bluuebunny/crossref_metadata_2025 huggingface dataset:
Leptin receptor Gln223Arg variant is associated with a cluster of metabolic abnormalities in response to long‐term overfeeding
Authors: Ukkola O. , Tremblay A. , Després J.‐P. , Chagnon Y. C. , Campfield L. A. , Bouchard C.
Published: March 2003

Abstract. Ukkola O, Tremblay A, Després J‐P, Chagnon YC, Campfield LA, Bouchard C (Pennington Biomedical Research Center, Baton Rouge, Louisiana, USA; University of Oulu, Oulu, Finland; Laval University, Ste‐Foy, Québec, Canada; and University of Colorado Health Sciences Center, Denver, Colorado, USA). Leptin receptor Gln223Arg variant is associated with a cluster of metabolic abnormalities in response to long‐term overfeeding. J Intern Med 2000; 248: 435–439.

Objectives. The role of the leptin receptor (LEPR) gene Gln223Arg polymorphism on the metabolic and body composition changes in response to overfeeding was studied.

Subjects. Twelve pairs of male monozygotic twins ate a 4.2 MJ day–1 energy surplus, 6 days week–1, during a period of 100 days.

Results. Overfeeding induced a significantly greater increase in glucose (P = 0.001 for percentage change) and insulin (P = 0.038) areas under the curve during oral glucose tolerance tests (OGTTs) in the GlnGln (n = 10) than in the GlnArg/ArgArg (n = 14) subjects. In addition, the GlnGln genotype was associated with a greater increase in plasma levels of leptin (P = 0.037) and total triglycerides (P = 0.003), as well as a greater decrease in high‐density lipoprotein cholesterol (P = 0.010), than for the combined GlnArg/ArgArg genotypes. Body composition changes were not different between the genotypes.

Conclusions. We conclude that the GlnGln subjects of the LEPR gene polymorphism are more susceptible to metabolic abnormalities when they are exposed to long‐term positive energy balance. These findings provide new information on the genetic basis of individual differences in response to chronically elevated food intake.
Increased erythrocyte content of Ca2+ in patients with Tarui's disease
Authors: Waldenström A. , Engström I. , Ronquist G.
Published: March 2003

Abstract. Waldenström
A,
Engström
I,
Ronquist
G (Norrlands University Hospital, Umeå; and University Hospital, Uppsala; Sweden). Increased erythrocyte content of Ca2+ in patients with Tarui's disease. J Intern Med 2001; 249: 97–102.

Objectives. To establish by flow cytometry and fluorophores an increased calcium ion load in erythrocytes of four patients with Tarui's disease.

Design. Calcium ion levels were determined in erythrocytes of patients and controls under normal and energy‐deprived conditions. Adenylates were measured to assess energy status of incubated erythrocytes.

Setting. The experiments were carried out at the Department of Clinical Chemistry of the University Hospital of Uppsala, Sweden.

Subjects. Four family members with Tarui's disease participated in the study. The proband (patient 1) was a 39‐year‐old male; patients (male, aged 46 years) 2 and 3 (female, 30 years) were his two siblings. Patient 4 (male, 16 years) was the son of patient 2.

Interventions. None.

Main outcome measures. Calcium ion homeostasis was measured under basic conditions and under energy‐deprived conditions and related to cellular adenylate content.

Results. All patients showed enhanced erythrocyte calcium ion loading compared to controls under energy‐deprived conditions. Under normal conditions, however, three out of the four patients showed an increased erythrocyte calcium ion level compared to controls.

Conclusions. We conclude that erythrocytes from patients with Tarui's disease have an increased Ca2+ permeability, initiating compensatory mechanisms involving increased Ca2+ pump activity and increased glycolytic flux, which are not always sufficient to keep erythrocyte calcium ion concentration within physiological range.
Large differences in serum leptin levels between nonwesternized and westernized populations: the Kitava study
Authors: Lindeberg S. , Söderberg S. , Ahrén B. , Olsson T.
Published: March 2003

Abstract. Lindeberg S, Söderberg S, Ahrén B, Olsson T (Lund University; and Umeå University, Malmö, Sweden). Large differences in serum leptin levels between nonwesternized and westernized populations: the Kitava study.J Intern Med2001;249:553–558.

Objectives. To compare serum leptin between nonwesternized and westernized populations.

Setting.  (i) The tropical island of Kitava, Trobriand Islands, Papua New Guinea and (ii) the Northern Sweden MONICA study population.

Design. Cross‐sectional survey.

Methods. Fasting levels of serum leptin were analysed in 163 randomly selected Kitavans aged 20–86 years and in 224 Swedes aged 25–74.

Main outcome measures. Mean and determinants of serum leptin.

Results. Geometric mean of serum leptin in Kitavan males and females were 1.5 and 4.0 vs. 4.9 and 13.8 ng mL−1in Swedish male and females (P < 0.0001 for both sexes). In Kitavans, observed geometric mean were close to predicted levels (1.8 ng mL−1for males and 4.5 ng mL−1for females) based on multiple linear regression equations including body mass index (BMI), triceps skinfolds (TSF) and age from the Swedish population‐based sample. In Kitavans serum leptin was positively related to TSF amongst both sexes and, amongst females, to BMI. In Kitavans leptin was not related to fasting serum insulin. TSF explained 55% of the variation of leptin amongst females. There was a slight age‐related increase of leptin amongst males. In Kitava leptin was not related to fasting serum insulin which was substantially lower than in Sweden.

