Do-it-yourself closed-loop systems for people living with type 1 diabetes.

Growing numbers of people with type 1 diabetes are using do-it-yourself closed-loop systems. While these technologies are not approved by regulatory bodies and are not commercially available, users of the technology report improvements in HbA1c and time in range, and reduced burden of diabetes. Healthcare professionals have expressed their concern that legal or regulatory body actions could ensue if they support people who choose to use do-it-yourself closed-loop systems. Diabetes UK's position statements make recommendations that aim to provide guidance for both people with diabetes and healthcare professionals, based on the current professional and legal situation. They respect an individual's right to make their own informed decisions about their diabetes management, and recommend that they should have access to the technology they need for optimal diabetes management. People who wish to use do-it-yourself closed-loop systems should continue to receive support and care from their diabetes team. Healthcare professionals should engage in conversations around do-it-yourself closed-loop systems, if the issue is raised, to allow a balanced discussion of risks and benefits. However, healthcare professionals cannot recommend the use of do-it-yourself closed-loop systems because of a lack of regulatory body approval and robust, published research to support safety or effectiveness. People using this technology should be aware that they do so at their own risk. This position statement recognizes that the development of diabetes technology is a rapidly changing environment, and guidance around do-it-yourself systems is required from professional and regulatory bodies.

Dynapenic Abdominal Obesity as a Risk Factor for Falls.

BACKGROUND: Obesity and low muscle strength (dynapenia) are independently associated with greater falls risk. It remains unclear whether dynapenia and obesity have an additive effect on falls risk, greater than either phenotype alone. OBJECTIVES: To determine whether a combination of abdominal obesity with dynapenia, dynapenic abdominal obesity (DAO), confers a greater risk of falls than either obesity or dynapenia alone in both men and women. DESIGN: An observational cohort study was conducted. SETTING AND PARTICIPANTS: Data from English adults (n=4239, 60-87 years) who took part in the English Longitudinal Study of Ageing were included. MEASUREMENTS: Dynapenia, was defined as hand-grip strength <20kg (female), <30kg (male). Abdominal obesity was defined as waist circumference >88cm (female), >102cm (male). Data on falls and fall-related injuries over a 2-year follow-up were collected. Multiple logistic regression analyses were performed adjusting for age and sex, with results expressed as odds ratios (OR) and areas under the receiver operating characteristic curve (AUC). RESULTS: Falls occurred in 1049 participants, with 284 reporting a related injury during follow-up. DAO was associated with greater OR of falls in men (OR 2.1, 95% Confidence Intervals (CI) 1.3-3.2). Dynapenia rather than obesity was associated with falls in women, with greatest OR observed in those with low hand-grip strength (OR 1.4, 95% CI 1.1-1.7). Individual discrimination was low for measures of obesity or dynapenia either alone or in combination (AUC 0.51-0.58). There was no relationship between fall-related injuries and obesity or dynapenia. CONCLUSION: Our findings suggest a synergistic effect of obesity with dynapenia on falls risk in men but not women.

Sequences of wool keratin proteins: the CSIRO connection.

Wool, a dead tissue of epithelial origin, derives many of its properties as a textile fibre from the structure and arrangement of the proteins from which it is comprised. Much of the progress in the elucidation of wool protein structures, as a step towards understanding this relationship between structure and properties, has been made in the Division of Protein Chemistry of Australia's Commonwealth Scientific and Industrial Research Organization.

Age-related changes in a spontaneously reassociating fraction of mouse DNA.

Rapidly reassociating fractions have been isolated from mouse brain and liver nuclear DNA by hydroxyapatite fractionation of sonicated and denatured preparations incubated at a Cot of 1. When prepared by thermal denaturation, a subfraction of this DNA, representing approximately 0.6% of liver and brain DNA, has been shown to spontaneously reassociate at Cot 10(-5). This fraction increases 3-fold in DNA from old animals. When prepared by alkaline denaturation or treated with pronase, no age-related increase is observed, suggesting the presence of an alkali-labile stabilizing protein component in DNA from old cells. A portion of this fraction is observed by electron microscopy under denaturing conditions to consists of looped hairpin structures in DNA from old, but not from yound or mature animals. These structures are not seen after pronase treatment.

Structural homology between hard alpha-keratin and the intermediate filament proteins desmin and vimentin.

Although it has been assumed that the microfibrils in hard -keratin are members of the class of structures known as intermediate filaments (IF), no firm chemical evidence relating the low-sulfur proteins in hard -keratin to other IF proteins has yet been published. We now present primary sequence data for two components from wool keratin which show striking similarities with two IF proteins, desmin and vimentin. The sequences show marked homology, a heptad repeat and a 9.5-residue periodicity in the linear disposition of the acidic and the basic residues. These data thus provide the first evidence that the low-sulfur proteins in hard -keratin and the other IF proteins do indeed have both a similar structure and a common evolutionary origin.

