Cardiac muscle activation; the role of length dependent activation and the novel myosin activator danicamtiv

 

B: Alterations in the length dependent activation (LDA) of left ventricular (LV) muscle fibres, the mechanistic driver of the Frank-Starling Law of the heart, are thought to mediate impaired LV function in heart failure (HF). However, little is known about LDA's role in the left atria (LA). Given the concomitant presence of LA dysfunction in HF, the purpose of this study was to compare/assess LDA on LA and LV muscle, as well to evaluate the effects of a novel small-molecule acto-myosin activator, danicamtiv (formerly known as MYK-491).

M: LA and LV myofibrils from healthy Yucatan mini-pigs were used to determine biomechanical function with ATPase assays, with and without danicamtiv. Skinned LA and LV muscle fibres from these same animals were prepared to study contractile force, Ca2+ sensitivity, active/passive stiffness, and responsiveness to increasing sarcomere length (2.0 and 2.3). These parameters were also evaluated in the presence of danicamtiv.

R: LA myofibrils had significantly faster ATPase and Pi release rates compared to LV, consistent with their respective alpha/beta myosin-isoform content. Despite increased metabolic rate, LA fibres generated less maximum isometric tension (12.3±1.96 vs 35.2±3.07 mN/mm2) and had a lower pCa50 than LV fibres (5.66±0.02 vs 5.82±0.02), demonstrating reduced force-generating capability and Ca2+ sensitivity. Stretch of LV fibres resulted in a gain in tension over a range of pCas (pCa6.4, 6.2, 6.0, and 5.8, all p<0.05). However, in LA, LDA-induced gain was not significant at submaximal pCas (pCa6.4, 6.2, 6.0, all p>0.05). Stretch had no effect on active stiffness, but increased passive stiffness in both muscle types. Stretched LA fibres showed grater passive stiffness compared to LV (196.7±21.5 vs. 138.5±22.3 kN/m3). A stiffer myofilament would in part explain the blunted ability of the LA to generate force in response to stretch. Danicamtiv activated both LA and LV myofibrils, increasing ATPase and Pi release rates, and increased Ca2+ sensitivity in fibres (ΔpCa; LV, 0.320±0.032; LA, 0.149±0.028, p<0.01). Unlike with stretch, danicamtiv had no effect on passive stiffness, yet altered the active stiffness/tension (S/T) relationship in both fiber types, but, differentially. In LV, danicamtiv increased the number of available heads (Y0; 129.9±26.3 vs 10.1±4.2 kN/m3, p<0.001) with no significant effect on slope. In the LA, Y0 was largely unchanged with a significant increase in the slope of the S/T relationship (slope: 34.0±2.9 vs. 20.0±1.9 au, p<0.01). Together, these data suggest an increased number of force producing cross-bridges, without altering passive stiffness.

C: These data confirm the functional differences between LA and LV muscle fibres and demonstrate a blunted ability of LA tissue to recruit force when stretched. The acto-myosin activator danicamtiv increased biochemical activity, Ca2+ sensitivity, and the active S/T relationship in LA and LV fibres without altering passive strain.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): MyoKardia Inc.

Reducing Mcl-1 gene dosage induces dopaminergic neuronal loss and motor impairments in Park2 knockout mice

Mutations in the PARK2 gene are associated with early onset Parkinsonism. The Park2 -/- mouse, however, does not exhibit neurodegeneration or other Parkinson's disease (PD) phenotypes. Previously, we discovered that translation of Mcl-1, a pro-survival factor, is upregulated in the Park2 -/- mouse, suggesting a compensatory mechanism during development. Here we generated the Park2 -/- Mcl-1 +/- mouse and show that by reducing Mcl-1 gene dosage by 50%, the Park2 -/- genotype is sensitized, conferring both dopaminergic neuron loss and motor impairments. We propose that this murine model could be a useful tool for dissecting PD etiology and developing treatment strategies against this neurodegenerative disease.

A recurrent nova super-remnant in the Andromeda galaxy

The accretion of hydrogen onto a white dwarf star ignites a classical nova eruption^1,2-a thermonuclear runaway in the accumulated envelope of gas, leading to luminosities up to a million times that of the Sun and a high-velocity mass ejection that produces a remnant shell (mainly consisting of insterstellar medium). Close to the upper mass limit of a white dwarf³ (1.4 solar masses), rapid accretion of hydrogen (about 10^-7 solar masses per year) from a stellar companion leads to frequent eruptions on timescales of years^4,5 to decades⁶. Such binary systems are known as recurrent novae. The ejecta of recurrent novae, initially moving at velocities of up to 10,000 kilometres per second⁷, must 'sweep up' the surrounding interstellar medium, creating cavities in space around the nova binary. No remnant larger than one parsec across from any single classical or recurrent nova eruption is known^8-10, but thousands of successive recurrent nova eruptions should be capable of generating shells hundreds of parsecs across. Here we report that the most frequently recurring nova, M31N 2008-12a in the Andromeda galaxy (Messier 31 or NGC 224), which erupts annually¹¹, is indeed surrounded by such a super-remnant with a projected size of at least 134 by 90 parsecs. Larger than almost all known remnants of even supernova explosions¹², the existence of this shell demonstrates that the nova M31N 2008-12a has erupted with high frequency for millions of years.

