Dendritic cell ontogeny: A human dendritic cell lineage of myeloid origin

Dendritic cells (DC) have been thought to represent a family of closely related cells with similar functions and developmental pathways. The best-characterized precursors are the epidermal Langerhans cells, which migrate to lymphoid organs and become activated DC in response to inflammatory stimuli. Here, we demonstrate that a large subset of DC in the T cell-dependent areas of human lymphoid organs are nonactivated cells and belong to a separate lineage that can be identified by high levels of the interleukin 3 receptor α chain (IL-3Rαhi). The CD34+IL-3Rαhi DC progenitors are of myeloid origin and are distinct from those that give rise to Langerhans cells in vitro. The IL-3Rαhi DC furthermore appear to migrate to lymphoid organs independently of inflammatory stimuli or foreign antigens. Thus, DC are heterogeneous with regard to function and ontogeny.

A role for intracellular pH in membrane IgM-mediated cell death of human B lymphomas

We show that anti-IgM-induced cell death in a human B lymphoma cell line, B104, is associated with early intracellular acidification and cell shrinkage. In contrast, another human B cell lymphoma line, Daudi, less susceptible to B cell antigen receptor-mediated cell death, responded to anti-IgM with an early increase in intracellular pH (pHi). The anti-IgM-induced changes of pHi were associated with different levels of activation of the Na+/H+ exchanger isoform 1 (NHE1) as judged by its phosphorylation status. Prevention of anti-IgM-induced cell death in B104 cells by the calcineurin phosphatase inhibitor, cyclosporin A, abrogated both intracellular acidification and cell shrinkage and was associated with an increase in the phosphorylation level of NHE1 within the first 60 min of stimulation. This indicates a key role for calcineurin in regulating pHi and cell viability. The potential role of pHi in cell viability was confirmed in Daudi cells treated with an Na+/H+ exchanger inhibitor 5-(N,N-hexamethylene)amiloride. These observations indicate that the outcome of the anti-IgM treatment depends on NHE1-controlled pHi. We suggest that inactivation of the NHE1 in anti-IgM-stimulated cells results in intracellular acidification and subsequently triggers or amplifies cell death.

Building a retrospective collection in pharmacy: a brief history of the literature with some considerations for U.S. health sciences library professionals

This paper argues that historical works in pharmacy are important tools for the clinician as well as the historian. With this as its operative premise, delineating the tripartite aspects of pharmacy as a business enterprise, a science, and a profession provides a conceptual framework for primary and secondary resource collecting. A brief history and guide to those materials most essential to a historical collection in pharmacy follows. Issues such as availability and cost are discussed and summarized in checklist form. In addition, a glossary of important terms is provided as well as a list of all the major U.S. dispensatories and their various editions. This paper is intended to serve as a resource for those interested in collecting historical materials in pharmacy and pharmaco-therapeutics as well as provide a history that gives context to these classics in the field. This should provide a rationale for selective retrospective collection development in pharmacy.

Guanylyl cyclase C agonists regulate progression through the cell cycle of human colon carcinoma cells

The effects of Escherichia coli heat-stable enterotoxin (ST) and uroguanylin were examined on the proliferation of T84 and Caco2 human colon carcinoma cells that express guanylyl cyclase C (GC-C) and SW480 human colon carcinoma cells that do not express this receptor. ST or uroguanylin inhibited proliferation of T84 and Caco2 cells, but not SW480 cells, in a concentration-dependent fashion, assessed by quantifying cell number, cell protein, and [3H]thymidine incorporation into DNA. These agonists did not inhibit proliferation by induction of apoptosis, assessed by TUNEL (terminal deoxynucleotidyl transferase-mediated dNTP-biotin nick end labeling of DNA fragments) assay and DNA laddering, or necrosis, assessed by trypan blue exclusion and lactate dehydrogenase release. Rather, ST prolonged the cell cycle, assessed by flow cytometry and [3H]thymidine incorporation into DNA. The cytostatic effects of GC-C agonists were associated with accumulation of intracellular cGMP, mimicked by the cell-permeant analog 8-Br-cGMP, and reproduced and potentiated by the cGMP-specific phosphodiesterase inhibitor zaprinast but not the inactive ST analog TJU 1-103. Thus, GC-C agonists regulate the proliferation of intestinal cells through cGMP-dependent mechanisms by delaying progression of the cell cycle. These data suggest that endogenous agonists of GC-C, such as uroguanylin, may play a role in regulating the balance between epithelial proliferation and differentiation in normal intestinal physiology. Therefore, GC-C ligands may be novel therapeutic agents for the treatment of patients with colorectal cancer.

