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Query: UMLS:C0032285 (pneumonia)
 54,520 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two types of tumor necrosis factor membrane receptors (TNF-R) have been identified, namely 55 and 75 kDa TNF-R. Soluble forms of these receptors are present in the human serum. Recent findings on the role of these two TNF-R in biological cell signaling and the clinical significance of the serum levels of soluble TNF-R (sTNF-R) were reviewed. It is not the uptake of TNF molecules into cells but rather the molecular capping of TNF-R on the cell membrane that initiates the biological activity of TNF. The 55 kDa TNF-R mediates major bioactivities of TNF, while the significance of 75 kDa TNF-R remains unclear. We herein suggest a new concept of the role of these two TNF-R: The 75 kDa TNF-R signal appeared to enhance that of 55 kDa TNF-R in the induction of ICAM-1 expression on HL-60 human promyelocytic leukemic cells. High serum levels of sTNF-R are reported in patients with malignancy, endotoxin shock, pneumonia, and autoimmune diseases. However, the source of elevated serum sTNF-R remains unclear. Studies on the clinical usefulness of serum sTNF-R levels as cancer and inflammation markers are now being carried out.
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PMID:The role of tumor necrosis factor receptors in cell signaling and the significance of soluble form levels in the serum. 800 60

Two distinct types of tumor necrosis factor receptors (TNF-R) have been identified (TNF-R55 and TNF-R75). Both TNF-R also exist in soluble forms (TNF-sR), resulting from the release of the extracellular domains (TNF-sR55 and TNF-sR75). TNF-sR may play an important role in vivo as they can bind to TNF alpha and prevent ligand binding to the cellular TNF-R, thus acting as naturally occurring inhibitors of TNF alpha. Sera from lung allograft recipients with cytomegalovirus (CMV) pneumonitis (12 patients) were assayed for TNF-sR55 and TNF-sR75. The concentrations were compared with those from either control lung recipients displaying neither rejection nor infection (12 patients), or lung recipients with allograft rejection (12 patients). Serum TNF-sR55 and TNF-sR75 concentrations were measured by enzyme-linked immunologic binding assay. Serum TNF-sR55 and TNF-sR75 concentrations were significantly higher during CMV pneumonitis (mean +/- SEM: 13.7 +/- 4.7 ng/ml, and 11.7 +/- 2.7 ng/ml, respectively) than during allograft rejection (3.7 +/- 0.3 ng/ml, p < 0.001, and 2.6 +/- 0.6 ng/ml, p < 0.001, respectively). They were also higher than in control subjects (3.6 +/- 0.3 ng/ml, p < 0.001, and 1.9 +/- 0.5 ng/ml, p < 0.001, respectively). Serum TNF alpha concentration was low in case of rejection or in control subjects (< 20 pg/ml). Conversely increased levels of TNF alpha were detected in the serum of six out of the 12 patients with CMV pneumonitis (p < 0.03 versus rejection and control subjects). Ganciclovir treatment of CMV pneumonitis led to a dramatic decrease of TNF alpha, TNF-sR55, and TNF-sR75 serum levels.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Soluble TNF receptors (TNF-sR55 and TNF-sR75) in lung allograft recipients displaying cytomegalovirus pneumonitis. 800 30

These studies have direct clinical relevance to the multisystem deficits seen in mechanical biliary obstruction (Fig. 3). Defects in two crucial elements of effective phagocytosis (chemotaxis and intracellular killing) have been demonstrated in obstructive jaundice. At the same time, complete diversion of bile (containing bile salts and s-IgA) from the gut lumen causes changes in the endogenous bacterial flora, loss of mucosal integrity, and decreased endotoxin inactivation, resulting in portal bacteremia, endotoxemia, and increased translocation to mesenteric lymph nodes. This increased load comes at a time when the liver is metabolically impaired and RES function is abnormal. Decreased hepatic clearance of intrabiliary bacteria may contribute to the development of cholangitis (by both ascending and hematogenous routes). Inadequate RES control of portal bacteremia results in "spillover" with subsequent systemic bacteremia and localization of organisms in the lungs where they may contribute to pulmonary dysfunction or pneumonia. Although reversal of jaundice is readily accomplished by either external or internal biliary drainage, chronic biliary obstruction results in functional alterations in the liver which are reversed, generally incompletely, only after weeks or months of decompression. External biliary decompression fails to restore the enterohepatic circulation, preventing bile salts, s-IgA, and other substances from entering the lumen of the gut. It is not as effective as internal biliary drainage in reversing RES dysfunction or restoring immune parameters. Even with internal drainage, restoration of normal function in these systems takes weeks or months. Muramyl dipeptide analogues show some promise. A possible unifying mechanism may provide the clues to further experiments which will suggest better ways of reducing the morbidity and mortality in these patients. All macrophages share common functions which include not only phagocytosis but also antigen processing and the production of cytokines. The immune dysfunction noted in obstructive jaundice may be due to inadequate or inappropriate antigen processing or cytokine production by macrophages or to abnormal hepatocyte-Kupffer cell interactions. Kupffer cells are the largest pool of macrophages. Most numerous in periportal areas, Kupffer cells process significant quantities of enteric-derived antigens and Kupffer cell blockade results in an exaggerated response to these antigens. Kupffer cells also act as important scavengers of endotoxin, which stimulates the release of TNF and IL-6.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:The pathophysiology of biliary obstruction and its effect on phagocytic and immune function. 802 41

