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1.
Heliyon ; 10(11): e32128, 2024 Jun 15.
Article in English | MEDLINE | ID: mdl-38882273

ABSTRACT

Background: Adherence to exercise is crucial for promoting health and maintaining functioning. Aims: To investigate predictors of adherence to exercise in the initially free supervised fall prevention RCT and its low-cost, self-sustained continuation among elderly women. Methods: In the 2-year Kuopio Fall Prevention Study RCT, 457 women (aged 71-84) were offered a free initial 6-month supervised weekly training program (gym, Tai Chi) in the municipal facilities. Women's adherence during this period was categorized into high (≥80 %) and low (<80 %). In the next six months, their free access to the premises continued without supervision. For the second year, low-cost access was offered with unsupervised independent training in these facilities. The second-year adherence was based on purchasing(yes/no) a gym card to continue exercising. Information on baseline health, functioning, and lifestyle was obtained by mailed questionnaires and physical tests. Results: For the first six months, over 60 % of the women had high adherence. Only 26 % continued into the second year. For both follow-up years, active training history was related to better adherence. Initial predictors were related to mental health i.e. having less often fear of falls limiting one's mobility, ability to cope with external, not internal hostility, and being in a loving relationship. In the second year, predictors were related to younger age, having less frequent fear of falls, better functional capacity i.e. better strengths (grip and leg extension) and faster Timed "Up and Go" -test. Conclusion: Better mental and physical health, better functional capacity and active training background were associated with higher adherence to exercise intervention in older women.

2.
Biol Lett ; 12(1): 20150660, 2016 Jan.
Article in English | MEDLINE | ID: mdl-26763215

ABSTRACT

Environmentally transmitted, opportunistic bacterial pathogens have a life cycle that alternates between hosts and environmental reservoirs. Resources are often scarce and fluctuating in the outside-host environment, whereas overcoming the host immune system could allow pathogens to establish a new, resource abundant and stable niche within the host. We tested if short-term exposure to different outside-host resource types and concentrations affect Serratia marcescens-(bacterium)'s virulence in Galleria mellonella (moth). As expected, virulence was mostly dictated by the bacterial dose, but we also found a clear increase in virulence when the bacterium had inhabited a low (versus high) resource concentration, or animal-based (versus plant-based) resources for 48 h prior to injection. The results suggest that temporal changes in pathogen's resource environment can induce very rapid changes in virulence and affect infection severity. Such changes could also play an important role in shifts from environmental lifestyle to pathogenicity or switches in host range and have implications for the management of opportunistic pathogens and disease outbreaks.


Subject(s)
Bacterial Load , Moths/microbiology , Serratia marcescens/pathogenicity , Adaptation, Biological , Animals , Environment , Host-Pathogen Interactions , Larva/microbiology , Life Cycle Stages , Serratia marcescens/metabolism , Virulence
3.
Appl Radiat Isot ; 106: 189-94, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26363564

ABSTRACT

A total of 98 patients with glioma were treated with BPA-F-mediated boron neutron capture therapy (BNCT) in Finland from 1999 to 2011. Thirty-nine (40%) had undergone surgery for newly diagnosed glioblastoma and 59 (60%) had malignant glioma recurrence after surgery. In this study we applied a closed 3-compartment model based on dynamic (18)F-BPA-PET studies to estimate the BPA-F concentrations in the tumor and the normal brain with time. Altogether 22 patients with recurrent glioma, treated within the context of a clinical trial, were evaluated using their individual measured whole blood (10)B concentrations as an input to the model. The delivered radiation doses to tumor and the normal brain were recalculated based on the modeled (10)B concentrations in the tissues during neutron irradiation. The model predicts from -7% to +29% (average, +11%) change in the average tumor doses as compared with the previously estimated doses, and from 17% to 61% (average, 36%) higher average normal brain doses than previously estimated due to the non-constant tumor-to-blood concentration ratios and considerably higher estimated (10)B concentrations in the brain at the time of neutron irradiation.


