Biomedical subjects

D J Cameron

Publications and source records attributed to D J Cameron.

At least 55 records · Page 3Linked to original sources

PubMed1984

Ability of cancer patients' macrophages to kill autologous tumor targets. Effect of prostaglandin inhibitors on cytotoxicity.

Monocyte-derived macrophages isolated from the peripheral blood of 17 patients with cancer were studied for their cytotoxic effects on a sensitive allogeneic tumor target as well as autologous tumor cells. Macrophages from four of the cancer patients were cytotoxic towards the allogeneic tumor target. Five patients had macrophages which were cytotoxic towards the autologous targets. When indomethacin, a prostaglandin inhibitor, was added to the noncytotoxic macrophages during the cytotoxicity assay, macrophages from 5 of the 11 cancer patients studied became cytotoxic for the allogeneic target, and macrophages from 4 of the 11 patients became cytotoxic for the autologous tumor cells. However, it was also noted that those cancer patients who possessed cytotoxic macrophaged in the absence of indomethacin, became noncytotoxic towards the tumor cells after addition of indomethacin. These results indicate that addition of indomethacin to cytotoxic macrophages suppresses macrophage mediated cytotoxicity whereas addition of indomethacin to noncytotoxic macrophages greatly enhances macrophage mediated cytotoxicity. This theory was further substantiated when it was observed that the cytotoxic macrophages obtained from normal donors also became noncytotoxic for a sensitive tumor cell line after the addition of indomethacin during the cytotoxicity assay.

Cells, Cultured↗

PubMed1984

Separation of macrophages on discontinuous bovine serum albumin (BSA) density gradients: cytotoxic effects of fractionated cells from normal donors and cancer patients.

Human monocytes from normal donors as well as breast or colon cancer patients were fractionated on five-step discontinuous bovine serum albumin (BSA) density gradients, and the monocytes from each fraction were allowed to mature into macrophages during a 5 day incubation period. The macrophages were then examined both for their ability to kill tumor cells after activation with lipopolysaccharide (LPS) and the quantity of prostaglandin E2 (PGE2) synthesized. When the macrophages obtained from normal donors were fractionated, fractions 2 and 4 which comprised 58% of the total cell population, were cytotoxic for tumor cells. In contrast, when the macrophages from breast cancer patients were fractionated, only the high density cells found in fraction 4 were cytotoxic. It is also conceivable that since fraction 4 comprises only 26% of the total macrophages recovered, this may be the reason unfractionated macrophages from breast cancer patients are unable to kill tumor cells. When the colon cancer patients' macrophages were fractionated on BSA density gradients, fractions 1, 2 and 4, which comprised 79% of the total cell population, were cytotoxic for tumor cells. Prostaglandin E2 synthesis was also analyzed and it was found that fraction 3 consistently synthesized increased quantities of PGE2 when compared with the other three fractions. Furthermore, since fraction 3 was non-cytotoxic for tumor cells, it is conceivable that the increased synthesis of PGE2 by fraction 3 rendered these macrophages non-cytotoxic.

Animals↗

PubMed1984

Incidence and cumulative frequency of endemic Lyme disease in a community.

We conducted an epidemiological study of the cumulative frequency and incidence of Lyme disease in a summer community on Fire Island, New York, an area endemic for the disease. Fifteen (7.5%) of 200 persons studied in the community in 1982 reported a history of Lyme disease. An indirect immunofluorescent antibody assay showed that seventeen (9.7%) of 176 persons had serological evidence of exposure to the Lyme spirochete, including six of the 15 persons with a history of Lyme disease. Seven (0.7%-1.2%) of 600-1,000 persons in the community developed clinical symptoms and serological evidence of Lyme disease during the summer season, including two (1%) of the 200 persons in the study group. Four (3.1%) of 129 persons who had sera collected before and after the summer season demonstrated fourfold or greater rises in IgG antibody titers to the Lyme spirochete, including 2 (1.6%) persons without symptoms of Lyme disease. We conclude that the incidence of Lyme disease can be appreciably higher in endemic areas than previously recognized and that subclinical or inapparent seroconversion may occur after infection.

Adolescent↗

PubMed1984

Characterization of human macrophage activation factor (MAF) prepared from antigen-stimulated lymphocytes.

