Sex- and age-specific mercury accumulation in a long-lived seabird

Mercury levels in the environment are increasing, such that they are also expected to accumulate in top-predators, but individual-based longitudinal studies required to investigate this are rare. Between 2017 and 2023, we therefore collected 1314 blood samples from 588 individual common terns (Sterna hirundo) to examine how total blood mercury concentration changed with age, and whether this differed between the sexes. Blood mercury concentrations were highly variable, but all exceeded toxicity thresholds above which adverse health effects were previously observed. A global model showed blood mercury to be higher in older birds of both sexes. Subsequent models partitioning the age effect into within- and among-individual components revealed a linear within-individual accumulation with age in females, and a decelerating within-individual accumulation with age in males. Time spent at the (particularly contaminated) breeding grounds prior to sampling, as well as egg laying in females, were also found to affect mercury concentrations. As such, our study provides evidence that male and female common terns differentially accumulate mercury in their blood as they grow older and calls for further studies of the underlying mechanisms as well as its consequences for fitness components, such as reproductive performance and survival.

Lead exposure by E-waste disposal and recycling in Agbogbloshie, Ghana

BACKGROUND

Agbogbloshie in Ghana is the world's biggest dumpsite for the informal recycling of electronic waste (e-waste). E-waste is dismantled by rudimentary methods without personal or environmental protection. Workers and occupants are exposed to lead. There are no data so far about the extent and the consequences. We therefore analyzed blood lead levels (BLL) and creatinine levels (CL).

METHODS

Full blood samples and basic data (i.e. age, job, length of stay) were collected from dumpsite volunteers. BLL were measured by atomic absorption spectrometry; CL were assessed using the standard clinical laboratory procedures of Aachen Technical University. European BLL reference values were used as Ghana lacks its own. Statistical analysis was by non-parametric tests (Mann-Whitney U test), with p < 0.05.

RESULTS

Participants of both sexes (n = 327; 12-68 years; median age 23 years) were assessed. Most workers were aged <30 years. The collective's BLL was in pathological range for 77.7%; 14% had a BLL >10.0 μg/dl with symptoms consistent with high lead exposure including severe (6.5%) and intermediate (39%) renal disorder. BLL above 15.0 μg/dl were found in 5.9% of all workers which is the German threshold for those working with lead. Elevated CL in a pathological range were found in 254 participants. This is problematic as 75% of the lead entering the body is excreted via urine.

CONCLUSION

Most of our volunteers had pathological BLL and CL. Preventive strategies are necessary to reduce health risks, particularly for vulnerable populations (i.e. children, pregnant women).

Excretion kinetics of 1,3-dichlorobenzene and its urinary metabolites after controlled airborne exposure in human volunteers

The solvent 1,3-dichlorobenzene (1,3-DCB) is formed during thermal decomposition of the initiator 2,4-dichlorobenzoylperoxide in the production of silicone rubber with potential exposure of production workers as shown in previous works. Despite a threshold limit value (MAK value) of 2 ppm in air, there are currently no data about the corresponding internal exposure that would allow for the derivation of a biological limit value. In the present study, we have investigated the absorption of 1,3-DCB and urinary kinetics of its metabolites in 10 human volunteers after controlled inhalative exposure. Due to the strong odour of 1,3-DCB, a subjective evaluation of odour nuisance was also performed. Ten male human volunteers (23-36 yrs.) were exposed 6 h/day to a concentration of 0.7 ppm and 1.5 ppm in the Aachen workplace simulation laboratory (AWSL) with one week between each experiment. In order to investigate potential dermal absorption, the volunteers were exposed to 1.5 ppm wearing a suitable filter mask that prevented inhalative exposure in a third exposure. 1,3-DCB in blood was measured after 3 and 6 h exposure and the urinary metabolites 3,5-dichlorocatechol (3,5-DCC), 2,4-dichlorophenol (2,4-DCP) and 3,5-dichlorophenol (3,5-DCP) were measured over 24 h after exposure via LC/MS/MS. There were clear dose-response relations for all investigated parameters. The maximum excretion of the metabolites was reached at the end of exposure and corresponded to 5.2 ± 0.7 mg/g crea, 1.5 ± 0.35 mg/g crea and 0.07 ± 0.011 mg/g crea at 0.7 ppm and to 12.0 ± 3 mg/g crea, 3.5 ± 1.1 mg/g crea and 0.17 ± 0.05 mg/g crea at 1.5 ppm for 3,5-DCC, 2,4-DCP and 3,5-DCP, respectively. The use of filter masks decreased the internal exposure for about 85-90%, indicating substantial dermal absorption. Odour perception did not show a dose-response, probably due to fast olfactory adaption. The human study presented here provides an excellent basis for deriving a biological limit value for 1,3-DCB.

