Multiparametric MRI-based radiomics nomogram for predicting malignant transformation of sinonasal inverted papilloma

AIM

To investigate the feasibility of a radiomics nomogram model for predicting malignant transformation in sinonasal inverted papilloma (IP) based on radiomic signature and clinical risk factors.

MATERIALS AND METHODS

This single institutional retrospective review included a total of 143 patients with IP and 75 patients with IP with malignant transformation to squamous cell carcinoma (IP-SCC). All patients underwent surgical pathology and had preoperative magnetic resonance imaging (MRI) and computed tomography (CT) sinus studies between June 2014 and February 2022. Radiomics features were extracted from contrast-enhanced T1-weighted images (CE-T1WI), T2-weighted images (T2WI), and apparent diffusion coefficient (ADC) maps. The least absolute shrinkage and selection operator (LASSO) were performed to select the features extracted from the sequences mentioned above. Independent clinical risk factors were identified by multivariate logistic regression analysis. Radiomics nomogram was constructed by incorporating independent clinical risk factors and radiomics signature. Based on discrimination and calibration, the diagnostic performance of the nomogram was evaluated.

RESULTS

Twelve radiomics features were selected to develop the radiomics model with an area under the curve (AUC) of 0.987 and 0.989, respectively. Epistaxis (p=0.011), T2 equal signal (p=0.003), extranasal invasion (p<0.001), and loss of convoluted cerebriform pattern (p=0.002) were identified as independent clinical predictors. The radiomics nomogram model showed excellent calibration and discrimination (AUC: 0.993, 95% confidence interval [CI]: 0.985-1.00 and 0.990, 95% CI: 0.974-1.00) in the training and validation sets, respectively.

CONCLUSION

The nomogram that the combined radiomics signature and clinical risk factors showed a satisfactory ability to predict IP-SCC.

[CT features of abnormally whole-course wide eustachian tubes with microtia and atresia]

Objective: To study the clinical and CT features of the abnormal whole-course wide of eustachian tube (AWWET) with microtia and atresia(MA). Methods: The clinical and CT data of 19 patients (20 ears) from January 2017 to December 2021 with AWWET with MA were retrospectively analyzed, including 15 males and 4 females. The age ranged from 5 to 16 years, with an average of 9.5 years. 50 patients with common MA without wide eustachian tube(ET) as a case control group, including 32 males and 18 females.The age ranged from 5 to 16 years, with an average of 9.2 years. 20 patients (40 ears) who had normal ear CT for tinnitus, otalgia as a normal control group, including 12 males and 8 females. The age ranged from 5 to 16 years, with an average of 12.5 years. We measured the dimension and length of the bony portion of the ET, the total length, the angle between the bony portion and the cartilage portion, and the horizontal angle of ET on CT imagings, and compared with 40 normal ears by SPSS 27.0 software. Results: According to the relationship between AWWET and tympanum, patients were divided into the communicated group and the blocked group. A male predominance, left ear predominance, with high incidence of hemifacial microsomia exhibited in both groups. AWWET was presented as a widened lumen on CT. In 11 ears (4 ears in the communicated group, 7 ears in the blocked group), ETs bifurcated, the upper bony tube extended to the sphenoid body, the lower part continued down to cartilaginous ET and opened onto the nasopharynx, with"mastoid-like"pneumatization of the sphenoid body in 6 ears. The middle ear deformity in case group was more serious than MA control group, especially the blocked group. The incidence of otitis media in the communicated group was lower than that in the MA control group, and 4 cases in the blocked group had effusion in the ET. Compaired with normal ear, the bony ET elongated significantly in the AWWET groups, and the whole course of ET was significantly shortened, specially in the blocked group. The angle between the bony ET and the cartilaginous ET was decreased and the horizontal angle of the ET increased in the AWWET groups, the difference was considered to indicate statistical significance(P<0.05). Conclusions: AWWET with MA is rare, a male predominance, left ear predominance, and with high incidence of hemifacial microsomia. The middle ear deformity is more serious than common MA, especially in the blocked group. The incidence of otitis media in the communicated group is significantly lower than that in the common MA, and the blocked group may be accompanied by ET inflammation.

Separation and purification of active ingredients in tobacco by free-flow electrophoresis

The active ingredients from tobacco extracts were continuously separated and purified using a homemade free-flow electrophoresis apparatus. A rectangular free flow electrophoresis device was constructed for the continuous separation and preparation, and the operating conditions of the device were optimized. The fractions obtained from the free-flowing component collection unit were then detected by HPLC and GC-MS. The results showed that a 90% methanol-water solution could maximize the extraction of the active components from tobacco. Chlorogenic acid and nicotine were enriched in three and four of 24 fractions, respectively, after free-flow isoelectric focusing electrophoresis. 2-Hydroxy-2-cyclopentene-1-one, 1-(2-methyl-1,3-oxathiolan-2-yl) ethanone, nornicotine, cotinine, and scopolamine were separated and enriched synchronously. Overall, the use of free-flow electrophoresis technology for the separation and purification of the active substances in tobacco can improve the comprehensive utilization rate of tobacco.

[The study of relationship between occupational stress and sleep quality of video display terminals]

Objective: To investigate the sleep quality of video operators in Shenzhen, and explore the relationship between sleep quality and occupational stress and different work and life habits. Methods: In December 2020, a cluster sampling method was used to investigate 791 video operators in Shenzhen from June to December 2020 who were engaged in printing, design, IT and other industries. The Pittsburgh Sleep Quality Index Scale was used to investigate the sleep quality of video operators, and the Job Content Questionnaire was used to investigate the occupational stress of video operators, The Pay Return Imbalance Questionnaire was used to investigate the pay return imbalance of video operators. The measurement data conforming to the normal distribution shall be expressed by mean±standard deviation, and t-test, analysis of variance and linear correlation analysis shall be adopted according to the type of independent variable. Those that do not conform to the normal distribution are described by the median M (Q(1), Q(3)), and two sample Wilcoxon test is used according to the binary data of independent variable type. Kruskal Wallis test was used for multi classification data, and Spearman rank correlation was used for single factor analysis for ordinal classification data. The counting data were analyzed by chi square test or Fisher exact probability method. Logistic regression was used for multivariate analysis. Results: the pittsburgh sleep quality index was 4.76±2.86. 499 of them had high sleep quality. 292 people had low sleep quality, accounting for 36.91% (292/791). Compared with the low sleep quality group, the high sleep quality group had lower work requirement scores (13.48±1.77), higher autonomy scores (24.08±3.33), higher social support scores (23.95±3.08), lower pay scores (16.11±2.63), higher return scores (31.11±3.65), and lower internal input scores (14.98±2.55). There were statistically significant differences between the two scales in each dimension index group (P<0.05). Multi factor unconditional logistic regression analysis showed that high education level (OR=1.57, 95%CI=1.26~1.98, P<0.05), occupational stress (OR=1.69, 95%CI=1.21~2.36, P<0.05), and high pay and low return (OR=1.41, 95%CI=1.01~1.96, P<0.05) were the main influencing factors of sleep quality. Conclusion: The occurrence of occupational stress in video operators is a risk factor for low sleep quality, which should be paid enough attention.

