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PubMed1990

Comparison of cefodizime with various cephalosporins for their indirect effect on the human neutrophil oxidative burst in vitro.

Cefodizime, a 2-amino-thiazolyl cephalosporin, is reported to display in-vitro, ex-vivo and in-vivo immunomodulatory properties; in particular, it enhances the survival of mice infected with cefodizime-resistant pathogens. We have used an in-vitro model to assess the indirect effect of this drug (compared with other cephalosporins) on the neutrophil (PMN) oxidative response. Pseudomonas aeruginosa was employed as the bacterial target for cefodizime and cefotaxime (MICs greater than 128 mg/l), cefsulodin (MIC 16 mg/l) and ceftazidime (MIC 32 mg/l). After overnight growth in the presence of subinhibitory concentrations of each drug (10 mg/l), the altered filamentous P. aeruginosa induced a stronger oxidative response of PMN than untreated control bacteria. For all cephalosporins this was related to alterations of bacterial structure leading to increased deposits of antibodies and/or complement. Furthermore, increased non-opsonin dependent stimulation of the PMN oxidative burst was obtained; the strongest response was observed with cefodizime-treated P. aeruginosa in the case of low responder PMN, which displayed a deficient response after stimulation by control bacteria. The possibility that cefodizime could enhance this PMN function in opsonin-deficient patients requires further investigation.

Cefotaxime↗
PubMed2001

Whipple disease and arthritis.

Whipple disease is a chronic, multisystem, curable, bacterial infection that usually affects middle-aged men and has a wide range of clinical manifestations. The most common symptoms are weight loss and diarrhea, preceded in three quarters of cases by arthritis for a mean of 6 years. In most patients, periodic acid-Schiff staining of proximal small bowel biopsy specimens reveals inclusions within the macrophages, corresponding to bacterial structures. However, patients with various manifestations of the disease may have no gastrointestinal symptoms and negative jejunum biopsy results. Before the onset of gastrointestinal symptoms, a strong index of clinical suspicion is the key to diagnosis. The classic setting is long-term, unexplained, seronegative oligoarthritis or polyarthritis with a palindromic or relapsing course, although chronic destructive polyarthritis and spondyloarthropathy have been repeatedly reported. Identification of the Whipple bacterium, Tropheryma whippelii, has led to the development of polymerase chain reaction as a diagnostic tool in patients in the early stages of the disease or with atypical Whipple disease. This technique can be used to detect the bacterium in many tissues and fluids, including synovial tissue and fluid. The recent cultivation of the Whipple bacillus should lead to the development of serologic tests, further facilitating diagnosis. These recent major advances may show that the infection is more frequent than previously suspected and may expand the clinical spectrum of the disease. It may also allow earlier diagnosis, thereby preventing the development of the severe systemic and sometimes fatal forms of the disease.

Adolescent↗
PubMed2006

Probiotics and the immune response.

Beneficial effects exerted by probiotic bacteria in the treatment of human disease may be broadly classified as those effects which arise due to activity in the large intestine and are related to colonization or inhibition of pathogen growth; and those effects which arise in both the small and large intestine, and are related to enhancement of the host immune response and intestinal barrier function. In a strain dependent fashion, probiotic bacteria can enhance intestinal barrier function and modulate signal transduction pathways and gene expression in epithelial and immune cells. Oral administration of live probiotics and bacterial structural components can also differentially modulate dendritic cells resulting in an increased production of IL-10 and regulatory T cells. Both innate and adaptive immune responses can be modulated by probiotic bacteria.

Administration, Oral↗
PubMed1983

Muramyl peptides as possible endogenous immunopharmacological mediators.

Synthetic N-acetylmuramyl-L-alanyl-D-isoglutamine, also called MDP for muramyl dipeptide, is a copy of a fragment of bacterial peptidoglycan. Soon after the recognition of MDP as being the minimal subunit responsible for the activity of Freund's complete adjuvant, a great number of derivatives were synthesized. Because of their very low molecular weight it was hoped that they could retain selectively certain of the numerous effects produced by complex bacterial agents. Evidence was gathered showing MDP's direct effect on lymphocytes and on macrophages. The ensuing studies reviewed that MDP and several of its derivatives have marked immunopharmacological and neuropharmacological activities. Thus, besides being adjuvants, they are capable of producing hyperthermia by acting directly on thermoregulation centers or by inducing in vivo and in vitro endogenous pyrogens (EP). More recently, Krueger et al have shown that slow-wave sleep (SWS) factor was a muramyl peptide of a molecular weight close to 1,000 daltons. They have also shown that MDP and several of its synthetic analogs had a somnogenic activity. It has previously been hypothesized that several of the immunological activities of the muramyl peptides could be due to biological mimicry with endogenous products. Recent observations argue in favor of the presence of an MDP bacterial structure in mammalian mediators which increase slow-wave sleep and/or produce fever. The implications of these findings will be discussed.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1990

Diverse target antigens recognized by circulating antibodies in anti-neutrophil cytoplasm antibody-associated renal vasculitides.

