A tumor-derived protein which provides T-cell costimulation through accessory cell activation

A recently described tumor-derived glycoprotein, designated 90K, has been shown to have positive effects on the generation of cytotoxic effector cells (NK/LAK) from human PBMC. To determine the mechanism of these effects, we have examined the effects of 90K on cytokine production by human PBMC. A culture of normal PBMC with 90K alone did not result in IL-2 secretion; however, in coculture with suboptimal doses of ConA, 90K increased IL-2 secretion by PBMC. Coculture of PBMC with 90K and ConA also resulted in increased production of the cytokines IL-1, IL-6, GM-CSF, and TNF alpha. T cells depleted of accessory cells failed to respond to ConA alone, 90K alone, or the combination of ConA and 90K, suggesting that this protein does not have a direct effect on T cells. However, 90K alone was sufficient to induce cytokine production by unfractionated PBMC (IL-1, IL-6, GM-CSF, and TNF alpha) or by CD14-enriched PBMC (IL-1 and IL-6). In addition, expression of ICAM-1 was increased on a human monocytic cell line cultured with purified 90K in the absence of any other stimulus. This 90K-induced upregulation of ICAM-1 expression was accompanied by an increased accessory function of the monocytes, demonstrated by their ability to support ConA-induced activation of peripheral blood T cells. Based on the current data, we propose a model in which 90K activates accessory cells, resulting in the secretion of cytokines and the expression of adhesion molecules, which in turn act as costimulatory signals for T-cell activation. Activated T cells then produce cytokines such as IL-2, which lead to a more vigorous cell-mediated immune response to tumor cells and virus-infected cells. Thus, 90K shows promise as an immunotherapeutic reagent for diseases such as cancer and viral infection.

Cytokine-mediated expansion of 5-FU-resistant peripheral blood stem cells

We evaluated the expansion capacity of untreated and 5-fluorouracil (5-FU)-resistant peripheral blood stem cells (PBSC) after 7-day incubation with interleukin-1 (IL-1) plus IL-3 plus stem cell factor (SCF) or with medium alone. We found a significant increase in the proportion of CD34+ cells in the PBSC fraction resistant to 25 micrograms/mL 5-FU after 7-day incubation with IL-1 plus IL-3 plus SCF as compared with the untreated fraction (p = 0.011). We also showed that 5-FU-resistant PBSC have a greater capacity for expansion of IL-1/IL-3/SCF-responsive immature progenitors (p = 0.05), amplification of IL-3 plus GM-CSF responsive progenitors (p = 0.01), and production of committed single growth factor-responsive (granulocyte-macrophage colony-stimulating factor [GM-CSF]) precursors (p = 0.01) than the untreated PBSC. The expansion of all types of progenitors and CD34+ cells was only observed after 7-day incubation with IL-1 plus IL-3 plus SCF. These results suggest that PBSC contain a primitive stem cell population with an enhanced expansion capacity that is identified by 5-FU resistance. As these cells can be expanded in vitro, they may then be suitable for a number of clinical applications.

Development of an efficient serum-free semisolid culture system for the evaluation of hematopoietic progenitors

Three different combinations of serum-free (SF) media proposed by Drouet et al., Ieki et al., and Wu et al. were tested to assess their ability to replace fetal calf serum (FCS) in a human hematopoietic progenitor semisolid culture system using human bone marrow and peripheral blood stem cells. This study confirmed that two (Drouet and Wu) of the three SF media tested were able to induce progenitor growth in the presence of either 5637-conditioned medium or a defined combination of growth factors: stem cell factor (SCF), interleukin-1 (IL-1), interleukin-3 (IL-3), and erythropoietin (EPO). The best results were obtained using the SF media described by Wu. The number of 5637-stimulated CFU-GM obtained with the Wu SF media was not different from that obtained with FCS-supplemented media when cultures were assessed on day 14 (79 +/- 14 versus 104 +/- 17), day 18 (64 +/- 11 versus 79 +/- 12), or day 21 (58 +/- 13 versus 62 +/- 12). Similar findings were obtained when the previously defined combination of growth factors was used to stimulate progenitor growth. Because the Wu medium was the most efficient SF medium to promote hematopoietic progenitor growth, we attempted to improve its efficacy by modifying the concentrations of the various components. A reduction in the concentration of bovine serum albumin (BSA) dramatically reduced the total number of clonogenic elements. Soybean lectin was not essential for colony proliferation; however, its presence had an favorable effect on the overall appearance of the colonies (greater number of cells per colony).(ABSTRACT TRUNCATED AT 250 WORDS)

