Synovial tissue in rheumatoid arthritis is a source of osteoclast differentiation factor

OBJECTIVE

Osteoclast differentiation factor (ODF; also known as osteoprotegerin ligand, receptor activator of nuclear factor kappaB ligand, and tumor necrosis factor-related activation-induced cytokine) is a recently described cytokine known to be critical in inducing the differentiation of cells of the monocyte/macrophage lineage into osteoclasts. The role of osteoclasts in bone erosion in rheumatoid arthritis (RA) has been demonstrated, but the exact mechanisms involved in the formation and activation of osteoclasts in RA are not known. These studies address the potential role of ODF and the bone and marrow microenvironment in the pathogenesis of osteoclast-mediated bone erosion in RA.

METHODS

Tissue sections from the bone-pannus interface at sites of bone erosion were examined for the presence of osteoclast precursors by the colocalization of messenger RNA (mRNA) for tartrate-resistant acid phosphatase (TRAP) and cathepsin K in mononuclear cells. Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to identify mRNA for ODF in synovial tissues, adherent synovial fibroblasts, and activated T lymphocytes derived from patients with RA.

RESULTS

Multinucleated cells expressing both TRAP and cathepsin K mRNA were identified in bone resorption lacunae in areas of pannus invasion into bone in RA patients. In addition, mononuclear cells expressing both TRAP and cathepsin K mRNA (preosteoclasts) were identified in bone marrow in and adjacent to areas of pannus invasion in RA erosions. ODF mRNA was detected by RT-PCR in whole synovial tissues from patients with RA but not in normal synovial tissues. In addition, ODF mRNA was detected in cultured adherent synovial fibroblasts and in activated T lymphocytes derived from RA synovial tissue, which were expanded by exposure to anti-CD3.

CONCLUSION

TRAP-positive, cathepsin K-positive osteoclast precursor cells are identified in areas of pannus invasion into bone in RA. ODF is expressed by both synovial fibroblasts and by activated T lymphocytes derived from synovial tissues from patients with RA. These synovial cells may contribute directly to the expansion of osteoclast precursors and to the formation and activation of osteoclasts at sites of bone erosion in RA.

Identification of CD72 as a lymphocyte receptor for the class IV semaphorin CD100: a novel mechanism for regulating B cell signaling

We have identified the lymphocyte semaphorin CD100/Sema4D as a CD40-inducible molecule by subtractive cDNA cloning. CD100 stimulation significantly enhanced the effects of CD40 on B cell responses. Administration of soluble CD100 markedly accelerated in vivo antigen-specific antibody responses. CD100 receptors with different binding affinities were detected on renal tubular cells (K(d) = approximately 1 x 10(-9)M) and lymphocytes (K(d) = approximately 3 x 10(-7)M). Expression cloning revealed that the CD100 receptor on lymphocytes is CD72, a negative regulator of B cell responsiveness. CD72 thus represents a novel class of semaphorin receptors. CD100 stimulation induced tyrosine dephosphorylation of CD72 and dissociation of SHP-1 from CD72. Our findings indicate that CD100 plays a critical role in immune responses by the novel mechanism of turning off negative signaling by CD72.

Virologic factors associated with failure to passive-active immunoprophylaxis in infants born to HBsAg-positive mothers

In infants born to hepatitis B surface antigen (HBsAg)-positive mothers, failure after passive-active immunization still occurs. The role of maternal hepatitis B DNA level and other risk factors in this setting remains unclear. This study retrospectively evaluated virologic and other risk factors associated with immunoprophylaxis failure in infants born to HBsAg-positive mothers. Between January 2007 and March 2010, we reviewed the clinical and virologic tests in 869 mother-infant pairs. All infants received the identical passive-active immunization schedule after birth. The failure infants (HBsAg positive at 7-12 months of age) were compared to infants who were HBsAg negative when tested during this time period. Among 869 infants, 27 (3.1%) infants were immunoprophylaxis failures and the other 842 (96.9%) infants remained HBsAg negative. When mothers' pre-delivery HBV DNA levels were stratified to <6, 6-6.99, 7-7.99 and ≥ 8 log(10) copies/mL, the corresponding rates of immunoprophylaxis failure were 0%, 3.2% (3/95), 6.7% (19/282) and 7.6% (5/66), respectively (P < 0.001 for the trend). All failure infants were born to hepatitis B e antigen (HBeAg)-positive mothers. Multivariate logistic regression analysis identified maternal HBV DNA levels [odds ratio (OR) = 1.88, 95% confidence interval (CI): 1.07-3.30] and detectable HBV DNA in the cord blood (OR = 39.67, 95% CI: 14.22-110.64) as independent risk factors for immunoprophylaxis failure. All failure infants were born to HBeAg-positive mothers with HBV DNA levels ≥ 6 log(10) copies/mL. The presence of HBV DNA in cord blood predicted failure to passive-active immunization.

