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Biomedical subjects

J E Groopman

Publications and source records attributed to J E Groopman.

At least 73 records · Page 4Linked to original sources
PubMed1992

Effects of transforming growth factor beta on megakaryocytic cell fusion and endomitosis.

Transforming growth factor beta (TGF-beta) is a cytokine secreted by megakaryocytes and platelets which inhibits the proliferation of megakaryocyte progenitors in vitro. We have studied the effects of TGF-beta on more mature megakaryocytes, using cell lines CMK, DAMI, and CHRF as well as isolated human marrow megakaryocytes as models. Proliferation of these megakaryocytic cell lines was inhibited by TGF-beta 1 at concentrations of 10-100 ng/ml. Although these cell lines secreted small amounts of TGF-beta (up to 100 pg/ml), it was predominantly in an inactive form. Upon induction with 12-phorbol 13-myristate acetate (PMA), they secreted greater amounts of TGF-beta (500-1250 pg/ml), most of which was still inactive in a bioassay. Addition of exogenous active TGF-beta 1 had no effect on ploidy of unstimulated megakaryocytic cell lines or on [3H]thymidine incorporation of isolated human marrow megakaryocytes. Following PMA induction, exogenous TGF-beta 1 had a significant inhibitory effect on ploidy in DAMI cells but not CMK or CHRF cells, suggesting that the phenomenon is restricted to DAMI cells. Because certain cell lines may fuse in vitro, and phorbol esters can promote this phenomenon, we investigated the possibility that fusion was contributing to the increase in ploidy in megakaryocytic cells. Unstimulated megakaryocytic cells did not show spontaneous fusion; when PMA was added to the cultures, fusion was markedly increased, particularly in DAMI cells. These results demonstrate that in vitro fusion accounts for a proportion of the apparent increase in DNA content of megakaryocytic cell lines upon induction with PMA.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed1992

Quantitation of plasma human immunodeficiency virus type 1 RNA by competitive polymerase chain reaction.

Clinical measures of human immunodeficiency virus (HIV) type 1 activity in vivo are limited and hinder the assessment of antiretroviral therapies. Reported here is a method for quantitating HIV-1 RNA in human plasma using the polymerase chain reaction (PCR). This method uses an internal cRNA standard generated from a cloned 113-bp deletion mutation of a highly conserved HIV-1 gag region sequence. The mutant cRNA (K4) was shown to amplify with efficiency equivalent to that of wild-type HIV-1. Known quantities of K4 cRNA added to wild-type HIV-1 in a competitive PCR strategy using a radiolabeled primer permitted quantitation of wild-type HIV-1 RNA over four orders of magnitude (10(3)-10(6) RNA copies). RNA isolated from plasma from AIDS patients yielded 10(3) to 8 x 10(4) HIV-1 RNA copies/ml of plasma with an average intrasample coefficient of variation of .26. This method offers a sensitive assay with a broad dynamic range for monitoring HIV-1 activity in the plasma of AIDS patients. It may provide a useful tool for assessing the effects of antiretroviral therapy.

Binding, Competitive↗
PubMed1992

Hematopoietic growth factors in AIDS.

Three hematopoietic growth factors, erythropoietin, GM-CSF, and G-CSF, have all been evaluated in the context of HIV infection. Recombinant human Epo is currently licensed for therapy of anemia related to zidovudine and is well tolerated in this patient population. Although myelosuppression can clearly be overcome using recombinant human GM-CSF or G-CSF in HIV-infected hosts, the clinical benefits for such patients are still not determined. It is likely that these growth factor therapies will allow for delivery of certain important myelosuppressive medications that otherwise could not be tolerated. Improvements in virological quantitation in vivo should help settle the controversies regarding modulation of HIV replication caused by cytokine treatment. The clinical use of hematopoietic growth factors in HIV disease requires further study with regard to the optimization of increases in blood cell number and/or modulation of blood cell function.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Recombinant human granulocyte-macrophage colony-stimulating factor ameliorates zidovudine-induced neutropenia in patients with acquired immunodeficiency syndrome (AIDS)/AIDS-related complex.

