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PubMed1982

[Birth readiness of the uterine cervix. II. Cervix readiness score and its problems because of the variability of individual criteria].

Cervical ripeness was scored in nulliparous and parous women not in labor at term according to Bishop's pelvic score. The frequency distributions of the scores for the single criteria as well as of the total score reveal the problems of all those scoring systems caused by the grouping process as sequelae of the choice of width of the classes as well as of their limits. E.g. for cervical dilatation in none case 2 or 3 points had been reached and similar findings had to be stated concerning station of the presenting part. An other point of discussion erases from the results of the analysis for linear correlation of the single criteria between each other and between the single criteria and the total score. The total score is mostly influenced by the consistency (r = 0,81 in nulliparous and parous women) and the effacement (r = 0,80 and r = 0,81) of the cervix, whereas for dilatation and station lower correlation coefficients were found. In contrast, when labor had started spontaneously, even if the status of cervix was not advanced, a significant change in the correlative influence of the total score by the single criteria could be stated with high correlation coefficients for dilatation and station and lower one's for consistency and effacement.

Cervix Uteri↗
PubMed1976

[Individual anatomic variability of Forel's field H].

The investigation was performed in serial frontal sections of 100 preparations of the diencephalon and midbrain made 1 mm from one another. The shape of Forel H field was found to be very variable, changing from the rectangular to triangular shape in pararubralparts, and from oval to semioval-in prerubral parts. The size and position of Forel H field proved to change in relation to intracerebral reference points: posterior comissure, medial and intercomissural planes used in stereotaxical technique.

Adult↗
PubMed1996

[The influence of physical effort of variable intensity on glycemia in children with diabetes].

The influence of physical effort of variable intensity on glycaemia in children was analyzed in 61 children (29 girls and 32 boys) from 5-17 years of age with newly diagnosed diabetes and with diabetes lasting from 1-12 years (5.5 on average) was assessed. The children underwent an exercise test on a thread null. The pulse rate was on indicator of effort. Pulse rate before and after the effort was measured using a Sport-Tester apparatus and the level of glucose in the capillary bloodstream was determined using an Ames glucometer. Three tests of increasing intensity were performed, each lasting 20 minutes on three consecutive days. In children with well controlled insulin dependent diabetes with glycaemia up to 150 mg/100 ml in first three hours after test, physical effort of variable intensity caused an individually variable fall in glycaemia from 15-43 mg/100 ml. In children with poorly controlled insulin dependent diabetes with hyperglycaemia from 210 to 300 mg/100 ml, physical effort caused a rise of glycaemia from 20-80 mg/100 ml compared to controls. Up to 3 hours after physical effort, 20 children had hypoglycaemia 60 mg 100 ml and 4 children had hypoglycaemia below 40 mg/100 ml. Hypoglykaemia manifested as a mild complex of clinical signs.

Adolescent↗
PubMed2002

Learning and performance effects of accurate and erroneous knowledge of results on time perception.

Performance feedback (also known as knowledge of results or KR) has both performance and learning effects on many tasks. Earlier studies have demonstrated performance but not learning effects on time perception tasks. In this experiment, we dissociate and identify these two phenomena on two different time perception tasks. Participants were presented with either accurate (100%) or erroneous (80% or 120% of actual performance) KR on either a reproduction or a numerical estimation time perception task. Accurate (100%) KR reduced the group variability and increased the accuracy of response magnitude but left individual variability unchanged. Erroneous (80% or 120%) KR also reduced the group variability while leaving individual variation unchanged, but decreased the true accuracy of the response, with response magnitudes increasing for the 80% KR group and decreasing for the 120% group. Thus external KR that is in conflict with internal time cues overrides these internal cues and dictates response magnitude on these two tasks. Thus KR provides guidance for these behaviors. KR did not reduce the variability (dispersion) of participants' responses, but centered each participant's responses closer to the targeted performance. This decreased group response variability reflected a performance enhancing effect of KR because group response variability increased after KR was withdrawn. In contrast, response magnitudes remained changed for the duration of the post-KR period, indicating that KR also induced a learned response. Thus individual response variability, group response variability and response magnitude represent dissociable features of performance on these time perception tasks.

