Different Levels Of Maturation Research Articles

Trends in Adoption and Maturation of Telehealth Programs at Teaching Hospitals and Health Systems.

Introduction: Although early adopters of telehealth have built and sustained telehealth programs over long periods, little research has been conducted differentiating the characteristics of health systems at different stages of maturation. Methods: This study surveyed 165 major teaching hospitals and health systems from fiscal year 2015 through 2018 about the stage and characteristics of their telehealth services. Respondents reported (i) the progression level of their telehealth program, (ii) which of six services they provide, and (iii) greatest barriers and motivators to implementing telehealth, as well as their overall operational and financial characteristics. Results: Telehealth programs at teaching hospitals progressed steadily and adoption of a wide range of telehealth delivery modes expanded. Hospital operational and financial characteristics corresponding to both higher maturation and the adoption of more delivery modes were identified. Reported barriers and motivations were similar across maturation levels. Discussion: With telehealth's broader use and the heterogeneity of delivery modes being utilized, a binary metric of whether or not to implement telehealth does not sufficiently capture key differences in telehealth programs or differentiate implementation scope and scale across health systems. Conclusions: The findings suggest that programs at different levels of maturation are characteristically different from one another. Identifying factors related to mature telehealth programs may help guide policymakers, future telehealth program leaders, and other stakeholders in identifying barriers to continued investment in telehealth.

Reduction of preg-robbing activity of carbonaceous gold ores with the utilization of surface blinding additives

The carbonaceous matter present in some gold ores adsorbs the gold cyanide complexes from the leached solution and transport them to tailings, resulting in loses and preventing the recovery of the metal – a phenomenon known as preg-robbing. The present work aims at evaluating the capacity of 8blinding additives to deactivate/passivate the carbonaceous matter present in mineral coals and in gold ores. Initially, adsorption experiments with 3 mineral coals at different levels of maturation (anthracite, bituminous and lignite) were carried out to simulate the complex carbonaceous matrix of the gold ores. The coal presenting the best adsorptive capacity was selected for the experiments with the blinding additives. Different concentrations of additives (562–28,125 g/tcoal) and conditioning times (5, 30 and 120 min) were investigated. The blinding additives presenting satisfactory results were used in the deactivation/passivation carbonaceous gold ore experiments. Adsorption experiments showed that the anthracite coal adsorbed gold cyanide while bituminous and lignite coal failed to do so. It is believed that the difference in the adsorptive capacity presented by the mineral coals owes to the structure of the carbonaceous material, and also that the anthracite coal structure is similar to what is found in the carbonaceous gold ores presenting preg-robbing activity. The deactivation/passivation experiments indicated that the additives A1, A2, A3, A4 and A5 suppressed the adsorptive capacity of the anthracite by 60–85% in concentrations varying from 562 to 28,125 g/tcoal respectively. The additive presenting the best performance was A2. Experiments with a carbonaceous gold ore indicated that the use of 350 and 1000 g/tgold ore of additive A1 presented the best recoveries, 90.12 and 90.69%, resulting in the lowest presence of gold contents in the tailings, 1.17 and 1.25 g/t respectively. These values are very close to what was reported for CIL leaching (89.89% and 1.30 g/t) and considerably higher than values observed in the conventional leaching (83.79% and 2.10 g/t). Despite presenting the best deactivation/passivation performance when used with the anthracite coal, additive A2 did not reduce the preg-robbing activity of the carbonaceous matter of the ore, resulting in an increase in gold content in the tailing. The use of additives in the industrial process will demand a simpler and less expensive operational facility and the performance will be similar to the CIL technique.

Histologic and Histomorphometric Analysis of Bone Regeneration with Bovine Grafting Material after 24 Months of Healing. A Case Report.

