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J Sällström

Publications and source records attributed to J Sällström.

At least 19 recordsLinked to original sources
PubMed2001

The significance of p53 codon 72 polymorphism for the development of cervical adenocarcinomas.

Infection with the human papillomavirus is an important co-factor in the development of cervical carcinomas. Accordingly, HPV DNA is recognised in most of these tumours. Polymorphism of the p53 gene, codon 72, is also considered a risk factor in the development of cervical carcinoma. However, this finding is contradicted by several observers. In the present investigation, 111 cases of adenocarcinoma of the cervix collected through the Swedish Cancer Registry and 188 controls (females with normal cytology at organised gynaecological screening) were analysed with regard to p53, codon 72, polymorphism using a PCR- and SSCP-based technique. In the controls, 9% showed pro/pro, 44% pro/arg and 47% arg/arg, whereas in the invasive adenocarcinomas, the corresponding figures were 0%, 29% and 71%, respectively. The difference was statistically significant (P = 0.001). HPV DNA was identified in 86 tumours (HPV 18 in 48, HPV 16 in 31 and HPV of unknown type in 7 cases) and 25 tumours were HPV negative. The p53, codon 72, genotypes observed in HPV-positive and HPV-negative cervical adenocarcinomas were not statistically different (P = 0.690). The results indicate that women homozygotic for arg/arg in codon 72 of the p53 gene are at an increased risk for the development of cervical adenocarcinomas. However, this genetic disposition seems to be unrelated to the HPV infection.

Adenocarcinoma↗
PubMed2000

Uneven distribution of HPV 16 E6 prototype and variant (L83V) oncoprotein in cervical neoplastic lesions.

A previous Swedish study revealed that both prototype and variant HPV16 E6 oncoprotein, occur in about equal numbers in high-grade cervical intraepithelial neoplasia (HCIN), whereas variant HPV16 predominates in invasive cervical squamous carcinoma. Most of the malignant HPV16 variants contain a common mutation, L83V, in the E6 oncoprotein. In the present investigation, 28 HPV16 positive, invasive cervical adenocarcinomas were collected from a total number of 131 adenocarcinomas. These HPV16-positive cases were evaluated with analysis of the E6 gene, using a recently described PCR-SSCP method for identification of the specific mutation (L83V) in the E6 gene. The results obtained were correlated to findings in 103 preinvasive, HCIN, and 31 invasive cervical squamous carcinomas also infected with HPV16. The HPV16 E6 variant L83V was present in 40% of the HCIN lesions, in 54% of the invasive adenocarcinomas, in comparison to 81% of the invasive squamous carcinomas. The difference between HCIN and squamous carcinomas was statistically significant, P < 0.001, whereas the difference between HCIN and invasive adenocarcinomas was not statistically significant, P = 0.604. Prototype HPV16 and its E6 variant L83V are both prevalent in preinvasive and invasive cervical lesions in Swedish women. However, the obvious predominance of HPV16 variant in squamous carcinomas was not seen in adenocarcinomas. A single amino-acid shift in the HPV16 E6 gene appears to result in a different transforming potential in squamous and glandular cervical lesions.

Adenocarcinoma↗
PubMed2000

Recovering DNA and optimizing PCR conditions from microdissected formalin-fixed and paraffin-embedded materials.

Microdissection is a powerful technique in molecular pathology and genetic investigations. To detect genetic alterations such as gene mutation or deletion from tumor specimen, the purity of target cells is extremely critical. Unwanted cell contamination will dramatically dilute the detectable level of the abnormality. The major obstacle in clinical research is to obtain sufficient and qualified DNA from a small amount of formalin-fixed and paraffin-embedded materials. We have successfully modified our previous protocols and overcome the difficulties of recovery of DNA. After these modifications, almost every single formalin-fixed and paraffin-embedded specimen has been successfully amplified in the required DNA region.

DNA↗
PubMed1999

Molecular and biochemical mechanisms of fludarabine and cladribine resistance in a human promyelocytic cell line.

