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Ping Tang

Publications and source records attributed to Ping Tang.

18 recordsLinked to original sources
PubMed2026

Integrated electronic nose, GC-MS, and metagenomic analyses reveal volatile flavor and microbial community differences in heap-fermented grains of Jiangxiangxing Baijiu across different fermentation degrees.

The fermentation degree of heap-fermented grains in Jiangxiangxing Baijiu production is a critical factor influencing base Baijiu quality. However, conventional assessment methods largely rely on empirical experience and therefore suffer from limited objectivity and accuracy. In this study, integrated volatile profiling and metagenomic approaches were employed to investigate volatile characteristics and microbial functional potential differentiation in fermented grains with different fermentation degrees (under-fermented, normally fermented, and over-fermented). Significant differences in physicochemical properties were observed among fermentation degrees, particularly in acidity and reducing sugar content. Electronic nose analysis revealed distinct sensor response patterns among different fermentation degrees, indicating differences in overall volatile odor fingerprint patterns. A total of 81 volatile compounds were identified by HS-SPME-GC-MS, with aldehydes, ketones, and pyrazines showing pronounced variations among fermentation degrees, and acetaldehyde exhibiting strong discriminatory potential. LEfSe analysis identified 18 microbial taxa as potential biomarkers associated with different fermentation degrees, including Pichia kudriavzevii, Lentibacillus daiqui, and Acetobacter pasteurianus. Correlation analysis revealed significant positive associations between acetaldehyde levels and Acetobacter abundance. Furthermore, KEGG, CAZy, and eggNOG analyses revealed differentiated functional potentials among fermentation degrees, providing insights into the potential metabolic basis associated with flavor differentiation. Overall, these findings highlight that fermentation degree differentiation is closely associated with coordinated changes in physicochemical conditions, microbial communities, and functional potentials, providing ecological insights into flavor differentiation and theoretical support for objective fermentation degree evaluation and quality control of Jiangxiangxing Baijiu production.

Fermentation↗
PubMed2007

Ductal carcinoma in situ: a review of recent advances.

PURPOSE OF REVIEW: This review summarizes recent findings on ductal carcinoma in situ of the breast and their impact on prognosis and management of the disease. RECENT FINDINGS: Great advances have been made in our understanding of ductal carcinoma in situ. Nuclear grading is probably the most important pathological factor that affects clinical outcome and correlates with distinct genetic pathways. Identifying key molecules in each pathway may provide better markers for prognostic, predictive and therapeutic purposes. Not all cases of ductal carcinoma in situ will progress to invasive ductal carcinoma, and identifying this subgroup of patients should lead to a reduction of overtreatment. Progenitor cell theory at the cellular level and sick lobe theory at the architectural level may help provide a better understanding of ductal carcinoma in situ from a different perspective and facilitate the development of individualized therapy. Prevention of local recurrence is the primary goal for treatment. Debate continues, however, on the use of radiotherapy, hormonal therapy, and sentinel lymph node biopsy. A panel of molecular markers may be needed for accurately predicting clinical outcome for the disease. SUMMARY: Understanding the carcinogenesis of ductal carcinoma in situ at the molecular level may lead to an optimal individualized therapy with minimal over or undertreatment.

Biomarkers↗
PubMed2006

Determination of monoamines in urine by capillary electrophoresis with field-amplified sample stacking and amperometric detection.

A simple, rapid and low-cost method using capillary electrophoresis coupled with field-amplified sample stacking and electrochemical detection was developed for the separation and determination of monoamines. In this present work, a systematic study of the parameters (pH value and concentration of electrophoretic buffer, composition of sample solvent, injection voltage and time) affecting separation and on-line concentration of monoamines has been performed enabling the detection sensitivity of these monoamines to be improved by 5,000 times compared with the conventional electrokinetic injection. This developed method was applied to the direct analysis of these monoamines in human urine without off-line sample preconcentration. Due to the requirement for urine dilution to minimize the detrimental effects of high salt on analyte stacking, the real sensitivity improvement is about 50-fold when applying the optimized method to urine samples. In order to quantitate these monoamines accurately, internal standard calibration curves were constructed with standard monoamines in presence of salt with similar concentration as in human urine. In the method validation, the calibration curves were linear over a range of 1.0 x 10(-9) to 2.5 x 10(-8) mol/L for each monoamine and the limits of detection (signal to noise ratio of 3) for these monoamines were in the sub-nmol/L concentration range (6.0 x 10(-10) mol/L).

