A high resolution reaction microscope with universal two-region time-focusing method

This paper presents a novel reaction microscope designed for ion-atom collision investigations, established at the Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China. Its time-of-flight (TOF) spectrometer employs an innovative flight-time focusing method consisting of two acceleration regions, providing optimal time focusing conditions for charged fragments with diverse initial velocities. The TOF spectrometer's axis intentionally tilts by 12° relative to the ion beam direction, preventing potential obstructions from the TOF grid electrodes. The introduced focusing method allows for a flexible time-focusing TOF spectrometer design without restricting the length ratio of the two regions. In addition, this configuration in our case significantly suppresses noise on the recoil ion detector produced by residual gas in the ion beam trajectory, which is a considerable challenge in longitudinal spectrometers. In a test experiment on the single electron capture reaction involving 62.5 keV/u He2+ ions and a helium atomic beam, the recoil longitudinal momentum resolution achieved 0.068 atomic units. This novel configuration and successful test run show excellent precision for ion-atom collision studies.

[Clinical research of multisystem inflammatory syndrome in children]

Objective: To analyze the clinical characteristics of children with multisystem inflammatory syndrome (MIS-C) associated with SARS-CoV-2 in China, and to improve the understanding of MIS-C among pediatricians. Methods: Case series study.Collect the clinical characteristics, auxiliary examinations, treatment decisions, and prognosis of 64 patients with MIS-C from 9 hospitals in China from December 2022 to June 2023. Results: Among the 64 MIS-C patients, 36 were boys and 28 were girls, with an onset age being 2.8 (0.3, 14.0) years. All patients suffered from fever, elevated inflammatory indicators, and multiple system involvement. Forty-three patients (67%) were involved in more than 3 systems simultaneously, including skin mucosa 60 cases (94%), blood system 52 cases (89%), circulatory system 54 cases (84%), digestive system 48 cases (75%), and nervous system 24 cases (37%). Common mucocutaneous lesions included rash 54 cases (84%) and conjunctival congestion and (or) lip flushing 45 cases (70%). Hematological abnormalities consisted of coagulation dysfunction 48 cases (75%), thrombocytopenia 9 cases (14%), and lymphopenia 8 cases (13%). Cardiovascular lesions mainly affected cardiac function, of which 11 patients (17%) were accompanied by hypotension or shock, and 7 patients (12%) had coronary artery dilatation.Thirty-six patients (56%) had gastrointestinal symptoms, 23 patients (36%) had neurological symptoms. Forty-five patients (70%) received the initial treatment of intravenous immunoglobulin in combination with glucocorticoids, 5 patients (8%) received the methylprednisolone pulse therapy and 2 patients (3%) treated with biological agents, 7 patients with coronary artery dilation all returned to normal within 6 months. Conclusions: MIS-C patients are mainly characterized by fever, high inflammatory response, and multiple organ damage. The preferred initial treatment is intravenous immunoglobulin combined with glucocorticoids. All patients have a good prognosis.

[Studies of the norm of Karitane Parenting Confidence Scale(KPCS)among parents of infants in urban areas of China]

Objective: To establish the norm of the Chinese version of Karitane Parenting Confidence Scale (KPCS) in urban areas of China. Methods: From August to December 2017, the parents of 2 216 children (<36 months old) were selected from 15 cities (Beijing, Lianyungang, Hangzhou, Chengdu, Xi'an, Guangzhou, Changsha, Jinan, Guiyang, Ningbo, Dalian, Qinhuangdao, Maanshan, Chongqing and Wuhan) in 14 provinces by stratified random sampling. The general demographic characteristics and parents' parenting confidence were collected by a self-made questionnaire and KPCS Chinese version. The percentile norm was established. P₃, P₁₀ and P₂₅ were used as the criteria to define the degree of lack of parenting confidence. Results: The age of mothers was (30.67±4.29). The age of the father was (32.50±4.99) years old. There were 726 (32.76%), 759 (34.25%) and 731 (32.99%) infants in 6-12, 12-23 and 24-35 months old groups. The total scores of P₅₀, P₂₅, P₁₀ and P₃ of KPCS (Chinese version) of infant parents in urban areas in China were 41, 38, 33, and 29 respectively. When the scores of parents were 34-37, 30-33, and ≤ 29, they were judged as mild, moderate, and severe lack of parenting confidence. There was no significant difference in the Chinese version of KPCS between parents of different age groups and parents of different gender (χ²=3.53, P=0.171; χ²=1.41, P=0.236). Each factor score≤P₃ is defined as the boundary score, and the corresponding boundary scores of "parenting" "support" and "competence" were 13, 9, and 5 respectively. Conclusion: The Chinese version of KPCS can be used to assess the parenting confidence of infants in urban areas of China. It can used as one of the bases for scientific and objective evaluation of the parenting status of families.