Anorganic bovine bone mineral matrix (ABBMM) has been reported to have osteoconductive properties and no inflammatory or adverse responses when used as grafting material in sinus augmentation procedures. However, controversy remains in regard to degradation rate of ABBMM. The aim of this study was to histologically and histomorphometrically evaluate the degradation of ABBMM in human bone samples obtained in one patient 24 months after sinus augmentation. Materials and Methods: The histologic and histomorphometric analysis was performed by means of light microscopy in three specimens harvested from the same patient, Results: After 24 months the tissue pattern appeared to be composed of residual particles, some in close contact with the newly formed bone, others separated by translucent areas and osteoid tissues. Newly-formed bone presented different levels of maturation and numerous osteocytes, with greater numbers in bone closer to the grafted particles (27.3% vs. 11.2%, p < 0.05). The histomorphometric analysis showed mean values of 40.84% newly-formed bone, 33.58% residual graft material, 23.84% marrow spaces, and 1.69% osteoid tissue, Conclusions: Even though ABBMM underwent considerable resorption, a great amount of residual grafting material was still present after two years of healing following sinus augmentation. This study confirms that the bovine grafts can be classified as long-term degradation materials.

Pharmacological Rac1 inhibitors with selective apoptotic activity in human acute leukemic cell lines.

Rac1 GTPase has long been recognized as a critical regulatory protein in different cellular and molecular processes involved in cancer progression, including acute myeloid leukemia. Here we show the antitumoral activity of ZINC69391 and 1A-116, two chemically-related Rac1 pharmacological inhibitors, on a panel of four leukemic cell lines representing different levels of maturation. Importantly, we show that the main mechanism involved in the antitumoral effect triggered by the Rac1 inhibitors comprises the induction of the mitochondrial or intrinsic apoptotic pathway. Interestingly, Rac1 inhibition selectively induced apoptosis on patient-derived leukemia cells but not on normal mononuclear cells. These results show the potential therapeutic benefits of targeting Rac1 pathway in hematopoietic malignancies.

Determination of pyrrolizidine alkaloids levels in Symphytum asperum

Onduso SO, Ng‘ang‘a MM, Wanjohi W, Hassanali A. 2017. Determination of pyrrolizidine alkaloids levels in Symphytum asperum. Biofarmasi J Nat Prod Biochem 15: 65-78. The levels of the pyrrolizidine alkaloids (PAs) in the roots and leaves of comfrey (Symphytum asperum Lepech) from two agro-ecological zones in Kenya, Kiambu and Kisii counties during wet (April 2012) and the dry (September 2012) seasons were determined in the present study. The samples were dried beneath the shade for four weeks, continued with ground and extraction of the PAs by applying different solvent systems. The result displayed no significant difference in the percentage of dry weights for the leaves and the roots samples collected from Kisii and Kiambu counties during the wet and dry seasons (p&gt;0.05 at 95 % confidence limit). Gas Chromatography (GC) combined with a Mass spectrometer (MS) was used in the analyses of the samples, characterization, and quantification of major components. Among four PAs identified in the root samples (echimidine (7), 7- acetyllycopsamine (17), 3‘-acetyllycopsamine (18), triangularine (19) and heliosupine (24)), a significant amount of 7- Acetyllycopsamine (17) was evident during the wet season as compared to the dry season (p=0.033, α=0.05, t-test). The other pyrrolizidine alkaloids measured between two seasons did not vary significantly (p&gt;0.05, α=0.05, t-test). All the compounds reported in the root samples are associated with toxicity, and their values exceed the tolerable levels as recommended by relevant regulatory bodies in various countries. One of the most toxic PAs, echimidine (7), was found in all the root samples. The leaf samples, however, showed PAs level below detectable limits using GC-MS. Further study is needed to examine whether PAs is produced from the leaves collected at different levels of maturation and from a broader profile of the plant. Furthermore, it necessary to know the levels of a particular PA and related analogs in a larger profile of the plants cultivated in other agro-ecological zones in Kenya. Study on the toxicity of heliosupine (24) is of future interest, since it is existed in significant amounts, yet such studies have not been done on this constituent. Also, preparative isolation of the PAs should be performed to provide reference standards in other quantification facilities that utilize Gas Chromatography because GC-MS is a rather expensive method.

