Augmentation of cognitive function by NS9283, a stoichiometry-dependent positive allosteric modulator of α2- and α4-containing nicotinic acetylcholine receptors

BACKGROUND AND PURPOSE

Positive allosteric modulation of α4β2 nicotinic acetylcholine (nACh) receptors could add a new dimension to the pharmacology and therapeutic approach to these receptors. The novel modulator NS9283 was therefore tested extensively.

EXPERIMENTAL APPROACH

Effects of NS9283 were evaluated in vitro using fluorescence-based Ca(2+) imaging and electrophysiological voltage clamp experiments in Xenopus oocytes, mammalian cells and thalamocortical neurons. In vivo the compound was tested in models covering a range of cognitive domains in mice and rats.

KEY RESULTS

NS9283 was shown to increase agonist-evoked response amplitude of (α4)(3) (β2)(2) nACh receptors in electrophysiology paradigms. (α2)(3) (β2)(2) , (α2)(3) (β4)(2) and (α4)(3) (β4)(2) were modulated to comparable extents, but no effects were detected at α3-containing or any 2α : 3β stoichiometry nACh receptors. Native nACh receptors in thalamocortical neurons similarly displayed DHβE-sensitive currents that were receptive to modulation. NS9283 had favourable effects on sensory information processing, as shown by reversal of PCP-disrupted pre-pulse inhibition. NS9283 further improved performance in a rat model of episodic memory (social recognition), a rat model of sustained attention (five-choice serial reaction time task) and a rat model of reference memory (Morris water maze). Importantly, the effects in the Morris water maze could be fully reversed with mecamylamine, a blocker of nACh receptors.

CONCLUSIONS AND IMPLICATIONS

These results provide compelling evidence that positive allosteric modulators acting at the (α4)(3) (β2)(2) nACh receptors can augment activity across a broad range of cognitive domains, and that α4β2 nACh receptor allosteric modulation therefore constitutes a promising therapeutic approach to symptomatic treatment of cognitive impairment.

Status and prospects of plant virus control through interference with vector transmission

Most plant viruses rely on vector organisms for their plant-to-plant spread. Although there are many different natural vectors, few plant virus-vector systems have been well studied. This review describes our current understanding of virus transmission by aphids, thrips, whiteflies, leafhoppers, planthoppers, treehoppers, mites, nematodes, and zoosporic endoparasites. Strategies for control of vectors by host resistance, chemicals, and integrated pest management are reviewed. Many gaps in the knowledge of the transmission mechanisms and a lack of available host resistance to vectors are evident. Advances in genome sequencing and molecular technologies will help to address these problems and will allow innovative control methods through interference with vector transmission. Improved knowledge of factors affecting pest and disease spread in different ecosystems for predictive modeling is also needed. Innovative control measures are urgently required because of the increased risks from vector-borne infections that arise from environmental change.

Loop-mediated isothermal amplification for rapid detection of the causal agents of cassava brown streak disease

The causal agents of cassava brown streak disease have recently been identified as Cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus (UCBSV). Primers have been developed for rapid detection of these viruses by reverse transcription loop-mediated isothermal amplification (RT-LAMP). Performance of the RT-LAMP assays compared favourably with published RT-PCR and real-time RT-PCR methods. Furthermore, amplification by RT-LAMP is completed in 40 min and does not require thermal cycling equipment. Modification of the RT-LAMP reactions to use labelled primers allowed rapid detection of amplification products using lateral flow devices containing antibodies specific to the incorporated labels, avoiding the need for fluorescence detection or gel electrophoresis.

aepEX monitor for the measurement of hypnotic depth in patients undergoing balanced xenon anaesthesia

BACKGROUND

Previously, we showed a significant difference in the measurements of hypnotic depth by the bispectral index (BIS) and auditory-evoked potentials (AEPs) using the A-line autoregressive index during xenon anaesthesia. In the present study, we evaluate the alternative AEP-based auditory-evoked potential index (aepEX) for the measurement of hypnotic depth in patients undergoing general anaesthesia with xenon.

