recommended for other psychiatric disorders, may be necessary. A trusting relationship between the patient and the family physician may encourage compliance with medical treatment and bridge the transition to psychiatric intervention.

Bioartificial pancreas: alternative supply of insulin-secreting cells

In this study, insulin secretion function of INS-1 cells immunoisolated in microcapsules was evaluated. Following encapsulation, the immunoisolated INS-1 cells continued to propagate and flourish within the microcapsules during the entire two-month in vitro incubation period. The insulin secretion from encapsulated INS-1 cells following seven days of in vitro culture increased from 1.6 +/- 0.2 ng/2h/10(6) cells in a glucose-free medium to 11.5 +/- 2.1 ng/2h/10(6) cells at 16.7 mM glucose. In vivo, transplants of 1.2 x 10(7) cells into each of six diabetic C57BL/6 mice resulted in the restoration of normoglycemia in all graft recipients for up to 60 days post transplantation. Most capsules recovered from two animals 30 days post transplantation were free of cell overgrowth and physically intact. Immunostaining for insulin of the cells within the recovered capsules clearly indicated the presence of insulin. The presented data demonstrate the potential use of an immunoisolated beta-cell line for the treatment of diabetes.

Up-regulation of hepatocyte growth factor receptor: an amplification and targeting mechanism for hepatocyte growth factor action in acute renal failure

BACKGROUND

Hepatocyte growth factor (HGF) and its c-met receptor comprise a signaling system that has been implicated in tissue repair and regeneration. HGF action is specifically targeted to the damaged organ following injury; however, the mechanism underlying this important targeting process remains to be elucidated. We reasoned that induction of c-met expression might be a critical factor in determining the site specificity of this receptor-ligand system. To test this hypothesis, we examined changes in activity of the HGF/c-met system in the folic acid model of acute tubular injury and repair.

METHODS

Tissue HGF and c-met mRNA levels were detected by RNase protection assay and Northern blot analysis following acute renal injury induced by a single injection of folic acid. HGF and c-met proteins were examined by a specific enzyme immunoassay and Western blotting, respectively. C-met expression and trans-activation were investigated by exposing renal epithelial mIMCD-3 cells to various cytokines in vitro.

RESULTS

Extremely rapid induction of renal HGF and c-met mRNA was observed beginning one hour following injection of folic acid. Circulating plasma HGF protein level rose dramatically (approximately 16-fold), peaking first at two hours and again at 24 hours following injection. Despite elevated HGF mRNA in the kidney, total kidney HGF protein actually decreased significantly at 24 hours following injury. On the other hand, both c-met mRNA and c-met protein were markedly increased in the kidney, where active renal tubule repair and regeneration take place. In vitro studies suggested that increased levels of HGF, as well as other cytokines, might account for enhanced c-met expression in renal tubular epithelial cells. Pretreatment of the cells with actinomycin D totally blocked c-met induction, suggesting that induced c-met expression occurs primarily at the transcriptional level. Using a cloned region of the c-met promoter coupled to a reporter gene, we demonstrated that HGF directly stimulated c-met promoter transactivation in renal epithelial cells.

CONCLUSION

These results suggest that local up-regulation of c-met transcription in the kidney is crucial to renal tubule repair and regeneration, not only because it increases overall activity of this receptor-ligand system, but also as a mechanism targeting HGF action specifically to renal epithelia.

Methods for the immunoisolation and transplantation of pancreatic cells

Although the administration of insulin by injection is clearly a life-saving intervention for patients devoid of β-cells, this approach falls short of the remarkable titration of insulin delivery and consequent control of glucose levels achieved by normal, healthy individuals. In the absence of the physiological control of the plasma glucose concentrations, the daily injection of insulin has not been able to prevent the common complications of the disease, namely nephropathy, retinopathy, and neuropathy, as well as vascular complications. This has been confirmed in the recent diabetes control and complications trial which has demonstrated that intensive treatment of patients with insulin-dependent diabetes mellitus (IDDM), with tight glycemic control close to the control range, effectively delays the onset, and slows the progression, of the various diabetic complications (1). Therefore, it becomes mandatory to develop methods, applicable early in the course of the disease, and in any type 1 diabetic patient, for obtaining perfect metabolic control without increasing the risk of severe hypoglycemia. Consequently, the transplantation of islet tissue, either as whole pancreas or as isolated islets, has been pursued, because these techniques can provide near-normal blood glucose control, and thus have the potential to prevent diabetic complications.

