[Combined resection of thoracic and abdominal organ clusters: a series of 50 cases].

Objective: To examine the technique and effect of combined thoracic and abdominal organ clusters resection. Methods: From February 2019 to August 2021, totally 50 cases of combined thoracoabdominal organ cluster resection were completed at Transplant Medical Center, the Second Affiliated Hospital of Guangxi Medical University from donation after brain death donors. There were 47 males and 3 females, aging (34.8±12.3) years (range: 5 to 55 years). The length of hospital stay(M(IQR)) was 4(4) days (range: 2 to 43 days), the length of tube time was 4(2) days (range: 1 to 43 days). Through the midsternal incision and the abdominal grand cross incision, the cold perfusion was performing simultaneously when the perfusion lines of each target organ was established respectively. The combined resection was performed with the diaphragm as the boundary and the organ cluster as the unit. The heart and lung were separated on site and sent to the transplant hospital, and the abdominal organ cluster was directly preserved and returned to our hospital for further separation and repair. Results: Totaly 21 hearts, 47 pairs of lungs, 49 livers, 47 pairs of kidneys and 11 pancreas were harvested by this surgical treatment. The resection time was (32.6±6.5) minutes (range: 19 to 50 minutes), with no hot ischemia time. There was no accidental injury that affected organ quality and function. Heart transplantation was performed in 17 cases, combined heart-kidney transplantation in 2 cases, double lung transplantation in 43 cases, single lung transplantation in 6 cases, liver transplantation in 41 cases, combined liver-pancreas-duodenal cluster transplantation in 1 case, combined liver-kidney transplantation in 3 cases, combined pancreas-kidney transplantation in 9 cases, and kidney transplantation in 74 cases. Conclusion: Simultaneous perfusion and combined resection of thoracic and abdominal organ clusters for donation after brain death donors are feasible and effective.

[Epidemic profile of mumps in China during 2004-2013].

OBJECTIVE: To analyze the epidemiological characteristics of mumps in China from 2004 to 2013. METHODS: Data of mump cases occurring between 2004 and 2013 were gathered from the national notifiable disease reporting system in China (excluding Hong Kong, Macao, and Taiwan); only cases classified as "final card" , laboratory confirmed, or clinical diagnosis were included. Descriptive epidemiology techniques were used to analyze features of sex, age, trends over time, and geography. RESULTS: Average incidence of mumps between 2004 to 2013 was 24.20/100 000. Peaks were in 2011 and 2012, with incidence 33.9/100 000 (454 385/1.340 million) and 35.6/100 000 (479 518/1.347 million). Two seasonal peaks occurred regularly in years, one from April to July in the first year, and the other from November to January in the next year. During the study period, provinces with the highest incidence were Ningxia, Tibet, Xinjiang, and Guangxi; incidences were 72.1/100 000 (4 425/6.13 million), 48.5/100 000 (1 396/3 million), 51.7/100 000 (10 887/21.04 million), and 40.8/100 000 (19 179/46.99 million), respectively. Guangdong (28 078), Sichuan (21 924), Guangxi (21 616), and Zhejiang (20 000) provinces reported the highest number of mumps cases. Beijing, Tianjin, and Shanghai showed a consistently low incidence. Mumps cases occurred primarily among children aged 5-9 years, with incidence ranging from 118.2/100 000 to 281.4/100 000. In 2004-2008, the peak age was 6-8 years (174.1/100 000) and in 2009-2013, peak age was 5-7 years (234.5/100 000). CONCLUSION: The highest incidences of mumps in China were reported in 2011 and 2012, with children of school age constituting the majority of cases.

Targeted modification of wheat grain protein to reduce the content of celiac causing epitopes.

