Topography and volume measurements of the optic nerve usingen-face optical coherence tomography

A special imaging instrument was developed which can acquire optical coherence tomography (OCT) en-face images from the eye fundus, and simultaneously a confocal image. Using this instrument we illustrate for the first time the application of en-face OCT imaging to produce topography and perform area and volume measurements of the optic nerve. The procedure is compared with the topography, area and volume measurements using a confocal scanning laser ophthalmoscope.

Technological advances in antigen delivery and synthetic peptide vaccine developmental strategies

Significant advances have been made in the field of peptide chemistry, especially in the design of synthetic peptide immunogens which has led to new concepts and strategies for human vaccine development. This article reviews some of these technological advances and approaches to vaccine design including the multiple antigenic peptide system, the lipid polylysine core peptide system, the polymerization of peptides into multivalent immunogens and self adjuvanting synthetic peptide-based immunogens.

Energy intake by multiple pass 24 h recall and total energy expenditure: a comparison in a representative sample of 3-4-year-olds

The accuracy of the multiple pass 24 h recall for assessment of habitual energy intake in pre-school children is unclear. The primary aim of this study was to assess its accuracy by comparison with measurement of total energy expenditure by doubly-labelled water in a representative sample of forty-one 3-4-year-olds. The recall method was well tolerated by subjects and was administered quickly and easily. However, it produced estimates of energy intake which significantly exceeded measures of total energy expenditure from doubly-labelled water, mean paired difference 660 kJ/d (P<0.01). Agreement between the two methods was poor at the individual level: limits of agreement 660+/-3018 kJ/d. Error and imprecision in both methods contribute to individual differences, but the present study suggests that the multiple pass 24 h recall does not provide accurate estimates of dietary energy intake in individual children.

Comparative genomics of Listeria species

Listeria monocytogenes is a food-borne pathogen with a high mortality rate that has also emerged as a paradigm for intracellular parasitism. We present and compare the genome sequences of L. monocytogenes (2,944,528 base pairs) and a nonpathogenic species, L. innocua (3,011,209 base pairs). We found a large number of predicted genes encoding surface and secreted proteins, transporters, and transcriptional regulators, consistent with the ability of both species to adapt to diverse environments. The presence of 270 L. monocytogenes and 149 L. innocua strain-specific genes (clustered in 100 and 63 islets, respectively) suggests that virulence in Listeria results from multiple gene acquisition and deletion events.

Accuracy of prediction of walking for young stroke patients by use of the FIM

BACKGROUND AND PURPOSE

Clinical prediction of walking outcome after a stroke is essential for effective discharge planning. However, its accuracy has hardly been explored. This study took place in a regional unit admitting patients with complex neurological disabilities for specialist inpatient rehabilitation. The aim was to compare predicted outcome (goal score) with achieved outcome (discharge score) on the seven-point locomotion subscale of the Functional Independence Measure (FIM), to evaluate its precision and identify factors influencing accuracy.

METHOD

Admission, goal and discharge scores were analysed retrospectively for 141 subjects (90 M; 51 F) admitted consecutively to the Unit with median age 54 years (range 15-68 years) with median length of stay 13.6 weeks (range 3-35 weeks).

RESULTS

Ninety subjects (64%) gained from two to six points; 50 subjects (35%) gained one point or showed no change. One patient deteriorated by two points. Excluding patients admitted with the highest score (FIM level 7), the overall level of agreement between predicted and discharge scores was moderate (weighted kappa 0.47). Prediction was accurate to +/- 1 point in 113 subjects (80%). Overprediction by > or = 2 points occurred in 16 subjects (11%) and underprediction by > or = 2 points in 12 subjects (9%). Analysis of the most-disabled cohort, admitted with FIM levels 1 or 2 scores, revealed a higher sensitivity for predicting 'independence' (FIM levels 5-7) (78%) than 'dependence' (FIM levels 1-4) (65%). Accuracy was not affected by age, gender or side of stroke. Inaccurate predictions were associated with lower admission FIM level scores (p = -0.26; p = 0.002) and a greater length of stay (p = 0.36; p < 0.001). Subjects with quadriplegia were more likely to have inaccurate outcome predictions made than those with hemiplegia (p = 0.025) and those with neglect were more likely to have inaccurate outcome predictions made than those without neglect (p = 0.017).

CONCLUSION

Further investigation into clinical prediction and the variables which confound accuracy is needed for effective planning.

