Search

Objective: To explore the correlation between the attachment type of lateral pterygoid muscle (LPM) and the position of temporomandibular joint (TMJ) disc in patients with temporomandibular disorders (TMD) by using wireless amplified magnetic resonance imaging detector (WAND) coupled with conventional head and neck joint coil for high resolution imaging of TMJ. Methods: Eighty-five patients with TMD diagnosed by oral and maxillofacial surgeons of Guizhou Provincial People's Hospital from October 2019 to January 2022 were collected. A total of 160 TMJ were included. There were 16 males and 69 females, aged (32.7±14.2) years. All patients were scanned with open, closed oblique sagittal and coronal WAND coupled head and neck coils with bilateral TMJ. Based on TMJ and LPM high resolution imaging, to explore the correlation between LPM attachment types and the position of TMJ disc in TMD patients, and to evaluate the potential clinical value of LPM attachment types in TMD patients. χ 2 test and Pearson correlation analysis were used to evaluate the correlation between LPM attachment type and TMJ disc location. Results: There were three types of LPM attachment: type Ⅰ in 51 cases [31.9% (51/160)], type Ⅱ in 77 cases [48.1% (77/160)] and type Ⅲ in 32 cases [20.0% (32/160)]. There was a significant correlation between the type of LPM attachment and the position of articular disc ( χ 2 =28.20, P =0.002, r =0.776). There was no statistical significance between the type of LPM attachment and the reversible displacement of articular disc ( χ 2 =0.24, P =0.887, r =0.825). Conclusions: There is a correlation between the attachment type of LPM and the position of the disc in TMD patients. WNAD coupled with conventional head and neck joint coil TMJ high resolution scan can provide reliable imaging evidence for TMD patients in evaluating the type of LPM attachment and the location of disc.

This study used sampling analysis and a CAMx-PSAT coupling model to analyze the components, transmission, and source apportionment of PM 2.5 in Beijing and Tangshan in January 2018. The results showed that in January 2018, water-soluble inorganic ions (WSⅡs) accounted for 49.59% and 39.13% of PM 2.5 mass concentrations in Beijing and Tangshan, respectively. The ratios of NO 3 - to SO 4 2- were 2.02 and 1.51, respectively, indicating that pollution in both cities was dominated by mobile sources. In Beijing and Tangshan, PM 2.5 accounted for 48.74% and 30.67% of transmission, respectively. Regional transmissions were mainly contributed by neighboring areas, northwest masses, and southwest masses. However, the contribution of the southwest passage to pollution in the respective cities increased by 9.65% and 15.02% during pollution periods. The principal sources contributing to PM 2.5 pollution in Beijing were mobile and dust sources. Secondary ions were more obviously affected by regional contributions, mobile and industrial sources had the most significant effect in Tangshan, and most particulate matter and sulfate were contributed by local emissions. From 2013 to 2018, the dominant component of WSⅡs changed from sulfate to nitrate while the main pollution sources changed from coal-fired and industrial sources to mobile and dust sources. Meanwhile, in January 2018, the meteorological factors were more favorable for pollution mitigation than in 2013. The meteorological impact of secondary ions is closely related to the lower relative humidity in 2018, compared to 2013.

Extracellular vesicles are cell-to-cell communication tools that play important roles in sperm maturation, motility, and fertilization. Epididymosomes provide proteins, lipids, and genetic materials to sperm as the latter go through the epididymis, not only promoting sperm maturation, but also influencing sperm and offspring phenotypes at the epigenetic level. After ejaculation, prostasomes fuse with sperm, leading to changes in the composition of the sperm plasma membrane and the contents of sperm, which maintains the stability of the sperm plasma membrane and increases sperm motility as well. Uterosomes can enhance sperm capacitation and acrosome reaction. Oviductosomes participate in sperm capacitation and motility, provide non-coding RNA to sperm, and influence the development of embryos. However, studies on extracellular vesicles and spermatozoa are mostly based on animal experiments, and their applicability to humans remains to be further explored.

