Non-muscle myosin II as a predictive factor in head and neck squamous cell carcinoma.

BACKGROUND: The present study attempted to provide information regarding non-muscle myosin II (MII) isoforms immunoreactivity in patients with head and neck squamous cell carcinoma (HNSCC) and analysis of the patients' clinical status after 5 years of monitoring. MATERIAL AND METHODS: A semiquantitative analysis of the immunoreactivity of the MII isoforms was performed in 54 surgical specimens and its correlation with clinical and pathological variables and prognosis was verified. Data were analyzed using chi-square, Mann-Whitney and Kruskal-Wallis tests. To evaluate the survival over the total monitoring time and any connection with the proteins studied, the Kaplan-Meier analysis was used. P values ≤0.05 were considered statistically significant. RESULTS: In the advanced stages of pathological tumor-node-metastasis, the expression of MIIB in adjacent non-neoplastic epithelial tissues tended to increase (p = 0.057). In tumoral zones there was an association of high expression among the three isoforms (MIIA/MIIB p=0,001, MIIB/MIIC p=0,006 and MIIA/MIIC p=0,012). Negative clinical evolution in patients was directly correlated to increased MIIC expression in the tumoral zone of invasion in HNSCC (p = 0.017). Based on clinical evolution after the monitoring period, patients with tumors expressing MIIC had poorer prognoses (p = 0.048). CONCLUSIONS: The present study suggests that MIIB expression in non-neoplastic adjacent epithelial tissues may indicate a potential for regional metastasis and that MIIC expression in the tumoral zone of invasion is predictive of negative evolution of the disease.

Low-level laser therapy improves peri-implant bone formation: resonance frequency, electron microscopy, and stereology findings in a rabbit model.

Previous studies have reported positive effects of low-level laser therapy (LLLT) on bone healing. This study evaluated the effects of LLLT on peri-implant healing in vivo. Thirty-two rabbits had their mandibular left incisors removed, followed by immediate insertion of a dental implant into the fresh socket. Animals were assigned randomly to four groups: control (non-irradiated) or LLLT at three different doses per session: 5J/cm(2), 10J/cm(2), and 20J/cm(2). A GaAlAs laser (830nm, 50mW) was applied every 48h for 13 days, starting immediately after surgery. The implant stability quotient (ISQ) was measured using resonance frequency analysis upon implant insertion and immediately after death, 30 days after the last application. Tissues were prepared for scanning electron microscopy (SEM) and stereology. Variables measured were bone-implant contact (BIC) and bone neoformation within implant threads at three different sites. The results showed better ISQ for the 20J/cm(2) group (P=0.003). BIC values were significantly higher (P<0.05) in the 20J/cm(2) group, on both SEM and stereology. Bone area values were better in the 10J/cm(2) (P=0.036) and 20J/cm(2) (P=0.016) groups compared to the control group. Under these conditions, LLLT enhanced peri-implant bone repair, improving stability, BIC, and bone neoformation. The findings support and suggest parameters for the design of clinical trials using LLLT after implant placement.

Evaluation of anti-nociceptive and anti-inflammatory activity of low-level laser therapy on temporomandibular joint inflammation in rodents.

The aim of this study was to investigate the analgesic and anti-inflammatory activity of low-level laser therapy (LLLT) on the nociceptive behavioral as well as histomorphological aspects induced by injection of formalin and carrageenan into the rat temporomandibular joint. The 2.5% formalin injection (FRG group) induced behavioral responses characterized by rubbing the orofacial region and flinching the head quickly, which were quantified for 45 min. The pretreatment with systemic administration of diclofenac sodium-DFN group (10 mg/kg i.p.) as well as the irradiation with LLLT infrared (LST group, 780 nm, 70 mW, 30 s, 2.1 J, 52.5 J/cm(2), GaAlAs) significantly reduced the formalin-induced nociceptive responses. The 1% carrageenan injection (CRG group) induced inflammatory responses over the time-course of the study (24 h, and 3 and 7 days) characterized by the presence of intense inflammatory infiltrate rich in neutrophils, scanty areas of liquefactive necrosis and intense interstitial edema, extensive hemorrhagic areas, and enlargement of the joint space on the region. The DFN and LST groups showed an intensity of inflammatory response that was significantly lower than in CRG group over the time-course of the study, especially in the LST group, which showed exuberant granulation tissue with intense vascularization, and deposition of newly formed collagen fibers (3 and 7 days). It was concluded that the LLLT presented an anti-nociceptive and anti-inflammatory response on the inflammation induced in the temporomandibular joint of rodents.

