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Biomedical subjects

H N MacFarland

Publications and source records attributed to H N MacFarland.

16 recordsLinked to original sources
PubMed1978

A three month inhalation toxicity study in the squirrel monkey (Saimiri sciureus) with terbutaline sulfate (Bricanyl).

A study of the subacute toxicity of inhaled terbutaline sulfate was performed in the Squirrel monkey (Saimiri sciureus). 3 groups of monkeys were exposed 1 h daily 7 days/week for 3 months to terbutaline sulfate aerosols at concentrations of 0.039, 0.185 and 0.799 mg terbutaline/litre of air respectively. A fourth group was a chamber control receiving air only. The following clinical parameters were evaluated: physical appearance and behavior, weight gain, ophthalmoscopic appearance, electrocardiograms, hemograms, blood biochemical profiles and urinalyses. At termination necropsies were conducted and organ weights determined. A variety of staining techniques was employed in the histopathological examination of tissues. Special attention was given to heart and lung. The distribution of goblet cells in sections from the main bronchi and trachea was also investigated. Occasionally a few animals in both the intermediate and high dose groups showed small amounts of exudate and frothing around the mouth during exposure to their respective terbutaline aerosols. No other changes that could be attributed to the exposure to terbutaline aerosols were seen in any parameter.

Aerosols↗
PubMed1975

Inhalation studies of nickel sulfide in pulmonary carcinogenesis of rats.

Two hundred twenty-six specific pathogenfree male and female F344 rats were exposed to nickel sulfide inhalations for 78 weeks (5 days/wk, 6 hr/day) and observed for an adiditional 30-week period. For the same amount of time, 214 rats were exposed to filtered room air and served as controls. Rats exposed to nickel sulfide showed a significantly higher incidence of pulmonary hyperplastic and neoplastic lesions originating from the bronchial and bronchiloo-alveloar segments. The overall incidence of lung tumors in the animals treated with nickel sulfide was 14 percent compared with 1 percent in the controls. Pulmonary inflammatory reactions were also greatly increased. Injection of an agent (hexachlorotetra-fluorobutane) that induced lung infarction did not increase the proportion of animals having lesions, nor did it alter the type of lesions found in animals exposed to nickel sulfide.

Animals↗
PubMed1975

Inhalation toxicology.

Two kinds of problems associated with developing standardized procedures for the safety evaluation of new compounds are identified. The first of these is the question of the desirability of using such standard methods. It is concluded that a basic set of procedures is to be recommended, but this should be supplemented with special tests as may be indicated. The second problem is connected with the technical difficulties of any given type of assay and is normally dealt with in terms of the state of the art at the time. Assays by the inhalation route tend to be custom designed and do not follow standard protocols. One of the causes of this situation is the propensity of individual investigators to design de novo the equipment used to effect exposure of animals to airborne substances. Second, some confusion exists because investigators do not always appreciate that the concentration-time product is not the same as the true dose received by the exposed subjects and this may lead to anomalies when dose-response relationships are being characterized. It is suggested that interlaboratory studies be undertaken to ascertain the variability that might be expected in independent assays of inhalation toxicity.

Aerosol Propellants↗
PubMedDate not supplied

Designs and operational characteristics of inhalation exposure equipment--a review.

The development of equipment for use in the experimental study of the effects of inhalable airborne materials has been reviewed. Reference is made to early descriptions of apparatus employed in the mid-nineteenth century up to the present conventional stainless steel and glass units. Whole body chambers, head only arrangements and face mask devices are described. Factors governing the operational characteristics of chambers when utilized in the static or dynamic mode are discussed. The question of uniformity of distribution of the airborne agent in chamber atmospheres has been examined at some length. It is concluded that unusual arrangements to improve distribution are ineffective or produce only marginal improvements. In addition, brief reference has been made to a number of special areas of investigation and to certain considerations of interest to the operator of inhalation equipment. A list of useful reviews and monographs is provided.

Air Pollutants↗
PubMedDate not supplied

Toxicology of petroleum hydrocarbons.

Before discussing the toxicologic effects of petroleum hydrocarbons, the author reviews the considerable resources available today to investigators in this area. He then covers the toxicology of the major classes of petroleum hydrocarbons, including aliphatic, alicyclic and aromatic compounds.

Animals↗