Kurtosis analysis of neural diffusion organization

A computational framework is presented for relating the kurtosis tensor for water diffusion in brain to tissue models of brain microstructure. The tissue models are assumed to be comprised of non-exchanging compartments that may be associated with various microstructural spaces separated by cell membranes. Within each compartment the water diffusion is regarded as Gaussian, although the diffusion for the full system would typically be non-Gaussian. The model parameters are determined so as to minimize the Frobenius norm of the difference between the measured kurtosis tensor and the model kurtosis tensor. This framework, referred to as kurtosis analysis of neural diffusion organization (KANDO), may be used to help provide a biophysical interpretation to the information provided by the kurtosis tensor. In addition, KANDO combined with diffusional kurtosis imaging can furnish a practical approach for developing candidate biomarkers for neuropathologies that involve alterations in tissue microstructure. KANDO is illustrated for simple tissue models of white and gray matter using data obtained from healthy human subjects.postprin

Diffusional Kurtosis and Diffusion Tensor Imaging Reveal Different Time-Sensitive Stroke-Induced Microstructural Changes

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Isoflavones in treating watchful waiting benign prostate hyperplasia: a double-blinded, randomized controlled trial

OBJECTIVES: This study aims to determine the efficacy and safety of soy isoflavones in controlling the symptoms and signs of lower urinary tract symptoms due to benign prostate hyperplasia (BPH). DESIGN: This was a prospective, randomized, double-blind, placebo-controlled pilot study. SETTING: This trial was conducted at two hospitals in Hong Kong between May 2006 and September 2007. PARTICIPANTS: One hundred and seventy-six (176) participants diagnosed with BPH were recruited from outpatient clinics. Participants with lower urinary tract symptoms were recruited through newspaper and radio interviews, posters placed at government outpatient clinics, and a public seminar offered by the investigators. INTERVENTIONS: Participants were randomly assigned to either intervention (40 mg of isoflavones daily from Soylife 40) or placebo groups in a double-blind fashion. MAIN OUTCOME MEASURES: The primary outcome parameter of peak urine flow rate and the second outcome parameters of postresidual urine volume, lower urinary tract symptoms, testosterone, prostate-specific antigen, quality of life, diet, and safety profile (liver and renal function) were collected. All parameters were assessed at baseline, 6 months, and 12 months in a 12-month study period except testosterone, prostate-specific antigen, and safety profile, which were assessed at baseline and at 12 months. RESULTS: The peak urine flow rate (Qmax), postresidual urine volume, International Prostate Symptoms Scores (IPSS), and 36-Item Short Form Health Survey (SF-36) significantly improved from baseline to the 12th month within both groups. However, when compared between groups, Qmax (p=0.055) and incomplete emptying subscore in IPSS (p=0.05) were marginally/statistically different between the two groups from the 6th to the 12th months, in addition to the general health domain of SF-36 from the baseline to 12th month (p=0.02) and from the 6th month to the 12th month (p=0.055). Isoflavones were generally safe and well tolerated. CONCLUSIONS: This randomized control pilot study showed only slight superiority of isoflavones over placebo over 12 months with otherwise surprising beneficial effects in both groups. Tolerability of isoflavones was excellent; thus it has laid foundations for further studies of isoflavones in BPH with focus on dosage and possible specificity of the effect.published_or_final_versio

Functional deficits induced by cortical microinfarcts

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Tensor estimation for double-pulsed diffusional kurtosis imaging

Double-pulsed diffusional kurtosis imaging (DP-DKI) represents the double diffusion encoding (DDE) MRI signal in terms of six-dimensional (6D) diffusion and kurtosis tensors. Here a method for estimating these tensors from experimental data is described. A standard numerical algorithm for tensor estimation from conventional (i.e. single diffusion encoding) diffusional kurtosis imaging (DKI) data is generalized to DP-DKI. This algorithm is based on a weighted least squares (WLS) fit of the signal model to the data combined with constraints designed to minimize unphysical parameter estimates. The numerical algorithm then takes the form of a quadratic programming problem. The principal change required to adapt the conventional DKI fitting algorithm to DP-DKI is replacing the three-dimensional diffusion and kurtosis tensors with the 6D tensors needed for DP-DKI. In this way, the 6D diffusion and kurtosis tensors for DP-DKI can be conveniently estimated from DDE data by using constrained WLS, providing a practical means for condensing DDE measurements into well-defined mathematical constructs that may be useful for interpreting and applying DDE MRI. Data from healthy volunteers for brain are used to demonstrate the DP-DKI tensor estimation algorithm. In particular, representative parametric maps of selected tensor-derived rotational invariants are presented.postprin

Effects of controllable biaxial strain on the Raman spectra of monolayer graphene prepared by chemical vapor deposition

Author name used in this publication: Hui, Yeung YuAuthor name used in this publication: Lau, Shu PingAuthor name used in this publication: Hao, Jianhua2012-2013 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Pharmacokinetics and safety of ixazomib plus lenalidomide–dexamethasone in Asian patients with relapsed/refractory myeloma: a phase 1 study

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Chromosomal 16p microdeletion in Rubinstein-Taybi syndrome detected by oligonucleotide-based array comparative genomic hybridization: a case report

