In this study, the mechanical properties of a self-made jet injector and a foreign product are tested from three aspects: penetration ability, injection completeness and injection dispersion. Correspondingly, three different experiments are designed and performed: dynamic pressure measurement, injection into silicon rubbers with fixed hardness yet different thickness and injection into polyacrylamide gels with fixed hardness. The results show similar mechanical properties between self-made system and the foreign system. The evaluation of the mechanical performance of jet injectors that consists of penetration ability, injection completeness and injection dispersion can describe the jet injection process effectively.
Hardness ; Injections, Jet ; instrumentation ; Materials Testing

A liquid jet injector employs compressed gas or spring to produce a high-velocity stream to deliver liquid drug into human body through skin. There are many clinical jet injection products available, none of which is domestic. A new liquid jet injector is designed based on a comprehensive analysis of the current products. The injector consists of an ejector, trigger and a re-positioning mechanism. The jets characteristics of sample injector are tested, and the results show that the maximum exit pressure is above 15 MPa, a threshold value for penetrating into the skin.
Equipment Design ; Humans ; Injections, Intradermal ; instrumentation ; methods ; Injections, Jet ; instrumentation ; methods

Powder needleless injection (PNI) is a novel method for administration of drugs, especially proteins and peptides. In this study, fluoresceinsodium was selected as model drug to evaluate and optimize the bioavailability of PNI on rabbits. The determination method was HPLC-FLD. The analyzing time of the method was within 3 minutes. A linear relationship of fluoresceinsodium was good between 0.0047 and 0.1872 microg x mL(-1) and the recovery of the method was larger than 97.6% (RSD < 3.6%). With the orthogonal experiments, the influence on PNI of several factors was compared. The model of the injector was the most important factor to enhance the bioavailability while gas pressure and drug diameter had positive correlation with both bioavailability and damage on skin. A condition of PNI, injector model C3, gas pressure of 4 MPa and drug diameter of 90-125 microm, was carried out and the bioavailability of self-designed PNI system was 34.9% in compare of the result (33%) of foreign correspording product in some degree. However, the mainly applicable drug types of PNI are proteins and peptides which is of high cost. So the self-designed PNI system needs to be improved.
Animals ; Area Under Curve ; Biological Availability ; Fluorescein ; administration & dosage ; analysis ; pharmacokinetics ; Injections, Jet ; methods ; Particle Size ; Powders ; Rabbits

In this study, a self-designed powder needleless injection system was compared with subcutaneous injection using a needle and syringe to deliver tetanus toxoid (TT) into mice to elicit immunity. First of all, factors influencing the prepartion of TT into powder by being absorbed on aluminium hydroxide were investigated and the micromeritic characters of Al (OH)3-TT powder were observed with optical microscope and laser particle analyzer. The results showed that salt concentration and absorption time had an enhancive effect on drug loading, but the pH value and temperature did not influence the absorption reaction obviously. The absorption reaction was optimized with sodium chloride concentration of 0.4 mol x L(-1) and lasting for 10 min. The average diameter of Al(OH)3-TT powder prepared with conditions optimized above was (60.6 +/- 4.4) microm. The immunization effect of TT was determined through enzyme-linked immunosorbent assay (ELISA) of the concentration of IgG antibody elicited by TT. With delivery of Al(OH)3-TT (of 30 microg TT) by powder needleless injection to mice, the IgG antibody concentration were (6.19 +/- 0.52) and (10.70 +/- 0.78) U x L(-1) after immunization of 4 and 8 weeks, respectively, while the values were (4.25 +/- 0.58) and (7.48 +/- 0.57) U x L(-1) by subcutaneous injection (of 20 microg TT) using a needle and syringe. The results suggested that the self-designed powder needleless injection of Al(OH)3-TT was comparable to subcutaneous injection with a good immunity.
Adjuvants, Immunologic ; administration & dosage ; Aluminum Hydroxide ; administration & dosage ; Animals ; Drug Compounding ; Female ; Immunoglobulin G ; blood ; Injections, Jet ; Male ; Mice ; Particle Size ; Powders ; Tetanus Toxoid ; administration & dosage ; immunology

BACKGROUNDRev is necessary for exporting unspliced and incompletely spliced intron containing HIV mRNAs and for HIV replication. The aim of this study is to develop a kind of selective suicide construct that can specifically and directly induce HIV infected cells into apoptosis based on the high affinity of Rev and Rev response element (RRE).

METHODSMolecular-cloning technique was used to synthesis Rev dependent TNF-R1 expression construct pDM128-TNF-R1 (pT128) that contains RRE and TNFR1 gene. Restriction digestion, Polymerase Chain Reaction (PCR) and DNA sequencing were processed and the exactness and correctness of the inserted TNF-R1 gene in pT128 were confirmed repeatedly. The expression of pT128 co-transfected with different combination of other plasmids by calcium phosphate-DNA co-precipitation in Helas and by gene gun transfection in keratinocytes was further tested by flow-cytometry and cell counted under microscope.

