Lead: ongoing public and occupational health issues in vulnerable populations: a case study.

BACKGROUND: Lead has been recognized increasingly as a public health risk, although with the introduction of wide-ranging occupational and public health measures, levels of blood lead in the general population of the UK and other developed nations have been in decline in recent years. Nonetheless, cases of lead poisoning still occur. METHODS: We report on a large cluster of exposed lead workers and their families, including several children. The focus of the occupational and public health investigations was to identify the different groups at risk and the pathways by which potential exposures were taking place. RESULTS: Lead in the workplace was found to account for the raised blood lead levels amongst the workers with exposure occurring as a result of insufficient demarcation between 'clean' and 'dirty' areas, and from contamination of personal belongings with lead. Furthermore, there was evidence of para-occupational exposure of family members. CONCLUSIONS: The successful control of lead in this case required multidisciplinary working. Efforts included extensive workplace controls, along with the education and care of workers and their families, though complicated by lack of familiarity with the UK health service amongst the affected groups, language barriers, underlying low levels of literacy and high mobility.

Pheasant rearer's lung.

A 47-year-old gamekeeper presented with an 8 month history of variable breathlessness, cough and clinical features of severe interstitial lung disease. Open lung biopsy showed an extrinsic allergic alveolitis, which we believe related to his work rearing pheasants. Initially he was resistant, despite advice, to changing his occupation but subsequently, although ceasing exposure to pheasants and beginning treatment with corticosteroids, his disease progressed to the point where he developed respiratory failure and was referred for lung transplantation. Sadly, he died of progressive respiratory failure and cor pulmonale complicated by bronchopneumonia before this could be achieved.

Construction of efficient centromeric, multicopy and expression vectors for the yeast Kluyveromyces marxianus using homologous elements and the promoter of a purine-cytosine-like permease.

Efficient centromeric and multicopy vectors have been constructed for the yeast Kluyveromyces marxianus using homologous ARS and centromere sequences. A homologous promoter of a purine-cytosine permease gene called PCPL3 has been cloned, using an expression system based on GUS. Its strength has been estimated in K. marxianus by putting the homologous beta-glucosidase gene under its control. This promoter is very efficient as activities higher than the ones obtained with the Saccharomyces cerevisiae PGK promoter were obtained. This promoter appears to be constitutive in various conditions tested. Its five transcription start sites have been mapped, and a derivative expression vector for K. marxianus has been constructed.

Kinetic model for erythrocyte aggregation.

It is well known that light transmission through blood is the most widely utilized method for the study of erythrocyte aggregation. The curves obtained had been considered empirically as exponential functions. In consequence, the process becomes characterized by an only parameter that varies with all the process factors without discrimination. In the present paper a mathematical model for RBC aggregation process is deduced in accordance with von Smoluchowski's theory about the kinetics of colloidal particles agglomeration. The equation fitted the experimental pattern of the RBC suspension optical transmittance closely and contained two parameters that estimate the most important characteristics of the aggregation process separately, i.e., (1) average size of rouleaux at equilibrium and (2) aggregation rate. The evaluation of the method was assessed by some factors affecting erythrocyte aggregation, such as temperature, plasma dilutions, Dextran 500, Dextran 70 and PVP 360, at different media concentrations, cellular membrane alteration by the alkylating agent TCEA, and decrease of medium osmolarity. Results were interpreted considering the process characteristics estimated by the parameters, and there were also compared with similar studies carried out by other authors with other methods. This analysis allowed us to conclude that the equation proposed is reliable and useful to study erythrocyte aggregation.

Structure of the chromosomal insertion site for pSAM2: functional analysis in Escherichia coli.

