Biomimetic characteristics of mussel adhesive protein-loaded collagen membrane in guided bone regeneration of rabbit calvarial defects

PURPOSE: The aim of the present study was to evaluate the biocompatibility and barrier function of mussel adhesive protein (MAP)-loaded collagen membranes in guided bone regeneration (GBR). METHODS: Eight male New Zealand white rabbits were used. Four circular defects (diameter: 8 mm) were created in the calvarium of each animal. The defects were randomly assigned to 1) a negative control group, 2) a cyanoacrylate (CA)-loaded collagen membrane group (the CA group), 3) a MAP-loaded collagen membrane group (the MAP group), and 4) a group that received a polycaprolactone block with MAP-loaded collagen membrane (the MAP-PCL group). Specimens were harvested at 2 weeks (n=4) and 8 weeks (n=4) postoperatively for observational histology and histometric analysis. RESULTS: In the histologic analysis, MAP was completely absorbed without any byproducts. In contrast, some of the CA adhesive remained, showing an inflammatory reaction, at 8 weeks. In the MAP-PCL group, the MAP-loaded collagen membranes served as a barrier membrane despite their fast degradation in GBR. No significant difference was found in the amount of new bone between the MAP-PCL and MAP groups (1.82±0.86 mm2 and 2.60±0.65 mm2, respectively). CONCLUSIONS: The MAP-loaded collagen membrane functioned efficiently in this rabbit calvarial GBR model, with excellent biocompatibility. Further research is needed to assess clinical applications in defect types that are more challenging for GBR than those used in the current model.

Bone Regeneration Using Block-type Deproteinized Porcine Bone Mineral with Collagen Membrane Using 3,4-Dihydroxyphenylalanine as Bone Adhesive

PURPOSE: The purpose of this study was to assess the adhesiveness and cytotoxicity of 3, 4-dihydroxyphenylalanine (DOPA), and to evaluate the role of collagen membrane with DOPA in the guided bone regeneration. MATERIALS AND METHODS: Peel resistance and cell cytotoxicity test were performed. Four defect types in nine rabbit calvaria were randomly allocated: i) control, ii) membrane, iii) deproteinized porcine bone mineral (DPBM) covered by membrane with DOPA, and iv) DPBM covered by membrane with cyanoacrylate. Animals were sacrificed at 2 (n=4) and 8 weeks (n=5) for microcomputed tomography and histomorphometric analysis. DOPA showed low peel resistance but high cell viability. RESULT: Cyanoacrylate and DOPA groups showed significantly higher mineralized tissue volume (MTV) compared to control and membrane groups at 2 weeks (P < 0.05). At 8 weeks, DOPA group showed the highest MTV. Significantly higher new bone area was found in DOPA group at 8 weeks (P < 0.05). Bone formation increased from 2 to 8 weeks in DOPA group (P < 0.05). CONCLUSION: DOPA showed high cell viability and in vivo study revealed predictable performance in bone regeneration.

Influence of Implant Surface Coated with pH Buffering Agent on Early Osseointegration

PURPOSE: Surface treatment with pH buffering agent has been developed to achieve higher and faster osseointegration. The aim of this study was to evaluate its influence by measuring removal torque and analyzing histological characteristics. MATERIALS AND METHODS: Titanium implants with following surfaces were used in this study: sand-blasted acid-etched (SA) surface (SA group as control I group), SA surface in calcium chloride aqueous solution (CA group as control II group) and SA surface coated with pH buffering agent (pH group as test group). Removal torque test after 2 weeks and bone-to-implant contact and bone area analyses at 2 and 4 weeks were performed. RESULT: The rotational torque values at 2 weeks were significantly higher in pH group (107.5±6.2 Ncm, P < 0.05). The mean values of bone-to-implant contact at 2 and 4 weeks were both higher in pH group (93.0%±6.4% at 2 weeks, 88.6%±5.5% at 4 weeks) than in SA group (49.7%±9.7% at 2 weeks, 47.3%±20.1% at 4 weeks) and CA group (73.7%±12.4% at 2 weeks, 72.5%±10.9% at 4 weeks) with significances (P < 0.05). The means of bone area showed significantly higher numbers in pH group (39.5%±11.3% at 2 weeks, 71.9%±10.9% at 4 weeks, P < 0.05). CONCLUSION: Our findings demonstrated that surface modification with pH buffering agent improved early osseointegration with superior biomechanical property.

