Controlling selectivity in N-heterocycle directed borylation of indoles.

Electrophilic borylation of indoles with BX3 (X = Cl or Br) using directing groups installed at N1 can proceed at the C2 or the C7 position. The six membered heterocycle directing groups utilised herein, pyridines and pyrimidine, result in indole C2 borylation being the dominant outcome (in the absence of a C2-substituent). In contrast, C7 borylation was achieved using five membered heterocycle directing groups, such as thiazole and benzoxazole. Calculations on the borylation of indole substituted with a five (thiazole) and a six (pyrimidine) membered heterocycle directing group indicated that borylation proceeds via borenium cations with arenium cation formation having the highest barrier in both cases. The C7 borylated isomer was calculated to be the thermodynamically favoured product with both five and six membered heterocycle directing groups, but for pyrimidine directed indole borylation the C2 product was calculated to be the kinetic product. This is in contrast to thiazole directed indole borylation with BCl3 where the C7 borylated isomer is the kinetic product too. Thus, heterocycle ring size is a useful way to control C2 vs. C7 selectivity in N-heterocycle directed indole C-H borylation.

Intramolecular (directed) electrophilic C-H borylation.

The intramolecular C-H borylation of (hetero)arenes and alkenes using electrophilic boranes is a powerful transition metal free methodology for forming C-B bonds. These C-H borylation reactions are preceded by intermolecular bond (both dative and covalent) formation, with examples proceeding via initial C-B and N-B bond formation dominating this field thus both are discussed in depth herein. Less prevalent intramolecular electrophilic C-H borylation reactions that proceed by intermolecular O-B, S-B and P-B bond formation are also summarised. Mechanistic studies are presented that reveal two mechanisms for C-H borylation, (i) electrophilic aromatic substitution (prevalent with B-X electrophiles); (ii) σ-bond metathesis mediated (prevalent with B-H and B-R electrophiles). To date, intramolecular electrophilic C-H borylation is utilised mainly for accessing boron containing conjugated organic materials, however recent developments, summarized herein alongside early studies, have highlighted the applicability of this methodology for forming synthetically versatile organo-boronate esters and boron containing bioactives. The multitude of synthetic procedures reported for intramolecular electrophilic C-H borylation contain many common features and this enables key requirements for successful C-H borylation and the factors effecting regioselectivity and substrate scope to be identified, discussed and summarized.

Dynamical plane wave solutions for the Heisenberg model of ferromagnetic spin chains with beta derivative evolution and obliqueness.

The oblique plane waves with their dynamical behaviors for a (2+1)-dimensional nonlinear Schrödinger equation (NLSE) having beta derivative spatial-temporal evolution are investigated. In order to study such phenomena, NLSE is converted to a nonlinear ordinary differential equation with a planar dynamical system by considering the variable wave transform with obliqueness and the properties of the beta derivative. Some more new general forms of analytical solutions, like bright, dark, singular, and pure periodic solutions of NLSE are constructed by employing the auxiliary ordinary differential equation method and the extended simplest equation method. The effect of obliqueness and beta derivative parameter on several types of wave structures along with the phase portrait diagrams are reported by considering some special values of parameters for the existence of attained solutions. It is found that the planar dynamical system is not supported by any type of orbit for Θ = 45 0 . It is also confirmed from the obtained solutions that no plane waves are generated for Θ = 45 0 . The presented studies on bifurcation analysis and analytical solutions for (2+1)-dimensional NLSE would be very useful to understand the physical scenarios of nonlinear spin dynamics in magnetic materials for Heisenberg models of ferromagnetic spin chains.

Characterization of stem cells in Dupuytren's disease.

BACKGROUND: Dupuytren's disease (DD) is a common fibroproliferative disease of unknown origin. The source of abnormal cells leading to DD formation remains underexplored. In addition to fascia, palmar skin and fat-derived cells may be a potential source of cells causing DD. This study aimed to profile haematopoietic and mesenchymal stem cells in different DD tissue components compared with tissue removed at carpal tunnel surgery (control). METHODS: Biopsies were taken from the diseased cord, nodule, perinodular fat and skin overlying the nodule of ten patients with DD and compared with control tissue from seven patients having surgery for carpal tunnel syndrome. Fluorescence-activated cell sorting (FACS), immunohistochemistry and quantitative real-time polymerase chain reaction (QRT-PCR) were used to identify expression of selected stem cell markers. RESULTS: FACS and QRT-PCR analysis identified the highest RNA expression and number of cells positive for adipocyte stem cell markers (CD13 and CD29) in the DD nodule in comparison with carpal tunnel control tissue (P = 0·053). CD34 RNA was overexpressed, and a higher percentage of these cells was present in DD skin compared with carpal tunnel skin (P = 0·001). CONCLUSION: Each structural component of DD (cord, nodule, perinodular fat and skin) had distinct stem cell populations. These findings support the hypothesis that DD may result from mesenchymal progenitor cell expansion.

