Objective: To address systemic challenges in the blood system, such as supply-demand imbalance, inefficient allocation, and inappropriate clinical use, while bridging gaps in current theories regarding the integration of social mobilization, institutional practice, and policy coordination. It sought to construct a system dynamics model spanning from macro to micro levels to analyze the blood management system holistically. Methods: Key variables were identified by a systematic literature search in both Chinese and English databases. An improved Delphi method was then employed to conduct expert consultations across different fields, leading to the selection and determination of core variable sets for each sub-model. Furthermore, by defining their logical relationships, a system dynamics model was constructed to systematically analyze the operation mechanism of the blood management system. Results: Four core sub-models were developed: 1) A macro "Dynamic Balance" model quantifying regional supply-demand equilibrium and inventory control; 2) a mobilization "Three-Layer Funnel" model analyzing how socio-cultural factors, service channels, and policy incentives influence donation behavior; 3) an institutional "Dual-Cycle Regulation" model revealing hospital blood usage is driven by both disease burden (demand cycle) and management practices (regulation cycle); and 4) an individual "Three-Layer Filter" model standardizing clinical transfusion decisions based on necessity, risk-benefit, and context. These were integrated into a "Multi-Layer Linkage and Feedback" model, elucidating bidirectional interactions among five levels: policy environment, regional supply, blood station mobilization, hospital application, and clinical decision-making. Conclusion: This study constructed a system dynamics model for blood management. By defining key variables and their logical relationships, it systematically analyzes the system′s operational mechanism. The integrated framework connects multiple levels—regional supply, voluntary donation, hospital blood use, and clinical decision-making—revealing their intrinsic linkages. Future efforts should employ systems thinking to synergistically enhance supply-side mobilization, demand-side management, systemic regulation, and decision standardization to build a safe, efficient, and sustainable blood security system.

Magnetotactic bacteria (MTB), a group of phylogenetically diverse organisms that use their unique intracellular magnetosome organelles to swim along the Earth's magnetic field, play important roles in the biogeochemical cycles of iron and sulfur. Previous studies have revealed that the bacterial actin protein MamK plays essential roles in the linear arrangement of magnetosomes in MTB cells belonging to the Proteobacteria phylum. However, the molecular mechanisms of multiple-magnetosome-chain arrangements in MTB remain largely unknown. Here, we report that the MamK filaments from the uncultivated 'Candidatus Magnetobacterium casensis' (Mcas) within the phylum Nitrospirae polymerized in the presence of ATP alone and were stable without obvious ATP hydrolysis-mediated disassembly. MamK in Mcas can convert NTP to NDP and NDP to NMP, showing the highest preference to ATP. Unlike its Magnetospirillum counterparts, which form a single magnetosome chain, or other bacterial actins such as MreB and ParM, the polymerized MamK from Mcas is independent of metal ions and nucleotides except for ATP, and is assembled into well-ordered filamentous bundles consisted of multiple filaments. Our results suggest a dynamically stable assembly of MamK from the uncultivated Nitrospirae MTB that synthesizes multiple magnetosome chains per cell. These findings further improve the current knowledge of biomineralization and organelle biogenesis in prokaryotic systems.
Actins ; chemistry ; metabolism ; Adenosine Triphosphate ; metabolism ; Bacteria ; classification ; metabolism ; Bacterial Proteins ; chemistry ; metabolism ; Magnetospirillum ; classification ; metabolism ; Nucleotides ; metabolism ; Phylogeny ; Substrate Specificity

BACKGROUNDCushing's disease (CD) presents a remarkable preponderance in female gender, and a significant minority of patients with CD presented with negative magnetic resonance imaging (MRI) findings. The aim of this study was to evaluate gender-related and MRI classification-related differences in clinical and biochemical characteristics of CD.

METHODSWe retrospectively studied 169 patients with CD, comprising 132 females and 37 males, and 33 patients had no visible adenoma on MRI.

RESULTSWe observed that male and MRI-positive patients presented with high adrenocorticotropic hormone (ACTH) values (P < 0.05). Female patients presented with higher prevalence of hirsutism and hyperpigmentation and lower prevalence of purple striae (P < 0.05). The prevalence of buffalo-hump and hypertension was greater in MRI-negative patients (P < 0.05). In addition, male patients with CD presented at a younger age compared with females (P < 0.05). Patients with fatigue and hypokalaemia presented significantly higher urinary-free cortisol, ACTH and cortisol levels compared with patients without these symptoms (P < 0.05). The prevalence of LH reduction, hyper total cholesterol (TC) and hyper low-density lipoprotein was more frequent in MRI-positive patients (P < 0.05). Hyper-TC levels and PRL reduction were more frequent in males (P < 0.05). T3, T4 and FT3 levels negatively correlated with age at diagnosis (r = -0.310, P < 0.01; r = -0.191, P < 0.05; r = -0.216, P < 0.05). T3, T4, FT3 and FT4 levels significantly negatively correlated with 8-am plasma cortisol levels (r = -0.328, P < 0.01; r = -0.195, P < 0.05; r = -0.333, P < 0.01; r = -0.180, P < 0.05). Females presented higher total protein level (P < 0.01) and lower blood urea nitrogen and serum creatinine levels (P < 0.01), compared with male patients.

CONCLUSIONSCarefulness and caution are required in all patients with CD, because of the complexity of clinical and biochemical characteristics in CD patients of different gender and MRI classification, particularly male patients and MRI-negative patients.

Adolescent ; Adult ; Aged ; Dyslipidemias ; diagnosis ; Female ; Humans ; Hypertension ; diagnosis ; Hypokalemia ; diagnosis ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Pituitary ACTH Hypersecretion ; complications ; diagnosis ; Retrospective Studies ; Sex Factors ; Young Adult