Antibodies that are directed against cytoplasmic constituents of neutrophils and monocytes (anti-neutrophil cytoplasm antibodies, ANCA) have been described in Wegener's granulomatosis, microscopic polyarteritis (MPA) and some cases of segmental necrotizing glomerulonephritis (SNGN). Other antibodies occasionally described in Wegener's granulomatosis and MPA include anti-nuclear antibodies (ANA) and anti-glomerular basement membrane (GBM) antibodies. We have studied the diversity of the corresponding antigens in ANCA-associated renal diseases. Sera from 46 patients with active histologically proven Wegener's granulomatosis, MPA and SNGN were tested for ANCA by indirect immunofluorescent examination of normal peripheral blood neutrophils. Thirty-four sera (74%) were positive; 16 were associated with diffuse cytoplasmic staining (cANCA) and 18 with perinuclear staining (pANCA). In addition, five demonstrated antineutrophil-specific nuclear staining (ANNA). On Western blotting of the neutrophil extract, five sera recognized a 29-kD molecule recently identified as neutrophil proteinase 3. Two sera with typical cANCA bound to molecules of 36, 38 and 116 kD and another to a molecule of 22 kD. The final serum associated with pANCA bound to a molecule of about 12 kD. Thirteen sera out of 46 (28%) tested in an ELISA contained anti-myeloperoxidase antibodies; 10 of these were associated with pANCA and two others with ANNA. Three sera of 17 (18%) tested contained anti-elastase antibodies; these also contained anti-myeloperoxidase antibodies and were associated with pANCA. However, eight sera with pANCA were negative for anti-myeloperoxidase antibodies and three of these were also negative for anti-elastase antibodies, suggesting further unidentified target antigen or antigens associated with the pANCA. Fifteen of the 34 sera positive for ANCA also demonstrated anti-nuclear staining on Hep-2 cells (53%) in a speckled, homogeneous, or nucleolar pattern. ANA were significantly associated with the presence of pANCA (P less than 0.01), and levels of ANA and ANCA fell in parallel after treatment. One serum with a pANCA was also positive for anti-GBM antibodies. Inhibition studies using ELISAs for anti-GBM antibodies indicated that there was no cross-reactivity between target molecules recognized by these antibodies. The diversity of target molecules recognized by ANCA suggests that cross-reactivity with bacterial structures is less likely as the primary aetiological event in the development of these antibodies than tissue destruction; and that cross-reactivity with vascular endothelium is also unlikely as the pathogenetic basis of vessel disease.

Antibodies, Antinuclear↗
PubMed1992

A comparison of three methods for estimating dental plaque removal from individual teeth.

The purpose of this study was to determine the efficiency of dental plaque removal, in vitro, by physical force. Of the 3 methods used, turbidity was the most sensitive for measuring microgram amounts of plaque. Air-dried weight and dental plaque imprint assays (DPIA) complemented turbidity measurements by providing a weight standard and a new method for visualizing plaque bacterial structure before the stained imprint was transformed into numerical data. The amount of dental plaque removed from a tooth by physical force can be measured and described as a percentage of the total removable plaque on that tooth.

Analysis of Variance↗
PubMed1996

Regulation of chemokine gene expression in human endothelial cells by proinflammatory cytokines and Borrelia burgdorferi.

