Effects of melatonin on dopaminergic neuron development via IP3-mediated mitochondrial Ca2+ regulation in autism spectrum disorder.

Melatonin entrainment of suprachiasmatic nucleus-regulating circadian rhythms is mediated by MT1 and MT2 receptors. Melatonin also has neuroprotective and mitochondrial activating effects, suggesting it may affect neurodevelopment. We studied melatonin's pharmacological effects on autism spectrum disorder (ASD) neuropathology. Deciduous tooth-derived stem cells from children with ASD were used to model neurodevelopmental defects and differentiated into dopaminergic neurons (ASD-DNs) with or without melatonin. Without melatonin, ASD-DNs had reduced neurite outgrowth, mitochondrial dysfunction, lower mitochondrial Ca2+ levels, and Ca2+ accumulation in the endoplasmic reticulum (ER) compared to control DNs from typically developing children-derived stem cells. Melatonin enhanced IP3-dependent Ca2+ release from ER to mitochondria, improving mitochondrial function and neurite outgrowth in ASD-DNs. Luzindole, an MT1/MT2 antagonist, blocked these effects. Thus, melatonin supplementation may improve dopaminergic system development in ASD by modulating mitochondrial Ca2+ homeostasis via MT1/MT2 receptors.

Safety of hydrogel spacers for rectal wall protection in patients with prostate cancer: A retrospective analysis of 200 consecutive cases.

OBJECTIVE: To evaluate the safety and complications of hydrogel spacer implantation. METHODS: This single-center historical cohort study retrospectively analyzed cases of hydrogel spacer implantation between October 2018 and March 2022. The survey items were the rates of possible hydrogel injection implementation, the success rate of hydrogel implantation including asymmetry, higher position, rectal wall infiltration, subcapsular injection, and other adverse events, and width created by the spacer. To investigate the learning curve, 1, 2, and 3 points were assigned to adverse event grades G1, G2, and G3, respectively. Spacer effectiveness obstruction, such as asymmetry was assigned 3 points. A Mann-Whitney U test was performed to assess statistically significant differences. RESULTS: The study included a total of 200 patients with a median (range) age of 70 (44-85) years. In 10 (5%) patients, hydrogel injection implementation was not possible. Of 190 patients who underwent hydrogel spacer placement, 168 (88%) received a satisfactory placement. The median (range) width of hydrogel spacers was 13.1 (4.4-18.7) mm. Spacer asymmetry, higher position, rectal wall infiltration, and prostate subcapsular infiltration occurred in 7 (3.7%), 5 (2.6%), 12 (6.3%), and 1 (0.5%) patients, respectively. G1 and G3 adverse events occurred in 13 (7%) and 4 (2%) patients, respectively. Practitioner #1 who performed the highest number of procedures had significantly (p = 0.04) lower total scores in group B. CONCLUSION: Spacer implantation yielded favorable outcomes with a high percentage of appropriate spacer implantation, and few major complications.

Periodontal disease among older people and its impact on oral health-related quality of life.

OBJECTIVE: The aim of the study was to evaluate the associations between degree of periodontal disease and number of teeth on oral health-related quality of life among older individuals. MATERIAL AND METHODS: Randomly selected 804 participants aged ≥70 derived from two cohorts were included in the analysis. Dental examinations and evaluation of OHRQL using the OHIP-14 (Oral Health Impact Profile-14) were performed. After categorisation of the participants according to the extent of periodontitis in three groups (none, localised with <30% of teeth affected, generalised with ≥30% of teeth affected) and the number of teeth, associations between periodontal status and the number of teeth and the OHIP-14 scores were analysed. Multivariable regression analyses were used taking into account level of periodontitis, number of teeth, age and sex. RESULTS: Among 70-year-old men and women, generalised periodontitis showed an association with poor OHRQL. However, a multivariable analysis failed to demonstrate this association (OR = 1.02, 95% CI: 0.72-1.44). In participants with 1-10 remaining teeth, the OHIP-14 score was significantly increased indicating poor OHRQL, compared with participants with ≥21 remaining teeth (OR = 1.57, 95% CI: 1.13-2.19). Similar findings were observed among women aged 70-92 years. CONCLUSIONS: Periodontitis did not show an association with poor OHRQL, however, a significant association between the number of teeth and poor OHRQL was found.

