Clinical anatomy and 3D virtual reconstruction of the lumbar plexus with respect to lumbar surgery

Background

Exposure of the anterior or lateral lumbar via the retroperitoneal approach easily causes injuries to the lumbar plexus. Lumbar plexus injuries which occur during anterior or transpsoas lumbar spine exposure and placement of instruments have been reported. This study aims is to provide more anatomical data and surgical landmarks in operations concerning the lumbar plexus in order to prevent lumbar plexus injuries and to increase the possibility of safety in anterior approach lumbar surgery.

Methods

To study the applied anatomy related to the lumbar plexus of fifteen formaldehyde-preserved cadavers, Five sets of Virtual Human (VH) data set were prepared and used in the study. Three-dimensional (3D) computerized reconstructions of the lumbar plexus and their adjacent structures were conducted from the VH female data set.

Results

The order of lumbar nerves is regular. From the anterior view, lumbar plexus nerves are arranged from medial at L5 to lateral at L2. From the lateral view, lumbar nerves are arranged from ventral at L2 to dorsal at L5. The angle of each nerve root exiting outward to the corresponding intervertebral foramen increases from L1 to L5. The lumbar plexus nerves are observed to be in close contact with transverse processes (TP). All parts of the lumbar plexus were located by sectional anatomy in the dorsal third of the psoas muscle. Thus, access to the psoas major muscle at the ventral 2/3 region can safely prevent nerve injuries. 3D reconstruction of the lumbar plexus based on VCH data can clearly show the relationships between the lumbar plexus and the blood vessels, vertebral body, kidney, and psoas muscle.

Conclusion

The psoas muscle can be considered as a surgical landmark since incision at the ventral 2/3 of the region can prevent lumbar plexus injuries for procedures requiring exposure of the lateral anterior of the lumbar. The transverse process can be considered as a landmark and reference in surgical operations by its relative position to the lumbar plexus. 3D reconstructions of the lumbar plexus based on VCH data provide a virtual morphological basis for anterior lumbar surgery.

Comparison of different semi-empirical algorithms to estimate chlorophyll-a concentration in inland lake water

Based on in situ water sampling and field spectral measurement from June to September 2004 in Lake Chagan, a comparison of several existing semi-empirical algorithms to determine chlorophyll-a (Chl-a) content was made by applying them to the field spectra and in situ chlorophyll measurements. Results indicated that the first derivative of reflectance was well correlated with Chl-a. The highest correlation between the first derivative and Chl-a was at 680 nm. The two-band model, NIR/red ratio of R710/670, was also an effective predictor of Chl-a concentration. Since the two-band ratios model is a special case of the three-band model developed recently, three-band model in Lake Chagan showed a higher resolution. The new algorithm named reverse continuum removal relies on the reflectance peak at 700 nm whose shape and position depend strongly upon chlorophyll concentration: The depth and area of the peak above a baseline showed a linear relationship to Chl-a concentration. All of the algorithms mentioned proved to be of value and can be used to predict Chl-a concentration. Best results were obtained by using the algorithms of the first derivative, which yielded R2 around 0.74 and RMSE around 6.39 μg/l. The two-band and three-band algorithms were further applied to MERIS when filed spectral were resampled with regard to their center wavelengths. Both algorithms showed an adequate precision, and the differences on the outcome were small with R2=0.70 and 0.71.

Heritability estimates and linkage analysis of 23 short tandem repeat loci on chromosomes 2, 11, and 12 in an endemic osteochondropathy in China

OBJECTIVE

To estimate the heritability of Kashin-Beck disease (KBD) in first-degree relatives and to identify chromosome regions likely to contain susceptibility loci for KBD.

METHODS

A total of 331 probands with confirmed KBD in their pedigrees were selected from 9331 residents in 17 KBD villages of Linyou county, northwestern China. The heritability (h(2)) in first-degree relatives was estimated by using Falconer's formula. The segregation ratio was calculated by the Li-Mantel-Gart method. A total of 23 short tandem repeat (STR) loci on chromosomes 2, 11, and 12 were used to identify the susceptibility genes for KBD by linkage analysis using the GENEHUNTER program in 19 KBD pedigrees.