Effect of Harderian adenectomy on the statistical analyses of mouse brain imaging using positron emission tomography

Positron emission tomography (PET) using 2-deoxy-2-[18F] fluoro-D-glucose (FDG) as a radioactive tracer is a useful technique for in vivo brain imaging. However, the anatomical and physiological features of the Harderian gland limit the use of FDG-PET imaging in the mouse brain. The gland shows strong FDG uptake, which in turn results in distorted PET images of the frontal brain region. The purpose of this study was to determine if a simple surgical procedure to remove the Harderian gland prior to PET imaging of mouse brains could reduce or eliminate FDG uptake. Measurement of FDG uptake in unilaterally adenectomized mice showed that the radioactive signal emitted from the intact Harderian gland distorts frontal brain region images. Spatial parametric measurement analysis demonstrated that the presence of the Harderian gland could prevent accurate assessment of brain PET imaging. Bilateral Harderian adenectomy efficiently eliminated unwanted radioactive signal spillover into the frontal brain region beginning on postoperative Day 10. Harderian adenectomy did not cause any post-operative complications during the experimental period. These findings demonstrate the benefits of performing a Harderian adenectomy prior to PET imaging of mouse brains.

Estimation of Internal Motion for Quantitative Improvement of Lung Tumor in Small Animal / 의학물리

The purpose of this study was to estimate internal motion using molecular sieve for quantitative improvement of lung tumor and to localize lung tumor in the small animal PET image by evaluated data. Internal motion has been demonstrated in small animal lung region by molecular sieve contained radioactive substance. Molecular sieve for internal lung motion target was contained approximately 37 kBq Cu-64. The small animal PET images were obtained from Siemens Inveon scanner using external trigger system (BioVet). SD-Rat PET images were obtained at 60 min post injection of FDG 37 MBq/0.2 mL via tail vein for 20 min. Each line of response in the list-mode data was converted to sinogram gated frames (2~16 bin) by trigger signal obtained from BioVet. The sinogram data was reconstructed using OSEM 2D with 4 iterations. PET images were evaluated with count, SNR, FWHM from ROI drawn in the target region for quantitative tumor analysis. The size of molecular sieve motion target was 1.59x2.50 mm. The reference motion target FWHM of vertical and horizontal was 2.91 mm and 1.43 mm, respectively. The vertical FWHM of static, 4 bin and 8 bin was 3.90 mm, 3.74 mm, and 3.16 mm, respectively. The horizontal FWHM of static, 4 bin and 8 bin was 2.21 mm, 2.06 mm, and 1.60 mm, respectively. Count of static, 4 bin, 8 bin, 12 bin and 16 bin was 4.10, 4.83, 5.59, 5.38, and 5.31, respectively. The SNR of static, 4 bin, 8 bin, 12 bin and 16 bin was 4.18, 4.05, 4.22, 3.89, and 3.58, respectively. The FWHM were improved in accordance with gate number increase. The count and SNR were not proportionately improve with gate number, but shown the highest value in specific bin number. We measured the optimal gate number what minimize the SNR loss and gain improved count when imaging lung tumor in small animal. The internal motion estimation provide localized tumor image and will be a useful method for organ motion prediction modeling without external motion monitoring system.

Quantitative Assessment Technology of Small Animal Myocardial Infarction PET Image Using Gaussian Mixture Model / 의학물리

