Wound healing after therapy of oral potentially malignant disorders with a 445-nm semiconductor laser: a randomized clinical trial.

OBJECTIVES: Oral potentially malignant disorders (OPMDs) are the most clinically relevant precursor lesions of the oral squamous cell carcinoma (OSCC). OSCC is one of the 15 most common cancers worldwide. OSCC is with its high rate of mortality an important cause of death worldwide. The diagnosis and therapy of clinically relevant precursor lesions of the OSCC is one of the main parts of prevention of this malignant disease. Targeted therapy is one of the main challenges concerning an oncologically safe tissue removal without overwhelming functional and aesthetic impairment. MATERIALS AND METHODS: In this randomized controlled trial, a newly introduced intraoral 445-nm semiconductor laser (2W; cw-mode; SIROLaser Blue, Dentsply Sirona, Bensheim, Germany) was used in the therapy of OPMDs. Duration and course of wound healing, pain, and scar tissue formation were compared to classical cold blade removal with primary suture by measuring remaining wound area, tissue colorimetry, and visual analogue scale. The study includes 40 patients randomized using a random spreadsheet sequence in two groups (n1 = 20; n2 = 20). RESULTS: This comparative analysis revealed a significantly reduced remaining wound area after 1, 2, and 4 weeks in the laser group compared to the cold blade group (p < 0.05). In the laser group, a significantly reduced postoperative pain after 1 week was measured (p < 0.05). CONCLUSION: Laser coagulation of OPMDs with the investigated 445-nm semiconductor laser is a safe, gentle, and predictable surgical procedure with beneficial wound healing and reduced postoperative discomfort. CLINICAL RELEVANCE: Compared to the more invasive and bloody cold blade removal with scalpel, the 445-nm semiconductor laser could be a new functional less traumatic tool in the therapy of OPMDs. The method should be further investigated with regard to the identification of further possible indications. TRAIL REGISTRATION: German Clinical Trials Register No: DRKS00032626.

Targeted sensitization of tumor cells for radiation through monocarboxylate transporters 1 and 4 inhibition in vitro.

OBJECTIVES: Monocarboxylate transporters (MCT) 1, 2 and 4 play an important role in tumor metabolism. The amount of lactate transported by MCT's highly correlates with overall survival. Furthermore, glycolysis and hypoxia are possible causes for radiation resistance. MATERIALS AND METHODS: An oral squamous cell carcinoma cell line (CAL27, ATCC) was analyzed in an in vitro cell assay. After incubation with two different inhibitors for MCT1 (AR-C122982/SR-13800 and AR-C155858/SR-13801, Tocris) or for MCT4 (simvastatin, Sigma-Aldrich and 2-cyano-3-(4-hydroxyphenyl)-2-propenoic acid (CHC), Tocris), cells were irradiated with six gray with a Gammacell 2000 (Nuklear Data). For analysis, cell counting assay, wound healing assay, MTT assay and clonogenic assay were applied. RESULTS: Cell counting assay showed significant lower results for simvastatin, CHC and for the highest concentrations of AR-C122982 and AR-C155858 (p < 0.03). Additionally, cell counts decreased significantly with irradiation after 72 hours (p < 0.05) only for AR-C122982, CHC and simvastatin. The clonogenic assay confirmed these results with substantially reduced growth when incubated with CHC, simvastatin and AR-C155858 (p < 0.002). Furthermore, MCT1 and 4 inhibition led to highly reduced migration (p < 0.05). There again, comparing the wound healing assay of irradiated to non-irradiated tests showed contrary results (controls: p < 0.001; AR-C155858: p > 0.05; AR-C122982: p > 0.32; CHC: p > 0.1; simvastatin p > 0.1). The MTT assay presented significant effects with MCT1 and 4 inhibition (simvastatin/AR-C122982/CHC: p < 0.007). Irradiated cells showed significantly lower expression after only 48 h compared to non-irradiated cells (simvastatin/AR-C122982/CHC: p < 0.02). CONCLUSIONS: Inhibition of MCT, especially MCT4 may represent a possible tool to overcome radiation resistance in tumor cell lines. CLINICAL RELEVANCE: MCT Inhibitors may be used as a possible therapeutic approach to sensitize OSCC to radiation.

Efficiency of soft tissue incision with a novel 445-nm semiconductor laser.

