Objective To define the effect and mechanism of hyperkalemic solution on atrial natriuretic peptide (ANP) secretion in rabbits. Methods Eighteen rabbits were selected and the chest was opened under anes-thetization to remove the heart. The left atrium was isolated and fixed in the atrial perfusion system with proper electric stimulation for beating. The following experiments were carried out on beating rabbit atria: ①The atrium was perfused for 60 min to stabilize parameters of ANP secretion and atrial dynamics. The control period (12 min as an experimental cycle) was followed by an infusion of hyperkalemic solution (K+ concentration of hyperkalemic solution was 5.64 mmol/L and the osmolarity of hyperkalemic solution was unchanged) for three cycles, then normal K+ cancentration was recovered for two cycles;②The control period was followed by an infusion of L type Ca2+ channel blocker nifedipine (1.0 μmol/L) for three cycles;③L type Ca2+ channel inhibitor nifedipine (1.0 μmol/L) was infused for 36 rain prior (three cycles) to infusion of hyperkalemic solution. Atrial stroke volume was determined and the ANP secretion was measured by radioimmtmoaasay. Results (1)Hyperkalemic solution increased atrial ANP secretion (P<0.01) and reduced the atrial stroke volume,hut the difference was not statistically significant as compared with that of the control cycle(P>0.05). The recovery trend was to the normal level of ANP secretion and atrial stroke volume was to become normal gradually when solution level recovered to normal ,which was not significantly different from that of the control cycle (P>0.05) ;②Nifedipine (1.0 μmol/L) also increased the atrial ANP secretion (P<0.01 or P <0.05) while decreasing atrial stroke volume (P<0.01 or P < 0.05 ) ; ③Nifodipine (1.0μmol/L) completely blocked the effect of hyperkalemic solution so to increase the ANP secretion (P <0.01 ). Conclusion Hyperkalemic solution significantly increases atrial ANP secretion via extracellular high K+ competitive inhibition of extracellular Ca2+ inflow in beating rabbit atria.

Adult ; Coal Mining ; Dust ; analysis ; Humans ; Incidence ; Male ; Middle Aged ; Occupational Exposure ; Pneumoconiosis ; epidemiology ; Workplace

AIM: To evaluate the mobilization of endothelial progenitor cells (EPCs) in mice peripheral blood during hindlimb ischemia alone or in combination with granulocyte colony stimulating factor (G-CSF). METHODS: Hindlimb ischemia was established in mice by surgical excision of both femoral arteries. Fluorescence-activated cell sorting (FACS) was used to detect the expression of cell-surface CD34 and vascular endothelial growth factor recepter-2 (VEGFR2) antigens. The ratio of double-positive cells for CD34 and VEGFR2 was regarded as the level of EPCs in peripheral blood. In G-CSF administration in combination with hindlimb ischemia group, the percentage of double-positive cells was also detected. RESULTS: As compared with control group, hindlimb ischemia increased the percentage of EPCs in mice peripheral blood. The hindlimb ischemia combined with G-CSF administration significantly enhanced the percentage of EPCs. CONCLUSION: Ischemia increases the number of EPC in peripheral blood. It may induce the migration of EPC from barrow to peripheral blood. By mobilizing barrow, G-CSF enhances this effect.

ObjectiveTo observe testis tissue changes of experimental cryptorchidism after orchiopexy in various-day-rats.MethodsSeventy-two Sprague-Dawley(SD) male rats were divided into 3 groups randomly and made artificial cryptorchidism:unilateral cryptorchidism group(n=24),bilateral cryptorchidism group(n=24)and sham operation group(n=24)at age 21-day-old.Intra-abdominal testicle was resetting in 2 weeks,at age 40 days and 60 days,the rats were sacrificed for detection tubular fertility index(TFI) and mean tubular diametar(MTD) with hematoxylin-eosine staining and germ cell apoptosis by terminal deoxynucleotidyl transferase mediated d-UTP nick end labeling(TUNEL) assay.ResultsThere were significant differences of MTD,TFI and apoptosis index(AI) between cryptorchidism and scrotal testes(P0.05).The AI of cryptorchidism testes of unilateral cryptorchidism group were significantly lower than that of bilateral cryptorchidism group in 40 days(P0.05).ConclusionsAI of artificial resetting testis is increased and contralateral descended testes in unila-teral cryptorchidism have various damage.It is to lighten that pathological damage of testes of cryptorchidism with prolongation of reset time.

