Prevalence of medication related osteonecrosis of the jaw in patients treated with sequential antiresorptive drugs: systematic review and meta-analysis.

BACKGROUND: Antiresorptive drugs (ARD) are associated with a known serious adverse event, known as medication-related osteonecrosis of the jaws (MRONJ). Transition from one ARD to another has become common clinical practice with the advent of more potent or safer agents; however, the influence of sequential antiresorptive therapy as a risk factor for MRONJ has not been established. OBJECTIVES: To investigate the prevalence of MRONJ in oncology or osteoporosis patients treated with two or more sequential ARDs as opposed to a single antiresorptive drug. MATERIAL AND METHODS: Systematic electronic literature searches were conducted using Ovid MEDLINE, Ovid EMBASE, and Cochrane Central Register of Controlled Trials. Two review authors retrieved studies using pre-determined eligibility criteria and conducted quality assessment and data extraction. Fixed or random-effects meta-analysis models were used to summarize relative estimates for prevalence of MRONJ. RESULTS: A total of 483 titles and abstracts were screened, and 18 full texts were retrieved for review. Twelve studies were included in the final qualitative and quantitative synthesis. Random effects meta-analysis models revealed a weighted pooled MRONJ prevalence of 19% (95% CI 10-27%) for sequential pamidronate-zoledronate therapy, 10% (95% CI 3-22%) for sequential ibandronate-zoledronate therapy. Pooled weighted prevalence of MRONJ was 13% (95% CI 3-22%) for sequential bisphosphonate-denosumab therapy while bisphosphonates only was 5% (95% CI 0-9%) and denosumab only was 4% (95% CI 3-5%). CONCLUSIONS: The present systematic review suggests an increased prevalence of MRONJ associated with sequential ARD therapy for pamidronate-zoledronate and bisphosphonate-denosumab administration when compared to single ARD therapy.

Development of a Checklist to Prevent Reconstructive Errors Made By Undergraduate Dental Students.

PURPOSE: To design a checklist in order to reduce the frequency of reconstructive preventable errors (PE) performed by undergraduate dental students at McGill University. MATERIALS AND METHODS: The most common PE occurring at a university dental clinic were identified by three reviewers analyzing the refunded cases, and used to create a preliminary checklist. This checklist was then validated by a panel of dental educators to produce a finalized 20-item checklist. The 20-question checklist was then submitted to students in a cross-sectional survey-based study to evaluate its relevance to undergraduate clinical education needs. RESULTS: As many as 81% of students reported to have forgotten at least one item of the checklist during care of their last patient, and the most forgotten checklist items corresponded to the pretreatment stage. The students also reported that 17 of the 20 items in the checklist were relevant to a considerable extent or highly relevant. CONCLUSION: Common PE identified in the undergraduate clinic could be used to create a checklist of relevant items designed to reduce errors made by students and practitioners performing prosthodontic and reconstructive treatments. However, further studies are required to evaluate the implementation and efficiency of the checklist.

Outcomes for 160 Consecutive Lateral Arm Free Flaps for Head and Neck Reconstruction.

OBJECTIVE: Examine outcomes for lateral arm autologous tissue transfer in head and neck reconstruction. STUDY DESIGN: Retrospective cohort study. SETTING: Tertiary cancer center. METHODS: All patients who underwent traditional lateral arm, extended lateral arm, and lateral forearm flaps for head and neck reconstruction from 2012 to 2022 were assessed. Disabilities of the arm, shoulder, and hand (DASH) was measured. Factors associated with complications and enteral or mixed diet were evaluated by multivariable regression. RESULTS: Among 160 patients followed for a median of 2.3 ± 2.1 years, defects were 54% oral tongue, 18% external, 9% maxilla, 8% buccal mucosa, 9% floor of mouth, and 3% pharynx. Flap types (and median pedicle lengths) were 41% traditional lateral arm (8 cm), 25% extended lateral arm (11.5 cm), and 34% lateral forearm (14 cm). All donor sites were closed primarily; 19.6% and 0% of patients had increased DASH scores 2 and 12 weeks after reconstruction. Major complications occurred in 18.1% of patients, including 6.3% reoperation, 6.9% readmission, 3.7% fistula, and 1.8% flap loss. Complications were independently associated with peripheral vascular disease (odds ratio [OR]: 5.71, 95% confidence interval [CI]: 1.5-21.6, P = .01), pharyngeal defects (OR: 11.3, 95% CI: 1.4-94.5, P = .025), and interposition vein grafts (OR: 3.78, 95% CI: 1.1-13.3, P = .037). CONCLUSION: The lateral arm free flap was safe, versatile, and reliable for head and neck reconstruction with low donor-site morbidity. Complications occurred in a fifth of patients and were associated with peripheral vascular disease, pharyngeal defects, and vein grafts.

