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Biomedical subjects

F C Schmalstieg

Publications and source records attributed to F C Schmalstieg.

At least 37 records · Page 2Linked to original sources
PubMed1994

Oxygen-induced lung injury in the guinea pig proceeds through CD18-independent mechanisms.

The pathogenesis of pulmonary oxygen toxicity is postulated to be related in part to neutrophil-mediated injury. This study examined the effect of a monoclonal antibody directed against the CD11a,b,c/CD18 glycoprotein complex (beta 2 leukocyte integrins) on oxygen-induced lung injury. M8, a monoclonal antibody that binds to the beta chain of the guinea pig leukocyte integrins that facilitate neutrophil adherence to vascular endothelium, was injected into adult guinea pigs prior to and during exposure to > 98% oxygen. Control oxygen-exposed animals were injected with a noninhibitory antibody to the CD18 complex or with saline. Survival in oxygen was similar for animals treated with M8 when compared with those treated with saline (102 versus 105 h, respectively, NS). Pulmonary edema as assessed by protein in the supernatant of bronchoalveolar lavage fluid (BALF) was higher in the three groups of oxygen-exposed animals than in the air-exposed groups (p < 0.01), but it did not differ between the M8 antibody treatment group and the other oxygen-exposed groups. M8 antibody treatment did not decrease hyperoxia-induced neutrophil accumulation into the lung as assessed by myeloperoxidase activity (MPO) in lung homogenates or by neutrophil counts in histologic specimens. M8 antibody also did not decrease neutrophil counts or MPO in alveolar lavage fluid, both of which were significantly elevated in all oxygen-exposed groups. These results suggest that hyperoxia-induced neutrophil migration into the lung and acute lung injury occurs by CD18-independent processes in the guinea pig model of pulmonary oxygen toxicity.

Animals↗
PubMed1994

Immunologic protection of the premature newborn by human milk.

During the past decade, considerable evidence has accrued regarding the immunologic uniqueness of human milk and of the important role that the immune system in human milk plays in protecting not only the mature, healthy newborn, but also the premature infant who is more prone to infections and the damage caused by inflammatory processes. However, there is a great deal more to learn about the prophylactic and therapeutic uses of human milk in low birth weight infants, including (1) the status of many of the host defense factors in preterm milk, (2) how to preserve the protective agents in human milk during processing and storage, (3) the dose and duration of treatment with human preterm or mature milk that will be needed to protect against a particular disorder, (4) whether non-maternal milk is as efficacious as maternal milk for these infants, and (5) in view of the concern of potential graft versus host reactions, whether it is desirable or contraindicated to maintain the leukocytes in human milk used to feed premature infants. These questions are not easily answered, but will be worthy considerations by neonatologists, clinical immunologists, epidemiologists, and others who are concerned with providing optimal nutritional/immunologic support for the premature infant.

Anti-Inflammatory Agents↗
PubMed1993

Activated neutrophils and neutrophil activators in human milk: increased expression of CD11b and decreased expression of L-selectin.

Human milk neutrophils and macrophages were examined by flow cytometry to determine whether they displayed phenotypic markers of activation. The markers were CD11b and L-selectin, which are increased or shed, respectively, from the surface of activated neutrophils. Phenotypic features of milk neutrophils and macrophages were similar to blood neutrophils stimulated with fMLP: plasma membrane expression of CD11b was increased and L-selectin was decreased. After blood neutrophils were incubated in acellular milk, their expression of CD11b increased and L-selectin decreased. The activation was not affected by trypsin but was significantly decreased by treating acellular milk with chloroform or ether. Sedimentation studies suggested that particulate fractions of milk were active. Further, the activation was partly blocked by treating target blood neutrophils with cytochalasin B. Thus, human milk neutrophils are activated, and the activation may be due partly to phagocytosis of membranous structures in milk.

Cell Adhesion Molecules↗
PubMed1993

Interleukin-6 in human milk.

