ABSTRACT
Bayesian Dynamic Borrowing (BDB) designs are being increasingly used in clinical drug development. These methods offer a mathematically rigorous and robust approach to increase efficiency and strengthen evidence by integrating existing trial data into a new clinical trial. The regulatory acceptability of BDB is evolving and varies between and within regulatory agencies. This paper describes how BDB can be used to design a new randomised clinical trial including external data to supplement the planned sample size and discusses key considerations related to data re-use and BDB in drug development programs. A case-study illustrating the planning and evaluation of a BDB approach to support registration of a new medicine with the Center for Drug Evaluation in China will be presented. Key steps and considerations for the use of BDB will be discussed and evaluated, including how to decide whether it is appropriate to borrow external data, which external data can be re-used, the weight to put on the external data and how to decide if the new study has successfully demonstrated treatment benefit.
Subject(s)
Research Design , Bayes Theorem , Sample Size , Drug EvaluationABSTRACT
Lipoleiomyoma is a type of tumor usually found in the uterine corpus. The pathophysiology is unclear; however, it is commonly seen in obese perimenopausal and postmenopausal women. While intrauterine lipoleiomyoma may be surveilled, there is less information about the management of extrauterine lipoleiomyoma, especially significantly large tumors. This is a case involving a 51-year-old female who was incidentally found to have a 23-cm extrauterine lipoleiomyoma emanating from the peritoneum between uterosacral ligaments. She underwent hand-assisted laparoscopic removal of an intra-abdominal tumor, which was found to be an extrauterine lipoleiomyoma. Six months later, she was found to have a recurrent mass on a follow-up computed tomography (CT) of the abdomen and pelvis. She underwent a robotic-assisted total abdominal hysterectomy, bilateral salpingo-oophorectomy, and removal of the recurrent tumor. While the mass is benign in nature, the mass effect that it may cause prompts a discussion about the best course of management and an investigation into recurrence rates, specifically in similar extrauterine presentations.
ABSTRACT
In this study, a model of ischemic stroke by surgical proximal middle cerebral artery (MCA) occlusion was developed on 10 beagle dogs. The advantages of this model are the transtemporal approach and a minimally invasive surgical procedure. Dogs were randomly assigned to two groups: sham-operated (proximal MCA exposure without occlusion) and experimental (permanent proximal MCA occlusion) groups. Different evaluation methods were used to assess the consequences of MCA occlusion in dogs, including neurobehavioral tests, MRI, and immunohistochemical staining. Clear signs of cerebral infarction associated with the region supplied by MCA were confirmed and the model showed good repeatability and consistency. The model can serve as an appropriate large animal model to improve the translation of stroke therapeutics research from the laboratory to the clinical practice.
Subject(s)
Middle Cerebral Artery , Stroke , Animals , Dogs , Disease Models, Animal , Infarction, Middle Cerebral Artery/diagnostic imaging , Infarction, Middle Cerebral Artery/surgery , Magnetic Resonance Imaging , Middle Cerebral Artery/diagnostic imaging , Middle Cerebral Artery/surgery , Stroke/diagnostic imaging , Stroke/surgeryABSTRACT
To investigate the active components/ingredients of Pudilan Xiaoyan Oral Liquid based on the network pharmacology technology, and analyze the network data of its potential targets and mechanisms. The active ingredient screening, protein interaction analysis and pathway annotation were used to further optimize its active components and potential targets, and clarify the pharmacodynamic substance basis and mechanism of Pudilan Xiaoyan Oral Liquid. Through this technique, we screened out 41 active ingredients in Pudilan Xiaoyan Oral Liquid, mainly including 16 alkaloid components, 13 organic acid components, 11 flavonoid components and 1 coumarin component such as chicoric acid, chlorogenic acid, oroxindin, rutin, corynoline, and esculetin. In addition, 6 targets for parotitis, 48 targets for tonsillitis, and 22 targets for pharyngitis were screened. A total of 22 disease signaling pathways are involved, including 4 pathways closely related to inflammation. The IL-17 signaling pathway had the highest D(degree) value and may be most closely related to inflammatory diseases. Through network data excavating, we initially explored the main active components/ingredients of Pudilan Xiaoyan Oral Liquid, clarified the pharmacodynamic basis of Pudilan Xiaoyan Oral Liquid treatment-related diseases and its key mechanism of action in this study, hoping to provide a theoretical basis for clinical research, and at the same time, lay the foundation for deep research and promotion of Pudilan Xiaoyan Oral Liquid product.
