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Biomedical subjects

G G Steger

Publications and source records attributed to G G Steger.

At least 55 records · Page 3Linked to original sources
PubMed1995

The effects of granulocyte-macrophage colony-stimulating factor on tumour-infiltrating lymphocytes from renal cell carcinoma.

It has been shown that granulocyte-macrophage colony-stimulating factor (GM-CSF) can induce specific and non-specific anti-tumour cytotoxicity and also stimulates the proliferation and function of peripheral lymphocytes and thymocytes. GM-CSF and interleukin 2 (IL-2) act synergistically on peripheral lymphocytes for the induction of a highly effective cytotoxic cell population. Thus, the goal of our investigation was to study the effects of GM-CSF upon expansion, proliferation and in vitro killing activity of tumour-infiltrating lymphocytes (TILs) from renal cell carcinoma (RCC). TILs from seven consecutive tumours were cultured with GM-CSF (500 or 1000 nmol ml-1) without IL-2 supplementation, with suboptimal doses of IL-2 (8 and 40 U ml-1) plus GM-CSF (1000 nmol ml-1), and with a dose of IL-2 (400 U ml-1) which sufficed alone to induce TIL development plus GM-CSF (500 or 1000 nmol ml-1). GM-CSF alone or together with suboptimal doses of IL-2 was not able to induce or facilitate TIL development in these cultures. When GM-CSF at both concentrations studied was added to optimal doses of IL-2 the resulting TIL populations proliferated significantly better and faster (+66%), resulting in a higher cell yield (+24%) at the time of maximal expansion of the TIL cultures. The length of the culture periods of TILs was not affected by GM-CSF when compared with the control cultures supplemented with IL-2 alone. In vitro killing activity of TIL populations stimulated with IL-2 and GM-CSF remained unspecific, but lysis of the autologous tumour targets as well as the allogeneic renal tumour targets was significantly enhanced (+138%) as compared with the corresponding control TILs stimulated with IL-2 alone. Lysis of the natural killer (NK)-sensitive control cell line K562 and the NK-resistant Daudi cell line remained unchanged even though FACS analysis of TILs cultured with IL-2 and 1000 nmol of GM-CSF demonstrated a significantly higher proportion of cells expressing the CD56 molecule (+50%). Specific receptors for GM-CSF could not be demonstrated on TILs from RCC. Our data demonstrate that GM-CSF alters the biological behaviour of IL-2-activated TILs from renal cell carcinoma in terms of proliferation, in vitro killing activity and cell-surface molecule expression.(ABSTRACT TRUNCATED AT 400 WORDS)

Carcinoma, Renal Cell↗
PubMed1995

Stereospecific pharmacokinetics of rac-5-methyltetrahydrofolic acid in patients with advanced colorectal cancer.

1. The pharmacokinetics and toxicity of racemic 5-methyltetrahydrofolic (rac-5-MTHF) acid after i.v. infusion were investigated in 18 patients with advanced colorectal cancer. Doses of 100-600 mg rac-5-MTHF/m2 were administered over 2 h together with a bolus of 500 mg/m2 5-fluorouracil (5-FU) as a midpoint injection. 2. The pharmacokinetics of both diastereoisomers were linear in the range from 100-600 mg 5-MTFH/m2. Independent of the administered dose, the maximal plasma concentration of [R]-5-MTHF was nearly twice that of [S]-5-MTHF. The elimination of [S]-5-MTHF from plasma was considerably faster than that of the [R]-isomer (elimination half-life: 3.1 +/- 1.0 h vs 8.3 +/- 3.2 h). No metabolites were detected in plasma and in urine samples. 3. The plasma protein binding was stereoselective ([R]-5-MTHF bound: 88.2 +/- 2.7%; [S]-5-MTHF bound: 59.9 +/- 6.8%; P < 0.001), causing a significantly higher renal clearance for [S]-5-MTHF when compared with the [R]-isomer (37.5 +/- 23.7 ml min-1 vs 12.7 +/- 11.2 ml min-1, P < 0.001). There was no dose dependence, but gender influenced renal clearance (CLren[R]-5-MTHF: male vs female: 20.5 +/- 14.5 ml min-1 vs 7.8 +/- 4.7 min-1, P = 0.03; CLren [S]-5-MTHF: male vs female: 57.2 +/- 21.7 ml min-1 vs 25.7 +/- 16.2 ml min-1, P = 0.006). 4. Toxic side effects of the combination 5-FU/5-MTHF were rare and generally mild, and included stomatitis, nausea/emesis, diarrhoea, anaemia, leukopenia, and thrombocytopenia. 5. In combination with 500 mg 5-FU/m2 a single dose of 600 mg rac-5-MTHF/m2 can safely be administered to patients with colorectal cancer. A similar therapeutic benefit of 5-MTHF to folinic acid in the biochemical modulation of 5-FU is supported by the comparison of in vitro and in vivo data.