METHODS

Forty-two patients undergoing elective abdominal surgery were enrolled in this controlled, double-blinded, randomized, clinical study. Patients were randomized to receive either xenon (n=21) or sevoflurane anaesthesia (n=21). During anaesthesia, BIS values were recorded simultaneously with the aepEX monitoring. The anaesthetist performing the anaesthesia was blinded to the hypnotic depth monitors. After surgery, the incidence of recalls and awareness was evaluated.

RESULTS

Patients' characteristics such as gender, age, and weight did not differ between the groups. The aepEX and BIS values behaved similarly during anaesthesia. The comparison of aepEX values during xenon and sevoflurane anaesthesia revealed significantly lower aepEX values in the xenon group after 25 min [xenon: 32.9 (4.8) vs sevoflurane: 39.3 (9.0); P=0.008] and after 35 min [xenon: 31.4 (6.6) vs sevoflurane: 37.0 (6.8); P=0.012]. During anaesthesia, aepEX values correlated with the clinical evaluation of depth of anaesthesia (e.g. >20% changes of the baseline arterial pressure or heart rate, spontaneous breathing and/or intolerance of mechanical ventilation, coughing, abdominal pressing, sweating, eye tearing).

CONCLUSIONS

We found the aepEX monitor to provide index in the range of adequate depth of xenon anaesthesia, when combined with remifentanil infusion in intubated patients undergoing elective abdominal surgery.

First Report of Moroccan pepper virus on Lisianthus in Iran and Worldwide

During the last decade, lisianthus (Eustoma grandiflorum) has been introduced in Iran in the horticultural cut-flower industry. This crop is currently produced in more than 800 small greenhouses on a surface of an estimated 0.8 km² in the Pakdasht region (southeast of Teheran Province). Plants exhibiting virus-like symptoms were observed in several greenhouses in 2010. The infected plants produced yellow and necrotic spots on the leaves and became severely deformed because of a strong leaf curling and the production of shorter internodes. Flower breaking has not been observed in the blue flowering plants. Approximately 85% of the plants were apparently infected in the inspected greenhouses. Extracts of infected material inoculated onto some indicator plant species induced mosaic and leaf malformation on Nicotiana benthamiana, mottling on Capsicum annuum, necrotic lesions on Datura stramonium, chlorotic local spots on Vigna unguiculata, systemic necrotic spots on Emilia sonchifolia, chlorotic local spots on Cucumis sativus, and necrotic local lesions on Petunia hybrida. Back-inoculation of infected material on lisianthus seedlings resulted in several chlorotic spots on the inoculated leaves and a severe downward curling of the systemic infected leaves. No symptoms were observed after inoculation of Pisum sativum, Phaseolus vulgaris, Vicia faba, and Chrysanthemum spp. The virus could also be transferred from infected to healthy N. benthamiana plants by pricking leaves with a Pasteur pipette. Spherical tombusvirus-like particles of approximately 29 nm were found by transmission electron microscopy in leaf-dip and partially-purified preparations of infected N. benthamiana. Since Tomato bushy stunt virus (TBSV; genus Tombusvirus, family Tombusviridae) and Moroccan pepper virus (MPV) have been found in Iran, we studied by using ELISA whether our samples matched with TBSV. Since a negative response was obtained, two primers were designed on the basis of the available sequences of the coat protein in the GenBank (Accession No. EU27780) of an MPV isolate from soil in Fars Province, Iran. A reverse transcription (RT)-PCR of total RNA extract from infected lisianthus and N. benthamiana with the primers MPV-R (5'-TTACAACAATGTGGCATCATTG-3') and MPV-F (5'-ATGGCAATGGTAGTAAG AAAC-3') resulted in a DNA fragment of 1,176 bp. This fragment from N. benthamiana was cloned, sequenced (Accession No. HQ663881), and showed a 96% nucleotide and 99% amino acid identity with the coat protein of the soil isolate. MPV was originally found in pepper (1), tomato and pelargonium (4), pear tree (3), and surface water (2). To our knowledge, this is the first report of MPV on lisianthus in Iran and worldwide. This virus, which persists in soil, water, and plant debris, can be considered as a substantial threat for the lisianthus industry in Iran because farmers do not apply strict crop rotation or other sanitation measures. References: (1) H. U. Fischer and B. E. L. Lockhart. Phytopathology 67:1352, 1977. (2) R. Koenig and D.-E. Lesemann. Phytopathol. Z. 112:105, 1985. (3) M. Russo et al. J. Plant Pathol. 84:161, 2002. (4) H. J. Vetten and R. Koenig. 108:215, 1983.

