Physiological response to aerosol propellants.

Acute exposures to isobutane, propane, F-12, and F-11 in concentrations of 250, 500, or 1000 ppm for periods of 1 min to 8 hr did not produce any untoward physiological effects as determined by the methods employed which included serial EKG's and continuous monitoring of modified V5 by telemetry during exposure. Repetitive exposures to these four propellants were also without measurable untoward physiological effect with the exception of the eight male subjects repetitively exposed to 1000 ppm, F-11, who did show minor decrements in several of the cognitive tests. Of particular importance is the observation that none of the subjects showed any decrement in pulmonary function or alteration in cardiac rhythm as the result of exposure to concentrations of the gases or vapors far greater than encountered in the normal use of aerosol products in the home.

Airway response to hair spray in normal subjects and subjects with hyperreactive airways.

Short-term 20-second exposure to hair sprays A and B failed to show significant decreases in maximum expiratory flow rates at low pulmonary volumes in normal subjects; however, significant decreases were observed with hair spray B in eight subjects with hyperractive airways (abnormal response to inhalation of methacholine). On the partial flow-volume curves, flows at 40 percent and 25 percent of forced vital capacity decreased 8.9 to 10.3 percent and 14 to 18.7 percent, respectively. The hair sprays differed in their content of perfume and plasticizer, and since the latter is generally considered nontoxic at room temperature, the perfume may be the responsible agent. It would appear from this study that normal healthy individuals are at little risk, at least from brief exposure to hair spray; however, in the presence of hyperreactive airways, as seen in asthmatic subjects and in some people with allergic rhinitis and viral respiratory infections, an immediate response of the airways may result from exposure to some hair sprays.

Acute and repetitive human exposure to isobutane.

Eight adult volunteers of both sexes were exposed to isobutane in a controlled-environment chamber for the purpose of monitoring their physiological responses to a series of gas concentrations ranging from 250 to 1,000 ppm. First, the response to exposure periods of 1 min, 2 min, 1 h, 2 h, and 8 h were studied. There being no untoward responses to these acute exposures, the eight volunteers were exposed repetitively to isobutane at concentrations of 500 ppm, 1, 2 or 8 h per day, five days per week for two weeks. Then exposures to two mixtures of isobutane and propane for 1, 2 or 8 h per day for two days were studied. During the investigation all subjects were kept under comprehensive medical surveillance. No untoward subjective responses or abnormal physiological responses occurred during or following these exposures. Special emphasis was placed on evaluating the cardiac and pulmonary response to these exposures through the use of continuous ECG telemetry and serial computerized spirometric measurements. The following serial laboratory studies were unaltered by the exposures: complete blood count, urinalysis, serum alkaline phosphatase, SGOT, LDH, serum bilirubin, blood sugar, serum calcium, serum phosphorus, BUN, spontaneous electroencephalogram, visual evoked response, a battery of cognitive tests, and an ACTH stimulation test.

Early immunization of neonates with trivalent oral poliovirus vaccine.

Described is the evaluation in Brazil of the immune response of early immunization with trivalent oral poliovirus vaccine (TOPV). A total of 85 normal neonates from São Paulo were assigned one of the following immunization schedules: group A--one dose of TOPV at birth and subsequent doses at 2, 4, and 9 months of age; or group B--one dose of TOPV at 2, 4 and 6 months of age. Blood samples were collected sequentially from the mother at delivery, from the umbilical cord, and from the child at 2, 4, 6, 9 and 12 months of age for assay of poliovirus neutralizing antibodies. Administration of TOPV at birth, in addition to establishing immunity against poliomyelitis at an earlier stage, produced a superior immune response to poliovirus type 3. At the end of the first year, the proportion of susceptible individuals was 3.7% in group A and 25.9% in group B. When immunization against poliomyelitis is started at birth, excellent seroconversion rates are obtained from the third dose onward.