Using a 445-nm semiconductor laser for tissue incision, an effective cut is expected due to the special absorption properties of blue laser light in soft tissues. The aim of the present study was the histological evaluation of tissue samples after incision with a 445-nm diode laser. Forty soft tissue specimens were obtained from pork oral mucosa and mounted on a motorized linear translation stage. The handpiece of a high-frequency surgery device, a 970-nm semiconductor laser, and a 445-nm semiconductor laser were connected to the slide, allowing a constant linear movement (2 mm/s) and the same distance of the working tip to the soft tissue's surface. Four incisions were made each: (I) 970-nm laser with conditioned fiber tip, contact mode at 3-W cw; (II-III): 445-nm laser with non-conditioned fiber tip, contact mode at 2-W cw, and non-contact mode (1 mm) at 2 W; and (IV): high-frequency surgery device with straight working tip, 90° angulation, contact mode at 50 W. Histological analysis was performed after H&E staining of the embedded specimens at 35-fold magnification. The comparison of the incision depths showed a significant difference depending on the laser wavelength and the selected laser parameters. The highest incision depth was achieved with the 445-nm laser contact mode (median depth 0.61 mm, min 0.26, max 1.17, interquartile range 0.58) (p < 0.05) with the lowest amount of soft tissue denaturation (p < 0.05). The lowest incision depth was measured for the high-frequency surgical device (median depth 0.36 mm, min 0.12, max 1.12, interquartile range 0.23) (p < 0.05). Using a 445-nm semiconductor laser, a higher cutting efficiency can be expected when compared with a 970-nm diode laser and high-frequency surgery. Even the 445-nm laser application in non-contact mode shows clinically acceptable incision depths without signs of extensive soft tissue denaturation.

The enhancing effect of a laser photochemotherapy with cisplatin or zolendronic acid in primary human osteoblasts and osteosarcoma cells in vitro.

BACKGROUND: Photodynamic therapies (PDT) have become increasingly popular in the adjuvant treatment of different tumour entities. Chemotherapeutic agents, such as cisplatin may be used in combination with low-level laser therapy (LLLT) as laser photochemotherapy. The aim of this study was to investigate the effect of LLLT on cell bioviability of normal and malignant bone cells under chemotherapeutic conditions with either cisplatin or zolendronic acid in vitro. METHODS: Primary human osteoblasts (HOB) and an osteosarcoma cell line (Saos-2) were treated with different concentrations of zolendronic acid or cisplatin and irradiated twice with a diode laser (wavelength 670 nm, 120 s, energy outputs of 100mW/cm2 , continuous wave mode). Cell viability was tested by XTT-assay and via histomorphological analysis. RESULTS: LLLT alone increased bioviability for both cell lines. LLLT lowered HOB viability at the three highest concentrations of cisplatin and zolendronic acid. For Saos-2, LLLT reduced cell viability at every concentration of cisplatin. In cases of incubation with zolendronic acid, similar to osteoblasts, LLLT lowered cell viability at the highest concentration only. CONCLUSIONS: Based on the conditions of this study, laser photochemotherapy may be able to raise the cytotoxicity of cisplatin and zolendronic acid in benign and malignant bone cells. This could be of interest in the development of new therapeutic treatment modalities against neoplastic bone diseases like osteosarcoma.

The expression of melanoma-associated antigen A (MAGE-A) in oral squamous cell carcinoma: an evaluation of the significance for tumor prognosis.

OBJECTIVES: Melanoma-associated antigens A had been detected repeatedly in oral squamous cell carcinoma, but not in healthy mucosa. Additionally, patients with MAGE-A expressing cancers are regarded to have a worse survival prognosis, so that MAGE-A are supposed to be part of carcinogenesis. Which role these antigens fulfill within OSCC is still, up today, largely unknown. This study examines the hypothesis that MAGE-A is being produced in OSCC but not in mucosa tissue and if MAGE-A has any correlation to clinical patient's parameters like tumor size, lymph node metastasis, distant metastasis, overall survival, and recurrence. MATERIALS AND METHODS: For this purpose, 50 tumor samples and 39 mucosa samples were analyzed by means of PCR and immunohistochemical staining with the antibody 6C1. RESULTS: Forty of 41 stained tumor samples showed a positive antibody reaction with a maximum staining rate of 53%. Sixteen mucosa samples showed a mild positive reaction. The PCR revealed a linear expression pattern of MAGE-A in which the genes are proportionally expressed in OSCC. We did not find any relationship between MAGE-A and tumor size, overall survival, or recurrence. There was also no connection between MAGE-A and tumor parameters Hif-1 and LDH. Their expression was detected tendentially in tumors with higher staging, advanced lymph node metastasis, and rising age of the patients. The genes MAGE-A3+6 and MAGE-A4 had a statistically significant correlation with lymph node metastasis (p = 0.007 and p = 0.004). Patients got distant metastasis and influence of MAGE-A on metastatic behavior could not be verified. The genes MAGE-A3 and -A4 are consequently qualified as tumor markers in the field of diagnosis and follow-up of OSCC. CONCLUSIONS AND CLINICAL RELEVANCE: Two genes have great potential as target proteins in immunotherapy. The genes MAGE-A3+6 and MAGE-A4 had a statistically significant correlation with lymph node metastasis.

