Imaging Breast Microcalcifications Using Dark-Field Signal in Propagation-Based Phase-Contrast Tomography.

Breast microcalcifications are an important primary radiological indicator of breast cancer. However, microcalcification classification and diagnosis may be still challenging for radiologists due to limitations of the standard 2D mammography technique, including spatial and contrast resolution. In this study, we propose an approach to improve the detection of microcalcifications in propagation-based phase-contrast X-ray computed tomography of breast tissues. Five fresh mastectomies containing microcalcifications were scanned at different X-ray energies and radiation doses using synchrotron radiation. Both bright-field (i.e. conventional phase-retrieved images) and dark-field images were extracted from the same data sets using different image processing methods. A quantitative analysis was performed in terms of visibility and contrast-to-noise ratio of microcalcifications. The results show that while the signal-to-noise and the contrast-to-noise ratios are lower, the visibility of the microcalcifications is more than two times higher in the dark-field images compared to the bright-field images. Dark-field images have also provided more accurate information about the size and shape of the microcalcifications.

The effect of hemoperfusion on the outcome, clinical and laboratory findings of patients with severe COVID-19: a retrospective study.

Hemoperfusion is a method of blood filtering to remove toxins and inflammatory factors. Cytokine storms and high levels of inflammatory factors play a role in the pathogenesis of coronavirus disease 2019 (COVID-19). The present study aims to evaluate the effect of hemoperfusion on the clinical and laboratory findings and outcomes of patients with severe COVID-19. Forty-eight patients with severe COVID-19 and a positive PCR test, who were admitted to the intensive care unit (ICU), participated in the study. All patients were treated by routine treatment protocol for COVID-19. Hemoperfusion was performed for 24 patients in addition to treatment with conventional antiviral therapies. The other 24 patients made up the control group. Demographic data, laboratory findings and patient outcomes before and after treatment were retrospectively collected and analysed. There was no significnt difference in mortality or length of hospital stays between the control group and the hemoperfusion group. The breathing rate (P-vaalue = 0.001) and heart beat rate (P-value = 0.028) of patients decreased after hemoperfusion. The hemoperfusion resulted in a significant increase in the SpO2 levels and a significant decrease in the CRP of patients compared to the conventional treatment (P-value = 0.009). Hemoperfusion can improve respiratory distress. It can reduce the CRP in patients with severe COVID-19 but has no effect on mortality.

Dark-field signal extraction in propagation-based phase-contrast imaging.

A method for extracting the dark-field signal in propagation-based phase-contrast imaging is proposed. In the case of objects consisting predominantly of a single material, or several different materials with similar ratios of the real decrement to the imaginary part of the complex refractive index, the proposed method requires a single image for extraction of the dark-field signal in two-dimensional projection imaging. In the case of three-dimensional tomographic imaging, the method needs only one image to be collected at each projection angle. Initial examples using simulated and experimental data indicate that this method can improve visualization of small sharp features inside a larger object, e.g. the visualization of microcalcifications in propagation-based x-ray breast cancer imaging. It is suggested that the proposed approach may be useful in other forms of biomedical imaging, where it can help one to obtain additional small-angle scattering information without increasing the radiation dose to the sample.

Adapted MMSE and TYM cognitive tests: how much powerful in screening for Alzheimer's disease in Iranian people.