Specific antibody responses to Mycobacterium bovis in infected cattle analysed with six mycobacterial antigens in enzyme-linked immunosorbent assays.

A total of 23 (15.3 per cent) of 150 cattle infected with Mycobacterium bovis and which had never been tuberculin tested showed specific antibody responses to M bovis. Their sera may be important keys to the identification of unique M bovis antigens for use in specific serodiagnostic tests. Assessment of specific and non-specific responses was done by screening sera in six indirect anti-IgG enzyme-linked immunosorbent assays using whole cell sonicates of M bovis and five members of the Mycobacterium avium-intracellulare-scrofulaceum complex as respective antigens. Sera from 16 infected cattle that had been tuberculin tested positive and nine uninfected cattle (never tuberculin tested) were also assayed for specific and non-specific responses. Three other findings emerged. First, 43 of the 150 infected animals (28.7 per cent) showed no antibody responses to any of the mycobacterial antigens used. Secondly, the cattle showing the highest antibody levels were associated with the greatest cross reactivity. Lastly, the results indicated that tuberculin injections may increase antibody responses to shared, rather than specific, M bovis antigens in infected cattle.

Assessment of body fat and lean in the elderly by measuring body carbon and oxygen: validation against hydrodensitometry.

Based on the observation that the carbon-to-oxygen ratio (C/O) in tissue is a measure of fat content, we developed a model which correlates C/O to percent body fat. Carbon and oxygen mass and their ratio are measured in vivo by fast neutron inelastic scattering, using a miniature D-T neutron generator, at a radiation exposure of less than 0.06 mSv. We tested the validity of this model against hydrodensitometry with 19 healthy adult volunteers. The method was found to be accurate and insensitive to assumptions about the composition of lean tissue and, therefore, appropriate for studying the elderly and patients with catabolic conditions.

Ionophore toxicity in chickens: a review of pathology and diagnosis.

The ionophores (polyether compounds) have been the predominant means of chemical control of coccidiosis in the past 15 years because of the slow development of resistant strains to them relative to other anticoccidial drugs. However, the ionophores have a narrow range of safety, and it is sometimes difficult to ensure an even distribution of the drug throughout the feed. Diagnosis of toxicity is difficult because of the reversibility of clinical signs and the variability of pathological lesions ranging from none to non-specific. This paper reviews the known pathology of ionophore toxicity and the inadequacies of present diagnostic approaches. Analysis for ionophores in feed may be made by silica gel and high performance thin layer chromatography, but tissue analyses for toxic levels, a more specific diagnostic aid, are not commonly carried out. Limited studies suggest that residues in even severely intoxicated birds remain low. Diagnosis relies upon clinical signs of incoordination, leg weakness, diarrhoea and depression, non-specific histopathological lesions of myopathy and the presence of high levels of ionophores in the feed. If, however, toxicity is due to uneven distribution, feed samples may return false negative results. Current diagnostic criteria are, therefore, unsatisfactory and there is a clear need to investigate other diagnostic approaches.

Comparison of synexin isotypes in secretory and non-secretory tissues.

Three synexin isotypes were identified in bovine liver or adrenal medullary tissues by immune blotting of one- or two-dimensional SDS gels and by two-dimensional tryptic peptide mapping of gel bands or spots. These isotypes were: alpha-synexin, mass 47 kDa, pI 6.9; beta-synexin, mass 47 kDa, pI 6.5; and mu-synexin, mass 51 kDa, pI 6.1. A non-secretory tissue, bovine skeletal muscle, was found to contain only mu-synexin. The absence of alpha- and beta-synexins in a non-secretory tissue suggests these proteins may perform specific roles in the process of exocytosis.

Amino acid sequences of alpha-helical segments from S-carboxymethylkerateine-A. Tryptic and chymotryptic peptides from a type-II segment.

1. Amino acid-sequence studies were done on a peptide of mol.wt. approx. 12500 that was isolated from the highly helical fragments obtained by partial chymotryptic digestion of the low-sulphur proteins (S-carboxymethylkerateine-A) from wool. 2. The peptides obtained by tryptic and chymotryptic digestion of this large peptide were separated by ion-exchange chromatography on DEAE-cellulose at pH8.5 with an (NH4)(2)CO(3) concentration gradient and, where necessary, purified further by paper electrophoresis. 3. Determination of the sequences of many of these peptides showed that a high proportion of the cationic residues occurs in pairs. 4. Although two of the four S-carboxymethylcysteine residues are located in what appears to be a non-helical region near the N-terminus the other two S-carboxymethylcysteine residues occur in or near sequences suggesting a helical conformation. 5. Some peptides were obtained, in low yields, that appeared to be homologues of more major ones. These suggest either homologies in the helical portions of the low-sulphur proteins or the presence of closely related amino acid sequences in helical regions of completely different origins. 6. A partial sequence of the complete peptide is proposed.

