Evaluating the Demand for Nucleic Acid Testing in Different Scenarios of COVID-19 Transmission: A Simulation Study.

INTRODUCTION: The 2019 novel coronavirus (COVID-19) has been recognized as the most severe human infectious disease pandemic in the past century. To enhance our ability to control potential infectious diseases in the future, this study simulated the influence of nucleic acid testing on the transmission of COVID-19 across varied scenarios. Additionally, it assessed the demand for nucleic acid testing under different circumstances, aiming to furnish a decision-making foundation for the implementation of nucleic acid screening measures, the provision of emergency materials, and the allocation of human resources. METHODS: Considering the transmission dynamics of COVID-19 and the preventive measures implemented by countries, we explored three distinct levels of epidemic intensity: community transmission, outbreak, and sporadic cases. Integrating the theory of scenario analysis, we formulated six hypothetical epidemic scenarios, each corresponding to possible occurrences during different phases of the pandemic. We developed an improved SEIR model, validated its accuracy using real-world data, and conducted a comprehensive analysis and prediction of COVID-19 infections under these six scenarios. Simultaneously, we assessed the testing resource requirements associated with each scenario. RESULTS: We compared the predicted number of infections simulated by the modified SEIR model with the actual reported cases in Israel to validate the model. The root mean square error (RMSE) was 350.09, and the R-squared (R2) was 0.99, indicating a well-fitted model. Scenario 4 demonstrated the most effective prevention and control outcomes. Strengthening non-pharmaceutical interventions and increasing nucleic acid testing frequency, even under low testing capacity, resulted in a delayed epidemic peak by 78 days. The proportion of undetected cases decreased from 77.83% to 31.21%, and the overall testing demand significantly decreased, meeting maximum demand even with low testing capacity. The initiation of testing influenced case detection probability. Under high testing capacity, increasing testing frequency elevated the detection rate from 36.40% to 77.83%. Nucleic acid screening proved effective in reducing the demand for testing resources under diverse epidemic prevention and control strategies. While effective interventions and nucleic acid screening measures substantially diminished the demand for testing-related resources, varying degrees of insufficient testing capacity may still persist. CONCLUSIONS: The nucleic acid detection strategy proves effective in promptly identifying and isolating infected individuals, thereby mitigating the infection peak and extending the time to peak. In situations with constrained testing capacity, implementing more stringent measures can notably decrease the number of infections and alleviate resource demands. The improved SEIR model demonstrates proficiency in predicting both reported and unreported cases, offering valuable insights for future infection risk assessments. Rapid evaluations of testing requirements across diverse scenarios can aptly address resource limitations in specific regions, offering substantial evidence for the formulation of future infectious disease testing strategies.

Optimal resource allocation model for COVID-19: a systematic review and meta-analysis.

BACKGROUND: A lack of health resources is a common problem after the outbreak of infectious diseases, and resource optimization is an important means to solve the lack of prevention and control capacity caused by resource constraints. This study systematically evaluated the similarities and differences in the application of coronavirus disease (COVID-19) resource allocation models and analyzed the effects of different optimal resource allocations on epidemic control. METHODS: A systematic literature search was conducted of CNKI, WanFang, VIP, CBD, PubMed, Web of Science, Scopus and Embase for articles published from January 1, 2019, through November 23, 2023. Two reviewers independently evaluated the quality of the included studies, extracted and cross-checked the data. Moreover, publication bias and sensitivity analysis were evaluated. RESULTS: A total of 22 articles were included for systematic review; in the application of optimal allocation models, 59.09% of the studies used propagation dynamics models to simulate the allocation of various resources, and some scholars also used mathematical optimization functions (36.36%) and machine learning algorithms (31.82%) to solve the problem of resource allocation; the results of the systematic review show that differential equation modeling was more considered when testing resources optimization, the optimization function or machine learning algorithm were mostly used to optimize the bed resources; the meta-analysis results showed that the epidemic trend was obviously effectively controlled through the optimal allocation of resources, and the average control efficiency was 0.38(95%CI 0.25-0.51); Subgroup analysis revealed that the average control efficiency from high to low was health specialists 0.48(95%CI 0.37-0.59), vaccines 0.47(95%CI 0.11-0.82), testing 0.38(95%CI 0.19-0.57), personal protective equipment (PPE) 0.38(95%CI 0.06-0.70), beds 0.34(95%CI 0.14-0.53), medicines and equipment for treatment 0.32(95%CI 0.12-0.51); Funnel plots and Egger's test showed no publication bias, and sensitivity analysis suggested robust results. CONCLUSION: When the data are insufficient and the simulation time is short, the researchers mostly use the constructor for research; When the data are relatively sufficient and the simulation time is long, researchers choose differential equations or machine learning algorithms for research. In addition, our study showed that control efficiency is an important indicator to evaluate the effectiveness of epidemic prevention and control. Through the optimization of medical staff and vaccine allocation, greater prevention and control effects can be achieved.

