SARS-CoV-2 air and surface contamination in residential settings

SARS-CoV-2 transmission occurs mainly indoors, through virus-laden airborne particles. Although the presence and infectivity of SARS-CoV-2 in aerosol are now acknowledged, the underlying circumstances for its occurrence are still under investigation. The contamination of domiciliary environments during the isolation of SARS-CoV-2-infected patients in their respective rooms in individual houses and in a nursing home was investigated by collecting surface and air samples in these environments. Surface contamination was detected in different contexts, both on high and low-touch surfaces. To determine the presence of virus particles in the air, two sampling methodologies were used: air and deposition sampling. Positive deposition samples were found in sampling locations above the patient's height, and SARS-CoV-2 RNA was detected in impactation air samples within a size fraction below 2.5 μm. Surface samples rendered the highest positivity rate and persistence for a longer period. The presence of aerosolized SARS-CoV-2 RNA occurred mainly in deposition samples and closer to symptom onset. To evaluate the infectivity of selected positive samples, SARS-CoV-2 viability assays were performed, but our study was not able to validate the virus viability. The presented results confirm the presence of aerosolized SARS-CoV-2 RNA in indoor compartments occupied by COVID-19 patients with mild symptoms, in the absence of aerosol-generating clinical procedures.

Prevention of Initial Depressive Disorders Among at-Risk Portuguese Adolescents

This study evaluated whether Arnarson and Craighead's (2009, 2011) developmentally based behavioral and cognitive program that prevented the initial episode of depressive disorders among Icelandic adolescents could be adapted to prevent depressive disorders among "at-risk" Portuguese adolescents. One hundred sixty-eight Portuguese mid-adolescents (primarily 14 to 15 years old), who had subsyndromal symptoms of depression but who had never met criteria for a depressive disorder, were identified by classroom screening with the CDI and subsequent K-SADS-PL interview. All 168 adolescents were offered participation in the 14-week prevention program; 70 agreed to participate in the program, and 98 agreed to participate only in an assessment control group. Psychological disorders were evaluated at baseline, 6-, 12-, 18-, and 24-month assessments. During the 2-year follow-up period, 12 students in the assessment-only group experienced an initial depressive disorder versus 2 in the prevention group. Survival analyses indicated a significantly lower rate of initial episodes of depressive disorders, χ²(1) = 4.261, p = .039, among the prevention group participants compared to the assessment only comparison group. The hazard ratio was .207, and the NNT was 11. Survival analyses indicated no significant differences between the prevention condition and the assessment only condition in the occurrence of other psychiatric disorders, χ2(1) = 1.080, p =.299. The findings indicate the program can be successfully adapted for use in Portuguese schools, and they provide a preliminary indication that those "at-risk" adolescents who chose to participate in the program, compared to those who chose to participate only in the assessments, developed fewer initial episodes of depressive disorders over the course of 24 months. The program effects were similar to the outcomes of the prior study of this program in Iceland. As in the Icelandic version of the program, its effects appeared to be specific to the depressive disorders for which the program was designed.

[Prevalence and distribution of hepatitis B virus genotype D in Galicia (northwest of Spain): influence of age, sex and origin]

OBJECTIVE

Phylogenetically, hepatitis B virus (HBV) is classified into genotypes and subgenotypes used for epidemiological studies. The aim of this study is to know the distribution of HBV subgenotypes D in our environment.

METHODS

From 401 patients HBV surface antigen positive, HBV DNA-positive, partial HBV-DNA S gene was amplified, sequenced and analysed using geno2pheno (hbv) (Max-Planck Institute) on line application.

RESULTS

We found 259 (64.6%) patients with HBV genotype D: 53 not subgenotypable, 9 (4%) D1, 61 (30%) D2, 15 (7%) D3 and 121 (59%) D4. Patients with D1 subgenotype were, on average, 23 years younger (p = 0.0001), with a higher proportion of women (p < 0.05).

CONCLUSIONS

HBV subgenotype D4 was the most prevalent in our area. Patients with D1 subgenotype came from abroad were younger than the other subgenotypes and mostly women. These results show the interest of conducting studies at HBV subgenotype level.