Identification of Induced Radionuclides Produced from Dental Metals in Proton Beam Therapy for Head and Neck Cancer.

Purpose: To identify the induced radionuclides produced from dental metals in proton beam therapy and investigate the accuracy of the Monte Carlo (MC) simulation by comparing the measured radioactivity. Methods and Materials: Two dental metals of pure titanium and gold-silver-palladium alloy, commonly used in Japan, were used in this study. The dental metal placed at the center of Spread-out Bragg Peak was irradiated by 150-MeV passive scattering proton beam. The gamma rays emitted from the activated dental metals were measured using a high purity germanium (HPGe) detector. The induced radionuclides were identified from the measured gamma-ray energies. Furthermore, the Particle and Heavy Ion Transport code System v.3.24 and DCHAIN were used for the MC simulation. The measured radionuclides and their radioactivity were compared with the simulation results. Results: In the MC simulation for the activated titanium, vanadium-47, with a half-life of 32.6 minutes had the strongest radioactivity among the induced radionuclides. The energy peaks of gamma rays emitted from titanium-51, scandium-43, scandium-44, and annihilation gamma rays were observed for the activated titanium in the HPGe detector. In the MC simulation for the activated gold-silver-palladium alloy, silver-108, with a half-life of 2.4 minutes had the strongest radioactivity. The energy peaks of gamma rays emitted from silver-104, silver-104 m, silver-108, and annihilation gamma rays were observed for the activated gold-silver-palladium alloy in the HPGe detector. Furthermore, the induced radionuclides and their radioactivity in the MC simulation were consistent with the measurement results for both dental metals, except for a few radionuclides. Conclusions: We identify the induced radionuclides produced from 2 dental metals and compared their radioactivity between the measurements and the MC simulation. Although the identification of the induced radionuclides using the MC simulation remains uncertain, the MC simulation can be clinically effective for pre-estimating the induced radionuclides in proton beam therapy.

Influence of the nanostructural characteristics of inorganic fillers on the physical properties of resin cements.

Light-curing resin cements, each comprising one of five different inorganic fillers (non-porous and porous spherical SiO2 particles, irregularly shaped glass and ZrO2 particles, and porous ZrO2 spheres), monomers, and polymerization initiators were prepared to determine the effect of filler morphology on the adhesive strength of the resin cement. The strength of adhesion to a computer-aided design/computer-aided manufacturing (CAD/CAM) resin block was investigated mechanically by measuring the tensile bond strength, flexural strength, and elastic modulus. The resin cement containing sub-micron porous ZrO2 spheres had significantly higher tensile bond strength than the other resin cements. The resin cement containing the porous ZrO2 spheres had markedly lower flexural strength and elastic modulus values than the resin cements containing SiO2 and glass fillers.

TRPV4-mediated Ca2+ deregulation causes mitochondrial dysfunction via the AKT/α-synuclein pathway in dopaminergic neurons.

Mutations in the gene encoding the transient receptor potential vanilloid member 4 (TRPV4), a Ca2+ permeable nonselective cation channel, cause TRPV4-related disorders. TRPV4 is widely expressed in the brain; however, the pathogenesis underlying TRPV4-mediated Ca2+ deregulation in neurodevelopment remains unresolved and an effective therapeutic strategy remains to be established. These issues were addressed by isolating mutant dental pulp stem cells from a tooth donated by a child diagnosed with metatropic dysplasia with neurodevelopmental comorbidities caused by a gain-of-function TRPV4 mutation, c.1855C > T (p.L619F). The mutation was repaired using CRISPR/Cas9 to generate corrected isogenic stem cells. These stem cells were differentiated into dopaminergic neurons and the pharmacological effects of folic acid were examined. In mutant neurons, constitutively elevated cytosolic Ca2+ augmented AKT-mediated α-synuclein (α-syn) induction, resulting in mitochondrial Ca2+ accumulation and dysfunction. The TRPV4 antagonist, AKT inhibitor, or α-syn knockdown, normalizes the mitochondrial Ca2+ levels in mutant neurons, suggesting the importance of mutant TRPV4/Ca2+/AKT-induced α-syn in mitochondrial Ca2+ accumulation. Folic acid was effective in normalizing mitochondrial Ca2+ levels via the transcriptional repression of α-syn and improving mitochondrial reactive oxygen species levels, adenosine triphosphate synthesis, and neurite outgrowth of mutant neurons. This study provides new insights into the neuropathological mechanisms underlying TRPV4-related disorders and related therapeutic strategies.

