BACKGROUND: Retrorsine (RS) is a chemical agent for the long-term inhibition of mature liver cell division and proliferation. OBJECTIVE: To establish a rat model of liver injury by combined use of RS and 1/3 partial hepatectomy, to observe the proliferation of liver cells and oval cells in rats after liver injury, and to discuss the relationship between liver regeneration and mature liver cells and oval cells after liver injury. METHODS: Thirty male Sprague-Dawely rats were randomized into two groups (n=15 per group): RS group and control group. Rats in the RS group were subjected to intraperitoneal injection of RS, 30 mg/kg, twice in total, with 2 weeks in between; and rats in the control group were injected physiological saline instead of RS. Four weeks after the last injection, the 1/3 partial hepatectomy was performed in two groups of rats. Liver pathological and morphological changes as well as cell proliferation were observed, and CK19 and C-kit immunohistochemical detections of the rat liver in the two groups were conducted at different time points after operation. RESULTS AND CONCLUSION: At 20 days after operation, the body mass of the RS group rats was still lower than the baseline, and the liver increase was obviously less than that in the control group; there was cell body swelling shown by hematoxylin-eosin staining, loose cytoplasm, extensive vacuoles degeneration of liver cells, and clustered or scattered oval cells around the portal area of small bile duct and in the hepatic lobule. However, in the control group, the body mass was close to the baseline, liver damage was lighter than that in the RS group, a large number of mature liver cells proliferated under BrdU Immunofluorescence at 20 days after operation; liver oval cells proliferated and distributed in the liver cell line at 14 days after operation, with morphology and immunohistochemical markers consistent with oval cells in the RS group. These findings indicate that the rat model of acute liver injury is successfully established by combining retrorsine with 1/3 partial hepatectomy, liver poisoning and the proliferation of liver stem cells and mature liver cells after poisoning can be seen in the experiment, which firmly confirm that liver cell renewal and regeneration after injury is accredited to the combined action of liver stem cells in liver basin and mature liver cells.

Objective To study the prevalence and distribution of mental disorders among registered and non-registered residents in Shenzhen. Methods An epidemiological survey on mental disorders were carried out in Shenzhen by stratified multi-stage randomized sampling method; 7134 respondents were assessed through face-to-face interview, using the WHO standardized version on World Mental Health (WMH) Survey Initiative of the Composite International Diagnostic Interview (CIDI3.1). Results (1)The weighting prevalence of mental disorders was 21.87%. The prevalence of non-registered residents was significantly higher than that of the registered residents (22.34% vs. 19.99% ; OR= 1.15,95%CI: 1.03-1.29; P<0.05) and the prevalence of females was significantly higher than that of males (22.68% vs. 19.67%; OR=1.20,95%CI: 1.07-1.34; P<0.05). The weighting prevalence of mood disorders, anxiety disorders and psychoses were 9.62%, 14.45% and 1.40%, respectively. (2) The weighting twelve-month incidence of mental disorders was 13.42%. The incidence of non-registered residents was significantly higher than that of the registered residents (13.80% vs. 11.90%; OR=1.19, 95%CI: 1.03-1.36; P<0.05). (3)The co-morbidity rate between mental disorders was 35.76%. (4)The prevalence and severity of mental disorders were associated with sex, household situation of registration, marital status, education, economic condition and occupation status. Conclusion Mental disorders have become common diseases and serious public health problem in Shenzhen, with non-registered residents and females deserve more attention.

Spinal cord magnetic resonance imaging (MRI) is an advanced imaging technique (mainly in the cervical cord) and has been gradually used in basic scientific research such as human sensation and motor function, and clinical applications such as spinal cord injury, myelitis, and chronic pain, etc. The development of spinal cord MRI is still at the early stage compared with brain MRI and limited by the current MRI technology and data analysis methods. This review focuses on the methods and applications of spinal cord MRI technology in the basic research fields of cognitive neuroscience and clinical application. Firstly, we will introduce the imaging principle, methods, measurement standards, and applications of most commonly used multimodal spinal cord MRI techniques, including quantitative spinal cord MRI (such as structural, diffusion, spectroscopy, myelin water, magnetization transfer, and chemical exchange saturation transfer imaging, etc.) and spinal functional MRI (fMRI). Secondly, we will discuss the technical challenges and possible solutions of spinal cord MRI data processing from the three dimensions of denoising, data processing pipeline optimization, and repeatability and reliability. Finally, we will discuss the application status and development prospects of spinal cord MRI.
Humans ; Magnetic Resonance Imaging ; Magnetic Resonance Spectroscopy ; Reproducibility of Results ; Spinal Cord/diagnostic imaging* ; Spinal Cord Injuries