Adult↗
PubMed1988

Alcohol consumption, age and personality characteristics as important determinants of within-subject variability in blood pressure.

Intra-individual variability in blood pressure is well recognized but its determinants have been largely unexplored. In a recent cross-sectional study, 343 subjects from a male working population were assessed. Ten supine blood pressure readings were taken at 2-min intervals for 20 min on each of three consecutive days. Each subject's body mass index (weight/height2) was recorded and a questionnaire completed to record demographic details and information about physical activity, personality characteristics, dietary habits, tea and coffee consumption, smoking habits and alcohol consumption. When systolic and diastolic blood pressure variability was defined as the average coefficient of variation of the 10 readings each day, systolic blood pressure variability was found to be positively correlated with alcohol consumption, verbal aggression score and extroversion score. Diastolic variability was positively correlated with verbal aggression score, type-A personality score and extroversion score, and negatively associated with age. Stepwise regression analysis revealed alcohol consumption to be the strongest determinant of systolic variability while age was the strongest determinant of diastolic variability. We conclude that alcohol consumption, age and personality characteristics may be important determinants of intra-subject variability in blood pressure.

Adult↗
PubMed2001

Pharmacokinetics and pharmacodynamics of methadone enantiomers after a single oral dose of racemate.

BACKGROUND: The pharmacokinetics and dynamics of methadone are characterized by high interindividual variability. This study aimed to examine a number of factors that may contribute to this variability. METHODS: Eight healthy drug-free women were administered 0.2 mg/kg of R,S-methadone orally. The concentrations of methadone's enantiomers in plasma and urine were monitored for 96 hours. Vital signs, blood biochemical parameters, and pupillary diameter were monitored frequently during this period. Cytochrome P450 3A (CYP3A) activity and alpha1-acid glycoprotein (alpha1-AGP) concentrations and phenotypes were determined. Pharmacokinetic and pharmacodynamic modeling was used to assess the influence of the above-mentioned covariables on methadone enantiomer disposition and actions. RESULTS: The pharmacokinetic profile of the active enantiomer of methadone, R -methadone, showed a relatively normal distribution with 38% to 90% of the interindividual variability in modeled pharmacokinetic parameters being explained by their individual variability in CYP3A activity, the cumulative amount of the main CYP3A4 metabolite, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrolidine, excreted in the urine, the fraction unbound in plasma, and the alpha1-AGP orosomucoid 2 (ORM2) variant plasma concentration. S-Methadone showed an idiosyncratic distribution with largely unpredictable pharmacokinetics. Pupillary constriction response was highly variable between individuals. CONCLUSIONS: The disposition of the active enantiomer, R -methadone, can be predicted in part by CYP3A activity and protein binding to alpha1-AGP (ORM2), whereas S-methadone disposition is not well explained by the factors examined in this study. Central nervous system effects were difficult to interpret on the basis of plasma R-methadone pharmacokinetics.

Administration, Oral↗
PubMedDate not supplied

An individual-based model of Plasmodium falciparum malaria transmission on the coast of Kenya.

