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Biomedical subjects

R F Barth

Publications and source records attributed to R F Barth.

At least 109 records · Page 6Linked to original sources
PubMed1977

Correlation of spontaneous leukocyte blastogenesis with human renal allograft rejection.

Spontaneous blastogenesis of peripheral blood mononuclear cells in recipients of renal allografts was studied by incorporation of 3H-thymidine. Three different levels of reactivity were observed that correlated with the patient's clinical course. Low levels of blast activity (i.e., median 680 dpm/million cells with 95% confidence interval (CI) of 480 to 880 dpm) were observed in pretransplant patients. A moderate elevation (median 3,00 dpm with CI of 2,300 to 5,300 dpm) was noted post-transplantation during quiescent intervals and following the onset of acute reversed rejection. Marked elevations, i.e., values greater than 10,000 dpm frequently were observed within 6 days prior to rejections (median 21,000 with CI of 7,400 to 34,000 dpm) and during sustained rejections (median 14,000 with CI of 8,800 to 19,600 dpm).

Graft Rejection↗
PubMed1977

Organ distribution of 99mTc- and 51Cr-labeled autologous peripheral blood lymphocytes in rabbits.

The present series of experiments was designed to compare 99mTc with 51Cr as a lymphocyte label in rabbits and to correlate organ distribution patterns as determined by postmortem counting with those observed by 99mTc gamma imaging. The distribution of 51Cr and 99mTc-labeled, viable and nonviable, unreduced or SnCl2-reduced autologous lymphocytes was determined 2 hr following intravenous injection. Viable 99mTc-labeled lymphocytes localized primarily in the liver, lungs, and kidneys or remained circulating in the blood. These compartments accounted for 34-54% of the injected radioactivity. One to three percent of the injected dose was recovered from the spleen, thyroid, bladder, and stomach, and all remaining organs accounted for less than 1%. Reduced, nonviable cells showed increased localization in the lungs and liver (48%) compared to viable unreduced cells (15%). Chromium-51-labeled lymphocytes were distributed primarily to the liver, lungs, and spleen or remained circulating in the blood. Hepatic localization differed from that observed with viable, unreduced 99mTc-labeled lymphocytes (32 vs. 12%), but vascular compartmentalization was similar (18 vs. 15%). The distribution of pertechnetate and reduced 99mTc was different from that of 99mTc-labeled cells. The urine and blood accounted for 84% of the recovered radioactivity, and for 43-45% of the injected dose, indicating that the patterns we observed with 99mTc-labeled lymphocytes truly represented cell-associated radioactivity. Similarly, the distribution of Na251CrO4 differed from that of 51Cr-labeled cells. The kidneys and urine accounted for 26% of the injected dose, compared with 5% for 51Cr-labeled lymphocytes, and only trace amounts of radioactivity were found in the lungs and spleen. The distribution of 99mTc-labeled cells, as determined by scintigraphy 90 min after injection, correlated well with data obtained by postmortem counting, suggesting that 99mTc may be applicable as a lymphocyte label for diagnostic gamma-imaging procedures.

Animals↗
PubMed1976

Studies on the interaction of the Sophora japonica lectin and concanavalin A with erythrocytes and lymphocytes.

The agglutinating activity of lectins from the seeds of Sophora japonica and Canavalia ensiformis (concanavalin A) with human and murine erythrocytes and lymphocytes have been compared to one another and related to the mitogenic and immunosuppressive properties of these purified proteins. The S. japonica lectin, which demonstrates blood group specificity, is more active than concanavalin A with human erythrocytes, but has a much lower reactivity than concanavalin A with murine red blood cells. Ficin treatment of human erythrocytes results in an increase in agglutinability by both lectins as well as causing the appearance of S. japonica lectin receptors on type O cells. Treatment of murine reythrocytes with ficin alone or followed by beta-galactosidase causes the cells to be more reactive with concanavalin A. Beta-Galactosidase alone has no observable affect on the cells. In contrast, the agglutinability of cells by the S. japonica lectin increases after ficin treatment but is not affected by beta-galaetosidose treatment either after or in the absence of ficinization. Murine lymphocytes react with both lectins in a manner paralleling the agglutination patterns of murine erythrocytes. The S. japonica lectin appears to be devoid of mitogenic and immuno-suppressive activity, in contrast to concanavalin A which suppresses the T helper-dependent antibody response to sheep erythrocytes. These results are discussed in terms of the types of lectin receptors on lymphocytes related to agglutination, induction of blastogenesis and immuno-suppression.

Animals↗
PubMed1975

Agglutination of 2,4-dinitrophenyl-tagged normal human leukocytes by concanavalin A: possible relationship to their ability to evoke production of leukemia-associated antibodies.

