[Research progress on global health competency and its models]

At present, the research on Global Health Competencies is mainly conducted in the field of the establishment of competency models and application of indicators. This review summarizes the research progress of the Global Health Competency and its models, and focuses on cutting-edge research from the aspects of target audience, purpose, content, classical model, methods and future development. The competency model is suggested to be adjusted and updated according to the practices of different countries and regions. The research and funding of the competency model in the field of public health is suggested to be strengthened, and the global health and diplomacy are suggested to be combined to enrich and improve the competency model. Finally, this review aims to promote Global Health Competencies research in China, especially to improve the global health talent training system and relevant policies in further research.

[Analysis of factors associated with futile recanalization after endovascular treatment for acute ischemic stroke with large vessels occlusion in anterior intracranial circulation]

Objective: To analyze the related factors of futile recanalization (FR) after emergency endovascular treatment of large artery occlusion in anterior circulation. Methods: Three studies on endovascular treatment of acute anterior circulation large vessels occlusion stroke were selected, and their data were merged for retrospective analysis. Patients were divided into the FR group and favorable prognosis group according to the functional prognosis. Risk factor analysis was conducted using multivariate logistic regression. Results: A total of 1 581 patients were finally included, with 858 (48.9%) patients in favorable prognosis group and 926 (51.91%) patients in FR group. Among them, there were 939 males and 642 females, with a mean age of (65±12) years. Multivariate logistic regression analysis showed that National Institute of Health Stroke Scale (NIHSS) score (OR=1.089,95%CI:1.066-1.113), puncture to recanalization time (OR=0.756, 95%CI:0.586-0.971), age (OR=1.04,95%CI:1.029-1.051), serum glucose (OR=1.101,95%CI:1.062-1.143), systolic blood pressure (OR=1.005,95%CI:1.001-1.010), passes≥3(OR=1.941,95%CI:1.294-2.941)Alberta stroke program early CT (ASPECT) score (OR=0.919,95%CI:0.847-0.996), occlusion site (M1 segment of middle cerebral artery, OR=0.744,95%CI:0.565-0.980) and collateral circulation [(2 points, OR=0.757, 95%CI:0.581-0.985); (3-4 points, adjusted OR=0.640, 95%CI: 0.472-0.866)] were independent factors of FR. Conclusion: The incidence of FR in patients with large artery occlusion in anterior circulation who achieve satisfied reperfusion after endovascular treatment is high. Higher NIHSS score, longer puncture to recanalization time, older age, higher serum glucose and systolic blood pressure are risk factors, while lower ASPECTS, occlusion in cerebral middle M1 segment, better collateral circulation are protective factors.

Improved Measurement of the Evolution of the Reactor Antineutrino Flux and Spectrum at Daya Bay

Reactor neutrino experiments play a crucial role in advancing our knowledge of neutrinos. In this Letter, the evolution of the flux and spectrum as a function of the reactor isotopic content is reported in terms of the inverse-beta-decay yield at Daya Bay with 1958 days of data and improved systematic uncertainties. These measurements are compared with two signature model predictions: the Huber-Mueller model based on the conversion method and the SM2018 model based on the summation method. The measured average flux and spectrum, as well as the flux evolution with the ^{239}Pu isotopic fraction, are inconsistent with the predictions of the Huber-Mueller model. In contrast, the SM2018 model is shown to agree with the average flux and its evolution but fails to describe the energy spectrum. Altering the predicted inverse-beta-decay spectrum from ^{239}Pu fission does not improve the agreement with the measurement for either model. The models can be brought into better agreement with the measurements if either the predicted spectrum due to ^{235}U fission is changed or the predicted ^{235}U, ^{238}U, ^{239}Pu, and ^{241}Pu spectra are changed in equal measure.

