Bioaccumulation of pollutants and changes in population parameters in the gastropod mollusc Austrocochlea constricta

The gastropod mollusc Austrocochlea constricta was collected from four marine locations within the Newcastle region of New South Wales, Australia to assess the range and distribution of major bioaccumulated organic and heavy metal pollutants. The metals and organopollutants were extracted from the soft tissue and the shell of the mollusc for analysis using atomic absorption spectroscopy (AAS) and gas chromatography-mass spectroscopy (GC-MS). The organisms accumulated heavy metals from the sea water and concentrated them to levels substantially higher than those in the surrounding environment. A wide range of organopollutants was also detected in varying levels in Austrochochlea from each location. Abietic and dehydroabietic acids were detected only in the shell and not in the soft tissue suggesting that the shell may act as a toxic waste sink to facilitate the removal of potentially harmful compounds from the more metabolically active soft tissue. Aliphatic hydrocarbon contaminants were detected in Austrocochlea derived from the three sites associated with either heavy industry or recreational boating, but no hydrocarbons were detected in organisms from the control site. It was concluded that Austrocochlea may serve as a useful biomonitoring system of pollutants bioaccumulated from marine environments.     

Characterization of the epitope recognized by a mAb that reacts differentially with murine suppressor T cells

Although reliable antibodies are available that distinguishhuman suppressor T (T_s) cells from CTL and other T cells, feware available for murine T_s cells. We have developed a mAb (984D4.6.5)that, in the presence of complement, depletes alloantigen-specificT_s cells but not CTL. This antibody recognizes activated TT_scells but not their precursors. In these studies, flow cytometricanalysis demonstrates that 984D4.6.5 reacts with several T_scell hybridomas, cloned T_h cell lines and WEHI-3 (a myelomonocytictumor cell line). Reactivity was not detected with BW5147, T_hcell hybridomas, cloned T_h cells, CTL lines and hybridomas,B cell lines, thymocytes, splenocytes, bone marrow cells nora variety of tumor cells. Among 984D4.6.5 positive lines, expressionis heterogeneous and the number of cells expressing high levelsof the epitope is increased when the hybridomas are maintainedat a relatively high cell density. Neuriminidase and pronasedeplete the epitope recognized by mAb 984D4.6.5. Protein synthesisand glycosylation inhibitors also reduce expression of thisepitope. These observations suggest that the epitope recognizedby 984D4.6.5 is a carbohydrate linked to a polypeptide. Thisantibody was tested by ELISA for binding to a large panel ofcarbohydrates and glycollpids coupled to BSA. The only one thatbound 984D4.6.5 was LS tetrasaccharide c (NeuNAc2-6Galpß1-4GIcNAcß1-3GaIß1-4Glc),an O-linked carbohydrate. Comparative analysis shows that boththe sequence and the linkage of these sugars are essential tothe reactivity with the 984D4.6.5 antibody. This epitope isexpressed by a glycoprotein of-200 kDa, as shown by Westernblots. The identity of this glycoprotein remains to be determined,but indirect evidence suggests that it is not CD45.     