Aged↗
PubMed1994

Different stereospecific protein binding of tetrahydrofolates to human serum albumin.

The protein binding of the tetrahydrofolates folinic acid (FA) and its metabolite 5-methyltetrahydrofolic acid (5-MTHF) to human serum albumin (HSA) is stereoselective. At therapeutically relevant concentrations of tetrahydrofolate (range, 5-100 microM), the protein binding was stereoselective to the (R)-isomers of FA and 5-MTHF. The binding of (R)-FA and (R)-5-MTHF was saturated at a concentration of 7% HSA [(R)-tetrahydrofolate bound, ca. 80%]. In contrast to (S)-FA, which was not bound to HSA, (S)-5-MTHF was bound to 45% under physiological conditions. (R)-FA did not influence the protein binding of (S)-FA. Hypoalbuminemia is common in patients with advanced colorectal cancer and affects differentially the protein binding of the diastereoisomers of FA and 5-MTHF. Thus, an influence on the biochemical modulation of 5-fluorouracil by tetrahydrofolates should be taken into consideration.

Chromatography, High Pressure Liquid↗
PubMed1994

Patterns of cytokine release of unselected and CD8+ selected renal cell carcinoma tumor-infiltrating lymphocytes (TIL). Evidence for enhanced specific killing of tumor necrosis factor-secreting/IL-6 nonsecreting TIL in vitro and correlation with complete response in vivo.

Murine systems have demonstrated improved anti-tumor efficacy when tumor-infiltrating lymphocytes (TIL) are combined with interleukin-2 (IL-2). One goal of human adoptive immunotherapy is to identify and expand TIL with specific activity against autologous tumor. In this study we attempted to isolate and characterize such cells by phenotype and cytokine expression pattern. Fourteen unselected (bulk) TIL and 5 CD8+ selected cultures were established from primary renal cell carcinoma. All cultures were grown in the presence of IL-2; triplicate cultures of each TIL culture were grown in IL-2 alone or were intermittently cocultured with irradiated allogeneic or autologous tumor. The in vitro cytotoxicity, phenotype, and cytokine expression pattern as defined by the secretion of tumor necrosis factor-alpha (TNF-alpha), interferon-gamma, granulocyte-macrophage colony-stimulating factor, IL-4, IL-6, and IL-12 were evaluated for each culture. While there was significant heterogeneity among the cultures under differing culture conditions as characterized by cytotoxicity, phenotype, and cytokine secretion pattern, we identified 8 TIL cultures which demonstrated specific enhanced lysis of only autologous tumor upon exposure to irradiated autologous tumor in vitro. These cultures demonstrate a decreased proportion of cells expressing the phenotype CD11b+. More importantly, these cultures were defined by the cytokine secretion phenotype TNF(+)/IL-6(-) upon exposure to irradiated autologous tumor. When utilized in vivo in adoptive immunotherapy of metastatic renal cell carcinoma together with IL-2, complete resolution of all metastatic tumor has only been achieved in patients who received TIL with the cytokine profile TNF(+)/IL-6(-). These findings suggest that tumor-specific renal TIL with enhanced tumor-specific cytotoxicity can be generated in vitro and can be characterized by a specific pattern of cytokine secretion. In addition, patients who receive TIL characterized by the cytokine profile TNF(+)/IL-6(-) may have an improved outcome when receiving immunotherapy.

CD8 Antigens↗
PubMed1994

Double modulation of 5-fluorouracil by high-dose leucovorin and interferon alpha 2b in advanced colorectal cancer: a phase I and a phase II study of weekly administration.