The prolamin peptides in wheat gluten and in the homologous storage proteins of barley and rye cause painful chronic erasure of microvilli of the small intestine epithelium in celiac patients. If untreated, it can lead to chronic diarrhea, abdominal distension, osteoporosis, weight-loss due to malabsorption of nutrients, and anemia. In addition to congenital cases, life-long exposure to gluten proteins in bread and pasta can also induce development of celiac sprue in adults. To date, the only effective treatment is life-long strict abstinence from the staple food grains. Complete exclusion of dietary gluten is, however, difficult due to use of wheat in many foods, incomplete labeling and social constraints. Thus, finding alternative therapies for this most common foodborne disease remained an active area of research, which has led to many suggestions in last few years. The pros and cons associated with these therapies were reviewed in the present communication. As different celiac patients are immunogenic to different members of the undigestible proline/glutamine rich peptides of ~149 gliadins and low molecular weight glutenin subunits as well as the six high molecular weight glutenin subunits, an exhaustive digestion of the immunogenic peptides in the stomach, duodenum, jejunum, and ileum of celiacs is required. In view of the above, we evaluated the capacity of cereal grains to synthesize and store the enzymes prolyl endopeptidase from Flavobacterium meningosepticum and the barley cysteine endoprotease B2, which in combination are capable of detoxifying immunogenic gluten peptides in a novel treatment of celiac disease.

Sex-based differences in bacterial meningitis in adults: Epidemiology, clinical features, and therapeutic outcomes.

BACKGROUND: To investigate the sex-based differences in clinical features, causative pathogens, and outcomes of hospital-based culture-proven adult bacterial meningitis. OBJECTIVE: This retrospective study enrolled 621 patients at a tertiary medical center. To compare changes over time, the presentation of disease among the enrolled patients was divided into two equal time periods: the first study period (1986-2002) and the second study period (2003-2019). RESULTS: Of the 621 patients enrolled in this study, 396 were males and 225 were females. The overall case fatality rate was 30.4% with 30.1% and 31.1% in males and females, respectively. Regarding the causative pathogens, there was a rising incidence of coagulase-negative staphylococcal infections and a decreasing incidence of Klebsiella pneumoniae infection in both male and female in the second study period. The prevalence of patients with nosocomial infection in a postneurosurgical state were 41.9% (68/162) in the first study period and 58.1% (94/162) in the second study period in male group, and 34.8% (32/92) in the first study period and 65.2% (60/92) in the second study period in female group, respectively. Significant factors between the sexes difference included age (P = 0.004), traumatic brain injury (P = 0.01), alcoholism (P < 0.001), brain tumor (P < 0.001), systemic lupus erythematosus (SLE) (P = 0.004), presence of diabetic ketoacidosis/hyperglycemic hyperosmolar state (P = 0.033), brain abscess (P = 0.042), and total protein (P = 0.002) and white blood cell count (P = 0.036) of cerebrospinal fluid data. CONCLUSION: Our study revealed an increase in the number of patients with nosocomial infection with a postneurosurgical state in both male and female in the second study period. Males were younger and frequently presented with a history of head trauma and alcoholism with concomitant brain abscesses while females presented with SLE and brain tumor. The therapeutic outcome did not show differences between the sexes.

The support of matrix accumulation and the promotion of sheep articular cartilage defects repair in vivo by chitosan hydrogels.

OBJECTIVE: Chitosan has been widely used as an injectable scaffold in cartilage tissue engineering due to its characteristic biocompatibility and biodegradability. In this study, chitosan was used in its hydrogel form as a scaffold for chondrocytes that act to reconstruct tissue-engineered cartilage and repair articular cartilage defects in the sheep model. This study aims to find a novel way to apply chitosan in cartilage tissue engineering. METHODS: Temperature-responsive chitosan hydrogels were prepared by combining chitosan, beta-sodium glycerophosphate (GP) and hydroxyethyl cellulose (HEC). Tissue-engineered cartilage reconstructions were made in vitro by mixing sheep chondrocytes with a chitosan hydrogel. Cell survival and matrix accumulation were analyzed after 3 weeks in culture. To collect data for in vivo repair, reconstructions cultured for 1 day were transplanted to the freshly prepared defects of the articular cartilage of sheep. Then at both 12 and 24 weeks after transplantation, the grafts were extracted and analyzed histologically and immunohistochemically. RESULTS: The results showed that the chondrocytes in the reconstructed cartilage survived and retained their ability to secrete matrix when cultured in vitro. Transplanted in vivo, the reconstructions repaired cartilage defects completely within 24 weeks. The implantation of chitosan hydrogels without chondrocytes also helps to repair cartilage defects. CONCLUSIONS: The chitosan-based hydrogel could support matrix accumulation of chondrocytes and could repair sheep cartilage defects in 24 weeks. This study showcased the success of a new technique in its ability to repair articular cartilage defects.

Technical Note: Evaluation of the systematic accuracy of a frameless, multiple image modality guided, linear accelerator based stereotactic radiosurgery system.