Correlation between endometrial receptivity with expressions of IL-1 and VEGF in rats with polycystic ovary syndrome

OBJECTIVE

To investigate the correlation between endometrial receptivity with expressions of interleukin-1 (IL-1) and vascular endothelial growth factor (VEGF) in rats with polycystic ovary syndrome (PCOS).

MATERIALS AND METHODS

A total of 24 female Sprague-Dawley (SD) 21 days old were randomly divided into control group (n=12) and PCOS group (n=12). Rats in the control group were normally raised, and PCOS model was established in rats of the PCOS group. All the rats were sacrificed when they grew to 80 days old. Immunohistochemistry was applied to detect the expressions of IL-1 and VEGF. Western blotting was performed to measure the relative expressions of IL-1 and VEGF proteins. Quantitative Polymerase Chain Reaction (qPCR) was utilized to determine the relative messenger ribonucleic acid (mRNA) expressions of IL-1 and VEGF. Data related to endometrial receptivity were detected.

RESULTS

The expression levels of IL-1 and VEGF in the PCOS group declined markedly compared with those in the control group, and the differences were statistically significant (p<0.05). PCOS group had notably lower protein expressions of IL-1 and VEGF than the control group, with statistically significant differences (p<0.05). The mRNA expressions of IL-1 and VEGF in PCOS group were significantly lower than those in the control group, displaying statistically significant differences (p<0.05). Compared with that in the control group, the endometrial receptivity of rats in the PCOS group was reduced evidently, and the difference was statistically significant (p<0.05). Both IL-1 and VEGF had positive correlations with the endometrial receptivity.

CONCLUSIONS

Both IL-1 and VEGF are positively correlated with the endometrial receptivity in the case of PCOS, which can serve as therapeutic targets for PCOS and improve endometrial receptivity in the future.

[Performance of high-risk HPV typing test in early diagnosis of cervical cancer]

Objective: To evaluate the performance of High-risk HPV typing detection in cervical cancer screening. Methods: A total of 3 231 women were recruited as the subjects of cervical cancer screening from Jiyuan city of Henan provinces from June to July 2017. All women underwent HPV DNA test. The women with cytological examination ≥ASCUS or cytological examination negative and HPV 16/18 positive underwent colposcopy biopsy and pathological examination. Pathological diagnosis was used as the gold standard. Sensitivity, specificity, positive predictive value (PPV), negative predictive value(NPV) as well as corresponding 95% confidence interval (CI) of HR-HPV and HPV 16/18 were calculated. Results: The mean age of 3 231 subjects selected in this study was 46.84±10.00 (21-64) years old. 524 subjects had the positive results of HR-HPV, including 91 of HPV16 and 15 of HPV18. Pathological test result CIN2+ was the gold standard. The sensitivity and specificity of HR-HPV for cervical precancer lesions screening were 93.75 (95%CI: 79.85-98.27) and 84.56% (95%CI: 83.26-85.77), respectively. To compared with HR-HPV, HPV16/18 had low sensitivity (65.63%, 95%CI: 48.31-79.59)and higher specificity (97.44%, 95%CI: 96.83-97.93). After age stratification by age 30 and 45, the sensitivity of HPV 16/18 was same with HR-HPV (100%, 95%CI: 34.24-100.00), the specificity of HPV 16/18 was higher than HR-HPV (98.71%, 95%CI: 96.27-99.56 vs 84.48%, 95%CI: 79.27-88.58) in<30 age group.The sensitivity of HR-HPVin 30-45 and ≥45 age group were higher than HPV16/18 (85.71%, 95%CI: 48.69-97.43 vs 71.43%, 95%CI: 35.89-91.78, 95.65%, 95%CI: 79.01-99.23 vs 60.87%, 95%CI: 40.79-77.84), but the specificity werelower than HPV16/18 (86.89%, 95%CI: 84.58-88.90 vs 98.51%, 95%CI: 97.51-99.11、83.49%, 95%CI: 81.81-85.04 vs 96.80%, 95%CI: 95.94-97.48). Conclusions: HR-HPV detection has relatively high sensitivity and specificity in cervical cancer screening. For >30 years old women, HR-HPV is more recommended in cervical cancer screening. Therefore, HR-HPV detection is an effective method for cervical cancer screening.

