Seppo Rönkkö

University of Eastern Finland, Kuopio, Northern Savo, Finland

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Publications (45)165.06 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The spread of diseases caused by arthropod- borne viruses calls for the development of novel inhibitors that can be used for topical treatment and prevention in endemic areas. Tyrosine sulfate- mediated interactions, and often sulfated polysaccharides, play a crucial role in viral infections and are a potential target for biomimetic nanostructures. We believe cellulose nanocrystals (CNCs) offer a natural nanotechnology- based alternative to other classes of polyanionic inhibitors. By the nature of sulfuric acid hydrolysis, CNCs carry a multivalent display of anionic sulfate groups on their surfaces. We developed multiple approaches for introducing multivalent displays of tyrosine sulfate mimetic ligands on the surface of CNCs. Subsequently, we used CNCs to inhibit fluorescent marker expressing Semliki Forest virus vector (VA7- EGFP) infection in primate cells in vitro. Furthermore, when tyrosine sulfate mimetic CNCs were applied to VA7- EGFP, improved viral inhibition was observed. Additionally, functionalized CNCs did not cause observable toxicity to multiple cell lines. We propose that conjugation of target- specific functionalities to CNC surfaces provides a means to control their antiviral activity and could be potentially employed against a broad range of viruses, including HIV and Herpes simplexes.
    249th ACS National Meeting & Exposition, Denver, CO, United States; 03/2015
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    ABSTRACT: Nanocrystallization is among the foremost drug delivery platform approaches for the commercial development of poorly soluble drugs. There exists an urge to enable a universal shift of the production of the solid nanocrystal formulations from laboratory scale to industrially feasible scale. The success of any formulation development depends on its transferability to large scale manufacture. The objectives of the study were to increase the nanocrystallization batch size and to screen and optimize parameters for industrially feasible itraconazole (ITC) and indomethacin (IND) nanocrystal composition for tablet formulation. Thus, ITC and IND were transformed into nanocrystal suspensions, using an increased batch size of a wet milling process, freeze-dried, and further developed into both direct compression (DC) and granulated (G) tableting masses. According to the investigated powder and tablet properties (true density, flowability, dose uniformity, maximum upper punch force, crushing strength, dissolution, disintegration) and stability testings, it was clear that the amount of the nanocrystals in the solid tablet formulation is critical in order to fully utilize the benefits of the nanocrystals, i.e., fast dissolution, and to produce high-quality tablets. The DC designs of both the model drugs with compositions including 40% of freeze-dried nanocrystalline drug powder outperformed the corresponding granulated tablets in all parameters after the stability surveillance. Copyright © 2015. Published by Elsevier B.V.
    International Journal of Pharmaceutics 03/2015; 485(1-2). DOI:10.1016/j.ijpharm.2015.03.009 · 3.65 Impact Factor
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    ABSTRACT: Two organic radical contrast agents, TEMPO-Glc and TEEPO-Glc, were synthesized and their stabilities and contrast enhancing properties were tested with in vitro NMR and MRI experiments. Owing to the glucose moieties in the prepared compounds, this study presents potential candidates for a tumor targeting fully organic contrast agents for MRI.
    RSC Advances 01/2015; 5(20). DOI:10.1039/C4RA11455H · 3.84 Impact Factor
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    ABSTRACT: Huntington's disease (HD) is an inherited neurodegenerative disorder that primarily affects the medium-size GABAergic neurons of striatum. The R6/2 mouse line is one of the most widely used animal models of HD. Previously the hallmarks of HD-related pathology have been detected in photoreceptors and interneurons of R6/2 mouse retina. Here we aimed to explore the survival of retinal ganglion cells (RGCs) and functional integrity of distinct retinal cell populations in R6/2 mice. The pattern electroretinography (PERG) signal was lost at the age of 8 weeks in R6/2 mice in contrast to the situation in wild-type (WT) littermates. This defect may be attributable to a major reduction in photopic ERG responses in R6/2 mice which was more evident in b- than a-wave amplitudes. At the age of 4 weeks R6/2 mice had predominantly the soluble form of mutant huntingtin protein (mHtt) in the RGC layer cells, whereas the aggregated form of mHtt was found in the majority of those cells from the 12-week-old R6/2 mice and onwards. Retinal astrocytes did not contain mHtt deposits. The total numbers of RGC layer cells, retinal astrocytes as well as optic nerve axons did not differ between 18-week-old R6/2 mice and their WT controls. Our data indicate that mHtt deposition does not cause RGC degeneration or retinal astrocyte loss in R6/2 mice even at a late stage of HD-related pathology. However, due to functional deficits in the rod- and cone-pathways, the R6/2 mice suffer progressive deficits in visual capabilities starting as early as 4 weeks; at 8 weeks there is severe impairment. This should be taken into account in any behavioral testing conducted in R6/2 mice.
