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B Opalka

Publications and source records attributed to B Opalka.

At least 55 records · Page 3Linked to original sources
PubMed1994

Altered host range phenotype of the transformation-defective Ad12 mutant CS-1 is due to deletions in the E1 region.

Although it grows well in bulk infection, human adenovirus type 12 (Ad12) does not plaque efficiently in Vero cells of simian origin. After long-term passage of the virus or after transfection of Ad12 DNA into these cells, however, transformation-defective, host-range mutants giving high plaque yields in Vero cells were isolated. The original mutants have deletions in both E1a and E1b as well as additions of viral sequences at the right terminus of the genome. We have constructed a recombinant virus (Ad12d169) carrying both E1 alterations of the original mutant CS-1 on the Ad12 wild-type background. Another mutant (Ad12mut2) has additional sequences at the right terminus and an intact E1 region. In plaque assays mutant virus Ad12d169 carrying E1a deletions has an about thousandfold higher efficiency in Vero cells than Ad12wt and Ad12mut2, mapping the enhanced replication in Vero cells to the deletions in E1. Mechanical models for the influence of the E1 deletions, for example by up-regulation of the E2-encoded DNA-binding protein, are discussed to explain the efficient replication of mutant adenoviruses in Vero cells under plaque assay conditions.

Adenovirus E1 Proteins↗
PubMed1994

Presence of re-appearance of BCR-ABL-positive cells years after allogeneic bone marrow transplantation for chronic-phase chronic myelogenous leukemia in patients in hematological remission.

Allogeneic bone marrow transplantation (BMT) is considered to be the only curative therapy for chronic myelogenous leukemia (CML). The cytogenetic marker of CML, the Philadelphia (Ph) chromosome, or the molecular alterations caused by the BCR-ABL gene fusion can be used to monitor the success of treatment. A sensitive two-step reverse-transcription polymerase chain reaction (RT-PCR) was done to score BCR-ABL-mRNA-positive leukemic cells in frozen bone marrow samples of 15 CML patients retrospectively. These patients, 4 females, 11 males, had undergone BMT during the first chronic phase after a preparative regimen consisting of total body irradiation (TBI) and cyclophosphamide; median age at BMT was 38 years (range 20-49 years). At the time of this study, 8 patients were in cytogenetic and/or clinical remission. Seven patients relapsed after BMT; all presented with Ph-chromosome-positive metaphases and BCR-ABL-positive cells at the time of relapse. In only 1 patient in hematologic remission was no positive PCR analysis obtained in the two samples tested. However, 5 patients have remained or became Ph-chromosome and/or PCR-positive after BMT without clinical symptoms of disease. In samples from another patient, transient presence of leukemic cells was observed only early after BMT. Clinically, these patients were relapse free at days 3,055, 2,581, 2,252, 1,846, 1,839, 1,747, and 1,173 after BMT, respectively. Based on these data, the presence of single BCR-ABL-positive cells > 1 year after BMT has no prognostic significance.

Adult↗
PubMed1994

Bcr-abl-positive and -negative clonogenic cells in CML patients undergoing long-term interferon treatment.

Bone marrow (BM) and peripheral blood cell (PBC) samples of 11 Philadelphia (Ph) chromosome-positive chronic myelogenous leukemia (CML) patients in long-lasting hematologic remission induced by interferon (IFN) treatment were examined for the presence of leukemic hematopoietic precursor cells. Southern blot analysis revealed residual leukemic cells in BM samples of four patients, whereas seven patients showed no aberrant bands. Reverse transcription polymerase chain reaction (RT-PCR), however, amplified bcr-abl-specific cDNA in unfractionated BM or PBC samples in all 11 patients. The patients demonstrating bcr rearrangements in Southern blots had either a mosaic pattern (three patients) of bcr-abl-negative and positive colony-forming precursors (CFU-GEMM, BFU-E, CFU-GM, CFU-Mega), or all colonies were derived from leukemic precursors (one patient). However, in soft agar cultures of four patients without aberrant bands in Southern blots, only colonies without amplifiable bcr-abl transcripts were detectable. In another patient, few bcr-abl-positive colonies were found after 44 months of treatment, but not after 53 and 56 months of therapy. In these patients, therefore, residual disease detectable by PCR analysis of unfractionated cell samples does not appear to reside in the colony-forming cell compartment. The prognostic implications of these observations and the nature of the remaining bcr-abl-positive cells within unfractionated cell samples remain to be determined.

