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Biomedical subjects

Kimmo Mattila

Publications and source records attributed to Kimmo Mattila.

18 recordsLinked to original sources
PubMed2006

Distal tears of the hamstring muscles: review of the literature and our results of surgical treatment.

BACKGROUND: Hamstring strains are among the most frequent injuries in sports, especially in events requiring sprinting and running. Distal tears of the hamstring muscles requiring surgical treatment are scarcely reported in the literature. OBJECTIVE: To evaluate the results of surgical treatment for distal hamstring tears. DESIGN: A case series of 18 operatively treated distal hamstring muscle tears combined with a review of previously published cases in the English literature. Retrospective study; level of evidence 4. SETTING: Mehiläinen Sports Trauma Research Center, Mehiläinen Hospital and Sports Clinic, Turku, Finland. PATIENTS: Between 1992 and 2005, a total of 18 athletes with a distal hamstring tear were operated at our centre. MAIN OUTCOME MEASUREMENTS: At follow-up, the patients were asked about possible symptoms (pain, weakness, stiffness) and their return to the pre-injury level of sport. RESULTS: The final results were rated excellent in 13 cases, good in 1 case, fair in 3 cases and poor in 1 case. 14 of the 18 patients were able to return to their former level of sport after an average of 4 months (range 2-6 months). CONCLUSIONS: Surgical treatment seems to be beneficial in distal hamstring tears in selected cases.

Adolescent↗
PubMed2006

Clarithromycin reduces recurrent cardiovascular events in subjects without periodontitis.

Inflammation leading to acute coronary syndrome may be triggered by bacteria causing periodontal infection. We investigated if recurrence of cardiovascular events in unstable coronary patients are associated with periodontitis or microbiological/serological markers of it. Periodontitis-related parameters of 141 patients with acute non-Q-wave infarction or unstable angina pectoris, who participated in a double-blind, placebo-controlled study with clarithromycin for 3 months, were adjusted to the occurrence of a recurrent cardiovascular event during a follow-up period (average 519 days). In the age group under 65 years the patients with periodontitis had a univariate odds ratios (OR) 95% confidence intervals (95% CI) of 5.0 (1.02-24.55) for a recurrent cardiovascular event in comparison with patients without periodontitis. Dental status correlated positively with serum lipopolysaccharide concentrations and combined IgG antibody response to Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis. The end point frequency did not differ between clarithromycin and placebo groups in bacterium-positive, seropositive, or periodontitis patients. Fewer end points in clarithromycin group were seen in bacterium-negative, seronegative, edentulous, and non-periodontitis patients. Periodontitis and edentulousness are associated with recurrent cardiovascular events, especially in younger patients. Long-term clarithromycin therapy seems to be beneficial in prevention of recurrent cardiovascular events in non-periodontitis but not in periodontitis patients.

Adult↗
PubMed2006

Territorial waters of the Baltic Sea as a source of infections caused by Vibrio cholerae non-O1, non-O139: report of 3 hospitalized cases.

A fatal infection with temporal relation to 2 other febrile infections caused by Vibrio cholerae non-O1, non-O139 (NCV) occurred in Finland in 2003. All infections were associated with contact with seawater. The patient who died had also eaten home-salted whitefish, tested positive for NCV, preceding his symptoms. All patients had compromising factors, and all strains were distinguishable by pulsed-field gel electrophoresis and negative for the ctx gene. These 3 cases illustrate that, despite being uncommon in Finland, NCVs can cause clinically significant and even fatal infections.

Aged↗
PubMed2006

Posterior malleolar fracture is often associated with spiral tibial diaphyseal fracture: a retrospective study.

