Time to Treat First Acute Attack of Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease.

Importance: A proportion of people with myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) have a relapsing disease course and persistent anti-myelin oligodendrocyte glycoprotein immunoglobulin G (MOG-IgG) seropositivity. Few studies have investigated whether treatment of the first MOGAD attack is associated with the long-term disease course and/or MOG-IgG seronegative conversion. Objective: To investigate the association of time to treat the first acute MOGAD attack with relapse risk and MOG-IgG serostatus. Design, Setting, and Participants: This was a retrospective, nationwide, multicenter cohort study involving 14 secondary or tertiary hospitals in South Korea between November 2009 and August 2023. People with adult-onset MOGAD, who either had a relapse or were followed up for more than 12 months after disease onset and had a detailed medical record of their first attack, were included. Individuals were excluded for adolescent-onset MOGAD or short disease duration. Exposures: Patients were categorized based on the time to treat the first acute MOGAD attack: early (<5 days), intermediate (5-14 days), and late (not treated within 14 days). Main Outcomes and Measures: A multivariable analysis for clinical and treatment factors associated with relapsing disease course and/or MOG-IgG seronegative conversion. Further subgroup analyses were conducted among those without long-term nonsteroidal immunosuppressant (NSIS) maintenance treatment. Results: Among the 315 individuals screened, 75 were excluded. A total of 240 patients (median [IQR] age at onset, 40.4 [28.8-56.1] years; 125 female [52.1%]) with median (IQR) disease duration of 3.07 (1.95-6.15) years were included. A total of 110 of 240 patients (45.8%) relapsed after a median (IQR) of 0.45 (0.18-1.68) years, and 29 of 116 patients (25.0%) experienced a conversion to seronegative MOG-IgG. Both the time to treatment of the first MOGAD attack (late vs early: adjusted hazard ratio [aHR], 2.64; 95% CI, 1.43-4.84; P = .002; intermediate vs early: aHR, 2.02; 95% CI, 1.10-3.74; P = .02) and NSIS maintenance treatment (aHR, 0.24; 95% CI, 0.14-0.42; P < .001) were independently associated with the risk of relapse. In a subgroup without NSIS maintenance, the time to treat of the first MOGAD attack was still associated with higher risk of relapse (late vs early: aHR, 3.51; 95% CI, 1.64-7.50; P = .001; intermediate vs early: aHR, 2.68; 95% CI, 1.23-5.85; P = .01). Lastly, the time to treat of the first MOGAD attack was also associated with MOG-IgG seronegative conversion (early vs late: adjusted odds ratio, 7.04; 95% CI, 1.58-31.41; P = .01), whereas NSIS maintenance treatment was not. Conclusions and Relevance: Results of this cohort study suggest that early treatment of the first acute MOGAD attack was associated with a reduction in the proportion of relapsing disease course and an increase in the likelihood of MOG-IgG seronegative conversion. These data suggest that timing of acute phase treatment for the first MOGAD attack can be associated with the long-term prognosis and autoimmune status of patients.

Description of Conchophthirus sinanodontae n. sp. (Ciliophora: Scuticociliatia), a new endocommensal ciliate of the freshwater mussel Sinanodonta woodiana from Korea.

The morphology and molecular phylogeny of a new ciliate, Conchophthirus sinanodontae n. sp., which was discovered in the freshwater mussel Sinanodonta woodiana (Lea, 1834) from the Chilsancheon River, Buyeo-gun, South Korea, were investigated. The new species was characterized and could be distinguished from congeners by a combination of characters including the ovate body outline, four to six oral polykinetids deeply embedded in the upper wall of the buccal cavity, six to ten vestibular kineties, 34-49 ventral and 36-53 dorsal somatic kineties. The genetic differences among C. sinanodontae n. sp. and other congeners with available 18S rDNA sequences further support its distinctness. Moreover, the phylogenetic analyses based on the 18S rDNA sequences show that the new species clusters with other congeners, corroborating the monophyly of the genus Conchophthirus. The Conchophthirus clade nests within the cluster of Dexiotricha spp., Loxocephalus luridus, and Haptophrya spp.

