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Biomedical subjects

M Nyström

Publications and source records attributed to M Nyström.

At least 19 recordsLinked to original sources
PubMed2001

Effects of the multiple stressors copper and reduced salinity on the metabolism of the hermatypic coral Porites lutea.

This study investigates the physiological responses in the hermatypic coral Porites lutea when exposed to a combination of reduced salinity (from ambient 30 psu to 20 psu) and two concentrations of copper (CuS04), 10 microg 1(-1) and 30 microg 1(-1). Corals were exposed for 14 h and changes in metabolism in terms of primary production rate per chlorophyll a and respiration per surface area (cm2) were used as measures of stress. The results showed no significant changes in respiration rate in any of the treatments compared with controls, or between treatments. The primary production rate, however, displayed a more complex pattern. Corals exposed to reduced salinity, 30 microg 1(-1) copper, and the combination of the two stressors significantly reduced the production rate, whereas corals exposed to 10 microg 1(-1) only, remained unaffected. However, adding 10 microg 1(-1) copper to reduced salinity did not affect the production rate thus indicating an antagonistic effect.

Animals↗
PubMed2001

Emergence of permanent teeth and dental age in a series of Finns.

The emergence of permanent teeth was studied in 187 Finnish children who had longitudinal records of the emergence of all permanent teeth except third molars. Exact emergence dates were known for about one third of the teeth. Emergence ages of the remaining teeth were based on their presence and absence at clinical examinations. We calculated ages at clinical eruption of permanent teeth and tooth counts at half year intervals. Ages corresponding to counts of permanent teeth from 1 to 27 are also given. The schedules presented, which slow means, standard deviations, and percentage distributions, are expected to serve as useful references in clinical dentistry, pediatrics, forensics, and research. The mandibular central incisor emerged before the first molar of the same jaw in 68% of the children. A change in the emergence order of these teeth in Finns seems to have occurred in the 1960s. A visual comparison of dental maturity curves based on tooth counts with curves based on tooth mineralization in a previous Finnish radiographic study showed that the mean curves had roughly the same form, whereas the forms of standard deviation curves differed distinctly. It appears that the two methods to assess dental maturity are not interchangeable in practice. Tooth counts can be used in maturity estimations up to about 13 years of age, whereas the radiographic method works best to about 11 years.

Adolescent↗
PubMed2000

Coral reef disturbance and resilience in a human-dominated environment.

Facing a human-dominated world, ecologists are now reconsidering the role of disturbance for coral reef ecosystem dynamics. Human activities alter the natural disturbance regimes of coral reefs by transforming pulse events into persistent disturbance or even chronic stress, by introducing new disturbance, or by suppressing or removing disturbance. Adding these alterations to natural disturbance regimes will probably result in unknown synergistic effects. Simultaneously, humans are altering the capacity of reefs to cope with disturbance (e.g. by habitat fragmentation and reduction of functional diversity), which further exacerbates the effects of altered disturbance regimes. A disturbance that previously triggered the renewal and development of reefs might, under such circumstances, become an obstacle to development. The implications of these changes for reef-associated human activities, such as fishing and tourism, can be substantial.

Journal Article↗
PubMed2000

Age estimation in small children: reference values based on counts of deciduous teeth in Finns.

The eruption of teeth in the mouth is suitable for age estimations during the period when teeth are actively emerging, in the deciduous dentition phase approximately from the age of 6 months to 2.5 years. Estimations of age can be performed simply by counting the number of teeth in the mouth. Reliability of the estimates depends on the reference data available and each population group should preferably have its own standards. In the present study timing of eruption of successive deciduous teeth was studied longitudinally in 129 Finns. The dates of clinical eruption of deciduous teeth were recorded by mothers and checked by dentists. In 40 of the 129 children emergence ages of at the most the four last teeth were based only on semiannual registrations performed by dentists. The main purpose was to provide normal timetables of tooth eruption in small children in forms that are practical in estimations of dental age. No sexual dimorphism existed in the timing of clinical eruption of successive deciduous teeth. The mean age corresponding to the presence of one tooth in the mouth was 7.1 months (S.D.=1.78) and that corresponding to tooth count 19 was 27.8 months (S.D.=3.99). If the chronological age is known, the presented distributions and means with variations make it possible to estimate the degree of advancement or delay in a child's dental development. If the age of the child is not known, the mean and median ages can be used for estimations of chronological age. However, estimations of age should not be based only on tooth counts because of marked variation also within this homogeneous group.

Adult↗
PubMed2000

Dental maturity in Finns and the problem of missing teeth.

