Development of membrane-potential responsiveness by myeloid leukemia cells during neutrophilic differentiation

The ability of a myeloid leukemia cell line (HL-60) to undergo membrane electrical potential changes was followed during neutrophilic differentiation induced by 2 compounds. Membrane-potential changes were induced with 12-O-tetradecanoylphorbol 13-acetate (TPA) or formyl-methionyl-leucyl-phenylalanine (FMLP) and were monitored by flow cytometry. The magnitude of the membrane-potential response to TPA increased in a more uniform manner as the population of cells matured than did acquisition of mature morphology or ability to undergo the respiratory burst in response to TPA. The response to TPA and FMLP of HL-60 cells, maximally induced to differentiate by dimethylsulfoxide, closely resembled that of neutrophils. Thus, HL-60 cells may be a useful tool in the study of the relation between membrane depolarization and subsequent cellular activation.     

Ultrastructural studies of endocrine-like cells in the fundic gastric mucosa of the bullfrog,Rana catesbeiana

Summary This study is concerned with electron-microscopic observations on endocrine or paracrine cells in the fundic gastric mucosa of the bullfrog. Also, an attempt was made to identify the histamine-releasing cells involved in the secretagogue response. At least three distinct endocrine-like cell types were found. The classification is based on the appearance of secretory granules and other organelles, and the relationship of endocrine-like cells with other cells in the tissue. The amphibian endocrine-like cells resemble the ECL, D and EC cells of mammals. Type-I (ECL) cells showed degranulation after repeated stimulation with tetragastrin (TG), acetylcholine (ACh) and K⁺ depolarizing solution, all of which release histamine.     

Release of Catecholamines from Superfused Bovine Adrenal Chromaffin Cells Cultured on Microcarrier Beads

A procedure is described for the establishment of stable primary cultures of bovine chromaffin cells on microcarrier beads. The cells flatten and send out processes with varicosities over a few days and maintain their catecholamine content for 2 weeks. The beads may be incorporated into a superfusion apparatus with a chamber volume of about 150 microliters, enabling the efficient perfusion of a high density of cells. The response to the introduction of nicotine and high potassium into the perfusing medium is shown to be more rapid and more transient than hitherto described, with each secretagogue producing a different degree of preferential stimulation of noradrenaline-secreting cells.     

NOD1 modulates decidual stromal cell function to maintain pregnancy in the early trimester

We sought to explore the functions and modulated factors of NOD1 in normal decidual stromal cells (DSCs) derived from the first trimester pregnancy and whether existed different expression of NOD1 between normal and unexplained recurrent pregnancy loss (URPL) in DSCs. Twenty‐six patients with normal pregnancies that required abortion and 12 URPL patients at first trimester were enrolled for the study. As a result, we found lower levels of NOD1 in the DSCs derived from URPL compared with those from normal early trimester pregnancy. Furthermore, increased NOD1 expression in the normal DSCs induced apoptosis and increased monocyte chemotactic protein‐1 (MCP‐1) and IL‐1β (interleukin 1 beta) secretion but decreased their invasion capacity. In addition, several cytokines such as IL‐1β, tumour necrosis factor‐alpha (TNF‐α), interferon‐gamma (IFN‐γ), and interleukin‐17 (IL‐17) were present at the maternal‐fetal interface in RPL and were found to regulate NOD1 expression in primary DSCs. Our study indicates that RPL may be associated with NOD1 aberrant expression in DSCs, which plays a significant role in maintaining pregnancy via infection control and regulation of immune responses that might affect the pregnancy outcome. We expect that our results will bring more comprehensively understanding about the connection between NOD1 and RPL for researchers.     

