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Biomedical subjects

T Decker

Publications and source records attributed to T Decker.

118 records · Page 7Linked to original sources
PubMed1986

Functional heterogeneity of murine macrophage precursor cells from spleen and bone marrow.

We previously reported that highly purified bone marrow-derived macrophage precursors can exert strong spontaneous cytotoxicity against YAC-1 tumor cells, Candida albicans, and protozoa of the genus Leishmania. In the present paper, evidence is shown that macrophage precursors in normal untreated mice are not confined to the bone marrow compartment but can also be found in the spleen. These organ-associated cells, which have the same buoyant density as large granular lymphocytes, have been positively sorted by means of an indirect rosetting technique employing the macrophage-specific monoclonal antibodies F4/80 and M143. The rosetting fractions represented an extremely homogeneous population of macrophage precursors characterized by high candidacidal and natural killer activity and by a strong proliferative response to the macrophage-specific colony-stimulating factor CSF-1. Spleen- and bone marrow-derived macrophage precursors differed in their target selectivity. In addition, the mature macrophages derived in vitro from these two precursor populations displayed striking differences in their candidacidal activity. The implications of these findings in relationship to heterogeneity in the macrophage differentiation line are discussed.

Animals↗
PubMed1986

[CT diagnosis of focal nodular hyperplasia].

The paper analyses the findings of a CT study of 21 lesions of focal nodular hyperplasia in 17 patients. In addition to subjective valuatin of the dynamic studies, densitometric measurements on a time basis were carried out (gamma-fit curves) and a density profile was obtained. These tumour-like lesions show typical density changes with rapid enhancement in the arterial phase and rapid fall in density after one or two minutes. Various patterns of the hyperdense lesions (non-homogeneous, those resembling vessels or homogeneous lesions) may be of significance in differential diagnosis. Atypical density patterns were found particularly in foci projecting from the liver.

Adolescent↗
PubMed1986

Heterogeneous activity of immature and mature cells of the murine monocyte-macrophage lineage derived from different anatomical districts against yeast-phase Candida albicans.

Mature mononuclear phagocytes have been receiving much attention as effectors of spontaneous candidacidal activity, although with controversial results due to differences in the effector populations and the methods used in different laboratories. We here systematically compare the fungistatic activity of immature and mature cells of the murine macrophage series. The results show that nonadherent, nonphagocytic precursor cells (isolated either [90% purity] from bone marrow liquid cultures or from the organs of mice in which inflammatory conditions had been elicited in vivo) exerted a strong extracellular candidastatic activity. In contrast, mature macrophages, either obtained from different anatomical areas (spleen, liver, lung, peritoneal cavity) or matured in vitro from the precursor populations, displayed striking heterogeneity in their ability to inhibit the growth of Candida albicans, depending on the anatomical site they were derived from. Lymphokine activation did not alter the fungistatic pattern of the untreated cells. The different macrophage populations behaved very differently also in the production of reactive oxygen intermediates (ROI) in response to phagocytosis of C. albicans. The amounts of ROI generated, however, showed no correlation with candidastatic ability. Low levels of candidastatic activity exerted by resident peritoneal macrophages (good ROI producers) were inhibited by catalase, whereas high levels of growth inhibition by Kupffer cells (poor ROI producers) after 8 h of assay were hardly influenced by the enzyme. Our data suggest the existence of two different effector mechanisms in macrophage-mediated C. albicans growth inhibition, a rather inefficient ROI-dependent one, and a second, very efficient oxygen-independent mechanism. The implications of these findings are discussed.

Animals↗
PubMed1986

[Delta virus superinfection in a patient with chronic viral hepatitis B].

Hepatitis-Delta virus is a defective RNA virus enclosing the Delta antigen and genome within a coat of hepatitis B surface antigen (HBsAg). Prevalence of Delta virus is limited to individuals with hepatitis B infection. Two modes of infection have been identified: coinfection with hepatitis virus B of healthy individuals and superinfection of HBsAg carriers. In a prospective study of 485 liver biopsies from HBsAg seropositive patients, 320 non-replicative HBsAg carriers (without evidence of core antigen) were discovered. In only one of these cases could a Delta virus superinfection be confirmed by immunohistology. It caused a shift from a preexisting chronic persistent to a chronic active hepatitis. This is the first case of chronic Delta virus infection confirmed by immunhistology in the G.D.R.

Adult↗
PubMed1985

Liver macrophages (Kupffer cells) as cytotoxic effector cells in extracellular and intracellular cytotoxicity.

The potential of the resident murine Kupffer cell to be cytotoxic in extra- and intracellular killing systems in vitro was investigated. Kupffer cells exerted no spontaneous cytotoxicity but were readily susceptible to activation with lymphokines. Such activated Kupffer cells very efficiently killed extracellular P815 cells and intracellular Leishmania spp. parasites. Kupffer cells could be induced to proliferate in vitro under the influence of colony-stimulating factor (D.-M. Chen, H.-S. Lin, P. Stahl, and R. Stanley, Exp. Cell Res. 121:103-109, 1979). Kupffer cell-derived macrophages cultured in vitro were identical to their liver-derived progenitors in terms of macrophage-specific surface antigens and with respect to extra- and intracellular cytotoxicity. These results demonstrated that Kupffer cells have a strong self-renewing potential and that essential Kupffer cell properties like antigenic determinants and cytotoxic potential remained stable throughout the replicative process. The possibility of Kupffer cell self-renewal in the intact organism is also discussed.

Animals↗
PubMed1985

[Immunohistological determination of beta-endorphin in chromophobe, clinically hormone-nonproducing hypophyseal adenomas].

Pituitary adenomas are usually classified according to the nature of their proper hormonal production. Silent adenomas of the pituitary are tumors without clinical and biochemical evidence of overproduction of any known adenohypophyseal hormones. The proportion of such seemingly nonfunctioning tumors is 20 to 30%. Silent corticotropic adenomas are able to synthesize some normal or abnormal sequences of proopiomelanocortin precursor without any signs of hypercorticism. These tumors were divided into basophilic adenomas with strong periodic acid-Schiff (PAS) positivity and chromophobic adenomas with moderate or no PAS positivity. All of our cases were chromophobic adenomas. Two of the cases were positive for beta-endorphin by immunofluorescence. ACTH immunoreactivity was not present in the cells. Electron microscopic study of the adenoma cells showed small secretory granules with a halo. The diameter of these granules varied from 50 to 250 nm. Automated morphometric and densitometric investigations of silent corticotropic adenomas and adenomas from patients with Cushing's disease gave different karyometric results. The most important practical problem arising from the present investigation was the high frequency of recurrence of silent corticotropic tumors.

Adenoma, Chromophobe↗
PubMedDate not supplied

Upper extremity weight-training modifications for the injured athlete. A clinical perspective.

The ability of the health care professional to make correct decisions about the progression of weight-training is critical to the rehabilitation process. The purpose of this article is to describe our approach to modification of weight-lifting techniques using the injured shoulder as a model. Additionally, the impact of various upper extremity weight-training techniques on healthy athletes is discussed. The effects of grip, hand spacing, bar trajectory, and start and finishing positions on microtraumatic injury and return to weight-training activities after injury are considered. Several weight-training functional progressions for common multijoint exercises (such as bench press, shoulder press, power clean) are presented. Adaptations for periodization are also presented for implementation in the rehabilitation sequence. The weight-training modifications described in this paper will assist the health professional to safely return athletes to the weight room after shoulder injury.

Adaptation, Physiological↗