Quality and functional capacity of the bone marrow microenvironment of autologous blood stem cell transplantation (ABSCT) recipients

We have previously reported that the rate of haematopoietic recovery following Autologous Blood Stem Cell Transplantation (ABSCT) could be influenced by the type of conditioning regimen or by the underlying disease. Furthermore, Peripheral Blood Stem Cell (PBSC) growth was found to be sensitive to stimulation by irradiated allogeneic stromal layers. In the present study, we used the long term culture system (LTC) to investigate the quality of the bone marrow (BM) microenvironment from patients who had undergone ABSCT for either Malignant Lymphoma (ML, 13 patients) or Multiple Myeloma (MM, 8 patients) after conditioning regimens comporting myeloablative chemotherapy (CT) or Total Body Irradiation (TBI). Among the 13 ML patients, 10 received CT conditioning and 9 of the 10 BM samples developed a complete confluent stromal layer. The remaining 3 ML patients received TBI prior to ABSCT and 2 of the 3 samples developed confluent stroma. In contrast, when LTC were established with BM from the 8 MM patients, all of whom were treated with TBI prior to ABSCT, only 3 of the 8 marrow samples developed a complete confluent stromal layer. Thus BM from patients who had received CT conditioning therapy tended to form confluent stroma more often than BM from those who had received TBI (p = 0.08). CFU-GM production was also evaluated for the stromal layers derived from all transplanted patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Low levels of amniotic fluid pregnancy specific beta-1-glycoprotein in Down's syndrome

Amniotic fluid levels of beta-1-glycoprotein (SP1) were measured in 46 cases of Down's syndrome and compared with levels in 106 pregnancies of normal karyotype from 10 to 23 weeks of gestation. In normal pregnancies, levels rose from 87.5 iu/l at 10 weeks to a peak of 610.0 iu/l at 19 weeks of gestation. In cases of Down's syndrome, levels were reduced prior to 19 weeks of gestation (median multiple of the median, MoM = 0.75, P = 0.02). This effect was most marked prior to 16 weeks of gestation when the median multiple of the median (MoM) was 0.51 (P = 0.006). These data demonstrate that amniotic fluid levels of SP1 are low in Down's syndrome before 19 weeks of gestation.

Cytokine-mediated expansion of 5-FU resistant peripheral blood stem cells and bone marrow: self-renewal and commitment capacity

To further characterize the primitive stem cell subpopulation present in chemotherapy mobilized peripheral blood stem cells (PBSC), we evaluated the functional characteristics of 5-FU-resistant PBSC and normal bone marrow (BM) cells after 7 days incubation with IL-1 + IL-3+SCF. The resulting 5-FU-resistant cells were evaluated for (1) the production of GM-CSF-responsive clonogenic elements (CE), (2) the production of IL-3+GM-CSF-responsive CE, and (3) their self-renewal capacity (production of IL-1+IL-3+SCF-responsive CE). We also evaluated the percentage of CD34+ cells, the percentage of cells in S phase of the cell cycle, and the number of nucleated cells before and after cytokine-mediated expansion. We demonstrated an overall loss in nucleated cells after cytokine-mediated expansion in all cell fractions. We demonstrated a significantly greater increase in the percentage of CD34+ cells in the 5-FU-resistant PBSC fraction as compared to 5-FU-resistant BM cells (p = 0.012). We also showed that 5-FU-resistant PBSC have a greater capacity for self-renewal, amplification of IL-3+GM-CSF-responsive progenitors, and the production of committed GM-CSF-responsive progenitors as compared with BM cells, but this did not reach statistical significant. These results suggest that PBSC contain a truly primitive stem cell with an enhanced self-renewal and differentiative capacity that is recruited by 5-FU resistance and IL-1+IL-3+CSF-mediated expansion.(ABSTRACT TRUNCATED AT 250 WORDS)