Alzheimer's disease (AD) is a major global health priority and providing an efficient way for early diagnosis of people developing dementia is important. The Mini-Mental State Examination (MMSE, total score = 30) and Test Your Memory (TYM, total score = 50) are widely used as screening tests for cognitive function. In the present study 174 subjects including healthy people (CON group) and those having Alzheimer's disease (AD group) were introduced to MMSE and TYM cognitive tests adjusted to Iranian population. Sensitivities and specificities with optimal cut-off scores, area under curve (AUC), positive predictive value (PPV) and negative predictive value (NPV) were measured for both tests. The MMSE scores of the CON and AD groups were 23.77 ± 0.327 and 10.88 ± 0.762, respectively. The TYM scores were 44.32 ± 0.389 and 14.37 ± 1.368 in the CON and AD participants, respectively. Findings in the MMSE test were: AUC = 0.962, optimal cut-off score = 18.5, sensitivity = 0.90 and specificity = 0.96. Values in the TYM test were: AUC = 0.991, optimal cut-off score = 31, sensitivity = 0.90 and specificity = 1. We found no correlation between the cognitive performance and age in the CON group but a positive correlation in the AD patients. On the other hand, t-test analysis indicated that achievement of the test scores are significantly sex dependent, with more scores attained by the females. Taken together, in regard to correct classification rate (CCR); the TYM test seems to be more appropriate for cognitive screening in our study. However, considering an analogous AUC, both tests are comparable and have high sensitivity and specificity for discriminating between people with and without AD.

Propagation-based x-ray phase-contrast tomography of mastectomy samples using synchrotron radiation.

PURPOSE: Propagation-based phase-contrast computed tomography (PB-CT) is a method for three-dimensional x-ray imaging that utilizes refraction, as well as absorption, of x rays in the tissues to increase the signal-to-noise ratio (SNR) in the resultant images, in comparison with equivalent conventional absorption-only x-ray tomography (CT). Importantly, the higher SNR is achieved without sacrificing spatial resolution or increasing the radiation dose delivered to the imaged tissues. The present work has been carried out in the context of the current development of a breast CT imaging facility at the Australian Synchrotron. METHODS: Seven unfixed complete mastectomy samples with and without breast cancer lesions have been imaged using absorption-only CT and PB-CT techniques under controlled experimental conditions. The radiation doses delivered to the mastectomy samples during the scans were comparable to those approved for mammographic screening. Physical characteristics of the reconstructed images, such as spatial resolution and SNR, have been measured and compared with the results of the radiological quality assessment of the complete absorption CT and PB-CT image stacks. RESULTS: Despite the presence of some image artefacts, the PB-CT images have outperformed comparable absorption CT images collected at the same radiation dose, in terms of both the measured objective image characteristics and the radiological image scores. The outcomes of these experiments are shown to be consistent with predictions of the theory of PB-CT imaging and previous reported experimental studies of this imaging modality. CONCLUSIONS: The results presented in this paper demonstrate that PB-CT holds a high potential for improving on the quality and diagnostic value of images obtained using existing medical x-ray technologies, such as mammography and digital breast tomosynthesis (DBT). If implemented at suitable synchrotron imaging facilities, PB-CT can be used to complement existing imaging modalities, leading to more accurate breast cancer diagnosis.

Free propagation phase-contrast breast CT provides higher image quality than cone-beam breast-CT at low radiation doses: a feasibility study on human mastectomies.

In this study we demonstrate the first direct comparison between synchrotron x-ray propagation-based CT (PB-CT) and cone-beam breast-CT (CB-CT) on human mastectomy specimens (N = 12) including different benign and malignant lesions. The image quality and diagnostic power of the obtained data sets were compared and judged by two independent expert radiologists. Two cases are presented in detail in this paper including a comparison with the corresponding histological evaluation. Results indicate that with PB-CT it is possible to increase the level of contrast-to-noise ratio (CNR) keeping the same level of dose used for the CB-CT or achieve the same level of CNR reached by CB-CT at a lower level of dose. In other words, PB-CT can achieve a higher diagnostic potential compared to the commercial breast-CT system while also delivering a considerably lower mean glandular dose. Therefore, we believe that PB-CT technique, if translated to a clinical setting, could have a significant impact in improving breast cancer diagnosis.

Optimization of propagation-based x-ray phase-contrast tomography for breast cancer imaging.

