Performance of a static-anode/flat-panel x-ray fluoroscopy system in a diagnostic strength magnetic field: A truly hybrid x-ray/MR imaging system

Minimally invasive procedures are increasing in variety and frequency, facilitated by advances in imaging technology. Our hybrid imaging system (GE Apollo flat panel, custom Brand x-ray static anode x-ray tube, GE Lunar high-frequency power supply and 0.5 T Signa SP) provides both x-ray and MR imaging capability to guide complex procedures without requiring motion of the patient between two distant gantries. The performance of the x-ray tube in this closely integrated system was evaluated by modeling and measuring both the response of the filament to an externally applied field and the behavior of the electron beam for field strengths and geometries of interest. The performance of the detector was assessed by measuring the slanted-edge modulation transfer function (MTF) and when placed at zero field and at 0.5 T. Measured resonant frequencies of filaments can be approximated using a modified vibrating beam model, and were at frequencies well below the 25 kHz frequency of our generator for our filament geometry. The amplitude of vibration was not sufficient to cause shorting of the filament during operation within the magnetic field. A simple model of electrons in uniform electric and magnetic fields can be used to estimate the deflection of the electron beam on the anode for the fields of interest between 0.2 and 0.5 T. The MTF measured at the detector and the DQE showed no significant difference inside and outside of the magnetic field. With the proper modifications, an x-ray system can be fully integrated with a MR system, with minimal loss of image quality. Any x-ray tube can be assessed for compatibility when placed at a particular location within the field using the models. We have also concluded that a-Si electronics are robust against magnetic fields. Detailed knowledge of the x-ray system installation is required to provide estimates of system operation.

Studies into Using Manure in a Biorefinery Concept

Animal manure is an underutilized biomass resource containing a large amount of organic carbon that is often wasted with the existing manure disposal practices. A research project funded by the US Department of Energy explored the feasibility of using manure via the sugar platform in a biorefinery, converting the carbon from fiber to biochemicals. The results showed that (1) fiber was the major component of manure dry material making up approx 50%, 40%, and 36% of the dry dairy, swine, and poultry manure material, respectively; within dairy manure, more than 56% of the dry matter was in particles larger than 1.680 mm; (2) in addition to being a carbon source, manure could provide a variety of nutrient for fungi T. reesei and A. phoenicis to produce cellulase; (3) the hemicellulose component in the manure fiber could be readily converted to sugar through acid hydrolysis; while concentrated acid decrystallization treatment was most effective in manure cellulose hydrolysis; (4) purification and separation was necessary for further chemical conversion of the manure hydrolysate to polyols through hydrogenation; and (5) the manure utilization strategy studied in this work is currently not profitable.

First use of a truly-hybrid X-ray/MR imaging system for guidance of brain biopsy

The use of a new hybrid imaging system for guidance of a brain biopsy is described. The system combines the strengths of MRI (soft-tissue contrast, arbitrary plane selection) with those of x-ray fluoroscopy (high-resolution real-time projection images, clear portrayal of bony structures) and allows switching between the imaging modalities without moving the patient. The biopsy was carried out using x-ray guidance for direction of the needle through the foramen ovale and MR guidance to target the soft-tissue lesion. Appropriate samples were acquired. The system could be particularly effective for guidance of those cases where motion, swelling, resection and other intra-operative anatomical changes cannot be accounted for using traditional stereotactic-based imaging approaches.

Effect of 60Co irradiation on characteristics of hemorheology in rabbits

A high-dose (7 Gy) whole-body 60Co irradiation for a short period caused disturbances of hematopoietic function. A decrease in the hematocrit of the circulating blood lasted for about 15 days, thus forming an anemic animal model. We studied the influence of high-dose 60Co irradiation on hemorheologic parameters: percentage of reticulocytes, RBC deformability, sedimentation rate and plasma fibrinogen concentration in the rabbit. It was found that the plasma fibrinogen concentration increased to twice more than control level and that percentage of reticulocytes in circulation disappeared immediately after irradiation. The deformation index of RBCs in shear flow decreased from a value of 58% down to a value of 42% in the first two weeks and gradually returned to control levels about 40 days after 60Co irradiation. Our results showed that a short period of high-dose 60Co irradiation caused severe and relatively long-lasting damage of hematopoietic system in animals' body.