    PLoS ONE 12/2014; 9(12):e113317. DOI:10.1371/journal.pone.0113317 · 3.23 Impact Factor
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    ABSTRACT: Successful applications of mesoporous materials often require different surface properties of internal pore walls and external surfaces. The different functional moieties on the different surfaces enable them to fulfill multiple application demands. In this study, we introduce a nanostopper approach to selectively functionalize the different surfaces of porous silicon (PSi). The external surface was functionalized with amine groups to further graft with folic acid (FA) and fluorescein isothiocyanate (FITC) for targeting and imaging, respectively. The pore walls were functionalized with carboxyl groups to obtain a higher loading degree of doxorubicin and realize a pH-triggered drug release. The engineered PSi drug carrier showed specific targeting against cancer cells and improved cell internalization due to the FA functionalization. Moreover, the PSi carrier presented an intracellular drug delivery with pH-triggered functionality. With the selective modification, the loading degree of the drug was increased 4-fold without any compromise in the toxicity of the plain carrier.
    Chemistry of Materials 11/2014; 26:6734-6742. DOI:10.1021/cm503004b · 8.35 Impact Factor
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    ABSTRACT: PurposeChronic conjunctival inflammation, caused by various reasons, for example long-term use of topical drugs and/or their preservatives, affects the outcome of glaucoma surgery by interfering with wound healing. Matrix metalloproteinases (MMPs) remodel extracellular matrix (ECM) and are involved in the wound healing process. This study was designed to evaluate the conjunctival expression of MMPs and their tissue inhibitors (TIMPs) in the normal eye, primary open-angle glaucoma (POAG) and exfoliation glaucoma (ExG) and whether there is an association between staining intensities and deep sclerectomy outcome.Methods Immunohistochemical procedures were performed on conjunctival samples which were obtained from POAG (n = 11) and ExG (n = 14) patients as well as normal (n = 7) subjects. Antibodies against MMPs (MMP-1, -2, -3 and -9) and TIMPs (TIMP-1, -2 and -3) were used.ResultsIn conjunctival stroma, expression levels of MMP-2 (p = 0.047), MMP-3 (p = 0.009), MMP-9 (p < 0.001), TIMP-1 (p = 0.003), TIMP-2 (p < 0.001) and TIMP-3 (p < 0.001) in ExG and MMP-9 (p = 0.008), TIMP-2 (p = 0.02) and TIMP-3 (p = 0.002) in POAG were significantly increased compared to control. We further found correlations between expression of MMP-1 and MMP-3 and the length of pilocarpine treatment.Conclusion The expression of MMPs and TIMPs is increased in the conjunctiva of POAG and ExG patients having a long history of topical antiglaucoma drops. Antiglaucoma agents and/or their preservatives alter the remodelling balance of ECM in conjunctiva of POAG and ExG eyes. The balance between MMPs and TIMPs may play a crucial role in the conjunctival wound healing process and the outcome of glaucoma surgery.