[Evaluation the triage performance of p16/Ki-67 dual staining for HR-HPV positive women]

Objective: This study aimed to evaluate the clinical performance of p16/Ki-67 dual staining for triage high risk HPV (HR-HPV) infected women. Method: Target objects were women who infected HR-HPV and received colposcopy examination between April and December of 2016 at the Second Affiliated Hospital of Zhengzhou University. Gynecologists collected the cervical exfoliated cells from eligible women for p16/Ki-67 dual staining, LBC testing and HPV DNA testing. Histology diagnosis were used as gold standard. Sensitivities, specificities, positive predictive values (PPVs), negative predictive values (NPVs) of p16/Ki-67 dual staining, LBC testing and HPV16/18 testing for triage of HR-HPV positive population were calculated and compared. Results: A total of 295 HR-HPV infected women were selected, and the mean age was (44.29±11.48) years old. Positive rates of p16/Ki-67 dual staining, HPV16/18 testing and LBC testing were 70.17% (207), 56.95% (168) and 85.76% (253), respectively. When CIN2+as the endpoint, among the three triage methods, sensitivity of p16/Ki-67 dual staining was 90.00% (95%CI: 85.06%-93.43%), higher than the value of HPV 16/18 testing, but lower than the value of LBC testing. Specificity, PPV and NPV of p16/Ki-67 dual staining were the highest [71.58% (95%CI: 61.81%-79.67%), 86.96% (95%CI:81.69%-90.88%) and 77.27% (95%CI: 67.49%-84.78%)]. When detection for CIN3+, sensitivity of p16/Ki-67 dual staining was 92.90% (95%CI: 87.74%-95.99%), lower than the value of LBC testing, but higher than the value of HPV16/18 testing. Specificity of p16/Ki-67 dual staining was 55.00% (95%CI: 46.74%-63.00%), lower than the value of HPV16/18 testing, but higher than the value of LBC testing. PPV of p16/Ki-67 dual staining was 69.57% (95%CI: 62.99%-75.43%), lower than the value of HPV 16/18 testing, but higher than the value of LBC testing. NPV of p16/Ki-67 dual staining was 87.50% (95%CI: 78.99%-92.87%), higher than value of HPV 16/18 testing, but lower than the value of LBC testing. Conclusion: p16/Ki-67 dual staining has better clinical effects than HPV 16/18 testing and LBC testing for triage women with HR-HPV infection.

[Practice of parenting and related factors on children aged 0-5 in the urban areas of China]

Objective: To characterize the relations between the practice of parenting and associated factors on children (0-5 years old) in urban areas of China, in order to provide evidence for promoting the early development of children and to provide positive guidance and service programs on parenting. Methods: A total of 4 515 parents from 15 cities (14 provinces) were surveyed with a self-administered questionnaire. Parenting and Family Adjustment Scales (PAFAS) was used, including parameters as: consistency and coercive parenting, positive encouragement, parent-child relationship and parental emotion adjustment, family relationship and parental teamwork aspects, etc. Both single factor analysis and multiple linear regression were used to examine the associations between parenting practice, individual, parental and family factors. Results: The mean score of PAFAS was 21.00 (15.00-28.00), associated with factors as children's age, only-child family, premature delivery, father's education level, confidence on parenting, problems regarding the parental mood, annual family income, family structure and behavior on seeking professional help, etc. Results showed that there were big differences on the practice of parenting in China and influenced by variety of factors. Conclusions: The general situation of parenting was well, in the urban areas of China. The practice of parenting was associated with a series of individual, parental and family factors. Programs on improving the parenting skills and promoting the early development of children, should be highlighted.

