Myonuclear alterations associated with exercise are independent of age in humans.

Age-related decline in skeletal muscle structure and function can be mitigated by regular exercise. However, the precise mechanisms that govern this are not fully understood. The nucleus plays an active role in translating forces into biochemical signals (mechanotransduction), with the nuclear lamina protein lamin A regulating nuclear shape, nuclear mechanics and ultimately gene expression. Defective lamin A expression causes muscle pathologies and premature ageing syndromes, but the roles of nuclear structure and function in physiological ageing and in exercise adaptations remain obscure. Here, we isolated single muscle fibres and carried out detailed morphological and functional analyses on myonuclei from young and older exercise-trained individuals. Strikingly, myonuclei from trained individuals were more spherical, less deformable, and contained a thicker nuclear lamina than those from untrained individuals. Complementary to this, exercise resulted in increased levels of lamin A and increased myonuclear stiffness in mice. We conclude that exercise is associated with myonuclear remodelling, independently of age, which may contribute to the preservative effects of exercise on muscle function throughout the lifespan. KEY POINTS: The nucleus plays an active role in translating forces into biochemical signals. Myonuclear aberrations in a group of muscular dystrophies called laminopathies suggest that the shape and mechanical properties of myonuclei are important for maintaining muscle function. Here, striking differences are presented in myonuclear shape and mechanics associated with exercise, in both young and old humans. Myonuclei from trained individuals were more spherical, less deformable and contained a thicker nuclear lamina than untrained individuals. It is concluded that exercise is associated with age-independent myonuclear remodelling, which may help to maintain muscle function throughout the lifespan.

Active GSK3ß and an intact ß-catenin TCF complex are essential for the differentiation of human myogenic progenitor cells.

Wnt-ß-catenin signalling is essential for skeletal muscle myogenesis during development, but its role in adult human skeletal muscle remains unknown. Here we have used human primary CD56Pos satellite cell-derived myogenic progenitors obtained from healthy individuals to study the role of Wnt-ß-catenin signalling in myogenic differentiation. We show that dephosphorylated ß-catenin (active-ß-catenin), the central effector of the canonical Wnt cascade, is strongly upregulated at the onset of differentiation and undergoes nuclear translocation as differentiation progresses. To establish the role of Wnt signalling in regulating the differentiation process we manipulated key nodes of this pathway through a series of ß-catenin gain-of-function (GSK3 inhibition and ß-catenin overexpression) or loss-of-function experiments (dominant negative TCF4). Our data showed that manipulation of these critical pathway components led to varying degrees of disruption to the normal differentiation phenotype indicating the importance of Wnt signalling in regulating this process. We reveal an independent necessity for active-ß-catenin in the fusion and differentiation of human myogenic progenitors and that dominant negative inhibition of TCF4 prevents differentiation completely. Together these data add new mechanistic insights into both Wnt signalling and adult human myogenic progenitor differentiation.

Nanoparticle Trapping and Characterization Using Open Microcavities.

Characterization and trapping of nanoparticles in solution is of great importance for lab-on-a-chip applications in biomedical, environmental, and materials sciences. Devices are now starting to emerge allowing such manipulations and investigations in real-time. Better insights into the interaction between the nanoparticle and the optical trap is therefore necessary in order to move forward in this field. In this work, we present a new kind of nanotweezers based on open microcavities. We show that by monitoring the cavity mode wavelength shift as the particle diffuses through the cavity, it is possible to establish both the nanoparticle polarizability and its coefficient of friction. Additionally, our experiment provides a deep insight in the interaction between the nanoparticle and the cavity mode. The technique has built-in calibration of the trap strength and spring constant, making it attractive for practical applications. This work illustrates the potential of such optical microcavities for future developments in nanoparticle sensors and lab-on-a-chip devices.

Open-access optical microcavities for lab-on-a-chip refractive index sensing.

Open-access optical microcavities provide a novel approach to label-free lab-on-a-chip optofluidic sensing. They offer direct access to a highly confined electromagnetic field, and yield a femtoliter detection volume. This article describes the characteristics of these devices for refractive index sensing. We show that most of the ambient noise can be removed from the refractive index data by simultaneous tracking of resonances across an array of cavities. A sensitivity of 3.5 × 10(-4) RIU is demonstrated which corresponds to detecting the refractive index change caused by the presence of 500,000 glucose molecules in aqueous solution.

