High lead exposures resulting from pottery production in a village in Michoacán State, Mexico.

This paper reports findings from a screening study conducted to examine potential lead (Pb) exposures in residents of a Mexican village where Pb oxide continues to be used in ceramic pottery production. Extremely high Pb concentrations were measured in personal and indoor air samples, household surface dust samples, and household soil samples. Personal air Pb concentrations for workers performing pottery firing and glazing were up to 454 microg/m3. Results from indoor air samples indicate that airborne Pb concentrations were lower during nonglazing period compared to the glazing period. Soil Pb concentrations measured in 17 homes ranged from 0.39 to 19.8 mg/g. Dust Pb loading on surfaces of household items, hands, and clothes of a worker ranged from 172 to 33,060 microg/ft2. Pb content as high as 2.4 microg/g was found in a bean stew cooked in a pot made in the village. Based on these Pb concentrations measured in multiple media and data adapted for exposure contact rates, we have made rough estimates of Pb exposures via inhalation, soil/dust ingestion, and food ingestion. Estimated total daily Pb intake, on average, is 4.0 mg for adults and 3.4 mg for children living in the village. In the total daily intake, a greatest fraction may be contributed by food ingestion and another significant fraction may come from soil/dust ingestion for the children. Although the sample size is small, these measurements indicate a very significant public health problem for the village residents and a large number of other similar communities in Mexico. (It was estimated that there are approximately 1.5 million glaze potters.) The Pb exposure is implicated in a number of pervasive health problems in the region, and is the cause for national and international attention. Several recommended solutions to this problem range from personal protection and behavioral changes to introduction of alternative glazes.

Red blood cell membrane dynamics in schizophrenia. II. Fatty acid composition.

Fatty acid compositions were determined in red blood cell (RBC) ghost membranes of schizophrenic patients before and after haloperidol withdrawal, as well as with age-matched normal male control subjects (n = 22). Patients on haloperidol (HD) received treatment in doses between 5 and 20 mg/day for at least 5 weeks (n = 24). Drug-free patients (n = 19) were free of all psychotropic medications for an average of 40 days. A highly significant decrease in the levels (nmol/ml packed RBC) of polyunsaturated fatty acids (PUFAs), particularly 18:2(n - 6) and 20:4(n - 6), was found in both HD-treated and drug-free patients. This decrease remained in those patients who had withdrawn from HD for more than 5 weeks (n = 10). Concomitantly, the percentage of saturated and monoenoic fatty acids to total fatty acids increased significantly in schizophrenic patients. The resultant fatty acid profile consequently lowers the unsaturation index (UI), which represents the average number of double bonds per fatty acid molecule, in RBC ghost membranes of schizophrenic patients. Furthermore, the decreases in UI were significantly correlated to the increases in "structure order" of RBC ghost membranes as measured by the steady-state fluorescence anisotropy (rs) in normal control and drug-free schizophrenic subjects. Therefore, it is likely that decreased levels of PUFAs in schizophrenic patients might result from a defective uptake of 18:2(n - 6) into RBC membrane phospholipids. Since fatty acid composition of membrane phospholipids affects the relative degree of membrane fluidity, the present results lend further support that RBC membrane dynamics are altered in schizophrenia.

Red blood cell membrane dynamics in schizophrenia. III. Correlation of fatty acid abnormalities with clinical measures.

Fatty acid composition was quantitatively analyzed in RBC ghost membranes of 20 schizophrenic patients stabilized with haloperidol (5-20 mg/day) and of the same individuals after haloperdol (HD) withdrawal. The average days on medication and drug-free period were 52 and 40 days, respectively. No significant differences were demonstrated in levels (% or nmol/ml packed RBC) of polyunsaturated fatty acids (PUFAs) between HD-treated and drug-free patients. Similarly, no significant difference was found between relapsed and nonrelapsed schizophrenic patients, although the mean levels of 20:4 (n - 6), total PUFAs or fatty acid unsaturation index (FAUI) were consistently higher in nonrelapsers than in relapsers. On the other hand, the decreases in FAUI were significantly (r = -0.46, p = 0.04) correlated to the increases in psychosis rating which is consistent with our previous reported correlation between altered membrane fluidity and the severity of symptomatology. In addition, decreases in 18:2 (n - 6) but not 20:4 (n - 6) was significantly correlated to the increases in psychosis rating. The present results lend further support that decreased levels of RBC PUFAs in schizophrenic patients lie in an initial stage of PUFAs pathway, possibly a defective uptake of 18:2 (n - 6) into RBC membranes.