Mercury contamination level is repeatable and predicted by wintering area in a long-distance migratory seabird

The environmental presence of mercury has dramatically increased over the past century, leading to increased uptake, especially by top predators such as seabirds. Understanding the exact sources of contamination requires an individual-level approach, which is especially challenging for species that migrate. We took such an approach and located the wintering areas of 80 common terns (Sterna hirundo) through tracking, and, across years, collected feathers grown in those areas to assess their mercury levels using atomic absorption spectrometry. Although feathers of males and females did not differ in their mercury level, we found the average feather mercury level to be highest in birds wintering in the Canary Current (3.87 μg g^-1), medium in birds wintering in the Guinea Current (2.27 μg g^-1) and lowest in birds wintering in the Benguela Current (1.96 μg g^-1). Furthermore, we found considerable inter-annual fluctuations in feather mercury levels, a within-individual repeatability of 41%, that the mercury levels of 17% of feather samples exceeded the admitted toxicity threshold of 5 μg g^-1, and that the overall mean concentration of 3.4 μg g^-1 exceeded that of other published reports for the species. Further studies therefore should assess whether these levels lead to individual-level carry-over effects on survival and reproductive performance.

mVEGAS - mobile smartphone-based spatiotemporal gait analysis in healthy and ataxic gait disorders

BACKGROUND

Quantitative gait assessment is increasingly applied in fall risk stratification, diagnosis, and disease monitoring of neuro-geriatric gait disorders. Its broad application, however, demands for low-cost and mobile solutions that facilitate high-quality assessment outside laboratory settings. The aim of this study was to present and evaluate the concurrent validity of a mobile and low-cost gait assessment tool (mVEGAS) that combines body-fixed inertial sensors and a smartphone-based video capture for spatiotemporal identification of gait sequences.

METHODS

Initially, we examined potential interferences of wearing mVEGAS with walking performance in a cohort of 20 young healthy individuals (31.1 ± 10.1 years; 8 females). Subsequently, we assessed the concurrent validity of mVEGAS as compared to a pressure-sensitive gait carpet (GAITRite) in a cohort of 26 healthy individuals (55.8 ± 14.3 years; 10 females) and 26 patients (55.7 ± 14.0; 14 females) with moderate to severe degrees of cerebellar gait ataxia. All participants were instructed to walk at preferred, slow, and fast walking speed and standard average and variability gait measures including velocity, stride length, stride time, base of support, swing and double support phase were examined for agreement between the two systems by absolute error and intraclass correlation coefficients (ICC).

RESULTS

Wearing mVEGAS did only marginally interfere with normal walking behavior. mVEGAS-derived average and variability gait measures exhibited good to excellent concurrent validity in healthy individuals (ICCs ranging between 0.645 and 1.000) and patients with gait ataxia (ICCs ranging between 0.788 and 1.000) SIGNIFICANCE: mVEGAS may facilitate high-quality and long-term gait monitoring in different non-specialized environments such as medical practices, nursing homes or community centers.

New data on the metabolism of chloromethylisothiazolinone and methylisothiazolinone in human volunteers after oral dosage: excretion kinetics of a urinary mercapturic acid metabolite ("M-12")

Methylisothiazolinone (MI) as well as the mixture of chloromethylisothiazolinone/methylisothiazolinone [MCI/MI (3:1)] are biocides that are used in a variety of products of every-day life. Due to the skin sensitizing properties of these biocides, their use has come under scrutiny. We have previously examined the human metabolism of MI and MCI after oral dosage of isotope-labelled analogues in human volunteers and confirmed N-methylmalonamic acid to be a major, but presumably unspecific human urinary metabolite. In the present study, we have investigated the urinary kinetics of a mercapturic acid metabolite of MI and MCI using the same set of samples. Four human volunteers received 2 mg of isotopically labelled MI and MCI separately and at least 2 weeks apart. Consecutive urine samples were collected over 48 h and were examined for the content of the (labelled) 3-mercapturic acid conjugate of 3-thiomethyl-N-methyl-propionamide (“M-12”), a known metabolite in rats. On a molar basis, M-12 represented 7.1% (3.0–10.1%) of the dose excreted in urine after dosage of MI. Excretion of this mercapturate was fast with a mean half-life of 3.6 h. Surprisingly, for MCI the mercapturate M-12 represented only 0.13% of the dose excreted in urine. Thus, this biomarker is highly specific for exposures to MI and might be used to distinguish between different exposure patterns of these biocides [use of MI or MCI/MI (3:1)] in the general population.