To evaluate the effect of recombinant granulocyte-macrophage colony-stimulating factor (GM-CSF) on patients with acquired immunodeficiency syndrome (AIDS) or AIDS-related complex (ARC) who were intolerant to zidovudine because of neutropenia, we performed a randomized, open-label study in which patients were assigned to one of two groups. Zidovudine was discontinued in group A patients before instituting GM-CSF treatment and was restarted in a graduated fashion over 4 weeks. Group B patients continued on full-dose (1,200 mg/d) zidovudine therapy while beginning GM-CSF therapy. A total of 17 patients were entered, eight in group A and nine in group B. Five of eight patients in group A and seven of nine in group B had a history of Pneumocystis carinii pneumonia (PCP). All were homosexual males, except one female in group A who was the sex partner of a bisexual male with AIDS. All patients had neutropenia (absolute neutrophil count [ANC] less than 1,000/microL) while taking full-dose zidovudine. The mean CD4 (+/- SD) lymphocyte level was 37 (+/- 29)/microL and 39 (+/- 44)/microL in groups A and B, respectively. After randomization, patients were begun on subcutaneous GM-CSF at a dose of 1.0 microgram/kg/d. Patients in group A received 2 weeks of daily GM-CSF, at which time zidovudine was restarted if the ANC was greater than 1,000/microL; if the ANC was less than 1,000/microL, the dose of GM-CSF was increased to 3.0 micrograms/kg, and at 2-week intervals either zidovudine was restarted or the dose of GM-CSF was increased to 5 micrograms/kg and then 10 micrograms/kg, to maintain the ANC greater than 1,000/microL. Group B patients received full-dose zidovudine concurrently with GM-CSF administration. The dose of GM-CSF was increased every 2 weeks if necessary to keep the ANC greater than 1,000/microL while maintaining full-dose zidovudine therapy. Patients in each group showed an increase in total white blood cell (WBC) count. Neutrophils and eosinophils were responsible for the majority of this increase. Patients in group A had a more rapid increase in WBC than those in group B; however, by week 8, the WBC in each group was essentially equal. Viral replication as measured by human immunodeficiency virus (HIV) p24 antigen (Ag) was decreased in four patients in each group, increased in one patient in each group, and remained unchanged in the remainder. The ability to culture virus from peripheral blood mononuclear cells was not changed by the regimen. The major toxicities of the regimen were fever and malaise.(ABSTRACT TRUNCATED AT 400 WORDS)

AIDS-Related Complex↗
PubMed1991

Antiretroviral therapy and immunomodulators in patients with AIDS.

A number of studies have illustrated the effectiveness of hematopoietic growth factors in managing treatment-related cytopenias in patients with human immunodeficiency virus (HIV) infection. One of these factors, granulocyte-macrophage colony-stimulating factor, has been shown to restore absolute neutrophil counts in patients with acquired immunodeficiency syndrome (AIDS) and Kaposi's sarcoma receiving a combination of zidovudine (AZT) and interferon alfa. A combination of granulocyte colony-stimulating factor and erythropoietin has also been demonstrated to alleviate both neutropenia and anemia in patients with advanced AIDS or AIDS-related complex receiving zidovudine. Hematopoietic growth factors, in combination with each other and with antiretroviral agents, thus have an important supportive role to play in the treatment of patients with HIV disease.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Human immunodeficiency virus infection of megakaryocytic cells.

