Clinical and experimental studies of intraperitoneal lipolysis and the development of clinically relevant pancreatic fistula after pancreatic surgery.

BACKGROUND: Visceral obesity is one of the risk factors for clinically relevant pancreatic fistula after pancreatic resection. The objective of this study was to evaluate the impact of intraperitoneal lipolysis on postoperative pancreatic fistula. METHODS: The degree of intraperitoneal lipolysis was investigated by measuring the free fatty acid concentration in drain discharge in patients after pancreatic resection. An experimental pancreatic fistula model was prepared by pancreatic transection, and the impact of intraperitoneal lipolysis was evaluated by intraperitoneal administration of triolein (triglyceride) with, or without orlistat (lipase inhibitor). RESULTS: Thirty-three patients were included in the analysis. The free fatty acid concentration in drain discharge on postoperative day 1 was significantly associated with the development of a clinically relevant pancreatic fistula (P = 0·004). A higher free fatty acid concentration in drain discharge was associated with more visceral adipose tissue (P = 0·009). In the experimental model that included 98 rats, intraperitoneal lipolysis caused an increased amount of pancreatic juice leakage and multiple organ dysfunction. Intraperitoneal administration of a lipase inhibitor reduced lipolysis and prevented deterioration of the fistula. CONCLUSION: Intraperitoneal lipolysis significantly exacerbates pancreatic fistula after pancreatic resection. Inhibition of lipolysis by intraperitoneal administration of a lipase inhibitor could be a promising therapy to reduce clinically relevant postoperative pancreatic fistula. Surgical relevance Clinically, there are two types of pancreatic fistula after pancreatic resections: harmless biochemical leak and harmful clinically relevant pancreatic fistula. Visceral obesity is one of the known risk factors for clinically relevant pancreatic fistula; however, the underlying mechanisms remained to be elucidated. Patients with clinically relevant pancreatic fistula had a higher free fatty acid concentration in the drain discharge, suggesting a relationship between intraperitoneal lipolysis and pancreatic fistula. The experimental model of pancreatic fistula demonstrated that intraperitoneal lipolysis caused deterioration in pancreatic fistula, suggesting that intraperitoneal lipolysis is one of the mechanisms that drives biochemical leakage to clinically relevant pancreatic fistula. Intraperitoneal administration of a lipase inhibitor prevented lipolysis as well as pancreatic fistula deterioration in the experimental model, suggesting a future clinical application for lipase inhibitors in prevention of clinically relevant pancreatic fistula.

Long-term investigation of phosphorus removal by iron electrocoagulation in small-scale wastewater treatment plants.

Small-scale wastewater treatment plants (SWTPs), called Johkasou, are widely used as decentralized and individual wastewater treatment systems in sparsely populated areas in Japan. Even in SWTPs, nutrients should be removed to control eutrophication. An iron electrolysis method is effective to remove phosphorus chemically in SWTPs. However, it is necessary to determine the precise conditions under which phosphorus can be effectively and stably removed in full scale SWTPs for a long period. Therefore, long-term phosphorus removal from SWTPs was investigated and optimum operational conditions for phosphorus removal by iron electrolysis were analyzed in this study. Efficient phosphorus removal can be achieved for a long time by adjusting the amount of iron against the actual population equivalent. The change of the recirculation ratio had no negative effect on overall phosphorus removal. Phosphorus release to the bulk phase was prevented by the accumulated iron, which was supplied by iron electrolysis, resulting in stable phosphorus removal. The effect of environmental load reduction due to phosphorus removal by iron electrolysis was greater than the cost of power consumption for iron electrolysis.

Biodegradable gelatin/beta-tricalcium phosphate sponges incorporating recombinant human fibroblast growth factor-2 for treatment of recession-type defects: A split-mouth study in dogs.

