In vivo measurements of bone lead content in residents of southern Ontario.

In 111 subjects not occupationally exposed, bone lead content increased steadily with age in both men and women. Higher than expected bone lead levels were observed in two-thirds of 27 subjects working in occupations with potential for lead exposure. Five of 8 patients who displayed symptoms which might have been due to lead poisoning had increased bone lead levels.

Chlorinated hydrocarbon contaminants in arctic marine mammals.

By 1976, the presence of chlorinated hydrocarbon contaminants (CHCs) had been demonstrated in fur seal (Callorhinus ursinus), ringed seal (Phoca hispida), hooded seal (Cystophora cristata), bearded seal (Erignathus barbatus), walrus (Obdobenus rosmarus divergens), beluga (Delphinapterus leucas), porpoise (Phocoena phocoena) and polar bear (Ursus maritimus) in various parts of the Arctic. In spite of this early interest, very little subsequent research on contaminants in Arctic marine mammals was undertaken until the mid-1980s. Since that time, there has been an explosion of interest, resulting in a much expanded data base on contaminants in Arctic marine mammals.

Bioconcentration of superlipophilic persistent chemicals : Octachlorodibenzo-p-dioxin (OCDD) in fish.

According to present understanding, persistent superlipophilic chemicals - such as octachlorodibenzo-p-dioxin, octachlorodibenzofuran, Mirex etc - with log Kow > 6 and cross sections > 9.5 Å, bioconcentrate in aquatic organisms only little from ambient water. The most convincing argument against it is that in bioconcentration experiments with superlipophilic chemicals amounts applied exceeded water solubility by several orders of magnitude.

Metalloproteinase-dependent neurite outgrowth within a synthetic extracellular matrix is induced by nerve growth factor.

In order to assess the requirement for matrix metalloproteinases in neuronal regeneration, in vitro neurite outgrowth by chick dorsal root ganglionic neurons (DRGn) was examined within a reconstituted extracellular matrix. For these studies, cultured neurons were treated with a synthetic peptide inhibitor of metalloproteinases (spIMP), LMHKPRCGVPDVGG. spIMP inhibited all neuronal metalloproteinase activities in zymography and substrate-release assays and was used to examine the role of metalloproteinases in neurite outgrowth by DRGn.

Cancer of the respiratory tract in nickel sinter plant workers: effect of removal from sinter plant exposure.

The risk of death due to cancer of the nose or lung was studied in nickel sinter plant workers during the period after they left the sintering operations. It was found that the excess risk of death from both diseases continued for many years after leaving the sinter plant. No effect of age at first exposure could be found.

Colored aftereffects contingent upon global transformations?

Dodwell and Humphrey (Psychol. Rev. 97, 78-79, 1990) have argued that colored aftereffects (CAEs) are contingent on the global geometries of local orientation and edge components in induction patterns.

Pattern and space perception in young infants.

Research is reviewed which reveals the surprisingly advanced perceptual skills of very young infants and some changes in these capacities which occur early in life; possible mechanisms which may underlie these changes are discussed. Newborns readily turn toward visual, auditory, and tactual stimulation, indicating that primitive localization systems operate at birth. However, their pattern perception appears to be more limited, with the notable exception of certain facial configurations which may have a privileged status.

Inuit exposure to organochlorines through the aquatic food chain in arctic québec.

Inuit people (Eskimos) are likely exposed to persistent organochlorine compounds because their traditional diet includes fatty tissues of the arctic marine biota. Here we present the results of organochlorine compound analysis in milk fat samples from arctic Québec Inuit women and in fat tissues from various animal species inhabiting that region. The total concentration of polychlorinated biphenyl congeners in Inuit milk fat was similar to that of the beluga, while the profile of the 10 congeners resembled that of the polar bear.

Neonatal movement response decrement and recovery to sounds as a function of stimulus intensity.

