Amplitude and phase relations of electrocortical waves regulated by transhypothalamic dopaminergic neurones: A test for a linear theory

We have previously proposed that electrocortical activity (EEG) arises as a manifestation of linear waves generated by resonance among telencephalic neurones, and that this activity is controlled in part by ascending neurones from the brain-steim, which regulate the damping of each resonance. The presentexperiments focus on a specific class of ascending neurones, the mesotelencephalic dopaminergic cells, because these cells are thought to mediate important psychological effects, and are conveniently subject to selective lesion. A critical test of the theory is undertaken, by performing selective unilateral lesion, assessing the changes in the power spectrum of the EEG attributable to lesion, and determining whether the changes in phase of the EEG correspond to that predicted from the changes in power. Results support the theory, although the model order applicable in these experiments is inadequate. The consequences of these findings for automata theory, linear network theory and their application to mammalian brains are briefly discussed.     

Cyclin dependent kinase regulation

Cyclin-dependent kinases (CDKs) are key regulators of the cell cycle and their activities are consequently tightly regulated. Recent developments in the field of CDK regulation have included the discovery and characterization of CDK inhibitors. These developments have had an impact on our understanding of how other signalling pathways may be linked to the cell cycle machinery.     

Quantitative studies of modern wet-ground molluscan faunas from Bossington, Hampshire

There have been few quantitative studies of modern Mollusca in Britain, especially from wet-ground areas. This is particularly true of the English chalklands, which is surprising given the focus of sub-fossil molluscan research in that area. Those studies that are available highlight the difficulty of separating molluscan faunas from structurally complex habitats such as fen and carr. Quantitative molluscan data from a variety of wet-ground habitats situated within the chalklands of southern England were analysed using an indirect ordination technique, Principal Components Analysis. This demonstrated that the separation of faunas from structurally complex wet-ground habitats is possible. The numerical separation does not rely on indicator species, but is a function of variation of the predominant species. It is suggested that further studies of this type might aid the interpretation of sub-fossil Mollusca from wet-ground contexts.     

Linear epitopes of colonization factor antigen I and peptide vaccine approach to enterotoxigenic Escherichia coli

Enterotoxigenic Escherichia coli (ETEC) cause diarrhea in infants and in travelers to developing countries. The bacteria utilize colonization factors (CF) for adherence to intestinal epithelia, then release toxins causing diarrhea. CF are strong immunogens as well as protective antigens. While 20 ETEC CF have been described in the literature, 11 CF are prominent enough to be considered for vaccine targeting. Of this group, six of the members fall into the CFA/I family of CF. Geysen pin (peptide) linear epitope analysis demonstrated that three regions containing linear epitopes exist in CFA/I, and that both B- and T-cell linear epitopes of CFA/I were concentrated at the N-terminus of the protein. We have determined N-terminal sequence of the CFA/I family members not previously sequenced. Comparison of the protein sequence of the six members of the family showed a strong homology up to residue 36. A peptide of 36 amino acids representing a consensus of the six sequences was synthesized and used to immunize animals. The antibody induced to the peptide was reactive to the peptide as well as cross-reactive to each member of the CFA/I family in Western blots. In addition, this antibody agglutinated three of the six members of the CFA/I family when added to whole cells expressing the native CF. We are currently evaluating different carriers and conjugation methods to maximize production of high titer, agglutinating antibody. It is hoped that this and related research will result in an effective and inexpensive cross-reactive and cross-protective ETEC vaccine. Received 04 October 1996/ Accepted in revised form 14 April 1997     

A multicentre observational study of presentation and early assessment of acute stroke

ObjectiveTo investigate delays in the presentation to hospital and evaluation of patients with suspected stroke.DesignMulticentre prospective observational study.Setting22 hospitals in the United Kingdom and Dublin.Participants739 patients with suspected stroke presenting to hospital.ResultsThe median age of patients was 75 years, and 400 were women. The median delay between onset of symptoms and arrival at hospital was 6 hours (interquartile range 1 hour 48 minutes to 19 hours 12 minutes). 37% of patients arrived within 3 hours, 50% within 6 hours. The median delay for patients using the emergency service was 2 hours 3 minutes (47 minutes to 7 hours 12 minutes) compared with 7 hours 12 minutes (2 hours 5 minutes to 20 hours 37 minutes) for referrals from general practitioners (P<0.0001). Use of emergency services reduced delays to hospital (odds ratio 0.45, 95% confidence interval 0.23 to 0.61). The median time to evaluation by a senior doctor was 1 hour 9 minutes (interquartile range 33 minutes to 1 hour 50 minutes) but was undertaken in only 477 (65%) patients within 3 hours of arrival. This was not influenced by age, sex, time of presentation, mode of referral, hospital type, or the presence of a stroke unit. Computed tomography was requested within 3 hours of arrival in 166 (22%) patients but undertaken in only 60 (8%).ConclusionDelays in patients arriving at hospital with suspected stroke can be reduced by the increased use of emergency services. Over a third of patients arrive at hospital within three hours of stroke; their management can be improved by expediting medical evaluation and performing computed tomography early.

What is already known on this topic

Delay in presentation and assessment of patients with suspected stroke prevents the possible benefits from thrombolysis being achievedLittle is known about the presentation and early management of patients with acute stroke in the United Kingdom

What this study adds

Most patients with suspected stroke in the United Kingdom arrive at hospital within six hours of the onset of symptomsNot all patients are evaluated by a senior doctor within three hours of arrival at hospital and most do not undergo computed tomographyThe potential for thrombolysis in patients with acute stroke can be improved significantly by greater use of emergency services and expediting evaluation and investigations by doctors