Synthesis, characterization, and application of microbe-triggered controlled-release kasugamycin-pectin conjugate

The controlled and targeted release of pesticides with high water solubility has been a challenge for integrated pest management. In this paper, kasugamycin, an antibiotic broadly used in plant disease control, was covalently conjugated to pectin to form a kasugamycin-pectin conjugate by an amide bond. The conjugate was structurally characterized by Fourier transform infrared spectroscopy, ultraviolet spectrophotometry, and thermal gravimetric analysis. The results showed that the conjugate was stable over a wide range of pH and temperatures, as well as under UV irradiation. When incubated with Pseudomonas syringae pv. lachrymans, the conjugate could be activated, releasing the kasugamycin, which made it a promising controlled-release formulation of pesticide.

Interleukin 12B rs3212227 T > G polymorphism was associated with an increased risk of gastric cardiac adenocarcinoma in a Chinese population

Gastric cardiac adenocarcinoma (GCA) is one of common malignant tumors in the world. Multiple genes that play critical roles in inflammatory pathways probably are associated with GCA risk. We conducted a hospital-based case-control study to evaluate the genetic effects of functional single nucleotide polymorphisms (SNPs): interleukin 9 (IL9) rs31563 C > T, IL9 rs31564 G > T, IL10 rs1800872 T > G, IL12A rs2243115 T > G, IL12B rs3212227 T > G, and IL13 rs1800925 C > T on the development of GCA. Two hundred and forty-three GCA cases and 476 controls were recruited. Their genotypes were determined using a custom-by-design 48-Plex SNPscan kit. IL12B rs3212227 T > G polymorphism was associated with the increased risk of GCA. However, there was no significant association between the other five SNPs and GCA risk. Stratified analyses indicated that the risk of GCA associated with the IL12B rs3212227 T > G polymorphism was evident among female patients and patients who never smoked or consumed alcoholic drinks. These findings indicated that functional polymorphism IL12B rs3212227 T > G might correlate with GCA risk. However, our results were obtained with a limited sample size; the power of our analysis was low. Larger studies are required to confirm the current findings.

Mechanical force-induced specific MicroRNA expression in human periodontal ligament stem cells

It remains unclear how the expression of microRNAs (miRNAs) in human periodontal ligament stem cells (PDLSCs) might respond to mechanical stretch. To investigate specific miRNA expression in stretched PDLSCs, we used a Flexcell® FX-5000™ tension system to achieve external mechanical stimulation. Then, a custom-designed microarray assay was performed to investigate and describe the genome-wide differential expression of miRNAs in normal and stretched PDLSCs. Finally, we implemented integrative miRNA target prediction and network analysis approaches to construct an interaction network of the key miRNAs and their putative targets. We found that stretching induced morphological changes and increased alkaline phosphatase (ALP) activity, runt-related transcription factor 2 (RUNX2), osteocalcin (OCN), and bone sialoprotein (BSP) expression in PDLSCs. The microarray data showed that 53 miRNAs were differentially expressed with stretching. With an interaction network, we examined the connections between 10 selected key miRNAs and their putative target genes, which were related to mechanical force. The results from the interaction network provided a basis for postulating the functional roles of miRNAs in PDLSCs.

Preparation and characterization of enzyme-responsive emamectin benzoate microcapsules based on a copolymer matrix of silica–epichlorohydrin–carboxymethylcellulose

Novel enzyme-responsive emamectin benzoate microcapsules with remarkable loading ability and photo- and thermal stability were prepared for sustained crop protection.

Preparation and characterization of novel functionalized prochloraz microcapsules using silica-alginate-elements as controlled release carrier materials

Controlled release formulation of pesticides is an effective approach to achieve the desirable purpose of increasing the utilization of pesticides and reducing the environmental residuals. In this work, a novel functionalized microcapsule using silica cross-linked with alginate, and some beneficial elements to crops, was prepared. The microcapsules were structurally characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy. The results showed that the microcapsules had a high loading efficiency of prochloraz (about 30% w/w) and could effectively protect prochloraz against degradation under UV irradiation and alkaline conditions, showed sustainable release for at least 60 days, and also likely increased disease resistance due to the element on the surface. Given the advantages of the microcapsules, this delivery system may be extended to other photosensitive or pH-sensitive pesticides in the future.