A simple and rapid approach for on-site analysis of nicotine in tobacco based on a screen-printed electrode as an electrochemical sensor

In this study, we report a portable kit consisting of a portable workstation, gold screen-printed electrode (SPE), 0.45 μm filter membrane, phosphate buffer solution (PBS), and acetic acid (1%) for point-of-use (POU) analysis of nicotine in tobacco. The activated-screen-printed electrode (A-SPE) displayed superior electron transmission efficiency, and the A-SPE without modification was employed for high-performance analysis of nicotine in actual tobacco after simple sample pretreatment. Remarkably, the fabricated nicotine sensor exhibited a broad working range of 10-100 μg g-1, a low limit of detection (LOD) of 6.4 μg mL-1, good stability, selectivity, and practicality under the optimal conditions. The method was applied to the determination of nicotine in (spiked) samples. Satisfactory recovery results demonstrated that the as-prepared portable kit method with outstanding electrocatalysis ability was feasible for analysis of nicotine in tobacco. Moreover, the values obtained using the A-SPE were in good agreement with those determined by gas chromatography-flame ionization detection (GC-FID), which confirms the feasibility and validity of the present method. The results of the as-proposed portable kit provided a new strategy for analyzing nicotine in actual tobacco samples.

Differentiation of malignant from benign orbital tumours using dual-energy CT

AIM

To investigate the diagnostic accuracy of dual-energy computed tomography (DECT)-derived iodine concentration (IC), effective atomic number (Z_eff), and spectral attenuation information for differentiating malignant and benign orbital tumours.

MATERIALS AND METHODS

Data from 41 patients with orbital tumours from November 2019 to March 2021 were analysed retrospectively. Each patient underwent contrast-enhanced DECT using a 128-section dual-source computed tomography (DSCT) system. Dual-energy information, including IC, normalised iodine concentration (NIC), Z_eff, virtual monoenergetic images (VMIs) reconstructed from 40 to 120 keV and slope (k) value were determined. Quantitative measurement of DECT parameters was undertaken by two independent radiologists blinded to clinical data. Differences in parameters were assessed using independent sample t-test. Diagnosis performance was calculated by the receiver operating characteristic (ROC) curve analysis. Radiation doses of conventional CT and DECT were compared by paired t-tests.

RESULTS

Forty-one patients with histopathologically confirmed tumours were enrolled, including 10 malignant cases and 21 benign cases. Malignant orbital tumours exhibited significantly greater IC, NIC, Z_eff, CT attenuation of VMIs at 40-105 keV, and k values compared to benign orbital tumours (p<0.05). In ROC analyses, 40 keV VMI demonstrated the highest diagnostic performance of single parameters (area under the ROC curve [AUC], 0.940), and combined parameters achieved the best performance (AUC, 0.971; sensitivity, 90%; specificity, 93.55%). Radiation doses were significantly reduced in DECT than conventional CT (p<0.001).

CONCLUSIONS

Quantitative DECT analysis can be a useful technique, which yields excellent diagnostic accuracy, in the differentiation of malignant and benign orbital tumours with low radiation dose.

CT and MRI features of extraocular muscle granular cell tumour: preliminary experience in eight cases

AIM

To characterise the computed tomography (CT) and magnetic resonance imaging (MRI) features, in particular the functional MRI characteristics, of extraocular muscle granular cell tumours (GCTs).

MATERIALS AND METHODS

The CT (n=6) and MRI (n=8) features of eight extraocular muscle GCTs cofirmed at histopathology were analysed retrospectively. The imaging findings were evaluated with emphasis on the location, size, margin, shape, extent, bony change, internal architecture, enhancement pattern, and extent of lesions. Based on diffusion-weighted imaging (DWI) and dynamic contrast-enhanced (DCE) MRI, the apparent diffusion coefficient (ADC) value of six lesions and time-intensity curve (TIC) of one lesion were reviewed.

RESULTS

Immunohistochemistry revealed strong positivity for S-100 protein and a low Ki-67 index (2-5%) in all cases. Most of the lesions (7/8) were confined to the muscle belly with an ovoid shape. All of the tumours were isodense to cerebral grey matter and showed homogeneously mild enhancement on CT images. All lesions were hypointense to cerebral grey matter on T2-weighted imaging (T2WI) and showed homogeneously marked enhancement on contrast-enhanced T1-weighted imaging (T1WI). All lesions showed a hypo- or isointense signal on DWI images with a high b-value. The mean ADC of six lesions was (0.72 ± 0.14) × 10^-3 mm²/s. The TIC of the case examined using DCE-MRI showed a plateau pattern (type II).

CONCLUSION

A well-defined oval mass confined to the muscle belly with a hypointense signal on T2WI, homogeneously marked enhancement on contrast-enhanced T1WI, hypo- or isointense signal on DWI, and low ADC value is highly suggestive of a GCT.

[Clinical and imaging features of middle ear hairy polyps]

Objective: To collect the clinical cases of middle ear hairy polyp, and to summarize the imaging features. Methods: We retrospectively analyzed the clinical data of four cases middle ear hairy polyp confirmed by surgical and pathologic between January 2007 and January 2020 at the Affiliated Eye & ENT Hospital of Fudan University. There were three females, one male, with two left ears and two right ears, aged from 1 to 59 years. The CT and MRI imaging of the patients, and the corresponding clinical manifestations were analyzed. Results: Hairy polyps originated from tympanum in one case, originated from Eustachian tube in two cases, exhibiting recurrent otorrhea without evident inducement. The other case, hairy polyps originated from the Eustachian tube pharyngeal orifice and protruded into the nasopharyngeal cavity, with pharynx discomfort and aural fullness, endoscope showed offwhite polypoid mass with a little hair. All the four cases presented polypoid soft tissue masses on CT and MRI imaging, containing soft tissue wall and a large amount of adipose tissue, with soft tissue in the center of the mass which liked the core, and enhanced. MRI showed stratified arrangement of fat and soft tissue in the wall of the mass. Four cases all had surgical treatment, postoperative pathology examination presented that hair follicles, mature sebaceous glands and other skin appendages were found under squamous epithelium. A large amount of adipose tissue, part of muscle tissue, cartilage tissue, and some fibro-collagenous tissue were proliferated in the mass, accompanied by collagen degeneration. Conclusion: The middle ear hairy polyps has imaging characteristics, the polypoid soft tissue mass usually looks smooth and contains a large amount of adipose tissue, with a soft tissue in the center, and can be suggestively diagnosed by CT and MRI.