RESULTS

The general prevalence rate of KBD was 13.75% in the 17 KBD villages, lower than that of 20.88% in the first-degree relatives of the KBD probands. In the first-degree relatives, the heritability was 0.064 and the segregation ratio 35.10% (p < 0.05). Slight evidence for heritability was detected only in locus D12S1725 with a logarithm of odds (LOD) score of 1.95. However, the nonparametric linkage (NPL) scores showed no linkage between KBD and the 23 loci; the maximum NPL score was 1.59 for locus D12S1725.

CONCLUSIONS

Our results show that 35.10% of the heritability is attributable to genetic variation for the KBD phenotype among individuals of Linyou county, and the segregation ratio supports a multifactorial inheritance of KBD. There is no significant linkage between KBD and the 23 markers in the Linyou population examined; however, markers near the locus D12S1725 may indicate loci for further study.

Adverse health effects of lead exposure on children and exploration to internal lead indicator

Our research on adverse effects of lead exposures on physical and neurobehavioral health of children aged 6-12years in 4 villages, labeled as K, M, L, and X, in rural China, was reported in this article. Lead in blood (PbB), urine (PbU), hairs (PbH), and nails (PbN) were measured by graphite furnace atomic absorption spectrometry. Abbreviated Symptom Questionnaire of Conner's instruments and Revised Raven's Standard Progressive Matrices were applied to evaluate childhood attention deficit/hyperactivity disorders (ADHD) and intelligences. Geometric means (SD) of PbB, PbU, PbH and PbN concentrations were 71.2 microg/L (1.56), 11.7 microg/g (1.75), 12.5 microg/g (2.82), and 25.3 microg/g (2.79), respectively. 54 (17.0%) children had PbB levels of > or =100 microg/L. Boys, 6-10 years old, and living in village K were 2.11, 2.48, and 9.16 times, respectively, more likely to be poisoned by lead than girls, aged 11-12 years, and residing in X. 18 (5.7%) and 37 (11.7%) subjects had ADHD and mental retardations, respectively. Inverse relationships between intelligences and natural log transformed PbU and PbH levels were observed with respective odds ratios (95%CI) of 1.79 (1.00-3.22) and 1.46 (1.06-2.03) or 1.28 (1.04-1.58) and 1.73 (1.18-2.52) by binary or ordinal logistic regression modeling. ADHD prevalence was different by gender and age of subjects. PbU, PbH, and PbN related to PbB positively with respective correlation coefficients of 0.530, 0.477, and 0.181. Receiver operating characteristic (ROC) curves of the three measurements revealed areas under curves (AUCs) being 0.829, 0.758, and 0.687, respectively. In conclusion, children had moderate levels of lead exposures in this rural area. Intelligence declines were associated with internal lead levels among children. ROC analysis suggests PbU an internal lead indicator close to PbB.

Application of navigation template to fixation of sacral fracture using three-dimensional reconstruction and reverse engineering technique

OBJECTIVE

To provide a new method in the fixation of sacral fracture by means of three-dimensional reconstruction and reverse engineering technique.

METHODS

Pelvis image data were obtained from three-dimensional CT scan in patients with sacral fracture. The data were transferred into a computer workstation. The three-dimensional models of pelvis were reconstructed using Amira 3.1 software and saved in STL format. Then the three-dimensional fracture models were imported into Imageware 9.0 software. Different situations of reduction (total reduction, half reduction and non-reduction) were simulated using Imageware 9.0 software. The best direction and location of extract iliosacral lag screws were defined using reverse engineering according to these three situations and navigation templates were designed according to the anatomic features of the postero-iliac part and the channel. The exact navigational template was made by rapid prototyping. Drill guides were sterilized and used intraoperatively to assist in surgical navigation and the placement of iliosacral lag screws.

