A survey of a COVID-19 cluster of charter flight importation

OBJECTIVES

Although a number of cases of importation with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection have been reported, there are still no data available concerning the characteristics in the coronavirus disease 2019 (COVID-19) cluster of charter flight importation. Here, we provide an analysis of COVID-19 cases and their close contacts who worked for the same company on a project in Karbala, Iraq, and returned back to Chengdu, China, by a charter flight.

METHODS

The data of imported COVID-19 cases and their close contacts were obtained from National Notifiable Disease Report System of Chinese Center for Disease Control and Prevention and field epidemiological investigation reports by Centers for Disease Control and Prevention (CDCs) in Chengdu. The information of general characteristics and laboratory findings of this cluster were collected and summarized.

RESULTS

One hundred and six (66.67%) of 159 charter flight passengers tested positive for COVID-19 before entry. Through treatment, all 159 people tested negative and meet the requirements of taking flights bound for China before boarding. However, there has been still 36 (22.64%) of them tested positive after entry. The median time from entry to confirmation was 1.0 day (Interquartile Range (IQR): 0-4.3). The Cycle threshold value (Ct value) of 36 patients' positive samples are all above 30 and most values are above 35.

CONCLUSIONS

In conclusion, there is still a risk that a number of COVID-19 cases can be imported through charter flight. However, the infectivity of confirmed patients of the charter flight was considered to be low.

A genome-wide DNA methylation analysis in peripheral blood from patients identifies risk loci associated with Graves' orbitopathy

OBJECTIVE

Graves' orbitopathy (GO) is an inflammatory orbital disease of autoimmune origin with the potential to cause severe functional and psychosocial effects. The pathogenesis has not been fully elucidated. We investigated whether DNA methylation was associated with GO incidence in Chinese patients.

MATERIALS AND METHODS

Six GO patients and six age-matched controls were recruited, and genome-wide DNA methylation patterns were analyzed in their peripheral blood. t tests were performed to determine differential methylated sites in genomic regions and the univariable logistic regression analyses was performed to evaluate their risk with GO incidence. Cluster analysis and principal component analysis (PCA) were performed to determine the effects of the extracted differentially methylated sites.

RESULTS

One hundred and forty-eight differentially methylated sites were identified, including CD14 (fold change = 4.31, p = 0.005), IL17RE (fold change = 2.128, p = 0.005), and DRD4 (fold change = 0.25, p = 0.004), and were supported by cluster and PCA analyses. Univariable logistic regression analyses showed that the methylation patterns at 12 loci were associated with GO incidence. The relative risk per 1% decrease in methylation at ZCCHC6 and GLI3 was 0.15 (95% CI 0.03-0.91; p = 0.039) and 0.65 (95% CI 0.42-0.98; p = 0.042), respectively. Pearson correlation analyses demonstrated that methylation levels at IL17RE were positively associated with Clinical Activity Score (CAS) (r = 0.967, p < 0.05).

CONCLUSIONS

Our results demonstrate that differential methylation levels at analyzed sites (genes) may be risk markers of GO. DNA methylation analysis could provide new insights into understanding the disease and provide new treatment strategies for GO in Chinese patients.

A porous sodium polyacrylate-grafted chitosan xerogel for severe hemorrhage control synthesized from one-pot reaction

In this study, we fabricated a SPA-co-CTS sponge and demonstrated a fast and powerful hemostatic effect bothin vitroandin vivo, which was a promising first-aid device for severe hemorrhage control.

Molecular characterization and phylogenetic analysis of porcine epidemic diarrhea virus samples obtained from farms in Gansu, China

Porcine epidemic diarrhea poses significant sanitation problems in the porcine industry, and has negatively affected the economy in recent years. In this study, 48 fecal specimens were collected from piglets from four intensive swine farms located in the Gansu Province of China. The molecular diversity and phylogenetic relationships between porcine epidemic diarrhea viruses (PEDV) prevalent in Gansu were probed, and the resultant proteins were characterized. Sequence analysis of the spike protein (S) genes showed that each specimen had unique characteristics, and that the PEDV1/S/4 strain could be differentiated from the others via a unique mutation of the S gene. The phylogeny of S glycoprotein showed that all strains were clustered into two major groups. The four Gansu PEDV field strains were characterized into different groups; this finding was consistent with the results of the protein characterization prediction. This analysis additionally revealed the unique characteristics of each specimen. The results of this study could be used to elucidate the prevalence of PEDV and contribute to the prevention of PEDV in Gansu.

[Application of vacuum sealing drainage in the treatment of severe necrotizing fasciitis in extremities of patients]

OBJECTIVE

To study the application of VSD in the treatment of severe necrotizing fasciitis in extremities of patients.