Evaluation of immunoisolated insulin-secreting beta TC6-F7 cells as a bioartificial pancreas

OBJECTIVE

To evaluate the growth and insulin secretion from microencapsulated beta TC6-F7 cells in vitro and to assess the in vivo function of microencapsulated cells transplanted in rats with steptozotocin (STZ)-induced diabetes.

METHOD

Alginate-poly-L-lysine encapsulated beta TC6-F7 cells were exposed to glucose, isobutylmethylxanthine (IBMX) and glucagon-like peptide I (7-36 amide) in a static in vitro challenge. In vivo, 2.5-3.5 x 10(7) encapsulated cells were implanted into diabetic rats. Graft function was evaluated by monitoring blood glucose concentrations and by an intraperitoneal glucose tolerance test.

RESULTS

The cell density (number of cells per capsule) of cultured microencapsulated beta TC6-F7 cells increased almost 35-fold over a 55 day observation period to reach a plateau of approximately 3500 cells/capsule. While insulin secretion per capsule remained unchanged over the first 21 days of culture, a 7-fold increase was observed during the last 14 days of the 55 day observation period. Intraperitoneal transplantation of 3.5 x 10(7) encapsulated cells into diabetic rats resulted, within 24 hours, in reversal of hyperglycemia for up to 60 days. Post-transplantation blood glucose concentrations varied between 2 and 4 mM. Glucose clearance rates evaluated by an intraperitoneal glucose tolerance test at 30 days post-transplantation resulted in a markedly flat glucose clearance curve with blood glucose never rising above 4 mM. The glucose challenge of microencapsulated cells recovered 30 days post-transplantation resulted in a 2-fold increase in insulin response at glucose concentrations greater than 5.5 mM as compared to glucose-free media. In addition, immunostaining of recovered grafted tissue for insulin, reveals a strong presence of the peptide within the cell population.

CONCLUSIONS

These data demonstrate the potential use of an immunoisolated beta-cell line for the treatment of diabetes.

Effect of hypoxic exposure on Na+/H+ antiport activity, isoform expression, and localization in endothelial cells

Little is known about the effects of prolonged hypoxic exposure on membrane ion transport activity. The Na+/H+ antiport is an ion transport site that regulates intracellular pH in mammalian cells. We determined the effect of prolonged hypoxic exposure on human pulmonary arterial endothelial cell antiport activity, gene expression, and localization. Monolayers were incubated under hypoxic or normoxic conditions for 72 h. Antiport activity was determined as the rate of recovery from intracellular acidosis. Antiport isoform identification and gene expression were determined with RT-PCR and Northern and Western blots. Antiport localization and F-actin cytoskeleton organization were defined with immunofluorescent staining. Prolonged hypoxic exposure decreased antiport activity, with no change in cell viability compared with normoxic control cells. One antiport isoform [Na+/H+ exchanger isoform (NHE) 1] that was localized to the basolateral cell surface was present in human pulmonary arterial endothelial cells. Hypoxic exposure had no effect on NHE1 mRNA transcript expression, but NHE1 protein expression was upregulated. Immunofluorescent staining demonstrated a significant alteration of the F-actin cytoskeleton after hypoxic exposure but no change in NHE1 localization. These results demonstrate that the decrease in NHE1 activity after prolonged hypoxic exposure is not related to altered gene expression. The change in NHE1 activity may have important consequences for vascular function.