PURPOSE: To evaluate the total systematic accuracy of a frameless, image guided stereotactic radiosurgery system. METHODS: The localization accuracy and intermodality difference was determined by delivering radiation to an end-to-end prototype phantom, in which the targets were localized using optical surface monitoring system (OSMS), electromagnetic beacon-based tracking (Calypso®), cone-beam CT, "snap-shot" planar x-ray imaging, and a robotic couch. Six IMRT plans with jaw tracking and a flattening filter free beam were used to study the dosimetric accuracy for intracranial and spinal stereotactic radiosurgery treatment. RESULTS: End-to-end localization accuracy of the system evaluated with the end-to-end phantom was 0.5 ± 0.2 mm with a maximum deviation of 0.9 mm over 90 measurements (including jaw, MLC, and cone measurements for both auto and manual fusion) for single isocenter, single target treatment, 0.6 ± 0.4 mm for multitarget treatment with shared isocenter. Residual setup errors were within 0.1 mm for OSMS, and 0.3 mm for Calypso. Dosimetric evaluation based on absolute film dosimetry showed greater than 90% pass rate for all cases using a gamma criteria of 3%/1 mm. CONCLUSIONS: The authors' experience demonstrates that the localization accuracy of the frameless image-guided system is comparable to robotic or invasive frame based radiosurgery systems.

Commissioning of the Varian TrueBeam linear accelerator: a multi-institutional study.

PURPOSE: Latest generation linear accelerators (linacs), i.e., TrueBeam (Varian Medical Systems, Palo Alto, CA) and its stereotactic counterpart, TrueBeam STx, have several unique features, including high-dose-rate flattening-filter-free (FFF) photon modes, reengineered electron modes with new scattering foil geometries, updated imaging hardware/software, and a novel control system. An evaluation of five TrueBeam linacs at three different institutions has been performed and this work reports on the commissioning experience. METHODS: Acceptance and commissioning data were analyzed for five TrueBeam linacs equipped with 120 leaf (5 mm width) MLCs at three different institutions. Dosimetric data and mechanical parameters were compared. These included measurements of photon beam profiles (6X, 6XFFF, 10X, 10XFFF, 15X), photon and electron percent depth dose (PDD) curves (6, 9, 12 MeV), relative photon output factors (Scp), electron cone factors, mechanical isocenter accuracy, MLC transmission, and dosimetric leaf gap (DLG). End-to-end testing and IMRT commissioning were also conducted. RESULTS: Gantry/collimator isocentricity measurements were similar (0.27-0.28 mm), with overall couch/gantry/collimator values of 0.46-0.68 mm across the three institutions. Dosimetric data showed good agreement between machines. The average MLC DLGs for 6, 10, and 15 MV photons were 1.33 ± 0.23, 1.57 ± 0.24, and 1.61 ± 0.26 mm, respectively. 6XFFF and 10XFFF modes had average DLGs of 1.16 ± 0.22 and 1.44 ± 0.30 mm, respectively. MLC transmission showed minimal variation across the three institutions, with the standard deviation <0.2% for all linacs. Photon and electron PDDs were comparable for all energies. 6, 10, and 15 MV photon beam quality, %dd(10)x varied less than 0.3% for all linacs. Output factors (Scp) and electron cone factors agreed within 0.27%, on average; largest variations were observed for small field sizes (1.2% coefficient of variation, 10 MV, 2 × 2 cm(2)) and small cone sizes (<1% coefficient of variation, 6 × 6 cm(2) cone), respectively. CONCLUSIONS: Overall, excellent agreement was observed in TrueBeam commissioning data. This set of multi-institutional data can provide comparison data to others embarking on TrueBeam commissioning, ultimately improving the safety and quality of beam commissioning.

TU-E-BRB-10: Dosimetric Consequences of Setup Errors Using CBCT for SBRT Localization.

