Disease resistance in rice and the role of molecular breeding in protecting rice crops against diseases

Rice diseases (bacterial, fungal, or viral) threaten food productivity. Host resistance is the most efficient, environmentally friendly method to cope with such diverse pathogens. Quantitative resistance conferred by quantitative trait loci (QTLs) is a valuable resource for rice disease resistance improvement. Although QTLs confer partial but durable resistance to many pathogen species in different crop plants, the molecular mechanisms of quantitative disease resistance remain mostly unknown. Quantitative resistance and non-host resistance are types of broad-spectrum resistance, which are mediated by resistance (R) genes. Because R genes activate different resistance pathways, investigating the genetic spectrum of resistance may lead to minimal losses from harmful diseases. Genome studies can reveal interactions between different genes and their pathways and provide insight into gene functions. Protein–protein interaction (proteomics) studies using molecular and bioinformatics tools may further enlighten our understanding of resistance phenomena.

Effects of tire rubber ash and zinc sulfate on crop productivity and cadmium accumulation in five rice cultivars under field conditions

Cadmium (Cd) is among the most widespread and toxic heavy metals becoming a severe threat to humans. A field study was conducted to examine the role of various zinc (Zn) fertilization treatments and cultivars on crop productivity and Zn and Cd concentrations in brown rice and rice straw. The Zn fertilization treatments included an unfertilized control, foliar applied Zn sulfate (ZnSO4) at panicle initiation stage, foliar applied ZnSO4 at milky stage, soil application of rubber ash, and soil-applied ZnSO4, while five rice cultivars were Swat-1, Shadab, Shua-92, Swat-2, and Sada Hayat. All the Zn fertilization treatments resulted in significantly higher number of panicles, number of spikelets per panicles, spikelet fertility, 1,000-grain weight, grain yield, brown rice and rice straw Zn concentrations, and significantly lower Cd concentrations. Soil application of rubber ash remained the best among all Zn fertilization treatments as it resulted in 73% higher grain yield and reduced Cd concentration by 51% as compared with control. Variations were also apparent among cultivars, and Shua-92 and Swat-2 performed better in terms of all studied attributes as compared with other cultivars. Conclusively, cultivar selection and Zn application are effective strategies to improve rice grain yield as well as quality. Rubber ash appeared a viable source of Zn having the ability to increase yield along with reducing Cd accumulation.

Improved functional assessment of osteoarthritic knee joint after chondrogenically induced cell treatment

OBJECTIVES

Our previous studies on osteoarthritis (OA) revealed positive outcome after chondrogenically induced cells treatment. Presently, the functional improvements of these treated OA knee joints were quantified followed by evaluation of the mechanical properties of the engineered cartilages.

METHODS

Baseline electromyogram (EMGs) were conducted at week 0 (pre-OA), on the locomotory muscles of nine un-castrated male sheep (Siamese long tail cross) divided into controls, adipose-derived stem cells (ADSCs) and bone marrow stem cells (BMSCs), before OA inductions. Subsequent recordings were performed at week 7 and week 31 which were post-OA and post-treatments. Afterwards, the compression tests of the regenerated cartilage were performed.

RESULTS

Post-treatment EMG analysis revealed that the control sheep retained significant reductions in amplitudes at the right medial gluteus, vastus lateralis and bicep femoris, whereas BMSCs and ADSCs samples had no further significant reductions (P < 0.05). Grossly and histologically, the treated knee joints demonstrated the presence of regenerated neo cartilages evidenced by the fluorescence of PKH26 tracker. Based on the International Cartilage Repair Society scores (ICRS), they had significantly lower grades than the controls (P < 0.05). The compression moduli of the native cartilages and the engineered cartilages differed significantly at the tibia plateau, patella femoral groove and the patella; whereas at the medial femoral condyle, they had similar moduli of 0.69 MPa and 0.40-0.64 MPa respectively. Their compression strengths at all four regions were within ±10 MPa.

CONCLUSION

The tissue engineered cartilages provided evidence of functional recoveries associated to the structural regenerations, and their mechanical properties were comparable with the native cartilage.