Dopamine-related oxidative stress and mitochondrial dysfunction in dopaminergic neurons differentiated from deciduous teeth-derived stem cells of children with Down syndrome.

Down syndrome (DS) is one of the common genetic disorders caused by the trisomy of human chromosome 21 (HSA21). Mitochondrial dysfunction and redox imbalance play important roles in DS pathology, and altered dopaminergic regulation has been demonstrated in the brain of individuals with DS. However, the pathological association of these elements is not yet fully understood. In this study, we analyzed dopaminergic neurons (DNs) differentiated from deciduous teeth-derived stem cells of children with DS or healthy control children. As previously observed in the analysis of a single case of DS, compared to controls, patient-derived DNs (DS-DNs) displayed shorter neurite outgrowth and fewer branches, as well as downregulated vesicular monoamine transporter 2 and upregulated dopamine transporter 1, both of which are key regulators of dopamine homeostasis in DNs. In agreement with these expression profiles, DS-DNs accumulated dopamine intracellularly and had increased levels of cellular and mitochondrial reactive oxygen species (ROS). DS-DNs showed downregulation of non-canonical Notch ligand, delta-like 1, which may contribute to dopamine accumulation and increased ROS levels through DAT1 upregulation. Furthermore, DS-DNs showed mitochondrial dysfunction in consistent with lower expression of peroxisome proliferator-activated receptor-gamma coactivator 1 alpha (PGC-1α) and upregulation of a HSA21-encoded negative regulator of PGC-1α, nuclear receptor-interacting protein 1. These results suggest that dysregulated dopamine homeostasis may participate in oxidative stress and mitochondrial dysfunction of the dopaminergic system in DS.

Mitochondrial Calcium-Triggered Oxidative Stress and Developmental Defects in Dopaminergic Neurons Differentiated from Deciduous Teeth-Derived Dental Pulp Stem Cells with MFF Insufficiency.

Mitochondrial fission factor (MFF) is an adapter that targets dynamin-related protein 1 from the cytosol to the mitochondria for fission. Loss-of-function MFF mutations cause encephalopathy due to defective mitochondrial and peroxisomal fission 2 (EMPF2). To elucidate the molecular mechanisms that were involved, we analyzed the functional effects of MFF depletion in deciduous teeth-derived dental pulp stem cells differentiating into dopaminergic neurons (DNs). When treated with MFF-targeting small interfering RNA, DNs showed impaired neurite outgrowth and reduced mitochondrial signals in neurites harboring elongated mitochondria. MFF silencing also caused mitochondrial Ca2+ accumulation through accelerated Ca2+ influx from the endoplasmic reticulum (ER) via the inositol 1,4,5-trisphosphate receptor. Mitochondrial Ca2+ overload led DNs to produce excessive reactive oxygen species (ROS), and downregulated peroxisome proliferator-activated receptor-gamma co-activator-1 alpha (PGC-1α). MFF was co-immunoprecipitated with voltage-dependent anion channel 1, an essential component of the ER-mitochondrial Ca2+ transport system. Folic acid supplementation normalized ROS levels, PGC-1α mediated mitochondrial biogenesis, and neurite outgrowth in MFF depleted DNs, without affecting their mitochondrial morphology or Ca2+ levels. We propose that MFF negatively regulates the mitochondrial Ca2+ influx from the ER. MFF-insufficiency recapitulated the EMPF2 neuropathology with increased oxidative stress and suppressed mitochondrial biogenesis. ROS and mitochondrial biogenesis might be potential therapeutic targets for EMPF2.

Impaired neurite development and mitochondrial dysfunction associated with calcium accumulation in dopaminergic neurons differentiated from the dental pulp stem cells of a patient with metatropic dysplasia.