Macrophage activation factor (MAF) and migration inhibitory factor (MIF) obtained from sensitized human lymphocytes stimulated by streptokinase-streptodornase (SK-SD) were characterized by gel filtration and isoelectric focusing (IEF) techniques. Twenty-four and 48 hr supernatants were chromatographed on Sephadex G-100 columns and the eluate pooled into 5 fractions: the void volume (Fr. I), the eluate containing molecules with a molecular weight ranging from 55-70,000 (Fr. II), 30-55,000 (Fr. III), 20-30,000 (Fr. IV) and 10-20,000 (Fr. V). The 24 hr supernatants contained MIF activity in Fraction IV and maximal MAF activity in Fractions I and II whereas the 48 hr supernatants contained MIF activity in Fractions II and IV and maximal MAF activity in Fractions II and III. When the supernatants were purified by IEF, the eluant was pooled into 5 fractions: Fraction I (pI 3.5-4), Fraction II (pI 4-4.5), Fraction III (pI 4.5-5), Fraction IV (pI 5-5.5) and Fraction V (pI 5.5-6). The 24 hr supernatants contained maximal MIF activity in Fractions III and IV and maximal MAF activity in Fraction III whereas the 48 hr supernatants contained both maximal MIF and MAF activity in Fractions I and IV. Thus, it appears that although human MAF can be differentiated from MIF in the 24 hr supernatants, MAF and MIF activity in the 48 hr supernatants are generally found in the same fractions when examined either by IEF or gel filtration techniques.

Chromatography, Gel↗

PubMed1984

Cytotoxic effects of polymorphonuclear leukocytes and macrophages in patients undergoing lymph depletion via thoracic duct drainage.

It has been previously reported that both human peripheral blood monocyte derived macrophages and polymorphonuclear leukocytes acquire enhanced cytotoxicity for tumor cells. Lymphocyte depletion by thoracic duct cannulation prior to renal transplantation has been shown to suppress allograft rejection. However, the effects of thoracic duct drainage on macrophage and polymorphonuclear leukocyte function is not known. When the macrophages obtained from thoracic duct drainage patients were studied prior to cannulation, four of the five patients possessed cytotoxic macrophages. At 1 to 2 weeks post thoracic duct drainage, cytotoxicity was significantly depressed whereas by 3 weeks post thoracic duct cannulation most of the patients' macrophages exhibited maximal cytotoxicity. Approximately 3 1/2 weeks after cannulation these five patients received cadaveric renal transplants. The cytotoxic effects of the macrophages were tested again after transplantation and it was found that the macrophages became incapable of killing the tumor targets. In contrast to our findings with macrophage mediated cytotoxicity, the polymorphonuclear leukocytes generally retained their cytotoxic capabilities at all time points tested. However, it was noted that cytotoxic activity reached maximal levels within the first 3 weeks after cannulation but fell to low cytotoxic levels at approximately 4 to 5 weeks after cannulation. When tested several months post cannulation and transplantation, polymorphonuclear leukocyte mediated cytotoxicity increased dramatically in four of the five patients studied.

Adolescent↗

PubMed1984

Inhibition of macrophage mediated cytotoxicity by exogenous adenosine 5'-triphosphate.

Peripheral blood monocyte derived macrophages from normal donors can be activated with lipopoly-saccharide (LPS) to kill human tumor cells. However, if adenosine 5'-triphosphate (ATP) is added to the macrophage-tumor cell suspensions in micromolar concentrations (10-100 microM), there is marked inhibition of macrophage mediated cytotoxicity. The inhibitory activity was specific to ATP; as it was not demonstrated with GTP, UTP, CTP, AMP or ADP. In addition, this inhibitory activity resulted from an effect of ATP on the effector cells rather than the target cells. When the effector cells were preincubated with ATP they became incapable of killing the tumor cells whereas preincubation of the target cells with ATP had no effect on their ability to be killed by the macrophages. Cytotoxicity was also inhibited when 100 microM of ATP were added to the macrophage monolayers either at the time of addition of the tumor cells or 15-60 min after addition of the tumor cells whereas no inhibition of cytotoxicity occurred when ATP was added more than 1 hr after the initiation of the cytotoxic reaction.

Adenosine Triphosphate↗

PubMed1984

Biochemical purification of antineoplastic agents obtained from sturgeon serum.

