Several Years Of Exposure Research Articles

Endocrine characteristics of adolescent menstrual cycles: Impact of early menarche

An initial group of 200 girls, 7–17 years old, was investigated longitudinally 4 times at 1.5-1.5- and 5-year intervals. The present study gives information of the impact of early menarche, a risk factor for breast cancer, on some physical and endocrine characteristics in these subjects. The frequency of ovulation depended significantly on both the time since menarche and the age at menarche. Early menarche was associated with early onset of ovulatory cycles. Even in early puberty, before menarche, the subjects who displayed early menarche during follow-up had higher serum FSH and estradiol concentrations than the girls whose menarche took place after the age of 13.0 years. Adrenal androgen secretion (dehydroepiandrosterone) was not influenced by age at menarche but it increased, as expected, on the basis of chronological age. The group with early menarche was characterized by high circulating estradiol concentrations also after menarche, even in the oldest subjects so far studied, 17–25 years of chronological age. At these ages, the differences in the frequencies of ovulatory cycles were disappearing between the groups formed on the basis of age at menarche. The present findings in pre- and postmenarcheal subjects suggest that the increased risk of breast cancer associated with early menarche is created over several years of exposure to high-level estrogen stimulus.

Vestibular dysfunction in occupational chronic solvent intoxication.

Neurotoxic volatile organic solvents used by house and car painters may lead to professional toxic encephalopathy after several years of exposure. The symptoms are memory impairment, fatigue, personality changes, headache and dizziness. Vestibular dysfunction was found in 55% of 113 painters examined, mainly in the form of reduced caloric vestibular reactions. No correlation between vestibular dysfunction and the duration of exposure, cerebral atrophy or intellectual impairment could be demonstrated. Vestibular examination may be helpful in detecting early changes in exposed persons and in determining more accurate safety limits for harmful chemicals.

Need for Research for Protective Measures Against Chronic Chemical Injury

To the Editor.— In cases of cancer due to industrial chemicals, several years of exposure may occur before any malignant neoplasm can be detected. Our previous studies1-3of patients exposed to solvent vapors indicated damage to the liver and pancreas before a definite increased rate of malignancy was noticed. Recently, increase of angiosarcoma of the liver has been reported among workers in polyvinyl chloride plants, usually after years of exposure. We now have a patient, a 30-yearold man, who has worked for seven years in a polyvinyl chloride plant. For four years, he cleaned tanks used for storing vinyl chloride. He has complained lately of great fatigue. A liver and pancreas scan (Figure) shows his liver to be small, about 1,200 gm instead of the more than 1,500 gm expected for a patient of his height and weight. The inferior edge of the liver shows an irregular concave profile.

Pollen incidence in central Arizona

As to pollen distribution, central Arizona may be divided into two districts: the irrigated valleys with their adjacent fringe of desert, and the mountain country. The Salt River Valley, of which Phoenix is the central point, is taken as a type of the irrigated valleys. Its climatic conditions favor wind-pollinated plants. Species which for the most part are peculiar to the Southwest cause the hay fever and pollen asthma which are prevalent throughout most of the year. In this valley the cottonwood, ash, and olive trees cause mild symptoms in February, March, and April, respectively. Bermuda grass blooms from April 1 to late November, causing intense symptoms. There is no true ragweed in the valley, but members of an allied genus, Franseria, cause two ragweed seasons: the first, in March and April, from the desert franserias; the second, in September and October, from the false ragweed. Various species of Chenopodiales, including careless weed and Russian thistle, cause weed hay fever in summer; careless weed blooms in protected places most of the year. Visitors who are sensitized to the eastern ragweeds are not affected by the franserias unless they are group sensitized. Newcomers who had grass hay fever in the East do not react to the pollen of Bermuda grass until after several years of exposure. Visitors sensitive to pigweed or Russian thistle are not annoyed by pollen of the local species in winter, but they are liable to have symptoms in their first summer. All such group reactors are promptly relieved by intradermal treatment with extracts of the appropriate local pollens. In the mountain towns the hay fever season is relatively brief. Amaranth and Russian thistle in early summer, six-weeks grasses and false ragweed in late summer, account for nearly all cases. Only such visitors as have group sensitization or previous adequate exposure to local pollens are affected. In the resorts located in the pine forest and remote from cultivation, no pollen disease occurs.