Esketamine prevents propofol-induced injection pain: Randomized controlled trial.

Background: Propofol is widely used during anesthesia. However, propofol-induced injection pain (PIP) is considered an unpleasant perioperative outcome. This study aimed to investigate the efficacy of a mixture of esketamine and propofol in preventing propofol injection pain in patients undergoing general anesthesia. Methods: This was a prospective, double-blind, multicenter, and randomized controlled trial. We included 252 adult patients with the American Society of Anesthesiologists physical status I to II who underwent surgery under general anesthesia. Patients were randomly allocated in a 1:1:1:1 ratio to four groups (n = 63 per group). Group NS received a mixture of 1% propofol (20 ml) and 0.9% normal saline (1 ml), group ESK-4 received a mixture of 1% propofol (20 ml) and esketamine 4 mg (diluted with 0.9% normal saline, 1 ml), group ESK-12 received a mixture of 1% propofol (20 ml) and esketamine 12 mg (diluted with 0.9% normal saline, 1 ml), and group ESK-20 received a mixture of 1% propofol (20 ml) and esketamine 20 mg (diluted with 0.9% normal saline, 1 ml) as sedative drugs during anesthesia. The primary outcome was the incidence and distribution of different degrees of PIP. The secondary outcomes were vital signs, characteristics of surgery and anesthesia, and adverse events. Results: The incidence of PIP in group ESK-20 (33.3%) was significantly lower than that in groups NS, ESK-4, and ESK-12 (63.3%, 62.2%, and 49.1%, respectively; p < 0.01). The incidence of moderate PIP in group NS (33.3%) and group ESK-4 (22.6%) was higher than that in groups ESK-12 (7.5%) and ESK-20 (6.7%). The incidence of severe PIP in group NS (6.7%) and group ESK-4 (9.4%) was higher than that in groups ESK-12 (1.9%) and ESK-20 (0%). There were no differences in the vital signs, characteristics of surgery and anesthesia, or adverse events between the groups. Conclusion: Our results indicated that the esketamine-propofol admixture reduced the incidence of PIP in patients undergoing general anesthesia without severe side effects.

Diapause induction and termination in Hyphantria cunea (Drury) (Lepidoptera: Arctiinae).

The fall webworm, Hyphantria cunea (Drury), enters facultative diapause as a pupa in response to short-day conditions during autumn. Photoperiodic response curves showed that the critical day length for diapause induction was 14 h 30 min, 14 h 25 min and 13 h 30 min at 22, 25 and 28°C, respectively. The photoperiodic responses under non-24 h light-dark cycles demonstrated that night length played an essential role in the determination of diapause. Experiments using a short day length interrupted by a 1-h light pulse exhibited two troughs of diapause inhibition and the effect of diapause inhibition was greater in the early scotophase than in the late scotophase. The diapause-inducing short day lengths of 8, 10 and 12 h evoked greater intensities of diapause than did 13 and 14 h. Diapause can be terminated without exposure to chilling, but chilling at 5°C for 90 and 120 d significantly accelerated diapause development, reduced mortality, and synchronized adult emergence. Additionally, the potential for H. cunea from the temperate region (Qingdao) to emerge and overwinter under field conditions in subtropical regions (Nanchang) of China was evaluated. Pupae that were transferred to Nanchang in early July showed a 60% survival rate and extremely dispersed pupal period (from 12 to 82 days), suggesting that some pupae may undergo summer diapause. Diapausing temperate region pupae that were moved out-of-doors in Nanchang during October showed approximately 20% overwintering survival; moreover, those pupae that overwintered successfully emerged the next spring during a period when their host plants would be available. The results indicate that this moth has the potential to expand its range into subtropical regions of China.

A comparison of photoperiodic control of diapause between aestivation and hibernation in the cabbage butterfly Pieris melete.

