Measurement of the transverse electric field profile of light by a self-referencing method with direct phase determination

We present a method for measuring the transverse electric field profile of a beam of light which allows for direct phase retrieval. The measured values correspond, within a normalization constant, to the real and imaginary parts of the electric field in a plane normal to the direction of propagation. This technique represents a self-referencing method for probing the wavefront characteristics of light.

The feasibility and acceptability of muscle biopsy in epidemiological studies: findings from the Hertfordshire Sarcopenia Study (HSS)

BACKGROUND

Sarcopenia, the loss of muscle mass and strength, is associated adversely with disability, morbidity and mortality. Epidemiological findings suggest influences operating across the life course may be important. Our aim was to ascertain the feasibility and acceptability of obtaining muscle tissue from healthy older people in order to ultimately identify cellular mechanisms underlying life course influences on sarcopenia.

METHODS

105 men with documented birth weight consented to detailed assessment of muscle mass and strength, and a biopsy of the vastus lateralis using the Weil-Blakesley conchotome. Acceptability was ascertained by questionnaire and a 100 mm pain Visual Analogue Scale (VAS). 100 mm indicated severe pain.

RESULTS

Muscle biopsy was successfully carried out in 102 out of 105 participants, mean yield 107 mg (range 20-290 mg). There were no serious wound complications. Ninety-three participants completed feedback questionnaires. The median pain VAS score during the procedure was 7 mm (Interquartile range [IQR] 1-34), 4 mm (IQR 0-16) one day after the procedure and 1mm (IQR 0-4) 7 days after the procedure. 60 (65%) participants were back to their normal levels of activity one day after the procedure. 85 (91%) found this procedure acceptable and would have the procedure again.

CONCLUSION

Muscle biopsy using a Weil-Blakesley conchotome is both feasible and acceptable in community dwelling older men participating in epidemiological research. The excellent yield of biopsy tissue will allow morphological and molecular studies of muscle to be integrated into an epidemiological study facilitating investigation of the mechanisms underpinning sarcopenia that could potentially be altered by life course influences.

Improvement in out-of-hours outcomes following the implementation of Hospital at Night

BACKGROUND

Hospital at Night (H@N) is a Department of Health (England) driven programme being widely implemented across UK. It aims to redefine how medical cover is provided in hospitals during the out-of-hours period.

AIM

To investigate whether the implementation of H@N is associated with significant change in system or clinical outcomes.

DESIGN

An observational study for 14 consecutive nights before, and 14 consecutive nights after the implementation of H@N. Data were collected from the Combined surgical and medical Assessment Unit (CAU), the 18 medical/surgical wards (The Ward Arc) and the four High Dependency Units (The Critical Care corridor) within the Royal Infirmary of Edinburgh.

METHODS

Following an overnight episode of clinical concern, data were gathered on response time, seniority of reviewing staff, patient outcome and the use of Standardized Early Warning Score (SEWS).

RESULTS

Two hundred and nine episodes of clinical concern were recorded before the implementation of H@N and 216 episodes afterwards. There was no significant change in response time in the CAU, Ward Arc or Critical Care corridor. However, significant inter-speciality differences in response time were eradicated, particularly in the Critical Care corridor. Following the implementation of H@N, patients were reviewed more frequently by senior medical staff in CAU (28% vs. 4%, P < 0.05) and the Critical Care corridor (50% vs. 22%, P < 0.001). Finally there was a reduction in adverse outcome (defined as unplanned transfer to critical care/cardiac arrest) in the Ward Arc and CAU from 17% to 6% of patients reviewed overnight (P < 0.01). SEWS was more frequently and accurately recorded in CAU.

CONCLUSION

This is the first study that we are aware of directly comparing out-of-hours performance before and after the implementation of H@N. Significant improvements in both patient and system outcomes were observed, with no adverse effects noted.

