Utility of Targeted Positron Emission Tomography Imaging to Predict Schwannoma Growth in a Murine Tumor Model.

OBJECTIVE: To identify if targeted positron emission tomography (PET) imaging with radiolabeled antibodies can predict tumor growth rate and ultimate tumor size in a murine flank schwannoma model. STUDY DESIGN: Animal research study. METHODS: Rat schwannoma cells were cultured and implanted into 40 athymic nude mice. Once tumors reached 5 mm in diameter, 30 mice were injected with zirconium-89 labeled antibodies (HER2/Neu, vascular endothelial growth factor receptor 2 (VEGFR2), or IgG isotype). PET/CT was performed, and standardized uptake values (SUV) were recorded. Tumors were serially measured until mice were sacrificed per IACUC protocol. Statistical analysis was performed to measure correlations between SUV values, tumor size, and growth. RESULTS: Mean tumor sizes in mm3 on Day 0 were 144 ± 162 for anti-HER2/Neu, 212 ± 247 for anti-VEGFR2, and 172 ± 204 for IgG isotype groups respectively. Mean growth rates in mm3 /day were 531 ± 250 for HER2, 584 ± 188 for VEGFR2, and 416 ± 163 for the IgG isotype group. For both initial tumor size and growth rates, there was no significant difference between groups. There were significant correlations between maximum tumor volume and both the SUV max in the HER2 group (p = 0.0218, R2 = 0.5020), and we observed significant correlations between growth rate, and SUV values (p = 0.0156, R2 = 0.5394). Respectively, in the anti-VEGFR2 group, there were no significant correlations. CONCLUSION: In a murine schwannoma model, immunotargeted PET imaging with anti-HER2/Neu antibodies predicted tumor growth rate and final tumor size. Laryngoscope, 134:1372-1380, 2024.

Metformin Reduces Tumor Growth in a Murine Flank Schwannoma Model.

HYPOTHESIS: Metformin and aspirin reduce vestibular schwannoma (VS) growth. BACKGROUND: There have been reported associations between patients with VS prescribed metformin and decreased tumor volumetric growth. Aspirin has also been associated with decreased VS growth in animal studies. METHODS: Rat schwannoma cell lines were grown and implanted into 50 athymic nude mice. Tumors were grown to 5 mm, and then mice were injected with either low- or high-dose metformin, aspirin, or saline daily. Tumors were measured until 14 days elapsed or mice demonstrated symptoms such as ulceration, inability to walk, or passed away. RESULTS: There were no significant differences in day 0 tumor sizes between the control and the treatment groups ( p = 0.73). In the low-dose, but not high-dose groups, day 7 volumes were significantly different for both metformin ( p = 0.04) and aspirin ( p = 0.02) compared with placebo. Mean tumor growth rates were 126.6 ± 65.6 mm 3 /day for saline compared with 73.7 ± 29.5 mm 3 /day for low-dose metformin ( p = 0.03) and 68.7 ± 34.8 mm 3 /day for low-dose aspirin ( p = 0.016). There were no significant differences in tumor sizes ( p = 0.59) or growth rates ( p = 0.75) between low-dose metformin and aspirin groups. Low-dose groups had treatment stopped at 14 days, with continued monitoring demonstrating significant increases in tumor growth off treatment for both aspirin ( p = 0.006) and metformin ( p = 0.048). CONCLUSIONS: Metformin treatment significantly reduced VS growth to a similar level as aspirin. Furthermore, when removing both metformin and aspirin treatment, tumor growth significantly increased.

Cochlear implantation after deafness from Pasteurella multocida meningitis.

