Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Necrosis”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources

Reduced glutathione depletion causes necrosis and sensitization to tumor necrosis factor-alpha-induced apoptosis in cultured mouse hepatocytes.

The effect of reduced glutathione (GSH) depletion by acetaminophen (APAP), diethylmaleate (DEM), or phorone on the mode of cell death and susceptibility to tumor necrosis factor (TNF)-induced cell death was studied in cultured mouse hepatocytes. Dose-dependent necrosis was the exclusive mode of cell death with APAP alone, but the addition of TNF-alpha induced a switch to about half apoptosis without changing total loss of viability. This effect was seen at 1 and 5 mmol/L but was inhibited at 10 and 20 mmol/L APAP. The switch to apoptosis was associated with increased caspase activities, release of cytochrome c, and DNA laddering and was inhibited by caspase inhibitors. DEM and phorone also induced dose-dependent necrosis. Treatment with TNF-alpha under these conditions lead to incremental cell death in the form of apoptosis at 0.25 and 0.5 mmol/L DEM and 0.1 and 0.2 mmol/L phorone. At 1.0 and 2.0 mmol/L DEM and 0.5 mmol/L phorone, 90% to 100% necrosis was observed with resistance to TNF-alpha effects. The apoptosis with TNF-alpha plus DEM was confirmed by DNA laddering and inhibition by caspase inhibitors. However, in the presence of caspase inhibitors, the increment in cell death induced by TNF-alpha persisted as an increase in necrosis. A combination of antioxidants, vitamin E, and butylated hydroxytoluene (BHT) markedly inhibited necrosis induced by APAP or DEM alone, but the sensitization to TNF-alpha-induced apoptosis was unaffected. GSH monoethylester (GSH-EE) protected against necrosis and apoptosis. In conclusion, depletion of GSH by APAP, DEM, or phorone causes oxidative stress-induced necrosis and sensitizes to an oxidative stress independent TNF-alpha-induced apoptosis.

Acetaminophen↗

Cisplatin-treated murine peritoneal macrophages induce apoptosis in L929 cells: role of Fas-Fas ligand and tumor necrosis factor-tumor necrosis factor receptor 1.

Cisplatin [cis-diamminedichloroplatinum (II)]-treated murine peritoneal macrophages interact with L929 cells in vitro in a sequential manner, resulting in the formation of contact between the two cells. This interaction leads to the death of L929 cells by the process of apoptosis. The detailed investigations have suggested the involvement of two different pathways in macrophage-mediated L929 cell apoptosis. It is observed that the induction of apoptosis in L929 cells by cisplatin-treated macrophages is contact dependent and is mediated through Fas-Fas ligand and tumor necrosis factor-tumor necrosis factor receptor 1 pathways. This conclusion was based on the Western blot and immunoprecipitation analysis of Fas-Fas ligand, tumor necrosis factor-tumor necrosis factor receptor 1, Fas-associated death domain and tumor necrosis factor receptor-associated death domain. The Fas-Fas ligand interaction between macrophages and L929 cells increased the expression of Fas-associated death domain, and tumor necrosis factor-tumor necrosis factor receptor 1 interaction between macrophages and L929 cells increased the expression of tumor necrosis factor receptor-associated death domain in L929 cells. The induction of apoptosis in L929 cells was investigated by DNA fragmentation, Annexin V staining and Western blot analysis of Bax, Bcl-2, Bid, cytochrome c, poly(ADP ribose) polymerase, CAD, caspase-8 and caspase-3.

Animals↗

In vitro and in vivo expression of interleukin-1alpha and tumor necrosis factor-alpha mRNA in pemphigus vulgaris: interleukin-1alpha and tumor necrosis factor-alpha are involved in acantholysis.