PURPOSE: Steep dose gradients and high dose per fraction in stereotactic ablative radiation therapy (SABR or SBRT) necessitate highly accurate tumor localization. This study evaluates inter-fraction shifts, as defined by couch correction analysis, and investigates the effect of tumor location and internal target volume (ITV) on these shifts. In addition, residual errors associated with post-CBCT correction and their dosimetric consequences were quantified. METHODS: Daily free-breathing (FB) CBCT images used for daily localization of 78 patients with non-small cell lung cancer were retrospectively evaluated. Among the population, 39 patients also received pre-treatment kV images after CBCT alignment. ITV inter-fraction displacement was evaluated by matching the CBCT and the FB helical CT images, and setup errors were quantified using orthogonal kV images. Associations between ITV location and inter-fraction motion were studied by categorizing tumors into the following locations: chest-wall seated (CWS) and island, peripheral, central, or upper, middle and lower. Dosimetric consequences for the patient with the largest setup error were explored. RESULTS: ITV inter-fraction motion included the mean of the systematic error, ?inter=(-1.4, 2.0, 1.6) mm, standard deviation (SD) of the systematic error, Σinter=(2.1, 4.2, 2.9) mm, and SD of random errors, sinter=(2.2, 3.2, 3.6) mm. No significant associations were observed between inter-fraction shifts and tumor location or volume. Using CBCT for image guidance reduced the observed errors to µsetup=(-0.3, 0.1, 0.0) mm, Σsetup=(0.6, 0.6, 0.4) mm and ssetup=(1.2, 0.7, 0.7) mm. Dosimetric consequences for the patient with the largest setup error were explored. It was shown that a 3.0 mm setup margin was sufficient to provide greater than 95% dose coverage to the ITV. CONCLUSION: CBCT image guidance reduced setup errors significantly such that 2-3 mm, population-based, setup margins provided proper dose coverage to the ITV. Further investigation of inter-and intrafraction error classification by tumor location is warranted.

SU-E-J-45: Validation of the ExacTrac Virtual Isocenter Based Target Localization Method.

PURPOSE: With no stable landmarks available for localization, a 'virtual isocenter' "'or surrogate landmark near the target'" can be used for image guidance. However, using a virtual isocenter in ExacTrac has not been thoroughly validated. This study evaluates its target localization accuracy and investigates the impact of two different couch correction sequences. METHODS: A CT scan was acquired on an anthropomorphic thoracic phantom with a 2mm-diameter ball bearing (BB) marker implanted in thelung region. A treatment plan was created with isocenter placed at the BB center, and exported to ExacTrac. In ExacTrac, a virtual isocenter wasplaced on a spine vertebral body where three translational shifts (8.8cm laterally, 1.5cm longitudinally and 6cm vertically) were present. A series ofcouch rotations (+/-3 degrees, 1 degree increment) was intentionally applied to simulate angular setup variations. For each rotation, two stereoscopic x-rayimages were acquired and fused using the ExacTrac 6D registrationalgorithm. Calculated shifts were applied using two sequences: (1)automatic 5D corrections (three translations/two robotic couch rotations) followed by manual couch rotation; (2) manual couch rotation then automatic 5D corrections. After each ExacTrac localization, orthogonal (anterior-posterior and right-lateral) portal images were acquired to quantify BB center deviations from the radiation isocenter as an indicator of residual error. RESULTS: Minimal difference between investigated table correction sequences was observed. Average translational deviations between the BB and radiation isocenter (mean+/-1SD) were 0.3+/-0.3mm and 1.0+/-0.2mm for lateral and vertical axis respectively. Longitudinally, the deviations were 0.8+/-0.4mm from the anterior-posterior image and 0.1+/-0.3mm from the right-lateral image. The systematic difference (0.7+/-0.1 mm) between thetwo may have been attributed to gantry sagging during rotation. CONCLUSIONS: ExacTrac system successfully corrected angular shifts using the virtual isocenter method in a rigid phantom setup. The sequence ofcouch correction did not influence the localization accuracy. Further patient study is warranted.

SU-E-T-487: Spatial Assessment of Dose Distributions for Patients with Lung Cancer Treated with Stereotactic Ablative Radiotherapy (SABR).