Downregulation of hsa_circ_0000285 serves as a prognostic biomarker for bladder cancer and is involved in cisplatin resistance

Bladder cancer remains a very challenging disease to treat with the high rates of recurrence and progression associated with current therapies. Although the association between bladder cancer pathology and circRNAs remains undetermined, circRNAs signatures may be useful as prognostic and predictive factors and clinical tools for assessing disease state, treatment response and outcome. This study investigates if these circRNAs can be used as biomarkers for bladder cancer diagnosis and predicting treatment response. Herein, qPCR measured the expression of hsa_circRNA_100783, hsa_circ_0000285 and hsa_circRNA_100782 in bladder cancer tissues. It was established that sa_circ_0000285, but not hsa_circRNA_100782 and hsa_circRNA_10078, are significantly reduced in bladder cancer tissues and serum compared to adjacent tissues and healthy controls. Moreover, hsa_circ_0000285 expression was lower in cisplatin-resistant bladder cancer patients than in those who were cisplatin-sensitive. Here, hsa_circ_0000285 was associated with tumor size (p<0.001), differentiation (p<0.001), lymph node metastasis (p=0.038), distant metastasis (p=0.004) and TNM stage (p=0.013). Further analysis showed that hsa_circ_0000285 would be an independent prognostic factor for bladder cancer patient outcome. In conclusion, our study indicates hsa_circ_0000285 may be a novel biomarker for bladder cancer because of its involvement in bladder cancer chemo-sensitivity.

[A retrospective clinical study of sixty-three cases with persistent inflammation immunosuppression and catabolism syndrome]

Objective: To study the clinical characteristics and prognosis of patients with persistent inflammation immunosuppression and catabolism syndrome (PICS) in ICU. Methods: A total of 126 patients admitted to ICU (ICU stay of more than 10 days, age≥18 years) between January 2014 to December 2014 were retrospectively studied.Data were collected from electronic medical records including demographics, underlying disease, Acute Physiology and Chronic Health Evaluation Ⅱ (APACHEⅡ) score, Sequential Organ Failure Assessment (SOFA) score, laboratory parameters, ICU acquired infections and clinical outcome. Results: The overall incidence of PICS in ICU patients (ICU stay of more than 10 days) was 50.0%(63/126). There were no significant differences in baseline data such as gender, age, APACHEⅡscore, SOFA score and underlying diseases between the two groups(all P>0.05). Compared with the non-PICS group, there were more patients with gastrointestinal perforation in the PICS group (P=0.042), however, the medical or surgical admission did not differ between the two groups(P>0.05). During the stay in ICU, the PICS group showed a higher risk of developing acquired infections compared with the non-PICS group[PICS 63.5%(40/63) vs non-PICS 23.8%(15/63); P<0.001]. The infections were more caused by Candida in the PICS group than the non-PICS group [PICS 22.4%(11/49) vs non-PICS 2/17; P=0.003]. Moreover, the PICS group experienced longer stay in ICU[PICS(31.6±28.8) days vs non-PICS (20.4±11.3) days; P=0.0046] and higher ICU mortality [PICS 28.6%(18/63) vs non-PICS 6.3%(4/63), P=0.001]. Conclusion: PICS is a common manifestation of patients who stay in ICU more than 10 days, which is associated with high risk of ICU acquired infections, prolonged length of stay and high mortality.

Sensitive and rapid detection of Pectobacterium atrosepticum by targeting the gyrB gene using a real-time loop-mediated isothermal amplification assay

This study reports the development of a real-time, loop-mediated isothermal amplification (RealAmp) assay for the detection of Pectobacterium atrosepticum (P. atrosepticum). A phylogenetic tree was constructed based on the gyrB gene of P. atrosepticum and related species. Pectobacterium atrosepticum from different sources can be clustered in the same branch with 100% support rate. The RealAmp primers targeting the gyrB gene of P. atrosepticum worked most efficiently at 61·0°C. Compared with 55 related bacterial strains, the eight P. atrosepticum strains displayed positive reaction in the RealAmp assay. The melting temperature (Tm) of P. atrosepticum amplified products was about 85·0°C. The detection limit of the RealAmp assay for the detection of P. atrosepticum in pure culture was approx. 3 CFU reaction(-1) . The detection limit of the RealAmp assay for the detection of P. atrosepticum in artificially contaminated samples was 22 CFU reaction(-1) . The detection rate of the RealAmp assay for the detection of potato tubers was 28·5-32·0% higher than that of the conventional PCR. In summary, a specific, sensitive and rapid RealAmp assay based on the gyrB gene of P. atrosepticum, which can be easily performed and real-time monitored, was established.

