• Maxillofacial Plastic and Reconstructive Surgery
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• v.41
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• pp.25.1-25.5
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• 2019

Background: Brain abscess is a life-threatening condition that occurs due to complications during a neurosurgical procedure, direct cranial trauma, or the presence of local or distal infection. Infection in the oral cavity can also be considered a source of brain abscess. Case presentation: A 45-year-old male patient was transported with brain abscess in the subcortical white matter. Navigation-guided abscess aspiration and drainage was performed in the right mid-frontal lobe, but the symptoms continued to worsen after the procedure. A panoramic radiograph showed alveolar bone resorption around the maxillary molars. The compromised maxillary molars were extracted under local anesthesia, and antibiotics were applied based on findings from bacterial culture. A brain MRI confirmed that the three brain abscesses in the frontal lobe were reduced in size, and the patient's symptoms began to improve after the extractions. Conclusion: This is a rare case report about multiple uncontrolled brain abscesses treated by removal of infection through the extraction of maxillary molars with odontogenic infection. Untreated odontogenic infection can also be considered a cause of brain abscess. Therefore, it is necessary to recognize the possibility that untreated odontogenic infection can lead to serious systemic inflammatory diseases such as brain abscess. Through a multidisciplinary approach to diagnosis and treatment, physicians should be encouraged to consider odontogenic infections as a potential cause of brain abscesses.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.2
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• pp.174-178
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• 2006

Brain abscess is a rare, extremely aggressive, life-threatening infection. It may occur following : infection of contiguous structure, hematogenous spread, or cranial trauma/surgery. Dental pathology and/or treatment have been linked to a small number of brain abscesses as possible source of infection. 50-year-old male patient was presented with a brain abscess caused by Streptococcus viridans. In the case presented, the significant oral findings were chronic periapical and periodontal infection due to root remnant of lower right 3rd molar. A case history and brief literature review of brain abscess related odontogenic infection was presented after successful treatment with antibiotics and craniotomy.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.40 no.3
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• pp.147-151
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• 2014

In this report, we describe a case of brain abscess due to odontogenic infection. A 53-year-old female who had been suffering from headache and trismus for two weeks visited the Department of Oral and Maxillofacial Surgery at the Sun Dental Hospital (Daejeon, Korea). Even after several routine tests, we still could not make a diagnosis. However, after the combined multidisciplinary efforts of oral surgeons and neurosurgeons, the patient was treated for odontogenic infection and made an uneventful recovery. Therefore, patients with infections in the head and neck region showing symptoms such as headache, changes in mental state, nausea, vomiting, seizures, hemiplegia, speech disturbance, and visual disturbance, a brain abscess should be included in the list of differential diagnoses.

• Molecules and Cells
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• v.37 no.7
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• pp.518-525
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• 2014

Gammaherpesvirus (${\gamma}HV$) infection of the central nervous system (CNS) has been implicated in diverse neurological diseases, and murine ${\gamma}HV$-68 (MHV-68) is known to persist in the brain after cerebral infection. The underlying molecular mechanisms of persistency of virus in the brain are poorly understood. Here, we characterized a unique pattern of MHV-68 persistent infection in neuroblastoma cells. On infection with MHV-68, both murine and human neuroblastoma cells expressed viral lytic proteins and produced virions. However, the infected cells survived productive infection and could be cultured for multiple passages without affecting their cellular growth. Latent infection as well as productive replication was established in these prolonged cultures, and lytic replication was further increased by treatment with lytic inducers. Our results provide a novel system to study persistent infection of ${\gamma}HVs$ in vitro following de novo infection and suggest application of MHV-68 as a potential gene transfer vector to the brain.

• Journal of Veterinary Science
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• v.19 no.6
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• pp.750-758
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• 2018

