Photobiomodulation of Gingival Cells Challenged with Viable Oral Microbes

The oral cavity, a unique ecosystem harboring diverse microorganisms, maintains health through a balanced microflora. Disruption may lead to disease, emphasizing the protective role of gingival epithelial cells (GECs) in preventing harm from pathogenic oral microbes. Shifting GECs' response from proinflammatory to antimicrobial could be a novel strategy for periodontitis. Photobiomodulation therapy (PBMT), a nonpharmacologic host modulatory approach, is considered an alternative to drugs. While the host cell response induced by a single type of pathogen-associated molecular patterns (PAMPs) was widely studied, this model does not address the cellular response to intact microbes that exhibit multiple PAMPs that might modulate the response. Inspired by this, we developed an in vitro model that simulates direct interactions between host cells and intact pathogens and evaluated the effect of PBMT on the response of human gingival keratinocytes (HGKs) to challenge viable oral microbes at both the cellular and molecular levels. Our data demonstrated that LED pretreatment on microbially challenged HGKs with specific continuous wavelengths (red: 615 nm; near-infrared: 880 nm) induced the production of various antimicrobial peptides, enhanced cell viability and proliferation, promoted reactive oxygen species scavenging, and down-modulated proinflammatory activity. The data also suggest a potential explanation regarding the superior efficacy of near-infrared light treatment compared with red light in enhancing antimicrobial activity and reducing cellular inflammation of HGKs. Taken together, the findings suggest that PBMT enhances the overall barrier function of gingival epithelium while minimizing inflammation-mediated breakdown of the underlying structures.

Association of Radiotherapy Duration With Clinical Outcomes in Patients With Esophageal Cancer Treated in NRG Oncology Trials: A Secondary Analysis of NRG Oncology Randomized Clinical Trials

Importance

For many types of epithelial malignant neoplasms that are treated with definitive radiotherapy (RT), treatment prolongation and interruptions have an adverse effect on outcomes.

Objective

To analyze the association between RT duration and outcomes in patients with esophageal cancer who were treated with definitive chemoradiotherapy (CRT).

Design, Setting, and Participants

This study was an unplanned, post hoc secondary analysis of 3 prospective, multi-institutional phase 3 randomized clinical trials (Radiation Therapy Oncology Group [RTOG] 8501, RTOG 9405, and RTOG 0436) of the National Cancer Institute-sponsored NRG Oncology (formerly the National Surgical Adjuvant Breast and Bowel Project, RTOG, and Gynecologic Oncology Group). Enrolled patients with nonmetastatic esophageal cancer underwent definitive CRT in the trials between 1986 and 2013, with follow-up occurring through 2014. Data analyses were conducted between March 2022 to February 2023.

Exposures

Treatment groups in the trials used standard-dose RT (50 Gy) and concurrent chemotherapy.

Main Outcomes and Measures

The outcomes were local-regional failure (LRF), distant failure, disease-free survival (DFS), and overall survival (OS). Multivariable models were used to examine the associations between these outcomes and both RT duration and interruptions. Radiotherapy duration was analyzed as a dichotomized variable using an X-Tile software to choose a cut point and its median value as a cut point, as well as a continuous variable.

Results

The analysis included 509 patients (median [IQR] age, 64 [57-70] years; 418 males [82%]; and 376 White individuals [74%]). The median (IQR) follow-up was 4.01 (2.93-4.92) years for surviving patients. The median cut point of RT duration was 39 days or less in 271 patients (53%) vs more than 39 days in 238 patients (47%), and the X-Tile software cut point was 45 days or less in 446 patients (88%) vs more than 45 days in 63 patients (12%). Radiotherapy interruptions occurred in 207 patients (41%). Female (vs male) sex and other (vs White) race and ethnicity were associated with longer RT duration and RT interruptions. In the multivariable models, RT duration longer than 45 days was associated with inferior DFS (hazard ratio [HR], 1.34; 95% CI, 1.01-1.77; P = .04). The HR for OS was 1.33, but the results were not statistically significant (95% CI, 0.99-1.77; P = .05). Radiotherapy duration longer than 39 days (vs ≤39 days) was associated with a higher risk of LRF (HR, 1.32; 95% CI, 1.06-1.65; P = .01). As a continuous variable, RT duration (per 1 week increase) was associated with DFS failure (HR, 1.14; 95% CI, 1.01-1.28; P = .03). The HR for LRF 1.13, but the result was not statistically significant (95% CI, 0.99-1.28; P = .07).

Conclusions and Relevance

Results of this study indicated that in patients with esophageal cancer receiving definitive CRT, prolonged RT duration was associated with inferior outcomes; female patients and those with other (vs White) race and ethnicity were more likely to have longer RT duration and experience RT interruptions. Radiotherapy interruptions should be minimized to optimize outcomes.

PCSK9 modulates the Wnt/beta-catenin signaling pathway in myocardial ischemia/reperfusion injury

Background

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a protein that affects cholesterol homeostasis. Recent research has found that PCSK9 has various effects on the heart that are unrelated to LDL cholesterol regulation. The Wnt/β-catenin signaling pathway plays a crucial role during heart development, and it is re-activated in response to cardiac injury. Low-density lipoprotein receptor-related proteins 5 (LRP5) act as co-receptors of Wnt ligands and are indispensable for Wnt/β-catenin signal transduction. However, it is not fully elucidated whether other members of the LDLR-superfamily may be targets of PCSK9.

Purpose

This study aimed to determine if LRP5 is a PCSK9 target, study the association between PCSK9 and Wnt/β-catenin signaling, and elucidate its effect on myocardial infarction in patients with ischemic cardiomyopathy.

Methods

The expression of Lrp5, phospho-β-catenin, total β-catenin was evaluated by western blot analysis, and the effects of overexpressed PCSK9 were tested under normoxia, hypoxia, or hypoxia/re-oxygenation (H/R) in mouse cardiomyocytes (HL-1). The transcriptional activity of β-catenin was assessed using the TOP-Flash/FOP-Flash luciferase reporter assay. In addition, the impact on various downstream targets of the Wnt/β-catenin signaling pathway was assessed using a quantitative real-time polymerase chain reaction. To examine whether PCSK9 regulates injury of cardiomyocytes in vivo, we subjected transgenic mice with cardiac-specific overexpression of PCSK9 (PCSK9 TG) and wild-type (WT) mice to either sham surgery or ischemia/reperfusion (I/R) surgery.

