Biomedical subjects

Pekka Saukko

Publications and source records attributed to Pekka Saukko.

13 recordsLinked to original sources

PubMed2006

Tasks of research in forensic medicine - different study types in clinical research and forensic medicine.

In the last years the research output of forensic medicine has sometimes been regarded as insufficient and as of poor quality, especially when parameters as impact factors and external funding were taken into account. However, forensic medicine has different tasks compared to clinical medicine. The main difference between basic subjects, clinical and forensic medicine is not a lack of scientific efficiency in forensic medicine but is a result of the questions asked, the available methods and specific aims. In contrast to natural-scientific research, forensic science has furthermore important intersections with arts and socio-scientific disciplines. Etiologic and pathogenetic research is of only limited relevance in forensic medicine. Thus, forensic medicine is excluded from these research fields, which are mainly supported by external funding. In forensic medicine research mainly means applied research regarding findings, the probative value and reconstruction as well as examination at different points of intersection between medicine and law. Clinical types of research such as controlled randomised, prospective cross-sectional, cohort or case-control studies can only rarely be applied in forensic medicine due to the area specific research fields (e.g. thantatology, violent death, vitality, traffic medicine, analytical toxicology, hemogenetics and stain analysis). The types of studies which are successfully established in forensic medicine are comparison of methods, sensitivity studies, validation of methods, kinetic examinations etc. Tasks of research in forensic medicine and study types, which may be applied will be addressed.

Biomedical Research↗

PubMed2006

Future in forensic medicine as an academic discipline--focussing on research.

Based on a short description of the areas of operation and competence of forensic medicine, current problems, structural deficits of the speciality and possible solutions are discussed. To give future to legal medicine as an academic discipline, research must be given priority over routine casework.

Forensic Sciences↗

PubMed2006

Coronary flow reserve and heart failure in experimental coxsackievirus myocarditis. A transthoracic Doppler echocardiography study.

The objective of this study was to apply transthoracic Doppler echocardiography (TTDE) in mice to study coronary flow reserve (CFR), an index of coronary microvascular function, in mild and severe forms of experimental viral myocarditis. Regarding methodology, BALB/c mice were infected with cardiotropic coxsackieviruses causing either a mild (Nancy strain) or a severe (Woodruff strain) myocarditis. Left ventricular dimensions, fractional shortening, and CFR (ratio of left coronary artery flow velocity during maximal adenosine-induced vasodilatation to rest) were measured by TTDE before infection and again 1 or 2 wk after infection. As a result, the resting flow velocity did not change after infection. In contrast, CFR reduced significantly 1 wk after infection with either virus variant [from 2.5 (SD 0.3) to 1.4 (SD 0.1) in severe and from 2.4 (SD 0.4) to 2.1 (SD 0.3) in mild myocarditis], being significantly lower in the severe than mild myocarditis. CFR remained low in severe myocarditis 2 wk after infection. Fractional shortening decreased to the same levels 1 wk after infection with either virus variant [from 0.54 (SD 0.02) to 0.43 (SD 0.03) in severe and from 0.51 (SD 0.03) to 0.44 (SD 0.02) in mild myocarditis, P < 0.05]. However, 2 wk after infection, mice with severe myocarditis had enlarged left ventricles and lower fractional shortening [0.31 (SD 0.03)] than mice with mild myocarditis [0.47 (SD 0.02), P < 0.01]. In conclusion, CFR measured with TTDE is reduced in coxsackievirus myocarditis in mice. Low CFR is associated with progressive heart failure, indicating that dysfunction of coronary microcirculation is a determinant of poor outcome in viral myocarditis.

Animals↗

PubMed2006

Cystatin B as an intracellular modulator of bone resorption.

Degradation of organic bone matrix requires proteinase activity. Cathepsin K is a major osteoclast proteinase needed for bone resorption, although osteoclasts also express a variety of other cysteine- and matrix metalloproteinases that are involved in bone remodellation. Cystatin B, an intracellular cysteine proteinase inhibitor, exhibits a lysosomal distribution preferentially in osteoclasts but it's role in osteoclast physiology has remained unknown. The current paper describes a novel regulatory function for cystatin B in bone-resorbing osteoclasts in vitro. Rat osteoclasts were cultured on bovine bone and spleen-derived cystatin B was added to the cultures. Nuclear morphology was evaluated and the number of actively resorbing osteoclasts and resorption pits was counted. Intracellular cathepsin K and tartrate-resistant acid phosphatase (TRACP) activities were monitored using fluorescent enzyme substrates and immunohistology was used to evaluate distribution of cystatin B in rat metaphyseal bone. Microscopical evaluation showed that cystatin B inactivated osteoclasts, thus resulting in impaired bone resorption. Cathepsin K and TRACP positive vesicles disappeared dose-dependently from the cystatin B-treated osteoclasts, indicating a decreased intracellular trafficking of bone degradation products. At the same time, cystatin B protected osteoclasts from experimentally induced apoptosis. These data show for the first time that, in addition to regulating cysteine proteinase activity and promoting cell survival in the nervous system, cystatin B inhibits bone resorption by down-regulating intracellular cathepsin K activity despite increased osteoclast survival.

