SU-E-I-29: Dose Rate and Image Quality Comparison Between Philips Veradius and GE OEC 9900 Elite Fluoroscopic C-Arms

PURPOSE

The radiation dose rate and image quality were compared on GE OEC 9900 Elite Vas 8 and Philips Veradius fluoroscopic C-arms.

METHODS

Plastic (PMMA) phantoms were used to simulate various thicknesses of soft tissues encountered during fluoroscopically-guided interventional procedures while aluminum and copper phantoms were used to simulate extremities of different sizes. An image quality test tool and an ionization chamber were included in the setup of each phantom. The phantoms were imaged in several fluoroscopy modes and at different dose levels. The entrance surface air KERMA rate (ESAKR) was measured for each phantom in each fluoroscopy mode. Simultaneously, the image quality was assessed by counting the number of low-contrast objects visible in the image quality test tool. For a given phantom type and thickness, the ESAKR was plotted versus the number of visible low-contrast objects to compare the dose rate required for a given level of image quality. Additionally, the mean ESAKR per number of objects was calculated and p-values were used to test for statistically significant differences between the C-arms.

RESULTS

For comparable image quality with a given phantom type and thickness the ESAKR with the OEC was typically much higher than with the Veradius. One-tailed, unpaired t-tests confirm that the mean ESAKR per number of visible low-contrast objects was lower for the Veradius than for the OEC with all thicknesses of PMMA (p < 0.05). The differences for the aluminum and copper phantoms were much smaller and were not statistically significant (p-values ranged from 0.2 to 0.47).

CONCLUSION

In general, the Veradius C-arm provided better low-contrast image quality during fluoroscopy, with lower ESAKR than the OEC 9900 Elite Vas 8. The differences were statistically significant only with PMMA phantoms. Funding support provided by Philips Healthcare (Bothell, WA).

Implication of the oep16-1 mutation in a flu-independent, singlet oxygen-regulated cell death pathway in Arabidopsis thaliana

Singlet oxygen is a prominent form of reactive oxygen species in higher plants. It is easily formed from molecular oxygen by triplet-triplet interchange with excited porphyrin species. Evidence has been obtained from studies on the flu mutant of Arabidopsis thaliana of a genetically determined cell death pathway that involves differential changes at the transcriptome level. Here we report on a different cell death pathway that can be deduced from the analysis of oep16 mutants of A. thaliana. Pure lines of four independent OEP16-deficient mutants with different cell death properties were isolated. Two of the mutants overproduced free protochlorophyllide (Pchlide) in the dark because of defects in import of NADPH:Pchlide oxidoreductase A (pPORA) and died after illumination. The other two mutants avoided excess Pchlide accumulation. Using pulse labeling and polysome profiling studies we show that translation is a major site of cell death regulation in flu and oep16 plants. flu plants respond to photooxidative stress triggered by singlet oxygen by reprogramming their translation toward synthesis of key enzymes involved in jasmonic acid synthesis and stress proteins. In contrast, those oep16 mutants that were prone to photooxidative damage were unable to respond in this way. Together, our results show that translation is differentially affected in the flu and oep16 mutants in response to singlet oxygen.

Delayed referral despite appropriate knowledge in cryptorchidism as a cause of delayed orchidopexies in Austria

AIM

Guidelines recommend early orchidopexy in cryptorchidism to decrease the risk of infertility and tumor formation. We aimed to asses if a delayed initial presentation for cryptorchidism was due to unawareness of these guidelines or for any other reasons.

METHODS

A short questionnaire exploring timing and referral habits when assessing children with cryptorchidism was sent by email to all registered pediatricians in Austria. Comparatively, a chart review of performed orchidopexies was performed at our institution.

RESULTS

Of 369 registered pediatricians, 102 (27.6%) returned valid questionnaires. The average maximum age at which pediatricians in Austria suggested treatment of cryptorchidism was the 21.2 (8.4 months standard deviation (SD)) month of life. Assessment of testicular descent was reported to be regularly performed until the 8.8 (3-18 years SD) year of life. In contrast, from 1997-2008, 730 boys were treated surgically for cryptorchidism at our department. The mean age at operation was 3.4 years (3.1 years SD).