Results

Under hypoxic conditions, the Wnt/β-catenin signaling pathway-related genes were downregulated in HL-1 cells, as evidenced by lower Lrp5 and active phospho-β-catenin expression levels (0.5-fold, n=3, p<0.01). After H/R, the Wnt/β-catenin-related genes were recovered (1.5-fold, p<0.01) in the control group but not in the PCSK9 overexpressed group. In the luciferase reporter assay results, PCSK9 overexpression inhibited the recovery of β-catenin transcriptional activity after H/R, in contrast to the control group. Furthermore, mRNA levels of Axin2, Cyclin D1, which are the Wnt/β-catenin signaling downstream pathway targets, were down-regulated under hypoxia and recovered after H/R but did not recover in PCSK9 overexpressed cells. In the mouse I/R model, the overall protein levels of the Wnt/β-catenin signaling-related genes were down-regulated in PCSK9 TG mice compared to WT mice after I/R injury.

Conclusions

These results indicated that the regulation of PCSK9 is closely associated with the Wnt/β-catenin signaling pathway which may play a crucial role in damaged cardiomyocytes. It suggests that the regulation of PCSK9 could be a therapeutic target in patients with ischemic cardiomyopathy.

Funding Acknowledgement

Type of funding sources: None.

p62/SQSTM1-induced caspase-8 aggresomes are essential for ionizing radiation-mediated apoptosis

The autophagy–lysosome pathway and apoptosis constitute vital determinants of cell fate and engage in a complex interplay in both physiological and pathological conditions. Central to this interplay is the archetypal autophagic cargo adaptor p62/SQSTM1/Sequestosome-1 which mediates both cell survival and endoplasmic reticulum stress-induced apoptosis via aggregation of ubiquitinated caspase-8. Here, we investigated the role of p62-mediated apoptosis in head and neck squamous cell carcinoma (HNSCC), which can be divided into two groups based on human papillomavirus (HPV) infection status. We show that increased autophagic flux and defective apoptosis are associated with radioresistance in HPV(-) HNSCC, whereas HPV(+) HNSCC fail to induce autophagic flux and readily undergo apoptotic cell death upon radiation treatments. The degree of radioresistance and tumor progression of HPV(-) HNSCC respectively correlated with autophagic activity and cytosolic levels of p62. Pharmacological activation of the p62-ZZ domain using small molecule ligands sensitized radioresistant HPV(-) HNSCC cells to ionizing radiation by facilitating p62 self-polymerization and sequestration of cargoes leading to apoptosis. The self-polymerizing activity of p62 was identified as the essential mechanism by which ubiquitinated caspase-8 is sequestered into aggresome-like structures, without which irradiation fails to induce apoptosis in HNSCC. Our results suggest that harnessing p62-dependent sequestration of ubiquitinated caspase-8 provides a novel therapeutic avenue in patients with radioresistant tumors.

Characteristics of an Impaired PDT Response

A concurrent human papilloma virus (HPV) infection potentiates the efficacy of ionizing radiation for treatment of head and neck cancer by promoting apoptosis. Studies in cell culture indicated an opposite effect for photodynamic therapy (PDT) when this leads to mitochondrial and ER photodamage. The explanation for this difference in PDT efficacy remains to be established. While apoptosis was impaired in HPV(-) cells, such cells can be killed via photodamage directed at the ER: this leads to a nonapoptotic death pathway termed paraptosis. No differences in photosensitizer uptake or reactive oxygen species (ROS) production were observed in HPV(+) vs. HPV(-) tumors. We now provide evidence that death pathways initiated by ER/mitochondrial photodamage leading to either paraptosis or apoptosis are impaired in an HPV(+) head and neck cell line. These results illustrate the complex determinants of PDT efficacy, a topic that has yet to be fully explored.

Photodynamic Therapy as a Potent Radiosensitizer in Head and Neck Squamous Cell Carcinoma

Simple Summary

Despite the advances in multimodality treatment strategies, more than 30% of patients with advanced head and neck squamous cell carcinoma (HNSCC) experience recurrence of the disease that is usually derived from the residual tumor. The goal of our study is to understand the molecular basis underlying radiotherapy resistance in advanced HNSCC and to identify a mechanism-based radiosensitizer. We found that the autophagic cell survival pathway is upregulated in therapy-resistant HNSCC. Photodynamic therapy (PDT) directed at the endoplasmic reticulum (ER)/mitochondria induces programmed cell death such as paraptosis and apoptosis in an autophagic adaptor p62-dependent manner, promoting radiotoxicity.

Abstract

Despite recent advances in therapeutic modalities such as radiochemotherapy, the long-term prognosis for patients with advanced head and neck squamous cell carcinoma (HNSCC), especially nonviral HNSCC, remains very poor, while survival of patients with human papillomavirus (HPV)-associated HNSCC is greatly improved after radiotherapy. The goal of this study is to develop a mechanism-based treatment protocol for high-risk patients with HPV-negative HNSCC. To achieve our goal, we have investigated molecular mechanisms underlying differential radiation sensitivity between HPV-positive and -negative HNSCC cells. Here, we found that autophagy is associated with radioresistance in HPV-negative HNSCC, whereas apoptosis is associated with radiation sensitive HPV-positive HNSCC. Interestingly, we found that photodynamic therapy (PDT) directed at the endoplasmic reticulum (ER)/mitochondria initially induces paraptosis followed by apoptosis. This led to a substantial increase in radiation responsiveness in HPV-negative HNSCC, while the same PDT treatment had a minimal effect on HPV-positive cells. Here, we provide evidence that the autophagic adaptor p62 mediates signal relay for the induction of apoptosis, promoting ionizing radiation (XRT)-induced cell death in HPV-negative HNSCC. This work proposes that ER/mitochondria-targeted PDT can serve as a radiosensitizer in intrinsically radioresistant HNSCC that exhibits an increased autophagic flux.