We recently reported that diffuse aspiration bronchiolitis (DAB) was detected in 1% of autopsied lungs of aged cases of pneumonia. We hypothesized whether repeated HCl micro-aspiration (RHMA) is involved in DAB and established an animal model by administering HCl intratracheally to rats every two days for 2 weeks. Saline was given to control animals in the same fashion. Then, we performed bronchio-alveolar lavage (BAL) or excised lungs for histologic examination. There was no difference in BAL cell counts, TNF alpha-production, elastase-like activity or albumin levels between the HCl and control groups. Histologically, DAB-like findings were observed in the HCl-treated animals. These data suggest that RHMA might be involved in DAB, while neither TNF alpha-production nor elastase-like activity may play a significant role in inducing DAB.
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PMID:[Diffuse aspiration bronchiolitis (DAB) produced in animals by repeated HCl microaspiration]. 807 7

To gain further insight into the pathogenesis of the adult respiratory distress syndrome (ARDS), the authors studied possible relationships among the activation status of circulating polymorphonuclear neutrophils (PMN), cytokine levels, and the severity of lung injury in 31 patients: 15 with ARDS, 9 with severe pneumonia uncomplicated by ARDS, and 7 mechanically ventilated patients with neither ARDS nor pneumonia. Nine healthy subjects served as controls. Using flow cytometry, the authors identified a subpopulation of PMN with an increased capacity to generate hydrogen peroxide after stimulation ex vivo in all three patient groups; significantly higher values were found in those with ARDS. The PMN stimulation index, a reflection of the degree of hyperresponsiveness, correlated with elevated levels of tumor necrosis factor alpha (TNF-alpha) in plasma, and both spontaneous and lipopolysaccharide (LPS)-induced TNF-alpha production by cultured monocytes. These biological expressions of PMN activation and cytokine generation both correlated with indices of the severity of lung injury, but not with the overall clinical severity. In contrast, IL-6 and IL-1 beta showed little or no relationship with either the degree of lung injury or PMN hyperresponsiveness. We conclude that TNF alpha-primed PMN may play a major role in the pathogenesis of ARDS-associated lung injury.
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PMID:[State of activation of polynuclear neutrophils and cytokines in acute respiratory distress syndrome in adults]. 830 26

The role of tumor necrosis factor alpha (TNF alpha) in the pathogenesis of influenza A viral pneumonia was examined. CD-1 male mice were challenged intranasally with influenza A virus A/PR/8/34 (H1N1) and administered rabbit anti-mouse TNF alpha-specific-neutralizing antibodies intraperitoneally. The effect of treatment on virus titer, TNF alpha levels, morbidity, mortality, and on pathologic lung lesions were compared with sham-treated controls. The severity of gross and histologic lung lesions positively correlated with the peak bronchoalveolar TNF alpha levels and was ameliorated with anti-TNF alpha treatment. Survivorship was prolonged in mice given a lethal dose of virus by treatment with TNF-alpha neutralizing antibodies. Reduction of TNF alpha levels by treatment with TNF alpha-antibodies did not affect virus titers in the lung. These results suggest that TNF alpha is a mediator of pulmonary inflammation during influenza A viral pneumonia, but may not play a significant anti-viral role in influenza pneumonia.
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PMID:Tumor necrosis factor as a mediator of inflammation in influenza A viral pneumonia. 855 46

Despite improvements in immunosuppression, rejection occurs in 50% of liver transplant patients and may cause significant morbidity. The most frequent cause of death after liver transplantation is severe infection. Determination of the cytokine network may lead to earlier detection of patients at risk for severe rejection and infection. For this purpose, 81 patients with 85 liver transplants were monitored for cytokines and neopterin on a daily basis. During the first postoperative month, 28 patients (34.6%) developed acute rejection; 14 patients were successfully treated with methylprednisolone (steroid-sensitive rejection), while 14 patients required additional treatment with FK506 and OKT3 (steroid-resistant rejection). Ten patients developed severe infections, and 11 patients experienced asymptomatic cholangitis. Patients with an uneventful postoperative course (n=37) were the control group. One-year patient survival was 88.9%: 1 patient died because of chronic rejection and Pseudomonas urosepsis; a further 4 patients died of aspergillus pneumonia and bacterial sepsis. Soluble TNF-RII, sIL-2R-, and IL-10 levels were significantly elevated 3 days prior to or at the onset of acute steroid-resistant rejection (P < or = 0.01 versus steroid-sensitive rejection and on uneventful postoperative course). An increase in IL-8, neopterin, and sTNF-RII was indicative of severe infection 3 days prior to onset of infection. In this group of patients, a simultaneous increase in IL-10 indicated a lethal outcome of severe infection. During the second week of acute steroid-resistant rejection and lethal infection, a significant rise in IL-1beta, IFN-gamma, and IL-6 was observed (P < or = 0.01 versus control groups). The different patterns in neopterin- and cytokine-increase could differentiate between severe rejection and severe infection. Furthermore, the increase in these parameters indicated severe rejection--i.e., steroid resistance at the onset of acute rejection--which could prompt us to initiate rescue therapy immediately. The ability to detect patients at risk for severe or lethal infection may result in intensified infectious screening and more aggressive antiinfectious treatment. Therefore, routine monitoring of these parameters may lead to changes in therapeutic management of severe acute rejection and infection after liver transplantation.
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PMID:Cytokine pattern during rejection and infection after liver transplantation--improvements in postoperative monitoring? 895 70

