Pharmacological characterization of cis-nitromethylene neonicotinoids in relation to imidacloprid binding sites in the brown planthopper, Nilaparvata lugens

Neonicotinoid insecticides, such as imidacloprid, are selective agonists of the insect nicotinic acetylcholine receptors (nAChRs) and extensively used in areas of crop protection and animal health to control a variety of insect pest species. Here we describe that two cis-nitromethylene neonicotinoids (IPPA152002 and IPPA152004), recently synthesized in our laboratory, discriminated between the high and low affinity imidacloprid binding sites in the brown planthopper, Nilaparvata lugens, a major insect pest of rice crops in many parts of Asia. [(3)H]imidacloprid has two binding sites with different affinities (Kd value of 0.0035 +/- 0.0006 nM for the high-affinity site and 1.47 +/- 0.22 nM for the low-affinity site). Although the cis-nitromethylene neonicotinoids showed low displacement ability (Ki values of 0.15 +/- 0.03 microM and 0.42 +/- 0.07 microM for IPPA152002 and IPPA152004, respectively) against [(3)H]imidacloprid binding, low concentrations (0.01 microM) of IPPA152002 completely inhibited [(3)H]imidacloprid binding at its high-affinity site. In Xenopus oocytes co-injected with cRNA encoding Nlalpha1 and rat beta2 subunits, obvious inward currents were detected in response to applications of IPPA152002 and IPPA152004, although the agonist potency is reduced to that of imidacloprid. The previously identified Y151S mutation in Nlalpha1 showed significant effects on the agonist potency of IPPA152002 and IPPA152004, such as a 75.8% and 70.6% reduction in Imax, and a 2.4- and 2.1-fold increase in EC(50). This data clearly shows that the two newly described cis-nitromethylene neonicotinoids act on insect nAChRs and like imidacloprid, discriminated between high and low affinity binding sites in N. lugens native nAChRs. These compounds may be useful tools to further elucidate the pharmacology and nature of neonicotinoid binding sites.

The lupus-susceptibility gene kallikrein downmodulates antibody-mediated glomerulonephritis

Sle3 is a NZM2410/NZW-derived lupus-susceptibility interval on murine chromosome 7, which is associated with spontaneous lupus nephritis (SLN), and also anti-GBM-induced glomerulonephritis (GN). The tissue kallikrein gene cluster is located within the Sle3 interval and constitutes potential candidate genes for this locus. We have recently reported that renal kallikrein expression was upregulated by anti-GBM antibody challenge in a strain-specific manner and that it was significantly underexpressed in the anti-GBM-sensitive strains, including B6.Sle3. Further sequencing and functional studies reported earlier provided evidence that kallikreins could constitute disease genes in lupus. In this report, we have used an adenoviral vector to deliver the klk1 gene to B6.Sle3 congenics to directly test if kallikreins might have a protective effect against anti-GBM-induced nephritis. Our data show that klk1 gene delivery ameliorated anti-GBM-induced nephritis in B6.Sle3 congenics. Taken together with earlier studies, these findings indicate that kallikreins play an important protective role in autoantibody-initiated GN and could constitute potential candidate genes for anti-GBM-induced GN and SLN.