Catecholamines↗
PubMed2006

Aggregates in solution of binary mixtures of amphiphilic diblock copolymers with different chain length.

The polydispersity effect of amphiphilic AB diblock copolymers on the self-assembled morphologies in solution has been investigated by the real-space implementation of self-consistent field theory (SCFT) in two dimensions (2D). The polydispersity is artificially obtained by mixing binary diblock copolymers where the hydrophilic or hydrophobic blocks are composed of two different lengths while the other block length is kept the same. The main advantage is that this simple polydispersity can easily distinguish the difference of aggregates in the density distribution of long and short block length intuitionally and quantitatively. The morphology transition from vesicles to micelles is observed with increasing polydispersity of copolymers due to the length segregation of copolymers. For polydisperse hydrophilic or hydrophobic blocks, the short blocks tend to distribute at the interfaces between hydrophilic and hydrophobic blocks while the long blocks stretch to the outer space. More specifically, by quantitatively taking the sum of all the concentration distribution of long and short chains over the inside and outside surface areas of the vesicle, it is found that long blocks prefer to locate on the outside surface of the vesicle while short ones prefer the inside. Such length segregation leads to large curvature of the aggregate, thus resulting in the decrease of the aggregate size.

Journal Article↗
PubMed2006

Relationship between nuclear grade of ductal carcinoma in situ and cell origin markers.

Ductal carcinoma in situ (DCIS) is a group of heterogeneous lesions genetically, morphologically, and biologically. Recently, breast epithelium in the terminal ductal lobular unit has been sub-classified based on the expression of several cytokeratin markers as stem cells (CK5/6 +), luminal cells (CK8, CK18 +), and basal cells (CK14, CK17 +). In this study we describe the relationship between DCIS of different nuclear grades (non-high grade and high grade) and these cell origin markers. Fifty-three cases of non-high grade and 46 cases of high grade DCIS were selected, and representative sections from each case were stained with antibodies to these cytokeratin markers. High grade DCIS showed significantly higher rates of expression with stem and basal cell markers compared with non-high grade DCIS (p <0.05). The majority of DCIS, both high grade and non-high grade, expressed luminal cell markers (67% to 91%) and single type of cell origin marker (72% to 87%). High-grade DCIS more frequently co-expressed all three types of cell origin markers compared with non-high grade DCIS (p <0.05). In summary, a subset of high grade DCIS frequently rises from stem or/and basal cell populations; the subset is associated with poor prognosis in invasive breast carcinoma. Thus, these markers may be used to identify a potentially more aggressive subgroup of breast carcinoma at its pre-invasive stage (DCIS), and to manage it accordingly. Second, most DCIS express luminal cell markers, suggesting that malignant transformation occurs relatively late along the cell differentiation pathway, contrary to the traditional belief that most neoplasms arise from a more primitive stem cell population. Third, the majority of DCIS exclusively express one type of progenitor marker, indicating that in most incidences they may arise from a single progenitor population. Last, triple expression of all types of cell origin marker is frequently associated with high grade DCIS, suggesting that more complicated pathways are involved in these more aggressive lesions. Further studies are needed to delineate the relationships of cell origin markers in DCIS and invasive carcinoma to the clinical outcome.

Biomarkers, Tumor↗
PubMed2006

[Analysis of changes of anterior chamber depth after IOL implantation].

OBJECTIVE: To evaluate the changes of the anterior chamber depth (ACD) and the related factors after cataract surgery with IOL implantation in order to achieve the intended postoperative refraction. METHODS: Preoperative and postoperative ACD were examined in 117 patients (177 eyes) who underwent cataract surgery (phacoemulsification and posterior chamber IOL implantation). Correlations between changes of ACD and the axial lengths of the eyes, K-readings and IOL A-constants were assessed. Patients were followed-up for 3 to 24 months. RESULTS: (1) There was significant difference between preoperative ACD (3.19 +/- 0.39) mm and postoperative ACD (4.22 +/- 0.65) mm (P = 0.000). (2) The mean postoperative ACD change was (1.03 +/- 0.61) mm. The correlations between the ACD changes and the axial lengths of the eye and K-readings were statistically significant. (r = 0.866, r = 0.946, P = 0.001). (3) There was significant difference between preoperative ACD and postoperative ACD in the three different A-constants groups (118.9, 118.0 and 118.4) (P = 0.004, 0.001 and 0.001). There was significant difference between ACD changes in patients with A-constant 118.9 and that of 118.0 or 118.4 (P = 0.007, P = 0.01). There was no significant difference between ACD changes in patients with A-constant 118.0 and that of 118.4 (P = 0.957). CONCLUSION: Cataract surgery deepened anterior chambers at varying degrees, depending on the axial lengths of the eye, K-readings and the IOL A-constants. ACD changes and relevant factors should be considered in studying the accuracy of IOL refraction formula and in adjusting the calculated data.