Normal peripheral blood leukocytes were tagged with 2, 4-dinitrofluorobenzene at a ratio of 10-11 molecules/cell. One-tenth ml of various concentrations of concanavalin A (Con A) was added to 0.2 ml of either tagged or untagged cells (5 times 10-6/ml) and incubated for 20 minutes at ambient temperature, after which agglutination was scored visually. A readily discernible quantitative difference in the agglutinability of 2, 4-dinitrophenyl (DNP)-tagged versus untagged cells was seen at all concentrations of Con A in the range of 12.5 800 mug/ml. The reaction was maximal at 24 degrees C, somewhat diminished at 37 degrees C, and minimal at 4 degrees C. The agglutination of DNP-tagged leukocytes by 50 mug Con A/ml was completely blocked with 0.1 M methyl-alpha-D-glucopyranoside (alpha-MG), but as low a concentration as 0.001 M alpha-MG inhibited agglutination of untagged cells. The ability of Con A to agglutinate DNP-tagged normal leukocutes may be attributed to a lowering of the zeta potential, a topographic rearrangement of receptor sites, or the formation of new antigenic determinants similar to those found on malignant cells. The last alternative would be consistent with the observation that DNP-tagged normal leukocytes could evoke the production of antibodies that reacted with leukemic granulocytes.

Agglutination↗
PubMed1975

Suppressor T cells and host resistance to tye 111 pneumococcus after treatment with antilymphocyte serum.

The antibody response to type III pneumococcal polysaccharide (SS-II) was significantly increased in mice treated with antilymphocyte serum (ALS). BALG/c mice given 0.25 ml of ALS on days -1, 0, and 1 relative to the days of immunization with 0.5 mug of SSS-II had a 20-fold increment (11,383 increased to 199,917) in the number of splenic plaque-forming cells enumerated on day 5 compared with untreated, immunized controls. This effect has been attributed to the elimination of subpopulation of thymus-derived lymphocytes (T cells) that has suppressor function. The present series of experiments relate the augmented antibody response to SSS-II in mice treated with ALS to increased host resistance after infection with Streptococcus pneumoniae, type III (Pn-II). The 50% lethal dose of Pn-III in niminnunized mice was 102 and the 100% lethal dose was 103 organisms. Mice immunized with 0.5 mug of SSS-III and challenged 5 days later with Pn-III were completely protected against a dose of up to 108 organisms. Mice treated with 0.25 ml of ALS on days -1, 0, and 1, immunized with SSS-III on day 0, and challenged with 2.5 X 10(9) Pn-III on day 5 had a mean survival time of greater than 100 h compared with 16 h for immunized non-serum-treated controls. Animals given a single injection of ALS before immunization showed no increase in resistance, whereas mice treated after immunization had significant prolongation of survival times. Untreated, immunized mice challenged with 5 X 10(9), 1 X 5 X 10(8) Pn-II survived 14 to 19 h, whereas ALS-treated animals had mean survival times of 48, 174, and 222 h, respectively. These findings suggest that immunoregulatory T cells may have a biologically significant effect in a narrow zone in which the normal host immune response is insufficient but still potentially capable of providing some additional degree of protection if suppressor cells are elimated.

Animals↗
PubMed1975

Agglutination of leukemic and 2,4-dinitrophenyl-tagged normal human lymphocytes by wheat germ agglutinin.

The present study was undertaken to determine if leukemic and 2,4-dinitrophenyl (DNP)-tagged normal human lymphocytes shared common receptors for Wheat Germ Agglutinin (WGA), a lectin capable of reacting with malignant cells. Normal peripheral blood lymphocytes were tagged with 2,4-dinitrofluorobenzene (DNFB) at a ratio of 10-11 molecules/cell. Various concentrations of WGA were added to leukemic or tagged or untagged normal lymphocytes and incubated for 20 minutes at 37 degrees C, after which agglutination was scored visually. A readily discernible quantitative difference in the agglutinability of leukemic and DNP-tagged versus untagged normal cells was seen at all concentrations of WGA in the range of 50-800 mug/ml. The reaction was maximal when a ratio of 10-11 molecules of DNFB/cell was used for tagging and decreased progressively with 10-8, 10-6, 10-4, 0r 10-2 molecules. The agglutination of leukemic and DNP-tagged normal lymphocytes by 200 mug/ml of WGA was completely blocked by 0.1 M N-acetylglucosamine (GlcNAc) while as low a concentration as 0.001 M GlcNAc inhibited the reactivity of untagged cells. Since the agglutination of leukemic and DNP-tagged normal lymphocytes was equally inhibited by GlcNAc, this suggests that the same or similar receptor sites were involved in the two reactions. On the basis of our observations we propose that the initial step in the agglutination of leukemic and DNP-tagged normal lymphocytes by WGA IS THE BINDING OF THE LECTIN TO SPECIFIC RECEPTORS RATHER Than to DNP residues on the cell surface, since leukemic cells tagged with DNFB did not show increased agglutinability.