The primary structure of component 8c-1, a subunit protein of intermediate filaments in wool keratin. Relationships with proteins from other intermediate filaments.

Component 8c-1, one of four highly homologous component-8 subunit proteins present in the microfibrils of wool, was isolated as its S-carboxymethyl derivative and its amino acid sequence was determined. Large peptides were isolated after cleaving the protein chemically or enzymically and the sequence of each was determined with an automatic Sequenator. The peptides were ordered by sequence overlaps and, in some instances, by homology with known sequences from other component-8 subunits. The C-terminal residues were identified by three procedures. Full details of the various procedures used have been deposited as Supplementary Publication SUP 50133 (4 pp.) at the British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1986) 233, 5. The result showed that the protein comprises 412 residues and has an Mr, including the N-terminal acetyl group, of 48,300. The sequence of residues 98-200 of component 8c-1 was found to correspond to the partial or complete sequences of four homologous type I helical segments previously isolated from helical fragments recovered from chymotryptic digests of microfibrillar proteins of wool [Crewther & Dowling (1971) Appl. Polym. Symp. 18, 1-20; Crewther, Gough, Inglis & McKern (1978) Text. Res. J. 48, 160-162; Gough, Inglis & Crewther (1978) Biochem. J. 173, 385]. Considered in relation to amino acid sequences of other intermediate-filament proteins, the sequence is in accord with the view that keratin filament proteins are of two types [Hanukoglu & Fuchs (1983) Cell (Cambridge, Mass.) 33, 915-924]. Filament proteins from non-keratinous tissues, such as desmin, vimentin, neurofilament proteins and the glial fibrillary acidic protein, which form monocomponent filaments, constitute a third type. It is suggested that as a whole the proteins from intermediate filaments be classed as filamentins, the three types at present identified forming subgroups of this class. The significant homologies between types I, II and III occur almost exclusively in segments of the chain that have been identified as having a coiled-coil structure together with the relatively short sections connecting these segments. The non-coiled-coil segments at the C- and N-termini show no significant homology between types, nor is homology in these segments apparent in all members of one type. Component 8c-1 does not show homology in its terminal segments with the known sequence of any other filamentin.(ABSTRACT TRUNCATED AT 400 WORDS)

Secondary structure of component 8c-1 of alpha-keratin. An analysis of the amino acid sequence.

The amino acid sequence of component 8c-1 from alpha-keratin was analysed by using secondary-structure prediction techniques, homology search methods, fast Fourier-transform techniques to detect regularities in the linear disposition of amino acids, interaction counts to assess possible modes of chain aggregation and assessment of hydrophilicity distribution. The analyses show the following. The molecule has two lengths of coiled-coil structure, each about 20 nm long, one from residues 56-202 with a discontinuity from about residue 91 to residue 101, and the other from residues 219-366 with discontinuities from about residue 238 to residue 245 and at about residue 306. The acidic and basic residues in the coiled-coil segment between residues 102 and 202 show a 9,4-residue structural period in their linear disposition, whereas between residues 246 and 366 a period of 9.9 residues is observed in the positioning of ionic residues. Acidic and basic residues are out of phase by 180 degrees. Similar repeats occur in corresponding regions of other intermediate-filament proteins. The overall mean values for the repeats are 9.55 residues in the N-terminal region and 9.85 residues in the C-terminal region. The regions at each end of the protein chain (residues 1-55 and 367-412) are not alpha-helical and contain many potential beta-bends. The regions specified in have a significant degree of homology mainly due to a semi-regular disposition of proline and half-cystine residues on a three-residue grid; this is especially apparent in the C-terminal segment, in which short (Pro-Cys-Xaa)n regions occur. The coiled-coil segments of component 8c-1 bear a striking similarity to corresponding segments of other intermediate-filament proteins as regards sequence homology, structural periodicity of ionic residues and secondary/tertiary-structure predictions. The assessments of the probabilities that these homologies occurred by chance indicate that there are two populations of keratin filament proteins. The non-coiled-coil regions at each end of the chain are less hydrophilic than the coiled-coil regions. Ionic interactions between the heptad regions of components 8c-1 and 7c from the microfibrils of alpha-keratin are optimized when a coiled-coil structure is formed with the heptad regions of the constituent chains both parallel and in register.