Objective To analyze the epidemiological characteristics of Mycobacterium tuberculosis by enterbaeterial repetitive intergenic consensus-polymerase chain reaction(ERIC-PCR)DNA fingerprint. Methods Mycobacterium tuberculosis positive sputum samples between September 2003 to May 2006 were collected and cultured.Chromosomal DNA were extracted and ERIC-PCR DNA fingerprinting was analyzed by software,such as RAPD PHYLIP and Treeview.Results A total of 42 different fingerprints were detected.Phylogenetic analysis showed that they could be classified into three clusters,the clustering rate was 72.6%.The characteristics of ERIC-PCR fingerprint patterns were related to age,drug resistance,and type of resistance.Conclusions ERIC-PCR DNA fingerprinting technique used in this study is good for epidemiological studies with its strong discrimination,simplicity and rapidness.A high level of recent transmission is found in our city.

N-type voltage-gated calcium (Ca²⁺) channels (N-type VGCC, Ca_V2.2) mediate Ca²⁺ influx in response to action potential at the presynaptic terminal, and play an important role in synaptogenesis, neurotransmitter release and nociceptive signal transduction. It is a new target for the development of drugs for the treatment of neuralgia (chronic pain) and other major diseases. Due to the difficulty of calcium channel expression in vitro and the detection of channel current, there is a great lack of new drug screening models. In this study, we established and optimized the electrophysiological drug screening model using Xenopus laevis oocytes for the recombinant expression of Ca_V2.2 in vitro (this study were reviewed and approved by the Ethics Committee of Guangxi University, approval number: GXU-2023-0249). Firstly, the linear plasmids encoding cDNA of major subunit α1B and auxiliary subunits α2δ1 and β3 of rat Ca_V2.2 were used as templates for in vitro transcription to generate their related mRNA (cRNA), after which three kinds of cRNA were injected into Xenopus laevis oocytes at the mass ratio of 2∶1∶1 for expression. The two-electrode voltage clamp (TEVC) technique was used to detect the inward current produced by Ca_V2.2. At the same time, the expression conditions of Ca_V2.2 were optimized, and its gating function was characterized from the aspects of channel activation and inactivation. The results showed that 3-5 days after cRNA microinjection, stable Ca_V2.2-mediated barium ion (Ba²⁺) currents were successfully detected. The interference of endogenous potassium channels and Ca²⁺-activated chloride channels can be eliminated by tetraethylammonium hydroxide (TEAOH) and 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis (BAPTA-AM) treatment. The maximum potential for Ca_V2.2 activation is 0 mV, and the current reverses to be outward when the membrane potential is greater than +50 mV. By fitting the steady-state activation and inactivation curves, the half-maximal activation potential and half-maximal inactivation potential of Ca_V2.2 are identified as -15.9 and -60.2 mV. In this study, a stable Ca_V2.2 expression system was established based on Xenopus laevis oocytes. The in vitro expression system can provide a new way for the screening of Ca_V2.2 active compounds or lead drugs.

Objective To understand the pathogen detection of hospitalized patients before antimicrobial therapy in a hospital through implementation of comprehensive intervention measures,and provide reference basis for the de-velopment of targeted measures.Methods Hospitalized patients who received therapeutic antimicrobial agents in this hospital were selected as the research subjects.Patients who were hospitalized from January to May 2022 were selected as the pre-intervention group,comprehensive intervention measures were taken from June to October 2022,and those who were hospitalized from November 2022 to March 2023 were selected as the post-intervention group.The pathogen detection rate before antimicrobial therapy,sterile specimen detection rate,antimicrobial use rate,de-tection rate of key multidrug-resistant organisms of patients before and after the intervention were analyzed.Results Compared to before intervention,the proportion of pathogen detection rate before antimicrobial therapy(62.09％vs 74.04％),detection rate of healthcare-associated infection diagnosis-related pathogens(62.82％vs 92.73％),and sterile specimen detection rate(35.17％vs 41.06％)of hospitalized patients after intervention all increased signifi-cantly,with statistically significant differences(all P＜0.05).After intervention,pathogen detection rate before the combination use of key antimicrobial agents was not statistically different from before intervention(93.33％vs 90.48％,P＞0.05),while antimicrobial use rate was lower than before intervention(39.93％vs 44.95％,P＜0.05).There was no statistically significant difference in the detection rate of key multidrug-resistant organisms be-fore and after intervention(all P＞0.05).Conclusion Adopting scientific and rational intervention measures can improve the pathogen detection rate,provide a reference basis for the rational use of antimicrobial agents.There was no significant improvement in the pathogen detection rate before the combination use of key antimicrobial agents and the detection rate of key multidrug-resistant organisms,indicating that relevant measures still need to be further optimized.

