Comparison of chronic gastrointestinal and genitourinary toxicities between brachytherapy and external beam radiotherapy for patients with prostate cancer: A systematic review and meta-analysis.

BACKGROUND: 125I BT is an effective radiotherapy for prostate cancer. However, comparison data of GI and GU toxicities between BT, BT + EBRT, and EBRT-alone patient groups is limited. OBJECTIVE: To define the GI and GU toxicities in prostate cancer to prevent adverse events after treatment. METHODS: We searched published studies in PubMed, Cochrane, and Embase databases up to December 31, 2022. The endpoints were the RRs of GI and GU toxicities. Pooled data were assessed using a random-effects model. RESULTS: Fifteen eligible studies were included into this analysis. LDR-BT had significantly lower RRs than LDR-BT + EBRT for acute GI (2.13; 95% CI, 1.22-3.69; P= 0.007) and late GI toxicities (3.96; 95% CI, 1.23-12.70; P= 0.02). Moreover, EBRT had significantly higher RRs than LDR-BT for acute GU (2.32; 95% CI, 1.29-4.15; P= 0.005) and late GU toxicities (2.38; 95% CI, 1.27-4.44; P= 0.007). HDR-BT had significantly higher RRs for acute GU toxicities than LDR-BT alone (0.30; 95% CI, 0.23-0.40; P< 0.00001). CONCLUSION: The results implied that BT with and without EBRT can result in both GI and GU toxicities in patients with prostate cancer, with LDR-BT leading to a poorer urinary function than EBRT.

Role of IL-17 family cytokines in the progression of IPF from inflammation to fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a fatal chronic interstitial lung disease with no established treatment and is characterized by progressive scarring of the lung tissue and an irreversible decline in lung function. Chronic inflammation has been demonstrated to be the pathological basis of fibrosis. Emerging studies have revealed that most interleukin-17 (IL-17) isoforms are essential for the mediation of acute and chronic inflammation via innate and adaptive immunity. Overexpression or aberrant expression of IL-17 cytokines contributes to various pathological outcomes, including the initiation and exacerbation of IPF. Here, we aim to provide an overview of IL-17 family members in the pathogenesis of IPF.

Combined Application of Quantitative Susceptibility Mapping and Diffusion Kurtosis Imaging Techniques to Investigate the Effect of Iron Deposition on Microstructural Changes in the Brain in Parkinson's Disease.

Objectives: Brain iron deposition and microstructural changes in brain tissue are associated with Parkinson's disease (PD). However, the correlation between these factors in Parkinson's disease has been little studied. This study aimed to use quantitative susceptibility mapping combined with diffusion kurtosis imaging to investigate the effects of iron deposition on microstructural tissue alterations in the brain. Methods: Quantitative susceptibility mapping and diffusion kurtosis imaging were performed on 24 patients with early PD, 13 patients with advanced PD, and 25 healthy controls. The mean values of magnetic susceptibility and diffusion kurtosis were calculated for the bilateral substantia nigra, red nucleus, putamen, globus pallidus, and caudate nucleus, and compared between the groups. Correlation analyses between the diffusion kurtosis of each nucleus and its magnetic susceptibility parameters in PD patients and healthy controls were performed. Results: The study found a significant increase in iron deposition in the substantia nigra, red nucleus, putamen and globus pallidus, bilaterally, in patients with PD. Mean kurtosis values were increased in the substantia nigra but decreased in the globus pallidus; axial kurtosis values were decreased in both the substantia nigra and red nucleus; radial kurtosis values were increased in the substantia nigra but showed an opposite trend in the globus pallidus and caudate nucleus. In the substantia nigra of patients with PD, magnetic susceptibility was positively correlated with mean and radial kurtosis values, and negatively correlated with axial kurtosis. None of these correlations were significantly different in the control group. In the putamen, magnetic susceptibility was positively correlated with mean, axial, and radial kurtosis only in patients with advanced-stage PD. Conclusion: Our study provides new evidence for brain iron content and microstructural alterations in patients with PD. Iron deposition may be a common mechanism for microstructural alterations in the substantia nigra and putamen of patients with PD. Tracking the dynamic changes in iron content and microstructure throughout the course of PD will help us to better understand the dynamics of iron metabolism and microstructural alterations in the pathogenesis of PD and to develop new approaches to monitor and treat PD.