Keratinocyte-derived cytokines have been implicated in the pathogenesis of a number of skin diseases. In this study we examined the possible role of keratinocyte-derived cytokines in the development of acantholysis in pemphigus vulgaris. Nineteen patients with pemphigus vulgaris, demonstrating the characteristic clinical, pathologic, and immunopathologic findings were studied. In situ immunolabeling demonstrated the presence of two cytokines interleukin-1alpha and tumor necrosis factor-alpha, in lesional and perilesional areas. Results were confirmed by reverse transcriptase-polymerase chain reaction, demonstrating overexpression of both cytokines in vivo. To study the role of these cytokines in the pathogenesis of pemphigus vulgaris both in vitro and in vivo studies were performed. The results of the in vitro study demonstrated that pemphigus vulgaris IgG induced interleukin-1alpha and tumor necrosis factor-alpha mRNA in the skin. The potential pathogenic role of these mediators was demonstrated by a blocking study using antibodies against human interleukin-1alpha and tumor necrosis factor-alpha in keratinocytes cultures. A combination of anti-interleukin-1alpha and anti-tumor necrosis factor-alpha antibodies inhibited in vitro pemphigus vulgaris IgG induced acantholysis. To confirm the role of interleukin-1 and tumor necrosis factor-alpha in pemphigus, we utilized passive transfer studies using interleukin-1 deficient mice (ICE-/-, interleukin-1beta-/-) and tumor necrosis factor-alpha receptor deficient mice (TNFR1R2-/-). Both groups demonstrated a decreased susceptibility to the passive transfer of pemphigus. Our data support the role of cytokines interleukin-1 and tumor necrosis factor-alpha in the pathogenesis of pemphigus vulgaris.

Acantholysis↗

Docosahexaenoic acid enrichment can reduce L929 cell necrosis induced by tumor necrosis factor.

We previously reported that docosahexaenoic acid (DHA) attenuated tumor necrosis factor (TNF)-induced apoptosis in human monocytic U937 cells (J. Nutr. 130: 1095-1101, 2000). In the present study, we examined the effects of DHA and other polyunsaturated fatty acids (PUFA) on TNF-induced necrosis, another mode of cell death, using L929 murine fibrosarcoma cells. After preincubation with PUFA conjugated with BSA for 24 h, cells were treated with TNF or TNF+actinomycin D (Act D). Preincubation of cells with DHA enriched this polyunsaturated acid in the phospholipids and attenuated cell death induced by either TNF or TNF+Act D. When cells were treated with TNF alone, DNA laddering was not detected, and cells were coincidently stained with both annexin V-FITC and propidium iodide, indicating that the death mode was necrotic. TNF+Act D predominantly induced necrosis, although concurrent apoptotic cell death was also observed in this case. Preincubation with oleic acid, linoleic acid or 20:3(n-3) did not affect TNF-induced necrosis. Conversely, supplementation with n-3 docosapentaenoic acid (DPAn-3) or eicosapentaenoic acid (EPA) reduced necrotic cell death, but to a lesser extent in comparison with DHA. Unlike the case of U937 cell apoptosis, arachidonic acid (AA) significantly attenuated L929 cell necrosis, and 20:3(n-6) or 22:4(n-6) showed similar or less activity, respectively. Statistical evaluation indicated that the order of effective PUFA activity was DHA>DPAn-3> or =EPA>AA approximately 20:3(n-6)> or =22:4(n-6). One step desaturation, C2 elongation or C2 cleavage within the n-6 or n-3 fatty acid group was probably very active in L929 cells, because AA, synthesized from 20:3(n-6) or 22:4(n-6), and C22 fatty acids, synthesized from AA or EPA, were preferentially retained in cellular phospholipids. These observations suggested that attenuation of TNF-induced necrosis by the supplementation of various C20 or C22 polyunsaturated fatty acids is mainly attributable to the enrichment of three kinds of polyunsaturated fatty acids, i.e., DHA, DPAn-3 or AA, in phospholipids. Among these fatty acids, DHA was the most effective in the reduction of L929 necrosis as observed in the case of U937 apoptosis. This suggests that DHA-enriched membranes can protect cell against TNF irrespective of death modes and that membranous DHA may abrogate the death signaling common to necrosis and apoptosis.