Transient receptor potential vanilloid member 4 (TRPV4) is a Ca2+ permeable nonselective cation channel, and mutations in the TRPV4 gene cause congenital skeletal dysplasias and peripheral neuropathies. Although TRPV4 is widely expressed in the brain, few studies have assessed the pathogenesis of TRPV4 mutations in the brain. We aimed to elucidate the pathological associations between a specific TRPV4 mutation and neurodevelopmental defects using dopaminergic neurons (DNs) differentiated from dental pulp stem cells (DPSCs). DPSCs were isolated from a patient with metatropic dysplasia and multiple neuropsychiatric symptoms caused by a gain-of-function TRPV4 mutation, c.1855C>T (p.L619F). The mutation was corrected by CRISPR/Cas9 to obtain isogenic control DPSCs. Mutant DPSCs differentiated into DNs without undergoing apoptosis; however, neurite development was significantly impaired in mutant vs. control DNs. Mutant DNs also showed accumulation of mitochondrial Ca2+ and reactive oxygen species, low adenosine triphosphate levels despite a high mitochondrial membrane potential, and lower peroxisome proliferator-activated receptor gamma coactivator 1-alpha expression and mitochondrial content. These results suggested that the persistent Ca2+ entry through the constitutively activated TRPV4 might perturb the adaptive coordination of multiple mitochondrial functions, including oxidative phosphorylation, redox control, and biogenesis, required for dopaminergic circuit development in the brain. Thus, certain mutations in TRPV4 that are associated with skeletal dysplasia might have pathogenic effects on brain development, and mitochondria might be a potential therapeutic target to alleviate the neuropsychiatric symptoms of TRPV4-related diseases.

Proton beam therapy combined with retrograde intra-arterial infusion chemotherapy for an extremely rapid growing recurrent ameloblastic carcinoma: A case report.

Ameloblastic carcinoma (AC) is a very rare malignant odontogenic tumor. Although surgical resection is generally performed, treatment approaches have not been established for recurrent cases. Chemotherapy and radiotherapy are positioned as adjunctive therapies, and few studies investigated definitive non-operative therapy. We present the case of a 71-year-old male with recurrent secondary-type AC arising from the right maxilla, who was treated with proton beam therapy (PBT; 71.4 Gy relative biological effectiveness in 32 fractions) combined with continuous intra-arterial infusion of cisplatin (40 mg/m2) and docetaxel (8 mg/m2). The patient experienced acute grade 3 mucositis, dermatitis and neutropenia, which were resolved within 3 months of treatment. Late adverse events were grade 1 skin atrophy, and grade 2 right optic nerve disorder and retinopathy. After ~8 years of treatment, the patient died from another cause but did not experience any relapse or metastasis during the follow-up period of 94 months. To the best of our knowledge, this is the first report of recurrent AC treated with PBT and intra-arterial infusion chemotherapy without any severe late adverse events. This combination therapy approach may be considered as an effective therapeutic option for inoperable AC.

Cellular motility of Down syndrome gingival fibroblasts is susceptible to impairment by Porphyromonas gingivalis invasion.

BACKGROUND: Severe periodontal breakdown is often associated with Down syndrome (DS); however, the etiology of this condition is not understood fully. Cellular motility of gingival fibroblasts is a critical event for wound healing and regeneration of periodontal tissues. Porphyromonas gingivalis is known to be a periodontal pathogen that invades host cells, contributing to periodontal destruction. In this study, we examined the influence of P. gingivalis infection on the motility of DS gingival fibroblasts (DGFs). METHODS: DGFs and normal gingival fibroblasts (NGFs) were infected with P. gingivalis with type II fimbriae, and cellular motility was evaluated using an in vitro wounding assay. Protein degradation of alpha5beta1-integrin subunits and a migration-regulating signaling molecule, paxillin, were investigated using specific antibodies. The adhesion to and invasion of fibroblasts by P. gingivalis were determined with a colony forming assay. The gene expressions of alpha5beta1-integrin subunits were also quantified using a reverse transcription-polymerase chain reaction method. RESULTS: The cellular motility of DGFs was impaired significantly by P. gingivalis compared to NGFs, and the former were invaded readily by P. gingivalis. Further, cellular paxillin from DGFs was degraded markedly by the pathogen. Although protein degradation of alpha5beta1 integrin was induced, its mRNA expression was not affected significantly. CONCLUSIONS: P. gingivalis readily invades DGFs and subsequently degrades paxillin, which impairs cellular motility and likely prevents wound healing and the regeneration of periodontal tissues. These characteristics may be involved in the etiology of DS periodontitis.

