Four neuropeptides that inhibit juvenile hormone synthesis by the corpora allata have been isolated from brains of the virgin female cockroach Diploptera punctata. These allatostatins are 8-13 amino acids long, are amidated, and show sequence similarity, including a 3-amino acid sequence at the C-terminal end that is common to all four peptides. The peptide sequences are as follows: allatostatin 1, Ala-Pro-Ser-Gly-Ala-Gln-Arg-Leu-Tyr-Gly-Phe-Gly-Leu-

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Hair mineral analysis from these laboratories was unreliable, and we recommend that health care practitioners refrain from using such analyses to assess individual nutritional status or suspected environmental exposures. Problems with the regulation and certification of these laboratories also should be addressed.

A method is described for the measurement of nanogram or subnanogram amounts of Sn(IV) and the halides of methyltin, dimethyltin, trimethyltin, diethyltin, triethyltin, n-butyltin, din-butyltin, tri-n-butyltin, and phenyltin. These compounds in aqueous solution react with NaBH, to produce volatile hydrides which are detected by atomic absorption spectrometry. The hydrides are separated on the basis of their differing boiling points. Detection limits range from 0.4 ng for Sn(IV) to 2 ng for tri-n-butyltin chloride. Compounds yielding dimethyltin dihydride are found in San Diego Bay seawater at levels of 15 to 45 ng/L, usually exceeding the concentrations of methyltin and inorganic tin. Compounds yielding n-butyltin trihydride and di-n-butyltin dihydride are found in Lake Michigan water at 10-1600 ng/L, also generally higher than the methyl species or inorganic tin. Tin( IV) concentrations are reported for seawater, lake water, marine algae, and sediments from Narragansett Bay.

To assess the impact of elevated levels of inorganic mercury in soil and dust and organic mercury in fish, biological monitoring was conducted among Native Americans living next to an inactive mercury mine in Clear Lake, California. Of resident tribal members, 46% (n = 56) participated in biomonitoring. Urine mercury levels are equivalent to background, indicating that soil and dust exposures among study participants are not substantial. The average blood organic mercury level among study participants is 15.6 +/- 8.8 micrograms/l (n = 44), which is higher than levels reported by others among those who do not consume fish (2 micrograms/l). Consistent with results from other studies, a correlation between fish consumption and blood organic mercury is observed (p = 0.03). The margin between observed and established adverse effect levels for adults is examined for blood organic mercury and found to be less than 10-fold for 20% of the study population. Protective public health efforts for the study population and other similarly exposed populations, notably those who consume commercial fish products, are considered.ImagesFigure 1.

Immunoreactive cytochrome b5 and NADPH-cytochrome P-450 reductase (EC 1.6.2.4) from rat liver microsomal fractions were measured by using an enzyme-linked immunoadsorbent assay (e.l.i.s.a.) as a function of age, sex and type of inducer (phenobarbital or 3-methylcholanthrene), and the values were compared with those obtained by spectral measurement (for cytochrome b5) or enzymic assay (for reductase). In untreated animals, there was more cytochrome b5 and NADPH-cytochrome P-450 reductase when measured by an e.l.i.s.a. than was seen spectrally or enzymically. However, for microsomal preparations from phenobarbital-pretreated animals, spectrally obtained values for cytochrome b5 and immunoreactive-cytochrome b5 values were similar. Values from control animals suggest that there is about 20-30% more immunoreactive cytochrome b5 than that which is spectrally detectable.

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To ass the impc of elraltd level of inooqanic mrcury in soil and dust and oganic mery in fish, b g ngNli eto an inactive mercur min inCer Lae, Calfoni. Ofrsdntia memer, 46% (i-@ 56 atcptdi biomonitong.Urine mercury leelsareequivalent to baclground, indWicatingthat soil anddust ecposures among sudy are not iThe avage blo or ncmeruy lev among sty ip ts is 15.6 * 8.8 pgl (n = 44), which is highr than leves reported by others among those who do not consme fish (2 lg/l). C it with results fiom other studies, a on between fish consumption d blood orgnic mercury is observed (p-0.03). The margin between observed and adver effectlevs for adults is e for blood organic mercu iand f to be less than 10-fold for 10% of the study Protecive public health &effot for the study pop on and others lary ex popuions, notably those who consume commerial fih products, are considered. we contaminated soil, fish advisories, fish consumpion, inorgnic mercury, methyl mercury, Native Amercans.