Effects of HPV Status on Responsiveness to Ionizing Radiation vs Photodynamic Therapy in Head and Neck Cancer Cell lines

Efficacy of ionizing radiation (I/R) was compared with phototoxic effects of photodynamic therapy (PDT) in vitro using two cell lines derived from patients with head and neck squamous cell carcinoma (HNSCC). A cell line derived from a donor with a human papilloma virus (HPV) infection was more responsive to I/R but significantly less responsive to PDT than a cell line derived from an HPV-free patient. Cell death after I/R in the HPV(+) cell line was associated with increased DEVDase activity, a hallmark of apoptosis. The HPV(-) line was considerably less responsive to I/R, with DEVDase activity greatly reduced, suggesting an impaired apoptotic program. In contrast, the HPV(-) cells were readily killed by PDT when the ER was among the targets for photodamage. While DEVDase activity was enhanced, the death pathway appears to involve paraptosis until the degree of photodamage reached the LD99 range. These data suggest that PDT-induced paraptosis can be a death pathway for cells with an impaired apoptotic program.

Radiation therapy and immune-related side effects in patients treated with PD-1 inhibitors

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Background: Checkpoint inhibitors exert their antitumor effects by producing a heightened immune state, and inadvertently give rise to immune-mediated toxicities, including pneumonitis and hypothyroidism. We investigated whether these side effects were more common in patients who were treated with both PD-1 inhibitors and radiation. Methods: Our institution’s pharmacy database was used to collect data on patients who received ≥ 1 dose of PD-1 inhibitors, with or without radiation before August 31, 2016. Adverse effects of hypothyroidism, and pneumonitis were recorded and graded based on CTCAEv4. A logistic regression analysis was performed between radiation and hypothyroidism among patients with Hodgkin’s lymphoma (HL) and head and neck squamous cell carcinoma (HNSCC) and between radiation therapy (RT) and pneumonitis in lung cancer patients. Results: 231 patients received at least one dose of PD-1 inhibitors prior to data cut-off. Median age was 65 (24-92). There were 125 patients (54%) with lung cancer, 18 (8%) with HL and 9 (4%) with HNSCC. 115 patients received radiation. HL and HNSCC patients had higher odds to experience hypothyroidism (adjusted p = 0.023) but this did not seem to be due to RT exposure [HR:0.156, 95% CI 0.008-1.122, p = 0.110]. Lung cancer patients with thoracic radiation had higher odds to experience pneumonitis [HR:2.206, 95% CI 0.451-15.931] although this was not statistically significant (p = 0.358). Conclusions: There was no association between RT and hypothyroidism. Our results suggested a possible increased risk of pneumonitis with thoracic radiation among lung cancer patients treated with PD-1 inhibitors, although statistically insignificant. Larger prospective studies are needed to further delineate this effect.

NRG oncology RTOG 9006: a phase III randomized trial of hyperfractionated radiotherapy (RT) and BCNU versus standard RT and BCNU for malignant glioma patients

From 1990 to 1994, patients with newly diagnosed malignant gliomas were enrolled and randomized between hyperfractionated radiation (HFX) of 72.0 Gy in 60 fractions given twice daily and 60.0 Gy in 30 fractions given once daily. All patients received 80 mg/m² of 1,3 bis(2 chloroethyl)-1 nitrosourea on days 1-3 q8 weeks for 1 year. Patients were stratified by age, KPS, and histology. The primary endpoint was overall survival (OS), with secondary endpoints including progression-free survival (PFS) and toxicity. Out of the 712 patients accrued, 694 (97.5%) were analyzable cases (350 HFX, 344 standard arm). There was no significant difference between the arms on overall acute or late treatment-related toxicity. No statistically significant effect for HFX, as compared to standard therapy, was found on either OS, with a median survival time (MST) of 11.3 versus 13.1 months (p = 0.20) or PFS, with a median PFS time of 5.7 versus 6.9 months (p = 0.18). The treatment effect on OS remained insignificant based on the multivariate analysis (hazard ratio 1.16; p = 0.0682). When OS was analyzed by histology subgroup there was also no significant difference between the two arms for patients with glioblastoma multiforme (MST: 10.3 vs. 11.2 months; p = 0.34), anaplastic astrocytoma (MST: 69.8 vs. 50.0 months; p = 0.91) or anaplastic oligodendroglioma (MST: 92.1 vs. 66.5 months; p = 0.33). Though this trial provided many invaluable secondary analyses, there was no trend or indication of a benefit to HFX radiation to 72.0 Gy in any subset of malignant glioma patients.

HPV-associated differential regulation of tumor metabolism in oropharyngeal head and neck cancer

HPV-positive oropharyngeal cancer patients experience significantly lower locoregional recurrence and higher overall survival in comparison with HPV-negative patients, especially among those who received radiation therapy. The goal of the present study is to investigate the molecular mechanisms underlying the differential radiation sensitivity between HPV-negative and HPV-positive head and neck squamous cell carcinoma (HNSCC). Here, we show that HPV-negative HNSCC cells exhibit increased glucose metabolism as evidenced by increased production of lactate, while HPV-positive HNSCC cells effectively utilize mitochondrial respiration as evidenced by increased oxygen consumption. HPV-negative cells express HIF1α and its downstream mediators of glucose metabolism such as hexokinase II (HKII) and carbonic anhydrase IX (CAIX) at higher levels, while the expression level of cytochrome c oxidase (COX) was noticeably higher in HPV-positive HNSCC. In addition, the expression levels of pyruvate dehydrogenase kinases (PDKs), which inhibit pyruvate dehydrogenase activity, thereby preventing entry of pyruvate into the mitochondrial tricarboxylic acid (TCA) cycle, were much higher in HPV-negative HNSCC compared to those in HPV-positive cells. Importantly, a PDK inhibitor, dichloroacetate, effectively sensitized HPV-negative cells to irradiation. Lastly, we found positive interactions between tonsil location and HPV positivity for COX intensity and COX/HKII index ratio as determined by immunohistochemical analysis. Overall survival of patients with HNSCC at the tonsil was significantly improved with an increased COX expression. Taken together, the present study provides molecular insights into the mechanistic basis for the differential responses to radiotherapy between HPV-driven vs. spontaneous or chemically induced oropharyngeal cancer.