[Bax inhibitor-1 inhibits calcification of vascular smooth muscle cells in vitro]

OBJECTIVE

To investigate the effect of Bax inhibitor-1(BI-1)on calcification of vascular smooth muscle cells(VSMCs).

METHODS

VSMCs were isolated from the thoracic aorta of SD rats.VSMCs or BI-1-overexpressing VSMCs(transfected with a BI-1-overexpressing plasmid) were cultured in normal medium or calcified medium containing β-glycerophosphate and calcium chloride, and the cell calcification was examined with Alizarin red staining.Enzyme-linked immunosorbent assay was used to determine the intracellular calcium content and alkaline phosphatase activity.The expression levels of Runt-related transcription factor 2 (RUNX2), bone morphogenetic protein 2 (BMP-2) and caspase-3 were detected with Western blotting.

RESULTS

After 14 days of culture in the calcified medium, the VSMCs showed significantly reduced expression of BI-1 protein(P=0.001).BI-1 overexpression in the VSMCs caused a significant reduction of calcium level and alkaline phosphatase activities(P=0.0006) and lowered the expression levels of RUNX2 and BMP-2 (P=0.0001) in the cells.The VSMCs with induced calcification exhibited a significantly increased apoptosis rate, but BI-1 overexpression obviously inhibited VSMC apoptosis in the calcified medium (P=0.0003).

CONCLUSION

BI-1 may attenuate vascular calcification by inhibiting calcium deposition, osteogenic differentiation and apoptosis.

P–371 Clinical value assessment between endometrial receptivity array and immune profiling in patients with implantation failure

Study question

To evaluate whether the pregnancy outcomes could be improved in implantation failure patients by endometrial receptivity array, endometrial immune profiling, or a combination of both.

Summary answer

There was no statistical difference between different endometrial receptivity evaluation and treatment in improving the clinical pregnancy rate.

What is known already

Both endometrial receptivity array and endometrial immune profiling were promised to improve the endometrial receptivity and subsequent clinical pregnancy. However, less is known about the efficiency between each other and whether the combination could further enhance their clinical value.

Study design, size, duration

Between November 2019 and September 2020, 143 women with a history of at least two or more consecutive implantation failure in IVF/ICSI treatment in Chengdu Xinan Gynecology Hospital were included. They were divided into three groups: ‘ERA + Immune Profiling’ (n = 70), ‘Immune Profiling’ (n = 41), and ‘ERA’ (n = 32).

Participants/materials, setting, methods

Inclusion criteria were age ≤ 38, with normal uterus and uterine cavity. All patients were suggested to evaluate endometrial receptivity by ERA test (Igenomix, Valencia, Spain) and endometrial immune profiling based on immunohistochemistry simultaneously, who would be free to choose each or both evaluation approaches. Personal Embryo Transfer and/or personal medical care were adopted according to evaluation results. Clinical pregnancy was confirmed by gestational sacs observed under ultrasonography.

Main results and the role of chance

The overall prevalence of displaced window of implantation (WOI) is 84.3%, and nearly 74.8% (83/111) patients were diagnosed as endometrial immune dysregulation. Clinical Pregnancy rate and embryonic implantation rate decreased in the ‘Immune Test’ groups, but without a statistical difference (P = 0.311, and 0.158, respectively). Multivariable logistic regression analysis showed that different endometrial receptivity evaluation and treatment was not associated the clinical pregnancy rate, suggesting the performance of different endometrial receptivity evaluation and treatment is similar in improving the clinical pregnancy rate. Neither the immune profiling (CD56, P = 0.591; FOXP3, P = 0.195; CD68, P = 0.820; CD163, P = 0.926; CD1a, P = 0.561; CD57, P = 0.221; CD8, P = 0.427; CD138 CE, P = 0.372) nor histologic endometrial dating defined by Noyes criteria (P = 0.374) were associated with ERA phases.

Limitations, reasons for caution

Although the selection of evaluation approaches was based on patients’ willingness, the variances of baseline characteristics and immune profiling existed in different groups. The immunological treatment efficacy based on immune profiling was not evaluated before embryo transfer.

Wider implications of the findings: To our knowledge, this is the first study comparing the pregnancy outcomes after two typical endometrial receptivity evaluation approaches. The findings highlight the unsubstitutability for each assessment, indicating that both asynchronous and pathological WOI contribute to implantation failure.

Trial registration number

X2019004

Nickel-catalyzed reductive 1,3-diene formation from the cross-coupling of vinyl bromides

Facile construction of 1,3-dienes building upon cross-electrophile coupling of two open-chain vinyl halides is disclosed in this work, showing moderate chemoselectivities between the terminal bromoalkenes and internal vinyl bromides. The present method is mild and tolerates a range of functional groups and can be applied to the total synthesis of a tobacco fragrance solanone.

Sinonasal synovial sarcoma: evaluation of the role of radiological and clinicopathological features in diagnosis

AIM

To explore the value of radiological and clinicopathological features in the diagnosis of sinonasal synovial sarcomas (SS).

MATERIALS AND METHODS

Six patients with sinonasal SS were studied retrospectively using computed tomography (CT; n=6) and magnetic resonance imaging (MRI; n=4). The radiological and clinicopathological findings in this series were reviewed.

RESULTS

Three lesions were located, in both the nasal cavity, and the paranasal sinuses; one was located in the nasal cavity and nasopharynx, and the remaining two were located restrictively within the nasal cavity. An aggressive nature (invasion of adjacent structure) was found in four cases. At CT, lesions were found with isodensity with calcification mainly in the peripheral areas. Bony changes were visible in all cases. Five cases showed marked heterogeneous enhancement, and three cases contained necrotic or cystic areas. At MRI, haemorrhage was observed in three cases. All cases demonstrated the "triple sign", and two high-grade SS showed a "cobblestone-like" appearance on T2-weighted imaging (WI). All time-signal intensity curves (TICs) were of the washout type. The mean apparent diffusion coefficient (ADC) values of the two high-grade cases were lower than those of the low-grade or intermediate-grade cases. Histopathologically, all but one was of the monophasic type. During the 8-40 month period of follow-up, recurrence occurred in four cases.

CONCLUSIONS

A sinonasal tumour exhibiting characteristic calcification and bony change, together with haemorrhage, "triple sign" or "cobblestone-like" appearance, should engender a diagnosis of SS.

