bluuebunny/crossref_metadata_2025 huggingface dataset:
Long‐lasting intestinal bleeding in an old patient with multiple mucosal vascular abnormalities and Glanzmann's thrombasthenia: 3‐year pharmacological management
Authors: Coppola A. , De Stefano V. , Tufano A. , Nardone G. , Amoriello A. , Cerbone A. M. , Di Minno G.
Published: March 2003

Abstract. Coppola A, De Stefano V, Tufano A, Nardone G, Amoriello A, Cerbone AM, Di Minno G (Centro di Coordinamento Regionale per le Emocoagulopatie; Università‘Federico II’, Napoli; A.O.R.N. ‘A. Cardarelli’, Napoli; Italy). Long‐lasting intestinal bleeding in an old patient with multiple mucosal vascular abnormalities and Glanzmann's thrombasthenia 3‐year pharmacological management (Case report). J Intern Med 2002; 252: 271–275.

A 75‐year‐old woman with Glanzmann's thrombasthenia was admitted because of persistent melaena. Endoscopic examination showed multiple angiodysplastic lesions, with active bleeding in small and large bowel. Electro‐coagulation of some lesions, octreotide, conjugated oestrogens and selective embolization of jejunal vessels did not change transfusion requirements. After 8 month‐transfusions, ethinylestradiol + norethisterone in association with octreotide was started, leading to no transfusion over the following 9 months. Bleeding recurred after withdrawing octreotide and substituting ethinylestradiol + norgestrel for the ethinylestradiol + norethisterone combination. Re‐introduction of octreotide did not improve bleeding; however, a reduction of transfusion requirement was observed when the ethinylestradiol + norethisterone pill was re‐administered. The association of octreotide and of an oestrogen–progesterone combination was helpful in the difficult management of recurrent bleeding in this patient with diffuse gastrointestinal vascular abnormalities and a severe condition predisposing to bleeding.
Recurrent deep venous thrombosis caused by congenital interruption of the inferior vena cava and heterozygous factor V Leiden mutation
Authors: Schneider J. G. , Eynatten M. V. , Dugi K. A. , Duex M. , Nawroth P. P.
Published: March 2003

Abstract. Schneider JG, Eynatten MV, Dugi KA, Duex M, Nawroth PP (Ruprecht‐Karls‐University of Heidelberg, Heidelberg, Germany). Recurrent deep venous thrombosis caused by congenital interruption of the inferior vena cava and heterozygous factor V Leiden mutation (Case report). J Intern Med 2002; 252: 276–280.

A case of a 44‐year‐old patient with recurrent deep venous thrombosis (DVT) caused by congenital dysgenesis of the inferior vena cava (IVC) in coincidence with heterozygous factor V Leiden mutation is presented. The IVC malformation was a fortuitous finding because the vascular malformation of the collateral draining thoracic veins were suspected to be a malignant mass in chest X‐ray. This vascular abnormality is a rare finding but recent epidemiological research suggests that there may be an association between the congenital absence of the IVC and DVT. In our case, the patient is even at higher risk combining the malformation probably affecting venous blood flow and the hypercoagulabilic state by heterozygous presence of the factor V Leidenmutation.
Cholesterol treatment forever? The first Scandinavian trial of cholesterol supplementation in the cholesterol‐synthesis defect Smith–Lemli–Opitz syndrome
Authors: Starck L. , Lövgren‐Sandblom A. , Björkhem I.
Published: March 2003

Objectives.  To investigate if exogenous cholesterol affects sterol turnover in the cholesterol‐synthesis defect Smith–Lemli–Opitz syndrome (SLOS) and if clinical effects justify long‐time supplementation. The SLOS is caused by a deficiency of the enzyme 7‐dehydrocholesterol‐7‐reductase with markedly reduced cholesterol levels and greatly increased levels of 7‐dehydrocholesterol (7‐DHC).

Design.  Treatment with dietary cholesterol in patients with SLOS in a case series study.

Setting.  All biochemical analyses were performed in one laboratory. The clinical follow‐up was carried out by one of the authors (LS), a paediatric neurologist.

Subjects.  Seven patients with biochemically verified SLOS have been diagnosed in Sweden and all of them are included in the study.

Interventions.  Six patients were treated for 0.5–6 years orally with cholesterol and the bile acid taurocholate and one patient was supplemented with cholesterol only.

Main outcome measures.  In addition to cholesterol, 7‐ and 8‐DHC, lathosterol was used as a marker of endogenous cholesterol synthesis and the patients were followed clinically. Nerve conduction velocities (NCV) were measured before treatment in all patients and a UVA‐light test was performed in one of them.

Results.  Lathosterol was initially increased by cholesterol supply in subjects with very low cholesterol levels with subsequent rise of 7‐ and 8‐DHC. Photosensitivity clinically improved in all, verified by UVA‐light testing in one. Progressive polyneuropathy improved, whilst stationary forms did not.

