Agreement between the Takeda UA-731 automatic blood pressure measuring device and the manual mercury sphygmomanometer: an assessment under field conditions in Newcastle upon Tyne, UK.

Study Objective: To assess agreement between two Takeda UA-731 automatic blood pressure measuring devices (referred to as machines A and B) and two manual mercury sphygmomanometers.

Design: A 'Y' connector attached each Takeda UA-731 to a manual mercury sphygmomanometer. Simultaneous measurements were made on adult subjects.

Cycle helmets--when is legislation justified?

The issue of mandatory cycle helmets is highly contentious. The aim of this paper is not to argue for or against legislation but to suggest criteria on which the debate should focus. This is done by attempting to answer the question: 'What criteria must be met before cycle helmet wearing is enforced?' Consideration is given to principles, precedents and consequences and four criteria are suggested.

Outlook for survivors of childhood in sub-Saharan Africa: adult mortality in Tanzania. Adult Morbidity and Mortality Project.

Objective: To measure age and sex specific mortality in adults (15-59 years) in one urban and two rural areas of Tanzania.

Design: Reporting of all deaths occurring between 1 June 1992 and 31 May 1995.

Setting: Eight branches in Dar es Salaam (Tanzania's largest city), 59 villages in Morogoro rural district (a poor rural area), and 47 villages in Hai district (a more prosperous rural area).

The relationships between cardiovascular risk factors and socio-economic status in people with diabetes.

The hypothesis that the prevalence of cardiovascular risk factors in people with diabetes is inversely related to socio-economic status was tested. Demographic and biochemical data were collected on 1246 patients, aged 20-69 years, attending a hospital diabetes clinic. This is estimated to represent between 71% and 78% of all people of this age with a diagnosis of diabetes in the health authority.

Three-dimensional location of the main immunogenic region of the acetylcholine receptor.

About two-thirds of the antibodies to the nicotinic acetylcholine (ACh) receptor in patients with the autoimmune disease myasthenia gravis bind to the main immunogenic region (MIR). This is small, well-defined region on each of the two alpha subunits, containing residues 67-76 (alpha 67-76). By determining the structure of the ACh receptor complexed with two different fragments of an MIR-directed antibody, we have determined the three-dimensional location of the MIR (and therefore residues alpha 67-76) to be at the extreme synaptic end of each alpha subunit.

Acetylcholine receptor channel imaged in the open state.

The structure of the open-channel form of the acetylcholine receptor has been determined from electron images of Torpedo ray postsynaptic membranes activated by brief (< 5 ms) mixing with droplets containing acetylcholine. Comparison with the closed-channel form shows that acetylcholine initiates small rotations of the subunits in the extracellular domain, which trigger a change in configuration of alpha-helices lining the membrane-spanning pore. The open pore tapers towards the intracellular membrane face, where it is shaped by a 'barrel' of alpha-helices having a pronounced right-handed twist.

Promoting the public health benefits of cycling.

The potential health gain from increased levels of cycling in Britain is large. This paper reviews current levels of bicycle ownership and use, and the factors which influence whether or not people choose to cycle in Britain. Cycle ownership is strongly associated with affluence and children.

Analysis of transient structures by cryo-microscopy combined with rapid mixing of spray droplets.

A simple method to determine transient conformations of biological molecules is described. The two reactants (e.g.

Images of purified Shaker potassium channels.

Background: Voltage-gated K+ channels play an important role in the control of neuronal excitability and synaptic plasticity. Their low abundance and extraordinary heterogeneity have rendered their purification from natural sources difficult. We have previously cloned a voltage-gated K(+)-channel gene, Shaker, from Drosophila.

Nicotinic acetylcholine receptor at 9 A resolution.

The nicotinic acetylcholine receptor is a cation-selective, ligand-gated ion channel, involved in signal transmission at the chemical synapse. This paper reports the three-dimensional appearance of the channel in the closed conformation, at 9 A resolution. The structure was determined by electron microscopy of tubular crystals of Torpedo postsynaptic membranes embedded in amorphous ice.

Role of GTP hydrolysis in microtubule dynamics: information from a slowly hydrolyzable analogue, GMPCPP.

The role of GTP hydrolysis in microtubule dynamics has been reinvestigated using an analogue of GTP, guanylyl-(alpha, beta)-methylene-diphosphonate (GMPCPP). This analogue binds to the tubulin exchangeable nucleotide binding site (E-site) with an affinity four to eightfold lower than GTP and promotes the polymerization of normal microtubules. The polymerization rate of microtubules with GMPCPP-tubulin is very similar to that of GTP-tubulin.

New acuity test for toddlers.

Preferential looking is the technique of choice for measuring visual acuity in infants and young children. Most workers agree that the toddler age group, 1 to 3 years, is the most difficult to test. This is because of their short attention span and restlessness, but mostly because they find the grating target used in the test, frankly boring.

Structure of gap junction channels.

Gap junctions are regions of contact between adjacent cells, consisting of arrays of channels linking the cell interiors. The channels are formed by polypeptides called connexins; the amino acid sequences of many different connexins are known, and they are thought to resemble each other closely in tertiary and quarternary structure. Single channels have recently been isolated and purified, and earlier evidence has been confirmed showing that they consist of six identical subunits arranged around the central pore.

Isolation and purification of gap junction channels.

This paper reports methods we have developed to solubilize gap junction channels, or connexons, from isolated gap junctions and to purify them in milligram quantities. Two sources of material are used: rat liver gap junctions and gap junctions produced by infecting insect cells with a baculovirus containing the cDNA for human liver beta 1 protein (connexin 32). Complete solubilization is obtained with long chain detergents (lauryl dimethyl amineoxide, dodecyl maltoside) and requires high ionic strength and high pH as well as reducing conditions.

Three-dimensional structure of the acetylcholine receptor by cryoelectron microscopy and helical image reconstruction.

Long tubular vesicles have been grown from isolated Torpedo postsynaptic membranes, in which the receptors are arranged helically on the vesicle surface. The structures of these tubes have been analyzed by cryoelectron microscopy of specimens embedded in thin films of ice, combined with helical image reconstruction. Complete data sets from tubes belonging to several helical families have been obtained to a resolution of 17 A in all directions.

Ion channel of acetylcholine receptor reconstructed from images of postsynaptic membranes.

The nicotinic acetylcholine receptor belongs to a class of molecules that respond transiently to chemical stimuli by opening a water-filled channel through the cell membrane for cations to diffuse. This channel lies along the central axis delineated by a ring of five homologous, membrane-spanning subunits and thus has properties, such as conductance and ion selectivity, which depend on the profile created by the encircling subunits. Insight has been gained recently about the amino-acid residues implicated directly in the ion transport, and some information about the subunit configuration around the channel has come from electron microscopy studies of postsynaptic membranes crystallized in the form of flattened tubular vesicles.