Aged↗
PubMed2006

Expression patterns of ER-alpha, PR, HER-2/neu, and EGFR in different cell origin subtypes of high grade and non-high grade ductal carcinoma in situ.

We have previously reported that high grade and non-high grade ductal carcinoma in situ (DCIS) of the breast can be subdivided into 3 cell origin subtypes (luminal, basal/stem, and null), and that high grade DCIS is more frequently associated with basal/stem cell subtypes compared to non-high grade DCIS. Here we refine the relationships between these 3 subtypes and the expression patterns of estrogen receptor-alpha (ER-alpha), progesterone receptor (PR), HER-2/neu, and epidermal growth factor receptor (ERFR) in 53 cases of non-high grade and 46 cases of high nuclear grade DCIS. Using a panel of antibodies to ER-alpha, PR, HER-2/neu, and EGFR, along with cytokeratin (CK) markers (CK5/6, CK8, CK14, CK17, and CK18), we found that all 3 cell origin subtypes can express ER-alpha and PR, and their expression is higher in non-high grade DCIS than in high grade DCIS; the expression of HER-2/neu is associated with luminal subtype only in non-high grade DCIS, but can be seen in all 3 subtypes in high grade DCIS; the expression of EGFR is low and is present only in luminal cell subtypes in both high and non-high grade DCIS. Basal/ stem cell and null cell subtypes occur in younger patients in non-high grade DCIS compared to high grade DCIS. In conclusion, the expression patterns of ER-alpha, PR, HER-2/neu, and EGFR are markedly different in different cell origin subtypes of both high grade and non-high grade DCIS, suggesting that cell origin subtypes as well as nuclear grade contribute to the biological and molecular heterogeneity of DCIS.

Adult↗
PubMed2005

Aggregate morphologies of amphiphilic ABC triblock copolymer in dilute solution using self-consistent field theory.

The complex microstructures of amphiphilic ABC linear triblock copolymers in which one of the end blocks is relatively short and hydrophilic, and the other two blocks B and C are hydrophobic in a dilute solution, have been investigated by the real-space implementation of self-consistent field theory (SCFT) in two dimensions (2D). In contrast to diblock copolymers in solution, the aggregation of triblock copolymers are more complicated due to the presence of the second hydrophobic blocks and, hence, big ranges of parameter space controlling the morphology. By tailoring the hydrophobic degree and its difference between the blocks B and C, the various shapes of vesicles, circlelike and linelike micelles possibly corresponding to spherelike, and rodlike micelles in 3D, and especially, peanutlike micelles not found in diblock copolymers are observed. The transition from vesicles to circlelike micelles occurs with increasing the hydrophobicity of the blocks B and C, while the transition from circlelike micelles to linelike micelles or from the mixture of micelles and vesicles to the long linelike micelles takes place when the repulsive interaction of the end hydrophobic block C is stronger than that of the middle hydrophobic block B. Furthermore, it is favorable for dispersion of the block copolymer in the solvent into aggregates when the repulsion of the solvent to the end hydrophobic block is larger than that of the solvent to the middle hydrophobic block. Especially when the bulk block copolymers are in a weak segregation regime, the competition between the microphase separation and macrophase separation exists and the large compound micelle-like aggregates are found due to the macrophase separation with increasing the hydrophobic degree of blocks B and C, which is absent in diblock copolymer solution. The simulation results successfully reproduce the existing experimental ones.

Journal Article↗
PubMed2005

Phase separation patterns for diblock copolymers on spherical surfaces: a finite volume method.

We explore phase separation on spherical surfaces by solving the Cahn-Hilliard equation modified for diblock copolymers using a finite volume method. The spherical surface is discretized into almost uniform triangles by employing successive dyadic refinements of the spherical icosahedron, a methodology that avoids potential mathematical and numerical problems related to the poles in spherical coordinates. The finite volume method is based on averaging Voronoi cells built from triangular meshes to calculate the Laplace-Beltrami operator on the curved surface, which greatly improves both the accuracy and speed of calculation as compared to the conventional finite difference method. By using this method we simulate the phase separation of diblock copolymers on a spherical surface. It is found that stable and intrinsic defects, which would not occur in a flat space after sufficient annealing, appear in the periodic arrangement of the domains on the curved surface due to the distinct Euler characteristic of the surface.