PURPOSE: We hypothesize that PTV margin dose is an important factor for local tumor control. We evaluated dose distributions for patients originally treated with pencil-beam (PB)-based plans and retrospectively calculated with Monte Carlo (MC) method, with emphasis on the spatial region between the ITV and PTV (PTV-margin), where the largest dose differences were expected. METHODS: Forty-six stage I-II lung cancer patients with 51 lesions treated with SABR were retrospectively analyzed (23 central and 28 peripheral tumors). All patients received 4DCT imaging, and an ITV was generated from the maximum intensity projection and subsequent review of four 4DCT phases. An isotropic 3mm ITV-to-PTV margin was used. The iPlan TPS was used to generate the original treatment plans using PB-based heterogeneity correction. MC doses were recalculated using the same MUs as in the PB plan. Dose distributions for the ITV, PTV-margin, and PTV were analyzed using generalized equivalent uniform dose (gEUD) with a = - 20. Student's paired t-test elucidated differences between PB and MC-based gEUD and the two different tumor locations. RESULTS: Mean ITV and PTV volumes were 24.2 cc (range: 2.2 to 99.3 cc) and 50.4 cc (range: 6.4 to 229.7 cc), respectively. The mean gEUDs of ITV, PTV-margin and PTV, normalized to PB-based 100% isodose were 1.02+/-0.04, 1.01+/-0.04 and 1.01+/-0.04 for PB-based plans, compared to 0.94+/-0.06, 0.88+/-0.08 and 0.90+/-0.08 (all p<0.05) for MC-based plans. The maximum overestimations with the PB algorithm in the PTV-margin average dose were 10.4% and 19.6% (p < 0.05) for peripheral tumor cases and central tumor cases, respectively. CONCLUSIONS: PB-based dose distributions showed the highest dose overestimation (relative to MC) in the PTV-margin spatial region. Analysis of spatial dose differences is an important precursor toward assessment of patterns-of-local failure, to be investigated in future work to explore possible association between dose and regions of failure. Acknowledgement: supported in part by grants from NIH R01 CA106770 and from Varian Medical Systems.

SU-E-J-59: Dual Imaging Guided Localization System for Spine Radiosurgery.

PURPOSE: To compare localization accuracies between an ExacTrac and cone beam computed tomography (CBCT) systems for single fraction spine adiosurgery. The work also aimed to evaluate the inherent systematic deviation of both ExacTrac and CBCT systems to achieve highly accurate localization in the spine radiosurgery. METHODS: ExacTrac and CBCT imaging systems were evaluated using the linac isocenter as the mutual reference point. First, a BB was placed in an anthropomorphic pelvic phantom. The phantom was localized with both imaging systems and the procedure was repeated 12 times. These results were used to devise a localization protocol using both imaging systems in spine radiosurgery, and employed for 51 patients (81 isocenters) prescribed for single fraction treatment. The displacement discrepancy between the isocenter and two systems were quantified in four dimensions (three translations, one rotation). A Student's two-tailed t-test was used to test for significant differences between the two imaging systems. RESULTS: The phantom study showed 1.4±0.5, 0.6±0.5, and 0.1±0.5 mm differences between the two imaging systems in the anterior/posterior (A/P), superior/inferior (S/I) and left/right (L/R) directions, respectively. The angular difference was minimal along all three axes. The patient study revealed similar isocenter discrepancies between ExacTrac and CBCT of 1.1 ± 0.7 mm, 1.0±0.9 mm, and 0.2±0.9 mm in the A/P, S/I, and L/R directions, respectively, with the A/P and S/I directions showing statistical significance ((t(80) = 13.5 and 7.6 respectively, p = 0.000). The couch yaw discrepancy was 0 ± 0.3°. Overall, 1 mm systematic differences were observed in the A/P and S/I directions between ExacTrac and CBCT localization systems, both in phantom and patient. A procedure was developed to mitigate this systematic discrepancy. CONCLUSIONS: These findings have justified our patient localization tolerance levels of 2 mm translation and 1 degree rotation for spine SRS treatment.

SU-E-T-197: A Comprehensive Variance Reporting System and an Analysis of Variances Reported at Our Institution.

PURPOSE: It is essential for radiation oncology departments to have comprehensive patient safety and quality programs. Two years ago we undertook a systematic review of our safety/QA program. Existing policies were updated and new policies created where necessary. One crucial component of any safety/QA program is continually updating it based on current information, the 'check' and 'act' portions of the Deming Cycle. We accomplished this with a transparent variance reporting system and a safety/QA committee reviewing and acting on reported variances. METHODS: With 5 radiation oncology centers in our institution, we needed to devise a system that would allow anyone to report a variance and provide our QA committee the ability to review variances system-wide. We developed the system using web-based tools. The system allows individuals to report variances, anonymously or named, specify the nature of the variance and indicate the tools used to identify the variance. RESULTS: In 2011, 285 variances were reported, 102 were reported by physicists, 86 anonymously, 71 by therapists and 26 by dosimetrists. We realized the need to develop clear classifications for variances. We added a high priority category, defined as variances which resulted in or had the potential to result in harm to a patient or when a policy is purposely overridden. Of the 285 variances reported, 5 were high priority. We created a process variance category, defined as variances where a specific clinical process is not followed. Of the 285 reported variances 155 were process variances. CONCLUSIONS: Reporting of variances through a centralized database is central toward developing a robust patient safety/quality assurance program. Anonymous reporting fosters a non-punitive environment, and promotes the 'safety culture'. The goal of such a system is to review trends in clinical processes and ultimately to improve safety/quality by reducing variances associated with these processes.