Chemokines play a central role in the process of leukocyte recruitment to tissues. By their chemotactic activity they guide leukocytes to the site of infection/injury. Chemokines have been suggested to trigger firm adhesion of leukocytes to activated endothelial cells as well as the subsequent diapedesis. For these functions, chemokines produced by EC are particularly well suited. Our experiments with proinflammatory stimuli demonstrate that chemokines are induced in EC by a variety of stimuli including inflammatory cytokines and bacterial structures such as LPS and preparations of B. burgdorferi. The induction of chemokines by all of these agents occurs rapidly and does not require new protein synthesis. Two chemokines, MCP-1 and IL-8, respond to very low doses (0.1-1 U/ml) of proinflammatory cytokines which is important at the beginning of an immune response when soluble inflammatory mediators might still be limiting. The chemokines RANTES, IP-10, and mig show synergistic induction by low doses (1 U/ml) of several inflammatory mediators, which again is important when only limiting amounts of inflammatory stimuli are present. The upregulation of six chemokine genes as well as genes encoding adhesion molecules in two cell types, EC and fibroblasts, by B. burgdorferi suggests that chemokines might play a central role in the regulation of spirochete-induced inflammatory responses and the subsequent immune responses. Recent evidence suggests that T cells with pathogenic potential contribute to chronic inflammation at the late stage of Lyme disease. Therefore, the use of therapeutic agents that block chemokine activity might be useful in treating chronic Lyme arthritis.

Borrelia burgdorferi Group↗
PubMed1998

Role of CR4 in Mycobacterium tuberculosis-human macrophages binding and signal transduction in the absence of serum.

The beta2 integrin CR4 is involved in Mycobacterium tuberculosis phagocytosis by human mononuclear phagocytes through the opsonin C3bi. In this study, we demonstrate that M. tuberculosis can bind directly to monocyte-derived macrophages via CR4 in the absence of any opsonins. CR4-transfected CHO cells gave similar results, suggesting recognition by CR4 of bacterial structure. Furthermore, binding of M. tuberculosis transduced a potent signal, resulting in tyrosine phosphorylation of macrophage proteins, which was in part mediated by CR4.

Animals↗
PubMed1982

Adsorption kinetics of laterally and polarly flagellated Vibrio.

The adsorption of laterally and polarly flagellated bacteria to chitin was measured, and from the data obtained, a modified Langmuir adsorption isotherm was derived. Results indicated that the adsorption of laterally flagellated Vibrio parahaemolyticus follows the Langmuir adsorption isotherm, a type of adsorption referred to as surface saturation kinetics, when conditions are favorable for the production of lateral flagella. When conditions were not favorable for the production of lateral flagella, bacterial adsorption did not follow the Langmuir adsorption isotherm; instead, proportional adsorption kinetics were observed. The adsorption of some polarly flagellated bacteria exhibited surface saturation kinetics. However, the binding index (the product of the number of binding sites and bacterial affinity to the surface) of polarly flagellated bacteria differed significantly from that of laterally flagellated bacteria, suggesting that polarly flagellated bacteria adsorb to chitin by a different mechanism from that used by the laterally flagellated bacteria. From the results of dual-label adsorption competition experiments, in which polarly flagellated V. cholerae competed with increasing concentrations of laterally flagellated V. parahaemolyticus, it was observed that laterally flagellated bacteria inhibited the adsorption of polarly flagellated bacteria. In contrast, polarly flagellated bacteria enhanced the adsorption of V. cholerae. In competition experiments, where V. parahaemolyticus competed against increasing concentrations of other bacteria, polarly flagellated bacteria enhanced V. parahaemolyticus adsorption significantly, whereas laterally flagellated bacteria only slightly enhanced the process. The direct correlation observed between surface saturation kinetics, the production of lateral flagella, and the ability of laterally flagellated bacteria to inhibit the adsorption of polarly flagellated bacteria suggests that lateral flagella represent a component of bacterial structure that is important in the adsorption of laterally flagellated bacteria to surfaces. A model for adsorption events of laterally flagellated bacteria is proposed, based on the evidence presented.

Adsorption↗
PubMed1974

Transcriptional regulation of T4 bacteriophage-specific enzymes synthesized in vitro.

In contrast to dihydrofolate reductase and four other phage-specific enzymes, the initiation of deoxynucleotide kinase is essentially prevented if rifampin is added to a culture of Escherichia coli B cells within 1.5 min after infection with T4. Deoxynucleotide kinase thus belongs to a group of so-called delayed-early enzymes that is not initiated from an immediate-early promoter site. We prepared crude extracts from infected cells in a manner designed to maintain the integrity of the complexes of native, endogenous T4 DNA with bacterial structural and enzymatic units concerned with RNA synthesis. The initiation of the synthesis of the mRNA for dihydrofolate reductase, an example of an immediate-early enzyme, and deoxynucleotide kinase, a special type of delayed-early enzyme, was studied with these extracts prepared from cells infected in the absence or presence of chloramphenicol. Initiation of transcription of the dihydrofolate reductase gene is immediate when programmed by extracts made either from cells treated with chloramphenicol prior to infection (CM extracts) or from cells 3 min into the normal infection cycle (3-min extracts). However, initiation of transcription of the deoxynucleotide kinase gene programmed by CM extracts is delayed 2 min relative to the immediate initiation of transcription of the deoxynucleotide kinase gene programmed by 3-min extracts. These experiments duplicated in vitro effects of the antibiotics on the synthesis of phage-specific mRNA previously noted only in vivo.

