Spiers Memorial Lecture. Breeding and building molecular spies

To circumvent the limited spatial resolution of fluorescent protein imaging, we are developing genetically encoded tags for electron microscopy (EM).

Inflammatory pseudotumoural endotracheal mucormycosis with cartilage damage

Mucormycosis is a rare opportunistic infection usually associated with immunosuppression, diabetes mellitus or haematological malignancy. Herein, we report an unusual case of mucormycosis in a 46-yr-old male patient with diabetes presenting with an endotracheal mass obstructing the trachea and cartilage damage. Histological examination of the bronchoscopy biopsy specimens revealed invasive mucormycosis. The patient was treated with intravenous amphotericin B followed by removal of the lesion via bronchoscopy.

Cancer risk among patients hospitalized for Type 1 diabetes mellitus: a population-based cohort study in Sweden

AIMS

Type 1 diabetes mellitus (T1DM) is an autoimmune disease with potential mechanistic links to immune-related cancers. We aimed at examining the overall and specific cancer risks among hospitalized T1DM patients from the national registers in Sweden.

METHODS

A T1DM research cohort was created by identifying T1DM patients from the Hospital Discharge Register and linking them with the Cancer Registry. Standardized incidence ratios (SIRs) for subsequent cancers were calculated among patients with T1DM compared with those without T1DM.

RESULTS

Two hundred and fifty-eight cases were ascertained with subsequent cancers during the follow-up duration from 1964 to 2006, with an increased overall SIR of 1.17 (95% CI 1.04-1.33) among 24 052 T1DM patients identified at baseline. Significant excess was noted for gastric and skin (squamous cell carcinoma) cancers and for leukaemia. Increased risk of acute lymphatic leukaemia accounted for most of the variation of leukaemia risk (SIR = 5.31, 95% CI 3.32-8.05). Cancer risk varied with sex, age at first hospitalization and numbers of hospitalizations. The risk was higher in women compared with men and in those hospitalized for T1DM at age over 10 years compared with the younger patients. Higher risks were also found among those with more hospital visits.

CONCLUSION

By quantifying the variations of overall and site-specific cancer risks after T1DM, the current study provides novel associations between T1DM and subsequent cancers, the mechanisms of which remain to be established.

Cancer risk in hospitalised asthma patients

Asthma is an increasingly common disorder, affecting 5–10% of the population. It involves a dysregulated immune function, which may predispose to subsequent cancer. We examined cancer risk among Swedish subjects who had hospital admission once or multiple times for asthma. An asthma research database was created by identifying asthma patients from the Swedish Hospital Discharge Register and by linking them with the Cancer Registry. A total of 140 425 patients were hospitalised for asthma during 1965–2004, of whom 7421 patients developed cancer, giving an overall standardised incidence ratio (SIR) of 1.36. A significant increase was noted for most sites, with the exception of breast and ovarian cancers and non-Hodgkin's lymphoma and myeloma. Patients with multiple hospital admissions showed a high risk, particularly for stomach (SIR 1.70) and colon (SIR 1.99) cancers. A significant decrease was noted for endometrial cancer and skin melanoma. Oesophageal and lung cancers showed high risks throughout the study period, whereas stomach cancer increased towards the end of the period. The relatively stable temporal trends suggest that the asthmatic condition rather than its medication is responsible for the observed associations.

Effect of Helicobacter pylori eradication on oncogenes and cell proliferation

BACKGROUND

Helicobacter pylori , the main cause of chronic gastritis, is a class 1 gastric carcinogen. However, it remains unclear whether H. pylori affects molecular alterations in chronic gastritis. Thus, this study was designed to investigate the effect of H. pylori eradication on the expression of human telomerase RNA (hTR), human telomerase reverse transcriptase (hTERT), c-myc and proliferation nuclear cell antigen (PCNA) in H. pylori associated chronic gastritis.

MATERIALS AND METHODS

hTR was determined by in situ hybridization, hTERT, c-myc and PCNA were detected by immunohistochemistry using stomach tissues obtained from 39 H. pylori-infected and 21 H. pylori-negative patients with chronic gastritis before and after H. pylori eradication therapy or treatment for symptom relief only.