MiR-200b and miR-15b regulate chemotherapy-induced epithelial-mesenchymal transition in human tongue cancer cells by targeting BMI1

Chemotherapy has been reported to induce epithelial-mesenchymal transition (EMT) in tumor cells, which is a critical step in the process of metastasis leading to cancer spreading and treatment failure. However, the underlying mechanisms of chemotherapy-induced EMT remain unclear, and the involvement of microRNAs (miRNA) in this process is poorly understood. To address these questions, we established stable chemotherapy-resistant tongue squamous cell carcinoma (TSCC) cell lines CAL27-res and SCC25-res by exposing the parental CAL27 and SCC25 lines to escalating concentrations of cisplatin for 6 months. CAL27-res and SCC25-res cells displayed mesenchymal features with enhanced invasiveness and motility. MiRNA microarray illustrated that miR-200b and miR-15b were the most significantly downregulated microRNAs in CAL27-res cells. Ectopic expression of miR-200b and miR-15b with miRNA mimics effectively reversed the phenotype of EMT in CAL27-res and SCC25-res cells, and sensitized them to chemotherapy, but inhibition of miR-200b and miR-15b in the sensitive lines with anti-sense oligonucleotides induced EMT and conferred chemoresistance. Retrieving the expression of B lymphoma Mo-MLV insertion region 1 homolog (BMI1), a target for miR-200b and miR-15b, in the presence of the miRNA mimics by transfecting CAL27-res cells with pcDNA3.1-BMI1-carrying mutated seed sequences of miR-200b or miR-15b at its 3'-UTR recapitulated chemotherapy-induced EMT. In vivo, enforced miR-200b or miR-15b expression suppressed metastasis of TSCC xenografts established by CAL27-res cells. Clinically, reduced miR-200b or miR-15b expression was associated with chemotherapeutic resistance in TSCCs and poor patient survival. Our data suggest that reduced expression of miR-200b and miR-15b underscores the mechanisms of chemotherapy-induced EMT in TSCC, and may serve as therapeutic targets to reverse chemotherapy resistance in tongue cancers.

Ligand-stabilized ruthenium nanoparticles: synthesis, organization, and dynamics

The decomposition of the ruthenium precursor Ru(COD)(COT) (1, COD = 1,5-cyclooctadiene; COT = 1,3,5-cyclooctatriene) in mild conditions (room temperature, 1--3 bar H(2)) in THF leads, in the presence of a stabilizer (polymer or ligand), to nanoparticles of various sizes and shapes. In THF and in the presence of a polymer matrix (Ru/polymer = 5%), crystalline hcp particles of uniform mean size (1.1 nm) homogeneously dispersed in the polymer matrix and agglomerated hcp particles (1.7 nm) were respectively obtained in poly(vinylpyrrolidone) and cellulose acetate. The same reaction, carried out using various concentrations relative to ruthenium of alkylamines or alkylthiols as stabilizers (L = C(8)H(17)NH(2), C(12)H(25)NH(2), C(16)H(33)NH(2), C(8)H(17)SH, C(12)H(25)SH, or C(16)H(33)SH), leads to agglomerated particles (L = thiol) or particles dispersed in the solution (L = amine), both displaying a mean size near 2--3 nm and an hcp structure. In the case of amine ligands, the particles are generally elongated and display a tendency to form worm- or rodlike structures at high amine concentration. This phenomenon is attributed to a rapid amine ligand exchange at the surface of the particle as observed by (13)C NMR. In contrast, the particles stabilized by C(8)H(17)SH are not fluxional, but a catalytic transformation of thiols into disulfides has been observed which involves oxidative addition of thiols on the ruthenium surface. All colloids were characterized by microanalysis, infrared spectroscopy after CO adsorption, high-resolution electron microscopy, and wide-angle X-ray scattering.