Endogenous and Exogenous Melatonin Exposure Attenuates Hepatic MT1 Melatonin Receptor Protein Expression in Rat.

Melatonin receptors are highly relevant for the hepatoprotective effects of the pineal hormone melatonin after experimental hemorrhagic shock in rats. In this study, we sought to determine the spatial expression pattern and a putative regulation of two melatonin receptors, membrane bound type 1 and 2 (MT1 and MT2), in the liver of rats. In a male rat model (Sprague Dawley) of hemorrhage and resuscitation, we investigated the gene expression and protein of MT1 and MT2 in rat liver by utilizing real-time quantitative polymerase chain reaction, a western blot analysis, and immunohistochemistry. Plasma melatonin content was measured by an enzyme-linked immunosorbent assay. Male rats underwent hemorrhage and were resuscitated with shed blood and a Ringer's solution (n = 8 per group). After 90 min of hemorrhage, animals were given vehicle, melatonin, or ramelteon (each 1.0 mg/kg intravenously). Sham-operated controls did not undergo hemorrhage but were treated likewise. Plasma melatonin was significantly increased in all groups treated with melatonin and also after hemorrhagic shock. Only MT1, but not the MT2 messenger ribonucleic acid (mRNA) and protein, was detected in the rat liver. The MT1 protein was located in pericentral fields of liver lobules in sham-operated animals. After hemorrhagic shock and treatment with melatonin or ramelteon, the hepatic MT1 protein amount was significantly attenuated in all groups compared to sham controls (50% reduction; p < 0.001). With respect to MT1 mRNA, no significant changes were observed between groups (p = 0.264). Our results indicate that both endogenous melatonin exposure from hemorrhagic shock, as well as exogenous melatonin and ramelteon exposure, may attenuate melatonin receptors in rat hepatocytes, possibly by means of desensitization.

Selective activation of melatonin receptors with ramelteon improves liver function and hepatic perfusion after hemorrhagic shock in rat.

OBJECTIVE: Melatonin may attenuate organ damage via direct antioxidative properties, and was recently demonstrated to reduce cardiac and hepatic injury through receptor-dependent effects. However, the relevance of an isolated activation of melatonin receptors for organ protection, excluding direct antioxidant effects, has not been established yet. This study was designed to investigate whether therapy with melatonin receptor agonist and hypnotic substance ramelteon may improve liver function, hepatic perfusion, and hepatic integrity after hemorrhagic shock in rat. DESIGN: Prospective, randomized, controlled study. SETTING: University research laboratory. SUBJECTS: Male Sprague-Dawley rats (n = 10 per group). INTERVENTIONS: Animals underwent hemorrhagic shock (mean arterial pressure 35 +/- 5 mm Hg for 90 mins) and were resuscitated with shed blood and Ringer's lactate (2 hrs). At the end of shock, animals were treated with ramelteon (1.0 mg/kg intravenously), melatonin receptor antagonist luzindole plus ramelteon (each 1.0 mg/kg intravenously), or vehicle. MEASUREMENTS AND MAIN RESULTS: In vitro, ramelteon displayed no relevant antioxidant capacity in an 2,2'-Azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) assay, compared with melatonin. In vivo, liver function was assessed by plasma disappearance rate of indocyanine green, and intravital microscopy was performed for evaluation of hepatic perfusion index, nicotinamide adenine dinucleotide phosphate autofluorescence, and hepatic integrity. Compared with vehicle controls, ramelteon therapy significantly improved plasma disappearance rate of indocyanine green (7.89 +/- 2.12% vs. 13.67 +/- 2.51%; p = 0.006), hepatic perfusion index (352.04 +/- 111.78 pl/sec/mm vs. 848.81 +/- 181.38 pl/sec/mm; p = 0.002), nicotinamide adenine dinucleotide phosphate autofluorescence and hepatocellular injury. Coadministration of luzindole abolished the protective effect of ramelteon with respect to liver function and nicotinamide adenine dinucleotide phosphate autofluorescence. CONCLUSIONS: Ramelteon therapy improves liver function, hepatic perfusion, and hepatocellular integrity after hemorrhagic shock in rat. This demonstrates that an isolated activation of melatonin receptors may be sufficient for organ protection, independent from direct antioxidant effects. The hypnotic ramelteon could thus play an interesting role in future sedation concepts for critical care patients.

