Do questions about lead exposure predict elevated lead levels?

OBJECTIVE: To assess the usefulness of the lead poisoning questionnaire developed by the Centers for Disease Control and Prevention as a screening tool for elevated lead levels. METHODS: This descriptive study used a five-question questionnaire at our hospital-based general pediatric clinic and in two local private practices. We obtained venous lead levels from 485 children aged 9 months to 6 years who were brought for health supervision visits. The questionnaire was completed by a primary caretaker of 330 patients (68%). Contingency tables were used to compare lead levels with the responses on the questionnaire. RESULTS: Lead levels of > or = 10 micrograms/dL were found in 23 (7%) of 330 who completed the questionnaire. Caretakers of children with elevated lead levels were more likely to answer yes to questions about chipping paint and home remodeling than those whose children had levels < 10 (P = .0001). These questions had sensitivities for detecting elevated lead levels of 70% and 74% with negative predictive values of 97% and 98%, respectively. Questions about known contacts with lead poisoning and job or industrial exposure to lead each had sensitivities of < 10%. The Centers for Disease Control and Prevention's definition of high risk for lead poisoning (one or more positive responses) was nearly 90% sensitive for detecting elevated lead levels with a negative predictive value of 99%. CONCLUSION: This risk assessment questionnaire is an effective screening method for elevated lead levels in our population. Questions about the home environment were more sensitive indicators of elevated lead levels than other standard high-risk questions.

Benzodiazepine suppression of corticotropin-releasing factor (CRF)-induced beta-endorphin release from rat neurointermediate pituitary.

Dopamine and gamma-aminobutyric acid (GABA) inhibit POMC peptide release from the pituitary intermediate lobe, via interaction with D2 or GABA-A/benzodiazepine receptors. Here, we examined the effects of an antianxiety triazolobenzodiazepine, adinazolam, on corticotropin-releasing factor (CRF)-stimulated POMC peptide secretion from the rat neurointermediate pituitary. Neurointermediate lobes (NILS) were incubated with CRF (10(-7) M), then adinazolam (10(-8) or (10(-9) M) was added, with CRF remaining in the medium. Aliquots were removed at 15-min intervals and frozen for radioimmunoassay of beta-endorphin. Adinazolam alone did not significantly affect secretion as compared to controls or CRF alone. Adinazolam incubated with CRF led to significant inhibition of beta-endorphin secretion, as compared to CRF alone. In addition, adinazolam was as effective as dopamine or the CRF antagonist, alpha-helical CRF, in preventing CRF-induced beta-endorphin release. Adinazolam appears to act directly on the pituitary to suppress hormone release induced by a stress-related hypothalamic peptide.

Effects of the enkephalin analog (D-Met2,Pro5)-enkephalinamide on alpha-melanocyte-stimulating hormone secretion.

We used the met-enkephalin analog (D-Met2,Pro5)-enkephalinamide (DMPEA) to investigate enkephalinergic control of alpha-melanocyte-stimulating hormone (alpha-MSH) secretion. Systemic (s.c.) administration of DMPEA elevated plasma titers of alpha-MSH in a dose- and time-related manner. Pretreatment with the opiate antagonist naltrexone had no effect on basal plasma levels of alpha-MSH but blocked DMPEA-induced alpha-MSH release. Treatment with a dose of naltrexone sufficient to block DMPEA-induced secretion of alpha-MSH had no effect on stress-induced secretion of alpha-MSH. Although pretreatment with the dopamine receptor agonist apomorphine prevented DMPEA-induced alpha-MSH secretion, DMPEA had no effect on the synthetic activity of tuberohypophysial dopamine neurons as gauged by measuring the accumulation of 3,4-dihydroxyphenylalanine in the neurointermediate lobe (NIL) following administration of NSD-1015. In vitro treatment of isolated NILs with DMPEA resulted in a significant increase in alpha-MSH release. Naltrexone completely blocked the stimulatory effects of DMPEA on alpha-MSH release in vitro. Our results indicate that DMPEA stimulates alpha-MSH secretion by acting directly through opiate receptors at the level of the NIL.

