PubMed Health⌕ Search

Biomedical subjects

G Steger

Publications and source records attributed to G Steger.

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

MACOP-B treatment in patients with Ki-1-positive large-cell anaplastic lymphoma.

Nine adult patients with Ki-1-positive large-cell anaplastic lymphoma were treated with MACOP-B. Two suffered from relapsed disease and had previously received chemotherapy; a third patient had received a single dose of 100 mg/m2 cisplatin before initiation of MACOP-B. The stage of lymphoma was determined according to the Ann Arbor Conference criteria and was II in one, III in two and IV in six patients. All patients had constitutional symptoms. Five patients had achieved complete remission 4 weeks after termination of the protocol and there were two partial remissions. One patient died of massive pulmonary embolism during the 4th week of treatment; another patient, who had received MACOP-B as salvage therapy, died of progressive lymphoma 1 month after completion of the regimen. Maximal observed toxicities according to WHO were mucositis grade 3 (n = 3) and there were three cases with thromboembolic complications, including a fatal pulmonary embolism in a young patient. However, MACOP-B appears an effective, fairly well-tolerated and feasible therapy for patients with Ki-1-positive large-cell anaplastic lymphoma.

Adult↗
PubMed1992

In vitro expressed HPV 8 E6 protein does not bind p53.

The oncogene E6 of human papillomavirus 8, which is associated with skin cancers in epidermodysplasia verruciformis, was transcribed and translated in vitro. The resulting 17 kDa protein did not bind to the cellular p53 in contrast to E6 of HPV16.

Cloning, Molecular↗
PubMed1992

Simultaneous occurrence of t(14;18) and t(8;22) common acute lymphoblastic leukemia.

A young male patient progressed rapidly from localized abdominal lymph node enlargement to overt acute lymphoblastic leukemia. Despite aggressive treatment, he died of progressive CNS leukemia 5 months after initial presentation. At diagnosis, karyotypic analysis of an abdominal lymph node revealed the coexistence of t(14;18) (q32;q21), specific for follicular lymphoma, and t(8;22) (q24;q11), a variant Burkitt translocation. Such cases might be considered as a model for a general mechanism of tumor progression with cascade-like involvement of oncogenes.

Adult↗
PubMed1992

Short-term energy balance in patients with infections: carbohydrate-based versus fat-based diets.

The effects of a carbohydrate-based diet (50% carbohydrate calories, 30% fat calories, 20% protein calories) versus a fat-based diet (28% carbohydrate calories, 55% fat calories, 17% protein calories) on oxidation rates of carbohydrate, fat, and protein were assessed in 12 patients with infections by indirect calorimetry and estimation of urea nitrogen production rate. The diets were given continuously for 18 hours in a randomized cross-over study on 2 consecutive days. Energy supply (kcal/d) was adjusted individually to meet the energy expenditure measured on the preceding day after an overnight fast and was 1,647 +/- 129 (SEM) for the carbohydrate-based diet and 1,655 +/- 131 for the fat-based diet. Oxidation rates (kcal/d) for carbohydrate (carbohydrate-based diet, 525 +/- 70; fat-based diet, 363 +/- 84) were different between the diets (P less than .05), whereas no difference could be found for fat (carbohydrate-based diet, 820 +/- 117; fat-based diet, 968 +/- 136) and protein (carbohydrate-based diet, 252 +/- 29; fat-based diet, 236 +/- 23). However, during carbohydrate-based feeding, carbohydrate balance (288 +/- 93 kcal/d) and fat balance (-327 +/- 107 kcal/d) were significantly different from zero (P less than .05), indicating continuous oxidation of endogenous fat and storage of administered glucose. During the fat-based diet, carbohydrate and fat balances were not different from zero. A correlation between energy and substrate balances was not seen during either diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

DNA ploidy and other results of DNA flow cytometry as prognostic factors in operable breast cancer: 10 year results of a randomised study.

