Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026918 (Mycobacterium)
 52,428 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

3 biopsies of 3-5 week-old nodular lesions in 2 patients with so-called swimming-pool (aquarium-) granuloma have been examined by electron microscopy. The cytohistological spectrum simultaneously comprises acute exudative as well as chronic proliferative phenomena. Epithelioid cells and collagen producing fibroblasts are already conspicious in 3 week-old granuloma. According to the cytological composition the Mycobacterium marinum granuloma represents a high-turnover granuloma with immunogenic origin. It is comparable to mycobacterial diseases in the presence of well developed cell mediated immunity (Lupus vulgaris, tuberculoid leprosy). Degrading mycobacteria have been rarely detected in phagocytes and are compared with viable bacilli in macrophages of experimentally infected mice. Curved and annular parallel membranes ("worm-like structures") in the cytoplasm of transformed macrophages and in fibroblasts presumably originate from the membranes of endoplasmic reticulum. Cord-like structures with transverse bands (periodicity 170-180 A) in the lumen of RER of some fibroblasts are interpreted as intracellularly aggregated collagen precursors.
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PMID:The ultrastructure of mycobacterium marinum granuloma in man. 68 31

Mice of the inbred strains C57BL and C3H were inoculated in the foot-pads with Mycobacterium lepraemurium (MLM) and the inflammatory reaction was studied using light and electron microscopy. In C57BL mice a granulomatous reaction developed 3-4 weeks after inoculation. The inflammatory exudate at this stage showed numerous lymphocytes, monocytes and macrophages. The latter cell type often contained many lysosomes and appeared activated. The bacilli which were all within phagosomes showed extensive electron dense aggregates of the cytoplasm suggesting severe damage. Lymphocytes and macrophages in close contact with each other were often observed. In macrophages which contained damaged bacilli, spherical lipid-like bodies surrounded by granular endoplasmic reticulum were observed. It is suggested that this cell product could be of some significance for the bactericidal function of the macrophage. Contrary to these findings, the cellular infiltrate developing in C3H mice showed no lymphocytes and consisted exclusively of macrophages. These were all heavily loaded with bacilli. The vast majority of bacilli encountered in this strain was morphologically intact and presumably viable. Lipid-like bodies similar to those observed in infected C57BL macrophages were not encountered in C3H mice. It is concluded that unless the infected macrophages become immunologically activited they are unable to cause bacterial damage or to inhibit the growth of MLM.
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PMID:Experimental murine leprosy. 8. Ultrastructural features of the inflammatory exudate and bacterial morphology in C3H and C57BL mice after foot-pad inoculation with Mycobacterium lepraemurium. 110 68

Yersin's type of experimental tuberculosis was induced in rabbits by intravenous administration of Mycobacterium avium and was studied in situ in the liver. Mycobacteria were only found in Kupffer-cell phagosomes and, at the later stages of the disease, in the phagosomes of the multinuclear giant cells. Ultrastructural changes in Kupffer's cells amounted to an increase in cytoplasm volume and corresponding increase in the number of ribosomes, endoplasmic reticulum and mitochondria. As compared with control animals, Kupffer's cells were more frequent in the experimental rabbits, clustering around sinusoid capillaries. Characteristic changes in mycobacterium ultrastructure were cytoplasmic vacuolisation in some individuals and an almost regular presence of high-density polymorphous structures. The microbial cell walls remained intact.
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PMID:Endocellular parasitism of Mycobacterium avium in rabbit liver. A morphological study. 123 79

Granulomas which develop in draining lymph nodes, following the intradermal injection of cobalt-irradiated Mycobacterium leprae into the ear of the guinea pig 2 and 5 weeks earlier, were studied in animals which had been presensitized with BCG vaccine or M. leprae and compared with granulomas that developed in previously unsensitized guinea pigs. Presensitization with mycobacteria accelerated the development of the granulomas. Granulomas in previously unsensitized guinea pigs were found ultrastructurally to contain phagocytosing macrophages similar to those in lepromatous leprosy, and M. leprae presensitization did not alter the type of granuloma found. Those in BCG-presensitized guinea pigs contained secretory epithelioid cells with rough endoplasmic reticulum similar to those found in borderline tuberculoid leprosy or reversal reactions. The significance of these findings in relation to the current use of vaccines in leprosy is discussed.
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PMID:Effect of presensitization with BCG and Mycobacterium leprae on granuloma formation to M. leprae. 228 Jan 18

Spiral ganglia of guinea pig and mouse were investigated by scanning electron microscopy (SEM). The cochlea was freeze-fractured and then macerated with 0.1% OsO4 solution for 70-90 h (A-O-D-O method (1]. This allowed three-dimensional observation of the general view of the spiral ganglion and the intracellular structure. Two types of spiral ganglion cell, type I and type II, could be distinguished by the A-O-D-O method. Intracellular membranous structures such as mitochondria, endoplasmic reticulum (ER) and Golgi apparatus were also demonstrated stereoscopically. Furthermore, morphological changes in mouse spiral ganglion cells due to injection of Mycobacterium fortuitum were observed, using SEM. The degenerative process began as swelling of the mitochondria. When Schwann cell became affected, the myelin sheath disappeared and the ganglion cell border became indistinct. This degeneration developed rapidly, suggesting a direct influence of the bacteria on the ganglion cell. Various types of inclusion body with limiting membrane could be demonstrated stereoscopically. As Romand & Romand (4) suggested, these inclusion bodies may be remnants of cellular organellae or various type of lysosomes.
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PMID:Three-dimensional observation of the spiral ganglion cell. Normal structure and pathological changes. 275 30

