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Antibodies are considered highly specific therapeutic agents in cancer medicines, and numerous formats have been developed. Among them, bispecific antibodies (BsAbs) have gained a lot of attention as a next-generation strategy for cancer therapy. However, poor tumor penetration is a major challenge because of their large size and thus contributes to suboptimal responses within cancer cells. On the other hand, affibody molecules are a new class of engineered affinity proteins and have achieved several promising results with their applications in molecular imaging diagnostics and targeted tumor therapy. In this study, an alternative format for bispecific molecules was constructed and investigated, named ZLMP110-277 and ZLMP277-110, that targets Epstein-Barr virus latent membrane protein 1 (LMP1) and latent membrane protein 2 (LMP2). Surface plasmon resonance (SPR), indirect immunofluorescence assay, co-immunoprecipitation, and near-infrared (NIR) imaging clearly demonstrated that ZLMP110-277 and ZLMP277-110 have good binding affinity and specificity for both LMP1 and LMP2 in vitro and in vivo. Moreover, ZLMP110-277 and ZLMP277-110, especially ZLMP277-110, significantly reduced the cell viability of C666-1 and CNE-2Z as compared to their monospecific counterparts. ZLMP110-277 and ZLMP277-110 could inhibit phosphorylation of proteins modulated by the MEK/ERK/p90RSK signaling pathway, ultimately leading to suppression of oncogene nuclear translocations. Furthermore, ZLMP110-277 and ZLMP277-110 showed significant antitumor efficacy in nasopharyngeal carcinoma-bearing nude mice. Overall, our results demonstrated that ZLMP110-277 and ZLMP277-110, especially ZLMP277-110, are promising novel prognostic indicators for molecular imaging and targeted tumor therapy of EBV-associated nasopharyngeal carcinoma.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has been an unprecedented public health disaster in human history, and its spike (S) protein is the major target for vaccines and antiviral drug development. Although widespread vaccination has been well established, the viral gene is prone to rapid mutation, resulting in multiple global spread waves. Therefore, specific antivirals are needed urgently, especially those against variants. In this study, the domain of the receptor binding motif (RBM) and fusion peptide (FP) (amino acids [aa] 436 to 829; denoted RBMFP) of the SARS-CoV-2 S protein was expressed as a recombinant RBMFP protein in Escherichia coli and identified as being immunogenic and antigenically active. Then, the RBMFP proteins were used for phage display to screen the novel affibody. After prokaryotic expression and selection, four novel affibody molecules (Z14, Z149, Z171, and Z327) were obtained. Through surface plasmon resonance (SPR) and pseudovirus neutralization assay, we showed that affibody molecules specifically bind to the RBMFP protein with high affinity and neutralize against SARS-CoV-2 pseudovirus infection. Especially, Z14 and Z171 displayed strong neutralizing activities against Delta and Omicron variants. Molecular docking predicted that affibody molecule interaction sites with RBM overlapped with ACE2. Thus, the novel affibody molecules could be further developed as specific neutralization agents against SARS-CoV-2 variants.

Nasopharyngeal carcinoma (NPC), is an Epstein-Barr virus (EBV) associated malignancy most common in Southern China and Southeast Asia. In southern China, it is one of the major causes of cancer-related death. Despite improvement in radiotherapy and chemotherapy techniques, locoregional recurrence and distant metastasis remains the major causes for failure of treatment in NPC patients. Therefore, finding new specific drug targets for treatment interventions are urgently needed. Here, we report three potential ZLMP1−C affibody molecules (ZLMP1−C15, ZLMP1−C114 and ZLMP1−C277) that showed specific binding interactions for recombinant and native EBV LMP1 as determined by epitope mapping, co-localization and co-immunoprecipitation assays. The ZLMP1−C affibody molecules exhibited high antitumor effects on NPC-positive cell lines and displayed minimal cytotoxicity towards NPC-negative cell line. Moreover, ZLMP1−C277 showed higher antitumor efficacy than ZLMP1−C15 and ZLMP1−C114 affibody molecules. The ability of ZLMP1−C277 decrease the phosphorylation levels of up-stream activator phospho-Raf-1(Ser338), phospho-MEK1/2(Ser217/Ser221), phospho-ERK1/2(Thr202/Thr204), thereby leading to downstream suppression of phospho-p90RSK(Ser380) and transcription factor c-Fos. Importantly, tumor growth was reduced in tumor-bearing mice treated with ZLMP1−C277 and caused no apparent toxicity. Taken together, our findings provide evidence that ZLMP1−C277 as a promising therapeutic agent in EBV-associated NPC.

