Biomedical subjects

S Räisänen

Publications and source records attributed to S Räisänen.

At least 19 recordsLinked to original sources

PubMed2006

Magnetic resonance imaging and radiographic findings of seal finger.

PURPOSE: To describe the magnetic resonance imaging (MRI) and radiographic findings of five patients with seal finger. MATERIAL AND METHODS: The MR images and radiographs of five patients with seal finger were retrospectively evaluated. MRI was performed on four patients in the subacute phase, and follow-up imaging was done on one of them at 5 months. One patient had MRI only at a later stage 5 years after onset. Radiographs were taken three times in the subacute phase and once at a later stage. One patient had had seal finger in another finger previously. RESULTS: Short-tau inversion-recovery (STIR) sequence showed extensive subcutaneous soft tissue edema in all four patients in the subacute phase and tenosynovitis of the flexion tendons in two cases. Three patients had edema in 2-3 phalanges, and effusion in the distal interphalangeal (DIP) joint was seen in one case. At the later stage, no signal pathology in soft tissues or bones was seen in STIR images. In the subacute phase, radiographs showed digital soft-tissue swelling in three patients, and one patient had a narrowed DIP joint, periarticular osteoporosis, and a periosteal reaction. At the later stage, flexion contracture of the finger was seen. CONCLUSION: In addition to soft-tissue infection, seal finger causes bone marrow edema, tenosynovitis, and effusion in the interphalangeal joints visible as increased signal intensity in STIR images. Radiographs reveal periarticular osteoporosis with loss of cartilage in the subacute phase and flexion contracture at the later stage. MRI (STIR) allows more precise delineation of the inflammatory process compared to radiography.

Adult↗

PubMed2004

Magnetic resonance imaging findings and outcome in severe tick-borne encephalitis. Report of four cases and review of the literature.

PURPOSE: To describe the magnetic resonance imaging (MRI) findings of four patients with proven tick-borne encephalitis (TBE). These are the most northern cases reported from Scandinavia. Experience of turbo fluid-attenuated inversion recovery (FLAIR) and diffusion-weighted imaging (DWI) has not previously been published in this context. MATERIAL AND METHODS: The MRI findings of four consecutive patients with TBE treated in our hospital during the year 2002 were evaluated. MRI was done during the first week of illness, and follow-up scans were available in three cases. RESULTS: In T2-weighted and turbo FLAIR images, thalamic hyperintensity was equally evident in three of the four patients. One of them also showed hyperintensity in the left putamen and the internal capsule and another patient in the peduncles and the hypothalamus. T1-weighted images without contrast were normal in all patients, and leptomeningeal enhancement was detected in only one patient. The two patients who underwent DW images did not show any restricted diffusion. Follow-up MR images showed no atrophy or necrotic foci, and the signal abnormalities disappeared during 16-34 weeks of follow-up. CONCLUSION: T2-weighted and turbo FLAIR sequences proved equally effective in detecting and delineating the thalamic, brainstem, and basal ganglia pathologies. According to our results, mechanisms other than cytotoxic edema contribute to the signal pathology. Radiologists should be familiar with the MR findings of TBE even in non-endemic areas.

Adult↗

PubMed2001

Bacterial coating with immunoglobulins on the palatine tonsils during infectious mononucleosis: immunocytochemical study with gold markers.

Epithelial cells and bacteria were sampled from the tonsillar surfaces of seven patients (six males, one female; median age 16 years, range 10 to 21 years) suffering from acute infectious mononucleosis with concomitant pharyngotonsillitis. By using gold-labelled antiserum to human IgG and secretory IgA (sIgA), micro-organisms on the tonsillar surfaces coated with these immunoglobulins could be identified by tracing the gold particles in the transmission electron microscope. The patients harboured significantly fewer bacteria coated with immunoglobulins than did healthy controls. More bacteria were coated with IgG immunoglobulins than with sIgA. Reduced immunoglobulin-coating of the bacteria on the tonsillar surfaces during infectious mononucleosis can explain their tendency to immense local colonization and proneness to penetrate into the epithelial cells.

