Visual function at baseline and 1 month in acute optic neuritis: predictors of visual outcome

OBJECTIVE

To identify cutpoints for visual measures at baseline and 1 month predictive of abnormal 6-month vision that could be used as eligibility criteria in a clinical trial to test potential neuroprotection or myelin repair agents in patients with optic neuritis. To determine whether moderate-to-severe dysfunction in one or more visual measures at baseline or 1 month correlates with having major vision loss at 6 months.

METHODS

We used the Optic Neuritis Treatment Trial database to evaluate various cutpoints for baseline and 1-month vision levels that predicted abnormal 6-month vision. For selected cutpoints, we computed a 95% CI for positive predictive value and the required sample size if the cutpoint was to be used for clinical trial eligibility. We evaluated whether the degree of visual loss at baseline, 1 month, or change in visual function from baseline to 1 month correlated with 6-month visual acuity, contrast sensitivity, or threshold visual field.

RESULTS

The best cutpoints for baseline and 1 month were visual acuity <or= 20/50, contrast sensitivity < 1.0 log units, and visual field mean deviation <or= -15 dB. The same levels of visual dysfunction at 1 month, but not at baseline, correlated with having 6-month moderate-to-severe loss for each of these measures (p = 0.01). A trial could require as few as 100 subjects for an outcome variable of one or more abnormal measures. Cutpoints at 1 month were highly predictive of abnormal 6-month vision, but the proportion of patients who would be eligible for a trial would be small.

CONCLUSION

Provided data can be used either for the clinician to counsel patients on expected visual outcome or for designing studies to test therapies that might reduce the amount of permanent optic nerve damage due to optic neuritis in high-risk patients.

Ex vivo expanded umbilical cord blood T cells maintain naive phenotype and TCR diversity

BACKGROUND

Umbilical cord blood (CB) is a promising source of hematopoietic stem cells for allogeneic transplantation. However, delayed engraftment and impaired immune reconstitution remain major limitations. Enrichment of donor grafts with CB T cells expanded ex vivo might facilitate improved T-cell immune reconstitution post-transplant. We hypothesized that CB T cells could be expanded using paramagnetic microbeads covalently linked to anti-CD3 and anti-CD28 Ab.

METHODS

CB units were divided into three fractions: (1) cells cultured without beads, (2) cells cultured with beads and (3) cells cultured with beads following CD3+ magnetic enrichment. All fractions were cultured for 14 days in the presence of IL-2 (200 IU/mL).

RESULTS

A mean 100-fold expansion (range 49-154) of total nucleated cells was observed in the CD3+ magnetically enriched fraction. Following expansion, CB T cells retained a naive and/or central memory phenotype and contained a polyclonal TCR diversity demonstrated by spectratyping.

DISCUSSION

Our data provide evidence that naive and diverse CB T cells may be expanded ex vivo and warrant additional studies in the setting of human CB transplantation.

Superior ex vivo cord blood expansion following co-culture with bone marrow-derived mesenchymal stem cells

One factor limiting the therapeutic efficacy of cord blood (CB) hematopoietic progenitor cell (HPC) transplantation is the low cell dose of the graft. This is associated with an increased incidence of delayed or failed engraftment. Cell dose can be increased and the efficacy of CB transplantation potentially improved, by ex vivo CB expansion before transplantation. Two ex vivo CB expansion techniques were compared: (1) CD133+ selection followed by ex vivo liquid culture and (2) co-culture of unmanipulated CB with bone-marrow-derived mesenchymal stem cells (MSCs). Ex vivo culture was performed in medium supplemented with granulocyte colony-stimulating factor, stem cell factor and either thrombopoietin or megakaryocyte growth and differentiation factor. Expansion was followed by measuring total nucleated cell (TNC), CD133+ and CD34+ cell, colony-forming unit and cobblestone area-forming cell output. When compared to liquid culture, CB-MSC co-culture (i) required less cell manipulation resulting in less initial HPC loss and (ii) markedly improved TNC and HPC output. CB-MSC co-culture therefore holds promise for improving engraftment kinetics in CB transplant recipients.

A novel triple purge strategy for eliminating chronic myelogenous leukemia (CML) cells from autografts

Imatinib-refractory chronic myelogenous leukemia (CML) patients can experience long-term disease-free survival with myeloablative therapy and allogeneic hematopoietic cell transplantation; however, associated complications carry a significant risk of mortality. Transplantation of autologous hematopoietic cells has a reduced risk of complications, but residual tumor cells in the autograft may contribute to relapse. Development of methods for purging tumor cells that do not compromise the engraftment potential of the normal hematopoietic cells in the autograft has been a long-standing goal. Since primitive CML cells differentiate more rapidly in vitro than their normal counterparts and are also preferentially killed by mafosfamide and imatinib, we examined the purging effectiveness on CD34(+) CML cells using a strategy that combines a brief exposure to imatinib (0.5-1.0 microM for 72 h) and then mafosfamide (30-90 microg/ml for 30 min) followed by 2 weeks in culture with cytokines (100 ng/ml each of stem cell factor, granulocyte colony-stimulating factor and thrombopoietin). Treatment with 1.0 microM imatinib, 60 microg/ml mafosfamide and 14 days of culture with cytokines eliminated BCR-ABL(+) cells from chronic phase CML patient aphereses, while preserving normal progenitors. This novel purging strategy may offer a new approach to improving the effectiveness of autologous transplantation in imatinib-refractory CML patients.

