Log D versus HPLC derived hydrophobicity: The development of predictive tools to aid in the rational design of bioactive peptoids.

Hydrophobicity has proven to be an extremely useful parameter in small molecule drug discovery programmes given that it can be used as a predictive tool to enable rational design. For larger molecules, including peptoids, where folding is possible, the situation is more complicated and the average hydrophobicity (as determined by RP-HPLC retention time) may not always provide an effective predictive tool for rational design. Herein, we report the first ever application of partitioning experiments to determine the log D values for a series of peptoids. By comparing log D and average hydrophobicities we highlight the potential advantage of employing the former as a predictive tool in the rational design of biologically active peptoids.

A practical method for the synthesis of peptoids containing both lysine-type and arginine-type monomers.

Peptoids are a promising class of peptidomimetics that exhibit the key chemical and physical properties of peptides but without being hampered by susceptibility towards enzymatic degradation. Biologically active peptoids are often designed to be amphipathic in nature, consisting of hydrophobic monomers interspersed with either cationic lysine-type or arginine-type monomers. Access to amphipathic peptoids that contain both lysine-type and arginine-type monomers is highly desirable as it offers a route to further modulate the biological properties of this class of molecule. However, the lack of a suitable synthetic route to prepare mixed cationic peptoids has meant that their biological potential has remained almost largely unexplored. Herein, we present an efficient synthetic route that can be used to access novel cationic peptoids containing both lysine-type and arginine-type monomers within the same sequence.

Total chemical synthesis of lassomycin and lassomycin-amide.

Herein we report a practical synthetic route to the lasso peptide lassomycin () and C-terminal variant lassomycin-amide (). The biological evaluation of peptides and against Mycobacterium tuberculosis revealed that neither had any activity against this bacterium. This lack of biological activity has led us to propose that naturally occurring lassomycin may actually exhibit a standard lasso peptide threaded conformation rather than the previously reported unthreaded structure.

The spread of non-OIE-listed avian diseases through international trade of chicken meat: an assessment of the risks to New Zealand.

Twelve avian diseases are listed by the World Organisation for Animal Health (OIE), although more than 100 infectious diseases have been described in commercial poultry. This article summarises a recent assessment of the biosecurity risks posed by non-listed avian diseases associated with imports of chilled or frozen chicken meat and meat products into New Zealand. Following the guidelines described in Chapter 2.1 of the OIE Terrestrial Animal Health Code, avian adenovirus splenomegaly virus, avian paramyxovirus-2 (APMV-2), Bordetella avium, Mycoplasma spp., Ureaplasma spp., Ornithobacterium rhinotracheale, Riemerella anatipestifer, and Salmonella arizonae have been identified as hazards. However, of all the non-listed avian diseases discussed here, only APMV-2 and S. arizonae are assessed as being risks associated with the commercial import of chicken meat into New Zealand. Specific control measures may have to be implemented to mitigate such risks. This conclusion is likely to reflect both the high-health status of New Zealand poultry and the threat posed by these infectious agents to New Zealand's unique population of native psittacine species.

Quantitative risk assessment of the likeihood of introducing porcine reproductive and respiratory syndrome virus into New Zealand through the importation of pig meat.

A quantitative model was developed to estimate the likelihood of an incursion of porcine reproductive and respiratory syndrome virus (PRRSV) into New Zealand through the importation of fresh consumer-ready cuts of pig meat. A sensitivity analysis of all the inputs used in this model illustrated the importance of correctly modelling the available 'dose-response' data, and a mechanistic Beta-Poisson model was shown to be the most appropriate method for this in the authors' assessment. The output of this model predicts an average of approximately 1,200 years between PRRSV introductions resulting in primary infections in New Zealand. Given the uncertainties in the model, there is 95% confidence that this time period ranges from 52 to 6,200 years. The values chosen in this model are considered to provide a conservative estimate of the likelihood of introducing PRRSV into New Zealand via the importation of fresh pork.

Association between Migraine and Quality of Life, Mental Health, Sleeping Disorders, and Health Care Utilization Among Older African American Adults.

