Tyrosinase inhibition prevents non-coplanar polychlorinated biphenyls and polybrominated diphenyl ethers-induced hyperactivity in developing zebrafish: Interaction between pigmentation and neurobehavior.

Non-coplanar polychlorinated biphenyl (PCB) mixture Aroclor 1254 and polybrominated diphenyl ether (PBDE) BDE-47 are known to impede neurogenesis and neuronal development. We previously reported that exposure to PCB and PBDE leads to increased embryonic movement in zebrafish by decreasing dopamine levels. In this study, we studied the connection between the melanin and dopamine synthesis pathways in this context. Both genetic and chemical inhibition of tyrosinase, the rate-limiting enzyme in melanin synthesis, not only led to reduced pigmentation but also inhibit PCB/PBDE-induced embryonic hyperactivity. Furthermore, PCB and PBDE rarely affected tyrosinase expression in the potential pigment cells, suggesting that these compounds reduce dopamine through enzymatic regulation, including a competitive interaction for the substrate tyrosine. Our results provide new insights into the interactions between melanogenesis and dopaminergic neuronal activity, which may contribute to understanding the mechanisms underlying PCB/PBDE toxicity in developing organisms.

Physical and psychological recovery after vaginal childbirth with and without epidural analgesia: A prospective cohort study.

BACKGROUND: Enhanced recovery is the gold standard in modern perioperative management, including that for cesarean deliveries. However, qualitative and quantitative data on the physical and psychological recovery of women after vaginal childbirth are limited. Whether neuraxial labor analgesia influences postpartum recovery is unknown. METHODS: Primiparous women anticipating a vaginal childbirth between January 2020 and May 2021 were enrolled. Women with major comorbidities or postpartum complications and those who underwent a cesarean delivery were excluded. Daily step count was measured using a wrist-worn activity tracker (FitbitTM Inspire HR) for 120 hours after vaginal childbirth. Subjective fatigue levels and health-related quality of life were assessed using the Multidimensional Fatigue Inventory (MFI) and EuroQol 5 Dimension 5 Level (EQ-5D-5L), respectively, at the 3rd trimester antenatal visit, on postpartum day 1 and 3, and at the one-month postpartum visit. Rest and dynamic pain scores and the location of pain were documented by participants during postpartum hospitalization. RESULTS: Among 300 women who were enrolled antenatally, 95 and 116 had a vaginal delivery without (NCB group) and with (EPL group) epidural analgesia, respectively. The median number of steps per 24 hours increased daily in both groups, and no significant difference was detected between the groups. Postpartum pain was mild overall, with median rest and dynamic pain scores being less than 4 and similar between the groups. MFI and EQ-5D-5L scores were the worst on postpartum day 1 in both groups and gradually improved to antepartum level by the one-month postpartum visit. Higher MFI score on postpartum day 1, but not the use of epidural analgesia, was associated with lower odds of achieving adequate postpartum ambulation (defined as >3500 steps between 48 and 72 hours postpartum). CONCLUSION: The use of epidural analgesia was not associated with worse recovery outcomes during postpartum hospitalization. TRIAL REGISTRATION: UMIN-CTR, #UMIN000039343, registered on January 31, 2020.

[Reliability of the measurement of current perception thresholds in the palatal mucosa].

PURPOSE: The purpose of this study was to investigate the possibility of applying measurement of the Current Perception Threshold (CPT) to the oral mucosa. METHODS: Forty healthy volunteers (20 males and 20 females; mean age, 29.5 +/- 5.1 years) were recruited for the study. CPT measurements were performed over the nasopalatine nerve area and greater palatine nerve area with 5,250 and 2000 Hz electrical stimulation using the Neurometer NS3000. The CPTs were measured on three separate days, and each measurement was carried out once a day by a single operator. RESULTS: Each of the electrical stimulations of 5,250 and 2000 Hz had a specific CPT. There were no significant differences in the CPT values measured over the three days. The CPTs were lower in the females than in the males. There were no significant differences in the CPTs in the greater palatine nerve area between the right and the left side. No order effect was observed on the CPTs in the greater palatine nerve area of either side in the first and second measurements. The intraclass correlation coefficient of the CPT measurements was as high as 0.80. CONCLUSION: It was concluded based on the high reliability of the measurements obtained, that CPT measurement can be applied to the oral mucosa.

Perception thresholds for electrical stimulation of the palatal mucosa.

PURPOSE: To define the normative ranges of the Current Perception Threshold (CPT) of the palatal mucosa and to correlate it with the subjects' attributes. MATERIALS AND METHODS: A group of 129 informed healthy subjects consented to participate in the study. A Neurometer NS3000 device was used to evaluate the CPTs of the nasopalatine nerve (NPN) and the greater palatine nerve (GPN) by using 2000-, 250-, and 5-Hz stimulations. After confirming the relationships with regard to gender, age, weight, height, alcohol consumption, duration of sleep, weight percentage of water content, smoking, and CPT, the normative ranges of the CPT measurements were obtained. RESULTS: Correlations were observed between age and CPTs obtained with the 2000- and 250-Hz stimulations of the GPN. The CPTs of the GPN were higher than those of the NPN. With the exception of the 5-Hz stimulation of the NPN, the CPTs in men were higher than those in women; however, the within- and between-site ratios exhibited no differences between the male and female subjects. No significant effects of smoking and alcohol consumption on CPT were observed. Range analysis revealed an increase in the CPTs as the frequency increased from 5 to 250 to 2,000 Hz. Within-site ratio analysis revealed increasing and spreading CPT ratios in the following order: 250/5 Hz, 2000/250 Hz, and 2,000/5 Hz. In the order of 5-, 250-, and 2000-Hz stimulations, decreasing ratios were observed for the between-site ratio analysis. CONCLUSION: This study provides useful diagnostic criteria for CPTs in the palatal mucosa.

Randomized controlled clinical trial for verifying the effect of silicone-based resilient denture liner on the masticatory function of complete denture wearers.

PURPOSE: The purpose of this study was to investigate whether application of permanent silicone-based resilient denture liner (SR) to mandibular complete dentures significantly improves patients' masticatory ability compared to conventional heat-activated acrylic resin (AR). MATERIALS AND METHODS: Twenty-eight edentulous patients were randomly placed into 1 of 2 crossover groups (AR-SR/SR-AR) by using a random permuted block within strata method. The AR-SR group received AR denture treatments followed by SR denture treatments. The SR-AR group received treatments in the reverse sequence. The outcomes were classified by matiscatory performance, mandibular movement, electromyographic activity, and maximum occlusal force. RESULTS: No significant differences were observed in any of the baseline characteristic measurements between groups. SR denture wearers exhibited significantly higher masticatory performance than AR denture wearers. SR denture wearers exhibited a longer early-stage occluding period than AR denture wearers. There were no differences in electromyographic activity between the AR and SR groups. There were no significant differences in maximum occlusal force between the AR and SR groups. CONCLUSION: This study showed that the application of SR to mandibular complete dentures resulted in significant improvements to the patients' masticatory ability compared to AR.