Animals↗

Lack of association of severe preeclampsia with maternal and fetal mutant alleles for tumor necrosis factor alpha and lymphotoxin alpha genes and plasma tumor necrosis factor alpha levels.

OBJECTIVE: The purpose of this study was to determine whether the increased frequency of mutant alleles of the gene for tumor necrosis factor alpha and elevated maternal and fetal plasma levels of tumor necrosis factor alpha were associated with severe preeclampsia. STUDY DESIGN: We performed a prospective cross-sectional study involving 112 patients with severe preeclampsia matched for gestational age with 106 normotensive pregnant women. Deoxyribonucleic acid for restriction fragment length polymorphism analysis was extracted from maternal and fetal blood. Two mutations associated with the gene for tumor necrosis factor alpha were assayed by polymerase chain reaction. Polymerase chain reaction products were digested with the restriction enzyme Ncol and then fractionated by gel electrophoresis. Genotypic frequencies were calculated. Maternal and fetal plasma tumor necrosis factor alpha levels were assayed by the dual monoclonal antibody sandwich enzyme-linked immunosorbent assay technique. The chi2 test, the Fisher exact test, the Student t test, and the Mann-Whitney test were performed to calculate statistical significance. RESULTS: The differences in the genotypic frequencies of the two loci were not significant in either maternal or fetal samples between control women and women with pregnancies complicated by severe preeclampsia. There was no statistical difference in median maternal plasma levels of tumor necrosis factor alpha between control subjects (0.0 pg/mL) and patients with severe preeclampsia (2.5 pg/mL; P =.36). Unexpectedly, fetal plasma tumor necrosis factor alpha levels were found to be significantly elevated in control women (18.4 pg/mL) relative to women with severe preeclampsia (9.1 pg/mL; P <.0001). CONCLUSION: Neither the genotypic frequencies for tumor necrosis factor alpha mutant alleles nor maternal tumor necrosis factor alpha plasma levels were increased in patients with severe preeclampsia.

Adult↗

Regulation of necrosis of H9c2 myogenic cells upon transient energy deprivation. Rapid deenergization of mitochondria precedes necrosis and is controlled by reactive oxygen species, stress kinase JNK, HSP72 and ARC.

Subjecting myogenic H9c2 cells to transient energy deprivation leads to a caspase-independent death with typical features of necrosis. Here we show that the rupture of cytoplasmic membrane, the terminal event in necrosis, is shortly preceded by rapid depolarization of mitochondrial membranes. The rapid deenergization of mitochondria critically depended upon prior generation of reactive oxygen species (ROS) during ATP depletion stage. Accordingly, expression of catalase prevented mitochondrial depolarization and averted subsequent necrosis. Interestingly, trifluoperazine, a compound that protects cells from ischemic insults, prevented necrosis of H9c2 cells through inhibition of ROS production. Other factors that regulated the mitochondrial membrane depolarization and subsequent loss of plasma membrane integrity include a stress kinase JNK activated at early steps of recovery from ATP depletion, as well as an apoptotic inhibitory protein ARC. Accordingly, inhibition of JNK or overexpression of ARC prevented mitochondrial depolarization and rescued H9c2 cells from necrosis. ROS and JNK affected mitochondrial deenergization and necrosis independently of each other since inhibition of ROS production did not prevent activation of JNK, whereas inhibition of JNK did not suppress ROS accumulation. Therefore, JNK activation and ROS production represent two independent pathways that control mitochondrial depolarization and subsequent necrosis of cells subjected to transient energy deprivation. Overexpression of ARC, although preventing mitochondrial depolarization, did not affect either JNK activation or production of ROS. The major heat shock protein Hsp72 inhibited JNK-related steps of necrotic pathway but did not affect ROS accumulation. Interestingly, mitochondrial depolarization and subsequent necrosis can be suppressed by an Hsp72 mutant Hsp72DeltaEEVD, which lacks chaperone function but can efficiently suppress JNK activation. Thus, Hsp72 is directly implicated in a signaling pathway, which leads to necrotic death.

