A large-scale study of microplastic abundance in sediment cores from the UK continental shelf and slope

To inform risk assessments, reliable, time efficient and affordable quantification methods are required for creating a microplastic (MP) pollution baseline in the world's oceans. To facilitate this, MP abundance was investigated in sediments of three contrasting areas of the UK continental shelf: North West of Jones Bank, the Canyons in the Celtic Sea and Dogger Bank in the North Sea, utilising the Nile Red tagging method to assess its time efficiency and cost. Average MP abundance in the top 10 cm was 1050-2700 MP kg^-1. MP abundance decreased with increasing sediment depth and increased with increasing water depth. The findings emphasise the extent of MP pollution and illustrate the value of Nile Red for large scale mapping at relatively low cost.

Quality of cochlear implant rehabilitation under COVID-19 conditions

Background

The rehabilitation process following cochlear implant (CI) surgery is carried out in a multimodal therapy according to German national guidelines and includes technical and medical aftercare. In times of the corona pandemic surgery and rehabilitation appointments were cancelled or delayed leading to a more difficult access to auditory rehabilitation. Newly implemented hygiene modalities due to the SARS-CoV‑2 pandemic have changed medical aftercare and the rehabilitation process. The aim of this study was to evaluate the quality of rehabilitation under corona conditions.

Material and methods

An anonymous survey of adult cochlear implant patients was carried out by a non-standardized questionnaire. Demographics were analyzed and the quality of medical aftercare, speech therapy, technical aftercare, psychological support and the hygiene modalities were compared to previous rehabilitation stays.

Results

In total 109 patients completed the questionnaire. The quality of rehabilitation and individual therapy were rated as qualitatively similar or improved. The threat of the pandemic and fear of corona were rated unexpectedly high with 68% and 50%, respectively. The hygiene measures during the rehabilitation stay eased subjective fears at the same time. The majority of patients were annoyed by wearing face masks but visors, protection shields and social distancing were more tolerated.

Conclusion

The implementation of the new hygiene modalities within the therapeutic rehabilitation setting was well-accepted by patients allowing access to auditory rehabilitation. A successful rehabilitation should ensure a fear-free environment by adhering to the necessary hygiene modalities.

Electronic supplementary material

The online version of this article (10.1007/s00106-020-00923-z) includes the study questionnaire. Article and supplementary material are available at www.springermedizin.de. Please enter the title of the article in the search field, the supplementary material can be found under “Ergänzende Inhalte”.

[Quality of cochlear implant rehabilitation under COVID-19 conditions. German version]

Hintergrund

Die Rehabilitation nach CI(Cochleaimplantat)-Operation erfolgt leitliniengerecht durch eine multimodale Therapie, technische Anpassungen des Sprachprozessors und medizinische Nachsorge. Zu Zeiten der Corona-Pandemie wurde für die Patienten der Zugang zur auditorischen Rehabilitation verzögert oder erschwert. Die neuen Hygienemaßnahmen durch die SARS-Cov-2-Pandemie verändern auch die medizinische Nachsorge und Rehabilitation nach CI. Ziel der Untersuchung war es, die Qualität der Rehabilitation unter Corona-Bedingungen zu evaluieren.

Material und Methoden

Wir führten eine anonyme Befragung erwachsener Rehabilitanden mittels nichtstandardisiertem Fragebogen durch. Beurteilt wurden im Vergleich zu den Voraufenthalten die Qualität der ärztlichen Betreuung, der Sprach- und Musiktherapie, der technischen Anpassung und der psychologischen Betreuung sowie der Einsatz der Hygienemaßnahmen.

Ergebnisse

Insgesamt 109 Rehabilitanden beantworteten den Fragebogen. Die Qualität der Rehabilitation und der Therapien wurde als qualitativ unverändert oder besser eingeschätzt. Die Gefährlichkeit der Pandemie, aber auch die Angst in der derzeitigen Situation gaben die Rehabilitanden zu einem unerwartet hohen Prozentsatz mit 68 bzw. 50 % an. Gleichzeitig konnten die getroffenen Hygienemaßnahmen die Patienten subjektiv während des Aufenthalts entlasten. Der Mund-Nasen-Schutz war für die Mehrheit sehr störend, Visiere, Spuckschutz bzw. Abstandsgebot wurden eher toleriert.

Schlussfolgerungen

Die Umsetzung der Hygienemaßnahmen im therapeutischen Setting der CI-Rehabilitation wird von den Rehabilitanden akzeptiert und erlaubt den Zugang zur auditorischen Rehabilitation. Ziel einer erfolgreichen CI-Rehabilitation sollte eine möglichst angstfreie Behandlung unter Wahrung der Hygieneregeln sein.

Zusatzmaterial online

Die Online-Version dieses Beitrags (10.1007/s00106-020-00922-0) enthält den Studienfragebogen. Beitrag und Zusatzmaterial stehen Ihnen auf www.springermedizin.de zur Verfügung. Bitte geben Sie dort den Beitragstitel in die Suche ein, das Zusatzmaterial finden Sie beim Beitrag unter „Ergänzende Inhalte“.

Effects of isoquinoline alkaloids from Macleaya cordata on physiological, immunological and inflammatory parameters in healthy beagles: Alkaloids in dog nutrition

The aim of the study was to investigate nutritional, physiological and immunological effects of a plant-derived blend of isoquinoline alkaloids (Sangrovit® Extra) in healthy dogs. Two groups of healthy, adult beagles (N = 10) were tested in a cross-over experiment, lasting two consecutive three-week periods. The experimental group received 1.2 g additive/kg feed, according to the recommendation of 10-20 mg/kg live weight per day. The control group received the same feed without additive. Complete blood count, immunological parameters and amino acid concentrations in serum were assessed. Faeces were analysed for short-chain fatty acids, lactate and ammonium; moreover, their quantity and consistency were determined. Neither feed intake, total apparent nutrient digestibility (crude protein and fat, organic matter, sodium, potassium) were affected by intake of the product. Lymphocyte and monocyte counts were slightly increased in both groups. Elevation was not treatment dependant. IgA, IgG, haptoglobin in serum and flow cytometric phenotyping of peripheral lymphocytes were not affected by alkaloids supplementation. Numerically greater methionine concentrations in blood serum occurred in the experimental group (p = 0.182). Quantity and consistency of faeces and ammonium concentration in faeces were not affected by the additive. Faecal concentrations of short-chain organic acids differed between groups (acetic acid, % of total SCFA: control group 52.3 ± 5.2 vs. experimental group 57.1 ± 4.5, p = 0.042), lactate concentrations (d-, l- and total) did not. Due to the shift of SCFA proportions in faeces, an effect of isoquinoline alkaloids (IQs) on the metabolic activity of intestinal microbiota is probable. In conclusion, the addition of IQs in the given dose was well tolerated and did not have adverse effects in healthy dogs.

