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Biomedical subjects

W M Davis

Publications and source records attributed to W M Davis.

At least 19 recordsLinked to original sources
PubMed1992

Freezing action of a metabolite of haloperidol in frogs.

In vivo metabolism studies led to the identification of a previously proposed metabolite of haloperidol, 4-(4'-chlorophenyl)-4-piperidinol (CPPO), in the liver of a haloperidol-treated rat. However, the secondary metabolites of CPPO that we have proposed were not observed in this study. Neurotoxicity studies in frogs, which have been used to detect N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) action, showed that CPPO did not mimic the neurotoxicity of MPTP but caused a delayed and persistent freezing action in Rana pipiens frogs. It is proposed that this action may contribute to some of the delayed side-effects associated with haloperidol therapy.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1992

Psychopharmacology of lycanthropy.

OBJECTIVE: To develop pharmacotherapies for the orphan disease lycanthropy through the pursuit of the etiologic hypothesis of a genetically determined hypersecretion of endogenous lycanthropogens. DESIGN: Quadruple-blind, Rubik's Cube matrix analysis. SETTING: Community practice and malpractice. PARTICIPANTS: Subjects selected from inbred Ruficolla populations in Mississippi, Georgia, North Carolina and Minnesota. All who entered the study finished it. INTERVENTIONS: Chemical screening of blood samples over a hypothesized secretory cycle of lycanthropogen peaking on the day of maximum lunar illumination. Administration of synthetic lycanthropogens for behavioural testing. Experimental lycosomatization through the illumination method of Kirschbaum. OUTCOME MEASURES: None were post hoc, but some are still in hock. MAIN RESULTS: Two putative lycanthropogens were isolated from the blood samples. Structural elucidation and synthesis permitted animal and clinical trials; in each of these, behavioural dysfunction was observed. Antilycanthropogen strategies included application of the principle of caged compounds and generation of a therapeutic immunoglobulin. The effects of a newly developed antihirsutic agent seemed promising. An interaction of the lycanthropogen-secretion system and ethanol was noted, which may explain behavioural aspects of alcoholism. CONCLUSIONS: The incidence of lycomania in North America is underestimated. Soon-to-be-available pharmacotherapies should promote its early detection and treatment. Full control may depend upon advances in gene therapy.

Delusions↗
PubMed1992

Replacement of freeze-dried allogeneic cartilage chin graft with host bone. A case report.

Facial contour and augmentation procedures are frequently performed by oral and maxillofacial surgeons either as a primary surgery or in conjunction with corrective jaw surgery. The success of these procedures depends on the stability of the material used. This case demonstrates the stability and eventual osseous replacement of allogeneic freeze-dried cartilage as an augmentation material.

Adult↗
PubMed1992

Acute cardiovascular effects of methyl methacrylate monomer: characterization and modification by cholinergic blockade, adrenergic stimulation and calcium chloride infusion.

1. Methyl methacrylate monomer (MMA) given by i.v. infusion to anesthetized dogs caused a sustained hypotension, bradycardia, reduction of cardiac output and stroke volume, and increased peripheral resistance. 2. Epinephrine i.v. could reverse the hypotension but not the bradycardia; isoproterenol i.v. could reverse the bradycardia but not the hypotension. 3. Bilateral cervical vagotomy prevented bradycardia but not other cardiovascular effects of MMA, and prevented all respiratory effects except hypoxemia. 4. Calcium chloride i.v. reversed all circulatory changes except bradycardia; a combination of atropine and calcium reversed all cardiovascular changes from MMA.

Animals↗
PubMed1992

Effect of methyl methacrylate on isolated atria and interaction with isoproterenol, atropine and calcium chloride.

1. Spontaneous rate and contractile force of isolated rat and rabbit atria suspended in a tissue bath were recorded before and after drugs. Methyl methacrylate monomer (MMA) alone both decreased force and increased rate dose-dependently. 2. Concentrations of calcium chloride or isoproterenol that alone increased both rate and force of rat atrial contraction were fully and only partially able, respectively, to restore force to normal after MMA. 3. Atropine prevented changes in rat atrial function from low-effective doses of MMA, but not higher ones; it also failed to prevent the reduction of contractile force by a calcium channel blocker, verapamil. 4. There are similarities but also differences between actions of MMA and verapamil on rat atria.

Animals↗
PubMed1992

Solitary rectal ulcer syndrome: not always ulcerated.

Our patient had a nonulcerated rectal lesion grossly resembling a villous tumor, but microscopically proving to be a solitary rectal ulcer. We have discussed the clinical and pathologic findings and the probable relationship of the lesion to straining at the stool.

Biopsy↗
PubMed1991

Effect of sex steroids on cocaine lethality in male and female mice.

1. Endogenous sex steroid levels were altered in mice via gonadectomy, via physiological or supraphysiological doses of testosterone and/or estradiol, and via tamoxifen dosing to antagonize estrogens. 2. The role of sex hormones in susceptibility to cocaine lethality was examined via the response of mice after endocrine alterations to an intraperitoneal (i.p.) cocaine HCl (75 mg/kg). Incidence of deaths was significantly decreased only in sham-operated males receiving estradiol or tamoxifen and in ovariectomized or sham-operated females receiving doses of estradiol. 3. The levels of estradiol in both sexes appeared to be more influential than were levels of testosterone as a determinant of susceptibility to cocaine.