A facile approach for rapid on-site screening of nicotine in natural tobacco

Nicotine (Nic) exposed to the environment which comes from tobacco products is the main addictive agent and specific classes of hazardous compound that merit concern. In this study, we have established a fast and reliable method to achieve specific detection of Nic in natural nicotiana tabacum within 30 s through a miniaturized platform based on screen printed gold electrode (SPE). A simple electrochemical pretreatment mean was employed on gold surface that led to the exposure of Au (111) facet and a convenient sample pretreatment method was adopted to realize the extraction of Nic in tobacco. The present electrochemical sensor exhibits an ample range of sensing from 10 μg/g to 200 μg/g, which is able to compliance with tobacco industry testing standards of actual samples. Over 60 sampling points from different origins in China or other countries were performed with direct analysis using this method and satisfactory results have been obtained. The proposed approach was demonstrated to be a very promising platform for significantly improving analytical efficiency in laboratories as well as for monitoring the source reduction control of Nic in the environment.

[Effect of hypocaloric versus standard enteral feeding on clinical outcomes in critically ill adults - A meta-analysis of randomized controlled trials with trial sequential analysis]

OBJECTIVES

To compare the effect of hypocaloric versus standard enteral feeding on clinical outcomes in critically ill adults, and to investigate the influence of protein intake upon the outcome effects of hypocaloric feeding.

DESIGN

A meta-analysis of randomized controlled trials (RCTs) and trial sequential analysis (TSA) were carried out.

SETTING

Intensive Care Unit (ICU).

PATIENTS

Or participants Critically ill adults.

INTERVENTIONS

Hypocaloric enteral feeding versus standard enteral feeding.

MAIN VARIABLES OF INTEREST

The primary outcomes were all-cause short-term mortality and the incidence of nosocomial infection.

RESULTS

Eleven RCTs met the inclusion criteria; of these trials, two were judged as having low risk of bias. Compared with standard enteral feeding, hypocaloric enteral feeding had no benefits in terms of reducing short-term mortality, the incidence of nosocomial infection, or long-term mortality, though it had a positive impact upon the incidence of gastrointestinal intolerance. The TSA further confirmed these results. In turn, hypocaloric enteral feeding had no effects upon the incidence of bloodstream infection, pneumonia, hypoglycemia or the duration of mechanical ventilation, ICU stay, or in-hospital stay. The above results remained unchanged in the sub-analysis of trials with a low risk of bias, trials administering a similar dose of protein, or trials administering different doses of protein.

CONCLUSIONS

Compared with standard enteral feeding, hypocaloric enteral feeding was not associated with better clinical outcomes in critically ill adults, except for a lower risk of gastrointestinal intolerance. The difference in protein intake between groups might have no influence on the outcome effects of hypocaloric enteral feeding. High quality randomized controlled trials are needed to confirm this, however.

Comparison of Solid-Phase Microextraction, Supercritical Fluid Extraction, Steam Distillation, and Solvent Extraction Techniques for Analysis of Volatile Consituents in Fructus Amomi

Four sampling techniques, solid-phase microextraction (SPME), supercritical fluid extraction (SFE), steam distillation (SD), and solvent extraction (SE), were compared for the analysis of volatile constituents from a traditional Chinese medicine (TCM) of the dried ripe fruit of Fructus Amomi (Sha Ren). A total of 38 compounds were identified by gas chromatography/mass spectrometry. Different SFE and SPME parameters (modifier content, extraction pressure, and temperature for SFE and fibers, extraction temperature, and time for SPME) were studied. The results by SFE and SPME were compared with those obtained by conventional SD and SE methods. The results showed that SFE and SPME are better sample preparation techniques than SD and SE. Due to SFE's requirement for expensive specialized instrumentation, the simplicity, low cost, and speed of SPME make it a more appropriate technique for extraction of volatile constituents in TCMs.

[Interference research of umbilical cord mesenchymal stem cells on the pulmonary fibrosis in silicosis rats]

Objective: To explore the effect of the umbilical cord mesenchymal stem cells(UC-MSCs) on the pulmonary fibrosis in silicosis rats. Methods: SPF male Sprague Dawley rats were randomly divided into control group, silica model group and UC-MSCs treatment group with 12 rats each group. SiO(2) intra-tracheal injection(0.5 ml of 50 mg/ml/rat) were applied to silica model group and UC-MSCs treatment groups. After that UC-MSCs treatment group received 1 ml UC-MSCs suspension (3×10(6) cells/ml) by tail vein injection on the 29th, 36th, 43th and 50th day after exposure to the first silica suspension. On the 60th and 75th day after exposure to silica suspension, all animals were examed for pulmonary CT. Then the rats were euthanized on 75th day after the first exposure to silica.Lung's histopathological examination of the rats from all the groups were carried out. The content of hydroxyproline in lungs, TGF-β1 and IL-6 in serum were examined. Results: The lung's histopathological examination showed no obvious inflammatory cell and no fibrosis in the lung tissue of the control group, there were a lot of inflammatory cell aggregation and collagen fiber deposition in silica model group, while in the UC-MSCs intervention group and treatment group, there were less inflammatory cells and collagen fiber. The rats from silica model groups had higher HYP, TGF-β1 and IL-6 than the rats from UC-MSCs treatment group and control group. Lung fields of rats in the control group were clear and no obvious high-density shadow. Different-sized granular high-density shadows or reticular fibrous shadows were found diffusely distributed in the lungs of the rats in silica model group. Lung field of rats in UC-MSCs intervention group and treatment group were less high density shadows, and more clear. Conclusion: UC-MSCs can alleviate the pulmonary fibrosis in silica model rats through regulating the secretion of some fibrosis related cytokines.

[A questionnaire survey for gout management in physicians in Beijing]

Objective: To provide helpful continued medical education (CME) for physicians and improve gout treatment, we conducted a questionnaire survey to investigate physicians' knowledge in nine districts of Beijing. Methods: A questionnaire survey including ten gout-related questions was conducted among 298 physicians in Beijing. Demographic data and previous gout CME experience were collected. Chi-square test or Student's t test, univariate analysis and logistic regression analysis were used to evaluate the relevant factors of physicians' knowledge level. Results: A total of 250 valid copies were collected including 127 from community service centers (CSC), 123 from tertiary hospitals. The correct answer rate of gout etiology, pathogenesis and attack symptoms were over 70% in both groups. 45.5% (56/123) CSC doctors and 57.4% (66/115) tertiary doctors answered right drugs to control acute gout attack (P=0.067). Only 42.3% (52/123) in CSC and 53.4% (63/118) in hospitals chose allopurinol as a urate-lowering drug (ULT), while 46.3% (57/123) and 32.2% (38/118) doctors considered colchicine as a ULT drug (P=0.084) respectively. Near half doctors considered that gout patients should take long-term ULT [40.5% (51/126) vs. 57.6%(68/118)respectively, P=0.007]. Univariate analysis showed that CME training could improve gout-related knowledge in CRC doctors. Conclusion: Most CSC doctors generally understand basic knowledge of gout, while confusion of treatment is still significant. CME especially including standard gout treatment should be performed by doctors in tertiary hospitals.