A case report of serpentine-like syndrome and review of literature.

BACKGROUND: Serpentine-like syndrome (SLS) is a rare foetal abnormality, characterized by brachioesophagus, secondary intrathoracic stomach and vertebral deformity. Herein, we report a case of SLS diagnosed based on imaging, genetic examination and autopsy findings. CASE PRESENTATION: From the 19th to 23rd weeks of gestation, the foetus presented with brachioesophagus, secondary intrathoracic stomach, intrathoracic spleen with poly-spleen malformation, spinal deformity and diaphragm dysplasia, and some abdominal organs were partly located in the thoracic cavity. After extensive counselling, the couple opted to terminate the pregnancy. Whole genome sequencing and autopsy were performed. Then, the foetus was diagnosed with SLS. DISCUSSION AND CONCLUSIONS: SLS is characterized by multiorgan deformities and is associated with poor prognosis. Multiorgan deformities can be detected on prenatal sonography using three-dimensional ultrasound technology.

Clinical value and application of preoperative CT-guided hookwire localization of solitary pulmonary nodules for video-assisted thoracic surgery.

BACKGROUND: Video-assisted thoracic surgery (VATS) is a minimally invasive technique for the diagnosis and management of small pulmonary nodular lesions However, the identification of some lung nodules remains difficult. OBJECTIVE: This research aimed to investigate the clinical value of preoperative computed tomography (CT)-guided hookwire localization of solitary pulmonary nodules (SPNs) for thoracoscopic resection. METHODS: Seventy-one patients with 74 SPNs underwent VATS wedge resection after CT-guided hookwire localization. The mean diameter of the SPNs was 8.50 ± 4.53 mm,,besides, the mean distance from the SPNs to the parietal pleura was 16.81 ± 5.23 mm. RESULTS: Sixty-nine of the 74 nodules were successfully localized using a CT-guided hookwire. The success rate of CT-guided localization was 93.2%. The average localization time was 15.23 ± 7.21 min per lesion. Seven patients (9.5%) had asymptomatic pneumothorax and 10 (13.5%) had minimal needle tract parenchymal hemorrhages after localization no clinical intervention was required for these patients. The rate of success for VATS wedge resection of the SPNs was 100%. Histological analysis of the SPNs revealed malignant disease in 67.4% of the patients. CONCLUSIONS: Preoperative CT-guided hookwire localization for thoracoscopic resection is a safe and effective operation for the identification and stable fixation of SPNs.

Crown-Rump Length Discordance, Increased Nuchal Translucency, and Detection of Fetal Structural Anomalies in Twin Pregnancies in the First Trimester: 5 Years of Experience in a Tertiary Hospital in China.