Inflammatory responses of gingival epithelial cells stimulated with Porphyromonas gingivalis vesicles are inhibited by hop-associated polyphenols.

BACKGROUND: Periodontitis is induced by an imbalance between bacterial virulence and host defense ability. Porphyromonas gingivalis, a predominant periodontal pathogen, triggers a series of host inflammatory responses that aggravate the destruction of periodontium. Thus, anti-inflammatory reagents are considered desirable for effective periodontal therapy. In the present study, we examined the inhibitory effects of hop bract polyphenol (HBP) on cellular inflammatory responses induced by P. gingivalis membrane vesicles. METHODS: Immortalized human gingival epithelial cells were stimulated with P. gingivalis membrane vesicles, and the effects of HBP on mRNA expression of cyclooxygenase (COX)-2, interleukin (IL)-6 and -8, and matrix metalloproteinase (MMP)-1 and -3 were examined using real-time reverse transcription-polymerase chain reaction. RESULTS: HBP inhibited the mRNA expression of COX-2, IL-6 and -8, and MMP-1 and -3 in a dose-dependent manner, whereas epigallocatechin gallate (a control polyphenol) inhibited COX-2 mRNA expression only. Following further fractionation of HBP to identify the effective components, 2-[(2-methylpropanoyl)-phloroglucinol]1-O-beta-D-glucopyranoside (MPPG) was identified as a significant anti-inflammatory element that completely inhibited the inflammatory mRNA induction. Kaempferol 3-O-beta-glucopyranoside (astragalin) also was found to have anti-inflammatory effects. CONCLUSIONS: HBP is suggested to be a potent inhibitor of cellular inflammatory responses induced by P. gingivalis vesicles. Further, MPPG and astragalin, identified here as effective components of HBP, also may be useful for the prevention and/or attenuation of periodontitis.

[Use of gum elastic bougie for tracheal intubation: comparison of different tracheal tubes].

BACKGROUND: Gum elastic bougie (GEB) is one of the most useful devices for patients whose tracheas are difficult to intubate during anesthetic induction. But no previous study has evaluated the effects of the types of the tracheal tube. We hypothesized that wire-reinforced tracheal tubes were superior to standard tracheal tubes in the success rate of tracheal intubation when using GEB. We compared these two different types of tracheal tubes in using GEB. METHODS: Forty patients were subjected and randomly allocated into two groups; patients intubated with standard tracheal tubes (Group , n = 20) and those with wire-reinforced tracheal tubes (Group S, n = 20). Measured variables were intubation time defined as elapsed time from mouth opening to removal of GEB from tracheal tube, heart rate (HR), and systolic blood pressure(SBP). We also compared trial times of intubation and pharyngeal or laryngeal bleeding as a minor side effect. RESULTS: Trachea was successfully intubated in the frist attempt in 37 patients (92.5%), and the rest of the patients were all intubated at second trial. Intubation times of Group P and Group S were 41.5 +/- 13.9s and 41.3 +/- 11.1s, respectively. There were no significant differences in HR and SBP between the groups. CONCLUSIONS: The type of tracheal tube would not affect the success rate and time of intubation when using gum elastic bougie.

Phosphatidylserine and phosphatidylcholine-containing liposomes inhibit amyloid beta and interferon-gamma-induced microglial activation.