A functional endosomal pathway is necessary for lysosome biogenesis in Drosophila.

BackgroundLysosomes are the major catabolic compartment within eukaryotic cells, and their biogenesis requires the integration of the biosynthetic and endosomal pathways. Endocytosis and autophagy are the primary inputs of the lysosomal degradation pathway. Endocytosis is specifically needed for the degradation of membrane proteins whereas autophagy is responsible for the degradation of cytoplasmic components. We previously identified the deubiquitinating enzyme UBPY/USP8 as being necessary for lysosomal biogenesis and productive autophagy in Drosophila. Because UBPY/USP8 has been widely described for its function in the endosomal system, we hypothesized that disrupting the endosomal pathway itself may affect the biogenesis of the lysosomes.ResultsIn the present study, we blocked the progression of the endosomal pathway at different levels of maturation of the endosomes by expressing in fat body cells either dsRNAs or dominant negative mutants targeting components of the endosomal machinery: Shibire, Rab4, Rab5, Chmp1 and Rab7. We observed that inhibition of endosomal trafficking at different steps in vivo is systematically associated with defects in lysosome biogenesis, resulting in autophagy flux blockade.ConclusionOur results show that the integrity of the endosomal system is required for lysosome biogenesis and productive autophagy in vivo.Electronic supplementary materialThe online version of this article (doi:10.1186/s12860-016-0115-7) contains supplementary material, which is available to authorized users.

Commentary: “Comparison of spike parameters from optically identified GABAergic and glutamatergic neurons in sparse cortical cultures”

GENERAL COMMENTARY article Front. Cell. Neurosci., 22 April 2015Sec. Cellular Neurophysiology https://doi.org/10.3389/fncel.2015.00157

Characterization of Neutrophil Subsets in Healthy Human Pregnancies

We have previously shown that in successful pregnancies increased arginase activity is a mechanism that contributes to the suppression of the maternal immune system. We identified the main type of arginase-expressing cells as a population of activated low-density granulocytes (LDGs) in peripheral blood mononuclear cells and in term placentae. In the present study, we analyzed the phenotype of LDGs and compared it to the phenotype of normal density granulocytes (NDGs) in maternal peripheral blood, placental biopsies and cord blood. Our data reveal that only LDGs but no NDGs could be detected in placental biopsies. Phenotypically, NDGs and LDGs from both maternal and cord blood expressed different levels of maturation, activation and degranulation markers. NDGs from the maternal and cord blood were phenotypically similar, while maternal, cord and placental LDGs showed different expression levels of CD66b. LDGs present in cord blood expressed higher levels of arginase compared to maternal and placental LDGs. In summary, our results show that in maternal and cord blood, two phenotypically different populations of neutrophils can be identified, whereas in term placentae, only activated neutrophils are present.

A Novel Cellular Autoaggregative Developmentally CRP Regulated Behaviour Generates Massively Chondrule-Like Formations over Surface of Old &amp;lt;i&amp;gt;Escherichia coli&amp;lt;/i&amp;gt; K-12 Macrocolony Biofilms

How Escherichia coli bacteria develop a particular colonial, 3-D biofilm morphological pattern is still a poorly understood process. Recently, we reported a new E. coli K-12 morphotype exhibited by old macrocolonies described as volcano-like. The formative developmental process of this morphotype has been presented as a suitable experimental model for the study of 3D patterning in macrocolony biofilms. Here, we report the optical microscopy observations and genetic analysis that have unveiled the existence of a novel autoaggregative behaviour which generates massive lumpiness over the surface of the volcano-like macrocolonies. These lumpy formations are generated by the autoaggregation and strong interaction of tightly packed bacterial cells in structures with a chondrule-like appearance which give the colony’s surface its characteristic microscopic lumpy phenotype. Furthermore, they exhibit different levels of maturation from the edge to the center of the colony. Hence, its generation appears to follow a spatiotemporal program of development during the macrocolony’s morphogenesis. Interestingly, the agar’s hardness influences the morphology exhibited by these formations, with high agar concentration (1.5%, 15 g/L) suppressing its development. This new auto-aggregative E. coli’s behaviour does not require the activity of the biofilm master regulator CsgD, the adhesiveness of flagella, pili type 1, adhesin Ag43, β-1,6-N-acetyl-D-glucosamine polymer-PGA, cellulose or colanic acid, but it is under glucose repression and the control of cAMP receptor protein (CRP). The possible physiological role of these chondrule-like formations in the adaptability of the colony to different stressful environmental conditions is discussed.