We evaluated breast cancer specimens from 241 patients of a controlled clinical trial by means of DNA flow cytometry. We report the correlations between DNA index (DNI) and fraction of cells in S-phase (SPF) and other prognostic parameters. Both univariately and in a Cox model, the predictive power of these factors is evaluated after a follow-up of more than 10 years. There are strong correlations between DNI and SPF (P = 0.0001) and between flow cytometry parameters and clinical and histopathological factors such as axillary lymph node involvement, tumour size and histological grade. In univariate analysis DNI fails to provide prognostic information, whereas SPF turns out to be able to differentiate between patients at high and low risk for relapse and death (P = 0.002). In the multivariate Cox model, too, SPF is an important prognostic parameter with respect to patient survival (relative risk: +86%), only surpassed by nodal involvement. DNI, however, turns out to be an independent predictor of relapse free survival and distant recurrence free survival. By combination of DNI and SPF, patients can be divided into three prognostic subgroups. We conclude that data from DNA flow cytometry can be of great importance for the decision on the level of aggressiveness of adjuvant therapy for an individual patient and therefore may help to avoid overtreatment and toxicity.

Adult↗
PubMed1992

Base-pair probability profiles of RNA secondary structures.

Dynamic programming algorithms are able to predict optimal and suboptimal secondary structures of RNA. These suboptimal or alternative secondary structures are important for the biological function of RNA. The distribution of secondary structures present in solution is governed by the thermodynamic equilibrium between the different structures. An algorithm is presented which approximates the total partition function by a Boltzmann-weighted summation of optimal and suboptimal secondary structures at several temperatures. A clear representation of the equilibrium distribution of secondary structures is derived from a two-dimensional bonding matrix with base-pairing probability as the third dimension. The temperature dependence of the equilibrium distribution gives the denaturation behavior of the nucleic acid, which may be compared to experimental optical denaturation curves after correction for the hypochromicities of the different base-pairs. Similarly, temperature-induced mobility changes detected in temperature-gradient gel electrophoresis of nucleic acids may be interpreted on the basis of the temperature dependence of the equilibrium distribution. Results are illustrated for natural circular and synthetic linear potato spindle tuber viroid RNA respectively, and are compared to experimental data.

Algorithms↗
PubMed1991

Formation of a thermodynamically metastable structure containing hairpin II is critical for infectivity of potato spindle tuber viroid RNA.

The functional relevance of a hairpin II-containing structure of viroid RNA was studied by site-directed mutagenesis, thermodynamic calculations, experimental denaturation curves and infectivity tests. Hairpin II is formed during thermal denaturation of circular viroids or as part of a metastable structure during synthesis of viroid replication intermediates. In potato spindle tuber viroid (PSTVd), eight single-site mutations were generated in the segments which form hairpin II. From the mutated viroid cDNA clones, linear RNA transcripts of PSTVd unit length were synthesized. The relevance of hairpin II for the mechanism of denaturation was confirmed quantitatively by optical denaturation curves and temperature-gradient gel electrophoresis. Infectivity tests showed that the mutations in the core region of hairpin II reverted to the wild type sequence whereas the mutations in the peripheral regions of hairpin II remained genetically stable. These data are in accordance with the natural variance of hairpin II in other viroids of the PSTVd class. Thus, the integrity of the core of hairpin II is critical for infectivity. Hairpin II exhibits a strong similarity in sequence as well as in three-dimensional structure to certain DNA GC-clusters found in the 5'-upstream regions of some genes in man, animals, viruses and plants. A hypothesis about a function of hairpin II as a binding site for host cell transcription factors is proposed.

Base Composition↗
PubMed1991

Effects of random mutagenesis upon potato spindle tuber viroid replication and symptom expression.

A combination of random chemical mutagenesis plus temperature gradient gel electrophoresis was used to isolate a collection of 57 potato spindle tuber viroid (PSTV) cDNAs containing mutations distributed throughout the entire 359 nucleotide genome. Although the presence of multiple mutations was often associated with a loss of cDNA infectivity, infectious PSTV cDNAs containing as many as four unlinked alterations could be isolated. Several mutations in the pathogenicity domain and left terminal loop were stably maintained in the resulting progeny, but those which affect base pairing in secondary hairpins I and II were either lethal or rapidly reverted to wild-type. One stable C----U substitution which may promote significant structural rearrangement within the right side of the pathogenicity domain had no detectable effect upon symptom expression. The variable domains of several noninfectious mutants contained an A----G substitution which is likely to inhibit the in vitro formation of secondary hairpin II via stabilization of the native structure, and the lethal nature of this mutation was confirmed by oligonucleotide-directed mutagenesis. Several lines of evidence now point toward an essential role for secondary hairpin II in the replication of PSTV and related viroids.

Base Sequence↗
PubMed1991

Decreased postheparin lipolytic activity in renal transplant recipients with cyclosporin A.