Proto-oncoprotein RET (rearranged during transfection) is a receptor tyrosine kinase and belongs to the cadherin superfamily. RET fusion proteins and gatekeeper mutations represent strong cancer drivers involved in the development of a variety of cancers. Although selective RET inhibitors selpercatinib (LOXO-292) and pralsetinib (BLU667) were recently marketed for patients with RET-dependent NSCLC and thyroid cancers, RET solvent front mutations G810R/S/C/V and other secondary mutations such as Y806C/N and V728A have been identified as mechanisms counting for acquired resistance to the two drugs and limits the applications of the kinase inhibitors. To provide novel RET inhibitors effective to a broader spectrum of RET fusions and mutations, we identified TY-1091 as a novel next-generation RET inhibitor through the in-house RET program and systemic screening of RET compound candidates. TY-1091 was characterized for its anti-tumor activity through in vitro and in vivo testing of a variety of RET-dependent tumor models including a panel of 17 engineered RET mutant Ba/F3 cell lines and 2 cancer cell models. The results show that TY-1091 inhibits wild type and major RET mutants (IC50, nM): RET G810S (9.5 nM), RET V804M/L/E (2.8-12.6 nM), and double mutants RET V804M/G810S (23.5 nM) and M918T/G810S (47.0 nM) through a biochemical screening against a panel of 17 engineered RET mutant Ba/F3 cell lines. Importantly, the inhibitory activity of TY-1091 is much higher than that of first-generation RET inhibitor Cabozantinib, and comparable to other second-generation compounds LOXO-292 and BLU-667. Consistent with its mode of action, TY-1091 grants extraordinary inhibition effects to tumor cell proliferation compared to its peer compounds LOXO-292 and BLU-667 (including TT (thyroid cancer, RET C634W) and LC2/ad (NSCLC, CCDC6-RET)), and the inhibition of the RET pathway activation, i.e., inhibition of RET phosphorylation (IC50 < 1 nM), SHC phosphorylation (IC50 = 4.6 nM) and ERK phosphorylation (IC50 = 9.8 nM) in Ba/F3-KIF5B-RET cells further validated the above in vitro phenotype. The therapeutic potential of TY-1091 was then further validated through mouse pharmacology in that TY-1091 demonstrated remarkable anti-tumor efficacy in a variety of xenograft models including Ba/F3 KIF5B-RET (wt), Ba/F3 KIF5B-RET (V804L), TT (thyroid cancer, RET C634W), and LC2/ad (NSCLC, CCDC6-RET). Detailed data will be presented. In summary, TY-1091 is a highly potent, orally available, and safe small molecule inhibitor to pan-RET mutations in cancer, and may attenuate SFMs-mediated resistance to existing RET therapy. The IND clearance from the US FDA was received and Phase I clinical investigations of TY-1091 shall be launched in the US soon. *To Whom Correspondence should be addressed to: Jun Li, Chengshan Niu and Yusheng Wu Citation Format: Chengshan Niu, Maolin Zheng, Huan Wang, Kaige Ji, Meihua Li, Guohui Wang, Rongzhen Ni, Apeng Liang, Aishen Gong, Yazhen Zhang, Hui Su, Mingyu Jiang, Shaoqing Chen, Xiugui Chen, Jun Li, Yusheng Wu. TY-1091, a highly selective and potent second-generation RET inhibitor, demonstrates superior antitumor activity in multiple RET-mutant models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3419.

