STATEMENT OF PROBLEM: There are many studies focused on the effect of shape of fixtures on stress distribution in the mandibular bone. However, there are no studies focused on the effect of the abutment types on stress distribution in mandibular bone. PURPOSE: The purpose of this study is to investigate the effect of three different abutment types on the stress distributions in the mandibular bone due to various loads by performing finite element analysis. Material and method : Three different implant systems produced by Warantec (Seoul, Korea) were modeled to study the effect of abutment types on the stress distribution in the mandibular bone. The three implant systems are classified into oneplant (Oneplant, OP-TH-S11.5), internal implant (Inplant, IO-S11.5) and external implant (Hexplant, EH-S11.5). All abutments were made of titanium grade ELI, and all fixtures were made of titanium grade IV. The mandibular bone used in this study is constituted of compact and spongeous bone assumed to be homogeneous, isotropic and linearly elastic. A comparative study of stress distributions in the mandibular bone with three different types of abutment was conducted. RESULTS: It was found that the types of abutments have significant influence on the stress distribution in the mandibular bone. It was due to difference in the load transfer mechanism and the size of contact area between abutment and fixture. Also the maximum effective stress in the mandibular bone was increased with the increase of inclination angle of load. CONCLUSION: It was concluded that the maximum effective stress in the bone by the internal implant was the lowest among the maximum effective stresses by other two types.
Finite Element Analysis ; Titanium

PURPOSES: The respiratory tract infection is one of the most prevalent and serious complications following hematopoietic stem cell transplantation (HSCT). Reports not only for the respiratory tract infection but, unlikely for bacteria or fungi, for the infections caused by the respiratory viruses have been rarely reported in Korea. During the winter of 2000~2001, authors wanted to know the prevalence rate of the respiratory tract infection and the kinds of causative microorganisms, especially the community respiratory viruses (CRV). Based on these data, we attempted to evaluate the clinical courses and prognosis of the patients. METHODS: From October 2000 to February 2001, specimens were collected from the patients who visited Catholic hemopoietic stem cell transplantation center, showing symptoms and signs of respiratory tract infection after HSCT. Standard methods have been applied to isolate and identify bacterial and fungal species. Measles was diagnosed based on the typical symptoms, rash, fever, and Koplik spot. For the four different CRV (adenovirus, RSV, influenza virus, parainfluenza virus), multiplex PCR and conventional culture method were used for the identification. RESULTS: Eighty-four specimens were collected from 66 patients for 4 month period. Average age of patients was 35+/-8 years. Sixty patients (90%) were received allogeneic HSCT. Sample collection was performed between 10 and 3,740 days (average 370 days, median 215 days) after HSCT. Forty-seven patients (71.2%) have been received immunosuppressants at the time of respiratory tract infection. Forty patients (60.6 %) were suffered lower respiratory tract infection and forty-four patients (66.7%) had community-acquired infection. Sixty microorganisms were identified from 45 patients out of total 66 patients. Identified microoganisms were bacteria accounting for 2 cases (3.4%), fungi for 11 (18.3%), tuberculosis for 5 (8.3%), and viruses for 42 (70.0%). Among viruses, 16 cases were measles (39%), 14 adenovirus (33%), 9 cytomegalovirus (21%), 2 parainfluenza virus (5%), 1 was influenza virus (2%). However, no RSV was identified. Most of patients showed good prognosis without any complications. Ten (15.2%) out of total 66 patients were expired. The direct cause of death for all 8 among 10 patients was pneumonia. CONCLUSION: Of the respiratory tract infection fol-lowing HSCT, most common causative microorganisms were viruses - measles, adenovirus in order. No case of RSV infection was found. No epidemic must be occurred by influenza virus because only 1 case was found. Fourteen patients were infected by more than one microorganisms. Overall mortality rate was 15.2%. This study is still undergoing and once accumulated data for more than 1 year, it might be possible to work out a strategies of treatment and prevention for respiratory tract infections. We also expect that these data might be able to provide the basis of efficient infection control in HSCT unit.
Adenoviridae ; Bacteria ; Bone Marrow Transplantation ; Cause of Death ; Community-Acquired Infections ; Cytomegalovirus ; Exanthema ; Fever ; Fungi ; Hematopoietic Stem Cell Transplantation* ; Hematopoietic Stem Cells* ; Humans ; Immunosuppressive Agents ; Infection Control ; Korea ; Measles ; Mortality ; Multiplex Polymerase Chain Reaction ; Orthomyxoviridae ; Paramyxoviridae Infections ; Pneumonia ; Prevalence ; Prognosis ; Respiratory System* ; Respiratory Tract Infections* ; Stem Cell Transplantation ; Tuberculosis

