Optimization of multidrug resistance 1 gene transfer confers chemoprotection to human hematopoietic cells engrafted in immunodeficient mice

OBJECTIVE

To investigate whether an optimization of MDR1 gene transfer protocol would result in stable hematopoietic stem cell (HSC) engraftment and myeloprotection in non-obese diabetic/severe combined immunodeficient (NOD/SCID) mice after paclitaxel chemotherapy.

METHODS

We transplanted freshly isolated CD34+ cells or MDR1-transduced CD34+ cells derived from human umbilical cord blood (UCB) into sublethally irradiated NOD/SCID mice. Twenty-eight days after transplantation, mice received paclitaxel chemotherapy and peripheral blood (PB) was collected for analysis of WBC, RBC and PLT counts once every week.

RESULTS

We found that MDR1-transduced human hematopoietic cells could facilitate hematopoietic recovery and completely reconstitute hematopoiesis in mice as well as freshly isolated CD34+ cells. Mice transplanted with MDR1-transduced human hematopoietic cells were protected from paclitaxel chemotherapy with higher survival rate and higher level of WBC counts and RBC counts compared with mice transplanted with untransduced HSCs. We also demonstrated that hematopoietic cells transduced with MDR1 gene were enriched in vivo after paclitaxel chemotherapy determined by the higher percentage of human Rh-123(dull) CD45+ cells in bone marrow of mice.

CONCLUSION

Our results demonstrated successful chemoprotection against myelosuppression in mice by MDR1-transduced repopulating human hematopoietic cells with an optimized transduction protocol.

The AFT024 stromal cell line improves MDR1 gene transfer to CD34+ cells derived from human umbilical cord blood

Human hematopoietic stem cells (HSCs) are difficult to transfect with retroviral vectors because of their quiescent nature. Based on the theory that the murine fetal stromal cell line AFT024 can recruit significant numbers of HSC into cell cycle without loss of their primitive function, we transduced human umbilical cord blood cells (UCB) derived CD34+ cells with a retroviral vector pHaMDR1/A containing the human multidrug resistant 1 gene (MDR1) during co-culture with the AFT024 feeders. We found that the presence of the AFT024 cells increased the proportion of Rh-123dull cells up to 35.5%+/-11.4% and transduced colony-forming cells (CFCs) up to 15.2%. Six weeks after transplantation of 5x10(4) day 0 uncultured CD34+ HSCs or their equivalents expanded in the presence or absence of the AFT024 cells for 21 days into non-obese diabetic/severe combined immunodeficient (NOD/SCID) mice, we found that CD34+ cells expanded in the presence of the AFT024 cells engrafted in each receptor mouse and the percentage of CD45+ cells reached 18.8%+/-9.5%, of which 18.1%+/-6.0% were Rh-123dull cells. These results suggest that the AFT024 stromal cells can significantly improve MDR1 gene transfer efficiency and maintain the engrafting ability of the CD34+ HSCs derived from UCB.

Mature data on capecitabine (X) + fractionated cisplatin (P) as first-line therapy in patients (pts) with advanced gastric carcinoma (AGC)

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Background: Gastric cancer is one of the most common malignancies in Asia with an adjusted mortality rate above 20/100,000 population. 5-FU + fractionated P is a standard treatment for AGC in China. In a Korean study by Kim et al., X + P produced a response rate of 55% in pts with previously untreated AGC. Here we present mature efficacy/safety results in Chinese pts with AGC. Methods: 154 pts of a planned population of 120 pts were enrolled between Jun 2002 and Aug 2004. All had measurable AGC (WHO), Karnofsky performance status ≥60, adequate bone marrow, renal and hepatic functions. Prior radiotherapy or adjuvant chemotherapy was permitted. Pts received × 1000 mg/m2 orally bid on days 1–14 + P 20mg/m2/day i.v. on days 1–5, every 3 weeks for 6 cycles. The primary endpoint was time to disease progression (TTP). Results: Baseline characteristics of the 141 evaluable pts (104 men, 37 women) are: median age 54 years (range 23–80), main sites of metastases: lymph nodes 45%, liver 40%, stomach 18%, skin 6%, other 6%, lung 5%, abdomen 4%. The overall response rate was 36%, including 13 complete responses and 38 partial responses. After a median follow-up period of 12 months, the median TTP is 9 months (95% CI, 9–12 months) and the median overall survival is 12 months (95% CI, 12–15 months). Median treatment duration was 6 cycles (range 3–6). The most common treatment-related clinical adverse events (all grades >5%) were: hand-foot syndrome (HFS) 25%, leucopenia 13%, and SGOT abnormality 12%. The most commongrade 3 adverse events were SGPT abnormality 3%, HFS 2%, and anemia 2%. There were no grade 4 adverse events. Most grade 3 adverse events improved or resolved after treatment or interruption except in 1 pt with anemia who withdrew after 2 cycles. Conclusions: X combined with fractionated P is highly active and very well tolerated as first-line treatment for AGC, with comparable results to 5-FU + P.