The element pSAM2 from Streptomyces ambofaciens integrates into the chromosome through site-specific recombination between the element (attP) and the chromosomal (attB) sites. These regions share an identity segment of 58bp extending from the anti-codon loop through the 3' end of a tRNA(Pro) gene. To facilitate the study of the attB site, the int and xis genes, expressed from an inducible promoter, and attP from pSAM2 were cloned on plasmids in Escherichia coil. Compatible plasmids carrying the different attB regions to be tested were introduced in these E. coli strains. Under these conditions, Int alone could promote site-specific integration; Int and Xis were both required for site-specific excision. This experimental system was used to study the sequences required in attB for efficient site-specific recombination. A 26 bp sequence, centred on the anti-codon loop region and not completely included in the identity segment, retained all the functionality of attB; shorter sequences allowed integration with lower efficiencies. By comparing the 26-bp-long attB with attP, according to the Lambda model, we propose that B and B', C and C' core-type Int binding sites consist of 9 bp imperfect inverted repeats separated by a 5 bp overlap region.

Stabilization of methionine-rich protein in Saccharomyces cerevisiae: targeting of BZN protein into the peroxisome.

We have constructed a gene coding for the 12-kDa intermediate form of the 2s methionine-rich protein from Bertholletia excelsa seeds. This protein, expressed intracellularly in yeast, is characterised by a 20-min half-life. By adding 11 amino acids corresponding to the peroxisome-targeting sequence (PTSc) of luciferase, we have significantly increased its half-life. This stabilization allowed accumulation of the BZN protein into the peroxisome as judged by cell fractionation. Accumulation of the 12-kDa protein results in a significant increase of the total methionine content in yeast cells (30%) indicating that such a microorganism could represent a practicable protected shuttle for an animal-feed additive.

Child health and childminding.

With the objective of determining whether training childminders could improve the health of the children in their care, a controlled trial was conducted among volunteer childminders in a white working-class community in Johannesburg. A small sample of non-volunteer childminders studied did not differ significantly from the minders who did volunteer to participate in the study, except in that they claimed to have more difficulty in attending the training course. The results show that demographic features and scores for the trainee and control groups did not differ significantly before training. After training there were improvements in 4 of the 5 measured scores for the trainee group as opposed to the control group, namely the number of physically detected medical problems, the children's immunisation status, the physical and emotional environment provided by the childminders, and the childminders' knowledge of first aid. The medium-term findings of this study show that training childminders is worthwhile in this community.

The promoter of the beta-glucosidase gene from Kluyveromyces fragilis contains sequences that act as upstream repressing sequences in Saccharomyces cerevisiae.

The relationship between the promoter length of the Kluyveromyces fragilis beta-glucosidase gene and the level of its expression in Saccharomyces cerevisiae was studied by gene fusion between deleted promoter fragments of various lengths and the promoterless beta-galactosidase gene of Escherichia coli. The removal of a region from position -425 to -232 led to a tenfold increase in the expression of the gene. The same results were obtained for the reconstructed beta-glucosidase gene with the same promoter length. It is likely that the deletion of this part of the promoter removes negative regulatory elements which are functional in Saccharomyces cerevisiae. This increase in activity is the main event which may explain the high increase in gene expression (60-fold) previously observed for an upstream deletion obtained during subcloning experiments of the beta-glucosidase gene. It is also shown that the expression of the gene greatly depends upon the nature of the recipient strain, the growth phase of the cell and that of the vector carrying it.

Comparison of the properties of the purified beta-glucosidase from the transformed strain of Saccharomyces cerevisiae TYKF2 with that of the donor strain Kluyveromyces fragilis Y610.

Saccharomyces cerevisiae TYKF2 was obtained by cloning in S. cerevisiae the gene coding for beta-glucosidase in Kluyveromyces fragilis Y610 (ATCC 12424). The beta-glucosidases of both organisms were purified and their biochemical characteristics were determined. The two beta-glucosidases had the same enzymatic properties as those previously described in the literature. The strain S. cerevisiae TYKF2 is able to produce enhanced amounts of enzyme.

Sequence and transcription of the beta-glucosidase gene of Kluyveromyces fragilis cloned in Saccharomyces cerevisiae.

