Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.17 (lysozyme)
 21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Macrophages play critical roles in both degenerative and regenerative processes following peripheral nerve injury. These include phagocytosis of debris, stimulation of Schwann cell dedifferentiation and proliferation, and salvage of myelin lipids for reutilization during regeneration. To better define the role of macrophages, we studied models of primary demyelination (tellurium intoxication) and secondary demyelination (nerve crush and cut). Sections of paraformaldehyde-fixed rat sciatic nerves at various stages of demyelination were stained with monoclonal antibody ED1, a standard macrophage marker, and a polyclonal antiserum specific for lysozyme (LYS). Near the peak of demyelination in all three models, LYS immunoreactivity colocalized with ED1 staining. Macrophages present in nerve after the period of maximal phagocytosis of myelin were much less immunoreactive for LYS. These results suggest LYS is a good marker for macrophages which are active in phagocytosis. Tellurium intoxication, which causes synchronous demyelination and subsequent remyelination of only about 25% of myelin internodes, recruited more macrophages (and induced more lysozyme expression) than either nerve crush or cut, which cause demyelination of all internodes distal to the injury site. This suggests that Schwann cells may recruit macrophages soon after metabolic insult and prior to actual demyelination. The final signal for macrophage recruitment is not directly related to the amount of damaged myelin. In the models listed above, steady state mRNA levels for apolipoprotein E (ApoE; possible mediator of cholesterol salvage), LYS, and P0 (major structural protein of PNS myelin), were analyzed by Northern blot analysis. LYS mRNA levels peaked sharply in all models, with a temporal pattern consistent with the expected presence of activated, phagocytic macrophages.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Macrophage recruitment in different models of nerve injury: lysozyme as a marker for active phagocytosis. 771 30

In order to determine the origin of brain phagocytes brain slices and optic nerve segments from adult Lewis rats were transplanted into the peritoneal cavity of syngenic recipients. The specimens were contained in Millipore diffusion chambers fitted with membranes of either 0.22 or 5.0 microns pore size. The either blocked or allowed the access of non-resident cells. Each recipient rat received both a 0.22 and 5.0 microns pore chamber. Later (3-16 days), the specimens were recovered and analyzed by monoclonal antibody techniques and electron-microscopy. Endothelia, GFAP+ astrocytes, ED1-/ED2+/RCA-1+/OX-6-perivascular cells and ED1-/ED2-/RCA-1+/lysozyme--microglia were found to have survived the procedure. Cells of the macrophage phenotype (ED1+/ED2+/RCA-1+/lysozyme+/vimentin+ with phagocytic vacuoles), however, were only found in large numbers in specimens kept within 5.0 microns pore size chambers, giving access to non-resident cells, and were exceedingly rare in specimens from 0.22-micron pore chambers. It has been concluded that the majority of brain phagocytes found after lesions do not originate from microglia or perivascular monocytic cells, but rather from invading cells.
 ...
PMID:Origin of macrophages in central nervous tissue. A study using intraperitoneal transplants contained in Millipore diffusion chambers. 822 59

Rat optic nerves were subjected to crush injury to study the local tissue reactions leading to wound healing and tissue repair. We used antibodies against glial fibrillary acidic protein (GFAP), vimentin, the S1OO protein (S1OOP), lysozyme, and ED1 as markers for astroglial cells and microglia/macrophages at the light and electron microscopic level during the 3 weeks following the crush. The crush injury produced a vast area of tissue damage including the disruption of the blood-brain barrier (BBB). In the first days after crushing, astrocytes were absent from the lesion site. S1OOP-positive astrocytes reappeared in the lesion center as early as 6 days after crushing. These astrocytes reestablished former topological structures such as perivascular and subpial glia limitans. At the edges of the lesion site reactive astrocytes enclosed and embedded axonal and myelin debris. Preceding the astroglial repopulation, a massive infiltration of microglia/macrophages (phagocytes) into the lesion center took place. ED1-positive/lysozyme- positive cells of round shape were seen in the lesion center at 2 days after crushing, and their number peaked around 1 week after crushing. They efficiently cleared the debris from the lesion site and mostly disappeared after 3 weeks. With immuno-electron microscopy we found the ED1 antigen related to the membranes of phagosomes. The microglia/macrophages observed in the nerve segments distal of the lesion (Wallerian degeneration site) were different from those in the lesion center: 1) they appeared later, about 6 days after crushing; 2) they were ED1 positive, but lysozyme negative and showed a branched morphology; and 3) they persisted in the distal nerve segment but showed little phagocytosis. We suggest that these cells are mostly activated microglia.
 ...
PMID:Cellular reactions at the lesion site after crushing of the rat optic nerve. 883 93