OBJECTIVE: To evaluate the efficacy of the first-trimester ultrasound scan in the detection of fetal structural anomalies in twin pregnancies. To examine the association between increased nuchal translucency (NT) thickness, crown-rump length (CRL) or NT discordance, and detection of structural anomalies in a large twin series in China. METHODS: We performed retrospective analysis of twin pregnancies who underwent 11-13+6 -week and second-trimester anomaly scan and booked at Beijing Obstetrics and Gynecology Hospital between January 2012 and December 2016. Measurement of fetal CRL/NT and assessment of fetal anatomic structures were based on standard (not detailed) protocols. Conjoined twins and twin-reversed arterial perfusion sequence (TRAPS) were excluded from structural anomalies. The diagnostic performance of first-trimester ultrasound in detection of fetal structural anomalies in twins was determined and compared with that of second trimester. The accuracy of independent variates associated with structural anomaly detection was calculated. RESULTS: A total of 1442 women with twin pregnancies were included. In 40 women and 45 fetuses, structural anomalies were found. Fetal structural anomalies verified at delivery were detected in 42.5% (17/40) of affected pregnancies in the first trimester and 92.5% (37/40) of affected pregnancies when added second trimester (P = .13). The survival rate of pregnancies detected in second trimester was higher than that of pregnancies detected in first trimester (11.8% vs 65.2%). The mean value of intertwin CRL/NT discordance in cases with fetal structural anomalies was larger in monochorionic twins than dichorionic twins, but monochorionicity was not associated with structural anomalies. CRL discordance ≥10% (OR 3.1, 95%CI 1.5-6.3) and NT ≥95th centile (OR 20.0, 95%CI 9.0-44.2) were associated with fetal structural anomalies. In both dichorionic (DC) and monochorionic (MC) twins, the percentages of CRL discordance ≥10% was larger in twins with structural anomalies than those without structural anomalies (37.5% vs 13.4% in DC twins and 50.0% vs 12.5% in MC twins), and this was also true for NT ≥95th centile (31.3% vs 1.7% in DC twins and 37.5% vs 2.2% in MC twins). In the setting of CRL discordance ≥10%, 40.0% (16/40) of twins with structural anomalies were found, in which the predominant fetal structural anomalies were cardiovascular defects, abdominal wall defects, and central nervous system defects. The AUC for detecting structural anomalies by CRL discordance ≥10% was 0.63. In the setting of NT ≥95th centile, 32.5% (13/40) of twins with structural anomalies were found, in which the predominant fetal structural anomalies were cardiovascular defects, cystic hygroma, and abdominal wall defects. The AUC for detecting structural anomalies by NT ≥95th centile was 0.65. CONCLUSIONS: The detection rate of twins with fetal structural anomalies was 42.5% per pregnancy in the first trimester. CRL discordance ≥10% and NT ≥95th centile may indicate higher risk of fetal structural anomalies in twins, but their efficacy was limited.

Quantitative metabolic characteristics in the peritumoral region of gliomas at 7T.

BACKGROUND: The determination of tumor peripheral is of great significance in clinical diagnosis and treatment. OBJECTIVE: In this study, we aim to obtain the metabolic condition in tumor peripheral of gliomas in vivo at 7T. METHODS: C6 glioma cells were implanted into the right basal ganglia of Sprague-Dawley (SD) rats under stereotactic guided to create the glioma models. The models were sequentially undergone MRI and MRS examination on an 7T MR scanner designed for animals 7 days after the operation. Neuro metabolites were investigated from the center of the tumor, solid part of the tumor, peritumoral region, and contralateral white matter, and be quantified using the LCmodel software. Glial fibrillary acidic protein (GFAP) immunohistochemistry and conventional hematoxylin and eosin (HE) staining were performed after the imaging protocol. RESULTS: Our results found that the inositol (Ins) and taurine (Tau) significantly defected in tumor peripheral compared to both tumor solid and normal tissues (P< 0.05). In contrast, the glutamate and glutamine (Glx) escalated and peaked at the tumor peripheral (P< 0.05). CONCLUSIONS: This study revealed that Ins, Tau, and Glx have the potential to provide specific biomarkers for the location of tumor peripheral of glioma.

Magnetic resonance imaging features of fibromas and giant cell tumors of the tendon sheath: differential diagnosis.