Conclusion. The low concentrations of serum leptin amongst Kitavans probably relates to the absence of overweight and hyperinsulinaemia. At a population level serum leptin can apparently be predicted from simple measures of adiposity.
Asymptomatic versus symptomatic persistent atrial fibrillation: clinical and noninvasive characteristics
Authors: Frykman V. , Frick M. , Jensen‐Urstad M. , Östergren J. , Rosenqvist M.
Published: March 2003

Abstract. Frykman V, Frick M, Jensen‐Urstad M, Östergren J, Rosenqvist M (South Hospital and Karolinska Hospital, Karolinska Institute, Stockholm, Sweden). Asymptomatic versus symptomatic persistent atrial fibrillation: clinical and noninvasive characteristics. J Intern Med 2001; 250: 390–397.

Objective. This prospective study was designed to investigate the differences between asymptomatic versus symptomatic arrhythmia as well as left ventricular dysfunction in a consecutive population of patients with persistent atrial fibrillation.

Design. A total of 282 consecutive outpatients referred with persistent atrial fibrillation formed the study population. A structured medical history was obtained. A two‐dimensional transthoracic echocardiography to assess the left ventricular function and a 24‐h electrocardiogram (ECG) recording were performed. Irregularity of the heart rhythm was analysed with heart rate variability (HRV) in the time domain as well as maximum and minimum heart rate and the longest pause.

Setting. Three university hospitals.

Results. The mean age of the patients was 69 years and the mean duration of atrial fibrillation was 7 months. The prevalence of symptomatic patients was 68%, while 32% had no symptoms from atrial fibrillation, left ventricular dysfunction was observed in 20%. Asymptomatic subjects had more often lone atrial fibrillation than those with symptoms. Valvular heart disease was an independent predictor of symptoms while male gender, ischaemic heart disease and a high heart rate were independent predictors of impaired left ventricular function.

Conclusion. Valvular heart disease is related to symptoms in persistent atrial fibrillation. Ischaemic heart disease, male gender and a high heart rate are more common in patients with impaired left ventricular function. Compromised left ventricular function does, occur also in asymptomatic subjects underlining the importance of a careful investigation including echocardiography in all subjects with persistent atrial fibrillation.
Progress in the development of immunotherapy for the treatment of patients with cancer
Authors: Rosenberg S. A.
Published: March 2003

Abstract. Rosenberg SA (National Cancer Institute, Institutes of Health, Bethesda, MD, USA). Progress in the development of immunotherapy for the treatment of patients with cancer (Review). J Intern Med 2001; 250: 462–475.

Several recent developments have hallmarked progress in tumour immunology and immunotherapy. The use of interleukin‐2 (IL‐2) in cancer patients demonstrated that an immunological manipulation was capable of mediating the regression of established growing cancers in humans. The identification of the genes encoding cancer antigens and the development of means for effectively immunizing patients against these antigens has opened important new avenues of exploration for the development of effective active and cell‐transfer immunotherapies for patients with cancer.
Both cerivastatin and fenofibrate improve arterial vasoreactivity in patients with combined hyperlipidaemia
Authors: ŠEBEŠTJEN M. , ŽEGURA B. , KEBER I.
Published: March 2003

Abstract. Šebeštjen M, Žegura B, Keber I (Department of Angiology, Hospital of Internal Medicine, University Clinical Centre, Ljubljana, Slovenia). Both cerivastatin and fenofibrate improve arterial vasoreactivity in patients with combined hyperlipidaemia. J Intern Med 2002; 251: 77–85.

Objectives. The aim of this study was to compare the effects of cerivastatin and fenofibrate on endothelium dependent and independent arterial dilation.

Design. In a prospective, double blind study, 38 overweight, nonsmoking, males aged between 40 and 60 years with combined hyperlipidaemia were randomized and, after 6 weeks run‐in phase with American Heart Association step I diet treatment, submitted to 12 weeks' treatment either with fenofibrate (250 mg daily) or cerivastatin. Cerivastatin was given in a daily dose of 0.2 mg for 6 weeks and was increased to 0.4 mg daily, if the LDL‐C did not decrease below 3.0 mmol L−1. Flow‐mediated (endothelium‐dependent) dilation (FMD) and nitroglycerin‐induced (endothelium‐independent) [gliceryltrinitrate (GTN)] dilation of brachial artery were measured using high resolution ultrasound.

Results. The FMD increased from 3.4 ± 3.3 to 9.3 ± 2.4% (P < 0.001) in the cerivastatin group, and from 3.3 ± 2.8 to 6.5 ± 3.1% (P < 0.001) in the fenofibrate group, the improvement being significantly better after cerivastatin (P=0.006). GTN increased from 11.5 ± 4.1 to 16.2 ± 3.5% (P < 0.01) and from 11.1 ± 2.5 to 16.0 ± 2.9% (P < 0.01), respectively, with no difference between the groups. Cerivastatin reduced total cholesterol by 24%, LDL‐cholesterol by 31%, triglycerides by 24%, ox‐LDL by 29% and increased HDL‐cholesterol by 5%, whilst, after fenofibrate, these changes were −15, −13, −41, −17 and 18%, respectively. Only the decrease of LDL‐C turned out to be an independent predictor the FMD improvement. The improvement in GTN‐induced dilation did not correlate with the changes in blood lipids.