Recurrence-Independent Progressive Inner-Retinal Thinning After Optic Neuritis: A Longitudinal Study.

BACKGROUND: Longitudinal changes in the inner retina in patients with optic neuritis (ON) may be helpful in monitoring patients and determining maintenance treatment. The aim of this study was to investigate longitudinal changes in the inner retina after subsiding of acute demyelinating ON and to identify the factors associated with such changes. METHODS: In this multicenter retrospective observational study, we reviewed the medical records of 77 patients with ON, including 23 with neuromyelitis optica spectrum disorder with aquaporin 4 (AQP4)-immunoglobulin G (IgG) (AQP4 group), 23 with myelin oligodendrocyte glycoprotein (MOG)-antibody-associated disease (MOG group), 18 with multiple sclerosis (MS group), and 13 with idiopathic ON (iON group). We measured the thickness of the peripapillary retinal nerve fiber layer (pRNFL) and the macular ganglion cell-inner plexiform layer (mGCIPL) using optical coherence tomography (OCT) at baseline and at follow-up examinations (mean follow-up duration, 29.6 ± 8.6 months; mean number of OCT, 4.2 ± 1.2) in the absence of ON recurrence. RESULTS: The estimated rate of pRNFL thinning in the AQP4, MOG, MS, and iON groups was 0.66 (95% confidence interval, 0.35-0.97), 0.35 (0.04-0.66), 0.53 (0.16-0.90), and 0.25 (-0.18 to 0.68) µm/year, respectively, indicating that, in the iON group in contrast to the other groups, there was no significant decrease of pRNFL thickness. Among the AQP4, MOG, and MS groups, there was no significant difference in the rate of pRNFL thinning (P = 0.560). The rate of mGCIPL thinning in the AQP4 and MOG groups was 0.25 (0.04-0.46) µm/year and 0.38 (0.23-0.53) µm/year, respectively. Meanwhile, the rate of mGCIPL change in the MS and iON groups was 0.04 (-0.12 to 0.19) and 0.00 (-0.17 to 0.16) µm/year, respectively, which indicates that there was no significant mGCIPL thinning in the latter 2 groups. Between the AQP4 and MOG groups, meanwhile, the rate of mGCIPL change did not significantly differ (P = 0.295). Age older than 40 years was associated with significant progression of mGCIPL thinning (P = 0.005). CONCLUSIONS: We noted inner retina thinning progression independent of relapse activity in AQP4-ON, MOG-ON, and MS-ON. Because subclinical neuroaxonal damage continues to be incurred after an acute attack of ON subsides despite suppression of new attacks, long-term follow-up and neuroprotection should be considered to be integral to the treatment of patients with ON.

Morphology and molecular phylogeny of Euplotes baugilensis n. sp. (Ciliophora, Spirotrichea), with an illustrated key to Euplotes species with reduced cirri.

Euplotes baugilensis n. sp. was discovered in a temporary puddle that formed after rainfall on a mountain footpath near Gangneung-Wonju National University in Gangneung, South Korea. After isolation, a pure culture was established, and the new species was examined using live observation, silver-impregnation (protargol and 'wet' silver nitrate), scanning electron microscopy, and the analysis of the 18S rRNA gene sequence. Morphologically, E. baugilensis n. sp. is characterized by small body size (on average 49 × 31 µm in vivo), 9 ordinary fronto-ventral cirri (cirrotype-9) with one reduced cirrus V/2 (composed of four non-ciliated basal bodies), 5 transverse cirri, 7 or 8 dorsolateral kineties, 6 dorsal prominent ridges, and a dargyrome (silverline system) of double type. In this study, we have used a combination of morphological and molecular techniques to characterize E. baugilensis n. sp. and determine its phylogenetic position within the genus Euplotes. Molecular analysis using 18S rRNA gene sequences indicated that E. baugilensis n. sp. is most closely related to E. curdsi (with a sequence identity of 96.8 %).