In the cabbage butterfly, Pieris melete, summer and winter diapause are induced principally by long and short daylengths, respectively; the intermediate daylengths (12-13 h) permit pupae to develop without diapause. In this study, photoperiodic control of summer and winter diapause was systematically investigated in this butterfly by examining the photoperiodic response, the number of days required to induce 50% summer and winter diapause and the duration of diapausing pupae induced under different photoperiods. Photoperiodic response curves at 18 and 20 degrees C showed that all pupae entered winter diapause at short daylengths (8-11 h), the incidence of diapause dropped to 82.3-85.5% at 22 degrees C without showing a significant difference between short daylengths, whereas the incidence of summer diapause induced by different long daylengths (14-18 h) was varied and was obviously affected by temperature. By transferring from various short daylengths (LD 8:16, LD 9:15, LD 10:14 and LD 11:13) to an intermediate daylength (LD 12.5:11.5) at different times after hatching, the number of cycles required to induce 50% winter diapause (7.28 at LD 8:16, 7.16 at LD 9:15, 7.60 at LD 10:14 and 6.94 at LD 11:13) showed no significant difference, whereas by transferring from various long daylengths (LD 14:10, LD 15:9, LD 16:8 and LD 17:7) to an intermediate daylength (LD 12.5:11.5) at different times, the number of cycles required to induce 50% summer diapause (5.95 at LD 14:10, 8.02 at LD 15:9, 6.80 at LD 16:8, 7.64 at LD 17:7) were significantly different. The intensity of winter diapause induced under different short daylengths (LD 8:16, LD 9:15, LD 10:14 and LD 11:13) was not significantly different with an average diapause duration of 87 days at a constant temperature of 20 degrees C and 92 days at a mean daily temperature of 19.0 degrees C, whereas the intensity of summer diapause induced under different long daylengths (LD 14:10, LD 15:9, LD 16:8 and LD 17:7) was significantly different (the diapause duration ranged from 75 to 86 days at a constant temperature of 20 degrees C and from 76 to 88 days at a mean daily temperature of 19.0 degrees C). All results suggested that photoperiodic control of diapause induction and termination is significantly different between aestivation and hibernation.

Photoperiodic clock of diapause induction in Pseudopidorus fasciata (Lepidoptera: Zygaenidae).

Pseudopidorus fasciata enters diapause as fourth instar larvae at short day lengths. Using 24-h light-dark cycles, the photoperiodic response curves in this species appeared to be similar with a critical night length of 10.5h at temperatures below 30 degrees C. At an average temperature of 30.5 degrees C, the critical night length had shifted to between 15 and 17h. In experiments using non-24-h light-dark cycles, it was clearly demonstrated that the dark period (scotophase) was the decisive phase for a diapause determination. In night interruption experiments using 24-h light-dark cycles, a 1-h light pulse at LD12:12 completely reversed the long night effect and averted diapause in all treatments. At LD 9:15 light pulses of 1-h, 30- or 15-min also averted diapause effectively when both the pre-interruption (D(1)) or the post-interruption scotophases (D(2)) did not exceed the critical night length. If D(1) or D(2) exceeded the critical night length diapause was induced. The most crucial event for the photoperiodic time measurement in this species is the length of the scotophase. A 10-min light pulse placed in the most photosensitive phase reversed diapause in over 50% of the individuals. Night interruption experiments under non-24-h light-dark cycles indicated that the photoperiodic clock measured only D(1) regardless of the length of D(2), suggesting that the most inductive cycles are often those in which L+D are close to 24h. In resonance experiments, this species showed a circadian periodicity at temperatures of 24.5 or 26 degrees C, but not at 30.5 and 23.3 degrees C. On the other hand, Bünsow and skeleton photoperiod experiments failed to reveal the involvement of a circadian system in this photoperiodic clock. These results suggest the photoperiodic clock in this species is a long-night measuring hourglass and the circadian effect found in the final expression of the photoperiodic response in the resonance experiments may be caused by a disturbing effect of the circadian system in unnatural regimes.