Development and validation of an HPLC method for determination of Amikacin in water samples by solid phase extraction and pre-column derivatization

This work presents a rapid and sensitive high performance liquid chromatography method for the determination of amikacin in water samples with solid phase extraction and pre-column derivatization. Amikacin residue was extracted from water samples with solid phase extraction cartridge. Then the extraction solution was derivatized with 4-chloro-3,5-dinitrobenzotrifluoride in the presence of triethylamine at 70°C in 20 min. The amikacin derivative was separated on a C18 column and detected by application of UV detection at 238 nm. The limit of detection is 0.2 μg/L with a signal-to-noise ratio of 3 and linearity is established over the concentration range from 0 to 500.0 μg/L. Recoveries of the amikacin in three types of water samples are from 87.5 % to 99.6 % and RSDs are 2.1 %-4.5 %. This method can be used for the quantification of amikacin residues in water samples.

MRI evaluation of BBB disruption after adjuvant AcSDKP treatment of stroke with tPA in rat

The primary limitation of thrombolytic treatment of ischemic stroke with tissue plasminogen activator (tPA) is the hemorrhagic risk. We tested AcSDKP (N-acetyl-seryl-aspartyl-lysyl-proline), as an auxiliary therapeutic agent, to reduce blood-brain barrier (BBB) disruption in a combination tPA thrombolytic treatment of stroke. Wistar rats subjected to embolic stroke were randomly assigned to either the tPA monotherapy group (n=9) or combination of tPA and AcSDKP treatment group (n=9) initiated at 4 h after ischemia. Magnetic resonance imaging (MRI) measurements were performed before and after the treatments. Immunohistochemical staining and measurements were performed to confirm MRI findings. Longitudinal MRI permeability measurements with gadolinium-diethylenetriamine penta-acetic acid (Gd-DTPA) demonstrated that combination treatment of acute embolic stroke with AcSDKP and tPA significantly reduced BBB leakage, compared to tPA monotherapy, at 3 and 6 days (18.3±9.8 mm3 vs. 65.0±21.0 mm3, p<0.001) after the onset of stroke, although BBB leakage was comparable between the two groups prior to the treatments (6.8±4.4 mm3 vs. 4.3±3.3 mm3, p>0.18). The substantial reduction of BBB leakage observed in the combination treatment group was closely associated with reduced ischemic lesions measured by T2 maps (113.6±24.9 mm3 vs. 188.1±60.8 mm3, p<0.04 at 6 days). Histopathological analysis of the same population of rats showed that the combination treatment significantly reduced parenchymal fibrin deposition (0.063±0.059 mm2 vs. 0.172±0.103 mm2, p<0.03) and infarct volume (146.7±35.9 mm3 vs. 199.3±60.4 mm3, p<0.05) compared to the tPA monotherapy at 6days after stroke. MRI provides biological insight into the therapeutic benefit of combination treatment of stroke with tPA and AcSDKP 4h after onset, and demonstrates significantly improved cerebrovascular integrity with neuroprotective effects compared with tPA monotherapy.

Interleukin 17A rs4711998 A>G polymorphism was associated with a decreased risk of esophageal cancer in a Chinese population