Morphologic transformation of the thymus in developing zebrafish

The morphologic transformation of the developing zebrafish thymus from 1 week postfertilization (wpf) to 15 wpf is described. The thymus overall morphology changed from a small pouch-like shape at 1 wpf to a conical shape between 2 and 3 wpf before acquiring a more complex shape from 4 wpf onward. Rapid growth rate along the lateral axis at the region near the pharyngeal epithelium occurred between 1 and 2 wpf, whereas rapid growth rate along the dorsal-ventral axis occurred between 3 and 6 wpf. Expansion of thymocyte population beginning from 1 wpf became more evident by 2 to 3 wpf, as indicated by the apparent increase of different sizes of lymphocytes, recombination activating gene-1 (rag-1), and T-cell antigen receptor alpha chain constant region (TCRAC) -positive cells. Tissue section in situ hybridization (ISH) analysis with rag-1 probe reveals that cortex-medullary regionalization has begun between 1 and 2 wpf as rag-1 expression clearly demarcated the cortex, whereas the medulla was rag-1 negative. The presence of TCRAC-positive cells in the medulla by 2-3 wpf, suggests that the thymic selection processes had begun. The zebrafish thymus is morphologically mature by 3 wpf. Early signs of thymic involution were observed in zebrafish aged 15 wpf.

China's water environment at the beginning of the 21st century: challenges and countermeasures

Water environment crisis is a common challenge throughout the world, and the situation is becoming worse. This paper analyzes the development trend of water environment worldwide, and then evaluates the status of China's water environment and the progress in the work of protection of the water environment. According to the future development of economy and society in China, the paper discusses the severe challenges in water environment that China faces at the beginning of the 21st century and proposes related countermeasures.

Truly hybrid interventional MR/X-ray system: investigation of in vivo applications

RATIONALE AND OBJECTIVES

The purpose of this study was to provide in vivo demonstrations of the functionality of a truly hybrid interventional x-ray/magnetic resonance (MR) system.

MATERIALS AND METHODS

A digital flat-panel x-ray system (1,024(2) array of 200 microm pixels, 30 frames per second) was integrated into an interventional 0.5-T magnet. The hybrid system is capable of MR and x-ray imaging of the same field of view without patient movement. Two intravascular procedures were performed in a 22-kg porcine model: placement of a transjugular intrahepatic portosystemic shunt (TIPS) (x-ray-guided catheterization of the hepatic vein, MR fluoroscopy-guided portal puncture, and x-ray-guided stent placement) and mock chemoembolization (x-ray-guided subselective catheterization of a renal artery branch and MR evaluation of perfused volume).

RESULTS

The resolution and frame rate of the x-ray fluoroscopy images were sufficient to visualize and place devices, including nitinol guidewires (0.016-0.035-inch diameter) and stents and a 2.3-F catheter. Fifth-order branches of the renal artery could be seen. The quality of both real-time (3.5 frames per second) and standard MR images was not affected by the x-ray system. During MR-guided TIPS placement, the trocar and the portal vein could be easily visualized, allowing successful puncture from hepatic to portal vein.

CONCLUSION

Switching back and forth between x-ray and MR imaging modalities without requiring movement of the patient was demonstrated. The integrated nature of the system could be especially beneficial when x-ray and MR image guidance are used iteratively.

[A summary description of development in immunosensor]

In this review, an introduction to the concept and fundamental principles of immunosensor is given, and immunosensor is classified into many types according to the difference of transducers, each type being compared with others and explicated in derivation and developing process respectively. Two problems about the fabrication of immunosensor, which are immobilization and reproductivity, are addressed fleetly. In addition, the application and developing tendency of immunosensor are described briefly.

