1188 We consider that the activation and release of trypanosome and lysophospholipases in infected animals may account for several major features of the pathology of try-

phospholipases

panosomiasis. A.R.C Institute for Research on Animal Diseases, Compton, Newbury, Berkshire RG16 0NN

Department of Veterinary Microbiology and Immunology, University of Guelph, Guelph, Ontario, Canada Department of Chemistry, University of Guelph Department of Veterinary Preventive Medicine, University of Liverpool

C.

J. ROBERTS

I. R. TIZARD A. MELLORS

M.

J. CLARKSON

Furthermore the slopes of the regression lines were small. An increment of water lead concentration from 50 to 500 µg/1 increased the blood-lead in mother and baby by about 3 µg/d1 and in placenta by about 25 ng/g (wet weight). The similar influence of lead in water on blood-lead of mother and newborn confirms the rapid transfer of lead from mother to fetus,3 and the strong positive correlation (r = 0.86) between maternal and cord blood lead confirms our previous finding.3 Thus

although drinking water does not seem to contribute greatly to lead exposure, our results do emphasise the need to avoid lead contamination during pregnancy. R. LAUWERYS G. HUBERMONT Medical and Industrial Toxicology Unit, J. P. BUCHET University of Louvain, H. ROELS 1200 Brussels, Belgium

DOMESTIC WATER AND LEAD EXPOSURE DURING PREGNANCY

COMMUNICATING HYDROCEPHALUS

SIR The contribution that lead in domestic water makes to lead exposure is controversial. In Glasgow the increased lead levels found in older houses were associated with significantly raised blood-lead concentrations in the occupants,’ while in north-west Wales water was not found to be an important source of lead exposure.2 Since lead is transferred from mother to fetus3 and since excessive exposure to lead in utero has been suggested as a factor in the aetiology of mental retardation4 we need to know whether consumption of lead contaminated water by pregnant women can influence fetal exposure to the metal. water

INFLUENCE

OF WATER LEAD ON LEAD CONCENTRATION IN BLOOD AND PLACENTA

SiR,-Your editorial of Nov. 12, (p. 1011) contains

an

The corpus callosum angle in these cases has been reported’ to be less than 120° not greater than 120°, as stated in the editorial. The observation of corpus callosum angles of less than 120°does not seem to be a reliable predictor of reserror.

ponse to shunting, however.2 Department of Neurology, Albert Einstein College of Medicine of Yeshiva University, Bronx, N.Y. 10461, U.S.A.

ROBERT P. FRIEDLAND

EXOGENOUS ŒSTROGENS AND OVARIAN CANCER A SERIOUs error by The Lancet’s printers totally obscured the meaning of the second paragraph of the letter by Dr John F. Annegers, Dr William O’Fallon, and Dr Leonard T. Kurland (Oct. 22, p. 869). With apologies to Dr Annegers and his colleagues and to our readers we reproduce this paragraph in full as it should have appeared. "Hoover et al. reported 8 cases of ovarian cancer in an

oestrogen-exposed cohort where the expected number was 3.3 (relative risk 2.4, 95% confidence interval 10-44). All of the patients were at risk of ovarian cancer in that they had at least

follow-up were terminated if an underwent patient oophorectomy. Thus only personyears in which patients were at risk (i.e., having an intact ovary) were considered. The rates which they applied to these person-years were obtained from the total population, including those not at risk of ovarian cancer. We do not know the prevalence-rates of bilateral oophorectomy in the populations served by the three tumour registries whose incidence-rates were used by Hoover et al. However, in Rochester, Minnesota, about 10% of the female population over 45 are without ovaries and are thus not at risk of ovarian cancer. If a similar rate applies in the three populations used by Hoover et al. the expected numbers they obtained are about 11% too low. An 11 % increase in the expected numbers given in their table I reduces the lower bound of the 95% confidence interval to 0.9 in two of the three comparisons. The data reported by Hoover et al. do not point as strongly to an increased risk of ovarian cancer with exogenous oestrogen use as they suggest." one

*(A) water lead 50

ug/1 (n=29).

A random

sample of 70 pregnant women was drawn from maternity home in Libramont, a rural area in the south of Belgium in which some houses have high levels of water lead. a

All the mothers had lived in the year before delivery. Tap water

house for more than one first run-off in the morning) was obtained from the homes and, at delivery, bloodsamples were taken from the mother and from the umbilical cord. A fragment of placenta was also collected. 42% of the water samples contained lead above the proposed W.H.O. drinking-water standard of 50 µg/1 but most of the concentrations were below 600 µg/1 (see table). The mothers were divided into two groups: group A had water below the W.H.O. standard, and group B had water above this value. Significant group differences in lead concentrations for maternal and cord blood and for placenta were found (see table). Although the differences in lead concentrations were small, there were highly significant curvilinear correlations between water lead and lead concentration in blood (mother, newborn) or placenta (P

Domestic water and lead exposure during pregnancy.

1188 We consider that the activation and release of trypanosome and lysophospholipases in infected animals may account for several major features of t...
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