Biomedical subjects

K Mäkinen

Publications and source records attributed to K Mäkinen.

At least 19 recordsLinked to original sources

PubMed2005

Functional outcome of distal bypasses for lower limb ischemia.

OBJECTIVES: The purpose of this study was to assess limb salvage and functional outcome in patients who underwent distal reconstructions. DESIGN: Retrospective study. MATERIALS AND METHODS: Fifty-nine consecutive patients underwent 63 femorodistal bypass operations during 1998-2002 at a university hospital. Late functional outcome was assessed using a questionnaire (mean 27 months after the primary operation). RESULTS: At the end of the study, 81% (30/37) of the surviving patients were alive with a viable limb. In all, 90% (27/30) of patients were living in their own homes and 3% (1/30) in a nursing home. Sixty percent (18/30) were able to walk independently. The walking distance was unlimited in 42% (13/31) and limited in 42% (13/31) of the operated limbs. In 16% (5/31) of cases, the treated limbs served only as a support. CONCLUSIONS: According to our results, the functional outcome of distal bypasses seems to be favourable. It is recommended that these operations should be performed even in elderly patients to avoid major amputations and to maintain the independence of the patient.

Adult↗

PubMed2003

Angiogenesis--a new goal in peripheral artery occlusive disease therapy.

The vasculature is mostly quiescent in the normal adult, with the exception of the growth of new blood vessels during the female reproductive cycle. Recent advances in the knowledge concerning the molecular changes and the identification of genetic events in this vascular quiescence, as well as in vascular growth, has led to an increasing number of studies in which these phenomena are manipulated. Angiogenesis is the growth of new vessels from existing ones. Although new vessel formation is involved in many pathologic situations, like tumour growth, therapeutic angiogenesis has been presented as a novel method for the treatment of ischemic diseases, like peripheral arterial occlusive disease (PAOD). In experimental studies therapeutic angiogenesis has been produced by recombinant growth-factor protein application as well as by growth factor gene therapy. Most widely studied factors belong to vascular endothelial growth factor (VEGF) or fibroblast growth factor (FGF) families. Studies have also shown that, angiogenic growth factors stimulate endothelial cell migration and accelerate endothelial repair by enhancing post-injury re-endothelization. In clinical studies angiogenic therapy has been evaluated in patients with severe vascular diseases. The results have revealed that therapy is well tolerated as well as safe and that angiogenic therapy has a clear biologic effect. However, controlled studies are still needed to answer the question whether therapeutic angiogenesis offers a real clinical benefit to patients with PAOD.

Adult↗

PubMed2001

Phosphorylation down-regulates the RNA binding function of the coat protein of potato virus A.

Plant viruses encode movement proteins (MPs) to facilitate transport of their genomes from infected into neighboring healthy cells through plasmodesmata. Growing evidence suggests that specific phosphorylation events can regulate MP functions. The coat protein (CP) of potato virus A (PVA; genus Potyvirus) is a multifunctional protein involved both in virion assembly and virus movement. Labeling of PVA-infected tobacco leaves with [(33)P]orthophosphate demonstrated that PVA CP is phosphorylated in vivo. Competition assays established that PVA CP and the well characterized 30-kDa MP of tobacco mosaic virus (genus Tobamovirus) are phosphorylated in vitro by the same Ser/Thr kinase activity from tobacco leaves. This activity exhibits a strong preference for Mn(2+) over Mg(2+), can be inhibited by micromolar concentrations of Zn(2+) and Cd(2+), and is not Ca(2+)-dependent. Tryptic phosphopeptide mapping revealed that PVA CP was phosphorylated by this protein kinase activity on multiple sites. In contrast, PVA CP was not phosphorylated when packaged into virions, suggesting that the phosphorylation sites are located within the RNA binding domain and not exposed on the surface of the virion. Furthermore, two independent experimental approaches demonstrated that the RNA binding function of PVA CP is strongly inhibited by phosphorylation. From these findings, we suggest that protein phosphorylation represents a possible mechanism regulating formation and/or stability of viral ribonucleoproteins in planta.

Binding, Competitive↗

PubMed2001

Identification of the genome-linked protein in virions of Potato virus A, with comparison to other members in genus Potyvirus.

