[Hypervascular Tumors such as Hemangioblastoma].

Hemangioblastomas are richly vascular tumors. Therefore, visualizing the vascular anatomy of their feeders and drainers is important for planning surgical excision. Preoperative three-dimensional computer graphic(3DCG)images are useful for determining the number, location, and course of their feeders and drainers.

Links between cholesteryl sulfate-dependent and -independent processes in the morphological and physiological changes of Entamoeba encystation.

The protozoan parasite Entamoeba histolytica causes amoebiasis, a global public health problem. Amoebiasis is solely transmitted by cysts that are produced from proliferative trophozoites by encystation in the large intestine of humans. During encystation, various metabolites, pathways, and cascades sequentially orchestrate the morphological and physiological changes required to produce cysts. Cholesteryl sulfate (CS) has recently been revealed to be among the key molecules that control the morphological and physiological changes of encystation by exerting pleiotropic effects. CS promotes the rounding of encysting Entamoeba cells and maintains this spherical morphology as encysting cells are surrounded by the cyst wall, a prerequisite for resistance against environmental stresses. CS is also involved in the development of membrane impermeability, another prerequisite for resistance. The initiation of cyst wall formation is, however, CS-independent. Here, we overview CS-dependent and -independent processes during encystation and discuss their functional linkage. We also discuss a potential transcriptional cascade that controls the processes necessary to produce dormant Entamoeba cysts.

IL-27 produced during acute malaria infection regulates Plasmodium-specific memory CD4+ T cells.

Malaria infection elicits both protective and pathogenic immune responses, and IL-27 is a critical cytokine that regulate effector responses during infection. Here, we identified a critical window of CD4+ T cell responses that is targeted by IL-27. Neutralization of IL-27 during acute infection with Plasmodium chabaudi expanded specific CD4+ T cells, which were maintained at high levels thereafter. In the chronic phase, Plasmodium-specific CD4+ T cells in IL-27-neutralized mice consisted mainly of CD127+ KLRG1- and CD127- KLRG1+ subpopulations that displayed distinct cytokine production, proliferative capacity, and are maintained in a manner independent of active infection. Single-cell RNA-seq analysis revealed that these CD4+ T cell subsets formed independent clusters that express unique Th1-type genes. These IL-27-neutralized mice exhibited enhanced cellular and humoral immune responses and protection. These findings demonstrate that IL-27, which is produced during the acute phase of malaria infection, inhibits the development of unique Th1 memory precursor CD4+ T cells, suggesting potential implications for the development of vaccines and other strategic interventions.

Effects of Bovine Lactoferrin on the Maintenance of Respiratory and Systemic Physical Conditions in Healthy Adults-A Randomized, Double-Blind, Placebo-Controlled Trial.

OBJECTIVES: We investigated the effects of bovine lactoferrin (LF) on the maintenance of the respiratory and systemic physical conditions. METHODS: A randomized, double-blind, placebo-controlled trial was conducted. Healthy adults at Kyushu University of Health and Welfare ingested a placebo or bovine LF (200 mg/day) for 12 weeks. The primary endpoints were the total respiratory and systemic symptom scores. The secondary endpoint was the activity of plasmacytoid dendritic cells (pDCs) in peripheral blood. RESULTS: A total of 157 subjects were randomized (placebo, n = 79; LF, n = 78), of whom, 12 dropped out. The remaining 145 participants were included in the full analysis set (placebo group, n = 77; LF group, n = 68). The total scores for respiratory and systemic symptoms during the intervention were significantly lower in the LF group than in the placebo group. The expression of CD86 and HLA-DR on pDCs was significantly higher in the LF group than in the placebo group at week 12. Adverse events were comparable between the groups, and no adverse drug reactions were observed. CONCLUSIONS: These results suggest that orally ingested LF supports the normal immune system via maintaining pDC activity, and maintains respiratory and systemic physical conditions in healthy adults.

Effects of others' gaze and facial expression on an observer's microsaccades and their association with ADHD tendencies.