A comparison is made between immunologically induced and non-immunologically induced granulomas in guinea-pigs injected with metals (zirconium and aluminum) or with mycobacteria (BCG vaccine and Mycobacterium leprae). Immunological granulomas were characterized by epithelioid cells and fibrosis, whereas non-immunological granulomas contained phagocytosing macrophages with little evidence of fibroblast activation. Epithelioid cells carry the same specific macrophage antigen as phagocytosing macrophages and this can be detected by the use of a specific monoclonal antibody. However, they differ from phagocytosing macrophages in that they are poorly phagocytic, not glass adherent and lack Ia antigen. They are however secretory cells with rough endoplasmic reticulum. A relation between the presence of these cells and increased collagen synthesis is indicated. A study of accessory cell function showed that the epithelioid cells of BCG granulomas were able to support mitogen-induced but not antigen-induced proliferation of T lymphocytes. The macrophages of M. leprae granulomas did not support either a mitogen- or antigen-induced proliferative response.
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PMID:The mononuclear phagocyte system in granulomas. 401 81

Rats given a single subdermal injection into the left hind paw of 0.5 mg Mycobacterium tuberculosis suspended in 0.1 ml of mineral oil, after several days of latency, developed arthritis accompanied by depression in liver microsomal phosphatidylcholine and phosphatidylethanolamine synthesis at 7, 14 and 21 days. The depression of liver microsomal phosphatidylcholine and phosphatidylethanolamine concentrations of experimental animals was accompanied by decreased incorporation of radioactive palmitate into both phospholipids. Nevertheless, the biosynthesis of phosphatidylcholine via the methylation pathway was unaffected. These observations suggest that adjuvant arthritis affects quantitatively the phospholipid composition of the liver endoplasmic reticulum, which consequently may lead to impairment of the microsomal drug-metabolizing enzyme system.
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PMID:The effect of adjuvant-induced arthritis on rat liver microsomal phospholipid metabolism. 407 96

Systemic infection of mice with Mycobacterium BCG leads to focal liver damage by producing many granulomas. By undefined mechanisms, this infection markedly enhances the animal's susceptibility to the lethal effect of endotoxin. Small doses of endotoxin given to BCG-infected mice were found to cause acute hepatic damage, as demonstrated by elevated activities of liver enzymes in serum and by morphologic alterations documented by light and electron microscopy and by histochemical technics. The morphologic alterations caused by endotoxin included glycogen depletion, mitochondrial swelling, disruption of the continuity of sinusoidal endothelium and focal injury characterized by marked vacuolization of hepatocytes and distension and fragmentation of rough endoplasmic reticulum. Histochemical studies revealed the apparent release of acid phosphatase from granules in the central portions of granulomas, and the release of beta-glucuronidase from the cytoplasm of hepatocytes.
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PMID:Endotoxin-induced hepatic damage in BCG-infected mice. 455 21

The dermal lesions of 18 patients with leprosy have been examined by transmission electron microscopy. The patients exhibited a spectrum of disease from polar lepromatous to polar tuberculoid with intermediate stages in various states of therapy and relapse. The nature and quantities of inflammatory cells and bacteria have been determined by electron microscopy to supplement previous light and fluorescence microscopy studies. Lepromatous leprosy was characterized by many parasitized foam cells containing large, multibacillary vacuoles with intact, osmiophilic Mycobacterium leprae: Bacteria were embedded in an electron-lucent matrix. No extracellular bacteria were evident. Only small numbers of scattered lymphocytes were found. As one approached the borderline state, smaller numbers of bacilli were present as singlets and doublets in small vacuoles of macrophages. The more reactive forms showed increasing bacillary fragmentation, larger numbers of lymphoid cells, and an occasional epithelioid cell. At the tuberculoid end of the spectrum, clear evidence of an exuberant lymphocyte response was evident. Large numbers of T cells with extremely long and complex filipodia were closely associated with epithelioid and multinucleated giant cells. Many of the mononuclear phagocytes appeared nonviable, and areas of necrosis were evident. Bacillary remnants were scarce and the cytoplasm of the epithelioid cells contained occasional dense bodies and many stacks of endoplasmic reticulum and mitochondria. These results suggest that Leu 3a/OKT4 helper cells may be capable of driving the effector function of mononuclear phagocytes. This would lead to a significant microbicidal effect on M. leprae, perhaps through the production of toxic oxygen intermediates.
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PMID:The cutaneous infiltrates of leprosy. A transmission electron microscopy study. 635 48

Epithelioid cells are cells of the mononuclear phagocyte system found in certain granulomas mainly associated with intense immunological activity. These cells show little phagocytic activity. In certain experimental granulomas such as those produced in guinea pigs sensitive to zirconium, and at sites of intense inflammatory reaction in man, they may contain varying amounts of rough endoplasmic reticulum ("secretory" epithelioid cells). In other situations such as tuberculoid leprosy and in some cases of sarcoidosis they may have the appearance of activated macrophages or take on a multivesicular appearance ("vesicular" epithelioid cells). It is suggested that "vesicular epithelioid cells could develop from "secretory" epithelioid cells by a process of degeneration. In studies comparing granulomas induced in lymph nodes draining the site of intradermal injection of mycobacteria, epithelioid cell granulomas were produced with BCG vaccine, whereas, the granulomas induced by Mycobacterium leprae contained undifferentiated macrophages that contained phagocytosed organisms. The BCG granulomas were in addition characterised by fibroblast infiltration, the presence of collagen and resolution by fibrosis. M. leprae granulomas showed little evidence of fibroblastic activity. Biochemical studies confirmed that BCG granulomas formed new collagen in vitro, whereas this did not take place with M. leprae granulomas. It is suggested that epithelioid cells could play an important role in fibrosis possibly by the secretion of a fibroblast activating factor.
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PMID:The origin, morphology, and function of epithelioid cells. 704 74


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