Cryopreservation of embryogenic callus of Dioscorea bulbifera by vitrification

Cryopreservation of callus of Dioscorea bulbifera by vitrification was optimized. Calli of Dioscorea bulbifera were pretreated in liquid Murashige and Skoog (MS) medium supplemented with 2 mg L(-1) kinetin (KT), 0.5 mg L(-1) NAA, 0.5 mg L(-1) 2,4-D and 0.2 M sucrose for 5 d under continuous light (36 microM m(-2) s(-1)) at 25 + or - 1 degree C. The material was then loaded with 60 percent vitrification solution (PVS2) for 20 min at room temperature and dehydrated with 100 percent PVS2 for 30 min at 0 degree C. After changing the solution with fresh PVS2, the calli were directly immersed in liquid nitrogen and conserved for 1- 360 d. After rapid thawing in a water-bath at 35 degree C, the calli were washed three times with liquid MS medium supplemented with 2 mg L(-1) KT, 0.5 mg L(-1) NAA, 0.5 mg L(-1) 2, 4-D and 1.2 M sucrose and then transferred onto solid MS medium supplemented with KT 2 mg L(-1), NAA 0.5 mg per liter, 0.09 M sucrose and 0.75 percent agar. The cultures were kept in the dark for 2 days prior to exposure to the light (12 h light-dark cycle). The TTC test showed that 80-90 percent of the calli survived this cryoprocedure and there was a 60-70 percent regeneration of plantlets from the calli. The regenerated material did not exhibit any morphological variations.

Serologic evidence for reactivation of cryptococcosis in solid-organ transplant recipients

Cryptococcosis is a significant infection with a high mortality in solid-organ transplant recipients. Nonetheless, the pathogenesis of this disease is poorly understood. It has been hypothesized that cryptococcosis may result from either primary infection or reactivation of a latent infection. Sera were obtained from transplant recipients prior to transplantation and at the time they developed cryptococcosis. Control sera were obtained before and after transplant from patients who did not develop cryptococcosis. Sera were tested for antibodies against Cryptococcus neoformans by using an immunoblot assay. Antibody responses were also compared with those observed in sera from rats with experimental pulmonary cryptococcosis. In all, 52% of the transplant recipients who developed cryptococcosis exhibited serologic evidence of cryptococcal infection before transplantation. These patients developed cryptococcosis significantly earlier after transplant than patients without preexisting reactivity did (5.6 +/- 3.4 months compared to 40.6 +/- 63.8 months, respectively [P = 0.0011]). The results from our study suggest that a substantial proportion of transplant-associated cryptococcosis cases result from the reactivation of a latent infection. These findings also highlight the potential utility of serologic studies in identifying patients at risk for the development of cryptococcosis after transplantation.

Efficient inhibition of multidrug-resistant human tumors with a recombinant bispecific anti-P-glycoprotein × anti-CD3 diabody

Overexpressing of P-glycoprotein (Pgp) has been shown to be responsible for cancer resistance to multiple chemotherapeutic agents. Immunotherapy with biological agents, such as bispecific antibodies (BsAbs), may represent a promising approach to overcome the emergence of drug resistance. Here we constructed a recombinant BsAb, a diabody, with specificities to both CD3 on human T-lymphocyte and Pgp on cancer cells. The diabody was produced in Escherichia coli in a soluble functional form and purified by an affinity chromatography with a yield of >4 mg/l culture medium in shaker flask. The diabody binds to both CD3 on T-lymphocytes and Pgp on multidrug-resistant (MDR) tumor cells with affinities that are comparable to its respective parental single chain Fv molecules. In the presence of activated human peripheral blood lymphocytes (PBLs), the diabody mediates effectively the lysis of the Pgp-overexpressing human leukemia K562/A02 and epidermoid carcinoma KBv(200) cells, but is much less potent in mediating the lysis of the parent K562 and KB cells. Further, the diabody localized selectively within the K562/A02 xenografts in mice. When combined with activated PBL, the diabody significantly inhibited the growth of K562/A02 and KBv(200), but had no effect on K562 and KB xenografts. In contrast, treatment with doxorubicin, a standard chemotherapeutic agent, only inhibited the growth of K562 and KB, but had no effect on K562/A02 and KBv(200) xenografts. Taken together, our results suggest that the anti-Pgp x anti-CD3 diabody may have a great potential in the treatment of various MDR cancers.