Phosphorylation-mediated activation of LDHA promotes cancer cell invasion and tumour metastasis

Metastases remain the major cause of death from cancer. Recent molecular advances have highlighted the importance of metabolic alterations in cancer cells, including the Warburg effect that describes an increased glycolysis in cancer cells. However, how this altered metabolism contributes to tumour metastasis remains elusive. Here, we report that phosphorylation-induced activation of lactate dehydrogenase A (LDHA), an enzyme that catalyses the interconversion of pyruvate and lactate, promotes cancer cell invasion, anoikis resistance and tumour metastasis. We demonstrate that LDHA is phosphorylated at tyrosine 10 by upstream kinases, HER2 and Src. Targeting HER2 or Src attenuated LDH activity as well as invasive potential in head and neck cancer and breast cancer cells. Inhibition of LDH activity by small hairpin ribonucleic acid or expression of phospho-deficient LDHA Y10F sensitized the cancer cells to anoikis induction and resulted in attenuated cell invasion and elevated reactive oxygen species, whereas such phenotypes were reversed by its product lactate or antioxidant N-acetylcysteine, suggesting that Y10 phosphorylation-mediated LDHA activity promotes cancer cell invasion and anoikis resistance through redox homeostasis. In addition, LDHA knockdown or LDHA Y10F rescue expression in human cancer cells resulted in decreased tumour metastasis in xenograft mice. Furthermore, LDHA phosphorylation at Y10 positively correlated with progression of metastatic breast cancer in clinical patient tumour samples. Our findings demonstrate that LDHA phosphorylation and activation provide pro-invasive, anti-anoikis and pro-metastatic advantages to cancer cells, suggesting that Y10 phosphorylation of LDHA may represent a promising therapeutic target and a prognostic marker for metastatic human cancers.

Adaptive modification of treatment planning to minimize the deleterious effects of treatment setup errors

PURPOSE

Using daily setup variation measured from an electronic portal imaging device (EPID), radiation treatment of the individual patient can be adaptively reoptimized during the course of therapy. In this study, daily portal images were retrospectively examined to: (a) determine the number of initial days of portal imaging required to give adequate prediction of the systematic and random setup errors; and (b) explore the potential of using the prediction as feedback to reoptimize the individual treatment part-way through the treatment course.

METHODS AND MATERIALS

Daily portal images of 64 cancer patients, whose treatment position was not adjusted during the course of treatment, were obtained from two independent clinics with similar setup procedures. Systematic and random setup errors for each patient were predicted using different numbers of initial portal measurements. The statistical confidence of the predictions was tested to determine the number of daily portal measurements needed to give reasonable predictions. Two treatment processes were simulated to examine the potential opportunity for setup margin reduction and dose escalation. The first process mimicked a conventional treatment. A constant margin was assigned to each treatment field to compensate for the average setup error of the patient population. A treatment dose was then prescribed with reference to a fixed normal tissue tolerance, and then fixed in the entire course of treatment. In the second process, the same treatment fields and prescribed dose were used only for the initial plan and treatment. After several initial days of treatments, the treatment field shape and position were assumed to be adaptively modified using a computer-controlled multileaf collimator (MLC) in light of the predicted systematic and random setup errors. The prescribed dose was then escalated until the same normal tissue tolerance, as determined in the first treatment process, was reached.

RESULTS

The systematic setup error and the random setup error were predicted to be within +/-1 mm for the former and +/-0.5 mm for the latter at a > or = 95% confidence level using < or = 9 initial daily portal measurements. In the study, a large number of patients could be treated using a smaller field margin if the adaptive modification process were used. Simulation of the adaptive modification process for prostate treatment demonstrates that additional treatment dose could be safely applied to 64% of patients.