Precision Measurement of Reactor Antineutrino Oscillation at Kilometer-Scale Baselines by Daya Bay

We present a new determination of the smallest neutrino mixing angle θ_{13} and the mass-squared difference Δm_{32}^{2} using a final sample of 5.55×10^{6} inverse beta-decay (IBD) candidates with the final-state neutron captured on gadolinium. This sample is selected from the complete dataset obtained by the Daya Bay reactor neutrino experiment in 3158 days of operation. Compared to the previous Daya Bay results, selection of IBD candidates has been optimized, energy calibration refined, and treatment of backgrounds further improved. The resulting oscillation parameters are sin^{2}2θ_{13}=0.0851±0.0024, Δm_{32}^{2}=(2.466±0.060)×10^{-3}  eV^{2} for the normal mass ordering or Δm_{32}^{2}=-(2.571±0.060)×10^{-3}  eV^{2} for the inverted mass ordering.

[Drug resistance and genomic characteristics of a strain of O139 Vibrio cholerae isolated from human bloodstream infection]

Objective: To analyze the drug resistance and genomic characteristics of a strain of serogroup O139 Vibrio cholerae producing cholera toxin isolated from the bloodstream of a person with bacteremia. Methods: The broth dilution method and automatic drug sensitivity analyzer were used to determine the antibiotic sensitivity of the strain. The complete genome sequence of the strain was obtained by using second-generation gene sequencing and nanopore sequencing. BLAST software was used for comparison and analysis with CARD, Resfinder, ISfinder, VFDB, and other databases. The drug-resistant genes, insertion sequences and virulence genes carried by the strain were identified. MEGA 5.1 software was used to construct a genetic phylogenetic tree based on the core genomic single nucleotide polymorphisms. Results: V. cholerae SH400, as the toxigenic strain, carried multiple virulence-related genes and four virulence islands. The strain was resistant to streptomycin, tetracycline and cotrimoxazole, carrying corresponding drug-resistant genes. The strain also carried IncA/C plasmid with the size of 172914 bp and contained 10 drug-resistant genes. Combined with the genomic evolutionary relationship, this study found that the drug-resistant genes and drug-resistant plasmids carried among strains showed certain aggregation. The traditional ST type of strain SH400 was ST69, and the cgMLST type was a new type highly similar to cgST-252. Conclusion: This strain of serogroup O139 V. cholerae carries the ctxAB gene, multiple drug-resistant genes and IncA/C plasmid, and there are multiple drug-resistant islands.

The prognostic value of vasoresponse to nitric oxide in patients with chronic thromboembolic pulmonary hypertension

Background

Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by pulmonary artery obstructions due to organized chronic thrombotic material in major pulmonary arteries. In addition, about half of the patients suffer from a small vessel pulmonary arteriopathy that is a strong predictor of outcomes. Currently available treatment of CTEPH includes interventional strategies such as pulmonary endarterectomy (PEA) and balloon pulmonary angioplasty (BPA), and non-interventional strategies with PH-specific medications. A simple way of assessing small vessel disease is the degree of vasodilation (“vasoresponse”) in response to inhaled nitric oxide (iNO). In idiopathic pulmonary arterial hypertension vasoresponse serves as the best marker for good prognosis and treatment selection. In CTEPH, the prognostic value of vasoresponse remains unclear.

Purpose

We investigated the prognostic value of three definitions of vasoresponse to nitric oxide in patients with CTEPH.

Methods

We studied 325 CTEPH patients who underwent baseline diagnostic right heart catheterization (RHC) with 40ppm iNO testing at a general hospital (AKH) between 1995 and 2019. Cox regression models, adjusting for covariates including age, sex, comorbidities, and markers for disease severity at baseline, such as proBNP, GFR, NYHA functional class, were used to determine the risk of death or lung transplantation with respect to vasoresponse. We analysed three currently used definitions of vasoresponse to nitric oxide – the classical definition (CD) as a 10mmHg reduction in mPAP to a level below 40mmHg; an absolute definition (AD) as a 10mmHg reduction in mPAP regardless of resulting mPAP; and the percent definition (PD) as a 10% reduction in mPAP regardless of resulting mPAP.