Development of teeth was studied from 2483 dental panoramic tomograms of 1651 healthy Finns ranging in age from 2 to 25 years. Dental maturity was assessed using a method based on developmental stages of 7 left mandibular teeth. We give sex-specific tables of maturity scores as a function of ages and of ages as a function of maturity scores. Also generated are percentile graphs for visual evaluations of dental maturity in children and adolescents. Since maturity scales do not tolerate any missing data, a great limitation for their use, we have developed linear regression models for predicting the formation stages of each of the 7 mandibular teeth. It was easiest to predict the formation stage of the mandibular first molars (correct in 87% within the study material) and most difficult to predict second molars and second premolars (correct in 69% and 70%, respectively). We expect the data and formulae presented in this study to prove useful in research and in clinical and forensic dentistry.

Adolescent↗
PubMed1999

Production of secretory leucocyte protease inhibitor (SLPI) in human pancreatic beta-cells.

Secretory leucocyte protease inhibitor (SLPI) is a potent inhibitor of granulocyte elastase and cathepsin G, and also an inhibitor of pancreatic enzymes like trypsin, chymotrypsin and pancreatic elastase. SLPI has also been shown to inhibit HIV-1 infections by blocking viral DNA synthesis. Since SLPI is an inhibitor of pancreatic proteases we wished to investigate whether SLPI was also actually produced in the pancreas. M-RNA from human pancreatic tissue showed evidence of SLPI production using the reverse transcriptase polymer chain reaction technique (RT-PCR). Using immunohistochemical methods SLPI was demonstrated in the beta-cells of the islets of Langerhans. The function could be local protease/antiprotease regulation or antiviral/antibacterial defence in the close vicinity of the cell surface, or even inside the beta-cell itself.

Adenocarcinoma↗
PubMed1998

Modification of ultrafiltration membrane with gelatin protein.

A dye-binding procedure was developed for the analysis of protein attached to the membrane, with bound and adsorbed forms of attachment being distinguished. The relationship between modification procedure and protein attachment was explored and related to flux, streaming potential, and rejection with variation of pH. The effects of attaching four different types of gelatin to the membrane were studied. Assessment was made of modifications for improvement of flux and selectivity in the presence of protein foulants.

Animals↗
PubMed1997

The elimination of secretory leukocyte protease inhibitor (SLPI) from the gastrointestinal tract in man.

Secretory leukocyte protease inhibitor (SLPI) is the dominant protease inhibitor in the mucus secretions of the genital and respiratory tract and it was recently also detected in intestinal mucosa. Furthermore an earlier study showed high concentrations of SLPI in peritoneal fluid from patients with perforations of the large and small intestines. As SLPI is acid-stable, this raised the question of to what extent swallowed SLPI may contribute. The present study investigated the turnover of swallowed SLPI in the gastrointestinal tract. Native 125I-labelled SLPI was instilled in the duodenum of three healthy volunteers and radioactivity in plasma, faeces and urine was measured. Within 72 h 81.4% of the injected radioactivity was excreted in urine and 3.6% in faeces as radioactive low molecular weight proteins (< 1 kDa). Recombinant human SLPI (rh-SLPI) was incubated with porcine pepsin or human gastric or duodenal juice. This resulted in rapid degradation of SLPI to smaller molecules. In conclusion, SLPI is rapidly degraded in the stomach and duodenum. There were no measurable amounts of SLPI in the faeces. We have shown that during normal conditions, swallowed SLPI was rapidly degraded in the stomach and duodenum, and therefore it probably can not be of any importance for inflammatory diseases in the intestines.

Chromatography, Gel↗
PubMed1996

Does clicking in adolescence lead to painful temporomandibular joint locking?

BACKGROUND: It has been assumed that clicking of the temporomandibular joint (TMJ) may predispose to closed locking. Although jaw clicking is a common complaint, locking of the TMJ is rare. METHODS: To assess whether clicking is a reliable predictor of locking, we examined longitudinally over 9 years the variation of reported and recorded TMJ clicking in 128 young Finnish adults. Subjects were interviewed and examined at the ages of 14, 15, 18, and 23 years. FINDINGS: Reported and recorded TMJ clicking both increased significantly with age, varying from 11% to 31% and from 11% to 34%, respectively, However, clicking showed no predictable pattern, and only a few subjects consistently reported clicking (2%) or had it recorded (2%). None developed locking. INTERPRETATION: Because none of the young adults developed locking of the TMJ, we suggest treatment for clicking should be conservative.