The human immunodeficiency virus (HIV) is capable of infecting certain cells of hematopoietic lineage, particularly monocyte-macrophages and T lymphocytes. Recently, the possibility that cells of megakaryocytic lineage are susceptible to HIV infection has been raised. We have characterized infection of the permanent megakaryocytic cell line CMK by HIV in vitro. CMK cells were easily infected by HIV type 2 (HIV-2), producing significant amounts of virus in culture. Infection appeared to be mediated by the CD4 surface antigen on CMK cells. Three different strains of HIV-1 were able to minimally infect CMK cells, suggesting there may be isolates of HIV tropic for megakaryocytes. Infection of CMK cells led to downregulation of the CD4 surface antigen but no discernable change in expression of megakaryocyte-associated proteins glycoprotein Ib and glycoprotein IIb/IIIa. These observations support the likelihood that megakaryocytes are susceptible to HIV infection, and cell lines of megakaryocytic origin may provide a useful model to study effects of the retrovirus on megakaryocyte function.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Phase I study of 2'-3'-dideoxyinosine administered orally twice daily to patients with AIDS or AIDS-related complex and hematologic intolerance to zidovudine.

PURPOSE: To evaluate the safety and hematologic tolerance of 2'-3'-dideoxyinosine (didanosine, ddI) in subjects with acquired immunodeficiency syndrome (AIDS) or AIDS-related complex and prior hematologic intolerance to zidovudine. PATIENTS AND METHODS: A Phase I trial with two dose groups at a single-center, university-affiliated hospital ambulatory care center. Of 30 subjects enrolled, 21 had AIDS and nine had AIDS-related complex. All had CD4 lymphocyte counts less than 0.2 x 10(9)/L at entry. Didanosine was administered orally twice daily at a total daily dose of 750 mg or 1,500 mg for 12 weeks. Subjects who completed the 12-week study continued to receive ddI at the lower dose. All subjects were monitored for toxicity. Virologic and immunologic response markers were also measured. RESULTS: For the group as a whole, there was no significant decrease in mean hemoglobin level or leukocyte or platelet counts. The dose-limiting toxicity was peripheral neuropathy. Other significant toxicities included pancreatitis and hypocalcemia. Uric acid elevations were common but were without clinical consequence. A sustained decrease in serum p24 antigen of at least 50% was noted in 42% of subjects who were p24 antigen-positive at entry. The mean CD4 lymphocyte count showed an initial increase that was not sustained over the 12-week study. All subjects remained anergic to skin testing. CONCLUSIONS: Didanosine is well tolerated hematologically in some patients with prior significant hematologic intolerance to zidovudine. The toxicity profile for ddI differs from that of zidovudine and includes peripheral neuropathy and pancreatitis. Changes in CD4 lymphocyte number and HIV p24 antigen levels in some patients suggest antiviral activity of ddI in this population.

AIDS-Related Complex↗
PubMed1991

GM-CSF as an alternative to dose modification of the combination zidovudine and interferon-alpha in the treatment of AIDS-associated Kaposi's sarcoma.

Combined zidovudine (ZDV) and interferon-alpha (IFN) is an appealing therapy for AIDS-associated Kaposi's sarcoma because of the antiretroviral as well as antitumor potential of this combination. Overlapping myelotoxicity of these agents, however, frequently complicates their clinical use. This phase I/II study was undertaken to test the safety and efficacy of granulocyte-macrophage colony stimulating factor (GM-CSF) in those patients who became neutropenic while receiving ZDV (1,200 mg/day) and IFN (9 MU/day). Despite a "high-risk" population of patients, the tumor response rate among evaluable patients was 50% (33% overall). Sixty-four percent of patients required GM-CSF and all patients receiving GM-CSF had a prompt improvement in their absolute neutrophil count (ANC). The use of GM-CSF was associated with an improved end of study ANC (p less than 0.05), but was not associated with tumor response, CD4 count improvement, or improved change in hemoglobin concentration. GM-CSF/ZDV/IFN was not associated with increased toxicity over ZDV/IFN; however, two unusual events occurred in the GM-CSF/ZDV/IFN group: erythema multiforme and glucose intolerance. Dose-limiting thrombocytopenia and anemia were seen in two patients and anemia in one patient on GM-CSF/ZDV/IFN. No consistent alterations in serum HIV p24 antigenemia were noted in either group. The use of GM-CSF mitigated the neutropenia of combined ZDV and IFN. Further study evaluating the utility of this hematopoietic growth factor in combination therapies for AIDS patients is warranted.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Interferon-alpha 2a in the treatment of acquired immunodeficiency syndrome-related Kaposi's sarcoma.

