Dismal prognosis of Pneumocystis jirovecii pneumonia in patients with multiple myeloma

Patients with multiple myeloma (MM) are at high risk for infections, including opportunistic infections such as Pneumocystis jirovecii pneumonia (PJP). We conducted a retrospective analysis of patients with MM developing PJP over a 6-year period between January 2016 and December 2021 at the University Hospital of Würzburg by screening cases of microbiologically documented PJP. A total of 201 positive results for P. jirovecii in respiratory specimens were retrospectively retrieved through our microbiology database. Of these cases, 13 patients with MM fulfilled the definition of probable PJP according to EORTC fungal disease definitions. We observed two peaks in PJP incidence, one after stem cell transplantation during first-line treatment (n = 5) and the other in heavily pretreated patients with six or more prior lines of therapy (n = 6). There was high morbidity with nine (69%) patients admitted to the ICU, seven of whom (78%) required mechanical ventilation, and high mortality (62%, n = 8). Notably, only two of the 13 patients (15%) had received PJP prophylaxis. The main reason for discontinuation of prophylaxis with trimethoprim-sulfamethoxazole was grade IV neutropenia. The observed morbidity and mortality of PJP in MM patients are significant and even higher than reported for patients with other hematologic malignancies. According to most current guidelines, the use of prophylaxis would have been clearly recommended in no more than three (23%) of the 13 patients. This illustrates the need to critically reconsider the indications for PJP prophylaxis, which remain incompletely defined.

A Photopatternable Conjugated Polymer with Thermal-Annealing-Promoted Interchain Stacking for Highly Stable Anti-Counterfeiting Materials

Photoresponsive polymers can be conveniently used to fabricate anti-counterfeiting materials through photopatterning. However, an unsolved problem is that ambient light and heat can damage anti-counterfeiting patterns on photoresponsive polymers. Herein, photo- and thermostable anti-counterfeiting materials are developed by photopatterning and thermal annealing of a photoresponsive conjugated polymer (MC-Azo). MC-Azo contains alternating azobenzene and fluorene units in the polymer backbone. To prepare an anti-counterfeiting material, an MC-Azo film is irradiated with polarized blue light through a photomask, and then thermally annealed under the pressure of a photonic stamp. This strategy generates a highly secure anti-counterfeiting material with dual patterns, which is stable to sunlight and heat over 200 °C. A key for the stability is that thermal annealing promotes interchain stacking, which converts photoresponsive MC-Azo to a photostable material. Another key for the stability is that the conjugated structure endows MC-Azo with desirable thermal properties. This study shows that the design of photopatternable conjugated polymers with thermal-annealing-promoted interchain stacking provides a new strategy for the development of highly stable and secure anti-counterfeiting materials.

Hydrological controls on base metal precipitation and zoning at the porphyry-epithermal transition constrained by numerical modeling

Ore precipitation in porphyry copper systems is generally characterized by metal zoning (Cu-Mo to Zn-Pb-Ag), which is suggested to be variably related to solubility decreases during fluid cooling, fluid-rock interactions, partitioning during fluid phase separation and mixing with external fluids. Here, we present new advances of a numerical process model by considering published constraints on the temperature- and salinity-dependent solubility of Cu, Pb and Zn in the ore fluid. We quantitatively investigate the roles of vapor-brine separation, halite saturation, initial metal contents, fluid mixing and remobilization as first-order controls of the physical hydrology on ore formation. The results show that the magmatic vapor and brine phases ascend with different residence times but as miscible fluid mixtures, with salinity increases generating metal-undersaturated bulk fluids. The release rates of magmatic fluids affect the location of the thermohaline fronts, leading to contrasting mechanisms for ore precipitation: higher rates result in halite saturation without significant metal zoning, lower rates produce zoned ore shells due to mixing with meteoric water. Varying metal contents can affect the order of the final metal precipitation sequence. Redissolution of precipitated metals results in zoned ore shell patterns in more peripheral locations and also decouples halite saturation from ore precipitation.

A streamlined method for the fast and cost-effective detection of bacterial pathogens from positive blood cultures for the BacT/ALERT blood culture system using the Vitek MS mass spectrometer

Background and objective

Prompt pathogen identification of blood stream infections is essential to provide appropriate antibiotic treatment. Therefore, the objective of this prospective single centre study was to establish an inexpensive, fast and accurate protocol for bacterial species identification with SDS protein-extraction directly from BacT/Alert^® blood culture (BC) bottles by VitekMS^®.