Interleukin-6 (IL-6) in human milk collected during the first 2 days of lactation was investigated by a competitive radioimmunoassay (RIA) and column chromatography. The concentrations of IL-6 in the aqueous phase of fresh human milk were 151 +/- 89 pg/ml. The concentrations of IL-6 in milk increased after storage at 4 degrees C and decreased after storage at -20 degrees C (P < 0.01). Column chromatography revealed two molecular weight peaks of IL-6 in human milk, the first > or = 100 kDa and the second between 25 and 30 kDa. The 25-30-kDa peak corresponded to known isoforms of human IL-6 and to the elution pattern for 125I-labeled recombinant human IL-6, whereas the higher molecular weight peak may be in keeping with a bound or compartmentalized form of that cytokine. The precise molecular forms of this protein, the compartmentalization of or binding proteins for this cytokine and the in vivo effects of IL-6 in human milk upon the mammary gland or the recipient infant remain to be explored.

Adolescent↗
PubMed1993

Discovery of the leukocyte adherence defect--a historical perspective.

Leukocyte adherence deficiency (LAD) is characterized by bacterial infections at peripheral tissue sites whose defense requires exit of neutrophils from the vasculature. LAD is unique in that one of the basic and common cell properties, adherence, is involved in this defect in host defense. The molecular understanding of LAD catalyzed a continuing revolution in the investigation and understanding of cell adherence phenomena inside and outside of the immune system. The explosive gain of knowledge directly attributable to the recognition of LAD may make this disease the most important inborn error of host defense yet recognized. The recognition of this defect through the interaction of a number of investigators is explored in this report. An attempt is made to reveal the background events that made the discovery of this defect possible. The relationship between the understanding of the physiology of this disease and the rapid understanding of the molecular defect is examined. Finally, the significance of this disease and its understanding in relation to biologic discovery in general are discussed.

Cell Adhesion↗
PubMed1992

Activated and memory T lymphocytes in human milk.

Since activated macrophages and cytokines are found in human milk (HM), a flow cytometry study was conducted to determine whether T cells in HM display phenotypic markers of recent or previous activation. HM was collected during the first 3 d of lactation. The Paint-a-Gate program was used to optimize gating on the lymphocyte population. A mean +/- 1 SD of 4 +/- 3% of total HM leukocytes were lymphocytes and 96 +/- 3% were macrophages and granulocytes (N = 33 subjects). HM lymphocyte populations were further analyzed in five subjects. T cells (CD3+) represented 83 +/- 11% and B cells (CD19+) were 6 +/- 4% of HM lymphocytes. The mean CD4/CD8 ratio of T cells in HM was 0.88 (range 0.40-1.25). This ratio was significantly decreased compared to the peripheral blood (PB) of control adults (P less than 0.02) and postpartum women (P less than 0.02), due mostly to a significant increase in CD8+ CD3+ cells in HM compared to the PB of control adults (P less than 0.002) and postpartum women (P less than 0.05). T cells bearing markers of recent activation were significantly increased in HM compared to the PB of control adults: 85 +/- 7% of CD3+ cells in HM were HLA-DR+ (controls, 10 +/- 4%; P less than 0.001), and 15 +/- 6% of CD3+ cells in HM were IL-2R+ (controls, 6 +/- 2%; P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, Differentiation, T-Lymphocyte↗
PubMed1992

Repertoire of V alpha and V beta regions of T cell antigen receptors on CD4+ and CD8+ peripheral blood T cells in a novel X-linked combined immunodeficiency disease.

The repertoire of V regions of alpha/beta+ T cell receptor (TcR) on CD4+ and CD8+ T cells from the peripheral blood of six patients with a novel X-linked combined immunodeficiency was investigated by flow cytometry. The relative frequencies of V region subfamilies V alpha 2a on CD4+ T lymphocytes and V beta 5b and V beta 12a on CD8+ T lymphocytes from the peripheral blood from the affected males were decreased significantly. Also, the relative frequencies of certain other V region subfamilies on CD4+ or CD8+ T cells from the peripheral blood of some patients were either considerably below or above the ranges found in normal subjects. Although there may be other explanations including an extrathymic event, we suggest that the abnormalities in the TcR repertoire of peripheral blood T cells are consistent with a dysregulation of the intrathymic maturation/selection of T cells that leads to deficiencies in T cell populations in the peripheral blood of males with this disease.