Activated T cells in an animal model of allergic conjunctivitis

The aim of this study has been to determine whether the presence of lymphocytic infiltrates observed in the histology of ocular allergic conditions in humans or in the late phase of ocular anaphylactic reactions in experimental animals is a non-specific event dependent only on the degranulation of mast cells, or is conditioned by a specific response to antigen. With this in mind, responses to antigen and to a non-immunological mast cell degranulator (compound 48/80) were compared in an experimental model of allergic conjunctivitis. Rats were sensitised to ovalbumin and challenged topically in the left conjunctival sac either with ovalbumin or compound 48/80. The presence of T cells and activated T cells in the infiltrate was studied by immunohistochemical staining on conjunctival tissue obtained at 4, 24, and 48 hours after challenge. Ovalbumin sensitised and challenged rats showed increased numbers of T cells in the conjunctival infiltrate, statistically significant when compared with compound 48/80 challenged rats at 48 hours and with controls at 4, 24, and 48 hours. The number of T cells was significantly higher in compound 48/80 challenged rats only at 48 hours when compared with controls. As for the number of activated T cells, only ovalbumin sensitised and challenged rats showed significantly increased levels of these cells compared with both sensitised animals challenged with compound 48/80 and controls at 4 and 24 hours after challenge. These results suggest that the infiltration of the conjunctiva by activated T lymphocytes is, at least in part, dependent on a specific response to antigen.

Interferon gamma is effective for BM purging in a patient with CML

We report a case of Ph-positive CML where the BM was incubated for 24 h with 10(3) IU/ml IFN gamma and then cultured in liquid media for 4 weeks. After 24 h incubation, there was no differential sensitivity of CML CFU-GM to IFN gamma compared with untreated BM. Subsequent long-term culture (LTC) of the IFN gamma treated CML BM, however, demonstrated a 75% inhibition of production of CFU-GM from the second week onwards. Using PCR, we were able to demonstrate two types of BCR-ABL transcript in the diagnostic BM. After 4 weeks of LTC, the J(bcr b3/ABL II) RNA transcript persisted in the untreated BM, whereas neither BCR/ABL RNA transcripts were detected in the culture established with IFN gamma-treated CML BM. This study has two points of interest with the demonstration of (1) a possible antileukaemic effect of IFN gamma on the progenitors generated in the LTC system, and (2) the use of highly sensitive PCR technology to evaluate the effectiveness of IFN gamma to purge CML BM of Ph-positive cells.

5-fluorouracil permits access to a primitive subpopulation of peripheral blood stem cells

Peripheral blood stem cells (PBSC) contain a mixture of mature and immature hematopoietic progenitors. Resistance to 5-Fluorouracil (5-FU) has been used to identify and characterize primitive quiescent stem cells among bone marrow (BM) cells. To see if the same technique could be used to isolate a similar population of cells among PBSC, low-density peripheral blood mononuclear cells (PBMNC) were collected by cytapheresis in the regenerative phase after high-dose chemotherapy from patients with hematological malignancies. These PBMNC were incubated with increasing concentrations of 5-FU for 24 h. The viable 5-FU resistant cells were then cultured in semi-solid media in the presence of either single cytokines: TCM 5637, Granulocyte Macrophage Colony Stimulating Factor (GM-CSF), or a combination of cytokines: interleukin 1 (IL-1) IL-1 + IL-3 + 5637, IL-1 + IL-3 + Stem Cell Factor (SCF). Low concentrations (5-10 micrograms/ml 5-FU) eliminated mature day 7 Colony Forming Units-Granulocyte Macrophage (CFU-GM) and spared day 7 clusters while enriching for day 14 CFU-GM, irrespective of the growth factors used. Higher concentrations of 5-FU (15, 20, 25 micrograms/ml) selected for later forming clonogenic elements. A combination of synergistic growth factors was required for the development of morphologically identifiable clonogenic elements resistant to 25 micrograms/ml 5-FU at day 21 of culture. Further experimentation demonstrated that SCF could effectively replace TCM 5637 in the cytokine combination for the detection of primitive late forming clonogenic elements. The presence of SCF potentiated colony formation by 5-FU resistant PBMNC. It was confirmed that GM-CSF alone was unable to support colony formation by PBMNC resistant to 25 micrograms/ml. These observations demonstrate that PBSC contain a heterogenous mixture of hematopoietic progenitors and that incubation with 25 micrograms/ml 5-FU permits access to a quiescent primitive stem cell population that requires a combination of synergistic growth factors for the development of morphologically identifiable clonogenic elements at day 21. Taken together, these results suggest that PBSC have similar characteristics to BM derived stem cells.