Animals↗

PubMed2005

Long-term evaluation of porous poly(epsilon-caprolactone-co-L-lactide) as a bone-filling material.

Porous poly(epsilon-caprolactone-co-L-lactide) (P(CL-co-LA, wt % ca. 5/95) sponges were prepared, coated biomimetically with CaP/apatite, and implanted with noncoated control sponges into rat femur cortical defects and dorsal subcutaneous space. The implants were inspected histologically at 2, 4, and 33 weeks after the operation. All implants were filled with fibrovascular tissue within 4 weeks. The femur implants were partially ossified with compact bone, which in the CaP-coated sponges was less mature and more fragmented. Approximately equal amounts of bone were observed in both types of implants. The polymer induced a mild inflammatory reaction with foreign body giant cells but no accumulation of fluid. Degradation of the polymer was slow; most of it was found intact at 33 weeks in histological samples. Nondegraded polymer seems to prevent complete ossification. Cultured osteoblasts proliferated well on apatite-coated material, whereas only a few cells were seen on noncoated material. Thus CaP/apatite coating helped the attachment of osteoblasts in cell cultures but did not offer any advantage in bone formation over noncoated material in vivo. We conclude that a shorter degradation time of P(CL-co-LA) is needed to create an optimal implant. Furthermore, in vivo experiments seem to be necessary for the estimation of osteopromotive properties of a biomaterial.

Absorbable Implants↗

PubMed2005

Cytomegalovirus infection of the heart is common in patients with fatal myocarditis.

BACKGROUND: Although enteroviruses and adenoviruses are considered to be the leading causes of the usually mild clinical myocarditis, little is known about the etiology of severe or fatal myocarditis. METHODS: We collected all available clinical records and myocardial autopsy samples for patients who had myocarditis recorded as the underlying cause of death in Finland during the period of 1970-1998. Findings for all available patients (20 men and 20 women; median age, 49 years) with myocarditis that fulfilled the Dallas criteria and who had sufficient data were included in the study. Twelve subjects who had died accidentally served as control subjects. Polymerase chain reaction (PCR) and in situ hybridization assays were used for detection of viral genomes (adenovirus, cytomegalovirus, enterovirus, human herpesvirus 6, influenza A and B viruses, parvovirus B19, and rhinovirus) in heart samples. RESULTS: Viral nucleic acids were found in the hearts of 17 patients (43%), including cytomegalovirus (15 patients), parvovirus B19 (4 patients), enterovirus (1 patient), and human herpesvirus 6 (1 patient). In 4 patients, cytomegalovirus DNA was found in addition to parvovirus B19 or enterovirus genomes. No adenoviruses, rhinoviruses, or influenza viruses were detected in this study of fatal myocarditis. In 67% of the patients for whom PCR was positive for cytomegalovirus, in situ hybridization revealed viral DNA in cardiomyocytes. Only 1 of these patients was immunocompromised. In the control group, only human herpesvirus 6 (1 subject) and parvovirus B19 (1 subject) DNA were detected. CONCLUSIONS: In this population-based study, cytomegalovirus was found to be the most common specific finding in immunocompetent patients with fatal myocarditis. This may have important clinical implications for the treatment of severe acute myocarditis.

Adolescent↗

PubMed2005

Diagnosis and presentation of fatal myocarditis.

The clinical presentation of myocarditis is highly variable, and histopathology is thus considered to be the cornerstone of diagnosis. We studied how accurately myocarditis was diagnosed in a series of routine autopsies and how fatal myocarditis presents clinically. All death certificates with myocarditis recorded as the underlying cause of death in Finland in 1970 to 1998 were collected retrospectively (N = 639). All cases with cardiac autopsy samples and clinical data available (n = 142; median age, 51 years) were included in this study. The cardiac samples were reexamined for the presence of myocarditis by 3 experienced independent pathologists using the Dallas criteria. The clinical data were evaluated for the presenting signs and symptoms of myocarditis. Histopathologic reanalysis showed that only 32% of the 142 subjects met the Dallas criteria for myocarditis (75% of pediatric and 28% of adult patients, P = .001). Clinicians had suspected myocarditis in only one third of the hospitalized Dallas-positive patients. Dallas-positive patients presented more often with features of myocardial infarction (26% versus 9%, P = .026) or heart failure (35% versus 10%, P = .001) than Dallas-negative subjects. The signs and symptoms of infectious disease were also more common in Dallas-positive patients (61% versus 23%, P < .001). In contrast, Dallas-negative subjects died suddenly or were found dead more frequently (68% versus 39%, P = .004). The most evident cause of death in the Dallas-negative subjects was ischemic heart disease (n = 78, 55% of all cases). Our study provides evidence that myocarditis is overdiagnosed on routine autopsies, particularly in patients who have died suddenly or are found dead. Fatal myocarditis appears to present equally often as heart failure, sudden death, or mimicking myocardial infarction.

