De novo assembled mitogenome analysis of Trichuris trichiura from Korean individuals using nanopore-based long-read sequencing technology.

Knowledge about mitogenomes has been proven to be essential in human parasite diagnostics and understanding of their diversity. However, the lack of substantial data for comparative analysis is still a challenge in Trichuris trichiura research. To provide high quality mitogenomes, we utilized long-read sequencing technology of Oxford Nanopore Technologies (ONT) to better resolve repetitive regions and to construct de novo mitogenome assembly minimizing reference biases. In this study, we got three de novo assembled mitogenomes of T. trichiura isolated from Korean individuals. These circular complete mitogenomes of T. trichiura are 14,508 bp, 14,441 bp, and 14,440 bp in length. A total of 37 predicted genes were identified consisting of 13 protein-coding genes (PCGs), 22 transfer RNA (tRNAs) genes, two ribosomal RNA (rRNA) genes (rrnS and rrnL), and two non-coding regions. Interestingly, the assembled mitogenome has up to six times longer AT-rich regions than previous reference sequences, thus proving the advantage of long-read sequencing in resolving unreported non-coding regions. Furthermore, variant detection and phylogenetic analysis using concatenated protein coding genes, cox1, rrnL, and nd1 genes confirmed the distinct molecular identity of this newly assembled mitogenome while at the same time showing high genetic relationship with sequences from China or Tanzania. Our study provided a new set of reference mitogenome with better contiguity and resolved repetitive regions that could be used for meaningful phylogenetic analysis to further understand disease transmission and parasite biology.

Subchondral stress fracture of the femoral head (SSFFH) in young and healthy military recruits: clinical recommendations and fracture configurations on MRI.

PURPOSE: This study aimed to evaluate the clinical and radiologic characteristics of the fatigue-type of SSFFH in healthy military recruits. MATERIALS AND METHOD: We retrospectively analyzed 39 hips from 32 patients who were treated for SSFFH between 2014 and 2018. Clinical variables were analyzed. We devised a categorization system that divided SSFFH into five types (A-E) according to the extent of the fracture line MRI axial view. The femoral head was divided into three parts for the categorization: the anterior third, middle third, and posterior third. RESULTS: The included patients were 39 hips from 32 patients with the mean age 22.3 years. Almost all patients with SSFFH (96.9%) complained of hip pain with limping at the time of diagnosis. The mean time to the onset of the hip pain from the beginning of military training was 24.8 days. There were seven patients (21.9%) with concomitant stress fractures on whole-body bone scan. Six hips (15.4%) developed osteoarthritis and required surgery. Almost all the cases (94.9%) involved the anterior compartment of the femoral head. CONCLUSIONS: Military recruits with the hip pain and limping within one month of military training should undergo detailed evaluation. A whole-body bone scan with SPECT is useful for identifying other concomitant stress fractures. Majority of SSFFH involved the anterior compartment of the femoral head.

Total Intravenous Anesthesia in a Malignant Hyperthermia-Susceptible Patient with Klinefelter Syndrome Undergoing Orthognathic Surgery.

ABSTRACT: A patient with Klinefelter syndrome and skeletal Class III malocclusion experienced a malignant hyperthermia-like reaction while undergoing orthognathic surgery. The patient fully recovered after prompt diagnosis and management, and surgery was reattempted under total intravenous anesthesia. The patient was discharged without any anesthetic complications and was satisfied with the surgical results. This is the first described case of a malignant hyperthermia-like event in a patient with Klinefelter syndrome. Total intravenous anesthesia may be safely administered in malignant hyperthermia-susceptible patients who require orthognathic surgery.

Multi-Layer Nanofibrous PCL Scaffold-Based Colon Cancer Cell Cultures to Mimic Hypoxic Tumor Microenvironment for Bioassay.

