Methodological considerations in behavioral toxicology in infants and children.

The effect of exposure to neurotoxic substances on cognitive and behavioral development has become an important research focus within developmental psychology in recent years. Research design considerations are critically important in these studies, because random assignment and experimental control of extraneous influences are not possible and effects are often subtle and not seen in every exposed individual. Oversampling from the most highly exposed individuals is usually needed to ensure detection of toxic effects. Valid and reliable assessment must be made of important potential confounders, yet control variables must not be so confounded with exposure as to obscure toxic effects. In the assessment of developmental outcome, apical measures may provide the greatest sensitivity, and narrow-band tests, more information about the specific nature of the impairment. Dose-response analyses can help determine the lowest exposure levels at which deficits are seen ("thresholds"). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Methodological approach to regulation of polyamine

This brief article is dedicated to the late Professor Morizo Ishidate, and concerned in a methodology developed by the author and collaborators, aiming at the regulation of polyamine, especially, the regulation of spermidine synthase. The content is separated in 3 sections. The first section on the development of analytical methods, contains seven items, e.g. fluorometric determination of polyamines by fluorescamine, analysis of naturally occurring polyamines by GC and GC-MS, etc. The second section on the syntheses of needed compounds, contains three items, e.g. syntheses of decarboxylated S-adenosylmethionine which is a substrate for spermidine synthase and its related compounds, syntheses of 15N-enriched polyamines applicable to the preparation of various polyamines, etc. The last section on the studies of aminopropyl transferases, contains three items, e.g. purification of spermidine synthase from mammalian tissues using ATPA-Sepharose, a novel affinity carrier, newly developed inhibitors for the enzymes, etc.     

Phylogenetic analysis of nucleotide sequences: an algebraic approach

Retinoids constitute a very promising class of agents for the chemoprevention or treatment of breast cancer. These retinoids exert their biological activity through two distinct classes of retinoic acid (RA) receptors (R), the RAR isotypes (alpha, beta, and gamma) and the three RXR isotypes (alpha, beta, and gamma) and their numerous isoforms which bind as RXR/RAR heterodimers to the polymorphic cis-acting response elements of RA target genes. With respect to these numerous receptor sub-types, the retinoid-induced effects at the biological level include marked modifications with respect to both cell proliferation and cell death (apoptosis), and also in the induction of differentiation processes. The present study aims to characterize the effect which four retinoids (TTNPB, 9-cis-RA, LGD 1069, 4-HPR) with distinct RAR/RXR binding properties induced on various in vitro and in vivo mouse and human breast cancer models. The experiments with the retinoids were carried out in comparison with the anti-estrogen tamoxifen and the anti-progestagen RU-486 compounds. The results show that the 6 compounds under study were markedly more efficient in terms of growth inhibition in the human T-47D cell line when maintained under anchorage-independent culture conditions than when maintained under anchorage-dependent ones. While RU-486 exhibited a weak statistically significant (p < 0.05) influence on the growth of the T-47D stem cells, tamoxifen had a marked inhibitory influence on the growth of these cells. Of the four retinoids, 4-HPR was the least effective since the lowest doses tested (1 and 0.1 nM) exhibited no statistically (p > 0.05) significant influence on the growth of the stem cells. The most efficient retinoid was TTNPB. It was only at the highest dose (10 microM) that tamoxifen and RU-486 showed a weak inhibitory influence on the growth of the T-47D non-stem cells while all 4 retinoids exerted a significant inhibitory influence on the growth of these non-stem cells, with 4-HPR being the most efficient (P < 0.001) at the highest dose, but ineffective (P > 0.05) at the lowest. Tamoxifen and TTNPB were tested in vivo on hormone-sensitive (HS) and hormone-insensitive (HI) strains of the MXT murine mammary carcinoma. While TTNPB appeared to be equally efficient in terms of growth inhibition in both MXT-HS and MXT-HI models, tamoxifen had only a marginal inhibitory influence on the growth of the MXT-HI strain but did inhibit growth in the case of the MXT-HS one. TTNPB was markedly more efficient than tamoxifen in terms of both inhibiting the cell proliferation level (measured by means of computer-assisted microscopy applied to Feulgen-stained nuclei, a method which enables the percentage of cells in the S phase of the cell cycle to be determined) and triggering cell death (measured by means of the determination of the transglutaminase activity) in both the MXT-HI and MXT-HS models. The very significant TTNPB-induced inhibition of the macroscopic MXT-HS growth rate relates to the triggering of cell death (apoptosis) rather than to an inhibition of cell proliferation. All these results clearly indicate that retinoids are very efficient agents against breast cancer, at least as efficient as tamoxifen.     