Esophageal cancer is the eighth most common cancer and sixth leading cause of cancer-associated death worldwide. Besides environmental risk factors, genetic factors might play an important role in the esophageal cancer carcinogenesis. We conducted a hospital-based case-control study to evaluate the genetic effects of functional single nucleotide polymorphisms (SNPs) in the interleukin 17A (IL17A) gene on the development of esophageal cancer. A total of 380 esophageal squamous cell carcinoma (ESCC) cases and 380 controls were recruited for this study. The genotypes were determined using a custom-by-design 48-Plex SNPscan Kit. IL17A rs4711998 A>G polymorphism was associated with the decreased risk of ESCC. When the IL17A rs4711998 AA homozygote genotype was used as the reference group, the AG genotype was associated with a significantly decreased risk for ESCC (AG vs. AA: adjusted odds ratio 0.72, 95% confidential interval 0.53-0.98, P = 0.039). However, there was no significant association between the other five SNPs and ESCC risk. Stratified analyses indicated that a significantly decreased risk of ESCC associated with the IL17A rs4711998 A>G polymorphism was evident among younger patients and patients who never smoking or drinking. These findings indicated that functional polymorphism IL17A rs4711998 A>G might contribute to ESCC susceptibility. However, our results were obtained with a limited sample size; the power of our analysis was low. Future larger studies with more rigorous study designs of other ethnic populations are required to confirm current findings.

Determination of malondialdehyde in biological fluids by high-performance liquid chromatography using rhodamine B hydrazide as the derivatization reagent

Malondialdehyde (MDA) is a biomarker for lipid peroxidation, and studies of sensitive and selective analytical methods for it are very important for pathological research. The aim of this work was to develop and validate a novel HPLC method for the quantification of MDA in biological fluids using rhodamine B hydrazide (RBH) as the derivatization reagent. After pretreatment and derivatization in acid medium at 50 °C for 40 min, the RBH-derivatized MDA was separated on a Kromasil C18 column at 25 °C and detected by a fluorescence detector at excitation wavelength of 560 nm and emission wavelength of 580 nm. The results showed linearity in the range of 0.8-1500.0 nM with a detection limit of 0.25 nM (S/N = 3). The recovery of MDA from plasma and urine was 91.50 to 99.20%, with a relative standard deviation range of 1.45 to 3.26%. In comparison to other methods reported for the determination of MDA, the proposed method showed superiority in simplicity, more sensitivity, shorter derivatization time, and less interference. The developed method was applied to quantification of MDA in human biological fluids collected from five volunteers with a concentration range of 24.62-245.00 nM.

Application of a global reference for fetal-weight and birthweight percentiles in predicting infant mortality

OBJECTIVE

To determine whether the recently published A global reference for fetal-weight and birthweight percentiles (Global Reference) improves small- (SGA), appropriate- (AGA), and large-for-gestational-age (LGA) definitions in predicting infant mortality.

DESIGN

Population-based cohort study.

SETTING

The US Linked Livebirth and Infant Death records between 1995 and 2004.

POPULATION

Singleton births with birthweight >500 g born at 24-41 weeks of gestation.

METHODS

We compared infant mortality rates of SGA, AGA, and LGA infants classified by three different references: the Global Reference; a commonly used birthweight reference; and Hadlock's ultrasound reference.

MAIN OUTCOME MEASURES

Infant mortality rates.

RESULTS

Among 33 997 719 eligible liveborn singleton births, 25% of preterm and 9% of term infants were classified differently for SGA, AGA, and LGA by the Global Reference and the birthweight reference. The Global Reference indicated higher mortality rates in preterm SGA and preterm LGA infants than the birthweight reference. The mortality rate was considerably higher in infants classified as preterm SGA by the Global Reference but not by the birthweight reference, compared with the corresponding infants classified by the birthweight reference but not by the Global Reference (105.7 versus 12.9 per 1000, RR 8.17, 95% CI 7.38-9.06). Yet, the differences in mortality rates were much smaller in term infants than in preterm infants. Black infants had a particularly higher mortality rate than other races in AGA and LGA preterm and term infants.

CONCLUSIONS

In respect to the commonly used birthweight reference, the Global Reference increases the identification of infant deaths by improved classification of abnormal newborn size at birth, and these advantages were more obvious in preterm than in term infants.

