Thrombopoietin stimulates megakaryocytopoiesis, myelopoiesis, and expansion of CD34+ progenitor cells from single CD34+Thy-1+Lin- primitive progenitor cells

Thrombopoietin (TPO) or MpI ligand is known to stimulate megakaryocyte (MK) proliferation and differentiation. To identify the earliest human hematopoietic cells on which TPO acts, we cultured single CD34+Thy- 1+Lin- adult bone marrow cells in the presence of TPO alone, with TPO and interleukin-3 (IL-3), or with TPO and c-kit ligand (KL) in the presence of a murine stromal cell line (Sys1). Two distinct growth morphologies were observed: expansion of up to 200 blast cells with subsequent differentiation to large refractile CD41b+ MKs within 3 weeks or expansion to 200-10,000 blast cells, up to 25% of which expressed CD34. The latter blast cell expansions occurred over a 3- to 6-week period without obvious MK differentiation. Morphological staining, analysis of surface marker expression, and colony formation analysis revealed that these populations consisted predominantly of cells committed to the myelomonocytic lineage. The addition of IL-3 to TPO-containing cultures increased the extent of proliferation of single cells, whereas addition of KL increased the percentage of CD34+ cells among the expanding cell populations. Production of multiple colony- forming unit-MK from single CD34+Thy-1+Lin- cells in the presence of TPO was also demonstrated. In limiting dilution assays of CD34+Lin- cells, TPO was found to increase the size and frequency of cobblestone areas at 4 weeks in stromal cultures in the presence of leukemia inhibitory factor and IL-6. In stroma-free cultures, TPO activated a quiescent CD34+Lin-Rhodamine 123lo subset of primitive hematopoietic progenitor cells into cycle, without loss of CD34 expression. These data demonstrate that TPO acts directly on and supports division of cells more primitive than those committed to the MK lineage.     

A Study of Perceived Racial Discrimination in Black Men Who Have Sex with Men (MSM) and Its Association with Healthcare Utilization and HIV Testing

In HPTN 061, a study of Black men who have sex with men (MSM), we evaluated the association of healthcare-specific racial discrimination with healthcare utilization and HIV testing among 1167 HIV-negative participants. Median age was 38 years, 41 % were uninsured, and 38 % had an annual household income <$10,000. Overall, 19 % reported healthcare-specific racial discrimination directed toward family, friend, or self; 61 % saw a healthcare provider in the previous 6 months and 81 % HIV tested within the past year. Healthcare-specific racial discrimination was positively associated with seeing a provider [adjusted odds ratio (AOR) = 1.4 (1.0, 2.0)] and HIV testing [AOR = 1.6 (1.1, 2.4)] suggesting that barriers other than racial discrimination may be driving health disparities related to access to medical care and HIV testing among Black MSM. These results contrast with previous studies, possibly due to measurement or cohort differences, strategies to overcome discrimination, or because of greater exposure to healthcare.     

Outcomes after cardiac arrest in an adult burn center

Objective

Adult burn patients who experience in-hospital cardiac arrest (CA) and undergo cardiopulmonary resuscitation (CPR) represent a unique patient population. We believe that they tend to be younger and have the added burden of the burn injury compared to other populations. Our objective was to determine the incidence, causes and outcomes following cardiac arrest (CA) and cardio-pulmonary resuscitation (CPR) within this population.

Methods

We conducted a retrospective review at the US Army Institute of Surgical Research (ISR) burn intensive care unit (BICU). Charts from 1st January 2000 through 31st August 2009 were reviewed for study. Data were collected all on adult burn patients who experienced in-hospital CA and CPR either in the BICU or associated burn operating room. Patients undergoing CPR elsewhere in our burn unit were excluded because we could not validate the time of CA since they are not routinely monitored with real-time rhythm strips. The study population included civilian burn patients from the local catchment area and burn casualties from the conflicts in Iraq and Afghanistan, but patients with do-not-resuscitate (DNR) orders were excluded.

Results

We found 57 burn patients who had in-hospital CA and CPR yielding an incidence of one or more in-hospital CA of 34 per 1000 admissions (0.34%). Fourteen of these patients (25%) survived to discharge while 43 (75%) died. The most common initial cardiac rhythm was pulseless electrical activity (50.9%). The most common etiology of CA among burn patients was respiratory failure (49.1%). The most significant variable affecting survival to discharge was duration of CPR (P < 0.01) with no patient surviving more than 7 min of CPR.