OBJECTIVETo study effects of different interval year on Panax notoginseng plant soils middle and micro element content.

METHODThe dynamic change of Ca, Mg, Mn, Cu, Zn, B from Mabai, Matang, Gumu and Panlong were determined under different planting patterns (new soil, interval 5 years soil and continuous cropping soil).

RESULTAll the micro elements (except Ca, Mg) of interval 5 years soil and continuous cropping soil were significantly higher than those of new soil. All the middle and micro elements (except B) of interval 5 years soil were significantly higher than those of the continuous cropping soil. Planting patterns had remarkable influence on the content of Mn, Cu, B, but not Zn Ca, Mg. Cu, Ca under the 3 planting patterns, and Zn under the continuous cropping pattern did not show significant quarter changes. B content increased with the elongation of implantation time. Zn in new soil and interval 5 years also increased with prolonging of planted time. Mg, Mn and Cu content reached to peak value on April next year, and reached to minimum on the end of this experiment. Compared with new soil, the proportion of Mn, Cu in total elements increased by 29%, 114%, Mg, B decreased by 18%, 38%, Zn and Ca changed slightly of interval 5 years soils; In continuous cropping soil, Mn, Cu and B increased by 50%, 120%, 22%, respectively, but Zn, Ca, Mg had no significant change.

CONCLUSIONContinuous cropping pattern could not induce the deficient of soil middle and micro elements, and thereafter might not result in continuous cropping obstacles. But the imbalance proportional of soil middle and micro elements in P. notoginseng plant soils may be one of the main reasons for continuous cropping obstacles.

China ; Kinetics ; Panax notoginseng ; growth & development ; Soil ; chemistry ; Time Factors ; Trace Elements ; chemistry

OBJECTIVETo study effects of different interval year on Panax notoginseng plant soils macro element content.

METHODThe dynamic change of total N, P, K and available N, P, K in soil from Mabai, Matang, Gumu and Panlong was determined under different planting patterns (new soil, interval 5 years soil and continuous cropping soil).

RESULTContents order of soil total N, P and available N, P were interval 5 years soil > continuous cropping soil > new soil. No significant quarter change on soil total N was found, but the other three showed inverted "v" curve, and the peak value appeared on April 2010. Content of soil total K did not change significantly, but the available K content order was new soil > continuous cropping soil > interval 5 years soil, the quarter change was similar as soil available N or P. The soil total N, P, K and available N, P, K were different of the 4 monitoring sites under the 3 interval planting modes. There was a significant correlation between soil total P and available P under all these 3 interval planting modes, but N and K. The propitiation of N-P-K of new soil, interval 5 years soil and continuous cropping soil were 1: 0.4: 2.4, 1: 0.4:1.4, 1:0. 4:2.0, respectively.

CONCLUSIONContinuous cropping pattern induce the accumulation of P, but deficient of K. The imbalance proportion of N, P and K was one of the incentives of continuous cropping induced obstacles. Strengthen the research of optimum proportion of soil N, P and K, and then eliminate continuous cropping obstacles by means of formulated fertilization is the future research direction.

Agriculture ; methods ; Breeding ; China ; Drugs, Chinese Herbal ; analysis ; Fertilizers ; analysis ; Nitrogen ; analysis ; metabolism ; Panax notoginseng ; chemistry ; growth & development ; metabolism ; Phosphorus ; analysis ; metabolism ; Potassium ; analysis ; metabolism ; Quality Control ; Soil ; chemistry

Objective To analyze the causes associated with the failure of dental implant restoration. Methods The patients who received dental implant restoration from January 2001 to December 2008 in Center of Dental Implant, School of Stomatology, Shandong University were reviewed and analyzed.The cases with implant loosening, broken or removed were considered failure. Results There were a total of 38 failure implants in 32 patients found in this group of patients. Of those, 33 implants loosened (17 cases before restoration and 16 cases after restoration), two were broken, two retention screws broken and one implant perforated on buccal side. The causes of failure included doctor-related factors in 19 cases, patientrelated factors in 9 cases, implant-related factors in two cases and two uncertainties. Conclusions Doctorrelated factor is the main cause of dental implant failure, followed by patient-related factor and implantrelated factor.