    Acta ophthalmologica 10/2014; 93(2). DOI:10.1111/aos.12550 · 2.84 Impact Factor
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    ABSTRACT: Nanocrystal-based drug delivery systems provide important tools for ocular formulation development, especially when considering poorly soluble drugs. The objective of the study was to formulate ophthalmic, intraocular pressure (IOP) reducing, nanocrystal suspensions from a poorly soluble drug, brinzolamide (BRA), using a rapid wet milling technique, and to investigate their IOP reducing effect in vivo. Different stabilizers for the nanocrystals were screened (hydroxypropyl methylcellulose (HPMC), poloxamer F127 and F68, polysorbate 80) and HPMC was found to be the only successful stabilizer. In order to investigate both the effect of an added absorption enhancer (polysorbate 80) and the impact of the free drug in the nanocrystal suspension, formulations in phosphate buffered saline (PBS) at pH 7.4 and pH 4.5 were prepared. Particle size, polydispersity (PI), solid state (DSC), morphology (SEM) as well as dissolution behavior and the uniformity of the formulations were characterized. There was rapid dissolution of BRA (in PBS pH 7.4) from all the nanocrystal formulations; after one minute 100 percent of the drug was fully dissolved. The effect was significantly pronounced at pH 4.5, where the dissolved fraction of drug was the highest. The cytotoxicity of nanocrystal formulations to human corneal epithelial cell (HCE-T) viability was tested. The effects of the nanocrystal formulations and the commercial product on the cell viability were comparable. The intraocular pressure (IOP) lowering effect was investigated in vivo using a modern rat ocular hypertensive model and elevated IOP reduction was seen in vivo with all the formulations. Notably, the reduction achieved in experimentally elevated IOP was comparable to that obtained with a marketed product. In conclusion, various BRA nanocrystal formulations, which all showed advantageous dissolution and absorption behavior, were successfully formulated.
    International Journal of Pharmaceutics 03/2014; 467(1). DOI:10.1016/j.ijpharm.2014.03.048 · 3.65 Impact Factor
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    ABSTRACT: We present two facile approaches for introducing multivalent displays of tyrosine sulfate mimetic ligands on the surface of cellulose nanocrystals (CNCs) for application as viral inhibitors. We tested the efficacy of cellulose nanocrystals, prepared either from cotton fibers or Whatman filter paper, to inhibit alphavirus infectivity in Vero (B) cells. Cellulose nanocrystals were produced by sulfuric acid hydrolysis leading to nanocrystal surfaces decorated with anionic sulfate groups. When the fluorescent marker expressing Semliki Forest virus vector, VA7-EGFP, was incubated with CNCs, strong inhibition of virus infectivity was achieved, up to 100% and 88% for cotton and Whatman CNCs, respectively. When surface sulfate groups of CNCs were exchanged for tyrosine sulfate mimetic groups (i.e. phenyl sulfonates), improved viral inhibition was attained. Our observations suggest that conjugation of target-specific functionalities to CNC surfaces provides a means to control their antiviral activity. Multivalent CNCs did not cause observable in vitro cytotoxicity to Vero (B) cells or human corneal epithelial (HCE-T) cells, even within the 100% virus-inhibitory concentrations. Based on the similar chemistry of known polyanionic inhibitors, our results suggest the potential application of CNCs as inhibitors of other viruses, such as human immunodeficiency virus (HIV) and Herpes simplex viruses.
    Biomacromolecules 03/2014; 15(4):1534-1542. DOI:10.1021/bm500229d · 5.75 Impact Factor
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    ABSTRACT: Nanoscience holds true promise in enabling efficient formulation development and in vivo delivery of poorly water soluble drugs. The objective of this study was to formulate solid oral nanocrystal delivery systems of itraconazole, and thus enhance the oral bioavailability of the very poorly soluble drug. Nanocrystal suspensions were prepared by a rapid wet milling technique, after which the suspensions were transformed into solid dosage forms by both freeze drying and granulating. Finally, the obtained nanocrystalline powders were capsule-packed as well as compacted to tablets. After in vitro analysis, the formulations (nanocrystal suspension (NPs), freeze dried NPs, granulated NPs) were tested in vivo in a rat model, and compared with commercial itraconazole formulation (Sporanox). Importantly, the results indicated rapid dissolution of the nanocrystalline itraconazole with enhanced bioavailability compared to physical mixture. Drug dissolution in vitro was immediate from NPs and freeze dried powder, and differed significantly from the marketed product (P=0.004 and 0.002, correspondingly) until 30min. Freeze drying was detected to be especially advantageous for the solid dosage forms. It is possible to maintain the original character of the nanocrystals, e.g. rapid dissolution, even after tableting of the nanocrystalline powders. Interestingly, the marketed product out-performed the nanocrystalline formulations in vivo, even though the nanocrystals provided reasonable bioavailability of itraconazole absorption as well. The efficient in vitro dissolution enhancement of the nanocrystalline formulations compared Sporanox® was not realized in in vivo drug absorption.
