Human burst-forming units-erythroid need direct interaction with stem cell factor for further development

To understand the factors that regulate the early growth and development of immature erythroid progenitor cells, the burst-forming units-erythroid (BFU-E), it is necessary to have both highly purified target cells and a medium free of serum. When highly purified human blood BFU-E were cultured in a serum-free medium adequate for the growth of later erythroid progenitors, BFU-E would not grow even with the addition of recombinant human interleukin-3 (rIL-3), known to be essential for these cells. However, the addition of recombinant human stem cell factor (rSCF), which supports germ cell and pluripotential stem cell growth, stimulated BFU-E to grow equally well in serum-free as in serum-containing medium. Limiting dilution studies showed that rSCF acts directly on the BFU-E that do not require accessory cells for growth. Furthermore, rSCF was necessary for BFU-E development during the initial 7 days of culture, until these cells reached the stage of the late progenitors, the colony-forming units-erythroid (CFU-E). These studies indicate that early erythropoiesis is dependent on the direct action of SCF that not only affects early stem cells but is continually necessary for the further development of committed erythroid progenitor cells until the CFU-E stage of maturation.     

The effect of influenza vaccination on IL2 production in healthy elderly: implications for current vaccination practices.

Age-related senescence of T-cell mediated responses is well recognized. This study was designed to determine how aging affects the T-cell mediated Interleukin 2 (IL2) response to influenza vaccination. A group of healthy elderly individuals were compared to a control group of healthy young adults for their response to the 1990 influenza vaccine. Cultures of peripheral blood mononuclear cells (PBMC) were prepared from venous blood samples taken prevaccination (pre) and 8 and 12 weeks post-vaccination (post). PBMC cultures stimulated with inactivated A/Shanghai/16/89 (contained in the 1990 vaccine) and A/Philippine/2/82 (not contained in the vaccine) were assayed for peak IL2 activity. We find that after influenza vaccination, there was an insignificant increase in IL2 activity when PBMC from the young control group were stimulated with A/Shanghai/16/89 (pre, 5.14 U/mL/10(6) PBMC; post, 6.64 U/mL/10(6) PBMC) but there was a significant increase in IL2 activity when stimulated with A/Phillippine/2/82 (pre, 1.5 U/mL/10(6) PBMC; post, 8.3 U/mL/10(6) PBMC). In similar cultures of PBMC from the elderly group, there was a significant increase in IL2 response to both A/Shanghai/16/89 (pre, 1.6 U/mL/10(6) PBMC; post, 3.5 U/mL/10(6) PBMC) and A/Philippine/2/82 (pre, 0.86 U/mL/10(6) PBMC; post, 8.3 U/mL/10(6) PBMC). Measurements of CD4+/CD8+ populations were not affected by vaccination and were not significantly different in the two groups. Subgroup analysis of the elderly group revealed that previous influenza vaccination in 1989 did not significantly affect IL2 levels measured in the present study. This study shows that in healthy elderly, influenza vaccination effectively restores IL2 activity to normal. There appears to be an age-related decrease in the duration of T-cell memory.(ABSTRACT TRUNCATED AT 250 WORDS)     

Zinc Status Alters Alzheimer's Disease Progression through NLRP3-Dependent Inflammation

