Evaluation of Hypocalcemia Following Total Laryngectomy With and Without Thyroidectomy.

OBJECTIVE: Hypoparathyroidism and associated hypocalcemia are well-established complications following laryngectomy. This study further characterizes the rates of hypocalcemia in patients undergoing total laryngectomy (TL) with and without thyroidectomy and hemithyroidectomy. STUDY DESIGN: Retrospective cohort study. SETTING: TriNetX. METHODS: We queried TriNetX, a deidentified patient database, to identify patients who underwent TL with and without thyroidectomy and hemithyroidectomy. Rates of hypocalcemia, low parathyroid hormone (PTH), calcium, and calcitriol supplementation were compared between groups with multivariable repeated measures logistic regression. RESULTS: We identified 870 patients in the TL without thyroidectomy cohort, 158 patients in the hemithyroidectomy cohort, and 123 in the total thyroidectomy cohort. Rates of hypocalcemia differed between patients receiving total thyroidectomy versus TL alone for 0 to 1 month (odds ratio [OR]: 2.88 [1.95-4.26]) 1 to 6 months (OR: 5.08 [2.29-11.3]), and 6 to 12 months (OR: 2.63 [1.003-6.88]) postoperatively, with adjustment for age at laryngectomy, race, ethnicity, and gender. Results were similar among those who received calcium supplementation. The rate of low PTH levels differed in these groups for 0 to 1 month (OR: 5.13 [3.10-8.51]), 1 to 6 months (OR: 3.47 [1.46-8.22]), and 6 to 12 months (OR: 3.63 [1.40-9.38]) following surgery. Rates of postoperative calcium supplementation were increased for patients receiving total thyroidectomy versus TL for 1 to 6 months (OR: 2.44 [1.62-3.68]), and 6 to 12 months following surgery (OR: 1.79 [1.18-2.72]). CONCLUSION: Patients undergoing TL with total thyroidectomy have a higher risk of postoperative hypocalcemia compared to patients receiving TL alone. Risk of parathyroid injury in these patients may warrant further emphasis on PTH measurement after surgery and a multidisciplinary approach to management.

Early Celecoxib Use in Spontaneous Intracerebral Hemorrhage is Associated with Reduced Mortality.

BACKGROUND: Hemorrhagic strokes constitute 10-15% of all strokes and have the worst mortality and morbidity of all subtypes. Mortality and morbidity of spontaneous intracerebral hemorrhage (sICH) are often secondary to the effects of inflammation, brain edema, and swelling. Studies have shown that celecoxib, a selective cyclooxygenase 2 (COX-2) inhibitor, reduces perihematomal edema formation and inflammation. This study aimed to examine the impact of celecoxib on sICH outcomes. METHODS: TriNetX, a multi-institutional research database, was retrospectively queried to identify patients with sICH. Outcomes in patients who received celecoxib within 5 days (cohort 1) were analyzed and compared to those in patients who did not receive celecoxib (cohort 2). The primary end point was mortality within 1 year of sICH. Secondary end points included ventilator dependence, tracheostomy, percutaneous endoscopic gastrostomy tube placement, craniotomy, deep venous thrombosis, pulmonary embolism, ischemic stroke, transient ischemia attack, myocardial infarction, and seizures. Further analysis was performed to assess these outcomes for patients treated with ibuprofen, a nonselective COX inhibitor. RESULTS: After propensity score matching, 833 patients were identified in each cohort based on celecoxib use. Mortality at 1 year was significantly reduced in patients with sICH receiving celecoxib compared to those who did not (13.33% vs. 17.77%; p = 0.0124). Risks of ventilator dependence, tracheostomy, percutaneous endoscopic gastrostomy tube placement, craniotomy, deep venous thrombosis, pulmonary embolism, ischemic stroke, transient ischemia attack, myocardial infarction, and seizures were not significantly increased in patients who received celecoxib within 5 days of sICH compared to those who did not receive celecoxib. There was no significant difference in mortality between patients based on ibuprofen administration. CONCLUSIONS: There exists a growing interest in using COX-2 as a potential target strategy for neuroprotection in patients with sICH, with some evidence of a mortality benefit in small cohort studies. This study shows that early celecoxib use is associated with decreased mortality in patients with sICH.

