Utility of positron emission tomography myocardial perfusion imaging for identifying ischemia and guiding treatment in patients with anomalous coronary arteries.

BACKGROUND: The assessment of anomalous coronary arteries (AAOCA) remains controversial without an optimal stress modality for ischemia. We evaluated the value of PET-CT myocardial perfusion imaging in these patients and subsequent management. METHODS AND RESULTS: AAOCA patients (n = 82) undergoing PET-CT from 2015 to 2021 were retrospectively chart reviewed. Multivariable analyses performed to assess relevant clinical and imaging factors associated with ischemia on PET and AAOCA surgery. Key characteristics include mean age 45 ± 20 years, 30 (37%) female, 45 (55%) with chest pain, 19 (23%) anomalous left main coronary artery, 58 (71%) anomalous right coronary artery, 26 (32%) with objective ischemia on PET-CT, and 37 (45%) who underwent AAOCA surgery. Adverse outcomes over mean follow-up of 2.2 ± 1.8 years included one death and two myocardial infarctions. Anomalous left main was independently associated with ischemia on PET-CT, odds ratio (95% confidence intervals) 4.15 (1.31-13.1), P = .006. Chest pain and ischemia on PET-CT were independently associated with and provided incremental prognostic value for surgery, odds ratio 9.73 (2.78-34.0), P < .001 and 6.79 (1.99-23.2), P = .002, respectively. CONCLUSION: Ischemia on PET-CT occurred in a third of our cohort, identifying patients who may benefit from surgery. Larger studies are needed to evaluate the interplay between AAOCA, ischemia by PET and surgery.

Deficient Nucleotide Excision Repair in Squamous Cell Carcinoma Cells.

Squamous cell carcinomas (SCCs) are associated with ultraviolet radiation and multiple genetic changes, but the mechanisms leading to genetic instability are unclear. SCC cell lines were compared to normal keratinocytes for sensitivity to ultraviolet radiation, DNA repair kinetics and DNA repair protein expression. Relative to normal keratinocytes, four SCC cell lines were all variably sensitive to ultraviolet radiation and, except for the SCC25 cell line, were deficient in global repair of cyclobutane pyrimidine dimers, although not 6-4 photoproducts. Impaired DNA repair of cyclobutane pyrimidine dimers was associated with reduced mRNA expression from XPC but not DDB2 genes which each encode key DNA damage recognition proteins. However, levels of XPC or DDB2 proteins or both were variably reduced in repair-deficient SCC cell lines. p53 levels did not correlate with DNA repair activity or with XPC and DDB2 levels, but p63 levels were deficient in cell lines with reduced global repair. Repair-proficient SCC25 cells depleted of p63 lost XPC expression, early global DNA repair activity and UV resistance. These results demonstrate that some SCC cell lines are deficient in global nucleotide excision repair and support a role for p63 as a regulator of nucleotide excision repair in SCCs.

Preventing Complications of Pediatric Tracheostomy Through Standardized Wound Care and Parent Education.

Importance: Pediatric tracheostomy is commonly performed for upper airway obstruction and prolonged mechanical ventilation. Children undergoing tracheostomy typically have multiple chronic medical problems that place them at high risk for readmission and additional complications. Objective: To determine whether the institution of a postoperative protocol for parent education and wound care with a nurse trained in tracheostomy care decreases the rate of readmission and other complications. Design, Setting, and Participants: A case series and medical record review was conducted of children 18 years and younger who underwent tracheostomy at a tertiary pediatric medical center between January 1, 2009, and December 31, 2014. Intervention: A postoperative tracheostomy care and education protocol. Main Outcomes and Measures: Overall 30-day readmission rate, 30-day tracheostomy-related readmission rate, tracheostomy wound complications, and additional factors that may have affected readmission rates and wound complications (age at the time of tracheostomy, discharge location, indication for tracheostomy). Results: A total of 191 children (118 boys and 73 girls) were included; of these, 112 participated in the education protocol and 79 children did not. Following institution of the education protocol, there was no decrease in the overall readmission rate (26.8% before the protocol vs 26.6% after the protocol; difference, 0.2%; 95% CI, -12.5% to 13.0%) or in the tracheostomy-related readmission rate (10.1% before the protocol vs 7.1% after the protocol; difference, 3.0%; 95% CI, -5.0% to 11.0%). Overall, 68.6% of readmissions were associated with medical comorbidities (95% CI, 55.9% to 81.3%). There was a significant decrease in tracheostomy-related wound complications after institution of the protocol (31.6% to 17.9%; difference, 13.7%; 95% CI, 1.6% to 26.0%). Multiple logistic regression analysis showed that children who were discharged home were significantly more likely to be readmitted for a tracheostomy-related complication than were patients discharged to an advanced care facility (odds ratio, 14.47; 95% CI, 3.08 to 67.92). Conclusions and Relevance: Tracheostomy care requires expertise for all caregivers and is challenging for people without specialized training. Specialized nursing and education protocols are associated with decreased complications of tracheostomy wounds. Children who are discharged directly to home are at higher risk for readmission compared with children discharged to advanced care facilities. Further development of caregiver education protocols is necessary to continue to reduce readmissions and tracheostomy-related complications.

