Effects of local administrations of tempol and diethyldithio-carbamic on peripheral nerve activity

We have recently shown that systemic administration of a superoxide dismutase mimetic, tempol, resulted in decreases in mean arterial pressure and heart rate along with a reduction in renal sympathetic nerve activity (RSNA). It has also been shown that these parameters are significantly increased by systemic administration of a superoxide dismutase inhibitor, diethyldithio-carbamic (DETC), indicating a potential role of reactive oxygen species in the regulation of RSNA. In this study, we examined the effects of local administrations of 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl (tempol) and DETC on RSNA in anesthetized rats. Either tempol or DETC was directly administered onto the renal sympathetic nerves located between the electrode and ganglion. Local application of tempol (10 microL, 0.17 to 1.7 mol/L, n=6) resulted in dose-dependent decreases in integrated RSNA (by -81+/-6% at 1.7 mol/L) without alterations in mean arterial pressure and heart rate. In contrast, DETC (10 microL, 0.17 to 1.7 mol/L, n=6) increased RSNA dose-dependently. The responses of RSNA to tempol and DETC were significantly greater in spontaneously hypertensive rats than in normotensive rats (n=6, respectively). Local application of sodium nitroprusside (1 mmol/L) or N(G)-nitro-L-arginine methyl ester (0.11 mol/L) altered neither basal RSNA nor tempol-induced reductions in RSNA (n=6 and 5, respectively). A voltage-gated potassium channel blocker, 4-aminopyridine (0.1 mol/L), significantly decreased basal RSNA (by -81+/-1%) and completely prevented DETC-induced increases in RSNA (n=5). These results suggest that reactive oxygen species play a role in the regulation of peripheral sympathetic nerve activity, and that at least part of this mechanism is mediated through voltage-gated potassium channels.     

Detection of Pathogen-Specific Antibodies by Loop-Mediated Isothermal Amplification

Loop-mediated isothermal amplification (LAMP) is a method for enzymatically replicating DNA that has great utility for clinical diagnosis at the point of care (POC), given its high sensitivity, specificity, speed, and technical requirements (isothermal conditions). Here, we adapted LAMP for measuring protein analytes by creating a protein-DNA fusion (referred to here as a “LAMPole”) that attaches oligonucleotides (LAMP templates) to IgG antibodies. This fusion consists of a DNA element covalently bonded to an IgG-binding polypeptide (protein L/G domain). In our platform, LAMP is expected to provide the most suitable means for amplifying LAMPoles for clinical diagnosis at the POC, while quantitative PCR is more suitable for laboratory-based quantification of antigen-specific IgG abundance. As proof of concept, we measured serological responses to a protozoan parasite by quantifying changes in solution turbidity in real time. We observed a >6-log fold difference in signal between sera from vaccinated versus control mice and in a clinical patient sample versus a control. We assert that LAMPoles will be useful for increasing the sensitivity of measuring proteins, whether it be in a clinical laboratory or in a field setting, thereby improving acute diagnosis of a variety of infections.     

Objective assessment of internal stress in children during dental treatment by analysis of autonomic nervous activity

International Journal of Paediatric Dentistry 2012; 22: 331–341 Aims. The aim of this study was to assess the internal stress of children during dental treatment based on autonomic nerve activity and facial muscle activity. Methods. We recorded the electrocardiogram of children during the treatment of composite resin restoration and analysed autonomic nerve activity by means of power spectral analysis of heart rate variability. Simultaneously, electromyography (EMG) activity of the corrugator muscle was recorded in children during dental treatment, and the relationship between sympathetic nerve activity and corrugator EMG activity was analysed. Results. In all subjects, the mean sympathetic nerve activity was significantly higher during oral examination and after treatment compared with pre‐treatment. Depending on the sympathetic nerve responses to the other treatment procedures, the subjects could be classified into two groups: the stress group and the nonstress group. Sympathetic nerve activity was significantly higher during infiltration anaesthesia and cavity preparation compared with pre‐treatment activity in the stress group, whereas it was consistently lower than the pre‐treatment levels during most treatment procedures in the nonstress group. The mean amplitudes of the averaged corrugator muscle EMG during dental treatment did not differ between the stress and nonstress groups. Conclusion. The present results suggest that the measurement of autonomic nervous activity, especially sympathetic nervous activity, is quite useful in assessing the internal stress of children, even when no expressed sign of unease are present during dental treatment.     

The effect of nonfunctional tooth contact on sensory and pain perception in patients with myofascial pain of the jaw muscles

PurposeThe aim of this study was to examine the effect of nonfunctional tooth contact on sensory threshold (tactile detection threshold: TDT) and pain thresholds (filament-prick pain detection threshold: FPT; pressure pain threshold: PPT) in the orofacial region of patients with myofascial pain of the jaw muscles.MethodsThe study was performed on 36 subjects: 20 normal subjects and 16 patients. Using a stair-case method, TDT and FPT were measured by Semmes–Weinstein monofilaments, on the cheek skin (CS) overlying the masseter muscles (MM) and on the skin overlying the palm side of the thenar skin (TS). PPT was measured at the central part of the MM using a pressure algometer. Each parameter was measured before and after keeping light tooth contact for 5 min (session 1) and keeping the jaw relaxed for 5 min (session 2) as a control.ResultsThere were significant effects of experimental condition (before–after 5 min) on the TDT and FPT at several sites: after 5 min, TDT was higher in all measurement sites except the left CS of the patients in session 2. As for the FPT, the reactions between CS and TS were quite opposite in both sessions: after 5 min, the FPT at the CS decreased and/or remained, but the FPT at the TS increased and/or remained. Significant session effects (session 1–session 2) were only found on the FPT at the CS in patients.ConclusionSensitivity to FPT was more susceptible to tooth contact condition, especially in the patients.