A network meta-analysis of risk factors of infection among close contacts of COVID-19.

Objective: We aimed to use network meta-analysis to compare the impact of infection risk factors of close contacts with COVID-19, identify the most influential factors and rank their subgroups. It can provide a theoretical basis for the rapid and accurate tracking and management of close contacts. Methods: We searched nine databases from December 1, 2019 to August 2, 2023, which only took Chinese and English studies into consideration. Odd ratios (ORs) were calculated from traditional meta-estimated secondary attack rates (SARs) for different risk factors, and risk ranking of these risk factors was calculated by the surface under the cumulative ranking curve (SUCRA). Results: 25 studies with 152647 participants identified. Among all risk factors, the SUCRA of type of contact was 69.6 % and ranked first. Among six types of contact, compared with transportation contact, medical contact, social contact and other, daily contact increased risk of infection by 12.11 (OR: 12.11, 95 % confidence interval (CI): 6.51-22.55), 7.76 (OR: 7.76, 95 % CI: 4.09-14.73), 4.65 (OR: 4.65, 95 % CI: 2.66-8.51) and 8.23 OR: 8.23, 95 % CI: 4.23-16.01) times, respectively. Overall, SUCRA ranks from highest to lowest as daily contact (94.7 %), contact with pollution subjects (78.4 %), social contact (60.8 %), medical contact (31.8 %), other (27.9 %), transportation contact (6.4 %). Conclusion: The type of contact had the greatest impact on COVID-19 close contacts infection among the risk factors we included. Daily contact carried the greatest risk of infection among six types of contact, followed by contact with pollution subjects, social contact, other, medical contact and transportation contact. The results can provide scientific basis for rapid assess the risk of infection among close contacts based on fewer risk factors and pay attention to high-risk close contacts during management, thereby reducing tracking and management costs.

Hepatic epithelioid hemangioendothelioma metastasized to the peritoneum, omentum and mesentery: a case report.

Epithelioid hemangioendothelioma (EHAE) is a malignant vascular tumor derived from endothelial cell often misdiagnosed as Hepatic carcinoma on the basis of radiological features. Till now etiology of this rare curiosity is unknown but it is related with use of oral contraceptives pills (OCP), liver trauma, exposure to vinyl chloride and hepatitis. We herein report on a case which failed to be diagnosed by cytopathology, computed tomography (CT) and magnetic resonance imaging (MRI). Patient was a 46 yr old man presented with abdominal distension for a month. Initial liver function test (LFT) was increased whereas renal function test (RFT) and alpha-fetoprotein (AFP) were normal. His abdominal ultrasound revealed multiple hypoechoic nodules and multiple liver calcifications. Subsequently laparoscopic omental biopsy and Ultrasound guided liver biopsy was done showing the neoplastic cells scattered in fibrous stroma. The immunohistochemistry for endothelial tumor cells stained positive for Vimentin (+++), CD10 (+++), CD34 (++), CD31 (+), Factor VIII antigen (focal) (+) and low proliferative activity for ki-67. Our case is very interesting in which patient admitted with nonspecific symptoms of abdominal pain and diagnosed to be a Malignant Hepatic EHAE metastasized to the peritoneum, omentum and mesentery. The patient was on thalidomide 50 mg/day and increased to 100 mg/day. 5-Flurouracil (FU) intraperitoneal chemotherapy and other symptomatic and supportive treatment was given to the patient. Our case highlights on the importance of immunohistopathological diagnosis, compare the radiological findings of this disease and discuss the treatment strategy with review of available literature.