AML-loaded DC generate Th1-type cellular immune responses in vitro

BACKGROUND

The generation of AML-specific T-lymphocyte responses by leukemia-derived DC has been documented by multiple investigators and is being pursued clinically. An obstacle to widespread use of this strategy is that it has not been possible to generate leukemic DC from all patients, and an alternative approach is needed if the majority of leukemia patients are to receive therapeutic vaccination in conjunction with other treatment protocols.

METHODS

In the present study, we generated DC from CD14-selected monocytes isolated from healthy donor PBPC and loaded them with a total cell lysate from AML patient blasts.

RESULTS

Immature in vitro-derived DC exhibited robust phagocytic activity, and mature DC demonstrated high expression of CD80, CD83, CD86 and the chemokine receptor CCR7, important for DC migration to local lymph nodes. Mature, Ag-loaded DC were used as APC for leukemia-specific cytotoxic T-lymphocyte (CTL) induction and demonstrated cytotoxic activity against leukemic targets. CTL lysis was Ag-specific, with killing of both allogeneic leukemic blasts and autologous DC loaded with allogeneic AML lysate. HLA-matched controls were not lysed in our system.

DISCUSSION

These data support further research into the use of this strategy as an alternative approach to leukemia-derived DC vaccination.

Treatment of mice with IL-12 DNA constructs leads to augmented NK activity in lungs but low IFN-gamma release -- implications for Bordetella pertussis infections following aerosol challenge

Interleukin-12 protein has been widely used experimentally in therapeutic and adjuvant settings in the treatment of different diseases including intra-cellular bacterial infections. The in vivo clearance of Bordetella pertussis infections in naive mice and in animals vaccinated with whole cell vaccine is considered to be a Th-1 dependent mechanism. Furthermore, the addition of IL-12 protein to an acellular pertussis vaccine increases the efficacy of this vaccine. Whilst the use of IL-12 protein is often beneficial, a number of problems there are associated with this cytokine including toxicities and down regulation of normal immune functions. The use of DNA constructs encoding this cytokine may be a way of achieving maximum therapeutic benefit with minimum toxicity. The aims of this study were to optimise the effects of two IL-12 DNA constructs, especially with respect to augmenting pulmonary immune responsiveness and to compare the effect of IL-12 DNA and IL-12 protein on bacterial colonisation of lungs following aerosol challenge with B. pertussis. We found that IL-12 DNA constructs augmented the activity of pulmonary NK cells but had little effect on the course of B. pertussis infections in mice. In contrast to IL-12 protein, the DNA constructs had no immunosuppressive effects on splenic lymphocyte mitogen responses.

High dose interleukin-12 exacerbates Bordetella pertussis infection and is associated with suppression of cell-mediated immunity in a murine aerosol challenge model

The in-vivo clearance of Bordetella pertussis infections in murine models in naive mice and animals vaccinated with whole-cell vaccine is considered to be via a Th-1-dependent mechanism in which interleukin-12 (IL)-12 may play a prominent role. It has also been demonstrated clearly that the treatment of animals with macrophage-derived IL-12 administered with an acellular vaccine can increase the efficacy of this vaccine preparation to levels seen with the whole-cell vaccine. However, the effects of exogenously added IL-12 on immune responses in non-vaccinated B. pertussis-challenged mice remain unclear, with two studies giving contradictory findings. In this study we have treated mice with escalating doses of mIL-12 (0.1-10 microg/mouse) prior to challenge with B. pertussis (using an aerosol challenge model of infection). The ability of mice to clear infection was assessed in IL-12 treated and in phosphate buffered saline (PBS) control animals at days 6 and 13 post-challenge. Lymphoid cells were isolated from spleen and cell-mediated immune responses assessed at days 1, 6 and 13 post-challenge. In addition, the direct effects of high-dose IL-12 on challenged mice was assessed by checking natural killer (NK) activity from isolated lung and spleen lymphoid cells as well as interferon-gamma (IFN-gamma) generation from isolated cells and serum at day 1 post-challenge. The results from this study show that bacterial colonization of the lungs is actually enhanced following treatment with high-dose IL-12. This is associated with impaired cellular immune responses. The mechanisms associated with the immunosuppressive effects of IL-12 are discussed.

Developments in reduction and replacement of in vivo toxicity and potency tests for pertussis vaccines

The regulatory control of pertussis vaccines, as for other biological products, requires that they conform to specified standards of safety and efficacy. The current potency test for whole cell vaccines, the intracerebral mouse protection test (AMPT) is still the only such assay that has shown a correlation with protection in children. An alternative in vivo assay based on non-lethal aerosol challenge of mice has been assessed as a replacement for the current AMPT. An in vitro assay based on determination of reactive nitrogen/oxygen intermediates produced as a result of macrophage activation has also been investigated as a potential replacement for the in vivo challenge test. On the other hand, for safety testing, an enzymatic-HPLC coupled assay using a fluorescein-labelled G alpha(i3)C20 peptide to measure the enzymatic ribosylation activity of active pertussis toxin was evaluated for its suitability as a replacement for the current histamine sensitisation test (HIST). An assay for adenylate cyclase toxin (ACT)-related toxicity, based on measuring the ACT-induced oxidative burst in macrophage-like cell cultures has also been investigated. Although some questions still need to be answered in relation to the development of suitable replacements for in vivo tests of pertussis vaccines, the prospects for further improvements are promising.