Individual-based models provide powerful tools to model complex interactions characterized by individual variability. This paper presents an object-oriented design for individual-based modelling of Plasmodium falciparum malaria transmission. Two kinds of objects, human and mosquito, that exhibit variability among individuals for parameters such as recovery and survival rates are defined. The model tracks the dynamics of human hosts and adult female mosquitoes individually. Immunity, modelled as a function of exposure history, is represented by reduced susceptibility and increased recovery rate. The model was calibrated using epidemiological data collected at 30 sites along the coast of Kenya. The sites were grouped into low, intermediate and high transmission based on mean daily human-biting rates. Simulation results show that malaria transmission was stable even in low transmission areas where the human-biting rate is approximately 0.5 bite per day. The model was used to examine the effect of infection control programmes that aim at interrupting transmission by reducing human-vector contact rates and implementing active case detection and drug treatment of infections. With this intervention, local elimination of malaria is likely with a probability of extinction of approximately 0.8 in low transmission areas. However, a small amount of immigration (> 0.3%) by infected people into the community could prevent local extinction of the parasite. In intermediate and high transmission areas, reduction in prevalence is short-lived and the probability of local elimination is low, even at high coverage levels of the intervention.

Age Distribution↗
PubMed1998

Drinking patterns within households: the estimation and interpretation of individual and group variables.

Levels of alcohol consumption tend to be similar for individuals living in the same household. This may be because: (a) individuals with similar characteristics collect in households (correlated effects); (b) individuals in the same household are influenced by common factors (exogenous effects); and/or (c) the consumption levels of an individual directly influences the consumption levels of other individuals in the same household (endogenous effects). Whichever of these three possibilities is the principal reason underlying household clustering of consumption levels has important policy implications. In this paper we propose a testing strategy to distinguish between the three types of effect in a cross-sectional data-set. Allowing for exogenous or endogenous effects shows that the significant socio-economic gradient in a model containing only individual variables arises because of misspecification. However, because we find significant evidence of correlated effects, we cannot identify whether it is endogenous or exogenous effects which give rise to statistically significant group level variables. The results indicate the possible pitfalls of omitting group level influences.

Adult↗
PubMed1989

Genetics of variability of CHD risk.

Many genetic and environmental factors act in combination to determine inter-individual variability in risk factor traits for coronary artery disease (CAD). Geneticists have focused on the study of continuously distributed biological traits such as total plasma cholesterol. In every population, plasma cholesterol has been implicated as a risk factor for CAD. Every biometrical study of the distribution of cholesterol in families has established a significant role of genetic variability in determining inter-individual differences in the population at large. While a few genes have been identified that have rare alleles with large effects on this trait, variability among individuals in most families is influenced by allelic variation in many genes as well as various environmental exposures. Therefore, in most families, one does not expect CAD to cosegregate with allelic variation at a single gene, and one does not expect each family to be segregating for the same subset of genes that influence variability in risk among individuals in the population at large. Strategies have been developed to address questions about the role of genes with common alleles in studies of intra- and interpopulation differences in risk for CAD. These strategies are illustrated here by a review of studies of the association between common allelic variations in the structure of the apolipoprotein (apo) E molecule and levels of total plasma cholesterol. This polymorphic gene may explain as much as 6% of the variation in risk for CAD in a North American population. In international comparisons, populations with a higher relative frequency of the E4 allele at this gene locus have higher cholesterol levels and higher rates of CAD deaths. Other candidate genes, in addition to apo E, need to be studied before individuals, families and populations at high risk for CAD can be identified more accurately.

Alleles↗
PubMed1983

How environments and persons combine to influence problem drinking. Current research issues.

In this chapter, a brief review of existing empirical research on environmental correlates of problem drinking is presented. The review shows that environmental factors do relate to the prevalence of drinking problems and also to the way drinking problems are expressed. In the major section of the chapter, however, it is shown that our present knowledge of how environmental and personal factors combine to influence problem drinking is quite limited, perhaps because almost all of the existing empirical research has attempted to account for problem drinking by means of individual variables alone, environmental variables alone, or in terms of linear combinations of individual and environmental variables. It is shown that alternative approaches offer more promise for understanding how individual and environmental factors combine to influence problem drinking; these approaches are aimed at accounting for problem drinking in terms of the mutual interdependence between persons and their environments. Within two hypothetical sets of data, a number of conceptual and methodological issues, problems, and features of these kinds of interactional or transactional approaches are then illustrated. It is shown that although such approaches offer a promise of greater understanding, they also present a set of interrelated problems which run the gamut from measurement, statistical analysis, experimental design, and sampling issues to paradigm issues lying close to the realm of the philosophy of science.

