Multifaceted roles of silicon in mitigating environmental stresses in plants.

Food security relies on plant productivity and plant's resilience to climate change driven environmental stresses. Plants employ diverse adaptive mechanisms of stress-signalling pathways, antioxidant defense, osmotic adjustment, nutrient homeostasis and phytohormones. Over the last few decades, silicon has emerged as a beneficial element for enhancing plant growth productivity. Silicon ameliorates biotic and abiotic stress conditions by regulating the physiological, biochemical and molecular responses. Si-uptake and transport are facilitated by specialized Si-transporters (Lsi1, Lsi2, Lsi3, and Lsi6) and, the differential root anatomy has been shown to reflect in the varying Si-uptake in monocot and dicot plants. Silicon mediates a number of plant processes including osmotic, ionic stress responses, metabolic processes, stomatal physiology, phytohormones, nutrients and source-sink relationship. Further studies on the transcriptional and post-transcriptional regulation of the Si transporter genes are required for better uptake and transport in spatial mode and under different stress conditions. In this article, we present an account of the availability, uptake, Si transporters and, the role of Silicon to alleviate environmental stress and improve plant productivity.

A case of unprovoked, precarious, patent foramen ovale protuberance.

This is a case of a precarious thrombotic mass straddling a patent foramen ovale which had already embolised to the pulmonary circulation. The diagnosis was initially deceptive and management challenging. LEARNING POINTS: Echocardiography is mandated and can change management in haemodynamically unstable patients with pulmonary emboli.Pulmonary embolism can be life-threatening.The authors propose that urgent cardiac surgery is the safest treatment in the setting of highly mobile, large volume, intra-cardiac thrombus.

Multidetector computed tomography sizing of bioprosthetic valves: guidelines for measurement and implications for valve-in-valve therapies.

AIM: To describe a technique for bioprosthetic multidetector computed tomography (MDCT) sizing and to compare MDCT-derived values against manufacturer-provided sizing. MATERIALS AND METHODS: Fourteen bioprosthetic stented valves commonly used in the aortic valve position were evaluated using a Philips 256 MDCT system. All valves were scanned using a dedicated cardiac CT protocol with a four-channel electrocardiography (ECG) simulator. Measurements were made of major and minor axes and the area and perimeter of the internal stent using varying reconstruction kernels and window settings. Measurements derived from MDCT (MDCT ID) were compared against the stent internal diameter (Stent ID) as provided by the valve manufacturer and the True ID (Stent ID + insertion of leaflets). All data were collected and analysed using SPSS for Mac (version 21). RESULTS: The mean difference between the MDCT ID and Stent ID was 0.6±1.9 mm (r=0.649, p=0.012) and between MDCT ID and True ID 2.1±2 mm (r=0.71, p=0.005). There was no difference in the major (p=0.90), minor (p=0.87), area (p=0.92), or perimeter (p=0.92) measurements when sharp, standard, and detailed stent kernels were used. Similarly, the measurements remained consistent across differing windowing levels. CONCLUSION: Bioprosthetic stented valves may be reliably sized using MDCT in patients requiring valve-in-valve (VIV) interventions where the valve type and size are unknown. In these cases, clinicians should be aware that MDCT has a tendency to overestimate the True ID size.

Impact of preprocedural mitral regurgitation upon mortality after transcatheter aortic valve implantation (TAVI) for severe aortic stenosis.

OBJECTIVE: To identify the effects of preprocedural significant mitral regurgitation (MR) and change in MR severity upon mortality after transcatheter aortic valve implantation (TAVI) using the Edwards SAPIEN system. METHODS: A retrospective analysis of 316 consecutive patients undergoing TAVI for aortic stenosis at a single centre in the UK between March 2008 and January 2013. Patients were stratified into two groups according to severity of MR: ≥grade 3 were classed as significant and ≤grade 2 were non-significant. Change in MR severity was assessed by comparison of baseline and 30-day echocardiograms. RESULTS: 60 patients had significant MR prior to TAVI (19.0%). These patients were of higher perioperative risk (logistic EuroScore 28.7±16.6% vs 20.3±10.7%, p=0.004) and were more dyspnoeic (New York Heart Association class IV 20.0% vs 7.4%, p=0.014). Patients with significant preprocedural MR displayed greater 12-month and cumulative mortality (28.3% vs 20.2%, log-rank p=0.024). Significant MR was independently associated with mortality (HR 4.94 (95% CI 2.07 to 11.8), p<0.001). Of the 60 patients with significant MR only 47.1% had grade 3-4 MR at 30 days (p<0.001). Patients in whom MR improved had lower mortality than those in whom it deteriorated (log-rank p=0.05). CONCLUSIONS: Significant MR is frequently seen in patients undergoing TAVI and is independently associated with increased all-cause mortality. Yet almost half also exhibit significant improvements in MR severity. Those who improve have better outcomes, and future work could focus upon identifying factors independently associated with such an improvement.