There is a recognised need for standardisation of protocols for vector genome analysis used in vector manufacturing, to establish dosage, in biodistribution studies and to detect gene doping in sport. Analysis of vector genomes and transgene expression is typically performed by qPCR using plasmid-based calibrants incorporating transgenic sequences. These often undergo limited characterisation and differ between manufacturers, potentially leading to inaccurate quantification, inconsistent inter-laboratory results and affecting clinical outcomes. Contamination of negative samples with such calibrants could cause false positive results. We developed a design strategy for synthetic reference materials (RMs) with modified transgenic sequences to prevent false positives due to cross-contamination. When such RM is amplified in transgene-specific assays, the amplicons are distinguishable from transgene's amplicons based on size and sequence. Using human erythropoietin as a model, we produced certified RM according to this strategy and following ISO Guide 35. Using non-viral and viral vectors, we validated the effectiveness of this RM in vector genome analysis in blood in vitro. The developed design strategy could be applied to production of RMs for other transgenes, genes or transcripts. Together with validated PCR assays, such RMs form a measurement tool that facilitates standardised, accurate and reliable genetic analysis in various applications.

A count of Kekule structures for all 1812 distinct fullerene isomers of C60 shows that 20 isomers surpass the count of 12500 for icosahedral C60, and demonstrates the lack of correlation between molecular-orbital indices of stability and raw Kekule counts for fullerenes. Analysis of Kekule structures in terms of benzenoid, cyclopentenoid and cyclopentadienoid rings reveals the source of the stability of icosahedral C60 in a localised model to be the fact that uniquely amongst the 1812 structural isomers it has a Fries Kekule structure where all hexagons contain three double bonds and all pentagons none.

Genetic fusion of tandem repeats of the complement molecule C3d has been shown to considerably enhance immune responses to genetic vaccines. We have investigated the applicability of this approach to augment humoral immune responses toward vaccines delivered by recombinant adeno-associated virus (AAV) vectors. C3d(3)-fusion was found to markedly decrease antibody responses to merozoite surface protein 4/5 from Plasmodium yoelii and contrasted with greater than 50-fold enhancement in responses when this strategy was similarly applied to another AAV-encoded model antigen, hen egg lysozyme. These data indicate that the efficacy of the C3d(3) strategy operates in an antigen-dependent manner. Additional studies also showed that homologous recombination events between the C3d tandem repeats occurred during vector packaging and transduction resulting in expression of C3d(1)-, C3d(2)-, C3d(3)- and C3d(4)-fused antigen. This is the first report to apply the C3d approach to augment responses against a recombinant viral vector system and the consequences of these findings are discussed.

In catacondensed hexagonal systems, a set of pair-wise resonant hexagons is resonant [Croat. Chem. Acta 56 (1983) 365], [J. Mol. Struct. (Theochem) 279 (1993) 41]. The first proof of this result was given by Hansen and Zheng [J. Mol. Struct. (Theochem) 279 (1993) 41]. Here we offer an alternative proof.

Peripheral nervous system (PNS) sensory neurons are directly involved in the pathophysiology of a number of debilitating inherited and acquired neurological conditions. The lack of effective treatments for many such conditions provides a strong rationale for exploring novel therapeutic approaches, including gene therapy. Friedreich ataxia (FRDA), a sensory neuropathy, is a progressive neurodegenerative disease associated with a loss of large sensory neurons from the dorsal root ganglia. Because a mouse model for this well-characterized disease has been generated, we elected to use FRDA as a model disease. In previous studies we achieved efficient and sustained delivery of a reporter gene to PNS sensory neurons, using recombinant adeno-associated viral (AAV) and lentiviral (LV) vectors. In the current study, AAV and LV vectors encoding the human frataxin cDNA were constructed and assessed for frataxin expression and function in primary FRDA patient fibroblast cell lines. FRDA fibroblasts have been shown to exhibit subtle biochemical changes, including increased mitochondrial iron and sensitivity to oxidant stress. Despite the inherent difficulty in working with primary cells, transduction of patient fibroblasts with either vector resulted in the expression of appropriately localized frataxin and partial reversal of phenotype.

