A rapid detection of tomato yellow leaf curl virus using recombinase polymerase amplification-lateral flow dipstick assay

Tomato yellow leaf curl disease which is caused by Tomato yellow leaf curl virus (TYLCV) is economically important and a widely spread tomato disease in China. Rapid and accurate detection methods are important in the control TYLCV. Here, a rapid method was developed to identify TYLCV on the basis of recombinase polymerase amplification (RPA) that can be visualized in 5 min using lateral flow dipsticks. The sensitivity and the specificity of this method were evaluated. This method can detect 0·5 pg DNA after 30 min at 37°C without any expensive instrumentation. In addition, it showed higher sensitivity than a PCR method when purified DNA was used. Moreover, the TYLCV was specifically detected, whereas other viruses infecting tomato produced negative results. The crude tomato extracts used in this assay has potential application in minimally equipped plant clinic laboratories. This method will facilitate the early and rapid detection of TYLCV for the timely application of control measures.

Clinicopathologic factors that influence prognosis and survival outcomes in men with metastatic castration-resistant prostate cancer treated with Radium-223

Background

In men with metastatic castration‐resistant prostate cancer (mCRPC) with primarily bone metastases, radium‐223 (²²³Ra) improves overall survival (OS). However, the selection of ²²³Ra is not guided by specific validated clinicopathologic factors, and thus outcomes are heterogeneous.

Patients and methods

This retrospective survival analysis was performed in men with mCRPC treated with ²²³Ra at our cancer center. Demographics and disease characteristics were collected. OS was calculated using the Kaplan–Meier method (log‐rank). The potential prognostic factors were determined using both univariable (UVA) and multivariable analysis (MVA) (Cox‐regression) methods.

Results

In total, 150 patients with a median age of 74 years (52–93) received ²²³Ra between May 2015 and July 2018, and 58% had 6–20 bone metastases. Ninety‐four (63%) patients received >4 ²²³Ra doses, and 56 (37%) received ≤4. The following pre‐treatment factors were analyzed (median [range]): eastern cooperative oncology group performance status (ECOG PS), (1 [0–3]); Albumin (ALB), (39 g/L [24–47]); alkaline phosphatase (ALP), (110 U/L [35–1633]); and prostate‐specific antigen (PSA), (49 µg/L [0.83–7238]). The median OS for all patients was 14.5 months (95% CI: 11.2–18). These factors were associated with poor survival outcomes in UVA and MVA: ALB <35 g/L, ALP >150 U/L, ECOG PS 2–3, and PSA >80 µg/L. By assigning one point for each of these factors, a prognostic model was developed, wherein three distinct risk groups were identified: good, 0–1 (n = 103); intermediate, 2 (n = 30); and poor risk, 3–4 points (n = 17). The median OS was 19.4, 10.0, and 3.1 months, respectively (p < 0.001).

Conclusions

Pre‐treatment ALB, ALP, ECOG, and PSA, were significantly correlated with OS and could guide treatment selection for men with mCRPC by identifying those who are most or least likely to benefit from ²²³Ra. Validation in an independent dataset is required prior to widespread clinical utilization.

Impact of adjuvant therapy in patients with a microscopically positive margin after resection for gastric and esophageal cancers

Background

A microscopically positive (R1) resection margin following resection for gastric and esophageal cancers has been documented to be a poor prognostic factor. The optimal strategy and impact of different modalities of adjuvant treatment for an R1 resection margin remain unclear.

Methods

A retrospective analysis was performed for patients with gastric and esophageal adenocarcinoma treated at the Princess Margaret Cancer Centre (PMCC) from 2006-2016. Electronic medical records of all patients with an R1 resection margin were reviewed. Kaplan-Meier and Cox proportional hazards methods were used to analyze recurrence free survival (RFS) and overall survival (OS) with stage and neoadjuvant treatment as covariates in the multivariate analysis.

Results

We identified 69 gastric and esophageal adenocarcinoma patients with a R1 resection. Neoadjuvant chemoradiation was used in 13% of patients, neoadjuvant chemotherapy in 12%, surgery alone in 75%. Margins involved included proximal in 30%, distal in 14%, radial in 52% and multiple margins in 3% of patients. Pathological staging showed 3% with stage I disease, 20% stage II and 74% stage III. Adjuvant therapy was given in 52% of R1 pts (28% CRT, 20% chemotherapy alone, 3% radiation alone, 1% reoperation). Median RFS was 14.1 months [95% confidence interval (CI), 11.1-17.2]. The site of first recurrence was 72% distant, 12% mixed, 16% locoregional alone. Median OS was 34.5 months (95% CI, 23.3-57.9) for all patients. There was no significant difference in RFS (adjusted P=0.26) or OS (adjusted P=0.83) comparing modality of adjuvant therapy.