Successful surgical repair of acute type A aortic dissection without the use of blood products.

We report successful surgical treatment of type A aortic dissection in a Jehovah's Witness without the use of any blood products. An interposition graft replacement of the ascending aorta was carried out. This was under right axillo-atrial cardiopulmonary bypass with antegrade cerebral perfusion via right a subclavian and left carotid cannula for 24 minutes at 28°C. Body temperature was kept at 32°C throughout. Autologous transfusion was deployed using cell salvage and a preoperative haemodilution technique. The patient was given tranexamic acid, desmopressin, recombinant factor VIIa, folic acid and epoetin alfa. Patients who object to transfusion represent a significant challenge, especially those who are at a high risk of coagulopathy associated with inherent aortic dissection leading to perturbed haemodynamics, cardiopulmonary bypass and hypothermic circulatory arrest. Type A aortic dissection repair is possible in patients refusing the use of blood products with blood salvage techniques and synthetic products that can limit the risk of bleeding. Minimal hypothermia is vital to preserve platelet function and avoid coagulopathy. Thus, a combination of normothermic/minimal hypothermia and antegrade cerebral protection with a blood conservation strategy can be deployed for a successful surgical outcome in aortic dissection without transfusion.

Artocarpus: a review of its traditional uses, phytochemistry and pharmacology.

The genus Artocarpus (Moraceae) comprises about 50 species of evergreen and deciduous trees. Economically, the genus is of appreciable importance as a source of edible fruit, yield fairly good timber and is widely used in folk medicines. The aim of the present review is to present comprehensive information of the chemical constituents, biological and pharmacological research on Artocarpus which will be presented and critically evaluated. The close connection between traditional and modern sources for ethnopharmacological uses of Artocarpus species, especially for treatment against inflammation, malarial fever, diarrhoea, diabetes and tapeworm infection. Artocarpus species are rich in phenolic compounds including flavonoids, stilbenoids, arylbenzofurons and Jacalin, a lectin. The extracts and metabolites of Artocarpus particularly those from leaves, bark, stem and fruit possess several useful bioactive compounds and recently additional data are available on exploitation of these compounds in the various biological activities including antibacterial, antitubercular, antiviral, antifungal, antiplatelet, antiarthritic, tyrosinase inhibitory and cytotoxicity. Several pharmacological studies of the natural products from Artocarpus have conclusively established their mode of action in treatment of various diseases and other health benefits. Jacalin, a lectin present in seeds of this plant has a wide range of activities. Strong interdisciplinary programmes that incorporate conventional and new technologies will be critical for the future development of Artocarpus as a promising source of medicinal products. In the present review, attempts on the important findings have been made on identification; synthesis and bioactivity of metabolites present in Artocarpus which have been highlighted along with the current trends in research on Artocarpus.

Evaluation of antioxidant capacity and phenol content in jackfruit (Artocarpus heterophyllus Lam.) fruit pulp.

The antioxidant capacity of jackfruit (Artocarpus heterophyllus Lam. Fam. Moracae) fruit pulp (JFP) obtained from Western Ghats India was determined by evaluating the scavenging activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing power assays and N, N-dimethyl-p-phenylendiamine (DMPD) radical cation decolorization assay. JFP was analyzed for total phenolic content (TPC) and total flavonoids content (TFC). The ethanol and water are the best solvents for the extracting phenols and flavonoids from the JFP. The antioxidant activities of JFP extracts were correlated with the total phenolic and flavonoids content. The results indicated that the jackfruit pulp is one natural source of antioxidant compounds.

Diagnosis of acute myocardial infarction: CK-MB versus cTn-T in Indian patients.

The comparative diagnostic efficacy of two cardiac markers: CK-MB and cTn-T, has scarcely been investigated in Indian patients of acute myocardial infarction. The present study was conducted for the same objective. The present study comprised of 59 patients. Males were 44 (75%) and females were 15 (25 %). The age of patients ranged from 32-84 years with mean age of 62.8 yrs. The mean age of males and females were 60 and 63 yrs respectively. All patients presented with history of chest pain with a 12 leads ECG proven MI (ST Elevation, discordant T-waves). CK-MB was estimated in peripheral blood samples at 0,24,48 and 72 hours by an autoanalyzer. Following 12 hours of admission bed side Troponin-T test was done employing cTn-T marker kit. Initially (0 hr), in 50% patients CK-MB was elevated. By end of 24 hours all the patients were CKMB positive and peak level was attained at 24 hrs. Then it tended to decline over next 48 hrs. There were no false positive or negative results. The cTn-T test was positive only in 22 % of ECG positive infarctions. However, the cTn-T positive cases were always accompanied by a higher CK-MB levels. A significantly lower cTn-T positive cases in Indian patients can only be attributed to some difference in amino acid sequence of Indian cTn-T and occidental cTn-T. A larger study from other Indian cardiac centers can either substantiate or contradict our results.