A multi-institutional study of 3,794 patients undergoing robotic-assisted laparoscopic radical prostatectomy to determine the surgical learning curve for positive margins and operating time

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Background: The surgical learning curve for robotic assisted laparoscopic radical prostatectomy (RALP) is often cited as being shorter than for other surgical modalities. However, while this appears true with regards to surgical safety, the learning curve for more refined variables like positive surgical margin (PSM) rate and operative time (OT) is not well established. Our objective was to assess the surgical learning curve for RALP in terms of these parameters.

Methods: We performed a retrospective cohort study of 3,794 patients who underwent RALP between Jan 2003 and Sep 2009 by three surgeons (DL, PW, AKT) from three centers (UPenn, Karolinska, Cornell). Mean overall PSM rates and mean overall OT were calculated for all three surgeons at intervals of 50 RALPs per surgeon, and learning curves for these means were fit using a loess method. R version 2.71 was used for all statistical analysis.

Results: The learning curve for PSM rates for all patients demonstrated improvements that continued with greater surgeon experience, with over 1,600 cases required to get a PSM rate <10%. When only pT3 patients were evaluated, the learning curve started to plateau after 1,000-1,500 cases. Mean OT plateaued after 750 cases although with further surgical experience the OTs started to climb again.

Conclusions: The learning curve for RALP is not as short as previously thought, and a large number of cases are needed to get PSM rates and OTs to a minimum. This suggests that RALP should be performed by high volume surgeons in order to optimize patient outcomes.

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Identification of Iris yellow spot virus on Leek (Allium porrum) in Sri Lanka

Leek (Allium porrum) has become one of the major leafy vegetable export crops in Sri Lanka during last few years. This year-round crop is cultivated in open fields at elevations between 1,000 and 2,000 m on approximately 1,600 ha with a production of 27,000 t per year (2). In August 2009, straw-colored spots (2 to 3 mm in diameter), surrounded by a greenish halo and a necrotic area, resembling symptoms to those caused by Iris yellow spot virus (IYSV) were observed on leek in Kandapola in the Nuwara Eliya District. Additional thrips damage consisting of silver-colored spots was observed on all plants. IYSV (family Bunyaviridae, genus Tospovirus) was first described and characterized in the Netherlands in 1998 (1). During the last few years, this virus was reported from Australia, Brazil, Chile, France, Germany, Guatemala, India, Israel, New Zealand, Peru, Reunion Island, Serbia, South Africa, Spain, the United States (4), and Japan. Collected samples were initially analyzed for IYSV infections using antisera raised against nucleocapsid (N) protein in a double-antibody sandwich (DAS)-ELISA. The presence of IYSV was confirmed by a reverse transcription (RT)-PCR using IYSV-F-373 (5'CTGCGGGCTTCTCTGG3') and IYSV-R-779 (5'GACTCACCAATGTCTTCAAC3') primers that amplify a 400-bp fragment of the N gene. The entire N gene was not obtained when specific primers were used to retrieve the complete N gene. Four nucleotides of the reverse primer GAAAGATAGATATAATTAA (indicated in bold) did not match with sequence at the 3'end of the N gene. Hence, to obtain the remaining parts of the N gene, the primers UHP (5'CACTGGATCCTTTTGTTTTTGTTTTTTG3') and Asian Termini (5'CCCGGATCCAGAGCAATCGAGGY3') (3) were combined with IYSV-F and IYSV-R. The obtained amplicons were cloned into pGEM-T easy vector and sequenced. The N gene sequence has been deposited at the NCBI/GenBank (Accession No. GU901211). The deduced N protein sequence(s) were compared with other IYSV N protein sequences available in the GenBank and showed a 92% protein identity with the Brazilian strain (IYSV-BR) and 97% with the Dutch strain (IYSV-NL) with Accession Nos. AAF04199 and AAB61923, respectively. No data on the thrips vector species or on the disease incidence have been collected. The presence of IYSV in Sri Lanka can potentially be considered as a threat for the export of leek. To our knowledge, this is the first report that IYSV occurs in Sri Lanka. References: (1) I. Cortêz et al. Phytopathology 88:1276, 1998. (2) Department of Census and Statistics Sri Lanka. Retrieved from http://www.statistics.gov.lk , 2009. (3) A. Hassani-Mehraban et al. Phytopathology 95:852, 2005. (4) H. R. Pappu et al. Virus Res. 141:219, 2009.