Adolescent↗
PubMed1996

Localization of immunoreactive secretory leukocyte protease inhibitor (SLPI) in intestinal mucosa.

Secretory leukocyte protease inhibitor (SLPI) is the dominant protease inhibitor in the mucus secretions of the repiratory and genital tracts, and local production seems likely, as immunoreactive SLPI has been found in the corresponding mucosa. To our knowledge, SLPI has not been previously demonstrated in intestinal epithelia or secretions. In an earlier study, however, we found surprisingly high levels of SLPI in peritonitis exudate from patients with gastrointestinal perforations. This study extends these observations by demonstrating the presence of immunoreactive SLPI in intestinal mucosa. In the small intestine, SLPI was present in Paneth cells and in scattered mucosa cells of goblet-type. In normal mucosa of the large bowel, SLPI was also found in scattered cells of goblet-type in the epithelium. In addition, immunoreactive SLPI was frequently found in colonic adenomas. The findings in this study raise several interesting questions on the possible role of SLPI in the gut epithelial defense against inflammatory assaults.

Adenoma↗
PubMed1995

Radiographic characteristics in mandibular condyles of orthodontic patients before treatment.

Pretreatment panoramic radiographs and patient files of 625 orthodontic patients (269 males and 356 females), aged 4-15.9 years (mean 11.0, SD 1.7) were evaluated with special emphasis on the mandibular condyles and malocclusions. Radiographic characteristics in the mandibular condyle were seen in 14 children (2.2 per cent), comprising six boys (2.2 per cent) and eight girls (2.3 per cent). There were no statistically significant differences between orthodontic patients before treatment and normal population controls (n = 410,229 males and 181 females, mean age 11.4 years, SD 1.8). No statistically significant difference in the frequency of condylar characteristics was found between younger (under 12) and older (over 12) children. Angle Class II molar relationship was the only type of morphological malocclusion associated (P < 0.05) with condylar characteristics. The means of several cephalometric measurements in the children with condylar characteristics were close to those of children with harmonious skeletal relationships.

Adolescent↗
PubMed1995

A follow-up study of radiographic findings in the mandibular condyles of orthodontically treated patients and associations with TMD.

Our earlier studies have shown that some radiographic structural findings in the mandibular condyles are more common in orthodontically treated populations than in normal populations. To test the hypothesis that these findings are stable, we studied condylar findings in panoramic radiographs longitudinally in 39 subjects and in 39 sex- and age-matched controls. The subjects had condylar findings at the end of orthodontic treatment at about 15 years of age; no such findings were seen in the controls. The subjects and controls were re-examined radiographically about 12 years after the posttreatment radiographic examination. We also tested the hypothesis that radiographic condylar findings are associated with temporomandibular disorders (TMD). No statistically significant differences were found between subjects and controls in terms of reported subjective TMD symptoms. Clinically, the subjects had temporomandibular joint (TMJ) crepitation significantly more frequently (27%) than controls (8%) (p < 0.05). Crepitation correlated with some reported symptoms and clinical signs, suggesting that osteoarthrosis might have been an important etiological factor for TMD in the present subjects. At the follow-up examination, radiographic condylar findings were seen in 25 subjects and in four controls (p < 0.001). The condylar findings varied greatly between the time of orthodontic treatment and follow-up in the subjects. The findings had become more severe in 49% of the subjects, more often in females than in males (p < 0.05), whereas in 28% of the subjects the condylar findings had disappeared. Although the radiographic findings after orthodontic treatment fluctuated with age, in most adolescents with changes in their condyles, these findings remained constant or became more severe.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Radiographic structural findings in the mandibular condyles of young individuals receiving orthodontic treatment.

Radiographic findings in mandibular condyles were studied from the pre- and post-treatment panoramic radiographs of 625 orthodontic patients. The subjects' mean age was 11 years at the start and 14 years at the end of active orthodontic treatment. Radiographic condylar findings were seen in 14 (2%) subjects before treatment and in 54 subjects (9%) after treatment (p < 0.001). In age-related controls (n = 783) condylar findings were seen in 3% (p < 0.001). The condylar finding was 'flattening only' in half of the patients and in one-third of the controls with condylar findings. Activator treatment was associated with condylar findings (p < 0.05). Condylar findings increased with age in the orthodontically treated subjects (p < 0.05) but not in the unselected population controls. This may mean that condyles become more sensitive with age in children. Increase with age may be partly due to the radiographic interpretation, since minor condylar findings are difficult to observe in young children, and partly due to differences in treatment modalities and the duration of treatment.