Efficient cellular fractionation improves RNA sequencing analysis of mature and nascent transcripts from human tissues

BackgroundThe starting material for RNA sequencing (RNA-seq) studies is usually total RNA or polyA+ RNA. Both forms of RNA represent heterogeneous pools of RNA molecules at different levels of maturation and processing. Such heterogeneity, in addition to the biases associated with polyA+ purification steps, may influence the analysis, sensitivity and the interpretation of RNA-seq data. We hypothesize that subcellular fractions of RNA may provide a more accurate picture of gene expression.ResultsWe present results for sequencing of cytoplasmic and nuclear RNA after cellular fractionation of tissue samples. In comparison with conventional polyA+ RNA, the cytoplasmic RNA contains a significantly higher fraction of exonic sequence, providing increased sensitivity in expression analysis and splice junction detection, and in improved de novo assembly of RNA-seq data. Conversely, the nuclear fraction shows an enrichment of unprocessed RNA compared with total RNA-seq, making it suitable for analysis of nascent transcripts and RNA processing dynamics.ConclusionOur results show that cellular fractionation is a more rapid and cost effective approach than conventional polyA+ enrichment when studying mature RNAs. Thus, RNA-seq of separated cytosolic and nuclear RNA can significantly improve the analysis of complex transcriptomes from mammalian tissues.

PKHhigh cells within clonal human nephrospheres provide a purified adult renal stem cell population

The existence and identification of adult renal stem cells is a controversial issue. In this study, renal stem cells were identified from cultures of clonal human nephrospheres. The cultured nephrospheres exhibited the activation of stem cell pathways and contained cells at different levels of maturation. In each nephrosphere the presence of 1.12–1.25 cells mirroring stem cell properties was calculated. The nephrosphere cells were able to generate three-dimensional tubular structures in 3D cultures and in vivo. In clonal human nephrospheres a PKHhigh phenotype was isolated using PKH26 epifluorescence, which can identify quiescent cells within the nephrospheres. The PKHhigh cells, capable of self-renewal and of generating a differentiated epithelial, endothelial and podocytic progeny, can also survive in vivo maintaining the undifferentiated status. The PKHhigh status, together with a CD133+/CD24− phenotype, identified a homogeneous cell population displaying in vitro self-renewal and multipotency capacity. The resident adult renal stem cell population isolated from nephrospheres can be used for the study of mechanisms that regulate self-renewal and differentiation in adult renal tissue as well as in renal pathological conditions.

Potential immunoregulatory role of heme oxygenase-1 in human milk: a combined biochemical and molecular modeling approach

