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Biomedical subjects

J A Thompson

Publications and source records attributed to J A Thompson.

At least 217 records · Page 12Linked to original sources
PubMed1989

Lymphokine-activated killer function following autologous bone marrow transplantation for refractory hematological malignancies.

Disease recurrence remains the major factor which limits the success of autologous bone marrow transplantation (ABMT) for refractory hematological malignancies. The administration of interleukin 2 (IL2) with or without ex vivo generated lymphokine-activated killer (LAK) cells represents a potential approach to eradicating residual disease after ABMT. However, since LAK precursor activity is radiosensitive, high dose chemoradiotherapy may abrogate LAK function and preclude clinical responsiveness to IL2 after ABMT. Furthermore, since lymphocyte subsets which mediate LAK activity may recover at different rates after ABMT, LAK cells may be phenotypically and/or functionally altered after ABMT. To determine whether IL2 responsive LAK precursor cells are present in the circulation after ABMT, peripheral blood mononuclear cells (PBMC) from 21 patients with acute leukemia or lymphoma were tested for IL2-inducible LAK activity 17-83 days after ABMT. Cells were cultured with IL2 (1000-2000 units/ml) for 4 or 5 days and then tested for cytolytic activity and/or cell phenotype. LAK activity against the Daudi cell line was detected in every PBMC sample from every patient at every time point tested. The Raji cell line and a fresh allogeneic ovarian carcinoma were also lysed by LAK cells generated after ABMT. In the subgroup of patients transplanted for non-Hodgkin's lymphoma, LAK precursor activity appeared comparable to that of healthy controls. Culture with IL2 resulted in increased mean IL2 receptor expression in lymphocytes from patients after ABMT (3.1-9.9%) and from healthy controls (3.1-12.0%). After culture with IL2, the percentage of cells bearing the natural killer cell-associated Leu-19 determinant was significantly higher in patient PBMC than in normal control PBMC (28.3 versus 8.7%). Positive and negative cell selection by fluorescence sorting after culture with IL2 revealed that most of the LAK activity after ABMT was mediated by the Leu-19+ cells. Although CD5+ T-cells were devoid of LAK activity, a subset LAK effectors was CD8+. Thus, LAK activity is rapidly reconstituted after ABMT and is mediated by cells phenotypically similar to those in normal controls. These results support the feasibility of IL2 +/- LAK as consolidative immunotherapy after ABMT.

Antigens, CD↗
PubMed1989

cDNA cloning demonstrates the expression of pregnancy-specific glycoprotein genes, a subgroup of the carcinoembryonic antigen gene family, in fetal liver.

The pregnancy-specific glycoprotein (PSG) genes constitute a subgroup of the carcinoembryonic antigen (CEA) gene family. Here we report the cloning of four cDNAs coding for different members of the PSG family from a human fetal liver cDNA library. They are derived from three closely related genes (PSG1, PSG4 and PSG6). Two of the cDNA clones represent splice variants of PSG1 (PSG1a, PSG1d) differing in their C-terminal domain and 3'-untranslated regions. All encoded proteins show the same domain arrangement (N-RA1-RA2-RB2-C). Transcripts of the genes PSG1 and PSG4 could be detected in placenta by hybridization with gene-specific oligonucleotides. Expression of cDNA in a mouse and monkey cell line shows that the glycosylated PSG1a protein has a Mr of 65-66 kD and is released from the transfected cells. Sequence comparisons in the C-terminal domain and the 3'-untranslated regions of CEA/PSG-like genes suggests a complex splicing pattern to exist for various gene family members and a common evolutionary origin of these regions.

Amino Acid Sequence↗
PubMed1989

Very low dose alpha-2b interferon for the treatment of hairy cell leukemia.