PURPOSE: This study examines the associations between migraine headaches, well-being, and health care use among a sample of underserved older African American adults. Controlling for relevant variables, the association between migraine headaches and (1) health care utilization, (2) health-related quality of life (HRQoL), and (3) physical and mental health outcomes was examined. METHODS: Our sample included 760 older African American adults from South Los Angeles recruited through convenience and snowball sampling. In addition to demographic variables, our survey included validated instruments, such as the SF-12 QoL, Short-Form McGill Pain Questionnaire, and the Geriatric Depression Scale. Data analysis included 12 independent multivariate models using multiple linear regression, log transferred linear regression, binary and multinomial logistic regression, and generalized linear regression with Poisson distribution. RESULTS: Having migraine was associated with three categories of outcomes: (1) higher level of health care utilization measured by (i) emergency department admissions and (ii) number of medication use; (2) lower level of HRQoL and health status measured by (i) lower self-rated health (ii) physical QoL, and (iii) mental QoL; and (3) worse physical and mental health outcomes measured by (i) higher number of depressive symptoms, (ii) higher level of pain, (iii) sleep disorder, and (iv) being disabled. CONCLUSIONS: Migraine headache significantly was associated with quality of life, health care utilization, and many health outcomes of underserved African American middle-aged and older adults. Diagnoses and treatments of migraine among underserved older African American adults require multi-faceted and culturally sensitive interventional studies.

SNCA, MAPT, and GSK3B in Parkinson disease: a gene-gene interaction study.

BACKGROUND AND PURPOSE: Recent evidence suggests that variation in the SNCA, MAPT, and GSK3B genes interacts in affecting risk for Parkinson disease (PD). In the current study, we attempt to validate previously published findings, evaluating gene-gene interactions between SNCA, MAPT, and GSK3B in association with PD. METHODS: Three Caucasian PD patient-control series from the United States, Ireland, and Norway (combined n = 1020 patients and 1095 controls) were genotyped for SNCA rs356219, MAPT H1/H2-discriminating SNP rs1052553, and GSK3B rs334558 and rs6438552. RESULTS: Our findings indicate that as previously reported, the SNCA rs356219-G allele and MAPT rs1052553 (H1 haplotype) were both associated with an increased risk of PD, whilst contrary to previous reports, GSK3B variants were not. No pair-wise interaction was observed between SNCA, MAPT, and GSK3B; the risk effects of SNCA rs356219-G and MAPT rs1052553-H1 were seen in a similar manner across genotypes of other variants, with no evidence suggesting synergistic, antagonistic, or deferential effects. CONCLUSIONS: In the Caucasian patient-control series examined, risk for PD was influenced by variation in SNCA and MAPT but not GSK3B. Additionally, those three genes did not interact in determining disease risk.

The spread of pathogens through trade in poultry meat: overview and recent developments.

Increasing international trade in poultry meat presents an opportunity for the global dissemination of poultry disease. However, it would be very unfortunate if expanding world trade resulted in animal diseases being used as unjustified non-tariff trade barriers. For those avian diseases currently listed by the World Organisation for Animal Health, the current evidence suggests that only highly pathogenic avian influenza, Newcastle disease, and (for chicken meat) infectious bursal disease should be considered likely to be spread though trade in this commodity.

The spread of pathogens through trade in poultry hatching eggs: overview and recent developments.

The international trade in poultry hatching eggs could potentially facilitate the global dissemination of poultry disease. Provided the guidelines of the World Organisation for Animal Health (OIE) on breeding flock hygiene are followed, of those avian diseases currently listed by the OlE, only highly pathogenic avian influenza (HPAI), Newcastle disease (ND), and avian mycoplasmosis (caused by Mycoplasma gallisepticum or M. synoviae) should be considered likely to be spread though trade in this commodity. Furthermore, the impact of HPAI and ND on egg production and hatchability will constrain the potential for these agents to be spread by poultry hatching eggs.

The spread of pathogens through trade in pig meat: overview and recent developments.

A number of animal diseases can be transmitted to pigs via meat if the animals are fed scraps of meat imported from infected countries. For this reason, garbage feeding of pigs is regulated in many countries. The major porcine diseases recognised as being significant for this transmission pathway are foot and mouth disease, African swine fever, classical swine fever and swine vesicular disease. The World Organisation for Animal Health Terrestrial Animal Health Code (the Terrestrial Code) offers risk management recommendations for meat from countries where these diseases are present. However, there is no Terrestrial Code chapter on porcine reproductive and respiratory syndrome (PRRS), a relatively new viral disease of pigs which, since its recognition in the 1990s, has become endemic in most pig-producing countries. This paper assesses the risk of spread of PRRS virus through trade in pig meat, and concludes that the likelihood of its transmission by this pathway is negligible.