Objective: To investigate the prevalence and associated factors of chronic kidney diseases (CKD) in adult residents living in a community of Songjiang district, Shanghai. Methods: A total of 9 257 residents aged 20-75 years old in Xinqiao township of Songjiang district were selected by random cluster sampling. All the participants were interviewed to complete a set of personal questionnaire and undergo physical examinations. Urine and blood tests including markers of kidney damage and related associated factors with CKD, were carried out. Results: Eligible data from 8 207 subjects were enrolled in the study. After adjustment for age and gender, the prevalence of CKD was 8.4% (95 %CI : 7.8%-9.0%), with majority of the patients (76.5%) appeared in the early stage (Ⅰ and Ⅱ) of the disease. The prevalence of CKD increased with age and higher prevalence was seen in females than in males ( P <0.001). Results from logistic regression analysis showed that factors as: being elderly or female, having hypertension, hyperuricemia, and hyperlipidemia were all independently associated with CKD. Conclusions: The prevalence of CKD appeared relatively high in adult residents of Xinqiao township, Songjiang district where CKD had become a public health problem. Factors as: being female or elderly, hypertension, hyperuricemia, and hyperlipidemia were found to be associated with CKD. Our findings suggested that early prevention and control on CKD to reduce the incidence of end-stage renal diseases and related complications had called for more urgent attention.

Objective: To investigate the mRNA genomics changes and significance of important ion channel proteins in patients with atrial fibrillation (AF), to reveal the mechanism of electrical remodeling in AF. Methods: Ninety patients with AF were chosen to receive the radiofrequency ablation (AF-RFA), 90 healthy subjects were included as the normal control group.The coronary sinus blood and peripheral venous blood were taken from each AF patient during the operation of AF-RFA.The genome-wide mRNA expression profile was analyzed with mRNA microarray chip, and the mRNA expression difference results for the major ion channel gene was further validated using Real-time PCR test. Results: The expression of twelve ion channel protein mRNA increased ≥2.0-fold, expression of 10 mRNA decreased ≥2.0-fold, among which K(+) channel gene KCNE4, KCND2, KCNN4 declined obviously, KCNA5 dropped 11.54-fold ( P < 0.01); KCNS3, KCNS1, KCNG1, KCNG7 and Ca(+ +) channel gene CACNA2D3 increased significantly.Compared with autologous peripheral blood, 12 mRNAs of ion channel protein in coronary sinus blood of AF patients was differentially expressed ≥2.0-fold.Compared with control group in peripheral blood, 7 ion channel protein mRNA expression differences was ≥2.0-fold, and the KCNA5 gene expression was down by 8.13-fold.RT-PCR confirmed that the trend and extent of differential expression were consistent with the chip results.The results of myocardial tissue RT-PCR showed that CACNA1C, KCNC3, KCNG1 and KCNK7 mRNA were up-regulated in AF ( P <0.05), and other ion channel mRNA expressions were down-regulated ( P <0.05). KCNA5 was down-regulated most obvious. Conclusion: The down-regulation of KCNA5 gene expression in AF patients is most obvious, and more potassium ion channel expression differences are also significant, so that the potassium ion channel reconstruction may play a dominant or much more important role in AF electrical remodeling.

