Discrete Spot Research Articles

Plasmacytoma Mimicking Mediastinal Parathyroid Tumour in a Patient with Primary Hyperparathyroidism

The association of monoclonal gammopathies with primary hyperparathyroidism is well documented. Many case reports have documented the coexistence of primary hyperparathyroidism and multiple myeloma. The cause of this relationship is not known. We report the case of a 49-year-old gentleman who was treated for primary hyperparathyroidism. His initial preoperative nuclear scan had shown persistent activity and retention of tracer in the retrosternal region in addition to the discrete hot spot in the region of the lower pole of the left lobe of the thyroid. During surgery, the enlarged left inferior parathyroid gland was removed. In addition, the retrosternal area was also explored and found to be normal. Ten months later, he developed a mass in the region of the manubrium sternii which was proven to be a plasmacytoma. Were view the literature for similar cases and suggest hypotheses for a possible association. In conclusion, coexisting plasma cell dyscrasias including plasmacytoma should be considered in patients with primary hyperparathyroidism.

Comparing different approaches to model the rotational modulation of the Sun as a star

Context. The space missions MOST, COROT and Kepler are going to provide us with high-precision optical photometry of solar-like stars with time series extending from tens of days to several years. They can be modelled to obtain information on stellar magnetic activity by fitting the rotational modulation of the stellar flux produced by the brightness inhomogeneities associated with photospheric active regions. Aims. The variation of the total solar irradiance provides a good proxy for those photometric time series and can be used to test the performance of different spot modelling approaches. Methods. We test discrete spot models as well as maximum entropy and Tikhonov regularized spot models by comparing the reconstructed total sunspot area variation and longitudinal distributions of sunspot groups with those actually observed in the Sun along activity cycle 23. Appropriate statistical methods are introduced to measure model performance versus the timescale of variation. Results. The maximum entropy regularized spot models show the best agreement with solar observations reproducing the total sunspot area variation on time scales ranging from a few months to the activity cycle, although the model amplitudes are affected by systematic errors during the minimum and the maximum activity phases. The longitudinal distributions derived from the models compare well with the observed sunspot group distributions except during the minimum of activity, when faculae dominate the rotational modulation. The resolution in longitude attainable through the spot modelling is ~$60^{\circ}$, on average. Conclusions. The application of the maximum entropy modelling to solar analogues will provide us with a quite detailed picture of their photospheric magnetic activity that can be the base for comparative and evolutionary studies of solar-like magnetic activity and irradiance variations.

Identification of Isolates that Cause a Leaf Spot Disease of Brassicas as Xanthomonas campestris pv. raphani and Pathogenic and Genetic Comparison with Related Pathovars

ABSTRACT Twenty-five Xanthomonas isolates, including some isolates received as either X. campestris pv. armoraciae or pv. raphani, caused discrete leaf spot symptoms when spray-inoculated onto at least one Brassica oleracea cultivar. Twelve of these isolates and four other Xanthomonas isolates were spray- and pin-inoculated onto 21 different plant species/cultivars including horseradish (Armoracia rusticana), radish (Raphanus sativus), and tomato (Lycopersicon esculentum). The remaining 13 leaf spot isolates were spray-inoculated onto a subset of 10 plant species/cultivars. The leaf spot isolates were very aggressive on several Brassica spp., radish, and tomato causing leaf spots and dark sunken lesions on the middle vein, petiole, and stem. Based on the differential reactions of several Brassica spp. and radish cultivars, the leaf spot isolates were divided into three races, with races 1 and 3 predominating. A differential series was established to determine the race-type of isolates and a gene-for-gene model based on the interaction of two avirulence genes in the pathogen races and two matching resistance genes in the differential hosts is proposed. Repetitive-DNA polymerase chain reaction-based fingerprinting was used to assess the genetic diversity of the leaf spot isolates and isolates of closely related Xanthomonas pathovars. Although there was variability within each race, the leaf spot isolates were clustered separately from the X. campestris pv. campestris isolates. We propose that X. campestris isolates that cause a nonvascular leaf spot disease on Brassica spp. should be identified as pv. raphani and not pv. armoraciae. Race-type strains and a neopathotype strain for X. campestris pv. raphani are proposed.

