Biomedical subjects

Yu Zhang

Publications and source records attributed to Yu Zhang.

329 records · Page 19Linked to original sources

PubMed2002

[Registration and 3D rendering of serial tissue section images].

It is an important morphological research method to reconstruct the 3D imaging from serial section tissue images. Registration of serial images is a key step to 3D reconstruction. Firstly, an introduction to the segmentation-counting registration algorithm is presented, which is based on the joint histogram. After thresholding of the two images to be registered, the criterion function is defined as counting in a specific region of the joint histogram, which greatly speeds up the alignment process. Then, the method is used to conduct the serial tissue image matching task, and lies a solid foundation for 3D rendering. Finally, preliminary surface rendering results are presented.

Algorithms↗

PubMed2002

[FTIR investigation on crystal chemistry of CO(2-)3-substituted apatite solid solutions prepared through different methods].

The CO(2-)3-substituted apatite solid solutions were prepared through different methods. The FTIR and XRD measurements were applied to investigate its crystal chemistry properties. The results indicated that the CO(2-)3-substituted sites in the carbonate hydroxyapatite(CHAP) prepared through homogeneous precipitation method are type-B in which [CO3.OH] tetrahedral-coordinations are substituted for [PO4] tetrahedral-coordinations; the ones in the CHAP prepared through solid phase ions exchange method are type-A in which [CO3] triangle-coordinations are substituted for [OH] in column sites; the ones in the carbonate fluorapatite(CFAP) prepared through solid phase reaction method are type-B in which [CO3.F] tetrahedral-coordinations are substituted for [PO4] tetrahedral-coordinations; the ones in the CHAP prepared through sol-gel method are AB mixed-type. The vibrational band psi 3 is splitted into psi 3-1, psi 3-4 and psi 3F. The psi 3F is combined by psi 3-2 (type-A) and psi 3-3 (type-B) in Gaussian function fitting. When Wco(2-)3 < 3.34%, substitution value of type-A increases with the increasing of CO(2-)3 contents. When Wco(2-)3 = 3.34%, substitution value of type-A has maximum. When 3.34% < Wco(2-)3 < 7.52%, substitution value of type-B increases with the increasing of CO(2-)3 contents. When Wco(2-)3 = 7.52%, substitution value of type-B has maximum.

Apatites↗

PubMed2002

Endoscopic retrograde cholangiopancreatography in evaluation of choledochal dilatation in patients with obstructive jaundice.

OBJECTIVE: To determine the causes of choledochal dilatation in patients with obstructive jaundice. METHODS: One hundred and sixty-four patients with obstructive jaundice were investigated by endoscopic retrograde cholangiopancreatography(ERCP), and patients with choledochal dilatation (group I, n=110) were compared with those without choledochal dilatation (group II, n=54). RESULTS: The causes of common bile duct dilatation were choledocholith, juxtapapillary duodenal diverticula and congenital dilatation of the common bile duct. The distal common bile duct and its surroundings were abnormal in 104 (94.55%) of the 110 patients and in 13 (24.08%) of the 54 patients (P<0.01). Juxtapapillary duodenal diverticulum accounted for 24.55% in group I, and only in 9.26% in group II (P<0.05). Post-cholecystectomy patients were 13.64% in group I, and only 5.56% in group II. CONCLUSIONS: The abnormalities of the distal common bile duct and its surroundings can usually be detected as underlying causes of common bile duct dilatation. ERCP is necessary before cholecystectomy, since it is considered the "gold standard" for the diagnosis of distal common bile duct abnormalities.

Adult↗

PubMed2001

Registration of serial tissue section images.

OBJECTIVE: This study aims to tackle the problem of image registration during computer-assisted three-dimensional (3D) reconstruction of serial tissue sections. METHODS: We proposed segmentation-counting algorithm for computerized image registration on the basis of joint histogram. This approach utilizes thresholding of the 2 images to be registered, and the criterion function is defined as the counting in a specific region of the joint histogram. The registration parameters can be obtained by optimizing the criterion function. RESULTS: In the trial application of this approach in image registration for the serial tissue sections of mouse wse embryos, a more efficient result was achieved. CONCLUSION: The method can rapidly accomplish the image registration task for serial tissue sections with simpler calculation processes.

Journal Article↗

PubMedDate not supplied

Comparison of Epstein-Barr virus DNA level in plasma, peripheral blood cell and tumor tissue in nasopharyngeal carcinoma.

BACKGROUND: The plasma Epstein-Barr virus DNA (EBV-DNA) level has been found to be an indicator for staging and prognosis of nasopharyngeal carcinoma (NPC). MATERIALS AND METHODS: The EBV-DNA level in plasma, peripheral blood cells (PBC) and neoplastic tissues was quantitatively analyzed and potential associations with clinical parameters of NPC were investigated. RESULTS: The plasma EBV-DNA detecting rate and level in NPC (92%, 82,500 copies/ml) was significantly higher than that in NPC after treatment (19%, 0 copy/ml) and in controls (12%, 0 copy/ml) (p < 0.001); while there was no significance of the PBC EBV-DNA detecting rate and EBV-DNA load in NPC before (24%, 0 copy/actin) and after treatment (14%, 0 copy/actin), and in controls (16%, 0 copy/actin). The plasma EBV-DNA level was not correlated to the PBC EBV-DNA load in NPC before (p = 0.92) and after treatment (p = 0.267), and in controls (p = 0.735). The EBV-DNA level in NPC tumor (27.8 copies/actin) was significantly higher than that in nasopharyngitis and was positively correlated to the ratio of EBER1-positive cells on the NPC section (p = 0.001). The plasma EBV-DNA level was significantly increased in TNM stages I, II, III and IV NPC, whereas there was no significant difference of PBC EBV-DNA load in different stage NPC. CONCLUSION: Our results indicate that plasma EBV-DNA is a more sensitive and reliable biomarker than PBC EBV-DNA for diagnosis, staging and therapeutic effect evaluation at a molecular level in NPC clinical practice. Plasma EBV-DNA may derive from the cancer cells and PBC EBV-DNA from circulating mononuclear cells in NPC patients.

DNA, Viral↗