Protein Fibrillation under Crowded Conditions.

Protein amyloid fibrils have widespread implications for human health. Over the last twenty years, fibrillation has been studied using a variety of crowding agents to mimic the packed interior of cells or to probe the mechanisms and pathways of the process. We tabulate and review these results by considering three classes of crowding agent: synthetic polymers, osmolytes and other small molecules, and globular proteins. While some patterns are observable for certain crowding agents, the results are highly variable and often depend on the specific pairing of crowder and fibrillating protein.

Outcomes for recurrent oral cavity squamous cell carcinoma.

OBJECTIVES: We sought to determine overall survival (OS), prognostic factors, cost, and functional outcomes after surgery for locally recurrent oral cavity squamous cell carcinoma (OCSCC). MATERIALS AND METHODS: We retrospectively reviewed 399 cases of locally recurrent OCSCC from 1997 to 2011, of which 259 patients were treated with salvage surgery. Survival and prognostic factors were evaluated using univariable and multivariable Cox regression, the Kaplan-Meier method, and the log-rank test. RESULTS: The 5-year OS for patients undergoing surgical salvage, nonsurgical therapy, or supportive care was 44.2%, 1.5%, and 0%, respectively. For patients who underwent surgical salvage, 133 (51%) patients experienced a second recurrence at a median of 17 months. Factors associated with OS included disease-free interval ≤ 6 months (P =.0001), recurrent stage III-IV disease (P <.0001), and prior radiation (P =.0001). Patients with both advanced stage and prior radiation had a 23% 5-year OS, compared with 70% for those with neither risk (P <.001). Functionally, 85% of patients had > 80% speech intelligibility and 81% were able to eat by mouth following salvage surgery. Of the patients who required tracheostomy, 78% were decannulated. The adjusted median hospital and professional charges for patients were $129,696 (range $9,238-$956,818). CONCLUSIONS: Patients with recurrent OCSCC who underwent salvage surgery have favorable functional outcomes with half of alive at 5 years but poorer OS for advanced disease, disease-free interval ≤ 6 months, and prior radiation. Additionally, treatment is associated with high cost, and about half of patients ultimately develop another recurrence.

Medication-Related Osteonecrosis of the Jaw in Patients Treated Concurrently with Antiresorptive and Antiangiogenic Agents: Systematic Review and Meta-Analysis.

Introduction: Medication-related osteonecrosis of the jaws (MRONJ) is a known adverse event related to the use of antiresorptive (AR) drugs. More recently, an association between antiangiogenic (AA) drugs and MRONJ has been suggested. This review aimed to investigate the overall prevalence and relative risk of MRONJ in patients treated concurrently with AA and AR agents in comparison with a single AA or AR drug. Methods: A review protocol was registered with PROSPERO (ID: CRD42020214244). A systematic literature search, study selection, quality assessment, and data extraction were carried out following PRISMA guidelines. Random-effects meta-analysis models were used to summarize relative estimates for the outcomes, namely prevalence and relative risk of MRONJ. Exposure variable included type of drug, specifically AA and AR agents administered either concurrently or individually. Results: Eleven studies were included in the final qualitative and quantitative syntheses. The overall pooled weighted prevalence of MRONJ with concurrent AA-AR drugs was 6% (95% CI: 3-8%), compared with 0% (95% CI: 0-0%) for AA only and 5% (95% CI: 0-10%) for AR only. However, high heterogeneity was noted among included studies. Retrospective cohort studies showed a higher pooled prevalence of 13% (95% CI: 10-17%) for concurrent AA-AR therapy. The pooled risk ratio for MRONJ revealed a risk with concurrent AA-AR drugs 2.57 times as high as with AR only (95% CI: 0.84-7.87); however, this difference was not statistically significant. Concurrent AA-AR drugs had a risk for MRONJ 23.74 times as high as with AA only (95% CI: 3.71-151.92). Conclusions: High-quality, representative studies are needed for accurate estimation of relative risk of MRONJ with concurrent AA and AR therapy.

The peripheral neuropathy-linked Trembler and Trembler-J mutant forms of peripheral myelin protein 22 are folding-destabilized.