Regulatory DNA required for vnd/NK-2 homeobox gene expression pattern in neuroblasts

Vnd/NK-2 protein was detected in 11 neuroblasts per hemisegment in Drosophila embryos, 9 medial and 2 intermediate neuroblasts. Fragments of DNA from the 5'-flanking region of the vnd/NK-2 gene were inserted upstream of an enhancerless betagalactosidase gene in a P-element and used to generate transgenic fly lines. Antibodies directed against Vnd/NK-2 and beta-galactosidase proteins then were used in double-label experiments to correlate the expression of beta-galactosidase and Vnd/NK-2 proteins in identified neuroblasts. DNA region A, which corresponds to the -4.0 to -2.8-kb fragment of DNA from the 5'-flanking region of the vnd/NK-2 gene was shown to contain one or more strong enhancers required for expression of the vnd/NK-2 gene in ten neuroblasts. DNA region B (-5.3 to -4.0 kb) contains moderately strong enhancers for vnd/NK-2 gene expression in four neuroblasts. Hypothesized DNA region C, whose location was not identified, contains one or more enhancers that activate vnd/NK-2 gene expression only in one neuroblast. These results show that nucleotide sequences in at least three regions of DNA regulate the expression of the vnd/NK-2 gene, that the vnd/NK-2 gene can be activated in different ways in different neuroblasts, and that the pattern of vnd/NK-2 gene expression in neuroblasts of the ventral nerve cord is the sum of partial patterns.

[Influence of the hearing loss level and auditory sensation curve type on click evoked SP/AP amplitude ratio in Menière's disease]

OBJECTIVE

To assess the influence of hearing loss level and auditory sensation curve type on click evoked SP/AP amplitude ratio (negative summating potential/action potential) in the diagnosis of Meniere's disease.

METHOD

AP and SP was recorded with tympanic ECochG in normal controls (50 ears), patients with sensorineural hearing loss (SNHL) and patients with Meniere's disease (90 ears) which were further divided based upon the degree of hearing loss and audiometric configuration. SP/AP amplitude ratio was calculated and analyzed.

RESULT

AP latency in the three groups had no significant differences. AP amplitude in normal hearing subjects was higher than other two patients groups (P < 0.05). Amplitude of SP of control group was higher than that of SNHL group (P < 0.01), but lower than Meniere's disease group (P < 0.01). SP/AP amplitude ratio in Meniere's disease ears was (48.09 +/- 14.83)%, which was significantly higher than that of SNHL group (20.20 +/- 15.00)% (P < 0.01) and normal group (23.85 +/- 8.05)% (P < 0.01). In Meniere's disease ears, SP/AP amplitude ratio was positively correlated to pure tone thresholds (r = 0.5601 P < 0.01). An elevated SP/AP ratio was found in 73% of the Meniere's ears and 6% of the SNHL ears. SP/AP ratio among the different levels of hearing loss in Meniere's disease ears, of the ears with mild hearing loss was lower than those with moderate (P < 0.01) and severe hearing loss (P < 0.01), but between later groups there was no statistical significant difference (P > 0.05). Positive rate of SP/AP ratio was 63% in mild, 83% in moderate, 73% in severe hearing loss ears respectively. SP/AP amplitude ratio in patients with low tone auditory curve type was lower than that with flat type(P < 0.05), the latter had no significant difference (P > 0.05) compared with high tone type. Positive rate was 67.57% in low tone type, 75% in high tone type and 78% in flat tone type respectively.

CONCLUSION

Results suggests the increase of SP/AP ratio was of clinical significance in the diagnosis of Meniere's disease, and was with advancing pure tone thresholds in certain range of hearing loss levels. Click evoked SP/AP amplitude ratio was affected by degree of hearing loss and auditory sensation curve as well, perhaps the influence of the former on SP/AP ratio was considerable significant.