A systematic indoor air quality audit approach for public buildings

Good indoor air quality (IAQ) in buildings provides a comfortable and healthy environment for the occupants to work, learn, study, etc. Therefore, it is important to ascertain the IAQ status in the buildings. This study is aimed to establish and demonstrate the comprehensive IAQ audit approach for public buildings, based on Portugal national laws. Four public buildings in Portugal are used to demonstrate the IAQ audit application. The systematic approach involves the measurement of physical parameters (temperature, relative humidity, and concentration of the suspended particulate matter), monitoring of the concentrations of selected chemical indicators [carbon dioxide (CO(2)), carbon monoxide, formaldehyde, ozone, and total volatile organic compounds], and the measurements of biological indicators (bacteria and fungi). In addition, air exchange rates are measured by the concentration decay method using metabolic CO(2) as the tracer gas. The comprehensive audits indicated some situations of common IAQ problems in buildings, namely: (1) insufficient ventilation rate, (2) too high particle concentration; and (3) poor filtration effectiveness and hygienic conditions in most of the air handling units. Accordingly, a set of recommendations for the improvement of IAQ conditions were advised to the building owner/managers.

Pneumonia eosinofílica aguda com evolução para síndroma de dificuldade respiratória aguda: caso clínico

The Authors present a case of acute eosinophilic pneumonia (AEP) associated with severe acute respiratory distress syndrome in a previously healthy young adult, medicated with nitrofurantoin. AEP must be included in the differential diagnosis of community adquired pneumonia, as well as a cause of acute respiratory distress syndrome; its diagnosis is suggested by the presence of eosinophilic alveolitis in bronchoalveolar lavage fluid. The early diagnosis of AEP and corticosteroid therapy may be lifesaving.

[Drowning: tematic review and casuistic analysis in the Intensive Care Medicine Service of University Hospital of Coimbra (1989-2002)]

Drowning is a major cause of accidental deaths, especially in childrens. In this review (part one) the definition, epidemiology, pathophysiology and treatments (with an enphasis on the ressuscitation) are discussed. From 1989 to 2002 part two) we recorded the clinical course of the 19 patients vitims of submersion admited to our ICU. We conclued that the majority of patients are young (mean = 37,3 years), mortality is high (26%), but the complete recovery is possible (63%). The cardio-respiratory arrest or Glasgow Coma Scale < or = 5 were related with poor prognosis, only with 3 survivors (1 without sequels). Trauma associated lesions were observed only in one patient.

Mast cell degranulation and parenchymal cell injury in the rat mesentery

OBJECTIVE

The objective of this study was to explore the degree of parenchymal cell injury after mast cell degranulation by application of compound 48/80 (CMP 48/80) in the absence of adherent leukocytes in the rat mesentery.

METHODS

Rats were rendered leukopenic by injection of an antibody against leukocytes, and the mesentery was superfused with CMP 48/80 during intravital microscopy. The extent of cell injury was determined using a fluorescent cell-viability indicator, propidium iodide (PI). In an additional group, mast cell degranulation with CMP 48/80 was prevented by using the mast cell stabilizer Ketotifen.

RESULTS

After a reduction in the number of circulating leukocytes, mast cell degranulation produced a mild increase in parenchymal cell injury. The injury levels significantly increased when individual regions of the mesentery were compared. Stabilization of the mast cells with Ketotifen reduced the injury to below baseline values.

CONCLUSIONS

In the absence of leukocyte adhesion to the endothelium, mast cell degranulation contributes to parenchymal cell injury in the mesentery.

IgE enhances Fc epsilon receptor I expression and IgE-dependent release of histamine and lipid mediators from human umbilical cord blood-derived mast cells: synergistic effect of IL-4 and IgE on human mast cell Fc epsilon receptor I expression and mediator release