Adenosine Triphosphate↗

"Piecemeal" necrosis: renamed troxis necrosis.

Piecemeal necrosis, currently called interface hepatitis, is a feature of viral hepatitis as well as autoimmune hepatitis and steatohepatitis. The mechanism of liver cell loss and piecemeal necrosis needs to be determined. We hypothesize that piecemeal necrosis in hepatitis is due to a piecemeal removal of hepatocyte cytoplasm by lymphocytic ingestion. To test this hypothesis, 61 consecutive liver biopsies were examined by light microscopy, by immunohistochemistry and by electron microscopy, and the lymphocytic-hepatocytic interaction was morphologically assessed. In cases of hepatitis C, hepatitis B, autoimmune hepatitis, primary biliary cirrhosis, and steatohepatitis, piecemeal necrosis was found. Using cytokeratin stains, it was apparent that the lymphocyte-hepatocyte interaction and piecemeal necrosis leads first to binding of the lymphocyte to hepatocyte plasma membrane and then blebbing or indentation of the hepatocyte by the lymphocyte, followed by endocytosis of liver cell cellular components and digestion in the lymphocyte lysosomes. This process is repeated while the cytoplasm and the nucleus of the hepatocyte disappear bite by bite, and only nubbins of residual hepatocytic cytoplasm remain, either attached to intact hepatocytes or surrounded and sequestered within scar tissue and lymphocytes. We conclude that piecemeal necrosis is a gradual disappearance of hepatocytes as a result of lymphocyte-hepatocyte binding and ligand internalization of liver surface molecules by the lymphocyte. This gradual process leads to a slow reduction of hepatocyte size and eventual disappearance at the interface between the lobule and portal tracts. To term this new kind of necrosis, we propose the name troxis necrosis, after the Greek noun meaning "nibbling."

Biopsy↗

Extensive bone marrow necrosis in patients with cancer and tumor necrosis factor activity in plasma.

Tumor necrosis factor (TNF), a macrophage secretory protein produced by peripheral blood monocytes from patients with cancer, has been shown to possess cytotoxicity toward tumor cells in vitro. TNF in the blood of individuals with cancer is usually not detectable except with extremely sensitive radioimmunoassay or enzyme-linked immunosorbent assay (ELISA) methods. We have encountered two patients with the rare syndrome of extensive bone marrow necrosis in association with cancer. The first patient presented with marrow failure secondary to necrosis and was found to have adenocarcinoma in thoracic lymph nodes, lung, and marrow lymphatics at autopsy. Plasma tested at two dilutions (1:200 and 1:2,000) contained TNF at a concentration of 8.3 ng/ml, or 80 U/ml by a cytotoxicity assay using LM cells. The presence of TNF was confirmed with immunoblotting. The second patient had a poorly differentiated lymphoid tumor involving bone marrow, pancytopenia, and marrow necrosis. The plasma cytotoxicity assay indicated the presence of 0.7 ng/ml or 7 U/ml TNF. TNF was not detectable in plasma from six other patients with untreated cancer involving bone or bone marrow using either of our methods. The levels of TNF in the two patients with marrow necrosis were greater than those previously measured by others in patients with cancer but were comparable to those noted in patients with lethal sepsis. Since large doses of TNF have been shown to cause organ necrosis in animals, the data presented here are consistent with TNF involvement in mediating the observed marrow necrosis in our patients.

Adenocarcinoma↗

Structure/Function analysis of p55 tumor necrosis factor receptor and fas-associated death domain. Effect on necrosis in L929sA cells.