BACKGROUND AND OBJECTIVE: Tissue engineering by using recombinant human (rh) growth factor technology may offer a promising therapeutic approach for treatment of gingival recession. Fibroblast growth factor-2 (FGF-2) has shown the ability to promote periodontal regeneration. Gelatin/beta-tricalcium phosphate (gelatin/ß-TCP) sponges have been developed to control the release of growth factors. The present study evaluated the periodontal regenerative efficacy of rhFGF-2 by comparing gelatin/ß-TCP sponges incorporated with rhFGF-2 to the scaffolds alone in artificially created recession-type defects in dogs. MATERIAL AND METHODS: Critically sized buccal gingival recession defects were surgically created on maxillary canine teeth of five dogs. In each animal, defects were randomized to receive either a gelatin/ß-TCP sponge soaked with rhFGF-2 (gelatin/ß-TCP/rhFGF-2) or phosphate-buffered saline (gelatin/ß-TCP). Eight weeks after surgery, biopsy specimens were obtained and subjected to microcomputed tomography and histological analyses. RESULTS: Complete root coverage was achieved in both groups. Microcomputed tomography revealed significantly greater new bone volume in the gelatin/ß-TCP/rhFGF-2 group. Histologically, both groups achieved periodontal regeneration; however, gelatin/ß-TCP/rhFGF-2 sites exhibited more tissue regeneration, characterized by significantly larger amounts of new cementum and new bone. Gelatin/ß-TCP sites featured increased long junctional epithelium and connective tissue attachment. In the gelatin/ß-TCP/rhFGF-2 sites, new bone exhibited many haversian canals and circumferential lamellae as well as remarkably thick periosteum with blood vascularization and hypercellularity. CONCLUSION: Within the limitations of this study, rhFGF-2 in gelatin/ß-TCP sponges exhibits an increased potential to support periodontal wound healing/regeneration in canine recession-type defects.

Improvement of phosphorus removal by calcium addition in the iron electrocoagulation process.

Small-scale wastewater treatment plants (SWTPs) are widely used as decentralized wastewater treatment systems in sparsely populated areas of Japan. Iron electrolysis, an electrocoagulation technology, is installed in these SWTPs for phosphorus removal. Phosphorus can be removed via the formation of an insoluble compound containing phosphate and iron, such as FePO4; however, it was necessary to determine the conditions under which phosphorus can be effectively and stably removed in actual SWTPs. According to previous studies using iron compounds, improved phosphorus removal was obtained by Ca addition. It is therefore thought that calcium addition may also be effective in improving the phosphorus removal during iron electrolysis in SWTPs. It is also important to determine the chemical state of iron to understand the phosphorus removal mechanism during iron electrolysis. In this study, laboratory-scale batch experiments with the iron electrolysis method were conducted to investigate the effect of phosphorus removal using treated wastewater from actual SWTPs without or with Ca addition. The results indicated that the addition of Ca improved the phosphorus removal performance. Furthermore, phosphorus removal was inhibited in the presence of high dissolved organic carbon (DOC). The X-ray absorption fine structure measurements of the produced particulates in the experiments showed no substantial change in the chemical state of iron without or with Ca addition. The statistical analyses revealed the range of improving or inhibiting effects on phosphorus removal due to the Ca and DOC. Thus, the results of this study provided useful information pertaining to the influence of coexisting substances on phosphorus removal and the chemical state of iron in the produced particulates.

Ridge augmentation using recombinant human fibroblast growth factor-2 with biodegradable gelatin sponges incorporating ß-tricalcium phosphate: a preclinical study in dogs.

