Maxillary interim obturator prosthesis fabrication for a patient with limited mouth opening with a digital approach: A clinical report

Squamous cell carcinoma is a common malignant condition affecting the oral cavity and may involve the surrounding maxillofacial regions. Treatment commonly involves resection of the tumor, followed by prosthetic rehabilitation of the resection defect. This clinical report presents a 62-year-old Asian male patient who had previously undergone surgical resection, resulting in a post-surgical Aramany Class II maxillary defect. The patient's medical history included severe trismus, characterized by restricted mouth opening, as well as a diagnosis of maxillary sinus verrucous squamous cell carcinoma. This report provides a comprehensive account of the rapid fabrication of an interim obturator using digitally assisted dentistry techniques.

Assessment of TSPAN Expression Profile and Their Role in the VSCC Prognosis

The role and prognostic value of tetraspanins (TSPANs) in vulvar squamous cell carcinoma (VSCC) remain poorly understood. We sought to primarily determine, at both the molecular and tissue level, the expression profile of the TSPANs CD9, CD63, CD81, and CD82 in archived VSCC samples (n = 117) and further investigate their clinical relevance as prognostic markers. Our studies led us to identify CD63 as the most highly expressed TSPAN, at the gene and protein levels. Multicomparison studies also revealed that the expression of CD9 was associated with tumor size, whereas CD63 upregulation was associated with histological diagnosis and vascular invasion. Moreover, low expression of CD81 and CD82 was associated with worse prognosis. To determine the role of TSPANs in VSCC at the cellular level, we assessed the mRNA levels of CD63 and CD82 in established metastatic (SW962) and non-metastatic (SW954) VSCC human cell lines. CD82 was found to be downregulated in SW962 cells, thus supporting its metastasis suppressor role. However, CD63 was significantly upregulated in both cell lines. Silencing of CD63 by siRNA led to a significant decrease in proliferation of both SW954 and SW962. Furthermore, in SW962 particularly, CD63-siRNA also remarkably inhibited cell migration. Altogether, our data suggest that the differential expression of TSPANs represents an important feature for prognosis of VSCC patients and indicates that CD63 and CD82 are likely potential therapeutic targets in VSCC.

Zn2+ entry through the mitochondrial calcium uniporter is a critical contributor to mitochondrial dysfunction and neurodegeneration

Excitotoxic Ca²⁺ accumulation contributes to ischemic neurodegeneration, and Ca²⁺ can enter the mitochondria through the mitochondrial calcium uniporter (MCU) to promote mitochondrial dysfunction. Yet, Ca²⁺-targeted therapies have met limited success. A growing body of evidence has highlighted the underappreciated importance of Zn²⁺, which also accumulates in neurons after ischemia and can induce mitochondrial dysfunction and cell death. While studies have indicated that Zn²⁺ can also enter the mitochondria through the MCU, the specificity of the pore's role in Zn²⁺-triggered injury is still debated. Present studies use recently available MCU knockout mice to examine how the deletion of this channel impacts deleterious effects of cytosolic Zn²⁺ loading. In cultured cortical neurons from MCU knockout mice, we find significantly reduced mitochondrial Zn²⁺ accumulation. Correspondingly, these neurons were protected from both acute and delayed Zn²⁺-triggered mitochondrial dysfunction, including mitochondrial reactive oxygen species generation, depolarization, swelling and inhibition of respiration. Furthermore, when toxic extramitochondrial effects of Ca²⁺ entry were moderated, both cultured neurons (exposed to Zn²⁺) and CA1 neurons of hippocampal slices (subjected to prolonged oxygen glucose deprivation to model ischemia) from MCU knockout mice displayed decreased neurodegeneration. Finally, to examine the therapeutic applicability of these findings, we added an MCU blocker after toxic Zn²⁺ exposure in wildtype neurons (to induce post-insult MCU blockade). This significantly attenuated the delayed evolution of both mitochondrial dysfunction and neurotoxicity. These data-combining both genetic and pharmacologic tools-support the hypothesis that Zn²⁺ entry through the MCU is a critical contributor to ischemic neurodegeneration that could be targeted for neuroprotection.

Zn2+-induced disruption of neuronal mitochondrial function: Synergism with Ca2+, critical dependence upon cytosolic Zn2+ buffering, and contributions to neuronal injury

Excitotoxic Zn²⁺ and Ca²⁺ accumulation contributes to neuronal injury after ischemia or prolonged seizures. Synaptically released Zn²⁺ can enter postsynaptic neurons via routes including voltage sensitive Ca²⁺ channels (VSCC), and, more rapidly, through Ca²⁺ permeable AMPA channels. There are also intracellular Zn²⁺ binding proteins which can either buffer neuronal Zn²⁺ influx or release bound Zn²⁺ into the cytosol during pathologic conditions. Studies in culture highlight mitochondria as possible targets of Zn²⁺; cytosolic Zn²⁺ can enter mitochondria and induce effects including loss of mitochondrial membrane potential (ΔΨ_m), mitochondrial swelling, and reactive oxygen species (ROS) generation. While brief (5 min) neuronal depolarization (to activate VSCC) in the presence of 300 μM Zn²⁺ causes substantial delayed neurodegeneration, it only mildly impacts acute mitochondrial function, raising questions as to contributions of Zn²⁺-induced mitochondrial dysfunction to neuronal injury. Using brief high (90 mM) K⁺/Zn²⁺ exposures to mimic neuronal depolarization and extracellular Zn²⁺ accumulation as may accompany ischemia in vivo, we examined effects of disrupted cytosolic Zn²⁺ buffering and/or the presence of Ca²⁺, and made several observations: 1. Mild disruption of cytosolic Zn²⁺ buffering-while having little effects alone-markedly enhanced mitochondrial Zn²⁺ accumulation and dysfunction (including loss of ∆Ψ_m, ROS generation, swelling and respiratory inhibition) caused by relatively low (10-50 μM) Zn²⁺ with high K⁺. 2. The presence of Ca²⁺ during the Zn²⁺ exposure decreased cytosolic and mitochondrial Zn²⁺ accumulation, but markedly exacerbated the consequent dysfunction. 3. Paralleling effects on mitochondria, disruption of buffering and presence of Ca²⁺ enhanced Zn²⁺-induced neurodegeneration. 4. Zn²⁺ chelation after the high K⁺/Zn²⁺ exposure attenuated both ROS production and neurodegeneration, supporting the potential utility of delayed interventions. Taken together, these data lend credence to the idea that in pathologic states that impair cytosolic Zn²⁺ buffering, slow uptake of Zn²⁺ along with Ca²⁺ into neurons via VSCC can disrupt the mitochondria and induce neurodegeneration.