Objective: To compare the value of two 3D imaging reconstruction methods for left atria and pulmonary vein on guiding the catheter ablation for atrial fibrillation (AF). Methods: From January 2014 to January 2017, a total of 100 drug refractory paroxysmal AF patients were divided into left atria direct angiography group ( n =50), and indirect angiography group ( n =50). 3D CARTO system was applied for mapping and guiding the ablation procedure. Patients assigned to direct angiography group were treated as follows: intraoperative puncture of atrial septum, inject contrast agent directly into the left atrium, conduct left atrial and pulmonary venous rotation angiography, reconstruct three-dimensional image, integrate the image into real-time X-ray system to facilitate circumferential pulmonary vein isolation. Patients assigned into the indirect angiography group were treated as follows: inject contrast agent through the right ventricle, conduct delayed rotation angiography of the left atria and pulmonary vein to guide circumferential pulmonary vein fixation and ablation. The left atrial and pulmonary venous image acquisition, the operation and X-ray exposure time, the success rate and the incidence of complication of the two groups were compared. The patients were followed up for 3-6 months. Results: General clinical characteristics of the two groups were similar(all P >0.05). Ablation was successful in all 100 patients. The operation time[(112.0±21.4)min vs. (134.0±24.3)min]and X-ray exposure time((10.7±4.7)min vs. (15.8±5.2)min)were significantly lower in direct angiography group than in indirect angiography group (both P <0.01). There was no significant difference between the two groups in the immediate (86%(43/50) vs. 82%(41/50), P =0.59) and short-term (76%(38/50) vs. 72%(36/50), P =0.65) success rate and complication rate (1 aneurysm in the direct angiography group, 1 pericardial tamponade in the indirect angiography group). In-hospital mortality was zero percent. Conclusion: It is safe and effective method to guide the radiofrequency catheter ablation of paroxysmal atrial fibrillation by reconstruction 3D image of left atrium and pulmonary vein. Compared with indirect angiography group, direct angiography group can improve the imaging quality of left atrium and pulmonary vein, decrease the X-ray exposure time of the ablation procedure.

Objective: To explore the inhibitory effect of cinnamaldehyde on invasion capacities of human breast cancer cell line MDA-MB-435S and its relation with regulating the expression of miR-27a., Methods: The effect of cinnamaldehyde on invasive capacities of MDA-MB-435S was measured by Transwell matrigel invasion assay. The effect of miR-27a expression on invasive capabilities of MDA-MB-435S, the intervention of cinnamaldehyde in the miR-27a expression, and its relation with its effect on invasive capabilities were defected with liposome 2000 transinfection miRNA27a mimics/inhibitors, real time-polymerase chain reaction (Real-time PCR), and Transwell chamber model., Results: Compared with the control group, the number of cells passing through the transwell chamber was more significantly reduced after treated by cinnamaldehyde for 12 h (P < 0.05). The miR-27a expression was 962.07 times and 40% of that of the control group after transinfected by miR-27a mimics and miR-27a inhibitors. After transinfected by miR-27a inhibitors, the number of cells passing through the transwell chamber was more significantly reduced (P < 0.05). The miR-27a expression of MDA-MB-435S was down-regulated by 12-h treatment of cinnamaldehyde (2(-deltaCt) = 0.56, 0.18, 0.18, respectively). The number of miR-27a mimics transinfection pretreated MDA-MB-435S cells passing through the transwell chamber increased more obviously than the number of un-pretreated MDA-MB-435S cells in the control group (P < 0.05)., Conclusions: Cinnamaldehyde could inhibit invasive capabilities of human breast cancer cell line MDA-MB-435S. The over-expression of miR-27a played an important role in the invasive capability of MDA-MB-435S. The inhibition of cinnamaldehyde on invasive capabilities of MDA-MB-435S cells was correlated with down-regulating the expression of miR-27a.

Objective: To evaluate the effect of melittin and 5-Fu, DDP, and TXT on human gastric cancer cell line BGC-823 and to primarily explore their possible mechanisms., Methods: Median effect analysis was employed to determine the interaction between melittin and 5-Fu, DDP, TXT by analyzing the relationship between fraction affected (FA) and the combination index (CI) acquired from the dose-effect curve. Expressions of chemotherapeutic agent-associated genes of BGC-823 cells with or without treatment were measured by real-time fluorescent quantitative PCR., Results: (1) Both melittin and chemotherapeutic agents inhibited the growth of BGC-823. (2) For BGC-823 cells were acted by 5-Fu +melittin, when FA ranged between 0.35-0.75, CI was less than 1. For BGC-823 cells were acted by DDP + melittin, when FA ranged 0.55 or so, CI = 1; when Fa ranged below 0.55, CI was less than 1. For BGC-823 cells were acted by TXT + melittin, CI less than 1 could be seen in the whole interval. (3) After treatment suppressed were the expressions of chemotherapeutic agent-associated genes of BGC-823 cells such as thymidylate synthetase (TS), excision repair cross-complementing gene 1 (ERCC1), breast cancer susceptibility gene 1 (BRCA1), beta-tubulin III (TUBB3), and microtubule-associated protein tau (MAPT)., Conclusions: Melittin had a synergistic effect on the cytotoxicity of chemotherapeutic agents. The possible mechanisms might be associated with down-regulating chemotherapeutic agent-associated genes.

