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Biomedical subjects

R Lappalainen

Publications and source records attributed to R Lappalainen.

At least 37 records · Page 2Linked to original sources
PubMed1999

Recent body-weight changes and weight loss practices in the European Union.

OBJECTIVES: The aim of this paper is to describe recent weight changes and weight loss practices in the EU, and in particular to describe the group of subjects who were in a recent state of weight gain. DESIGN AND SUBJECTS: Overall, 15,239 adults aged 15 years and upwards composed of 1000 from each EU member state were selected to complete the interview-assisted face-to-face questionnaire. In each member state, sample selection was quota-controlled to ensure national representativeness. RESULTS: This survey points to a fairly alarming tendency of more normal weight, overweight or obese European people being in a state of weight gain rather than weight loss. But it is also worrying that almost a fifth of underweight people are in the process of losing more weight. The recommendations for interventions to promote weight loss might be somewhat different between countries in the EU as the common weight loss practices differ between such countries. Overall, a campaign alone may not be effective in encouraging people to do more physical activity in Europe. Additional methods should be found. Furthermore, a combination of diet and exercise as a method of weight control is underestimated or undervalued by the general population who are either overweight or obese.

Adolescent↗
PubMed1999

Difficulties in changing the diet in relation to dietary fat intake among patients with coronary heart disease.

OBJECTIVE: To study barriers in following nutritional advice among coronary heart disease patients in relation to dietary fat intake. DESIGN: A cross-sectional study using 4-day food records and a questionnaire with regard to barriers to or difficulties in following dietary advice. SUBJECTS: Altogether, 362 male subjects with coronary heart disease from two separate patient populations (91 + 271) were included in the study, with the mean age of 50 years and 60 years, respectively. The patients were classified into low (< or = 30 E%) or high (> 30 E%) fat intake groups. The patients with low dietary fat intake obtained on an average 10 E% less energy from fat as compared to the high dietary fat intake group. RESULTS: Overall, most patients with coronary heart disease reported difficulties in following nutritional advice when eating in social situations. Patients with high dietary fat intake reported more frequently than patients with low fat intake that they eat like other people without thinking about what they eat. On the other hand, there were no differences between the high and low fat intake groups in the barriers: eating at work, food price, shopping, taste or knowledge of nutrition. CONCLUSIONS: Our results suggest that the sensitivity to social influence is an important factor explaining noncompliance with dietary advice among patients with high dietary fat intake.

Coronary Disease↗
PubMed1999

The counterface, surface smoothness, tolerances, and coatings in total joint prostheses.

Proper counterface material combinations, surface finish, and tolerances of contact surfaces are important issues in minimizing friction, wear, and corrosion of total joint prostheses. In the current study, the potential of novel amorphous diamond coatings to solve some present problems in total joint prostheses was studied by using tribological tests with a hip joint simulator and pin-on-disk testers. Based on the tests, the wear of amorphous diamond is negligible compared with conventional hip joint materials (10,000 to 1,000,000 times lower). The coefficient of friction of diamond-coated artificial hip joint was 0.03 to 0.06 when tested in saline solution with loads from 200 to 1000 kg for as many as two million cycles. The friction remained stable throughout the tests. Methylmethacrylate (bone cement) is a typical source of third body wear particles in cemented total hip replacements. The wear tests showed that bone cement (containing hard ceramic particles of barium sulfate or zirconia) severely scratched cobalt chromium molybdenum alloy samples. These scratches enhance the wear of softer counterpart materials, such as polyethylene or bone cement, whereas diamond-coated surfaces remained undamaged. High quality amorphous diamond coatings offer superior stability (minimal wear debris release in surrounding tissues) and good biomechanical performance.

Acetabulum↗
PubMed1998

Reasons for initiation and cessation of eating in obese men and women and the affective consequences of eating in everyday situations.