Journal Article↗
PubMed2005

[Multidimensional separations used in pharmaceutical and biological fields].

A review of multidimensional separations such as comprehensive two-dimensional gas chromatography (GC x GC), comprehensive two-dimensional high performance liquid chromatography (HPLC x HPLC) and their applications in pharmaceutical and biological fields is presented with 71 references. A single CO2 cryo-jet loop modulator was developed for GC x GC and it can be used to modulate compounds higher than C6 effectively. Comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC x GC/TOF-MS) analyses of traditional Chinese medicine volatile oils such as Pogostemon cablin Benth (Cablin Patchouli), Forsythia suspensa (Thunb.) Vahl and Zedoary were reported also. As an emerging technology, multidimensional separations hold the promise and play an important role in the future pharmaceutical and biological fields.

Animals↗
PubMed2004

Morphology and phase diagram of complex block copolymers: ABC linear triblock copolymers.

Using a real space implementation of the self-consistent field theory for the polymeric system, we explore microphases of ABC linear triblock copolymers. For the sake of numerical tractability, the calculation is carried out in a two-dimensional (2D) space. Seven microphases are found to be stable for the ABC triblock copolymer in 2D, which include lamellae, hexagonal lattice, core-shell hexagonal lattice, tetragonal lattice, lamellae with beads inside, lamellae with beads at the interface, and hexagonal phase with beads at the interface. By systematically varying the composition, triangle phase diagrams are constructed for four classes of typical triblock polymers in terms of the relative strengths of the interaction energies between different species. In general, when both volume fractions and interaction energies of the three species are comparable, lamellar phases are found to be the most stable. While one of the volume fractions is large, core-shell hexagonal or tetragonal phases can be formed, depending on which of the blocks dominates. Furthermore, more complex morphologies, such as lamellae with beads inside, lamellae with beads at the interface, and hexagonal phases with beads at the interface compete for stability with lamellae structures, as the interaction energies between distinct blocks become asymmetric. Our study provides guidance for the design of microstructures in complex block copolymers.

Journal Article↗
PubMed2004

Right ventricle-sparing heart transplantation effective against iatrogenic pulmonary hypertension.

BACKGROUND: Right heart failure is the predominant cause of death following heart transplantation, occurring with disturbingly high frequency in patients with severe antecedent pulmonary hypertension. We have recently reported a novel technique of heart transplantation that spares the recipient right ventricle, excising only the recipient left ventricle. The resulting model has 2 right hearts and 1 left heart. The aim is to preserve the recipient's right ventricle, which is already conditioned to pulmonary hypertension. The hope is that, in this way, death due to right heart failure can be prevented in humans. Our prior report was a feasibility study in normal dogs. This study challenges this new technique by creating iatrogenic pulmonary hypertension in the recipient animals. METHODS: Iatrogenic pulmonary hypertension was created in 4 recipient canines by intravenous injection of the pulmonary toxin monocrotaline pyrrole (single bolus of 3.5 to 4.5 mg/kg intravenously [i.v.]). RESULTS: Within 6 weeks of monocrotaline administration, relative pulmonary hypertension occurred (mean pulmonary artery [PA] pressure 20 mm Hg vs 10 mm Hg for controls [p < 0.01]) (pulmonary vascular resistance [PVR] 4.2 vs 1.5 Wood units [P < 0.01]), and right ventricular (RV) hypertrophy developed (RV thickness 11 mm vs 2 mm [P < 0.04]). Histologic examination confirmed severe muscle infiltration and thickening of the media of the pulmonary arterioles. RV-sparing heart transplantation was performed successfully in all 4 animals with pulmonary hypertension. In all cases, the animals were weaned without difficulty from cardiopulmonary bypass, despite the ambient pulmonary hypertension, on low-dose epinephrine, maintaining systolic blood pressure of 104 mm Hg at right atrial pressure of 7 mm Hg. Both right hearts contracted well without dilation or strain. A single "control" traditional orthotopic transplant experiment in an animal with monocrotaline-induced pulmonary hypertension resulted in immediate death from right heart failure. CONCLUSIONS: Right ventricle-sparing heart transplantation ("one-and-one-half heart model") can handle pulmonary hypertension without difficulty. This evidence adds impetus for further pursuing of right ventricle-sparing heart transplantation to decrease the incidence of death from right heart failure in recipients with severe antecedent pulmonary hypertension.