Nuclear medicine images (SPECT, PET) were widely used tool for assessment of myocardial viability and perfusion. However it had difficult to define accurate myocardial infarct region. The purpose of this study was to investigate methodological approach for automatic measurement of rat myocardial infarct size using polar map with adaptive threshold. Rat myocardial infarction model was induced by ligation of the left circumflex artery. PET images were obtained after intravenous injection of 37 MBq 18F-FDG. After 60 min uptake, each animal was scanned for 20 min with ECG gating. PET data were reconstructed using ordered subset expectation maximization (OSEM) 2D. To automatically make the myocardial contour and generate polar map, we used QGS software (Cedars-Sinai Medical Center). The reference infarct size was defined by infarction area percentage of the total left myocardium using TTC staining. We used three threshold methods (predefined threshold, Otsu and Multi Gaussian mixture model; MGMM). Predefined threshold method was commonly used in other studies. We applied threshold value form 10% to 90% in step of 10%. Otsu algorithm calculated threshold with the maximum between class variance. MGMM method estimated the distribution of image intensity using multiple Gaussian mixture models (MGMM2, em leader MGMM5) and calculated adaptive threshold. The infarct size in polar map was calculated as the percentage of lower threshold area in polar map from the total polar map area. The measured infarct size using different threshold methods was evaluated by comparison with reference infarct size. The mean difference between with polar map defect size by predefined thresholds (20%, 30%, and 40%) and reference infarct size were 7.04+/-3.44%, 3.87+/-2.09% and 2.15+/-2.07%, respectively. Otsu verse reference infarct size was 3.56+/-4.16%. MGMM methods verse reference infarct size was 2.29+/-1.94%. The predefined threshold (30%) showed the smallest mean difference with reference infarct size. However, MGMM was more accurate than predefined threshold in under 10% reference infarct size case (MGMM: 0.006%, predefined threshold: 0.59%). In this study, we was to evaluate myocardial infarct size in polar map using multiple Gaussian mixture model. MGMM method was provide adaptive threshold in each subject and will be a useful for automatic measurement of infarct size.

Imaging of Herpes Simplex Virus Type 1 Thymidine Kinase Gene Expression with Radiolabeled 5-(2-iodovinyl)-2'-deoxyuridine (IVDU) in Liver by Hydrodynamic-based Procedure / 핵의학분자영상

PURPOSE: Hydrodynamic-based procedure is a simple and effective gene delivery method to lead a high gene expression in liver tissue. Non-invasive imaging reporter gene system has been used widely with herpes simplex virus type 1 thymidine kinase (HSV1-tk) and its various substrates. In the present study, we investigated to image the expression of HSV1-tk gene with 5-(2-iodovinyl)-2'-deoxyuridine (IVDU) in mouse liver by the hydrodynamicbased procedure. MATERIALS AND METHODS: HSV1-tk or enhanced green fluorescence protein (EGFP) encoded plasmid DNA was transferred into the mouse liver by hydrodynaminc injection. At 24 h post-injection, RT-PCR, biodistribution, fluorescence imaging, nuclear imaging and digital wholebody autoradiography (DWBA) were performed to confirm transferred gene expression. RESULTS: In RT-PCR assay using mRNA from the mouse liver, specific bands of HSV1-tk and EGFP gene were observed in HSV1-tk and EGFP expressing plasmid injected mouse, respectively. Higher uptake of radiolabeled IVDU was exhibited in liver of HSV1-tk gene transferred mouse by biodistribution study. In fluorescence imaging, the liver showed specific fluorescence signal in EGFP gene transferred mouse. Gamma-camera image and DWBA results showed that radiolabeled IVDU was accumulated in the liver of HSV1-tk gene transferred mouse. CONCLUSION: In this study, hydrodynamic-based procedure was effective in liver-specific gene delivery and it could be quantified with molecular imaging methods. Therefore, co-expression of HSV1-tk reporter gene and target gene by hydrodynamic-based procedure is expected to be a useful method for the evaluation of the target gene expression level with radiolabeled IVDU.

Production and Evaluation of Immunoreactivity of Poly Lysine-Tagged Single Chain Fragment Variable (ScFv) Lym-1 Antibody for Direct Conjugation to Fluorescence Dye / 핵의학분자영상