Reasons for the initiation and termination of eating were investigated in 78 female and 36 male obese subjects following a weight control programme. Self-monitoring diaries were completed during a 24-h period, in which subjects selected the main reason for starting and stopping an eating episode. Additionally, subjects recorded mood before and after eating using visual analogue scales. Hunger was chosen as a reason to start eating in only 20% of cases. Environmental cues such as mealtime were selected as the main reason for the initiation of the majority of eating episodes. In contrast, self-assessments such as "I felt I had eaten enough" was the main reason for terminating eating (39.4%). Gender differences in the reasons for initiating eating revealed a greater tendency for men to initiate eating for environmental reasons than women, whereas the opposite was found for the termination of eating, with women more likely to stop eating for environmental reasons than men. Changes in affect during eating revealed a significant decline in negative emotions such as tension and tiredness, and in the heavier subjects a trend for increased happiness was observed following eating. As hunger was less commonly reported as a reason to start eating than external reasons, treatment strategies for the obese might benefit by targeting individual reasons for meal initiation.

Affective Symptoms↗
PubMed1998

Biocompatibility of silicon carbide in colony formation test in vitro. A promising new ceramic THR implant coating material.

We studied the possible use of silicon carbide (SiC) as a ceramic coating material of titanium-based total hip replacement (THR) implants. The idea is to prevent wear debris formation from the soft titanium surface. SiC is a hard and tightly bonding ceramic surface material, and because of these physical properties it is not easily degradable, as is the case with hydroxyapatite. Our previous in vivo and in vitro studies have indicated that SiC and hydroxyapatite are equally biocompatible regarding particle size for phagocytosis. The present cytotoxicity test using JCRB0603 cells showed that 5 microns SiC particles inhibited colony outgrowth by one-third (67% + 10% vs control), while SiC-coated pins did not cause any inhibition and acted similarly to uncoated titanium pins. The results support the hypothesis that SiC is a promising ceramic THR implant coating material.

Carbon Compounds, Inorganic↗
PubMed1998

Systemic administration of atipamezole, a selective antagonist of alpha-2 adrenoceptors, facilitates behavioural activity but does not influence short-term or long-term memory in trimethyltin-intoxicated and control rats.

The present study used trimethyltin (TMT)-intoxicated rats as a model for the behavioural syndrome seen after neuronal damage to the limbic system. Behavioural assessments indicated increased locomotor activity and reduced number of groomings in an open-arena task in TMT-intoxicated (6.6 mg/kg as a free base) rats, as has been found previously. A novel finding was the severe deficit in swimming to a visible platform in the water maze task, with reduced swimming speed at the beginning of the training period. During the reacquisition phase of a radial arm maze task, TMT-intoxicated rats made more short-term and long-term memory errors, and their behavioural activity was increased in comparison with controls. The administration of atipamezole (300 micrograms/kg), a selective antagonist of alpha 2-adrenoceptors, enhanced locomotor activity compared to saline-treated rats, but these effects did not differ between the TMT group and their controls. Atipamezole did not enhance short-term or long-term memory in either TMT or control groups. Taken together, the present data indicate that TMT intoxication is a model for global dementia rather than for a specific loss of relational memory. Previous studies on the neurochemical effects of TMT and the alleviation or prevention of neurotoxicity of TMT are reviewed.

Adrenergic alpha-2 Receptor Antagonists↗
PubMed1998

Diamond coated total hip replacements.

Diamond has many superior, desired characteristics of implant materials such as low friction, high wear and corrosion resistance, and well bonding surface to bone. The potential of diamond for total hip replacement implants was studied in the form of amorphous diamond coatings on conventional metal implant materials. Amorphous diamond coatings (sp3 bonding fraction 80%, thickness 0.2 to 10 microns) were deposited on stainless steel AISI316L, Ti6A14V, and CoCrMo alloys using filtered pulsed plasma are discharge method. Superior attachment of coatings to the implant materials was achieved by using high energy plasma beams to deposit amorphous diamond and proper intermediate layers. Previously it was shown that these coatings are biocompatible causing no local tissue reactions. Tribologic studies using a pin on disk apparatus with coated or uncoated implant materials in 1 wt.% NaCl distilled water were performed. A simplified hip joint simulator was used for preliminary testing of metal on polyethylene and metal on metal artificial hip joints modified with amorphous diamond coating. The average coefficients of friction were typically in the range of 0.03 to 0.11 for amorphous diamond coated materials. In the case of metal on metal hip implants, the average friction during initial running in period was improved (coefficient of friction = 0.07) compared with the same metal on metal pair (coefficient of friction = 0.22) and sliding was significantly smoother. In pin on disk wear tests, the average wear factors obtained were 140.10(-6), 5.0.10(-6), and << 0.1.10(-6) mm3/Nm for the pairs of AISI316L, CoCrMo, and the same materials with amorphous diamond coating. The corrosion rates of these implant materials in 10 wt.% HCl solution were decreased by a factor of 10,000 to 15,000 and any damage of the coatings was not observed in 6 months. The results of the tests show that in all the combinations studied, amorphous diamond coating improved definitely the wear and corrosion resistance compared with the uncoated materials.