Institutional clinical trial accrual volume and survival of patients with head and neck cancer

PURPOSE

National Comprehensive Cancer Network guidelines recommend patients with head and neck cancer (HNC) receive treatment at centers with expertise, but whether provider experience affects survival is unknown.

PATIENTS AND METHODS

The effect of institutional experience on overall survival (OS) in patients with stage III or IV HNC was investigated within a randomized trial of the Radiation Therapy Oncology Group (RTOG 0129), which compared cisplatin concurrent with standard versus accelerated fractionation radiotherapy. As a surrogate for experience, institutions were classified as historically low- (HLACs) or high-accruing centers (HHACs) based on accrual to 21 RTOG HNC trials (1997 to 2002). The effect of accrual volume on OS was estimated by Cox proportional hazards models.

RESULTS

Median RTOG accrual (1997 to 2002) at HLACs was four versus 65 patients at HHACs. Analysis included 471 patients in RTOG 0129 (2002 to 2005) with known human papillomavirus and smoking status. Patients at HLACs versus HHACs had better performance status (0: 62% v 52%; P = .04) and lower T stage (T4: 26.5% v 35.3%; P = .002) but were otherwise similar. Radiotherapy protocol deviations were higher at HLACs versus HHACs (18% v 6%; P < .001). When compared with HHACs, patients at HLACs had worse OS (5 years: 51.0% v 69.1%; P = .002). Treatment at HLACs was associated with increased death risk of 91% (hazard ratio [HR], 1.91; 95% CI, 1.37 to 2.65) after adjustment for prognostic factors and 72% (HR, 1.72; 95% CI, 1.23 to 2.40) after radiotherapy compliance adjustment.

CONCLUSION

OS is worse for patients with HNC treated at HLACs versus HHACs to cooperative group trials after accounting for radiotherapy protocol deviations. Institutional experience substantially influences survival in locally advanced HNC.

Long-term follow-up of the RTOG 9501/intergroup phase III trial: postoperative concurrent radiation therapy and chemotherapy in high-risk squamous cell carcinoma of the head and neck

PURPOSE

Previous analysis of this Intergroup trial demonstrated that with a median follow-up among surviving patients of 45.9 months, the concurrent postoperative administration of cisplatin and radiation therapy improved local-regional control and disease-free survival of patients who had high-risk resectable head-and-neck carcinomas. With a minimum of 10 years of follow-up potentially now available for all patients, these results are updated here to examine long-term outcomes.

METHODS AND MATERIALS

A total of 410 analyzable patients who had high-risk resected head-and-neck cancers were prospectively randomized to receive either radiation therapy (RT: 60 Gy in 6 weeks) or identical RT plus cisplatin, 100 mg/m(2)i.v. on days 1, 22, and 43 (RT + CT).

RESULTS

At 10 years, the local-regional failure rates were 28.8% vs 22.3% (P=.10), disease-free survival was 19.1% vs 20.1% (P=.25), and overall survival was 27.0% vs 29.1% (P=.31) for patients treated by RT vs RT + CT, respectively. In the unplanned subset analysis limited to patients who had microscopically involved resection margins and/or extracapsular spread of disease, local-regional failure occurred in 33.1% vs 21.0% (P=.02), disease-free survival was 12.3% vs 18.4% (P=.05), and overall survival was 19.6% vs 27.1% (P=.07), respectively.

CONCLUSION

At a median follow-up of 9.4 years for surviving patients, no significant differences in outcome were observed in the analysis of all randomized eligible patients. However, analysis of the subgroup of patients who had either microscopically involved resection margins and/or extracapsular spread of disease showed improved local-regional control and disease-free survival with concurrent administration of chemotherapy. The remaining subgroup of patients who were enrolled only because they had tumor in 2 or more lymph nodes did not benefit from the addition of CT to RT.

In vitro evaluation of migratory capacity of human liver stem cells influenced by soluble factors

Although several studies have addressed the engraftment of stem cells into the liver, the exact mechanisms in vivo remain unclear. In this study, we investigated the effects of soluble factors on cell migration using purified, expanded human liver stem cells (HLSCs) obtained from a pediatric liver resection. Using a in vitro transwell migration assay, we evaluated the migratory capacity of HLSCs under the influence of the cytokines tumor necross factor- [TNF]-α, interleukin [IL]-6, and interferon (IFN)-γ or the growth factors vascular endothelial growth factor [VEGF], basic fibroblast growth factor [bFGF], and hepatocyte growth factor [HGF], which are known to be highly secreted during liver injury. We also evaluated the migratory capacity indirectly influenced by cryopreserved human hepatocytes. The migration across the transwell membrane was promoted by VEGF, bFGF, TNF-α, IFN-γ, or hepatocytes. The cryopreserved human hepatocytes especially induced significant migration. These results suggested the presence of unidentified soluble factors from hepatocytes. This experiment described a reliable system for quantitative migration studies to broaden our understanding of the directional nature of cell migration.

Up-front neck dissection followed by concurrent chemoradiation in patients with regionally advanced head and neck cancer

BACKGROUND

The appropriate management of the neck in patients with regionally advanced head and neck cancer remains controversial. The purpose of this study was to retrospectively analyze our institutional experience with up-front neck dissection followed by definitive chemoradiotherapy.

METHODS

Fifty-five patients with radiographic evidence of large or necrotic lymph nodes underwent up-front neck dissection followed by definitive chemoradiation.

RESULTS

The 5-year overall survival (OS) and progression-free survival (PFS) rates were estimated at 71.3% and 64.7%, respectively. There were 2 failures in the dissected neck, for a control rate of 96.7%. There were 7 locoregional failures and 12 distant failures, for locoregional and distant control rates of 87.3% and 78.2%, respectively.