There is increasing evidence that microglial activation is one of the major pathogenic factors for Alzheimer's disease (AD) and the inhibition of the inflammatory activation of the microglia thus appears to be neuroprotective and a potentially useful treatment for AD. Phospholipids such as phosphatidylserine (PS) and phosphatidylcholine (PC) have been reported to modulate the immune function of phagocytes. In addition, PS has been reported to be a nootropics that can be used as nonprescription memory or cognitive enhancers. We therefore evaluated the effects of liposomes, which comprise both PS and PC (PS/PC liposomes), on the microglial production of tumor necrosis factor-alpha (TNF-alpha), nitric oxide (NO), and superoxide (*O(2)-) induced by amyloid beta (Abeta) and interferon-gamma (IFN-gamma). Pretreatment of microglia with PS/PC liposomes considerably inhibited the TNF-alpha, NO and *O(2)- production induced by Abeta/IFN-gamma. These results suggest that PS/PC liposomes have both neuroprotective and antioxidative properties through the inhibition of microglial activation, thus supporting the nootropic and antidementia effect of PS.

Maturation of fimbria precursor protein by exogenous gingipains in Porphyromonas gingivalis gingipain-null mutant.

Porphyromonas gingivalis expresses several virulence factors such as fimbriae and proteases, termed gingipains, which are enzymes that process precursor fimbriae proteins. Thus, gingipain-null mutants lack mature fimbriae. Membrane vesicle-depleted supernatants (VDS) containing soluble gingipains were prepared as an exogenous gingipain fraction. Precursor proteins were treated with VDS and a fimbriated gingipain-null mutant was successfully generated. Experiments showed that the wild strain adhered to and invaded epithelial cells at a greater level than the fimbriated gingipain-null mutant, while adhesion/invasion was prevented in the presence of fetal calf serum, which inhibits gingipain activity. The findings of this study suggest that gingipains expose cellular cryptic ligands in a proteolytic manner and promote fimbriae binding to epithelial cells.

Proinflammatory gene expression in mouse ST2 cell line in response to infection by Porphyromonas gingivalis.

Porphyromonas gingivalis is a predominant periodontal pathogen, whose infection causes inflammatory responses in periodontal tissue and alveolar bone resorption. Various virulence factors of this pathogen modulate host innate immune responses. It has been reported that gingipains degrade a wide variety of host cell proteins, and fimbriae are involved in bacterial adhesion to and invasion of host cells. In the present study, we profiled ST2 stromal cell gene expression following infection with the viable P. gingivalis strain ATCC33277 as well as with its gingipain- and fimbriae-deficient mutants, using microarray technology and quantitative real-time polymerase chain reaction. Using a mouse array of about 20,000 genes, we found that infection with the wild strain elicited a significant upregulation (greater than 2-fold) of expression of about 360 genes in ST2 cells, which included the chemokines CCL2, CCL5, and CXCL10, and other proinflammatory proteins such as interleukin-6 (IL-6) and matrix metalloproteinase-13 (MMP-13). Further, infection with the gingipain-deficient mutant elicited a reduced expression of the CXCL10, IL-6 and MMP-13 genes, suggesting that gingipains play an important role in inducing the expression of those genes following P. gingivalis infection. On the other hand, the pattern of global gene expression induced by the fimbriae-deficient mutant was similar to that by the wild strain. These results suggest that P. gingivalis infection induces gene expression of a wide variety of proinflammatory proteins in stromal cells/osteoblasts, and gingipains may be involved in inducing several of the proinflammatory factors.

Inhibitory effects of tumor necrosis factor-alpha on migration of human periodontal ligament cells.

BACKGROUND: Tumor necrosis factor-alpha (TNF-alpha) is associated with chronic gingival inflammation and is suspected to influence periodontal destruction. However, the exact roles of TNF-alpha in wound healing and periodontal tissue regeneration are largely unknown. In the present study, we examined the effects of TNF-alpha on migration and proliferation of human periodontal ligament (PDL) cells. METHODS: PDL cells were cultured in the presence of TNF-alpha to determine its effects on cellular migration and proliferation. The protein expression profiles of alpha5 and beta1 integrin subunits and their related molecules, paxillin and focal adhesion kinases (FAK), were investigated. Gene expression of fibronectin also was assayed. Further, the activation of Rho-family small guanosine triphosphate (GTP)-binding protein (RhoA) was evaluated using a GTP-loading pull-down assay, and focal adhesion formation by PDL cells after transfection with the expression vector of paxillin-fused green fluorescent protein (GFP) also was observed with confocal microscopy. RESULTS: Cellular migration was impaired by TNF-alpha and recovered following the addition of anti-TNF-alpha antibodies. In contrast, PDL cell proliferation was not affected by TNF-alpha. TNF-alpha upregulated the expression of the alpha5 and beta1 integrin subunits, whereas fibronectin was not overexpressed. Phosphorylation of paxillin and FAK by PDL cells was induced, and RhoA activation also was induced. Confocal microscopic analysis revealed that TNF-alpha induced focal adhesion and stress fiber formation in all parts of the cells. CONCLUSION: Our results suggested that TNF-alpha impairs cellular migration by enhancing cellular adhesive ability following significant focal adhesion and stress fiber formation.

