Origin of the pattern and chronology of chromosome replication in vertebrates.
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Animals↗
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Striate and extra-striate origins of pattern-related visual evoked potential (VEP) components.
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Journal Article↗
Expression pattern and cellular origin of cytokines in the normal and Toxoplasma gondii-infected murine brain.
In the normal brain, low levels of cytokines are observed, whereas inflammatory disorders of the central nervous system are characterized by an up-regulation of cytokine production. The cellular sources for cytokines in the central nervous system are largely undefined. In the present study, we have analyzed intracerebral cytokine production in normal and Toxoplasma gondii-infected mice using immunohistochemistry, in situ hybridization, flow cytometry of brain-derived leukocytes, and reverse transcriptase polymerase chain reaction detection in various subpopulations of inflammatory cells. In the normal brain, neurons and choroid plexus epithelia expressed interleukin (IL)-1 beta and IL-10. Microglia/macrophages produced IL-1 beta, IL-10, and tumor necrosis factor-alpha In Toxoplasma encephalitis, these cell types exhibited increased levels of the respective cytokines. In addition, microglia/macrophages showed a de novo expression of inducible nitric oxide synthase. CD4+ and CD8+ T cells, which were recruited to the brain, produced IL-2, IL-10, tumor necrosis factor-alpha, and interferon-gamma. IL-4 was exclusively detectable in CD4+ T cells, whereas CD8+ T cells showed expression of IL-1 beta. As chronic Toxoplasma encephalitis was not associated with neuronal degeneration and an up-regulation of neurotrophic factors, some cytokines may also exert neurotrophic and/or neuroprotective properties.
Animals↗
[Determination of geographical origins of Chinese medical herbs by NIR and pattern recognition].
Geographical origin of medical herbs is an important factor of the quality of many traditional Chinese herbal medicines. The objective of the present study is to investigate whether NIR spectroscopy coupled with pattern recognition techniques could effectively discriminate geographical origins of medical herbs. Nearest neighbor method (NNM) and a SVM-based multiclass classifier were employed to discriminate 269 Angelicae Dahuricae Radix (ADR) samples from 4 provinces and 380 Salviae Miltiorrhizae Radix (SMR) samples from 6 provinces in China. The multiclass classifier achieves leave-one-out cross-validation accuracy of 99% for (ADR) and 95% (SMR). This classification scheme can be a highly accurate approach to the rapid and nondestructive discrimination of medical herbs of different origins.
China↗
Sequential fragmentation: the origin of columnar quasihexagonal patterns.
We present a model that explains the origin and predicts the statistical properties of columnar quasihexagonal crack patterns, as observed in the columnar jointing of basaltic lava flows. Induced by temperature gradients during cooling, irregular fractures appear at the surface of the material. At later times fractures penetrate into the material, and tend to form polygonal patterns. We show that this ordering can be described as a tendency to minimize an energy functional. Atomistic simulations confirm this interpretation. Numerical simulations based on a phenomenological implementation of this principle generate patterns that have remarkably good statistical agreement with real ones.
Journal Article↗
An approach to construct simplified measures of dietary patterns from exploratory factor analysis.
Exploratory factor analysis might work well in elucidating the major dietary patterns prevailing in specific study populations. However, patterns extracted in one study population and their associations with disease risk cannot be reproduced with this data-specific method in other study populations. To construct less population-dependent pattern variables of similar content as original exploratory patterns, we proposed to derive so-called simplified pattern variables. They represent the sum of the unweighted standardised food variables which loaded high at the pattern of interest. Data from the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam study suggest that these simplified pattern variables might adequately approximate factor analysis-based dietary patterns. A simplified pattern variable based on the six highest loading food variables showed a correlation >0.95 with the originally derived factor score, which consisted of forty-seven food variables. Moreover, simplified pattern variables might adequately approximate patterns across different study populations. A simplified pattern variable showed similar factor loadings, ranging from 0.34 to 0.52, as well as similar associations with nutrient intake as a 'western' pattern originally reported from an US study population. These simplified pattern variables can subsequently be used to study pattern associations with disease risk, especially in multi-centre studies. It is therefore an approach that might overcome one of the most frequently claimed limitations of factor analyses applied in epidemiology: their non-comparable risk estimates.
Diet↗
Effect of thermal annealing and compression on the stability of microwrinkle patterns.
We find that annealing followed by uniaxial compression affects the microwrinkle pattern, which originally shows a complex stripe phase, and its stability to mechanical perturbation. We observe a characteristic quasi-biaxial stripe pattern after unloading compressive stress in contrast to the case without annealing, which shows the retrieval of the original pattern. Moreover, another loading-unloading cycle in a different direction induces a change in the modulated pattern, indicating that the pattern is no longer stable to mechanical perturbations.