RESULTS

Accurate screw placement was confirmed with postoperative X-ray and CT scanning. The navigation template was found to be highly accurate.

CONCLUSION

The navigation template may be a useful method in minimal-invasive fixation of sacroiliac joint fracture.

Genetic and temporal dynamics of human immunodeficiency virus type 1 CRF07_BC in Xinjiang, China

To explore the temporal genetic variation of human immunodeficiency virus type 1 CRF07_BC and reconstruct its epidemic in Xinjiang, China, we studied 216 C2–V4 fragments of env genes sampled from 1996 to 2008. Phylogenetic analysis indicates that the viruses prevailing in Xinjiang form a large monophyletic cluster and may have originated from a common ancestor. The epidemic in Xinjiang was probably established around 1995 (95 % confidence interval, 1994–1996). We noted an increased diversity of CRF07_BC over time, with a rapid evolutionary rate we estimated to be 8.3×10−3 substitutions per site per year in the env gene. After 5–6 years of the epidemic (1997–2002), the transmission rate of CRF07_BC in Xinjiang slowed down, although CRF07_BC infection remained at a high prevalence.

[Application of computed tomography angiography in visualize of latissimus dorsi myocutaneous flap transplantation]

OBJECTIVE

To evaluate the feasibility and clinical significance of the computed tomography angiography (CTA) for the latissimus dorsi muscle (LDM) flap transplantation.

METHODS

From September 2007 to August 2008, 3 cases of soft tissue defects in limbs were treated with LDM flap transplantation. Three patients included 2 males and 1 female who were 23- to 42-years-old. All of soft tissue defects were caused by trauma. The locations were the forearm in 2 cases and the leg in 1 case. The area of defect was 17 cm x 8 cm-20 cm x 10 cm. All cases received CTA to observe the distribution and anastomosis of thoracodorsal artery. Subsequently, three-dimensional computer reconstruction were carried out to display the stereoscopic structure of the LDM flap and to design the LDM flap before operation.

RESULTS

The anatomy characteristic of LDM flap can be displayed accurately by the three-dimensional reconstruction model. The distribution of thoracodorsal artery in 3 cases of flaps was in concordance with preoperative design completely. All the flaps were excised successfully, the area of the flap was 19 cm x 10 cm-22 cm x 12 cm. All the transferred flaps survived completely. All cases were followed up from 4 months to 12 months. The color and texture of the flaps were good.

CONCLUSION

The three-dimensional reconstructive images can provide visible, stereoscopic and dynamic anatomy for clinical application of LDM flap. The digitized three-dimensional reconstructive models of LDM flap structures can be applied in clinical training and pre-operative design.

Novel hyperspectral reflectance models for estimating black-soil organic matter in Northeast China

This paper presents a novel method for estimating black-soil organic matter (SOM) in the black-soil zone of northeast China from hyperspectral reflectance models. Traditional black-soil property measurements are relatively slow, but the pressures of agricultural production and environmental protection require a quick method to collect black-soil organic matter content. SOM estimation using soil hyperspectral reflectance models can meet this requirement, based on the spectral characteristics of black-soil in Northeast China. On the basis of the spectral reflectance and its derivatives, hyperspectral models can be built using correlation analysis and multivariable statistical methods. The concepts of curvature and ratio indices are also applied to compare and test the stability and accuracy of data modeling. The results show that the response of black-soil spectral reflectance from 400-1,100 nm to organic matter content is more marked than that from 1,100-2,500 nm. Specifically, the main response range of black-soil organic matter is between 620-810 nm, with a maximal spectral response at 710 nm. By comparing different models, we found that the normalized first derivate model is optimal for estimating SOM content, with a determination coefficient of 0.93 and root mean squared errors (RMSE) of 0.18%.

