Comparison of multichannel signal deconvolution algorithms in airborne LiDAR bathymetry based on wavelet transform.

Airborne LiDAR bathymetry offers low cost and high mobility, making it an ideal option for shallow-water measurements. However, due to differences in the measurement environment and the laser emission channel, the received waveform is difficult to extract using a single algorithm. The choice of a suitable waveform processing method is thus of extreme importance to guarantee the accuracy of the bathymetric retrieval. In this study, we use a wavelet-denoising method to denoise the received waveform and subsequently test four algorithms for denoised-waveform processing, namely, the Richardson-Lucy deconvolution (RLD), blind deconvolution (BD), Wiener filter deconvolution (WFD), and constrained least-squares filter deconvolution (RFD). The simulation and measured multichannel databases are used to evaluate the algorithms, with focus on improving their performance after data-denoising and their capability of extracting water depth. Results show that applying wavelet denoising before deconvolution improves the extraction accuracy. The four algorithms perform better for the shallow-water orthogonal polarization channel (PMT2) than for the shallow horizontal row polarization channel (PMT1). Of the four algorithms, RLD provides the best signal-detection rate, and RFD is the most robust; BD has low computational efficiency, and WFD performs poorly in deep water (< 25 m).

[Efficacy of early consecutive lumbar puncture treatment in aneurysmal subarachnoid hemorrhage after embolization].

OBJECTIVE: To summarize the significance of lumbar punctures in remedy for aneurysmal subarachnoid hemorrhage (aSAH) after embolization. METHODS: From December 2002 to September 2011, 43 cases of aSAH underwent aneurysm embolization at department of interventional radiology and vascular surgery, Peking University Third Hospital. After the embolization,consecutive lumbar punctures were undertaken everyday, by which we measured proper cerebrospinal fluid pressure and slow drainage of cerebrospinal fluid. In accordance with the lumbar puncture results we determined the control of blood pressure, dehydration and rehydration therapy procedures. RESULTS: Two patients died. Only one patient in the 41 cases of the survived patients developed cerebral vasospasm, cerebral infarction and obstructive hydrocephalus, but by ventriculo-peritoneal shunt, obstructive hydrocephalus was relieved. The remaining 39 patients recovered well. After the mean follow-up of (26.0±5.8) months, no new neurological symptoms were found. CONCLUSION: Early consecutive lumbar puncture treatment in ASH after embolization is significant.

[Histological character of intimal hyperplasia post jugular vein grafts and the protective effect of lovastatin].

OBJECTIVE: To investigate the characteristics of intimal hyperplasia and lovastatin's effects on canine jugular venous prosthesis bypass grafting. METHODS: In the study, 12 adult mistus dogs were randomly divided into 2 groups: lovastatin group and control group. All the dogs were performed with jugular venous prosthesis bypass grafting (ePTFE, 6 mm in diameter, and 5 cm in length). Four weeks later, all the 12 specimens were harvested. The patency and mural thrombus of grafts were evaluated. The characteristics of intimal hyperplasia were described and measured by HE staining and endothelial nitric oxide synthase (eNOs) immunohistochemical method. The differences between the two groups were compared. RESULTS: Four weeks later, 3 grafts with complete occlusion were found in the two groups separately. Apparent intimal hyperplasia was observed in all the grafts. The neointima of proximal and distal part in lovastatin group were thinner than in control group respectively (proximal P=0.045, distal P=0.040). The endothelial cells were found in the surface of neointima. Newly born vessels could be found in the neointima and the new vessels were more in lovastatin group than in control group (proximal P=0.041, distal P=0.031). CONCLUSION: At the end of 4 weeks, the intimal hyperplasia with neovascularization was obviously near the anastomosis. Lovastatin showed the ability to inhibit the intimal hyperplasia and promote the neovascularization.

LAPTM4B allele *2 is a marker of poor prognosis for gallbladder carcinoma.

BACKGROUND: Lysosomal protein transmembrane 4 beta (LAPTM4B) is a novel cancer-related gene which has two alleles designated LAPTM4B*1 and LAPTM4B*2. In this study we investigated the correlation of LAPTM4B genotype with prognosis and clinicopathologic features in patients who had undergone curative resection for gallbladder carcinoma (GBC). METHODOLOGY/PRINCIPAL FINDINGS: PCR assay was performed to determine the LAPTM4B genotype in 85 patients. The correlation of LAPTM4B genotype with clinicopathologic parameters was assessed with the Chi-squared test. Differences in patient survival were determined by the Kaplan-Meier method. Multivariate analysis of prognostic factors was carried out with Cox regression analysis. Patients with LAPTM4B *2 had both significantly shorter overall survival (OS) and shorter disease-free survival (DFS) (both P<0.001). Multivariate analysis showed that LAPTM4B genotype is a prognostic factor for OS and DFS (both P<0.001). CONCLUSIONS/SIGNIFICANCE: LAPTM4B allele *2 is a risk factor associated with poor prognosis in patients with resected GBC, and LAPTM4B status may be therefore be useful preoperatively as an adjunct in evaluation of the operability of GBC.

Reduced expression of argininosuccinate lyase is closely associated with postresectional survival in hepatocellular carcinoma: an immunohistochemistry study of 61 cases.

