The determination and application of (87) Sr/(86) Sr ratio in verifying geographical origin of wheat

As ⁸⁷ Sr/⁸⁶ Sr ratio plays a significant role in authenticating the geographical origin of foodstuff, it is important to identify where the ⁸⁷ Sr/⁸⁶ Sr signature in food comes from, and the methods of ⁸⁷ Sr/⁸⁶ Sr ratio analysis in food and environmental samples. Wheat with three genotypes, soil and groundwater samples were collected from three regions of China during harvest time of 2014. The ⁸⁷ Sr/⁸⁶ Sr ratios in the samples were determined by thermal ionization mass spectrometer in order to investigate the possible source of ⁸⁷ Sr/⁸⁶ Sr in wheat, and the concentrations of Rb and Sr in wheat and soils were also detected by inductively coupled plasma mass spectrometry and combined with ⁸⁷ Sr/⁸⁶ Sr ratio in order to trace the geographical origin of wheat. The ⁸⁷ Sr/⁸⁶ Sr ratio, the contents Rb and Sr, and Rb/Sr ratio of wheat and soil samples showed significant differences among three regions. The ⁸⁷ Sr/⁸⁶ Sr ratios and the concentrations of Rb and Sr in soils were higher than those in corresponding wheat. The ⁸⁷ Sr/⁸⁶ Sr ratio in wheat was identical to that corresponding soil NH₄ NO₃ extracts (labile fraction of soil) and groundwater. Wheat uptake more Rb than Sr. 3D distribution of ⁸⁷ Sr/⁸⁶ Sr, Rb and Sr could identify wheat samples from different regions clearly. The ⁸⁷ Sr/⁸⁶ Sr ratio of wheat reflects the ⁸⁷ Sr/⁸⁶ Sr ratio of the associated environment including soil and groundwater. It is expected that the use the parameters of ⁸⁷ Sr/⁸⁶ Sr ratio, the contents of Rb and Sr will allow to trace geographical origin of wheat. Copyright © 2017 John Wiley & Sons, Ltd.

Corneal permeation properties of a charged lipid nanoparticle carrier containing dexamethasone

Drug delivery carriers can maintain effective therapeutic concentrations in the eye. To this end, we developed lipid nanoparticles (L/NPs) in which the surface was modified with positively charged chitosan, which engaged in hydrogen bonding with the phospholipid membrane. We evaluated in vitro corneal permeability and release characteristics, ocular irritation, and drug dynamics of modified and unmodified L/NPs in aqueous humor. The size of L/NPs was uniform and showed a narrow distribution. Corneal permeation was altered by the presence of chitosan and was dependent on particle size; the apparent permeability coefficient of dexamethasone increased by 2.7 and 1.8 times for chitosan-modified and unmodified L/NPs, respectively. In conclusion, a chitosan-modified system could be a promising method for increasing the ocular bioavailability of unmodified L/NPs by enhancing their retention time and permeation into the cornea. These findings provide a theoretical basis for the development of effective drug delivery systems in the treatment of ocular disease.

Nitric oxide participates in IFN-gamma-induced HUVECs hyperpermeability

The endothelial barrier function is tightly controlled by a broad range of signaling cascades including nitric oxide-cyclic guanosine monophosphate (NO-cGMP) pathway. It has been proposed that disturbances in NO and cGMP production could interfere with proper endothelial barrier function. In this study, we assessed the effect of interferon-gamma (IFN-gamma), a pro-inflammatory cytokine, on NO and cGMP levels and examined the mechanisms by which NO and cGMP regulate the IFN-gamma-mediated HUVECs hyperpermeability. The flux of fluorescein isothiocyanate-labeled dextran across cell monolayers was used to study the permeability of endothelial cells. Here, we found that IFN-gamma significantly attenuated basal NO concentration and the increased NO levels supplied by a NO donor, sodium nitroprusside (SNP). Besides, application of IFN-gamma also significantly attenuated both the basal cGMP concentration and the increased cGMP production donated by a cell permeable cGMP analogue, 8-bromo-cyclic GMP (8-Br-cGMP). In addition, exposure of the cell monolayer to IFN-gamma significantly increased HUVECs basal permeability. However, L-NAME pretreatment did not suppress IFN-gamma-induced HUVECs hyperpermeability. L-NAME pretreatment followed by SNP or SNP pretreatment partially reduced IFN-gamma-induced HUVECs hyperpermeability. Pretreatment with a guanylate cyclase inhibitor, 6-anilino-5,8-quinolinedione (LY83583), led to a further increase in IFN-gamma-induced HUVECs hyperpermeability. The findings suggest that the mechanism underlying IFN-gamma-induced increased HUVECs permeability is partly related to the inhibition of NO production.

