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Biomedical subjects

Fei Luo

Publications and source records attributed to Fei Luo.

At least 19 recordsLinked to original sources
PubMed2026

A genetic signal at 8q12.3 modulates GGT levels via the Runx1-CYP7B1 axis in female ethnic minorities from Guizhou.

Gamma-glutamyl transferase (GGT) regarded as a biomarker of liver dysfunction or excessive alcohol consumption; however, existing genome-wide association studies (GWAS) have been conducted predominantly in European populations and East Asian populations from Japan and the Taiwan region, with limited investigation in ethnic minorities from Guizhou Province. Previous genetic studies have demonstrated that Guizhou ethnic minorities share an East Asian genetic background while exhibiting specific genetic structures, a pattern that is also confirmed by our principal component analysis (PCA) results. We therefore performed a GWAS in this population and identified a genome-wide significant signal at 8q12.3 in female ethnic minorities from Guizhou. Fine-mapping and functional annotation analyses suggest that a regulatory pathway involving Runt-related transcription factor 1 (Runx1)-Cytochrome P450 family 7 subfamily B member 1 (CYP7B1)-cholesterol-reactive oxygen species (ROS)-glutathione (GSH) may contribute to the regulation of GGT levels. Mendelian randomization (MR) analyses further supported a causal relationship between GGT levels and autoimmune hepatitis (AIH). These findings uncover a genetic mechanism underlying GGT variation at 8q12.3 in female ethnic minorities from Guizhou, implicating a pathway linked to cholesterol metabolism and oxidative stress, and providing potential targets and insights for precision prevention and treatment of related diseases.

Female↗
PubMed2006

Temporal sequence of ictal discharges propagation in the corticolimbic basal ganglia system during amygdala kindled seizures in freely moving rats.

We used a multiple channel, single unit recording technique to investigate the neural activity in different corticolimbic and basal ganglia regions in freely moving rats before and during generalized amygdala kindled seizures. Neural activity was recorded simultaneously in the sensorimotor cortex (Ctx), hippocampus, amygdala, substantia nigra pars reticulata (SNr) and the subthalamic nucleus (STN). We observed massive synchronized activity among neurons of different brain regions during seizure episodes. Neurons in the kindled amygdala led other regions in synchronized firing, revealed by time lags of neurons in other regions in crosscorrelogram analysis. While there was no obvious time lag between Ctx and SNr, the STN and hippocampus did lag behind the Ctx and SNr in correlated firing. Activity in the amygdala and SNr contralateral to the kindling stimulation site lagged behind their ipsilateral counterparts. However, no time lag was found between the kindling and contralateral sides of Ctx, hippocampus and STN. Our data confirm that the amygdala is an epileptic focus that emits ictal discharges to other brain regions. The observed temporal pattern indicates that ictal discharges from the amygdala arrive first at Ctx and SNr, and then spread to the hippocampus and STN. The simultaneous activation of both sides of the Ctx suggests that the neocortex participates in kindled seizures as a unisonant entity to provoke the clonic motor seizures. Early activation of the SNr (before the STN and hippocampus) points to an important role of the SNr in amygdala kindled seizures and supports the view that different SNr manipulations may be effective ways to control seizures.

Amygdala↗
PubMed2006

Basal ganglia neural responses during behaviorally effective deep brain stimulation of the subthalamic nucleus in rats performing a treadmill locomotion test.

