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At least 253 records · Page 14Linked to original sources

Direct gene transfer in skeletal muscle: plasmid DNA-based immunization against the hepatitis B virus surface antigen.

Direct gene transfer by intramuscular injection of plasmid DNA encoding an antigenic protein may be used for the purpose of immunization. DNA-based immunization may be of value for basic immunological research and vaccine development. Several factors influence the uptake and expression of plasmid DNA in skeletal muscle, which in turn influence the immune response to the expressed protein. Physical barriers and other factors may impede diffusion of the DNA within the muscle tissue or its entry into the muscle fibres. Although the efficiency of gene transfer in normal mouse muscle is low (< 100 fibres per injection site), a humoral response to the hepatitis B surface antigen (HBsAg) is obtained after expression of a transferred gene. Direct gene transfer is ten times more efficient in regenerating than in normal mouse muscle. DNA-based immunization in such regenerating muscles results in an earlier and stronger humoral response to HBsAg than is seen in normal mature muscle. A needleless jet injection system (Biojector) is able to deliver DNA into normal muscle in rats and rabbits such that a substantial immune response is obtained.

Animals↗

[Evaluation of potential risks of abrasive water jet osteotomy in-vivo].

Since the 80's the water jet scalpel is an established tool in some surgical fields. It is used in particular in visceral surgery for preparation of parenchymatous organs. By the addition of biocompatible abrasives, this technique is able to effectively machine hard biological tissues. Free defined cutting geometries can be realised in a non contact process. Therewith this method has crucial advantages compared to conventional osteotomy techniques and gives new impulses to the development in endoprosthetics and correction osteotomies of hollow bones. In the presented work the new developed abrasive water injection jet (AWIJ) was used the first time for in-vivo osteotomies. Aim of this study was the detection of potential thrombembolic effects and wash in effects of the cutting fluid. Hollow bones of the fore and hind leg of 20 house pigs were treated with the new cutting technique. Intraoperative documentation of relevant vital parameters was performed by a multi monitoring system. Thrombembolic effects during the osteotomy were detected by transthoracic Doppler ultrasonography and transesophagale echocardiography. The hollow bones were prepared in consideration of the vascularisation's protection especially in respect to the venous flow. Thrombembolic effects with temporary haemodynamic respectively respiratory consequences could be detected exclusively by using the so called "3-component jet", which consists of 90 vol % of air. The usage of an abrasive suspension enables the airfree dosing of dry soluable abrasives. Thrombembolic effects could not be monitored in this case. Intramedullary fluid in-wash effects as well as resulting electrolytic disorders could not be proven. For abrasive waterjet osteotomies with 3 component jet a relevant risk of thrombembolic effects could be shown. This knowledge has also to be considered for abdominal and neurosurgical applications in the future. Due to the usage of an abrasive suspension this risk can fully be avoided.

Animals↗

[Study of pressure and FeCO2 during ventilation by injection (preliminary note)].

This study, carried out in nine patients, attempted to judge the efficacy and possible inocuity of ventilation by injection (jet ventilation), firstly on capnography and. secondly, on recordings of intra-tracheal pressure. The frequency of six jets per minute, is that which, under the conditions of the trial, ensures the best removal of CO2 and the maintenance of stable CO2 levels in the trachea. Although pressures recorded in the airways varied between 15 and 40 torrs, the finding of very high peaks of pressure in certain cases, makes the authors somewhat reserved concerning the security of the method when the free reflux of gas is liable to be inhibited.

Bronchoscopy↗

Animal-free production of ccc-supercoiled plasmids for research and clinical applications.