BACKGROUND AND OBJECTIVE: Fibroblast growth factor-2 (FGF-2) regulates the proliferation and differentiation of osteogenic cells, resulting in the promotion of bone formation. Biodegradable gelatin sponges incorporating ß-tricalcium phosphate (ß-TCP) have been reported as a scaffold, which has the ability to control growth factor release, offering sufficient mechanical strength and efficient migration of mesenchymal cells. In this study, we evaluated the effects of the combined use of recombinant human FGF-2 (rhFGF-2) and gelatin/ß-TCP sponge on ridge augmentation in dogs. MATERIAL AND METHODS: Six male beagle dogs were used in this study. Twelve wk after tooth extraction, bilateral 10 × 5 mm (width × depth) saddle-type defects were created 3 mm apart from the mesial side of the maxillary canine. At the experimental sites, the defects were filled with gelatin/ß-TCP sponge infiltrated with 0.3% rhFGF-2, whereas gelatin/ß-TCP sponge infiltrated with saline was applied to the control sites. Eight wk after surgery, qualitative and quantitative analyses were performed. RESULTS: There were no signs of clinical inflammation at 8 wk after surgery. Histometric measurements revealed that new bone height at the experimental sites (2.98 ± 0.65 mm) was significantly greater than that at the control sites (1.56 ± 0.66 mm; p = 0.004). The total tissue height was greater at the experimental sites (6.62 ± 0.66 mm) than that at the control sites (5.95 ± 0.74 mm), although there was no statistical significant difference (p = 0.051). Cast model measurements revealed that the residual defect height at the experimental sites (2.31 ± 0.50 mm) was significantly smaller than that at the control sites (3.51 ± 0.78 mm; p = 0.012). CONCLUSION: The combined use of rhFGF-2 and gelatin/ß-TCP sponge promotes ridge augmentation in canine saddle-type bone defects.

Osteochondral defect repair using bilayered hydrogels encapsulating both chondrogenically and osteogenically pre-differentiated mesenchymal stem cells in a rabbit model.

OBJECTIVE: To investigate the ability of cell-laden bilayered hydrogels encapsulating chondrogenically and osteogenically (OS) pre-differentiated mesenchymal stem cells (MSCs) to effect osteochondral defect repair in a rabbit model. By varying the period of chondrogenic pre-differentiation from 7 (CG7) to 14 days (CG14), the effect of chondrogenic differentiation stage on osteochondral tissue repair was also investigated. METHODS: Rabbit MSCs were subjected to either chondrogenic or osteogenic pre-differentiation, encapsulated within respective chondral/subchondral layers of a bilayered hydrogel construct, and then implanted into femoral condyle osteochondral defects. Rabbits were randomized into one of four groups (MSC/MSC, MSC/OS, CG7/OS, and CG14/OS; chondral/subchondral) and received two similar constructs bilaterally. Defects were evaluated after 12 weeks. RESULTS: All groups exhibited similar overall neo-tissue filling. The delivery of OS cells when compared to undifferentiated MSCs in the subchondral construct layer resulted in improvements in neo-cartilage thickness and regularity. However, the addition of CG cells in the chondral layer, with OS cells in the subchondral layer, did not augment tissue repair as influenced by the latter when compared to the control. Instead, CG7/OS implants resulted in more irregular neo-tissue surfaces when compared to MSC/OS implants. Notably, the delivery of CG7 cells, when compared to CG14 cells, with OS cells stimulated morphologically superior cartilage repair. However, neither osteogenic nor chondrogenic pre-differentiation affected detectable changes in subchondral tissue repair. CONCLUSIONS: Cartilage regeneration in osteochondral defects can be enhanced by MSCs that are chondrogenically and osteogenically pre-differentiated prior to implantation. Longer chondrogenic pre-differentiation periods, however, lead to diminished cartilage repair.

Advances in tooth agenesis and tooth regeneration.