[Clinical features of adult patients with chronic active Epstein-Barr virus infection]

Objective: To investigate the clinical features of adult-onset chronic active Epstein-Barr virus infection (CAEBV). Methods: A total of 21 adult patients with CAEBV who were admitted to the department of General Internal Medicine at Peking Union Medical College Hospital from January 2006 to January 2016 were retrospectively analyzed. Demographic data, disease duration, clinical manifestations, laboratory findings, treatments and prognosis were reviewed. Results: Eighteen females and 3 males were enrolled with a mean age of 39 years. The most common clinical manifestations included fever in 20 patients, splenomegaly in 20 patients, lymphadenopathy in 18 patients, and hepatomegaly in 10 patients, followed by laryngopharyngeal disorders in 6 patients, pleural effusion and peritoneal effusion each in 5 patients, rash in 4 patients, interstitial lung disease in 3 patients, gastrointestinal hemorrhage in 2 patients, and peripheral neuropathy and pulmonary hypertension each in 1 patient. Six patients were complicated with hemophagocytic lymphohis-tioncytosis(HLH) that developed 5-17 (mean: 9) months following CAEBV onset, all of whom experienced hyperpyrexia, pancytopenia, lymphadenopathy, splenomegaly, and liver dysfunction, 3 with hepatomegaly. Nineteen of the 21 patients had received steroid therapy including 10 combined with immunosuppressive agents, 11 with antiviral therapy, and 8 with intravenous immunoglobulin. Thirteen patients died, including 10 of multiple organ failure, (including 6 of HLH) 2 of severe pulmonary infection, and 1 of lymphoma. Six patients remained on follow-up, yet 2 were missing. Conclusions: CAEBV is expected with severe condition and poor prognosis, which is likely to be complicated with HLH. Clinical physicians should pay attention to adult patients with fever, hepatosplenomegaly and lymphadenopathy, which suggests possible CAEBV.

[The spontaneous herniation of temporomandibular joint into external auditory canal: diagnosis of otoscopy, CT and MRI]

OBJECTIVE

To summarize the otoscopy, CT and MRI features of spontaneous herniation of the temporomandibular joint(TMJ) into the external auditory canal(EAC) through the persistence Huschke's foramen(PHF).

METHODS

The otoscopy, CT and MRI images of three cases with the herniation of the TMJ into the EAC through the PHF were analyzed retrospectively.

RESULTS

Otoscopy revealed the masses located in the antero-inferior aspect of the bony EAC, and the mass displayed an alternative of forward and backward motion during opening and closing of the mouth.CT of the temporal bone showed a bony defect and a consecutive soft mass in the antero-inferior wall of the bony EAC. The margin of the bony defects were well-defined in all cases, the bone adjacent to PHF was pressed and partially wrapped around the soft mass as 'holding ball' in two cases, partly peripheral pseudo bony shell of the soft mass were showed in two cases. The soft mass in EAC appeared equal attenuated with the soft tissue of TMJ, and on enhanced CT scans showed no enhancement of the soft mass. On MRI scans, the imaging displayed a bony defect in the antero-inferior wall of the EAC with a soft mass which was formed by the capsule of the TMJ, and the mass showed iso-signal to the capsule of the TMJ on all sequences, and there was no enhancement after contrast administration.

CONCLUSION

The otoscopy, CT and MRI features of the spontaneous herniation of the TMJ into the EAC through the PHF is special, and the above examinations are valuable for diagnosis of the disease.

Tuning the adsorption behaviors of water, methanol, and ethanol in a porous material by varying the flexibility of substituted groups

The adsorption and separation of water, methanol, and ethanol have been studied based on three iso-reticular metal–organic frameworks, in which the pore surface is decorated with propargyl (–CH₂–CCH), allyl (–CH₂–CHCH₂), and propyl (–CH₂–CH₂–CH₃) groups respectively.

A novel fully automated on-line coupled liquid chromatography-gas chromatography technique used for the determination of organochlorine pesticide residues in tobacco and tobacco products

In this study, a novel fully automated on-line coupled liquid chromatography-gas chromatography (LC-GC) technique was reported and applied for the determination of organochlorine pesticide residues (OCPs) in tobacco and tobacco products. Using a switching valve to isolate the capillary pre-column and the analytical column during the solvent evaporation period, the LC solvent can be completely removed and prevented from reaching the GC column and the detector. The established method was used to determinate the OCPs in tobacco samples. By using Florisil SPE column and employing GPC technique, polarity impurities and large molecule impurities were removed. A dynamic range 1-100ng/mL was achieved with detection limits from 1.5 to 3.3μg/kg. The method exhibited good repeatability and recoveries. This technology may provide an alternative way for trace analysis of complex samples.

Protective effect of ischaemic preconditioning in total knee arthroplasty

OBJECTIVE

To investigate the genomic response induced by ischaemic preconditioning (IPC) in muscle biopsies taken from the operative leg of total knee arthroplasty patients.

MATERIALS AND METHODS

The gene expression profile GSE21164 was extracted from Gene Expression Omnibus (GEO) database. Patients undergoing primary knee arthroplasty were randomized to control and treatment (IPC) groups. Muscle biopsies were taken from the quadriceps muscle of the operative knee at the immediate onset of surgery (T0) and at 1 hour into surgery (T1). Limma package of R language was used to identify the differentially expressed genes (DEGs) between control and treatment group. To find out specific genes, DEGs at T0 were compared with DEGs at T1. Scansite was used to find out the binding domain for specific DEGs. Functional enrichment analysis was done by DAVID.

RESULTS

Of the genes queried on the Affymetrix Human Genome U133 Plus 2.0 microarray, we identified 263 (T0) and 266 (T1) DEGs compared to the control group. Down-regulation of DEGs related with regulation neuron apoptosis was observed at T1. The most significant function of DEGs at T0 was related with neurological system process. The most specific DEG was FAM125B at T0 and T1 time points. Its common binding domain was SH3.

CONCLUSIONS

The protective effect of IPC was associated with altered expression of genes involved in neurological system process and regulation of neuron apoptosis. The dynamic expression of FAM125B can be a supervised marker during the surgery. IPC may be of potential benefit in this and other musculoskeletal conditions.