Tumor necrosis factor (TNF) induces a typical apoptotic cell death program in various cell lines by interacting with the p55 tumor necrosis factor receptor (TNF-R55). In contrast, triggering of the fibrosarcoma cell line L929sA gives rise to characteristic cellular changes resulting in necrosis. The intracellular domain of TNF-R55 can be subdivided into two parts: a membrane-proximal domain (amino acids 202-325) and a C-terminal death domain (DD) (amino acids 326-413), which has been shown to be necessary and sufficient for apoptosis. Structure/function analysis of TNF-R55-mediated necrosis in L929sA cells demonstrated that initiation of necrotic cell death, as defined by swelling of the cells, rapid membrane permeabilization, absence of nuclear condensation, absence of DNA hypoploidy, and generation of mitochondrial reactive oxygen intermediates, is also confined to the DD. The striking synergistic effect of the caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp(OMe)-fluoromethylketone on TNF-induced necrosis was also observed with receptors solely containing the DD. TNF-R55-mediated necrosis is not affected by the dominant negative deletion mutant of the Fas-associated death domain (FADD-(80-205)) that lacks the N-terminal death effector domain. Moreover, overexpression of FADD-(80-205) in L929sA is cytotoxic and insensitive to CrmA, while the cytotoxicity due to overexpression of the deletion mutant FADD-(1-111) lacking the DD is prevented by CrmA. These results demonstrate that the death domain of FADD can elicit an active necrotic cell death pathway.

Adaptor Proteins, Signal Transducing↗

Disruption of HSP90 function reverts tumor necrosis factor-induced necrosis to apoptosis.

Triggering tumor necrosis factor receptor-1 (TNFR1) induces apoptosis in various cell lines. In contrast, stimulation of TNFR1 in L929sA leads to necrosis. Inhibition of HSP90, a chaperone for many kinases, by geldanamycin or radicicol shifted the response of L929sA cells to TNF from necrosis to apoptosis. This shift was blocked by CrmA but not by BCL-2 overexpression, suggesting that it occurred through activation of procaspase-8. Geldanamycin pretreatment led to a proteasome-dependent decrease in the levels of several TNFR1-interacting proteins including the kinases receptor-interacting protein, inhibitor of kappa B kinase-alpha, inhibitor of kappa B kinase-beta, and to a lesser extent the adaptors NF-kappaB essential modulator and tumor necrosis factor receptor-associated factor 2. As a consequence, NF-kappa B, p38MAPK, and JNK activation were abolished. No significant decrease in the levels of mitogen-activated protein kinases, adaptor proteins TNFR-associated death domain and Fas-associated death domain, or caspase-3, -8, and -9 could be detected. These results suggest that HSP90 client proteins play a crucial role in necrotic signaling. We conclude that inhibition of HSP90 may alter the composition of the TNFR1 complex, favoring the caspase-8-dependent apoptotic pathway. In the absence of geldanamycin, certain HSP90 client proteins may be preferentially recruited to the TNFR1 complex, promoting necrosis. Thus, the availability of proteins such as receptor-interacting protein, Fas-associated death domain, and caspase-8 can determine whether TNFR1 activation will lead to apoptosis or to necrosis.

Amino Acid Substitution↗

[Idiopathic necrosis in the marrow of the distal femur. A contribution to aseptic necrosis of the bone (author's transl)].

Symmetrical aseptic necrosis in the marrow of the distal femur was systematically examined in 4 autopsies. According to formal analysis, the self reliant process, with a tendency toward relapse begins with two forms of destruction of the medullary fatty tissue. The consequences are fundamentally the same as those present after necrosis of the extra-medullary fatty tissue; there are only modifications caused location. These modifications include the regular calcification of non-liquifying by fatty-tissue necrosis that fibroses in a net-like manner, and of subsequent bone formation. Spongiosis in incorporated secondarily into necrosis. Medullary necrosis are not caused by vascular lesions and differ therefore from infarct-like necrosis of the bone. The etiology of the medullary steatonecrosis, which probably begins dystrophically, cannot be cleared up morphologically, and is unknown up to now. There are no definite indications for a causal relationship with cortico-steroid therapy. This form of necrosis of the marrow is therefore termed "idiopathic".