Conclusions. Both cerivastatin and fenofibrate lead to an improvement of endothelium‐dependent and endothelium‐independent dilation of brachial artery in overweight patients with combined hyperlipidaemia and no other atherosclerotic risk factors. The effects on FMD were greater in subjects receiving cerivastatin than in subjects receiving fenofibrate, but the effects on GTN were equal in both groups.
Effects of simvastatin and atorvastatin on inflammation markers in plasma
Authors: WIKLUND O. , MATTSSON‐HULTÉN L. , HURT‐CAMEJO E. , OSCARSSON J.
Published: March 2003

Abstract. Wiklund O, Mattsson‐Hultén L, Hurt‐Camejo E, Oscarsson J. Effects of simvastatin and atorvastatin on inflammation markers in plasma (Sahlgrenska University Hospital and Göteborg University, Göteborg, Sweden). J Intern Med 2002; 251: 338–347.

Objectives. To study the effect of statins on plasma markers for inflammation.

Design.  Patients with hypercholesterolemia were randomized in one of the following treatments: Simvastatin (S) + placebo: S 40 mg for 6 weeks – S 80 mg for 6 weeks – S 80 mg for 24 weeks and Atorvastatin (A) + placebo: A 20 mg for 6 weeks – A 40 mg for 6 weeks – A 80 mg for 24 weeks.

Subjects. Forty‐seven patients with hypercholesterolemia were recruited in four different outpatient clinics.

Main outcome measures. Samples were obtained at randomization after 6, 12 and 36 weeks. Plasma or serum was analysed for lipids and for inflammation markers: C‐reactive protein (CRP), serum amyloid A (SAA), soluble phospholipase A2 (SPLA2), intercellular adhesion molecule‐1 (ICAM‐1) and interleukin‐6 (IL‐6).

Results. The reduction in LDL was similar for the two statins, except at the highest dose of atorvastatin (41 vs. 47%). The increase in HDL tended to be more pronounced in the simvastatin group, significantly so on the highest dose of atorvastatin (P < 0.05). CRP and SAA was significantly reduced by atorvastatin, whilst no reduction was seen for simvastatin. There was a significant difference in treatment effects between the two statins. Both statins caused a reduction in SPLA2. For IL‐6 and ICAM‐1 only small and inconsistent reductions were observed for both statins.

Conclusion. Atorvastatin reduced the liver‐derived acute‐phase reactants, CRP and SAA, whilst the effect of simvastatin was small or absent. Small and inconsistent effects were seen for both statins on plasma levels of IL‐6 and ICAM‐1.
Inflammatory bio‐markers and cardiovascular risk prediction
Authors: Blake G. J. , Ridker P. M.
Published: March 2003

Abstract. Blake GJ, Ridker PM (Harvard Medical School, Boston, MA, USA). Inflammatory bio‐markers and cardiovascular risk prediction (Review). J Intern Med 2002; 252: 283–294.

Inflammatory processes are now recognized to play a central role in the pathogenesis of atherosclerosis and its complications. Plasma levels of several markers of inflammation have been found to be associated with future cardiovascular risk in a variety of clinical settings. These markers include cell adhesion molecules, cytokines, pro‐atherogenic enzymes and C‐reactive protein (CRP). Initially thought of as an inactive downstream marker of the inflammatory cascade, emerging evidence suggests that CRP may be directly involved in atherogenesis, and that arterial plaque can produce CRP, independent of traditional hepatic pathways. In addition to being a strong predictor of future cardiovascular risk amongst patients presenting with acute coronary syndromes, numerous studies have found that baseline levels of CRP are associated with risk of future myocardial infarction, stroke, peripheral vascular disease and cardiovascular death amongst apparently healthy populations. The combination of measurement of a marker of inflammation with lipid testing may improve upon risk stratification based on lipid testing alone, and intensification of programmes for exercise, weight loss, and smoking cessation is recommended for those with elevated CRP levels. Further trials are needed to confirm the potential benefits of statins amongst individuals with elevated CRP levels.
The effect of streptokinase neutralizing antibodies on fibrinolytic activity and reperfusion following streptokinase treatment in acute myocardial infarction
Authors: Nilsson J. B. , Nilsson T. K. , Jansson J.‐H. , Boman K. , Söderberg S. , Näslund U.
Published: March 2003

Abstract. Nilsson JB, Nilsson TK, Jansson J‐H, Boman K, Söderberg S, Näslund U (Heart Centre, University Hospital, Umeå; Örebro Medical Centre, Örebro; Skellefteå Hospital, Skellefteå; Sweden). The effect of streptokinase neutralizing antibodies on fibrinolytic activity and reperfusion following streptokinase treatment in acute myocardial infarction. J Intern Med 2002; 252: 405–411.

Objectives. To evaluate tissue plasminogen activator (tPA) activity as a measure of fibrinolytic response to treatment with streptokinase (SK) and to relate this to the effect of pretreatment SK antibodies and to successful reperfusion assessed by continuous computerized vectorcardiography (VCG).

Setting. Umeå University Hospital.

Subjects. A total of 104 patients with acute myocardial infarction (AMI) treated with SK and no history of previous SK treatment were studied. The tPA activity was measured 4 h after the start of treatment. The effect of pre‐existing neutralizing antibodies to SK was analysed with a functional assay in pretreatment samples. Reperfusion was evaluated with VCG.

Main outcome measures. Successful reperfusion.

Results. Fifty‐five patients (53%) were classified as successfully reperfused. The risk for failed reperfusion was calculated in logistic regression models. In a univariate model, a borderline significant increase in the risk of failed reperfusion was observed in intermediate levels of SK neutralizing antibodies, but not in the highest levels. In a multivariate model, only high tPA activity, >25 U mL−1, at 4 h (OR 0.17; 95% CI: 0.06–0.51) was associated with a higher rate of reperfusion whilst longer time to treatment (OR 1.17; 95% CI: 1.02–1.35) was associated with a higher risk of failed reperfusion. There was no significant correlation between neutralizing antibodies to SK and tPA activity at 4 h.