A specialized processing body that is temporally and asymmetrically regulated during the cell cycle in Saccharomyces cerevisiae

RNase mitochondrial RNA processing (MRP) is an essential ribonucleoprotein endoribonuclease that functions in the degradation of specific mRNAs involved in cell cycle regulation. We have investigated where this processing event occurs and how it is regulated. As expected, results demonstrate that RNase MRP is predominantly localized in the nucleolus, where it processes ribosomal RNAs. However, after the initiation of mitosis, RNase MRP localizes throughout the entire nucleus and in a single discrete cytoplasmic spot that persists until the completion of telophase. Furthermore, this spot was asymmetrically found in daughter cells, where the RNase MRP substrate, CLB2 mRNA, localizes. Both the mitotic exit network and fourteen early anaphase release pathways are nonessential but important for the temporal changes in localization. Asymmetric localization was found to be dependent on the locasome. The evidence suggests that these spots are specialized processing bodies for the degradation of transcripts that are cell cycle regulated and daughter cell localized. We have called these TAM bodies for temporal asymmetric MRP bodies.

Detailed analysis of flame propagation during dust explosions by UV band observations

It is important to sufficiently understand the phenomena during the dust explosions in order to take appropriate measures preventing dust explosion accidents. However, at present basic knowledge on flame propagation mechanisms during dust explosions is not enough. In this study, therefore, the flame propagation mechanisms during dust explosions are examined by detailed analyses using a special observation at UV band. Small scale experiments were performed to analyze flame propagating processes in detail. In the experiments, the stearic acid was used as the combustible particle, suspended particles were ignited by an electric spark, and flame propagation through the combustible dust was observed by using a special observation system at UV band. The leading combustion zone is observed to consist of discrete burning blue spot flames by the observation using ordinary photograph system. It is questionable how the leading flame of such discrete structure propagates. In this study, high-speed video images at UV band through a band-pass filter were taken to detect OH emission from combustion reaction zone. Using this method, the propagating flame could be detected clearly and the flame propagation mechanism could be examined in detail. In the conditions performed in this study, discrete flame propagation was not observed and the leading flame was observed to propagate continuously. This result is of importance for understanding the flame propagation phenomena during dust explosion.

In situ observations on the mechanical stability of austenite in TRIP-steel

In-situ tensile deformation tests have been performed on a high Al TRIP steel (composition 0.26 wt. % Si, 1.5 wt. % Mn, and 1.8 wt. % Al) displaying the transformation-induced plasticity (TRIP) effect, while monitoring the phase transformation by means of X-ray microdiffraction in transmission geometry. Due to the small beam size (25 μm x 25 μm) every retained austenite grain appears as a discrete spot on the diffraction patterns. The diffraction patterns are treated like a powder pattern for different η-angles, with η representing the angle between the tensile direction and the normal direction of the diffracting {200}planes. The disappearance of austenite {200} reflections is analyzed during as a function of the imposed stress and orientation. Grains with η = 0 or 90° tend to transform to martensite more easily. A unique feature of this microdiffraction experiment is the possibility of detecting the average carbon concentration of the retained austenite as a function of stress. Direct proof has been obtained that austenite with a lower carbon content x c transforms at lower stress levels. The average X c increases from 1.0 to to 1.05 wt.%. This increase indicates a relatively narrow distribution of the carbon content.