Interaction of corticotropin-releasing factor (CRF) and alpha-helical CRF on rat neurointermediate lobes: in vitro studies.

Neurointermediate lobes (NILS) of the pituitary glands of adult male Sprague-Dawley rats were incubated in media in the presence of corticotropin-releasing factor (CRF), a stimulator of proopiomelanocortin (POMC) peptide release. Alpha-helical CRF, a peptide known to inhibit CRF induced POMC peptide release from the anterior pituitary, was incubated with NILS for a period of 90 min, to study its potential ability to modulate peptide release from the intermediate lobe. The alpha-helical peptide reduced beta-endorphin release from NILS, as measured by radioimmunoassay (RIA), when added for the entire incubation, or when added 30 min after start of the incubation period, with CRF present. Alpha-helical CRF alone reduced beta-endorphin release, as compared to control or CRF-treated lobes. Ultrastructural examination of intermediate lobes fixed at the end of incubations revealed a reduction in the numbers of Golgi-associated dense granules, an indicator of new peptide synthesis, in intermediate lobe tissue treated with alpha-helical CRF alone, both peptides together, or with CRF followed by alpha-helical peptide. The in vitro studies demonstrate the effectiveness of the antagonist peptide on intermediate lobe peptide secretion, thereby extending its effects to both POMC-secreting areas of the pituitary gland.

Degeneration and regeneration of nerve terminals in the rat pituitary pars intermedia after 6-hydroxydopamine treatment.

6-hydroxydopamine (6-OHDA), a catecholamine neurotoxin, has been shown previously to induce degenerative changes in nerve terminals innervating proopiomelanocortin (POMC) cells of the pituitary intermediate lobe. The present study provides evidence for regeneration of nerve fibers to the pituitary within 4 weeks of drug treatment. Adult male Sprague-Dawley rats were treated with 6-hydroxydopamine (150 mg/kg) on Days 1 and 3 and then perfused for light or electron microscopy (EM) of the pituitary intermediate lobes at 1, 2, 3, or 4 weeks after the first injection. At 1, 2, and 3 weeks after drug treatment, the number of normal-appearing nerve terminals was significantly lower than that in controls, while at 4 weeks after 6-OHDA, the number of normal nerve terminals did not differ significantly from that of control rats. Tyrosine hydroxylase-immunoreactive fibers appeared more intensely stained at 1 and 2 weeks after 6-OHDA treatment, suggesting continued and perhaps enhanced synthesis of the enzyme by hypothalamic cell bodies to the remaining terminals. Serotonin immunoreactivity after 5-hydroxytryptophan pretreatment was not detectable at 1 week after drug treatment, but was clearly visible in fibers innervating the intermediate lobe at 3 weeks, indicating a return of uptake ability and conversion of the precursor to serotonin by the regenerating terminals. Chemical denervation of the intermediate lobe followed by regeneration of nerve fibers will be useful for examination of regulatory mechanisms for the POMC secretory cells.

An instrument to measure musculoskeletal symptoms among immigrant Hispanic farmworkers: validation in the nursery industry.

We report on the construction and psychometrics of a survey measure of musculoskeletal symptomatology for use with Spanish-speaking immigrant farmworkers. Survey development included focus groups with workers, forward and backward translations, and pilot testing. The final survey includes a body diagram and items about symptom severity, frequency, and duration and about self-treatment, medical care, and job tasks. We report on the initial test of the survey with 213 commercial nursery workers in Southern California. Fifty-five percent of the workers reported pain, with 30% reporting back pain, 21% reporting upper extremity pain, 19% reporting lower extremity pain, and 10% reporting neck and shoulder pain. A composite symptom score exhibited acceptable test-retest reliability (r = 0.41, p < 0.01) over the annual agricultural cycle. Greater symptomatology was associated with greater frequency of self-treatment (r = 0.42, p < 0.01), seeking professional health care (t = 2.49, p < 0.05), and exposure to high-risk jobs (OR = 2.1, p < 0.05, CI = 1.0 to 4.4), supporting the validity of composite score.