2F-Adenine arabinoside (fludarabine, Fara-A) and 2-chloro-2'-deoxyadenosine (cladribine, CdA) are nucleoside analogues with antineoplastic activity in vitro and in vivo. Lack of clinical resistance between CdA and Fara-A has been demonstrated in patients with chronic lymphocytic leukemia (G. Juliusson et al., N. Engl. J. Med., 327: 1056-1061, 1992). To clarify the differences in mechanism of resistance to CdA and Fara-A in vitro, we developed two stable, resistant cell lines, HL60/CdA and HL60/ Fara-A, by exposure to increasing concentrations of analogues over a period of 8 months. Resistant cells tolerated >8,000 and 5-fold higher concentrations of CdA and Fara-A, respectively. The specific activity of the nucleoside phosphorylating enzyme (using deoxycytidine as substrate) in cell extracts from HL60/CdA and HL60/Fara-A mutants was about 10 and 60%, respectively, compared with the parental cell line. Western blot analysis using a polyclonal antibody showed no detectable deoxycytidine kinase (dCK) protein in CdA-resistant cells, whereas in Fara-A-resistant cells, it was at the same level as in the parental cells. The mitochondrial enzyme deoxyguanosine kinase was not altered in resistant cell lines. The HL60/CdA cells showed cross-resistance to 2-chloro-2'-arabino-fluoro-2'-deoxyadenosine, Fara-A, arabinofuranosyl cytosine, difluorodeoxyguanosine, and difluorodeoxycytidine toxicity, most likely because of the decreased phosphorylation of these analogues by dCK. Using real-time quantitative PCR, the mRNA levels of dCK and cytosolic 5'-nucleotidase (5'-NT), a major nucleoside dephosphorylating enzyme, were measured. It was shown that the dCK mRNA levels in both CdA- and Fara-A resistant cells were decreased in parallel with the activity. The expression of 5'-NT mRNA was not significantly elevated in CdA- and Fara-A resistant cells, as compared with the parental cells. Ribonucleotide reductase maintains a balanced supply of deoxynucleotide triphosphate pools in the cell and may also be a major cellular target for CdA and Fara-A nucleotides. Except for the deoxycytidine triphosphate level, the intracellular deoxynucleotide triphosphate pools were significantly higher in Fara-A-resistant cells compared with the parental cell line. This might be a consequence of mutation or altered regulation of ribonucleotide reductase activity and may explain the 2-5-fold cross-resistance to several nucleoside analogues observed with HL60/Fara-A cells. It is likely that the resistance for CdA was mainly attributable to a dCK deficiency, and Fara-A-resistant cells might have another contributing factor to the resistance beyond the dCK deficiency.

Antineoplastic Agents↗
PubMed1999

Staphylococcus aureus Cowan strain 1 activation of B-chronic lymphocytic leukaemia cells augments the response to CD40 stimulation.

The signals involved in regulating the proliferation, differentiation and survival of B-chronic lymphocytic leukemia (B-CLL) cells are fully understood. B-CLL cells have been found to respond poorly to various activation signals and only after successful Epstein-Barr virus (EBV) transformation has it been possible to maintain such cells in long-term cultures. In this work we describe a new method to activate and induce proliferation in B-CLL cells and to maintain such cells in long-term culture for longer than 1 month. We used a combination of protocols in an attempt to mimic some of the signals of a thymus-dependent immune response. The B-CLL cells were first activated with Staphylococcus aureus Cowan strain 1 (SAC) particles plus thioredoxin (Trx), followed by stimulation with interleukin (IL)-2 + Trx. This treatment primed the cells for further stimulation with anti-CD40 monoclonal antibody (MoAb) presented on irradiated CD32L cells (the CD40-system) or soluble CD40 Ligand, and a combination of Trx and cytokines (IL-4 + IL-10), which allowed the cells to be maintained for up to 1 month with preserved viability and a variable rate of proliferation. However, induced proliferation of the B-CLL cells was limited to approximately 1 month, suggesting that additional signals are required to facilitate further proliferation.

Burkitt Lymphoma↗
PubMed1999

Rapid test for identification of a human papillomavirus 16 E6 L83V variant.

A variant of human papillomavirus (HPV) 16 has been shown recently to be more prevalent in invasive cervical carcinoma than in preinvasive lesions. This HPV 16 variant possesses a common mutation (T to G) in nucleotide 350 (codon 83) of the E6 gene, resulting in an amino acid shift, L83V, in the E6 protein. This mutation was believed to signify preinvasive cervical lesions with a high probability of progression to invasive carcinoma. The purpose of the present investigation is to describe a rapid method for the detection of this variant HPV 16, E6 (L83V). Paraffin blocks of 18 gynecologic biopsy specimens were collected, all displaying the morphology of cervical intraepithelial neoplasia (CIN I-III) and a positive HPV 16 test. Sections from these blocks were used for DNA extraction. A DNA sequence of the E6 gene containing 176 bases (including codon 83) was amplified by polymerase chain reaction (PCR) and analyzed by non-radioactive single-strand conformational polymorphism (SSCP) analysis. A divergent SSCP pattern was observed in 7 of the HPV 16 positive biopsy specimens. A DNA sequence analysis of the PCR products revealed the conversion of Leu to Val in codon 83 of the E6 gene, correlating to the divergent band pattern. This PCR-SSCP method can be used to test for HPV 16 in women who are at serious risk of developing invasive cervical carcinoma.