PURPOSE: The clinical and imaging characteristics of fibromas of the tendon sheath (FTS) closely resemble those of giant cell tumors of the tendon sheath (GCTTS). We aimed to study MRI features of FTS and GCTTS to distinguish the two entities and improve their differential diagnosis. MATERIALS AND METHODS: We retrospectively analyzed data from 18 patients (9 men, 9 women; age, 17-62 years) and 24 patients (13 men, 11 women; age, 15-67 years) treated between May 2011 and May 2016, with histologically confirmed FTS and GCTTS, respectively. Specific MRI features of the two groups were compared using the independent sample t tests and chi-square tests. RESULTS: FTS exhibited round or oval shapes. Proton-weighted images (PDWI) showed heterogeneous hypointensity that appeared striped or disordered and was located in the lesion center. Enhanced scans demonstrated asymmetrical signal in the foci. GCTTS mostly exhibited a lobulated or casting mold pattern, with a hypointense ring on PDWI. The hypointense components appeared granular/flaky or separated, sometimes behaving as a uniform signal on PDWI. Significant differences in the following features were observed between the two groups: lesion morphology (p < 0.001); imaging features on PDWI, including whether the signal is homogeneous (p < 0.001); the presence of a hypointense ring (p = 0.006); the location and morphology of hypointensity (p < 0.001); bone absorption (p = 0.008); enhancing pattern (p = 0.008); and whether the tumor crossed the joint (p = 0.026). CONCLUSIONS: FTS and GCTTS demonstrate distinctive MRI features, which can be used for differential diagnosis with sensitivities, specificities, and diagnostic accuracies of 83-100%, 29-79%, and 60-89%, respectively. KEY POINTS: • Fibromas and giant cell tumors of the tendon sheath have distinct features on MRI, including differences in lesion morphology and intensity patterns, which can be used for differential diagnosis. • Among other signs, GCTTS are more uniform than FTS, and FTS have a striped or disordered pattern. • Tumors were classified with 90% accuracy into either FTS or GCTTS based on a combination of two features: homogenous signal and hypointensity shape on PDWI.

Comparison of relative and absolute values of magnetic resonance imaging in the diagnosis of spinal epidural lipomatosis.

OBJECTIVE: To describe spinal epidural lipomatosis (SEL) of the lumbar region and evaluate the relative versus absolute values of epidural fat (EF) to determine which is more appropriate when using magnetic resonance imaging (MRI). DESIGN: Comparative study. SETTING: Hospital. PARTICIPANTS: Eight SEL patients and 40 healthy adults. INTERVENTIONS: MRI measurement of EF. OUTCOME MEASURES: The MRI-based EF thickness, cutoff value, and coefficient of variation (CV) were calculated. Frequency distribution maps for the absolute EF value and the relative EF/DuS value were created. RESULTS: SEL involved L3 - L4 in all cases. The mean EF thickness was 12.11 ± 2.28 mm (range: 9.91 - 16.86 mm), and the average diameter of the dural sac (DuS) was 20.02 ± 2.64 mm; the EF/DuS ratio was 0.61 ± 0.03. In controls, the average EF thickness was 7.35 ± 1.68 mm (range: 4.81 - 10.92 mm), and the average DuS was 20.86 ± 2.11 mm; the EF/DuS ratio was 0.35 ± 0.08. The relative and absolute values were significantly higher in the SEL group than in the normal group. A cutoff value of 9.8 mm could distinguish SEL patients from normal individuals. For the SEL group, the CV of the relative values (4.9%) was lower than that of the absolute values (18.8%). The frequency distribution map showed that the distribution of relative values was more concentrated than that of the absolute values for both groups. CONCLUSION: Based on the frequency distribution and CVs, the relative value of EF/DuS maybe a better measure for diagnosing SEL than the absolute EF value.

An application study of low-dose computed tomography perfusion imaging for evaluation of the efficacy of neoadjuvant chemotherapy for advanced gastric adenocarcinoma.

BACKGROUND: This study used low-dose computed tomography (CT) perfusion imaging technology to evaluate the efficacy of neoadjuvant chemotherapy in patients with advanced gastric adenocarcinoma and to determine whether any of the perfusion parameters could predict tumor response to chemotherapy. METHODS: Forty patients with gastric adenocarcinoma (T3-4NxM0) received three cycles of neoadjuvant chemotherapy and low-dose spiral CT perfusion imaging prior to and after the first and third series of chemotherapy. We calculated tissue blood flow (BF) and blood volume (BV) using commercial software. One-way analysis of variance (ANOVA) was used to detect any significant variation of the tested parameters between different times of scanning. Spearman's test was used to evaluate the correlation among perfusion parameters, tumor size and pathological efficacy grade, and clinical response after chemotherapy, respectively. A receiver-operating characteristic analysis was used to determine the optimal diagnostic cutoff value for changes in perfusion parameters and tumor size. RESULTS: One-way ANOVA showed significant differences in BF and BV values between those before and after chemotherapy (p < 0.01). The BF, BV and size reduction rate after three series of chemotherapy were significantly correlated with pathological efficacy grade. BF and BV values after the first and third series of chemotherapy were also significantly correlated with clinical response (p < 0.01, respectively). The diagnostic sensitivity and specificity of the BV reduction rate were higher than those of size reduction rate. CONCLUSIONS: Low-dose CT perfusion imaging is a valuable tool that permits microcirculation evaluation and therefore can evaluate the efficacy of neoadjuvant chemotherapy in patients with advanced gastric adenocarcinoma.