CONCLUSION

The adaptive modification process represents a different approach for use of on-line portal images. The portal imaging information from the initial treatments is used as feedback for reoptimization of the treatment plan, rather than adjustment of the treatment setup. Results from the retrospective study show that the treatment of individual patient can be improved with the adaptive modification process.

VEGF drives cancer-initiating stem cells through VEGFR-2/Stat3 signaling to upregulate Myc and Sox2

Vascular endothelial growth factor-A (VEGF), a potent angiogenic factor, is also implicated in self-renewal in several normal tissue types. VEGF has been shown to drive malignant stem cells but mechanisms thereof and tumor types affected are not fully characterized. Here, we show VEGF promotes breast and lung cancer stem cell (CSC) self-renewal via VEGF receptor-2 (VEGFR-2)/STAT3-mediated upregulation of Myc and Sox2. VEGF increased tumor spheres and aldehyde dehydrogenase activity, both proxies for stem cell function in vitro, in triple-negative breast cancer (TNBC) lines and dissociated primary cancers, and in lung cancer lines. VEGF exposure before injection increased breast cancer-initiating cell abundance in vivo yielding increased orthotopic tumors, and increased metastasis from orthotopic primaries and following tail vein injection without further VEGF treatment. VEGF rapidly stimulated VEGFR-2/JAK2/STAT3 binding and activated STAT3 to bind MYC and SOX2 promoters and induce their expression. VEGFR-2 knockdown or inhibition abrogated VEGF-mediated STAT3 activation, MYC and SOX2 induction and sphere formation. Notably, knockdown of either STAT3, MYC or SOX2 impaired VEGF-upregulation of pSTAT3, MYC and SOX2 expression and sphere formation. Each transcription factor, once upregulated, appears to promote sustained activation of the others, creating a feed-forward loop to drive self-renewal. Thus, in addition to angiogenic effects, VEGF promotes tumor-initiating cell self-renewal through VEGFR-2/STAT3 signaling. Analysis of primary breast and lung cancers (>1300 each) showed high VEGF expression, was prognostic of poor outcome and strongly associated with STAT3 and MYC expression, supporting the link between VEGF and CSC self-renewal. High-VEGF tumors may be most likely to escape anti-angiogenics by upregulating VEGF, driving CSC self-renewal to re-populate post-treatment. Our work highlights the need to better define VEGF-driven cancer subsets and supports further investigation of combined therapeutic blockade of VEGF or VEGFR-2 and JAK2/STAT3.

CD72-deficient mice reveal nonredundant roles of CD72 in B cell development and activation

CD72, a B cell surface protein of the C-type lectin superfamily, recruits the tyrosine phosphatase SHP-1 through its ITIM motif(s). Using CD72-deficient (CD72-/-) mice, we demonstrate that CD72 is a nonredundant regulator of B cell development. In the bone marrow of CD72-/- mice, there was a reduction in the number of mature recirculating B cells and an accumulation of pre-B cells. In the periphery of CD72-/- mice, there were fewer mature B-2 cells and more B-1 cells. In addition, CD72 is a negative regulator of B cell activation, as CD72-/- B cells were hyperproliferative in response to various stimuli and showed enhanced kinetics in their intracellular Ca2+ response following IgM cross-linking.

Comparison of vildagliptin and acarbose monotherapy in patients with Type 2 diabetes: a 24-week, double-blind, randomized trial

AIMS

To compare the efficacy and tolerability of the dipeptidyl peptidase-4 inhibitor, vildagliptin, with the alpha glucosidase inhibitor, acarbose, in drug-naive patients with Type 2 diabetes.

METHODS

This multi-centre, randomized, double-blind, parallel-arm study compared the efficacy and tolerability of vildagliptin (100 mg daily, given as 50 mg twice daily, n = 441) and acarbose (up to 300 mg daily, given as three equally divided doses, n = 220) during 24-week treatment in drug-naive patients with Type 2 diabetes.