Carbon Radioisotopes↗
PubMed1987

Direct modulation of human neutrophil adherence by coaggregating periodontopathic bacteria.

Direct interaction between Fusobacterium nucleatum and PMNs produced consistent enhancement of PMN adherence. In contrast, consistent suppression of PMN adherence was observed after direct interactions between PMNs and Bacteroides gingivalis or Actinomyces viscosus. The modulatory effects of these periodontopathic bacteria on PMN function could be seen as early as 2 min after interaction. The effects were abrogated by alterations of bacterial structural integrity with heat, formalin or ultrasonic disruption. Carbohydrate or glycoprotein receptors on PMNs may be involved because the effects were blocked by monosaccharides in the medium. Coaggregation experiments showed that permutations involving F. nucleatum always resulted in enhancement of PMN adherence, and that this can be blocked by D-galactose. These findings may have implications in the initiation and sustenance of chronic inflammatory tissue damage in periodontitis.

Actinomyces↗
PubMed2001

A model combining cell physiology and population genetics to explain Escherichia coli laboratory evolution.

BACKGROUND: Laboratory experiments under controlled conditions during thousands of generations are useful tools to assess the processes underlying bacterial evolution. As a result of these experiments, the way in which the traits change in time is obtained. Under these conditions, the bacteria E. coli shows a parallel increase in cell volume and fitness. RESULTS: To explain this pattern it is required to consider organismic and population contributions. For this purpose we incorporate relevant information concerning bacterial structure, composition and transformations in a minimal modular model. In the short time scale, the model reproduces the physiological responses of the traits to changes in nutrient concentration. The decay of unused catabolic functions, found experimentally, is introduced in the model using simple population genetics. The resulting curves representing the evolution of volume and fitness in time are in good agreement with those obtained experimentally. CONCLUSIONS: This study draws attention on physiology when studying evolution. Moreover, minimal modular models appear to be an adequate strategy to unite these barely related disciplines of biology.

Cell Cycle↗
PubMed2006

Triggering receptor expressed on myeloid cells-1 (TREM-1) amplifies the signals induced by the NACHT-LRR (NLR) pattern recognition receptors.

Triggering receptor expressed on myeloid cells-1 (TREM-1) is a member of a new family of myeloid receptors, encoded by a gene cluster linked to the MHC. Engagement of TREM-1 stimulates intracellular signals, resulting in activation of phagocytosis, neutrophil degranulation, and amplification of cytokine production induced by TLRs. In the present study, a novel property following engagement of TREM-1 is described, namely the amplification of cytokine production induced by the second major class of pattern recognition receptors, the NAIP, CIITA, HET-E, TP-1-leucine-rich repeat (NACHT-LRR; NLR) receptors, which recognize intracellular microorganisms through sensing their muropeptide components of peptidoglycan. The TREM-1/NLR synergism was observed for the production of TNF-alpha, IL-1beta, and IL-6, leading to an increase in cytokine production up to tenfold greater than the additive value of TREM-1 or muropeptide stimulation alone. Several putative mechanisms are proposed to be involved in the synergism between NLRs and TREM-1, including the increase in TREM-1 expression by NLR ligands, and of the expression of nucleotide oligomerization domain-2 receptor by TREM-1 engagement. In contrast, although caspase-1 modulates IL-1beta and IL-6 production after stimulation with anti-TREM-1 antibodies or NLR ligands, it does not appear to be responsible for the synergism between these two pathways. These findings demonstrate that TREM-1 acts on both major recognition pathways of bacterial structures: the extracellular TLR receptors, and the intracellular NLR molecules. This latter finding supports the concept that TREM-1 provides optimal amplification of cytokine-induced inflammation during the initiation of host defense.

Caspase 1↗
PubMed1978

Chronic pyelonephritis. An electron microscopic study in nonhuman primates.

The rhesus monkey (Macaca mulatta) proved to be a successful model for the ultrastructural study of ascending nonobstructive pyelonephritis. The most severe kidney damage occurred where the inflammatory response was greatest, and these areas overlaid a dilated or clubbed calyx. The most prominent ultrastructural changes were in the renal tubular cells that showed swollen mitochondria with ruptured inner membranes, dilated endoplasmic reticulum, and flocculent and irregular basal laminae. No recognizable bacterial structures were seen.