Fibroblasts from the growing margin of keloid scars produce higher levels of collagen I and III compared with intralesional and extralesional sites: clinical implications for lesional site-directed therapy.

BACKGROUND: Overproduction of collagen and its abnormal assembly are hallmarks of keloid scars. Type I/III collagen ratios are altered in keloids compared with normal skin. Fibroblasts from different sites in keloid tissue, perilesional compared with intralesional and extralesional sites, show differential apoptosis and contraction. Additionally, early vs. later cell culture passages display differential collagen expression. We therefore hypothesize that keloid fibroblasts from the growing margin of the keloid express higher levels of collagen type I and III, and that collagen production is altered by extended cell culture passage. OBJECTIVES: (i) To measure collagen I and III at mRNA and protein levels quantitatively in keloid fibroblasts, growth media and tissue sections; and (ii) to perform tissue staining for collagen I and III expression in different lesional sites. METHODS: Keloid fibroblast cultures from intralesional, perilesional and extralesional sites (n = 8 separate keloid cases, yielding 64 biopsy samples) were established from passage 0 to passage 3. Collagen I and III mRNA was quantified using quantitative reverse transcription-polymerase chain reaction. We also measured the protein levels quantitatively by developing a highly specific and sensitive capture sandwich enzyme-linked immunosorbent assay. A novel in-cell Western blotting was carried out in addition to haematoxylin and eosin and Herovici staining on keloid tissue sections for collagen I and III. RESULTS: Collagen types I and III were significantly higher (P < 0·03) in fibroblasts from the growing margin (perilesional site) compared with extralesional and intralesional keloid biopsy sites. As the passage number increased, the amount of collagen I significantly (P < 0·05) decreased and the collagen I/III ratio also decreased. CONCLUSIONS: Our data show that cells from the growing margin of keloid scars have a higher production of collagen I and III compared with other lesional sites. Additionally, temporal extension of cell passage affects collagen production. Clinically these findings may influence selection and interpretation of extended cell passage and provide future direction for lesional site-specific therapy in keloid scars.

Differential distribution of haematopoietic and nonhaematopoietic progenitor cells in intralesional and extralesional keloid: do keloid scars provide a niche for nonhaematopoietic mesenchymal stem cells?

BACKGROUND: Keloid disease is a benign, quasineoplastic disease with a high recurrence rate. Mesenchymal-like stem cells (MLSC) have previously been demonstrated in keloid scars and may be involved in keloid pathobiology. However, as these cells have only been examined by single colour fluorescence activated cell sorting (FACS) alone, they need to be more comprehensively characterized so that the key cellular contributors to keloid scars can be better understood. OBJECTIVES: To identify and characterize MLSC in intralesional and extralesional keloid, and to distinguish haematopoietic stem cells (HSC) from mesenchymal stem cells (MSC). METHODS AND PATIENTS: Punch biopsies from intralesional (top, middle and margin) and extralesional keloid scar sites were obtained from 17 patients with a keloid. Multicolour FACS analysis using antibodies specific for HSC markers CD34 and CD117 and MSC markers CD13, CD29, CD44 and CD90 was performed on freshly isolated keloid scar cells and on passage 0 and 1 cells. This was complemented by real-time quantitative polymerase chain reaction (PCR) and immunohistological in situ analyses. RESULTS: Keloid scars contain distinct subpopulations of MLSCs. Cells positive for CD13, CD29, CD44 and CD90 were found to be significantly (P<0·05) higher in the top and middle compartments of keloid scars compared with extralesional skin, where cells positive for CD34, CD90 and CD117 (representing HSCs) predominated. A unique population of CD34+ cells (cells positive for CD13, CD29, CD34, CD44 and CD90) were found in keloid scars and in extralesional skin. FACS and quantitative PCR analysis showed that many of the MSC markers were progressively downregulated and all HSC markers were lost during extended keloid fibroblast culture up to passage 1. CONCLUSION: We have found distinct subpopulations of haematopoietic and nonhaematopoietic MSC in keloid scars, whereby HSC accumulate extralesionally, while keloids seem to provide a niche environment for nonhaematopoietic MSC. Future therapy of keloids may have to target differentially both stem cell populations in order to deprive these tumours of their regenerative cell pools.