Self-injurious behavior: A behavioral analysis.

Discusses the phenomenon of self-injurious behavior (SIB) in terms of its frequency of occurrence, the people whom it effects, its various topographies, some treatment methods, and a behavioral analysis of its etiology. Studies that have used the positive reinforcement of alternative behaviors, withdrawal of positive reinforcement, extinction, and punishment to control SIB are reviewed and evaluated. Some ethical and practical considerations regarding the use of punishment for SIB are discussed. A discriminative stimulus-conditioned reinforcer hypothesis and an avoidance hypothesis are proposed to explain SIB in terms of learning principles. Some of the possible aberrant organic foundations of SIB are also discussed. (43 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Methodological issues in a team approach to community health needs assessment

This study was designed to determine the effects of hypothyroidism during late fetal life in pigs on (1) the perinatal pattern of plasma levels of thyroxine (TT4), total 3,5,3'-triiodothyronine (TT3) and free T3 (FT3), and liver 5'-deiodinase activity, and (2) the early postnatal development of thermoregulation. Fetal hypothyroidism (test animals) was induced by feeding the sow a high glucosinolate rapeseed diet. Plasma levels of thyroid hormones, thyroid gland weights and liver 5'-deiodinase activity of control animals increased during late gestation (P < 0.01). The early postnatal period was characterized by a surge in thyroid hormone levels during the first 6 h (P < 0.05), followed by a transient decrease at 12 h and a second rise by 24 h after birth. This surge was much higher (P < 0.01) for TT3 than for TT4, but liver 5'-deiodinase activity did not change during the first 24 h of life. Fetal hypothyroidism was characterized by lower plasma levels of thyroid hormones (P < 0.05), and lower hepatic 5'-deiodinase activities (P < 0.01) than in control fetuses at 110 d of gestation. During the first 6 h of life, test pigs had lower levels of TT4 (P < 0.05) but exhibited a greater postnatal surge in TT3 and FT3 (P < 0.05) than did the controls. The minimal and summit metabolism of the control pigs increased markedly (P < 0.01) during the first 2 d of life, without any significant change in thermal body conductance, suggesting that this age-related improvement in thermoregulation was due to the development of the ability to produce heat.(ABSTRACT TRUNCATED AT 250 WORDS)     

Confocal fluorescence coincidence analysis: an approach to ultra high-throughput screening

Fluorescence-based assay technologies play an increasing role in high-throughput screening. They can be classified into different categories: fluorescence polarization, time-resolved fluorescence, fluorescence resonance energy transfer, and fluorescence correlation spectroscopy. In this work we present an alternative analytical technique for high-throughput screening, which we call confocal fluorescence coincidence analysis. Confocal fluorescence coincidence analysis extracts fluorescence fluctuations that occur coincidently in two different spectral ranges from a tiny observation volume of below 1 fl. This procedure makes it possible to monitor whether an association between molecular fragments that are labeled with different fluorophores is established or broken. Therefore, it provides access to the characterization of a variety of cleavage and ligation reactions in biochemistry. Confocal fluorescence coincidence analysis is a very sensitive and ultrafast technique with readout times of 100 ms and below. This feature is demonstrated by means of a homogeneous assay for restriction endonuclease EcoRI. The presented achievements break ground for throughput rates as high as 10(6) samples per day with using only small amounts of sample substance and therefore constitute a solid base for screening applications in drug discovery and evolutionary biotechnology.     