RESULTS

Monotherapy with vildagliptin or acarbose decreased glycated haemoglobin (HbA(1c)) (baseline approximately 8.6%) to a similar extent during 24-week treatment. The adjusted mean change from baseline to end-point (AMDelta) in HbA(1c) was -1.4 +/- 0.1% and -1.3 +/- 0.1% in patients receiving vildagliptin and acarbose, respectively, meeting the statistical criterion for non-inferiority (upper limit of 95% confidence interval for between-treatment difference < or = 0.4%). The decrease in fasting plasma glucose was similar with acarbose (-1.5 +/- 0.2 mmol/l) and vildagliptin (-1.2 +/- 0.1 mmol/l). Body weight did not change in vildagliptin-treated patients (-0.4 +/- 0.1 kg) but decreased in acarbose-treated patients (-1.7 +/- 0.2 kg, P < 0.001 vs. vildagliptin). The proportion of patients experiencing any adverse event (AE) was 35% vs. 51% in patients receiving vildagliptin or acarbose, respectively; gastrointestinal AEs were significantly more frequent with acarbose (25.5%) than vildagliptin (12.3%, P < 0.001). No hypoglycaemia was reported for either group.

CONCLUSIONS

Vildagliptin is effective and well tolerated in patients with Type 2 diabetes, demonstrating similar glycaemic reductions to acarbose, but with better tolerability.

Effect on survival of local ablative treatment of metastases from sarcomas: a study of the French sarcoma group

AIMS

Recent data suggest that patients with pulmonary metastases from sarcomas might benefit from ablation of their metastases. Some data are available regarding osteosarcomas/angiosarcomas and lung metastases. The purpose of this study was to assess the efficacy of local ablative treatment on the survival of patients with oligometastases (one to five lesions, any metastatic site, any grade/histology) from sarcomas.

MATERIALS AND METHODS

A multicentric retrospective study of the French Sarcoma Group was conducted in sarcoma patients with oligometastases who were treated between 2000 and 2012. Survival was analysed using multivariate sensitivity analyses with propensity scores to limit bias.

RESULTS

Of the 281 patients evaluated, 164 patients received local treatment for oligometastases between 2000 and 2012. The groups' characteristics were similar in terms of tumour size and remission of the primary tumours. The median follow-up was 25.7 months; 129 (45.9%) patients had died at this point. The median overall survivals were 45.3 (95% confidence interval = 34-73) months for the local treatment group and 12.6 for the other group (95% confidence interval = 9.33-22.9). Survival was better among patients who received local treatment (hazard ratio = 0.47; 95% confidence interval = 0.29-0.78; P < 0.001). Subgroup analyses revealed similar findings in the patients with single oligometastases (hazard ratio = 0.48; 95% confidence interval = 0.28-0.82; P = 0.007); a significant benefit was observed for grade 3, and a trend was observed for grade 2.

CONCLUSION

Local ablative treatment seemed to improve the overall survival of the patients who presented with oligometastatic sarcomas, including soft tissue and bone sarcomas. The survival benefit remained after repeated local treatments for several oligometastatic events. Surgery yielded the most relevant results, but alternative approaches (i.e. radiofrequency ablation and radiotherapy) seemed to be promising. The relevance of these results is strengthened by our analysis, which avoided biases by restricting the population to patients with oligometastatic disease and used propensity scores.

Efficacy and tolerability of vildagliptin as add-on therapy to metformin in Chinese patients with type 2 diabetes mellitus

AIM

To investigate the efficacy and tolerability of vildagliptin as add-on therapy to metformin in Chinese patients with type 2 diabetes mellitus (T2DM) inadequately controlled with metformin.

METHODS

This was a 24-week, randomized, double-blind, placebo-controlled study. Patients with T2DM (N = 438) with haemoglobin A1c (HbA1c) of 7.0-10.0% and fasting plasma glucose (FPG) <15 mmol/l (<270 mg/dl) were randomized (1 : 1 : 1) to vildagliptin 50 mg bid, vildagliptin 50 mg qd or placebo in addition to metformin.