Biocompatible Materials↗
PubMed1997

Alpha2-adrenergic control of dopamine overflow and metabolism in mouse striatum.

The effects of the alpha2-adrenoceptor drugs, medetomidine and atipamezole, on dopamine overflow evoked by low (6 Hz-10 s) and high (50 Hz-4 s) frequency electrical stimulation of the median forebrain bundle were studied in striatum of BALB/C mice anaesthetized with chloral hydrate with fast in vivo voltammetry techniques. The effects of these drugs on the basal concentrations of dopamine metabolites were also investigated by means of differential pulse voltammetry. Medetomidine dose dependently decreased dopamine overflow in nucleus accumbens in the dose range 5-100 microg/kg, s.c. This effect was seen only at low frequency stimulation and reached 85% at a dose of 100 microg/kg. Medetomidine also decreased the basal concentration of striatal homovanillic acid. This effect did not exceed 35%. Atipamezole antagonized the inhibitory effects of medetomidine on the dopamine overflow. but showed no effect itself. We suggest that alpha2-adrenoceptors in dopaminergic terminal fields in the mouse striatum are involved in the regulation of dopamine release at physiological stimulation frequencies.

Adrenergic alpha-Agonists↗
PubMed1997

Healthy dietary practices among European students.

Predictors of 5 healthy dietary habits were examined in data from the European Health and Behaviour Survey (A. Steptoe & J. Wardle, 1996), a study of over 16,000 students from 21 European countries. The level of practice of these healthy dietary habits was low. Significant univariate associations with healthy dietary habits were identified for gender, weight, dieting status, dietary health beliefs, nutrition knowledge, and health locus of control. In multivariate analyses, only gender, dieting status, and dietary health beliefs were significant predictors of healthy dietary habits. The practical implications of these results for dietary health promotion are discussed.

Adult↗
PubMed1997

Serum leptin and short-term regulation of eating in obese women.

1. Leptin is generally thought to play a key role in the regulation of eating. However, its real role in human eating behaviour is still poorly known. Therefore, the role of leptin in the regulation of eating was examined in obese binge- and non-binge-eating women during exposure to food and food-related stimuli. 2. Eleven binge- and ten non-binge-eating obese women took part in the study. In addition to serum leptin, serum insulin, non-esterified fatty acids, plasma glucose, salivation, the feeling of hunger and the desire to eat were repeatedly measured during the experiment. 3. Serum leptin levels did not differ between the binge- and non-binge-eating women. Neither were leptin levels associated with the feeling of hunger or the desire to eat food, nor with the amount or composition of food eaten. During food exposure leptin levels did not change, whereas at the same time serum insulin levels increased and serum non-esterified fatty acid levels decreased. The change in salivation during food exposure was inversely associated with the fasting leptin level. 4. This study indicates that serum leptin does not play a role in the regulation of eating in obese women, at least not in the short term. Furthermore, leptin levels are not different in obese binge-eating women as compared with obese non-binge-eating women. Interestingly, high fasting leptin levels may be associated with a decreased salivation response in the presence of food and food-related stimuli.

Adult↗
PubMed1997

Brain perfusion SPECT and EEG findings in Rett syndrome.