PURPOSE: Mesenchymal stem cells (MSCs) are surfacing as a new method of treatment for various diseases that have poor outcome with drug treatments. In this study, we investigated the effects of MSCs in a murine intestinal inflammation model mimicking human Crohn's disease (CD) using 2,4,5-trinitrobenzene sulfonic acid (TNBS). METHODS: Colitis was induced by rectal administration of 2 mg of TNBS in 35% ethanol as experimental group compared to control group. Histological changes, surface molecules of T and B cells of the spleen and blood, and cytokine production (IFN-gamma, TNF-alpha, IL-4, IL-6, IL-10, and IL-12) were determined among 3 groups comprised of control group, TNBS group and TNBS/MSC group. RESULTS: In the mice treated with MSCs, there was a decrease in the wasting disease process and inflammatory histopathological changes. There was also a decrease in pro-inflammatory T-helper 1 (Th1) cytokines IFN-gamma and IL-12 and T-helper 2 (Th2) cytokine IL-4. Anti-inflammatory cytokine IL-10 increased in mice treated with MSCs compared to colitic mice. The blood CD4+CD25+ T-regulatory cells also increased and splenic CD19 B-cells decreased. CONCLUSION: The results of this study suggest that MSCs may have a therapeutic effect in controlling the Th1 and Th2 mediated immune response in patients with CD and aid in tissue regeneration.
Administration, Rectal ; Animals ; B-Lymphocytes ; Colitis ; Crohn Disease ; Cytokines ; Ethanol ; Humans ; Inflammation ; Inflammatory Bowel Diseases ; Interleukin-10 ; Interleukin-12 ; Interleukin-4 ; Interleukin-6 ; Mesenchymal Stromal Cells ; Mice ; Regeneration ; Spleen ; Tumor Necrosis Factor-alpha ; Wasting Syndrome

Parkinson's disease (PD) is an irreversible neurological disorder with related locomotor dysfunction and is haracterized by the selective loss of nigral neurons. PD can be experimentally induced by 6-hydroxydopamine (6-OHDA). It has been reported that reactive oxygen species, which deplete endogenous glutathione (GSH) levels, may play important roles in the dopaminergic cell death characteristic of PD. Fucoidan, a sulfated algal polysaccharide, exhibits anti-inflammatory and anti-oxidant actions. In this study, we investigated whether fucoidan can protect against 6-OHDA-mediated cytotoxicity in SH-SY5Y cells. Cytotoxicity was evaluated by using MTT and LDH assays. Fucoidan alleviated cell damage evoked by 6-OHDA dose-dependently. Fucoidan reduced the number of apoptotic nuclei and the extent of annexin-V-associated apoptosis, as revealed by DAPI staining and flow cytometry. Elevation of lipid peroxidation and caspase-3/7 activities induced by 6-OHDA was attenuated by fucoidan, which also protected against cytotoxicity evoked by buthionine-sulfoximine-mediated GSH depletion. Reduction in the glutathione/glutathione disulfide ratio induced by 6-OHDA was reversed by fucoidan, which also inhibited 6-OHDA-induced disruption of mitochondrial membrane potential. The results indicate that fucoidan may have protective action against 6-OHDA-mediated neurotoxicity by modulating oxidative injury and apoptosis through GSH depletion.
Apoptosis ; Cell Death ; Flow Cytometry ; Glutathione ; Lipid Peroxidation ; Membrane Potential, Mitochondrial ; Nervous System Diseases ; Neurons ; Oxidopamine ; Parkinson Disease ; Reactive Oxygen Species