Factors Associated With Inadequate Health Literacy: An Academic Otolaryngology Clinic Population Study.

Objective: To characterize the prevalence of inadequate health literacy among otolaryngology patients and assess the association of individual patient factors with inadequate health literacy. Study Design: Cross-sectional study. Setting: Tertiary academic medical center otolaryngology clinic. Methods: Adult patients presenting to the clinic were recruited from March to June 2022. Participants completed a validated health literacy questionnaire in the waiting room. Data on age, sex, race, insurance, county of residence, and language were extracted from the electronic medical record, linked to the survey responses, and deidentified for analysis. Logistic regression analyses assessed the association between inadequate health literacy and patient factors. Results: Of 374 participants, the mean age was 54.8 years (SD = 17.8) and most were white (79%) and native English speakers (95%). The median health literacy score was 14.5 (Q1-Q3: 12.0-15.0) and 43 participants (12%) had inadequate health literacy. Bivariate analysis showed the odds of inadequate health literacy were 2.5 times greater for those with public insurance (95% confidence interval [CI]: 1.24-5.20, P = .011), 3.5 times greater for males (95% CI: 1.75-6.92, P < .001), and significantly different among race groups (P = .003). When all factors were evaluated simultaneously with multivariable regression, only sex (P < .001) and race (P = .005) remained significant predictors of inadequate health literacy. There were no significant associations between health literacy and age or rurality. Conclusion: Inadequate health literacy was associated with sex and race, but not with age or rurality. 12% of patients had inadequate health literacy, which may perpetuate disparities in care and necessitate interventions to improve care delivery in otolaryngology.

Incidence of tethered cord syndrome in neurofibromatosis types 1 and 2 pediatric patients: a population-level analysis.

PURPOSE: Tethered spinal cord syndrome (TCS) is characterized by cutaneous attachments on the filum terminale that stretch the spinal cord, leading to musculoskeletal and urogenital sequelae. While the neurocutaneous associations with TCS remain undefined, a recent study reports a high incidence of TCS among a pediatric neurofibromatosis (NF) cohort. This present study utilizes a population-level database to estimate TCS incidence among pediatric patients with neurofibromatosis types 1 and 2 (NF1, NF2). METHODS: The TriNetX Research Network was queried to identify patients diagnosed with NF and/or TCS before the age of 21. Symptomatic TCS requiring surgical intervention was identified using corresponding procedural codes within 12 months following TCS diagnosis. Odds ratios (OR) were calculated to measure the associations of NF1/NF2 with TCS. RESULTS: 19,426 pediatric NF patients were evaluated (NF1: 18,383, NF2: 1042). The average ages of TCS diagnosis among NF1, NF2, and non-NF patients were 12, 16, and 9 years, respectively. The incidence of TCS was 1.2% in NF1 patients and 7.3% in NF2 patients, compared to 0.074% in the general population. The associations of NF incidence with TCS were significantly increased in both NF1 (OR 16.42; 14.38-18.76) and NF2 (OR 105.58; 83.56-133.40) patients compared to the general population. Symptomatic TCS requiring surgical intervention was not significantly associated with NF1/NF2 patients compared to the general TCS population. CONCLUSION: This analysis demonstrates a high incidence of TCS but delayed intervention in pediatric NF patients. Considering TCS counseling, spinal MRI, and earlier intervention may be warranted for NF patients experiencing musculoskeletal symptomatology.

Thyroid Cancer With Cutaneous Metastases.

