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Biomedical subjects

I Palva

Publications and source records attributed to I Palva.

At least 19 recordsLinked to original sources
PubMed1999

Response level and survival after conventional chemotherapy for multiple myeloma: a Finnish Leukaemia Group study.

The relation between overall survival time (OS) and response level (CR, 75%R, PR, MR, SD) was analysed in 432 multiple myeloma patients from 4 prospective Finnish Leukaemia group trials, treated with conventional chemotherapy. The primary regimen was either melphalan and prednisolone or combination chemotherapy with melphalan as a main component. Both the influence of the pre-treatment factors in patients with different levels of responses and the aspects related to chemotherapy were analysed. The 324 patients aged up to 70 yr and the 10(8) older patients were dealt with as separate groups. Irrespective of the primary chemotherapy regimen, the level of response was not significantly influencing in the OS time, and this was true in both age categories. The median OS of the patients up to 70 yr of age who had any response was 57 months, compared to the 10 months of those with PD (p < 0.001). The corresponding figures for the older patients were 40 and 4 months (p <0.001), respectively. The pretreatment prognosticators for the patients with minimal responses were not more favourable than for patients with responses at higher levels. The prolonged primary chemotherapy was favourable in patients having responses less than PR. Accordingly, the primary goal of conventional chemotherapy for multiple myeloma is stabilization of disease, not the level of response.

Aged↗
PubMed1996

Measurement of health-related quality of life in multiple myeloma. Nordic Myeloma Study Group.

When a randomized trial (NMSG 4/90) comparing treatment with melphalan/prednisone to melphalan/ prednisone + interferon alpha-2b in newly diagnosed multiple myeloma was initiated in 1990, a quality-of-life assessment was integrated into the study. We used the questionnaire (QLQ-C30) developed by the European Organization of Research and Treatment of Cancer (EORTC) Study Group on Quality of Life. The QLQ-C30 incorporates five functional scales, three symptom scales, a global health and quality-of life scale and some single symptom measures. The questionnaire was completed prior to treatment and after 1, 6, 12, 24, 36 and 48 months. 524 (90.2%) of 581 patients enrolled in the NMSG 4/90 completed the first questionnaire, and 484 (83.3%) completed all questionnaires given to them. All but one of the scales met the minimum criteria of reliability (Cronbach's alpha >/ 0.70). Validity was shown by (1) the ability of the scales to discriminate clearly between patients differing in clinical status as defined by pretreatment W.H.O. performance index and Durie & Salmon stage, and (2) the sensitivity to changes in objective disease status (response and relapse). This is the first report of the measurement of health-related quality of life in a prospective clinical trial in multiple myeloma. The results demonstrate that the QLQ-C30 is a reliable and valid instrument for the measurement of quality of life in these patients. The data will be used for a cost-utility analysis of the results of the NMSG 4/90 trial.

Aged↗
PubMed1994

Hormone-sensitive lipase is closely related to several bacterial proteins, and distantly related to acetylcholinesterase and lipoprotein lipase: identification of a superfamily of esterases and lipases.

We have sequenced a gene from Bacillus acidocaldarius which encodes an open reading frame (ORF3) of 310 amino acids. The ORF3 was found to be related to the mammalian hormone-sensitive lipase (HSL). Searching the protein data base revealed five other bacterial proteins related to the HSL. Upon further sequence comparisons this HSL-group was found to be related to the family of carboxylesterases, and to a family of lipases (lipoprotein, hepatic and pancreatic lipases). The evolutionary relationship of these serine-dependent hydrolytic enzymes has not been studied previously, and it has not been known that these proteins belong to the same superfamily. Finally, the alignment of the HSL with the bacterial proteins allowed us to infer the location of the hormone-sensitive regulatory domain of the HSL-protein.

Acetylcholinesterase↗
PubMed1993

Cloning and sequencing of a gene encoding acidophilic amylase from Bacillus acidocaldarius.