Conclusions

CPR in burn patients is sometimes effective, and those patients who survive are likely to have good neurological outcomes. However, prolonged CPR times are unlikely to result in return of spontaneous circulation and may be considered futile. Further, those who experience multiple CA are unlikely to survive to discharge.     

Charlson Co‐morbidity Index and albumin significantly associated with fracture risk in peritoneal dialysis patients

Published literature on fracture in dialysis patients seldom addressed the effect of co‐morbidity and malnutrition. In this study, we reported the incidence and risk factors for fracture in peritoneal dialysis patients. Peritoneal dialysis patients who had fractures between 2006 and 2011 were recruited. Demographic data, details of fracture, Charlson Co‐morbidity Index (CCI) and biochemical parameters were also collected. Non‐fracture controls, matched for age, gender and duration of dialysis, were also recruited at ratio 1:1 for fracture risk analysis. The incidence of fracture was 1 in 37 patient‐years. The commonest site of fracture was neck of femur (n = 16, 55.2%). Twenty‐four patients (82.8%) developed fracture after slip and fall injury. Eight out of 17 self‐ambulatory patients (47.1%) became non‐ambulatory after fracture. Infection was the commonest complication during hospitalization. Univariant analysis demonstrated high CCI (P = 0.001), hypoalbuminaemia (P < 0.001), loss of self autonomy (P = 0.006) and non‐ambulatory state (P = 0.011) significantly associated with increased fracture risk. However, only CCI (odds ratio (OR) 1.373, P = 0.028) and albumin (OR 0.893, P = 0.025) increased fracture risk significantly on multivariant analysis. Bone profile and parathyroid hormone were not significant risk factors. To conclude, fracture associated with adverse outcome in peritoneal dialysis patients. High CCI score and hypoalbuminaemia significantly increase risk of fracture.     

ESHRE PGD Consortium data collection VI: cycles from January to December 2003 with pregnancy follow-up to October 2004

The sixth report of the ESHRE PGD Consortium is presented, relating to cycles collected for the calendar year 2003 and follow-up of the pregnancies and babies born up to October 2004. Since the beginning of the data collections, there has been a steady rise in the number of cycles, pregnancies and babies reported. For this report, 50 centres participated, reporting on 2984 cycles, 501 pregnancies and 373 babies born. Five hundred and twenty-nine cycles were reported for chromosomal abnormalities, 516 cycles were reported for monogenic diseases, 137 cycles were reported for sexing for X-linked diseases, 1722 cycles were reported for preimplantation genetic screening (PGS) and 80 cycles were reported for social sexing. Data VI is compared to the cumulative data for data collections I-V.     

Comparative study of Kaposi's sarcoma-associated herpesvirus serological assays using clinically and serologically defined reference standards and latent class analysis

Accurate determination of infection with Kaposi's sarcoma-associated herpesvirus (KSHV) has been hindered by the lack of a "gold standard" for comparison of serological assays used to estimate KSHV prevalence in serosurveys conducted in different settings. We have evaluated the performance of five in-house (developed at University College London [UCL], United Kingdom, and at the virology laboratory of the Instituto de Medicine Tropical [IMT] in Sao Paulo, Brazil) and two commercial (ABI and DIAVIR) serological assays to detect antibodies to latency-associated nuclear antigen (LANA) and to lytic KSHV antigens. We used a variety of serum samples assembled to represent populations likely to be at high, intermediate, and low risk of KSHV infection in Brazil. Composite reference standard panels were prepared based on clinical and serological parameters, against which assay performances were assessed using conventional Bayesian statistics and latent class analysis (LCA). Against the clinical reference standard, in-house immunofluorescence assays to detect anti-LANA antibodies (IFA-LANA) produced at UCL and IMT had similar performances, with sensitivities of 61% (95% confidence interval [CI], 48% to 74%) and 72% (95% CI, 58% to 83%) and specificities of 99% (95% CI, 94% to 100%) and 100% (95% CI, 96% to 100%), respectively, and only the IMT IFA-LANA was included in LCA, together with the IMT IFA-lytic and four enzyme-linked immunosorbent assays (ELISAs). The LCA indicated that the IMT whole-virus ELISA performed best (sensitivity, 87% [95% CI, 81% to 91%]; and specificity, 100% [95% CI, 98% to 100%]), confirming the results obtained with the conventional statistical approach. Commercially available ELISA-based tests yielded the lowest specificities using a spectrum of serum samples. The evaluation of KSHV serological assays is warranted before planning serosurveys in various settings.