Search results for "Histology"

Analysis of the axial filament in spicules of the demosponge Geodia cydonium: different silicatein composition in microscleres (asters) and megascler…

2007

The skeleton of the siliceous sponges (Porifera: Hexactinellida and Demospongiae) is supported by spicules composed of bio-silica. In the axial canals of megascleres, harboring the axial filaments, three isoforms of the enzyme silicatein (-alpha, -beta and -gamma) have been identified until now, using the demosponges Tethya aurantium and Suberites domuncula. Here we describe the composition of the proteinaceous components of the axial filament from small spicules, the microscleres, in the demosponge Geodia cydonium that possesses megascleres and microscleres. The morphology of the different spicule types is described. Also in G. cydonium the synthesis of the spicules starts intracellularly …

Overexpression of TGF-ß1 in macrophages reduces and stabilizes atherosclerotic plaques in ApoE-deficient mice.

2011

Although macrophages represent the hallmark of both human and murine atherosclerotic lesions and have been shown to express TGF-ß1 (transforming growth factor β1) and its receptors, it has so far not been experimentally addressed whether the pleiotropic cytokine TGF-ß1 may influence atherogenesis by a macrophage specific mechanism. We developed transgenic mice with macrophage specific TGF-ß1 overexpression, crossed the transgenics to the atherosclerotic ApoE (apolipoprotein E) knock-out strain and quantitatively analyzed both atherosclerotic lesion development and composition of the resulting double mutants. Compared with control ApoE(-/-) mice, animals with macrophage specific TGF-ß1 overe…

TGF-β Suppresses Tumor Progression in Colon Cancer by Inhibition of IL-6 trans-Signaling

2004

Alterations of TGF-beta signaling have been described in colorectal cancer, although the molecular consequences are largely unknown. By using transgenic mice overexpressing TGF-beta or a dominant-negative TGF-betaRII, we demonstrate that TGF-beta signaling in tumor infiltrating T lymphocytes controls the growth of dysplastic epithelial cells in experimental colorectal cancer, as determined by histology and a novel system for high-resolution chromoendoscopy. At the molecular level, TGF-beta signaling in T cells regulated STAT-3 activation in tumor cells via IL-6. IL-6 signaling required tumor cell-derived soluble IL-6R rather than membrane bound IL-6R and suppression of such TGF-beta-depende…

Cdc42 in osterix-expressing cells alters osteoblast behavior and myeloid lineage commitment

2021

Osteoblasts are not only responsible for bone formation. They also support hematopoiesis. This requires responding to cues originating from several signaling pathways, a task performed by Rho GTPases. We therefore examined several transgenic mouse models and used inhibitors of Cdc42 in vitro. Deletion of Cdc42 in vivo using the Osterix promoter suppressed osteoblast function, while its deletion in differentiating osteoblasts using the Collagen-a1(I) promoter decreased osteoblast numbers. In both cases, bone mineral density diminished confirming the importance of Cdc42. Evaluation of hematopoiesis revealed that deletion of Cdc42 using the Osterix, but not the Collagen-a1(I) promoter increase…

Scanning electron microscopy of heterochromatin in chromosome spreads of male germ cells in Schistocerca gregaria (Acrididae, Orthoptera) after tryps…

1996

Chromosome spreads, prepared from testes of the desert locust Schistocerca gregaria, were analyzed using scanning electron microscopy (SEM) after varying periods of preincubation in trypsin. The emphasis of the study was on the appearance of heterochromatin. A trypsin pretreatment of 5 sec resulted in a smooth surface on the chromatin throughout and the heterochromatin was highly electron-emissive. The facultatively heterochromatic X chromosome was clearly visible in interphase spermatogonia and in pachytene and late prophase I spermatocytes. Chromomeres of autosomal bivalents could be recognized in pachytene cells. Centromeric heterochromatin segments were very prominent in autosomes of la…

Bacteria associated with winter mortalities in laboratory-reared common dentex (Dentex dentex L.)

2007

A pathological study was conducted on laboratory-reared juvenile common dentex (Dentex dentex) suffering trickling and continuous mortalities. During a 3-month period (October-December), water temperature, clinical signs and mortalities were recorded. Moribund or dead fish were examined for bacteria and parasites. Bacteria were isolated from head kidney and external ulcers, and samples from the gills, intestine, stomach, trunk kidney, gall bladder and liver were taken for histology. Cumulative mortality reached 73%, and 80% of fish examined were positive for bacteria (102 isolates). Vibrio splendidus was the most prevalent in head kidney (59.7%) and ulcers (88.9%), and it was frequently iso…

Protective role of the complement regulatory protein human CD-55 in cardiac xenograft: a descriptive study and a revision of the literature.

2002

The limited and inadequate availability of organs from human donors has resulted in the utilisation of xenografts as an alternative tool. Nevertheless, hyperacute rejection (HAR) following xenograft determines the loss of the transplanted organ. The “primum movens” is the activation of the complement pathway mediated by the binding of natural xenogenic antibodies to the endothelium of the graft, followed by the lysis of the endothelial cells with subsequent oedema, thrombosis and necrosis of the transplanted organ. In this work we describe morphological and biomolecular observations of isolated human-decay accelerating factor (h-DAF, CD55) transgenic pig hearts, after perfusion for four hou…

Uterine rejection after allogeneic uterus transplantation in the rat is effectively suppressed by tacrolimus

2013

Objective To evaluate the effects of the immunosuppressant tacrolimus on rejection of a transplanted uterus and on uterine expression of markers of inflammation and implantation. Design Experimental study. Setting University laboratory. Animal(s) Female rats. Intervention(s) Uteri from brown Norway rats were transplanted to Lewis rats, receiving either tacrolimus or no treatment. Sham groups underwent either hemihysterectomy or tacrolimus treatment. Main Outcome Measure(s) Gross morphology, histology, density of T-lymphocytes by immunohistochemistry, and mRNA levels of interleukin (IL)-1α, leukemia inhibitory factor (LIF), galectin-1, CD200, IL-15, interferon-inducible protein-10 (IP-10), a…

Extramammary Paget's disease arising in a mature cystic teratoma of the ovary.

1999

Electric organ ofGnathonemus (Mormyridae)

1971

1. Die drei Arten der GattungGnathonemus (Gn. petersii, moorii, stanleyanus) besitzen, wie alle Arten der Familie Mormyridae, zwei Paar elektrische Organe, die symmetrisch auf jeder Seite der Wirbelsaule zwischen der Caudal-, Dorsal- und Afterflosse liegen. Jedes Organ ist aus einer Serie von 70–170 elektrischen Platten zusammengesetzt. 2. Die Stiele der elektrischen Platten enthalten keine Nervenfortsatze. Die elektromotorischen Nervenfasern innervieren die Endanschwellung der Stiele, indem sie sich unverzweigt in einem kurzen marklosen Endabschnitt in eine Vertiefung des Elektroplasmas einfugen. 3. Die Elektroplasmamembran umgibt ohne Ausnahme die Stiele und die elektrische Platte. Sie is…