<p>Abstract</p> <p>Introduction</p> <p>Chromosomal aberrations of chromosome 16 are uncommon and submicroscopic deletions have rarely been reported. At present, a cytogenetic or molecular abnormality can only be detected in 55% of Rubinstein-Taybi syndrome patients, leaving the diagnosis in 45% of patients to rest on clinical features only. Interestingly, this microdeletion of 16 p13.3 was found in a young child with an unexplained syndromic condition due to an indistinct etiological diagnosis. To the best of our knowledge, no evidence of a microdeletion of 16 p13.3 with contiguous gene deletion, comprising cyclic adenosine monophosphate-response element-binding protein and tumor necrosis factor receptor-associated protein 1 genes, has been described in typical Rubinstein-Taybi syndrome.</p> <p>Case presentation</p> <p>We present the case of a three-year-old Malaysian Chinese girl with a <it>de novo </it>microdeletion on the short arm of chromosome 16, identified by oligonucleotide array-based comparative genomic hybridization. Our patient showed mild to moderate global developmental delay, facial dysmorphism, bilateral broad thumbs and great toes, a moderate size atrial septal defect, hypotonia and feeding difficulties. A routine chromosome analysis on 20 metaphase cells showed a normal 46, XX karyotype. Further investigation by high resolution array-based comparative genomic hybridization revealed a 120 kb microdeletion on chromosomal band 16 p13.3.</p> <p>Conclusion</p> <p>A mutation or abnormality in the cyclic adenosine monophosphate-response element-binding protein has previously been determined as a cause of Rubinstein-Taybi syndrome. However, microdeletion of 16 p13.3 comprising cyclic adenosine monophosphate-response element-binding protein and tumor necrosis factor receptor-associated protein 1 genes is a rare scenario in the pathogenesis of Rubinstein-Taybi syndrome. Additionally, due to insufficient coverage of the human genome by conventional techniques, clinically significant genomic imbalances may be undetected in unexplained syndromic conditions of young children. This case report demonstrates the ability of array-based comparative genomic hybridization to offer a genome-wide analysis at high resolution and provide information directly linked to the physical and genetic maps of the human genome. This will contribute to more accurate genetic counseling and provide further insight into the syndrome.</p

The prognostic value of the hypoxia markers CA IX and GLUT 1 and the cytokines VEGF and IL 6 in head and neck squamous cell carcinoma treated by radiotherapy ± chemotherapy

BACKGROUND: Several parameters of the tumor microenvironment, such as hypoxia, inflammation and angiogenesis, play a critical role in tumor aggressiveness and treatment response. A major question remains if these markers can be used to stratify patients to certain treatment protocols. The purpose of this study was to investigate the inter-relationship and the prognostic significance of several biological and clinicopathological parameters in patients with head and neck squamous cell carcinoma (HNSCC) treated by radiotherapy ± chemotherapy. METHODS: We used two subgroups of a retrospective series for which CT-determined tumoral perfusion correlated with local control. In the first subgroup (n = 67), immunohistochemistry for carbonic anhydrase IX (CA IX) and glucose transporter-1 (GLUT-1) was performed on the pretreatment tumor biopsy. In the second subgroup (n = 34), enzyme linked immunosorbent assay (ELISA) was used to determine pretreatment levels of the cytokines vascular endothelial growth factor (VEGF) and interleukin-6 (IL-6) in serum. Correlation was investigated between tumoral perfusion and each of these biological markers, as well as between the markers mutually. The prognostic value of these microenvironmental parameters was also evaluated. RESULTS: For CA IX and GLUT-1, the combined assessment of patients with both markers expressed above the median showed an independent correlation with local control (p = 0.02) and disease-free survival (p = 0.04) with a trend for regional control (p = 0.06). In the second subgroup, IL-6 pretreatment serum level above the median was the only independent predictor of local control (p = 0.009), disease-free survival (p = 0.02) and overall survival (p = 0.005). CONCLUSION: To our knowledge, we are the first to report a link in HNSCC between IL-6 pretreatment serum levels and radioresistance in vivo. This link is supported by the strong prognostic association of pretreatment IL-6 with local control, known to be the most important parameter to judge radiotherapy responses. Furthermore, the combined assessment of CA IX and GLUT-1 correlated independently with prognosis. This is a valuable indication that a combined approach is important in the investigation of prognostic markers

CCL2 recruits inflammatory monocytes to facilitate breast-tumour metastasis

Macrophages abundantly found in the tumor microenvironment enhance malignancy(1). At metastatic sites a distinct population of metastasis associated macrophages (MAMs) promote tumor cell extravasation, seeding and persistent growth(2). Our study has defined the origin of these macrophages by showing Gr1+ inflammatory monocytes (IMs) are preferentially recruited to pulmonary metastases but not primary mammary tumors, a process also found for human IMs in pulmonary metastases of human breast cancer cells. The recruitment of these CCR2 (receptor for chemokine CCL2) expressing IMs and subsequently MAMs and their interaction with metastasizing tumor cells is dependent on tumor and stromal synthesized CCL2 (FigS1). Inhibition of CCL2/CCR2 signaling using anti-CCL2 antibodies blocks IM recruitment and inhibits metastasis in vivo and prolongs the survival of tumor-bearing mice. Depletion of tumor cell-derived CCL2 also inhibits metastatic seeding. IMs promote tumor cell extravasation in a process that requires monocyte-derived VEGF. CCL2 expression and macrophage infiltration are correlated with poor prognosis and metastatic disease in human breast cancer (Fig S2)(3-6). Our data provides the mechanistic link between these two clinical associations and indicates new therapeutic targets for treating metastatic breast disease