Band Patterns (band + pattern)

Distribution by Scientific Domains

Selected Abstracts

Hunter-Schreger Band patterns in human tooth enamel

Christopher D. Lynch
Abstract Using light microscopy, we examined Hunter-Schreger Band (HSB) patterns on the axial and occlusal/incisal surfaces of 160 human teeth, sectioned in both the buccolingual and mesiodistal planes. We found regional variations in HSB packing densities (number of HSBs per mm of amelodentinal junction length) and patterns throughout the crown of each class of tooth (maxillary and mandibular: incisor, canine, premolar, and molar) examined. HSB packing densities were greatest in areas where functional and occlusal loads are greatest, such as the occlusal surfaces of posterior teeth and the incisal regions of incisors and canines. From this it is possible to infer that the behaviour of ameloblasts forming enamel prisms during amelogenesis is guided by genetic/evolutionary controls that act to increase the fracture and wear resistance of human tooth enamel. It is suggested that HSB packing densities and patterns are important in modern clinical dental treatments, such as the bonding of adhesive restorations to enamel, and in the development of conditions, such as abfraction and cracked tooth syndrome. [source]

Lyonization pattern of normal human nails

GENES TO CELLS, Issue 5 2008
Mariko Okada
To examine the X-inactivation patterns of normal human nails, we performed the human androgen receptor gene assay of DNA samples extracted separately from each finger and toe nail plates of nine female volunteers. The X-inactivation pattern of each nail was unique and constant for at least 2 years. The frequency of nails with one of the two X-chromosomes exclusively inactivated was 25.9%. In the nails composed of two types of cells with either one X-chromosome inactivated, the two cell types were distributed in patchy mosaics. These findings suggest that the composition of precursor cells of each nail is maintained at each site at least through several cycles of regeneration time, and that the nail plate has a longitudinal band pattern, each band consisting of cells with only one of the two X-chromosomes inactivated. Using the frequency of nails with one of two X-chromosomes exclusively inactivated, we estimated the number of progenitor cells that gave rise to the nail plate during development to be about 3, under the assumption that the process follows the binominal distribution model. A strong correlation observed among the big, index and little fingers, and among the corresponding toes suggests an interesting interpretation concerning their morphogenetic process. [source]

Response of methanogen populations to organic load increase during anaerobic digestion of olive mill wastewater

Aurora Rizzi
Abstract Process performances of an upflow anaerobic filter treating olive mill wastewater and the response of methanogenic Archaea to increasing volumetric organic load (VOL) were studied. At a VOL of 15 g chemical oxygen demand (COD) L,1 day,1, 90% of the influent COD was removed. Following a VOL increase from 6 to 15 g COD L,1 day,1, the polymerase chain reaction (PCR) titre of hydrogenotrophic Methanobacterium, determined by magnetic capture of the target DNA and group-specific PCR based on the 16S rRNA gene, decreased from 1011 to 108 cells g,1 sludge, while that of Methanomicrobiaceae and relatives increased from 104 to 106 cells g,1 sludge. Methanosaeta -like acetoclastic methanogens were less affected by VOL variation and dominated at high VOL with a 16S rRNA gene PCR titre of 109 cells g,1 sludge. Single-strand conformation polymorphism analysis of the PCR-amplified archaeal 16S rRNA gene showed a stable band pattern, indicating that VOL variation affected the methanogen PCR titre but not the archaeal community structure. Copyright © 2006 Society of Chemical Industry [source]

Identification of S -alleles using polymerase chain reaction-cleaved amplified polymorphic sequence of the S -locus receptor kinase in inbreeding lines of Brassica oleracea

PLANT BREEDING, Issue 3 2002
J. I. Park
Abstract Identification and DNA polymorphism of the S -locus receptor kinasegene (SRK) was analysed by pollen tube tests, polymerase chain reaction-cleaved amplified polymorphic sequence (PCR-CAPS) and nucleotide sequencing. SRK -specific primers that can distinguish class and class II S haplotypes amplified single DNA fragments of 900-1050 bp. The DNA fragments of 22 inbred lines amplified with a class SRK -specific primer pair determined seven types with HinfI and EcoRII. In addition, the DNA fragments of 17 inbred lines amplified with a class II SRK -specific primer pair determined three types with Hinf1. Nucleotide sequencing of the DNA fragments amplified from 10S haplotypes showed that exons of the 3,-end in SRK are highly conserved, and that there is much variation of the introns, which produced polymorphism of the band pattern in PCR-CAPS profiles. The S haplotypes of the plants were determined by restriction analysis of PCR products and agreed with results based on pollen tube growth tests. The PCR-CAPS analysis using specific primer pairs of SRK is considered to be useful for S allele identification in breeding programmes. [source]