Low serum retinol is associated with increased severity of measles in New York City children

Children with no known prior vitamin A deficiency exhibited a significant decline in their serum retinol levels during the acute phase of measles. This decline in circulating retinol was associated with increased duration of fever, higher hospitalization rates, and decreased antibody titers.

Mobilized blood stem cells: immunophenotyping and functional characteristics

High levels of peripheral blood stem cells (PBSC) can be collected from patients with hematopoietic malignancies or solid tumors after high-dose chemotherapy and/or growth factors. Rapid, complete, and durable hematopoietic reconstitution has been observed in patients who have been transplanted with PBSC after conditioning with supralethal myeloablative therapy. We will review the recent data concerning the immunophenotype and functional capacities of mobilized blood stem cells. PBSC seem to be comprised of a mixture of primitive and committed hematopoietic progenitors and are not that different from bone marrow-derived stem cells.

Incomplete stroma formation after allogeneic marrow or autologous blood stem cell transplantation

Long term and semi-solid culture techniques were used to evaluate the quality of stroma produced by bone marrow from 33 normal subjects and 57 patients (46 allogeneic bone marrow and 11 autologous blood stem cell transplant recipients). Bone marrow from transplant recipients was capable of sustained CFU-GM and nucleated cell production in long term culture. However, only 13% of the marrow investigated developed a complete, confluent stromal layer. These stromal abnormalities were observed in spite of complete hematopoietic reconstitution after transplantation and rarely improved with time. Our results suggest that the hematopoietic microenvironment is very fragile and susceptible to long term damage as a result of chemotherapy and the conditioning regimes used prior to transplantation.

Air oxidation of hydrazine. 1. Reaction kinetics on natural kaolinites, halloysites, and model substituent layers with varying iron and titanium oxide and O- center contents

Air oxidation of hydrazine was studied by using a group of kaolinites, halloysites, and substituent oxides as models for the tetrahedral and octahedral sheets. The rate was found to be linear with oxygen. The stoichiometry showed that oxygen was the primary oxidant and that dinitrogen was the only important nitrogen-containing product. The rates on kaolinites were strongly inhibited by water. Those on three-dimensional silica and gibbsite appeared not to be. That on a supposedly layered silica formed from a natural kaolinite by acid leaching showed transitional behavior--slowed relative to that expected from a second-order reaction relative to that on the gibbsite and silica but faster than those on the kaolinites. The most striking result of the reaction was the marked increase in the rate of reaction of a constant amount of hydrazine as the amount of clay was increased. The increase was apparent (in spite of the water inhibition at high conversions) over a 2 order of magnitude variation of the clay weight. The weight dependence was taken to indicate that the role of the clay is very important, that the number of reactive centers is very small, or that they may be deactivated over the course of the reaction. In contrast to the strong dependence on overall amount of clay, the variation of amounts of putative oxidizing centers, such as structural Fe(III), admixed TiO2 or Fe2O3, or O- centers, did not result in alteration of the rate commensurate with the degree of variation of the entity in question. Surface iron does play some role, however, as samples that were pretreated with a reducing agent were less active as catalysts than the parent material. These results were taken to indicate either that the various centers interact to such a degree that they cannot be considered independently or that the reaction might proceed by way of surface complexation, rather than single electron transfers.