A transplantable tumour (HS-J) was established from a spontaneous histiocytic sarcoma found in a 24-month-old male F344 rat. Serial transplantations (seven generations) were made in syngeneic male and female rats by means of intraperitoneal or subcutaneous implants, with a 100% take rate. Rats given HS-J implants developed large nodules locally, with metastasis to distant organs. HS-J tumours consisted mainly of round to oval cells with abundant cytoplasm, arranged in a compact sheet. Enzyme- and immuno-histochemical examination showed that neoplastic cells reacted with ED1 (rat monocyte/macrophage-specific antibody), lysozyme, alpha 1-antitrypsin and lysosomal enzymes (acid phosphatase and non-specific esterase), indicating derivation from cells of the monocyte/macrophage lineage. The majority of neoplastic cells were negative for ED2 (rat tissue macrophage-specific antibody). Abnormal accumulations of hyaline droplets in the proximal renal tubular epithelial cells were seen in HS-J-bearing rats. The droplets were faintly immunopositive for lysozyme, but negative for alpha-2u globulin and albumin. It was considered that excessive production of the protein by tumour cells might lead to subsequent overload in renal tubules. HS-J may prove beneficial for studying the biological behaviour of monocyte/macrophage-derived tumours in the rat.
 ...
PMID:Morphological characteristics of a transplantable histiocytic sarcoma (HS-J) in F344 rats and appearance of renal tubular hyaline droplets in HS-J-bearing rats. 907 2

With future exploration of macrophage properties in mind, we established a novel cell line (HS-P) from a transplantable histiocytic sarcoma, derived originally from a tumour in an aged F344 rat. HS-P was subjected to 70 serial passages, in which the mean doubling time was 15.7 h. The cells, which were round, oval or polygonal in shape, were arranged in a compact sheet. They reacted to varying degrees for lysosomal enzymes (acid phosphatase and non-specific esterase) and with the following antibodies: ED1/ED2 (rat macrophage/histiocyte-specific), OX6 (rat MHC class II-specific), lysozyme antibody and alpha1-antichymotrypsin antibody. Electron microscopically, HS-P cells showed lysosomes and prominent cell projections. These findings indicated that the cultured cells were macrophage-like. Syngeneic rats inoculated subcutaneously or intraperitoneally with HS-P cells invariably developed sarcomatous tumours consisting of monomorphic mononuclear cells, which exhibited cytochemical properties similar to those of cultured HS-P cells. Bioassay and reverse transcription-polymerase chain reaction methods revealed that tumour necrosis factor-alpha increased on addition of lipopolysaccharide (LPS), indicating that HS-P cells remained LPS-responsive. HS-P cells may prove to be a useful tool for in-vitro studies of macrophage function.
 ...
PMID:Macrophage-like cell line (HS-P) from a rat histiocytic sarcoma. 1122 16

The present report describes a rare case of spontaneous primary histiocytic sarcoma of the popliteal lymph node in a 19-week-old female Sprague-Dawley (SD) rat. At necropsy, a 10 mm-diameter whitish nodule was found at the site of the femoral muscle in the right hindlimb. Histopathologically, the nodule comprised large pleomorphic histiocyte-like cells with abundant eosinophilic or foamy cytoplasm. Multinucleated giant cells, necrotic foci surrounded by palisading arrays of epithelioid histiocyte-like cells and phagocytosis of cell debris or erythrocytes by the neoplastic cells were occasionally observed. Invasion of the tumor cells into the surrounding adipose tissue was found focally, but there were no distal metastases. Immunohistochemically, the neoplastic cells were positive for vimentin, CD68 (ED1) and lysozyme. We concluded that this tumor occurred in the popliteal lymph node, considering the anatomical location of the lesion and the presence of the remnants of lymphoid tissue involved in the tumor.
 ...
PMID:Spontaneous histiocytic sarcoma of the popliteal lymph node in a young sprague-dawley rat. 2227 28