Subject(s)
Boron Neutron Capture Therapy , Boron/pharmacokinetics , Brain Neoplasms/radiotherapy , Glioblastoma/radiotherapy , Radiotherapy Dosage , Finland , Humans
4.
J Food Prot ; 74(11): 1891-901, 2011 Nov.
Article in English | MEDLINE | ID: mdl-22054190

ABSTRACT

The aim of this study was to determine whether process hygiene in the beverage industry could be improved by applying new coating techniques to process surfaces. Photocatalytic titanium dioxide (TiO(2)) and hydrophobic coatings applied to stainless steel with or without added antimicrobial compounds were studied in laboratory attachment tests and in a 15-month process study. No clear reductions in numbers of attached microbes were obtained with photocatalytic coatings, except for coatings to which silver had been added. These TiO(2)+Ag coatings reduced microbial coverage in laboratory studies and in some process samples. Hydrophobic coatings reduced the area coverage of microorganisms in 4-h laboratory studies but did not affect colony counts in laboratory or process studies. The surfaces had changed from hydrophobic into hydrophilic during the process study. The coatings did not mechanically fully withstand process conditions; part of the hydrophobic coatings had peeled off, most of the precipitated Ag had dissolved, and some of the TiO(2) coatings were damaged. In conclusion, functional coatings have potential for reducing microbial loads on beverage industry surfaces, but these coatings need further development.


Subject(s)
Anti-Bacterial Agents/pharmacology , Bacteria/drug effects , Beverages/microbiology , Disinfection/methods , Stainless Steel/chemistry , Bacteria/growth & development , Biofilms , Colony Count, Microbial , Consumer Product Safety , Food-Processing Industry/standards , Humans , Hydrophobic and Hydrophilic Interactions , Microbial Sensitivity Tests , Silver/pharmacology , Surface Properties , Titanium/pharmacology , Zinc/pharmacology
5.
J Evol Biol ; 24(12): 2563-73, 2011 Dec.
Article in English | MEDLINE | ID: mdl-21902750

ABSTRACT

Temporal resource fluctuations could affect the strength of antagonistic coevolution through population dynamics and costs of adaptation. We studied this by coevolving the prey bacterium Serratia marcescens with the predatory protozoa Tetrahymena thermophila in constant and pulsed-resource environments for approximately 1300 prey generations. Consistent with arms race theory, the prey evolved to be more defended, whereas the predator evolved to be more efficient in consuming the bacteria. Coevolutionary adaptations were costly in terms of reduced prey growth in resource-limited conditions and less efficient predator growth on nonliving resource medium. However, no differences in mean coevolutionary changes or adaptive costs were observed between environments, even though resource pulses increased fluctuations and mean densities of coevolving predator populations. Interestingly, a surface-associated prey defence mechanism (bacterial biofilm), to which predators were probably unable to counter-adapt, evolved to be stronger in pulsed-resource environment. These results suggest that temporal resource fluctuations can increase the asymmetry of antagonistic coevolution by imposing stronger selection on one of the interacting species.


Subject(s)
Biological Evolution , Serratia marcescens/growth & development , Tetrahymena thermophila/pathogenicity , Adaptation, Physiological , Biofilms , Culture Media , Environment , Microbiological Techniques/methods , Serratia marcescens/physiology , Species Specificity , Tetrahymena thermophila/growth & development , Tetrahymena thermophila/physiology , Time Factors
6.
Resuscitation ; 63(3): 305-10, 2004 Dec.
Article in English | MEDLINE | ID: mdl-15582766

