RESUMO
BACKGROUND: The internet is widely and increasingly used to search for health information. Previous studies have focused mainly on health information on the internet and not specifically on medicines information (MI). OBJECTIVES: The aim of this study was to explore the internet as a source of MI compared to other sources of MI; to identify those who use the internet as a source of MI; and to describe patterns of use of the internet as a source of MI. METHODS: A cross-sectional design employed a web-based questionnaire posted by patients' and other organizations as well as pharmacies on their websites during six weeks in the beginning of 2014. Logistic regression analysis was used to assess associations of background variables to the use of different MI sources. RESULTS: The most frequently used MI sources among respondents (n = 2489) were package leaflets (90%), pharmacists (83%), physicians (72%), and the internet (68%). According to a multivariate analysis, internet use for MI was associated with female gender, age <65 years, higher education, daily use of the internet, and continuous use of vitamins or herbals. MI was most commonly searched from a Finnish health portal (56%) and websites of pharmacies (41%). Of the respondents, nearly half (43%) used search engines to find information from the internet. The names of the medicinal product, symptom or disease were the most commonly used search terms. CONCLUSIONS: Well-educated, young women tend to search MI on the internet. Health care professionals should discuss reliable MI websites and tools that can help patients evaluate the reliability of information.
Assuntos
Informação de Saúde ao Consumidor , Serviços de Informação sobre Medicamentos/estatística & dados numéricos , Internet/estatística & dados numéricos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Rotulagem de Medicamentos , Feminino , Finlândia , Humanos , Disseminação de Informação , Comportamento de Busca de Informação , Masculino , Pessoa de Meia-Idade , Farmacêuticos , Médicos , Inquéritos e Questionários , Adulto JovemRESUMO
Although athletes' beliefs and values are known to influence whether or not an athlete will use banned drugs, little is known about the athletes' beliefs and attitudes in different sports. The aim of this study was to clarify the beliefs and attitudes of elite athletes towards banned substances and methods in sports. A total of 446 athletes (response rate 90.3 %; 446/494) financially supported by the National Finnish Olympic Committee completed a structured questionnaire during their national team camps in 2002. More than 90 % of the athletes reported to believe that banned substances and methods have performance enhancing effects, and 30 % reported that they personally know an athlete who uses banned substances. Of the male athletes 35 %, and 23 % of females reported they personally know an athlete using banned substances. A total of 15 % of the athletes reported that they had been offered banned substances: 21 % of the speed and power athletes, 14 % of the team sport athletes and of the athletes in motor skills demanding events, and 10 % of the endurance athletes. Stimulants were the most often offered substance group (to 7 % of all the athletes) followed by anabolic steroids (4 %). Subjects who regarded doping as a minor health risk seemed to be more often associated with doping users than those regarding doping as a significant health risk. Athletes in different sports have a different approach to doping. Risk of doping appears to be highest in speed and power sports and lowest in motor skills demanding sports. Males are at higher risk than females. Controlling doping only by tests is not sufficient. A profound change in the attitudes is needed, which should be monitored repeatedly.
Assuntos
Atitude , Dopagem Esportivo/psicologia , Esportes/psicologia , Adulto , Distribuição de Qui-Quadrado , Estudos Transversais , Feminino , Humanos , Masculino , Inquéritos e QuestionáriosAssuntos
Assistência Ambulatorial/economia , Trombose Venosa/economia , Adulto , Idoso , Idoso de 80 Anos ou mais , Redução de Custos , Análise Custo-Benefício , Feminino , Hospitalização , Humanos , Masculino , Pessoa de Meia-Idade , Embolia Pulmonar/etiologia , Trombose Venosa/complicações , Trombose Venosa/terapiaRESUMO
Nicotine was administered chronically to NMRI mice in their drinking water in gradually increasing concentrations to measure gross motor activity and brain nicotine concentrations over 24 h on the 50th day of nicotine administration. Also, the striatal postmortem tissue concentrations and accumbal extracellular concentrations of dopamine (DA) and its metabolites 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) were measured to study the role of dopaminergic systems in nicotine-induced hyperactivity in mice. The cerebral nicotine concentration was at its highest at the end of the dark period. The activity of nicotine-treated mice and their striatal DA metabolism were parallelly increased at 2 to 3 h after midnight and in the forenoon. Microdialysis experiments carried out in the forenoon showed that the extracellular levels of DA and DOPAC were elevated in the nucleus accumbens of these mice. Nicotine did not alter the circadian rhythmicity of activity in the mice. Rather, our findings suggest that the mice consume more nicotine when active and this might lead to enhanced release and metabolism of DA and further, to enhanced motor behavior. These findings support the suggestions that nicotine's effects on limbic and striatal DA are critical for its stimulating effects.