Animals↗
PubMed1991

Factors in the lethality of i.v. phencyclidine in conscious dogs.

1. Pretreatment were pancuronium prevented convulsions and hyperthermia, but had no effect on acidemia or changes in cardiovascular parameters after intravenous (i.v.) infusion of phencyclidine (PCP). 2. While dogs survived higher amounts of PCP, they failed to regain spontaneous respiratory function. 3. Mechanical ventilation alone increased the mean lethal dose/time of PCP and reduced the effects of PCP on arterial systolic pressure, cardiac output, and PCO2. 4. EKG showed ventricular arrhythmias, which progressed to death. 5. Phenytoin pretreatment plus respiratory assistance increased the lethal dose and reduced PCP effects on cardiovascular parameters, body temperature, and cardiac rhythm. 6. Blocking of convulsions prevented hyperthermia and acidemia; respiratory support reduced circulatory effects, but respired dogs then died, at higher doses, from a primary myocardial toxicity of PCP.

Animals↗
PubMed1991

Respiratory and circulatory effects of centrally administered phencyclidine in anesthetized dogs.

1. Anesthetized dogs were given phencyclidine HCl (PCP) by intracerebroventricular (i.c.v.) injection. 2. Physiological parameters were monitored after consecutive doses of 0.5, 1.0 and 2.0 mg of PCP. 3. Dose-related changes seen, including bradycardia, hypotension and bradypnea, were opposite to those produced by i.v. doses. 4. Single doses of 1.0 or 2.0 mg of PCP confirmed the prior observations, and the latter provided the baseline for further observations on dogs receiving PCP before various i.c.v. pretreatments--atropine, haloperidol, phentolamine or propranolol--in efforts to characterize the central neurotransmitter system(s) involved in the PCP effects.

Anesthesia↗
PubMed1990

Pharmacologic and toxicologic effects of di(beta-phenylisopropyl)amine (DPIA) in rats and mice.

1. Di(beta-phenylisopropyl)amine (DPIA) given i.p. to mice and rats in sublethal doses caused increased motility, mild stereotypic behavior and suppression of food intake. Repeated daily doses led to enhanced motor stimulation, and in one group, 40% lethality, indicating development of "reverse tolerance". Brain monoamine modifiers prevented DPIA-induced motor activity. 2. Treatment with toxic i.p. doses of DPIA enabled determination of the LD50, which was 106.8 mg/kg for isolated mice and 89.7 mg/kg for mice kept in aggregation after dosing. Possible antidotal agents given before a high DPIA dose (LD50) protected significantly against lethality. 3. Combinations of DPIA with (+)-amphetamine in mice at lethal doses showed a subadditive synergism. 4. Effects of DPIA on the cardiovascular system, both i.v. in anesthetized rats and in isolated atrial preparations, were mainly opposite to those of (+)-amphetamine, namely decreases in blood pressure, force of contraction and heart rate.

Amphetamine↗
PubMed1987

A method to facilitate placement of screws for sagittal ramus osteotomy.

This article describes a method of placing screws for bilateral sagittal ramus osteotomies. The technique, a slight modification of previous methods, eliminates the need for use of a clamp, aids in proximal segment control, and employs a single transosseous wire and two transcortical screws. This method has been used in more than 50 cases and has been proved to be adaptable and stable, even without intermaxillary fixation.

Bone Screws↗
PubMed1987

Comparison of stimulants and hallucinogens on shuttle avoidance in rats.

Rats were trained to a high level of performance of a conditioned avoidance response in a shuttlebox to test effects of several classical stimulants in comparison to a variety of hallucinogens. A previously-reported biphasic pattern of effects of mescaline on shuttle avoidance was replicated and extended to 12 other hallucinogens of both phenylethylamine and indolealkylamine classes. Response patterns of hallucinogens could be differentiated from 3 stimulants and from a methoxyamphetamine compound that lacks hallucinogenic activity.

Amphetamines↗
PubMed1987

Toxicity of MDA (3,4-methylenedioxyamphetamine) considered for relevance to hazards of MDMA (Ecstasy) abuse.

Despite a paucity of data on its animal pharmacology and toxicology, MDMA [Ecstasy, XTC, ADAM; (+/-)-3,4-methylenedioxymethamphetamine] was introduced as an "underground" (FDA-unapproved) adjunct to psychotherapy in the late 1970's and early 1980's, in addition to its use as a recreational drug. Analysis of the limited experimental literature indicates that LD50's for MDMA in five species by several routes of administration tend to predict a significant human toxicity. MDMA was either equally toxic or slightly to moderately less toxic than its close congener, MDA, (+/-)-3,4-methylenedioxyamphetamine. It is suggested that extrapolation of the pharmacologic/toxicologic data available for MDA to MDMA should be assumed to be valid until disproven. Recently published canine data describe physiologic disturbances caused by acute overdosage of MDA, and also indicate the utility of chlorpromazine as an antidote preventing fatalities associated with severe hyperthermia, lactacidemia, hypertension and tachycardia. The toxicology of MDMA warrants further direct study in view of its continuing illegal distribution.

3,4-Methylenedioxyamphetamine↗