SIGNIFICANCE AND IMPACT OF THE STUDY

Potato blackleg caused by Pectobacterium atrosepticum (P. atrosepticum) which is mainly transmitted through the seed potato leads to the decline in potato production. To reduce yield loss, rapid detection of P. atrosepticum in seed potato remains essential. Based on the gyrB gene of P. atrosepticum, species-specific primers were designed. A real-time, loop-mediated isothermal amplification (RealAmp) assay was established for the detection of P. atrosepticum. The RealAmp assay is a specific, rapid and sensitive method for P. atrosepticum detection. Therefore, it provides an effective diagnosis of potato blackleg in both the growing and stored potato.

Effect of miRNA-203 on cervical cancer cells and its underlying mechanism

miRNA-203 is involved in the development and progression of various types of cancer. However, its role in cervical cancer remains unclear. The aim of this study was to investigate the effect of miRNA-203 on the proliferation and migration of HeLa cervical cancer cells, as well as survivin expression in these cells. A miRNA-203 primer probe was designed according to a sequence obtained from NCBI. The expression of miRNA-203 in cervical epithelial cells and cervical cancer cells was detected by quantitative reverse transcriptase-polymerase chain reaction. The miRNA-203 expression pattern was compared between these two cell lines. The cervical cancer cells were transfected with miRNA-203 mimic or inhibitor to determine their effects on proliferation and migration. The expression of the miRNA-203 target protein (survivin) was analyzed by western blot. Cervical cancer cells showed reduced miRNA-203 expression compared to cervical epithelial cells. Transfection of miRNA-203 mimic upregulated the expression of miRNA-203, suppressed cell proliferation and migration, and downregulated survivin expression (P < 0.05). However, downregulation of miRNA-203 expression did not affect proliferation, migration, and survivin expression in cervical cancer cells (P > 0.05). In conclusion, upregulation of miRNA-203 in cervical cancer cells inhibits the proliferative and migratory capacities of these cells by downregulating the expression of survivin.

Antimicrobial activity of recombinant mature bovine neutrophil β-defensin 4 on mycobacterial infection

BACKGROUND

Previous studies have shown that human cathelicidin and defensins have effective antimicrobial activity against Mycobacterium spp.

OBJECTIVE

To investigate the antimycobacterial effect of mature bovine neutrophil β-defensin (mBNBD) 4 against Mycobacterium spp. infection for the first time.

DESIGN

mBNBD4 protein was expressed in Pichia pastoris GS115. We used immunofluorescent assay to detect whether the recombinant mBNBD4 had entered the macrophages. The antimycobacterial activity of mBNBD4 was tested through colony-forming unit (cfu) assay. Morphological changes in the cell wall of M. bovis treated with mBNBD4 were observed by scanning electron microscope.

RESULTS

mBNBD4 was expressed and successfully purified from P. pastoris with intact antimicrobial activity. The recombinant protein was able to enter Raw 264.7 macrophages and exhibited potent in vitro bactericidal activity against M. smegmatis and M. bovis. The cell wall of M. bovis was disrupted after interaction with mBNBD4. Exogenous addition of mBNBD4 to both Raw 264.7 and THP-1 derived macrophages reduced the intracellular survival of M. bovis and M. tuberculosis relative to control cells.

CONCLUSION

Our data show that mBNBD4 plays an important role in inhibiting mycobacterial growth and in controlling intracellular survival of mycobacteria. mBNBD4 could therefore an effective antimycobacterial molecule in combination with other measures.

Temperature dependence of photoluminescence spectra for green light emission from InGaN/GaN multiple wells

Three green light emitting InGaN/GaN multiple quantum well (MQW) structures with different In composition grown by metal-organic chemical vapor deposition are investigated by the X-ray diffraction and the temperature-dependent photoluminescence (PL) measurements. It is found that when the In composition increases in the InGaN/GaN MQWs, the PL spectral bandwidth may anomalously decrease with increasing temperature. The reduction of PL spectral bandwidth may be ascribed to the enhanced non-radiative recombination process which may lower the light emission efficiency of the localized luminescent centers with shallow localization energy in the high-In-content InGaN quantum wells and also cause a reduction of integrated PL intensity.

