Human thrombopoietin levels are high when thrombocytopenia is due to megakaryocyte deficiency and low when due to increased platelet destruction

Thrombopoietin (TPO), the ligand for c-mpl, stimulates proliferation of committed megakaryocytic progenitors and induces maturation of megakaryocytes. To better understand factors regulating TPO levels, we measured blood levels of TPO in patients with impaired platelet production due to aplastic anemia (AA) and with platelet destructive disorders, including idiopathic thrombocytopenic purpura (ITP), posttransfusion purpura (PTP), drug purpura (DP), and X-linked thrombocytopenia (XLTP). The TPO receptor capture enzyme immunoassay (EIA) used had a detection limit of integral of approximately-150 to 200 pg/mL. TPO was undetectable in 88 of 89 normal individuals. Eighteen of 19 patients with AA and a mean platelet count (MPC) of 18,000/microliters (2,000 to 61,000/microliters) had markedly elevated TPO levels (mean, 1,467 pg/mL; range, 597 to 3,834 pg/mL). Eight AA patients who responded to immunosuppressive therapy with their MPC increasing to 140,000/microliters (92,000 to 175,000/microliters) had substantial decreases in TPO (mean, 440 pg/mL; range, 193 to 771 pg/mL). Initial TPO levels did not differ significantly between responders and nonresponders. In contrast, all 21 patients with ITP and an MPC of 16,000/microliters (1,000 to 51,000 /microliters) had undetectable TPO levels, as did 6 patients with acute PTP or DP and 2 patients with XLTP. Megakaryocyte mass, reflected in the rate of platelet production, appears to be the major determinant of TPO levels in thrombocytopenic patients rather than circulating platelet levels per se. Measurement of serum TPO may be useful in differentiating thrombocytopenias due to peripheral destruction from those due to thrombopoietic failure.     

REPAIR OF ABDOMINAL AORTIC ANEURYSM AFTER RENAL TRANSPLANTATION WITHOUT RENAL PROTECTION

SUMMARY The successful resection is reported of an abdominal aortic aneurysm after renal transplantation without the use of bypass or cooling procedure to preserve the kidney.     

JunB as a potential mediator of PTHrP actions: new gene targets Ephrin B1 and VCAM‐1

Parathyroid hormone‐related protein (PTHrP) is an integral mediator of physiologic and pathologic processes and has demonstrated actions in the periodontium. PTHrP functions via AP‐1, and specifically through JunB. This study identified JunB‐dependent downstream mediators of PTHrP using OCCM cementoblastic transfectants with JunB over‐ or reduced expression. Over‐expressing cells showed an increase in proliferation, while the opposite was seen in siRNA transfected cells. Microarray analysis of over‐expressing cells revealed more than 1000 regulated genes. Three genes were investigated in more detail. The PTH/PTHrP receptor (PTHR1) and ephrin B1 (EfnB1) were down‐regulated, and vascular cell adhesion molecule‐1 (VCAM‐1) was up‐regulated with JunB over‐expression. JunB siRNA transfectants had increased PTHR1, but reduced ephrin B1 and unaltered VCAM‐1 in vitro. To validate these targets, parental OCCM cells and primary osteoblasts were treated with PTHrP, resulting in reduced PTHR1 and ephrin B1, and increased VCAM‐1. Cell transfectants were implanted subcutaneously in vivo, and microarray analysis and RT‐PCR performed. Over‐expression of JunB down‐regulated PTHR1 and ephrin B1, and increased VCAM‐1. JunB siRNA transfectant implants had increased PTHR1 and ephrin B1, but no altered VCAM‐1. These data highlight new gene targets for PTHrP and indicate JunB is a critical mediator of PTHrP actions.     

Screening for vancomycin‐resistant enterococci: results of a survey in Stockholm

Fang H, Nord CE, Ullberg M. Screening for vancomycin‐resistant enterococci: results of a survey in Stockholm. APMIS 2010; 118: 413–7. Vancomycin‐resistant enterococci (VRE) are emerging in Stockholm hospitals. To rapidly screen for VRE from stool and rectal swab samples, a detection assay combining broth enrichment and real‐time PCR was set up. From September to December 2008, 6914 samples were screened for VRE using the broth‐PCR combined assay. Of them, 5463 samples were reported as negative the day after sampling. Among the 6914 samples, 47 was screened as vanA probable and 44 of them were confirmed as VRE; 1314 samples was screened as vanB probable and 93 of them were confirmed as VRE. The 44 vanA‐type VRE isolates, detected from 31 patients, were clustered into four genetic types by pulsed‐field gel electrophoresis (PFGE). The same PFGE type was observed in multiple isolates recovered from the same patient with vanA VRE. The 93 vanB‐type VRE isolates were detected from 60 patients, 59 of them harboring VRE with PFGE type 1. One patient with vanB VRE had two isolates of distinct PFGE types (types 1 and 5). PFGE type 1 and PFGE type 2 were predominant clones in vanB and vanA strains, respectively, represented by 98.3% (59/60) of patients with vanB VRE and 77.4% (24/31) of patients with vanA VRE.     

Autologous melanocyte–keratinocyte suspension in the treatment of vitiligo

Background In stable vitiligo, several techniques of autologous transplantation of melanocytes are used. Autologous melanocyte transplantation of non‐cultured melanocytes is one of those techniques with variable reported outcomes. Objective The objective of this study was to evaluate the response to autologous melanocyte–keratinocytes suspension transplantation in cases of stable vitiligo. Methods A total of 25 cases of vitiligo were treated by autologous melanocyte–keratinocytes suspension transplantation. After 6–17 months, patients’ response was evaluated according to the extent of pigmentation (excellent 90–100%, good 50–89%, fair 20–49% and poor response <20%). Results Of the 25 patients treated, 22 continued the follow‐up period. Five (23%) patients showed excellent response, 7 (32%) good, 6 (27%) fair and 4(18%) showed poor response. Conclusion Unlike transplantation of cultured melanocytes, which requires experience in culture technique, autologous melanocyte–keratinocytes suspension transplantation is an easy economic technique, which may be used in resistant areas of stable vitiligo.