Identification and Incidence of Iris yellow spot virus, a New Pathogen in Onion and Leek in Greece

Iris yellow spot virus (IYSV; genus Tospovirus, family Bunyaviridae) is an emerging and serious pathogen affecting several Allium spp. worldwide (2). The virus causes straw-colored, chlorotic or necrotic lesions that coalesce, occasionally resulting in an extensive necrosis on onion (A. cepa L.) leaves. From February to June 2008, 530 onion and 439 leek (A. porum L.) leaf samples showing a variety of lesions were collected from different areas of Greece. All plants sampled were infested with Thrips tabaci Lindeman, the sole thrips species identified as the vector of this virus. Samples were analyzed by double-antibody sandwich (DAS)-ELISA using polyclonal antibodies against the N protein of IYSV (Laboratory of Virology, Wageningen Agricultural University). A higher percentage of onion samples than leek samples were infected, with IYSV detected in 36, 44, 23.7, 61.7, 10, 55, 15.3, and 9.4% of onion samples from the prefectures of Evros, Heraklion, Kavala, Magnissia, Pella, Rodopi, Thessaloniki, and Viotia, respectively, and in 5, 0, 0, 9.3, and 13% of leek samples from Evros, Heraklion, Magnissia, Pella, and Thessaloniki, respectively. No leek samples were tested from Kavala, Rodopi, and Viotia. Sap extracts from some positive samples were mechanically inoculated onto Nicotiana benthamiana leaves, and infected plants developed typical IYSV symptoms and were positive in DAS-ELISA, confirming transmission from the field samples. Viral RNA was extracted from ELISA-positive onion and leek samples and an ~800-bp amplicon was obtained from both hosts by reverse-transcription (RT)-PCR and N-gene primers derived from IYSV (IY1: 5'-CCCGAGGATCCATGGCTACCGTTAGGG-3' and IY2: 5'-CCCGAGGATCCAAATTAATTATATCTATCTTTCTTGG-3') (1). These amplicons were cloned and sequenced (GenBank Accession No. FJ785835) and nucleotide sequence comparisons showed a 98 to 99% identity with a Dutch isolate of IYSV (GenBank Accession No AF001387). The virus was transmitted among onion seedlings in the laboratory using a leek population of T. tabaci. Infected seedlings, as determined by DAS-ELISA, developed symptoms similar to those observed in the field samples. To our knowledge, this is the first report of IYSV in Greece; however, the virus seems already to be very well established. References: (1) I. Cortez et al. Phytopathology 88:1276, 1998. (2) D. Gent et al. Plant. Dis. 90:1468, 2006.

Access to and utilisation of health services for the poor in Uganda: a systematic review of available evidence

Inequalities in the burden of disease and access to health care is a prominent concern in Uganda and other sub-Saharan African countries. This is a systematic review of socio-economic differences in morbidity and access to health care in Uganda. It includes published studies from electronic databases and official reports from surveys done by government, bilateral and multilateral agencies and universities. The outcome measures studied were: the distribution of HIV/AIDS; maternal and child morbidity; and access to and utilisation of health services for people belonging to different socio-economic and vulnerability groups. Forty-eight of 678 identified studies met our inclusion criteria. Results indicate that the poor and vulnerable experience a greater burden of disease but have lower access to health services than the less poor. Barriers to access arise from both the service providers and the consumers. Distance to service points, perceived quality of care and availability of drugs are key determinants of utilisation. Other barriers are perceived lack of skilled staff in public facilities, late referrals, health worker attitude, costs of care and lack of knowledge. Longitudinal and controlled studies are needed to see if strategies to improve access to services reach the poor.