Thirteen patients (mean age 8.4 + 5.3 years) with Rett syndrome (RS) were studied with EEG and 99mTc-HMPAO SPECT. Eleven patients had background abnormalities and 10 patients paroxysmal activity in EEG. Hypoperfusion of varying severity was detected in 11 patients, 7 patients having multiple lesions. Bifrontal hypoperfusion, observed in 6 patients, was the most distinctive finding. Hypoperfusion was observed also in other cortical regions, except for the occipital lobes. There was no correlation between severity of the background abnormality or presence of paroxysmal activity in EEG and grade of hypoperfusion. There was, however, an association between the severity of hypoperfusion and early manifestation of symptoms in patients with RS. Whether this early-onset group of patients represents a different disease entity or only reflects disease variability the basic pathology being the same, is a possibility that deserves further clarification.

Adolescent↗
PubMed1997

Sources used and trusted by nationally-representative adults in the European Union for information on healthy eating.

OBJECTIVE: To assess what sources of information on healthy eating are used and in particular to ascertain which are the most trusted by European adults. DESIGN: A cross-sectional study in which quota-controlled, nationally-representative samples of approximately 1000 adults from each country completed a face-to-face interview-assisted questionnaire. SETTING: The survey was conducted between October 1995 and February 1996 in the 15 member states of the European Union. SUBJECTS: 14331 subjects (aged 15 y upwards) completed the questionnaire. Data were weighted by population size for each country and by sex, age and regional distribution within each member state. RESULTS: The five sources of information most frequently selected were: TV/radio (29%), magazines and newspapers (27%), health professionals (26%), food packages (22%) and relatives/friends (22%). Those used by less than 5% of the population included vegetarian and slimming societies and women's organizations. The reliance on health professionals for information was stronger for females and tended to increase with age. The most trusted sources of information in almost all countries were health professionals (91%) and government agencies (80%) with great consistency across countries. 15% of Europeans stated that they did not get any information on healthy eating.

Adolescent↗
PubMed1997

Difficulties in trying to eat healthier: descriptive analysis of perceived barriers for healthy eating.

OBJECTIVE: To determine the factors which are perceived to be important barriers to healthy eating among European adults. DESIGN: A cross sectional study in which quota-controlled, nationally-representative samples of approximately 1000 adults from each country completed a face-to-face interview-assisted questionnaire. SETTING: The survey was conducted between October 1995 and February 1996 in the 15 member states of the European Union. SUBJECTS: 14,331 subjects (aged 15 y upwards) completed the questionnaire. Data were weighted by population size for each country and by sex, age and regional distribution within each member state. RESULTS: The study demonstrates a great variability in the perceived barriers to healthy eating between different EU countries. Lack of time was the most frequently mentioned difficulty among EU subjects for not following nutritional advice (24% of total EU sample). This barrier was frequently reported by the younger and the higher education people. Other frequently reported barriers were giving up favourite foods (23%) and willpower (18%). Thus healthy diets do not appear to be viewed as an easy or attractive alternative to current diets. There was wide geographical variation in the number of subjects mentioning price as an important barrier to healthy eating (15% in overall EU sample) ranging from less than 10% in Germany and Italy to 23% in the UK and 24% in Luxembourg.

Adolescent↗
PubMed1997

Systemic administration of atipamezole, an alpha 2-antagonist, can reduce scopolamine-induced hyperactivity in rats.