No significant financial relationships to disclose.

Classifying G protein-coupled receptors and nuclear receptors on the basis of protein power spectrum from fast Fourier transform

As the potential drug targets, G-protein coupled receptors (GPCRs) and nuclear receptors (NRs) are the focuses in pharmaceutical research. It is of great practical significance to develop an automated and reliable method to facilitate the identification of novel receptors. In this study, a method of fast Fourier transform-based support vector machine was proposed to classify GPCRs and NRs from the hydrophobicity of proteins. The models for all the GPCR families and NR subfamilies were trained and validated using jackknife test and the results thus obtained are quite promising. Meanwhile, the performance of the method was evaluated on GPCR and NR independent datasets with good performance. The good results indicate the applicability of the method. Two web servers implementing the prediction are available at http://chem.scu.edu.cn/blast/Pred-GPCR and http://chem.scu.edu.cn/blast/Pred-NR.

Delaunay triangulation with partial least squares projection to latent structures: a model for G-protein coupled receptors classification and fast structure recognition

As an important transmembrane protein family in eukaryon, G-protein coupled receptors (GPCRs) play a significant role in cellular signal transduction and are important targets for drug design. However, it is very difficult to resolve their tertiary structure by X-ray crystallography. In this study, we have developed a Delaunay model, which constructs a series of simplexes with latent variables to classify the families of GPCRs and projects unknown sequences to principle component space (PC-space) to predict their topology. Computational results show that, for the classification of GPCRs, the method achieves the accuracy of 91.0 and 87.6% for Class A, more than 80% for the other three classes in differentiating GPCRs from non-GPCRs and 70% for discriminating between four major classes of GPCR, respectively. When recognizing the structure of GPCRs, all the N-terminals of sequences can be determined correctly. The maximum accuracy of predicting transmembrane segments is achieved in the 7th transmembrane segment of Rhodopsin, which is 99.4%, and the average error is 2.1 amino acids, which is the lowest in all of the segments prediction. This method could provide structural information of a novel GPCR as a tool for experiments and other algorithms of structure prediction of GPCRs. Academic users should send their request for the MATLAB program for classifying GPCRs and predicting the topology of them at liml@scu.edu.cn .

137Cs budget during the period of 1960s in a small drainage basin on the Loess Plateau of China

A sediment profile with a thickness of 28.12 m in a failed reservoir in a small catchment of the Yuntaishan Gully in the Loess Plateau of China consisted of 44 flood couplets deposited during the period from 1960 to 1970 with total volume of 2.36 x 10(6)m(3). Specific sediment yields for a flood event varied from 300 t km(-2) to 14,400 t km(-2) and annual sediment yields varied from 2500 t km(-2) in 1966 to 40,000 t km(-2) in 1964 with a mean value of 12,700 t km(-2)a(-1) for the period. Average annual (137)Cs concentrations of the sediments increased from 0.92 Bq kg(-1) in 1960 to 4.82 Bq kg(-1) in 1963, then decreased to 1.53 Bq kg(-1) in 1970. The total (137)Cs activity in the reservoir sediments was 9.22 x 10(9) Bq, which accounted for 31.9% of the total (137)Cs fallout precipitation of 2.89 x 10(10) Bq within the catchment during the period. The proportion of the (137)Cs loss from the catchment to the (137)Cs fallout precipitation within the catchment in a year varied between 8.01% and 66.8%, and it was 20.9% for the peak (137)Cs deposition year of 1963 and 52.0% in 1964. By analysis of the (137)Cs budget in the catchment for the (137)Cs peak precipitation period from 1962 to 1964, the (137)Cs surface enrichment coefficient Gamma should be much less than 0.23. And for calculation of soil losses on the cultivated land in the inter-gully area by using the Mass Balance Model II, the value of Gamma should be 0.05-0.1.