Adult↗
PubMed1993

Age distribution of latent herpes simplex virus 1 and varicella-zoster virus genome in human nervous tissue.

Latency in nervous tissue caused by herpes simplex virus 1 (HSV-1) and by varicella-zoster virus (VZV) is an intriguing feature of herpes-virus' neurotropism. HSV-1 and VZV latency are the causes of ophthalmic zoster and recurrent HSV infections in the distributions of the trigeminal branches. HSV-1 neuronal latency may play a role in the etiopathogenesis of HSV encephalitis. We attempted to determine the prevalence and age distribution of VZV and HSV latency. We applied nested polymerase chain reaction (PCR) assays to detect HSV-1 and VZV genome in trigeminal ganglia and olfactory bulbs which were obtained from 109 human corpses at forensic postmortems. HSV-1 latency was found in 72.5% of trigeminal ganglia and in 15.5% of olfactory bulbs. VZV latency was 63.3% in trigeminal ganglia and 1% in olfactory bulbs. Simultaneous latency of VZV and HSV genome occurs in 48.8% of trigeminal ganglia. The age-group specific prevalence of HSV neuronal latency increases from 18.2% in 0-20 years to reach finally 100% in persons older than 60 years. Age specific prevalences of VZV peaked for a first time with 82% between 21-30 years, fell to 50% for 40-50 years, and rose to 89% for 71-80 years. If the latent trigeminal ganglion HSV-1 genome were the source of endogenously acquired encephalitis, the peak incidence of HSV encephalitis in older subjects correlates with our findings. Increased VZV latency prevalence in nervous tissue of younger people without subsequent disease indicates sufficient immune surveillance.

Adult↗
PubMed1993

Analysis of the p53 gene in patients with isochromosome 17q and Ph1-positive or -negative myeloid leukemia.

Increased incidence of p53 gene aberrations or chromosome 17p monosomy resulting from an isochromosome 17q [i(17q)] has been observed with transition of chronic myelogenous leukemia (CML) to myeloid blast crisis (BC), and in some patients with poor risk acute myeloid leukemia (AML) progressing from myelodysplastic syndrome (MDS). These data suggested that disease progression may be linked to bi-allelic inactivation of p53. Here, we report on p53 gene analyses of nine patients with CML-BC and AML who showed an i(17q) as characteristic cytogenetic anomaly. Using Southern blots, agarose gel electrophoresis and single-strand conformation polymorphism analyses of PCR products from genomic DNA and cDNA, spanning exons 4 through 9, we did not detect any structural abnormalities of the remaining p53 allele. These findings question the hypothesis that p53 gene alterations are the principal molecular event responsible for progression of CML chronic phase or MDS to i(17q)-positive CML-BC or AML, respectively.

Adult↗
PubMed1993

Impact of interferon alpha-induced cytogenetic improvement on survival in chronic myelogenous leukaemia.