Musk xylene: analysis, occurrence, kinetics, and toxicology

1,3-Dimethyl-2,4,6-trinitro-5-tert.-butylbenzene (musk xylene, MX), a synthetic musk, is often used in fragrances and soaps to substitute the natural musk. MX belongs to the common group of nitromusk compounds. The main environmental intake of MX occurs after sewage introduction. The consumption of fish and drinking water as well as the use of body care and perfumed household products could lead to an ingestion of this substance in humans. Although the acute oral and dermal toxicity of MX is low, some hint for the carcinogenic potential of MX was found in one animal experiment. These findings and the high potential of MX as environmental contaminant, it is stable against biological and chemical degradation and it is highly lipophil, raised considerable attention in the field of environmental medicine. Biological monitoring and the toxicology of MX, which previously has been described to occur in human milk, human fat tissue, as well as human blood samples, are of central interest. The aim of this article is to summarize the data on the analysis, occurrence, kinetics, and toxicology of MX. As there is a lack of knowledge on human toxicity and human carcinogenicity of MX, a final evaluation of the toxicological data with regard to public health is still impossible. Nevertheless, in view of the published data about MX, there is no evidence for any substantial human risk at the moment.     

Clinical assessment of DNA analysis for toxicology

Decreased diurnal blood pressure variability and low dehydroepiandrosterone sulfate (DHEAS) levels are important predictors of cardiovascular morbidity and mortality. The aim of the study was to determine the relationship between DHEAS levels and diurnal blood pressure variability in normotensive subjects and in patients with essential hypertension of both genders. An ambulatory blood pressure monitor (ABPM), Meditech O2 device and radioimmunoassay were used for ambulatory blood pressure monitoring and the determination of DHEAS levels, respectively. A close correlation (P < .001) was found between the diurnal indices and plasma DHEAS levels of the 387 subjects (86 normotensive and 301 hypertensive patients) participating in the study. Decreased plasma DHEAS levels were associated in both genders, and in both normotensive and hypertensive patients with significantly (P < .001) lower diurnal indices. There was a close correlation (P < .001) between the age-related decrease in plasma DHEAS levels and diurnal indices in both genders. Systolic and diastolic blood pressure variability changed parallel to plasma DHEAS levels in both genders, whether hypertension was present or not. Additional investigations are needed to find out whether reduced DHEAS levels play a role in decreased diurnal indices or whether both can be traced back to one and the same cause.     

Methodological problems in AIDS behavioral research: Influences on measurement error and participation bias in studies of sexual behavior.

An unprecedented number of human sexuality studies have been initiated in response to the acquired immune deficiency syndrome (AIDS) epidemic. Unfortunately, methodological developments in the field of sex research have been slow in meeting the demands of AIDS investigations focusing on the diverse populations at risk for human immunodeficiency virus (HIV) infection (e.g., adolescents, gay men, iv drug users, ethnic minorities, elderly transfusees). In this article the authors review and integrate current literature on measurement error and participation bias in sex research, with an emphasis on collecting sexual information in the context of AIDS. The relevance of these findings for AIDS-related sex research is discussed, and recommendations are made to guide future investigations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A behavioral approach to Tourette's syndrome.

Notes that Tourette's syndrome, which includes the compulsive vocalization of obscene words, has been attributed to both organic and psychological factors. Although no conclusions about the etiology of the behavior could be drawn, the operant nature of the symptoms was demonstrated in a case study of a 12-yr-old boy with normal intelligence in the manipulation of responses by varying contingencies of reinforcement. Implications for management and therapy with such children are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A behavioral approach to college teaching.

Describes a program of research on teaching methods and their results, comparing these techniques with other instructional procedures. The research was conducted from the philosophical and methodological perspective of an empirical approach to instructional procedures in higher education. The techniques included using skilled students to teach other students, precise specification of curricula, continuous recording and graphing of performance data, individualized definition of performance criteria, and frequent assessment integrated with teaching. The roles of a number of variables critical to the success of such teaching activities are discussed. (25 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On image analysis in fractography (Methodological Notes)

As other spheres of image analysis, fractography has no universal method for information convolution. An effective characteristic of an image is found by analyzing the essence and origin of every class of objects. As follows from the geometric definition of a fractal curve, its projection onto any straight line covers a certain segment many times; therefore, neither a time series (one-valued function of time) nor an image (one-valued function of plane) can be a fractal. For applications, multidimensional multiscale characteristics of an image are necessary. “Full” wavelet series break the law of conservation of information.     

Resource-use analysis of a medical toxicology consultation service

In contrast to the wealth of knowledge about the organizational rules of adult central pattern generators, far less is known about how these networks are assembled during development. The basic architecture for adult central pattern generators appears early in development but different generators may follow completely different developmental pathways to reach maturity. Recent evidence suggests that neuromodulatory inputs, in addition to their short-term adaptive control of central pattern generator activity, play a crucial role in both the final developmental tuning and the long-term maintenance of adult network function.     