Validation of a simple universal IELISA for the diagnosis of human brucellosis

The definitive diagnosis of brucellosis requires isolation of the agent, although negative isolation does not rule out the infection. In contrast, serological testing is more sensitive and, therefore, preferred in clinical practice. The majority of reported cases around the world were caused by Brucella melitensis, B. abortus, B. suis and B. canis. The first three species contain O-polysaccharide (OPS) on the cell surface, but B. canis contains no measurable OPS on the rough lipopolysaccharide (R-LPS). A universal indirect enzyme immunoassay for the detection of serum antibody to smooth and rough Brucella spp. in both normal (u-IELISA®) and rapid forms (R-u-IELISA®) has been developed, and, therefore, the potential use of this method was assessed in comparison to cELISA, conventional tests, IELISA and RSAT on a total of 478 sera. The 77 sera from blood donors with no clinical or epidemiological evidence of brucellosis and negative serological tests showed a specificity of 100 % for both u-IELISA® and R-u-IELISA®, with a cut-off value of %P 24 and %P 18, respectively. Sera from 49 culture-positive cases (16 B. suis, 15 B. abortus, 12 B. melitensis and 6 B. canis) yielded a sensitivity of 98 % for u-IELISA® and 95.9 % for R-u-IELISA®. In general, u-IELISA® showed good correlation with cELISA and IELISA for the detection of antibodies to smooth and rough Brucella strains, as well as for monitoring patients during treatment, but R-u-IELISA® seems to need additional optimisation. u-IELISA® is simple to perform and could be a suitable test for field laboratories and hospitals lacking skilled personnel.

MCCC1/LAMP3 reduces risk of sporadic Parkinson's disease in Han Chinese

BACKGROUND

A recent large-scale replication and heterogeneity study reported the new described GWAS locus (MCCC1/LAMP3 rs11711441) was associated with a reduced risk of Parkinson disease (PD) in Asian and Caucasian populations. Its role is still unknown in a Han Chinese population from mainland China. We genotyped the rs11711441 variant to investigate the association with risk of PD.

METHODS

Using a case-control methodology, a total of 1428 Han Chinese study subjects were genotyped. We also conducted further stratified analysis according to age at onset and compared the clinical characteristics of GA + AA subjects with GG subjects.

RESULTS

In this study, we confirmed that the A allele of MCCC1/LAMP3 (rs11711441) polymorphism reduces the risk to develop sporadic PD (P = 0.043). Additionally, subjects with GA + AA genotypes have a reduced risk compared to those with GG genotype (P = 0.022). The association was seen among the older age group (P = 0.014), but was not significant among the younger age group (P = 0.641). No significant differences were observed in gender, age at onset, and onset symptoms between GA + AA subjects and GG subjects.

CONCLUSION

Our study, the first from Mainland China demonstrates that MCCC1/LAMP3 (rs11711441) is associated with a lower risk of PD. Further studies in additional Chinese populations and other cohorts will be useful.

In vitro effect of prion peptide PrP 106–126 on mouse macrophages: Possible role of macrophages in transport and proliferation for prion protein

While there is a growing consensus on the understanding that the immune system plays an important role in facilitating the spread of prion infections from the periphery to the central nervous system, little is known about the key players in the first steps of the infection and about the sites of the disease development. Owing to their subepithelial location and their migratory capacity, macrophages could be early targets for prion transportation or propagation during the later stages of disease. In order to investigate the role of macrophages, we studied in vitro the effect of exposing primary peritoneal macrophages to a synthetic peptide homologous to residues 106-126 of the human prion protein (PrP), PrP 106-126. As shown by MTT assay, macrophage viability treated with less than 50 microM PrP 106-126 for 72 h was not inhibited but slightly stimulated at 10 and 25 microM, while there was significant decrease when exposed to 100 microM PrP 106-126 for 72 h. The expressions of PrP at mRNA and protein level were up-regulated following treatment with PrP 106-126 for 72 h. Cytokine TNF-alpha production were elevated by the PrP peptide in a time-dependent manner, which demonstrated a proinflammatory response linked to the presence and progression of prion disease took place in macrophages. These findings suggested that macrophages may play roles in the transportation and replication of the infectious agent.

[Comparison of effects of 5 and 20 Hz magnetic field on cerebral ischemia in rats]

OBJECTIVE

To compare the effects of 5 Hz and 20 Hz magnetic field on cerebral ischemia in rats.

METHOD

After cerebral ischemia was produced by ligation of the left general carotid artery, rats were stimulated by magnetic fields of 5 Hz and 20 Hz respectively and pathological changes in neurocytes were observed.

RESULT

(1) Different pathological changes were observed in different cells; (2) The extent of damage of pyramidal cells was milder in 5 Hz magnetic field groups than those in the control group, and the effect was not remarkable in the 20 Hz group; (3) The effect on astroglia was worse in 5 Hz group than that in control and 20 Hz group.