Conclusion.  Dietary cholesterol can up‐regulate sterol turnover in severely affected patients. Although some specific features are treatable and verifiable by objective methods, data supporting life‐long treatment dietary cholesterol in all SLO patients are still lacking.
Cardiac arrest related to coronary spasm in patients with variant angina: a three‐case study
Authors: Seniuk W. , Mularek‐Kubzdela T. , Grygier M. , Grajek S. , Cieśliński A.
Published: March 2003

We present three patients with variant angina pectoris and episodes of cardiac arrest. All of them had typical clinical symptoms, ST‐segment changes in electrocardiogram, and coronary artery spasm confirmed by arteriography. They were treated with high doses of calcium antagonists and nitrates. An automatic cardioverter‐defibrillator was implanted in the patient who developed ventricular fibrillation despite therapy with calcium antagonists. In another patient a DDD pacemaker was implanted because of high‐degree atrioventricular block.
A plasma glucose concentration below 2.5 mmol L−1 is not an appropriate criterion to end the 72‐h fast
Authors: Wiesli P. , Brändle M. , Schwegler B. , Lehmann R. , Spinas G. A. , Schmid C.
Published: March 2003

Abstract.  Wiesli P, Brändle M, Schwegler B, Lehmann R, Spinas GA, Schmid C (University Hospital, CH‐8091 Zurich, Switzerland). A plasma glucose concentration below 2.5 mmol L−1 is not an appropriate criterion to end the 72‐h fast. J Intern Med 2002; 252: 504–509.

Context.  The classical end‐point to terminate the 72‐h fast in a patient evaluated for a hypoglycaemic disorder is the occurrence of hypoglycaemic symptoms in association with a low plasma glucose level. However, neither the symptoms nor the plasma glucose level have been exactly defined.

Objective.  To determine whether a useful cut‐off plasma glucose concentration as criterion to end the prolonged fast in the absence of neuroglycopenic symptoms can be defined.

Design.  Single centre case–control study.

Setting.  Tertiary referral hospital in Switzerland.

Subjects.  The 72‐h fast was prospectively performed in 23 consecutive patients (17 women and six men) following a standardized protocol between July 1999 and January 2002. All patients were referred to our clinic for evaluation of suspected hypoglycaemia. The criterion to end the fast before 72 h was defined by the occurrence of symptoms or signs typical for neuroglycopenia irrespective of plasma glucose levels.

Main outcome measure.  Insulin levels and insulin to plasma glucose ratios in insulinoma patients and in individuals without insulin‐secreting tumours at termination of the fast and at plasma glucose levels ≤2.5 mmol L−1, prior to the occurrence of neuroglycopenic symptoms.

Results.  In seven patients, the fast was terminated before 72 h because they developed neuroglyco‐penic symptoms. Insulin‐secreting tumours were found and successfully removed in these seven patients. Sixteen individuals developed no neuroglycopenic symptoms throughout the 72‐h fast and an insulin‐secreting tumour could be excluded in these 16 patients. Five of these 16 individuals had plasma glucose levels ≤2.5 mmol L−1 during the 72‐h fast. Insulin levels and insulin to glucose ratios in insulinoma patients and healthy individuals overlapped during as well as at termination of the fast. Prior to the occurrence of neuroglycopenic symptoms and at venous plasma glucose ≤2.5 mmol L−1, insulin to plasma glucose ratios dropped in insulinoma patients to values within the normal range on several occasions.

Conclusions.  Terminating the fast at plasma glucose levels ≤2.5 mmol L−1 does not allow confirmation or exclusion of an insulin‐secreting tumour. Thus, the occurrence of symptoms or signs typical for neuroglycopenia is the prerequisite criterion to end the fast before 72 h.
Is low birth weight a risk factor for the development of diabetic nephropathy in patients with type 1 diabetes? A population‐based case–control study
Authors: Eshoj O. , Vaag A. , Borch‐Johnsen K. , Feldt‐Rasmussen B. , Beck‐Nielsen H.
Published: March 2003

Abstract.  Eshoj O, Vaag A, Borch‐Johnsen K, Feldt‐Rasmussen B, Beck‐Nielsen H (Odense University Hospital, Odense, Hvidovre Hospital, Copenhagen, Steno Diabetes Centre, Gentofte, University of Copenhagen, Copenhagen, Denmark). Is low birth weight a risk factor for the development of diabetic nephropathy in patients with type 1 diabetes? A population‐based case–control study. J Intern Med 2002; 252: 524–528.

Objectives.  To investigate if low birth weight as a consequence of intrauterine malnutrition is a risk factor for the later development of diabetic nephropathy.

Design and subjects.  In a case–control set‐up a group of type 1 diabetic subjects with diabetic nephropathy (n = 51) and a matched control group with normal kidney function (n = 51) were compared. Diabetic nephropathy and normal kidney function were defined as urinary albumin excretion rate above 200 μg min−1 and below 20 μg min−1, respectively. The birth weights were all obtained from the midwives' original records.

Setting.  The patients were identified from a population‐based study of chronic diabetic complications in the Funen County, Denmark.

Main outcomes.  Birth weights according to the presence of diabetic nephropathy.

Results.  The median (10–90 percentile) birth weights were 3600 g (2960–4274) in the group with diabetic nephropathy and 3600 g (2880–4220) in the group without nephropathy, P = 0.52. In the lower quartile of birth weights the median (10–90 percentile) birth weights were 3000 g (2780–3200) in the group with nephropathy versus 2850 g (2250–3175) in the group without nephropathy, P = 0.07. In the upper quartile the median (10–90 percentile) birth weights were 4225 g (4000–4741) in the nephropathy group and 4000 g in the group without nephropathy, P = 0.13. We found no significant correlation between birth weights and log urinary albumin excretion rate (r = 0.148, P = 0.14) and no difference in the number of patients with nephropathy in the lower versus upper quartiles of birth weights.

