Structure-Activity Studies of Cysteine-Rich α-Conotoxins that Inhibit High-Voltage-Activated Calcium Channels via GABA(B) Receptor Activation Reveal a Minimal Functional Motif.

α-Conotoxins are disulfide-rich peptides that target nicotinic acetylcholine receptors. Recently we identified several α-conotoxins that also modulate voltage-gated calcium channels by acting as G protein-coupled GABA(B) receptor (GABA(B)R) agonists. These α-conotoxins are promising drug leads for the treatment of chronic pain. To elucidate the diversity of α-conotoxins that act through this mechanism, we synthesized and characterized a set of peptides with homology to α-conotoxins known to inhibit high voltage-activated calcium channels via GABA(B)R activation. Remarkably, all disulfide isomers of the active α-conotoxins Pu1.2 and Pn1.2, and the previously studied Vc1.1 showed similar levels of biological activity. Structure determination by NMR spectroscopy helped us identify a simplified biologically active eight residue peptide motif containing a single disulfide bond that is an excellent lead molecule for developing a new generation of analgesic peptide drugs.

Estimating the Incidence of Acute Infectious Intestinal Disease in the Community in the UK: A Retrospective Telephone Survey.

OBJECTIVES: To estimate the burden of intestinal infectious disease (IID) in the UK and determine whether disease burden estimations using a retrospective study design differ from those using a prospective study design. DESIGN/SETTING: A retrospective telephone survey undertaken in each of the four countries comprising the United Kingdom. Participants were randomly asked about illness either in the past 7 or 28 days. PARTICIPANTS: 14,813 individuals for all of whom we had a legible recording of their agreement to participate. OUTCOMES: Self-reported IID, defined as loose stools or clinically significant vomiting lasting less than two weeks, in the absence of a known non-infectious cause. RESULTS: The rate of self-reported IID varied substantially depending on whether asked for illness in the previous 7 or 28 days. After standardising for age and sex, and adjusting for the number of interviews completed each month and the relative size of each UK country, the estimated rate of IID in the 7-day recall group was 1,530 cases per 1,000 person-years (95% CI: 1135-2113), while in the 28-day recall group it was 533 cases per 1,000 person-years (95% CI: 377-778). There was no significant variation in rates between the four countries. Rates in this study were also higher than in a related prospective study undertaken at the same time. CONCLUSIONS: The estimated burden of disease from IID varied dramatically depending on study design. Retrospective studies of IID give higher estimates of disease burden than prospective studies. Of retrospective studies longer recall periods give lower estimated rates than studies with short recall periods. Caution needs to be exercised when comparing studies of self-reported IID as small changes in study design or case definition can markedly affect estimated rates.

A novel mutation of the erythropoietin receptor gene associated with primary familial and congenital polycythaemia.

Primary familial and congenital polycythaemia (PFCP) is a rare form of inherited erythrocytosis caused by heterozygous mutations in the erythropoietin receptor gene (EPOR). We present a novel mutation in the EPOR in a 15-year-old male who was referred to our clinic for investigation of a persistently elevated haemoglobin level. A significant family history of unexplained erythrocytosis spanning four generations of the patient's family was established. The family history was also significant for an apparent increased rate of cerebrovascular disease in individuals with erythrocytosis. The mutation detected in our patient resides in exon 8 of EPOR, similar to all other EPOR mutations responsible for PFCP. These mutations result in truncation of the cytoplasmic domain of the receptor and impair down-regulation of signalling via the erythropoietin receptor (EPOR). Clinical manifestations in published cases have varied widely and there is a paucity of firm recommendations regarding the management of affected patients. Given the strong family history of complications attributable to erythrocytosis we have recommended venesection with a haematocrit target of ≤0.45 for our patient.

Evaluating the fitness of human lysozyme transgenic dairy goats: growth and reproductive traits.

While there are many reports in the literature describing the attributes of specific applications of transgenic animals for agriculture, there are relatively few studies focusing on the fitness of the transgenic animals themselves. This work was designed to gather information on genetically modified food animals to determine if the presence of a transgene can impact general animal production traits. More specifically, we used a line of transgenic dairy goats expressing human lysozyme in their mammary gland to evaluate the reproductive fitness and growth and development of these animals compared to their non-transgenic counterparts and the impact of consuming a transgenic food product, lysozyme-containing milk. In males, none of the parameters of semen quality, including semen volume and concentration, total sperm per ejaculate, sperm morphology, viability and motility, were significantly different between transgenic bucks and non-transgenic full-sib controls. Likewise, transgenic females of this line did not significantly differ in the reproductive traits of gestation length and litter size compared to their non-transgenic counterparts. To evaluate growth, transgenic and non-transgenic kid goats received colostrum and milk from either transgenic or non-transgenic does from birth until weaning. Neither the presence of the transgene nor the consumption of milk from transgenic animals significantly affected birth weight, weaning weight, overall gain and post-wean gain. These results indicate that the analyzed reproductive and growth traits were not regularly or substantially impacted by the presence or expression of the transgene. The evaluation of these general parameters is an important aspect of defining the safety of applying transgenic technology to animal agriculture.

Optimisation of intact cell MALDI method for fingerprinting of methicillin-resistant Staphylococcus aureus.

The use of matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) mass spectrometry on intact cell microorganisms, Intact Cell MALDI (ICM), has been shown by numerous workers to yield effective species level identification. Early work highlighted the significant effect that variation in culture media, incubation conditions and length of incubation had on the spectra produced. Therefore, in order to achieve reliable and reproducible species level identification and sub-typing of microorganisms from ICM fingerprints, it has been essential to develop standardised methods. For methicillin-resistant Staphylococcus aureus (MRSA), a major nosocomial pathogen, we have developed such a standardised method. In this paper we present the experimental parameters, namely, the incubation period, the number of passages required from lyophilised or stored isolates, the method of deposition of the bacterial cells, the concentration of matrix solution, the drying time of bacterial cells prior to the addition of the matrix solution, the time between preparation of the bacterial/matrix sample and analysis and the MALDI pulsed extraction setting, which were considered during the development of defined methods.

Fragmentation of N-linked glycans with a matrix-assisted laser desorption/ionization ion trap time-of-flight mass spectrometer.

N-Linked glycans were ionized from several matrices with a Shimadzu-Biotech AXIMA-QIT matrix-assisted laser desorption/ionization quadrupole ion trap time-of-flight mass spectrometer. [M+Na]+ ions were produced from all matrices and were accompanied by varying amounts of in-source fragmentation products. The least fragmentation was produced by 2,5-dihydroxybenzoic acid and the most by alpha-cyano-4-hydroxycinnamic acid and 6-aza-2-thiothymine. Sialic acid loss was extensive but could be prevented by formation of methyl esters. Fragmentation produced typical low-energy-type spectra dominated by ions formed by glycosidic cleavages. MS(n) spectra (n = 3 and 4) were used to probe the pathways leading to the major diagnostic ions. Thus, for example, an ion that was formed by loss of the core GlcNAc residues and the 3-antenna was confirmed as being formed by a B/Y rather than a C/Z mechanism. The proposed structures of several cross-ring cleavage ions were confirmed and it was shown that MS3 spectra could be obtained from as little as 10 fmol of glycan.