Viruses of the genus Potyvirus, the largest genus of plant-infecting viruses, have a messenger-polarity ssRNA genome encapsidated by approximately 2000 units of the viral coat protein (CP), resulting in filamentous virions. Only few studies have examined potyvirus virions for the presence of other structural proteins. A protein linked covalently to the 5'-end of the genome has been identified in Tobacco vein mottling virus (TVMV) and Tobacco etch virus (TEV). In TEV, it is either the viral NIa protein or only its N-terminal domain (VPg) separated autocatalytically from the C-terminal proteinase domain (NIa-Pro). Virions of TVMV carry only the VPg. We examined virions of Potato virus A (PVA) for the genome-linked protein using immunoblotting or iodination and immunoprecipitation. The VPg ( approximately 25 kDa) only, and not the unprocessed NIa, was detected. Another signal corresponding to approximately 49 kDa was detected in disrupted, RNase-treated virions with anti-VPg antibodies but not with antibodies to NIa-Pro. Since it possibly represented a dimeric form of the VPg, self-interaction of the VPg was tested using the yeast two-hybrid system, which showed that the VPg self-interacts in the absence of viral RNA.

Immunoblotting↗

PubMed2001

Cell-to-cell movement of potato virus X involves distinct functions of the coat protein.

Complementation of movement-deficient potato virus X (PVX) coat protein (CP) mutants, namely PVX.CP-Xho lacking the 18 C-terminal amino acid residues and PVX.DeltaCP lacking the entire CP gene, was studied by transient co-expression with heterologous proteins. These data demonstrated that the potyvirus CPs and both the major and minor CPs of beet yellows closterovirus could complement cell-to-cell movement of PVX.CP-Xho but not PVX.DeltaCP. These data also indicated that the C-terminally truncated PVX CP lacked a movement function which could be provided in trans by the CPs of other filamentous viruses, whereas another movement determinant specified by some region outside the most C-terminal part of the PVX CP could not be complemented either by potyvirus or closterovirus CPs. Surprisingly, the CP of spherical cocksfoot mottle sobemovirus rescued all of the PVX CP movement functions, complementing the spread of PVX.CP-Xho and, to a lesser extent, PVX.DeltaCP. Both these mutants were also rescued by the tobacco mosaic virus (TMV) movement protein (MP). To shed light on the movement function of PVX CP, attempts were made to complement PVX.CP-Xho by a series of TMV MP mutants. An internal deletion abolished complementation, suggesting that the internal region of TMV MP, which includes a number of overlapping functional domains important for cell-to-cell transport, provides an activity complementing movement determinant(s) specified by the C-terminal region of PVX CP.

Biological Transport↗

PubMed2000

Complementation of the movement-deficient mutations in potato virus X: potyvirus coat protein mediates cell-to-cell trafficking of C-terminal truncation but not deletion mutant of potexvirus coat protein.

The cell-to-cell movement of the GUS-tagged potato virus X (PVX) coat protein (CP) movement-deficient mutant was restored by potyviral CPs of potato virus A (PVA) and potato virus Y (PVY) in Nicotiana benthamiana leaves in transient cobombardment experiments. Viral cell-to-cell movement of PVX CP mutant was complemented in Nicotiana tabacum cv. SR1 transgenic plants expressing PVY CP: PVX RNA and polymerase were detected in the PVX CP mutant-inoculated leaves of transgenic plants. These findings demonstrated the ability of the PVX CP-deficient mutant to move from cell to cell but not long distances in the transgenic plants and suggest that CPs of potex- and potyviruses display complementary activities in the movement process. Potyviral CP alone is not able to carry out these activities, since the mutated PVX CP is indispensable for restored movement. No trans-encapsidation between potyviral CP and PVX RNA was observed. Therefore, potyviral CP facilitates the PVX CP mutant movement by the mechanism that cannot be explained by coat protein substitution. Our data also suggest that CP functioning in cell-to-cell movement is not restricted to a simple passive role in forming virions.

Biolistics↗

PubMed2000

Catheter-mediated vascular endothelial growth factor gene transfer to human coronary arteries after angioplasty.

Blood vessels are among the easiest targets for gene therapy. However, no data are available about the safety and feasibility of intracoronary gene transfer in humans. We studied the safety and efficacy of catheter-mediated vascular endothelial growth factor (VEGF) plasmid/liposome (P/L) gene transfer in human coronary arteries after percutaneous translumenal coronary angioplasty (PTCA) in a randomized, double-blinded, placebo-controlled study. The optimized angioplasty/gene delivery method was previously shown to lead to detectable VEGF gene expression in human peripheral arteries as analyzed from amputated leg samples. Gene transfer to coronary arteries was done with a perfusion-infusion catheter, using 1000 microg of VEGF or beta-galactosidase plasmid complexed with 1000 microl of DOTMA:DOPE liposomes. Ten patients received VEGF P/L, three patients received beta-galactosidase P/L, and two patients received Ringer lactate. Gene transfer to coronary arteries was feasible and well tolerated. Except for a slight increase in serum C-reative protein in all study groups, no adverse effects or abnormalities in laboratory parameters were detected. No VEGF plasmid or recombinant VEGF protein was present in the systemic circulation after the gene transfer. In control angiography 6 months later, no differences were detected in the degree of coronary stenosis between treatment and control groups. We conclude that catheter-mediated intracoronary gene transfer performed after angioplasty is safe and well tolerated and potentially applicable for the prevention of restenosis and myocardial ischemia.