Dominant mutations in the tetraspan membrane protein peripheral myelin protein 22 (PMP22) are known to result in peripheral neuropathies such as Charcot-Marie-Tooth type 1A (CMT1A) disease via mechanisms that appear to be closely linked to misfolding of PMP22 in the membrane of the endoplasmic reticulum (ER). To characterize the molecular defects in PMP22, we examined the structure and stability of two human disease mutant forms of PMP22 that are also the basis for mouse models of peripheral neuropathies: G150D ( Trembler phenotype) and L16P ( Trembler-J phenotype). Circular dichroism and NMR spectroscopic studies indicated that, when folded, the three-dimensional structures of these disease-linked mutants are similar to that of the folded wild-type protein. However, the folded forms of the mutants were observed to be destabilized relative to the wild-type protein, with the L16P mutant being particularly unstable. The rate of refolding from an unfolded state was observed to be very slow for the wild-type protein, and no refolding was observed for either mutant. These results lead to the hypothesis that ER quality control recognizes the G150D and L16P mutant forms of PMP22 as defective through mechanisms closely related to their conformational instability and/or slow folding. It was also seen that wild-type PMP22 binds Zn(II) and Cu(II) with micromolar affinity, a property that may be important to the stability and function of this protein. Zn(II) was able to rescue the stability defect of the Tr mutant.

Sensory acceptable equivalent doses of ß-phenylethyl isothiocyanate (PEITC) induce cell cycle arrest and retard the growth of p53 mutated oral cancer in vitro and in vivo.

High doses of ß-phenylethyl isothiocyanate (PEITC), a phytochemical in cruciferous vegetables, are not feasible for consumption due to a strong mouth-tingling effect. This study investigated the anti-cancer effect of PEITC at sensory acceptable doses. In vitro, PEITC was selectively toxic to oral cancer cells (CAL-27, FaDu, SCC4, SCC 9, SCC15, SCC25 and TU138), compared to oral keratinocytes (OKF6/TERT2 and NOK/Si). In vivo, 5 and 10 mg kg-1 PEITC, equivalent to human organoleptically acceptable doses, retarded tumor growth and prolonged the survival of mice bearing p53-mutated oral cancer cells - TU138 xenograft. Mechanistically, PEITC induced ROS accumulation, nuclear translocation of p53 and p21 and G1/S cell cycle arrest in vitro; increased p53 and 8-oxo-dG levels; and decreased Ki-67 intense/mild staining ratios without TUNEL changes in vivo. These findings suggested that the sensory acceptable doses of PEITC selectively induced ROS-mediated cell cycle arrest leading to delayed tumor progression and extended survival. PEITC could be a functional ingredient for oral cancer prevention.

Sentinel lymph node biopsy for ocular adnexal melanoma.

BACKGROUND: We sought to update our prior report of findings on sentinel lymph node biopsy (SLNB) and predictors of a positive SLN in patients with conjunctival or eyelid melanoma. METHODS: We reviewed the records of all patients with ocular adnexal melanoma who underwent SLNB at one institution during 2000-2015. We determined rates of positive and false-negative findings on SLNB, primary tumour features correlated with positive findings and rate of nodal recurrence (false-negative event) after negative findings. RESULTS: The study included 51 patients, 31 with conjunctival and 20 with eyelid melanoma. These patients include 30 patients who underwent SLNB during 2000-2008, described in our previous report, and 21 additional patients who underwent SLNB during 2008-2015. There were 30 women and 21 men with median age at SLNB of 62 years (range, 24-83). The nodal basins most commonly sampled were intraparotid (27 patients) and level II (14 patients). Ten patients had positive SLNB findings. Compared to tumours with negative findings, tumours with positive findings had greater median thickness (3.5 mm versus 2.2 mm, p = 0.04), greater median number of mitotic figures (6 versus 2, p = 0.03) and greater incidence of ulceration (80% versus 26%, p = 0.003). Perineural and vascular invasion were not significantly associated with positive findings. There were three false-negative events. Three patients (6%) had temporary marginal mandibular weakness which resolved spontaneously. CONCLUSION: SLNB in patients with ocular adnexal melanoma is safe and identifies nodal micrometastasis in approximately 20% of cases. Histologic features associated with a positive SLN included greater tumour thickness, greater number of mitotic figures and ulceration.

Detection of somatic mutations and HPV in the saliva and plasma of patients with head and neck squamous cell carcinomas.