Adolescent↗

PubMed2005

Loss of lysosomal association of cystatin B proteins representing progressive myoclonus epilepsy, EPM1, mutations.

Loss-of-function mutations in the cystatin B (CSTB), a cysteine protease inhibitor, gene underlie progressive myoclonus epilepsy of Unverricht-Lundborg type (EPM1), characterized by myoclonic and tonic-clonic seizures, ataxia and a progressive course. A minisatellite repeat expansion in the promoter region of the CSTB gene is the most common mutation in EPM1 patients and leads to reduced mRNA levels. Seven other mutations altering the structure of CSTB, or predicting altered splicing, have been described. Using a novel monoclonal CSTB antibody and organelle-specific markers in human primary myoblasts, we show here that endogenous CSTB localizes not only to the nucleus and cytoplasm but also associates with lysosomes. Upon differentiation to myotubes, CSTB becomes excluded from the nucleus and lysosomes, suggesting that the subcellular distribution of CSTB is dependent on the differentiation status of the cell. Four patient mutations altering the CSTB polypeptide were transiently expressed in BHK-21 cells. The p.Lys73fsX2-truncated mutant protein shows diffuse cytoplasmic and nuclear distribution, whereas p.Arg68X is rapidly degraded. Two missense mutations, the previously described p.Gly4Arg affecting the highly conserved glycine, critical for cathepsin binding, and a novel mutation, p.Gln71Pro, fail to associate with lysosomes. These data imply an important lysosome-associated physiological function for CSTB and suggest that loss of this association contributes to the molecular pathogenesis of EPM1.

Animals↗

PubMed2004

Neuropathological examination in forensic context.

Different diseases of and trauma to the central nervous system (CNS), as well as their consequences are common causes of death and therefore it is important to examine the CNS appropriately in forensic autopsy, bearing in mind that the site of the disease is often as crucial as its nature. The CNS is a complex organ and its examination requires special methods and knowledge and often consultation with a neuropathologist. The prerequisite for the proper examination is correct handling and processing of the CNS. Because of its soft consistency fixation of the CNS in toto before detailed macroscopic analysis is recommended but guidance for an expedited limited examination is also given. The key features to which attention should be paid during the removal and later macroscopic examination of the CNS are described. Processing CNS for microscopy also requires special techniques and in addition to the routine stains both special histological and selected immunohistochemical stainings are often needed to reach the correct diagnosis.

Antibodies↗

PubMed2004

Apoptotic cardiomyocyte death in fatal myocarditis.

Acute myocarditis is often a self-limited process with a good outcome. Experimental animal studies have found that cardiomyocyte apoptosis occurs in severe forms of myocarditis. We studied whether cardiomyocyte apoptosis plays a role in the development of fatal acute human myocarditis. Myocardial autopsy samples from subjects who died of acute myocarditis in Finland between 1970 and 1998 were studied. Thirty-three of these cases(16 men and 17 women; 45 +/- 6 years old) were randomly selected for this study. All cases fulfilled the histopathologic Dallas criteria for myocarditis. Eight subjects who had died accidentally served as controls. Apoptotic DNA fragmentation (terminal transferase-mediated DNA nick end labeling) and activation of caspase-3 (immunohistochemistry) were detected. The mode of death was determined retrospectively from all available clinical data. In fatal myocarditis, large amounts of cardiomyocytes showed apoptotic DNA fragmentation or contained active caspase-3 (2.0 +/- 0.3% and 2.8 +/- 0.4%, respectively). In the controls, few apoptotic cardiomyocytes were found (0.008 +/- 0.003% by terminal transferase-mediated DNA nick end labeling and 0.009 +/- 0.003% by detection of active caspase-3, p <0.001 vs myocarditis). The amount of apoptosis did not correlate with the age or gender of the cases, recognized viral etiology, histologic features, or duration of disease. However, more apoptotic cardiomyocytes were detected in the subjects who had myocarditis and had died of heart failure (n = 18) than in those who had myocarditis and died suddenly of cardiac arrest (n = 15; 2.6 +/- 0.4% vs 1.1 +/- 0.2%, p <0.001). In conclusion, cardiomyocyte apoptosis is a common mechanism of myocardial damage in severe acute human myocarditis. Moreover, higher rates of cardiomyocyte apoptosis are associated with the development of fatal heart failure in acute myocarditis.