The leakage of sewer systems and the impact on the 'black and odorous water bodies' and WWTPs in China

China has achieved significant progress on wastewater treatment and aquatic environmental protection. However, leakage (in- and exfiltration) of sewer systems is still an issue. By using the statistical data of water and wastewater in 2016 in China, and the person loads (PLs) of water and wastewater in Singapore, the leakage fractions of hydraulic flow, organic carbon (COD), nitrogen (N) and phosphorus (P) mass loading, and in-sewer COD biological removal in the sewer systems of China (except Hong Kong, Macau and Taiwan), Shanghai, Guangzhou and Beijing were reported for the first time. The fractions of hydraulic flow infiltration (13%, Shanghai and Guangzhou) and exfiltration (39%, China) were calculated. Except Beijing, whose sewer networks are under appropriate management with small leakage fractions, the exfiltration fractions of COD (including in-sewer biological COD removal) ranged from 41% (Shanghai) to 66% (China) and averaged 55%; N ranged from 18% (Shanghai) to 48% (China) and averaged 33%; and P ranged from 23% (Shanghai and Guangzhou) to 44% (China) and averaged 30%. The exfiltrated sewage, COD, N and P not only wastes resources, but also contaminates the aquatic environment (especially groundwater) and contributes to 'black and odorous water bodies'. In- and exfiltration in the sewer network leads to low influent COD concentration, C/N ratio and high inorganic solids and inert particulate COD concentrations of many municipal wastewater treatment plants (WWTPs) causing high cost for nutrient removal, poor resource recovery, additional reactor/settler volume requirement and other operational problems. Therefore, tackling sewer leakage is of primary importance to today's environment in China. Recommendations for the inspection of sewer systems and the rehabilitation of damaged sewers as well as the development of design and operation guidelines of municipal WWTPs tailored to the specific local sewage characteristics and other conditions are proposed.

99mTc-MIBI zur Rezidiv- und Metastasensuche bei differenzierten Schilddrüsenkarzinomen

Ziel: Bestimmung der diagnostischen Wertigkeit der MIBI-Szintigraphie bei Lokalrezidiven oder Metastasen von differenzierten Schilddrüsenkarzinomen nach totaler Thyreoidektomie und ablativer Radiojodtherapie. Methoden: Eine Indikation zur Szintigraphie bestand bei 85 Patienten aufgrund von ansteigenden Thyreoglobulinspiegeln oder sonographischem Rezidivverdacht. Die Befunde wurden zytologisch, histologisch oder durch Sonographie, CT und konventionelles Röntgen sowie mit der 131I-Szintigraphie verifiziert. Ergebnisse: Die MIBI-Szintigraphie war bei 32 von 40 Metastasen positiv (80%). Neunzehn Metastasen konnten mittels 131l dargestellt werden. Am effektivsten konnten Lokalrezidive nachgewiesen werden (94%). Hinsichtlich der Spezifiät gab es keine Unterschiede zwischen MIBI und 131 Jod (100%). Eine Differenzierung zwischen entzündlich veränderten Lymphknoten und einem Tumorbefall war möglich. Schlußfolgerung: Die MIBI-Szintigraphie kann empfohlen werden bei V. a. Lokalrezidiv und negativem Radiojodszintigramm. Es ist vorteilhaft, daß die MIBI-Szintigraphie unter Beibehaltung der Levothyr-oxinmedikation durchgeführt werden kann.

Semiquantitative 99mTc-HMPAO-SPECT bei Demenz vom Alzheimer-Typ: Auswirkungen der Wahl von Rekonstruktionsfilter und Referenzregion

Ziel der Studie war es, zu klären, ob die Wahl der Referenzregion und/oder des Rekonstruktionsfilters einen Einfluß auf das Ergebnis der semiquantitativen Analyse einer zur Diagnose der Demenz vom Alzheimer-Typ (DAT) durchgeführten 99mTc-HMPAO-SPECT ausübt. Methoden: Untersucht wurden 19 DAT-Patienten gemäß der Kriterien des NINCDS-ADRDA sowie des DSM-III-R und eine Vergleichsgruppe (n = 14) mit normaler zerebraler Perfusion. Es wurden drei Referenzregionen (Zerebellum, Gesamtschicht, Okzipitalregion) und vier Rekonstruktionsfilter (Hanning fc = 0,7 und 1,0 Nyquist; Butterworth (n = 8) mit fc = 0,5 und 0,9 Nyquist) auf jeweils 12 standardisierte ROI (pro Patient) angewendet. Die Datenauswertung erfolgte mit Hilfe einer ROC-Analyse. Ergebnisse: Es zeigte sich eine Abhängigkeit der bei DAT als charakteristisch beschriebenen bilateralen parieto-temporalen Perfusionsreduktion von den verwendeten Filtern und Referenzregionen. Ein Butterworth-Filter (n = 8; fc = 0,5) kombiniert mit dem Zerebellum als Referenzregion ermöglichte die sicherste Trennung beider Patientengruppen. Schlußfolgerung: Die Wahl der Referenzregion und des Rekonstruktionsfilters hat einen großen Einfluß auf die Ergebnisse einer Semiquantifizierung. Es bedarf daher einer Standardisierung in Abhängigkeit von der jeweiligen Fragestellung.

Diagnostic Evaluation of the Breast Using PET: Optimization of Data Acquisition and Postprocessing

Purpose: Development and evaluation of an optimized protocol for PET examinations of the female breast with 2-F-l8-fluoro-2-deoxyglucose (F-18-FDG). Methods: All PET measurements were performed with a whole-body PET system (ECAT EXACT HR+). In order to examine the women with the breasts freely pendant, a special extension for the patient table made of carbon layer composite was designed. After data acquisition in the 3D modus, emission data were sorted into 2D sinograms using the Fourier rebinning algorithm and reconstructed by means of an ultra-fast iterative 2D algorithm (HOSP). The reconstructed emission scans were superimposed onto the corresponding transmission images. The protocol presented was evaluated in examinations on 6 women with breast lesions after the administration of 150-220 MBq F-l8-FDG. From two adjacent bed positions, emission and transmission data were acquired over periods of 20 min and 10 min, respectively. For comparison, dynamic magnetic resonance (MR) image series were acquired with a whole-body MR system (MAGNET0M SP 4000) using a double-breast coil. Results and Conclusion: Using the designed extension of the patient table, it was possible to examine corpulent women despite the limited patient port of the PET system in the prone position with the breasts freely pendant. Alongside a reduction in motion artifacts, this positioning also offers the possibility of making a direct comparison between PET and MR images. Despite the fact that the amount of F-l8-FDG applied to the patient was markedly reduced, the combination of 3D data acquisition and iterative image reconstruction resulted in excellent quality of the emission scans. By superpositioning of iteratively reconstructed emission and transmission scans, anatomical localization of breast lesions visualized on the emission scans could be improved. The postprocessing of the PET data described was completed in 60 min, this meaning that the presented concept can readily be employed in clinical practice.