    Journal of Controlled Release 02/2014; 180(1). DOI:10.1016/j.jconrel.2014.02.016 · 7.71 Impact Factor
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    ABSTRACT: Biomaterials are widely used in ophthalmology, and biodegradable polymers have been evaluated for use in surgery, tissue engineering and targeted drug delivery. We examined the tissue reactions attributable to 3 biodegradable polymers in the rat eye. Inion GTR™ membrane [a blend of 85:15 poly(L-lactide-coglycolide) and 70:30 poly(L-lactide-co-1,3-trimethylene carbonate) copolymers in a molar ratio of 70:30], a 50:50 molar ratio of poly(DL-lactide-coglycolide) (PDLGA 50:50), and a 85:15 molar ratio of poly(DL-lactide-coglycolide) (PDLGA 85:15) were surgically implanted into the subconjuctival space of rat eyes. Biocompatibility was evaluated by following the eyes clinically and with histo- and immunohistochemical techniques. No clinical signs of inflammation were observed around the implants during follow-up. However, immunohistochemical sections revealed increased accumulation of magrophages around PDLGA 85:15 at 2 weeks and of myofibroblasts around GTR membrane material at 1 month. The order of the degradation time of the material was GTR membrane material > PDLGA 85:15 > PDLGA 50:50; Fourier transform infrared microscopy revealed some differences in the degradation behavior of the polymers. Immunohistochemical staining for plasma or cellular fibronectin was observed around all implants. Despite the different decay times and influences on the expression levels of fibronectins, all polymers evoked rather similar tissue reactions during the observation period. This study provides new data on the biocompatibility of biomaterials in rat eyes. Our findings of the tissue decay of the implant and biomaterial-induced tissue reaction may help in the development of better biomaterials for eye surgery with optimal drug delivery properties.
    Ophthalmic Research 07/2011; 46(2):55-65. DOI:10.1159/000322996 · 1.42 Impact Factor
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    ABSTRACT: To investigate the conjunctival inflammatory alterations of patients with primary open-angle glaucoma (POAG) and exfoliation glaucoma (ExG) and correlate the findings with the success of deep sclerectomy (DS) surgery and with the patients' medical history. Altogether 25 POAG and ExG patients of the prospective DS study were divided, based on the diagnosis and success of the operation, into 4 groups, POAG S (success), POAG F (failure), ExG S, and ExG F. Controls were obtained from other ophthalmologic surgery patients who did not have glaucoma, and their conjunctiva was examined to be normal. Inflammatory cell subtypes in the conjunctiva were identified and quantified by using immunohistochemistry and monoclonal antibodies: CD3 (T-lymphocyte marker), CD4 (T-helper lymphocyte marker), CD8 (T-cytotoxic lymphocyte marker), CD20 (pan-B cell marker), CD38 (plasma cell marker), CD45RA (naïve T-cell marker), and CD68 (macrophage marker). Higher numbers of inflammatory cells were found in the conjunctiva of the glaucoma patients on medical treatment compared with the normal conjunctiva of the controls. Moreover, T-lymphocytes, T-helper lymphocytes, T-cytotoxic lymphocytes, B cells, plasma cells, and macrophages were found in significantly higher numbers in patients in whom DS failed during the follow-up period of 2.5 years than those with surgical success. High numbers of cytotoxic and helper T-lymphocytes, plasma cells, and macrophages indicate a chronic inflammatory reaction in the conjunctiva of glaucoma patients. The chronic inflammation is most probably owing to the chronic topical treatment of the patients and seems to be a significant risk factor for DS surgery failure.