Comparison of the bioactivity of reference preparations for assaying Bordetella pertussis toxin activity in vaccines by the histamine sensitisation and Chinese hamster ovary-cell tests: assessment of validity of expression of activity in terms of protein concentration

Pertussis toxin (PT) in its detoxified form is an important antigenic component of both acellular and whole cell pertussis vaccines. Limits on the content of active PT in acellular vaccines are set in official monographs (EP, WHO, USP) and evidence of compliance is therefore, required by regulatory authorities. The two assay methods which are currently used by most manufacturers and official national control laboratories to monitor residual PT activity in acellular pertussis vaccines (and also in whole cell vaccines) are histamine sensitising (HIST) assays and Chinese hamster ovary (CHO) cell assays. Currently, different reference preparations of PT are used by individual laboratories for these tests. We therefore organised an international collaborative study to examine, by these two assay methods, two freeze-dried purified preparations of PT, one preparation in ampoules coded JNIH-5 and one preparation in ampoules coded 90/518, together with in-house reference (IHR) preparations in current use. Data from this study confirm that both JNIH-5 and 90/518 show biological activity both in HIST assays and in CHO-cell assays. Both HSD50 and ED50 values obtained in this study differ significantly between laboratories and thus show that biological activity is not determined by the nominal masses of preparations. Estimates of relative potency of 90/518 in terms of JNIH-5 per ampoule for the HIST assays do not differ significantly between laboratories. The overall mean estimates of relative potency of 90/518 in terms of JNIH-5 do not differ significantly between the two methods. Data from this study further indicate that the biological activity of different preparations was not directly related to their stated protein content. The use of protein content to indicate the level of PT activity in different preparations would give misleading results. Thus, use of a common standard is shown to greatly improve between laboratory agreement of estimates.

Investigation of role of nitric oxide in protection from Bordetella pertussis respiratory challenge

The mechanism whereby whole-cell pertussis vaccines (WCV) confer protection against Bordetella pertussis is still not fully understood. We have previously reported that macrophage activation produced by vaccination with WCV is associated with induction of NO synthesis by macrophages in response to in vitro stimulation with B. pertussis antigens. To determine whether NO production is an effector of protection or simply a marker of activation, the susceptibility of inducible nitric oxide synthase (type II, iNOS) knockout mice to infection with B. pertussis was examined. We showed that iNOS knockout mice were more susceptible to B. pertussis respiratory challenge than wild-type mice. iNOS-deficient mice also developed a less effective protective response than wild-type mice after the same immunization with WCV. This suggests that NO plays an important role in effecting protection against B. pertussis challenge.

Lymphoid apoptosis and myeloid hyperplasia in CCAAT displacement protein mutant mice

CCAAT displacement protein (cux/CDP) is an atypical homeodomain protein that represses expression of several developmentally regulated lymphoid and myeloid genes in vitro, including gp91-phox, immunoglobulin heavy chain, the T-cell receptor beta and gamma chains, and CD8. To determine how this activity affects cell development in vivo, a hypomorphic allele of cux/CDP was created by gene targeting. Homozygous mutant mice (cux/CDP(Delta HD/Delta HD)) demonstrated a partial neonatal lethality phenotype. Surviving animals suffered from a wasting disease, which usually resulted in death between 2 and 3 weeks of age. Analysis of T lymphopoiesis demonstrated that cux/CDP(Delta HD/Delta HD) mice had dramatically reduced thymic cellularity due to enhanced apoptosis, with a preferential loss of CD4(+)CD8(+) thymocytes. Ectopic CD25 expression was also observed in maturing thymocytes. B lymphopoiesis was also perturbed, with a 2- to 3-fold reduction in total bone marrow B-lineage cells and a preferential loss of cells in transition from pro-B/pre-BI to pre-BII stages due to enhanced apoptosis. These lymphoid abnormalities were independent of effects related to antigen receptor rearrangement. In contrast to the lymphoid demise, cux/CDP(Delta HD/Delta HD) mice demonstrated myeloid hyperplasia. Bone marrow reconstitution experiments identified that many of the hematopoietic defects were linked to microenvironmental effects, suggesting that underexpression of survival factors or overexpression of death-inducing factors accounted for the phenotypes observed. Tumor necrosis factor (TNF) levels were elevated in several tissues, especially thymus, suggesting that TNF may be a target gene for cux/CDP-mediated repression. These data suggest that cux/CDP regulates normal hematopoiesis, in part, by modulating the levels of survival and/or apoptosis factors expressed by the microenvironment.

Laboratory testing of whole cell pertussis vaccine: a WHO proficiency study using the Kendrick test

Whole cell pertussis vaccine (WCV), commonly in combination with vaccines for diphtheria and tetanus, has an important role in reducing morbidity and mortality among children in most parts of the world. Testing to assure the efficacy of such vaccines is essential. We have, therefore, carried out, under the Global Training Network (GTN) of the Department of Vaccines and Biologicals at the World Health Organization (WHO), a proficiency study involving 13 laboratories in 12 countries that routinely test WCV. Two vaccine samples were tested in this study and represented samples which were expected clearly either to pass (sample B, a full strength vaccine) or to fail (sample A, 1/8 strength of vaccine B). Data from this study showed good performance by the majority of participants. Most assays were statistically valid and were carried out to the level of precision achieved for these assays in previous studies. This study also indicated that, relative to the assay precision, the in-house reference (IHR) preparations are in general accurately calibrated. Statistically valid assays of the sub-potent vaccine, A, showed it to fail in all except one laboratory. Statistically valid assays of the potent vaccine, B, showed it to pass in all laboratories. Nevertheless, the between laboratory variability of estimates for vaccine B, and for comparisons of the two vaccine samples suggested that there are some differences in results in different laboratories. The introduction of a common working standard may assist in reducing inter-laboratory variation. This study has shown clearly satisfactory performance by most laboratories. However, a serious problem was detected in one laboratory where the sub-potent vaccine A could have been passed and was not distinguished from the eight-fold more potent vaccine B. There were also indications of possible problems in several other laboratories, where IHR preparation may not be accurately calibrated or where vaccine samples A and B may not be completely distinguished. Although this study provides reassurance that most laboratories perform well, it demonstrates the essential role of ongoing proficiency studies in high-lighting problems.