Adenocarcinoma↗
PubMed1999

Clonal evolution as judged by immunoglobulin heavy chain gene rearrangements in relapsing precursor-B acute lymphoblastic leukemia.

Oligoclonality and ongoing clonal evolution are common features in patients with precursor-B (pre-B) acute lymphoblastic leukemia (ALL), as judged by immunoglobulin heavy chain (IgH) gene rearrangement analysis. These features are considered to be results of secondary rearrangements after malignant transformation or emergence of new tumor clones. In the present study we analyzed the IgH gene rearrangement status in 18 cases with relapsing pre-B ALL using variable heavy chain (V(H)) gene family specific polymerase chain reaction (PCR) amplification and single stranded conformation polymorphism (SSCP) analysis. Clonal IgH rearrangements were displayed in all leukemias but one, and altered rearrangement patterns occurred in five cases (29%), which were selected for detailed nucleotide sequence analysis. In one case, multiple subclones at diagnosis were suggested to be derived from a progenitor clone through joining of different V(H) germline gene segments to a pre-existing D-J(H) complex (V(H) to D-J(H) joining). Evidence for V(H) gene replacement with identical N-sequences at the V(H)-D junction and a common D-J(H) region was observed in one case. Diversification at the V(H)-D junction consisting of heterogeneous N-sequences were observed in one case. This molecular modification of the V(H)-D region could fit a hypothesized "open-and-shut" mechanism. Nevertheless, despite these ongoing events at least one IgH rearrangement remained unchanged throughout the disease in most patients, indicating that the immunoglobulin heavy chain locus can be a suitable marker for detection of minimal residual disease (MRD).

Base Sequence↗
PubMed1998

Polymerase chain reaction-single-strand conformational polymorphism analysis of antigen receptor rearrangements in monitoring therapeutic effect in childhood ALL.

The rearrangement of the immunoglobulin heavy chain (IgH) genes can be used as a marker of cell lineage and clonality. The polymerase chain reaction (PCR) technique using consensus primers for the IgH gene was used for remission and minimal residual disease (MRD) analysis in the follow-up of childhood acute lymphoblastic leukemia (ALL) of B-cell lineage. Single-strand conformational polymorphism (SSCP) was used to distinguish the specific clonal amplicons from the background. The Authors found that, in a series of 22 patients followed-up for 5.3 to 11.1 years, the PCR-SSCP technique could detect at least one rearrangement at initial diagnosis in 21 (95%). All patients who remained in continuous complete remission were PCR-SSCP negative at remission controls. Ten of the 22 patients had one or more bone marrow relapses. The PCR-SSCP method demonstrated MRD in three of them. In 6 of the 7 (86%) of patients with disease recurrence from whom samples were taken within 6 months before a clinically overt relapse, PCR-SSCP became positive. The Authors conclude that PCR-SSCP of a rearrangement marker might have a role as a convenient technique for monitoring emerging relapse. It may also detect unrelated clones or ongoing secondary recombination events during progression. However, PCR-SSCP is not sensitive enough to detect MRD in all patients in whom disease will later recur.

Bone Marrow Transplantation↗
PubMed1997

Comparative analysis of detection systems for evaluation of PCR amplified immunoglobulin heavy-chain gene rearrangements.

Four different detection systems were compared for evaluation of polymerase chain reaction (PCR) amplified immunoglobulin heavy-chain gene rearrangements in acute lymphoblastic leukemia (ALL) and non-Hodgkin's lymphoma (NHL) of B-cell lineage. In 63.0% of the fragments detected by ethidium bromide stained agarose gel electrophoresis (Agarose-EtBr) the sensitivity was insufficient to separate the specific clonal population from the background of normal B cells. Using polyacrylamide gel electrophoresis (PAGE), PAGE combined with single-strand conformation polymorphism (PAGE-SSCP) and PhastGel-SSCP (Phast-SSCP) analysis with silver staining, the resolution was improved and the majority of the inconclusive amplicons were elucidated. However, Phast-SSCP displayed a slightly higher detection level compared to PAGE and PAGE-SSCP. According to our findings PAGE-SSCP and Phast-SSCP were superior to agarose-EtBr and PAGE in detecting new emerging clones and clonal evolution.