Analgesic prescribing patterns of dental practitioners in Germany.

PURPOSE: To analyze the prescribing patterns of analgesics by dentists in Germany during an investigation period of five years in comparison to analgesic prescriptions by physicians and in relation to international prescribing data. MATERIALS AND METHODS: We analyzed nationwide data of all prescriptions of analgesics and antiphlogistics (except strong opioids) on the basis of the annual reports of the German statutory health insurances from 2012 to 2016. The types of analgesics, the number of prescriptions and the prescribed 'defined daily doses' (DDD) itemized by dentists and physicians were analyzed. The results were compared with each other and assigned to international dental prescribing data. RESULTS: During the investigation period the number of dental prescriptions of analgesics decreased by 3.4%, on the part of the physicians the increase amounted to 10.4%. Ibuprofen is the first line analgesic in Germany, its share in the dental analgesic prescription volume increased from 61.9% in 2012 to 88.1% in 2016. In the international comparison it could be demonstrated that nonsteroidal anti-inflammatory drugs (NSAIDs) play the most important role in nearly all countries. CONCLUSIONS: Continual training activities and international monitoring of dental analgesic prescription patterns are necessary to develop guidelines for the rational and appropriate use of analgesics in dentistry.

Modulation of Tumor Cell Metabolism by Laser Photochemotherapy with Cisplatin or Zoledronic Acid In Vitro.

BACKGROUND/AIM: Laser photochemotherapy is a new approach in cancer treatment using low-level laser therapy (LLLT) to enhance the effect of chemotherapy. MATERIALS AND METHODS: In order to evaluate the effect of LLLT on tumor cells, HeLa cells were treated with cisplatin or zoledronic acid (ZA) followed by LLLT. Cell viability was evaluated with 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide assay. Oxidative phosphorylation and glycolysis were measured using extracellular flux analysis. Immunocytochemistry of heat-shock protein 70 (HSP70) and western blot analysis were performed. RESULTS: LLLT alone increased viability and was associated with lower oxidative phosphorylation but higher glycolysis rates. Cisplatin and ZA alone lowered cell viability, glycolysis and oxidative phosphorylation. This effect was significantly enhanced in conjunction with LLLT and was accompanied by reduced oxidative phosphorylation and collapse of glycolysis. CONCLUSION: Our observations indicate that LLLT may raise the cytotoxicity of cisplatin and ZA by modulating cellular metabolism, pointing to a possible application in cancer treatment.

Trends in antibiotic prescribing by dental practitioners in Germany.

PURPOSE: To analyze the structure of antibiotic prescriptions by dentists in Germany during a time-period of four years in relation to medical antibiotic prescriptions. MATERIALS AND METHODS: We collected nationwide data from all statutory health insurances on dental prescriptions of systemic antibiotics from 2012 to 2015. The annual reports of the "Research Institute for Local Health Care Systems" (WIdO, Berlin) provided the basis for this longitudinal data base analysis. The types of antibiotics, the number of prescriptions and the prescribed 'defined daily doses' (DDD) were analyzed. The results were compared to antibiotic prescriptions of German physicians. RESULTS: An average of 8.8% per year of all antibiotic prescriptions is issued by dentists. The mostly prescribed antibiotic is amoxicillin. The share of amoxicillin on all dental prescriptions increased from 35.6% in 2012 to 45.8% in 2015 (p < 0.01). About three-quarters of all dentally prescribed DDD can be attributed to amoxicillin and clindamycin. On the part of the physicians the proportion of clindamycin is 18 fold lower than in the dental field. CONCLUSIONS: Dental and medical antibiotic prescriptions in Germany show statistically significant differences regarding the shares of the prescribed antibiotics. In an international comparison the high proportion of Clindamycin in Germany is noticeable.

Impact of Soft Tissue Pathophysiology in the Development and Maintenance of Bisphosphonate-Related Osteonecrosis of the Jaw (BRONJ).