Conclusion.  We found no evidence of low birth weight as a risk factor for the development of diabetic nephropathy.
Inflammatory bowel disease: new insights into pathogenesis and treatment
Authors: Ardizzone S. , Porro G. Bianchi
Published: March 2003

Abstract. Ardizzone S, Bianchi Porro G (‘L. Sacco’ University Hospital, Milan, Italy). Inflammatory bowel disease: new insights into pathogenesis and treatment (Review).J Intern Med2002;252:475–496.

Despite all the advances in our understanding of the pathophysiology of inflammatory bowel disease (IBD), we do not know the cause. Some of the most recently available data have been discussed here and yet it is now becoming increasingly accepted that immunogenetics play an important role in the predisposition, modulation, and perpetuation of IBD. The mucosal immune system is the central effector of intestinal inflammation and injury, with cytokines playing a central role in modulating inflammation. The role of intestinal milium, and enteric flora in particular, appears to be of greater significance than previously held. A review is made of the main areas of research exploring the mechanisms more intimately associated with the development of IBD, providing advances in the agents currently used, and identifying a host of new therapeutic agents potentially interacting with or interrupting specific targets in the genesis of IBD.
Risk factors for coronary heart disease in 55‐ and 35‐year‐old men and women in Sweden and Estonia
Authors: Johansson J. , Viigimaa M. , Jensen‐Urstad M. , Krakau I. , Hansson L.‐O.
Published: March 2003

Abstract.  Johansson J, Viigimaa M, Jensen‐Urstad M, Krakau I I, Hansson L‐O (Karolinska Hospital, Stockholm, Sweden, Tartu University Hospital, Tartu, Estonia). Risk factors for coronary heart disease in 55‐ and 35‐year‐old men and women in Sweden and Estonia. J Intern Med 2002; 252:551–560.

Objective.  To illustrate the geographical West‐to‐East division of coronary heart disease (CHD) by comparing a population from Sweden, that represents a Western country to a population from Estonia, that represents an Eastern country. Estonia has an approximately 2–4‐fold higher CHD prevalence for 55‐year‐old women and men, respectively, than Sweden.

Design.  Randomized screening of 35‐ and 55‐year‐old men and women in Sollentuna county, Sweden and Tartu county, Estonia. Eight hundred subjects, 100 from each cohort, were invited to participate in the study, 272 Swedes and 277 Estonians participated.

Setting.  Preventive cardiology, administered by a primary health care centre at the Karolinska Hospital, Sweden and a cardiology centre at Tartu University Hospital, Estonia.

Main outcome measures.  The CHD risk factors (smoking, blood pressure, concentrations of lipoproteins, fibrinogen, and glucose) and certain environmental factors and attitudes related to CHD risk by questionnaires (fat‐type and alcohol ingestion, self‐assessed rating of CHD susceptibility).

Results.  Of the 55‐year‐old men, 57% smoked in Estonia and 20% smoked in Sweden. Similar, although less pronounced differences showing higher smoking prevalence, were seen for 35‐year‐old Estonian men and women, whilst for 55‐year‐old women, less than 20% smoked in either country. Estonian 55‐year‐old women had lower HDL cholesterol and higher LDL cholesterol serum concentrations than Swedish 55‐year‐old women. Estonians reportedly ate food containing more saturated fats than Swedes, as indicated by the scale‐score questionnaire. Estonians, relative to Swedes, rated their chance of developing CHD higher, and paradoxically, Estonians did to a much lesser degree believe that life style influences the risk of developing CHD.

Conclusions.  Elevated smoking prevalence is a striking difference between the Estonian and Swedish populations likely to explain the much higher CHD prevalence in Estonian men. The lower HDL cholesterol and higher LDL cholesterol in Estonian 55‐year‐old women may explain the higher CHD prevalence in Estonian women. Furthermore, the SWESTONIA CHD study (i.e. comparison between Sweden and Estonia) shows several environmental differences between the countries populations related to fat content in food, alcohol drinking patterns, and views on CHD risk and the importance of lifestyle intervention, that could contribute to the higher CHD prevalence in Estonia.
Asymptotic fractals in the context of grey‐scale images
Authors: Rigaut  , SchoËvaËrt‐Brossault  , Downs  , Landini
Published: March 2003

The estimation of the fractal dimension in the case of concave log–log Richardson–Mandelbrot plots can be obtained by using asymptotic fractal equations. We demonstrate here, under asymptotic fractal conditions, that additional derivations making use of the Minkowski dilation in grey‐scales lead to two asymptotes, one having a slope of 1 and the other a slope of DT − D + 1 (where DT is the topological dimension and D the fractal dimension). The resulting equation offers important advantages. It allows: (i) evaluation of scaling properties of a grey‐scale image; (ii) estimation of D without any iteration and (iii) generation of texture and heterogeneity models. We concentrate here on the first two possibilities. Images from cultured cells in studies of cytoskeleton intermediate filaments and kinetic deformability of endothelial cells were used as examples.
A symmetrical representation of the geometrical optics of the light microscope
Authors: Hammond C.
Published: March 2003

This paper provides an analysis of the functions of the optical components of the light microscope. Its novelty consists of a ray diagram in which the object is symmetrically related, either at a mirror plane or a centre of symmetry, to the optical components of the illuminating and imaging systems on either side of it.
Detection and quantitative assessment of image aberrations from single HRTEM lattice images
Authors: Stenkamp D
Published: March 2003