CONCLUSION

Up-front neck dissection followed by chemoradiotherapy resulted in excellent locoregional control, OS, and PFS. Utilization of this strategy should be considered in carefully selected patients with regionally advanced head and neck cancer. © 2012 Wiley Periodicals, Inc. Head Neck, 2012.

Palifermin reduces severe mucositis in definitive chemoradiotherapy of locally advanced head and neck cancer: a randomized, placebo-controlled study

PURPOSE

Oral mucositis (OM) is a debilitating toxicity of chemoradiotherapy for head and neck cancer (HNC). This randomized, placebo-controlled, double-blind study evaluated the efficacy and safety of palifermin to reduce OM associated with definitive chemoradiotherapy for locally advanced HNC.

PATIENTS AND METHODS

Patients receiving conventionally fractionated radiotherapy (2.0 Gy/d, 5 days/wk to 70 Gy) with cisplatin (100 mg/m(2) on days 1, 22, and 43) received palifermin (180 μg/kg) or placebo before starting chemoradiotherapy and then once weekly for 7 weeks. The primary end point was the incidence of severe, observable, and functional OM (WHO grade 3 to 4).

RESULTS

The palifermin (n = 94) and placebo (n = 94) arms were well balanced. The incidence of severe OM was significantly lower for palifermin than for placebo (54% v 69%; P = .041). In the palifermin arm, median time to severe OM was delayed (47 v 35 days), median duration of severe OM was shortened (5 v 26 days), and the incidence of xerostomia grade ≥ 2 was lower (67% v 80%), favoring palifermin; however, the differences were not significant after multiplicity adjustment. Opioid analgesic use, average mouth and throat soreness scores, and chemoradiotherapy compliance were not significantly different between treatment arms. Adverse events were similar between arms (98%, palifermin; 93%, placebo). The most common study drug-related adverse events were rash, flushing, and dysgeusia. After median follow-up of 25.8 months, overall survival and progression-free survival were similar between treatment arms.

CONCLUSION

Although palifermin reduced severe functional OM, its role in the management of locally advanced HNC during chemoradiotherapy remains to be elucidated.

The effect of hot pressing on the physical properties of glass reinforced hydroxyapatite

Hydroxyapatite (HA), being of physiological importance, can be developed synthetically for implant application. A number of avenues have been explored in order to improve the physical and biological properties of a variety of hydroxyapatite composites. However, the fact remains, hydroxyapatite lacks the mechanical properties needed to sustain high loads. This study investigates the advantages of hot pressing on the physical properties of HA and glass reinforced HA (GR-HA). The results show a significant enhancement in the mechanical properties of GR-HA composites compared to HA e.g. flexural bending strength values were given at 91.75 and 88.87 M Nm(-2) for GR-HA (CP15F) and GR-HA (CP20F) respectively, compared to 78.9 M Nm(-2) for HA. The results for other properties such as elastic modulus, fracture toughness, Vicker's hardness, density and porosity also demonstrate the benefit of adding phosphate based glasses as a sintering aid. This is supported by XRD analysis, highlighting the presence of a secondary phase (beta-TCP) in GR-HA systems and the positive effect it has on the physical properties. It must be brought to attention that densification of hot pressed HA and GR-HA composites is reached at a lower temperature compared to a previous study on the same materials that have undergone pressureless sintering.

Postoperative concurrent radiotherapy and chemotherapy for high-risk squamous-cell carcinoma of the head and neck

BACKGROUND

Despite the use of resection and postoperative radiotherapy, high-risk squamous-cell carcinoma of the head and neck frequently recurs in the original tumor bed. We tested the hypothesis that concurrent postoperative administration of cisplatin and radiotherapy would improve the rate of local and regional control.

METHODS

Between September 9, 1995, and April 28, 2000, 459 patients were enrolled. After undergoing total resection of all visible and palpable disease, 231 patients were randomly assigned to receive radiotherapy alone (60 to 66 Gy in 30 to 33 fractions over a period of 6 to 6.6 weeks) and 228 patients to receive the identical treatment plus concurrent cisplatin (100 mg per square meter of body-surface area intravenously on days 1, 22, and 43).

RESULTS

After a median follow-up of 45.9 months, the rate of local and regional control was significantly higher in the combined-therapy group than in the group given radiotherapy alone (hazard ratio for local or regional recurrence, 0.61; 95 percent confidence interval, 0.41 to 0.91; P=0.01). The estimated two-year rate of local and regional control was 82 percent in the combined-therapy group, as compared with 72 percent in the radiotherapy group. Disease-free survival was significantly longer in the combined-therapy group than in the radiotherapy group (hazard ratio for disease or death, 0.78; 95 percent confidence interval, 0.61 to 0.99; P=0.04), but overall survival was not (hazard ratio for death, 0.84; 95 percent confidence interval, 0.65 to 1.09; P=0.19). The incidence of acute adverse effects of grade 3 or greater was 34 percent in the radiotherapy group and 77 percent in the combined-therapy group (P<0.001). Four patients who received combined therapy died as a direct result of the treatment.

CONCLUSIONS

Among high-risk patients with resected head and neck cancer, concurrent postoperative chemotherapy and radiotherapy significantly improve the rates of local and regional control and disease-free survival. However, the combined treatment is associated with a substantial increase in adverse effects.

Sclerosing mucoepidermoid carcinoma with eosinophilia of the thyroid: a case report and review of the literature

We present the clinical and histopathologic findings of a 38-year-old woman recently diagnosed with sclerosing mucoepidermoid carcinoma with eosinophilia of the thyroid (SMECE). This case is of particular interest because of its extremely aggressive clinical course. After total thyroidectomy, there was extensive bilateral thyroid lobe involvement with extension into perithyroidal soft tissues and the modified radical neck dissection contained 35 of 35 positive lymph nodes. This patient underwent 2 further surgeries; the first was a second right neck and supraclavicular surgery for lymph node metastases in which 8 of 11 were positive, followed a few months later by posterior neck surgery in which multiple lymph nodes were positive. Tumor was also documented by histological review from a right axillary lymph node. Imaging evidence of tumor in the lungs and liver was also present. Establishing the correct diagnosis of SMECE involves an awareness of the cyto- and histomorphologic features of this rare malignancy. As evidence that the biologic behavior of this neoplasm may well be more aggressive than previously considered, we briefly present the clinical and biologic course of this patient's neoplasm and a review of the literature.