Conclusion. The SK treatment of AMI induced high levels of tPA activity which were associated with successful reperfusion. The effect of pre‐existing SK antibodies had no significant influence on reperfusion and were not correlated to the fibrinolytic activity obtained.
Folic acid enhances endothelial function and reduces blood pressure in smokers: a randomized controlled trial
Authors: Mangoni A. A. , Sherwood R. A. , Swift C. G. , Jackson S. H. D.
Published: March 2003

Abstract.  Mangoni AA, Sherwood RA, Swift CG, Jackson SHD (Guy's, King's, and St Thomas' School of Medicine, King's College London, UK). Folic acid enhances endothelial function and reduces blood pressure in smokers: a randomized controlled trial. J Intern Med 2002; 252: 497–503.

Objective.  Cigarette smoking is associated with increased plasma homocysteine concentrations, endothelial dysfunction and arterial stiffening. Homocysteine per se induces endothelial dysfunction and arterial stiffening and might account, at least partly, for the vascular abnormalities observed in smokers. We sought to determine whether folic acid supplementation, by reducing plasma homocysteine concentrations, enhanced endothelial function and reduced arterial stiffness in smokers.

Design.  Double‐blind, randomized controlled, parallel‐group, trial.

Setting. Academic medical centre.

Subjects.  A consecutive sample of 24 healthy cigarette smokers (age 37.8 ± 2.5 years, mean ± SEM).

Intervention.  Subjects were randomly assigned to 4‐week folic acid 5 mg day−1 or placebo.

Main outcome measures.  The following were measured before and after treatment: (i) peripheral vasoreactivity (forearm arterial blood flow, FABF) during intra‐arterial administration of endothelium‐dependent (acetylcholine 1.5, 4.5 and 15 μg min−1) and endothelium‐independent (sodium nitroprusside 1, 2 and 4 μg min−1) vasodilators; (ii) carotid‐femoral pulse‐wave velocity (PWV); (iii) blood pressure (BP).

Results.  Folic acid reduced homocysteine concentrations (10.8 ± 0.6 vs. 8.2 ± 0.5 μmol L−1, P < 0.001) and enhanced endothelium‐dependent vasodilatation during each acetylcholine infusion rate (ratio between the FABF in the infused and control arm during increasing infusion rates at baseline 1.09 ± 0.03 vs. 1.41 ± 0.09 after treatment, P < 0.01; 1.39 ± 0.07 vs. 1.83 ± 0.12, P < 0.01; 1.65 ± 0.16 vs. 2.72 ± 0.36, P < 0.05) whilst endothelium‐independent vasodilatation was unaffected. A significant fall in BP was also observed (mean BP 88 ± 2 vs. 83 ± 1 mmHg, P < 0.01). By contrast, PWV did not significantly change (8.4 ± 0.3 vs. 7.8 ± 0.4 m s−1). No significant changes in plasma homocysteine concentrations, FABF, BP, and PWV were observed in the placebo group. A multiple regression analysis showed that changes in folic acid plasma concentrations independently predicted both FABF changes during maximal acetylcholine‐mediated vasodilatation (P < 0.01) and BP changes (P = 0.01).

Conclusions.  Short‐term folic acid supplementation significantly enhanced endothelial function and reduced BP in young chronic smokers. These effects were largely independent from the homocysteine lowering effects. Thus, a simple, nontoxic, and relatively inexpensive vitamin intervention might be useful in primary cardiovascular prevention in this high‐risk group.
The effect of detector size on the signal‐to‐noise ratio in confocal polarized light microscopy
Authors: Wilson  , Török  , Higdon
Published: March 2003

We introduce a signal‐to‐noise ratio in an attempt to suggest an optimum pinhole size for confocal polarized light microscopes. We find that pinhole sizes which are typically 60% greater than those used in nonpolarized light confocal microscopy are appropriate.
Improving image quality by zero‐loss energy filtering: quantitative assessment by means of image cross‐correlation
Authors: Grimm  , Typke  , Baumeister
Published: March 2003

Fourier ring correlation and root‐mean‐square contrast of pairs of images, taken under identical conditions, were used as criteria of image quality for comparing unfiltered with zero‐loss energy‐filtered imaging using a TEM equipped with a post‐column energy filter. For three different specimens (amorphous carbon film, macromolecules in light negative stain, virus particles in deep negative stain) the dependence of these quantities on electron dose, specimen thickness and defocus was investigated. A model, based on simple assumptions, was used to describe quantitatively their dependence on electron dose and specimen thickness. It was found that energy filtering is most advantageous for low‐dose imaging and small defocus values. The gain due to energy filtering strongly increases with specimen thickness, whereby the dependence is linear for light scattering elements. For thick specimens, the gain by energy filtering is more pronounced in the resolution range between 4 and 2 nm than for lower spatial frequencies.
Improved staining of F‐actin and co‐localization of mitochondria in plant cells
Authors: Olyslaegers G. , Verbelen J. ‐P.
Published: March 2003