The spatial resolution of LA-ICP-MS line scans across heterogeneous materials such as fish otoliths and zoned minerals

LA-ICP-MS line scans can provide equivalent or better information about the distribution of elements in heterogeneous solids than discrete spot analysis; and at much reduced time and cost. However, to do so, the spatial resolution for given instrumentation and operating conditions must be known. Here, we present a quantitative and reproducible method to do this that requires line scans across a sandwich of three glasses of varying certified concentrations of trace elements. To produce sufficient counting statistics, only Ca, Sr, Rb, and Pb were analysed. Raw data (counts per second) are reduced to “instantaneous concentration” and then filtered to produce concentration profiles that contain the same dimensions as the original data. The spatial resolution is empirically determined from these profiles by using a statistical “confidence” window. Spatial resolution is controlled by the magnitude of concentration gradients, the direction of concentration shifts, and the instrumental configuration and settings such as cell size and shape, and the speed of the scan. Spatial resolution is better for increasing concentration profiles than decreasing ones by a factor of 2. The relationship between the magnitude of the concentration gradient and the spatial resolution is linear. Therefore, once the range of concentration variation is known in any target, a minimum resolution can be determined from this linear relationship. The spatial resolutions of the three elements examined are observed to be the same suggesting that element specific ablation behaviours are not a significant control on spatial resolution. A Sr concentration profile from a natural sample (fish otolith) is generated, and the resolutions from the glass sandwich are applied. For the concentrations observed and the settings and hardware used, a minimum spatial resolution of 50 µm was calculated. Concentration variations at smaller scales can be detected but not quantified.

Mechanisms of flame propagation through suspended combustible particles

Phenomena of flame propagation through suspended combustible particles were investigated. Several recent experimental results were examined comprehensively; such as observation by photographs, flame propagation limits, temperature distribution, and iron current measurement. As combustible particles, 1-octadecanol and stearic acid were used. In the photographs, the leading combustion zone is observed to consist of discrete burning blue spot flames. However, the experimental investigations indicate that the real leading combustion zone must exist ahead of the visible leading combustion zone. The real leading combustion zone mainly consists of the burning of smaller particles and it governs the flame propagation behavior. Smaller particles play an important role in the flame propagation. The possible flame structures were also discussed.

In situ observations on the austenite stability in TRIP‐steel during tensile testing

In‐situ deformation tests have been performed on a steel displaying the transformation‐induced plasticity (TRIP) effect, while monitoring the phase transformation by means of X‐ray diffraction. A tensile stress is applied to 0.4 mm thick samples of this steel with mass contents of 0.26 % Si, 1.5 % Mn, and 1.8 % Al in a transmission geometry for a synchrotron‐radiation beam of 25 μm · 25 μm. On the diffraction patterns every grain appears as a discrete spot. The austenite {200} reflections are analysed during this investigation. The diffraction patterns are treated like a powder pattern for five different η‐angles, with η representing the angle between the tensile direction and the normal direction of the diffracting {200} planes. The results of the analysis show that η = 0° and η = 90° are the preferential orientations for the transformation to martensite. The Ludwigson and Burger model [9] is used to gain more information about the stress dependence of the deformation induced martensite formation. The microdiffraction patterns also reveal the changes in carbon concentration in austenite at each retained austenite fraction.

Analysis of mitochondrial antigens reveals inner membrane succinate dehydrogenase flavoprotein subunit as autoantigen to antibodies in anti-M7 sera

The role of mitochondrial proteins as antigens to antibodies of anti-M7 sera was analysed by flavin fluorescence, one- and two-dimensional Western blots and blue native gel electrophoresis. Flavin fluorescence of succinate dehydrogenase (SucDH, complex II of the respiratory chain) of rat liver inner mitochondrial membranes correlated with the immunoreactivity of a representative anti-M7 myocarditis serum. Antigens of isolated bovine heart mitochondria reacting with antibodies of myocarditis serum on two-dimensional Western blots were identified by MALDI-TOF and NanoESI mass spectrometry as myosin heavy chain beta and as dihydrolipoamide dehydrogenase of the mitochondrial 2-oxoacid dehydrogenase complexes. The SucDH-flavoprotein was not resolved as a discrete protein spot on two-dimensional polyacrylamide gels. However, separation of the rat liver inner mitochondrial membrane complexes by blue native gel electrophoresis followed by Western blotting, and Western blots of purified Escherichia coli SucDH complex revealed that anti-M7 sera contained antibodies directed against the SucDH-flavoprotein subunit.