Change detection of sandy land areas in Minfeng oasis of Xinjiang, China

In recent years, much attention has been given to desertification in Xinjiang, China, particularly in the southern edge of the Taklimakan Desert. In this study, an oasis in Minfeng County, which is located in the southern edges of the Taklimakan Desert, was chosen as our case study area. Supervised classification for land types was conducted, and then the change detection and the trend of changes in sandy land areas were analyzed and compared. The results show that the area of sandy land has decreased in the region in the period of 1992-2001. The main change was between sandy land and sparse vegetation in the Desert-oasis ecotone. In addition, the change from woodland to grassland and/or arable land was quite obvious from 1992 to 2001. These changes would probably result in more fragile environment and higher potentiality in land desertification in the area.

[Three-dimensional reconstruction technique in gastrocnemius flap surgery: initial clinical application]

OBJECTIVE

To discuss the experience with three-dimensional reconstruction technique in initial clinical application in gastrocnemius muscle flap surgery.

METHOD

From 2007 to 2008, 7 patients received gastrocnemius muscle flap surgeries to repair the wounds. Preoperative CT angiography or magnetic resonance imaging (MRI) was performed after injection of the contrast media for individualized three-dimensional gastrocnemius muscle flap reconstruction using Amira4.1 software. According to the size of the defect in the wound, individualized three-dimensional gastrocnemius muscle flap was designed and harvested from the posterior leg.

RESULTS

Individualized three-dimensional reconstruction of the gastrocnemius flap was performed in 7 cases, and the reconstructed flaps clearly displayed the blood vessels, skin and the adjacent three-dimensional structures. In 6 cases the main perforating branched and trunk of the blood vessels in the designed flap were consistent with the surgical findings; in 1 case, the perforating branches failed to be clearly displayed in the designed flap, and surgical examination identified perforating branches with an average diameter of 0.5 mm (minimally 0.3 mm). The flaps survived in all the 7 cases.

CONCLUSIONS

Three-dimensional reconstruction of the gastrocnemius flap based on the lower limb CT angiography or MRI allows three-dimensional observation of the anatomy of the flap and accurate marking of the extent of the flap to be harvested, therefore avoiding intraoperative injuries to the blood vessels to better survival of the flaps.

Selected Stro-1-enriched bone marrow stromal cells display a major suppressive effect on lymphocyte proliferation

Mesenchymal stem cells (MSCs) have an immunosuppressive effect and can inhibit the proliferation of alloreactive T cells in vitro and in vivo. Cotransplantation of MSCs and hematopoietic stem cells (HSCs) from HLA-identical siblings has been shown to reduce the incidence of acute graft-vs.-host disease. MSCs are heterogeneous and data on the inhibitory effects of different MSC subsets are lacking. The antigen Stro1 is a marker for a pure primitive MSC subset. We investigated whether Stro-1-enriched induce a more significant suppressive effect on lymphocytes in a mixed lymphocyte reaction (MLR), and whether this action is related to a specific gene expression profile in Stro-1-enriched compared to other MSCs. We demonstrated that the Stro-1-enriched population elicits a significantly more profound dose-dependent inhibition of lymphocyte proliferation in a MLR than MSCs. One thousand expanded Stro-1-enriched induced an inhibitory effect comparable to that of 10 times as many MSCs. Inhibition by Stro-1-enriched was more significant in contact-dependent cultures than in noncontact-dependant cultures at higher ratio. The Stro-1-enriched inhibitory effect in both culture types was linked to increased gene expression for soluble inhibitory factors such as interleukin-8 (IL-8), leukemia inhibitory factor (LIF), indoleamine oxidase (IDO), human leukocyte antigen-G (HLA-G), and vascular cell adhesion molecule (VCAM1). However, tumor growth factor-beta1 (TGF-beta) and IL-10 were only up-regulated in contact-dependant cultures. These results may support using a purified Stro-1-enriched population to augment the suppressive effect in allogeneic transplantation.

[Primary clinical result of digital template as navigation to supper cervical pedicle instrumentation]

OBJECTIVE

To observe the primary clinical result of digital template as navigation to the upper cervical pedicle instrumentation.