Simple circuit to improve electric field homogeneity in contour-clamped homogeneous electric field chambers

José A. Herrera
Abstract We redesigned contour-clamped homogeneous electric field (CHEF) circuitry to eliminate crossover distortion, to set identical potentials at electrodes of each equipotential pair and to drive pairs with transistors in emitter follower stages. An equipotential pair comprised the two electrodes set at the same potential to provide electric field homogeneity inside of the hexagonal array. The new circuitry consisted of two identical circuits, each having a resistor ladder, diodes and transistors. Both circuits were interconnected by diodes that controlled the current flow to electrodes when the array was energized in the ,A' or ,B' direction of the electric field. The total number of transistors was two-thirds of the total number of electrodes. Average voltage deviation from potentials expected at electrodes to achieve a homogeneous electric field was 0.06 V, whereas 0.44 V was obtained with another circuit that used transistors in push-pull stages. The new voltage clamp unit is cheap, generated homogeneous electric field, and gave reproducible and undistorted DNA band patterns. [source]

Kinematic modelling of shear band localization using discrete finite elements

X. Wang
Abstract Modelling shear band is an important problem in analysing failure of earth structures in soil mechanics. Shear banding is the result of localization of deformation in soil masses. Most finite element schemes are unable to model discrete shear band formation and propagation due to the difficulties in modelling strain and displacement discontinuities. In this paper, a framework to generate shear band elements automatically and continuously is developed. The propagating shear band is modelled using discrete shear band elements by splitting the original finite element mesh. The location or orientation of the shear band is not predetermined in the original finite element mesh. Based on the elasto-perfect plasticity with an associated flow rule, empirical bifurcation and location criteria are proposed which make band propagation as realistic as possible. Using the Mohr,Coulomb material model, various results from numerical simulations of biaxial tests and passive earth pressure problems have shown that the proposed framework is able to display actual patterns of shear banding in geomaterials. In the numerical examples, the occurrence of multiple shear bands in biaxial test and in the passive earth pressure problem is confirmed by field and laboratory observations. The effects of mesh density and mesh alignment on the shear band patterns and limit loads are also investigated. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Assessment of genomic instability in breast cancer and uveal melanoma by random amplified polymorphic DNA analysis

Sarantos Papadopoulos
Abstract Some types of cancer have been associated with abnormal DNA fingerprinting. We used random amplified polymorphic DNA (RAPD) to generate fingerprints that detect genomic alterations in human breast cancer. Primers were designed by choosing sequences involved in the development of DNA mutations. Seventeen primers in 44 different combinations were used to screen a total of 6 breast cancer DNA/normal DNA pairs and 6 uveal melanoma DNA/normal DNA pairs. Forty-five percent of these combinations reliably detected quantitative differences in the breast cancer pairs, while only 18% of these combinations detected differences in the uveal melanoma pairs. Fourteen (32%) and 12 (27%) primers generated a smear or did not produce any band patterns in the first and second cases, respectively. Taking into account the ability of RAPD to screen the whole genome, our results suggest that the genomic damage in breast cancer is significantly higher than in uveal melanoma. Our study confirms other reports that the molecular karyotypes produced with random priming, called amplotypes, are very useful for assessing genomic damage in cancer. © 2002 Wiley-Liss, Inc. [source]

Phenotypic and genotypic characterization of reference strains of the genus Aspergillus