Three-dimensional (3D) cancer cell culture systems have been developed to aid the study of molecular mechanisms in cancer development, identify therapeutic targets, and test drug candidates. In this study, we developed a strategy for mimicking the hypoxic tumor microenvironment in a 3D cancer cell culture system using multi-layer, nanofibrous poly(ε-caprolactone) (PCL) scaffold (pNFS)-based cancer cell cultures. We found that human colon cancer cells infiltrated pNFS within 3 days and could be cultured three-dimensionally within the NFS. When incubated in four stacks of 30 µm-thick pNFS for 3 days, colon cancer cells in layer three showed partially reduced entry into the S phase, whereas those in layer four, located farthest from the media, showed a marked reduction in S-phase entry. As a consequence, cells in layer four exhibited hypoxia-induced disorganization of F-actin on day 3, and those in layers three and four showed an increase in the expression of the hypoxia-induced transcription factor HIF-1α and its target genes, Glut1, CA9, VEGF, and LDHA. Consistent with these results, doxorubicin- and ionizing radiation-induced cell death was reduced in colon cancer cells cultured in layers three and four. These results suggest that pNFS-based multi-layer colon cancer cell cultures mimic the hypoxic tumor microenvironment and are useful for bioassays.

Prevalence and Risk Factors of Intestinal Helminthiasis in Remote Mountainous Villages of Northern Lao PDR: A Cross-Sectional Study.

Helminth infections are prevalent in Lao People's Democratic Republic (Lao PDR). This study aimed at determining the prevalence and risk factors of intestinal helminthiasis in remote mountainous villages of northern Lao PDR. During the dry season in January 2017, a cross-sectional survey was conducted in 3 remote mountainous villages in Oudomxay province, Lao PDR. Villagers older than 18 years of age who agreed to submit stool samples or undergo an interview, were recruited. Stool samples from 198 individuals were examined by the Kato-Katz method, and a questionnaire surveyed 161 individuals among them. Univariable and multivariable logistic regression analyses were used to identify risk factors associated with the intestinal helminthiasis. An overall prevalence of intestinal helminthiasis was 75.8%. Hookworm infection was the most common (63.1%), followed by Opisthorchis viverrini/minute intestinal flukes (17.7%), Taenia spp. (15.2%), Trichuris trichiura (2.0%), Ascaris lumbricoides (1.5%), and Enterobius vermicularis (1.0%). Questionnaire analysis revealed sex (male) and absence of latrine to be significant risk factors for hookworm infection and consumption of raw meat for taeniasis. These results suggest that the mountainous area in northern Lao PDR has a different composition of helminth infections from other studies conducted in Lao PDR; a high prevalence of hookworm infection and taeniasis and low prevalence of T. trichiura and A. lumbricoides infections were observed. Also, liver flukes or intestinal flukes were similarly prevalent in the mountainous area.

Preemptive intravenous iron therapy versus autologous whole blood therapy for early postoperative hemoglobin level in patients undergoing bimaxillary orthognathic surgery: a prospective randomized noninferiority trial.

BACKGROUND: Previous studies have reported the efficacy and safety of intravenous (IV) iron therapy during the perioperative period as an alternative and adjunct to allogeneic blood transfusion. Preemptive IV iron therapy provides noninferior hemoglobin levels on postoperative day (POD) 1 compared to autologous whole blood therapy (AWBT) in healthy patients who had undergone bimaxillary orthognathic surgery. METHODS: This was a prospective, patient-randomized, noninferiority trial. After excluding 2 patients, 64 patients were divided into two groups: the IV iron therapy group (patients received IV iron infusion 4 weeks before surgery; n = 32) and the AWBT group (2 units of autologous whole blood were collected 4 and 2 weeks before surgery; n = 32). The primary outcome was hemoglobin level on POD 1 and the prespecified noninferiority limit was - 1 g/dL. RESULTS: Baseline data were comparable, including hemoglobin and iron levels, between the two groups. Immediately before surgery, the levels of hemoglobin, iron, and ferritin were higher in the IV iron group than in the AWBT group. The mean treatment difference (iron group-whole blood group) in hemoglobin level on POD 1 between the two groups was 0.09 (95% CI = - 0.83 to 1.0). As the lower limit of the 95% CI (- 0.83) was higher than the prespecified noninferiority margin (δ = - 1), noninferiority was established. On POD 2, the hemoglobin level became lower in the iron group, which eventually led to greater requirement of allogeneic blood transfusion compared to the whole blood group. However, the iron group did not require allogeneic blood transfusion during or early after surgery, and the whole blood group showed continuously higher incidence of overt iron deficiency compared to the iron group. CONCLUSION: As collection of autologous whole blood caused overt iron loss and anemia before surgery and intraoperative transfusion of whole blood was not able to prevent the occurrence of persistent iron deficiency after surgery, IV iron therapy was found to have potential benefits for iron homeostasis and subsequent erythropoiesis in healthy patients early after bimaxillary orthognathic surgery. TRIAL REGISTRATION: Clinical Research Information Service, Republic of Korea, approval number: KCT0003680 on March 27, 2019. https://cris.nih.go.kr/cris/search/search_result_st01_kren.jsp?seq=15769&sLeft=2<ype=my&rtype=my .