Subject(s)
Drugs, Chinese Herbal , Pharyngitis , Chlorogenic Acid , Drugs, Chinese Herbal/pharmacology , Flavonoids , HumansABSTRACT
The susceptibility of newly expressed proteins to digestion by gastrointestinal proteases (e.g., pepsin) has long been regarded as one of the important endpoints in the weight-of-evidence (WOE) approach to assess the allergenic risk of genetically modified (GM) crops. The European Food Safety Authority (EFSA) has suggested that current digestion study protocols used for this assessment should be modified to more accurately reflect the diverse physiological conditions encountered in human populations and that the post-digestion analysis should include analytical methods to detect small peptide digestion products.The susceptibility of two allergens (beta-lactoglobin (ß-Lg) and alpha-lactalbumin (α-La)) and two non-allergens (hemoglobin (Hb) and phosphofructokinase (PFK)) to proteolytic degradation was investigated under two pepsin digestion conditions (optimal pepsin digestion condition: pH 1.2, 10 U pepsin/µg test protein; sub-optimal pepsin digestion condition: pH 5.0, 1 U pepsin/10 mg test protein), followed by 34.5 U trypsin/mg test protein and 0.4 U chymotrypsin/mg test protein digestion in the absence or presence of bile salts. All samples were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) in conjunction with Coomassie Blue staining and, in parallel, liquid chromatography tandem mass spectrometry (LC-MS) detection. The results provide following insights: 1) LC-MS methodology does provide the detection of small peptides; 2) Peptides are detected in both allergens and non-allergens from all digestion conditions; 3) No clear differences among the peptides detected from allergen and non-allergens; 4) The differences observed in SDS-PAGE between the optimal and sub-optimal pepsin digestion conditions are expected and align with kinetics and properties of the specific enzymes; 5) The new methodology with new digestion conditions and LC-MS detection does not provide any differentiating information for prediction whether a protein is an allergen. The classic pepsin resistance assay remains the most useful assessment of the potential exposure of an intact newly expressed protein as part of product safety assessment within a WOE approach.
Subject(s)
Allergens/chemistry , Food Analysis/methods , Peptides/chemistry , Proteolysis , Allergens/metabolism , Animals , Chromatography, Liquid/methods , Food Safety , Hemoglobins/chemistry , Hemoglobins/metabolism , Lactalbumin/chemistry , Lactalbumin/metabolism , Lactoglobulins/chemistry , Lactoglobulins/metabolism , Peptides/metabolism , Phosphofructokinases/chemistry , Phosphofructokinases/metabolism , Swine , Tandem Mass Spectrometry/methods , Trypsin/metabolismABSTRACT
This study provides a comprehensive description of chondrocranial development before, during and after larval metamorphosis in the tongue sole Cynoglossus semilaevis, a commercially valuable flatfish in China. Samples were collected at regular intervals ranging from 1 to 23 days post hatching (dph). Based on observations of cleared and double-stained specimens and images from sections stained with safranin O-fast green, major morphological events during early development were described. No cartilaginous structure was visible at hatching. From 2 dph onwards, cartilaginous structures such as the trabecular bar and some elements of the mandibular, hyoid and branchial arches appeared. At this time also, cartilaginous structures of the neurocranium started to form. Hypertrophic chondrocytes could be observed in many splanchnocranium elements at 5 dph. The start of ossification was indicated by alizarin red stain visible at 14 dph. At 17 dph, most of the cartilaginous skeleton was ossified. Soon after, the right eye started to migrate and pass through a slit beneath the dorsal-fin base and above the skull. Metamorphosis was complete at 20 dph, at which time the dorsal-fin base cartilage extended onto the anterior region of the head. Meanwhile, extremities of the hyoid and branchial arch elements remained cartilaginous. At 23 dph, endochondral ossification of the splanchnocranium was nearly complete. Unlike previous observations of other Pleuronectiformes, our study indicates that endochondral ossification of C. semilaevis skull cartilage occurs before metamorphosis.