Association of the MAPT locus with Parkinson's disease.

BACKGROUND AND PURPOSE: Whilst an association between the tau gene (MAPT)-containing H1 haplotype and supranuclear gaze palsy (PSP) has long been recognized, the effect of H1 on risk for Parkinson's disease (PD) has remained more contentious. METHODS: Herein, we examined the association of H1 and PD in three Caucasian PD patient-control series from Ireland, Norway, and the US (combined: n = 2619), by genotyping two H1/H2 single nucleotide polymorphisms (SNPs) in MAPT (rs1052553) and in the Saitohin gene (rs62063857) and one H1-specific SNP (rs242557). RESULTS: We identified a significant association between H1/H2 and risk of PD (rs1052553 OR: 1.43, CI: 1.23-1.64; rs62063857 OR: 1.45, CI: 1.27-1.67), but no effect of the H1-specific SNP rs242557 (OR: 0.92, CI: 0.82-1.03). CONCLUSIONS: Our findings show that the H1 haplotype is a significant risk factor for PD. However, one H1-specific SNP (rs242557) previously implicated in PSP did not alter the risk of PD, indicating that distinct H1 sub-haplotypes probably drive the associations with PD and PSP.

Global changes in the hippocampal proteome following exposure to an enriched environment.

Exposure to an enriched environment promotes neurochemical, structural and neurophysiological changes in the brain and is associated with enhanced synaptic plasticity and improved hippocampal-dependent learning. Using a global proteomics-based approach we have now been able to reveal the altered expression of a diverse range of hippocampal proteins following exposure to an enriched environment. Male Hooded Lister rats (8 weeks) were subjected to a 6-week regimen in which they were housed in either non-enriched (open field) or enriched conditions (toys, wheels etc.). Whole protein extracts from stratum pyramidale and stratum radiatum of area CA1 were then isolated and subjected to differential gel electrophoresis [McNair K, Davies CH, Cobb SR (2006) Plasticity-related regulation of the hippocampal proteome. Eur J Neurosci 23(2):575-580]. Of the 2469 resolvable protein spots detected in this study, 42 spots (1.7% of the detectable proteome) derived from predominantly somatic fractions and 32 proteins spots from dendritic fractions (1.3% of detectable proteome) were significantly altered in abundance following exposure to an enriched environment (somatic: 14 increased/28 decreased abundance, range -1.5 to +1.4-fold change; dendritic: 16 increased, 16 decreased abundance, range -1.6 to +3.0-fold change). Following in-gel tryptic digestion and Maldi-Tof/Q-star mass spectrometry, database searching revealed the identity of 50 protein spots displaying environmental enrichment-related modulation of expression. Identified proteins belonged to a variety of functional classes with gene ontology analysis revealing the majority (>70%) of regulated proteins to be part of the energy metabolism, cytoplasmic organization/biogenesis and signal transduction processes.

Exploring the links between peptoid antibacterial activity and toxicity.

Peptoids are a promising class of antimicrobial agents with reported activities against a range of both Gram-positive and Gram-negative bacteria, fungi and most recently parasites. However, at present the available toxicity data is somewhat limited and as such rationally designing effective antimicrobial peptoids can be challenging. Herein, we present the toxicity profiling of a series of linear peptoids against mammalian cell lines (HaCaT and HepG2). The cytotoxicity of the peptoid library has then been correlated with their antibacterial properties against Gram-positive and Gram-negative bacteria and also to the hydrophobicity of the peptoid sequences. The work presented provides valuable data to aid in the future rational design of antimicrobial peptoids.

Role of ligand in antibody-directed endocytosis of liposomes by human T-leukemia cells.

The rate of uptake and intracellular processing of ligand-directed drug carriers may depend heavily on the endocytic pathway of the target antigen. We examined the role of the target antigen and type of antibody-liposome linkage in determining endocytosis of liposomes by three human T-cell leukemias, Jurkat, CEM, and Molt-4. Liposome-cell binding and internalization over time were studied using two independent assays for intracellular delivery of liposome contents: a new fluorescence assay using a pH-sensitive fluorescent dye; and a growth inhibition assay for delivery of cytotoxic drug, methotrexate-gamma-aspartate. Liposomes targeted against the transferrin receptor showed greater surface binding, internalization, and growth inhibition than liposomes targeted against the T-cell surface antigens, CD2, CD3, or CD5. Furthermore, liposomes made by conjugating the targeting antibody directly to the liposome surface were more efficiently internalized and retained than were liposomes linked to antibody-coated cells via Protein A. Selection of the type of antibody-liposome conjugate as well as the appropriate surface receptor to facilitate endocytosis is essential in antibody-directed drug treatment of cancer.