Diagnostic code agreement for electronic health records and claims data for tuberculosis.

OBJECTIVE: To measure the frequency of diseases related to latent tuberculosis infection (LTBI) and tuberculosis (TB), we assessed the agreement between diagnosis codes for TB or LTBI in electronic health records (EHRs) and insurance claims for the same person.METHODS: In a US population-based, retrospective cohort study, we matched TB-related Systematized Nomenclature of Medicine-Clinical Terms (SNOMED CT) EHR codes and International Statistical Classification of Diseases, 10th Revision, Clinical Modification (ICD-10-CM) claims codes. Furthermore, LTBI was identified using a published ICD-based algorithm and all LTBI- and TB-related SNOMED CT codes.RESULTS: Of people with the 10 most frequent TB-related claim codes, 50% did not have an exact-matched EHR code. Positive tuberculin skin test was the most frequent unmatched EHR code and people with the 10 most frequent TB EHR codes, 40% did not have an exact-matched claim code. The most frequent unmatched claim code was TB screening encounter. EHR codes for LTBI matched to claims codes for TB testing; pulmonary TB; and nonspecific, positive or adverse tuberculin reaction.CONCLUSION: TB-related EHR codes and claims diagnostic codes often disagree, and people with claims codes for LTBI have unexpected EHR codes, indicating the need to reconcile these coding systems.

Identification of fibrocytes from mesenchymal stem cells in keloid tissue: a potential source of abnormal fibroblasts in keloid scarring.

Abnormal fibroblasts have been implicated in keloid formation, a benign but fibroproliferative skin disorder. However, the exact source of these cells remains unknown. Fibrocytes are considered to be hybrid mesenchymal/hematopoietic cells, having been identified in various fibrotic disorders as the precursors of fibroblasts. Therefore, we hypothesized that a population of fibrocytes is present in keloid tissue as opposed to the mesenchymal stem cells (MSCs). We compared the proportion of MSCs in keloid versus bone marrow-derived cells and compared fibrocytes in keloid as opposed to normal scar tissue. We also investigated the propagation of fibrocytes in serum-supplemented versus serum-free media. Using multicolor fluorescence-activated cell analysis, we found distinct populations of MSCs (CD34(-)CD73(+)CD90(+)CD105(+)) that were different from CD45RO(+)25F9(+)MRP8/14(+) fibrocytes present in keloid tissue, while very few fibrocytes were observed in normal scar tissue. The proportion of keloid-derived cells in serum-free or serum-supplemented cultures expressing these fibrocyte markers was greater than from cultures derived from normal scar tissue (p < 0.05). We found that the proliferation of CD45(+)/Col1(+) keloid cells in vitro was greater in serum-free media compared to serum-supplemented media. This is the first study to have identified fibrocytes isolated from keloid tissue and normal scars, utilizing a specific set of markers for fibrocytes. This finding may aid our understanding of the origin of abnormal fibroblasts identified in keloid scarring. The identification of fibrocyte populations distinct from MSCs in keloid scar tissue could lead to novel targets for therapeutic intervention, treatment and prevention of recurrence.

Exploring the application of mesenchymal stem cells in bone repair and regeneration.

Failure of bone repair is a challenging problem in the management of fractures. There is a limited supply of autologous bone grafts for treating nonunions, with associated morbidity after harvesting. There is need for a better source of cells for repair. Mesenchymal stem cells (MSCs) hold promise for healing of bone because of their capacity to differentiate into osteoblasts and their availability from a wide variety of sources. Our review aims to evaluate the available clinical evidence and recent progress in strategies which attempt to use autologous and heterologous MSCs in clinical practice, including genetically-modified MSCs and those grown on scaffolds. We have compared various procedures for isolating and expanding a sufficient number of MSCs for use in a clinical setting. There are now a number of clinical studies which have shown that implantation of MSCs is an effective, safe and durable method for aiding the repair and regeneration of bone.