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At least 397 records · Page 22Linked to original sources
PubMed1994

Immunization with plasmid DNA using a pneumatic gun.

We characterize a method by which the Med-E-Jet pneumatic vaccination gun can be used to propel intact, supercoiled plasmid DNA through skin and into skeletal muscles of mice. Intramuscular injection of plasmids containing the firefly luciferase gene linked to the human cytomegalovirus promoter resulted in the expression of several hundred picograms of luciferase enzyme in quadriceps muscles. Intramuscular injections of a plasmid containing the influenza A nuclear protein gene regulated by the same promoter resulted in the generation of potent and specific anti-nuclear protein humoral and cellular immune responses. This convenient and rapid injection method would be well-suited for genetic immunization of humans.

Animals↗
PubMed1992

[Revaccination of schoolchildren with BCG-M vaccine and use of a new model of BI-19 jet injector].

A comparative analysis of the effectiveness of revaccination of 1595 schoolchildren with the BCG and BCG-M vaccine is given in relation to the method of vaccine administration and revaccination frequency (1st revaccination was given in the 1st and 2nd in the ninth form). Both vaccines were found to be equally effective both in the development of a postvaccination skin sign and postvaccination allergy. The method of BCG vaccine administration (with a jet injector and needle syringe) had no essential influence on the revaccination effect. The advantage of a new BI-19 jet injector used for tuberculin diagnosis consisted in that there was no need to adjust the results of tuberculin diagnosis as was the case with a previous BI-IM jet injector.

Age Factors↗
PubMed2002

Transdermal drug delivery by jet injectors: energetics of jet formation and penetration.

PURPOSE: Pressure-driven jets have been used for intradermal delivery of a variety of drugs. Despite their introduction into clinical medicine, variability and occasional bruising have limited their widespread acceptance. Although numerous clinical studies of jet injectors have been reported in the literature, surprisingly little is known about the mechanisms of jet penetration into the skin. In this article, we report results of our studies aimed at determining the dependence of drug delivery on jet velocity and diameter. These studies were performed using two experimental models, porcine skin and human skin. Our rationale for using two models was to explore the possibility of using porcine skin as a model for human skin. METHODS: Dermal penetration of jets possessing a range of diameters from 76 microm to 559 microm and a range of velocities from 80 m/s to 190 m/s was studied into human and porcine skin. Penetration was quantified using radiolabeled mannitol. Pressure and velocity of the jets were measured using a calibrated pressure transducer and high-speed photography. RESULTS: Penetration of the jet into the skin was determined by two main parameters, jet diameter and average jet velocity. Substantial variation in jet penetration into porcine skin was observed for skin pieces obtained from different anatomic locations. For porcine skin, a parabolic dependence of jet delivery on velocity and diameter was observed. The threshold velocity is suggested to be between 80 and 100 m/s for a jet diameter of 152 microm. Above the threshold velocity, the delivery increased for velocities up to 150 m/s, after which delivery decreased with increasing velocity. At a constant velocity of 150 m/s, jet delivery exhibited a maximum at a diameter of 152 microm. Results obtained with human skin were qualitatively similar but quantitatively different. The threshold velocity for jet penetration into human skin was comparable with that in porcine skin; however, the maxima observed in jet delivery into porcine skin with respect to jet velocity was not apparent for human skin over the range of velocities explored. CONCLUSIONS: These studies offer a quantitative analysis of jet penetration into the skin.

Administration, Cutaneous↗
PubMed1990

The effective tracheal diameter that causes air trapping during jet ventilation.

Jet ventilation consists of injection of gas at high flow rates through a small-diameter tracheal catheter. Air trapping (increase in end-expiratory lung volume) can occur during jet ventilation if the diameter of the trachea proximal to the tracheal catheter tip is too small (at least at one point in the trachea) to permit complete exhalation of the tidal volume around the tracheal catheter (ie, through the effective tracheal diameter). A mechanical lung model was used to determine the critical effective tracheal diameter at which air trapping starts to occur during jet ventilation. The experiment allowed derivation of a multivariable equation, namely: [formula: see text] to express the tidal volume produced by jet ventilation (y) as a function of gas flow rate (C), jet injection time (D), lung compliance (B), upper airway resistance (A), and effective tracheal diameter (E). As A to D increased and E decreased, y increased. More importantly, exhalation time was measured over the full range of values for A to E, and it was found that for every possible combination of values for A to D, there was always a unique critical effective tracheal diameter, 4.0 to 4.5 mm, that began to cause a very large increase in expiratory time (and with a sufficiently rapid respiratory rate [greater than 12 beats/min in this experiment], air trapping). Thus, when lung/jet ventilation factors tend to promote entry of jetted gas into the lungs (increased A to D, decreased E), even a small tidal volume has difficulty exiting the lung, if E is smaller than 4.5 mm.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway Resistance↗