Influence of differently processed yeast (Kluyveromyces fragilis) on feed intake and gut physiology in weaned pigs

Two feeding trials were conducted to investigate the effects of hydrolyzed (HY) or non-hydrolyzed (NHY) yeast (Kluyveromyces fragilis) in isoenergetic and isonitrogeneous diets in the postweaning period. In experiment 1, a total of 550 unsexed pigs (6.5 ± 0.5 kg BW), weaned at 24 ± 2 d of age, were allocated to five treatment groups, receiving either a control diet (CON) or diets with 1%, 3%, and 5% HY (groups HY1, HY3, and HY5, respectively), or a diet with 3% NHY (group NHY3). In experiment 2, a total of 48 male and female pigs (6.2 ± 0.3 kg BW, weaned at d 25) were allocated to three dietary groups (n = 8 replicates with two pigs) receiving a control diet (CON) or diets with 1% NHY or 1% HY. Eight animals were sacrificed 2 wk after weaning for histological investigations in the jejunum and colon, determination of apparent ileal digestibility (AID) of CP and ether extract (EE), and electrophysiological measurements in the jejunal tissue after addition of carbachol or l-glutamine using Ussing chambers. In experiment 1, different treatments had no significant effect on pig performance, but diet HY1 tended to increase ADG and G:F in wk 2 after weaning (P < 0.1). In experiment 2, diet HY1 increased feed intake in wk 2 (P < 0.05), whereas NHY yeast had no effect on feed intake. Villus height, villus/crypt ratio in jejunum (P < 0.05), and crypt depth in colon (P < 0.01) were increased in group HY1. Crypt depth in jejunum and small intestinal length were not affected by different treatments. The AID of CP and EE tended to increase in group HY1 (P < 0.1) compared with groups CON and NHY. In the Ussing chamber experiments, no changes in basal electrophysiological parameters were observed, and the reactions of the treatment groups to carbachol and l-glutamine were comparable. ADFI was positively correlated with different parameters of intestinal morphology (villus height, villus/crypt ratio, crypt depth in colon, length of small intestine), AID of CP, EE, and performance. The results suggest that a supplementation of 1% HY based on K. fragilis to pig diets may positively influence ADFI and intestinal morphology in pig in the early postweaning period (d 1 to 14).

Introduction of a quality management system compliant with DIN EN ISO 9001:2000 into a university department of nuclear medicine

In 1995, the management of the University Clinic Hamburg-Eppendorf proposed to establish a total quality assurance (QA) system. A revised QA-system has been introduced stepwise in the department of nuclear medicine since 1997, and certification was achieved in accordance with DIN EN ISO 9001:2000 on February 14,2001.

The QA-handbook is devided into two parts. The first part contains operational (diagnostic and therapeutic) procedures in so-called standard operating procedures (SOP). They describe the indication of procedures as well as the competences and time necessary in a standardized manner. Up to now, more than 70 SOPs have been written as a collaborative approach between technicians and physicians during daily clinical routine after analysing and discussing the procedures. Thus, the results were more clearly defined processes and more satisfied employees.

The second part consists of general rules and directions concerning the security of work and equipment as well as radialion protection tasks, hygiene etc. as it is required by the law. This part was written predominantly by the management of the department of nuclear-medicine and the QA-coordinator. Detailed information for the patients, documentation of the work-flows as well as the medical report was adapted to the QM-system. Although in the introduction phase of a QA-system a vast amount of time is necessary, some months later a surplus for the clinical workday will become available. The well defined relations of competences and procedures will result in a gain of time, a reduction of costs and a help to ensure the legal demands. Last but not least, the QA-system simply helps to build up confidence and acceptance both by the patients and the referring physicians.

Comparing benthic biogeochemistry at a sandy and a muddy site in the Celtic Sea using a model and observations

Results from a 1D setup of the European Regional Seas Ecosystem Model (ERSEM) biogeochemical model were compared with new observations collected under the UK Shelf Seas Biogeochemistry (SSB) programme to assess model performance and clarify elements of shelf-sea benthic biogeochemistry and carbon cycling. Observations from two contrasting sites (muddy and sandy) in the Celtic Sea in otherwise comparable hydrographic conditions were considered, with the focus on the benthic system. A standard model parameterisation with site-specific light and nutrient adjustments was used, along with modifications to the within-seabed diffusivity to accommodate the modelling of permeable (sandy) sediments. Differences between modelled and observed quantities of organic carbon in the bed were interpreted to suggest that a large part (>90%) of the observed benthic organic carbon is biologically relatively inactive. Evidence on the rate at which this inactive fraction is produced will constitute important information to quantify offshore carbon sequestration. Total oxygen uptake and oxic layer depths were within the range of the measured values. Modelled depth average pore water concentrations of ammonium, phosphate and silicate were typically 5-20% of observed values at the muddy site due to an underestimate of concentrations associated with the deeper sediment layers. Model agreement for these nutrients was better at the sandy site, which had lower pore water concentrations, especially deeper in the sediment. Comparison of pore water nitrate with observations had added uncertainty, as the results from process studies at the sites indicated the dominance of the anammox pathway for nitrogen removal; a pathway that is not included in the model. Macrofaunal biomasses were overestimated, although a model run with increased macrofaunal background mortality rates decreased macrofaunal biomass and improved agreement with observations. The decrease in macrofaunal biomass was compensated by an increase in meiofaunal biomass such that total oxygen demand remained within the observed range. The permeable sediment modification reproduced some of the observed behaviour of oxygen penetration depth at the sandy site. It is suggested that future development in ERSEM benthic modelling should focus on: (1) mixing and degradation rates of benthic organic matter, (2) validation of benthic faunal biomass against large scale spatial datasets, (3) incorporation of anammox in the benthic nitrogen cycle, and (4) further developments to represent permeable sediment processes.

An approach for the identification of exemplar sites for scaling up targeted field observations of benthic biogeochemistry in heterogeneous environments

Continental shelf sediments are globally important for biogeochemical activity. Quantification of shelf-scale stocks and fluxes of carbon and nutrients requires the extrapolation of observations made at limited points in space and time. The procedure for selecting exemplar sites to form the basis of this up-scaling is discussed in relation to a UK-funded research programme investigating biogeochemistry in shelf seas. A three-step selection process is proposed in which (1) a target area representative of UK shelf sediment heterogeneity is selected, (2) the target area is assessed for spatial heterogeneity in sediment and habitat type, bed and water column structure and hydrodynamic forcing, and (3) study sites are selected within this target area encompassing the range of spatial heterogeneity required to address key scientific questions regarding shelf scale biogeochemistry, and minimise confounding variables. This led to the selection of four sites within the Celtic Sea that are significantly different in terms of their sediment, bed structure, and macrofaunal, meiofaunal and microbial community structures and diversity, but have minimal variations in water depth, tidal and wave magnitudes and directions, temperature and salinity. They form the basis of a research cruise programme of observation, sampling and experimentation encompassing the spring bloom cycle. Typical variation in key biogeochemical, sediment, biological and hydrodynamic parameters over a pre to post bloom period are presented, with a discussion of anthropogenic influences in the region. This methodology ensures the best likelihood of site-specific work being useful for up-scaling activities, increasing our understanding of benthic biogeochemistry at the UK-shelf scale.

Benthic pH gradients across a range of shelf sea sediment types linked to sediment characteristics and seasonal variability

This study used microelectrodes to record pH profiles in fresh shelf sea sediment cores collected across a range of different sediment types within the Celtic Sea. Spatial and temporal variability was captured during repeated measurements in 2014 and 2015. Concurrently recorded oxygen microelectrode profiles and other sedimentary parameters provide a detailed context for interpretation of the pH data. Clear differences in profiles were observed between sediment type, location and season. Notably, very steep pH gradients exist within the surface sediments (10-20 mm), where decreases greater than 0.5 pH units were observed. Steep gradients were particularly apparent in fine cohesive sediments, less so in permeable sandier matrices. We hypothesise that the gradients are likely caused by aerobic organic matter respiration close to the sediment-water interface or oxidation of reduced species at the base of the oxic zone (NH4 +, Mn2+, Fe2+, S-). Statistical analysis suggests the variability in the depth of the pH minima is controlled spatially by the oxygen penetration depth, and seasonally by the input and remineralisation of deposited organic phytodetritus. Below the pH minima the observed pH remained consistently low to maximum electrode penetration (ca. 60 mm), indicating an absence of sub-oxic processes generating H+ or balanced removal processes within this layer. Thus, a climatology of sediment surface porewater pH is provided against which to examine biogeochemical processes. This enhances our understanding of benthic pH processes, particularly in the context of human impacts, seabed integrity, and future climate changes, providing vital information for modelling benthic response under future climate scenarios.