Subject(s)
Cartilage/growth & development , Flounder/growth & development , Metamorphosis, Biological , Skull/growth & development , Animals , Branchial Region/growth & development , China , Flatfishes , Flounder/anatomy & histology , Mandible/growth & development , OsteogenesisABSTRACT
Decades of developmental research have capitalized on the fact that infants are surprised (i.e., look longer) at some events but not others. Differences in looking time have been considered to be a reflection of perceptual discrimination, or a reaction toward witnessing a violation of prior expectations. Here, we provide an overview of a new perspective on infant surprise that examines the underlying cognitive processes that drive this response. We suggest that looking time may reflect sophisticated statistical inference, and we review empirical evidence and computational modeling results from several recent studies to support this conjecture (Kidd, Piantadosi, & Aslin, ; Piantadosi, Kidd, & Aslin, ; Sim, Griffiths, & Xu, ; Sim & Xu, ; Téglás et al., ). We also discuss how our view relates to other new developmental research on surprise and learning (Stahl & Feigenson, , ) and outline some suggestions for future research.
Subject(s)
Child Development/physiology , Cognition/physiology , Fixation, Ocular/physiology , Thinking/physiology , Visual Perception/physiology , Humans , InfantABSTRACT
AIM: To explore the better efficacy of targeted folic acid (FA)-Pluronic 85-poly(lactide-co-glycolide) (FA-P85-PLGA) polymersome in oral insulin delivery. MATERIALS & METHODS: The cytotoxicity of the polymers, in vitro qualitative and quantitative cellular uptake and the internalization mechanism of insulin-loaded FA-P85-PLGA and PLGA-P85-PLGA polymersomes were studied with the human colon adenocarcinoma cells (Caco-2 cells). Their pharmacodynamics and pharmacokinetics properties were also studied with diabetic rats. RESULTS & CONCLUSION: Polymersomes have shown good biocompatibility. Polymersomes are mainly localized within the cytoplasm of Caco-2 cells from fluorescence microscopy images. FA-P85-PLGA exhibited higher cellular uptake than PLGA-P85-PLGA polymersomes and free fluorescein isothiocyanate-labeled insulin (FITC-insulin) did. The uptake process of targeted polymersomes included clathrin- and caveolae-mediated endocytosis, macropinocytosis and the folate receptor-mediated endocytosis. Insulin-loaded FA-P85-PLGA showed better hypoglycemic effects than insulin-loaded PLGA-P85-PLGA.
Subject(s)
Diabetes Mellitus, Experimental/drug therapy , Folic Acid/pharmacology , Insulin/pharmacology , Polymers/pharmacology , Administration, Oral , Animals , Caco-2 Cells , Cell Proliferation , Diabetes Mellitus, Experimental/metabolism , Diabetes Mellitus, Experimental/pathology , Fluorescein-5-isothiocyanate/chemistry , Folic Acid/chemistry , Humans , Insulin/chemistry , Lactic Acid/chemistry , Polyglactin 910/administration & dosage , Polyglactin 910/chemistry , Polylactic Acid-Polyglycolic Acid Copolymer/chemistry , Polymers/chemistry , RatsABSTRACT
The expression of the CP4 EPSPS protein in genetically engineered (GE) soybean confers tolerance to the Roundup® family of agricultural herbicides. This study evaluated the variability of CP4 EPSPS expression using an enzyme-linked immunosorbent assay in soybean tissues collected across diverse germplasm and 74 different environments in Argentina, Brazil and the USA. Evaluated material included single and combined (stacked) trait products with other GE traits in entries with cp4 epsps gene at one or two loci. The highest level of CP4 EPSPS was observed in leaf tissues, intermediate in forage and seed, and lowest in root tissues. Varieties with two loci had approximately twice the level of CP4 EPSPS expression compared to one locus entries. Variable and non-directional level of CP4 EPSPS was observed with other factors like genetic background, trait stacking, growing region or season. The maximum and average CP4 EPSPS expression levels in seed provided large margins of exposure (MOE of approximately 4000 and 11,000, respectively), mitigating concerns over exposure to this protein in food and feed from soybean varieties tolerant to Roundup® herbicides.