EUKARYOME: the rRNA gene reference database for identification of all eukaryotes.

Molecular identification of micro- and macroorganisms based on nuclear markers has revolutionized our understanding of their taxonomy, phylogeny and ecology. Today, research on the diversity of eukaryotes in global ecosystems heavily relies on nuclear ribosomal RNA (rRNA) markers. Here, we present the research community-curated reference database EUKARYOME for nuclear ribosomal 18S rRNA, internal transcribed spacer (ITS) and 28S rRNA markers for all eukaryotes, including metazoans (animals), protists, fungi and plants. It is particularly useful for the identification of arbuscular mycorrhizal fungi as it bridges the four commonly used molecular markers-ITS1, ITS2, 18S V4-V5 and 28S D1-D2 subregions. The key benefits of this database over other annotated reference sequence databases are that it is not restricted to certain taxonomic groups and it includes all rRNA markers. EUKARYOME also offers a number of reference long-read sequences that are derived from (meta)genomic and (meta)barcoding-a unique feature that can be used for taxonomic identification and chimera control of third-generation, long-read, high-throughput sequencing data. Taxonomic assignments of rRNA genes in the database are verified based on phylogenetic approaches. The reference datasets are available in multiple formats from the project homepage, http://www.eukaryome.org.

Variability of relationship between inner-retinal structural changes and visual dysfunction in optic neuropathy.

Optical coherence tomography (OCT) displays the retinal nerve fiber layer (RNFL) or macular ganglion cell and inner plexiform layer (GCIPL) thickness below 1st percentile in red color. This finding generally indicates severe inner-retinal structural changes and suggests poor visual function. Nevertheless, some individuals show preserved visual function despite these circumstances. This study aimed to identify the correlation between best-corrected visual acuity (BCVA) and inner-retinal thickness based on OCT parameters in various optic neuropathy patients with extremely low RNFL/GCIPL thickness, and determine the limitation of OCT for predicting visual function in these patients. 131 patients were included in the study. The mean BCVA in logMAR was 0.55 ± 0.70 with a broad range from - 0.18 to 3.00. Among the OCT parameters, temporal GCIPL (r = - 0.412) and average GCIPL (r = - 0.366) exhibited the higher correlations with BCVA. Etiological comparisons of optic neuropathies revealed significantly lower BCVA in LHON (all p < 0.05). Idiopathic optic neuritis (ON) and MOGAD exhibited better and narrower BCVA distributions compared to the other optic neuropathies. OCT had limited utility in reflecting BCVA, notwithstanding significant inner-retinal thinning after optic nerve injuries. Caution is needed in interpreting OCT findings, especially as they relate to the etiology of optic neuropathy.

Comparison of macular changes according to the etiology of optic neuritis: a cross-sectional study.

AIM: To compare the macular structure including foveal thickness among patients with optic neuritis (ON) according to the etiology and to investigate the possible correlation between structural and visual outcomes. METHODS: In this retrospective cross-sectional study, the clinical data of patients with aquaporin-4 immunoglobulin G-related ON (AQP4 group, 40 eyes), myelin oligodendrocyte glycoprotein IgG-related ON (MOG group, 31 eyes), and multiple sclerosis-related ON (MS group, 24 eyes) were obtained. The retinal thickness of the foveal, parafoveal and perifoveal regions were measured. Visual acuity (VA), visual field index and mean deviation were measured as visual outcomes. RESULTS: The AQP4 group showed a significantly thinner fovea (226.4±13.4 µm) relative to the MOG (236.8±14.0 µm, P=0.015) and MS (238.9±14.3 µm, P=0.007) groups. The thickness in the parafoveal area also was thinner in the AQP4 group, though the difference in perifoveal retinal thickness was not significant. Foveal thickness was correlated with VA in the AQP4 group (coefficient ρ=-0.418, P=0.014), but not in the MOG and MS groups (P=0.218 and P=0.138, respectively). There was no significant correlation between foveal thickness and visual field test in all three groups. CONCLUSION: The significant thinning in the fovea and parafoveal areas in the AQP4 group compared to the MOG and MS groups are found. Additionally, macular changes in AQP4-ON show a significant correlation with VA. The results provide the possibility that retinal structural damage could reflect functional damage in AQP4-ON, distinct from MOG-ON and MS-ON.