For utilizing the full capabilities of quantitative high‐resolution transmission electron microscopy in materials characterization, a precise knowledge of the various aberrations blurring the object information is essential. Here, we describe an extended approach to the detection and quantitative assessment of image aberrations from lattice images of crystal samples. The approach is based on a theoretical analysis of five‐beam lattice images in the presence of all relevant optical aberrations and for partial beam coherence. Compact analytical expressions for linear and nonlinear image Fourier coefficients as explicit functions of the aberration parameters are derived. In particular, a fundamental relationship between the occurrence of erroneous image symmetries and the simultaneous presence of optical misalignments and partial beam coherence is established. An image analysis procedure is proposed which allows for the detection of even‐ and odd‐order residual aberrations and for the quantitative determination of defocus, two‐fold astigmatism and axial coma if the three‐fold astigmatism is known. For coma‐free images, the three‐fold astigmatism can also be determined quantitatively. Moreover, the procedure allows for a reliable detection of crystal misalignment for images of wedge‐shaped crystal samples.
Mid‐infrared scanning near‐field optical microscope resolves 30 nm
Authors: Knoll B. , Keilmann F.
Published: March 2003

We explore the performance of a scanning near‐field infrared microscope, which works by scattering tightly focused CO2 laser radiation (λ = 10 μm) from the apex of a metallized atomic force microscope tip. The infrared images of test samples prove a spatial resolution of 30 nm and are free of topographical and inertial artefacts, thus they should be of great interest for practical applications. We also observe that the infrared contrast vanishes when the input beam polarization is orthogonal to the tip axis, in accordance with theoretical expectations for a mechanism of longitudinal field interaction.
Apertureless scanning near‐field magneto‐optical microscopy of magnetic multilayers
Authors: Aigouy L. , Grésillon S. , Lahrech A. , Boccara A. C. , Rivoal J. C. , Mathet V. , Chappert C. , Jamet J. P. , Ferré J.
Published: March 2003

We imaged magnetic domains in Pt/Co/Pt multilayers using an apertureless scanning near‐field optical microscope operating in reflection mode. As the magneto‐optical effects are weak for this kind of structure, a polarization modulation technique with a photoelastic modulator was used to reveal the contrast between magnetic domains. In the case of a Pt/Co/Pt trilayer structure, a strong improvement in lateral resolution is observed compared with far‐field magneto‐optical images and good sensitivity is achieved. In the case of a Pt/[Co/Pt]Pt multilayer structure, stripe domains of 200 nm width could be resolved, in good agreement with images obtained by magnetic force microscopy on the same structure.
Theoretical comparison of illumination and collection mode images of magneto‐optical dots
Authors: Vial A. , Van Labeke D.
Published: March 2003

We compare theoretical images of the same sample obtained with two different scanning near‐field optical microscopes. The sample is a two‐dimensional periodic array of magnetic sub‐micrometric dots. The magnetization is perpendicular to the sample plane (polar magnetization). The first configuration is a scanning tunnelling optical near‐field microscope (STOM) where the tip is used in the detection mode and the sample is illuminated by total internal reflection. The second configuration is an inverted STOM: the tip is used in the emission mode and the diffracted field is far‐field detected in one direction. We present the models used to describe the two configurations and then explain the main lines of the formalism used to calculate the diffracted fields by a magneto‐optical sample.
Magneto‐optical contrast in near‐field optics
Authors: Chen Y. , Kottler V. , Chappert C. , Essaidi N.
Published: March 2003

We propose a simple calculation of near‐field magneto‐optical (MO) images based on the beam propagation method. We calculate both Faraday rotation and circular dichroism contrasts of planar magnetic structures such as as‐grown thin films and ion‐irradiated samples. High‐contrast near‐field MO images are obtained, in good agreement with our experimental observations.
Stereological estimation of covariance using linear dipole probes
Authors: Reed  , Howard
Published: March 2003

Classical stereology is capable of quantifying the total amount or ‘density’ of a geometrical feature from sampled information, but gives no information about the local spatial arrangement of the feature. However, stereological methods also exist for quantifying the ‘local’ spatial architecture of a 3D microstructure from sampled information. These methods are capable of quantifying, in a statistical manner, the spatial interaction in a structure over a range of distances. One of the key quantities used in a second‐order analysis of a volumetric feature is the set covariance. Previous applications of covariance analysis have been ‘model‐based’ and relied upon computerized image analysis. In this paper we describe a new ‘design‐based’ manual method, known as linear dipole probes, that is suitable for estimating covariance from microscopic images. The approach is illustrated in practice on vertically sectioned lung tissue. We find that only relatively sparse sampling per animal is required to obtain estimates of covariance that have low inter‐animal variability.
Adhesion of microbes using 3‐aminopropyl triethoxy silane and specimen stabilisation techniques for analytical transmission electron microscopy
Authors: Taylor A. P. , Webb R. I. , Barry J. C. , Hosmer H. , Gould R. J. , Wood B. J.
Published: March 2003

