Respiratory diseases and allergies in two polluted areas in East Germany.

This cross-sectional epidemiological study collected health data for 2,470 school children between 5 and 14 years of age (89% of eligible children) who had lived most of their lives in either one of two counties strongly impacted by industrial pollution (Bitterfeld and Hettstedt) or in a neighboring county without any sources of industrial pollution (Zerbst). The objective of the study was to examine whether regional differences--with respect to the occurrence of childhood respiratory diseases and symptoms or allergies--exist and, if such differences are found, whether they persist when we adjust for the effects of known risk factors such as medical and sociodemographic factors or factors related to the indoor environment. Controlling for medical, sociodemographic, and indoor factors, according to parental reports, children residing in Hettstedt have about a 50% increased lifetime prevalence for physician-diagnosed allergies, eczema, and bronchitis compared to children from Zerbst and about twice the number of respiratory symptoms such as wheeze, shortness of breath, and cough without cold. Sensitization to common aeroallergens according to skin prick tests [odds ratio (OR) = 1.38; 95% confidence interval (CI), 1.02-1.86] and specific IgE levels (OR = 1.75; CI, 1.31-2.33) was more common for children from Hettstedt than children from the nonpolluted county. Bitterfeld children, on the other hand, more often received a diagnosis of asthma and eczema than children residing in Zerbst and also showed slightly increased sensitization rates. In conclusion, industrial pollution related to mining and smelting operations in the county of Hettstedt were associated with a higher lifetime prevalence of respiratory disorders and an increased rate of allergic sensitization in children between the ages of 5 and 14 years. Further studies are needed to determine what role the high dust content of heavy metals plays in Hettstedt.

A more extensive study of the effects of high doses of ICI 118630 and of 3 other LH-RH agonist analogues on the plasma levels of several hormones in rats was undertaken, together with an examination of the effects on some endocrine target organs. This work was performed in conjunction with an evaluation of the effectiveness of such LH-RH analogues in causing regression of dimethylbenz(a)anthracene (DMBA)-induced mammary tumours in the rat, the results of which are reported in the accompanying paper (Nicholson & Maynard, 1978).

MATERIALS AND METHODS
Peptides.-The 4 peptides (Table I) used in these studies were synthesized by solution methods (Dutta et al., 1978b) by Dr A. S. Dutta, ICI Pharmaceuticals Division, Macclesfield, England. The purity of each peptide wvas >95%o, as assessed by thin-layer chromatography, paper electrophoresis and amino-acid analysis.
Animnals. Mature virgin female Sprague-Dawley rats bred in the Institute were used throughout the study. The animals were housed in a 12 h light/12 h dark environment and had access to feed and wN-ater ad lib.
The peptides were dissolved in physiological saline and administered as an i.m. injection (100 [L) into the rear legs of the rats, betwAeen 09.00 and 10.00 and also, when twice-daily injections wvere made, between 15.30 and 16.30.
When animals were to be killed, blood samples were obtained after decapitation or via the dorsal aorta under ether anaesthesia. If recovery of the rat was desired, small samples of blood (up to 2 ml) were taken from one of the jugular veins. Organ weights were expressed as a fraction of the total body weight of the animal at the start of the experiment.
Plasma hormone assays.-Oestradiol was measured in non-chromatographed ether extracts of the plasmas, using a radioimmunoassay technique. The antiserum was raised in rabbits against oestradiol linked to bovine serum albumin through the 6 position. The assay had a cross-reaction of less than 1% with other common oestrogens and C09steroids, and had a sensitivity of 1-7 pg.
The protein hormones LH and FSH were measured by a double-antibody radioimmunoassay procedure similar to that described by Groom (1977) for human pituitary hormones, but using materials contained in kits obtained from NIH.