Testicular protein Spag5 has similarity to mitotic spindle protein Deepest and binds outer dense fiber protein Odf1

Outer dense fibers (ODF) and the fibrous sheath (FS) are major cytoskeletal structures in the mammalian sperm tail. The molecular mechanisms underlying their morphogenesis along the axoneme or their function are poorly understood. Recently, we reported the cloning and characterization of Odf2, a major ODF protein, and Spag4, an axoneme-binding protein, by virtue of their strong interaction with Odf1, the 27 kDa major ODF protein. We proposed a crucial role for leucine zippers in molecular interactions during sperm tail morphogenesis. Here we report the cloning and characterization of a novel gene, Spag5, which encodes a 200 kDa testicular protein that interacts strongly with Odf1. Spag5 is transcribed and translated in pachytene spermatocytes and spermatids. It bears 73% similarity with the mitotic spindle protein Deepest of unknown function. We identified two putative leucine zippers in the C-terminal part of the Spag5 protein, the downstream one of which is involved in interaction with Odf1. Interestingly, these motifs are present in Deepest. These results highlight the importance of the leucine zipper in sperm tail protein interactions. Mol. Reprod. Dev. 59: 410-416, 2001.

A study on the detection of weak photoacoustic signals by stochastic resonance

On the basis of stochastic resonance (SR) theory a study of the detection of photoacoustic (PA) signals without a lock-in amplifier is presented. The applicability of the SR method is investigated both with simulated signals calculated by use of a Gaussian model and with experimental PA signals. Signal-to-noise ratio (SNR) is improved substantially by adjusting the properties of a non-linear system to realize SR. By use of this method the lock-in amplifier can be removed from a PA spectrometer.

[Study of specific targeting cytotoxicity mediated by anti-CD(3)/anti-CD(20) Diabody]

OBJECTIVE

To study the specific targeting cytotoxicity mediated by an anti-CD(3)/anti-CD(20) diabody.

METHODS

The diabody was purified by affinity chromatography and identified by Western blot assay, size exclusion chromatography, FACS and rosetting assay; the effect of the anti-CD(3)/anti-CD(20) diabody mediated lysis of CD(20)-expressing tumor cells was assayed by (51)Cr release assay in vitro and by human B cell tumor nude mice xenograft model in vivo.

RESULTS

The anti-CD(3)/anti-CD(20) diabody could bind both Jurkat cells (CD(3)(+)) and Daudi cells (CD(20)(+)) and appeared to be potent in targeting activated peripheral blood mononuclear cell (PBMC) to lyse Daudi cells in vitro. Furthermore, it inhibited tumor growth and prolonged the survival of mice bearing xenografted Raji cells.

CONCLUSION

The diabody proved to be a potent agent for targeting peripheral blood lymphocytes to lyse CD(20) antigen expressing tumor cells in vitro and in vivo.

A two-dimensional immune algorithm for resolution of overlapping two-way chromatograms

A two-dimensional immune algorithm is proposed for resolving the multicomponent overlapping two-way data matrices. The method is a development of the one-dimensional immune algorithm proposed elsewhere. When the inner product of vectors is expanded to the similar operation on matrices, the 1D immune algorithm can be expanded to the 2D algorithm which is suitable for the analysis of two-way data matrices. Both simulated and experimental two-way data sets were investigated by the method, and the results prove that the 2D immune algorithm is an effective tool for resolving the overlapping two-way signals. The effect of noise on the recoveries is also discussed.

[The mutation of anti-CD3 antibody (HIT3a) gene and its expression]

OBJECTIVE

To improve the expression of anti-CD(3) single chain Fv (scFv) by site mutation and identify its biological activity.

METHODS

Anti-CD(3) scFv gene was mutated by PCR, the target clones were screened by both the fingerprints of DNA restriction endonuclease digestion and Western blot, the antigen-binding activity of scFv was examined by FACS, competitive inhibition was performed with (125)I-labeled HIT3a and the cytotoxic effect mediated by the anti-CD(3) scFv-activated T lymphocytes was analyzed by (51)Cr-released assays.