Oxygen dynamics in shelf seas sediments incorporating seasonal variability

Shelf sediments play a vital role in global biogeochemical cycling and are particularly important areas of oxygen consumption and carbon mineralisation. Total benthic oxygen uptake, the sum of diffusive and faunal mediated uptake, is a robust proxy to quantify carbon mineralisation. However, oxygen uptake rates are dynamic, due to the diagenetic processes within the sediment, and can be spatially and temporally variable. Four benthic sites in the Celtic Sea, encompassing gradients of cohesive to permeable sediments, were sampled over four cruises to capture seasonal and spatial changes in oxygen dynamics. Total oxygen uptake (TOU) rates were measured through a suite of incubation experiments and oxygen microelectrode profiles were taken across all four benthic sites to provide the oxygen penetration depth and diffusive oxygen uptake (DOU) rates. The difference between TOU and DOU allowed for quantification of the fauna mediated oxygen uptake and diffusive uptake. High resolution measurements showed clear seasonal and spatial trends, with higher oxygen uptake rates measured in cohesive sediments compared to the permeable sediment. The significant differences in oxygen dynamics between the sediment types were consistent between seasons, with increasing oxygen consumption during and after the phytoplankton bloom. Carbon mineralisation in shelf sediments is strongly influenced by sediment type and seasonality.

Bovine milk-based formula leads to early maturation-like morphological, immunological, and functional changes in the jejunum of neonatal piglets

Artificial rearing and formula feeding is coming more into the focus due to increasing litter sizes and limited nursing capacity of sows. The formula composition is important to effectively support the development of the gut and prevent intestinal dysfunction in neonatal piglets. In this study, newborn piglets ( = 8 per group) were fed a bovine milk-based formula (FO), containing skimmed milk and whey as the sole protein and carbohydrate sources, or were suckled by the sow (sow milk [SM]). After 2 wk, tissue from the jejunum was analyzed for structural (i.e., morphometry) and functional (i.e., disaccharidase activity, glucose transport, permeability toward macromolecules, and immune cell presence) changes and concomitant expression of related genes. Formula-fed piglets had more liquid feces ( < 0.05) over the entire experimental period. Although FO contained twice as much lactose (46% on a DM basis) as SM (21%) and no maltose or starch, the lactase activity was lower ( < 0.05) and glucose transport capacity was higher ( < 0.05) in FO-fed pigs. The relative proportion of intraepithelial natural killer cells and proinflammatory cytokine gene expression (, , and ) was higher in FO-fed pigs ( < 0.05). Piglets fed FO had deeper crypts, larger villus area, and higher expression of caspase 3 and proliferating cell nuclear antigen ( < 0.05). Epithelial permeability toward fluorescein isothiocyanate-dextran was higher and expression of claudin-4 was lower in FO-fed piglets ( < 0.05). The data suggest an early response to bovine milk-based compounds in the FO accompanied with early onset of functional maturation and impaired barrier function. Whether lactose, absence of species-specific protective factors, or antigenicity of foreign proteins lead to to the observed intestinal reactions requires further clarification.

Data integration for identification of important transcription factors of STAT6-mediated cell fate decisions

Data integration has become a useful strategy for uncovering new insights into complex biological networks. We studied whether this approach can help to delineate the signal transducer and activator of transcription 6 (STAT6)-mediated transcriptional network driving T helper (Th) 2 cell fate decisions. To this end, we performed an integrative analysis of publicly available RNA-seq data of Stat6-knockout mouse studies together with STAT6 ChIP-seq data and our own gene expression time series data during Th2 cell differentiation. We focused on transcription factors (TFs), cytokines, and cytokine receptors and delineated 59 positively and 41 negatively STAT6-regulated genes, which were used to construct a transcriptional network around STAT6. The network illustrates that important and well-known TFs for Th2 cell differentiation are positively regulated by STAT6 and act either as activators for Th2 cells (e.g., Gata3, Atf3, Satb1, Nfil3, Maf, and Pparg) or as suppressors for other Th cell subpopulations such as Th1 (e.g., Ar), Th17 (e.g., Etv6), or iTreg (e.g., Stat3 and Hif1a) cells. Moreover, our approach reveals 11 TFs (e.g., Atf5, Creb3l2, and Asb2) with unknown functions in Th cell differentiation. This fact together with the observed enrichment of asthma risk genes among those regulated by STAT6 underlines the potential value of the data integration strategy used here. Thus, our results clearly support the opinion that data integration is a useful tool to delineate complex physiological processes.

Influence of fermentable carbohydrates or protein on large intestinal and urinary metabolomic profiles in piglets

It was recently shown that variations in the ratio of dietary fermentable carbohydrates (fCHO) and fermentable protein (fCP) differentially affect large intestinal microbial ecology and the mucosal response. Here we investigated the use of mass spectrometry to profile changes in metabolite composition in colon and urine associated with variation in dietary fCHO and fCP composition and mucosal physiology. Thirty-two weaned piglets were fed 4 diets in a 2 × 2 factorial design with low fCP and low fCHO, low fCP and high fCHO, high fCP and low fCHO, and high fCP and high fCHO. After 21 to 23 d, all pigs were euthanized and colon digesta and urine metabolite profiles were obtained by mass spectrometry. Analysis of mass spectra by partial least squares approach indicated a clustering of both colonic and urinary profiles for each pig by feeding group. Metabolite identification and annotation using the Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathways revealed increased abundance of metabolites associated with arachidonic acid metabolism in colon of pigs fed a high concentration of fCP irrespective of dietary fCHO. Urinary metabolites did not show as clear patterns. Mass spectrometry can effectively differentiate metabolite profiles in colon contents and urine associated with changes in dietary composition. Whether metabolite profiling is an effective tool to identify specific metabolites (biomarkers) or metabolite profiles associated with gut function and integrity needs further elucidation.

Characteristics of neurons and glia in the brain of Fukuyama type congenital muscular dystrophy

Fukuyama type congenital muscular dystrophy accompanies central nervous system and ocular lesions. Morphological findings suggest that major central nervous system lesions, such as cortical dysplasia, are caused by the abnormal glia limitans due to an impairment of astrocytes. Increase of corpora amylacea and neurofibrillary tangles suggests acceleration of the aging process in the Fukuyama type congenital muscular dystrophy brain. Glycosylation of alpha-dystroglycan is decreased in the central nervous system of Fukuyama type congenital muscular dystrophy in a similar manner to the skeletal muscle, but dystroglycan mRNA levels appear to be increased. Glycosylated alpha-dystroglycan is reduced in the glia limitans formed by astrocytic endfeet. Slight accumulation of N(epsilon)-(carboxymethyl)lysine, an oxidative modification product, is observed in astrocytes of Fukuyama type congenital muscular dystrophy and in an astrocytoma cell line with suppressed fukutin expression. Cerebral cortical neurons of Fukuyama type congenital muscular dystrophy and controls react with an antibody for core alpha-dystroglycan but not with an antibody for glycosylated alpha-dystroglycan. Carboxymethyl lysine is accumulated in cortical neurons of a severe case of Fukuyama type congenital muscular dystrophy. Both astrocytes and neurons appear to be sensitive to oxidative stress when fukutin is suppressed. However, it is still unclear how the loss of fukutin causes astrocytic and neuronal dysfunction. Since the central nervous system is composed of several components that are closely related to each other, more investigations are needed for thorough understanding of the Fukuyama type congenital muscular dystrophy brain. Moreover, since astrocytes and epithelial cells may show different cellular responses to fukutin suppression, it seems important to evaluate the functions of fukutin in each type of cell or tissue, not only to prove the pathogenesis of Fukuyama type congenital muscular dystrophy, but also for applying appropriate therapies, especially those at molecular level.

