The influence of precompression on elasticity of thyroid nodules estimated by ultrasound shear wave elastography.

OBJECTIVES: To investigate the influence of variations in resting pressure (precompression) on thyroid ultrasound supersonic shear wave elastography (SWE). METHODS: Thirty-five normal thyroid glands (Norm), 55 benign hyperplastic nodules (BHN), and 17 papillary thyroid cancers (PTC) in 96 subjects underwent thyroid SWE. Four precompression levels were applied manually by the operator, ranging from A (baseline, 0 % strain) to D (high, 22-30 % strain). SWE results at each precompression level were compared using ANOVA tests with P < 0.05 indicating significance. RESULTS: SWE indices were highest in PTC, followed by BHN and Norm at each precompression level (P < 0.05). All tissue types showed successive increases in SWE results as precompression increased, although the rate was higher for PTC than BHN and Norm (Ps < 0.05). SWE values (kPa) of Norm, BHN, and PTC at baseline precompression (A) were 10.3 ± 3.3, 17.7 ± 7.6, and 22.2 ± 11.9 compared with 21.1 ± 4.2, 42.3 ± 16.0, and 97.6 ± 46.8 at high precompression (D). SWE index differences between precompression levels A and D were 10.8 kPa for Norm, 24.6 kPa for BHN, and 75.4 kPa for PTC. CONCLUSION: PTCs show greater SWE stiffening than BHN as precompression rises. Precompression effects on thyroid nodules are not negligible and may account for wide discrepancies in published SWE discriminatory performance results for thyroid malignancy. KEY POINTS: • Increases in resting pressure (precompression) applied by the operator increases thyroid stiffness. • Papillary cancers show greater increases in stiffness (strain hardening) than benign nodules. • Precompression may affect the diagnostic performance of shearwave elastography for thyroid malignancy.

The multiple stressor effect in zebrafish embryos from simultaneous exposure to ionising radiation and cadmium.

Living organisms are exposed to a mixture of environmental stressors, and the resultant effects are referred to as multiple stressor effects. In the present work, we studied the multiple stressor effect in embryos of the zebrafish (Danio rerio) from simultaneous exposure to ionising radiation (alpha particles) and cadmium through quantification of apoptotic signals at 24 h postfertilisation (hpf) revealed by vital dye acridine orange staining. For each set of experiments, 32-40 dechorionated embryos were deployed, which were divided into four groups each having 8-10 embryos. The four groups of embryos were referred to as (1) the control group (C), which received no further treatments after dechorionation; (2) the Cd-dosed and irradiated group (CdIr), which was exposed to 100 µM Cd from 5 to 24 hpf, and also received about 4.4 mGy from alpha particles at 5 hpf; (3) the irradiated group (Ir), which received about 4.4 mGy from alpha particles at 5 hpf; and (4) the Cd-dosed group (Cd), which was exposed to 100 µM Cd from 5 to 24 hpf. In general, the CdIr, Ir and Cd groups had more apoptotic signals than the C group. Within the 12 sets of experimental results, two showed significant synergistic effects, one showed a weakly synergistic effect and nine showed additive effects. The multiple stressor effect of 100 µM Cd with ~4.4 mGy alpha-particle radiation resulted in an additive or synergistic effect, but no antagonistic effect. The failure to identify significant synergistic effects for some sets of data, and thus their subsequent classification as additive effects, might be a result of the relatively small magnitude of the synergistic effects. The results showed that the radiation risk could be perturbed by another environmental stressor such as a heavy metal, and as such a realistic human radiation risk assessment should in general take into account the multiple stressor effects.

Testing the possible negative association of type 1 diabetes and atopic disease by analysis of the interleukin 4 receptor gene.

Variations in the interleukin 4 receptor A (IL4RA) gene have been reported to be associated with atopy, asthma, and allergy, which may occur less frequently in subjects with type 1 diabetes (T1D). Since atopy shows a humoral immune reactivity pattern, and T1D results from a cellular (T lymphocyte) response, we hypothesised that alleles predisposing to atopy could be protective for T1D and transmitted less often than the expected 50% from heterozygous parents to offspring with T1D. We genotyped seven exonic single nucleotide polymorphisms (SNPs) and the -3223 C>T SNP in the putative promoter region of IL4RA in up to 3475 T1D families, including 1244 Finnish T1D families. Only the -3223 C>T SNP showed evidence of negative association (P=0.014). There was some evidence for an interaction between -3233 C>T and the T1D locus IDDM2 in the insulin gene region (P=0.001 in the combined and P=0.02 in the Finnish data set). We, therefore, cannot rule out a genetic effect of IL4RA in T1D, but it is not a major one.

Cobblestone area-forming cells, long-term culture-initiating cells and NOD/SCID repopulating cells in human neonatal blood: a comparison with umbilical cord blood.