Preparation of phenyl group-functionalized magnetic mesoporous silica microspheres for fast extraction and analysis of acetaldehyde in mainstream cigarette smoke by gas chromatography-mass spectrometry

Acetaldehyde is regarded as a toxic mainstream cigarette smoke constituent, and measurement of acetaldehyde in complex real samples is difficult owing to its high volatility and reactivity. In this work, phenyl group-functionalized magnetic mesoporous microspheres were developed as the solid-phase extraction sorbents for enrichment and analysis of acetaldehyde in mainstream cigarette smoke. The functional magnetic microspheres were first synthesized through a facile one-pot co-condensation approach. The prepared nanomaterials possessed abundant silanol groups in the exterior surface and numerous phenyl groups in the interior pore-walls, as well as a large surface area (273.5m(2)/g), strong superparamagnetism and uniform mesopores (3.3 nm). Acetaldehyde in mainstream cigarette smoke was collected in water and derivatizated with O-2,3,4,5,6-(pentafluorobenzyl)hydroxylamine. The formed acetaldehyde oximes were extracted and enriched by the prepared adsorbents via π-π interactions and subsequently analyzed using GC-MS. Extraction conditions such as amounts of sorbents, eluting solvent, adsorption and desorption time were investigated and optimized to achieve the best efficiency. Method validations including linearity, recovery, repeatability, and limit of detection were also studied. It was found that the suggested methodology provided low detection limit of 0.04 mg/mL, good recovery of 88-92%, intra-day and inter-day RSD values of 4.5% and 10.1%, and linear range of 0.25-4 mg/mL (R(2)=0.999). The results indicated that the proposed method based on phenyl-functionalized magnetic mesoporous microspheres was rapid, efficient and convenient for the enrichment and analysis of acetaldehyde in tobacco.

Analysis of amino acids in tobacco by derivatization and dispersive liquid-liquid microextraction based on solidification of floating organic droplet method

A new one-step derivatization and microextraction technique was developed for determination of amino acids in tobacco samples. In the proposed method, amino acids were derivatized with isobutyl chloroformate (IBCF) in aqueous solution. The derivatives were extracted by dispersive liquid-liquid microextraction based on solidification of floating organic droplet (DLLME-SFO). Parameters affecting the extraction efficiency were investigated in detail. The optimum conditions were as follows: a mixture of 500μL acetone, containing 40μL 2-dodecanol, was rapidly injected by syringe into the 2mL water sample. After centrifugation, the 2-dodecanol droplets were floated at the top of the tube. Then, the tube was cooled in an ice bath. After 5min the solvent had solidified and was then transferred into a conical vial; it melted quickly at room temperature and it was injected into a gas chromatograph for analysis. Under the optimum conditions, the limits of detection were of the order of 0.12-2.82μg/mL. The calibration curves showed good linearity over the investigated concentration range between 0.5 and 200μg/mL with a coefficient of estimation (R(2))>0.9887 for GC-MS (SIM). The proposed method is an alternative approach to the quantification of amino acids in tobacco samples.

Analysis of the volatile components emitted from cut tobacco processing by gas chromatography/mass spectrometry thermal desorption system

A sensitive and reliable method was developed for the determination of volatile components emitted from cut tobacco processing using thermal desorption (TD) followed by gas chromatography-mass spectrometry (GC-MS). In the work, to obtain the optimal sorbent, three commercial sorbents were compared in terms of adsorption efficiency. The carbotrap 349 was found to have the best performance. The desorption conditions were also studied. Validation of the TD-GC-MS method showed good sensibility, linearity and precision. Limits of detection ranges were from 0.20 to 3.6 ng. Calibration curves were obtained by plotting peak area versus concentration and the correlation coefficients relating to linearity were at least 0.9984. The analysis was reproducible, with relative standard deviation (n=8) within 6.5%. The target compound breakthrough examination showed no significant losses when about 1500 ng standards were prepared. In order to evaluate the performance of the analytical method in the volatile constituents of cut tobacco, samples were taken in industrial areas of cut tobacco processing. Recoveries ranged from 85.1% to 110% for all the compounds and good precision had been reached (RSD<13.3). The results proved that TD-GC-MS was a simple, rapid and accurate method for the analysis of volatile compounds emitted from cut tobacco drying step.

Resistance of Spiroplasma citri Lines to the Virus SVTS2 Is Associated with Integration of Viral DNA Sequences into Host Chromosomal and Extrachromosomal DNA

Spiroplasmavirus SVTS2, isolated from Spiroplasma melliferum TS2, produces plaques when inoculated onto lawns of Spiroplasma citri M200H, a derivative of the type strain Maroc R8A2. S. citri strains MR2 and MR3, originally selected as colonies growing within plaques on a lawn of M200H inoculated with SVTS2, were resistant to SVTS2. Genomic DNA fingerprints and electrophoretic protein profiles of M200H, MR2, and MR3 were similar, but three proteins present in M200H were missing or significantly reduced in both resistant lines. None of these three polypeptides reacted with antiserum against S. citri membrane proteins, indicating that they probably are not surface-located virus receptors. Electroporation with SVTS2 DNA produced 1.5 x 10(sup5) transfectants per (mu)g of DNA in M200H but none in MR2 or MR3, suggesting that resistance may result from inhibition of viral replication. The digestion patterns of the extrachromosomal double-stranded (ds) DNA of these lines were similar. Three TaqI fragments of MR2 extrachromosomal DNA that were not present in M200H extrachromosomal DNA hybridized strongly to an SVTS2 probe, and two of these fragments plus an additional one hybridized with the MR3 extrachromosomal DNA, indicating that a fragment of SVTS2 DNA was present in the extrachromosomal ds DNA of MR2 and MR3 but not of M200H. When the restricted genomes of all three lines were probed with SVTS2 DNA, strong hybridization to two EcoRI fragments of chromosomal MR2 and MR3 DNA but not M200H DNA indicated that SVTS2 DNA had integrated into the genomes of MR2 and MR3 but not of M200H. When MR3 extrachromosomal ds DNA containing a 2.1-kb SVTS2 DNA fragment was transfected into M200H, the transformed spiroplasmas were resistant to SVTS2. These results suggest that SVTS2 DNA fragments, possibly integrated into the chromosomal or extrachromosomal DNA of a previously susceptible spiroplasma, may function as viral incompatibility elements, providing resistance to superinfection by SVTS2.