Analysis of the limitations of hepatitis B surface antigen expression in soybean cell suspension cultures.

Soybean cell suspension cultures were transformed using Agrobacterium tumefaciens harboring pHBS/pHER constructs to express hepatitis B surface antigen (HBsAg). The transformed colonies were selected and analyzed for the expression of HBsAg by PCR, reverse transcription (RT) PCR, Western blot and ELISA analysis. The maximum expression of 700 ng/g F.W. was noted in pHER transformed cells. The highest expressing colonies were used to initiate the cell suspension cultures and the expression of HBsAg was estimated periodically. The expression levels were reduced drastically in cell suspension cultures compared to the colonies maintained on semi-solid medium. Various parameters were studied to maximize the cell growth and to retain the expression levels. The supplementation of culture medium with a protease inhibitor, leupeptin hemisulfate could restore up to 50% of HBsAg expression in cell suspension cultures. This is the first report to investigate the possible cause and solution to the loss of recombinant protein expression levels in plant cell suspension cultures.

Production of hepatitis B surface antigen in recombinant plant systems: an update.

There is a growing interest to develop oral vaccines for infectious diseases, as it is the most convenient and effective way to attain mucosal immunity. Hepatitis B continues to be a major infectious disease in many developing countries despite the availability of recombinant vaccine. On a global scenario, Hepatitis B Virus infection is probably the single most prevalent cause of persistent viraemia in humans. There are about 350 million chronic carriers of HBV, which is about 5% of the total world population. It is estimated that 75-100 million of them will die of liver cirrhosis and/or hepatocellular carcinoma. Progress in plant genetic engineering has enabled the transfer of useful genes for desirable traits. The recent trend is to use this technique to exploit plants as biofactories for the production of therapeutic proteins including vaccines. Rapid progress has been made in this area to develop plant-based vaccines for hepatitis B. This review describes the expression, characterization, and immunogenicity studies of hepatitis B vaccines produced in recombinant plant systems and their implications for developing a plant-based vaccine.

Secretion of hepatitis B surface antigen in transformed tobacco cell suspension cultures.

Six different expression cassettes of hepatitis B surface antigen (HBsAg) were used to transform tobacco cell suspension cultures. The transgenic nature of the cells was confirmed by PCR. The secreted HBsAg was assayed by ELISA and analyzed by Western blotting. A maximum of 31 microg antigen/l was obtained in the spent medium from the transformed cells. The use of an ethylene-forming enzyme promoter and incorporation of C-terminal endoplasmic-reticulum-retention signal enhanced the secretion of HBsAg. Salicylic or jasmonic acid at 10 microM: increased secretion of HBsAg by six fold.

Expression of hepatitis B surface antigen in transgenic banana plants.

Embryogenic cells of bananan cv. Rasthali (AAB) have been transformed with the 's' gene of hepatitis B surface antigen (HBsAg) using Agrobacterium mediated transformation. Four different expression cassettes (pHBS, pHER, pEFEHBS and pEFEHER) were utilized to optimize the expression of HBsAg in banana. The transgenic nature of the plants and expression of the antigen was confirmed by PCR, Southern hybridization and reverse transcription (RT)-PCR. The expression levels of the antigen in the plants grown under in vitro conditions as well as the green house hardened plants were estimated by ELISA for all the four constructs. Maximum expression level of 38 ng/g F.W. of leaves was noted in plants transformed with pEFEHBS grown under in vitro conditions, whereas pHER transformed plants grown in the green house showed the maximum expression level of 19.92 ng/g F.W. of leaves. Higher monoclonal antibody binding of 67.87% of the antigen was observed when it was expressed with a C-terminal ER retention signal. The buoyant density in CsCl of HBsAg derived from transgenic banana leaves was determined and found to be 1.146 g/ml. HBsAg obtained from transgenic banana plants is similar to human serum derived one in buoyant density properties. The transgenic plants were grown up to maturity in the green house and the expression of HBsAg in the fruits was confirmed by RT-PCR. These transgenic plants were multiplied under in vitro using floral apex cultures. Attempts were also made to enhance the expression of HBsAg in the leaves of transgenic banana plants by wounding and/or treatment with plant growth regulators. This is the first report on the expression of HBsAg in transgenic banana fruits.

Expression of hepatitis B surface antigen in tobacco cell suspension cultures.