Stable isotope imaging of biological samples with high resolution secondary ion mass spectrometry and complementary techniques.

Stable isotopes are ideal labels for studying biological processes because they have little or no effect on the biochemical properties of target molecules. The NanoSIMS is a tool that can image the distribution of stable isotope labels with up to 50 nm spatial resolution and with good quantitation. This combination of features has enabled several groups to undertake significant experiments on biological problems in the last decade. Combining the NanoSIMS with other imaging techniques also enables us to obtain not only chemical information but also the structural information needed to understand biological processes. This article describes the methodologies that we have developed to correlate atomic force microscopy and backscattered electron imaging with NanoSIMS experiments to illustrate the imaging of stable isotopes at molecular, cellular, and tissue scales. Our studies make it possible to address 3 biological problems: (1) the interaction of antimicrobial peptides with membranes; (2) glutamine metabolism in cancer cells; and (3) lipoprotein interactions in different tissues.

Acute effects of a herb extract formulation and inulin fibre on appetite, energy intake and food choice.

The impact of two commercially available products, a patented herb extract Yerbe Maté, Guarana and Damiana (YGD) formulation and an inulin-based soluble fermentable fibre (SFF), alone or in combination, on appetite and food intake were studied for the first time in a double blind, placebo-controlled, cross-over design. 58 normal to slightly overweight women consumed a fixed-load breakfast followed 4h later by an ad libitum lunch. They were administered YGD (3 tablets) and SFF (5g in 100ml water), YGD and water (100ml), SFF and placebo (3 tablets) or water and placebo 15min before meals. Appetite was assessed using visual analogue scales, and energy intake was measured at lunch. Significant reductions in food intake and energy intake were observed when YGD was present (59.5g, 16.3%; 112.4kcal, 17.3%) and when SFF was present (31.9g, 9.1%; 80kcal, 11.7%) compared with conditions were products were absent. The lowest intake (gram and kcal) was in the YGD+SFF condition. Significant reductions in AUC hunger and AUC desire to eat were also observed after YGD+SFF combination. The data demonstrate that YGD produces a robust short-term effect on caloric intake, an effect augmented by SFF. Caloric compensation for SFF indicates independent effects on appetite regulation.

Intra-operative 3-T MRI for paediatric brain tumours: challenges and perspectives.

MRI is the ideal modality for imaging intracranial tumours. Intraoperative MRI (ioMRI) makes it possible to obtain scans during a neurosurgical operation that can aid complete macroscopic tumour resection­a major prognostic factor in the majority of brain tumours in children. Intraoperative MRI can also help limit damage to normal brain tissue. It therefore has the potential to improve the survival of children with brain tumours and to minimise morbidity, including neurological deficits. The use of ioMRI is also likely to reduce the need for second look surgery, and may reduce the need for chemotherapy and radiotherapy. Highfield MRI systems provide better anatomical information and also enable effective utilisation of advanced MRI techniques such as perfusion imaging, diffusion tensor imaging, and magnetic resonance spectroscopy. However, high-field ioMRI facilities require substantial capital investment, and careful planning is required for optimal benefit. Safe ioMRI requires meticulous attention to detail and rigorous application of magnetic field safety precautions. Interpretation of ioMRI can be challenging and requires experience and understanding of artefacts that are common in the intra-operative setting.

Preparation of location-specific thin foils from Fe-3% Si bi- and tri-crystals for examination in a FEG-STEM.

Bi-crystals and tri-crystals of a nominal Fe-3% Si (wt%) of well-defined orientations have been grown using a floating-zone technique with optical heating. The manufacture of these unique crystals and the preparation technique involved in harvesting thin foils from specific locations for transmission electron microscopy are described in detail. In particular, the grain boundary triple junction has been extracted from the tri-crystal and examined in high-resolution aberration-corrected FEG-STEM instruments. To achieve the necessary resolution, the foils have to be uniformly thin, in the range 50-100 nm over large areas of the specimen. For ferromagnetic materials, there are further challenges arising from the magnetic field interaction, with the electron beam placing significant demands on the aberration correction system. One way to minimise this interaction is to reduce the total mass of magnetic material. To achieve this, an in situ focused ion beam lift-out technique has been combined with an additional precision ion-polishing stage to reproducibly provide thin-foil specimens suitable for high-resolution EELS and EDX analysis. Examination of the foils reveals that the final precision ion-polishing stage removes residual damage arising from the use of focused ion beam milling procedures.