A woman in her late 40s who works as a veterinary technician represented to the emergency department with increasing headache, confusion, neck stiffness, subjective fevers and distorted hearing 2 days after diagnosis of viral infection at an outside emergency department.Diagnosis of Pasteurella multocida was made from blood cultures and lumbar puncture. Intravenous ceftriaxone was administered for 21 days. By the time of resolution of acute meningitis, she had become completely deaf bilaterally. MRI revealed faint early ossification/possible labyrinthitis ossificans of the basal cochlea, which was confirmed on surgical exploration during the placement of cochlear implants bilaterally 42 days later. We discuss how the atypical features of this infection lead to diagnostic delay and high morbidity, the unique imaging/surgical findings resulting from the infection, and the clinical utility of early and bilateral cochlear implantation in this and similar cases.

PAR-CLIP: A Method for Transcriptome-Wide Identification of RNA Binding Protein Interaction Sites.

During post-transcriptional gene regulation (PTGR), RNA binding proteins (RBPs) interact with all classes of RNA to control RNA maturation, stability, transport, and translation. Here, we describe Photoactivatable-Ribonucleoside-Enhanced Crosslinking and Immunoprecipitation (PAR-CLIP), a transcriptome-scale method for identifying RBP binding sites on target RNAs with nucleotide-level resolution. This method is readily applicable to any protein directly contacting RNA, including RBPs that are predicted to bind in a sequence- or structure-dependent manner at discrete RNA recognition elements (RREs), and those that are thought to bind transiently, such as RNA polymerases or helicases.

Ambulatory Surgery vs Overnight Observation for Total Thyroidectomy: Cost Analysis and Outcomes.

OBJECTIVE: To compare financial impact between patients undergoing ambulatory (same-day discharge) vs overnight admission after total thyroidectomy while showing associated surgical outcomes. STUDY DESIGN: Retrospective review. SETTING: University of Alabama at Birmingham Medical Center from October 2011 and July 2017. METHODS: Patients undergoing total thyroidectomy without concurrent procedures were selected for review. Demographics, comorbidities, admission status, postoperative outcomes including minor and major complications, charges, and costs were collected. Admission status was categorized as inpatient (admission to hospital ≥1 night) or outpatient (discharged from the postoperative recovery unit). Costs were obtained from all related hospital, clinic, and emergency department visits at the University of Alabama at Birmingham within 30 days of the original surgery. After statistical analysis, outcomes and costs were compared between inpatient and outpatient total thyroidectomy patients. RESULTS: Of 870 total thyroidectomy patients included for analysis, 367 (42.2%) met outpatient criteria. A total of 169 patients (19.4%) had a complication, and only hypocalcemia occurred significantly more in the inpatient group (14.3% vs 9.26%; P < .05). No complications occurred more frequently in the outpatient population. There were no mortalities. There was a statistically significant difference between the total cost of inpatient and outpatient thyroidectomies, with outpatient surgery costing on average $2367.27 less per patient (P < .0001). CONCLUSION: Outpatient total thyroidectomy can lead to cost reduction in highly selected patients who have few comorbidities while remaining safe for the patient.

Postoperative Opioid Use in Rhinoplasty Procedures: A Standardized Regimen.

The objective of this study was to create a standardized regimen for preoperative and postoperative analgesic prescribing patterns in rhinoplasty. A prospective study including patients (n = 35) undergoing rhinoplasty by a single surgeon at a tertiary hospital was conducted. Patients were enrolled in this study from August 2018 to November 2019. Patients then completed a diary documenting pain scores and analgesic use for 14 days postoperatively. Patient demographics, complications, rhinoplasty technique performed, and medical history were noted. At the second postoperative clinic visit, the diaries were submitted and pill counts were conducted to ensure accuracy. A total of 23 patients completed this study. The average age of the cohort was 39.07 ± 15.01 years, and 48% were females. The mean number of opioids consumed was 6.15 ± 4.85 pills (range: 0-18). Females consumed an average of 7.2 ± 5.2 pills and males consumed 4.5 ± 3.96 pills. The mean number of acetaminophen and ibuprofen tablets consumed were 7.48 ± 8.52 pills (range: 0-36) and 10.83 ± 10.99 pills (range 0-39), respectively. No postoperative nosebleeds were reported. Males had significantly higher pain scores than females on postoperative days 1 to 8. The mean pain score for postoperative days 8 to 14 was less than 1. Linear regression analysis showed that there was no association between the rhinoplasty technique used and the number of opioids consumed. Rhinoplasty is typically associated with mild pain even when osteotomies are included with the procedure. Our results suggest that surgeons can limit rhinoplasty opioid prescriptions to around seven pills and achieve sufficient pain control in most patients. Preoperative counseling suggesting a low postoperative pain level and the encouragement of nonsteroidal anti-inflammatory drug use will help reduce the risk and misuse of opioid prescriptions.