Results

Patients had a median age of 62 (interquartile range [IQR]: 50, 71) at time of baseline right heart catheterization and 50% were female. During a median observation time of 5 years (IQR: 2.2, 9.0), the combined endpoint of death or lung transplantation occurred in 88 cases (27%). In the cox regression model PD vasoresponders, showed improved survival when undergoing PEA (p=0.0019). In PD vasoresponsive patients who were not given PEA surgery (n=66), PH medication therapy was associated with improved survival (p=0.0053), whereas BPA had no association with survival (p=0.58). In PD non-vasoresponsive patients who were not given PEA surgery (n=107) BPA improved survival (p<0.0001), whereas PH medication therapy did not improve survival (p=0.08).

Conclusion

The PD vasoresponse to iNO carries valuable prognostic information about freedom from death or lung transplantation in patients with CTEPH. In patients who are not eligible for PEA, PD vasoresponse can improve optimal therapy selection.

Funding Acknowledgement

Type of funding sources: None.

First Measurement of High-Energy Reactor Antineutrinos at Daya Bay

This Letter reports the first measurement of high-energy reactor antineutrinos at Daya Bay, with nearly 9000 inverse beta decay candidates in the prompt energy region of 8-12 MeV observed over 1958 days of data collection. A multivariate analysis is used to separate 2500 signal events from background statistically. The hypothesis of no reactor antineutrinos with neutrino energy above 10 MeV is rejected with a significance of 6.2 standard deviations. A 29% antineutrino flux deficit in the prompt energy region of 8-11 MeV is observed compared to a recent model prediction. We provide the unfolded antineutrino spectrum above 7 MeV as a data-based reference for other experiments. This result provides the first direct observation of the production of antineutrinos from several high-Q_{β} isotopes in commercial reactors.

Joint Determination of Reactor Antineutrino Spectra from ^{235}U and ^{239}Pu Fission by Daya Bay and PROSPECT

A joint determination of the reactor antineutrino spectra resulting from the fission of ^{235}U and ^{239}Pu has been carried out by the Daya Bay and PROSPECT Collaborations. This Letter reports the level of consistency of ^{235}U spectrum measurements from the two experiments and presents new results from a joint analysis of both data sets. The measurements are found to be consistent. The combined analysis reduces the degeneracy between the dominant ^{235}U and ^{239}Pu isotopes and improves the uncertainty of the ^{235}U spectral shape to about 3%. The ^{235}U and ^{239}Pu antineutrino energy spectra are unfolded from the jointly deconvolved reactor spectra using the Wiener-SVD unfolding method, providing a data-based reference for other reactor antineutrino experiments and other applications. This is the first measurement of the ^{235}U and ^{239}Pu spectra based on the combination of experiments at low- and highly enriched uranium reactors.

Improved Constraints on Sterile Neutrino Mixing from Disappearance Searches in the MINOS, MINOS+, Daya Bay, and Bugey-3 Experiments

Searches for electron antineutrino, muon neutrino, and muon antineutrino disappearance driven by sterile neutrino mixing have been carried out by the Daya Bay and MINOS+ collaborations. This Letter presents the combined results of these searches, along with exclusion results from the Bugey-3 reactor experiment, framed in a minimally extended four-neutrino scenario. Significantly improved constraints on the θ_{μe} mixing angle are derived that constitute the most constraining limits to date over five orders of magnitude in the mass-squared splitting Δm_{41}^{2}, excluding the 90% C.L. sterile-neutrino parameter space allowed by the LSND and MiniBooNE observations at 90% CL_{s} for Δm_{41}^{2}<13  eV^{2}. Furthermore, the LSND and MiniBooNE 99% C.L. allowed regions are excluded at 99% CL_{s} for Δm_{41}^{2}<1.6 eV^{2}.

Extraction of the ^{235}U and ^{239}Pu Antineutrino Spectra at Daya Bay

This Letter reports the first extraction of individual antineutrino spectra from ^{235}U and ^{239}Pu fission and an improved measurement of the prompt energy spectrum of reactor antineutrinos at Daya Bay. The analysis uses 3.5×10^{6} inverse beta-decay candidates in four near antineutrino detectors in 1958 days. The individual antineutrino spectra of the two dominant isotopes, ^{235}U and ^{239}Pu, are extracted using the evolution of the prompt spectrum as a function of the isotope fission fractions. In the energy window of 4-6 MeV, a 7% (9%) excess of events is observed for the ^{235}U (^{239}Pu) spectrum compared with the normalized Huber-Mueller model prediction. The significance of discrepancy is 4.0σ for ^{235}U spectral shape compared with the Huber-Mueller model prediction. The shape of the measured inverse beta-decay prompt energy spectrum disagrees with the prediction of the Huber-Mueller model at 5.3σ. In the energy range of 4-6 MeV, a maximal local discrepancy of 6.3σ is observed.