Objectives: Thyroid carcinoma with cutaneous metastases is a rare clinical finding. Cutaneous metastases from thyroid carcinoma have been associated with a poor prognosis, but these data are limited to case reports. The exact mechanism of cutaneous metastases from thyroid carcinoma is not clear. Our study aims to report the demographic, clinical, and histologic findings of patients with cutaneous metastases from thyroid carcinoma. Methods: A review was conducted using the Medline/PubMed, Cochrane, and Scopus databases to review literature from inception to May 2023. Data extracted included patient age at diagnosis of cutaneous metastases, patient sex, thyroid carcinoma histotype, location of metastases, the time interval between diagnoses of thyroid carcinoma and cutaneous metastases, and overall survival (OS) from the time of cutaneous metastases. Results: One hundred thirty-six patients were identified and 75 were female. The most common types of thyroid carcinoma with cutaneous metastases were papillary (47.79%), followed by follicular (30.15%), and medullary (11.03%). In addition, 11 cases of anaplastic carcinoma, 2 cases of oncocytic carcinoma, and 2 cases of poorly differentiated thyroid carcinoma were reported. The average age at diagnosis of cutaneous metastases was 63.13 years, and the average time interval between the diagnoses of primary thyroid carcinoma and cutaneous metastases was 48.27 months. The most common location of metastases was the scalp (n = 48). Other common locations included the neck, chest, and face. The OS after diagnosis of metastases was only available in 34 patients with an average of 13.07 months. Of these 34 cases, 10 were medullary, 10 were papillary, 9 were anaplastic, and 5 had follicular carcinoma. Conclusions: This study represents an up-to-date review of the cases of thyroid carcinoma with cutaneous metastases. While cutaneous metastasis remains a rare finding, one needs a high index of suspicion, and their presence portends a poor prognosis.

Current and Emerging Diagnostic, Prognostic, and Predictive Biomarkers in Head and Neck Cancer.

Head and neck cancers (HNC) are a biologically diverse set of cancers that are responsible for over 660,000 new diagnoses each year. Current therapies for HNC require a comprehensive, multimodal approach encompassing resection, radiation therapy, and systemic therapy. With an increased understanding of the mechanisms behind HNC, there has been growing interest in more accurate prognostic indicators of disease, effective post-treatment surveillance, and individualized treatments. This chapter will highlight the commonly used and studied biomarkers in head and neck squamous cell carcinoma.

History of Bariatric Surgery Before Thyroid Surgery: Recommendations for Prevention and Management of Postoperative Hypocalcemia.

Hypocalcemia following thyroidectomy is a common and potentially life-threatening complication. It is caused by intraoperative injury to the parathyroid glands or their blood supply. Although several studies have shown that patients with a prior history of bariatric surgery may be at an increased risk for hypocalcemia after thyroidectomy, no clear recommendations exist for preventing and managing this condition in this population. This paper highlights the significance of understanding this risk and of obtaining a history of prior bariatric surgery before thyroidectomy. We propose concise recommendations for preventing and managing hypocalcemia following thyroidectomy in patients with a history of bariatric surgery.

The COVID-19 Applicant: The Rise of Twitter Among Matched Neurosurgery Applicants.

INTRODUCTION: Social media is becoming increasingly ubiquitous in the professional realm. The coronavirus disease 2019 (COVID-19) pandemic accelerated the shift towards utilizing social media to network and disseminate information, especially via Twitter. Neurosurgery programs have also leveraged Twitter to inform and attract applicants. OBJECTIVE: The purpose of this study is to identify factors influencing the adoption of Twitter by matched neurosurgery applicants before and during the COVID-19 pandemic. METHODS: A list of matched U.S. neurosurgery residents from just before the start of the pandemic (2019-2020) to after the peak of the pandemic (2021-2022), was collated. Twitter was searched to evaluate the presence of a professional account at the time of Electronic Residency Application Service (ERAS) submission. The following demographic variables were collected: gender, medical school, and matched residency institution. RESULTS: Over four application cycles (2019-2022), 897 matched residents were evaluated in the study. Overall, 31.1% had a Twitter account during the time of their residency application. In particular, international medical school graduates were more likely to have a Twitter platform compared to U.S. applicants (50.0% vs. 29.7%; p=.001). The percentage of matched neurosurgery applicants with a Twitter profile significantly increased during the pandemic (21.0% vs. 41.1%; p<.001) with a two-fold increase from 20.0% to 39.7% (p<.001) in U.S. applicants. CONCLUSION: Over the past four years, an increasing number of matched neurosurgery applicants have adopted a Twitter presence during application. Driven by the increasing use of social media and accelerated by the COVID-19 pandemic, Twitter has become an important tool leveraged by during the application process.