Conclusions

Most patients with positive margins after resection for gastric and esophageal cancer had advanced pathologic stage and prognosis was poor. Our study did not find improved RFS or OS with adjuvant treatment and only one patient had reresection. The main failure pattern was distant recurrence, suggesting that patients being considered for adjuvant radiotherapy (RT) should be carefully selected. Further studies are required to determine factors to select patients with good prognosis despite a positive margin, or those who may benefit from adjuvant treatment.

Surveillance and outcomes after curative resection for gastroesophageal adenocarcinoma

Background

The goal of surveillance testing is to enable curative salvage therapy through early disease detection, however supporting evidence in gastroesophageal adenocarcinoma is limited. We evaluated frequency of successful salvage therapy and outcomes in patients who underwent surveillance.

Methods

A single‐site, retrospective cohort study was conducted to identify all patients who received curative resection for gastroesophageal adenocarcinoma. Surveillance testing were those investigations not triggered by abnormal symptoms, physical examination, or blood tests. Successful salvage therapy was any potentially curative therapy for disease recurrence which resulted in postrecurrence disease‐free survival ≥2 years. Time‐to‐event data were analyzed using the Kaplan‐Meier method and log rank tests.

Results

Between 2011 and 2016, 210 consecutive patients were reviewed. Esophageal (14%), gastroesophageal junction (40%), and gastric adenocarcinomas (45%) were treated with surgery alone (29%) or multimodality therapy (71%). Adjuvant therapy was administered in 35%. At median follow‐up of 38.3 months, 5‐year overall survival (OS) rate was 56%. Among 97 recurrences, 53% were surveillance‐detected, and 46% were symptomatic. None was detected by surveillance endoscopy. Median time‐to‐recurrence (TTR) was 14.8 months. Recurrences included locoregional only (4%), distant (86%), and both (10%). Salvage therapy was attempted in 15 patients, 4 were successful. Compared to symptomatic recurrences, patients with surveillance‐detected recurrences had longer median OS (36.2 vs 23.7 months, P = .004) and postrecurrence survival (PRS, 16.5 vs 4.6 months, P < .001), but similar TTR (16.2 vs 13.3 months, P = .40) and duration of palliative chemotherapy (3.9 vs 3.3 months, P = .64).

Conclusions

Among patients surveyed, 96% of recurrences were distant, and salvage therapy was successful in only 1.9% of patients. Longer OS in patients with surveillance‐detected compared to symptomatic recurrences was not associated with significant earlier disease detection, and may be contributed by differences in disease biology. Further prospective data are warranted to establish the benefit of surveillance testing in gastroesophageal adenocarcinoma.

Application of the ASCO Value Framework and ESMO Magnitude of Clinical Benefit Scale to Assess the Value of Abiraterone and Enzalutamide in Advanced Prostate Cancer

PURPOSE

As novel hormonal therapies, such as abiraterone and enzalutamide, move into earlier stages of treatment of advanced prostate cancer, there are significant cost implications. We used the ASCO Value Framework (AVF) and European Society of Medical Oncology (ESMO) Magnitude of Clinical Benefit Scale (MCBS) to quantify and compare the incremental clinical benefit and costs of these agents in the metastatic castration-resistant prostate cancer (mCRPC) and metastatic castration-sensitive prostate cancer (mCSPC) settings.

METHODS

We searched PubMed for randomized phase III trials of abiraterone and enzalutamide in mCRPC and mCSPC. Incremental clinical benefit was quantified using the AVF and ESMO-MCBS by 2 independent assessors. Incremental drug costs were calculated using average wholesale prices (AWPs) from the RED BOOK Online.

RESULTS

In mCRPC, 2 abiraterone trials (COU-AA-301 and COU-AA-302) and 2 enzalutamide trials (AFFIRM and PREVAIL) met search criteria. AVF scores ranged from 46.3 to 66.6, suggesting clinical benefit; ESMO-MCBS scores ranged from 3 to 5, with lower clinical benefit in the mCRPC predocetaxel setting. The overall incremental AWP ranged from $83,460.94 to $205,128.85. In mCSPC, 4 trials met criteria (LATITUDE, STAMPEDE, ENZAMET, and ARCHES; AVF scores were 79.8, 33.3, 59, and 17, respectively). All of the studies showed benefit except ARCHES. By ESMO-MCBS, both LATITUDE and STAMPEDE showed benefit (score for 4 for both studies); ENZAMET and ARCHES were not evaluable. The overall cost of treatment was significantly higher in the mCSPC setting.

CONCLUSION

The AVF and ESMO-MCBS frameworks generated slightly different results but suggested that abiraterone and enzalutamide show clinical benefit in both mCRPC and mCSPC but trended to lower clinical benefit and increased costs in earlier disease stages. Further refinement of the AVF and ESMO-MCBS is needed to facilitate their use and their ability to inform clinical practice in a rapidly changing treatment landscape.