BACKGROUND: The aim of this study was to examine the effect of others' gaze on an observer's microsaccades. We also aimed to conduct preliminary investigations on the relationship between the microsaccadic response to a gaze and a gazer's facial expression and attention-deficit/hyperactivity disorder (ADHD) tendencies. METHODS: Twenty healthy undergraduate and graduate students performed a peripheral target detection task by using unpredictable gaze cues. During the task, the participants' eye movements, along with changes in pupil size and response times for target detection, were recorded. ADHD tendencies were determined using an ADHD questionnaire. RESULTS: We found that consciously perceiving the gaze of another person induced the observer's attention; moreover, microsaccades were biased in the direction opposite to the gaze. Furthermore, these microsaccade biases were differentially modulated, based on the cognitive processing of the facial expressions of the gaze. Exploratory correlation analysis indicated that microsaccade biases toward gazes with fearful expressions may specifically be correlated with participant characteristics, including inattention. CONCLUSIONS: Our findings support that microsaccades reflect spatial attention processing and social cognitive processing. Moreover, the exploratory correlation analysis results suggested the potential benefit of using microsaccade bias toward spatial attention to assess pathophysiological responses associated with ADHD tendencies.

CD47 promotes peripheral T cell survival by preventing dendritic cell-mediated T cell necroptosis.

Conventional dendritic cells (cDCs) are required for peripheral T cell homeostasis in lymphoid organs, but the molecular mechanism underlying this requirement has remained unclear. We here show that T cell-specific CD47-deficient (Cd47 ΔT) mice have a markedly reduced number of T cells in peripheral tissues. Direct interaction of CD47-deficient T cells with cDCs resulted in activation of the latter cells, which in turn induced necroptosis of the former cells. The deficiency and cell death of T cells in Cd47 ΔT mice required expression of its receptor signal regulatory protein α on cDCs. The development of CD4+ T helper cell-dependent contact hypersensitivity and inhibition of tumor growth by cytotoxic CD8+ T cells were both markedly impaired in Cd47 ΔT mice. CD47 on T cells thus likely prevents their necroptotic cell death initiated by cDCs and thereby promotes T cell survival and function.

Unique features of Entamoeba histolytica glycerophospholipid metabolism; has the E. histolytica lipid metabolism network evolved through gene loss and gain to enable parasitic life cycle adaptation?

Entamoeba histolytica, a protozoan parasite, causes amoebiasis, which is a global public health problem. During the life cycle of this parasite, the properties of the cell membrane are changed markedly. To clarify the mechanism of membrane lipid changes, we exploited state-of-the-art untargeted lipidomic analysis, and atypical features of glycerophospholipids, lysoglycerophospholipids, and sphingolipids were observed compared with human equivalents. Here, we overview an entire E. histolytica glycerophospholipid metabolic pathway based on re-evaluated whole lipidome and genome along with the results of metabolic labeling experiments. We also discuss whether the E. histolytica lipid metabolism network, including the glycerophospholipid metabolic pathway, has unique features necessary for parasitic life cycle adaptation through gene loss and/or gain, and raise important questions involving biochemistry, molecular cell biology, and physiology underlying this network. Answering these questions will advance the understanding of Entamoeba physiology and will provide potential targets to develop new anti-amoebiasis drugs.

Effects of inhalation of multi-walled carbon nanotube (MWCNT) on respiratory syncytial virus (RSV) infection in mice.

Multi-walled carbon nanotubes (MWCNTs), a kind of nanomaterial, are widely used in battery electrodes and composite materials, but the adverse effects associated with their accumulation in the living body have not been sufficiently investigated. MWCNTs are a fibrous material with molecules similar to asbestos fibers, and there are concerns about its effects on the respiratory system. In this study, we conducted a risk assessment by exposing mice using a previously developed nanomaterial inhalation exposure method. We quantified the exposure in the lungs by a lung burden test, evaluated the deterioration due to pneumonia using respiratory syncytial virus (RSV) infection, and measured inflammatory cytokines in bronchoalveolar lavage fluid (BALF). As a result, in the lung burden test, the amount of MWCNT in the lung increased according to the inhalation dose. In the RSV infection experiment, CCL3, CCL5, and TGF-ß, which are indicators of inflammation and lung fibrosis, were elevated in the MWCNT-exposed group. Histological examination revealed cells phagocytosing MWCNT fibers. These phagocytic cells were also seen during the recovery period from RSV infection. The present study found that MWCNT remained in the lungs for about a month or more, suggesting that the fibers may continue to exert immunological effects on the respiratory system. Furthermore, the inhalation exposure method enabled the exposure of nanomaterials to the entire lung lobe, allowing a more detailed evaluation of the effects on the respiratory system.