CONCLUSION

The majority of pediatricians in Austria know the correct timing for treatment of cryptorchidism. Nevertheless, orchidopexies are still carried out to later than suggested by international guidelines. Further studies and analysis to evaluate the reasons for these suboptimal referring patterns coupled with further communication improvements between pediatricians and surgeons are needed.

Evaluating the cytotoxicity of palladium/magnetite nano-catalysts intended for wastewater treatment

Palladium/magnetite nanoparticulate catalysts were developed for efficient elimination of halogenated organic pollutants from contaminated wastewater. Particle recovery from treated water can be ensured via magnetic separation. However, in worst-case scenarios, this catalyst removal step might fail, leading to particle release into the environment. Therefore, a toxicological study was conducted to investigate the impact of both pure magnetite and palladium/magnetite nanoparticle exposure upon human skin (HaCaT) and human colon (CaCo-2) cell lines and a cell line from rainbow trout gills (RTgill-W1). To quantify cell viability after particle exposure, three endpoints were examined for all tested cell lines. Additionally, the formation of reactive oxygen species was studied for the human cells. The results showed only minor effects of the particles on the tested cell systems and support the assumption that palladium/magnetite nano-catalysts can be implemented for a new wastewater treatment technology in which advantageous catalyst properties outweigh the risks.

Plant oxylipins: role of jasmonic acid during programmed cell death, defence and leaf senescence

Plants are continuously challenged by a variety of abiotic and biotic cues. To deter feeding insects, nematodes and fungal and bacterial pathogens, plants have evolved a plethora of defence strategies. A central player in many of these defence responses is jasmonic acid. It is the aim of this minireview to summarize recent findings that highlight the role of jasmonic acid during programmed cell death, plant defence and leaf senescence.

Agglomeration of tungsten carbide nanoparticles in exposure medium does not prevent uptake and toxicity toward a rainbow trout gill cell line

Due to their increased production and use, engineered nanoparticles are expected to be released into the aquatic environment where particles may agglomerate. The aim of this study was to explore the role of agglomeration of nanoparticles in the uptake and expression of toxicity in the rainbow trout (Oncorhynchus mykiss) gill cell line, RTgill-W1. This cell line was chosen as model because it is known to be amenable to culture in complete as well as greatly simplified exposure media. Nano-sized tungsten carbide (WC) with or without cobalt doping (WC-Co), two materials relevant in the heavy metal industry, were applied as model particles. These particles were suspended in culture media with decreasing complexity from L15 with 10% fetal bovine serum (FBS) to L15 to L15/ex, containing only salts, galactose and pyruvate of the complete medium L15. Whereas the serum supplement in L15 retained primary nanoparticle suspensions, agglomerates were formed quickly in L15 and L15/ex. Nevertheless, scanning electron microscopy (SEM) coupled with energy dispersive X-ray (EDX) elemental analysis revealed an uptake of both WC and WC-Co nanoparticles into RTgill-W1 cells irrespective of the state of agglomeration of nanoparticles. The localisation seemed to be restricted to the cytoplasm, as no particles were observed in the nucleus of cells. Moreover, reduction in cell viability between 10 and 50% compared to controls were observed upon particle exposure in all media although the pattern of impact varied depending on the medium and exposure time. Short-term exposure of cells led to significant cytotoxicity at the highest nominal particle concentrations, irrespective of the particle type or exposure medium. In contrast, long-term exposures led to preferential toxicity in the simplest medium, L15/ex, and an enhanced toxicity by the cobalt-containing WC nanoparticles in all exposure media. The composition of the exposure media also influenced the toxicity of the cobalt ions, which may dissolve from the WC-Co nanoparticles, with cells reacting much more sensitively toward cobalt ions in the absence of FBS. However, the toxicity observed by ionic cobalt alone did not explain the toxicity of the WC-Co nanoparticles, suggesting that the combination of metallic Co and WC is the cause of the increased particle toxicity of WC-Co. Taken together, our findings indicate that minimal exposure media can lead to rapid agglomeration of nanoparticles but that agglomeration does not prevent uptake into cells and the expression of toxicity.