In a series of studies, recombinant interferon-alpha 2a (rIFN alpha 2a, Roferon-A) was administered alone (273 men) or combined with vinblastine (91 men) to patients with acquired immunodeficiency syndrome (AIDS)-related Kaposi's sarcoma (KS). Patients were treated with daily doses of rIFN alpha 2a ranging from 3 to 54 million international units (I.U.) administered intramuscularly. A dose of 36 million I.U. daily for approximately 10 weeks followed by a three times weekly maintenance schedule with the same dose resulted in the best overall therapeutic benefit. An escalating-dose regimen of 3, 9, and 18 million I.U. daily, each for 3 days, followed by 36 million I.U. daily, produced equivalent therapeutic benefit with amelioration of acute toxicity in some patients. Response was more likely in patients without a history of opportunistic infection or B symptoms (fever, night sweats, or weight loss). Response rate increased with increasing baseline CD4 lymphocyte count and was 45.5% in patients with a CD4 count of greater than 400/mm3. Responding patients with a CD4 count of greater than 200/mm3 had a distinct survival advantage over patients who had similar CD4 counts but whose tumors did not regress with therapy. The addition of vinblastine increased toxicity and did not improve the response rate or prolong survival. Side effects included fatigue, fever, chills, myalgias, headaches, anorexia, nausea, diarrhea, and dizziness. Mild abnormalities in hematologic and liver function tests occurred in some patients. Most adverse effects diminished or resolved with continued therapy. We conclude that rIFN alpha 2a offers important therapeutic benefit in a select group of patients with AIDS-related KS.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Phase 1 study of recombinant human CD4-immunoglobulin G therapy of patients with AIDS and AIDS-related complex.

The safety and pharmacokinetics of recombinant CD4-immunoglobulin G (rCD4-IgG) were evaluated in a phase 1 study with dose escalation. A total of 16 patients, 6 with AIDS and 10 with AIDS-related complex, were evaluated at two university-affiliated hospital clinics. rCD4-IgG was administered once weekly for 12 weeks to four patients each at doses of 0.03, 0.1, 0.3, and 1.0 mg/kg of body weight. Dosing was intravenous for two patients in the 1.0-mg/kg dose group and intramuscular for the remaining patients. Dosing was intravenous for two patients in the 1.0-mg/kg dose group and intramuscular for the remaining patients. Pharmacokinetic, toxicity, and immunologic variables were monitored with all patients. Administration of rCD4-IgG was well tolerated, with no important clinical or immunologic toxicities noted. No subjects required dose reduction or discontinuation of therapy due to toxicity. No consistent changes were seen in human immunodeficiency virus antigen levels in serum or CD4 lymphocyte populations. The volume of distribution was small, and compared with that of rCD4, the half-life of the hybrid molecule was markedly prolonged following intramuscular or intravenous administration. The rate and extent of absorption following intramuscular dosing were variable. Intramuscular administration of rCD4-IgG appears to be inferior to intravenous dosing from a pharmacokinetic standpoint, with lower peak concentrations and variable absorption. After intravenous administration, peak concentrations of rCD4-IgG in serum (20 to 24 micrograms/ml) that have shown antiviral activity in vitro against more sensitive clinical isolates of human immunodeficiency virus were achieved. The peak concentrations in serum after intramuscular administration were below these levels. Treatment with rCD4-IgG was well tolerated at the doses administered to patients in this study but did not result in significant changes in CD4 lymphocyte counts or p24 antigen levels in serum.

AIDS-Related Complex↗
PubMed1991

Alternative pathway for induction of human immunodeficiency virus gene expression: involvement of the general transcription machinery.