Discontinuous and continuous DEAE-Sephadex ion-exchange gradients were utilized to purify two sturgeon serum factors (A2 and B2) that possessed cytotoxic activity in vitro against human tumor cells but not against normal cells. After rabbit antisturgeon factor A2 or B2 was prepared, the antibodies were insolubilized. Sturgeon serum then was adsorbed to the insolubilized antibodies, and factors A2 and B2 were isolated in quantities large enough to conduct biologic studies. When the two factors purified either by ion-exchange chromatography or immunoadsorbent columns were examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and isoelectric focusing, factor A2 consisted of one protein band with a molecular weight greater than 68,000 and an isoelectric point of approximately 6.5. Likewise, factor B2 also consisted of one protein band with a molecular weight in excess of 68,000 and an isoelectric point of approximately 7.5. Both factors A2 and B2 were destroyed either by heating at 56 degrees C for 30 minutes or by heating at 100 degrees C for 2 minutes. Furthermore, the mechanism of tumor killing by the sturgeon factors appears to be by means of a soluble factor. When the kinetics of tumor killing was studied, the sturgeon factors were noncytotoxic after 4 or 8 hours of incubation and became cytotoxic after 24 hours of incubation.

Animals↗

PubMed1983

Spirochetes isolated from the blood of two patients with Lyme disease.

We isolated spirochetes from the blood of 2 of 36 patients in Long Island and Westchester County, New York, who had signs and symptoms suggestive of Lyme disease. The spirochetes were morphologically similar and serologically identical to organisms recently found to infect lxodes dammini ticks, which are endemic to the area and have been epidemiologically implicated as vectors of Lyme disease. In both patients, there was a rise in specific antispirochetal antibodies in paired specimens of serum. We conclude that the l. dammini spirochete has an etiologic role in Lyme disease.

Adult↗

PubMed1983

Macrophage-mediated tumor cytotoxicity: role of macrophage surface sialic acid.

Cell surface sialic acid levels were compared for monocytes and macrophages obtained from normal volunteers and breast cancer patients. Equal quantities of sialic acid were found on the monocytes obtained from normal volunteers and breast cancer patients. Approximately 60% more cell surface sialic acid was found on the macrophages from breast cancer patients than was found on the macrophages from normal volunteers. In order to determine whether cell surface sialic acid had any effect on macrophage-mediated cytotoxicity, macrophages were pretreated with neuraminidase (NANAse) prior to co-cultivation with tumor cells. The normal macrophages, after neuraminidase treatment, no longer retained their ability to kill tumor cells. However, when macrophages from breast cancer patients were treated with NANAse, no difference was observed in the ability of untreated and NANAse treated macrophages to kill tumor cells.

Breast Neoplasms↗

PubMed1983

Characterization of the preformed antibodies involved in the xenograft reaction.

The dog-to-sheep renal xenograft model was utilized to isolate the antibodies that participate in xenograft hyperacute rejection. These sheep antibodies, which were isolated from the rejected dog kidney, agglutinated and killed only dog blood and kidney cells whereas the whole sheep serum reacted with both dog and rabbit cells. The purified antibody was also utilized to obtain in pure form the antigens involved in the hyperacute rejection. When this antigen was tested for its ability to bind the serum of various species, this particular antigen was highly specific for sheep serum and would not react with rabbit, horse, calf, or mouse sera.

Animals↗

PubMed1983

Antigen-coated immunoadsorbents utilized for in vivo depletion of antibodies and lymphocytes with specificity for the antigen.

Hyperacute rejection of xenografts is thought to be triggered by humoral antibodies. It is known that natural antibodies against dog blood cells have been identified in sheep serum. Dog kidney antigen immunoadsorbent columns were placed in the extracorporeal lymph circuit of two sheep. In vivo studies have shown that these immunoadsorbent columns were effective in depleting the thoracic duct lymph of all antibodies with specificity for the dog kidney antigen. However, these columns were not effective in depleting the thoracic duct lymphocytes bearing surface receptors for the dog kidney antigen. When in vitro studies were carried out, the immunoadsorbent columns were effective in the depletion of both lymphocytes and antibody for the dog kidney antigen. Thus, since a humoral antibody response is thought to be responsible for the hyperacute rejection seen in xenografts, it is possible that these columns might be effective in prolonging xenograft survival.