BACKGROUND: It is known that posterior malleolar fracture is often associated with tibial diaphyseal fractures. However, in literature there are very few studies on tibial shaft fractures with respect to posterior malleolus fragment. We hypothesized that the incidence of posterior malleolar fracture is higher than in previous studies. METHODS: A total of 74 closed tibial shaft fractures were treated with intramedullary nailing in Turku University Central Hospital between January 1994 and December 1998. There were 55 men and 19 women, with a mean age of 39 years (range, 16 to 58 years). Two cases were excluded and 72 tibial shaft fractures were analyzed retrospectively. RESULTS: Posterior malleolar fracture was observed in 18 cases (25.0%). Only 10 were observed preoperatively in plain films, seven were detected postoperatively and one was not detected at all during the treatment. Retrospectively, all 18 posterior malleolar fractures were detectable in preoperative plain films. CONCLUSION: A fracture of the posterior malleolus was involved in every fourth tibial diaphyseal fracture. The fractures of the posterior malleolus were always detected in preoperative plain films and should be suspected, especially in cases of low-energy spiral distal tibial diaphyseal fractures. We recommend additional plain films to be taken at the ankle region to better visualize these fractures.

Adolescent↗
PubMed2006

Association between blood pressure and survival over 9 years in a general population aged 85 and older.

OBJECTIVES: To investigate the association between blood pressure and mortality in people aged 85 and older. DESIGN: Population-based prospective study with 9-year follow-up. SETTING: Department of Neuroscience and Neurology and Department of Public Health and General Practice, University of Kuopio, and Department of Clinical Neurosciences, Helsinki University Hospital. PARTICIPANTS: Of all 601 people living in the city of Vantaa born before April 1, 1906, whether living at home or in institutions and alive on April 1, 1991, 521 were clinically examined and underwent blood pressure measurement. MEASUREMENTS: Blood pressure was measured using a standardized method in the right arm of the subject after resting for at least 5 minutes. Information on medical history for each participant was verified from a computerized database containing all primary care health records. Death certificates were obtained from the National Register; the collection of death certificates was complete. RESULTS: After adjusting for age, sex, functional status, and coexisting diseases (earlier-diagnosed myocardial infarction, congestive heart failure, dementia, cancer, stroke, or hypertension), low systolic blood pressure (BP) was associated with risk of death. CONCLUSION: Low systolic BP may be partially related to poor general health and poor vitality, but the very old may represent a select group of individuals, and the use of BP-lowering medications needs to be evaluated in this group.

Activities of Daily Living↗
PubMed2005

How does nitrous oxide reductase interact with its electron donors?--A docking study.

Electron transfer reactions are crucial for respiration and denitrification. In this article, we analyze the interaction of nitrous oxide reductase with its electron donors cytochrome c550 and pseudoazurin. Our docking protocol comprises generation of candidate complexes followed by a selection step based on the distance of the donor and acceptor groups in each partner protein. Finally, the structures of the candidate complexes were optimized using a force field calculation, together with a second distance filtering step. The prediction power of this protocol was studied using the crystal structure of the cytochrome c2/photosynthetic reaction center of Rhodobacter sphaeroides as a reference. The results suggest that both cytochrome c550 and pseudoazurin bind at the same hydrophobic surface patch residing near the CuA center of nitrous oxide reductase. The central, well-conserved interaction surface of the donors is hydrophobic, but it is surrounded by numerous lysine side-chains, which interact electrostatically with analogously positioned side-chain carboxylates of the acceptor. The prediction output is an ensemble of energetically similar structures that are rotationally related to each other. While such an ensemble may reflect incomplete prediction power of the docking protocol, it may also manifest a biological situation where there are multiple ways of forming a productive electron transfer complex. Analyses of the predicted structures and the conservation pattern of the amino acid residues suggest the existence of specific electron transfer pathways to and from the CuA center of nitrous oxide reductase.

Azurin↗
PubMed2004

Severe periodontitis enhances macrophage activation via increased serum lipopolysaccharide.