High resolution reconstruction of PET images using the iterative OSEM algorithm

Aim: Improvement of the spatial resolution in positron emission tomography (PET) by incorporation of the image-forming characteristics of the scanner into the process of iterative image reconstruction.

Methods: All measurements were performed at the whole-body PET system ECAT EXACT HR+ in 3D mode. The acquired 3D sinograms were sorted into 2D sinograms by means of the Fourier rebinning (FORE) algorithm, which allows the usage of 2D algorithms for image reconstruction. The scanner characteristics were described by a spatially variant line-spread function (LSF), which was determined from activated copper-64 line sources. This information was used to model the physical degradation processes in PET measurements during the course of 2D image reconstruction with the iterative OSEM algorithm. To assess the performance of the high-resolution OSEM algorithm, phantom measurements performed at a cylinder phantom, the hotspot Jaszczack phantom, and the 3D Hoffmann brain phantom as well as different patient examinations were analyzed. Results: Scanner characteristics could be described by a Gaussian-shaped LSF with a full-width at half-maximum increasing from 4.8 mm at the center to 5.5 mm at a radial distance of 10.5 cm. Incorporation of the LSF into the iteration formula resulted in a markedly improved resolution of 3.0 and 3.5 mm, respectively. The evaluation of phantom and patient studies showed that the high-resolution OSEM algorithm not only lead to a better contrast resolution in the reconstructed activity distributions but also to an improved accuracy in the quantification of activity concentrations in small structures without leading to an amplification of image noise or even the occurrence of image artifacts. Conclusion: The spatial and contrast resolution of PET scans can markedly be improved by the presented image restauration algorithm, which is of special interest for the examination of both patients with brain disorders and small animals.

Comparison of diagnostic accuracy of 18F-FDG PET, 123I-IMT- and 99mTc-MIBI SPECT

Aim was to evaluates the diagnostic accuracy of the SPECTtracers 3-123I-α-methyl-L-tyrosine (IMT) and 99mTc(I)- hexakis(2-methoxyisobutylisonitrile) (MIBI) as well as the PET-tracer 2-18F-2-deoxyglucose (FDG) for detecting tumour progression in irradiated low grade astrocytomas (LGA). Patients, methods: We examined 91 patients (56 males; 35 females; 44.7 ± 11.5 years), initially suffering from histologically proven LGAs (mean WHO grade II) and treated by stereotactic radiotherapy (59.0 ± 4.6 Gy). On average 21.9 ± 11.2 months after radiotherapy, patients presented new Gd-DTPA enhancing lesions on MRI, which did not allow a differentiation between progressive tumour (PT) and non-PT (nPT) at this point of time. PET scans (n=82) were acquired 45 min after injection of 208 ± 32 MBq FDG. SPECT scans started 10 min after injection of 269 ± 73 MBq IMT (n=68) and 15 min after injection of 706 ± 63 MBq MIBI (n=34). Lesions were classified as PT and nPT based on prospective follow-up (clinically, MRI) for 17.2 ± 9.9 months after PET/SPECT. Lesion-to-normal ratios (L/N) were calculated using contra lateraly mirrored reference regions for the SPECT examinations and reference regions in the contra lateral grey (GM) and white matter (WM) for FDG PET. Ratios were evaluated by Receiver Operating Characteristic (ROC) analysis. Results: In the patient groups nPT and PT, L/N ratios for FDG (GS) were 0.6 ± 0.3 vs. 1.2 ± 0.5 (p = 0.003), for FDG (WS) 1.2 ± 0.4 vs. 2.6 ± 0.4 (p <0.001), for IMT 1.1 ± 0.1 vs. 1.8 ± 0.4 (p <0.001) and for MIBI 1.6 ± 0.7 vs. 2.6 ± 2.2 (p = 0.554). Areas under the non-parametric ROC-curves were: 0.738 ± 0.059 for FDG (GS), 0.790 ± 0.057 for FDG (WS), 0.937 ± 0.037 for IMT and 0.564 ± 0.105 for MIBI. Conclusion: MIBI-SPECT examinations resulted in a low accuracy and especially in a poor sensitivity even at modest specificity values. A satisfying diagnostic accuracy was reached with FDG PET. Using WM as reference region for FDG PET, a slightly higher AUC as compared to GM was calculated. IMT yielded the best ROC characteristics and the highest diagnostic accuracy for differentiating between PT and nPT in irradiated LGA.

Profile of diabetes in men aged 79-97 years: the Western Australian Health in Men Study

AIMS

To investigate behavioural, physical and biochemical characteristics associated with diabetes in the oldest age group of elderly men.

METHODS

We conducted a cross-sectional analysis of community-dwelling men aged 79-97 years from Perth, Western Australia. Lifestyle behaviours, self-rated health, physical function, and fasting glucose and HbA_1c levels were assessed.

RESULTS

Of 1426 men, 315 had diabetes (22%). Men with diabetes were of similar age to men without (84.9 vs 84.5 years; P = 0.14). Only 26.5% of men with diabetes self-rated their health as excellent or very good, compared with 40.6% of men without diabetes (P < 0.001). Diabetes was associated with less involvement with recreational walking (32.7 vs 41.0%; P < 0.01) and leisure activities (19.0 vs 26.5%; P < 0.01). Men with diabetes had poorer physical function on multiple measures, including longer times for the Timed Up-and-Go test (15.0 ± 6.9 s vs 13.4 ± 5.3 s; P < 0.001) and weaker knee extension (20.2 vs 21.9 kg; P < 0.001). In multivariate analyses, diabetes was associated with an increased prevalence of myocardial infarction (odds ratio 1.80, 95% CI 1.25-2.60; P < 0.001) and falls resulting in injury (odds ratio 1.55, 95% CI 1.06-2.26; P = 0.02). Average HbA_1c was 49 ± 8 mmol/mol (6.6 ± 0.8%) in men with diabetes, with 90.6% of these men on diet or oral hypoglycaemic therapy.