CD4-Positive T-Lymphocytes↗
PubMed1992

Postnatal development of T lymphocytes in a novel X-linked immunodeficiency disease.

We previously reported an X-linked combined immunodeficiency disease (CID) characterized by immune deficiencies and complicating infections that were more moderate than those found in severe CID (SCID). Since other unstudied males in the family died in infancy, we questioned whether this T cell defect was more profound in early life. Subsequently, the development of blood T cells in an affected newborn male was examined. T cells were virtually undetectable at 48 hr. Over the next several months, CD4+ T cells (principally CD45RO+) rose to levels similar to those found in older affected males, but CD8+ T cells developed more slowly and never attained levels found in other affected males. Thus, this disease in early life mimics SCID and may pose a higher risk of fatal infections to affected individuals during that period. Finally, we speculate that the genetic defect may disrupt intrathymic development or selection of T cells.

Antibodies, Bacterial↗
PubMed1992

Tumor necrosis factor-alpha in human milk.

We previously demonstrated that certain biologic activities in human milk were partially blocked by antibodies directed against human tumor necrosis factor-alpha (TNF-alpha). In this study, immunochemical methods were used to verify the presence of TNF-alpha in human milk obtained during the first few days of lactation. Gel filtration revealed the presence of TNF-alpha by RIA in molecular weight fractions between 80 and 195 kD. TNF-alpha could not be detected consistently by conventional Western blotting or cytotoxic assays. Although immunoreactive bands were detected by a Western blot-125I protein A technique in TNF-alpha-positive fractions from gel filtration, those bands proved to be nonspecific. TNF-alpha in milk was reliably quantified by the competitive RIA. Those studies revealed that the concentrations of TNF-alpha in milk were 620 +/- 183 pg/mL. Although RNA to TNF-alpha was detected in milk leukocytes by Northern blotting, little TNF-alpha was found in those cells before or after stimulation with N-formyl-l-methionyl-l-leucyl-l-phenylalanine or 4 beta-phorbol-12 beta-myristate-13 alpha-acetate. The origin of this cytokine in human milk remains unclear. Nevertheless, this study suggests that TNF-alpha is present in early human milk in sufficient quantities to exert possible biologic effects upon the mammary gland of the mother or the immune system of the infant.

Adolescent↗
PubMed1990

Subcellular distribution and mobilization of MAC-1 (CD11b/CD18) in neonatal neutrophils.

The CD11b/CD18 (Mac-1) heterodimeric surface glycoprotein contributes to a broad range of adherence-dependent neutrophil inflammatory functions. Previous investigations have indicated that diminished expression or regulation of Mac-1 may underlie abnormalities of stimulated adhesion and chemotaxis of neonatal neutrophils in vitro and inflammatory deficits in human neonates. To define the pathogenic mechanisms contributing to these findings, we compared the distribution and translocation of Mac-1 in subcellular fractions of neonatal and adult neutrophils before and after chemotactic stimulation. The total cell content of Mac-1 and the proportions of Mac-1 in beta fractions (vitamin B12 binding protein-rich granules), pre-gamma fractions (gelatinase-rich granules), or gamma fractions (plasma membrane) of neonatal neutrophils were comparable with those of adult neutrophils. However, after stimulation with N-formyl-methionyl-leucyl-phenylalanine (FMLP; 10 nmol/L, 37 degrees C, 15 minutes), neonatal neutrophils demonstrated (1) diminished translocation of Mac-1 from pre-gamma fractions (P less than .05), and (2) diminished surface expression of Mac-1 (P less than .05), as compared with healthy adult neutrophils. As shown in enzymatic and immunochemical assays, neonatal cells contained significantly (P less than .01) diminished levels of neutrophil gelatinase. In response to FMLP (0.1 to 10 nmol/L, 37 degrees C, 15 minutes), neonatal suspensions also released significantly (P less than .001) less gelatinase, as compared with adult neutrophil suspensions. These observations demonstrate that diminished mobilization of Mac-1 from gelatinase-rich granular pools in neonatal neutrophils is associated with abnormal surface expression of this glycoprotein after chemotactic stimulation. This abnormality may contribute, in part, to abnormal migratory properties of neonatal neutrophils in response to inflammatory stimuli.