Long-term culture of peripheral blood stem cells: the effect of the addition of an irradiated stromal layer

We have studied peripheral blood stem cells (PBSC) collected by cytapheresis following intensive chemotherapy, from 13 patients with acute leukemia, in long term culture (LTC). Peripheral blood was cultured with (n = 10) and without (n = 21) the addition of a preformed, irradiated stromal layer. In this latter LTC our results confirm that peripheral blood is capable of producing CFU-GM and nucleated cells in the absence of the formation of an adherent stromal layer. However, peripheral blood cultured in the presence of an irradiated stromal layer is capable of a significantly higher proliferative response (total production of CFU GM per flask - mean = 57529) than in the absence of an irradiated stromal layer (total production of CFU GM per flask - mean = 26739, p less than 0.03). Our results suggest that PBSC contain a primitive nonplastic adherent cell that requires the presence of a stromal layer for its expression. These findings provide further support for the use of peripheral blood stem cells for autologous transplantation.

Creating an effective marketing team. Six leading healthcare marketers offer their perspectives. Interview by Richard D. Stier

Richard D. Stier, senior vice president and chief marketing officer, Adventist Health System, Shawnee Mission, Kansas, asked six top healthcare marketers to assume they had just been appointed vice president and chief marketing officer for a medium-sized, 300-bed, not-for-profit community hospital. Their mission: Create the most effective, powerhouse marketing team in the country.

Mid-trimester levels of alphafetoprotein in the screening of low birthweight

Elevated maternal levels of alphafetoprotein (AFP) in midtrimester are believed by some to be a useful screening test for premature labour, low birthweight and low birthweight for gestation. In a prospective study on 887 randomly selected pregnant women we found that although there was an association between low birthweight and elevated AFP, the test would miss five out of every six cases of low birthweight and there would be nine false-positives for every case correctly identified. The test is not therefore sufficiently predictive of low birthweight to be of value as a screening test for this condition.

Dramatic increase of placental protein 5 levels following injection of small doses of heparin

In the course of an investigation on the effects of thyroid releasing hormone in pregnant women we noted a dramatic increase in the levels of placental protein 5 (PP5) in maternal blood. This increase ranged from 10 times to over 40 times the basal levels. Further study showed that the rise was associated with the use of heparin to maintain the patency of the cannula through which the samples were collected. Furthermore, the phenomenon appeared to be systemic rather than local, and may well be due to a direct effect of heparin on PP5 secretion by the placenta.

Differential effects of inhibitors of purine metabolism on two trichomonad species

Tritrichomonas foetus and Trichomonas vaginalis are both incapable of de novo purine nucleotide synthesis. Previous studies indicated that T. foetus relies mainly on the salvage of hypoxanthine and subsequent conversion of IMP to AMP and GMP, whereas T. vaginalis depends on direct conversions of exogenous adenosine to AMP and guanosine to GMP without much interconversion between the two nucleotides. These two different types of purine salvage suggest the possibility of differential sensitivities between the two species of trichomonad flagellates toward different purine antimetabolites. Mycophenolic acid, hadacidin, 8-azaguanine, and formycin B inhibited the growth of T. foetus but had no effect on T. vaginalis. Mycophenolic acid acted by blocking conversion of IMP to GMP, hadacidin inhibited conversion of IMP to AMP, and 8-azaguanine was incorporated into the T. foetus nucleotide pool, likely via hypoxanthine phosphoribosyl transferase. Formycin B was converted to 5'-monophosphate in T. foetus and inhibited the conversion of IMP to AMP. Its precise mechanism of action on T. foetus remains, however, to be elucidated. Alanosine, whose ribonucleotide derivative is a potent inhibitor of adenylosuccinate synthetase, had no effect on the growth or hypoxanthine incorporation in T. foetus, which may be due to the lack of conversion of alanosine to the ribonucleotide because of the absence of de novo purine nucleotide synthesis in parasites. Four adenosine analogs, adenine arabinoside, tubercidin, sangivamycin, and toyocamycin, were found inhibitory to the growth of T. vaginalis but showed little effect on T. foetus growth. Further investigations suggested that these four compounds acted on T. vaginalis by blocking incorporation of adenosine into the adenine nucleotide pool.

