Investigation of an outbreak of vomiting in nurseries in South East England, May 2012.

On 30 May 2012, Surrey and Sussex Health Protection Unit was called by five nurseries reporting children and staff with sudden onset vomiting approximately an hour after finishing their lunch that day. Over the following 24 h 50 further nurseries supplied by the same company reported cases of vomiting (182 children, 18 staff affected). Epidemiological investigations were undertaken in order to identify the cause of the outbreak and prevent further cases. Investigations demonstrated a nursery-level attack rate of 55 out of 87 nurseries (63·2%, 95% confidence interval 52·2-73·3). Microbiological tests confirmed the presence of Bacillus cereus in food and environmental samples from the catering company and one nursery. This was considered microbiologically and epidemiologically consistent with toxin from this bacterium causing the outbreak. Laboratory investigations showed that the conditions used by the caterer for soaking of pearl haricot beans (known as navy bean in the USA) used in one of the foods supplied to the nurseries prior to cooking, was likely to have provided sufficient growth and toxin production of B. cereus to cause illness. This large outbreak demonstrates the need for careful temperature control in food preparation.

Genome sequence analysis of Ebola virus in clinical samples from three British healthcare workers, August 2014 to March 2015.

We determined complete viral genome sequences from three British healthcare workers infected with Ebola virus (EBOV) in Sierra Leone, directly from clinical samples. These sequences closely resemble those previously observed in the current Ebola virus disease outbreak in West Africa, with glycoprotein and polymerase genes showing the most sequence variation. Our data indicate that current PCR diagnostic assays remain suitable for detection of EBOV in this epidemic and provide confidence for their continued use in diagnosis.

Identification of six Listeria species by real-time PCR assay.

UNLABELLED: The Listeria genus comprises 10 recognized species. Listeria monocytogenes causes listeriosis in humans and other animals primarily via contaminated food or animal feed. Listeria ivanovii causes listeriosis in animals and on rare occasions in humans. The identification of nonpathogenic species of Listeria in foods indicates that conditions exist that support the growth of pathogenic strains and is used to facilitate the implementation of control and prevention measures. This study shows the development and evaluation of a 5'exonuclease real-time PCR assay for the rapid identification of Listeria seeligeri, Listeria welshimeri, L. monocytogenes, L. ivanovii, Listeria grayi and Listeria innocua. The assay consists of two triplexes that were evaluated using 53 cultures of Gram-positive bacteria, including 49 Listeria spp. from human, animal, food or food-processing environments. The assay was rapid, specific and reproducible and could identify each of the six species from a mixture of strains. The developed assay proved to be a powerful means of rapidly identifying Listeria species and could be usefully implemented in busy specialist reference laboratories. SIGNIFICANCE AND IMPACT OF THE STUDY: The identification of species of Listeria from foods is important to monitor pathogenic strains and facilitates the implementation of control measures. This study shows the development and evaluation of a 5'exonuclease real-time PCR assay for the rapid identification of L. seeligeri, L. welshimeri, L. monocytogenes and L. ivanovii, L. grayi, L. innocua. The developed assay proved to be specific, rapid and reproducible and therefore could be implemented in busy specialist reference laboratories.

An acute inpatient geriatric assessment and treatment unit.

The inpatient geriatric assessment unit (GAU) is an important component of the Geriatric Assessment and Treatment Centre (GATC) at the Royal Jubilee Hospital in Victoria, British Columbia. The Centre attempts to accomplish the following: to provide, at the request of the attending physician, diagnostic, treatment, and management services where it best suits the patient (ie, at home, in the outpatient service, or following admission to the ward); and to provide, if necessary, follow-up service after discharge to help prevent readmission to the acute hospital or any part of the geriatric service.

A "convertible pore" model of neural membrane conductance.

Instead of the single-channel pore proposed earlier [Wooldridge, D. E. (1984) Proc. Natl. Acad. Sci. USA 81, 5609-5612] for the transit of conductance ions through the neural membrane, a pore with a second channel for "influence ions" of calcium or magnesium is considered in this paper. By entering trapping centers at the closed inner ends of the new channels, the influence ions are postulated to alter the rates of chemical reactions that change the configurational state of the gates guarding the inner ends of the nearby conductance channels. This makes the permeability of the conductance channels strongly dependent on voltage. Using a four-state reaction scheme for both the sodium and potassium pore systems, a computer model of the membrane conductance is constructed. When suitable values are assigned to its parameters, the model closely reproduces the results of the Hodgkin-Huxley voltage-clamp and action potential experiments.

Movement of ions through fixed pores in the neural membrane.

A simple configuration is first proposed for the pores used by sodium and potassium ions in moving through the neural membrane. The voltage dependence of the ion current through a system of such pores is then derived from diffusion theory and shown not to agree well with experimental observation. Good agreement is obtained, however, when the end segments of the pores are modified to include constrictions and ion-specific trapping centers.