Possible Effect of Blonanserin Transdermal Patch on Antiemetic Control in Patients With Terminal Cancer with Refractory Nausea.

Background: Haloperidol is widely used for antiemetic control in advanced cancer. However, due to its limited administration methods (oral or injection), its management is frequently challenging in palliative home care. Recently, a blonanserin transdermal patch was developed as the first antipsychotic percutaneous agent. Objectives: This study aimed to evaluate its effectiveness and safety for refractory nausea. Methods: We conducted an observational study of 21 terminal cancer patients who had been initiated for refractory nausea in their homes. Results: After its initiation, none of the patients experienced aggravated nausea, and the number of patients with severe nausea decreased dramatically (52.4% vs. 9.5%, p = 0.008). Of 16 patients without ascites, 12.5% had not improved their nausea, which was lower than in patients with ascites (80.0%). Conclusions: Blonanserin transdermal patch has a possible effect on antiemetic control in cancer patients, and its efficacy might be particularly prominent in patients without ascites.

Efficacy of blonanserin transdermal patch on terminal delirium in patients with respiratory diseases.

BACKGROUND: Delirium is a common distressing symptom observed in patients with terminal respiratory diseases and is treated with antipsychotic medications such as haloperidol. Its management is difficult, especially in palliative home care, because its administration is limited to oral or injection methods. Recently, the blonanserin transdermal patch was developed as the first antipsychotic percutaneous agent. After it became available, we recognized its potential for the management of delirium and the alleviation of uncontrolled dyspnea in clinical practice. Thus, this study aimed to assess its efficacy in patients with terminal respiratory diseases. METHODS: This retrospective study included 113 patients with respiratory diseases who were cared for at home. The efficacy was evaluated through the prevalence of terminal delirium before and after its treatment initiation for uncontrolled dyspnea. RESULTS: Blonanserin transdermal patch treatment for uncontrolled dyspnea improved the prevalence and severity of terminal delirium (from 70.4% to 16.3%, p < 0.001) and reduced the number of doctors' visits to patients' homes within a week before their death (from 4.0 to 3.0, p = 0.086). A sub-group analysis of 23 patients with interstitial pneumonia revealed that the treatment prevented dyspnea progression by inhibiting terminal delirium. CONCLUSIONS: Blonanserin transdermal patch performed similarly to haloperidol, as previously reported, for managing terminal delirium. Our study suggests that a blonanserin transdermal patch potentially prevents terminal delirium and alleviates uncontrolled dyspnea in patients with respiratory diseases. Our findings encourage clinical trials to evaluate the safety and efficacy of blonanserin transdermal patches for patients with terminal illnesses.

Cross-ancestry genome-wide analysis of atrial fibrillation unveils disease biology and enables cardioembolic risk prediction.

Atrial fibrillation (AF) is a common cardiac arrhythmia resulting in increased risk of stroke. Despite highly heritable etiology, our understanding of the genetic architecture of AF remains incomplete. Here we performed a genome-wide association study in the Japanese population comprising 9,826 cases among 150,272 individuals and identified East Asian-specific rare variants associated with AF. A cross-ancestry meta-analysis of >1 million individuals, including 77,690 cases, identified 35 new susceptibility loci. Transcriptome-wide association analysis identified IL6R as a putative causal gene, suggesting the involvement of immune responses. Integrative analysis with ChIP-seq data and functional assessment using human induced pluripotent stem cell-derived cardiomyocytes demonstrated ERRg as having a key role in the transcriptional regulation of AF-associated genes. A polygenic risk score derived from the cross-ancestry meta-analysis predicted increased risks of cardiovascular and stroke mortalities and segregated individuals with cardioembolic stroke in undiagnosed AF patients. Our results provide new biological and clinical insights into AF genetics and suggest their potential for clinical applications.

Deep learning-based age estimation from chest X-rays indicates cardiovascular prognosis.