Identification and Genotypic Characterization of Potentially Pathogenic Acanthamoeba Isolated from Tap Water in Wuxi, China.

Members of genus Acanthamoeba are widely distributed in the environment. Some are pathogenic and cause keratitis and fatal granulomatous amoebic encephalitis. In this study, we isolated an Acanthamoeba CJW/W1 strain from tap water in Wuxi, Jiangsu Province, China. Its 18S rDNA was sequenced and a phylogenetic tree was constructed. The isolated cysts belonged to morphologic group II. Comparison of 18S rDNA sequences of CJW/W1 strain and other isolates showed high similarity (99.7%) to a clinical isolate Asp, KA/E28. A phylogeny analysis confirmed this isolate belonged to the pathogenic genotype T4, the most common strain associated with Acanthamoeba-related diseases. This is the first report of an Acanthamoeba strain isolated from tap water in Wuxi, China. Acanthamoeba could be a public health threat to the contact lens wearers and, therefore, its prevalence should be monitored.

Role of CT perfusion imaging in patients with variously differentiated gastric adenocarcinoma.

PURPOSE: To explore the characteristics of variously differentiated gastric cancers on computed tomography (CT) perfusion imaging, including specific perfusion parameter values, and potential clinical applications in the prognosis assessment of gastric cancer. MATERIALS AND METHODS: Fifty patients with gastric cancer confirmed by gastroscope pathology were studied prospectively using CT perfusion imaging examinations on a 64-slice spiral CT scanner. The acquired volume data were used for calculations, mapping, and analysis by using an abdominal tumor perfusion protocol (deconvolution method) in the CT perfusion software package to measure 4 parameters: blood flow (BF), blood volume (BV), mean transit time (MTT), and the permeability surface (PS) area product. The different differentiated Gastric cancers with CT perfusion values were divided into 3 groups: well-differentiated, moderately differentiated and poorly differentiated gastric adenocarcinoma, and compared statistically with one another by statistical software. RESULTS: The mean perfusion values of 10 patients with well-differentiated gastric adenocarcinoma were as follows: BF, 75.28 ± 6.81 mL/100 g/min; BV, 9.01 ± 0.94 mL/100 g; MTT, 9.89 ± 1.65 s; and PS, 10.05 ± 0.71 mL/100 g/min. The mean perfusion values of 24 patients with moderately differentiated gastric adenocarcinoma were as follows: BF, 110.01 ± 31.90 mL/100 g/min; BV, 18.18 ± 5.62 mL/100 g; MTT, 9.81 ± 3.69 s; and PS, 40.08 ± 15.82 mL/100 g/min. The mean perfusion values of 16 patients with poorly differentiated gastric adenocarcinoma were as follows: BF, 138.59 ± 38.09 mL/100 g/min; BV, 21.08 ± 4.11 mL/100 g; MTT, 9.47 ± 1.80 s; and PS, 57.50 ± 13.28 mL/100 g/min. Comparing the 3 groups, differences between the well-differentiated group and the moderate differentiation group were all statistically significant for BF, BV, and PS (p < 0.05, respectively), differences between the well-differentiated group and the poor differentiation group were all statistically significant for BF, BV, and PS (p < 0.05,respectively) as well; While MTT value showed no statistical difference among the 3 groups (p > 0.05). CONCLUSION: Stomach CT perfusion imaging is a functional imaging technology from the perspective of hemodynamics with potential clinical applications. The BF, BV and PS values could serve as indicators of the degree of malignancy and aid in prognostic assessment of gastric cancer.