We investigated the effects of IgE versus IL-4 on Fc epsilon RI surface expression in differentiated human mast cells derived in vitro from umbilical cord blood mononuclear cells. We found that IgE (at 5 micrograms/ml) much more strikingly enhanced surface expression of Fc epsilon RI than did IL-4 (at 0.1-100 ng/ml); similar results were also obtained with differentiated mouse mast cells. However, IL-4 acted synergistically with IgE to enhance Fc epsilon RI expression in these umbilical cord blood-derived human mast cells, as well as in mouse peritoneal mast cells derived from IL-4-/- or IL-4+/+ mice. We also found that: 1) IgE-dependent enhancement of Fc epsilon RI expression was associated with a significantly enhanced ability of these human mast cells to secrete histamine, PGD2, and leukotriene C4 upon subsequent passive sensitization with IgE and challenge with anti-IgE; 2) preincubation with IL-4 enhanced IgE-dependent mediator secretion in these cells even in the absence of significant effects on Fc epsilon RI surface expression; 3) when used together with IgE, IL-4 enhanced IgE-dependent mediator secretion in human mast cells to levels greater than those observed in cells that had been preincubated with IgE alone; and 4) batches of human mast cells generated in vitro from umbilical cord blood cells derived from different donors exhibited differences in the magnitude and pattern of histamine and lipid mediator release in response to anti-IgE challenge, both under baseline conditions and after preincubation with IgE and/or IL-4.

Bacterial endotoxin is an active component of cigarette smoke

BACKGROUND

Chronic bronchitis in cigarette smokers shares many clinical and histologic features with environmental lung diseases attributed to bacterial endotoxin (lipopolysaccharide [LPS]) inhalation. Experimental LPS inhalation mimics many of the acute effects of cigarette smoke in the lower airway. Therefore, we reasoned that LPS may be a biologically active component of cigarette smoke.

DESIGN

The Limulus amebocyte lysate (LAL) assay was used to measure LPS in the tobacco and filter tip components of unsmoked 1R4F experimental cigarettes and commercially available "light" cigarettes, as well as in mainstream (MS) and sidestream (SS) smoke particles generated with an automated smoking machine and collected on ventilator mainflow filters.

SETTING AND PARTICIPANTS

Blood LPS activity and plasma cytokine concentrations were measured in groups of healthy smokers and nonsmokers who reported to the walk-in clinic at the Baltimore VA Medical Center for unrelated complaints.

MEASUREMENTS

Blood LPS levels were measured by LAL assay and plasma levels of tumor necrosis factor-alpha (TNF-alpha), interleukin 6 (IL-6), soluble TNF receptors I and II (sTNFR I and sTNFR II) were measured by enzyme-linked immunosorbent assay.

RESULTS

Bioactive LPS was detected in both the tobacco portion (1R4F, 17.8+/-1.0 microg/cigarette; light, 26.8+/-7.3 microg/cigarette [mean+/-SE]) and filter tips (1R4F, 0.67+/-0.55 microg/cigarette; light, 0.70+/-0.39 microg/cigarette) of cigarettes. Bioactive LPS was also detected in both MS (1R4F, 120+/-64 ng/cigarette; light: 45.3+/-16 ng/cigarette) and SS smoke (1R4F, 18+/-1.5 ng/cigarette; light: 75+/-49 ng/cigarette). Although systemic absorption of inhaled LPS may occur, we failed to detect any differences between nonsmokers and smokers in median blood LPS levels (median values, 66.75 and 72.1 pg/mL, respectively; p = 0.55) or plasma concentrations of TNF-alpha (0 vs 0 pg/mL, respectively; p = 0.71), sTNFR I(1,469 vs 1,576 pg/mL, respectively), sTNFR II (2,011 vs 3,110 pg/mL, respectively), or IL-6 (8.8 vs 0 pg/mL, respectively; p = 0.20).

CONCLUSIONS

Smoking one pack of cigarettes per day delivers a dose of respirable LPS that is comparable to the levels of LPS associated with adverse health effects in cotton textile workers. Thus, we suggest that the bioactive LPS in cigarette smoke may contribute to the pathogenesis of chronic bronchitis that develops in susceptible cigarette smokers.