Endotracheal granular cell myoblastoma. A failure of laser therapy.

A patient had multicentric endobronchial granular cell myoblastoma. Progression with worsening tracheal obstruction following carbon dioxide laser therapy led to surgical resection. Flow volume loops documented progressive relief of airway obstruction after laser and resectional surgery. Our experience with failure of laser therapy supports previous recommendations for surgical therapy for large (greater than 8 mm) lesions of the trachea.

Memory neuron: synapse microchemistry for the memory component of a neuroconnective brain model.

This paper examines the synaptic microchemistry required if a memory neuron is to have the operating characteristics previously attributed to it [Wooldridge, D.E. (1980) Proc. Natl. Acad. Sci. USA, 77,2305-2308]. It is concluded that the requirements can be met by a combination of membrane mechanisms not very different from those that are commonly postulated to explain the properties of known types of neurons.

Memory neuron: operating characteristics for the memory component of a neuroconnective brain model.

In this paper an attempt is made to deduce the principal operating operating characteristics that a neuron would need in order to qualify as the basic memory component of a sensory memory system. The required characteristics are found to include the possession of many--perhaps more than 100--separately innervated "recording connections," in each of which the constituent synapses can be put in a persisting state of (inhibitory) effectiveness or of ineffectiveness depending on whether the input axon is inactive or is carrying spikes at the time a triggering "recording command" comes to the memory neuron. The synapses of the recording connections must also respond to an "erasing command" by assuming a common prerecording state unaffected by previous history. At other times a synapse-regeneration feature must operate, to counter any decay of effectiveness of connections that have been left by recording in an effective state as well as any acquisition of effectiveness by connections that have been left in an ineffective state.

The geriatric institution as a therapeutic modality.

Geriatric centres complete with day-hospital facilities are essential for good care of the elderly. Institutions for the ill elderly should be upgraded to provide these people with the full range of services required as their diseases wax and wane. Within this community the resident could move as his needs altered, from minimal support in lodge-style accomodation, to continual "heavy" nursing in a hospital setting providing long-term care. Such a concept accepts that, in the elderly, as they age, new diseases develop that are often difficult to diagnose, and that they require diagnostic and therapeutic services of much greater range than is presently considered adequate in most institutions providing long-term care.

Spike-forming model of the neural membrane: improvement in the parameter values.

A new set of values is presented for the reaction rate and ionic conductance parameters that determine the properties of the previously developed model of the neural membrane [Wooldridge, D.E. (1975) Proc. Natl. Acad. Sci. USA 72, 3468-3471]. The resulting improvement in the extent of the agreement between theory and experiment is briefly described.

Spike-forming model of neural membrane: computer simulation of additional perfused axon experiments.

In this paper a physical model of the neural membrane that I developed is tested for its ability to account for the details of the action potential spikes observed in squid giant axons, when perfused with sodium- and potassium-free fluids and surrounded by a calcium chloride solution. The near-zero resting potential of these perfused axons is accounted for by the model. The sizes, shapes, and conductances of the spikes observed with a number of different perfusates are also accounted for, when suitable values are assigned to the so-far unmeasured membrane constants that control the model properties. The three papers comprising the series are summarized at the end of this paper.

Spike-forming model of the neural membrane: computer simulation of some perfused axon experiments.

This paper is an attempt to account for the action potential spikes observed when the normal axoplasm of a squid giant neuron is replaced by a postassium-free, sodium-rich fluid, and the axon is immersed in a potassiumand sodium-free, calcium-rich bath. For this purpose a recently described model of the neural membrane [Wooldridge, D. E. (1975) Proc. Nat. Acad. Sci. USA 72, 3468-3471] is extended. Allowances are made for the flow of Ca++, Cl-, and Na+ ions through some of the membrane pore configurations, as well as for some electron conductance, all of amounts too small to be significant in the normal neuron. It is also postulated that the nature of the perfusing fluid affects the rates of some of the reactions that change the convertible gates from one configuration to another, as well as the ionic permeabilities of the resulting configurations. The result of the modifications is a single membrane model that accounts for the 3-sec, 15 muA/cm2 action potential spikes of the perfused axon as well as for the 0.5-msec, 1 mA/cm2 spikes of the normal neuron.

A spike-forming model of the neural membrane.

A model of the neural membrane is described, based on a set of "convertible gates" on its inner surface. The atomic arrangement of a gate is specified to be subject to modification by a set of chemical reactions, sometimes permitting sodium ions, sometimes potassium ions, sometimes neither, to have access to the transmembrane channel it guards. Reaction rate and current/voltage equations are developed, values assigned to the parameters, and computer solutions obtained. Under pulse or continuous stimulating current the model is found to generate action potential spikes closely similar in height and shape to those of real neurons. Other electrical properties are also relatively neuron-like.