A comparison of computer- and hand-generated clinical dental notes with statutory regulations in record keeping

INTRODUCTION

Dental patient records should be of high quality, contain information to allow for good continuity of care and clinical defence (should the need ever arise) and, ideally, facilitate clinical audit. Handwritten dental records have been assessed for their compliance to statutory regulations, but the same cannot be levelled at computer-generated notes. This study aimed to compare and analyse the compliance of both methods of data recording with statutory regulations.

METHOD

Fifty consecutive sets of handwritten notes and 50 sets of computer-generated notes were audited for compliance with a number of legal requirements and desirable characteristics for dental records and the results compared. The standard set for compliance with all characteristics was 100%.

RESULTS

The computer-generated notes satisfied the set standard for 8 of the 11 legal requirements and three of six desirable characteristics. The handwritten notes satisfied the set standard for 1 of 11 legal requirements and none of the desirable characteristics. A statistical difference (using a 95% confidence interval) between the two methods was observed in 5 of 11 legal characteristics and three of six desirable characteristics, all of which were in favour of computer-generated notes.

CONCLUSIONS

Within the limitations of this study, computer-generated notes achieved a much higher compliance rate with the set parameters, making defence in cases of litigation, continuity of care and clinical audit easier and more efficient.

Hsa-mir-145 is the top EWS-FLI1-repressed microRNA involved in a positive feedback loop in Ewing's sarcoma

EWS-FLI1 is a chromosome translocation-derived chimeric transcription factor that has a central and rate-limiting role in the pathogenesis of Ewing's sarcoma. Although the EWS-FLI1 transcriptomic signature has been extensively characterized on the mRNA level, information on its impact on non-coding RNA expression is lacking. We have performed a genome-wide analysis of microRNAs affected by RNAi-mediated silencing of EWS-FLI1 in Ewing's sarcoma cell lines, and differentially expressed between primary Ewing's sarcoma and mesenchymal progenitor cells. Here, we report on the identification of hsa-mir-145 as the top EWS-FLI1-repressed microRNA. Upon knockdown of EWS-FLI1, hsa-mir-145 expression dramatically increases in all Ewing's sarcoma cell lines tested. Vice versa, ectopic expression of the microRNA in Ewing's sarcoma cell lines strongly reduced EWS-FLI1 protein, whereas transfection of an anti-mir to hsa-mir-145 increased the EWS-FLI1 levels. Reporter gene assays revealed that this modulation of EWS-FLI1 protein was mediated by the microRNA targeting the FLI1 3'-untranslated region. Mutual regulations of EWS-FLI1 and hsa-mir-145 were mirrored by an inverse correlation between their expression levels in four of the Ewing's sarcoma cell lines tested. Consistent with the role of EWS-FLI1 in Ewing's sarcoma growth regulation, forced hsa-mir-145 expression halted Ewing's sarcoma cell line growth. These results identify feedback regulation between EWS-FLI1 and hsa-mir-145 as an important component of the EWS-FLI1-mediated Ewing's sarcomagenesis that may open a new avenue to future microRNA-mediated therapy of this devastating malignant disease.

A small nuclear RNA, hdm365, is the major processing product of the human mdm2 gene

mdm2 encodes for an E3 ubiquitin ligase targeting constitutively expressed p53 for proteasomal degradation. Several protein isoforms have been described for human MDM2 (HDM2), some of which may correspond to splicing variants detectable by RT-PCR in many tumors. Upon cellular stress, p53 becomes resistant to MDM2 and, in a feedback loop, up-regulates mdm2 transcription. The physiological relevance of stress-induced mdm2 gene activity is not well understood. We describe a small nuclear RNA of 365 bases comprised of the first five hdm2 exons and lacking polyadenylation. hdm365 precedes full-length hdm2 RNA expression after induction by p53 and accumulates to significant levels in the nucleus, detectable at the site of hdm2 transcription and processing only. Considering a 10-fold lower stability and high steady-state levels of the novel RNA species, hdm365 appears to be the major processing product of hdm2 transcripts. hdm365 induction was observed after ectopic expression of p53 and after DNA damaging treatment of tumor cell lines, primary fibroblasts and lymphocytes, and was not related to apoptosis. Corresponding truncated transcripts were observed in hdm2 amplified cells. High stress-inducible expression levels, absence of a corresponding protein, and nuclear localisation of hdm365 suggest a novel RNA-based function for hdm2.