Molecular diversity of the dystrophin-like protein complex in the developing and adult avian retina

Mutations in dystrophin cause muscular dystrophy but also affect the CNS, including information processing in the retina. To better understand the molecular basis of these CNS deficits, we analyzed the molecular composition and developmental appearance of dystrophin and of the dystrophin-associated protein complex (DPC) in the embryonic and adult avian retina. We detected a concentration of the DPC at the vitreal border and in the outer plexiform layer of the adult retina. At both locations the complex had a different molecular composition and different developmental expression pattern. At the vitreal border, the complex was composed of utrophin, alpha-dystrobrevin-1, and dystroglycan, and was present at all stages of retinal development even before neurogenesis and gliogenesis. On the other hand, the complex in the outer plexiform layer consisted of dystrophin, beta-dystrobrevin and dystroglycan. The distribution of this complex changed from a diffusely distributed to an aggregated form during development concomitant with synapse formation in the outer plexiform layer. Solubilization of the retinal extracellular matrix by intravitreal injection of collagenase resulted in a redistribution of the complex at the retinal vitreal border but had no influence on the distribution of the dystrophin-associated proteins in the outer plexiform layer. These results demonstrate two types of dystrophin-like complexes in the chick retina with differential molecular compositions, different anchorage to the extracellular matrix, and different developmental expression patterns, suggesting distinct functions for the DPC at both locations.

[Introduction of a quality management system compliant with DIN EN 9001:2000 in a university department of nuclear medicine]

In 1995, the management of the University Clinic Hamburg-Eppendorf proposed to establish a total quality assurance (QA) system. A revised QA-system has been introduced stepwise in the department of nuclear medicine since 1997, and certification was achieved in accordance with DIN EN ISO 9001:2000 on February 14, 2001. The QA-handbook is divided into two parts. The first part contains operational (diagnostic and therapeutic) procedures in so-called standard operating procedures (SOP). They describe the indication of procedures as well as the competences and time necessary in a standardized manner. Up to now, more than 70 SOPs have been written as a collaborative approach between technicians and physicians during daily clinical routine after analysing and discussing the procedures. Thus, the results were more clearly defined processes and more satisfied employees. The second part consists of general rules and directions concerning the security of work and equipment as well as radiation protection tasks, hygiene etc. as it is required by the law. This part was written predominantly by the management of the department of nuclear-medicine and the QA-coordinator. Detailed information for the patients, documentation of the work-flows as well as the medical report was adopted to the QM-system. Although in the introduction phase of a QA-system a vast amount of time is necessary, some months later a surplus for the clinical workday will become available. The well defined relations of competences and procedures will result in a gain of time, a reduction of costs and a help to ensure the legal demands. Last but not least, the QA-system simply helps to build up confidence and acceptance both by the patients and the referring physicians.

Decreased glomerular expression of agrin in diabetic nephropathy and podocytes, cultured in high glucose medium

AIM

A decrease in glomerular heparan sulfate (HS) proteoglycan (PG), without apparent decrease in HSPG core protein expression, has been reported to occur in diabetic nephropathy (DN). In most studies however, agrin, the major HSPG core protein in the glomerular basement membrane, has not been studied. This prompted us to study the glomerular expression of agrin in parallel to the expression of HS-glycosaminoglycans (GAG) in biopsies of patients with DN. Furthermore, the influence of glucose on agrin production in cultured podocytes and the expression of agrin in fetal kidneys was investigated.

METHODS

Cryostat sections of renal biopsies from patients with DN (n = 8) and healthy controls (HC, n = 8), were stained for agrin and HS-GAG. Sections of fetal kidneys were double stained for agrin and CD35 or CD31. Stainings were performed by indirect immunofluorescence (IIF). The production of agrin by cultured human podocytes was tested by ELISA and IIF.

RESULTS

The expression of agrin, detected by AS46, was significantly reduced in biopsies from patients with DN compared to HC (p < 0.01). Similar findings were observed when monoclonal antibody JM72 was used (p < 0.05). In addition, a significant reduction in the glomerular expression of HS-GAG was detected with JM403 in these patients (p < 0.01). Agrin is expressed in cultured podocytes, the expression hereof was reduced when the cells were cultured in the presence of 25 mM D-glucose (p < 0.01). In biopsies of human fetal kidneys, glomerular expression of agrin coincided with the expression of CD31. In early stages of glomerular differentiation there was a strong staining for agrin and CD31 while CD35 was only slightly positive.

CONCLUSIONS

Our data argue against a selective dysregulation in HSPG sulfation in DN, but suggest a pivotal role for hyperglycemia in the downregulation of agrin core protein production.

An alternative amino-terminus expressed in the central nervous system converts agrin to a type II transmembrane protein

Agrin is a basal lamina-associated heparansulfate proteoglycan that is a key molecule in the formation of the vertebrate neuromuscular junction. The carboxy-terminal part of agrin is involved in its synaptogenic activity. The amino-terminal end of chick agrin consists of a signal sequence, required for the targeting of the protein to the secretory pathway, and the amino-terminal agrin (NtA) domain that binds to basal lamina-associated laminins. The cDNA encoding rat agrin lacks this NtA domain and instead codes for a shorter amino-terminal end. While the NtA domain is conserved in several species, including human, sequences homologous to the amino-terminus of rat agrin have not been described. In this work, we have characterized these amino-terminal sequences in mouse and chick. We show that they all serve as a noncleaved signal anchor that immobilizes the protein in a N(cyto)/C(exo) orientation in the plasma membrane. Like the secreted form, this transmembrane form of agrin is highly glycosylated indicative of a heparansulfate proteoglycan. The structure of the 5' end of the mouse agrin gene suggests that a distinct promoter drives expression of the transmembrane form. Agrin transcripts encoding this form are enriched in the embryonic brain, particularly in neurons. To our knowledge, this is the first example of a molecule that is synthesized both as a basal lamina and a plasma membrane protein.

Dissociation of the dystroglycan complex in caveolin-3-deficient limb girdle muscular dystrophy

Limb girdle muscular dystrophy is a group of clinically and genetically heterogeneous disorders inherited in an autosomal recessive or dominant mode. Caveolin-3, the muscle-specific member of the caveolin gene family, is implicated in the pathogenesis of autosomal dominant limb girdle muscular dystrophy 1C. Here we report on a 4-year-old girl presenting with myalgia and muscle cramps due to a caveolin-3 deficiency in her dystrophic skeletal muscle as a result of a heterozygous 136G-->A substitution in the caveolin-3 gene. The novel sporadic missense mutation in the caveolin signature sequence of the caveolin-3 gene changes an alanine to a threonine (A46T) and prevents the localization of caveolin-3 to the plasma membrane in a dominant negative fashion. Caveolin-3 has been suggested to interact with the dystrophin-glycoprotein complex, which in striated muscle fibers links the cytoskeleton to the extracellular matrix and with neuronal nitric oxide synthase. Similar to dystrophin-deficient Duchenne muscular dystrophy, a secondary decrease in neuronal nitric oxide synthase and alpha-dystroglycan expression was detected in the caveolin-3-deficient patient. These results implicate an important function of the caveolin signature sequence and common mechanisms in the pathogenesis of dystrophin-glycoprotein complex-associated muscular dystrophies with caveolin-3-deficient limb girdle muscular dystrophy.

