Decrease in luteinizing hormone biological activity/immunoreactivity ratio in elderly men.

Basal serum concentrations of biologically active luteinizing hormone (BIO-LH), immunoreactive LH (RIA-LH) and testosterone (T), as well as the LH bioactivity/immunoreactivity (B/I) ratios were measured in 57 healthy, elderly male volunteers aged 60-94 yr. As a reference group, 53 healthy young men aged 18-49 yr were also studied. LH biological activity was assessed by an in vitro bioassay method based on testosterone production by mechanically dispersed mouse Leydig cell preparations in response to graded doses of LH. The mean BIO-LH and RIA-LH serum concentrations in the elderly men showed a significant increase (two- and three-fold, respectively, P less than 0.001, as compared with the values in the young men, whereas the mean LH B/I ratio and T values were significantly decreased (-22% and -43%, respectively, P less than 0.001). The decrease in the LH B/I ratio in elderly men led us to hypothesize that the ageing pituitary may secrete molecules of LH possessing a reduced bioactivity in relation to their immunoreactivity.

Steadiness of amyotrophic lateral sclerosis in the province of Parma, Italy, 1960-1990.

A clinical and epidemiological study on amyotrophic lateral sclerosis (ALS) was conducted in the province of Parma, Italy, from 1960-1990. A total of 121 cases were collected from hospital records. The average annual incidence was 0.98 per 100,000 inhabitants, with a male/female ratio of 1.1. Age-specific incidence was maximal in the age group 60-69 years. No difference between rural and urban areas was found. Prevalence on October 26th, 1981 was 2.5 per 100,000. Mean age at onset was 60 years, with no significant sex difference. Mean duration of the disease was 30 (sd 21.4) months. Bulbar forms were significantly (p < 0.05) shorter than conventional forms, with a mean duration of 23.4 (sd 21.4) months. Age at onset did not influence prognosis. A comparison of three decades was made, to verify whether possible variations of the disease had occurred with time. From our data a definite stability was found in such epidemiological parameters as incidence, prevalence, mean duration and mortality of ALS in the period.

Hypokalemic thyrotoxic paralysis: a rare cause of tetraparesis with acute onset in Europeans.

We describe a 21-year-old Italian male affected by hypokalemic tetraparesis with acute onset. In the emergency ward, the patient was agitated, with tachycardia (140/min) and systolic hypertension (180/70 mm Hg). He was not able to flex the lower extremities against a light resistance and furthermore, he was hypotonic and without tendon reflexes. One hour later he developed strength deficit of the upper extremities as well. Biochemical analyses revealed severe hypopotassemia (2.1 meg/l). After administration of 140 meq potassium phosphate, the patient began to improve, and 12 h after the onset he was able to walk normally. Successive investigations documented an undiagnosed case of Graves' disease. Thyrotoxic hypokalemic paralysis has been observed almost only in Asians, however, with this case and others reported, we believe that it should be considered as a cause of muscular paralysis also in Caucasians.

Mammary cancer risk: circulating TSH and prolactin, fibrocystic breast disease in chronoepidemiologic perspective.

Classical epidemiology associates human breast cancer with several risk factors including, among others, so-called preclinical hypothyroidism, fibrocystic disease of the breast (FM), and hyperprolactinemia. Relationships among FM, hyperprolactinemia, and thyroid function are of interest because of the possibility of multiple risk combinations. Prolactin and TSH (the latter as a presumed index of preclinical hypothyroidism) undergo rhythmic changes and hence should be chronobiologically investigated. Serum samples obtained at 4-hour intervals throughout a 24-hour span from 23 healthy women and from 25 women with FM (histologically verified) here summarized suggest that circadian mesor-hyperprolactinemia is a feature associated with FM. In a broader context, however, such impressions and an often considered modest impairment of thyroid function in some patients must be viewed in the light of new chronobiologic rules. These include a reciprocity of the circannual amplitudes of TSH and prolactin in relation to breast cancer risk, revealed by cooperative studies. A yet broader chronoepidemiologic view reveals that the reciprocal relation of the circannual amplitudes of circulating TSH and prolactin is (sex) inverted in patients with cancer of the prostate.