[Detection of malondialdehyde-DNA adduct level by 32P-postlabeling assay in normal human esophageal epithelium and esophageal squamous cell carcinoma]

OBJECTIVE

To study whether the main malondialdehyde-DNA adduct (M1-dG) produced by lipid peroxidation is involved in the carcinogenesis of esophagus.

METHODS

DNA samples were isolated from normal esophageal epithelium (n = 32) obtained by biopsy and esophageal squamous cell carcinoma specimens (n = 30) obtained by surgery. All tissue samples came from individuals living in Linxian, Henan, a high-risk area of esophageal cancer. Contents of M1-dG adducts were detected by 32P-postlabeling method.

RESULTS

M1-dG adducts were detectable both in the normal and cancerous tissue samples. However, normal esophageal epithelial tissues exhibited significantly lower levels of M1-dG adducts (median 3.4, range 1.7/10(8)-55.4/10(8) nucleotides) than those found in esophageal cancer tissues (median 14.1, range 1.4/10(8)-59.0/10(8) nucleotides, P < 0.0001). The adduct levels were neither associated with gender, age, tobacco smoking status or genetic polymorphism in the CYP2E1, an enzyme participating in the oxidation of ethanol to form reactive free radicals.

CONCLUSIONS

Our findings provide evidence that DNA damage, resulted from lipid peroxidation, can accumulate in the normal human esophageal tissue and reach relatively high level in cancer tissue which suggests that M1-dG adducts may be involved in the initiation and progression of cancer with its mutagenic and carcinogenic effects.

International collaborative study: evaluation of proposed International Reference Reagent of pertussis antiserum (mouse) 97/642

A freeze dried preparation of mouse serum in vials coded 97/642 containing antibodies to five pertussis antigens [pertussis toxin (PT), filamentous hemagglutinin (FHA), pertactin (PRN), fimbriae type 2 and 3 (Fim 2 and 3)] has been assessed for its suitability as an international reference reagent in an international collaborative study by thirteen laboratories in nine countries. This serum has been compared with U.S. Standard Pertussis Antiserum (mouse) Lot No. 1 (US Lot 1), which has been in use since 1995, for antibodies for each antigen. Calibration of the proposed International Reference Reagent of Pertussis Antiserum (pIRR) in terms of US Lot 1 gives results which are broadly consistent between laboratories for antibodies to each antigen, although the between-laboratory differences are larger than those seen for comparison of identical sera. Calibration of two positive control sera in terms of the pIRR gave similar between laboratory variability of estimates to that obtained when the same sera were calibrated in terms of US Lot 1. Overall continuity of estimates is maintained if units are assigned to the pIRR based on its calibration in terms of US Lot 1 in this study. Data presently available indicate that the pIRR is sufficiently stable to serve as a reference reagent. It was therefore recommended, with the agreement of all participants, that the preparation in vials coded 97/642 be established as the First International Reference Reagent for Pertussis Antiserum, mouse, with assigned unitages 16 units of anti-PT per vial, 143 units of anti-FHA per vial and 30 units of anti-PRN per vial based on its calibration in terms of US Lot 1. These unitages are also consistent with calibration of 97/642 in terms of the Japanese preparations JNIH-11 for anti-FHA and of JNIH-12 for anti-PT. Purified antigens for Fim 2 and Fim 3 are not readily available and an arbitrary value of 32 units per vial is suggested for anti-Fim 2 and 3 mixture. These recommendations were agreed by the Expert Committee on Biological Standardization of the World Health Organization.

Efficient double-clad thulium-doped fiber laser with a ring cavity

We have constructed a novel ring cavity for a double-clad thulium-doped fiber laser, by placing the fiber's 45 degrees angle-polished output end before the input end and relaunching the pump and the laser power into the fiber. This design can reduce reabsorption by using short fibers without loss of pump efficiency. The dependence of the laser's performance on the fiber's length and the output coupler's reflectivity is investigated experimentally and theoretically. With an 80-cm-long fiber, 2.7-W single-mode continuous-wave output is generated for 11.5 W of launched pump power.

Methylenetetrahydrofolate reductase polymorphisms increase risk of esophageal squamous cell carcinoma in a Chinese population

Methylenetetrahydrofolate reductase (MTHFR) plays a central role in folate metabolism that affects DNA methylation and synthesis. Because germ-line mutations at nucleotides 677 (C-->T) and 1298 (A-->C) in the MTHFR gene cause diminished enzyme activity, and aberrant DNA methylation is oncogenic, we examined the relationship between these two MTHFR polymorphisms and susceptibility to esophageal squamous cell carcinoma (ESCC) in 240 ESCC cases and 360 age- and sex-matched controls in northern CHINA: We found that the allele frequency of MTHFR 677T was significantly higher among cases than among controls (63% versus 41%, P < 0.001). Subjects with the 677TT genotype had a more than 6-fold increased risk of developing ESCC [adjusted odds ratio (OR), 6.18; 95% confidence interval (CI), 3.32-11.51] compared with those who had the 677CC genotype. Furthermore, the elevated ESCC risk associated with the 677 polymorphism was in an allele-dose relationship (trend test, P = 0.0001) with ORs of 1.00, 3.14 (95% CI, 1.94-5.08), and 6.18 (95% CI, 3.32-11.51) for the CC, CT, and TT genotype, respectively, after adjustment for age, sex, smoking status, and the MTHFR 1298 polymorphism. The allele frequency for the MTHFR 1298C was 14% among cases and 17% among controls. The 1298CC genotype was extremely rare in both controls (1.4%) and cases (2.9%) and was also associated with an elevated risk of ESCC (adjusted OR, 4.43; 95% CI, 1.23-16.02) compared with the 1298AA genotype, whereas the 1298AC genotype had no effect on the risk of ESCC. Thus, our findings support the hypothesis that genetic polymorphisms in the MTHFR gene may contribute to susceptibility to carcinogenesis of the esophagus in the at-risk Chinese population.