Microarray and KOG analysis of Acanthamoeba healyi genes up-regulated by mouse-brain passage.

Long-term cultivation in a laboratory could reduce the virulence of Acanthamoeba. To identify virulence factors of Acanthamoeba, the authors compared the transcription profiles of long-term cultivated Acanthamoeba healyi (OLD) and three times mouse-brain passaged A. healyi (MBP) using microarray analysis and eukaryotic orthologous group (KOG) assignments. Microarray analysis revealed that 601 genes were up-regulated by mouse-brain passage. The results of real-time PCR of 8 randomly selected genes up-regulated in the MBP strain confirmed microarray analysis findings. KOG assignments showed relatively higher percentages of the MBP strain up-regulated genes in T article (signal transduction mechanism), O article (posttranslational modification, protein turnover, chaperones), C article (energy production and conversion), and J article (translation, ribosomal structure and biogenesis). In particular, the MBP strain showed higher expressions of cysteine protease and metalloprotease. A comparison of KOG assignments by microarray analysis and previous EST (expressed sequence tags) analysis showed similar populations of up-regulated genes. These results provide important information regarding the identification of virulence factors of pathogenic Acanthamoeba.

Microarray analysis of differentially expressed genes between cysts and trophozoites of Acanthamoeba castellanii.

Acanthamoeba infection is difficult to treat because of the resistance property of Acanthamoeba cyst against the host immune system, diverse antibiotics, and therapeutic agents. To identify encystation mediating factors of Acanthamoeba, we compared the transcription profile between cysts and trophozoites using microarray analysis. The DNA chip was composed of 12,544 genes based on expressed sequence tag (EST) from an Acanthamoeba ESTs database (DB) constructed in our laboratory, genetic information of Acanthamoeba from TBest DB, and all of Acanthamoeba related genes registered in the NCBI. Microarray analysis indicated that 701 genes showed higher expression than 2 folds in cysts than in trophozoites, and 859 genes were less expressed in cysts than in trophozoites. The results of real-time PCR analysis of randomly selected 9 genes of which expression was increased during cyst formation were coincided well with the microarray results. Eukaryotic orthologous groups (KOG) analysis showed an increment in T article (signal transduction mechanisms) and O article (posttranslational modification, protein turnover, and chaperones) whereas significant decrement of C article (energy production and conversion) during cyst formation. Especially, cystein proteinases showed high expression changes (282 folds) with significant increases in real-time PCR, suggesting a pivotal role of this proteinase in the cyst formation of Acanthamoeba. The present study provides important clues for the identification and characterization of encystation mediating factors of Acanthamoeba.

Acanthamoeba healyi: expressed gene profiles with enhanced virulence after mouse-brain passage.

The virulence of Acanthamoeba can be attenuated by long-term in vitro cultivation, and can be recovered by serial mouse-brain passage via intranasal inoculation. Recovery is concomitant with changes in expression of virulence-related genes. To investigate the virulence factors of Acanthamoeba, expressed sequence tags (ESTs) from two kinds of cDNA libraries-long-term in vitro cultivated A. healyi (OLD) and three times mouse-brain passaged A. healyi (MBP)-were compared using reciprocal BLAST analysis, eukaryotic orthologous groups (KOG) assignment, and gene annotation. A total of 938 (OLD) and 1033 (MBP) ESTs were sequenced and resulted in the assembling of 718 OLD and 833 MBP unique sequences. Comparison of the KOG analysis revealed a relatively higher percentage of MBP ESTs in genes related to transcription (K group), amino acid transport and metabolism (E group), coenzyme transport and metabolism (H group), and secondary metabolites biosynthesis, transport and metabolism (Q group). However, a higher percentage of unidentified MBP ESTs (57.9%) than OLD ESTs (28.9%) was evidence of the limited understanding of virulence-related factors of Acanthamoeba. Characterization of the genes expressed during brain passage in mice will be useful in clarifying the pathogenesis of granulomatous amoebic encephalitis by Acanthamoeba.