Red blood cell membrane dynamics in schizophrenia. I. Membrane fluidity.

Using the fluorescent probe DPH (1,6-diphenyl-1,3,5-hexatriene), steady-state anisotropy (rs) values were determined in red blood cell (RBC) ghost membranes of schizophrenic patients before (n = 26) and after (n = 16) haloperidol withdrawal, and age- and sex-matched normal controls (n = 22). Patients on haloperidol were treated with doses between 5 and 20 mg/day for at least 5 weeks. Drug-free patients had been free of all psychotropic medication for an average of 36 days. The mean rs value of haloperidol-treated patients (0.2422 +/- 0.0076) was not significantly different from that of either the drug-free patients (0.2445 +/- 0.0092) or the normal controls (0.2383 +/- 0.0083). A significant increase (p = 0.037) in rs values, however, was observed in the drug-free schizophrenic patients as compared to that of the controls. Furthermore, the mean rs values of relapsed drug-free patients were significantly (p < 0.05) higher than in the same individuals on haloperidol treatment. Changes in rs values of drug-free patients were also significantly correlated with their increase in psychosis ratings (r = 0.74, p = 0.001). The 'structural order' of RBC ghost membrane, however, was not correlated with age, age of onset, daily haloperidol dose, plasma haloperidol levels, plasma cholesterol concentrations, or the duration of illness, haloperidol treatment or drug-free period. Thus, the present data demonstrate that RBC membrane fluidity is not affected by haloperidol treatment. Following haloperidol withdrawal, however, those patients with decreased RBC membrane fluidity, which correlated with increased psychosis, may be prone to relapse within 6 weeks.

CSF levels of diazepam-binding inhibitor correlate with REM latency in schizophrenia, a pilot study.

CSF diazepam-binding inhibitor-like immunoreactivity (DBI-LI) and polysomnography were studied in 28 drug-free male schizophrenic (DSM-III-R) patients. They underwent a three-night polysomnography evaluation and a lumbar puncture. CSF DBI-LI correlated positively with REM latency, the REM latency/2d nonREM period ratio and stage-4% sleep, and negatively with stage-1% sleep. CSF DBI-LI did not correlate significantly with duration of sleep or sleep latency. CSF DBI-LI during haloperidol treatment did not correlate significantly with sleep EEG measures. The results of this first study of the relationship between endogenous DBI and sleep in humans suggest that physiological effects of DBI other than interactions with the BZD/GABAA receptor complex may explain its positive effects on sleep. However, the absence of similar sleep data in normal subjects precludes us from establishing a specific relationship between DBI and sleep in schizophrenia.

CSF chromogranin A-like immunoreactivity in schizophrenia: relationships with REM latency and slow wave sleep.

Chromogranin A (CgA) is a calcium binding protein and a precursor of modulatory peptides in the brain. We measured CgA-like immunoreactivity (CgA-LI) in cerebrospinal fluid (CSF) in 15 male schizophrenic patients (diagnosed by DSM-III-R criteria) after 3 nights of polysomnography. Patients had been drug free for at least 33 days. Our earlier report that CSF CgA-LI in schizophrenic patients correlated significantly with negative symptoms and ventricle-brain ratios, which have been related to slow wave sleep, raised the possibility that CgA-LI might relate to slow wave sleep. CSF CgA-LI was significantly correlated with stage 4 sleep and rapid eye movement latency. Whether these positive relationships between CSF CgA-LI and electroencephalographic sleep measures are specific for schizophrenia awaits further study.