The aim of this study was to optimise the experimental protocol and data analysis for in-vivo breast cancer x-ray imaging. Results are presented of the experiment at the SYRMEP beamline of Elettra Synchrotron using the propagation-based phase-contrast mammographic tomography method, which incorporates not only absorption, but also x-ray phase information. In this study the images of breast tissue samples, of a size corresponding to a full human breast, with radiologically acceptable x-ray doses were obtained, and the degree of improvement of the image quality (from the diagnostic point of view) achievable using propagation-based phase-contrast image acquisition protocols with proper incorporation of x-ray phase retrieval into the reconstruction pipeline was investigated. Parameters such as the x-ray energy, sample-to-detector distance and data processing methods were tested, evaluated and optimized with respect to the estimated diagnostic value using a mastectomy sample with a malignant lesion. The results of quantitative evaluation of images were obtained by means of radiological assessment carried out by 13 experienced specialists. A comparative analysis was performed between the x-ray and the histological images of the specimen. The results of the analysis indicate that, within the investigated range of parameters, both the objective image quality characteristics and the subjective radiological scores of propagation-based phase-contrast images of breast tissues monotonically increase with the strength of phase contrast which in turn is directly proportional to the product of the radiation wavelength and the sample-to-detector distance. The outcomes of this study serve to define the practical imaging conditions and the CT reconstruction procedures appropriate for low-dose phase-contrast mammographic imaging of live patients at specially designed synchrotron beamlines.

Out of America: tracing the genetic footprints of the global diffusion of maize.

Maize was first domesticated in a restricted valley in south-central Mexico. It was diffused throughout the Americas over thousands of years, and following the discovery of the New World by Columbus, was introduced into Europe. Trade and colonization introduced it further into all parts of the world to which it could adapt. Repeated introductions, local selection and adaptation, a highly diverse gene pool and outcrossing nature, and global trade in maize led to difficulty understanding exactly where the diversity of many of the local maize landraces originated. This is particularly true in Africa and Asia, where historical accounts are scarce or contradictory. Knowledge of post-domestication movements of maize around the world would assist in germplasm conservation and plant breeding efforts. To this end, we used SSR markers to genotype multiple individuals from hundreds of representative landraces from around the world. Applying a multidisciplinary approach combining genetic, linguistic, and historical data, we reconstructed possible patterns of maize diffusion throughout the world from American "contribution" centers, which we propose reflect the origins of maize worldwide. These results shed new light on introductions of maize into Africa and Asia. By providing a first globally comprehensive genetic characterization of landraces using markers appropriate to this evolutionary time frame, we explore the post-domestication evolutionary history of maize and highlight original diversity sources that may be tapped for plant improvement in different regions of the world.

Three new teosintes (Zea spp., Poaceae) from México.

PREMISE OF THE STUDY: Teosinte species are the closest relatives of maize and represent an important but increasingly rare genetic resource for maize improvement and the study of evolution by domestication. Three morphologically and ecologically distinct teosinte populations were recently discovered in México. The taxonomic status of these rare and endangered populations was investigated by detailed comparisons to previously characterized wild Zea species. • METHODS: Three new teosinte populations were compared to known teosinte taxa on the basis of morphological, ecogeographic, cytological, and molecular characteristics. Phenetic and phylogenetic analyses were performed using morphological and molecular data, respectively. • KEY RESULTS: The newly discovered populations are distinct from each other and from other Zea species to represent three new entities based on their unique combinations of morphological, ecological, ploidy, and DNA markers. A perennial diploid population from Nayarit is distinguished by early maturing plants, and having male inflorescences with few tassel branches and long spikelets. A perennial tetraploid population from Michoacán is characterized by tall and late maturing plants, and having male inflorescences with many branches. An annual diploid population from Oaxaca is characterized by having male inflorescences with fewer branches and longer spikelets than those found in the sister taxa Z. luxurians and Z. nicaraguensis, plants with high thermal requirements, and very long seed dormancy. • CONCLUSIONS: Evidence from multiple independent sources suggests placement of the three new populations of teosinte as distinct entities within section Luxuriantes of the genus Zea. However, more extensive DNA marker or sequence data are required to resolve the taxonomy of this genus.