Analysis of Variance↗

PubMed2004

Screening of some anti-androgenic endocrine disruptors using a recombinant cell-based in vitro bioassay.

The present work describes the development and optimization of a cell-based androgen reporter assay using the Chinese hamster ovarian cell line (CHO K1) in the 96-well format. The recent reports on increasing exposure of humans and wild-life to environmental endocrine disrupting chemicals (ED) prompt the need for high throughput screening systems for such compounds in environmental and biological samples. To this end, CHO cells were cotransfected with plasmids encoding mouse mammary tumour virus-neomycin-luciferase and human androgen receptor (hAR), and a stable cell line was established. After selection with neomycin, a highly active clone was obtained which stably expressed both the hAR and the androgen-responsive luciferase reporter. Stimulation of the cells with androgens for 24 h resulted in about 15-fold stimulation of luciferase activity, with the minimum effective dose of testosterone being 0.1 nmol/l. Potent steroidal and non-steroidal anti-androgens, such as hydroxyflutamide and cyproterone acetate, significantly inhibited the androgen-induced transactivation. Non-androgenic steroids like estradiol, progesterone, dexamethasone and cortisol showed weak activity at high concentrations. RT-PCR and western blot confirmed proper transcription and translation as well as stable expression of the AR gene in the cells. About 60 different chemicals (mostly pesticides or their metabolites, and common industrial chemicals) were screened with the cell line for their ability to stimulate luciferase activity or inhibit that evoked by 0.1 nmol/l R1881, used as a positive androgenic control. About 10 highly potent anti-androgenic chemicals were identified. The most potent anti-androgenic compounds identified in our assay included bisphenol A, alpha-hexachlorocyclohexane, vinclozolin and 4,4-DDE. These compounds had alone either no effect or were weak agonists (with cytotoxic effects at very high concentrations), but none showed any significant agonistic activity. In conclusion, we demonstrate that the bioassay based on this cell line provides a reliable test for detecting androgenic and anti-androgenic compounds. The 96-well plate format makes the assay suitable for high throughput screening.

Androgen Antagonists↗

PubMed2003

Brominated flame retardants and phenolic endocrine disrupters in Finnish human adipose tissue.

Brominated flame retardants and phenolic compounds, of which several have been shown to exhibit endocrine disrupting effects, were screened in extracts of Finnish human adipose tissue samples. The samples were collected during autopsy from 39 subjects, of which 23 were males and 16 females. The samples were homogenised and extracted, and then cleaned-up by preparative gel permeation chromatography. The phenolic compounds were determined in silylated extracts. A total of 21 individual compounds were analysed in the extracts by gas chromatography-mass spectrometry (HRGC-LRMS) in the selected ion monitoring mode. The most commonly occurring compounds were 4-octylphenol diethoxylate, 4,4'-dihydroxybiphenyl, and 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), but also some other alkylphenols, pentabromophenol, and 2,2',4,4',5-penta- and 2,2',4,4',5,5'-hexabromodiphenyl ether could be detected in 1-6 samples. The concentrations were ranging from trace amounts to 71 ng/g of lipid weight. The mean concentration of BDE-47 was 1.20 ng/g lipids, however, in 15 of the samples the concentration was below the detection limit. Compared to other European studies the average concentration of BDE-47 obtained in this study is at the lower end of the reported concentrations.

Adipose Tissue↗

PubMed2002

Reduced cystatin B activity correlates with enhanced cathepsin activity in progressive myoclonus epilepsy.

BACKGROUND: Loss-of-function mutations in the gene encoding cystatin B (CSTB) underlie an inherited neurodegenerative disorder, progressive myoclonus epilepsy of Unverricht-Lundborg type (EPM1). CSTB is an inhibitor of several papain-family cysteine proteases, the lysosomal cathepsins. Its physiological function and the molecular pathways leading to the clinical EPM1 phenotype are unknown. AIM: To elucidate the role of CSTB and different cathepsins in pathogenesis of EPM1. METHOD: We determined the total papain inhibitory (cystatin) and papain-like (cathepsin) activity as well as specific activities of cathepsins B, H, L and S in lymphoblastoid cells of EPM1 patients, carriers and controls. RESULTS: In EPM1 patients, who express reduced levels of CSTB mRNA, the papain inhibitory activity was significantly decreased or absent. This reduction was correlated with significant increase in general cathepsin activity. The increase in cathepsin B, L and S activities was highly significant, whereas the increase in cathepsin H activity was not. CONCLUSIONS: This is the first demonstration of cysteine protease activity being regulated by CSTB activity in a biological context. The effects of decreased CSTB activity in EPM1 pathogenesis may, at least in part, be mediated by cathepsins through increased activity of cathepsins S and L.

Apoptosis↗