Acute Disease↗

PubMed2000

Bacterial penetration into tonsillar surface epithelium during infectious mononucleosis.

Bacterial penetration into epithelial cells, scraped from the palatine tonsils of 14 patients (10 males, four females; median age 16 years) with current infectious mononucleosis and concomitant membranous tonsillitis, was studied using the transmission electron microscopic (TEM) technique. Bacteria were seen to adhere to and penetrate the epithelial cells, some of which were completely filled with bacteria. This finding suggests intracellular proliferation of bacteria. Epstein-Barr virus, the causative agent of infectious mononucleosis, especially when associated with growth of beta-haemolytic streptococci on the palatine tonsils, induces bacterial penetration into tonsillar tissue, that in turn might be a causative mechanism in the development of peritonsillar abscess.

Adolescent↗

PubMed1999

Where are the receptors for Streptococcus pyogenes located on the tonsillar surface epithelium?

Streptococcus pyogenes is the most frequent causative agent of acute pharyngotonsillitis (AT). The first events in the etiopathogenesis of an AT infection caused by these bacterial pathogens are their penetration through the mucus film covering the oropharyngeal mucosa, and their attachment to the surface epithelium. Adherence of S. pyogenes to tonsillar epithelial cells is a precondition for bacterial colonisation, for triggering off cell activation, internalising of bacteria into the epithelial cells and cytokine release from the epithelial cells with subsequent induction of an inflammatory reaction in underlying tissues. Scanning and transmission electron microscopic studies revealed that the surface epithelium of the human palatine tonsils consisted of a weakly keratinized, stratified squamous epithelium built up of pentangular cells where the apical cell surface formed an irregular pattern of microridges. The distance between two adjacent microridges was roughly one-third of the diameter of a S. pyogenes bacterium. By using gold-labelled antiserum to S. pyogenes, we showed that the target region for these pathogens on the epithelial cells during an on-going AT infection was located on the crests of the microridges where bacterial pili made adhesin-receptor contact with the tonsillar surface epithelium.

Adolescent↗

PubMed1999

Intracellular fragmentation of bone resorption products by reactive oxygen species generated by osteoclastic tartrate-resistant acid phosphatase.

Tartrate-resistant acid phosphatase (TRAP) is highly expressed in bone-resorbing osteoclasts and activated macrophages. It has been suggested that a redox-active iron in the binuclear iron center of TRAP could have the capacity to react with hydrogen peroxide to produce highly destructive reactive oxygen species (ROS). Here we show that TRAP can generate ROS in vitro and that cells over-expressing TRAP produce higher amounts of intracellular ROS than their parent cells. We further demonstrate that these ROS can be targeted to destroy collagen and other proteins. In resorbing osteoclasts, TRAP was found in transcytotic vesicles transporting matrix degradation products through the cell, suggesting that TRAP-facilitated fragmentation of endocytosed material takes place in a specific cellular compartment. These results suggest that bone matrix degradation occurs not only extracellularly in the resorption lacunae but also intracellularly in the transcytotic vesicles. We propose that proteins containing redox-active iron could represent a novel mechanism of physiological fragmentation of organic molecules. This mechanism could be important in tissue remodeling and as a defense mechanism of phagocytosing cells.

Acid Phosphatase↗

PubMed1999

SIgA- and IgG-coated Streptococcus pyogenes on the tonsillar surfaces during acute tonsillitis.

Bacterial swabs were collected from the tonsillar surfaces of eight patients with current acute tonsillitis, culture-positive for Streptococcus pyogenes. Using gold-labelled antiserum to S. pyogenes, these micro-organisms could be localized in the samples by transmission electron microscopy. S. pyogenes pathogens were further characterized with gold-labelled antiserum to human IgG and SIgA antibodies. Roughly 90% of the pathogens were found coated with IgG antibodies, irrespective of the duration of the disease, whereas the proportion of SIgA-coated pathogens increased with disease duration. Insufficient IgA coating of pathogens might well be a contributory cause of the induction of tonsillar infection, probably due to inadequate prevention of the attachment of the S. pyogenes bacteria to the tonsillar surface epithelium.

