Hydrogels are crosslinked polymer chains with three-dimensional (3D) network structures, which can absorb relatively large amounts of fluid. Because of the high water content, soft structure, and porosity of hydrogels, they closely resemble living tissues. Research in recent years shows that hydrogels have been applied in various fields, such as agriculture, biomaterials, the food industry, drug delivery, tissue engineering, and regenerative medicine. Along with the underlying technology improvements of hydrogel development, hydrogels can be expected to be applied in more fields. Although not all hydrogels have good biodegradability and biocompatibility, such as synthetic hydrogels (polyvinyl alcohol, polyacrylamide, polyethylene glycol hydrogels, etc.), their biodegradability and biocompatibility can be adjusted by modification of their functional group or incorporation of natural polymers. Hence, scientists are still interested in the biomedical applications of hydrogels due to their creative adjustability for different uses. In this review, we first introduce the basic information of hydrogels, such as structure, classification, and synthesis. Then, we further describe the recent applications of hydrogels in 3D cell cultures, drug delivery, wound dressing, and tissue engineering.

Coronavirus Disease 2019 (COVID-19) pandemic, which is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become the global challenge. Reaching global herd immunity will help end the COVID-19 pandemic. However, vaccine shortage and vaccine hesitancy are the obstacles to achieve global herd immunity against SARS-CoV-2. The current homologous vaccine regimen is experimentally switching to heterologous vaccination at several study sites. However, the reactogenicity of heterologous ChAdOx1-S and mRNA vaccination against SARS-CoV-2 is still unclear. We have conducted a systematic review to summarize the current findings on the safety and immunogenicity of this heterologous vaccination and elucidate their implications against SARS-CoV-2. This systematic review was conducted by the guidelines of PRISMA. Articles were searched from PubMed and other sources (MedRixv and Google scholar) starting from 1 January to 5 September 2021. The search term was heterologous ChAdOx1-S and BNT162b2 or mRNA-1273 vaccination. Our review found that participants with ChAdOx1/BNT162b2, ChAdOx1-S/mRNA-1273 or BNT162b2/ChAdOx1-S did not have the serious adverse events seen with homologous vaccination. Participants with the heterologous regimen (ChAdOx1/BNT162b2, ChAdOx1-S/mRNA-1273 or BNT162b2/ChAdOx1-S), compared with those with two doses of ChAdOx1-S, have shown a more robust immune responses against SARS-CoV-2, such as higher levels of responsive antibodies or increased numbers of spike-specific T-cells. Nevertheless, these immune responses were slightly diminished in the recipients of BNT162b2/ChAdOx1-S. Also, the safety study of heterologous ChAdOx1-S/mRNA vaccination was based on small populations. Further studies to enclose diverse categories, such as race/ethnicity or geography, may be necessary. Overall, the heterologous immunization with ChAdOX1-S and the mRNA vaccine may improve the vaccine shortage related slow pace of reaching herd immunity, especially using the heterologous immunization with ChAdOx1-S/BNT162b2.

Objective-This study was to investigate the effects of chronic exercise on vasodilatation and endothelial intracellular calcium (EC [Ca 2ϩ ] i ) signaling in atherosclerotic animals. Methods and Results-For 8 weeks, male New Zealand White rabbits were fed rabbit chow with or without the addition of 2% cholesterol. They were further divided into control and exercise groups. Animals in the exercise groups ran on a leveled treadmill at 0.88 km/h for 10 to 60 minutes gradually for 5 days per week for a total of 8 weeks. At the end of experiments, femoral arteries were dissected, loaded with fura 2-AM, and mounted in a tissue flow chamber. PE-precontracted vessel specimens were exposed to acetylcholine (ACh). The EC [Ca 2ϩ ] i elevation and vasorelaxation were determined simultaneously under an epifluorescence microscope equipped with a ratio-imaging capability. Our results showed the following: (1) high cholesterol diet feeding caused lipid deposition on vascular surface, reduced the ACh-evoked EC [Ca 2ϩ ] i elevation, and impaired endothelium-dependent and endothelium-independent vascular responses, but chronic exercise had the opposite effects; (2) ACh-induced vasorelaxation was associated with EC [Ca 2ϩ ] i elevation in all groups; and (3) vasorelaxation at high levels of EC [Ca 2ϩ ] i elevation decreased in hypercholesterolemia. Conclusions-Our data suggest that hypercholesterolemia induces vascular structural changes and impairs EC [Ca 2ϩ ] i signaling and vasodilatation, whereas chronic exercise partially reverses these adverse effects. Key Words: chronic exercise Ⅲ high cholesterol diet Ⅲ nitric oxide Ⅲ calcium signaling Ⅲ vasodilators A therosclerosis is the leading cause of mortality in the developed world, and it is possibly caused by a high-fat diet and a sedentary lifestyle. 1 Risk factors of atherosclerosis, ie, elevated LDL cholesterol levels, diabetes mellitus, hypertension, homocystinemia, and smoking, are associated with vascular dysfunction, such as monocyte adhesion and invasion, smooth muscle proliferation and migration, platelet activation, and extracellular matrix formation. 2 Moreover, the atherogenesis-related endothelial impairment occurs well before any detectable structural changes of the vessel wall. 3 Normally, the vascular endothelial cells release NO. 4 NO relaxes vascular smooth muscle, inhibits platelet adhesion/ aggregation, inhibits monocyte adhesion and migration, reduces the production of superoxide, inhibits oxidation of LDL, and inhibits smooth muscle proliferation and migration. Therefore, it is considered to be an endogenous antiatherosclerotic factor. 5 It is likely that the impairment of endothelium-derived NO activity is a cause, not a consequence, of atherosclerosis.Current consensus indicates that regular exercise reduces the incidence of cardiovascular diseases and death or causes a regression of symptoms. 1,6 -8 Several possible mechanisms of these exercise effects have been proposed, such as an increase in HDL cholesterol level, 9,10 a decrease in the oxi...