Influenza virus infection is a zoonosis that has great socioeconomic effects worldwide. Influenza infection induces respiratory symptoms, while the influenza virus can infect brain and leave central nervous system sequelae. As children are more vulnerable to infection, they are at risk of long-term neurological effects once their brains are infected. We previously demonstrated that functional changes in hippocampal neurons were observed in mice recovered from neonatal influenza infection. In this study, we investigated changes in myelination properties that could affect neural dysfunction. Mice were infected with the influenza virus on postnatal day 5. Tissues were harvested from recovered mice 21-days post-infection. The expression levels for myelin basic protein (MBP) were determined, and immunohistochemical staining and transmission electron microscopy were performed. Real-time polymerase chain reaction and Western blot analyses showed that mRNA and protein expressions increased in the hippocampus and cerebellum of recovered mice. Increased MBP-staining signal was observed in the recovered mouse brain. By calculating the relative thickness of myelin sheath in relation to nerve fiber diameter (G-ratio) from electron photomicrographs, an increased G-ratio was observed in both the hippocampus and cerebellum of recovered mice. Influenza infection in oligodendrocyte-enriched primary brain cell cultures showed that proinflammatory cytokines may induce MBP upregulation. These results suggested that increased MBP expression could be a compensatory change related to hypomyelination, which may underlie neural dysfunction in recovered mice. In summary, the present results demonstrate that influenza infection during the neonatal period affects myelination and further induces functional changes in influenza-recovered mouse brain.

• Parasites, Hosts and Diseases
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• v.54 no.2
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• pp.201-204
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• 2016

Toxoplasma gondii is an intracellular protozoan that can modulate the environment of the infected host. An unfavorable environment modulated by T. gondii in the brain includes tumor microenvironment. Literature has suggested that T. gondii infection is associated with development of brain tumors. However, in Korea, epidemiological data regarding this correlation have been scarce. In this study, in order to investigate the relationship between T. gondii infection and brain tumor development, we investigated the seroprevalence of T. gondii among 93 confirmed brain tumor patients (various histological types, including meningioma and astrocytoma) in Korea using ELISA. The results revealed that T. gondii seropositivity among brain tumor patients (18.3%) was significantly (P<0.05) higher compared with that of healthy controls (8.6%). The seropositivity of brain tumor patients showed a significant age-tendency, i.e., higher in younger age group, compared with age-matched healthy controls (P<0.05). In conclusion, this study supports the close relationship between T. gondii infection and incidence of brain tumors.

• Journal of Trauma and Injury
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• v.35 no.4
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• pp.255-260
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• 2022

Purpose: To determine the incidence and risk factors of postoperative infection after cranioplasty in patients with traumatic brain injury (TBI). Methods: Data of 289 adult patients who underwent cranioplasty after TBI at a single regional trauma center between year 2018 and 2021 were reviewed retrospectively. Patient characteristics and various procedural variables, such as interval between craniectomy and cranioplasty, estimated blood loss, laterality and materials of the bone flap, and duration and classification of perioperative antibiotics usage were analyzed. Results: Postoperative infection occurred in 17 patients (5.9%). Onset time of infectious symptom ranged from 9 days to 174 days (median, 24 days) after cranioplasty. The most common cultured organism was Staphylococcus aureus (47.1%), followed by Klebsiella pneumoniae (17.6%) and Enterococcus faecalis (17.6%). Patients with postoperative infection were more likely to have diabetes (odds ratio [OR], 6.96; 95% confidence interval [CI], 1.92-25.21; P=0.003), lower body mass index (OR, 0.81; 95% CI, 0.66-0.98; P=0.029), and shorter duration of perioperative antibiotics (OR, 0.83; 95% CI, 0.71-0.98; P=0.026). Conclusions: For TBI patients with diabetes, poor nutritional status should be managed cautiously for increased risk of infection after cranioplasty. Further studies and discussions are needed to determine an appropriate antibiotics protocol in cranioplasty.

• IMMUNE NETWORK
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• v.23 no.5
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• pp.42.1-42.21
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• 2023

When the lungs are infected with bacteria, alveolar macrophages (AMs) are recruited to the site and play a crucial role in protecting the host by reducing excessive lung inflammation. However, the regulatory mechanisms that trigger the recruitment of AMs to lung alveoli during an infection are still not fully understood. In this study, we identified a critical role for NADPH oxidase 4 (NOX4) in the recruitment of AMs during Staphylococcus aureus lung infection. We found that NOX4 knockout (KO) mice showed decreased recruitment of AMs and increased lung neutrophils and injury in response to S. aureus infection compared to wildtype (WT) mice. Interestingly, the burden of S. aureus in the lungs was not different between NOX4 KO and WT mice. Furthermore, we observed that depletion of AMs in WT mice during S. aureus infection increased the number of neutrophils and lung injury to a similar level as that observed in NOX4 KO mice. Additionally, we found that expression of intercellular adhesion molecule-1 (ICAM1) in NOX4 KO mice-derived lung endothelial cells was lower than that in WT mice-derived endothelial cells. Therefore, we conclude that NOX4 plays a crucial role in inducing the recruitment of AMs by controlling ICAM1 expression in lung endothelial cells, which is responsible for resolving lung inflammation during acute S. aureus infection.