Response decrement, novelty response, and dishabituation of body movements to repeated presentations of a white noise stimulus of 66, 76, and 86 dB were studied in 89, 2-3-day-olds in the first epoch of active-quiet sleep following a feeding. Newborns receiving the 86 dB repeating stimulus had greater movement scores compared to those receiving the 76 dB intensity who, in turn, had greater movement scores than those receiving the 66 dB intensity. All groups demonstrated movement response decline following repeated stimulation and a novelty response was observed when either a 66 or 76 dB repeating stimulus was increased to 86 dB.

Molecular epidemiology of Cladosporium carrionii.

Mitochondrial DNA (mtDNA) diversity was investigated in 38 isolants of Cladosporium carrionii in Africa (3 isolants), Australia (10), China (15) and Venezuela (10). C. carrionii was classified into 4 mtDNA types (Type I to Type IV) based on the restriction patterns with MspI, Sau3AI and HaeIII.

Quantitative methods for scoring cell migration and invasion in filter-based assays.

The ability of cells to traverse pores in a biocompatible filter provides means for examining cell chemoattraction. Filter-based assays also permit rapid, quantitative assessment of the in vitro migratory and invasive potential of tumor cells. Scoring migration has relied on visual counting of stained cells which appear on the underside of the filter and determining a true percentage score involves arduous counting of cells on both filter surfaces.

Is visually guided reaching in early infancy a myth?

The issue examined was whether infants require sight of their hand when first beginning to reach for, contact, and grasp objects. 7 infants were repeatedly tested between 6 and 25 weeks of age. Each session consisted of 8 trials of objects presented in the light and 8 trials of glowing or sounding objects in complete darkness.

Classification of radiographs for pneumoconiosis: the Canadian Pneumoconiosis Reading Panel.

A method of providing experience for readers in the classification of radiographs for pneumoconiosis is described. It is based on an exchange of films by mail, with provision for ongoing feedback of results. The effects of this feedback on reading levels is described.

Occupational dust exposure and chronic obstructive pulmonary disease. A systematic overview of the evidence.

The object of this study was to assess the relationship between occupational dust exposure and chronic obstructive pulmonary disease (COPD). Studies were identified using MEDLINE (January 1966 to July 1991), SCISEARCH, manual review of reference lists, and personal contact with more than 30 international experts. Studies of COPD, lung function, emphysema, chronic bronchitis, or mortality in workers exposed to nonorganic dust were retrieved.

Prevalence of small opacities in chest radiographs of nickel sinter plant workers.

Radiographs from 745 nickel sinter plant workers were taken and classified by five readers using the International Labour Office (1980) protocol. Each reader worked independently and the films were randomly mixed with films from a non-dust exposed office population and also with films from subjects known to have silicosis or asbestosis. The prevalence of small irregular opacities was selected as the outcome of interest.

Mass spectrometric studies of the toxaphene components 2-exo,3-endo,5-exo,6-endo,8,8,10,10-octachlorobornane (T2) and 2-exo,3-endo,5-exo,6-endo,8,8,9,10,10-nonachlorobornane (T12).

The electron capture negative ion mass spectra of the title compounds show prominent [M-Cl]- ions, and low-abundance ions formed by further elimination of HCl or Cl2. The electron ionization positive ion mass spectra are complex, but structurally informative fragmentations are observed. In particular, fragmentations involving elimination of C2H2Cl2, and not of C2H4, C2H3Cl, C2HCl3 or C2Cl4, indicate that two chlorines are bound to the C2-C3 and C5-C6 units of a norbornane skeleton.

Increasing importance of Trichophyton tonsurans in childhood tinea in New South Wales. The pattern of childhood tinea in New South Wales, Australia 1979-1988: the emergence of Trichophyton tonsurans as an important pathogen in tinea capitis in white children.

A retrospective study was undertaken of 192 cases of culture proven tinea capitis occurring between 1979 and 1988 in a predominantly white population of children in New South Wales (NSW). The aim of the study was to identify whether Trichophyton tonsurans was increasing in importance in the causation of this condition in Australia as it was in many other parts of the world. The results of our study were compared with those of earlier Australian studies.