The lack of treatment options for congenital (0.1%) and partial (10%) tooth anomalies highlights the need to develop innovative strategies. Over two decades of dedicated research have led to breakthroughs in the treatment of congenital and acquired tooth loss. We revealed that by inactivating USAG-1, congenital tooth agenesis can be successfully ameliorated during early tooth development and that the inactivation promotes late-stage tooth morphogenesis in double knockout mice. Furthermore, Anti- USAG-1 antibody treatment in mice is effective in tooth regeneration and can be a breakthrough in treating tooth anomalies in humans. With approximately 0.1% of the population suffering from congenital tooth agenesis and 10% of children worldwide suffering from partial tooth loss, early diagnosis will improve outcomes and the quality of life of patients. Understanding the role of pathogenic USAG-1 variants, their interacting gene partners, and their protein functions will help develop critical biomarkers. Advances in next-generation sequencing, mass spectrometry, and imaging technologies will assist in developing companion and predictive biomarkers to help identify patients who will benefit from tooth regeneration.

Hepatocyte growth factor stimulates root growth during the development of mouse molar teeth.

BACKGROUND AND OBJECTIVE: It is well known that tooth root formation is initiated by the development of Hertwig's epithelial root sheath (HERS). However, relatively little is known about the regulatory mechanisms involved in root development. As hepatocyte growth factor (HGF) is one of the mediators of epithelial-mesenchymal interactions in rodent tooth, the objective of this study was to examine the effects of HGF on the root development of mouse molars. MATERIAL AND METHODS: The HERS of mouse molars and HERS01a, a cell line originated from HERS, were used in this study. For detection of HGF receptors in vivo and in vitro, we used immunochemical procedures. Root development was assessed by implanting molar tooth germs along with HGF-soaked beads into kidney capsules, by counting cell numbers in HERS01a cell cultures and by performing a 5'-bromo-2'-deoxyuridine (BrdU) assay in an organ-culture system. RESULTS: HGF receptors were expressed in the enamel epithelium of molar germs as well as in HERS cells. HGF stimulated root development in the transplanted tooth germs, the proliferation of HERS01a cells in culture and HERS elongation in the organ-culture system. Examination using BrdU revealed that cell proliferation in HERS was increased by treatment with HGF, especially that in the outer layer of HERS. This effect was down-regulated when antibody against HGF receptor was present in the culture medium. CONCLUSION: Our results raise the possibility that HGF signaling controls root formation via the development of HERS. This study is the first to show that HGF is one of the stimulators of root development.

Anti-USAG-1 therapy for tooth regeneration through enhanced BMP signaling.

Uterine sensitization-associated gene-1 (USAG-1) deficiency leads to enhanced bone morphogenetic protein (BMP) signaling, leading to supernumerary teeth formation. Furthermore, antibodies interfering with binding of USAG-1 to BMP, but not lipoprotein receptor-related protein 5/6 (LRP5/6), accelerate tooth development. Since USAG-1 inhibits Wnt and BMP signals, the essential factors for tooth development, via direct binding to BMP and Wnt coreceptor LRP5/6, we hypothesized that USAG-1 plays key regulatory roles in suppressing tooth development. However, the involvement of USAG-1 in various types of congenital tooth agenesis remains unknown. Here, we show that blocking USAG-1 function through USAG-1 knockout or anti-USAG-1 antibody administration relieves congenital tooth agenesis caused by various genetic abnormalities in mice. Our results demonstrate that USAG-1 controls the number of teeth by inhibiting development of potential tooth germs in wild-type or mutant mice missing teeth. Anti-USAG-1 antibody administration is, therefore, a promising approach for tooth regeneration therapy.

In situ real-time monitoring of changes in the surface roughness during nonadiabatic optical near-field etching.

We performed in situ real-time monitoring of the change in surface roughness during self-organized optical near-field etching. During near-field etching of a silica substrate, we detected the scattered light intensity from a continuum wave (CW) laser (lambda = 633 nm) in addition to the etching CW laser (lambda = 532 nm) light source. We discovered that near-field etching not only decreases surface roughness, but also increases the number of scatterers, as was confirmed by analyzing the AFM image. These approaches provide optimization criteria for the etching parameter and hence for further decreases in surface roughness.

Coexistence of the Kondo effect and spin glass physics in Fe-doped NbS2.