DNA, Neoplasm↗
PubMed1995

A novel human B-cell line (U-2904) bearing t(8;14) and t(14;18) translocations.

Sequential activation of bcl-2 and c-myc appears to be involved in the pathogenesis of rare de novo acute lymphoid leukemias bearing both t(8;14) and t(14;18). Acquisition of t(8;14) by follicular-lymphoma cells with t(14;18) has also been related to the clinical transformation into an overt acute lymphoid leukemia in rare cases reported, and a role for c-myc involvement in the progression of some follicular lymphomas with t(14;18) has been suggested by the detection of c-myc rearrangements in association with histologic transformation. However, c-myc abnormalities different from those observed in Burkitt's lymphoma have been reported in diffuse large-cell lymphomas with breakpoints in 8q24, and a t(8;14) molecularly different from the classical one has been found in follicular lymphomas without t(14;18). We report the preliminary characterization of the EBV-negative cell line U 2904 established from a transformed follicular lymphoma that carries both t(8;14) (q24;q32) and t(14;18) (q32;q21) translocations. U 2904 cells have a mature B-cell phenotype, grow in agarose and are tumorigenic in nude mice. Rearrangements of both c-myc and bcl-2 confirmed the involvement of both oncogenes in the translocations which lead to abundant c-myc and bcl-2 transcripts. Two JH rearrangements and one C alpha rearrangement were observed which did not co-migrate with either c-myc or bcl-2 rearrangements. This is the first report of a cell line bearing both t(8;14) and t(14;18) derived from a follicular lymphoma after documented transformation into a centroblastic lymphoma without leukemic features. U 2904 provides further evidence for the involvement of c-myc in the progression of follicular lymphomas.

Animals↗
PubMed1995

Nonradioactive detection of monoclonal immunoglobulin heavy chain gene rearrangement with PCR-SSCP.

The rearrangement of the immunoglobulin heavy chain gene can be used as a marker of B-cell lineage and clonality. By using polymerase chain reaction (PCR) with variable-region and joining-region specific primers it is possible to detect the rearrangement of a small amount of clonal B cells, as described by several groups. The specific PCR product can be detected after amplification with gel electrophoresis and ethidium bromide staining. The DNA fragments obtained from different clones are, however, approximately of the same size, making it difficult to distinguish between the clones by simple electrophoresis and ethidium bromide staining, as described in many reports. Single-strand conformational polymorphism (SSCP) was evaluated as a method to detect specific clonal amplicons in a mixture of PCR-amplified products. Unique patterns were obtained for different B-cell clones, detectable in mixtures of 0.25% clonal cells in normal cells. It is concluded that SSCP is a valuable method for the specificity control of PCR in B-lymphocyte clonality analyses. The advantages of the described method over previously published techniques are increased specificity, simplicity without radioactivity, and rapidity.

Adult↗
PubMed1994

Epstein-Barr virus (EBV) can immortalize B-cll cells activated by cytokines.

B-type of chronic lymphocytic leukemia (B-CLL) cells are inert to the potent transforming action of Epstein-Barr virus (EBV). The mitogenic action of Staphylococcus aureus Cowan I (SAC), MP6-thioredoxin, and interleukin 2 (IL-2), agents previously shown to induce proliferation in normal as well as in B-CLL cells, lifted this block, and EBV-positive cell lines could be established. It was not possible to establish cell lines of leukemic origin from cultures that were incubated with EBV alone or cytokine mix alone. CLL-cells infected with EBV only, expressed the viral nuclear antigen complex (EBNA), but not the viral latent membrane protein (LMP). They were not activated as measured by cell size and 3H-thymidine incorporation. In contrast, cells incubated with EBV and cytokine mix expressed both EBNA and LMP in parallel with enlargement and increased 3H-thymidine incorporation. These results emphasize that LMP expression is a prerequisite for growth transformation and immortalization and that cytokine activation signals are required for its expression in B-CLLs. Cells incubated with SAC/MP6-thioredoxin/IL-2 did not express any of the viral antigens, but were activated with regard to the mentioned parameters. Nine cell lines were established from six patients. From each of the three patients, we obtained 'twin'-pair lines: one corresponding to the malignant cell and the other to a normal B-lymphoblastoid cell. Thus, malignant and normal B-cell counterparts, from the very same donor, are at hand for comparative studies. The cell lines have been carried out for more than 12 months in culture. We conclude that B-CLL that are refractory to EBV-transformation can be rendered susceptible through in vitro cytokine activation.