Results

Correct species identification was obtained for 198/266 (74.4%, 95%-CI = [68.8%, 79.6%]) of pathogens. The protocol was more successful in identifying 87/96 (91.4%, 95%-CI = [83.8%, 93.2%]) gram-negative bacteria than 110/167 (65.9%, 95%-CI = [58.1%, 73.0%]) gram-positive bacteria. The hands-on time for sample preparation and measurement was about 15 min for up to five samples. This is shorter than for most other protocols using a similar lysis-centrifugation approach for the combination of BacT/Alert^® BC bottles and the Vitek^® MS mass spectrometer. The estimated costs per sample were approx. 1.80€ which is much cheaper than for commercial kits.

Conclusion

This optimized protocol allows for accurate identification of bacteria directly from blood culture bottles for laboratories equipped with BacT/Alert^® blood culture bottles and VitekMS^® mass spectrometer.

Photoresponsive metallopolymer nanoparticles for cancer theranostics

Over the past decades, transition metal complexes have been successfully used in anticancer phototherapies. They have shown promising properties in many different areas including photo-induced ligand exchange or release, rich excited state behavior, and versatile biochemical properties. When encorporated into polymeric frameworks and become part of nanostructures, photoresponsive metallopolymer nanoparticles (MPNs) show enhanced water solubility, extended blood circulation and increased tumor-specific accumulation, which greatly improves the tumor therapeutic effects compared to low-molecule-weight metal complexes. In this review, we aim to present the recent development of photoresponsive MPNs as therapeutic nanomedicines. This review will summarize four major areas separately, namely platinum-containing polymers, zinc-containing polymers, iridium-containing polymers and ruthenium-containing polymers. Representative MPNs of each type are discussed in terms of their design strategies, fabrication methods, and working mechanisms. Current challenges and future perspectives in this field are also highlighted.

T-Cell Immune Surveillance in Allogenic Stem Cell Transplant Recipients: Are Whole Blood-Based Assays Ready to Challenge ELISPOT?

We compared the feasibility of 4 cytomegalovirus (CMV)- and Aspergillus-reactive T-cell immunoassay protocols in allogenic stem cell transplant recipients. While enzyme-linked immunospot performed best overall, logistically advantageous whole blood–based assays performed comparably in patients with less severe lymphocytopenia. CMV-induced interferon-gamma responses correlated strongly across all protocols and showed high concordance with serology.

Development and evaluation of a whole blood-based approach for flow cytometric quantification of CD154+ mould-reactive T cells

CD154+ mould-reactive T cells were proposed as a novel biomarker in the diagnosis of invasive mycoses. As PBMC-based protocols for flow cytometric quantification of these cells are logistically challenging and susceptible to preanalytic delays, this study evaluated and optimized a whole blood-based method for the detection of mould-reactive T cells. Blood collection tubes containing costimulatory antibodies and Aspergillus fumigatus mycelial lysates were inoculated with heparinized whole blood from healthy adults, and detection rates of CD154+/CD4+A. fumigatus reactive T cells were compared with PBMC-based detection using samples from the same donors. In contrast to the PBMC-based method, double costimulation with αCD28 and αCD49d was crucial for reliable whole blood stimulation. Optimizing stimulation schemes for both matrixes, significantly higher specific T-cell detection rates were achieved by the whole blood-based method, whereas the unspecific background stimulation remained low. MHC II-dependent CD154+ upregulation was demonstrated for both matrixes. Excellent correlation and reproducible conversion factors between whole blood and PBMC-based results were observed. Using frozen ready-to-use test tubes containing costimulatory antibodies and lysates, detection rates of specific T cells were comparable to freshly prepared blood collection tubes. The optimized whole blood-based protocol was also used to detect Rhizopus arrhizus and Rhizomucor pusillus reactive T cells, resulting in 1.5- to 2.7-fold higher detection rates compared with PBMC-based measurement. In summary, the whole blood protocol is a robust, highly sensitive, and cost-effective method for mould-reactive T-cell quantification, allowing for point-of-care sample stimulation and contributing to better assay standardization in multi-centre evaluation of mould reactive T-cell quantification.

Evaluation of Aspergillus and Mucorales specific T-cells and peripheral blood mononuclear cell cytokine signatures as biomarkers of environmental mold exposure