Prevention of ischemic ventricular tachycardia of Purkinje origin: role for alpha(2)-adrenoceptors in Purkinje?

Recent studies have shown the presence of postjunctional alpha(2)-adrenergic receptors on canine Purkinje fibers but not muscle cells. Stimulation of these receptors results in prolongation of the action potential duration and the Purkinje relative refractory period. We studied the effect of alpha(2)-adrenergic agonists on inducible ischemic ventricular tachycardia (VT) of both Purkinje fiber and myocardial origin. Open-chest dogs in whom VT was induced with extrastimuli after occlusion of the anterior descending coronary artery were studied. A mapping system, incorporating Purkinje signals, characterized the mechanisms of VT. The alpha(2)-adrenergic agonists clonidine (0.5-4.0 microg/kg) or UK 14,304 (4-5 microg/kg) versus saline were given intravenously after reproducibility of inducible sustained monomorphic VT had been demonstrated. Eighteen dogs were given clonidine, eleven of which had focal Purkinje VT. Of these 11 dogs, clonidine blocked VT induction in 9 (81.9%) and rendered VT nonsustained in 1 (9.1%), and VT remained inducible in 1 dog (9.1%), although this was focal midmyocardial VT only. In the seven dogs with VT of myocardial origin, six (85.6%) remained inducible with clonidine, whereas one dog (14.4%) had only nonsustained VT after clonidine. Of the six dogs, UK 14,304 blocked VT induction in four (66.6%) and rendered VT nonsustained in one (16.7%), and VT remained inducible in one dog (16.7%). In four dogs with VT of myocardial origin, VT remained inducible. In the eight control dogs that were given saline, focal Purkinje VT was repeatedly inducible. Pharmacological stimulation of postjunctional alpha(2)-adrenoceptors on Purkinje fibers may selectively prevent induction of VT of Purkinje fiber origin in the ischemic canine ventricle.

[The effect of culture conditions on the fatty acid composition in the mycelium of the Cephalosporium sp]

The optimal condition of Cephalosporium sp. to culture mycelia and accumulate polyunsaturated fatty acid (PUFA) was researched. The optimal culture condition to get mycelium productivity was: maltose 60 g/L, KNO3 3 g/L, initial pH 6.0, 100 mL medium in 500 mL flask, seeding 25% (v/v), 25 degrees C culture it for 10 days. The optimal condition to accumulation PUFA proportion to total fatty acid was: glucose 10-20 g/L, NH4Cl or (NH4)2SO4 3 g/L, initial pH 4.0, 100 mL medium in 500 mL falsk, seeding 10-20% (v/v) and lighted it when it was cultured. It was suggested that two step could be used in the producing progress. A proposal was put forward that the oileic acid transformed to linoleic acid was the key step to produce PUFA. This proposal gave a base to research the optimal culture condition and enzyme regulation.

Myocardial ischemia-reperfusion damage impacts occurrence of ventricular fibrillation in dogs

To define the relationship between ischemia-reperfusion-induced myocardial damage (IRD) and the occurrence of ventricular tachycardia (VT) and fibrillation (VF), we studied 23 dogs with a three-dimensional activation mapping system. Left anterior descending (LAD) coronary artery occlusion and reperfusion were performed while recording electrograms during VF and atrial pacing. Prior nonischemic sites showing IRD, defined as at least 10% loss of electrogram voltage after reperfusion, had the longest ventricular effective refractory periods (ERPs). IRD sites also occurred more frequently in dogs with reperfusion VF (44 +/- 2 sites, P < 0.01) compared with dogs with VT (18 +/- 5 sites) and no VT (16 +/- 3 sites). In dogs (n = 3) with 3 h of reperfusion, 95% of IRD sites still had lower voltage than those recorded during occlusion. Activation mapping of the first eight complexes of VF had Purkinje or endocardial focal origin in 57%, and complexes originated from IRD sites in 28%. In contrast, dogs with only reperfusion VT also had Purkinje or endocardial focal origin in 79%, but only 5% (P < 0.01 vs. VF dogs) of the sites of origin had IRD. Therefore, dogs with reperfusion VF had more IRD sites where the ERP was longest, and more focal ventricular complexes originated from IRD sites, indicating that IRD may be one important factor in the occurrence of VF during reperfusion.