Adsorption↗

PubMed1983

A comparison of the cytotoxic potential in polymorphonuclear leukocytes obtained from normal donors and cancer patients.

Human polymorphonuclear leukocytes (PMNs) obtained from both normal donors and cancer patients kill human tumor cells in vitro. Furthermore, the PMNs were shown to exert a greater cytotoxic effect on malignant targets than they did on nonmalignant targets. In addition, colon and breast cancer patients with stage I disease were found to possess PMN cells which were less effective in killing the tumor cells than were the PMN cells from normal donors. In contrast, the colon and breast cancer patients with stage IV disease possessed PMN cells which were more effective than normal cells in killing the tumor targets. No clear cut trend was found for PMN cells obtained from breast and colon cancer patients diagnosed with stage II and III disease. However, it must also be noted that individual patients did not always conform to the group pattern.

Breast Neoplasms↗

PubMed1983

Inhibitory factors derived from human tumors: isolation of factors which suppress macrophage mediated cytotoxicity.

Previously, we had demonstrated that plasma inhibitory factors obtained from colon cancer patients suppressed macrophage mediated cytotoxicity. When this inhibitor was further purified, four fractions (A, B, C and D) with inhibitory activity were isolated. In this study, it was found that these four purified inhibitory factors also dramatically decreased the extent of macrophage mediated cytotoxicity induced by LPS when added during the activation phase of the assay. When the secretions from a variety of fresh tumors as well as several established tumor cell lines were purified utilizing immunoadsorbent techniques, those same inhibitory factors were recovered. It was found that 8 of the 11 secretions obtained from a variety of fresh tumors and established tumor cell lines secreted inhibitor A; 6 secreted inhibitor B and 5 secreted inhibitor C. (The presence of inhibitor D was not studied.) Furthermore, one of the 11 tumors studied secreted none of these inhibitory factors. These findings lend support to the theory that these inhibitory factors which are initially produced by the tumor and subsequently shed into the sera ultimately lead to in vivo suppression of macrophage mediated cytotoxicity.

Ascitic Fluid↗

PubMed1983

Isolation and characterization of anti-neoplastic sturgeon factors.

Sephadex G-200 column chromatography was utilized to isolate three anti-neoplastic compounds (A, B and C) from sturgeon sera which were cytotoxic for human tumor cells but would not kill normal cells in vitro. Furthermore, it was found that most of the sturgeons studied produced one or more of these same compounds. Immunoadsorbent techniques were utilized to further purify and isolate the three factors in larger quantities. When these immunoadsorbent purified factors were studied by SDS-polyacrylamide gel electrophoresis, factors A and C consisted of only 2 protein bands with molecular weights slightly greater than 68,000 and factor B consisted of 8 - 10 protein bands with molecular weights ranging from 30,000 to approximately 70,000. Factor A was not destroyed by heating at 56 degrees C for 30 min and appears to kill tumor cells by binding to the target cells. Factor B also was not destroyed by heating at 56 degrees C for 30 min. However, this factor differs from factor A in that it did not kill by binding to the tumor cell. Instead, it appears that a soluble factor is responsible for the cytotoxic effects observed with factor B. Factor C is destroyed by heating at 56 degrees C for 30 min and this factor kills the tumor cells by binding to the target cells. These factors were also examined for their ability to enhance macrophage mediated cytotoxicity. Sturgeon factors A and B enhance macrophage mediated cytotoxicity whereas factor C has no effect on the ability of normal human macrophages to kill human tumor cells.

Animals↗

PubMed1983

Cytotoxicity of cancer patients' macrophages for tumor cells: purification and characterization of plasma inhibitory factors obtained from colon cancer patients.