Alpha-2b interferon (alpha-2b IFN), administered at 2 x 10(6) U/m2 three times per week is highly effective in the treatment of progressive hairy cell leukemia (HCL) and in the retreatment of patients who have relapsed after previous IFN therapy. To determine if a lower interferon dose would induce a comparable antileukemic effect with less toxicity, a-2b IFN was administered at 2 x 10(5) U/m2 subcutaneously three times per week to 17 patients with progressive HCL. Thirteen patients had HCL in relapse after a previous response to alpha-2b IFN; four patients were previously untreated. The median duration of treatment was 9 months. Toxicity consisted only of transient, mild flu-like symptoms in two patients. Of the 13 previously IFN-treated patients, four had a minimal response, one had no response, and eight had progressive disease. Of four previously untreated patients, one had a partial response, two had a minimal response, and one had no response. In seven of eight patients whose disease progressed on low-dose IFN, the dose was escalated to 2 x 10(6) U/m2 three times per week, and all seven patients demonstrated hematologic response within 3 months to the dose escalation. We conclude that alpha-2b IFN at 2 x 10(5) U/m2 three times per week is relatively ineffective for the treatment of relapse after previous IFN therapy.

Dose-Response Relationship, Immunologic↗
PubMed1989

Identification of a carcinoembryonic antigen gene family in the rat. Analysis of the N-terminal domains reveals immunoglobulin-like, hypervariable regions.

The existence of a carcinoembryonic antigen (CEA)-like gene family in rat has been demonstrated through isolation and sequencing of the N-terminal domain exons of presumably five discrete genes (rnCGM1-5). This finding will allow for the first time the study of functional and clinical aspects of the tumor marker CEA and related antigens in an animal model. Sequence comparison with the corresponding regions of members of the human CEA gene family revealed a relatively low similarity at the amino acid level, which indicates rapid divergence of the CEA gene family during evolution and explains the lack of cross-reactivity of rat CEA-like antigens with antibodies directed against human CEA. The N-terminal domains of the rat CEA-like proteins show structural similarity to immunoglobulin variable domains, including the presence of hypervariable regions, which points to a possible receptor function of the CEA family members. Although so far only one of the five rat CEA-like genes could be shown to be transcriptionally active, multiple mRNA species derived from other members of the rat CEA-like gene family have been found to be differentially expressed in rat placenta and liver.

Amino Acid Sequence↗
PubMed1989

Analysis of the size of the carcinoembryonic antigen (CEA) gene family: isolation and sequencing of N-terminal domain exons.

Five members of the human CEA gene family [human pregnancy-specific beta 1-glycoprotein (PS beta G); hsCGM1, 2, 3 and 4] have been isolated and identified through sequencing the exons containing their N-terminal domains. Sequence comparisons with published data for CEA and related molecules reveal the existence of highly-conserved gene subgroups within the CEA family. Together with published data eleven CEA family members have so far been determined. Apart from the highly conserved coding sequences, these genes also show strong sequence conservation in their introns, indicating a duplication of whole gene units during the evolution of the CEA gene family.

Amino Acid Sequence↗
PubMed1989

Influence of schedule of interleukin 2 administration on therapy with interleukin 2 and lymphokine activated killer cells.

The purpose of this study was to compare the toxicity, immunomodulatory changes, and antitumor efficacy of interleukin 2 (IL-2) and lymphokine activated killer (LAK) cell therapy with two durations of IL-2 infusion. Patients with progressive melanoma, non-Hodgkin's lymphoma, renal carcinoma, or colon carcinoma received IL-2 at 3 X 10(6) units/m2/day on days 1-5 and 13-17, either by bolus injection every 8 h (q8h) or by continuous i.v. (CIV) administration. Peripheral blood mononuclear cells were harvested by leukapheresis on days 8, 9, and 10, were incubated in vitro for 5 days for generation of LAK cells, and were infused on days 13, 14, and 15. The first 11 patients were treated with IL-2 q8h, and the subsequent 13 patients were treated by CIV infusion. Toxicity consisted primarily of fever, chills, emesis, diarrhea, weight gain, and edema but did not require intensive care unit support and did not differ significantly between treatment groups. IL-2-induced lymphocytosis on day 8 was higher with CIV than with q8h administration with a mean lymphocyte count/microliter of 5610 +/- 700 (SE) versus 3300 +/- 500. Immunomodulatory changes observed on days 8 and 20 were also greater with CIV IL-2 and included an increase in peripheral blood mononuclear cell IL-2 receptor expression as well as a marked rise in the number of Leu-11+ and Leu-19+ peripheral blood mononuclear cells. The total leukapheresis yield per patient and total number of LAK cells infused per patient were higher with CIV than q8h administration, with 49.8 +/- 4.9 X 10(9) versus 39.4 +/- 5.4 X 10(9) and 42.6 +/- 5.0 X 10(9) versus 34.0 +/- 5.4 X 10(9), respectively. The cells infused displayed phenotypic evidence of activation and exhibited marked lytic reactivity to Daudi, Raji, and HT-144 targets. One complete and one minimal response were observed in 2 of 8 patients with metastatic renal cell carcinoma who received CIV IL-2 and LAK cells. The results show that IL-2 is more biologically active by CIV than q8h administration, as demonstrated by greater rebound lymphocytosis, LAK cell yield, and in vivo immunostimulation.