Awake craniotomies in the pediatric population: a systematic review.

OBJECTIVE: Awake craniotomy (AC) is employed to maximize tumor resection while preserving neurological function in eloquent brain tissue. This technique is used frequently in adults but remains poorly established in children. Its use has been limited due to concern for children's neuropsychological differences compared with adults and how these differences may interfere with the safety and feasibility of the procedure. Among studies that have reported pediatric ACs, complication rates and anesthetic management vary. This systematic review was performed to comprehensively analyze outcomes and synthesize anesthetic protocols of pediatric ACs. METHODS: The authors followed PRISMA guidelines to extract studies that reported AC in children with intracranial pathologies. The Medline/PubMed, Ovid, and Embase databases were searched from database inception to 2021, using the terms ("awake") AND ("Pediatric*" OR "child*") AND (("brain" AND "surgery") OR "craniotomy"). Data extracted included patient age, pathology, and anesthetic protocol. Primary outcomes assessed were premature conversion to general anesthesia, intraoperative seizures, completion of monitoring tasks, and postoperative complications. RESULTS: Thirty eligible studies published from 1997 to 2020 were included that described a total of 130 children ranging in age from 7 to 17 years who had undergone AC. Of all patients reported, 59% were male and 70% had left-sided lesions. Procedure indications included the following etiologies: tumors (77.6%), epilepsy (20%), and vascular disorders (2.4%). Four (4.1%) of 98 patients required conversion to general anesthesia due to complications or discomfort during AC. In addition, 8 (7.8%) of 103 patients experienced intraoperative seizures. Furthermore, 19 (20.6%) of 92 patients had difficulty completing monitoring tasks. Postoperative complications occurred in 19 (19.4%) of 98 patients and included aphasia (n = 4), hemiparesis (n = 2), sensory deficit (n = 3), motor deficit (n = 4), or others (n = 6). The most commonly reported anesthetic techniques were asleep-awake-asleep protocols using propofol, remifentanil or fentanyl, a local scalp nerve block, and with or without dexmedetomidine. CONCLUSIONS: The findings of this systematic review suggest the tolerability and safety of ACs in the pediatric population. Although pediatric intracranial pathologies pose etiologies that certainly may benefit from AC, there is a need for surgeons and anesthesiologists to perform individualized risk-benefit analyses due to the risks associated with awake procedures in children. Age-specific, standardized guidelines for preoperative planning, intraoperative mapping, monitoring tasks, and anesthesia protocols will help to continue minimizing complications, while improving tolerability, and streamlining workflow in the treatment of this patient population.

Mental health and substance use disorders in young adults with spina bifida.