A variety of adhesive support‐films were tested for their ability to adhere various biological specimens for transmission electron microscopy. Support films primed with 3‐amino‐propyl triethoxy silane (APTES), poly‐l‐lysine, carbon and ultraviolet‐B (UV‐B)‐irradiated carbon were tested for their ability to adhere a variety of biological specimens including axenic cultures of Bacillus subtilis and Escherichia coli and wild‐type magnetotactic bacteria. The effects of UV‐B irradiation on the support film in the presence of air and electrostatic charge on primer deposition were tested and the stability of adhered specimens on various surfaces was also compared. APTES‐primed UV‐B‐irradiated PioloformTM was consistently the best adhesive, especially for large cells, and when adhered specimens were UV‐B irradiated they became remarkably stable under an electron beam. This assisted the acquisition of in situ phase‐contrast lattice images from a variety of biominerals in magnetotactic bacteria, in particular metastable greigite magnetosomes. Washing tests indicated that specimens adhering to APTES‐primed UV‐B‐irradiated PioloformTM were covalently coupled. The electron beam stability was hypothesised to be the result of mechanical strengthening of the specimen and support film and the reduced electrical resistance in the specimen and support film due to their polymerization and covalent coupling.
Electric field depolarization in high aperture focusing with emphasis on annular apertures
Authors: Bahlmann K. , Hell S. W.
Published: March 2003

Electromagnetic focusing theory of light predicts that at high apertures field components arise that are polarized perpendicular to the initial polarization. Although vectorial depolarization has received considerable attention in focusing theory, no evidence has been presented as to its relevance in experiments. We measure the intensity of the perpendicularly orientated field in the focal region by utilizing monomolecular, fluorescent polydiacetylene layers whose transition dipoles are orientated in a single direction. For a 1.4 numerical aperture oil objective lens illuminated with linearly x‐polarized light, we find that the integral of the modulus squared of the y‐polarized focal field amounts to 1.5% of its x‐polarized counterpart. In particular, we show here that the depolarization increases when using annular apertures. Annuli formed by a central obstruction with a diameter of 89% of that of the entrance pupil raise the integral to 5.5%. This compares well with the value of 5.8% predicted by electromagnetic focusing theory; however, the depolarization is also due to imperfections connected with focusing by refraction. Besides fluorescence microscopy and single molecule spectroscopy, the measured intensity of the depolarized component in the focal plane is relevant to all forms of light spectroscopy combining strong focusing with polarization analysis.
Efficient estimation of number density in opaque material microstructures: the large‐area disector
Authors: Tewari A. , Gokhale A. M.
Published: March 2003

Unbiased and efficient estimation of number density of features in opaque material microstructures has been quite difficult. In this contribution a montage‐based efficient serial sectioning technique is presented as a practical solution for efficient estimation of number density in such microstructures. The new technique utilizes a combination of digital image analysis and unbiased disector sampling procedures.
Structural studies of pulsed‐laser deposited nanocomposite metal‐oxide films
Authors: Serna R. , Gonzalo J. , Suárez‐García A. , Afonso C. N. , Barnes J. P. , Petford‐Long A. K. , Doole R. C. , Hole D.
Published: March 2003

Pulsed laser deposition in vacuum has been used to develop metal‐oxide nanocomposite films with well controlled structural quality. Results for the copper–aluminium oxide (Cu:Al2O3) system are used to illustrate the main morphological and structural features of these films. High resolution transmission electron microscopy (TEM) analysis shows that the films consist of Cu nanocrystals with average dimensions that can be controlled between 2 nm and 10 nm embedded in an amorphous Al2O3 matrix. It is observed that the in‐plane shape of the nanocrystals evolves from circular to elongated, and the number of nanocrystals per unit area decreases as their size increases. This evolution is explained in terms of nucleation at the substrate surface and coalescence during the later stages of growth. The thermal stability of the films has been studied by in situ TEM annealing and no transformation could be observed up to about 800 °C when partial crystallization of the Al2O3 starts.
Epitaxial nucleation of crystallization at polymer–filler interfaces
Authors: Vesely D. , Ronca G.
Published: March 2003

In polymer composites the interaction between polymer matrix and filler particles often results in nucleation of spherulites. The principles of polymer crystal nucleation and spherulite growth are investigated using scanning transmission electron microscopy (STEM) and microdiffraction techniques in combination with polarized light microscopy. Simultaneous diffraction patterns from the interface of the filler and the polymer were obtained. Special precautions for successful recording of the diffraction patterns were used to overcome the rapid loss of polymer crystallinity, resulting from electron beam damage. Analysis of the diffraction patterns has shown that partial epitaxial correlation between the atomic periodicity of the particle surface and the molecular periodicity of polymer chains is always present when spherulites are nucleated. STEM images show that only large particles, with well developed facets (cleavage planes), are nucleating. The nucleating efficiency of the filler is therefore dependent on the size as well as on the crystallographic orientation of the facet. Small particles, or those with no suitable facets, do not affect the crystalline structure of the polymer. It is also shown that anisotropic polymer structures can be formed by inhomogeneous dispersion of nucleating filler particles.
Imaging of monolayers composed of palmitic acid and lung surfactant protein B
Authors: Flanders B. N. , Vickery S. A. , Dunn R. C.
Published: March 2003

Near‐field scanning optical microscopy and atomic force microscopy are used to probe the sub‐micrometre phase structure in palmitic acid monolayers containing the 25 peptide amino terminus of lung surfactant protein B (SP‐B1−25). Monolayers deposited onto mica substrates at a surface pressure of 15 mN m−1 exhibit a two‐phase coexistence across a broad range of SP‐B1−25 concentrations. Monolayers containing 5 wt.% SP‐B1−25 or less exhibit an expanse of liquid condensed phase in which elliptical liquid expanded (LE) domains with areas of approximately 25 µm2 coexist. By contrast, monolayers containing 20 wt.% SP‐B1−25 exhibit an expanse of liquid expanded phase in which circular liquid condensed domains coexist. The phase distribution dependence on SP‐B1−25 concentration suggests that the peptide induces disorder in the monolayer.
Immaterial tip concept by light confinement
Authors: Grosjean T. , Courjon D.
Published: March 2003