Permeating the cell membrane with glycerol instead of detergents (e.g. NP‐40) and/or organic solvents (e.g. DMSO) significantly improves the visualization of F‐actin with rhodamine phalloidin. In particular, the thinnest bundles are more intensely stained, better delineated and observation time is prolonged dramatically. Furthermore, the method is gentle to membranous organelles, which makes, for example, co‐localization of mitochondria and actin possible.
Inversion of nonperiodic wavefields to determine localized defect structure
Authors: Beeching M. J , Spargo A. E. C
Published: March 2003

A methodology for obtaining high‐resolution crystal structure potential distributions from electron microscope images of defects is examined using image simulation methods. The technique is based on the inversion of the multislice procedure when extended to nonperiodic potentials. The sensitivity of the method to the defect model and position in the crystal is examined briefly with the preliminary conclusion that this should not severely limit the applicability of the method. The major impediment for the successful experimental application of the method to the detection and structure determination of single, isolated self‐interstitial defects in silicon is likely to be the preparation and fixation of the surfaces of the specimen.
Optimal and near‐optimal filters in high‐resolution electron microscopy
Authors: Kilaas R.
Published: March 2003

Two filters for improving the visibility of crystalline material in the presence of amorphous surface contamination layers in high‐resolution electron microscope images can be constructed automatically from the information present in the Fourier transform of the recorded image. The recorded signal is considered in the first approximation to be the sum of two signals which are uncorrelated in the frequency domain. By estimating the power spectrum of the signal from the amorphous layer, an optimized estimate for the desired signal is given by the Wiener filter. A second filter which uses the estimated amplitude of the amorphous signal to subtract out a background can be shown to be related to the Wiener filter. The two filters are applied to an experimental image of zeolite and the effects of the two filters are compared.
Analysis of integrin (CD11b/CD18) movement during neutrophil adhesion and migration on endothelial cells
Authors: Rochon  , Kavanagh  , Harlan
Published: March 2003

Little is known of the distribution of cell surface molecules during the adhesion and migration of leucocytes on endothelial cells. We have used confocal microscopy and a Fab fragment of a non‐inhibitory monoclonal antibody recognizing the integrin CD11b/CD18 (Mac‐1) to study the movement of this adhesion molecule over time. We found that during the initial stage of neutrophil contact with TNF‐α activated human umbilical vein endothelial cells (HUVEC), there is a rapid accumulation of Mac‐1 at the contact area between the two cell types. As the neutrophil spreads, Mac‐1 redistributes away from this initial contact area. During neutrophil migration on HUVEC, Mac‐1 was redistributed to the leading edge of the migrating cell, suggesting that the existing cell surface pool of adhesion molecules is dynamic and can be recruited to the leading front as the cell changes direction. As neutrophils migrate on HUVEC, Mac‐1‐dense macroaggregates are rapidly formed and broken down at the contact plane between the two cells. The confocal microscope, coupled with the use of non‐inhibitory antibodies labelled with photostable fluorophores, is a useful tool for the study of the movement of cell surface molecules over time.
Studies of a magnetically focused electrostatic mirror. I. Experimental test of the first order properties
Authors: Crewe  , Ruan  , Korda  , Tsai
Published: March 2003

When a uniform magnetic field is superimposed on a uniform electrostatic field, the combination can act as a magnetically focused mirror. This mirror is predicted to have aberrations of opposite sign to those of a magnetic lens and may therefore be useful as a corrector. We have built an electron optical system to test these ideas. The results are presented in two papers. This first paper describes the general design and the results of the measurements of the first order properties. The second paper (Tsai, F., J. Microsc. 197 (2000) 118–135) will describe the measurements of the aberration properties.
Unsupervised approval criteria for automated EBSP investigation of deformed metals
Authors: Godfrey  , Lassen N. C. Krieger
Published: March 2003

Unsupervised approval criteria have been investigated for orientations gathered from cold deformed samples (medium to high strain range) using the electron backscattering pattern technique. For such samples, the dislocation cell‐size is on the order of the available step‐size and pattern quality is generally low. Approval criteria for assessing the validity of measured orientations under these conditions were determined using, as a calibration, channel die cold deformed single crystals of stable orientations. In all cases, approval criteria based on an indexing confidence measure are found to be preferable. Different criteria are suggested, depending on whether the orientation data are subsequently to be used for texture analysis, or for a misorientation angle‐based analysis. The latter is illustrated by an investigation of the number of deformation generated high angle boundaries introduced during a 90% cold reduction of a polycrystalline sample.
Images of absolute retardance L.Δn, using the rotating polariser method
Authors: Geday  , Kaminsky  , Lewis  , Glazer
Published: March 2003

Modulation techniques for measuring changes in optical birefringence, such as the rotating‐polariser method (Wood & Glazer, 1980, J. Appl. Crystallogr. 13, 217), allow one to determine |sin δ|, δ = 2πLΔn/λ, Δn= double refraction, L = light path and λ = wavelength. However, they generally suffer from not providing absolute values of the optical retardance or are limited to relatively low retardance values. In addition, knowledge of the absolute phase is required when establishing the correct values of optical orientation information. In this paper, it is shown how the phase δ, and thus optical retardance, can be extracted from combining measurements of |sin δ| at different wavelengths. The new approach works on each single point of a 2‐D picture without the need to correlate with neighbouring points. There is virtually no limit to the retardance, and the computational efforts are small compared with other methods (e.g. Ajovalasit et al. 1998, J. Strain Analysis 33, 75). When used with imaging techniques, such as the rotating polariser method of Glazer, Lewis & Kaminsky 1996 (Proc. R. Soc. London SeriesA452, 2751) this process has the potential to identify automatically optically anisotropic substances under the microscope. The algorithm derived in this paper is valid not only for birefringence studies, but can be applied to all studies of interfering light waves.
Application of a laser scalpel to sectioning fragile tissues prior to optical sectioning microscopy and 3D reconstruction
Authors: Cookson M. J. , Entwistle A.
Published: March 2003