The patterns of hyperlipidemia in renal transplant recipients (RTRs) are more variable than in the uremic state, showing increases in both very low-density lipoprotein (VLDL) and low density lipoprotein (LDL). This has been attributed, at least in part, to immunosuppressive therapy, especially to treatment with corticosteroids. Postheparin lipolytic activity (PHLA) was determined in 28 RTRs. Sixteen patients presenting with hyperlipidemia comprised group A, who were aged 49.8 +/- 13.5 years, and had a cholesterol of 8.24 +/- 1.86 mmol/liter, triglycerides of 6.02 +/- 3.33 mmol/liter. Twelve patients presenting cholesterol and triglyceride values within the normal range were in group B, and were aged 48.6 +/- 13.3 years. All RTRs received cyclosporin A (CsA) twice daily orally, which were divided in two equal doses and adjusted to provide CsA blood trough levels (RIA) in a range of 250 to 350 ng/ml. Twenty-one RTRs were additionally treated by alternate-day corticosteroids, whereas seven patients had CsA on their sole immunosuppressive agent. PHLA (mumol free fatty acids/ml/hr, given 10 and 20 min after 100 U/heparin kg body wt intravenously) was commonly reduced in RTRs (group A at 10/20 min: 5.6 +/- 1.1/5.26 +/- 1.2; group B: 8.26 +/- 2.91/8.38 +/- 3.44) as compared to the values obtained in healthy controls (15.3 +/- 2.9/17.2 +/- 5.0). This was mainly due to a reduction of the activity of the hepatic triglyceride lipase, and to a minor extent to a reduced activity of peripheral lipoprotein lipase. There was no statistically significant difference of PHLA in RTRs with or without corticosteroid treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Cortex Hormones↗
PubMed1991

Increased incidence of euthyroid and hyperthyroid goiters independently of thyrotropin in patients with acromegaly.

The incidence of palpable goiters, the thyroid functional state and thyroid radioisotope uptake was analyzed retrospectively in 80 patients with acromegaly and 80 patients with prolactinomas. 71% of all patients with acromegaly had an enlargement of the thyroid (goiter); 49% of them had diffuse and 39% nodular goiters. The incidence of goiters in patients with prolactinomas from the same iodine deficient geographic region was only 35% (82% diffuse and 18% nodular). 17.5% of acromegalic patients underwent thyroid surgery before diagnosis of growth hormone excess. 17.5% of acromegalic patients with goiters had autonomous areas in their thyroids and 5% were clearly hyperthyroid. Goiters developed slightly more often in females (74%) than in males (67%). The mean preoperative growth hormone level was higher in acromegalic patients with goiter. The incidence of goiters was positively correlated with the documented time of elevated growth hormone concentration in serum. Two patients with exaggerated response of thyrotropin (TSH) (delta TSH greater than 20 mU/l) to the application of thyrotropin-releasing hormone (TRH) had no goiters. On the other hand most patients (61%) with goiters had a low TSH-response to TRH (delta TSH less than 10 mU/l) representing in part occult autonomy of thyroid function. No patient with prolactinoma has had previous thyroid surgery nor thyroid autonomy. One patient with prolactinoma suffered from Graves' disease and none of the acromegalic patients had this disease. We finally conclude that the elevation of growth hormone leads to increased incidence of euthyroid and hyperthyroid (autonomous) goiters independently of the influence of TSH.

Acromegaly↗
PubMed1991

[Current status of adjuvant therapy in patients with colorectal cancer: report and commentary on the Consensus Conference, 16-18 April 1990, National Cancer Institute, Bethesda, Maryland].

This is a report on the Consensus Development Conference on adjuvant therapy for patients with colorectal carcinoma, which was held at the National Cancer Institute of the National Institutes of Health (NIH) in Bethesda, Maryland between April 16th and 18th 1990. Based on statistically significant results of a clinical trial adjuvant therapy with 5-fluorouracil (5-FU) and levamisole was recommended outside controlled clinical studies for patients with Dukes C colon carcinoma, but because no optimal form of adjuvant therapy yet exists there is still the need for further trials. No recommendations were given for patients with Dukes B colon carcinoma. For patients with Dukes B + C rectal cancer combined radiation therapy and 5-FU-based chemotherapy was considered "standard therapy" according to the consensus panel, but this recommendation seems to be still worth discussing. Since there is need of further evaluation of newly-recognized prognostic factors and also to optimize adjuvant strategies the panel stated that further prospective randomized studies are warranted. Hence, the establishment of a multicentre study group also in Austria appears to be an essential application of such trials in order to contribute towards ameliorating the prognosis of patients with colorectal carcinoma.