Adolescent↗
PubMed1986

Accuracy of Bayesian and Sawchuk-Zaske dosing methods for gentamicin.

The derived pharmacokinetic variable estimates from a Bayesian aminoglycoside dosing program were compared with those from the Sawchuk-Zaske method to determine which variable estimates were the most accurate in fitting the test dose and in predicting subsequent peak and trough serum concentrations. Data on 17 patients with moderately impaired but stable renal function were analyzed. All patients received gentamicin sulfate for treatment of their infections. To determine the individualized variables using the Bayesian program, demographic data, dosing history, and one (midpoint), two (peak and trough), or four serum drug concentrations were entered into the program. The Sawchuk-Zaske method used three serum concentrations determined following a first dose or four concentrations before and after a subsequent dose to derive individualized pharmacokinetic variables. The estimates of pharmacokinetic variables determined using the Bayesian method with one, two, or four serum concentrations did not differ significantly from those obtained using all the available serum concentrations with the Sawchuk-Zaske method. Although the actual numeric differences of prediction, absolute, and squared errors for fitting the test dose were minimal, significant differences were seen. All methods were similar in predicting serum concentrations from continued dosing. For the prediction error from continued dosing, a slight but significant difference was observed with the Bayesian method using one serum concentration when compared with the other methods. The Bayesian method using one, two, or four serum gentamicin concentrations individualized pharmacokinetic variables as well as the Sawchuk-Zaske method.

Aged↗
PubMed1991

Ethanol and physostigmine effects on open field behavior in Wistar rats.

The paper is aimed at the evaluation the effect of relatively low doses of ethanol and physostigmine salicylate on behavior of the male Wistar rat in an open field test. Both drugs were administered as a solution intragastrically 1 hour before the test started in dose ranges of 0.6-1.8 g/kg and 0.06-0.18 mg/kg, respectively. Lower doses of ethanol showed dose dependent biphasic effect on the ambulation and grooming time in animals. The medium dose 1.2 g/kg was rather ineffective in affecting rat behavior in the hole board test. Individual variables showed different sensitivity to individual ethanol doses. But from the medium dose, individual manifestations of ataxia were observed. Using the dose, only total ambulation, rearing time and rear latency were not affected when the rats were experienced with repeated exposure to open field arena or ethanol dose beforehand. Physostigmine alone increased defecation level significantly by two doses but lower doses changed some of the other variables, too. Combined administration of both drugs in medium doses did not affect the rat behavior considerably. The intra-trial habituation of three parameters of OF behavior seems to be influenced differently. Ethanol showed a tendency to facilitate the habituation of rearing, but rather to interfere with that of grooming. The later effect was also shown for physostigmine 0.12 mg/kg. The experimental part of the paper is supplied by the discussion of aspects important for modulation of rodent behavior in an open field test.

Alcoholism↗
PubMed2005

Genetic variability and clinical efficacy of morphine.

The individual variability of opioid pharmacology suggests that the patients' genetic disposition influences the response to opioids. Given the complexity of morphine pharmacology, variability may be caused by several genes. We review data which shows that variability in genes coding the enzyme metabolizing morphine (UGT2B7 gene), mu-opioid receptors (OPRM gene) and blood-brain barrier (BBB) transport of morphine by multidrug resistance transporters (MDR1 gene) influences the clinical efficacy of morphine. Furthermore, variability in an enzyme degrading catecholamines (COMT gene) alters the efficacy of morphine demonstrating that genetic variability in non-opioid systems may indirectly influence the clinical efficacy from morphine. Thus, results obtained so far strongly argue that opioid efficacy is partly related to inborn properties caused by genetic variability.

Catechol O-Methyltransferase↗