Polycyclic aromatic hydrocarbons in air samples of meat smokehouses.

In a screening programme nine Danish meat smokehouses were randomly selected for measurements on concentration of airborne polycyclic aromatic hydrocarbons (PAH). A total of 23 stationary air samples were collected during the entire working period of the kiln either above the kiln doors or approximately 2 m in front of the kiln doors (i.e. total exposure on the day of sampling). Three of these samples had a PAH content below the detection limit of the highly sensitive assay employed. Furthermore, eight personal air samples were collected during the periods of tending the kiln (i.e. peak exposure measurement). Three of these samples were below the detection limit. Total airborne PAH concentration of the stationary air samples calculated as the sum of the concentration of 16 selected PAH compounds, was in general far lower than the total airborne PAH concentration measured in the same manner in smokehouses curing fish (Nordholm et al., 1986). In contrast to the study on PAH exposure in smokehouses curing fish, the present study revealed no significant difference between total PAH content in air samples collected above the kilns compared with samples collected approximately 2 m in front of the kiln doors. Calculation of the relative content of the individual PAH compounds in the stationary air samples collected in meat smokehouses showed naphthalene to be the major compound in (70% +/- 26% of total PAH), whereas the relative content of carcinogenic PAH compounds in average represented 4.0% of the total PAH content. However, only approximately 15% of the stationary air samples with detectable content of total PAH contained detectable amounts of carcinogenic PAH compounds. Hence it was concluded that PAH exposure during cold meat curing might be considered a limited health hazard compared with PAH exposure during hot fish curing.     

Using Linked Micromap Plots to Characterize Omernik Ecoregions

The paper introduces linked micromap (LM) plots for presenting environmental summaries. The LM template includes parallel sequences of micromap, label, and statistical summary graphics panels with attention paid to perceptual grouping, sorting and linking of the summary components. The applications show LM plots for Omernik Level II Ecoregions. The summarized United States continental data includes USGS digital elevation, 30-year normal precipitation and temperature, and 8 million AVHRR pixels classified into 159 types of land cover. One LM plot uses a line-height glyph to represent all 159 land cover percentages per ecoregion. LM plots represent new visualization methodology that is useful in the data and knowledge based pattern representation and knowledge discovery process. The LM plots focus on providing an orienting overview. The overview provides a starting place for subsequent drilling down to what could otherwise be viewed as an overwhelming mass of data. The overview also provides a starting place to learn about the intellectual structure that lies behind the notion of ecoregions and begins to connect this abstract structure to quantitative methods.     

Declining sperm counts in the United States? A critical review

PURPOSE: Recent reports suggest declining sperm counts in the United States. These reports did not include all available data and did not account for geographic variations noted in prior studies. We examined all available data on U.S. sperm counts and evaluated whether geographic variations account for the decline suggested. MATERIALS AND METHODS: We reviewed all 29 U.S. studies from 1938 to 1996 reporting manually counted semen analyses of 9,612 fertile or presumably fertile men. We determined mean sperm concentrations by geographic location with weighted analysis of variance, and assessed any changes with time by linear regression analysis. RESULTS: Mean sperm concentrations from New York were significantly higher than from all other U.S. cities (98.6 versus 71.6 x 10(6) sperm per cc, respectively, p = 0.006). There has been no statistically significant change with time for mean sperm concentrations reported from New York (p = 0.49) or from U.S. cities other than New York (p = 0.62). Analysis without separating by location revealed a decline (p = 0.047). CONCLUSIONS: Sperm concentrations are highest in New York compared to other U.S. cities. When accounting for this geographic difference and examining all available data, there appears to be no significant change in sperm counts in the U.S. during the last 60 years. Further studies addressing the causes of geographic variations are needed.     

Apoptosis in batch cultures of Chinese hamster ovary cells

One of the main problems in the culture of Chinese Hamster Ovary (CHO) cells continues to be the inability to maintain the viability of the cultures over an extended period of time. The rapid decline in viability at the end of the culture is exacerbated by the absence of serum. In trying to reduce the extent of death in these cultures, we first tried to determine the mode of death. We found that more than 80% of the cells in a standard serum-free batch culture of CHO cells in suspension died via apoptosis--as evidenced by condensed chromatin and the appearance of a characteristic DNA ladder. Furthermore, when protein synthesis was inhibited using cycloheximide, the cells underwent rapid apoptosis indicating that death proteins were present in greater abundance than survival proteins in our CHO cells. Cell lysate from CHO cells showed evidence of cysteine protease (caspase) activity. Caspases of the Interleukin-1-beta-Converting Enzyme (ICE) family, e.g., CPP32, Mch-1, etc., have been implicated in the apoptotic process. Surprisingly, a caspase peptide inhibitor, N-benzyloxycarbonyl-Val-Ala-Asp-fluoro-methyl-ketone (z-VAD.fmk), was unable to substantially extend the life of a serum-free batch culture of CHO cells. In addition, z-VAD.fmk was only marginally able to extend viability in response to withdrawal of growth and survival factors, insulin and transferrin. In both these instances, z-VAD.fmk was able to prevent cleavage of caspase substrates, but not protect cells from death. However, we found that bcl-2 expression was able to significantly extend viabilities in CHO batch culture. Bcl-2 expression also substantially extended the viability of cultures in response to insulin and transferrin withdrawal. These results provide interesting insights into the pathways of death in a CHO cell.     