Antigens, Differentiation↗
PubMed1990

Neutrophil adherence to isolated adult canine myocytes. Evidence for a CD18-dependent mechanism.

Cardiac myocytes were isolated from adult dogs and incubated with isolated canine neutrophils (PMN). Intercellular adhesion was low and unchanged by stimulation of the PMN with zymosan activated serum or platelet activating factor (PAF) at concentrations that significantly enhance PMN adhesion to protein-coated glass and canine endothelial cell monolayers. Intercellular adhesion was significantly increased only when both myocytes and PMN were stimulated (e.g., myocytes incubated with IL-1, tumor necrosis factor, or phorbol myristate acetate, and PMN were chemotactically stimulated). Inhibitors of protein synthesis diminished the IL-1 beta-induced effect by greater than 80%. The IL-1 beta, PAF-stimulated PMN-myocyte adhesion was associated with substantial H2O2 production. Under conditions with low PMN-myocyte adhesion (i.e., IL-1 beta alone, PAF alone, or no stimulus) H2O2 production was generally less than 5% of that occurring with high adhesion. An anti-CD18 monoclonal antibody (R15.7) inhibited stimulated PMN-myocyte adhesion by greater than 95% and reduced H2O2 production by greater than 90%. Control isotype-matched, binding, and nonbinding antibodies were without effect on adherence or H2O2 production. The results indicate that cytokine stimulation of adult myocytes induces expression of a ligand involved in CD18-dependent adherence of canine neutrophils.

Animals↗
PubMed1990

A novel X-linked combined immunodeficiency disease.

A novel X-linked combined immunodeficiency disease was found in five living males in an extended family in the United States. The age of the affected males ranged from 2.5 to 34 yr. The most prominent clinical abnormalities were a paucity of lymphoid tissue; recurrent sinusitis, otitis media, bronchitis, and pneumonia; severe varicella; and chronic papillomavirus infections. The principal immunologic features of the disorder were normal concentrations of serum immunoglobulins but restricted formation of IgG antibodies to immunogens; normal numbers of B cells and NK cells but decreased numbers of CD4+ and CD8+ T lymphocytes, particularly the CD45RA+ subpopulations; diminished proliferative responses of blood T cells to allogeneic cells, mitogens and antigens; and decreased production of IL-2 by mitogen stimulated blood lymphocytes. Thus, affected males in this family carry an abnormal gene on their X chromosome that results in a combined immunodeficiency that is distinct from previously reported disorders.

Adolescent↗
PubMed1990

Molecular definition of the bovine granulocytopathy syndrome: identification of deficiency of the Mac-1 (CD11b/CD18) glycoprotein.

Leukocytosis (34,600 WBC/microliter of blood) was detected in an apparently healthy 7-day-old Holstein heifer. Analysis of blood samples obtained over the next 41 days revealed chronic progressive neutrophilia, which peaked at greater than 85% neutrophils and exceeded 100,000 WBC/microliter. In vitro assessment of isolated blood neutrophils obtained from the heifer at 38 and 45 days of age revealed selected functional abnormalities. Endocytosis of immunoglobulin-opsonized Staphylococcus aureus and killing of this test organism by the calf's neutrophils were significantly diminished, as were phagocytosis-associated superoxide generation, chemiluminescence activity, and myeloperoxidase-catalyzed iodination. Diminished H2O2 elaboration by the calf's neutrophils was evident during ingestion of opsonized zymosan or on exposure to phorbol myristate acetate. Extracellular release (secretion) of elastase during ingestion of zymosan was also diminished, although total cell content of elastase was normal, compared with that of neutrophils from age-matched calves, and granular or other morphologic abnormalities of the calf's neutrophils were not evident by ultrastructural examination. Abnormalities of random migration were inconsistently detected, and normal or high degree of antibody-dependent cytotoxicity or natural killing by the calf's neutrophils was observed. Similar in vitro assessment of neutrophils obtained from the calf's dam revealed no functional abnormalities. The calf died at 48 days of age, with persistent fever and chronic diarrhea, despite administration of antibiotics. Histologic examination at necropsy revealed large numbers of intravascular neutrophils in most tissues, including massive neutrophil sequestration in spleen. However, a striking lack of extravascular neutrophils was evident in inflamed submucosa adjacent to intestinal ulcers heavily contaminated with enteric microorganisms. Bone marrow examination revealed diffuse myeloid hyperplasia, but no other abnormalities.

