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Biomedical subjects

C E Ulrich

Publications and source records attributed to C E Ulrich.

34 records · Page 2Linked to original sources
PubMed1979

Pulmonary deposition of aerosols in individual and group caged rats.

There has long been a need to define differences in the amount of aerosol inhaled by group caged rodents as compared to the theoretically ideal individually caged rodent. Therefore, an experiment was designed and conducted to gain insight into this problem. Three groups of animals were evaluated for the degree of pulmonary deposition following a single six hour exposure to a 3 mu aerosol of dodecyl alcohol. One group contained individually caged rats, while the other two groups contained rats caged either in groups of three or seven. Analyzing lungs and trachea for the dodecyl alcohol indicated 25.6 micrograms/g, 27.1 microbrams/g, and 23.1 micrograms/g for rats caged individually, in threes, or in sevens, respectively. There was no statistically significant difference between the amount of dodecyl alcohol found in group caged rat lungs as compared to individually caged rats. Thus group housing does not appear to reduce the amount of aerosol inhaled by rats during a six hour whole body exposure.

Aerosols↗
PubMed1977

Effects in rats and guinea pigs of short-term exposures to sulfuric acid mist, ozone, and their combination.

Ozone and the oxides of sulfur are common environmental pollutants. The acute pulmonary lesions caused by ozone and sulfuric acid mist in rats and guinea pigs have been characterized. Rats are not affected by sulfuric acid mist in concentrations up to 100 mg/m3 except for reduced body weight at the higher doses. A true alveolitis develops in guinea pigs exposed to more than 20 mg/m3 sulfuric acid mist. The ozone lesion is primarily confined to the terminal bronchioles and proximal alveoli. In combination studies with up to 2 ppm ozone and up to 10 mg/m3 sulfuric acid mist, the pulmonary lesion and lung/body weight data were essentially the same as in exposure to ozone alone, and the number of statistically significant synergistic effects in rats and guinea pigs was about what one would expect to observe by chance alone.

Aerosols↗
PubMed1977

Baseline pulmonary physiologic values for the squirrel monkey (Saimiri sciureus).

Baseline pulmonary physiologic values were determined on 43 (421-910 g) male and 47 (425-604 g) female squirrel monkeys (Saimiri sciureus). Respiratory rate was found to be 55 +/- 1.9 (SE) breaths per minute for males and 58 +/- 1.7 breaths per minute for females. Tidal volume was 8.9 +/- 0.37 ml for males and 7.5 +/- 0.28 ml for females. Airway resistance for the male was 0.052 +/- 0.006 cm H2O/ml/second; while for the female it was 0.086 +/- 0.011 cm H2O/ml/second. Dynamic compliance was found to be 1.78 +/- 0.15 ml/cm H2O for males and 1.48 +/- 0.124 ml/cm H2O for females. An index of distribution of ventilation was 48 +/- 2.5 breaths for males and 42 +/- 1.7 breaths for females.

Airway Resistance↗
PubMedDate not supplied

A neurotoxicity assessment of high flash aromatic naphtha.

Catalytic reforming is a refining process that converts naphthenes to aromatics by dehydrogenation to make higher octane gasoline blending components. A portion of this wide-boiling range hydrocarbon stream can be separated by distillation and used for other purposes. One such application is a mixture of predominantly 9-carbon aromatic molecules (C9 Aromatics, primarily isomers of ethyltoluene and trimethylbenzene), which is removed and used as a solvent also known as High Flash Aromatic Naphtha (HFAN). A program was initiated to assess the toxicological properties of HFAN since there may be human exposure, especially in the workplace. The current study was conducted to assess the potential for neurotoxicity in the rat. Adult male Sprague-Dawley rats of approximately 300 grams body weight, in groups of twenty, were exposed by inhalation to HFAN for 90 days at concentrations of 0, 100, 500, and 1500 ppm. During this period the animals were tested monthly for motor activity and in a functional observation battery. After three months of exposure, for 6 hours/day, 5 days/week, 10 animals/group/sex were sacrificed and selected nervous system tissue was examined histopathologically. No signs of neurotoxicity were seen in any of the evaluated parameters, nor was there evidence of pathologic changes in any of the examined tissues.

Administration, Inhalation↗
PubMedDate not supplied

Subchronic inhalation toxicity of nitromethane and 2-nitropropane.

Nitromethane (NM) and 2-nitropropane (2-NP) and versatile compounds employed in a wide variety of industrial applications, thus providing ample opportunity for occupational exposure. The purpose of this study was to determine the subchronic inhalation toxicity of NM and 2-NP in order to recommend acceptable exposure levels in the workplace. Fifty male rats and 15 male rabbits were exposed to either 98 ppm or 745 ppm of NM or 27 or 207 ppm of 2-NP 7 hours/day, 5 days/week, for periods up to 24 weeks. Fifty rats and 15 rabbits were exposed to filtered air for similar lengths of time and served as controls. Ten rats from each exposure and control group were sacrificed following 2 days, 10 days, 1 month, 3 months, and 6 months of exposure. Five rabbits from each exposure or control group were sacrificed at 1, 3, and 6 months of exposure. Effects relatable to exposure to NM were decreased body weight gain in rats following 8 weeks of exposure to 745 ppm, and a thyroid effect evidenced by an increased thyroid weight and decreased serum thyroxin levels, most notable in rabbits. Liver weights were significantly elevated in rats exposed to 207 ppm of 2-NP for 1, 3, and 6 months. No exposure-related gross or microscopic alterations were seen in any of the tissues examined for rats and rabbits exposed to 745 and 98 ppm of NM and 27 ppm of 2-NP or in tissues of rabbits exposed to 207 ppm of 2-NP. Liver neoplasms were seen in all 10 rats killed following 6 months of exposure to 207 ppm of 2-NP, indicating that 2-NP is a potent carcinogen in the rat.

Animals↗