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is an effective treatment for Parkinson's disease (PD). In spite of proven therapeutic success, the mechanism underlying the benefits of DBS has not been resolved. A multiple-channel single-unit recording technique was used in the present study to investigate basal ganglia (BG) neural responses during behaviorally effective DBS of the STN in a rat model of PD. Rats underwent unilateral dopamine (DA) depletion by injection of 6-hydroxyDA (6-OHDA) into one side of the medial forebrain bundle and subsequently developed a partial akinesia, which was assessed during the treadmill locomotion task. High frequency stimulation (HFS) of the STN restored normal treadmill locomotion behavior. Simultaneous recording of single unit activity in the striatum (STR), globus pallidus (GP), substantia nigra pars reticulata (SNr), and STN revealed a variety of neural responses during behaviorally effective HFS of the STN. Predominant inhibitory responses appeared in the STN stimulation site. Nearly equal numbers of excitatory and inhibitory responses were found in the GP and SNr, whereas more rebound excitatory responses were found in the STR. Mean firing rate did not change significantly in the STR, GP, and SNr, but significantly decreased in both sides of STN during DBS. A decrease in firing rate in the contralateral side of STN provides neural substrate for the clinical observation that unilateral DBS produces bilateral benefits in patients with PD. In addition to the firing rate changes, a decrease in burst firing was observed in the GP and STN. The present study indicates that DBS induces complex modulations of the BG circuit and further suggests that BG network reorganization, rather than a simple excitation or inhibition, may underlie the therapeutic effects of DBS in patients with PD.

Adrenergic Agents↗
PubMed2006

Dynamic optical limiting experiments on vanadium dioxide and vanadium pentoxide thin films irradiated by a laser beam.

Vanadium dioxide (VO2) and vanadium pentoxide (V2O5) thin films are irradiated by a near-infrared continuous-wave laser beam and the dynamic optical limiting performance is measured. The temperature varying with time of the films induced by a laser beam is also recorded by an IR thermal sensor. Under the irradiation of a laser beam with an intensity of 255 W/cm2 and a spot diameter of 2 mm, the laser beam transmittance of the VO2 film decreases from 47% before phase transition to 28% after phase transition, and the response time is approximately 200 ms; the laser beam transmittance of the V2O5 film decreases from 51% before phase transition to 24% after phase transition, and the response time is approximately 40 ms. The optical limiting is realized by this laser heating-induced phase transition.

Journal Article↗
PubMed2006

Deep brain stimulation of the substantia nigra pars reticulata exerts long lasting suppression of amygdala-kindled seizures.

Deep brain stimulation (DBS) has been used to treat a variety of neurological disorders including epilepsy. However, we have limited knowledge about effective target areas, optimal stimulation parameters, and long-term effect of DBS on epileptic seizures. Here we examined the effects of DBS of the substantia nigra pars reticulata (SNr) on amygdala-kindled seizures. Microwire electrodes were implanted into the SNr and amygdala of adult male rats. When stage 5-kindled seizures were achieved by daily amygdala kindling, high frequency stimulation was delivered to the SNr bilaterally 1 s after cessation of kindling. Our DBS protocol completely blocked kindled seizures in 10 out of 23 (43.5%) rats studied. Furthermore, when the same amygdala kindling procedure was performed 24 h later without DBS, the kindling failed to elicit any seizure signs in 6 of these 10 rats. Some of the post-DBS period of seizure suppression lasted for up to 4 days. In other 3 rats, only mild stage 1 to 2 seizures appeared following amygdala kindling. Only 1 of the 10 rats for which DBS had blocked kindled seizures exhibited full-scale 5 stage-kindled seizures 24 h after DBS. These results suggest that highly plastic neural networks are involved in amygdala-kindled seizures and that DBS, if well timed with the onset of amygdala kindling, may exert long lasting effects on the networks that may prevent the recurrence of kindled seizures.

Amygdala↗
PubMed2006

Dynamic neuronal responses in cortical and thalamic areas during different phases of formalin test in rats.

Although formalin-induced activity in primary afferent fibers and spinal dorsal horn is well described, the forebrain neural basis underlying each phase of behavior in formalin test has not yet been clarified. The present study was designed to investigate the cortical and thalamic neuronal responses and interactions among forebrain areas during different phases after subcutaneous injection of formalin. Formalin-induced neuronal activities were simultaneously recorded from primary somatosensory cortex (SI), anterior cingulate cortex (ACC) and medial dorsal (MD) and ventral posterior (VP) thalamus during different phases (i.e., first phase, interphase, second phase and third recovery phase starting from 70 min after injection) of formalin test, using a multi-channel, single-unit recording technique. Our results showed that, (i) unlike the responses in primary afferent fibers and spinal dorsal horn, many forebrain neurons displayed monophasic excitatory responses in the first hour after formalin injection, except a small portion of neurons which exhibited biphasic responses; (ii) the response patterns of many cortical and thalamic neurons changed from excitatory to inhibitory at the end of the second phase; (iii) the direction of information flow also changed dramatically, i.e., from cortex to thalamus and from the medial to the lateral pathway in the first hour, but reversed in phase 3. These results indicate that the changes of activity pattern in forebrain networks may underlie the emerging and subsiding of central sensitization-induced pain behavior in the second phase of formalin test.