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.

A study of hemorheological behaviour for patients with Alzheimer's disease at the early stages

To evaluate the change of hemorheological indexes for patients with Alzheimer's disease (AD) at the early stages and to discuss effects of these changes on AD, high shear value of whole blood viscosity (etabh), reduced high shear value of whole blood viscosity (retabh), low shear value of whole blood viscosity (etabl), reduced low shear, value of whole blood viscosity (retabl), KT value of whole blood viscosity, hematocrit (HCT) and blood plasma viscosity (etaP) were measured in 31 patients with probable AD at the early stages and 33 age-matched healthy subjects. There were significant differences of all hemorheological indexes between AD group and control group except HCT. Step discriminant analysis revealed 81.25% of overall group-classified accuracy in a hemorheological discriminant function consisting of etabl, retabl, retabh and HCT. Significant difference of hemorheological indexes existed between AD and age-matched healthy control subjects. The results showed that measurement of hemorheological indexes could be used as one of reference standards of diagnosis in AD.

On the direction and magnitude of radical substituent effects: the role of polar interaction on thermodynamic stabilities of benzylic C-H bonds and related carbon radicals

The C-H bond dissociation enthalpies (BDEs) of polarized benzylic molecules, i.e., para-substituted phenylacetonitriles (PANs), and the spin variations of the radicals of the general type p-GC6H4CH*-Y were investigated using density functional theory (DFT) calculations. In contrast to the commonly observed S-type substituent effect (see text), the present work shows that there should be three (rather than one) primary patterns (i.e., S, O, and counter-O) for remote G to affect spin and radical stability, depending upon the polarity of the alpha-Y group. Correlation analyses reveal that both the direction and magnitude of spin/radical effects are quantitatively related to the intensity of polar interaction in radical system, as registered by either the calculated group charges of the phenyl ring (C(Ph)) or by the polar constant sigma(+)s (Figures 1-4). A unified platform (Scheme 1) to rationalize the apparent differences of radical substituent effect is proposed.

Equilibrium and kinetics studies of transnitrosation between S-nitrosothiols and thiols

Using UV-vis spectrometrical measurements, equilibrium constants for NO transfer between S-nitroso-N-acetyl-penicillamine (SNAP) and different thiols as well as kinetic data for NO transfer from S-nitroso bovine serum albumin (BSANO) to thiols have been obtained. NO transfer from SNAP to other primary/secondary thiols are thermodynamically favorable, whereas other S-nitrosothiols exhibit similar NO transfer potential. The obtained Gibbs free energy, enthalpy and entropy data indicated that NO transfer reactions from SNAP to four thiols are exothermic with entropy loss. The kinetic behavior of BSANO/RSH transfer can be related to both the acidity of sulfhydryl group and the electronic structure in thiol.

Cytochrome P450 CYP6L1 is specifically expressed in the reproductive tissues of adult male German cockroaches, Blattella germanica (L.)

A full-length cDNA encoding a new cytochrome P450, CYP6L1, was cloned from German cockroaches, Blattella germanica. CYP6L1 has an open reading frame of 1509 nucleotides with a deduced protein of 503 amino acids and molecular mass of 57 Kd. CYP6L1 is most similar to CYP6H1, a putative ecdysone 20-hydroxylase from Locusta migratoria. CYP6L1 mRNA was not detected in embryos nor nymphs, nor in adult females. CYP6L1 mRNA was detected only in the testes and accessory glands of male adult German cockroaches. Given that the testes and accessory glands are the most important components of the reproductive system in male insects, the expression of CYP6L1 mRNA exclusively in these tissues strongly suggests that CYP6L1 has a role in reproduction. Possible substrates for CYP6L1 are discussed.