Coping, depressive feelings and gender differences in late life widowhood.

The study investigated the relationship between depressive feelings and coping amongst older widowed men and women. Participants were interviewed about their affective experiences of widowhood and completed two depression questionnaire assessments, the Symptoms of Anxiety and Depression Scale (SAD) and the Hospital Anxiety and Depression Scale (HADS). Participants were assessed as either coping or not coping. The results showed that both measures were effective at differentiating those who coped (Copers) from those who did not (Non-Copers) in the sample as a whole. Amongst the widows the HADS significantly differentiated the two groups. Amongst men, neither measure significantly distinguished Copers from Non-Copers. However, an examination of the interviews suggested that widowers reported depressive feelings significantly more often than widows. The results suggest that depressive feelings are associated with non-coping in older widowed people. There is also evidence to suggest that widows and widowers respond differentially to assessment measures.

Colposcopy information leaflets: what women want to know and when they want to receive this information.

OBJECTIVES: To evaluate whether the information leaflets produced by UK colposcopy clinics provide women with the information they desire and to determine when they would like to receive this information. DESIGN: Questionnaire study and structured evaluation. SETTING: The colposcopy clinic of a UK cancer centre. PARTICIPANTS: Forty-two women attending a pre-colposcopy counselling session and 100 consecutive women attending the colposcopy clinic. METHODS: Thirty-eight standards derived from the concerns/questions asked by women attending a pre-colposcopy counselling session were used to assess locally produced colposcopy clinic leaflets from UK colposcopy clinics, the leaflets produced by the Royal College of Obstetricians and Gynaecologists and the National Health Service Cervical Screening Programme (NHSCSP), and two "leaflets" obtained from internet sites. The Gunning fog test was used to assess the leaflets' readability. A questionnaire survey of 100 women attending the colposcopy clinic was used to determine when women wanted to receive information about colposcopy. MAIN OUTCOME MEASURES: Percentage of questions answered by a given leaflet and Gunning fog scores for readability. RESULTS: The information leaflets of 128 colposcopy clinics were received and assessed. Thirty-two clinics only sent women the NHSCSP leaflet. No leaflet answered all 38 questions. Less than half (36/100) of the leaflets answered more than 50% of the questions. In addition to the lack of advice given, different leaflets frequently gave conflicting advice. The average Gunning fog score was 9.7 (range 5.5-15.5). The majority of women (70%) wanted to receive information about colposcopy at or prior to the time of receiving their abnormal smear test result, although only 42% of women actually received information at this time. CONCLUSIONS: Many UK colposcopy clinics do not appear to be providing women with the information they require to understand their condition and the procedure that they are about to undergo. Furthermore, this information is often not provided at the appropriate time in the screening process.

Can pre-colposcopy sessions reduce anxiety at the time of colposcopy? A prospective randomised study.

The main objective of this prospective randomised study was to evaluate whether offering pre-colposcopy group sessions reduces anxiety at the time of colposcopy. We also examined whether this strategy improved knowledge about abnormal smears and colposcopy and improved satisfaction with the colposcopy service provided. One hundred and forty-seven women undergoing colposcopy for the first time were randomised into two groups. The control group (n = 75) received conventional management. The study group (n = 72), in addition to conventional management, were invited to attend a pre-colposcopy group session led by a trained colposcopy nurse. Questionnaires were used to determine state anxiety inventory scores and knowledge scores at the time of randomisation, immediately before colposcopy and 6 weeks after the clinic visit. Satisfaction questionnaires were completed 6 weeks after the clinic visit. We found that women attending colposcopy clinics are anxious. Those women who attended the pre-colposcopy session had improved knowledge scores (P = 0.039) at the time of colposcopy and satisfaction (P = 0.037). However, the intervention failed to significantly reduce anxiety at the time of colposcopy (P > 0.05).

Richard Pattle and the early days of comparative respiratory biology.

After a distinguished academic career Richard Pattle was well qualified as a Physicist and Physical Chemist. Following a brief spell in the army (REME) he was appointed as a biophysicist in the Chemical Defence Experimental Laboratory at Porton Down. Such centres here and in USA initiated work which led to important discoveries relating to lung surfactants. His 1955 paper led to an expansion in studies of surfactant and the lung lining and appreciation of its importance in Respiratory Distress Syndrome of the newborn. This period (late 1950s and 1960s) was also when comparative studies in respiration were beginning to expand. Because of the relevance of his work to RDS it was inevitable that Pattle became closely associated with Human Physiologists. But he was also interested in other mammals and later the lungs of primates and lower vertebrates and this was extended to fish and the transition from water to air breathing. It was a time notable for the getting-together of medically-trained and zoologically-based scientists. I was always fascinated by the simplicity of his bubble technique and encouraged him to summarise it and his findings at Bhagalpur in 1974 when he introduced the term 'surpellic'. He also made important studies on bird lung surfactants.