RESULTS

Levels of hTR, hTERT, c-myc and PCNA were significantly higher in H. pylori-infected mucosa (51.3%, 53.8%, 53.8% and 16.8 +/- 5.8, respectively) when compared to H. pylori-negative mucosa before therapy (19.0%, 23.8%, 28.6%, 8.8 +/- 3.4, respectively; P < 0.05 in all cases). In patients with successful eradication of H. pylori the levels of hTR, hTERT, c-myc and PCNA (55.5%, 59.3%, 59.3%, 16.8 +/- 5.8, respectively) were significantly reduced after the therapy (22.2%, 22.2%, 14.8%, 7.0 +/- 5.0, respectively; P < 0.05 in all cases). In the H. pylori failed eradication and H. pylori-negative groups, there was no statistical difference in all four measurements.

CONCLUSIONS

H. pylori infection may induce the overexpression of hTR, hTERT, c-myc and stimulate cell proliferation. Eradication of H. pylori may reverse the aberrant expression of these oncoproteins and thus correct the abnormal cell proliferation.

Influence of UGT1A9 intronic I399C>T polymorphism on SN-38 glucuronidation in Asian cancer patients

Genetic polymorphisms in hepatically expressed UGT1A1 and UGT1A9 contribute to the interindividual variability i-n irinotecan disposition and toxicity. We screened UGT1A1 (UGT1A1*60, g.-3140G>A, UGT1A1*28 and UGT1A1*6) and UGT1A9 (g.-118(T)(9>10) and I399C>T) genes for polymorphic variants in the promoter and coding regions, and the genotypic effect of UGT1A9 I399C>T polymorphism on irinotecan disposition in Asian cancer patients was investigated. Blood samples were collected from 45 patients after administration of irinotecan as a 90 min intravenous infusion of 375 mg/m(2) once in every 3 weeks. Genotypic-phenotypic correlates showed that cancer patients heterozygous or homozygous for the I399C>T allele had approximately 2-fold lower systemic exposure to SN-38 (P<0.05) and a trend towards a higher relative extent of glucuronidation (REG) of SN-38 (P>0.05). UGT1A1-1A9 diplotype analysis showed that patients harbouring the H1/H2 (TG6GT(10)T/GG6GT(9)C) diplotype had 2.4-fold lower systemic exposure to SN-38 glucuronide (SN-38G) compared with patients harbouring the H1/H5 (TG6GT(10)T/GG6GT(10)C) diplotype (P=0.025). In conclusion, this in vivo study supports the in vitro findings of Girard et al. and suggests that the UGT1A9 I399C>T variant may be an important glucuronidating allele affecting the pharmacokinetics of SN-38 and SN-38G in Asian cancer patients receiving irinotecan chemotherapy.

Hepatic expression of UGT enzymes and implications in pharmacokinetic variations in Asians during chemotherapy

14089

Background: The objective of this study was to screen the promoter and relevant coding regions in the UGT1A1 and UGT1A9 genes and genotypically quantitate expression of these genes in hepatic tissues obtained from Asian cancer patients undergoing hepatectomy. Methods: Non-cancerous Asian hepatic tissues (Chinese: N=36; Malay: N=1; Indian: N=3) were obtained from the institution’s central tissue repository bank. Messenger RNA was isolated from each tissue sample and reverse transcribed to cDNA followed by real time PCR experiments. Results from these gene expression experiments were normalized against GAPDH transcripts. DNA was also extracted from the hepatocytes, screened for variations in the promoter regions (UGT1A1*60, g.3140G>A and UGT1A1*28) and exon 1 (UGT1A1*6) of the UGT1A1 and UGT1A9 (UGT1A9*22, I399C>T) genes. Results: Large interindividual variations were observed in the hepatic expression pattern of UGT1A1 and UGT1A9 mRNA with respect to the different polymorphic variants. There was no significant association between hepatic expression of UGT1A1 mRNA and UGT1A1*60, g-3140G>A and *6 genotypes (P>0.05 in each case). The median expression level of UGT1A1 mRNA was approximately 2-fold higher in liver tissues harboring UGT1A1 6/6 (reference) genotype (N=27, median = 0.478; range: 0.065 to 3.125) compared to the heterozygous 6/7 genotype (N=9, median = 0.254; range: 0.042 to 1.894; P=0.77). The median expression levels of UGT1A9 mRNA were approximately 3-fold higher in liver tissues harboring I399CC genotype (N=3, median = 2.735; range: 0.702 to 3.375) when compared with the homozygous variant TT genotype (N=8, median = 0.973; range: 0.652 to 4.155; P=0.88). Conclusions: The results showed that polymorphisms in the UGT1A genes may influence the expression pattern of the respective proteins and could contribute to the high degree of interpatient variability in the glucuronidation dependent metabolism and elimination of chemotherapeutic agents in Asian cancer patients.