PURPOSE: Small size of recombinant scFv antibody has many advantages such as rapid blood clearances and improved targeting antibodies to tumor region. On the other hand owing to small size, number of amino group is insufficient in conjugation with chelator and fluorescence labeling. This study is to introduce poly lysine tag to the C-terminal end of scFv lym-1 sequence for fluorescence chelator conjugation. MATERIALS AND METHODS: Poly lysine scFv lym-1 gene, cloned into pET-22b (+) vector, was expressed in E. coli BL21 (DE3) strain. Antibody purification was performed with Ni-NTA column and then size exclusion column chromatography. Expression and purification levels of poly lysine tagged scFv lym-1 antibody were confirmed by western blot analysis. I-124, I-125, I-131 and Tc-99m were used for radiolabeling of purified poly lysine scFv lym-1. Flow cytometry analysis of FITC conjugated poly lysine scFv lym-1 was performed for confirmation of immunoreactivity of human Burkitt`s lymphoma cells. RESULTS: Poly lysine scFv lym-1 antibody was purified through two steps and identified as molecular weight of 48 KDa. Radiolabeling yields of I-124, I-125, I-131 and Tc-99m into poly lysine scFv lym-1 were >99%, >99%, >95% and >99%, respectively. Flow cytometry analysis of poly lysine scFv and scFv lym-1 was showed similar immunoreactivity to human Burkitt`s lymphoma cells. CONCLUSION: Poly lysine tag was useful for the sufficient number of amino groups to scFv lym-1 antibody for chelator conjugation with minimizing loss of immunoreactivity.

Imaging of Lung Metastasis Tumor Mouse Model using 18FFDG Small Animal PET and CT / 핵의학분자영상

PURPOSE: The purpose of this study is to image metastaic lung melanoma model with optimal pre-conditions for animal handling by using [18F]FDG small animal PET and clinical CT. MATERIALS AND METHODS: The pre-conditions for lung region tumor imaging were 16-22 h fasting and warming temperature at 30 degrees C. Small animal PET image was obtained at 60 min postinjection of 7.4 MBq [18F]FDG and compared pattern of [18F]FDG uptake and glucose standard uptake value (SUVG) of lung region between Ketamine/Xylazine (Ke/Xy) and Isoflurane (Iso) anesthetized group in normal mice. Metastasis tumor mouse model to lung was established by intravenous injection of B16-F10 cells in C57BL/6 mice. In lung metastasis tumor model, [18F]FDG image was obtained and fused with anatomical clinical CT image. RESULTS: Average blood glucose concentration in normal mice were 128.0+/-23.87 and 86.0+/-21.65 mg/dL in Ke/Xy group and Iso group, respectively. Ke/Xy group showed 1.5 fold higher blood glucose concentration than Iso group. Lung to Background ratio (L/B) in SUVG image was 8.6+/-0.48 and 12.1+/-0.63 in Ke/Xy group and Iso group, respectively. In tumor detection in lung region, [18F]FDG image of Iso group was better than that of Ke/Xy group, because of high L/B ratio. Metastatic tumor location in [18F]FDG small animal PET image was confirmed by fusion image using clinical CT. CONCLUSION: Tumor imaging in small animal lung region with [18F]FDG small animal PET should be considered pre-conditions which fasting, warming and an anesthesia during [18F]FDG uptake. Fused imaging with small animal PET and CT image could be useful for the detection of metastatic tumor in lung region.

Translational Research Using Sodium/Iodide Symporter / 대한내분비학회지

No abstract available.

Tumor targeted gene therapy / 핵의학분자영상

Knowledge of molecular mechanisms governing malignant transformation brings new opportunities for therapeutic intervention against cancer using novel approaches. One of them is gene therapy based on the transfer of genetic material to an organism with the aim of correcting a disease. The application of gene therapy to the cancer treatment has led to the development of new experimental approaches such as suicidal gene therapy, inhibition of oncogenes and restoration of tumor-suppressor genes. Suicidal gene therapy is based on the expression in tumor cells of a gene encoding an enzyme that converts a prodrug into a toxic product. Representative suicidal genes are Herpes simplex virus type 1 thymidine kinase (HSV1-tk) and cytosine deaminase (CD). Especially, physicians and scientists of nuclear medicine field take an interest in suicidal gene therapy because they can monitor the location and magnitude, and duration of expression of HSV1-tk and CD by PET scanner.