ABSTRACT

BACKGROUND: Survival improves in witnessed out-of-hospital cardiac arrest if the victim receives bystander-initiated cardiopulmonary resuscitation and rapid defibrillation (BLS/AED). The European Resuscitation Council has a simple programme to teach these life-saving skills that require no previous experience of automated external defibrillators (AEDs). To be able to implement the use of AEDs widely, many instructors are needed, and therefore, lay persons may also be used as trainers. The purpose of this randomized study was to compare lay volunteers trained by a lay person with those trained by a health care professional using the Objective Structured Clinical Examination (OSCE). METHODS: Eight instructors, including four lay persons and four health care professionals, were given a basic course and an instructor course in CPR-D by the same instructor. All newly trained instructors trained 38 lay volunteers (19 pairs) who had no previous training in the use of a defibrillator. The lay volunteers performed the OSCE 2-3 weeks after the course. The OSCE comprised two scenarios with a manikin: the first, a patient in cardiac arrest with ventricular fibrillation, and the second, an imminent cardiac arrest with asystole as the initial rhythm. The same OSCE was performed by a group of lay first aiders practicing every 2 weeks who served as the control group. RESULTS: No statistical difference was present between the two groups of lay volunteers in the OSCE. All were able to use the AED and follow instructions. They identified patients with ventricular fibrillation and cardiac arrest, but had difficulties identifying cases with imminent cardiac arrest. The control group of trained first aiders performed significantly more effectively than the newly trained lay persons. CONCLUSIONS: No significant benefit exists in the trainer being a health care professional, but thorough training and subsequent rehearsing of the skills learned are crucial.


Subject(s)
Cardiopulmonary Resuscitation/education , Cardiopulmonary Resuscitation/instrumentation , Electric Countershock , Health Education , Volunteers/education , Health Personnel/education , Humans , Teaching
7.
Appl Radiat Isot ; 61(5): 975-9, 2004 Nov.
Article in English | MEDLINE | ID: mdl-15308178

ABSTRACT

Boron biodistribution after intravenous infusion of 4-dihydroxyborylphenylalanine-fructose (BPA-F) complex was investigated in six dogs. Blood samples were evaluated during and following doses of 205 and 250 mg/kgbw BPA in a 30 min infusion, and 500 mg/kgbw in a 1h infusion. Samples from whole blood, urine, brain and other organs were analysed for boron content after varying times following the onset of infusion. The whole blood boron concentrations declined from 27 to 8.4 ppm over the period of 39-165 min after the onset of infusion and the levels increased from 1.9 to 12 ppm in the grey matter of the brain over the same period. The boron concentrations in whole blood decreased steadily, whereas the boron values in brain tissue rose steadily with time. It was concluded that whole blood boron concentrations do not seem to reflect accurately the boron concentration in brain tissue at respective time points.


Subject(s)
Boron Compounds/administration & dosage , Boron/pharmacokinetics , Fructose/analogs & derivatives , Fructose/administration & dosage , Animals , Boron/blood , Boron Compounds/blood , Boron Compounds/pharmacokinetics , Boron Neutron Capture Therapy , Brain/metabolism , Dogs , Fructose/blood , Fructose/pharmacokinetics , Infusions, Intravenous , Tissue Distribution
8.
Resuscitation ; 61(2): 149-53, 2004 May.
Article in English | MEDLINE | ID: mdl-15135191

ABSTRACT

Tracheal intubation (ETI) is considered the method of choice for securing the airway and for providing effective ventilation during cardiac arrest. However, ETI requires skills which are difficult to maintain especially if practised infrequently. The laryngeal tube (LT) has been successfully tested and used in anaesthesia and in simulated cardiac arrest in manikins. To compare the initiation and success of ventilation with the LT, ETI and bag-valve mask (BVM) in a cardiac arrest scenario, 60 fire-fighter emergency medical technician (EMT) students formed teams of two rescuers at random and were allocated to use these devices. We found that the teams using the LT were able to initiate ventilation more rapidly than those performing ETI (P < 0.0001). The LT and ETI provided equal minute volumes of ventilation, which was significantly higher than that delivered with the BVM (P < 0.0001). Our data suggest that the LT may enable airway control more rapidly and as effectively as ETI, and compared to BVM, may provide better minute ventilation when used by inexperienced personnel.


