Comparative assessment of wet and dry garment cleaning Part 1. Environmental and human health assessment

Water-based cleaning of specialty garments is emerging as a potential alternative to dry cleaning. Perchloroethylene, the solvent used in dry cleaning, poses significant human and ecosystem health concerns. This paper is part 1 of a two part series that analyzes the key environmental, human health, performance, economic, and regulatory factors which influence the future of the garment cleaning industry. This paper inventories the environmental releases and wastes associated with the consumption of perchloroethylene in modern dry cleaning machines which ranges from 2.0 to 5.2 kg per 100 kg of clothing cleaned. In addition, water, electricity, and other inputs for both perchloroethylene-based and water-based garment cleaning are compared using data from previous demonstration projects. Toxicological and epidemiological studies provide evidence for the carcinogenicity of perchloroethylene although this classification is controversial. Cancer risks at low levels of exposure associated with modern dry cleaning equipment and good housekeeping practices are unknown and require further investigation. Regardless of these uncertainties, water-based cleaning is preferable to dry cleaning from a human and environmental health perspective.     

A queen pheromone induces workers to kill sexual larvae in colonies of the red imported fire ant (<Emphasis Type="Italic">Solenopsis invicta</Emphasis>)

We conducted five bioassays to study how queens control the execution of sexual larvae by workers in colonies of the red imported fire ant, Solenopsis invicta. In each assay, subset colonies were made from many large polygyne colonies, and the 20 sexual larvae they contained were monitored over time. Sexual larvae mostly survived in queenless colonies, but were mostly killed in colonies with a single dealated queen, regardless of whether or not the queen was fertilized. The larvae were also killed when fresh corpses of queens were added to queenless colonies. Whereas acetone extracts of queens did not produce a significant increase in killings, extracts in buffered saline induced workers to execute most sexual larvae, indicating successful extraction of an execution pheromone. We identified the probable storage location of the chemical as the poison sac, and found both fresh (1 day) and old (21 day) extracts of poison sacs to be equally effective in inducing executions. The pheromone is stable at room temperature, perhaps because venom alkaloids also present in the extracts keep the pheromone from degrading. It is apparently either proteinaceous or associated with a proteinaceous molecule, a novel finding, as no queen pheromone of a proteinaceous nature has been previously demonstrated in ants.     

Cleft palate: Confirmation of prenatal diagnosis by colour Doppler ultrasound

We present a case of a twin with trisomy 47,XX+i(9p) in whom the diagnosis of cleft palate was confirmed by colour Doppler imaging demonstrating abnormal fluid flow across the fetal pharyngeal bone defect. Application of this technique in cases predisposed for this congenital lesion may prove beneficial in the diagnosis of the more subtle types of isolated cleft palate.     

Immunity in a Social Insect

 Although pathogens appear to have exerted significant selective pressure on various aspects of sociality, mechanisms of disease resistance in the social insects are poorly understood. We report here on an immune response to infection by the dampwood termite, Zootermopsis angusticollis. Nymphs immunized with an injection of 7.6×10⁷, 7.6×10⁵, or 7.6×10⁴ cells/ml glutaraldehyde-killed solution of the bacterium Pseudomonas aeruginosa had significantly higher survivorship than controls following a challenge with a lethal concentration of active bacteria. Similarly, nymphs exposed to a 9×10^–1 spores/ml suspension of the fungus Metarhizium anisopliae had higher survivorship than controls after a challenge with a lethal concentration of spores. Prior exposure to a pathogen thus conferred upon termites a degree of protection during a subsequent encounter with the same pathogen. This represents the first demonstration of immune function in vivo in a social insect. Received: 18 May 1999 / Accepted in revised form: 26 August 1999     

Cytoskeletal elements in the bacterium Mycoplasma pneumoniae

Mycoplasma pneumoniae is a pathogenic eubacterium lacking a cell wall. Three decades ago, a "rod", an intracellular cytoskeletal structure, was discovered that was assumed to define and stabilize the elongated cell shape. Later, by treatment with detergent, a "Triton shell" (i.e. a fraction of detergent-insoluble cell material) could be obtained, believed to contain additional cytoskeletal elements. Now, by application of a modified Triton X-100 treatment, we are able to demonstrate that M. pneumoniae possesses a cytoskeleton consisting of a blade-like rod and a peripheral lining located close to the inner face of the cytoplasmic membrane, exhibiting features of a highly regular network. Attached "stalks" may support the cytoplasmic membrane. The rod was connected to the cell periphery by "spokes" and showed a defined ultrastructure. Its proximal end was found to be attached to a wheel-like complex. Fibrils extended from the proximal end of the rod into the cytoplasm.     

Prenatal diagnosis of a new syndrome: Holoprosencephaly with hypokinesia

Markedly decreased fetal activity (akinesia/hypokinesia) is usually readily apparent to experienced mothers, and frequently this concern leads to attempts at prenatal diagnosis. We report prenatal diagnosis of two fetuses with congenital contractures, markedly decreased fetal movement, and microcephaly due to severe holoprosencephaly. Such familial recurrence to phenotypically normal parents suggests a newly recognized autosomal recessive or X-linked syndrome that is readily detectable by prenatal ultrasonography.     

Familial congenital diaphragmatic hernia: Prenatal diagnosis,management, and outcome

Congenital diaphragmatic hernia (CDH) is a developmental defect of as yet unknown aetiology which accounts for 8 per cent of all major congenital anomalies and is associated with up to 80 per cent mortality despite optimal postnatal treatment. The risk of recurrence of CDH for future sibs after one affected infant is about 2 per cent. A multifactorial/threshold inheritance pattern with an observed high male:female sex ratio is currently favoured for the rare occurrence of familial CDH, although other modes of inheritance have also been described. We report three cases of familial CDH, two of whom were brother and sister sibs and the third was a first cousin, born within 18 months of each other. The diagnosis was by ultrasound and there were several factors predicting a poor outcome. The mortality in this group was 100 per cent. The prenatal diagnosis, treatment options, the unusual genetic aspects, outcome, and the pathology involved are discussed.     

Forest dynamics in Oregon landscapes: evaluation and application of an individual-based model.

The FORCLIM model of forest dynamics was tested against field survey data for its ability to simulate basal area and composition of old forests across broad climatic gradients in western Oregon, USA. The model was also tested for its ability to capture successional trends in ecoregions of the west Cascade Range. It was then applied to simulate present and future (1990-2050) forest landscape dynamics of a watershed in the west Cascades. Various regimes of climate change and harvesting in the watershed were considered in the landscape application. The model was able to capture much of the variation in forest basal area and composition in western Oregon even though temperature and precipitation were the only inputs that were varied among simulated sites. The measured decline in total basal area from tall coastal forests eastward to interior steppe was matched by simulations. Changes in simulated forest dominants also approximated those in the actual data. Simulated abundances of a few minor species did not match actual abundances, however. Subsequent projections of climate change and harvest effects in a west Cascades landscape indicated no change in forest dominance as of 2050. Yet, climate-driven shifts in the distributions of some species were projected. The simulation of both stand-replacing and partial-stand disturbances across western Oregon improved agreement between simulated and actual data. Simulations with fire as an agent of partial disturbance suggested that frequent fires of low severity can alter forest composition and structure as much or more than severe fires at historic frequencies.