Adult↗
PubMed1989

Gene expression in implanted rat hepatocytes following retroviral-mediated gene transfer.

An hepatocyte transplantation-gene transfer protocol has been developed whereby liver cells containing an expressing NeoR gene can be successfully implanted in vivo. Adult primary cultures of rat hepatocytes, after infection with the retroviral vector N2, were grown on a floating solid support (coated with purified collagen IV) in a serum-free hormonally defined medium designed for hepatocytes that also contained G418. Under these conditions, normal adult hepatocytes expressing the NeoR gene could be grown to high density. The solid supports holding the gene-engineered hepatocytes were then implanted into adult rats into subcutaneous and intraperitoneal sites. After one to two weeks, the supports were removed and shown to still contain the gene-engineered hepatocytes expressing the NeoR gene. These results suggest that cells from solid organs, such as the liver, are potential targets for gene transfer and expression studies in vivo.

Animals↗
PubMed1989

Intra- and interspecies analyses of the carcinoembryonic antigen (CEA) gene family reveal independent evolution in primates and rodents.

Various rodent and primate DNAs exhibit a stronger intra- than interspecies cross-hybridization with probes derived from the N-terminal domain exons of human and rat carcinoembryonic antigen (CEA)-like genes. Southern analyses also reveal that the human and rat CEA gene families are of similar complexity. We counted at least 10 different genes per human haploid genome. In the rat, approximately seven to nine different N-terminal domain exons that presumably represent different genes appear to be present. We were able to assign the corresponding genomic restriction endonuclease fragments to already isolated CEA gene family members of both human and rat. Highly similar subgroups, as found within the human CEA gene family, seem to be absent from the rat genome. Hybridization with an intron probe from the human nonspecific cross-reacting antigen (NCA) gene and analysis of DNA sequence data indicate the conservation of noncoding regions among CEA-like genes within primates, implicating that whole gene units may have been duplicated. With the help of a computer program and by calculating the rate of synonymous substitutions, evolutionary trees have been derived. From this, we propose that an independent parallel evolution, leading to different CEA gene families, must have taken place in, at least, the primate and rodent orders.

Animals↗
PubMed1989

Evidence for a role of tert-butyl hydroxylation in the induction of pneumotoxicity in mice by butylated hydroxytoluene.

Previous studies have shown that BHT must be biotransformed, probably to a quinone methide, in order to cause pneumotoxicity in mice. When BHT is incubated with mouse hepatic or pulmonary microsomes, a major metabolite that is formed is the tert-butyl-hydroxylated derivative of BHT (BHT-BuOH). Herein we show that BHT-BuOH has a fourfold greater potency than BHT in increasing the lung wt/body wt ratio, decreases lung cytosolic Ca2+-dependent protease activity at 1/10 the dose required for BHT to do this, and causes pulmonary histopathology at 1/20 the dose of BHT. Lung damage occurs earlier and is repaired faster at lower concentrations of BHT-BuOH than of BHT, but the nature of the damage (type I cell death) and regenerative response (type II cell hyperplasia and differentiation) is apparently identical. Neither BHT-BuOH nor BHT cause damage to liver, kidney, or heart as assessed by light microscopy, so they are both specific pulmonary toxicants. We postulate that BHT-BuOH formation is an essential step in the conversion of BHT to the ultimate pneumotoxin, which might be the corresponding quinone methide.

