BACKGROUND: Corticosteroids have been used for refractory Mycoplasma pneumoniae pneumonia and have beneficial effects. The aim of this study was to identify the biomarkers for predicting refractory M. pneumoniae pneumonia in a timely fashion to initiate steroid therapy. METHODS: This was a prospective cohort study of children with M. pneumoniae pneumonia admitted to the Children's Hospital of Fudan University from September 2012 to August 2013. Lactate dehydrogenase (LDH) and other laboratory tests, including complete blood counts, C-reactive protein, erythrocyte sedimentation rate (ESR), alanine aminotransferase, aspartate aminotransferase, ␣-hydroxybutyrate dehydrogenase (HBDH), creatine kinase, and creatine kinase MB, were performed on admission. Based on the definition of refractory M. pneumoniae pneumonia, subjects were divided into 2 groups: refractory M. pneumoniae pneumonia and usual M. pneumoniae pneumonia.The diagnostic values of laboratory findings were analyzed. RESULTS: In total, 653 subjects were enrolled, including 300 in the refractory pneumonia group and 353 in the usual pneumonia group. There was no significant difference in sex distribution between the 2 groups. The average age in the refractory M. pneumoniae pneumonia group was greater than that in the usual M. pneumoniae pneumonia group. Compared with the usual pneumonia group, the refractory pneumonia group showed significantly higher levels of C-reactive protein, serum LDH, serum HBDH, serum alanine aminotransferase, serum aspartate aminotransferase, and neutrophils and higher ESRs. Logistic regression showed that age, LDH, and ESR were the significant factors in predicting refractory M. pneumoniae pneumonia. In addition, LDH and HBDH were strongly correlated, and receiver operating characteristic curve analysis showed that the area under the curve of LDH was 0.718 with a cutoff of 379 IU/L, that of ESR was 0.683 with a cutoff of 32.5 IU/L, and that of HBDH was 0.691 with a cutoff of 259.5 IU/L. CONCLUSIONS: Serum LDH can be used as a biomarker to predict refractory M. pneumoniae pneumonia at the early stage of hospitalization.

How primates perceive objects along with their detailed features remains a mystery. This ability to make fine visual discriminations depends upon a high-acuity analysis of spatial frequency (SF) along the visual hierarchy from V1 to inferotemporal cortex. By studying the transformation of SF across macaque parafoveal V1, V2, and V4, we discovered SF-selective functional domains in V4 encoding higher SFs up to 12 cycles/°. These intermittent higher-SF-selective domains, surrounded by domains encoding lower SFs, violate the inverse relationship between SF preference and retinal eccentricity. The neural activities of higher- and lower-SF domains correspond to local and global features, respectively, of the same stimuli. Neural response latencies in high-SF domains are around 10 ms later than in low-SF domains, consistent with the coarse-to-fine nature of perception. Thus, our finding of preserved resolution from V1 into V4, separated both spatially and temporally, may serve as a connecting link for detailed object representation.

Motion perception is qualitatively invariant across different objects and forms, namely, the same motion information can be conveyed by many different physical carriers, and it requires the processing of motion signals consisting of direction, speed, and axis or trajectory of motion defined by a moving object. Compared with the representation of orientation, the cortical processing of these different motion signals within the early ventral visual pathway of the primate remains poorly understood. Using drifting full-field noise stimuli and intrinsic optical imaging, along with cytochrome-oxidase staining, we found that the orientation domains in macaque V1, V2, and V4 that processed orientation signals also served to process motion signals associated with the axis and speed of motion. In contrast, direction domains within the thick stripes of V2 demonstrated preferences that were independent of motion speed. The population responses encoding the orientation and motion axis could be precisely reproduced by a spatiotemporal energy model. Thus, our observation of orientation domains with dual functions in V1, V2, and V4 directly support the notion that the linear representation of the temporal series of retinotopic activations may serve as another motion processing strategy in primate ventral visual pathway, contributing directly to fine form and motion analysis. Our findings further reveal that different types of motion information are differentially processed in parallel and segregated compartments within primate early visual cortices, before these motion features are fully combined in high-tier visual areas.