Adult↗

PubMed2000

Regulation of -1 ribosomal frameshifting directed by cocksfoot mottle sobemovirus genome.

The polyprotein of Cocksfoot mottle virus (CfMV) is encoded by two overlapping open reading frames (ORFs). The putative replicase of CfMV is produced as a part of the polyprotein from ORF2b by the -1 ribosomal frameshifting mechanism. The signals leading to -1 ribosomal frameshifting directed by CfMV RNA are the slippery heptamer UUUAAAC and a stem-loop structure starting seven nucleotides downstream from the heptamer. We studied the effect of different parts of the CfMV genome on the -1 ribosomal frameshifting efficiency using a wheat germ extract transcription/translation system. A point mutation in the slippery heptamer and a mutation deleting the stem-loop structure prevented frameshifting. Seventy nucleotides of CfMV sequence, including the slippery sequence and the stem-loop structure, was found to act as a minimal region for frameshifting. Interestingly, a termination codon introduced into the -1-frame 27 nucleotides downstream of the stem-loop structure increased frameshift efficiency threefold, while a similarly located termination codon in the 0-frame had no effect. Even fourfold to fivefold efficiencies were observed when the polyprotein encoding ORFs were fused together, which led simultaneously to the formation of a termination codon downstream of the frameshift signal. Possible reasons underlying these observations are discussed.

Base Sequence↗

PubMed2000

The growth pattern and microvasculature of pancreatic tumours induced with cultured carcinoma cells.

Pancreatic cancer is one of the most frustrating problems in gastroenterological surgery, since there is little we can do to improve the survival of patients with current treatment strategies. If one is to elucidate factors related to carcinogenesis, tumour biology, diagnostics and new treatment modalities of this malignant disease, then it is essential to develop a suitable animal model. In the present study we investigated rat pancreatic tumour growth after intrapancreatic injection of cultured pancreatic carcinoma cells (DSL-6A/C1), originally derived from an azaserine-induced tumour, as well as the features of tumour microcirculation using the microangiography technique. After intrapancreatic inoculation, tumours were detected in 64% of animals. A 1 cm3 tumour volume was reached within 20 weeks after inoculation. The tumours were ductal adenocarcinomas. Larger tumours showed invasive growth and spreading into the surrounding tissues, mainly into spleen and peritoneum. Microangiography revealed that the pancreatic tumours had an irregular and scanty vessel network and there were avascular areas in the center of the tumour. The area between normal pancreas and the induced tumour had dense vascularization. Intrapancreatic tumour induction with cultured pancreatic carcinoma cells produced a solid and uniformly growing tumour in Lewis rats and it thus provides a possible model for pancreatic cancer studies.

Animals↗

PubMed2000

Adenovirus-mediated gene transfer into an experimental pancreatic tumour.

BACKGROUND AND AIMS: Gene therapy has been suggested as a novel approach against pancreatic cancer, a disease with a grim prognosis with current modes of therapy. Despite recent advances in in vitro and experimental in vivo studies, there is no data available concerning gene transfer efficiency in intrapancreatic tumours in immunocompetent animal models. MATERIAL AND METHODS: In in vitro studies rat pancreatic carcinoma cells (DSL-6A/C1) were transduced with replication-deficient adenovirus carrying Escherichia Coli beta-galactosidase (lacZ) gene. Gene transfer efficacy was assessed at different multiplicities of infection (MOIs). Pancreatic tumours were induced by inoculating cultured DSL-6A/C1 cancer cells into Lewis rat pancreases. Established tumours were transduced and three days post-transduction, pancreatic tumours as well as other intra-abdominal organs were harvested and processed for histological analyses, including staining for marker gene expression. RESULTS AND CONCLUSIONS: In vitro assays showed that DSL-6A/C1 cells were transduced efficiently, even at low MOIs. In vivo gene transfer was successful in all animals, and all pancreatic samples showed reporter gene expression. Positive cells were detected in the peritumoural areas as well as to a lesser extent within the tumours. The transgene activity was not evenly distributed and the gene transfer efficiency varied from a few detectable blue cells to 11% per field. Our studies demonstrated safe in vivo gene transfer into intrapancreatic tumours, suggesting that pancreatic tumours are potential targets for in vivo delivery of therapeutic genes.

