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Biomedical subjects

W W Davis

Publications and source records attributed to W W Davis.

At least 19 recordsLinked to original sources
PubMed1992

DSM-IV and new diagnostic categories: holding the line on proliferation.

The authors discuss aspects of the decision-making process for including "new" diagnostic categories in DSM-IV. They detail the different kinds of new categories proposed for inclusion in DSM-IV and discuss the risks and benefits of incorporating them. The authors comment on whether new diagnostic categories should be included in official nosologies as a stimulus for research or as a culmination of research. They also highlight problems with "sunsetting" diagnoses. The criteria for change in DSM-IV--a way to deal with the expanding array of proposals for additional diagnostic entities--are discussed. The authors also offer a series of specific examples of the different kinds of new categories being considered for inclusion in DSM-IV.

Anxiety Disorders↗
PubMed1991

Toward an empirical classification for the DSM-IV.

The provision of explicit and specific diagnostic criteria in the Diagnostic and Statistical Manual of Mental Disorders (DSM; American Psychiatric Association, 1980, 1987) was instrumental in the production of a substantial amount of informative research. The major emphasis in the preparation of the DSM-IV has been to maximize the impact of this accumulating research on the revision and to document the rationale and empirical support for any changes that are made. In this article we discuss the empirical basis for the DSM-IV. The historical context provided by the previous editions is briefly presented and followed by a description of the process by which the DSM-IV is being constructed. The input of empirical data through literature reviews, data reanalyses, and field trials is described, and an illustration with the antisocial personality disorder diagnosis is given.

Antisocial Personality Disorder↗
PubMed1991

An A to Z guide to DSM-IV conundrums.

The work on the 4th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) poses many puzzling conundrums that touch on complicated and important theoretical and practical issues. None of these can be resolved in the DSM-IV, but we hope that the Task Force's decisions will be informed by thorough reviews of the currently available evidence and extensive input from all sectors of the mental health field. In this article we provide an alphabetical guide to DSM-IV conundrums that we hope will stimulate comments, suggestions, and criticisms about the work of the Task Force.

Diagnosis, Differential↗
PubMed1990

DSM-IV: work in progress.

The authors present an overview of the work in progress on DSM-IV. After a brief historical review, they discuss the principles and multiple purposes of the DSM-IV effort and outline the three stages of its empirical documentation: systematic literature reviews, analysis of unpublished data, and field trials. Next, they discuss several of the basic conceptual issues that are implicit in revising a nomenclature. These include the definition of mental disorder, the balance between multiple diagnosis and differential diagnosis, the use of categorical and dimensional models of classification, and issues involved in the construction of criteria. Finally, they summarize the most important specific questions being reviewed by each of the DSM-IV work groups.

Humans↗
PubMed1971

Disc plate method of microbiological antibiotic assay. I. Factors influencing variability and error.

Several factors are investigated that normally cause variation in zone diameters in conventional disc plate diffusion assay procedures. Of these factors the most serious is the unequal exposure of the individual plates at top or bottom of stacks to temperatures above and below room temperature. This unequal temperature exposure is avoided by novel handling and incubation procedures. A major variable, but one which can be controlled, is the varying time interval between pouring seeded agar and the time of applying the pads with antibiotic to the plates. This influence of time of setting and the effects of several other sequential operations are combined into a composite variable. This variable is then accounted for and normalized by interposing "external" reference plates set with a reference solution in the sequence of approximately 100 plates. No "internal" reference zones are employed. Such factors as volume of agar poured, wedge shape of agar in a dish, volumetric errors in dilutions, and timing considerations are studied and discussed. The results of this study form the basis for a test protocol which is presented in a following paper.

Agar↗
PubMed1971

Disc plate method of microbiological antibiotic assay. II. Novel procedure offering improved accuracy.

A detailed disc plate procedure is introduced for assay of antibiotics. The procedure is based on a previous study by the authors and deviates from conventional procedures in several respects: selected plastic petri dishes are employed; critical temperature control is simply provided at all stages of the test with refrigeration of the plates never used; all dilution is done with displacement microburettes; six pads (6.3 mm diameter) per dish are employed, all filled with the same unknown or reference solution; the sequence of all plates handled on 1 day is made a part of the protocol which allows accounting for the influence of the order of pouring and setting the plates; external reference plates are set at specified locations in the sequence; and, by averaging the diameters of all zones on a plate, most of the consequence of wedge shape of agar in plates, which is common and almost unavoidable, is removed. The present method is economical, uses simple facilities, and provides good accuracy of test results. Bacillus subtilis was most commonly employed, but other organisms may be employed in the present procedure.

Agar↗
PubMed1969

Inhibition of the effects of angiotensin II on adrenal steroid production by dietary sodium.

The pressor octapeptide, angiotensin II, can stimulate the production of aldosterone by the adrenal cortex. The present results show that in the dog a high-sodium diet can eliminate the steroidogenic action of angiotensin II, which is thus dissociated from the pressor action which remains. Angiotensin II was infused intravenously for 48 hours into conscious, undisturbed hypophysectomized dogs that were receiving each day either 60 or 200 mEq of dietary sodium. Blood pressure and secretion of aldosterone, corticosterone, and cortisol were measured (1) throughout the infusion in some dogs, and (2) at the end of the infusion in all dogs. In those dogs receiving 60 mEq of sodium, angiotensin II elevated the blood pressure and produced sustained increases of secretion of aldosterone, corticosterone, and cortisol. In those dogs receiving 200 mEq of sodium, angiotensin II, while retaining its pressor activity, had no effect on the production of aldosterone, corticosterone, or cortisol after 24 hours. Thus, if angiotensin II can produce hypertension clinically, there need not be secondary aldosteronism as well.

Adrenal Cortex Hormones↗
PubMed1968

Sites of action of sodium depletion on aldosterone biosynthesis in the dog.

Secretion of cortisol, corticosterone, and aldosterone was measured in vivo in normal and sodium-depleted hypophysectomized dogs. Biogenesis of steroids was then measured in vitro with outer slices of the adrenals of the same dogs. In some studies, metyrapone or puromycin was added. In vivo, sodium depletion stimulated the production of cortisol, corticosterone, and aldosterone. In vitro, tissues from sodium-depleted animals released more aldosterone, but less corticosterone than those from sodium-replete controls. The results are interpreted to indicate that (a) biosynthesis of aldosterone is regulated at at least two sites in the biosynthetic pathway. The final conversion, that of corticosterone to aldosterone, is stimulated by sodium depletion. This effect persists for at least 3 hr while slices from sodium-depleted dogs are incubated in vitro. Stimulation at this site is thus relatively stable in vitro; its activation by sodium depletion is not inhibited by puromycin in the dog. Stimulation at this site can explain, at least in part, the increased effectiveness of adrenocorticotropin (ACTH) on aldosterone biogenesis during sodium depletion.(b) the earlier site at which sodium depletion stimulates the secretion of aldosterone is "above" the position of desoxycorticosterone in the pathway; it is probably at the conversion of cholesterol to pregnenolone. Stimulation at this site is quickly lost during incubation of adrenal slices. It is thus relatively unstable in vitro; its activation by sodium depletion is inhibited by puromycin in the dog.

Adrenal Glands↗