Toxicity of tungsten carbide and cobalt-doped tungsten carbide nanoparticles in mammalian cells in vitro

BACKGROUND

Tungsten carbide nanoparticles are being explored for their use in the manufacture of hard metals. To develop nanoparticles for broad applications, potential risks to human health and the environment should be evaluated and taken into consideration.

OBJECTIVE

We aimed to assess the toxicity of well-characterized tungsten carbide (WC) and cobalt-doped tungsten carbide (WC-Co) nanoparticle suspensions in an array of mammalian cells.

METHODS

We examined acute toxicity of WC and of WC-Co (10% weight content Co) nanoparticles in different human cell lines (lung, skin, and colon) as well as in rat neuronal and glial cells (i.e., primary neuronal and astroglial cultures and the oligodendrocyte precursor cell line OLN-93). Furthermore, using electron microscopy, we assessed whether nanoparticles can be taken up by living cells. We chose these in vitro systems in order to evaluate for potential toxicity of the nanoparticles in different mammalian organs (i.e., lung, skin, intestine, and brain).

RESULTS

Chemical-physical characterization confirmed that WC as well as WC-Co nanoparticles with a mean particle size of 145 nm form stable suspensions in serum-containing cell culture media. WC nanoparticles were not acutely toxic to the studied cell lines. However, cytotoxicity became apparent when particles were doped with Co. The most sensitive were astrocytes and colon epithelial cells. Cytotoxicity of WC-Co nanoparticles was higher than expected based on the ionic Co content of the particles. Analysis by electron microscopy demonstrated presence of WC nanoparticles within mammalian cells.

CONCLUSIONS

Our findings demonstrate that doping of WC nanoparticles with Co markedly increases their cytotoxic effect and that the presence of WC-Co in particulate form is essential to elicit this combinatorial effect.

The diagnostic contribution of indocyanine green to fluorescein angiography in fellow drusen eyes of patients with wet age-related macular degeneration

PURPOSE

To assess the contribution of indocyanine green angiography (ICGA) to fluorescein angiography (FA) in evaluating fellow drusen eyes of patients with wet age-related macular degeneration (AMD) in the other eye.

METHODS

The records of paired FA and ICGA of patients with dry AMD in one eye and wet AMD in the other eye were retrospectively reviewed. Based on color fundus photographs, drusen were graded to low, moderate, or high grade of severity on FA. The FA and ICGA findings were compared.

RESULTS

Fifty-two pairs of eyes were included. Fluorescein angiography showed drusen of low severity in 11 (21.2%) eyes, of moderate severity in 31 (59.6%), and of high severity in 10 (19.2%). Leakage on both FA and ICGA was not demonstrated in any case of drusen of low or moderate severity. Only in 2 out of 10 eyes from the high severity group, 3.8% of the eyes of the whole study population, did ICGA reveal occult choroidal neovascularization (CNV) that was not observed on FA.

CONCLUSIONS

In selected eyes with drusen of high grade severity, ICGA may detect occult CNV, unrecognized clinically or by FA. ICGA had a small contribution to the diagnosis of occult CNV in fellow drusen eyes with any degree of severity.

A plant porphyria related to defects in plastid import of protochlorophyllide oxidoreductase A

The plastid envelope of higher plant chloroplasts is a focal point of plant metabolism. It is involved in numerous pathways, including tetrapyrrole biosynthesis and protein translocation. Chloroplasts need to import a large number of proteins from the cytosol because most are encoded in the nucleus. Here we report that a loss-of-function mutation in the outer plastid envelope 16-kDa protein (oep16) gene causes a conditional seedling lethal phenotype related to defects in import and assembly of NADPH:protochlorophyllide (Pchlide) oxidoreductase A. In the isolated knockout mutant of Arabidopsis thaliana, excess Pchlide accumulated in the dark operated as photosensitizer and provoked cell death during greening. Our results highlight the essential role of the substrate-dependent plastid import pathway of precursor Pchlide oxidoreductase A for seedling survival and the avoidance of developmentally programmed porphyria in higher plants.