Subject(s)
Cardiopulmonary Resuscitation/methods , Clinical Competence , Intubation, Intratracheal , Laryngeal Masks , Adult , Airway Resistance , Education, Professional , Emergency Medical Services , Emergency Medical Technicians/education , Female , Finland , Heart Arrest/therapy , Humans , Male , Probability , Quality Control , Respiration, Artificial/methods
9.
Eur J Clin Invest ; 32(11): 795-802, 2002 Nov.
Article in English | MEDLINE | ID: mdl-12423319

ABSTRACT

BACKGROUND: Impairment of coronary blood flow reserve has been shown to be an early manifestation of atherosclerosis and coronary artery disease (CAD). We studied more closely the contribution of various risk factors on early deterioration of coronary function. MATERIALS AND METHODS: Fifty-one young, apparently healthy adults, with normal or mildly elevated serum cholesterol levels but without other major risk factors for CAD, such as diabetes or hypertension, underwent positron emission tomography (PET) studies. Coronary flow reserve (CFR) was measured using O15-water. In addition to the classical risk factors, the role of several new risk indicators, such as low-density lipoprotein (LDL) oxidation, infection (Chlamydia pneumoniae antibodies), and inflammation parameters (adhesion molecules, ICAM, VCAM, selectin, and C-reactive protein), homocysteine and body iron stores were investigated. RESULTS: Elevated lipid and lipoprotein levels were not associated with reduced coronary reactivity. However, high autoantibody titers against oxidized LDL (oxLDL) were associated with 21% lower CFR than low oxLDL (P < 0.05). Furthermore, high homocysteine levels predicted low CFR (P < 0.05). The other measured parameters, Chlamydia pneumoniae antibody levels, C-reactive protein and adhesion molecule concentrations did not associate with myocardial blood flow. In a stepwise regression model, oxLDL (P = 0.03), homocysteine (P = 0.04) and triglycerides (P = 0.018) were significant predictors of CFR. CONCLUSIONS: The present study suggests an important role for oxidized LDL and plasma homocysteine on early impairment of coronary reactivity in young adults.


Subject(s)
Coronary Circulation , Coronary Disease/physiopathology , Homocysteine/blood , Lipoproteins, LDL/blood , Adenosine , Adult , Autoantibodies/blood , Biomarkers/blood , C-Reactive Protein/analysis , Cell Adhesion Molecules/analysis , Chlamydophila Infections/blood , Chlamydophila Infections/complications , Chlamydophila Infections/diagnostic imaging , Chlamydophila pneumoniae , Cholesterol/blood , Cholesterol, HDL/blood , Coronary Disease/blood , Coronary Disease/diagnostic imaging , Ferritins/blood , Humans , Image Processing, Computer-Assisted , Linear Models , Lipoproteins, LDL/immunology , Male , Regional Blood Flow , Risk Factors , Smoking , Tomography, Emission-Computed , Triglycerides/blood
10.
Eur J Clin Invest ; 32(6): 400-4, 2002 Jun.
Article in English | MEDLINE | ID: mdl-12059984

ABSTRACT

BACKGROUND: Oxidised low-density lipoprotein (ox-LDL) is a determinant of impaired coronary function and oestrogens inhibit its formation probably throughout genetically-variable oestrogen receptor 1 (ESR1) in artery wall. We hypothesized that the ESR1 polymorphism might influence coronary function and reactivity as measured by positron emission tomography (PET), which allows the detection of coronary dysfunction before appearance of angiographic lesions. MATERIALS AND METHODS: Fifty-one healthy young men (aged 35 +/- 4 years), with normal or slightly-elevated serum cholesterol, underwent PET with intravenous adenosine. ESR1 PvuII genotypes P/P, P/p, and p/p in addition to the plasma autoantibody titre against ox-LDL, a marker of in vivo oxidation, were determined. RESULTS: The ESR1 genotype persisted as the only significant predictor of adenosine stimulated coronary flow (P = 0.035) after adjustment for other coronary risk factors. Subjects with P/P genotype had 33.4 and 41.8% lower adenosine-stimulated flow values than subjects with P/p and p/p genotypes (P = 0.030). Furthermore, plasma levels of ox-LDL titre were on average 59 and 77% higher in subjects with P/P genotype than in subjects with P/p or p/p genotypes (P = 0.049). CONCLUSIONS: These tentative findings from our pilot study provide evidence that genetic variation in ESR1 may modify coronary reactivity and LDL oxidation and reflect differences in the early pathogenesis of coronary dysfunction in these healthy young men.