Alternative splicing of caspase-8 mRNA during differentiation of human leukocytes

Caspase-8 is a key initiator of death receptor-induced apoptosis. Here we provide evidence that caspase-8 expression is subject to posttranscriptional regulation in human leukocytes. Resting peripheral blood lymphocytes preferentially use a distant splice donor site at the 3'-end of caspase-8 exon 8 to generate mRNAs with a truncated open reading frame. When lymphocytes were activated, the expression of caspase-8 variants was shifted to caspase-8/a and b which lack the extension of exon 8. The opposite change of the splicing pattern was found in a neutrophil differentiation model. Promyelocytic HL-60 cells mainly expressed caspase-8 mRNAs with the normal exon 8, but the splicing pattern was changed to the distant exon 8 splice site during DMSO-induced differentiation of HL-60 cells. In spite of the presence of these novel mRNAs, the corresponding translation products were not detectable in either cell type. Our findings suggest that leukocyte differentiation and alternative splicing of caspase-8 pre-mRNA are inter-dependent processes.

Terminal differentiation of human keratinocytes and stratum corneum formation is associated with caspase-14 activation

Programmed cell death of epidermal keratinocytes (KC) results in the formation of cornified cells, which constitute the outermost skin layer, the stratum corneum. Here we show by reverse transcription-polymerase chain reaction, western blot, and immunohistochemistry that epidermal KC express caspase-14, a member of the caspase family of pro-apoptotic proteases, in a tissue-specific manner. Caspase-14 protein abundance strongly increases during terminal differentiation of KC in vivo and in vitro. Under conditions that lead to stratum corneum formation caspase-14 cleavage products, which indicate proenzyme activation, appeared in the KC lysates. Cleavage of the enzyme was also detected in lysates from normal human epidermis and in extracts of stratum corneum. Our findings demonstrate that caspase-14 is activated during KC differentiation and strongly suggest that it is involved in the formation of the human skin barrier.J Invest Dermatol 115:1148-1151 2000

Molecular mechanisms involved in the antiproliferative action of protein tyrosine phosphatase inhibitor potassium bisperoxo(1,10-phenanthroline)oxovanadate

Potassium bisperoxo(1,10-phenanthroline)oxovanadate, bpV(phen), a powerful protein phosphotyrosine phosphatase inhibitor and a potent insulinomimetic, influenced three fundamental cellular processes in HL-60 human leukemic cells: 1) inhibition of proliferation, 2) induction of differentiation and 3) apoptotic cell death. In the presence of micromolar concentrations of bpV(phen) cell number and DNA synthesis decreased progressively with time of incubation. A single treatment with bpV(phen) (3 microM) activated a differentiation program; after 6 days of incubation 82% of cells were differentiated, but differentiation started already within the first 24 h. Concentrations of 5-10 microM bpV(phen) caused the characteristic DNA ladder pattern, starting after 4.5 h. Differentiation in HL-60 cells appear to be associated with activation of extracellular signal-regulated kinase while apoptosis is connected with phosphorylation and activation of both extracellular signal-regulated kinase and c-Jun N-terminal kinase in a concentration and time-dependent manner. The antiproliferative and apoptotic action of bpV(phen) could be exploited in combination chemotherapy in leukemia.

Caspase-14: analysis of gene structure and mRNA expression during keratinocyte differentiation

Caspase-14 is expressed in a tissue-specific manner in mouse skin. Here we determined the complete caspase-14 cDNA sequence of human caspase-14 by rapid amplification of cDNA ends. Sequence comparison with a cosmid clone containing genomic DNA revealed that the human caspase-14 gene comprises seven exons. Facultative utilization of a cryptic splice acceptor site within intron 5 leads to the formation of two mRNA species. In situ hybridization of human skin showed that caspase-14 is expressed in the uppermost layer of living epidermal cells, i.e., the granular layer, in hair follicles and sebaceous glands. In vitro caspase-14 transcription was low in subconfluent cultures but strongly increased when keratinocyte differentiation was simulated by maintaining cells at confluence for several days. This transcriptional upregulation was suppressed in the presence of a high extracellular calcium concentration. Our findings show that caspase-14 is regulated at the level of transcription during keratinocyte differentiation in vitro and in vivo.