In an attempt to evaluate the feasibility of 5-fluorouracil (FU) treatment modulated by (R,S)-leucovorin (LV) and interferon alpha (IFN alpha) in patients with advanced colorectal cancer, we conducted a phase I trial with increasing doses of subcutaneous IFN alpha (3 x 1 x 10(6) U, 3 x 3 x 10(6) U, 3 x 3 x 10(6) U, 3 x 5 x 10(6) U and 3 x 10 x 10(6) U/week) and 500 mg/m2 LV i.v. as a 2-h infusion with 600 mg/m2 FU i.v. as a midpoint injection. Unacceptable side-effects occurred in all 3 patients at the highest dose level of IFN alpha, while toxicity was tolerable at 3 x 5 x 5 x 10(6) U IFN alpha/week. Thus, this dose was defined as the maximal tolerable dose for IFN alpha in combination with FU and LV. In a subsequent phase II study a total of 83 treatment courses (median: 2.8, range: 2-10) were administered to 30 evaluable patients. Side-effects were acceptable with no WHO grade IV toxicities. Grade III toxicities consisted in thrombopenia (2/30), stomatitis (2/30), diarrhoea (3/30) and nausea/vomiting (4/30). After a median observation time of 17 months (range: 8-22 months), no complete remission was observed and 9 patients experienced a partial response lasting for a median of 6.6 months (range: 3-13+ months), for an overall response rate of 30% (95% confidence interval: 15%-49%). These results show that the described regiment of FU doubly modulated by LV and IFN alpha is active in colorectal cancer and can be safely administered in an out patient setting with acceptable toxicity. Thus, this regimen is suitable to be used for further evaluation in clinical trials.

Adult↗
PubMed1994

Pharmacokinetics of rac-leucovorin vs [S]-leucovorin in patients with advanced gastrointestinal cancer.

1. The pharmacokinetics of [R]-leucovorin ([R]-LV), [S]-leucovorin ([S]-LV) and the circulating metabolite [S]-5-methyltetrahydrofolate ([S]-5-MTHF) were studied after administration of racemic LV and [S]-LV in 21 subjects. 2. After intravenous infusion of 600 mg m-2 rac-LV (group 1, n = 7) or 300 mg m-2 [S]-LV (group 3, n = 7), the decay of [S]-LV in plasma was biexponential with a distribution half-life of 0.8 to 1 h and an elimination half-life of 11 to 23 h. When rac-LV was administered as a 2 h i.v. infusion (400 mg m-2) following a loading dose of 200 mg m-2 (group 2, n = 7), the plasma concentrations of [R]-LV and [S]-5-MTHF decayed monoexponentially with mean (+/- s.d.) half-lives of 10 +/- 3 h and 7 +/- 2 h, respectively. 3. The AUC of [S]-5-MTHF was significantly higher after infusion of 300 mg m-2 [S]-LV than after infusion of 600 mg m-2 rac-LV (83 +/- 22 micrograms ml-1 h vs 53 +/- 22 micrograms ml-1 h; P = 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Folate absorption in Crohn's disease.

An oral folate absorption test was performed in 100 consecutive patients with Crohn's disease (CD) and 20 healthy individuals to investigate the frequency of abnormal folate absorption in regard to the site of the disease and to investigate the possibility of defining a subgroup of patients requiring parenteral folate supplementation. The described oral folate absorption test can be performed quickly on an outpatient basis and is capable of distinguishing patients with altered folate absorption from those with normal folate absorption. In 25 patients, abnormal folate absorption was detected. 16 patients showed impaired folate absorption as indicated by a marked but insufficient increase in serum folate levels after oral folate intake, whereas no increase of the serum folate levels was detected in the remaining 9 patients. Abnormal folate absorption was not correlated with disease extent or activity. In patients with only impaired folate absorption, it might be sufficient to increase dietary intake of folates. In the remaining patients with no measurable increase of serum folate levels after oral folate intake, i.e. about 10% of all patients with CD, parenteral folate supplementation could be considered.

Administration, Oral↗
PubMed1994

Comparison of an immunoradiometric and an immunoluminometric assay for the evaluation of the tumour associated antigens CA 19-9 and CA 125.