BACKGROUND: In recent years, there has been considerable research on the use of artificial intelligence to estimate age and disease status from medical images. However, age estimation from chest X-ray (CXR) images has not been well studied and the clinical significance of estimated age has not been fully determined. METHODS: To address this, we trained a deep neural network (DNN) model using more than 100,000 CXRs to estimate the patients' age solely from CXRs. We applied our DNN to CXRs of 1562 consecutive hospitalized heart failure patients, and 3586 patients admitted to the intensive care unit with cardiovascular disease. RESULTS: The DNN's estimated age (X-ray age) showed a strong significant correlation with chronological age on the hold-out test data and independent test data. Elevated X-ray age is associated with worse clinical outcomes (heart failure readmission and all-cause death) for heart failure. Additionally, elevated X-ray age was associated with a worse prognosis in 3586 patients admitted to the intensive care unit with cardiovascular disease. CONCLUSIONS: Our results suggest that X-ray age can serve as a useful indicator of cardiovascular abnormalities, which will help clinicians to predict, prevent and manage cardiovascular diseases.

Chest X-ray is one of the most widely used medical imaging tests worldwide to diagnose and manage heart and lung diseases. In this study, we developed a computer-based tool to predict patients' age from chest X-rays. The tool precisely estimated patients' age from chest X-rays. Furthermore, in patients with heart failure and those admitted to the intensive care unit for cardiovascular disease, elevated X-ray age estimated by our tool was associated with poor clinical outcomes, including readmission for heart failure or death from any cause. With further testing, our tool may help clinicians to predict outcomes in patients with heart disease based on a simple chest X-ray.

Thermal Effect on Thin-Film Formation of the Polymer Sheets by the CO2 Laser with the Copper Base.

A method that makes polymer sheets partially thinner with continuous-wave carbon dioxide (CO2) lasers has been developed. This method can create thin polymer films by attaching the polymer sheets to the copper base by vacuum suction through the holes in the base. Applying the method to polypropylene (PP), polyethylene terephthalate (PET), polystyrene (PS), and polytetrafluoroethylene (PTFE), the thin-film formation is confirmed in PP, PET, and PS but not PTFE. These polymers have the similar thermal properties. PP, PET, and PS show fluidity with increased temperature, but PTFE does not have fluidity. These characteristics of the polymers indicate that the fluidity of polymer is the important characteristic for film formation. The experiments with PP and PET sheets of different thickness show that thicker sheets make thicker films. The fluid flow of the molten polymer is considered to form the thin film at the bottom of the groove made by laser scribing. The numerical simulation of the 2D thermal model also indicates the week cooling effects of the base on the film formation and importance of polymer fluidity. The results of Fourier transform infrared spectrometer (FT-IR) show thermal degradation of the films. To decrease the heat's effect on the films, the polymer sheets should be processed at the highest laser-beam scanning speed that can make thin films.

Pleiotropic Roles of Cholesteryl Sulfate during Entamoeba Encystation: Involvement in Cell Rounding and Development of Membrane Impermeability.

Entamoeba histolytica, a protozoan parasite, causes amoebiasis, which is a global public health problem. The major route of infection is oral ingestion of cysts, the only form that is able to transmit to a new host. Cysts are produced by cell differentiation from proliferative trophozoites in a process termed "encystation." During encystation, cell morphology is markedly changed; motile amoeboid cells become rounded, nonmotile cells. Concomitantly, cell components change and significant fluctuations of metabolites occur. Cholesteryl sulfate (CS) is a crucial metabolite for encystation. However, its precise role remains uncertain. To address this issue, we used in vitro culture of Entamoeba invadens as the model system for the E. histolytica encystation study and identified serum-free culture conditions with CS supplementation at concentrations similar to intracellular CS concentrations during natural encystation. Using this culture system, we show that CS exerts pleiotropic effects during Entamoeba encystation, affecting cell rounding and development of membrane impermeability. CS dose dependently induced and maintained encysting cells as spherical maturing cysts with almost no phagocytosis activity. Consequently, the percentage of mature cysts was increased. CS treatment also caused time- and dose-dependent development of membrane impermeability in encysting cells via induction of de novo synthesis of dihydroceramides containing very long N-acyl chains (≥26 carbons). These results indicate that CS-mediated morphological and physiological changes are necessary for the formation of mature cysts and the maintenance of the Entamoeba life cycle. Our findings also reveal important morphological aspects of the process of dormancy and the control of membrane structure. IMPORTANCE Entamoeba histolytica causes a parasitic infectious disease, amoebiasis. Amoebiasis is a global public health problem with a high occurrence of infection and inadequate clinical options. The parasite alternates its form between a proliferative trophozoite and a dormant cyst that enables the parasite to adapt to new environments. The transition stage in which trophozoites differentiate into cysts is termed "encystation." Cholesteryl sulfate is essential for encystation; however, its precise role remains to be determined. Here, we show that cholesteryl sulfate is a multifunctional metabolite exerting pleiotropic roles during Entamoeba encystation, including the rounding of cells and the development of membrane impermeability. Such morphological and physiological changes are required for Entamoeba to produce cysts that are transmissible to a new host, which is essential for maintenance of the Entamoeba life cycle. Our findings are therefore relevant not only to Entamoeba biology but also to general cell and lipid biology.