OBJECTIVE To report the outcome of gene therapy in an infant with X-linked severe combined immunodeficiency (SCID-X1), which typically causes a lack of T and natural killer (NK) cells. DESIGN AND SETTING Ex-vivo culture and gene transfer procedures were performed at The Children's Hospital at Westmead, Sydney, NSW, in March 2002. Follow-up to March 2005 (36 months) is available. PATIENT A 9-month-old male infant with confirmed SCID-X1 (including complete absence of T cells) with an NK+ phenotype (a less common variant of SCID-X1), and no HLA-identical sibling donor available for conventional bone marrow transplantation. PROCEDURE CD34+ haemopoietic progenitor cells were isolated from harvested bone marrow and cultured with cytokines to stimulate cellular replication. Cells were then genetically modified by exposure to a retrovirus vector encoding human gamma c (the common gamma chain of several interleukin receptors; mutations affecting the gamma c gene cause SCID-X1). Gene-modified cells (equivalent to 1.3 x 10(6) CD34+/gamma c+ cells/kg) were returned to the infant via a central line. RESULTS T cells were observed in peripheral blood 75 days after treatment, and levels increased rapidly to 0.46 x 10(9) CD3+ cells/L at 5 months. Within 2 weeks of the appearance of T cells, there was a distinct clinical improvement, with early weight gain and clearance of rotavirus from the gut. However, T-cell levels did not reach the reference range, and immune reconstitution remained incomplete. The infant failed to thrive and developed weakness, hypertonia and hyperreflexia in the legs, possibly the result of immune dysregulation. He went on to receive a bone marrow transplant from a matched unrelated donor 26 months after gene therapy. CONCLUSIONS This is the first occasion that gene therapy has been used to treat a genetic disease in Australia. Only partial immunological reconstitution was achieved, most likely because of the relatively low dose of gene-corrected CD34+ cells re-infused, although viral infection during the early phase of T-cell reconstitution and the infant's NK+ phenotype may also have exerted an effect.

The boundary-edges code for a benzenoid H is defined as the lexicographically maximum code obtained traveling around the boundary of H and noting the number of edges of each successive hexagon traveled. This code is extended to the class of all planar polyhexes by allowing in cases of multiple-connectedness to travel from the boundary to each hole and around this hole. Its length is compared with that of other codes for benzenoids. It is then shown how the boundary-edges code can be used to easily find if a polyhex H is simply connected, cata-condensed, branched, has an equal number of peaks and valleys or has some symmetry.

Let N = (V, E) be an undirected network with n vertices and m edges (i.e., ¦V¦ = n and ¦E¦ = m ) in which each edge has a positive length. We study the length of the shortest path trees of N rooted at x (the length of a shortest path tree is defined to be the sum of the lengths of its edges) and the sum of distances from x to all (other) vertices of N, where x may be a vertex or an internal point of an edge. We first present an O(mn log n) algorithm to find a shortest shortest path tree, i.e., a shortest path tree with minimum length, and then give an algorithm with the same complexity to determine a maximum set of non-equivalent efficient points of N for the two criteria cited above. Finally, we extend these results to networks with some non-positive edge lengths as well as to directed networks.

The Edmonds Matching Algorithm, which leads easily to finding a perfect matching in a chemical graph, which is equivalent to a Kekule structure in a conjugated molecule, is recalled. An extension is made to the case where only vertices of a specified set must be covered by edges of the matching which is sought.

A benzenoid systemH is a finite connected subgraph of the infinite hexagonal lattice with out cut bonds and non-hexagonal interior faces. The branching graphG ofH consists of all vertices ofH of degree 3 and bonds among them. In this paper, the following results are obtained: (1) A necessary condition for a benzenoid system to have a Hamiltonian circuit. (2) A necessary and sufficient condition for a benzenoid system to have a Hamiltonian path. (3) A characterization of connected subgraphs of the infinite hexagonal lattice which are branching graphs of benzenoid systems. (4) A proof that if a disconnected subgraph G of the infinite hexagonal lattice given along with the positions of its vertices is the branching graph of a benzenoid system H, then H is unique.

It is shown that the Clar number of a benzenoid hydrocarbon H (defined as the number of circles in a Clar formula, or equivalently as the maximum number of mutually resonant hexagons of H) can be determined by mixed-integer programming. Moreover, linear programming appears to suffice in practice to find in moderate computing time the Clar number of pericondensed hydrocarbons with more than a thousand hexagons.

Let H denote a simply-connected cata-condensed polyhex. It is shown that if H has three hexagons in a row it does not have a maximum number of Kekulé structures. Otherwise, its number of Kekulé structures is equal to its number of sets of disjoint hexagons (including the empty set). These results lead to an efficient algorithm to determine simply-connected cata-condensed polyhexes with a maximum number of Kekulé structures. A table of such values of H with up to 100 hexagons is provided.