No significant financial relationships to disclose.

All-optical demultiplexing of 640 to 40 Gbits/s using filtered chirp of a semiconductor optical amplifier

We present a high-capacity ultrafast all-optical time demultiplexer that can be employed to retrieve 40 gigabits/second (Gb/s) base-rate channels from a 640 Gb/s single-polarized signal. The demultiplexer utilizes ultrafast effects of filtered chirp of a semiconductor optical amplifier. Excellent demultiplexing performance is shown at very low switching powers: +8 dBm (640 Gb/s data) and -14 dBm (40 GHz clock). The demultiplexer has a simple structure and, in principle, allows monolithic integration.

[Effect of TCM syndrome-typing based therapy combined with cyclosporin in treating myelodysplastic syndrome]

OBJECTIVE

To observe the therapeutic effect of TCM syndrome-typing based therapy (TCM-STBT) combined with cyclosporin on myelodysplastic syndrome (MDS) and investigate the correlation of efficacy with TCM syndrome type and MDS type.

METHODS

Fifty-eight MDS patients were classified into refractory anemia (RA) and RA with excess blast (RAEB) by FAB standard and randomly divided into the cyclosporin group (the treated group) and the alltransretinoic acid group (the control group), and both were subjected to STBT additionally. The therapeutic effect and changes of peripheral hemogram were observed and compared.

RESULTS

The total effective rate and the total remission rate was 73% and 33% in the treated group, higher than that in the control group (39% and 0) respectively. Hemoglobin level, white blood cell and blood platelet count increased significantly in the treated group after treatment (P < 0.05), while only hemoglobin level rose obviously in the control group (P < 0.05). The total effective rate and markedly effective rate in patients with qi-blood deficiency syndrome type were higher than those with other syndrome types.

CONCLUSION

TCM-STBT combined with cyclosporin has good efficacy in treating MDS and there is well correlation between the therapeutic efficacy and type of TCM syndrome or of MDS, indicating the STBT is necessory for TCM therapy.

RPGR ORF15 isoform co-localizes with RPGRIP1 at centrioles and basal bodies and interacts with nucleophosmin

The ORF15 isoform of RPGR (RPGR(ORF15)) and RPGR interacting protein 1 (RPGRIP1) are mutated in a variety of retinal dystrophies but their functions are poorly understood. Here, we show that in cultured mammalian cells both RPGR(ORF15) and RPGRIP1 localize to centrioles. These localizations are resistant to the microtubule destabilizing drug nocodazole and persist throughout the cell cycle. RPGR and RPGRIP1 also co-localize at basal bodies in cells with primary cilia. The C-terminal (C2) domain of RPGR(ORF15) (ORF15(C2)) is highly conserved across 13 mammalian species, suggesting that it is a functionally important domain. Using matrix-assisted laser desorption ionization time-of-flight mass spectrometry, we show that this domain interacts with a 40 kDa shuttling protein nucleophosmin (NPM). The RPGR(ORF15)-NPM interaction was confirmed by (i) yeast two-hybrid analyses; (ii) binding of both recombinant and native HeLa cell NPM to RPGR(ORF15) fusion proteins in vitro; (iii) co-immunoprecipitation of native NPM, RPGR(ORF15) and RPGRIP1 from bovine retinal extracts and of native HeLa cell NPM and transfected RPGR(ORF15) from cultured cells and (iv) co-localization of NPM and RPGR(ORF15) at metaphase centrosomes in cultured cells. NPM is a multifunctional protein chaperone that shuttles between the nucleoli and the cytoplasm and has been associated with licensing of centrosomal division. RPGR and RPGRIP1 join a growing number of centrosomal proteins involved in human disease.