The role of endothelial calcium signaling in exercise-enhanced ACh-induced vasorelaxation was examined using male Wistar rats (8∼10 wk old) that were divided into control and exercise groups. The exercised animals ran on a treadmill with progressive increments of speed until exhaustion. After decapitation, aortic rings were dissected and loaded with fura 2-AM. After being mounted on a tissue flow chamber, vessels were precontracted with phenylephrine, and ACh-induced endothelial calcium elevation and vasorelaxation were determined simultaneously under an epifluorescence microscope equipped with ratio imaging capability. Our results showed that 1) there was logarithmic correlation between endothelial calcium elevation and vasorelaxation; 2) acute exercise enhanced ACh-induced endothelial calcium elevation and vasorelaxation without altering their relationship; 3) pretreatment with N ω-nitro-l-arginine markedly reduced ACh-induced vasorelaxation in both groups but suppressed the calcium response only in the exercise group; and 4) the exercise effect on endothelial calcium elevation was abolished by Ca2+-free buffer or gadolinium. In conclusion, acute exercise increases ACh-induced vasorelaxation by increasing the endothelial calcium influx and the calcium-dependent nitric oxide release.

Since countries commenced COVID-19 vaccination around the world, many vaccine-related adverse effects have been reported. Among them, short-term memory loss with autoimmune encephalitis (AE) was reported as a rare adverse effect. Since case numbers are limited, this brief report may draw the attention of the medical community to this uncommon adverse effect and serve as a reference for future vaccine improvement. However, given the high risk of adverse outcomes when infected with SARS-CoV-2 and the clearly favorable safety/tolerability profile of existing vaccines, vaccination is still recommended.

Rationale:Posterior reversible encephalopathy syndrome (PRES), which diagnosis is based on clinical symptoms and radiological features, is a neurotoxic disease characterized by a set of clinical manifestations, such as seizure, headache, visual, and/or consciousness disturbance. It is the first case of PRES followed by postpartum hemorrhage (PPH) without underlying disease.Patient concerns:A 37-year-old healthy woman had PPH after caesarean section. Six days after delivery, headache occurred suddenly, followed by episodes of clonus seizure.Diagnoses:Brain computed tomography showed ischemic stroke. However, magnetic resonance imaging revealed characteristics consistent with PRES.Interventions:The patient received phenytoin for seizure control.Outcomes:Seizure was under good control over the following days. Three months later, repeated magnetic resonance imaging showed complete remission.Lessons:PRES may be triggered by PPH and is not necessarily secondary to typical predisposing factors such as hypertension or pre/eclampsia. Hormone fluctuation, increased blood pressure variation, and massive blood transfusion may be contributed to the development of PRES in our case. Also, it is necessary to rule out those life-threatening diseases, such as cavernoma hemorrhage, cerebral venous thrombosis, and ischemic stroke before the diagnosis of PRES.

Background/Aim: Whole-body positron-emission tomography/computed tomography with the glucose analog 2-[ 18 F]fluoro-2-deoxy-D-glucose (FDG-PET/CT) has been used to screen examinees for underlying malignancy in many countries. The aim of this study was to compare the potential value of FDG-PET/CT application in asymptomatic individuals with those with suspected malignancy. Patients and Methods: A total of 9,408 examinees underwent wholebody FDG-PET/CT at our hospital from July 2006 to August 2013. Three thousand and seven hundred asymptomatic individuals and 848 individuals with laboratory and clinical/radiologicaI suspicion of malignancy who had undergone FDG-PET/CT for cancer screening were recruited. The final confirmation of cancer and outcomes were based on a pathological report and continuous followup. Results: Forty-five out of 3,700 asymptomatic individuals (1.2%) had proven malignancy, and 42 of them (93.3%) were found by FDG-PET/CT. Two hundred and twelve out of 848 with suspected malignancy (25%) had proven malignancy, and 196 of them (92.5%) were detected by FDG-PET/CT. Most of these cancers in asymptomatic individuals were clinically at an early stage. The discovery rate in asymptomatic individuals and those with suspected malignancy was 1.1% and 23.1%, respectively. The overall survival of patients with cancer diagnosed with PET/CT was higher than those with suspected malignancy (78.6% vs.

The aim of this study was to investigate the influence of previous mammography screening on the performance of breast cancer detection. The screened women were divided into first-visit and follow-up groups for breast cancer screening. The positive predictive value (PPV), cancer detection rate (CDR), and recall rate were used to evaluate and analyze the overall screening performance among the two groups. Among them, 10,040 screenings (67.2%) were first visits and 4895 screenings (32.8%) were follow-up visits. The proportion of positive screening results for first-visit participants was higher than that for their follow-up counterparts (9.3% vs. 4.0%). A total of 98 participants (74 first-visit and 24 follow-up visit) were confirmed to have breast cancer. The PPV for positive mammography for women who underwent biopsy confirmation was 28.7% overall, reaching 35.8% for the follow-up visit group and 27.0% for the first-visit group. The CDR was 6.6 per 1000 overall, reaching 7.4 per 1000 for first-visit group and 4.9 per 1000 for the follow-up group. The overall recall rate was 7.9%, reaching 9.7% for the first-visit group and 4.2% for the follow-up group. The PPV is improved and the recall rate is decreased if prior mammography images are available for comparison when conducting mammography screening for breast cancer. By this study, we concluded that prior mammography plays an important role for breast cancer screening, while follow-up mammography may increase the diagnostic rate when compared to the prior mammography. We suggest that the public health authority can encourage subjects to undergo screenings in the same health institute where they regularly visit.