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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.

The global COVID-19 vaccination campaign has raised concerns about potential side effects, including cardiac involvement or axillary lymphadenopathy. This study investigated the relationship between COVID-19 vaccination and thallium-201 myocardial perfusion imaging (Tl-201 MPI) findings, aiming to elucidate the impact of the vaccine impact on cardiac health. This retrospective analysis enrolled patients referred for MPI examination post-COVID-19 vaccination between June 2021 and January 2022. Eligible participants included symptomatic individuals without prior coronary artery disease (CAD) or with stable CAD, experiencing symptoms within one-month post-vaccination. MPI was conducted post dipyridamole-stress testing, and positive stress test results were further evaluated by cardiac catheterization. The association between vaccination and MPI results, including axillary lymphadenopathy presence, was assessed. Sixty-four patients were included, with a mean age of 54.7 years, and a predominance of males (64.3%). A notable incidence of positive MPI findings and axillary lymphadenopathy was observed, particularly in patients vaccinated with mRNA vaccines. Among the 15 patients with positive MPI, visible axillary lymphadenopathy was observed in 4 cases (26.7%), compared with 6 of 49 patients (12.2%) with negative MPI. Although this difference was not statistically significant, it suggests a possible trend toward a higher prevalence in the MPI-positive subgroup. Most patients with positive MPI findings had received the Moderna vaccine. Our findings indicate a potential link between mRNA COVID-19 vaccination and cardiac issues detected via MPI, as well as an increase in axillary lymphadenopathy. Although further prospective studies are warranted to establish causality, our findings underscore the importance of post-vaccination monitoring, particularly in symptomatic patients, and the need of continued efforts to comprehensively assess vaccine safety to help reduce mortality rates.

This study aimed to explore changes in cardiovascular performance among patients with thyroid cancer following thyroidectomy, radioiodine therapy (RAIT) and thyroid-stimulating hormone suppression therapy (TST), with or without treatment with tyrosine kinase inhibitors (TKIs). We enrolled 32 patients who underwent thyroidectomy and subsequent RAIT (except for one patient who underwent partial thyroidectomy only) and TST, with or without TKI therapy. We assessed myocardial perfusion using quantitative myocardial perfusion imaging (qMPI), myocardial blood flow (MBF), and coronary flow reserve (CFR) dynamic single photon-emission computed tomography/computer tomography. We also analyzed data from laboratory tests or heart-related circulation markers, such as -terminal pro B-type natriuretic peptide (NT-proBNP) to compare patient results, including correlations with different TKIs, RAIT, and TST. qMPI indicated that the TKI-treated group (n=19) exhibited reduced MBF, CFR, and coronary flow capacity compared to the non-TKI-treated group. The right coronary artery (RCA) territory was notably affected by TKI treatment, particularly during the stress phase: RCA-stress blood flow: 2.4±0.6 1.9±0.7 ml/min/g; RCA-CFR: 2.3±0.8 2.93±0.9 for TKI-treated non TKI-treated groups, respectively. This effect was more pronounced in the subgroup undergoing sequential anti-vascular endothelial growth factor TKI treatment ( sorafenib and lenvatinib) (n=4) compared to non-TKI-treated controls. Additionally, TKI-treated patients showed a higher mean NT-ProBNP level (203±322.2 pg/ml) than non-TKI-treated patients (39.1±36 pg/ml). Abnormal MBF/CFR was also associated with higher cumulative RAIT dose and lower thyrotropin level. TKI therapy, especially anti-vascular endothelial growth factor TKI, can negatively affect myocardial perfusion and lead to coronary microcirculation dysfunction, reducing MBF/CFR during the stress phase. The link between cumulative RAIT dose, lower thyroid-stimulating hormone level, and abnormal MBF/CFR highlights the need for further research.

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.