RESULTS

The DNA sequencing showed that the 6th amino acid of the anti-CD(3) antibody (HIT3a) heavy chain gene was mutated from E (GAG) to Q (CAG). The expression of mutated anti-CD(3) scFv (m2) was increased by 100 times higher than that of the parent scFv, and there was no difference in the Jurkat cell (CD(3)(+))-binding activity between the (m2) and parent scFv. The preliminary results of competitive assays showed that m2 could partially block the sites of CD(3)(+) Jurkat cells where the parent antibody bound to. Cytotoxicity assays demonstrated that CD(3)AK cells induced by IL-2 and m2 showed stronger cytotoxic effect than that of LAK cells induced by IL-2 alone in vitro.

CONCLUSION

By site mutation, a high expression fragment m2 of anti-CD(3) scFv antibody was obtained. The results of some experiments indicated that m2 could bind to CD(3)(+) Jurkat cells, furthermore, by co-stimulated with IL-2, it could activate peripheral T lymphocytes and induce CD(3)AK cytotoxic effect.

A monoclonal antibody specific for human thymidine kinase 1

Previous research has shown that thymidine kinase 1 (TK1), a nucleotide salvage pathway enzyme, is an accurate prognostic and diagnostic tumor marker. However, the current radioisotope assay for TK1 is cumbersome and has hampered the clinical application of this diagnostic technique in cancer management. To overcome the problems of the current radioisotope assay, we have produced monoclonal antibodies (MAbs) using purified TK1 from Raji cell extract. Production and confirmation of their specificity was confirmed using Western blot, immunohistochemical staining, TK1 activity inhibition assays, and enzyme-linked immunoadsorbent assay (ELISA) techniques. Thus, in the future, these antibodies may aid in the early detection of cancer and more accurate prognosis, as well as allowing for an increased ability to study the function of TK1 in basic cellular processes.

Signal estimation and denoising using VC-theory

Signal denoising is closely related to function estimation from noisy samples. The same problem is also addressed in statistics (non-linear regression) and neural network learning. Vapnik-Chervonenkis (VC) theory has recently emerged as a general theory for estimation of dependencies from finite samples. This theory emphasizes model complexity control according to Structural Risk Minimization (SRM) inductive principle, which considers a nested set of models of increasing complexity (called a structure), and then selects an optimal model complexity providing minimum error for future samples. This paper applies the framework of VC-theory to signal estimation/denoising. There are three factors important for accurate signal estimation from finite samples: (1) the type of (orthogonal) basis functions used (i.e. Fourier basis, wavelets etc.). (2) The choice of a structure, i.e. ordering of the basis functions according to their 'importance' for accurate signal estimation. This corresponds to the choice of a 'structure' under SRM formulation. (3) Selecting an optimal number of terms (basis functions) from the ordered sequence of basis functions (2), aka model selection or complexity control (in statistics). We propose a methodology for specifying appropriate orderings (2) and an analytic expression for model selection (3) for signal processing applications. We also present empirical comparisons between the proposed methodology and current state-of-the-art wavelet thresholding methods for univariate signals. These comparisons suggest that the prudent choice of a structure (2) and the use of VC-based model selection (3) are critical for accurate signal estimation with finite samples.

Indole-3-glycerol phosphate, a branchpoint of indole-3-acetic acid biosynthesis from the tryptophan biosynthetic pathway in Arabidopsis thaliana

The phytohormone indole-3-acetic acid (IAA) plays a vital role in plant growth and development as a regulator of numerous biological processes. Its biosynthetic pathways have been studied for decades. Recent genetic and in vitro labeling evidence indicates that IAA in Arabidopsis thaliana and other plants is primarily synthesized from a precursor that is an intermediate in the tryptophan (Trp) biosynthetic pathway. To determine which intermediate(s) acts as the possible branchpoint for the Trp-independent IAA biosynthesis in plants, we took an in vivo approach by generating antisense indole-3-glycerol phosphate synthase (IGS) RNA transgenic plants and using available Arabidopsis Trp biosynthetic pathway mutants trp2-1 and trp3-1. Antisense transgenic plants display some auxin deficient-like phenotypes including small rosettes and reduced fertility. Protein gel blot analysis indicated that IGS expression was greatly reduced in the antisense lines. Quantitative analyses of IAA and Trp content in antisense IGS transgenic plants and Trp biosynthetic mutants revealed striking differences. Compared with wild-type plants, the Trp content in all the transgenic and mutant plants decreased significantly. However, total IAA levels were significantly decreased in antisense IGS transgenic plants, but remarkably increased in trp3-1 and trp2-1 plants. These results suggest that indole-3-glycerol phosphate (IGP) in the Arabidopsis Trp biosynthetic pathway serves as a branchpoint compound in the Trp-independent IAA de novo biosynthetic pathway.