Journal Article↗
Mating patterns of dermatophytes of diverse origin in India.
The mating patterns of Trichophyton mentagrophytes var. interdigitale (74 isolates) and the Microsporum gypseum complex (17 isolates) of diverse origin and T. rubrum (25 isolates) and T. tonsurans (10 isolates) of clinical origin were studied. The results of the study showed that the teleomorph of the Indian isolates of T. mentagrophytes belong to Arthroderma vanbreuseghemii, undetermined teleomorphs of T. mentagrophytes var. interdigitale (+) mating types, and undetermined teleomorphs of T. mentagrophytes var. interdigitale indeterminate mating types. All the isolates of T. rubrum and T. tonsurans were found to be of the (-) mating type.
Animals↗
New processing tools for weak and/or spatially overlapped macromolecular diffraction patterns.
Tools originally developed for the treatment of weak and/or spatially overlapped time-resolved Laue patterns were extended to improve the processing of difficult monochromatic data sets. The integration program PrOW allows deconvolution of spatially overlapped spots which are usually rejected by standard packages. By using dynamically adjusted profile-fitting areas, a carefully built library of reference spots and interpolation of reference profiles, this program also provides a more accurate evaluation of weak spots. In addition, by using Wilson statistics, it allows rejection of non-redundant strong outliers such as zingers, which otherwise may badly corrupt the data. A weighting method for optimizing structure-factor amplitude differences, based on Bayesian statistics and originally applied to low signal-to-noise ratio time-resolved Laue data, is also shown to significantly improve other types of subtle amplitude differences, such as anomalous differences.
Computer Graphics↗
[Thalidomide: Drug of horror and last resort. A review. Part 1: Origin, molecular structure and first pattern of use.].
Thalidomide was originally a hypnotic, sedative and anxiolytic drug that was first used in 1955. It was considered to have little toxicity and have smooth activity. Thalidomide was in fact poorly studied both in animals and for therapeutic purposes. It was nevertheless agressively advertised, and inter alia for use in pregnancy, and accordingly it was a much used drug. During the year 1961 it became evident that intake of thalidomide in therapeutic doses could result in severe peripheral neuritis and, when taken early in pregnancy, in horrendous damage to the fetus. Thalidomide was thus shortly afterwards generally removed from the market and its use prohibited. Nevertheless, interest rose a few years later to use thalidomide on other indications than before. This is the topic of Part 2 of this review as well as discussion of studies pertinent to the mechanisms of action of thalidomide.
English Abstract↗
Side-chains configurations in coiled coils revealed by the 5.15-A meridional reflection on hard alpha-keratin X-ray diffraction patterns.
The origin of the 5.15-A meridional reflection on hard alpha-keratin X-ray diffraction patterns is discussed in terms of side-chains conformations. We show it to reveal specific configurations of the side chains which are common to all two-stranded alpha-helical coiled coils. Combining literature data on crystallised coiled coil pieces and molecular dynamics results with our X-ray diffraction pattern simulations, we propose rules for the attribution of chi1 torsion angles for coiled coils involved in fibres whose structure cannot be resolved at atomic resolution: in a (a b c d e f g) heptad repeat, a and d residues, respectively, adopt mean t and g+ configurations, whereas statistical rules are given for the other residues.
Bacterial Proteins↗
Cells of origin, course, and termination patterns of the ventral, uncrossed component of the mature rat corticospinal tract.
The cells of origin, the course, and termination patterns of the ventral, uncrossed component of the rat corticospinal tract (CST) was investigated by using retrograde and anterograde tracing methods. Anterograde tracing with biotin dextran-amine (BDA) revealed the position and detailed morphology of CST fibers in the spinal cord. Cross sections on spinal levels C4, T8, and L4 showed labeled fibers in the ipsilateral ventral funiculus on all levels. Although ipsilateral ventral CST fibers run close to the midline in the cervical cord, they were found to disperse more in the ventromedial funiculus at lower spinal levels. To study the termination patterns of the ipsilateral ventral projection, a dorsal spinal cord hemisection was performed at level T8, severing the crossed dorsomedial and dorsolateral components but leaving ipsilateral ventral running fibers intact. These fibers were observed to have sometimes several collaterals with terminal arbors extending into different spinal segments, innervating mostly laminae III-VI. Structures closely resembling synaptic boutons were identified in these arbors. By retrograde tracing in animals with dorsal spinal cord hemisection, we found labeled cells equally distributed throughout the spinally projecting cortical areas corresponding to the level of tracer injection. Labeled cells were found in layer V. The diameter of the labeled cells was not significantly different from other spinally projecting cortical neurons. In summary, a neuroanatomically complete ipsilateral, ventral corticospinal projection down to low spinal levels was found. The large extension of the terminal arborizations in intermediate laminae of the spinal cord suggests a modulatory role of this CST component.