Assuntos
Encéfalo/efeitos dos fármacos , Dopamina/metabolismo , Atividade Motora/efeitos dos fármacos , Nicotina/administração & dosagem , Agonistas Nicotínicos/administração & dosagem , Água/administração & dosagem , Animais , Encéfalo/metabolismo , Ingestão de Líquidos , Masculino , Camundongos , Atividade Motora/fisiologiaAssuntos
Dor no Peito/diagnóstico , Dispneia/diagnóstico , Pneumotórax/diagnóstico , Idoso , Idoso de 80 Anos ou mais , Dor no Peito/etiologia , Diagnóstico Diferencial , Dispneia/etiologia , Eletrocardiografia , Feminino , Humanos , Infarto do Miocárdio/diagnóstico , Pneumotórax/complicações , Pneumotórax/terapiaRESUMO
The effects of chronic nicotine and its withdrawal on locomotor activity and brain monoamines were studied using a new animal model of administering nicotine in the drinking water to male NMRI mice as the sole source of fluid. Locomotor activity as well as cerebral concentrations of dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), 5-hydroxytryptamine (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), noradrenaline (NA) and 3-methoxy-4-hydroxyphenylethyleneglycol (MOPEG) were measured post mortem on the 50th day of nicotine administration or at 12-14 or 23-25 h after withdrawal. On the 50th day of drug administration the chronically nicotine-treated mice were more active than the control mice drinking tap water and after withdrawal from nicotine the locomotor activity dropped to the level of the controls. In chronically nicotine-treated mice the striatal concentrations of DOPAC, HVA and 5-HIAA, hypothalamic 5-HIAA and NA as well as cortical NA were elevated. The concentrations of DOPAC, HVA and 5-HIAA reversed to control levels within 23-25 h after withdrawal from nicotine. The nicotine-induced elevation of the hypothalamic NA concentration was still significant at 23-25 h after withdrawal. At 12-14 h after withdrawal the hypothalamic concentration of MOPEG was increased. In conclusion, our findings on locomotor activity suggest that administration of nicotine in the drinking water to mice for several weeks seems to be a relevant method to study nicotine dependence. Furthermore, the alterations found in cerebral DA, NA and 5-HT metabolism during chronic nicotine administration indicate that all three cerebral transmitter monoamines might be involved in nicotine dependence and withdrawal.
Assuntos
Encéfalo/efeitos dos fármacos , Atividade Motora/efeitos dos fármacos , Neurotransmissores/metabolismo , Nicotina/toxicidade , Síndrome de Abstinência a Substâncias/fisiopatologia , Tabagismo/fisiopatologia , Animais , Encéfalo/fisiopatologia , Mapeamento Encefálico , Modelos Animais de Doenças , Masculino , Camundongos , Camundongos Endogâmicos , Atividade Motora/fisiologiaRESUMO
Unilateral masticatory function was induced in 10-day-old rabbits by grinding the right side molars out of occlusion under general anesthesia. The grinding procedure was repeated twice a week thereafter. They were killed at the ages of 25 and 35 days. Rabbits of the same age with uninterfered occlusions served as controls. The changes in articular cartilage of the mandibular condyle were studied biochemically and histochemically. There was a significant decrease in the proteoglycan content of the condylar cartilage in both groups of animals subjected to molar grinding compared to the animals with untouched occlusions. Especially the amount of aggregating proteoglycans was reduced. The condylar cartilage matrix synthesis is sensitive to loading produced by masticatory function during growth. The mechanical properties of the articular cartilage after a period of unilateral mastication will be impaired and it is possible that this makes the joint cartilage more susceptible to pathological events.