We evaluated the levels of CA 19-9 and CA 125 in the sera of healthy individuals, patients with non-neoplastic diseases known to produce elevated serum concentrations of CA 19-9 and CA 125, and patients with malignant tumours. The serum concentrations determined with an immunoradiometric assay (IRMA) and an immunoluminometric assay (ILMA) were compared. The accuracy was determined (as far as this is possible in the absence of reference method values), as well as the precision (intra-assay variation and inter-assay variation), using internal and external controls. The serum concentrations were comparable in both test systems (coefficient of correlation, Kendall's Tau of CA 19-9: 0.88, p < 0.001; CA 125: 0.87, p < 0.001). The linearity of both assays was excellent when serum samples were diluted (r > 0.98 in all assays tested). The intra-assay variation of CA 19-9 IRMA was less than that of CA 19-9 ILMA, and was comparable for CA 125 in both assays. The coefficients of variation of duplicates were nearly independent of the antigen concentration within the range 20-1000 kU/l (mean CV CA 19-9: 3.7% and 3.9% for IRMA and ILMA, respectively; mean CV CA 125: 3.9% and 5.6% for IRMA and ILMA, respectively). In the assay of external controls, the performance of the IRMAs was found to be slightly better than that of the ILMAs, but it was not satisfactory. We conclude that, with some improvements in quality control, luminescence assays are a possible alternative to isotopic assays in the clinical laboratory.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1994

Karyotype and prognosis in non-Hodgkin lymphoma.

In malignant non-Hodgkin lymphomas (NHL), cytogenetic analysis may provide prognostic information including prediction of histologic evolution and responsiveness to therapy. In this study, we correlate clinical data and chromosomal aberrations in 70 adult patients with newly diagnosed NHL followed for a median of 20 months. Clonal aberrations were detected in 68/70 patients (97%). Besides t(2;5)(p23;q35), observed exclusively in three patients with anaplastic large cell lymphoma, Ki-1 positive, none of the characteristic aberrations observed was specific for a given histological subtype. Aberrations of chromosome 7 (n = 21) occurred in all histological subtypes together with aberrations of chromosome 3 and of the short arm of chromosome 17. They were clinically associated with a high serum lactate dehydrogenase level (LDH) and a trend to short survival. Anomalies of the long arm of chromosome 13 (n = 10) were found in patients with high grade B-cell lymphomas and bulky disease. In t(14;18)(q32;q21) bearing lymphomas (n = 27), distinct patterns of additional aberrations were observed in low grade and high grade lymphomas: trisomy 3 and trisomy 18 occurred concomitantly in high grade lymphomas (n = 6, p < 0.001) as well as aberrations of 1q, 5q, 6q and +der (18)(q21). In conclusion, cytogenetic analysis provides information about the complexity of genetic changes in NHL. These changes act not only as indicators of disease activity, but influence clinical outcome as demonstrated by their stringent correlation to the International Index and might reveal more general rules of tumor growth and spreading.

Adolescent↗
PubMed1993

Determination of methotrexate in human urine at nanomolar levels by high-performance liquid chromatography with column switching.

An high-performance liquid chromatographic method with column switching for the detection of less than 4 ng of methotrexate in the urine of oncologic nurses is described. Urine samples were purified by solid-phase extraction on silica-bonded phenyl columns, eluting impurities with ethyl acetate. After elution from the column, the analyte was concentrated ten-fold, evaporating the solvent. On a strong anion-exchange column (Nucleosil 100 SB), methotrexate was separated from the remaining interfering substances, was then switched to a reversed-phase column (LiChrospher 100 RP-18e), and finally eluted by a linear gradient in a solvent system consisting of ammonium formate buffer (pH 2.7) and acetonitrile. Absorbance was monitored at 310 nm. This method has proved to be suitable for detecting traces of methotrexate in urine in order to individualize risks and to reduce further the occupational safety hazard for hospital personnel.

Bone Neoplasms↗
PubMed1993

GM-CSF in the treatment of a patient with severe methotrexate intoxication.

This case report describes the successful treatment of severe methotrexate intoxication in a 72-year-old female patient. Following two prior uneventful courses of a polychemotherapy regimen including low-dose intravenous (i.v.) methotrexate, the patient presented with fever, polymucositis, incipient pyodermia, acute renal failure and pancytopenia 9 days after the third application. Severe methotrexate overdose was confirmed by serum levels. Using a polypragmatic treatment approach focusing on renal function and including granulocyte-macrophage-colony-stimulating factor (GM-CSF) this life threatening and nearly fatal intoxication was successfully treated. This case report demonstrates that GM-CSF might contribute to rapid reconstitution of leukopoiesis once methotrexate serum levels are in the subtoxic range.