Neurological symptoms in Hypophosphatasia

Hypophosphatasia (HPP) typically manifests with fractures, tooth loss, and muscle pain. Although mental health diagnoses and neurological symptoms have not been previously well documented in HPP, they occur commonly. The recognition of non-traditional symptoms may improve patient satisfaction, preempt costly evaluation and misdiagnosis, and lead to further treatment options.

INTRODUCTION

Hypophosphatasia (HPP) is an inborn error of metabolism due to deficiency of tissue non-specific alkaline phosphatase (TNSALP). It is traditionally characterized by rickets in children and osteomalacia in adults, along with fractures, tooth loss, and muscle pain. Neurological symptoms and mental health diagnoses have not been widely reported, and we therefore report their prevalence in a cohort of patients with HPP.

METHODS

A retrospective chart review was performed on a series of 82 HPP patients. Patient charts were reviewed to identify the possible presence and onset of 13 common neurological symptoms.

RESULTS

Median age was 36 years (2 to 79). Seventeen had adult onset HPP (> 18 years) and 65 had pediatric onset HPP (< 18 years). Median time from symptom onset to HPP diagnosis was 8 years (0 to 67). Seventy-four percent had a family history of bone disease, while 17% had a family history of neurologic disease. Bone problems occurred in 89%, dental problems in 77%, and muscle problems in 66%. Fatigue occurred in 66%, headache in 61%, sleep disturbance in 51%, gait change in 44%, vertigo in 43%, depression in 39%, anxiety in 35%, neuropathy in 35%, and hearing loss in 33%.

CONCLUSIONS

The extra-skeletal manifestations of HPP, specifically neurological symptoms, have not been previously well documented. However, mental health diagnoses and neurological symptoms such as headache and sleep disturbance occur commonly in patients with HPP. The recognition of non-traditional symptoms in HPP may improve patient satisfaction, preempt costly evaluation and misdiagnosis, and may lead to further treatment options.

Correction to: Neurological Symptoms in Hypophosphatasia

Due to a typesetting error the title of the article was published wrongly.

Measurement of the Electron Antineutrino Oscillation with 1958 Days of Operation at Daya Bay

We report a measurement of electron antineutrino oscillation from the Daya Bay Reactor Neutrino Experiment with nearly 4 million reactor ν[over ¯]_{e} inverse β decay candidates observed over 1958 days of data collection. The installation of a flash analog-to-digital converter readout system and a special calibration campaign using different source enclosures reduce uncertainties in the absolute energy calibration to less than 0.5% for visible energies larger than 2 MeV. The uncertainty in the cosmogenic ^{9}Li and ^{8}He background is reduced from 45% to 30% in the near detectors. A detailed investigation of the spent nuclear fuel history improves its uncertainty from 100% to 30%. Analysis of the relative ν[over ¯]_{e} rates and energy spectra among detectors yields sin^{2}2θ_{13}=0.0856±0.0029 and Δm_{32}^{2}=(2.471_{-0.070}^{+0.068})×10^{-3}  eV^{2} assuming the normal hierarchy, and Δm_{32}^{2}=-(2.575_{-0.070}^{+0.068})×10^{-3}  eV^{2} assuming the inverted hierarchy.