Mold specific T-cells have been described as a supportive biomarker to monitor invasive mycoses and mold exposure. This study comparatively evaluated frequencies and cytokine profiles of Aspergillus fumigatus and Mucorales reactive T-cells depending on environmental mold exposure. Peripheral blood mononuclear cells (PBMCs) obtained from 35 healthy donors were stimulated with mycelial lysates of A. fumigatus and three human pathogenic Mucorales species. CD154⁺ specific T-cells were quantified by flow cytometry. In a second cohort of 20 additional donors, flow cytometry was complemented by 13-plex cytokine assays. Mold exposure of the subjects was determined using a previously established questionnaire. Highly exposed subjects exhibited significantly greater CD154⁺A. fumigatus and Mucorales specific naïve and memory T-helper cell frequencies. Significant correlation (r = 0.48 - 0.79) was found between A. fumigatus and Mucorales specific T-cell numbers. Logistic regression analyses revealed that combined analysis of mold specific T-cell frequencies and selected cytokine markers (A. fumigatus: IL-5 and TNF-α, R. arrhizus: IL-17A and IL-13) significantly improves classification performance, resulting in 75-90 % predictive power using 10-fold cross-validation. In conclusion, mold specific T-cell frequencies and their cytokine signatures offer promising potential in the assessment of environmental mold exposure. The cytokines identified in this pilot study should be validated in the clinical setting, e. g. in patients with hypersensitivity pneumonitis.

Susceptibility of A. fumigatus-specific T-cell assays to pre-analytic blood storage and PBMC cryopreservation greatly depends on readout platform and analytes

Mould-specific T cells detectable by flow cytometry or ELISPOT were proposed as a novel biomarker in invasive aspergillosis. To define protocols facilitating sample shipment and longitudinal analysis, this study evaluated the susceptibility of different functional assays for A. fumigatus-specific T-cell quantification and characterisation to pre-analytic delays. PBMCs from 6 healthy donors were analysed after immediate isolation, after 6 hours whole blood storage or after cryopreservation using 3 different common media. Functional responses to A. fumigatus lysate stimulation were comparatively assessed by flow cytometry, ELISPOT and 14-plex cytokine assay. After 6 hours pre-analytic storage, all functional assays showed reduced detection rates, higher coefficients of variation (CV) and widely varying individual recovery indices of specific T-cell response. While cryopreservation resulted in sufficient yields and largely unaltered cellular composition, outcomes of functional readouts significantly differed from freshly processed samples. For CD154-based flow cytometry, only cryopreservation in RPMI supplemented with autologous serum resulted in satisfactory detection rates and CVs. For ELISPOT and cytokine secretion assays, none of the cryopreservation protocols provided sufficient concordance with immediately processed samples. Even using the same readout platform, individual analytes widely varied in their susceptibility to cryopreservation, highlighting that distinct optimisation is required depending on the downstream assay.

Multiple Segmental Processes in Polymers with cis and trans Stereoregular Configurations

Altering the stereochemistry of a single double bond in the side group of a polymer resulted in systems with unprecedented local dynamics. These include (i) the appearance of three segmental processes in the cis-polymers all with Vogel-Fulcher-Tammann (VFT) temperature dependence, (ii) the low steepness index associated with fragility, m, and (iii) the lowest pressure coefficient of T_g, dT_g/dP, ever reported for polymers. We show that it is the inability of the cis-polymer to pack the side groups efficiently that controls the dynamics. Furthermore, the trans-polymers have the ability to crystallize. The wealth of dynamics reflects the cis/trans stereochemistry and the presence of different dipoles at specific positions sampling both the side group and backbone dynamics.

Intra- and inter-individual variability of Aspergillus fumigatus reactive T-cell frequencies in healthy volunteers in dependency of mould exposure in residential and working environment

Invasive aspergillosis remains a deadly disease in immunocompromised patients, whereas the combination of an exaggerated immune response and continuous exposure lead to various hyperinflammatory diseases. This pilot study aimed to gain an overview of the intra- and inter-individual variability in Aspergillus fumigatus reactive T-helper cells in healthy adults and the correlation with environmental mould exposure. In this flow cytometric study, the frequencies of CD154⁺ A. fumigatus reactive T cells were evaluated in 70 healthy volunteers. All subjects completed a standardised questionnaire addressing their mould exposure. Subjects with intensive mould exposure in their professional or residential surrounding demonstrated considerably higher mean frequencies of A. fumigatus reactive T-helper and T-memory cells. Comparative evaluation of multiple measurements over time demonstrated relatively conserved reactive T-cell frequencies in the absence of major changes to the exposure profile, whereas those frequently exposed in professional environment or with changes to their risk score demonstrated a marked dependency of antigen reactive T-cell frequencies on recent mould exposure. This pilot study was the first to provide data on the intra-individual variability in A. fumigatus reactive T-cell frequencies and its linkage to mould encounter. Fungus reactive T cells are to be considered a valued tool for the assessment of environmental mould exposure.