Prediction of neovascular age-related macular degeneration recurrence using optical coherence tomography images with a deep neural network.

Neovascular age-related macular degeneration (nAMD) can result in blindness if left untreated, and patients often require repeated anti-vascular endothelial growth factor injections. Although, the treat-and-extend method is becoming popular to reduce vision loss attributed to recurrence, it may pose a risk of overtreatment. This study aimed to develop a deep learning model based on DenseNet201 to predict nAMD recurrence within 3 months after confirming dry-up 1 month following three loading injections in treatment-naïve patients. A dataset of 1076 spectral domain optical coherence tomography (OCT) images from 269 patients diagnosed with nAMD was used. The performance of the model was compared with that of 6 ophthalmologists, using 100 randomly selected samples. The DenseNet201-based model achieved 53.0% accuracy in predicting nAMD recurrence using a single pre-injection image and 60.2% accuracy after viewing all the images immediately after the 1st, 2nd, and 3rd injections. The model outperformed experienced ophthalmologists, with an average accuracy of 52.17% using a single pre-injection image and 53.3% after examining four images before and after three loading injections. In conclusion, the artificial intelligence model demonstrated a promising ability to predict nAMD recurrence using OCT images and outperformed experienced ophthalmologists. These findings suggest that deep learning models can assist in nAMD recurrence prediction, thus improving patient outcomes and optimizing treatment strategies.

Redescription and molecular phylogeny of Trochilia sigmoides Dujardin, 1841 (Ciliophora, Cyrtophoria) collected from South Korea.

During a survey of Korean marine ciliates, Trochilia sigmoides, the type species of the genus Trochilia, was collected and examined using in vivo observation and protargol impregnation. Moreover, scanning electron microscopy and 18S rRNA gene sequencing have been applied for the first time to study this species. Morphologically, T. sigmoides is characterized by the small body size, the oval body outline, and the spiral dorsal ridges. The Korean population of T. sigmoides shows only minute differences to other populations reported in the literature, mainly in body size and the number of dorsal ridges. Phylogenetic analyses based on 18S rRNA gene sequences show that T. sigmoides and T. petrani are placed together with two members of the family Kyaroikeidae, causing the family Dysteriidae to be non-monophyletic. The present new data increase the knowledge about the morphology and phylogeny of the genus Trochilia and would assist in understanding the phylogenetic relationship between the free-living Dysteriidae and the parasitic Kyaroikeidae.

Prognostic factors of first-onset optic neuritis based on diagnostic criteria and antibody status: a multicentre analysis of 427 eyes.

BACKGROUND: Optic neuritis (ON) prognosis is influenced by various factors including attack severity, underlying aetiologies, treatments and consequences of previous episodes. This study, conducted on a large cohort of first ON episodes, aimed to identify unique prognostic factors for each ON subtype, while excluding any potential influence from pre-existing sequelae. METHODS: Patients experiencing their first ON episodes, with complete aquaporin-4 (AQP4) and myelin oligodendrocyte glycoprotein (MOG) antibody testing, and clinical data for applying multiple sclerosis (MS) diagnostic criteria, were enrolled. 427 eyes from 355 patients from 10 hospitals were categorised into four subgroups: neuromyelitis optica with AQP4 IgG (NMOSD-ON), MOG antibody-associated disease (MOGAD-ON), ON in MS (MS-ON) or idiopathic ON (ION). Prognostic factors linked to complete recovery (regaining 20/20 visual acuity (VA)) or moderate recovery (regaining 20/40 VA) were assessed through multivariable Cox regression analysis. RESULTS: VA at nadir emerged as a robust prognostic factor for both complete and moderate recovery, spanning all ON subtypes. Early intravenous methylprednisolone (IVMP) was associated with enhanced complete recovery in NMOSD-ON and MOGAD-ON, but not in MS-ON or ION. Interestingly, in NMOSD-ON, even a slight IVMP delay in IVMP by >3 days had a significant negative impact, whereas a moderate delay up to 7-9 days was permissible in MOGAD-ON. Female sex predicted poor recovery in MOGAD-ON, while older age hindered moderate recovery in NMOSD-ON and ION. CONCLUSION: This comprehensive multicentre analysis on first-onset ON unveils subtype-specific prognostic factors. These insights will assist tailored treatment strategies and patient counselling for ON.