Grouping of accessions of Mexican races of maize revisited with SSR markers.

Mexican races of maize (Zea mays L.) represent a valuable genetic resource for breeding and genetic surveys. We applied simple sequence repeat (SSR) markers to characterize 25 accessions of races of maize from Mexico. Our objectives were to (1) study the molecular genetic diversity within and among these accessions and (2) examine their relationships as assumed previously on the basis of morphological data. A total of 497 individuals were fingerprinted with 25 SSR markers. We observed a high total number of alleles (7.84 alleles per locus) and total gene diversity (0.61), confirming the broad genetic base of the maize races from Mexico. In addition, the accessions were grouped into distinct racial complexes on the basis of a model-based clustering approach. The principal coordinate analyses of the four Modern Incipient hybrids corroborated the proposed parental races of Chalqueño, Cónico Norteño, Celaya, and Bolita on the basis of the morphological data. Consequently, for some of the accessions, hybridizations provide a clue that can further be used to explain the associations among the Mexican races of maize.

Comparison of the S RNA segments among Japanese isolates and Taiwanese isolates of Watermelon silver mottle virus.

The complete nucleotide sequences of the S RNA of two Japanese isolates of Watermelon silver mottle virus were determined. One was isolated from naturally infected watermelon and causes malformation on upper leaves of Tetragonia expansa. The other was isolated from melon and causes characteristic yellow necrotic lesions on upper leaves of T. expansa. The total nucleotide sequences of the S RNA of WS-O and WS-Y were 3553 nt and 3558 nt long, respectively. Both the nucleotide sequences and the deduced amino acid sequences of WS-O and WS-Y were quite similar even though the symptoms on T. expansa are quite different. They were also significantly similar to those of the Taiwanese isolates, Topso-W and Tospo-To. These results suggested that the Japanese isolates and the Taiwanese isolates of WSMoV were classified as one group not only serologically but also genetically. Within the S RNA sequences, the most variable region was the intergenic region between the N gene and the NSs gene. This was due to a 20 nt insertion between the Japanese isolates and the Taiwanese isolates.

Learning to implement the medical home in communities.

Practicing the Medical Home within communities is prefaced by university training through pediatric residency programs. Through collaboration experiences, future and practicing pediatricians can learn skills to form effective interprofessional relationships, thereby supporting families and children. Seeing parents as enabled partners and creating interdependent relationships with community members and professionals, enhances the medical home's broad base of support for families.

Plant genetic resources: what can they contribute toward increased crop productivity?

To feed a world population growing by up to 160 people per minute, with >90% of them in developing countries, will require an astonishing increase in food production. Forecasts call for wheat to become the most important cereal in the world, with maize close behind; together, these crops will account for approximately 80% of developing countries' cereal import requirements. Access to a range of genetic diversity is critical to the success of breeding programs. The global effort to assemble, document, and utilize these resources is enormous, and the genetic diversity in the collections is critical to the world's fight against hunger. The introgression of genes that reduced plant height and increased disease and viral resistance in wheat provided the foundation for the "Green Revolution" and demonstrated the tremendous impact that genetic resources can have on production. Wheat hybrids and synthetics may provide the yield increases needed in the future. A wild relative of maize, Tripsacum, represents an untapped genetic resource for abiotic and biotic stress resistance and for apomixis, a trait that could provide developing world farmers access to hybrid technology. Ownership of genetic resources and genes must be resolved to ensure global access to these critical resources. The application of molecular and genetic engineering technologies enhances the use of genetic resources. The effective and complementary use of all of our technological tools and resources will be required for meeting the challenge posed by the world's expanding demand for food.

The role of the medical home and interprofessional collaboration.

The medical home plays a critical role on the interprofessional team to improve school readiness of children before they enter primary school. School readiness and optimal health require a combination of medical care with health and social services both to prevent and to improve the effects of negative conditions. Hawaii Medical Association has two new projects aimed toward that end.

