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At least 19 recordsLinked to original sources
PubMed1978

Experimental design deck for clinical research: A new learning resource in aid of scientific thinking.

The Experimental Design Deck for Clinical Research is a simulation of a problem in experimental design in a card deck format. It is intended to stimulate the development of skills in scientific thinking by allowing the student, in a self-directed fashion, to design a clinical trial to test either a given hypothesis (specific deck) or a hypothesis that the player provides (general deck). In addition to its use as an educational tool, the Experimental Design Deck can be used as a guide to the application of scientific thinking in a variety of biomedical activities. It can easily be modified for application to problems in nonmedical research and evaluation.

Clinical Trials as Topic↗
PubMedDate not supplied

An unbalanced experimental design for dose response studies.

Sixty sets of real data for 15 different pesticides from both sexes of Balb/C mice in two different experimental designs were generated at NCTR. The quantal responses for the dose groups in this data ranged from 1% to 90%. It was shown that the data could be represented equally well by a probit or logit transformation. It was further shown that the investment in terms of 7 times as many animals would greatly increase the confidence in estimating the parameters of the model and in predicting the dose at the low end of the dose response. Most important, it was shown that the estimation of a safe dose for a specified risk was greatly influenced by the choice of experimental design and method of extrapolation. It might be worth the investment in better experimental design to both the consumer and to the chemical industry if higher safe doses could be established which would allow the chemical to better accomplish its purpose and yet improve the assurance of the safety of the consumer.

Animals↗
PubMed1979

Comparison and evaluation of some experimental designs for use in carcinogen screening.

The development and evaluation of experimental designs for routine in vivo screening of chemicals for potential carcinogenic activity were considered. Such designs have played an important role in the Carcinogenesis Bloassay Program of the National Cancer Institute (NCI). In particular, the current one-stage 50-animal/group screen used by the NCI was considered. A specific two-stage alternative was proposed in which 35 animals/group were used; this alternative allowed for retesting of equivocal compounds. The proposed designs were evaluated in terms of sensitivity, specificity, and throughout. Despite the large number of tests made for each compound, the false-positive rate was found to be less than 0.07 for the current screen and less than 0.05 for the proposed two-stage alternative. The power of the one-stage and two-stage screens was comparable. The two-stage screen was shown to make about 30% more decisions per test period with a savings of around 28% in the expected number of animals needed per compound tested.

Animals↗
PubMed1979

Rationale and experimental design for the VA Cooperative Study of Anticoagulation (Warfarin) in the Treatment of Cancer.

Anticoagulants have been demonstrated to reduce tumor growth in certain experimental animal systems. Inhibition of clot formation interferes with tumor growth and spread while enhancement of coagulation promotes tumor growth and spread. The fact that the coagulation mechanism is commonly activated in human malignancy together with preliminary reports of therapeutic efficacy of anticoagulants suggests that the coagulation mechanism may be of pathophysiologic significance also in the growth of human tumors. A VA Cooperative Study has been established to test the hypothesis that warfarin anticoagulation will modify the course of malignancy in man. The purpose of this paper is to present the rationale and experimental design for this study with emphasis on management of anticoagulant administration in cancer patients. This paper serves as the basis for forthcoming reports of toxicity and therapeutic efficacy of warfarin in human malignancy.

Animals↗
PubMed1979

Evaluation of the chronic inhalation toxicity of a manganese oxide aerosol--I. Introduction, experimental design, and aerosol generation methods.

A brief literature review on manganese toxicity is presented; as related to designing a chronic inhalation study for evaluating methylcyclopentadienyl manganese tricarbonyl when utilized as a motor fuel additive. The experimental design of this study is described. The generation system utilized to simulate the manganese aerosol produced by an internal combustion engine is described in detail. This generation system operated twenty-four hours per day, seven days per week producing aerosols at 11.6, 112.5, and 1152 micrograms Mn/m3 with an aerodynamic diameter of approximately 0.11 micron.

Aerosols↗
PubMed1977

Experimental design and statistical analysis of an in-use test of germicidal detergents.