    Journal of glaucoma 03/2011; 20(3):172-8. DOI:10.1097/IJG.0b013e3181d9ccb0 · 2.11 Impact Factor
  • T. Vanha-Perttula · S. Rönkkö · R. Lahtinen ·
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    ABSTRACT: Summary The bovine seminal plasma is formed mainly by secretions of epididymis and the glandular epithelia in ampulla, seminal vesicles, prostate and Cowper's glands. The contribution of each organ to the hydrolytic enzyme activities (glycosidases, exopeptidases, phospholipases) of the bull seminal plasma has been analyzed and is reviewed in this paper with special emphasis on the role of the accessory glands. Seminal vesicles seem to have a major role in the secretion of seminal plasma acid α-glucosidase, acid α-mannosidase and β-N-acetylhexosaminidase, aminopeptidase A, dipeptidyl peptidase II and IV and γ-glutamyl transpeptidase as well as Ca2+-dependent and Ca2+-independent phospholipases A2 with distinct substrate specificities, a choline-specific phospholipase C and a Co2+ (Mn2+)-activated sphingomyelinase. The enzyme pattern in the ampulla closely resembled that of the seminal vesicles and obviously contributes to the seminal plasma level of these hydrolases. The bull prostate and Cowper's glands contained a strong Ca2+-dependent phospholipase A2 activity. However, these glands may not contribute to the seminal plasma PLA2 activity. At ejaculation the epididymal spermatozoa are exposed to these enzymes. They may have a specific affinity to sugar, peptide or phospholipid residues at distinct sites of the sperm surface. These enzymes may also participate in the digestion of various other semen components to create a suitable milieu for the emitted spermatozoa.Zusammenfassung Das Seminalplasma des Bullen wird hauptsächlich von den Sekreten des Nebenhodens und der Drüsenepithelien der Ampulle, Bläschendrüse, Prostata und Cowperschen Drüse gebildet. Der Beitrag eines jeden Organs zu den hydrolytischen Enzymaktivitäten (Glycosidasen, Exopeptidasen, Phospholipasen) des Bullen-Seminalplasmas wurde analysiert und in diesem Übersichtsartikel besonders im Hinblick auf die Rolle der akzessorischen Geschlechtsdrüsen dargestellt. Die Bläschendrüsen haben offensichtlich eine größere Bedeutung für das Seminalplasma bei der Sekretion der α-Glucosidase, sauren α-Mannosidase und β-N-Acetylhexosaminidase, Aminopeptidase A, Dipeptidylpeptidase II und IV und der γ-Glutamyltranspeptidase sosie Ca2+-abhängigen und Ca2+-unabhängigen Phospholipasen A2 mit verschiedenen Substratspezifizitäten einer Cholin-spezifischen Phospholipase C und einer Co2+ (Mn2+)-aktivierten Sphingomyelinase. Das Enzymmuster der Ampulle ähnelt dem der Bläschendrüse sehr stark und trägt offensichtlich zum Seminalplasmaspiegel dieser Hydrolasen bei. Die Bullenprostata und Cowpersche Drüse enthalten eine starke Ca2+-abhängige Phospholipase A2-Aktivität. Diese Drüsen scheinen jedoch nichts zur PLA2-Aktivität des Seminalplasmas beizutragen. Bei der Ejakulation werden die Nebenhodenspermien diesen Enzymen ausgesetzt. Sie dürften eine spezifische Affinität für Zucker, Peptide oder Phospholipidreste an be-stimmten Domänen der Spermienoberfläche besitzen. Außerdem könnten diese Enzyme bei der Zerlegung verschiedener anderer Komponenten des Samens beteiligt sein und so ein geeignetes Milieu für die freigesetzten Spermatozoen bilden.
    Andrologia 04/2009; 22(S1):10 - 24. DOI:10.1111/j.1439-0272.1990.tb02067.x · 1.63 Impact Factor
  • S Rönkkö · A Linnala-Kankkunen · A L Tuhkanen ·
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    ABSTRACT: A fraction from bovine seminal vesicle fluid that initiated acrosome reaction of bovine epididymal spermatozoa in vitro in the presence of heparin was prepared by sequential chromatographies on heparin-Sepharose, gel filtration (Superose 12) and reversed phase chromatography (ProRPC). Sequence analysis of the separated fraction showed that it contained the major protein (PDC-109) with 100% homology. This fraction contained also Ca(2+)-dependent phospholipase A2-like activity which hydrolysed phosphatidylethanolamine and phosphatidylcholine with 14C-labelled linoleic (lino-PE, lino-PC) or arachidonic acid (ara-PE, ara-PC) at sn-2 position. This protein was not detected in N-terminal sequence analysis. Lysophosphatidylcholine, lysophosphatidylethanolamine, and p-bromophenacyl bromide (p-BPB) inhibited this lipolytic activity. Sulfoglycolipid (Seminolipid) had inhibitory effect at concentrations above 0.1 mM but activated slightly the enzyme at lower concentrations. Boiling destroyed acrosome initiating activity in the separated fraction.