Assuntos
Cartilagem Articular/metabolismo , Côndilo Mandibular/fisiopatologia , Mastigação/fisiologia , Proteoglicanas/análise , Adaptação Fisiológica , Animais , Côndilo Mandibular/crescimento & desenvolvimento , Dente Molar/fisiopatologia , CoelhosRESUMO
Although tobacco contains a large variety of substances, its addictive properties are most probably due to the reinforcing actions of nicotine that motivates continued tobacco use. Animals and humans self-administer nicotine, a response that appears to involve the mesolimbic dopamine system and to be common to other abused drugs. The present article reviews animal models to administer nicotine chronically. We also describe a new animal model in which nicotine is given to mice in drinking water as their sole source of fluid. This treatment produced nicotine plasma concentrations comparable to or above those found in smokers. We found that mice withdrawn from nicotine were tolerant to the effects of nicotine challenge on striatal dopamine metabolism as well as on body temperature and locomotor activity. Furthermore, 3H-nicotine binding in the cortex and midbrain was significantly increased in mice withdrawn from nicotine. The last part of the article will focus on the effects of this chronic nicotine treatment on striatal dopamine. Dopamine and its metabolites and locomotor activity were increased in the forenoon in mice still drinking nicotine solutions. We also report recent data in which chronic nicotine administration in the drinking water enhanced the effect of dopamine receptor agonist, quinpirole, on striatal metabolism. The animal model described appears to be a relevant method for studying the mechanisms that are thought to be involved in nicotine dependence.
Assuntos
Corpo Estriado/efeitos dos fármacos , Dopamina/metabolismo , Nicotina/toxicidade , Animais , Corpo Estriado/metabolismo , Ingestão de Líquidos , Tolerância a Medicamentos , Camundongos , Nicotina/administração & dosagem , Quimpirol/farmacologia , Tabagismo/etiologiaRESUMO
This paper reports the ergosterol content for microbial cultures of six filamentous fungi, three yeast species, and one actinomycete and the ergosterol levels in 40 samples of building materials (wood chip, gypsum board, and glass wool) contaminated by microorganisms. The samples were hydrolyzed in alkaline methanol, and sterols were silylated and analyzed by gas chromatography-mass spectrometry. The average ergosterol content varied widely among the fungal species over the range of 2.6 to 42 &mgr;g/ml of dry mass or 0.00011 to 17 pg/spore or cell. Ergosterol could not be detected in the actinomycete culture. The results for both the fungal cultures and building material samples supported the idea that the ergosterol content reflects the concentration of filamentous fungi but it underestimates the occurrence of yeast cells. The ergosterol content in building material samples ranged from 0.017 to 68 &mgr;g/g of dry mass of material. A good agreement between the ergosterol concentration and viable fungal concentrations was detected in the wood chip (r > 0.66, P = 0.009) and gypsum board samples (r > 0.48, P = 0.059), whereas no relationship between these factors was observed in the glass wool samples. For the pooled data of the building materials, the ergosterol content correlated significantly with the viable fungal levels (r > 0.63, P < 0.0001). In conclusion, the ergosterol concentration could be a suitable marker for estimation of fungal concentrations in contaminated building materials with certain reservations, including the underestimation of yeast concentrations.
Assuntos
Abandono do Hábito de Fumar/métodos , Fumar/tratamento farmacológico , Fumar/psicologia , Tabagismo/tratamento farmacológico , Atitude do Pessoal de Saúde , Humanos , Educação de Pacientes como Assunto , Farmácias , Fumar/efeitos adversos , Abandono do Hábito de Fumar/psicologia , Tabagismo/psicologiaRESUMO
In this study we compared the compositions of extracellular matrices of condylar, costal and nasal cartilages to characterize differences in growth patterns in relation to matrix composition. Condylar, costal and nasal cartilages of 25- and 35-day-old rabbits were extracted and subjected to bio- and histochemical analysis to determine total amounts of collagen and amounts and aggregating properties of proteoglycans. We found that proteoglycan content and aggregate formation were greatest in nasal cartilage, and lower in costal and markedly lower in condylar cartilage. The amount of proteoglycans increased by varying amounts in all samples with age. Collagen content was highest in costal cartilage. In 25-day-old rabbits the quantity of collagen in condylar cartilage exceeded that in nasal cartilage. In 35-day-old rabbits the quantities were nearly the same. It is suggested that collagen does not only provide tensile strength, but counteracts forces responsible for interstitial growth such as osmotic pressure. Based on the results, it seems that the amount of proteoglycans is greater in cartilages, which have greater independent growth potential. Variations in increase in amount of proteoglycans with age could reflect differences in the timing of growth of such cartilages.