Risk of central nervous system demyelinating attack or optic neuritis recurrence after pediatric optic neuritis in Korea.

PURPOSE: To investigate the rate of development of symptomatic central nervous system (CNS) demyelinating attacks or recurrent optic neuritis (ON) after the first episode of ON and its risk factors for Korean pediatric patients. METHODS: This multicenter retrospective cohort study included the patients under 18 years of age (n=132) diagnosed with ON without previous or simultaneous CNS demyelinating diseases. We obtained the clinical data including the results of neuro-ophthalmological examinations, magnetic resonance images (MRIs), antibody assays, and laboratory tests. We investigated the chronological course of demyelinating disease with respect to the occurrence of neurological symptoms and/or signs, and calculated the 5-year cumulative probability of CNS demyelinating disease or ON recurrence.  RESULTS: During the follow-up period (63.1±46.7 months), 18 patients had experienced other CNS demyelinating attacks, and the 5-year cumulative probability was 14.0±3.6%. Involvement of the extraorbital optic nerve or optic chiasm and asymptomatic lesions on the brain or spinal MRI at initial presentation were significant predictors for CNS demyelinating attack after the first ON. The 5-year cumulative probability of CNS demyelinating attack was 44.4 ± 24.8% in the AQP4-IgG group, 26.2±11.4% in the MOG-IgG group, and 8.7±5.9% in the double-negative group (P=0.416). Thirty-two patients had experienced a recurrence of ON, and the 5-year cumulative probability was 24.6±4.0%. In the AQP4-IgG group, the 5-year cumulative probability was 83.3±15.2%, which was significantly higher than in the other groups (P<0.001). CONCLUSIONS: A careful and multidisciplinary approach including brain/spinal imaging and antibody assay can help predict further demyelinating attacks in pediatric ON patients.

Morphology and molecular phylogeny of two hypotrichous ciliates (Ciliophora, Spirotrichea) from South Korea, including Hemiurosomoida koreana n. sp.

The living morphology, infraciliature, and molecular phylogeny of a new soil ciliate, Hemiurosomoida koreana n. sp., discovered in a sample collected from a mountain in the northeast of South Korea, were investigated. The new species possesses the characteristics of the genus Hemiurosomoida, i.e., a reduced number of frontal-ventral-transverse cirri, three dorsal kineties of which kineties 1 and 2 each bears a caudal cirrus, and a single dorsomarginal kinety. It is distinguishable from congeners and other similar species by at least one distinct qualitative or quantitative character including the body size, the presence and arrangement of cortical granules, the number of adoral membranelles, marginal cirri, and dorsal dikinetids, or by the arrangement of transverse cirri. Phylogenetic analyses based on 18S rRNA gene sequences also support the assignment of the new species to the non-monophyletic genus Hemiurosomoida. In addition, the living morphology, infraciliature, and the 18S rRNA gene sequence of a Korean population of Nothoholosticha flava were studied.

Morphology, morphogenesis, and molecular phylogeny of Aspidisca koreana n. sp. (Ciliophora, Euplotida) from South Korea.