OBJECTIVE: In periodontitis, overgrowth of Gram-negative bacteria and access of lipopolysaccharide (LPS) to circulation may activate macrophages leading to foam cell formation. We investigated whether periodontal treatment affects proatherogenic properties of low-density lipoprotein (LDL) and, thus, macrophage activation. METHODS AND RESULTS: LDL was isolated and characterized before and after treatment from 30 systemically healthy patients with periodontitis. Production of cytokines and LDL cholesteryl ester (LDL-CE) uptake by macrophages (RAW 264.7) was determined. Baseline periodontal variables correlated positively with serum LPS and C-reactive protein concentrations, as well as macrophage cytokine production and LDL-CE uptake. LPS concentration correlated positively with serum concentration of oxidized LDL and cytokine production. Higher cytokine production and LDL-CE uptake were induced by LDL isolated from patients with elevated number of affected teeth before treatment. Patients with serum LPS concentrations above the median (0.87 ng/mL) at baseline had higher serum high-density lipoprotein (HDL) cholesterol (baseline versus after treatment, 1.30+/-0.19 versus 1.48+/-0.28 mmol/L; P=0.002) and HDL/LDL ratio (0.31+/-0.01 versus 0.34+/-0.10; P=0.048), but lower serum LPS concentration (1.70+/-0.49 versus 0.98+/-0.50 ng/mL; P=0.004) and autoantibodies to beta2-glycoprotein I (0.11+/-0.06 versus 0.09+/-0.04 ELISA units; P=0.022) after treatment. CONCLUSIONS: Our results suggest that in systemically healthy patients, the infected/inflamed area in periodontitis is associated with macrophage activation via increased serum LPS concentration.

Animals↗
PubMed2004

Association of apolipoprotein E genotypes, blood pressure, blood lipids and ECG abnormalities in a general population aged 85+.

BACKGROUND: Several studies have linked apolipoprotein E (ApoE) epsilon4 allele with elevated cholesterol and blood pressure levels. Data on the association of APOE genotypes with blood pressure, lipids, atrial fibrillation and ECG abnormalities in individuals aged 85 years and over is sparse. METHODS: This cross sectional study consisted of all residents of the city of Vantaa (N = 601) aged 85 years or over of whom 505 participated in the study. Blood pressure was measured by using mercury sphygmomanometer. 12-Lead ECG, short ambulatory ECG, or both were taken from all study subjects to diagnose atrial fibrillation (AF). Ambulatory ECG was carried out home or in the institute. APOE genotyping was performed using a combination of the polymerase chain reaction (PCR) and solid-phase minisequencing technique. Statistical analysis was made by using Kruskall-Wallis-test (continuous data) and chi2-test (rates and proportions). RESULTS: In these very elderly individuals, APOE 4 allele was significantly associated with elevated cholesterol and low-density lipoprotein (LDL) levels. Blood pressure or cardiac arrhythmias did not differ between APOE genotypes. CONCLUSIONS: These observations suggest that the important role of APOE genotype still influences cardiovascular risk profile even among the very elderly people.

Journal Article↗
PubMed2004

Periodontal infections and atherosclerosis: mere associations?

PURPOSE OF REVIEW: Several lines of evidence from the last few decades suggest that periodontitis is an important risk factor for cardiovascular diseases. In this review we discuss the recent findings on the systemic effects of periodontitis, which may contribute to the pathogenesis of atherosclerosis, with a special emphasis on lipoproteins. RECENT FINDINGS: In addition to the epidemiological studies exploring the direct or indirect relationship between clinical periodontitis and cardiovascular diseases, studies utilizing serology, animal models, cell cultures, and biochemistry of lipoproteins have been published. Local infection in the periodontal pockets triggers a systemic inflammatory response releasing inflammatory mediators and awakens a strong immune response against periodontal pathogens. Elevated systemic antibody levels especially to Porphyromonas gingivalis are associated with an increased risk for atherosclerosis. Periodontitis is also accompanied by proatherogenic changes in both low and high density lipoproteins, which lead to enhanced cholesteryl ester uptake by and reduced cholesterol efflux from macrophages. Vesicles and lipopolysaccharide isolated from P. gingivalis activate macrophages to convert into foam cells. Moreover, animal studies have demonstrated that infection by P. gingivalis enhances progression of atherosclerosis. SUMMARY: Recent studies have clarified the mechanisms by which periodontitis may contribute to the development of atherosclerosis. Serological, animal, and cell culture studies provide evidence that infection by P. gingivalis may promote atherosclerosis. The influence of periodontitis on lipoprotein metabolism has emerged as a new, important factor. Recent studies provide experimental proof that periodontitis may predispose to atherosclerosis.

Arteriosclerosis↗
PubMed2003

Periodontitis decreases the antiatherogenic potency of high density lipoprotein.