Two cases of human herpesvirus-6 (HHV-6) encephalitis that occurred after allogeneic hematopoietic stem cell transplant (HSCT) are presented. Both patients reported fever, skin rashes, and neurological symptoms, characterized by disorientation, confusion and drowsy mental status. HHV-6B DNA was detected from the cerebrospinal fluid (CSF) specimens by a multiplex polymerase chain reaction (PCR) assay including EBV, CMV, HHV-6B. After treatment with intravenous gan ciclovir for 2~3 weeks, all clinical manifestations were resolved and the HHV-6B DNA was cleared from the CSF in both patients. HHV-6 should be considered as a possible cause of neurological symptoms after HSCT, and prompt antiviral treatment should be begun.
Bone Marrow Transplantation ; Cerebrospinal Fluid ; DNA ; Encephalitis ; Exanthema ; Fever ; Hematopoietic Stem Cell Transplantation* ; Hematopoietic Stem Cells* ; Herpesvirus 4, Human ; Herpesvirus 6, Human ; Humans* ; Meningoencephalitis* ; Multiplex Polymerase Chain Reaction

Disseminated mucormycosis is a rare fungal infectious disease with a high mortality rate and is infrequently diagnosed ante mortem. It is most frequently seen in immunocompromised hosts such as diabetes mellitus, hematologic malignancies, or in the long-term use of steroids or chemotherapeutic agents. Tissue invasion by the hyphae of mucormycosis must be seen microscopically to establish the diagnosis. Treatment consists of correction of the predisposing condition, surgical debridement, and amphotericin-B therapy. A 35-year-old man was admitted through the emergency room due to fever and the right flank pain. He had received an allogenic bone marrow transplantation eight months ago and had been medicated with prednisolone and cyclosporine since the procedure. He was diagnosed with disseminated mucormycosis that involved the spleen, right kidney, and right lung. He is being successfully treated with amphotericin B, flucytosine, and liposomal amphotericin B.
Adult ; Amphotericin B ; Ants ; Bone Marrow Transplantation* ; Bone Marrow* ; Communicable Diseases ; Cyclosporine ; Debridement ; Diabetes Mellitus ; Diagnosis ; Emergency Service, Hospital ; Fever ; Flank Pain ; Flucytosine ; Hematologic Neoplasms ; Humans ; Hyphae ; Immunocompromised Host ; Kidney ; Lung ; Mortality ; Mucormycosis* ; Prednisolone ; Spleen ; Steroids

The target of rapamycin (TOR) signaling pathway is a conserved pathway that regulates eukaryotic cell growth in response to environmental cues. Chemical genomic approaches that profile rapamycin sensitivity of yeast deletion strains have given insights into the function of TOR signaling pathway. In the present study, we analyzed the rapamycin sensitivity of yeast deletion library strains on synthetic medium. As a result, we identified 130 strains that are hypersensitive or resistant to rapamycin compared with wild-type cells. Among them, 36 genes are newly identified to be related to rapamycin sensitivity. Moreover, we found 16 strains that show alteration in rapamycin sensitivity between complex and synthetic media. We suggest that these genes may be involved in part of TOR signaling activities that is differentially regulated by media composition.
Cues ; Eukaryotic Cells ; Saccharomyces ; Saccharomyces cerevisiae ; Sirolimus ; Yeasts