This study was aimed to investigate the distribution of compact bone mesenchymal stem cells(MSC) marked with lentiviral plasmid pGC FU-RFP-LV in lung tissue and bone marrow of mouse. The MSC were infected by lentivirus with infection efficiency 78%, the infected MSC were injected into BALB/c mice via tail veins in concentration of 1×10(6) /mouse. The mice were randomly divided into 4 group according to 4 time points as 1, 2, 5 and 7 days. The lung tissue and bone marrow were taken and made of frozen sections and smears respectively in order to observed the distributions of MSC. The results indicated that the lentiviral infected MSC displayed phenotypes and biological characteristics which conformed to MSC by immunophenotyping analysis and induction differentiation detection. After the MSC were infected with optimal viral titer MOI = 50, the cell growth no significantly changed; the fluorescent microscopy revealed that the distributions of MSC in bone marrow on day 1, 2, 5 and 7 were 0.50 ± 0.20, 0.67 ± 0.23, 0.53 ± 0.14, 0.33 ± 0.16; those in lung tissue were 0.55 ± 0.15, 0.47 ± 0.13, 0.29 ± 0.13, 0.26 ± 0.08. It is concluded that the distribution of MSC in lung tissue reaches a peak on day 1, while distribution of MSC in bone marrow reaches a peak on day 2. The distribution of mouse MSC relates with RFP gene expression and implantation of MSC in lung tissue and bone marrow.

The interactions between the concentrations of sulfur, iron and cadmium in the rhizosphere and their uptakes in rice (Oryza sativa L. ) were studied using paddy soil which was contaminated by acid mine drainage under five water-management treatments of 60%, 80%, 100% field moisture capacity (FMC), flooded throughout the entire rice growth period and flooded followed by keeping 80% FMC after heading-flowering period. The water managements had no significant influence on the Fe and Cd concentrations in rhizosphere soil in maturity stage, although the concentration of Cd slightly increased with the increase of soil moisture in the tillering stage. However, the uptake of Fe and Cd in rice was obviously related to water managements. The increase of soil moisture enhanced the uptake of Fe, but decreased the uptake of Cd in different organs of rice (roots, stems and leaves, grains) except for Cd uptake of the root in the 60% FMC treatment. However, aerobic treatment after heading-flowering period enhanced Cd uptake in rice in all treatments, but did not influence the uptake of Fe in rice. On the other hand, the increase of soil moisture reduced the concentrations of total sulfur and available sulfur in the rhizosphere soil except for the 60% FMC treatment, which corresponded with the reduction of Cd uptake in rice. And the aerobic treatment promoted Cd uptake in rice, which was also positively related to the increase of total sulfur and available sulfur in rhizosphere soil. Therefore, it was concluded that the uptake and speciation of sulfur in rhizosphere soil other than the change of Fe concentration induced by water management could play an important role in Cd uptake of rice.