[To observe the effect of "Fangfenggubenkeli" on IL-4, IL-5, IL-10 and IFN-γ cytokines in PBMC supernatant of allergic rhinitis patients with lung depression and spleen efficiency]

Objective:To observe the effect of "Fangfenggubenkeli" on IL-4, IL-5, IL-10 and IFN-γ cytokines in PBMC supernatant of allergic rhinitis' patients with lung depression and spleen deficiency.Method:One hundred patients were randomly divided into two groups. The treatment group of 50 cases, was given to ancient side of the "Fangfenggubenkeli". The control group of 50 patients, was given to cetirizine hydrochloride, oral treatment. The levels of IL-4, IL-5, IL-10 and IFN-γ in the two groups were measured before and after treatment of 1 month. The changes of the laboratory indexes were compared between the two groups before and after treatment.Result:The levels of IL-4 in the two groups were significantly lower than those before treatment (P < 0.01), and the levels of IFN-γ were significantly higher than those before treatment (P < 0.01), there was a statistically significant difference.Conclusion:The mechanism of "Fangfenggubenkeli" in patients with allergic rhinitis with lung depression may be related to the IFN-γ level, lower IL-4 level. Thereby Fangfenggubenkeli would improved the Th1/Th2 imbalance state as a whole.

[Prevalence of obstructive sleep apnea hypopnea syndrome in professional drivers and the relationship with traffic accidents]

Objective: To study the prevalence of obstructive sleep apnea hypopnea syndrome (OSAHS) and its relationship with traffic accidents in the professional drivers. Methods: Questionnaires of OSAHS were sent to 950 professional drivers who had annual physical examination at the Central Hospital of Jiading District in Shanghai from October 2014 to September 2015. Those with moderate to severe snoring and/or Epworth Sleepiness Scale (ESS)≥9 performed the home sleep testing. All drivers were divided into OSAHS and non-OSAHS according to the survey and monitoring. The following parameters were compared such as driving ages, neck circumference, body mass index (BMI), average night sleep time, ESS, hypertension, diabetes, hypertrophy of tonsil and the incidence of traffic accidents. The risk factors of traffic accidents were analyzed by multivariate Logistic regression. Results: Totally 826 responses were eligible, including 578 (70.0%) with self-reported snoring. There was measurement failure involving 3 of 233 the home sleep testing due to sensor off, 823 subjects were included in the study. The prevalence of OSAHS was 13.5% (111/823). The mild, moderate and severe OSAHS were 47, 38 and 26 cases respectively. There were 712 drives without OSAHS. The neck circumference[(39.8±3.8) vs (39.0±3.0) cm]and BMI[(26.7±4.2) vs (24.4±3.8) kg/m²]were significantly higher in the drivers suffering from OSAHS (all P<0.05). The percentage of ESS≥ 9 (57.7% vs 12.6%), hypertension (27.9% vs 5.9%), diabetes (4.5% vs 1.1%), hypertrophy of tonsil (7.2% vs 2.3%) were higher in the drivers with OSAHS (all P<0.05). There were no significant difference in driving ages and average night sleep time between two groups (all P>0.05). The overall incidence of traffic accidents was 5.8% (48/823) in a year. The percentage was respectively 17.1% (19/111) in OSAHS and 4.1% (29/712) in non-OSAHS (P<0.001). Multiple logistic regression analysis showed that sleepiness (OR=30.578, 95%CI: 10.699-87.394; P<0.001), OSAHS (OR=14.062, 95%CI: 4.791-41.269; P<0.001) and vehicle years (OR=2.345, 95%CI: 1.183-4.646; P<0.05)were the risk factors, while the average night sleep time (OR=0.037, 95%CI: 0.014-0.098; P<0.001) was the protective factor. Conclusion: Professional drivers have higher prevalence of OSAHS, which contributes to the increased risk of traffic accidents.

Screening for fractions of Oxytropis falcata Bunge with antibacterial activity

Preliminary studies with the four extracts of Oxytropis falcate Bunge exhibited that the chloroform and ethyl acetate extracts showed stronger antibacterial activities against the nine tested Gram-positive and Gram-negative bacteria. The HPLC-scanned and bioassay-guided fractionation led to the isolation and identification of the main flavonoid compounds, i.e. rhamnocitrin, kaempferol, rhamnetin, 2',4'-dihydroxychalcone and 2',4',beta-trihydroxy-dihydrochalcon. Except 2',4',beta-trihydroxy-dihydrochalcon, four other compounds had good antibacterial activities. The minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) of the four compounds ranged between 125 and 515 microg mL(-1). Staphylococcus aureus was the most susceptible to these compounds, with MIC and MBC values from 125 to 130 microg mL(-1). This is the first report of antibacterial activity in O. falcate Bunge. In this study, evidence to evaluate the biological functions of O. falcate Bunge is provided, which promote the rational use of this herb.