The fasciated ear2 gene encodes a leucine-rich repeat receptor-like protein that regulates shoot meristem proliferation in maize

The ability to initiate organs throughout the lifecycle is a unique feature of plant development that is executed by groups of stem cells called meristems. The balance between stem cell proliferation and organ initiation is carefully regulated and ensures that organs can be initiated in regular geometric patterns. To understand how this regulation is achieved, we isolated a novel mutant of maize, fasciated ear2 (fea2), which causes a massive overproliferation of the ear inflorescence meristem and a more modest effect on floral meristem size and organ number. We cloned the fea2 gene using transposon tagging, and it encodes a membrane localized leucine-rich repeat receptor-like protein that is most closely related to CLAVATA2 from Arabidopsis. These findings provide evidence that the CLAVATA pathway for regulation of meristem size is functionally conserved throughout the angiosperms. A possible connection of fea2 to the control of crop yields is discussed.

Can brain-injured patients participate in an aerobic exercise programme during early inpatient rehabilitation?

OBJECTIVE

We investigated the capacity of brain-injured patients to participate in an aerobic exercise programme early after injury.

DESIGN

Retrospective analysis of exercise achievements in patients participating in a randomized controlled trial.

SETTING AND SUBJECTS

Ninety patients participated in an exercise training programme on a cycle ergometer at four inpatient neurological rehabilitation units for younger patients. At intake, impairments and function were rated on: Motricity Index, Ashworth Scale, Berg Balance Scale, Barthel Index and Functional Independence Measure.

INTERVENTIONS

Patients cycled for up to 30 minutes three times weekly for 24-36 sessions over 12 weeks.

MAIN OUTCOME MEASURES

Exercise performance was measured by: (a) number of sessions to achieve a cycling time of 30 minutes, (b) overall mean cycling time per session over 24 sessions and (c) mean time per session cycling at >60% of age predicted maximum heart rate (HR max) over 24 sessions.

RESULTS

Fifty-five patients completed 24 sessions. Thirty-five withdrew, largely for logistic reasons, before completing training; they were significantly less disabled than the 55 who remained. Forty-four of the 55 patients trained for an average of at least 20 minutes per session, 18 training at >60% HR max for this time. There were no differences in performance on the three exercise parameters between two groups of patients with baseline Barthel scores of < or = 12 and > or = 13.

CONCLUSIONS

Brain-injured patients with a range of disabilities have the capacity to participate in an exercise programme during early inpatient rehabilitation, though some may take longer to achieve adequate intensity of aerobic exercise.

The relationship between metformin therapy and the fasting plasma lactate in type 2 diabetes: The Fremantle Diabetes Study

AIMS

To determine (i) which factors, including metformin, are associated with the fasting plasma lactate concentration in type 2 diabetes, and (ii) whether plasma lactate is associated with haemodynamic and metabolic effects.

METHODS

We measured fasting plasma lactate in 272 well-characterized diabetic patients from a community-based sample, 181 (67%) of whom were taking metformin with or without other therapies. Linear regression analysis was used to identify predictors, including metformin therapy, of the plasma lactate, and to investigate associations between plasma lactate and resting pulse rate and serum bicarbonate. Factor analysis assessed independent relationships between groups of cosegregating variables.

RESULTS

Metformin-treated patients had higher plasma lactate concentrations than nonmetformin-treated subjects (geometric mean [s.d. range] 1.86 [1.34-2.59] vs 1.58 [1.09-2.30] mmol x l(-1), respectively; P < 0.001). In a linear regression model, plasma glucose, BMI and metformin use (but not dose) were independently associated with plasma lactate (P < or = 0.028); after adjustment for the former two variables, metformin-treated patients had a mean plasma lactate 0.16 mmol l-1 greater than in subjects not taking the drug. Factor analysis revealed that plasma lactate, plasma glucose, BMI and pulse rate cosegregated but serum bicarbonate was not in this grouping.

CONCLUSIONS

The present results show that metformin therapy increases the fasting plasma lactate in ambulant patients with type 2 diabetes from a community-based cohort. From associations in the data we hypothesize that this increase reflects (i) increased sympathetic activity in patients with the metabolic syndrome (ii) increased substrate (glucose) availability and (iii) a direct metformin effect.

Human RAD52 protein has extreme thermal stability

The human RAD52 protein plays an important role in the earliest stages of chromosomal double-strand break repair via the homologous recombination pathway. Individual subunits of RAD52 associate into seven-membered rings. These rings can form higher order complexes. RAD52 binds to DNA breaks, and recent studies suggest that the higher order self-association of the rings promotes DNA end joining. Monomers of the RAD52(1--192) deletion mutant also associate into ring structures but do not form higher order complexes. The thermal stability of wild-type and mutant RAD52 was studied by differential scanning calorimetry. Three thermal transitions (labeled A, B, and C) were observed with melting temperatures of 38.8, 73.1, and 115.2 degrees C. The RAD52(1--192) mutant had only two thermal transitions at 47.6 and 100.9 degrees C (labeled B and C). Transitions were labeled such that transition C corresponds to complete unfolding of the protein. The effect of temperature and protein concentration on RAD52 self-association was analyzed by dynamic light scattering. From these data a four-state hypothetical model was developed to explain the thermal denaturation profile of wild-type RAD52. The three thermal transitions in this model were assigned as follows. Transition A was attributed to the disruption of higher order assemblies of RAD52 rings, transition B to the disruption of rings to individual subunits, and transition C to complete unfolding. The ring-shaped quaternary structure of RAD52 and the formation of higher ordered complexes of rings appear to contribute to the extreme stability of RAD52. Higher ordered complexes of rings are stable at physiological temperatures in vitro.