Invasive aspergillosis is the most common Aspergillus fumigatus infection in immunocompromised patients. Although the treatment of the invasive aspergillosis has been mostly relied on antifungal agents, there still exists the need for more effective therapy. To develop cellular immunotherapy specific for Aspergillus fumigatus, we generated specific T cells using dendritic cells (DCs) pulsed with an Aspergillus fumigatus derived recombinant protein in vitro and examined their functions. The f16. p2+3 region containing the conserved region of Asp f16 gene was cloned from Aspergillus fumigatus and the recombinant protein was produced in E. coli. IFN-gamma secretion from the T cells stimulated with recombinant f16. p2+3 (rf16. p2+3) was measured by enzyme linked immunospot (ELISPOT) assay and the cytolytic activity of the stimulated T cells by 51Cr release assay. The number of IFN-gamma secreting cells were significantly increased in the peripheral blood mononuclear cells (PBMCs) stimulated with the rf16. p2+3 pulsed DCs (31+/-12 spots/10(4) cells), compared to that of PBMCs directly stimulated with rf16. p2+3 (83+/-15 spots/10(6) cells). IFN-gamma ELISPOT assay using purified CD4+ or CD8+ as responder cells showed that CD4+ T cells (43 spots/10(4) cells) mainly produced IFN-gamma compared with CD8+ T cells (7 spots/10(4) cells). Furthermore, helper T cells specific for rf16. p2+3 could be efficiently generated by the stimulation with DCs for two weeks. However, cytotoxic T lymphocyte activity was not induced. Our results suggest that the rf16. p2+3 protein could be used for the generation of helper T cells in vitro.
Antifungal Agents ; Aspergillosis ; Aspergillus fumigatus* ; Aspergillus* ; Clone Cells ; Dendritic Cells* ; Enzyme-Linked Immunospot Assay ; Immunocompromised Host ; Immunotherapy ; Lymphocytes ; T-Lymphocytes* ; T-Lymphocytes, Helper-Inducer ; Viperidae*

The target of rapamycin (TOR) signaling pathway conserved from yeast to human plays critical roles in regulation of eukaryotic cell growth. It has been shown that TOR pathway is involved in several cellular processes, including ribosome biogenesis, nutrient response, autophagy and aging. However, due to the functional diversity of TOR pathway, we do not know yet some key effectors of the pathway. To find unknown effectors of TOR signaling pathway, we took advantage of a green fluorescent protein (GFP)-tagged collection of budding yeast Saccharomyces cerevisiae . We analyzed protein abundance changes by measuring the GFP fluorescence intensity of 4156 GFP-tagged yeast strains under inhibition of TOR pathway. Our proteomic analysis argues that 83 proteins are decreased whereas 32 proteins are increased by treatment of rapamycin, a specific inhibitor of TOR complex 1 (TORC1). We found that, among the 115 proteins that show significant changes in protein abundance under rapamycin treatment, 37 proteins also show expression changes in the mRNA levels by more than 2-fold under the same condition. We suggest that the 115 proteins indentified in this study may be directly or indirectly involved in TOR signaling and can serve as candidates for further investigation of the effectors of TOR pathway.
Aging ; Autophagy ; Eukaryotic Cells ; Fluorescence ; Humans ; Imidazoles ; Multiprotein Complexes ; Nitro Compounds ; Proteins ; Proteome ; Ribosomes ; RNA, Messenger ; Saccharomyces cerevisiae ; Saccharomycetales ; Sirolimus ; TOR Serine-Threonine Kinases ; Yeasts ; Organelle Biogenesis

We retrospectively reviewed the medical records of 284 patients with neutropenic fever following chemotherapy for acute leukemia at the Catholic Hematopoietic Stem Cell Transplantation Center from January 1998 to December 1999, to identify prognostic factors for infection related mortality. Twenty-eight patients died of infections. There was no difference in median age, gender ratio, or underlying disease between the dying and surviving groups. Bacteria were the main pathogens following chemotherapy, and Gram positive organisms predominated in the dying group. Pneumonia and sepsis were the main causes of death. There were 72 cases of invasive fungal infection and their mortality was 27.8%. Invasive fungal infection and previous history of fungal infection were independent prognostic factors for outcome. Recovery from neutropenia was the significant protective factor for mortality. In conclusion, the prognostic factors identified in this study could be useful for deciding on more intensive treatment for those patients at greater risk of death. To our knowledge, this is the first Korean study delineating prognostic factors in acute leukemic patients with infectious complications.
Adolescent ; Adult ; Aged ; Bacterial Infections/complications/*mortality ; Cause of Death ; Female ; Humans ; Korea ; Leukemia ; Leukemia, Lymphocytic, Acute/complications/*microbiology/*mortality ; Leukemia, Myelocytic, Acute/complications/*microbiology/*mortality ; Male ; Middle Aged ; Morbidity ; Multivariate Analysis ; Mycoses/complications/mortality ; Neutropenia ; Pneumonia/complications/mortality ; Prognosis ; Retrospective Studies ; Sepsis/complications/mortality ; Survival Rate