Subject(s)
3-Phosphoshikimate 1-Carboxyvinyltransferase/metabolism , Agrobacterium/enzymology , Drug Tolerance , Glycine max/enzymology , Plants, Genetically Modified/enzymology , 3-Phosphoshikimate 1-Carboxyvinyltransferase/genetics , Glycine/analogs & derivatives , Glycine/pharmacology , Herbicides/pharmacology , Plants, Genetically Modified/drug effects , Plants, Genetically Modified/growth & development , Glycine max/classification , Glycine max/drug effects , Glycine max/growth & development , GlyphosateABSTRACT
Looking time experiments based on the violation-of-expectation (VOE) method have consistently demonstrated that infants look longer when their expectations are violated. However, it remains an open question whether similar effects will be observed in infants' approach behaviours. Specifically, do infants selectively approach and explore sources that violate their expectations? In this study, we address this question by examining how infants' looking times are related to their approach and exploration behaviours. Using a traditional VOE method and a crawling paradigm, we demonstrate a strong correspondence between looking time and approach behaviours, which indicates that 13-month-old infants preferentially explore sources of unexpected events. Such spontaneous exploration may provide learning opportunities and allow infants to play an active role in driving their own development. Statement of contribution What is already known on this subject? Infants look longer when their expectations are violated. There is some evidence that infants also preferentially explore objects that violate their 'core' physical expectations. What the present study adds? There is a clear correspondence between infants' looking behaviour and their approach behaviour. Expectancy violations involving non-core knowledge can similarly influence infants' exploration.
Subject(s)
Child Development/physiology , Exploratory Behavior/physiology , Infant Behavior/physiology , Female , Humans , Infant , MaleABSTRACT
Cyclophilins have diverse functions that may affect the course of central nervous system (CNS) inflammatory disorders. Anti-inflammatory and neuroprotective mechanisms may be targeted by inhibition of cyclophilin A-dependent and cyclophilin D-dependent functions, respectively. We tested the effect of cyclophilin inhibition on CNS inflammation by administering N-methyl-4-isoleucine-cyclosporin (NIM811) to mice undergoing experimental allergic encephalomyelitis (EAE). Treatment with NIM811 resulted in significant reduction of EAE clinical severity. Analysis of mitochondrial calcium retention capacity and the course of EAE in cyclophilin D knockout mice indicated that the effect of NIM811 on EAE was not entirely cyclophilin D-dependent. NIM811-treated EAE animals showed reduction in interleukin-2 expression and reduction in CNS inflammatory infiltrates. These results indicate that anti-inflammatory rather than neuroprotective mechanisms associated with cyclophilins are likely involved in the mechanism of NIM811 in EAE.
Subject(s)
Cyclosporine/therapeutic use , Encephalomyelitis, Autoimmune, Experimental/drug therapy , Immunosuppressive Agents/therapeutic use , Animals , Brain/metabolism , Brain/ultrastructure , Calcineurin/metabolism , Calcium/metabolism , Peptidyl-Prolyl Isomerase F , Cyclophilins/deficiency , Cyclophilins/genetics , Cyclosporine/metabolism , Cyclosporine/pharmacology , Cytokines/genetics , Cytokines/metabolism , Encephalomyelitis, Autoimmune, Experimental/chemically induced , Encephalomyelitis, Autoimmune, Experimental/pathology , Gene Expression Regulation/drug effects , Gene Expression Regulation/genetics , Immunosuppressive Agents/pharmacology , Leukocytes/drug effects , Leukocytes/metabolism , Macrophages/drug effects , Macrophages/metabolism , Mice , Mice, Inbred C57BL , Mice, Knockout , Microglia/drug effects , Microglia/metabolism , Mitochondria/drug effects , Mitochondria/metabolism , Myelin-Oligodendrocyte Glycoprotein/immunology , Myelin-Oligodendrocyte Glycoprotein/toxicity , Peptide Fragments/immunology , Peptide Fragments/toxicity , Spleen/metabolism , Spleen/ultrastructure , Time FactorsABSTRACT