Activator Appliances↗
PubMed1995

Using data preprocessing and single layer perceptron to analyze laboratory data.

During daily work in hospitals a large amount of clinical data is produced each day. Totally computerized patient records are not yet widely used but a large part of essential information is already stored on computer files. These include laboratory test results, diagnoses, codes for operations, codes of histopathological diagnoses and maybe even the patient's medication. Accordingly, these databases include much clinical knowledge that would be useful for clinicians. Laboratories try to support clinicians by producing reference values for laboratory tests. It is, of course, necessary information but, however, it does not give very much information about the weight of evidence that an abnormal laboratory test will give in special clinical settings. We have developed a software package - DiagaiD - in order to build a smart link between patient databases and clinicians. It utilizes neural network-based machine learning techniques and can produce decision support which meets the special needs of clinicians. From example cases it can learn clinically relevant transformations from original numeric values to logical values. By using data transformation together with a single layer perceptron it is possible to build nonlinear models from a set of preclassified example cases. In this paper, we use two small datasets to show how this scheme works in the diagnosis of acute appendicitis and in the diagnosis of myocardial infarction. Results are compared with those obtained using logistic regression or backpropagation neural networks. The performance of our neuro-fuzzy tool seemed to be slightly better in these two materials but the differences did not reach statistical significance.

Appendicitis↗
PubMed1995

Fractionation of BSA and myoglobin with modified and unmodified ultrafiltration membranes.

Fractionation of the model proteins, bovine serum albumin and myoglobin, was studied with modified and unmodified polysulfone ultrafiltration membranes. A commercial polysulfone ultrafiltration membrane with a nominal cut-off value of 50,000 g mol-1 was used as the reference membrane, and it was modified with ultraviolet irradiation in different protein solutions. The permeate fluxes and the streaming potentials of the membranes were measured simultaneously. Ultrafiltration experiments were carried out at the isoelectric points of the proteins. The results show that the fractionation can best be carried out at the isoelectric point of myoglobin. Modification of the membranes with bovine serum albumin resulted in smaller adsorption and flux reduction, while membranes modified with myoglobin were more selective for myoglobin.

Animals↗
PubMed1994

Effect of timing and method of closure of isolated cleft palate on development of dental arches from 3 to 6 years of age.

Development of the dental arches from 3 to 6 years of age was followed in 120 children with isolated cleft palate (ICP) and in 50 non-cleft (NONC) children. In 60 of the ICP children the palate had been repaired at the age of 1.8 years (SD = 0.2) and in the other 60 at the age of 1.1 years (SD = 0.1). In both groups the one-stage soft and hard cleft palate closure had been performed using the mucoperiosteal palatal V to Y push-back technique (Veau-Wardill-Kilner) or the Cronin modification. The purpose of this study was to compare the effect of the two different ages and the two different methods of palatal repair on the development of dental arches. The growth increment in maxillary canine and molar width, and posterior palatal height during the 3-year period was greater in the group with late palatal repair. In children with no secondary palatal repair, when the primary repair had been done with the V to Y method, the increase in maxillary canine width was greater than with the Cronin modification. On the other hand, when the V to Y technique was used, velopharyngoplasties were more frequent. The means of maxillary canine and molar width decreased in children with velopharyngoplasties, and increased in the others. Dental arches of ICP children were significantly smaller than those of NONC children, and the discrepancy increased during the period from 3 to 6 years of age, and increased more in the maxilla than in the mandible.

Age Factors↗
PubMed1994

Carbohydrate-deficient transferrin during 3 weeks' heavy alcohol consumption.

To study the effect of controlled heavy drinking of 60 g ethanol/day for 3 weeks on carbohydrate-deficient transferrin (CDT), a commercial double antibody kit (CDTect) was used. By the end of the third drinking week, a statistically significant increase in the mean CDT level was observed. When compared to AST and gamma-glutamyltransferase, CDT was a more informative marker. However, only in 2 of the 10 volunteers did CDT exceed the upper normal level (20 units/liter) recommended by the manufacturer. This indicates that the sensitivity of CDT to detect heavy drinking is lower than that previously reported. The higher accuracy has in general been obtained in studies comparing healthy controls with a low alcohol consumption to alcoholics with an alcohol consumption higher than that used in the present experiment. Our results suggest that it remains to be established whether CDT, although better than AST and gamma-glutamyltransferase, will provide a clinically useful tool in identifying heavy drinkers in populations covering a wide range of alcohol consumption.

Adult↗