Subject(s)
Cardiovascular Physiological Phenomena , Genetic Variation , Receptors, Estrogen/genetics , Adult , Blood Pressure , Cholesterol/blood , Coronary Circulation/physiology , Estrogen Receptor alpha , Genotype , Humans , Lipoproteins/blood , Male , Oxidation-Reduction , Polymorphism, Genetic , Tomography, Emission-Computed , Triglycerides/blood
11.
Stud Health Technol Inform ; 84(Pt 1): 489-92, 2001.
Article in English | MEDLINE | ID: mdl-11604788

ABSTRACT

The present aim was to explore the possibilities of using neural networks for recognizing significant changes in electrical activity of human facial muscles. We used multilayer perceptron neural networks to recognize bursts of electromyographic signals recorded with bipolar surface electrodes from two subject's facial muscles. Wavelets were applied for the detection of high frequency components of electromyographic signals. Coefficients of wavelets were used as an input to a neural network in order to differentiate bursts from the signals. The results showed that the recognition of bursts was very successful resulting to 84-97 percent total accuracies. The results were very encouraging and suggest further that the measurement of facial muscle activity may be a potentially useful computer input signal, for example, for affective computing which can be seen as a future versatile interaction between the computer and the user.


Subject(s)
Electromyography , Facial Muscles/physiology , Neural Networks, Computer , Electrophysiology , Humans , Pattern Recognition, Automated
12.
Acta Otolaryngol Suppl ; 545: 53-6, 2001.
Article in English | MEDLINE | ID: mdl-11677742

ABSTRACT

We studied the use of virtual reality technology as a stimulus in balance examinations. A pilot study was made using a small group of healthy subjects to investigate the effect of alcohol and virtual reality stimulus on the subjects' balance. The tests showed that blood alcohol concentration accounted for almost 50% of the increased lateral body sway velocity. The new stimulus technique based on virtual reality technology seems to be effective and flexible for postural investigations.


Subject(s)
Posture , User-Computer Interface , Adult , Double-Blind Method , Ethanol/blood , Ethanol/pharmacology , Feedback , Head/physiology , Humans , Male , Movement/drug effects , Movement/physiology , Nonlinear Dynamics , Pilot Projects , Visual Perception/drug effects
13.
Clin Chem ; 47(10): 1796-803, 2001 Oct.
Article in English | MEDLINE | ID: mdl-11568089

ABSTRACT

BACKGROUND: Boron neutron-capture therapy (BNCT) is a drug-targeted binary radiotherapy for cancer. The (10)B capture of thermal neutrons induces secondary radiation within cells during irradiation. The most widely used boron carrier is 4-dihydroxyborylphenylalanine (BPA). The duration and timing of the irradiation is adjusted by monitoring (10)B concentrations in whole blood. METHODS: We developed a new method for boron determination that uses inductively coupled plasma atomic emission spectrometry (ICP-AES) and protein removal with trichloroacetic acid before analysis. This method was compared with the established but tedious inductively coupled plasma mass spectrometry (ICP-MS), which uses wet ashing as sample pretreatment. Erythrocyte boron concentrations were determined indirectly on the basis of plasma and whole blood boron concentrations and the hematocrit. The hematocrit was determined indirectly by measuring calcium concentrations in plasma and whole blood. RESULTS: Within- and between-day CVs were <5%. The recoveries for boron in whole blood were 95.6-96.2%. A strong correlation was found between results of the ICP-AES and ICP-MS (r = 0.994). Marked differences in plasma and erythrocyte boron concentrations were observed during and after infusion of BPA fructose complex. CONCLUSIONS: The present method is feasible, accurate, and one of the fastest for boron determination during BNCT. Our results indicate that it is preferable to determine boron in plasma and in whole blood. Indirect erythrocyte-boron determination thus becomes possible and avoids the impact of preanalytical confounding factors, such as the influence of the hematocrit of the patient. Such an approach enables a more reliable estimation of the irradiation dose.