Drug screen in patient cells suggests quinacrine to be repositioned for treatment of acute myeloid leukemia

To find drugs suitable for repositioning for use against leukemia, samples from patients with chronic lymphocytic, acute myeloid and lymphocytic leukemias as well as peripheral blood mononuclear cells (PBMC) were tested in response to 1266 compounds from the LOPAC¹²⁸⁰ library (Sigma). Twenty-five compounds were defined as hits with activity in all leukemia subgroups (<50% cell survival compared with control) at 10 μM drug concentration. Only one of these compounds, quinacrine, showed low activity in normal PBMCs and was therefore selected for further preclinical evaluation. Mining the NCI-60 and the NextBio databases demonstrated leukemia sensitivity and the ability of quinacrine to reverse myeloid leukemia gene expression. Mechanistic exploration was performed using the NextBio bioinformatic software using gene expression analysis of drug exposed acute myeloid leukemia cultures (HL-60) in the database. Analysis of gene enrichment and drug correlations revealed strong connections to ribosomal biogenesis nucleoli and translation initiation. The highest drug–drug correlation was to ellipticine, a known RNA polymerase I inhibitor. These results were validated by additional gene expression analysis performed in-house. Quinacrine induced early inhibition of protein synthesis supporting these predictions. The results suggest that quinacrine have repositioning potential for treatment of acute myeloid leukemia by targeting of ribosomal biogenesis.

Potential role of phytohormones and plant growth-promoting rhizobacteria in abiotic stresses: consequences for changing environment

Plants are sessile beings, so the need of mechanisms to flee from unfavorable circumstances has provided the development of unique and sophisticated responses to environmental stresses. Depending on the degree of plasticity, many morphological, cellular, anatomical, and physiological changes occur in plants in response to abiotic stress. Phytohormones are small molecules that play critical roles in regulating plant growth and development, as well as stress tolerance to promote survival and acclimatize to varying environments. To congregate the challenges of salinity, temperature extremes, and osmotic stress, plants use their genetic mechanism and different adaptive and biological approaches for survival and high production. In the present attempt, we review the potential role of different phytohormones and plant growth-promoting rhizobacteria in abiotic stresses and summarize the research progress in plant responses to abiotic stresses at physiological and molecular levels. We emphasized the regulatory circuits of abscisic acid, indole acetic acid, cytokinins, gibberellic acid, salicylic acid, brassinosteroids, jasmonates, ethylene, and triazole on exposure to abiotic stresses. Current progress is exemplified by the identification and validation of several significant genes that enhanced crop tolerance to stress in the field. These findings will make the modification of hormone biosynthetic pathways for the transgenic plant generation with augmented abiotic stress tolerance and boosting crop productivity in the coming decades possible.

Potential role of phytohormones and plant growth-promoting rhizobacteria in abiotic stresses: consequences for changing environment

Plants are sessile beings, so the need of mechanisms to flee from unfavorable circumstances has provided the development of unique and sophisticated responses to environmental stresses. Depending on the degree of plasticity, many morphological, cellular, anatomical, and physiological changes occur in plants in response to abiotic stress. Phytohormones are small molecules that play critical roles in regulating plant growth and development, as well as stress tolerance to promote survival and acclimatize to varying environments. To congregate the challenges of salinity, temperature extremes, and osmotic stress, plants use their genetic mechanism and different adaptive and biological approaches for survival and high production. In the present attempt, we review the potential role of different phytohormones and plant growth-promoting rhizobacteria in abiotic stresses and summarize the research progress in plant responses to abiotic stresses at physiological and molecular levels. We emphasized the regulatory circuits of abscisic acid, indole acetic acid, cytokinins, gibberellic acid, salicylic acid, brassinosteroids, jasmonates, ethylene, and triazole on exposure to abiotic stresses. Current progress is exemplified by the identification and validation of several significant genes that enhanced crop tolerance to stress in the field. These findings will make the modification of hormone biosynthetic pathways for the transgenic plant generation with augmented abiotic stress tolerance and boosting crop productivity in the coming decades possible.

Surgical simulation flexor tendon repair using Thiel cadavers: a comparison with formalin embalmed cadavers and porcine models

The aim of this study was to compare Thiel-embalmed cadavers with formalin-embalmed cadavers and porcine models in the surgical simulation repair of a Zone II flexor tendon division. Nine participants were recruited to the study. The models were assessed using a five-point scale. Assessment was divided into tissue quality, surgical approach and identification of structures. Thiel cadavers rated consistently higher compared with the formalin and porcine models (mean 37 SD 2, 22 SD 6 and 23 SD 5, respectively). Thiel cadavers recorded an average tendon glide of 21 mm SD 5, formalin cadavers 2 mm SD 2 and the porcine model 6 mm SD 2. We have demonstrated the benefit of Thiel embalming, with flexibility of tissues allowing testing of the repair of a flexor tendon in a realistic anatomical model.

LEVEL OF EVIDENCE

Level V.