Ultrastructural analysis of human skin biopsy specimens from patients receiving recombinant human stem cell factor: subcutaneous injection of rhSCF induces dermal mast cell degranulation and granulocyte recruitment at the injection site

We performed an ultrastructural analysis of 10 skin biopsy specimens that had been obtained from three women who were undergoing daily subcutaneous dosing with recombinant methionyl-human stem cell factor (rhSCF) as part of a phase I clinical trial. The biopsy specimens were obtained at sites of subcutaneous administration of rhSCF, within approximately 1 to 2 hours of rhSCF injection, and, at the same time, at contralateral control sites that had not been directly injected with rhSCF. We previously reported that subcutaneous dosing with rhSCF in these subjects induced the local development of a wheal and flare response, which was associated with evidence of mast cell degranulation, as well as a systemic increase in numbers of cutaneous mast cells. The present electron microscopic analysis revealed that all biopsies of swollen, erythematous rhSCF-injected sites exhibited anaphylactic degranulation of both mature and immature mast cells, an acute inflammatory response characterized by the migration of neutrophils, basophils (some of which exhibited evidence of piecemeal degranulation), and eosinophils through blood vessel walls into the perivascular and extravascular spaces, and edema and fibrin deposition within the interstitium. By contrast, the control biopsies contained no evidence of mast cell degranulation or acute inflammation. However, both control and rhSCF-injected sites exhibited mast cells that were undergoing granule building and maturation. Thus at the doses tested in these subjects, subcutaneous injection of rhSCF induced anaphylactic-type degranulation of dermal mast cells at the injection site, with an acute inflammatory response that was associated with the recruitment of granulocytes. By contrast, mast cells at sites distant from those directly injected with rhSCF exhibited no evidence of enhanced secretion.

Mechanisms of cell injury in rat mesentery and cremaster muscle

The events responsible for cell injury after a tissue stimulation are only incompletely understood. The purpose of this study was to examine mechanisms of cell injury in two tissues, rat mesentery and cremaster muscle, after tissue stimulation with N-formylmethionyl-leucyl-phenylalanine (FMLP) and platelet-activating factor (PAF). The response was studied in the same animal in random order using normal and leukopenic rats. The tissues were exteriorized after pentobarbital anesthesia. Five to six vascularized areas were chosen in each tissue, and cell injury and hydroperoxide production were assessed visually by continuous superfusion with 1 microM propidium iodide and 5 microM dichlorofluorescin diacetate (DCFH), respectively. FMLP (1 x 10(-8) M) and then PAF (1 x 10(-8) M) were added to the superfusate, and measurements were made at several time points. The second tissue was then examined using the same protocol. In the cremaster, there was little hydroperoxide production, and the tissue injury was eliminated after leukopenia. Leukopenia had no effect on tissue injury in the mesentery. Although hydroperoxide production was observed, there was no correlation between it and the tissue injury. The level of preactivation showed no correlation with either tissue injury or hydroperoxide production. In light of these results, mast cell degranulation may be an important mechanism of tissue injury in the mesentery.

The cells of the allergic response: mast cells, basophils, and eosinophils

Mast cells, basophils, and eosinophils have long been regarded as important effector cells in allergic disorders. Indeed, it is thought that the cells' cytoplasmic granule-associated or lipid mediators contribute to many of the signs and symptoms that are characteristic of these diseases. Mast cells, basophils, and eosinophils also probably contribute to protective host responses, especially to parasites. In addition, recent evidence shows that mast cells, basophils, and eosinophils can secrete a wide spectrum of cytokines and, in some cases, express functions that may permit them to regulate the development or perpetuation of allergic responses. Thus, mast cells, basophils, and eosinophils may express immunoregulatory activities, as well as serve as effector cells.

Diamine oxidase-gold ultrastructural localization of histamine in human skin biopsies containing mast cells stimulated to degranulate in vivo by exposure to recombinant human stem cell factor