OBJECTIVE: Although medical advances have allowed most patients with spina bifida (SB) to survive into adulthood, these patients may have physical impairments, urological complications, infections, and neurocognitive deficits. These factors can cause psychological distress and impact the transition from pediatric to adult care. There remains limited research on mental health disorders (MHDs) and substance use disorders (SUDs) in SB patients during this vulnerable transition period. This study aimed to investigate the 10-year incidence of MHDs and SUDs in 18- to 25-year-old patients with SB. METHODS: TriNetX, a federated de-identified database, was retrospectively queried to identify 18- to 25-year-old patients with SB. The presence of MHDs and SUDs based on ICD-10 codes in SB patients (cohort 1) was analyzed and compared with those of patients without SB (cohort 2). Subgroup analysis was performed on SB patients with hydrocephalus and neurogenic bladder (NB). SB patients were further compared to patients with a spinal cord injury (SCI). RESULTS: After propensity score matching, the authors identified 1494 patients in each cohort. SB patients were more likely to have depression (OR 1.949, 95% CI 1.64-2.317), anxiety (OR 1.603, 95% CI 1.359-1.891), somatoform disorders (OR 2.102, 95% CI 1.052-4.199), and suicidal ideations or attempts and self-harm (OR 1.424, 95% CI 1.014-1.999). The prevalence of attention-deficit/hyperactivity disorder (ADHD) and eating disorders were comparable between cohorts. SB patients also had increased rates of nicotine dependence (OR 1.546, 95% CI 1.22-1.959) but not of alcohol or opioid disorders. In SB patients, the presence of hydrocephalus and NB was not associated with significantly increased rates of any measured MHDs or SUDs. When compared with SCI patients, SB patients were more likely to have anxiety (OR 1.377, 95% CI 1.028-1.845) and ADHD (OR 1.875, 95% CI 1.084-3.242). However, SB patients had lower rates of nicotine dependence (OR 0.682, 95% CI 0.482-0.963) and opioid-related disorders (OR 0.434, 95% CI 0.223-0.845). SB and SCI patients shared similar rates of depression, suicidal ideations or attempts and self-harm, and alcohol-related disorders. CONCLUSIONS: Young adults with SB have higher prevalence rates of MHDs and SUDs compared with the general population. Therefore, incorporation of mental health and substance use management is critical to facilitate transition to adulthood.

Female Neurosurgery Residency Program Directors in the United States: A Cross-sectional Descriptive Analysis.

BACKGROUND: The residency program director (PD) position is a valued leadership appointment in academic medicine. PDs are responsible for the success of their program and its residents. The objective of this study is to provide a cross-sectional analysis of baseline demographics and academic backgrounds of current neurosurgery program directors. METHODS: Data was compiled on neurosurgery PDs and their residency programs, as of the end of May 2021, using publicly available resources including Doximity, FREIDA, and Healthgrades. The Mann-Whitney and Fisher exact tests were used for statistical analysis. RESULTS: Of 113 PDs identified, 91.15% are male (P < 0.01). The majority of PDs (88.5%) received their medical degrees from U.S. medical schools. The average age of current PDs is 54 years, and the average age at appointment was 48 years. Compared to their male counterparts, female PDs are more likely to be younger at appointment (41 vs. 48 years; P = 0.001) and while holding the same position (45 vs. 55 years; P = 0.001). As a result, female PDs experience less time to appointment after residency (8.6 years vs. 14.7 years, P = 0.013). There are no significant differences regarding the gender of the PD and university affiliation, current appointment, completion of a fellowship, and resident gender ratios. CONCLUSIONS: The position of neurosurgery residency PD is dominated by fellowship-trained men in their late 40s to 50s. The gender ratio of neurosurgery residents is consistent with the underrepresentation of women in this position. With increasing female representation in neurosurgery, more women may assume this leadership position and begin to hasten the gender balance.

Pregnancy in spina bifida patients: a comparative analysis of peripartum procedures and complications.