The morphology, morphogenesis, and molecular phylogeny of a new ciliate, Aspidisca koreana n. sp., discovered in the eastern coast of South Korea, were investigated. The morphological description is based on the observation of living cells, 4'-6-diamidino-2-phenylindole (DAPI) and silver-stained specimens (e.g., protargol, silver nitrate), and scanning electron micrographs. The new species is characterized by having a small body size (17-25 × 15-18 µm in vivo), a distinct peristomial spur on the posterior portion of left margin, seven frontoventral cirri in "polystyla-arrangement", and the arrangement of the anterior portion of adoral zone of membranelles, i.e., anteriormost membranelle is distinctly separated from the other three membranelles. The morphogenesis follows the typical pattern of this genus. Phylogenetic analyses, using the 18S rDNA sequence, also support the establishment of a new species.

Report on the seventh meeting of national control laboratories for vaccines and biologicals of the WHO Western Pacific and South-East Asia member states.

The Biregional Network of National Control Laboratories (NCLs) of the WHO Western Pacific and South-East Asia Regions has been meeting annually since 2018 to enhance NCLs' voluntary participation capacity. Its seventh meeting was hosted by the Korea National Institute of Food and Drug Safety Evaluation (NIFDS) of the Ministry of Food and Drug Safety (MFDS), in conjunction with the Global Bio Conference, in Seoul on September 6, 2022. Over 60 participants from seven countries, (India, Indonesia, Japan, Korea, Malaysia, the Philippines, and Vietnam) attended the meeting on-site and online. The theme of this meeting was 'Quality Control Issues and International Trends for Biologicals including Vaccines and Plasma-Derived Medicinal Products.' Three special speeches were presented on sharing the quality control system for biologicals, including NCLs' considerations in preparing the WHO Listed Authorities and sharing MFDS experiences. Furthermore, the participating NCLs shared country-specific issues related to national lot releases during the COVID-19 pandemic and acknowledged the meeting's crucial role in response preparedness for pandemic emergencies and enhancing regulatory capacity through coalitions and information exchange among NCLs. The NIFDS will cooperate closely with other Asian NCLs to enhance biological product quality control, aiming to establish regional standards and standardize test methods through collaboration.

Extraocular muscle enlargement of indeterminate cause in pediatric patients: case series and literature review.

PURPOSE: To specify the clinical characteristics of enlarged extraocular muscles of indeterminate cause in pediatric patients based on a case series and literature review. METHODS: The medical records of pediatric patients who presented between January 2019 and January 2022 with enlarged extraocular muscles, where the underlying cause could not be determined, were retrospectively reviewed. RESULTS: Four patients were included. The main reason for presentation was evaluation of abnormal head posture. Head tilt or turn with duction deficit was observed in all patients. The age of onset ranged from 6 months to 1 year. Two patients presented with esotropia and hypotropia; the other 2 patients, with large-angle esotropia. Orbital imaging was performed in all cases and revealed unilateral rectus muscle enlargement sparing the muscle tendon. All 4 patients were found to have an enlarged medial rectus muscle. In the 2 patients with hypotropia, the inferior rectus muscle was also involved. No underlying systemic or orbital disease was found. There were no changes in the orbit or extraocular muscles on follow-up imaging test. The intraoperative forced duction test revealed severe restriction in the direction of gaze opposite to the primary field of action of the enlarged muscles. CONCLUSIONS: Enlargement of extraocular muscles should be considered in the differential diagnosis when large-angle incomitant vertical or horizontal misalignment and abnormal head posture are observed in infancy.

Brain natriuretic peptide as a clinical screening tool for the diagnosis of Kawasaki disease.