Assuntos
Colágeno/metabolismo , Côndilo Mandibular/metabolismo , Septo Nasal/metabolismo , Proteoglicanas/metabolismo , Costelas/metabolismo , Animais , Coelhos , Fatores de TempoRESUMO
Fourteen Finnish 45,X/46,XX females were compared with population female and male controls, and in addition, nine of them were compared with their first-degree female relatives. Linear and angular measurements were made from standardized lateral cephalograms of patients and normal population controls from the "Kvantti" study series. In both comparisons the results indicated that craniofacial dimensions in 45,X/46,XX females were smaller than those in population female and male controls. The general metric pattern was similar to that observed in relation to the tooth crowns of 45,X/46,XX females. Several of their craniofacial proportions and plane angles differed from those of normal women: shorter anterior and posterior cranial bases and a flatter cranial-base angle, a sagittally shorter maxilla and a sagittally shorter mandible with an enlarged ramus:corpus length ratio, posterior rotation of the mandible and a tendency to bimaxillary retrusion. It is suggested that the reduction of X-chromosomal genetic material in 45,X/46,XX females results in smaller craniofacial dimensions than in normal females, with substantial effects on dimensional ratios and especially plane angles of the cranial base.
Assuntos
Anormalidades Craniofaciais/patologia , Aberrações dos Cromossomos Sexuais , Cromossomo X/genética , Adolescente , Adulto , Cefalometria , Anormalidades Craniofaciais/genética , Feminino , Humanos , Masculino , Mandíbula/patologia , Maxila/patologia , Crânio/patologiaRESUMO
The effect of nicotine withdrawal on regional regulation of brain nicotinic receptors was studied in mice after chronic administration of nicotine in the drinking water for 2, 4 or 7 weeks. Two weeks of chronic nicotine administration did not alter the binding of [3H]-nicotine in the midbrain, cortex or cerebellum of the mice, while after both 4-and 7-week treatments a significant increase in the specific [3H]-nicotine binding was observed in cortical and midbrain membranes. In the midbrain, the [3H]-nicotine binding was increased by about 40% in mice withdrawn for 48-72 h from the 4-week chronic nicotine treatment and in mice withdrawn for 48 h from the 7-week treatment. The [3H]-nicotine binding was significantly increased (by 55-65%) in the cortex at 48 h and 72 h after withdrawal from 4-week chronic nicotine and it was even somewhat more increased (by 72-66%) after 7-week treatment. The cortical [3H]-nicotine binding was not altered at 24 h after the 4-week treatment, but in mice withdrawn for 24 h from the 7-week treatment it was increased by 116%. The increases in [3H]-nicotine binding returned to control levels within 1 week after withdrawal. None of the studied treatments affected the [3H]-nicotine binding in the cerebellum. Tolerance towards nicotine-induced locomotor depression was only found in mice withdrawn for 24 h from the 7-week chronic nicotine administration. These findings suggest that at least 4-week chronic nicotine administration in the drinking water is needed before any upregulation of nicotinic receptors can be observed. Furthermore, in our experiments the increase in the [3H]-nicotine binding was seen before behavioural tolerance could be demonstrated. The differences between brain regions in the time course of nicotinic receptor upregulation may reflect variations in nicotinic receptor subunits and their sensitivity to chronic nicotine treatment.
Assuntos
Química Encefálica/efeitos dos fármacos , Nicotina/efeitos adversos , Agonistas Nicotínicos/efeitos adversos , Receptores Nicotínicos/metabolismo , Síndrome de Abstinência a Substâncias/metabolismo , Administração Oral , Animais , Cerebelo/efeitos dos fármacos , Cerebelo/metabolismo , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/metabolismo , Mesencéfalo/efeitos dos fármacos , Mesencéfalo/metabolismo , Camundongos , Atividade Motora/efeitos dos fármacos , Nicotina/administração & dosagem , Nicotina/metabolismo , Agonistas Nicotínicos/administração & dosagem , Agonistas Nicotínicos/metabolismo , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/fisiologiaRESUMO
Both the severe course of nephropathia epidemica (NE) caused by Puumala hantavirus, and the fast progression of human immunodeficiency virus (HIV) disease, are associated with the HLA B8 DRB1*0301 haplotype. As HLA B27, on the contrary, is associated with the slow progression of HIV disease, we wanted to test whether the same is true for NE. Only six (8%) NE patients, half the figure expected, had the HLA B27 allele in 74 randomly selected hospital-treated patients. All six had a benign overall clinical course of NE; none had any severe complications, the severity of renal failure was also mild, and the treatment time at the hospital was half that needed for HLA B27- patients (P = 0.004). Patients who were HLA B27 had maximal blood leucocyte count > 10.000 x 10(9)/L (P = 0.020) more often, probably reflecting differences in immune response. Thus, similar HLA associations can be found in both HIV infection and NE caused by Puumala virus.