A first nation-wide assessment of soil-transmitted helminthiasis in Fijian primary schools, and factors associated with the infection, using a lymphatic filariasis transmission assessment survey as surveillance platform.

BACKGROUND: Soil-transmitted helminthiasis (STH) is endemic in Fiji but its prevalence is not known and likely to have changed after a decade of mass drug administration (MDA) for lymphatic filariasis (LF). By linking with LF transmission assessment surveys (LF-TAS), we undertook the first nation-wide assessment of STH in Fijian primary schools, as well as an analysis of factors associated with STH infections. METHODOLOGY/PRINCIPAL FINDINGS: A cross-sectional assessment for STH was conducted in all four Divisions of Fiji from 2014 to 2015. In the Western, Central, and Northern Divisions, schools were sub-sampled after LF-TAS, while, in the Eastern Division, schools were selected via simple random sampling. For the diagnosis of STH, stool samples were examined by coproscopy with a single Kato-Katz thick smear (KK) and the formol-ether-acetate concentration technique, except for the samples from the Eastern Division where only KK was used. Mean prevalence of any STH among class 1-2 students at the national level was 10.5% (95% CI: 6.9-15.5). Across the three Divisions via LF-TAS, the prevalence levels for ascariasis were 8.7% (95% CI: 4.3-16.6), hookworm 3.9% (95% CI: 2.3-6.6) and trichuriasis 0%. In the Eastern Division, ascariasis prevalence was 13.3% (95% CI: 6.4-25.6), and hookworm 0.7% (95% CI: 0.2-2.5), with one case of trichuriasis. Among class 3-8 students, ascariasis prevalence was lower. Lower risk of any STH was associated with wearing shoes (adjusted OR 0.54, 95% CI: 0.32-0.90) and having piped water from the Fiji Water Authority at home (adjusted OR 0.48, 95% CI: 0.25-0.92). CONCLUSIONS: After a decade of community-based LF-MDA, STH in school-age children in Fiji is now close to 10%, but localities of endemicity remain. Preventive chemotherapy should be maintained in areas with elevated STH prevalence alongside targeted delivery of integrated WASH interventions. LF-TAS has provided an opportunity to develop future public health surveillance platforms.

Cu(In,Ga)Se2 Solar Cells Integrated with Subwavelength Structured Cover Glass Fabricated by One-Step Self-Masked Etching.

We report an anti-reflective cover glass for Cu(In,Ga)Se2 (CIGS) thin film solar cells. Subwavelength structures (SWSs) were fabricated on top of a cover glass using one-step self-masked etching. The etching method resulted in dense whiskers with high aspect ratio. The produced structure exhibited excellent anti-reflective properties over a broad wavelength range, from the ultraviolet to the near infrared. Compared to a flat-surface glass, the average transmittance of the glass integrated with the SWSs improved from 92.4% to 95.2%. When the cover glass integrated with the SWSs was mounted onto the top of a CIGS device, the short-circuit current and the efficiency of the solar cell were enhanced by 4.38 and 6%, respectively, compared with a CIGS solar cell without cover glass.

Prevalence of Toxocariasis and Its Risk Factors in Patients with Eosinophilia in Korea.