Antigens, CD↗
PubMed1991

Expression of the c-myc protein is down-regulated at the terminal stages during in vitro differentiation of B-type chronic lymphocytic leukemia cells.

The translocated c-myc oncogene in Burkitt's lymphoma (BL) and murine plasmacytoma (MPC) has been proposed to be expressed at a stage of differentiation at which the gene is normally silent, resulting in a continuous proliferation and an inhibited terminal differentiation. To determine whether c-myc is differently expressed at the various stages of the differentiation pathway, we used B-type chronic lymphocytic leukemia (B-CLL) cells, representing resting B lymphocytes, inducible to proliferation and/or differentiation in vitro. The c-myc protein, and Ig lambda-light chain and PCA-1 antigen as markers of B-cell maturation, were analyzed in single, morphologically defined cells by immunocytochemical double-staining. The proliferation of individual cells was determined by 3H-thymidine incorporation and by analysis of Ki-67 antigen expression. The results show that the level of c-myc expression correlates to the stage of differentiation and to the proliferative activity. Uninduced resting cells did not express c-myc. The c-myc protein was observed in the highest amount at the proliferative B-lymphoblast stage of maturation and was reduced in plasmablasts and undetectable in plasma cells. The results suggest that maturation of B cells into nonproliferative, terminally differentiated plasma cells is associated with a downregulated c-myc expression and thus support the view that the deregulated c-myc gene in BL and MPC is expressed at an inappropriate stage of maturation and thereby inhibits terminal differentiation.

Antigens, Surface↗
PubMed1988

Management of inflammatory abdominal aortic aneurysm.

Some of the pitfalls in the management of inflammatory abdominal aortic aneurysm are stressed in the presentation of six illustrative cases. Background data on the presumed etiology and common symptoms are provided. The diagnostic value of computed tomography for preoperative detection of the fibrosis surrounding these aneurysms and the differentiation from other conditions are also discussed.

Aged↗
PubMed1987

Boar sperm surface glycoproteins: isolation, localization, and temporal expression during spermatogenesis.

Boar sperm glycoprotein fractions were isolated by Lens culinaris hemagglutinin affinity chromatography of detergent-solubilized ejaculated spermatozoa, followed by preparative sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis. In order to develop methods for further investigations of the sperm proteins, we proceeded with two of the isolated glycoproteins. Antibodies were raised in female rabbits against each of the two sperm glycoproteins. By a combination of immunosorbent chromatography, using the antibodies obtained, and preparative SDS polyacrylamide gel electrophoresis, highly purified sperm proteins were isolated. The sperm proteins were immobilized on Sepharose gel columns and specific immunoglobulin Fab fragments were enriched by affinity chromatography. The specificity of the Fab fragments was ascertained by immunoprecipitation analysis. The Fab fragments were used in indirect immunofluorescence analysis to localize the corresponding antigens on the surface of boar spermatozoa. Both antigens were exclusively confined to the postacrosomal region. Immunohistochemical staining of boar testis sections revealed that both antigens are expressed from the spermatid stage. This technique also revealed that one of the antigens congregated at the Golgi complex-acrosome region during spermatogenesis.

Animals↗
PubMed1987

Neuron-specific enolase expression and neuroendocrine differentiation in carcinomas of the breast.

The concentration of neuron-specific enolase (NSE, gamma-subunit of enolase) in tumor extracts of 25 nonargyrophilic and seven argyrophilic carcinomas of the female breast was measured by radioimmunoassay. The mean concentration of NSE in nonargyrophilic carcinomas was 89 ng/mg of protein, (range, 9 to 281 ng/mg), and the mean concentration of NSE in argyrophilic carcinomas was 153 ng/mg of protein (range, 4 to 420 ng/mg). All carcinomas, irrespective of the silver reaction, could be grouped in regular histopathologic terms. Neuron-specific enolase immunoreactivity in sections of the corresponding fixed tumors occurred in both silver-stained and unreactive tumors, although the reaction was more prominent in the argyrophilic tumors. The results indicate that NSE in considerable amounts may be present in both argyrophilic and nonargyrophilic carcinomas of the breast, although higher concentrations are found most often in the former tumor type.

Aged↗