Animals↗
Wing pattern evolution and the origins of mimicry among North American admiral butterflies (Nymphalidae: Limenitis).
The evolution of wing pattern diversity in butterflies has emerged as a model system for understanding the origins and maintenance of adaptive phenotypic novelty. Admiral butterflies (genus Limenitis) are an attractive system for studying wing pattern diversity because mimicry is common among the North American species and hybrid zones occur wherever mimetic and non-mimetic wing pattern races meet. However, the utility of this system has been limited because the evolutionary relationships among these butterflies remain unclear. Here I present a robust species-level phylogeny of Limenitis based on 1911 bp of two mitochondrial genes (COI and COII) and 904 bp of EF1-alpha for all five of the Nearctic species/wing pattern races, the majority of the Palearctic species, and three outgroup genera; Athyma, Moduza (Limenitidini), and Neptis (Limenitidinae: Neptini). Maximum-likelihood and Bayesian analyses indicate that the North American species are a well-supported, monophyletic lineage that is most closely related to the widespread, Palearctic, Poplar admiral (L. populi). Within North America, the Viceroy (L. archippus) is the basal lineage while the relationships among the remaining species are not well resolved. A combined maximum-likelihood analysis, however, indicates that the two western North America species (L. lorquini and L. weidemeyerii) are sister taxa and closely related to the wing pattern subspecies of the polytypic Limenitis arthemis species complex. These results are consistent with (1) an ancestral host-shift to Salicaceae by the common ancestor of the Poplar admiral and the Nearctic admiral lineage, (2) a single colonization of the Nearctic, and (3) a subsequent radiation of the North American forms leading to at least three independent origins of mimicry.
Animals↗
[Breastfeeding patterns according to ethnic origin in two Well Child-Care Clinics in Beer Sheva and Ofakim].
OBJECTIVE: To determine breastfeeding patterns according to the ethnic origin of mothers of 2-year old babies in two Well Child-Care Clinics in Beer Sheva and Ofakim, Israel. METHODS: A cross-sectional study was performed including all mothers of 2-year old babies in two Well Child-Care Clinics in Beer Sheva and Ofakim. A structured interview was given to 132 mothers, which included demographic data and breast-feeding characteristics. RESULTS: A total of 106 mothers (80%) initiated and maintained breast-feeding. Mean duration of breast-feeding was 10.7 weeks (SD = 13). Women of North-African ethnicity were less likely to maintain breast-feeding (8.8 +/- 21.1) as compared to mothers of Iranian/Iraqi/Turkish descent (29.7 +/- 39.8) (p < 0.05). Mean duration of breast-feeding among mothers who worked out of their house was significantly longer as compared to housewives (7.7 +/- 14.5 vs. 16.9 +/- 29.3; p = 0.05). These women had a higher level of education as compared to the housewives (14.0 +/- 2.7 years vs. 11.6+/- 1.4 years; p < 0.01). Mothers of three children were less likely to maintain breast-feeding as compared to mothers of two children (8.8 +/- 10.6 weeks vs. 16.1 +/- 19.7 weeks; p < 0.05). CONCLUSIONS: Special efforts in the realm of education regarding the importance of breast-feeding should be focused on mothers of North-African descent, secular women, housewives and those having three or more children. Further prospective studies should investigate the efficacy of educational programs as well as support groups regarding breast-feeding.
Adult↗
The histone deacetylase inhibitor trichostatin A alters the pattern of DNA replication origin activity in human cells.
Eukaryotic chromatin structure limits the initiation of DNA replication spatially to chromosomal origin zones and temporally to the ordered firing of origins during S phase. Here, we show that the level of histone H4 acetylation correlates with the frequency of replication initiation as measured by the abundance of short nascent DNA strands within the human c-myc and lamin B2 origins, but less well with the frequency of initiation across the beta-globin locus. Treatment of HeLa cells with trichostatin A (TSA) reversibly increased the acetylation level of histone H4 globally and at these initiation sites. At all three origins, TSA treatment transiently promoted a more dispersive pattern of initiations, decreasing the abundance of nascent DNA at previously preferred initiation sites while increasing the nascent strand abundance at lower frequency genomic initiation sites. When cells arrested in late G1 were released into TSA, they completed S phase more rapidly than untreated cells, possibly due to the earlier initiation from late-firing origins, as exemplified by the beta-globin origin. Thus, TSA may modulate replication origin activity through its effects on chromatin structure, by changing the selection of initiation sites, and by advancing the time at which DNA synthesis can begin at some initiation sites.