Adenoviruses, Human↗

PubMed1999

A novel function for a ubiquitous plant enzyme pectin methylesterase: the host-cell receptor for the tobacco mosaic virus movement protein.

Plant virus-encoded movement proteins promote viral spread between plant cells via plasmodesmata. The movement is assumed to require a plasmodesmata targeting signal to interact with still unidentified host factors presumably located on plasmodesmata and cell walls. The present work indicates that a ubiquitous cell wall-associated plant enzyme pectin methylesterase of Nicotiana tabacum L. specifically binds to the movement protein encoded by tobacco mosaic virus. We also show that pectin methylesterase is an RNA binding protein. These data suggest that pectin methylesterase is a host cell receptor involved in cell-to-cell movement of tobacco mosaic virus.

Base Sequence↗

PubMed1999

Stability of native and cross-linked crystalline glucose isomerase.

Stabilities of native and cross-linked crystalline forms of Streptomyces rubiginosus glucose isomerase were compared in buffer and in 45% glucose/fructose solutions. The cross-linked crystalline form of the enzyme was more stable in the presence of substrate while in a buffer solution the native enzyme was more stable. Inactivation of native enzyme in buffer did not obey first-order kinetics but proceeded with a rapid first phase followed by a stable phase. This stabilization is interpreted to be a result of a conformational change in the protein structure. Inactivation of the native enzyme in buffer was directly related to protein precipitation. In the presence of high substrate concentration, the inactivation was related to browning reactions between the enzyme and the reactive sugar, resulting in soluble sugar-protein complexes.

Aldose-Ketose Isomerases↗

PubMed1999

Virus-specific capping of tobacco mosaic virus RNA: methylation of GTP prior to formation of covalent complex p126-m7GMP.

In capping cellular mRNAs, a covalent GMP-enzyme intermediate leads to formation of G(5')ppp(5')N at the 5' end of the RNA, which is modified by methylation catalyzed by guanine-7-methyltransferase. Here we show that isolated membranes from tobacco mosaic virus (TMV)-infected plant or insect cells expressing TMV replicase protein p126, synthesized m7GTP using S-adenosylmethionine (AdoMet) as the methyl donor, and catalyzed the formation of a covalent guanylate-p126 complex in the presence of AdoMet. The methyl group from AdoMet was incorporated into p126, suggesting that the complex consisted of m7GMP-p126. Thus, TMV and alphaviruses, despite their evolutionary distance, share the same virus-specific capping mechanism.

Amino Acid Sequence↗

PubMed1999

Identification of genes encoding for the cocksfoot mottle virus proteins.

Cocksfoot mottle sobemovirus (CfMV) has a monopartite single-stranded positive-sense RNA genome. In wheat germ extract, in vitro translation of CfMV virion RNA resulted in the production of four major proteins of 100, 71, 34 and 12 kDa. In this paper we show the individual genes from which these polypeptides are synthesised. Polyclonal antisera against the proteins encoded by all open reading frames (ORFs) of CfMV were produced. Antibodies were used to immunoprecipitate the in vitro translation products of CfMV genomic RNA as well as the coupled in vitro transcription/translation products of individual viral genes. We demonstrate that the 12, 71, and 100 kDa CfMV proteins are synthesised from the bicistronic genomic RNA of the virus. The CfMV 12 kDa protein is produced from ORF1, the 71 kDa protein from ORF2a (and does not result from the proteolytic cleavage of the polyprotein) and the 100 kDa protein is a polyprotein encoded by ORFs 2a and 2b by a -1 ribosomal frameshift. ORF2b alone does not direct any in vitro protein synthesis. CfMV 34 kDa protein is a coat protein synthesised from the virion-packed subgenomic RNA. The translational strategies of different sobemoviruses are also discussed in this paper.

Animals↗

PubMed1998

Adenovirus-mediated gene transfer to lower limb artery of patients with chronic critical leg ischemia.