Neurologic complications of cocaine abuse.

Over a 24-month period we evaluated 14 patients with neurologic disease associated with cocaine abuse. Five patients developed previously unreported complications: anterior spinal artery syndrome, lateral medullary syndrome, transient ischemic attacks in the middle cerebral artery and vertebrobasilar artery territories, and partial motor seizures. The recent availability of crack has led to a great increase in neurologic problems associated with the use of this drug.

Coincident activation of mGluRs and mAChRs imposes theta frequency patterning on synchronised network activity in the hippocampal CA3 region.

Activation of metabotropic glutamate receptors (mGluRs) with the broad spectrum mGluR agonist 1S,3R ACPD (10-50 microM) induced spontaneous field potentials at low frequencies ('burst-mode' activity; <1 Hz) in the CA3 region of rat hippocampal slices. At higher concentrations (100-400 microM) ACPD switched this form of activity to a second, more complex pattern of activity in which intermittent episodes of theta frequency oscillations predominated ('theta-mode' activity; 4-14 Hz). Both patterns of activity were evoked by selective activation of group I mGluRs and, in particular, could be induced by activation of mGluR5 alone using the subtype selective agonist CHPG (0.5-5 mM). In contrast, activation of group II mGluRs (DCG IV; 100 microM) produced only burst-mode behaviour whilst activation of group III mGluRs (L-AP4; 100 microM) did not result in synchronised network activity. Concurrent extra- and intracellular recordings demonstrated that this mGluR-induced theta-mode activity represented the synchronous firing of CA3 pyramidal cells and that it shared a similar temporal signature to that generated by activation of muscarinic acetylcholine receptors (mAChRs). Furthermore, application of mGluR and mAChR agonists at concentrations sufficient to produce only burst-mode activity when applied individually, produced theta-mode activity when co-applied. These data suggest that the level of activation of different mGluRs and mAChRs crucially determine the pattern of rhythmical network activity generated in the hippocampal CA3 network. These results also indicate that individual receptor subtypes (i.e. mGluR5) can initiate patterns of coherent network activity but that interactions between the cholinergic and glutamatergic transmitter systems may also be important factors in governing the temporal patterning of hippocampal network activity.

Activation of Ih is necessary for patterning of mGluR and mAChR induced network activity in the hippocampal CA3 region.

Neuronal networks of the hippocampal CA3 region generate stereotyped patterns of electrical activity in response to activation of metabotropic glutamate receptors (mGluRs) or muscarinic acetylcholine receptors (mAChRs) that consist of intermittent episodes of prolonged oscillatory activity. In light of the slow kinetics of such network responses, we investigated the possible contribution of the hyperpolarisation-activated inward current (I(h)) in the generation and maintenance of hippocampal oscillatory states. Hippocampal 'mini-slice' experiments in which the main subfields of the hippocampus were isolated by transection of the connecting afferents revealed that the CA3 region was the primary generator of both mGluR and mAChR-mediated network responses. Subsequent patch-clamp experiments confirmed the presence of a prominent hyperpolarisation-activated inward current in the principal cells of the CA3 region that was sensitive to caesium chloride and the selective I(h) blocker ZD-7288.Furthermore, in the presence of mAChR or mGluR agonists these cells exhibited a slow membrane potential oscillation that was independent of AMPA receptor-mediated synaptic transmission. Blockade of I(h) suppressed this oscillation as well as mGluR and mAChR-induced theta based intermittent network oscillatory behaviour. These data support the idea that the I(h) pacemaker current is important in the generation of patterned neuronal activities in the hippocampus.

Regulation of depolarizing GABA(A) receptor-mediated synaptic potentials by synaptic activation of GABA(B) autoreceptors in the rat hippocampus.

