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Biomedical subjects

R F Kampschmidt

Publications and source records attributed to R F Kampschmidt.

At least 19 recordsLinked to original sources
PubMed1986

Release of interleukin-1 (IL-1) and IL-1-like factors from rabbit macrophages with silica.

Oil-elicited rabbit macrophages stimulated by endotoxin were found to release increased amounts of interleukin 1 (IL-1) when incubated with silica. The assays used to determine the amount of IL-1 released were uptake of thymidine by mouse thymocytes, fever in rabbits, and neutrophilia in rats. All three assays showed that endotoxin-stimulated macrophages released five to 10 times more IL-1 when incubated with silica. Most of the IL-1 had a molecular weight (MW) of about 14,000 with a smaller amount at a MW of approximately 35,000. All of the neutrophilia-producing activity had an isoelectric point (pl) near 7. Thymocyte proliferation was promoted about equally by activities near pH 5 and 7. Fever was found not only at these two isoelectric points but also at a pl above 8 which had neither of the other two activities.

Animals↗
PubMed1985

Interleukin-1 from P388D1: effects upon neutrophils, plasma iron, and fibrinogen in rats, mice, and rabbits.

Partially purified interleukin-1 was prepared from the murine cell line P388D1. This interleukin-1 produced fever in rabbits and the amount required to cause an increase of 1 degree C was determined. This dose of interleukin-1 produced neutrophilia when injected into rats and rabbits but not in mice, and increased plasma iron and fibrinogen in all three species. Although the mouse was a poor responder to murine interleukin-1 for neutrophilia, it responded unusually well for increasing plasma fibrinogen.

Animals↗
PubMed1985

Rate of clearance of interleukin-1 from the blood of normal and nephrectomized rats.

Interleukin-1 (IL-1), a macrophage product, appears to be responsible for a wide variety of changes in animals during the early stages of infection and inflammation. However, the fate of injected IL-1 has not been established. The major pathway of removal from the circulation may be through the kidney, since IL-1 can be found in urine. The IL-1 for these studies was prepared from peritoneal macrophages of rats and rabbits. The clearance rate of IL-1 was determined by measuring the activity, for increasing plasma fibrinogen or releasing bone marrow neutrophils, which remained in the blood at various times after an iv injection. Both rat and rabbit IL-1 were removed rapidly from the blood of rats. The results indicate that less than 10% of the IL-1 was cleared by the kidney. So that rats with their kidneys removed showed only a slight decrease in the clearance rate of IL-1. This suggests that excretion through the kidney does not represent the major mechanism of IL-1 disposal.

Animals↗
PubMed1983

Further comparisons of endogenous pyrogens and leukocytic endogenous mediators.

It was recently shown (Murphy et al., Infect. Immun. 34:177-183), that rabbit macrophages produce two biochemically and immunologically distinct endogenous pyrogens. One of these has or copurifies with substances having a molecular weight of 13,000 and a pI of 7.3. This protein was produced by blood monocytes or inflammatory cells elicited in 16-h rabbit peritoneal exudates. These acute peritoneal exudates were produced by the intraperitoneal injection of large volumes of saline containing shellfish glycogen. When the leukocytes in these exudates were washed and incubated at 37 degrees C in saline, they released an endogenous pyrogen. The injection of this pyrogen into rabbits, rats, or mice caused the biological manifestations which have been attributed to leukocytic endogenous mediator. These effects were increases in blood neutrophils, the lowering of plasma iron and zinc levels, and the increased synthesis of the acute-phase proteins. The other rabbit endogenous pyrogen seems to be a family of proteins with isoelectric points between 4.5 and 5.0. These proteins are produced by macrophages in the lung, liver, or in chronic peritoneal exudates. In these experiments, the lower-isoelectric-point endogenous pyrogens were produced by macrophages from the peritoneal cavity of rabbits that had been injected 4 days earlier with 50 ml of light mineral oil. These rabbit pyrogens were found to have leukocytic endogenous mediator activity in mice but to be completely inactive in rats. When injected into rabbits, these proteins produced fever, lowered plasma iron, increased blood neutrophils, but failed to elevate plasma fibrinogen.

Animals↗
PubMed1982

Characterization of a leukocyte-derived endogenous mediator responsible for increased plasma fibrinogen.

Fibrinogen has been the plasma protein most frequently studied after tissue injury. This report presents evidence that leukocytic endogenous mediator (LEM) from macrophages promotes fibrinogen synthesis. LEM has a molecular weight of 13,000-16,000, an isoelectric point (pI) at pH 7.3, is heat labile, and is inactivated by trypsin or sulfhydryl reactive agents. LEM not only promotes increased synthesis of acute phase proteins, but also causes increased neutrophilia and alterations in metal metabolism. There is considerable evidence that LEM may be the same protein as endogenous pyrogen and Interleukin 1 (IL-1). There was no increase in plasma fibrinogen when endotoxin was injected in C3H/HeJ mice; however, this strain of mice responded the same as normal mice to injections of LEM. This provides further evidence that LEM is the endogenous mediator for acute phase protein synthesis during tissue injury. The half-life of LEM is still circulation following its iv injection into rats was less than 10 minutes. There is still considerable doubt about the mechanism LEM uses in promoting increased hepatocyte synthesis of fibrinogen. Some evidence indicates a direct action of LEM upon the hepatocyte, whereas other data suggest an indirect role through other mediators or the central nervous system. In addition to LEM with pI of 7.3, there are proteins with a pI near 5 that will increase plasma fibrinogen. These proteins also have a molecular weight between 13,000 to 16,000 but do not have essential sulfhydryl groups. These proteins also have pyrogenic and IL-1 activities. LEM shows a limited amount of species specificity. For example, the pI 7 LEM prepared from human monocytes or rabbit peritoneal leukocytes will increase plasma fibrinogen in rats, mice, and rabbits; but the pI 5 LEM from rabbits is inactive in rats.

Animals↗
PubMed1980

The activity of partially purified leukocytic endogenous mediator in endotoxin-resistant C3H/HeJ mice.

Partially purified LEM was injected into both the endotoxin-resistant C3H/HeJ and the closely related, but endotoxin-responsive, C3Heb/FeJ strains of mice. Both strains of mice responded to LEM with significant decreases in plasma iron concentration, increased number of peripheral blood neutrophils, increased plasma levels of CSA, and elevations of plasma fibrinogen concentration. Injections of endotoxin produced significant responses in these four determinations in C3Heb/FeJ mice but had no effect in the C3H/HeJ strain. Changes in plasma iron, fibrinogen, CSA, and neutrophils are believed to occur when LEM is produced by an interaction of endotoxin with phagocytic cells.

Animals↗
PubMed1978

Further similarities of endogenous pyrogen and leukocytic endogenous mediator.

The release of endogenous pyrogen (EP) from rabbit peritoneal granulocytes was measured with a three-point log dose-response curve. Release of EP was inhibited when the cells were incubated in media containing potassium or calcium. Measurements of leukocytic endogenous mediator (LEM) activity, i.e., lowering of plasma iron and zinc and increases in blood neutrophils, were made on the same supernatant media. When EP release was inhibited there was a similar inhibition of LEM activity. These results indicate a similarity between the release of pyrogenic and LEM activities. Together with previous purification studies, the results suggest that EP and LEM are similar and may be identical factors.

Animals↗