A method is described for the cutting of fragile material with a laser scalpel which minimizes damage to friable materials, making the interior of structures accessible for optical sectioning microscopy or for high resolution X‐ray microtomography followed by 3D reconstruction.
Penetration pathways of fluorescent dyes in human hair fibres investigated by scanning near‐field optical microscopy
Authors: Kelch A. , Wessel S. , Will T. , Hintze U. , Wepf R. , Wiesendanger R.
Published: March 2003

Thin cross‐sections of human hairs were investigated by scanning near‐field optical microscopy (SNOM) and confocal laser scanning microscopy (CLSM) after penetration of a fluorescent dye. The same samples were measured with both techniques to compare the observed structures. The images obtained from the two methods show nearly identical structures representing pathways of the dye molecules in hairs. The SNOM images provide a higher resolution than the CLSM images. Therefore, SNOM is believed to be a suitable method for investigations at a resolution of 100 nm on penetration pathways of fluorescent dyes such as the cell membrane complex pathway in cross‐sections of hairs.
Voronoi cells, fractal dimensions and fibre composites
Authors: Summerscales J. , Guild F. J. , Pearce N. R. L. , Russell P. M.
Published: March 2003

The use of fibre‐reinforced polymer matrix composite materials is growing at a faster rate than the gross domestic product (GDP) in many countries. An improved understanding of their processing and mechanical behaviour would extend the potential applications of these materials. For unidirectional composites, it is predicted that localized absence of fibres is related to longitudinal compression failure. The use of woven reinforcements permits more effective manufacture than for unidirectional fibres. It has been demonstrated experimentally that compression strengths of woven composites are reduced when fibres are clustered. Summerscales predicted that clustering of fibres would increase the permeability of the reinforcement and hence expedite the processing of these materials. Commercial fabrics are available which employ this concept using flow‐enhancing bound tows. The net effect of clustering fibres is to enhance processability whilst reducing the mechanical properties.

The effects reported above were qualitative correlations. To improve the design tools for reinforcement fabrics we have sought to quantify the changes in the micro/meso‐structure of woven reinforcement fabrics. Gross differences in the appearance of laminate sections are apparent for different weave styles. The use of automated image analysis is essential for the quantification of subtle changes in fabric architecture. This paper considers Voronoi tessellation and fractal dimensions for the quantification of the microstructures of woven fibre‐reinforced composites. It reviews our studies in the last decade of the process‐property‐structure relationships for commercial and experimental fabric reinforcements in an attempt to resolve the processing vs. properties dilemma. A new flow‐enhancement concept has been developed which has a reduced impact on laminate mechanical properties.
Segmentation of nuclei and cells using membrane related protein markers
Authors: Ortiz De Solorzano C. , Malladi R. , Lelièvre S. A. , Lockett S. J.
Published: March 2003

Segmenting individual cell nuclei from microscope images normally involves volume labelling of the nuclei with a DNA stain. However, this method often fails when the nuclei are tightly clustered in the tissue, because there is little evidence from the images on where the borders of the nuclei are. In this paper we present a method which solves this limitation and furthermore enables segmentation of whole cells. Instead of using volume stains, we used stains that specifically label the surface of nuclei or cells: lamins for the nuclear envelope and alpha‐6 or beta‐1 integrins for the cellular surface. The segmentation is performed by identifying unique seeds for each nucleus/cell and expanding the boundaries of the seeds until they reach the limits of the nucleus/cell, as delimited by the lamin or integrin staining, using gradient‐curvature flow techniques. We tested the algorithm using computer‐generated objects to evaluate its robustness against noise and applied it to cells in culture and to tissue specimens. In all the cases that we present the algorithm gave accurate results.
Stereological length estimation using spherical probes
Authors: Mouton P. R. , Gokhale A. M. , Ward N. L. , West M. J.
Published: March 2003

Lineal structures in biological tissue support a wide variety of physiological functions, including membrane stabilization, vascular perfusion, and cell‐to‐cell communication. In 1953, Smith and Guttman demonstrated a stereological method to estimate the total length density (Lv) of linear objects based on random intersections with a two‐dimensional sampling probe. Several methods have been developed to ensure the required isotropy of object–probe intersections, including isotropic‐uniform‐random (IUR) sections, vertical‐uniform‐random (VUR) slices, and isotropic virtual planes. The disadvantages of these methods are the requirements for inconvenient section orientations (IUR, VUR) or complex counting rules at multiple focal planes (isotropic virtual planes). To overcome these limitations we report a convenient and straightforward approach to estimate Lv and total length, L, for linear objects on tissue sections cut at any arbitrary orientation. The approach presented here uses spherical probes that are inherently isotropic, combined with unbiased fractionator sampling, to demonstrate total L estimation for thin nerve fibres in dorsal hippocampus of the mouse brain.
Surface plasmon fluorescence microscopy: an analysis
Authors: Somekh M. G.
Published: March 2003