Fine-tuning the degree of organic functionalization of mesoporous silica nanosphere materials via an interfacially designed co-condensation method

A synthetic method that can fine tune the amount of chemically accessible organic functional groups on the pore surface of MCM-41 type mesoporous silica nanosphere (MSN) materials has been developed by electrostatically matching various anionic organoalkoxysilanes with the cationic cetyltrimethylammonium bromide micelles in a base-catalyzed condensation reaction of tetraethoxysilane.

[Evaluation of therapeutic efficacy by detection of specific IgG and IgG4 against KLH in schistosomiasis japonica]

The specific IgG and IgG4 antibodies in the sera of patients with Schistosoma japonicum were determined by KLH-ELISA and SEA-ELISA. The results showed that KLH-ELISA was as sensitive and specific as SEA-ELISA. The negative conversion rates of IgG and IgG4 12 months after treatment detected by KLH-ELISA were significantly higher than those by SEA-ELISA. The negative conversion rate of IgG was 92.9%, and that of IgG4 was 97.6% 24 months after treatment. Therefore, it is regarded that detecting specific IgG and IgG4 by KLH has high value in both diagnosing schistosomiasis japonica and assessing its therapeutic efficacy. Particularly the specific IgG4 may be a short-duration antibody which can indicate successful chemotherapy of patients with chronic Schistosoma japonicum infection.

[Schistosoma japonicum: protective immunity induced in mice immunized with SjGST-Sj32]

Schistosoma japonicum glutathione-s-transferase (SjGST), Schistosoma japonicum 32,000 protein (Sj32) and SjGST - Sj32 were expressed and purified to study on protective immunity against Schistosoma japonicum. The result showed that compared with the adjuvant control group, the worm burden was decreased significantly in mice immunized with recombinant SjGST - Sj32, Sj32 and Sj32 + SjGST (P < 0.05). At the same time, the liver egg per gram(EPG) was decreased in mice immunized with SjGST - Sj32, Sj32, Sj32 + SjGST and SjGST. It is concluded that Sj32 significantly induces both protective immunity and anti-fecundity immunity, but SjGST only has an anti-fecundity effect.

Acute sensitization by NGF of the response of small-diameter sensory neurons to capsaicin

We investigated acute sensitization by nerve growth factor (NGF) of the response of small-diameter (<30 microm) dissociated dorsal root ganglion (DRG) cells to brief repeated puffs of capsaicin as a model for thermal hyperalgesia induced by NGF. We have previously shown that placing NGF in the bath after an initial puff of capsaicin can completely overcome the tachyphylaxis normally observed in response to a second puff 10 min later, and this response is often substantially larger than the first. If tachyphylaxis is abolished by carrying out the experiment in Ca2+-free solution, NGF still elicits potentiation of the second puff. However, the amount of potentiation is considerably less than that observed when tachyphylaxis also takes place. Thus it is concluded that NGF has two effects: overcoming tachyphylaxis and potentiation. With three puffs of capsaicin separated by 10 min, we have found that the potentiation established after 10 min exposure to NGF is no longer evident 10 min after removal of NGF. In Ca2+-free solution the potentiation can last up to 1 h after removal of NGF. These results suggest that the initial behavioral sensitization elicited by NGF could result from a direct effect on the sensory neuron but that its later components most likely involve other mechanisms. We have also investigated the contribution of various second-messenger pathways in these actions of NGF by treating the cells with blockers of MAP kinase (PD98059), protein kinase A (PKA; PKAI14-22, H89), and PKC (Bisindolylmaleimide I). Surprisingly, PD98059, which previously has been shown to diminish the enhancement of capsaicin responses of dissociated neurons when exposed to NGF for several days, had no effect on the acute response to NGF; nor did the PKC inhibitor. However, PKA inhibitors reduced the capsaicin response of the cells to NGF (as determined from the NGF effect on tachyphylaxis). Consistent with these findings we confirmed that forskolin, a PKA activator, enhances the effect of NGF on the capsaicin response. The percentage of small cells sensitized by NGF under these conditions, as determined by its ability to reduce tachyphylaxis, was 64%. This suggests that about two-thirds of DRG cells <30 microm and sensitive to capsaicin express a functional trkA receptor.