Successful application of tissue-engineered skin to refractory ulcers.

In this study, the effectiveness of a tissue-engineered skin (Activskin; Aierfu, Xi'an, China) was evaluated for the treatment of various refractory ulcers. These ulcers were treated with Activskin after debridement and irrigation with saline. A second application of Activskin was essential if the first application failed to persist on the wounds. Clinical efficacy and safety were assessed at regular clinic visits during 6 months of follow-up. All 11 treated patients improved with Activskin. The ulcers healed by inward migration from the wound edge. The average healing time was 27.8 days. No recurrent ulceration or other adverse events were observed during follow-up. These results provide preliminary evidence that Activskin is safe and effective in the management of refractory ulcers.

Three types of defense-responsive genes are involved in resistance to bacterial blight and fungal blast diseases in rice.

Bacterial blight and fungal blast diseases of rice, caused by Xanthomonas oryzae pv. oryzae and Pyricularia grisea Sacc., respectively, are two of the most devastating diseases in rice worldwide. To study the defense responses to infection with each of these pathogens, expression profiling of 12 defense-responsive genes was performed using near-isogenic rice lines that are resistant or susceptible to bacterial blight and fungal blast, respectively, and rice cultivars that are resistant or susceptible to both pathogens. All 12 genes showed constitutive expression, but expression levels increased in response to infection. Based on their expression patterns in 12 host-pathogen combinations, these genes could be classified into three types, pathogen non-specific (6), pathogen specific but race non-specific (4) and race specific (2). Most of the 12 genes were only responsive during incompatible interactions. These results suggest that bacterial blight and fungal blast resistances share common pathway(s), but are also regulated by different defense pathways in rice. Activation of the corresponding R gene is the key step that initiates the action of these genes in defense responses. The chromosomal locations and pathogen specificities of seven of the 12 genes were consistent with those of previously identified quantitative trait loci for rice disease resistance, which indicates that some of the 12 genes studied may have a phenotypic impact on disease resistance in rice.

[Study of low-fusing porcelain fused to Ti-75 alloy].

OBJECTIVE: To study the feasibility of low-fusing porcelain fused to Ti-75 alloy. METHODS: The bond strength and interfacial state of porcelain-titanium were observed by EPM analysis and shear test. RESULTS: The results showed that the shear bond strength of low-fusing porcelain fused with Ti-75 alloy and the conventional porcelain fused to base metal alloy (NC-VMK68) respectively were 47.38 +/- 7.95 MPa and 48.50 +/- 7.60 MPa. There were no significant difference in the shear bond strength between the two results (P > 0.05). The analysis of electron microprobe showed that there was no crack in the interface, the low-fusing porcelain permeated Ti-75 alloy fairly, and titanium diffused from Ti-75 alloy to porcelain, and silicon, stannum diffused from porcelain to Ti-75 alloy. CONCLUSION: Ti-75 alloy can be regarded as a suitable alloy for low-fusing porcelain.

[The influential factors on DNA cycle sequencing and data evaluation of practical example].

OBJECTIVE: To study some factors that may influence DNA sequencing by analyzing 2040 sequencing samples retrospectively. METHODS: The effects of DNA templates, primers, cycle sequencing reactions as well as purification methods were comparatively analyzed. RESULTS: 70 percent of sequencing failure is caused by DNA template. Characteristics of data from poor template preparation include top-heavy with a short read length, acceptable signal with some noise peaks (Ns), weak signal, overall noise and flat lines or no signal. The ineffective primers can cause 15.4 percent sequencing failure. Possible explanations include primer mismatches and low Tm value. CONCLUSIONS: The quality of template DNA can have a major impact on the quality of the DNA sequencing. Purification of the extension products is absolutely necessary in DNA sequencing, and isopropanol precipitation is highly recommended for this procedure.