Acute Disease↗

PubMed1998

Initial events in the pathogenesis of acute tonsillitis caused by Streptococcus pyogenes.

Bacterial and epithelial cell samples were obtained, within 24 h of onset of pharyngeal symptoms, from the palatine tonsils of nine patients (four female and five male; age range 10-40 years, median age 23) with acute tonsillitis, culture-positive for Streptococcus pyogenes. The specimens were examined using fluorescein isothiocyanate- (FITC) and gold-labelled antiserum to S. pyogenes and fluorescence, scanning electron and transmission electron microscopy. S. pyogenes could be identified both in the mucous layer covering the tonsils and attached to the surface epithelial cells. Long chains of coccus-shaped bacteria could be seen encroaching on the epithelial cell borders. S. pyogenes can apparently penetrate the mucous barrier, attach to the epithelial cells, spread from cell to cell and possibly penetrate into the outermost layer of the epithelial cells. These events in turn provoke cytokine production and/or complement activation, which induce inflammatory reaction in the tonsillar tissue.

Acute Disease↗

PubMed1998

Immunoglobulin- and complement-coated bacteria in pus from peritonsillar abscesses.

Fifty-five samples of pus were collected from 51 acute, non-perforated, two spontaneously ruptured and two recurrent peritonsillar abscesses (35 males and 18 females; median age 18 years) and analysed regarding (i) aerobic and anaerobic bacteria (standard culturing), (ii) morphology of bacteria and inflammatory cells (direct microscopy of acridine orange-stained material), and (iii) the percentage of bacteria coated with immunoglobulins IgG, secretory IgA (SIgA) and IgM and complement cleavage product C3b (immunofluorescence assay). Seventy-one per cent of the abscesses harboured a mixed bacterial flora of various aerobes and anaerobes. In none of the cases with a single bacterial species (27 per cent) could immunoglobulin- or complement-coated bacteria be found. In abscesses with a mixed flora, 18 per cent harboured IgG-coated, 15 per cent SIgA-coated, five per cent IgM-coated and five per cent C3b-coated bacteria, respectively. All pus samples contained inflammatory cells in abundance but they were mostly deformed and only occasionally could intracellular bacteria be recognized. Insufficient immunoglobulin-coating of bacteria might be an important aetiopathogenic factor in the development of a peritonsillar abscess. Bactericide in the abscesses is accomplished chiefly by protective mechanisms not dependent on antigen recognition by antibodies.

Adolescent↗

PubMed1997

Pharmacokinetics of enrofloxacin in newborn and one-week-old calves.

The pharmacokinetic behaviour of enrofloxacin was compared in four one-day-old and four one-week-old calves in order to find out if there were any age-related differences. Mean volume of distribution (Vd(ss)) and clearance (Cl) were significantly smaller in newborn calves: Vd(ss) was 1.8 and 2.3 L/kg, while clearance was 0.19 and 0.39 L/kg.h in newborn and one-week-old calves, respectively. Mean elimination half-life (t1/2 beta) did not differ significantly in newborn and in one-week-old calves: mean t1/2 beta was 6.6 h and 4.9 h, respectively. Enrofloxacin was metabolized to ciprofloxacin both by newborn and one-week-old calves, but the maximum concentration (Cmax) of ciprofloxacin was lower and the time when maximum concentration was reached (tmax) later in newborn calves. We conclude that the dosage of enrofloxacin should be adjusted according to age when administered to very young calves.

Aging↗

PubMed1997

Selective attachment of beta-haemolytic streptococci group A to oropharyngeal epithelium in health and disease.

Localization and semiquantification of beta-haemolytic streptococci, Group A (GABHS), GABHS attachment and general bacterial attachment to epithelial cells (bacterial number and morphology) were studied during GABHS-positive acute tonsillitis and pharyngitis infections and among healthy GABHS carriers. Samples were collected from various areas of the oropharynx (palatine tonsils, posterior oropharyngeal wall, palatoglossal arch and buccal mucosa). During acute tonsillitis and pharyngitis, GABHS grew in samples obtained from the palatine tonsils and posterior oropharyngeal wall. The ratio of GABHS colonies to other aerobic colonies increased, and GABHS became attached to epithelial cells of both palatine tonsils and posterior oropharyngeal wall. In GABHS carriers, GABHS were found mainly on the palatine tonsils, but these microorganisms were not attached to the epithelium. Overall bacterial attachment to tonsillar and oropharyngeal epithelial cells increased during active tonsillitis and pharyngitis.