    Andrologia 03/2009; 26(2):73-8. DOI:10.1111/j.1439-0272.1994.tb00760.x · 1.63 Impact Factor
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    ABSTRACT: New straightforward applications of new biopolymers are needed in glaucoma surgery. The aim of this study was to compare biocompatibility of three biomaterials in rabbit eyes after deep sclerectomy; a collagen implant (AquaFlow) represented the "gold standard". A blend of 85:15 poly(L-lactide-co-glycolide) and 70:30 poly(L-lactide-co-1,3-trimethylene carbonate) copolymers in a molar ratio of 70:30 (Bio-1 = Inion GTR membrane) and poly(DL-lactide-co-glycolide with molar compositions of 50:50 (Bio-2) and 85:15 (Bio-3) were inserted into rabbits eyes. Bio-1, Bio-2 or Bio-3 caused very mild eye irritation or tissue response which was comparable to that of the collagen implant. The biodegradation time of Bio-1, Bio-2, and Bio-3 implants was over one year, 3 months and 6 months, respectively. Implant mapping by Fourier transform infrared (FTIR) microscopy revealed a heterogeneous distribution of degradation products throughout Bio-1, Bio-2, and Bio-3. All implants were surrounded by a very fine tissue capsule which was not visible after total degradation of the implants. The FTIR spectrum of tissue capsule around Bio-1 was almost identical to that around Bio-2 whereas significant differences were observed in the spectrum of the tissue capsule around Bio-3. Despite some differences in tissue response, all tested implants represent biologically acceptable materials for drainage devices in glaucoma surgery.
    Journal of Biomedical Materials Research Part A 03/2009; 88(3):717-24. DOI:10.1002/jbm.a.31932 · 3.37 Impact Factor
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    ABSTRACT: To evaluate the effects of 5-fluorouracil (5-FU) on ocular cells in vitro and the effects of degradable 5-FU-loaded poly(DL-lactide-co-glycolide; PDLGA) 50:50 implant in the rabbit eye in vivo. Cytotoxicity was assessed with a tetrazolium salt WST-1 cell proliferation/viability test and a lactate dehydrogenase (LDH) leakage test in rabbit corneal stromal fibroblasts (SIRCs), bovine corneal endothelial cells (BCECs), human conjunctival epithelial cells (IOBA-NHCs), human retinal pigment epithelial cells (ARPE-19), and human corneal epithelial cells (HCECs). The 5-FU-loaded PDLGA implants were surgically placed in rabbit eyes with a deep sclerectomy technique and the histopathology of the eyes was examined. In vitro, 5-FU affected cell proliferation and survival in a time- and dose-dependent manner. In the WST-1 test, adverse effects in serum-free conditions started from 0.0005 mg/mL 5-FU in SIRCS and HCECs, whereas in other cell types, 0.005 mg/mL 5-FU hindered cell proliferation. In serum-free conditions 72-hour 5 mg/mL 5-FU treatment decreased cell viability to 40% in BCECs and to 10% to 15% in other cell types. 5-FU had no or very minor effects on LDH leakage. In vivo, the 5-FU implant showed no signs of toxicity in cornea and retina, whereas in the conjunctival stroma near the implantation site, some inflammatory cells and a marked subepithelial condensation of stromal connective tissue was observed during the postoperative period of 4 weeks. 5-FU had a broad therapeutic range, and the 5-FU implant showed only minor tissue reactions in conjunctiva at the surgical site. 5-FU is a possible candidate for controlled drug release.
    Investigative ophthalmology & visual science 02/2009; 50(5):2216-23. DOI:10.1167/iovs.08-3016 · 3.40 Impact Factor
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    ABSTRACT: Chronic situations like long-term use of topical medications induces conjunctival inflammation and is also a significant risk factor for failure of filtering surgery. We evaluated conjunctival expression of group IIA secretory PLA(2) (sPLA(2)-IIA), group V secretory PLA(2) (sPLA(2)-V), calcium-independent PLA(2) (iPLA(2)) and cytosolic PLA(2) (cPLA(2)). Samples were obtained from non-glaucomatous patients (control subjects), and patients with either primary open-angle glaucoma (POAG) or exfoliation glaucoma (ExG). All the glaucoma patients had been treated with antiglaucomatous medication, and underwent deep sclerectomy surgery. Antibodies against sPLA(2)-IIA, sPLA(2)-V, iPLA(2) and cPLA(2) were used for immunohistochemical staining of frozen tissue sections. In the human conjunctiva of non-glaucomatous patients, immunostaining of sPLA(2)-IIA, sPLA(2)-V or cPLA(2) was low and positively stained cells were mainly localized in the surface of the epithelium. In contrast, iPLA(2) was found to predominate in human normal conjunctiva and it demonstrated strong labeling throughout the epithelium. The stromal staining of iPLA(2) was weak. Expression of sPLA(2)-IIA was significantly increased in stromal fibers of patients with POAG or ExG. No changes were found in levels of sPLA(2)-V, iPLA(2) or cPLA(2) between the patient groups and controls. These findings demonstrate that sPLA(2)-IIA, sPLA(2)-V, iPLA(2) and cPLA(2) are expressed in the conjunctiva of non-glaucomatous patients. In the epithelium, sPLA(2)-IIA, sPLA(2)-V, and cPLA(2) may participate in protection against risks caused by mechanical wear and tear stress whereas iPLA(2) may regulate remodeling and maintenance of membrane phospholipids. sPLA(2)-IIA may also have the important role in the degradation of bacteria. In conjunctival stroma of POAG and ExG patients, sPLA(2)-IIA may play a role in the development of scar tissue after glaucoma filtration surgery.