Human milk contains biological factors that are involved in a newborn's growth and immune system regulation. By integrating standard biochemical experimental protocols with computational methods, the present study investigates the presence of heme oxygenase-1 (HO-1), a cytoprotective enzyme, in human milk at different levels of maturation and in milk formulae. Furthermore, we evaluated cytokine and glutathione S-transferase (GSH) levels. Samples were collected from colostrum (on Day 1 after birth), from transition milk (on Postdelivery Days 7 and 14) and from mature milk (on Day 30 after delivery) in 14 healthy women. HO-1 protein, GSH and cytokines levels were measured using enzyme-linked immunosorbent assay and flow cytometry. HO-1 protein levels were significantly higher in colostrum (1.33 ng/ml; 5th centile 0.92; 95th centile 2.38) and in transition milk at 14 days (0.97 ng/ml; 5th centile 0.87; 95th centile 1.45) than in mature milk (0.9 ng/ml; 5th centile 0.8; 95th centile 1.38). Levels of HO-1 in milk formulae were similar to those in colostrum. No significant differences in GSH content were observed in mature milk, transition milk and colostrum, whereas significantly higher GSH levels were observed in milk formulae. No significant levels of cytokines, with the exception of interleukin-8, were found. Computational studies on the possible interactions between HO-1 and CD91 were carried out by a battery of softwares, namely, GRAMM (version 1.03), DALI, CLUSTALW (version 2.0), PatchDock and FireDock, mutually counterchecking and validating each other. The computational results, the strong convergence (to the same “solution”) of which finally leads to an “experimental-like” character, showed that HO-1 may bind to CD91, thus suggesting its major role as a new chaperokine in immune response regulation. These findings, which connect and integrate biochemical data and computational data interpretation, represent a synergistic and powerful means of conducting biological research.

Characterization of Maturity Level in Laying Hen Manure by Chemical and Thermogravimetric Analysis

This study aims at investigating maturity levels in manure from laying hens in order to encourage its agronomic re-utilization. In fact the use of unstable/insufficiently mature manure could potentially damage both soils and crops. Effective, easy to reproduce methods are needed in order to assess bio-stabilisation and maturity levels, particularly for biomass that has not undergone conventional composting. This study compares samples of caged laying hen manure, an organic matter rich in nutrients, N and P and devoid of litter or bulking agents, at different levels of maturation. Both chemical (dry matter, ashes, carbon and its fractioning, total and ammoniacal nitrogen) and physical methods, such as thermogravimetry, were used to characterize them. Such physical methods do introduce any sample modification and shorten the analysis time. From a statistical point of view, chemical methods are effective only in distinguishing among different drying methods connected with manure management systems. Only thermogravimetric analysis can identify mature samples by means of total mass loss in the range RT- 900°C, mass loss in the range 350-425°C and energy release at 500°C. In addition, thermogravimetric profiles could be used to define a fingerprint for this kind of biomass.

CD45 expression in low-grade B-cell non-Hodgkin's lymphomas

CD45 is a glycoprotein expressed in all lymphohemopoietic cells. Its expression increases during B-lymphocyte ontogeny. Few data are available about CD45 expression in the various types of low-grade B-cell non-Hodgkin's lymphomas (NHL). Low levels of CD45 have been reported in pathologic lymphocytes from typical chronic lymphocytic leukemia (CLL) and higher levels of this antigen have been observed in some cases of atypical CLL and in some cases of other types of NHL. One hundred and seven bone marrow samples of NHL with bone marrow infiltration were investigated: 45 typical CLL, 15 atypical CLL, 9 mantle cell lymphomas (MCL), 1 MCL with CD23 expression, 18 marginal zone lymphomas (MZL), 6 lymphoplasmacytic lymphomas (LPL), 6 follicular lymphomas (FL), and 7 hairy cell leukemias (HCL). CD45 expression was evaluated by flow cytometry: pathologic lymphocytes were identified on the basis of specific immunophenotypic profile, CD19/K or CD19/λ co-expression. Results were expressed as median fluorescence intensity (MFI) along a 1024 linear scale. CD45 expression was measured also on autologous T-lymphocytes and a “CD45 index” was calculated as the ratio MFI of pathologic B-lymphocytes/MFI of T-lymphocytes, to normalize the results obtained. We found four CD45 expression patterns: very low in typical CLL; relatively low in MCL; intermediate intensity in MZL, LPL, and FL; very high expression in HCL. Among the atypical cases, very high CD45 expression was found in one case of CD23-negative CLL, in CD23-positive MCL, and CLL with atypical morphology. The results indicate different levels of maturation in low-grade NHL and may help to characterize such neoplasias.