Distribution of the integrin beta 1 subunit on radial cells in the embryonic and adult avian retina

The distribution of the beta1 integrin subunit was investigated in the developing and adult chick retina at the light and electron microscopic levels, using two different monoclonal antibodies. Western blotting revealed a single band with a molecular weight of approximately 130 kDa in the retina and in a number of other tissues, indicating the specificity of the antibodies. In the retina, immunoreactivity was detected on radial cells spanning the entire width between the pigment epithelium and the vitreal border. These cells were undifferentiated neuroepithelial cells at early stages and radial Müller glial cells at later stages of development. At all stages, the beta1 subunit was concentrated at the vitreal border of the retina around the inner limiting membrane. Mechanical isolation of the inner limiting membrane, as well as immunoelectron microscopy, demonstrated that this immunoreactivity was due to a concentration of the beta1 subunit in the endfeet of neuroepithelial and Müller glial cells. Injection of collagenase into the vitreous of live embryos, a procedure that selectively removes the inner limiting membrane, but does not proteolytically degrade the integrin protein, resulted in a redistribution of the integrin immunoreactivity, demonstrating that the integrity of the basal lamina is required for the maintenance of the concentration of the beta1 subunit in the endfeet. These results suggest a role for the beta1 subunit-containing integrin heterodimers in the adhesion of neuroepithelial and Müller glial cells to extracellular matrix components of the inner limiting membrane, possibly stabilizing the radial morphology of these cells.

FDG PET detection of unknown primary tumors

The management of patients presenting with metastases of unknown primary origin remains a clinical challenge despite a large variety of imaging modalities. The aim of this study was to evaluate FDG PET in detecting the sites of primary cancer in these patients.

METHODS

Fifty-three patients with metastatic cervical adenopathy (n = 44) or extracervical metastases (n = 9) of unknown primary origin were included after extensive but inconclusive conventional diagnostic work-up. Patients received 370 MBq FDG (10 mCi) intravenously, and whole-body images were acquired at 60 min after injection. Clinical, surgical, and histopathologic findings and complete correlative imaging were used to assess the results.

RESULTS

In 27 of 53 patients FDG PET showed focal tracer accumulations corresponding to potential primary tumor sites located in the lungs (n = 12), the palatine tonsil (n = 5), the salivary glands (n = 2), the nasopharynx (n = 1), the oropharynx (n = 3), the maxillary sinus (n = 1), and the larynx (n = 1). Moreover, in 2 patients FDG PET revealed lesions suspected to be tumors in the breast and the ileocolonic area. In 20 (37.8%) of these 53 patients FDG PET was true-positive, identifying the primary tumor in the lungs (n = 10), the head and neck region (n = 8), the breast (n = 1), and the ileocolonic area (n = 1). In 6 of 27 patients FDG PET was false-positive, predominantly identifying suspicious areas in the palatine tonsil (n = 3). One patient denied further diagnostic work-up after PET; thus, positive PET could not be evaluated. In 26 of 53 patients PET did not reveal lesions suspected to be the primary. However, primary tumors were not found in these patients at clinical follow-up.

CONCLUSION

FDG PET is a valuable diagnostic tool in patients with cancer of unknown primary because it imaged unknown primary tumors in about one third of all patients investigated. In addition, FDG PET assists in both guiding biopsies for histologic evaluation and selecting the appropriate treatment protocols for these patients.

Expression of EMAP II in the developing and adult mouse

Endothelial monocyte-activating polypeptide II (EMAP II) is a chemoattractant for monocytes and granulocytes. EMAP II is translated as a precursor protein, proEMAP II, and is proteolytically cleaved to become the mature, biologically active cytokine. In this study we show that the EMAP II mRNA and the EMAP II precursor protein are constitutively expressed by all cell types analyzed in vitro, whereas the mature cytokine is only present in the supernatant of apoptotic cells. During mouse embryogenesis we found widespread expression of the EMAP II mRNA with transcripts being abundant in areas of tissue remodeling, where a large number of apoptotic cells could be detected by TUNEL staining. In the adult mouse, strong expression of the EMAP II mRNA is restricted to the brain, testis and thymus. Interestingly, prominent signals for EMAP II mRNA are found in local correlation with sites of apoptosis in thymus and testis but not in the brain. We propose that during development, the generation and release of the mature EMAP II may provide a mechanism for the recruitment of phagocytic cells to sites of programmed cell death. In the adult brain, the generation of mature EMAP II may contribute to the recruitment of monocytes and the immunosurveillance of this tissue.

The neurobiology of duchenne muscular dystrophy: learning lessons from muscle?

Several forms of inherited muscular dystrophy are associated with brain abnormalities and cognitive impairment. One of the most common and severe of these diseases is Duchenne muscular dystrophy (DMD). Dystrophin, the product of the DMD gene, is found in neurones, where it is associated with the postsynaptic membrane. Cognitive impairment in individuals with DMD is thought to be due to an abnormality in the neuronal membrane that is caused by lack of dystrophin. Recent experimental evidence has provided valuable clues in our understanding of the complex molecular neurobiology of muscular dystrophy.

[Efficacy of radiation synovectomy in degenerative inflammatory and chronic inflammatory joint diseases]

AIM

Effect of radiosynovectomy (RS) should be evaluated both by subjective and objective parameters in patients with osteoarthritis and in patients with inflammatory joint disorders not caused by rheumatoid arthritis.

METHODS

A total of 98 joints in 61 patients were investigated. Patients were divided into two groups. The first group included 35 patients with therapy-resistant effusions caused by severe osteoarthritis (46 joints). The second group consisted of 26 patients (52 joints) with ankylosing spondylitis, reactive arthritis, undifferentiated spondylarthropathy, psoriatic arthritis, pigmented villo-nodular synovitis, and recurrent synovitis following surgery. Effect of RS was evaluated by a standardized questionnaire and quantified by T/B-ratios derived from blood pool images prior to and after RS.

RESULTS

Within the first patient group suffering from osteoarthritis, 40% showed a good or excellent improvement of clinical symptoms, 51% were unchanged, and in 9% symptoms worsened. Similar results were found in the second patient group. The majority of unchanged results were small finger joints. In contrast, wrist and knee joints showed a better improvement. Good correlation between results of bone scan and patients subjective impression was found in 38% and 67% in the first and the second patient group, respectively.

CONCLUSION

Radiosynovectomy might be an effective treatment in osteoarthritis and inflammatory joint disorders not caused by rheumatoid arthritis.