Consider a benzenoid system with fixed bonds and the subgraph obtained by deleting fixed double bonds together with their end vertices and fixed single bonds without their end vertices. It has often been observed for particular benzenoid systems, and conjectured (or stated) that, in general, such a subgraph has at least two components, and that each component is also a benzenoid system and is normal. But there are no rigorous proofs for that. The aim of this paper is to present mathematical proofs of those two facts. It is also shown that if a benzenoid system has a single hexagon as one of its normal components then it has at least three normal components.

A method for computing various upper bounds for the Clar number (defined as the number of circles in a Clar formula) of a benzenoid hydrocarbon is given. Based on this method two particular upper bounds are presented. For various examples, one of these bounds is sharp. Heuristic use of the method to find the Clar number of a given benzenoid hydrocarbon is also illustrated.

The development of leukemia as a consequence of vector-mediated genotoxicity in gene therapy trials for X-linked severe combined immunodeficiency (SCID-X1) has prompted substantial research effort into the design and safety testing of integrating vectors. An important element of vector design is the selection and evaluation of promoter-enhancer elements with sufficient strength to drive reliable immune reconstitution, but minimal propensity for enhancer-mediated insertional mutagenesis. In this study, we set out to explore the effect of promoter-enhancer selection on the efficacy and safety of human immunodeficiency virus-1-derived lentiviral vectors in γc-deficient mice. We observed incomplete or absent T- and B-cell development in mice transplanted with progenitors expressing γc from the phosphoglycerate kinase (PGK) and Wiscott–Aldrich syndrome (WAS) promoters, respectively. In contrast, functional T- and B-cell compartments were restored in mice receiving an equivalent vector containing the elongation factor-1-α (EF1α) promoter; however, 4 of 14 mice reconstituted with this vector subsequently developed lymphoma. Extensive analyses failed to implicate insertional mutagenesis or γc overexpression as the underlying mechanism. These findings highlight the need for detailed mechanistic analysis of tumor readouts in preclinical animal models assessing vector safety, and suggest the existence of other ill-defined risk factors for oncogenesis, including replicative stress, in gene therapy protocols targeting the hematopoietic compartment.

A systematic method of constructing all 3-resonant benzenoid systems (in which any i disjoint hexagons (i = 1, 2, 3) are mutually resonant) is presented. Based on this method, an efficient procedure (from the computing point of view) of drawing a Clar formula for a 3-resonant benzenoid system is given. In addition, it is shown that the number of circles in a Clar formula of a 3-resonant benzenoid system with n vertices is greater than or equal to n/8.

A hexagonal system is a connected plane graph without cut vertices in which each interior face is a regular hexagon. A linear algorithm is proposed to find all fixed bonds in a hexagonal system which has a Kekule structure, i.e. all edges belonging to all or none of the perfect matchings of that hexagonal system.

Mutant proteins have the potential to exert dominant-negative effects that might limit the therapeutic efficacy of their wild-type counterparts after gene transfer. For ornithine transcarbamylase (OTC) deficiency, in vitro studies have suggested the presence of dominant-negative effects, however, supporting in vivo studies have not been conducted. In this study, we exploited the capacity of recombinant adeno-associated virus (rAAV) 2/8 vectors to deliver transgenes to the mouse liver with high efficiency to determine whether expression of selected OTC mutant proteins exert inhibitory effects on endogenous wild-type OTC enzymatic activity. Using site-directed mutagenesis we constructed three OTC mutants with a theoretical or reported in vitro capacity to exert dominant-negative effects, and delivered these to the liver using rAAV2/8. Each mutation had been earlier identified in patients with OTC deficiency. Treated mice showed no increase in urinary orotic acid levels or reduction in OTC activity despite supra-physiological expression of the mutant proteins, consistent with an absence of dominant-negative effects. These data have important implications for the development of gene therapy strategies for OTC deficiency and validate a model system in which potential dominant-negative effects of specific mutations in prospective patients can be examined empirically before gene therapy.