Occurrence of Tomato spotted wilt virus in Stevia rebaudiana and Solanum tuberosum in Northern Greece

Tomato spotted wilt virus (TSWV) (genus Tospovirus, family Bunyaviridae) was first reported in Greece during 1972 (3) and currently is widespread in the central and northern part of the country infecting several cultivated and wild plant species (1,2). In June 2006, virus-like symptoms similar to those caused by TSWV were observed on sweet honey leaf (Stevia rebaudiana (Bertoni) Bertoni, [synonym Eupatorium rebaudianum Bertoni], family Asteraceae) plants in an experimental field in the prefecture of Kilkis and on potato (Solanum tuberosum, family Solanaceae) plants growing close to tobacco in the prefecture of Kozani in northern Greece. Diseased S. rebaudiana plants expressed chlorotic and necrotic rings and line patterns on systemically infected leaves and occasionally a general chlorosis or dwarfing of the plant. Potato plants expressed only necrotic rings or lesions and a mild plant dwarfing. Seven percent of the S. rebaudiana plants, but only 0.1% of the potato plants, were showing symptoms. TSWV was detected by ELISA using polyclonal antisera in all symptomatic plants of both species, but those plants tested negative for Potato Y virus (PVY), Cucumber mosaic virus (CMV), Alfalfa mosaic virus (AMV), and Potato leafroll virus (PLRV); all viruses known to occur in these areas. Sap from symptomatic plants was used to mechanically inoculate Petunia × hybrida cv. Blue magic, Nicotiana tabacum cvs. Samsun NN and Basmas, N. benthamiana, N. glutinosa, N. rustica, Datura stramonium, and Physalis floridana. Sap from both S. rebaudiana and potato produced typical symptoms of TSWV on the diagnostic test plants; all Nicotiana species and cultivars, as well as D. stramonium and P. floridana, reacted with chlorotic and necrotic lesions on the inoculated leaves followed by systemic mosaic and mottling of the leaves. None of the isolates produced systemic infection on P. × hybrida. Adult thrips, identified as Thrips tabaci, were collected from infected plants of both hosts in the field and determined to be infected with TSWV by the petunia leaf disc method (4). Symptoms observed in the field on both hosts where reproduced in the laboratory after infestation of healthy plants with TSWV-infected individuals from a tobacco population of T. tabaci. To our knowledge, this is the first official report of a TSWV infection in S. rebaudiana. Potato is a known host for TSWV, however, to our knowledge, this is the first natural infection detected in Greece. References: (1) E. K. Chatzivassiliou et al. Ann. Appl. Biol. 137:127, 2000. (2) E. K. Chatzivassiliou et al. Plant Dis. 85:40, 2001. (3) J. P. Tsakiridis and G. V. Gooding, Jr. Phytopathol. Mediterr. 11:42, 1972. (4) I. Wijkamp and D. Peters. Phytopathology 83:986,1993.

Multicenter evaluation of the new Abbott RealTime assays for quantitative detection of human immunodeficiency virus type 1 and hepatitis C virus RNA

The analytical performances of the new Abbott RealTime hepatitis C virus (HCV) and human immunodeficiency virus type 1 viral load assays were compared at nine laboratories with different competitor assays. These included the Abbott LcX, Bayer Versant bDNA, Roche COBAS Amplicor, and Roche COBAS TaqMan assays. Two different protocols used during the testing period with and without a pre-m1000 RNA isolation spin were compared. The difference proved to be nonsignificant. A uracil-N-glycosylase (UNG) contamination control option in the HCV test for previous Roche COBAS Amplicor users was evaluated. It proved to decrease amplicon carryover by 100-fold independent of the amplicon input concentration. The protocol including UNG proved to overcome problems with false-positive negative controls. Comparison with other assays revealed only minor differences. The largest difference was observed between the Abbott HCV RealTime assay and the Roche COBAS Amplicor HCV Monitor version 2.0 assay.