Contaminant levels in harbor seals from the northeastern United States

The concentrations of polychlorinated biphenyls (PCBs), organochlorine pesticides, polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzofurans (PCDF), polychlorinated dibenzo-p-dioxins (PCDD), and mercury (Hg) were determined in blubber and liver tissues of harbor seals (Phoca vitulina) collected along the northeast coast of the U.S. Average PCB concentrations in seal blubber (sum of congeners) were 12.0 g/g (wet weight) with a range of 7.30 to 24.3 g/g in 1980 and 6.66 g/g (wet weight) with a range of 2.61 to 11.3 g/g in 1990–1992. Comparisons between blubber data from this study and previous work indicated that the concentration of PCBs along the northeast coast of the U.S. may have decreased over the past twenty years.The average p,p-DDE concentrations in seal blubber were 10.9 g/g (wet weight) in 1980 with a range of 6.95 to 21.9 g/g and 4.12 g/g (wet weight) with a range of 1.83 to 7.84 g/g in 1990–1992. Only trace amounts of PCDFs and PCDDs were found in a few blubber samples; levels in most tissues were below detection (3–5 pg/g) (wet weight). Trace amounts (<30 ng/g) of phenanthracene, anthracene, and alkylated MW-178 compounds were found in some seal samples; all other PAH compounds were below the detection level (5–15 ng/g).Toxic equivalents (TEQ) of selected coplanar and mono-ortho PCB congeners and relative toxic equivalents (RTE) (pg total TEQ/g total PCB) were calculated, using recently proposed dioxin toxic equivalent factors (Ahlborg et al. 1994). The TEQs ranged from 41 to 315, and the RTEs ranged from 2.25 to 16.3. The RTEs for seal blubber indicated that the present values were in the midrange of those reported in the literature. Toxic equivalents calculated on the basis of the concentrations of the coplanar PCBs, PCDDs, and PCDFs indicated that coplanar PCBs, rather than PCDDs and PCDFs, may pose a more important toxic threat to harbor seals.Mercury levels in liver tissue averaged 70.0 g/g (wet weight) and 44.1 g/g (wet weight) in the 1991 and 1980 samples, respectively, and are similar to those found in relatively polluted waters of the British Isles.     

Zambia: the role of aid management in sustaining visionary reform

As part of its ongoing reform of the health sector, Zambia has developed a number of systems and structures to coordinate and manage external resources. With increasing attention being given to the potential for sector-wide approaches (SWAps) to enhance the efficiency and effectiveness of health systems in low-income countries, Zambia provides an interesting case study of how this is emerging in practice over time. The paper outlines the different coordination mechanisms and assesses them in terms of selected criteria of effectiveness, finding that the potential to meet reform objectives is currently not being met. Factors influencing the effectiveness of these mechanisms are identified as falling into categories around personalities and human interaction, the nature of reform processes, and the impact of broader context. The need to maintain dialogue in the face of external constraints and uncertainties is stressed.     

Analysis of creams

The possibilities of the gas-liquid chromatographic analysis with flame ionization detection of creams of the o/w emulsion type were investigated. Interferences by cream base components in the determination of the active compounds were studied. It appeared to be possible to determine active compounds with a retention index lower than 1900 onov-17 (e.g. methyl salicylate, menthol, thymol, camphor) without clean-up of the cream samples; for the determination of compounds with retention indices between 1900 and 3700, a simple clean-up step suffices. The possible analysis of some of the cream base components together with the active compounds of the creams was investigated as well. Cetomacrogol emulsifying wax, lanette wax sx and cetiol v could be determined easily, whether or not a sample clean-up step was incorporated.     

The influence of reported paternal attitudes on the decision to breast-feed

Objective: To identify factors that influence a woman's decision to breast-feed.
Methodology: Five hundred and fifty-six women were recruited from the maternity wards of two Perth hospitals. Data were collected from a self-administered questionnaire completed by participants prior to discharge. Logistic regression analysis was used to determine factors influencing the initiation of breast-feeding.
Results: At discharge from hospital 83.8% of women were breast-feeding, including 6% who were giving complementary formula feeds. After controlling for potentially confounding demographic and biomedical factors, the father's reported preference for breast-feeding was found to be the most important factor influencing a woman's decision to breast-feed (OR 10.18).
Conclusion: Fathers participate in and influence the choice of infant feeding method and should be included in breast-feeding discussions.     

Margin of safety for discharge after apnea in preterm infants

OBJECTIVE: Most neonatologists include an apnea-free period in the criteria for the discharge of preterm infants. However, the length of time one should wait after the cessation of apnea before sending an infant home without a monitor is debated. We undertook this study in an attempt to define a minimal and safe observation period between the time of the last apnea episode and discharge. METHODS: We reasoned that in infants with idiopathic apnea of prematurity, the intervals between days on which apnea occurs gradually increase until some point at which clinically significant apnea ceases. Therefore, knowledge about the intervals between days on which apnea occurred just before the last apnea would provide a reasonable estimate of the minimal safe observation interval between the last apnea and discharge. We reviewed the charts of 266 infants born in 1993 and 1994 at 相似文献