Use of nerve elongator to repair short-distance peripheral nerve defects: a prospective randomized study.

Repair techniques for short-distance peripheral nerve defects, including adjacent joint flexion to reduce the distance between the nerve stump defects, "nerve splint" suturing, and nerve sleeve connection, have some disadvantages. Therefore, we designed a repair technique involving intraoperative tension-free application of a nerve elongator and obtained good outcomes in the repair of short-distance peripheral nerve defects in a previous animal study. The present study compared the clinical outcomes between the use of this nerve elongator and performance of the conventional method in the repair of short-distance transection injuries in human elbows. The 3-, 6-, and 12-month postoperative follow-up results demonstrated that early neurological function recovery was better in the nerve elongation group than in the conventional group, but no significant difference in long-term neurological function recovery was detected between the two groups. In the nerve elongation group, the nerves were sutured without tension, and the duration of postoperative immobilization of the elbow was decreased. Elbow function rehabilitation was significantly better in the nerve elongation group than in the control group. Moreover, there were no security risks. The results of this study confirm that the use of this nerve elongator for repair of short-distance peripheral nerve defects is safe and effective.

Metabolomic analysis reveals key metabolites related to the rapid adaptation of Saccharomyce cerevisiae to multiple inhibitors of furfural, acetic acid, and phenol.

During hydrolysis of lignocellulosic biomass, a broad range of inhibitors are generated, which interfere with yeast growth and bioethanol production. In order to improve the strain tolerance to multiple inhibitors--acetic acid, furfural, and phenol (three representative lignocellulose-derived inhibitors) and uncover the underlying tolerant mechanism, an adaptation experiment was performed in which the industrial Saccharomyces cerevisiae was cultivated repeatedly in a medium containing multiple inhibitors. The adaptation occurred quickly, accompanied with distinct increase in growth rate, glucose utilization rate, furfural metabolism rate, and ethanol yield, only after the first transfer. A similar rapid adaptation was also observed for the lab strains of BY4742 and BY4743. The metabolomic analysis was employed to investigate the responses of the industrial S. cereviaise to three inhibitors during the adaptation. The results showed that higher levels of 2-furoic acid, 2, 3-butanediol, intermediates in glycolytic pathway, and amino acids derived from glycolysis, were discovered in the adapted strains, suggesting that enhanced metabolic activity in these pathways may relate to resistance against inhibitors. Additionally, through single-gene knockouts, several genes related to alanine metabolism, GABA shunt, and glycerol metabolism were verified to be crucial for the resistance to multiple inhibitors. This study provides new insights into the tolerance mechanism against multiple inhibitors, and guides for the improvement of tolerant ethanologenic yeast strains for lignocellulose-bioethanol fermentation.

[Reconstruction of soft-tissue defects in hands using the free proximal posterior interrosseous artery forearm perforator flaps].

OBJECTIVE: To investigate the applied anatomy of the proximal posterior interrosseous artery perforator flap (PIAP) and report the clinical results of repairing the soft tissue defects in hands. METHODS: Between September 2007 and January 2011, 21 patients with 24 soft tissue defects in hands were repaired with the free proximal PIAP flap transplantation. The size of the flaps ranged from 2.0 cm x 1.5cm to 7cm x 5cm. The longest length of these flaps was 9 cm. 9 flaps were dissected with one additional superficial vein to anastomose with the superficial vein at the recipient sites. RESULTS: 19 flaps survived completely. Bubbles and violet color happened in 4 flaps which survived finally after partial suture removal. Flap necrosis occurred in one flap. The clinical results were satisfactory after 6-25 months of following-up, and the scars at the donor sites were not obvious. CONCLUSIONS: The free PIAP flaps have constant, reliable blood supply, and good texture. It is a good option for repairing soft-tissue defects in the hands.