[A case of Creutzfeldt-Jakob disease presenting with nonconvulsive status epilepticus in the early stages].

A 64-year-old Japanese woman presented with 1 week of recurrent convulsive seizures. At the time of admission, she was in a coma and did not present with convulsions. Intravenous diazepam administration improved her consciousness, although severe psychomotor excitement developed. Brain MRI demonstrated diffusion restriction in the cerebral cortex of the right hemisphere. Electroencephalography (EEG) showed periodic discharges centered around the parietal regions with right-sided dominance. Nonconvulsive status epilepticus (NCSE) was suspected, and the patient was actively treated with anti-epileptic drugs. She developed akinetic mutism and generalized myoclonus 1 month after admission. Follow-up EEG studies disclosed periodic synchronous discharges. Abnormal prion protein in the cerebral fluid was detected using a real-time quaking-induced conversion assay. The clinical diagnosis in the present case was sporadic Creutzfeldt-Jakob disease (CJD). Seizures as an initial symptom in patients with CJD are relatively rare. Our case suggests that CJD should be considered as a differential diagnosis when a patient presents with refractory NCSE.

Dynamical Lee-Yang zeros for continuous-time and discrete-time stochastic processes.

We describe classical stochastic processes by using dynamical Lee-Yang zeros. The system is in contact with external leads and the time evolution is described by the two-state classical master equation. The cumulant generating function is written in a factorized form and the current distribution is characterized by the dynamical Lee-Yang zeros. We show that a continuous distribution of zeros is obtained by discretizing the time variable. When the transition probability is a periodically oscillating function of time, the distribution of zeros splits into many parts. We study the geometric property of the current by comparing the result with that of the adiabatic approximation. We also use the Floquet-Magnus expansion in the continuous-time case to study dynamical effects on the current at the fast-driving regime.

A growing aneurysm of the posterior inferior cerebellar artery complicated with cerebellar infarction: A case report.

INTRODUCTION AND IMPORTANCE: Hereby we describe an instructive patient with cerebellar infarction and a growing aneurysm at the posterior inferior cerebellar artery (PICA), which was not a true cause of infarction. CASE PRESENTATION: A 50-year-old female presented with dizziness and posterior neck pain at our hospital (Mitaka city, Tokyo, Japan). Diffusion weighted magnetic resonance (MR) images showed cerebellar infarction in the left PICA territory and MR angiography study showed an aneurysm at the origin of the left PICA, which grew in 2 weeks. Since we considered cerebellar infarction was caused by thrombosis from the aneurysm, trapping of the PICA and occipital artery-PICA bypass was performed to prevent recurrent cerebellar infarction and rupture of the aneurysm by neurosurgeons. During the operation, dissection was observed at the distal PICA, which was diagnosed to be the true cause of cerebellar infarction. By the follow-up for 12 months at an outpatient, there was no recurrence of cerebral infarction. CLINICAL DISCUSSION: A specimen of the artery showing the findings of dissection was not obtained, and the pathological diagnosis could not be made. It would be controversial whether a surgical procedure presented here was the most optimal. CONCLUSION: This is a first reported case of growing aneurysms and cerebral infarction due to arterial dissection. Even if cerebral infarction is accompanied by growing aneurysms, arterial dissection should be included in the differential diagnoses of a cause of infarction. Posterior cervical pain can be a clue for early appropriate diagnosis in such a case.

[Preventive and Ameliorating Effects of Food Factors on Obesity-related Diseases by Regulating Inflammation].

Japan is currently a super-aging society, and lifestyle-related diseases that increase in incidence with age and the related rise in national medical expenses are major social problems. Preventive medicine and self-medication are becoming more important. Recently, various in vitro and in vivo studies have shown that food-derived natural compounds may contribute to the prevention and treatment of obesity-related diseases, such as diabetes mellitus. This report reviews our previous studies on the usefulness of the citrus flavonoid naringenin for obesity-related diseases. We showed that naringenin exerts an anti-diabetic effect by regulating inflammation pathways involving adipocytes and adipose tissue, and also showed an interaction between naringenin and anti-diabetic drugs. Because natural compounds are generally inexpensive and safe, they have the advantage of being easily applied to clinical applications. However, more detailed studies, such as clinical trials in humans, are required. Further research and scientific evidence will be required for the proper use of food factors in disease prevention and treatment.