RESULTS

The treatment groups were well balanced at baseline [mean HbA1c, 8.0%, FPG, 8.8 mmol/l (158 mg/dl); body mass index, 25.5 kg/m(2) ]. The adjusted mean change (AMΔ) in HbA1c at endpoint was -1.05 ± 0.08%, -0.92 ± 0.08% and -0.54 ± 0.08% in patients receiving vildagliptin 50 mg bid, 50 mg qd and placebo, respectively. The between-treatment difference (vildagliptin 50 mg bid-placebo) was -0.51 ± 0.11%, p < 0.001. A greater proportion of vildagliptin-treated patients met at least one responder criterion (82.1 and 70.7%) compared to placebo-treated patients (60.4%). The AMΔ at endpoint for FPG with vildagliptin 50 mg bid, -0.95 mmol/l (-17.1 mg/dl); 50 mg qd, -0.84 mmol/l (-15.1 mg/dl) was significantly different compared with the placebo -0.26 mmol/l (-4.68 mg/dl) (p ≤ 0.001). Adverse events (AEs) were reported as 34.2, 36.5 and 37.5% for patients receiving vildagliptin 50 mg bid, 50 mg qd or placebo, respectively. Two patients in the vildagliptin 50 mg qd and one in the placebo group reported serious AEs, which were not considered to be related to the study drug; one incidence of hypoglycaemic event was reported in the vildagliptin 50 mg bid group.

CONCLUSION

Vildagliptin as add-on therapy to metformin improved glycaemic control and was well tolerated in Chinese patients who were inadequately controlled by metformin only.

Nicotine inhibits apoptosis induced by cisplatin in human oral cancer cells

Oral cancer demonstrates a strong epidemiological association with smoking, but little is known about the effect of nicotine on oral cancer cell apoptosis. Nicotine, a major component of cigarette smoke, can regulate cell proliferation and angiogenesis and suppress apoptosis induced by chemotherapeutic drugs. The main aim of this study was to investigate the effects of nicotine on apoptosis induced by cisplatin, which is commonly used to treat advanced oral cancers, in the human oral cancer cell line Tca8113. The cells were stimulated with nicotine in the presence or absence of cisplatin, and apoptosis was assayed. The results showed that nicotine inhibited apoptosis induced by cisplatin. It was also observed that survivin played a role in the inhibitory effect of nicotine on apoptosis. Depletion of survivin reduced the protective effect of nicotine against cisplatin-induced apoptosis. Akt, a physiological survivin kinase, is activated by nicotine. Treatment of Tca8113 cells with the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 blocked nicotine-induced survivin expression and enhanced cell apoptosis. These studies suggest that exposure to nicotine might negatively impact on the apoptotic potential of chemotherapeutic drugs, and that survivin plays a key role in the anti-apoptotic effect of nicotine. The Akt pathway may be required for nicotine function.

Single-center experience of 253 portal vein thrombosis patients undergoing liver transplantation in China

OBJECTIVE

We sought to review the etiopathogenesis, diagnosis, and surgical options for 253 patients with portal vein thrombosis (PVT) undergoing orthotopic liver transplantation (OLT) to assess the the impact of PVT on outcomes.

METHODS

We retrospectively analyzed the data from 2508 adult patients undergoing 2614 OLTs in our center from September 1998 to July 2007. PVT was scored according to the operative findings and Yerdel grading of PVT. No prisoners were used as donors for this study.

