Nonlinear Relationship Between Low Density Lipoprotein and the Probability of Diabetic Macular Edema.

Purpose: Previous studies simply linearized the relationship between low density lipoprotein (LDL) and diabetic macular edema's (DME) probability, ignoring the possibility of a nonlinear relationship between them. We aimed to investigate the nonlinear relationship between LDL and DME probability in patients with type 2 diabetes mellitus (T2DM). Patients and methods: The study recruited 431 T2DM patients who attended Guangdong Provincial People's Hospital from December 2017 to November 2018. A multivariate logistic regression model was conducted to evaluate the association between LDL and DME probability. The nonlinear relationship was identified by generalized additive model. Subgroup analyses were performed to assess the consistency of the association in different subgroups. Results: LDL was positively associated with DME probability (OR=1.60, 95% CI: 1.10~2.34, P=0.0145) after adjusting for covariates. A nonlinear relationship between LDL and DME probability was discovered, with an inflection point for LDL around 4.85 mmol/L (95% CI: 4.18~4.93, P=0.037). The effect sizes and the confidence intervals on the left and right sides of inflection point were 2.17 (1.31 to 3.58) and 0.26 (0.04 to 1.77), respectively. Subgroup analyses revealed other variables had no effect on the association between them. Conclusion: Our finding suggested LDL was positively correlated with DME probability in T2DM patients. And the relationship between LDL and DME probability was nonlinear. Our findings need to be confirmed by further causal researches.

Molecular basis for substrate transport of Mycobacterium tuberculosis ABC importer DppABCD.

The type I adenosine 5'-triphosphate (ATP)-binding cassette (ABC) transporter DppABCD is believed to be responsible for the import of exogenous heme as an iron source into the cytoplasm of the human pathogen Mycobacterium tuberculosis (Mtb). Additionally, this system is also known to be involved in the acquisition of tri- or tetra-peptides. Here, we report the cryo-electron microscopy structures of the dual-function Mtb DppABCD transporter in three forms, namely, the apo, substrate-bound, and ATP-bound states. The apo structure reveals an unexpected and previously uncharacterized assembly mode for ABC importers, where the lipoprotein DppA, a cluster C substrate-binding protein (SBP), stands upright on the translocator DppBCD primarily through its hinge region and N-lobe. These structural data, along with biochemical studies, reveal the assembly of DppABCD complex and the detailed mechanism of DppABCD-mediated transport. Together, these findings provide a molecular roadmap for understanding the transport mechanism of a cluster C SBP and its translocator.

An oligopeptide permease, OppABCD, requires an iron-sulfur cluster domain for functionality.

Oligopeptide permease, OppABCD, belongs to the type I ABC transporter family. Its role is to import oligopeptides into bacteria for nutrient uptake and to modulate the host immune response. OppABCD consists of a cluster C substrate-binding protein (SBP), OppA, membrane-spanning OppB and OppC subunits, and an ATPase, OppD, that contains two nucleotide-binding domains (NBDs). Here, using cryo-electron microscopy, we determined the high-resolution structures of Mycobacterium tuberculosis OppABCD in the resting state, oligopeptide-bound pre-translocation state, AMPPNP-bound pre-catalytic intermediate state and ATP-bound catalytic intermediate state. The structures show an assembly of a cluster C SBP with its ABC translocator and a functionally required [4Fe-4S] cluster-binding domain in OppD. Moreover, the ATP-bound OppABCD structure has an outward-occluded conformation, although no substrate was observed in the transmembrane cavity. Here, we reveal an oligopeptide recognition and translocation mechanism of OppABCD, which provides a perspective on how this and other type I ABC importers facilitate bulk substrate transfer across the lipid bilayer.

SWsnn: A Novel Simulator for Spiking Neural Networks.

Spiking neural network (SNN) simulators play an important role in neural system modeling and brain function research. They can help scientists reproduce and explore neuronal activities in brain regions, neuroscience, brain-like computing, and other fields and can also be applied to artificial intelligence, machine learning, and other fields. At present, many simulators using central processing unit (CPU) or graphics processing unit (GPU) have been developed. However, due to the randomness of connections between neurons and spiking events in SNN simulation, this causes a lot of memory access time. To alleviate this problem, we developed an SNN simulator SWsnn based on the new Sunway SW26010pro processor. The SW26010pro processor consists of six core groups, each with 16 MB of local data memory (LDM). LDM has the characteristics of high-speed read and write, which is suitable for performing simulation tasks similar to SNNs. Experimental results show that SWsnn runs faster than other mainstream GPU-based simulators when simulating a certain scale of neural network, showing a strong performance advantage. To conduct larger scale simulations, SWsnn designed a simulation computation based on a large shared model of Sunway processor and developed a multiprocessor version of SWsnn based on this mode, achieving larger scale SNN simulations.

Clinical characteristics and microbiological tests analysis of 18 patients with Talaromyces marneffei infection / 中国热带医学

@#Abstract:Objective　To investigate the clinical characteristics and early diagnostic methods of patients with Talaromyces marneffei infection, so as to reduce the mortality of patients. Methods The clinical characteristics and microbiological analysis data including fungal culture, smear examination and mass spectrometry were collected from 18 patients with Talaromyces marneffei infection in the Department of Respiratory Medicine, Department of Tuberculosis, and Department of Critical Respiratory Medicine in Fuzhou Pulmonary Hospital from January 2017 to December 2021, and descriptive analysis was conducted. Results　All the 18 patients were confirmed to be infected with Talaromyces marneffei by conventional culture and matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry (MS). The main infection sites of 18 patients with Talaromyces marneffei infection were lungs and lymph nodes, and the patients were accompanied by clinical manifestations such as cough, sputum and fever. The imaging features such as patchy shadows, mediastinal lymph node shadows and nodular shadows were common. Microbiological testing showed a statistically significant difference between smear and culture with a higher positive culture rate (χ2=13.74, P<0.05). The positive rate of blood culture in microbiological test was 60.0% (9/15), the positive rate of bronchial lavage fluid culture was 26.7% (4/15), the positive rate of sputum culture was 5.6% (1/18), one case each of pus, bone marrow, pleural fluid and cerebrospinal fluid was positive for culture and the other cases were negative, one case of sputum and one case of pus were positive for smear and the rest were negative. Colony characteristics showed that the colony morphology was mycelial phase at 25 ℃, producing red pigment, and the branching pattern of the penicillus was seen microscopically as monoverticillate or biverticillate; At 35 ℃, the yeast phase appeared at the initial stage, and then the mycelium phase changed after 5-6 days; the yeast phase was observed at 37 ℃, and yeast-like cells were seen under the microscope. All 18 patients with Talaromyces marneffei infection got better after using antifungal drugs. Compared with non-HIV patients with Talaromyces marneffei infection, leukopenia and anemia were common in HIV patients with Talaromyces marneffei infection, and the differences were statistically significant (P<0.05). 　Conclusions The infection of Talaromyces marneffei can be divided into localized type and disseminated type, which usually invade the lungs, skin, lymph nodes and other places. The main manifestations of patients are fever, cough, phlegm and other atypical symptoms. At present, the diagnosis of Talaromyces marneffei infection is mostly based on the fungal culture test, and the application of MALDI-TOF MS method can effectively shorten the diagnosis time of Talaromycosis marneffei. Clinical characteristics combined with microbiological analysis provide an objective basis for early diagnosis of patients with Talaromyces marneffei infection, and timely use of antifungal therapy can improve the prognosis of patients.