Effects of post-exercise glucose ingestion at different solution temperatures on glycogen repletion in mice.

Carbohydrate ingestion is essential for glycogen recovery after exercise. Although studies have investigated methods for enhancement of glycogen repletion with regard to nutrients and their amounts, no studies have examined the effect of temperature of the ingested solution on glycogen recovery. Therefore, this study aimed to investigate the effect of the temperature of glucose solution ingested after exercise on glycogen recovery. Seven-week-old male ICR mice were fasted for 16 h and subjected to treadmill running exercise (20 m/min for 60 min) to decrease glycogen storage. Then, the mice were administered glucose (1.5 mg/g body weight) at three different solution temperatures: 4°C, cold solution group (Cold); 37°C, mild solution group (Mild); and 55°C, hot solution group (Hot). Our results revealed that blood glucose, plasma insulin, and muscle glycogen concentrations did not differ among the three groups. In contrast, liver glycogen concentration in the Hot group was significantly higher than that in the post-exercise and Cold groups (p < 0.05). Furthermore, portal glucose concentration was significantly higher in the Hot group than in the Cold group (p < 0.01). These observations suggest that postexercise muscle glycogen repletion occurs regardless of glucose solution temperature, and that ingesting hot glucose solution after exercise can be an effective means for liver glycogen repletion compared with cold glucose solution ingestion.

Entamoeba Chitinase is Required for Mature Round Cyst Formation.

Entamoeba histolytica, a protozoan parasite, causes amoebiasis in humans. Amoebiasis transmission is solely mediated by chitin-walled cysts, which are produced in the large intestine of humans from proliferative trophozoites by a cell differentiation process called encystation. Resistance to environmental stresses, an essential characteristic for transmission, is attributed to the cyst wall, which is constructed from chitin and several protein components, including chitinase. Chitinase may play a key role in cyst wall formation; however, this has not been confirmed. Here, to elucidate the physiological role of chitinase during Entamoeba encystation, we identified a new chitinase inhibitor, 2,6-dichloro-4-[2-(1-piperazinyl)-4-pyridinyl]-N-(1,3,5-trimethyl-1H-pyrazol-4-yl)-benzenesulfonamide, by recombinant-Entamoeba chitinase-based screening of 400 Pathogen Box chemicals. This compound dose dependently inhibited native chitinase associated with Entamoeba invadens encystation, a model for E. histolytica encystation, with an 50% inhibitory concentration (IC50) of ∼0.6 µM, which is comparable to the IC50s (0.2 to 2.5 µM) for recombinant E. histolytica and E. invadens chitinases. Furthermore, the addition of this compound to E. invadens encystation-inducing cultures increased the generation of cyst walls with an abnormal shape, the most characteristic of which was a "pot-like structure." A similar structure also appeared in standard culture, but at a far lower frequency. These results indicate that chitinase inhibition increases the number of abnormal encysting cells, thereby significantly reducing the efficiency of cyst formation. Transmission electron microscopy showed that compound-treated encysting cells formed an abnormally loose cyst wall and an unusual gap between the cyst wall and cell membrane. Hence, Entamoeba chitinase is required for the formation of mature round cysts. IMPORTANCE Amoebiasis is caused by Entamoeba histolytica infection and is transmitted by dormant Entamoeba cells or cysts. Cysts need to be tolerant to severe environmental stresses faced outside and inside a human host. To confer this resistance, Entamoeba parasites synthesize a wall structure around the cell during cyst formation. This cyst wall consists of chitin and several protein components, including chitinase. The physiological roles of these components are not fully understood. Here, to elucidate the role of chitinase during cyst formation, we identified a new chitinase inhibitor by screening a library of 400 compounds. Using this inhibitor, we showed that chitinase inhibition causes the formation of abnormal cyst walls, the most characteristic of which is a "pot-like structure." This results in decreased production of mature cysts. Chitinase is therefore required for Entamoeba to produce mature cysts for transmission to a new host.