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Biomedical subjects

A Cerami

Publications and source records attributed to A Cerami.

At least 163 records · Page 9Linked to original sources
PubMed1989

Tumour necrosis factor production in Falciparum malaria and its association with schizont rupture.

To investigate the involvement of tumour necrosis factor (TNF) in human malaria, we studied TNF production in patients infected with Plasmodium falciparum, and in co-cultures of human mononuclear cells and malaria parasites in vitro. In the examined sample, plasma TNF levels of over 39 pg/ml were detected in the plasma of 59% of Gambian children with acute malaria, 17% of convalescents, 9% of children with mild infections other than malaria, and 7% of healthy Gambian adults. Mononuclear cells of acute malaria patients, when stimulated with endotoxin in vitro, secreted twice as much TNF as did those of convalescent individuals, and three times that of healthy adult controls. Erythrocytic cultures of P. falciparum stimulated increased TNF secretion by mononuclear cells from uninfected individuals, and a sharp rise in the rate of secretion occurred shortly after schizont rupture. We suggest that malaria fever is mediated, at least in part, through paroxysmal TNF release associated with schizont rupture.

Animals↗
PubMed1989

Endogenous cachectin/tumour necrosis factor-alpha production contributes to experimental cancer-associated cachexia.

Several lines of investigation suggest that the endogenous synthesis of cachectin contributes to the host changes that occur in cancer. Although serum appearance of cachectin in tumour-bearing animals and patients with cancer cannot be measured with current techniques, there is accumulating evidence to suggest that tissue macrophage production of cachectin is accelerated in organisms with tumours. Production of cachectin, coupled with the simultaneous synthesis of other cytokines that act synergistically with cachectin may explain many of the host changes in the absence of detectable circulating levels.

Cachexia↗
PubMed1989

Nonenzymatic glycosylation of DNA by reducing sugars.

The process of nonenzymatic glycosylation has proven to be not only of interest to food chemists in the preservation of foodstuffs, but has become of increasing interest to biologists. The nonenzymatic glycosylation of biologically relevant proteins has become an important factor in explaining some of the posttranslational modifications of proteins observed in diabetes and aging. Using in vitro and in vivo models, we describe in this paper the implications that the nonenzymatic glycosylation of DNA may have in the biological aging process.

DNA↗
PubMed1988

Resolution of the two components of macrophage inflammatory protein 1, and cloning and characterization of one of those components, macrophage inflammatory protein 1 beta.

A number of macrophage-derived mediators have been implicated in the vascular changes of inflammation. We recently reported the isolation of a novel monokine, macrophage inflammatory protein 1 (MIP-1), which causes local inflammatory responses in vivo, and induces superoxide production by neutrophils in vitro. Purified native MIP-1 comprises two peptides with very similar physical characteristics. We report here the resolution of MIP-1 into component peptides by SDS-hydroxylapatite chromatography, and compare the NH2-terminal sequences of the two peptides, now referred to as MIP-1 alpha and MIP-1 beta. A synthetic oligonucleotide probe pool corresponding to the NH2-terminal amino acid sequence of MIP-1 beta was used to isolate a cDNA clone containing its coding sequence. The sequence codes for a 109 amino acid-long polypeptide, of which 69 amino acids correspond to the mature product. Comparison of this MIP-1 beta cDNA with our previously cloned MIP-1 alpha sequence reveals that the MIP-1 peptides, members of a growing family of potential inflammatory mediators, are distinct but highly homologous (58.9% sequence identity) products of different genes.

Animals↗
PubMed1988

Detection of circulating tumor necrosis factor after endotoxin administration.

