Mycobacterial Preauricular Sinus Abscess: A Case Series.

Preauricular sinus is a common congenital external ear anomaly. It occurs due to the incomplete fusion of hillocks of His of the first and second branchial arches. Tuberculosis (TB) is endemic in Malaysia, which imposes a major public health problem. It is caused by Mycobacterium tuberculosis, which causes chronic, recurrent diseases and poor healing of a wound. Pulmonary TB is the most common form of infection, some manifesting as extrapulmonary TB. We share our experience in managing a series of three patients with recurrent tuberculous preauricular sinus abscesses in different age groups. Testing for acid-fast bacilli is highly advocated in recurrent cases and in extensive infection of preauricular sinuses despite the absence of systemic or pulmonary symptoms. Treatment with anti-tuberculous drugs is commenced, followed by an elective sinus excision once the patient is free from infection to prevent recurrence.

Immunological memory to Common Cold Coronaviruses assessed longitudinally over a three-year period

Understanding immune memory to Common Cold Coronaviruses (CCCs) is relevant for assessing its potential impact on the outcomes of SARS-CoV-2 infection, and for the prospects of pan-corona vaccines development. We performed a longitudinal analysis, of pre-pandemic samples collected from 2016-2019. CD4+ T cells and antibody responses specific for CCC and to other respiratory viruses, and chronic or ubiquitous pathogens were assessed. CCC-specific memory CD4+ T cells were detected in most subjects, and their frequencies were comparable to those for other common antigens. Notably, responses to CCC and other antigens such as influenza and Tetanus Toxoid (TT) were sustained over time. CCC-specific CD4+ T cell responses were also associated with low numbers of HLA-DR+CD38+ cells and their magnitude did not correlate with yearly changes in the prevalence of CCC infections. Similarly, spike RBD-specific IgG responses for CCC were stable throughout the sampling period. Finally, high CD4+ T cell reactivity to CCC, but not antibody responses, was associated with high pre-existing SARS-CoV-2 immunity. Overall, these results suggest that the steady and sustained CCC responses observed in the study cohort are likely due to a relatively stable pool of CCC-specific memory CD4+ T cells instead of fast decaying responses and frequent reinfections.

Design of immunogens for eliciting antibody responses that may protect against SARS-CoV-2 variants

The rise of SARS-CoV-2 variants and the history of outbreaks caused by zoonotic coronaviruses point to the need for next-generation vaccines that confer protection against variant strains. Here, we combined analyses of diverse sequences and structures of coronavirus spikes with data from deep mutational scanning to design SARS-CoV-2 variant antigens containing the most significant mutations that may emerge. We trained a neural network to predict RBD expression and ACE2 binding from sequence, which allowed us to determine that these antigens are stable and bind to ACE2. Thus, they represent viable variants. We then used a computational model of affinity maturation (AM) to study the antibody response to immunization with different combinations of the designed antigens. The results suggest that immunization with a cocktail of the antigens is likely to promote evolution of higher titers of antibodies that target SARS-CoV-2 variants than immunization or infection with the wildtype virus alone. Finally, our analysis of 12 coronaviruses from different genera identified the S2 cleavage site and fusion peptide as potential pan-coronavirus vaccine targets. Author SummarySARS-CoV-2 variants have already emerged and future variants may pose greater threats to the efficacy of current vaccines. Rather than using a reactive approach to vaccine development that would lag behind the evolution of the virus, such as updating the sequence in the vaccine with a current variant, we sought to use a proactive approach that predicts some of the mutations that could arise that could evade current immune responses. Then, by including these mutations in a new vaccine antigen, we might be able to protect against those potential variants before they appear. Toward this end, we used various computational methods including sequence analysis and machine learning to design such antigens. We then used simulations of antibody development, and the results suggest that immunization with our designed antigens is likely to result in an antibody response that is better able to target SARS-CoV-2 variants than current vaccines. We also leveraged our sequence analysis to suggest that a particular site on the spike protein could serve as a useful target for a pan-coronavirus vaccine.

Distinguishing COVID-19 infection and vaccination history by T cell reactivity

SARS-CoV-2 infection and COVID-19 vaccines elicit memory T cell responses. Here, we report the development of two new pools of Experimentally-defined T cell epitopes derived from the non-spike Remainder of the SARS-CoV-2 proteome (CD4RE and CD8RE). The combination of T cell responses to these new pools and Spike (S) were used to discriminate four groups of subjects with different SARS-CoV-2 infection and COVID-19 vaccine status: non-infected, non-vaccinated (I-V-); infected and non-vaccinated (I+V-); infected and then vaccinated (I+V+); and non-infected and vaccinated (I-V+). The overall classification accuracy based on 30 subjects/group was 89.2% in the original cohort and 88.5% in a validation cohort of 96 subjects. The T cell classification scheme was applicable to different mRNA vaccines, and different lengths of time post-infection/post-vaccination. T cell responses from breakthrough infections (infected vaccinees, V+I+) were also effectively segregated from the responses of vaccinated subjects using the same classification tool system. When all five groups where combined, for a total of 239 different subjects, the classification scheme performance was 86.6%. We anticipate that a T cell-based immunodiagnostic scheme able to classify subjects based on their vaccination and natural infection history will be an important tool for longitudinal monitoring of vaccination and aid in establishing SARS-CoV-2 correlates of protection.

