Insights into Bone Metabolism of Avian Embryos In Ovo Via 3D and 4D 18F-fluoride Positron Emission Tomography

Purpose

The chick embryo is a well-known economical in vivo model system and is widely applied in preclinical research, e.g., bone development studies. It is therefore surprising that no studies concerning the application of ¹⁸F-fluoride microPET to bone metabolism have been reported so far. This may be due to motion artifacts or the lack of convenient tracer injection sites.

Methods

We resolved the above problems using a combination of sample preparation, anesthesia, microPET imaging, and computational processing, and describe a convenient way of visualizing three- and four- dimensional features of bone metabolism in living chick embryos.

Results

The application of ¹⁸F-fluoride microPET facilitates repeat measurements, highly reproducible and motion-artifact-free skeletal imaging, and provides quantitative measurements of in ovo metabolic activities in the bones of developing chick. During microPET measurement, radio tracer was injected intravascularly using a custom-made catheter system, allowing us to additionally investigate early time points in tracer kinetics and uptake.

Conclusions

Our results show that bone metabolism in living chick embryos can be reproducibly studied and quantified in ovo, even for multiple tracer injections over a longer time period. The use of dynamic ¹⁸F-fluoride microPET imaging made it possible to visualize and analyze even small bone structures with excellent quality. Moreover, as our data are comparable to data from corresponding rodent experiments, the use of embryonated chicken eggs is a convenient and economical alternative to other animal models.     

Comparison of radiation treatment delivery for pancreatic cancer: Linac intensity-modulated radiotherapy versus helical tomotherapy

Introduction: Intensity‐modulated radiotherapy (IMRT) has been shown to reduce dose to organs at risk (OAR) while adequately treating tumour volume. This study quantitatively compares the dosimetric differences from step‐and‐shoot IMRT compared with helical tomotherapy (HT) for pancreatic head cancer. Methods: Twelve consecutive patients with non‐metastatic, stage T3 or T4, unresectable pancreatic head cancer were planned for step‐and‐shoot IMRT as well as HT. Radiotherapy was planned to deliver 45.9 Gy to the clinical target volume in 30 fractions with an integrated boost to 54 Gy to the gross tumour volume (planning target volume 5400 including a 1‐cm set‐up margin). The uniformity index (UI) and conformity index (CI) were used to compare the quality of target coverage, while the quality index (QI) compared the dosimetric performance for OAR. Results: Both methods were effective at covering the tumour with no significant difference in UI or CI. However, HT dosimetry exhibited superior sparing of OAR with significantly less stomach (mean QI_StomV30 = 0.84, P = 0.006) and small bowel dosing (mean small bowel QI_SBV30 = 0.84, P = 0.005). HT reduced dose to the kidney receiving the highest dose but the overall volume of kidney receiving 18 Gy was not significantly different between the two systems, indicating that HT spread the dose more uniformly through the kidneys. Conclusions: Target coverage is equivalent between the two systems; however, HT shows significantly better sparing of the stomach and small bowel. The decreased dose to OAR with HT is likely to improve the therapeutic ratio in the radiotherapy of pancreatic head cancers.     

Patterns and diagnostic value of cardiac troponin I vs. troponin T and CKMB after OPCAB surgery.

BACKGROUND: Cardiac troponin I (cTnI) has been shown to be a specific marker for myocardial injury in cardiac surgery. The object of this prospective study was to determine the patterns and kinetic and diagnostic value of cTnI, cardiac troponin T (cTnT), and creatine kinase MB (CKMB) activity after minimally invasive coronary revascularization using an octopus device on the beating heart (OPCAB). METHODS: 48 patients (33 male/15 female, mean age 68.3 +/- 8.7 years) underwent their first elective OPCAB surgery with median sternotomy without mortality. The mean number of grafts was 2.0 +/- 0.8 per patient. Preoperative mean ejection fraction was 56.6 % +/- 14.9%. CTnI and T levels, total creatine kinase (CK) and CK-MB activity in the serum were measured before operation, at arrival at the ICU, and 6, 12, 24, 48 and 120 hours afterward. Serial 12-lead ECGs were recorded preoperatively and at days 1, 2 and 5. The relationship between perioperative data and postoperative cTnI and cTnT levels and CKMB were statistically identified for all variables. RESULTS: The best cutoff value for cTnI was 8.35 micrograms/l. The patients were grouped by the ECG findings and maximal slopes of cTnI postoperatively (group I: unchanged ECG and cTnI < 8.35 micrograms/l, n = 38; group II: unchanged ECG and cTnI > 8.35 micrograms/l n = 6; group III: Q-wave in ECG and cTnI > 8.35 micrograms/l, n = 4). Baseline serum concentrations of cTnI were in the normal range, and significantly increased after surgery with a peak 24h after the operation. Maximal slopes of cTnI ranged in group II between 9.1 and 18.0 micrograms/l, and in group III between 35.9 and 88.8 micrograms/l. There was strong concordance between maximum cTnI, cTnT (p < 0.0001) and CK-MB levels (p = 0.003). First cTnI levels immediately post-op correlated with the maximum cTnI levels during the postoperative course (p = 0.009). CONCLUSIONS: CTnI after minimal invasive surgery shows a characteristic pattern with a maximum at 24h after the operation. The measurement of postoperative biochemical marker concentrations, specially cTnI, reflects myocardial injury incurred during the procedure. It is an accurate method for confirming or excluding a perioperative myocardial injury diagnosis after OPCAB surgery.     