The objective of this study was to investigate the prognostic impact of the reduction of Philadelphia chromosome (Ph) positive metaphases by treatment of chronic myelogenous leukaemia (CML) with interferon (IFN) alpha. Therefore, we evaluated the outcome of patients with previously untreated chronic phase Ph-positive CML, enrolled from 1984 to 1990 into two consecutive IFN trials at our institution. Of a total of 71 patients, 62 (87%) were evaluable for cytogenetic response. No cytogenetic improvement was seen in 16 patients (23%), 28 patients (38%) had a decrease in Ph-positive bone marrow metaphases to levels ranging from 35% to 95%, and nine patients (13%) to levels between 5% and 34%. In nine patients (13%), Ph-positive metaphases were no longer detectable. After a median follow-up period of 33 months, the projected 5-year survival is 55% for the 62 patients evaluable for cytogenetic response. In this patient population there was no significant difference in the survival probability according to patients' risk status as defined by the Sokal score. Categorization according to the extent of Ph reduction, however, allowed three groups with significantly different prognoses to be identified. Patients achieving a Ph reduction to less than 35% were found to constitute a low risk group with a median survival not yet known and a projected 5-year survival of 90%. The 5-year survival rate was 55% for patients with a Ph reduction to levels between 35% and 95%, and less than 10% for those without any cytogenetic improvement. Thus, this study demonstrates that cytogenetic improvement on IFN treatment is an important prognostic factor for survival.

Adolescent↗
PubMed1993

Long-term treatment of chronic myelogenous leukemia with different interferons: results from three studies.

131 patients with Philadelphia (Ph') chromosome positive chronic myelogenous leukemia (CML) were treated with interferon (IFN) alpha or a combination of IFN alpha and IFN gamma. In study, 1, 13 not pretreated and 41 pretreated patients, 48 in chronic phase disease, 6 in accelerated phase, received 4 x 10(6) U/m2 IFN alfa-2b initially. After achievement of hematologic remission, the individually minimum effective dose was used for maintenance. There was no response in acute phase disease. Of the 48 patients with chronic phase disease, 22 achieved a hematologic remission (HR), 13 a partial HR (PHR), and 13 did not respond (NR) to IFN. No major cytogenetic response occurred in these patients, but two patients achieved a major molecular response in Southern blots, whereas PCR tests were positive. In a further randomized study, CML patients without prior therapy were treated initially with 4 x 10(6) U/m2 IFN alpha alone (arm A) or in combination with 50 micrograms IFN gamma (arm B). For maintenance, the maximum tolerable dose of IFN alpha was given (up to 10 x 10(6) U/day). Thirteen patients in arm A (54%) and 14 (56%) patients in arm B achieved a HR, 7 patients (29%) in arm A and 6 patients (24%) in arm B a PHR. No response could be induced in 4 patients (17%) of arm A and 5 patients (21%) of arm B. Major cytogenetic responses were observed in 5 (20%) patients of arm A and 5 patients (20%) of arm B. Major molecular responses were observed in 3 patients of arm A and 5 patients of arm B.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Tumor necrosis factor alpha modifies resistance to interferon alpha in vivo: first clinical data.

Patients with Philadelphia-positive chronic-phase chronic myelogenous leukemia (CML) resistant to interferon (IFN) alpha were treated in a phase I/II study with recombinant human tumor necrosis factor alpha to overcome IFN alpha resistance. Doses of 40, 80, 120 or 160 micrograms/m2 TNF alpha were given as 2-h infusions on 5 consecutive days every 3 weeks. IFN alpha (4 x 10(6) IU/m2 s.c., daily) treatment was continued. Six patients were treated, completing 1-24 (median, 12) treatment cycles. Five of the six patients achieved partial hematological remission, while the remaining patient had to stop treatment because of WHO grade 4 thrombocytopenia following the first TNF alpha cycle. No complete hematologic remission or cytogenetic improvement was seen. Side-effects were similar to those described for both substances alone. Maximum tolerable TNF doses usually varied between 80 micrograms/m2 and 160 micrograms/m2. To examine possible pathways of TNF activity in these patients, interferon receptor status and (2'-5')-oligoadenylate synthetase levels were examined in peripheral blood mononuclear cells. Both parameters remained unchanged during TNF alpha treatment. These preliminary data point to significant clinical efficacy of additionally applied TNF alpha in IFN alpha-resistant CML patients.

2',5'-Oligoadenylate Synthetase↗
PubMed1992

No correlation between site of breakpoint in the BCR gene and platelet counts in Philadelphia chromosome-positive CML.