Mucorales spores induce a proinflammatory cytokine response in human mononuclear phagocytes and harbor no rodlet hydrophobins

Mucormycoses are life-threatening infections in immunocompromised patients. This study characterizes the response of human mononuclear cells to different Mucorales and Ascomycota. PBMC, monocytes, and monocyte derived dendritic cells (moDCs) from healthy donors were stimulated with resting and germinated stages of Mucorales and Ascomycota. Cytokine response and expression of activation markers were studied. Both inactivated germ tubes and resting spores of Rhizopus arrhizus and other human pathogenic Mucorales species significantly stimulated mRNA synthesis and secretion of proinflammatory cytokines. Moreover, R. arrhizus spores induced the upregulation of co-stimulatory molecules on moDCs and a specific T-helper cell response. Removal of rodlet hydrophobins by hydrofluoric acid treatment of A. fumigatus conidia resulted in enhanced immunogenicity, whereas the cytokine response of PBMCs to dormant R. arrhizus spores was not influenced by hydrofluoric acid. Scanning electron micrographs of Mucorales spores did not exhibit any morphological correlates of rodlet hydrophobins. Taken together, this study revealed striking differences in the response of human mononuclear cells to resting stages of Ascomycota and Mucorales, which may be explained by absence of an immunoprotective hydrophobin layer in Mucorales spores.

Light-Switchable Azobenzene-Containing Macromolecules: From UV to Near Infrared

Azobenzene-containing macromolecules (azo-macromolecules) such as azobenzene-containing polymers (azopolymers) and azobenzene-functionalized biomacromolecules are photoswitchable macromolecules. Trans-to-cis photoisomerization in conventional azo-macromolecules is induced by ultraviolet (UV) light. However, UV light cannot penetrate deeply into issue and has a very small fraction in sunlight. Therefore, conventional azo-macromolecules are problematic for biomedical and solar-energy-related applications. In this Feature Article, the strategies for constructing visible and near-infrared (NIR) light-responsive azo-macromolecules are reviewed, and the potential applications of visible- and NIR-light-responsive azo-macromolecules in biomedicine and solar energy conversion are highlighted. The remaining challenges in the field of photoswitchable azo-macromolecules are discussed.

Quantification of A. fumigatus-specific CD154+ T-cells-preanalytic considerations

Fungal specific CD154⁺ T-cells have been described as a biomarker in invasive aspergillosis. The influence of sample storage on the detection of these cells was assessed. Six-hour delay prior to PBMC isolation is associated with an 18% decrease of cell viability and alterations of the cellular composition of the sample. This results in 87% reduction of CD154⁺ A. fumigatus specific cells due to reduced assay sensitivity and increased background values in unstimulated samples. If prompt cell measurement is not feasible, isolated PBMCs can be frozen (at -20°C and -80°C) and processed later with comparable assay reliability (mean value fresh vs. thawing: 0.126, 0.133; Pearson-Coefficient: 0.962).

Geologic controls on supercritical geothermal resources above magmatic intrusions

A new and economically attractive type of geothermal resource was recently discovered in the Krafla volcanic system, Iceland, consisting of supercritical water at 450 °C immediately above a 2-km deep magma body. Although utilizing such supercritical resources could multiply power production from geothermal wells, the abundance, location and size of similar resources are undefined. Here we present the first numerical simulations of supercritical geothermal resource formation, showing that they are an integral part of magma-driven geothermal systems. Potentially exploitable resources form in rocks with a brittle–ductile transition temperature higher than 450 °C, such as basalt. Water temperatures and enthalpies can exceed 400 °C and 3 MJ kg⁻¹, depending on host rock permeability. Conventional high-enthalpy resources result from mixing of ascending supercritical and cooler surrounding water. Our models reproduce the measured thermal conditions of the resource discovered at Krafla. Similar resources may be widespread below conventional high-enthalpy geothermal systems.

Utilizing supercritical geothermal water could multiply energy production, but the abundance, location and size of such resources is unclear. Here, the authors present numerical simulations and suggest that supercritical water may play a key role in removing heat from all magmatic intrusions.

Towards loss compensated and lasing terahertz metamaterials based on optically pumped graphene

We evidence by numerical calculations that optically pumped graphene is suitable for compensating inherent loss in terahertz (THz) metamaterials. We calculate the complex conductivity of graphene under optical pumping and determine the proper conditions for terahertz amplification in single layer graphene. It is shown that amplification in graphene occurs up to room temperature for moderate pump intensities at telecommunication wavelength λ = 1.5 μm. Furthermore, we investigate the coupling between a plasmonic split ring resonator (SRR) metamaterial and optically pumped graphene at a temperature T = 77 K and a pump intensity I = 300 mW/mm(2). We find that the loss of a SRR metamaterial can be compensated by optically stimulated amplification in graphene. Moreover, we show that a hybrid material consisting of asymmetric split-ring resonators and optically pumped graphene can emit coherent THz radiation at minimum output power levels of 60 nW/mm(2).