Expression, distribution and ultrastructural localization of the synapse-organizing molecule agrin in the mature avian retina

At the vertebrate neuromuscular junction the extracellular matrix molecule agrin is responsible for the formation, maintenance and regeneration of most if not all postsynaptic specializations. Several agrin isoforms are generated by alternative splicing which differ in their function and which are all expressed in the CNS. To analyse the role of agrin in the CNS, we investigated the expression and ultrastructural localization of agrin in the posthatched chick retina. In situ hybridization revealed the presence of agrin mRNA in all cellular layers of the mature retina, indicating that most if not all major retinal cell types synthesize agrin. Pan-specific as well as isoform-specific antiagrin antisera stained the optic fibre layer and the outer plexiform layer. However, only the pan-specific antiserum additionally stained the inner limiting membrane. Immunoelectron microscopy showed that in the optic fibre layer agrin was associated with ganglion cell axons and that at least part of this agrin corresponds to a neuronal isoform of agrin. In the outer plexiform layer, agrin was localized in the cleft between the photoreceptor terminals and the invaginating horizontal and bipolar cell dendrites. In the synapse-containing inner plexiform layer both antisera revealed punctate immunoreactivity. This staining corresponded to agrin concentrated in the synaptic cleft of conventional synapses as determined by preembedding immunoelectron microscopy. Agrin is thus concentrated at mature interneuronal synapses as it is at the neuromuscular junction, consistent with a role of agrin during formation and/or maintenance of synapses in the CNS.

Radioprotection of salivary glands by amifostine in high-dose radioiodine treatment. Results of a double-blinded, placebo-controlled study in patients with differentiated thyroid cancer

BACKGROUND AND PURPOSE

Parenchymal impairment of salivary glands following high-dose radioiodine treatment is a well-known side effect in general caused by free radicals. Therefore, the radioprotective effect of the radical scavenger amifostine was evaluated prospectively in patients receiving high-dose radioiodine treatment.

PATIENTS AND METHODS

Parenchymal function was assessed by quantitative salivary gland scintigraphy performed in 50 patients with differentiated thyroid cancer prior to and 3 months after high-dose radioiodine treatment with either 3 GBq 131I (n = 21) or 6 GBq 131I (n = 29) in a double-blinded, placebo-controlled study. Twenty-five patients treated with 500 mg/m2 amifostine intravenously prior to high-dose radioiodine treatment were compared to 25 control patients receiving physiological saline solution. Xerostomia was graded according to WHO-criteria.

RESULTS

In 25 control patients high-dose radioiodine treatment significantly (p < 0.001) reduced parenchymal function of parotid and submandibular glands by 40.2 +/- 14.1% and 39.9 +/- 15.3%, respectively. Nine out of these 25 patients developed Grade I and 2 Grade II xerostomia. In contrast, in 25 amifostine-treated patients there was no significant (p = 0.691) decrease in parenchymal function following high-dose radioiodine treatment, and xerostomia did not occur in any of them.

CONCLUSION

Parenchymal damage of salivary glands induced by high-dose radioiodine treatment can be significantly reduced by amifostine which may improve quality of life of patients with differentiated thyroid cancer.

Synapse formation and agrin expression in stratospheroid cultures from embryonic chick retina

Stratospheroids are three-dimensional cellular spheres which develop in vitro through the proliferation and differentiation of retinal neuroepithelial precursor cells. We investigated synapse formation in stratospheroids by analyzing the development of aggregates of synapse-associated molecules and of electron microscopically identifiable synaptic specializations. Our results show that the first aggregates of the GABA(A) receptor, the glycine receptor, and gephyrin appear in the inner plexiform layer after 8 days in culture simultaneously with the development of the first active zones and postsynaptic densities. In contrast, presynaptic molecules including synaptophysin could be detected in the inner plexiform layer before synaptogenesis, suggesting functions for these molecules in addition to neurotransmitter exocytosis at mature synapses. Similar to the retina in vivo, synapses were not found in the nuclear layers of stratospheroids. We also analyzed the isoform pattern, expression, and distribution of the extracellular matrix molecule agrin, a key regulator during formation, maintenance, and regeneration of the neuromuscular junction. In stratospheroids, several agrin isoforms were expressed as highly glycosylated proteins with an apparent molecular weight of approximately 400 kDa, similar to the molecular weight of agrin in the retina in vivo. The expression specifically of the neuronal isoforms of agrin was concurrent with the onset of synaptogenesis. Moreover, the neuronal agrin isoforms were exclusively found in the synapse-containing inner plexiform layer, whereas other agrin isoforms were associated also with the inner limiting membrane and with Müller glial cells. These results show that synapse formation is very similar in stratospheroids and in the retina in vivo, and they suggest an important role for agrin during CNS development.

Salivary gland protection by S-2-(3-aminopropylamino)-ethylphosphorothioic acid (amifostine) in high-dose radioiodine treatment: results obtained in a rabbit animal model and in a double-blind multi-arm trial

Since differentiated thyroid cancer has an excellent prognosis, reduction of long-term side effects of high-dose radioiodine treatment (HD-RIT), i.e. salivary gland impairment is important. Thus, radioprotective effects of amifostine were studied. Salivary gland function was quantified by scintigraphy both in rabbits and patients. Fifteen rabbits were studied prior to and up to 6 months after HD-RIT applying 2 GBq 131I. Ten animals received 200 mg/kg amifostine prior to HD-RIT, and five served as controls. Animals were examined histopathologically. Fifty patients with differentiated thyroid cancer were evaluated prospectively prior to and 3 months after HD-RIT with either 3 or 6 GBq 131I in a double-blind, placebo-controlled study. Twenty-five patients were treated with 500 mg/m2 amifostine intravenously prior to HD-RIT, and 25 patients receiving physiological saline solution served as controls. Complete ablation of the thyroid was achieved in all rabbits four weeks after HD-RIT. In control rabbits 6 months after HD-RIT parenchymal function was reduced significantly (p < 0.0001) by 75.3 +/- 5.3% and 53.6 +/- 17.4% in parotid and submandibular glands, respectively. In contrast, in amifostine-treated rabbits parenchymal function was not significantly reduced. Histopathologically, marked lipomatosis was observed in control animals but was negligible in amifostine-treated animals. In control patients, salivary gland function was significantly (p < 0.001) reduced by 40.2 +/- 14.1% and 39.9 +/- 15.3% in parotid and submandibular glands, respectively, three months after HD-RIT, and 11 patients developed xerostomia. In 25 amifostine-treated patients, salivary gland function was not significantly reduced (p = 0.691), and xerostomia did not occur. Thus, parenchymal damage in salivary glands induced by high-dose radioiodine therapy can be reduced significantly by amifostine. This may improve quality of life of patients with differentiated thyroid cancer.

Pregnancy testing before high-dose radioiodine treatment: a case report

This case emphasizes that negative urine pregnancy testing and a written declaration of the patient are not sufficient to safely exclude an early pregnancy. Serum pregnancy testing inherently has a diagnostic gap of about 1 wk following conception. We recommend sufficient contraception at least 1 mo before radioiodine treatment in women of childbearing age.

Imprinted polymer-based sensor system for herbicides using differential-pulse voltammetry on screen-printed electrodes

A sensor system for the herbicide 2,4-dichlorophenoxy-acetic acid has been developed based on specific recognition of the analyte by a molecularly imprinted polymer and electrochemical detection using disposable screen-printed electrodes. The method involves a competitive binding step with a nonrelated electrochemically active probe. For batch binding assays, imprinted polymer particles are incubated in suspension with the analyte and the probe, followed by centrifugation and quantification of the unbound probe in the supernatant. Two different compounds, namely 2,4-dichlorophenol and homogentisic acid, were tested as potential electroactive probes. Both compounds could be conveniently detected by differential-pulse voltammetry on screen-printed, solvent-resistant three-electrode systems having carbon working electrodes. Whereas 2,4-dichlorophenol showed very high nonspecific binding to the polymer, homogentisic acid bound specifically to the imprinted sites and thus allowed calibration curves for the analyte in the micromolar range to be recorded. An integrated sensor was developed by coating the imprinted polymer particles directly onto the working electrode. Following incubation of the modified electrode in a solution containing the analyte and the probe, the bound fraction of the probe is quantified. This system provides a cheap, disposable sensor for rapid determination of environmentally relevant and other analytes.