CYP 1A1 polymorphism and risk of lung cancer in relation to tobacco smoking: a case-control study in China

The impact of genetic polymorphisms in CYP1A1 on susceptibility to lung cancer has received particular interest in recent years since this enzyme plays a central role in activation of major classes of tobacco carcinogens. Several polymorphisms in the CYP1A1 locus have been identified and their genotypes appear to exhibit population frequencies that depend on ethnicity. We have assessed the role of CYP1A1 genotype in lung cancer risk in the Chinese population via a case-control study. Three polymorphisms, m1 (MSP:I), m2 (exon 7 Ile-->Val) and m4 (exon 7 Thr-->Asn), were determined by PCR-RFLP in 404 controls and 217 lung cancer cases. While no polymorphic alleles were detectable in the m4 site among our study subjects, the allele frequencies for CYP1A1 m1 and CYP1A1 m2 were found to be 35.6 and 25.6% among controls, compared with 42.6 and 34.2% among cases. Multivariate analysis showed an elevated risk for lung cancer in subjects having at least one m1 allele [odds ratio (OR) = 2.0, 95% confidence interval (CI) = 1.4-2.8] or having at least one m2 allele (OR = 1.9, 95% CI = 1.3-2.7). However, this increased risk was limited to squamous cell carcinoma (SCC), but not adenocarcinoma or other histological types of lung cancer. Stratified analysis indicated a multiplicative interaction between tobacco smoking and variant CYP1A1 m1 genotypes on the risk of SCC. The ORs of SCC for the variant CYP1A1 m1 genotype, tobacco smoking and both factors combined were 2.8, 9.1 and 29.9, respectively. When the data was stratified by the pack-year values, this joint effect was consistent and stronger among the heaviest smokers. The interaction between tobacco smoking and the variant CYP1A1 m2 genotypes followed the same pattern. Our findings support the conclusion that CYP1A1 m1 and CYP1A1 m2 polymorphisms are associated with smoking-related lung cancer risk in Chinese.

[Genetic polymorphism in hOGG1 and susceptibility to esophageal cancer in Chinese]

OBJECTIVE

To examine the association between Ser326Cys polymorphism in hOGG1 gene, which is involved in the repair of 8-hydroxyguanine in damaged DNA, and investigate the risk of squamous cell carcinoma of the esophagus in Chinese.

METHODS

Ser326Cys polymorphism in hOGG1 gene was determined by PCR-SSCP approach among 201 normal controls and 196 patients with squamous cell carcinoma of the esophagus. The association between this genetic polymorphism and the risk of the cancer was examined by a multivariate analysis.

RESULTS

The Cys/Cys genotype of hOGG1 was found in 21.4% of patients with the cancer and in 13.4% of controls (P<0.05). Homozygosity for the Cys/Cys genotype significantly increased the risk of developing esophageal cancer, with the odds ratio adjusted for age, sex and smoking being 1.9(95% CI 1.3-2.6). Smoking also significantly increased esophageal cancer risk in this case-control study (adjusted OR 2.6; 95% CI 1.7- 3.9). No interaction between smoking and Cys/Cys genotype was observed for the risk of esophageal cancer.

CONCLUSION

Polymorphism of hOGG1 Ser326Cys may play a role in esophageal carcinogenesis.

Investigation of an aerosol challenge model as alternative to the intracerebral mouse protection test for potency assay of whole cell pertussis vaccines

The current potency test for whole cell pertussis vaccines, the intracerebral mouse protection test, is still the only assay which has shown a correlation with protection in children. However, it has considerable disadvantages as it uses a severe challenge procedure and the results tend to show significant intra- and inter-laboratory variation. An alternative assay based on non-lethal aerosol challenge of mice has been investigated as a replacement for the current intracerebral mouse protection test. Evaluation of this indicated that the aerosol system allowed consistent inoculation of bacteria into mice and gave good reproducibility. The protective capacity of different vaccine preparations was distinguished by this assay. Furthermore, the viable counts of Bordetella pertussis in the lungs of challenged mice were immunisation dose-dependent, which allowed the relative potency of vaccines to be calculated. Comparison of potency of five batches of vaccine from different manufacturers assayed by both the intracerebral and the aerosol challenge methods ranked the vaccines in identical order. The results suggest that this method has potential for use as a potency test for whole cell pertussis vaccine which would result in a great reduction in the number of animals used. It would also replace the lethal challenge by a non-lethal procedure and thereby avoid the use of the severe intracerebral challenge procedure.

Transcriptional effects on double-strand break-induced gene conversion tracts

Transcription stimulates spontaneous homologous recombination, but prior studies have not investigated the effects of transcription on double-strand break (DSB)-induced recombination in yeast. We examined products of five ura3 direct repeat substrates in yeast using alleles that were transcribed at low or high levels. In each strain, recombination was stimulated by DSBs created in vivo at an HO site in one copy of ura3. Increasing transcription levels in donor or recipient alleles did not further stimulate DSB-induced recombination, nor did it alter the relative frequencies of conversion and deletion (pop-out) events. This result is consistent with the idea that transcription enhances spontaneous recombination by increasing initiation. Gene conversion tracts were measured using silent restriction fragment length polymorphisms (RFLPs) at approximately 100bp intervals. Transcription did not alter average tract lengths, but increased transcription in donor alleles increased both the frequency of promoter-proximal (5') unidirectional tracts and conversion of 5' markers. Increased transcription in recipient alleles increased the frequency of bidirectional tracts. We demonstrate that these effects are due to transcription per se, and not just transcription factor binding. These results suggest that transcription influences aspects of gene conversion after initiation, such as strand invasion and/or mismatch repair (MMR).

[Expression of T cell factor 4 in renal cell carcinoma]

OBJECTIVE

To investigate of the transduction of Wnt/Frizzled pathway in nuclei and the function of TCF4 (T Cell Factor) in renal cell carcinoma.

METHODS

TCF4 mRNA are tested through RT-PCR and Northern Blot in renal cancer tissue and renal cancer cell strain (GRC-I).

RESULTS

It has been certificated that TCF4 are expressed in renal cell carcinoma, at the same time, there are some different splice of TCF4 in renal cancer. A new 300bp mutant gene are found.

CONCLUSION

TCF4, an important molecular of Wnt/Frizzled pathway, takes part in the formation and progression of renal cell carcinoma, different splice of TCF4 is one of the mechanism.