Metabolic activation and toxicological evaluation of polychlorinated biphenyls in Drosophila melanogaster

Degradation of polychlorinated biphenyls (PCBs) is initiated by cytochrome P450 (CYP) enzymes and includes PCB oxidation to OH-metabolites, which often display a higher toxicity than their parental compounds. In search of an animal model reflecting PCB metabolism and toxicity, we tested Drosophila melanogaster, a well-known model system for genetics and human disease. Feeding Drosophila with lower chlorinated (LC) PCB congeners 28, 52 or 101 resulted in the detection of a human-like pattern of respective OH-metabolites in fly lysates. Feeding flies high PCB 28 concentrations caused lethality. Thus we silenced selected CYPs via RNA interference and analyzed the effect on PCB 28-derived metabolite formation by assaying 3-OH-2',4,4'-trichlorobiphenyl (3-OHCB 28) and 3'-OH-4',4,6'-trichlorobiphenyl (3'-OHCB 28) in fly lysates. We identified several drosophila CYPs (dCYPs) whose knockdown reduced PCB 28-derived OH-metabolites and suppressed PCB 28 induced lethality including dCYP1A2. Following in vitro analysis using a liver-like CYP-cocktail, containing human orthologues of dCYP1A2, we confirm human CYP1A2 as a PCB 28 metabolizing enzyme. PCB 28-induced mortality in flies was accompanied by locomotor impairment, a common phenotype of neurodegenerative disorders. Along this line, we show PCB 28-initiated caspase activation in differentiated fly neurons. This suggested the loss of neurons through apoptosis. Our findings in flies are congruent with observation in human exposed to high PCB levels. In plasma samples of PCB exposed humans, levels of the neurofilament light chain increase after LC-PCB exposure, indicating neuronal damage. In summary our findings demonstrate parallels between Drosophila and the human systems with respect to CYP mediated metabolism and PCB mediated neurotoxicity.

Quantification of six potential unspecific human biomarkers of 1-vinyl-2-pyrrolidone exposure in Sprague-Dawley rat urine using gas chromatography coupled with triple mass spectrometry

RATIONALE

The monomer 1-vinyl-2-pyrrolidone (VP) is a substance with excellent solvent features. It is used in a wide variety of pharmaceutical, cosmetic, food industrial or technical applications and produced on an industrial scale. Since VP has caused adenocarcinoma of the nasal cavity and liver cell carcinoma in long-term experiments with rats, a human biomarker would be appreciated for risk assessment.

METHODS

A sensitive analytical electron ionization gas chromatography/tandem mass spectrometry (GC/MS/MS) method for the determination of six possible biomarkers for VP in urine was established and validated. Two isotope-labeled internal standards (ISTD) were used for quantification. A simple and easy to use freeze-drying step was performed prior to derivatization with N-tert-butyldimethylsilyl-N-methyltrifluoracetamide (MTBSTFA) and following sample extraction for cleanup purposes.

RESULTS

A calibration curve with six calibration standards ranging from 50 μg/L to 2000 μg/L (10-fold higher for H-OPAA) in urine was prepared. Validation results were satisfactory with recoveries ranging from 88.2 to 110.2 % with two exceptions for the lowest quality control for two substances without ISTD (126.4 % and 139.3 %). Three of the substances could be identified as VP metabolites in an exposure study with Sprague-Dawley (SD) rats.

CONCLUSIONS

A quick and easy to use method has been established for six target molecules investigated for a better understanding of the metabolism of VP. Two of three substances identified as metabolites of VP could serve as a nonspecific human biomarker for VP exposure as shown with an excerpt of an exposure study performed in SD rats.

Predicting patterns of long-term adaptation and extinction with population genetics

Population genetics struggles to model extinction; standard models track the relative rather than absolute fitness of genotypes, while the exceptions describe only the short-term transition from imminent doom to evolutionary rescue. But extinction can result from failure to adapt not only to catastrophes, but also to a backlog of environmental challenges. We model long-term adaptation to long series of small challenges, where fitter populations reach higher population sizes. The population's long-term fitness dynamic is well approximated by a simple stochastic Markov chain model. Long-term persistence occurs when the rate of adaptation exceeds the rate of environmental deterioration for some genotypes. Long-term persistence times are consistent with typical fossil species persistence times of several million years. Immediately preceding extinction, fitness declines rapidly, appearing as though a catastrophe disrupted a stably established population, even though gradual evolutionary processes are responsible. New populations go through an establishment phase where, despite being demographically viable, their extinction risk is elevated. Should the population survive long enough, extinction risk later becomes constant over time.

Isotope-dilution method for the determination of 1-vinyl-2-pyrrolidone-mercapturic acid as a potential human biomarker for 1-vinyl-2-pyrrolidone via online SPE ESI-LC/MS/MS in negative ionization mode

We established and validated a specific and sensitive analytical method for the determination of 1-vinyl-2-pyrrolidone (VP) as 1-vinyl-2-pyrrolidone-mercapturic acid (VPMA) in urine using an electrospray liquid chromatography tandem mass spectrometry (ESI-LC/MS/MS) column switching method. An online solid phase extraction (SPE) for sample cleanup was performed by column switching to a restricted access material and back-flushing to the analytical column. A Phenomenex Luna C8 column was used for sample separation (150mm; ID 4,6mm; 3μm). D4-VPMA served as an isotope labeled internal standard and was detected in negative multiple-reaction monitoring (MRM) mode. The Limit of quantification (LOQ) for VPMA was 1.5μg/L, the intra-day precision of three concentrations (2μg/L, 75μg/L and 400μg/L) of spiked urine samples ranged from 2.7 to 7.3%, the inter-day precision from 3.4 to 14.4%. The accuracy ranged from 6.2 to 9.0%, for the intra-day experiments and from 0.3 to 6.9% for the inter-day experiments. The method was applied to urines of Sprague-Dawley rats exposed to VP as a proof of principle of VPMA as a potential biomarker.