A truly hybrid interventional MR/X-ray system: feasibility demonstration

A system enabling both x-ray fluoroscopy and MRI in a single exam, without requiring patient repositioning, would be a powerful tool for image-guided interventions. We studied the technical issues related to acquisition of x-ray images inside an open MRI system (GE Signa SP). The system includes a flat-panel x-ray detector (GE Medical Systems) placed under the patient bed, a fixed-anode x-ray tube overhead with the anode-cathode axis aligned with the main magnetic field and a high-frequency x-ray generator (Lunar Corp.). New challenges investigated related to: 1) deflection and defocusing of the electron beam of the x-ray tube; 2) proper functioning of the flat panel; 3) effects on B0 field homogeneity; and 4) additional RF noise in the MR images. We have acquired high-quality x-ray and MR images without repositioning the object using our hybrid system, which demonstrates the feasibility of this new configuration. Further work is required to ensure that the highest possible image quality is achieved with both MR and x-ray modalities.

[Preliminary clinical comparison of HLF and ELF regimen in the treatment of advanced gastric carcinoma in middle-aged and elderly patients]

OBJECTIVE

To observe the therapeutic effects and toxicity of HLF (hydroxycamptothecin HCPT/leucovorin LV/fluorouracil 5-Fu) regimen and ELF (etoposide VP-16/LV/5-Fu) regimen in middle-aged and elderly patients with advanced gastric carcinoma.

METHODS

A group of twenty-five cases were treated with HLF regimen, and the other group of 23 cases were treated with ELF regimen.

RESULTS

Of the 25 cases treated with HLF regimen, there was no complete remission (CR), but there were 12 partial response (PR), 11 no response (NC), and 2 had progressive disease (PD). The response rate (RR) was 48.0%. Of the 23 patients treated with ELF regimen, there was no CR, there were 9 PR, 11 NC, and 3 PD. The RR was 39.1% (P > 0.05). The main toxicity was myelosuppression and stomatocace. Grade III-IV stomatocace in HLF regimen group (68.0%) was more commonly seen than that in ELF regimen group (39.1%, P < 0.05). There was no cardiac or renal toxicity observed.

CONCLUSION

HLF regimen is promising for treatment of advanced gastric carcinoma in middle-aged and elderly patients with the merits of low toxicity affecting heart, kidney and bladder except stomatocace, which is worthy of further clinical trial.

[Expression of telomerase and its RNA in nasopharyngeal carcinoma]

OBJECTIVE

To study the activity of telomerase and the expression of its RNA in nasopharyneal carcinoma (NPC) and HNE1 cell lines of NPC.

METHODS

Telomerase activity was detected with telomeric repeat amplification protocol (TRAP) PCR ELISA kit in 41 cases of NPC, 14 cases of tissues adjacent to the carcinoma, and 19 cases of chronic nasopharyngitis, HNE1 cell lines of NPC, HL60 cell lines of leukemia, TUL1 cell lines of lung cancer, as well as three other kinds of normal control cells. The sensitivity and specificity of telomerase assay were also analyzed. Moreover, the expression of human telomerase RNA (hTR) was studied in 27 cases of NPC, 19 cases of adjacent nasopharyngeal tissues, and 17 cases of control groups by RT-nested PCR.

RESULTS

The telomerase activity was found increased in NPC and in tissues adjacent to NPC with absorbance value (A value) of 1.15 U +/- 0.78 U and 1.04 U +/- 0.67 U respectively, compared with chronic nasopharyngitis (A = 0.18 U +/- 0.09 U). In NPC with cervical lymphnodes involvement the telomerase activity (A = 1.25 U +/- 0.79 U) was higher than in those without involvement (A = 1.02 U +/- 0.71 U), P < 0.05. The telomerase activity was also observed in HNE1 cell lines (A = 1.26 U +/- 0.97 U) and in other two kinds of cancer cell lines, but not in the three kinds of normal control cells. By contrast, no significant difference was seen in the expression of hTR among the three nasopharyngeal biopsy groups (P > 0.05). Finally, the sensitivity of telomerase assay was high (at an amount of 10(2) HNE1 cells), and the specificity was also high (after inactivation by heat or RNase, the telomerase activity was very low).