Objective: To explore the behaviors of smokers as well as the tobacco consumption in Jiangxi province. Impact regarding the increases of tobacco retail price on the smoking behaviors among cigarette consumers was also studied. Data was provided for further development on measurements including legislation, taxing and increasing the retail price on tobacco., Methods: 805 residents above 15 year-olds were chosen through random clustered sampling, and face to face interviewed, in Shangrao and Yichun of Jiangxi province. A chart was drawn to show the relationship between the change of smoking behavior and the increase of sales price of tobacco., Results: The average rate of smoking was 27.08% (46.62% for males and 3.05% for females). 16.06% (35/218) of the smokers had ever tried to quit smoking but failed. The years of smoking ranged from 1 year to 50 years, with 96.33% of the smokers purchased cigarettes on their own. Price of the cigarette ranged from 15 to 30 RMB per package, and smokers usually spent on average 192 RMB which accounted 13% of their monthly income, per month. According to the chart, if the cigarette price had a 50% increase, it would lead to 45% of the smokers reduce the number of cigarette consumption with another 5% of the smokers attempt to quit smoking. If cigarette price had an increase by 2 times, 50% of the smokers would attempt to quit smoking. So the chart could be used to estimate the percentage of smokers' behavior change according to the increase of tobacco's sales price., Conclusion: The economy burden of tobacco consumption among cigarette smokers was huge, suggesting that the Chinese smokers did need to change their smoking behavior. Chinese government should develop tobacco-related legislation and laws and set proper cigarette tax, hopefully this could reduce the number of smokers in a long run.

This study was aimed to construct, package and purify the recombinant lentivirus vector carrying the firefly luciferase gene (FLUC) and red fluorescent protein gene (RFP) and to transfect the recombinant lentivirus into HeLa cells, so as to observe the expression levels of these two genes. The FLUC and RFP genes were amplified by RT-PCR and inserted in the lentiviral expression vector (pLenti-Bi-cistronic) to construct the lentiviral vector pLenti-FLUC-RFP. The viral particles were generated by cotransfection of 293T cells with pLenti-FLUC-RFP and three packaging vectors, and the virus titer was determined by calculating the percentage of RFP positive cells. After transfection of pLenti-FLUC-RFP into HeLa cells, the expression of RFP was observed by fluorescent microscopy, and the activity of FLUC was determined by luciferase reporter gene assay kit. The results showed that the inserting orientation of the RFP and FLUC genes in the lentiviral vector pLenti-FLUC-RFP were verified by restriction analysis. Targeted RFP and FLUC sequences were confirmed by DNA sequencing. The final titer obtained was 1×10(7)TU/ml. The expressions of RFP and FLUC were observed in the transfected HeLa cells. It is concluded that the pLenti-III-FLUC-RFP recombinant lentivirus vector carrying RFP gene and FLUC gene with high viral titer is constructed and packaged successfully, and provides experimental basis for studying dynamic distribution of mesenchymal stem cells in vivo.

Mesenchymal stem cells (MSC) are the non-hematopoietic stem cells with a multi-differentiation potentials, which has a low immunogenicity and immune regulation ability. MSC immune regulation ability is particularly important, such as MSC can inhibit the activation and proliferation of T, B lymphocytes, NK cells and dendritic cells (DC). Meanwhile, MSC is able to reconstruct the human hematopoietic microenvironment, improving the successful rate of hematopoietic stem cell transplantation. Graft versus host disease (GVHD) is the main factor causing hematopoietic stem cell transplantation-related mortality. Based on the above mentioned properties, MSCs are used to treat autoimmune diseases and GVHD, recently. Therefore, deep exploration of the cellular immune mechanisms of MSC to treat GVHD is particularly important. This review focuses on progress of research related to treatment of GVHD by MSC immune mechanisms and briefly summarizes the status of the clinical studies.

Aim: To investigate the chronic effect of palmitic acid (PA) on apoptosis of pancreatic islet beta-cells and the possible mechanism., Methods: Insulinoma cell line (MIN6 cells) were used in this study. After being incubated in PA (0.1 - 1.6 mml/L) for 24 and 48 hours, MTT method was used to evaluate the livability. After being incubated for 48 h, Hoechst-PI and Annexin-V-FTTC/PI FACS were used to estimate the apoptosis in each group, Western-blotting assay was used to estimate the protein level of p-Akt, Akt, Bax and Bcl-2., Results: Chronic PA dose-dependently (1) decreased the availability and increased the apoptosis of MIN6 cells; (2) decreased the phosphorylation of Akt and Bcl-2, but had no significant effects on Akt and Bax., Conclusion: Chronic PA dose-dependently induced apoptosis of MIN6 cells, and this effect was possibly regulated by Akt/Bcl-2.