Comparison of the Somatic and Psychosexual Maturation in Menarcheal and Nonmenarcheal Girls

This study reports on the relation between somatic and psychosexual development in 911 urban girls age 8 to 17 years. Subjects were examined by anthropometric and questionnaire methods. We compared the variability of somatic proportions and indexes in two groups of girls at the same age, but with different levels of maturation (menarcheal vs nonmenarcheal). We also assessed their attitudes and knowledge in spheres of sexuality, partners, and matrimonial relationships. We observed that menarcheal girls differed significantly for several anthropometrical values (body weight, sitting height, gluteal circumference, arm circumference) for some age groups, and we recorded significant differences in values of some indexes (Quetelet-Bouchard, Pignet-Vervaek, BMI). The psychosexual development of the girls was assessed by the questionnaire method. The girls were asked to explain various terms. The main aim of our questionnaire was to detect the existence of a relationship between somatic and psychosexual development, whether knowledge of menarcheal girls is more advanced than knowledge of nonmenarcheal girls. Our results show that although there is a significant somatic distinction between menarcheal and nonmenarcheal girls, we are not able to unambiguously state that menarcheal girls are more psychosexually developed.

Expression Profile of Osteoblast Lineage at Defined Stages of Differentiation

The inherent heterogeneity of bone cells complicates the interpretation of microarray studies designed to identify genes highly associated with osteoblast differentiation. To overcome this problem, we have utilized Col1a1 promoter-green fluorescent protein transgenic mouse lines to isolate bone cells at distinct stages of osteoprogenitor maturation. Comparison of gene expression patterns from unsorted or isolated sorted bone cell populations at days 7 and 17 of calvarial cultures revealed an increased specificity regarding which genes are selectively expressed in a subset of bone cell types during differentiation. Furthermore, distinctly different patterns of gene expression associated with major signaling pathways (Igf1, Bmp, and Wnt) were observed at different levels of maturation. Some of our data differ from current models of osteoprogenitor cell differentiation and emphasize components of the pathways that were not revealed in studies based on a total cell population. Thus, applying methods to generate more homogeneous populations of cells at a defined level of cellular differentiation from a primary osteogenic culture is feasible and leads to a novel interpretation of the gene expression associated with increasing levels of osteoprogenitor maturation.

Levels of S100B protein are higher in mature human milk than in colostrum and milk-formulae milks

Background & Aims: Human milk is believed to contain biological factors involved in the regulation of newborn growth, including brain development. Recently, it has also been shown to contain the calcium-binding S100B protein, regarded as a neurotrophic factor. The present study investigates the concentrations of this protein in colostrum, human milk at different levels of maturation and in milk-formulae. Methods: Samples for S100B measurements were collected from human colostrum (on day 1 after birth), from transition milk (on post-delivery days 7 and 14) and from mature milk (on day 30 after delivery) in 14 healthy women and from 14 milk-formulae. The S100B protein levels were measured using a commercially available specific immunoluminometric assay. Results: Mean S100B protein levels were significantly higher in mature human milk (117.9±36.7 μg/l) than in transition milk at 14 days (106.7±38.1 μg/l) and at 7 days (92.7±37.8 μg/l), colostrum (74.6±37.6 μg/l) or milk-formulae (24.8±19.5 μg/l) ( P<0.001, for all). A correlation between human milk S100B levels and the gestational age at which samples were obtained was also found ( r=0.39; P<0.01). Conclusions: These findings, possibly related to S100B's neurotrophic role, offers useful information to the investigation of the role of S100B protein in brain maturation.

Quantitative and functional expression of somatostatin receptor subtypes in human thymocytes.