Molecular and biological comparison of two Tomato yellow ring virus (TYRV) isolates: challenging the Tospovirus species concept

Two strains of Tomato yellow ring virus (TYRV, genus Tospovirus), one from tomato (referred to as TYRV-t) and the other from soybean and potato (denoted TYRV-s), collected from different geographical regions in Iran, were compared. Their genomic S RNA segments differed in size by 55 nucleotides. Comparison of the S RNA intergenic regions revealed the absence of a stretch of 115 nucleotides within the S RNA segment of TYRV-s and, conversely, of 56 nts in that of TYRV-t, apparently a stable genetic difference as it was also found in another isolate of TYRV-s collected from potato. Sequence comparison of the N protein ORFs revealed an identity of 92% between the N proteins of both strains, and the observed strong cross-reaction of TYRV-s in DAS-ELISA with a polyclonal antiserum directed against the TYRV-t N protein confirmed this high identity. Host range analysis revealed several differences, e.g. TYRV-s, but not TYRV-t, being able to systemically infect Nicotiana species, and TYRV-s being localised in tomato. The observed molecular and biological differences of both viruses call into question the currently used criteria for Tospovirus species demarcation.

A 13-week dietary toxicity and toxicokinetic study with l-theanine in rats

This study was conducted to evaluate the safety of l-theanine (Suntheanine) when administered as a dietary admixture to male and female Crl:CD (SD)GS BR rats at concentrations providing doses of 0, 1500, 3000 or 4000 mg/kg bw/day for 13 weeks. The study design was consistent with OECD Guideline 408 and USFDA Redbook II (1993) and GLP. There were no consistent, statistically significant treatment-related adverse effects on behavior, morbidity, mortality, body weight, food consumption and efficiency, clinical chemistry, hematology, or urinalysis. There were no consistent treatment-related adverse effects in gross pathology, organ weights or ratios or histopathology. The increased incidence of renal tubular cell adenomas in high-dose females only were not consistent with the characteristics of a renal carcinogen (due to early onset and low number of animals affected) but were more consistent with a genetic predisposition than with direct organ toxicity. The no-observed-adverse-effect-level (NOAEL) was 4000 mg/kg bw/day, the highest dose tested.

A phase I study of axitinib (AG-013736), a potent inhibitor of VEGFRs, in combination with gemcitabine (GEM) in patients (pts) with advanced pancreatic cancer

13092

Background: Axitinib (AG-013736) is a novel small molecule inhibitor of the receptor tyrosine kinases with picomolar potency against VEGFR 1, 2 & 3 and nanomolar potency against PDGFR-beta and KIT. A phase I study in solid tumors identified 5 mg BID as the therapeutic dose; a phase II study in renal cell cancer demonstrated significant efficacy with a response rate (RR) of 46% (Rini et al, ASCO 2005). This study examined the safety, PK and preliminary efficacy of AG-013736 (AG) in combination with gemcitabine (GEM) as first-line therapy for advanced pancreatic cancer. Methods: A randomized phase II study was preceded by a phase I component. All patients (pts) in the phase I portion received 1000 mg/m2 GEM by 30-minute infusion on days 1, 8, and 15 followed by one week of rest from treatment. AG 5 mg p.o. BID was given beginning Cycle 1, Day 3 (C1D3). Eligible pts had no prior chemotherapy for advanced disease, ECOG 0–2, and no previous treatment with VEGF/VEGFR inhibitors, or anti-angiogenesis treatment. Full PK profiles were collected on C1D1 (GEM alone), C1D14 (steady state, AG alone), and C1D15 (GEM + AG). In the phase II trial, pts are randomized to AG or AG plus GEM beginning C1D1. Results: 8 pts were treated on the phase I portion of this trial. Toxicity: The primary Gr. 3/4 toxicity was hematologic: Gr. 4 anemia and Gr.3 thrombocytopenia in 1 pt and Gr. 3 neutropenia in 1 pt requiring a dose reduction for GEM in Cycle 3. Gr. 2 non-hematologic adverse events include pruritus (1 pt), abdominal pain (2 pts), epigastric pain (1 pt), melena (1 pt), and asthenia (2 pts). Gr. 2 hypertension was observed in 3 pts. Efficacy: Radiological assessment suggests 2 pts with partial response and 4 pts with stable disease: response assessments are ongoing. The median number of cycles is 3 [1,6]. Treatment for 4 pts is still ongoing: Cycle 6 (2 pts) and Cycle 2 (2 pts). Conclusions: This combination is safe and appears to be an effective treatment for advanced pancreatic cancer with significant tumor regression observed in 2 pts. Therapy was well tolerated with manageable toxicity. Additional investigation of AG-013736 in combination with GEM in the phase II setting for advanced pancreatic cancer is warranted.

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