Biomedical subjects

Ching-Hua Wang

Publications and source records attributed to Ching-Hua Wang.

4 recordsLinked to original sources

PubMed2006

Pulmonary delivery of insulin by liposomal carriers.

Growing attention has been given to the potential of a pulmonary route as a non-invasive administration for systemic delivery of therapeutic agents (mainly peptides and proteins). The lungs provide a large absorptive surface area, extremely thin absorptive mucosal membrane, and good blood supply. The non-invasive nature of this pathway makes it especially valuable for the delivery of large molecular protein. However, pulmonary delivery of peptides and proteins is complicated by the complexity of the anatomic structure of the human respiratory system and the effect of disposition exerted by the respiration process. In this study, novel nebulizer-compatible liposomal carrier for aerosol pulmonary drug delivery of insulin was developed and characterized. Experimental results showed that insulin could be efficiently encapsulated into liposomes by preformed vesicles and detergent dialyzing method. The optimal encapsulation efficiency was achieved when 40% ethanol was used. The particle size of liposomal aerosols from ultrasonic nebulizer approximated to 1 mum. Insulin was stable in the liposomal solution. Animal studies showed that plasma glucose level was effectively reduced when liposomal insulin was delivered by inhalation route of using aerosolized insulin-encapsulated liposomes. Including fluorescent probe (phosphatidylethanolamine-rhodamine) into liposome, we found that the liposomal carriers were effectively and homogeneously distributed in the lung aveolar. Liposome-mediated pulmonary drug delivery promotes an increase in drug retention-time in the lungs, and more importantly, a reduction in extrapulmonary side-effects which invariably results in enhanced therapeutic efficacies.

Administration, Inhalation↗

PubMed2006

A comparison of regional and systemic humoral immune responses to a nematode infection.

The kinetics of humoral immune response against Trichinella spiralis (TS) was characterized with immunofluorescence assay. The mesenteric lymph nodes (MLN) and the spleen of infected rats were examined for concurrent expression of multiple antibody (Ab) isotypes from day 1 to day 15 after infection. The tissues were processed and stained with either a pan-B cell marker (OX33) conjugated with rhodamine (XRITC) or combinations of dual monoclonal Ab probes plus A secondary Ab conjugated with XRITC or fluorescein (FITC). As compared to the uninfected controls, the spleen and the MLN showed significant proliferation of dual-Ab expressing B cells (Debc) on days 5 and 7, respectively. During the immune response, only minimal numbers of B cells expressed single Ab isotype while most B cells expressed more than one isotypes of Ab. When combining all the numbers of Debc within each tissue for each respective days, and comparing those numbers with the total numbers of B cells that were OX33+ in the serial sections of the same tissue specimens, the combined Debc in the spleen were > 6 times higher than the OX33 labeled B cells on day 10, and the Debc in MLN were > 3 times higher than the OX33+ B cells on day 10. Our results thus indicate that the Debc most likely expressed more than two Ab isotypes during the peak days of the humoral immune response to the parasite and this phenomenon occurred in both regional and systemic lymphoid tissues.

Analysis of Variance↗

PubMed2004

Rapidity and multiplicity of synthesis and expression of immunoglobulin isotypes by B lymphocytes in the small intestine.

An immunofluorescence double labeling assay was used to examine the kinetics of intestinal B lymphocytes with concurrent expression of multiple antibody isotypes in the mucosal tissues of rats infected with Trichinella spiralis (TS) muscle larvae for 1 to 15 days. As compared to the uninfected controls (day 0), the non-Peyer's patch tissues of the small intestine contained a significantly increased number of dual antibody-expressing B cells as early as 3 days after infection with a maximum proliferation of these B cells on days 7 and 10. These results indicate the rapidity of B cell response in the small intestine. Similar results were observed in the germinal centers of the Peyer's patches. The non-germinal centers of the Peyer's patch tissues showed delayed kinetics in B cell activation which occurred 10 days after infection. Quantification of the total number of B cells in these tissues was also carried out by staining the CD45RA marker on B cells with the OX33 monoclonal antibody. When comparing the total numbers of B cells with the numbers of B cells expressing dual isotypes of antibodies, our results showed the numbers of dual-expressing B cells (IgA:IgE, IgM:IgE, IgG1:IgE, IgG2a:IgE, IgG2b:IgE, and IgG2c:IgE), when combined, were over 7 times that of the total number of OX33-labeled B cells on day 7 in the small intestine. The dual-expressing B cells in the Peyer's patch-germinal center were more than 5 times that of the OX33-labeled B cells on day 15. These results therefore suggest that the dual-expressing B cells most likely synthesized and expressed more than two isotypes of antibodies during the peak days of the humoral response. Such phenomenon was not observed in non-germinal centers of the Peyer's patch tissues.

Animals↗

PubMed2003

Encapsulating protein into preformed liposomes by ethanol-destabilized method.

This study describes a highly efficient method for encapsulating protein drugs into liposomes without using toxic solvents such as chloroform. Large unilamellar vesicles (LUVs) were formed by the ethanol injection method. The effects of composition of phospholipid, buffer concentration, incubation time, incubation temperature, drug loading, ethanol content, and the presence of poly(ethylene) glycol (PEG) lipids on the entrapment efficiency of protein were investigated. It was shown that these preformed LUVs could be induced to entrap protein drugs in the presence of ethanol. Protein could be efficiently encapsulated into liposomes. The interaction of the liposomes with proteins leads to the formation of multilamellar liposomes ranging in size from 70 to 120 nm, only slightly bigger than the parent LUVs from which they originated. Protein drugs were stable in the liposomal solution. There is no significant activity loss during the encapsulation process. The optimal encapsulation efficiency was achieved when 30% approximately 40% ethanol was used in encapsulating protein drugs. Due to the steric hindrance, LUVs containing a PEG coating will dramatically reduce the encapsulation efficiency, even in liposomes containing very low amount of PEG.

Buffers↗