Visualization of the Supraglottis in Laryngomalacia With 3-Dimensional Pediatric Endoscopy.

IMPORTANCE: The use of 3-dimensional (3D) endoscopy has been described in the pediatric airway and has been shown to improve visualization of complex airway anatomy. Laryngomalacia is one of the most common airway disorders evaluated in pediatric otolaryngology offices. Whether 3D visualization is superior to standard endoscopy as a means for assessment and surgical management of complex airway anatomy is unclear. OBJECTIVE: To describe a pilot case series using 3D endoscopy to facilitate supraglottoplasty and to assess surgical outcomes. DESIGN, SETTING, AND PARTICIPANTS: A prospective case series was conducted of 11 children undergoing supraglottoplasty from July 1, 2010, to June 31, 2014, at a tertiary care pediatric hospital. Infants and children with symptomatic laryngomalacia were eligible for the study. Follow-up was completed on December 31, 2014, and data were assessed from February 1 to 15, 2015. INTERVENTIONS: Supraglottoplasty performed using 3D endoscopy. MAIN OUTCOMES AND MEASURES: The outcome data collected included length of hospital stay and frequency of complications (ie, aspiration, granuloma formation, supraglottic narrowing, revision surgery, tracheostomy, and gastrostomy). RESULTS: Eleven children were treated for laryngomalacia with supraglottoplasty (6 boys and 5 girls; mean [SD] age, 29 [85] months). Four of these children (36%) also had grade I subglottic stenosis. The 3D endoscope was judged by all participating senior surgeons to improve visualization of the supraglottic anatomy and to permit more precise tissue removal. No complications occurred after the surgery. Hospital stay was found to be an unreliable indicator owing to multiple comorbidities in many children. Worsening of aspiration occurred in 1 child (9%) who subsequently required gastrostomy tube placement. This child demonstrated progressive neurologic impairment and had severe hypotonia and developmental delay. Another child with subglottic stenosis and subglottic cysts required a tracheostomy owing to severe rhinovirus tracheitis. The remaining 9 children (82%) had good outcomes, with a mean follow-up of 14.7 (range, 12-24) months. CONCLUSIONS AND RELEVANCE: The anatomy of the supraglottis in laryngomalacia is better visualized using 3D techniques. Use of 3D endoscopy may allow for more precise tissue removal. The outcomes and complication rates are similar to those of standard 2D techniques. This study provides a platform to begin comparative analysis between 3D and standard 2D techniques.

Rhabdomyosarcoma of the head and neck in children: review and update.