The Relationship between Expression of the Sodium/iodide Symporter Gene and the Status of Hormonal Receptors in Human Breast Cancer Tissue / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: It has been reported that the sodium/iodide symporter (NIS) gene is expressed in several breast cancer tissues, suggesting the possibility of radionuclide imaging and therapy. However, the regulatory mechanism of NIS gene expression in breast cancer is not yet understood. To assess the relationship between the hormonal status and the NIS expression in breast cancer tissue, we investigated the NIS expression and correlated it to the expression of the thyrotropin receptor (thyroid stimulating hormone receptor, TSH-R), the estrogen receptor (ER) and the progesterone receptor (PR) in human breast cancer tissues. MATERIALS AND METHODS: Breast cancer tissues were obtained from 44 patients. Pathological examination showed 2 cases of Grade I, 17 of Grade II, 22 of Grade III, and 3 of unknown grade. We measured the expression of NIS and TSH-R genes by using RT-PCR and we measured the status of ER and PR by using immunohisto-chemistry. RESULTS: The NIS gene was expressed in 15 (34%) of the 44 breast cancer tissues. The NIS gene was expressed in 32% of the cases with TSH-R gene expression. The NIS gene was expressed in 40% of the breast cancer tissues with a positive PR and in 31% with a negative PR (p>0.05). It was positive for PR in 18% of the cases and negative for PR in 39% of the cases (p>0.05). CONCLUSION: The NIS gene is expressed in approximately one-third of the human breast cancer tissues. Its expression was not related to the presence of the TSH-R gene or hormonal receptors, ER and PR.

Expression of Sodium/iodide Symporter Transgene in Neural Stem Cells / 대한핵의학회잡지

PURPOSE: The ability to noninvasively track the migration of neural progenitor cells would have significant clinical and research implications. We generated stably transfected F3 human neural progenitor cells with human sodium/iodide symporter (hNIS) for noninvasively tracking F3. In this study, the expression patterns of hNIS gene in F3-NIS were examined according to the cultured time and the epigenetic modulation. MATERIALS AND METHODS: F3 human neural stem cells had been obtained from Dr. Seung U. Kim (Ajou University, Suwon, Korea). hNIS and hygromycin resistance gene were linked with IRES (Internal Ribosome Entry Site) under control of CMV promoter. This construct was transfected to F3 with Liposome. To investigate the restoration of hNIS gene expression in F3-NIS, cells were treated with demethylating agent (5-Azacytidine) and Histone deacetylase inhibitor (Trichostatin A: TSA). The expression of hNIS was measured by I-125 uptake assay and RT-PCR analysis. RESULTS: The iodide uptake of the F3-NIS was higher 12.86 times than F3 cell line. According to the cell passage number, hNIS expression in F3-NIS gradually diminished. After treatment of 5-Azacytidine and TSA with serial doses (up to 20micro M, up to 62.5nM, respectively) for 24 hours, I-125 uptake and mRNA of hNIS in F3-NIS were increased. CONCLUSION: These results suggest that hNIS transfected F3 might undergo a change in its biological characters by cell passage. Therefore, the gene expression of exogenous gene transferred human stem cell might be affected to the epigenetic modulation such as promoter methylation and Histone deacetylation and to the cell culture conditions.

General Perspectives on Molecular Imaging

Motecular imaging provides a visualization of normal as well as abnormal cellular processes at a molecular or genetic level rather than at the anatomical level. Molecular imaging is rapidly emerging and a multidisciplinary field coordinating medicine, molecular cell biology, chemistry, pharmacology, genetics, biomedical engineering, and physics. Conventional medical imaging methods utilize the imaging signals produced by nonspecific physico chemical interaction. However, molecular imaging methods utilize the imaging signals derived from specific cellular or molecular events. Because molecular and genetic changes precede anatomical change in the course of disease development, molecular imaging can detect early events in disease progression. Molecular imaging includes images of proteomics, metabolism, cellular biologic processes as well as genetics. In a narrow sense, molecular imaging means genetic imaging using imaging reporter genes. We can image diverse cellular processes including gene expression, proteinprotein interaction, signal transduction pathway, and monitoring of target cell distribution (cancer cells, immune cells, and stem cells) by imaging reporter gene. Molecular imaging methods are classified as optical imaging, nuclear imaging and magnetic resonance imaging. Each imaging modalities have their advantages and weaknesses. In the near future, through molecular imaging we can understand basic mechanisms of disease, and diagnose earlier and, subsequently, treat earlier intractable diseases such as cancer, neuro degenerative diseases, and immunologic disorders.