CONCLUSIONS

In older men, diabetes is associated with poorer self-perceived health, reduced healthy lifestyle behaviours and physical function, heart disease and injurious falls. The majority of these men with diabetes had good glycaemic control. Encouraging healthy lifestyle behaviours and improving physical function should be evaluated as interventions to improve quality-of-life and health outcomes.

Surgical management of pituitary metastases

BACKGROUND

Pituitary metastases are rare and commonly described in case reports or small case series. Due to its rarity this entity is not subject to standardized treatment guidelines, there is debate about typical initial symptoms that may lead to finding the correct diagnosis and information about the clinical course is also sparse.

METHODS

We have conducted a retrospective analysis of patients with pituitary metastases who were surgically treated via a transsphenoidal procedure at our institution between 2006 and 2014. Underlying primary disease, clinical and surgical course as well as adjuvant radiotherapy and follow-up data are presented.

RESULTS

14 patients met the inclusion criteria (8 female, 6 male). Mean age was 61.5 years. Most patients became symptomatic with visual symptoms--both visual deterioration and/or diplopia (n = 13)--and anterior lobe insufficiency (n = 8). Surprisingly diabetes insipidus was only seen in three patients. All patients underwent transsphenoidal surgery initially, four patients had to undergo surgery for residual tumor or recurrence, two of them via a transcranial route. Breast cancer was the most common entity (n = 6), followed by prostate cancer (n = 3), nsclc (n = 2) and melanoma, thyroid cancer and renal cancer in one case each. Postoperative MRI showed gross total resection in four cases and residual disease in eight cases (subtotal resection, partial resection and biopsy), two patients files were incomplete regarding MRI-results. All patients underwent adjuvant radiotherapy. Survival after the initial diagnosis of cancer was 36 and 16 months after diagnosis of pituitary metastases.

CONCLUSION

Our results indicate that transsphenoidal surgery is a safe method to resect pituitary metastases and that the extend of resection does not have an influence on survival time. Our results also indicate that diabetes insipidus may not be the most common initial symptom of pituitary metastases and lack thereof should not lead to making a wrong diagnosis and delaying appropriate therapy.

Reduced spermatogonial proliferation and decreased fertility in mice overexpressing cyclin E in spermatogonia

Cyclin E is a key component of the cell cycle regulatory machinery, contributing to the activation of Cdk2 and the control of cell cycle progression at several stages. Cyclin E expression is tightly regulated, by periodic transcription and ubiquitin-mediated degradation. Overexpression of cyclin E has been associated with tumor development and poor prognosis in several tumor types, including germ cell tumors and both cyclin E and its partner Cdk2 are required for normal spermatogenesis. Here we have generated and characterized transgenic mice overexpressing a cyclin E mutant protein, resistant to ubiquitin-mediated proteolysis, in testicular germ cells, under the control of the human EF-1alpha promoter. The transgenic mice develop normally and live a normal life span, with no signs of testicular tumor development. The transgenic mice display however reduced fertility and testicular atrophy, due to reduced spermatogonial proliferation as a consequence of deregulated cyclin E levels. Overall our results show that deregulation of cyclin E expression contribute to infertility, due to inability of the spermatogonial cells to start the mitotic cycles prior to entering meiosis.

Phosphorylation of Mcm2 by Cdc7 promotes pre-replication complex assembly during cell-cycle re-entry

Cyclin E has been shown to have a role in pre-replication complex (Pre-RC) assembly in cells re-entering the cell cycle from quiescence. The assembly of the pre-RC, which involves the loading of six MCM subunits (Mcm2-7), is a prerequisite for DNA replication. We found that cyclin E, through activation of Cdk2, promotes Mcm2 loading onto chromatin. This function is mediated in part by promoting the accumulation of Cdc7 messenger RNA and protein, which then phosphorylates Mcm2. Consistent with this, a phosphomimetic mutant of Mcm2 can bypass the requirement for Cdc7 in terms of Mcm2 loading. Furthermore, ectopic expression of both Cdc6 and Cdc7 can rescue the MCM loading defect associated with expression of dominant-negative Cdk2. These results are consistent with a role for cyclin E-Cdk2 in promoting the accumulation of Cdc6 and Cdc7, which is required for Mcm2 loading when cells re-enter the cell cycle from quiescence.

Development of a quantitative forecasting system for Septoria tritici based on a long-term monitoring

Septoria tritici is the most important diseases in winter wheat in Schleswig-Holstein (northern Germany) and in many other regions over the world. But the disease severity as well as the timing of the epidemic progression varies between locations and seasons and so he influence on yield parameters like absolute yield or yield loss. To optimize the disease management a quantitative knowledge of the factors affecting the disease progression is necessary. Weather is the driving force of the disease progression, the weather from sowing until stem elongation influence mostly the disease severity on the lower leaves whereas the weather during the vegetation period determines the epidemic disease patterns of the upper yield relevant leaves (F-3 to flag leaf). The epidemic disease progression occurs in several pushes, also recognized as "sudden outbreaks", where such an increase is initiated by a weather scenario called infection cycle. The object of this study is the identification of the most important factors of each part of the disease progression and their interaction. So that weather scenarios as well as cropping parameters can be evaluated and recommendations for the disease management can be made.

Examining the biodegradation of endocrine disrupting bisphenol A and nonylphenol in WWTPs

The aim of this work was to examine biodegradation of the endocrine disrupting chemicals bisphenol A (BPA) and nonylphenol (NP) in activated sludge. Experiments were performed in a pilot wastewater treatment plant (WWTP) in Copenhagen, Denmark. During standard operation the BPA concentration was halved whereas the NP concentration was unchanged. Step-addition experiments showed that biomass adaptation to increased BPA and NP concentrations took 10 to more than 40 days depending on temperature, hydraulic retention time, and pre-exposure of the biomass. Mass-balance experiments showed that above 99% of the dosed BPA and 90% of the dosed NP is removed by biodegradation at steady-state. Batch experiments showed that BPA biodegradation occur solely under aerobic conditions. The work is believed to add vital knowledge to our understanding of parameters and processes governing biodegradation of EDCs in WWTPs.

