Distribution of platelet-derived growth factor-alpha receptor expressing oligodendrocyte precursor cells in the adult rat brain

BACKGROUND： Studies have demonstrated that NG2-positive glial cells in the adult rats are predominantly located in the gray and white matter of the cerebral cortex and hippocampus. Platelet-derived growth factor-a receptor （PDGF-αR） cells are a subset of oligodendrocytes, which are not as mature as NG2-positive cells. Distribution and migration of PDGF-αR-positive cells in the rat brain remain poorly understood. OBJECTIVE： Using immunohistochemical methods, the distribution of oligodendrocyte precursor cells （PDGF-αR-positive） was analyzed in the adult rat brain. DESIGN, TIME AND SETTING： Immunohistochemical study was performed at the Department of Histology and Embryology of the Third Military Medical University from September 2007 to September 2008. MATERIALS： Rabbit anti-PDGF-αR polyclonal antibody was purchased from Santa Cruz Biotechnology, USA. Streptomycin-avidin-biotin complex immunohistochemistry kit was purchased from Zhongshan Goldenbridge Biotechnology, China. METHODS： Whole brains from 5 healthy, adult, Wistar rats were collected for immunohistochemistry, and the mean value of PDGF-αR-expressing cells was quantified. The absolute values were translated to ranked data of high, moderate, and low grades （high grade： 10 positive cells; moderate grade： 5-9 cells; low grade： 〈 5 cells in a 400 × visual field）. Based on the number of cell processes and branches, as well as the number of PDGF-αR-positive cells, in different regions, the cells were classified into three categories, i.e., type Ⅰ-Ⅲ. From type I to type Ill, the number of processes gradually increased. MAIN OUTCOME MEARSURES： The number and distribution of PDGF-αR-positive cells in different brain regions of adult rats. RESULTS： PDGF-αR-positive cells were located in the forebrain and midbrain, but not in the cerebellum or brainstem. In the olfactory bulb and hippocampus, a total of 60% PDGF-αR-positive cells were type Ⅰ and these cells were not mature as others. In the cerebral cortex, olfactory system, hippocampus, and optic chiasma, where neuronal bodies aggregated, approximately 40% of the PDGF-αR-positive cells were type Ⅱ, with few type Ⅲ cells. In the white matter, corpus callosum, basal nucleus, and thalamus, PDGF-αR-positive cell density was moderate. In the olfactory bulb and hippocampus, PDGF-αR-positive cell density was high. PDGF-αR-positive cells were not observed in the cerebellum or brainstem CONCLUSION： PDGF-αR-positive cells were aggregated in the olfactory bulb and hippocampus in the adult, rat brain, but few cells were detected in the cerebellum and brainstem.

Liver Dysfunction and Its Association with the Risk of Death in COVID-19 Patients:A Prospective Cohort Study

Background and Aims:Coronavirus disease 2019(COVID-19)is a new respiratory infectious disease caused by severe acute respiratory syndrome coronavirus-2(commonly known as SARS-CoV-2)with multiple organ injuries.The aim of this study was to analyze COVID-19-associated liver dysfunction(LD),its association with the risk of death and prognosis after discharge.Methods:Three-hundred and fifty-five COVID-19 patients were recruited.Clinical data were collected from electronic medical records.LD was evaluated and its prognosis was tracked.The association between LD and the risk of death was analyzed.Results:Of the 355 COVID-19 patients,211 had mild disease,88 had severe disease,and 51 had critically ill disease.On admission,223(62.8%)patients presented with hypoproteinemia,151(42.5%)with cholestasis,and 101(28.5%)with hepatocellular injury.As expected,LD was more common in critically ill patients.By multivariate logistic regression,male sex,older age and lymphopenia were three important independent risk factors predicting LD among COVID-19 patients.Risk of death analysis showed that the fatality rate was higher in patients with hypoproteinemia than in those without hypoproteinemia(relative risk=9.471,p<0.01).Moreover,the fatality rate was higher in patients with cholestasis than those without cholestasis(relative risk=2.182,p<0.05).Follow-up observation found that more than one hepatic functional index of two-third patients remained abnormal at 14 days after discharge.Conclusions:LD at early disease stage elevates the risk of death of COVID-19 patients.COVID-19-associated LD does not recover completely by 14 days after discharge.

New perspectives on traumatic bone infections

In this paper,we review the results of previous studies and summarize the effects of various factors on the regulation of bone metabolism in traumatic bone infections.Infection-related bone destruction incorporates pathogens and iatrogenic factors in the process of bone resorption dominated by the skeletal and immune systems.The development of bone immunology has established a bridge of communication between the skeletal system and the immune system.Exploring the effects of pathogens,skeletal systems,immune systems,and antibacterials on bone repair in infectious conditions can help improve the treatment of these diseases.

Fungal periprosthetic joint infection:Rare but challenging problem

Periprosthetic joint infection (PJI) is the most difficult complication following total joint arthroplasty. Most of the etiological strains, accounting for over 98% of PJI, are bacterial species, with Staphylococcus aureus and Coagulase-negative staphylococci present in between 50% and 60% of all PJIs. Fungi, though rare, can also cause PJI in 1%—2% of cases and can be challenging to manage. The management of this uncommon but complex condition is challenging due to the absence of a consistent algorithm. Diagnosis of fungal PJI is difficult as isolation of the organisms by traditional culture may take a long time, and some of the culture-negative PJI can be caused by fungal organisms. In recent years, the introduction of next-generation sequencing has provided opportunity for isolation of the infective organisms in culture-negative PJI cases. The suggested treatment is based on consensus and includes operative and non-operative measures. Two-stage revision surgery is the most reliable surgical option for chronic PJI caused by fungi. Pharmacological therapy with antifungal agents is required for a long period of time with antibiotics and included to cover superinfections with bacterial species. The aim of this review article is to report the most up-to-date information on the diagnosis and treatment of fungal PJI with the intention of providing clear guidance to clinicians, researchers and surgeons.