Recent developments in therapeutic protein expression technologies in plants

Infectious diseases and cancers are some of the commonest causes of deaths throughout the world. The previous two decades have witnessed a combined endeavor across various biological sciences to address this issue in novel ways. The advent of recombinant DNA technologies has provided the tools for producing recombinant proteins that can be used as therapeutic agents. A number of expression systems have been developed for the production of pharmaceutical products. Recently, advances have been made using plants as bioreactors to produce therapeutic proteins directed against infectious diseases and cancers. This review highlights the recent progress in therapeutic protein expression in plants (stable and transient), the factors affecting heterologous protein expression, vector systems and recent developments in existing technologies and steps towards the industrial production of plant-made vaccines, antibodies, and biopharmaceuticals.

Clostridium difficile infection in liver transplant recipients: a retrospective study of rates, risk factors and outcomes

Clostridium difficile infection (CDI) occurs in 3-7% of liver transplant recipients (LTR). However, few data exist on the recent epidemiology, predictors and outcomes of CDI in LTR. A cohort study was performed including LTR from 2000 to 2010 at a tertiary care hospital in Detroit. CDI was defined as diarrhea with a stool C. difficile positive test. Data analyzed included demographics, comorbidities, length of stay (LOS), severity of CDI, rates of recurrence (<12 weeks), relapse (<4 weeks) and overall mortality. Predictors of CDI were calculated using Cox proportional hazard model; 970 LTR were followed for years. Overall prevalence of CDI was 18.9%. Incidence of CDI within 1 year of transplant was 12.4%. Severe CDI occurred in 29.1%. CDI recurrence and relapse rates were 16.9% and 9.7%, respectively. Independent predictors of CDI were year of transplant (hazard ratio [HR] 1.137, 95% confidence interval [CI] 1.06-1.22; p < 0.001), white race (105/162 whites, HR 1.47, 95% CI 1.03-2.1; p = 0.035), Model for End-Stage Liver Disease score (HR 1.03, 95% CI 1.01-1.045, p = 0.003) and LOS (HR 1.01, 95% CI 1.005-1.02, p < 0.001). Significant mortality was observed among LTR with CDI compared to those without CDI (p = 0.003). We concluded that CDI is common among LTR and is associated with higher mortality.

Diagnostic accuracy of intraoperative consultation of ovarian neoplasms

Introduction: Ovarian neoplasm’s are an important cause of morbidity and mortality in women. Frozen section is widely used in the intra-operative assessment of patients with ovarian tumors to provide guidance for an appropriate surgical management. It is crucial to know intra-operatively, the exact nature of the tumor to determine the extent of surgery. It is in these situations where the Intraoperative frozen section technique plays its role in making this distinction. Methodology: Females of all ages undergoing planned surgeries for ovarian tumors at Aga Khan Hospital or outside referrals with request for intra operative diagnosis was included. Age of the patient, duration of the lesion and clinical impression were recorded and frozen section was performed. Results: Thirty four cases of ovarian tumors received for frozen section were included in this study. The calculated sensitivity was94.4%, specificity was 93.8%, positive predictive value was 94.4% and negative predictive value was 93.8%. Conclusion: This study shows that frozen section is a highly sensitive and specific method for the rapid diagnosis of ovarian tumors. DOI: http://dx.doi.org/10.3126/ajms.v6i1.10798 Asian Journal of Medical Sciences Vol.6(1) 2015 77-80

Integra™ in burns reconstruction: Our experience and report of an unusual immunological reaction

Limited availability of autologous donor sites poses significant challenges for soft-tissue reconstruction in severe and complex burns. Integra™ is a bi-layered dermal regeneration template (DRT) which has played a significant role in soft tissue reconstruction since its initial use for full-thickness burn defects. The purpose of this study is to report our institutional experience of Integra™ in burns management over a 4-year period and highlight an unusual reaction to its second application. Twenty-four cases underwent Integra™ resurfacing for burn management from September 2007 to August 2011. Data on patient demographics, including co-morbidities, indications, operative data, complications, secondary reconstruction and outcomes were recorded. Integra™ was used in 24 patients on 37 anatomical sites. One patient died 3 weeks after injury and first stage of Integra™ application, and was therefore excluded from the study. Split-thickness skin grafting was performed within an average of 23 days (with a range of 7-55 days) and mean graft take was 87% (with a range of 75-100%). Five cases of local infection at the graft site were recorded. The average length of hospital stay was 47 days (with a range of 1-162 days). The mean follow-up time was 17 months (with a range of 9-34 months). Overall, our experience with DRT was mixed, that is to say we found it satisfactory with acute burns resurfacing but very good with secondary reconstruction. The main advantage of Integra™ is its immediate availability in unlimited quantities for soft-tissue reconstruction in major and complex burns. The main drawbacks are financial implications, twostage procedure, complex wound care and risk of infection. We believe that Integra™ can be considered as a promising modality in burns management.