Comparison of 68Ga-DOTATOC PET and 111In-DTPAOC (Octreoscan) SPECT in patients with neuroendocrine tumours

PURPOSE

Neuroendocrine tumours (NETs) can be imaged with scintigraphy using radiolabelled somatostatin analogues. The aim of our study was to compare the value of (68)Ga-DOTATOC PET and (111)In-DTPAOC SPECT (Octreoscan) in the detection of NET manifestations.

METHODS

Twenty-seven NET patients were prospectively examined. (68)Ga-DOTATOC PET and (111)In-DTPAOC SPECT were performed using standard techniques. Treatment was not applied in between. Mean and maximum standardised uptake values (SUVs) were calculated for PET findings. Tumour/non-tumour ratios were calculated for SPECT findings. Findings were compared by a region-by-region analysis and verified with histopathology, CT and MRI within 21 days.

RESULTS

SUVs of positive lesions on (68)Ga-DOTATOC PET ranged from 0.7 to 29.3 (mean SUV) and from 0.9 to 34.4 (maximum SUV). Tumour/non-tumour ratios on (111)In-DTPAOC SPECT ranged from 1.8 to 7.3. In imaging lung and skeletal manifestations, (68)Ga-DOTATOC PET was more efficient than (111)In-DTPAOC SPECT. All discrepant lung findings and 77.8% of discrepant osseous findings were verified as true positive PET interpretations. In regional comparison of liver and brain, (68)Ga-DOTATOC PET and (111)In-DTPAOC SPECT were identical. In lymph nodes, the pancreas and the gastro-intestinal system, different values of the two techniques were not indicated in regional analyses. In a single patient, surgical interventions were changed on the basis of (68)Ga-DOTATOC PET findings.

CONCLUSION

(68)Ga-DOTATOC PET is superior to (111)In-DTPAOC SPECT in the detection of NET manifestations in the lung and skeleton and similar for the detection of NET manifestations in the liver and brain. (68)Ga-DOTATOC PET is advantageous in guiding the clinical management.

Modelling as a tool when interpreting biodegradation of micro pollutants in activated sludge systems

The aims of the present work were to improve the biodegradation of the endocrine disrupting micro pollutant, bisphenol A (BPA), used as model compound in an activated sludge system and to underline the importance of modelling the system. Previous results have shown that BPA mainly is degraded under aerobic conditions. Therefore the aerobic phase time in the BioDenitro process of the activated sludge system was increased from 50% to 70%. The hypothesis was that this would improve the biodegradation of BPA. Both the influent and the effluent concentrations of BPA in the experiment dropped significantly after increasing the aerobic time. From simulations with a growth-based biological/physical/chemical process model it was concluded that although the simulated effluent concentration of BPA was independent of the influent concentration at steady-state, the observed drop in effluent concentrations probably was caused by either a larger specific biomass to influent BPA ratio, improved biodegradation related to the increased aerobic phase time, or a combination of the two. Thereby it was not possibly to determine if the increase in aerobic phase time improved the biodegradation of BPA. The work underlines the importance of combining experimental results with modelling when interpreting results from biodegradation experiments with fluctuating influent concentrations of micro pollutants.

Deregulated cyclin E promotes p53 loss of heterozygosity and tumorigenesis in the mouse mammary gland

Deregulation of cyclin E expression and/or high levels have been reported in a variety of tumors and have been used as indicators of poor prognosis. Although the role that cyclin E plays in tumorigenesis remains unclear, there is evidence that it confers genomic instability when deregulated in cultured cells. Here we show that deregulated expression of a hyperstable allele of cyclin E in mice heterozygous for p53 synergistically increases mammary tumorigenesis more than that in mice carrying either of these markers individually. Most tumors and tumor-derived cell lines demonstrated loss of p53 heterozygosity. Furthermore, this tumor susceptibility is related to the number of times the transgene is induced indicating that it is directly attributable to the expression of the cyclin E transgene. An indirect assay indicates that loss of p53 function is an early event occurring in the mammary epithelia of midlactation mammary glands in which cyclin E is deregulated long before evidence of malignancy. These data support the hypothesis that deregulated expression of cyclin E stimulates p53 loss of heterozygosity by promoting genomic instability and provides specific evidence for this in vivo. Cyclin E deregulation and p53 loss are characteristics often observed in human breast carcinoma.

[Comparison of diagnostic accuracy of (18)F-FDG PET, (123)I-IMT- and (99m)Tc-MIBI SPECT: evaluation of tumour progression in irradiated low grade astrocytomas]

AIM

To evaluates the diagnostic accuracy of the SPECT-tracers 3-(123)I-alpha-methyl-L-tyrosine (IMT) and (99m)Tc(I)- hexakis(2-methoxyisobutylisonitrile) (MIBI) as well as the PET-tracer 2-(18)F-2-deoxyglucose (FDG) for detecting tumour progression in irradiated low grade astrocytomas (LGA).

PATIENTS, METHODS

We examined 91 patients (56 males; 35 females; 44.7 +/- 11.5 years), initially suffering from histologically proven LGAs (mean WHO grade II) and treated by stereotactic radiotherapy (59.0 +/- 4.6 Gy). On average 21.9 +/- 11.2 months after radiotherapy, patients presented new Gd-DTPA enhancing lesions on MRI, which did not allow a differentiation between progressive tumour (PT) and non-PT (nPT) at this point of time. PET scans (n = 82) were acquired 45 min after injection of 208 +/- 32 MBq FDG. SPECT scans started 10 min after injection of 269 +/- 73 MBq IMT (n = 68) and 15 min after injection of 706 +/- 63 MBq MIBI (n = 34). Lesions were classified as PT and nPT based on prospective follow-up (clinically, MRI) for 17.2 +/- 9.9 months after PET/SPECT. Lesion-to-normal ratios (L/N) were calculated using contra lateraly mirrored reference regions for the SPECT examinations and reference regions in the contra lateral grey (GM) and white matter (WM) for FDG PET. Ratios were evaluated by Receiver Operating Characteristic (ROC) analysis.