Development of single-drop microextraction and simultaneous derivatization followed by GC-MS for the determination of aliphatic amines in tobacco

In this work, for the first time, headspace (HS) single-drop microextraction and simultaneous derivatization followed by GC-MS was developed to determine the aliphatic amines in tobacco samples. In the HS extraction procedure, the mixture of derivatization reagent and organic solvent was employed as the extraction solvent for HS single-drop microextraction and in situ derivatization of aliphatic amine in the samples. Fast extraction and simultaneous derivatization of the analytes were performed in a single step, and the obtained derivatives in the microdrop extraction solvent were analyzed by GC-MS. The optimized experiment conditions were: sample preparation temperature of 80 degrees C and time of 30 min, HS extraction solvent (the mixture of benzyl alcohol and 2,3,4,5,6-pentafluorobenzaldehyde) volume of 2.0 microL, extraction time of 90 s. With the optimal conditions, the method validations were also studied. The method has good linearity (R(2) more than 0.99), accepted precision (RSD less than 13%), good recovery (98-104%) and low limit of detection (0.11-0.97 microg/g). Finally, the proposed technique was successfully applied to the analyses of aliphatic amines in tobacco samples of seven different brands. It was further demonstrated that the proposed method offered a simple, low-cost and reliable approach to determine aliphatic amines in tobacco samples.

Development of C18-functionalized magnetic silica nanoparticles as sample preparation technique for the determination of ergosterol in cigarettes by microwave-assisted derivatization and gas chromatography/mass spectrometry

Ergosterol is one of the important precursors of tumorigenic polynuclear aromatic hydrocarbons. A large amount of ergosterol is present in mildewy cigarettes, which derives from fungal contaminations. In this paper, a novel approach based on C(18)-functionalized magnetic silica nanoparticles (C(18)-f-MS NPs) coupled with microwave-assisted derivatization and gas chromatography/mass spectrometry (GC/MS) was developed for the rapid enrichment and determination of ergosterol in cigarettes. Due to that, microwave-assisted derivatization requires very short time (several minutes), and the extraction and concentration of ergosterol become the key step in the sample preparation process. In this study, the prepared C(18)-f-MS NPs with its unique properties (high surface area and strong magnetism) provided an efficient way for extraction and concentration of ergosterol in the samples. Additionally, the analyte of ergosterol adsorbed with C(18)-f-MS NPs in cigarettes can be simply and rapidly isolated (only about 2s) through placing a strong magnet on the bottom of container. In this work, different parameters such as added amounts of C(18)-f-MS NPs, extraction temperature, and extraction time were optimized to enhance the extraction efficiency. Method validations (linear range, detection limit, precision, and recovery) were also studied. The results obtained by the optimal conditions showed that the proposed method based on C(18)-f-MS NPs was a simple, high efficient, and had a rapid approach for the enrichment of ergosterol in cigarettes and was successfully applied to the analysis of ergosterol in normal and mildewy cigarettes followed by microwave-assisted derivatization and GC/MS.

Microwave-assisted silylation followed by gas chromatography/mass spectrometry for rapid determination of ergosterol in cigarettes

Ergosterol is one of the important precursors of tumorigenic polynuclear aromatic hydrocarbons. To the best of our knowledge, a large amount of ergosterol is present in moldy cigarettes, which derives from fungal contaminations. Thus, the development of a simple, fast, and efficient method for the analysis of ergosterol is in great demand. In this paper, GC/MS following microwave-assisted silylation (MAS) was developed for the rapid quantitative analysis of ergosterol in cigarettes for the first time. In our work, total ergosterol in cigarettes after NaOH saponification was extracted with hexane, and then was fast derivatized with bis(trimethylsilyl)trifluoroacetamide (BSTFA) under microwave irradiation. Finally, the ergosterol trimethylsilyl derivative was analyzed by GC/MS. Derivatization conditions including microwave reaction solvent, irradiation time, and power were investigated. Method validations (linear range, LOD, precision, and recovery) were also studied. The results showed that the proposed method provided a fast, simple, and sensitive approach for the determination of ergosterol in cigarettes. Finally it was successfully applied to the analysis of ergosterol in normal and mildewy cigarettes.

Triterpenoid prosapogenols and prosapogenins from the husks of Xanthoceras sorbifolia

Two new prosapogenins, 16-O-acetyl-21-O-(4-angeloyl)-alpha-l-rhamnopyranosyl barringtogenol C (1), 28-O-beta-d-glucopyranosyl 16-deoxybarringtogenol C (2), were isolated from the acid hydrolyzate of the crude saponin obtained from the husks of Xanthoceras sorbifolia Bunge, along with six known triterpenoids. These structures were established on the basis of chemical and detailed spectral evidences. Compounds 1 and 2 showed cytotoxic activity against human cell lines (A375-S2, HeLa).

Norisoprenoids from Ulva lactuca

Five norisoprenoids were isolated from the green marine alga Ulva lactuca. Two new compounds were assigned to (3R,5R,6R,7E)3,5,6-trihydroxy-7-megastigmen-9-one (1) and (3S,5R,6S,7E)3,5,6-trihydroxy-7-megastigmen-9-one (2). The structures and absolute configurations of the five compounds were determined by analyses of NMR, MS and circular dichroism (CD).

A new perylenequinone from the fruit bodies of Bulgaria inquinans

A new perylenequinone, 4,9-dihydroxy-1,2,11,12-tetrahydroperylene-3,10-quinone (1), together with three known compounds, have been isolated from the ethanolic extract of the fruit bodies of Bulgaria inquinans, and their structures elucidated on the basis of the spectral data and comparison with the literature.

A new triterpene glycoside from Asterias rollentoni

A new triterpene glycoside, rollentoside A, has been isolated from Asterias rollentoni Bell and identified as 3beta-O-{3-O-methyl-beta-D-xylopyranosyl-(1-->3)-O-beta-D-glucopyranosyl-(1-->4)-O-beta-D-quinopyranosyl-(1-->2)-O-beta-D-xylopyranosyl}-16-beta-acetoxy-23S-acetoxy-holost-7-ene (1), together with a new natural product, rollentoside B (2). The structures of compounds1 and 2 were elucidated by extensive 1D and 2D NMR investigation (1H-1H COSY, TOCSY, HSQC, HMBC, NOESY).

High-performance liquid chromatographic determination of vertilmicin in rat plasma using sensitive fluorometric derivatization

A sensitive and reliable high-performance liquid chromatographic method was developed for the determination of vertilmicin in rat plasma. Derivatization with 9-fluorenylmethyl chloroformate (FMOC-Cl) followed by C(18) reversed-phase chromatography allowed the fluorimetric detection of vertilmicin. Optimal conditions for the derivatization of vertilmicin are described. The limit of quantification was 0.02 mg/L. The pharmacokinetics of vertilmicin was studied in 24 rats following intramuscular injection (i.m.) of different doses (4, 8, 16, 32 mg/kg of body weight). The pharmacokinetic parameter values were estimated by use of 3P97 program. In this study, we assessed the dose proportionality of vertilmicin after single intramuscular injection doses and obtained new information on the pharmacokinetics of the compound.

A novel sulphur glycoside from the seeds of Descurainia sophia (L.)