CONCLUSIONS

A high frequency of telomerase activity is commonly seen in NPC, adjacent nasopharyngeal tissues, and HNE1 cell lines and is closely associated with NPC with cervical lymphnodes involvement. Both sensitivity and specificity of the telomerase assay are high. However, owing to the fact that the expression of hTR has no obvious difference between NPC and normal tissues and does not always correspond with the telomerase activity, it would be better to do TRAP as well as hTR assays for the activity and expression in assessing the carcinogenesis of NPC. So, more intensive study on the role of hTR in the carcinogenesis of NPC and on the exact relationship between hTR and telomerase is needed.

Pleural lavage cytology in esophageal cancer without pleural effusions: clinicopathologic analysis

OBJECTIVE

The literature of pleural lavage cytology (PLC) is focused on lung cancer. We conducted this pilot study to determine the incidence of malignant pleural cytologies in patients without pleural effusions who undergo curative resection for esophageal cancer, and to evaluate the clinicopathologic significance of positive cytology.

METHODS

Forty-eight patients underwent esophagectomy for thoracic esophageal cancer in our unit from January 1998 to January 1999. After thoracotomy, pleural lavage was performed before any intrathoracic manipulation and cytologically evaluated.

RESULTS

There was one patient with stage I, 27 patients with stage II, and 20 patients with stage III cancer of the thoracic esophagus. The mean age was 55 years (range 41-77 years). Fifteen cases (31.3%) were found to have positive lymph nodes (N1). Squamous cell carcinoma was the dominant histopathologic type (91.7%). Positive lavage cytology in the whole group was found in 18.8% (9/48). There was no significant correlation to gender, age, clinical symptoms, histology, T or N status, TNM stage, or tumor location.

CONCLUSIONS

The incidence of positive pleural lavage cytology in esophageal cancer is disconcertingly high. Positive cytology might suggest a more aggressive tumor biology. Future studies on its relation to survival and occult lymphatic metastasis are warranted.

Expression of apoptosis-associated genes by human dermal scar fibroblasts

The purpose of this study was to determine if aberrant apoptosis plays a role in pathologic wound healing as manifested by hypertrophic scarring and keloid formation. Apoptosis has recently been found to participate in the transition between granulation tissue and the development of definitive scar. The question that remains to be answered is what stimuli initiate apoptosis during wound healing. Hitherto, regulatory factors and pathways involved have been largely undefined. We investigated heterogeneity among fibroblasts derived from normal skin and keloid scar, by examining apoptotic profiles and pathways for these cells. Quantitative analysis of apoptotic cells using an Annexin-V-FITC binding assay showed that normal skin fibroblast cultures were found to have a two-fold higher percentage of apoptotic cells than did keloid fibroblast cultures. To study apoptotic pathways and related death-associated genes, a ribonuclease protection assay was performed for fibroblasts exposed to anti-Fas antibody and tumor necrosis factor-alpha to activate the Fas/TNF receptor apoptotic pathway. Compared with normal skin fibroblasts, keloid fibroblasts exhibited decreased expression of apoptosis-associated genes.

The linker domain of Stat1 is required for gamma interferon-driven transcription

Upon binding of gamma interferon (IFN-gamma) to its receptor, the latent transcription factor Stat1 becomes phosphorylated, dimerizes, and enters the nucleus to activate transcription. In response to IFN-alpha, Stat1 binds to Stat2 in a heterodimer that recruits p48, an IRF family member, to activate transcription. A number of functional domains of the STATs, including a C-terminal transactivation domain, a dimerization domain, and an SH2 domain, are known. However, the highly conserved residues between the DNA binding and SH2 domains (463 to 566), recently christened the linker domain on the basis of crystallographic studies, have remained without a known function. In the present study, we report that KE544-545AA point mutants in Stat1 abolish transcriptional responses to IFN-gamma but not to IFN-alpha. We further show that this mutant Stat1 undergoes normal phosphorylation, nuclear translocation, and DNA binding. Taken together with recent structural evidence, these results suggest that the linker domain acts as a critical contact point during the construction of a Stat1-driven transcriptional complex.