Action Potentials↗
PubMed2006

[Processing of spatial information by hippocampal place cells].

Hippocampal place cells can process the environmental inputs and make up a cognitive map in the hippocampus, or strengthen the synaptic connections within an association cortical cell assembly,thus creating a permanent engram for a spatial site. Outputs from the hippocampus are then integrated with other inputs within the nucleus accumbens and finally initiate a goal-directed behavior through the motor circuit.

Animals↗
PubMed2006

[A study on the interpolation algorithm for the serial-parallel robot-controlled HIFU].

According to the hardware characters of the high intensive focused ultrasound (HIFU) serial-parallel robots, this paper presents an algorithm of 2-grade interpolation scheme which includes the rough and fine interpolations. Both pre-acceleration and post-acceleration are employed to meet the restrictive requirements of coordinated dynamic performance and the detailed procedure of the interpolation algorithm is given too.

Algorithms↗
PubMed2005

Tramadol and dihydroetorphine produce synergistic analgesic effect and postpones acute opiate tolerance in rats.

The present study investigated whether a co-application of tramadol (TRA) and dihydroetorphine (DHE) would exert a synergy in analgesic effect and delay acute tolerance development. Intraperitoneal injection of TRA (in mg) and subcutaneous injection of DHE (in ng) were delivered in fixed proportions (1:6.25, 1:12.5, 1:25, 1:50, 1:100, and 1:200). The effect of analgesia was accessed by tail-flick test and analyzed with isobolographic analysis. For test of acute tolerance, six successive injections of either TRA (20 mg/kg) alone, DHE (1 000 ng/kg) alone, or a combination of TRA (20 mg/kg) and DHE (250 ng/kg) were administered. We found that (1) except for 1 mg : 6.25 ng and 1 mg : 50 ng, combinations, all the other ratios produced a significant synergy in their analgesic effect; (2) the effect of analgesia induced by repeated TRA plus DHE injections lasted significantly longer, indicating a slower onset of acute tolerance. These results indicate that TRA and DHE injections in certain dose ratios can induce synergistic analgesia, which is resistant against the development of acute tolerance.

Analgesics, Opioid↗
PubMed2005

Neural responses in multiple basal ganglia regions following unilateral dopamine depletion in behaving rats performing a treadmill locomotion task.

To investigate basal ganglia (BG) neural responses to dopamine (DA) depletion, multiple channel, single unit recording was carried out in freely moving rats performing a treadmill locomotion task. Single unit activity from 64 microelectrodes in the striatum (STR), globus pallidus (GP), subthalamic nucleus (STN) and substantia nigra pars reticulata (SNr) was recorded simultaneously before and after a unilateral DA lesion induced by microinjection of 6-hydroxydopamine (6-OHDA) into the medial forebrain bundle. The DA lesion resulted in an impairment of treadmill walking manifested by a significant decrease in swing time of both forelimbs. The stance time, however, increased significantly only in ipsilateral (good) forelimbs, reflecting compensatory changes in the good limb for motor deficits. Neural activity in the STR and GP ipsilateral to the lesion decreased during the 7-day period following the DA lesion. Conversely, an increase in spike discharges appeared in the ipsilateral SNr and STN several days after the DA lesion. Changes in the type of neural response associated with treadmill locomotion were also found in some neurons after DA depletion. Such changes were most prominent in the STR. Limb movement-related neural activity increased significantly mainly in the SNr. Additionally, neural responses to the tone cue associated with the onset of the treadmill diminished greatly in the lesioned side of the BG. Increased activity in SNr neurons is consistent with the concept that inhibition of thalamus contributes to hypokinesis in the absence of DA. Substantial decrease in striatal activity supports a concept that DA loss leads to a global suppression of recurrent cortical striatal thalamic activity that degrades normal information flow in Parkinson's diseases.

