Genetic variations of 21 STR markers on chromosomes 13, 18, 21, X, and Y in the south Iranian population.

Quantitative fluorescent polymerase chain reaction (QF-PCR), in recent years, has been accepted as a rapid, high throughput, and sensitive method for prenatal diagnosis of common chromosomal aneuploidies. Since short tandem repeats (STRs) are the cornerstone of QF-PCR technique, selection of the most polymorphic STR markers is an essential step for a successful QF-PCR assay. The genetic variation parameters of each STR marker differ among different populations. In this study, we investigated the size, frequency, heterozygosity, polymorphism information content, power of discrimination, and other genetic polymorphism data for 21 STR markers on chromosomes 13, 18, 21, X, and Y in 1000 amniotic fluid samples obtained from south Iranian women. Our results showed that all the 21 STR markers are highly polymorphic and informative in our population. The heterozygosity, polymorphism information content, and power of discrimination of the markers were 62-91.1%, 0.61-0.91, and 0.830-0.976, respectively. The locus D18S386 was the most polymorphic STR, while the locus DXYS218 was the least polymorphic STR among all the studied STRs. The present study has provided extensive data regarding the efficiency of the 21 STR markers for diagnosis of chromosomes 13, 18, 21, X, and Y aneuploidies in the south Iranian population.

Differential expression analysis of balding and nonbalding dermal papilla microRNAs in male pattern baldness with a microRNA amplification profiling method.

BACKGROUND: Male pattern baldness or androgenetic alopecia is a common disorder affecting almost 50% of men throughout their lifetime, with androgens and genetics having significant contributing aetiologies. In contrast to the positive regulatory effect of androgens on body hair growth, they are thought to alter scalp hair follicle behaviour pathophysiologically, leading to male pattern baldness. However, the exact mechanisms of this paradoxical action have not yet been elucidated. The role of microRNAs, a novel group of noncoding RNAs impacting almost every aspect of biology, health and human diseases, has been documented in hair follicle formation. In addition, their deregulation in cancer of the prostate, a target organ of androgens, has also been well established. OBJECTIVES: To investigate the possible contribution of microRNAs in the pathophysiology of male pattern baldness. METHODS: We initially screened microRNA expression profiles of balding and nonbalding hair follicle papillae with a sensitive microRNA cloning method, microRNA amplification profiling, and statistically analysed significant differentially expressed microRNAs in balding relative to nonbalding dermal papillae, with real-time polymerase chain reaction as a confirmatory method to quantify expression in eight individuals affected with the disorder. RESULTS: We detected the significant upregulation of miR-221, miR-125b, miR-106a and miR-410 in balding papilla cells. CONCLUSIONS: We found four microRNAs that could participate in the pathogenesis of male pattern baldness. Regarding the strong therapeutic potential of microRNAs and the easy accessibility of hair follicles for gene therapy, microRNAs are possible candidates for a new generation of revolutionary treatments.

A k-space method for large-scale models of wave propagation in tissue.

Large-scale simulation of ultrasonic pulse propagation in inhomogeneous tissue is important for the study of ultrasound-tissue interaction as well as for development of new imaging methods. Typical scales of interest span hundreds of wavelengths; most current two-dimensional methods, such as finite-difference and finite-element methods, are unable to compute propagation on this scale with the efficiency needed for imaging studies. Furthermore, for most available methods of simulating ultrasonic propagation, large-scale, three-dimensional computations of ultrasonic scattering are infeasible. Some of these difficulties have been overcome by previous pseudospectral and k-space methods, which allow substantial portions of the necessary computations to be executed using fast Fourier transforms. This paper presents a simplified derivation of the k-space method for a medium of variable sound speed and density; the derivation clearly shows the relationship of this k-space method to both past k-space methods and pseudospectral methods. In the present method, the spatial differential equations are solved by a simple Fourier transform method, and temporal iteration is performed using a k-t space propagator. The temporal iteration procedure is shown to be exact for homogeneous media, unconditionally stable for "slow" (c(x) < or = c0) media, and highly accurate for general weakly scattering media. The applicability of the k-space method to large-scale soft tissue modeling is shown by simulating two-dimensional propagation of an incident plane wave through several tissue-mimicking cylinders as well as a model chest wall cross section. A three-dimensional implementation of the k-space method is also employed for the example problem of propagation through a tissue-mimicking sphere. Numerical results indicate that the k-space method is accurate for large-scale soft tissue computations with much greater efficiency than that of an analogous leapfrog pseudospectral method or a 2-4 finite difference time-domain method. However, numerical results also indicate that the k-space method is less accurate than the finite-difference method for a high contrast scatterer with bone-like properties, although qualitative results can still be obtained by the k-space method with high efficiency. Possible extensions to the method, including representation of absorption effects, absorbing boundary conditions, elastic-wave propagation, and acoustic nonlinearity, are discussed.

Backprojection by upsampled Fourier series expansion and interpolated FFT.

A fast backprojection method through the use of interpolated fast Fourier transform (FFT) is presented. The computerized tomography (CT) reconstruction by the convolution backprojection (CBP) method has produced precise images. However, the backprojection part of the conventional CBP method is not very efficient. The authors propose an alternative approach to interpolating and backprojecting the convolved projections onto the image frame. First, the upsampled Fourier series expansion of the convolved projection is calculated. Then, using a Gaussian function, it is projected by the aliasing-free interpolation of FFT bins onto a rectangular grid in the frequency domain. The total amount of computation in this procedure for a 512x512 image is 1/5 of the conventional backprojection method with linear interpolation. This technique also allows the arbitrary control of the frequency characteristics.