RESULTS

In the patient groups nPT and PT, L/N ratios for FDG (GS) were 0.6 +/- 0.3 vs. 1.2 +/- 0.5 (p = 0.003), for FDG (WS) 1.2 +/- 0.4 vs. 2.6 +/- 0.4 (p < 0.001), for IMT 1.1 +/- 0.1 vs. 1.8 +/- 0.4 (p < 0.001) and for MIBI 1.6 +/- 0.7 vs. 2.6 +/- 2.2 (p = 0.554). Areas under the non-parametric ROC-curves were: 0.738 +/- 0.059 for FDG (GS), 0.790 +/- 0.057 for FDG (WS), 0.937 +/- 0.037 for IMT and 0.564 +/- 0.105 for MIBI.

CONCLUSION

MIBI-SPECT examinations resulted in a low accuracy and especially in a poor sensitivity even at modest specificity values. A satisfying diagnostic accuracy was reached with FDG PET. Using WM as reference region for FDG PET, a slightly higher AUC as compared to GM was calculated. IMT yielded the best ROC characteristics and the highest diagnostic accuracy for differentiating between PT and nPT in irradiated LGA.

Integrated modelling of two xenobiotic organic compounds

This paper presents a dynamic mathematical model that describes the fate and transport of two selected xenobiotic organic compounds (XOCs) in a simplified representation of an integrated urban wastewater system. A simulation study, where the xenobiotics bisphenol A and pyrene are used as reference compounds, is carried out. Sorption and specific biological degradation processes are integrated with standardised water process models to model the fate of both compounds. Simulated mass flows of the two compounds during one dry weather day and one wet weather day are compared for realistic influent flow rate and concentration profiles. The wet weather day induces resuspension of stored sediments, which increases the pollutant load on the downstream system. The potential of the model to elucidate important phenomena related to origin and fate of the model compounds is demonstrated.

Uncertainty and precaution in environmental management

In this paper, two different visions of the relationship between science and policy are contrasted with one another: the "modern" vision and the "precautionary" vision. Conditions which must apply in order to invoke the Precautionary Principle are presented, as are some of the main challenges posed by the principle. The following central question remains: If scientific certainty cannot be provided, what may then justify regulatory interventions, and what degree of intervention is justifiable? The notion of "quality of information" is explored, and it is emphasized that there can be no absolute definition of good or bad quality. Collective judgments of quality are only possible through deliberation on the characteristics of the information, and on the relevance of the information to the policy context. Reference to a relative criterion therefore seems inevitable and legal complexities are to be expected. Uncertainty is presented as a multidimensional concept, reaching far beyond the conventional statistical interpretation of the concept. Of critical importance is the development of methods for assessing qualitative categories of uncertainty. Model quality assessment should observe the following rationale: identify a model that is suited to the purpose, yet bears some reasonable resemblance to the "real" phenomena. In this context, "purpose" relates to the policy and societal contexts in which the assessment results are to be used. It is therefore increasingly agreed that judgment of the quality of assessments necessarily involves the participation of non-modellers and non-scientists. A challenging final question is: How to use uncertainty information in policy contexts? More research is required in order to answer this question.

Metabolische Bildgebung zur Verlaufskontrolle stereotaktisch bestrahlter Gliome - Wertigkeit der 1H-MR-Spektroskopie im Vergleich zur FDG-PET und IMT-SPECT

PURPOSE

To evaluate the clinical value of 1H MR spectroscopy (1H MRSI) for follow-up of irradiated glioma compared to positron emission tomography (PET) with [18F]-2-fluoro-deoxy-D-glucose (FDG-PET) and single photon emission tomography with [123I]-a-methyl-L-tyrosine (IMT-SPECT).

MATERIALS AND METHODS

Twenty-four patients with irradiated gliomas were examined using 1H MRSI (2D spectroscopic imaging; PRESS; TE = 135 msec; 1.5T Magnetom Vision, Siemens; Voxel size 9 x 9 x 15 mm (3)). MR spectra (n = 233) were evaluated in areas suspicious of tumor (n = 86) as well as in healthy appearing brain tissue (n = 147). Relative signal intensity ratios of choline (Cho), creatine (Cr) and N-acetyl-aspartate (NAA) were calculated. PET scans (n = 19) were performed with 200 - 250 MBq FDG, IMT-SPECT examinations (n = 14) with 200 - 250 mBq IMT. Based on clinical and MRI/CT, follow-up lesions were classified as either neoplastic [PT] or non-neoplastic [nPT].

RESULTS

True positive results for the diagnosis of PT/nPT were 88/89 % (1H MRSI), 73/100 % (PET) and 100/75 % (SPECT). Cho/Cr showed highly significant changes for PT. Determinating a correlation between Cho, Cr, NAA and IMT-SPECT as well as FDG-PET was not possible because of different location of maximum tracer uptake and acquired 2D 1H MRSI.

CONCLUSION

IMT-SPECT seems to be superior to detect tumor progression in irradiated gliomas. 1H MRSI was more suitable than FDG-PET to differentiate between recurrence and radiation-induced changes. FDG-PET plays a role as sensitive method for detecting high-grade tumors. PET and SPECT allowed the examination of the entire tumor including surrounding brain tissue with higher spatial resolution than the acquired 2D 1H MRSI. A main limitation of our study was that only 2D 1H MRSI was used, with only parts of the tumor evaluated. The use of 3D MR spectroscopic imaging may further increase the diagnostic accuracy.

[High resolution reconstruction of PET images using the iterative OSEM algorithm]

AIM

Improvement of the spatial resolution in positron emission tomography (PET) by incorporation of the image-forming characteristics of the scanner into the process of iterative image reconstruction.