The aim of this study was to evaluate the ability of local overexpression of indoleamine dioxygenase (IDO) to abrogate rat liver transplant rejection by the use of an adeno-associated virus vector [recombinant adeno-associated virus 2/8 (rAAV2/8)] to deliver the transgene to the allograft prior to transplantation. A green fluorescent protein (GFP)-expressing vector [recombinant adeno-associated virus 2/8-liver-specific promoter 1-enhanced green fluorescent protein (rAAV2/8-LSP1-eGFP)] was used to examine the kinetics of expression and optimal dosing for transduction of Piebald Virol Glaxo (PVG) rat livers. A vector encoding the rat IDO gene (rAAV2/8-LSP1-rIDO) was constructed and tested by its ability to induce tryptophan catabolism and kynurenine production in vitro and in vivo. PVG donor rats were injected, via the portal vein, with rAAV2/8-LSP1-rIDO 2 weeks before transplantation into PVG strain isograft or Lewis (LEW) strain allograft recipients. With the enhanced GFP vector, 29.5% and 47.4% of hepatocytes were found to express GFP at 3 and 6 weeks after injection, respectively. In untransplanted PVG animals, the rAAV2/8-LSP1-rIDO vector induced, 3 weeks after administration, a 1.8-fold increase (P = 0.0161) in liver IDO activity, which was associated with a fall in serum tryptophan to 0.5 times the baseline level (P < 0.001). PVG recipients of PVG liver isografts pretreated with the IDO-expressing vector had a 45% lower level of serum tryptophan than recipients of isografts pretreated with the GFP-expressing vector (P = 0.03). LEW recipients of PVG liver allografts pretreated with the rat IDO vector had a median survival time of 12 days, whereas recipients of allografts pretreated with rAAV2/8-LSP1-eGFP had a median survival time of 13 days (P = 0.38). Both groups displayed similar histological features of acute cellular rejection. In conclusion, rAAV2/8 vectors produce highly efficient, though delayed, hepatocyte transduction in vivo and provide a useful gene delivery tool for transplantation models. However, gene delivery using IDO was unsuccessful in prolonging rat liver allograft survival.

It is proved that for any hexagonal system there is a peak and a valley which are border adjacent (the path from the peak to the valley along the border is monotone) and such that either the wetting border of the peak contains no peaks or the catching border of the valley contains no valleys. Based on this property, a revised peeling algorithm is given to find a perfect matching for a hexagonal system if it exists. As a consequence, it is shown that the matching between peaks and valleys induced by perfect path systems is unique.

For a given positive integer k , a benzenoid system is k -resonant if all of its i (1,2, ·, k ) disjoint hexagons are mutually resonant. We give several criteria (from topological aspect) to determine whether or not a given benzenoid system is k -resonant ( i ⩾2), and show that a benzenoid system is k -resonant ( k ⩾3) if, and only if, it is 3-resonant.

On propose un algorithme en O (mn log n) pour determiner un point d'un reseau avec m arcs et n sommets qui minimise la variance des distances ponderees a tous les sommets

This study initially sought to investigate the immunostimulatory properties of recombinant adeno-associated virus (rAAV) with a view to developing a genetic vaccine for malaria using muscle as a target tissue. To augment humoral immunity, the AAV-encoded antigen was genetically fused with CTLA4-Ig, a recombinant molecule that binds B7 costimulatory molecules. At 10(9) vg, CTLA4-Ig fusion promoted the humoral immune response 100-fold and was dependent on CTLA4-Ig binding with B7 costimulatory molecules, confirming plasmid DNA models using this strategy. In distinct contrast, 10(12)-10(13) vg of rAAV1 specifically induced long-lived humoral tolerance through a mechanism that is independent of CTLA4-Ig binding with B7. This finding was unexpected, as rAAV delivery to muscle, unlike liver, has shown that this tissue provides a highly immunogenic environment for induction of humoral immunity against rAAV transgene products. An additional unpredicted consequence of antigen fusion with CTLA4-Ig was the enhancement of antigen expression by approximately one log, an effect mapped to the hinge and Fc domain of IgG(1,) but not involving antigen dimerization or the neonatal Fc receptor. Collectively, these findings significantly advance the potential of rAAV both as a vaccine or immunotherapeutic platform for the induction of antigen-specific humoral immunity or tolerance and as a gene therapeutic delivery system.