A 50-year-old woman presented a rapidly proliferative cystic lesion in the left pelvis as displayed by sonography. Exploratory laparoscopy with omental biopsy suggested pseudomyxoma peritonei (PMP). An 18F-FDG PET/CT revealed scalloping of the liver surface with an associated extrahepatic lesion exhibiting moderate FDG avidity and strand-like FDG uptake within a left-sided septated ovarian cyst. The diagnosis of low-grade appendiceal mucinous neoplasms was proven after cytoreductive surgery. This case provided important imaging features on 18F-FDG PET/CT that directed the pre-operative diagnosis and the initiation of treatment.

Background/Objectives: Tl-201 myocardial perfusion single-photon emission computed tomography (MPS) is a minimally invasive test for patients with suspected coronary artery disease (CAD). While its predictive and prognostic values are well established, diagnostic performance varies. A recent meta-analysis reported that the sensitivity and specificity of MPS range from 48.8 to 100% and 46.7 to 94.7%, respectively, reflecting discordance between CAG. Little is known, however, about the influence of patients’ characteristics and CAD risk factors on the diagnostic performance of MPS. This study aims to evaluate these factors in relation to MPS performance. Methods: We screened 4817 consecutive patients referred to our Nuclear Medicine Department in 2015 for Tl-201 MPS. Patients with clinically suspected ischemic heart disease who underwent CAG within 60 days post-MPS were included in the present analysis. The percentage of agreement/disagreement between the MPS-abnormal/normal and CAG-positive/negative groups was evaluated. Additionally, patient characteristics, CAD risk factors, co-morbidities, and single-photon emission computed tomography (SPECT) image-derived parameters were compared among the patients. Results: Among 635 patients with abnormal MPS, 583 had coronary stenosis. For the 52 without stenosis, causes included non-obstructive CAD (34.6%), prior infarction with scarring (32.7%), and imaging artifacts (32.7%). Significant stenosis was associated with older age, male sex, diabetes, dyslipidemia, CKD, and prior PCI, while hypertension and higher BMI were more common in insignificant CAD. Among 104 patients with normal MPS, 79 had stenosis, mainly in the LAD. Clinical risk factors were more prevalent in patients with any degree of stenosis. Conclusions: In patients with an abnormal MPS, the incorporation of visual interpretation, parameters, and CAD risk factors increases specificity and helps differentiate obstructive from non-obstructive CAD.

We report a case of a 73-year-old man with minimally invasive lung adenocarcinoma, post-resection, evaluated with 18F-FDG PET/CT for suspected disease progression. Imaging showed increased FDG uptake in the right lower lung mass and systemic lymphadenopathy (mediastinal, supraclavicular, axillary, paraaortic, and iliac regions). The appearance of a stable lymph node and a clinical history of IgG4 lymphadenopathy suggested an inflammatory process, although malignancy in the lung mass and mediastinal nodes could not be excluded. Lobectomy confirmed the presence of lung adenocarcinoma, while radical lymph node dissection identified IgG4-related lymphadenopathy without metastasis. This case underscores the need for considering differential diagnosis of PET-positive lymphadenopathy, especially in patients with comorbid conditions that mimic or coexist with malignancy.

A 31-year-old man was diagnosed with a COVID-19 infection, presenting with a diffuse headache and an uneven sensation of fullness, despite having no prior systemic diseases. 99mTc-ECD Brain SPECT/CT revealed a marked decrease in blood perfusion in the cerebral cortices, predominantly in the frontal region and involving the olfactory sulcus. In contrast, there was increased perfusion in the occipital lobe and asymmetrical perfusion in the cerebellum. This case highlights changes in regional blood flow perfusion that might affect the functional connectivity of the pain matrix, leading to the onset of headaches and associated underlying mechanisms.

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.

Background/Aim: Whole-body positron-emission tomography/computed tomography with the glucose analog 2-[18F]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 whole-body 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 follow-up. 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. 48.5%, p<0.001). Patients with a resectable lesion, early-stage disease, and lower maximal standardized uptake value had significantly better survival than those without. Conclusion: FDG-PET/CT is useful in the early diagnosis of cancer and thus might improve the survival rates of these patients. Considering the costs and risk of radiation exposure, it would be better used as a priority in patients with laboratory and clinical/radiologic suspicion of malignancy.