Stem cell factor (SCF) has a major role in hematopoiesis and in the regulation of mast cell development and function. For example, recombinant human SCF (rhSCF) can induce the development of human mast cells from precursor cells in vitro, stimulate mediator release from human skin mast cells in vitro, and promote both the development and functional activation of human skin mast cells in vivo. In the present study, we used a new ultrastructural enzyme-affinity method, employing diamine oxidase (DAO)-conjugated gold particles (DAO-gold), to detect histamine in skin biopsies obtained from patients with breast carcinomas who were receiving daily subcutaneous (SC) injections of rhSCF in a phase I study of this cytokine. We examined control biopsies obtained at sites remote from rhSCF injection as well as biopsies of rhSCF-injected skin that were obtained within 2 hours and 30 minutes of the SC injection of rhSCF at that site. The rhSCF-injected sites (which clinically exhibited a wheal-and-flare response), but not the control sites, contained mast cells undergoing regulated secretion by granule extrusion. The DAO-gold-affinity method detected histamine in electron-dense granules of mast cells in control and injected skin biopsies; however, the altered matrix of membrane-free, extruded mast cell granules was largely unreactive with DAO-gold. Notably, DAO-gold bound strongly to fibrin deposits and collagen fibers that were adjacent to degranulated mast cells. These findings represent the first morphologic evidence of histamine secretion by classical granule exocytosis in human mast cells in vivo.

Production of macrophage inflammatory protein-1alpha by human mast cells: increased anti-IgE-dependent secretion after IgE-dependent enhancement of mast cell IgE-binding ability

The contributions of mast cells to the pathology of allergic diseases, as well as to the expression of immunoglobulin E (IgE)-dependent host responses to parasites, reflect both the amounts and types of cytokines and other mediators that are released by these cells in such settings. Whereas mast cells cannot intrinsically express immunologically specific functions, the binding of IgE to high-affinity IgE receptors (Fc epsilonRI) on the surface of mast cells primes these cells to secrete cytokines and other biologically active products upon subsequent exposure to specific antigens. We now report that both HMC-1, a growth factor-independent human mast cell leukemia cell line, and growth factor-dependent human umbilical cord blood-derived mast cells can secrete the multifunctional C-C chemokine, macrophage inflammatory protein-1alpha (MIP-1alpha). In addition, we found that in vitro exposure of human umbilical cord blood-derived mast cells to concentrations of IgE within the range observed in the serum of subjects with allergic diseases or parasite infections, which markedly up-regulates the ability of these cells to bind IgE to their surface, also significantly enhances the ability of the cells to secrete MIP-1alpha upon subsequent passive sensitization with IgE and challenge with anti-IgE. Thus, IgE-dependent enhancement of human mast cell IgE-binding ability permits these cells to respond to Fc epsilonRI-dependent challenge with significantly increased secretion of MIP-1alpha, a chemokine that can have diverse functions in inflammation, allergic reactions, and host responses to infection.

Recombinant methionyl human stem cell factor and filgrastim for peripheral blood progenitor cell mobilization and transplantation in non-Hodgkin's lymphoma patients--results of a phase I/II trial

To examine the safety and efficacy of recombinant-methionyl human stem cell factor (r-metHuSCF), 38 patients with intermediate-grade or immunoblastic high-grade non-Hodgkin's lymphoma who were eligible for autologous transplantation were randomized to receive r-metHuSCF (5, 10, 15, or 20 microg/kg/d) plus Filgrastim (10 microg/kg/d) or Filgrastim (10 microg/kg/d) alone to mobilize peripheral blood progenitor cells. Subcutaneous administration of r-metHuSCF was well tolerated in conjunction with a multi-agent pre-medication regimen; local injection site reactions were the most commonly seen adverse event. The total mononuclear cell count, CD34+ cell content, granulocyte-macrophage colony-forming cells (GM-CFC), and burst-forming units-erythroid (BFU-E) per kilogram in the apheresis product was similar when all patients were analyzed by treatment cohort and mobilization regimen (Filgrastim or r-metHuSCF in combination with Filgrastim); however, when prior chemotherapy was taken into account in a supplementary analysis, clinically important differences were observed. Extensive prior therapy was defined as the amount of exposure to specific stem cell toxic chemotherapeutic agents that patients received. These agents include procarbazine, nitrogen mustard, melphalan, nitrosoureas (> or = 2 cycles of any of these drugs) or greater than 7.5 g of cytosine arabinoside. In these patients, there was an increased number of CD34+ cells (1.76 v 0.28 x 10(6)/kg), GM-CFC (20.5 v 5.0 x 10(4)/kg), and BFU-E (36.9 v 8.9 x 10(4)/kg) in patients receiving r-metHuSCF and Filgrastim (N = 18) compared with Filgrastim alone (N = 5). These patients also had a decreased time to an untransfused platelet count of 20 x 10(9)/L that was 10.5 days shorter in the patients who received r-metHuSCF and Filgrastim (12.5 v 23 days). These differences were not found to be statistically significant, possibly because of small size, but are clinically important.