[Precise map of allelic loss on chromosome 3p14 in nasopharyngeal carcinoma]

OBJECTIVE

To determine the precise allelic loss on chromosome 3p14 and discuss the possible relations between loss of heterozygosity (LOH) and EBV infection, clinical stage and clinic-pathology of nasopharyngeal carcinoma (NPC).

METHODS

Six high dense microsatellite marker on chromosome 3p14 were selected to examine LOH in 32 cases of NPC.

RESULTS

23 of 32 (71.9%) tumors were deleted for at least one locus of six loci. High frequencies of LOH (> 40%) were observed at loci D3S1300(50.0%), D3S1313(46.4%) and D3S1312(44.4%). 12 cases showed LOH in one contiguous and nonrandom region. The smallest common deletion region seems likely to lie between D3S1313 and D3S1312. Relations between LOH on 3p14 and clinical stage and EBV infection were observed. The frequency of LOH was 70.0% in 30 cases of poor-differentiated squamous cell carcinoma. 2 cases of vesicular nucleus cell carcinoma had LOH at two loci.

CONCLUSION

The high deletion rate on 3p14 in NPC indicates that there might be a putative tumor suppressor gene related to the development and progression of NPC.

Bisulfite-containing propofol: is it a cost-effective alternative to Diprivan for induction of anesthesia?

Propofol (Diprivan(TM); AstraZeneca, Wilmington, DE) is a commonly used drug for the induction of general anesthesia in the ambulatory setting. With the availability of a new bisulfite-containing generic formulation of propofol, questions have arisen regarding its cost effectiveness and safety compared with Diprivan(TM). Two hundred healthy outpatients were randomly assigned, according to a double-blinded protocol, to receive either Diprivan(TM) or bisulfite-containing propofol 1.5 mg/kg IV as part of a standardized induction sequence. Maintenance of anesthesia consisted of either desflurane (4%-8% end-tidal) or sevoflurane (1%-2% end-tidal) in combination with a remifentanil infusion (0.125 microg x kg(-1) x min(-1) IV). Patient assessments included pain on injection, induction time, hemodynamic and bispectral electroencephalographic changes during induction, emergence time, and incidence of postoperative nausea and vomiting. The two propofol groups were comparable demographically, and the induction times and bispectral index values during the induction were also similar. However, the bisulfite-containing formulation was associated with less severe pain on injection (5% vs 11%), with fewer patients recalling pain on injection after surgery (38% vs. 51%, P<0.05). None of the patients manifested allergic-type reactions after the induction of anesthesia. The acquisition cost (average wholesale price in US dollars) of a 20-mL ampoule of Diprivan(TM) was $15 compared with $13 for the bisulfite-containing propofol formulation. Therefore, we concluded that the bisulfite-containing formulation of propofol is a cost-effective alternative to Diprivan(TM) for the induction of outpatient anesthesia.

IMPLICATIONS

Bisulfite-containing propofol and Diprivan(TM) (AstraZeneca, Wilmington, DE) were similar with respect to their induction characteristics; however, the generic formulation was associated with a smaller incidence of injection pain. Assuming that the drug costs are similar, these data suggest that the bisulfite-containing formulation of propofol is a cost-effective alternative to Diprivan(TM).