Colorectal Neoplasms↗
PubMed1990

[Anti-CEA immunoscintigraphy in postoperative follow-up of tumor patients. Differentiated use of various monoclonal antibody preparations].

The sensitivity of immunoscintigraphy (ISC) with monoclonal antibodies (Mab) depends on the Mab type, the radiophysical properties of the isotope, the labeling method and the tumor localization. We investigated 38 studies with three different Anti-CEA Mab (In111/I131 BW 431, n = 12; I131 IMACIS-1, n = 11; Tc99m BW 431/26, n = 15) in 35 postoperative tumor patients (31 colorectal, 1 gastric, 2 breast and 1 pancreas cancer) with a total of 62 tumor manifestations. Planar ISC was used in all studies. A dual isotope technique with Tc99m-colloid was applied for imaging of liver metastases in the In111/I131 BW 431/31 and I131 IMACIS-1 studies. Whereas the global sensitivity, ranging from 64-73%, was comparable, the different physiological properties of the Mab preparations caused marked differences in the imaging capabilities of certain tumor localizations, especially in the liver. All Mab underestimated the extent of liver involvement, however, the highest regional sensitivity (75%) was found with the I131 IMACIS-1. In contrast, Mab with the highest physiological liver uptake (In111 BW 431/31, Tc99m BW 431/26) imaged liver metastases in most cases unspecifically as cold spot, yielding a sensitivity of 0-9%. No differences between the Mab were seen in the regional sensitivity with respect to lung metastases, which ranged between 33-40%. All tested Mab showed a high sensitivity in imaging local recurrences ranging between 50% for the I131 IMACIS-1 and 100% for the Tc99m BW 431/26. We conclude, that in postoperative tumor patients anti-CEA ISC with Tc99m BW 431/26 is the method of choice for the detection of local recurrences.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Nucleotide sequence and structural analysis of two satellite RNAs associated with chicory yellow mottle virus.

The two satellite RNAs associated with CYMV infections were sequenced. The larger (sCYMV-L1) has only linear molecules 1145 nucleotides long, a poly(A) tail, a long open reading frame (ORF) coding for a protein of Mr 39,636 resembling in composition those of other large nepovirus satellite RNAs, a 5' leader sequence of 16 nucleotides and a 3' non-coding region of 40 nucleotides. In vitro translation of sCYMV-L1 yielded a protein product with a size that corresponded to that predicted from the sequence. The smaller satellite (sCYMV-S1) is 457 nucleotides long, has no ORF of significant length and no in vitro messenger activity. Both linear and circular forms of this satellite RNA were detected in infected tissues. Comparison of the sCYMV-S1 primary structure with the sequences of other small nepoviral satellites reveals large regions of homology. Analysis of the secondary structures derived from the sequences of the plus and minus strands suggests possible consensus sequences for their self-cleavage.

Amino Acid Sequence↗
PubMed1990

Prevalence of antibodies to human papillomavirus type 8 in human sera.

The epidermodysplasia verruciformis-associated human papillomavirus type 8 (HPV-8) poses a high risk for malignant conversion of skin lesions in patients with epidermodysplasia verruciformis. For seroepidemiological studies, the HPV-8 open reading frames for E1, E2, E4, E6, E7, and L1 were bacterially expressed as beta-galactosidase fusion proteins, which were purified by preparative gel electrophoresis. Cleavage with the protease FXa at the engineered recognition site separated the beta-galactosidase polypeptide part from the viral polypeptide. Western blot analysis of 445 serum samples from a randomly selected population with the entire L1 as antigen revealed HPV-8-specific immunoglobulin G antibodies in 20% of the samples. The percentage of positive sera did not significantly differ in different age groups. In some sera, we could also detect immunoglobulin M antibodies. The use of two shortened L1 polypeptides as antigen indicated that there are at least two reactive epitopes in the case of HPV-8 L1. Several sera contained antibodies to the early proteins E1, E2, E4, and E7. E1 and E7 were predominantly detected by sera which were negative for L1. In one case, we found antibodies to E6. Two of four sera of patients with epidermodysplasia verruciformis reacted with HPV-8 L1. The prevalence of anti-HPV-8-L1 antibodies in patients with malignant melanomas was comparable to that in the normal population (27.8%) but was significantly higher in patients with cervical cancer (37.5%), basaliomas (40%), and squamous cell skin carcinomas (72.7%) and in immunocompromised patients with Hodgkin's disease (47.7%).