A role of Toc33 in the protochlorophyllide-dependent plastid import pathway of NADPH:protochlorophyllide oxidoreductase (POR) A

NADPH:protochlorophyllide oxidoreductase (POR) A is a key enzyme of chlorophyll biosynthesis in angiosperms. It is nucleus-encoded, synthesized as a larger precursor in the cytosol and imported into the plastids in a substrate-dependent manner. Plastid envelope membrane proteins, called protochlorophyllide-dependent translocon proteins, Ptcs, have been identified that interact with pPORA during import. Among them are a 16-kDa ortholog of the previously characterized outer envelope protein Oep16 (named Ptc16) and a 33-kDa protein (Ptc33) related to the GTP-binding proteins Toc33 and Toc34 of Arabidopsis. In the present work, we studied the interactions and roles of Ptc16 and Ptc33 during pPORA import. Radiolabeled Ptc16/Oep16 was synthesized from a corresponding cDNA and imported into isolated Arabidopsis plastids. Crosslinking experiments revealed that import of 35S-Oep16/Ptc16 is stimulated by GTP. 35S-Oep16/Ptc16 forms larger complexes with Toc33 but not Toc34. Plastids of the ppi1 mutant of Arabidopsis lacking Toc33, were unable to import pPORA in darkness but imported the small subunit precursor of ribulose-1,5-bisphosphate carboxylase/oxygenase (pSSU), precursor ferredoxin (pFd) as well as pPORB which is a close relative of pPORA. In white light, partial suppressions of pSSU, pFd and pPORB import were observed. Our results unveil a hitherto unrecognized role of Toc33 in pPORA import and suggest photooxidative membrane damage, induced by excess Pchlide accumulating in ppi1 chloroplasts because of the lack of pPORA import, to be the cause of the general drop of protein import.

The outer plastid envelope protein Oep16: role as precursor translocase in import of protochlorophyllide oxidoreductase A

A 16-kDa plastid envelope protein was identified by chemical crosslinking that interacts with the precursor of NADPH:protochlorophyllide oxdidoreductase A (pPORA) during its posttranslational import into isolated barley chloroplasts. Protein purification and subsequent protein sequencing showed that the 16-kDa protein is an ortholog of a previously identified outer plastid envelope protein, Oep16. A protein of identical size was present in barley etioplasts and interacted with pPORA. Similar 16-kDa protein-dependent crosslink products of pPORA were detected in wheat, pea, and Arabidopsis chloroplasts. Database analyses revealed that the 16-kDa protein belongs to a family of preprotein and amino acid transporters found in free-living bacteria and endosymbiotic mitochondria and chloroplasts. Antibodies raised against the 16-kDa protein inhibited import of pPORA, highlighting its role in protein import.

Combined pentalogy of Cantrell with tetralogy of Fallot, gallbladder agenesis, and polysplenia: a case report

A male newborn with pentalogy of Cantrell, tetralogy of Fallot, agenesis of the gallbladder, and polysplenia died at 3 days of age. Polysplenia was not previously reported in this association.

Optimization of a synthetic arginine receptor. Systematic tuning of noncovalent interactions

The simple arginine binder 1 could be optimized by strengthening pi-cation as well as electrostatic interactions. Electron-donating or -withdrawing substituents in the 5-position provide experimental evidence for pi-cation interactions, because binding energies increase by up to 0.6 kcal/mol due to a single benzene-guanidinium interaction. Even more effective is the introduction of a third phosphonate functionality at the correct distance, so that the guanidinium cation is recognized by optimal electrostatic and hydrogen bond interactions. Monte Carlo simulations and NOESY experiments confirm the expected complex geometries. The optimized host molecule 8 binds arginine half an order of magnitude more efficiently than the parent molecule.

Laparoscopic appendectomy in children with Enterobius vermicularis

As surgeons gain more experience with laparoscopy in children, it is becoming apparent that one of the best applications of the technique is for appendicitis. The advantages of laparoscopic appendectomy include a better cosmetic result, particularly in young female patients, a shorter recovery time, and an early return to normal activities. In the differential diagnosis of appendicitis, the association of Enterobius vermicularis (pinworms) inflammation in the pediatric age group is not uncommon. The endo-loop technique for laparoscopic appendectomy is the standard technique used in our department. In three patients with E. vermicularis undergoing appendix removal using this technique, pinworms were found to be set free into the abdomen after dividing the appendix between the loop ligatures. Bipolar coagulating forceps were used carefully to thermally desiccate the worms, which were then removed using a blunt grasper. E. vermicularis being released into the abdomen in children undergoing laparoscopic appendectomy using the endo-loop technique has not been reported. Careful evaluation of the appendix stump and simple but careful thermal desiccation and removal of pinworms, if present, must be considered when using the endo-loop technique.