Attachment Sites, Microbiological↗

PubMed1997

Immunoglobulin-coated bacteria in effusions obtained during chronic maxillary sinusitis.

Local protection of the maxillary sinuses against bacterial invasion takes both specific and non-specific forms. The present study is intended to evaluate the participation of the specific protective factors, immunoglobulins IgG, secretory IgA, IgM and complement, in protecting the maxillary sinuses during chronic maxillary sinusitis (CMS). We collected 47 sinus effusion samples from 37 patients (17 male, 20 female) with current CMS of at least 3 months' duration. Patients' ages ranged from 3 to 80 years. The effusion material was subjected to qualitative and quantitative bacteriological analyses, while bacterial coating with IgG, SIgA, IgM and C3b was determined using an immunofluorescence technique. Detectable bacteria were harboured by 55% of the samples, the most common species being Moraxella catarrhalis, Streptococcus pneumoniae and Staphylococcus aureus. The bacterial counts ranged from 0 to 10(9) per ml effusion. Half of the samples hosting detectable bacteria showed microorganisms coated with protective immunoglobulins. Antibacterial factors had completely eradicated the microorganisms in 45% of the CMS cases and coated the organisms with specific immunoglobulins in a further 28%.

Adolescent↗

PubMed1997

Identification of Streptococcus pyogenes on tonsillar epithelium during infection.

Epithelial cells were swabbed from the tonsillar surfaces of 5 patients with acute tonsillitis culture-positive for Streptococcus pyogenes. By using 10 nm gold particles conjugated to antiserum to S. pyogenes it was possible to trace the actual microorganisms when examined in a transmission electron microscope. The S. pyogenes bacteria, usually in pairs, were attached to the epithelial surface by their pili. The bacteria often formed a hollow in the epithelial cell surface. Coccus-shaped bacteria expressing positive affinity to immunogold-labelled antiserum were intermingled with bacteria, often rods, having no affinity whatsoever to the antiserum. With the immunocytological technique outlined in this study it is possible to study more closely cellular/bacterial adhesion mechanisms.

Adolescent↗

PubMed1996

ERp60 does not substitute for protein disulphide isomerase as the beta-subunit of prolyl 4-hydroxylase.

Prolyl 4-hydroxylase (EC 1.14.11.2) catalyses the formation of 4-hydroxyproline in collagens. The vertebrate enzymes are alpha 2 beta 2 tetramers while the Caenorhabditis elegans enzyme is an alpha beta dimer. The beta-subunit is identical to protein disulphide isomerase (PDI), a multifunctional endoplasmic reticulum luminal polypeptide. ERp60 is a PDI isoform that was initially misidentified as a phosphatidylinositol-specific phospholipase C. We report here on the cloning and expression of the human and Drosophila ERp60 polypeptides. The overall amino acid sequence identity and similarity between the processed human ERp60 and PDI polypeptides are 29% and 56% respectively, and those between the Drosophila ERp60 and human PDI polypeptides 29% and 55%. The two ERp60 polypeptides were found to be similar to human PDI within almost all their domains, the only exception being the extreme C-terminal region. Nevertheless, when the human or Drosophila ERp60 was expressed in insect cells together with an alpha-subunit of human prolyl 4-hydroxylase, no tetramer was formed and no prolyl 4-hydroxylase activity was generated in the cells. Additional experiments with hybrid polypeptides in which the C-terminal regions had been exchanged between the human ERp60 and PDI polypeptides demonstrated that the differences in the C-terminal region are not the only reason for the lack of prolyl 4-hydroxylase tetramer formation by ERp60.

Amino Acid Sequence↗

PubMed1996

Bacterial attachment to oropharyngeal epithelial cells in breastfed newborns.