• Parasites, Hosts and Diseases
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• v.62 no.2
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• pp.243-250
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• 2024

We investigated organ specific Toxocara canis larval migration in mice infected with T. canis larvae. We observed the worm burden and systemic immune responses. Three groups of BALB/c mice (n=5 each) were orally administered 1,000 T. canis 2nd stage larvae to induce larva migrans. Mice were sacrificed at 1, 3, and 5 weeks post-infection. Liver, lung, brain, and eye tissues were collected. Tissue from 2 mice per group was digested for larval count, while the remaining 3 mice underwent histological analysis. Blood hematology and serology were evaluated and compared to that in a control uninfected group (n=5) to assess the immune response. Cytokine levels in bronchoalveolar lavage (BAL) fluid were also analyzed. We found that, 1 week post-infection, the mean parasite load in the liver (72±7.1), brain (31±4.2), lungs (20±5.7), and eyes (2±0) peaked and stayed constant until the 3 weeks. By 5-week post-infection, the worm burden in the liver and lungs significantly decreased to 10±4.2 and 9±5.7, respectively, while they remained relatively stable in the brain and eyes (18±4.2 and 1±0, respectively). Interestingly, ocular larvae resided in all retinal layers, without notable inflammation in outer retina. Mice infected with T. canis exhibited elevated levels of neutrophils, monocytes, eosinophils, and immunoglobulin E. At 5 weeks post-infection, interleukin (IL)-5 and IL-13 levels were elevated in BAL fluid. Whereas IL-4, IL-10, IL-17, and interferon-γ levels in BAL fluid were similar to that in controls. Our findings demonstrate that a small portion of T. canis larvae migrate to the eyes and brain within the first week of infection. Minimal tissue inflammation was observed, probably due to increase of anti-inflammatory cytokines. This study contributes to our understanding of the histological and immunological responses to T. canis infection in mice, which may have implications to further understand human toxocariasis.

• The Journal of the Korea Contents Association
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• v.12 no.9
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• pp.270-279
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• 2012

This paper explores CT findings of a rabbit brain infection model injected with Escherichia coli and investigates the changes in Hounsfield unit (HU) of arterial blood over time. The brain infection model was produced by injecting E. coli $1{\times}10^7$ CFU/ml, 0.1 ml through the burr hole in the calvarium; 2~3 mm in depth from the dura mater, and contrast-enhanced CT, dynamic CT and arterial blood CT images were gained. It was found that various brain infections such as brain abscess, ventriculitis and meningitis. The CT image of brain abscess showed a typical pattern which the peripheral area was strongly contrast-enhanced while the center was weakly contrast-enhanced. The CT image of ventriculitis showed a strong contrast-enhancement along the lateral ventricle wall, and the CT image of meningitis showed a strong contrast-enhancement in the area between the telencephalon and the diencephalon. In dynamic CT images, the HU value of the infection core before injecting contrast medium was $31.01{\pm}3.55$. By 10 minutes after the injection, the value increased gradually to $40.36{\pm}3.76$. The HU value in the areas of the marginal rim where was hyper-enhanced showed $47.23{\pm}3.12$ before contrast injection, and it increased to $63.59{\pm}3.31$ about 45 seconds after the injection. In addition, the HU value of the normal brain tissue opposite to the E. coli. injected brain was $39.01{\pm}3.24$ before the injection, but after the contrast injection, the value increased to $49.01{\pm}4.29$ in about 30 seconds, and then it showed a gradual decline. In the arterial blood CT, the HU value before the contrast injection was $87.78{\pm}6.88$, and it increased dramatically between 10 to 30 seconds until it reached a maximum value of $749.13{\pm}98.48$. Then it fell sharply to $467.85{\pm}62.98$ between 30 seconds to 45 seconds and reached a plateau by 60 seconds. Later, the value showed a steady decrease and indicated $188.28{\pm}25.03$ at 20 minutes. Through this experiment, it was demonstrated that the brain infection model can be produced by injecting E. coli., and the characteristic of the infection model can be well observed with contrast-enhanced CT scan. The dynamic CT scan showed that the center of the infection was gradually contrast-enhanced, whereases the peripheral area was rapidly contrast-enhanced and then slowly decreased. As for arterial blood, it increased significantly between 10 seconds to 30 seconds after the contrast medium injection and decreased gradually after reaching a plateau.