Habitat use and habitat selection by spotted seals (Phoca largha) in the Bering Sea

Twelve spotted seals (Phoca largha) equipped with satellite-linked tags were tracked in the Bering Sea for 46-272 days during August-June 1991-1994. Alaskan seals were mostly near shore during August-October and 100-200 km offshore in January-June, and were broadly distributed in the region north of the 200-m isobath. Russian seals were located primarily near shore and within 100 km of the 200-m isobath during all months. During August-October, all seals were usually more than 200 km south of the sea-ice edge. In January-June, seals were mostly 0-200 km north of the sea-ice edge, often in areas with extensive ice coverage (7/10-9/10). We tested for habitat selection by determining how frequently a randomly moving seal would have been located in each habitat and comparing that with observed habitat use. Russian seals selected for nearshore and shallow-water areas in September-October and for near shore, within 25 km of the 200-m isobath, and the ice front during November-April. Alaskan seals selected for near shore areas in September-December; for offshore, shallow water, and the ice front in January-February; and for shallow water and pack ice in March-April. Biological processes associated with the highly productive "Green Belt" may have influenced the habitat use of Russian seals, but this did not appear to have been the case with Alaskan seals.

Executive control functions in task switching: evidence from brain injured patients

Executive mechanisms involved in task switching were studied in 18 brain injured patients. The patients had to rapidly switch back and forth between two visual classification tasks and the analyses focused on switch costs, (i.e., performance differences between switch and no-switch trials), and on interference effects, (i.e., processing costs imposed by the presence of interfering stimulus attributes). The patients were grouped according to the side of the brain lesion. Patients with left brain damage (LBD) showed higher switch costs than patients with right brain damage (RBD). These group differences were attributable to disproportionally high switch costs in patients with LBD and language or speech disorders. This result suggests that the efficiency of suppressing internal interference from a recently activated task set depends on the availability of verbal representations of the upcoming task. Patients with RBD showed higher interference from external task sets. This effect was not affected by language or speech disorders. The overall results argue for a fractionation of executive functions to protect against interference from internal and external sources in task switching.

Managed care as health care rationing

This article is based on the author's presentations to the New York State Governor's Health Care Advisory Board's Task Force on the President's Health Care Plan, November 22, 1993, and to a hearing of the New York State Attorney General on the experience of consumers with health insurers and health maintenance organizations, September 20, 1993. His comments deal with the effects of the Clinton health care reform proposal and other forms of managed care on those most in need of care. Particularly interesting are his suggestions for protecting the rights of health care consumers.

[Standards for treatment and expert opinion on transsexuals. The German Society for Sexual Research, The Academy of Sexual medicine and the Society for Sexual Science]

Over the last two-and-a-half years a committee of experts, consisting of members of the three leading German sexology associations, developed guidelines for treating and assessing transsexuals. Their purpose is to improve the care for patients with sex identity disorders and to ensure that such care is of uniform quality to avoid erroneous decisions to the disadvantage of those affected. The guidelines are set out in full.

Improvement of reversible ischemia in severe post-transplantation coronary artery disease

Coronary artery disease is a major cause of morbidity and mortality in patients who have undergone heart transplantation. Patients are often asymptomatic during the onset of the disease, and managing the disease is difficult. This report describes the case of a patient with post-transplantation coronary artery disease who, despite the severe, progressive appearance of the disease on angiographic examination, showed evidence of autorevascularization and collateralization.

Female perversion: scenes and strategies in analysis and culture

The author presents some ideas derived from observation in analysis about differing positions of Freud and Jung on perversion and about probable differences in perverse structural elements of women in contrast to men. In general perversion is understood as a defence of the self; in particular with women it is seen as a defensive way of achieving a false wholeness, a pseudo-androgyny. A case study describes the unfolding of a perverted transference. The importance of reaching the analyst and being understood by the analyst through projective identification is stressed. Quite often a sexually abusing mother seems to play an important role in generating female perversion; the implications in analysis are discussed as well as some ideas about culture and gender.