Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0026916 (MAC)
 5,226 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The primary hyperplastic nature of palisaded encapsulated neuromas (PENs) has been recently challenged by suggesting a traumatic origin. We studied eight cases of traumatic neuroma (TN) and 12 cases of PEN by routine light-microscopic, histochemical, and immunohistochemical methods to assess evidence of previous tissue injury. Sections from the formalin-fixed, paraffin-embedded tissue were stained with hematoxylin-eosin, trichrome, elastic, reticulin, Giemsa, colloidal iron (with and without hyaluronidase), and Bielschowsky silver stains. Antibodies were applied to collagen types I, III, and IV, MAC 387, factor XIIIa, alpha 1-antitrypsin (A1AT), epithelial membrane antigen (EMA), Leu-7, and myelin basic protein using ABC techniques. We found that (a) in TN the individual fascicles were usually surrounded by perineurial cells, whereas in PEN the perineurial cells were observed mainly in the capsular areas and only rarely within the fascicles as evidenced by EMA antibodies; (b) histochemically TN contained considerably larger amounts of collagen (types I and III), acidic mucin, and myelin products than did PEN; and (c) neither PEN nor TN contained increased inflammatory cells or cells positive for factor XIIIa, MAC 387, or A1AT. We conclude that (a) there are substantial structural and histochemical differences between TN and PEN, (b) the changes suggest that the classic form of PEN has a different histogenesis than TN, and (c) on histologic grounds, chronic minor trauma could not be excluded as an etiologic factor for PEN.
 ...
PMID:Comparative light-microscopic and immunohistochemical study of traumatic and palisaded encapsulated neuromas of the skin. 128 69

Bone marrow biopsies from 125 patients at different stages of HIV infection were examined and the histopathological changes are described. Indications for biopsy included peripheral blood abnormalities, search for opportunistic pathogens, a suspected lymphoma or evaluation of its progression. Common histopathological features, suggestive of HIV infection but non-pathognomonic, were: severe hypercellularity (43.2%), myelodysplasia (74.4%), plasmocytosis (86.4%), and lymphocytic (36.8%) and histiocytic infiltrates with or without granulomas (20%). Reticular fibrosis (58.6%), iron deposits (59.2%), vascular congestion and mucoid degeneration of fat (18.4%) were frequently observed. Hypoplasia was usually a late-occurring event and/or may have been iatrogenic. Opportunistic infections were detected in 8 patients: Mycobacterium avium intracellulare (4 cases), Mycobacterium tuberculosis (1 case), Cryptococcus neoformans (1 case), and Leishmania (1 case). Neoplastic complications were found in 3 patients: Burkitt's lymphoma (1 case) and Hodgkin's disease (2 cases). The pathophysiological mechanisms envisaged include the effect of HIV infection on precursor cells in the bone marrow.
 ...
PMID:[The bone marrow in human HIV infection. A bioptic study of 125 cases]. 152 53

Laminated iron concretions were noted in the liver of an aged siamang (Hylobates syndactylus) that had granulomatous enteritis and hepatitis due to Mycobacterium avium intracellulare infection. Preexisting hepatic siderosis, iron sequestration in macrophages, and compromised macrophage function due to mycobacterial infection are proposed as the basis for the abundance and size of the concretions. Similar siderophilic bodies and concomitant siderosis occurred in other siamangs. The concretions are similar to Schumann bodies and Michaelis-Gutmann bodies associated with granulomatous disease in other species.
 ...
PMID:Siderophilic bodies associated with hemosiderosis and atypical mycobacterial infection in an island siamang (Hylobates syndactylus). 192 Mar 83

The histopathologic changes of bone marrow during infection with the human immunodeficiency virus type 1 (HIV-1) are described. Bone marrow biopsies from 73 patients at different stages of HIV-1 infection were studied. Indications for biopsy included peripheral blood abnormalities, suspicion of lymphoma, or search for specific pathogens. Common histopathological features, suggestive of HIV-1 infection but nonpathognomonic were hypercellularity (67%), myelodysplasia (86.1%), plasmacytosis (98.6%), lymphocytic infiltration (31.1%) and histiocytic infiltration with or without granulomata (13.7%). Increases in reticulin fibers (54.7%), and stainable iron deposits, vascular congestion and serous atrophy of fat were frequent features. Opportunistic infections and neoplastic complications were detected in 7 cases: pathogens were demonstrated in 4 cases (Mycobacterium avium intracellulare (MAI), Cryptococcus neoformans, Toxoplasma gondii and Leishmania) and lymphoma in 3 cases (1 Burkitt lymphoma and 2 Hodgkin's disease). Bone marrow hypoplasia is usually a terminal event in AIDS and may be iatrogenic.
 ...
PMID:Bone marrow findings in HIV infection: a pathological study. 210 65