Tritrichomonas foetus: partly defined cultivation medium for study of the purine and pyrimidine metabolism

A partly defined medium was successfully designed for the cultivation of Tritrichomonas foetus, an anaerobic protozoan parasite of cattle. The medium consists of hypoxanthine, uracil, and thymidine as the sole precursors of nucleotides in T. foetus. Elimination of any one of the three precursors from the medium led to cessation of T. foetus growth. The information provided by this medium verifies our previous observations that T. foetus is incapable of de novo purine and pyrimidine synthesis, that hypoxanthine can be converted to AMP and GMP, that uracil is incorporated into all pyrimidine ribonucleotides including UDP-glucose--the precursor of glycogen synthesis, and that thymidine is the only precursor of TMP. The omission of folate from the medium, without affecting growth of T. foetus, also supports our previous finding that the parasite does not have functioning dihydrofolate reductase or thymidylate synthetase. The successful plating of T. foetus on agar plates incorporating the partly defined medium with near 100% plating efficiency makes it possible to isolate T. foetus mutants for further studies of purine and pyrimidine metabolism in this parasite.

Purine salvage by Tritrichomonas foetus

The anaerobic protozoon Tritrichomonas foetus was found incapable of de novo purine synthesis by its failure to incorporate radiolabeled glycine or formate into the nucleotide pool. It had, on the other hand, high activities in incorporating adenine, hypoxanthine or inosine. Radiolabel pulse-chase experiments indicated that adenine, hypoxanthine and inosine all entered the pool through conversion to IMP. The parasite contained hypoxanthine phosphoribosyl transferase, adenine deaminase and inosine phosphorylase, but no adenine phosphoribosyl transferase, inosine kinase or inosine phosphotransferase activity. Adenine and inosine had to be converted to hypoxanthine before incorporation. Adenosine was also rapidly converted to hypoxanthine in T. foetus cell-free extracts, but the presence of adenosine kinase in the parasite allowed some conversion of adenosine directly to AMP. Guanine and xanthine were directly incorporated into GMP and XMP, probably due to the guanine and xanthine phosphoribosyl transferase. There were also strong enzyme activities which convert guanosine to guanine and guanine to xanthine. A guanosine phosphotransferase was found in the 10(5) X g sedimentable fraction of T. foetus, and was capable of converting some guanosine to GMP. This network of T. foetus purine salvage suggests the importance of hypoxanthine-guanine-xanthine phosphoribosyl transferase activities in the parasite.

A method for the purification of placental protein 5 (PP5) from placental extracts

We describe a method for the preparation of purified PP5 suitable for use as a tracer ligand in RIA. The method is based on the observation that PP5 will bind to heparin and employs a heparin-Sepharose column as a key step in the procedure.

Rewarding and aversive effects of morphine: temporal and pharmacological properties

To assess morphine-induced location preferences and flavor aversions, rats were administered morphine sulfate (10 mg/kg, IP) either immediately before (Experiment 1) or immediately after (Experiment 2) confinement for 20 min in one side of a shuttlebox with access to a flavored solution. On control trails the rats were administered saline and confined for 20 min on the opposite side with a differently flavored solution. In subsequent choice tests, it was found that morphine injections before confinement produced a preference for the side associated with morphine and indifference to the flavors, whereas morphine injections after confinement produced an aversion to the flavor paired with morphine and indifference to the sides. Experiments 3 and 4, using a procedure similar to that of Experiment 1, showed that naloxone (1 mg/kg, IP) blocked the morphine-induced side preference, although given alone it was without effect in this test.

Determination of the identity and organization of messenger RNAs within DNA

We outline methods for identifying DNAs containing sequences complementary to specific mRNAs, and provide a number of complementary approaches for mapping the arrangement of mRNAs along the DNA. These methods, together with S1 nuclease mapping and the direct visualization of R-loops with the electron microscope, provide a comprehensive approach to defining the architecture of mRNAs coding for specific polypeptides and the arrangement of RNA transcripts along the genome. This detailed cartographic information can then be used to study the steps in the processing of mature mRNAs and determine the modes by which the expression of specific genes is regulated.