METHODS

Eight patients, suffering from severe necrotizing fasciitis, who had been traditionally treated with iodophor-soaked gauze for 21 to 365 days in other hospitals, were transferred to our institute because of the nonhealing wounds and systemic toxic symptoms induced by infection, from January 2011 to August 2013. After admission, surgical debridement was performed timely, and the necrotic tissue was collected during the operation for pathological observation after HE staining. After the operation, VSD was started with negative pressure ranging from -100 to -80 kPa, and the furacilin solution (0.2 g/L) and oxygen (2 L/min) were continuously infused into the wound during the treatment. Surgical debridement was performed repeatedly according to the wound condition followed by change of VSD dressings to continue VSD treatment. The wounds were closed by suturing or with autologous skin grafts after being covered by fresh granulation tissue. The times of surgical debridement, times of change of VSD materials, wound healing status, and length of stay in our institute were recorded. All patients were followed up for a long time. Results HE staining showed that there were diffuse necrotic adipose and fibrous connective tissues in the necrotic tissue, and the normal tissue structure disappeared accompanied by significant infiltration of inflammatory cells. The number of surgical debridement was 2 to 10 (3.9 +/- 2.8) times. The number of VSD materials change was 2 to 10 (4.0 +/- 2.9) times. Wounds were closed by suturing and healed in two patients; wounds in the other six patients were partially sutured, their residual wounds were healed by autologous skin grafting. The length of stay in our institute was 20 to 49 (33 +/- 10) days. All patients were discharged after recovery. Patients were followed up for 2 to 24 months, and their wounds were found to be in good condition without ulceration or recurrence.

CONCLUSIONS

VSD can effectively remove the necrotic tissues and exudates from the fascial spaces and promote proliferation of granulation tissue. Therefore it serves as an effective approach to the treatment of severe necrotizing fasciitis in extremities.

Toward surface quantification of liver fibrosis progression

Monitoring liver fibrosis progression by liver biopsy is important for certain treatment decisions, but repeated biopsy is invasive. We envision redefinition or elimination of liver biopsy with surface scanning of the liver with minimally invasive optical methods. This would be possible only if the information contained on or near liver surfaces accurately reflects the liver fibrosis progression in the liver interior. In our study, we acquired the second-harmonic generation and two-photon excitation fluorescence microscopy images of liver tissues from bile duct-ligated rat model of liver fibrosis. We extracted morphology-based features, such as total collagen, collagen in bile duct areas, bile duct proliferation, and areas occupied by remnant hepatocytes, and defined the capsule and subcapsular regions on the liver surface based on image analysis of features. We discovered a strong correlation between the liver fibrosis progression on the anterior surface and interior in both liver lobes, where biopsy is typically obtained. The posterior surface exhibits less correlation with the rest of the liver. Therefore, scanning the anterior liver surface would obtain similar information to that obtained from biopsy for monitoring liver fibrosis progression.

Laminar-flow immediate-overlay hepatocyte sandwich perfusion system for drug hepatotoxicity testing

Drug hepatotoxicity testing requires in vitro hepatocyte culture to maintain the long-term and stable liver specific functions. We developed a drug testing platform based on laminar-flow immediate-overlay hepatocyte sandwich perfusion culture. The immediate-overlay sandwich (collagen-coated porous polymeric membrane as top overlay) protects the cells and integrity of the top collagen matrix from the impact of flow. A bioreactor was designed that allowed proper control of shear stress and mass transfer. The culture parameters such as the optimal perfusion initiation time and flow rate were systematically and mechanistically determined. The optimized system could re-establish hepatocyte polarity to support biliary excretion and to maintain other liver specific functions, such as the biotransformation enzyme activities, for two weeks that extended the usable in vitro hepatocyte-based drug testing window. When the perfusion cultured hepatocytes from days 7 or 14 were used for drug testing, the APAP-induced hepatotoxicity measurements were more sensitive and consistent over time than the static culture control, enabling further exploitations in large-scale drug testing applications.

Ultrastructural cell response to tension stress during mandibular distraction osteogenesis

The response of cells in the distraction gap during mandibular distraction osteogenesis was recorded by transmission electronic microscopy. We distracted the mandible on both sides in eight adult goats. Two animals were killed at 8, 16, 32, and 48 days, respectively, after activation of the device. The specimens were harvested and processed for histological and ultrastructural examination. The results showed that the cells and newly-formed extracellular matrix (ECM) were aligned with the tension vector. In the early stage of distraction osteogenesis, cells in the distraction gap were of the active proliferative phenotype. They then differentiated into fibroblast-like cells and osteoblasts, showing ultrastructural characteristics of the active synthetic and secretory phenotypes. Newly-formed collagen, bone canaliculi, and mineralisation of the ECM were clearly evident during distraction osteogenesis. Our results show that at the ultrastructural level cell proliferation is activated by tension and stress during the early stages, and synthetic and secretory function stimulated during the later stages of mandibular distraction osteogenesis.