Herpes simplex virus type 2 incidence and associated risk factors among female sex workers in a high HIV-prevalence area of China

Herpes simplex virus type 2 (HSV-2) can contribute to the spread of HIV. From March 2006 to November 2009, female sex workers (FSWs) in Yunnan, China were recruited into an open cohort study to determine incidence and risk factors for HSV-2 acquisition. Participants were interviewed and tested for HSV-2 and other sexually transmitted infections (STIs) every six months. A multivariate Cox proportional hazards regression model with time-dependent variables was used to measure associations with HSV-2 acquisition. In 3.5 years, 83 incident cases of HSV-2 infection were diagnosed, yielding an overall incidence of 21.9 per 100 person years (PY) (95% confidence interval [CI], 17.8-26.3). Working in higher risk commercial sex venues, current Neisseria gonorrhoeae infection, age of sexual debut <18 years and lack of a regular sex partner were independent factors associated with HSV-2 acquisition. The high incidence of HSV-2 suggests that prevention methods for HIV/STI control are urgently needed.

Production of S-acetoin from diacetyl by Escherichia coli transformant cells that express the diacetyl reductase gene of Paenibacillus polymyxa ZJ-9

S-acetoin (S-AC) is an important four-carbon chiral compound that has unique industrial applications in the asymmetric synthesis of valuable chiral specialty chemicals. However, previous studies showed that the usually low yield and optical purity of S-AC as well as the very high substrate cost have hindered the application of this compound. In the current work, a gene encoding diacetyl reductase (DAR) from a Paenibacillus polymyxa strain ZJ-9 was cloned and expressed in Escherichia coli. Whole cells of the recombinant E. coli were used to produce S-AC from diacetyl (DA). Under optimal conditions, S-AC with high optical purity (purity >99·9%) was obtained with a yield of 13·5 ± 0·24 and 39·4 ± 0·38 g l(-1) under batch and fed-batch culture conditions, respectively. This process featured the biotransformation of DA into S-AC using whole cells of engineered E. coli. The result is a considerable increase in the yield and optical purity of S-AC, which in turn facilitated the practical application of the compound.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study demonstrated a highly efficient new method to produce S-acetoin with higher than 99·9% optical purity from diacetyl using whole cells of engineered Escherichia coli. It will therefore decrease the production cost of S-acetoin and highlight its application in asymmetric synthesis of highly valuable chiral compounds.

Associations between drug use and risk behaviours for HIV and sexually transmitted infections among female sex workers in Yunnan, China

This is a cross-sectional study of 399 subjects conducted to explore the association between drug use and risk behaviour for HIV and sexually transmitted infections (STIs) among female sex workers (FSWs), and also to study the prevalence of HIV/STIs among drug-using FSWs (DUFSWs) and non-DUFSWs in Yunnan province of China. Demographic information, mobility, sexual and drug-using behaviours were collected and subjects were tested for HIV/STIs. Mean age was 27 years (SD = ±7.8) and 94 (23.6%) tested positive for recent opiate use. Compared with non-DUFSWs, DUFSWs had a significantly higher prevalence of HIV (38% versus 4%, P ≤ 0.001), herpes simplex virus type 2 (HSV-2; 92% versus 60%, P ≤ 0.001) and STIs (95.7% versus 69.2%, P ≤ 0.001). DUFSWs had a significantly longer duration of commercial sex work compared with non-DUFSWs (median 5 versus 1 years, P ≤ 0.001), and had at least two clients in the last working day. DUFSWs were also more likely to work in low-end commercial sex venues and frequented a greater number of work locations than non-DUFSWs. Compared with non-DUFSWs, DUFSWs were more likely to exhibit riskier sexual behaviours and greater workplace mobility. Interventions targeting drug-related behavioural changes are needed urgently in this population in order to reduce rates of HIV and STIs.

Molecular characterization and population genetic diversity of Limonium sinense based on nuclear ribosomal DNA and ISSR

The single nucleotide polymorphism (SNP) and amplification refractory mutation system (ARMS) have been applied to authenticate Limonium species and their corresponding herb samples. One species specific primer was designed and the amplification product is 200 bp (Limonium sinense) by using this primer. No band was observed with other Limonium species. The phylogenetic relationship of Limonium species were studied using ribosomal DNA ITS and the adulterants (L. bicolor, L. aureum and L. wrightii) were clustered with L. sinense in NJ tree. Inter simple sequence repeat (ISSR) was used to assess genetic diversity and population structure of L. sinense and a high level of genetic diversity was detected (H(E) = 0.2573, PPB = 85.71%) with POPGENE. Based on AMOVA analysis, there was moderate variation between pairs of populations with phi(ST) from 0.1744 to 0.5131 and on average 28.81% of the genetic variation occurred among populations. Five main clusters were shown in UPGMA dendrogram using TFPGA. The results showed that SNP and ARMS could be used to authenticate not only Limonium species but related herbs on rDNA internal transcribed spacer region. Possible strategies should be implemented for conservation of this endemic herb.