RESULTS
The temporal effects on plasma LH levels of a single injection of 5.0 ,ug of one compound, ICI 118630, were examined ( Fig. 1). There was a rapid increase in immunologically reactive LH in the plasma which reached peak concentration at 1-2 h after administration of the LH-RH analogue. Plasma concentration of LH had fallen considerably, but not to basal values, 6-8 h after the injection.
Since the biological effects of similar compounds were usually most noticeable after twice-daily administration, the plasma LH profile was obtained on this regime (Fig. 2). The second injection (also of 5-0 pg) given 7 h after the first, again caused a peak of LH in the plasma after about 1-2 h, though the second peak was not as high as the first. By the following morning plasma LH concentration was indistinguishable from control.
A similar pattern of plasma LH release was found after 14 days of twice-daily injection of 5 0 Hg ICI 118630 (Fig. 3), although the levels of LH and the quantity released were considerably lower than on the first day of treatment. The effect on intact female animals of 2 dose levels of each analogue was examined after 14 days of treatment, the doses being 5-0 pg and 0-5 ,g per injection given twice daily. Table II shows the plasma hormone concentrations in the various groups; blood was taken after decapitation without anaesthesia 1 h after the final injection. All treatment groups and ovariectomized animals showed a significant (P<0-5, Mann-Whitney U test) elevation of LH levels over controls, and many of the animals receiving LH-RH analogues had higher LH concentrations than ovariectomized rats.
The synthetic analogues also raised  agonist analogues, comnpared with saline-treated control and ovariectomized animals.
It is also clear from Table II that administration of either dose level of the LH-RH analogues reduced circulating oestradiol concentrations to those in ovariectomized rats. Vaginal smears taken at necropsy showed many more of the treated rats than controls were in dioestrus. Table III shows the effects of the LH-RH analogues on the weight of several organs in the animals compared with those of control and ovariectomized groups. All the compounds caused a slightly higher total weight gain than the controls, which was comparable to that produced by ovariectomy. Kidney weights were always similar to the control animals, but adrenal and pituitary weights were reduced, again to an extent similar to that in ovariectomized animals. All the syn-thetic LH-RH analogues caused a small decrease in ovarian weight, particularly at the higher dose levels, but the most marked effect was on the uterus. Compounds ICI 118630 and ICI 115605 both caused a decrease in uterine weight to values indistinguishable from those of ovariectomized animals. Compounds ICI 123220 and ICI 123215 caused a decrease in uterine weight but, particularly at the lower dose level, not as dramatically as ovariectomy.
Because 0 5 [kg ICI 118630 reduces plasma oestradiol and uterine weight, a lower dose level was evaluated: 0-05 [kg twice daily. A further group of animals was treated in an identical manner and the results are given in Tables II and III. The LH levels were similar to those in animals given higher doses, but there was not such a dramatic decrease in plasma oestradiol or in uterine weight. No dif-

DISCUSSION
The effect of LH-RH agonists of inhibiting HCG-induced uterine growth when administered at high doses (Rippel & Johnson, 1976;Dutta et al., 1978a) prompted a more detailed investigation into the biological results of such treatment with LH-RH agonists containing the AzglylO modification. From studies of the time course of plasma LH levels after injection of ICI 118630 (Figs. 1-3) it is clear that it is indeed an extremely potent LH-RH agonist. Even after 14 days of continuous administration, it elicits a marked and extended release ofLH.
Nevertheless, all these analogues do reduce plasma oestradiol levels considerably (Table II), and the effects on organ weights (Table III) are consistent with this finding. In this respect, ICI 118630, with an AzglylO residue, is more effective at causing a decrease in uterine weight in intact female rats than a similar compound with a Proethylamide9 C-terminal grouping (ICI 123215) (see Table III).
It is apparent that this effect is dose dependent, since the twice-daily administration of 0 05 tg of ICI 118630 did not cause as great a decrease in uterine weight as higher dose levels, nor were oestradiol concentrations reduced so markedly, despite levels of LH being equally high 1 h after injection.
The mechanism whereby injection of LH-RH analogues can greatly elevate plasma LH levels and yet cause a reduction in plasma oestradiol (Table II) is not fully understood. There are, however, a number of theoretical explanations for this phenomenon. Firstly, it is possible that the LH-RH analogue may have a direct effect on the ovary, rendering it incapable of responding, by increased steroidogenesis, to LH stimulation. Secondly, the production of extremely high levels of circulating LH may block the physiological action of LH at the ovary and inhibit synthesis of the LH receptor (Zor et al., 1972). Thirdly, it is possible that continued overstimulation of the pituitary may cause the production of immunologically reactive LH with no biological activity.
These effects could have a practical application in certain clinical situations. For example, hormone-dependent metastatic breast cancer in premenopausal women may possibly be treated by such a chemical oophorectomy. Moreover, women who are most likely to respond to surgical castration might be selected after a short course of treatment with an LH-RH agonist.