Effects of ion beam-assisted deposition of hydroxyapatite on the osseointegration of endosseous implants in rabbit tibiae

The aim of this study was to evaluate the effects of coating implants with hydroxyapatite (HA) by an ion beam-assisted deposition (IBAD) method and to compare them with implants prepared with sand-blasted and machined surfaces. Examination of osteoblast cultures displayed no difference in the secretion of alkaline phosphatase (ALP) between the various surfaces, but the IBAD-HA specimen showed low ALP secretion (P < .05). Removal torque tests showed that implants coated with HA by the IBAD method had values similar to the implants with a sandblasted surface, but values for the machined-surface implants differed. Implants placed in a group of ovariectomized rabbits showed lower mechanical test values than implants placed in sham-operated rabbits (P < .05). Implants coated with HA by the IBAD method demonstrated the highest mean bone-to-metal contact ratio on all threads and on the 3 best consecutive threads, followed by the implants with a sandblasted surface and implants with a machined surface (P < .05). Hydroxyapatite-coated implants showed a slightly higher bone-to-implant contact ratio than sandblasted implants, but no statistically significant difference was seen between the 2 materials. The implants placed in ovariectomized rabbits showed lower amounts of bone-to-metal contact than the implants placed in sham-operated rabbits, but no statistically significant difference was seen between the 2 groups. Evaluation of bone volume on all threads and the 3 best consecutive threads showed no statistically significant difference among the different surface treatment groups, but lower bone volume was seen in the ovariectomized rabbits than in the sham-operated animals (P < .05).

MPP(+) downregulates mitochondrially encoded gene transcripts and their activities in dopaminergic neuronal cells: protective role of Bcl-2

The effects of neurotoxins on levels of mitochondrially encoded gene transcripts in a dopaminergic neuronal cell line, MN9D, were examined following treatment with 200 microM N-methyl-4-phenylpyridinium (MPP(+)) or 6-hydroxydopamine (6-OHDA). As confirmed by a Northern blot analysis, levels of cytochrome c oxidase subunit 3 (COX III) and ATPase subunit 6 (ATPase 6) transcript were decreased in a time-dependent manner following treatment with MPP(+) but not with 6-OHDA. Accordingly, enzymatic activity of cytochrome c oxidase (COX) and the intracellular ATP content were also decreased in MPP(+)-treated cells while these remained unaltered in 6-OHDA-treated cells. In the cell death paradigm induced by MPP(+), overexpression of Bcl-2 in MN9D cells (MN9D/Bcl-2) significantly blocked MPP(+)-induced downregulation of COX III and ATPase 6 transcripts. In MN9D/Bcl-2 cells, MPP(+)-induced downregulation of COX activity and the intracellular level of ATP was also blocked. Treatment with a pan-caspase inhibitor, however, neither prevented MPP(+)-induced downregulation of COX activity nor affected intracellular level of ATP in MN9D cells. Taken together, our present data suggest that Bcl-2 may play a regulatory role in energy metabolism by preventing downregulation of mitochondrially encoded gene(s) at a point distinct from its known anticaspase activity in MPP(+)-induced dopaminergic neuronal death.

Disruption of the myocardial extracellular matrix leads to cardiac dysfunction

MMP activity with disruption of structural collagen has been implicated in the pathophysiology of dilated cardiomyopathy. To examine the role of this enzyme in cardiac function, a transgenic mouse was created that constitutively expressed human collagenase (MMP-1) in the heart. At 6 months of age, these animals demonstrated compensatory myocyte hypertrophy with an increase in the cardiac collagen concentration due to elevated transcription of type III collagen. Chronic myocardial expression of MMP-1 produced loss of cardiac interstitial collagen coincident with a marked deterioration of systolic and diastolic function at 12 months of age. This is the first animal model demonstrating that direct disruption of the extracellular matrix in the heart reproduces the changes observed in the progression of human heart failure.

Neutron radiation enhances cisplatin cytotoxicity independently of apoptosis in human head and neck carcinoma cells

Recent advances in combined modality treatment of locally advanced head and neck cancer have improved local and regional disease control and survival with better functional outcome. However, the local and regional failure rate after radiation therapy is still high for tumors that respond poorly to cisplatin-based neoadjuvant chemotherapy. This clinical observation suggests a common biological mechanism for resistance to cisplatin and photon irradiation. In this report, we investigated the molecular basis underlying cisplatin resistance in head and neck squamous carcinoma (HNSCC) cells and asked if fast neutron radiation enhances cisplatin cytotoxicity in cisplatin-resistant cells. We found that cisplatin sensitivity correlates with caspase induction, a cysteine proteinase family known to initiate the apoptotic cell death pathway, suggesting that apoptosis may be a critical determinant for cisplatin cytotoxicity. Neutron radiation effectively enhanced cisplatin cytotoxicity in HNSCCs including cisplatin-resistant cells, whereas photon radiation had little effect on cisplatin cytotoxicity. Interestingly, neutron-enhanced cisplatin cytotoxicity was associated neither with apoptosis nor with cell cycle regulation, as determined by caspase activity assay, annexin V staining, and flow cytometric analysis. Taken together, the present study provides a molecular insight into cisplatin resistance and may also provide a basis for more effective multimodality protocols involving neutron radiation for patients with locally advanced head and neck cancer.

Ion-beam-assisted deposition (IBAD) of hydroxyapatite coating layer on Ti-based metal substrate

A hydroxyapatite layer was formed on the surface of a Ti-based alloy by ion-beam-assisted deposition. The deposition methodology comprised of an electron beam vaporizing a pure hydroxyapatite target, while an Ar ion beam was focused on the metal substrate to assist deposition. All deposited layers were amorphous, regardless of the current level of the ion beam. The bond strength between the layer and the substrate increased steadily with increasing current, while the dissolution rate in a physiological saline solution decreased remarkably. These improvements were attributed to an increase in the Ca/P ratio of the layer. Without ion beam assistance, the Ca/P ratio was much lower than the stoichiometric HAp (Ca/P = 1.67). With ion-beam assistance, the Ca/P ratio of the layer increased presumably due to the high sputtering rate of P compared to that of Ca from the layer being coated.