Currently recommended BK virus (BKV) plasma viral load cutoff of ≥4 log10/mL underestimates the diagnosis of BKV-associated nephropathy: a single transplant center experience

BACKGROUND

BK virus (BKV)-associated nephropathy (BKVAN) is a major cause of renal dysfunction and graft loss in renal transplant recipients. Monitoring plasma BK viral load (BKVL) is the recommended screening tool to predict BKVAN. American Society of Transplantation (AST) guidelines define a BKVL of ≥4 log10/mL (10,000 copies) as presumptive BKVAN and recommend reduction in immunosuppression. We evaluated the clinical sensitivity of the quantitative BKV DNA assay in predicting risk for BKVAN using the AST-recommended BKVL cutoff.

METHODS

In a retrospective, single-center study, all patients who underwent renal transplant at Henry Ford Hospital from January 2008 to August 2011 were analyzed (n = 490). Plasma BKVL Assay A (commercial large T antigen-based polymerase chain reaction [PCR]) was done in all patients. Renal biopsy was done if there was a rise in serum creatinine ≥0.5 mg from baseline. BKVAN was confirmed by biopsy. As a subset to this study, from the same cohort, data for a set of 20 consecutive Assays A and B (in-house VP1-based PCR assay) from 15 patients over a period of 3 months were collected. Differences in physicians' clinical decision-making (CDM) were analyzed between the 2 assays using chi-square test.

RESULTS

A total of 413 patients met the inclusion criteria, of which 222 patients had BK viremia. Among the 248 patients who had a renal biopsy done, 31 (12.5%) were found to have BKVAN. Eleven of the 31 (35%) patients had BKVL consistently <4 log10/mL, and thus were not diagnosed to have BKVAN using the AST-recommended BKVL cutoff of ≥4 log10/mL. A total of 8 patients lost their graft owing to BKVAN, including 3 patients with BKVL <4 log10/mL. Using a cutoff point of plasma BKVL of ≥4 log10/mL, the sensitivity, specificity, positive predictive value, and negative predicative value of the PCR Assay A for the diagnosis of biopsy-proven BKVAN were 64.5%, 98.4%, 87.0%, and 94.5%, respectively, and for the diagnosis of presumptive nephropathy were found to be 76.6%, 99.4%, 95.8%, and 96.4%, respectively. In the second part of the study, presumptive nephropathy was detected in 8 samples using Assay A and 14 samples using Assay B. Six samples in Assay A would have led to no changes in the CDM in terms of reduction in immunosuppression. Kidney biopsy was carried out in 5 patients, 4 of whom had BKVAN and had Assay B log count of ≥5. If Assay A had been used in CDM, BKVAN would have been missed in 1 patient.

CONCLUSION

Utilizing the current AST guideline cutoff of ≥4 log10 /mL, the PCR Assay A underestimated the diagnosis of BKVAN. Urgent standardization of the various BKVL assays and establishment of universal cutoff points is imperative to avoid BKVAN-related graft loss.

Cost-effectiveness of systemic therapies for metastatic pancreatic cancer

PURPOSE

Gemcitabine and capecitabine (gem-cap), gemcitabine and erlotinib (gem-e), and folfirinox (5-fluorouracil-leucovorin-irinotecan-oxaliplatin) are new treatment options for metastatic pancreatic cancer, but they are also more expensive and potentially more toxic than gemcitabine alone (gem). We conducted a cost-effectiveness analysis of these treatment options compared with gem.

METHODS

A Markov model was constructed to examine costs and outcomes of gem-cap, gem-e, folfirinox, and gem in patients with metastatic pancreatic cancer from the perspective of a government health care plan. Ontario health economic and costing data (2010 Canadian dollars) were used. Efficacy data for the treatments were obtained from the published literature. Resource utilization data were derived from a chart review of consecutive metastatic patients treated for pancreatic cancer at Princess Margaret Hospital, Toronto, Ontario, 2008-2009, and supplemented with data from the literature. Utilities were obtained by surveying medical oncologists across Canada using the EQ-5D. Incremental cost-effectiveness ratios (icers) were calculated.

RESULTS

The icers for gem-cap, gem-e, and folfirinox compared with gem were, respectively, CA$84,299, CA$153,631, and CA$133,184 per quality-adjusted life year (qaly). The model was driven mostly by drug acquisition costs. Given a willingness-to-pay (wtp) threshold greater than CA$130,000/qaly, folfirinox was most cost-effective treatment. When the wtp threshold was less than CA$80,000/qaly, gem alone was most cost-effective. The gem-e option was dominated by the other treatments.

CONCLUSIONS

The most cost-effective treatment for metastatic pancreatic cancer depends on the societal wtp threshold. If the societal wtp threshold were to be relatively high or if drug costs were to be substantially reduced, folfirinox might be cost-effective.