Eosinophilia occurs commonly in many diseases including allergic diseases and helminthic infections. Toxocariasis has been suggested as one cause of eosinophilia. The present study was undertaken to examine the prevalence of toxocariasis in patients with eosinophilia and to identify the risk factors for toxocariasis. This prospective cohort study recruited a total of 81 patients with eosinophilia (34 males and 47 females) who visited the outpatient clinic at Seoul National University Hospital from January 2017 to February 2018 and agreed to participate in this study. The prevalence of toxocariasis was examined by T. canis-specific ELISA, and the various risk factors for toxocariasis were evaluated by a questionnaire survey. Among 81 patients with eosinophilia, 18 were positive for anti-T. canis antibodies (22.2%); 88.9% were male (16/18) and 11.1% were female (2/18). Multivariate statistical analysis revealed that males (OR 21.876, 95% CI: 1.667-287.144) with a history of consuming the raw meat or livers of animals (OR 5.899, 95% CI: 1.004-34.669) and a heavy alcohol-drinking habit (OR 8.767, 95% CI: 1.018-75.497) were at higher risk of toxocariasis in patients with eosinophilia. Toxocariasis should be considered a potential cause of eosinophilia when the patient has a history of eating the raw meat or livers of animals in Korea. A single course of albendazole is recommended to reduce the migration of Toxocara larvae in serologically positive cases with eosinophilia.

Co-Culturing of Endothelial and Cancer Cells in a Nanofibrous Scaffold-Based Two-Layer System.

Angiogenesis is critical for local tumor growth. This study aimed to develop a three-dimensional two-layer co-culture system to investigate effects of cancer cells on the growth of endothelial cells (ECs). Poly(ε-caprolactone) (PCL) nanofibrous membranes were generated via electrospinning of PCL in chloroform (C-PCL-M) and chloroform and dimethylformamide (C/DMF-PCL-M). We assembled a two-layer co-culture system using C-PCL-M and C/DMF-PCL-M for EC growth in the upper layer with co-cultured cancer cells in the lower layer. In the absence of vascular endothelial growth factor (VEGF), growth of bEND.3 ECs decreased on C/DMF-PCL-M but not on C-PCL-M with time. Growth of bEND.3 cells on C/DMF-PCL-M was enhanced through co-culturing of CT26 cancer cells and enhanced growth of bEND.3 cells was abrogated with anti-VEGF antibodies and sorafenib. However, EA.hy926 ECs displayed steady growth and proliferation on C/DMF-PCL-M, and their growth was not further increased through co-culturing of cancer cells. Moreover, chemical hypoxia in CT26 cancer cells upon treatment with CoCl2 enhanced the growth of co-cultured bEND.3 cells in the two-layer system. Thus, EC growth on the nanofibrous scaffold is dependent on the types of ECs and composition of nanofibers and this co-culture system can be used to analyze EC growth induced by cancer cells.

Case Report of Urinary Schistosomiasis in a Returned Traveler in Korea.

A 23-year-old Korean woman with a residence history in Kenya and Malawi for about 2 years presented with gross hematuria for 1 month. Blood tests were within normal range except eosinophilia. Asymmetrically diffuse wall thickening and calcification were observed at the urinary bladder on CT. Multiple erythematous nodular lesions were observed in the cystoscopy and transurethral resection was done. Numerous eggs of Schistosoma haematobium with granulomatous inflammation were observed in the submucosal layer of the bladder. The patient was diagnosed with schistosomiasis-related cystitis and treated with praziquantel (40 mg/kg/day) twice before and after transurethral resection. This case suggests that S. haematobium infection should be considered as a cause of hematuria in Korea when the patient had a history of traveling endemic areas of schistosomiasis.

An Imported Case of Disseminated Echinococcosis in Korea.