Adipose Tissue↗

Interaction between endotoxin and the antitumour agent 5,6-dimethylxanthenone-4-acetic acid in the induction of tumour necrosis factor and haemorrhagic necrosis of colon 38 tumours.

The investigational antitumour agent 5,6-dimethyl-xanthenone-4-acetic acid (5,6-MeXAA) induced dose-dependent haemorrhagic necrosis of colon 38 tumours to a similar extent to that induced using bacterial lipopolysaccharide (LPS). TNF-alpha activity in serum and mRNA for TNF-alpha in splenocytes were induced over a broad range of LPS doses, whereas with 5,6-MeXAA, induction occurred only at concentrations approaching the maximum tolerated dose. At concentrations that provided similar degrees of haemorrhagic necrosis, the levels of serum TNF-alpha induced using 5,6-MeXAA were 100-fold lower than those obtained with LPS, indicating that haemorrhagic necrosis was not directly correlated with TNF-alpha levels. There was also no correlation between the degree of tumour necrosis and the duration of growth delay. Treatment with LPS did not induce a significant delay in growth, despite extensive tumour haemorrhagic necrosis, whereas with 5,6-MeXAA, treatments that improved the cure rate did not necessarily give longer growth delays. Therapy using a combination of sub-optimal doses of both compounds was synergistic for the induction of serum TNF-alpha and message for TNF-alpha but was not synergistic for antitumour efficacy. Thus, no correlation is evident between cure rates, duration of growth delay, haemorrhagic necrosis and TNF-alpha induction by 5,6-MeXAA or LPS.

Animals↗

Glucocorticoid-mediated inhibition of endotoxin-induced intratumor tumor necrosis factor production and tumor hemorrhagic necrosis and regression.

Intravenous injection of 25 micrograms of bacterial endotoxin on day 9 of growth of the SA1 sarcoma results in extensive necrosis of the core of this tumor and in its subsequent complete regression. Tumor hemorrhagic necrosis and regression failed to occur in mice that were given a subcutaneous injection of cortisone acetate or dexamethasone 12 h before being giving endotoxin. Inhibition of tumor hemorrhagic necrosis and regression by glucocorticoids was associated with inhibition of endotoxin-induced intratumor TNF production that normally takes place several h after endotoxin is given. In contrast, glucocorticoids had no effect on the ability of intravenously injected rTNF to cause tumor hemorrhagic necrosis and regression. The results lend further support to the belief that TNF is the predominant mediator of endotoxin-induced hemorrhagic necrosis of established murine tumors, and that hemorrhagic necrosis is a prerequisite for the immunologically mediated regression that follows.

Animals↗

Role of lipopolysaccharide and tumor necrosis factor-alpha in induction of hepatocyte necrosis.

The occurrence of acute hepatic failure during systemic inflammatory response syndrome (SIRS) is related to the extent of hepatocyte (HC) damage and cell death resulting from necrosis or apoptosis. We hypothesized that proinflammatory mediators such as lipopolysaccharide (LPS) and tumor necrosis factor-alpha (TNF-alpha) can, either directly or indirectly through neutrophil (PMN) and Kupffer cell (KC) activation, induce HC damage and cell death, and that the mechanism is cellular necrosis rather than apoptosis. The results in this study demonstrated that LPS and TNF-alpha alone and in combination are directly cytotoxic to cultured rat HC as indicated by the hepatocellular enzyme release and HC necrosis. However, LPS and TNF-alpha, in the presence of sodium arsenite (a heat shock inducer), were unable to induce HC apoptosis. Both KC and PMN activated by either LPS or TNF-alpha induced significant hepatocellular enzyme release and HC necrosis, which was dependent on the ratio of KC and PMN to HC. It is concluded that LPS and TNF-alpha may play a central role in the development of acute hepatic failure after severe trauma and sepsis by directly or indirectly inducing HC necrosis rather than apoptosis.

Animals↗

Bowel necrosis induced by tumor necrosis factor in rats is mediated by platelet-activating factor.

