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Matti Kontkanen

Publications and source records attributed to Matti Kontkanen.

8 recordsLinked to original sources
PubMed2007

Asymmetric dimethylarginine is not elevated in exfoliation syndrome but symmetric dimethylarginine is related to exfoliative glaucoma.

BACKGROUND: Hyperhomocysteinemia (HH), oxidative stress and endothelial dysfunction are all implicated as possible pathogenetic factors in exfoliation syndrome (XFS) and exfoliative glaucoma (XFG). Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of endothelial nitric oxide and plasma level of ADMA is often elevated in HH. Thus the present study was undertaken to study plasma levels of ADMA with concomitant measurement of symmetric dimethylarginine (SDMA) and L-arginine (L-Arg) in XFS and XFG. METHODS: This cross-sectional, prospective study involved 36 XFS patients, 11 of them having XFG, and 36 age- and gender-matched controls. Fasting plasma ADMA, SDMA and L-Arg levels of participants were determined. A special view was created how plasma L-Arg, ADMA and SDMA correlate to plasma homocysteine (P-Hcy). In addition, the influence of P-Hey values derived from our previous study on the above mentioned parameters were evaluated by cut-off values of P-Hcy, 12 micromol/l for women and 14.5 micromol/l for men. RESULTS The mean plasma ADMA, SDMA and L-Arg levels were 0.41, 0.49 and 62.9 micromol/l in the XFS/XFG group, and 0.41, 0.44 and 69.7 micromol/l in the control group, respectively. As all parameters within the XFS and control group were compared, no statistical significance was stated. On the other hand, a positive correlation was observed between plasma SDMA and P-Hcy in XFGs (P = 0.002), and additionally, also a statistically significant difference was in plasma SDMA between the two groups sorted by cut-off levels of P-Hcy 0.49 +/- 0.15 vs. 0.36 +/- 0.04 micromol/l, above and below cut-off levels, respectively (P = 0.001), but not between ADMA in a respective assay. The mean values of L-Arg were 64.6 +/- 17.2 vs. 74.8 +/- 13.3 microg/l, respectively (P = 0.031). In the XFS subgroup, on the contrary, there was no positive correlation between P-Hcy and plasma SDMA. CONCLUSIONS: A positive correlation of plasma SDMA in respect to P-Hcy in XFGs and increase of SDMA in mild or intermediate hyperhomocysteinemia may indicate SDMA as a marker of developing XFG in hyperhomocysteinemic

Aged↗
PubMed2005

Geldanamycin increases 4-hydroxynonenal (HNE)-induced cell death in human retinal pigment epithelial cells.

Development of age-related macular degeneration (AMD) is associated with functional abnormalities and cell death in retinal pigment epithelial (RPE) cells attributable to oxidative stress. To minimize the adverse effects of oxidative stress, cells activate their defence systems, e.g., via increased expression of heat shock protein (Hsp), activation of stress sensitive AP-1 and NF-kappaB transcription factors. In this study, we examined the accumulation of Hsp70 protein, activation of AP-1 and NF-kappaB transcription factors in human ARPE-19 cells subjected to a 4-hydroxynonenal (HNE)-induced oxidative stress. In addition, the influence of Hsp90 inhibitor geldanamycin (GA) was studied in HNE-treated cells. Mitochondrial metabolic activity and apoptosis were determined to evaluate cell death in the ARPE-19 cells. The ARPE-19 cells showed increased accumulation of Hsp70 protein before of the cytotoxic hallmarks appearing in response to HNE. In contrast, increased DNA-binding activities of AP-1 or NF-kappaB transcription factors were not seen under HNE insults. Interestingly, GA significantly increased cell death in the HNE-treated cells, which was involved in caspase-3 independent apoptosis. This study reveals that the Hsps have an important role in the cytoprotection of RPE cells subjected to HNE-derived oxidative stress.

Aldehydes↗
PubMed2005

[Adult cataract].

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PubMed2004

Plasma and aqueous humour levels of homocysteine in exfoliation syndrome.

BACKGROUND: Recent studies have suggested that the relationship between elevated plasma homocysteine (Hcy) and increased risk of vascular disease holds also for certain diseases of the eye with vascular aetiology. Elevated plasma Hcy levels have been noted among patients with exfoliation syndrome (XFS). The purpose of this study was to establish whether subjects with XFS have higher plasma and aqueous humour Hcy levels values than non-XFS subjects, particularly in relation to vitamin B status. METHODS: Using a cross-sectional study design, 36 subjects with XFS and 36 non-XFS subjects with intraocular pressure (IOP) lower than 23 mmHg, matched by age and gender, were first selected. The participant exclusion criteria included parameters known to alter Hcy metabolism. In the XFS group, 11 subjects had a concurrent diagnosis of exfoliative glaucoma (XFG). Fasting plasma and aqueous humour Hcy samples were collected, along with erythrocyte folate (E-Fol) and serum vitamin B6 and B12 samples. The Hcy samples were analysed using a fluorescence polarization immunoassay method. RESULTS: Plasma Hcy level was significantly higher (P=0.020, after Bonferroni correction for multiple testing) in the XFS group than in the controls. The Hcy concentrations in the aqueous humour did not differ statistically between the two groups. Plasma and aqueous humour Hcy concentrations were not statistically significantly correlated within the groups of exfoliation-positive and -negative subjects. E-Fol, and serum vitamin B6 and B 12 levels did not differ statistically between the XFS group and the control group. CONCLUSIONS: The finding that subjects with XFS are more prone to elevated plasma Hcy emphasizes exfoliation as a clinical sign and a marker of thromboembolic vasculopathies induced by hyperhomocysteinaemia.

Aged↗
PubMed2004

Simultaneous bilateral cataract surgery: a retrospective survey.

PURPOSE: To evaluate patient satisfaction and functional visual outcome, safety, and visual and refractive outcomes of simultaneous bilateral cataract surgery (SBCS). SETTING: North Karelia Central Hospital, Joensuu, Finland. METHODS: A retrospective external review of 200 patients drawn randomly from 637 patients who underwent SBCS at the North Karelia Central Hospital in 2001 was performed. Of the 200 eligible patients, 141 who returned a completed questionnaire on patient satisfaction and functional visual outcome of SBCS were enrolled. Postoperative refraction and best corrected visual acuity (BCVA) were available in 148 eyes of 74 patients. RESULTS: The surgery was carried out under topical anesthesia, and 98% were outpatient surgeries. No serious intraoperative or postoperative complications occurred. Of the 141 patients, 96% (95% confidence interval [CI]: 91-98) experienced SBCS as positive or quite positive, 89% (95% CI: 83-94) felt safe to go home after the surgery, and 91% (95% CI: 85-95) would recommend SBCS to their relatives or friends. The mean visual functioning index (VF-7 score) was 87.3 (median 95). Postoperative BCVA was 20/40 or better in 84% (95% CI: 77-89) and 20/25 or better in 66% (95% CI: 57-73) of the 148 eyes examined. The postoperative refraction was +/-0.75 diopter (D) of the target value in 78% (95% CI: 71-85) and +/-1.5 D in 95% (95% CI: 91-98), and the mean anisometropia was 0.26 D (SD 0.6 D, range 0-1.65). CONCLUSION: This study provides evidence that SBCS by experienced surgeons is likely to be a safe and efficient procedure and is positively received by patients.

Adult↗