Postoperative delirium, neuroinflammation, and influencing factors of postoperative delirium: A review

Postoperative delirium (POD) is an acute cognitive dysfunction that is mainly characterized by memory impairment and disturbances in consciousness. POD can prolong the hospital stay and increase the 1-month mortality rate of patients. The overall incidence of POD is approximately 23%, and its prevalence can go up to 50% in high-risk surgeries. Neuroinflammation is an important pathogenic mechanism of POD that mediates microglial activation and leads to synaptic remodeling. Neuroinflammation, as an indispensable pathogenesis of POD, can occur due to a variety of factors, including aseptic inflammation caused by surgery, effects of anesthetic drugs, disruption of the blood-brain barrier, and epigenetics. Understanding these factors and avoiding the occurrence of risk factors may help prevent POD in time. This review provides a brief overview of POD and neuroinflammation and summarizes various factors affecting POD development mediated by neuroinflammation, which may serve as future targets for the prevention and treatment of POD.

Identification of insecticidal constituents of the essential oil of Acorus calamus rhizomes against Liposcelis bostrychophila Badonnel

The aim of this research was to determine the chemical composition of the essential oil of Acorus calamus rhizomes, its insecticidal activity against the booklouse, (Liposcelis bostrychophila) and to isolate any insecticidal constituents from the essential oil. The essential oil of A. calamus rhizomes was obtained by hydrodistillation and analyzed by GC-FID and GC-MS. A total of 32 components of the essential oil of A. calamus rhizomes was identified and the principal compounds in the essential oil were determined to be α-asarone (50.09%), (E)-methylisoeugenol (14.01%), and methyleugenol (8.59%), followed by β-asarone (3.51%), α-cedrene (3.09%) and camphor (2.42%). Based on bioactivity-guided fractionation, the three active constituents were isolated from the essential oil and identified as methyleugenol, (E)-methylisoeugenol and α-asarone. The essential oil exhibited contact toxicity against L. bostrychophila with an LD₅₀ value of 100.21 µg/cm² while three constituent compounds, α-asarone, methyleugenol, and (E)-methylisoeugenol had LD₅₀ values of 125.73 µg/cm², 103.22 µg/cm² and 55.32 µg/cm², respectively. Methyleugenol and (E)-methylisoeugenol possessed fumigant toxicity against L. bostrychophila adults with LC₅₀ values of 92.21 μg/L air and 143.43 μg/L air, respectively, while the crude essential oil showed an LC₅₀ value of 392.13 μg/L air. The results indicate that the essential oil of A. calamus rhizomes and its constituent compounds have potential for development into natural fumigants/insecticides for control of the booklice.

Characteristic length scale of nanorod diameter during growth

This Letter proposes a characteristic length scale on surfaces and demonstrates its impact on nanorod growth. The proposed length scale is the dimension of a surface segment bounded by multiple-layer steps. Lattice kinetic Monte Carlo simulations, taking Cu as the prototype of nanorods, show that the proposed length scale (i) exists as the result of a diffusion barrier of adatoms down multiple-layer steps, (ii) dictates that the diameter of metallic nanorods is on the order of several hundred nanometers, and (iii) sets the upper limit of the facet dimension.

Development and application of medicinal plant tissue cultures for production of drugs and herbal medicinals in China

In the search for new drugs and natural remedies, medicinal plants or herbs used in folk and traditional medicines are promising candidates. For the naturally rare and slowly growing plant species, plant tissue culture in bioreactors provides a cost-effective, sustainable and well-controlled means for mass production of the active principles of medicinal plants, and enables fuller utilization of their biosynthetic capacity. Recognizing that natural resources and agricultural land in China are limited,many Chinese research groups have engaged in the development of plant tissue culture techniques and processes for the cultivation and rapid propagation of medicinal plants, and for the biosynthesis and biotransformation of phytomedicines. This review primarily aims to provide a comprehensive summary of the major achievements in this and related research areas in China over the last three decades, but also to identify the difficulties and predict future trends in developing plant tissue culture biotechnology for the manufacture of bioactive natural products.

Continuous monitoring of brain tissue oxygen pressure in patients with severe head injury during moderate hypothermia

BACKGROUND

We studied the change of brain tissue oxygen pressure (PbrO2) value within 24 hours after trauma and during moderate hypothermia in patients with severe head injury. The PbrO2 value was used to differentiate patients at risk of brain ischemia and to predict outcome.

METHODS

A flexible microcatheter to be used for continuous monitoring of brain tissue oxygen was inserted into the normal frontal white matter, along with a thermocouple, in 14 patients with severe head injury within 1.5-12 hours (mean 6.1 +/- 5.2 hours) after trauma. Moderate hypothermia was also used within 24 hours in these patients.

RESULTS

(1) No complications related to the microcatheter were seen. (2) Low initial PbrO2 values (mean values <10 mmHg) were noted after severe head injury. (3) The occurrence of low initial PbrO2 values (< or = 5 mmHg) was significantly correlated with a poor outcome. (4) Moderate hypothermia can increase PbrO2, but hyperventilation reduced PbrO2. (5) The difference between RT and BT increased during moderate hypothermia.

CONCLUSIONS

The PbrO2 values were low in severe head injury, but hypothermia may improve these values. The technique of continuously monitoring brain tissue oxygen pressure may give better insight into cerebral oxygenation and warn of impending ischemia of brain tissue, especially in patients treated with hyperventilation. It will help to improve the management and final outcome of patients with severe head injuries.