Action Potentials↗
PubMed2005

Coding of peripheral electrical stimulation frequency in thalamocortical pathways.

Frequency information of the environment is an important feature for sensory perception. It has been demonstrated that cortical and thalamic neurons exhibited frequency-specific responses to peripheral stimulation. In the present study, we investigated the effects of 1-100 Hz peripheral electrical stimulations on various thalamic and cortical areas in awake rats. We used chronically implanted microelectrode arrays to record neural activities from the anterior cingulate cortex, primary somatosensory cortex, and medial dorsal and ventral posterior thalamus. The results revealed that cortical and thalamic neurons exhibited frequency-specific responses at both single-neuron and ensemble levels. Clusters of neurons responded to different frequency ranges with changes of both the peak firing rates and the phases of the peak responses in a stimulation cycle. Partial directed coherence analysis showed that information flowing between these recorded areas is also enhanced or inhibited in some frequency-specific pattern during stimulation. These evidences suggest that central nervous system may code environmental frequency information mainly with the activation of selected neural circuits according to their own intrinsic electrical properties. These properties, in turn, may facilitate or inhibit their responses when stimulation with specific frequency information arrives.

Animals↗
PubMed2005

Production and properties of an inhibitor of the Pseudomonas autoinducer by Pseudomonas aeruginosa.

An inhibitor was found in the culture fluid of Pseudomonas aeruginosa PAO1, which could inhibit the activity of the Pseudomonas autoinducer (PAI). The maximal inhibitory activity occurred in stationary phase culture sup ernatant. The PAI inhibitor did not influence the cell growth and the PAI production by P. aeruginosa PAO1 when the PAI inhibitor was added into culture medium. The induced expression of lacZ in the reporter strain Agrobacterium tumefaciens NT1 was suppressed by this PAI inhibitor, whereas inhibition could be relieved by increasing the auto inducer concentration. The quorum sensing of P. aeruginosa was inhibited presumably by inhibiting the inducing activity of Pseudomonas autoinducer but not by inhibiting the production of Pseudomonas autoinducer. It was demonstrated that the structure of the PAI inhibitor was different from that of acyl-homoserine lactones.

4-Butyrolactone↗
PubMed2005

[Clinical value of ultrasound guided transperineal prostate biopsy in detecting prostate cancer].

OBJECTIVE: To report our experience of ultrasound guided transperineal 6-core prostate biopsy (UG6CPB) in the diagnosis of prostate cancer (PCa). METHODS: In a prospective study, we performed UG6CPB in 104 suspected PCa patients with tPSA more than 4 microg/L and analysed the positive rate and complications of the diagnostic approach. RESULTS: PCa was detected in 24 of the 104 patients (23%), with low grade Gleason 2 to 4 in 3 cases (12.5%), intermediate grade Gleason 5 to 7 in 15 (62.5%) and high grade Gleason 8 to 10 in the remaining 6 (25%). Complications included temporary hematuria in 5 patients (4.8%), mild postbiopsy perineal discomfort in 5 (4.8%) and fever in 4 (3.8%). TPSA > or =10 microg/L, fPSA > or = 2 microg/L, fPSA/tPSA < 0.16, PSAD > or = 0.2 and prostate volume < 40 ml were the significant influencing factors of biopsy positive rate (P < 0.05). CONCLUSION: UG6CPB is an exact and a safe way of detecting PCa.

Biopsy, Needle↗
PubMed2004

Repeated peripheral electrical stimulations suppress both morphine-induced CPP and reinstatement of extinguished CPP in rats: accelerated expression of PPE and PPD mRNA in NAc implicated.