Introduction To Basic Molecular Biologic Techniques For Molecular Imaging Researches / 대한핵의학회잡지

Molecular imaging is a rapidly growing field due to the advances in molecular biology and imaging technologies. With the introduction of imaging reporter genes into the cell, diverse cellular processes can be monitored, quantified and imaged non-invasively in vivo. These processes include the gene expression, protein-protein interactions, signal transduction pathways, and monitoring of cells such as cancer cells, immune cells, and stem cells. In the near future, molecular imaging analysis will allow us to observe the incipience and progression of the disease. These will make us easier to give a diagnosis in the early stage of intractable diseases such as cancer, neuro-degenerative disease, and immunological disorders. Additionally, molecular imaging method will be a valuable tool for the real-time evaluation of cells in molecular biology and the basic biological studies. As newer and more powerful molecular imaging tools become available, it will be necessary to corporate clinicians, molecular biologists and biochemists for the planning, interpretation, and application of these techniques to their fullest potential. In order for such a multidisciplinary team to be effective, it is essential that a common understanding of basic biochemical and molecular biologic techniques is achieved. Basic molecular techniques for molecular imaging methods are presented in this paper.

Development of Dual Reporter System of Mutant Dopamine 2 Receptor (D2R) and Sodium Iodide Symporter (NIS) Transgenes / 대한핵의학회잡지

PURPOSE: Both human NIS and mutant D2R transgenes are proposed as reporting system in transplanted cell tracking. Using hepatoma cell lines, we constructed a dual reporter system containing human sodium-iodide symporter (hNIS) and dopamine 2 receptor (D2R) and compared its characteristics. MATERIALS AND METHODS: The recombinant plasmid (pIRES-hNIS/D2R) was constructed with IRES (internal ribosome entry site) under control of the CMV promoter. pIRES-hNIS/D2R was transfected to human hepatoma SK-Hep1 cell line with lipofectamine. HEP-ND (SK-Hep1-hNIS/D2R) cells stably expressing hNIS and D2R was established by selection with G418 for two weeks. RT-PCR was performed to investigate the expression of both hNIS and D2R genes. The expressions of hNIS and D2R were measured by 125I uptake assays and receptor binding assays. Specific binding of D2R to [3H]spiperone was verified by Scatchard plot with (+) butaclamol as a specific inhibitor. K (d) and B (max) values were estimated. The correlation between hNIS and D2R expression was compared by using each clone. RESULTS: Similar quantities of hNIS and D2R genes were expressed on HEP-ND as RT-PCR assays. HEP-ND cells showed 30 to 40 fold higher radioiodine uptakes than those of parental SK-Hep1 cells. 125I uptake in HEP-ND cells was completely inhibited by KClO4, a NIS inhibitor. Specific binding to HEP-ND cells was saturable and the K (d) and B (max) values for HEP-ND cells were 2.92 nM, 745.25 fmol/mg protein and 2.91nM, 1323 fmole/mg protein in two clones, respectively. The radioiodine uptake by hNIS activity and D2R binding was highly correlated. CONCLUSION: We developed a dual positron and gamma imaging reporter system of hNIS and D2R in a stably transfected cell line. We expect that D2R and hNIS genes can complement mutually as a nuclear reporting system or that D2R can be used as reporter gene when hNIS gene were used as a treatment gene.

A Study of Surface Physical Properties of New Surfactant Using Synthetic Peptides of Surfactant Protein-B

PURPOSE: To produce a new generation of artificial pulmonary surfactant(PS), surfactant protein (SP)-B from human PSwas isolated, and the amino acid sequences of these proteins were studied. Artificial peptides of human SP-B were synthesized. New artificial PS preparations which were cornposed of phospholopids and two artificial synthetic SP-B peptides were made, and the surface physical properties of these new PS preparations were tested. METHODS: The purities of SP-B were assessed by SDS-polyacrylamide gel and the amino acid sequences of these proteins were determined. We synthetized two peptides SP-1 and SP-2 and the amino acid sequences were as follows,' SP-1: RMLPQLVCRLVLRCSMD, SP-2: RMLP- QLVCRLVLRCSM. Surface physical properties of newly artificial PSs, which were composed of a mixture of phospholipid(PL) and SP-1 or SP-2(sample A; PL+SP-1, sample B; PL+SP-2), were measured by surface spreading, adsorption rate, and surface tension-area diagram. RESULTS: The amino acid sequence of human SP-B was obtained. We produced the artificial peptides of SP-B and prepared the new generation PS(sample A and sample B). The order of the superiority of spreading and adsorption rate was Surfacten