PURPOSE: Spina bifida (SB) is caused by a failure in neural tube closure that can present with lower extremity sensory deficits, paralysis, and hydrocephalus. Medical advances have allowed increased pregnancies among SB patients, but management and pregnancy-associated complications have not been thoroughly investigated. The objective is to delineate peripartum procedures and complications in patients with SB. METHODS: A national de-identified database, TriNetX, was retrospectively queried to evaluate pregnant SB patients and the general population. Procedures and complications were investigated using corresponding ICD-10 and CPT codes within 1 year of pregnancy diagnosis. RESULTS: 11,405 SB patients were identified and compared to 9,269,084 non-SB patients. SB patients were significantly more likely to undergo cesarean delivery (1.200; 95% CI [1.133-1.271]) and less likely to receive neuraxial analgesia (0.406; 95% CI [0.383-0.431]). Additionally, patients with SB had an increased risk of seizures (3.922; 95% CI [3.529-4.360]) and venous thromboembolism (VTE) (3.490; 95% CI [3.070-3.969]). Risks of preeclampsia and hemorrhage were comparable. SB patients with hydrocephalus and Chiari malformation type 1 (CM-1) or type 2 (CM-2) were compared to patients without these comorbid conditions. This sub-group analysis showed a significantly increased risk of having cesarean deliveries (SB with hydrocephalus: 12.55%, S.B. with CM-1 or CM-2: 12.81% vs. SB without hydrocephalus or CM, 6.16%) and VTE (3.74%, 2.43% vs. 0.81%). There were also increased risks of hemorrhage and seizures and decreased use of neuraxial analgesia, but the sample size was insufficient. CONCLUSION: SB patients were more likely to undergo cesarean section and exhibit peripartum complications compared to those without SB.

Pregnancy and Childbirth in Women With Meningioma.

Background Ten percent of women of childbearing age have histologically confirmed meningioma. To date, little is known regarding pregnancy-related outcomes for women with meningioma. Methods We used a de-identified database network (TriNetX's Research Network, https://trinetx.com/) to gather information on pregnant patients with meningioma (cohort 1) versus pregnant patients without meningioma (cohort 2). The primary outcome of interest included the impact of meningioma on mortality at one year. Secondary endpoints included ectopic or molar pregnancy, cesarean section, abortion, preterm labor, depression, pre-eclampsia/eclampsia, and craniotomy. Odds ratios (OR) with 95% confidence intervals (CI) were used to measure levels of association between each cohort and the outcomes of interest. Results A total of 1,739 patients were identified in each cohort following propensity-score matching. Mortality was seen in 23 patients (1.32%) in cohort 1 versus 26 patients (1.41%) in cohort 2 (OR 0.88, 95% CI {0.50, 1.55}, p=0.66). Ectopic/ molar pregnancy was seen in 31 (1.78%) versus 42 (2.42%) patients in cohorts 1 and 2, respectively (OR 0.73, 95% CI {0.046,1.17}, p=0.19). Cesarean section was seen in 126 (7.25%) versus 164 (9.43%) patients, respectively (OR 0.75, 95% CI {0.59,0.97}, p=0.020). Abortion was seen in 128 (7.36%) versus 183 (10.52%) patients, respectively (OR 0.68, 95% CI {0.53,0.86}, p=0.0011). Preterm labor was seen in 75 (4.31%) versus 119 (6.84%) patients, respectively (OR 0.61, 95% CI {0.46,0.83}, p=0.0012). Depression was seen in 258 (14.84%) versus 270 (15.53%) patients, respectively (OR 0.95, 95% CI {0.79,1.14}, p=0.57). Pre-eclampsia/eclampsia was seen in 3.11% versus 5.52% patients, respectively (OR 0.55, 95% CI {0.39,0.77}, p=0.0005). Craniotomy was seen in 74 (4.26%) versus 0 (0%) patients in cohort 1 and cohort 2, respectively. Conclusion Patients with meningioma were not at higher risk for pregnancy complications, including ectopic/molar pregnancy, cesarean section, abortion, preterm labor, pre-eclampsia/eclampsia, and mortality, compared to their non-meningioma counterparts. Still, coordinated care by neurosurgical and obstetrical providers may benefit women with meningiomas who are planning for pregnancy or are currently pregnant.

Immune Thrombocytopenic Purpura and Intracerebral Hemorrhage, Incidence, and Mortality.