Present methodology for the in-use testing of germicidal detergents is too time-consuming for routine use by a hospital environmentalist. A simplified experimental design and statistical analysis, amenable to routine use, is presented for the in-use testing of germicidal detergents against water alone. As an illustration of our methodology we evaluated two germicidal detergents versus water alone. Under our conditions of use, it was found that water alone was equally and significantly as effective (p less than 0.001) as the two germicidal detergents in reducing microbial contamination of floors.

Anti-Infective Agents, Local↗
PubMed1977

Apomorphine-induced locomotion and gnawing: evidence that the experimental design greatly influences gnawing while locomotion remains unchanged.

In a recent study we have shown that it was possible to recognize and record two independent behavioural patterns elicited by apomorphine (s.c.): one behaviour characterized by increased locomotion, sniffing and repetitive head and limb movements and another, characterized by compulsive gnawing. In the present study we have further characterized the gnawing and the locomotion patterns, their dependence on the experimental design and on the test environment. We found that the apomorphine-induced gnawing was easily modified by factors such as the design of the test-box and the habituation of the animal to the test-box. Locomotion, on the other hand was essentially independent of such factors and seemed more compulsive than the so-called "compulsive gnawing".

Animals↗
PubMed1979

Factorial experimental design applied to the immunological study of two foot-and-mouth disease virus subtypes. 2. Theoretical study of experimental models.

A certain number of theoretical models of immunological relations that 2 foot-and-mouth disease viruses can support, were constructed so as to discuss in each case, the results of the factorial analysis of the data. This method provided a specific answer to each of the questions that were asked in the presence of a test of this kind. The results obtained with several immunological cross-tests comparable to that of the A Greece 69-A Allier viruses, illustrated most of the theoretical models.

Animals↗
PubMed1979

Experimental design for the surgical relocation of the ovary into the vaginal fornix.

After translocation into the vaginal vault while attached to a pedicle consisting of the infundibulo-pelvic ligament, the ovary was found to maintain its function in laboratory primates. In the majority of the baboons the ovulatory pattern returned within a few weeks after the surgical procedure. The only significant complication was a transitory, and self-limited, infection which was evident on inspection and on the biopsy specimens, but caused no clinical symptoms. By comparing the surgical outcome in two primate species, namely Papio Cynocephalus and Macaca Arctoides, it could be deduced that the Homo Sapiens would be a more suitable experimental model than either of the laboratory primates used in this research. Because there are potentially effective methods for reducing the likelihood of postoperative infection in the relocated ovary, the experience gained by this new method suggests the possibility that it could be utilized in the future for the purpose of collecting ova for in vitro fertilization in carefully selected, and otherwise untreatable, cases of female sterility.

Animals↗
PubMed1979

Drug concentrations in neuropsychiatry. Methodological pitfalls: the influence of experimental design on results.

The valid study of relationships between pharmacokinetic measurements and clinical effects of psychotropic drugs depends on: (i) analytical methods for the drugs; (ii) the fluid assessed and pharmacokinetic derivations; (iii) clinical assessments and the nature of psychiatric illness; and (iv) statistical work. Standard problems with analytical methods include lack of specificity, unjustified claims for sensitivity, and failure to recognize metabolites as potential analytical contaminants and compounds for separate study. Problems with pharmacokinetic derivations include inappropriate calculations and incorrect assignment of terms such as 'half-life'. Clinical difficulties mostly relate to variations between patient groups, selection procedures and rating methods, and to timing of samples. Statistical controversies concern the calculation of metabolite ratios, pooling of data from drugs and their metabolites, and abuse of statistical techniques. These methodological problems are illustrated by reference to work with phenothiazines, tricyclic antidepressants, lithium, benzodiazepines and anticonvulsants.

Body Fluids↗
PubMed1978

Importance of interactions between nutrients and environmental contaminants as a factor in experimental design in toxicological research: with emphasis on selenium and ascorbic acid.

Interactions between dietary components and environmental contaminants may influence the outcome of toxicological testing. A comparison was made between the vitamin and mineral content of laboratory animal basal diets as supplied by two major feed companies. Striking differences in nutrient content of Guinea pig, rat, and primate diets, as supplied by these companies are cited. Attention is drawn to the lack of data on selenium content of these feeds. The importance of Vitamin C in regards to ameliorating toxic effects of heavy metals is discussed.

Animal Feed↗