RESULTSThe new plasmid specifically expressed TNF-R1 in Helas when co-transfected with pRev but did not when without pRev. Indirect expression of TNF-R1 from pT128 was slower than the direct expression of that from Hu p60 TNFR1 in pDC302 (pT60), but all those pT60 or pT128 transfected cells showed apoptosis at last while TNF-R1 was sufficiently expressed. Other kinds of Rev expression construct such as pAD8 and a chimeric HIV vaccine also can switched on the selective expression of pT128. Not only Rev-dependent expression in Helas, pT128 also normally expressed its TNF-R1 in keratinocytes. Co-transfected with pRev or pAD8 that expressed Rev, pT128 expressed TNF-R1 and induced apoptosis of green fluorescent keratinocytes in skin explant. The number of green fluorescent keratinocytes co-transfected by pT128 plus pRev or pAD8 was gradually outnumbered by that co-transfected by pT128 only. The difference was more significant after culturing for 72 hours.

CONCLUSIONSRev dependent pT128 is able to selectively induce apoptosis of HIV-infected or Rev-expressed target cells by expression of TNF-R1. The new strategy based on manipulation of the regulatory protein of HIV may be valuable in design of new HIV vaccine.

AIDS Vaccines ; immunology ; Apoptosis ; Biolistics ; Cell Line, Tumor ; Gene Products, rev ; physiology ; Genes, env ; physiology ; Genetic Vectors ; Humans ; Keratinocytes ; metabolism ; Plasmids ; Receptors, Tumor Necrosis Factor, Type I ; genetics

The Tagsk1 (Triticum asetium L. glycogen synthase kinase 1) gene derived from the genome of wheat salt-tolerance mutant RH8706-49 was cloned by PCR. The special primers designed according to full length cDNA sequence of Tagsk1 (AF525086). A binary expression vector pBI121-gsk1 containing Gus and Tagsk1 was constructed. And pBI121-gsk1 was introduced into the callus induced from mature embryos of salt-sensitive wheat H8706-34 and cv. China Spring by particle bombardment. The transformed callus were screened by Kanamycin and 0.5% NaCl. The salt-tolerance callus were obtained, which showed higher ability of salt-tolerance and could diffirentiate roots and buds on the medium containing 0.5% NaCl.
Adaptation, Physiological ; Biolistics ; DNA, Plant ; genetics ; Glycogen Synthase Kinases ; genetics ; Mutation ; Plant Proteins ; genetics ; Plants, Genetically Modified ; Salt-Tolerant Plants ; genetics ; Seeds ; genetics ; Sodium Chloride ; metabolism ; Transformation, Genetic ; Triticum ; enzymology ; genetics ; physiology

OBJECTIVETo investigate the inhibitory effect of DNA vaccine immunization on neu-overexpressed melanoma growth in prophylactic treatment and anti-lung-metastasis experiments in C57BL/6 mice.

METHODSpcDNA-neu transfected into B16F10 with transfection reagent Fugene 6, neu-overexpressed cell clone B16F10-neu was selected with limited dilution method. The growth curve was drawn to analyse its proliferating character in vitro. With Helios gene gun system, DNA vaccine pWRG-neu was immunized to 8-week-old C57BL/6 mice in the shaved abdominal skin for 3 times at two-weekly interval. After immunization, the life span was analyzed. Using MTT assay, the cytolysis activity of the DNA immunized mice spleen cells was compared.

RESULTSOne clone of neu-overexpressed B16F10-neu was selected and its proliferating character was the same as B16F10 and B16F10-pcDNA. In prophylactic, treatment and anti-lung-metastasis experiments, gene gun-mediated pWRG-neu immunization could exhibit antitumor effects. The growth and metastasis of neu-overexpressed melanoma was reduced dramatically. The spleen cells of the immuned mice showed cytotoxic T lymphocyte (CTL) activity.

CONCLUSIONGene gun-mediated gene transfer is effective and practicable. DNA vaccine pWRG-neu is potent in preventing subsequent tumor cells challenge, inhibiting the tumor growth and metastasis.

Animals ; Biolistics ; Cell Line, Tumor ; Cytotoxicity, Immunologic ; Genes, erbB-2 ; Immunization ; Lung Neoplasms ; prevention & control ; secondary ; Melanoma, Experimental ; metabolism ; pathology ; therapy ; Mice ; Mice, Inbred C57BL ; Neoplasm Transplantation ; Plasmids ; Receptor, ErbB-2 ; metabolism ; T-Lymphocytes, Cytotoxic ; immunology ; Vaccines, DNA