Outcome and prognostic factors in patients with brain metastases from small-cell lung cancer treated with whole brain radiotherapy

Journal of Neuro-Oncology - The purpose of this study was to evaluate prognostic factors associated with overall survival (OS) and neurological progression free survival (nPFS) in small-cell lung...     

Untersuchungen über Poly(arylenvinylen)e, 9. Zusammenhang zwischen der chemischen Struktur und der photoelektrischen Empfindlichkeit von Polyxylylidenen

In a series of differently substituted and isomeric poly(arylenevinylene)s (polyxylylidenes) it was found, that with the undoped polymers there is the relation (1) between the optical excitation energy E_opt and the photoelectrical sensitivity J_Ph. This relation is discussed on the basis of a photochemical ionization of the macromolecules.     

The value of fluorodeoxyglucose positron emission tomography (FDG-PET) in differentiation of pancreatic lesions

Fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) is a functional imaging modality that is based on the metabolic activity which is higher in most malignant tumors than benign tissues. This short review describes the basics of FDG-PET and gives a discussion of its role in differentiation of focal pancreatic lesions. The diagnostic accuracy in patients with active inflammation or cancer of the pancreas can be improved by dynamic acquisition of focal pancreatic lesions.     

Untersuchungen über Poly(arylenvinylene), 30. Synthese,Photoleitfähigkeit und Redox-Verhalten von Poly(9-methylcarbazol-3,6-diyl-1,2-diphenylvinylen)

Soluble poly(9-methylcarbazole-3,6-diyl-1,2-diphenylvinylene) ( 1 ) M _n = 10000, was prepared by dehalogenating polycondensation of 3,6-bis(α,α-dichlorobenzyl)-9-methylcarbazole with chromium(II) acetate. The monomer was obtained from 3,6-dibenzoyl-9-methylcarbazole by reaction with PCl₅. The chemical structure of 1 was verified by elemental analysis, UV, IR, and NMR spectroscopy, GPC, and VPO. 1 was found to be highly photoconducting, exhibiting a dark conductivity of 10^?14 S/cm, which increases on doping with AsF₅ to 10^?4 S/cm. Its thermal stability under nitrogen is as high as with other phenylsubstituted poly(arylenevinylene)s (dec. temp.: 540°C; residue: 72 weight-%). The spectral distribution of sensitized (TNF, dyes) photoconductivity was studied and the redox behaviour was investigated by cyclovoltammetry. The redox potentials were found to be E = 0,90 V and E = ?2,07 V (vs. Ag/AgCl). The electrochemical oxidation is reversible, associated with the formation of polydications derived from chain segments which consist of two carbazolediylvinylene units. Thus, 1,2-dicarbazole-3-yl-1,2-diphenylethylene as model compound well reflects the redox properties of the polymer. The electrochemical band gap energy was found to be 2,97 eV, which agrees closely with the energy of the optical absorption edge of 3,04 eV.     

Detection of the plasma volume expander hydroxyethyl starch in human urine

The plasma volume expander hydroxyethyl starch (HES) is usually administered in cases of hypovolaemic shocks but in 1998 the press reported its misuse in endurance sports. Since January 2000, it has been put on the list of prohibited substances of the International Olympic Committee (IOC) and its misuse is to ban by doping controls. Therefore, a rapid method enabling the screening for HES in human urine was developed which can be easily adopted by IOC laboratories to analyse routine urine samples for this remedy. Excretion study urine samples obtained from patients treated with HES, blank urine specimen and reference standards, were hydrolysed with hydrochloric acid and without any further purification of the resulting monosaccharides their per-timethylsilylated derivatives were performed. By means of gas chromatography-mass spectrometry the products were separated and the alpha- and beta-isomers of glucose, 2-, 3- and 6-hydroxyethyl glucose derivatives were identified. Typical ion traces of 2- and 3-substituted glucose (m/z 248, m/z 261 and m/z 235, m/z 248, respectively) support the fast determination of the substances whose electron impact mass spectra are presented and discussed.