Our prior study demonstrated that neonatal blood (NB) contained hematopoietic stem and progenitor cells that declined rapidly after birth. To validate that NB is a source of functional stem cells, we characterized this population in terms of cobblestone area-forming cells (CAFC), long-term culture-initiating cells (LTC-IC) and NOD/SCID mouse repopulating cells (SRC) in NB and umbilical cord blood (CB). Our data demonstrated that the frequencies of CAFC (30.2 vs 37.1, P = 0.14) and LTC-IC (28.6 vs 31.0, P = 0.49) in 1 x 10(5) mononuclear cells (MNC) of NB and CB were similar, suggesting that these cells were preserved in the circulation of the neonates shortly after birth. Sublethally irradiated NOD/SCID mice were transplanted with CD34(+) cells enriched from thawed NB and CB. At 6 weeks post transplant, human (hu)CD45(+) cells were detected in the bone marrow (BM), spleen and peripheral blood (PB) of the mice as demonstrated by flow cytometric and DNA analysis. Levels of huCD45(+)cells and colony forming units (CFU) appeared to be dependent on the infusion cell dose and were higher in animals receiving CB cells when compared with those of the NB group. The transplanted cells were capable of differentiation into multi-lineage progenitor cells (CD34(+) cells and differential CFU), as well as mature myeloid (CD14(+), CD33(+)), B lymphoid (CD19(+)) and megakaryocytic (CD61(+)) cells in the recipients. NB cells, subjected to ex vivo culture in an optimized preclinical condition, were significantly expanded to early and committed progenitor cells. Expanded NB contained SRC at a reduced quantity but with high proportions of CD14(+) cells and CD33(+) cells. Our study confirms that NB contains pluripotent hematopoietic stem and progenitor cells capable of homing and engrafting the NOD/SCID mice.

Polymorphic proteins of Chlamydia spp.--autotransporters beyond the Proteobacteria.

Gram-negative bacteria secrete a variety of proteins to the cell surface and beyond, a process with many inherent difficulties. An exceptionally widespread answer to these problems is the type V (or autotransporter) secretion pathway. By exploiting the data made available by bacterial genome sequencing, we have discovered that the previously described polymorphic proteins of Chlamydia spp. resemble members of the autotransporter family, and we suggest that they follow the same secretion pathway.

An abundance of bacterial ADP-ribosyltransferases--implications for the origin of exotoxins and their human homologues.

ADP-ribosylation is a post-translational modification that can be seen in many contexts, including as the primary mechanism of action of many important bacterial exotoxins. By data-mining complete and incomplete bacterial genome sequences, we have discovered >20 novel putative ADP-ribosyltransferases, including several new potential toxins.

Platelet-derived growth factor enhances granulopoiesis via bone marrow stromal cells.

Platelet-derived growth factor (PDGF), a growth factor for connective tissue cells, stimulates erythropoiesis and megakaryocytopoiesis in vitro but the effect of PDGF on granulocyte proliferation remains unknown. The effect of the recombinant human PDGF-BB isoform on granulopoiesis was investigated in this study. The results show that PDGF significantly stimulated murine colony-forming unit-granulocyte-monocyte (CFU-GM) proliferation in a dose-dependent manner (1 to 100 ng/mL) using murine bone marrow cells (n = 4). Maximum stimulation was obtained with 50 ng/mL of PDGF (P < .01). The effect of PDGF on murine CFU-GM proliferation was compared with that of interleukin (IL)-3, IL-6, granulocyte-monocyte colony-stimulating factor (GM-CSF), and acidic fibroblast growth factor (aFGF) at their optimal doses. The stimulating activity of PDGF was higher than that of aFGF but lower than that of IL-3, IL-6, or GM-CSF. There is no synergistic effect between PDGF and IL-3 or IL-6, but a significant enhancing effect was observed in IL-3 plus IL-6. PDGF also stimulated the growth of CFU-GM with CFU-megakaryocyte in the presence of bone marrow stromal cells. We also found that PDGF had similar a effect on human CFU-GM proliferation using bone marrow mononuclear cells (MNC). However, the increase in PDGF-stimulated CFU-GM proliferation was inhibited by anti-GM-CSF, anti-IL-3, and anti-IL-6 antibodies (n = 4), suggesting that endogenously produced GM-CSF, IL-3, and IL-6 may play a role in the PDGF-induced CFU-GM proliferation. Furthermore, PDGF (1 to 100 ng/mL) did not show any effect on CFU-GM proliferation when replacing bone marrow MNC with immunomagnetic selection-enriched CD34+ cells from human cord blood (n = 5; purity, 91% +/- 6.5%). This study indicates that PDGF may indirectly enhance CFU-GM proliferation by inducing the bone marrow stromal cells to produce GM-CSF, IL-3, or IL-6.

An embarrassment of sortases - a richness of substrates?

A range of surface proteins is anchored to the cell walls of Gram-positive pathogens such as Staphylococcus aureus by the transpeptidase sortase. Until now, sortase-like proteins and their substrates appeared to be limited mainly to such pathogens. However, by searching for sortase homologues among complete and incomplete genome sequences, we have found them to be present in almost all Gram-positives, a single Gram-negative bacterium and an archaean. There is usually more than one sortase-like protein encoded in each Gram-positive genome, and the genes encoding the sortase-like proteins are often clustered with genes encoding their likely substrates.

Tricorn-like proteases in bacteria.