Regulatory roles of IL-12, IL-4 and IFN-gamma on IgE synthesis in atopic patients

OBJECTIVE

To investigate the mechanism of cytokine regulation in atopy by analyzing the effects of three major cytokines, IL-4, IL-12 and IFN-gamma on in vitro IgE synthesis of human peripheral blood mononuclear cell (PBMC) from normal individuals and atopic patients.

METHODS

We investigated 5 normal individuals and 22 atopic patients including 12 allergic asthma, 8 allergic rhinitis and 2 atopic dermatitis. Human PBMCs were separated and incubated in 96-wells culture plates with different cytokines. Cultured for 7 days, the supernatant was collected and the contents of IgE synthesized in vitro were detected.

RESULTS

There was no IgE synthesis in vitro of PBMC from all the normal individuals and 7 patients, however, other 15 patients' PBMC could produce IgE in vitro. We found that rhIL-4 could induce in vitro IgE synthesis of PBMC from all the normal individuals and 22 patients. rhIL-12 could inhibit IgE synthesis induced by rhIL-4. Further investigation of cytokine effects on IgE synthesis was conducted in 15 patients whose PBMCs did produce IgE in vitro (average level was 714 +/- 1105 ng/L). The following effects were observed: (1) 10 micrograms/L rhIL-4 could augment in vitro IgE synthesis from 714 +/- 1105 ng/L to higher level of 1483 +/- 1396 ng/L; (2) 20 micrograms/L rhIL-12 could inhibit in vitro IgE synthesis from 714 +/- 1105 ng/L to lower level of 452 +/- 969 ng/L; (3) rhIL-12 could block IgE synthesis induced by rhIL-4 to the level of 583 +/- 1084 ng/L; (4) 50 micrograms/L IFN-gamma could inhibit in vitro IgE synthesis from 714 +/- 1105 ng/L to the level of 461 +/- 1063 ng/L.

CONCLUSIONS

rhIL-4 could induce in vitro IgE synthesis, rhIFN-gamma could inhibit the in vitro IgE synthesis and rhIL-12 could antagonize rhIL-4 effect on in vitro IgE synthesis of PBMC from atopic patients.

[Changes in rat erythrocyte hemorheology caused by morphine dependence]

This study was aimed at the effect of morphine on the biomechanics properties of rat erythrocyte membrane in vivo and in vitro. The shear elastic modulus (E) and the surface viscotsity viscosity (micron) of rat erythrocyte membrane was measured by using the method of the new ektacytometry. The changes in hemorheology caused by morphine dependence were investigated and the mechanisms of the changes are suggested.

[The effect of thrombin on tissue factor activity in cultured bovine aortic endothelial cells and its correlation with PKC pathway]

OBJECTIVE

To study the stimulating effect of thrombin on the expression of tissue factor (TF) activity in cultured bovine aortic endothelial cells (BAEC) and to elucidate if it is associated with the PKC system.

METHODS

The BAECs were cultured after the Schwartz's method and one stage clotting time assay was used to measure TF activity in BAEC lysates. The TF activity was identified by EDGR-VIIa and a monoclonal antibody against TF.

RESULTS

Thrombin enhanced the expression of TF activity in cultured BAEC and the effect was dose- (r = 0.78, P < 0.05, n = 8) and time-dependent (r = 0.88, P < 0.05, n = 8). PMA, a PKC activator, also induced the expression of TF activity in BAEC. H7, a protein kinase C inhibitor, inhibited the inductive effects of PMA and thrombin on TF in BAEC.

CONCLUSION

Thrombin can induce the expression of TF activity in cultured BAEC and the effect depends on PKC pathway.