Involvement of pallidothalamic circuitry in working memory

This study evaluated the capacity of mu-opioid and glutamate receptor agonists to differentially regulate the involvement of the GABAergic projection from the ventral pallidum to the mediodorsal thalamus in working memory and locomotor activity. Microinjection of either the ionotropic glutamate receptor agonist alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) or the mu agonist [D-Ala(2),N-Me-Phe(4),Gly-ol(5)]enkephalin into the ventral pallidum of male Sprague-Dawley rats produced a dose-dependent impairment in working memory, estimated using a forced delayed alternation task in a T-maze. Performance in a spatial discrimination task without delay was also impaired by glutamate, but not by mu receptor, stimulation. Involvement of the GABAergic projection from the ventral pallidum to the mediodorsal thalamus in mu-opioid-induced impairment of working memory was verified by showing that inhibiting GABA(B) receptors in the mediodorsal thalamus blocked the effect of [D-Ala(2),N-Me-Phe(4),Gly-ol(5)]enkephalin in the ventral pallidum. Similarly, either glutamate or mu-opioid receptor stimulation in the ventral pallidum elicited motor activity, and the motor stimulant effect of the mu agonist was blocked, while that of AMPA is not affected by GABA(B) receptor blockade in the mediodorsal thalamus. Distinction between mu and glutamate receptor stimulation was further revealed by the fact that stimulating mu receptors in the ventral pallidum caused a dose-dependent reduction in extracellular GABA levels, while AMPA was without effect on GABA in the ventral pallidum. These data indicate that stimulating mu-opioid receptors reduces GABAergic tone in the ventral pallidum, which increases activity in the GABAergic projection to the mediodorsal thalamus, thereby impairing working memory. Moreover, it is hypothesized that mu receptors in the ventral pallidum gate the recruitment of working memory into ongoing behavioral activity.

Total energy expenditure in children with obstructive sleep apnoea syndrome

Childhood obstructive sleep apnoea syndrome (OSAS) acts as a check on growth and nutritional status. An increase in sleeping energy expenditure has been proposed as a possible mechanism, but to date, no studies have determined whether energy requirements (total energy expenditure; TEE) are raised in OSAS. The aim of this study was to test the hypothesis that OSAS is associated with increased TEE. Eleven children (mean+/-SD 5.8+/-2.2 yrs of age) with OSAS confirmed by nocturnal polysomnography were each matched with a pair of healthy controls (n=22) of the same age and sex. TEE was measured using the doubly-labelled water method in all subjects. In 10/11 patients TEE was also measured after adenotonsillectomy and changes in TEE assessed. There was no significant difference in TEE between patients (mean+/-SD 325+/-44 kJ x kg(-1) x day(-1)) and controls (339+/-48 kJ x kg(-1) x day(-1)), nor between patients and age- and sex-specific literature data on TEE, using the doubly-labelled water method. Differences in TEE within patients, before versus after surgery, were minor and not statistically significant. This study does not support the hypothesis that obstructive sleep apnoea syndrome in childhood is associated with increased energy requirements, and suggests that alternative explanations for the effect of this syndrome on growth and energy balance should be sought.

Human RAD52 exhibits two modes of self-association

The human RAD52 protein plays an important role in the earliest stages of chromosomal double-strand break repair via the homologous recombination pathway. Individual subunits of RAD52 self-associate into rings that can then form higher order complexes. RAD52 binds to double-strand DNA ends, and recent studies suggest that the higher order self-association of the rings promotes DNA end-joining. Earlier studies defined the self-association domain of RAD52 to a unique region in the N-terminal half of the protein. Here we show that there are in fact two experimentally separable self-association domains in RAD52. The N-terminal self-association domain mediates the assembly of monomers into rings, and the previously unidentified domain in the C-terminal half of the protein mediates higher order self-association of the rings.