Impaired degradation of matrix collagen in human gingival fibroblasts by the antiepileptic drug phenytoin.

BACKGROUND: Gingival overgrowth (GO) is a serious adverse effect associated with the administration of phenytoin (PHT), with PHT-induced GO characterized by a massive accumulation of extracellular matrix components, especially collagen, in gingival connective tissues. However, the etiology of such collagen accumulation is still largely unknown. We examined the effects of PHT on the collagen degradation process leading to collagen accumulation in human gingival fibroblasts (HGF). METHODS: HGFs were cultured with various concentrations of PHT and viable cell numbers and collagen amounts were determined. Gene and protein expressions of matrix metalloproteinases (MMP) and tissue inhibitors of MMPs (TIMP) were quantified with reverse transcription-polymerase chain reaction (RT-PCR) analyses and Western blotting, respectively. Cellular endocytosis of collagen was assayed using flow-cytometric analysis. The effects of PHT on extracellular signal-regulated kinase 1/2 (ERK1/2) and inhibitor kappaB-alpha (IkappaB-alpha) were assayed. RESULTS: The proliferation of HGFs was not affected by PHT, whereas it significantly increased collagen accumulation. Further, the expressions of MMP-1, -2, and -3 were markedly suppressed by PHT, whereas that of TIMP-1 was induced in a dose- and time-dependent manner. PHT also markedly prevented collagen endocytosis by HGFs, which was associated with the suppression of alpha2beta1-integrin expression. In addition, the phosphorylation of ERK1/2 and IkappaB-alpha degradation were suppressed by PHT. CONCLUSIONS: These results suggest that PHT causes an impaired degradation of collagen by suppression of enzymatic degradation with MMPs/TIMP-1 and alpha2beta1-integrin-mediated endocytosis. Those alterations are likely mediated through the cellular signaling pathways of ERK1/2 and nuclear factor kappaB. These synergistic effects may cause collagen accumulation, leading to GO.

[Mouth opening in relation to the craniocervical position during induction of general anesthesia].

BACKGROUND: Decreased mouth opening and limited neck mobility sometimes make direct laryngoscopy or tracheal intubation difficult and compromise the safety in establishing the airway during induction of general anesthesia. Recent report indicated that mouth opening was related to the craniocervical position in awake subjects. The query about whether the neck position modulate the mouth opening during anesthetic induction under paralyzed condition is not clarified. We hypothesized that the neck extension and the flexion induce changes in inter-incisor distance (IID) during anesthetic induction. METHODS: Thirty relatively young patients for general anesthesia were (male; 20, female; 10) subjected. IID was measured with his/her neck positioned flexed, neutral and extended in the sagittal plane, each at preanesthetic awake period, and during anesthetic induction period. The effect of sniffing position on the mouth opening was also studied. RESULTS: At preanesthetic period, IID (mean +/- SD in mm) at neck flexion (37.4 +/- 7.8) was significantly shorter than both at neutral (44.1 +/- 7.5) and at extension (47.4 +/- 7.0). During induction, significant increase in IID was observed as patients' neck position changed from flexed (31.8 +/- 5.4) to neutral (36.6 +/- 5.4), and extended, (41.7 +/- 8.3). Sniffing position did not affect the mouth opening both at preanesthetic and during anesthetic induction period. CONCLUSIONS: Craniocervical extension may play a desirable role in the airway management with mouth opening widely during anesthetic induction under neuromuscular blockade.