Animals↗
PubMed1989

Heparin-binding growth factor 1 induces the formation of organoid neovascular structures in vivo.

One of the promises of modern molecular biology has been the opportunity to use genetically modified human cells in a patient to permanently restore inborn errors of metabolism. Although it has been possible to introduce genes into mammalian cells and to control their expression, it has proven difficult to introduce mammalian cells as carriers of the modified genetic information into hosts. The successful implantation of selective cells cannot be achieved without adequate vascular support, an essential step toward integration and reconstitution of a new biological function. Although a partial solution to this problem has been found by inducing specific site-directed neovessel formation using heparin-binding growth factor 1 (HBGF-1) adsorbed to a collagen matrix, these implants function for only a short period (weeks). We now report the formation of organoid neovascular structures using polytetrafluoroethylene fibers coated with collagen and HBGF-1 implanted in the peritoneal cavity of the rat. The organoid structures contained readily visible vascular lumina and nonvascular structures that resemble nerve tissue. It was also possible to demonstrate that the vascular system on the implant is continuous with the vascular tree of the host. This feature was used to demonstrate that the organoid structures are capable of sustaining the biological function of implanted normal rat hepatocytes over long periods of time (months) in the homozygous Gunn rat, thereby facilitating future applications involving the delivery of new genetic information.

Animals↗
PubMed1989

A metabolite of butylated hydroxytoluene with potent tumor-promoting activity in mouse lung.

Chronically administered butylated hydroxytoluene (BHT) can enhance the formation of carcinogen-induced lung tumors in mice, and biotransformation of BHT is required for this activity. In the present study, oxidative metabolism of BHT by liver microsomes and lung tumor promotion by BHT in three inbred mouse strains, NGP/N, A/J and MA/MyJ, were compared. The strain order shown is the order of increasing susceptibility of these mice to BHT tumor promotion which correlates with their increasing ability to produce a particular metabolite, BHT-BuOH, by hydroxylation of BHT at one of the tert-butyl groups. Chronic BHT administration, according to the treatment regimen for promotion, selectively induced the BHT oxidization pathway leading to BHT-BuOH. The results suggest that formation of BHT-BuOH leads to the tumor promoting effects of BHT. This hypothesis was tested directly by chronic administration of BHT, BHT-BuOH, and two other metabolites, 2,6-di-tert-butyl-4-hydroxymethyl phenol and 2,6-di-tert-butyl-1,4-benzoquinone to MA/MyJ mice following a single injection of urethane. The only metabolite that enhanced lung tumor formation was BHT-BuOH, and it was effective at one-fourth the effective dose of BHT. Thus both indirect and direct evidence implicates BHT-BuOH formation as an important step in the chain of events leading to promotion of lung tumors.

Animals↗
PubMed1989

Radionuclide detection of abnormal ventricular filling patterns in rejecting human allografts.

Parameters of systolic and diastolic function obtained from radionuclide ventriculography (RNV) were evaluated in nine cardiac allograft recipients. In 25 examinations, left end-diastolic volume (LEDV), cardiac output (CO), left ejection fraction (LEF), right ejection fraction (REF), heart rate (HR), peak filling rate (PFR), time to peak filling rate (TPFR), peak ejection rate (PER), and average filling rate for the first half of diastole (DFRH) were determined. Endomyocardial biopsy was obtained within 48 hours. Biopsies were divided into three treatment classes (0 = normal; 1 = rejection but not requiring supplemental therapy; and 2 = rejection requiring supplemental immunotherapy). Two independent variables of diastolic function proved to be significant (DFRH P less than 0.00001, and PFR P less than 0.002) predictors of the dependent variable class when regression analysis was applied to the data. Alterations in diastolic function associated with acute rejection are detectable on RNV and simulate changes anticipated in a primary restrictive cardiomyopathy.