Constructivist views of cognitive development often converge on 2 key points: (a) the child's goal is to build large conceptual structures for understanding the world, and (b) the child plays an active role in developing these structures. While previous research has demonstrated that young children show a precocious capacity for concept and theory building when they are provided with helpful data within training settings, and that they explore their environment in ways that may promote learning, it remains an open question whether young children are able to build larger conceptual structures using self-generated evidence, a form of active learning. In the current study, we examined whether children can learn high-order generalizations (which form the basis for larger conceptual structures) through free play, and whether they can do so as effectively as when provided with relevant data. Results with 2- and 3-year-old children over 4 experiments indicate robust learning through free play, and generalization performance was comparable between free play and didactic conditions. Therefore, young children's self-directed learning supports the development of higher-order generalizations, laying the foundation for building larger conceptual structures and intuitive theories. (PsycINFO Database Record
Subject(s)
Concept Formation , Generalization, Psychological , Play and Playthings/psychology , Child, Preschool , Female , Humans , Logistic Models , Male , Models, Psychological , Motivation , Psychological Tests , Psychology, ChildABSTRACT
The susceptibility of a dietary protein to proteolytic degradation by digestive enzymes, such as gastric pepsin, provides information on the likelihood of systemic exposure to a structurally intact and biologically active macromolecule, thus informing on the safety of proteins for human and animal consumption. Therefore, the purpose of standardized in vitro degradation studies that are performed during protein safety assessments is to distinguish whether proteins of interest are susceptible or resistant to pepsin degradation via a study design that enables study-to-study comparison. Attempting to assess pepsin degradation under a wide-range of possible physiological conditions poses a problem because of the lack of robust and consistent data collected under a large-range of sub-optimal conditions, which undermines the needs to harmonize in vitro degradation conditions. This report systematically compares the effects of pH, incubation time, and pepsin-to-substrate protein ratio on the relative degradation of five dietary proteins: three pepsin susceptible proteins [ribulose 1,5-bisphosphate carboxylase-oxygenase (Rubisco), horseradish peroxidase (HRP), hemoglobin (Hb)], and two pepsin resistant proteins [lipid transfer protein (LTP) and soybean trypsin inhibitor (STI)]. The results indicate that proteins susceptible to pepsin degradation are readily distinguishable from pepsin-resistant proteins when the reaction conditions are within the well-characterized optima for pepsin. The current standardized in vitro pepsin resistant assay with low pH and high pepsin-to-substrate ratio fits this purpose. Using non-optimal pH and/or pepsin-to-substrate protein ratios resulted in susceptible proteins no longer being reliably degraded by this stomach enzyme, which compromises the ability of this in vitro assay to distinguish between resistant and susceptible proteins and, therefore, no longer providing useful data to an overall weight-of-evidence approach to assessing safety of proteins.
Subject(s)
Dietary Proteins/chemistry , Food Safety , Pepsin A/chemistry , Dietary Proteins/immunology , Hydrogen-Ion Concentration , Time FactorsABSTRACT
The purpose of this hospital-based case-control study was to assess whether the interleukin (IL)-17 rs2275913 genetic variation can influence susceptibility to gastric cancer. Samples from a total of 202 gastric cancer patients and 237 controls were collected from the Linyi People's Hospital between March 2013 and March 2015. The IL-17 rs2275913 gene polymorphism was identified by polymerase chain reaction and restriction fragment length polymorphism. When compared with control subjects, gastric cancer patients were older in age (OR = 3.89, 95%CI = 2.55-5.95), male (OR = 2.08, 95%CI = 1.39-3.10), had a habit of alcohol consumption (OR = 1.71, 95%CI = 1.15-2.55), and were more likely to be infected with Helicobacter pylori (OR = 2.76, 95%CI = 1.83-4.16). We observed that the AA genotype of the IL-17 rs2275913 polymorphism resulted in a 2.32-fold risk of gastric cancer compared to the GG genotype (OR = 2.32, 95%CI = 1.20-4.54; P = 0.01). The AG combined with AA genotype of the IL-17 rs2275913 polymorphism had more risk of developing gastric cancer than the GG genotype (OR = 1.50, 95%CI = 1.01-2.23; P = 0.04). Moreover, the AA genotype of the IL-17 rs2275913 polymorphism was correlated with a higher risk of developing gastric cancer than the GG and AG genotypes combined (OR = 2.01, 95%CI = 1.08-3.79; P = 0.02). In conclusion, the results of our study suggest that the IL-17 rs2275913 polymorphism could contribute to the risk of gastric cancer.