Two starch-degrading enzymes produced by Bacillus acidocaldarius (renamed as Alicyclobacillus acidocaldarius) were identified. According to SDS-PAGE, the apparent molecular masses of the enzymes were 90 and 160 kDa. Eight peptide fragments and the N-terminal end of the 90 kDa polypeptide were sequenced. An oligonucleotide, based on the amino acid sequence of a peptide fragment of the 90 kDa protein, was used to screen a lambda gt10 bank of B. acidocaldarius, and the region encoding the 90 kDa protein was cloned. Unexpectedly, the ORF continued upstream of the N terminus of the 90 kDa protein. The entire ORF was 1301 amino acids (aa) long (calculated molecular mass 140 kDa) and it was preceded by a putative ribosomal binding site and a promoter. Computer analysis showed that the 1301 aa protein was closely related to an alpha-amylase-pullulanase of Clostridium thermohydrosulfuricum. We suggest that the starch-degrading 160 kDa protein of B. acidocaldarius is an alpha-amylase-pullulanase, and the 90 kDa protein is a cleavage product of the 160 kDa protein. Another ORF, apparently in the same transcription unit, was found downstream from the amylase gene. It encoded a protein that was closely related to the maltose-binding protein of Escherichia coli.

ATP-Binding Cassette Transporters↗
PubMed1993

Protein secretion in Bacillus species.

Bacilli secrete numerous proteins into the environment. Many of the secretory proteins, their export signals, and their processing steps during secretion have been characterized in detail. In contrast, the molecular mechanisms of protein secretion have been relatively poorly characterized. However, several components of the protein secretion machinery have been identified and cloned recently, which is likely to lead to rapid expansion of the knowledge of the protein secretion mechanism in Bacillus species. Comparison of the presently known export components of Bacillus species with those of Escherichia coli suggests that the mechanism of protein translocation across the cytoplasmic membrane is conserved among gram-negative and gram-positive bacteria differences are found in steps preceding and following the translocation process. Many of the secretory proteins of bacilli are produced industrially, but several problems have been encountered in the production of Bacillus heterologous secretory proteins. In the final section we discuss these problems and point out some possibilities to overcome them.

Amino Acid Sequence↗
PubMed1992

Randomised, placebo-controlled multicentre trial of clodronate in multiple myeloma. Finnish Leukaemia Group.

Osteolytic lesions and pathological fractures are common in multiple myeloma. Because clodronate inhibits osteoclastic resorption, we did a randomised, controlled trial in 350 patients from 23 hospitals. All patients received standard melphalan-prednisolone, and were randomised to receive clodronate 2.4 g daily or placebo for 24 months. The proportion of patients with progression of osteolytic bone lesions was twice as high in the placebo group (n = 168 at baseline) than in the clodronate group (n = 168 at baseline) in an intention-to-treat analysis (24 vs 12%, p = 0.026). Progression of vertebral fractures was lower in the clodronate group, but the difference was not significant (30 vs 40%). Serum calcium and urinary calcium excretion decreased significantly in both groups, but the changes were greater in the clodronate group. The percentage of patients feeling no pain increased more in the clodronate group (from 24 to 54%, p < 0.001) than in the placebo group (from 29 to 44%, p < 0.01). Side-effects were similar in both groups. We conclude that clodronate is an effective and safe adjunct in the management of multiple myeloma. The drug delays osteolytic bone lesions, reduces the degree of hypercalcaemia and hypercalciuria, and decreases pain.

Aged↗
PubMed1992

Expression of the Erwinia carotovora polygalacturonase-encoding gene in Bacillus subtilis: role of signal peptide fusions on production of a heterologous protein.