METHODS

All measurements were performed at the whole-body PET system ECAT EXACT HR(+) in 3D mode. The acquired 3D sinograms were sorted into 2D sinograms by means of the Fourier rebinning (FORE) algorithm, which allows the usage of 2D algorithms for image reconstruction. The scanner characteristics were described by a spatially variant line-spread function (LSF), which was determined from activated copper-64 line sources. This information was used to model the physical degradation processes in PET measurements during the course of 2D image reconstruction with the iterative OSEM algorithm. To assess the performance of the high-resolution OSEM algorithm, phantom measurements performed at a cylinder phantom, the hotspot Jaszczack phantom, and the 3D Hoffmann brain phantom as well as different patient examinations were analyzed.

RESULTS

Scanner characteristics could be described by a Gaussian-shaped LSF with a full-width at half-maximum increasing from 4.8 mm at the center to 5.5 mm at a radial distance of 10.5 cm. Incorporation of the LSF into the iteration formula resulted in a markedly improved resolution of 3.0 and 3.5 mm, respectively. The evaluation of phantom and patient studies showed that the high-resolution OSEM algorithm not only lead to a better contrast resolution in the reconstructed activity distributions but also to an improved accuracy in the quantification of activity concentrations in small structures without leading to an amplification of image noise or even the occurrence of image artifacts.

CONCLUSION

The spatial and contrast resolution of PET scans can markedly be improved by the presented image restauration algorithm, which is of special interest for the examination of both patients with brain disorders and small animals.

Monitoring individual response to brain-tumour chemotherapy: proton MR spectroscopy in a patient with recurrent glioma after stereotactic radiotherapy

Since antineoplastic activity varies, sensitive methods for individual assessment of efficacy are needed. We demonstrate the clinical value of MR spectroscopy in monitoring chemotherapy in a patient with recurrent glioma after stereotactic radiotherapy. Diagnostic imaging before and after chemotherapy included contrast-enhanced MRI, single-voxel proton MR spectroscopy ((1)H MRS), (1)H MR spectroscopic imaging ((1)H SI), and fluorodeoxyglucose (FDG) positron-emission tomography (PET). A significant decrease in choline signal intensity was observed 2 months after chemotherapy indicating tumour chemosensitivity, in line with tumour shrinkage on MRI and decreased uptake of FDG. Assessment of early response by MRS may help to improve treatment protocols in other patients.

Monitoring toxicity of industrial wastewater and specific chemicals to a green alga, nitrifying bacteria and an aquatic bacterium

Treatment plants may be exposed to a whole range of toxic organic and inorganic compounds that may inhibit the removal of organic matter and nitrogen. In order to secure maximum treatment efficiency, the plant manager has to monitor the toxicity of the influent sewage. With regard to the receiving water the manager also has to make sure that toxicity in the influent is significantly reduced during treatment. Because a whole range of chemicals may be present, chemical analysis may be insufficient and expensive as a control instrument. Instead, direct toxicity measurements are preferable to capture the complexity of the wastewater. The monitoring methods have to be relevant and sensitive for the processes in the treatment plant, i.e. removal of organic matter and nutrients. The methods also have to be simple and inexpensive. The paper reports on recent results from the application of nitrification, algae and Biotox tests, and summarises the experience with monitoring of toxicity. Although the sensitivity of the tests varies with respect to individual chemicals or group of chemicals, the application of a combination of the tests gives a high likelihood of detecting toxic impacts on treatment plants and receiving waters.

Diagnostik mittels 18F-FDG-PET nach Larynxorganerhalt durch prim�re Radiochemotherapie

PATIENTS AND METHODS

In a group of 20 patients undergoing chemoradiation for larynx organ preservation after diagnosis of laryngeal and hypopharyngeal carcinoma, (18)F-fluordeoxyglucose positron emission tomography ((18)F-FDG-PET) was performed before the start of therapy. After i.v. application of 240 MBq FDG, a dynamic PET in 3-D-mode was performed over 90 min (Siemens CTI ECAT EXACT HR(+)). Analysis was done visually and semiquantitatively (60-90 min p.i.) following iterative reconstruction. Additional (18)F-FDG-PET investigations were done and correlated with the clinical outcome in 16/20 patients at 3 months and in 14/20 patients at 6 months after the end of therapy.

RESULTS

In 17/20 patients (85%), the preclinical (18)F-FDG-PET correlated well with the histologically confirmed primary tumor. Three cases were false negatives. In one case this was due to an increased glucose value (203 mg%). After 3 months, 8/13 (62%) patients showed a positive correlation between clinical and PET results (sensitivity 100%, specificity 70%). After 6 months, 9/11 (82%) patients presented clinically normal PET results. PET results were false negative in one case (sensitivity 67%, specificity 88%).

CONCLUSION

The data of our trial slightly reduce the enthusiasm of early (18)F-FDG-PET detection of residual disease after chemoradiation in resectable laryngeal or hypopharyngeal cancer. Further trials should optimize the calculation integrating the exact quantification of glucose metabolism with the aim of improving sensitivity and specificity.

Environmental engineering education for developing countries: framework for the future

This paper presents the existing philosophy, approach, criteria and delivery of environmental engineering education (E3) for developing countries. In general, environmental engineering is being taught in almost all major universities in developing countries, mostly under civil engineering degree programmes. There is an urgent need to address specific inputs that are particularly important for developing countries with respect to the reality of urbanisation and industrialisation. The main component of E3 in the near future will remain on basic sanitation in most developing countries, with special emphasis on the consumer-demand approach. In order to substantially overcome environmental problems in developing countries, E3 should include integrated urban water management, sustainable sanitation, appropriate technology, cleaner production, wastewater minimisation and financial framework.

Somatostatin analogue scintigraphy in Merkel cell tumours

BACKGROUND

Merkel cell tumours are rare neoplasms of the skin with frequent regional and distant metastases. Scintigraphy with the radiolabelled somatostatin analogue octreotide is a possible method for in vivo localization of the primary tumour and its metastases.