Wildness and domestication in Mus musculus: A behavioral analysis.

Examined the behavioral characteristics which differentiate wild and domesticated mice together with some of the possible mechanisms which produce them. 1 wild stock, 3 inbred strains (C57 B1/10j, DBA/2j, and A/j), and 3 inbred crosses (N = 277) were divided by litter at weaning and assigned in equal numbers to a laboratory or naturalistic environment. After 90 days Ss were run through a test battery. Wild Ss were characterized by poor avoidance, high activity, long emergence latencies, and extensive freezing behavior. Hybrids were not consistently more like wilds than inbreds and showed little effect of differential rearing. Wilds and inbreds differed in their response to differential rearing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ontogeny of amphetamine anorexia in rats: A behavioral analysis.

Conducted 4 experiments with 246 Sprague-Dawley rats to ascertain the effects of dextroamphetamine (DAM; 1 or 2 mg/kg) on the behaviors associated with feeding in weanling and preweanling rats. The 1st 2 experiments produced the following results: (a) In 5-day-old Ss, DAM increased speed of approach to an anesthetized mother; (b) at 15 days of age, DAM increased speed of approach to the mother and produced marked weight loss (relative to the weight of controls), slowed or reduced frequency of attachment to the nipple, and decreased time spent nursing; and (c) at 25 days of age, DAM disrupted all aspects of the feeding process except initial approach. Weight gain, time spent in contact with the mother, time spent nursing, and time attached to the nipple were all reduced by the drug. In Exps III and IV, milk was delivered to Ss at 5, 15, and 25 days of age through tongue cannulas, which allowed ingestion without suckling. Under these circumstances, DAM produced clear-cut anorexia in Ss of all 3 ages. It is concluded that in early development, the anorectic effects of DAM are overridden by the strong suckling response that is not disrupted by the drug. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hypnotic blindness: A behavioral and experiential analysis.

This research examined the influence of visual information on a decision task that subjects were administered during hypnotically suggested blindness. Real, hypnotizable subjects and simulating, unhypnotizable subjects were tested in two experiments. Experiment 1 focused on behavioral responses, and Experiment 2 focused on experiential reactions. In both experiments, the findings indicated that the behavioral responses of reals were influenced by visual information despite their reported blindness. The behavioral responses of reals and simulators were essentially similar. The experiential data in Experiment 2 provided information about the phenomenal nature of subjects' reported blindness. The experiential reactions of reals and simulators were essentially different. The research is discussed in terms of the issues that need to be considered in the development of a model of hypnotic blindness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Behavioral interventions in resource conservation: A systems approach based on behavioral economics.

Outlines some of the advantages of an integration of psychological (social-learning) and economic conceptualizations when developing behavioral interventions in resource conservation. The procedures and results of rebate studies in residential energy and water conservation are presented in which rebates were used as a method to modify conservation behaviors and to estimate experimental price elasticity in contrast to the usual econometric methods. A meta-analysis is performed on behavioral energy studies conducted from 1973 to 1980, which shows that the effectiveness of rebates and feedback is partially explained by an economic factor. Also reviewed are field-based studies designed to modify perceptions of comfort and residential energy conservation in addition to the development of a rebate system instituted to reduce domestic water consumption. Maximization theory is offered as an integrative, conceptual framework that may be useful for planning resource conservation interventions. (49 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hierarchical modeling of sequential behavioral data: An empirical Bayesian approach.

The authors review the common methods for measuring strength of contingency between 2 behaviors in a behavioral sequence, the binomial z score and the adjusted cell residual, and point out a number of limitations of these approaches. They present a new approach using log odds ratios and empirical Bayes estimation in the context of hierarchical modeling, an approach not constrained by these limitations. A series of hierarchical models is presented to test the stationarity of behavioral sequences, the homogeneity of sequences across a sample of episodes, and whether covariates can account for variation in sequences across the sample. These models are applied to observational data taken from a study of the behavioral interactions of 254 couples to illustrate their use. (PsycINFO Database Record (c) 2010 APA, all rights reserved)