Cytokines, products of stimulated macrophages, are thought to mediate many host responses to bacterial infection, but increased circulating cytokine concentrations have not been detected consistently in infected patients. We measured plasma concentrations of circulating tumor necrosis factor alpha (cachectin), interleukin-1 beta, and gamma interferon, together with physiologic and hormonal responses, in 13 healthy men after intravenous administration of Escherichia coli endotoxin (4 ng per kilogram of body weight) and during a control period of saline administration. Eight additional subjects received ibuprofen before receiving endotoxin or saline. Plasma levels of tumor necrosis factor were generally less than 35 pg per milliliter throughout the control period, but increased 90 to 180 minutes after endotoxin administration to mean peak concentrations of 240 +/- 70 pg per milliliter, as compared with 35 +/- 5 pg per milliliter after saline administration. Host responses were temporally associated with the increase in circulating tumor necrosis factor at 90 minutes, and the extent of symptoms, changes in white-cell count, and production of ACTH were temporally related to the peak concentration of tumor necrosis factor. Ibuprofen pretreatment did not prevent the rise in circulating tumor necrosis factor (mean peak plasma level, 170 +/- 70 pg per milliliter) but greatly attenuated the symptoms and other responses after endotoxin administration. Concentrations of circulating interleukin-1 beta and gamma interferon did not change after endotoxin administration. We conclude that the response to endotoxin is associated with a brief pulse of circulating tumor necrosis factor and that the resultant responses are effected through the cyclooxygenase pathway.

Adrenocorticotropic Hormone↗
PubMed1988

Cloning and characterization of a cDNA for murine macrophage inflammatory protein (MIP), a novel monokine with inflammatory and chemokinetic properties.

In the course of studies on cachectin/TNF being conducted in our laboratory, a novel macrophage product has been detected and characterized. Termed macrophage inflammatory protein or MIP, this protein appears to be an endogenous mediator of the inflammatory events induced by endotoxin. A cDNA cloned probe for this protein has been isolated from a lambda gt10 phage library prepared from poly(A)+ RNA obtained of endotoxin-induced RAW264.7 cells. The sequence codes for a 92 amino acid-long polypeptide, of which 69 amino acids correspond to the mature product. The sequence predicts a molecular weight of 7,889 and structural analysis of the protein indicates a characteristic signal sequence alpha-helix and a hydrophobic core. Sequence data also confirm no sequence similarity to any other protein listed in the Dayhoff data base.

Amino Acid Sequence↗
PubMed1988

Tumor necrosis factor alpha/cachectin is a growth factor for thymocytes. Synergistic interactions with other cytokines.

Recombinant murine (rm) TNF-alpha but not recombinant human (rh) TNF-alpha induces the proliferation of murine thymocytes in the presence of a comitogenic stimulus. This effect does not appear to be due to the production of significant levels of IL-1, IL-2, or IL-4. although not directly mitogenic (i.e., in the absence of PHA-P) for thymocytes, rmTNF-alpha amplifies the direct mitogenic signals from hIL-1 and rhIL-2 but not rmIL-4. In the presence of PHA-P, thymocytes stimulated with hIL-1, rhIL-2, and rmIL-4 produced significant amounts of TNF-alpha. Although rhTNF-alpha does not induce a proliferative response, it will competitively inhibit the proliferative response of thymocytes to rmTNF-alpha. These data suggest a critical role for TNF-alpha in the intrathymic proliferation of developing T cells.

Animals↗
PubMed1988

Cachectin/tumor necrosis factor induces cachexia, anemia, and inflammation.

Cachexia is a potentially lethal syndrome of unknown etiology characterized by anorexia, weight loss, and protein wasting that frequently complicates the treatment of chronic inflammation and cancer. Cachectin/TNF was isolated during the search for a humoral mediator of cachexia and found to stimulate the breakdown of energy stores from adipocytes and myocytes in vitro, but the chronic effects of the monokine in vivo are not known. Sublethal doses of recombinant human cachectin administered twice daily for 7-10 d caused cachexia in rats, as evidenced by reduced food intake, weight loss, and depletion of whole-body lipid and protein stores. Significant anemia is also observed and found to be the result of decreased red blood cell mass, not expanded plasma volume. Leukocytosis and histopathological evidence of tissue injury and inflammation are observed in several organs, including omentum, liver, spleen, and heart. These data suggests that the exposure of the normal host to cachectin is capable of inducing a pathophysiological syndrome of cachexia, anemia, and inflammation similar to that observed during inflammatory states or malignancy.

Anemia↗
PubMed1988

Macrophages secrete a novel heparin-binding protein with inflammatory and neutrophil chemokinetic properties.