Antibodies, Viral↗
PubMed1989

Vindesine-epirubicin versus vindesine-mitoxantrone in metastatic breast cancer.

UNLABELLED: The present study was designed to assess the toxicity and efficacy of two chemotherapy protocols in patients with metastatic breast cancer. Starting in December 1985, 230 patients were randomized to receive vindesine (V) (3 mg/m2 i.v.) and mitoxantrone (M) (10 mg/m2 i.v.) or V and epirubicin (E) (40 mg/m2 i.v.) every 3 weeks x 3 and every 4 weeks thereafter. Patients were stratified according to site of disease (visceral, bone or soft tissue dominant) and prior therapy. Patient groups were comparable with respect to menopausal status, age, estrogen receptor status and disease-free interval. About two-thirds of the patients presented with visceral recurrence and 30% with bone lesions: only 8% had soft tissue metastases. RESULTS: We observed a significant difference (p = 0.003) in the frequency of alopecia (WHO grade 3-4, 36% vs. 60% favoring regimen VM); gastrointestinal and hematologic side effects and neurotoxicity were mild and similar for both groups. In 182 evaluable patients there was a 26% response rate (CR + PR. UICC criteria) for VM and 35% for VE (not significant). NC was observed in 37% and 43% of patients treated with VM or VE respectively. There was no significant difference between these two groups with regard to time to progression and survival. The median time of follow-up was 8 months and therefore too short to draw definite conclusions. Both regimens were well tolerated and seem to be equally effective, although the response rate for VM and VE was lower than expected.

Adult↗
PubMed1988

Analysis of RNA structures by temperature-gradient gel electrophoresis: viroid replication and processing.

The structure and structural transitions of single-stranded RNA were investigated by energy calculations and temperature-gradient gel electrophoresis. Most experiments have been carried out on RNA of mature viroids and their replication intermediates, which are RNA (-) strand oligomers and RNA (+) strand oligomers. The technique of temperature-gradient gel electrophoresis proved to be particularly useful for analysing co-existing structures. The secondary structure of lowest free energy for unit length and oligomeric replication intermediates is an extended rod-like structure similar to that of the mature circular viroid. When this structure is used as a model for calculations, there is a large degree of agreement between theoretical and experimental curves. Under particular solution conditions, however, (+) strand oligomers undergo a rearrangement from the extended structure to a branched structure, in which every two units form a region of three helices, together 28 bp long. This structure is called the tri-helical structure. The process of structure formation during the synthesis of oligomers could be followed: at first, a transient multi-branched structure is formed which is then transformed into the extended and the tri-helical structures. The region of the three stable helices serves to divide up the oligomeric (+) strand into structural units which may be recognized by cleavage and ligation enzymes, and be processed into circular mature viroids. Co-transcription of complementary (+) and (-) strands shows that energetically favored double-strand formation may at least partially be prohibited by stable secondary structures of the single strands. Natural replication intermediates have been analysed in respect to their subcellular location and their size distribution. They are associated with the nucleoli as was found earlier for mature viroids. Natural (-) strand oligomers are larger than (+) strand oligomers; both types show a periodicity in the size distribution of two units. The models of the structures, which are involved in viroid processing, are in accordance with recent infectivity data and with the results on natural replication intermediates.

Base Sequence↗
PubMed1988

The clinical course of lung metastases from breast cancer.

The clinical course of 50 breast cancer patients whose first metastases were found in the lungs was investigated. 18 months after the start of primary treatment 50% of the patients had developed pulmonary metastases (range: 0-81 months). In 23% of patients a solitary, and in 68% more than one, lung metastases were detected. After a median time of 4 months, in 56% of patients the disease had spread to further organs with bone (25%) and liver (17%) being the most frequent sites. First line management of lung metastases employed surgery, endocrine treatment, chemotherapy or a combination of these modalities. In 24% of patients a complete response was achieved, and in 11% a partial response, with an overall response rate of 35%. Median survival from detection of lung metastases was 13 months (range 4-123+). Patients with only a solitary lung metastasis survived for a median of 11.5 months as compared to 10.5 months for patients with more than one pulmonary metastases. Patients with a disease-free interval of more than 18 months survived significantly longer than patients with a disease-free survival of 18 months or less.

Adult↗