DND1 maintains germline stem cells via recruitment of the CCR4-NOT complex to target mRNAs.

The vertebrate-conserved RNA-binding protein DND1 is required for the survival of primordial germ cells (PGCs), as well as the suppression of germ cell tumours in mice. Here we show that in mice DND1 binds a UU(A/U) trinucleotide motif predominantly in the 3' untranslated regions of mRNA, and destabilizes target mRNAs through direct recruitment of the CCR4-NOT deadenylase complex. Transcriptomic analysis reveals that the extent of suppression is dependent on the number of DND1-binding sites. This DND1-dependent mRNA destabilization is required for the survival of mouse PGCs and spermatogonial stem cells by suppressing apoptosis. The spectrum of target RNAs includes positive regulators of apoptosis and inflammation, and modulators of signalling pathways that regulate stem-cell pluripotency, including the TGFß superfamily, all of which are aberrantly elevated in DND1-deficient PGCs. We propose that the induction of the post-transcriptional suppressor DND1 synergizes with concurrent transcriptional changes to ensure precise developmental transitions during cellular differentiation and maintenance of the germ line.

PAR-CLIP: A Method for Transcriptome-Wide Identification of RNA Binding Protein Interaction Sites.

During post-transcriptional gene regulation (PTGR), RNA binding proteins (RBPs) interact with all classes of RNA to control RNA maturation, stability, transport, and translation. Here, we describe Photoactivatable-Ribonucleoside-Enhanced Crosslinking and Immunoprecipitation (PAR-CLIP), a transcriptome-scale method for identifying RBP binding sites on target RNAs with nucleotide-level resolution. This method is readily applicable to any protein directly contacting RNA, including RBPs that are predicted to bind in a sequence- or structure-dependent manner at discrete RNA recognition elements (RREs), and those that are thought to bind transiently, such as RNA polymerases or helicases.

Biochemical isolation of Argonaute protein complexes by Ago-APP.

During microRNA (miRNA)-guided gene silencing, Argonaute (Ago) proteins interact with a member of the TNRC6/GW protein family. Here we used a short GW protein-derived peptide fused to GST and demonstrate that it binds to Ago proteins with high affinity. This allows for the simultaneous isolation of all Ago protein complexes expressed in diverse species to identify associated proteins, small RNAs, or target mRNAs. We refer to our method as "Ago protein Affinity Purification by Peptides" (Ago-APP). Furthermore, expression of this peptide competes for endogenous TNRC6 proteins, leading to global inhibition of miRNA function in mammalian cells.

The role of miRNA in inflammation and autoimmunity.

miRNAs are small non-coding RNA molecules that modulate the expression of multiple protein-encoding genes at the post-transcriptional level. They have recently been recognized as powerful regulators of numerous genes and pathways in the pathogenesis of inflammatory and autoimmune diseases. The targets of most miRNAs remain unknown and their roles in biological processes such as cell differentiation, proliferation, and death (apoptosis) are not clearly understood. In this review we will discuss how certain candidate miRNAs affect inflammatory and immune mediated diseases by regulating their cellular and molecular targets. We focused the influence of gender and sex hormones on miRNA. We believe that understanding the role of miRNAs could shed light on the cause and progression of many inflammatory and autoimmune diseases and eventually lay the groundwork for therapeutic options.