Assessment of the systemic effects of low-level laser therapy (LLLT) on thyroid hormone function in a rabbit model.

The aim of this study was to assess the effects of low-level laser therapy (LLLT) applied to a dental extraction socket on thyroid gland function in a rabbit model, based on serum triiodothyronine and thyroxine levels. Sixteen male New Zealand rabbits were randomly distributed into two groups: a control group (non-irradiated animals) and an experimental group (irradiated animals: one irradiation point in the extraction socket of the lower incisor). Animals in the experimental group were irradiated with an aluminium gallium arsenide diode laser (AlGaAs; wavelength 830 nm, 40 mW, CW laser), for 13 days, every 48 h, at a dose of 6 J/cm(2) per session, resulting in a total dose of 42 J/cm(2). Serum triiodothyronine and thyroxine levels were measured in both groups before extraction and on the last day of observation (day 15). There were no statistically significant differences between the groups in pre- and post-irradiation triiodothyronine and thyroxine values. With the irradiation protocol used in this study, LLLT did not affect thyroid function in rabbits as assessed by circulating serum triiodothyronine and thyroxine levels.

Evaluation of nitric oxide (NO) and nitric oxide synthases (NOS) in the amniotic fluid in an experimental gastroschisis rat model.

UNLABELLED: Intestinal damage due to gastroschisis (G), an anomaly found with increasing incidence by pediatric surgeons, is intimately associated with endogenous nitric oxide (NO) production and NO synthase (NOS) expression. AIM: Aim of the study was to evaluate NO production and NOS isoforms in the intestine and amniotic fluid (AF) using a rat model of gastroschisis. METHODS: A gastroschisis rat model was surgically created at 18.5 days of gestation (term=22 days). 3 groups of 12 fetuses each were studied: control (C), sham (S) and (G). Morphometric data of body weight (BW), intestinal weight (IW) and the IW/BW ratio were evaluated and compared. Indirect quantification of NO (nitrite and nitrate - NOx) was analyzed by chemiluminescence, and the expression of the 3 isoforms was analyzed by Western blotting. RESULTS: Group G showed an increase in IW and IW/BW compared with groups C and S. IW: G=0.27 ± 0.06, C=0.20 ± 0.02, S=0.20 ± 0.02 (p<0.01); IW/BW: G=4.11 ± 0.57, C=5.21 ± 1.04, S=5.18 ± 1.23 (p<0.05). NO in the G group was lower in the intestine and higher in AF, as opposed to C and S, where it had increased in the intestine and decreased in AF. Intestinal NOx: G=0.85 ± 0.28, C=1.86 ± 0.82, S=1.80 ± 0.69 (p<0.05); NOx in AF: G=161.87 ± 52.11, C=6.99 ± 5.45, S=48.73 ± 13.183 (p<0.001). CONCLUSION: The intestinal inflammation in gastroschisis promotes the release of nitric oxide to the environment (AF). Perhaps NO in the AF may be an inflammatory marker for G.

Topical S-nitrosoglutathione-releasing hydrogel improves healing of rat ischaemic wounds.

Topical application of the nitric oxide (NO) donor S-nitrosoglutathione (GSNO) is known to exert beneficial effects on wound healing. The aim of this study was to evaluate, for the first time, the effect of topical application of GSNO on the healing of ischaemic wounds. Wistar rats were submitted to two parallels incisions on their backs; the skin was separated from the underlying tissue, the incisions were sutured and an excisional wound was made between the parallel incisions to create an ischaemic condition surrounding the wound. The animals were separated into a control group, which received a hydrogel vehicle without GSNO, and a GSNO-treated group, which received a GSNO-containing hydrogel. The animals were treated for 7 days consecutively with one daily application. The GSNO-treated group displayed higher rates of wound contraction and re-epithelization, lower amounts of inflammatory cells, an increase in collagen fibre density and organization and a decrease in the neovascularization compared to control. These results show that topical application of GSNO is effective in the treatment of ischaemic wounds, leading to a significant improvement in the wound healing. Therefore, topical GSNO-containing hydrogels have potential for the therapeutic treatment of ischaemic diabetic and venous ulcers.

Effects of the LactoSorb bioabsorbable plates on the craniofacial development of rabbits: direct morphometric analysis using linear measurements.