TNF alpha is important in human lung allergic reactions

Tumor necrosis factor alpha (TNF alpha) is a potentially important cytokine in allergic respiratory reactions since it is released by mast cells and eosinophils, and it can promote mediator and cytokine release, adhesion molecule expression, and granulocyte migration. Therefore, we induced an IgE-mediated response in human lung samples and studied: (1) whether TNF alpha was produced in sufficient quantities to promote granulocyte migration; and (2) which cells expressed mRNA for TNF alpha using in situ hybridization. Lung fragments (from thoracotomy) were treated for 30 min with either anti-IgE, 1:100 dilution, or buffer (control). Anti-IgE treatment of 16 lungs resulted in greater than 4-fold increase in histamine release and the significant production of chemotactic activity. The chemotactic activity generated induced dose-responsive neutrophil and eosinophil migration through naked filters and endothelial and pulmonary epithelial monolayers. Fourteen of 16 samples had a significant increase in TNF alpha subsequent to anti-IgE treatment (P < 0.05). Anti-TNF alpha antibody (4 micrograms/ml) inhibited about 25% of the neutrophil chemotactic activity in supernatants from anti-IgE treated lungs. TNF alpha at a concentration measured after anti-IgE treatment of lung samples (50 pg/ml) induced neutrophil transendothelial migration. Finally, we found that anti-IgE treatment led to an increase in TNF alpha mRNA-positive cells by in situ hybridization (1.6/ mm2 experimental versus 0.5/mm2 control), some of which were eosinophils. Thus, human lung IgE-mediated responses in vitro results in: (1) release of TNF alpha in amounts sufficient to effect a biologic response, granulocyte chemotaxis: and (2) upregulation of mRNA for TNF alpha in eosinophils and other cells. These findings suggest that TNF alpha is an important effector molecule in the pathogenesis of allergic respiratory reactions.

Recombinant human stem cell factor (kit ligand) promotes human mast cell and melanocyte hyperplasia and functional activation in vivo

Stem cell factor (SCF), also known as mast cell growth factor, kit ligand, and steel factor, is the ligand for the tyrosine kinase receptor (SCFR) that is encoded by the c-kit proto-oncogene. We analyzed the effects of recombinant human SCF (r-hSCF, 5-50 micrograms/kg/day, injected subcutaneously) on mast cells and melanocytes in a phase I study of 10 patients with advanced breast carcinoma. A wheal and flare reaction developed at each r-hSCF injection site; by electron microscopy, most dermal mast cells at these sites exhibited extensive, anaphylactic-type degranulation. A 14-d course of r-hSCF significantly increased dermal mast cell density at sites distant to those injected with the cytokine and also increased both urinary levels of the major histamine metabolite, methyl-histamine, and serum levels of mast cell alpha-tryptase. Five subjects developed areas of persistent hyperpigmentation at r-hSCF injection sites; by light microscopy, these sites exhibited markedly increased epidermal melanization and increased numbers of melanocytes. The demonstration that r-hSCF can promote both the hyperplasia and the functional activation of human mast cells and melanocytes in vivo has implications for our understanding of the role of endogenous SCF in health and disease. These findings also indicate that the interaction between SCF and its receptor represents a potential therapeutic target for regulating the numbers and functional activity of both mast cells and cutaneous melanocytes.

Regulation of mouse and human mast cell development, survival and function by stem cell factor, the ligand for the c-kit receptor

Stem cell factor (SCF), the ligand for the receptor (SCFR) that is encoded by the c-kit proto-oncogene, has many important effects in mouse and human mast cell development, survival, and function. SCF can promote mast cell survival by suppressing apoptosis, induce mast cell hyperplasia in murine rodents, experimental primates and humans, directly induce SCFR-dependent mast cell mediator release, and significantly modulate the extent of mast cell activation by Fc epsilon RI-dependent mechanisms. These findings raise several clinical issues and, in some cases, point to potentially significant therapeutic opportunities.