Construction of EST database for comparative gene studies of Acanthamoeba.

The genus Acanthamoeba can cause severe infections such as granulomatous amebic encephalitis and amebic keratitis in humans. However, little genomic information of Acanthamoeba has been reported. Here, we constructed Acanthamoeba expressed sequence tags (EST) database (Acanthamoeba EST DB) derived from our 4 kinds of Acanthamoeba cDNA library. The Acanthamoeba EST DB contains 3,897 EST generated from amebae under various conditions of long term in vitro culture, mouse brain passage, or encystation, and downloaded data of Acanthamoeba from National Center for Biotechnology Information (NCBI) and Taxonomically Broad EST Database (TBestDB). The almost reported cDNA/genomic sequences of Acanthamoeba provide stand alone BLAST system with nucleotide (BLAST NT) and amino acid (BLAST AA) sequence database. In BLAST results, each gene links for the significant information including sequence data, gene orthology annotations, relevant references, and a BlastX result. This is the first attempt for construction of Acanthamoeba database with genes expressed in diverse conditions. These data were integrated into a database (http://www.amoeba.or.kr).

Keratitis by Acanthamoeba triangularis: report of cases and characterization of isolates.

Three Acanthamoeba isolates (KA/E9, KA/E17, and KA/E23) from patients with keratitis were identified as Acanthamoeba triangularis by analysis of their molecular characteristics, a species not previously recognized to be a corneal pathogen. Epidemiologic significance of A. triangularis as a keratopathogen in Korea has been discussed. Morphologic features of Acanthamoeba cysts were examined under a microscope with differential interference contrast (DIC) optics. Mitochondrial DNA (mtDNA) of the ocular isolates KA/E9, KA/E17, and KA/E23 were digested with restriction enzymes, and the restriction patterns were compared with those of reference strains. Complete nuclear 18S and mitochondrial (mt) 16S rDNA sequences were subjected to phylogenetic analysis and species identification. mtDNA RFLP of 3 isolates showed very similar patterns to those of SH621, the type strain of A. triangularis. 16S and 18S rDNA sequence analysis confirmed 3 isolates to be A. triangularis. 18S rDNA sequence differences of the isolates were 1.3% to 1.6% and those of 16S rDNA, 0.4% to 0.9% from A. triangularis SH621. To the best of our knowledge, this is the first report, confirmed by 18S and 16S rDNA sequence analysis, of keratitis caused by A. triangularis of which the type strain was isolated from human feces. Six isolates of A. triangularis had been reported from contaminated contact lens cases in southeastern Korea.

Molecular characterization of bacterial endosymbionts of Acanthamoeba isolates from infected corneas of Korean patients.

The endosymbionts of 4 strains of Acanthamoeba (KA/E9, KA/E21, KA/E22, and KA/E23) isolated from the infected corneas of Korean patients were characterized via orcein stain, transmission electron microscopic examination, and 16S rDNA sequence analysis. Double membrane-bound, rod-shaped endosymbionts were distributed randomly throughout both the trophozoites and cysts of each of Acanthamoeba isolates. The endosymbionts of KA/E9, KA/E22, and KA/E23 were surrounded by electron-translucent areas. No lacunae-like structures were observed in the endosymbionts of KA/E21, the bacterial cell walls of which were studded with host ribosomes. Comparative analyses of the 16S rDNA sequences showed that the endosymbionts of KA/E9, KA/E22 and KA/E23 were closely related to Caedibacter caryophilus, whereas the KA/E21 endosymbiont was assigned to the Cytophaga-Flavobacterium-Bacteroides (CFB) phylum. In the 4 strains of Acanthamoeba, the hosts of the endosymbionts were identified as belonging to the Acanthamoeba castellanii complex, which corresponds to the T4 genotype. Acanthamoeba KA/E21 evidenced characteristics almost identical to those of KA/E6, with the exception of the existence of endosymbionts. The discovery of these endosymbionts from Acanthamoeba may prove essential to future studies focusing on interactions between the endosymbionts and the amoebic hosts.