The use of plates for the treatment of fractures can affect craniofacial bone development. This study investigated the effect of bioabsorbable plates and titanium microscrews on the growth of the craniofacial skeleton of rabbits (Oryctolagus cuniculus), in the neonatal period. A LactoSorb plate and PROMM titanium microscrews were positioned across the coronal suture in animals in the study group. In the control group, only PROMM titanium microscrews were attached to the cranium. Anteroposterior linear measurements were obtained using 3 different gauging devices: digital precision caliper, EKG caliper and nylon string. Frontal-nasal (FN) distances were statistically different between the left and right side when the digital caliper (P

Antiatherogenic effects of S-nitroso-N-acetylcysteine in hypercholesterolemic LDL receptor knockout mice.

BACKGROUND: The pathophysiology of the NO/NO synthase system and dysfunctional changes in the endothelium in the early phases of the atherogenic process are incompletely understood. In this study, we investigated the effects of the nitrosothiol NO donor S-nitroso-N-acetylcysteine (SNAC) in the early prevention of plaque development in the hypercholesterolemic LDLr-/- mice as well as the changes in endothelium-dependent relaxation and NO synthase expression. METHODS AND RESULTS: LDLr-/- mice were fed a 1.25% cholesterol-enriched diet for 15 days. Plasma cholesterol/triglyceride levels increased and this increase was accompanied by the development of aortic root lesions. Aortic vasorelaxation to acetylcholine was increased, although endothelium-independent relaxation in response to sodium nitroprusside did not change, which suggest stimulated NO release enhanced. This dysfunction was associated with enhanced aortic superoxide production and with increased levels of constitutive NOS isoform expression, particularly neuronal NOS. SNAC (S-nitroso-N-acetylcysteine) administration (0.51 micromol/kg/day i.p. for 15 days) decreased the extent of the plaque by 55% in hypercholesterolemic mice, but had no effects on vasomotor changes. It did, however, lead to a decrease in constitutive NOS expression. The SNAC induced only minor changes in plasma lipid profile. CONCLUSION: The present study has shown that, in early stages of plaque development in LDLr-/- mice, specific changes in NO/NO synthase system develop, that are characterized by increased endothelium-dependent vasorelaxation and increased constitutive NOS expression. Since the development of plaque and the indicator of endothelial cell dysfunction were prevented by SNAC, such treatment may constitute a novel strategy for the halting of progression of early plaque.

Topically applied S-nitrosothiol-containing hydrogels as experimental and pharmacological nitric oxide donors in human skin.

BACKGROUND: Nitric oxide (NO) has a wide range of functions in the skin, and topical NO donors have several potential clinical applications. However, currently available donors are either unstable on the skin surface, release low concentrations of NO, or have a short duration of action. Endogenous S-nitrosothiols (RSNOs) store and transport NO within the body and can be used as exogenous sources of NO. OBJECTIVES: To study in vitro and in vivo the chemical and biological behaviour of two RSNO species, S-nitrosoglutathione (GSNO) and S-nitroso-N-acetylcysteine (SNAC), in an easily applied hydrogel, and to correlate dermal nitrite concentration with erythema following application of the RSNOs. To assess the suitability of GSNO and SNAC as biologically effective NO donors for clinical research and as potential therapeutic agents. METHODS/PATIENTS: GSNO (0.3 mol g(-1)) and SNAC (0.6 mol g(-1)) were incorporated in Synperonic F-127 hydrogels (Uniquema, Belgium). The in vitro kinetics of decomposition were measured by spectrophotometry at 37 degrees C. The RSNO-containing hydrogels were applied to the forearm skin of eight subjects. Blood flow was measured by laser Doppler for 3 h following application of NO donors and dermal nitrite simultaneously measured in microdialysate in four subjects. RESULTS: The mean peak blood flow achieved was 250. At blood flow values of < 250, dermal nitrite correlated closely with blood flow and could be defined by the equation: blood flow = (nitrite concentration x 0.66) + 120, (P = 0.013). At higher blood flows there was a paradoxical fall in dermal nitrite concentration. CONCLUSIONS: Topical RSNOs produce a consistent, sustained and biologically effective release of NO on human skin in vivo, which offers advantages over currently available topical NO donors. Dermal nitrite concentration--the oxidation product of NO--is directly correlated with blood flow at low and moderate levels of blood flow. At high levels of blood flow, there is a reduction in dermal nitrite, which is presumed to be due to increased blood scavenging.