Immunological detection of a cysteine protease in the skin and other tissues

Summary Monospecific antibody directed to cysteine protease of 2-day-old rat epidermis recently characterized as being different from the proteases previously reported was produced in rabbits. By immunofluorescence microscopy and immunoperoxidase staining with an avidin-biotin-peroxidase method the protease was found to be present in the epidermis of rodents of different ages as well as that of humans, but not in the dermis. The staining in germinative cells was more intense than in cells in the superficial layers. It appeared as irregular patches in the nuclei and stained more diffusely in the cytoplasm where small granular components, strongly stained, were identified. The staining patterns in granular cells showed accumulation of the antigen in a granular form. The morphology and distribution of granules resembled those of keratohyalin-like granules in the nucleus and dense homogenous deposits in the cytoplasm. In cornified cells the reaction product was localized by the plasma membrane where concentration of the dense homogenous deposits occurred, suggesting that the cysteine protease is one component of the unique and characteristic structure of differentiated keratinocytes. In addition, the cysteine protease antigen having the same molecular weight as the epidermal enzyme was detected in liver, kidney and lung indicating a wider tissue distribution of the protease. The significance of the protease in regulation of cellular functions remains to be investigated.     

Bioengineering Considerations for a Nurturing Way to Enhance Scalable Expansion of Human Pluripotent Stem Cells

Understanding how defects in mechanotransduction affect cell‐to‐cell variability will add to the fundamental knowledge of human pluripotent stem cell (hPSC) culture, and may suggest new approaches for achieving a robust, reproducible, and scalable process that result in consistent product quality and yields. Here, the current state of the understanding of the fundamental mechanisms that govern the growth kinetics of hPSCs between static and dynamic cultures is reviewed, the factors causing fluctuations are identified, and culture strategies that might eliminate or minimize the occurrence of cell‐to‐cell variability arising from these fluctuations are discussed. The existing challenges in the development of hPSC expansion methods for enabling the transition from process development to large‐scale production are addressed, a mandatory step for industrial and clinical applications of hPSCs.     

Localization and characterization of T-cell subpopulations and natural killer cells (HNK 1+ cells) in the human tonsilla palatina

Summary In the present study attention was focussed on several lymphoid subpopulations and specific stationary cells of the human tonsilla palatina. They were labeled at the light- and electron-microscopic levels by means of monoclonal antibodies to cell surface antigens. Cells resembling interdigitating cells (IDC-like cells) within the crypt epithelium and the interdigitating cells in the parafollicular T-cell region express the HLA-DR antigen. This fact suggests a relationship between these two populations of cells. Both cell types were frequently found in close contact to T-helper cells labeled with Anti-Leu 3a. This fact is discussed as a confirmation of earlier suggestions that the tonsillar crypt epithelium serves as T-cell region. Cytotoxic/ suppressor-T cells (OKT 8 ⁺) and Leu 7-positive cells do not appear to contact interdigitating cells. Anti-Leu 7 is a monoclonal antibody, that defines a differentiation antigen shown to be selectively expressed on human natural killer cells (NK-cells). With the use of the immuno-electron-microscopic labeling method it was possible to analyze the ultrastructure of this lymphoid subpopulation. Two morphologically distinguishable subtypes of Leu 7-positive cells populate different microenvironments: The Leu 7-positive large-granular lymphocyte was predominantly found in the crypt epithelium, while numerous Leu 7-positive cells located in the germinal centers had the appearance of small lymphocytes. This finding is discussed in favour of distinct phenotypes representing different stages in a differentiation pathway of the maturing NK-cell: Small Leu 7-positive lymphocytes in the germinal centers are supposed to be functionally inactive precursors, and only the Leu 7-positive large granulated lymphocytes in the crypt epithelium may represent differentiated active NK-cells. This interpretation is in agreement with the observation that the tonsilla palatina, in spite of containing numerous Leu 7-positive cells, shows only low NK-activity against tumor cells.Glossary of Abbreviations used in this Paper DAB diamino-benzidine - DMSO dimethyl sulfoxide - HLA human leucocyte antigen - HLA-DR human leucocyte antigen, D-region related - Ia-antigen immune-associated antigen of the MHC - IDC interdigitating cell - IDC-like cell cell that resembles an interdigitating cell - LGL large granular lymphocyte - MHC major histocompatibility gene complex - NK-cell natural killer cell - PBS phosphate-buffered saline