A complicated case of echinococcosis with multiple organ involvement is reported in a 53-year-old businessman who frequently traveled overseas, including China, Russia, and Kazakhstan from 2001 to 2007. The patient was first diagnosed with a large liver cyst during a screening abdomen ultrasonography in 2011, but he did not follow up on the lesion afterwards. Six years later, dizziness, dysarthria, and cough developed, and cystic lesions were found in the brain, liver and lungs. The clinical course was complicated when the patient went through multiple surgeries and inadequate treatment with a short duration of albendazole without a definite diagnosis. The patient visited our hospital for the first time in August 2018 due to worsening symptoms; he was finally diagnosed with echinococcosis using imaging and serologic criteria. He is now on prolonged albendazole treatment (400 mg twice a day) with gradual clinical and radiological improvement. A high index of suspicion is warranted to early diagnose echinococcosis in a patient with a travel history to endemic areas of echinococcosis.

Metformin Induces Apoptosis and Inhibits Proliferation through the AMP-Activated Protein Kinase and Insulin-like Growth Factor 1 Receptor Pathways in the Bile Duct Cancer Cells.

Background/Aims: Metformin has been found to have antineoplastic activity in some cancer cells. This study was performed to determine whether metformin inhibits the proliferation of bile duct cancer cells by inducing apoptosis and its effects on the expression of gene-related proteins involved in cancer growth. Methods: Human extrahepatic bile duct cancer cells (SNU-245 and SNU-1196) were cultured. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays were performed to determine the effect of metformin on the cell proliferation. Apoptosis was measured by a cell death detection enzyme-linked immunosorbent assay and a caspase-3 activity assay. Expression levels of various proteins, with or without specific small interfering ribonucleic acid-induced gene disruption, were measured by Western blot analysis. The migratory activity of the cancer cells was evaluated by wound healing assay. Results: Metformin suppressed cell proliferation in bile duct cancer cells by inducing apoptosis. Metformin inhibited mammalian target of rapamycin (mTOR) by activation of tuberous sclerosis complex 2 (TSC-2) through phosphorylation of adenosine monophosphate-activated protein kinase at threonine-172 (AMPKThr172). Hyperglycemia impaired metformin-induced AMPKThr172 activation and enhanced phosphorylation of AMPK at serine-485 (AMPKSer485). Metformin blocked the inhibitory effect of insulin-like growth factor 1 receptor (IGF-1R)/insulin receptor substrate 1 (IRS-1) pathway on TSC-2, and hyperglycemia impaired metformin-induced inhibition of IGF-1R/IRS-1 pathway and modulated the invasiveness of bile duct cancer cells; however, this effect was impaired by hyperglycemia. Conclusions: Metformin has antineoplastic effects in bile duct cancer, and hyperglycemic environment interrupts the effect of metformin. In addition, AMPK and IGF-1R play a key role in the proliferation of bile duct cancer cells.

Connexin 43 plays an important role in the transformation of cholangiocytes with Clonochis sinensis excretory-secretory protein and N-nitrosodimethylamine.

BACKGROUND: Clonorchis sinensis is a group I bio-carcinogen responsible for cholangiocarcinoma (CHCA) in humans. However, the mechanism by which C. sinensis promotes carcinogenesis is unclear. METHODOLOGY: Using the human cholangiocyte line H69, we investigated cell proliferation and gap junction protein expression after stimulation with the hepatotoxin N-nitrosodimethylamine (NDMA) and/or excretory-secretory products (ESP) of C. sinensis, which induce inflammation. NDMA and ESP treatment increased proliferation by 146% and the proportion of cells in the G2/M phase by 37%. Moreover, the expression of the cell proliferation-related proteins E2F1, Ki-67, and cancer related protein cytokeratin 19 and Cox-2 increased in response to combined treatment with NDMA and ESP. The gap-junction proteins connexin (Cx) 43 and Cx26 increased. In contrast, Cx32 expression decreased in cells treated with NDMA and ESP. Silencing of Cx43 reduced cell proliferation and significantly suppressed Cx26 and Cox-2 expression. CONCLUSIONS: These results suggest that Cx43 is an important factor in CHCA induced by C. sinensis ESP and NDMA and further investigations targeting this pathway may allow prevention of this deadly disease.

Effect of ilaprazole on the healing of endoscopic submucosal dissection-induced gastric ulcer: randomized-controlled, multicenter study.