This paper examines the imaging performance of surface plasmon microscopes operating in the far field. Until recently the accepted view has been that the achievable lateral resolution with a surface plasmon imaging system is limited by propagation decay length of the surface plasmons rather than by diffraction. We show by simulation that the lateral resolution of a surface plasmon imaging system can be comparable to that of the best optical microscopes. We also show that new imaging modes such as two‐photon and also second harmonic surface plasmon microscopy are extremely promising imaging modes that may be expected to be powerful techniques for the analysis of surface structures.
Pituitary Expression of Protein Kinase C Isotypes During Early Development
Authors: Korytko Andrew I. , Fields Alan P. , Allshouse Lisa A. , Cuttler Leona
Published: March 2003

Protein kinase C (PKC) is a critical regulator of signal transduction and cell function in many tissues, including pituitary. Although PKC influences pituitary hormone secretion in adults, its role in determining characteristic perinatal patterns of hormone secretion and synthesis is not known, and the expression of major PKC isotypes in perinatal pituitary is poorly defined. We therefore determined the developmental, cell‐specific expression of the major PKC isotypes, using Western analysis and double label immunohistochemistry, in pituitaries of perinatal and mature rats. Expression of specific PKC isotypes was strikingly age‐dependent. Pituitary expression of PKC α was particularly high in neonates and declined significantly with age, with levels in adult rats approximately half those of neonates as assessed by Western analysis. Similarly, immunohistochemistry indicated that PKC α was less abundant in adult than in neonatal pituitaries; the most intensely staining cells of both age groups were identified as somatotrophs and gonadotrophs. In contrast to PKC α, pituitary expression of PKC ε increased approximately two‐fold with advancing age as assessed by Western analysis; this age‐dependent pattern was confirmed by immunohistochemistry. Perinatal pituitaries expressed PKC ε in some somatotrophs and in all gonadotrophs, whereas PKC ε expression was limited to gonadotrophs in the mature pituitary. Pituitary expression of PKC βII, δ, and ζ did not differ with age, and PKC γ was not detected in pituitaries of any age group. These results indicate that expression of PKC isotypes within the pituitary is developmentally regulated in a cell‐specific and isotype‐specific manner, and are consistent with the concept that PKC contributes to the regulation of pituitary function during early development.
Investigation Into the Regulation of the Circadian System by Dopamine and Melatonin in the Adult Siberian Hamster (Phodopus sungorus)
Authors: Duffield  , Hastings  , Ebling
Published: March 2003

Dopamine and melatonin have both been implicated in mediating maternal influences on the developing circadian system of altricial rodents. The aim of these studies was to investigate their role in the entrainment of the circadian system of the adult Siberian hamster (Phodopus sungorus). In‐situ hybridization revealed that D1‐dopamine receptor (D1‐R) mRNA was expressed in the adult suprachiasmatic nucleus (SCN) at levels comparable to neonates. As dopamine has been postulated to mimic photic stimulation during early development, experiment 1 compared the effects of a D1‐R agonist and a light pulse on free‐running wheel running rhythms in hamsters maintained in constant dim red light. A phase response curve to light was generated, revealing clear phase delays early in the subjective night, and large phase advances in the late subjective night. However, the D1‐R agonist (SKF 81297, 2 mg/kg, s.c.) did not produce consistent phase shifts at any circadian phase. Experiment 2 tested the ability of this dopaminergic agonist to modulate photic responses of the circadian system. Free‐running animals were pre‐treated with SKF 81297 (2 mg/kg, s.c.) 30 min before a 15 min light pulse given early or late in the subjective night. This agonist had no effect on the magnitude of phase shifts at either circadian time. In experiment 3, light pulses at CT13–15 induced expression of the immediate early gene c‐fos in the SCN, as assessed by immunocytochemistry for the protein product. In contrast, SKF 81297 (2 mg/kg, s.c.) at the same phase did not induce c‐fos in the SCN, despite marked c‐fos induction in the caudate‐putamen, nor did it affect photic induction of c‐fos in the SCN. To investigate whether dopamine might be involved in nonphotic regulation of the circadian system in adult hamsters, experiment 4 compared the response of free‐running hamsters to a series of injections of SKF 81297 (2 mg/kg, s.c.) or melatonin (1 mg/kg, s.c.), since melatonin receptor expression in the SCN also persists into adulthood. Animals were treated every 23.5 h for 6 days. The serial injections of melatonin produced cumulative phase advances of up to 3 h when delivered in late subjective day, but not when presented in late subjective night. Hamsters did not respond to SKF 81297 or vehicle treatment at either circadian phase. Moreover, pre‐treatment with the dopaminergic agonist did not affect the phase‐advancing effects of melatonin when both were given in the serial injection protocol. These results demonstrate clear phase‐dependent effects of light pulses and melatonin on circadian rhythms in Siberian hamsters, but suggest that D1‐Rs in the SCN no longer modulate photic or melatonin‐dependent entrainment pathways in the adult.
Diurnal Changes in the Expression of Genes Encoding for Arginine Vasotocin and Pituitary Pro‐opiomelanocortin in the Rainbow Trout (Oncorhynchus mykiss): Correlation with Changes in Plasma Hormones
Authors: Gilchriest  , Tipping  , Levy  , Baker
Published: March 2003