MYCOSES, Issue 3-4 2001
P.-M. Rath
Aspergillus; Genotypisierung; Biotypisierung; SDS-PAGE; RAPD Summary. Twenty-five culture collection strains from four Aspergillus species (A. fumigatus n = 8, A. flavus n = 8, A. niger n= 4, A. nidulans n = 5) were characterized by four methods: (i) determination of patterns in an assimilation assay; (ii) protein pattern of whole mycelial cell lysates in the sodium dodecyl sulphate (SDS)-polyacrylamide gel electrophoresis (PAGE); (iii) reactivity of a pool serum obtained from cystic fibrosis patients with mycelial lysates in the immunoblot; and (iv) random amplification of polymorphic DNA (RAPD) with eight primers having arbitrary or repetitive sequences. In the assimilation assay the A. fumigatus strains showed identical patterns in contrast to the strains of the species A. flavus, A. niger, and A. nidulans, which each showed four patterns. In the SDS-PAGE no differences in the band patterns in the A. fumigatus strains were found, in contrast to the A. flavus (three patterns), A. nidulans (five patterns) and A. niger strains (two patterns). The immunoblot patterns were characteristic for each species with bands at 62 and 17/18 kDa in the A. fumigatus strains, at 51 and 18 kDa in the A. flavus strains, at 51 kDa in the A. niger strains, and at 51, 40 and 17/18 kDa in the A. nidulans strains allowing, however, no intraspecies typing. In the RAPD assay four out of eight primers gave interpretable patterns with 3,20 bands. None of the primers showed sufficient discriminatory power when used alone. However, when combining the results of two of the primers (5,-GTA TTG CCC T-3, and 5,-GAT AGA TAG ATA GAT A-3,) all strains except two A. fumigatus strains could be clearly separated from each other. It is concluded that the the RAPD assay showed the most discriminatory power in all Aspergillus species investigated. In contrast to the phenotypically similar A. fumigatus strains, the strains of the species A. flavus, A. nidulans and A. niger differed in their phenotypic characteristics. The presented data of strains from international culture collections may serve as basis for interlaboratory standardization of typing methods. Zusammenfassung. Fünfundzwanzig Aspergillus -Stämme aus internationalen Stammsammlungen (A. fumigatus n = 8, A. flavus n = 8, A. niger n = 4, A. nidulans n = 5) wurden mit vier Methoden charakterisiert: (1) Reaktionsmuster in einem Assimilationstest (2) Proteinmuster von Ganzzell-Lysaten in der SDS-PAGE (3) Reaktionsmuster eines Poolserums von Patienten mit Mukoviszidose mit Zellextrakten im Immunoblot und (4) random amplification of polymorphic DNA (RAPD) mit acht Primern zufälliger oder repetitiver Sequenz. Im Assimilationstest zeigten die A. fumigatus -Stämme identische Muster, während die Stämme der Spezies A.flavus, A. niger und A. nidulans je vier Reaktionsmuster aufwiesen. In der SDS-PAGE wiesen die A. fumigatus -Stämme identische Muster auf, während die A. flavus -Stämme drei, die A. niger -Stämme zwei, und die A. nidulans -Stämme fünf verschiedene Muster zeigten. Im Immunoblot waren die Muster für jede Spezies charakteristisch mit Banden bei 62 kDa und 17/18 kDa bei A. fumigatus, bei 51 kDa und 18 kDa bei A. flavus, bei 51 kDa bei A. niger und bei 51, 40 und 17/18 kDa bei A. nidulans. Eine Intraspezies-Typisierung gelang jedoch nicht. In der RAPD ergaben vier der acht Primer interpretierbare Muster mit 3 bis 20 Banden. Keiner der Primer alleine zeigte eine ausreichende Diskriminationskapazität. Wurden die Resultate von zwei Primern (5,-GTA TTG CCC T-3, and 5,-GAT AGA TAG ATA GAT A-3,) kombiniert, konnten mit Ausnahme von zwei A. fumigatus -Stämmen alle Isolate voneinander abgegrenzt werden. Die Ergebnisse zeigen, daß die RAPD die größte Diskriminationskapazität aufweist. Im Gegensatz zu den phänotypisch ähnlichen A. fumigatus -Stämmen unterschieden sich die Stämme der Spezies A. flavus, A. nidulans und A. niger voneinander. Die gezeigten Daten von Stämmen internationaler Stammsammlungen können als Grundlage für die Standardisierung von Typisierungsmethoden dienen. [source]

Age-Related Mitochondrial DNA Mutations in the Human Larynx

Jose M. Manaligod MD
Abstract Objective To determine whether age-related mitochondrial DNA mutations occur in the human larynx. Study Design Genetic study of cadaveric larynx specimens. Methods Vocal fold mucosa, thyroarytenoid muscle, and cricoarytenoid joint tissue were harvested from 13 fresh postmortem larynges (age range, 2 d,82 y). DNA was extracted from each sample, and the polymerase chain reaction (PCR) was used to amplify a target DNA sequence resulting from the common age-associated, 4977,base-pair (bp) mitochondrial DNA deletion. PCR products were visualized by agarose gel electrophoresis. Automated sequencing determined the sequence of identified PCR products. Subjects Thirteen cadaveric larynges were obtained through the University of Kentucky Medical Center (Lexington, KY). Specimens from patients with a history of head and neck cancer, previous laryngeal trauma, or surgery were excluded. Results Strongly positive bands were identified in samples from three individuals. Weaker bands were seen in samples from four other samples. No band was noted from the two pediatric larynges. Different band patterns were seen among the three different tissue sites in the larynges with positive PCR products, but no consistent pattern was seen. Sequencing of the identified PCR products from selected samples confirmed that they were products of the age-associated, 4977-bp mitochondrial DNA deletion. Conclusions An age-associated mitochondrial DNA deletion was detected in several postmortem human larynges. Its presence seemed to increase in appearance with age. In the larynges in which the deletion occurred, there were individual regional differences in the occurrence of the deletion, but no consistent pattern was noted across all individuals who carried the deletion. [source]