Clinical nurses as teachers: insights from students of nursing in their first semester of study

This paper reports the findings of a study which sought to gain insights about the role of clinical nursing staff in the planned clinical experience of undergraduate nursing students. This study differs from others in that the perspectives of students of nursing in their first year of the undergraduate programme are sought, and the role of clinical nurses rather than clinical teachers is of particular interest. Using a story-telling approach, an exploration of students' perspectives on the role of clinical nursing staff in their clinical learning was undertaken. Analysis allowed findings to be grouped into helpful and unhelpful behaviours, Helpful behaviours included understanding and being friendly, showing interest and explaining. Behaviours that students found unhelpful to their learning were often passive rather than active, but they made students feel acutely aware of being unwelcome in the clinical area. Several students described feeling intrusive, uncomfortable and even unwelcome in clinical areas because o the attitudes and behaviour of clinicians. Findings of this study highlight the importance of clinicians and academic nurses working together to ensure that students of nursing, who represent the future of the profession, are provided with the best possible opportunities for clinical learning.

Toxicologic lesions associated with two related inhibitors of oxidosqualene cyclase in the dog and mouse

Two novel hypolipidaemic agents, both members of the aminopyrimidine series, with a mode of action of inhibition of oxidosqualene cyclase (OSC), were administered orally to dogs and mice for 14 and 28 days. Both compounds produced a similar spectrum of pathologic changes. In dogs, the agents produced equatorial single cell necrosis and cataract in the lens (also observed clinically); atrophy, ulceration, and inflammation of the cornea; hyperkeratosis, acanthosis, hair papillary atrophy, and inflammation of the skin; and epithelial degeneration and sperm granuloma in the epididymides. One female dog showed signs of liver toxicity. In mice, severe cataract formation was seen with both compounds, and liver toxicity was produced by one of the compounds. The severity and speed of onset of the cataract formation were very marked. The changes seen were dissimilar to those reported with the most commonly used class of hypolipidaemic agents in the clinic, the hydroxymethyl glutaryl coenzyme A (HMGCoA) reductase inhibitors but were reminiscent of those reported for the hypolipidaemic agent Triparanol. which was predictive of toxicity seen in man.

Fibroblast growth factor signalling and cyclin D1 function are necessary for normal mammary gland development during pregnancy. A transgenic mouse approach

A number of growth factors, growth factor receptors and cell cycle regulatory proteins have been implicated in the genesis of mammary carcinomas both in animal models as well as in human breast tumour samples. Studies on the development of the mammary gland has revealed that several of the proto-oncogenes, or their closely related gene-family members, have a function in the normal growth and differentiation of the gland. In this review the role of fibroblast growth factor signalling and the critical requirement for the cell cycle regulator, cyclin D1 is discussed with respect to their normal function in mammary gland development and abnormal role in mammary carcinogenesis.

A dynamic compartmental food chain model of radiocaesium transfer to Apodemus sylvaticus in woodland ecosystems

A study was undertaken to quantify the activity concentrations of 137Cs in Apodemus sylvaticus (the woodmouse) in two woodland sites, Lady Wood and Longrigg Wood, adjacent to British Nuclear Fuels Ltd. (BNFL) Sellafield, Cumbria, UK. A deterministic dynamic compartmental food chain model was also constructed to predict 137Cs activity concentration [Bq kg(-1) dry weight (dw)] in A. sylvaticus on a seasonal basis given the activity concentrations in its diet. Within the coniferous woodland site (Lady Wood), significant differences were found between seasons (P < 0.05, summer vs. autumn cohort; P < 0.001, spring vs. autumn cohort), with an autumn peak in activity concentration (geometric mean = 140 x/divided by 2.3 Bq kg(-1) dw) being attributed to mycophagy. Fungal concentrations ranged from 2-3213 Bq kg(-1) dw. The modelled activity concentrations fell between the confidence intervals of the observed data in four of the six seasonal cohorts sampled. Disparities between predicted and observed activity concentrations are attributed to uncertainties surrounding the fundamental feeding ecology of small mammals.

Interprofessional working and learning in a UK operating department

This study explores the issues of working and training together for nurses and operating department assistants and practitioners (ODAs/ODPs), based on experiences in an operating department. Interviews and focus groups with nurses, ODAs/ODPs and medical staff were the means of collecting data.

Alpha-emitting 'hot particles' in the vicinity of BNFL Sellafield, Cumbria

In a survey of environmental samples in the vicinity of BNFL Sellafield, two alpha-emitting radioactive particles were found in samples of grass. One particle appears to be of mineral origin, the other was not definitively identified, but may be a fragment of fuel cladding. Conservative estimates of the activities of these particles are very low. The abundance of radioactive particles in the terrestrial food chain appears to be low, with no evidence for any alpha-emitting hot particles in foodstuffs for consumption by humans. Results suggest that there is no significant dose to man through inhalation or ingestion pathways.