Interleukin-6 and its receptor are expressed by human megakaryocytes: in vitro effects on proliferation and endoreplication

Interleukin-6 (IL-6) is a pleiotropic cytokine that plays an important role in the megakaryocytic differentiation. Recently, we have observed that IL-6 is synthesized by several human cell lines with megakaryocytic features. In this study, we have investigated whether a similar phenomenon occurs during normal megakaryocytic differentiation. Human megakaryocytes (MK) were obtained by culturing normal marrow in liquid culture with aplastic plasma (AP). First, an IL-6 secretion in bone marrow culture enriched in MK as well as in purified MK populations was demonstrated by a biologic assay. Second, IL-6 mRNA was detected in a purified population of MK by the polymerase chain reaction and dot blot analysis. IL-6 mRNA and protein were undetectable in platelets. Third, in situ hybridization procedure demonstrated the presence of IL-6 mRNA in individual immature MK. Fourth, IL-6 protein was detected in MK at the unicellular level by an immunoalkaline phosphatase technique using a monoclonal antibody against IL-6. Furthermore, the presence of IL-6 receptor (IL-6-R) on MK was demonstrated by in situ hybridization using an IL-6-R probe and in situ autoradiography after binding with [125I]-labeled recombinant IL-6. The IL-6 endogenously produced in liquid cultures containing normal human plasma or AP was subsequently neutralized. This resulted in a 50% decrease of the MK growth with a minor shift in the ploidy distribution toward lower values. In semisolid cultures the addition of anti-IL-6 antibodies led to a 42% decrease in colony number in cultures stimulated by IL-3 but not in other conditions of culture. These results suggest that normal human megakaryocytopoiesis might be regulated in part by an IL-6 autocrine loop.     

YM022, a highly potent and selective CCKB antagonist inhibiting gastric acid secretion in the rat, the cat and isolated rabbit glands

Summary— We investigated the effects of the novel CCK_B/gastrin antagonist YM022 on gastric acid secretion in vivo and in vitro, compared to CI-988 and L365.260 as reference antagonists. In the anaesthetized rat, pentagastrin-induced stimulation of gastric acid secretion was dose-dependently and up to 100% inhibited by iv administration of YM022 with an ID₅₀ of 0.009 ± 0.0006 μmol/kg h in comparison to 0.6 ± 0.03 and 3.40 ± 0.05 μmol/kg h for CI-988 and L-365,260, respectively. In the gastric fistula cat, iv administration of YM022 produced a similar inhibitory effect with an ID₅₀ of 0.02 μmol/kg in comparison to 1.6 and 2.5 μmol/kg for CI-988 and L-365,260, respectively. Furthermore, bolus injection of 0.6 μmol/kg YM022 produced 100% inhibition within 30 min and 85% inhibition was still observed after 3 h. In the isolated rabbit gastric glands, CCK₈-stimulated ¹⁴C-aminopyrine uptake was inhibited according to the following rank order of potency: YM022 (IC₅₀ = 0.0012 μM) ≫ CI-988 (IC₅₀ = 0.2 μM) ≫ L365.260 (IC₅₀ = 2.8 μM). Unlike with L365.260, no influence of CI-988 and YM022 on histamine-stimulated acid output was shown in this study. Thus, YM022 is a highly potent and selective gastric CCK₈/gastrin receptor antagonist and has a long-lasting inhibitory effect on gastric acid secretion.     

The molecular basis of the Kidd blood group polymorphism and its lack of association with type 1 diabetes susceptibility

The Kidd blood group locus encodes a urea transporter which is expressed on human red cells and in the kidney. This gene is located on chromosome 18q12, and evidence for linkage and association with type 1 diabetes mellitus has been reported. To investigate this further, the genetic basis for the blood group Jk(a)/Jk(b) polymorphism was first determined by sequencing reverse-transcribed reticulocyte RNAs from Jk(a+b-) and Jk(a-b+) donors. The Jk(a)/Jk(b) polymorphism was caused by a transition (G838A), resulting in a Asp280Asn amino acid substitution and an MnlI restriction fragment length polymorphism (RFLP). Using the MnlI RFLP, we found that the Jk(a)/Jk(b) polymorphism was not in linkage disequilibrium with type 1 diabetes in 228 multiplex UK and US families tested.      

Test isocinétique précoce après ligamentoplastie antérieure de genou : résultats et conclusions

Objectives

To compare 4-months isokinetic results after anterior cruciate ligament reconstruction with patellar tendon or hamstring tendons.

Material and methods

A retrospective study during 5 years concerning isokinetic records from patients who went to our rehabilitation center after anterior cruciate ligament reconstruction, and who did an isokinetic test 4 months after surgery. There was 146 patients, 116 males and 30 females, 69 with hamstring reconstruction and 77 with patellar tendon reconstruction.

Results

In Kenneth-Jones surgery, there is more deficience on leg extensors, while hamstrings are more deficient after hamstrings reconstruction surgery. This deficience concerns peak torque and work, whatever speed.

Conclusion

Leg flexion deficience in hamstring reconstruction surgery is due to late work during reeducation, because of pain and injuries localized on sample area. There is also loose of biomechanical properties due to muscular fibrosis. For the two reconstruction surgeries, leg extension deficience is due to pain and edema.     

The challenges and pitfalls of incorporating evidence from cardiovascular outcomes trials in health economic modelling of type 2 diabetes

The clinical evidence base for evaluating modern type 2 diabetes interventions has expanded greatly in recent years, with numerous efficacious treatment options available (including dipeptidyl peptidase-4 inhibitors, glucagon-like peptide-1 receptor agonists and sodium-glucose cotransporter-2 inhibitors). The cardiovascular safety of these interventions has been assessed individually versus placebo in numerous cardiovascular outcomes trials (CVOTs), statistically powered to detect differences in a composite endpoint of major adverse cardiovascular events. There have been growing calls to incorporate these data in the long-term modelling of type 2 diabetes interventions because current diabetes models were developed prior to the conduct of the CVOTs and therefore rely on risk equations developed in the absence of these data. However, there are numerous challenges and pitfalls to avoid when using data from CVOTs. The primary concerns are around the heterogeneity of the trials, which have different study durations, inclusion criteria, rescue medication protocols and endpoint definitions; this results in significant uncertainty when comparing two or more interventions evaluated in separate CVOTs, as robust adjustment for these differences is difficult. Analyses using CVOT data inappropriately can dilute clear evidence from head-to-head clinical trials, and blur healthcare decision making. Calibration of existing models may represent an approach to incorporating CVOT data into diabetes modelling, but this can only offer a valid comparison of one intervention versus placebo based on a single CVOT. Ideally, model development should utilize patient-level data from CVOTs to prepare novel risk equations that can better model modern therapies for type 2 diabetes.