BACKGROUND: The optimal treatment regimen or the duration of treatment for an endoscopic submucosal dissection (ESD)-induced gastric ulcer has not been established. The aim of this study was to assess the efficacy of novel proton-pump inhibitor, ilaprazole, for the treatment of ESD-induced gastric ulcer. METHODS: This was a prospective, open-label, randomized multicenter study. Between June 2015 and March 2018, a total of 176 patients (178 lesions) who underwent ESD for a gastric neoplasm were randomly allocated to receive the oral proton-pump inhibitor ilaprazole 20 mg or rabeprazole 20 mg daily for 8 weeks. The primary outcome was the ulcer healing rate at 4 and 8 weeks. RESULTS: A total of 155 (157 lesions) and 154 patients (156 lesions) were included in the modified intention-to-treat (mITT) and per-protocol analyses, respectively. There was no significant difference in the ulcer healing rate (ilaprazole vs. rabeprazole, 97.4% vs. 97.0 p = 0.78 at 4 weeks, 100% vs. 100%, p = 0.95 at 8 weeks in the mITT analysis) or stage of ulcer (scar stage, 25.6% vs. 17.7%, p = 0.25 at 4 weeks, 92.3% vs. 88.6%, p = 0.59 at 8 weeks in the mITT analysis) between the treatment groups. The quality of ulcer healing was not significantly different between the two groups. No independent predictive factor for higher-quality ulcer healing was found in the multivariate analysis. CONCLUSIONS: According to this trial, ilaprazole and rabeprazole showed no significant difference in the healing of artificial gastric ulcers. Most of the ulcers achieved complete healing within 4-8 weeks. TRIAL REGISTRATION: ClinicalTrial.gov NCT02638584.

Learning Curve for Lumbar Decompressive Laminectomy in Biportal Endoscopic Spinal Surgery Using the Cumulative Summation Test for Learning Curve.

OBJECTIVE: The purpose of the present study was to determine the learning curve for biportal endoscopic spinal surgery (BESS) for decompressive laminectomy in lumbar spinal stenosis using a learning curve cumulative summation test (LC-CUSUM). METHODS: The surgeon was proficient in open and microscopic decompressive laminectomy in lumbar spinal stenosis but did not have any experience with BESS or other endoscopic surgery techniques. The learning curve of BESS was investigated using LC-CUSUM analysis. Procedure success was defined as an operative time <75 minutes, the mean operative time with microscopic decompression laminectomy. RESULTS: The present study included the first 60 patients who had undergone single-level decompressive laminectomy using BESS by a single orthopedic surgeon. The mean operative time for decompressive laminectomy by BESS was 83.8 ± 37.9 minutes. The mean operative time in the early learning period (≤30 cases) and late learning period (second 30 cases) was 105.3 ± 39.7 minutes and 62.4 ± 19.9 minutes, respectively. The overall complication rate was ∼10%. The LC-CUSUM signaled competency for surgery at the 58th operation, indicating that sufficient evidence had accumulated to prove that the surgeon was competent. Thus, a trainee with no experience with BESS had reached adequate performance at 58 cases. CONCLUSIONS: The results of the present study have demonstrated that a substantial learning period could be needed before adequate performance can be achieved with lumbar decompressive laminectomy using BESS.

What Is Most Important to the Endoscopist for Therapeutic Plan? Morphology versus Pathology: A Nationwide Multicenter Retrospective Study in Korea.