Animals↗
PubMed2000

[Ultrastructural observation of E. coli K12 treated with antibacterial peptide CM4].

The effect of antibacterial peptide CM4 of Bombyx mori against E. coli K12 was investigated using scanning electron microscopy(SEM) and transmission electron microscopy (TEM). The ultrastructural changes of E. coli K12 were observed by the challenge of the purified antibacterial peptide CM4. The results showed that the antibacterial peptide caused a series of pathological changes on E. coli. SEM and TEM revealed aggregates of bacteria and SEM revealed wrinkled bacterial surfaces in the early stage. Thereafter, plasmolysis was observed with irregular holes appearing in the two ends of bacteria and the cytoplasmic contents of the cells leaking out. Finally, bacteria became empty vesicles and disintegrated into small fragments subsequently. Comparatively, the bacterial membrane was normal and the bacterial structure remained intact in the control group.

Animals↗
PubMed2004

Human skin preserved in anhydric sodium chloride for months can be successfully transplanted.

Human skin can be preserved in pulverized sodium chloride dehydrated at 240C for 2 hours at room temperature for periods of weeks or months and successfully transplanted to scid mouse, retaining its normal morphological structure. Fragment of skin of a size of 10 x 10 x 6 mm were harvested during elective vascular and orthopaedic surgery of lower limbs, dried of blood and placed in anhydric sodium chloride powder in tight sealed containers. Prior to transplantation to scid mice, the specimens were desalinated and rehydrated. Specimes preserved for 1 to 6 months and harvested 3-4 weeks after transplantation revealed intensive incorporation of bromdeoxyuridine (BrdU) into basal keratinocytes. They expressed p63 and CD29 (stem cells, and transient cells antigens), PCNA (proliferating cell nuclear antigen) and cytokeratin 16 specific for proliferating keratinocytes. Dermal fibroblasts and few large HLA II cells showed a normal structure. Bacterial flora of skin did not change after grafting. We conclude that human skin can survive in a dehydrated state in sodium chloride for months and after transplantation the epidermal basal layer cells give rise to keratinocyte progenies. Skin fibroblasts and some resident immune cells can also survive.

Anhydrides↗
PubMed1987

T15 group A streptococcal Fc receptor binds to the same location on IgG as staphylococcal protein A and IgG rheumatoid factors.

Previous work has shown that IgG rheumatoid factors (RF) bind to the C gamma 2-C gamma 3 interface region of human IgG in the same area that binds staphylococcal protein A (SPA). Group A, C, and G strains of Streptococci possess Fc receptors that bind to IgG but not to fragments containing only the C gamma 2 or C gamma 3 domains. This work describes the binding site location on human IgG for the binding of the isolated Fc receptor from the T15 strain of a Group A streptococcus and its relationship to the site that binds SPA and the IgG RF. The isolated T15 Fc receptor (T15) with a molecular mass of 29.5 kD inhibited the binding of IgG RF to IgG. The binding of T15 itself to IgG was strongly inhibited by SPA (42.0 kD) and its monovalent fragment D (7 kD). Human IgG fragments consisting of the C gamma 3 domains did not inhibit the binding of T15 to IgG, whereas those with both domains were effective inhibitors. T15 did not bind to rabbit IgG fragments consisting of either the C gamma 2 or C gamma 3 domains, but did bind to those with both domains. An IgG3 myeloma protein was a poor inhibitor and has been shown to bind poorly to the IgG RF. Most IgG3 myeloma proteins did not bind to SPA. The substitution of Arg and Phe for His 435 and Tyr 436 is responsible for the poor binding of IgG3 to SPA and to the IgG RF. Chemical modification of His or Tyr on IgG reduced its ability to inhibit the binding of T15 to IgG. Reversal of the chemical modifications with hydroxylamine resulted in near complete restoration of inhibitory capacity. This information, collectively, coupled with the known positions in space of the His and Tyr residues in the C gamma 2-C gamma 3 interface region, verified that both His 435 and Tyr 436, and possibly His 310 and 433, are involved. These residues are also involved in binding SPA and the IgG RF. These data therefore indicate that the T15 Group A Streptococcal Fc receptor binds to the same location on the Fc of IgG as SPA and the IgG RF. The biologic relevance of these similarities between bacterial cell wall Fc receptors and IgG RF are not yet apparent, but suggest that RF could bear the internal image of these bacterial structures.

Animals↗