Using quantitative in‐situ hybridization, this study monitored diurnal changes in the abundance of the gene transcripts of two corticotropin‐releasing peptides, arginine vasotocin (AVT) and isotocin in hypothalamic neurones, and of pro‐opiomelanocortin (POMC) mRNA in the pituitary of the rainbow trout (Oncorhynchus mykiss). A significant diurnal pattern of gene expression was only displayed in the hypothalamus by the parvocellular AVT neurones of the preoptic nucleus. Abundance of AVT mRNA in these neurones was low at lights on (06.00 h), increased during the morning to reach a plateau of peak values between 14.00 h and 22.00 h, and then declined during the dark phase. This pattern was the inverse of that shown by plasma cortisol values. Changes in AVT transcript abundance are also considered in terms of the reported diurnal change in circulating AVT concentration. Pituitary and hypothalamic AVT peptide content did not change. Transcripts of both POMC genes (POMC‐A and POMC‐B) were monitored in pituitary corticotropes and melanotropes. Only POMC‐A mRNA was detected in corticotropes where it showed no diurnal change in abundance. Transcripts of both POMC genes were found in the melanotropes, although, judging from autoradiographic intensity, POMC‐A mRNA predominated. Both genes showed diurnal differences in their transcription with POMC‐A mRNA showing peak values at 10.00 h and a nadir at 02.00 h, while POMC‐B mRNA showed an inverse pattern. The results indicate that the two POMC genes can be independently regulated.
Effect of Intraseptal Vasotocin and Vasoactive Intestinal Polypeptide Infusions on Courtship Song and Aggression in the Male Zebra Finch (Taeniopygia guttata)
Authors: Goodson  , Adkins‐Regan
Published: March 2003

The present experiments were conducted to test the hypothesis that septal arginine vasotocin (AVT) and vasoactive intestinal polypeptide (VIP) modulate directed song (a courtship behaviour) and aggression in male zebra finches (Taeniopygia guttata). Subjects were surgically fitted with a guide cannula directed at the septum. Following recovery they were tested for aggression and directed song following infusions of AVT, its antagonist (anti‐vasopressin, AVP), and saline volume control. Infusion of the AVT antagonist significantly reduced all three aggressive behaviours measured (pecks, beak fences and chases); and AVT infusion significantly facilitated beak fencing. Vasoactive intestinal polypeptide treatment significantly reduced pecking. No treatment produced a change in directed song. Comparison with findings in mammals suggests that modulation of aggression by septal AVT (or AVP) is evolutionarily conserved in vertebrates, but modulation of aggression by VIP has not previously been reported for any vertebrate.
Detection of Melanocortin‐3 Receptor mRNA in Immature Rat Pituitary: FUnctional Relation to γ3‐MSH‐Induced Changes in Intracellular Ca2+ Concentration?
Authors: Lorsignol  , Vande Vijver  , Ramaekers  , Vankelecom  , Denef
Published: March 2003

We have previously shown that γ3‐MSH stimulates DNA replication in lactotrophs, somatotrophs and thyrotrophs of early postnatal rat pituitary in culture. Since the melanocortin‐3 (MC‐3) receptor is the only known receptor displaying high affinity for γ3‐MSH, the present study explored whether mRNA of the latter receptor is present in the pituitary and whether the receptor is functional. RT‐PCR of RNA extracts from 14‐day‐old rat pituitary revealed the presence of MC‐3 receptor mRNA in both the anterior and the neurointermediate lobe. The identity of the amplified products was confirmed by sequence analysis. Dispersed cells of 14‐day‐old female rats (24 h in culture) were exposed to γ3‐MSH, and changes in intracellular free calcium levels ([Ca2+]i) were assessed by means of fluo‐3 video imaging. γ3‐MSH evoked a rapid and maintained oscillating [Ca2+]i increase in 5%, 10% and 15% of the cells at a dose of 0.1, 1 and 10 nM, respectively. The MC‐3/MC‐4 receptor antagonist Ac‐Nle4‐c[Asp5,(D‐Nal(2)7,Lys10]α‐MSH‐(4‐10)‐NH2 (SHU 9119) blocked the effect of γ3‐MSH in about 50% of the responsive cells. The present data suggest that the MC‐3 receptor is expressed in the rat pituitary but that this receptor mediates only half of the effects of its putative ligand, γ3‐MSH, on [Ca2+]i. Part of the effect of γ3‐MSH may be mediated by a MC‐3 receptor in a functional state different from the one studied previously in transfected cell lines or by a hitherto unidentified MC receptor.
Frequency Coding of Melatonin Signals Sufficient to Induce Testicular Growth in Photoregressed Siberian Hamsters
Authors: Prendergast  , Hugenberger
Published: March 2003

Integration of melatonin signals over the course of several weeks was studied in male Siberian hamsters maintained in a short day length (10 h light/day) from birth (d 0). On d 35, hamsters with undeveloped testes were housed in constant light and received 5 h s.c. infusions of melatonin (MEL; 100 ng/infusion) or saline (SAL) over the next 30 days. Infusions were provided either every day (30 MEL), every other day (1 MEL/1 OFF), for 2 consecutive days followed by 2 days with no infusion (2 MEL/2 OFF), for 5 consecutive days followed by 5 days with no infusion (5 MEL/5 OFF), for 15 consecutive days followed by 15 days with no infusion (15 MEL/15 OFF), or saline every day (30 SAL). On d 65 testes weights of 30 MEL hamsters were greater than those from 30 SAL, 1 MEL/1 OFF, or 2 MEL/2 OFF groups, but did not differ significantly from those of 5 MEL/5 OFF and 15 MEL/15 OFF animals. Serum FSH concentrations of 30 MEL hamsters exceeded those of all other groups which did not differ among each other. Between 15 and 30 consecutive daily melatonin signals are necessary and sufficient to initiate and sustain maximal gonadotropic activity in juvenile male hamsters kept in constant light. The neuroendocrine system responsive to melatonin does not bridge intervals of more than a day in any of several combinations and apparently is frequency‐coded for maximal responsiveness to daily signals.