Subject(s)
Boron Neutron Capture Therapy , Boron/blood , Adult , Aged , Boron Compounds , Female , Hematocrit , Humans , Indicators and Reagents , Male , Mass Spectrometry/methods , Middle Aged , Phenylalanine/analogs & derivatives , Sensitivity and Specificity , Spectrophotometry, Atomic
14.
J Mol Med (Berl) ; 79(8): 449-58, 2001 Aug.
Article in English | MEDLINE | ID: mdl-11511975

ABSTRACT

This study examined the relationships between paraoxonase genotypes, coronary artery reactivity, and indices of low-density lipoprotein oxidation in healthy men. Impairment in coronary flow reserve, as assessed by positron emission tomography, is associated with lipoprotein oxidation, which is affected by high-density lipoprotein bound enzyme, paraoxonase. Paraoxonase has two common polymorphisms (M/L55 and R/Q192) that change the activity of the enzyme. Forty-nine healthy men (mean age 35 +/- 4 years) were divided by paraoxonase genotype into low (Q192/Q192, or M55/M55, M55/L55) and high-active (R192/Q192, R192/R192, or L55/L55) groups and related to the myocardial blood flow, to the susceptibility of low-density lipoprotein to oxidation, and the autoantibody titer against oxidized low-density lipoprotein. The blood flow was measured by positron emission tomography at rest and during adenosine infusion. The low-active Q192/Q192 genotype was associated with higher resting blood flow corrected for rate-pressure product compared to the high-active R192/R192 and R192/Q192 genotypes (P=0.011). The blood flow stimulated by adenosine was not significantly different in the low- and high-active genotype groups. Paraoxonase genotypes had no effect on low-density lipoprotein susceptibility to oxidation or autoantibody formation against oxidized low-density lipoprotein. Genotypes of paraoxonase may not clearly contribute to the early changes in coronary reactivity. Coronary vasomotor tone at rest appears to be modulated by paraoxonase R/Q192 polymorphism through mechanism(s) unrelated to low-density lipoprotein oxidation.


Subject(s)
Coronary Disease/genetics , Esterases/genetics , Genetic Predisposition to Disease/genetics , Polymorphism, Genetic , Adult , Arteriosclerosis/blood , Arteriosclerosis/enzymology , Arteriosclerosis/genetics , Arteriosclerosis/physiopathology , Aryldialkylphosphatase , Blood Flow Velocity/genetics , Blood Pressure/genetics , Body Mass Index , Cholesterol/blood , Cholesterol, HDL/blood , Cholesterol, HDL/metabolism , Coronary Circulation/genetics , Coronary Disease/blood , Coronary Disease/enzymology , Coronary Disease/physiopathology , Coronary Vessels/enzymology , Coronary Vessels/physiology , Esterases/metabolism , Genotype , Heart Rate/genetics , Humans , Lipoproteins, LDL/blood , Lipoproteins, LDL/metabolism , Male , Oxidation-Reduction , Tomography, Emission-Computed , Triglycerides/blood
15.
Lancet ; 358(9299): 2127-8, 2001.
Article in English | MEDLINE | ID: mdl-11784629

ABSTRACT

Asymmetrical dimethylarginine (ADMA) is an endogenous nitric oxide synthase inhibitor, which has been suggested to be a novel independent risk factor for endothelial dysfunction and coronary heart disease. We investigated the association of ADMA concentration in serum with risk of acute coronary events. We did a prospective, nested, case-control study in middle-aged men from eastern Finland. In an analysis of men who did not smoke, those who were in the highest quartile for ADMA (>0.62 micromol/L) had a 3.9-fold (95% CI 1.25-12.3, p=0.02) increase in risk of acute coronary events compared with the other quartiles. Our findings suggest that ADMA is a predictor of acute coronary events.


Subject(s)
Arginine/blood , Coronary Disease/blood , Endothelium, Vascular/physiopathology , Humans , Male , Middle Aged , Risk Assessment
16.
Kidney Int ; 58(6): 2462-72, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11115079