    Albrecht von Graæes Archiv für Ophthalmologie 06/2008; 246(5):739-46. DOI:10.1007/s00417-007-0757-4 · 1.91 Impact Factor
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    ABSTRACT: Various lipid nanoparticle formulations were investigated with respect to (trans)dermal drug delivery with special regard to the mechanism of their effects on human and an organotypic cell culture epidermis. Potential alterations of stratum corneum lipid domains were studied using fluorescence assays with labeled liposomes and thermal analysis of isolated stratum corneum. Influences on the permeation of corticosterone were investigated and the occlusive properties of the nanoparticles were determined by measurements of the transepidermal water loss (TEWL). The penetration of a fluorescence dye was visualized by fluorescence microscopy of cross sections of human epidermis after incubation with cubic and solid lipid nanoparticles. Corticosterone permeation was limited when applied in matrix-type lipid nanoparticles (fat emulsion, smectic and solid lipid nanoparticles). An adhesion of solid lipid nanoparticles was clearly observed in thermal analysis as reflected by additional phase transitions probably caused by the nanoparticle matrix lipid. However, as for the other matrix-type nanoparticles, no distinct alterations of the phase transitions of the stratum corneum lipids were observed. Cubic nanoparticles led to the most predominant effect on skin permeation where the surface-active matrix lipid may act as penetration enhancer. An alteration of the stratum corneum lipids' thermal behavior as well as an interaction with fluorescence labeled liposomes was observed. Differences observed in permeation studies and thermal analysis of human and cell culture epidermis indicate that surface lipids, which are not present to the same extent in the cell culture model than in human epidermis, seem to play an important role.
    International Journal of Pharmaceutics 05/2008; 354(1-2):180-95. DOI:10.1016/j.ijpharm.2007.08.028 · 3.65 Impact Factor
  • Tuomo Puustjärvi · Seppo Rönkkö · Markku Teräsvirta ·

    Albrecht von Graæes Archiv für Ophthalmologie 07/2007; 245(6):907-9. DOI:10.1007/s00417-006-0515-z · 1.91 Impact Factor
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    ABSTRACT: In glaucoma, extensive pathological changes occur in the trabecular meshwork (TM) and juxtacanalicular tissue of the chamber angle. Aqueous humor drainage is disturbed due to the accumulation of extracellular matrix (ECM) material in the outflow system. Matrix metalloproteinases (MMPs) remodel ECM material and, thus, they may have a role in regulating outflow facility and intraocular pressure (IOP). This study examined the expression of MMPs and tissue inhibitors of MMPs (TIMPs) in the chamber angle of normal eyes and in primary open-angle glaucoma (POAG) and in exfoliation glaucoma (ExG). TM tissues were isolated from healthy donor eyes for corneal transplantation. Specimens of the inner wall of Schlemm's canal and the juxtacanalicular tissue were collected from patients with POAG or ExG during deep sclerectomy operation. Monoclonal antibodies against MMPs (MMP-1, -2, -3, and -9) and antibodies against TIMPs (TIMP-1, -2, and -3) were used for immunohistochemical staining. Immunoreactivity for MMP-2, TIMP-2, or TIMP-3 was observed in human normal TM and in the inner wall of Schlemm's canal. In general, immunoreactions for all of the tested MMPs were more intense in POAG samples than in ExG samples or in the control group. The only exception was the MMP-2 level, which was the highest in the control group. The staining intensity of MMP-1 or MMP-3 was significantly higher in POAG when compared to ExG. TIMP-1 was significantly increased in POAG compared with ExG and there were no marked differences in the levels of TIMP-2 or TIMP-3 between POAG and ExG. The ratios of MMP-1/TIMP-1 and MMP(1+2+3+9) and TIMP(1+2+3) were significantly higher in samples from POAG compared to those of ExG. Our results reveal an expression imbalance between MMPs and their endogenous tissue inhibitors in tissue samples from patients with POAG and ExG. Differences in immunohistochemical reactions reflect discrete local pathogenic mechanisms involved in POAG and ExG. With respect to the proposed role of MMPs in the remodeling of ECM material, this may point to a weaker reactivity to the accumulation of ECM material in TM in ExG than POAG eyes.