[Pathological changes between HBeAg and anti-HBe in patients with chronic hepatitis B]

OBJECTIVE

To observe the differences of pathological changes between HBeAg and anti-HBe in chronic hepatitis B.

METHODS

Liver biopsy was performed in patients with chronic hepatitis B. The histopathological grading and staging were carried out. Serum markers of viral hepatitis were tested.

RESULTS

(1) The histopathological grading and staging were closely correlated with the appearance of serum HBeAg and anti-HBe. The number of G(3-4) and S(3-4) in anti-HBe cases was significantly higher than that of G(1-2) and S(1-2), respectively. The number of G(1-2) and S(1-2) in HBeAg cases was significantly higher than that of G(3-4) and S(3-4), respectively. Significant differences were found between the group of anti-HBe cases and the group of HBeAg cases (P<0.005). (2) HBV DNA was detected in 126 of 151 HBeAg positive patients (83.4%), and the positive rate of HBV DNA in anti-HBe positive patient was 29% only.

CONCLUSIONS

(1) Severe inflammatory, necrosis and fibrosis of hepatic tissue are observed in patients with anti-HBe positive chronic hepatitis B. (2) Although HBV DNA is positively correlated to HBeAg, HBV-DNA can be detected in part of anti-HBe positive patients.

Sensitivity characteristics near the dispersion turning points of long-period fiber gratings in B/Ge codoped fiber

We report a theoretical and experimental investigation of the dispersion property of long-period fiber gratings in B/Ge codoped fiber. A novel concept of a mode ultrasensitive zone defined by a region in which the phase-matching conditions are close to the dispersion turning points is proposed. The transition from a dual-resonance state to a dispersion turning point is revealed for a set of ultrasensitive-zone gratings during the UV-writing process. We explore the sensitivity characteristics near the dispersion turning points, with the aim of implementing two types of temperature sensor with sensitivity 2 orders of magnitude higher than that of the conventional long-period gratings.

Sampled fiber Bragg grating for simultaneous refractive-index and temperature measurement

We present a novel scheme for simultaneous measurement of temperature and refractive index by use of a single sampled fiber Bragg grating (SFBG). The intrinsic nature of a SFBG that possesses both fiber Bragg grating and long-period grating spectral responses permits the temperature effect to the measured solely from the former, whereas the refractive-index information is extracted from the latter. Using such a dual-parameter sensor, we successfully demonstrated measurement of the dependence on temperature of the refractive index of an aqueous solution of sucrose.

[Schistosoma japonicum: purification and diagnostic application of recombinant 32 kD antigen]

Separation and purification of rSj32 were carried out with SDS-PAGE and electroelution technique. The purified rSj32, AWA and SEA were used to examine sera of patients with schistosomiasis, healthy individuals and patients with other parasitic diseases by ELISA. The results showed that the molecule weight of rSj32 was 37 kD. The sensitivity and specificity of rSj32 as a coating antigen in ELISA were as good as those of AWA and SEA. It is suggested that rSj32 antigen is a potential antigen for immunodiagnosis of schistosomiasis japonica.

[Characterization of cefoperazone resistance gene on plasmid pFC in E. coli HX88108]

OBJECTIVE

To investigate the characterization of cefoperazone resistance gene (CPZr) on plasmid pFC in E. coli HX88108 and inquire into the mechanism of resistance to CPZ at the molecular level.