Histologic discrepancy may sometimes occur between biopsy and endoscopic resection. We investigated the discrepancy rate between the biopsy and the resection lesion in the Korean population. From January 2010 to October 2016, 268 patients with gastric endoscopic mucosal resection/endoscopic submucosal dissection history from nationwide hospitals were enrolled retrospectively. We compared the histologic discrepancy rates from the biopsy and the resection. The mean age was 63.2 years. Gastric adenomas occurred most frequently in the antrum. The pathology of the resected specimens classified 25 lesions (9.3%) as gastritis/hyperplasia, 146 lesions (54.5%) as low-grade dysplasia, 76 lesions (28.4%) as high-grade dysplasia (HGD), and 21 lesions (7.8%) as adenocarcinoma. The discrepancy rate between biopsy and resection was 23.1 per cent. Among the 44 cases of gastritis/hyperplasia, two cases (4.5%) were diagnosed as HGD and 11 cases (25.0%) were diagnosed as cancer after resection. Among the 182 cases of low-grade dysplasia, 33 cases (18.1%) were diagnosed as HGD and nine cases (5.0%) were diagnosed as cancer after resection. Gastritis/hyperplasia, ulceration, and lesions in the lower body location were significant factors related to the discrepancies. Especially, discrepancy occurred most frequently in gastritis/hyperplasia lesions with ulcer in the lower body. There was considerable histologic discrepancy between biopsy and resection. Ulcerative-type tumor morphology and biopsy diagnosis of gastritis/hyperplasia are suggestive factors predictive of discrepancy between biopsy and resection in terms of malignancy. Therefore, although the results of biopsy are gastritis/hyperplasia, suspicious tumorous lesions with ulcer should be indicative of active endoscopic resection for diagnosis and treatment.

Investigation of tissue cysts in the retina in a mouse model of ocular toxoplasmosis: distribution and interaction with glial cells.

The conversion of tachyzoites into bradyzoites is a way for Toxoplasma gondii to establish a chronic and asymptomatic infection and achieve lifelong persistence in the host. The bradyzoites form tissue cysts in the retina, but not much is known about the horizontal distribution of the cysts or their interactions with glial cells in the retina. A chronic ocular toxoplasmosis model was induced by per oral administration of T. gondii Me49 strain cysts to BALB/c mice. Two months after the infection, retinas were flat-mounted and immunostained to detect cysts, ganglion cells, Müller cells, astrocytes, and microglial cells, followed by observation under fluorescence and confocal microscope. The horizontal distribution showed a rather clustered pattern, but the clusters were not restricted to certain location of the retina. Axial distribution was confined to the inner retina, mostly in ganglion cell layer or the inner plexiform layer. Both ganglion cells, a type of retinal neurons, and Müller cells, predominant retinal glial cells, could harbor cysts. The cysts were spatially separated from astrocytes, the most abundant glial cells in the ganglion cell layer, while close spatial distribution of microglial cells was observed in two thirds of retinal cysts. In this study, we demonstrated that the retinal cysts were not evenly distributed horizontally and were confined to the inner retina axially. Both neurons and one type of glial cells could harbor cysts, and topographic analysis of other glial cells suggests role of microglial cells in chronic ocular toxoplasmosis.

An Analysis of Infectious Disease Research Trends in Medical Journals From North Korea.

OBJECTIVES: This study aimed to investigate the current status of infectious disease research in North Korea by analyzing recent trends in medical journals from North Korea in comparison with research from South Korea. METHODS: Three medical journals (Preventive Medicine, Basic Medicine, and Chosun Medicine) were analyzed from 2012 to 2016. Articles on tuberculosis (TB), malaria, and parasitic diseases were selected and classified by their subtopics and study areas. Two medical journals published in the South Korea were selected for a comparative analysis of research trends. RESULTS: Of the 2792 articles that were reviewed, 93 were extracted from North Korea journals. TB research in North Korea was largely focused on multi-drug resistant TB and extrapulmonary TB, whereas research in South Korea more frequently investigated non-tuberculous mycobacteria. Research on parasitic diseases in North Korea was focused on protozoan and intestinal nematodes, while the corresponding South Korea research investigated various species of parasites. Additionally, the studies conducted in North Korea were more likely to investigate the application of traditional medicine to diagnosis and treatment than those conducted in South Korea. CONCLUSIONS: This study presents an analysis of research trends in preventive medicine in North Korea focusing on infectious diseases, in which clear differences were observed between South and North Korea. Trends in research topics suggest a high prevalence of certain parasitic diseases in North Korea that are no longer widespread in South Korea. The large proportion of studies examining traditional medicine implies a lack of affordable medicine in North Korea.