The pehA gene encoding an endopolygalacturonase (pectinase) of Erwinia carotovora subsp. carotovora has been cloned previously [Saarilahti et al., Mol. Microbiol. 4 (1990) 1037-1044]. We expressed pehA in Bacillus subtilis using a secretion vector based on the promoter and signal sequence of the alpha-amylase (Amy)-encoding gene, amyE, from Bacillus amyloliquefaciens. To test whether the location of the junction between the secretion vector and pehA affects the protein yield, we made four different junctions. Two constructs contained an intact Amy signal sequence, whereas the other two were fusions between the Amy signal sequence and the polygalacturonase (PG) signal sequence. There was approximately fourfold variation in the production efficiency of B. subtilis strains carrying the different constructs. The most efficient construct contained the N-terminal and hydrophobic regions of the Amy signal peptide joined to the C terminus of PG signal peptide. This construct produced, in a shake flask culture, 0.8 g of polygalacturonase per liter of growth medium. In a pulse-chase experiment, the signal peptide of the most efficient construct was rapidly cleaved while cleavage was slow in the other constructs. Our results suggest that fusions containing intact signal peptides, which are common when producing foreign proteins, are not necessarily the most efficient.

Amino Acid Sequence↗
PubMed1992

Improving the production of E. coli beta-lactamase in Bacillus subtilis: the effect of glucose, pH and temperature on the production level.

Bacillus subtilis has been considered a promising host for the production of foreign proteins. However, proteases released by the host organism can often cause rapid breakdown of secreted heterologous proteins. Here we report that the addition of 6% glucose and 100 mM potassium phosphate to the growth medium significantly reduces the degradation of E. coli TEM beta-lactamase secreted from B. subtilis, when applying an expression system based on B. amyloliquefaciens alpha-amylase. The yield of beta-lactamase was increased 10-20-fold when compared to the yield in Luria medium. The promoter of B. amyloliquefaciens alpha-amylase gene is repressed by glucose. However, here we show that the repression does not take place in a multicopy plasmid, thus enabling our approach to efficiently reduce the protease action by catabolite repression. We have also studied the role of pH and temperature on the beta-lactamase production in laboratory scale bioreactors. Low temperature and low pH are both favorable for a high level beta-lactamase production by the high copy plasmid construction.

Bacillus subtilis↗
PubMed1992

Bolus therapy with mitoxantrone and vincristine in combination with high-dose prednisone (NOP-bolus) in resistant multiple myeloma. Nordic Myeloma Study Group (NMSG).

In a phase II study, 58 patients with resistant multiple myeloma (MM) were treated with a combination chemotherapy (NOP-bolus regimen) consisting of mitoxantrone (16 mg/m2 for the first 25 patients and 12 mg/m2 for the subsequent 33), vincristine (2 mg), both as bolus injections on day 1 and prednisone (250 mg/d on d 1-4 and 17-20). In patients greater than 70 years of age, the mitoxantrone dose was reduced to 12 mg/m2 or 8 mg/m2, respectively. The treatment was repeated every 4 weeks. A response (greater than 50% reduction in M component) was obtained in 26% of the patients and a minor response (clinical improvement but less than 50% reduction in M component) in another 21%. Median response duration was 27 wk and median survival for all patients was 25 wk. There were no differences in response rate or duration between patients receiving the high or low mitoxantrone dose, but patients in the low-dose group had fewer serious infections.

Adult↗
PubMed1992

S-layer protein gene of Lactobacillus brevis: cloning by polymerase chain reaction and determination of the nucleotide sequence.

The surface (S)-layer protein of Lactobacillus brevis was isolated, purified, and characterized. The S-layer protein is the major protein of the cell, with an apparent molecular mass of 46 kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Immunogold electron microscopy with polyclonal antiserum against the isolated 46-kDa protein was used to confirm the surface location of this protein. N-terminal amino acid sequences of the intact 46-kDa protein and its tryptic peptides were determined. The gene of the S-layer protein was amplified from the genome of L. brevis by polymerase chain reaction with oligonucleotides, synthesized according to the N-terminal amino acid sequences, as primers. The polymerase chain reaction fragments containing the entire S-layer gene and its regulatory regions were sequenced. Nucleic acid sequence analysis revealed one open reading frame with a capacity to encode a protein of 48,159 Da. From the regulatory region of the gene, two subsequent promoters and a ribosome binding site, showing typical features of prokaryotic consensus sequences, were found. The coding region contained a characteristic gram-positive-type signal peptide of 30 amino acids. Removal of the signal peptide results in a polypeptide of 435 amino acids, which is in excellent agreement with the size of the S-layer protein determined by SDS-PAGE. The size and the 5' end analyses of the S-layer transcripts confirmed the monocistronic nature of the S-layer operon and the functionality of the two promoters found.