We report the coexistence of the Kondo effect and spin glass behavior in Fe-doped NbS2 single crystals. The Fe x NbS2 shows the resistance minimum and negative magnetoresistance due to the Kondo effect, and exhibits no superconducting behavior at low temperatures. The resistance curve follows a numerical renormalization-group theory using the Kondo temperature [Formula: see text] K for x = 0.01 as evidence of Kondo effect. Scanning tunneling microscope/spectroscopy (STM/STS) revealed the presence of Fe atoms near sulfur atoms and asymmetric spectra. The magnetic susceptibility exhibits a feature of spin glass. The static critical exponents determined by the universal scaling of the nonlinear part of the susceptibility suggest a three-dimensional Heisenberg spin glass. The doped-Fe atoms in the intra- and inter-layers revealed by the x-ray result can realize the coexistence of the Kondo effect and spin glass.

Retraction Note: Enhanced suppression of tumor growth using a combination of NK4 plasmid DNA-PEG engrafted cationized dextran complex and ultrasound irradiation.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Selective and sustained delivery of basic fibroblast growth factor (bFGF) for treatment of peripheral arterial disease: results of a phase I trial.

OBJECTIVES: The aim of this study was to evaluate the safety of selective and sustained delivery of basic fibroblast growth factor (bFGF) using acidic gelatine hydrogel microspheres (AGHMs) for the treatment of peripheral arterial disease (PAD). MATERIALS AND METHODS: We conducted a non-randomised and uncontrolled trial involving prospective observation of eight patients (eight limbs) with PAD - five limbs with arteriosclerosis obliterans and three limbs with thromboangiitis obliterans, five limbs (three arms and two legs) with critical limb ischaemia (CLI) and three limbs with intermittent claudication (IC) - who were followed up for 6 months or more. AGHM suspension containing 100 microg bFGF was infused into the artery of the affected limb. Besides evaluation of safety and changes in symptoms, resting ankle-brachial pressure index measurement and transcutaneous PO(2) (tcPO(2)), angiography were conducted at baseline and then at various time points. Skin perfusion pressure as an index of CLI and claudication distance as an index of IC were also used to assess clinical improvement and limb perfusion. RESULTS: No serious adverse events were observed. All cases showed improvement in symptoms, although this was temporary in some patients. CONCLUSION: Selective delivery of bFGF using AGHMs was suggested to be safe and well-tolerated in patients with PAD.

Intraarticular administration of platelet-rich plasma with biodegradable gelatin hydrogel microspheres prevents osteoarthritis progression in the rabbit knee.

OBJECTIVE: To investigate the therapeutic potential of administration of gelatin hydrogel microspheres containing platelet-rich plasma (PRP), by examining its effects on progression of osteoarthritis (OA) in a rabbit model. METHODS: PRP and platelet-poor plasma (PPP) were prepared from rabbit blood. Adult rabbit chondrocytes were cultured in the alginate beads with the presence of 3% PRP or 3% PPP. Glycosaminoglycan (GAG) synthesis was quantified using dimethylmethylene blue assay. To confirm the anabolic effect of PRP in vivo, cartilage matrix gene expression was examined after intraarticular administration of PRP contained in gelatin hydrogel microspheres. The PRP contained in gelatin hydrogel microspheres was administered into the rabbit knee joint twice with an interval of 3 weeks, beginning 4 weeks after anterior cruciate ligament transection (ACLT). Ten weeks after ACLT, gross morphological and histological examinations were performed. RESULTS: PRP significantly stimulated chondrocyte GAG synthesis in vitro. In the knee joint, expression of proteoglycan core protein mRNA in the articular cartilage increased after administration of PRP contained in microspheres. Intraarticular injections of PRP in gelatin hydrogel microspheres significantly suppressed progression of OA in the ACLT rabbit model morphologically and histologically. CONCLUSION: The present findings indicate that sustained release of growth factors contained in PRP has preventive effects against OA progression. These preventive effects appear to be due to stimulation of cartilage matrix metabolism, caused by the growth factors contained in PRP.