Argininosuccinate lyase (ASL) is an important enzyme in the hepatic urea cycle, and catalyzes the reversible reaction of argininosuccinate to arginine and fumarate. Its expression is significantly reduced in some hepatocellular carcinomas (HCC). In this study, we aimed to investigate the correlation of reduced ASL expression and clinicopathologic features and prognosis in HCC patients. Immunohistochemistry was used to determine the expression of ASL in HCC tissues from 61 patients who had undergone hepatic tumor resection. The correlation of ASL expression in HCC with background liver status, viral status, tumor size, portal vein invasion, histopathologic differentiation, early tumor recurrence, sex, and age were assessed with the χ(2) test. Patient survival and survival differences were determined by the Kaplan-Meier method and log-rank test. Cox regression (proportional hazard model) was used for multivariate analysis of prognostic factors. Strong positive staining was found in 39/61 HCCs and normal liver tissues, and reduced ASL staining was found in 22/61 HCCs (36.1%). Patients with low ASL expression had a significantly poorer overall survival and disease-free survival (both P<0.001). Reduced ASL expression in carcinoma tissues was also significantly associated with the tumor-node-metastasis stage and early tumor recurrence, and histopathologic differentiation and portal vein invasion (P<0.05). Cox regression analysis showed that ASL is an independent prognostic marker for HCC. Therefore, reduced ASL expression may be a novel maker for poor prognosis in HCC patients.

LAPTM4B allele *2 is a marker of poor prognosis following hepatic tumor resection for hepatocellular carcinoma.

BACKGROUND: Lysosomal protein transmembrane 4 beta (LAPTM4B) is a gene related to hepatocellular carcinoma that has two alleles designated LAPTM4B*1 and LAPTM4B*2. This study aimed to investigate the correlation of LAPTM4B genotype with prognosis and clinicopathologic features in patients who have undergone resection for hepatocellular carcinoma (HCC). METHODOLOGY/PRINCIPAL FINDINGS: The LAPTM4B genotype was analyzed by PCR in 68 patients who had undergone curative hepatic resection for hepatocellular carcinoma. The correlation of LAPTM4B genotype with clinicopathologic parameters was assessed with the Chi-squared test. Differences in patient survival were determined by the Kaplan-Meier method. Multivariate analysis of prognostic factors was carried out with Cox regression analysis. Patients with LAPTM4B *2 had both significantly shorter overall survival (OS) and shorter disease-free survival (DFS) (both P<0.001). Multivariate analysis showed that LAPTM4B genotype is an independent prognostic factor for OS and DFS (both P<0.001). CONCLUSIONS/SIGNIFICANCE: Allele *2 of LAPTM4B is a risk factor associated with poor prognosis in patients with resected HCC. LAPTM4B status may be useful preoperatively as an adjunct in evaluation of the operability of HCC.

Correlation of LAPTM4B polymorphisms with gallbladder carcinoma susceptibility in Chinese patients.

Gallbladder carcinoma (GBC) is a malignancy with an extremely poor prognosis. In order to improve the survival rate, identification of new susceptibility risk factors is of importance. Here, we report findings on the novel cancer-related gene lysosomal protein transmembrane 4 beta (LAPTM4B) that has two alleles designated LAPTM4B*1 and LAPTM4B*2. Allele *1 differs from allele *2 in that it contains one copy of a 19-bp sequence, whereas this sequence is duplicated in exon 1 of allele *2. This study aimed to investigate the relationship of LAPTM4B allelic variation and GBC susceptibility. LAPTM4B genotype was analyzed in 155 healthy individuals and 91 GBC patients by PCR, and the genotypic distribution of LAPTM4B was analyzed with the chi-squared test. The frequency of allele *2 was 37.9 and 24.8% in the GBC and the control groups, respectively, representing a significant difference between these two groups (P<0.001). LAPTM4B allele *2 may be a risk factor associated with genetic susceptibility to GBC.

Correlation of LAPTM4B polymorphisms with hepatocellular carcinoma in Chinese patients.

Hepatocellular carcinoma (HCC) is the leading cause of cancer mortality in many countries. Evaluation of new susceptibility risk factors is therefore warranted in order to explore means to improve the survival rate. Here, we report on a novel HCC-related gene known as lysosomal protein transmembrane 4 beta (LAPTM4B) that has two alleles designated LAPTM4B*1 and LAPTM4B*2. Allele *1 differs from allele *2 in that it contains one copy of a 19-bp sequence, whereas this sequence is duplicated in allele *2 in exon 1 of LAPTM4B. In this study, we aimed to investigate the relationship between LAPTM4B allelic variation and HCC susceptibility. The LAPTM4B genotype was analyzed in the blood samples from 102 HCC patients and 135 healthy individuals by PCR. The genotypic distribution of LAPTM4B was analyzed using the chi-squared test. The frequencies of allele *2 were 38.24 and 24.07% in the HCC group and control group, respectively, representing a significant difference between these two groups (P<0.001). Thus, allele *2 of LAPTM4B appears to be associated with genetic susceptibility of HCC and may therefore be considered as a risk factor.