Amino Acid Sequence↗
PubMed1991

Nucleotide sequence of the secY gene from Lactococcus lactis and identification of conserved regions by comparison of four SecY proteins.

Sec Y is an integral membrane protein which participates in the translocation of proteins through the bacterial cell membrane. We have cloned the sec Y gene of Lactococcus lactis, and found its deduced protein sequence, 439 amino acids long, to be similar in length to the previously determined Sec Y proteins of Escherichia coli, Bacillus subtilis and Mycoplasma capricolum. Comparison of the L. lactis Sec Y to the 3 other Sec Y proteins revealed 90 conserved amino acid residues (21%). Nearly half of the conserved residues are clustered in 2 of the 10 transmembrane segments, and in 2 of the 6 cytoplasmic regions. Some of the conserved regions are apparently responsible for the interactions of Sec Y with signal sequences, and the proteins SecE and SecA.

Amino Acid Sequence↗
PubMed1991

Production of pectin methylesterase from Erwinia chrysanthemi B374 in Bacillus subtilis.

The gene coding for pectin methylesterase (PME) of Erwinia chrysanthemi B374 (pme) was cloned by a polymerase chain reaction. The pme gene was expressed in Bacillus subtilis using a secretion vector based on the promoter and signal sequence of the alpha-amylase gene from B. amyloliquefaciens. The cultivation of B. subtilis cells carrying the cloned pme resulted in efficient secretion of PME into the culture medium based on enzymatic and sodium dodecyl sulphate-poly-acrylamide gel electrophoresis characterizations. The NH2-terminal sequence analysis of the secreted PME revealed two different NH2-termini. Heterologous processing was probably due to a second putative signal peptidase cleavage site at the joint region between the PME and alpha-amylase signal peptide.

Bacillus subtilis↗
PubMed1991

Refractory myelomatosis treated with mitoxantrone in combination with vincristine and prednisone (NOP-regimen): a phase II study. The Nordic Myeloma Study Group (NMSG)

In a phase II study, patients with refractory myelomatosis were treated with a combination chemotherapy (NOP regimen): mitoxantrone (bolus injection of 4 mg/m2 on days 1-4), vincristine (continuous infusion of 0.4 mg/24 h on days 1-4) and prednisone (250 mg/d on days 1-4 and 17-20). The treatment was repeated every 4 weeks. Ninety-two patients were treated after they were found refractory to treatment with melphalan and prednisone (and occasionally vincristine) (n = 50) or more intensive treatment regimens (n = 42) including anthracyclines (n = 18). Response (greater than or equal to 50% reduction of M protein) was obtained in 23 patients and minor response (clinical improvement but less than 50% reduction in M protein) in 22 patients. The median duration of the response was 7.5 months. Equal response rates were observed irrespective of the type of previous treatment. The major toxicity was myelosuppression with severe granulocytopenia and infections. However, the frequency decreased throughout the cycles. The NOP treatment is recommended in refractory myelomatosis, especially in patients refractory to other intensive regimens. Patients in a poor clinical condition or with thrombocytopenia before treatment should have a reduced mitoxantrone dose in the first treatment cycles.

Adult↗
PubMed1991

Isolation and characterization of Lactococcus lactis subsp. lactis promoters.