CONCLUSION

Magnetic field stimulation influences cerebral ischemic reaction with frequency-dependency.

Store depletion by caffeine/ryanodine activates capacitative Ca(2+) entry in nonexcitable A549 cells

Capacitative Ca(2+) entry is essential for refilling intracellular Ca(2+) stores and is thought to be regulated primarily by inositol 1, 4,5-trisphosphate (IP(3))-sensitive stores in nonexcitable cells. In nonexcitable A549 cells, the application of caffeine or ryanodine induces Ca(2+) release in the absence of extracellular Ca(2+) similar to that induced by thapsigargin (Tg), and Ca(2+) entry occurs upon the readdition of extracellular Ca(2+). The channels thus activated are also permeable to Mn(2+). The channels responsible for this effect appear to be activated by the depletion of caffeine/ryanodine-sensitive stores per se, as evidenced by the activation even in the absence of increased intracellular Ca(2+) concentration. Tg pretreatment abrogates the response to caffeine/ryanodine, whereas Tg application subsequent to caffeine/ryanodine treatment induces further Ca(2+) release. The response to caffeine/ryanodine is also abolished by initial ATP application, whereas ATP added subsequent to caffeine/ryanodine induces additional Ca(2+) release. RT-PCR analyses showed the expression of a type 1 ryanodine receptor, two human homologues of transient receptor potential protein (hTrp1 and hTrp6), as well as all three types of the IP(3) receptor. These results suggest that in A549 cells, (i) capacitative Ca(2+) entry can also be regulated by caffeine/ryanodine-sensitive stores, and (ii) the RyR-gated stores interact functionally with those sensitive to IP(3), probably via Ca(2+)-induced Ca(2+) release.

Effect of erythromycin on ATP-induced intracellular calcium response in A549 cells

ATP induced a biphasic increase in the intracellular Ca(2+)concentration ([Ca(2+)](i)), an initial spike, and a subsequent plateau in A549 cells. Erythromycin (EM) suppressed the ATP-induced [Ca(2+)](i) spike but only in the presence of extracellular calcium (Ca(2+)(o)). It was ineffective against ATP- and UTP-induced inositol 1,4,5-trisphosphate [Ins(1,4,5)P(3)] formation and UTP-induced [Ca(2+)](i) spike, implying that EM perturbs Ca(2+) influx from the extracellular space rather than Ca(2+)release from intracellular Ca(2+) stores via the G protein-phospholipase C-Ins(1,4,5)P(3) pathway. A verapamil-sensitive, KCl-induced increase in [Ca(2+)](i) and the Ca(2+) influx activated by Ca(2+) store depletion were insensitive to EM. 3'-O-(4-benzoylbenzoyl)-ATP evoked an Ca(2+)(o)-dependent [Ca(2+)](i) response even in the presence of verapamil or the absence of extracellular Na(+), and this response was almost completely abolished by EM pretreatment. RT-PCR analyses revealed that P2X(4) as well as P2Y(2), P2Y(4), and P2Y(6) are coexpressed in this cell line. These results suggest that in A549 cells 1) the coexpressed P2X(4) and P2Y(2)/P2Y(4) subtypes contribute to the ATP-induced [Ca(2+)](i) spike and 2) EM selectively inhibits Ca(2+) influx through the P2X channel. This action of EM may underlie its clinical efficacy in the treatment of airway inflammation.

Sequence of the canine c-yes proto-oncogene

Cloning of the canine yes oncogene was attempted from a cDNA library derived from a healthy canine spleen using a human c-yes-1 probe. The nucleotide and amino acid sequences revealed that the canine yes gene contained an open reading frame consisting of 539 amino acids. Its product had a molecular mass of 60,368 Daltons and showed 95.9 per cent and 90.4 per cent homology with human and chick p61c-yes, respectively. Moreover, the product had a myristylation signal, src homology region (SH) 3, SH2, and tyrosine kinase domains showing 98.8 per cent and 96.0 per cent homology with those of human beings and chickens, respectively. These findings indicate that the products of the canine yes gene may have non-receptor-type tyrosine kinase activity on the cell membrane, as is the case in human and chick p61c-yes.