    Albrecht von Graæes Archiv für Ophthalmologie 06/2007; 245(5):697-704. DOI:10.1007/s00417-006-0440-1 · 1.91 Impact Factor
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    ABSTRACT: Phospholipase A2 (PLA2) is a growing family of lipolytic enzymes that play a key role in various biological processes including general lipid metabolism, membrane homeostasis, and in diseases such as atherosclerosis, arthritis, and acute pancreatitis. Oxidative stress as well as inflammation may be associated with glaucoma pathogenesis. Therefore, our aim was to examine the expression of group IIA secretory PLA2 (sPLA2-IIA), group V secretory PLA2 (sPLA2-V), calcium-independent PLA2 (iPLA2), and cytosolic PLA2 (cPLA2) type in the trabecular meshwork (TM) and the canal of Schlemm in normal eyes and in juxtacanalicular tissue samples from patients with primary open angle glaucoma (POAG) or exfoliation glaucoma (ExG). TM tissues were isolated from healthy donor eyes for corneal transplantation. Specimens of inner wall of the Schlemm's canal and the juxtacanalicular tissue were collected during deep sclerectomy from the eyes of patients who had POAG or ExG. Antibodies against PLA2s (sPLA2-IIA, sPLA2-V, iPLA2, and cPLA2) and a standard immunohistochemical procedure were used for the analysis. Quantification of immunoreactions was provided using a Photoshop-based image analysis. Double-staining immunofluorescence of macrophages and sPLA2-IIA was performed by using confocal microscopy. sPLA2-IIA was not present in normal TM. In contrast, sPLA2-IIA levels were significantly higher in glaucoma patients than in controls. Furthermore, sPLA2-IIA expression was much higher in POAG when compared to ExG. iPLA2 was found to predominate in normal human TM, and it demonstrated strong labeling in the uveal and corneoscleral meshwork. The staining of juxtacanalicular meshwork was only moderate in density. In contrast, expression of the enzyme was significantly decreased in glaucoma patients, especially in ExG, when compared to normal controls or to POAG. In addition, strong regional differences were detected in sPLA2-IIA and iPLA2 levels in POAG, whereas immunostaining of these enzymes was much lower and rather uniform throughout ExG sample. In POAG, sPLA2-IIA staining was restricted to certain parts of the trabecular samples where sPLA2-IIA positive macrophages were also present. Immunostaining of sPLA2-V or cPLA2 was low, and no significant changes were found in levels of these enzymes between normal and glaucomatous samples. sPLA2-IIA, an oxidative stress marker in atherosclerosis, is overexpressed especially in POAG. This result supports the hypothesis that oxidative stress may play a significant role in the pathogenesis of POAG. In ExG, a dramatic decrease in the expression level of iPLA2, a housekeeping enzyme in phospholipid remodeling, may indicate imbalance in phospholipid turnover and also inhibition of normal physiological functions in the TM. These findings may contribute to understanding the pathogenesis of POAG and ExG and may be important for the development of novel therapeutic strategies to different glaucomas.
    Molecular vision 02/2007; 13:408-17. · 1.99 Impact Factor

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  • 2011-2015
    • University of Eastern Finland
      • School of Pharmacy
      Kuopio, Northern Savo, Finland
  • 1992-2011
    • University of Kuopio
      • • Department of Ophthalmology
      • • Department of Pharmaceutics
      • • Department of Anatomy
      Kuopio, Northern Savo, Finland
  • 1998-2001
    • Kuopio University Hospital
      • Department of Surgery
      Kuopio, Province of Eastern Finland, Finland