Let t(G) denote cardinality of a maximum induced forest of a graph G with n vertices. For connected simple cubic graphs G without triangles, it is shown that t(G)⩾2n3 except for two particular graphs. This lower bound is sharp and it improves a result due to J.A. Bondy, et al. [1]. Using this result, we show that Ewald Speckenmeyer's Conjecture, i.e. t(G)⩾2n3 for all biconnected cubic graphs G with girth 4, is true, except for two particular graphs, which we describe.

Background Development of effective and durable gene therapy for treatment of the respiratory manifestations of cystic fibrosis remains a formidable challenge. Obstacles include difficulty in achieving efficient gene transfer to mature airway epithelium and the need to stably transduce self-renewing epithelial progenitor cells in order to avoid loss of transgene expression through epithelial turnover. Targeting the developing airway epithelium during fetal life offers the prospect of circumventing these challenges. Methods In the current study we investigated vesicular stomatitis virus glycoprotein (VSVg)-pseudotyped HIV-1-derived lentivirus vector-mediated gene transfer to the airway epithelium of mid-gestation fetal lambs, both in vitro and in vivo. In the in vitro studies epithelial sheet explants and lung organ culture were used to examine transduction of the proximal and more distal airway epithelium, respectively. For the in vivo studies, vector was delivered directly into the proximal airway. Results We found that even during the early pseudoglandular and canalicular phases of lung development, occurring through mid-gestation, the proximal bronchial airway epithelium was relatively mature and highly resistant to lentivirus-mediated transduction. In contrast, the more distal bronchiolar airway epithelium was relatively permissive for transduction although the absolute levels achieved remained low. Conclusion This result is promising as the bronchiolar airway epithelium is a major site of pathology in the cystic fibrosis airway, and much higher levels of transduction are likely to be achieved by developing strategies that increase the amount of vector reaching the more distal airway after intratracheal delivery. Copyright © 2007 John Wiley & Sons, Ltd.

This study explores the utility of recombinant adeno-associated virus (rAAV) as a genetic vaccine delivery system using muscle as a target tissue. A single injection of rAAV encoding the malarial antigens MSP4 (Plasmodium falciparum) or MSP4/5 (Plasmodium yoelii) stimulated long-term antigen-specific antibody responses. Anti-MSP4/5 immunity stimulated by AAV was not protective against P. yoelii infection and efforts taken to augment antibody responses against MSP4/5, either by priming with plasmid DNA or AAV and boosting with rAAV were unsuccessful. Alternative strategies such as inclusion of genetic adjuvants into the AAV vector will be necessary to stimulate an adequate level of anti-malarial protective immunity in this model.

8 mm spin magnetic filter covering 26.5 to 40 GHz frequency ranges have been designed. This filter has an insertion loss of 10 dB, the bandwidth of 120-200 MHz, the off-resonance isolation of 40 dB, and a maximum tuning current of 1.2 A at 40 GHz. The magnetic circuit is made of compound material. The tapered pole pieces consists of Fe-Co-V alloy. The magnetic shell consists of a soft magnetic high-permeability nickel-iron alloy. In order to improve the magnetic design the tapered pole tips be used.

In this paper ferrite-tuned filter designs are described. The YIG sphere and design parameters are described also. This filter covered the frequency range 250 to 800 MHz. The insertion loss was 8 dB with off-resonance isolation of 75 dB. The /spl Delta/f/sub 3dB/ is greater than 5 MHz. The temperature operating range is -40 to +70/spl deg/C.

Background: Cystic fibrosis is the most common life-shortening genetic disease in the Caucasian population, affecting |[sim]|1 in 2,500 births. Inheritance is AR and results from mutations in the CFTR, which functions in transepithelial salt and water regulation. In humans, lung damage is the primary source of morbidity, although exocrine pancreatic dysfunction is generally present. Difficulties in gene delivery to the mature airway epithelium and early onset airway damage provide a rationale for exploring gene therapy during lung development. In this study, we evaluated lentivirus-mediated gene transfer to cultured fetal sheep airway epithelium and lung tissue explants. Model choice was based on fetal size, a pattern of airway development that parallels the human lung, the relatively late appearance of immuno-competence and tolerance of the ovine uterus to fetal manipulation.