Effects of general anesthetics and pressure on mammalian excitatory receptors expressed in Xenopus oocytes

The effects of general anesthetics and pressure on receptors from the mammalian central nervous system have been investigated using oocyte expression techniques. Poly A+ mRNA extracted from rat whole brain was injected into mature Xenopus oocytes producing depolarizing responses to the fast excitatory neurotransmitters NMDA and kainate and the inhibitory neurotransmitters GABA and glycine. An apparatus was constructed to allow agonist dose-response curves to be determined at high pressures using voltage-clamped oocytes. This was used to investigate the excitatory transmitter kainate. It was found that anesthetics depress the current induced by kainate whereas pressure does not appear to affect the responses associated with this transmitter. Furthermore it was found that pressure does not reverse (or modify in any way) the changes in response brought about by application of anesthetics.

The influence of N2-O2 and He-O2 saturation diving on electroencephalogram of human bodies

This paper reports the changes of the EEG of human bodies during saturation exposure at different depths to different mixed gases. The results of the research show that the most obvious on EEG was the appearance of diffused slow waves, usually theta waves of 4-7 times/s, and delta waves of 2-3 times/s within individual subjects. The EEG changes at 50 m were more obvious than those at 36.5 m. With the prolonging of time under high pressure, the EEG had some improvements, for instance, the slow waves decreased and the alpha waves increased. There was a certain relationship between these changes and the symptoms which appeared in the human body. The chief factor of the EEG changes is due to the effect of nitrogen narcosis during the oxygen-nitrogen diving experiment. In addition, carbon dioxide retention under the high pressure is also a factor of the EEG changes, because repeated inhaling of CO2-dense mixtures could aggravate the EEG changes and the reduction of carbon dioxide in humans by hyperventilation could improve abnormal EEGs. The main changes of the EEG during the helium-oxygen exposure at 302 m were the increase of theta waves, and even of delta waves, the decrease in alpha rhythm and the decline of amplitude of alpha waves. Increased theta index and decreased alpha index could be seen at the depth of 302 m. Under any of the above-mentioned pressure conditions when slow waves characteristic of abnormal changes appeared in the EEGs, the EEGs could be temporarily improved by photic stimulation, i.e. slow waves disappeared and alpha waves reappeared. When photic stimulation was over, alpha waves disappeared and slow waves reappeared. It was indicated that abnormal changes of the EEG under high pressure were a kind of temporary and reversible changes of the brain function.

The influence of acute and chronic hypoxia on the electroencephalogram of human body

This report deals with the study of electroencephalograms of 36 subjects who inhaled hypoxic mixture at the sea level (PO2 is as that at 7000 m above sea level) or in a hypobaric chamber with rapid decompression (as that at 5000-7500 m above sea level) and of 46 subjects who reached high altitude area (5000-8600 m) under chronic hypoxia. The characters of the EEGs at rest during photic stimulation, hyperventilation and convalescence after hypoxia were compared in two experiments. The result of experiments shows that in the same individual, the severer the hypoxia, the more obvious the changes on the EEGs. At the same altitude, acute hypoxia causes more obvious changes on the EEGs than chronic one does, but its speed of recovery is faster than that of chronic hypoxia. Under chronic hypoxia, the changes on the EEGs caused by hyperventilation are slighter than those under acute hypoxia. When photic stimulation is given, there is temporary appearance of alpha waves on the EEGs featuring slow waves under acute and chronic hypoxia. The possible mechanism of changes on the EEGs under acute and chronic hypoxia is also analyzed in this report.

Electrocardiogram made on ascending the Mount Qomolangma from 50 m a. s. l

In May 1975, one female mountaineer and eight male mountaineers of our country once more climbed onto the highest peak of the world Mount Qomolangma from the north slope. At the same time, we recorded 15 electrocardiograms while they were climbing from 7,600 m to the peak(8,848.13m) through radio-operated electrocardiography. In this report we mainly analyze the characteristics of electrocardiogram of six mountaineers who ascended the peak at the stage from 50 m a. s. l. to over 8,200m a. s. l. The result proves that although obvious changes after reaching an altitude above 8,200 m from the plain region should be those of indexes of heart rates, the QRS axis, Q-TR, Q-T/T-Q, P wave and T wave, there is no T wave diphasic, inverted, flat or abnormal shifting of S-T segment in the electrocardiogram of these outstanding mountaineers. This fully proves that those summit climbers are of excellent constitution and good adaptation ability to hypoxia. This also shows that the people who have been trained and acclimatized under hypoxia conditions (including permanent altitude residents and native lowlanders) can maintain normal physiological functions under ultra-anoxia for quite a long time.