The mineral pigments and ferric oxide dyes are used on a large scale in the paint and varnish industry, in building, chemical industry, polygraphy etc. For their production as basic raw materials are used lead, chromium and iron compounds. The concentrations of the toxic and accummulating lead and chromium in the air of the work environment surpass MAC and create most frequently "especially unfavourable" conditions of work. In all industrial processes the leading unfavourable factor is the chemical combined with unfavourable physical factors and overstress on the locomotor system. Changes were established in the organism of examined workers as result from the chronic effect of the factors of the work environment of the peripheral blood, digestive, nervous system and the skin. In view of reducing the risk of exposure to the toxic chemical factor it is imposed to take measures for sanitation of the work environment.
 ...
PMID:[The occupational risk in the manufacture of mineral pigments and iron oxide dyes]. 324 91

The spreading of needle-like minerals in the country is studied, which are of no industrial importance, but are contained in some of course and nonmetallic mineral raw materials. On the basis of their classification are chosen standards: sepiolite, wollastonite, palygorskite, etc., and their dispersion in needle-like fine dispersive particles, is studied. On the basis of a preliminary prognosis are established needle-like particles in ore dust of one iron ore location. The importance of the needle-like nonasbestos components can be expressed with "dose" inhaled needles on the basis of the concentration of the needle-like components, the duration of one work shift and the work load in a definite work operation. The quantity of inhaled needles by an operator on a filling machine for mineral flour, containing minimum quantity of needles (0.5%) with pollution above MAC is near to that during packing of asbestos. The results received are useful for future classification of the biological activity of needle-like nonasbestos components.
 ...
PMID:[Needle-like nonasbestos particles in Bulgarian mineral raw materials]. 324 96

Abnormalities in iron metabolism have been reported in patients with acquired immunodeficiency syndrome (AIDS). To assess the frequency of abnormal hepatic iron deposition in these patients and to examine potential causes of iron overload, we analyzed the amount of iron at different cellular sites in liver sections obtained at autopsy of 78 patients with AIDS. Quantitation of serum iron and transferrin levels and estimation of total iron binding capacity was obtained using serum from 63 patients. The number of whole blood/packed red blood cell transfusions and opportunistic infections was recorded. Of the 78 patients, 25 (32%) showed a Grade 3 or 4 (0-4 scale) iron level, distributed in three patterns, i.e., in hepatocytes only, in hepatocytes and Kupffer cells, and in Kupffer cells only. In these 25 livers, 4 had cirrhosis, with no documented cause; the mean number of transfusions was 12.5; and 16 (64%) had Mycobacterium avium-Mycobacterium intracellulare infection. In the 53 livers with little or no iron, 5 had cirrhosis, with 3 of those 5 listing alcoholic liver disease or hepatitis as the cause; the mean number of transfusions was 1.4; and 18 (34%) had Mycobacterium avium-Mycobacterium intracellulare infection. Transferrin saturation was more than 50% in 6 (29%) of 21 cases with increased hepatic iron levels and in 6 (14%) of 42 cases with little or no hepatic iron. These results indicate that hepatic iron overload in patients with AIDS is associated with blood transfusions, an elevated transferrin saturation, and Mycobacterium avium-Mycobacterium intracellulare infection. Significant hepatic iron deposition in patients with AIDS with no other apparent cause of cirrhosis suggests an etiologic role for iron in hepatic injury. The increase in hepatic iron levels in these patients has potentially adverse clinical effects related to the use of transfusions, iron supplements, and iron-containing drugs.
 ...
PMID:Increased hepatic iron in the acquired immunodeficiency syndrome: an autopsy study. 938 70