Arterial gene transfer offers a promising new approach for the treatment of vascular disorders. However, no data are available about the gene transfer efficiency in human arteries in vivo. The aim of this study was to evaluate the safety and feasibility of catheter-mediated adenoviral gene transfer in human peripheral arteries. Ten patients (8 females, 2 males, mean age 80 +/- 8 years) suffering from chronic critical leg ischemia with a prior decision for amputation were recruited in the study. Gene transfer was performed in eight patients in conjunction with a conventional percutaneous transluminal angioplasty, using a perfusion coil balloon catheter. Two patients served as controls. Increasing concentrations of replication-deficient adenoviruses (titers from 1 x 10(8) to 4 x 10(10) PFU) containing a nuclear-targeted beta-galactosidase marker gene were administered into the arteries over 10 min via the catheter. Amputations were performed 20 to 51 hr after the procedures and gene transfer efficiency was evaluated in the transduced arteries using X-Gal staining for beta-galactosidase activity. Beta-galactosidase gene transfer was well tolerated and no adverse tissue responses or systemic complications were observed in any of the patients. Gene transfer was successful in six of the eight patients. Gene transfer efficiency varied between 0.04 and 5.0% of all arterial cells. Transgene expression was detected in smooth muscle cells, endothelial cells, and macrophages and in tunica adventitia. However, transgene activity was not evenly distributed in the arterial wall and no transgene activity was found beneath advanced atherosclerotic lesions. The safety and feasibility of in vivo gene transfer by adenoviral vectors to human peripheral arteries were established. Although improvements are still required in gene transfer efficiency, these findings suggest that adenoviruses can be used to deliver therapeutically active genes into human arteries.

Adenoviridae↗

PubMed1998

Azaserine-induced rat pancreas tumor model with transplantable cultured cells.

The purpose of this study was to describe the inoculation technique and patterns of growth as well as to characterize typical histological features of Lewis rat subcutaneous and intrapancreatic tumors, induced by inoculation of cultured pancreatic cancer cells (DSL-6A/C1). Subcutaneous inoculation of cultured cells produced a solid tumor that was a locally invasive, well- to moderately differentiated ductal adenocarcinoma. Tumor take was 100% in animals 5 weeks of age; tumor growth was consistent and predictable and a tumor volume of approximately 1 cm3 was reached in 8 weeks. After intrapancreatic transplantation the tumors showed the same histological features as subcutaneous tumors. During inoculation carcinoma cells easily spread around the injected area, and after 2 weeks both pancreatic tumors and superficially infiltrating carcinomas were found in the liver and spleen and around the peritoneum. Tumor take was 60% and tumor growth was somewhat indefinite and unpredictable in the pancreas. However, by reducing the injected carcinoma cell volume and solving the technical problems, 100% tumor take was achieved. The tumor volume reached 2 mm3 during 2 weeks and larger tumors showed a tendency for invasion. According to our results, subcutaneous as well as intrapancreatic tumor induction with cultured cells offers a model for pancreatic cancer studies.

Adenocarcinoma↗

PubMed1997

The importance of fluorescence distribution and kinetics of ALA-induced PpIX in the bladder in photodynamic therapy.

Photodynamic therapy (PDT) is a new anticancer technique directed at the selective destruction of neoplastic tissue. Aminolevulinic acid (ALA), a precursor in the biosynthesis of home, induces the production of the endogenous photosensitizer protoporphyrin IX (PpIX). In this study the fluorescence distribution of ALA-induced PpIX was investigated in the rat bladder wall by fluorescence microscopy. The fluorescence studies showed that PpIX concentrates in bladder mucosa and that the highest fluorescence levels are achieved after four hours of 300 mg/kg ALA administration. A clear trend in difference between mucosa and muscularis layers was found in all samples taken after 1, 2, 4 and 6 hours of ALA administration. Our results suggest that to get the highest PpIX fluorescence intensity in bladder mucosa it is best to use 300 mg/kg ALA administration. Four hours is the time point when the highest difference in fluorescence between mucosa and muscularis is reached.

Aminolevulinic Acid↗

PubMed1997

Protoporphyrin-IX distribution and photodynamic effect in rat oesophagus after aminolaevulinic acid administration.

BACKGROUND: Photodynamic therapy (PDT) is a method for local and selective tumour destruction achieved by the action of light on a photosensitizing drug. METHODS: We investigated the distribution of 5-amino-laevulinic acid (ALA)-induced protoporphyrin-IX fluorescence in rat oesophagus by fluorescence microscopic examination and then studied the effects of PDT. RESULTS: The highest level of fluorescence was achieved in the mucosa after 4 h of 300 mg/kg ALA administration. A clear difference in fluorescence between mucosa and muscularis was found in all samples except those taken 24 h after ALA administration. PDT with ALA caused destruction of the mucosal and, partly, submucosal layers of the oesophagus without damaging the muscularis layer. CONCLUSIONS: According to our results with microscopic fluorescence kinetics and the preliminary results of PDT, selective destruction of the superficial layer of the rat oesophagus is achieved with PDT after ALA administration.

Aminolevulinic Acid↗