Islet amyloid formation associated with hyperglycemia in transgenic mice with pancreatic beta cell expression of human islet amyloid polypeptide.

Pancreatic islet amyloid deposits are a characteristic pathologic feature of non-insulin-dependent diabetes mellitus and contain islet amyloid polypeptide (IAPP; amylin). We used transgenic mice that express human IAPP in pancreatic beta cells to explore the potential role of islet amyloid in the pathogenesis of non-insulin-dependent diabetes mellitus. Extensive amyloid deposits were observed in the pancreatic islets of approximately 80% of male transgenic mice > 13 months of age. Islet amyloid deposits were rarely observed in female transgenic mice (11%) and were never seen in nontransgenic animals. Ultrastructural analysis revealed that these deposits were composed of human IAPP-immunoreactive fibrils that accumulated between beta cells and islet capillaries. Strikingly, approximately half of the mice with islet amyloid deposits were hyperglycemic (plasma glucose > 11 mM). In younger (6- to 9-month-old) male transgenic mice, islet amyloid deposits were less commonly observed but were always associated with severe hyperglycemia (plasma glucose > 22 mM). These data indicate that expression of human IAPP in beta cells predisposes male mice to the development of islet amyloid and hyperglycemia. The frequent concordance of islet amyloid with hyperglycemia in these mice suggests an interdependence of these two conditions and supports the hypothesis that islet amyloid may play a role in the development of hyperglycemia.

A rural virtual health sciences library project: research findings with implications for next generation library services*

Purpose: The Shared Hospital Electronic Library of Southern Indiana (SHELSI) research project was designed to determine whether access to a virtual health sciences library and training in its use would support medical decision making in rural southern Indiana and achieve the same level of impact seen by targeted information services provided by health sciences librarians in urban hospitals.

Health sciences libraries in Kuwait: a study of their resources, facilities, and services

The purpose of this study was to examine the current status of health sciences libraries in Kuwait in terms of their staff, collections, facilities, use of information technology, information services, and cooperation. Seventeen libraries participated in the study. Results show that the majority of health sciences libraries were established during the 1980s. Their collections are relatively small. The majority of their staff is nonprofessional. The majority of libraries provide only basic information services. Cooperation among libraries is limited. Survey results also indicate that a significant number of health sciences libraries are not automated. Some recommendations for the improvement of existing resources, facilities, and services are made.

Providing health information to the general public: a survey of current practices in academic health sciences libraries*

A questionnaire was mailed to 148 publicly and privately supported academic health sciences libraries affiliated with Association of American Medical Colleges (AAMC)–accredited medical schools in the United States and Canada to determine level of access and services provided to the general public. For purposes of this study, “general public” was defined as nonaffiliated students or health care professionals, attorneys and other nonhealth-related professionals, patients from affiliated or other hospitals or clinics, and general consumers. One hundred five (71%) libraries responded. Results showed 98% of publicly supported libraries and 88% of privately supported libraries provided access to some or all of the general public. Publicly supported libraries saw greater numbers of public patrons, often provided more services, and were more likely to circulate materials from their collections than were privately supported libraries. A significant number of academic health sciences libraries housed a collection of consumer-oriented materials and many provided some level of document delivery service, usually for a fee. Most allowed the public to use some or all library computers. Results of this study indicated that academic health sciences libraries played a significant role in serving the information-seeking public and suggested a need to develop written policies or guidelines covering the services that will be provided to minimize the impact of this service on primary clientele.

Monograph use at an academic health sciences library: the first three years of shelf life

Objective: To study the circulation of monographs during the first three years of shelf life at an academic health sciences library.

Cell stress-regulated human major histocompatibility complex class I gene expressed in gastrointestinal epithelium.

Conventional major histocompatibility complex (MHC) class I genes encode molecules that present intracellular peptide antigens to T cells. They are ubiquitously expressed and regulated by interferon gamma. Two highly divergent human MHC class I genes, MICA and MICB, are regulated by promoter heat shock elements similar to those of HSP70 genes. MICA encodes a cell surface glycoprotein, which is not associated with beta 2-microglobulin, is conformationally stable independent of conventional class I peptide ligands, and almost exclusively expressed in gastrointestinal epithelium. Thus, this MHC class I molecule may function as an indicator of cell stress and may be recognized by a subset of gut mucosal T cells in an unusual interaction.

Effects of TH1 and TH2 cytokines on CD8+ cell response against human immunodeficiency virus: implications for long-term survival.