We report the identification and purification of a new inflammatory monokine synthesized by the macrophage tumor cell line RAW 264.7 in response to endotoxin. This monokine, which we term "macrophage inflammatory protein" (MIP), is a doublet with an apparent molecular mass of approximately 8,000 daltons on SDS-PAGE but forms aggregates of greater than 2 x 10(6) daltons as assessed by gel filtration. Partial NH2-terminal amino acid sequence data reveal no significant homology with any previously described protein. Although the monokine is anionic under physiological conditions, it is one of two major macrophage-secreted proteins that bind to heparin at high salt concentrations. At 100 ng/ml or greater, MIP is chemokinetic for human polymorphonuclear cells and triggers hydrogen peroxide production. Subcutaneous injection of 10 ng or greater of MIP into footpads of C3H/HeJ mice elicits an inflammatory response, characterized by neutrophil infiltration. These findings suggest that MIP is an endogenous mediator that may play a role in the host responses that occur during endotoxemia and other inflammatory events.

Amino Acid Sequence↗
PubMed1988

Cachectin/TNF production in experimental burns and Pseudomonas infection.

Burn injury and infection result in significant losses of lean tissue. The cytokine cachectin/tumor necrosis factor has been implicated in this process but is not uniformly detected during infection. We sought to determine the relationship between body composition changes and in vivo hepatic levels of pretranslational message for cachectin (messenger RNA) in a burn and infection rodent model. Adult Wistar rats were grouped as follows: (1) freely fed, (2) 30% burn, (3) 30% burn with Pseudomonas aeruginosa infection, (4) pair fed, and (5) 30% burn and infection with recombinant cachectin. Compared with controls or animals only burned, burned and infected rats had a 100% increase in hepatic cachectin messenger RNA content, lost carcass protein, and exhibited muscle loss with sparing of liver mass. Tissue production of cachectin as well as other cytokines may be sufficient to mediate several body composition changes observed in response to injury and infection.

Animals↗
PubMed1988

Characterization of a solubilized cell surface binding protein on macrophages specific for proteins modified nonenzymatically by advanced glycosylated end products.

Glucose can react nonenzymatically with free protein amino groups to form Amadori products, 1-amino-1-deoxyketose residues. These adducts can undergo subsequent rearrangements and dehydrations to form a complex group of brown, fluorescent pigments collectively referred to as advanced glycosylation end products (AGE). One AGE has been identified as 2-(2-furoyl)-4(5)-(2-furanyl)-1H-imidazole (FFI). The AGE-protein adducts accumulate with time and are implicated in irreversible tissue damage. We have previously demonstrated that macrophages bind and degrade AGE-proteins via a specific cell surface binding protein, thus selectively removing senescent macromolecules. In the present communication, we have solubilized this binding protein from the membranes of the murine macrophage cell line RAW 264.7. We have characterized the nature of binding protein-ligand interaction by competition studies using modified ligands. The data indicate that the carbonyl group, the furan ring(s), and the central imidazole structure are all important in the binding protein-ligand interaction. We have established that the binding constant (Ka) of binding protein for the ligand FFI-BA is 3.1 X 10(7) M-1. Chemical crosslinking studies have demonstrated that the molecular weight of the binding protein is 90,000.

Animals↗
PubMed1988

"Subversive" substrates for the enzyme trypanothione disulfide reductase: alternative approach to chemotherapy of Chagas disease.

The trypanosomatid flavoprotein disulfide reductase, trypanothione reductase, is shown to catalyze one-electron reduction of suitably substituted naphthoquinone and nitrofuran derivatives. A number of such compounds have been chemically synthesized, and a structure-activity relationship has been established; the enzyme is most active with compounds that contain basic functional groups in side-chain residues. The reduced products are readily reoxidized by molecular oxygen and thus undergo classical enzyme-catalyzed redox cycling. In addition to their ability to act as substrates for trypanothione reductase, the compounds are also shown to effectively inhibit enzymatic reduction of the enzyme's physiological substrate, trypanothione disulfide. Under aerobic conditions, trypanothione reductase is not inactivated by these redox-cycling substrates, whereas under anaerobic conditions the nitrofuran compounds cause irreversible inactivation of the enzyme. When tested for biological activity against Trypanosoma cruzi trypomastigotes, many of the test compounds were trypanocidal, and this activity correlated with their relative ability to act as substrates for trypanothione reductase. The activity of the enzyme with these redox-cycling derivatives constitutes a subversion of its normal antioxidant role within the cell. For this reason these compounds may be termed "subversive" substrates for trypanothione reductase.

Aerobiosis↗