OBJECTIVE: To review the clinical presentation, histology, staging, treatment modalities, and survival for pediatric head and neck rhabdomyosarcoma (non-orbital). STUDY DESIGN: Retrospective chart review at a tertiary pediatric hospital of children treated over 18 years (1996-2014) for primary head and neck non-orbital rhabdomyosarcoma. METHODS: Medical charts were examined for clinical presentation, staging, histology, genetic abnormalities, treatment modalities, recurrence and complications from treatment. RESULTS: Our cohort was 17 children (7 male, 10 female) with rhabdomyosarcoma with a median age of 6.3 years (range <1-19). The majority of tumors were of parameningeal location (13/17) with embryonal histology (11/17). Twenty-nine percent (5/17) demonstrated advanced metastatic disease at initial referral. Fifty-three percent (9/17) had skull base erosion and/or cranial nerve deficits. PET CT scan was performed in 4 patients. The overall survival was 75% for the duration of the study. Primary surgical excision was performed in all 4 patients with nonparameningeal tumors as compared to only 1 patient with a parameningeal tumor. All received chemotherapy and radiotherapy, as none had completely resectable disease. CONCLUSION: Pediatric non-orbital primary rhabdomyosarcoma of the head and neck usually has a rapid onset and presents with advanced disease. Our analysis found that the majority of patients in our series had a cranial neuropathy at presentation, which highlights how advanced the disease is in these patients at presentation. The first mode of surgical intervention should be directed toward biopsy in junction with a metastatic work-up. Primary excision with negative microscopic margins for nonparameningeal rhabdomyosarcoma is ideal to spare radiotherapy but was not achievable in our cohort. The benefits of second-look biopsy after chemotherapy and radiation are still unproven; however, we believe that it was beneficial in two patients in our review for further resection thus decreasing subsequent radiation. Fluorodeoxy-d-glucose positron emission tomography (PET) to evaluate disease post treatment may further define the role for second look surgery.

"OA02" peptide facilitates the precise targeting of paclitaxel-loaded micellar nanoparticles to ovarian cancer in vivo.

Micellar nanoparticles based on linear polyethylene glycol (PEG) block dendritic cholic acids (CA) copolymers (telodendrimers), for the targeted delivery of chemotherapeutic drugs in the treatment of cancers, are reported. The micellar nanoparticles have been decorated with a high-affinity "OA02" peptide against α-3 integrin receptor to improve the tumor-targeting specificity which is overexpressed on the surface of ovarian cancer cells. "Click chemistry" was used to conjugate alkyne-containing OA02 peptide to the azide group at the distal terminus of the PEG chain in a representative PEG(5k)-CA(8) telodendrimer (micelle-forming unit). The conjugation of OA02 peptide had negligible influence on the physicochemical properties of PEG(5k)-CA(8) nanoparticles and as hypothesized, OA02 peptide dramatically enhanced the uptake efficiency of PEG(5k)-CA(8) nanoparticles (NP) in SKOV-3 and ES-2 ovarian cancer cells via receptor-mediated endocytosis, but not in α-3 integrin-negative K562 leukemia cells. When loaded with paclitaxel, OA02-NPs had significantly higher in vitro cytotoxicity against both SKOV-3 and ES-2 ovarian cancer cells as compared with nontargeted nanoparticles. Furthermore, the in vivo biodistribution study showed OA02 peptide greatly facilitated tumor localization and the intracellular uptake of PEG(5k)-CA(8) nanoparticles into ovarian cancer cells as validated in SKOV3-luc tumor-bearing mice. Finally, paclitaxel (PTX)-loaded OA02-NPs exhibited superior antitumor efficacy and lower systemic toxicity profile in nude mice bearing SKOV-3 tumor xenografts, when compared with equivalent doses of nontargeted PTX-NPs as well as clinical paclitaxel formulation (Taxol). Therefore, OA02-targeted telodendrimers loaded with paclitaxel have great potential as a new therapeutic approach for patients with ovarian cancer.

Defective DNA repair and cell cycle arrest in cells expressing Merkel cell polyomavirus T antigen.

