On the phylogeny of splenic structure and function

Pitchappan, R. M.

doi:10.1016/s0145-305x(80)80044-9

Cited by 28 publications

(13 citation statements)

References 53 publications

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“…Lamers (1986) reported that the pyroninophilic cell clusters were found around the MMC in spleen and trunk kidney of carp, Cyprinus carpio; however, such cell clusters have never been encountered in the MMC in the hemopoietic tissues of the sea horse kidney. It should be noticed that all poikilotherms lack germinal centers, and fish in particular have a poorly developed white pulp (Good et al, 1966;Pitchappan, 1980). The histologic pictures of the MMC and surrounding tissues seen after injection of antigenic AF were almost the same as those of controls or those injected with nonantigenic CP.…”

Section: Discussionmentioning

confidence: 93%

Melano‐macrophage centers in the aglomerular kidney of the sea horse (Teleosts): Morphologic studies on its formation and possible function

Tsujii

Seno

1990

Anat. Rec.

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In order to elucidate the process of the formation and possible function of the renal "melano-macrophage centers (MMC)" of fish, light and electron microscopic observations were carried out on the aglomerular kidney of the sea horse, Hippocampus kuda BLEEKER, injected with antigenic horse-spleen ferritin (AF) and nonantigenic carbon particles (CP). Kidneys of the sea horse have well-developed hemopoietic foci in the interstitial tissues surrounding the bundles of renal tubules. Each hemopoietic focus has a small artery in the central area and is framed with the densely arranged sinusoids lined with monolayered macrophages which have no melanin pigments. In the hemopoietic foci free macrophages (M phi) were hardly found, but large clusters of MMC filled with densely packed masses of cell debris with some melanin pigments were encountered. Some of them had degenerated M phi with fibrotic change surrounded by fibroblasts. AF and CP injected intraperitoneally entered quickly into blood vessels and were taken up actively by the sinusoidal M phi. The M phi full of AF or CP left the sinusoidal wall and moved gradually into hemopoietic foci to form the MMC or to fuse with the preexisting MMC. The melanophores in the interstitial connective tissue joined to form the MMC. No specific histologic change suggestive of immune response to the AF was present in and around the MMC. The results indicate that the MMC of fish should be only the aggregates of M phi to digest the ingested materials effectively. The process of formation of MMC and their possible function is discussed.

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Section: Discussionmentioning

confidence: 93%

Melano‐macrophage centers in the aglomerular kidney of the sea horse (Teleosts): Morphologic studies on its formation and possible function

Tsujii

Seno

1990

Anat. Rec.

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“…Lymphocytes probably appeared later. Pitchappan (2) suggested that sequential additions during the evolution of the spleen amongst different species were: (1) lymphocyte accumulation surrounding major arteries, (2) appearance of white pulp follicles, (3) the dependence of the periarteriolar region on the thymus, and (4) germinal centres. For each of these structures, there has been progressive development during evolution.…”

Section: Introductionmentioning

confidence: 99%

“…A number of questions remain unanswered: (1) when and where do spleen mesenchymal progenitors appear to be specified within the developing embryo? (2) are interactions between the mesenchyme and the epithelial-like mesothelial layer that lines the developing spleen critical for spleen morphogenesis? (3) which transcription factors and signaling molecules activate spleen-specific genetic programs?…”

Section: Introductionmentioning

confidence: 99%

Development and function of the mammalian spleen

et al. 2007

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The vertebrate spleen has important functions in immunity and haematopoiesis, many of which have been well studied. In contrast, we know much less about the mechanisms governing its early embryonic development. However, as a result of work over the past decade-mostly using knockout mice--significant progress has been made in unravelling the genetic processes governing the spleen's early development. Key genetic regulators, such as Tlx1 and Pbx1, have been identified, and we know some of the early transcriptional hierarchies that control the early patterning and proliferation of the splenic primordium. In mouse and humans, asplenia can arise as a result of laterality defects, or the spleen can be absent with no other discernible abnormalities. Surprisingly, given the spleen's diverse functions, asplenic individuals suffer no major haematopoietic or immune defects apart from a susceptibility to infection with encapsulated bacteria. Recent evidence has shed light on a previously unknown role of the spleen in the development and maintenance of specific B cell populations that are involved in the initial response to infection caused by encapsulated bacteria. The lack of these populations in asplenic mice and humans may go some way to explaining this susceptibility.

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“…The lymphoid system of vertebrates is organized into the central and peripheral lymphoid organs (Cohen, 1976). Among the latter, the spleen is present in all jawed vertebrates (Pitchappan, 1980). The spleen of dipnoans is embedded in the intestinal wall while in other fish and tetrapods it is a separate organ hanging in the mesentery near the intestine (for review see Zapata, 1983;Fange & Nilsson, 1985;Tischendorf, 1985).…”

Section: Introductionmentioning

confidence: 99%

“…The spleen of most vertebrates usually contains white and red pulp. However, the development of these two parts differs considerably among vertebrates (for review see Pitchappan, 1980). In this context the anuran amphibians seem very interesting as in this order of animals there are species which differ drastically in the degree of the development of the white pulp (Diener & Nossal, 1966;Cooper & Wright, 1976;Manning & Horton, 1982;Barrutia et al, 1983;Plytycz & Bigaj, 1983).…”

Section: Introductionmentioning

confidence: 99%