Subject(s)
Genetic Association Studies , Helicobacter Infections/genetics , Interleukin-17/genetics , Stomach Neoplasms/genetics , Adult , Aged , Asian People , Female , Genetic Predisposition to Disease , Helicobacter Infections/microbiology , Helicobacter Infections/pathology , Helicobacter pylori/pathogenicity , Humans , Male , Middle Aged , Polymorphism, Single Nucleotide , Risk Factors , Stomach Neoplasms/microbiology , Stomach Neoplasms/pathologyABSTRACT
Empoasca onukii Matsuda is a worldwide pest that causes great economic loss in tea growing areas and is significantly affected by temperatures. Heat shock protein (Hsp) genes are important in insects' response to temperature stress. In this study, two full-length Hsp genes, Eohsp90 and Eohsp70, were cloned from E. onukii using rapid amplification of complementary DNA ends. The open reading frames of Eohsp90 and Eohsp70 were 2,172 bp and 2,016 bp in length, respectively. Their deduced amino acid sequences of Eohsp90 and Eohsp70 showed high homology with other species. Subsequently, the transcriptional expression of Eohsp90 and Eohsp70 in E. onukii adults exposed to various temperatures (-5, 0, 10, 15, 20, 25, 30, 35, 38, 41 and 44°C) for 1 h, and at extreme temperatures (0°C and 41°C) for various time duration (0, 20, 40, 60, 80, 100, and 120 min) were investigated via real-time quantitative polymerase chain reaction. The relative expression levels of both Eohsp90 and Eohsp70 in E. onukii adults were upregulated as the temperature rises or falls over time, except in the -5°C or 44°C temperature groups. Moreover, the expression level in the temperature elevated groups was higher than that of the lower temperature groups. In addition, the Eohsp70 generally demonstrated a higher transcriptional level than Eohsp90, and both genes had a higher expression profile in female adults compared with the males. The expression profiles indicated that Eohsp90 and Eohsp70 may play important roles in E. onukii adult responses to ecologically relevant environmental temperature threat.
Subject(s)
HSP70 Heat-Shock Proteins/metabolism , HSP90 Heat-Shock Proteins/metabolism , Hemiptera/metabolism , Insect Proteins/metabolism , Stress, Physiological , Amino Acid Sequence , Animals , Base Sequence , Female , Gene Expression Profiling , HSP70 Heat-Shock Proteins/genetics , HSP90 Heat-Shock Proteins/genetics , Hemiptera/genetics , Insect Proteins/genetics , Male , Molecular Sequence Data , Sequence Analysis, DNA , Sequence Homology, Amino Acid , Temperature , Time FactorsABSTRACT
We present the first experimental result of direct delineation of the nuclei of living rat bladder epithelium with ultrahigh-resolution optical coherence tomography (uOCT). We demonstrate that the cellular details embedded in the speckle noise in a uOCT image can be uncovered by time-lapse frame averaging that takes advantage of the micromotion in living biological tissue. The uOCT measurement of the nuclear size (7.9+/-1.4 microm) closely matches the histological evaluation (7.2+/-0.8 microm). Unlike optical coherence microscopy (OCM), which requires a sophisticated high-NA microscopic objective, this approach uses a commercial-grade single achromatic lens (f/10 mm, NA/0.25) and provides a cross-sectional image over 0.6 mm of depth without focus tracking, thus holding great promise of endoscopic optical biopsy for diagnosis and grading of flat epithelial cancer such as carcinoma in situ in vivo.
Subject(s)
Cell Nucleus/ultrastructure , Epithelium/ultrastructure , Image Enhancement/methods , Microscopy, Video/methods , Subtraction Technique , Tomography, Optical Coherence/methods , Animals , Image Interpretation, Computer-Assisted/methods , Rats , Urinary Bladder/ultrastructureABSTRACT
To describe the suppressive effect of sera from patients with aplastic anemia (AA) on heamatopoietic progenitor cells and explore further the features of serum inhibitor, we first examined the inhibiting activity of the serum on the colony formation of burst-forming units of erythrocyte (BFU-E) and colony-forming units of granulocyte/macrophage (CFU-GM). The potent inhibiting activity was demonstrated in six of 20 patients. Five of the six patients were severe AA (SAA). The suppressive effect did not change after elimination of monocyles and lymphocytes from target MNC. The haematopoietic inhibitory activity of sera from three of the six patients was almost totally neutralized by the MoAb against gamma-IFN. All these three patients were SAA. These data suggest that inhibitor of haematopoietic progenitor cells is present in most of SAA patients. In some patients, the inhibitor was gamma-IFN, which play an important role in the pathogenesis of SAA.