The tricorn protease is an archaeal protease that forms massive proteasome-like capsids with a hollow chamber. beta-Propeller and PDZ domains are thought to play a role in substrate selection. By analysis of predicted proteins from novel bacterial genome sequences, we have identified four new bacterial tricorn-like proteases, complete with similar beta-propeller, PDZ and catalytic domains. We propose various hypotheses as to the function of these domains that can now be tested in the laboratory.

Preclinical ex vivo expansion of cord blood hematopoietic stem and progenitor cells: duration of culture; the media, serum supplements, and growth factors used; and engraftment in NOD/SCID mice.

BACKGROUND: Ex vivo expansion of cord blood (CB) hematopoietic stem and progenitor cells increases cell dose and may reduce the severity and duration of neutropenia and thrombocytopenia after transplantation. This study's purpose was to establish a clinically applicable culture system by investigating the use of cytokines, serum-free media, and autologous plasma for the expansion of CB cells and the engraftment of expanded product in nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice. STUDY DESIGN AND METHODS: Enriched CB CD34+ cells were cultured in four media (Iscove's modified Dulbecco's medium with FCS, Gibco; X-Vivo-10, BioWhittaker; QBSF-60, Quality Biological; and StemSpan SFEM, Stem Cell Technologies) with four cytokine combinations (thrombopoietin [TPO], SCF, Flt-3 ligand [FL] with and without G-CSF, and/or IL-6). The effect of autologous CB plasma was also investigated. The read-out measures were evaluated on Days 8 and 12. After expansion at the optimized condition, cultured cells were transplanted into sublethally irradiated NOD/SCID mice. The engraftment of human CD45+ cells and subsets in the bone marrow, spleen, and peripheral blood was determined. RESULTS: QBSF-60 or StemSpan SFEM supported high yields of early progenitors (CD34+ cells,

Effects of flt-3 ligand in combination with TPO on the expansion of megakaryocytic progenitors.

As an early acting growth factor, flt-3 ligand (FL) promotes the ex vivo expansion of hematopoietic stem and progenitor cells. The effect and mechanism of FL on the development of the megakaryocytic lineage remain unclear. In this study, we compared the effects of FL and stem cell factor (SCF) in combination with other megakaryocyte-promoting cytokines on the differentiation and proliferation of megakaryocytic progenitors and investigated the expression of flt-3 receptors on megakaryocytic cell lines. In liquid cultures of enriched CD34+ cells from human umbilical cord blood for 14 days, FL plus thrombopoietin (TPO), interleukin-3 (IL-3), and IL-6 promoted the expansion of nucleated cells, CD34+ cells, CD34+ CD38- cells, and megakaryocyte colony-forming units (CFU-MK) by 300 +/- 115-, 23.8 +/- 11.3-, 33.9 +/- 28.6-, and 584 +/- 220-fold, respectively. Replacing FL with SCF significantly decreased the yield of all cell types. Using murine bone marrow (BM) cells, we demonstrated that FL at a range of 0-100 ng/ml had no significant mitogenic effect on CFU-MK formation. TPO increased CFU-MK (p < 0.001) but the effect was not significantly modified by FL. While one human acute lymphoblastic leukemia sample expressed high levels of flt-3 receptor, the four megakaryocytic cell lines (Meg-01, CHRF-288-11, M-07e, and Dami) did not show any positive expression. Our data suggest that the present cytokine combination and expansion conditions provide an effective and potentially useful system for the clinical expansion of cord blood for bone marrow transplantation (BMT). FL alone did not stimulate megakaryocytopoiesis, possibly due to the lack of receptor expression on megakaryocytes. The effect of FL in augmenting the expansion of CFU-MK in liquid culture might be due to the early action of FL at the pluripotent stem cell stage.

Decrease in skin-closing tension intraoperatively with suture tension adjustment reel, balloon expansion, and undermining.

BACKGROUND: The biomechanical and viscoelastic properties of the skin enable it to be significantly stretched within a relatively short period of time. This property, called mechanical creep, is exploited in various surgical maneuvers for intraoperative closure of large surgical defects. The recently introduced Miami Suture Tension Adjustment Reel (S.T.A.R.) device permits both the precise sutured attachment of a linear cycled load to approximate the edges of widened surgical defects, and the easy measurement of wound edge tension across the defects. OBJECTIVE: It was our purpose to compare the relative effects of linear load cycling with the S.T.A.R. device, spherical load cycling with balloon expander, and surgical undermining on the closing tension of surgical defects. METHOD: Surgical wounds were created on the flanks of six pigs and these defects were closed by various methods of repair. The combination of undermining and the S.T.A.R. device ws also evaluated. RESULTS: The average total decreases in skin closing tension were: undermining, 17.8 +/- 0.5%; balloon, 28.5 +/- 1.6%; S.T.A.R. device, 36.6 +/- 4.8%. CONCLUSION: Our data showed that all three techniques were effective in lowering the tension required to approximate surgically created defects, with the S.T.A.R. device proving to be most effective. Undermining and the S.T.A.R. device also worked synergistically to decrease skin-closing tension.