Pneumocystis carinii pneumonia remains a serious complication of immunodeficiency. Vitronectin (VN) and fibronectin (FN) accumulate in the lung during P. carinii infection and bind to the organism, thereby enhancing macrophage release of TNF alpha. It is not known whether VN and FN also regulate uptake and degradation of P. carinii by macrophage when present in concentrations similar to those in the lung during pneumonia. To address this, macrophages were cultured with 35S-radiolabeled P. carinii and organism binding, phagocytosis, and degradation determined in media alone (control), or in the presence of VN or FN (100 micrograms/ml each). Soluble VN and FN, in concentrations similar to those in the host, did not significantly affect binding uptake or degradation of P. carinii by alveolar macrophages. Thus, although VN and FN enhance macrophage activation during P. carinii pneumonia, phagocytosis of the organism is not increased by these host glycoproteins under steady-state conditions.
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PMID:Steady-state effects of vitronectin and fibronectin on the binding, uptake, and degradation of Pneumocystis carinii in rat alveolar macrophages. 924 75

In order to explore the allelic polymorphism of HLA-DR and TNF B loci and susceptibility to systemic lupus erythematosus (SLE) in the Han nationality of northern China with the aid of methods of polymerase chain reaction/sequence specific primers (PCR/SSP) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) respectively. The findings from a case-control study on 151 blood samples (45 from the cases and 106 from the controls) indicated that there were significantly higher frequency of DR2 (P < 0.05, RR = 1.56) and DR3 (P < 0.01, RR = 2.69), which represent candidate susceptible genes or useful markers for SLE. The DR5 allele in the samples (P < 0.05, RR = 0.43) might be an antagonistic or protective allele, or a marker for such allele. The frequency of TNF B * 1 and TNF B * 2 alleles was investigated in 45 SLE patients and 80 healthy controls and it was found that the frequency of TNF B * 2 allele was significantly higher in the patient group (P < 0.05, RR = 1.84). It might also be a suspicious susceptible allele or a marker for such allele. The frequency of HLA polymorphisms in various clinical/immunological subsets of our patient population was also determined. Clinical findings used include plasma SC5b-9 level, SSA, SSB, Sm, RNP, ANA antibodies, and SLE complications (SLE nephritis, pneumonia & encephalopathy). It turned out that there was a positive association between HLA-DR2 allele and SLE nephritis (P < 0.05, RR = 1.32).
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PMID:[Study on some susceptible genes of systemic lupus erythematosus in Han nationality of China]. 927 40

A case in which the enterotoxins of Staphylococcus aureus may have served as bacterial superantigens is presented. This 71-year-old man developed proteinuria and renal dysfunction after contacting pneumonia caused by methicillin-resistant Staphylococcus aureus (MRSA), coagulase type II. The infection occurred after surgery for recurrent lung cancer. Staphylococcus enterotoxins B, C, and TSST-1 were detected from the bacillus. Ten days after the onset of pneumonia, proteinuria was noted; urinary protein was as high as 1.8 g/day. The serum creatinine was elevated from 1.0 mg/dl to 3.7 mg/dl. Several immunological reactions were detected; the serum levels of IgG and IgA were increased, and the selective usage of T-cell receptor V beta (TCRV beta) was observed. Serum levels of IL-1 beta, IL-2, IL-6, IL-8, IL-12, and tumor necrosis factor alpha (TNF alpha) were also elevated. Examination of the renal biopsy specimen by light microscopy showed minor to mild mesangial proliferative glomerulonephritis. Immunofluorescence microscopy demonstrated the deposition of IgG, IgA, and C3, mainly along the capillary walls. Electron microscopy revealed electron dense deposits, mainly in the subepithelial areas, and injury to the glomerular basement membrane. When the pneumonia improved following antibiotic therapy, the renal function also improved, and proteinuria decreased. The levels of immunoglobulins and the usage of TCRV beta also decreased. Because staphylococcus enterotoxins act as superantigens, we believe this to be a typical case of superantigen-related glomerulonephritis.
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PMID:A case of superantigen-related glomerulonephritis after methicillin-resistant Staphylococcus aureus (MRSA) infection. 940 16


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