Clinicopathologic features of dogs with hepatic microvascular dysplasia with and without portosystemic shunts: 42 cases (1991-1996)

A 14 year old girl with double outlet right ventricle, left isomerism, and complicated atrial anatomy had undergone corrective surgery with intra-atrial rerouting at 5 years of age. Cardiac catheterisation eight years after the surgery showed that she had two systemic venous baffle stenoses: between the hepatic vein and caval vein, and the caval vein and right atrium. Two Palmaz stents were successfully implanted percutaneously through a long sheath and a balloon catheter. The stenoses were relieved immediately and her symptoms quickly disappeared.     

Strength and conflicting valence in the measurement of food attitudes and preferences

There is a trend in current attitude research to move away from a simple uni-dimensional view of attitude, towards examining a more multivariate concept of attitude. An extensive array of attitudinal properties or dimensions has been provided, defined and categorised as ‘attitude strength’. Attitude strength has only recently been adapted as a conceptual framework for research in marketing and consumer studies. Our objective in this paper is to introduce some of the attitude strength concepts and literature in order to improve the measure and understanding of research dealing with measurement of food preferences, perceived food quality and satisfaction with food products, food suppliers, etc. The paper takes a particular focus upon problems in comprehending the middlemost choice or neutrality when measuring attitude items along a traditional bipolar semantic differential or a bipolar hedonic preference scale. Through several propositions, we have outlined how future research should note that both attitude ambivalence (mixed feelings) and non-attitude (lack of confidence in evaluation) could be threats to comprehending the middlemost response alternative on a questionnaire as neutral when measuring food attitudes or preferences in the traditional way. Our approach should also deal with some of the shortcomings of analysing attitude–behaviour consistency when modelling food consumption behaviour.     

Toward wide-scale all-optical transparent networking: the ACTSoptical pan-European network (OPEN) project

The European ACTS project optical pan-European network (OPEN) aims at assessing the feasibility of an optical pan-European overlay network, interconnecting major European cities by means of a mesh of high-capacity optical fiber links, cross-connected through transparent photonic nodes. Both the transmission links and the routing network elements rely on wavelength division multiplexing (WDM) all-optical technologies, such as wavelength translation. This paper presents results obtained in the following domains covered within the project: network topology considerations (optimization and dimensioning); network physical layer simulation; fabrications of packaged functional modules based on advanced optoelectronic devices; laboratory demonstrations of N×10 Gb/s transmission and routing; feasibility of an optical time division multiplexing/WDM (OTDM/WDM) interface; and the field implementation of a 4×4 multiwavelength crossconnect prototype, featuring all-optical space and wavelength routing. This implementation was realized in two cross-border field trials, one conducted between Norway and Denmark and the other between France and Belgium. The final results of the Norway to Denmark field trials are presented, featuring the successful cascade of three wavelength-translating optical crossconnects (OXCs), along with the transmission over 1000 km of a mix of standard/submarine cable links for four channels at 2.5 Gb/s     

Age- and sex-related differences in nuclear lipid content and nucleoside triphosphatase activity in the JCR:LA-cp corpulent rat

The putative role of the nuclear nucleoside triphosphatase (NTPase) is to provide energy to the nuclear pore complex for poly A(+) mRNA export. Previous work has demonstrated that liver nuclear NTPase activity is greater in 6 month old corpulent (cp/cp) female JCR:LA rats, a hyperlipidemic rat model, compared to lean (+/?) animals. This increase appeared to be related to increases in nuclear membrane cholesterol content. The current study extended these initial data to compare NTPase activity as a function of age and sex in isolated JCR:LA-cp rat liver nuclei, to further test the hypothesis that nuclear membrane cholesterol may modulate NTPase activity. NTPase activity was increased in cp/cp female animals compared to +/? females at all ages studied, with Vmax values increased by 60-176%. Membrane integrity of cp/cp female nuclei was reduced compared to +/? female nuclei. Nuclear membrane cholesterol levels increased linearly with age by 50, 150 and 250% in 3, 6 and 9 month old cp/cp females over leans. In contrast, nuclei from cp/cp males exhibited only minor, isolated changes in NTPase activity. Furthermore, there were no significant changes in nuclear cholesterol content or membrane integrity in the less hyperlipidemic male animals at any age. These data suggest that altered lipid metabolism may lead to changes in nuclear membrane structure, which in turn may alter NTPase activity and functioning of the nuclear pore complex.     

Characterization of the copper chaperone Cox17 of Saccharomyces cerevisiae

Assembly of functional cytochrome oxidase in yeast requires Cox17, which has been postulated to deliver copper ions to the mitochondrion for insertion into the enzyme. This role for Cox17 is supported by the observation that it binds copper as a binuclear cuprous-thiolate cluster. X-ray absorption spectroscopy, together with UV-visible absorption and emission spectroscopy, indicates the presence of bound cuprous ions, trigonally coordinated by thiolate ligands. Analysis of the EXAFS shows three Cu-S bonds at 2.26 A, plus a short Cu-Cu distance of 2.7 A, indicating a binuclear cluster in Cox17. The cuprous-thiolate cluster in Cox17 is substantially more labile than structurally related clusters in metallothioneins.