The role of GABA(B) autoreceptors in the regulation of GABA(A) and GABA(B) receptor-mediated inhibitory post-synaptic potentials (IPSPs) during repetitive synaptic activation has been established. In the present study the role of these receptors in the regulation of depolarising GABA(A) receptor-mediated synaptic potentials (DPSP(A)s) in the CA1 region of the hippocampus is documented. Following blockade of AMPA and NMDA receptor-mediated synaptic excitation, DPSP(A)s could be evoked by a single stimulus. The size of this response was enhanced by increasing the stimulus number (1-10 shocks) or stimulus frequency (10-100 Hz). Conversely, the amplitude of the DPSP(A) was dramatically reduced by a priming pulse (single shock) or priming burst (four shocks) delivered 200 ms beforehand. This activity-dependent depression was eliminated by the GABA(B) receptor antagonist CGP 35348 (1 mM). As such, GABA(B) autoreceptor-mediated regulation of DPSP(A)s prevented a pronounced, potentially epileptogenic, DPSP(A) from occurring during theta burst stimulation. Thus, during repetitive stimulation, activation of GABA(B) autoreceptors not only enables a transient reduction in GABA(A) receptor-mediated synaptic inhibition sufficient to enable NMDA receptor-dependent synaptic plasticity [Davies, C.H., Collingridge, G.L., 1996. J. Physiol. 496.2, 451-470] but also prevents the development of a potentially pathogenic depolarising GABA-mediated synaptic potential.

Synaptic effects of identified interneurons innervating both interneurons and pyramidal cells in the rat hippocampus.

GABAergic interneurons sculpt the activity of principal cells and are themselves governed by GABAergic inputs. To determine directly some of the sources and mechanisms of this GABAergic innervation, we have used dual intracellular recordings with biocytin-filled microelectrodes and investigated synaptic interactions between pairs of interneurons in area CA1 of the adult rat hippocampus. Of four synaptically-coupled interneuron-to-interneuron cell pairs, three presynaptic cells were identified as basket cells, preferentially innervating somata and proximal dendrites of pyramidal cells, but one differing from the other two in the laminar distribution of its dendritic and axonal fields. The fourth presynaptic interneuron was located at the border between strata lacunosum moleculare and radiatum, with axon ramifying within stratum radiatum. Action potentials evoked in all four presynaptic interneurons were found to elicit fast hyperpolarizing inhibitory postsynaptic potentials (mean amplitude 0.35 +/- 0.10 mV at a membrane potential of -59 +/- 2.8 mV) in other simultaneously recorded interneurons (n=4). In addition, three of the presynaptic interneurons were also shown to produce similar postsynaptic responses in subsequently recorded pyramidal cells (n=4). Electron microscopic evaluation revealed one of the presynaptic basket cells to form 12 synaptic junctions with the perisomatic domain (seven somatic synapses and five synapses onto proximal dendritic shafts) of the postsynaptic interneuron in addition to innervating the same compartments of randomly-selected local pyramidal cells (50% somatic and 50% proximal dendritic synapses, n=12). In addition, light microscopic analysis also indicated autaptic self-innervation in basket (12 of 12) and bistratified cells (six of six). Electron microscopic investigation of one basket cell confirmed six autaptic junctions made by five of its boutons. Together, these data demonstrate that several distinct types of interneuron have divergent output to both principal cells and local interneurons of the same (basket cells) or different type. The fast synaptic effects, probably mediated by GABA in both postsynaptic interneurons and principal cells are similar. These additional sources of GABA identified here in the input to GABAergic cells could contribute to the differential temporal patterning of distinct GABAergic synaptic networks.

Hearing loss and temporal bone structure in achondroplasia.

Characteristic temporal bone changes have recently been defined by high resolution CT in nine patients with achondroplasia (Cobb et al., Am J Neuroradiol 9:1195, 1988). These included narrowing of the skull base and "towering" petrous ridges resulting in abnormal orientation of the inner and middle ear structures. In order to determine whether these morphologic changes are the cause of the hearing deficit in achondroplasia, audiometric studies and ENT evaluation were performed in eight of the nine patients. All had a history of frequent otitis media and four had experienced tympanic membrane tube insertion. Three patients had significant sensorineural hearing loss, two had conductive hearing loss and one patient had combined hearing loss. None of the temporal bone morphologic changes were found to be correlated with the degree of either sensorineural or conductive hearing loss. Fusion of the ossicular chain was not present in any of our cases. Appropriate treatment of frequent acute otitis media and early awareness of middle ear effusions and conductive hearing loss in children with achondroplasia may be of great importance in preventing permanent hearing loss.