Assuntos
Antígeno HLA-B27/imunologia , Infecções por Hantavirus/imunologia , Orthohantavírus , Adulto , Idoso , Feminino , Infecções por Hantavirus/virologia , Haplótipos , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
Peak serum C-reactive protein concentrations were measured in 146 patients randomized to receive streptokinase, alteplase, or a combination of streptokinase and alteplase in the GUSTO-I trial. Those receiving alteplase treatment had lower values than those receiving streptokinase or the combination treatment. Irrespective of treatment, complete reperfusion of the infarct-related artery (TIMI grade 3 flow) was associated with low peak serum C-reactive protein values.
Assuntos
Proteína C-Reativa/metabolismo , Hidroxibutirato Desidrogenase/sangue , Infarto do Miocárdio/sangue , Estreptoquinase/uso terapêutico , Ativador de Plasminogênio Tecidual/uso terapêutico , Idoso , Quimioterapia Combinada , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/tratamento farmacológicoRESUMO
The craniofacial cephalometric dimensions, angles and dimensional ratios of five Finnish individuals with complete testicular feminization (CTF) were compared with their first-degree relatives and population female and male controls. The linear and angular measurements were made from standardized lateral cephalograms of patients and normal population controls from the 'Kvantti Study' series. The women with CTF tended to have cranial base and maxillary complex dimensions between those of the normal control females and males. Their mandibular corpus was found to be longer than in normal control females, while their ramus was shorter compared with that of normal males. They also showed a smaller sagittal length ratio of the maxilla to the mandible, a smaller ANB angle and a more acute gonial angle than in both normal control females and males. Comparison of the women CTF with their first-degree female relatives showed basically the same trends as when comparing them with normal female controls. As the phenotype in these females with CTF is due to insensitivity to, or lack of androgens, it is suggested that the presence of the Y chromosome in these females leads to craniofacial dimensions between those of normal females and males which influences the growth of the mandibular corpus. This follows the same general metric pattern that is observed in many of their adult head and body dimensions as well as in their dental arches.
Assuntos
Síndrome de Resistência a Andrógenos/fisiopatologia , Desenvolvimento Maxilofacial , Adolescente , Adulto , Estudos de Casos e Controles , Cefalometria , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
Eight adult, Finnish 47,XYY males were compared with population male and female controls and, in addition, three of them were compared with first-degree male relatives. Linear and angular measurements were made from standardized lateral cephalograms of patients and normal population controls from the "Kvantti" study series. In both comparisons the craniofacial dimensions in 47,XYY males were larger than those in population male and female controls. Their craniofacial proportions and plane angles were similar to those of normal men except for a larger lower facial height with posterior rotation of the mandible and a tendency to bimaxillary protrusion, a longer cranial base and a lesser cranial-base angle. Thus the supernumerary Y chromosomal gene(s) in 47,XYY males may result in larger craniofacial dimensions than in normal males, without substantial effects on dimensional ratios and plane angles. This general metric pattern is similar to that observed in relation to many adult body and head dimensions, and the dental arches and tooth crowns, of 47,XYY males. The foramen magnum in 47,XYY males was smaller in the sagittal plane than that of normal males and females.
Assuntos
Face , Ossos Faciais/patologia , Crânio/patologia , Cariótipo XYY/patologia , Adolescente , Adulto , Antropometria , Cefalometria , Queixo/patologia , Arco Dental/patologia , Feminino , Finlândia , Forame Magno/patologia , Humanos , Masculino , Má Oclusão/patologia , Mandíbula/patologia , Maxila/patologia , Pessoa de Meia-Idade , Odontometria , Rotação , Sela Túrcica/patologia , Base do Crânio/patologia , Coroa do Dente/patologia , Cariótipo XYY/genética , Cromossomo YRESUMO
Information on coronary heart disease (CHD) obtained from the Finnish Hospital Discharge and Cause-of-Death Registers was compared with that collected in the Helsinki Heart Study (HHS) during an 8.5-year follow-up. The purpose of the comparison was two-fold, firstly, to study the accuracy of registration of CHD and secondly, to find out what diagnostic codes to use for CHD in register-based follow-up studies. The HHS cases were used as the 'golden standard' and the CHD deaths and definite nonfatal acute myocardial infarctions (AMIs) (all diagnoses) were taken from the registers to establish the sensitivity of the Hospital Discharge and Cause-of-Death Registers combined. The sensitivity was 0.84 during the period 1980-86 and 0.87 during 1987-90, with the positive predictive values 0.94 and 0.92 respectively. The treatment effects seen in the HHS were compared with the effects that would have emerged, if register-based information only had been used with different definitions of CHD. Of the register-based calculations, the one with the definition 'all CHD deaths and hospitalizations with the ICD-8 code 410' came closest to the HHS result, with a 32% reduction (P=0.028 one-sided) of CHD incidence, while the original HHS result was a 34% reduction (P=0.008 one sided). However, when comparing Kaplan-Meier plots of cumulative hazards of CHD, the plot with a wider definition of CHD (ICD-8 and ICD-9 codes 410-414) came closest to the HHS experience, especially if revascularizations were included in the latter. Definite AMI as a single definition of CHD might thus not be sufficient when studying CHD risk, instead, at least two parallel definitions of CHD should be used.