[Association between the myeloperoxidase gene polymorphisms and the susceptibility to prostate cancer: a case-control study in a Chinese population]

BACKGROUND AND OBJECTIVES

Prostate cancer (PCa) is the most common cancer among men in most western populations. The polymorphisms of the myeloperoxidase (MPO) gene have been correlated with abnormal MPO expression and increased risk of various types of cancers. Our study aimed to evaluate the association between the genetic polymorphisms and the risk of prostate cancer.

METHODS

Genotyping was carried out by using the genotyping system (MassARRAY iPLEX; Sequenom, Inc., San Diego, CA, USA) on 1,108 PCa patients and 1,525 cancer-free controls in a Chinese Han population.

RESULTS

Although one SNP (rs8082134, P < 0.050) was significant, it is very rare and unstable. Other SNPs had no significant difference between genotype distributions in the PCa patients and the control group. Totally, SNPs in the MPO gene is not associated with PCa risk.

CONCLUSION

Our data showed a limited association between the MPO SNPs and the susceptibility to PCa in population of Chinese Han population. The possible association of rs8082134 of MPO with PCa risk need further clarification.

Isolation and characterization of microsatellite markers in Chinese herb of Dendrobium loddigesii

As an invaluable herb, Dendrobium loddigesii is widely used in Chinese medicinal field. In order to develop a convenient and efficient identification method and investigate the genetic diversity and structure of this species, twelve microsatellite loci were isolated from two microsatellite-enriched libraries. Twenty-six individuals from Baise population were analysed. The observed and expected heterozygosities ranged from 0.174 to 0.617 and from 0.182 to 0.608, respectively. These microsatellite loci characterized from D. loddigesii will contribute to research on the individual authentication, population structure, genetic diversity and conservation of this species and its similar species.

SU-E-J-39: Minimizing IGRT Imaging Exposures: KV Radiograph Vs. KV-CBCT Vs. MV Portal Images

PURPOSE

To compare the IGRT doses from MV, kV and CBCT images.

METHODS

kV imaging systems integrated into Varian Trilogy and TrueBeam accelerators were modeled using BEAMnrc/DOSXYZnrc Monte Carlo codes and the dose to calibration phantoms for a variety of kV beams(kVp, bow-tie filters, etc.) were calculated. The doses to the same phantoms and kV beams were then measured experimentally using calibrated ion-chambers.The "calibrated" Monte Carlo kV beams were used to calculate dose to CT images of patients. Organ doses were analyzed using DVHs.

RESULTS

The doses to the prostate are 0.015 and 2.2cGy using AP kV and MV images; are 0.06 and 2.3cGy using lateral kV and MV images; and, are 1.7 cGy using CBCT images. For head and neck images, the doses to the eye are 0.08 and 0.001 cGy using AP and PA kV images; are 2.3 and 1.8cGy using AP and PA MV images; are 0.001 and 2.4cGy for lateral kV and MV images; and, are 0.2 cGy for CBCT images. For kV radiographs, organ doses can be further reduced, by over 30%, by using bow-tie filters. CBCT doses to the prostate are 1.6 and 0.9cGy for OBI and TrueBeam pelvis scans; a >40% dose reduction for the same image quality. For OBI CBCT head scans the doses to the eye and brain stem are 0.2 and 2.8cGy, respectively.

CONCLUSIONS

Due to the low penetration of kV beams,selecting beam angles so that the sensitive organs are near the beam exit, and/or using bow-tie filters, can substantially reduce organ doses when using kV radiographs. For daily positioning of pediatric brain patient with a set of orthogonal kV images, a CBCT scan, or a set of orthogonal MV images, the doses to the eyes are 0.1, 0.2, and 4.7 cGy, respectively.