CD8+ cells from long-term survivors [LTS; infected with human immunodeficiency virus (HIV) for 10 or more years and having CD4+ cell counts of > or = 500 cells per microliters] have a 3-fold greater ability to suppress HIV replication than do CD8+ cells from patients who have progressed to disease (progressors) during the same time period. A change in the pattern of cytokines produced in the host from those that typically favor cell-mediated immunity (T helper 1, TH1 or type 1) to those that down-regulate it (T helper 2, TH2 or type 2) was investigated as a cause of this reduced CD8+ cell anti-HIV function. Treatment of CD8+ cells from LTS with the TH1 cytokine interleukin (IL)-2 enhanced their anti-HIV activity, whereas exposure of these cells to TH2 cytokines IL-4 or IL-10 reduced their ability to suppress HIV replication and to produce IL-2. IL-2 could prevent and reverse the inhibitory effects of IL-4 and IL-10. Moreover, prolonged exposure of CD8+ cells from some progressors to IL-2 improved the ability of these cells to suppress HIV replication. These observations support previous findings suggesting that strong CD8+ cell responses play an important role in maintaining an asymptomatic state in HIV infection. The data suggest that the loss of CD8+ cell suppression of HIV replication associated with disease progression results from a shift in cytokine production within the infected host from a TH1 to a TH2 pattern. Modulation of these cytokines could provide benefit to HIV-infected individuals by improving their CD8+ cell anti-HIV activity.

Intraembryonic hematopoietic cell migration during vertebrate development.

Vertebrate hematopoietic stem cells are derived from vental mesoderm, which is postulated to migrate to both extra- and intraembryonic positions during gastrula and neurula stages. Extraembryonic migration has previously been documented, but the origin and migration of intraembryonic hematopoietic cells have not been visualized. The zebrafish and most other teleosts do not form yolk sac blood islands during early embryogenesis, but instead hematopoiesis occurs solely in a dorsal location known as the intermediate cell mass (IM) or Oellacher. In this report, we have isolated cDNAs encoding zebrafish homologs of the hematopoietic transcription factors GATA-1 and GATA-2 and have used these markers to determine that the IM is formed from mesodermal cells in a posterior-lateral position on the yolk syncytial layer of the gastrula yolk sac. Surprisingly, cells of the IM then migrate anteriorly through most of the body length prior to the onset of active circulation and exit onto the yolk sac. These findings support a hypothesis in which the hematopoietic program of vertebrates is established by variations in homologous migration pathways of extra- and intraembryonic progenitors.

Immortalization of distinct human mammary epithelial cell types by human papilloma virus 16 E6 or E7.

Multiple mammary epithelial cell (MEC) types are observed both in mammary ducts in vivo and in primary cultures in vitro; however, the oncogenic potential of different cell types remains unknown. Here, we used human papilloma virus 16 E6 and E7 oncogenes, which target p53 and Rb tumor suppressor proteins, respectively, to immortalize MECs present in early or late passages of human mammary tissue-derived cultures or in milk. One MEC subtype was exclusively immortalized by E6; such cells predominated in late-passage cultures but were rare at early passages and apparently absent in milk. Surprisingly, a second cell type, present only in early-passage tissue-derived cultures, was fully immortalized by E7 alone. A third cell type, observed in tissue-derived cultures and in milk, showed a substantial extension of life span with E7 but eventually senesced. Finally, both E6 and E7 were required to fully immortalize milk-derived MECs and a large proportion of MECs in early-passage tissue-derived cultures, suggesting the presence of another discrete subpopulation. Identification of MECs with distinct susceptibilities to p53- and Rb-targeting human papillomavirus oncogenes raises the possibility that these cells may serve as precursors for different forms of breast cancer.

Rapid selection of cell subpopulation-specific human monoclonal antibodies from a synthetic phage antibody library.

Peripheral blood leukocytes incubated with a semisynthetic phage antibody library and fluorochrome-labeled CD3 and CD20 antibodies were used to isolate human single-chain Fv antibodies specific for subsets of blood leukocytes by flow cytometry. Isolated phage antibodies showed exclusive binding to the subpopulation used for selection or displayed additional binding to a restricted population of other cells in the mixture. At least two phage antibodies appeared to display hitherto-unknown staining patterns of B-lineage cells. This approach provides a subtractive procedure to rapidly obtain human antibodies against known and novel surface antigens in their native configuration, expressed on phenotypically defined subpopulations of cells. This approach does not depend on immunization procedures or the necessity to repeatedly construct phage antibody libraries.