Assuntos
Doença das Coronárias/epidemiologia , Sistema de Registros , Doença das Coronárias/classificação , Doença das Coronárias/mortalidade , Finlândia/epidemiologia , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/epidemiologia , Sensibilidade e EspecificidadeRESUMO
After 7-week chronic administration of nicotine to mice in their drinking water, nicotine was withdrawn for 24 h. Acute nicotine challenge (1 mg/kg s.c., 60 min) elevated the striatal concentrations of dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) and decreased the concentration of 3-methoxytyramine significantly less in the mice withdrawn for 24 h from nicotine than in the control mice which had been drinking tap water under identical conditions for 7 weeks. Neither withdrawal nor the acute nicotine challenge altered the striatal dopamine concentration. No alterations were found in the density or affinity of the specific binding of [3H]SCH 23390 or [3H]spiperone to striatal membrane homogenates during nicotine treatment or after its withdrawal. Thus, our results show that tolerance to the acute effects of nicotine on striatal dopamine metabolism can be induced by administering nicotine to mice in the drinking water. However, neither chronic nicotine treatment nor its withdrawal seem to affect dopamine D1 and D2 receptors in the striatum.
Assuntos
Corpo Estriado/efeitos dos fármacos , Dopamina/metabolismo , Nicotina/farmacologia , Receptores Dopaminérgicos/efeitos dos fármacos , Animais , Temperatura Corporal/efeitos dos fármacos , Química Encefálica/efeitos dos fármacos , Corpo Estriado/química , Corpo Estriado/metabolismo , Tolerância a Medicamentos , Masculino , Camundongos , Camundongos Endogâmicos , Receptores de Dopamina D1/efeitos dos fármacos , Receptores de Dopamina D2/efeitos dos fármacosRESUMO
Until recently, only techniques for measuring total magnesium have been available. Now commercially available instruments using new ion-selective electrodes (ISE) for Mg+2 have made possible reliable measurement of ionized magnesium also in clinical practice. We measured changes induced by a hemodialysis session in serum ionized and total pools of magnesium and calcium using ISE methods. When compared with levels in age- and sex-matched control subjects, both serum ionized magnesium (0.68 +/- 0.11 vs. 0.56 +/- 0.06 mmol/l, p < 0.001) and total magnesium (1.00 +/- 0.19 vs. 0.82 +/- 0.08 mmol/l, p < 0.001) were higher in hemodialysis patients. The fraction of ionized Mg was 68.6 +/- 2.9% in hemodialysis patients, and did not differ significantly from that in controls (68.7 +/- 5.3%). The postdialysis value was 68.1 +/- 7.7%. The corresponding ratios of calcium (ionized/total) were 51.0 +/- 2.8% pre- and 50.9 +/- 4.6% postdialysis. Both prior to and after dialysis the correlation between ionized and total magnesium was high (r = 0.976, p < 0.001, and r = 0.925, p < 0.001, respectively). The corresponding ionized versus total calcium correlations were r = 0.724 (p < 0.001) before and 0.423 (p = 0.003) after dialysis. The changes induced by a hemodialysis session in serum concentration of ionized magnesium and calcium were dependent on the concentration of the cation in the dialysate. The change in PTH (suppression or stimulation) was very closely related to the changes in the serum concentration of ionized calcium. We concluded that measurement of ionized magnesium using ion-selective electrodes for Mg++ is an interesting new method in evaluating body magnesium status. Its definitive role in clinical practice cannot be judged on the basis of the results of the present study, but it will probably not achieve the same importance as the measurement of ionized calcium in clinical nephrology.