H-ras, but not N-ras, induces an invasive phenotype in human breast epithelial cells: a role for MMP-2 in the H-ras-induced invasive phenotype

Elevated p21ras expression is associated with tumor aggressiveness in breast cancer including the extent of invasion into fat tissues, infiltration into lymphatic vessels and tumor recurrence. In the present study, we have examined the roles of H-ras and N-ras, members of the human ras gene family, in the pathogenesis of breast cancer. We show that H-ras, but not N-ras, induces an invasive phenotype in human breast epithelial cells (MCF10A) as determined by the Matrigel invasion assay, whereas both H-ras and N-ras induce anchorage-independent growth, as shown by soft agar assay. We examined the effects of H-ras and N-ras activation on the expression of MMP-2 and MMP-9, which can degrade type IV collagen, the major structural collagen of the basement membrane. We show that MMP-2 is efficiently induced by H-ras, whereas MMP-9 induction is more prominent in N-ras-activated MCF10A cells. We also show that H-ras-mediated invasiveness is significantly inhibited when the expression of MMP-2 is down-regulated, using an oligodeoxyribonucleotide complementary to the MMP-2 mRNA, or when MMP-2 activity is blocked by its inhibitor TIMP-2 (tissue inhibitors of matrix metalloproteinase-2). Our results show that the H-ras-induced invasive phenotype is associated more closely with the expression of MMP-2 in human breast epithelial cells, rather than the induction of MMP-9 expression, as shown previously for rat embryonic fibroblasts.

Influence of light intensities on dressing behavior in elderly people

With civilized environments in modern society, since the people tend to depend more on artificial illumination than on natural illumination which makes less discrepancy between day and night life, clarifying the relationship between human life and illumination is necessary. In our previous studies, we found that the subjects dressed faster with thicker clothing in the morning than in the evening when the room temperature decreased from 30 degrees C to 15 degrees C over 1 hour. We considered these results in terms of load error between the actual and set-point values in the core temperature. The present study was designed to examine the effect of bright light (3,000 lx)/dim light (50 lx) exposure (09:30 h-14:30 h) on dressing behavior and thermoregulatory responses in the elderly people during the afternoon cold exposure. Five female subjects were instructed to dress to feel comfortable when the room temperature was decreased from 30 degrees C to 15 degrees C (15:00 h-17:00 h). The subjects felt cooler and dressed more quickly with thicker clothing after dim light exposure, it is conceivable that the set-point value of core temperature is reduced under the bright light condition. We discussed these results in terms of the establishment of set-point values in the core temperature at bright light condition. If the set-point of the core temperature is lower in the bright than in the dim light condition in present experiment, the dressing behavior with thinner clothing in the bright light condition is advantageous, since it enables the core temperature to reach its set-point value more easily.

Echocardiographic assessment of cardiac function in conscious and anesthetized mice

Using a high-frequency linear transducer (15L8), we studied 1) the feasibility of performing echocardiography in nonanesthetized mice compared with mice given pentobarbital sodium (Pento) or a mixture of ketamine and xylazine and 2) the feasibility of echocardiographic evaluation of left ventricular (LV) hypertrophy, dilatation, and function in mice with two-kidney, one-clip hypertension or myocardial infarction (MI). Heart rate (HR) in awake mice was 658 +/- 9 beats/min; Pento and ketamine plus xylazine reduced HR to 377 +/- 11 and 293 +/- 19 beats/min, respectively, associated with a significant decrease in shortening fraction (SF), ejection fraction (EF), and cardiac output (CO) and an increase in LV end-diastolic (LVEDD) and end-systolic dimensions (LVESD). Mice with 4 wk of two-kidney, one-clip hypertension had increased LV mass (15.62 +/- 0. 62 vs. 22.17 +/- 1.79 mg) without altered LV dimensions, SF, EF, or CO. Mice studied 4 wk post-MI exhibited obvious LV dilatation and systolic dysfunction, as evidenced by increased LVEDD and LVESD and decreased SF, EF, and CO. Our findings clearly show the adverse impact of anesthesia on basal cardiac function and the difficulty in interpreting data obtained from anesthetized mice. We believe this is the first study to demonstrate the feasibility of using echocardiography to assess cardiovascular function in the nonanesthetized mouse.

Ginsenoside RH-2 induces apoptotic cell death in rat C6 glioma via a reactive oxygen- and caspase-dependent but Bcl-X(L)-independent pathway

We used the rat C6 gliomal cell line to investigate the potential role of ginsenoside Rh2 (G-Rh2) in brain tumor. G-Rh2 induced many apoptotic manifestations in C6 gliomal cells as evidenced by changes in cell morphology, generation of DNA fragmentation, activation of caspase and production of reactive oxygen species (ROS). As a result, cotreatment with antioxidants or a broad-spectrum caspase inhibitor, N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone effectively attenuated G-Rh2-induced cell death. However, specific cleavage of poly(ADP-ribose)polymerase into 85 kDa protein was not detected as demonstrated in many other apoptotic paradigms. Expression levels of Bcl-2 and Bax remained unchanged following G-Rh2 treatment. Furthermore, G-Rh2-induced cell death in C6 gliomal cells overexpressing antiapoptotic protein, Bcl-X(L), was comparable to that in parental cells. Taken together, our data indicate that G-Rh2-induced cell death is mediated by the generated ROS and the activation of caspase pathway in a Bcl-X(L)-independent manner.

Inhibition of chitin synthase II by catechins from stem bark of Taxus cuspidata

Two flavonoids, (+/-)-catechin and (-)-epicatechin, were isolated from the stem bark of Taxus cuspidata by monitoring chitin synthase II inhibitory activity. The compounds inhibit chitin synthase II with an IC50 of 15 and 29 micrograms/ml, respectively and appear to be selective for chitin synthase II. They did not inhibit chitin synthase III.