Biological effects of inhaled nitrogen dioxide in healthy human subjects

PURPOSE

Several epidemiological studies indicate that inhaled nitrogen dioxide (NO2) at low concentrations have been statistically associated with adverse health effects. However, these results are not reflected by exposure studies in humans. The aim of the study was to assess the acute functional and cellular responses to different NO2 concentrations in healthy human subjects with various techniques.

METHODS

Twenty-five subjects were exposed for 3 h to NO2 concentrations 0, 0.1, 0.5, and 1.5 ppm in a randomized crossover study design during 4 consecutive weeks. In each subject, lung function, diffusion capacity and exhaled nitric oxide were measured and inflammation markers were assessed in blood, nasal secretions, induced sputum and exhaled breath condensate.

RESULTS

From all lung function indices under consideration, only intrathoracic gas volume was borderline significantly increased after 0.5 ppm (p = 0.048) compared to 0.1 ppm NO2. Regarding the cellular effect parameters, the macrophage concentration in induced sputum decreased with increasing NO2 concentration, although these changes were only borderline significant (p = 0.05).

CONCLUSION

These results do not suggest a considerable acute adverse response in human subjects after 3 h of exposure to NO2 in the NO2 concentration range investigated in this study.

Assessment of the biological effects of welding fumes emitted from metal inert gas welding processes of aluminium and zinc-plated materials in humans

The aim of this study was to investigate biological effects and potential health risks due to two different metal-inert-gas (MIG) welding fumes (MIG welding of aluminium and MIG soldering of zinc coated steel) in healthy humans. In a threefold cross-over design study 12 male subjects were exposed to three different exposure scenarios. Exposures were performed under controlled conditions in the Aachener Workplace Simulation Laboratory (AWSL). On three different days the subjects were either exposed to filtered ambient air, to welding fumes from MIG welding of aluminium, or to fumes from MIG soldering of zinc coated materials. Exposure was performed for 6 h and the average fume concentration was 2.5 mg m(-3). Before, directly after, 1 day after, and 7 days after exposure spirometric and impulse oscillometric measurements were performed, exhaled breath condensate (EBC) was collected and blood samples were taken and analyzed for inflammatory markers. During MIG welding of aluminium high ozone concentrations (up to 250 μg m(-3)) were observed, whereas ozone was negligible for MIG soldering. For MIG soldering, concentrations of high-sensitivity CRP (hsCRP) and factor VIII were significantly increased but remained mostly within the normal range. The concentration of neutrophils increased in tendency. For MIG welding of aluminium, the lung function showed significant decreases in Peak Expiratory Flow (PEF) and Mean Expiratory Flow at 75% vital capacity (MEF 75) 7 days after exposure. The concentration of ristocetin cofactor was increased. The observed increase of hsCRP during MIG-soldering can be understood as an indicator for asymptomatic systemic inflammation probably due to zinc (zinc concentration 1.5 mg m(-3)). The change in lung function observed after MIG welding of aluminium may be attributed to ozone inhalation, although the late response (7 days after exposure) is surprising.

MATra - Magnet Assisted Transfection: Combining Nanotechnology and Magnetic Forces to Improve Intracellular Delivery of Nucleic Acids

Recent efforts combining nanotechnology and magnetic properties resulted in the development and commercialization of magnetic nanoparticles that can be used as carriers for nucleic acids for in vitro transfection and for gene therapy approaches including DNA-based vaccination strategies. The efficiency of intracellular delivery is still a limiting factor for basic cell biological research and also for emerging technologies such as temporary gene silencing based on inhibitory RNA/siRNA. Nanotechnology has resulted in a variety of different nanostructures and especially nanoparticles as carriers in a wide range of new drug delivery systems for conventional drugs, recombinant proteins, vaccines and more recently nucleic acids. It is possible to combine superparamagnetic nanoparticles with magnetic forces to increase, direct and optimize intracellular delivery of biomolecules. This article discusses the main approaches in the field of magnet assisted transfection (MATra) focusing on the transfection or intracellular delivery of nucleic acids, although also suitable to improve the intracellular delivery of other biomolecules.