To explore the potential of tumor-specific DNA as a biomarker for head and neck squamous cell carcinomas (HNSCC), we queried DNA from saliva or plasma of 93 HNSCC patients. We searched for somatic mutations or human papillomavirus genes, collectively referred to as tumor DNA. When both plasma and saliva were tested, tumor DNA was detected in 96% of 47 patients. The fractions of patients with detectable tumor DNA in early- and late-stage disease were 100% (n = 10) and 95% (n = 37), respectively. When segregated by site, tumor DNA was detected in 100% (n = 15), 91% (n = 22), 100% (n = 7), and 100% (n = 3) of patients with tumors of the oral cavity, oropharynx, larynx, and hypopharynx, respectively. In saliva, tumor DNA was found in 100% of patients with oral cavity cancers and in 47 to 70% of patients with cancers of the other sites. In plasma, tumor DNA was found in 80% of patients with oral cavity cancers, and in 86 to 100% of patients with cancers of the other sites. Thus, saliva is preferentially enriched for tumor DNA from the oral cavity, whereas plasma is preferentially enriched for tumor DNA from the other sites. Tumor DNA in saliva was found postsurgically in three patients before clinical diagnosis of recurrence, but in none of the five patients without recurrence. Tumor DNA in the saliva and plasma appears to be a potentially valuable biomarker for detection of HNSCC.

Detection of plasminogen activators in oral cancer by laser capture microdissection combined with zymography.

Plasminogen activation is believed to be critical to the progression of oral squamous cell carcinoma by facilitating matrix degradation during invasion and metastasis, and high levels of urokinase plasminogen activator (uPA) and plasminogen activator (PA) inhibitor-1 (PAI-1) in tumors predict poor disease outcome. We describe the development of a novel method for studying PA in oral cancer that combines the sensitivity and specificity of zymography with the spatial resolution of immunohistochemistry. Laser capture microdissection (LCM) was combined with plasminogen-casein zymography to analyze uPA, tissue PA (tPA), uPA-PAI-1 complexes, and tPA-PAI-1 complexes in 11 tumors and adjacent non-malignant epithelium from squamous cell carcinomas of the tongue, floor of mouth, larynx, and vocal cord. uPA was detectable in all tumor samples analyzed, uPA-PAI-1 complexes in three samples, and tPA in nine. PA was detectable in as little as 0.5 microg protein lysate from microdissected tumors. In all specimens, uPA expression was highly increased in tumor tissue compared to adjacent non-malignant tissue. In conclusion, LCM combined with zymography may be excellently suited for analyzing the prognostic significance and causal involvement of the plasminogen activation system in oral cancer.

Selective uptake and imaging of aptamer- and antibody-conjugated hollow nanospheres targeted to epidermal growth factor receptors overexpressed in head and neck cancer.

The purpose of this study was to compare the binding affinity and selective targeting of aptamer- and antibody-coated hollow gold nanospheres (HAuNS) targeted to epidermal growth factor receptors (EGFR). EGFR-targeting aptamers were conjugated to HAuNS (apt-HAuNS) by attaching a thiol-terminated single-stranded DNA to the HAuNS and then adding the complementary RNA targeted to EGFR. Apt-HAuNS was characterized in terms of size, surface charge, absorption, and number of aptamers per particle. The in vivo pharmacokinetics, in vivo biodistribution, and micro-SPECT/CT imaging of (111)In-labeled apt-HAuNS and anti-EGFR antibody (C225)-conjugated HAuNS were evaluated in nude mice bearing highly malignant human OSC-19 oral tumors. (111)In-labeled PEG-HAuNS was used as a control (n = 5/group). Apt-HAuNS did not have an altered absorbance profile or size (λmax = 800 nm; diameter = 55 nm) compared to C225-HAuNS or PEG-HAuNS. The surface charge became more negative upon conjugation of the aptamer (-51.4 vs -19.0 for PEG-HAuNS and -25.0 for C225-HAuNS). The number of aptamers/particle was ∼250. In vitro cell binding and in vivo biodistribution showed selective binding of the apt-HAuNS to EGFR. µSPECT/CT imaging confirmed that there was more tumor uptake of apt-HAuNS than C225-HAuNS. Aptamer is a promising ligand for image-guided delivery of nanoparticles for treatment of tumor cells overexpressing EGFR.

Noncovalent assembly of targeted carbon nanovectors enables synergistic drug and radiation cancer therapy in vivo.

Current chemotherapeutics are characterized by efficient tumor cell-killing and severe side effects mostly derived from off-target toxicity. Hence targeted delivery of these drugs to tumor cells is actively sought. In an in vitro system, we previously demonstrated that targeted drug delivery to cancer cells overexpressing epidermal growth factor receptor (EGFR+) can be achieved by poly(ethylene glycol)-functionalized carbon nanovectors simply mixed with a drug, paclitaxel, and an antibody that binds to the epidermal growth factor receptor, cetuximab. This construct is unusual in that all three components are assembled through noncovalent interactions. Here we show that this same construct is effective in vivo, enhancing radiotherapy of EGFR+ tumors. This targeted nanovector system has the potential to be a new therapy for head and neck squamous cell carcinomas, deserving of further preclinical development.