Platelet-derived growth factor (PDGF)-signaling mediates radiation-induced apoptosis in human prostate cancer cells with loss of p53 function

Platelet-derived growth factor (PDGF) signals a diversity of cellular responses in vitro, including cell proliferation, survival, transformation, and chemotaxis. PDGF functions as a "competence factor" to induce a set of early response genes expressed in G1 including p21WAF1/CIP1, a functional mediator of the tumor suppressor gene p53 in G1/S checkpoint. For PDGF-stimulated cells to progress beyond G1 and transit the cell cycle completely, progression factors in serum such as insulin and IGF-1 are required. We have recently shown a novel role of PDGF in inducing apoptosis in growth-arrested murine fibroblasts. The PDGF-induced apoptosis is rescued by insulin, suggesting that G1/S checkpoint is a critical determinant for PDGF-induced apoptosis. Because recent studies suggest that radiation-induced signal transduction pathways interact with growth factor-mediated signaling pathways, we have investigated whether activation of the PDGF-signaling facilitates the radiation-induced apoptosis in the absence of functional p53. For this study we have used the 125-IL cell line, a mutant p53-containing, highly metastatic, and hormone-unresponsive human prostate carcinoma cell line. PDGF signaling is constitutively activated by transfection with a p28v-sis expression vector, which was previously shown to activate PDGF alpha- and beta- receptors. Although the basal level of p21WAF1/CIP1 expression and radiation-induced apoptosis were not detectable in control 125-IL cells as would be predicted in mutant p53-containing cells, activation of PDGF-signaling induced expression of p21WAF1/CIP1 and radiation-induced apoptosis. Our study suggests that the level of "competence" growth factors including PDGF may be one of the critical determinants for radiation-induced apoptosis, especially in cells with loss of p53 function at the site of radiotherapy in vivo.

Influence of different light intensities during the daytime on evening dressing behavior in the cold

The primary purpose of this study was to determine the effect of bright light exposure during the daytime on dressing behavior in the cold. Seven female volunteers were exposed to bright light of 4,000 lx ("Bright") or dim light of 10 lx ("Dim") from 10 h to 18 h, complete darkness during the sleep period (22:30 h-06:00 h), and 10 lx for the rest of the time. The subjects were instructed to dress to remain comfortable when the ambient temperature was decreased from 30 degrees to 15 degrees C (20:30 h-22:30 h). Most subjects dressed more quickly and with thicker clothing in the Dim condition and felt cooler during the last 30 min of the temperature fall. The rectal temperature showed clear circadian rhythm both under Bright and Dim conditions, but it was significantly lower during sleep in the Bright condition. It is suggested that the set-point of core temperature is reduced at night during the Bright condition.

Effects of the menstrual cycle on dressing behavior in the cold

The purpose of the present study was to determine the effect of the menstrual cycle on dressing behavior in cold exposure. Rectal and skin temperatures, temperature sensation and metabolic rate were measured in seven women during the luteal (L) and the follicular (F) phases of the menstrual cycle, as was their dressing behavior in these two phases. The subjects were instructed to dress so as to feel comfortable when the ambient temperature was decreased from 30 degrees C to 15 degrees C (07:00-09:00). Most subjects dressed more quickly and with thicker clothing in the L phase. They felt cooler in the L phase during the last 30 min of the temperature fall. Rectal and skin temperatures showed significant differences between L and F phases and metabolic rate was significantly higher in the L phase. The results can be interpreted in terms of the establishment of a higher set-point in core temperature during the L phase.

Effects of endoscopic variceal ligation in lower esophageal motor function: a prospective study

OBJECTIVES

Endoscopic variceal ligation (EVL), a recently developed method for controlling active variceal bleeding and eradicating esophageal varices, has similar efficacy to endoscopic injection sclerotherapy (EIS) and is known to have a minimal risk of complications and fewer complications in the lower esophagus. However, since the site of EVL is chiefly done in the lower esophagus, we prospectively evaluated to investigate the effect of EVL on the lower esophageal motor function.

METHODS

We evaluated the severity of esophageal varix with the endoscopy and the lower esophageal manometry in 27 patients who had no history of interventional therapy, for varices before EVL, 3 weeks and 6 months after the last EVL session.

RESULTS

The EVL caused considerable diminution in the size of esophageal varix by a mean 8.2 (range 3-21) ligations in mean 1.7 (range 1-3) sessions. In most of the cases, the varices reappeared and enlarged when the procedure of EVL was stopped. There were two different types of changes (intermediate and late) in the lower esophageal motility. The intermediate post-EVL effects were the increase of peristaltic contraction amplitude and duration in the lower esophageal body after EVL. The late post-EVL effects were the prolongation of lower esophageal sphinctor (LES) relaxation duration and speedier peristaltic velocity in the lower esophageal body.

CONCLUSIONS

We conclude from these findings that the intermediate post-EVL effect may be transient and the increase of peristaltic wave was due to diminution of esophageal varix.

Effects of time of day on dressing behavior under the influence of ambient temperature fall from 30 degrees C to 15 degrees C

The present paper is aimed at determining whether the dressing behavior for temperature regulation in cold is under the influences of circadian control. The half-naked subjects were instructed to dress in the garments they felt comfortable when the room temperature began to decrease from 30 degrees C to 15 degrees C in 1 h. To determine the effects of brain temperature fall on the dressing behavior, we used face cooling with cool air for 30 min before the room temperature began to decrease. We also studied the effects of wearing a hat on dressing behavior. Rectal temperature, tympanic temperature, skin temperature at seven sites, and thermal sensation were recorded. Major findings are summarized as follows: 1) the subjects dressed faster with thicker clothing in the morning than in the evening; 2) the subjects with face cooling dressed faster with thicker clothing than the subjects without face cooling; 3) the subjects without a hat dressed more rapidly with thicker, heavier clothing. These results were discussed in terms of load error between actual and set-point values in the core temperature.