Alkylating Agents↗
PubMed2004

Inlet patch: prevalence, histologic type, and association with esophagitis, Barrett esophagus, and antritis.

CONTEXT: Inlet patch is a congenital anomaly of the cervical esophagus consisting of gastric mucosa. Case reports have documented the histologic type and its associated complications. OBJECTIVE: To report the prevalence and histologic types of inlet patch as well as its association with Barrett esophagus and Helicobacter pylori-associated gastritis. DESIGN: We reviewed 1821 consecutive pathology reports from endoscopies of the upper gastrointestinal tract between 1995 and 2002 and identified 20 patients with inlet patch. The patients' ages ranged from 16 to 75 years (mean, 55 years). We examined biopsies from these patients of the cervical esophagus, distal esophagus, and antrum that had been stained with hematoxylin-eosin and the Steiner stain. Biopsies from the cervical esophagus composed of nonoxyntic gastric mucosa were also stained for gastrin-producing cells. RESULTS: In our patient population, inlet patch occurred in 1.1% of all patients in whom an inlet patch had been searched for endoscopically and a biopsy performed. In the inlet patch, oxyntic mucosa was the most common histologic type (11/20), followed by cardiac mucosa (5/20). Four specimens of the inlet patch contained only foveolar epithelium and were therefore considered too superficial to be classified. Twelve of 20 biopsies of the inlet patch were inflamed, and 1 of them was associated with H pylori. Pancreatic acinar tissue was noted in 2 patients; no intestinal metaplasia was found. In the distal esophagus, 4 patients with inlet patch had distal esophagitis, 4 had Barrett esophagus, 5 had oxyntic mucosa, 3 had pancreatic acinar tissue (1 coexisting with oxyntic mucosa), and 5 presented with only unremarkable esophageal squamous mucosa. Antral gastritis was seen in 2 patients, 1 of them with H pylori. The same patient also had H pylori in the inlet patch. CONCLUSION: Inlet patch occurred in about 1% of our study population. Oxyntic mucosa constituted the most common histologic type; inflammation was common. The H pylori infection of the inlet patch correlated with that of the antrum. None of the inlet patch biopsies showed intestinal metaplasia. Pancreatic acinar tissue occurred with similar frequency in the inlet patch and distal esophagus. Esophagitis was noted in 25% of the patients with inlet patch, and Barrett esophagus was noted in 20%.

Adolescent↗
PubMed2003

Incidental finding of mammary carcinoma in lumpectomy specimens.

More and more breast lumpectomies are being performed due to mammographic screening, and both in situ and invasive breast carcinomas are being detected earlier and smaller in size. The objective of this study was to determine the presence of incidental microscopic breast carcinoma in mammography-guided lumpectomy specimens. A prospective study was carried out by processing in surgical pathology approximately 9,000 breast lumpectomy specimens during a 2.5-yr period so that the entire specimens were embedded for microscopic examination. Excluded from the study were cases with grossly or microscopically identified carcinomas greater than 10 mm2, and non-invasive carcinomas diagnosed in association with invasive carcinoma. Cases with multifocal carcinomas, prior diagnosis of breast cancer, or prior history of breast biopsy were also excluded. Carcinomas present in the same tissue blocks as the clinically suspected lesions such as palpable nodules, microcalcification, or other mammographic abnormalities were excluded as well. Fifty cases of incidental microscopic mammary carcinoma were found including 8 infiltrating ductal carcinomas (IDC), 2 infiltrating lobular carcinomas (ILC), 21 intraductal carcinomas (DCIS), and 19 lobular carcinomas in situ (LCIS). All of the lesions were solitary, located in indistinct loosely arranged fibrous and adipose stromal tissues, and the majority of them were near or at the inked excisional margins. Physicians who care for patients with breast cancer should be aware of the existence of these minute breast carcinomas that are often near or at the surgical margins. The significance of these microscopic findings for therapeutic strategy and prognosis should be determined by long-term follow-up.

Adipose Tissue↗
PubMed2003

[Selection of IOL power formula for patients with cataract and high myopia].