Comparison of in vitro Surface Physical Properties of Four Artificial Exogenous Pulmonary Surfactant Preparations

PURPOSE: We conducted this study to compare the surface physical properties of four commercial preparations of artificial exogenous pulmonary surfactants in vitro which have been used in both the prevention and treatment of respiratory distress syndrome in newborn infants. METHODS: We tested four surfactants : a) Surfacten (Tokyo Tanabe, Japan) and Newfactan (Yuhan, Korea) : reconstituted bovine lung extract, b) Curosurf (Cheisi, Italy) : porcine lung mince; chloroform-methanol extract; liquid-gel chromatography, and c) Exosurf (Wellcome, USA), synthetic surfactant composed of colfosceril, palmitate, hexadecanol, and tyloxapol. We measured the surface adsorption rate, spreading rate, and surface tension(ST)-area diagram by using modified Wilhelmy balance and minimum(min-ST) and maximum ST(max-ST) by Pulsating Bubble Surfactometer. RESULTS: The adsorption rate of Surfacten is less than 30mN/m and those of Newfactan, Curosurf, and Exosurf are more than 30mN/m. The spreading rate of Surfaten and Newfactan are less than 30mN/m, and those of Curosurf and Exosurf are more than 30mN/m. The min-ST of Surfacten and Newfacten are less than 10mN/m, and those of Curosurf and Exosurf are more than 10mN/m. According to high performance of surface physical activities, which are compared with in vitro criteria of effective artificial surfactant, they are as follows; Surfacten>Newfactan>Curosurf>Exosurf. CONCLUSION: There are some differences between the surface physical properties of the four surfactant preparations. The natural surfactants appear to be superior to synthetic surfactant in vitro. Among the natural surfactants, Surfacten showed the best surface physical activities of spreading, adsorption and ST-lowering properties.

Preparation and in vitro Physical Activities of Crude Natural Surfactant and Artificial Pulmonary Surfactant Containing Synthetic Peptide and Phospholipid Mixtures

PURPOSE: In this study, natural pulmonary surfactant was extracted from bovine lung lavage and its surface activity was determined. To investigate the usefulness of synthetic peptides reconstituted with phospholipid as artificial surfactant, truncated peptides from surfactant protein (SP)-B were synthesized and restored the surface tension lowering activities when appropriately recombined with phospholipid. METHODS: Crude natural surfactant (CNS) was isolated from lung lavage by centrifugation and organic solvent for the extraction of pulmonary surfactant was selected to satisfy the in vitro physical properties. Two truncated peptides derived from C-terminal end of bovine SP-B hydrophobic protein were selected and synthesized. To prepare artificial surfactant, synthetic peptides was added to the phospholipid mixture. The various surfactant mixtures were assayed for in vitro physical activity with the Wilhemly plate method and were determined by surface spreading rate, surface adsorption rate and surface tension-area diagram. RESULTS: CNS-chloroform methanol (CM) displayed efficient surface activity compared with clinically used Surfacten but CNS-BuOH did not. The artificial surfactants containing phospholipid mixture and synthetic peptide were analyzed for their surface activities and displayed significant surfactant properties. CONCLUSION: 1-Butanol or CM (3:1) was used as an extraction solvent for CNS. CNS-CM showed more efficient surface activity than CNS-BuOH. Two synthetic peptides composing artificial pulmonary surfactant were designed and mixing ratio of peptide and phospholipid was established. Artificial surfactant dispalyed weaker surface activity than natural surfactant but significant surfactant activity.

Cloning and Nucleotide Sequence Analysis of HLA - DRA * 0101 and DRB1 * 0405 Alleles / 대한면역학회지

No abstract available.