Periodontitis, a consequence of persistent bacterial infection and chronic inflammation, has been suggested to predict coronary heart disease (CHD). The aim of this study was to investigate the impact of periodontitis on HDL structure and antiatherogenic function in cholesterol efflux in vitro. HDL was isolated from 30 patients (age 43.6 +/- 6.1 years, mean +/- SD) with periodontitis before and after (3.2 +/- 1.4 months) periodontal treatment. The capacity of HDL for cholesterol efflux from macrophages (RAW 264.7), HDL composition, and key proteins of HDL metabolism were determined. After periodontal treatment, phospholipid transfer protein (PLTP) activity was 6.2% (P<0.05) lower, and serum HDL cholesterol concentration, PLTP mass, and cholesteryl ester transfer protein activity were 10.7% (P<0.001), 7.1% (P=0.078), and 19.4% (P<0.001) higher, respectively. The mean HDL2/HDL3 ratio increased from 2.16 +/- 0.87 to 3.56 +/- 0.48 (P<0.05). HDL total phospholipid mass and sphingomyelin-phosphatidylcholine ratio were 7.4% (P<0.05) and 36.8% (P<0.001) higher, respectively. The HDL-mediated cholesterol efflux tended to be higher after periodontal treatment; interestingly, this increase was significant (P<0.05) among patients whose C-reactive protein decreased (53.7% reduction, P=0.015) and who were positive by PCR for Actinobacillus actinomycetemcomitans. These results suggest that periodontitis causes similar, but milder, changes in HDL metabolism than those that occur during the acute-phase response and that periodontitis may diminish the antiatherogenic potency of HDL, thus increasing the risk for CHD.

C-Reactive Protein↗
PubMed2003

Crystal structure of nitrous oxide reductase from Paracoccus denitrificans at 1.6 A resolution.

N2O is generated by denitrifying bacteria as a product of NO reduction. In denitrification, N2O is metabolized further by the enzyme N2O reductase (N2OR), a multicopper protein which converts N2O into dinitrogen and water. The structure of N2OR remained unknown until the recent elucidation of the structure of the enzyme isolated from Pseudomonas nautica. In the present paper, we report the crystal structure of a blue form of the enzyme that was purified under aerobic conditions from Paracoccus denitrificans. N2OR is a head-to-tail homodimer stabilized by a multitude of interactions including two calcium sites located at the intermonomeric surface. Each monomer is composed of two domains: a C-terminal cupredoxin domain that carries the dinuclear electron entry site known as Cu(A), and an N-terminal seven-bladed beta-propeller domain which hosts the active-site centre Cu(Z). The electrons are transferred from Cu(A) to Cu(Z) across the subunit interface. Cu(Z) is a tetranuclear copper cluster in which the four copper ions (Cu1 to Cu4) are ligated by seven histidine imidazoles, a hydroxyl or water oxygen and a bridging inorganic sulphide. A bound chloride ion near the Cu(Z) active site shares one of the ligand imidazoles of Cu1. This arrangement probably influences the redox potential of Cu1 so that this copper is stabilized in the cupric state. The treatment of N2OR with H2O2 or cyanide causes the disappearance of the optical band at 640 nm, attributed to the Cu(Z) centre. The crystal structure of the enzyme soaked with H2O2 or cyanide suggests that an average of one copper of the Cu(Z) cluster has been lost. The lowest occupancy is observed for Cu3 and Cu4. A docking experiment suggests that N(2)O binds between Cu1 and Cu4 so that the oxygen of N2O replaces the oxygen ligand of Cu4. Certain ligand imidazoles of Cu1 and Cu2, as well as of Cu4, are located at the dimer interface. Particularly those of Cu2 and Cu4 are parts of a bonding network which couples these coppers to the Cu(A) centre in the neighbouring monomer. This structure may provide an efficient electron transfer path for reduction of the bound N2O.

Amino Acid Sequence↗
PubMed2002

Effect of treating periodontitis on C-reactive protein levels: a pilot study.