Keratinocytes express the CD146 (Muc18/S-endo) antigen in tissue culture and during inflammatory skin diseases

The CD146 (or MUC18/MEL-CAM) antigen is a cell adhesion molecule of the immunoglobulin superfamily. Besides in melanoma, expression of CD146 antigen has been demonstrated in breast epithelia and hair follicles. We studied its expression by human keratinocytes in culture as well as in neoplastic and inflammatory skin diseases. Staining of primary cultured keratinocytes revealed expression of CD146 on the cell membrane, preferentially on cell-cell contact sites. Western blot analysis of keratinocytes detected a band of approximately 113 kDa, corresponding to the CD146 protein. In contrast to primary keratinocytes, neither CD146 protein nor mRNA expression was found in the keratinocyte-derived cell lines A431 and HaCaT. Treatment of keratinocytes with the proinflammatory cytokines interleukin-1 and interleukin-6, tumor necrosis factor-alpha, and interferon-gamma, resulted in no change of CD146 expression and incubation with phorbol 12-myristate 13-acetate led to a reduction of CD146 on keratinocytes. By contrast, when culturing keratinocytes in medium devoid of growth supplements, a distinct upregulation was observed as compared with culture in fully supplemented medium. In normal human epidermis expression of the CD146 antigen was not detectable. It was strongly upregulated, however, on suprabasal keratinocytes in psoriasis, in lichen planus, in the epidermis overlying skin neoplasms, and in viral warts. In squamous cell carcinomas and basal cell carcinomas only a minority of tumor cells expressed CD146. Our findings suggest that the CD146 antigen represents an activation marker of keratinocytes and may be involved in cutaneous inflammatory tissue reaction.

Melanin binds reversibly to thermostable DNA polymerase and inhibits its activity

We found that both RNA and cDNA preparations derived from melanocytes contain a RT-PCR inhibitor that copurified with nucleic acids. Investigation of the candidate inhibitor melanin revealed that it potently blocks PCR at concentrations below 200 ng/ml, whereas 100 microg/ml melanin was required to inhibit reverse transcription. Melanin and thermostable DNA polymerase preferentially formed a distinct complex with reduced migration velocity as compared to pure polymerase in nondenaturating polyacrylamide gel electrophoresis. The inhibition of the enzyme by melanin could be reversed by diluting solutions of preformed complexes or by adding excess amounts of other proteins such as bovine serum albumin or dry milk. Our findings demonstrate that melanin is a potent inhibitor of thermostable DNA polymerase in vitro and that the inhibitory effect is conferred by a direct and reversible polymerase-melanin interaction.

Characterization of a cDNA clone, encoding a 70 kDa heat shock protein from the dermatophyte pathogen Trichophyton rubrum

Trichophyton rubrum is an anthropophilic fungus causing up to 90% of chronic cases of dermatophytosis. To characterize T. rubrum proteins at the molecular level, we established a cDNA library of this pathogen. Here we describe a recombinant cDNA clone identical to eukaryotic 70kDa heat-shock proteins (HSPs). Western blot analysis using an anti HSP70 monoclonal antibody detected a recombinant fusion protein in Escherichia coli transformed with the expression vector containing the cloned cDNA insert. Southern blot analysis of T. rubrum genomic DNA detected no other members of the HSP70 gene family. Further analysis revealed the presence of two introns within the ORF of the HSP70 gene. In Northern blot analysis, the cDNA clone was hybridized to a RNA species of about 3.5kb which was constitutively expressed by cells cultured at 27 degrees C and was strongly up-regulated after culture at 37 degrees C. In summary, we have cloned the first member of the HSP family of dermatophytes and characterized it as a member of the Dnak subfamily of 70kDa HSPs.

The human homologue of the bovine leukemia virus receptor BLVRcp1 is the delta-subunit of adaptor-related AP-3 protein that does not bind the BVLgp51

The relationship between the putative bovine leukemia virus receptor gene (BVLRcp) and the susceptibility of human cells to BLV infection was studied. Three cDNA clones encoding different portions of the human equivalent of bovine BLVRcp1 were isolated by DNA-DNA hybridization by comparison of the human cDNA clones to bovine BLVRcp1. Amino acid sequence indicated that the human sequence encodes the delta subunit of the AP-3 adaptor-related protein. When the recombinant human homologue BLVRcp2 was expressed in E. coli, it failed to bind the BLVgp51. However, the BVLVgp51 binding ability was restored when the chimerical BLVRcp molecule was prepared by exchanging 5' ends between bovine and human BLVRcp cDNAs. This finding implies that this BLVgp51 binding site is present only on the bovine BLVRcp and therefore its human homologue cannot be recognized by BLVgp51. This might also explain the resistance of human cells to BLV infection.