DNA fragments with promoter activity were isolated from the chromosome of Lactococcus lactis subsp. lactis. For the isolation, a promoter probe vector based on the cat gene was constructed, which allowed direct selection with chloramphenicol in Bacillus subtilis and L. lactis. Four of the putative promoters (P1, P2, P10, and P21) were analyzed further by sequencing, mapping of the 5' end of the mRNA, Northern (RNA blot) hybridization, and chloramphenicol acetyltransferase activity measurements. From these fragments, -10 and -35 regions resembling the consensus Escherichia coli sigma 70 and B. subtilis sigma 43 promoters were identified. Another set of promoters, together with a signal sequence, were also isolated from the same organism. These fragments promoted secretion of TEM beta-lactamase from L. lactis. When the two sets of promoters were compared, it was found that the ones isolated with the cat vector were more efficient (produced more mRNA). By changing the promoter part of the promoter-signal sequence fragment giving the best TEM beta-lactamase secretion into a more efficient one (P2), a 10-fold increase in enzyme production was obtained.

Base Sequence↗
PubMed1991

Secretion of TEM beta-lactamase with signal sequences isolated from the chromosome of Lactococcus lactis subsp. lactis.

With TEM beta-lactamase as a reporter gene, a set of expression-secretion-promoting fragments were isolated from the chromosome of Lactococcus lactis subsp. lactis. The fact that only translocated beta-lactamase renders cells resistant to ampicillin allowed direct ampicillin selection with an Escherichia coli vector (pKTH33). The clones showing the greatest ampicillin resistance were subcloned onto a replicon capable of replication in lactic acid bacteria (pVS2), and the nucleotide sequences of the relevant fragments were determined. The structure of the secretion-promoting fragments in general resembled that of gram-positive true signal sequences, with a strongly positively charged N terminus, a long hydrophobic core, and a putative signal peptidase recognition site. The promoterlike sequences preceding the signal sequences matched well with those of previously published lactococcal promoters. In addition to E. coli, the functioning of these expression-secretion cassettes was studied in three gram-positive hosts: Bacillus subtilis, L. lactis, and Lactobacillus plantarum. Efficient expression and secretion of TEM beta-lactamase into the culture medium of each gram-positive host was obtained. Furthermore, when a strain of L. lactis subsp. lactis showing increased sensitivity to lysozyme was compared with a standard laboratory strain, threefold-higher secreted enzyme activities were detected.

Amino Acid Sequence↗
PubMed1990

Production and secretion of pertussis toxin subunits in Bacillus subtilis.

Pertussis toxin (PT) is a major component of today's acellular whooping cough vaccines. The use of acellular vaccines is predicted to increase sharply in the near future. There is therefore a need to produce PT in a way that makes its purification as easy as possible. Our approach was to express all five PT subunits individually in Bacillus subtilis. We have used vectors containing the promoter and signal sequences of the alpha-amylase gene of Bacillus amyloliquefaciens followed by an insert encoding the appropriate PT-subunit. All PT-subunits were secreted and found in the culture supernatant. The level of expression varied considerably: S1 and S5 were produced in large quantities whereas much smaller amounts of S2, S3 and S4 were found. The subunits were also present in the membrane fraction of the respective strains.

Amino Acid Sequence↗
PubMed1990

Structural analysis of the pehA gene and characterization of its protein product, endopolygalacturonase, of Erwinia carotovora subspecies carotovora.

A clone producing a polygalacturonase (EC 3.2.1.15) in Escherichia coli was isolated from a genomic library of Erwinia carotovora subspecies carotovora constructed in PUC18. The DNA segment carrying the corresponding structural gene, named pehA, contained an open reading frame (ORF) encoding a 402-amino-acid (aa) polypeptide with an Mr of 42,849. In E. carotovora the polygalacturonase was synthesized with a 26-aa cleavable signal peptide. The mature 376-aa PehA had a calculated Mr of 40,064 and a pl of 10.19. The pH optimum of the enzyme was about 5.5 and the temperature optimum was in the range 35-45 degrees C. Analysis of the reaction products of polygalacturonic acid hydrolysis indicated that the PehA protein is an endopolygalacturonase. No similarity was observed between the aa sequences of PehA and other pectic enzymes of erwinias. However, substantial similarity was detected within the C-terminal portions of PehA and a previously described tomato polygalacturonase, suggesting that the bacterial and eukaryotic polygalacturonases may have a common origin.

Amino Acid Sequence↗