Immunocytochemical localization of a growth-associated protein (GAP-43) in rat adrenal gland

We have localized at light and electron-microscopic level the growth-associated protein GAP-43 in adrenal gland using single and double labelling immunocytochemistry. Clusters of GAP-43-immunofluorescent chromaffin cells and many immunofluorescent fibres were observed in the medulla. GAP-43-immunoreactive fibres also formed a plexus under the capsule, crossed the cortex and ramified in the zona reticulata. Double labelled sections showed the coexpression of GAP-43 with a subpopulation of tyrosine hydroxylase- and of dopamine-beta-hydroxylase-immunoreactive chromaffin cells. Dual colour immunofluorescence for GAP-43 and calcitonin gene-related peptide (CGRP) revealed that some of the GAP-43-immunoreactive fibres also express CGRP. Pre-embedding electron microscopy showed GAP-43 immunoreactivity associated with the plasma membranes and cytoplasm of noradrenaline-producing chromaffin cells, and with processes of nonmyelin-forming Schwann cells. Immunoreactive unmyelinated axons and terminals were also observed. The immunostained terminals made symmetrical synaptic contacts with chromaffin cells. Immunoreactive unmyelinated fibres and small terminals were present in the cortex. Our results show that GAP-43 is expressed in noradrenergic chromaffin cells and in various types of nerve fibres that innervate the adrenal. Likely origins for these fibres include preganglionic sympathetic fibres which innervate chromaffin cells, postganglionic sympathetic fibres in the cortex, and CGRP containing sensory fibres.

Human eosinophils can express the cytokines tumor necrosis factor-alpha and macrophage inflammatory protein-1 alpha

By in situ hybridization, 44-100% of the blood eosinophils from five patients with hypereosinophilia and four normal subjects exhibited intense hybridization signals for TNF-alpha mRNA. TNF-alpha protein was detectable by immunohistochemistry in blood eosinophils of hypereosinophilic subjects, and purified blood eosinophils from three atopic donors exhibited cycloheximide-inhibitable spontaneous release of TNF-alpha in vitro. Many blood eosinophils (39-91%) from hypereosinophilic donors exhibited intense labeling for macrophage inflammatory protein-1 alpha (MIP-1 alpha) mRNA, whereas eosinophils of normal donors demonstrated only weak or undetectable hybridization signals for MIP-1 alpha mRNA. Most tissue eosinophils infiltrating nasal polyps were strongly positive for both TNF-alpha and MIP-1 alpha mRNA. By Northern blot analysis, highly enriched blood eosinophils from a patient with the idiopathic hypereosinophilic syndrome exhibited differential expression of TNF-alpha and MIP-1 alpha mRNA. These findings indicate that human eosinophils represent a potential source of TNF-alpha and MIP-1 alpha, that levels of expression of mRNA for both cytokines are high in the blood eosinophils of hypereosinophilic donors and in eosinophils infiltrating nasal polyps, that the eosinophils of normal subjects express higher levels of TNF-alpha than MIP-1 alpha mRNA, and that eosinophils purified from the blood of atopic donors can release TNF-alpha in vitro.

Immortalization of mouse bone marrow-derived mast cells with Ad12-SV40 virus

Mast cells arise in cultures of murine bone marrow in medium supplemented with interleukin-3 (IL-3). In the present study, we report the development of long-term mast cell lines from murine bone-marrow-derived cultured mast cells (BMCMC) following inoculation with adenovirus 12-simian virus 40 (Ad12-SV40) hybrid virus. One culture of Ad12-SV40 immortalized BMCMC (designated as MCP-5) was selected for further analysis. These transformed cells appear similar in morphology and histochemistry to the primary BMCMC from which they are derived and did not shed infectious virus into the culture supernatants. In addition, these cells synthesize predominantly chondroitin sulfate proteoglycans and contain histamine which is released following a physiologic stimulus. Limiting-dilution single-cell cloning produced five independent mast cell lines (MCP-5.1 to MCP-5.5). Southern blot analysis of genomic DNA isolated from these single-cell clones demonstrates different patterns of viral integration in all the five clones. All clones retain responsiveness to an exogenous source of IL-3 for growth and proliferation. Each single-cell clone also demonstrates a unique pattern of cytokine gene expression in response to calcium ionophore A23187 and phorbol-12-myristate-13-acetate. This suggests that within a culture of BMCMC there are differences in cytokine gene expression that vary from one cell to another. The availability of immortalized mast cell lines derived from murine bone marrow which retain their growth factor responsiveness and the ability to respond to degranulating stimuli should facilitate future studies of mast cell biology.