In chronic myelogenous leukemia (CML) malignant cells are characterised by the Philadelphia chromosome (Ph), resulting from a translocation t(9;22). The position of the breakpoint within the major breakpoint cluster region (M-bcr) on chromosome 22 has been shown to correlate with the clinical course of the disease or, more recently, thrombopoietic activity. We have therefore determined the breakpoint localisation in 53 Ph-positive CML patients. Following the 5'/3'-region definition of Inokuchi et al. Leukemia Research 15, 1067 (1991) [1], 22 of our patients have 5' and 31 of our patients have 3' orientated breaks. No correlation was found between platelet counts and breakpoint localisation.

Chromosome Aberrations↗
PubMed1992

Combination therapy with interferon alpha-2b plus low-dose interferon gamma in pretreated patients with Ph-positive chronic myelogenous leukaemia.

Between March 1988 and July 1990, 28 adults with chronic myelogenous leukaemia (CML) were treated with a combination of recombinant human interferon (IFN) alpha-2b s.c. (initial dose 4 x 10(6) U/m2) and recombinant human IFN gamma s.c. (50 micrograms totally) daily. All patients were in chronic phase disease and had been treated previously with chemotherapy or bone marrow transplantation. A complete haematologic remission was achieved in three patients (11%), a haematologic remission in 12 patients (43%), and a partial haematologic remission in seven patients (25%). Six patients did not respond to this schedule. Acute side-effects were flu-like symptoms, fever and chills. During long-term treatment six patients developed polyarthralgia. Haematotoxicity WHO grade III occurred in three patients, and WHO grade IV in two patients. One patient developed psychosis, and in another patient an exacerbation of a pre-existing sarcoidosis was observed. We conclude that this combination is tolerable and effective in inducing haematological remissions in pretreated CML patients.

Adolescent↗
PubMed1992

A prospective randomized comparison of single-agent interferon (IFN)-alpha with the combination of IFN-alpha and low-dose IFN-gamma in chronic myelogenous leukaemia.

In patients with previously untreated chronic myelogenous leukaemia (CML) the efficacy of single-agent interferon (IFN)-alpha at an initial dose of 4 x 10(6) U/m2 (arm A) was compared with the combined administration of the identical dose IFN-alpha plus a total dose of 50 micrograms IFN-gamma (arm B). 51 patients entered this study between April 1987 and October 1989; the analysis was performed in March 1991 and was focused on response rates and toxicity. 54% of patients on arm A and 56% of arm B patients attained haematologic remission. 29% of patients on arm A and 24% of arm B patients had partial haematologic remission. A decrease in Philadelphia chromosome (Ph)-positive metaphases of more than 10% was only seen in patients who had achieved complete haematologic normalization. In 21% of patients on arm A and 20% of arm B patients, the percentage of Ph-positive cells declined to less than 35%. Toxicity was different between the two study groups with more pronounced hepatotoxicity observed in patients treated with IFN-alpha alone. Among the patients receiving both IFNs, alpha and gamma, there were 2 fatal infectious complications. This serious toxicity in conjunction with lack of a clinically meaningful difference between the two treatment schedules has led us to terminate the study. In conclusion, the addition of low-dose IFN-gamma failed to improve the efficacy of IFN-alpha in this study.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1992

The transformation-defective adenovirus 12 host range mutant CS-1 lacks the E1a-specific 9.5S mRNA and contains a second deletion in E1b.

We have further analyzed structure and expression of the E1 region of the transformation-defective adenovirus 12 (Ad12) host range mutant CS-1. Using cDNA polymerase chain reaction analysis, the E1a region was found to give raise to five transcripts analogous to the Ad12wt 13S, 12S, 11S, 10S species and the normal 9S mRNA. Due to loss of a splice acceptor site at position 852, the Ad12wt-specific 9.5S transcript cannot be synthesized by the mutant CS-1. The fact that the virus is, however, completely viable indicates that this mRNA is dispensable for lytic growth of Ad12. Besides the deletions in E1a described previously, a second deletion of 31 base pairs was found in the E1b gene. It affects the start site of the E1b-specific mRNAs and destroys or eliminates the AUG sequence for the E1b 19-kD protein. As shown earlier, normal E1b mRNA expression is found in mutant-infected cells, but no 19-kD E1b protein was immunoprecipitated by an E1-specific rat tumor serum.