Monocyte derived macrophages from breast and gynecologic cancer patients generally do not acquire enhanced cytotoxicity for human tumor cells after incubation with bacterial lipopolysaccharide (LPS) whereas the macrophages isolated from colon and hematologic cancer patients are cytotoxic. However, it was also found that 75% of the patients possessing cytotoxic macrophages also had a plasma factor which suppressed macrophage mediated cytotoxicity. The plasma inhibitory factor obtained from a colon cancer patient was purified utilizing Sephadex G-200 column chromatography and 4 fractions (A, B, C and D) with inhibitory activity, were isolated. When a plasma sample obtained from a colon cancer patient found to be lacking the inhibitor of macrophage cytotoxicity was fractionated, 2 fractions were isolated with inhibitory activity. These fractions corresponded to fractions A and C of the inhibitory sample. Pooled AB+ serum was also fractionated and no inhibitory fractions could be isolated. The inhibitory factors were further characterized and it was found that fractions A and B appear to be inhibitors of lysosomal enzyme activity and fraction C appears to be an inhibitor of protease activity. When the plasma from cancer patients known to possess an inhibitor of macrophage mediated cytotoxicity was examined for the presence of fraction A, B, C and D, it was found that every colon cancer patient studied possessed inhibitors A, B, C and D. Breast cancer patients possessed some combination of A, B and C but all lacked fraction D and the gynecologic cancer patients possessed some combination of factors A, B and D but they all lacked inhibitor C.

Animals↗

PubMed1983

Macrophage mediated tumor cytotoxicity--function of macrophages in human renal allograft recipients.

It has been previously reported that human peripheral blood monocyte derived macrophages acquire enhanced cytotoxicity for tumor cells after incubation in either lymphocyte mediators or lipopolysaccharide. When the macrophages obtained from renal transplant recipients were studied we observed that the macrophages obtained from 1 to 4 year post-transplant survivors were cytotoxic for tumor cells whereas, macrophages obtained from renal transplant recipients at 10 days to 7 months post-transplantation have a depressed capacity to kill human tumor cells in vitro. Furthermore, in a long term study, eight renal patients were tested repeatedly up to 1 year post-transplant. All 5 renal transplant recipients showing no clinical evidence of rejection during this 1 year study were found to possess macrophages which were non-cytolytic for tumor cells whereas 2 of the 3 patients undergoing rejection crises did possess cytotoxic macrophages. Thus, it appears that at times of rejection crises, these patients' macrophages are converted into cytolytic cells.

Adolescent↗

PubMed1983

Purified human macrophage secretions suppress tumor growth in the mouse.

Purified supernatants obtained from human macrophage supernatants or the U937 human macrophage cell line are cytotoxic for tumor cells in vitro, and when tumor bearing animals are injected with these supernatants tumor growth is suppressed in vivo. Tumor growth rate and survival times were assessed for each group of animals. At day 12 after injection of the P815 tumor cells, no difference in tumor size could be demonstrated in any of the groups. However, by day 17 the tumors in the animals treated with macrophage supernatants or the U937 macrophage cell line supernatants did not continue to increase in size as was seen in the case of the control animals. When examining survival times, it appeared that the animals treated with macrophage supernatants survived approximately 8 days longer than did the animals receiving no treatment (35-day vs 27-day survival), and the animals treated with the U937 macrophage cell line supernatants survived approximately 13 days longer than the control animals (40-day vs 27-day survival). Thus, it appears that tumor cell growth can be slowed down in vivo when purified macrophage supernatants as well as the secretions from a human macrophage cell line are injected into the tumor mass.

Animals↗

PubMed1982

Cytotoxicity of cancer patient's macrophages for tumor cells.

Monocyte derived macrophages were isolated from the peripheral blood of 66 patients with either breast, colon, gynecological or hematological cancers. The macrophages from the breast and gynecologic cancer patients generally did not acquire enhanced cytotoxicity for human tumor cells after incubation with bacterial lipopolysaccharide (LPS). However, when the macrophages isolated from colon and hematologic cancer patients were studied, more than 50% of these patients possessed cytotoxic macrophages. LPS induced macrophage mediated cytotoxicity was also found to be inhibited by factors present in many cancer patient's plasma. Twenty-three of the 50 cancer patients studied possessed a plasma inhibitor capable of suppressing macrophage mediated cytotoxicity by more than 50%. Furthermore, of these 50 patients, 47 were incapable of killing the tumor cells in vitro either because they possessed nonresponsive macrophages and/or they possessed a plasma inhibitory factor. Thus, although macrophage cytotoxic function may be normal in some patients with cancer, cytotoxicity may be inhibited in some patients by factors in autologous plasma thereby rendering the macrophages ineffective in vivo.

Adenocarcinoma↗