Hepatitis B virus ' s ' gene coding for surface antigen was cloned into plant transformation vectors pHER100 and pHBs100 with and without endoplasmic reticulum retention signal, respectively. Transformed tobacco cell lines were analyzed for the integration of the transgene by PCR and Southern blot hybridization. Expression levels as determined by ELISA showed maximum expression levels of 2 microg HBsAg gm(-1) fresh weight and 10 ng mL(-1) of spent medium in pHER100 transformed cells. Western blot analysis confirmed the presence of 24 kDa band specific to HBsAg in the transformed cells. HBsAg was expressed both as intracellular and secreted forms in pHER100 transformed cells. The buoyant density in CsCl of HBsAg derived from pHBs100 transformed tobacco cells was determined and found to be 1.095 g mL(-1). HBsAg obtained from transformed tobacco cells is similar to the human serum derived one in buoyant density properties. This is the first report on the secretion of HBsAg particles by plant cells into the cell culture medium.

Herniation of the heart into the right pleura following blunt chest trauma--an unusual presentation.

A 21-year-old male patient had sustained a blunt chest and abdominal trauma during a traffic accident. All the major injuries were on the left side. On the second day, a massive shift of the mediastinum to the right was noted. Further investigations raised the suspicion of herniation of the heart into the right pleural cavity. However, the patient's hemodynamic stability did not fit into the picture. Echocardiography and CT scan helped reinforce our suspicion. Herniation was confirmed at the operation, which was performed through median sternotomy. The patient recovered well without complications.

MSI-99, a magainin analogue, imparts enhanced disease resistance in transgenic tobacco and banana.

Magainin is one of the earliest reported antimicrobial peptides isolated from skin secretions of the African clawed frog Xenopus laevis. A synthetic substitution analogue of magainin, MSI-99, is employed in this study to impart disease resistance in transgenic tobacco ( Nicotiana tabacumL.) and banana [( Musaspp. cv. Rasthali (AAB)]. This peptide inhibited the growth and spore germination of Fusarium oxysporumf.sp. cubenseat 16 micro g/ml. MSI-99 has been subcloned into plant expression vectors pMSI164 and pMSI168, targeting the peptide into the cytoplasm and extracellular spaces, respectively. Tobacco plants transformed with pMSI168 showed enhanced resistance against Sclerotinia sclerotiorum, Alternaria alternataand Botrytis cinerea. Transgenic banana pants were obtained for both pMSI164 and pMSI168 transformations and showed resistance to F. oxysporumf.sp. cubenseand Mycosphaerella musicola. The transgenic nature of the transformants and expression of this peptide was confirmed through polymerase chain reaction (PCR) and reverse transcription (RT)-PCR. The results suggest that MSI-99 can be useful in imparting enhanced disease resistance in transgenic plants.

Malaria still a threat to life--a postmortem study.

This study is of 25 cases of acute malaria encountered at autopsy. Cause of death was malaria in all the cases. The study covers a period of 6 years i.e. from January 1994 to December 1999. There was an upward trend in deaths due to malaria. P. falciparum malaria with its complications accounted for majority of deaths and cerebral malaria (CM) topped the list. Other complications observed were adult respiratory distress syndrome (ARDS), acute septicemic malaria, acute renal failure (ARF) and disseminated intravascular coagulation (DIC). The commonest presenting symptoms were fever with chills associated with central nervous system (CNS) complaints like altered sensorium and unconsciousness.

Study of trace element correlations with drought tolerance in different sorghum genotypes using energy-dispersive X-ray fluorescence technique.

Drought-tolerant and drought-susceptible genotypes of sorghum (Sorghum bicolor L. Monech) were analyzed by the energy-dispersive X-ray fluorescence (EDXRF) technique to study the correlation of trace elements with drought-tolerance capacities. Samples prepared from mature seeds, young seedlings, and old plants were analyzed using a 109Cd radioisotope source and a Si(Li) semiconductor detector of resolution 170 eV for 5.9-keV MnKalpha X-rays. Elements such as K, Fe, Cu, Zn, Rb and Sr and Y were found to be present in varying concentrations in different samples. The trace element profile studied in the seeds of 11 genotypes and in seedlings (young and old) of 4 sorghum genotypes showed considerable variation. The genotype Arfa Gadamak (AG) showed a distinct presence of a high level of Zn in its young seedling. It was observed that in most of the genotypes (seeds), K and Fe concentrations were more in the tolerant genotype as compared to the susceptible type. The concentration of Fe decreased with maturity in the tolerant group and it increased with maturity in the susceptible group.

Entomopthoromycosis--report of four cases.

Entomopthoromycosis is a rare subcutaneous infection and manifests in two clinically distinct forms. Subcutaneous zygomycosis which manifests as a painless nodule on the trunk or the extremities and rhinofacial zygomycosis which is a locally progressive infection of the nasal cavity, paranasal sinuses and soft tissues of the face. Neither of these two forms occur in patients with underlying disease or defective immunity. Here we report four cases of entomopthoromycosis.