One of the most obvious problems one perceives when working with Mycobacterium avium isolates is the vast array of phenotypes expressed with regard to colonial morphotype, serovar and particularly virulence. Thus whenever experimental data derived from different MAC isolates is compared the variety of this group of mycobacteria must always be considered. Another issue of concern is the extrapolation of in vitro data to the in vivo disease. We have reported, in the past, that survival in murine macrophage culture does not always correlate with survival in vivo (23). It is plausible therefore, that the pathways outlined in section 5.2 and figure 3 play a crucial role in the initiation of the innate immune response in general and that there are components of this response which are not expressed by IFN-gamma activated macrophages but which are necessary for bacterial control. In conclusion, we suggest that the initial control of MAC infection requires a healthy lung (or gut) architecture and that control by unactivated macrophages includes respiratory burst activity and also the sequestration of free iron away from the mycobacterial phagosome. Acquired immunity is important in controlling bacteria which have overcome the innate response and this control is mediated by cytokine activation of infected macrophages. Finally, we have described an animal model of infection in which uncontrolled bacterial growth occurs and in which lesions similar to those seen in AIDS patients develop.
 ...
PMID:Immunopathogenesis of Mycobacterium avium infection. 969 55

Earlier in vitro studies demonstrated the remarkable potency of the lazaroid compounds to prevent oxidant-induced early cell injury. However, the ability of lazaroid compounds to limit oxidative injury in vivo(including renal ischemia-reperfusion) has been less certain, and the early clinical trials using lazaroids to limit CNS injury or organ injury in the setting of transplantation have not been promising. Lazaroid compounds are potent inhibitors of lipid peroxidation, and their inability to influence other key injury processes, particularly during the late stages of cell injury, might partly explain the limited clinical efficacy. To test this, renal tubular (LLC-PK1) cells were incubated with 250 micromH(2)O(2)for 135 min, in the presence or absence of 2-methyl aminochroman (2-MAC, U-83836E), a lazaroid with potent ability to inhibit lipid peroxidation, or desferrioxamine, (DFO) an iron chelator with broader antioxidant efficacy. Cell injury, lipid peroxidation, DNA damage and ATP depletion were measured in the early (immediately after H(2)O(2)incubation) and late (24 h after H(2)O(2)incubation) stages of cell injury. In the early stage, 2-MAC suppressed H(2)O(2)-induced lipid peroxidation and LDH release, but not the DNA damage, ATP depletion or loss of cell replication. In contrast, DFO suppressed all of the measurements. In the late stages, despite continued suppression of lipid peroxidation, only DFO maintained significant cytoprotection against H(2)O(2), and this was accompanied by reduced DNA damage, higher ATP levels and preservation of cell proliferation. Thus, the inability of the lazaroid compound 2-MAC to sustain cytoprotection in the later stages of cell injury might provide at least a partial explanation for the inefficiency of lazaroids to limit tissue injury in clinical and certain in vivo settings.
 ...
PMID:Lazaroid compounds prevent early but not late stages of oxidant-induced cell injury: potential explanation for the lack of efficacy of lazaroids in clinical trials. 1120 66

HIV infection is associated with numerous abnormalities affecting both the myeloid and lymphoid lineages. We studied the features associated with peripheral cytopenias as the first sign of HIV infection in children. Peripheral blood (PB) counts, PB and bone marrow (BM) lymphocyte subsets, as well as viral load and serum levels of ferritin, vitamin B12, and folic acid were determined. Five children were naive of treatment (Group 1) and three were under HAART (Group 2). In Group 1 all patients had anemia of chronic disease. One had a bone marrow culture positive for Mycobacterium avium intracellulare and pancytopenia. Besides this, neutropenia and thrombocytopenia were seen in one patient each. In Group 2 anemia was found in all, neutropenia in one, and thrombocytopenia in two patients. Peripheral blood cytopenias were due to HAART toxicity in one patient. In the other two they were due to iron or folate deficiency. Bone marrow cytology showed cell abnormalities mainly in granulocytic precursors and megakaryocytes. All except two (taking HAART) patients had a high viral load. There was a straight correlation between viral load in PB and bone marrow. Viral load was correlated with peripheral CD4 but not with CD8 lymphocytes. A decrease in bone marrow B lymphocytes was seen in all patients. The introduction of HAART improved peripheral cytopenias. Bone marrow examination was useful for determining the etiology of the cytopenias and for detection of opportunistic infection. Hemopoietic cell abnormalities were similar to those seen in adults and indicative of HIV infection.
 ...
PMID:Bone marrow features in children with HIV infection and peripheral blood cytopenias. 1584 Jul 62


1 2 Next >>