Aphidicolin-induced proliferative arrest of murine mast cells: morphological and biochemical changes are not accompanied by alterations in cytokine gene induction

Investigations of mast cell biology have often used immortalized cultured cells which are continuously proliferating. In vivo, however, only 2% or fewer tissue mast cells are actively dividing. We used aphidicolin, an inhibitor of DNA polymerase to induce a proliferative arrest of murine mast cells characterized by an inhibition of cell division and thymidine incorporation, with accumulation of cells in G1 and early S phase of the cell cycle. Uridine incorporation and cell viability were not significantly impaired. DNA synthesis and cell division both resumed rapidly upon removal of the drug. Morphometric analysis demonstrated that cell size, granule size, and number of granules per cell were all increased in aphidicolin-treated cells. Proliferative arrest also produced a 14-fold increase in cellular histamine content, but did not alter the proteoglycans synthesized by the cell. The level of c-myc mRNA was reduced in aphidicolin-arrested cells, but returned to the level observed in untreated cells within 1 hr of removal of the drug. In contrast, the constitutive steady-state RNA levels of tumour necrosis factor-alpha (TNF-alpha), B2-microglobulin, actin, and the c-Ha-ras and c-fes protooncogenes were not altered. Aphidicolin-induced proliferative arrest did not prevent the induction of TNF-alpha, interleukin-6 (IL-6) and c-fos genes in response to calcium ionophore. Both the magnitude and induction kinetics of these messages were similar in aphidicolin-treated and untreated cells. We conclude that proliferative arrest results in morphological and biochemical changes suggestive of cellular maturation, but inhibition of cell division alone is not sufficient to alter mast cell phenotype. Although optimal c-myc expression appears to require active proliferation, cytokine gene induction can occur in non-dividing cells. These data suggest that the proliferative quiescence of in vivo mast cells should not preclude their involvement in biological events via elaboration of multi-functional cytokines.

Mast cell adhesion to fibronectin

The MCP-5 murine mast cell line, as well as primary bone marrow-derived cultured mast cells (BMCMC), are demonstrated to bind to fibronectin, a ubiquitous adhesion protein of the extracellular matrix. BMCMC required activation by phorbol myristate acetate (PMA) to adhere to fibronectin, whereas MCP-5 displayed spontaneous adherence. The binding of both MCP-5 and BMCMC was dose dependent, with maximal adhesion at a fibronectin concentration of 20 micrograms/ml. The 120,000 molecular weight (MW) proteolytic fragment of fibronectin containing the RGDS cell attachment site was able to substitute for the native fibronectin molecule in promoting mast cell attachment. Mast cell adhesion to fibronectin, in addition, could be inhibited by the RGDS peptide alone. These data suggest that, in addition to the previously described mast cell-laminin interactions, mast cells also adhere to fibronectin, thus providing further insight into their tissue localization and possible roles in processes such as wound healing and fibrosis.

Restriction map of corynebacteriophages beta c and beta vir and physical localization of the diphtheria tox operon

The BamHI, EcoRI, HindIII, and KpnI restriction endonuclease maps of corynebacteriophage beta c and beta vir were constructed. beta vir appeared to be identical to beta c, except for an approximate 1-kilobase deletion that removed a BamHI site, two KpnI sites, and three EcoRI restriction sites. The diphtheria tox operon was located by hybridizing in vitro 32P-labeled tox messenger ribonucleic acid to blots of endonuclease-digested beta deoxyribonucleic acids. The messenger ribonucleic acid probe was found to hybridize to a 2.1-kilobase region of the beta genome. Since approximately 1.9 kilobases is required to encode prodiphtheria toxin, the data presented strongly suggest that the tox operon of beta is monocistronic.