MS-Register in Deutschland — Design und erste Ergebnisse der Pilotphase

In the summer of 2001, a nationwide epidemiological multiple sclerosis (MS) register was initiated under the auspices of the German MS Society (DMSG). This project aimed at collecting epidemiological data on the number of patients with MS, course of the disease, and their social situation in Germany. During the 2-year pilot phase, five MS centers with various regional differences and treatment methods participated, leading to a representative selection of patients. In December 2003, standardised data sets of 3,458 MS patients were available for evaluation. After examining the quality of the data, 3,223 sets remained for further analysis. The demographics were similar to those obtained from other epidemiological studies: 72% of the patients were female, mean age was 42.9+/-11.2 years, mean disease duration 12.6+/-8.7 years, and 64% suffered from the relapsing-remitting form of the disease. The median EDSS was 3.0, and 69% of patients had an EDSS </=4.0. The great effect of this disorder was underscored by the fact that one third of the patients had prematurely retired due to MS. After successful completion of the pilot phase, the MS register will provide reliable data and thus serve as an important tool to improve the overall situation of MS patients in Germany.

Temporal and spatial transcriptional programs in murine kidney development

We have performed a systematic temporal and spatial expression profiling of the developing mouse kidney using Compugen long-oligonucleotide microarrays. The activity of 18,000 genes was monitored at 24-h intervals from 10.5-day-postcoitum (dpc) metanephric mesenchyme (MM) through to neonatal kidney, and a cohort of 3,600 dynamically expressed genes was identified. Early metanephric development was further surveyed by directly comparing RNA from 10.5 vs. 11.5 vs. 13.5dpc kidneys. These data showed high concordance with the previously published dynamic profile of rat kidney development (Stuart RO, Bush KT, and Nigam SK. Proc Natl Acad Sci USA 98: 5649-5654, 2001) and our own temporal data. Cluster analyses were used to identify gene ontological terms, functional annotations, and pathways associated with temporal expression profiles. Genetic network analysis was also used to identify biological networks that have maximal transcriptional activity during early metanephric development, highlighting the involvement of proliferation and differentiation. Differential gene expression was validated using whole mount and section in situ hybridization of staged embryonic kidneys. Two spatial profiling experiments were also undertaken. MM (10.5dpc) was compared with adjacent intermediate mesenchyme to further define metanephric commitment. To define the genes involved in branching and in the induction of nephrogenesis, expression profiling was performed on ureteric bud (GFP+) FACS sorted from HoxB7-GFP transgenic mice at 15.5dpc vs. the GFP- mesenchymal derivatives. Comparisons between temporal and spatial data enhanced the ability to predict function for genes and networks. This study provides the most comprehensive temporal and spatial survey of kidney development to date, and the compilation of these transcriptional surveys provides important insights into metanephric development that can now be functionally tested.

Effects of hexadecylphosphocholine on thrombocytopoiesis

Hexadecylphosphocholine (HePC) is the first representative of the alkylphosphocholines, a novel group derived from the cytotoxic etherlysophospholipids. HePC shows a broad spectrum of antiproliferative effects in neoplastic cells in vitro and in vivo. HePC has been tested successfully in several clinical studies. One of the remarkable features of this compound has been the induction of a leucocytosis and a thrombocytosis in most of the patients receiving HePC systemically. In this paper, we have investigated the biological and molecular mechanisms by which HePC exerts this interesting effect. We found that HePC acts as an unspecific costimulator on human megakaryocytic proliferation in a soft agar assay system predominantly together with thrombopoietin (TPO). Furthermore, HePC leads to the synthesis and secretion of several haematopoietic growth factors in monocytes and bone marrow fibroblasts, determined by the direct measurement of growth factors in cellular supernatants and by the measurement of growth factor mRNA in cell extracts. Thus, HePC seems to produce the increase of blood platelets in tumour patients by two different mechanisms.

Suppressive subtractive hybridisation reveals differential expression of serglycin, sorcin, bone marrow proteoglycan and prostate-tumour-inducing gene I (PTI-1) in drug-resistant and sensitive tumour cell lines of haematopoetic origin

The development of therapy-induced drug resistance is still one of the most important therapeutic limitations. Nevertheless, an integrating view of the molecular mechanisms underlying resistance development in general is missing. In order to shed some light on the network of this resistance development, we established drug-resistant (doxorubicin (DX), methotrexate (MTX), cisplatin (cisPt), vincristine (Vin)) derivatives of six tumour cell lines (Jurkat, U937, HL60, DoHH-2, K562 and ARH77) of haematopoetic origin. Differential gene expression of drug-sensitive parental cell lines and the drug-resistant derivatives thereof was analysed by suppressive subtractive hybridisation. After dot blot screening for differential expression and sequencing of the cloned PCR fragments, differential expression was confirmed by Northern blot analysis. In an attempt to discriminate for differentially expressed genes only related to one or the other of the investigated drugs, the cDNAs of various resistant sublines (doxorubicin-, methotrexate-, cisplatin-resistant Jurkat cells) were pooled and compared with the sensitive parental cell line. In addition, cDNAs of the resistant derivatives of the different haematopoetic tumour cell lines were pooled and compared with the pooled cDNAs of the corresponding sensitive haematopoetic cell lines to eliminate cell line to cell line variations that were not related to drug resistance. As a result of this screening, the following genes showed a higher (at least 2-fold) or exclusive expression in the drug-resistant variants: serglycin, sorcin, BMPG (bone marrow proteoglycan gene) and PTI-1 (prostate-tumour-inducing gene 1). In addition, elevated expression of hsp90, previously found by our group to be upregulated in the drug-resistant colon carcinoma cell line LoVo H67P was found to be overexpressed in drug-resistant HL60 cells.