We recently demonstrated the expression of somatostatin (SS) and SS receptor (SSR) subtype 1 (sst1), sst2A, and sst3 in normal human thymic tissue and of sst1 and sst2A on isolated thymic epithelial cells (TEC). We also found an inhibitory effect of SS and octreotide on TEC proliferation. In the present study, we further investigated the presence and function of SSR in freshly purified human thymocytes at various stages of development. Thymocytes represent a heterogeneous population of lymphoid cells displaying different levels of maturation and characterized by specific cell surface markers. In this study, we first demonstrated specific high-affinity 125I-Tyr(11)-labeled SS-14 binding on thymocyte membrane homogenates. Subsequently, by RT-PCR, sst2A and sst3 mRNA expression was detected in the whole thymocyte population. After separation of thymocytes into subpopulations, we found by quantitative RT-PCR that sst2A and sst3 are differentially expressed in intermediate/mature and immature thymocytes. The expression of sst3 mRNA was higher in the intermediate/mature CD3+ fraction compared with the immature CD2+CD3- one, whereas sst2A mRNA was less abundant in the intermediate/mature CD3+ thymocytes. In 7-day-cultured thymocytes, SSR subtype mRNA expression was lost. SS-14 significantly inhibited [3H]thymidine incorporation in all thymocyte cultures, indicating the presence of functional receptors. Conversely, octreotide significantly inhibited [3H]thymidine incorporation only in the cultures of immature CD2+CD3- thymocytes. Subtype sst3 is expressed mainly on the intermediate/mature thymocyte fraction, and most of these cells generally die by apoptosis. Because SS-14, but not octreotide, induced a significant increase in the percentage of apoptotic thymocytes, it might be that sst3 is involved in this process. Moreover, sst3 has recently been demonstrated on peripheral human T lymphocytes, which derive directly from mature thymocytes, and SS analogs may induce apoptosis in these cells. Interestingly, CD14+ thymic cells, which are cells belonging to the monocyte-macrophage lineage, selectively expressed sst2A mRNA. Finally, SSR expression in human thymocytes seems to follow a developmental pathway. The heterogeneous expression of SSR within the human thymus on specific cell subsets and the endogenous production of SS as well as SS-like peptides emphasize their role in the bidirectional interactions between the main cell components of the thymus involved in intrathymic T cell maturation.

Quantification of Thrombopoietic Activity in Bone Marrow Aspirates of Dogs

The aims of the study were to investigate possible influences of different numbers of counted fields on slides, and different slides on the counting of platelet precursors, and to establish guidelines for bone marrow examination in dogs. The study was based on bone marrow slides of 131 healthy dogs. The slides were prepared by a squash technique. On each slide the number of thrombopoietic cells at different levels of maturation were counted in all fragment-containing fields.The results of a variance component model revealed no influence of different slides, in contrast to a high variance related to different fields. Between 20 and 25 low power fields (100× magnification) had to be examined to achieve an imprecision of 20%. An imprecision of 10% required the counting of 100 fields. The lowest thrombopoietic activity was seen in the bone marrow of dogs aged one to six years. The total number of platelet percursors per field was significantly higher in adult female (10.4±2.67) than in male dogs (7.84±2.04, P=0.0008) as was the number of megakaryocytes. We recommend assessment of thrombopoiesis on the basis of 20–25 fragment-containing low power fields and that age- and sex-related differences should be considered.

Presence of a functional vitamin D receptor does not correlate with vitamin D3 phenotypic effects in myeloid differentiation

Although VDR is expressed in all the acute myeloid leukemia cell populations studied, most of these leukemias do not exhibit any phenotypic response when exposed to VD. To determine whether VD resistance is related to an altered VDR function, we performed an analysis of VDR expression, phosphorylation, DNA binding capacity and transactivation activity in several leukemic myeloid cell lines arrested at different levels of maturation. Our results indicate that VD induces a clear phenotypic effect, i.e. terminal monocytic differentiation, only in leukemic cells of M2/M3 (intermediate myeloblasts) and M5 (monoblasts) types but not in erythroid precursor cells, early leukemic myeloblasts (M0/M1 type) and promyelocytes (M3 type). VDR expression and function are evident in all the nuclear extracts obtained from the different myeloid cell lines after 12 h of VD treatment, but VD activation of monocytic differentiation is limited to a narrow differentiation window characterized by the M2 type myeloid cellular context.