The topological structure of plasmid DNA can be characterized by capillary gel electrophoresis (CGE analysis)-an important tool for quality control and stability assessments in DNA storage or application. Hence, a large-scale manufacturing process was developed that allows the removal of undesired open circular (oc) or linear plasmid topologies, bacterial genomic DNA, RNA, proteins as well as lipopolysaccharides (endotoxins) and results in obtaining supercoiled (covalently closed circular, ccc) plasmid DNA in a pure form without using any animal-derived substances. Using CGE, the development and in-line monitoring for pharmaceutical plasmid production starting from fermentation control throughout the whole manufacturing process including the formulated and filled product can be performed the first time in a way conforming to good manufacturing practices (GMP). Plasmid stability data were obtained from analysis of shear effects influencing the plasmid quality in DNA drug delivery formulation and application (e.g. gene gun or jet injection). The physical stability of plasmid DNA is for the first time evaluated in DNA storage experiments on the level of different plasmid forms.

DNA, Superhelical↗

Genetic vaccination approaches against malaria based on the circumsporozoite protein.

Malaria is the world's major parasitic disease, for which effective control measures are urgently needed. Despite considerable efforts, no successful vaccine against malaria has been developed so far. The method of DNA-based immunization offers the possibility to induce both antibody- and cell-mediated immune responses to a variety of antigens. The flexibility of the DNA vaccine technology permits the combination of several antigens from different developmental stages of the parasite's complicated life cycle. This review covers the development of DNA-based immunization against malaria from initial experiments in small animals to recently conducted clinical studies. Focusing on one of the best characterized malaria vaccine candidate antigens, the circumsporozoite protein, an overview of strategies to enhance vaccine efficacy is provided. Advanced application methods such as the gene gun technology or the needle-less jet injection device are described. As DNA vaccination represents a relatively new methodology, safety concerns associated with planned clinical applications are discussed. In summary, this novel type of vaccine has to be considered as a promising tool for future malaria vaccination strategies.

Animals↗

Measles vaccination in Zaïre--when and how?

Of 121 children vaccinated for measles in Zaïre, antibody studies revealed that 69% sero-converted. These included 53% of children vaccinated by two shots of a dermojet (0.2 ml i.d.) and 80% of children vaccinated by 0.5 ml subcutaneously. Whilst a dermojet gives less good results, a decision on its use needs to be made in each individual situation, particularly taking into account the quantity of vaccine available for the number of children presenting for vaccination. At six months of age 59% of children sero-converted. This did not reach 100% until 16 months of age. In view of the young age of children getting measles in Zaïre, there would seem to be value in vaccinating at six months, but this needs to be repeated at 16 months if full cover is required.

Age Factors↗

Adjunctive color Doppler ultrasonography in second-trimester transabdominal amnioinfusion.

Transabdominal amnioinfusion improves the diagnostic accuracy of ultrasonography in pregnancies complicated by second-trimester oligohydramnios. Needle localization may be difficult because of patient obesity or the absence of an acoustic window. The two cases presented demonstrate that color Doppler imaging facilitates amnioinfusion by visualizing the injection jet of free-flowing infusate, confirming intraamniotic needle placement.

Adult↗

Stability analysis for long-term storage of naked DNA: impact on nonviral in vivo gene transfer.

The transfer of naked DNA is gaining growing acceptance for nonviral gene therapy. Integrity and stability of the DNA used in nonviral gene therapy is known to be decisive for efficacy of gene transfer and transgene expression. Thus, preclinical and clinical studies require the safe storage of DNA preparations to ensure defined quality and conformation. To evaluate the influence of potentially destructive processes on plasmid DNA associated with long-term storage, capillary gel electrophoresis (CGE) analysis of the LacZ-expressing pCMVbeta plasmid over a period of 13 months was performed. The CGE analysis revealed that stable storage conditions at -80 degrees C prevent an increase in open circular (oc) plasmid, preserving the covalently closed circular (ccc) form, which is sought for efficient gene transfer. By contrast, long-term storage of plasmid DNA at 4 degrees C leads to the rapid decline of the ccc form and the increase of oc and linear DNA molecules. The use of naked DNA stored for 1, 2, or 13 months at -80 degrees C showed similar in vivo transfer efficiencies by jet-injection. Therefore, analysis of plasmids by CGE allows the reliable determination of integrity and distribution of the topology of the DNA by quantitative means.

Animals↗

DNA mucosal HIV vaccine in humans.