Low viscosity Ektacytometry and its validation tested by flow chamber

The flow chamber was used to observe the orientation and small deformation of red blood cells (RBCs) in a shear flow of low viscosity. With the aid of computer software, the percentage of RBCs oriented to the C=0 orbit (OI)(F) and the degree of deformation (DI)(F) of such RBCs were calculated by processing the photographs. It was found that these parameters were highly correlated, respectively, to the orientation index (OI)(E) and the small deformation index (DI)(E) obtained by our low viscosity Ektacytometry (LVE). Thus, our flow chamber research has provided direct evidence to validate the use of this low viscosity Ektacytometry. Although there are relative merits for the flow chamber method using low viscosity medium, the LVE is more likely to be applied in clinic for its simplicity and convenience.

Cytochromes P450 of insects: the tip of the iceberg

The cytochrome P450-dependent monooxygenases are an extremely important metabolic system involved in the metabolism of endogenous compounds and xenobiotics. Collectively, P450 monooxygenases can metabolize numerous substrates and carry out multiple oxidative reactions. The large number of substrates metabolized is due to the plethora of P450 isoforms and to the broad substrate specificity of some isoforms. Monooxygenases of insects have several functional roles, including growth, development, feeding and protection against xenobiotics, including resistance to pesticides and tolerance to plant toxins. This review begins with background information about P450s and their evolution, followed by a discussion of the extraordinary diversity of insect P450s. Given the enormous interest in studying individual P450s, we then provide a synopsis of the different methods that have been used in their isolation and the substrates that are known to be metabolized. We conclude by summarizing the lessons we have learned from the study of individual insect P450s, including their roles in insecticide resistance, plant-insect interactions and insect physiology. However, these studies are just the 'tip of the iceberg'. Our knowledge continues to expand at a rapid pace, suggesting that the next decade will outpace the last in terms of improving our understanding of the cytochromes P450 of insects.

Fluorophore-labeled S-nitrosothiols

A series of fluorophore-labeled S-nitrosothiols were synthesized, and their fluorescence enhancements upon removal of the nitroso (NO) group were evaluated either by transnitrosation or by photolysis. It was shown that, with a suitable alkyl linker, the fluorescence intensity of dansyl-labeled S-nitrosothiols could be enhanced up to 30-fold. The observed fluorescence enhancement was attributed to the intramolecular energy transfer from fluorophore to the SNO moiety. Ab initio density functional theory (DFT) calculations indicated that the "overlap" between the SNO moiety and the dansyl ring is favored because of their stabilizing interaction, which was in turn affected by both the length of the alkyl linker and the rigidity of the sulfonamide unit. In addition, one of the dansyl-labeled S-nitrosothiols was used to explore the kinetics of S-nitrosothiol/thiol transnitrosation and was evaluated as a fluorescence probe of S-nitrosothiol-bound NO transfer in human umbilical vein endothelial cells.

Photoaffinity labeling of insect nicotinic acetylcholine receptors with a novel [(3)H]azidoneonicotinoid

The nicotinic acetylcholine receptor (nAChR) is a ligand-gated ion channel in the insect CNS and a target for major insecticides. Here we use photoaffinity labeling to approach the functional architecture of insect nAChRs. Two candidate 5-azido-6-chloropyridin-3-yl photoaffinity probes are evaluated for their receptor potencies: azidoneonicotinoid (AzNN) with an acyclic nitroguanidine moiety; azidodehydrothiacloprid. Compared to their non-azido parents, both probes are of decreased potencies at Drosophila (fruit fly) and Musca (housefly) receptors but AzNN retains full potency at the Myzus (aphid) receptor. [(3)H]AzNN was therefore radiosynthesized at high specific activity (84 Ci/mmol) as a novel photoaffinity probe. [(3)H]AzNN binds to a single high-affinity site in Myzus that is competitively inhibited by imidacloprid and nicotine and further characterized as to its pharmacological profile with various nicotinic ligands. [(3)H]AzNN photoaffinity labeling of Myzus and Homalodisca (leafhopper) detects a single radiolabeled peak in each case displaceable with imidacloprid and nicotine and with molecular masses corresponding to approximately 45 and approximately 56 kDa, respectively. The photoaffinity-labeled receptor in both Drosophila and Musca has imidacloprid- and nicotine-sensitive profiles and migrates at approximately 66 kDa. These photoaffinity-labeled polypeptides are considered to be the insecticide-binding subunits of native insect nAChRs.