Somatic embryogenesis of Echinodorus orisis L. and the kinetic changes of the endogenous hormones contents during the embryogenetic process

Somatic embryogenesis was achieved in young Leaf cuttings of Echinodorus orisis L., an aquatic ornamental plant, in a short period (25 days). Among the cytokinins and their combinations tested, 6-BA (1 mg/L) and Zt (1 mg/L) in MS medium induced the highest efficiency (100%) of somatic embryogenesis, with a maximum of 4.87 embryoids per explant. Roots instead of somatic embryos were formed when NAA (0.5 mg/L) was added to MS medium containing Zt (1 mg/L). Matured embryoids were germinated and rooted in MS medium with IAA (1 mg/L) after 5 days cultivation. Seventy-two percent of the rooted plantlets transplanted survived in the aquarium. The endogenous hormone contents in various stages of somatic embryogenetic process were measured by HPLC. The concentrations of all the hormones tested were about 2 times that of the cuttings from the untreated fresh leaves after 10 days incubation. Meanwhile, the concentration of IAA presents two peaks after 10 and 25 days of cultivation, respectively. The cytokinin (Zt and ZR) peak, about 8 times more than CK, appeared in 15 days cultivation when the heart-shaped embryos formed. The fluctuation of the GA3 concentration was very similar to that of cytokinin. The ABA, however, remains stable at quite high concentration after 10 days of cultivation.

Synthesis, biodistribution, and primate imaging of fluorine-18 labeled 2beta-carbo-1'-fluoro-2-propoxy-3beta-(4-chlorophenyl)tr opanes. Ligands for the imaging of dopamine transporters by positron emission tomography

2beta-(R)-Carbo-1-fluoro-2-propoxy-3beta-(4-chlorophenyl) tro pane ((R)-FIPCT, R-6) and 2beta-(S)-carbo-1-fluoro-2-propoxy-3beta-(4-chlorophenyl) tro pane ((S)-FIPCT, S-6) were prepared and evaluated in vitro and in vivo for dopamine transporter (DAT) selectivity and specificity. High specific activity [(18)F](R)-FIPCT and [(18)F](S)-FIPCT were synthesized in 5% radiochemical yield (decay-corrected to end of bombardment (EOB)) by preparation of the precursors 2beta-carbo-R-1-mesyloxy-2-propoxy-3beta-(4-chlorop hen yl)tropane (R-12) and 2beta-carbo-S-1-mesyloxy-2-propoxy-3beta-(4-chlorop hen yl)tropane (S-12) followed by treatment with no carrier-added potassium[(18)F]fluoride and kyrptofix K222 in acetonitrile. Competition binding in cells stably expressing the transfected human DAT and serotonin transporter (SERT) labeled by [(3)H]WIN 35428 and [(3)H]citalopram, respectively, demonstrated the following order of DAT affinity (K(i) in nM): GBR 12909 (0.36) > CIT (0.48) > (S)-FIPCT (0.67) >> (R)-FIPCT (3.2). The affinity of (S)-FIPCT and (R)-FIPCT for SERT was 127- and 20-fold lower, respectively, than for DAT. In vivo biodistribution studies were performed in male rats and demonstrated that the brain uptake of [(18)F](R)-FIPCT and [(18)F](S)-FIPCT were selective and specific for DAT rich regions (caudate and putamen). PET brain imaging studies in monkeys demonstrated high [(18)F](R)-FIPCT and [(18)F](S)-FIPCT uptake in the caudate and putamen which resulted in caudate-to-cerebellum and putamen-to-cerebellum ratios of 2.5-3.5 at 115 min. [(18)F](R)-FIPCT uptake in the caudate/putamen achieved transient equilibrium at 75 min. In an imaging experiment with [(18)F](S)-FIPCT in a rhesus monkey with its left hemisphere lesioned with MPTP, radioactivity was reduced to background in the caudate and putamen of the lesioned hemisphere. The high specific activity one-step radiolabeling preparation and high specificity and selectivity of [(18)F](R)-FIPCT and [(18)F](S)-FIPCT for DAT indicate [(18)F](R)-FIPCT and [(18)F](S)-FIPCT are potential radioligands for mapping brain DAT in humans using PET.

18F-labeled FECNT: a selective radioligand for PET imaging of brain dopamine transporters

Fluorine-18 labeled 2beta-carbomethoxy-3beta-(4-chlorophenyl)-8-(2-fluoroethyl)nort ropane (FECNT) was synthesized in the development of a dopamine transporter (DAT) imaging ligand for positron emission tomography (PET). The methods of radiolabeling and ligand synthesis of FECNT, and the results of the in vitro characterization and in vivo tissue distribution in rats and in vivo PET imaging in rhesus monkeys of [18F]FECNT are described. Fluorine-18 was introduced into 2beta-carbomethoxy-3beta-(4-chlorophenyl)-8-(2-fluoroethyl)nort ropane (4) by preparation of 1-[18F]fluoro-2-tosyloxyethane (2) followed by alkylation of 2beta-carbomethoxy-3beta-(4-chlorophenyl)nortropane (3) in 21% radiochemical yield (decay corrected to end of bombardment [EOB]). Competition binding in cells stably expressing the transfected human DAT serotonin transporter (SERT) and norepinephrine transporter (NET) labeled by [3H]WIN 35428, [3H]citalopram, and [3H]nisoxetine, respectively, indicated the following order of DAT affinity: GBR 12909 > CIT >> 2beta-carbomethoxy-3beta-(4-chlorophenyl)-8-(3-fluoropropyl) nortropane (FPCT) > FECNT. The affinity of FECNT for SERT and NET was 25- and 156-fold lower, respectively, than for DAT. Blocking studies were performed in rats with a series of transporter-specific agents and demonstrated that the brain uptake of [18F]FECNT was selective and specific for DAT-rich regions. PET brain imaging studies in monkeys demonstrated high [18F]FECNT uptake in the caudate and putamen that resulted in caudate-to-cerebellum and putamen-to-cerebellum ratios of 10.5 at 60 min. [18F]FECNT uptake in the caudate/putamen peaked in less than 75 min and exhibited higher caudate- and putamen-to-cerebellum ratios at transient equilibrium than reported for 11C-WIN 35,428, [11C]CIT/RTI-55, or [18F]beta-CIT-FP. Analysis of monkey arterial plasma samples using high performance liquid chromatography determined that there was no detectable formation of lipophilic radiolabeled metabolites capable of entering the brain. In equilibrium displacement experiments with CIT in rhesus monkeys, radioactivity in the putamen was displaced with an average half-time of 10.2 min. These results indicate that [18F]FECNT is a radioligand that is superior to 11C-WIN 35,428, [11C]CIT/RTI-55, [18F]beta-CIT-FP, and [18F]FPCT for mapping brain DAT in humans using PET.