On day 2 post partum, swab samples were obtained from the oropharyngx of 20 healthy, breast-fed babies. The samples were examined for aerobes (culture on agar plates), for bacterial coating with the immunoglobulins SIgA, IgG and IgM (immunofluorescence assay), for bacterial attachment to epithelial cells (fluorescence microscopy of acridine orange stained material, and scanning electron microscopy). alpha-Hemolytic streptococci grew almost exclusively in the oropharynx, while 32% (median value) of the epithelial cells showed bacterial attachment in abundance, viz. > 50 attached bacteria per cell, 66% (median value) of the bacteria showed positive reactivity when treated with anti-human SIgA serum. 72% (median value) of the bacteria were coated with IgG, but no IgM coating of the bacteria could be detected. Newborns do not possess IgA antibodies, as only IgG is able to pass the placental barrier. The SIgA-rich colostrum is capable of coating the oropharyngeal bacteria of breast-fed babies during their first days after birth. However, despite abundant SIgA-coating, bacteria still succeed in attaching to the epithelial cells of the oropharynx. This finding hints that factors other than SIgA impede the bacterial/cellular adhesion mechanism.

Bacterial Adhesion↗

PubMed1996

Immunoglobulin-coated bacteria on the tonsillar surface during infectious mononucleosis.

Sequential bacterial samples were obtained from the tonsillar surface of 19 consecutive patients (12 females, seven males; mean age 16.1 years, range four to 24 years) suffering from infectious mononucleosis with membranous tonsillitis. The specimens were examined with respect to aerobes (culture on blood and chocolate agar plates) and proportions of bacteria coated with immunoglobulins (secretory IgA, IgG, IgM) by using an immunofluorescence assay. In the early stage of the membranous tonsillitis phase, attachment of secretory IgA (SIgA) and IgG to the bacteria was greatly suppressed, as compared with healthy controls. Coating with IgM was evident only late in the membranous tonsillitis phase but was contracted and still evident even after the clinical throat symptoms had abated. The findings suggest that the B-lymphotropic Epstein-Barr virus, causative agent of infectious mononucleosis, exerts a transient suppression of immunoglobulin-coating of bacteria harboured on the tonsillar surfaces, with consequent abundant bacterial attachment to the epithelial cells and massive bacterial colonization on the palatine tonsils.

Adolescent↗

PubMed1996

Bacterial adherence to the surface and isolated cell epithelium of the palatine tonsils.

Bacterial adherence to the oropharyngeal epithelium is a significant factor in normal microecology, etiopathogenesis of diseases (tonsillitis, gingivitis) and possibly also induction of immune response. Bacterial adhesion to human tonsillar epithelium of whole tonsils and swabs was studied by fluorescence, scanning, and transmission electron microscopy. The epithelial cell borders were well demarcated. On the apical surface of the cells there were irregular microridges. All forms of microscopy visualized epithelial cells with attached bacteria, often forming microcolonies on the free surface. Some bacteria formed excavations on the cell surface. Most attached bacteria were coccoid, but variously sized rods were also visible. In transmission electron microscopy, epithelial cells with intracellular bacteria were regularly observed.

Adolescent↗

PubMed1996

In situ localization of Streptococcus pyogenes during acute tonsillitis: an immunocytochemical study with gold markers.

Epithelial cells were harvested from the surface of the palatine tonsils of seven patients with current acute tonsillitis, proven culture-positive for Streptococcus pyogenes. The epithelial cells harboured attached bacteria, which expressed positive affinity to gold-labelled antiserum to S. pyogenes. The gold particles adhered selectively to the bacterial capsules. The microorganisms were held in place by projections protruding from the epithelial cells, which were in close contact with the pili of the bacteria. In some areas, positive immunogold-labelled bacteria intermingled with bacteria lacking such labelling. None of the culture-negative controls harboured epithelial cells with positive immunogold-labelled bacteria. Orally administered phenoxymethylpenicillin caused a significant reduction in both culture-positive S. pyogenes and bacteria displaying positive coating with specific gold-labelled antiserum to S. pyogenes.

Acute Disease↗