Alzheimer''s disease is a devastating neurodegenerative disease with a dramatically increasing prevalence and no disease-modifying treatment. Inflammatory lifestyle factors increase the risk of developing Alzheimer''s disease. Zinc deficiency is the most prevalent malnutrition in the world and may be a risk factor for Alzheimer''s disease potentially through enhanced inflammation, although evidence for this is limited. Here we provide epidemiological evidence suggesting that zinc supplementation was associated with reduced risk and slower cognitive decline, in people with Alzheimer''s disease and mild cognitive impairment. Using the APP/PS1 mouse model of Alzheimer''s disease fed a control (35 mg/kg zinc) or diet deficient in zinc (3 mg/kg zinc), we determined that zinc deficiency accelerated Alzheimer''s-like memory deficits without modifying amyloid β plaque burden in the brains of male mice. The NLRP3-inflammasome complex is one of the most important regulators of inflammation, and we show here that zinc deficiency in immune cells, including microglia, potentiated NLRP3 responses to inflammatory stimuli in vitro, including amyloid oligomers, while zinc supplementation inhibited NLRP3 activation. APP/PS1 mice deficient in NLRP3 were protected against the accelerated cognitive decline with zinc deficiency. Collectively, this research suggests that zinc status is linked to inflammatory reactivity and may be modified in people to reduce the risk and slow the progression of Alzheimer''s disease.SIGNIFICANCE STATEMENT Alzheimer''s disease is a common condition mostly affecting the elderly. Zinc deficiency is also a global problem, especially in the elderly and also in people with Alzheimer''s disease. Zinc deficiency contributes to many clinical disorders, including immune dysfunction. Inflammation is known to contribute to the risk and progression of Alzheimer''s disease; thus, we hypothesized that zinc status would affect Alzheimer''s disease progression. Here we show that zinc supplementation reduced the prevalence and symptomatic decline in people with Alzheimer''s disease. In an animal model of Alzheimer''s disease, zinc deficiency worsened cognitive decline because of an enhancement in NLRP3-driven inflammation. Overall, our data suggest that zinc status affects Alzheimer''s disease progression, and that zinc supplementation could slow the rate of cognitive decline.     

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.     

Reanalysis of Antisera Specificities and Binding Characteristics of Rat Pituitary Hormone Assays

Rat pituitary hormone radioimmunoassays (RIAs) are widely used in reproductive research, yet data on specificity and binding characteristics of many of the antisera are not widely available. This report characterizes one set of rat antisera supplied by the National Institutes of Health (USA). Rat follicle-stimulating hormone (FSH) and thyrotropin-stimulating hormone (TSH) antisera appear specific, but TSH exhibited significant competition in the rat luteinizing hormone (LH) assay. In addition, statistically significant nonparallelism was demonstrable in all three assay systems. This creates further problems in characterizing antisera cross-reactivity and may make potency estimates for pituitary standards inaccurate.     

Aspects of training in clinical medical sciences in dentistry (human disease): recent graduates' perspectives from a UK dental school

Teaching the management of medical emergencies is an important part of most courses in Clinical Medical Sciences in Dentistry (Human Disease). The aim of this study was to examine which medical emergencies graduates from the School of Dental Sciences at Newcastle University had experienced 1 year after qualification and their perceptions of their ability to assess a patient's fitness for treatment or to manage a medical emergency. The study instrument was a computer readable questionnaire. Very few emergencies had been experienced in general practice at this stage of their career, but all respondents either strongly agreed or agreed that their training had adequately equipped them to assess a patient's medical history and deal with medical emergencies. There were, however, aspects of the course that upon reflection that clearly needed to be addressed, including the use of different teachers for aspects of the medical emergency teaching.     

Needle puncture injury causes acute and long‐term mechanical deficiency in a mouse model of intervertebral disc degeneration

Low back pain is a significant socioeconomic burden and intervertebral disc degeneration has been implicated as a cause. A reliable animal model of disc degeneration is necessary to evaluate therapeutics, and functional metrics are essential to quantify their benefit. To this end, needle puncture injuries were created in the caudal intervertebral discs of mice to induce disc degeneration. Compression, torsion, and creep mechanics were assessed both immediately and after eight weeks to distinguish between the effects of injury and the subsequent reparative or degenerative response. Two needle sizes (29 and 26 gauge) were used to determine injury size‐dependence. Compressive stiffness (62%), torsional stiffness (60%), and early damping stiffness (84%) decreased immediately after injury with the large needle (26G). These mechanical properties did not change over time despite structural and compositional changes. At 8 weeks following large needle injury, disc height decreased (37%), nucleus pulposus (NP) glycosaminoglycan content decreased (41%), and NP collagen content increased (45%). The small needle size had no significant effect on mechanics and did not initiate degenerative changes in structure and composition. Thus, the injection of therapeutics into the NP with a minimal needle size may limit damage due to the needle insertion. These findings, along with the wide commercial availability of mouse‐specific biological probes, indicate that the mouse caudal disc model can be a powerful tool for investigating disc degeneration and therapy. © 2013 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 31:1276–1282, 2013