Previous studies have shown that peripheral electrical stimulation (PES) can suppress morphine-induced conditioned place preference (CPP) and the reinstatement of extinguished CPP in the rat. The present study was performed to elucidate if preproenkephalin (PPE) and preprodynorphin (PPD) mRNAs in the nucleus accumbens (NAc) play a role in this event. Rats were trained with morphine for 4 days to establish CPP paradigm. They were then given 15-min test once a day for eight consecutive days for extinction trial. Twenty-four hours after the 8th session of extinction trials, rats were given peripheral electrical stimulation (PES) at 2 or 100 Hz once a day for 3 days, then a morphine-priming injection at a dose of 1, 2, or 4 mg/kg to reinstate the extinguished CPP. At the end of the experiment, PPE and PPD mRNA levels in the nucleus acccumbens (NAc) were determined by the semiquantitative RT-PCR technique. The results showed that PES at 2- and 100-Hz administered 30 min a day for 3 days suppressed both the expression of morphine-induced CPP and the reinstatement of extinguished CPP. PES at 2 Hz increased preproenkephalin (PPE) mRNA levels, whereas PES of 100 Hz that of preprodynorphin (PPD) mRNA levels in the NAc. These findings suggest that enkephalin and dynorphin in NAc may play important roles in the mechanisms underlying the inhibitory effect of PES on the expression and reinstatement of morphine-induced CPP in rats.

Analysis of Variance↗
PubMed2004

Differential modulation of nociceptive neural responses in medial and lateral pain pathways by peripheral electrical stimulation: a multichannel recording study.

It is well accepted that peripheral electrical stimulation (PES) can produce an analgesic effect in patients with acute and chronic pain. However, the neural basis underlying stimulation-induced analgesia remains unclear. In the present study, we examined the pain-related neural activity modified by peripheral stimulation in rats. The stimulation frequency of pulses applied to needle electrodes in the hindlimb was 2 Hz alternating with 100 Hz, with 0.6 ms pulse width for 2 Hz and 0.2 ms for 100 Hz. The intensity of the stimulation was increased stepwise from 1 to 3 mA with each 1-mA step lasting for 10 min. The nociceptive neural and behavioral responses were examined immediately after the termination of stimulation. Using a multiple-channel recording technique, we simultaneously recorded the activity of many single neurons located in the primary somatosensory and anterior cingulate cortex (ACC), as well as the ventral posterior and medial dorsal thalamus in behaving rats. Our results showed that peripheral electrical stimulation significantly reduced the nociceptive responses in ventroposterior thalamus and somatosensory cortex, indicating an inhibition of nociceptive processing. In contrast, the analgesic stimulation produced a significant increase in mediodorsal thalamus while a less significant decrease in cingulate cortex, reflecting a complicated effect associated with combined antinociceptive activation and nociceptive suppression. These results support the idea that peripheral electrical stimulation can ultimately alter the pain perception by specifically inhibiting the nociceptive transmission in the sensory pathway while mobilizing the antinociceptive action in the affective pathway, thus to produce pain relief.

Animals↗
PubMed2004

High-frequency stimulation of the subthalamic nucleus reverses limb-use asymmetry in rats with unilateral 6-hydroxydopamine lesions.

Deep brain stimulation (DBS) is a widely used clinical treatment for Parkinson's disease (PD). A rodent model of DBS is a necessary tool for understanding the neural mechanisms of this method. Our previous study showed that high-frequency stimulation (HFS) of the subthalamic nucleus (STN) improved treadmill locomotion in rats with unilateral 6-hydroxydopamine (6-OHDA)-induced lesions of nigrostriatal dopamine (DA) neurons. The present study tested DBS effects on limb-use asymmetry (LUA) during vertical/lateral exploration in a cylindrical chamber in rats with similar unilateral nigrostriatal DA lesions. Limb-use asymmetry assessment has been used to detect functional capacity over a wide range of dopamine depletion. Before lesioning, rats exhibited regular rearing activity and used both forelimbs equally often to support weight during exploration of the walls of the cylinder. After unilateral nigrostriatal DA lesioning, rats displayed reduced rearing activity and predominant use of the ipsilateral (good) forelimb to touch the wall. HFS of the STN, but not of other nearby regions surrounding the STN, in the lesioned rats restored normal rearing activity and reversed the limb-use asymmetry caused by the unilateral DA depletion. This study is consistent with the possibility that there can be beneficial effects of STN-DBS on behavioral impairments in unilateral DA-depleted rats and may suggest an appropriate rodent model for DBS study.

Animals↗