OBJECTIVE: To compare the accuracy of two IOL power formulas (SRK-T and SRK-II) in order to improve the accuracy of predicative IOL powers for patients with cataract and high myopia. METHODS: (1) Patient's axial lengths of the eye, K-readings and A-constants were input to the SRK-T and SRK-II formulas. The differences in predicative refraction between the two formulas were compared. (2) Eight six patients (130 eyes) with cataract and high myopia underwent phacoemulsification and posterior chamber IOL implantation were studied. These patients were randomly divided into two groups and received IOL whose power was determined by either SRK-T or SRK-II. Three months after IOL implantation, the postoperative refractions were recorded and compared with predictive refractions. Patients were followed-up for 3 to 24 months. RESULTS: (1) When K-reading was 43.00 D, there was no statistically significant difference between the results from these two formulas (P > 0.05) and there was no correlation between the difference and the axial lengths (P > 0.05). In eyes with K-reading at 39.00 D, 41.00 D, 45.00 D, or 47.00 D, there was statistically significant difference between the results from these two formulas (P < 0.05). The difference between the two formulas was in proportional to the axial length (P < 0.05). (2) The mean error between the postoperative refraction and predictive refraction determined by SRK-T and SRK-II formula was 0.08 D and -0.79 D, respectively. The difference between these two formulas was statistically significant (P < 0.05). CONCLUSION: Selection of IOL power formula should consider the axial length, K-reading and other related factors. SRK-T formula is appropriate for high myopia eyes with axial length longer than 26.0 mm. In this group, SRK-T formula is much more accurate than the SRK-II formula.

Aged↗
PubMed2003

Mature cystic teratoma of the ovary associated with complete colonic wall and mucinous cystadenoma.

Mature cystic teratomas of the ovary frequently contain intestinal type epithelium, but they are rarely associated with complete intestinal wall. The association of mature cystic teratoma with mucinous cystadenoma is not unusual. However, the pathogenetic relationship between these two lesions remains unanswered. We report a mature cystic teratoma of the ovary in a 16-yr old female that contained a complete colonic wall in continuity with an endocervical-type mucinous cystadenoma. Both the mucinous cystadenoma and the colonic wall showed the typical histopathological and immunohistochemical patterns of classical mucinous cystadenoma (positive for CK7, negative for CK20) and normal colonic wall (positive for CK20, negative for CK7), respectively. The microscopic and immunohistochemical patterns of the epithelium from the transitional zone between colonic wall-like structure and mucinous cystadenoma demonstrated features of both types of epithelium, positive for both CK7 and CK20, and focally positive for a neuroendocrine marker, chromogranin, which is normally present in colonic mucosa. These results suggest that the mucinous cystadenoma originated from the colonic epithelium of the mature cystic teratoma.

Adolescent↗
PubMed2002

Screw placement of pedicle of vertebral arch--pay great attention to segmental differences of the pedicle.

OBJECTIVE: To investigate appropriate ways for screw placement of pedicle of vertebral arch in the horizontal plane. METHODS: Fifteen preserved thoracolumbar spine specimens (T(11)-L(5)) were used and divided into three groups at random. Firstly four anatomic parameters indicating screw positions in the horizontal plane were measured. Secondly the methods of Roy-camille, Magerl, and authors' segmental differences were used to place successively the screws of the pedicles with 5 mm, 6 mm, and 7 mm in diameter. Coincidences between the drilling point, drilling direction and pedicle axis, and ruptures of the pedicle as well as the length of the screw in the vertebral body were observed. RESULTS: Four anatomic parameters at various segments showed significant differences (P<0.05). The drilling point by the Roy-camille's method deviated medial to pedicle axis in most segments, and its drilling direction did not coincide well with most E-angles of the pedicles. The drilling point by Magerl's method coincided relatively well with pedicle axis in lumbar vertebrae, but there were still some differences between its drilling direction and E-angles of the pedicles. The method of segmental differences coincided the best with the pedicle axis. The lengths of screw in the vertebra were relatively long by both Magerl and segmental difference methods. When 5 mm diametral screw was used by the three methods, the rupture rate was very low. When 6 mm and 7 mm diametral screws were placed, the rupture rate was accordingly increased. Of the three methods, Roy-camille's method showed a relatively high rupture rate, while the method of segmental differences a comparatively low rupture rate. Various degrees of rupture of the pedicle of vertebral arch were found at the juncture of the thoracic and lumbar vertebrae when 6 mm or 7 mm diametral screws was used by any screw placement method. In contrast, the rupture was seldom seen at the lower lumbar vertebrae when 7 mm diametral screws were used. CONCLUSIONS: The segmental difference method is proved to have the anatomic safety and screw biomechanical stability. It is appropriate to choose different diametral screws, different drilling points and directions according to different segments of the vertebra.

Adult↗