Surface holography with LEED electrons

The present status of surface holography using low energy electron diffraction intensities is described. It is shown that diffuse intensity distributions appearing with disordered adsorption on a crystalline substrate can be interpreted in a holographic sense by the single adatom acting as a beam splitter for the primary electron beam. We demonstrate that intensities taken at many energies need to enter the reconstruction integral in order to retrieve well resolved atomic images. We also show that the method can be extended to use also discrete superstructure spot intensities instead of diffuse maps, so opening the field to ordered superstructures. The power and applicability of the method is discussed.

Ferrofluid structures: a magnetic dichroism study

Measurements have been made of the field strength and time dependence of the linear dichroism induced by magnetic fields in magnetite–based ferrofluid films. When combined with optical diffraction data, three characteristic regions, each indicative of the changing microstructure within the ferrofluid, were observed. The detection of dichroism even at low fields, indicated the presence of small, ‘primary’ linear aggregates. Above a threshold magnetic field strength, for which the dipolar energy of the system approximated to the thermal energy and, after a finite induction time, discrete optical spot diffraction patterns could also be detected which indicated a parallel alignment of independently spaced linear aggregates in the fluid. With further field strength and time increase, the diffraction pattern changed to strong, discrete lines, consistent with the aggregate filaments associating laterally so as to form the thicker condensed fibres often reported hitherto in the literature. Measurements in time indicated that this process involved discrete, reproducible formation times. Theoretical treatments of these processes are given and a model proposed for the structure of the fibres. As the underlying dichroism was constant, the primary aggregates maintained their integrity throughout, thereby accounting for the rapid disappearance of the diffraction pattern upon removal of the field. The need to appreciate the nature of these field and time–dependent associations within ferrofluid structures is important in their design and uses for magneto–mechanical devices.

Thermal analysis of a laser pulse for discrete spot surface transformation hardening

Conventional laser transformation hardening is achieved by scanning a laser beam over a surface to raise the temperature above the austenitizing temperature and allowing self quenching to form martensite. A new approach, developed at the National Research Council of Canada’s Integrated Manufacturing Technologies Institute, uses discrete pulses to create a series of hardened “spots.” Unfortunately, existing transformation hardening models do not apply to this case due to the traditional assumption of a scanning velocity. For this reason, new predictive tools must be developed. An analytical solution to the axisymmetric heat conduction under a Gaussian energy distribution is presented which can be used to calculate the temperature distribution from a short laser pulse. The method is also used to calculate the size of a transformation hardened spot under the incident energy of a stationary laser.

Holographic Image Reconstruction from Electron Diffraction Intensities of Ordered Superstructures

We report on a novel holographic reconstruction of well resolved atomic images from discrete spot intensities appearing in low-energy electron diffraction (LEED) from crystalline surfaces. This opens holographic LEED to the wide field of ordered systems giving access to rather complex surface structures.

Evaluation of Penicillium chrysogenum and its antifungal extracts as potential biological control agents against Botrytis fabae on faba beans