It is shown that the combination of TM polarized coherent evanescent light beams can lead to (x, y) confined light distributions. Moreover, owing to the evanescent nature of the interfering beams, the spatial distribution of the square modulus of the electric field does not vary versus the z‐distance. Such an energy distribution can be used as a virtual tip, allowing the scanning of a sample without any mechanical contact with it.
On the analysis of spatial binary images
Authors: Lang C. , Ohser J. , Hilfer R.
Published: March 2003

This paper deals with the analysis of spatial images taken from microscopically heterogeneous but macroscopically homogeneous microstructures. A new method is presented, which is strictly based on integral‐geometric formulae such as Crofton's intersection formulae and Hadwiger's recursive definition of the Euler number. By means of this approach the quermassdensities can be expressed as the inner products of two vectors where the first vector carries the ‘integrated local knowledge’ about the microstructure and the second vector depends on the lateral resolution of the image as well as the quadrature rules used in the discretization of the integral‐geometric formulae. As an example of application we consider the analysis of spatial microtomographic images obtained from natural sandstones.
GTG banding pattern on human metaphase chromosomes revealed by high resolution atomic‐force microscopy
Authors: Thalhammer S. , Koehler U. , Stark R. W. , Heckl W. M.
Published: March 2003

Surface topography of human metaphase chromosomes following GTG banding was examined using high resolution atomic force microscopy (AFM). Although using a completely different imaging mechanism, which is based on the mechanical interaction of a probe tip with the chromosome, the observed banding pattern is comparable to results from light microscopy and a karyotype of the AFM imaged metaphase spread can be generated. The AFM imaging process was performed on a normal 2n = 46, XX karyotype and on a 2n = 46, XY, t(2;15)(q23;q15) karyotype as an example of a translocation of chromosomal bands.
Direct observation of a Ti/Cu interface with atomic displacement under electron irradiation
Authors: Ohta S. , Sakaguchi N. , Shibayama T. , Takahashi H.
Published: March 2003

A Ti film was deposited onto a Cu substrate by means of a radio frequency magnetron sputtering method. Cross‐sectional thin foils for TEM observation were prepared using a focused ion beam. Electron irradiation was carried out using a high‐resolution high‐voltage electron microscope operated at 1.25 MV. The Cu/Ti interface of the foils was irradiated at 623 K. In‐situ observation images during electron irradiation were recorded by a CCD camera with a digital video cassette. The (020)Cu plane on the Cu/Ti interface preferentially moved towards the Ti film with irradiation. Composition analysis of the diffused region showed that its composition corresponded to Ti3Cu2.
A dual path programmable array microscope (PAM): simultaneous acquisition of conjugate and non‐conjugate images
Authors: Heintzmann R. , Hanley Q. S. , Arndt‐Jovin D. , Jovin T. M.
Published: March 2003

A programmable array microscope (PAM) incorporates a spatial light modulator (SLM) placed in the primary image plane of a widefield microscope, where it is used to define patterns of illumination and/or detection. We describe the characteristics of a special type of PAM collecting two images simultaneously. The conjugate image (Ic) is formed by light originating from the object plane and returning along the optical path of the illumination light. The non‐conjugate image (Inc) receives light from only those regions of the SLM that are not used for illuminating the sample. The dual‐signal PAM provides much more time‐efficient excitation than the confocal laser scanning microscope (CLSM) and greater utilization of the available emission light. It has superior noise characteristics in comparison to single‐sided instruments. The axial responses of the system under a variety of conditions were measured and the behaviour of the novel Inc image characterized. As in systems in which only Ic images are collected (Nipkow‐disc microscopes, and previously characterized PAMs), the axial response to thin fluorescent films showed a sharpening of the axial response as the unit cell of the repetitive patterns decreased in size.

The dual‐signal PAM can be adapted to a wide range of data analysis and collection strategies. We investigated systematically the effects of patterns and unit cell dimensions on the axial response. Sufficiently sparse patterns lead to an Ic image formed by the superposition of the many parallel beams, each of which is equivalent to the single scanning spot of a CLSM. The sectioning capabilities of the system, as given by its axial responses, were similar for a given scan pattern and for processed pseudorandom sequence (PRS) scans with the same size of the unit cell. For the PRS scans, optical sectioning was achieved by a subtraction of an Inc image or, alternatively, a scaled widefield image from the Ic image. Based on the comparative noise levels of the two methods, the non‐conjugate subtraction was significantly superior. A point spread function for Ic and Inc was simulated and properties of the optical transfer functions (OTFs) were compared. Simulations of the OTF in non‐conjugate imaging did not suffer from the missing cone problem, enabling a high quality deconvolution of the non‐conjugate side alone. We also investigated the properties of images obtained by subjecting the Ic and Inc data to a combined maximum likelihood deconvolution.
Studies of the microstructure of polymer‐modified bitumen emulsions using confocal laser scanning microscopy
Authors: Forbes A. , Haverkamp R. G. , Robertson T. , Bryant J. , Bearsley S.
Published: March 2003