By the methods of emergy, this paper studied the input and output, working efficiency, and environmental loading of the agro-ecolomic system in Shanxi Province in 2005. The results showed that in 2005, the agro-ecolomic system in Shanxi still stayed in the period of traditional agriculture, which mainly depended on manpower and environmental resources. The emergy investment ratio (EIR) was 1.07, emergy yield ratio (EYR) was 0.99, and environmental loading ratio (ELR) was 6.55. In the structural adjustment of agriculture, stockbreeding had made great strides forward, but grain crops other than rice and wheat, vegetables, and fruits still had smaller emergy yield and were far from becoming dominant industry. The efficiency of the agro-ecolomic system was lower, and its environmental loading press was bigger. For the future, the surplus labors in agriculture in Shanxi should be shifted continually to other industries, and the high quality emergy such as agricultural science and technology should be increased to improve the use efficiency of environmental resources and the input and output of the system emergy.

Objective: to establish an ELISA method for detecting the activity of reverse transcriptase., Methods: Oligo (dT) 15 was immobilized via its 5'-terminal phosphate to Covalink-NH microtiter plates,The biotin-dUTP was incorporated by reverse transcriptase. The products were detected and quantified using a colorimetric streptavidin-alkaline phosphatase reporter system., Results: We established an ELISA RT assay method and tested the inhibition activity of PFA and NVP respectively. Using this method we also studied the kinetic mechanism of AMV-RT and HIV-1 RT. At the same time, we evaluated the stability, repeatability, specificity and sensitivity of this ELISA method., Conclusion: This ELISA method has particular advantages, such as simplicity, rapidity, specificity and little pollution, and is suitable for screening and studying of specific inhibitors of HIV-1 reverse transcriptase and other RTs.

Objective: To evaluate the short-term safety and efficacy of paclitaxel-eluting stent (TAXUS stent, Boston Scientific) in the treatment of coronary heart disease (CHD) due to coronary arteriosclerosis., Methods: From July 2003 to November 2004, 300 consecutive patients with CHD due to coronary arteriosclerosis were admitted for selective percutaneous coronary intervention (PCI) and paclitaxel-eluting stent implantation in the coronary arteries. The immediate effects after PCI and follow-up results were investigated., Results: Altogether 350 lesions were treated and 355 paclitaxel-eluting stents implanted in the 300 cases. Of these lesions, 248 (70.9%) was complicated lesions of B2 type or worse, 94 (26.5%) small-caliber stents (2.50-2.75 mm) and 130 (36.6%) long stents (>20 mm) were implanted, without occurrence of severe intra-operative complications. Follow-up study of 250 cases (83.3%) lasting for 1 to 15 months was conducted, and chest pain was reported in 8 cases, 2 of which underwent coronary artery angiography and no in-stent restenosis was found. One patient developed myocardial infarction 5 months after PCI, and 2 died for non-cardiogenic factors., Conclusion: Paclitaxel-eluting stent implantation in patients undergoing PCI is safe approach with good short-term efficacy.

Objective: To investigate the antibacterial effects of zirconium phosphate gauze loaded with silver on rat burn wounds seeded with commonly seen bacteria., Methods: Wistar rats were employed in the study and were scalded and infected. The minimum inhibition concentration (MIC) and minimum bactericidal concentration (MBC) of zirconium phosphate loaded with silver were determined by double dilution in tubes. The effect on wound healing and the subeschar bacterial count of the rat burn wounds were observed after the wounds had been covered by gauze loaded with zirconium phosphate and silver, and also with the gauze which has been rinsed for 20 times., Results: The MIC of silver loaded zirconium phosphate on Staphylococcus aureus, Pseudomonas aeruginosa and E. coli were 8, 8 and 16 mg/L, respectively, while the MBC were 16, 8 and 32 mg/L, respectively. The subeschar bacterial count in the burn wounds with the gauze with silver loaded zirconium phosphate was ten times lower than that in those which were treated with gauze with SD-Ag and 100 times lower than that with ordinary gauze. But there was no difference in the bacterial count between the wounds which were treated with fresh gauze with silver loaded zirconium phosphate and that with the gauze which has been rinsed for 20 times (P > 0.05). Furthermore, wound healing seemed to be better with the gauze with silver loaded zirconium phosphate when compared with those by the other two kinds of gauze., Conclusion: The silver loaded zirconium phosphate was found to be bacteriocidal against bacteria commonly seen in the burn wounds.