A pilot study using a staph protein A column (Prosorba) to treat refractory rheumatoid arthritis

OBJECTIVE

To assess the safety and effectiveness of extracorporeal treatments with protein A (Prosorba) columns in the treatment of patients with severe refractory rheumatoid arthritis (RA) in an open label pilot study.

METHODS

Fifteen patients with RA who had failed to respond to 2 or more disease modifying antirheumatic drugs were "washed out" for 1-3 months before enrollment into this 6 month pilot study. The treatment schedule called for patients to receive apheresis treatments across staphylococcal protein A columns once a week for 12 weeks. Clinical evaluations of RA activity, defined by Paulus criteria, were conducted at study enrollment (baseline) and monthly throughout the treatment phase. In addition, examinations were conducted at 2, 4, 8, and 12 weeks after the last treatment. Fourteen patients received all 12 scheduled treatments, while one patient received only 10 treatments due to complications secondary to pneumonia.

RESULTS

Using Paulus 50% criteria, 9 of 15 (60%) patients were improved at the 4th month, and one more fulfilled >20% Paulus criteria (7%) in the 5th month after starting therapy. The study group reported an average of 2.47 adverse effects per treatment, of which the most common were joint pain and swelling and fatigue of short duration (arthritic flare).

CONCLUSION

The adverse effects associated with this apheresis based treatment proved to be manageable and of short duration and resolved without sequelae. The results suggest that extracorporeal protein A therapy may have a role in the management of refractory RA, and encouraged the initiation of a larger, blinded, controlled clinical trial.

Elevated expression of S100P, CAPL and MAGE 3 in doxorubicin-resistant cell lines: comparison of mRNA differential display reverse transcription-polymerase chain reaction and subtractive suppressive hybridization for the analysis of differential gene expression

Subtractive suppressive hybridization (SSH) and mRNA differential display reverse transcription-polymerase chain reaction (DDRT-PCR) were compared for their ability to detect the expression of drug-resistance associated genes in a doxorubicin-resistant and -sensitive colon carcinoma cell line (LoVo H67P). The expression pattern of more than 9000 bands obtained by DDRT-PCR were identical in both cell lines by more than 95%. Of the remaining differentially expressed DDRT-PCR products, 21 cDNA fragments were further analyzed after cloning. A total of 210 clones were sequenced resulting in 40 different sequences of which only five were differentially expressed as revealed by Northern blot analysis. SSH, on the other hand, resulted in 30 different sequences of 37 clones analyzed. Thirteen of 30 sequences (43%) could be identified by databank analysis (excluding expressed sequence tags) in contrast to nine of 40 clones (23%) obtained by DDRT-PCR. Of the clones identified by SSH, 60% exhibited a differential expression comparing the doxorubicin-resistant and -sensitive cell line, respectively, as compared to only 13% of the DDRT-PCR derived clones. The application of SSH resulted in the identification of differentially expressed genes in three doxorubin-resistant cell lines (LoVo DxR, ARH D60 and KB-V1) as compared to the sensitive parental cell lines. A significant higher expression of S100P, a protein involved in calcium metabolism, as well as MAGE 3 (melanoma antigen gene) was found in the resistant cell lines using this methodology. The expression of CAPL, a second protein involved in calcium metabolism, was only moderately elevated in the doxorubicin-resistant cells. We found that subtractive suppressive hybridization proved to be a more rapid and reliable method for the detection of differentially expressed mRNAs in our system.

Overexpression of ribosomal proteins L4 and L5 and the putative alternative elongation factor PTI-1 in the doxorubicin resistant human colon cancer cell line LoVoDxR

A better understanding of the regulatory network underlying cellular drug resistance and stress response may be helpful to overcome the phenomenon of therapy-induced cross-resistances against a variety of antineoplastic agents. Two new powerful molecular techniques, mRNA differential display reverse transcriptase polymerase chain reaction (DDRT-PCR) and subtractive suppressive hybridisation were applied for the comparative analysis of the gene expression profile of a doxorubicin resistant and its corresponding sensitive parental colon carcinoma cell line (LoVo H67P). DDRT-PCR generated partial cDNAs from the doxorubicin resistant, sensitive and stress (dexamethasone, doxorubicin, cadmium chloride or heat) exposed sensitive cells, were size-separated on polyacrylamide gels. The expression patterns of more than 9000 bands of the resistant, sensitive and stressed sensitive cell populations were identical by more than 95%. Of the differentially expressed mRNAs, 20 cDNA fragments were reamplified after isolation from the gel, used as probes for Northern blot analysis to verify their differential expression and sequenced after cloning. Among the differentially expressed cDNAs, homologies of 96% and 87%, respectively, were found to the human proto-oncogene PTI-1 and the human ribosomal protein L4. Subtractive suppressive hybridisation revealed overexpression of the ribosomal protein L5 in the doxorubicin resistant line. These data point to the control of gene expression at the translational level as an important mechanism involved in cellular stress response.