Augmented anti-tumor therapy through natural targetability of macrophages genetically engineered by NK4 plasmid DNA.

The objective of this study is to genetically engineer macrophages (Mphi) for biological activation and evaluate their anti-tumor activity in a tumor-bearing mouse model. Mouse peritoneal Mphi were incubated on the surface of a culture dish which had been coated with the complex of a cationized dextran and luciferase plasmid DNA complex plus a cell adhesion protein, Pronectin for gene transfection (reverse transfection). When compared with the conventional transfection where Mphi were transfected in the medium containing the complex, the level of gene expression by the reverse method was significantly high and the time period of gene expression was prolonged. Confocal microscopic observation revealed that the plasmid DNA was localized in the cell nucleus to a higher extent by the reverse transfection method. Following the reverse transfection of Mphi by the plasmid DNA of a hepatocyte growth factor antagonist (NK4) complexed with the cationized dextran, the NK4 protein was secreted at a higher amount for a longer time period in contrast to the conventional transfection of free plasmid DNA. The NK4-transfected Mphi exhibited a stronger inhibition activity for in vitro growth of Meth-A fibrosarcoma cells. When injected intravenously into mice carrying a mass of Meth-A tumor cells, the Mphi engineered were accumulated in the tumor tissue and showed significant anti-tumor activity. It is concluded that the Mphi injected functioned as the natural carrier of tumor targeting for anti-tumor NK4 molecules, resulting in enhanced suppression of tumor growth at a high selectivity.

Mouse model of dermal fibrosis induced by one-time injection of bleomycin-poly(L-lactic acid) microspheres.

OBJECTIVE: Animal models are useful tools to study various aspects of human diseases. Bleomycin (BLM)-induced scleroderma mouse has been widely investigated as an animal model of scleroderma. Repeated injections of BLM, either daily or every other day, for 3-4 weeks are required to induce scleroderma in mice. Poly(L-lactic acid) (PLA) is a biodegradable, biocompatible and bioabsorbable device that has been widely investigated for controlled drug release. In this study, we fabricated BLM-containing PLA microspheres and subcutaneously injected them into C3H mice for only one time. METHODS: Treated skins were harvested at days 7 and 21. Then, histological examination and collagen content measurement assay were performed. The mRNA expression of alpha1(I) collagen (COL1A1), monocyte chemoattractant protein-1 (MCP-1), TGF-beta(1) and connective tissue growth factor (CTGF) were quantified by real-time PCR. RESULTS: Dermal fibrosis was histologically observed at day 7 after injection and remained present at day 21. Tissue responses against BLM-PLA microspheres alone were mild. Soluble collagen content and expression level of alpha1(I) collagen mRNA were significantly elevated at day 21. Expression levels of MCP-1 mRNA and TGF-beta(1) mRNA at day 7 and CTGF mRNA at day 21 were also elevated. CONCLUSION: The present study demonstrated for the first time that one-time injection of BLM-PLA microspheres can induce dermal fibrosis in C3H mice. BLM-PLA microspheres thus offer a labour-saving, simple and powerful tool to establish an animal model of BLM-induced dermal fibrosis.

Spermined dextran, a cationized polymer, as absorption enhancer for pulmonary application of peptide drugs.

Sperminated dextrans (SD) having different average molecular weights (MWs; 10, 40 and 70 kDa) and numbers of amino groups were prepared as cationized polymers for use as absorption enhancers. The absorption enhancing effects on the pulmonary absorption of insulin in rats and the permeation of FITC-dextran (MW 4,400, FD4) through calu-3 cell (human airway epithelial cell) monolayers by SD were evaluated. SD significantly enhanced the pulmonary absorption of insulin SD and the permeation of FD4 through calu-3 cells. The enhancing effects on the absorption insulin and permeation of FD4 through calu-3 cells increased with an increase in the molecular weigh of SD over the range 10-70 kDa. SD may interact directly with the luminal surface of mucus membranes via an ion-ion interaction and then induce signals that open tight junctions resulting in intercellular permeation of water soluble drugs. SD may be useful as an absorption enhancer for pulmonary delivery of peptide and protein drugs.