Human immunodeficiency virus type 1 (HIV-1) is viable and mitogen inducible in the absence of its binding sites for the inducible transcription factor NF-kappa B. We have investigated alternative mechanisms for induction of HIV-1 transcription. Using transient transfection assays, we found that transcription from an HIV-1 LTR containing mutant kappa B sites was activated 10- to 20-fold in a variety of human cell types by the phorbol ester phorbol myristate acetate (PMA). The promoter elements conferring this inducibility were localized to the region downstream of nucleotide -70, which contains the TATA and TAR elements and binding sites for transcription factors Sp1 and LBP-1. Synthetic promoters containing only Sp1 sites and a TATA element were also induced in transfection experiments as well as in in vitro transcription experiments with T-cell nuclear extracts. Moreover, promoters containing a TATA box in the absence of Sp1 sites or Sp1 sites in the absence of a TATA box were equally inducible in vitro, as was an RNA polymerase III promoter. The activities of RNA polymerases II and III and of the 38-kDa TATA-binding protein transcription factor IID (TFIID), were not induced by PMA, but electrophoretic mobility shift assays revealed a highly inducible protein-DNA complex that interacted specifically with the TATA sequence. This protein-DNA complex appeared to be much larger than that found with the 38-kDa human TFIID expressed in bacteria. Taken together, these data suggest that a component of the general transcription machinery, and possibly a TFIID-associated protein, is induced in T cells by PMA.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Granulocyte-macrophage colony-stimulating factor mitigates the neutropenia of combined interferon alfa and zidovudine treatment of acquired immune deficiency syndrome-associated Kaposi's sarcoma.

The combined use of zidovudine (ZDV) and interferon (IFN) alfa-2a has been shown to have antiretroviral and antitumor potential benefit in the treatment of acquired immune deficiency syndrome (AIDS)-associated Kaposi's sarcoma (KS). However, the clinical use of this combination is frequently complicated by the overlapping myelotoxicity of these agents. We report here the results of a phase I/II study in which granulocyte-macrophage colony-stimulating factor (GM-CSF) was used for those KS patients who became neutropenic while receiving ZDV (1,200 mg/d) and IFN (9 x 10(6) U/d). Nineteen of 29 patients (66%) developed an absolute neutrophil count (ANC) of less than 1,000 cells per cubic millimeter and were begun on GM-CSF. All experienced a prompt increase in the ANC. Those patients receiving GM-CSF/ZDV/IFN alfa-2a had an improved end of study ANC when compared with the ZDV/IFN alfa-2a group, but did not have an increased rate of tumor response, end of study CD4 cell count, or improvement in any other hematologic variable. The use of GM-CSF was not associated with increased toxicity and, in particular, was not associated with a change in serum human immunodeficiency virus (HIV) p24 antigen. Tumor response was noted in 50% of the assessable patients (33% overall) despite "high-risk" characteristics in 80%. Of the responding patients, seven were on GM-CSF and might have otherwise required an alteration in ZDV/IFN alfa-2a dose level. Further study of GM-CSF as an alternate to dose modification of this (ZDV/IFN alfa-2a) and other combination therapies for AIDS patients is warranted.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Purified recombinant CD4 inhibits HIV-1 infection of peripheral blood macrophages.

Purified recombinant soluble CD4 (rCD 4) is a new antiviral agent which has been shown to block HIV infection of lymphocytic and monocytic cell lines as well as peripheral blood mononuclear cells. The authors investigated here the ability of rCD4 to inhibit HIV-1 infection of peripheral blood macrophages. In this system, purified preparations of rCD4 provided, at concentrations above 10 micrograms/ml, a complete protection against a challenge with the monocytotropic strain HIV-1 Ba-L. Also, anti-CD 4 monoclonal antibodies directed at the V1 domain of the CD 4 molecule blocked infection of macrophages by HIV. Recombinant CD 4 is therefore a potent antiviral agent able to prevent HIV-1 infection of peripheral blood macrophages, and the CD 4 molecule is likely to be the main HIV receptor on these cells.

Antibodies, Monoclonal↗