First Report of Coleus blumei viroid 5 from Coleus blumei in India and Indonesia

Coleus blumei, which was found originally in Indonesia, is an ornamental plant grown worldwide. It can be infected by several viroids of the genus Coleviroid, family Pospiviroidae. Six main viroids that infect coleus have been reported: Coleus blumei viroid 1 through 6 (CbVd-1 ~ CbVd-6). Although CbVd-1 was first reported in a commercial coleus in Brazil in 1989 (1), and then in Germany, Japan, Canada, Korea, China, and India, CbVd-5 was reported only in China in 2009 (2). Symptoms caused by CbVd-5 varied depending on different cultivars, and in case of an unknown cultivar of "Red with dark green edge," are very clear albino symptoms. From 2010 to 2011, 60 and 3 leaf samples of coleus were collected from Hyderabad, India, and Java, Indonesia, respectively, and subjected to low molecular weight RNA extraction according to Li et al. (3). The results of dot-blot hybridization using CbVd-5 cRNA probes and RT-PCR using CbVd-5 specific primers (CbVd-5-P_F: 5'-TGACTAGAACAGTAGTAAAG-3' / CbVd-5-P_R: 5'-AATTGAGGTCAAACCTCTTT-3') demonstrated that 28 out of the 60 samples from India and all three samples from Indonesia were positive for CbVd-5. The resulting RT-PCR fragments from one sample selected randomly from each country were cloned into the pMD18-T vector (Takara) and transformed into E. coli DH5α competent cells. Five positive clones of each sample were sequenced. The result of sequence analysis revealed that the similarities of CbVd-5 between the sequences we obtained and the reference sequence (GenBank Accession No. NC003683) were 97.8 to 100%. Bioassay using nine viroid-free coleus plants from three cultivars (three from each cultivar), inoculated with CbVd-5 infectious clones by stem slashing, demonstrated that CbVd-5 could induce albino symptom on the leaves of the unknown cultivar "Red with dark green edge" 2 months after inoculation. To our knowledge, this is the first report of CbVd-5 from India and Indonesia, and the second report of CbVd-5 in the world. Considering the effect of CbVd-5 on the appearance of coleus and its recombination ability, a certification program may be needed to control the spread of this viroid. References: (1) M. E. N. Fonseca et al. Fitopatol. Bras. 14:94, 1989. (2) W. Y. Hou et al. Arch. Virol. 154:315, 2009. (3) S. F. Li et al. Ann. Phytopathol. Soc. Jpn. 61:381, 1995.

First Report of Coleus blumei viroid 2 from Commercial Coleus in China

Coleus (Coleus blumei) is an ornamental plant that is susceptible to infection by several viroids of the genus Coleviroid, which is a member of the family Pospiviroidae. Coleus blumei viroid (CbVd) -1 was first reported in commercial yellow coleus fields in Brazil in 1989 (1). In addition, CbVd-2, CbVd-3, and CbVd-4 have only been detected from coleus in Germany in 1996 (4). CbVd-5 and CbVd-6 were recently identified in China (2). In March 2010, leaves were collected from 50 symptomless coleus plants from a commercial nursery in Hainan Province, China. Total RNA was extracted from the leaves (3). Reverse transcription (RT)-PCR using CbVd-2 specific primers (forward: 5'-AGCTTACCTGGGTTCCCT-3' and reverse: 5'-CTCTCCTCTATTTACTCTCTTCTC-3') corresponding to positions 76 to 93 and 52 to 75 on the CbVd-2 reference sequence, respectively (GenBank Accession No. NC003682). Amplification of a 301-bp product was obtained from one sample. This PCR product was then cloned into pMD18-T (Takara, Dalian, China). Twelve positive clones were sequenced and the results were subjected to BLAST analysis. Sequence analysis showed that two sequences (GenBank Accessions Nos. HQ727542 and HQ727544) shared 99% identity with the reference sequence of CbVd-2 (NC003682), and four sequences (HQ727541, HQ727543, HQ727545 and HQ727547) had 99.34% identity with the reference sequence of CbVd-2 (NC003682). The proposed secondary structures of these variants have approximately 75% paired nucleotides. Results suggested the presence of CbVd-2, which is a member of the Coleviroid genus, Pospoviroidae family. To our knowledge, this is the first report of CbVd-2 from commercial coleus in China. References: (1) M. E. N. Fonseca et al. Fitopatol. Bras. 14:94, 1989. (2) W. Y. Hou et al. Arch. Virol. 154:993, 2009. (3) S. F. Li et al. Ann. Phytopathol. Soc. Jpn. 61:381, 1995. (4) R. L. Spieker et al. J. Gen. Virol. 77:2839, 1996.