RESULTS

Two hundred fifty-three patients were diagnosed with PVT (10.09%): there were 104 grade I; 114, grade II; 29, grade III; and 6, grade IV PVT. Sex and previous splenectomy increased the risk for PVT. In grade I and II cases, we performed simple thrombectomy, eversion thrombectomy, or improved eversion thrombectomy (IET, innovated by our center), producing smooth postoperative recoveries with a 0% in-hospitality mortality. In grade III cases, 18 underwent successful IET. Of 11 subjects who had eversion thrombectomy, six failed, and the distal superior mesentery vein or dilated splanchnic collateral tributary had to be used as the inflow vessel in four patients, and portal vein arterialization were performed in the other two patients, all of whom experienced a smooth postoperative recovery except one who died of hepatic failure and pulmonary infection 2 weeks after the operation. The in-hospitality mortality was 3.45%. In grade IV cases, three underwent successful IET, but another three cases failed, with two of them requiring a renal vein as the inflow vessel, and other one undergoing portocaval hemitransposition, with one postoperative death due to hepatic failure and another of cancer recurrence, an in-hospitality mortality rate of 33.33%. The transfusion requirement among PVT patients was significantly higher than that in non-PVT patients (9.32 +/- 3.12 U vs 6.02 +/- 2.40 U; P < .01). Blood loss in PVT patients who underwent the IET technique was significantly lower than that for an eversion thrombectomy (2800.36 +/- 930.52 mL vs 5700.21 +/- 162.50 mL P < .05). The overall actuarial 1-year survival rate in PVT patients was similar to the controls (86.56% vs 89.40%; P > .05).

CONCLUSION

OLT was successfully performed for PVT patients. The grade of PVT decided the surgical strategy. Similar 1-year survival rates were attained between PVT patients and controls undergoing OLT.

CD72, a negative regulator of B-cell responsiveness

The ability of lymphocytes to respond to antigenic or mitogenic stimulation is regulated not only by specific receptor proteins, but also by both positive and negative regulatory proteins that set or fine-tune the threshold for responsiveness. CD72 is one such regulatory protein on B lymphocytes. It is a member of the C-type lectin superfamily and is expressed on the surface of B cells from the pro-B through the mature B-cell stage. Studies with anti-CD72 antibodies have suggested a positive regulatory role for CD72 in B-cell activation. However, the cytoplasmic tail of CD72 contains two potential immunoreceptor tyrosine-based inhibitory motifs, one of which has been shown to recruit the tyrosine phosphatase SHP- 1. These features suggest a negative regulatory role for CD72. We have generated CD72-deficient mice to elucidate the physiological role of CD72 in B-lymphocyte development and activation. Our analyses of these mice and their B-cell compartment demonstrate that CD72 is a nonredundant regulator of B-cell development and a negative regulator of B-cell responsiveness.

InDels within caprine IGF2BP1 intron 2 and the 3'-untranslated regions are associated with goat growth traits

Insulin-like growth factor 2 mRNA binding protein 1 (IGF2BP1) is involved in the Hedgehog pathway and has been shown to regulate the RNA stability of several growth-related target genes. It is located in a quantitative trait locus showing a strong association with traits related to body size in ducks. Fibroblast growth factor receptor 1 (FGFR1) also participates in Hedgehog signaling pathways and has been reported to be associated with organic growth and development. FGFR1-knockout mice have been shown to have severe postnatal growth defects, including an approximately 50% reduction in body weight and bone mass. Meanwhile, nonsense-mediated mRNA decay factor (SMG6) can maintain genomic stability, which is associated with organic growth and development. Therefore, we hypothesized that IGF2BP1, FGFR1 and SMG6 genes may play important roles in the growth traits of goats. In this study, the existence of two insertion/deletion (InDel) variants within IGF2BP1, one InDel within FGFR1 and two InDels within SMG6 was verified and their correlation with growth traits was analyzed in 2429 female Shaanbei white cashmere goats. Results showed both the 15 bp InDel in intron 2 and the 5 bp InDel in the 3' regulatory region within IGF2BP1 were significantly associated with growth traits (P < 0.05) and goats with the combinatorial homozygous insertion genotypes of these two loci had the highest body weight (P = 0.046). The other InDels within FGFR1 and SMG6 were not obviously associated with growth traits (P > 0.05). Therefore, the two InDels in IGF2BP1 were vital mutations affecting goat growth traits.