[Etiologic investigation of chronic granulomatous inflammation of hand by polymerase chain reaction and DNA sequencing].

OBJECTIVE: To explore the causative pathogens in littoral hand infections which exhibited chronic granulomatous inflammation, the relationship between chronic granulomatous inflammation and mycobacteria and to discuss the prospects of PCR in clinical application for diagnosis of granulomatous inflammation. METHOD: With 16S-rDNA as the target sequence, Nest-PCR was used to detect mycobacteria directly from 37 cases of chronic granulomatous inflammations, and identified them by gene sequencing. RESULTS: Twenty-four of 37 cases were positive for mycobacteria by Nest-PCR, in which 17 were M.marinum, 1 M.chelonae, 2 M.avium, 2 M.kansasii, and 2 M.tubercular through gene sequencing. CONCLUSIONS: Nest-PCR combining gene sequencing proved to be a liable and sensitive method to detect Non-tubercular mycobacteria (NTM) in fresh tissue. NTM is the major factor of hand specific chronic infections other than tubercular. Pathological changes are difficult to differentiate TB from NTM and bacterial evidence was necessary.

[The etiological study, diagnose and therapy of hand special chronic infections in littoral area].

OBJECTIVE: To explore the etiological factors of hand special chronic infections and their relationship with tuberculosis, and to give evidence for clinical diagnosis as well as treatments. METHODS: From 2002 to 2004 pathologic inspection, acid-fast stain, bacterial cultication, mycobacterial cultivation were performed in all 29 cases of hand special chronic infections. RESULTS: All cases showed granulomatous lesions in pathological appearance, 2 positive in acid-fast stain, 12 positive in bacteria cultivation, and 1 nocardiosis, 1 staphylococcus epidermidis, 7 M.marinum, 1 M.tuberculosis, 1 M.fortuitum, 1 M.kansasii. CONCLUSIONS: Non-tuberculo-mycobacterium (NTM) especially M.marinum are far more important as the major factor than tuberculosis and other bacterial in hand special chronic infections. Bacteria cultivation should be routine examined for all cases.

Effects of simvastatin on activities of endogenous antioxidant enzymes and angiotensin-converting enzyme in rat myocardium with pressure-overload cardiac hypertrophy.

AIM: To investigate effects of simvastatin (Sim) on the activities of antioxidant enzymes and angiotensin-converting enzyme in rat myocardium with pressure-overload cardiac hypertrophy. METHODS: Left ventricular hypertrophy (LVH) was induced by partly constricting rat abdominal aorta between the left and right renal artery. Rats were given ig Sim 1.8 and 3.6 mg . kg-1 . d-1 for 8 weeks following 6 weeks aortic constriction. Activities of antioxidant enzymes and angiotensin-converting enzyme, and lipid peroxidation of left ventricular (LV) tissue were determined. RESULTS: Contents of angiotensin II and thiobarbituric acid reactive substances (TBARS), and activity of ACE in LVH group (n = 8) were increased by 163 %, 90 %, and 130 %, respectively (P < 0.01)compared with sham-operated group (n = 7), and were decreased by 30 %, 37 %, and 51 %, respectively (P < 0.01) in high dosage Sim treatment group (n = 9) compared with LVH group. Activities of catalase and glutathione peroxidase of LV tissue in LVH group were decreased by 29 % and 23 % (P < 0.01) compared with sham-operated group, and were increased by 32 % and 22 % (P < 0.01) in high dosage Sim treatment group compared with LVH group. Activity of Cu, Zn-superoxide dismutase (SOD) of LV tissue was increased by 33 % in LVH group compared with sham-operated group. Sim treatment did not significantly affect activity of Cu,Zn-SOD. CONCLUSION: Alteration of redox status in myocardium is associated with cardiac hypertrophy and inhibitory effects of Sim on cardiac hypertrophy in rats model might be linked to its antioxidant effects.