[Correlation of patients age on length of stay and admission rate in a German emergency department]

BACKGROUND

This study aimed to examine correlations between patient age, length-of-stay (LOS) in the emergency department (ED), admission rate for various medical disciplines and probabilities of admission in a German interdisciplinary ED.

PATIENTS AND METHODS

In a retrospective cohort analysis, 7937 patients of the ED were evaluated for age, gender, ED-LOS and admission rate. Rank correlation coefficients were calculated in order to analyze the influence of patient age for each discipline. Statistical tests were performed to evaluate explorative hypotheses on specific discipline influence of patient age.

RESULTS

Patients age significantly differed between the disciplines. There was a strong correlation between patient age and LOS for trauma surgery, visceral surgery and ophthalmology. The correlation between patient age and admission rate was highest in patients with problems regarding internal medicine, trauma surgery and neurology.

CONCLUSION

There is a correlation between patients age, LOS and admission rate in the ED.

Dietary P regulates phosphate transporter expression, phosphatase activity, and effluent P partitioning in trout culture

Phosphate utilization by fish is an important issue because of its critical roles in fish growth and aquatic environmental pollution. High dietary phosphorus (P) levels typically decrease the efficiency of P utilization, thereby increasing the amount of P excreted as metabolic waste in effluents emanating from rainbow trout aquaculture. In mammals, vitamin D3 is a known regulator of P utilization but in fish, its regulatory role is unclear. Moreover, the effects of dietary P and vitamin D3 on expression of enzymatic and transport systems potentially involved in phosphate utilization are little known. We therefore monitored production of effluent P, levels of plasma vitamin D3 metabolites, as well as expression of phosphatases and the sodium phosphate cotransporter (NaPi2) in trout fed semipu diets that varied in dietary P and vitamin D3 levels. Mean soluble P concentrations varied markedly with dietary P but not with vitamin D3, and constituted 40-70% of total effluent P production by trout. Particulate P concentrations accounted for 25-50% of effluent P production, but did not vary with dietary P or vitamin D3. P in settleable wastes accounted for <10% of effluent P. The stronger effect of dietary P on effluent P levels is paralleled by its striking effects on phosphatases and NaPi2. The mRNA abundance of the intestinal and renal sodium phosphate transporters increased in fish fed low dietary P; vitamin D3 had no effect. Low-P diets reduced plasma phosphate concentrations. Intracellular phytase activity increased but brushborder alkaline phosphatase activity decreased in the intestine, pyloric caeca, and gills of trout fed diets containing low dietary P. Vitamin D3 had no effect on enzyme activities. Moreover, plasma concentrations of 25-hydroxyvitamin D3 and of 1,25-dihydroxyvitamin D3 were unaffected by dietary P and vitamin D3 levels. The major regulator of P metabolism, and ultimately of levels of P in the effluent from trout culture, is dietary P.

Release into the environment of metals by two vascular salt marsh plants

Metals in contaminated salt marshes are mainly locked in the anaerobic layer of sediments, where they are tightly bound as sulfides and organic complexes. Vascular plants survive in saturated soils in part by pumping O2 into their root zones, changing their microenvironment to an oxic one. This, along with chelating exudates, mobilizes metals, allowing uptake by the roots. We compared the common reed Phragmites australis and cordgrass Spartina alterniflora in lab and field studies for ways in which they handle trace metals. Both plants store most of their metal burden in their roots, but some is transported to aboveground tissues. Spartina leaves contain approximately 2-3 x more Cr, Pb, and Hg than Phragmites leaves, but equivalent Cu and Zn. Furthermore, Spartina leaves have salt glands, so leaf excretion of all metals is twice that of Phragmites. In-depth studies with Hg indicate that Hg excretion correlates with Na release but not with transpiration, which is 2.2 x higher in Phragmites; and that more Hg accumulates in early-appearing leaves than in upper (i.e. later) leaves in both species. Spartina thus makes more metals available to salt marsh ecosystems than Phragmites by direct excretion and via dead leaves which will enter the food web as detritus.

Development of thyroid abnormalities in mummichogs, Fundulus heteroclitus, from a polluted site

Previous studies showed that adult and 6-month-old young-of-year Fundulus heteroclitus from a polluted site have enlarged thyroid follicles and (in adults) higher thyroxine levels compared to fish from an unpolluted reference site. This study's purpose was to discover when in development these differences begin to appear. For 15-20 mm fish, the average follicle size of the polluted population was significantly larger than that of the reference population, similar to the pattern found in older fish. However, for the smaller size (12-14.5 mm), the average follicle size of fish from the polluted site was significantly smaller. Although not statistically significant, radioimmunoassay measurements of thyroxine levels were consistent with follicle differences: in larger sizes (20-25 and 15-20 mm) fish from the polluted site had higher thyroxine levels but the smaller size (12-14.5 mm) had lower levels. Therefore, the thyroid abnormalities seen in adults begin when the fish are approximately 15-20 mm long. However, the follicle size reversal for the 12-14.5 mm range may also indicate abnormality at that developmental stage.