METHODS

E. coli HX88108 strain which demonstrated high-level resistance to cefoperazone (MIC, > 512 micrograms/ml) was isolated from a severely infected patient in 1988. Five plasmids coexisting in the strain were designated pFC, pFT1; pFT2, pFT3 and pFX, respectively. Four plasmids except pFX conferred CPZ resistance. Cefoperazone resistance gene (CPZr) has been cloned from plasmid pFC. beta-lactamase assays with Nitrocefin were performed.

RESULTS

The expression product of CPZr was beta-lactamase. The high level beta-lactamase enzymatic activities against cephaloridine of CPZr transformants which were detected spectrophotometrically at 260 nm wave length demonstrated high level similarities to that of pFC. MICs of 18 antibiotics were determined according to a guideline of NCCLS by broth dilution method. CPZr transformants showed moderate level resistance to ampicillin, cefazolin, cefazolin, cefamandole and CPZ (MIC, 64 micrograms/ml). Meanwhile, susceptibility testing results demonstrated that the level of resistance to CPZ of pFC transformant in this study (MIC, 64 micrograms/ml) was much lower than that in 1988 (MIC, > 512 micrograms/ml) and resistance to nofloxacin and aminoglycosides was not observed. Induction experiment and temperature-sensitive mutation of CPZ resistance were performed. CPZr colonal strains revealed the higher-level of resistance to CPZ (MIC, 512 micrograms/ml) due to antibiotic CPZ induction rather than temperature sensitive mutation.

CONCLUSION

This observation suggests that resistance to antibiotics encoded by plasmid might have been lower or lost under no antibiotic stress in a certain period, but higher under heavy stress.

Control of intramolecular interactions between the pleckstrin homology and Dbl homology domains of Vav and Sos1 regulates Rac binding

Vav and Sos1 are Dbl family guanine nucleotide exchange factors, which activate Rho family GTPases in response to phosphatidylinositol 3-kinase products. A pleckstrin homology domain adjacent to the catalytic Dbl homology domain via an unknown mechanism mediates the effects of phosphoinositides on guanine nucleotide exchange activity. Here we tested the possibility that phosphatidylinositol 3-kinase substrates and products control an interaction between the pleckstrin homology domain and the Dbl homology domain, thereby explaining the inhibitory effects of phosphatidylinositol 3-kinase substrates and stimulatory effects of the products. Binding studies using isolated fragments of Vav and Sos indicate phosphatidylinositol 3-kinase substrate promotes the binding of the pleckstrin homology domain to the Dbl homology domain and blocks Rac binding to the DH domain, whereas phosphatidylinositol 3-kinase products disrupt the Dbl homology/pleckstrin homology interactions and permit Rac binding. Additionally, Lck phosphorylation of Vav, a known activating event, reduces the affinities between the Vav Dbl homology and pleckstrin homology domains and permits Rac binding. We also show Vav activation in cells, as monitored by phosphorylation of Vav, Vav association with phosphatidylinositol 3,4,5-trisphosphate, and Vav guanine nucleotide exchange activity, is blocked by the phosphatidylinositol 3-kinase inhibitor wortmannin. These results suggest the molecular mechanisms for activation of Vav and Sos1 require disruption of inhibitory intramolecular interactions involving the pleckstrin homology and Dbl homology domains.

[Stress-corrosion test of laser welded ceramic alloys]

OBJECTIVE

The corrosion properties of dental material are very critical. This study is to investigate the corrosion properties of laser welded basemetalalloys.

METHODS

The precise stainless rod molds had been made in size of phi 3 mm x 4 mm, with which 20 wax patterns were made. They were invested with inner investment (Bellavest) and outer investment (phosphate and gypsum). Then they were casted with CW-PA (Ni-Cr-Nb) alloys. All casted alloy rods were ultra-sonic washed in distilled water. Every two rods were contacted longitudinally by a special welding jig. Laser welding machine (DL-2002) was used to weld them at 305 V, 20 ms. The specimens were divided into 2 groups as following: 1. The group of stress-corrosion: 5 laser welded samples were subjected to the stress-corrosion test under 261.44 MPa in the 37 degrees C artificial saliva for 3 months in a special stress-corrosion test jig. After that, the ultimate tensile strength (UTS) was tested, the surface microcrack at the fusion zone (FZ), the heat affecting zone (HAZ) and the interface zone was observed with SEM (ARMY-1845, USA), the elements were also analyzed with EPMA (ARMY-1845, USA) at the fusion zone (FZ), the parent metal zone and the interface zone. 2. The other 5 laser welded samples were made as the controlled group. No special treatment were done to them, and the UTS was also tested, the surface of the micro crack and the elements at the FZ, the HAZ, parent metal zone and the interface zone were observed and analyzed with SEM, EPMA as well.