Three-dimensional biomechanical properties of the human cervical spine in vitro. I. Analysis of normal motion.

Our aim was to determine the biomechanical properties of the normal human cervical spine under physiological static loads. The three-dimensional displacements under three pure moments: flexion-extension, left-right lateral bending and left-right axial torsion--were measured in 56 intact functional spinal units (FSUs) taken from between C2 and C7 in 29 human cadavers. For each mode of loading, load-displacement curves were plotted. Then we calculated each neutral zone, range of motion, neutral zone ratio, ratio of coupled motion, limit moment and secant stiffness. The effects of intervertebral disc degeneration and the disc level were also taken into account by the analysis of variance. Our results adequately demonstrated both the non-linearity of load-displacement curves and the neutral zone of the cervical spine in three-dimensional space. At the same time, we found statistically that the stiffness in the three planes are significantly different, as are the stiffnesses in lateral bending of successive different FSUs. However, significant differences of stiffness in different states of disc degeneration were only found in right lateral bending. There were significant differences between levels in ratio of coupled motion under both lateral bending and axial torsion. The loading cycle conditions and the biomechanical responses of principal motion of C1-2 are also reported.

Three-dimensional biomechanical properties of the human cervical spine in vitro. II. Analysis of instability after ligamentous injuries.

We wanted to determine the biomechanical properties of the human cervical spine with ligamentous injuries. The three-dimensional displacements under four pure moments--flexion, extension, left-right lateral bending and left-right axial torsion--were measured in 18 functional spinal units (FSUs) taken from 9 human cadaveric cervical spines. The experimentation was first performed with intact FSUs, then a series of ligamentous injuries were artificially created. The same measurements for the same FSUs were repeated after each step of ligamentous injury. For each mode of loading and each step of injury, three-dimensional load-displacement curves were plotted. From these curves, we calculated the following parameters for the principal motion: the neutral zone, the range of motion and the flexibility coefficients. A statistical analysis of these parameters was performed between intact FSUs and different ligamentous injury situations. The analysis of ligamentous injuries shows the consequences of different ligamentous injuries and will help us to assess certain assumptions about clinical stability.

Fusion of low-fusing porcelain to Ti-75 alloy: an experimental study.

OBJECTIVE: To study the stomatological feasibility of low-fusing porcelain fused to Ti-75 alloy. METHODS: Electroprobemicroanalysis (EPMA) and shear test were used to observe interface state and bonding strength of porcelaintitanium. RESULTS: Shear bond strengths of low-fusing porcelain with Ti-75 alloy and conventional porcelain each fused to metal (NC-VMK68) were 47.38 +/- 7.95 MPa and 48.50 +/- 7.60 MPa, respectively. There was no significant difference between the shear bonding strength of low-fusing porcelain with Ti-75 and that of conventional porcelain fused to metal (PFM) (P > 0.05). EPMA showed that Ti-75 alloy and low-fusing porcelain bound tightly, had no fissure, and that low-fusing porcelain had good infiltration to Ti-75. It was shown that Ti spread from Ti-75 basal body into porcelain, and elements such as Si-Sn spread from porcelain to Ti-75. CONCLUSION: Ti-75 alloy can be used stomatologically, as a porcelain alloy.

Atherosclerosis of the carotid artery: evaluation by magnetic resonance angiography.

Carotid artery atherosclerotic plaques (APs) can lead to brain ischemia, an event shown to correlate with both the degree of stenosis and the composition of the AP. Currently, accurate estimates of stenosis can be obtained by either x-ray angiography or three-dimensional time-of-flight (TOF) magnetic resonance angiography (MRA). Our purpose was to determine whether three-dimensional TOF MRA images could also provide information on plaque location, morphology, and composition. Seven pre-endarterectomy patients underwent three-dimensional TOF MRA. After endarterectomy, plaque histology was evaluated. Three-dimensional TOF MRA images contained sufficient soft tissue contrast to differentiate the plaques from the surrounding tissues in all cases. Estimation of plaque morphology had 80% correlation with histology. Finally, intraplaque hemorrhage and calcification were deplicted as regions of moderately high and very low intensity, respectively. These preliminary results suggest that three-dimensional TOF MRA may be useful in studying the development and progression of carotid atherosclerosis.