INTRODUCTION: Intracerebral hemorrhage (ICH) is a devastating complication of immune thrombocytopenic purpura (ITP). Using a large database, we sought to determine its incidence and mortality. METHODS: We used a de-identified database (TriNetX) to gather information on patients with ITP with subsequent ICH (cohort 1), propensity score-matched with patients with ITP and no ICH (cohort 2). Primary endpoint was mortality, with secondary endpoints of percutaneous endoscopic gastrostomy (PEG) placement, craniotomy, palliative care encounters, intensive care unit (ICU) management, seizure, falls, pulmonary embolism (PE), myocardial infarction (MI), deep venous thrombosis (DVT), ischemic stroke (IS), and other venous embolism and thrombosis (VTE). RESULTS: Incidence of ICH in patients with ITP was 1.540% in all ages, and 0.774% in those under age 18. After matching, 942 patients from each cohort were identified. Mean age was 58.3 years versus 61.2 years in cohort 1 and 2, respectively. Mortality rate was 34.076% vs. 20.17% (p <0.0001, OR 2.046 with 95% CI 1.661,2.520) at five years. Thirty-day survival was 83.46% vs. 95.17% (p<0.0001), and 365-day survival 68.59% vs. 85.33% (p<0.0001). PEG placement was seen in 21 (2.229%) patients in cohort 1, and less than 10 patients (<1.062%) in cohort 2 (p<0.0464). 2.442% vs. 0% underwent craniotomy (p<0.0001), palliative care was involved in 15.711% vs. 7.962% (p<0.0001), ICU care was seen in 27.389% vs. 11.783% (p<0.0001), with a mean ICU stay of 8.075 vs. 5.812 days (p=0.0537). 6.582% vs. 3.715% had PE (p=0.0049), 7.643% vs. 7.113% experienced MI (p=0.6595), 9.236% vs. 4.883% had DVTs (p=0.0002), 23.673% vs. 5.732% had seizures (p<0.0001), 9.023% vs. 6.582% suffered falls (p=0.0482), 7.537% vs. 3.503% suffered IS (p<0.0001), and 15.074% vs. 8.174% experienced other VTE (p<0.0001). CONCLUSION: ICH occurs in approximately 1.54% of ITP patients, and is associated with a 34% mortality rate, increased PEG tube placement rates, palliative care involvement, ICU care, craniotomy, PE, IS, DVT, seizures, and falls.

COVID-19 reinfection: the role of natural immunity, vaccines, and variants.

The COVID-19 pandemic has altered innumerable lives. Although recent mass vaccinations offer a glimmer of hope, the rising death toll and new variants continue to dominate the current scenario. As we begin to understand more about SARS-CoV-2 infections, the territory of reinfections with COVID-19 remains unexplored. In this review, we will discuss several aspects of reinfection: (a) How is COVID-19 reinfection characterized? (b) Does prior literature differentiate between reinfection and reactivation? (c) What SARS-CoV-2 strains do the vaccines target and can they protect against new strains? Larger and longer timeline studies are needed to understand reinfection risks. With the ongoing distribution of the SARS-CoV-2 vaccines to provide protection, the understanding of the possibility for SARS-CoV-2 reinfection remains critical. Abbreviations CDC: Centers for Disease ControlSARS-CoV-2: Severe acute respiratory syndrome coronavirus 2COVID-19: Coronavirus disease 2019RT-PCR: Reverse Transcription Polymerase Chain ReactionPASC: Post-Acute Sequelae of SARS-CoV-2 infection.

Deciphering the mechanism of O2 reduction with electronically tunable non-heme iron enzyme model complexes.

A homologous series of electronically tuned 2,2',2''-nitrilotris(N-arylacetamide) pre-ligands (H3LR ) were prepared (R = NO2, CN, CF3, F, Cl, Br, Et, Me, H, OMe, NMe2) and some of their corresponding Fe and Zn species synthesized. The iron complexes react rapidly with O2, the final products of which are diferric mu-oxo bridged species. The crystal structure of the oxidized product obtained from DMA solutions contain a structural motif found in some diiron proteins. The mechanism of iron mediated O2 reduction was explored to the extent that allowed us to construct an empirically consistent rate law. A Hammett plot was constructed that enabled insightful information into the rate-determining step and hence allows for a differentiation between two kinetically equivalent O2 reduction mechanisms.