Since the first description of bisphosphonate-related osteonecrosis of the jaw (BRONJ), numerous research groups have focused on possible pathological mechanisms including the suppression of the bone turnover of the jaw, antiangiogenic effects and soft tissue toxicity. In our review we focused on summarizing the role of the soft tissues in the development and progression of BRONJ. The biological behavior of fibroblasts can be significantly influenced by bisphosphonates (BP) such as a concentration dependent reduction of cell viability. High concentrations of BP can induce apoptosis and necrosis of the cells. Comparable effects could be detected for keratinocytes. Compared to non-nitrogen containing bisphosphonates, nitrogen-containing BP have worse effects on cell biology by blocking the mevalonate pathway. Further, the cell architecture and expression levels of several genes and proteins are significantly disturbed by BP. These inhibitory effects of BP are in accordance with BP-related reduced angiogenesis and neovascularization and could underline the hypothesis that inhibition of fibroblasts and keratinocytes results in delayed wound healing and can induce and trigger BRONJ.

Laser-enhanced cytotoxicity of zoledronic acid and cisplatin on primary human fibroblasts and head and neck squamous cell carcinoma cell line UM-SCC-3.

INTRODUCTION: Low-level laser therapy (LLLT) is used in parodontitis treatment in combination with an antimicrobial photosensitizer. The purpose of this study was to investigate the combination of LLLT with cisplatin and zoledronic acid as potential photosensitizer in-vitro. MATERIALS AND METHODS: Primary human fibroblasts (PHF) and head and neck squamous cell carcinoma cells (HNSCC, exactly UM-SCC-3) were treated with different concentrations of zoledronatic acid and cisplatin and irradiated twice with a diode laser (wavelength 670 nm, 2 min). Cell viability was tested by XTT assay and histomorphological analysis with HE staining. RESULTS: LLLT increased bioviability for both cell lines (p < 0.001). LLLT lowered PHF viability at the highest concentrations of cisplatin (p = 0.027 and p = 0.005) and zoledronic acid (p < 0.001). For HNSCCs, LLLT reduced cell viability at every concentration of cisplatin (all p < 0.05). In cases of incubation with zoledronic acid, similar to fibroblasts, laser therapy lowered cell viability at the highest concentration only (p < 0.001). CONCLUSIONS: Within the limits of this study, it can be concluded that LLLT enhances the effect of cisplatin and zoledronic acid in the discussed cells in order to develop new therapeutic options for cysts in the cranio-maxillofacial region and other appropriate indications.

Dobutamine pretreatment improves survival, liver function, and hepatic microcirculation after polymicrobial sepsis in rat.

Dobutamine is recommended for the treatment of sepsis-related circulatory failure in international guidelines. Furthermore, dobutamine has been demonstrated to improve liver function and hepatic perfusion after experimental hemorrhagic shock. Yet, it is unknown whether dobutamine may also induce hepatoprotective effects in sepsis. This study was designed to investigate the effect of dobutamine on survival, hepatic function, and microcirculation after polymicrobial sepsis in rat. Under general anesthesia, male Sprague-Dawley rats (n = 25/group) underwent pretreatment with dobutamine (10 µg/kg per minute) in the presence or absence of ß1-receptor antagonist esmolol (500 µg/kg per minute), esmolol alone, or vehicle for 6 h, before induction of sepsis (cecal ligation and incision [CLI]). Sham-operated animals were treated likewise but underwent no CLI. Five hours after CLI, either liver function was assessed by plasma disappearance rate of indocyanine green (n = 5/group), or intravital microscopy was performed (n = 5/group) for evaluation of hepatic perfusion index and hepatic integrity (as propidium iodide-stained cells per field). Alternatively, survival time after induction of CLI was monitored under general anesthesia (n = 15/group). Compared with controls, dobutamine pretreatment significantly improved plasma disappearance rate of indocyanine green (13.8% ± 4.1% vs. 20.6% ± 4.6%; P = 0.029), hepatic perfusion index (275.0 ± 126.1 vs. 703.5 ± 177.4 pL/s per mm; P < 0.001), hepatocellular injury (22.2 ± 6.7 vs. 6.4 ± 3.1 cells per field; P < 0.001), and survival time (326 ± 20 vs. 603 ± 41 min; P < 0.001). Coadministration of esmolol abolished the protective effect of dobutamine completely. Our results indicate that pretreatment with dobutamine may improve survival, liver function, and hepatic microcirculation after polymicrobial sepsis in rat via ß1-adrenoceptor activation. Dobutamine could therefore play a relevant role for hepatoprotection under septic conditions.