Adenovirus Early Proteins↗
PubMed1992

Treatment of chronic myelogenous leukemia with different cytokines.

In vitro data suggest a synergistic antiproliferative effect of different cytokines. In four clinical studies chronic myelogenous leukemia (CML) patients were treated with interferon (IFN)-alpha alone or IFN-alpha combined with either low-dose IFN-gamma or tumor necrosis factor (TNF)-alpha. The best response was achieved in previously untreated patients with good prognostic factors and highest tolerable IFN dose for maintenance treatment. Breakpoint localization within the major breakpoint cluster region did not correlate with response to IFN. In a randomized study of IFN-alpha versus IFN-alpha combined with IFN-gamma, no differences in response rates were observed. Patients with primary or secondary resistance to these treatment modalities received a combination therapy with IFN-alpha and TNF-alpha. In these patients, a decrease in leukocyte counts was noted, but no cytogenetic improvement occurred.

Adult↗
PubMed1991

Minimal residual disease in patients with chronic myelogenous leukemia undergoing long-term treatment with recombinant interferon alpha-2b alone or in combination with interferon gamma.

Interferon (IFN) therapy has become widely used for the treatment of chronic myelogenous leukemia. Hematologic remissions can be induced in about 60% of patients. Moreover, in a small number of patients loss of the Philadelphia (Ph) chromosome and of the BCR-ABL rearrangement is observed. We have used genomic Southern blotting as well as a two-step polymerase chain reaction (PCR) method to score for BCR-ABL messenger RNA (mRNA) in patients with hematologic remission induced by treatment with IFN alpha-2b alone or in combination with IFN gamma. Concomitantly, cytogenetic analysis was performed. In 11 of 115 patients reported here, a complete loss of rearranged BCR fragments was observed in Southern blots of peripheral blood (PB) and/or bone marrow (BM) cell samples. Malignant marker bands disappeared first in the PB. In six patients, this genotype remained stable, whereas in five patients, low-intensity, rearranged bands reappeared despite continuation of treatment. The reappearance of the malignant marker was not accompanied by a clinical relapse. Ph-negative metaphases were observed in PB cells of four patients and in the PB and BM cells of two of these patients. In the samples of the other patients, residual Ph-positive cells were detected. By two-step PCR, residual BCR-ABL rearranged transcripts were found in samples of 10 patients.

Adult↗
PubMed1991

Interferon alfa-2b in acute- and chronic-phase chronic myelogenous leukaemia: initial response and long-term results in 54 patients.

Fifty-four patients with Ph1-positive chronic myelogenous leukaemia (CML) (48 with chronic-phase and six acute-phase disease) were treated with interferon alfa-2b subcutaneously (s.c.). The starting dose was 4 million units (MU)/m2 body surface area daily. It was reduced in parallel with serially determined leucocyte counts, and minimal effective doses were given as maintenance after achieving remission. Haematological remissions were induced in 22 of the 48 patients (46%) with chronic-phase disease. Thirteen patients (27%) revealed partial haematological remission and another 13 no response to treatment. No complete remission could be induced, although minor or partial cytogenetic responses were seen in 16 patients (33%). Moreover, a bcr-abl reduction was detected on Southern blot analysis in two patients. In chronic-phase disease, results of treatment were influenced by elapsed time after diagnosis, extent of previous treatment and interferon dosage. No beneficial effects of interferon were detected in the six patients with acute-phase disease. Principal acute side effects were fever and flu-like symptoms at the beginning of the therapy, which usually subsided within 3-7 days. Chronic side effects, especially weakness and neuropathy, were less frequent but more severe and necessitated discontinuation of treatment in 10 patients. In summary, interferon alfa-2b seems to be an effective treatment in early chronic-phase CML. Long-term effects on the course of the disease, however, must be determined.

Adolescent↗