A new sulphur glycoside, named descurainoside (1), and the known compound sinapic acid (2) have been isolated from the seeds of Descurainia sophia (L.) Webb ex Prantl. The structure of 1 has been identified as (1R,6S,8R,9S,10S)-9,10-dihydroxy-4-[(4-hydroxy-3,5-dimethoxyphenyl)methylene]-8-(hydroxymethyl)-2,7-dioxa-5-thiabicyclo[4.4.0]decan-3-one by means of physico-chemical properties and spectroscopic methods (1D and 2D NMR, HRMS, ESI-MS).

Comparison of solid-phase microextraction, supercritical fluid extraction, steam distillation, and solvent extraction techniques for analysis of volatile consituents in Fructus Amomi

Four sampling techniques, solid-phase microextraction (SPME), supercritical fluid extraction (SFE), steam distillation (SD), and solvent extraction (SE), were compared for the analysis of volatile constituents from a traditional Chinese medicine (TCM) of the dried ripe fruit of Fructus Amomi (Sha Ren). A total of 38 compounds were identified by gas chromatography/mass spectrometry. Different SFE and SPME parameters (modifier content, extraction pressure, and temperature for SFE and fibers, extraction temperature, and time for SPME) were studied. The results by SFE and SPME were compared with those obtained by conventional SD and SE methods. The results showed that SFE and SPME are better sample preparation techniques than SD and SE. Due to SFE's requirement for expensive specialized instrumentation, the simplicity, low cost, and speed of SPME make it a more appropriate technique for extraction of volatile constituents in TCMs.

Solid-phase microextraction–gas chromatography–mass spectrometric analysis of volatile compounds in a compounded Chinese medicinal prescription, Xiao-Cheng-Qi-Tang

In this paper, a headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography-mass spectrometry (GC-MS) was applied for the analysis of volatile compounds in a famous compounded Chinese medicinal prescription, Xiao-Cheng-Qi-Tang. Some parameters affecting the extraction efficiency such as stirring, extraction temperature, fiber exposure time and desorption time were optimized. The best results were obtained using a 100 microm PDMS fiber during headspace extraction at 90 degrees C with stirring at 1000 rpm for 20 min. Twenty-seven compounds were identified in Xiao-Cheng-Qi-Tang including some main compounds such as d-limonene and linalool. Inter- and intra-day relative standard deviations (R.S.Ds.) were less than 15.6%, showing that the method had a good reproducibility. The result might provide some foundation for building the convincing theory on the pharmacological activity of this prescription.

Quality assessment of Flos Chrysanthemi Indici from different growing areas in China by solid-phase microextraction-gas chromatography-mass spectrometry

Flos Chrysanthemi Indici is a common traditional Chinese medicine (TCM). In this paper, headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS) was developed for quality assessment of Flos Chrysanthemi Indici from different growing areas in China. SPME parameters such as extraction fibers, extraction temperature, extraction time and sample mass were investigated to achieve identical results to those obtained by the steam distillation (SD). The selected SPME conditions were as follows: SPME fiber coated with 65-microm PDMS/DVB, extraction temperature of 60 degrees C, extraction time of 30 min and sample mass of 1.0 g. Furthermore, four active compounds (eucalyptol, camphor, borneol and bornyl acetate) presented in the TCM were applied to evaluating the quality of Flos Chrysanthemi Indici from 20 various areas. The quality assessment was successfully performed to compare the similarity value (S) between different sample vector of Flos Chrysanthemi Indici and the standard profile vector (SPV). The results showed that the proposed HS-SPME-GC-MS was an alternative technique for quality assessment of Flos Chrysanthemi Indici samples.

Headspace solid-phase microextraction and capillary gas chromatographic-mass spectrometric determination of rivastigmine in canine plasma samples

A simple, rapid and sensitive method for determination of rivastigmine in plasma samples was developed using headspace solid-phase microextraction (HS-SPME) and gas chromatography with mass spectrometry (GC-MS). The optimum conditions for the SPME procedure were: headspace extraction on a 65-microm polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber; 0.5 ml of plasma modified with 1.0 ml of sodium hydroxide-sodium carbonate solution (0.7 M:0.5M); extraction temperature of 100 degrees C, with stirring at 2000 rpm for 30 min. The calibration curve showed linearity in the range from 0.2 to 80 ng/ml with regression coefficient corresponding to 0.9965 and coefficient of the variation of the points of the calibration curve lower than 10%. The quantification limit for rivastigmine in plasma was 0.2 ng/ml. The method was applied to determination of rivastigmine in canine plasma samples from animals after a single oral administration.

Generation and flanking sequence analysis of a rice T-DNA tagged population

Insertional mutagenesis provides a rapid way to clone a mutated gene. Transfer DNA (T-DNA) of Agrobacterium tumefaciens has been proven to be a successful tool for gene discovery in Arabidopsis and rice ( Oryza sativa L. ssp. japonica). Here, we report the generation of 5,200 independent T-DNA tagged rice lines. The T-DNA insertion pattern in the rice genome was investigated, and an initial database was constructed based on T-DNA flanking sequences amplified from randomly selected T-DNA tagged rice lines using Thermal Asymmetric Interlaced PCR (TAIL-PCR). Of 361 T-DNA flanking sequences, 92 showed long T-DNA integration (T-DNA together with non-T-DNA). Another 55 sequences showed complex integration of T-DNA into the rice genome. Besides direct integration, filler sequences and microhomology (one to several nucleotides of homology) were observed between the T-DNA right border and other portions of the vector pCAMBIA1301 in transgenic rice. Preferential insertion of T-DNA into protein-coding regions of the rice genome was detected. Insertion sites mapped onto rice chromosomes were scattered in the genome. Some phenotypic mutants were observed in the T1 generation of the T-DNA tagged plants. Our mutant population will be useful for studying T-DNA integration patterns and for analyzing gene function in rice.

Beta-turn formation by a six-residue linear peptide in solution

A model peptide AAGDYY-NH2 (B1), which is found to adopt a beta-turn conformation in the TEM-1 beta-lactamase inhibitor protein (BLIP) in the TEM-1/BLIP co-crystal, was synthesized to elucidate the mechanism of its beta-turn formation and stability. Its structural preferences in solution were comprehensively characterized using CD, FT-IR and 1H NMR spectroscopy, respectively. The set of observed diagnostic NOEs, the restrained molecular dynamics simulation, CD and FT-IR spectroscopy confirmed the formation of a beta-turn in solution by the model peptide. The dihedral angles [(phi3, phi3) (phi4, phi4)] of [(-52 degrees, -32 degrees ) (-38 degrees, -44 degrees )] of Gly-Asp fragment in the model peptide are consistent with those of a type III beta-turn. In a conclusion, the conformational preference of the linear hexapeptide B1 in solution was determined, and it would provide a simple template to study the mechanism of beta-turn formation and stability.