OBJECTIVES

To estimate the diagnostic value of indium (111) -octreotide scintigraphy (Octreoscan in detecting metastases.

METHODS

Scans of 11 patients with Merkel cell carcinoma were evaluated, in whom scintigraphy was performed in addition to the conventional investigations, chest X-ray, ultrasonography and computed tomography (CT).

RESULTS

In four cases metastases were found both by scintigraphy and by conventional methods; two investigations showed a suspicious accumulation of radioactivity on scintigraphy that could not be confirmed by CT and clinical progression. In three cases CT-verified metastases were not found by scintigraphy. Two patients were found to be tumour free, i.e. free of metastases by scintigraphy and conventional methods, indicating true-negative results.

CONCLUSION

These data confirm that scintigraphy with the radiolabelled somatostatin analogue octreotide is not clinically helpful in detecting metastases from Merkel cell carcinoma. In this relatively small sample the method generated false-positive or false-negative results in five of 11 cases.

Switching of melanocyte pigmentation associated with pituitary pars intermedia tumors in Rb+/- and p27-/- female mice with yellow pelage

As an incidental finding in a study of mammary tumorigenesis, two lines of genetically engineered mice were observed to develop pigmentation changes of the fur. Mice with targeted mutations of the Rb1 (Rb) and Cdkn1b (p27kip1) genes were crossed from C57BL/6 (black coat color; eumelanin) and 129Sv (wild-type agouti coat color) backgrounds, respectively, to one with a dominant yellow coat color (phaeomelanin) carrying a transgene for Agouti under a keratinocyte specific promoter. Both Rb+/- and p27-/- mice developed pituitary tumors of the pars intermedia that were associated with a switch to black (eumelanic) fur but were not observed in sibling Rb+/+ and p27+/+ mice. This phenomenon was observed first in the vibrissae and, subsequently one to two weeks later, as periorbital and dorsal patches, and was associated with pituitary lesions larger than four millimeters in the longest dimension. In Rb+/- mice, pigmentation change preceded a moribund state attributable to the tumors by two to four weeks, whereas in p27-/- mice, the pigmentation alteration was earlier, more gradual, and prolonged. The switch from phaeomelanin to eumelanin in the fur is most likely due to out-competition of the agouti gene product by alpha-melanocyte-stimulating hormone from the pituitary tumors, an effect masked in black or agouti mice.

Feasibility study of sequencing batch reactor system for upgrading wastewater treatment in Malaysia

The objective of this study was to assess the feasibility of the Sequencing Batch Reactor (SBR) system for implementation in Malaysia. Theoretical, field, laboratory investigations, and modelling simulations have been carried out. The results of the study indicated that the SBR system was robust, relatively cost-effective, and efficient under Malaysian conditions. However, the SBR system requires highly skilled operators and continuous monitoring. This paper also attempted to identify operating conditions for the SBR system, which optimise both the removal efficiencies and the removal rates. The removal efficiencies could reach 90-96% for COD, up to 92% for TN, and 95% for SS. An approach to estimate a full operational cycle time, to estimate the de-sludging rate, and to control the biomass in the sludge has also been developed. About 4 hours react time was obtained, as 2.25 hours of nitrification with aerated slow fill and 1.75 hour of denitrification with HAc addition as an additional carbon source. Inefficient settling was one of the problems that affect the SBR effluent quality. The settling time was one hour for achieving Standard B (effluent quality) and 2 hours for Standard A.

Discrimination between Alzheimer dementia and controls by automated analysis of multicenter FDG PET

A new diagnostic indicator of FDG PET scan abnormality, based on age-adjusted t statistics and an automated voxel-based procedure, is presented and validated in a large data set comprising 110 normal controls and 395 patients with probable Alzheimer's disease (AD) that were studied in eight participating centers. The effect of differences in spatial resolution of PET scanners was minimized effectively by filtering and masking. In controls FDG uptake declined significantly with age in anterior cingulate and frontolateral perisylvian cortex. In patients with probable AD decline of FDG uptake in posterior cingulate, temporoparietal, and prefrontal association cortex was related to dementia severity. These effects were clearly distinct from age effects in controls, suggesting that the disease process of AD is not related to normal aging. Women with probable AD had significantly more frontal metabolic impairment than men. The new indicator of metabolic abnormality in AD-related regions provided 93% sensitivity and specificity for distinction of mild to moderate probable AD from normals, and 84% sensitivity at 93% specificity for detection of very mild probable AD (defined by Mini Mental Score 24 or better). All regions related to AD severity were already affected in very mild AD, suggesting that all vulnerable areas are affected to a similar degree already at disease onset. Ventromedial frontal cortex was also abnormal. In conclusion, automated analysis of multicenter FDG PET is feasible, provides insights into AD pathophysiology, and can be used potentially as a sensitive biomarker for early AD diagnosis.

Comparison of pharmacokinetic MRI and [18F] fluorodeoxyglucose PET in the diagnosis of breast cancer: initial experience

It was the aim of this methodology-oriented clinical pilot study to compare the potential of dynamic MRI and 2-[18F]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) for the detection and characterization of breast cancer. Fourteen women with suspicious breast lesions were examined. The MRI data were acquired with a turbo fast low-angle shot sequence and analyzed using a pharmacokinetic model. Emission data were detected in the sensitive 3D modus, iteratively reconstructed, and superimposed onto corresponding transmission images. In the 14 patients, 13 breast masses with a suspicious contrast enhancement and FDG uptake were detected. For these lesions, no statistically significant correlation between evaluated MR and PET parameters was found. Of the 9 histologically confirmed carcinomas, 8 were correctly characterized with MRI and PET. Two inflammatory lesions were concordantly classified as cancer. Moreover, dynamic MRI yielded another false-positive finding. In 6 patients, PET detected occult lymph node and/or distant metastases. Although both functional imaging techniques provide independent tissue information, the results concerning the diagnosis of primary breast lesions were almost identical. An advantage of PET, however, is its ability to localize lymph node involvement and distant metastases as an integral part of the examination.