Animals↗
PubMed1989

Chemokinetic effects of exogenous and endogenous tumor necrosis factor alpha on human blood monocytes.

The possible chemokinetic effect of human tumor necrosis factor alpha (TNF-alpha) upon human monocytes was investigated by using a type 1 collagen gel system. Human recombinant TNF-alpha was found to be chemokinetic, and concentrations of that cytokine as low as 0.7 pg/microliters enhanced the movement of those leukocytes. Furthermore, we explored whether endogenous TNF-alpha stimulates monocyte movement by incubating blood monocytes with a TNF-alpha-stimulating agent, human recombinant interleukin 1, with or without antibodies to human TNF-alpha. Human recombinant interleukin 1 enhanced the motility of blood monocytes, and that effect was blocked by rabbit polyclonal antibodies to human TNF-alpha. Furthermore, the movement of blood monocytes no exposed to exogenous cytokines was decreased after incubation with anti-TNF-alpha. Thus, endogenous as well as exogenous TNF-alpha is a chemokinetic agent for human monocytes.

Adult↗
PubMed1989

Chemokinetic agents for monocytes in human milk: possible role of tumor necrosis factor-alpha.

Human milk was found to contain chemokinetic agents for human blood monocytes. The chemokinetic agents were whey proteins that were inactivated by heating at 56 degrees C for 20 min or treatment with trypsin. Three peaks of chemokinetic activity less than 60 kD in size were found by gel filtration chromatography. The chemokinetic activity of each peak obtained by gel filtration was partially blocked by polyclonal rabbit antibodies to recombinant human tumor necrosis factor-alpha (TNF-alpha). TNF-alpha, or a protein that immunologically cross-reacted with it, was also detected in human milk by blockage of the cytotoxicity of human milk by anti-TNF-alpha. Such proteins or others that elicit the release of TNF-alpha from the target cells may be responsible for the enhanced motility of human milk macrophages, and it is possible that they may alter the immunologic or metabolic activities of the alimentary tract of the recipient infant.

Female↗
PubMed1988

Quantitation of intracellular Mac-1 (CD11b/CD18) pools in human neutrophils.

The adhesive glycoprotein Mac-1 (CD11b/CD18) of the CD11/CD18 complex contributes to multiple neutrophil inflammatory functions. Activation of neutrophils by chemotactic stimuli results in a rapid, protein synthesis-independent increase in surface Mac-1 derived from incompletely defined intracellular compartments. Therefore, we developed a novel quantitative lectin immunoblot technique to define intracellular pools of Mac-1 in subcellular neutrophil fractions resolved on discontinuous Percoll gradients. In cavitates of unstimulated neutrophils, 30% and 26% of total Mac-1 was identified in beta [1.10 gm/ml; vitamin B12 binding protein (vit B12 B.P.)-rich] or pre-gamma (1.07 gm/ml; vit B12 B.P.-poor) granular fractions, respectively, whereas 24% was associated with the plasma membrane-rich gamma (1.06 gm/ml) fractions. N-formyl-methionyl-leucyl-phenylalanine (fMLP) stimulation (10(-8) M, 15 min, 37 degrees C) significantly diminished Mac-1 in pre-gamma (-18% of total, P less than 0.05) but not beta fractions (+6% of total). Under these conditions, the content of Mac-1 in gamma fractions increased 13% in association with four- to eightfold increase in surface Mac-1 expression (OKM-1 binding). These findings suggest that chemotactic stimuli increase plasma membrane and/or surface Mac-1 on human neutrophils by mobilizing a novel intracellular granule pool.

Adult↗