Acetylation↗
Time-resolved electron paramagnetic resonance of photoinduced ion pairs in blends of polythiophene and fullerene derivatives.
Substituted polythiophene and triethylenglycolpyrrolidino-C(60) blends are examined by time-resolved electron paramagnetic resonance (TR-EPR) at different temperatures. TR-EPR spectra recorded on the microsecond time scale after a short laser pulse are assigned to polythiophene and fullerene radical ion pairs, generated by electron transfer from the excited state of polythiophene to fullerene. At low temperatures, TR-EPR spectra show polarized lines with an antiphase emission/absorption pattern. The origin of the polarization pattern is described in the frame of spin correlated radical pair theory, in which two unpaired electron spins (on radical cation and anion, respectively) interact through isotropic spin exchange and anisotropic dipolar interactions. The polarization pattern is accounted for assuming a singlet excited state as the precursor of the charge-separated state. Spectral simulations yield dipolar and spin exchange coupling constants between unpaired electrons of the radical ion pair. Their values correspond to a mean distance between opposite charges of 22 A. When the temperature is increased, the spectra gradually loose their antiphase character and eventually consist of a signal totally in emission. This behavior is explained by a polarization mechanism involving a spin-selective charge recombination (ST(-1) mixing). The polarization pattern at different temperatures is examined in detail, and its generating mechanism is discussed.
Journal Article↗
The role of self peptides in the allogeneic cross-reactivity of CTLs.
This study presents data relevant to understanding the molecular and structural basis for the cross-reactivity of many CTLs on multiple MHC targets. Five anti-H-2Kb alloreactive CTL clones derived from B6.C-H-2bm1 (bm1), B6.C-H-2bm8 (bm8), and B6.C-H-2bm11 (bm11) mice and a Sendai virus-specific H-2Kb-restricted CTL clone were studied. Self peptides extracted from Kb molecules were fractionated by HPLC and tested for their ability to be recognized on RMA/s (H-2b) cells by those clones. For each alloreactive clone, a single dominant peptide peak was found to sensitize target cells. In addition to recognizing peptides presented by the Kb molecule, the five alloreactive clones and the one Sendai virus-specific clone all showed cross-reactivities on a panel of Kbm mutant cells in a peptide-dependent manner. Two CTL clones, one alloreactive and one virus specific, cross-recognized Kbm targets by each responding to a unique self peptide in the context of the mutant MHC molecules. Our data underscore the prevalent idea that TCR-alpha beta have an inherent structural capability to react with several peptide/MHC structural patterns other than the original peptide/MHC pattern that might have been used to select that TCR. The high incidence of cross-reactivity seems to reflect a feature of the mechanism of positive selection in the thymus and the need for T cells in the repertoire to have an expanded capability for responding to a wide variety of foreign Ags.
Animals↗
Segmental specificity of chick sympathetic preganglionic projections is influenced by preganglionic neurons from neighboring spinal cord segments.
Sympathetic preganglionic neurons of the chick are located between the brachial and lumbosacral enlargements of the spinal cord. Their axons exit the spinal cord via their adjacent ventral roots and project rostrally or caudally along the sympathetic trunk to innervate sympathetic ganglia. The projections of sympathetic preganglionic neurons are segmentally specific. Neurons from the 16th cervical (C16) and the first thoracic (T1) spinal cord segments project predominantly in the rostral direction, whereas those from the fifth thoracic (T5) to the first lumbar (L1) spinal segments project predominantly in the caudal direction. Neurons from intervening spinal cord segments (T2-T4) project in rostral and caudal directions. In the present study, neural tube manipulations show that the direction of preganglionic projections is altered by both the elimination and addition of preganglionic neurons projecting into the sympathetic trunk from neighboring segments. The present study also compares the projections of preganglionic neurons from transplants of multiple neural tube segments with those from transplants of single neural tube segments reported in a previous study (Yip, 1987). In the previous study when single thoracic neural tube segments were transplanted to the cervical level, preganglionic neurons did not maintain their original projection patterns. The present study found that, when contiguous neighboring segments were transplanted to the cervical level, preganglionic neurons maintained projection patterns characteristic of their original segmental levels. These results indicate that the direction of preganglionic projections can be influenced by neurons from neighboring segments, suggesting that the formation of segmentally specific preganglionic projections during embryogenesis may involve the interactions of preganglionic neurons with those from neighboring spinal cord segments.
Adrenergic Fibers↗