Automated high resolution PCR fragment analysis for identification of clonally rearranged immunoglobulin heavy chain genes

The development of rapid polymerase chain reaction (PCR) protocols for amplification of rearranged heavy chain immunoglobulin (IgH) gene sequences has facilitated the identification of clonal IgH rearrangements in non-Hodgkin's lymphomas (NHL) and leukemias of B lineage. In the present report we have explored the recently described improved strategy for assessment of clonality of rearranged immunoglobulin heavy chain (IgH) genes in more detail in a series of 101 B cell malignancies and 50 polyclonal controls. The assay is based on an IgH-PCR with an automated fluorescence-based strategy for PCR detection of IgH gene rearrangements. Third complementarity determining region (IgH-CDR3) sequences were amplified using fluorescent dye labeled consensus primers homologous to the corresponding variable (V[H]) and joining (J[H]) gene segments in combination with a thermostable proofreading DNA polymerase. PCR products were size separated on a high resolution polyacrylamide gel and analyzed for clonality by exact size determination and fluorescence quantification in an automated DNA sequencer. PCR findings obtained with the optimized IgH-CDR3-PCR assay showed an overall monoclonality detection rate of 97% (97 of 101 cases with B cell neoplasms). The specificity was 100% as determined by analysis of 50 controls, all of which gave polyclonal PCR results. We found a high rate of monoclonal IgH-CDR3-PCR results not only in the leukemias and diffuse lymphoma but also in the group of follicular lymphoma, where a high rate of false negative results is frequently reported in the literature. In summary, we identified monoclonal IgH-CDR3 junctions in 55 out of 59 cases (93%) with B cell lymphoma and in 42 of 42 (100%) cases with leukemia, immunocytoma and multiple myeloma. The results demonstrate that automated fluorescence detection of IgH-CDR3-PCR products is an ideal tool for detection of clonal and polyclonal lymphoid B cells. In combination with allele-specific primers the procedure may improve current experimental approaches to detect occult malginant B cells during initial staging and follow-up of NHL and ALL patients.

Variations in composition of cartilage from the shoulder joints of young adult dogs at risk for developing canine hip dysplasia

OBJECTIVE

To determine whether the composition of cartilage from the shoulder joints of dogs varied with the risk of developing canine hip dysplasia (CHD).

DESIGN

Observational study.

ANIMALS

12 skeletally mature (approx 1 year old) Labrador Retrievers.

PROCEDURE

Dogs were classified as having a low, moderate, or high risk of developing CHD on the basis of distraction indices. Cartilage was harvested from the craniolateral and weight-bearing regions of the humeral heads, and wet weight per unit area and dry, glycosaminoglycan, and fibronectin contents were determined.

RESULTS

Glycosaminoglycan and dry contents did not vary among risk groups. For cartilage from the craniolateral region of the humeral head, wet weight per unit area and fibronectin content increased as risk of developing CHD increased. Wet weight and fibronectin content of cartilage from the weight-bearing region of the humeral head did not vary among risk groups.

CLINICAL IMPLICATIONS

Dogs that have a high risk of developing CHD are also more likely to develop osteoarthritis of the shoulder joint. The observed increases in wet weight per unit area and fibronectin content in cartilage from the craniolateral region of the humeral head in dogs at a high risk of developing CHD may be early sings of incipient osteoarthritis.

Cardiac phase-synchronized myocardial thallium-201 single-photon emission tomography using list mode data acquisition and iterative tomographic reconstruction

The purpose of this study was to determine whether data acquisition in the list mode and iterative tomographic reconstruction would render feasible cardiac phase-synchronized thallium-201 single-photon emission tomography (SPET) of the myocardium under routine conditions without modifications in tracer dose, acquisition time, or number of steps of the a gamma camera. Seventy non-selected patients underwent 201T1 SPET imaging according to a routine protocol (74 MBq/2 mCi 201T1, 180 degrees rotation of the gamma camera, 32 steps, 30 min). Gamma camera data, ECG, and a time signal were recorded in list mode. The cardiac cycle was divided into eight phases, the end-diastolic phase encompassing the QRS complex, and the end-systolic phase the T wave. Both phase- and non-phase-synchronized tomograms based on the same list mode data were reconstructed iteratively. Phase-synchronized and non-synchronized images were compared. Patients were divided into two groups depending on whether or not coronary artery disease had been definitely diagnosed prior to SPET imaging. The numbers of patients in both groups demonstrating defects visible on the phase-synchronized but not on the non-synchronized images were compared. It was found that both postexercise and redistribution phase tomograms were suited for interpretation. The changes from end-diastolic to end-systolic images allowed a comparative assessment of regional wall motility and tracer uptake. End-diastolic tomograms provided the best definition of defects. Additional defects not apparent on non-synchronized images were visible in 40 patients, six of whom did not show any defect on the non-synchronized images. Of 42 patients in whom coronary artery disease had been definitely diagnosed, 19 had additional defects not visible on the non-synchronized images, in comparison to 21 of 28 in whom coronary artery disease was suspected (P < 0.02; chi 2). It is concluded that cardiac phase-synchronized 201T1 SPET of the myocardium was made feasible by list mode data acquisition and iterative reconstruction. The additional findings on the phase-synchronized tomograms, not visible on the non-synchronized ones, represented genuine defects. Cardiac phase-synchronized 201T1 SPET is advantageous in allowing simultaneous assessment of regional wall motion and tracer uptake, and in visualizing smaller defects.