Acute Disease↗
PubMed1991

Instability of the anticancer agent etoposide under in vitro culture conditions.

Degradation of etoposide is rapid under in vitro culture conditions. At pH 7.4 and 37 degrees C, the isomerisation of trans-etoposide to the inactive compound cis-etoposide has a half-life of 2 days in Dulbecco's modified Eagle's medium and results in the loss of 90% of the active drug within 1 week. As a consequence, prolonged incubations with etoposide in in vitro assays may lead to erroneous interpretations ignoring the real in vitro situation. The degradation is not influenced by organic compounds such as bovine serum albumin or amino acids but depends strongly on the pH value and, to a lesser degree, on the ionic strength of the medium. Therefore, we propose a mathematical correction based on the pH value so as to obtain the real exposure of cells to trans-etoposide during in vitro assays.

Cells, Cultured↗
PubMed1991

Complete remission of metastasised clear cell sarcoma of tendons and aponeuroses.

Clear cell sarcoma of tendons and aponeuroses is a rare disorder which originates from migrated neural crest cells. It tends to local recurrences and dissemination and the prognosis has to be considered as poor. Based on a small series of patients, a wide surgical excision of the primary tumour or amputation are the therapies of choice. Radiotherapy might be of some value as an adjuvant treatment but radiotherapy and chemotherapy are of little value in the treatment of the advanced disease. Because of the lack of treatment alternatives we treated a 40-year-old female patient with disseminated clear cell sarcoma with interferon-alpha 2b (IFN-alpha 2b) perilesionally after several courses of systemic chemotherapy and radiotherapy had failed. After 4 months of therapy the patient came into a complete pathological remission which lasted for 17 months. A relapse of round cell sarcoma on both tumour sites was then noted. This outcome shows that IFN-alpha 2b was able to induce a complete remission in clear cell sarcoma and might have altered the natural course of the disease. IFN-alpha should be studied as adjuvant therapy after surgery of primary clear cell sarcoma and as a first-line palliative treatment in disseminated disease.

Adult↗
PubMed1989

Mucin-like cancer-associated antigen (MCA) compared with CA 15-3 in advanced breast cancer.

Mucin-like cancer-associated antigen (MCA), a new tumor marker using the mouse monoclonal antibody b-12 is thought to be of value in the management of patients with breast cancer. In this study sera from 191 female patients with breast cancer (112 with progressive disease [PD] and 79 with no evidence of disease [NED]) were analyzed for MCA levels and compared with those of cancer antigen 15-3 (CA 15-3) in single determination and in combination with carcinoembryonic antigen (CEA) and tissue polypeptide antigen (TPA). A cut-off level of 14 U/ml for MCA seems to be more appropriate than the recommended 11 U/ml to distinguish between PD and NED in patients with breast cancer. Although there was a fairly good correlation of MCA to CA 15-3, MCA was inferior in sensitivity and specificity to CA 15-3. Patients with osseous metastases and those with more than one metastatic site showed higher MCA levels than patients with visceral or soft tissue metastases, a fact which was comparable to CA 15-3. Combining MCA and CA 15-3 resulted in a gain in specificity but marked loss of sensitivity. The combination of MCA and CEA results also in a loss of sensitivity whereas the combination of CA 15-3 and CEA showed an increased specificity and only a negligible loss of sensitivity. The combination of MCA with TPA is of little value in the follow-up of breast cancer, as is the combination of CA 15-3 with TPA. The combination of CA 15-3 with CEA can be still recommended for follow-up for early detection of metastases in breast cancer.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Long-term remission in a patient with erythroleukemia following interferon-alpha treatment.

A patient in second relapse of acute erythroleukemia (AEL) was treated with 10 MU of recombinant interferon (IFN)-alpha subcutaneously for 24 days after he had failed standard chemotherapy. Besides fever up to 38.9 degrees C and a transient raise in liver function parameters, treatment was well tolerated but had to be discontinued because of a severe decrease in white blood cell and platelet count. After termination of IFN treatment, both cell populations showed a continuous rise during the following weeks and hemoglobin increased concomitantly. Partial remission could be reached as was demonstrated by a decrease in PAS-positive erythroblasts in bone marrow biopsy. Further studies with IFN in patients with AEL refractory to cytostatic chemotherapy are recommended.

Adult↗