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R van Furth

Publications and source records attributed to R van Furth.

At least 379 records · Page 21Linked to original sources
PubMed1972

The mononuclear phagocyte system: a new classification of macrophages, monocytes, and their precursor cells.

There have been many attempts in the past to classify phagocytic mononuclear cells and to define the cell system they are considered to form-among these being the "macrophage system" of Metchnikoff, the "reticulo-endothelial system" of Aschoff, and the "reticulo-histiocyte system" proposed by Volterra and reintroduced by Thomas. None of these is entirely adequate in the light of present knowledge. In 1969, therefore, a group of workers proposed a new classification of all highly phagocytic mononuclear cells and their precursors in what they termed the "mononuclear phagocyte system". This system includes the promonocytes and their precursors in the bone marrow, the monocytes in the peripheral blood, and the macrophages in the tissues. Subsequent consultation with numerous other specialists throughout the world led to a certain number of changes in this classification, which is now proposed in revised form.Inclusion of cells in the "mononuclear phagocyte system" is based on similarities in the morphology, function, origin, and kinetics of the phagocytes. By these criteria reticular cells, dendritic cells, endothelial cells, and fibroblasts (fibrocytes) are excluded. The proponents point out that as new knowledge is acquired modifications may have to be made, certain cells being added to or removed from the new classification.

Bone Marrow Cells↗
PubMed1970

Morphology and peroxidase cytochemistry of mouse promonocytes, monocytes, and macrophages.

Mouse promonocytes have been identified and studied in cultures of bone marrow cells. These cells have a diameter of 14-20 micro, and in stained preparations reveal a large, indented or folded nucleus, and basophilic, finely granular cytoplasm. The living promonocyte viewed by phase contrast shows additional features: nucleoli, small dense bodies, and vesicles in the cytoplasm adjacent to the nuclear hilus, and slight membrane ruffling. Prominent ultrastructural components of promonocytes include a well developed Golgi apparatus, small numbers of centrosomal granules and vacuoles, extensive ribosomal aggregates, and finger-like projections of the cell surface. Promonocytes engage in pinocytosis and phagocytosis, but they are less active in these functions than are peripheral blood monocytes of peritoneal macrophages. Promonocytes are positive for peroxidase, the reaction product being localized to granules most of which are centrally situated in the cell. Monocytes in blood or in inflammatory peritoneal exudates display much smaller numbers of peroxidase-positive granules, and various types of mature mouse macrophages are peroxidase negative.

Animals↗
PubMed1970

The kinetics of promonocytes and monocytes in the bone marrow.

The mononuclear phagocytes of the bone marrow can be classified into two cell types, promonocytes and monocytes. The present study was performed to establish whether the promonocytes are the progenitors of the monocytes and to determine the kinetic characteristics of the promonocytes and monocytes in the bone marrow compartment. Both in vitro labeling studies with thymidine-(3)H and determination of the relative amount of DNA in the nuclei of individual cells showed that under normal steady-state conditions the promonocytes are proliferating cells and the monocytes, nondividing cells. In vivo labeling studies provided further evidence that the promonocytes are the progenitor cells of the monocytes. During the first 24 hr after labeling, the promonocytes showed a constant high level of labeling (about 70%). The mean grain count of these cells decreased with time. The labeling index of the monocytes of the bone marrow increased during the first 24 hr after in vivo labeling, but during the same period the mean grain counts remained almost constant, with values amounting to about half those of the promonocytes during the first 6 hr of the experiment. The data concerning the labeling indices and the percentage distribution ratio of the promonocytes and monocytes in the bone marrow, and the labeling indices of the peripheral blood monocytes are used to construct a model population. The results lead to the conclusions that the promonocytes are multiplicative cells and that both daughter cells arising from the division of a promonocyte are monocytes. The DNA-synthesis time found for the promonocytes is 13.6 hr. From this value, the average generation time was computed to be 19.5 hr.

Animals↗
PubMed1970

The effect of glucocorticosteroids on the kinetics of mononuclear phagocytes.

The effect of glucocorticosteroids on the kinetics of mononuclear phagocytes, i.e., peripheral blood monocytes and peritoneal macrophages, was studied in normal mice, as well as in mice in which an inflammatory reaction was evoked in the peritoneal cavity. The administration of glucocorticosteroids resulted in a rapid decrease (within 3-6 hr) in the number of circulating monocytes, the duration being dependent on the nature and dose of the compound. The water-soluble dexamethasone sodium phosphate is only briefly active (less than 12 hr), but hydrocortisone acetate, which forms a subcutaneous depot, reduced the number of monocytes for more than 2 wk. In normal mice, hydrocortisone did not affect the number of macrophages already present in the peritoneal cavity, but the transit of mononuclear phagocytes from the circulation into the peritoneal cavity was arrested. During an inflammatory response in the peritoneal cavity, hydrocortisone suppresses both the increase in the number of monocytes in the peripheral blood and the increase in the number of peritoneal macrophages. This reduction of the inflammatory exudate appeared to be due to a diminished influx of mononuclear phagocytes from the peripheral blood. No lytic action of glucocorticosteroids on the mononuclear phagocytes could be demonstrated.

Animals↗
PubMed1968

The origin and kinetics of mononuclear phagocytes.

The origin and turnover of efferent populations of mouse mononuclear phagocytes has been described. Mononuclear phagocytes were defined as mononuclear cells which are able to adhere to glass and phagocytize. In vitro labeling studies with thymidine-(3)H showed that monocytes in the peripheral blood and peritoneal macrophages do not multiply and can be considered end cells in a normal, steady state situation. However, the mononuclear phagocytes of the bone marrow appear to be rapidly dividing cells. This conclusion was supported by in vivo labeling experiments. A peak of labeled mononuclear phagocytes of the bone marrow was found 24 hr after a pulse of thymidine-(3)H. This was followed, 24 hr later, by a peak of labeled monocytes in the peripheral blood. From these experiments it was concluded that the rapidly dividing mononuclear phagocytes of the bone marrow, called promonocytes, are the progenitor cells of the monocytes. Labeling studies after splenectomy and after X-irradiation excluded other organs as a major source of the monocytes. Peak labeling of both the blood monocyte and peritoneal macrophages occurred at the same time. A rapid entry of monocytes from the blood into the peritoneal cavity was observed, after a sterile inflammation was evoked by an injection of newborn calf serum. These data have led to the conclusion that monocytes give rise to peritoneal macrophages. No indications have been obtained that mononuclear phagocytes originate from lymphocytes. In the normal steady state the monocytes leave the circulation by a random process, with a half-time of 22 hr. The average blood transit time of the monocytes has been calculated to be 32 hr. The turnover rate of peritoneal macrophages was low and estimated at about 0.1% per hour. On the basis of these studies the life history of mouse mononuclear phagocytes was formulated to be: promonocytes in the bone marrow, --> monocytes in the peripheral blood, --> macrophages in the tissue.

Animals↗