Noncovalent functionalization of carbon nanovectors with an antibody enables targeted drug delivery.

Current chemotherapeutics are characterized by efficient tumor cell-killing and severe side effects mostly derived from off-target toxicity. Hence targeted delivery of these drugs to tumor cells is actively sought. We previously demonstrated that poly(ethylene glycol)-functionalized carbon nanovectors are able to sequester paclitaxel, a widely used hydrophobic cancer drug, by simple physisorption and thereby deliver the drug for killing of cancer cells. The cell-killing when these drug-loaded carbon nanoparticles were used was equivalent to when a commercial formulation of paclitaxel was used. Here we show that by further mixing the drug-loaded nanoparticles with Cetuximab, a monoclonal antibody that recognizes the epidermal growth factor receptor (EGFR), paclitaxel is preferentially targeted to EGFR+ tumor cells in vitro. This supports progressing to in vivo studies. Moreover, the construct is unusual in that all three components are assembled through noncovalent interactions. Such noncovalent assembly could enable high-throughput screening of drug/antibody combinations.

Development of an oral cancer recurrence mouse model after surgical resection.

Oral squamous cell carcinomas (OSCC) are frequent epithelial malignancies and afflicted with a poor prognosis. The majority of these cancers are treated with surgical resection and local recurrences are predominantly responsible for a fatal outcome. In order to provide a better understanding of the development of these local recurrences after surgical ablation, we developed an orthotopic floor-of-mouth squamous cell carcinoma murine model, in which local recurrences occur at a high frequency (55%, 8 out of 15 mice) within 6-21 days after microsurgical removal of the primary. Expression of the enhanced green fluorescent protein (eGFP) in the cancer cells allows in this new model to confirm complete surgical resection under the microscope and helps to track repopulating primary tumor cells in the local recurrence by optical imaging. In addition the model resembles all typical features of invasive head and neck cancers including the formation of lymph node metastasis and local infiltration.

Sentinel lymph node biopsy accurately stages the regional lymph nodes for T1-T2 oral squamous cell carcinomas: results of a prospective multi-institutional trial.

PURPOSE: The validity of sentinel lymph node biopsy (SLNB) for T1 or T2, clinically N0, oral cancer was tested by correlation of sentinel node pathologic status with that of nodes within the completion neck dissection. METHODS: This prospective, cooperative group trial involved 25 institutions over a 3-year period. One hundred forty patients with invasive oral cancers, stage T1 and T2, N0 including 95 cancers of the tongue, 26 of the floor of mouth, and 19 other oral cancers were studied. The study excluded lesions with diameter smaller than 6 mm or minimal invasion. Imaging was used to exclude nonpalpable gross nodal disease. Patients underwent injection of the lesion with (99m)Tc-sulfur colloid, nuclear imaging, narrow-exposure SLNB, and completion selective neck dissection. The major end point was the negative-predictive value (NPV) of SLNB. RESULTS: In the 106 SLNBs, which were found to be pathologically and clinically node-negative by routine hematoxylin and eosin stain, 100 patients were found to have no other pathologically positive nodes, corresponding to a NPV of 94%. With additional sectioning and immunohistochemistry, NPV was improved to 96%. In the forty patients with proven cervical metastases, the true-positive rate was 90.2% and was superior for tongue tumors relative to floor of mouth. For T1 lesions, metastases were correctly identified in 100%. CONCLUSION: For T1 or T2 N0 oral squamous cell carcinoma, SLNB with step sectioning and immunohistochemistry, performed by surgeons of mixed experience levels, correctly predicted a pathologically negative neck in 96% of patients (NPV, 96%).

Effective drug delivery, in vitro and in vivo, by carbon-based nanovectors noncovalently loaded with unmodified Paclitaxel.

Many new drugs have low aqueous solubility and high therapeutic efficacy. Paclitaxel (PTX) is a classic example of this type of compound. Here we show that extremely small (<40 nm) hydrophilic carbon clusters (HCCs) that are PEGylated (PEG-HCCs) are effective drug delivery vehicles when simply mixed with paclitaxel. This formulation of PTX sequestered in PEG-HCCs (PTX/PEG-HCCs) is stable for at least 20 weeks. The PTX/PEG-HCCs formulation was as effective as PTX in a clinical formulation in reducing tumor volumes in an orthotopic murine model of oral squamous cell carcinoma. Preliminary toxicity and biodistribution studies suggest that the PEG-HCCs are not acutely toxic and, like many other nanomaterials, are primarily accumulated in the liver and spleen. This work demonstrates that carbon nanomaterials are effective drug delivery vehicles in vivo when noncovalently loaded with an unmodified drug.