This is a demonstration of immune activation by delivery of genetic vaccines in human mucosa. We analyzed the local and systemic responses in HIV-1 infected individuals following intraoral jet-injections of HIV-1 DNA constructs encoding the nef, rev, and tat regulatory genes. The immunological responses of the oral mucosa may be representative of other mucosal sites and was therefore selected for induction of mucosal reactivity by DNA immunization. The oral and intramuscular routes induced specific systemic T cell proliferative responses. Immunohistochemical analysis of oral biopsies 2 days after immunization revealed increased levels of granulocytes and T cells as well as expression of HLA-DR. T cell markers for CD3 +, CD4 + and CD8 + were significantly increased in the vaccinated mucosa. Vaccine-specific local and systemic antibodies were present during the immunization. However, increases were neither seen in the local or systemic titer nor in the B-cell accumulation in response to the immunizations. The presence of HIV-1 plasmid DNA was observed in mucosal biopsies as well as local proinflammatory T lymphocyte immune responses with predominantly IL-2 expression in the oral mucosal transudate.

AIDS Vaccines↗

Immunization to protect the US Armed Forces: heritage, current practice, and prospects.

Americans serving with the US Armed Forces need protection from the dangerous infections that they can contract during training, based on occupation, during overseas deployment, or because of underlying health status. For over 230 years, the military health-care system has immunized troops to protect them personally and to help them accomplish their missions. Military researchers have invented, developed, and improved vaccines and immunization delivery methods against more than 20 diseases. This article consolidates content from several previous historical reviews, adds additional sources, and cites primary literature regarding military contributions and accomplishments. Discussion emphasizes smallpox, typhoid fever, tetanus, influenza, meningococcal disease, adenovirus, yellow fever, pneumococcal disease, and anthrax. Delivery issues include documentation, simultaneous immunization, seroscreening, safety surveillance, jet injection, and cold-chain management. Immunization policies for each major US conflict are described. Military immunization programs need to be individualized on the basis of personal contraindications and prior immunity. The proper conduct of military immunization programs respects the need for detailed education of military personnel, maximizes quality in immunization delivery, and supports quality clinical care to prevent and treat adverse events after immunization. Military immunization programs maintain the health of soldiers, marines, sailors, airmen, and coast guardsmen, the resources most critical to military success.

Bacterial Vaccines↗

Field trial of an inactivated Mycoplasma pneumoniae vaccine. I. Vaccine efficacy.

The efficacy of an inactivated Mycoplasma pneumoniae vaccine was evaluated in a double-blind study of 7,861 Marine Corps recruits at Parris Island, South Carolina. Vaccine was administered to half for the volunteers in a 1-ml dose by a jet-injection device, and phosphate-buffered saline was administered similarly to control subjects. Twenty-one vaccinees (5.3 per 1,000) and 43 recipients of placebo (10.9 per 1,000) were hospitalized with pneumonia; the incidence of illness among the two groups indicated a 51% overall protective efficacy for the vaccine (x2 = 7.49; P less than 0.01). The refined data for pneumonia due to M. pneumoniae showed 67% protective efficacy when serologic data were employed (x2 = 7.84; P = 0.005) and a 42% protective efficacy (x2 = 1.80; P greater than 0.10) when data from cultures for M. pneumoniae were employed. Vaccinees with pneumonia due to M. pneumoniae suffered no increased illness compared to controls, suggesting no hypersensitization with natural illness following the inactivated vaccine. Only when serologic data were analyzed did it appear that the M. pneumoniae vaccine protected against M. pneumoniae specific bronchitis (35% efficacy) but the difference was not statistically significant (x2 = 1.28; P greater than 0.20).

Bacterial Vaccines↗

Protective efficacy of an inactivated Mycoplasma pneumoniae vaccine.