A comparison of blood composition in the common carp (Cyprinus carpio L.) using samples obtained from caudal vessels and dorsal aorta cannulae.

Blood samples have been taken from chronic cannulae in the dorsal aorta of Carp under anaesthesia and at intervals of 24, 29 and 101 hours later. A few minutes after the 29 hours and 101 hours sampling was completed similar quantities (1 ml) were withdrawn from a caudal vessel. All samples were treated in the same way and determinations made of haematocrit value, total protein, glucose concentration and activity of the following plasma enzymes-acetylcholinesterase (AChE), glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT) and lactic dehydrogenase (LDH). Comparisons between dorsal aorta and caudal samples at 29 hours and 101 hours showed no significant differences for any of the enzyme activities that were tested. However significant (paired "t"-test, P < 0.05) differences were observed for haematocrit and glucose concentration. It is suggested that the higher haematocrit and lower glucose of caudal samples are consistent with the expected differences between arterial and venous blood. Apart from these differences which reflect normal physiological function, values obtained for samples from the two sites were identical. It is concluded that blood sampling from caudal vessels is a satisfactory method to obtain blood for biomonitoring purposes at least for those enzymes commonly used in recent surveys.

Study of the effects of brief exposure to an organophosphorous insecticide (methidathion) on blood characteristics of carp (Cyprinus carpio).

1. Carp with the dorsal aorta cannulated have been used to study the effects of a 5 hour exposure to methidathion at concentrations of 2 or 6 mg/litre. Blood samples taken during control, exposed and recovery periods were used to determine plasma acetylcholinesterase (AChE) activity, haematocrit value, mean cell volume, total plasma protein, and filtration time through Nucleopore filters containing pores of 8 microns. 2. A drastic inhibition of AChE activity was observed and this continued during the recovery for at least 5 days. Changes in other blood parameters were less marked and recovered soon after fish were returned to non-polluted water. The increased haematocrit and decrease in filtration time suggests some impairment of gas transfer during exposure but the depletion of AChE activity and associated muscular and neural disturbances are more serious results of pollution with this organophosphate insecticide.

The relationship of sustained exercise training and bone mineral density in aging male runners.

Fifty-six men aged 42-73 years (50.2 +/- 10.0 years), who were competitive distance runners 20-25 years previously, were examined for bone mineral density (BMD) to determine the relationship between sustained distance running and BMD. Subjects were classified as being highly trained (HT, n = 17), moderately trained (MT, n = 29) or untrained (UT, n = 10) according to their training in recent years. Subjects in each group were of similar age (HT 46.5 +/- 2.01, MT 53.0 +/- 1.51, UT 46.7 +/- 2.44 years) and lean body mass. Total body weight (kg) and percentage fat, however, were significantly greater (P < 0.05) in the UT group than in either the MT or HT groups (UT 80.6 +/- 2.44 kg, 22.0 +/- 1.16%; MT 74.9 +/- 1.51 kg, 17.5 +/- 0.61%; HT 70.5 +/- 1.71 kg, 13.5 +/- 0.59%). Lumbar vertebrae and hip region BMD (g.cm-2) was determined via dual energy X-ray absorptiometry (DEXA). No differences in BMD were found among the three groups in either the lumbar (HT 1.00 +/- 0.02, MT 1.02 +/- 0.03, UT 1.07 +/- 0.04 g.cm-2) or the hip regions (HT 0.99 +/- 0.03, MT 0.98 +/- 0.02, UT 1.06 +/- 0.04 g.cm-2). Furthermore, none of the groups had BMD that was significantly different from age-matched normative values taken from a reference database. A moderate correlation was found between body weight and BMD when combining all subjects (r = 0.38 for lumbar and r = 0.41 for hip). These results indicate that middle-aged to older males who have sustained exercise training in the form of running do not have significantly different lumbar vertebrae or hip region BMD compared to individuals who run less or not at all.