Antagonistic fungal isolates (AP1.S20, AP2.R16, Z1.S23 and AP2.R19), from root and soil samples of faba bean crops, inhibited mycelial growth of Botrytis fabae in vitro by up to 44·9%, producing clear inhibition zones. Spore suspensions of isolates AP2.R16, Z1.S23 and especially AP1.S20, significantly reduced the development of chocolate spot lesions on bean plants in the glasshouse. These isolates were identified as Penicillium chrysogenum. The cell free culture filtrate of AP1.S20 was screened in vitro for antifungal activity using four solvent extracts: ethyl acetate, chloroform, hexane and petroleum ether. The ethyl acetate fraction gave the largest inhibition of spore germination (95·7%), while the petroleum ether fraction significantly reduced germ-tube extension to 19% of the control. Thin layer chromatography of these solvent extracts displayed up to 15 discrete fractions from each solvent sample. On application of these to tlc plates, the germination of B. fabae conidia was inhibited at one discrete spot from each solvent extract, each with the same Rf value. Preliminary results using detached leaves showed that both the culture filtrate and a spore suspension of isolate AP1.S20 significantly reduced lesion development and lesion spread.

DNA adducts in cervical tissue of smokers and non-smokers

Cervical biopsy samples were taken from 40 women, aged between 31 and 72, undergoing hysterectomies. Twenty-two of the women were smokers, four were ex-smokers and 14 were non-smokers. DNA was isolated and analysed using 32P-postlabelling, after butanol extraction or nuclease P1 digestion enhancement of the adducts. Resolution of the adducts was by thin-layer chromatography on polyethyleneimine (PEI)-cellulose. The pattern of adducts seen was similar to smoking-related adducts detected in other tissues and consisted mainly of a diagonal zone of radioactivity. With the butanol extraction enrichment method, the levels of adducts in DNA from the 22 smokers ranged from 1.65 to 6.04 adducts/10 8 nucleotides (mean = 3.70, SD = 1.36), in DNA from non-smokers from 1.16 to 3.98 (ean = 2.04, SD = 0.77) and in samples from ex-smokers from 2.57 to 3.35 (mean = 2.86, SD = 0.37). The increase in adduct levels in smokers compared with non-smokers was highly significant (Mann-Whitney test p = 0.0005, two-tailed). When analysed by the nuclease P1 digestion enhancement method, total adduct levels in samples from smokers (mean = 2.95, SD = 1.77) were not significantly different ( p = 0.3, two-tailed) from levels in non-smokers (mean = 2.34, SD = 0.96). However, the level of a minor discrete adduct spot was significantly lower ( p = 0.02, two-tailed) in smokers (mean = 0.19, SD = 0.36) than in non-smokers (mean = 0.39, SD = 0.41). The results indicate that some of the DNA adducts detected in cervical epithelium correlate with tobacco smoking and support the hypothesis that smoking-related cervical cancer results from exposure to genotoxic components of cigarette smoke that become activated to DNA-binding products in this tissue.

Temporal behavior of cloud morphologies and motions in Saturn's atmosphere

Saturn's atmosphere displays a variety of temporal changes in its cloud morphology at synoptic and planetary scales. Hemispheric long‐term albedo variations, which are more pronounced at ultraviolet and blue wavelengths, have been well established and are apparently linked to the seasonal insolation cycle. Short‐term changes, of the order of months, have been observed in the spectral reflectivity of the belt/zone pattern mainly at mid‐latitudes. Some appear to be related to discrete spot activity, but for the majority of the changes, no such signs of spot activity were detected up to a resolution ∼2000 km. In particular, the “ribbon” structure at 45°N could have been affected by this activity and probably is a transient phenomenon. The polar belts at ∼65° north and south and those at 75° north (hexagon) and south show a long‐term stability in their location, perhaps for more than a century. The most prominent belts located in the Equator and the Equatorial Zone are persistent features of Saturn's globe; their main changes took place during the development of a rare, planetary‐scale disturbance known as Great White Spots. Only five such events have been observed at repetitive regular intervals of about one Saturn year since the first report in 1876, and at different latitudes from the equator to 60°N. They are probably convective in origin, with the seasonal heating of the upper atmosphere acting as a trigger mechanism. During its life cycle of 2–3 years, the disturbance shows turbulent planetary‐scale patterns of clouds that might be related to a wave dynamical phenomenon. Other distinct nonaxisymmetric cloud systems at synoptic scale are very scarce in Saturn's atmosphere. We observed new isolated features at several latitudes during 1990 and 1991. These spots, together with those available from historical records, are used as tracers for determining the latitude dependence and time variability of Saturn's zonal winds. The winds tend to exhibit a long‐term stability in their latitudinal positions and average wind speed, although some significant departures from the zonal mean Voyager profile have been detected during the development of the equatorial disturbance in 1990 and 1991.