Intrathecal ziconotide and opioid combination therapy for noncancer pain: an observational study

BACKGROUND

Intrathecal ziconotide is used to manage severe chronic pain. Although ziconotide is approved by the US Food and Drug Administration for monotherapy, it is sometimes used in combination with other intrathecal drugs for the management of intractable pain conditions in clinical practice.

OBJECTIVES

Evaluate the safety and tolerability of ziconotide combination therapy.

STUDY DESIGN

A retrospective, observational study.

SETTING

A single center.

METHODS

Patients with severe chronic pain of noncancer origin who were receiving inadequate analgesia with intrathecal opioid therapy (with or without intrathecal adjuvants) and who had ziconotide added to their intrathecal regimens were included. Patient characteristics, intrathecal ziconotide doses, concomitant intrathecal and systemic drug use, visual analog scale pain scores, Oswestry Disability Index scores, mini-mental status examination scores, neurological examination results, clinical observations (including adverse event reports), and equipment complications were reviewed for 12 weeks after ziconotide initiation.

RESULTS

Sixteen patients were identified. Ziconotide was initiated at a dose of 0.5 mcg/d and titrated to a mean dose of 2.64 mcg/d at week 12. Intrathecal opioids were hydromorphone (n=7), morphine (n=5), fentanyl (n=3), and sufentanil (n=1). Adverse events were noted in one patient, who reported increased depression and pain during combination therapy; ziconotide treatment was discontinued, and all adverse events resolved over a 4-week period. Substantial pain relief (> or =4-point decrease in visual analog scale score) was reported in 3 of 15 patients (20.0%) and increased functional capacity was evident in 3 of 15 patients (20.0%).

LIMITATIONS

A retrospective study with a limited number of patients from a single center.

CONCLUSION

Results from this observational study suggest that combination intrathecal ziconotide and opioid therapy may be a safe and potentially effective treatment option for patients with refractory chronic pain. Controlled, prospective clinical trials to evaluate ziconotide combination therapy are needed.

Skeletal and Cardiac Muscle Defects in a Murine Model of Emery-Dreifuss Muscular Dystrophy

Previous histological findings, physiological data, and behavioral observations on the A-type lamin knockout mouse (Lmna(-/-)) suggest that important aspects of this model resemble the human Emery-Dreifuss muscular dystrophy (EDMD) phenotype. The main goal of our experiments was to study skeletal and cardiac muscle function in this murine model to obtain the semiquantitative data needed for more detailed comparisons with human EDMD defects. Measurements of the mechanical properties of preparations from two different skeletal muscle groups, the soleus and the diaphragm, were made in vitro. In addition, records of the electrocardiogram, and measurements of heart rate variability were obtained; and phasic contractions (unloaded shortening) of enzymatically isolated ventricular myocytes were monitored. Soleus muscles from Lmna(-/-) mice produced less force and work than control preparations. In contrast, force and work production in strips of diaphragm were not changed significantly. Lead II electrocardiograms from conscious, restrained Lmna(-/-) mice revealed slightly decreased heart rates, with significant prolongations of PQ, QRS, and 'QT' intervals compared with those from control recordings. These ECG changes resemble some aspects of the ECG records from humans with EDMD; however, the cardiac phenotype in this Lmna(-/-) mouse model appears to be less well-defined/developed. Ventricular myocytes isolated from Lmna(-/-) mice exhibited impaired contractile responses, particularly when superfused with the beta-adrenergic agonist, isoproterenol (1 microM). This deficit was more pronounced in myocytes isolated from the left ventricle(s) than in myocytes from the right ventricle(s). In summary, tissues from the Lmna(-/-) mouse exhibit a number of skeletal and cardiac muscle deficiencies, some of which are similar to those which have been reported in studies of human EDMD.