ABSTRACT

BACKGROUND: Cyclosporine A (CsA)-induced hypertension and nephrotoxicity are aggravated by high sodium intake. Accumulating evidence suggests that potassium and magnesium supplementation could protect against the detrimental effects of dietary salt. In the present study, we tested the hypothesis of whether concurrent supplementation with potassium and magnesium could protect against the development of CsA-induced hypertension and nephrotoxicity more effectively than supplementation with one mineral alone. METHODS: Eight-week-old spontaneously hypertensive rats (SHRs) were divided into four groups (N = 10 in each group): (1) CsA group (5 mg/kg subcutaneously) receiving high-sodium diet (Na 2.6%, K 0.8%, Mg 0.2% wt/wt); (2) CsA group receiving a high-sodium, high-potassium diet (Na 2.6%, K 2.4%, Mg 0.2%); (3) CsA group receiving high-sodium, high-magnesium diet (Na 2.6%, K 0.8%, Mg 0.6%); and (4) CsA group receiving high-sodium, high-potassium, high-magnesium diet (Na 2.6%, K 2.4%, Mg 0.6%). RESULTS: CsA induced severe hypertension and deteriorated renal functions in SHRs on high-sodium diet. Histologically, the kidneys showed severe thickening of the media of the afferent artery with fibrinoid necrosis. Potassium supplementation lowered blood pressure (198 +/- 5 vs. 212 +/- 2 mm Hg, P < 0.05) and partially prevented the development of proteinuria (-25%, P < 0.05). Magnesium supplementation decreased blood pressure to the same extent but improved renal functions more effectively than potassium. The greatest protection against CsA toxicity was achieved when dietary potassium and magnesium supplementations were combined. Urinary N-acetyl-beta-D-glucosaminidase (NAG) excretion, a marker for renal proximal tubular damage, increased progressively in CsA-treated SHRs on the high-sodium diet. Neither potassium nor magnesium influenced urinary NAG excretion. We also estimated the activity of the renal dopaminergic system by measuring 24-hour urinary dopamine excretion rates. CsA suppressed the renal dopaminergic system during high-sodium diet. Magnesium supplementation, alone and in combination with potassium, protected against the development of renal dopaminergic deficiency in CsA-treated SHRs on high-sodium diet. Magnesium supplementation increased plasma-free ionized magnesium (iMg) and bone magnesium by 50 and 16%, respectively. CONCLUSIONS: Our findings indicate that both potassium and magnesium supplementations showed beneficial effects against CsA-induced hypertension and nephrotoxicity. The protective effect of magnesium clearly exceeded that of potassium. The greatest protection against CsA toxicity was achieved when potassium and magnesium were combined. We also provide evidence that the development of CsA-induced glomerular, tubular, and vascular lesions are associated with renal dopaminergic deficiency.


Subject(s)
Cyclosporine/toxicity , Hypertension, Renal/chemically induced , Hypertension, Renal/drug therapy , Immunosuppressive Agents/toxicity , Magnesium/pharmacology , Potassium, Dietary/pharmacology , Acetylglucosaminidase/urine , Animals , Blood Pressure , Bone and Bones/chemistry , Cholesterol/blood , Cyclosporine/blood , Cyclosporine/pharmacokinetics , Dopamine/physiology , Heart Rate , Hypertension, Renal/pathology , Hypertrophy, Left Ventricular/chemically induced , Hypertrophy, Left Ventricular/drug therapy , Hypertrophy, Left Ventricular/pathology , Immunosuppressive Agents/blood , Immunosuppressive Agents/pharmacokinetics , Kidney Failure, Chronic/chemically induced , Kidney Failure, Chronic/drug therapy , Kidney Failure, Chronic/pathology , Kidney Tubules, Proximal/chemistry , Kidney Tubules, Proximal/pathology , Magnesium/analysis , Male , Myocardium/chemistry , Norepinephrine/urine , Proteinuria/chemically induced , Proteinuria/drug therapy , Proteinuria/pathology , Rats , Rats, Inbred SHR , Rats, Inbred WKY , Sodium, Dietary/pharmacology , Tissue Distribution
17.
J Theor Biol ; 207(3): 377-87, 2000 Dec 07.
Article in English | MEDLINE | ID: mdl-11082307