Hepatic histopathology in two populations of the mummichog, Fundulus heteroclitus

The pollution-tolerant mummichog, Fundulus heteroclitus, inhabits a heavily contaminated estuary, Piles Creek (PC), in Linden, NJ. PC contaminants include PAHs, PCBs and many metals, including high Hg and Pb. PC mummichog livers and kidneys were compared with those from a pristine estuary in Tuckerton (TK), NJ, by standard histopathological methods, with quantification by computerized image analysis. PC livers had > 2 x the lipid ratios of TK livers. Cell sizes and shapes were not different between populations. TK livers had a 25% incidence of basophilic areas and an age-related 30% incidence of macrophage aggregates; PC livers had none of these lesions. PC livers had a 100% incidence of necrotic foci, compared with 55% of TK livers. Inflammation was noted in 50% of TK livers but only 27% of PC livers. Curiously, the TK livers had a 45% incidence of metacercarial cysts of a digenetic trematode, while none were found in the PC livers. The TK focal necrosis and macrophage aggregates coincided with parasite infestation. There were no observed kidney lesions in either population. Positive biomarkers in this species thus included high hepatic lipid content, possibly necrosis, but no other lesions. The lack of trematode cysts in PC livers may reflect the lack of an intermediate host in this low biodiversity estuary.

Lead uptake, distribution, and effects in two dominant salt marsh macrophytes, Spartina alterniflora (cordgrass) and Phragmites australis (common reed)

We examined biomass accumulation, tissue concentrations of lead (Pb), and net uptake of Pb in Phragmites australis (common reed) and Spartina alterniflora (salt cord grass) grown under greenhouse conditions in sediment of different Pb concentrations. Sediment and newly emerged ramets of each plant species were collected in April 1999 from Tuckerton, NJ, a relatively clean salt marsh. One-gallon pots were filled with either control sediment (29 microg g(-1) Pb) or Pb-added sediment (68 microg g(-1) Pb), and the sediment moisture was kept saturated along with controlled additions of additional nutrients. At harvest in October, whole plant biomass was 60-85% greater for pots with P. australis than pots with S. alterniflora and a 40-70% reduction in biomass in response to the addition of Pb was observed for both species. In the high Pb treatments, both concentrations and pools of Pb were greater in the leaves of S. alterniflora than in leaves of P. australis at the end of the growing season. In both species, Pb concentrations were higher in lower leaves than upper leaves. The addition of Pb into experimental pots led to over an 800% increase in Pb standing stock for both species. In S. alterniflora, however, significantly more of this pool was allocated to aboveground biomass (leaves and stems) than to belowground biomass (roots and rhizomes). This difference in allocation was more profound at the higher sediment Pb concentration (Pb-added pots). This fundamental difference between the species in response to Pb contamination indicates that metal export into food webs or the water column should be greater in stands of S. alterniflora than in P. australis. These results suggest that in Pb-contaminated, and possibly all metal-contaminated sediments, the replacement of S. alterniflora with P. australis may reduce metal bioavailability by sequestering a greater proportion of its metal burden in belowground tissues which are likely to be permanently buried.

Dinuclear titanium(IV) complexes from amino acid bridged dicatechol ligands: formation, structure, and conformational analysis

Amino acid bridged dicatechol ligands 3a-e-H4 form dinuclear double-stranded coordination compounds [(3a-e)2Ti2(OCH3)2]2- with titanium(IV) ions. Due to the directionality of the ligands, the chirality of the strand, and the chiral complex units, up to seven isomers, I-VII, can be obtained for the double-stranded complexes of ligands 3a-e-H4. The composition of the mixture of isomeric compounds in solution is strongly dependent on the conditions of complex formation. Under thermodynamic control, only a few isomers are obtained, one of which is the major component of the mixture. X-ray structure analyses were performed for K2[(3b)2Ti2(OH)2] and K2[(3d)2Ti2(OH)2] (type I), and for the meso complex Na2[(3e)(3e')Ti2(OCH3)2]. A conformational analysis that uses Ramachandrans method revealed that the conformation of the amino acids in the ligand strands can be compared with those found for amino acids in helical peptide structures. The most favored isomer of [(3)2Ti2(OCH3)2]2- appears to be of type I, with the catecholamide unit located at the N terminus of the ligand strand that binds to a lambda-configurated titanium(IV) complex unit and the dihydroxybenzyl group at the C terminus that coordinates to a delta-configurated titanium(IV) complex unit. The lambda configuration at the N terminus induces the conformation of a right-handed helix in the amino acid residue, while the delta configuration induces the less favored left-handed helix.