METHODS

CT scan of upper cervical vertebrae was performed. 3-D model of upper cervical vertebrae was reconstructed by software Amira 3.1 and was preserved in STL format. Then 3-D model was run in software UG Imageware 12.0, the best pedicle channel was extracted according to the reverse engineering principle. A virtual navigational template was established according to he lamina anatomic trait, and the best pedicle channel. The virtual vertebrae and navigational template were manufactured using rapid prototyping. The navigational template was sterilized and used intra operative to assist with the placement of pedicle screw. The Accuracy of screw placement was confirmed with postoperative X-ray and CT scanning.

RESULTS

The digital navigational template had been established and used in the 3 cases, the good trajectory of cervical pedicle had been showed by the CT scan of post operation. There were not complications of related pedicle screw insertion.

CONCLUSIONS

A novel method of upper cervical pedicle location using Reverse Engineering and rapid prototyping has been developed; the navigational template is found to be highly accuracy and has great expectation.

Land desertification monitoring and assessment in Yulin of Northwest China using remote sensing and geographic information systems (GIS)

The objective of this study is to develop techniques for assessing and analysing land desertification in Yulin of Northwest China, as a typical monitoring region through the use of remotely sensed data and geographic information systems (GIS). The methodology included the use of Landsat TM data from 1987, 1996 and 2006, supplemented by aerial photos in 1960, topographic maps, field work and use of other existing data. From this, land cover, the Normalised Difference Vegetation Index (NDVI), farmland, woodland and grassland maps at 1:100,000 were prepared for land desertification monitoring in the area. In the study, all data was entered into a GIS using ILWIS software to perform land desertification monitoring. The results indicate that land desertification in the area has been developing rapidly during the past 40 years. Although land desertification has to some extent been controlled in the area by planting grasses and trees, the issue of land desertification is still serious. The study also demonstrates an example of why the integration of remote sensing with GIS is critical for the monitoring of environmental changes in arid and semi-arid regions, e.g. in land desertification monitoring in the Yulin pilot area. However, land desertification monitoring using remote sensing and GIS still needs to be continued and also refined for the purpose of long-term monitoring and the management of fragile ecosystems in the area.

Mismatch repair gene mutations in Chinese HNPCC patients

To explore the characteristics of DNA mismatch repair gene mutations in Chinese patients with hereditary non-polyposis colorectal cancer (HNPCC) or Lynch syndrome, the MLH1 and MSH2 genes from probands of 76 HNPCC families were sequenced. By doing so, two frame-shift mutations, three splice-site mutations and fourteen missense mutations (thirteen missense mutations and one nonsense mutation) were identified in the MLH1 gene. In addition, one splice-site mutation and six missense mutations were detected in the MSH2 gene. None of these mutations were detected in 100 matched healthy controls. The remaining mutation-negative cases were subjected to large fragment deletion analysis using multiplex ligation-dependent probe amplification (MLPA). By doing so, five large fragment deletions were detected in the MSH2 gene. No large fragment deletions were detected in the MLH1 gene. We conclude that the MLH1 and MSH2 genes in Chinese HNPCC families exhibit broad mutation spectra.

Flocculation behavior and mechanism of an exopolysaccharide from the deep-sea psychrophilic bacterium Pseudoalteromonas sp. SM9913

Flocculation behavior and mechanism of the exopolysaccharide secreted by Pseudoalteromonas sp. SM9913 (EPS SM9913), a psychrophilic bacterium isolated from 1855m deep-sea sediment, has been studied in this paper. EPS SM9913 showed a peak flocculating activity of 49.3 in 1g/L kaolin suspension with 4.55mmol/L CaCl2 and the optimum pH range of 5-8. It appears that the flocculating activity of EPS SM9913 was stimulated by Ca2+ and Fe2+. This study found that EPS SM9913 showed a better flocculation performance than Al2(SO4)3 at salinity of 5-100 per thousand or temperatures of 5-15 degrees C. In addition, this EPS was effective to flocculate several other suspended solids. The measured zeta-potentials, the size of flocs formed during the flocculation process and the surface profile of flocs revealed by scan electron micrograph suggest that bridging is the main flocculation mechanism of the studied EPS. Deacetylation of EPS SM9913 resulted in a significant decrease in its flocculating activity indicating that the large number of acetyl groups in EPS SM9913 played an important role in its flocculation performance.