Determination of melting sequences in DNA and DNA-protein complexes by difference spectra.

A graphical formula is presented for determining the base ratio of melted DNA. By use of this formula, the composition of sequences which melt in different portions of the melting curves of Clostridium DNA, Escherichia coli DNA, and mouse DNA were determined. As the DNA melts, the per cent of adenine and thymine (AT) in the melted sequences decreases linearly with temperature. The average composition of sequences which melt in a given part of the melting curve is proportional to the base ratio of the DNA. The concentration and average composition of sequences were determined for three parts of the melting curves of the DNA samples, and a frequency distribution curve was constructed. The curve is symmetrical and has a maximum at about 56% AT. The distribution of GC-rich sequences on the E. coli chromosome was estimated by shearing, partially melting, and fractionating the DNA on hydroxylapatite. GC-rich sequences appear to occur every thousand base pairs, and have a maximum length of about 180 base pairs. The graphical formula was applied to the determination of the composition of sequences which melt in different parts of the melting curve of chromatin. Throughout the melting curve, the composition of the melting sequences is about 60% AT, which appears to suggest that relatively long sequences are melting simultaneously. Their melting temperature may be a function of the composition of the protein on different parts of the DNA. The problem of light scattering in DNA-protein and DNA was also investigated. A formula is presented which corrects for light scattering by relating the intensity of the scattered light to the rate of change of absorbance of DNA with wavelength.

Phosphatidylinositol-specific phospholipase C activity of chromaffin granule-binding proteins.

Using [U-14C]phosphatidylinositol as substrate, Ca2+-dependent phospholipase C activity was detected in a group of bovine adrenal medullary proteins that bind to chromaffin granule membranes in the presence of Ca2+ ("chromobindins," Creutz, C. E., Dowling, L. G., Sando, J. J., Villar-Palasi, C., Whipple, J. H., and Zaks, W. J. (1983) J. Biol. Chem. 258, 14664-14674). The activity was maximal at neutral pH and represented an 80- to 240-fold enrichment of adrenal medullary cytosol phospholipase C activity measured at pH 7.3. The stimulation of activity by Ca2+ was complex; no activity was present in the absence of Ca2+, 25% activation occurred at 1 microM Ca2+, and full activation at 5 mM Ca2+. The enzyme bound to chromaffin granule membranes in the presence of 2 mM Ca2+ but was released at 40 microM Ca2+, suggesting that intrinsic enzyme activity may be regulated by [Ca2+] at 1 microM, but additional activation at higher concentrations of Ca2+ is seen in vitro as a result of Ca2+-dependent binding of the active enzyme to substrate-containing membranes. This enzyme may generate diacylglycerol and phosphorylated inositol to act as intracellular messengers in the vicinity of the chromaffin granule membrane during the process of exocytosis.

Identification of methanotrophic lipid biomarkers in cold-seep mussel gills: chemical and isotopic analysis.

A lipid analysis of the tissues of a cold-seep mytilid mussel collected from the Louisiana slope of the Gulf of Mexico was used in conjunction with a compound-specific isotope analysis to demonstrate the presence of methanotrophic symbionts in the mussel gill tissue and to demonstrate the host's dependence on bacterially synthesized metabolic intermediates. The gill tissue contained large amounts of group-specific methanotrophic biomarkers, bacteriohopanoids, 4-methylsterols, lipopolysaccharide-associated hydroxy fatty acids, and type I-specific 16:1 fatty acid isomers with bond positions at delta 8, delta 10, and delta 11. Only small amounts of these compounds were detected in the mantle or other tissues of the host animal. A variety of cholesterol and 4-methylsterol isomers were identified as both free and steryl esters, and the sterol double bond positions suggested that the major bacterially derived gill sterol [11.0% 4 alpha-methyl-cholesta-8(14),24-dien-3 beta-ol] was converted to host cholesterol (64.2% of the gill sterol was cholest-5-en-3 beta-ol). The stable carbon isotope values for gill and mantle preparations were, respectively, -59.0 and -60.4% for total tissue, -60.6 and -62.4% for total lipids, -60.2 and-63.9% for phospholipid fatty acids, and -71.8 and 73.8% for sterols. These stable carbon isotope values revealed that the relative fractionation pattern was similar to the patterns obtained in pure culture experiments with methanotrophic bacteria (R.E. Summons, L.L. Jahnke, and Z. Roksandic, Geochim. Cosmochim. Acta 58: 2853-2863, 1994) further supporting the conversion of the bacteria methylsterol pool.