Calcitermin, a novel antimicrobial peptide isolated from human airway secretions

The human airways are protected from pathogenic colonization by a blanket of fluid impregnated with innate antimicrobial effector molecules. Among several previously uncharacterized components, we isolated a peptide that had activity primarily targeting Gram-negative bacteria. We named the peptide 'calcitermin' since its amino acid sequence and mass were equivalent to the 15 C-terminal residues of the S100 protein, calgranulin C. The antimicrobial activity of calcitermin was enhanced in acidic buffers (pH 5.4) and in the presence of micromolar concentrations of ZnCl(2). Analysis revealed a putative zinc-binding consensus sequence as well as an alpha-helical conformation in structure-promoting solvents.

Endocrine disruption: thyroid dysfunction in mummichogs (Fundulus heteroclitus) from a polluted habitat

Mummichogs (Fundulus heteroclitus) from Piles Creeks (PC), New Jersey (a polluted site), are sluggish and show poorer prey capture and predator avoidance than reference fish from Tuckerton (TK). The behavioral dysfunction of the PC fish may be associated with thyroid impairment due to endocrine disruption. In this study, we compared thyroid histology and thyroid hormones in the two populations and determined experimentally whether the polluted environment could alter thyroid hormone levels. PC fish had larger thyroid follicles, greater follicle cell heights, and contained higher plasma thyroxine (T4) levels than TK fish. However, there were no significant differences in either plasma or tissue triiodothyronine (T3). TK fish held in simulated PC environments had higher plasma T4 and lower plasma T3 than field-sampled fish. PC fish held in clean water had lower plasma T4 and T3 than field-sampled fish. In either case, there was no significant difference in tissue T3 content. The contaminants in PC alter thyroid structure and function, which may relate to the behavioral differences between fish from the polluted and reference sites.

Sexually transmitted infections in young pregnant women in Bangui, Central African Republic

In early 1996, 481 women visiting the antenatal services of the 3 major governmental health centres in the capital city of the Central African Republic (CAR) were included in the study. All study participants underwent the health centre's routine gynaecological examination, including laboratory diagnosis of trichomoniasis, candidiasis, gonorrhoea, syphilis and bacterial vaginosis. Cervical secretions and blood samples from study participants were sent to the National STD Reference Centre for diagnosis of Chlamydia trachomatis, Neisseria gonorrhoeae, Candida albicans, Treponema pallidum, and HIV. Overall, 34% of the study women were diagnosed with at least one sexually transmitted infection (STI) (3.1% N. gonorrhoeae, 6.2% C. trachomatis, 9.9% T. vaginalis, 6.7% T. pallidum, 12.2% HIV-1). In addition, 29.1% of women were diagnosed with bacterial vaginosis and 46.6% with candidiasis. Only a small proportion of these women had sought treatment during the weeks before, despite the recognition of genital symptoms. Self-reported and health worker-recognized symptoms, signs and laboratory results exhibited only low sensitivities, specificities, and positive predictive values in the diagnosis of STIs. These findings confirm the high vulnerability of young African women to STIs and emphasize the need for specific control interventions which should include affordable and user-friendly services. Moreover, these results call for more effective quality control in case of laboratory-based STI control strategies and question the validity of syndromic STI management strategies in women attending antenatal care services in Africa.

Application of the ParaSight-F dipstick test for malaria diagnosis in a district control program

A rapid test for the diagnosis of Plasmodium falciparum infections based on the detection of histidine-rich-protein II, the ParaSight-F test, was evaluated after introduction in a district malaria control program in Uganda. Suspected treatment failures, pregnant women and infants with clinical malaria and general fever cases were tested at health facilities in malaria hypo-, meso- and holoendemic areas. A total of 1326 tests were carried out by health unit staff, cross read by experienced laboratory staff and results compared with thick film microscopy as the standard. Rater agreement in reading the dipstick result between health unit staff and laboratory staff was high, kappa index 0.94 (0.88-0.99). Sensitivity was 99.6% (99.0-100) for parasite densities above 500/microl, 98.6% (97.7-99.6) for densities above 50/microl and 22.2% (8.6-42.3) for densities below 10/microl. With the applied testing strategies no differences were found between endemicity levels or patient categories. Specificity was 86.2% (83.3-88.8) overall, but significantly higher in general fever cases (92.7%) compared to the other patient groups (84.3%, P=0.009). At the given prevalences positive predictive values (ppv) were above 80% and negative predictive values (npv) above 90% in all cases except in pregnant women (ppv: 77.8%). We conclude that in certain situations this test is an alternative to microscopy to improve diagnostic facilities for case management in malaria control programs in endemic African countries.