Zirconia toughened alumina ceramic foams for potential bone graft applications: fabrication, bioactivation, and cellular responses

Zirconia toughened alumina (ZTA) has been regarded as the next generation orthopedic graft material due to its excellent mechanical properties and biocompatibility. Porous ZTA ceramics with good interconnectivity can potentially be used as bone grafts for load-bearing applications. In this work, three-dimensional (3D) interconnected porous ZTA ceramics were fabricated using a direct foaming method with egg white protein as binder and foaming agent. The results showed that the porous ZTA ceramics possessed a bimodal pore size distribution. Their mechanical properties were comparable to those of cancellous bone. Due to the bio-inertness of alumina and zirconia ceramics, surface bioactivation of the ZTA foams was carried out in order to improve their bioactivity. A simple NaOH soaking method was employed to change the surface chemistry of ZTA through hydroxylation. Treated samples were tested by conducting osteoblast-like cell culture in vitro. Improvement on cells response was observed and the strength of porous ZTA has not been deteriorated after the NaOH treatment. The porous 'bioactivated' ZTA ceramics produced here could be potentially used as non-degradable bone grafts for load-bearing applications.

Dynamic analysis of genetic diversity of gag and env regions of HIV-1 CRF07_BC recombinant in intravenous drug users in Xinjiang Uvghur Autonomous Region, China

The aim of this study was to investigate the genetic variation of HIV-1 CRF07_BC, the most prevalent circulating strain in intravenous drug users (IDUs) in China. We studied the diversity in the C2-V5 region of the HIV-1 env gene and in the p17-p24 region of the HIV-1 gag gene from the same samples in 12 IDUs who were divided into two groups according to the length of infection time. Two IDUs were longitudinally monitored from the time of seroconversion for 2-2.5 years. The viral divergence from the founder strain and the viral population diversity between sequential time points were analyzed in two men. The data show that the divergence of the env gene is higher than that of gag in general, while the diversity of the gag gene is sometimes higher than that of env during the course of HIV evolution. In addition, env and gag gene diversity increased over time. The observed patterns and associations may enhance our understanding of HIV-1 evolution.

Snow-cover environmental monitoring and assessment in Northeast China using passive microwave emission models

In this study, we present the application of the passive microwave emission models to snow-cover environment monitoring and assessment in Northeast China. The study employs the radiative transfer function and strong fluctuation theory to develop the models. We used the exponential form of a spherical symmetric correlation function to describe random permittivity fluctuations. From strong fluctuation, we then obtained the phase matrix and extinction coefficients of snow-packs for the spherical symmetric correlation function. We also used the vector radiative transfer formula for the layer of a random medium by solving Gaussian quadrature and eigen analysis. By comparing the brightness temperatures at 5, 10.7, 18, and 37 GHz, the modelling results agreed with experimental data of dry-snow physical parameters as measured in the fieldwork.

High HIV risk among Uigur minority ethnic drug users in northwestern China

OBJECTIVE

To assess differences of HIV risk between ethnicities in northwestern China.

METHOD

Cross-sectional serosurvey and structured questionnaire interview of 383 injection drug users of either Han or Uigur ethnicity in Urumqi, Xinjiang.

RESULTS

Both Uigur minority ethnicity and residence in a Uigur or mixed Uigur/Han community were independently associated with higher HIV risk.

CONCLUSION

HIV prevention programs should give special focus on minority ethnic drug users and their communities.