The complete nucleotide sequence of the beta-glucosidase gene of Kluyveromyces fragilis has been determined. This sequence contains an open reading frame of 2535 base pairs encoding a protein of 845 amino acids. Analysis of the transcription products revealed only one transcript of about 3 kb identical in both Kluyveromyces fragilis and in the expression host Saccharomyces cerevisiae. The protein molecular weight of 93,811 Kd deduced from the sequence is consistent with the 90,000 Kd determined by SDS polyacrylamide gel electrophoresis with the purified protein. Mapping of the starts of transcription shows that two starting points are used in the natural host Kluyveromyces fragilis. A comparison of the amino acid sequence with that of other beta-glucosidases revealed three regions of homology. One of these regions contains an amino acid sequence very similar to a peptide isolated from the active site of beta-glucosidase A3 from Aspergillus wentii and could be implicated in the catalytic mechanism of these glucolytic enzymes.

Biosynthesis regulation of the beta-glucosidase produced by a yeast strain transformed by genetic engineering.

The biosynthesis of the beta-glucosidase enzyme was studied in a transformed yeast obtained by cloning in Saccharomyces cerevisiae the structural gene coding for beta-glucosidase in Kluyveromyces fragilis. The enzyme biosynthesis was found to be non-adaptative, and repressed by glucose. These features are similar to those observed in K. fragilis. beta-Glucosidase activity in the transformed yeast was much higher than in K. fragilis. We attempted to ferment cellobiose with the transformed yeast: practically no cellobiose was consumed, growth and ethanol production were negligible. Warburg experiments showed that cellobiose fermentation did not occur when the respiratory chain was not functioning.

Cloning and expression of the structural gene for beta-glucosidase of Kluyveromyces fragilis in Escherichia coli and Saccharomyces cerevisiae.

Cellobiose, the last product in cellulose degradation, is converted into two molecules of glucose by a beta-glucosidase. S. cerevisiae does posses the structural gene for a beta-glucosidase, but it is very poorly expressed; we thus decided to isolate and characterize that of Kluyveromyces fragilis. We constructed in E. coli HB101 strain a genomic library of the Kluyveromyces fragilis Y610 strain (ATCC 12424), a yeast able to grow on cellobiose and which constitutively produces the beta-glucosidase. The structural gene for beta-glucosidase was identified by its expression in E. coli. The initial isolated cosmid KF1 contained an insert of 35 Kb and by successive subcloning the insert size was reduced to 3.5 Kb (KF4). This cloned beta-glucosidase gene introduced in S. cerevisiae by transformation is expressed at a level of about 500 times that of K. fragilis. We checked by Southern hybridization that the high expression level was not due to a rearrangement of K. fragilis DNA during the cloning experiments. Nevertheless to obtain yeast transformants able to grow on cellobiose a yeast strain whose permeability to sugar is increased must be used and this last point is discussed.

A health status and health service utilization study of a peri-urban community in Kwazulu.

A community survey was undertaken in a district in Kwazulu, adjacent to Pietermaritzburg. Natal, in order to determine health status and health service utilization patterns at a local level. This low-cost survey was labour-efficient and yielded useful data for the evaluation and planning of local health services. It was found that child health and delivery services were under-utilized while family planning and antenatal care services were comparatively well used. 'Traditional' practitioners' services were used regularly by 51% of the mothers and childminders interviewed. The use of the services of general medical practitioners was less significant. Some 36% of the children under 5 years of age were found to be malnourished, and 29% had conditions requiring medical treatment. The findings of this study indicate that a major discrepancy exists between the local need for health services and utilization of the available services. The introduction of community health workers is proposed as a possible solution.

[Felty's syndrome. A case report. Review of literature (author's transl)]. / Le syndrome de Felty. A propos d'un cas. Revue de la littérature.

The authors report a case of Felty's syndrome in which are discussed over the data of literature: clinical features, hematological characteristics with a study of neutropenia mechanism and therapeutic possibilities.

Current concepts of rape victim management.

Recommendations for the psychological and medical management of the rape victim are made, as are recommendations on the gathering of medicolegal evidence. The practitioner is a key figure in prevention of secondary victimization. The use of ancillary personnel is recommended.