Clinical value of 24-hour delayed imaging in somatostatin receptor scintigraphy for meningioma

Somatostatin receptor scintigraphy (SRS) using 111In-octreotide has proven useful in patients suspected of having meningiomas. Delayed imaging is regularly performed up to 24 h postinjection. However, this procedure is time consuming and expensive. Therefore, we investigated whether 24-h imaging may be omitted in these patients.

METHODS

After clinical examination and standard MRI, 71 patients were suspected of having 92 meningioma lesions. Before surgery, all patients underwent SRS after intravenous injection of 200 MBq (5.4 mCi) 111In-octreotide. Planar whole-body images were obtained at 10 min and 1, 4 and 24 h, and SPECT was performed at 4 and 24 h. Results of SRS in all lesions were evaluated with respect to histology and time of image acquisition.

RESULTS

SRS yielded 58 true-positive, 20 true-negative and 14 false-negative results, with the false-negatives all less than 5 mL (2.3+/-2.1 mL) in volume. In 52 of 58 true-positive lesions (89.7%), diagnosis could be established by 4-h imaging without further information by 24-h imaging. In 10 of the 52 lesions, SPECT was necessary to confirm planar findings. Imaging at 24 h was necessary in only 6 of 58 true-positive lesions (10.3%): 3 patients who had intracranial relapse of meningioma (volume < 5 mL) and 3 who had spinal meningioma. Thus, a diagnosis of intracranial meningioma could be established in 52 of 55 lesions (95%) using a 4-h imaging protocol.

CONCLUSION

With a 4-h acquisition protocol that includes SPECT imaging, SRS yields sufficient information in patients suspected of having intracranial meningiomas. Delayed imaging at 24 h is recommended only for patients who have small meningiomas (volume < 5 mL), spinal localizations or negative SRS at 4 h.

[F-18 FDG PET for detection of occult primary tumor in patients with lymphatic metastases of the neck region]

BACKGROUND

The occult primary tumor remains an important diagnostic problem in patients with lymph node metastases despite a large variety of imaging modalities. Therefore, the aim of our study was to evaluate the impact of F-18-FDG-positron-emission-tomography (PET) in these patients.

METHODS

The study group included a total of 28 patients aged 39 to 84 years with cervical lymph node metastases of a histologically confirmed squamous cell carcinoma (n = 24) or an undifferentiated carcinoma (n = 4). All patients received 370 MBq F-18-FDG intravenously, and whole-body images were acquired at 60 min p.i. with an ECAT EXACT 47 (921) (Siemens, CTI). All lesions were evaluated either by histology or by CT/MRI.

RESULTS

In 12 patients PET did not reveal suspected tumorous lesions. In contrast in 16/28 patients PET showed focal tracer accumulations corresponding to potential primary tumor sites located in the lungs (n = 7), in the region of the tonsilla palatina (n = 5), in the submandibular gland (n = 1), in the nasopharynx (n = 1), in the larynx (n = 1), or at the base of the tongue (n = 1). In nine out of these 16 patients, the primary was confirmed in the lungs in 5 patients, in the larynx, at the base of the tongue, in the nasopharynx, and the tonsilla palatina in one patient each, respectively. Moreover, in 6 out of 16 patients, PET was false-positive. One patient refused further evaluation of PET findings.

CONCLUSIONS

In approximately one third of all patients, PET detected the primary tumor site, which significantly influenced further therapeutic procedures. Thus, F-18-FDG-PET may be a valuable diagnostic tool in the detection of the primary tumor in patients with cervical lymph node metastases.

Dystrophin and beta-dystroglycan in photoreceptor terminals from normal and mdx3Cv mouse retinae

Mutations in the dystrophin gene cause muscular dystrophy as well as cognitive impairments, including an abnormal dark-adapted electroretinogram. To investigate the basis for the ocular phenotype, we analysed dystrophin and the dystrophin-associated protein beta-dystroglycan in retinae from mdx3Cv mice. This strain has a mutation in the dystrophin gene and abnormalities in the electroretinogram which are similar to those of muscular dystrophy patients. Despite an overall reduction of all dystrophin isoforms and of beta-dystroglycan in retinal tissue from mutant mice, we observed no apparent change in the histotypic layering of the retina, or in the ultrastructure of several specific cell types, including rods and cones. In retinae from wild type and mdx3Cv mice, dystrophin and beta-dystroglycan were concentrated in small extensions of rod and cone photoreceptor terminals protruding into the outer plexiform layer. Beta-dystroglycan but not dystrophin was also clustered around the inner limiting membrane and the capillary basal laminae. While the labelling pattern around the basal laminae was not altered in the mutant mice, we found that the area as well as the intensity of the dystrophin and beta-dystroglycan immunoreactivity associated with the terminals of rod photoreceptors were severely reduced. The same parameters were much less affected in cone terminals. These results show, that dystrophin and beta-dystroglycan are differentially distributed in the retina, and that a severe reduction of dystrophin has no gross effect on retinal structure, but could influence intraretinal signalling at the level of the photoreceptor terminals. Moreover, the mutation in mdx3Cv mice has a selective effect on rods, providing an explanation for the altered electroretinogram.

Lymphoscintigraphy in tumors of the head and neck using double tracer technique

Knowledge of possible lymphatic drainage may facilitate planning of surgery for patients with head and neck tumors. Therefore, the aim of this study was to present a method of lymphoscintigraphy with special attention to an accurate correlation of lymphatic drainage to anatomic regions.

METHODS

Lymphoscintigraphy was performed using a double tracer technique before surgery in a total of 75 patients with squamous cell carcinoma of the head and neck. All patients received 100 MBq 99mTc-colloid at three to four peritumoral sites. A perchlorate solution (2 mL) was given orally to block salivary glands and the thyroid gland. Patients received 50 MBq 99mTc-pertechnetate intravenously for body contouring 20 min postinjection. Planar images were obtained over 5 min each, at 30 min and 4 h postinjection from anterior, right lateral and left lateral views with a large-field-of-view gamma camera. Lymphatic drainage was assessed by visual inspection and assigned to six cervical compartments.

RESULTS

Neither the salivary glands nor the thyroid gland were seen in any of the patients. In 22 of 75 patients (29.3%), the injection site was the only focal tracer uptake seen. In contrast, lymphatic drainage was identified in the remaining 53 patients (70.7%), and lymph nodes could be assigned easily to the six cervical compartments. Of 75 patients, 36 (48%) exhibited ipsilateral lymphatic drainage. In addition, 17 patients (22.7%) with unilateral tumor showed bilateral (n = 12), contralateral (n = 2) or retropharyngeal (n = 3) lymphatic drainage. In 3 of these 17 patients, bilateral lymph node metastases were proven. A subgroup of 12 patients (16%) exhibited N2c nodal status, despite a unilateral localized primary tumor. In 3 of these 12 patients, surgery was extended as a result of scintigraphic findings from unilateral toward bilateral neck dissection, and histology confirmed nodal involvement in these patients.

CONCLUSION

Lymphoscintigraphy using the double tracer technique allows an accurate correlation of lymphatic drainage to the six cervical compartments. This may provide the basis for a re-evaluation of its impact in treatment planning of patients with head and neck tumors.

Quantitative salivary gland scintigraphy

OBJECTIVE

Uptake of 99mTc-pertechnetate in salivary glands reflects intact salivary gland parenchyma. However, no standardized protocol for an accurate quantification of parenchymal function has been established so far.