Analysis of putative N-linked glycosylation sites and variable region of envelope HIV-1 CRF07_BC recombinant in intravenous drug users in Xinjiang Autonomous Region, China

To investigate more closely the determinants of transmission and escape in HIV-1 internal proteins, we analyzed the characterization of putative N-linked glycosylation sites (PNGSs) and the variable loop of CRF07_BC recombinant human immunodeficiency virus type 1 (HIV-1), isolated from intravenous drug users (IDUs). We studied the characterization of PNGSs and the variable loop in the C1-C5 and V1-V4 regions of the HIV-1 env gene in 12 intravenous drug users (IDUs) who were divided into two groups according to the length of infection time. In addition, two IDUs were longitudinally monitored from the time of seroconversion for 1.5 and 2.5 years. The longitudinal characterization within the individuals on PNGSs and the variable loop in the C1-C5 and V1-V4 region were also observed. Based on the above analysis, we found that PNGSs and the variable loop appeared to increase over time within IDU transmission of CRF07_BC recombinant HIV-1. We argue that limited PNGSs and the length of variable loops may be involved in selective transmission and escape.

Geo-morphological changes of the Wanpingkou tidal system arising from the building of a sailing boat station in Rizhao of China

This paper examines a small tidal system in Wanpingkou, Rizhao of China. The tidal system was originally maintained by a balance of the natural interaction between tidal currents and waves. But this tidal system was diminishing by reclamation processes since the 1980s, especially in 2003 when a sailing boat station was built in the study area. To investigate the stability and development mechanism of the tidal system, its feasibility was evaluated before the sailing boat station was built. The erosion and deposition in and out of the tidal system was analyzed, forecasted and compared with the data from field monitoring. The results show that the tidal system would remain relatively stable, although its adjacent shoreline might change somewhat after the newly built sailing boat station. This change would also affect the coastal water and wetland environment in the study area. Further field monitoring in the area is still necessary.

Willingness of Chinese injection drug users to participate in HIV vaccine trials

BACKGROUND

Chinese injection drug users (IDUs) may be a proper candidate population for HIV vaccine trials.

OBJECTIVE

To evaluate willingness to participate (WTP) in HIV vaccine trials among Chinese IDUs.

METHODS

Questionnaire interviews were completed among 401 IDUs in Urumqi City in northwestern China in 2005.

RESULTS

Overall 74.3% of participants said that they would be definitely willing to participate in HIV vaccine trials, 17.7% were probably willing, 6.2% were probably not willing, and remaining 1.8% were definitely not willing to join. Multivariate logistic regression analysis demonstrated that WTP was positively associated with having ever had sex with a drug use partner (adjusted odds ratio [AOR]: 1.8; 95% confidence interval [CI]: 1.04, 3.2), sharing needle and syringe with a new drug use partner in the past 3 months (AOR: 3.8; 95% CI: 1.2, 11.7), perceived family support for participation (AOR: 7.4; 95% CI: 4.3, 12.7), and perceived vaccine protection against HIV infection (AOR: 16.1; 95% CI: 3.7, 70.8), and was negatively associated with perceived risk of social stigma and isolation for participation (AOR: 0.3; 95% CI: 0.2, 0.5).

CONCLUSIONS

The stated WTP in hypothetical HIV vaccine trials was high among Chinese IDUs. Further studies are needed to evaluate actual enrollment into the trials.

Chitosan nanofibers from an easily electrospinnable UHMWPEO-doped chitosan solution system

Conversion of natural biopolymer chitosan into nanofibers through electrospinning has significant usefulness in various biomedical applications, in particular, for constructing a biomimetic and bioactive nanofibrous artificial extracellular matrix for engineering various tissues. Here, we show that introduction of an ultrahigh-molecular-weight poly(ethylene oxide) (UHMWPEO) into aqueous chitosan solutions remarkably enhances the formation of chitosan nanofibrous structure and leads to much lower loading of the water soluble fiber-forming aiding agent of PEO down to 5 wt % as compared to previous high PEO loadings in the electrospun chitosan nanofibers. The excellent electrospinnability of the current formulation renders electrospinning of natural biopolymer chitosan a robust process for large-scale production of practically applicable nanofibrous structures.