The cell death regulatory protein bak is expressed in endothelial cells in inflamed tissues and Is induced by IFN-gamma in vitro

In the present report, we examined the endothelial expression of the anti- and pro-apoptotic proteins Bcl-2 and Bak in situ and in vitro. Endothelial cells (EC) in regular tissue of the bowel and the skin were essentially negative for both Bcl-2 and Bak. In contrast, EC within the walls of fistulas and abscesses in these organs stained distinctly for Bak, but remained Bcl-2-negative. In tissue culture both unstimulated human dermal microvascular endothelial cells (HDMEC) and human umbilical vein endothelial cells (HUVEC) expressed Bcl-2 and Bak constitutively. Exposure of EC to 200-1000 IU IFN-gamma downregulated Bcl-2 but upregulated Bak. This opposing regulation of Bcl-2 and Bak in vitro and the expression of Bak in EC adjacent to necrotic tissue areas suggests that this pro-apoptotic protein may play a decisive role in regulation of EC survival in vivo.

UVA and UVB radiation differentially regulate vascular endothelial growth factor expression in keratinocyte-derived cell lines and in human keratinocytes

Vascular endothelial growth factor (VEGF) is a central regulator of neoangiogenesis in inflammatory and neoplastic conditions. Ultraviolet irradiation is one of the mainstays of dermatological therapy for various inflammatory skin diseases. In the present study we have compared the effects of UV irradiation on the production of VEGF by keratinocytes (KC) and by the KC-derived cell lines A431 and HaCaT. Irradiation of A431 and HaCaT cells with both UVA (10 J/cm2 and 20 J/cm2) and UVB (8 mJ/cm2 and 16 mJ/cm2) led to strong upregulation of VEGF mRNA and protein. Induction of VEGF by UVA and UVB in these cells was mediated by different pathways, i.e. the generation of free radicals and the secretion of (a) soluble factor(s), respectively. Unlike KC-derived cell lines, no increase in VEGF production was observed in KC in primary culture after irradiation with the same UV doses. Increasing the irradiation dose in these cells of UVA to 40 J/cm2 led to a marked decrease in soluble VEGF, whereas doses as high as 32 mJ/cm2 UVB only minimally affected VEGF levels. Reduction of VEGF production by KC might contribute to the effect of UVA irradiation in inflammatory skin diseases. The differential response of primary KC and autonomously growing KC-derived cell lines to the induction of VEGF by UV light could favor neoangiogenesis in the vicinity of epidermal tumor cells in vivo, thereby endowing them with a growth advantage over normal cells.

Activation of MAPK by potassium bisperoxo(1,10-phenanthroline)oxovanadate (V)

Potassium bisperoxo(1,10-phenantroline)oxovanadate (V) [bpV(phen)] is a potent protein tyrocine phosphatase inhibitor which mediates a variety of biological effects. The aim of these studies was to examine the role(s) of mitogen activated protein kinase (MAPK) pathways in PC12 cell proliferation and toxicity by bpV(phen). BpV(phen) exerts a bimodal effect in PC12 cells: proliferation at low and cell death at higher micromolar concentrations. Activation of MAPK by bpV(phen) depends on time and concentration. The phosphorylation pattern of extracellular regulated kinases (ERK 1/2), c-jun N-terminal activated kinases (JNK) and p38 in PC12 cells is strikingly different. Activation of JNK is sustained in PC12 cells. In contrast, ERK 1/2 activation is transient and treatment with PD98059 indicates that ERK activation by bpV(phen) is partly independent from the ras-MEK pathway. Stability studies of bpV(phen) in DMEM and PBS showed linear relationship with T1/2 about 6 h and 10 days in DMEM and PBS, respectively. Comparison between the time courses of MAPK activation and kinetics of bpV(phen) decomposition as assessed by 51V-NMR analysis show that the initial and maximal phosphorylation signals are produced in the presence of the complex bpV(phen) and not caused by the decomposition products of bpV(phen).

Reverse transcription-polymerase chain reaction products of alternatively spliced mRNAs form DNA heteroduplexes and heteroduplex complexes

Reverse transcription-polymerase chain reaction (RT-PCR) is frequently used to simultaneously detect mRNA isoforms, which are generated by alternative splicing. Here we characterize two previously unrecognized RT-PCR products of vascular endothelial growth factor (VEGF) RNA. DNA products with apparent sizes of 600 and 1200 base pairs (bp) were detected at high cycle numbers. Heat denaturation of the smaller product and subsequent reannealing revealed that it was a heteroduplex consisting of two different DNA strands. These were identified by DNA sequencing as the amplification products of two VEGF transcripts, i.e. VEGF121 and VEGF165, which differ by the presence of one exon. S1 nuclease analysis showed that this exon is bulged out as a single-stranded loop. Purified heteroduplexes in solution were found to form a 1200-bp DNA product which could be reconverted into 600-bp DNA heteroduplexes by mild denaturation at 70 degreesC. These findings suggest that this product is formed by base pairing of complementary heteroduplex loops and represents a novel four-stranded DNA structure.