Reductions in risk behaviour provide the most consistent explanation for declining HIV-1 prevalence in Uganda

OBJECTIVE

To monitor the HIV-1 epidemic in Western Uganda and the possible impact of interventions.

DESIGN

Results from sentinel surveillance of HIV-1 seroprevalence were compared with cross-sectional serosurvey data and model simulations.

METHODS

Age-specific trends in HIV-1 prevalence between 1991 and 1997 amongst antenatal clinic (ANC) attenders in the town of Fort Portal, where a comprehensive AIDS control programme has been implemented since 1991, were analysed. Results were compared with outputs from a mathematical model simulating the HIV-1 epidemic in Uganda. Two scenarios were modelled: one without and one with behaviour change. Sentinel surveillance data were compared with data from a population-based HIV-1 serosurvey at the study site, which was carried out in early 1995.

RESULTS

Data from 3271 ANC attenders identified greater education and being single as risk factors for HIV-1 infection. A significant decrease of risk for women with secondary school education over time was observed, whereas the risk for illiterate women remained high. Among women aged 15-19 years (n = 1045) education and marital status-adjusted HIV-1 prevalence declined steadily from 32.2% in 1991 to 10.3% in 1997. For 20-24-year-old women (n = 1010) HIV-1 prevalence increased until 1993 from 19.9% to 31.7% and decreased thereafter (21.7% in 1997). These trends closely follow the prediction of the model simulation assuming behaviour change, and for 1995-1997, confidence intervals of the HIV-1 prevalence estimate exclude the model output for an uninfluenced epidemic. No clear trends of HIV-1 prevalence were found in older women (n = 1216) and comparisons with the model were ambiguous. Sentinel surveillance data at the time of the population survey closely reflected results for the female general population sample for the two younger age-groups (15-19 and 20-24 years). In contrast, pregnant women aged 25-29 years showed significantly lower rates than the population sample (20.8% versus 45.1%).

CONCLUSION

HIV-1 prevalence amongst ANC attenders aged 15-24 years can be used to monitor the HIV-1 epidemic in the given setting. Declining trends of HIV-1 prevalence in women aged 15-19 and 20-24 years most likely correspond to a reduced HIV-1 incidence attributable to changes in behaviour. Our data also show that sentinel surveillance data need to be age-stratified to give useful information.

Ivermectin distribution using community volunteers in Kabarole district, Uganda

Ivermectin mass distribution for the control of onchocerciasis in Uganda began in 1991. This report describes a community based ivermectin distribution programme covering two foci in the Kabarole district which have an estimated 32,000 persons infected and another 110,000 at risk. Through nodule palpation in adult males, 143 villages were identified where nodule prevalence exceeded 20%. Skin snips were also taken from a sample of the population to measure changes in community microfilarial load (CMFL) with treatment. The delivery programme was integrated into the district health management structure, and used community volunteers supervised by medical assistants from adjacent health facilities for annual ivermectin distribution campaigns. After initial efforts by the community to support distributors in-kind proved inadequate, ivermectin distributors earned money retailing condoms as part of the social marketing component of district STD/AIDS programme. Reduction in the CMFL ranged from 40-62% twelve months after the second ivermectin treatment in three villages, and from 69-84% six months after the fourth round of treatment in two villages. After four years of treatment, 85% of eligible persons were receiving ivermectin from community volunteers in each treatment cycle. Drop out rates among volunteers did not exceed 20% over the four years reported here. The direct cost of treatment was US $0.29 per person. Among the reasons for low per-person treatment costs were the strong supervisory structure, the presence of health centres in the foci and a well developed and capable district Primary Health Care management team.

The Extent of Benthic Impacts of CCA-Treated Wood Structures in Atlantic Coast Estuaries

To ascertain the extent of impacts from CCA-treated wood bulkheads, we sampled sediments along 10-m transects from these bulkheads and from reference sites (either bulkheads made of other materials or unbulkheaded areas nearby) and analyzed the fine fraction for metals. We ascertained metal content in resident biota, and analyzed species richness, Shannon-Wiener diversity index, and biomass of the benthic community. We found accumulation of metals in the fine-grained portion of nearby sediments and reduction in the biotic community nearby (generally at 0 and 1 m); such gradients were generally not seen in reference transects. At two of the sites there was evidence for secondary reduction of the community out further to 3 or 10 m, where the metals in the fines were lower but the percent fines was greatly increased. At all the other sites, impacts were generally limited to 0 and 1 m. The lack of reduction at further distances at the other sites is attributed to factors such as the age of the bulkheads, high energy of the environment, or nature of the sediments at those sites.