[The calculation-improving of stress amplification coefficient and the checking of its trouble-shooting model]

Through mechanical analysis, it is discovered that the twined structure decides the amplification coefficient of the catgut tension. Many troubles of production can be explained with this mechanics model, and it could be used as a reference for medical sutures. The paper gives an accurate calculating formula for catgut design and its direct tensile strength through improving mechanics model. It can raise the material strength from 10 to over 31% depending on its twined structure.

[Pharmacodynamics and clinical therapeutic effects of aerosol and injection of shuanghuanglian]

The results show that both aerosol and injection of shuanghuanglian can increase the activity of NK cells in peripheral blood of the human body as well as the ability of lymphocyte to produce alpha-interferon. Their broad-spectrum antiseptic and virus-inhibiting actions have also been confirmed. The absolute bioavailability of aerosol was 96.88% (baicalin) and 90.69% (chlorogeniacid). The significant response rate of aerosol and injection was 84% and 83% respectively. The total response rate was 92% and 93% respectively.

Growth-related changes in familial resemblance of maxillofacial morphology

We investigated changes in resemblance between Japanese parents and their growing children with regard to maxillofacial morphology. Lateral roentgenographic cephalograms taken from 963 children (336 male and 627 female) over 6 years of age and their parents were used as samples. Based on the age of the children, there were six groups--I: 6-7 years of age; II: 8-9; III: 10-11; IV: 12-13; V: 14-15; and VI: over 16. Parent-offspring heritabilities (h2) were computed for 35 variables representing maxillofacial and dentoalveolar traits, and group comparisons were also made. The following results were obtained: (1) there were more significant heritabilities for maxillofacial variables than those for dentoalveolar ones; (2) in general, additive genetic effects were more prominent in controlling maxillofacial and dentoalveolar structure of on-growing children, with increasing age.

Familial similarity in dental arch form and tooth position

This study was done to quantify and compare similarities in dental arch form and tooth position among individuals of various degrees of biological kinship. The sample consisted of 360 dental casts selected from 102 Japanese families, each including both parents and one of their offspring. Most of the subjects had well-aligned permanent dentitions. Coefficients of dissimilarity were obtained by orienting two standard-sized dental arch diagrams plotted from occlusal photographs to the position of best fit. Dissimilarity between adults and children from different families was computed and served as the control data. With few exceptions, the mean dissimilarity between parents and offspring was smaller than that of the nonfamilial pairings; however, statistical differences were not always significant. Among all the teeth observed, the position of both upper and lower central incisors was found to exhibit the least familial similarity. Analysis of variance among pairings of different sources of variation suggested the existence of significant additive genetic effect, both autosomal and sex-linked. Relative contribution of the additive genetic effect in the total variability of this sample was estimated for dental arch form and tooth position to be in the range of 55-60% and 39-77%, respectively. Autosomal additive genetic effects appear to strongly account for the variation in position of the second premolar and of the first molar.

Heritability of dental arch dimensions in humans

The purposes of this study were to estimate the heritabilities of several human dental arch dimensions and compare the hereditary differences among kinships and among variables. The sample consisted of 102 Japanese families, each including both parents and one of their offspring, and on average all subjects had relatively well-aligned permanent dentitions. The heritabilities of all variables were estimated from the regression of offspring on parent and on midparent. Results showed that genetics played a role regarding dental arch dimensions, and arch perimeter (sum of tooth width) was a more definite genetic-related factor than other arch dimensions, such as width, length, or size. There were few significant hereditary differences between sons and daughters, and between upper and lower arches for each variable. Sex chromosomal involvement was not confirmed, but maternal effects were found to be more evident in daughters than in sons, for both arches. Comparisons among the heritabilities of overall and of anterior arch dimensions indicated that size of the anterior part of the dental arch might be less resistant to environmental factors, especially in case of the lower arch.