Blood permeability of a novel ceramic scaffold for bone morphogenetic protein-2.

A functionally graded apatite (fg-HAp) with body fluid permeability was developed from bovine bone. The tissue reaction of fg-HAp and its efficacy as a scaffold for recombinant human bone morphogenetic protein-2 (BMP-2) were evaluated histomorphometrically, and a component of permeable fluid into the fg-HAp was analyzed by immunoblotting assay. The fg-HAp block (27 mm(3)) combined with and without BMP-2 (5 microg) was implanted subcutaneously in 4-week-old Wistar rats. Histological examination showed that the surface and bulk degradations of the fg-HAp proceeded extensively and giant cells appeared on the fg-HAp at 2 weeks. Body fluid permeation was found inside the fg-HAp, and the fluid component was immunopositive for albumin. In addition, albumin was detected as a main component among proteins collected from the in vivo implanted fg-HAp. The bioabsorption of the fg-HAp was accelerated as BMP-2-induced bone matured. Histomorphometrical analysis at 4 weeks in the BMP-2/fg-HAp implant showed 59.0% in the total volume of bone and marrow. These results indicate that fg-HAp is an innovative, bioabsorbable bioceramic with fluid permeability characteristic, and may become a biointegrated scaffold for bone engineering.

Relationships among growth and different NOR phenotypes in a specific stock of rainbow trout (Oncorhynchus mykiss).

Growth is one of the most important aspects in the genetic improvement of cultured fish species. Consequently, genetic parameters related to this feature and their response to selection have been the focus of most research in this area. Such research indicates that, in general, there is enough additive genetic variance related to growth, justifying the use of selection. Based on the usefulness of cytogenetic and molecular markers in the fish culture, the aim of the present work was to analyze the possible relationships among cytogenetic characteristics, specifically the NOR phenotypes, and the increase in length and weight in specimens of the rainbow trout (Oncorhynchus mykiss), resultant from directed mating between homozygous females and heterozygous males according to their NOR phenotypic patterns. The equations of the relationship between length and weight of the analyzed specimens followed the model Wt = a Lt(b), showing b values higher than 3, determinant of a positive allometric growth. The results showed that the different NOR phenotypes were not related with the growth values for length and weight in any statistical test.

Enhanced suppression of tumor growth using a combination of NK4 plasmid DNA-PEG engrafted cationized dextran complex and ultrasound irradiation.

This investigation aims to determine experimentally whether or not ultrasound (US) irradiation is effective in enhancing the in vivo gene expression of NK4 plasmid DNA and suppressing tumor growth. NK4, composed of the NH2-terminal hairpin and subsequent four-kringle domains of hepatocyte growth factor (HGF), acts as an HGF-antagonist and angiogenesis inhibitor. Dextran was cationized by introducing spermine to the hydroxyl groups to allow for polyionic complexation with NK4 plasmid DNA. The cationized dextran was additionally modified with poly(ethylene glycol) (PEG) molecules giving PEG engrafted cationized dextran. Significant suppression of tumor growth was observed when PEG engrafted cationized dextran-NK4 plasmid DNA complexes were intravenously injected into mice carrying a subcutaneous Lewis lung carcinoma tumor mass with subsequent US irradiation when compared with the cationized dextran-NK4 plasmid DNA complex and naked NK4 plasmid DNA with or without US irradiation. We conclude that complexation with PEG-engrafted cationized dextran in combination with US irradiation is a promising way to target the NK4 plasmid DNA to the tumor for gene expression.