The present study investigated whether an alpha 2-adrenoceptor antagonist (atipamezole) can influence hyperactivity induced by the systemic administration of scopolamine. In the water maze (WM) task, scopolamine (scop) 0.25 mg/kg treatment significantly increased swimming speed during the acquisition phase of this task. Atipamezole (ati) 30 micrograms/kg slightly reduced swimming speed both in saline- and in scop-treated rats. Ati 300 micrograms/kg slightly reduced swimming speed in saline-treated rats, and it prevented the scop-induced increase in swimming speed, because ati300-scop treated rats swam more slowly than the saline-saline group. In addition, ati 300 micrograms/kg reduced the total distance swum in scop-treated rats during a free swim trial (the platform was removed from the pool) performed 1 day after the acquisition phase of the WM test, even though it did not affect this parameter when administered alone. In the open arena task, which assessed the ambulation of rats when the pool was covered with a solid floor, scopolamine dose-dependently increased locomotor activity. The rats ambulated more when treated with scop 0.50 mg/kg compared to vehicle treatment, whereas the effect of scop 0.25 mg/kg treatment did not reach significance. In a test investigating the effects of ati 300 micrograms/kg and scop 0.50 mg/kg given singly or combined, the rats ambulated more during both ati 300 micrograms/kg and scop 0.50 mg/kg treatments given alone, but when combined, the rats ambulated less than during scop-saline treatment even though this was more than during control (saline-saline) treatment. These results indicate that the systemic administration of an alpha 2-antagonist can reduce hyperactivity induced by scopolamine.

Adrenergic alpha-2 Receptor Antagonists↗
PubMed1996

Quantification of antimony depth profiles in Sb-doped tin dioxide thin films.

Sb-doped SnO(2) thin films, deposited by atomic layer epitaxy (ALE) for gas sensor applications, have been characterized by secondary ion mass spectrometry (SIMS). Quantification of the depth profile data has been carried out by preparing a series of ion implanted standards. Average concentrations determined by SIMS have been compared with Sb/Sn ratios obtained by X-ray fluorescence (XRF) spectrometry and proton induced X-ray emission (PIXE) spectrometry and have been found to be in good agreement. However, a detection limit of 5x10(18) at cm(-3) could only be obtained because of mass interferences. SIMS data show that the ALE technique can be used to produce a controllable growth and doping of thin films.

Journal Article↗
PubMed1996

Benign response to particles of diamond and SiC: bone chamber studies of new joint replacement coating materials in rabbits.

Wear particles from total joint replacements are thought to accelerate prosthetic loosening. Diamond coating may improve the smoothness and wear characteristics of the femoral head component of total hip replacements, and thus increase their longevity. The brittleness of a thin diamond coat may be overcome by using an SiC-whisker diamond composite. This study describes the reactions of regenerating bone tissue to phagocytosable particles of diamond and SiC, using implanted bone harvest chambers in rabbits. The particles were dispersed in hyaluronan and introduced into a canal transversing the implant. The tissue that entered the canal during the following 3 weeks was then harvested. In previous studies using this model, particles of high density polyethylene, bone cement and chromium-cobalt all caused an inflammatory reaction and a marked decrease in the amount of ingrown bone. In the present study, neither the diamond nor the SiC particles caused any decrease in bone formation. It appears that particles of diamond and SiC are comparatively harmless.

Animals↗
PubMed1996

High levels of cerebrospinal fluid glutamate in Rett syndrome.

Rett syndrome is a neurodevelopmental disease affecting girls. The cause is not known. Roles for trophic factors and excitatory neurotransmitters have been postulated. To study the significance of excitatory amino acids in Rett syndrome, we determined glutamate and aspartate concentrations in the cerebrospinal fluid from 11 girls with Rett syndrome (age 8 years 4 months +/- 5.7 years, mean +/- SD) and 11 controls (age 7 +/- 4.2 years). In the patients with Rett syndrome, the mean of cerebrospinal fluid glutamate concentration was 355.2 nmol/L (SD +/- 109.2 nmol/L). In the controls it was 203.9 nmol/L (SD +/- 55.5 nmol/L). In Rett syndrome cases, cerebrospinal fluid glutamate concentrations were significantly higher (P = 0.0006) than in the controls. In the Rett syndrome group, the mean cerebrospinal fluid aspartate concentration was 119.4 nmol/L (SD +/- 43.5 nmol/L). In the control group, it was 90.9 nmol/L (SD +/- 20.9 nmol/L). The difference between the cerebrospinal fluid aspartate values was not significant. Glutamate may therefore play an important role in the primary pathogenesis in Rett syndrome. Further investigations are needed, with recognition of possible actions of neuronal growth factors and excitatory neurotransmitters in the damage mechanisms of Rett syndrome.

Adolescent↗