ABSTRACT

In this paper, we examine the effects of patch number and different dispersal patterns on dynamics of local populations and on the level of synchrony between them. Local population renewal is governed by the Ricker model and we also consider asymmetrical dispersal as well as the presence of environmental heterogeneity. Our results show that both population dynamics and the level of synchrony differ markedly between two and a larger number of local populations. For two patches different dispersal rules give very versatile dynamics. However, for a larger number of local populations the dynamics are similar irrespective of the dispersal rule. For example, for the parameter values yielding stable or periodic dynamics in a single population, the dynamics do not change when the patches are coupled with dispersal. High intensity of dispersal does not guarantee synchrony between local populations. The level of synchrony depends also on dispersal rule, the number of local populations, and the intrinsic rate of increase. In our study, the effects of density-independent and density-dependent dispersal rules do not show any consistent difference. The results call for caution when drawing general conclusions from models of only two interacting populations and question the applicability of a large number of theoretical papers dealing with two local populations.


Subject(s)
Models, Biological , Population Dynamics , Animals , Population Density
18.
Proc Biol Sci ; 267(1455): 1851-6, 2000 Sep 22.
Article in English | MEDLINE | ID: mdl-11052535

ABSTRACT

Characterizing population fluctuations and their causes is a major theme in population ecology. The debate is on the relative merits of density-dependent and density-independent effects. One paradigm (revived by the research on global warming and its relation to long-term population data) states that fluctuations in population densities can often be accounted for by external noise. Several empirical models have been suggested to support this view. We followed this by assuming a given population skeleton dynamics (Ricker dynamics and second-order autoregressive dynamics) topped off with noise composed of low- and high-frequency components. Our aim was to determine to what extent the modulated population dynamics correlate with the noise signal. High correlations (with time-lag -1) were observed with both model categories in the region of stable dynamics, but not in the region of periodic or complex dynamics. This finding is not very sensitive to low-frequency noise. High correlations throughout the entire range of dynamics are only achievable when the impact of the noise is very high. Fitted parameter values of skeleton dynamics modulated with noise are prone to err substantially. This casts doubt as to what degree the underlying dynamics are any more recognizable after being modulated by the external noise.


Subject(s)
Ecosystem , Environment , Animals , Mathematics , Models, Biological , Population Density , Population Dynamics
19.
Nutr Metab Cardiovasc Dis ; 10(3): 126-36, 2000 Jun.
Article in English | MEDLINE | ID: mdl-11006921

ABSTRACT

BACKGROUND AND AIM: Oxidized LDL has been detected in atherosclerotic vessels and presumed to be one of the major risk factors in atherosclerosis and cardiovascular diseases. The aims of the present study were to clarify whether the oxidation degree of LDL influences arterial tone and whether different long-lasting dietary habits have effects on biological variables. METHODS AND RESULTS: The lag phase of LDL oxidation was shorter (117 +/- 6 min) in the fish diet group than in the vegetarian (153 +/- 5 min) or the control diet group (152 +/- 10 min). The rat mesenteric arterial rings, which were preincubated with LDL oxidized to 1-30%, from the vegetarian and the fish diet groups showed (p < 0.05) decreased NA-induced maximal contraction forces when compared to the control diet. The LDL oxidation degrees of 31-60% and 61-90% had no effect on NA- and KCl-induced maximal contraction forces when compared to native LDL, nor were there differences between the diet groups. Endothelium-dependent and independent relaxation responses behaved similarly in all groups and were independent of the degree of oxidation. CONCLUSIONS: Dietary habits change the fatty acid composition of LDL, but have only minor effects on the vasoactive properties of oxidized LDL.


Subject(s)
Arteriosclerosis/diet therapy , Cardiovascular Diseases/diet therapy , Dietary Fats/administration & dosage , Feeding Behavior , Lipoproteins, LDL/metabolism , Muscle, Smooth, Vascular/drug effects , Adult , Animals , Antioxidants/analysis , Arteriosclerosis/prevention & control , Biological Assay , Cardiovascular Diseases/prevention & control , Diet, Vegetarian , Fatty Acids/analysis , Fishes , Humans , Lipid Peroxidation , Lipids/blood , Lipoproteins, LDL/blood , Lipoproteins, LDL/chemistry , Male , Middle Aged , Muscle, Smooth, Vascular/metabolism , Oxidation-Reduction , Rats , Rats, Wistar , Vasoconstriction
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