SU-E-T-407: Freedom from Conventional: Application of RapidArc for SBRT Lung Treatments

PURPOSE

Stereotactic body radiotherapy (SBRT) has been applied in treating early stage small lung lesions, delivering hypofractionated doses in a conformai manner. Studies have shown that SBRT has similar outcomes compared with surgery. Conventionally, SBRT lung treatments rely on utilization of multiple small, conformai, static fields in coplanar and non- coplanar arrangements. With the advent of RapidArc, it is important to evaluate the differences in dosimetry and delivery of conformai SBRT lung treatments for both conventional static field and VMAT techniques.

METHODS

A retrospective study of 12 patients at our institution who have received SBRT for primary lung lesions was used to evaluate the application of RapidArc for such cases. Originally treated plans utilized eight to ten conformai static coplanar and non-coplanar fields. RapidArc plans were generated in Eclipse using single and multiple arc setups.

RESULTS

As an ntensity-modulated modality, RapidArc provides greater freedom as compared to conventional static field delivery, as one can achieve dose uniformity throughout the PTV or replicate the dosimetry synonymous with conventional SBRT. RapidArc is capable of reproducing the high conformality achieved by conventional SBRT; dual arc plans, delivering uniform dose distributions, yielded an average CI100% of 1.11 and D2cm maximum of 63% of the prescribed dose, compared to 1.33 and 77% (p- values of .002 and .005, respectively) for conventional SBRT. Application of a short, non-coplanar arc, in conjunction with dual coplanar arcs, improved sparing of OARs in direct proximity of the PTV at the expense of treatment time. RapidArc allows for faster treatment delivery; conventional SBRT delivery averages 13.7 minutes at our institution, whereas coplanar dual arcs are estimated to average treatment durations of 4.2 minutes.

CONCLUSIONS

RapidArc is capable of generating conformai dose distributions and sparing of OARs, allows greater freedom in plan optimization, and reduces treatment time significantly.

SU-E-T-195: Experience in Implementing Intraoperative Radiation Therapy for Accelerated Partial Breast Irradiation Using Low-Energy X-Ray Source

PURPOSE

To present our preliminary experience and quality-assurance (QA) procedures in implementing intraoperative-radiation therapy (IORT) for accelerated-partial-breast irradiation (APBI) using the Axxent-system controller (Xoft Inc.) Methods: IORT was implemented in our institution utilizing a 50-keV x-ray source. APBI allows breast conserving in patients with early-stage-breast cancer by delivering radiation to the lumpectomy bed via an applicator balloon filled with water, to which a prescribed dose of 20 Gy was applied to its surface. In-situ anesthesiology, breast-surgery and radiation-oncology teams were required to achieve this procedure. Calibration of the source, including temperature and pressure corrections, was performed by the controller resulting in a calibration factor, which was manually introduced by a physicist into an in-house program providing the corrected dwell times. Evaluation of exposure measurements determined that personnel standing behind glass-rolling shields during irradiation were sufficient protection.

RESULTS

We have successfully treated four patients to date. Surgical times averaged about two hours, QA and setup of controller took about 30 minutes, while radiation-treatment times ranged 7.8-10.4 minutes. Exposure to personnel showed a negligible dose compared to background based on the in-vivo measurements. Our measurements have shown that placement of a shielding layer (FlexiShield) on top of the drape-protected breast reduced radiation exposure to in-room personnel. In one case, treatment was automatically stopped by the controller due to a sudden undetected cooling water flow; due to the pre-treatment training, treatment was successfully resumed within a minute after manual adjustment of the flow sensor.

CONCLUSIONS

Implementation of IORT to treat patients with APBI using low-energy x-ray source should follow the manufacturer's recommendations regarding to the acceptance and personnel training. Our experience indicates that two physicists are necessary at least at the implementation stage. Appropriate training to deal with potential problems is crucial before clinical treatment can be ready.