Differential T cell reactivity to seasonal coronaviruses and SARS-CoV-2 in community and health care workers

Herein we measured CD4+ T cell responses against common cold corona (CCC) viruses and SARS-CoV-2 in high-risk health care workers (HCW) and community controls. We observed higher levels of CCC reactive T cells in SARS-CoV-2 seronegative HCW compared to community donors, consistent with potential higher occupational exposure of HCW to CCC. We further show that SARS-CoV-2 reactivity of seronegative HCW was higher than community controls and correlation between CCC and SARS-CoV-2 responses is consistent with cross-reactivity and not associated with recent in vivo activation. Surprisingly, CCC reactivity was decreased in SARS-CoV-2 infected HCW, suggesting that exposure to SARS-CoV-2 might interfere with CCC responses, either directly or indirectly. This result was unexpected, but consistently detected in independent cohorts derived from Miami and San Diego.

Newborn dried blood spots for serological surveys of COVID-19

As COVID-19 continues to spread across the globe, the need for inexpensive, large-scale prevalence surveillance testing increases. We present a method for testing newborn dried blood spots (DBS) for anti-SARS-COV-2 IgG antibodies, and demonstrate its applicability as an easily accessible proxy for measuring maternal seroprevalence.

Sex differences in immune responses to SARS-CoV-2 that underlie disease outcomes

A growing body of evidence indicates sex differences in the clinical outcomes of coronavirus disease 2019 (COVID-19)1-4. However, whether immune responses against SARS-CoV-2 differ between sexes, and whether such differences explain male susceptibility to COVID-19, is currently unknown. In this study, we examined sex differences in viral loads, SARS-CoV-2-specific antibody titers, plasma cytokines, as well as blood cell phenotyping in COVID-19 patients. By focusing our analysis on patients with mild to moderate disease who had not received immunomodulatory medications, our results revealed that male patients had higher plasma levels of innate immune cytokines and chemokines including IL-8, IL-18, and CCL5, along with more robust induction of non-classical monocytes. In contrast, female patients mounted significantly more robust T cell activation than male patients during SARS-CoV-2 infection, which was sustained in old age. Importantly, we found that a poor T cell response negatively correlated with patients age and was predictive of worse disease outcome in male patients, but not in female patients. Conversely, higher innate immune cytokines in female patients associated with worse disease progression, but not in male patients. These findings reveal a possible explanation underlying observed sex biases in COVID-19, and provide important basis for the development of sex-based approach to the treatment and care of men and women with COVID-19.

Protective effects of tirofiban on ischemia/reperfusion-induced renal injury in vivo and in vitro.

Tirofiban, a glycoprotein IIb/IIIa receptor inhibitor, is widely used in the management of patients with unstable angina or myocardial infarction, and shows protective effects on ischemia/reperfusion (I/R) injured heart. Whether or not it has protective effect on I/R injured kidney is not known. The present in vivo and in vitro study found that serum creatinine (SCR) and blood urea nitrogen (BUN) were significantly increased in I/R rats, accompanied by histopathological damage of the kidney. Apoptotic cells, leukocyte infiltration and ROS production were increased in I/R rats. Pretreatment by intravenous injection of tirofiban (200µg/kg) reduced SCR and BUN levels, ameliorated renal histopathological changes, and decreased ROS production, cell apoptosis and leukocyte infiltration in I/R injured kidney. Our further study showed that the protection of tirofiban might be associated with the restoration of eNOS/iNOS balance, since inhibition of NO production blocked the tirofiban-mediated renal protection on I/R injury. The present in vivo and in vitro study indicated that tirofiban pretreatment exerts a protective effect on I/R injury in kidney through regulation of eNOS/iNOS balance.

Embedded system design of color-blind image processing / 中国医疗器械杂志

An ARM-based embedded system design schemes is proposed for the color-blind image processing system. The hardware and software of the embedded color-blind image processing system are designed using ARM core processor. Besides, a simple and convenient interface is implemented. This system supplies a general hardware platform for the applications of color-blind image processing algorithms, so that it may bring convenience for the test and rectification of color blindness.

Finite Element Analysis (FEA) for the structure capacity of proximal femur during falling--(II). The effects of falling configuration and load locations on the structural capacity of the proximal femur / 生物医学工程学杂志

The effects of loading conditions on the structural capacity of the proximal femur were investigated parametrically by Finite Element Analysis (FEA) combined with Hoffman failure criterion. The loading conditions included the fall configuration angles, load locations and the friction resistance in hip joint. The results of this parametric study revealed that the load locations are the keys to determining the structural capacity of the proximal femur. There are two low peaks of the structural capacity when the loads are applied to femoral head. If the impact load were applied in this area, the fracture risk would be great. The frictional resistance of the hip joint can severely affect the failure load, which has far reaching implications in terms of osteoarthritis.

Finite element analysis (FEA) for the structure capacity of proximal femur during falling--(I) FEA model and the failure criteria for the bone / 生物医学工程学杂志

Femur fracture from falls is considered one of the most serious types of the elderly. FEA has proved to be an extremely useful tool in the structure analysis of the proximal femur. In this paper, a FEA model of proximal femur is introduced, and Hoffman failure criteria are built based on the experimental strength data for both cortical bone and trabecular bone of the femur from some references. The FEA model and the failure criteria are verified using other researcher's experimental results. The predicted trabecular failure load was only 0.5% lower than the experimental data and cortical failure load was 4.2% higher than the experimental result. This result shows that our FEA model, combined with the Hoffman criterion for both cortical bone and trabecular bone, can effectively predict the structural capacity of the femur during falling.