Development of a nitric oxide induction assay as a potential replacement for the intracerebral mouse protection test for potency assay of pertussis whole cell vaccines

The intracerebral mouse protection test (Kendrick test) for the potency assay of pertussis vaccines is a complex and time consuming in vivo test which has a significant intra- and interlaboratory variation. Thus, there is a pressing need to develop a replacement for the Kendrick test. There is now convincing evidence to suggest that Bordetella pertussis can be taken up and survive within macrophages in the lungs and that cell-mediated immunity plays a role in protection. It was hypothesised that murine macrophages could be activated by immunisation with whole cell pertussis vaccines and therefore induce NO production. An alternative in vitro assay based on the determination of reactive nitrogen intermediates produced as a result of macrophage activation has been examined as a possible replacement for the current intracerebral (i.c.) mouse protection test. NO induction was studied in the peritoneal macrophages of female NIH mice immunised with normal and denatured whole cell B. pertussis vaccines respectively. Compared with controls receiving diluent only, macrophages and spleen cells from mice immunised with whole cell pertussis vaccine responded in vitro to selected pertussis antigens by NO synthesis. The production of NO in response to in vitro culture with bacterial antigen was immunisation dose dependent and was correlated with protective immunity in vivo as determined by i.c. challenge. The results suggest that NO production may serve as a marker of macrophage activation in mice immunised with whole cell vaccine, and could form the basis of a potential replacement potency assay.

Cortical spreading depression in the gyrencephalic feline brain studied by magnetic resonance imaging

1.Time-lapse diffusion-weighted magnetic resonance imaging (DWI) was used to detect and characterize complex waves of cortical spreading depression (CSD) evoked with KCL placed upon the suprasylvian gyrus of anaesthetized cats. 2. The time-lapse representations successfully demonstrated primary CSD waves that propagated with elliptical wavefronts selectively over the ipsilateral cerebral hemispheres with a velocity of 3.8 +/- 0.70 mm min(-1) (mean +/- S.E.M. of 5 experiments). 3. In contrast, the succeeding secondary waves often remained within the originating gyrus, were slower (velocity 2.0 +/- 0.18 mm min(-1), more fragmented and varied in number. 4. Computed traces of the apparent diffusion coefficients (ADCs) showed negative deflections followed by monotonic decays (amplitudes: primary wave, -19.9 +/- 2.8%; subsequent waves, -13.6 +/- 1.9% duration at half-maximal decay, 150-200 s) when determined from regions of interest (ROIs) through which both primary and succeeding CSD waves propagated. 5. The passage of both the primary and the succeeding waves often correlated with transient DC potential deflections recorded from the suprasylvian gyrus. 6. The detailed waveforms of the ADC and the T2*-weighted (blood oxygenation level-dependent: BOLD) traces showed a clear reciprocal correlation. These imaging features that reflect disturbances in cellular water balance agree closely with BOLD measurements that followed the propagation velocities of the first and subsequent CSD events. They also provide a close physiological correlate for clinical observations of cortical blood flow disturbances associated with human migraine.

A study of rotationally invariant and symmetric indices of diffusion anisotropy

This study investigated the properties of a class of rotationally invariant and symmetric (relative to the principal diffusivities) indices of the anisotropy of water self-diffusion, namely fractional anisotropy (FA), relative anisotropy (RA), and volume ratio (VR), with particular emphasis to their measurement in brain tissues. A simplified theoretical analysis predicted significant differences in the sensitivities of the anisotropy indices (AI) over the distribution of the principal diffusivities. Computer simulations were used to investigate the effects on AI image quality of three magnetic resonance (MR) diffusion tensor imaging (DTI) acquisition schemes, one being novel: the schemes were simulated on cerebral model fibres varying in shape and spatial orientation. The theoretical predictions and the results of the simulations were corroborated by experimentally determined spatial maps of the AI in a normal feline brain in vivo. We found that FA mapped diffusion anisotropy with the greatest detail and SNR whereas VR provided the strongest contrast between low- and high-anisotropy areas at the expense of increased noise contamination and decreased resolution in anisotropic regions. RA proved intermediate in quality. By sampling the space of the effective diffusion ellipsoid more densely and uniformly and requiring the same total imaging time as the published schemes, the novel DTI scheme achieved greater rotational invariance than the published schemes, with improved noise characteristics, resulting in improved image quality of the AI examined. Our findings suggest that significant improvements in diffusion anisotropy mapping are possible and provide criteria for the selection of the most appropriate AI for a particular application.