Adolescent↗
PubMed1989

Subcutaneous granulocyte-macrophage colony-stimulating factor in patients with myelodysplastic syndrome: toxicity, pharmacokinetics, and hematological effects.

The toxicity, pharmacokinetics, and hematologic effects of granulocyte-macrophage colony-stimulating (GM-CSF) were studied in a phase I/II trial of 16 patients with myelodysplastic syndrome (MDS). The GM-CSF was administered subcutaneously (SC) daily so as to achieve prolonged blood levels and to establish an outpatient treatment regimen. Four dose levels were administered for ten days: 0.3 microgram/kg/d (three patients), 1.0 microgram/kg/d (three), 3.0 micrograms/kg/d (four), and 10.0 micrograms/kg/d (six). The most common toxicities were fever and a flu-like syndrome, which were dose-dependent. The maximum-tolerated dose was 10.0 micrograms/kg/d, which induced severe rigors (two patients), fever greater than 40 degrees C (one), severe bronchospasm (one), and WBC 60,000 (one). In one patient, refractory anemia with excess blasts in transformation (RAEB-T) progressed to acute nonlymphocytic leukemia after two doses of GM-CSF, and the patient died of leukemia that did not respond to chemotherapy. After doses of 3.0 and 10.0 micrograms/kg, serum GM-CSF levels peaked at 3.8 to 6.3 hours, and persisted for 14 and 24 hours, respectively. Circulating granulocytes (neutrophils and bands) increased in a dose-dependent manner, as 11 of 13 patients who received greater than or equal to 1.0 microgram/kg/d responded with a two- to 194-fold increase. Although the neutrophils usually returned to pretreatment levels shortly after stopping GM-CSF, two patients continue to exhibit an elevation of neutrophils for 6 months. Dose-related increases in circulating monocytes and eosinophils were also noted. Transient increases in platelet and reticulocyte counts were observed in two and three patients, respectively. Five of the 16 patients later received maintenance GM-CSF at 3 micrograms/kg/d for 2 to 9 weeks. All showed a dramatic increase in neutrophils after 2 weeks. Thereafter, despite continued therapy, the neutrophil count in four patients declined markedly. In conclusion, GM-CSF is well tolerated by the SC route and induces striking, but usually temporary, improvement in the neutropenia of MDS. Larger prospective phase III trials will determine the duration of hematologic responses and the impact on infection, morbidity, and mortality.

Adolescent↗
PubMed1988

Site-directed neovessel formation in vivo.

Angiogenesis is an important component of organogenesis and wound repair and occurs during the pathology of oncogenesis, atherogenesis, and other disease processes. Thus, it is important to understand the physiological mechanisms that control neovascularization, especially with methods that permit the molecular dissection of the phenomenon in vivo. Heparin-binding growth factor-1 was shown to bind to collagen type I and type IV. When complexed with gelatin, heparin-binding growth factor-1 can induce neovascularization at polypeptide concentrations that are consistent with the biological activity of the mitogen in vitro. The adsorption strategy induces rapid blood vessel formation at and between organ- and tissue-specific sites and permits recovery of the site-specific implant for examination and manipulation by molecular methods.

Animals↗
PubMed1988

Identification of a downstream sequence and binding protein that regulate adenovirus major late promoter transcription in vitro.

Gel electrophoresis mobility shift and DNase I footprint assays detect a cellular nuclear protein in extracts made from uninfected human cells which binds to a downstream promoter sequence (DPS) in the human adenovirus 2 major late promoter. By DNase I footprint and mutation analyses, we have determined that this new regulatory element extends from positions +146 to +165 (relative to the cap site at position +1). We show by UV cross-linking that a 40-kDa polypeptide specifically binds to this region. Mutations within the DPS which decrease protein binding by 80-90% also cause a 2.5-3-fold decrease in in vitro major late promoter transcription efficiency. Alteration of the template in the 5'-flanking region of the DPS does not affect nuclear protein binding or transcription efficiency. Interestingly, a T----G transversion at position +160 which increases protein binding also impairs promoter activity.

Adenoviruses, Human↗