Expression of Na+/H+ exchanger isoforms in inner segment of inner medullary collecting duct

Na+/H+ exchangers (NHE) play a critical role in many cellular and transport processes in the inner medullary collecting duct (IMCD). Morphologically, the IMCD is divided into the outer (IMCD1), middle (IMCD2), and inner (IMCD3) segments. The inner, IMCD3 segment contains only one cell type, the IMCD cell, which is distinct in ultrastructure and in function from the principal and intercalated cells that are present in other portions of the IMCD. NHEs constitute a gene family containing several isoforms (NHE1, NHE2, NHE3, NHE4 and NHE5) which possess distinct characteristics and serve specialized functions. To understand the molecular basis of NHE-related processes in the IMCD, it is critical to know the molecular identity of the NHEs in this tubule segment. The purpose of the present study was to identify the NHE isoforms present and their polar distribution in IMCD3. Applying the reverse transcription-polymerase chain reaction (RT-PCR) technique to IMCD3 (obtained from distal 50% of inner medulla) of mouse and rat kidneys, we found that NHE1, NHE2 and NHE4, but not NHE3 were expressed in both species. The polar localization of NHE in IMCD3 was examined in tubules isolated from rats and perfused in vitro with HEPES-buffered solutions under isotonic conditions. pHi was measured by BCECF fluorescence. Na+-dependent, amiloride-inhibitable pHi recovery from cell acidification (consistent with NHE) was detected in the basolateral, but not the apical, membrane of IMCD3. We conclude that NHE1, NHE2 and NHE4, but not NHE3, are present in both the mouse and rat IMCD3. Functionally, NHE is limited to the basolateral membrane. Additional studies are needed to determine the physiological roles and regulation of basolateral NHE isoforms in this tubule segment.

Constitutive expression of HGF modulates renal epithelial cell phenotype and induces c-met and fibronectin expression

Hepatocyte growth factor (HGF) is a potent renotropic factor that has been shown to play important roles in kidney development and recovery from acute renal injury. To examine the effects of HGF on renal tubular epithelium, we generated HGF-producing renal epithelial cells by stably transfecting mIMCD-3 and OK cells with an expression plasmid containing human HGF cDNA. Expression of HGF in the transfected cells was confirmed by detection of HGF mRNA by Northern blot analysis and detection of HGF secretion into the conditioned medium by ELISA. HGF-transfected cells exhibited fibroblast-like scattered morphology and increased cell motility. They formed branching tubules when grown in 3-D collagen gel. In addition, HGF-producing cells grew faster than their parental cells, but failed to form colonies in soft agar. These phenotypic changes were inhibited by a specific, neutralizing anti-HGF antibody. Interestingly, both c-met transcript and c-met protein were increased in HGF-transfected cells, suggesting that HGF amplifies its own action via stimulation of c-met expression. Autocrine expression of HGF and c-met in renal epithelial cells also stimulated fibronectin gene expression, which was totally blocked by incubation with a neutralizing anti-HGF but not a pan-specific anti-TGF-beta antibody, suggesting that it is independent of TGF-beta production. Our data demonstrate that HGF as a single factor stimulates renal epithelial cell proliferation, migration, differentiation, and extracellular matrix remodeling, making it uniquely suited to promote renal tubulogenesis during development, as well as to reconstitute tubular integrity following acute injury.

Genetic engineering of glucose-stimulated insulin secretion in Chinese hamster ovary cells

To engineer an a non-islet cell capable of glucose-stimulated insulin secretion, a chinese hamster ovary cell line (CHO) was transfected with a mammalian expression vector carrying the human insulin cDNA (pCB/hINS). More proinsulin than insulin was released daily by the stably transformed cell line (CHO-INS). Examination of acid-ethanol extracts confirmed that both insulin and proinsulin were stored. Immunohistochemical analysis of the cells also showed that (pro)insulin was stored. Unlike beta cells, CHO-INS cells did not secrete insulin in response to glucose. To investigate this lack of effect, we examined whether transfection of GLUT2 cDNA, which is ordinarily not expressed in CHO-INS cells, would confer glucose-stimulated insulin secretion. Consequently, we have demonstrated that glucose regulated insulin release occurs in the CHO-INS-GLUT2 cell line and that glucose potentiates the insulin secretory response to non-glucose secretagogues.