Two-component molecular crystals from N-heteroaromatics and nitrobenzoic acids

Five two-component molecular crystals, benzimidazolium 3-nitrobenzoate, C(7)H(7)N(2)(+).C(7)H(4)NO(4)(-), (I), benzimidazolium 4-nitrobenzoate, C(7)H(7)N(2)(+).C(7)H(4)NO(4)(-), (II), 1H-benzotriazole-3-nitrobenzoic acid (1/1), C(6)H(5)N(3).C(7)H(5)NO(4), (III), imidazolium 3-nitrobenzoate, C(3)H(5)N(2)(+).C(7)H(4)NO(4)(-), (IV), and imidazolium 4-nitrobenzoate, C(3)H(5)N(2)(+).C(7)H(4)NO(4)(-), (V), were prepared with the aim of making chiral crystals. Only (I) crystallizes in a chiral space group. The molecules of (I) and (II) are linked by hydrogen bonds to form 2(1) spiral chains. In (III), (IV) and (V), macrocyclic structures are formed from two acid and two base components, by an alternate arrangement of the acid and base moieties.

CYP9E2, CYP4C21 and related pseudogenes from German cockroaches, Blattella germanica: implications for molecular evolution, expression studies and nomenclature of P450s

The cDNAs of two novel P450s (CYP9E2 and CYP4C21) were isolated from German cockroaches, Blattella germanica. Both CYP9E2 and CYP4C21 are typical microsomal P450s and their deduced amino acid sequences share a number of common characteristics with other members of the P450 superfamily. Northern blot analyses using a CYP9E2 or CYP4C21 probe showed that 'CYP9E2' and 'CYP4C21' were expressed at all life stages. Two pseudogenes related to CYP9E2 and three pseudogenes related to CYP4C21 were also isolated. These represent the first P450 pseudogenes from an insect other than Drosophila melanogaster. The relative number of P450 pseudogenes in B. germanica is apparently higher than in D. melanogaster. The implications of these results for the molecular evolution, expression studies and nomenclature of P450s are discussed.

[Effects of the alterations of membrane shear elastic modulus and viscosity on the deformation and orientation of RBCs]

Neuraminidase can partly remove the surface charge of RBCs through a biochemical interaction; thus it can give rise to alterations in the microstructure of membrane, the shear elastic modulus (E) and the viscosity(micron) of membrane. Changing the time of treatment and the dose of neuraminidase and using a new ektacytometry that can separate deformation index DI into orientation index (DI)or and small deformation index (DI)d for RBCs in shear flow field of low viscosity, we measured (DI)d and the half time t0.5 when the DI recovered to half of the maximum in the process of relaxation for every treated sample. (DI)d and t0.5 were put respectively into the RBC membrane shear elastic modulus formula and the membrane viscosity formula which were put forward by Wen Zong-yao and Yan Zong-yi et al[1]. The rules of the alterations of E and micron were obtained. We also measured DI and (DI)or. It was found that E and micron increased greatly but DI and (DI)or decreased when the dose of neuraminidase and the time of treatment were increased. There was a contrary correlation between them. These data demonstrated that the increase of E and micron weakened the deformability and the ability of orientation of RBCs.

[Association between apolipoprotein E polymorphism and Alzheimer's disease: A population-based study in Guangzhou, China]

OBJECTIVE

To investigate the distribution of apolipoprotein E (apoE) genotype of patients with Alzheimer's disease (AD) in the population aged 75 and older in Guangzhou and to determine whether there was an association between AD and apoE epsilon4 allele.

METHODS

A systematic cluster sampling design, two-stage screening and field evaluations were used in a cross-sectional population-based study. Three thousand eight handred and twenty-five subjects aged 75 and above in Liwan district of Guangzhou were interviewed. Blood samples were collected from 110 cases and 518 normal controls. The criteria of DSM-III-R and NINCDS-ADRDA were used for clinical diagnosis of probable AD. Polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) were used to determine apoE genotypes.