The protective efficacy of a formalin-inactivated Mycoplasma pneumoniae vaccine was evaluated in a double-blind fashion in 7,861 Marine Corps recruits at Parris Island, South Carolina. Vaccine, administered in a 1-ml dose by a jet-injection device, was glass-grown and contained 264 microgram of protein nitrogen/ml. Phosphate-buffered saline with formalin was injected as a control. Systemic reactions to injection were similar in both groups, but the percentage of vaccinees with erythema (51%) and induration (52%) at 24 hr was significantly greater than the percentage of controls (2%) with these reaction (P less than 0.001). Twenty-one (0.5%) of 3,930 vaccinees and 43 (1.1%) of the 3.931 placebo recipients were hospitalized with pneumonia (chi2=7.61; P less than 0.01). Ten of 21 vaccinees and seven of 43 controls with pneumonia had a positive pharyngeal culture for M. pneumoniae (chi2=1.69; P =0.20), and fourfold rises in titer of serum antibody were noted in five of 14 vaccinees and in 15 of 28 placebo recipients with pneumonia (chi2=7.90; P less 0.0005). Therefore, vaccine efficacy for M. pneumoniae-specific pneumonia was 42% as determined by cultures and 67% by serologic tests. The vaccine showed no protective efficacy for M. pneumoniae-specific bronchitis or for M. pneumoniae pharyngeal carriage in recrutis in training.

Antibodies, Bacterial↗

Assessment of the biological performance of the needle-free injector INJEX using the isolated porcine forelimb.

BACKGROUND: The development and utilization of novel needle-free injection devices in order to minimize needle stick injuries make increasing demands for suitable assay systems, which reflect the physiological situation in humans as close as possible. OBJECTIVES: It was therefore the goal of the present study to test the biological performance of a needle-free injector (INJEX) by the use of porcine skin as a model with a high predictive value for the feasibility in humans because of its close similarity to human skin. METHODS: In order to use porcine skin in the context of the underlying tissues, the isolated porcine forelimb was chosen as an assay model for use with the INJEX injector. Ink or the fluorescent dye fluorescein-isothiocyanate was injected and the penetration depth was determined metrically and dye distribution histologically. To assess the resorption of heparin, needle injection was compared with needle-free injection in a perfused limb model. RESULTS: Increasing amounts of ink increasingly penetrated into subcutaneous tissue layers in a cone-shaped manner mainly following lead structures. Penetration was hampered by skin thickness and by the deep muscle fascia, which served as a penetration barrier. Resorption of heparin was similar irrespective of injection by the use of a needle or the INJEX device. CONCLUSIONS: The isolated porcine forelimb serves as a versatile tool for the assessment of the biological performance of needle-free injection devices such as INJEX. Further studies are necessary to correlate the model for drug delivery in humans.

Absorption↗

Influence of concentration and injection volume on the bioavailability of subcutaneous growth hormone: comparison of administration by ordinary syringe and by injection pen.

In order to study whether the bioavailability of subcutaneously injected growth hormone (GH) is dependent on the concentration/volume injected, the relative GH bioavailability was evaluated in 14 GH-deficient patients. In a cross-over study the patients received, in random order two separate subcutaneous GH injections (Norditropin) 4 IU administered by means of an ordinary syringe (4 IU ml) and an injection pen with cartridge (Nordiject 24) (12 IU/ml). Blood samples were drawn over a 14 hr period and assayed for serum concentrations of GH and IGF-I. The mean value (+/- S.D.) of the relative absorption fraction (Fpen/sy) was 1.09 +/- 0.39. Mean values of Cmax were 8.6 ng/ml +/- 4.8 and 8.3 ng/ml +/- 7.5 for syringe and pen respectively. Corresponding values for Tmax were 311 min. +/- 131 for syringe and 309 min. +/- 104 for pen. Although a considerable interindividual variation was seen, the relative absorption fraction did not differ significantly from 1 (2 P = 0.78). Further there was no significant difference in neither Cmax (2 P = 0.39) nor Tmax (2 P = 0.55). IGF-I serum profiles tended to be higher following syringe compared to pen injection (2 P = 0.054). On the basis of this study we conclude that in this dosage regimen. GH bioavailability following pen injection equals that of injection by syringe (i.e. no effect of a three fold increase/decrease in GH concentration/volume respectively).

Adult↗