Hepatocyte growth factor protects renal epithelial cells from apoptotic cell death

Hepatocyte growth factor (HGF) is a pleiotropic factor that plays an essential role in renal tubular repair and regeneration following injury. Studies indicate that administration of exogenous HGF to animals stimulates renal epithelial cell DNA synthesis and accelerates recovery from acute renal failure (ARF). However, whether increased cell proliferation accounts for all of the beneficial effects of HGF in ARF is unknown. In this study, we demonstrate that HGF protects renal epithelial cells from undergoing apoptotic cell death. Treatment of renal epithelial mIMCD-3 cells with 25 microM cisplatin in the serum-free medium induced significant apoptosis, as assessed by fluorescent Dye H-33342 staining, TUNEL staining, light and electron microscopy, and DNA laddering analysis. However, constitutive expression of HGF by transfection in mIMCD-3 cells resulted in resistance to cisplatin-induced apoptotic death. The survival rate of HGF-producing C1 cells was more than 2-fold greater as compared to control, mIMCD-3 cells following treatment with 25 microM cisplatin for 2 days. These results suggest that HGF may not only activate tubular repair processes but also ameliorate the initial injury by protecting renal epithelial cells from undergoing apoptosis.

In vitro and in vivo evaluation of insulin-producing beta TC6-F7 cells in microcapsules

In the present study, the insulin secretory capacity of beta TC6-F7 cells in microcapsules was evaluated. The cell mass within capsules was found to expand in a three-dimensional fashion, in contrast to cells seeded on plates that grew as a monolayer. In in vitro studies, both free and encapsulated cells were found to secrete insulin in the absence of glucose, at 13.6 +/- 1.1 and 14.5 +/- 0.9 ng.10(6) cells-1.60 min-1, respectively, with the response rising to a maximum of 26.0 +/- 0.8 and 31 +/- 2.3 ng.10(6) cells-1.60 min-1 in the presence of 16.8 mM glucose. Encapsulated cells were able to produce Ca2+ responses in the presence of KCl (50 mM) and BAY K 8644 (100 microM). In in vivo studies, intraperitoneal transplantation of 3.0 x 10(6) microencapsulated cells into mice (n = 5) with streptozotocin-induced diabetes resulted in the restoration of normoglycemia up to 57 days. Insulin concentrations rose from 0.4 +/- 0.1 ng/ml before the graft administration to 2.2 +/- 0.8 ng/ml after the transplantation in the normoglycemic recipients. An oral glucose challenge in transplant recipients demonstrated a flat glucose response, suggesting extremely high glucose clearance rates. These data demonstrate the potential use of the immunoisolated beta-cell lines for the treatment of diabetes.

Expression of Cl-/HCO3- exchanger in the basolateral membrane of mouse medullary thick ascending limb

Although a basolateral Cl-/HCO3- exchanger (AE) has been implicated in the arginine vasopressin (AVP)-dependent hypertonic regulatory increase in the medullary thick ascending limb (MTAL), there are conflicting data regarding whether this exchanger is indeed present in this tubule segment. In this study, mouse MTAL was examined whether Cl-/HCO3- exchange activity was present in the basolateral membrane and whether mRNAs from the known AE genes are expressed. Cl-/HCO3- exchange activity was examined in isolated perfused MTAL tubules under isotonic conditions and in the absence of arginine vasopressin. 2',7'-Bis(2-carboxyethyl)-5(6)-carboxyfluorescein was used to monitor intracellular pH. Removal of basolateral Cl- induced reversible cell alkalization that was independent of external Na+ and completely inhibited by peritubular 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (200 microM). The rate and extent of cell alkalinization were significantly greater in the presence than absence of external CO2/HCO3-. A voltage clamp did not inhibit cell alkalinization induced by basolateral Cl- removal. Consistently, addition of basolateral Cl- induced reversible cell acidification in MTAL depleted of intracellular Cl-. Furthermore, mRNA encoding two members (AE2 and AE3) of the AE gene family were demonstrated in microdissected mouse MTAL tubules by reverse transcription-polymerase chain reaction. It is concluded that AE is present in the basolateral membrane of mouse MTAL.