Potential application of shape memory plastic as elastic material in clinical orthodontics

Polynorbornen, a shape memory plastic developed in Japan, has a glass transitional point of 35 degrees C. Once the environmental temperature exceeds the critical point, this plastic will begin to display an elastic property, then return to its original shape, if deformed. We examined whether the force generated during the elastic phase of polynorbornen could be used to displace human teeth. We found that the shape memory plastic wire of 1 mm in diameter stretched to two to three times of its original length at a temperature of 50 degrees C and a speed of 0.5 mm/sec would exert a relatively stable continuous light force of 119-156 g to move the teeth. This new material, compared with conventional elastic modules used in orthodontic therapy, exhibited a lesser degree of force degradation at a body temperature of 37 degrees C for a long period, and can be manufactured to near the tooth colour required. These advantages make feasible clinical application of the shape memory plastic in orthodontics.

Agonist-induced down-regulation of m1 muscarinic receptors and reduction of their mRNA level in a transfected cell line

Agonist-induced reduction in both the number of m1 muscarinic receptors and the mRNA coding for the receptor protein was investigated in Chinese hamster ovary (CHO) cells which were transfected with the m1 muscarinic receptor gene. Receptor concentration was measured by the specific binding of the muscarinic ligand, [3H]quinuclidinyl benzilate ([3H]QNB), and Northern blot hybridization analysis was used to evaluate the levels of receptor mRNA. Incubation of cells with 1 mM of the muscarinic agonist, carbamylcholine (CBC), for 24 h decreased receptor density and mRNA levels in cells by 65% and 73%, respectively. These results indicate that agonist-induced down-regulation of m1 muscarinic receptors might be due to, at least in part, a decrease in receptor synthesis resulting from a reduction in the steady-state level of their mRNA.

Selectivity of McN-A-343 in stimulating phosphoinositide hydrolysis mediated by M1 muscarinic receptors

The potency and efficacy of McN-A-343 (McN) in stimulating phosphoinositide (PI) hydrolysis were investigated in Chinese hamster ovary cells transfected with the m1 and m3 muscarinic receptor genes, in comparison with carbamylcholine (CBC). In m1 cells, CBC and McN increased PI hydrolysis by 17- and 9-fold over basal, respectively, with corresponding EC50 values of 4.2 and 4.3 microM. Whereas the maximal stimulatory response to CBC was slightly less in m3 cells (11-fold over basal), McN elicited only up to a 2-fold increase in PI hydrolysis in these cells. Competition binding data with N-[3H]methylscopolamine showed that McN had a higher affinity in m1 than in m3 cells, whereas CBC did not differentiate well between the two receptor subtypes. The partial agonistic activity of McN was demonstrated by its ability to suppress the stimulation by CBC to its own maximal response in both cell lines in a dose-dependent manner and by its low efficacy and the absence of receptor spareness. The PI response to the full agonist CBC in m3 cells was associated with a larger receptor reserve than in m1 cells. Thus, differences in receptor spareness cannot account for the apparent selectivity of McN in activating m1 muscarinic receptors. Differences in the sensitivity of m1 and m3 cells to McN were not due to differences in receptor concentration, despite the fact that the receptor density in m1 cells was 2-fold higher than in m3 cells. Our results suggest an actual selectivity (but not necessarily specificity) of the effects of McN in increasing Pl hydrolysis mediated by M1 receptors.

Endothelin has potent inotropic effects in rat atria

Endothelin, a novel peptide recently isolated from aortic endothelial cells, is one of the most active vasoconstrictors yet characterized. We report that endothelin is also a very potent inotropic substance, as demonstrated in isolated rat heart atria. The effects were observed at nanomolar concentrations and appeared to be due to a direct action of the peptide on the heart muscle cells. Thus, endothelin is not only a powerful vasoconstrictor but also has potent contractile effects on cardiac myocytes.