We have developed a rat model of ischemic bowel necrosis associated with shock by injection of platelet-activating factor (PAF) or a combination of PAF and endotoxin. Recent investigations have shown that tumor necrosis factor (TNF) also induces shock and necrosis of the gastrointestinal tract. The morphological changes of TNF-induced bowel lesions are indistinguishable from those caused by PAF. The mechanism of TNF-induced bowel necrosis is unclear. In the present study, we have shown that (a) TNF caused PAF production in bowel tissue; (b) the effects of TNF and LPS on PAF production in the intestine are additive; (c) TNF and LPS are synergistic in inducing bowel necrosis; and (d) TNF-induced bowel necrosis is due to PAF release and can be prevented by pretreatment with PAF antagonists.

Animals↗

[The effect of tumor necrosis factor alpha on hepatic necrosis in viral hepatitis].

In order to investigate the effect of tumor necrosis factor alpha (TNF alpha) on hepatocyte necrosis in viral hepatitis, TNF alpha with or without D-galactosamine (D-Gal) was injected into the abdominal cavity of rats. No effect was observed after injection of TNF alpha alone. After injection of TNF alpha with D-Gal, the total bilirubin level in rat blood increased and hepatocyte necrosis appeared (P < 0.05). Moreover, anti-TNF alpha McAb blocked the effect of hepatocyte necrosis produced by D-Gal and lipopolysaccharide (LPS). 130 samples of hepatic tissue were stained with anti-TNF alpha McAb by using ABC immunohistochemistry method. It was found that more severe the hepatocyte necrosis, more the positive cells expressing TNF alpha. There were more TNF alpha positive cells in the tissue of severe hepatitis. These results suggested that TNF alpha is a mediator in hepatocyte necrosis.

Adult↗

Haemorrhagic tumour necrosis following endotoxin administration. I. Communication: morphological investigation on endotoxin-induced necrosis of the methylcholanthrene (Meth A) tumour in the mouse.

Endotoxin induced necrosis of the Meth A mouse tumour has been investigated using macroscopic, histological and ultrastructural examination methods. On the 8th day after tumour cell transplantation, the animals received a relatively non-toxic dose of the Salmonella abortus equi endotoxin intravenously. The natural history of the tumour necrosis took the following course: The earliest morphological changes could be seen with the electron microscope 90 min after administration of the endotoxin, and were seen as an interstitial oedema with separation of the tumour cells. Haemorrhagic necrosis of the tumour was complete 4 hours after injection, and could be easily recognized with the naked eye. Rejection of the necrotic malignant tumour was complete two weeks after LPS administration. Only minor residual scarring of the belly-wall remained. Haemorrhagic tumour necrosis due to endotoxin can be compared with the localized Shwartzman reaction and probably involves tumour necrotizing factor (TNF). For complete destruction of a tumour by haemorrhagic necrosis the size of the tumour is critical. Certain regression after endotoxin administration depends upon additional T-cell-mediated immunity (provided the tumour is immunogenic). In contrast to the haemorrhagic necrosis, BCG-induced tumour regression is accompanied by granulomatous inflammation, which may be responsible for destruction of the tumour.

Animals↗

Progressive outer retinal necrosis and acute retinal necrosis in fellow eyes of a patient with acquired immunodeficiency syndrome.

PURPOSE: To describe an unusual concurrence of acute retinal necrosis and progressive outer retinal necrosis in fellow eyes of a patient with acquired immunodeficiency syndrome (AIDS). METHODS: Interventional case report. In a 37-year-old man with AIDS and herpes zoster keratitis in the right eye, progressive outer retinal necrosis developed in the right eye and acute retinal necrosis developed in the left eye. RESULTS: Disparate presentations of retinitis persisted in each eye, and retinal detachment and vision loss ensued in both eyes despite antiviral therapy. CONCLUSION: Distinct features of acute retinal necrosis and progressive outer retinal necrosis do not necessarily reflect systemic factors, and they may be variant manifestations of the same underlying infection.

Acquired Immunodeficiency Syndrome↗