The influence of red cell size relative to pore size on filtration through nuclepore filters.

A simple model relating pore passage time (PPT) to the degree of strain of the membrane of a red cell of diameter DC on passing through a pore (diameter Dp) has been developed. The model was tested for a range of mammalian and fish species for which some data was available for more than one pore size. The strain (epsilon) is estimated as (Dc-Dp)/Dc. For small epsilon, less than approximately 0.45, PPT was small but rose rapidly for higher values. The analysis provides a simple basis for choosing appropriate pore sizes, and consequently strain, for comparing mechanical properties of erythrocytes of different species.

Effects of low environmental pH in the presence of aluminum on filtration properties of the blood of atlantic salmon (Salmo salar L.).

The time for filtration of whole blood samples through 8 microns pores of polycarbonate membranes provides an index of the deformability of fish red blood cells. Comparison of these and other haematological measurements on salmon before and after exposure to pH 5.0 and 20 microM aluminium for 2 hours shows changes which are indicative of hypoxia. The increase in deformability of the red cells will assist transfer of oxygen from the gills to the tissue cells and hence compensate environmental hazards of low pH and aluminium.

Swimming performance of rainbow trout following exposure and recovery from the pyrethroid S-deltamethrin.

Oxygen consumption and swimming performance of rainbow trout exposed to sublethal concentrations (10-50 microliters/20 L) of pyrethroid (S-deltamethrin) pesticide was studied in a Brett-type respirometer during recovery. Results showed wide variations reflecting the varied responses of different individual fish to the test regime. In most cases values of oxygen consumption for the controls were higher at each swimming speed and this became significantly reduced following treatment with pesticide. Oxygen consumption soon after the treatment gave the highest values but these fish were unable to sustain swimming speeds as high as the controls or following recovery. The comparisons of swimming performance before and after treatments with deltamethrin have shown a significant effect on locomotory ability of rainbow trout which at the end of strong exposure (e.g. 50 min of 40 microliters/20 L) are almost incapable of swimming.

Routine oxygen consumption in different sizes of a tilapia, Oreochromis niloticus (Trewavas) using the closed chamber respiratory method.

Routine oxygen consumption (Vo2) measurements on 54 specimens (0.055-190.4 g) of a tilapia, Oreochromis niloticus (Trewavas) were carried out using two different types of closed respirometers: a modified cuvette for fish weighing 0.055-0.91 g and ordinary closed chamber respirometer for fish weighing more than 1 g. Vo2 values over the weight range studied had a scaling value of 0.743 which relates closely to the values for the gill respiratory surface area and morphometric oxygen diffusing capacity of O. niloticus in a previous study /13/. This shows that a close relationship exists between changes in structural parameters involved in oxygen uptake and the routine metabolism of O. niloticus with development. The values for routine Vo2 of 1.38 and 7.65 ml/h for 10 g and 100 g fish, respectively (calculated from the regression equation) show that O. niloticus is a moderately active fish.

Structure of the respiratory islets of accessory respiratory organs and their relationship with the gills in the climbing perch, Anabas testudineus (Teleostei, Perciformes).

The epithelial and sub-epithelial organization of the accessory respiratory organs of Anabas testudineus has been compared with that of gills by using light and transmission electron microscopy. The details of vascular supply of respiratory islets (RI) and gill filaments and the presence of venous sinusoids in the two systems suggest that the RI have been derived from gill filaments and lamellae. The biserial arrangement of transverse capillaries (TC) in the respiratory islets (RI) is evident under the scanning electron microscope and their homology with the gill filaments and their secondary lamellae has been established. The two sets of transverse capillaries of respiratory islets have been derived either from embryonic transverse or marginal channels of two sets of lamellae of a gill filament. These capillaries with their endothelial septate valves and tongue-like processes offer resistance to blood flow. Gill filaments have two vascular pathways, arterio-arterial and arterio-venous. However, the RI of accessory respiratory organs contain the arterio-venous pathways. This arrangement as well as the septate transverse capillaries may lower the "pulmonary" blood pressure considerably. Two types of mitochondria-rich cells are identified: i) chloride cells with flat microvilli bearing surfaces, devoid of apical pit and (ii) an elongated cell type with sac-like endoplasmic reticulum, with apical pit that comes into close contact with the complex matrix of macrophages, lymphocytes and other loose cells of the epithelium. These cells may be associated with detoxification of the internal media of fish inhabiting foul waters.