Separation of alveolar macrophages and dendritic cells via autofluorescence: phenotypical and functional characterizatior

In a previous study we demonstrated that an increase of monocytes and dendritic cells (MDC) was In the current study, the bright autofluorescence of alveolar macrophages (AMs) was used to separate them efficiently from the MDC. Sorting of freshly isolated BAL cells resulted in a high-autofluorescent fraction, consisting predominantly of AMs, and a low-autofluorescent fraction containing the MDC, lymphocytes, and granulocytes. Thus, a clear separation between suppressive (AM) and stimulating (MDC) activity was obtained as shown in antigen-specific T cell responses. Flow cytometric parameters, density fractionation, and a series of ED monoclonal antibodies raised against rat macrophage antigens showed that both AMs and MDC were diverse populations. After overnight culture, more than 80% of an MDC population with a density range of 1.065-1.079 changed to a lower density (< 1.056) and morphologically developed into DCs with many processes. Concomitantly, monoclonal antibody ED1 expression changed from a granular pattern to a discrete juxtanuclear spot localization.

Role of the dorsolateral pontine nucleus in two components of optokinetic nystagmus (OKN).

The anatomical features of the dorsolateral pontine nucleus (DLPN) implicate a role of the nucleus in the generation of smooth-pursuit eye movements. The DLPN receives convergent inputs from a variety of parieto-occipital cortical visual areas and projects its fibers to the flocculus and vermal lobules VI and VII. In addition to cortical afferent fibers, the DLPN receives descending fibers from the nucleus of the optic tract which is indicated as the first subcortical optokinetic nystagmus (OKN) relay. DLPN units respond not only to a discrete visual spot but also to large-field OKN stimuli. On the basis of the above anatomical and physiological features, OKN was investigated in 2 alert monkeys whose DLPN was physiologically identified and into which reversible lidocaine was injected. The present findings showed that a rapid rise in OKN velocity was reduced in both monkeys, whose lesions included the uppermost rostral part of the nucleus in the one monkey and the entire nucleus in the other, whereas optokinetic after-nystagmus velocity was affected only in the latter. Taken together with physiological data, the DLPN possibly shares the domain of low selectivity speed selection in OKN and does not play a main role in the generation of OKN.

Monoclonal Antibody EBM11 (Anti-CD68) Discriminates between Dendritic Cells and Macrophages after Short-Term Culture

Identification of dendritic cells (DC) is usually done on the basis of their strong MHC class II expression, their typical dendritic morphology and their capacity to induce a strong proliferation of allogeneic T cells. However using these criteria DC can easily be confused with MHC class II positive macrophages (MΦ). In addition, the lack of an antibody directed to a specific DC marker greatly hampers the discrimination between DC and MΦ. In the present study it is shown that EBM11 (anti-CD68) is a marker specific for both human MΦ and DC but in a distinctive way. Human DC locate the EBM11 reactivity in a discrete juxtanuclear spot in contrast to MΦ which show EBM11 reactivity throughout the cytoplasm. This greatly improves identification of DC. Light and electron microscopy showed that the CD68 epitope is associated with (phago-)lysosomes. Remarkably the EBM11 spot was only seen in DC after short-term culture, which is an essential step in all classical DC enrichment procedures. Before culture, MΦ and DC were indistinguishable. These results show the close relationship between MΦ and DC and suggest an important role for the structure of the lysosomal apparatus in these antigen-presenting cells.