The somatosensory system, including modalities such as touch, temperature, and pain, is essential for perceiving and interacting with the environment. When individuals encounter different somatosensory modalities, they interact through a process called multimodal somatosensory integration. This integration is essential for accurate perception, motor coordination, pain management, and adaptive behavior. Disruptions in this process can lead to a variety of sensory disorders and complicate rehabilitation efforts. However, research on the behavioral patterns and neural mechanisms underlying multimodal somatosensory integration remains limited. According to previous studies, multimodal somatosensory integration can result in facilitative or inhibitory effects depending on factors like stimulus type, intensity, and spatial proximity. Facilitative effects are observed primarily when stimuli from the same sensory modality (e.g., two touch or temperature stimuli) are presented simultaneously, leading to amplified perceptual strength and quicker reaction times. Additionally, certain external factors, such as cooling, can increase sensitivity to other sensory inputs, further promoting facilitative integration. In contrast, inhibitory effects may also emerge when stimuli from different sensory modalities interact, particularly between touch and pain. Under such conditions, one sensory input (e.g., vibration or non-noxious temperature stimulation) can effectively reduce the perceived intensity of the other, often resulting in reduced pain perception. These facilitative and inhibitory interactions are critical for efficient processing in a multi-stimulus environment and play a role in modulating the experience of somatosensory inputs in both normal and clinical contexts. The neural mechanisms underlying multimodal somatosensory integration are multi-tiered, encompassing peripheral receptors, the spinal cord, and various cortical structures. Facilitative integration relies on the synchronous activation of peripheral receptors, which transmit enhanced signals to higher processing centers. At the cortical level, areas such as the primary and secondary somatosensory cortex, through multimodal neuron responses, facilitate combined representation and amplification of sensory signals. In particular, the thalamus is a significant relay station where multisensory neurons exhibit superadditive responses, contributing to facilitation by enhancing signal strength when multiple inputs are present. Inhibitory integration, on the other hand, is mediated by mechanisms within the spinal cord, such as gating processes that limit transmission of competing sensory signals, thus diminishing the perceived intensity of certain inputs. At the cortical level, lateral inhibition within the somatosensory cortex plays a key role in reducing competing signals from non-target stimuli, enabling prioritized processing of the most relevant sensory input. This layered neural architecture supports the dynamic modulation of sensory inputs, balancing facilitation and inhibition to optimize perception. Understanding the neural pathways involved in somatosensory integration has potential clinical implications for diagnosing sensory disorders and developing therapeutic strategies. Future research should focus on elucidating the specific neural circuitry and mechanisms that contribute to these complex interactions, providing insights into the broader implications of somatosensory integration on behavior and cognition. In summary, this review highlights the importance of multimodal somatosensory integration in enhancing sensory perception. It also underscores the need for further exploration into the neural underpinnings of these processes to advance our understanding of sensory integration and its applications in clinical settings.

Nicotine is the main addictive component in cigarettes that motivates dependence on tobacco use for smokers and makes it difficult to quit through regulating a variety of neurotransmitter release and receptor activations in the brain. Even though nicotine has an analgesic effect, clinical studies demonstrated that nicotine abstinence reduces pain threshold and increases pain sensitivity in smoking individuals. The demand for opioid analgesics in nicotine abstinent patients undergoing surgery has greatly increased, which results in many side effects, such as nausea, vomiting, and respiratory depression, etc. In addition, these side effects would hinder patients' physical and psychological recovery. Therefore, identifying the neural mechanism of the increase of pain sensitivity induced by nicotine abstinence and deriving a way to cope with the increased demand for postoperative analgesics would have enormous basic and clinical implications. In this review, we first discussed different experimental pain stimuli (e.g., cold, heat, and mechanical pain)-induced pain sensitivity changes after a period of nicotine dependence/abstinence from both animal and human studies. Then, we summarized the effects of the brain neurotransmitter release (e.g., serotonin, norepinephrine, endogenous opioids, dopamine, and γ-aminobutyric acid) and their corresponding receptor activation changes after nicotine abstinence on pain sensitivity. Finally, we discussed the limits in recent studies. We proposed that more attention should be paid to human studies, especially studies among chronic pain patients, and functional magnetic resonance imaging might be a useful tool to reveal the mechanisms of abstinence-induced pain sensitivity changes. Besides, considering the influence of duration of nicotine dependence/abstinence and gender on pain sensitivity, we proposed that the effects of nicotine abstinence and individual differences (e.g., duration of abstinence from smoking, chronic/acute abstinence, and gender) on abstinence-induced pain sensitivity should be fully considered in formulating pain treatment protocols. In summary, this paper could deepen our understanding of nicotine abstinence-induced pain sensitivity changes and its underlying neural mechanism, and could also provide effective scientific theories to guide clinical pain diagnosis and treatment, which has important clinical significance.
Animals ; Humans ; Nicotine/adverse effects* ; Pain ; Pain Threshold ; Smoking Cessation ; Tobacco Use Disorder