METHODS

In this paper we report on a validated acquisition protocol supplying a normal database for standardized quantitative salivary gland scintigraphy.

RESULTS

The major advantage of salivary gland scintigraphy, as compared to other imaging modalities, is that both parenchymal function and excretion fraction of all four major salivary glands (i.e., parotid and submandibular glands) can be simultaneously quantified with a single intravenous injection.

CONCLUSION

Quantitative salivary gland scintigraphy is demonstrated to be a suitable imaging modality for research applications in evaluating the effects of radioprotective drugs on salivary glands. Salivary gland scintigraphy is easy to perform, reproducible and well-tolerated by the patient.

Immunosensor for 2,4-dichlorophenoxyacetic acid in aqueous/organic solvent soil extracts

The development of a simple electrochemical immunoassay procedure for the field-based quantification of the herbicide 2,4-D in methanolic soil extracts is presented. The sensor utilizes a competitive immunoassay format incorporating an immobilized antigen complex at the surface of a disposable screen-printed working electrode element. The extent of glucose oxidase-labeled antibody binding to the antigen--electrode is determined amperometrically and is related to sample analyte concentration. The performance of the sensor is assessed in buffer, 30% methanol, and methanolic soil extracts. The device is capable of quantifying 2,4-D in all three matrixes at the low ppm level with coefficient of variation values of 6.2-33.6%. The causes of the variation observed in the sensor response in different soil matrixes are examined and improvements proposed. The sensor, tested in parallel with a commercial 2,4-D immunoassay test kit, yields comparable quantitative data and detection limits while exhibiting greater assay simplicity.

Somatostatin receptor scintigraphy in postsurgical follow-up examinations of meningioma

Surgery is the treatment of choice in patients with meningioma. However, the risk of postoperative, local recurrence is well-known since total resection is not always feasible. Moreover, in these patients MRI may fail to differentiate between tumor remnants, recurrent meningioma or nonspecific hyperperfusion. In this study, the value of functional imaging using somatostatin receptor scintigraphy (SRS) was evaluated in postsurgical follow-up.

METHODS

Before and 2-3 mo after surgery, 27 patients with meningioma received MRI as well as SRS after intravenous injection of 200 MBq 111In-octreotide. Planar whole-body images were obtained at 10 min, 1, 4 and 24 hr postinjection, and SPECT was performed at 4 and 24 hr postinjection. The final diagnosis was proven histologically in all patients.

RESULTS

Before surgery, MRI showed focal contrast enhancement in all patients, and SRS revealed focal accumulation of 111In-octreotide. Thus, MRI and SRS yielded comparable results in all 27 patients. After surgery, MRI showed diffuse contrast enhancement in the area of the primary tumor site in all patients. Thus, MRI did not allow a differentiation between tumor and nonspecific hyperperfusion. In contrast, SRS revealed focal accumulation of 111In-octreotide in 16 of 27 patients indicating remaining tumor tissue or relapse of meningioma. This resulted either in an operative revision or in more frequent postsurgical follow-up examinations. In 11 of 27 patients, SRS was negative. Thus, total resection of meningioma was assumed, and no further interventions were performed.

CONCLUSION

Functional imaging using SRS is a highly specific imaging modality and has a significant impact in postsurgical follow-up in patients with meningioma.

Differential distribution of agrin isoforms in the developing and adult avian retina

At the developing and regenerating neuromuscular junction, agrin is responsible for the formation of aggregates containing the acetylcholine receptor (AChR) and other molecules. Multiple isoforms of agrin are generated by alternative splicing, and the presence of an 8, 11, or 19 (8 + 11) amino acid insert at splice site B is required for agrin's AChR aggregation activity. An antiserum was generated against the 19 amino acid peptide which reacted specifically with the B11 and B19 agrin isoforms. The antiserum blocked the formation of agrin-induced AChR aggregates on myotubes, but the peptide itself had no aggregation activity, suggesting that agrin's active site is close to the splice site, but not the peptide itself. In the embryonic and adult retina anti-peptide immunoreactivity was concentrated in the synapse-containing layers. In contrast, the inner limiting membrane and radial cells, which express strong immunoreactivity with a pan-specific anti-agrin antiserum, were not stained by the anti-peptide antiserum, showing that agrin isoforms are differentially distributed in the retina. In addition, agrin B11 and B19 isoforms were associated with ganglion cell axons, particular at early developmental stages before synapse formation, indicating additional functions for these isoforms in the developing CNS.

Differential distribution of beta-dystroglycan in rabbit and rat retina

The distribution of the dystrophin-associated glycoprotein complex was investigated in rabbit and rat retina by using the monoclonal antibody 43DAG/8D5, which specifically recognizes beta-dystroglycan, a central component of the complex. In cryostat sections of retinae from both species, the authors observed staining of blood vessels, continuous labeling around the vitreal border, and strong immunoreactivity in the outer plexiform layer (OPL). Electron microscopy showed that the immunoreactivity associated with the vitreal border of the retina was the result of a subcellular concentration of beta-dystroglycan in the endfeet of Müller glial cells. A similar concentration was observed in endfeet of perivascular astrocytes in the region of contact with the capillary basal lamina. In the OPL, beta-dystroglycan was associated with the terminals of both rods and cones. The label was almost exclusively found outside the synaptic area and was particularly strong in the extensions of the photoreceptor terminals protruding into the OPL. In the OPL of the rabbit retina, the authors found additional immunoreactivity associated with the tips of postsynaptic horizontal and bipolar cell processes. These results show that the dystrophin-associated glycoprotein complex is subcellularly concentrated in photoreceptor terminals and glial cell endfeet, and that the rabbit retina differs from the rat retina by the additional expression of this complex in bipolar and horizontal cells.

Subcellular concentration of beta-dystroglycan in photoreceptors and glial cells of the chick retina

Mutations in the dystrophin-glycoprotein complex cause muscle degeneration and dysfunctions in the central nervous system, including an impaired synaptic transmission in the outer plexiform layer (OPL) of the retina. To investigate the basis for this ocular phenotype, we analyzed the distribution of beta-dystroglycan, a central member of the dystrophin-glycoprotein complex, in the chick retina by using the 43DAG/8D5 monoclonal antibody. This antibody reacted specifically with chick beta-dystroglycan, as indicated by its staining of the neuromuscular junction, and its reactivity with a single 43-kilodalton band in Western blots. In the retina, beta-dystroglycan was highly concentrated in the OPL and at the vitreal border of the retina, around the inner limiting membrane. Mechanically isolated and flat-mounted inner limiting membranes were stained by the anti-beta-dystroglycan antibody, and this immunoreactivity could be extracted by detergent, indicating that beta-dystroglycan is associated with membranous structures bound to the basal lamina. Consistently, electron microscopy showed a concentration of beta-dystroglycan in the endfeet of Müller glial cells exclusively in the region of direct contact to the inner limiting membrane. In the OPL, beta-dystroglycan immunoreactivity was concentrated in the distal extensions of rod and cone terminals protruding into the outer plexiform layer. There, beta-dystroglycan codistributed with the alpha1beta subunit of the N-type voltage-gated calcium channel. By contrast to previous reports, we did not detect beta-dystroglycan directly associated with the synaptic regions of conventional or ribbon synapses of the retina. These results show that in the retina beta-dystroglycan is exclusively expressed by photoreceptors and glial cells and that beta-dystroglycan is highly concentrated in subcellular regions of glial cell endfeet and photoreceptor terminals. Moreover, the colocalization of beta-dystroglycan with N-type calcium channels in the outer plexiform layer indicates that both proteins might be part of a macromolecular complex.