Polymer‐modified bitumen emulsions present a safer and more environmentally friendly binder for enhancing the properties of roads. Cationic bitumen emulsion binders containing polymer latex were investigated using confocal laser scanning microscopy. The latex was incorporated into the bitumen emulsion by using four different addition methods and all emulsions were processed with a conventional colloid mill. The emulsion binder films were studied after evaporation of the emulsion aqueous phase. We show how the microstructure and distribution of the polymer varies within the bitumen binder depending on latex addition method, and that the microstructure of the binder remains intact when exposed to elevated temperature. It was found that a distinctly fine dispersion of polymer results when the polymer is blended into the bitumen before the emulsifying process (a monophase emulsion). In contrast, bi‐phase emulsion binders produced by either post‐adding the latex to the bitumen emulsion, or by adding the latex into the emulsifier solution phase before processing, or by comilling the latex with the bitumen, water and emulsifier all resulted in a network formation of bitumen particles surrounded by a continuous polymer film. The use of emulsified binders appears to result in a more evenly distributed polymer network compared to the use of hot polymer‐modified binders, and they therefore have greater potential for consistent binder cohesion strength, stone retention and therefore improved pavement performance.
Crystallographic orientation of ZrB2‐ZrC composites manufactured by the spark plasma sintering method
Authors: Shim S. H. , Niihara K. , Auh K. H. , Shim K. B.
Published: March 2003

The crystallographic grain orientation of ZrB2‐ZrC composites manufactured using a spark plasma sintering (SPS) method, a new sintering technique in development for poorly sinterable ceramic materials, was analysed by the scanning electron microscopy‐electron backscattered diffraction (SEM‐EBSD) method. Their crystallographic features have been compared with those of a conventionally sintered specimen using a pressureless sintering (PLS) method. In the composite sintered by PLS, (0001) planes of ZrB2 were orientated in the direction parallel to the specimen surface (RD) but (1010) and (2110) planes randomly orientated. In the case of SPS, (0001) planes of ZrB2 were orientated normal to the specimen surface (ND) and weakly to the RD. In both cases of PLS and SPS, ZrC grains had a randomly orientated grain structure. The distribution of grain boundary misorientation of PLS and SPS‐processed composites showed the same tendency that high‐angle boundaries were more prevalent than low‐angle boundaries. But in the case of ZrC grains in the SPS sample, the proportion of CSL boundaries with low sigma value (3, 5, 7, 9, 11) was relatively larger.
Is fast mapping good mapping? A review of the benefits of high‐speed orientation mapping using electron backscatter diffraction
Authors: Trimby P. , Day A. , Mehnert K. , Schmidt N.‐H.
Published: March 2003

Orientation mapping using automated electron backscatter diffraction (EBSD) is now a common technique for characterizing microstructures. Improvements in software and hardware have resulted in high‐speed mapping capabilities above 80 000 points h−1. For ‘routine’ microstructural analyses of materials such as steel and aluminium (e.g. texture and grain size measurements and high angle boundary characterization), high‐speed orientation mapping is an ideal approach with minimal penalty on the final statistics. However, for the accurate analysis of very low angle boundaries and for routine analyses of more difficult materials (e.g. most rock samples), we advocate a more patient approach to orientation mapping with an emphasis on data accuracy and reliability. It is important that the objectives of any EBSD analysis are carefully considered before starting – in this way the maximum potential of an EBSD system can be achieved.
Minimizing scanning electron microscope artefacts by filter design
Authors: Aronsson M. , Savborg Ö. , Borgefors G.
Published: March 2003

A new type of non‐linear filter for digital images has been developed. By using distance transforms we estimate the average point spread function for a set of fibre cross‐sectional images. Then a fast filter technique, based on lookup tables for distance layers, attenuates the uneven background response from the scanning electron microscope. Compared to the convolution‐based techniques that we tried, this approach caused less blurring effects on our fibre images and also made the background pixels more homogeneous. The only assumption we make is that we can roughly segment the background pixels by using a pixel‐wise classifier.

Although the assumption that the uneven background response can be described by a circular point spread function is only approximately true in the case discussed here, this method greatly attenuates the effect and provides a fast and general filtering method that can also be of use for other applications.
Rapid cryofixation of rabbit muscle fibres after a temperature jump
Authors: Bennett P. M. , Tsaturyan A. , Bershitsky S.
Published: March 2003

We describe a procedure whereby structural changes that occur in muscle fibres after a rapid temperature jump can be captured by cryofixation. In the thick filament from rabbit and other mammalian skeletal muscles there is a rapid transition from a non‐helical to a helical structure as the temperature is raised from 273 K towards physiological levels. This transition is accompanied by characteristic intensity changes in the X‐ray diffraction pattern of the muscle. In our experiments to capture these changes, single fibres of glycerinated psoas muscle were subjected to a Joule temperature jump of 15–30 K from ~278 K in air. We have developed a freezing method using a modified Gatan cryosnapper in which a pair of liquid nitrogen‐cooled copper jaws were projected under pressure and closed on the fibre between 50 and 100 ms after the temperature jump. The frozen fibres were freeze‐substituted and embedded for electron microscopy. Transverse and longitudinal sections of relaxed ‘cold’ (~278 K) and temperature‐jumped fibres as well as rigor fibres were obtained. Fourier transforms of the images from the three preparations showed differences in the relative intensities of the reflections from the hexagonal filament lattice and in those of the helix‐based layer lines, similar to the differences seen by X‐ray diffraction. We conclude that we have preserved the ‘hot’ structure and that cryofixation is sufficiently fast to prevent the transition back to the ‘cold’ state.
Embedding in Spurr's resin is a good choice for immunolabelling after freeze drying as shown with chemically unfixed dendritic cells
Authors: Spehner D. , Drillien R. , Proamer F. , Hanau D. , Edelmann L.
Published: March 2003