The pathways by which Merkel cell polyomavirus (MCV) infection contributes to the formation of Merkel cell carcinomas are important for understanding the pathogenesis of these cancers. We hypothesized that MCV T antigen suppresses normal responses to ultraviolet radiation (UVR)-induced DNA damage. An MCV-infected cell line (MKL-1) exhibited UVR hypersensitivity, impaired repair of DNA lesions and cell cycle arrest after UVR, as well as reduced levels of the DNA damage recognition protein, XPC. When ectopically expressed in uninfected UISO cells, mutant but not wild-type T antigen resulted in loss of repair of UVR-induced cyclobutane pyrimidine dimers and reductions in XPC, p53 and p21 levels, whereas both wild-type and mutant T antigen inhibited cell cycle arrest after UVR. Similarly, only mutant T antigen in normal fibroblasts inhibited DNA repair and XPC expression, while both mutant and wild-type T antigens produced cell cycle dysregulation. Wild-type T antigen expression produced large T, 57 kT and small T antigens while mutant T antigen was only detectable as a truncated large T antigen protein. Expression of wild-type large T antigen but not small T antigen inhibited the G1 checkpoint in UISO cells, but neither wild-type large T nor small T antigens affected DNA repair, suggesting that large T antigen generates cell cycle defects, and when mutated may also impair DNA repair. These results indicate that T antigen expression by MCV can inhibit key responses to UVR-induced DNA damage and suggest that progressive MCV-mediated abrogation of genomic stability may be involved in Merkel cell carcinogenesis.

Well-defined, reversible disulfide cross-linked micelles for on-demand paclitaxel delivery.

To minimize premature release of drugs from their carriers during circulation in the blood stream, we have recently developed reversible disulfide cross-linked micelles (DCMs) that can be triggered to release drug at the tumor site or in cancer cells. We designed and synthesized thiolated linear-dendritic polymers (telodendrimers) by introducing cysteines to the dendritic oligo-lysine backbone of our previously reported telodendrimers comprised of linear polyethylene glycol (PEG) and a dendritic cluster of cholic acids. Reversibly cross-linked micelles were then prepared by the oxidization of thiol groups to disulfide bond in the core of micelles after the self-assembly of thiolated telodendrimers. The DCMs were spherical with a uniform size of 28 nm, and were able to load paclitaxel (PTX) in the core with superior loading capacity up to 35.5% (w/w, drug/micelle). Cross-linking of the micelles within the core reduced their apparent critical micelle concentration and greatly enhanced their stability in non-reductive physiological conditions as well as severe micelle-disrupting conditions. The release of PTX from the DCMs was significantly slower than that from non-cross-linked micelles (NCMs), but can be gradually facilitated by increasing the concentration of reducing agent (glutathione) to an intracellular reductive level. The DCMs demonstrated a longer in vivo blood circulation time, less hemolytic activities, and superior toxicity profiles in nude mice, when compared to NCMs. DCMs were found to be able to preferentially accumulate at the tumor site in nude mice bearing SKOV-3 ovarian cancer xenograft. We also demonstrated that the disulfide cross-linked micellar formulation of PTX (PTX-DCMs) was more efficacious than both free drug and the non-cross-linked formulation of PTX at equivalent doses of PTX in the ovarian cancer xenograft mouse model. The anti-tumor effect of PTX-DCMs can be further enhanced by triggering the release of PTX on-demand by the administration of the FDA approved reducing agent, N-acetylcysteine, after PTX-DCMs have reached the tumor site.

Impaired repair of cyclobutane pyrimidine dimers in human keratinocytes deficient in p53 and p63.

While many p53-deficient cell types are impaired in global genomic nucleotide excision repair of cyclobutane pyrimidine dimers (CPDs), human epidermal keratinocytes expressing human papillomavirus type 16 E6 and E7 are p53 deficient and yet maintain repair of CPD. We hypothesized that the p53 homolog, p63, may participate in governing global repair instead of p53 in keratinocytes. Following ultraviolet radiation (UVR) of E6/E7 keratinocytes, depletion of p63 but not of p73 impaired global genomic repair of CPD relative to control cells. In all cases, repair of pyrimidine(6-4)pyrimidone photoproducts, the other major UVR-induced DNA lesions, was unaffected. In E6/E7 keratinocytes treated with p63 small interfering RNA, reduced global repair of CPD was associated not with reduced levels of messenger RNA-encoding DNA damage recognition proteins but rather with decreased levels of DDB2 and XPC proteins, suggesting that p63 posttranscriptionally regulates levels of these proteins. These results indicate that global repair may be regulated at multiple levels and suggest a novel role for p63 in modulating repair of DNA damage in human keratinocytes. The results may provide insight into mechanisms of genomic stability in epithelia infected with oncogenic human papilloma viruses and may further explain the lack of increased skin cancer incidence in Li-Fraumeni syndrome.