Objective: To explore the role of indirect antigen presentation pathway on the immunogenecity of epidermal cells., Methods: Human epidermal cells (HEC), allogeneic human peripheral blood lymphocytes (PBL) and mononuclear cells (PBM, including monocytes) were isolated and cultured in vitro. HECs were transfected by human-originated CTLA4Ig-adenovirus vector. The CTLA4Ig expression was observed. Allogeneic PBLs or PBMs were added to the transfected and non-transfected HECs with simple cultured PBLs and PBMs as the control. The proliferation of PBL and PBM was determined by (3)H-TdR incooperation., Results: HECs could be successfully transfected by CTLA4Ig-adenovirus vector and expressed corresponding proteins. The non-transfected HECs could stimulate slight proliferation of allogeneic PBLs (P < 0.05) and stimulate remarkable proliferation of PBMs (including monocytes) (P < 0.05). The proliferation reaction of PBLs and PBMs decreased significantly (P < 0.05) after being stimulated by HEC which was modulated by CTLA4Ig genes., Conclusion: Indirect antigen presentation pathway might play important roles in the HEC immunogenicity which could be evidently inhibited by CTLA4Ig.

The present study was performed on anesthetized and paralyzed Wistar rats. Extracellular recordings were made from the lumbar enlargement of the spinal cord using carbon filament electrodes. NO donor sodium nitroprusside (SNP) was locally microdialyzed to the spinal cord, and effects of NO on spontaneous response and the responses induced by mechanical stimulation of the hind-foot were observed. After dialyzing for 10~20 min, SNP at a concentration of 1 micromol/L increased the induced responses to innocuous mechanical stimulation and decreased those to noxoius mechanical stimulation. The induced responses to both innocuous and noxious mechanical stimulations were all decreased after dialyzing the same dose of SNP for 20~30 min. The decrease was shown within 7~15 min dialysis when SNP was used at a concentration of 20 micromol/L. SNP at both concentrations of 1 and 20 micromol/L increased spontaneous spikes of the recorded spinal units. These effects were shown preferentially in deep units. The data suggest that in the deeper neurons of the spinal cord NO of different concentrations has different effects on transmission of nociceptive and nonnociceptive signals induced by mechanical stimulation, and No is involved in the antinociception in spinal neurons and facilitates their spontaneous activity.

Time-dependent inhibition is one of the means to study the interactions between peripheral inputs. The present study was performed on anesthetized and paralyzed Wistar rats using the technique of conditioning-testing stimulation. Electric stimulation (1.5 3 folds of the threshold intensity) was given to pelvic and pudendal nerves. Extracellular recordings were made from convergent neurons at L(6)-S(1) segments of the spinal dorsal horn. Stimulus intervals between conditioning and testing stimulation were measured when a half of the testing responses were inhibited by conditioning responses or the inhibition just began to occur. The time-dependent inhibition was seen in neurons situated deeper than 300 m beneath the dorsal surface of the spinal cord, and not in more superficial neurons. The inhibition intervals were in the range of 1 360 ms and became longer when conditioning stimulation was given to the pelvic nerve. The inhibition intervals were 1 3 ms in superficial neurons (<300 micrometer) and no apparent time-dependent inhibition occurred. The inhibition in deeper neurons was partially reduced by cold block conducted at segments C(5-6) and the blockage was more significant when conditioning stimulation was applied to the pelvic nerve. These findings suggest that the inputs from the pelvic and pudendal nerves may converge on single neurons at deeper lumbosacral dorsal horn and the pudendal nerve induced responses are more likely to be inhibited in these neurons, which may be further strengthened by superspinal structures.