Immunocytochemical reactions on biological specimens depend on many factors, the most crucial one being the maintenance of antigenicity. Antigens are vulnerable at each stage during preparation for electron microscopy. One of the least traumatic methods of preparing biological tissues for post‐embedding immunolabelling includes the following steps: (1) physical stabilization of the native biological material by rapid freezing (cryofixation) and keeping the immobilized biological sample at low temperature, thereby avoiding any movements of water, ions and macromolecules; (2) dehydrating the frozen biological material by freeze‐drying at low temperature; (3) embedding of the dehydrated specimen. Here we show that embedding of chemically unfixed dendritic cells in Spurr's resin after cryofixation and freeze‐drying enables the conservation of fine ultrastructure without cell distortion or shrinkage. Furthermore, we demonstrate the feasibility of protein localization in ultrathin sections by immunolabelling of the major histocompatibility class II molecules.
Effect of Short Photoperiods on the in vitro GnRH Release by Hypothalamic Explants in Intact and Castrated Male Syrian Hamsters: Relation to Testicular Regression and Recrudescence
Authors: Caillol  , Rossano  , Martinet
Published: March 2003

Prolonged exposure of adult Syrian hamsters to short days decreases LH and FSH circulating levels within 2–4 weeks, then induces testicular regression. After 18 weeks of short days, the testis size and gonadotropin levels increase spontaneously. This study investigated whether these phases of photosensitivity and photorefractoriness corresponded to variations of in vitro GnRH release. Male hamsters were either kept under long days (LD 16:8) or transferred to short days (SD 6:18) and sacrificed from 2–26 weeks after transfer. To separate the effects of testis feedback from a possible direct photoperiodic drive on the hypothalamus, males were bilaterally castrated, kept under LD or transferred to SD, and sacrificed from 2–14 weeks after transfer. Hypothalamic explants were incubated in a saline buffer for three periods of 15 min and exposed to KCl (60 mM) for 15 min. The return to basal values was followed for six periods of 15 min, then the explants were stimulated with copper complexed equimolarly with histidine (Cu/His, 200 μM) and prostaglandin E2 (PGE2, 10 μM). At the end of the incubation period, the concentration of GnRH remaining in the explants was measured. In intact males, GnRH release in vitro increased significantly between 2 and 4 weeks after transfer to short days; it returned to values similar to LD ones between 6 and 12 weeks, during the phase of testis involution. At the beginning of photorefractoriness (SD 14–18), it increased transiently and returned to values similar to LD ones from SD 20, during the testis spontaneous recrudescence. After castration, the in vitro GnRH release decreased significantly under LD and SD. The transfer of castrated hamsters to SD resulted in transient increases of GnRH release (SD 4, 8 and 14), and in a progressive loss of the explant’s ability to release GnRH in vitro. These results showed a photoperiodic regulation of in vitro GnRH release and a testis feedback effect on this release. They demonstrated an inverse relationship between the readily releasable pool of GnRH and the circulating levels of gonadotrophins at the beginning of photosensitive and photorefractory phases and after castration.
Sexually Dimorphic Interaction of Insulin‐Like Growth Factor (IGF)‐1 and Sex Steriods in Lactotrophs
Authors: Chowen Julie A. , González‐Parra Silvia , García‐Segura Luis Miguel , Argente Jesús
Published: March 2003

Anterior pituitary hormone secretion is sexually dimorphic due partially to gender differences in the postpubertal hormone environment; however, differences in the pituitary’s responsiveness to these signals may also play a role. We have used simple and double in situ hybridization to determine whether lactotrophs and somatotrophs from male and female rats respond differently in vitro to growth hormone‐releasing hormone (GHRH), somatostatin (SS) or insulin‐like growth factor (IGF)‐I and whether sex steroids modulate these responses. Cultures were treated with either 17β‐estradiol (E; 10−9M), testosterone (T; 10−7 M), dihydrotestosterone (DHT; 10−7 M) or vehicle in combination with either GHRH (10−7 M), SS (10−7 M), IGF‐I (10−7 M) or vehicle. Basal mRNA levels of GH, prolactin (PRL) and pituitary transcription factor‐1 (Pit‐1) did not differ between the sexes. The responses to peptide hormones alone were similar between the sexes, but not in the presence of gonadal steroids. In females, DHT reduced and E increased the stimulatory effect of GHRH and inhibitory effect of SS on GH mRNA levels (two‐way
ANOVA: P<0.05), while having no effect in males. An additive effect of E and GHRH on PRL mRNA levels was seen only in males. The E induced rise in PRL mRNA levels was completely inhibited by SS in females, but only partially so in males (two‐way
ANOVA: P<0.001). IGF‐I inhibited the E induced rise in PRL and lactotroph Pit‐1 mRNA levels only in females. These results suggest that sex steroids modulate the pituitary’s response to hypothalamic and circulating factors differently in males and females and that this may play a role in generating the sexually dimorphic patterns of pituitary hormone secretion.