RESULTS

The study showed us that the UTS of the stress-corrosion group was 502.48 +/- 12.49 MPa, while that of the controlled group was 446.05 +/- 82.50 MPa, there was no significant difference (P > 0.05). There was no microcrack on any sample's surface at the FZ, the HAZ and the interface zone. The main elements of the FZ were Ni(56.63%), Cr(19.36%), Nb (6.57%), Si(6.01%), Al(0.32%) and Mo(11.11%), while the elements of the parent metal zone were Ni(60.77%), Cr (20.59%), Nb(5.03%), Si(3.95%), Al(0.37%) and Mo(9.29%) respectively.

CONCLUSION

The results suggest that the corrosion properties of laser welded alloys are excellent.

[Schistosoma japonicum ferritin: cloning, nucleotide sequencing, expression, and purification]

Our previous work showed that immunization of mice with Schistosoma japonicum (Sj) immature eggs induced significant immunity against fecundity and embryonation of the parasite. The Sj adult cDNA library was screened by sera from rabbits against Sj immature egg antigen (RASjIEA). The genes encoding molecules which may induce immunity against fecundity/embryonation were chosen for further cloning and expression. First of all, RASjIEA was absorbed with E. coli lysate to remove cross reactive antibodies. The cDNA library was then immunoscreened using the routine method. The resulted positive plaques were rescreened till individual clones were confirmed. Phagemids were obtained using in vivo excision. The positive clones were amplified using PCR. The sizes of the genes were determined by agarose gel electrophoresis. After DNA sequencing of the genes cloned, Gene bank was searched and six different genes were identified from a total of 102 positive clones. One of six identified genes, Sj ferritin (SjFer) was chosen to subclone into pGMC vector. According to DNA sequences of Sj Fer and MCS (multiple cloning site) of the vector, forward primer (Fer/GMC1) and reverse primer (Fer/GMC2) were designed and used to amplify Sj Fer by PCR. The Sj Fer cDNA and expression vector pGMC were digested with BamHI and XhoI. The digested cDNA and pGMC were ligased by T4 DNA ligase to construct a recombinant which was then used to transform E. coli strain ER2566. The fusion protein GMCSF-Sj Ferritin was expressed in insoluble form, the inclusion body. Pellets were harvested and resolved in Tris-HCl buffer containing 8M urea. GMCSF-Sj Ferritin was purified by affinity chromatography using Ni-NTA resin. The molecular weight was determined by SDS-PAGE. This study first reports the gene encoding S. japonicum ferritin as a new candidate for schistosome vaccine.

Nerve growth factor acutely sensitizes the response of adult rat sensory neurons to capsaicin

Perforated patch clamp recordings were made from 118 voltage clamped (-60 mV), capsaicin-responsive dorsal root ganglion (DRG) cells (<30 microns) maintained in dissociated cell culture (6-24 h). A second puff of capsaicin 10 min later always evoked a substantially smaller inward current than the initial puff (tachyphylaxis). Bath-application of NGF (2, 10 or 100 ng/ml) during the 10-min interval resulted in facilitation of the second response in a dose dependent manner in 67% of cells studied. NT-4/5 exerted similar effects but NT-3 did not. Ten minute pretreatment with NGF increased the initial response to capsaicin. We conclude that NGF acutely conditions the response to capsaicin via direct action on DRG cells. Since the capsaicin receptor (VR1) mediates noxious heat sensitivity of polymodal nociceptors, acute sensitization of the noxious heat response by NGF and NT-4/5 may involve a direct action on VR1.