BACKGROUND: Periodontitis is associated with elevated levels of C-reactive protein and fibrinogen and it may be a coronary heart disease risk factor. We wanted to study if treatment of periodontitis can decrease the levels of these inflammatory markers. METHODS: C-reactive protein and fibrinogen levels were measured in 35 patients (21 M, 14 F, mean age 50 years) with adult periodontitis, before and after treatment. RESULTS: The median baseline C-reactive protein level in the patients was 1.05 mg/l and it decreased to 0.7 mg/l (p = 0.05) after periodontal treatment. Of the 30 patients who could be included in the analyses, 24 patients had a baseline level below 2 mg/l (the 95th percentile limit in Finland); 6 patients had levels higher than this. Elevation of the baseline C-reactive protein level or the magnitude of its decrease were not associated with severe form of periodontitis. The decrease in C-reactive protein levels was at least 50 % in 4/6 of those with elevated baseline levels, as compared with 3/24 of the rest of the patients (p = 0.016). No corresponding effect was observed in fibrinogen levels. CONCLUSIONS: Periodontitis seems to increase C-reactive protein only in some individuals, presumably the ones reacting to it with a systemic inflammatory reaction. Periodontal treatment decreases C-reactive protein levels in these individuals and it may thus decrease their risk of coronary heart disease.

C-Reactive Protein↗
PubMed2002

Effect of 3 months of antimicrobial treatment with clarithromycin in acute non-q-wave coronary syndrome.

BACKGROUND: Coronary artery disease, an inflammatory disease, may be caused by infection. We investigated whether the antibiotic clarithromycin would reduce morbidity and mortality in patients with acute non-Q-wave coronary syndrome. METHODS AND RESULTS: Altogether, 148 patients with acute non-Q-wave infarction or unstable angina were randomly assigned to receive double-blind treatment with either clarithromycin or placebo for 3 months. The primary end point was a composite of death, myocardial infarction, or unstable angina during treatment; the secondary end point was occurrence of any cardiovascular event during the entire follow-up period (average 555 days, range 138 to 924 days). There was a trend toward fewer patients meeting primary end-point criteria in the clarithromycin group than in the placebo group (11 versus 19 patients, respectively; risk ratio 0.54, 95% CI 0.25 to 1.14; P=0.10). By the end of the entire follow-up, 16 patients in the clarithromycin group and 27 in the placebo group had experienced a cardiovascular event (risk ratio 0.49, 95% CI 0.26 to 0.92; P=0.03). CONCLUSIONS: Clarithromycin appears to reduce the risk of ischemic cardiovascular events in patients presenting with acute non-Q-wave infarction or unstable angina. No signs of this effect diminishing were observed during follow-up.

Adolescent↗
PubMed2002

Antigenically diverse reference strains and autologous strains of Actinobacillus actinomycetemcomitans are equally efficient antigens in enzyme-linked immunosorbent assay analysis.

Actinobacillus actinomycetemcomitans is a major pathogen in periodontitis. Data on the clinical relevance of serum immunoglobulin G (IgG) antibody levels against this species are controversial. The aim of the present study was to elucidate how different strains used as antigens in enzyme-linked immunosorbent assay (ELISA) influence the detection of individuals with elevated serum IgG levels against A. actinomycetemcomitans. We hypothesized that the highest antibody levels are targeted to the autologous strains. A total of 19 strains-six antigenically diverse reference strains (serotypes a through e and a nonserotypeable strain) and 13 serotyped autologous strains-were used as whole-cell antigens in ELISA. Serum samples were from 26 untreated adult patients with periodontitis, whose subgingival bacterial samples were either culture positive (n = 13) or culture negative (n = 13) for A. actinomycetemcomitans, and from 10 culture-negative nonperiodontitis subjects. The highest individual (P < 0.05) IgG levels against the reference strains were most commonly against serotypes a and b in patients and against serotype c in nonperiodontitis subjects. The culture-positive patients had the highest (P < 0.05) IgG antibody levels against their autologous strains and against the reference strains of the same serotype. On the contrary, for these patients the levels of antibody against the reference strains of other serotypes were comparable to those of the nonperiodontitis subjects. The results indicated that the serum IgG antibody levels against A. actinomycetemcomitans strongly depend on the strains used as antigens in the ELISA. Elevated serum IgG levels against A. actinomycetemcomitans can be detected equally well using either the autologous strains or a variety of antigenically diverse reference strains as antigens.

Actinobacillus Infections↗