N-terminal pro-brain natriuretic peptide (NT-proBNP) has been studied as a diagnostic screening tool for Kawasaki disease (KD). However, brain natriuretic peptide (BNP) has been less studied while has less variability among age groups. We aimed to find out if BNP can be used as a diagnostic screening tool for KD in Korea. This was a retrospective cohort study performed in a single pediatric emergency department. Patients younger than 19 years of age who presented with fever and underwent BNP examination for suspected KD was included. The primary outcome was the diagnostic performance of BNP for KD, and the secondary outcome was the diagnostic performance of BNP for coronary artery aneurysm (CAA). We also derived a scoring system for predicting KD and CAA. Of the 778 patients who were finally included, 400 were not diagnosed with KD and 378 were diagnosed with KD. The odds ratio of BNP at the cutoff of 30 pg/mL for KD was 7.80 (95% CI, 5.67-10.73) in the univariate analysis and 3.62 (95% CI, 2.33-5.88) in the multivariable analysis. The odds ratio of BNP at the cutoff of 270 pg/mL for CAA was 3.67 (95% CI, 2.18-6.19) in the univariate analysis and 2.37 (95% CI, 1.16-8.74) in the multivariable analysis. The AUC of KD and CAA were 0.884 and 0.726, respectively, which was the highest AUCs among all variables. Additionally, we proposed a scoring system for KD and CAA. It is important to clinically suspect KD and CAA in children with high BNP levels.

Polymorphism, gigantism, and cannibalism, one stylonychid ciliate (Ciliophora, Hypotricha) to rule them all.

The morphology, ontogenesis, and molecular phylogeny of the polymorphic and cannibalistic giant forming Tetmemena polymorpha n. sp., found in a brackish water sample in South Korea, were investigated. The present species has long been misidentified as "Oxytricha bifaria." The new investigation shows that the species produces three morphologically different morphs. The small morph is bacterivorous and characterized by its small body size and slim body and it is found only in the stationary and decline phases of the culture. The large morph has a wide body, larger oral apparatus, and feeds on small eukaryotes such as yeast cells and small ciliates. It divides very quickly and produces the other two morphs and found in the exponential phase of the cultures. The giant morph is characterized by its huge body and oral apparatus. It feeds on the small morph cells of the same species and other ciliates, and occurs together with the small morph. Phylogenetic analyses based on the 18S rRNA gene sequences show that the new species is placed in a sister subclade to that containing other Tetmemena sequences. Moreover, Tetmemena indica Bharti et al., 2019 nov. stat. is raised to species level based on the differences in the cyst morphology and the dorsal ciliature to the authoritative Tetmemena pustulata population.

Synthesis, In Silico and In Vitro Characterization of Novel N,N-Substituted Pyrazolopyrimidine Acetamide Derivatives for the 18KDa Translocator Protein (TSPO).

The translocator protein (TSPO) is an interesting biological target for molecular imaging and therapy because the overexpression of TSPO is associated with microglial activation caused by neuronal damage or neuroinflammation, and these activated microglia are involved in various central nervous system (CNS) diseases. The TSPO is a target for neuroprotective treatment, which is used with the aim of reducing microglial cell activation. The novel N,N-disubstituted pyrazolopyrimidine acetamides scaffold (GMA 7-17), which bears a fluorine atom and is directly linked to the phenyl moiety, was synthesized, and each of the novel ligands was characterized in vitro. All of the newly synthesized ligands displayed picomolar to nanomolar affinity for the TSPO. Particularly, an in vitro affinity study led to the discovery of 2-(5,7-diethyl-2-(4-fluorophenyl)pyrazolo [1,5-a]pyrimidin-3-yl)-N-ethyl-N-phenylacetamide GMA 15 (Ki = 60 pM), a novel TSPO ligand that exhibits a 61-fold enhancement in affinity compared to the reference standard DPA-714 (Ki = 3.66 nM). Molecular dynamic (MD) studies of the highest affinity binder, GMA 15, were carried out to check its time-dependent stability with the receptor compared to DPA-714 and PK11195. The hydrogen bond plot also indicated that GMA 15 formed higher hydrogen bonds compared to DPA-714 and PK11195. We anticipate that further optimization to enhance the potency in a cellular assay needs to be followed, but our strategy of identifying potential TSPO binding novel scaffolds may open up a new avenue to develop novel TSPO ligands suited for potential molecular imaging and a wide range of therapeutic applications.