Immunological study of allogeneic mesenchymal stem cells during bone formation

Autologous mesenchymal stem cells (MSCs) are limited in their clinical application because tissue-engineered bone cannot be pre-fabricated. Allogeneic MSCs are readily available but carry the risk of transplant rejection. It is not yet clear whether allogeneic MSCs can induce a rejection response during bone formation. In this study, two strains of genetically unmatched mini-pigs were used as experimental animals to study the immunological changes in MSCs in vitro and in vivo when generating bone. Mini-pig MSCs showed low immunogenicity during osteogenesis both in vitro and in vivo, indicating that allogeneic MSCs had little or no immunogenicity in osteosis. In conclusion, allogeneic MSCs are an important source of seed cells for the tissue engineering of bone. This favours the clinical application of pre-constructed tissue-engineered bone.

Approximation of flammability region for natural gas-air-diluent mixture

The growing implementation of exhaust gas recirculation (EGR) in reducing NO(x) emissions of engine is of paramount motivation to perform a fundamental research on the flammability characteristics of fuel-air-diluent mixtures. In this work, the influences of EGR on the flammability region of natural gas-air-diluent flames were experimentally studied in a constant volume bomb. An assumption of critical burning velocity at flammability limit is proposed to approximately determine the flammability region of these mixtures. Based on this assumption, an estimation of the flammability map for natural gas-air-diluent mixtures was obtained by using the empirical formula of burning velocity data. The flammability regions of natural gas-air mixtures with EGR are plotted versus the EGR rate. From the comparison of estimated results and experimental measurements, it is suggested that the accuracy of prediction is largely dependent upon the formula of burning velocity used. Meanwhile, the influence of pressure on the critical burning velocity at flammability limit is also investigated. On the basis of the pressure dependence criterion, the estimation was performed for the circumstance of high temperature and pressure, and the prediction results still agree well with those of experiments.

Experimental study of flammability limits of natural gas-air mixture

Flammability limits data are essential for a quantitative risk assessment of explosion hazard associated with the use of combustible gas. The present work is to obtain the fundamental flammability data for prevention of the hazards in the practical applications. Experiments have been conducted in a constant volume combustion bomb, and the fuel considered here is natural gas (NG). The pressure histories in the combustion bomb are recorded and a criterion of 7% pressure rise has been used to judge a flammable mixture. The effects of ethane on NG-air flammability limits have been investigated. By adding diluent (carbon dioxide, nitrogen or their mixture) into NG-air mixture, the dilution effects on the flammability limits have been explored as well, and the results are plotted as functions of diluent ratio.

[Comparative study on osteogenesis of three types growth factors recombination artificial bones]

OBJECTIVE

To compare the osteogenesis of recombination artificial bones, which are bovine deproteined bone (bDPB) and bovine bone morphogenetic protein (bBMP), combined with tumor necrosis factor alpha (TNF alpha), basic fibroblast growth factor (bFGF), epidermal growth factor (EGF) respectively.

METHODS

One hundred trephined skull bone defects in fifty rabbits were divided into four groups, which implanted with bDPB/bBMP/TNF alpha, bDPB/bBMP/bFGF, bDPB/bBMP/EGF, and bDPB/bBMP respectively. X-ray and histological changes were observed in the 1st, 2nd, 4th, 6th, 8th weeks after implantation. The content of 35S and 45Ca and ash weight were measured at 10 and 42 days after operation.

RESULTS

The osteogenesis of bDPB/bBMP/TNF alpha group was stronger than that of bDPB/bBMP/bFGF group(P < 0.01), while bDPB/bBMP/bFGF group was stronger than that of bDPB/bBMP/EGF(P < 0.01). No significant statistical difference were found between bDPB/bBMP/EGF and bDPB/bBMP(P > 0.05).

CONCLUSION

TNF alpha combined with bBMP and carrier can stimulate bone formation and increase the volume of new bone in vivo. It suggests that bDPB/bBMP/TNF alpha is a valuable biomaterial of bone graft.

[Mismatch negativity (MMN) to very short interval between regular tones]

The Mismatch Negativity (MMN) component of the auditory event-related potential (AERP) is elicited by infrequent, physically "deviant" stimuli in a sequence of frequent homogeneous stimuli ("standard"), for instance, by a change in frequency, intensity or duration etc. When the inter-stimulus interval (ISI) of tone pips was occasionally shortened either to 300, 150, 75, 60 and 52 ms from regular ISI 600 ms, which resulted in the elicitation of MMN. The amplitude of MMN elicited by occasional shorter ISI was not reduced as a function of ISI shortening. This indicates that the MMN is not just due to activation of new afferent elements by deviant stimulus. Thus, by no means the elicitation of the MMN can be explained on the basis of the refractoriness.