Normal free thyroxine in critical nonthyroidal illnesses measured by ultrafiltration of undiluted serum and equilibrium dialysis

Considerable controversy exists concerning the assessment of thyroidal state in critically ill patients with decreased serum T4 and T3 concentrations, in part because serum free T4 values are often low in such patients no matter what method of measurement is used. We developed an ultrafiltration method to measure free T4 and free T3 in undiluted serum and compared the results with those obtained using a standard equilibrium dialysis method to measure free T4 and T3. In 30 consecutive intensive care unit (ICU) patients, serum free T4 values were similar to or higher than those in 12 normal subjects by both methods in most patients and were clearly distinguishable from those in hypothyroid patients. The serum total T4 concentrations in these patients ranged from 12.9-131.3 nmol/L (mean, 68.2; normal mean, 115.8). Free T4 by equilibrium dialysis was highly correlated with free T4 by ultrafiltration in the ICU group (r = 0.91; P less than 0.001). Serum free T3 levels, however, whether measured by equilibrium dialysis or ultrafiltration, were decreased in the ICU patients, confirming other reports of lowered free T3 in critically ill clinically euthyroid patients. Our findings suggest that the use of equilibrium dialysis of undiluted serum or ultrafiltration to measure serum free T4 concentrations will distinguish euthyroid hypothyroxinemic ICU patients from those with hypothyroidism.

Tissue tracking allows rapid and accurate visual evaluation of left ventricular function

AIMS

To evaluate the ability of tissue tracking for rapid assessment of left ventricular function by determination of the systolic mitral annular displacement. Tissue tracking is a new echocardiographic modality based on Doppler Tissue imaging allowing rapid visual assessment of the systolic baso-apical displacement of each myocardial segment in apical views by a graded colour display.

METHODS AND RESULTS

We studied 90 patients (69 male, age 60.4 +/- 10.1 years) with different left ventricular function (25 subjects with normal left ventricular function, 25 patients with homogeneous depression of left ventricular function and 40 patients with prior myocardial infarction). Systolic mitral annular displacement was determined by tissue tracking and M-mode echocardiography. Apical two-, three- and four-chamber views were used to determine the mitral annular displacement of six sites. Left ventricular ejection fraction was determined by two-dimensional echocardiography using Simpson's rule. Tissue tracking was possible in all patients. In the 50 patients with normal left ventricular function or homogeneous depression of left ventricular function, mean mitral annular displacement correlated closely with mitral annular displacement determined by M-mode (r=0.99,P <0.001) and with left ventricular ejection fraction (r=0.97, P<0.001). Left ventricular ejection fraction < or = 30% could be predicted with a sensitivity of 98% and a specificity of 78% using a cut-off value of 4.8mm for the mitral annular displacement determined by tissue tracking. In patients with prior myocardial infarction correlation between the mean mitral annular displacement and left ventricular ejection fraction was lower (r=0.87, P<0.001).

CONCLUSION

Systolic mitral annular displacement determined by tissue tracking correlates closely with mitral annular displacement determined by M-mode and with left ventricular ejection fraction. Thus, tissue tracking allows rapid semiquantitative evaluation of global left ventricular function by assessment of systolic mitral annular displacement.

Changes in telomerase activity and telomere length during human T lymphocyte senescence

It has been proposed that telomeres shorten with every cell cycle because the normal mechanism of DNA replication cannot replicate the end sequences of the lagging DNA strand. Telomerase, a ribonucleoprotein enzyme that synthesizes telomeric DNA repeats at the DNA 3' ends of eukaryotic chromosomes, can compensate for such shortening, by extending the template of the lagging strand. Telomerase activity has been identified in human germline cells and in neoplastic immortal somatic cells, but not in most normal somatic cells, which senesce after a certain number of cell divisions. We and others have found that telomerase activity is present in normal human lymphocytes and is upregulated when the cells are activated. But, unlike the immortal cell lines, presence of telomerase activity is not sufficient to make T cells immortal and telomeres from these cells shorten continuously during in vitro culture. After senescence, telomerase activity, as detected by the TRAP technique, was downregulated. A cytotoxic T lymphocyte (CTL) cell line that was established in the laboratory has very short terminal restriction fragments (TRFs). Telomerase activity in this cell line is induced during activation and this activity is tightly correlated with cell proliferation. The level of telomerase activity in activated peripheral blood T cells, the CTL cell line, and two leukemia cell lines does not correlate with the average TRF length, suggesting that other factors besides telomerase activity are involved in the regulation of telomere length.