An investigation of the action of the hamstring muscles during standing in crouch using functional electrical stimulation (FES)

The hamstring muscle moment arms indicate that they act as hip extensors and knee flexors. Previous work using induced acceleration (IA) analysis and functional electrical stimulation (FES) has, however, revealed counter-intuitive muscle actions, particularly for biarticular muscles during the stance phase of normal gait. In conditions such as cerebral palsy the hamstrings have been associated with the development of pathological gait patterns, particularly crouch gait. This study examines the role of these muscles in the control of crouched standing postures. Five unimpaired adult subjects had their muscles stimulated during quiet standing in different degrees of crouch. Kinematic and kinetic changes were observed and measured using a 3D motion analysis system. The hamstring muscles were shown to act strongly to retrovert the pelvis and extend the hip. The action at the knee changes as crouch increases, moving from flexing to extending.

Symptomatic nutritional rickets in a teenager with autistic spectrum disorder

Selectivity with food and food related behavioural difficulties are relatively common in children on the Autistic Spectrum. This may result in an inadequate nutritional status. Integration of sensory signals in the brain associated with textures, tastes and smells has been postulated as a possible cause.

Structure and function of enzymes involved in the biosynthesis of phenylpropanoids

As a major component of plant specialized metabolism, phenylpropanoid biosynthetic pathways provide anthocyanins for pigmentation, flavonoids such as flavones for protection against UV photodamage, various flavonoid and isoflavonoid inducers of Rhizobium nodulation genes, polymeric lignin for structural support and assorted antimicrobial phytoalexins. As constituents of plant-rich diets and an assortment of herbal medicinal agents, the phenylpropanoids exhibit measurable cancer chemopreventive, antimitotic, estrogenic, antimalarial, antioxidant and antiasthmatic activities. The health benefits of consuming red wine, which contains significant amounts of 3,4',5-trihydroxystilbene (resveratrol) and other phenylpropanoids, highlight the increasing awareness in the medical community and the public at large as to the potential dietary importance of these plant derived compounds. As recently as a decade ago, little was known about the three-dimensional structure of the enzymes involved in these highly branched biosynthetic pathways. Ten years ago, we initiated X-ray crystallographic analyses of key enzymes of this pathway, complemented by biochemical and enzyme engineering studies. We first investigated chalcone synthase (CHS), the entry point of the flavonoid pathway, and its close relative stilbene synthase (STS). Work soon followed on the O-methyl transferases (OMTs) involved in modifications of chalcone, isoflavonoids and metabolic precursors of lignin. More recently, our groups and others have extended the range of phenylpropanoid pathway structural investigations to include the upstream enzymes responsible for the initial recruitment of phenylalanine and tyrosine, as well as a number of reductases, acyltransferases and ancillary tailoring enzymes of phenylpropanoid-derived metabolites. These structure-function studies collectively provide a comprehensive view of an important aspect of phenylpropanoid metabolism. More specifically, these atomic resolution insights into the architecture and mechanistic underpinnings of phenylpropanoid metabolizing enzymes contribute to our understanding of the emergence and on-going evolution of specialized phenylpropanoid products, and underscore the molecular basis of metabolic biodiversity at the chemical level. Finally, the detailed knowledge of the structure, function and evolution of these enzymes of specialized metabolism provide a set of experimental templates for the enzyme and metabolic engineering of production platforms for diverse novel compounds with desirable dietary and medicinal properties.

Creation and characterization of E-selectin- and VCAM-1-deficient mice

A variety of adhesion molecules have been identified which mediate the interaction of leukocytes with endothelial cells. In order to define the role of individual molecules in inflammation we have produced lines of mice which are deficient in the synthesis of specific adhesion molecules. Null mutations were introduced into the genes encoding E-selectin or vascular cell adhesion molecule-1 (VCAM-1) in embryonic stem cells and these cells were used to produce lines of mice carrying the mutation. E-selectin-deficient mice were viable and exhibited no developmental defects. The roles of E- and P-selectin in the influx of neutrophils were examined using these mice. The data suggest that the two selectins are functionally redundant in mediating neutrophil emigration in a model of chemically induced peritonitis. VCAM-1-deficient mice are not viable. Analysis of VCAM-1 gene expression in wild-type embryos and phenotypic analysis of VCAM-1 -/- embryos suggests that VCAM-1 is required for development of the extraembryonic circulatory system and the embryonic heart.