Practical considerations for maintaining germplasm in maize.

The main goals of genetic resource management are to acquire, maintain, distribute, characterize, regenerate, preserve, evaluate, and utilize the genetic diversity of crops and their wild relatives. The objectives of this study for ex-situ conservation of maize (Zea mays L.) are to review and describe: (1) practical regeneration methods that are based on population genetic theory; (2) practical problems encountered in choosing core subsets of a maize collection. Whenever possible, regeneration procedures should control the number of pollen parents (male gametes; through controlled hand pollination) and the number of female parent gametes (by harvesting equal numbers of kernels from each seed plant). When the number of pollen and seed parents are controlled during regeneration, the effective population size (Ne) is twice the size of the original population (N). Examples of practical methods for controlling the number of male and female parents are presented. The procedure involves random-paired plant crosses and taking equal numbers of seeds from each maize ear. To form a core subset, accessions of a maize race are subdivided through a stratified sampling procedure. Delineation of a core subset from a Tuxpeño racial collection is described as an example.

Statistical genetic considerations for maintaining germ plasm collections.

One objective of the regeneration of genetic populations is to maintain at least one copy of each allele present in the original population. Genetic diversity within populations depends on the number and frequency of alleles across all loci. The objectives of this study on outbreeding crops are: (1) to use probability models to determine optimal sample sizes for the regeneration for a number of alleles at independent loci; and (2) to examine theoretical considerations in choosing core subsets of a collection. If we assume that k-1 alleles occur at an identical low frequency of p0 and that the k(th) allele occurs at a frequency of 1-[(k-1)p0], for loci with two, three, or four alleles, each with a p0 of 0.05, 89-110 additional individuals are required if at least one allele at each of 10 loci is to be retained with a 90% probability; if 100 loci are involved, 134-155 individuals are required. For two, three, or four alleles, when p0 is 0.03 at each of 10 loci, the sample size required to include at least one of the alleles from each class in each locus is 150-186 individuals; if 100 loci are involved, 75 additional individuals are required. Sample sizes of 160-210 plants are required to capture alleles at frequencies of 0.05 or higher in each of 150 loci, with a 90-95% probability. For rare alleles widespread throughout the collection, most alleles with frequencies of 0.03 and 0.05 per locus will be included in a core subset of 25-100 accessions.

[T-serotype distribution of group A hemolytic streptococci in a rapidly expanding residential area in Sanda City, Hyogo Prefecture, with reference to an outbreak of serotype T-28 in autumn, 1988].

In the fall of 1988, an outbreak of streptococcal infections was observed at 2 pediatric clinics in Sanda City, Hyogo prefecture. The 2 clinics were independent of each other; one (clinic A) was located in the down town area, in the older part of the city, where there is little population turn over, while the other (clinic B) was in a newly developed-fast growing residential district. The strains and the distribution of T-serotypes isolated at each location are as follows: clinic A; 58 strains (34.5% serotype T-4, 31.0% serotype T-12, 10.3% serotype T-1, and 23.3% serotype T-28), clinic B; 43 strains (48.8% serotype T-28, 23.3% serotype T-12, 11.6% serotype T-4 and 7.0% serotype T-1). According to the data from Kobe City infectious disease surveillance center, there were a total of 102 group A hemolytic streptococci strains isolated in 1988, the T-serotypes distribution of which was as follows: 47.0% serotype T-4, 15.7% serotype the T-12, 10.8% serotype T-1 and 9.8% serotype T-28. Serotype T-4 was dominant here, as it was in location A of Sanda City. The epidemic proportion of serotype T-28 found at location B is considered to be due to the fact that location B has very little social interaction with location A and other areas. No difference was observed among the different serotypes on the drug susceptibility test: all strains showed a sensitivity to ampicillin and penicillin G, but were resistant to tetracycline and chloramphenicol.