Increase of P-glycoprotein-mediated drug resistance by hsp 90 beta

The expression of heat shock proteins hsp27, hsp60, hsp70, hsp90 alpha and hsp90 beta in extracts of three cell lines (LoVo DxR, KBChR8-5 and S180 DxR) expressing the MDR (multidrug resistance) positive phenotype as well as in the sensitive parental lines has been investigated. We present evidence that heat shock protein hsp90 beta is associated with the P-glycoprotein (Pgp or P170) one of the most prominent components of the drug resistance machinery. In the doxorubicin-resistant cell line LoVo DxR, but not in the sensitive parental line, hsp90 beta is expressed constitutively as shown by Northern blotting. The expression of hsp90 beta in the sensitive LoVo cell line, however, can be induced by exposure of the doxorubicin-sensitive parental cell line to different stress factors (dexamethasone, doxorubicin, heat treatment or cadmium chloride). We were able to demonstrate that hsp90 beta can be co-precipitated along with Pgp and vice versa. In native agarose gels both proteins migrated together as one single band as shown by Western blot analysis. This intracellular protein-protein interaction may present a mechanism for the modulation of Pgp function possibly by a stabilization of the protein which seems to be attributed to hsp90 beta (in the human colon carcinoma cell line and in the murine cell line S180). Antisense experiments with oligonucleotides directed against hsp90 beta and Pgp, respectively, showed a synergistic effect of the selected hsp90 beta antisense oligonucleotide in combination with the previously described Pgp antisense oligonucleotide in reducing the doxorubicin resistance. The hsp90 beta antisense oligonucleotide when applied in addition to the Pgp antisense oligonucleotide increased the doxorubicin sensitivity of the resistant human colon carcinoma cell line 2-fold. On the contrary, the hsp90 beta antisense oligonucleotide alone in contrast to the Pgp antisense oligonucleotide alone did not cause a reduction of the chemoresistance. Moreover, Pgp half-life was reduced in the presence of both antisense oligonucleotides as compared with an incubation with an anti-Pgp antisense oligonucleotide alone.

Swelling and fibronectin accumulation in articular cartilage explants after cyclical impact

The objective of this study was to determine if repeated impact could damage living cartilage and lead to osteoarthritis-like changes in its biology. Canine cartilage explants were subjected to impacts of as much as 50 MPa once every 5 seconds for 30 minutes. On each impact cycle, the loading rate was 100 MPa/sec to the assigned peak stress, which was held for 1 second. After impact testing, the cartilage was kept in defined culture for as long as 10 days. Radiosulfate incorporation in the region that received direct impact varied with load 0-4 hours after impact, but it did not vary with load at 20-24 hours after impact. Even so, most explants were visibly damaged by 20 or 50 MPa, and there was subtle evidence of damage from impacts of 5 or 10 MPa. For example, ion-induced swelling in 0.01 M NaCl was increased, suggesting that the physical integrity of the matrix was reduced relative to controls. Self-diffusion of water, measured by proton magnetic resonance imaging was also increased in the deeper zones of the explant, consistent with changes in structure at the molecular level. Ten days after impact, the water content and the fibronectin content of the loaded region of the explant were both increased. In combination, these osteoarthritis-like changes suggested that the physical strength of normal cartilage limits its ability to withstand cyclical impact.

Short technical reports. Quantification of ribozyme-mediated RNA cleavage using silver-stained polyacrylamide gels

A very sensitive, nonradioactive method for the detection of ribozymes, targets for ribozyme cleavage and cleavage products with subsequent densitometric quantification of RNA, has been developed. Amounts as low as 15 ng--corresponding to 0.16 pmol of a 300-nucleotide RNA molecule--can be visualized in denaturating polyacrylamide (PA) gels. This sensitive method allows analysis and quantification of ribozyme-mediated cleavage of in vitro-transcribed short stretches of RNA. The substitution of N'N'-methylene bisacrylamide by piperazine diacrylamide in the PA gels to improve signal-to-noise ratio could not further optimize the contrast. Sensitivity was dependent on the presence of urea in the gel and could be increased 4-fold in a gel without urea.