Acetylglucosamine↗
PubMed1975

Receptor sites for antigen-antibody complexes on cells derived from solid tumors: detection by means of antibody sensitized sheep erythrocytes labeled with technetium-99m.

Surface receptor sites for the Fc portion of antigen-antibody complexes were demonstrated on cells derived from three methylcholanthrene-induced fibrosarcomas, one of strain C3H and two of strain BALB/c origin, two spontaneously occurring malignant melanomas (B16 in strain C57BL/6 and Harding-Passey in strain BALB/c mice), a Moloney sarcoma virus-induced tumor of strain BALB/c origin and the Walker 256 carcinosarcoma of Holtzman rats. Primary cell cultures derived from these tumors adsorbed technetium-99m labeled, antibody-sensitized sheep erythrocytes (99mTc EA) as determined either by visual scoring of adherence or radioisotopic quantitation. Depending upon the tumor tested, from 20% to greater than 95% of the target cells absorbed 99mTc EA. All cells lost their reactivity after 1 or 2 passages in vitro, but this was regained after a single passage in vivo. Indicator erythrocytes coated with F(ab')2 fragments of the sensitizing sheep erythrocytes (SRBC) antiserum did not adhere thereby demonstrating that the hemadsorption required an intact Fc portion of the antibody molecule. Adherence of 99mTc EA was blocked by soluble immune complexes prepared with ovalbumin and rabbit antibody directed against it and Escherichia coli 055:B5 lipopolysaccharide and mouse antibody directed against it. Normal rabbit or mouse serum, immune serum, or antigen alone did not block adherence of 99mTc EA thereby demonstrating that the receptors had greater affinity for immune complexes than for either antigen or antibody alone. The existence of membrane receptors on tumor-derived cells which react with the Fc portion of antigen-antibody complexes may provide an explanation for the mechanism by which immune complexes are capable of blocking cell-mediated tumor cell destruction irrespective of whether the receptors are on the tumor cells themselves or on admixed lymphocytes and macrophages.

Animals↗
PubMed1975

Organ distribution of 99m-Tc-and 51-Cr-labelled thymocytes.

We have employed 99mTc as a radioisotopic label to study the organ distribution of murine thymocytes. The compartmentalization of 99mTc-labeled cells that had not been reduced by treatment with stannous chloride was similar to that of 51Cr-labeled cells and was characterized initially by 48-50% uptake of the injected radioactivity by the lungs. Increased hepatic and splenic and decreased pulmonary localization were noted at 1 hr and these shifts were more pronounced by 4 hr. Technetium-99m-labeled cells reduced by stannous chloride had significantly different patterns of hepatic, pulmonary, and splenic localization and at 4 hr the lungs still retained 24% of the injected radioactivity compared with only 3% in the spleen. Size distribution studies revealed that unlabeled as well as unreduced and reduced 99mTc-labeled thymocytes were almost identical to one another so that differences in compartmentalization could not be attributed to this factor. Since reduction with stannous chloride did not alter the distribution of 51Cr-labeled cells, this suggested some type of complex interaction between stannous ions and the labeling species of 99mTc. The in vivo localization of intravenously administered Na99mTcO4 and Na2CrO4 was markedly different from the corresponding radiolabeled cells thereby indicating that the distribution patterns that we observed truly represented cell-associated radioactivity. Although it may not necessarily be the proper reference point, the similarity in organ distribution of 99mTc- and 51Cr-labeled cells should allow direct comparison of previously reported data employing this radionuclide and that obtained in future studies with 99mTc.

Animals↗
PubMed1975

Detection of cell-bound immunoglobulins by a radioisotopic micro-mixed hemadsorption reaction with technetium-99m-labeled erythrocytes.

The mixed hemadsorption (MHA) reaction detects antibodies reactive with cell surface antigens by means of antiglobulin-coated indicator erythrocytes. We have developed a radioisotopic modification which employs sheep erythrocytes (SRBC) that have been prelabeled with technetium-99m (99mTc), a high specific acitivity metastable gamma-emitter of short half life. The 99mTc MHA reaction was performed on human and murine cells cultured in Micro-test II plated with six replicate wells per serum dilution. Antibody activity in species-specific xenoantisera and mono- and polyspecific alloantisera was detected in high titer. The sensitivity of 99mTc micro-mixed hemadsorption was 2 times that of the visual assessment of mixed hemadsorption, 100 to 200 times that of the 125-I-mixed antiglobulin reaction and 500 to 1000 times more sensitive than indirect immunofluorescence. The assay system was applied successfully to confirm the species of origin of a panel of previously karyotyped human and mouse cell lines. Our results indicate that the 99mTc micro-mixed hemadsorption method is a rapid, sensitive, quantitative test for the detection of cell surface antigens and membrane reactive antibodies.

Animals↗