RESULTS

There were 190 cases diagnosed as sporadic AD from this sample. The frequencies of the three apoE alleles were detected as follows: epsilon2 = 0.100, epsilon3 = 0.832, epsilon4 = 0.068 in AD patients; epsilon2 = 0.092, epsilon3 = 0.843, epsilon4 = 0.065 in normal controls. The frequencies of apoE genotype and allele in the AD patients were not significantly different from that in normal subjects (P > 0.05).

CONCLUSION

No association between sporadic AD and apoE epsilon4 allele was found among the population aged 75 and above in Liwan district of Guangzhou.

[Effect of radiation with 60Co on RBC membrane elastic shear modulus and membrane viscosity]

RBC membrane shear elastic modulus and membrane viscosity are two important indexes reflecting RBC membrane viscoelasticity. Their variation was investigated in this study after rabbits were radiated with 60Co. With a new ektacytometer, we measured the small deformation index (DId) and the half-time of deformation relaxation (t0.5) of RBC in flow field then we calculated RBC membrane shear elastic modulus and membrane viscosity. We found that the value of RBC membrane shear elastic modulus and membrane viscosity continuously increased from 0 to 16th day then continuously decreased and tended to be stable on 60th day or so. The reason may lie in the variation of proportion of new and old RBC in blood and variation of microconformation of RBC membrane after rabbits were radiated with 60Co.

Effects of olfactory bulbectomy on NMDA receptor density in the rat brain:

Olfactory bulbectomy (OBX) transects the glutamatergic efferents from the olfactory bulbs, and the changes of glutamatergic N-methyl-D-aspartate (NMDA) receptor-mediated function are though to be involved in the behavioral deficits seen in OBX rats. In the present study, irritability scores in OBX male Wistar rats were correlated with discrete regional effects on NMDA receptor function measured using a [3H] MK-801 binding assay. Irritability scores, measured before and for 2 weeks after OBX, showed a gradual increase in irritability after OBX. A reduction of the NMDA receptor density was observed in the cerebral cortex and amygdala 16 days after OBX, but not in the striatum, olfactory tubercle, entorhinal cortex, and hippocampus. These results demonstrate that OBX causes changes in the NMDA receptor system in certain brain regions and suggest that these changes may be responsible for the behavioral deficits of OBX rats.

Influence of neuraminidase on the characteristics of microrheology of red blood cells

Surface charge was removed from RBC (erythrocyte) membrane to different degrees with biochemical methods, i.e., treatment of RBCs with neuraminidase, either using different doses for the same incubation time (1 hour) or using the same dose (75 milli-unit) for different incubation time. Several rheological properties of the RBCs with surface charge removal were observed, including the deformation index DI (using traditional ektacytometry) orientation index (DI)or and small deformation index (Dl)d (using new ektacytometry), the viscosity at low and high shear rates (using a cone-plate rotating viscosimeter). In addition, photographs of RBCs aggregation under a microscope and the histograms of RBC aggregate size after treatment with neuraminidase were obtained. It is found from these experiments that the decrease of the surface charge of RBCs leads to the decrease in the deformation and orientation indices as well as the increase in blood viscosity.

Cloning of two novel P450 cDNAs from German cockroaches, Blattella germanica (L.): CYP6K1 and CYP6J1

Two novel P450 cDNAs, CYP6K1 and CYP6J1, were isolated from German cockroaches, Blattella germanica (L). Both CYP6K1 and CYP6J1 are typical microsomal P450s and their deduced amino acid sequences share a number of common characteristics with other members of the P450 superfamily. Both CYP6K1 and CYP6J1 showed the highest per cent identity (based on the deduced amino acid sequence) to CYP6L1 from B. germanica and CYP6H1, a putative ecdysone 20-hydroxylase from Locusta migratoria. Using a CYP6K1 probe, two mRNA signals (~2.5 and ~2.1 kb) were detected in all life stages. Both signals were just detectable in the eggs and became stronger in later instars. The strongest signals were detected in the fifth and sixth instars as well as in adults. These two bands were also detected in the abdomens and in the remainder of bodies of both male and female adults. Southern blots suggest the two mRNA bands detected in the Northern blot might be a result of alternative splicing. No signal could be detected at any life stage using the CYP6J1 probe, suggesting that CYP6J1 was expressed at a low level.